JP6642635B2 - Manufacturing method of laminated polyester film - Google Patents

Description

  The present invention relates to a laminated polyester film, for example, when transporting a resin plate, a metal plate, etc., as a surface protective film and the like for preventing scratches and dirt adhesion during storage and processing, etc. The present invention relates to a laminated polyester film having excellent mechanical strength and heat resistance, and having good adhesive properties and permeability.

  Conventionally, prevention of scratches and dirt adhesion during transportation, storage and processing of resin plates, metal plates and glass plates, etc., and damage during processing of components used in electronic related fields such as liquid crystal panels and polarizing plates A wide range of surface protection films are used for prevention, dust and dirt adhesion prevention, dirt adhesion prevention during transportation and storage of automobiles, protection of automobile coating from acid rain, protection during plating and etching of flexible printed circuit boards, etc. It is used.

  These surface protective films, such as resin plate, metal plate and glass plate, during transport of various adherends, at the time of storage and processing, etc., have an appropriate adhesive force to the adherend, It is required that the surface of the adherend be protected by being adhered to the surface of the adherend, and that it be easily peeled off after the end of the purpose. In order to overcome these problems, proposals have been made to use a polyolefin-based film for surface protection (Patent Documents 1 and 2).

  However, since a polyolefin-based film is used as the surface protective film base material, it is not possible to remove a defect generally caused by a gel-like material or a degraded material caused by the film base material, which is generally called fisheye. For example, when inspecting an adherend in a state where the surface protective film is attached, there is a problem that an obstacle such as detection of a defect of the surface protective film occurs.

  In addition, as a substrate of the surface protective film, a film having a certain degree of mechanical strength is required so that the substrate is not stretched due to tension during various kinds of processing, such as when bonding to an adherend. However, polyolefin-based films generally have poor mechanical strength, and are disadvantageous in that they are unsuitable for high-tensile processing due to, for example, increasing the processing speed in order to emphasize productivity.

  Furthermore, even when the processing temperature is raised to improve the processing speed and various characteristics, the dimensional stability is poor because the polyolefin-based film is not excellent in heat shrinkage stability. Therefore, there is a demand for a film which has little thermal deformation even at high temperature processing and has excellent dimensional stability.

JP-A-5-98219 JP 2007-270005 A

  The present invention has been made in view of the above-mentioned circumstances, and the problem to be solved is to use it for various surface protection films, etc., to have less fish eyes, excellent mechanical strength and heat resistance, and to have good adhesive properties. It is to provide a laminated polyester film.

  The present inventor has conducted intensive studies in view of the above circumstances, and as a result, has found that the above-mentioned problems can be easily solved by using a laminated polyester film having a specific configuration, and has completed the present invention.

That is, the gist of the present invention is to provide, on one surface of a polyester film, an adhesive layer containing an acrylic resin having a glass transition point of 0 ° C. or less (excluding a fluoropolymer) and a film thickness of 10 μm or less , content tacky Chakusochu of a acrylic resin is 45 wt% or more, the polyester film surface of the pressure-sensitive adhesive layer opposite the minimum value of absolute reflectance in the wavelength range of 400~800nm is less than 4.0% a method for producing a laminated polyester film Ru provided with a functional layer is, an adhesive layer on one surface of a polyester film provided, after providing a functional layer on the polyester film surface opposite the adhesive layer, the adhesive layer and functions method for producing a laminated polyester film, which comprises stretching a layer with the polyester film, and on one surface of a polyester film, a glass transition temperature It is 0 ℃ or less, containing a polyester resin or urethane resin, thickness comprises an adhesive layer is 10μm or less, the content of the Po Riesuteru resin or urethane resin tacky Chakusochu 45 wt% or more, the viscosity polyester film surface on the side opposite to the wearing layer, a method for producing a laminated polyester film the minimum value of absolute reflectance Ru a function layer is less than 4.0% in the wavelength range of 400 to 800 nm, of the polyester film An adhesive layer is provided on one side, and after providing a functional layer on the polyester film surface opposite to the adhesive layer, the adhesive layer and the functional layer are stretched together with the polyester film. .

  According to the laminated polyester film of the present invention, as various surface protective films, it is possible to provide a film having less fish eyes, excellent mechanical strength and heat resistance, and having good adhesive properties and permeability. The value is high.

We believe that it is necessary to significantly change the base material of the base film in order to reduce fisheye, improve mechanical strength, and improve heat resistance, which are issues, and as a result of various studies, it is significantly different from the conventionally used polyolefin-based materials. It has been found that this can be achieved by using a polyester-based material. However, by greatly changing the material system of the base film, the adhesive properties have been significantly reduced, and it has become impossible to achieve with a general polyester film. Therefore, improvement was achieved by providing an adhesive layer on the base film, and the present invention was achieved.

  The polyester film may have a single-layer configuration or a multilayer configuration. In the case of a multi-layer structure, the surface layer and the inner layer, or both surface layers and each layer can be different polyester layers according to the purpose, and a multi-layer structure of two or more layers is provided, and each layer has a feature to achieve multi-functionality. Is preferred.

  The polyester used may be a homopolyester or a copolyester. In the case of a homopolyester, those obtained by polycondensing an aromatic dicarboxylic acid and an aliphatic glycol are preferred. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Typical polyesters include polyethylene terephthalate and the like. On the other hand, examples of the dicarboxylic acid component of the copolymerized polyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and oxycarboxylic acid (for example, p-oxybenzoic acid). One or two or more of them can be mentioned, and as the glycol component, one or two or more of ethylene glycol, diethylene glycol, propylene glycol, butanediol, 4-cyclohexanedimethanol, neopentyl glycol and the like can be mentioned.

  From the viewpoint of forming a film that can withstand various processing conditions, it is preferable that the mechanical strength and the heat resistance (dimensional stability by heating) are high, and for this purpose, it is sometimes preferable that the copolymer polyester component is small. Specifically, the proportion of the monomer forming the copolymerized polyester in the polyester film is usually in the range of 10 mol% or less, preferably 5 mol% or less, and more preferably produced as a by-product during homopolyester polymerization. It is a degree that contains less than 3 mol% of diether components. A more preferable form as the polyester is a film formed from polyethylene terephthalate or polyethylene naphthalate, which is obtained by polymerizing terephthalic acid and ethylene glycol, in consideration of mechanical strength and heat resistance. Considering ease of use and handling properties as uses such as a surface protection film, a film formed from polyethylene terephthalate is more preferable.

  The polymerization catalyst for the polyester is not particularly limited, and a conventionally known compound can be used. Examples thereof include an antimony compound, a titanium compound, a germanium compound, a manganese compound, an aluminum compound, a magnesium compound, and a calcium compound. Among them, antimony compounds are preferable because they are inexpensive, and titanium compounds and germanium compounds have high catalytic activity, can be polymerized in a small amount, and have a small amount of metal remaining in the film. Is preferred because the transparency is high. Further, since a germanium compound is expensive, it is more preferable to use a titanium compound.

  In the case of a polyester using a titanium compound, the titanium element content is usually 50 ppm or less, preferably 1 to 20 ppm, and more preferably 2 to 10 ppm. If the content of the titanium compound is too large, the degradation of the polyester may be promoted in the step of melt-extruding the polyester, and the film may have a strong yellow tint.If the content is too small, the polymerization efficiency is poor and the cost is low. Up and a film having sufficient strength may not be obtained. When a polyester made of a titanium compound is used, it is preferable to use a phosphorus compound to reduce the activity of the titanium compound for the purpose of suppressing deterioration in the step of melt extrusion. As the phosphorus compound, orthophosphoric acid is preferable in consideration of productivity and thermal stability of the polyester. The phosphorus element content is usually in the range of 1 to 300 ppm, preferably 3 to 200 ppm, more preferably 5 to 100 ppm, based on the amount of the polyester to be melt-extruded. If the content of the phosphorus compound is too large, it may cause gelation or foreign substances, and if the content is too small, the activity of the titanium compound cannot be sufficiently reduced, and the It may be a certain film.

  Particles can be incorporated into the polyester layer for the purpose of imparting lubricity, preventing scratching in each step, and improving blocking resistance. When blending the particles, the type of the blended particles is not particularly limited as long as the particles can impart lubricity, and specific examples include, for example, silica, calcium carbonate, magnesium carbonate, barium carbonate, and sulfuric acid. Examples include inorganic particles such as calcium, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, zirconium oxide, and titanium oxide; and organic particles such as acrylic resin, styrene resin, urea resin, phenol resin, epoxy resin, and benzoguanamine resin. Further, during the polyester production step, precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed can be used. Among these, silica particles and calcium carbonate particles are preferable because the effect is easily obtained with a small amount.

  The average particle size of the particles is usually 10 μm or less, preferably 0.01 to 5 μm, and more preferably 0.01 to 3 μm. When the average particle size exceeds 10 μm, there is a possibility that a problem due to a decrease in the transparency of the film may occur.

  Further, the content of the particles in the polyester layer cannot be unconditionally determined because it depends on the average particle size of the particles, but is usually 5% by weight or less, preferably 0.0003 to 3% by weight, and more preferably 0% by weight. 0.0005 to 1% by weight. When the content of the particles exceeds 5% by weight, there may be a case where problems such as falling off of the particles and lowering of the transparency of the film are caused. If there are no or few particles, the slip properties may be insufficient. Therefore, it may be necessary to improve the slip properties by, for example, putting particles in the adhesive layer.

The shape of the particles to be used is not particularly limited, and any of a spherical shape, a massive shape, a rod shape, a flat shape and the like may be used. There is no particular limitation on the hardness, specific gravity, color and the like.
These series of particles may be used in combination of two or more as necessary.

  The method for adding particles to the polyester layer is not particularly limited, and a conventionally known method can be employed. For example, it can be added at any stage of producing the polyester constituting each layer, but is preferably added after completion of the esterification or transesterification reaction.

In addition to the above-mentioned particles, conventionally known ultraviolet absorbers, antioxidants, antistatic agents, heat stabilizers, lubricants, dyes, pigments, and the like can be added to the polyester film, if necessary.

  The thickness of the polyester film is not particularly limited as long as it can be formed into a film, but is usually in the range of 2 to 350 μm, preferably 5 to 200 μm, and more preferably 8 to 75 μm.

  The production example of the film will be specifically described, but is not limited to the following production example, and a generally known film forming method can be adopted. Generally, a resin is melted, formed into a sheet, and stretched for the purpose of increasing the strength, and a film is formed. For example, when manufacturing a biaxially stretched polyester film, first, a polyester raw material is melt-extruded from a die using an extruder, and the molten sheet is cooled and solidified by a cooling roll to obtain an unstretched sheet. In this case, in order to improve the flatness of the sheet, it is preferable to increase the adhesion between the sheet and the rotary cooling drum, and an electrostatic application adhesion method or a liquid application adhesion method is preferably employed. Next, the obtained unstretched sheet is stretched in one direction by a roll or tenter type stretching machine. The stretching temperature is usually from 70 to 120 ° C, preferably from 80 to 110 ° C, and the stretching ratio is usually from 2.5 to 7 times, preferably from 3.0 to 6 times. Next, the film is stretched in a direction orthogonal to the stretching direction of the first step at a temperature of usually 70 to 170 ° C. and a stretching ratio of usually 2.5 to 7 times, preferably 3.0 to 6 times. Subsequently, a heat treatment is usually performed at a temperature of 180 to 270 ° C. under tension or relaxation within 30% to obtain a biaxially oriented film. In the above-mentioned stretching, a method of performing unidirectional stretching in two or more steps may be employed. In that case, it is preferable that the stretching is performed so that the stretching ratios in the two directions finally fall within the above ranges.

  For the production of a polyester film constituting a laminated polyester film, a simultaneous biaxial stretching method can be employed. The simultaneous biaxial stretching method is a method of simultaneously stretching the unstretched sheet in the machine direction and the width direction in a state where the temperature is controlled at 70 to 120 ° C., preferably 80 to 110 ° C., and stretching the unstretched sheet. Is usually 4 to 50 times, preferably 7 to 35 times, more preferably 10 to 25 times in area magnification. Subsequently, heat treatment is performed at a temperature of 180 to 270 ° C. under tension or relaxation within 30% to obtain a stretched oriented film. As for the simultaneous biaxial stretching apparatus that employs the above-described stretching method, a conventionally known stretching method such as a screw method, a pantograph method, or a linear drive method can be employed.

  Next, formation of the adhesive layer constituting the laminated polyester film will be described. Examples of the method for forming the adhesive layer include methods such as coating, transfer, and lamination. Considering the ease of forming the adhesive layer, it is preferable to form the layer by coating.

  As a method by coating, it may be provided by in-line coating performed in the process of film production, or may be provided by off-line coating, in which a once-produced film is coated outside the system. More preferably, it is formed by in-line coating.

  Specifically, in-line coating is a method in which coating is performed at any stage from melt extrusion of a resin forming a film to stretching, heat setting and winding. Usually, it is coated on any of an unstretched sheet obtained by melting and quenching, a stretched uniaxially stretched film, a biaxially stretched film before heat setting, and a film after heat setting and before winding. Although not limited to the following, for example, in successive biaxial stretching, a method of coating a uniaxially stretched film stretched in the longitudinal direction (longitudinal direction) and then stretching it in the transverse direction is excellent. According to such a method, there is an advantage in manufacturing cost because film formation and formation of the adhesive layer can be performed at the same time, and in order to perform stretching after coating, the thickness of the adhesive layer can be changed by the stretching ratio. In addition, thin film coating can be performed more easily than offline coating.

  In addition, by providing the adhesive layer on the film before stretching, the adhesive layer can be stretched together with the base film, whereby the adhesive layer can be firmly adhered to the base film. Furthermore, in the production of a biaxially stretched polyester film, the film can be constrained in the vertical and horizontal directions by stretching while gripping the end of the film with a clip or the like. High temperature can be applied while maintaining the properties.

  Therefore, since the heat treatment performed after coating can be performed at a high temperature that cannot be achieved by other methods, the film forming property of the adhesive layer is improved, and the adhesive layer and the base film can be more firmly adhered. Further, a strong adhesive layer can be obtained. In particular, it is very effective for reacting a crosslinking agent.

  According to the above-described process using in-line coating, the film size does not greatly change depending on the presence or absence of the adhesive layer, and the risk of scratching and adhesion of foreign substances does not change significantly depending on whether the adhesive layer is formed. This is a great advantage over off-line coating performed one extra step. Furthermore, as a result of various studies, it has been found that in-line coating has an advantage that adhesive residue, which is a migration of components of the adhesive layer when the film of the present invention is bonded to an adherend, can be reduced. Was. It is considered that this is because heat treatment can be performed at a high temperature that cannot be obtained by off-line coating, and the adhesive layer and the base film are more firmly adhered to each other.

  In the present invention, a glass transition point containing a resin having a temperature of 0 ° C. or less, having a pressure-sensitive adhesive layer having a thickness of 10 μm or less, on the polyester film surface opposite to the pressure-sensitive adhesive layer, the wavelength of 400 to 800 nm. It is indispensable to have a functional layer in which the minimum value of the absolute reflectance is less than 4.0%.

  Although a general adhesive layer has a thick film thickness exceeding 10 μm, in the present invention, the film thickness of the adhesive layer is set to a thin range of 10 μm or less. When the film is cut and bonded to an adherend such as a polarizing plate, the protrusion of the pressure-sensitive adhesive in the pressure-sensitive adhesive layer can be minimized, and the absolute amount of the pressure-sensitive adhesive layer present on the film can be reduced. It was also found that the amount was small, and that the components of the adhesive layer were transferred to the adherend, and that it was also effective in reducing adhesive residue.

  As the resin having a glass transition point of 0 ° C. or lower, a conventionally known resin can be used. Specific examples of the resin include a polyester resin, an acrylic resin, a urethane resin, and a polyvinyl resin (polyvinyl alcohol, vinyl chloride-vinyl acetate copolymer, and the like). , An acrylic resin and a urethane resin are preferable, and a polyester resin and an acrylic resin are more preferable in view of the strength of the adhesive property, and a polyester resin is more preferable because of high adhesive strength to various adherends. When considering the reusability of the film, a polyester resin or an acrylic resin is preferable, and when the substrate is a polyester film, the polyester resin is used when considering the adhesion to the substrate, and the change with time is small. Acrylic resins are most preferred when considered. Furthermore, in consideration of the migration of the components of the pressure-sensitive adhesive layer to the adherend, it has been found that an acrylic resin has less migration and is more preferable than a polyester resin.

  The polyester resin includes, for example, those composed of the following polyvalent carboxylic acids and polyvalent hydroxy compounds as main constituent components. That is, polycarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 4,4′-diphenyldicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and 2,6 -Naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2-potassium sulfoterephthalic acid, 5-sodium sulfoisophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, glutar Acid, succinic acid, trimellitic acid, trimesic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, p-hydroxybenzoic acid, monopotassium trimellitic acid and their ester-forming derivatives can be used. , Polyhydric hydroxy compound, ethylene Recol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 2-methyl-1,5-pentanedio- , Neopentyl glycol, 1,4-cyclohexanedimethanol, p-xylylene glycol, bisphenol A-ethylene glycol adduct, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol , Polytetramethylene glycol, polytetramethylene oxide glycol, dimethylolpropionic acid, glycerin, trimethylolpropane, sodium dimethylolethylsulfonate, potassium dimethylolpropionate, and the like. One or more of these compounds may be appropriately selected, and a polyester resin may be synthesized by a conventional polycondensation reaction.

  Among these, it is preferable that an aliphatic polycarboxylic acid or an aliphatic polyhydroxy compound is contained in the constituent component in order to lower the glass transition point to 0 ° C. or lower. Generally, a polyester resin is composed of an aromatic polycarboxylic acid and a polyvalent hydroxy compound including an aliphatic compound. It is effective to contain a carboxylic acid. From the viewpoint of lowering the glass transition point, the aliphatic polycarboxylic acid preferably has a long carbon number, and usually has a carbon number of 6 or more (adipic acid), preferably 8 or more, more preferably 10 or more. And the upper limit of the preferred range is 20.

  From the viewpoint of improving the adhesive properties, the content of the aliphatic polycarboxylic acid in the acid component in the polyester resin is usually 2 mol% or more, preferably 4 mol% or more, more preferably 6 mol% or more. It is particularly preferably at least 10 mol%, and the upper limit of the preferable range is 50 mol%.

  In order to lower the glass transition point of the aliphatic polyhydroxy compound, the number of carbon atoms is preferably 4 or more (butanediol), and the content of the hydroxy component in the polyester resin is preferably 10 mol. % Or more, more preferably 30 mol% or more.

  Considering suitability for in-line coating, it is preferable to use an aqueous system, and for that purpose, it is preferable that a sulfonic acid, a sulfonic acid salt, a carboxylic acid, and a carboxylic acid salt, which are hydrophilic functional groups, are contained in the polyester resin. Particularly, sulfonic acid and sulfonic acid salt are preferable, and sulfonic acid salt is particularly preferable, in terms of good dispersibility in water. Among sulfonic acid salts, metal sulfonic acid salts are more preferable.

  When the above sulfonic acid, sulfonic acid salt, carboxylic acid, or carboxylic acid salt is used, the content in the acid component in the polyester resin is usually 0.1 to 10 mol%, preferably 0.2 to 8 mol%. Range. When used in the above range, the dispersibility in water becomes good.

  In addition, considering the appearance of the coating in in-line coating, adhesion and blocking to the film, and further reducing migration to the adherend when used as a surface protection film (adhesive residue), as an acid component in the polyester resin, It is preferable to contain a certain amount of aromatic polycarboxylic acid. The proportion of the aromatic polycarboxylic acid in the acid component in the polyester resin is usually at least 30 mol%, preferably at least 50 mol%, more preferably at least 60 mol%, and the upper limit of the preferable range is 98 mol%. Mol%. Further, among aromatic polyvalent carboxylic acids, a benzene ring structure such as terephthalic acid or isophthalic acid is more preferable than a naphthalene ring structure from the viewpoint of adhesive properties. In order to further improve the adhesive properties, it is more preferable to use two or more aromatic polycarboxylic acids in combination.

  The glass transition point of the polyester resin for improving the adhesive property is essential to be 0 ° C or lower, preferably -10 ° C or lower, more preferably -20 ° C or lower, and the lower limit of the preferable range is- 60 ° C. By using it in the above range, it becomes easy to obtain a film having optimal adhesive properties.

The acrylic resin is a polymer composed of a polymerizable monomer containing an acrylic or methacrylic monomer (hereinafter, acryl and methacryl may be abbreviated as (meth) acryl in some cases). These may be any of a homopolymer or a copolymer, and a copolymer with a polymerizable monomer other than an acrylic or methacrylic monomer.
Further, a copolymer of such a polymer and another polymer (for example, polyester, polyurethane or the like) is also included. For example, it is a block copolymer or a graft copolymer. Alternatively, a polymer (polymer mixture in some cases) obtained by polymerizing a polymerizable monomer in a polyester solution or a polyester dispersion is also included. Similarly, a polymer (polymer mixture in some cases) obtained by polymerizing a polymerizable monomer in a polyurethane solution or a polyurethane dispersion is also included. Similarly, a polymer (polymer mixture in some cases) obtained by polymerizing a polymerizable monomer in another polymer solution or dispersion is also included. However, in consideration of the adhesive properties and adhesive residue on the adherend, it should not contain other polymers such as polyester and polyurethane (polymerizable monomers containing carbon-carbon double bonds (both homopolymers and copolymers). (Meth) acrylic resin) composed only of (Possible).

  The polymerizable monomer is not particularly limited, but particularly typical compounds include, for example, various carboxyl groups such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and citraconic acid. Monomers and their salts; such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monobutylhydrokyl fumarate, monobutylhydroxyitaconate Various hydroxyl group-containing monomers; various types such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and lauryl (meth) acrylate (Meta) acri Acid esters; various nitrogen-containing compounds such as (meth) acrylamide, diacetone acrylamide, N-methylolacrylamide or (meth) acrylonitrile; various styrene derivatives such as styrene, α-methylstyrene, divinylbenzene, and vinyltoluene Various vinyl esters such as vinylpropionate and vinyl acetate; various silicon-containing polymerizable monomers such as γ-methacryloxypropyltrimethoxysilane and vinyltrimethoxysilane; phosphorus-containing vinyl monomers; Various vinyl halides such as vinyl and viridene chloride; and various conjugated dienes such as butadiene.

  In order to lower the glass transition point to 0 ° C. or lower, it is necessary to use a (meth) acrylic system having a glass transition point of the homopolymer of 0 ° C. or lower, for example, ethyl acrylate (glass transition point: −22 ° C.) n-propyl acrylate (glass transition point: -37 ° C), isopropyl acrylate (glass transition point: -5 ° C), normal butyl acrylate (glass transition point: -55 ° C), normal hexyl acrylate (glass transition point: -57) ° C), 2-ethylhexyl acrylate (glass transition point: -70 ° C), normal octyl acrylate (glass transition point: -65 ° C), isooctyl acrylate (glass transition point: -83 ° C), normal nonyl acrylate (glass Transition point: -63 ° C), normal nonyl methacrylate (glass transition point: -35 ° C), isono Ruacrylate (glass transition point: -82 ° C), normal decyl acrylate (glass transition point: -70 ° C), normal decyl methacrylate (glass transition point: -45 ° C), isodecyl acrylate (glass transition point: -55 ° C) , Isodecyl methacrylate (glass transition point: -41 ° C), lauryl acrylate (glass transition point: -30 ° C), lauryl methacrylate (glass transition point: -65 ° C), tridecyl acrylate (glass transition point: -75 ° C) ), Tridecyl methacrylate (glass transition point: -46 ° C), isomistyryl acrylate (glass transition point: -56 ° C), 2-hydroxyethyl acrylate (glass transition point: -15 ° C), and the like.

  Among the above, in order to improve the adhesive property, the carbon number of the alkyl group is usually in the range of 4 or more, preferably in the range of 4 to 30, more preferably in the range of 4 to 20, and particularly preferably in the range of 4 to 14. Is employed. (Meth) acrylic resins containing normal butyl acrylate and 2-ethylhexyl acrylate, which are industrially mass-produced and contain normal butyl acrylate and 2-ethylhexyl acrylate, are most suitable from the viewpoint of handleability and supply stability.

  The content in the (meth) acrylic resin of the (meth) acrylate unit having an alkyl group having 4 or more carbon atoms at the ester terminal is usually 20% by weight or more, preferably 35 to 99% by weight, and more preferably 50 to 98% by weight. %, Particularly preferably in the range from 65 to 95% by weight, most preferably from 75 to 90% by weight. The higher the content of the (meth) acrylate unit having an alkyl group having 4 or more carbon atoms at the ester terminal, the stronger the adhesive properties. Conversely, if the content is too small, the adhesive strength may not be sufficient.

  In the (meth) acrylic resin, the content of the (meth) acrylate unit having a homopolymer having a glass transition point of 0 ° C. or less and an alkyl group having less than 4 carbon atoms at an ester terminal is usually 50% by weight or less. , Preferably 40% by weight or less, more preferably 30% by weight or less. When used in the above range, good adhesive properties are obtained.

In addition, from the viewpoint that transfer of the adhesive component to the adherend can be reduced, among the above, a compound having 2 or less carbon atoms at the ester terminal or a compound having a cyclic structure is preferable, and further preferable. Is a compound having 1 carbon atom or an aromatic compound.
Specific examples include methyl methacrylate, acrylonitrile, styrene, and cyclohexyl acrylate as preferred compounds.

  The content of the compound unit having 2 or less carbon atoms at the ester terminal in the (meth) acrylic resin is usually 50% by weight or less, preferably 1 to 40% by weight, more preferably 3 to 30% by weight. %, Particularly preferably in the range from 5 to 20% by weight. The smaller the content of the unit is, it is possible to impart an appropriate range of adhesive properties without significantly lowering the adhesive properties, and conversely, the greater the content, the greater the adherence to the adherend It becomes possible to reduce the migration of the adhesive component. Therefore, within the above range, it is easy to achieve the two objects of the adhesive property and the migration reduction.

  The content of the compound unit having a cyclic structure in the (meth) acrylic resin is usually 50% by weight or less, preferably 1 to 45% by weight, and more preferably 5 to 40% by weight. The smaller the content of the unit is, it is possible to impart an appropriate range of adhesive properties without significantly lowering the adhesive properties, and conversely, the greater the content, the greater the adherence to the adherend It becomes possible to reduce the migration of the adhesive component. Therefore, within the above range, it is easy to achieve the two objects of the adhesive property and the migration reduction.

  From the viewpoint of the adhesive properties, the content of the monomer having a glass transition point of 0 ° C. or less as a monomer constituting the (meth) acrylic resin is usually 30% by weight or more as a ratio to the entire (meth) acrylic resin. , Preferably at least 45% by weight, more preferably at least 60% by weight, particularly preferably at least 70% by weight. The upper limit of the preferred range is 99% by weight. When used in this range, good adhesive properties are easily obtained.

  Further, the glass transition point of a monomer having a glass transition point of 0 ° C. or lower for improving the adhesive property is usually −20 ° C. or lower, preferably −30 ° C. or lower, more preferably −40 ° C. or lower, particularly It is preferably -50 ° C or lower, and the lower limit of the preferred range is -100 ° C. By using in this range, it becomes easy to obtain a film having appropriate adhesive properties.

  As a more optimal form of the (meth) acrylic resin for improving the adhesive property, the total content of normal butyl acrylate and 2-ethylhexyl acrylate in the (meth) acrylic resin is usually 30% by weight or more, It is preferably in the range of 40% by weight or more, more preferably 50% by weight or more, particularly preferably 60% by weight or more, and most preferably 70% by weight or more, and the upper limit of the preferred range is 99% by weight. Although it depends on the composition of the (meth) acrylic resin used and the composition of the pressure-sensitive adhesive layer, in particular, when it is desired to prevent the transfer of the pressure-sensitive adhesive component to the adherend with a small amount of the crosslinking agent, 2-ethylhexyl The acrylate content is usually in the range of 90% by weight or less, preferably 80% by weight or less.

  In addition, in consideration of application to in-line coating and the like, various hydrophilic functional groups can be introduced in order to obtain a water-based (meth) acrylic resin. Preferred examples of the hydrophilic functional group include a carboxylic acid group, a carboxylic acid group, a sulfonic acid group, a sulfonic acid group, and a hydroxyl group. Among them, a carboxylic acid group, a carboxylic acid group, and a hydroxyl group are preferable from the viewpoint of water resistance.

  The introduction of the carboxylic acid includes copolymerizing various carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and citraconic acid. Among the above, acrylic acid and methacrylic acid are preferred because they can be effectively dispersed in water.

  As the introduction of the hydroxyl group, various kinds of compounds such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monobutylhydrokylfumarate, and monobutylhydroxyitaconate can be used. Copolymerization of a hydroxyl group-containing monomer may be mentioned. Among them, 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are preferable in view of industrial ease of handling.

  Further, as a crosslinking reactive group, a copolymer of an amino group-containing monomer such as dimethylaminoethyl (meth) acrylate or a copolymer of an epoxy group-containing monomer such as glycidyl (meth) acrylate can be contained. is there. However, if the content is too large, it will affect the adhesive properties, so it is necessary to make it an appropriate amount.

  The proportion of the hydrophilic functional group-containing monomer in the (meth) acrylic resin is usually 30% by weight or less, preferably 1 to 20% by weight, more preferably 2 to 15% by weight, and particularly preferably 3 to 10% by weight. It is. Use in the above range facilitates aqueous development.

  The glass transition point of the (meth) acrylic resin for improving the adhesive properties is essential to be 0 ° C or lower, preferably -10 ° C or lower, more preferably -20 ° C or lower, and further preferably The range is −30 ° C. or lower, and the lower limit of the preferred range is −80 ° C. By using it in the above range, it becomes easy to obtain a film having optimal adhesive properties. When it is necessary to consider the reduction of the migration of the adhesive component to the adherend, the temperature is preferably −70 ° C. or higher, more preferably −60 ° C. or higher, and still more preferably −50 ° C. or higher.

  The urethane resin is a polymer compound having a urethane bond in a molecule, and is usually produced by a reaction between a polyol and an isocyanate. Examples of the polyol include polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, and acrylic polyols, and these compounds may be used alone or in combination.

  Polycarbonate polyols are obtained from a polyhydric alcohol and a carbonate compound by a dealcoholization reaction. Polyhydric alcohols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentane Diol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decane Diol, neopentyl glycol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane and the like. Examples of the carbonate compound include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, and ethylene carbonate. Polycarbonate polyols obtained from these reactions include, for example, poly (1,6-hexylene) carbonate and poly (3- Methyl-1,5-pentylene) carbonate and the like.

  From the viewpoint of improving the adhesive properties, the polycarbonate polyol is a polycarbonate polyol composed of a diol component having a chain alkyl chain having usually 4 to 30, preferably 4 to 20, and more preferably 6 to 12, carbon atoms. From the viewpoint of good handleability and supply stability, from among 1,6-hexanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol. Most preferably, it is a copolymerized polycarbonate polyol containing at least two selected diols.

  Examples of the polyether polyols include polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, and the like.

  From the viewpoint of improving the adhesive properties, the monomer forming the polyether is preferably an aliphatic diol having 2 to 30, preferably 3 to 20, and more preferably 4 to 12, carbon atoms, particularly a linear aliphatic diol. Is a polyether polyol.

  Polyester polyols include polycarboxylic acids (malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, etc.) or anhydrides thereof. And polyhydric alcohols (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol , 2-methyl-2-propyl-1 3-propanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol , 1,9-nonanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-hexyl-1,3-propanediol, cyclohexane Diol, bishydroxymethylcyclohexane, dimethanolbenzene, bishydroxyethoxybenzene, alkyldialkanolamine, lactone diol, etc.), and those having a derivative unit of a lactone compound such as polycaprolactone.

  In consideration of the adhesive property, among the above polyols, polycarbonate polyols and polyether polyols are more preferably used, and polycarbonate polyols are particularly preferable.

  Examples of the polyisocyanate compound used to obtain the urethane resin include aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, and tolidine diisocyanate, α, α, α ′, α ′. Aliphatic diisocyanate having an aromatic ring such as tetramethylxylylene diisocyanate, methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, aliphatic diisocyanate such as hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl Methanedi Cyanate, alicyclic diisocyanates such as isopropylidene dicyclohexyl diisocyanates. These may be used alone or in combination of two or more.

  When synthesizing the urethane resin, a chain extender may be used. The chain extender is not particularly limited as long as it has two or more active groups that react with an isocyanate group. Alternatively, a chain extender having two amino groups can be mainly used.

  Examples of the chain extender having two hydroxyl groups include aliphatic glycols such as ethylene glycol, propylene glycol and butanediol, aromatic glycols such as xylylene glycol and bishydroxyethoxybenzene, and esters such as neopentyl glycol hydroxypivalate. Glycols such as glycol can be mentioned. Examples of the chain extender having two amino groups include, for example, aromatic diamines such as tolylenediamine, xylylenediamine, diphenylmethanediamine, ethylenediamine, propylenediamine, hexanediamine, and 2,2-dimethyl-1,3- Propanediamine, 2-methyl-1,5-pentanediamine, trimethylhexanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-diamine Aliphatic diamines such as decanediamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, dicyclohexylmethanediamine, isopropylidenecyclohexyl-4,4′-diamine, 1,4-diaminocyclohexane, 3-bisaminomethylcyclohexa And alicyclic diamines such as butane.

  The urethane resin may be a solvent-based medium, but is preferably a water-based medium. In order to disperse or dissolve the urethane resin in water, there are a forced emulsification type using an emulsifier, a self-emulsification type in which a hydrophilic group is introduced into the urethane resin, and a water-soluble type. In particular, a self-emulsifying type in which an ionic group is introduced into the structure of the urethane resin to form an ionomer is preferable because of excellent storage stability of the liquid and water resistance and transparency of the obtained adhesive layer.

Examples of the ionic group to be introduced include various groups such as a carboxyl group, sulfonic acid, phosphoric acid, phosphonic acid, and quaternary ammonium salt, and a carboxyl group is preferable. As a method for introducing a carboxyl group into the urethane resin, various methods can be employed in each stage of the polymerization reaction. For example, there is a method in which a resin having a carboxyl group is used as a copolymerization component during the synthesis of a prepolymer, or a method in which a component having a carboxyl group is used as one component such as a polyol, a polyisocyanate, or a chain extender. In particular, a method in which a desired amount of a carboxyl group is introduced by using a carboxyl group-containing diol depending on the charged amount of this component is preferable.

For example, copolymerizing dimethylolpropionic acid, dimethylolbutanoic acid, bis- (2-hydroxyethyl) propionic acid, bis- (2-hydroxyethyl) butanoic acid, etc. with a diol used for the polymerization of urethane resin. Can be. The carboxyl group is preferably in the form of a salt neutralized with ammonia, an amine, an alkali metal, an inorganic alkali or the like. Particularly preferred are ammonia, trimethylamine and triethylamine.
In such a urethane resin, a carboxyl group from which a neutralizing agent has been removed in a drying step after coating can be used as a crosslinking reaction point by another crosslinking agent. As a result, the stability of the liquid before coating is excellent, and the durability, solvent resistance, water resistance, blocking resistance, and the like of the obtained adhesive layer can be further improved.

  The glass transition point of the urethane resin for improving the adhesive property is essential to be 0 ° C. or lower, preferably -10 ° C. or lower, more preferably −20 ° C. or lower, and still more preferably −30 ° C. The range is as follows, and the lower limit of the preferred range is −80 ° C. By using it in the above range, it becomes easy to obtain a film having optimal adhesive properties.

  The above-mentioned resin having a glass transition point of 0 ° C. or lower may be used alone or in combination of two or more. Preferable embodiments when two or more kinds are used in combination include a polyester resin and a urethane resin, a polyester resin and an acrylic resin, and a urethane resin and an acrylic resin.

  It is also preferable to use a crosslinking agent together from the viewpoint of the strength of the adhesive layer. Although an investigation has been made mainly on an adhesive layer using a resin having a glass transition point of 0 ° C. or lower, it has been found in the investigation that the adhesive component migrates to the adherend under severe conditions. Therefore, as a result of various studies, it was found that the use of a crosslinking agent can improve the transfer of the adhesive layer to the adherend.

  As the crosslinking agent, conventionally known materials can be used, and examples thereof include a melamine compound, an isocyanate compound, an epoxy compound, an oxazoline compound, a carbodiimide compound, a silane coupling compound, a hydrazide compound, and an aziridine compound. Among them, melamine compounds, isocyanate-based compounds, epoxy compounds, oxazoline compounds, carbodiimide-based compounds, and silane coupling compounds are preferable.Furthermore, melamine compounds and isocyanate-based compounds can be appropriately maintained in adhesive strength and easily adjusted. Compounds and epoxy compounds are more preferred, and isocyanate-based compounds and epoxy compounds are particularly preferred because the combined use can suppress a decrease in adhesive strength. Further, from the viewpoint that transfer to an adherend can be reduced, a melamine compound or an isocyanate compound is preferable, and among them, a melamine compound is particularly preferable. Further, a melamine compound is particularly preferable from the viewpoint of the strength of the adhesive layer. These crosslinking agents may be used alone or in combination of two or more.

  In addition, depending on the configuration of the adhesive layer and the type of the crosslinking agent, if the content of the crosslinking agent in the adhesive layer is too large, the adhesive properties may be too low. Therefore, it is preferable to pay attention to the content in the adhesive layer.

  The melamine compound is a compound having a melamine skeleton in the compound, for example, an alkylolated melamine derivative, a compound partially or completely etherified by reacting an alcohol with an alkylolated melamine derivative, and Mixtures can be used. As the alcohol used for the etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like are preferably used. The melamine compound may be any of a monomer, a dimer or a multimer, or a mixture thereof. Considering the reactivity with various compounds, the melamine compound preferably contains a hydroxyl group. Further, melamine co-condensed with a part of melamine can be used, and a catalyst can be used to increase the reactivity of the melamine compound.

  The isocyanate-based compound is a compound having an isocyanate derivative structure represented by isocyanate or blocked isocyanate. Examples of the isocyanate include aromatic isocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate, and aromatic rings such as α, α, α ′, α′-tetramethyl xylylene diisocyanate. Aliphatic isocyanates such as aliphatic isocyanate, methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), isopropylidene dicyclohexyl diisocyanate Ne Alicyclic isocyanates such as bets are exemplified. Further, polymers and derivatives such as buret compounds, isocyanurate compounds, uretdione compounds, and carbodiimide modified products of these isocyanates are also included. These may be used alone or in combination of two or more. Among the above isocyanates, aliphatic isocyanates or alicyclic isocyanates are more preferable than aromatic isocyanates in order to avoid yellowing due to ultraviolet rays.

  When used in the form of a blocked isocyanate, examples of the blocking agent include bisulfites, phenolic compounds such as phenol, cresol and ethylphenol, propylene glycol monomethyl ether, ethylene glycol, benzyl alcohol, alcohols such as methanol and ethanol. Compounds, active methylene compounds such as dimethyl malonate, diethyl malonate, methyl isobutanoyl acetate, methyl acetoacetate, ethyl acetoacetate, acetylacetone, mercaptan compounds such as butyl mercaptan, dodecyl mercaptan, ε-caprolactam, δ-valerolactam, etc. Lactam compounds, amine compounds such as diphenylaniline, aniline, ethyleneimine, acetanilide, acid amide compounds of acetic acid amide, Oxime compounds such as aldehyde, acetoaldoxime, acetone oxime, methyl ethyl ketone oxime, and cyclohexanone oxime may be mentioned, and these may be used alone or in combination of two or more. Among these, an isocyanate compound blocked by an active methylene compound is particularly preferable from the viewpoint of being particularly effective in reducing the transferability of the adhesive layer to an adherend.

  Further, the isocyanate-based compound may be used alone, or may be used as a mixture or a binder with various polymers. From the viewpoint of improving the dispersibility and crosslinkability of the isocyanate compound, it is preferable to use a mixture or a binder with a polyester resin or a urethane resin.

  The epoxy compound is a compound having an epoxy group in the molecule, for example, a condensate of epichlorohydrin with a hydroxyl group or an amino group such as ethylene glycol, polyethylene glycol, glycerin, polyglycerin, and bisphenol A, There are polyepoxy compounds, diepoxy compounds, monoepoxy compounds, glycidylamine compounds and the like. Examples of the polyepoxy compound include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, and trimethylolpropane. Examples of the polyglycidyl ether and diepoxy compound include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and propylene glycol diglycidyl ether. , Polypropylene glycol diglycidyl ether, Examples of tetramethylene glycol diglycidyl ether and monoepoxy compounds include, for example, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and glycidylamine compounds of N, N, N ′, N′-tetraglycidyl-m-xylyl. And diamine, 1,3-bis (N, N-diglycidylamino) cyclohexane and the like.

  Among these, a polyether-based epoxy compound is preferable from the viewpoint of good adhesive properties. The amount of the epoxy group is preferably a polyfunctional polyepoxy compound having three or more functional groups rather than two functional groups.

  The oxazoline compound is a compound having an oxazoline group in the molecule, and is particularly preferably a polymer containing an oxazoline group, and can be prepared by polymerization of an addition-polymerizable oxazoline group-containing monomer alone or with another monomer. The addition-polymerizable oxazoline group-containing monomer is 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, Examples thereof include 2-isopropenyl-4-methyl-2-oxazoline and 2-isopropenyl-5-ethyl-2-oxazoline. One or a mixture of two or more of these can be used. Among these, 2-isopropenyl-2-oxazoline is easily available industrially and is preferable. The other monomer is not limited as long as it is a monomer copolymerizable with an addition-polymerizable oxazoline group-containing monomer, and examples thereof include an alkyl (meth) acrylate (as the alkyl group, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, (meth) acrylic esters such as n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group and cyclohexyl group); acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and styrene Unsaturated carboxylic acids such as sulfonic acid and salts thereof (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); unsaturated nitriles such as acrylonitrile, methacrylonitrile; (meth) acrylamide, N-alkyl ( (Meth) acrylamide, N, N-dialkyl (meth) acrylamide, Examples of the alkyl group include unsaturated amides such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, etc .; vinyl acetate And vinyl esters such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; and halogen-containing α, β-unsaturated monomers such as vinyl chloride, vinylidene chloride and vinyl fluoride. And the like; α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene; and the like, and one or more of these monomers can be used.

  The oxazoline group content of the oxazoline compound is usually in the range of 0.5 to 10 mmol / g, preferably 1 to 9 mmol / g, more preferably 3 to 8 mmol / g, and particularly preferably 4 to 6 mmol / g. By using in the above range, the durability is improved, and the adjustment of the adhesive property becomes easy.

  A carbodiimide compound is a compound having one or more carbodiimide or carbodiimide derivative structures in a molecule. For better adhesive layer strength and the like, a polycarbodiimide compound having two or more in the molecule is more preferable.

  The carbodiimide compound can be synthesized by a conventionally known technique, and generally, a condensation reaction of a diisocyanate compound is used. The diisocyanate compound is not particularly limited and may be any of an aromatic type and an aliphatic type. Specifically, tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, hexa Examples include methylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl diisocyanate, and dicyclohexylmethane diisocyanate.

  Further, within a range not to lose the effects of the present invention, in order to improve the water solubility and water dispersibility of the polycarbodiimide compound, a surfactant may be added, and a polyalkylene oxide, a quaternary ammonium salt of dialkylamino alcohol. And a hydrophilic monomer such as a hydroxyalkyl sulfonate.

  The content of the carbodiimide group contained in the carbodiimide-based compound is usually 100 to 1000, preferably 250 to 800, more preferably 300 to carbodiimide equivalent (weight [g] of the carbodiimide compound for giving 1 mol of carbodiimide group). To 700, more preferably 350 to 650. Use in the above range is preferable because the strength of the adhesive layer is improved.

  A silane coupling compound is an organosilicon compound having an organic functional group and a hydrolyzable group such as an alkoxy group in one molecule. For example, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4- Epoxy-containing compounds such as epoxycyclohexyl) ethyltrimethoxysilane, vinyl-containing compounds such as vinyltrimethoxysilane and vinyltriethoxysilane, styryl-containing compounds such as p-styryltrimethoxysilane and p-styryltriethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropylmethyldiethoxysilane, etc. (Meth) acrylic group-containing compound, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl)- 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldiethoxysilane, 3-triethoxysilyl-N Amino-containing compounds such as-(1,3-dimethylbutylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, tris (trimethoxysilylpropyl) Isocyanurate, tris (triethoxysilylpropyl) i Isocyanurate group-containing compounds such as cyanurate; and mercapto group-containing compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropylmethyldiethoxysilane. Can be

  Among the above compounds, epoxy group-containing silane coupling compounds, double bond-containing silane coupling compounds such as vinyl group and (meth) acrylic group, and amino group-containing silane coupling from the viewpoint of maintaining the strength of the adhesive layer and the adhesive strength. Compounds are more preferred.

  These cross-linking agents are used in a design for improving the performance of the pressure-sensitive adhesive layer by reacting in a drying process or a film forming process. It is presumed that an unreacted product of these crosslinking agents, a compound after the reaction, or a mixture thereof (a compound derived from the crosslinking agent) is present in the completed adhesive layer.

  Further, from the viewpoints of the appearance of the adhesive layer, the adjustment of the adhesive strength, the strengthening of the adhesive layer, the adhesion to the base film, the blocking resistance, and the prevention of the transfer of the adhesive component to the adherend, the glass transition point is 0 ° C. It is also possible to use more than one resin in combination. As the resin having a glass transition point exceeding 0 ° C., conventionally known materials can be used. Among them, polyester resin, acrylic resin, urethane resin and polyvinyl (polyvinyl alcohol, vinyl chloride-vinyl acetate copolymer, etc.) are preferable. In consideration of the influence on the appearance and the adhesive strength of the adhesive layer, polyester resin, acrylic resin and urethane are preferable. Resins selected from resins are preferred. However, depending on the method of use, there is a concern that the adhesive strength may be significantly reduced, and caution is required.

  The resin having a glass transition point higher than 0 ° C. is used for the appearance of the adhesive layer, the adjustment of the adhesive strength, the strengthening of the adhesive layer, the adhesion to the substrate film, the improvement of the blocking resistance, and the like. Care must be taken because there is a concern that the adhesive strength may be significantly reduced.

  As the polyester resin having a glass transition point exceeding 0 ° C., a polyester resin containing an aromatic compound is preferable. Further, as the aromatic compound, an aromatic polycarboxylic acid is more preferable than an aromatic polyhydroxy compound from the viewpoint of adjustment of adhesive strength and the like. The content of the aromatic polycarboxylic acid in the acid component in the polyester resin is usually at least 50% by weight, preferably at least 70% by weight, more preferably at least 80% by weight, particularly preferably at least 90% by weight. %, And preferably does not contain an aliphatic polycarboxylic acid, particularly an aliphatic polycarboxylic acid having 6 or more carbon atoms, from the viewpoint of adjustment of adhesive strength and blocking resistance.

  As the urethane resin as a resin having a glass transition point exceeding 0 ° C., various urethanes can be used. Among them, urethanes based on polyester polyols are preferable from the viewpoint of adjustment of adhesive strength, slipperiness, and blocking resistance. Resins are more preferred. Further, the polyester polyols preferably contain an aromatic compound, and an aromatic polycarboxylic acid is more preferable than an aromatic polyhydroxy compound from the viewpoint of adjustment of adhesive strength and the like. The content of the aromatic polycarboxylic acid in the urethane resin is generally in the range of 5 to 80% by weight, preferably 15 to 65% by weight, and more preferably 20 to 50% by weight. By using in this range, it becomes easy to adjust the adhesive strength and to improve the performance of blocking resistance.

  The glass transition point of the resin having a glass transition point higher than 0 ° C. is usually 10 ° C. or higher, preferably 20 ° C. or higher, more preferably 30 ° C. or higher, and the upper limit of the preferable range is 150 ° C. When the content is in the above range, the adhesive strength can be adjusted without excessively decreasing, and the performance such as the slip property and the blocking resistance can be easily improved.

  Further, in the formation of the adhesive layer, particles can be used in combination for the purpose of improving blocking, slipperiness, and adjusting the adhesive property. However, care must be taken because the adhesive strength may decrease depending on the type of particles used. In order not to significantly reduce the adhesive strength, it is preferable that the average particle size of the particles used is 3 times or less the thickness of the adhesive layer, more preferably 1.5 times or less, further preferably 1.0 times or less. It is particularly preferably in the range of 0.8 times or less. In particular, when it is desired to exhibit the adhesive performance of the resin of the adhesive layer as it is, it may be preferable that the adhesive layer does not contain particles.

  The functional layer provided on the polyester film surface on the side opposite to the adhesive layer is provided for reducing the reflectance from the film surface, and specifically, the minimum value of the absolute reflectance in the wavelength range of 400 to 800 nm. Is less than 4.0% as an essential requirement. The purpose of reducing the reflectance is to increase the transmittance when the laminated polyester film and the laminated polyester film are bonded to an adherend. By increasing the transmittance, visibility is improved, and, for example, inspection of foreign substances by a machine can be performed more easily.

  In the case of a laminated polyester film alone, improving the transmittance by the adhesive layer is also meaningful.However, in order to improve the transmittance in a state where the adhesive layer of the laminated polyester film is bonded to the adherend, the layer on the side to be bonded is required. Since the contribution to the transmittance is not large, it is important to improve the transmittance by designing the non-bonded side, that is, the side opposite to the film from the adhesive layer. Therefore, the goal is to reduce the reflectance, which is opposite to the transmittance. In particular, it is effective to provide a functional layer for reducing the reflectance on the side opposite to the film from the adhesive layer.

  In order to improve the transmittance, it is essential for the reflectance on the functional layer side that the minimum value of the absolute reflectance in a wavelength range of 400 to 800 nm is less than 4.0%. Further, as a preferred mode, when the horizontal axis represents the wavelength and the vertical axis represents the absolute reflectance, the absolute reflectance has one local minimum value in the wavelength range of 400 to 800 nm, and the local minimum value (the local minimum value is (The minimum value because it is one) is less than 4.0%. A more preferable range of the minimum (minimum) wavelength is 400 to 750 nm, further preferably 450 to 700 nm, and particularly preferably 500 to 650 nm. The preferred range of the absolute reflectance at the minimum value (minimum value) is 3.5% or less, more preferably 3.0% or less, and further preferably 2.5% or less. The lower limit of the preferred range is 0.1%. With the above range, the transmittance can be effectively improved.

  As the compound forming the functional layer, a compound having a low refractive index is preferable. For example, acrylic resin or urethane resin is generally preferable because of its low refractive index, and acrylic resin is more preferable. Various resins used for the above-mentioned adhesive layer can be used regardless of the glass transition point. Further, in order to further lower the refractive index, it is also a preferable embodiment to use a compound in which a fluorine atom is incorporated in a resin.

  In order to further increase the strength of the functional layer, it is preferable to use a crosslinking agent together. As the cross-linking agent, the same cross-linking agent as that used in the adhesive layer can be used. Among them, melamine compounds, oxazoline compounds, epoxy compounds, isocyanate compounds, carbodiimide compounds, and silane coupling compounds are preferable in terms of particularly high strength and ease of use, and melamine in terms of higher strength. Compounds and oxazoline compounds are preferred. However, since the melamine compound has an aromatic structure and has a higher refractive index than other crosslinking agents, it is preferable not to use too much.

  These cross-linking agents are used in a design for improving the performance of the functional layer by reacting in a drying process or a film forming process. It is presumed that an unreacted product of these crosslinking agents, a compound after the reaction, or a mixture thereof (compound derived from the crosslinking agent) exists in the completed functional layer.

  In addition, when the laminated polyester film is held in an overlapping state, blocking may be concerned depending on the adhesive strength of the adhesive layer. In order to improve the blocking, the functional layer may contain various release agents. Further, the functional layer may contain particles. Further, an antistatic agent can be added to prevent electrification due to peeling or friction.

  The release agent that can be contained in the functional layer is not particularly limited, and a conventionally known release agent can be used.Examples include a long-chain alkyl group-containing compound, a fluorine compound, a silicone compound, and a wax. No. Among these, low contamination is preferred, and a long-chain alkyl compound or a fluorine compound is preferable from the viewpoint of excellent blocking reduction.If the halogen content is not preferable, a long-chain alkyl compound is preferable. Silicone compounds are preferred. In addition, wax is effective for improving the surface contamination removal properties. These release agents may be used alone or in combination of two or more.

  The long-chain alkyl group-containing compound is a compound having a linear or branched alkyl group having usually 6 or more, preferably 8 or more, more preferably 12 or more carbon atoms. Examples of the alkyl group include a hexyl group, an octyl group, a decyl group, a lauryl group, an octadecyl group, a behenyl group, and the like. Examples of the compound having an alkyl group include various long-chain alkyl group-containing polymer compounds, long-chain alkyl group-containing amine compounds, long-chain alkyl group-containing ether compounds, and long-chain alkyl group-containing quaternary ammonium salts. . In consideration of heat resistance and contamination, a polymer compound is preferable. From the viewpoint that a releasability can be obtained effectively, a polymer compound having a long-chain alkyl group in the side chain is more preferable.

The polymer compound having a long-chain alkyl group in the side chain can be obtained by reacting a polymer having a reactive group with a compound having an alkyl group capable of reacting with the reactive group. Examples of the reactive group include a hydroxyl group, an amino group, a carboxyl group, and an acid anhydride.
Examples of the compound having a reactive group include polyvinyl alcohol, polyethylene imine, polyethylene amine, a reactive group-containing polyester resin, and a reactive group-containing poly (meth) acryl resin. Among these, polyvinyl alcohol is preferred in consideration of mold release properties and ease of handling.

  The compound having an alkyl group capable of reacting with the above reactive group includes, for example, hexyl isocyanate, octyl isocyanate, decyl isocyanate, lauryl isocyanate, octadecyl isocyanate, isocyanate containing a long-chain alkyl group such as behenyl isocyanate, hexyl chloride, octyl chloride , Decyl chloride, lauryl chloride, octadecyl chloride, behenyl chloride, and the like, a long-chain alkyl group-containing acid chloride, a long-chain alkyl group-containing amine, and a long-chain alkyl group-containing alcohol. Among these, a long-chain alkyl group-containing isocyanate is preferable, and octadecyl isocyanate is particularly preferable in consideration of mold release properties and ease of handling.

  Further, the polymer compound having a long-chain alkyl group in the side chain can be obtained by polymerizing a long-chain alkyl (meth) acrylate or copolymerizing a long-chain alkyl (meth) acrylate with another vinyl group-containing monomer. . Examples of the long-chain alkyl (meth) acrylate include hexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, octadecyl (meth) acrylate, and behenyl (meth) acrylate. Can be

  The fluorine compound is a compound containing a fluorine atom in the compound. Organic fluorine compounds are preferably used in view of application appearance by in-line coating, and examples thereof include perfluoroalkyl group-containing compounds, polymers of fluorine-containing olefin compounds, and aromatic fluorine compounds such as fluorobenzene. . From the viewpoint of releasability, a compound having a perfluoroalkyl group is preferable. Further, as the fluorine compound, a compound containing a long-chain alkyl compound as described later can also be used.

  The compound having a perfluoroalkyl group is, for example, perfluoroalkyl (meth) acrylate, perfluoroalkylmethyl (meth) acrylate, 2-perfluoroalkylethyl (meth) acrylate, 3-perfluoroalkylpropyl (meth) acrylate , A perfluoroalkyl group-containing (meth) acrylate such as 3-perfluoroalkyl-1-methylpropyl (meth) acrylate, 3-perfluoroalkyl-2-propenyl (meth) acrylate, a polymer thereof, and a perfluoroalkylmethyl vinyl ether , 2-perfluoroalkyl ethyl vinyl ether, 3-perfluoropropyl vinyl ether, 3-perfluoroalkyl-1-methylpropyl vinyl ether, 3-perfluoroalkyl-2-propenylbi Perfluoroalkyl group-containing vinyl ether and polymers thereof such as ether, and the like. A polymer is preferable in consideration of heat resistance and contamination. The polymer may be a single compound or a polymer of a plurality of compounds. Further, from the viewpoint of releasability, the perfluoroalkyl group preferably has 3 to 11 carbon atoms. Further, it may be a polymer with a compound containing a long-chain alkyl compound as described later. Further, from the viewpoint of adhesion to the base material, a polymer with vinyl chloride is also preferable.

  The silicone compound is a compound having a silicone structure in the molecule, and examples thereof include alkyl silicones such as dimethyl silicone and diethyl silicone, phenyl silicone having a phenyl group, and methylphenyl silicone. Silicones having various functional groups can also be used, for example, ether groups, hydroxyl groups, amino groups, epoxy groups, carboxylic acid groups, halogen groups such as fluorine, perfluoroalkyl groups, various alkyl groups and various types. And hydrocarbon groups such as aromatic groups. As other functional groups, silicones having a vinyl group and hydrogen silicones in which hydrogen atoms are directly bonded to silicon atoms are also common, and both are used together to form an addition-type (type by addition reaction of vinyl group and hydrogen silane) silicone. It is also possible to use as.

  Further, as the silicone compound, it is also possible to use a modified silicone such as acryl-grafted silicone, silicone-grafted acryl, amino-modified silicone and perfluoroalkyl-modified silicone. In consideration of heat resistance and contamination, it is preferable to use a curable silicone resin. As a type of the curable silicone resin, any of a curing reaction type such as a condensation type, an addition type, and an active energy ray curable type can be used. Among these, a condensation type silicone compound is preferable from the viewpoint that transfer of the back surface when formed into a roll is small.

  As a preferable mode when a silicone compound is used, a polyether group-containing silicone compound is preferable from the viewpoint that the back surface transfer is small, the dispersibility in an aqueous solvent is high, and the suitability for in-line coating is high. The polyether group may be present on the side chain or terminal of the silicone, or may be present on the main chain. From the viewpoint of dispersibility in an aqueous solvent, it is preferable to have the compound at a side chain or at a terminal.

  As the polyether group, a conventionally known structure can be used. From the viewpoint of dispersibility of the aqueous solvent, an aliphatic polyether group is preferable to an aromatic polyether group, and among the aliphatic polyether groups, an alkyl polyether group is preferable. Further, from the viewpoint of synthesis due to steric hindrance, a linear alkyl polyether group is preferable to a branched alkyl polyether group, and among them, a polyether group composed of a linear alkyl having 8 or less carbon atoms is preferable. Further, when the developing solvent is water, a polyethylene glycol group or a polypropylene glycol group is preferable in consideration of dispersibility in water, and a polyethylene glycol group is particularly preferable.

  The number of ether bonds in the polyether group is usually in the range of 1 to 30, preferably 2 to 20, and more preferably 3 to 3 from the viewpoint of improving dispersibility in an aqueous solvent and durability of the functional layer. There are 15 ranges. When the number of ether bonds is small, the dispersibility is deteriorated. On the other hand, when the number is too large, durability and release performance are deteriorated.

  When having a polyether group on the side chain or terminal of the silicone, the terminal of the polyether group is not particularly limited, and may be a hydroxyl group, an amino group, a thiol group, a hydrocarbon group such as an alkyl group or a phenyl group, a carboxylic acid group, Various functional groups such as a sulfonic acid group, an aldehyde group and an acetal group can be used. Among them, a hydroxyl group, an amino group, a carboxylic acid group, and a sulfonic acid group are preferred in consideration of the dispersibility in water and the crosslinkability for improving the strength of the functional layer, and the hydroxyl group is particularly optimal.

  The content of the polyether group in the polyether group-containing silicone is usually in the range of 0.001 to 0.30%, preferably 0.01 to 0.20%, in terms of the molar ratio of the siloxane bond of the silicone to 1. , More preferably in the range of 0.03 to 0.15%, particularly preferably in the range of 0.05 to 0.12%. When used within this range, the dispersibility in water, the durability of the functional layer, and good releasability can be maintained.

  The molecular weight of the polyether group-containing silicone is preferably not too large in consideration of dispersibility in an aqueous solvent, and is preferably large in consideration of the durability and release performance of the functional layer. It is required to balance these two properties, and the number average molecular weight is usually in the range of 1,000 to 100,000, preferably in the range of 3,000 to 30,000, and more preferably in the range of 5,000 to 10,000.

  In consideration of the aging of the functional layer, the release performance, and the contamination of various processes, it is preferable that the low molecular weight component (number average molecular weight of 500 or less) of silicone is as small as possible. The total ratio is usually 15% by weight or less, preferably 10% by weight or less, more preferably 5% by weight or less. When a condensation type silicone is used, a vinyl group (vinyl silane) and a hydrogen group (hydrogen silane) bonded to silicon remain in the functional layer unreacted, and cause various changes in performance over time. The content of the functional group therein is preferably 0.1 mol% or less, and more preferably not contained.

  Since it is difficult to apply the polyether group-containing silicone alone, it is preferable to use the silicone dispersed in water. Various known dispersants can be used for dispersion, and examples thereof include an anionic dispersant, a nonionic dispersant, a cationic dispersant, and an amphoteric dispersant. Among these, in consideration of the dispersibility of the polyether group-containing silicone and the compatibility with a polymer other than the polyether group-containing silicone that can be used for forming the functional layer, an anionic dispersant and a nonionic dispersant are preferable. . In addition, a fluorine compound can be used for these dispersants.

  Examples of the anionic dispersant include sodium dodecylbenzene sulfonate, sodium alkyl sulfonate, sodium alkylnaphthalene sulfonate, sodium dialkyl sulfosuccinate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl allyl ether sulfate, and polyoxyalkylene alkenyl. Sulfonates and sulfates such as ammonium ether sulfate, carboxylate such as sodium laurate and potassium oleate, alkyl phosphate, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl phenyl ether phosphate Phosphate systems such as salts may be mentioned. Among these, a sulfonate salt is preferred from the viewpoint of good dispersibility.

  Examples of the nonionic dispersant include, for example, an ether type obtained by adding an alkylene oxide such as ethylene oxide or propylene oxide to a compound having a hydroxyl group such as a higher alcohol or an alkylphenol, and a polyhydric alcohol such as glycerin or a saccharide being ester-bonded to a fatty acid. Examples include an ester type, an ester ether type in which an alkylene oxide is added to a fatty acid or polyhydric alcohol fatty acid ester, and an amide type in which a hydrophobic group and a hydrophilic group are via an amide bond. Among them, ether type is preferable in consideration of solubility and stability in water, and type in which ethylene oxide is added is more preferable in consideration of handleability.

  Since it depends on the molecular weight and structure of the polyether group-containing silicone used and also on the type of dispersant used, it cannot be unconditionally determined. The weight ratio is usually in the range of 0.01 to 0.5, preferably 0.05 to 0.4, and more preferably 0.1 to 0.3.

  The wax is a wax selected from natural waxes, synthetic waxes, and waxes containing these waxes. Natural waxes are vegetable waxes, animal waxes, mineral waxes, and petroleum waxes. Examples of the vegetable wax include candelilla wax, carnauba wax, rice wax, wood wax, jojoba oil and the like. Animal waxes include beeswax, lanolin, and whale wax. Examples of the mineral wax include montan wax, ozokerite, and ceresin. Examples of the petroleum wax include paraffin wax, microcrystalline wax, petrolatum and the like. Examples of the synthetic wax include a synthetic hydrocarbon, a modified wax, a hydrogenated wax, a fatty acid, an acid amide, an amine, an imide, an ester, and a ketone. Examples of the synthetic hydrocarbons include Fischer-Tropsch wax (also known as Sasol wax) and polyethylene wax, and in addition, low molecular weight polymers (specifically, polymers having a number average molecular weight of 500 to 20,000). The following polymers also include, for example, polypropylene, ethylene / acrylic acid copolymer, polyethylene glycol, polypropylene glycol, and a block or graft conjugate of polyethylene glycol and polypropylene glycol. Examples of the modified wax include montan wax derivatives, paraffin wax derivatives, and microcrystalline wax derivatives. The derivative herein is a compound obtained by any of purification, oxidation, esterification, saponification, or a combination thereof. Hydrogenated waxes include hardened castor oil, and hardened castor oil derivatives.

  Among these, from the viewpoint of stabilizing the characteristics, synthetic waxes are preferable, and among them, polyethylene wax is more preferable, and oxidized polyethylene wax is more preferable. The number average molecular weight of the synthetic wax is generally in the range of 500 to 30,000, preferably 1,000 to 15,000, more preferably 2,000 to 8,000, from the viewpoint of stability of properties such as blocking and handling.

As the particles that can be contained in the functional layer, the larger the average particle diameter of the particles and the larger the content, the greater the effects of reducing blocking and improving the slipperiness. However, if the average particle size is too large or if the content is too large, the haze increases, so care must be taken in applications where haze is not required to be high.

  The average particle size of the particles used in the functional layer for improving blocking is usually 10 to 2000 nm, preferably 50 to 1000 nm, more preferably 100 to 700 nm, and particularly preferably 200 to 500 nm. If the average particle size is too large, the particles may fall off. Conversely, if the average particle size is too small, the blocking cannot be reduced, and the slipperiness may not be sufficient. By using in the above range, blocking with the adhesive layer can be reduced, and further, a film having improved slipperiness and easy to handle can be obtained.

  Further, as the above-mentioned particles, various types of conventionally known particles can be used, for example, silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, zirconium oxide, Examples include inorganic particles such as titanium oxide, and organic particles such as an acrylic resin, a styrene resin, a urea resin, a phenol resin, an epoxy resin, and a benzoguanamine resin. Among them, inorganic particles are preferred in that they can impart hardness, and when formed by coating, silica particles are more preferred in consideration of stability in the state of a coating solution.

  The functional layer may be provided by coating, may be provided by in-line coating, or may employ off-line coating. In-line coating is preferably used from the viewpoint of stabilization of various performances of the functional layer due to production cost and in-line heat treatment.

  Further, within a range that does not impair the gist of the present invention, an antifoaming agent, a coating improver, a thickener, an organic lubricant, an antistatic agent, an ultraviolet absorber, if necessary for forming the adhesive layer and the functional layer, It is also possible to use an antioxidant, a foaming agent, a dye, a pigment and the like in combination.

As a ratio in the pressure-sensitive adhesive layer constituting the laminated polyester film, a resin having a glass transition point of 0 ° C. or lower is usually 5% by weight or more, preferably 10 to 99.5% by weight, more preferably 30 to 98% by weight, More preferably, it is in the range of 45 to 96% by weight, particularly preferably 55 to 94% by weight, and most preferably 70 to 90% by weight. By using in the above range, a sufficient adhesive strength can be easily obtained and the adhesive strength can be easily adjusted. If the content is too small, the adhesive strength may be reduced, so that it may be necessary to take measures such as increasing the thickness of the adhesive layer.
However, care must be taken in order to increase the film thickness, as this may adversely affect productivity, such as lowering the line speed depending on the degree or the case.

  As a proportion in the adhesive layer constituting the laminated polyester film, the crosslinking agent is usually 0.5 to 80% by weight, preferably 1 to 65% by weight, more preferably 3 to 50% by weight, and particularly preferably 5 to 40% by weight. %, Most preferably from 8 to 25% by weight. When used in the above range, the strength of the pressure-sensitive adhesive layer can be improved, the transfer of the pressure-sensitive adhesive layer to the adherend can be reduced, and the adhesion can be easily adjusted. If the content is too small, the transfer to the adherend will increase.On the other hand, if the content is too large, the adhesive strength may decrease, so some measures such as increasing the thickness of the adhesive layer are necessary. May be. However, in order to increase the film thickness, it is necessary to pay attention to the degree and the case where the line speed is reduced, which may adversely affect the productivity.

  As a proportion in the adhesive layer constituting the laminated polyester film, the particles are usually 70% by weight or less, preferably 0.1 to 50% by weight, more preferably 0.5 to 30% by weight, and particularly preferably 1 to 20% by weight. % Range. When used in the above range, sufficient adhesive properties, anti-blocking properties and slipperiness are easily obtained.

  The resin having a glass transition point exceeding 0 ° C. as a proportion in the adhesive layer constituting the laminated polyester film is usually in a range of 80% by weight or less, preferably 50% by weight or less, more preferably 30% by weight or less. When used in the above range, good appearance of the pressure-sensitive adhesive layer, adjustment of the adhesive strength, reinforcement of the pressure-sensitive adhesive layer, adhesion to the substrate film, and improvement in anti-blocking property can be expected. If the content is too large, the adhesive strength is reduced, so that it may be necessary to take measures such as increasing the thickness of the adhesive layer.

  As a ratio in the functional layer constituting the laminated polyester film, the content of the acrylic resin or the urethane resin is usually at least 30% by weight, preferably at least 55% by weight, more preferably at least 70% by weight, particularly preferably at least 85% by weight. The above range is 100% by weight (that is, all components of the functional layer are acrylic resin or urethane resin), but the upper limit of the preferable range is 99% by weight. When used in the above range, the refractive index of the functional layer is reduced, and the reflectance is reduced, so that the transmittance can be improved.

  As a ratio in the functional layer constituting the laminated polyester film, the content of the crosslinking agent is usually 60% by weight or less, preferably 40% by weight or less, more preferably 25% by weight or less, and particularly preferably 10% by weight or less. And may be 0% by weight, but the lower limit of the preferred range is 1% by weight. By using in the above range, the strength of the functional layer can be increased.

  When a melamine compound is selected as the cross-linking agent, the melamine compound is usually 40% by weight or less, preferably 25% by weight or less, more preferably 10% by weight or less, and particularly preferably 8% by weight, as a ratio in the functional layer. The range is as follows. By using in the above range, the strength can be increased while keeping the reflectance of the functional layer low.

  As a proportion in the functional layer constituting the laminated polyester film, the content of the particles is usually 30% by weight or less, preferably 1 to 20% by weight, more preferably 2 to 10% by weight. By using in the above range, blocking resistance and slipperiness can be improved while maintaining the transparency of the functional layer.

  The components in the adhesive layer and the functional layer can be analyzed by, for example, TOF-SIMS, ESCA, fluorescent X-ray, IR, and the like.

  Regarding the formation of the adhesive layer and the functional layer, the above series of compounds are used as a solution or a dispersion of a solvent, and the solid content concentration is adjusted to approximately 0.1 to 80% by weight. It is preferred to produce a laminated polyester film. In particular, when provided by in-line coating, an aqueous solution or an aqueous dispersion is more preferable. For the purpose of improving dispersibility in water, improving film forming properties, and the like, the coating solution may contain a small amount of an organic solvent. Further, only one kind of the organic solvent may be used, or two or more kinds may be used as appropriate.

  The thickness of the adhesive layer is essential to be 10 μm or less, preferably 1 nm to 5 μm, more preferably 5 to 2500 nm, further preferably 10 to 1000 nm, particularly preferably 20 to 700 nm, and most preferably 30 to 400 nm. Range. When the thickness of the adhesive layer is in the above range, it becomes easy to maintain appropriate adhesive properties and blocking properties.

  A general adhesive layer has a thick film thickness exceeding 10 μm. In such a case, for example, when the adhesive film is used for manufacturing a polarizing plate, the adhesive film is coated with a polarizing plate, a retardation plate, a viewing angle enlarging plate, or the like. At the time of cutting by laminating with a body, the adhesive in the adhesive layer may protrude significantly. However, the protrusion can be minimized by adjusting the film thickness in the above-mentioned range. This effect is better as the thickness of the adhesive layer is smaller. Further, as the thickness of the adhesive layer is smaller, the absolute amount of the adhesive layer present on the film may be smaller, so that the components of the adhesive layer are transferred to the adherend and the adhesive residue is effectively reduced. Furthermore, it was also found that by setting the film thickness in the above range, it is possible to achieve a moderate adhesive strength that is not too strong.For example, for the polarizing plate manufacturing process, both the adhesive performance and the peeling performance of peeling after bonding are compatible. When it is used for an application that needs to be performed, the operation of laminating and peeling can be easily performed, and an optimal film can be obtained. The thinner the film thickness, the more effective the blocking property. When an adhesive layer is formed by in-line coating, it is easy to manufacture and is preferable. Conversely, when the film thickness is too small, the adhesive property depends on the configuration of the adhesive layer. Since it may disappear, it is preferable to use it in the above-mentioned suitable range according to the application.

  The thickness of the functional layer depends on the refractive index of the functional layer and is not unconditional, but is usually 1 nm to 3 μm, preferably 10 nm to 1 μm, more preferably 30 to 500 nm, particularly preferably 50 to 200 nm. Preferably it is in the range of 70 to 150 nm. By using the thickness of the functional layer in the above range, the reflectance becomes low.

  As a method for forming the adhesive layer or the functional layer, for example, gravure coat, reverse roll coat, die coat, air doctor coat, blade coat, rod coat, bar coat, curtain coat, knife coat, transfer roll coat, squeeze coat, impregnation Conventionally known coating methods such as a coat, a kiss coat, a spray coat, a calendar coat, and an extrusion coat can be used.

  The drying and curing conditions for forming the adhesive layer on the film are not particularly limited, but in the case of a coating method, the drying of a solvent such as water used in a coating solution is usually 70 to 70. The range is 150 ° C, preferably 80 to 130 ° C, more preferably 90 to 120 ° C. The drying time is generally in the range of 3 to 200 seconds, preferably 5 to 120 seconds. In order to improve the strength of the pressure-sensitive adhesive layer, a heat treatment step in the range of usually 180 to 270 ° C, preferably 200 to 250 ° C, and more preferably 210 to 240 ° C is performed in the film manufacturing process. The time of the heat treatment step is in the range of 3 to 200 seconds, preferably 5 to 120 seconds as a standard.

  If necessary, heat treatment and active energy ray irradiation such as ultraviolet irradiation may be used in combination. The film constituting the laminated polyester film in the present invention may be subjected to a surface treatment such as a corona treatment or a plasma treatment in advance.

  As the adhesive strength of the adhesive layer, the adhesive strength to a polymethyl methacrylate plate measured by a measuring method described later is preferably 1 to 5000 mN / cm, more preferably 3 to 1000 mN / cm, and still more preferably 5 to 1000 mN / cm. ５００500 mN / cm, particularly preferably 7 to 300 mN / cm, most preferably 10 to 100 mN / cm. By setting the above range, it is possible to achieve both the adhesive performance and the peeling performance to be peeled off after bonding, and it is possible to obtain an optimal laminate for various processes for performing the adhesive-peeling operation. . Further, the blocking characteristics of the film can be easily improved.

  The arithmetic average roughness (Sa) of the surface of the adhesive layer is preferably 50 nm or less, more preferably 30 nm or less, further preferably 20 nm or less, particularly preferably 15 nm or less, and most preferably 10 nm or less. If Sa is too high, sufficient adhesive strength may not be exhibited. When Sa is too high, the adhesive layer may need to be adjusted to a larger thickness in order to develop the adhesive strength, and the adjustment of the adhesive strength and the reduction of the migration of the adhesive component to the adherend may be required. It can be difficult. The lower limit is not particularly limited, but the lower limit of the preferred range is 1 nm.

  The Sa on the surface of the adhesive layer can be adjusted by the design of the adhesive layer or the design of the polyester film layer on the side in contact with the adhesive layer. If Sa is to be adjusted in the design of the adhesive layer, it is necessary to increase the thickness of the adhesive layer, and this raises the hurdle in designing the adhesive strength.

  As the design of the polyester film layer on the side of the adhesive layer, the average particle diameter of the contained particles, the content of the particles and the thickness of the polyester film layer are mainly cited as factors affecting Sa. Mainly, the value of Sa is determined by the interrelationship of these factors, so it is not possible to determine the value of Sa by considering only one factor. However, as a guideline for adjustment, the average particle size of the particles is usually 5 μm or less, preferably Is in the range of 3.5 μm or less. By using in the above range, it becomes easy to lower Sa.

  The amount of particles contained in the polyester film layer on the adhesive layer side is usually less than 0.30% by weight, preferably 0.15% by weight or less, more preferably 0.10% by weight or less, and particularly preferably 0.08% by weight. The range is as follows. By using in the above range, it becomes easy to lower Sa.

  The layer thickness of the polyester film layer on the side of the adhesive layer is usually in the range of 0.5 to 10 μm, preferably 1 to 8 μm, and more preferably 2 to 6 μm. Use in the above range facilitates adjustment of the content of the particles, and also facilitates adjustment of Sa.

  As described above, since the Sa on the surface of the adhesive layer depends on the design of the adhesive layer, it cannot be unconditionally determined. However, the Sa on the polyester surface from which the adhesive layer has been removed (the polyester surface when no adhesive layer is formed) is usually 50 nm. Or less, preferably 30 nm or less, more preferably 20 nm or less, particularly preferably 15 nm or less, and most preferably 10 nm or less. By using in the above range, Sa on the surface of the adhesive layer can be more easily adjusted.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. The measurement method and evaluation method used in the present invention are as follows.

(1) Measurement method of intrinsic viscosity of polyester 1 g of polyester from which other polymer components and pigments incompatible with polyester were removed was precisely weighed, and 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) was added. And dissolved at 30 ° C.

(2) Measurement method of average particle size (d50: μm) 50% integrated (weight basis) in equivalent spherical distribution measured using a centrifugal sedimentation type particle size distribution analyzer SA-CP3 manufactured by Shimadzu Corporation As the average particle size.

(3) Measurement method of arithmetic average roughness (Sa) The film surface was measured using a non-contact surface / layer cross-sectional shape measurement system VertScan (registered trademark) R550GML manufactured by Ryoka Systems Inc., and a CCD camera: SONY HR- 50 1/3 ', objective lens: 20 times, lens barrel: 1X Body, zoom lens: No Relay, wavelength filter: 530 white, measurement mode: Wave, and the output by fourth-order polynomial correction was used.

(4) Method of Measuring Film Thickness of Adhesive Layer and Functional Layer The surface of the adhesive layer or the functional layer was dyed with RuO ₄ and embedded in an epoxy resin. Thereafter, the section prepared by the ultrathin section method was stained with RuO ₄ , and the cross section of the adhesive layer was measured using a TEM (H-7650, manufactured by Hitachi High-Technologies Corporation, accelerating voltage 100 kV).

(5) Glass transition point Using a differential scanning calorimeter (DSC) 8500, manufactured by Perkin Elmer Japan Co., Ltd., the temperature was measured at -100 to 200 ° C. under a heating condition of 10 ° C./min.

(6) Number average molecular weight measurement method GPC was measured using GPC (manufactured by Tosoh Corporation, HLC-8120GPC). The number average molecular weight was calculated in terms of polystyrene.

(7-1) Adhesive strength evaluation method (Adhesive strength 1)
The adhesive layer surface of the laminated polyester film of the present invention having a width of 5 cm was reciprocated on a surface of a polymethyl methacrylate plate (como glass (registered trademark) manufactured by Kuraray Co., Ltd., 1 mm thick) with a 2 kg rubber roller having a width of 5 cm for 1 reciprocation. The peeling force after leaving for 1 hour was measured. As the peeling force, 180 ° peeling was performed under the condition of a tensile speed of 300 mm / min using “Ezgraph” manufactured by Shimadzu Corporation.

(7-2) Adhesive strength evaluation method (Adhesive strength 2)
Instead of using the polymethyl methacrylate plate of (7-1), the adhesive strength was evaluated using the polyester film surface (thickness 38 μm) without an adhesive layer obtained in Comparative Example 1 described later (7-1). The evaluation was performed in the same manner as in (1).

(8) Evaluation Method of Adhesive Layer Adhesion to Substrate One adhesive layer side of one A4 size laminated polyester film and an A4 size film having no adhesive layer of Comparative Example 1 described below are superimposed and strongly pressed with a finger. After sticking, the film having the adhesive layer was peeled off, and the surface of the film without the adhesive layer of Comparative Example 1 was observed. If there was no adhesive residue (transfer traces of the adhesive layer) (the adhesive layer and the original substrate Is good when the adhesiveness of the adhesive layer is good), and B when the adhesive residue remains (the adhesiveness of the adhesive layer is poor).

(9) Method for evaluating transferability of adhesive layer to adherend Adhesion of 5 cm-wide laminated polyester film of the present invention to the surface of a polymethyl methacrylate plate (como glass (registered trademark) manufactured by Kuraray Co., Ltd., thickness: 1 mm) The layer surface was pressed back and forth with a 2 kg rubber roller having a width of 5 cm for 2 reciprocations, attached and treated at 60 ° C. for 8 days, then the film was peeled off and the surface of the polymethyl methacrylate plate was observed.

  A indicates no trace on the polymethyl methacrylate plate (no migration of the adhesive layer is observed), B indicates a very slight trace observed when staring under a fluorescent lamp for 3 seconds, and B indicates a thin trace. C is observed when observed, D is observed when a clear white mark is partially observed at the end where the film is stuck (adhesive layer is transferred), and D is when a clear white mark is observed over the entire surface. E. In addition, when it does not stick to an adherend, it described as "-". In applications where migration is a concern, it is better to avoid D and E. In applications where low migration is required, the level of A or B, particularly the level of A, is preferred.

(10) Measuring method of minimum absolute reflectance from the surface of the functional layer A black tape (vinyl tape VT-50 manufactured by Nichiban Co., Ltd.) is pasted on the measurement back surface (adhesive layer surface) of the polyester film in advance, and a spectrophotometer (Nihon Bunko) Synchronous mode, incident angle 5 °, N-polarized light, response Fast, data collection interval 1.0 nm, bandwidth using an ultraviolet-visible spectrophotometer V-570 manufactured by Co., Ltd. and an automatic absolute reflectance measuring device AM-500N). The absolute reflectance of the functional layer surface in the wavelength range of 400 to 800 nm was measured at a scanning speed of 10 nm and a scanning speed of 1000 m / min, and the wavelength (bottom wavelength) and the absolute reflectance at the minimum value (minimum value) were evaluated. In the example, when the wavelength is plotted on the horizontal axis and the absolute reflectance is plotted on the vertical axis, the absolute reflectance in the wavelength range of 400 to 800 nm is a case where one minimum value is present, and Values were consistent with the local minimum.

(11) Method for evaluating the value of improvement in total light transmittance when affixed to an adherend The surface of a polymethyl methacrylate plate (comoglass (registered trademark) manufactured by Kuraray Co., Ltd., 1 mm thick) having a width of 5 cm according to the present invention The pressure-sensitive adhesive layer surface of the laminated polyester film is reciprocated by two reciprocations using a 2 cm rubber roller having a width of 5 cm, and is adhered. The total light transmittance is measured according to JIS K 7361 using a haze meter HM-150 manufactured by Murakami Color Research Laboratory Co., Ltd. Was measured.

The total light transmittance is preferably as high as possible, and is preferably 1.0% or more, more preferably 1.5% or more, and still more preferably 2.0%, as compared with the case where Comparative Example 12 having no functional layer is attached. Above, particularly preferably 2.5% or more, most preferably 3.0% or more.
If it is less than 1.0%, the transmittance may not be sufficient.

The polyester used in the examples , reference examples and comparative examples was prepared as follows.
<Production method of polyester (A)>
100 parts by weight of dimethyl terephthalate, 60 parts by weight of ethylene glycol, ethyl acid phosphate 30 ppm based on polyester produced, magnesium acetate tetrahydrate produced as catalyst 100 ppm based on polyester at 260 ° C. under nitrogen atmosphere at 260 ° C. Reaction. Subsequently, 50 ppm of tetrabutyl titanate was added to the resulting polyester, the temperature was raised to 280 ° C. over 2 hours and 30 minutes, the pressure was reduced to an absolute pressure of 0.3 kPa, and the melt polycondensation was further performed for 80 minutes to obtain an intrinsic viscosity. A polyester (A) having 0.63 and a diethylene glycol content of 2 mol% was obtained.

<Production method of polyester (B)>
Dimethyl terephthalate (100 parts by weight), ethylene glycol (60 parts by weight), and magnesium acetate tetrahydrate as a catalyst 900 ppm of the polyester based on the polyester were subjected to an esterification reaction at 225 ° C. in a nitrogen atmosphere. Subsequently, orthophosphoric acid was added to the produced polyester in an amount of 3500 ppm, and germanium dioxide was added to the produced polyester in an amount of 70 ppm. The temperature was raised to 280 ° C. over 2 hours and 30 minutes, and the pressure was reduced to an absolute pressure of 0.4 kPa. The polyester was melt-polycondensed for 85 minutes to obtain a polyester (B) having an intrinsic viscosity of 0.64 and a diethylene glycol content of 2 mol%.

<Production method of polyester (C)>
Polyester (C) is obtained by the same method as that for producing polyester (A) except that 0.3 parts by weight of silica particles having an average particle size of 2 μm is added before melt polymerization. Was.

<Production method of polyester (D)>
A polyester (D) is produced by the same method as that for producing the polyester (A) except that 0.6 parts by weight of silica particles having an average particle size of 3.2 μm is added before the melt polymerization. I got

Examples of compounds constituting the adhesive layer and the functional layer are as follows.
(Compound example)
・ Polyester resin: (IA)
Aqueous dispersion of a polyester resin having the following composition (glass transition point: -20 ° C) Monomer composition: (acid component) dodecanedicarboxylic acid / terephthalic acid / isophthalic acid / 5-sodium sulfoisophthalic acid // (diol component) ethylene Glycol / 1,4-butanediol = 20/38/38/4 // 40/60 (mol%)
・ Polyester resin: (IB)
Aqueous dispersion of a polyester resin having the following composition (glass transition point: -30 ° C) Monomer composition: (acid component) dodecanedicarboxylic acid / terephthalic acid / isophthalic acid / 5-sodium sulfoisophthalic acid // (diol component) ethylene Glycol / 1,4-butanediol = 30/33/33/4 // 40/60 (mol%)

・ Acrylic resin: (IC)
Aqueous dispersion of acrylic resin (glass transition point: -50 ° C) having the following composition 2-ethylhexyl acrylate / methyl methacrylate / methacrylic acid = 85/12/3 (% by weight)
・ Acrylic resin: (ID)
Aqueous dispersion of acrylic resin (glass transition point: -55 ° C) having the following composition 2-ethylhexyl acrylate / normal butyl acrylate / methyl methacrylate / 2-hydroxyethyl methacrylate = 77/10/5/8 (% by weight)
・ Acrylic resin: (IE)
Aqueous dispersion of acrylic resin (glass transition point: -25 ° C) having the following composition: normal butyl acrylate / styrene / acrylic acid = 62/35/3 (% by weight)
・ Acrylic resin: (IF)
Aqueous dispersion of acrylic resin (glass transition point: -40 ° C) having the following composition 2-ethylhexyl acrylate / normal butyl acrylate / methyl methacrylate / 2-hydroxyethyl methacrylate / acrylic acid = 58/20/15/5 / 2 (% by weight)

・ Acrylic resin: (IG)
Aqueous dispersion of acrylic resin (glass transition point: -40 ° C) having the following composition: normal butyl acrylate / 2-ethylhexyl acrylate / acrylonitrile / acrylic acid = 82/10/5/3 (% by weight)
・ Acrylic resin: (IH)
Aqueous dispersion of acrylic resin (glass transition point: -50 ° C.) having the following composition 2-ethylhexyl acrylate / normal butyl acrylate / ethyl acrylate / 2-hydroxyethyl methacrylate / acrylic acid = 50/27/15/5 / 3 (% by weight)

・ Urethane resin: (IK)
Aqueous dispersion of urethane resin (glass transition point: -30 ° C) having the following composition: 1,6-hexanediol and diethyl carbonate, polycarbonate polyol having a number average molecular weight of 2000 / polyethylene glycol having a number average molecular weight of 400 / butanediol / Isophorone diisocyanate / dimethylolpropionic acid = 83/2/2/11/2 (% by weight)

-Melamine compound: (IIA) hexamethoxymethylol melamine-Isocyanate compound: (IIB)
1,000 parts of hexamethylene diisocyanate was stirred at 60 ° C., and 0.1 part of tetramethylammonium caprylate was added as a catalyst. Four hours later, 0.2 parts of phosphoric acid was added to stop the reaction, and an isocyanurate-type polyisocyanate composition was obtained. 100 parts of the obtained isocyanurate-type polyisocyanate composition, 42.3 parts of methoxypolyethylene glycol having a number average molecular weight of 400, and 29.5 parts of propylene glycol monomethyl ether acetate were charged and kept at 80 ° C. for 7 hours. Thereafter, the temperature of the reaction solution was maintained at 60 ° C., and 35.8 parts of methyl isobutanoyl acetate, 32.2 parts of diethyl malonate, and 0.88 part of a 28% methanol solution of sodium methoxide were added, and the mixture was maintained for 4 hours. 58.9 parts of n-butanol were added, the reaction solution was kept at a temperature of 80 ° C. for 2 hours, and then blocked polyisocyanate with active methylene obtained by adding 0.86 parts of 2-ethylhexyl acid phosphate.

・ Oxazoline compound: (IIC)
Acrylic polymer Epocloth having oxazoline groups and polyalkylene oxide chains (oxazoline group amount = 4.5 mmol / g, manufactured by Nippon Shokubai Co., Ltd.)
Epoxy compound: (IID) polyglycerol polyglycidyl ether, which is a polyfunctional polyepoxy compound

・ Polyester resin: (IIIA)
Aqueous dispersion of polyester resin (glass transition point: 30 ° C.) having the following composition Monomer composition: (acid component) terephthalic acid / isophthalic acid / 5-sodium sulfoisophthalic acid // (diol component) ethylene glycol / 1,4 -Butanediol / diethylene glycol = 40/56/4 // 45/25/30 (mol%)
・ Polyester resin: (IIIB)
Aqueous dispersion of polyester resin having the following composition (glass transition point: 50 ° C.) Monomer composition: (acid component) terephthalic acid / isophthalic acid / 5-sodium sulfoisophthalic acid // (diol component) ethylene glycol / 1,4 -Butanediol / diethylene glycol = 50/46/4 // 70/20/10 (mol%)

・ Acrylic resin: (IIIC)
Aqueous dispersion of acrylic resin (glass transition point: 10 ° C.) having the following composition: normal butyl acrylate / ethyl acrylate / methyl methacrylate / 2-hydroxyethyl methacrylate / acrylic acid = 10/52/30/5/3 (% by weight)
・ Acrylic resin: (IIID)
Aqueous dispersion of acrylic resin (glass transition point: 40 ° C.) having the following composition Ethyl acrylate / methyl methacrylate / N-methylolacrylamide / acrylic acid = 48/45/4/3 (% by weight)

・ Urethane resin: (IIIE)
Aqueous dispersion of urethane resin (glass transition point: 50 ° C.) having the following composition: isophorone diisocyanate / terephthalic acid / isophthalic acid / ethylene glycol / diethylene glycol / dimethylolpropanoic acid = 12/19/18/21/25/5 (mol) %)
・ Polyester resin: (IIIF)
Water dispersion of polyester resin copolymerized with the following composition Monomer composition: (acid component) 2,6-naphthalenedicarboxylic acid / 5-sodium sulfoisophthalic acid // (diol component) ethylene glycol / diethylene glycol = 92/8 // 80/20 (mol%)

-Particles: (IVA) Silica particles having an average particle diameter of 45 nm-Particles: (IVB) Silica particles having an average particle diameter of 200 nm

・ Release agent (long chain alkyl group-containing compound): (VA)
200 parts of xylene and 600 parts of octadecyl isocyanate were added to a four-neck flask and heated with stirring. From the time when xylene started to reflux, 100 parts of polyvinyl alcohol having an average polymerization degree of 500 and a saponification degree of 88 mol% were added little by little at intervals of 10 minutes over about 2 hours. After the completion of the addition of the polyvinyl alcohol, the reaction was further refluxed for 2 hours to complete the reaction. The reaction mixture was cooled to about 80 ° C. and then added to methanol. As a result, the reaction product precipitated as a white precipitate. The precipitate was separated by filtration, and 140 parts of xylene was added. After that, the operation of adding methanol again to precipitate was repeated several times, and then the precipitate was washed with methanol, and dried and pulverized to obtain a precipitate.

・ Wax: (VB)
A 1.5-liter emulsifying equipment equipped with a stirrer, thermometer and temperature controller was placed in a 1.5-liter emulsifying apparatus, melting point 105 ° C., acid value 16 mg KOH / g, density 0.93 g / mL, 300 g of polyethylene oxide wax having a number average molecular weight of 5000, and 650 g of ion-exchanged water. After adding 50 g of decaglycerin monooleate surfactant and 10 g of a 48% aqueous potassium hydroxide solution, replacing with nitrogen, sealing, stirring at high speed at 150 ° C. for 1 hour, cooling to 130 ° C., and using a high-pressure homogenizer under 400 atm. Wax emulsion cooled down to 40 ° C.

Example 1
A mixed raw material obtained by mixing the polyesters (A), (B), and (C) at a ratio of 91%, 3%, and 6%, respectively, was used as a raw material for the outermost layer (surface layer), and the polyesters (A) and (B) were 97% each. % And 3% as a raw material for the intermediate layer, each was supplied to two extruders, each of which was melted at 285 ° C., and then cooled on a cooling roll set at 40 ° C. to obtain a mixture of three kinds. Coextrusion was carried out in a layer configuration of layers (surface layer / intermediate layer / surface layer = discharge amount of 3: 32: 3), and the mixture was cooled and solidified to obtain an unstretched sheet.
Next, the film is stretched 3.2 times in the machine direction at a film temperature of 85 ° C. using a difference in roll peripheral speed, and then a coating solution A1 shown in Table 1 below is coated on one surface of the machine-stretched film with the thickness of the adhesive layer (drying). (After) is applied so as to have a thickness of 90 nm, and a coating solution B1 shown in Table 3 below is applied to the opposite surface so that the functional layer has a thickness (after drying) of 100 nm, and is guided to a tenter. After dried for 10 seconds, stretched 4.3 times in the horizontal direction at 120 ° C., and heat-treated at 230 ° C. for 10 seconds, relaxed 2% in the horizontal direction, thickness of 38 μm, and Sa on the surface of the adhesive layer. A 9 nm polyester film was obtained. When the adhesive layer was removed with ethyl acetate, Sa on the polyester surface on the side where the adhesive layer was located was 9 nm.

  When the obtained polyester film was evaluated, the adhesive strength with the polymethyl methacrylate plate was 10 mN / cm, the adhesive property was good, and the minimum value of the absolute reflectance on the functional layer side was as low as 2.2%. The light transmittance was high and good. The properties of this film are shown in Table 4 below.

Examples 2-239:
A polyester film was obtained in the same manner as in Example 1, except that the coating composition was changed to the coating compositions shown in Tables 1 to 3. As shown in the following Tables 4 to 10, the obtained polyester film had good adhesive strength, a low minimum value of the absolute reflectance on the functional layer side, and was good enough to improve the total light transmittance.

Example 240:
A mixed raw material obtained by mixing polyesters (A), (B), and (D) at a ratio of 87%, 3%, and 10%, respectively, was used as a raw material for the outermost layer (surface layer), and polyester (A) and (B) were each 97%. % And 3% as a raw material for the intermediate layer, each was supplied to two extruders, each of which was melted at 285 ° C., and then cooled on a cooling roll set at 40 ° C. to obtain a mixture of three kinds. Coextrusion was performed in a layer configuration of layers (surface layer / intermediate layer / surface layer = discharge amount of 6: 26: 6), followed by cooling and solidification to obtain an unstretched sheet. Next, the film is stretched 3.2 times in the machine direction at a film temperature of 85 ° C. using a difference in roll peripheral speed, and then a coating solution A1 shown in Table 1 below is coated on one surface of the machine-stretched film with the thickness of the adhesive layer (drying). (After) is applied so as to have a thickness of 150 nm, and a coating solution B1 shown in Table 3 below is applied to the opposite surface so that the functional layer has a thickness (after drying) of 100 nm, and is guided to a tenter. After dried for 10 seconds, stretched 4.3 times in the horizontal direction at 120 ° C., and heat-treated at 230 ° C. for 10 seconds, relaxed 2% in the horizontal direction, thickness of 38 μm, and Sa on the surface of the adhesive layer. A 15 nm polyester film was obtained. In addition, when the adhesive layer was removed with ethyl acetate, Sa on the polyester surface on the side where the adhesive layer was located was 15 nm.

  When the obtained polyester film was evaluated, the adhesive strength with the polymethyl methacrylate plate was 20 mN / cm, the adhesive property was good, and the minimum value of the absolute reflectance on the functional layer side was as low as 2.2%. The light transmittance was high and good. The properties of this film are shown in Table 11 below.

Examples 241-260:
A polyester film was obtained in the same manner as in Example 240 except that the coating composition was changed to the coating compositions shown in Tables 1 to 3. As shown in Table 11 below, the obtained polyester film had a good adhesive strength, a low absolute value of the absolute reflectance on the functional layer side, and was a good film capable of improving the total light transmittance.

Reference Example 261:
A polyester film was obtained in the same manner as in Example 1, except that the adhesive layer was not provided. On this polyester film without the adhesive layer, a coating solution A21 shown in Table 1 below is applied so that the thickness (after drying) of the adhesive layer becomes 100 nm, dried at 100 ° C. for 60 seconds, and subjected to off-line coating. A polyester film having an adhesive layer laminated thereon was obtained. As shown in Table 11, the obtained polyester film had a good adhesive strength and a low absolute reflectance on the functional layer side, which was good. However, the adhesion of the adhesive layer to the substrate and the transferability to the adherend were not good.

Reference Example 262:
In Reference Example 261, a polyester film was obtained in the same manner as in Reference Example 261, except that the composition of the pressure-sensitive adhesive layer was changed to the composition shown in Table 2. As shown in Table 11 below, the obtained polyester film had good adhesive strength and a low absolute value of the absolute reflectance on the functional layer side, which was good. However, the adhesiveness of the adhesive layer to the substrate and the adherence to the adherend were good. Was not good.

Comparative Example 1:
A polyester film was obtained in the same manner as in Example 1 except that the adhesive layer and the functional layer were not provided. When the obtained polyester film was evaluated, as shown in Table 12 below, it was a film having no tackiness and having a high minimum absolute reflectance.

Comparative Examples 2 to 12:
A polyester film was obtained in the same manner as in Example 1, except that the coating composition was changed to the coating compositions shown in Tables 1 to 3. As shown in Table 12, when the obtained polyester film has no adhesive strength, or has a high absolute value of the absolute reflectance on the functional layer side (the opposite side of the film from the adhesive layer), and is bonded to the adherend. The improvement of the transmittance of the film was a low result, and there was a case where there was a concern about the inspection of foreign matter by an apparatus or the like.

Comparative Example 13:
On the polyester film without the adhesive layer and the functional layer obtained in Comparative Example 1, a coating solution A21 shown in Table 1 below was applied at 100 ° C. for 3 minutes so that the film thickness (after drying) of the adhesive layer became 20 μm. Drying was performed to obtain a polyester film on which an adhesive layer was formed by off-line coating. When cutting was performed after bonding the adhesive layer side to the polyester film, the components of the adhesive layer, which were not seen in the examples, protruded, and the result was that there was concern about contamination by the adhesive component. In addition, the adhesion could not be measured well. Other characteristics are as shown in Table 12.

  The film of the present invention is, for example, a resin plate, a metal plate or the like, in the use of a surface protection film or the like used for prevention of scratches or dirt adhesion during storage or processing during storage, processing, etc. It can be suitably used for applications that require excellent adhesive strength and heat resistance, and have good adhesive properties and permeability.

Claims (8)

On one surface of the polyester film, contains an acrylic resin having a glass transition point of 0 ℃ or less (excluding fluorine-based polymer), a film thickness with an adhesive layer is 10μm or less, viscosity Chakusochu of A acrylic resin the content is 45 wt% or more, the polyester film surface on the side opposite to the pressure-sensitive adhesive layer, Ru a function layer minimum value of absolute reflectance is less than 4.0% in the wavelength range of 400~800nm laminate A method for producing a polyester film ,
Producing an adhesive layer on one surface of a polyester film, providing a functional layer on the polyester film surface opposite to the adhesive layer, and then stretching the adhesive layer and the functional layer together with the polyester film, producing a laminated polyester film. How . On one surface of a polyester film, a glass transition point of 0 ℃ or less, containing a polyester resin or urethane resin, thickness comprises an adhesive layer is 10μm or less, viscosity Chakusochu the port Riesuteru resin or urethane resin the content is 45 wt% or more, the polyester film surface on the side opposite to the pressure-sensitive adhesive layer, Ru a function layer minimum value of absolute reflectance is less than 4.0% in the wavelength range of 400~800nm laminate A method for producing a polyester film ,
Producing an adhesive layer on one surface of a polyester film, providing a functional layer on the polyester film surface opposite to the adhesive layer, and then stretching the adhesive layer and the functional layer together with the polyester film, producing a laminated polyester film. How . The method for producing a laminated polyester film according to claim 1, wherein the pressure-sensitive adhesive layer is formed through a heat treatment step in a range of 180 to 270 ° C. 4. The method for producing a laminated polyester film according to any one of claims 1 to 3, wherein the adhesive layer is formed by applying and drying an aqueous solution or a water dispersion. The method for producing a laminated polyester film according to any one of claims 1 to 4, wherein the thickness of the adhesive layer is in a range of 1 nm to 2500 nm. The method for producing a laminated polyester film according to any one of claims 1 to 5, wherein the arithmetic average roughness (Sa) of the adhesive layer side surface of the polyester film is 50 nm or less. The method for producing a laminated polyester film according to any one of claims 1 to 6, wherein the pressure-sensitive adhesive layer is formed using a coating solution containing a crosslinking agent. The method for producing a laminated polyester film according to any one of claims 1 to 7, wherein the functional layer contains at least one selected from a long-chain alkyl group-containing compound, a silicone compound, and a wax.