JP2021076806A - Manufacturing method of laminated polarization film - Google Patents

Abstract

To provide a manufacturing method of a laminated polarization film in which a polarizer and a protective film are excellently adhered with an adhesive agent interposed therebetween.SOLUTION: A manufacturing method of a laminated polarization film includes: an adhesive agent coating step of coating a protective film 12 with an adhesive agent 65 using a coating roll 641; and a laminate step of bonding a polarizer 1c and the protective film 12 coated with the adhesive agent 65 by passing through a nip roll 671. The protective film 12 at an exit side of the coating roll 641 in the adhesive agent coating step is to be within a range of 20°C to 35°C, and the protective film 12 at an exit side of the nip roll 671 in the laminate step is to be within a range of 20°C to 35°C.SELECTED DRAWING: Figure 4

Description

The present invention relates to a method for producing a laminated polarizing film by adhering a polarizing element and a protective film via an adhesive.

Conventionally, a laminated polarizing film containing a polarizer has been used as a constituent material of a liquid crystal display device, polarized sunglasses, and the like. As the laminated polarizing film, for example, a film containing a polarizing element dyed with a dichroic substance such as iodine and a protective film for protecting the polarizing element is used.
Such a laminated polarizing film can be obtained, for example, by adhering a protective film to one side or both sides of a polarizer with a specific adhesive, as described in Patent Documents 1 and 2.
Specifically, in Patent Documents 1 and 2, a polyvinyl alcohol-based resin film is stretched while being dyed with an iodine solution and washed with water to produce a polarizing element, and a protective film is attached to the polarizing element via an adhesive. It is disclosed that a laminated polarizing film is obtained by laminating the two.

Japanese Unexamined Patent Publication No. 2014-129505 JP-A-2018-127610

However, if the protective film with the adhesive is attached to the polarizer after applying the adhesive to the protective film, the adhesive may impregnate the protective film too much, in which case the adhesive will It does not cure well and may partially peel off between the layers with the adhesive. On the other hand, if the adhesive does not impregnate the protective film too much, the adhesive does not adhere well to the protective film and may be partially peeled off between the layers with the adhesive.

An object of the present invention is to provide a method for producing a laminated polarizing film in which a polarizer and a protective film are well bonded via an adhesive.

The method for producing a laminated polarizing film of the present invention is an adhesive coating step in which an adhesive is applied to a protective film using a coating roll, and the protective film and the polarizer coated with the adhesive are passed through a nip roll. The protective film on the outlet side of the coating roll in the adhesive coating step is in the range of 20 ° C. to 35 ° C., and is on the outlet side of the nip roll in the lamination step. The protective film is in the range of 20 ° C to 35 ° C.

The preferred production method of the present invention is a transparent film in which the protective film has a surface that is easily adhered to the adhesive.
In the preferred production method of the present invention, the protective film is a triacetyl cellulose film.
The preferred production method of the present invention is a urethane-based film with an easy-adhesive adhesive.
The preferred production method of the present invention is an acrylic film with a urethane-based easy adhesive.
In the preferred production method of the present invention, the adhesive is an active energy ray-curable adhesive.
In the preferred production method of the present invention, the adhesive is applied to the protective film to a thickness of 0.1 μm to 5 μm.
In the preferred production method of the present invention, the polarizing element is attached to the protective film within 2 to 30 seconds after the adhesive is applied to the protective film.
The preferred manufacturing method of the present invention holds the protective film between the outlet side of the coating roll and the outlet side of the nip roll in the range of 20 ° C. to 35 ° C.

According to the production method of the present invention, it is possible to produce a laminated polarizing film in which a polarizer and a protective film are well bonded via an adhesive.

Sectional drawing of the laminated polarizing film which concerns on one Embodiment of this invention. Sectional drawing of the laminated polarizing film which concerns on other embodiment of this invention. Sectional drawing of the laminated polarizing film which concerns on other embodiment of this invention. The schematic which shows the manufacturing apparatus of the laminated polarizing film of this invention.

In the present specification, the numerical range represented by "lower limit value X to upper limit value Y" means a lower limit value X or more and an upper limit value Y or less. When a plurality of the numerical values are described separately, it is possible to select an arbitrary lower limit value and an arbitrary upper limit value and set "arbitrary lower limit value to arbitrary upper limit value".
It should be noted that each figure is shown for reference only, and the dimensions, scale and shape of the members etc. shown in each figure may differ from the actual ones.

[Laminated polarizing film]
The laminated polarizing film obtained by the production method of the present invention has a polarizer and a protective film adhered to at least one surface of the polarizer using an adhesive layer.
1 to 3 show some configuration examples of the laminated polarizing film 1 obtained by the production method of the present invention.
In FIG. 1, the laminated polarizing film 1 of one embodiment of the present invention includes a first protective film 12, an adhesive layer 31, a polarizer 11, an adhesive layer 32, and a second protective film 13. They are stacked in this order.
In FIG. 2, the laminated polarizing film 1 of another embodiment of the present invention includes a protective film 12, an adhesive layer 31, a polarizer 11, an adhesive layer 33, and an arbitrary optical film 14 in this order. It is laminated with.
In FIG. 3, the laminated polarizing film 1 of another embodiment of the present invention adheres to the first protective film 12, the adhesive layer 31, the polarizer 11, the adhesive layer 32, and the second protective film 13. The agent layer 34 and the optional optical film 14 are laminated in this order.
However, the laminated polarizing film of the present invention is not limited to the configuration examples of FIGS. 1 to 3, and can be appropriately changed.
For example, one or more arbitrary other optical films may be further laminated on the laminated polarizing film of each of the above-mentioned configuration examples.

<Polarizer>
A polarizer is an optical element that has the property of transmitting light (polarized light) that vibrates in only one specific direction and blocking light that vibrates in the other direction. The polarizer of the present invention is in the form of a flexible film.
Specifically, the polarizer of the present invention is produced by a wet treatment described later. The polarizer consists of a hydrophilic polymer film dyed and stretched with a dichroic substance (for example, a polyvinyl alcohol-based film dyed and stretched with a dichroic substance).

<Protective film>
The protective film is a film provided to protect the polarizer. As the protective film, a colorless and transparent film can be used.
As the colorless and transparent protective film, for example, a triacetyl cellulose film (TAC film), an acrylic film (a film using an acrylic polymer), a polyethylene terephthalate film, a cycloethylene film or a polyolefin film having a norbornene structure can be used. ..
As the protective film, it is preferable to use a transparent film having a surface that is easily adhered to an adhesive (particularly, an active energy ray-curable adhesive described later).
The transparent film having an easily adhesive surface easily mixes with the adhesive or easily penetrates the adhesive on the surface.
A transparent film having an easily adhesive surface to an adhesive is (a) a film in which the film itself is made of a material having an easy adhesive property to an adhesive, and (b) a film itself having an easy adhesive property to an adhesive. A film that is made of a material and whose surface is easily adhered. (C) The film itself is made of a material that is difficult to adhere to an adhesive. Examples thereof include a film whose surface is easily adhered.
Examples of the transparent film (a) include a TAC film and an acrylic film.
As the transparent film of (b) or (c), a film (protective film with easy adhesive) coated with an easy adhesive on at least one side of any transparent film, or a film coated with an easy adhesive composition. (Film with easy adhesive layer) and the like. The easy-adhesive is not particularly limited, but it is preferable to use an easy-adhesive containing a urethane resin because it has excellent adhesion to an active energy ray-curable adhesive.
Examples of the easy-adhesion composition include an easy-adhesion composition coated on a polarizer and the like, as will be described later.

<Optical film>
As the arbitrary optical film, conventionally known ones can be used, and examples thereof include a retardation film, an antiglare film, a brightness improving film, a viewing angle improving film, and a transparent conductive film.

<Adhesive layer>
The adhesive layer is a solidifying layer of an adhesive, which is a layer interposed between two films and adhering the two films.
With reference to FIGS. 1 to 3, the adhesive layers 31 and 32 for adhering the polarizer 11 and the protective film 12, the adhesive layer 33 for adhering the polarizer 11 and the optical film 14, and the protective film 13. The adhesive layer 34 for adhering the optical film 14 is not particularly limited, and is composed of a conventionally known adhesive. Examples of the adhesive include solvent-volatile adhesives, two-component reaction adhesives, and active energy ray-curable adhesives. Preferably, an active energy ray-curable adhesive can be used. The active energy ray-curable adhesive is preferably used at least when adhering the polarizer and the protective film.
For example, in the case of the laminated polarizing films 1 of FIGS. 1 and 3, it is preferable that the adhesive layers 31 and 32 are all composed of an active energy ray-curable adhesive. In the case of the laminated polarizing film 1 of FIG. 2, the adhesive layer 31 is preferably composed of an active energy ray-curable adhesive. The adhesive layers 33 and 34 may be composed of an active energy ray-curable adhesive or other adhesives, but the active energy ray-curable adhesive is preferable. Consists of.
The active energy ray-curable adhesive will be described in detail later.

[Manufacturing equipment for polarizers and manufacturing equipment for laminated polarizing films]
The polarizer manufacturing apparatus of the present invention includes a wet treatment apparatus for producing a long strip-shaped polarizer by dyeing and stretching a long strip-shaped hydrophilic polymer film with a dyeing treatment liquid, and the wet treatment apparatus. It has a drying device for drying the obtained polarizer.
Further, the apparatus for producing a laminated polarizing film of the present invention includes a wet processing apparatus for producing a long strip-shaped polarizing element by dyeing and stretching a long strip-shaped hydrophilic polymer film with a dyeing treatment liquid, and the wet treatment apparatus. It has a drying device for drying the polarizer obtained by the processing device, and a laminating device for laminating the polarizer and the protective film.

In the polarizer manufacturing apparatus, a long strip-shaped polarizer is produced from a long strip-shaped hydrophilic polymer film by a wet processing apparatus, and then the polarizer is continuously dried by a drying apparatus. That is, the wet processing device and the drying device are arranged on one production line.
The laminated polarizing film manufacturing apparatus may be of a type in which a protective film is continuously adhered to a polarizing element dried by the polarizing element manufacturing apparatus by a laminating apparatus. Alternatively, the laminated polarizing film manufacturing apparatus is a type in which the polarizing element dried by the polarizing element manufacturing apparatus is once wound into a roll shape, the roll-shaped polarizing element is pulled out, and the protective film is adhered by the laminating apparatus. But it may be. The former form is a form in which a series of steps from the manufacture of the polarizer to the bonding of the protective film to obtain the laminated polarizing film is performed on one production line, and the latter form is the form in which the polarizer is manufactured in one. This is a format in which a step of performing on a production line and adhering a protective film to the polarizing element to obtain a laminated polarizing film is performed on another production line.
The laminated polarizing film manufacturing apparatus of the present invention preferably has a form in which a series of steps from manufacturing a polarizer to adhering a protective film to obtain a laminated polarizing film is performed on one production line. In the production device for the laminated polarizing film of this type, a polarizing element manufacturing device having a wet processing device and a drying device, and a laminating device are arranged on one production line.

FIG. 4 shows a preferable configuration example of the laminated polarizing film manufacturing apparatus 2.
With reference to FIG. 4, the laminated polarizing film manufacturing apparatus 2 includes a wet processing apparatus 4, a drying apparatus 5, and a laminating apparatus 6 in this order from the upstream side.
The wet treatment apparatus 4 has a first roll portion 41 around which a long strip-shaped untreated hydrophilic polymer film 1a is wound, a transport portion 42 for transporting the hydrophilic polymer film 1a, and a treatment portion. .. The treated portion is a portion where the untreated hydrophilic polymer film 1a is treated with a dichroic substance to change the hydrophilic polymer film 1a into a polarizer 1b.
The drying device 5 has a transport unit 51 that conveys a long strip-shaped polarizer 1b, and a heating portion that heats the polarizer 1b to dry the polarizer 1b.
The laminating device 6 includes a transport unit 61 that conveys the dried polarizer 1c and the protective film 12, an adhesive coating unit 64, a bonding unit 67, and the adhesive coating unit 64 and the bonding unit 67. It has a chamber 69 and a surrounding chamber 69.

<Wet processing equipment>
The wet treatment apparatus 4 includes a treatment portion for dyeing and stretching a long strip-shaped hydrophilic polymer film 1a with a dyeing treatment liquid. The wet treatment includes a treatment of stretching the hydrophilic polymer film 1a while allowing a plurality of treatment liquids including a dyeing treatment liquid to act on the hydrophilic polymer film 1a.
The wet treatment apparatus is conventionally known, and the wet treatment apparatus 4 of the present invention can also adopt the conventionally known configuration.
The treatment unit includes, for example, a swelling treatment tank 4A, a dyeing treatment tank 4B, a cross-linking treatment tank 4C, a stretching treatment tank 4D, and a cleaning treatment tank 4E in order from the upstream side.
The transport section 42 of the wet treatment device 4 has a plurality of guide rolls and the like, and draws out a long strip-shaped hydrophilic polymer film 1a wound around the first roll section 41 and transports the film 1a to the treatment section.
The white arrows in FIG. 4 indicate the traveling direction (conveying direction) of the film to be conveyed.

The hydrophilic polymer film 1a has a long strip shape. In the present specification, the long strip shape means a rectangular shape whose length in the longitudinal direction is sufficiently larger than the length in the width direction (the width direction is a direction orthogonal to the longitudinal direction). The length of the long strip in the longitudinal direction is, for example, 10 m or more, preferably 50 m or more.
The hydrophilic polymer film 1a is not particularly limited, and conventionally known films can be used. Specifically, examples of the hydrophilic polymer film 1a include polyvinyl alcohol (PVA) -based films, partially formalized PVA-based films, polyethylene terephthalate (PET) films, ethylene / vinyl acetate copolymer films, and partial kens thereof. Examples include chemical films. In addition to these, polyene-oriented films such as a dehydrated product of PVA and a dehydrochlorinated product of polyvinyl chloride, a stretch-oriented polyvinylene-based film, and the like can also be used. Among these, a PVA-based polymer film is particularly preferable because it is excellent in dyeability with a dichroic substance.
As the raw material polymer of the PVA-based polymer film, for example, a polymer obtained by polymerizing vinyl acetate and then saponified, or a copolymerizable monomer such as a small amount of unsaturated carboxylic acid or unsaturated sulfonic acid is copolymerized with vinyl acetate. Polymers, etc. The degree of polymerization of the PVA-based polymer is not particularly limited, but is preferably 500 to 10000, more preferably 1000 to 6000, from the viewpoint of solubility in water and the like. The degree of saponification of the PVA-based polymer is preferably 75 mol% or more, more preferably 98 mol% to 100 mol%.
The thickness of the untreated hydrophilic polymer film 1a is not particularly limited, but is, for example, 15 μm to 110 μm.

The swelling treatment tank 4A is a treatment tank containing the swelling treatment liquid. The swelling treatment liquid swells the hydrophilic polymer film 1a. As the swelling treatment liquid, for example, water can be used. Further, water obtained by adding an appropriate amount of an iodine compound such as glycerin or potassium iodide to water may be used as the swelling treatment liquid. When glycerin is added, the concentration is preferably 5% by weight or less, and when an iodine compound such as potassium iodide is added, the concentration is preferably 10% by weight or less.

The dyeing treatment tank 4B is a treatment tank containing a dyeing treatment liquid. The dyeing solution dyes the hydrophilic polymer film 1a. Examples of the dyeing solution include a solution containing a dichroic substance as an active ingredient. Examples of the dichroic substance include iodine and organic dyes. Preferably, as the dyeing treatment liquid, a solution in which iodine is dissolved in a solvent can be used. Water is generally used as the solvent, but an organic solvent compatible with water may be further added. The concentration of iodine in the dyeing solution is not particularly limited, but is preferably 0.01% by weight to 10% by weight, more preferably 0.02% by weight to 7% by weight, and 0.025% by weight. It is more preferably% to 5% by weight. If necessary, an iodine compound may be added to the dyeing solution in order to further improve the dyeing efficiency. The iodine compound is a compound containing iodine and an element other than iodine in the molecule, and is, for example, potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, and iodine. Examples thereof include barium iodide, calcium iodide, tin iodide, and titanium iodide.

The cross-linking treatment tank 4C is a treatment tank containing a cross-linking treatment liquid. The cross-linking treatment liquid cross-links the dyed hydrophilic polymer film 1a. As the cross-linking treatment liquid, a solution containing a boron compound as an active ingredient can be used. For example, as the cross-linking treatment liquid, a solution in which a boron compound is dissolved in a solvent can be used. Water is generally used as the solvent, but an organic solvent compatible with water may be further added. Examples of the boron compound include boric acid and borax. The concentration of the boron compound in the cross-linking treatment liquid is not particularly limited, but is preferably 1% by weight to 10% by weight, more preferably 2% by weight to 7% by weight, and 2% by weight to 6% by weight. Is even more preferable. Further, since a polarizer having uniform optical characteristics can be obtained, an iodine compound may be added to the cross-linking treatment liquid, if necessary.

The stretching treatment tank 4D is a treatment tank containing the stretching treatment liquid.
The stretching treatment liquid is not particularly limited, but for example, a solution containing a boron compound as an active ingredient can be used. As the stretching treatment liquid, for example, a solution in which a boron compound and, if necessary, various metal salts, zinc compounds and the like are dissolved in a solvent can be used. Water is generally used as the solvent, but an organic solvent compatible with water may be further added. The concentration of the boron compound in the stretching treatment liquid is not particularly limited, but is preferably 1% by weight to 10% by weight, more preferably 2% by weight to 7% by weight. From the viewpoint of suppressing the elution of iodine adsorbed on the film, an iodine compound may be added to the stretching treatment liquid, if necessary.

The cleaning treatment tank 4E is a treatment tank in which the cleaning treatment liquid is stored. The cleaning treatment liquid cleans the hydrophilic polymer film 1a after stretching. The cleaning treatment liquid is a treatment liquid for cleaning a treatment liquid such as a dyeing treatment liquid or a cross-linking treatment liquid adhering to the hydrophilic polymer film 1a. As the cleaning treatment liquid, water such as ion-exchanged water, distilled water, and pure water is typically used.
In the illustrated example, the treatment unit has a swelling treatment tank 4A, a dyeing treatment tank 4B, a cross-linking treatment tank 4C, a stretching treatment tank 4D, and a cleaning treatment tank 4E, provided that the treatment unit has the dyeing treatment tank 4B. One or two of the treatment tanks may be omitted. On the other hand, the processing unit may further have an adjustment processing tank (not shown). The adjustment treatment tank is a treatment tank in which the adjustment treatment liquid is stored. Although not shown in FIG. 5, this adjustment treatment tank is provided between the cross-linking treatment tank 4C and the stretching treatment tank 4D, or between the stretching treatment tank 4D and the cleaning treatment tank 4E. The adjusting treatment liquid is a solution for adjusting the hue of a film, and a solution containing an iodine compound as an active ingredient can be used.

<Drying device>
The drying device 5 is provided on the downstream side of the wet processing device 4 and on the upstream side of the laminating device 6. In the illustrated example, the drying device 5 is provided on the downstream side of the cleaning treatment tank 4E.
One drying device 5 may be provided, or two or more drying devices 5 may be provided side by side in the conveying direction of the polarizer. In the illustrated example, for example, one drying device 5 is provided in the transport path of the polarizer.
The drying apparatus 5 is conveyed in the longitudinal direction (MD direction) by the conveying portion 51 having a guide roll for conveying the long strip-shaped polarizer 1b manufactured by the wet processing apparatus 4, and the conveying portion 51. It has a heating unit that applies heat to the polarizer 1b to dry it.
The heating unit has, for example, a chamber 52 and a heat source (not shown). The chamber 52 has a space 53 inside which the polarizer can be conveyed. As the heat source, for example, warm air can be used. A duct (not shown) for sending warm air is arranged on the inner wall of the chamber 52. Air (warm air) heated by a heat source (not shown) is sent out into the space 53 of the chamber 52 through the duct.
The polarizer 1b that has entered the space 53 from the slit-shaped inlet on the upstream side of the chamber 52 is dried by a heat source and then conveyed to the outside of the chamber 52 from the slit-shaped outlet on the downstream side of the chamber 52.

<Laminating device>
The transport section 61 of the laminating device 6 has a guide roll or the like. The transport section 61 transports the long strip-shaped polarizer 1c dried by the drying device 5 to the bonding section 67. Further, the transport section 61 transports a long strip-shaped protective film 12 or the like to the bonding section 67.
In the laminated polarizing film manufacturing apparatus 2 of the illustrated example, the first protective film 12 and the second protective film 13 can be laminated on both sides of the polarizer 1c, respectively. According to this apparatus, a laminated polarizing film 1 having a layer structure of a first protective film 12 / an adhesive layer 31 / a polarizer 11 / an adhesive layer 32 / a second protective film 13 as shown in FIG. 1 is obtained. Be done.

Such a manufacturing apparatus 2 has a second roll portion 62 around which the long strip-shaped first protective film 12 is wound, and a third roll portion 63 around which the long strip-shaped second protective film 13 is wound. .. The first protective film 12 of the second roll portion 62 and the second protective film 13 of the third roll portion 63 are independently conveyed from the roll portions 62 and 63 to the bonding portion 67 by the conveying portion 61, respectively. ..

The adhesive coating unit 64 has a coating roll 641. The coating roll 641 of the adhesive coating unit 64 coats the film with an adhesive. The adhesive coating portion 64 is arranged on the upstream side of the bonding portion 67.
In the laminating device 6 of the illustrated example, the adhesive coating portion 64 is arranged on one side of the first protective film 12 and one side of the second protective film 13, respectively.
An adhesive layer can be formed by applying an adhesive to one side of the first protective film 12 by one adhesive coating portion 64, and the other adhesive coating portion 64 can be applied to one side of the second protective film 13. The adhesive can be applied to form an adhesive layer.
If necessary, the adhesive coating portion may be arranged on one side of the polarizer 1c and on the other side of the polarizer 1c (not shown). When the adhesive coating portion (not shown) is provided, an adhesive can be applied to one side of the polarizer 1c and the other side of the polarizer 1c to form an adhesive layer.
Further, the adhesive coating portion arranged on one side of the polarizer 1c and the other side of the polarizer 1c can be used for coating the easy-adhesion composition described later.

The adhesive coating unit 64 has, for example, a gravure roll 641 which is a coating roll, a container 642 in which an adhesive is stored, and a doctor blade 643. If necessary, it may have a backup role. The backup roll is arranged so as to face the gravure roll roll 641 with the film interposed therebetween.
The gravure roll 641 has a plurality of cells (recesses in which an adhesive enters) formed on the surface thereof. The gravure roll 641 rotates about an axis so that its surface contacts the adhesive 65 stored in the container 642 (the direction of rotation of the gravure roll 641 is indicated by an arrow). As the rotation proceeds, the adhesive 65 adheres to the surface of the gravure roll 641 containing the cells, and the excess adhesive 65 is scraped into the container 642 by the doctor blade 643. When the gravure roll 641 containing the adhesive in the cell comes into contact with the film, the adhesive 65 in the cell is transferred to one side of the first protective film 12 and the second protective film 13. In this way, the adhesive 65 is applied to one side of the gravure roll 641 to the first protective film 12 and the second protective film 13 in a solid shape.

The adhesive for adhering the polarizer 1c to the first protective film 12 and the second protective film 13 is not particularly limited, but it is preferable to use an active energy ray-curable adhesive as described above. As the active energy ray-curable adhesive, conventionally known ones can be used. The active energy ray-curable adhesive generally contains an active energy ray-curable component and a polymerization initiator, and optionally contains various additives.
The active energy ray-curable component can be roughly classified into electron beam curability, ultraviolet curability, and visible light curability. Further, the active energy ray-curable component can be roughly classified into a radical-polymerizable compound and a cationically polymerizable compound from the viewpoint of the curing mechanism.

Examples of the radically polymerizable compound include compounds having a radically polymerizable functional group of a carbon-carbon double bond such as a (meth) acryloyl group and a vinyl group. Moreover, either a monofunctional radical polymerizable compound or a bifunctional or higher functional radical polymerizable compound can be used. Further, these radically polymerizable compounds may be used alone or in combination of two or more. The radically polymerizable compound is preferably a compound having a (meth) acryloyl group, and examples thereof include a (meth) acrylamide derivative having a (meth) acrylamide group and a (meth) acrylate having a (meth) acryloyloxy group. ..
When a radically polymerizable compound is used as the active energy ray-curable adhesive, the polymerization initiator is appropriately selected according to the active energy ray. When the adhesive is cured by ultraviolet rays or visible light, an ultraviolet cleaving or visible light cleaving polymerization initiator is used. Examples of such a polymerization initiator include benzophenone compounds, aromatic ketone compounds, acetophenone compounds, aromatic ketal compounds, aromatic sulfonyl chloride compounds, and thioxanthone compounds.

Examples of the cationically polymerizable compound include a monofunctional cationically polymerizable compound having one cationically polymerizable functional group in the molecule, a polyfunctional cationically polymerizable compound having two or more cationically polymerizable functional groups in the molecule, and the like. Examples of the cationically polymerizable functional group include an epoxy group, an oxetanyl group, and a vinyl ether group. Examples of the cationically polymerizable compound having an epoxy group include an aliphatic epoxy compound, an alicyclic epoxy compound, and an aromatic epoxy compound. Examples of the cationically polymerizable compound having an oxetanyl group include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl] benzene, and 3-ethyl-3- (phenoxymethyl). ) Oxetane and the like. Examples of the cationically polymerizable compound having a vinyl ether group include 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, and 4-hydroxybutyl vinyl ether.
When a cationically polymerizable compound is used as the active energy ray-curable adhesive, a cationic polymerization initiator is blended. This cationic polymerization initiator generates a cationic species or Lewis acid by irradiation with active energy rays such as visible light, ultraviolet rays, and electron beams, and initiates a polymerization reaction with an epoxy group of a cationically polymerizable compound. As the cationic polymerization initiator, a photoacid generator and a photobase generator can be used.

As a preferable active energy ray-curable adhesive, for example, an adhesive having an SP value as shown below can be used.
That is, the preferable active energy ray-curable adhesive contains active energy ray-curable compounds (A), (B) and (C) as curable components. Specifically, when the total amount of the adhesive is 100% by weight, the SP value is 29.0 (MJ / m ³ ) ^{1/2 to} 32.0 (MJ / m ³ ) ^1/2. Active energy rays containing 0.0 to 15.0% by weight of type compound (A) and SP value of 18.0 (MJ / m ³ ) ^1/2 or more and less than 21.0 (MJ / m ³ ) ^1/2. Active energy containing 20.0 to 80.0% by weight of the curable compound (B) and an SP value of 21.0 (MJ / m ³ ) ^{1/2 to} 26.0 (MJ / m ³ ) ^1/2. It contains 10.0 to 80.0% by weight of the linear curable compound (C). In the present invention, the "total amount of adhesive" means the total amount including various initiators and additives in addition to each active energy ray-curable compound.

Here, the method for calculating the SP value (solubility parameter) in the present invention will be described below.
(Calculation method of solubility parameter (SP value))
In the present invention, the solubility parameter (SP value) of the active energy ray-curable compound is determined by the Fedors calculation method [“Polymer Eng. & Sci.”, Vol. 14, No. 2 ( 1974), pp. 148-154], that is, calculated by the following formula (where Δei is the evaporation energy at 25 ° C attributable to the atom or group and Δvi is the molar volume at 25 ° C). Can be sought.

Δei and Δvi in the above formula indicate constant numerical values given to i atoms and groups in the main molecule, respectively. In addition, typical examples of the numerical values of Δe and Δv given to the atom or group are shown in Table 1 below.

The active energy ray-curable compound (A) has a radically polymerizable group such as a (meth) acrylate group and has an SP value of 29.0 (MJ / m ³ ) ^{1/2 to} 32.0 (MJ / m). ³ ) ^Any compound that is 1/2 can be used without limitation. Specific examples of the active energy ray-curable compound (A) include hydroxyethyl acrylamide (SP value 29.5) and N-methylol acrylamide (SP value 31.5). In addition, in this specification, a (meth) acrylate group means an acrylate group and / or a methacrylate group.

The active energy ray-curable compound (B) has a radically polymerizable group such as a (meth) acrylate group and has an SP value of 18.0 (MJ / m ³ ) ^1/2 or more and 21.0 (MJ / m). ³ ) ^Any compound less than 1/2 can be used without limitation. Specific examples of the active energy ray-curable compound (B) include tripropylene glycol diacrylate (SP value 19.0), 1,9-nonanediol diacrylate (SP value 19.2), and tricyclodecandide. Methanol diacrylate (SP value 20.3), cyclic trimethylolpropane formal acrylate (SP value 19.1), dioxane glycol diacrylate (SP value 19.4), EO-modified diglycerin tetraacrylate (SP value 20.9) ) And so on. Commercially available products can also be preferably used as the active energy ray-curable compound (B), for example, Aronix M-220 (manufactured by Toagosei Co., Ltd., SP value 19.0), light acrylate 1,9ND-A (Kyoei Co., Ltd.). Chemical Co., Ltd., SP value 19.2), Light Acrylate DGE-4A (Kyoeisha Chemical Co., Ltd., SP value 20.9), Light Acrylate DCP-A (Kyoeisha Chemical Co., Ltd., SP value 20.3), SR-531 (Manufactured by SARTOMER, SP value 19.1), CD-536 (manufactured by SARTOMER, SP value 19.4) and the like can be mentioned.

The active energy ray-curable compound (C) has a radically polymerizable group such as a (meth) acrylate group and has an SP value of 21.0 (MJ / m ³ ) ^{1/2 to} 26.0 (MJ / m). ³ ) ^Any compound that is 1/2 can be used without limitation. Specific examples of the active energy ray-curable compound (C) include acryloyl morpholine (SP value 22.9), N-methoxymethyl acrylamide (SP value 22.9), and N-ethoxymethyl acrylamide (SP value 22. 3) and the like. As the active energy ray-curable compound (C), a commercially available product can also be preferably used. For example, ACMO (manufactured by Kojin Co., Ltd., SP value 22.9), Wasmer 2MA (manufactured by Kasano Kosan Co., Ltd., SP value 22. 9), Wasmer EMA (manufactured by Kasano Kosan Co., Ltd., SP value 22.3), Wasmer 3MA (manufactured by Kasano Kosan Co., Ltd., SP value 22.4), Aronix M-5300 (manufactured by Toagosei Co., Ltd., SP value 23.4), etc. Can be mentioned.

_{In the present invention, when the acrylic equivalent Cae of the} active energy ray-curable adhesive represented by the following formula (X) is 140 or more, the curing shrinkage when the active energy ray-curable adhesive is cured is caused. It can be suppressed. This is preferable because the adhesiveness with the polarizer is improved.
Equation (X): C _ae = 1 / Σ (W _N / N _ae )
In the formula (X), W _N is the mass fraction of the active energy ray-curable compound _{N in the adhesive, and Nae} is the acrylic equivalent of the active energy ray-curable compound N. In the present invention, the reason why the adhesive strength of the obtained adhesive layer is increased when the acrylic equivalent of the active energy ray-curable adhesive is equal to or more than a predetermined value can be estimated as follows.

The higher the acrylic equivalent of the active energy ray-curable adhesive, the more effective it is to suppress the volume shrinkage caused by the formation of covalent bonds when the adhesive is irradiated with the active energy rays and cured. As a result, the stress accumulated at the interface between the adhesive layer and the adherend can be relaxed, and as a result, the adhesive force of the adhesive layer is improved.

The acrylic equivalent C _ae is more preferably 155 or more, and even more preferably 165 or more. In the present invention, the acrylic equivalent is defined as follows.
(Acrylic equivalent) = (Molecular weight of acrylic monomer) / (Number of (meth) acryloyl groups contained in one molecule of acrylic monomer)

The active energy ray-curable adhesive is an acrylic oligomer (D) formed by polymerizing a (meth) acrylic monomer in addition to the active energy ray-curable compounds (A), (B) and (C) as curable components. ) May be contained. By containing the component (D) in the active energy ray-curable adhesive, the volume shrinkage when irradiating and curing the active energy ray on the adhesive is reduced, and the adhesive layer, the polarizer and the transparent protective film are reduced. It is possible to reduce the interfacial stress with the adherend such as. As a result, it is possible to suppress a decrease in the adhesiveness between the adhesive layer and the adherend. In order to sufficiently suppress the curing shrinkage of the cured product layer (adhesive layer), the acrylic oligomer (D) is preferably contained in the adhesive in an amount of 3.0% by weight or more, preferably 5.0% by weight or more. It is more preferable to do so. On the other hand, if the content of the acrylic oligomer (D) in the adhesive is too large, the reaction rate when the adhesive is irradiated with active energy rays is drastically reduced, which may result in poor curing. Therefore, the content of the acrylic oligomer (D) in the adhesive is preferably 25% by weight or less, and more preferably 15% by weight or less.

Since the active energy ray-curable adhesive preferably has a low viscosity in consideration of workability and uniformity during coating, the acrylic oligomer (D) formed by polymerizing the (meth) acrylic monomer is also low. It is preferably viscous. As the acrylic oligomer having a low viscosity and capable of preventing curing shrinkage of the adhesive layer, one having a weight average molecular weight (Mw) of 15,000 or less is preferable, one having a weight average molecular weight (Mw) of 15,000 or less is more preferable, and one having a weight average molecular weight (Mw) of 5,000 or less is particularly preferable. On the other hand, in order to sufficiently suppress the curing shrinkage of the cured product layer (adhesive layer), the weight average molecular weight (Mw) of the acrylic oligomer (D) is preferably 500 or more, and preferably 1000 or more. More preferably, it is 1500 or more, and particularly preferably 1500 or more. Specific examples of the (meth) acrylic monomer constituting the acrylic oligomer (D) include methyl (meth) acrylate, ethyl (meth) acrylate, N-propyl (meth) acrylate, isopropyl (meth) acrylate, and 2 -Methyl-2-nitropropyl (meth) acrylate, N-butyl (meth) acrylate, isobutyl (meth) acrylate, S-butyl (meth) acrylate, T-butyl (meth) acrylate, N-pentyl (meth) acrylate, T-pentyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth) acrylate, N-hexyl (meth) acrylate, cetyl (meth) acrylate, N-octyl (meth) acrylate, 2 (Meta) acrylic acid (1-20 carbon atoms) alkyl esters such as −ethylhexyl (meth) acrylate, 4-methyl-2-propylpentyl (meth) acrylate, N-octadecyl (meth) acrylate, and further, for example, cyclo. Alkyl (meth) acrylates (eg, cyclohexyl (meth) acrylates, cyclopentyl (meth) acrylates, etc.), aralkyl (meth) acrylates (eg, benzyl (meth) acrylates, etc.), polycyclic (meth) acrylates (eg, 2- Isobornyl (meth) acrylate, 2-norbornylmethyl (meth) acrylate, 5-norbornen-2-yl-methyl (meth) acrylate, 3-methyl-2-norbornylmethyl (meth) acrylate, etc.), hydroxyl group Contains (meth) acrylic acid esters (eg, hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2,3-dihydroxypropylmethyl-butyl (meth) methacrylate, etc.), alkoxy group or phenoxy group (containing) Meta) Acrylate esters (2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) Acrylate, phenoxyethyl (meth) acrylate, etc.), epoxy group-containing (meth) acrylic acid esters (eg, glycidyl (meth) acrylate, etc.), halogen-containing (meth) acrylic acid esters (eg, 2,2,2- Trifluoroethyl (meth) acrylate, 2,2 2-Trifluoroethyl ethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, etc.), alkylaminoalkyl ( Examples include meth) acrylates (eg, dimethylaminoethyl (meth) acrylates, etc.). These (meth) acrylates can be used alone or in combination of two or more. Specific examples of the acrylic oligomer (D) include "ARUFON" manufactured by Toagosei Co., Ltd., "Actflow" manufactured by Soken Chemical Co., Ltd., and "JONCRYL" manufactured by BASF Japan Ltd.

The active energy ray-curable adhesive preferably contains a radical polymerization initiator (E) having a hydrogen abstraction action. According to such a configuration, the adhesiveness to the adherend is remarkably improved even in a high humidity environment or a non-drying state. The reason for this is not clear, but the following causes are possible. When a radical polymerization initiator (E) having a hydrogen abstraction action is present in the active energy ray-curable adhesive, the active energy ray-curable compound polymerizes to form a base polymer constituting the adhesive layer, while forming a base polymer. Hydrogen is extracted from, for example, a methylene group of an active energy ray-curable compound, and radicals are generated. Then, the methylene group in which radicals are generated reacts with the hydroxyl group of a polarizer such as PVA, and a covalent bond is formed between the adhesive layer and the polarizer. As a result, it is presumed that the adhesiveness of the adhesive layer is remarkably improved even in a non-drying state.

In the present invention, examples of the radical polymerization initiator (E) having a hydrogen abstraction action include a thioxanthone-based radical polymerization initiator and a benzophenone-based radical polymerization initiator. Examples of the thioxanthone-based radical polymerization initiator include compounds represented by the following general formula (1).

In the formula, R ³ and R ⁴ represent -H, -CH ₂ CH ₃ , -iPr or Cl, and R ³ and R ⁴ may be the same or different.

When the compound represented by the general formula (1) is used, the adhesiveness is excellent as compared with the case where a photopolymerization initiator having high sensitivity to light of 380 nm or more is used alone. A photopolymerization initiator having high sensitivity to light of 380 nm or more will be described later. Among the compounds represented by the general formula (1), ^{diethylthioxanthone in which R 3} and R ⁴ are −CH ₂ CH ₃ is particularly preferable.

Since the photopolymerization initiator of the general formula (1) can initiate polymerization by light of a long wavelength transmitted through a transparent protective film having UV absorbing ability, the adhesive can be cured even through the UV absorbing film. Specifically, for example, even when a transparent protective film having UV absorbing ability is laminated on both sides such as triacetyl cellulose-polarizer-triacetyl cellulose, when the photopolymerization initiator of the general formula (1) is contained. , The adhesive can be cured.

The composition ratio of the radical polymerization initiator (E) having a hydrogen abstracting action in the adhesive, particularly the composition ratio of the compound represented by the general formula (1), is 0. It is preferably 1 to 10% by weight, more preferably 0.2 to 5% by weight.

In addition, it is preferable to add a polymerization initiation aid as needed. Examples of the polymerization initiator include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, and isoamyl 4-dimethylaminobenzoate. , And ethyl 4-dimethylaminobenzoate is particularly preferable. When a polymerization initiator is used, the amount of the polymerization initiator added is usually 0 to 5% by weight, preferably 0 to 4% by weight, and most preferably 0 to 3% by weight when the total amount of the adhesive is 100% by weight. ..

In addition, a known photopolymerization initiator can be used in combination if necessary. Since the transparent protective film having a UV absorbing ability does not transmit light of 380 nm or less, it is preferable to use a photopolymerization initiator having high sensitivity to light of 380 nm or more as the photopolymerization initiator. Specifically, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 , 2- (Dimethylamino) -2-[(4-Methylphenyl) Methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine Oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (Η5-2,4-cyclopentadiene-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-) 1-yl) -phenyl) titanium and the like can be mentioned.

In particular, as the photopolymerization initiator, it is preferable to further contain a compound represented by the following general formula (2) in addition to the photopolymerization initiator of the general formula (1).

In the formula, R ⁵ , R ⁶ and R ⁷ indicate -H, -CH ₃ , -CH ₂ CH ₃ , -iPr or Cl, and R ⁵ , R ⁶ and R ⁷ may be the same or different.
By using the photopolymerization initiators of the general formulas (1) and (2) in combination, the reaction becomes highly efficient due to these photosensitizing reactions, and the adhesiveness of the adhesive layer is particularly improved.

The active energy ray-curable adhesive preferably further contains an active energy ray-curable compound having an active methylene group together with a radical polymerization initiator (E) having a hydrogen abstraction action. According to such a configuration, the adhesiveness of the adhesive layer is further improved.

An active energy ray-curable compound having an active methylene group is a compound having an active double bond group such as a (meth) acrylic group at the terminal or in the molecule and having an active methylene group. Examples of the active methylene group include an acetoacetyl group, an alkoxymalonyl group, a cyanoacetyl group and the like. Specific examples of the active energy ray-curable compound having an active methylene group include 2-acetoacetoxyethyl (meth) acrylate, 2-acetoacetoxypropyl (meth) acrylate, and 2-acetacetoxy-1-methylethyl (meth). Acetacetoxyalkyl (meth) acrylates such as acrylate; 2-ethoxymalonyloxyethyl (meth) acrylate, 2-cyanoacetoxyethyl (meth) acrylate, N- (2-cyanoacetoxyethyl) acrylamide, N- (2-propionylacetoxy). Examples thereof include butyl) acrylamide, N- (4-acetoacetoxymethylbenzyl) acrylamide, and N- (2-acetoacetylaminoethyl) acrylamide. The SP value of the active energy ray-curable compound having an active methylene group is not particularly limited, and a compound having an arbitrary value can be used.

Temperature measuring means 681 and 681 are arranged on the outlet side of the coating roll 641 of the adhesive coating portion 64 of the first protective film 12 and the second protective film 13, respectively. The temperature measuring means 681 is arranged in the vicinity of the coating roll 641. The temperature measuring means 681 measures the temperature of the first protective film 12 and the second protective film 13 coated with the adhesive. Hereinafter, the first protective film 12 and the second protective film 13 may be collectively referred to as a “protective film”.
As the temperature measuring means 681, for example, a thermography camera, a radiation thermometer, or the like can be used. The thermography camera can detect infrared rays radiated from a protective film coated with an adhesive by an infrared camera, analyze an image representing the detected infrared rays, and calculate the temperature thereof. A radiation thermometer can measure the temperature of infrared rays or visible light emitted from a protective film coated with an adhesive.
The temperature measuring means 681 may measure the temperature of the protective film from the side on which the adhesive is applied, or may measure the temperature of the protective film from the side opposite to the surface on which the adhesive is applied. May be good. In the illustrated example, the temperature measuring means 681 is arranged on the surface side (adhesive layer side) on which the adhesive is applied. In this case, strictly speaking, the temperature measuring means 681 measures the temperature of the adhesive layer. However, since the adhesive layer is directly provided on one side of the protective film, the temperature of the adhesive layer and the temperature of the protective film are substantially equal, and the temperature measuring means 681 measures the temperature of the protective film. It can be said that.

Further, a cooling means 66 is provided on the transport path of the protective film (first protective film 12 and second protective film 13).
The cooling means 66 lowers the room temperature in the chamber 69 and lowers the temperature of the protective film. Examples of the cooling means 66 include a cooler that sends out cold air, a heat exchanger that circulates a refrigerant body in a pipe, and the like. The cooling means 66 may be provided in the chamber 69, and its position is not particularly limited. In the illustrated example, a cooler is used as the cooling means 66. A cooler (cooling means 66) is arranged so that the cold air from the cooler hits the protective film. In the illustrated example, the cooling means 66 is arranged between the adhesive coating portion 64 and the bonding portion 67 so as to blow cold air onto the first protective film 12 and the second protective film 13.

The bonding portion 67 attaches the protective film coated with the adhesive and the polarizer 1c.
The bonding portion 67 has nip rolls 671, 671.
The protective film (first protective film 12 and second protective film 13) provided with the adhesive layer and the polarizer 1c are inserted into the nip rolls 671 and 671 and pressed. With the nip rolls 671 and 671 on the exit side, the laminate 1d composed of the first protective film 12 / uncured adhesive layer / polarizer 1c / uncured adhesive layer / second protective film 13 is conveyed.
A temperature measuring means 682 is arranged on the outlet side of the nip roll 671 of the bonding portion 67. The temperature measuring means 682 measures the temperature of the protective film bonded to the polarizer 1c via the adhesive layer.
As the temperature measuring means 682, for example, a thermography camera, a radiation thermometer, or the like can be used. The temperature measuring means 682 may measure the temperature from the first protective film 12 side, or may measure the temperature from the second protective film 13. In the illustrated example, the temperature measuring means 682 is arranged on the first protective film 12 side.
If necessary, a cooling means may be provided on the outlet side of the nip roll 671 (not shown).

The outside of the adhesive coating portion 64 and the bonding portion 67 is surrounded by a chamber 69. In other words, in the chamber 69, an adhesive coating portion 64 including the temperature measuring means 681 and the cooling means 66 and a bonding portion 67 including the temperature measuring means 682 are arranged. Slit-shaped inlets and outlets are formed on the upstream side and the downstream side of the chamber 69 (not shown). The polarizer 1c enters the chamber 69 from the inlet on the upstream side of the chamber 69. The laminated body 1d is formed in the bonding portion 67, and the laminated body 1d is conveyed to the outside of the chamber 69 from the slit-shaped outlet of the chamber 69.
In the illustrated example, the second roll portion 62 around which the first protective film 12 is wound and the third roll portion 63 around which the second protective film 13 is wound are arranged outside the chamber 69, but the second The roll portion 62 and the third roll portion 63 may also be arranged in the chamber 69 (not shown).

When an active energy ray-curable adhesive is used as the adhesive, the curing device 7 is arranged on the downstream side of the bonding portion 67.
The curing device 7 has an irradiation device 71 that irradiates the laminated body 1d with active energy rays. If necessary, the curing device 7 may have a chamber 72. When having a chamber 72, the irradiation device 71 is arranged in the chamber 72.
The active energy ray of the irradiation device 71 is appropriately selected according to the curability of the active energy ray-curable adhesive. For example, an irradiation device 71 capable of irradiating visible light of 380 nm to 450 nm can be used.
Further, as shown in FIG. 4, the curing device 7 for irradiating the active energy rays is arranged on both side surfaces of the laminated body 1d so that the active energy rays can be irradiated from both side surfaces of the laminated body 1d. preferable.
The two irradiation devices 71 and 71 arranged on both sides may be arranged facing each other with the laminated body 1d in between, or one irradiation device 71 is arranged on the upstream side and the other irradiation device. 71 may be arranged downstream from it.
The laminate 1d that entered the chamber 72 from the slit-shaped inlet on the upstream side of the chamber 72 was discharged from the slit-shaped outlet on the downstream side of the chamber 72 to the outside of the chamber 72 after the adhesive layer was cured by the irradiation device 71. Be transported.

Since the irradiation device 71 irradiates the activation energy rays, the temperature in the vicinity of the irradiation device 71 tends to be relatively high. In this regard, since the chamber 72 surrounding the irradiation device 71 is provided, the high temperature heat of the curing device 7 is less likely to act on the bonding portion 67. Therefore, it is possible to effectively prevent the protective film from becoming too hot in the bonding portion 67 (and the adhesive coating portion 64).

[Manufacturing method of polarizer and manufacturing method of laminated polarizing film]
<Manufacturing process of polarizer>
With reference to FIG. 4, the untreated hydrophilic polymer film 1a is pulled out from the first roll portion 41, and the hydrophilic polymer film 1a is conveyed to the swelling treatment tank 4A by the conveying portion 42. The hydrophilic polymer film 1a is swollen by immersing the hydrophilic polymer film 1a in the swelling treatment liquid while transporting the hydrophilic polymer film 1a by the guide roll 42 in the swelling treatment tank 4A. The temperature of the swelling treatment liquid is not particularly limited, but is, for example, 20 ° C to 45 ° C. The time for immersing the hydrophilic polymer film 1a in the swelling treatment liquid is not particularly limited, but is, for example, 5 seconds to 300 seconds. Next, by immersing the swelled hydrophilic polymer film 1a in the dyeing solution in the dyeing tank 4B, the hydrophilic polymer film 1a is dyed with a bicolor substance. The temperature of the dyeing solution is not particularly limited, but is, for example, 20 ° C to 50 ° C. The time for immersing the hydrophilic polymer film 1a in the dyeing treatment liquid is not particularly limited, but is, for example, 5 seconds to 300 seconds. By immersing the dyed hydrophilic polymer film 1a in the cross-linking treatment liquid in the cross-linking treatment tank 4C, the bicolor substance of the hydrophilic polymer film 1a is cross-linked. The temperature of the cross-linking treatment liquid is not particularly limited, but is, for example, 25 ° C. or higher, preferably 40 ° C. to 70 ° C. The time for immersing the hydrophilic polymer film 1a in the cross-linking treatment liquid is not particularly limited, but is, for example, 5 seconds to 800 seconds.

The crosslinked hydrophilic polymer film 1a is stretched while being conveyed by a guide roll 42 in the stretching treatment liquid of the stretching treatment tank 4D. The temperature of the stretching treatment liquid is not particularly limited, but is, for example, 40 ° C. to 90 ° C. The draw ratio can be appropriately set depending on the intended purpose, but the total draw ratio is, for example, 2 to 7 times, preferably 4.5 to 6.8 times. The total draw ratio means the final draw ratio of the hydrophilic polymer film 1a. The hydrophilic polymer film 1a is washed by immersing the stretched hydrophilic polymer film 1a in the washing treatment liquid in the washing treatment tank 4E. The temperature of the cleaning treatment liquid is, for example, 5 ° C to 50 ° C. The cleaning time is, for example, 1 second to 300 seconds.
The hydrophilic polymer film after washing becomes the polarizer 1b. The obtained polarizer 1b is continuously conveyed to the drying device 5.

<Drying process>
Since the polarizer 1b obtained by the wet treatment contains a relatively large amount of water, it is dried by the drying device 5.
As the drying temperature in the drying step, the temperature of the space 53 of the chamber 52 (atmospheric temperature in the chamber 52) is set to, for example, 40 ° C. to 100 ° C., preferably 50 ° C. to 90 ° C. Further, in the case of the drying device 5 using warm air as described above, the wind speed of the warm air is set to, for example, 1 m / sec to 30 m / sec, preferably 2 m / sec to 20 m / sec.

<Adhesive coating process>
The dried long strip-shaped polarizer 1c is conveyed to the bonding portion 67 by the conveying portion 61. If necessary, an easy-adhesive composition may be applied to both sides of the dried polarizer 1c by using an adhesive-coated part (not shown) such as a gravure roll to form an easy-adhesive layer. Good. By forming the easy-adhesion layer, the adhesiveness of the protective film to the polarizer is improved. Examples of the easy-adhesion composition include a compound having a (meth) acryloyl group, an acid anhydride group-containing silane coupling agent, an acetoacetyl group-containing silane coupling agent, an isocyanul group-containing silane coupling agent, and a carboxyl group-containing polymer. Can be mentioned. The thickness of the easy-adhesion layer is not particularly limited, and is, for example, 0.1 μm to 5 μm.

On the other hand, the long strip-shaped first protective film 12 is pulled out from the second roll portion 62 and is conveyed to the bonding portion 67 by the conveying portion 61. Similarly, the long strip-shaped second protective film 13 is pulled out from the third roll portion 63 and conveyed to the bonding portion 67 by the conveying portion 61. In each transfer process, one side of the first protective film 12 and one side of the second protective film 13 are covered with an active energy ray-curable adhesive or the like with a coating roll 641 (for example, a gravure roll) of the adhesive coating portion 64. Each adhesive is applied. By applying the adhesive, an adhesive layer is formed on one side of the first protective film 12 and one side of the second protective film 13, respectively.

The thickness of the adhesive applied to the protective film is not particularly limited, but if it is too small, the adhesive strength decreases, and if it is too large, the thickness of the laminated polarizing film becomes relatively too large. From this point of view, the thickness of the adhesive coated on the protective films (first protective film 12 and second protective film 13) (coating thickness of the adhesive layer) is preferably 0.1 μm to 5 μm.

The viscosity of the adhesive at the time of coating is not particularly limited, but if it is too small or too large, coating spots of the adhesive may occur. From this point of view, the viscosity of the adhesive at 25 ° C. is preferably adjusted to 10 mPa · s to 50 mPa · s, and the viscosity at 25 ° C. is adjusted to 15 mPa · s to 45 mPa · s. More preferred. The viscosity can be measured at 25 ° C. using a viscometer.
Further, the transport speeds (line speeds) of the polarizer 1c, the first protective film 12, and the second protective film 13 at the time of coating are not particularly limited, but if they are too fast, uneven adhesion may occur and they are too slow. As a result, the production efficiency of the laminated polarizing film decreases. From this point of view, the transport speed of the protective film or the like at the time of coating is preferably 15 m / min to 40 m / min, and more preferably 20 m / min to 35 m / min.

The temperature of the protective film (protective film after coating with the adhesive) on the outlet side of the coating roll 641 is in the range of 20 ° C. to 35 ° C. As described above, the temperature of the protective film is monitored by the temperature measuring means 681 provided on the outlet side of the coating roll 641. The protective film is cooled by the cooling means 66 so that the temperature of the protective film is within the range of 20 ° C. to 35 ° C. For example, when the temperature of the protective film rises due to the measurement of the temperature measuring means 681, the control device (control program) enhances the cooling by the cooling means 66. When the temperature of the protective film is lowered by the measurement of the temperature measuring means 681, the control device lowers or stops the cooling by the cooling means 66. By controlling the cooling means 66 according to the temperature measuring means 681 in this way, the temperature of the protective film on the outlet side of the coating roll 641 is kept within the range of 20 ° C. to 35 ° C.

The temperature of the protective film on the exit side of the coating roll 641 is measured by, for example, the temperature measuring means 681 within 5 seconds after the coating roll 641 is ejected. By measuring within 5 seconds, the temperature of the protective film immediately after the adhesive is applied can be measured. By setting the position where the temperature measuring means 681 is installed in consideration of the transport speed of the protective film, the temperature of the protective film can be measured within 5 seconds after coming out of the coating roll 641.

<Laminating process>
The protective film (first protective film 12 and second protective film 13) on which the adhesive layer (uncured adhesive) is formed is conveyed to the bonding portion 67 together with the polarizer 1c. These films are made of nip roll 671 while facing the polarizer 1c and the adhesive layer formed on the first protective film 12 and the adhesive layer formed on the polarizer 1c and the second protective film 13. , 671 is inserted. By passing through the nip rolls 671 and 671, the polarizer 1c, the protective film 12 and the second protective film 13 are bonded to each other, and the protective film 12 / uncured adhesive layer / polarizer 1c / uncured adhesive layer / first A laminated body 1d made of 2 protective films 13 is obtained.
The protective film and the polarizer 1c are preferably bonded within 2 to 30 seconds after applying the adhesive to the protective film. If the adhesive is not attached to the polarizing element 1c for too long after being applied to the protective film, the adhesive may penetrate the protective film too much, and the protective film is applied to the polarizing element immediately after the adhesive is applied. When attached to 1c, the adhesive may hardly penetrate into the protective film.

The temperature of the protective film (protective film of the laminated body 1d) on the outlet side of the nip roll 671 is in the range of 20 ° C. to 35 ° C. As described above, the temperature of the protective film of the laminated body 1d is monitored by the temperature measuring means 682 provided on the outlet side of the nip roll 671. The protective film is cooled by the cooling means 66 so that the temperature of the protective film of the laminated body 1d is within the range of 20 ° C. to 35 ° C. For example, when the temperature of the protective film of the laminated body 1d rises due to the measurement of the temperature measuring means 682, the control device (control program) enhances the cooling by the cooling means 66. When the temperature of the protective film of the laminated body 1d is lowered by the measurement of the temperature measuring means 682, the control device lowers or stops the cooling by the cooling means 66. By controlling the cooling means 66 according to the temperature measuring means 682 in this way, the temperature of the protective film on the outlet side of the nip roll 671 is kept within the range of 20 ° C. to 35 ° C.
The temperature of the protective film on the exit side of the nip roll 671 is measured by, for example, the temperature measuring means 682 within 5 seconds after the nip roll 671 exits. By measuring within 5 seconds, the temperature of the protective film immediately after being bonded to the polarizer 1c can be measured. By setting the position where the temperature measuring means 682 is installed in consideration of the transport speed of the laminated body 1d, the temperature of the protective film within 5 seconds after coming out of the nip roll 671 can be measured.

Further, since the adhesive coating portion 64 and the bonding portion 67 are housed in the chamber 69, it is preferable that the temperature inside the chamber 69 is also controlled to be within the range of 20 ° C. to 35 ° C. .. By keeping the inside of the chamber 69 in the range of 20 ° C. to 35 ° C., the protective film can be applied between the outlet side of the coating roll 641 and the outlet side of the nip roll 671 (after the adhesive is applied, the protective film is attached to the polarizer. It can be kept in the temperature range of 20 ° C to 35 ° C (in a series up to the combination).

<Adhesive curing process>
When an active energy ray-curable adhesive is used, the active energy ray-curable adhesive is cured by irradiating the laminate 1d with active energy rays by the curing device 7, and the protective film 12 A laminated polarizing film 1e composed of / an adhesive layer after curing / a polarizer 1c / an adhesive layer after curing / a second protective film 13 can be obtained. The thickness of the adhesive layer made of the active energy ray-curable adhesive is substantially the same before curing (at the time of coating) and after curing.
The obtained laminated polarizing film 1e is wound around the winding roll portion 8 (see FIG. 4).

[Action and effect of the present invention]
According to the manufacturing method of the present invention, the protective film on the outer side of the coating roll in the adhesive coating process is in the range of 20 ° C. to 35 ° C., and the protective film on the outer side of the nip roll in the laminating process is 20 ° C. It is in the range of ~ 35 ° C. Preferably, the protective film between the outlet side of the coating roll and the outlet side of the nip roll is held in the range of 20 ° C. to 35 ° C. Therefore, it is possible to obtain a laminated polarizing film in which the polarizer and the protective film are well bonded via an adhesive.
In particular, by using a protective film having an easily adhesive surface such as a TAC film, the adhesive can be well compatible with or penetrate the surface of the protective film, and a laminated polarizing film having excellent correlated adhesive strength can be obtained. ..

Specifically, if the temperature of the protective film is too high after applying the adhesive to the protective film, the adhesive may impregnate the protective film too much, and the compatibility between the adhesive and the protective film may proceed too much. If the compatibility between the adhesive and the protective film progresses too much, the cohesive force of the adhesive after curing becomes insufficient, and the polarizer and the protective film cannot be firmly adhered to each other via the adhesive. Since the temperature of the protective film after the adhesive is applied is 35 ° C. or lower as in the present invention, it is possible to prevent the protective film from being excessively impregnated with the adhesive.
On the other hand, if the temperature of the protective film is too low after applying the adhesive to the protective film, it is difficult for the adhesive to impregnate the protective film, and the compatibility between the adhesive and the protective film may hardly proceed. If the adhesive and the protective film are hardly compatible with each other, a good compatible layer is not formed between the adhesive layer and the protective film, and the polarizer and the protective film cannot be firmly adhered to each other via the adhesive. When the temperature of the protective film is 20 ° C. or higher as in the present invention, the protective film is appropriately impregnated with the adhesive, and a good compatible layer is formed between the adhesive layer and the protective film. ..
Therefore, according to the production method of the present invention, it is possible to obtain a laminated polarizing film in which the polarizer and the protective film are well bonded via an adhesive.

[Use of laminated polarizing film, etc.]
The laminated polarizing film of the present invention is typically used as an optical film for a display such as a liquid crystal display device or an organic display device.
Further, the laminated polarizing film of the present invention is not limited to the case where it is used for the above-mentioned display, and can be used for applications other than the display. Applications other than displays include optical equipment, buildings, medical / food fields, and the like. When a laminated polarizing film is used in an optical device, the laminated polarizing film is processed into, for example, a polarizing lens, a transparent radio wave blocking film, or the like. When a laminated polarizing film is used for an electronic device, the laminated polarizing film is processed into, for example, a film for a light control window. When the laminated polarizing film is used in the medical / food field, the laminated polarizing film is processed into, for example, a photodegradation prevention film.

Hereinafter, Examples and Comparative Examples will be described, and the present invention will be described in more detail. However, the present invention is not limited to the following examples.

[Material used]
<TAC film>
A triacetyl cellulose film having a thickness of 60 μm (manufactured by FUJIFILM Corporation, trade name: TG60UL) was used.
<Acrylic film with easy adhesive>
A twin-screw kneader containing 100 parts by weight of the imidized MS resin and 0.62 parts by weight of a triazine-based ultraviolet absorber (trade name: T-712) described in Production Example 1 of JP-A-2010-284840. The mixture was mixed at 220 ° C. to prepare resin pellets. The obtained resin pellets were dried at 100.5 kPa at 100 ° C. for 12 hours and extruded from a T-die at a die temperature of 270 ° C. using a single-screw extruder to form a film (thickness 160 μm). Further, the molded film is stretched in an atmosphere of 150 ° C. in the transport direction (thickness 80 μm), then an easy-adhesive containing an aqueous urethane resin is applied, and then the film is transferred at 150 ° C. in a direction orthogonal to the film transport direction. The film was stretched under an atmosphere to obtain a transparent acrylic film having a thickness of 40 μm (water permeability 58 g / m ^{2 / 24h).}

<Active energy ray-curable adhesive A>
10% by weight hydroxyethyl acrylamide (manufactured by KJ Chemicals, trade name: HEAA), 30% by weight acroylmorpholin (manufactured by KJ Chemicals, trade name: ACMO), 37% by weight tripropylene glycol diacrylate (Toa) Synthetic company, trade name: ARONIX M-220), 3% by weight tetranormal butyl titanate (manufactured by Matsumoto Fine Chemical Co., Ltd., product name: TA-21), 5% by weight ω-carboxy-dicaprolactone monoacrylate (Toa Synthetic) Product name: ARONIX M-5300, 10% by weight epoxy group-modified acrylic oligomer (manufactured by Toa Synthetic Co., Ltd., product name: ARUFON UP-1190), 3% by weight 2-methyl-1- (4-methylthio) Phenyl) -2-morpholinopropan-1-one (manufactured by IGM Resins, trade name: OMNIRAD 907) and 2% by weight 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd., trade name: KAYACURE DETX-S). The mixture was mixed and stirred for 3 hours to obtain an active energy ray-curable adhesive A.
The viscosity of this active energy ray-curable adhesive A at 25 ° C. was 38 mPa · s.
<Active energy ray-curable adhesive B>
47.5% by weight acroylmorpholine (manufactured by KJ Chemicals, trade name: ACMO), 47.5% by weight of tripropylene glycol diacrylate (manufactured by Toagosei Co., Ltd., trade name: ARONIX M-220), 3 weights % 2-Methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (manufactured by IGM Resins, trade name: OMNIRAD 907) and 2% by weight 2,4-diethylthioxanthone (Nippon Kayaku) A product manufactured by KAYACURE DETX-S) was mixed and stirred for 3 hours to obtain an active energy ray-curable adhesive B.
The viscosity of this active energy ray-curable adhesive A at 25 ° C. was 16 mPa · s.
<Easy adhesive composition>
Easy adhesion composition by mixing 70% by weight of acroylmorpholin (manufactured by KJ Chemicals, trade name: ACMO), 2% by weight of 3-vinylphenylboronic acid and 28% by weight of water and stirring for 3 hours. I got something.

[Viscosity measurement method]
The viscosities of the active energy ray-curable adhesives A and B were measured at 25 ° C. using an E-type rotary viscometer (manufactured by Toki Sangyo Co., Ltd.).

[Manufacturing equipment used]
A laminated polarizing film manufacturing apparatus (manufacturing apparatus as shown in FIG. 4) having a wet processing apparatus, a drying apparatus, a laminating apparatus, and a curing apparatus was used. The manufacturing apparatus 2 (see FIG. 4) is provided with a commercially available thermography camera as the temperature measuring means 681 and 682, and further provided with a cooler as the cooling means 66.

[Example 1]
The cooler was set so that the room temperature in the chamber 69 surrounding the adhesive coating portion 64 and the bonding portion 67 was 22 ° C.
After setting the inside of the chamber 69 to the room temperature, a polarizer is produced as follows, and after drying, a first protective film and a second protective film are adhered to both sides of the polarizer to form a laminated polarizing film. Was produced.
In Example 1, a TAC film was used as the first protective film and the second protective film.

<Manufacturing process of polarizer>
Using the wet treatment apparatus of the above manufacturing apparatus, a polyvinyl alcohol film (thickness 45 μm, width 3000 mm) having an average degree of polymerization of 2400 and a saponification degree of 99.9 mol% was immersed in warm water at 30 ° C. for 60 seconds to swell. Then, the film was dyed by immersing it in an aqueous solution having a concentration of iodine / potassium iodide (weight ratio = 0.5 / 8) at a concentration of 0.3% and stretching it up to 3.5 times. Then, it was stretched in a boric acid ester aqueous solution at 65 ° C. so that the total stretching ratio was 6 times, and then washed with water to prepare a long strip-shaped polarizer.
<Polarizer drying process>
Subsequently, the polarizer was conveyed into a drying device and dried. The air velocity of the warm air of the drying device was 3 m / sec, the ambient temperature in the chamber was about 60 ° C., and the polarizer was transported at a transport speed of 25 m / min.

<Adhesive coating process, laminating process and adhesive curing process>
Subsequently, while transporting the dried polarizer to the bonding portion of the apparatus at a speed of 25 m / min, the active energy ray-curable adhesive A is coated on both sides of the polarizer with a gravure roll in a solid shape. An adhesive layer having a coating thickness of 1.0 μm was formed. At the same time, while transporting the first protective film and the second protective film (both are TAC films) at a speed of 25 m / min, active energy is applied to one side of the first protective film and one side of the second protective film by gravure rolls, respectively. The linear curable adhesive A was applied in a solid shape to form an adhesive layer having a coating thickness of 1.0 μm. The adhesive layer of the first protective film is superposed on the adhesive layer on one side of the polarizer, and the adhesive layer of the second protective film is superposed on the adhesive layer on the other side of the polarizer and passed through the nip roll of the bonding portion 67. , A laminate of the first protective film / uncured adhesive layer / polarizer / uncured adhesive layer / second protective film is obtained, and light of a wavelength of 380 nm to 450 nm is irradiated from both sides of the laminate to bond them. By curing the agent layer, a laminated polarizing film was continuously produced.

The temperature of the second protective film immediately after the adhesive was applied was measured with a thermography camera placed on the outlet side of the gravure roll. The temperature was measured at a position about 2 seconds after the second protective film came out of the gravure roll.
Further, the temperature of the second protective film of the laminated body was measured by a thermography camera arranged on the outlet side of the nip roll. The temperature was measured at a position about 2 seconds after the laminate came out of the gravure roll.
Table 2 shows the temperature of the protective film immediately after the adhesive coating and the temperature of the protective film immediately after forming the laminate (the temperature of the protective film immediately after bonding).
However, for the values in Table 2, the average value for 10 seconds was adopted from the time when the room temperature in the chamber 69 became substantially stable at the set temperature after the apparatus was operated.

[Example 2]
A laminated polarizing film was produced in the same manner as in Example 1 except that the room temperature in the chamber 69 surrounding the adhesive coating portion 64 and the bonding portion 67 was set to 29 ° C.
Table 2 shows the temperature of the protective film immediately after the adhesive coating of Example 2 and the temperature of the protective film immediately after the formation of the laminate.

[Example 3]
While transporting the dried polarizer at a speed of 25 m / min (without applying an active energy ray-curable adhesive), the easy-adhesive composition is applied to both sides in a solid manner with a gravure roll and air-dried. After forming the easy-adhesive layers having a thickness of 0.2 μm, they were transferred to the bonding portion of the apparatus, and the active energy ray-curable adhesive B was used instead of the active energy ray-curable adhesive A. A laminated polarizing film was produced in the same manner as in Example 1 except that the room temperature in the chamber 69 surrounding the adhesive coating portion 64 and the bonding portion 67 was set to 24 ° C.
Table 2 shows the temperature of the protective film immediately after the adhesive coating of Example 3 and the temperature of the protective film immediately after the formation of the laminate.

[Example 4]
While transporting the dried polarizer at a speed of 25 m / min (without applying an active energy ray-curable adhesive), the easy-adhesive composition is applied to both sides in a solid manner with a gravure roll and air-dried. After forming the easy-adhesive layers having a thickness of 0.2 μm, they were transferred to the bonding portion of the apparatus, and the active energy ray-curable adhesive B was used instead of the active energy ray-curable adhesive A. A laminated polarizing film was produced in the same manner as in Example 1 except that the room temperature in the chamber 69 surrounding the adhesive coating portion 64 and the bonding portion 67 was set to 27 ° C.
Table 2 shows the temperature of the protective film immediately after the adhesive coating of Example 4 and the temperature of the protective film immediately after the formation of the laminate.

[Example 5]
Acrylic film with easy adhesive was used for both the first protective film and the second protective film, and the room temperature in the chamber 69 surrounding the adhesive coating portion 64 and the bonding portion 67 was 22 ° C. A laminated polarizing film was produced in the same manner as in Example 1 except that it was set. An active energy ray-curable adhesive was applied to the easy-adhesive side of the acrylic film (this point also applies to Example 6 and Comparative Examples 4 and 5).
Table 2 shows the temperature of the protective film immediately after the adhesive coating of Example 5 and the temperature of the protective film immediately after the formation of the laminate.

[Example 6]
An acrylic film with an easy adhesive was used for both the first protective film and the second protective film, and the room temperature in the chamber 69 surrounding the adhesive coating portion 64 and the bonding portion 67 was 28 ° C. A laminated polarizing film was produced in the same manner as in Example 1 except that it was set.
Table 2 shows the temperature of the protective film immediately after the adhesive coating of Example 6 and the temperature of the protective film immediately after the formation of the laminate.

[Comparative Example 1]
A laminated polarizing film was produced in the same manner as in Example 1 except that the room temperature in the chamber 69 surrounding the adhesive coating portion 64 and the bonding portion 67 was set to 36 ° C.
Table 3 shows the temperature of the protective film immediately after the adhesive coating of Comparative Example 1 and the temperature of the protective film immediately after the formation of the laminate.

[Comparative Example 2]
A laminated polarizing film was produced in the same manner as in Example 1 except that the room temperature in the chamber 69 surrounding the adhesive coating portion 64 and the bonding portion 67 was set to 18 ° C.
Table 3 shows the temperature of the protective film immediately after the adhesive coating of Comparative Example 2 and the temperature of the protective film immediately after the formation of the laminate.

[Comparative Example 3]
While transporting the dried polarizer at a speed of 25 m / min (without applying an active energy ray-curable adhesive), the easy-adhesive composition is applied to both sides in a solid manner with a gravure roll and air-dried. After forming the easy-adhesive layers having a thickness of 0.2 μm, they were transferred to the bonding portion of the apparatus, and the active energy ray-curable adhesive B was used instead of the active energy ray-curable adhesive A. A laminated polarizing film was produced in the same manner as in Example 1 except that the room temperature in the chamber 69 surrounding the adhesive coating portion 64 and the bonding portion 67 was set to 37 ° C.
Table 3 shows the temperature of the protective film immediately after the adhesive coating of Comparative Example 3 and the temperature of the protective film immediately after the formation of the laminate.

[Comparative Example 4]
Acrylic film with easy adhesive was used for both the first protective film and the second protective film, and the room temperature in the chamber 69 surrounding the adhesive coating portion 64 and the bonding portion 67 was 36 ° C. A laminated polarizing film was produced in the same manner as in Example 1 except that it was set.
Table 3 shows the temperature of the protective film immediately after the adhesive coating of Comparative Example 4 and the temperature of the protective film immediately after the formation of the laminate.

[Comparative Example 5]
Acrylic film with easy adhesive was used for both the first protective film and the second protective film, and the room temperature in the chamber 69 surrounding the adhesive coating portion 64 and the bonding portion 67 was 17 ° C. A laminated polarizing film was produced in the same manner as in Example 1 except that it was set.
Table 3 shows the temperature of the protective film immediately after the adhesive coating of Comparative Example 5 and the temperature of the protective film immediately after the formation of the laminate.

[Peeling strength test]
A sample piece was prepared by cutting a laminated polarizing film into a size of 200 mm parallel to the stretching direction of the polarizer and 15 mm in the direction orthogonal to the stretching direction. A notch was made between the first protective film of the sample piece and the polarizer with a cutter knife, and the second protective film side of the laminated polarizing film was attached to a glass plate. Using a Tensilon tester (manufactured by Shimadzu Corporation, product name: AG-1 10KN), the first protective film and the polarizer were peeled off in the 90-degree direction (speed 1000 mm / min), and the initial peeling strength (N /). 15 mm) was measured. Similarly, a sample piece having a notch between the layers of the second protective film and the polarizer is prepared, the first protective film side is attached to a glass plate, and the second protective film and the polarizer are peeled off in the same manner. The initial peel strength (N / 15 mm) was measured. The results are shown in Tables 2 and 3.
“◯” in the evaluation column of Tables 2 and 3 indicates a case where the initial peel strength is 0.5 N / 15 mm or more, and “x” indicates a case where the initial peel strength is less than 0.5 N / 15 mm.

1,1e Laminated polarizing film 1c Polarizer 12,13 Protective film 2 Laminated polarizing film manufacturing equipment 4 Wet processing equipment 5 Drying equipment 6 Laminating equipment 641 Coating roll 671 Nip roll 7 Curing equipment

Claims (9)

Adhesive coating process, which applies adhesive to the protective film using a coating roll,
It has a laminating step of laminating a protective film coated with the adhesive and a polarizer through a nip roll.
The protective film on the outlet side of the coating roll in the adhesive coating step is in the range of 20 ° C to 35 ° C.
A method for producing a laminated polarizing film, wherein the protective film on the exit side of the nip roll in the laminating step is in the range of 20 ° C. to 35 ° C. The method for producing a laminated polarizing film according to claim 1, wherein the protective film is a transparent film having a surface that is easily adhered to the adhesive. The method for producing a laminated polarizing film according to claim 1 or 2, wherein the protective film is a triacetyl cellulose film. The method for producing a laminated polarizing film according to any one of claims 1 to 3, wherein the protective film is a film with a urethane-based easy adhesive. The method for producing a laminated polarizing film according to claim 1 or 2, wherein the protective film is an acrylic film with a urethane-based easy adhesive. The method for producing a laminated polarizing film according to any one of claims 1 to 5, wherein the adhesive is an active energy ray-curable adhesive. The method for producing a laminated polarizing film according to any one of claims 1 to 6, wherein the adhesive is applied to the protective film to a thickness of 0.1 μm to 5 μm. The laminated polarizing film according to any one of claims 1 to 7, wherein the polarizing element is attached to the protective film within 2 to 30 seconds after the adhesive is applied to the protective film. Production method. The laminated polarizing film according to any one of claims 1 to 8, wherein the protective film between the outlet side of the coating roll and the outlet side of the nip roll is held in the range of 20 ° C. to 35 ° C. Production method.

Images