WO2013133451A1

WO2013133451A1 - Laminate for transparent electroconductive film base material

Info

Publication number: WO2013133451A1
Application number: PCT/JP2013/057108
Authority: WO
Inventors: 久雄奥村; 弘晃辻; 渡部　誉之; 久保　耕司; 俊雄石寺; さと子吉崎
Original assignee: 帝人デュポンフィルム株式会社
Priority date: 2012-03-09
Filing date: 2013-03-07
Publication date: 2013-09-12
Also published as: KR20140138775A; CN104159735B; CN104159735A; KR102087006B1; TWI649200B; TW201350330A

Abstract

The purpose of the present invention is to provide a laminate for a transparent, electroconductive film base material offering both excellent index matching properties and favorable adhesiveness. The present invention is a laminate for a transparent, electroconductive film base material, the laminate having a first readily adhered layer and an optical adjustment layer, in the stated order, on at least one side of a polyester film, wherein the first readily adhered layer contains 50 mass% or more of a polyester resin on the basis of the mass of the first readily adhered layer, the refractive index being 1.60-1.65 and the thickness being 8-30 nm.

Description

Laminate for transparent conductive film substrate

The present invention relates to a laminate used as a substrate of a transparent conductive film having a patterned transparent conductive layer that can be used as a sensor electrode of a projected capacitive touch panel.

In recent years, a projected capacitive touch panel has been used as an input device for mobile devices such as mobile phones and smartphones. In recent years, the projected capacitive touch panel has rapidly increased in mobile devices due to its ease of use through intuitive operations such as the multi-touch function that allows multiple fingers to operate simultaneously and the gesture input function. Yes.
The capacitive touch panel has a configuration in which a capacitive touch sensor is arranged on a display device such as a liquid crystal display. Such a capacitive touch sensor detects an electric field disturbance due to a capacitance of a human finger. There are two types of sensor base materials: glass substrates and film substrates. The film base sensors can be continuously produced by roll-to-roll and are relatively inexpensive to manufacture. It has many features that are preferable as a sensor base material for mobile devices, such as being strong against impacts and being hard to break, and being light and thin, and its application range has expanded in recent years.
The capacitive touch sensor uses, as an electrode, a transparent conductive film having a transparent conductive layer patterned (patterned) into a thin line or a diamond shape for position detection. It is the structure which piled up facing each other. Patterning is performed by drawing a desired pattern by photolithography or screen printing, and then etching. At this time, there is a difference in the optical characteristics between the portion where the transparent conductive layer is present and the portion where the transparent conductive layer is removed. A so-called “bone appearance” phenomenon occurs in which the pattern of the conductive layer is visually recognized.
In order to solve this problem of bone appearance, a so-called index matching technique is known in which an optical adjustment layer is formed by laminating thin films having different refractive indexes and the difference in optical characteristics is eliminated by utilizing the light interference effect. (Patent Documents 1 to 10).
By the way, as a base material of a transparent conductive film used for a touch panel, a biaxially oriented polyester film, particularly a biaxially oriented polyethylene terephthalate film, which has an excellent balance between various properties such as heat resistance, mechanical properties, and optical properties and a price has been conventionally used. Have been used. In addition, since the surface of the biaxially oriented polyester film is generally poor in affinity, when laminating thin films having different refractive indexes, for example, on the film substrate, an easy adhesion component is applied, There is known a technique for forming (Patent Document 11).
Polyester films, particularly uniaxial or biaxial stretched films of polyethylene terephthalate, are often used as various optical films such as protective films and antireflection films for flat panel displays in addition to the above-mentioned touch panel applications. . However, even if an attempt is made to laminate a functional layer such as a hard coat layer for suppressing the generation of scratches on the film surface or an antireflection layer for suppressing light reflection, the surface has an affinity as described above. Since it is scarce and has poor adhesion, it is common to use a laminated film in which an easy-adhesion layer is usually provided on the film surface by in-line coating or off-line coating. In this case, when the difference between the refractive index of the polyester film and / or the functional layer and the refractive index of the easy-adhesion layer becomes large, there is a problem that color spots due to light interference spots occur. In addition, this interference spot is more perceived under the special fluorescent lamp called a three wavelength fluorescent lamp rather than sunlight or an incandescent lamp. In order to solve such a problem, it has been proposed to increase the refractive index of the easy-adhesion layer so that the refractive index is intermediate between the polyester film and the functional layer, and to adjust the thickness.
For example, Patent Document 12 discloses that the easy-adhesion layer has a refractive index of 1.55 to 1.62 which is an intermediate between the refractive index of the stretched polyester film and the hard coat layer, and has a thickness of 50 to 150 nm. And a method of using a high glass transition temperature polyester having a 2,6-naphthalenedicarboxylic acid component and a low glass transition temperature polyester containing a trimellitic acid component as an easy-adhesion layer is described. . Patent Document 13 discloses a method of providing an easy-adhesion layer mainly composed of a copolyester containing a naphthalenedicarboxylic acid component and a glycol component having a bisphenol A skeleton, and Patent Document 14 discloses 2,6-naphthalene dicarboxylic acid. A method has been proposed in which a copolyester containing an acid component and an ethylene oxide adduct component of bisphenolfluorene is contained as one component, and an easy adhesion layer having a thickness of 50 to 200 nm is provided.
JP 2011-142089 A JP 2011-136562 A JP 2011-134482 A JP 2011-116128 A JP 2011-084075 A JP 2011-076932 A JP 2011-044145 A JP 2010-027294 A JP 2010-023282 A JP 2009-076432 A JP 2002-155156 A JP 2007-253512 A JP 2009-126035 A JP 2010-284944 A

In recent years, with an increase in the image quality of displays, a touch sensor in which “bone appearance” is further suppressed has been demanded. However, in response to such a demand, a general easy-adhesive polyester used for a conventional resistive film type film sensor electrode as a substrate of a transparent conductive film having a patterned transparent conductive layer. Even if a film is applied, it is insufficient. The present inventors have found that the degree of bone appearance differs depending on the characteristics of the easy-adhesion layer laminated on the polyester film, and have focused on this. This is considered to be caused by optical interference between the high refractive index layer of the optical adjustment layer, the easy adhesion layer and the polyester film.
On the other hand, when an optical adjustment layer (particularly a high refractive index layer) is formed without having an easy-adhesion layer, sufficient adhesion cannot be obtained and delamination occurs.
Then, an object of this invention is to provide the laminated body for transparent conductive film base materials which made the outstanding index matching characteristic and favorable adhesiveness compatible.
As a result of intensive studies to solve the above-mentioned problems, the present inventors applied an easy-adhesion layer that satisfies the following characteristics, thereby suppressing the influence of optical interference caused by the easy-adhesion layer and providing a good bone appearance suppression effect. At the same time, it was found that sufficient adhesion was obtained, and the present invention was completed.
That is, the laminate of the present invention adopts the following configuration.
1. A laminated body having a first easy-adhesion layer and an optical adjustment layer in this order on at least one surface of the polyester film, wherein the first easy-adhesion layer is 50 masses based on the mass of the first easy-adhesion layer. % Or more, a refractive index of 1.60 to 1.65, and a thickness of 8 to 30 nm, a laminate for a transparent conductive film substrate.
2. The average refractive index in the plane direction of the polyester film is 1.60 to 1.70, and the optical adjustment layer is composed of a high refractive index layer disposed on the first easy adhesion layer side and a low refractive index layer thereon, 2. The laminate for a transparent conductive film substrate according to 1 above, wherein the refractive index layer has a refractive index of 1.60 to 1.80 and the low refractive index layer has a refractive index of 1.40 to 1.60.
3. 3. The laminate for a transparent conductive film substrate according to 1 or 2 above, wherein the first easy-adhesion layer contains metal oxide particles having a refractive index of 1.7 to 3.0.
4). 4. The laminate for a transparent conductive film substrate according to any one of 1 to 3 above, wherein the refractive index of the polyester resin in the first easy-adhesion layer is 1.58 to 1.65.
5. The transparent conductive material according to any one of 1 to 4 above, wherein the polyester resin in the first easy-adhesion layer is a copolymerized polyester resin containing a naphthalene dicarboxylic acid component and / or a diol component having a fluorene structure as a copolymerization component. Laminate for conductive film substrate.
6). 6. A transparent conductive film comprising a patterned transparent conductive layer having a refractive index of 1.9 to 2.3 on the optical adjustment layer in the laminate according to any one of 1 to 5 above.
7). The laminate according to any one of 1 to 6, wherein the laminate has a first easy-adhesion layer and an optical adjustment layer in this order on one side of the polyester film, and a second easy-adhesion layer on the other side. A laminate in which the second easy-adhesion layer contains 70% by mass or more of the following copolyester based on the mass of the second easy-adhesion layer.
Copolyester:
(A1) 60-90 mol% of naphthalenedicarboxylic acid component,
(B1) 0 to 40 mol% of the alkylene dicarboxylic acid component having 6 to 12 carbon atoms, 0 to 50 mol% of the alkylene glycol component having 4 to 10 carbon atoms, and the total of the alkylene dicarboxylic acid component and the alkylene glycol component is 15 Copolyester containing ~ 50 mol% and (C1) 5 mol% or more and less than 20 mol% of a glycol component having a fluorene structure represented by the following formula (I).
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)

(R ₁ is an alkylene group having 2 to 4 carbon atoms, R ₂ , R ₃ , R ₄ , and R ₅ are hydrogen, an alkyl group having 1 to 4 carbon atoms, an aryl group, or an aralkyl group. Or different.)
8). 8. The laminate according to 7 above, wherein the second easy-adhesion layer contains 1 to 30% by mass of the following crosslinkable addition polymer based on the mass of the second easy-adhesion layer.
Crosslinkable addition polymer:
(X1) containing 10 to 80 mol% of an addition polymerizable oxazoline group-containing monomer unit,
(Y1) A crosslinkable addition polymer having an addition polymerizable polyalkylene oxide group-containing monomer unit content of 5 mol% or less.
(The above mol% is a value based on 100 mol% of all monomer units of the crosslinkable addition polymer.)
9. The copolymerized polyester further contains (F1) a dicarboxylic acid component having a sulfonate group in an amount of 0.1 to 5 mol%.
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
The laminated body of said 7 containing.
10. The laminate according to any one of 1 to 6 above, wherein the polyester film has a first easy-adhesion layer and an optical adjustment layer in this order on one side of the polyester film, and the average refractive index in the plane direction of the polyester film is 1.63. To 1.68, the refractive index is 1.58 to 1.64 on the other surface, the swelling rate obtained by the following method is 130 to 200% in any solvent, and the thickness is 50 to 100 nm. A laminate having two easy-adhesion layers.
Swelling rate:
On the second easy-adhesion layer of the laminate, a coating solution (solid content concentration 40% by mass) obtained by diluting the following UV curable composition with a solvent (methyl ethyl ketone, ethyl acetate, toluene, isopropanol or propylene glycol monomethyl ether) was applied. The hard coat layer having a thickness of 5 μm is formed by drying and curing, the thickness dh of the second easy-adhesion layer after forming the hard coat layer, and the thickness d0 of the second easy-adhesion layer before forming the hard coat layer From the above, the swelling ratio E (%) = value obtained as dh / d0 × 100.
UV curable composition:
Pentaerythritol acrylate: 45% by mass
N-methylolacrylamide: 40% by mass
N-vinylpyrrolidone: 10% by mass
1-hydroxycyclohexyl phenyl ketone: 5% by mass

The laminated body of this invention is the structure which laminated | stacked the 1st easily bonding layer and the optical adjustment layer in this order on the at least single side | surface of the polyester film.
Moreover, the transparent conductive film of this invention is a structure which has the transparent conductive layer further patterned on the optical adjustment layer in the said laminated body.
Hereinafter, each component constituting the present invention will be described.
<Polyester film>
(polyester)
In the present invention, the polyester constituting the polyester film is an aromatic dibasic acid or an ester-forming derivative thereof (which is an acid component in the polyester) and a diol or an ester-forming derivative thereof (which is a glycol component in the polyester). Is a linear saturated polyester synthesized from Specific examples of such polyester include polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, poly (1,4-cyclohexylenedimethylene terephthalate), and polyethylene-2,6-naphthalate. Further, these copolymers, blends thereof, or blends of these with a small proportion of other resins may be used. Among these polyesters, polyethylene terephthalate and polyethylene-2,6-naphthalate are preferable because of a good balance between mechanical properties and optical properties. In particular, polyethylene terephthalate has a refractive index after biaxial stretching (average refractive index in the plane direction) close to 1.65, and thus the average refractive index in the plane direction of the polyester film is easily in the range of 1.60 to 1.70. The refractive index adjustment with the optical adjustment layer in the invention is easy to perform, and thereby a better bone appearance suppressing effect can be obtained, which is preferable.
The polyester may be a homopolymer, but the copolymer component (copolymeric acid component or copolymer glycol component) does not impair its properties, for example, 5 mol% or less with respect to 100 mol% of the total acid component, Preferably, it may be a copolymer copolymerized at a ratio of 3 mol% or less. Examples of the copolymer acid component include aromatic dicarboxylic acid components such as a phthalic acid component, an isophthalic acid component, and a 2,6-naphthalenedicarboxylic acid component, an adipic acid component, an azelaic acid component, a sebacic acid component, and 1,10-decane. An aliphatic dicarboxylic acid component such as a dicarboxylic acid component can be exemplified, and examples of the copolymer glycol component include an aliphatic diol component such as a 1,4-butanediol component, a 1,6-hexanediol component, and a neopentyl glycol component, An alicyclic diol component such as 1,4-cyclohexanedimethanol component can be exemplified. These can also be used together.
Further, as another copolymer component, a compound having two ester-forming functional groups in the molecule other than the above can be used. Examples of such compounds include oxalic acid, dodecanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, phenylindanedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, tetralindicarboxylic acid, decalindicarboxylic acid. , Components derived from dicarboxylic acids such as diphenyl ether dicarboxylic acid, components derived from oxycarboxylic acids such as p-oxybenzoic acid and p-oxyethoxybenzoic acid, or propylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene Glycol, cyclohexanemethylene glycol, neopentyl glycol, ethylene oxide adduct of bisphenolsulfone, ethylene oxide adduct of bisphenol A, diethylene glycol, poly A component derived from a dihydric alcohol such as ethylene oxide glycol can be preferably used. These compounds may be used alone or in combination of two or more. Of these, the acid component is preferably a component derived from 4,4′-diphenyldicarboxylic acid, 2,7-naphthalenedicarboxylic acid, or p-oxybenzoic acid, and the glycol component is trimethylene glycol. , A component derived from an ethylene oxide adduct of hexamethylene glycol neopentyl glycol and bisphenol sulfone.
In the present invention, the polyester constituting the polyester film is particularly preferably polyethylene terephthalate. Such polyethylene terephthalate may have a copolymer component as described above, but preferably has an ethylene terephthalate unit of 90 mol% or more, preferably 95% or more, more preferably 97% or more. Particularly preferred is homopolyethylene terephthalate. As the copolymer component, isophthalic acid is preferred.
The polyester in the present invention is a conventionally known method, for example, a method of directly obtaining a low-polymerization degree polyester by reaction of dicarboxylic acid and glycol, or a lower alkyl ester of dicarboxylic acid and glycol is a conventionally known transesterification catalyst. Obtained by a method in which a polymerization reaction is performed in the presence of a polymerization catalyst after reacting with one or more of compounds containing sodium, potassium, magnesium, calcium, zinc, strontium, titanium, zirconium, manganese, and cobalt. Can do. As a polymerization catalyst, antimony compounds such as antimony trioxide and antimony pentoxide, germanium compounds represented by germanium dioxide, tetraethyl titanate, tetrapropyl titanate, tetraphenyl titanate or a partial hydrolyzate thereof, titanyl ammonium oxalate , Titanium compounds such as potassium titanyl oxalate and titanium trisacetylacetonate can be used.
The polyester may be converted into chips after melt polymerization, and further subjected to solid phase polymerization under heating under reduced pressure or in an inert gas stream such as nitrogen.
The intrinsic viscosity of the polyester is preferably 0.40 dl / g or more, and more preferably 0.40 to 0.90 dl / g. If the intrinsic viscosity is less than 0.40 dl / g, process cutting may occur frequently. If it is higher than 0.9 dl / g, melt extrusion is difficult because of high melt viscosity, and the polymerization time is long and uneconomical.
(Polyester film)
The polyester film in the present invention preferably has an average refractive index in the plane direction of 1.60 to 1.70. Thereby, it is more excellent in a bone appearance suppression effect by the synergistic effect with the other layer which comprises the laminated body of this invention. Here, the average refractive index in the plane direction is an average refractive index between a refractive index in an arbitrary direction and a refractive index in a direction perpendicular to the refractive index in the film plane, preferably the maximum refractive index in the film plane and the maximum The average refractive index of the refractive index in the direction perpendicular to the direction indicating the refractive index is shown. If the average refractive index in the plane direction is too low or too high, the effect of suppressing bone appearance is reduced. From this viewpoint, the range of the average refractive index in the plane direction of the polyester film is more preferably 1.62 or more, further preferably 1.63 or more, particularly preferably 1.64 or more, and most preferably 1.65 or more. Moreover, 1.68 or less is more preferable, 1.67 or less is further more preferable, and 1.66 or less is especially preferable.
In addition, when the average refractive index in the plane direction is in this range, as described later, when a functional layer such as a hard coat layer is provided on the surface opposite to the optical adjustment layer of the polyester film, the second easy-adhesion layer is provided. When a layer having a relatively low refractive index such as a hard coat layer is formed thereon, the occurrence of interference spots can be suppressed. In terms of suppressing such interference spots, the average refractive index in the plane direction is preferably 1.63 to 1.68, more preferably 1.64 to 1.67, and still more preferably 1.65 to 1.66. Yes, if it is too high or too low outside this range, it is difficult to suppress the occurrence of interference spots.
Such a polyester film may be any of an unoriented film, a uniaxially oriented film, and a biaxially oriented film as long as the average refractive index in the plane direction satisfies the above requirements. From the viewpoint, a biaxially oriented film is preferable.
(Polyethylene terephthalate film)
In order to achieve such an average refractive index in the plane direction, it is preferable to employ, for example, the above-described polyethylene terephthalate (PET) as the polyester constituting the film. Moreover, it is effective to adopt the conditions described later as the stretching conditions in order to achieve the average refractive index in the plane direction.
In the present invention, an oriented polyethylene terephthalate film is preferably used. The polyester constituting the oriented polyethylene terephthalate film is a polyester having an ethylene terephthalate unit of 95 mol% or more, preferably 98 mol% or more, based on all repeating units, and particularly preferably a homopolyester not using a copolymer component in combination. It is. In the case of copolymerized polyethylene terephthalate, for example, a dicarboxylic acid component such as isophthalic acid or naphthalenedicarboxylic acid or a glycol component such as diethylene glycol, butanediol, or cyclohexanediol can be used as the copolymerization component.
(Other components of polyester film)
The polyester film can contain a slippery filler such as inert particles in order to ensure transportability. On the other hand, for example, a capacitive touch sensor is formed by laminating a plurality of transparent films, and the haze of the film is integrated. Therefore, it is desired that the internal haze of each constituent film is as low as possible. Thus, from the viewpoint of maintaining high transparency in optical applications, the polyester film preferably contains no filler or substantially no filler (for example, 10 ppm or less, preferably 1 ppm or less). However, a small amount of filler may be included as a lubricant in order to prevent minute scratches in the manufacturing process and improve the film winding property. As the filler, for example, inert particles having an average particle diameter of 0.01 to 2 μm, further 0.05 to 1 μm, and particularly 0.1 to 0.3 μm may be used. The blending ratio is preferably 100 ppm or less, for example, based on the mass of the layer to be blended, and may be 10 ppm or less, particularly 1 ppm or less, which is a range that does not substantially contain.
The polyester film can also contain a colorant, an antistatic agent, an antioxidant, an organic lubricant, and a catalyst.
<First easy adhesive layer>
In the present invention, the adhesion between the polyester film and the optical adjustment layer can be enhanced by the first easy-adhesion layer. In the present invention, a polyester film having a first easy-adhesion layer and / or a second easy-adhesion layer described later may be referred to as a laminated polyester film.
(Refractive index of the first easy-adhesion layer)
In the present invention, it is important that the refractive index of the first easy-adhesion layer is in the range of 1.60 to 1.65. Thereby, it is excellent in the bone appearance suppression effect by the synergistic effect with the other layer which comprises the laminated body of this invention. If the refractive index of the first easy-adhesion layer is too low, the optical interference becomes too large, so that the bone appearance suppressing effect cannot be obtained. Ideally, the polyester film, the first easy-adhesion layer, and the optical adjustment layer (or the high refractive index layer in the optical adjustment layer) preferably all have the same refractive index. When trying to achieve a refractive index exceeding, it tends to be difficult to increase the transparency of the first easy-adhesion layer. Considering these balances, the refractive index of the first easy-adhesion layer is preferably 1.61 to 1.64, more preferably 1.62 to 1.64.
The difference between the refractive index of the first easy-adhesion layer and the refractive index of the high refractive index layer described later is preferably 0.05 or less. According to such an embodiment, the effect of improving bone appearance suppression can be increased. The refractive index difference is more preferably 0.04 or less, and still more preferably 0.03 or less.
Moreover, it is preferable that the difference of the refractive index of a 1st easily bonding layer and the surface direction average refractive index of a polyester film is 0.05 or less. According to such an embodiment, the effect of improving bone appearance suppression can be increased. The refractive index difference is more preferably 0.04 or less, and still more preferably 0.03 or less.
(The thickness of the first easy-adhesion layer)
The thickness of the first easy-adhesion layer is 8 to 30 nm. Thereby, it is excellent in adhesiveness. Moreover, while making the refractive index of a 1st easily bonding layer into the range mentioned above, and making thickness into the said range, there exists an outstanding bone-inhibition suppression effect by interaction with the other layer in the laminated body of this invention. be able to.
The optical interference of the thin film depends on the product of the refractive index and the optical path length (film thickness). As a result of conducting further detailed studies on this, the present inventors have found that the optical adjustment layer or the high refractive index layer in the optical adjustment layer is in the refractive index range described later, and the first easy-adhesion layer is in the refractive index range. In some cases, it has been found that by controlling the film thickness of the first easy-adhesion layer within a very narrow range of 8 to 30 nm, excellent adhesiveness can be obtained while exhibiting an excellent bone appearance suppressing effect. If the thickness of the first easy-adhesion layer is too thick, the effect of suppressing bone appearance is reduced. On the other hand, if it is too thin, the adhesiveness decreases. From this viewpoint, the thickness of the first easy-adhesion layer is preferably 10 nm or more, more preferably 15 nm or more, still more preferably 18 nm or more, and preferably 25 nm or less, more preferably 22 nm or less.
(Polyester resin of the first easy-adhesion layer)
In the first easy-adhesion layer in the present invention, the polyester resin occupies 50% by mass or more based on the mass of the first easy-adhesion layer. Thereby, it is excellent in adhesiveness. From this viewpoint, the content of the polyester resin is preferably 70% by mass or more, and more preferably 80% by mass or more. The upper limit of the content of the polyester resin in the first easy-adhesion layer is not particularly limited, but the polyester resin occupies the remaining part other than the components that can be preferably contained in the first easy-adhesion layer, which will be described later. What is necessary is just to be an aspect.
In this invention, although a polyester resin is used as a binder component which forms a 1st easily bonding layer, it is preferable that the glass transition temperature (Tg) of this polyester resin is 120 degrees C or less. Thereby, it is further excellent in adhesiveness. Moreover, it can be set as the 1st easily bonding layer excellent in extending | stretching followability (film-forming property), smooth and excellent in transparency. From this viewpoint, Tg is more preferably 100 ° C. or less, further preferably 80 ° C. or less, and particularly preferably 75 ° C. or less. Moreover, it is preferable that the minimum of Tg of a polyester resin is 40 degreeC, and this is further excellent in adhesiveness, and is excellent in blocking resistance. From this viewpoint, Tg is more preferably 50 ° C. or higher, and particularly preferably 60 ° C. or higher.
As this polyester resin, the polyester or copolymer polyester which consists of an acid component and a glycol component as shown below can be mentioned. In the present invention, a copolyester is preferable from the viewpoint of adhesiveness. In addition, although the monomer component which comprises the polyester concerning the following is illustrated, it is not limited to these.
Acid components include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, pyromellitic acid, dimer acid, Examples include components derived from 5-sodium sulfoisophthalic acid and the like. It is preferable to use two or more of these acid components as a copolyester. Further, an unsaturated polybasic acid component such as maleic acid, itaconic acid and the like, and hydroxycarboxylic acid such as p-hydroxybenzoic acid, etc., can also be used in a slight amount. In the present invention, 2,6-naphthalenedicarboxylic acid is preferably used from the viewpoint of achieving a balance between the refractive index and the coating film strength. As content of 2, 6- naphthalene dicarboxylic acid in a polyester resin, 50 mol% or more is preferable with respect to 100 mol% of all the acid components, and 60 mol% or more is more preferable. Moreover, 90 mol% or less is preferable, 80 mol% or less is more preferable, and 70 mol% or less is more preferable. When there is too much content of this component, it exists in the tendency for the film forming property of a 1st easily bonding layer to fall. On the other hand, if the amount is too small, the effect of improving the refractive index is small, and the effect of improving the mechanical properties is small.
Examples of the glycol component include ethylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylene glycol, dimethylolpropane, poly (ethylene oxide) glycol, poly The component derived from (tetramethylene oxide) glycol etc. can be mentioned. It is preferable to use two or more of these glycol components as a copolyester. In the present invention, in order to effectively increase the refractive index of the first easy-adhesion layer, a fluorene structure represented by the following formula (I) such as bis (4-hydroxyethoxyphenyl) fluorene component is preferably used. A compound having a conjugated system, such as a glycol component, is preferably used as the copolymer component.

(R ₁ Is an alkylene group having 2 to 4 carbon atoms, R ₂ , R ₃ , R ₄ And R ₅ Are hydrogen, an alkyl group having 1 to 4 carbon atoms, an aryl group or an aralkyl group, which may be the same or different. )
As content of the glycol component which has a fluorene structure in a polyester resin, 2 mol% or more is preferable with respect to 100 mol% of all the acid components, 4 mol% or more is more preferable, and 6 mol% or more is further more preferable. Moreover, 10 mol% or less is preferable and 8 mol% or less is more preferable. When there is too much content of this component, it exists in the tendency for the film forming property of a 1st easily bonding layer to fall. On the other hand, if the amount is too small, the effect of improving the refractive index is small.
In the present invention, among these components, a 2,6-naphthalenedicarboxylic acid component is adopted as the acid component, and at the same time, a glycol component having a fluorene structure, preferably a bis (4-hydroxyethoxyphenyl) fluorene component, is used as the glycol component. The embodiment adopted is preferred. Thereby, it becomes easier to set the refractive index of the first easy-adhesion layer within the range defined by the present invention, and at the same time, the mechanical properties are excellent, and the effect of improving adhesiveness can be enhanced. An embodiment in which these components are contained in the polyester resin at the above-described contents is preferable.
In addition, as a polyester resin constituting the first easy-adhesion layer in the present invention based on the above idea, a copolymer polyester resin constituting a second easy-adhesion layer described later can be employed. By doing so, since the same effect as the effect which employ | adopts the copolyester resin which comprises this 2nd easily bonding layer can be provided to a 1st easily bonding layer, it is preferable.
A particularly preferred embodiment of the polyester resin constituting the first easy-adhesion layer in the present invention is that the total acid component is 100 mol%, the acid component is 2,6-naphthalenedicarboxylic acid 60 to 70 mol%, and isophthalic acid 25 ~ 30 mol%, 5-sodium sulfoisophthalic acid is 5-10 mol%, glycol component is 10-20 mol% bisphenol A, ethylene glycol is 35-60 mol%, trimethylene glycol is 25-35 mol% %, And bis (4-hydroxyethoxyphenyl) fluorene consists of 5 to 10 mol%.
The polyester resin is preferably a polyester that is soluble or dispersible in water (which may contain some organic solvent), and it is easy to produce a coating liquid described later.
(Metal oxide particles)
In order to control the refractive index of the first easy-adhesion layer in the present invention, metal oxide particles having a refractive index of 1.7 to 3.0, preferably 1.8 to 2.2 may be added. preferable. As this metal oxide particle, TiO ₂ (Refractive index 2.5), ZrO ₂ (Refractive index 2.4), SnO ₂ (Refractive index 2.0), Sb ₂ O ₃ (Refractive index 2.0) is exemplified, and in the present invention, it is preferable to use at least one metal oxide particle selected from the group consisting of these.
In order to achieve a high degree of transparency, in order to avoid optical scattering by the metal oxide particles in the first easy-adhesion layer, the metal oxide particles are colorless and transparent and have a particle size sufficiently small with respect to the wavelength of light. (For example, 400 nm or less, preferably 100 nm or less) is preferable. A higher refractive index is preferable because the refractive index of the first easy-adhesion layer can be increased with a small amount, but high refractive index metal oxide particles having a refractive index exceeding 3.0 tend to be inferior in transparency. In addition, since there are many special rare metals, the manufacturing cost tends to increase.
From such a viewpoint, as the metal oxide particles of the first easy-adhesion layer in the present invention, particles made of titanium oxide and zirconium oxide are more preferable. From the viewpoint of specific gravity, titanium oxide particles having a high refractive index improving effect in a small amount. Particularly preferred.
The addition amount of the metal oxide particles is preferably 2% by mass or more and 20% by mass or less based on the mass of the first easy-adhesion layer, and the refractive index can be efficiently maintained while maintaining transparency by making such a range. Can be high. If the amount is too large, the transparency tends to decrease. In addition, particle dropping or the like tends to occur, equipment wear occurs during coating, and stable coating tends to be difficult. On the other hand, if the amount is too small, the effect of improving the refractive index is lowered. From this viewpoint, it is more preferably 3% by mass or more, further 4% by mass or more, particularly preferably 5% by mass or more, more preferably 15% by mass or less, still more preferably 10% by mass or less, and further preferably 8% by mass or less. Is particularly preferred.
In order to increase the refractive index of the first easy-adhesion layer, as described above, means such as a method of adding a high refractive index filler such as metal oxide particles or a method of increasing the refractive index of a polyester resin as a binder component However, the use of metal oxide particles has a problem of equipment wear and is relatively difficult to add in a large amount. On the other hand, when trying to increase the refractive index of the binder component, since the glass transition temperature tends to increase at the same time, the coating film is cracked in the stretching process and the film haze is increased because it cannot follow the deformation during stretching. Such problems are likely to occur. Therefore, from these restrictions, it is necessary to appropriately balance the constitution and refractive index of the binder component (polyester resin) and the refractive index and addition rate of the metal oxide particles. The aspect which employ | adopts simultaneously is the most preferable.
(Lubricant particles)
It is preferable that the 1st easily bonding layer in this invention contains the lubricant particle for providing lubricity other than the metal oxide particle of the said specific refractive index range. By containing the lubricant particles, it is possible to impart lubricity and scratch resistance to the film.
Examples of such lubricant particles include inorganic lubricant particles such as calcium carbonate, magnesium carbonate, calcium oxide, silicon oxide, sodium silicate, aluminum hydroxide, and carbon black, acrylic cross-linked polymers, styrene cross-linked polymers, and silicones. Examples thereof include organic lubricant particles such as resin, fluororesin, benzoguanamine resin, phenol resin, and nylon resin. These may be used alone or in combination of two or more.
The average particle diameter of the lubricant particles is preferably 10 to 180 nm, more preferably 20 to 150 nm. The thickness of the first easy-adhesion layer of the present invention is very thin with respect to 80 to 120 nm which is the thickness of the easy-adhesion layer in a normal optical film. If it is smaller than 10 nm, sufficient lubricity and scratch resistance may not be obtained.
The content of the lubricant particles is preferably 0.1 to 10% by mass per 100% by mass of the first easy-adhesion layer. If it is less than 0.1% by mass, sufficient lubricity and scratch resistance cannot be obtained, and if it exceeds 10% by mass, the surface haze tends to increase, and the optical properties tend to deteriorate.
(Crosslinking agent)
In the present invention, it is preferable to add a crosslinking agent for the purpose of improving the coating strength of the first easy-adhesion layer and for enhancing the effect of improving the adhesiveness.
The crosslinking agent is preferably a compound having an oxazoline group and a polyalkylene oxide chain, more preferably an acrylic resin having an oxazoline group and a polyalkylene oxide chain, from the viewpoint of improving the coating film strength and further improving the adhesiveness. Use. An acrylic resin is preferable because it can easily copolymerize many kinds of functional groups. The acrylic resin having an oxazoline group and a polyalkylene oxide chain is preferably an acrylic resin that is soluble or dispersible in water (may contain some organic solvent). In addition, since the acrylic resin has a low refractive index, the addition of such components leads to a decrease in the refractive index of the first easy-adhesion layer, and therefore the amount of addition must be sufficiently careful.
Examples of the acrylic resin having an oxazoline group and a polyalkylene oxide chain include those containing the following monomers as components.
Examples of the monomer having an oxazoline group include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, Examples include 2-isopropenyl-4-methyl-2-oxazoline and 2-isopropenyl-5-methyl-2-oxazoline. These may be used alone or in a mixture of two or more. Among these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially. By using an acrylic resin having an oxazoline group, the cohesive force of the first easy-adhesion layer is improved, and the adhesiveness with the optical adjustment layer or the high refractive index layer becomes stronger. Further, it is possible to impart scratch resistance to the metal roll in the film forming process or in the processing process of the optical adjustment layer or the high refractive index layer. From the viewpoint of such effects, the component is preferably contained in the acrylic resin in an amount of 10 to 50 mol%, more preferably 20 to 40 mol%, and even more preferably 25 to 35 mol%. .
Examples of the monomer having a polyalkylene oxide chain include those obtained by adding polyalkylene oxide to an ester part of acrylic acid or methacrylic acid. Examples of the polyalkylene oxide chain include polymethylene oxide, polyethylene oxide, polypropylene oxide, and polybutylene oxide.
By using an acrylic resin having a polyalkylene oxide chain, the compatibility between the polyester resin and the acrylic resin in the first easy-adhesion layer is improved as compared with an acrylic resin not containing a polyalkylene oxide chain. The transparency of the layer can be improved. From such a viewpoint, it is preferable to contain 2 to 20 mol% of this component in the acrylic resin, and more preferably 5 to 15 mol%.
The repeating unit of the polyalkylene oxide chain is preferably 3 to 100, more preferably 4 to 50, still more preferably 5 to 20. If the number of repeating units of the polyalkylene oxide chain is too small, the compatibility between the polyester resin and the acrylic resin tends to be poor, and the effect of improving the transparency of the first easy-adhesion layer tends to be low. On the other hand, if it is too large, the heat-and-moisture resistance of the first easy-adhesion layer tends to be low, and particularly the adhesiveness to the optical adjustment layer or the high refractive index layer tends to be low under high humidity and high temperature.
As the remaining monomer constituting the acrylic resin as the crosslinking agent, alkyl acrylate (preferably methyl acrylate or ethyl acrylate) or alkyl methacrylate (preferably methyl methacrylate or ethyl methacrylate) may be used.
The content of the cross-linking agent in the first easy-adhesive layer is preferably 1 to 20% by mass, more preferably 2 to 15% with respect to 100% by mass of the total amount of the polyester resin and the cross-linking agent in the first easy-adhesive layer. % By mass, more preferably 8 to 15% by mass.
In this invention, the crosslinkable addition polymer which is a preferable crosslinking agent in the 2nd easily bonding layer mentioned later can be used as a crosslinking agent of a 1st easily bonding layer. Thereby, the effect similar to the effect which employ | adopts a crosslinkable addition polymer in a 2nd easily bonding layer can be provided to a 1st easily bonding layer.
<Optical adjustment layer>
An optical adjustment layer is provided on the first easy-adhesion layer.
The optical adjustment layer is a layer that has a function of suppressing the appearance of bone by matching the light reflection and transmission characteristics of the portion where the transparent conductive layer is present and the portion where the transparent conductive layer is not present due to the interference effect. The optical adjustment layer is usually composed of at least one high refractive index layer and at least one low refractive index layer, which are appropriately combined. Each of the high refractive index layer and the low refractive index layer may have a plurality of layers. Usually, it becomes a lamination order of a polyester film, a high refractive index layer, and a low refractive index layer. As the optical adjustment layer in the present invention, a high refractive index layer / low refractive index layer comprising a high refractive index layer on the side close to the polyester film and a low refractive index layer on the opposite side of the polyester film of the high refractive index layer. An embodiment having a two-layer structure is preferable.
(High refractive index layer)
The high refractive index layer is a layer having a refractive index of 1.60 to 1.80. By setting it as such a refractive index range, it is excellent by the bone appearance suppression effect by interaction with the other layer in this invention. If the refractive index is too high or too low, the effect of suppressing bone appearance tends to be low. From such a viewpoint, the refractive index of the high refractive index layer is preferably 1.60 or more, more preferably 1.62 or more, still more preferably 1.64 or more, and preferably 1.75 or less, more preferably 1.70 or less, more preferably 1.68 or less, particularly preferably 1.66 or less.
The high refractive index layer is preferably a layer comprising a metal and / or metal oxide and optionally a binder resin. Especially, it is preferable that it is a layer which consists of a metal oxide and binder resin. An example of such a metal oxide is a metal oxide film obtained by a sol-gel method. In this case, the metal oxide film can be a high refractive index layer. The metal oxide film may optionally contain a binder resin. Examples of the metal oxide include metal oxide fine particles. In this case, the metal oxide particles may include an embodiment in which the metal oxide particles are dispersed in the metal oxide film formed by the sol-gel method described above, or an embodiment in which the metal oxide particles are dispersed in the binder resin.
In the above, the type of metal oxide forming the film and fine particles in the high refractive index layer is not particularly limited as long as the above refractive index is satisfied, but the strength of the obtained film can be increased. From the viewpoint of being able to have an appropriate refractive index, it should be at least one selected from the group consisting of titanium oxide, zinc oxide, cerium oxide, zirconium oxide, indium-containing tin oxide, antimony-containing tin oxide and zinc antimonate. preferable. Among these, titanium oxide, antimony-containing tin oxide, and zirconium oxide are particularly preferable from the viewpoints of particularly high film strength and excellent dispersibility in the case of fine particles. These metal oxides may be used alone or in combination of two or more. That is, the metal oxide film which consists of 2 or more types of metal oxides may be sufficient, and the aspect containing 2 or more types of metal oxide fine particles may be sufficient. In the embodiment in which metal oxide fine particles are contained in the metal oxide film, the metal oxide forming the film and the metal oxide forming the fine particles may be the same or different. Good.
Examples of the binder resin in the high refractive index layer include acrylic resins, urethane resins, melamine resins, alkyd resins, siloxane polymers, and organic silane condensates. Among them, those having a skeleton that has a high refractive index may be preferably used. From the viewpoint of film strength, the binder resin is preferably formed by curing with heat, ultraviolet rays, electron beams or the like. Adhesiveness can be further improved by the binder resin.
A particularly preferable embodiment of the high refractive index layer in the present invention is an embodiment in which a binder resin is contained in the metal oxide film, and an organosilane condensate is particularly preferably contained in the titanium oxide film. It is an aspect.
Commercially available products can also be used as metal oxides preferably used for the high refractive index layer. For example, zirconium oxide: HXU-110JC (manufactured by Sumitomo Osaka Cement Co., Ltd.), titanium oxide: nanotech Ti-Tolu (Ci Kasei), zinc oxide: nanotech ZnO-Xylene (Ci Kasei), cerium oxide: Nidral (Taki Chemical) Indium-containing tin oxide: products manufactured by Mitsubishi Materials, antimony-containing tin oxide: SN-100D (manufactured by Ishihara Sangyo Co., Ltd.), zinc antimonate: Cellnax series (manufactured by Nissan Chemical Industries, Ltd.), etc. .
(Low refractive index layer)
The low refractive index layer is a layer having a refractive index of 1.40 to 1.60. By setting it as such a refractive index range, it is excellent by the bone appearance suppression effect by interaction with the other layer in this invention. If the refractive index is too high or too low, the bone appearance suppression effect tends to be low. From this viewpoint, the refractive index of the low refractive index layer is preferably 1.42 or more, more preferably 1.43 or more, further preferably 1.44 or more, and preferably 1.55 or less, more preferably 1.50 or less, more preferably 1.48 or less.
The low refractive index layer is not particularly limited as long as it satisfies the above refractive index, and may be a layer made of a binder resin, a layer made of a metal oxide, or a binder resin and a metal. It may be a layer made of an oxide. In addition, organic particles having a low refractive index can be contained. An example of the metal oxide is a metal oxide film obtained by a sol-gel method. In this case, the metal oxide film can be a low refractive index layer. The metal oxide film may optionally contain a binder resin. Examples of the metal oxide include metal oxide fine particles. In this case, the metal oxide particles may include an embodiment in which the metal oxide particles are dispersed in the metal oxide film formed by the sol-gel method described above, or an embodiment in which the metal oxide particles are dispersed in the binder resin.
In the above, the kind of metal oxide forming the film and fine particles in the low refractive index layer is particularly preferably silica from the viewpoint of forming a layer having a suitable low refractive index. Moreover, a more preferable low refractive index can be obtained by containing organic silane-based silicon compounds and low refractive index organic particles such as fluorine compounds as organic particles. Further, the refractive index can be lowered by forming voids by including a void forming agent in the layer.
Examples of the binder resin in the low refractive index layer include acrylic resins, urethane resins, melamine resins, alkyd resins, siloxane polymers, and organic silane condensates. Among them, those having a skeleton that has a low refractive index may be preferably used. From the viewpoint of film strength, the binder resin is preferably formed by curing with heat, ultraviolet rays, electron beams or the like.
A particularly preferable embodiment of the low refractive index layer in the present invention is an embodiment comprising a metal oxide film, and a silica film formed by a sol-gel method is particularly preferable.
In the present invention, by providing the high refractive index layer and the low refractive index layer as described above in the above-described arrangement, bone appearance is suppressed due to a synergistic effect with the other layers in the present invention.
In addition, when the refractive index of the high refractive index layer is within the above range, the thickness is preferably 50 to 250 nm, more preferably 100 to 200 nm, and even more preferably 125 to 175 nm. Can be high. In addition, when the refractive index of the low refractive index layer is within the above range, the thickness is preferably 5 to 50 nm, more preferably 10 to 45 nm, and even more preferably 20 to 40 nm. Can be high. Furthermore, the improvement effect of bone appearance suppression can be further heightened by making the thickness of each layer into the said preferable range simultaneously.
<Other layers>
The laminated body of this invention may have another layer in the range which does not inhibit the objective of this invention. For example, you may have the adhesion layer for bonding with another optical member in the surface on the opposite side to the optical adjustment layer of a polyester film. Further, a smoothing layer such as a hard coat layer may be provided on the first easy-adhesion layer, and an optical adjustment layer may be provided thereon. In this case, the smoothing layer exhibits suitable adhesiveness for both the first easy-adhesion layer and the optical adjustment layer (or the high refractive index layer) in the present invention. By doing so, the adhesiveness of a polyester film and an optical adjustment layer (or high refractive index layer) can be ensured as a result.
<Second easy adhesion layer>
In this invention, it can have a 2nd easily bonding layer in the surface on the opposite side to the 1st easily bonding layer of a polyester film. The second easy-adhesion layer is a layer for improving the adhesion between the polyester film and the functional layer when a functional layer such as a hard coat layer is laminated.
The second easy-adhesion layer is 70% by mass or more based on the weight of the second easy-adhesion layer, preferably 80% by mass or more, more preferably 85% by mass or more, and particularly preferably 90% by mass or more. It is a layer to contain. When the ratio of the copolyester resin is 70% by mass or more, the adhesion with a functional layer such as a hard coat layer is improved, and the refractive index of the second easy-adhesion layer can be within an appropriate range. Therefore, light interference spots can be suppressed. Furthermore, the glass transition temperature (Tg) of the second easy-adhesive layer is also in an appropriate range, and the film-forming property is improved, and the cracks of the second easy-adhesive layer are reduced, and the deterioration of the adhesiveness due to such cracks is suppressed. It can be excellent in adhesion.
The average refractive index in the plane direction of the oriented polyethylene terephthalate film is usually about 1.66, and the refractive index of the acrylic resin hard coat layer usually used as the functional layer is about 1.52. The refractive index is preferably in the range of 1.57 to 1.62, more preferably in the range of 1.58 to 1.61, and particularly preferably in the range of 1.59 to 1.60. Such a refractive index can be easily achieved by employing a copolyester resin described later.
The thickness of the second easy-adhesion layer is preferably 50 to 100 nm, more preferably 70 to 90 nm. By setting the thickness within this range, when a functional layer such as an acrylic hard coat layer is provided thereon, the effect of suppressing light interference spots is further increased, which is preferable.
(Copolymerized polyester resin for the second easy adhesion layer)
The copolymer polyester resin used for the second easy-adhesion layer can be selected from the modes described below depending on the intended effect. Such a copolyester resin can also be used as the polyester resin of the first easy-adhesion layer as long as the purpose is not hindered, whereby the effect of adopting such a copolyester resin is applied to the first easy-adhesion layer. Can be granted. Hereinafter, the first easy-adhesion layer and the second easy-adhesion layer may be collectively referred to as an easy-adhesion layer.
<Preferred embodiment 1 of copolymerized polyester resin (copolymerized polyester resin 1)>
In forming a coating layer such as the first and second easy-adhesion layers, a so-called in-line coating method in which orientation crystallization is completed after coating a coating liquid for forming a coating layer on a polyester film before completion of orientation is applied. Often used. However, according to our study, when applied on a polyethylene terephthalate film, it is presumed to be due to the cracking of the coating layer that occurs in the stretching process, but there may be cases where further improvement in adhesion is desired. found.
This aspect is a particularly suitable copolymer polyester resin for the purpose of excellent adhesion to a functional layer such as a hard coat layer and suppression of light interference spots (color spots) after the formation of the functional layer. It is an aspect.
The copolymerized polyester resin used in the second easy-adhesion layer of this embodiment has a naphthalenedicarboxylic acid component of 60 to 90 mol% and a carbon number of 6 to 6 on the basis of the total dicarboxylic acid component (100 mol%) of the copolymerized polyester. A copolymer comprising 12 alkylene dicarboxylic acid components and 4 to 10 alkylene glycol components in a total amount of 15 to 50 mol%, and a glycol component having a fluorene structure represented by the formula (I) of 5 mol% or more and less than 20 mol%. Polyester.
When the proportion of the naphthalenedicarboxylic acid component is in the above range, the refractive index of the copolyester can be increased, the refractive index of the second easy-adhesion layer can be easily set to the above-mentioned preferable range, Interference spots can be suppressed. Moreover, the swelling resistance of the second easily adhesive layer with respect to the solvent is also good. When the proportion of the naphthalenedicarboxylic acid component is less than the lower limit, the refractive index of the copolyester is lowered, and as a result, the refractive index of the second easy-adhesive layer is lowered and the effect of suppressing light interference spots is insufficient. Become. In addition, the swelling with organic solvents increases (solvent resistance deteriorates), so it swells when it comes into contact with the organic solvent in the coating liquid for functional layers such as the hard coat layer, resulting from the uneven thickness of the second easy-adhesive layer This is not preferable because it causes not only interference spots to occur but also blocking resistance. On the other hand, since the refractive index of the copolyester increases as the proportion of the naphthalenedicarboxylic acid component increases, the proportion of other components (for example, a crosslinking agent and other components described later) may be increased as the second easy-adhesion layer. it can. However, at the same time, the glass transition temperature (Tg) of the copolyester tends to be high and the glass transition temperature of the second easy-adhesion layer tends to be high. It tends to decrease. Accordingly, the preferable lower limit of the content of the naphthalenedicarboxylic acid component is 65 mol%, and the preferable upper limit is 85 mol%, more preferably 80 mol%, and particularly preferably 70 mol%. Here, examples of the naphthalenedicarboxylic acid component include 2,7-naphthalenedicarboxylic acid component, 2,6-naphthalenedicarboxylic acid component, 1,4-naphthalenedicarboxylic acid component, and the like, among which 2,6-naphthalenedicarboxylic acid component. Ingredients are preferred.
Further, based on the total acid component of the copolyester, it contains a total of 15 to 50 mol% of an alkylene dicarboxylic acid component having 6 to 12 carbon atoms and an alkylene glycol component having 4 to 10 carbon atoms. Preferably, the alkylene dicarboxylic acid component having 6 to 12 carbon atoms is contained in an amount of 0 to 40 mol% and the alkylene glycol component having 4 to 10 carbon atoms is contained in an amount of 0 to 50 mol%, and the alkylene dicarboxylic acid component and the alkylene glycol component are preferably contained. The total content is 15 to 50 mol%. For this reason, Tg of copolyester can be made low and Tg of a 2nd easily bonding layer can be made low. As a result, even the in-line coating method often adopted when forming the second easy-adhesion layer on the oriented polyethylene terephthalate film is excellent in the film-forming property of the second easy-adhesion layer. 2 It is possible to suppress the occurrence of cracking (cracking) in the easy-adhesion layer and to obtain a film having excellent adhesiveness. In particular, when the simultaneous biaxial stretching method is adopted for the production of the oriented polyester film and the in-line coating method is adopted for the formation of the second easy-adhesion layer, the preheating / drying temperature tends to be relatively low. The effect to employ | adopt is large especially preferable. Moreover, it is excellent also in blocking resistance.
If the total amount of the alkylene dicarboxylic acid component and the alkylene glycol component is less than the lower limit, the Tg of the copolyester will not be lowered sufficiently, resulting in insufficient adhesion. On the other hand, when the above-mentioned alkylene dicarboxylic acid component or alkylene glycol component exceeds the upper limit or the total of both exceeds the upper limit, not only the blocking resistance is lowered, but the content of other copolymer components is reduced. As a result, the refractive index of the copolyester becomes low and the effect of suppressing light interference spots becomes insufficient. Moreover, there exists a possibility that the solvent resistance of a 2nd easily bonding layer may fall. From such a viewpoint, the total amount of the alkylene dicarboxylic acid component and the alkylene glycol component is preferably in the range of 20 to 50 mol%.
Preferred examples of the alkylene dicarboxylic acid component having 6 to 12 carbon atoms (dicarboxylic acid component having an alkylene group having 4 to 10 carbon atoms) include 1,4-butanedicarboxylic acid component, 1,6-hexanedicarboxylic acid component, Examples thereof include 1,4-cyclohexanedicarboxylic acid component, 1,8-octanedicarboxylic acid component, 1,10-decanedicarboxylic acid component, and the like. Of these, a dicarboxylic acid component having an alkylene group having 4 to 8 carbon atoms is preferable, and a dicarboxylic acid component having an alkylene group having 4 to 6 carbon atoms is more preferable from the viewpoint that appropriate Tg is easily obtained. Examples of the alkylene glycol component having 4 to 10 carbon atoms preferably used include a 1,4-butanediol component, a 1,6-hexanediol component, a 1,4-cyclohexanediol component, a 1,8-octanediol component, Examples include 1,10-decanediol component. Among these, an alkylene glycol component having 4 to 8 carbon atoms is preferable, and an alkylene glycol component having 4 to 6 carbon atoms is more preferable from the viewpoint that appropriate Tg can be easily obtained.
In addition, when it is intended to add another copolymer component to the copolymer polyester to impart other functions, it is easier to add it as an acid component, and it is also easy to carry out a polymerization reaction. From the viewpoint of leaving room, it is more preferable to contain the alkylene dicarboxylic acid component and the alkylene glycol component as an alkylene glycol component.
Further, since the glycol component having the fluorene structure represented by the formula (I) is contained in an amount of 5 mol% or more and less than 20 mol% based on the total acid component of the copolymerized polyester, the Tg of the copolymerized polyester is appropriately low. While maintaining the temperature, the refractive index can be increased to a preferable range. When the content of the glycol component having the fluorene structure represented by the formula (I) is less than 5 mol%, it is difficult to make the refractive index of the copolymer polyester within a preferable range, and light interference spots cannot be suppressed. . On the other hand, in the case of 20 mol% or more, since the Tg of the copolyester becomes too high, not only the film-forming property of the second easy-adhesive layer is lowered and the transparency of the resulting film is lowered, but also the adhesiveness. Also decreases. From such a viewpoint, the preferred lower limit is 3 mol%, more preferably 5%, and the preferred upper limit is 15 mol%, more preferably 10%. Examples of the glycol component having a fluorene structure represented by the formula (I) preferably used include a 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene component and a 9,9-bis [4- (2 -Hydroxyethoxy) -2-methylphenyl] fluorene component.
The copolymerized polyester of the second easy-adhesion layer in this embodiment described above contains 5 to 25 mol%, more preferably 10 to 20 mol%, of an ethylene oxide adduct component of bisphenol A in addition to the above components. It is preferable that Tg can be within a more preferable range while maintaining the refractive index, and the adhesiveness is also improved. The average added mole number of ethylene oxide is suitably in the range of 2 to 4 moles with respect to 1 mole of bisphenol A.
In addition to the above components, in order to keep the Tg of the copolyester within a more preferable range while maintaining the refractive index, terephthalic acid and / or isophthalic acid is contained in an amount of 20 to 40 mol%, particularly 24 to 34 mol%. It is preferable to contain. Among these, an isophthalic acid component is preferable because it is easy to obtain a more suitable Tg.
Further, the copolyester of this embodiment preferably contains 1 to 10 mol% of a dicarboxylic acid component having a sulfonate group based on the total acid component. Thereby, the solubility at the time of making copolymer polyester into aqueous coating liquid thru | or water dispersibility can be improved. Moreover, the solvent resistance (swelling resistance) of the second easy-adhesion layer can be improved. However, if the amount is too large, the water resistance and blocking resistance of the second easy-adhesion layer tend to be low, so the range of 2 to 8 mol% is particularly preferable. Examples of the aromatic dicarboxylic acid component having a sulfonate group include a 5-sodium sulfoisophthalic acid component, a 5-potassium sulfoisophthalic acid component, a 5-lithium sulfoisophthalic acid component, and a 5-phosphonium sulfoisophthalic acid component. However, the 5-sodium sulfoisophthalic acid component is most preferable from the viewpoint of improving water dispersibility.
The following can be illustrated as a specific aspect of the copolyester resin 1 preferably used.
[Preferred embodiment 1 of copolyester resin 1 (preferred embodiment 1-1)]
(A2) Naphthalene dicarboxylic acid component is 60 to 90 mol%
(B2) 0 to 40 mol% of the alkylene dicarboxylic acid component having 6 to 12 carbon atoms, 0 to 50 mol% of the alkylene glycol component having 4 to 10 carbon atoms, and the total of the alkylene dicarboxylic acid component and the alkylene glycol component being 15 ~ 50 mol%
(C2) 5 mol% or more and less than 20 mol% of the glycol component having a fluorene structure represented by the formula (I), and
(D2) 5-25 mol% of bisphenol A ethylene oxide adduct component
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
Copolyester containing.
[Preferred Embodiment 2 of Copolyester Resin 1 (Preferred Embodiment 1-2)]
(A3) Naphthalene dicarboxylic acid component is 60 to 80 mol%
(B3) 15 to 50 mol% of an alkylene glycol component having 4 to 10 carbon atoms
(C3) 5 mol% or more and less than 20 mol% of the glycol component having the fluorene structure represented by the formula (I)
(D3) 5-25 mol% of bisphenol A ethylene oxide adduct component
(E3) 20-40 mol% of terephthalic acid component and / or isophthalic acid component
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
Copolyester containing.
[Preferred Aspect 3 (Preferred Aspect 1-3) of Copolyester Resin 1]
(A4) Naphthalene dicarboxylic acid component is 60 to 80 mol%
(B4) 15 to 50 mol% of an alkylene glycol component having 4 to 10 carbon atoms
(C4) 5 mol% or more and less than 20 mol% of the glycol component having the fluorene structure represented by the formula (I)
(E4) 20-40 mol% of terephthalic acid component and / or isophthalic acid component
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
Copolyester containing.
[Preferred Embodiment 4 of Copolyester Resin 1 (Preferred Embodiment 1-4)]
(A5) Naphthalenedicarboxylic acid component is 60 to 70 mol%
(B5) 15 to 50 mol% of an alkylene glycol component having 4 to 10 carbon atoms
(C5) 5 mol% or more and less than 20 mol% of the glycol component having the fluorene structure represented by the formula (I)
(D5) 5-25 mol% of bisphenol A ethylene oxide adduct component
(E5) 24 to 34 mol% of terephthalic acid component and / or isophthalic acid component
(F5) 6-8 mol% of dicarboxylic acid component having a sulfonate group
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
Copolyester containing.
(Polyester film)
In this embodiment, the polyester film is preferably an oriented polyethylene terephthalate film, which may be a uniaxially oriented film or a biaxially oriented film, but the in-plane mechanical and thermal properties are uniform. From this point, a biaxially oriented film is preferable. At that time, the average refractive index in the plane direction (in the film plane, the average refractive index between the refractive index in any one direction and the refractive index in the direction perpendicular thereto) is provided on the second easy-adhesive layer of this aspect. When a functional layer such as a hard coat layer is provided, the range of 1.6 to 1.7 is preferable from the viewpoint of suppressing the occurrence of light interference spots (color spots).
The second easy-adhesion layer of this aspect is, for example, the first easy-adhesion layer when the main purpose is excellent adhesion to a functional layer such as a hard coat layer and suppression of light interference spots after the functional layer is formed. The second easy-adhesion layer can be provided on one or both sides of the polyester film to form a laminated polyester film. Such a laminated polyester film includes the following embodiments.
1. A laminated polyester film having a second easy-adhesion layer on at least one surface of an oriented polyethylene terephthalate film, wherein the second easy-adhesion layer comprises 70% by mass or more of the following copolyester based on the mass of the second easy-adhesion layer. Contains laminated polyester film.
Copolyester:
(A1) 60-90 mol% of naphthalenedicarboxylic acid component,
(B1) 0 to 40 mol% of the alkylene dicarboxylic acid component having 6 to 12 carbon atoms, 0 to 50 mol% of the alkylene glycol component having 4 to 10 carbon atoms, and the total of the alkylene dicarboxylic acid component and the alkylene glycol component is 15 ~ 50 mol%, and
(C1) A copolyester containing a glycol component having a fluorene structure represented by the formula (I) in an amount of 5 mol% to less than 20 mol%.
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
2. The copolyester is further
(D2) 5-25 mol% of bisphenol A ethylene oxide adduct component
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
The laminated polyester film according to 1 above, comprising:
3. The copolymerized polyester is
(A3) The proportion containing a naphthalenedicarboxylic acid component is 60 to 80 mol%,
(B3) the proportion of the alkylene dicarboxylic acid component having 6 to 12 carbon atoms is 0 mol%,
(E3) containing 20 to 40 mol% of terephthalic acid and / or isophthalic acid component,
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
3. The laminated polyester film as described in 1 or 2 above.
4). 4. The laminated polyester film according to any one of 1 to 3 above, wherein the second easy-adhesive layer contains 1 to 30% by mass of a crosslinking agent based on the mass of the second easy-adhesive layer.
5. 5. The laminated polyester film as described in any one of 1 to 4 above, which is used as an easily adhesive polyester film for optics.
<Preferred embodiment 2 of copolymerized polyester resin (copolymerized polyester resin 2)>
Various solvents have come to be used as coating solutions for forming functional layers such as hard coat layers. Depending on the solvent, the easy-adhesion layer swells and dissolves, and the thickness varies, resulting in interference. There is a problem that the spots cannot be suppressed. In response to such a problem, for example, in JP 2009-300658 A and JP 2009-300658 A, by adding particles having a relatively large particle diameter of 0.2 to 0.7 μm in average particle diameter, A method has been proposed in which interference spots are suppressed by surface roughness even when the thickness of the easy-adhesion layer varies. Note that the problem related to the thickness variation may be a problem that the appearance of bones cannot be suppressed because various solvents are similarly used when forming the optical adjustment layer.
This aspect is a particularly suitable copolymer polyester resin for the purpose of excellent adhesion to a functional layer such as a hard coat layer and suppression of light interference spots (color spots) after the formation of the functional layer. It is an aspect.
Such a copolyester uses, for example, a component capable of increasing the refractive index such as a naphthalenedicarboxylic acid component or a glycol component having a fluorene structure and a component capable of adjusting the swelling ratio such as an aromatic dicarboxylic acid component having a sulfonate group. The refractive index and the swelling rate may be adjusted by adjusting the copolymerization amount.
Examples of the copolymer polyester preferably used include, for example, an aromatic dicarboxylic acid component having 60 to 90 mol% of a naphthalenedicarboxylic acid component and a sulfonate group based on the total dicarboxylic acid component (100 mol%) of the copolymer polyester. Examples thereof include those containing 1 to 10 mol% and 5 to 25 mol% of bisphenol A ethylene oxide adduct.
When the proportion of the naphthalenedicarboxylic acid component is in the above range, the refractive index of the copolyester can be increased, the refractive index of the second easy-adhesion layer can be easily set in the above range, and interference spots can be prevented. Can be suppressed. Further, the swelling ratio of the second easy-adhesion layer can be easily set within a preferable range. If the ratio of the naphthalenedicarboxylic acid component is too small, the refractive index of the copolyester is lowered, and as a result, the refractive index of the second easy-adhesive layer is lowered and the effect of suppressing interference spots is insufficient. On the other hand, since the refractive index of the copolyester increases as the proportion of the naphthalenedicarboxylic acid component increases, the proportion of other components (for example, a crosslinking agent and other components described later) may be increased as the second easy-adhesion layer. it can. However, at the same time, the glass transition temperature (Tg) of the copolyester tends to be high and the glass transition temperature of the second easy-adhesion layer tends to be high. The transparency of the film tends to decrease. Therefore, the content of the naphthalenedicarboxylic acid component is preferably 65 mol% or more, and 85 mol% or less, more preferably 80 mol% or less, and particularly preferably 70 mol% or less. Here, as a preferable naphthalene dicarboxylic acid component, it is the same as that of the copolyester resin 1.
Further, by having the aromatic dicarboxylic acid component having a sulfonate group in the above range based on the total acid component of the copolymer polyester, the solubility or water dispersibility when the copolymer polyester is used as an aqueous coating liquid is improved. be able to. In addition, the swelling ratio of the second easy-adhesion layer can be easily within a preferable range. However, if the amount is too large, the water resistance and blocking resistance of the second easy-adhesion layer tend to be low, so the content is preferably 2 to 8 mol%, particularly preferably 6 to 8 mol%. The aromatic dicarboxylic acid component having a preferred sulfonate group is the same as the copolymer polyester resin 1. .
Furthermore, by having the ethylene oxide adduct component of bisphenol A in the above range based on the total acid component of the copolymer polyester, the Tg can be made a preferred range while maintaining the refractive index of the copolymer polyester, The film forming property of the second easy-adhesion layer is improved, and a film excellent in transparency can be obtained. Moreover, it becomes easy to make a swelling rate into a preferable range. The average added mole number of ethylene oxide is suitably in the range of 2 to 4 moles with respect to 1 mole of bisphenol A.
The copolymer polyester described above preferably contains 5 mol% or more and less than 20 mol% of the glycol component having the fluorene structure represented by the formula (I) in addition to the above components. While maintaining Tg at a moderately low temperature, the refractive index can be within a preferred range. When the content of such components decreases, the refractive index of the copolyester tends to decrease, while when it increases, the Tg of the copolyester increases, and the film-forming property of the second easy-adhesive layer decreases and the transparency of the film is reduced. Tend to decrease, and the adhesiveness also tends to decrease. From such a viewpoint, the preferable lower limit is 5 mol%, and the preferable upper limit is 15 mol%, and particularly preferably 10 mol%. The glycol component having a fluorene structure represented by the formula (I) preferably used is the same as that of the copolyester resin 1.
Further, in addition to the above components, it is preferable to contain a total of 15 to 50 mol% of an alkylene dicarboxylic acid component having 6 to 12 carbon atoms and an alkylene glycol component having 4 to 10 carbon atoms. More preferably, it contains 0 to 40 mol% of the alkylene dicarboxylic acid component having 6 to 12 carbon atoms and 0 to 50 mol% of the alkylene glycol component having 4 to 10 carbon atoms, and the alkylene dicarboxylic acid component and the alkylene glycol In this embodiment, the total amount of the components is 15 to 50 mol%. Thereby, Tg of copolyester can be made low and Tg of a 2nd easily bonding layer can be made low. As a result, even if the polyester film is a polyethylene terephthalate film, even the in-line coating method often adopted when forming the second easy-adhesion layer is excellent in the film-forming property of the second easy-adhesion layer, so that the transparency is improved. An excellent film is obtained. In particular, when the simultaneous biaxial stretching method is used and the in-line coating method is used to form the second easy-adhesion layer, the preheating / drying temperature tends to be relatively low. Largely preferred. Moreover, the adhesive improvement effect can be enhanced and the blocking resistance is also excellent.
When the total amount of the alkylene dicarboxylic acid component and the alkylene glycol component decreases, the Tg of the copolyester is difficult to decrease, and the transparency of the resulting film may be reduced. On the other hand, when the amount of the alkylene dicarboxylic acid component or the alkylene glycol component is increased or the sum of both is increased, the anti-blocking property is reduced, or the refractive index of the copolyester is reduced and the effect of suppressing interference spots is reduced. There is a case. In addition, the swelling rate of the second easy-adhesion layer may increase. From such a viewpoint, the total amount of the alkylene dicarboxylic acid component and the alkylene glycol component is preferably in the range of 20 to 50 mol%.
The alkylene dicarboxylic acid component having 6 to 12 carbon atoms (dicarboxylic acid component having an alkylene group having 4 to 10 carbon atoms) and the alkylene glycol component having 4 to 10 carbon atoms that are preferably used include copolymer polyester resin 1 It is the same.
In addition, when other copolymerization components are added to the copolymerized polyester to impart other functions, the above-mentioned alkylene dicarboxylic acid component and the above-mentioned alkylene glycol can be easily added as an acid component and easily subjected to a polymerization reaction. Among the components, it is more preferable to contain them as an alkylene glycol component.
Further, in addition to the above components, in order to keep the Tg of the copolyester within a more preferable range while maintaining the refractive index, terephthalic acid and / or isophthalic acid is contained in an amount of 20 to 40 mol%, particularly 24 to 34 mol%. It is preferable to contain. Among these, an isophthalic acid component is preferable because it is easy to obtain a more suitable Tg.
The following can be illustrated as a specific aspect of the copolyester resin 2 preferably used.
[Preferred Embodiment 1 of Copolyester Resin 2 (Preferred Embodiment 2-1)]
(A) 60-90 mol% of naphthalenedicarboxylic acid component
(B) 1 to 10 mol% of an aromatic dicarboxylic acid component having a sulfonate group, and
(C) 5-25 mol% of bisphenol A ethylene oxide adduct component
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
Copolyester containing.
[Preferred Embodiment 2 of Copolyester Resin 2 (Preferred Embodiment 2-2)]
(A) 60-90 mol% of naphthalenedicarboxylic acid component
(B) 1-10 mol% of an aromatic dicarboxylic acid component having a sulfonate group
(C) 5 to 25 mol% of bisphenol A ethylene oxide adduct component, and
(D) 5 mol% or more and less than 20 mol% of the glycol component having the fluorene structure represented by the formula (I)
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
Copolyester containing.
[Preferred Embodiment 3 of Copolyester Resin 2 (Preferred Embodiment 2-3)]
(A) 60-90 mol% of naphthalenedicarboxylic acid component
(B) 1-10 mol% of an aromatic dicarboxylic acid component having a sulfonate group
(C) 5-25 mol% of bisphenol A ethylene oxide adduct component
(D) 5 mol% or more and less than 20 mol% of the glycol component having a fluorene structure represented by the formula (I), and
(E) 15 to 50 mol% of an alkylene glycol component having 4 to 10 carbon atoms
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
Copolyester containing.
[Preferred Embodiment 4 of Copolyester Resin 2 (Preferred Embodiment 2-4)]
(A) 60-70 mol% of naphthalene dicarboxylic acid component
(B) 6-8 mol% of an aromatic dicarboxylic acid component having a sulfonate group
(C) 5-25 mol% of bisphenol A ethylene oxide adduct component
(D) 5 mol% or more and less than 20 mol% of the glycol component having a fluorene structure represented by the formula (I), and
(F) 24 to 34 mol% of terephthalic acid component and / or isophthalic acid component
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
Copolyester containing.
[Preferred Aspect 5 (Preferred Aspect 2-5) of Copolyester Resin 2]
(A) 60-70 mol% of naphthalene dicarboxylic acid component
(B) 6-8 mol% of an aromatic dicarboxylic acid component having a sulfonate group
(C) 5-25 mol% of bisphenol A ethylene oxide adduct component
(D) 5 mol% or more and less than 20 mol% of the glycol component having the fluorene structure represented by the formula (I)
(E) 15 to 50 mol% of an alkylene glycol component having 4 to 10 carbon atoms, and
(F) 24 to 34 mol% of terephthalic acid component and / or isophthalic acid component
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
Copolyester containing.
It is preferable that the 2nd easily bonding layer in this aspect is the following aspects.
(Refractive index)
The refractive index of the second easy-adhesion layer in this embodiment is preferably 1.58 to 1.64. More preferably, it is 1.58 to 1.62, more preferably 1.58 to 1.60, and particularly preferably 1.58 to 1.59. When the refractive index of the second easy-adhesion layer is within this range, the average refractive index in the plane direction of a preferable polyester film, which will be described later, and the refractive index of a hard coat layer usually made of an acrylic resin (approximately 1.52) Since the refractive index is between, interference spots (color spots) when a hard coat layer made of such an acrylic resin is applied on the second easy-adhesion layer can be suppressed. If this refractive index is too high or too low, it becomes difficult to suppress interference spots. Moreover, it becomes easy to make a swelling rate into a preferable range by setting it as the 2nd easily bonding layer which consists of a component which becomes such a refractive index, Preferably the component mentioned above.
In order to achieve such a refractive index, the refractive index of each component constituting the second easy-adhesion layer may be adjusted. For example, the refractive index of a 2nd easily bonding layer can be made high by using copolyester resin and particle | grains with a high refractive index. Particularly preferably, the above-described copolymer polyester resin 2 may be employed.
(Thickness)
In this embodiment, the thickness of the second easy-adhesion layer needs to be 50 to 100 nm, and preferably 70 to 90 nm. By setting the thickness of the second easy-adhesion layer within this range, interference spots (color spots) when a low refractive index layer such as a hard coat layer made of an acrylic resin is provided thereon can be suppressed. If this thickness is too thin, the adhesiveness tends to decrease, and if it is too thin or too thick, it becomes difficult to suppress interference spots.
(Swell rate)
In the second easy-adhesion layer in this embodiment, the swelling ratio obtained by the following method is 130 to 200% in any of the following solvents. Preferably it is 130 to 180%, more preferably 135 to 175%, still more preferably 139 to 165%. Here, the swelling rate is determined by applying a coating solution (solid content concentration: 40% by mass) obtained by diluting the following UV curable composition with a solvent onto the second easy-adhesive layer of the film, drying and curing, and then hardening the hard 5 μm thick. From the thickness dh of the second easy-adhesion layer after forming the coat layer and forming the hard coat layer and the thickness d0 of the second easy-adhesion layer before forming the hard coat layer, the swelling ratio E (%) = dh / d0 × 100
It is the value calculated as. The following are used as the UV curable composition, and as the solvent, methyl ethyl ketone (MEK), ethyl acetate, toluene, isopropanol (IPA) and propylene, which are representative of the solvents usually used for forming hard coat layers and the like, are used. Glycol monomethyl ether acetate (PGMEA) is used, and in any of these solvents, the swelling ratio of the second easy-adhesion layer needs to be in the above range.
UV curable composition:
Pentaerythritol acrylate: 45% by mass
N-methylolacrylamide: 40% by mass
N-vinylpyrrolidone: 10% by mass
1-hydroxycyclohexyl phenyl ketone: 5% by mass
When the swelling ratio is less than 130%, the adhesion with the hard coat layer tends to be low. On the other hand, when the swelling ratio exceeds 200%, the functional layer such as the hard coat layer is formed before and after the formation. Since the variation in the thickness of the second easy-adhesion layer is too large, it is difficult to suppress interference spots. Further, it is important that the swelling rate is within the above range in any of the above solvents. If the swelling rate in any of the solvents is out of this range, such a solvent is used to form a hard coat layer or the like. This is because when the functional layer is formed, the adhesiveness is insufficient or it is difficult to suppress interference spots. In addition, since the swelling rate is easier to suppress interference spots when the hard coat layer is formed when the fluctuation due to the type of solvent is less, the difference between the maximum swelling rate and the minimum swelling rate is 50% or less. It is preferable that it is 25% or less.
In order to achieve such a swelling ratio, the components used for the second easy-adhesion layer, particularly the copolymer component constituting the binder component, may be adjusted to balance the lipophilicity and the hydrophilicity. Specifically, the above-described preferred embodiment of the copolyester resin 2 can be used. The swelling rate can also be adjusted by using a crosslinking agent for the second easy-adhesion layer. The crosslinking agent tends to have a lower swelling ratio as the addition amount increases.
(Polyester film)
The preferred polyester film according to this embodiment has a refractive index in the plane direction (average refractive index of a refractive index in any one direction and a refractive index in a direction perpendicular thereto in the film plane) of 1.63 to 1.68. Preferably, it is in the range of 1.64 to 1.67, particularly preferably 1.65 to 1.66. When the refractive index in the plane direction is in this range, the film provided with the second easy-adhesion layer using the above-described copolymer polyester resin 2 has a low refractive index layer such as a hard coat layer formed thereon. Excellent in suppressing the occurrence of interference spots. Even if the surface direction refractive index is out of the above range and is too high or too low, the effect of suppressing the occurrence of interference spots tends to decrease.
Such a polyester film may be any of an unoriented film, a uniaxially oriented film, and a biaxially oriented film as long as the plane direction refractive index satisfies the above requirements. To a biaxially oriented film.
The second easy-adhesion layer of this aspect is, for example, the first easy-adhesion layer when the main purpose is excellent adhesion to a functional layer such as a hard coat layer and suppression of light interference spots after the functional layer is formed. The second easy-adhesion layer can be provided on one or both sides of the polyester film to form a laminated polyester film. Such a laminated polyester film includes the following embodiments.
1. At least one surface of a polyester film having a surface direction refractive index of 1.63 to 1.68 has a refractive index of 1.58 to 1.64, and the swelling ratio required by the following method is 130 to 200% in any solvent, A laminated polyester film having a second easy adhesion layer having a thickness of 50 to 100 nm.
Swelling rate:
On the second easy-adhesion layer of the laminated polyester film, a coating solution (solid content concentration 40% by mass) obtained by diluting the following UV curable composition with a solvent (methyl ethyl ketone, ethyl acetate, toluene, isopropanol or propylene glycol monomethyl ether) is applied. And then drying and curing to form a hard coat layer having a thickness of 5 μm, the thickness dh of the second easy-adhesion layer after forming the hard coat layer, and the thickness of the second easy-adhesion layer before forming the hard coat layer The value obtained from d0 as the swelling ratio E (%) = dh / d0 × 100.
UV curable composition:
Pentaerythritol acrylate: 45% by mass
N-methylolacrylamide: 40% by mass
N-vinylpyrrolidone: 10% by mass
1-hydroxycyclohexyl phenyl ketone: 5% by mass
2. 2. The laminated polyester film according to 1 above, wherein the second easy-adhesion layer contains 70% by mass or more of the following copolyester based on the mass of the second easy-adhesion layer.
Copolyester:
(A2) Naphthalenedicarboxylic acid component is 60 to 90 mol%,
(B2) 1 to 10 mol% of an aromatic dicarboxylic acid component having a sulfonate group, and
(C2) Copolyester containing 5 to 25 mol% of bisphenol A ethylene oxide adduct component.
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
3. The copolyester is further
(D3) 5 mol% or more and less than 20 mol% of the glycol component having the fluorene structure represented by the formula (I)
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
3. The laminated film as described in 2 above.
4). 4. The laminated polyester film as described in 2 or 3 above, wherein the second easy-adhesive layer contains 1 to 30% by mass of a crosslinking agent based on the mass of the second easy-adhesive layer.
5. 5. The laminated polyester film as described in any one of 1 to 4 above, which is used as an easily adhesive polyester film for optics.
<Preferred embodiment 3 of copolymerized polyester resin (copolymerized polyester resin 3)>
In forming a coating layer such as the first and second easy-adhesion layers, a so-called in-line coating method in which orientation crystallization is completed after coating a coating liquid for forming a coating layer on a polyester film before completion of orientation is applied. Often used. However, according to our study, when applied on a polyethylene terephthalate film, it is presumed to be due to the cracking of the coating layer that occurs in the stretching process, but there may be cases where further improvement in adhesion is desired. found. And about this adhesiveness, the improvement of the adhesiveness (wet heat adhesiveness) especially in a wet heat environment is strongly requested | required.
This aspect is particularly suitable for the purpose of, for example, excellent adhesion with a functional layer such as a hard coat layer in a humid heat environment, and suppression of light interference spots (color spots) after the formation of the functional layer. This is an embodiment of a polymerized polyester resin.
The copolymerized polyester resin used in the second easy-adhesion layer of this embodiment has a naphthalenedicarboxylic acid component of 60 to 90 mol% and a carbon number of 6 to 6 on the basis of the total dicarboxylic acid component (100 mol%) of the copolymerized polyester. 12 alkylene dicarboxylic acid components and alkylene glycol components having 4 to 10 carbon atoms in total 15 to 50 mol%, glycol components having a fluorene structure represented by the formula (I) of 5 mol% or more and less than 20 mol%, and It contains 0.1 to 5 mol% of a dicarboxylic acid component having a sulfonate group.
The preferred embodiment and effect of the naphthalenedicarboxylic acid component are the same as those of the copolyester resin 1. In this embodiment, considering that the dicarboxylic acid component having a sulfonate group is an essential component, the preferable lower limit of the content of the naphthalene dicarboxylic acid component is 65 mol%, and the preferable upper limit is 85. The mol%, more preferably 80 mol%, still more preferably 75.9 mol%, particularly preferably 70 mol%.
Further, based on the total acid component of the copolyester, it contains a total of 15 to 50 mol% of an alkylene dicarboxylic acid component having 6 to 12 carbon atoms and an alkylene glycol component having 4 to 10 carbon atoms. Preferred embodiments and effects of such components are the same as those of the copolyester resin 1. In this embodiment, considering that the dicarboxylic acid component having a sulfonate group is an essential component, the content is preferably 0 to 39.9 mol% of the alkylene dicarboxylic acid component having 6 to 12 carbon atoms. And an alkylene glycol component having 4 to 10 carbon atoms is contained in an amount of 0 to 50 mol%, and the total of the alkylene dicarboxylic acid component and the alkylene glycol component is 15 to 50 mol%. .
Moreover, 5 mol% or more and less than 20 mol% of the glycol component which has the fluorene structure shown by said Formula (I) is included on the basis of all the acid components of copolyester. Preferred embodiments and effects of such components are the same as those of the copolyester resin 1.
Furthermore, in this embodiment, the content of the dicarboxylic acid component having a sulfonate group is 0.1 to 5 mol% based on the total acid component. Thereby, the adhesiveness in a wet heat environment can be made high. If the amount is too large, the adhesiveness in a moist heat environment tends to be low, and the range of 0.1 to 4.5 mol% is particularly preferable. On the other hand, even if the content is too small, the effect of dispersing or dissolving in a solvent (particularly an aqueous solvent) tends to be reduced, and uniform coating tends to be difficult. Adhesiveness tends to be low. From this viewpoint, 0.2 mol% or more is preferable, and 0.4 mol% or more is more preferable. The aromatic dicarboxylic acid component having a preferred sulfonate group is the same as the copolymer polyester resin 1.
The copolymerized polyester of the second easy-adhesion layer in this embodiment described above contains 5 to 25 mol%, more preferably 10 to 20 mol%, of an ethylene oxide adduct component of bisphenol A in addition to the above components. Preferably it is. Preferred embodiments and effects of such components are the same as those of the copolyester resin 1.
In addition to the above components, in order to keep the Tg of the copolyester in a more preferable range while maintaining the refractive index, 20 to 39.9 mol%, particularly 24 to 34, of terephthalic acid and / or isophthalic acid is used. It is preferable to contain mol%. Among these, an isophthalic acid component is preferable because it is easy to obtain a more suitable Tg.
The following can be illustrated as a specific aspect of the copolyester resin 3 preferably used.
[Preferred Embodiment 1 of Copolyester Resin 3 (Preferred Embodiment 3-1)]
(A2) Naphthalene dicarboxylic acid component is 60 to 90 mol%
(B2) 0 to 39.9 mol% of the alkylene dicarboxylic acid component having 6 to 12 carbon atoms, 0 to 50 mol% of the alkylene glycol component having 4 to 10 carbon atoms, and the total of the alkylene dicarboxylic acid component and the alkylene glycol component 15 to 50 mol%
(C2) 5 mol% or more and less than 20 mol% of the glycol component having a fluorene structure represented by the formula (I)
(D2) 5-25 mol% of bisphenol A ethylene oxide adduct component
(F2) 0.1-5 mol% of dicarboxylic acid component having sulfonate group
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
Copolyester containing.
[Preferred Aspect 2 (Preferred Aspect 3-2) of Copolyester Resin 3]
(A3) Naphthalene dicarboxylic acid component is 60 to 80 mol%
(B3) 15 to 50 mol% of an alkylene glycol component having 4 to 10 carbon atoms
(C3) 5 mol% or more and less than 20 mol% of the glycol component having the fluorene structure represented by the formula (I)
(D3) 5-25 mol% of bisphenol A ethylene oxide adduct component
(E3) 20 to 39.9 mol% of terephthalic acid component and / or isophthalic acid component
(F3) 0.1-5 mol% of dicarboxylic acid component having a sulfonate group
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
Copolyester containing.
[Preferred Embodiment 3 of Copolyester Resin 3 (Preferred Embodiment 3-3)]
(A4) Naphthalene dicarboxylic acid component is 60 to 80 mol%
(B4) 15 to 50 mol% of an alkylene glycol component having 4 to 10 carbon atoms
(C4) 5 mol% or more and less than 20 mol% of the glycol component having the fluorene structure represented by the formula (I)
(E4) 20 to 39.9 mol% of terephthalic acid component and / or isophthalic acid component
(F4) 0.1-5 mol% of dicarboxylic acid component having a sulfonate group
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
Copolyester containing.
[Preferred Embodiment 4 of Copolyester Resin 3 (Preferred Embodiment 3-4)]
(A5) Naphthalene dicarboxylic acid component is 60 to 75.9 mol%
(B5) 15 to 50 mol% of an alkylene glycol component having 4 to 10 carbon atoms
(C5) 5 mol% or more and less than 20 mol% of the glycol component having the fluorene structure represented by the formula (I)
(D5) 5-25 mol% of bisphenol A ethylene oxide adduct component
(E5) 20 to 39.9 mol% of terephthalic acid component and / or isophthalic acid component
(F5) 0.1-5 mol% of dicarboxylic acid component having a sulfonate group
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
Copolyester containing.
(Polyester film)
In this embodiment, the polyester film is preferably an oriented polyethylene terephthalate film, which may be a uniaxially oriented film or a biaxially oriented film, but the in-plane mechanical and thermal properties are uniform. From this point, a biaxially oriented film is preferable. At that time, the average refractive index in the plane direction (in the film plane, the average refractive index between the refractive index in any one direction and the refractive index in the direction perpendicular thereto) is provided on the second easy-adhesive layer of this aspect. When a functional layer such as a hard coat layer is provided, the range of 1.6 to 1.7 is preferable from the viewpoint of suppressing the occurrence of light interference spots (color spots).
The second easy-adhesion layer of this aspect is, for example, excellent adhesiveness with a functional layer such as a hard coat layer in a moist heat environment and the suppression of light interference spots after the formation of the functional layer. A 2nd easily bonding layer can be provided in the one or both surfaces of a polyester film, without having 1 easily bonding layer, and it can be set as a laminated polyester film. Such a laminated polyester film includes the following embodiments.
1. A laminated polyester film having a second easy-adhesion layer on at least one surface of an oriented polyethylene terephthalate film, wherein the second easy-adhesion layer comprises 70% by mass or more of the following copolyester based on the mass of the second easy-adhesion layer. Contains laminated polyester film.
Copolyester:
(A1) 60-90 mol% of naphthalenedicarboxylic acid component,
(B1) 15 to 50 mol% of the total of alkylene dicarboxylic acid component having 6 to 12 carbon atoms and alkylene glycol component having 4 to 10 carbon atoms,
(C1) 5 mol% or more and less than 20 mol% of the glycol component having a fluorene structure represented by the formula (I), and
(F1) Copolyester containing 0.1 to 5 mol% of a dicarboxylic acid component having a sulfonate group.
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
2. The copolyester is further
(D2) 5-25 mol% of bisphenol A ethylene oxide adduct component
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
The laminated polyester film according to 1 above, comprising:
3. The copolymerized polyester is
(A3) The proportion containing a naphthalenedicarboxylic acid component is 60 to 80 mol%,
(B3) the proportion of the alkylene dicarboxylic acid component having 6 to 12 carbon atoms is 0 mol%,
(E3) containing 20 to 39.9 mol% of terephthalic acid and / or isophthalic acid component,
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
3. The laminated polyester film as described in 1 or 2 above.
4). 4. The laminated polyester film according to any one of 1 to 3 above, wherein the second easy-adhesive layer contains 1 to 30% by mass of a crosslinking agent based on the mass of the second easy-adhesive layer.
5. 5. The laminated polyester film as described in any one of 1 to 4 above, which is used as an easily adhesive polyester film for optics.
The copolyester detailed above can be produced by a conventionally known polyester production technique. For example, an acid component such as 2,6-naphthalenedicarboxylic acid or an ester-forming derivative thereof, isophthalic acid or an ester-forming derivative thereof and 5-sodium sulfoisophthalic acid or an ester-forming derivative thereof is converted to tetramethylene glycol, 9,9- It reacts with diol components such as bis [4- (2-hydroxyethoxy) phenyl] fluorene and bisphenol A ethylene oxide adduct components to form monomers or oligomers, and then polycondensates under vacuum to obtain a predetermined intrinsic viscosity. It can be produced by a method of making a copolyester. At that time, a catalyst for promoting the reaction, for example, an esterification or transesterification catalyst or a polycondensation catalyst can be used, and various additives such as a stabilizer can be added.
The copolymerized polyester is applied to at least one surface of the film as a coating liquid, but since the in-line coating method applied when forming the film is preferable, the copolymerized polyester is preferably used as an aqueous dispersion. The method for forming the aqueous dispersion is not particularly limited, and a conventionally known method may be adopted.
(Other ingredients)
In the present invention, the copolyester used for the second easy-adhesion layer may contain an acid component or diol component other than those described above, and examples of the acid component include phthalic acid and phthalic anhydride. In addition, examples of the diol component include ethylene glycol, diethylene glycol, dipropylene glycol, xylene glycol, and dimethylolpropane. If the amount is slightly more, unsaturated acid components such as maleic acid and itaconic acid, polyfunctional acid components such as trimellitic acid and pyromellitic acid, polyfunctional hydroxy components such as glycerin and trimethylolpropane, and poly (ethylene oxide) Poly (alkylene oxide) glycol components such as glycol and poly (tetramethylene oxide) glycol may be used. In the present invention, the diol component is preferably an embodiment in which the above-mentioned essential or preferred diol component is contained in an essential or preferred content and the other diol component is an ethylene glycol component.
The range of preferable intrinsic viscosity (may be abbreviated as IV) of the copolyester of the second easy-adhesion layer is 0.2 to 0.8 dl / g, and the lower limit is further 0.3 dl / g, especially 0. .4 dl / g, and the upper limit is further preferably 0.7 dl / g, particularly preferably 0.6 dl / g. Here, the intrinsic viscosity is a value measured at 35 ° C. using orthochlorophenol.
Further, the glass transition temperature (Tg) of the copolymerized polyester of the second easy-adhesion layer is 70 ° C. or less from the viewpoint of coating film formability (film forming property) and adhesiveness when in-line coating is performed on a polyethylene terephthalate film. In view of blocking resistance, it is preferably 40 ° C. or higher, particularly 45 ° C. or higher.
Further, the refractive index of the copolyester makes it easy to suppress light interference spots (color spot feeling) by setting the refractive index of the second easy-adhesive layer to the above-mentioned preferred range, so that it is 1.58-1. It is preferably in the range of 65, more preferably in the range of 1.60 to 1.63, and particularly preferably in the range of 1.61 to 1.62. In order to satisfy the Tg and refractive index of the copolyester at the same time, the above-described preferred copolyester resin embodiment may be employed.
<Crosslinking agent>
In the second easy-adhesion layer, it is preferable to add a crosslinking agent in addition to the above-mentioned copolymerized polyester resin. Preferred examples of the crosslinking agent include an epoxy crosslinking agent, an oxazoline crosslinking agent, a melamine crosslinking agent, and an isocyanate crosslinking agent, and these may be used alone or in combination of two or more. May be.
Examples of the epoxy-based crosslinking agent include polyepoxy compounds, diepoxy compounds, monoepoxy compounds, glycidylamine compounds, and the like. Examples of the polyepoxy compounds include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether. , Diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, diepoxy compound, for example, neopentyl glycol diglycidyl ether, 1,6-hexanediol Diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene group As a co-diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, poly-1,4-butanediol diglycidyl ether, monoepoxy compound, for example, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether Examples of the glycidylamine compound include N, N, N ′, N′-tetraglycidyl-m-xylylenediamine and 1,3-bis (N, N-diglycidylamino) cyclohexane.
As the oxazoline-based crosslinking agent, a polymer containing an oxazoline group is preferable. It can be prepared by polymerization with addition polymerizable oxazoline group-containing monomers alone or with other monomers. Addition polymerizable oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and the like can be mentioned, and one or a mixture of two or more thereof can be used. Among these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially. The other monomer may be any monomer that can be copolymerized with an addition-polymerizable oxazoline group-containing monomer. For example, alkyl acrylate, alkyl methacrylate (alkyl groups include methyl, ethyl, n-propyl, isopropyl, n (Meth) acrylic acid esters such as butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group); acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene sulfone Unsaturated carboxylic acids such as acids and salts thereof (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); unsaturated nitriles such as acrylonitrile, methacrylonitrile; acrylamide, methacrylamide, N-alkylacrylamide, N-alkyl methacrylamide N, N-dialkylacrylamide, N, N-dialkyl methacrylate (alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl groups Unsaturated amides such as cyclohexyl groups, etc .; vinyl esters such as vinyl acetate, vinyl propionate, acrylic acid, methacrylic acid added with polyalkylene oxide; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether Α-olefins such as ethylene and propylene; halogen-containing α and β-unsaturated monomers such as vinyl chloride, vinylidene chloride and vinyl fluoride; α and β-unsaturated aromatics such as styrene and α-methylstyrene Group monomers and the like, one or more of these It is possible to use a monomer.
As the melamine-based crosslinking agent, a compound obtained by reacting methyl alcohol melamine derivative obtained by condensing melamine and formaldehyde with methyl alcohol, ethyl alcohol, isopropyl alcohol or the like as a lower alcohol and a mixture thereof are preferable. Examples of the methylol melamine derivative include monomethylol melamine, dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, hexamethylol melamine and the like.
Examples of the isocyanate-based crosslinking agent include tolylene diisocyanate, diphenylmethane-4,4′-diisocyanate, metaxylylene diisocyanate, hexamethylene-1,6-diisocyanate, 1,6-diisocyanate hexane, tolylene diisocyanate and hexanetriol. Adduct, adduct of tolylene diisocyanate and trimethylolpropane, polyol-modified diphenylmethane-4,4'-diisocyanate, carbodiimide-modified diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, 3,3 ' -Bitrylene-4,4 'diisocyanate, 3,3'dimethyldiphenylmethane-4,4'-diisocyanate, metaphenylene diisocyanate and the like.
Of these cross-linking agents, oxazoline-based cross-linking agents are particularly preferred from the viewpoints of ease of handling, pot life of the coating liquid, and the like.
By including a crosslinking agent for the second easy-adhesive layer, the solvent resistance (swelling resistance) and blocking resistance of the second easy-adhesive layer can be improved. Not only does the ratio decrease and the refractive index of the second easy-adhesive layer decreases, it becomes difficult to suppress light interference spots, but the second easy-adhesive layer tends to become harder and the adhesiveness tends to decrease. The content of the crosslinking agent is preferably in the range of 1 to 30% by mass, particularly preferably in the range of 5 to 10% by mass per 100% by mass of the second easy-adhesive layer.
Of these cross-linking agents, oxazoline-based cross-linking agents are particularly preferred from the viewpoints of ease of handling, pot life of the coating liquid, and the like.
Moreover, in the preferable aspect which employ | adopted the above-mentioned copolyester resin 2, the swelling rate with respect to the solvent of a 2nd easily bonding layer is easily made into a suitable value by containing the crosslinking agent concerning a 2nd easily bonding layer. However, if the amount is too large, the swelling rate tends to be too low and the adhesiveness tends to decrease. Therefore, the content of the crosslinking agent is 1 to 30% by mass per 100% by mass of the second easy-adhesive layer. The range is preferably in the range of 5 to 10% by mass.
<Crosslinkable addition polymer>
As described above, there is a strong demand for improving adhesiveness (wet heat adhesiveness) particularly in a wet heat environment.
This embodiment is a particularly suitable embodiment of a crosslinking agent for the purpose of excellent adhesion with a functional layer such as a hard coat layer in a wet heat environment.
In a 2nd easily bonding layer, wet heat adhesiveness can be improved by employ | adopting the crosslinkable addition polymer mentioned later as a crosslinking agent, It is preferable. In particular, in the above-described embodiment of the copolyester resin 1, an embodiment using the following crosslinkable addition polymer is particularly preferable because of high adhesiveness (wet heat adhesiveness).
In the present invention, the second easy-adhesion eyebrows are prepared by adding the following cross-linkable addition polymer in addition to the above-mentioned copolymer polyester resin (particularly preferably copolymer polyester resin 1), based on the mass of the second easy-adhesion layer. It is preferable to contain ~ 30% by mass.
Crosslinkable addition polymer:
(X1) containing 10 to 80 mol% of an addition polymerizable oxazoline group-containing monomer unit,
(Y1) A crosslinkable addition polymer having an addition polymerizable polyalkylene oxide group-containing monomer unit content of 5 mol% or less.
(However, the above mol% is a value based on 100 mol% of all monomer units of the crosslinkable addition polymer.
Thereby, it can be excellent in the adhesiveness in a humid-heat environment together with the adhesive improvement by the crack suppression of the 2nd easily bonding layer by employ | adopting the above-mentioned copolyester resin.
Examples of the addition polymerizable oxazoline group-containing monomer constituting the addition polymerizable oxazoline group-containing monomer unit include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl- 2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline and the like can be mentioned. These 1 type, or 2 or more types of mixtures can also be used. The addition polymerizable group for exhibiting the addition polymerization property is not particularly limited, but particularly from the viewpoint of further improving the adhesion with a functional layer such as a hard coat layer and from the viewpoint of easily obtaining the target compound. Residues or methacrylic residues are preferred, that is, the monomer is preferably an oxazoline group-containing acrylic monomer or an oxazoline group-containing methacrylic monomer. Among them, 2-isopropenyl-2-oxazoline is particularly preferable because it is easily available industrially.
The addition-polymerizable polyalkylene oxide group-containing monomer constituting the addition-polymerizable polyalkylene oxide group-containing monomer unit may have any addition-polymerizable group and polyalkylene oxide group, such as vinyl acetate, Preferable examples include vinyl esters such as those obtained by adding polyalkylene oxide to the ester portion of vinyl propionate, acrylic acid or methacrylic acid. Here, the alkylene group in the polyalkylene oxide group is, for example, one having 2 to 30 carbon atoms, preferably an alkylene group having 2 to 20 carbon atoms, more preferably 2 to 10 carbon atoms, and still more preferably. Are an ethylene group, a propylene group, and a butylene group. The number of repeating alkylene groups in the polyalkylene oxide group (average) is, for example, 2 to 30, preferably 4 to 20, and more preferably 5 to 15. In the case of a polyalkylene oxide group comprising a plurality of types of alkylene groups, the total number of repetitions is preferably within the above range.
The crosslinkable addition polymer in the present invention contains 10-80 mol% of monomer units composed of the above addition polymerizable oxazoline group-containing monomer in the polymer with respect to 100 mol% of all monomer units of the polymer. And the content of the monomer unit composed of the addition-polymerizable polyalkylene oxide group-containing monomer as described above in the polymer is 5 mol% or less with respect to 100 mol% of all monomer units of the polymer. Is. By setting it as such a structure, the adhesiveness in a humid heat environment can be made high.
If the content of the addition-polymerizable oxazoline group-containing monomer unit is too small, the adhesiveness in a moist heat environment is inferior. From this viewpoint, it is preferably 20 mol% or more, more preferably 30 mol% or more, still more preferably 40 mol% or more, and particularly preferably 50 mol% or more. On the other hand, if the amount is too large, a problem of film formation deteriorates. From this viewpoint, it is preferably 75 mol% or less, more preferably 70 mol% or less.
Moreover, when there is too much content of an addition polymerizable polyalkylene oxide group containing monomer unit, it will be inferior to the adhesiveness in a wet heat environment. From this viewpoint, it is preferably 4 mol% or less, more preferably 3 mol% or less, and still more preferably 2 mol% or less. Ideally, it is an embodiment that does not contain addition-polymerizable polyalkylene oxide group-containing monomer units.
In this embodiment, the crosslinkable addition polymer only needs to have a structure satisfying the requirements of the above (X1) and (Y1), and the other monomer units are addition polymerizable in a range that does not impair the purpose of this embodiment. Any monomer unit may be used as long as it is composed of any addition polymerizable monomer capable of addition polymerization with an oxazoline group-containing monomer and an addition polymerizable polyalkylene oxide group-containing monomer. Such optional addition polymerizable monomers include, for example, alkyl acrylate, alkyl methacrylate (alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2 (Meth) acrylic acid esters such as ethylhexyl group and cyclohexyl group); acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrenesulfonic acid and salts thereof (sodium salt, potassium salt, ammonium salt) Unsaturated nitriles such as acrylonitrile and methacrylonitrile; acrylamide, methacrylamide, N-alkylacrylamide, N-alkylmethacrylamide, N, N-dialkylacrylamide, N, N-dia Unsaturated amides such as kill methacrylate (alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, cyclohexyl, etc.) Vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; halogen-containing α and β-unsaturated monomers such as vinyl chloride, vinylidene chloride and vinyl fluoride; styrene, α-methyl styrene, Α, β-unsaturated aromatic monomers and the like can be used, and one or more of these monomers can be used.
The content of the crosslinkable addition polymer in the second easy-adhesive layer is preferably 1 to 30% by mass based on the mass of the second easy-adhesive layer. The adhesiveness tends to decrease, and if it is less than the above lower limit, the adhesiveness in a moist heat environment is inferior. From this viewpoint, the content of the crosslinkable addition polymer is more preferably 2% by mass or more, and further preferably 3% by mass or more. On the other hand, when the content is large, the refractive index of the second adhesive layer tends to be lowered. Therefore, when the upper limit is exceeded, the interference spots are inferior. From this viewpoint, it is more preferably 20% by mass or less, and still more preferably 10% by mass or less.
In this embodiment, a crosslinking agent different from the above-mentioned crosslinkable addition polymer can be blended and used in combination in the second easy-adhesion layer within a range that does not impair the purpose of this embodiment. As such a crosslinking agent, an epoxy-type crosslinking agent, a melamine-type crosslinking agent, an isocyanate-type crosslinking agent, etc. can be illustrated, These may use 1 type and may use 2 or more types together.
The second easy-adhesion layer of the present embodiment adopting the above-mentioned crosslinkable polymer has excellent adhesiveness with a functional layer such as a hard coat layer in a moist heat environment, and suppression of light interference spots after the functional layer is formed. In the case of the main purpose, the second easy-adhesion layer can be provided on one or both sides of the polyester film without having the first easy-adhesion layer to obtain a laminated polyester film. Such a laminated polyester film includes the following embodiments.
1. A laminated polyester film having a second easy-adhesion layer on at least one surface of an oriented polyethylene terephthalate film, wherein the second easy-adhesion layer is 70% by mass or more of the following copolyester based on the mass of the second easy-adhesion layer, and A laminated polyester film containing 1 to 30% by mass of the following crosslinkable addition polymer.
Copolyester:
(A1) 60-90 mol% of naphthalenedicarboxylic acid component,
(B1) 15 to 50 mol% in total of the alkylene dicarboxylic acid component having 6 to 12 carbon atoms and the alkylene glycol component having 4 to 10 carbon atoms, and
(C1) A copolyester containing a glycol component having a fluorene structure represented by the formula (I) in an amount of 5 mol% to less than 20 mol%.
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
Crosslinkable addition polymer:
(X1) containing 10 to 80 mol% of an addition polymerizable oxazoline group-containing monomer unit,
(Y1) A crosslinkable addition polymer having an addition polymerizable polyalkylene oxide group-containing monomer unit content of 5 mol% or less.
(The above mol% is a value based on 100 mol% of all monomer units of the crosslinkable addition polymer.)
2. The copolyester is further
(D2) 5-25 mol% of bisphenol A ethylene oxide adduct component
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
The laminated polyester film according to 1 above, comprising:
3. The copolymerized polyester is
(A3) The proportion containing a naphthalenedicarboxylic acid component is 60 to 80 mol%,
(B3) the proportion of the alkylene dicarboxylic acid component having 6 to 12 carbon atoms is 0 mol%,
(E3) containing 20 to 40 mol% of terephthalic acid and / or isophthalic acid component,
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
3. The laminated polyester film as described in 1 or 2 above.
4). 4. The laminated polyester film as described in any one of 1 to 3 above, which is used as an easily adhesive polyester film for optics.
<Other ingredients>
Various additives can be blended in the second easy-adhesion layer of the present invention within a range not impairing the object of the present invention. For example, particles, waxes, surfactants, wetting modifiers, etc. may be added to improve film slipperiness, scratch resistance, wettability during coating, and other antistatic agents, UV absorbers, etc. Etc. may be blended.
For example, by adding particles, the slipperiness and scratch resistance of the film can be improved. Such particles may be any of organic particles, inorganic particles, and organic-inorganic composite particles. From the viewpoint of improving scratch resistance while maintaining transparency, large particles (particles), It is preferable to contain both small particles (small particles).
The average particle size of the large particles is suitably in the range of 80 to 1000 nm, more preferably in the range of 100 to 400 nm, and still more preferably in the range of 130 to 350 nm. Thereby, it is excellent in lubricity and scratch resistance. In addition, since a large particle is easy to drop | omit from a 2nd easily bonding layer, it is preferable that it is an organic inorganic composite particle which coat | covered the inorganic particle surface with organic substance (for example, acrylic).
The content of the large particles in the second easy-adhesion layer is preferably 0.1 to 5% by mass, more preferably 0.1 to 1% by mass with respect to the mass of the second easy-adhesion layer. The effect of adding is easier to obtain.
The average particle size of the small particles is suitably in the range of 10 nm or more and less than 100 nm, more preferably 20 to 80 nm, still more preferably 30 to 60 nm. Thereby, it is excellent in blocking resistance. From the viewpoint of hardness, the small particles are preferably inorganic particles, and are preferably metal oxide particles. Examples of the metal oxide particles include silica particles, alumina particles, titania particles, and zirconia particles. Among these, silica particles and titania particles are preferable from the viewpoint of excellent cost.
The content of the small particles in the second easy-adhesion layer is preferably 0.1 to 5% by mass, more preferably 1 to 3% by mass with respect to the mass of the second easy-adhesion layer, and the small particles are added. The effect is easier to obtain.
The second easy-adhesion layer can contain a surfactant. By containing a surfactant in the coating liquid for forming the second easy-adhesion layer, the coating properties of the coating liquid can be improved. Such a surfactant is not particularly limited as long as it has an effect of enhancing the coating property to a polyethylene terephthalate film. For example, nonionic surfactants, cationic surfactants, anionic surfactants, amphoteric interfaces. Any activator can be used. Of these, nonionic surfactants are preferred from the viewpoint of particularly low foaming and good coatability. Preferred examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxypropylene alkyl ether, and polyoxyethylene propylene copolymer alkyl ether.
When using a surfactant, it is preferable to use it in an amount of 20% by mass or less based on the mass of the second easy-adhesion layer. Thereby, there exists a tendency for the adhesive improvement effect to become high. From this viewpoint, it is more preferably 15% by mass or less, and further preferably 10% by mass or less. Moreover, the lower limit of the addition amount is preferably 1% by mass, more preferably 3% by mass or more, and further preferably 5% by mass or more from the viewpoint of the coating property described above.
<Method for producing polyester film>
An example is given and demonstrated about the method for manufacturing the polyester film in this invention. In addition, the polyester film in this invention is not limited to this.
The polyester film in the present invention is obtained by, for example, melt-extruding the above polyester into a film shape, cooling and solidifying with a casting drum to form an unstretched film, and this unstretched film is longitudinal (Tg + 60) ° C. In some cases, it may be referred to as “longitudinal direction or MD”) once or twice or more so that the total magnification becomes 3 to 6 times to form a uniaxially stretched film. Here, Tg is the glass transition temperature of the polyester constituting the film. Preferably, the coating liquid for forming the 1st easily bonding layer mentioned later here is apply | coated. Next, the magnification is 3 to 5 times in the width direction (the direction perpendicular to the film forming machine axis direction and the thickness direction, sometimes referred to as the transverse direction or TD) at Tg ~ (Tg + 60) ° C. It is obtained by stretching, and if necessary, heat treatment at 180-230 ° C. for 1-60 seconds and re-heat treatment while shrinking 0-20% in the width direction at a temperature 10-20 ° C. lower than the heat treatment temperature. Can do.
The refractive index of the biaxially oriented polyester film can be adjusted by the draw ratio. The higher the draw ratio, the higher the refractive index. However, since the thermal dimensional stability is impaired as the draw ratio increases, the draw ratio is preferably in the range of 3.0 to 4.0 in the longitudinal direction and the width direction, more preferably 3.3 to 3. It is 8 times, more preferably 3.4 to 3.7 times.
In the present invention, in the production of the polyester film, the sequential biaxial stretching method as described above can be adopted, but the simultaneous biaxial stretching method can also be adopted. At that time, the stretching conditions and the like are the same as those described above. In this case, the coating liquid for forming the easy-adhesion layer is applied to the unstretched film.
The thickness of the polyester film used in the present invention is preferably in the range of 20 to 200 μm. In particular, when used in a capacitive touch sensor, it can be appropriately selected according to the characteristics of the controller IC in order to ensure a predetermined capacitance.
<Method for producing laminate>
An example is given and demonstrated about the method for manufacturing the laminated body of this invention. In addition, the laminated body of this invention is not limited to this.
(Formation method of a 1st easily bonding layer)
The first easy-adhesion layer is coated with a coating liquid for forming the first easy-adhesion layer (hereinafter sometimes referred to as a first easy-adhesion coating liquid) on the polyester film, and is dried and necessary. It can form by hardening according to. Preferably, it is a so-called in-line coating method in which the first easy-adhesion coating liquid is applied during the production process of the polyester film to form the first easy-adhesion layer. Thereby, the adhesiveness of a polyester film and a 1st easily bonding layer can be made high. Even if the thickness of the first easy-adhesion layer is very thin, the thickness can be controlled with high accuracy.
The first easy-adhesive coating liquid can be obtained by mixing the components constituting the first easy-adhesive layer described above and diluting with a solvent as necessary. Here, each component may be added as it is, or may be added after dissolving or dispersing in an appropriate solvent, or may be diluted with an appropriate solvent. The concentration of the coating liquid can be appropriately set depending on the viscosity of the coating liquid, the coating thickness, the coating method, and the like.
A conventionally well-known method can be employ | adopted as a coating system for forming a 1st easily bonding layer. Examples thereof include a roll coating method (such as a gravure roll coating method) and a spray coating method.
(Method for forming high refractive index layer and low refractive index layer)
The high refractive index layer and the low refractive index layer can be formed by either a wet method or a dry method. An optical adjustment layer is formed by forming a high refractive index layer on the first easy-adhesion layer or further forming a low refractive index layer on the high refractive index layer by any suitable method. do it.
In the wet method, a coating liquid for forming a high refractive index layer (hereinafter referred to as a high refractive index coating) is formed by a doctor method, a bar coater, a gravure roll coater, a curtain coater, a knife coater, a spin coater, a spray method, a dipping method, or the like. And a coating liquid for forming a low refractive index layer (hereinafter sometimes referred to as a low refractive index coating liquid) is applied to the surface on which the layer is to be formed. The coating film is dried, and the coating film is dried and, if necessary, cured by heat, ultraviolet rays, an electron beam or the like, whereby a high refractive index layer and a low refractive index layer can be formed. Such a coating solution may be a sol, whereby a metal oxide film is obtained. In addition, what is necessary is just to select drying conditions and hardening conditions suitably. Depending on the solvent of the coating solution, the drying temperature is, for example, 50 to 100 ° C., preferably 60 to 90 ° C. As the irradiation intensity of ultraviolet rays or electron beams in curing, for example, 100 to 2000 mJ / m ² It is. The solid content concentration of the coating liquid can also be appropriately selected depending on the intended coating amount and the coating method used. For example, it is 1 to 70% by mass.
According to the wet method, a layer containing metal oxide fine particles in a binder resin, a layer made of a metal oxide film by a sol-gel method, a metal oxide film containing metal oxide particles, organic particles, and a binder resin It is suitable for forming the layer which carries out.
In the dry method, a PVD method such as a sputtering method, a vacuum deposition method, or an ion plating method, a printing method, a CVD method, or the like can be applied. The dry method is suitable for forming a layer made of metal or a layer made of a metal oxide film. Note that the conditions may be appropriately adjusted in consideration of the type of target, the target layer thickness, and the like.
<Transparent conductive film>
In the present invention, a transparent conductive layer having a refractive index of 1.9 to 2.3 is formed on the optical adjustment layer of the laminate obtained above, in particular, on the low refractive index layer. Can be obtained.
In the present invention, the transparent conductive layer is not particularly limited as long as it is within the above refractive index range, and examples thereof include a layer made of a crystalline metal or a crystalline metal compound. Examples of the component constituting the transparent conductive layer include metal oxides such as silicon oxide, aluminum oxide, titanium oxide, magnesium oxide, zinc oxide, indium oxide, and tin oxide. Of these, a crystalline layer mainly composed of indium oxide is preferable, and a layer made of crystalline ITO (Indium Tin Oxide) is particularly preferably used. When the transparent conductive layer is a crystalline film, the environmental reliability required for the touch panel tends to be improved. The crystallization method is not particularly limited, and for example, crystallization can be performed by heat treatment at 120 to 160 ° C. for about 60 to 90 minutes.
A layer made of a conductive polymer such as polyacetylene, polyparaphenylene, polythiophene, polyethylenedioxythiophene, polypyrrole, polyaniline, polyacene, polyphenylene vinylene, or the like can also be employed.
The film thickness of the transparent conductive layer is preferably 5 to 50 nm from the viewpoints of transparency and conductivity. More preferably, it is 5 to 30 nm. When the film thickness of the transparent conductive layer is less than 5 nm, the resistance stability with time tends to be inferior, and when it exceeds 50 nm, the surface resistance value tends to decrease. In addition, the color tone of the film becomes strong and the pattern tends to be emphasized.
When the transparent conductive film of the present invention is used for a touch panel, the surface resistance value of the transparent conductive layer at a thickness of 10 to 30 nm is more preferably 100 to 1000Ω / □, more preferably due to reduction of power consumption of the touch panel and circuit processing. It is preferable to use a transparent conductive layer exhibiting a range of 140 to 600Ω / □.
<Method for producing transparent conductive film>
The transparent conductive layer can be formed by a known method. For example, a physical formation method (such as a DC magnetron sputtering method, an RF magnetron sputtering method, an ion plating method, a vacuum deposition method, a pulse laser deposition method) (Physical Vapor Deposition (PVD)) or the like can be used, but DC magnetron sputtering is desirable from the viewpoint of industrial productivity of forming a metal compound layer having a uniform film thickness over a large area. In addition to the physical formation method (PVD), a chemical formation method such as chemical vapor deposition (CVD) or a sol-gel method can be used. A sputtering method is preferred.
In addition, the transparent conductive layer in this invention is patterned. Here, patterning refers to an aspect in which a portion where the transparent conductive layer exists in a prescribed shape and a portion where the transparent conductive layer does not exist are formed. That is, the transparent conductive layer is formed on a part of the laminate of the present invention. The specified shape may be a known shape that can be used as an electrode of a capacitive touch panel. For example, there are fine wire and tiremond patterns. The patterning method is not particularly limited, and a conventionally known etching method can be used.
<Method for forming second easy-adhesion layer>
The second easy-adhesion layer is coated with a coating liquid for forming the second easy-adhesion layer (hereinafter sometimes referred to as a second easy-adhesion coating liquid) on the polyester film, and then dried. It can form by hardening according to. Preferably, a so-called in-line coating method is used in which the second easy-adhesion coating liquid is applied to form the second easy-adhesion layer during the production process of the polyester film. Thereby, the adhesiveness of a polyester film and a 2nd easily bonding layer can be made high. Moreover, even if the thickness of the second easy-adhesion layer is very thin, the thickness can be controlled with high accuracy. Particularly preferably, during the production process of the polyester film, the second easy-adhesion coating solution is applied to the surface opposite to the surface to which the first easy-adhesion coating solution is applied, and the first easy-adhesion layer and the second easy-adhesion layer are formed simultaneously. Manufacturing method.
A 2nd easily-adhesive coating liquid can mix and obtain the component which comprises the 2nd easily-adhesive layer mentioned above, and can obtain it by diluting with a solvent as needed. Here, each component may be added as it is, or may be added after dissolving or dispersing in an appropriate solvent, or may be diluted with an appropriate solvent. The concentration of the coating liquid can be appropriately set depending on the viscosity of the coating liquid, the coating thickness, the coating method, and the like.
A conventionally well-known method can be employ | adopted as a coating system for forming a 2nd easily bonding layer. Examples thereof include a roll coating method (such as a gravure roll coating method) and a spray coating method.
The second easy-adhesion layer can be formed before forming the first easy-adhesion layer. Moreover, a 2nd easily bonding layer can also be formed on both surfaces of a polyester film depending on the objective. The following is a description of a particularly preferable manufacturing method for forming the second easily adhesive layer in such a case.
The polyester film which has a 2nd easily bonding layer is manufactured through the film forming process which manufactures a biaxially-oriented polyester film, and the application | coating process which forms a 2nd easily bonding layer. The film forming step may be a sequential biaxial stretching method or a simultaneous biaxial stretching method, but if it is a simultaneous biaxial stretching method, the film surface is hardly damaged during film formation, Since it is suitable for manufacturing the film used for an optical use, it is preferable. The coating process may be after the film forming process (so-called off-line coating method) or in the film forming process (so-called in-line coating method). For example, a thin coating layer can be easily obtained uniformly, and a strong coating layer can be obtained. Furthermore, it is excellent in productivity.
In the second easy-adhesion layer, using the copolyester resin 1 or 3, the effect of improving the easy-adhesive property by improving the film-forming property is to be applied to the unstretched film or the partially oriented film before completion of the orientation. Is produced by an in-line coating method in which the film is stretched and heat-set after being provided. The film forming method may be a sequential biaxial stretching method or a simultaneous biaxial stretching method. In the simultaneous biaxial stretching method, the second easy-adhesive layer is used to stretch the biaxial simultaneously. When the coating liquid for forming the film is stretched after coating, the film forming property of the second easy-adhesive layer becomes more severe. Therefore, especially in such a case, the embodiment using the above-described copolymer polyester resins 1 and 3 is particularly useful.
Hereinafter, a preferable method when polyethylene terephthalate is used as the polyester and the in-line coating method is adopted by the simultaneous biaxial stretching method will be described. First, sufficiently dried polyethylene terephthalate is melted at a temperature of Tm + 10 ° C. to Tm + 30 ° C. (where Tm is the melting point of polyethylene terephthalate), extruded into a sheet, and cooled with a cooling drum to form an unstretched film. Next, a coating solution for forming the second easy-adhesion layer is applied to the surface of the unstretched film on the side where the second easy-adhesion layer is to be formed by using a roll coater to obtain an unstretched film having a coating film. At this time, coating is performed so that the thickness of the second easy-adhesion layer in the obtained film is preferably 50 to 100 nm, more preferably 70 to 90 nm. Next, this was preheated at 90 to 110 ° C., and simultaneously in the biaxial direction with a simultaneous biaxial stretching machine at a temperature of Tg to Tg + 70 ° C. (where Tg is the glass transition temperature of polyethylene terephthalate) and in the longitudinal direction (film formation) Preferably in the machine axis direction, longitudinal direction or MD) 2.5 to 5.0 times, more preferably 3.0 to 4.0 times, lateral direction (direction perpendicular to the film forming machine axis direction, width direction or TD) ) Is preferably 2.5 to 5.0 times, more preferably 3.0 to 4.0 times, and then heat-fixed at a temperature of (Tg + 60 ° C.) to Tm, preferably adjusting the heat shrinkage rate. Therefore, a laminated film having a second easy-adhesion layer on the oriented polyethylene terephthalate film can be obtained by heat relaxation treatment. In addition, it is preferable that this extending | stretching temperature is 45 degreeC or more higher than the glass transition temperature of the copolyester in a 2nd easily bonding layer, More preferably, it is 50 degreeC or more, More preferably, it is 55 degreeC or more higher temperature. That is. Thereby, the film-forming property of the second easy-adhesion layer becomes more excellent, and the effect of improving the adhesiveness can be enhanced. Further, the temperature is preferably 40 ° C. or higher than the glass transition temperature of the second easy-adhesion layer, more preferably 45 ° C. or higher, and even more preferably 53 ° C. or higher. The film forming property of the easy-adhesion layer is more excellent, and the effect of improving the adhesiveness can be increased. Next, for heat setting, for example, a polyethylene terephthalate film is preferably heat-set at a temperature in the range of 210 to 240 ° C. for 1 to 60 seconds. In addition, the coating film is dried by the heat applied in the above process, and is cured as necessary to become a second easy-adhesion layer.
In addition, the coating liquid for forming a 2nd easily bonding layer mixes each component which comprises a 2nd easily bonding layer, and considers a viscosity, application | coating thickness, etc., and adjusts it suitably. The solvent used for dilution is preferably water, that is, the coating liquid is preferably aqueous. The solid concentration of the coating liquid is preferably 5 to 20% by mass, and a good coating appearance can be obtained.
<Characteristics of laminated film>
(Haze)
The laminated film of the present invention preferably has a haze value measured according to JIS standard K7136 of 0% or more and 1.0% or less, more preferably 0.1% or more and 0.8% or less, particularly preferably 0. .1% or more and 0.5% or less. Haze is an important evaluation index for use in optical applications. For example, when used for a display, haze is one of the indexes for evaluating the visibility of a display, and when haze exceeds 1.0%, Since the transparency of the film is lowered and the display screen of the display looks whitish, the contrast is lowered and the visibility may be lowered. In order to make the haze within such a range, in the polyester film and the easy-adhesion layer, particles are not used or even when used, the diameter and amount are within the above-mentioned range, and the polymer binder constituting the easy-adhesion layer is the above-mentioned. A preferable copolyester resin may be used.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to such examples. Various measurements in the examples were performed as follows.
(1) Refractive index of the easily adhesive layer
1-1. Refractive index of the first easy-adhesion layer
With the ellipsometer (M-200) manufactured by JASCO Corporation, the phase difference (delta) and the amplitude (psi) are measured for the first easy-adhesion layer-forming surface of the polyester film having the first easy-adhesion layer. The refractive index of the 1st easily bonding layer in wavelength 550nm was calculated | required.
1-2. Refractive index of the second easy adhesion layer
The coating liquid for forming the second easy-adhesion layer was dried into a plate at 90 ° C. and measured with an Abbe refractometer (D-line 589 nm) to obtain the refractive index of the second easy-adhesion layer.
(2) Refractive index of polyester film
2-1. Average refractive index in the plane direction of polyester film 1
As the average refractive index in the plane direction of the polyester film, a numerical value obtained by measurement using an Abbe refractometer (D line 589 nm) was used. That is, the longitudinal direction of the polyester film is 90 °, the width direction perpendicular to it is 0 °, the refractive index is measured every 5 °, the direction showing the maximum refractive index is specified, and the refraction in the direction perpendicular to the direction is determined. The average of these refractive indexes was taken as the average refractive index in the plane direction.
This measurement method was used in the following examples and comparative examples.
2-2. Average refractive index in the plane direction of polyester film 2
The refractive index of each of the obtained biaxially stretched polyester film in the longitudinal direction (MD), the width direction (TD), and the film thickness direction (Z direction) was measured with an Abbe refractometer. In addition, since the thickness of the easy-adhesion layer is thin, even if the easy-adhesion layer is formed on both sides, even if it is measured from above the easy-adhesion layer using an Abbe refractometer, it is affected by the refractive index of the easy-adhesion layer. The refractive index of the biaxially oriented polyester film can be obtained.
Surface direction refractive index = (longitudinal direction refractive index + width direction refractive index) / 2
This measurement method was used in the following Reference Examples and Reference Comparative Examples.
(3) Refractive index of other layers and resin
3-1. Refractive index of polyester resin of high refractive index layer, low refractive index layer, first easy adhesion layer
Using a laser refractometer prism coupler, model 2010, manufactured by Metricon, the dried product of the coating liquid for forming each layer was measured using a wavelength of 633 nm. In addition, the dried product of the coating liquid for forming each layer was prepared by drying the coating liquid in an oven at 80 ° C. for 24 hours under normal pressure.
3-2. Refractive index of the copolyester resin of the second easy adhesion layer
The solution or dispersion of the copolyester was dried into a plate at 90 ° C. and measured with an Abbe refractometer (D line 589 nm).
(4) Film thickness
4-1. Film thickness of first easy-adhesion layer, high refractive index layer, low refractive index layer, transparent conductive layer
The film thickness of each layer was measured by observing the cross section of the film sample with a field emission type transmission electron microscope HF-3300 manufactured by Hitachi, Ltd.
4-2. Film thickness of the second easy adhesion layer
The film is fixed with an embedding resin, the cross section is cut with a microtome, stained with 2% osmic acid at 60 ° C. for 2 hours, and the cross section is observed with a transmission electron microscope (JEM 2010 manufactured by JEOL). The thickness of the adhesive layer was measured.
(5) Glass transition temperature
5-1. Glass transition temperature of copolyester.
10 mg of copolymer polyester sample is sealed in an aluminum pan for measurement and attached to a differential calorimeter (DuPont V4.OB2000 DSC), and the temperature is raised from 25 ° C. to 300 ° C. at a rate of 20 ° C./min. It was taken out after being kept at 300 ° C. for 5 minutes, immediately transferred onto ice and rapidly cooled. The pan was again attached to the differential calorimeter, and the glass transition temperature was measured by increasing the temperature from 25 ° C. to 20 ° C./min.
5-2. Glass transition temperature of easily adhesive layer
A 10 mg sample obtained by drying a coating solution for forming an easy-adhesion layer into a plate at 90 ° C. is sealed in an aluminum pan for measurement and placed in a differential calorimeter (DuPont V4.OB2000 DSC). The glass transition temperature was measured by raising the temperature from 25 ° C. to 300 ° C. at a rate of 20 ° C./min.
(6) Evaluation of the first adhesive layer
6-1. Adhesiveness
Using a sample in which a high refractive index layer is formed on the first easy-adhesion layer, a cross cut (1 mm) on the high refractive index layer ² 100 squares), a 24 mm wide cellophane tape (manufactured by Nichiban Co., Ltd.) is pasted thereon, abruptly peeled off at a 180 ° peeling angle, and the crosscut portion is visually observed. The adhesion between the easy adhesion layer and the high refractive index layer was evaluated according to the following criteria.
○: Peeling area is less than 20% ... good adhesion
Δ: Peeling area of 20% or more and less than 50%: Adhesive strength is slightly good
X: Peeling area is 50% or more ... adhesive strength failure
6-2. Pattern visibility (evaluation of bone appearance)
In the transparent conductive film having the patterned transparent conductive layer, the boundary between the portion where the transparent conductive layer exists and the portion where the transparent conductive layer does not exist was visually observed, and the visibility was evaluated according to the following criteria.
○: The border is hardly visible
Δ: The border is slightly conspicuous
×: The boundary looks prominent
(7) Evaluation of the second easily adhesive layer
7-1. Hard coat layer adhesion ((initial) adhesion)
1mm on the hard coat layer of the film on which the hard coat layer is formed ² 100 cross-cuts are put, cellophane tape (manufactured by Nichiban Co., Ltd.) is pasted on it, pressed firmly with fingers, peeled in the direction of 90 °, and evaluated as follows according to the number of remaining hard coat layers. went.
A: 90 <remaining number ≦ 100 ... adhesiveness is very good
◯: 80 <remaining number ≦ 90 ... adhesiveness good
Δ: 70 <remaining number ≦ 80 ... adhesiveness is slightly good
×: Remaining number ≦ 70 ... Adhesive failure
7-2. Hard coat layer adhesion (wet heat adhesion)
The film on which the hard coat layer was formed was immersed in 100 ° C. boiling water (ion-exchanged water) for 2 hours under normal pressure, and then evaluated for adhesiveness in the same manner as in 7-1 above.
7-3. Swelling rate
The thickness of the second easy adhesion layer of the film after laminating the hard coat layer was measured in the same manner as in 4-2 above. The swelling ratio E (%) of the second easy-adhesion layer was determined by the following formula 1 when the thickness of the second easy-adhesion layer before lamination of the hard coat layer was d0 and the thickness after lamination was dh. .
E = dh / d0 × 100
Further, the swelling ratio E was evaluated as follows.
A: 100 ≦ E <130, very good swelling property
○: 130 ≦ E ≦ 200. Good swelling property.
Δ: 200 <E ... Swellability defect
7-4. Interference spots
Using a film with a hard coat layer, the surface opposite to the surface on which the hard coat layer is formed is painted with black magic to eliminate the effect of reflected light from the opposite surface, and a spectrophotometer (Shimadzu Corporation) Spectral reflectance was measured using UV-3101PC). The reflectance at a wavelength of 500 to 600 nm was measured, and the amplitude of the reflectance was evaluated according to the following criteria. At that time, the evaluation was performed with the short-period amplitude obtained by correcting the long-period fluctuation of the reflectance. As the amplitude of the measured reflectance is larger, interference spots are generated, and the visibility as a display is lowered.
A: Reflectance amplitude ≦ 0.5% ・・・ Interference spots are extremely good
○: 0.5% <reflectance amplitude ≦ 1.0%.
×: 1.0% <reflectance amplitude: defective interference spots
7-5. Blocking resistance
Two films were overlapped so that the second easy-adhesion layer forming surfaces were in contact with each other, and 0.6 kg / cm over 17 hours under an atmosphere of 60 ° C. and 80% RH. ² Then, the film was peeled off, and the blocking resistance was evaluated according to the following criteria by the peeling force.
A: Peeling force <98 mN / 5 cm: very good blocking resistance
○: 98 mN / 5 cm ≦ peeling force <147 mN / 5 cm: good blocking resistance
Δ: 147 mN / 5 cm ≦ peeling force <196 mN / 5 cm: Slightly good blocking resistance
×: 196 mN / 5 cm ≦ peeling force: poor blocking resistance
7-6. Haze value of laminated film
According to JIS K7136, the haze value of the film was measured using the haze measuring device (NDH-2000) by Nippon Denshoku Industries Co., Ltd. The irradiation surface was the second easily adhesive layer surface. In addition, the aspect of the crack on the surface of the second easy-adhesive layer can be evaluated by the height of the haze. If the conditions are the same, the higher the haze (surface haze), the more surface cracks, and preferably It is 0.8% or less, more preferably 0.7% or less, further preferably 0.6% or less, and particularly preferably 0.5% or less.
[Example 1-1]
(Manufacture of a polyester film having a first easy-adhesion layer)
A polyethylene terephthalate (PET) chip having an intrinsic viscosity of 0.60 dl / g is dried at a temperature of 120 to 150 ° C., melted at a temperature of 290 ° C. using an extruder, and passed through a slit-shaped die on a casting drum. Extruded to cool. The obtained unstretched film was continuously sent to the stretching step, and stretched 3.5 times in the longitudinal direction at a temperature of 110 ° C., and then an aqueous dispersion of a copolymer polyester resin shown in Table 1-1 and a crosslinking agent (acrylic). Resin) and an aqueous dispersion of titanium oxide particles (refractive index 2.5) (trade name: titanium oxide slurry, average particle size 80 nm, manufactured by CI Kasei Co., Ltd.) The coating liquid A obtained by mixing so as to have the ratio shown as coating liquid A in Table 1-2 and diluting the coating liquid with ion-exchanged water so that the solid content concentration becomes 10% by mass is a gravure. It applied to one side using the roll coater. The coating thickness was adjusted to 15 nm after drying.
Subsequently, the both ends of the film coated with the coating liquid were grasped with clips, preheated at 100 ° C. for 2 minutes, stretched 3.6 times in the transverse direction at a temperature of 130 ° C., and heat-fixed at 230 ° C. for 2 minutes. A biaxially oriented polyester film having one easy adhesion layer was obtained. The thickness of this polyester film was 125 μm. The maximum refractive index in the surface direction was 1.66, the refractive index in the direction orthogonal to the direction showing the maximum refractive index was 1.64, and the average refractive index in the surface direction was 1.65.
(Formation of optical adjustment layer)
On the first easy-adhesion layer of the obtained biaxially oriented polyester film, tetrabutyl titanate tetramer (Nihon Soda TBT B-4) in a ligroin / n-butanol (3/1 vol%) solution, A coating solution obtained by adding 15 parts by mass of γ-glycidoxypropyltrimethoxysilane to 100 parts by mass of alkoxide is applied by microgravure coating, dried at 150 ° C. for 2 minutes, and has a high refractive index of 150 nm. A layer (refractive index 1.65) was formed.
Further, a SiO2 sol obtained by dissolving tetraethylsilicate in ethanol, adding water and hydrochloric acid and hydrolyzing it is applied, heat-treated at 100 ° C. for 2 minutes, and having a thickness of 30 nm. ₂ A gel film (refractive index 1.45)) was formed as a low refractive index layer. Thus, an optical adjustment layer composed of two layers of a high refractive index layer and a low refractive index layer having different refractive indexes was formed, and a laminate was prepared.
(Formation of transparent conductive layer)
An ITO layer (refractive index 2.1) is formed on the low refractive index layer in the laminate by sputtering using an indium oxide-tin oxide target having a composition of indium oxide and tin oxide of 95: 5 by weight and a packing density of 98%. Formed. The film thickness of the formed ITO layer was 40 nm. Next, on the ITO layer, a photoresist patterned in stripes is applied and formed, dried and cured, and then immersed in 25 ° C., 5% hydrochloric acid (aqueous hydrogen chloride solution) for 1 minute. Etching of the ITO film was performed. Thereafter, the photoresist was removed. Further, heat treatment was performed at 150 ° C. for 90 minutes to crystallize the ITO film, and a patterned transparent conductive layer was formed. The characteristics of the transparent conductive film thus obtained are shown in Table 1-3.
[Examples 1-2 to 1-4, Comparative Examples 1-1 to 1-4]
A laminated body in the same manner as in Example 1 except that the coating liquid shown in Table 1-3 was used and the thickness of the first easy-adhesion layer was changed to the thickness shown in Table 1-3 by adjusting the wet coating amount. And the transparent conductive film was obtained. The evaluation results are shown in Table 1-3.

Below, the reference example which employ | adopted the copolyester resin 1 as a copolyester resin of a 2nd easily bonding layer is shown.
[Reference Examples 2-1 to 2-8, Reference Comparative Examples 2-1 to 2-4]
Molten polyethylene terephthalate ([η] = 0.63 dl / g, Tg = 78 ° C.) was extruded from a die and cooled with a cooling drum by a conventional method to form an unstretched film. An aqueous coating solution having a solid content concentration of 10% by mass having the composition shown in (1) was uniformly applied with a roll coater so that the thickness of the second easy-adhesion layer obtained after stretching was 75 nm.
Next, this coated film was preheated at a temperature of 100 ° C., dried, and stretched simultaneously in the longitudinal and transverse directions at a magnification of 3.2 times in the longitudinal direction and 3.7 times in the transverse direction at 120 ° C. in a simultaneous biaxial stretching machine. And heat-fixed for 60 seconds to obtain a laminated polyester film having a second easy-adhesion layer on both sides of a 125 μm thick biaxially oriented polyethylene terephthalate film. The characteristics of the obtained laminated polyester film are shown in Table 2-2.
Furthermore, on the second easy-adhesive layer of the film sample cut out to B4 size from the obtained laminated film, a UV curable composition having the following composition was diluted with methyl ethyl ketone so as to have a solid content concentration of 40% by mass, It was applied using a Meyer bar, immediately dried at 70 ° C. for 1 minute, and cured by irradiating with ultraviolet rays for 30 seconds with a high-pressure mercury lamp having an intensity of 80 W / cm to form a hard coat layer. The count of the Meyer bar was adjusted so that the hard coat layer thickness after curing was 5 μm.
(UV curable composition)
Pentaerythritol acrylate: 45% by weight
N-methylolacrylamide: 40% by weight
N-vinylpyrrolidone: 10% by weight
1-hydroxycyclohexyl phenyl ketone: 5% by weight
Table 2-2 shows the interference spots and adhesion results of the hard coat film on which the hard coat layer was laminated.

Below, the reference example which employ | adopted the copolyester resin 2 as a copolyester resin of a 2nd easily bonding layer is shown.
[Reference Examples 3-1 to 3-10, Reference Comparative Examples 3-1 to 3-9]
As for the thickness of the 2nd easily bonding layer obtained after extending | stretching the aqueous coating liquid whose solid content consists of a composition shown to Table 3-1 and 3-2 and whose solid content concentration is 10 mass% as shown in Table 3-3. A laminated film having a second easy-adhesion layer on both surfaces of a biaxially oriented polyethylene terephthalate film having a thickness of 125 μm was obtained in the same manner as in Reference Example 2-1, except that the film was uniformly applied with a roll coater. The plane direction refractive index of the obtained laminated film was 1.66.
Furthermore, on the 2nd easily-adhesive layer of the film sample cut out to B4 size from the obtained laminated | multilayer film, the UV curable composition in the reference example 2-1 mentioned above is methyl ethyl ketone (MEK), ethyl acetate, toluene, Prepare 5 types of solvents diluted with isopropanol (IPA) and propylene glycol monomethyl ether acetate (PGMEA) to a solid content concentration of 40% by mass, and apply each using a Meyer bar. Immediately after drying at 70 ° C. for 1 minute, a hard coat layer was formed by irradiating with a high-pressure mercury lamp with an intensity of 80 W / cm for 30 seconds to cure with ultraviolet rays. The count of the Meyer bar was adjusted so that the hard coat layer thickness after curing was 5 μm.
Table 3-3 shows the interference spots and adhesion results of the hard coat film on which the hard coat layer was laminated.

Below, the reference example which employ | adopted the copolyester resin 1 as a copolyester resin of a 2nd easily bonding layer and employ | adopted the crosslinkable addition polymer as a crosslinking agent is shown.
[Production Example 4-1: Crosslinkable addition polymer 1]
According to the method described in Production Examples 1 to 3 of JP-A-63-37167, the production was carried out as follows. That is, in a four-necked flask, 3 parts of sodium lauryl sulfonate as a surfactant and 181 parts of ion-exchanged water were charged and heated to 60 ° C. in a nitrogen stream, and then 0.5 part of ammonium persulfate as a polymerization initiator. Then, 0.2 part of sodium hydrogen nitrite was added, and a mixture of 30.0 parts of methyl methacrylate, 66.6 parts of 2-isopropenyl-2-oxazoline, and 8.5 parts of methacrylamide was further added. It was added dropwise while adjusting the liquid temperature to 60 to 70 ° C. over time. The reaction was continued with stirring while maintaining the same temperature range for 2 hours after the completion of the dropping, and then cooled to obtain an aqueous dispersion having a solid content of 35%.
The content of 2-isopropenyl-2-oxazoline unit (described as “oxazoline” in the table) and the content of polyethylene oxide (n = 10) methacrylic acid unit (“polyalkylene” in the table) in the resulting crosslinkable addition polymer Oxide ”was as shown in Tables 4-1 and 4-2. In the above, “part” represents “part by mass”.
[Production Examples 4-2 to 4-9: Crosslinkable addition polymers 2 to 9]
By appropriately changing the amount of raw material charged, the content of 2-isopropenyl-2-oxazoline units and the content of polyethylene oxide (n = 10) methacrylic acid units as shown in Tables 4-1 and 4-2 Some crosslinkable addition polymers 2 to 9 were obtained. In addition, polyethylene oxide (n = 10) methacrylic acid was used as a raw material (monomer) for constituting a polyethylene oxide (n = 10) methacrylic acid unit. The amount of these units increased or decreased is the total amount of methyl methacrylate units and methacrylamide units while maintaining the ratio of methyl methacrylate units: methacrylamide units = 3: 1 (molar ratio). Was adjusted by increasing or decreasing.
[Reference Examples 4-1 to 4-16, Reference Comparative Examples 4-1 to 4-7]
A roll coater is used so that the thickness of the second easy-adhesion layer obtained after stretching the aqueous coating liquid having a solid content of 10% by mass having a composition shown in Tables 4-1 and 4-2. A laminated polyester film having a second easy-adhesion layer on both sides of a 125 μm-thick biaxially oriented polyethylene terephthalate film was obtained in the same manner as in Reference Example 2-1, except that it was uniformly applied. The characteristics of the obtained laminated polyester film are shown in Tables 4-1 and 4-2.
Furthermore, a hard coat layer was formed in the same manner as in Reference Example 2-1, using the obtained laminated film. The count of the Meyer bar was adjusted so that the hard coat layer thickness after curing was 5 μm. Tables 4-1 and 4-2 show the results of interference spots and adhesiveness of the hard coat film on which the hard coat layer was laminated.

Below, the reference example which employ | adopted the copolyester resin 3 as a copolyester resin of a 2nd easily bonding layer is shown.
[Reference Examples 5-1 to 5-12, Reference Comparative Examples 5-1 to 5-6]
A roll coater is used so that the thickness of the second easy-adhesion layer obtained after stretching an aqueous coating liquid having a solid content of 10% by mass, comprising the composition shown in Tables 5-1 and 5-2, after stretching. A laminated polyester film having a second easy-adhesion layer on both sides of a 125 μm-thick biaxially oriented polyethylene terephthalate film was obtained in the same manner as in Reference Example 2-1, except that it was uniformly applied. The characteristics of the obtained laminated polyester film are shown in Tables 5-1 and 5-2.
Furthermore, a hard coat layer was formed in the same manner as in Reference Example 2-1, using the obtained laminated film. The count of the Meyer bar was adjusted so that the hard coat layer thickness after curing was 5 μm. Tables 5-1 and 5-2 show the results of interference spots and adhesiveness of the hard coat film on which the hard coat layer was laminated.

In Tables 2-1 to 5-2, NDCA is 2,6-naphthalenedicarboxylic acid component, TA is terephthalic acid component, IA is isophthalic acid component, NSIA is 5-sodium sulfoisophthalic acid component, C4G is tetramethylene glycol component, C8G is an octamethylene glycol component, BPA-4 is a bisphenol A ethylene oxide 4-mol adduct component (New Paul BPE-40) manufactured by Sanyo Chemical Industries, and BPA-23P is a bisphenol A propylene oxide adduct manufactured by Sanyo Chemical Industries. The component (Newpol BPE-23), BPEF means 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene component, and EG means ethylene glycol.
Moreover, as an oxazoline crosslinking agent (trade name Epocross WS-700 manufactured by Nippon Shokubai Co., Ltd.) as the crosslinking agent, silica acrylic composite fine particles (average particle diameter: 250 nm) (trade name Soriostar manufactured by Nippon Shokubai Co., Ltd.), and particle 2 are used. Used silica filler (50 nm) (trade name Snowtex manufactured by Nissan Chemical Co., Ltd.), and polyoxyethylene (n = 7) lauryl ether (trade name NAROACTY N-70, manufactured by Sanyo Chemical Industries, Ltd.) was used as the surfactant. .
IV in the table represents the intrinsic viscosity measured under conditions of o-chlorophenol and 35 ° C.
[Examples 6-1 to 6-4]
In the production of the polyester film of Example 1-1, when the coating liquid A for forming the first easy-adhesion layer is applied to one side of the film, the coating for forming the second easy-adhesion layer on the other side As a liquid, the thickness of the 2nd easily bonding layer obtained after extending | stretching the aqueous coating liquid of solid content concentration 10 mass% which consists of a composition shown to the reference Example 2-2 of Table 2-1 will be 75 nm. A biaxially oriented polyester film having a first easy-adhesion layer on one side and a second easy-adhesion layer on the other side, as in Example 1-1, except that it was uniformly applied by a roll coater The laminated body and transparent conductive film used were obtained as Example 6-1.
In the same manner, in Examples 1-2, 1-3, and 1-4, an aqueous coating having a solid content concentration of 10% by mass having a solid content of the composition shown in Reference Example 2-2 in Table 2-1 on the other surface. The liquid was apply | coated and the biaxially-oriented polyester film as Example 6-2, 6-3, and 6-4, the laminated body using the same, and a transparent conductive film were obtained, respectively.
About the obtained laminated body, evaluation which concerns on a 1st easily bonding layer was performed like Example 1-1. Moreover, about the obtained laminated body, evaluation which concerns on a 2nd easily bonding layer was performed like reference Example 2-2. The hard coat layer was formed on the second easy adhesion layer in the same manner as in Reference Example 2-2. The evaluation results are shown in Table 6.

[Examples 7-1 to 7-4]
In the production of the polyester film of Example 1-1, when the coating liquid A for forming the first easy-adhesion layer is applied to one side of the film, the coating for forming the second easy-adhesion layer on the other side As the liquid, an aqueous coating liquid having a solid content of 10% by mass having the composition shown in the coating liquid 3-1 in Table 3-2 is obtained as the second obtained after stretching in the same manner as in Reference Example 3-1. Except for uniformly coating with a roll coater so that the thickness of the easy-adhesion layer is 70 nm, as in Example 1-1, the first easy-adhesion layer is provided on one side and the second easy-adhesion layer is provided on the other side. A biaxially oriented polyester film, a laminate using the biaxially oriented polyester film, and a transparent conductive film were obtained as Example 7-1.
Similarly, in Examples 1-2, 1-3, and 1-4, an aqueous coating solution having a solid content concentration of 10% by mass on the other surface, the solid content having the composition shown in coating solution 3-1 of Table 3-2. Were applied to obtain biaxially oriented polyester films as Examples 7-2, 7-3, and 7-4, and laminates and transparent conductive films using the biaxially oriented polyester films, respectively.
About the obtained laminated body, evaluation which concerns on a 1st easily bonding layer was performed like Example 1-1. Moreover, the evaluation which concerns on a 2nd easily bonding layer was performed about the obtained laminated body similarly to Reference Example 3-1. The hard coat layer was formed on the second easy adhesion layer in the same manner as in Reference Example 3-1. Table 7 shows the evaluation results.

[Examples 8-1 to 8-4]
In the production of the polyester film of Example 1-1, when the coating liquid A for forming the first easy-adhesion layer is applied to one side of the film, the coating for forming the second easy-adhesion layer on the other side As a liquid, the thickness of the 2nd easily bonding layer obtained after extending | stretching the aqueous coating liquid of solid content concentration 10 mass% which consists of a composition shown to the reference example 4-2 of Table 4-1 will be 75 nm. A biaxially oriented polyester film having a first easy-adhesion layer on one side and a second easy-adhesion layer on the other side, as in Example 1-1, except that it was uniformly applied by a roll coater The laminated body and transparent conductive film used were obtained as Example 8-1.
Similarly, in Examples 1-2, 1-3, and 1-4, an aqueous coating having a solid content concentration of 10% by mass having the composition shown in Reference Example 4-2 in Table 4-1 on the other surface. The liquid was apply | coated and the biaxially-oriented polyester film as Example 8-2, 8-3, and 8-4, the laminated body using the same, and a transparent conductive film were obtained, respectively.
About the obtained laminated body, evaluation which concerns on a 1st easily bonding layer was performed like Example 1-1. Moreover, the evaluation which concerns on a 2nd easily bonding layer was performed about the obtained laminated body similarly to Reference Example 4-2. In addition, the hard-coat layer was formed on the 2nd easily bonding layer like the reference example 4-2. The evaluation results are shown in Table 8.

[Examples 9-1 to 9-4]
In the production of the polyester film of Example 1-1, when the coating liquid A for forming the first easy-adhesion layer is applied to one side of the film, the coating for forming the second easy-adhesion layer on the other side As a liquid, the thickness of the 2nd easily bonding layer obtained after extending | stretching the aqueous coating liquid of solid content concentration 10 mass% which consists of a composition shown to Reference Example 5-1 of Table 5-1 will be 75 nm. A biaxially oriented polyester film having a first easy-adhesion layer on one side and a second easy-adhesion layer on the other side, as in Example 1-1, except that it was uniformly applied by a roll coater The laminated body and transparent conductive film used were obtained as Example 9-1.
Similarly, in Examples 1-2, 1-3, and 1-4, an aqueous coating having a solid content concentration of 10% by mass on the other surface, the solid content having the composition shown in Reference Example 5-1 in Table 5-1. The liquid was apply | coated and the biaxially-oriented polyester film as Example 9-2, 9-3, 9-4, the laminated body using the same, and a transparent conductive film were obtained, respectively.
About the obtained laminated body, evaluation which concerns on a 1st easily bonding layer was performed like Example 1-1. Moreover, the evaluation which concerns on a 2nd easily bonding layer was performed about the obtained laminated body similarly to Reference Example 5-1. The hard coat layer was formed on the second easy adhesion layer in the same manner as in Reference Example 5-1. Table 9 shows the evaluation results.

The invention's effect
ADVANTAGE OF THE INVENTION According to this invention, the laminated body for transparent conductive film base materials which made the outstanding index matching characteristic and favorable adhesiveness compatible can be provided. Due to the above effects, when the laminate of the present invention is adopted as a substrate of a transparent conductive film having a patterned transparent conductive layer, a good bone-inhibiting effect can be realized, and a polyester film and an optical adjustment layer Adhesiveness with (especially high refractive index layer) can be made excellent.
In addition, the laminated polyester film which is a preferred embodiment of the present invention is provided with an easy-adhesion layer using a specific copolymer polyester such as the above-described copolymer polyester resin 1, so that even an in-line coating which is usually employed is stretched. Since it is difficult to cause easy adhesion layer cracking in the process, for example, it has excellent adhesion to a functional layer such as a hard coat layer, and also has a feature that light interference spots (color spots) hardly occur. Therefore, it can be particularly suitably used as an easily adhesive polyester film for optics.
The laminated film, which is another preferred embodiment of the present invention, has the characteristics that the swelling ratio of the easy-adhesion layer is in a specific range, so that interference spots (color spots) hardly occur and the adhesiveness is excellent. Therefore, it can be suitably used as an easily adhesive film for optics.
The laminated polyester film which is another preferred embodiment of the present invention is provided with an easy-adhesion layer using a specific cross-linking agent such as a specific copolymer polyester and the above cross-linkable polymer, and is therefore usually used in-line. Even in coating, easy adhesion layer cracking in the stretching process is unlikely to occur, so it has excellent adhesion to functional layers such as hard coat layers, especially in wet and heat environments, and light interference spots (color spots) ) Is also unlikely to occur. Therefore, it can be particularly suitably used as an easily adhesive polyester film for optics.
The laminated polyester film which is another preferred embodiment of the present invention is provided with an easy-adhesion layer using a specific copolymerized polyester such as the above-described copolymerized polyester 3. Therefore, even in the in-line coating which is usually employed, the stretching step Easy-to-adhesive layer cracking is unlikely to occur, so it has excellent adhesion to functional layers such as hard coat layers, especially in wet heat environments, and light interference spots (color spots) may also occur. It has the characteristics of wanting. Therefore, it can be particularly suitably used as an easily adhesive polyester film for optics.

The laminate of the present invention can be suitably used as a substrate for a transparent conductive film having a patterned transparent conductive layer. Thereby, the electrode by which the bone appearance was suppressed can be obtained and the electrostatic capacitance type touch panel excellent in visibility can be obtained.

Claims

A laminated body having a first easy-adhesion layer and an optical adjustment layer in this order on at least one surface of the polyester film, wherein the first easy-adhesion layer is 50 masses based on the mass of the first easy-adhesion layer. %, A refractive index of 1.60 to 1.65, and a thickness of 8 to 30 nm.
The average refractive index in the plane direction of the polyester film is 1.60 to 1.70, and the optical adjustment layer is composed of a high refractive index layer disposed on the first easy adhesion layer side and a low refractive index layer thereon, The laminate for a transparent conductive film substrate according to claim 1, wherein the refractive index layer has a refractive index of 1.60 to 1.80, and the low refractive index layer has a refractive index of 1.40 to 1.60. .
The laminate for a transparent conductive film substrate according to claim 1 or 2, wherein the first easy-adhesion layer contains metal oxide particles having a refractive index of 1.7 to 3.0.
The laminate for a transparent conductive film substrate according to any one of claims 1 to 3, wherein the refractive index of the polyester resin in the first easy-adhesion layer is 1.58 to 1.65.
The polyester resin in the first easy-adhesion layer is a copolymer polyester resin containing a naphthalene dicarboxylic acid component and / or a diol component having a fluorene structure as a copolymer component, according to any one of claims 1 to 4. Laminated body for transparent conductive film substrate.
A transparent conductive film having a patterned transparent conductive layer having a refractive index of 1.9 to 2.3 on the optical adjustment layer in the laminate according to any one of claims 1 to 5.
The laminate according to any one of claims 1 to 6, wherein the polyester film has a first easy-adhesion layer and an optical adjustment layer in this order on one side, and a second easy-adhesion layer on the other side. A laminate in which the second easy-adhesion layer contains 70% by mass or more of the following copolyester based on the mass of the second easy-adhesion layer.
Copolyester:
(A1) 60-90 mol% of naphthalenedicarboxylic acid component,
(B1) 0 to 40 mol% of the alkylene dicarboxylic acid component having 6 to 12 carbon atoms, 0 to 50 mol% of the alkylene glycol component having 4 to 10 carbon atoms, and the total of the alkylene dicarboxylic acid component and the alkylene glycol component is 15 Copolyester containing ~ 50 mol% and (C1) 5 mol% or more and less than 20 mol% of a glycol component having a fluorene structure represented by the following formula (I).
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)

(R 1 is an alkylene group having 2 to 4 carbon atoms, R 2 , R 3 , R 4 , and R 5 are hydrogen, an alkyl group having 1 to 4 carbon atoms, an aryl group, or an aralkyl group. Or different.)
The laminate according to claim 7, wherein the second easy-adhesion layer contains 1 to 30% by mass of the following cross-linkable addition polymer based on the mass of the second easy-adhesion layer.
Crosslinkable addition polymer:
(X1) containing 10 to 80 mol% of an addition polymerizable oxazoline group-containing monomer unit,
(Y1) A crosslinkable addition polymer having an addition polymerizable polyalkylene oxide group-containing monomer unit content of 5 mol% or less.
(The above mol% is a value based on 100 mol% of all monomer units of the crosslinkable addition polymer.)
The copolymerized polyester further contains (F1) a dicarboxylic acid component having a sulfonate group in an amount of 0.1 to 5 mol%.
(However, the above mol% is a value with respect to 100 mol% of all dicarboxylic acid components of the copolyester.)
The laminated body of Claim 7 containing.
The laminate according to any one of claims 1 to 6, wherein the polyester film has a first easy-adhesion layer and an optical adjustment layer in this order on one side of the polyester film, and the polyester film has an average refractive index in the plane direction of 1. .63 to 1.68, the refractive index is 1.58 to 1.64 on the other surface, the swelling ratio obtained by the following method is 130 to 200% in any solvent, and the thickness is 50 to 100 nm. The laminated body which has a certain 2nd easily bonding layer.
Swelling rate:
On the second easy-adhesion layer of the laminate, a coating solution (solid content concentration 40% by mass) obtained by diluting the following UV curable composition with a solvent (methyl ethyl ketone, ethyl acetate, toluene, isopropanol or propylene glycol monomethyl ether) was applied. The hard coat layer having a thickness of 5 μm is formed by drying and curing, the thickness dh of the second easy-adhesion layer after forming the hard coat layer, and the thickness d0 of the second easy-adhesion layer before forming the hard coat layer From the above, the swelling ratio E (%) = value obtained as dh / d0 × 100.
UV curable composition:
Pentaerythritol acrylate: 45% by mass
N-methylolacrylamide: 40% by mass
N-vinylpyrrolidone: 10% by mass
1-hydroxycyclohexyl phenyl ketone: 5% by mass