WO2021084751A1

WO2021084751A1 - Layered body, layered body manufacturing method, and polarizing plate manufacturing method

Info

Publication number: WO2021084751A1
Application number: PCT/JP2019/043116
Authority: WO
Inventors: 西村　浩; 奈々恵藤枝; 田坂　公志; 崇南條
Original assignee: コニカミノルタ株式会社
Priority date: 2019-11-01
Filing date: 2019-11-01
Publication date: 2021-05-06
Also published as: JPWO2021084751A1; TWI840609B; KR20220058951A; JP7388443B2; TW202118637A

Abstract

This layered body includes: a support body; and a light-transmitting resin layer disposed on the surface of the support body so as to be removeable therefrom. The light-transmitting resin layer contains: a (meth) acrylic resin having a weight-average molecular weight of at least 1,000,000; and rubber particles. The layered body has a tensile elastic modulus, at 25℃, of 2.0-6.0GPa.

Description

Laminated body, manufacturing method of laminated body, manufacturing method of polarizing plate

The present invention relates to a laminate, a method for producing a laminate, and a method for producing a polarizing plate.

A polarizing plate used in a display device such as a liquid crystal display device or an organic EL display device includes a polarizing element and a protective film for protecting the polarizing element. In recent years, display devices used for mobile applications such as smartphones and tablet terminals have been required to be thinned, and polarizing plates and protective films, which are constituent members thereof, are also required to be thinned.

The protective film is usually manufactured by a method (solution casting method) in which a resin is dissolved in a solvent, a solution called a doping is cast, and then dried. Then, the obtained protective film is bonded to a polarizing element to manufacture a polarizing plate.

On the other hand, as a method for producing a polarizing plate having a thinner protective film, a peelable laminated film (laminated body) having a base film (support) and a translucent film (translucent resin layer) is used. A method has been proposed in which a translucent film is attached to a polarizer and a base film is peeled off to manufacture a polarizing plate (see Patent Documents 1 to 3).

JP-A-2018-41028 JP-A-2018-45220 Japanese Unexamined Patent Publication No. 2013-134336

By the way, in the laminate as shown in Patent Documents 1 to 3, a paint for a translucent resin layer is applied on a strip-shaped support, or a material for a support and a material for a translucent resin layer are mixed. Manufactured by co-spreading. Then, the obtained laminate is transported or stored in a rolled state, and then unwound from the roll and used when manufacturing a polarizing plate.

However, there is a problem that deformation (rolling deformation) of the roll body is likely to occur during transportation or storage of the roll body of the laminated body, and the deformation is easily transferred to the surface of the translucent resin layer. Such deformation of the roll body is more likely to occur as the length and width of the laminated body are longer. Further, the same problem has occurred while the rolled body of the obtained polarizing plate is transported or stored.

Further, since the thickness of the translucent resin layer is as thin as 10 μm or less, it is also required that the translucent resin layer does not break when being conveyed by a roll or the like while applying tension to the laminate.

The present invention has been made in view of the above circumstances, and is suitable for winding deformation when the laminated body or the polarizing plate is wound in a roll shape and stored for a certain period of time without causing breakage during transportation of the laminated body. It is an object of the present invention to provide a laminate capable of suppressing the accompanying surface defects, a method for producing the same, and a method for producing a polarizing plate using the laminate.

The above problem can be solved by the following configuration.

The laminate of the present invention is a laminate having a support and a translucent resin layer removably arranged on the surface thereof, and the translucent resin layer has a weight average molecular weight of 1 million or more. It contains a (meth) acrylic resin and rubber particles, and the tensile elastic modulus of the laminate at 25 ° C. is 2.0 to 6.0 GPa.

The method for producing a laminate of the present invention includes a step of obtaining a solution for a translucent resin layer containing a (meth) acrylic resin having a weight average molecular weight of 1 million or more, rubber particles, and a solvent, and the translucency. The step of applying the resin layer solution to the surface of the support and the solvent being removed from the applied translucent resin layer solution to form a translucent resin layer to form a translucent resin layer to have tensile elasticity at 25 ° C. It has a step of obtaining a laminate having a ratio of 2.0 to 6.0 GPa.

The method for producing a polarizing plate of the present invention includes a step of adhering the translucent resin layer of the laminate of the present invention to the surface of a polarizing element and a surface of the translucent resin layer on the opposite side of the polarizing element. It has a step of peeling off the support arranged in.

According to the present invention, a laminated body capable of suppressing breakage during transportation of the laminated body and suppressing surface defects due to winding deformation when the laminated body or the polarizing plate is stored in a rolled state for a certain period of time. And a method for producing the same, and a method for producing a polarizing plate using the laminated body.

FIG. 1 is a cross-sectional view showing a laminated body according to an embodiment of the present invention. FIG. 2 is a schematic view of a manufacturing apparatus for carrying out the method for manufacturing a laminated body according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing a polarizing plate according to an embodiment of the present invention.

As a result of diligent studies, the present inventors have made it possible to appropriately increase the tensile elastic modulus of the entire laminate and to include a high-molecular-weight (meth) acrylic resin and rubber particles in the translucent resin layer. It has been found that the deformation of the translucent resin layer during transportation can be suppressed while the deformation of the translucent resin layer when wound around the roll body can be suppressed.

The reason for this is not clear, but it is presumed as follows. For example, by adjusting the monomer composition of the (meth) acrylic resin contained in the translucent resin layer to appropriately increase the tensile elastic modulus of the laminated body, the laminated body becomes moderately hard, so that the roll body is deformed. It can be less likely to occur.

On the other hand, if the tensile elastic modulus of the laminated body is made too high, the translucent resin layer is likely to break when the laminated body is transported under tension. On the other hand, by setting the (meth) acrylic resin contained in the translucent resin layer to a high molecular weight, not only the toughness can be enhanced, but also the rubber particles are further contained in the translucent resin layer. It can be made easier to flexibly follow the tension. As a result, when the laminated body is transported, it is possible to prevent the translucent resin layer from breaking due to the transport tension, and it is possible to improve the transport stability.
Further, since the translucent resin layer contains rubber particles, even if the roll body of the laminated body is deformed, the restoring force of the rubber particles makes it easy to return the translucent resin layer to its original shape. , Deformation can be less likely to remain. Similarly, in the roll body of the polarizing plate, the roll body is less likely to be deformed, and the translucent resin layer can be easily returned to the original shape.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1. 1. Laminated Body FIG. 1 is a cross-sectional view showing a laminated body according to an embodiment of the present invention. As shown in FIG. 1, the laminate 100 according to the present embodiment has a support 110 and a translucent resin layer 120 removably arranged on the surface thereof.

The tensile elastic modulus G of the laminated body is preferably 2.0 to 6.0 GPa. When the tensile elastic modulus G of the laminated body is 2.0 GPa or more, winding deformation can be less likely to occur while the roll body of the laminated body and the roll body of the polarizing plate obtained by using the roll body are stored. When the tensile elastic modulus G of the laminated body is 6.0 GPa or less, the translucent resin layer is less likely to be broken when the laminated body is conveyed while applying the conveying tension, and the conveying stability can be improved. From the same viewpoint, the tensile elastic modulus G of the laminated body is more preferably 3.5 to 5.5 GPa.

The tensile elastic modulus G of the laminated body can be measured by the following procedure.
1) The laminate is cut into 1 cm × 10 cm and used as a sample. This sample is humidity controlled for 24 hours in an environment of 25 ° C. and 60% RHS.
2) Next, the tensile elastic modulus of the obtained sample is measured by the tensile test method described in JIS K7127: 1999 (ISO 527-3: 1995). Specifically, the sample is set in a tensile test device (for example, Tencilon manufactured by Orientec Co., Ltd.), a tensile test is performed under the conditions of a distance between chucks of 50.0 mm and a tensile speed of 50 mm / min, and the tensile elastic modulus is measured. The measurement is performed at 25 ° C. and 60% RH.

The tensile elastic modulus G of the laminated body can be adjusted by the tensile elastic modulus G1 of the support and the tensile elastic modulus G2 of the translucent resin layer. The tensile elastic modulus G1 of the support can be adjusted by the material of the support, heat treatment, and stretching treatment. The tensile elastic modulus G2 of the translucent resin layer can be adjusted by the composition of the translucent resin layer (particularly, the monomer composition and the weight average molecular weight of the (meth) acrylic resin).

1-1. Support The support may include a resin film, although it is not particularly limited as long as it can support the translucent resin layer.

Examples of resin films include polyester resin films (eg, polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), etc.). , Cycloolefin resin film (COP), acrylic film, cellulose resin film (for example, triacetyl cellulose film (TAC), etc.). Among them, PET film, triacetyl cellulose film (TAC), and cycloolefin resin film are preferable from the viewpoint of versatility and high tensile elastic modulus.

The resin film may be heat-relaxed or stretched.

In the heat relaxation, the crystallinity and the orientation can be lowered by heat-treating the support, so that the tensile elastic modulus G1 of the resin film and the support can be lowered. The heat relaxation temperature is not particularly limited, but can be set to (Tg + 60) to (Tg + 180) ° C., where Tg is the glass transition temperature of the resin constituting the resin film. Thermal relaxation may be performed before the release layer is formed or after the release layer is formed.

In the stretching treatment, the resin film is stretched to increase the orientation of the resin molecules, whereby the tensile elastic modulus G1 of the resin film and the support can be increased. The stretching treatment may be performed, for example, in the uniaxial direction of the support or in the biaxial direction. The stretching treatment can be carried out under any conditions, for example, at a stretching ratio of about 120 to 900%. The draw ratio is a value obtained by multiplying the draw ratio in each direction. Whether or not the resin film is stretched (whether or not it is a stretched film) can be confirmed by, for example, whether or not there is an in-plane slow layer axis (an axis extending in the direction of maximizing the refractive index).

The support preferably further has a release layer provided on the surface of the resin film. The release layer can facilitate the peeling of the translucent resin layer from the support when the polarizing plate is produced.

The release layer may contain a known release agent or release agent, and is not particularly limited. Examples of the release agent contained in the release layer include a silicone-based release agent and a non-silicone-based release agent.

Examples of silicone-based release agents include known silicone-based resins. Examples of non-silicone release agents include long-chain alkyl pendant-type polymers obtained by reacting a long-chain alkyl isocyanate with a polyvinyl alcohol or an ethylene-vinyl alcohol copolymer, and olefin resins (for example, copolymerized polyethylene, cyclic polyolefin, etc.). Polymethylpentene), polyallylate resins (eg, copolymers of aromatic dicarboxylic acid components and divalent phenol components), fluororesins (eg, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride) (PVF), PFA (copolymer of tetrafluoroethylene and perfluoroalkoxyethylene), FEP (copolymer of tetrafluoroethylene and hexafluoropropylene), ETFE (copolymer of tetrafluoroethylene and ethylene)) Etc. are included.

The release layer may further contain an additive if necessary. Examples of additives include fillers, lubricants (waxes, fatty acid esters, fatty acid amides, etc.), stabilizers (antioxidants, heat stabilizers, light stabilizers, etc.), flame retardants, viscosity modifiers, thickeners, etc. Includes defoamers and UV absorbers.

The thickness of the release layer may be as long as it can exhibit the desired peelability, and is not particularly limited, but is preferably 0.1 to 1.0 μm, for example.

(Tensile modulus G1)
The tensile elastic modulus G1 of the support may be set so that the tensile elastic modulus G of the laminated body satisfies the above range, and is not particularly limited, but may be, for example, 2.0 to 6.0 GPa. When the tensile elastic modulus G1 of the support is 2.0 GPa or more, winding deformation can be less likely to occur while the roll body of the laminated body or the roll body of the polarizing plate is stored. When the tensile elastic modulus G1 of the support is 6.0 GPa or less, the support and the laminate are less likely to be broken when the laminate is transported while applying tension, and the transport stability can be improved. The tensile elastic modulus G1 of the support can be measured by performing the tensile test described in JIS K7127: 1999 (ISO 527-3: 1995) in the same manner as described above. If the support has anisotropy, prepare two types of samples, one in the orientation direction (in-plane slow phase axial direction, for example, the TD direction) and the other in the direction orthogonal to it (for example, the MD direction), measure each of them, and measure them. Take the average value.

(Thickness)
The thickness of the support is not particularly limited, but is preferably, for example, 10 to 100 μm, and more preferably 25 to 50 μm.

1-2. Translucent resin layer The translucent resin layer is arranged on the support. The translucent resin layer is peeled off from the support and then bonded to a polarizing element to form a polarizing plate, and can function as an optical film such as a protective film (including a retardation film).

The translucent resin layer contains a high molecular weight (meth) acrylic resin and rubber particles.

1-2-1. (Meta) Acrylic Resin The weight average molecular weight (Mw) of the (meth) acrylic resin is preferably 1 million or more. When the weight average molecular weight of the (meth) acrylic resin is 1 million or more, the toughness of the obtained translucent resin layer can be enhanced. As a result, even if the tensile elastic modulus of the laminated body is high, it is possible to make it difficult for the translucent resin layer to break due to the transport tension. Further, since the tensile elastic modulus of the translucent resin layer can be increased, winding deformation can be less likely to occur. From the same viewpoint, the weight average molecular weight of the (meth) acrylic resin is more preferably 1.5 million to 3 million.

The weight average molecular weight (Mw) of the (meth) acrylic resin can be measured by gel permeation chromatography (GPC) in terms of polystyrene. Specifically, the measurement can be performed using a Tosoh HLC8220GPC) and a column (Tosoh TSK-GEL G6000HXL-G5000HXL-G5000HXL-G4000HXL-G3000HXL series). The measurement conditions may be the same as in the examples described later.

The (meth) acrylic resin having a weight average molecular weight satisfying the above range contains at least a structural unit (U1) derived from methyl methacrylate. Above all, from the viewpoint of increasing the tensile elastic modulus G2 of the translucent resin layer to prevent the roll body from being rolled and deformed when stored in the roll body, the (meth) acrylic resin has a structure derived from phenylmaleimide. It is preferable to further contain the unit (U2), and from the viewpoint of improving the brittleness due to the inclusion of the structural unit (U2), the structural unit (U3) derived from the structural unit (U3) derived from the acrylic acid alkyl ester is used. It is more preferable to further include it.

That is, the (meth) acrylic resin contains a structural unit (U1) derived from methyl methacrylate, a structural unit (U2) derived from phenylmaleimide, and a structural unit (U3) derived from an acrylic acid alkyl ester. Is preferable.

The content of the structural unit (U1) derived from methyl methacrylate is preferably 50 to 95% by mass, preferably 70 to 90% by mass, based on all the structural units constituting the (meth) acrylic resin. Is more preferable.

Since the structural unit (U2) derived from phenylmaleimide has a relatively rigid structure, the tensile elastic modulus G2 of the translucent resin layer can be increased. Further, since the structural unit (U2) derived from phenylmaleimide has a relatively bulky structure, it may have microscopic voids in the resin matrix that can move the rubber particles. Therefore, the rubber particles can be made of a translucent resin. It can be easily distributed unevenly on the surface layer of the layer.

The content of the structural unit (U2) derived from phenylmaleimide is preferably 1 to 25% by mass with respect to all the structural units constituting the (meth) acrylic resin. When the content of the structural unit (U2) derived from phenylmaleimide is 1% by mass or more, the tensile elastic modulus G2 of the translucent resin layer is likely to be increased, and when it is 25% by mass or less, the translucent resin layer Brittleness is not overly impaired. From the above viewpoint, the content of the structural unit (U2) derived from phenylmaleimide is more preferably 7 to 15% by mass.

Since the structural unit (U3) derived from the acrylic acid alkyl ester can impart appropriate flexibility to the resin, for example, the brittleness due to containing the structural unit (U2) derived from phenylmaleimide can be improved.

The acrylic acid alkyl ester is preferably an acrylic acid alkyl ester having an alkyl portion having 1 to 7 carbon atoms, preferably 1 to 5 carbon atoms. Examples of acrylic acid alkyl esters include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate and the like.

The content of the structural unit (U3) derived from the acrylic acid alkyl ester is preferably 1 to 25% by mass with respect to all the structural units constituting the (meth) acrylic resin. When the content of the structural unit (U3) derived from the acrylic acid alkyl ester is 1% by mass or more, appropriate flexibility can be imparted to the (meth) acrylic resin, so that the translucent resin layer does not become too brittle. , Hard to break. When the content of the structural unit (U3) derived from the acrylic acid alkyl ester is 25% by mass or less, the Tg of the (meth) acrylic resin does not decrease too much, so that the heat resistance and tensile elastic modulus of the translucent resin layer do not decrease too much. G2 is unlikely to decrease excessively. From the above viewpoint, the content of the structural unit derived from the acrylic acid alkyl ester is more preferably 5 to 15% by mass.

The ratio of the structural unit (U2) derived from phenylmaleimide to the total amount of the structural unit (U2) derived from phenylmaleimide and the structural unit (U3) derived from the acrylic acid alkyl ester shall be 20 to 70% by mass. Is preferable. When the ratio is 20% by mass or more, the tensile elastic modulus G2 of the translucent resin layer is likely to be increased, and when it is 70% by mass or less, the translucent resin layer is not too brittle.

The glass transition temperature (Tg) of the (meth) acrylic resin is preferably 100 ° C. or higher, more preferably 120 to 150 ° C. When the Tg of the (meth) acrylic resin is within the above range, the heat resistance of the translucent resin layer can be easily increased. In order to adjust the Tg of the (meth) acrylic resin, for example, it is preferable to adjust the content of the structural unit (U2) derived from phenylmaleimide and the structural unit (U3) derived from the acrylic acid alkyl ester.

The content of the (meth) acrylic resin is preferably 50% by mass or more, more preferably 60% by mass or more, and further preferably 70% by mass or more with respect to the translucent resin layer. ..

1-2-2. Rubber particles The rubber particles may have a function of imparting toughness (suppleness) to the translucent resin layer.

Rubber particles are particles containing a rubber-like polymer. The rubber-like polymer is a soft crosslinked polymer having a glass transition temperature of 20 ° C. or lower. Examples of such cross-linked polymers include butadiene-based cross-linked polymers, (meth) acrylic-based cross-linked polymers, and organosiloxane-based cross-linked polymers. Among them, the (meth) acrylic crosslinked polymer is preferable, and the acrylic crosslinked polymer (acrylic) is preferable from the viewpoint that the difference in refractive index from the (meth) acrylic resin is small and the transparency of the translucent resin layer is not easily impaired. Rubber-like polymer) is more preferable.

That is, the rubber particles are preferably particles containing the acrylic rubber-like polymer (a).

About acrylic rubber-like polymer (a):
The acrylic rubber-like polymer (a) is a crosslinked polymer containing a structural unit derived from an acrylic acid ester as a main component. Including as a main component means that the content of structural units derived from acrylic acid ester is in the range described later. The acrylic rubber-like polymer (a) has a structural unit derived from an acrylic acid ester, a structural unit derived from another monomer copolymerizable therewith, and two or more radically polymerizable groups in one molecule ( It is preferably a crosslinked polymer containing a structural unit derived from a polyfunctional monomer having a non-conjugated reactive double bond).

Acrylic acid esters include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, sec-butyl acrylate, isobutyl acrylate, benzyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, acrylic. An acrylic acid alkyl ester having 1 to 12 carbon atoms of an alkyl group such as n-octyl acid is preferable. The acrylic acid ester may be one kind or two or more kinds.

The content of the structural unit derived from the acrylic acid ester is preferably 40 to 90% by mass, preferably 50 to 80% by mass, based on all the structural units constituting the acrylic rubber-like polymer (a1). Is more preferable. When the content of the acrylic acid ester is within the above range, it is easy to impart sufficient toughness to the protective film.

The other copolymerizable monomer is a monomer copolymerizable with the acrylic acid ester other than the polyfunctional monomer. That is, the copolymerizable monomer does not have two or more radically polymerizable groups. Examples of copolymerizable monomers include methacrylic acid esters such as methyl methacrylate; styrenes such as styrene and methylstyrene; (meth) acrylonitriles; (meth) acrylamides; (meth) acrylic acid. .. Among them, the other copolymerizable monomer preferably contains styrenes. The other copolymerizable monomer may be one kind or two or more kinds.

The content of the structural unit derived from the other copolymerizable monomer is preferably 5 to 55% by mass with respect to all the structural units constituting the acrylic rubber-like polymer (a), and is preferably 10 to 55% by mass. It is more preferably 45% by mass.

Examples of polyfunctional monomers include allyl (meth) acrylate, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate, diallyl malate, divinyl adipate, divinylbenzene, ethylene glycol di (meth) acrylate, and diethylene glycol (diethylene glycol). Includes meth) acrylates, triethylene glycol di (meth) acrylates, trimethylrol propanetri (meth) acrylates, tetromethylol methanetetra (meth) acrylates, dipropylene glycol di (meth) acrylates, polyethylene glycol di (meth) acrylates. ..

The content of the structural unit derived from the polyfunctional monomer is preferably 0.05 to 10% by mass, preferably 0.1% by mass, based on the total structural units constituting the acrylic rubber-like polymer (a). More preferably, it is ~ 5% by mass. When the content of the polyfunctional monomer is 0.05% by mass or more, the degree of cross-linking of the obtained acrylic rubber-like polymer (a) can be easily increased, so that the hardness and rigidity of the obtained translucent resin layer can be easily increased. Is not too impaired, and if it is 10% by mass or less, the toughness of the translucent resin layer is not easily impaired.

The monomer composition constituting the acrylic rubber-like polymer (a) can be measured by, for example, the peak area ratio detected by thermal decomposition GC-MS.

The glass transition temperature (Tg) of the rubber-like polymer is preferably 0 ° C. or lower, more preferably −10 ° C. or lower. When the glass transition temperature (Tg) of the rubber-like polymer is 0 ° C. or lower, appropriate toughness can be imparted to the film. The glass transition temperature (Tg) of the rubber-like polymer is measured by the same method as described above.

The glass transition temperature (Tg) of the rubber-like polymer can be adjusted by the composition of the rubber-like polymer. For example, in order to lower the glass transition temperature (Tg) of the acrylic rubber-like polymer (a), an acrylic acid ester having 4 or more carbon atoms in the alkyl group in the acrylic rubber-like polymer (a) / It is preferable to increase the mass ratio of other copolymerizable monomers (for example, 3 or more, preferably 4 to 10).

The particles containing the acrylic rubber-like polymer (a) are the particles made of the acrylic rubber-like polymer (a) or the hard layer made of the hard crosslinked polymer (c) having a glass transition temperature of 20 ° C. or higher. , Particles having a soft layer made of an acrylic rubber-like polymer (a) arranged around the acrylic polymer (a) may be used (these are also referred to as “epolymers”); the acrylic rubber-like polymer (a). It may be a particle made of an acrylic graft copolymer obtained by polymerizing a mixture of monomers such as a methacrylate ester in the presence of at least one step or more. The particles made of the acrylic graft copolymer may be core-shell type particles having a core portion containing the acrylic rubber-like polymer (a) and a shell portion covering the core portion.

About core-shell type rubber particles containing acrylic rubber-like polymer:
(Core part)
The core portion contains an acrylic rubber-like polymer (a), and may further contain a hard crosslinked polymer (c), if necessary. That is, the core portion may have a soft layer made of an acrylic rubber-like polymer and a hard layer made of a hard crosslinked polymer (c) arranged inside the soft layer.

The crosslinked polymer (c) can be a crosslinked polymer containing a methacrylic acid ester as a main component. That is, the crosslinked polymer (c) includes a structural unit derived from a methacrylic acid alkyl ester, a structural unit derived from another monomer copolymerizable therewith, and a structural unit derived from a polyfunctional monomer. It is preferably a crosslinked polymer containing.

The alkyl methacrylic acid ester may be the alkyl methacrylic acid ester described above; the other copolymerizable monomer may be the styrenes or acrylic acid ester described above; the polyfunctional monomer may be. Examples thereof include those similar to those mentioned above as the polyfunctional monomer.

The content of the structural unit derived from the methacrylic acid alkyl ester can be 40 to 100% by mass with respect to all the structural units constituting the crosslinked polymer (c). The content of the structural unit derived from the other copolymerizable monomer can be 60 to 0% by mass with respect to the total structural unit constituting the other crosslinked polymer (c). The content of the structural unit derived from the polyfunctional monomer can be 0.01 to 10% by mass with respect to all the structural units constituting the other crosslinked polymer.

(Shell part)
The shell portion contains a methacrylic polymer (b) (another polymer) graft-bonded to the acrylic rubber-like polymer (a) and containing a structural unit derived from a methacrylic acid ester as a main component. Including as a main component means that the content of structural units derived from methacrylic acid ester is in the range described later.

The methacrylic acid ester constituting the methacrylic acid polymer (b) is preferably an alkyl methacrylate having 1 to 12 carbon atoms of an alkyl group such as methyl methacrylate. The methacrylic acid ester may be one kind or two or more kinds.

The content of the methacrylic acid ester is preferably 50% by mass or more with respect to all the structural units constituting the methacrylic acid polymer (b). When the content of the methacrylic acid ester is 50% by mass or more, compatibility with a methacrylic resin containing a structural unit derived from methyl methacrylate as a main component can be easily obtained. From the above viewpoint, the content of the methacrylic acid ester is more preferably 70% by mass or more with respect to all the structural units constituting the methacrylic polymer (b).

The methacrylic polymer (b) may further contain structural units derived from other monomers copolymerizable with the methacrylic acid ester. Examples of other copolymerizable monomers are acrylic acid esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate; benzyl (meth) acrylate, dicyclopentanyl (meth) acrylate, A (meth) acrylic monomer having an alicyclic, heterocyclic or aromatic ring such as phenoxyethyl (meth) acrylate (ring-containing (meth) acrylic monomer) is included.

The content of the structural unit derived from the copolymerizable monomer is preferably 50% by mass or less, preferably 30% by mass or less, based on all the structural units constituting the methacrylic polymer (b). Is more preferable.

The ratio of the graft component in the rubber particles (graft ratio) is preferably 10 to 250% by mass, more preferably 15 to 150% by mass. When the graft ratio is above a certain level, the proportion of the graft component, that is, the methacrylic polymer (b) containing the structural unit derived from the methacrylic acid ester as the main component is moderately large, so that the rubber particles and the methacrylic resin are separated from each other. It is easy to improve compatibility and it is more difficult to agglomerate rubber particles. In addition, the rigidity of the film is not easily impaired. When the graft ratio is below a certain level, the proportion of the acrylic rubber-like polymer (a) does not become too small, so that the toughness and brittleness improving effect of the film are not easily impaired.

The graft ratio is measured by the following method.
1) Dissolve 2 g of core-shell type particles in 50 ml of methyl ethyl ketone and centrifuge at a rotation speed of 30,000 rpm and a temperature of 12 ° C. for 1 hour using a centrifuge (manufactured by Hitachi Koki Co., Ltd., CP60E) to remove insoluble matter. Separate into the lysate (centrifugal separation work is set 3 times in total).
2) The graft ratio is calculated by applying the weight of the obtained insoluble matter to the following formula.
Graft ratio (mass%) = [{(mass of methyl ethyl ketone insoluble matter)-(mass of acrylic rubber-like polymer (a))} / (mass of acrylic rubber-like polymer (a))] × 100

The shape of the rubber particles is not particularly limited, but it is preferable that the shape is close to a true sphere. The shape close to a spherical shape means a shape in which the aspect ratio of the rubber particles is in the range of about 1 to 2 when observing the cross section or the surface of the translucent resin layer. As described above, when the rubber particles have a spherical shape, the laminated body is more resistant to deformation due to contact with the roll during transportation and internal stress during winding, and resistance to deformation is more likely to be obtained.

The average particle size of the rubber particles is preferably 100 to 400 nm. When the average particle size of the rubber particles is 100 nm or more, sufficient toughness and stress relaxation property are easily imparted to the translucent resin layer, and when it is 400 nm or less, the transparency of the translucent resin layer is not easily impaired. From the same viewpoint, the average particle size of the rubber particles is more preferably 150 to 300 nm.

The average particle size of the rubber particles can be calculated by the following method.
The average particle size of the rubber particles can be measured as an average value of the equivalent circle diameters of 100 particles obtained by SEM or TEM photography of the surface or section of the laminate. The equivalent circle diameter can be obtained by converting the projected area of the particles obtained by photographing into the diameter of a circle having the same area. At this time, the rubber particles observed by SEM observation and / or TEM observation at a magnification of 5000 times are used for calculating the average particle size.

The content of the rubber particles is not particularly limited, but is preferably 5 to 50% by mass, more preferably 5 to 40% by mass, based on the (meth) acrylic resin contained in the translucent resin layer. It is preferably 7 to 30% by mass, and more preferably 7 to 30% by mass.

(Distribution of rubber particles)
The rubber particles may be uniformly dispersed in the thickness direction of the translucent resin layer, or may be unevenly distributed. Specifically, in the cross section along the thickness direction of the translucent resin layer, the region A is 20% or less of the thickness of the translucent resin layer from the surface opposite to the support of the translucent resin layer. The region B is 20% or less of the thickness of the translucent resin layer from the surface of the translucent resin layer on the support side, the area ratio of the rubber particles in the region A per unit area is _RA , and the rubber in the region B. when the area ratio per unit area of the particles was _{_{R _B,} R} a / _{R B} may be a 1.0-1.1.

Above all, from the viewpoint of making it difficult to generate stress when the laminate is curled and improving the adhesiveness with the polarizer, the rubber particles are the surface layer portion of the translucent resin layer (the surface layer opposite to the support). It is preferable that the parts are unevenly distributed. _{Specifically, the RA} / R _B of the translucent resin layer is more preferably 1.05 to 1.1. When _RA / R _B is 1.05 or more, the rubber particles are unevenly distributed on the surface layer portion of the translucent resin layer. As a result, the flexibility and toughness of the surface layer of the translucent resin layer can be increased, so that not only is it easy to highly suppress breakage during transportation, but also winding deformation occurs during storage of the rolled body of the laminated body. Even if the deformation is transferred to the translucent resin layer, it can easily return to the original shape. Further, when _RA / R _B is 1.1 or less, the difference in toughness between the surface layer portion and the inside of the translucent resin layer does not become too large, so that cracks are unlikely to occur due to the stress difference during transportation or the like.

_{The area ratio RA} per unit area of the rubber particles in the region A is represented by the following formula (1).
Equation (1): Area ratio _RA (%) = total area of rubber particles in region A / area of region A x 100
Area ratio R _B per unit area of the rubber particles in the area B is similarly defined.

R _{A /} R _B of the translucent resin layer can be measured by the following method.
1) The translucent resin layer is cut with a microtome, and the cut surface perpendicular to the surface of the translucent resin layer is observed by TEM. The observation conditions may be acceleration voltage (electron energy irradiating the sample): 30 kV, working distance (distance between the lens and the sample): 8.6 mm × magnification: 3.00 k. The observation region is a region including the entire thickness direction of the translucent resin layer.
2) The obtained TEM image is subjected to an opening process after removing the brightness gradient using image processing software of NiVision (manufactured by National Instruments), and the contrast difference between the bulk and the rubber particles is detected. Thereby, the distribution state of the rubber particles is specified.
3) In the image after image processing obtained in 2) above, the area ratio _RA per unit area of the rubber particles in the region A and the unit area of the rubber particles in the region B in the thickness direction of the translucent resin layer. calculating the area ratio R _B, respectively.
_{4) R A} / R _B is calculated from the result obtained in 3) above.

The method of unevenly distributing the rubber particles is not particularly limited, but can be adjusted depending on the type of solvent of the translucent resin layer solution, the drying conditions of the coating film (drying temperature and atmospheric solvent concentration), the composition of the (meth) acrylic resin, and the like. .. In order to facilitate uneven distribution of the rubber particles on the surface layer portion (region A) of the translucent resin layer, a solvent having a high affinity with the rubber particles (for example, ketones such as acetone) is used as the solvent as described later. It is preferable to use it, it is preferable to raise the drying temperature, and it is preferable to lower the solvent concentration in the atmosphere. Further, the (meth) acrylic resin containing a moderately large amount of the structural unit (U2) derived from phenylmaleimide has many microscopic voids and easily diffuses and moves the rubber particles. Therefore, the structural unit derived from the phenylmaleimide. By appropriately increasing the content of (U2), it is possible to make it easier for the rubber particles to be unevenly distributed.

1-2-3. Other components The translucent resin layer may further contain components other than the above, if necessary. Examples of other components include matting agents (fine particles), ultraviolet absorbers and the like.

The matting agent can be added from the viewpoint of imparting slipperiness to the film. Examples of the matting agent include inorganic fine particles such as silica particles and organic fine particles having a glass transition temperature of 80 ° C. or higher.

Examples of UV absorbers include benzotriazole-based UV absorbers, benzophenone-based UV absorbers, and triazine-based UV absorbers.

1-2-4. Physical properties (tensile elastic modulus G2)
The tensile elastic modulus G2 of the translucent resin layer may be set so that the tensile elastic modulus G of the laminated body satisfies the above range, and is not particularly limited, but may be, for example, 2.0 to 3.0 GPa. When the tensile elastic modulus G2 of the translucent resin layer is 2.0 GPa or more, winding deformation can be less likely to occur while the laminated body or the rolled body of the polarizing plate is stored. When the tensile elastic modulus G2 of the translucent resin layer is 3.0 GPa or less, it is difficult to break the translucent resin layer when the laminated body is conveyed while applying tension, and the conveying stability can be improved.

The tensile elastic modulus G2 of the translucent resin layer can be adjusted mainly by the composition of the (meth) acrylic resin and the weight average molecular weight. When increasing the tensile elastic modulus G2 of the translucent resin layer, for example, it is preferable to increase the number of structural units (U2) derived from phenylmaleimide in the (meth) acrylic resin, and it is preferable to increase the weight average molecular weight. ..

The tensile elastic modulus G2 of the translucent resin layer can be measured by the same method as described above. That is, after the translucent resin layer is peeled off from the support, the tensile elastic modulus G2 of the translucent resin layer is measured by the same method as described above. If the translucent resin layer has anisotropy, prepare two types of samples, one in the orientation direction (in-plane slow phase axis direction) and the other in the direction orthogonal to it, measure each of them, and take the average value of them. ..

The difference ΔG (G1-G2) between the tensile elastic modulus G1 of the support and the tensile elastic modulus G2 of the translucent resin layer is preferably 3.5 GPa or less, and more preferably 2.5 GPa or less. When ΔG is 3.5 GPa or less, for example, when a winding tension is applied, the difference in the amount of deformation due to tension such as crease is small, so that peeling and breakage due to peeling are unlikely to occur.

(Internal haze)
The internal haze of the translucent resin layer is preferably 1.0% or less, more preferably 0.1% or less, and even more preferably 0.05% or less. The internal haze of the translucent resin layer can be measured by the same method as described above. The internal haze of the translucent resin layer can be adjusted by the content of rubber particles and the like.

(Phase difference Ro and Rt)
From the viewpoint of using the translucent resin layer as a retardation film for IPS mode, for example, the in-plane retardation Ro measured in an environment with a measurement wavelength of 550 nm and 23 ° C. and 55% RH is 0 to 10 nm. It is preferably 0 to 5 nm, and more preferably 0 to 5 nm. The phase difference Rt in the thickness direction of the translucent resin layer is preferably −20 to 20 nm, and more preferably −10 to 10 nm.

Ro and Rt are defined by the following equations, respectively.
Equation (2a): Ro = (nx-ny) × d
Equation (2b): Rt = ((nx + ny) /2-nz) × d
(During the ceremony,
nx represents the refractive index of the translucent resin layer in the in-plane slow-phase axial direction (the direction in which the refractive index is maximized).
ny represents the refractive index of the translucent resin layer in the direction orthogonal to the in-plane slow-phase axis.
nz represents the refractive index in the thickness direction of the translucent resin layer.
d represents the thickness (nm) of the translucent resin layer. )

The in-plane slow-phase axis of the translucent resin layer can be confirmed by an automatic birefringence meter Axoscan (AxoScan Mueller Matrix Polarimeter: manufactured by Axometrics).

Ro and Rt can be measured by the following methods.
1) The translucent resin layer is humidity-controlled for 24 hours in an environment of 23 ° C. and 55% RH. The average refractive index of this film is measured with an Abbe refractometer, and the thickness d is measured with a commercially available micrometer.
2) The retardation Ro and Rt of the film after humidity control at a measurement wavelength of 550 nm were measured at 23 ° C. and 55% RH using an automatic birefringence meter Axoscan (Axo Scan Mueller Matrix Polarimeter). Measure in the environment.

The phase difference Ro and Rt of the translucent resin layer can be adjusted by, for example, the monomer composition of the (meth) acrylic resin.

(Amount of residual solvent)
Since the translucent resin layer is obtained by applying a solution for the translucent resin layer, a solvent derived from the solution (for example, ketones and alcohols) may remain. The amount of residual solvent is preferably 700 ppm or less, more preferably 30 to 700 ppm, based on the translucent resin layer. The content of the residual solvent can be adjusted by the drying conditions of the solution for the translucent resin layer applied on the support in the manufacturing process of the translucent resin layer.

The amount of residual solvent in the translucent resin layer can be measured by headspace gas chromatography. In the headspace gas chromatography method, a sample is sealed in a container, heated, and the gas in the container is promptly injected into a gas chromatograph with the container filled with volatile components, and mass spectrometry is performed to identify the compound. The volatile components are quantified while doing so. The headspace method makes it possible to observe all peaks of volatile components by gas chromatography, and by using an analytical method that utilizes electromagnetic interactions, it is possible to quantify volatile substances and monomers with high accuracy. It can be done at the same time.

(Thickness)
The thickness of the translucent resin layer is not particularly limited, but from the viewpoint of realizing a thin polarizing plate, it is usually thinner than the thickness of the support, specifically, for example, 0.1 to 35 μm. It is preferably 1 to 15 μm, more preferably 1 to 15 μm.

The ratio T2 / T1 of the thickness T1 of the support to the thickness T2 of the translucent resin layer is preferably 0.01 to 1, and more preferably 0.1 to 0.7.

1-3. Other Layers The laminate according to the present embodiment may further have other layers arranged between the support and the translucent resin layer, if necessary.

1-4. Form of Laminated Body The form of the laminated body according to the present embodiment may be strip-shaped. That is, the laminated body according to the present embodiment can be wound into a roll shape in a direction orthogonal to the width direction thereof to form a roll body.

2. Laminated body manufacturing method [Manufacturing method]
The method for producing the laminate according to the present embodiment includes 1) a step of obtaining a translucent resin layer solution, and 2) a step of applying the obtained translucent resin layer solution to the surface of the support. 3) The present invention includes a step of removing the solvent from the applied solution for the translucent resin layer to form the translucent resin layer.

Regarding step 1) (step of obtaining a solution for a translucent resin layer), a solution for a translucent resin layer containing the above-mentioned (meth) acrylic resin, the above-mentioned rubber particles, and a solvent is prepared.

The solvent used for the translucent resin layer solution is not particularly limited as long as it can disperse (meth) acrylic resin and rubber particles well. Examples of solvents include alcohols such as methanol, ethanol, propanol, n-butanol, 2-butanol, tert-butanol and cyclohexanol, ketones such as methyl ethyl ketone, methyl isobutyl ketone and acetone, ethyl acetate, methyl acetate and lactic acid. Esters such as ethyl, isopropyl acetate, amyl acetate, ethyl butyrate, glycol ethers (propylene glycol mono (C1 to C4) alkyl ethers (specifically, propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether, propylene glycol) Mono-n-propyl ether, propylene glycol monoisopropyl ether, propylene glycol monobutyl ether, etc.), propylene glycol mono (C1-C4) alkyl ether esters (propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate)), toluene, benzene , Cyclohexane, n-hexane and other hydrocarbons are included. Among them, the solvent preferably contains ketones from the viewpoint of easily dissolving the (meth) acrylic resin, having a relatively high affinity with rubber particles, having a low boiling point, and easily increasing the drying rate and productivity. From the viewpoint of easily forming a translucent resin layer having high flatness, it is preferable to further contain alcohols.

That is, the solvent preferably contains ketones and alcohols. The content ratio of ketones and alcohols is not particularly limited, but from the viewpoint of achieving both drying speed and flatness, ketones / alcohols = 95/5 to 10/90 (mass ratio) is preferable, and 95 It is more preferably / 5 to 60/40 (mass ratio), and further preferably 95/5 to 80/20 (mass ratio). When the proportion of ketones is moderately high, the drying rate is likely to be increased and the productivity is likely to be increased. When the proportion of alcohols is moderately high, it is easy to improve the flatness of the coating film.

The resin concentration of the translucent resin layer solution is preferably, for example, 1.0 to 20% by mass from the viewpoint of making it easy to adjust the viscosity within the range described later.

The viscosity of the solution for the translucent resin layer is not particularly limited as long as it can form a translucent resin layer having a desired thickness, but is preferably 5 to 5000 cP, for example. When the viscosity of the solution for the translucent resin layer is 5 cP or more, it is easy to form a translucent resin layer having an appropriate thickness, and when it is 5000 cP or less, it is possible to suppress the occurrence of thickness unevenness due to the increase in the viscosity of the solution. sell. From the same viewpoint, the viscosity of the translucent resin layer solution is more preferably 100 to 1000 cP. The viscosity of the translucent resin layer solution can be measured with an E-type viscometer at 25 ° C.

Regarding the step 2) (step of applying the translucent resin layer solution), the obtained translucent resin layer solution is then applied to the surface of the support. Specifically, the obtained translucent resin layer solution is applied to the surface of the support.

The method for applying the solution for the translucent resin layer is not particularly limited, and may be a known method such as a back roll coating method, a gravure coating method, a spin coating method, a wire bar coating method, or a roll coating method. Above all, the back coat method is preferable from the viewpoint of being able to form a thin and uniform thickness coating film.

About the step 3) (step of forming the translucent resin layer) Next, the solvent is removed from the solution for the translucent resin layer applied to the support to form the translucent resin layer.

Specifically, the solution for the translucent resin layer applied to the support is dried. Drying can be performed, for example, by blowing air or heating. Above all, from the viewpoint of facilitating curling of the laminated body, it is preferable to dry it by blowing air.

By adjusting the drying conditions (for example, drying temperature, solvent concentration in the atmosphere, drying time, etc.), the amount of residual solvent in the coating film after drying, that is, the translucent resin layer, is kept below a certain level. Further, the distribution state of the rubber particles in the translucent resin layer can be adjusted depending on the drying conditions. Specifically, from the viewpoint of facilitating uneven distribution of rubber particles, it is preferable to use a solvent having a good affinity with the rubber particles, and it is preferable to raise the drying temperature and lower the solvent concentration in the atmosphere.

The drying temperature is preferably (Tb-50) to (Tb + 50) ° C., more preferably (Tb-40) to (Tb + 40) ° C., when the boiling point of the solvent is Tb (° C.). When the drying temperature is at least the lower limit value, the evaporation rate of the solvent can be increased, so that the rubber particles are likely to be unevenly distributed, and when it is at least the upper limit value, the solvent concentration in the atmosphere can be prevented from becoming too high. For example, when a mixed solvent of acetone / methanol is used, the drying temperature can be 40 ° C. or higher.

The solvent concentration in the atmosphere at the time of drying is preferably 0.10 to 0.30% by mass, more preferably 0.10 to 0.20% by mass. When the solvent concentration in the atmosphere is 0.1% by mass or more, the solvent does not evaporate too much, so that the coating film is less likely to crack. When the solvent concentration is 0.3% by mass or less, the evaporation rate of the solvent from the coating film is likely to be appropriately increased, so that the rubber particles are likely to be unevenly distributed on the surface. The solvent concentration in the atmosphere can be adjusted by the drying temperature and the dew point temperature in the drying furnace. Further, the solvent concentration in the atmosphere can be measured by an infrared gas densitometer.

The laminate according to the present embodiment may be strip-shaped as described above. Therefore, it is preferable that the method for producing the laminated body according to the present embodiment further includes 4) a step of winding the strip-shaped laminated body into a roll shape to form a roll body.

Step 4) (Step of winding the laminated body to obtain a roll body) The obtained strip-shaped laminated body is wound into a roll shape in a direction orthogonal to the width direction thereof to obtain a roll body.

The length of the strip-shaped laminate is not particularly limited, but may be, for example, about 100 to 10000 m. The width of the strip-shaped laminate is preferably 1 m or more, and more preferably 1.3 to 4 m.

[manufacturing device]
The method for manufacturing the laminate according to the present embodiment can be performed by, for example, the manufacturing apparatus shown in FIG.

FIG. 2 is a schematic view of a manufacturing apparatus 200 for carrying out the method for manufacturing a laminated body according to the present embodiment. The manufacturing apparatus 200 includes a supply unit 210, a coating unit 220, a drying unit 230, a cooling unit 240, and a winding unit 250. Reference numerals a to d indicate transport rolls for transporting the support 110.

The supply unit 210 has a feeding device (not shown) for feeding out the roll body 201 of the strip-shaped support 110 wound around the winding core.

The coating unit 220 is a coating device, and has a backup roll 221 that holds the support 110, and a coating head 222 that applies a translucent resin layer solution to the support 110 held by the backup roll 221. It has a decompression chamber 223 provided on the upstream side of the head 222.

The flow rate of the translucent resin layer solution discharged from the coating head 222 can be adjusted by a pump (not shown). The flow rate of the translucent resin layer solution discharged from the coating head 222 is set to an amount capable of stably forming a coating layer having a predetermined film thickness when continuously coated under the conditions of the coating head 222 adjusted in advance. There is.

The decompression chamber 223 is a mechanism for stabilizing the bead (pool of coating liquid) formed between the solution for the translucent resin layer from the coating head 222 and the support 110 at the time of coating, and reduces the degree of decompression. It is adjustable. The decompression chamber 223 is connected to a decompression blower (not shown) so that the inside is decompressed. The pressure reducing chamber 223 is in a state where there is no air leakage, and the gap between the pressure reducing chamber 223 and the backup roll is narrowly adjusted so that a stable bead of the coating liquid can be formed.

The drying unit 230 is a drying device that dries the coating film applied to the surface of the support 110, and has a drying chamber 231, a drying gas introduction port 232, and a discharge port 233. The temperature and air volume of the dry air are appropriately determined depending on the type of the coating film and the type of the support 110. By setting conditions such as the temperature and air volume of the drying air and the drying time in the drying unit 230, the residual solvent content of the coating film after drying can be adjusted. The amount of residual solvent in the coating film after drying can be measured by comparing the unit mass of the coating film after drying with the mass after the coating film is sufficiently dried.

The cooling unit 240 cools the temperature of the support 110 having the coating film (translucent resin layer 120) obtained by drying in the drying unit 230, and adjusts the temperature to an appropriate temperature. The cooling unit 240 has a cooling chamber 241, a cooling air inlet 242, and a cooling air outlet 243. The temperature and air volume of the cooling air can be appropriately determined depending on the type of the coating film and the type of the support 110. Further, even if the cooling unit 240 is not provided, the cooling unit 240 may not be provided if the cooling temperature is appropriate.

The winding unit 250 is a winding device (not shown) for winding the support 110 (laminated body 100) on which the translucent resin layer 120 is formed to obtain the roll body 251.

3. 3. Polarizing plate The polarizing plate has a polarizing element and a translucent resin layer arranged on at least one surface thereof. It is preferable that the polarizer and the translucent resin layer are adhered to each other via an adhesive layer.

FIG. 3 is a cross-sectional view showing a polarizing plate 300 according to an embodiment of the present invention.

As shown in FIG. 3, the polarizing plate 300 according to the present embodiment includes a polarizing element 310 (polarizer), a translucent resin layer 120 (protective film) arranged on one surface thereof, and the other. A protective film 320 (another protective film) arranged on the surface and two adhesive layers 330 (adhesive layer) arranged between the translucent resin layer 120 or the protective film 320 and the polarizing element 310. Have.

Further, the polarizing plate 300 may further have an adhesive layer 340 arranged on the surface of the translucent resin layer 120 opposite to the polarizer 310. The pressure-sensitive adhesive layer 340 is a layer for attaching the polarizing plate 300 to a display element (not shown) such as a liquid crystal cell. The surface of the pressure-sensitive adhesive layer 340 is usually protected by a release film (not shown).

3-1. Polarizer A polarizing element is an element that allows only light on a plane of polarization in a certain direction to pass through. The polarizer can usually be a polyvinyl alcohol-based polarizing film. Examples of the polyvinyl alcohol-based polarizing film include a polyvinyl alcohol-based film dyed with iodine and a film dyed with a dichroic dye.

The polyvinyl alcohol-based polarizing film may be a film obtained by uniaxially stretching a polyvinyl alcohol-based film and then dyeing it with iodine or a bicolor dye (preferably a film further subjected to a durability treatment with a boron compound); polyvinyl. An alcohol-based film may be a film that has been dyed with iodine or a bicolor dye and then uniaxially stretched (preferably a film that has been further subjected to a durability treatment with a boron compound). The absorption axis of the polarizer is usually parallel to the maximum stretching direction.

The thickness of the polarizer is preferably 5 to 30 μm, and more preferably 5 to 20 μm from the viewpoint of thinning the polarizing plate.

3-2. Translucent resin layer and other protective film A translucent resin layer is arranged on at least one surface of the polarizer. The translucent resin layer is obtained by transferring the translucent resin layer of the above-mentioned laminate onto the surface of the polarizer, and can function as a protective film. In the present embodiment, the translucent resin layer is arranged on one surface of the polarizer, and the other protective film is arranged on the other surface.

Examples of other protective films include (meth) acrylic resin, polyester resin, cycloolefin resin, and cellulose ester resin, and may be (meth) acrylic resin and polyester resin.

3-3. Adhesive layer The adhesive layer is arranged between the translucent resin layer and the polarizer, and between the other protective film and the polarizer, respectively. The adhesive layer arranged between the translucent resin layer and the polarizer and the adhesive layer arranged between the other protective film and the polarizer may be the same or different. May be good.

The adhesive layer may be a layer obtained from a completely saponified polyvinyl alcohol aqueous solution (water glue), or may be a cured product layer of an active energy ray-curable adhesive. From the viewpoint of having high affinity with the translucent resin layer and facilitating good adhesion, the adhesive layer is preferably a cured product layer of an active energy ray-curable adhesive.

The active energy ray-curable adhesive may be a photoradical polymerizable composition or a photocationic polymerizable composition. Of these, a photocationically polymerizable composition is preferable.

The photocationic polymerizable composition contains an epoxy compound and a photocationic polymerization initiator.

The epoxy compound is a compound having one or more, preferably two or more epoxy groups in the molecule. Examples of epoxy compounds include hydride epoxy compounds obtained by reacting an alicyclic polyol with epichlorohydrin (glycidyl ether of a polyol having an alicyclic ring); an aliphatic polyhydric alcohol or an alkylene thereof. Aliphatic epoxy compounds such as polyglycidyl ether as an oxide adduct; alicyclic epoxy compounds having one or more epoxy groups bonded to an alicyclic ring in the molecule are included. Only one type of epoxy compound may be used, or two or more types may be used in combination.

The photocationic polymerization initiator may be, for example, an aromatic diazonium salt; an onium salt such as an aromatic iodonium salt or an aromatic sulfonium salt; an iron-alene complex or the like.

Photocationic polymerization initiators include cationic polymerization accelerators such as oxetane and polyols, photosensitizers, ion trapping agents, antioxidants, chain transfer agents, tackifiers, thermoplastic resins, fillers, and fluids, if necessary. Additives such as modifiers, plasticizers, defoamers, antistatic agents, leveling agents, solvents and the like may be further included.

The thickness of the adhesive layer is not particularly limited, but is preferably 0.01 to 10 μm, and more preferably 0.01 to 5 μm, respectively.

3-4. Adhesive layer The adhesive layer is a layer for bonding a polarizing plate to a display element such as a liquid crystal cell, and may be arranged on a surface of the translucent resin layer opposite to the polarizing element.

The pressure-sensitive adhesive layer is preferably a dry and partially cross-linked pressure-sensitive adhesive composition containing a base polymer, a prepolymer and / or a cross-linking monomer, a cross-linking agent and a solvent. That is, at least a part of the pressure-sensitive adhesive composition may be crosslinked.

Examples of the pressure-sensitive adhesive composition include an acrylic pressure-sensitive adhesive composition using a (meth) acrylic polymer as a base polymer, a silicone-based pressure-sensitive adhesive composition using a silicone-based polymer as a base polymer, and a rubber-based pressure-sensitive adhesive composition using a rubber as a base polymer. A pressure-sensitive adhesive composition is included. Above all, an acrylic pressure-sensitive adhesive composition is preferable from the viewpoint of transparency, weather resistance, heat resistance, and processability.

The (meth) acrylic polymer contained in the acrylic pressure-sensitive adhesive composition can be a copolymer of a (meth) acrylic acid alkyl ester, a cross-linking agent, and a cross-linkable functional group-containing monomer.

The (meth) acrylic acid alkyl ester is preferably an acrylic acid alkyl ester having 2 to 14 carbon atoms in the alkyl group.

Examples of the functional group-containing monomer that can be crosslinked with the cross-linking agent include an amide group-containing monomer, a carboxyl group-containing monomer (acrylic acid, etc.), and a hydroxyl group-containing monomer (hydroxyethyl acrylate, etc.).

Examples of the cross-linking agent contained in the acrylic pressure-sensitive adhesive composition include an epoxy-based cross-linking agent, an isocyanate-based cross-linking agent, and a peroxide-based cross-linking agent. The content of the cross-linking agent in the pressure-sensitive adhesive composition can be, for example, 0.01 to 10 parts by mass with respect to 100 parts by mass of the base polymer (solid content).

Adhesive compositions include tackifiers, plasticizers, fiberglass, glass beads, metal powders, other fillers, pigments, colorants, fillers, antioxidants, UV absorbers, silane couplings as needed. Various additives such as agents may be further included.

The thickness of the pressure-sensitive adhesive layer is usually about 3 to 100 μm, preferably 5 to 50 μm.

The surface of the adhesive layer is protected by a release film that has undergone a mold release treatment. Examples of the release film include a plastic film such as an acrylic film, a polycarbonate film, a polyester film, and a fluororesin film.

4. Method for manufacturing a polarizing plate The polarizing plate according to the present embodiment can be manufactured through a step of attaching a translucent resin layer of the above-mentioned laminate to at least one surface of a polarizing element and peeling off a support. .. The translucent resin layer may be bonded to only one surface of the polarizer or both surfaces, and from the viewpoint of transmittance, the translucent resin may be attached to one surface of the polarizer. It is preferable to attach the layers and attach another protective film to the other surface.

That is, the polarizing plate is 1) a support in which the translucent resin layer of the laminated body is bonded to one surface of the polarizing element and is arranged on the surface of the translucent resin layer opposite to the polarizing element. It can be manufactured through a step of peeling off and 2) a step of attaching another protective film to the other surface of the polarizer.

Regarding step 1) (step of laminating the translucent resin layer), the translucent resin layer of the laminate is bonded to one surface of the polarizer via an adhesive. If necessary, a pretreatment such as a corona treatment may be applied to the surface of the translucent resin layer to be bonded or one surface of the polarizer.

For example, when an active energy ray-curable adhesive is used as the adhesive, the surface of the translucent resin layer of the laminated body is subjected to surface treatment such as corona treatment as necessary. Next, the translucent resin layer of the laminated body is laminated on one surface of the polarizer via an active energy ray-curable adhesive, and then the translucent resin layer is arranged on the side opposite to the bonded surface. Peel off the support. Next, the exposed translucent resin layer is irradiated with active energy rays to cure the active energy ray-curable adhesive. As a result, the polarizer and the translucent resin layer are bonded to each other via the cured product layer of the active energy ray-curable adhesive.

Regarding step 2) (protective film bonding step), another protective film is bonded to the other surface of the polarizer. Specifically, the surface of the other protective film is subjected to a surface treatment such as a corona treatment, if necessary. Next, the protective film is laminated on the other surface of the polarizer via the active energy ray-curable adhesive, and then irradiated with active energy rays to cure the active energy ray-curable adhesive. As a result, the polarizer and the other protective film are adhered to each other via the cured product layer of the active energy ray-curable adhesive.

The steps 1) and 2) may be performed simultaneously or sequentially. From the viewpoint of increasing production efficiency, it is preferable that the steps 1) and 2) are performed at the same time.

Further, the method for producing a polarizing plate according to the present embodiment may further include a step of forming a 3) pressure-sensitive adhesive layer after the step of 2), if necessary.

Regarding the step 3) (step of forming the pressure-sensitive adhesive layer) Next, the pressure-sensitive adhesive layer and its release film are further bonded to the surface of the obtained laminate on the side opposite to the polarizer of the translucent resin layer. .. Specifically, the pressure-sensitive adhesive layer can be formed by a method such as transferring a release film provided with the pressure-sensitive adhesive layer on the translucent resin layer.

The polarizing plate according to the present embodiment may be band-shaped. Therefore, in the steps 1) and 2), the translucent resin layer of the strip-shaped laminate, the strip-shaped polarizer, and the other strip-shaped protective film (opposing film) are unwound from the roll body, respectively. , It is preferable to carry out by laminating by roll-to-roll.

Further, it is preferable to further perform the step of 4) winding the strip-shaped polarizing plate into a roll shape to form a roll body. In this step, the length and width of the strip-shaped polarizing plate are the same as the length and width of the strip-shaped laminate in the step 4) of the method for manufacturing the laminate.

5. Display device The display device according to the present embodiment includes a display element such as a liquid crystal cell or an organic EL element, and a polarizing plate manufactured by the above manufacturing method. Above all, the display device according to the present embodiment is preferably a liquid crystal display device having a liquid crystal cell and a polarizing plate manufactured by the above manufacturing method.

That is, the liquid crystal display device includes a liquid crystal cell, a first polarizing plate arranged on one surface of the liquid crystal cell, and a second polarizing plate arranged on the other surface of the liquid crystal cell. Then, at least one of the first polarizing plate and the second polarizing plate is the polarizing plate according to the present embodiment.

The display modes of the liquid crystal cells are, for example, STN (Super-Twisted Nematic), TN (Twisted Nematic), OCB (Optically Compensated Bend), HAN (Hybridaligned Nematic), VA (Vertical Alignment, MVA (Multi-domain Vertical Alignment), PVA). (Patterned Vertical Alignment)), IPS (In-Plane-Switching), etc. For example, in a liquid crystal display device for mobile devices, the IPS mode is preferable.

The first polarizing plate is arranged on the surface of the liquid crystal cell on the visual side via its adhesive layer. The first polarizing plate includes a first polarizing element, a protective film (F1) arranged on the surface of the first polarizing element on the visible side, and a protective film (F2) arranged on the surface of the first polarizing element on the liquid crystal cell side. ), And two adhesive layers arranged between the first polarizer and the protective film (F1) and between the first polarizer and the protective film (F2).

The second polarizing plate is arranged on the backlight side surface of the liquid crystal cell via its adhesive layer. The second polarizing plate includes a second polarizing element, a protective film (F3) arranged on the surface of the second polarizing element on the liquid crystal cell side, and a protective film (F3) arranged on the surface of the second polarizing element on the backlight side. Includes F4) and two adhesive layers disposed between the second polarizer and the protective film (F3) and between the second polarizer and the protective film (F4).

It is preferable that the absorption axis of the first polarizer and the absorption axis of the second polarizer are orthogonal to each other (cross Nicol).

Then, at least one of the first polarizing plate and the second polarizing plate is the polarizing plate according to the present embodiment. That is, when the first polarizing plate is the above-mentioned polarizing plate, the protective film (F1) is the protective film 320 of FIG. 3, and the protective film (F2) is the translucent resin layer 120 of FIG. The pressure-sensitive adhesive layer can be the pressure-sensitive adhesive layer 340 of FIG. Similarly, when the second polarizing plate is the above-mentioned polarizing plate, the protective film (F4) is the protective film 320 of FIG. 3, and the protective film (F3) is the translucent resin layer 120 of FIG. , The pressure-sensitive adhesive layer can be the pressure-sensitive adhesive layer 340 of FIG.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.

1. 1. Laminate material 1-1. Support <PET-1>
A polyethylene terephthalate film (TZ200 manufactured by Toyobo Co., Ltd., with a release layer (containing a silicone-based release agent, thickness 50 μm)) was used.

<PET-2>
A polyethylene terephthalate film (TN100 manufactured by Toyobo Co., Ltd., with a release layer (containing a non-silicone release agent, thickness 50 μm)) was stretched (additionally stretched) by 50% in the TD direction at 140 ° C.

<PET-3>
A polyethylene terephthalate film (TN100 manufactured by Toyobo Co., Ltd., with a release layer (containing a non-silicone release agent, thickness 50 μm)) was stretched (additionally stretched) by 50% in each of the TD direction and the MD direction at 140 ° C.

<TAC>
Cellulose triacetate film (Konica Minolta KC4UA, no release layer, thickness 40 μm)

<COP>
Cycloolefin resin film (RX4500 manufactured by JSR, no release layer, thickness 50 μm)

<HDPE>
High-density polyethylene film (thickness 50 μm)

The tensile elastic modulus G1 of these supports was measured by the following method.

(Tensile modulus G1)
The support was cut into 1 cm × 10 cm to prepare a sample, and the humidity was adjusted for 24 hours in an environment of 25 ° C. and 60% RH. Then, the tensile elastic modulus of the obtained sample was measured by the tensile test method described in JIS K7127. Specifically, the sample was set in a tensile test device Tencilon manufactured by Orientec Co., Ltd., and the tensile elastic modulus was measured when the tensile test was performed under the conditions of a distance between chucks of 50.0 mm and a tensile speed of 50 mm / min. The measurement was performed at 25 ° C. and 60% RH. The tensile elastic modulus was measured in both the MD direction and the TD direction, and the average value of the tensile elastic modulus in the MD direction and the tensile elastic modulus in the TD direction was defined as "tensile elastic modulus G1".

1-2. Solution for translucent resin layer (1) Preparation of materials <Resin>
Resin 1: PMMA, Mw: 1 million, Tg: 109 ° C
Resin 2: MMA / PMI / MA copolymer (85/10/5 mass ratio), Mw: 1 million, Tg: 122 ° C.
Resin 3: MMA / PMI / MA copolymer (85/10/5 mass ratio), Mw: 2 million, Tg: 122 ° C.
Resin 4: MMA / PMI / MA copolymer (50/25/25 mass ratio), Mw: 1 million, Tg: 134 ° C.
Resin 5: MMA / PMI / MA copolymer (85/10/5 mass ratio), Mw: 500,000, Tg: 122 ° C.
The abbreviations are as follows.
MMA: Methyl Methacrylate PMI: Phenylmaleimide MA: Methyl Acrylate

The glass transition temperature and weight average molecular weight of resins 1 to 5 were measured by the following methods.

(Glass-transition temperature)
The glass transition temperature (Tg) of the resin was measured using DSC (Differential Scanning Colorimetry) according to JIS K 7121-2012.

(Weight average molecular weight)
The weight average molecular weight (Mw) of the resin was measured using gel permeation chromatography (HLC8220GPC manufactured by Tosoh Corporation) and a column (TSK-GEL G6000HXL-G5000HXL-G5000HXL-G4000HXL-G3000HXL series manufactured by Tosoh Corporation). 20 mg ± 0.5 mg of the sample was dissolved in 10 ml of tetrahydrofuran and filtered through a 0.45 mm filter. 100 ml of this solution was injected into a column (temperature 40 ° C.), measured at a detector RI temperature of 40 ° C., and a styrene-converted value was used.

<Rubber particles>
The rubber particles R1 prepared by the following method were used.
The following substances were charged into an 8L polymerization apparatus equipped with a stirrer.
Deionized water 180 parts by mass Polyoxyethylene lauryl ether phosphoric acid 0.002 parts by mass Boric acid 0.4725 parts by mass Sodium carbonate 0.04725 parts by mass Sodium hydroxide 0.0076 parts by mass The inside of the polymerization machine was sufficiently replaced with nitrogen gas. After that, the internal temperature was adjusted to 80 ° C., and 0.021 parts by mass of potassium persulfate was added as a 2% aqueous solution. Next, a monomer consisting of 84.6% by mass of methyl methacrylate, 5.9% by mass of butyl acrylate, 7.9% by mass of styrene, 0.5% by mass of allyl methacrylate, and 1.1% by mass of n-octyl mercaptan. A mixed solution prepared by adding 0.07 parts by mass of polyoxyethylene lauryl ether phosphoric acid to 21 parts by mass of the mixture (c') was continuously added to the above solution over 63 minutes. Further, the innermost hard polymer (c) was obtained by continuing the polymerization reaction for 60 minutes.

Then, 0.021 parts by mass of sodium hydroxide was added as a 2% by mass aqueous solution, and 0.062 parts by mass of potassium persulfate was added as a 2% by mass aqueous solution. Next, 0.25 polyoxyethylene lauryl ether phosphoric acid was added to 39 parts by mass of the monomer mixture (a') consisting of 80.0% by mass of butyl acrylate, 18.5% by mass of styrene, and 1.5% by mass of allyl methacrylate. The mixed solution to which the mass part was added was continuously added over 117 minutes. After completion of the addition, 0.012 parts by mass of potassium persulfate was added in a 2% by mass aqueous solution, and the polymerization reaction was continued for 120 minutes to obtain a soft layer (a layer made of an acrylic rubber-like polymer (a)). The glass transition temperature (Tg) of the soft layer was −30 ° C. The glass transition temperature of the soft layer was calculated by averaging the glass transition temperature of the homopolymer of each monomer constituting the acrylic rubber-like polymer (a) according to the composition ratio.

Then, 0.04 parts by mass of potassium persulfate was added in a 2% by mass aqueous solution, and 26.1% by mass of a monomer mixture (b') consisting of 97.5% by mass of methyl methacrylate and 2.5% by mass of butyl acrylate was added. The portions were added continuously over 78 minutes. The polymerization reaction was continued for another 30 minutes to obtain a polymer (b).

The obtained polymer was put into a warm aqueous solution of 3% by mass sodium sulfate for salting out and coagulation. Then, after repeating dehydration and washing, the particles were dried to obtain acrylic graft copolymer particles (rubber particles R1) having a three-layer structure. The average particle size of the obtained rubber particles R1 was 200 nm.

The average particle size of the rubber particles was measured by the following method.

(Average particle size)
The dispersed particle size of the rubber particles in the obtained dispersion was measured by a zeta potential / particle size measuring system (ELSZ-2000ZS manufactured by Otsuka Electronics Co., Ltd.).

(2) Preparation of a solution for a translucent resin layer <Preparation of a solution 101 for a translucent resin layer>
The following components were mixed to obtain a solution for a translucent resin layer.
Acetone (ketones): 1012.5 parts by mass Methanol (alcohols): 112.5 parts by mass Resin 1 ((meth) acrylic resin): 100 parts by mass Rubber particles: 25 parts by mass

<Preparation of solutions 102 to 109 for translucent resin layer>
Solutions 102 to 109 for the translucent resin layer were obtained in the same manner as the translucent resin layer solution 101 except that the composition was changed to that shown in Table 1.

Table 1 shows the compositions and viscosities of the obtained translucent resin layer solutions 101 to 109. The viscosity of the translucent resin layer solution at 25 ° C. was measured with an E-type viscometer manufactured by Toki Sangyo Co., Ltd.

2. Fabrication and evaluation of laminate <Preparation of laminate 201>
As a support, a PET film (TN100 manufactured by Toyobo Co., Ltd., a thickness of 50 μm, a release layer containing a non-silicone release agent, PET-1 in the table) was prepared. A solution 101 for a translucent resin layer is applied onto the release layer of this PET film by a backcoat method using a die, and then dried at 80 ° C. in an atmosphere having a solvent concentration of 0.18% to obtain a thickness. A 10 μm translucent resin layer was formed to obtain a laminate 201.

<Preparation of laminates 202 to 203, 205, 210, 212, 213, 216, 217 and 219>
Laminates 202 to 203, 205, 210, 212, 213, 217 and 219 were obtained in the same manner as the laminate 201 except that the type of the solution for the translucent resin layer was changed as shown in Table 2.

<Manufacturing of laminated body 204>
A laminated body 204 was obtained in the same manner as the laminated body 202 except that the solvent concentration of the atmosphere was changed as shown in Table 2.

<Manufacturing of laminated bodies 211 and 214>
Laminated bodies 211 and 214 were obtained in the same manner as the laminated body 202 except that the types of the supports were changed as shown in Table 2.

<Preparation of laminates 215 and 218>
Laminated bodies 215 and 218 were obtained in the same manner as the laminated body 202 except that the thickness of the translucent resin layer was changed as shown in Table 2.

<Evaluation>
The distribution of rubber particles in the translucent resin layers of the obtained laminates 201 to 219, the tensile elastic modulus G and the transport stability of the laminate, and the winding deformation of the polarizing plate were evaluated by the following methods.

[Distribution of rubber particles]
Distribution of the rubber particles of the translucent resin layer of the resulting laminate _(R A _/ R _B), was measured by the following method.
1) The laminate was cut with a microtome, and the cut surface perpendicular to the surface of the translucent resin layer was observed by TEM. The observation conditions were an acceleration voltage of 30 kV, a working distance of 8.6 mm, and a magnification of 3.00 k. The observation region was a region including the entire thickness direction of the translucent resin layer.
2) The obtained TEM image was subjected to an opening process after removing the brightness gradient using image processing software of NiVision (manufactured by National Instruments), and the contrast difference between the bulk and the rubber particles was detected. As a result, the distribution state of the rubber particles was identified.
3) In the image after image processing obtained in 2) above, in the region A of 20% or less of the thickness from the surface opposite to the support of the translucent resin layer in the thickness direction of the translucent resin layer. area ratio R _a per unit area of the rubber _particles, per unit area of the rubber particles at 20% or less of the region B in terms of the thickness of the support side of the translucent resin layer and the area ratio R _B was calculated.
The results obtained in 4) above 3), the area ratio R _A per unit area of the rubber particles in the region A, the ratio to the area ratio R _B per unit area of the rubber particles in the region B (R A _/ R _B ) Was calculated.

[Tension modulus]
The laminate was subjected to a tensile test in accordance with JIS K7127 in the same manner as described above. That is, the laminate was cut into 1 cm (TD direction) × 10 cm (MD direction) to prepare a sample, and the humidity was adjusted for 24 hours in an environment of 25 ° C. and 60% RH. The obtained sample was set in a tensile test device Tencilon manufactured by Orientec Co., Ltd. and a tensile test was performed to measure the tensile elastic modulus G (tensile elastic modulus of the laminated body). The measurement conditions were the same as described above (distance between chucks: 50.0 mm, tensile speed: 50 mm / min, 25 ° C., 60% RH).

Regarding the translucent resin layer, after peeling the translucent resin layer from the support, the tensile elastic modulus G2 of the translucent resin layer was measured by the same method as described above.

[Transport stability]
The transport stability of the laminated body was evaluated by confirming the presence or absence of breakage or cracking during roll transport on the line while applying a transport tension of 350 N / m. Then, the transport stability was evaluated based on the following criteria.
⊚: The translucent resin layer can be transported without breaking ○: The translucent resin layer cracks but can be transported without breaking ○ △: Very small scratches and cracks on the translucent resin layer However, it can be transported. Δ: Small scratches and cracks occur in the translucent resin layer, but it can be transported. ×: The translucent resin layer cracks and breaks. ..

[Wound deformation defect of laminated body]
The obtained rolls were stored in a constant temperature bath at 40 ° C. and 90% RH for 8 days. Then, the roll body was taken out from the constant temperature bath, and the appearance of the roll body, specifically, the presence or absence of winding deformation such as a dent in the central portion in the width direction of the roll body was evaluated.
Then, the winding deformation was evaluated based on the following criteria.
◎: There is no deformation of the winding shape ○: There is some deformation of the winding shape, but it is at a usable level and there is no sticking ○ △: There is some deformation of the winding shape, and some sticking is seen, but it is used Possible level Δ: There is some deformation or sticking of the winding shape, but usable level ×: If the winding shape is significantly deformed and cannot be used, it is judged to be good.

[Polarizing plate winding deformation defect]
(Making a polarizer)
A polyvinyl alcohol-based film having a thickness of 25 μm was swollen with water at 35 ° C. The obtained film was immersed in an aqueous solution consisting of 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, and further immersed in an aqueous solution of 45 ° C. consisting of 3 g of potassium iodide, 7.5 g of boric acid and 100 g of water. .. The obtained film was uniaxially stretched under the conditions of a stretching temperature of 55 ° C. and a stretching ratio of 5 times. This uniaxially stretched film was washed with water and then dried to obtain a polarizer having a thickness of 12 μm.

(Preparation of UV curable adhesive composition)
After mixing the following components, defoaming was performed to prepare an ultraviolet curable adhesive composition.
3,4-Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate: 45 parts by mass Epolide GT-301 (alicyclic epoxy resin manufactured by Daicel): 40 parts by mass 1,4-butanediol diglycidyl ether: 15 parts by mass Parts by mass Triarylsulfonium hexafluorophosphate: 2.3 parts by mass (solid content)
9,10-Dibutoxyanthracene: 0.1 parts by mass 1,4-diethoxynaphthalene: 2.0 parts by mass Triarylsulfonium hexafluorophosphate was blended as a 50% propylene carbonate solution.

(Preparation of polarizing plate)
The surface of the translucent resin layer produced above was subjected to corona discharge treatment at a corona output strength of 2.0 kW and a line speed of 18 m / min. Similarly, triacetyl cellulose (thickness 25 μm) was prepared as another protective film (opposite film), and the surface was subjected to corona treatment under the same conditions as described above.

Then, a translucent resin layer is provided on one surface of the produced polarizing element via an ultraviolet curable adhesive layer having a thickness of 3 μm, and another surface is provided on the other surface via an ultraviolet curable adhesive layer having a thickness of 3 μm. The protective films of the above were bonded to each other to obtain a laminate. The bonding was performed so that the absorption axis of the polarizer and the slow axis of the protective film were orthogonal to each other.

^{Next, the obtained laminate was irradiated with ultraviolet rays so that the integrated light amount was 750 mJ / cm 2} using an ultraviolet irradiation device with a belt conveyor (the lamp uses a D valve manufactured by Fusion UV Systems). A roll of a polarizing plate 201 having a length of 3000 m and a width of 1.5 m, which has a laminated structure of an opposing film / adhesive layer / polarizer / adhesive layer / translucent resin layer by curing an ultraviolet curable adhesive layer. I got a body.

(Rolling deformation defect)
The winding deformation defect of the obtained roll body was evaluated by the same method and criteria as the winding deformation defect of the roll body of the laminated body.

Table 2 shows the production conditions of the obtained laminates 201 to 219, and Table 3 shows the evaluation results. In Table 2, 80 ° C. of ketone / alcohol (90/10 mass ratio) corresponds to about Tb ° C., and 40 ° C. of ketone / alcohol (10/90 mass ratio) corresponds to about Tb-40 ° C. However, 110 ° C. of ethyl acetate corresponds to Tb + 30 ° C.

As shown in Table 3, it can be seen that the laminated bodies 201 to 210 and 215 to 219 do not break during transportation and have good transportation stability. Further, it can be seen that even if the laminates 201 to 210 and 215 to 219 are wound into a roll and stored for a certain period of time, the winding deformation is unlikely to remain in the translucent resin layer, and the winding storage stability is also excellent. Further, it can be seen that even if the rolled body of the polarizing plate obtained by using such a laminated body is stored for a certain period of time, the winding deformation is unlikely to remain in the translucent resin layer.

Further, it can be seen that the winding deformation can be further reduced by increasing the weight average molecular weight of the (meth) acrylic resin (comparison between the laminated bodies 202 and 203).

Further, it can be seen that when the drying temperature is raised, the rubber particles tend to be unevenly distributed on the surface layer (contrast between the laminated bodies 202 and 209). It is considered that this is because the drying speed has increased. Further, it can be seen that the rubber particles are likely to be unevenly distributed on the surface layer by making the ratio of acetone and methanol rich in acetone (contrast between the laminated bodies 202 and 210). It is considered that this is because, in addition to the increased drying rate, acetone has a high affinity with the rubber particles, so that the rubber particles easily move together with the solvent.

On the other hand, it can be seen that the laminated body 211 having an excessively high tensile elastic modulus of the support is easily broken and is inferior in transport stability. On the other hand, it can be seen that the laminated body 214 having an excessively low tensile elastic modulus of the support is likely to undergo winding deformation of the laminated body, whereby the deformation is easily transferred to the translucent resin layer. Further, it can be seen that in the laminated body 213 in which the translucent resin layer does not contain rubber particles, the winding deformation is hard to disappear. Further, it can be seen that in the laminated body 212 having a low molecular weight of the resin contained in the translucent resin layer, the translucent resin layer is easily broken during transportation and the transportation stability is low.

100 Laminated body 110 Support 120 Translucent resin layer 200 Manufacturing equipment 210 Supply part 220 Coating part 230 Drying part 240 Cooling part 250 Winding part 300 Polarizing plate 310 Polarizer 320 Protective film (other protective film)
330 Adhesive layer 340 Adhesive layer

Claims

A laminate having a support and a translucent resin layer removably arranged on the surface thereof.
The translucent resin layer contains a (meth) acrylic resin having a weight average molecular weight of 1 million or more and rubber particles.
The laminate has a tensile elastic modulus of 2.0 to 6.0 GPa at 25 ° C.
The (meth) acrylic resin contains 50 to 95% by mass of a structural unit derived from methyl methacrylate and 1 to 25% by mass of phenylmaleimide with respect to all the structural units constituting the (meth) acrylic resin. A copolymer containing a structural unit derived from 1 to 25% by mass of a structural unit derived from acrylic acid alkyl ester.
The laminate according to claim 1.
In the cross section of the translucent resin layer,
The region A of 20% or less of the thickness of the translucent resin layer is formed from the surface of the translucent resin layer opposite to the support, and the translucency is formed from the surface of the translucent resin layer on the support side. A region of 20% or less of the thickness of the light resin layer is designated as region B.
When the area ratio R A per unit area of the rubber particles in the region A, the area ratio per unit area of the rubber particles in the region B was set to R B,
R A / R B is 1.0-1.1,
The laminate according to claim 1 or 2.
R A / R B is from 1.05 to 1.1
The laminate according to claim 3.
The content of the rubber particles in the translucent resin layer is 5 to 40% by mass with respect to the translucent resin layer.
The laminate according to any one of claims 1 to 4.
The thickness of the translucent resin layer is 0.1 to 35 μm.
The laminate according to any one of claims 1 to 5.
The support includes a film containing a polyester resin, a cellulose ester resin or a cycloolefin resin.
The laminate according to any one of claims 1 to 6.
A step of obtaining a solution for a translucent resin layer containing a (meth) acrylic resin having a weight average molecular weight of 1 million or more, rubber particles, and a solvent.
A step of applying the translucent resin layer solution to the surface of the support, and
A step of removing the solvent from the applied solution for the translucent resin layer to form a translucent resin layer to obtain a laminate having a tensile elastic modulus of 2.0 to 6.0 GPa at 25 ° C. Have,
Method for manufacturing a laminate.
The (meth) acrylic resin contains 50 to 95% by mass of a structural unit derived from methyl methacrylate and 1 to 25% by mass of phenylmaleimide with respect to all the structural units constituting the (meth) acrylic resin. A copolymer containing a structural unit derived from 1 to 25% by mass of a structural unit derived from acrylic acid alkyl ester.
The method for producing a laminate according to claim 8.
The solvent contains ketones and alcohols.
The method for producing a laminate according to claim 8 or 9.
In the step of forming the translucent resin layer,
When the boiling point of the solvent is Tb (° C.), the translucent resin layer solution applied to the surface of the support is dried at a temperature of (Tb-50) to (Tb + 50) ° C.
The method for producing a laminate according to any one of claims 8 to 10.
The thickness of the translucent resin layer is 0.1 to 35 μm.
The method for producing a laminate according to any one of claims 8 to 11.
The translucent resin layer of the laminate according to any one of claims 1 to 7 is bonded to at least one surface of the polarizer, and the side of the translucent resin layer opposite to the polarizer. It has a step of peeling off the support arranged on the surface of the surface.
Method for manufacturing a polarizing plate.