TWI725311B - Separator film laminated optical film with adhesive layer - Google Patents

Abstract

The objective of the present invention is to provide an optical film with adhesive layer, which has few depressions under pressure, and has excellent effect of preventing scratching and dent mark due to foreign matter, especially during storage, shipping and transportation.

The separator film laminated optical film with adhesive layer of the present invention includes: a separator film laminated on at least one side of an optical film (A) via an adhesive layer (B); wherein the separator film (C) has a film thickness of 45μm or more, and the optical film (A) has a film thickness of 100μm or less.

Description

Optical film with adhesive layer through laminated separation film

The present invention relates to an optical film with an adhesive layer attached to a laminated separation film.

An optical film represented by a polarizing plate formed by laminating a transparent resin film on one side or both surfaces of a polarizer is widely used as an optical member constituting an image display device such as a liquid crystal display device. Optical films such as polarizing plates and retardation plates are in most cases constructed in the form of an "adhesive layer-attached optical film" with an adhesive layer on one side, and most of them are formed through the adhesive layer. It is used by bonding to display elements such as liquid crystal cells or organic EL display elements. For such an optical film with an adhesive layer, in order to protect the adhesive layer before being attached to the display element, a separator film is usually laminated, which is peeled and removed when the adhesive layer is used (Patent Document 1).

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] International Publication No. 2009/069799

In recent years, image display devices have tended to be thinner. Therefore, optical film systems are expected to be thinner, for example, 100 μm or less. An adhesive layer is provided on such a thin optical film and a separation film is laminated on it to form an optical film (optical film with an adhesive layer through the laminated separation film). In most cases, it is wound into a roll Stored, transported or transported in a state of shape. At this time, when foreign matter such as dust is attached to the outer surface of the separation membrane, if the optical film with the adhesive layer of the laminated separation membrane is wound, it will be in storage due to the pressure between the wound membranes. When the optical film is pressed during transportation or transportation, even after the pressure is removed, damage and dents caused by foreign matter will remain on the optical film. Furthermore, there are cases where the optical film with the adhesive layer of the laminated separation film is cut into a size that matches the size of the display element to which it is bonded, stacked, stored, and transported. In this case, if there are foreign substances between the stacked optical films with the adhesive layer of the laminated separation film, damages and dents caused by the foreign substances will also remain on the optical film. Such damages and dents caused by foreign matter will cause defects in the optical properties of the optical film. Therefore, a laminated separation film with a high degree of "prevention of damage to the optical film and dents caused by foreign matter" is required. The optical film attached to the adhesive layer.

Therefore, the object of the present invention is to provide an optical film with an adhesive layer attached to a laminated separation film, which has less dents under pressure, especially for damages and dents caused by foreign objects during storage, transportation or transportation. The effect of preventing scars is good.

The inventors of the present invention have completed the present invention as a result of thorough examination in order to solve the above-mentioned problems.

That is, the present invention includes the following preferred aspects [1] to [3].

[1] An optical film with an adhesive layer attached to a laminated separation film, comprising: a separation film (C) laminated on at least one side of an optical film (A) via an adhesive layer (B); wherein, the aforementioned separation film The film thickness of (C) is 45 μm or more, and the film thickness of the aforementioned optical film (A) is 100 μm or less.

[2] The adhesive layer-attached optical film of a laminated separation film according to [1], wherein the separation film (C) is a separation film having a Vickers hardness of 15 or more on a single display surface.

[3] The adhesive layer-attached optical film of a laminated separation film as described in [1] or [2], wherein the separation film (C) is a separation film that independently exhibits a bending stiffness of 1 mg or more.

[4] The adhesive layer-attached optical film of the laminated separation film as described in any one of [1] to [3], wherein the storage elastic modulus G'of the adhesive layer (B) at 25°C is Below 0.4MPa.

According to the present invention, it is possible to provide an optical film with an adhesive layer attached to a laminated separation film, which has less dents under pressure, especially for damages and dents caused by foreign objects during storage, transportation, or transportation. The prevention effect is good.

1‧‧‧Optical film with adhesive layer through laminated separation film

2‧‧‧Polarizer

3‧‧‧(1st) Resin film

4‧‧‧(Second) Resin Film

5‧‧‧Protective film

6‧‧‧Hard coating

10‧‧‧Optical film

20‧‧‧Adhesive layer

30‧‧‧Separation membrane

Fig. 1 is a schematic cross-sectional view showing an example of the adhesive layer-attached optical film of the laminated separation film of the present invention.

Fig. 2 is a schematic cross-sectional view showing an example of the adhesive layer-attached optical film of the laminated separation film of the present invention.

<Optical film with adhesive layer through laminated separation film>

The adhesive layer-attached optical film of the laminated separation film of the present invention includes: an optical film (A); and a separation film laminated on at least the surface of the aforementioned optical film (A) via an adhesive layer (B) C).

In the adhesive layer-attached optical film of the laminated separation film of the present invention, the thickness of the separation film (C) is 45 μm or more. When the film thickness of the separation film (C) is less than 45μm, the dents caused by foreign matter attached to the surface of the separation film will easily spread to the adhesive layer, and it is difficult to sufficiently ensure the effect of preventing damage and dents on the optical film. . In the adhesive layer-attached optical film of the laminated separation film of the present invention, the thickness of the separation film (C) is preferably 45 μm or more, more preferably 47 μm or more, and particularly preferably 50 μm or more. Although the upper limit of the thickness of the separation membrane (C) is not particularly limited, it is usually 200 μm or less. From the viewpoint of facilitating peeling when the separation membrane is peeled off, for example, it is preferably 150 μm or less, and more preferably 100 μm. the following.

In the adhesive layer-attached optical film of the laminated separation film of the present invention, the film thickness of the optical film (A) is 100 μm or less. In the adhesive layer-attached optical film of the laminated separation film of the present invention, the thickness of the optical film (A) is preferably 80 μm or less, more preferably 70 μm or less. The lower limit of the film thickness of the optical film (A) is usually 5 m or more, and from the viewpoint of ease of handling, for example, it is preferably 10 m or more, more preferably 15 m or more.

Here, in the present invention, the so-called optical film refers to a film that functions for image display (display screen, etc.) (for example, a film that functions to improve the visibility of an image), and means that it can be incorporated into Films with various optical properties in image display devices such as liquid crystal display devices, for example, may have a single-layer structure (polarizer, retardation film, brightness enhancement film, anti-glare film, anti-reflection film, diffuser film, condensing film, etc.) Optical functional film, etc.), may have a multilayer structure (for example, polarizing plate, retardation plate, etc.).

In the present invention, the "thickness of the optical film (A)" refers to the thickness of a single layer when the optical film has a single-layer structure, and refers to the thickness of all layers constituting the multilayer structure when the optical film has a multilayer structure Sum. In addition, when the optical film has a multilayer structure, when the optical film is incorporated into an optical laminate or a display device, the layer that will be finally peeled off (such as a protective film) is not regarded as constituting the optical film (A The layer of) is not considered when calculating the film thickness of the optical film (A). Therefore, for example, in the adhesive layer-attached optical film of the laminated separation film of the present invention shown in Figure 1, the film thickness of the optical film (A) is the polarizer 2, the first resin film 3, and the second resin film 4 total thickness. Furthermore, in the optical film with the adhesive layer of the laminated separation film of the present invention shown in Figure 2, the thickness of the optical film (A) is the polarizer 2, the first resin film 3, and the second resin film 4. And the total thickness of the hard coat layer 6.

In the present invention, the thicker the film thickness of the separation film (C), the higher the effect of preventing damage and dents caused by foreign matter tends to be higher. By obtaining the film thickness of the separation film (C) and the optical film (A) The balance of this can more effectively improve the effect of preventing damage and dents caused by foreign objects. For example, a thickness ratio T _A T _C of the optical film thickness of the separation membrane (T _C / T _A), is preferably 0.4 or more, more preferably 0.5 or more, and more preferably 0.6 or more. The ratio (T _C /T _A ) is usually 4 or less.

The adhesive layer-attached optical film of the laminated separation film of the present invention includes an optical film (A) and a separation film (C) laminated on at least one side of the aforementioned optical film (A) via an adhesive layer (B), And if its structure can have the usual functions of an optical film, that is, its structure is not limited. The optical film is preferably a polarizer, a polarizer, a phase difference plate or a phase difference film, and particularly preferably a polarizer or a polarizer.

For example, when the configuration of a preferred embodiment of the present invention is described based on Figures 1 and 2, the optical film 1 with the adhesive layer of the laminated separation film shown in Figure 1 is composed of optical The film 10 and the separation film 30 laminated via the adhesive layer 20 on one side of this optical film are comprised. Furthermore, in the optical film 10, resin films 3 and 4 are laminated on both sides of the polarizer 20, and the area of the resin film 4 on the opposite side to the resin film having the adhesive layer 20 is not in contact with the polarizer 2层保护膜5。 Layer protection film 5. Furthermore, the adhesive layer-attached optical film 1 of the laminated separation film shown in FIG. 2 is composed of an optical film 10 and a separation film 30 laminated on one side of the optical film via an adhesive layer 20. In the film 10, resin films 3 and 4 are laminated on both sides of the polarizer 20, and a hard coat layer is layered on the area of the resin film 4 on the opposite side to the resin film having the adhesive layer 20 that is not in contact with the polarizer 2 6. Furthermore, a protective film 5 is laminated on the hard coat layer 6. In addition, the resin films 3 and 4 may be bonded to the polarizer 2 via an adhesive layer or an adhesive layer not shown.

The respective layers (members) constituting the "adhesive layer-attached optical film of the laminated separation film" of the present invention are not particularly limited, and can be appropriately determined according to the characteristics of the desired optical film and the like. Hereinafter, the preferred aspects of each constituent component of the "adhesive layer-attached optical film of the laminated separation film" of the present invention will be described in detail.

[1] Optical film (A) [1-1] Polarizing plate

In this specification, the so-called polarizing plate refers to a resin film or a resin layer layered on at least one area of the polarizing member. Polarizer refers to a film that absorbs linearly polarized light with a vibration surface parallel to its absorption axis and transmits linearly polarized light with a vibration surface perpendicular to its absorption axis (parallel to the transmission axis) For example, a film obtained by adsorbing and aligning a dichroic dye on a polyvinyl alcohol-based resin film can be used. Examples of dichroic dyes include iodine and dichroic organic dyes.

Polyvinyl alcohol-based resins are usually obtained by saponifying polyvinyl acetate-based resins. Polyvinyl acetate-based resins include, for example, polyvinyl acetate which is a homopolymer of vinyl acetate; it is composed of monomers copolymerizable with vinyl acetate (such as unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated Sulfonic acid, (meth)acrylamide having an ammonium group, etc.) and copolymers of vinyl acetate.

The degree of saponification of the polyvinyl alcohol-based resin is usually 85 to 100 mol%, preferably about 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and may be, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes. The average degree of polymerization of the polyvinyl alcohol-based resin is usually 1,000 to 10,000, preferably about 1,500 to 5,000. In addition, the average degree of polymerization of the polyvinyl alcohol-based resin can be determined in accordance with JIS K 6726.

Usually, what formed a polyvinyl alcohol-type resin into a film can be used as a raw material film of a polarizer. The polyvinyl alcohol resin can be formed into a film by a conventional method. The thickness of the raw material film is usually 1 to 150 μm, and in consideration of ease of stretching, etc., it is preferably 10 μm or more.

The polarizer is, for example, a step of uniaxially stretching a raw film, a step of dyeing the film with a dichroic dye to adsorb the dichroic dye, a step of treating the film with an aqueous solution of boric acid, and a step of washing the film, and finally Make it dry and make it. In the present invention, the thickness of the polarizer is usually 1 to 50 μm, and from the viewpoint of thinning the optical film, it is preferably 30 μm or less, more preferably 15 μm or less, and particularly preferably 10 μm or less.

The polarizer formed by adsorbing and aligning the dichroic dye on the polyvinyl alcohol-based resin film can be obtained by the following 1) method and also by the following 2) method: 1) Use A single film of a polyvinyl alcohol-based resin film is used as a raw material film, and the film is subjected to a uniaxial stretching treatment and a method of dyeing a dichroic dye; 2) coating a coating solution containing a polyvinyl alcohol-based resin on the base film ( Aqueous solution, etc.), dried to obtain a base film with a polyvinyl alcohol-based resin layer, and then stretched uniaxially together with the base film, and the stretched polyvinyl alcohol-based resin layer is subjected to dichroic dye A method of dyeing and then peeling and removing the substrate film. As the base film, a film made of the same thermoplastic resin as the thermoplastic resin capable of constituting the resin film described later can be used. Preferably, it is a film composed of the following resins: polyester resins such as polyethylene terephthalate, polycarbonate resins, cellulose resins such as triacetyl cellulose, norbornene resins Such as cyclic polyolefin resins, polystyrene resins, etc. When the method of 2) above is used, the production of a thin film polarizer can be made easy, for example, the production of a polarizer having a thickness of 7 μm or less can also be made easy.

The resin film may be, for example, a film composed of the following resins: a thermoplastic resin having light transmittance (preferably optically transparent), such as a chain polyolefin resin (polyethylene resin, polypropylene resin, etc.), Polyolefin resins such as cyclic polyolefin resins (norbornene resins, etc.); fiber resins (cellulose ester resins, etc.); polyester resins (polyethylene terephthalate, polyethylene naphthalate, etc.) Ethylene glycol, polybutylene terephthalate, etc.); polycarbonate resins (for example, polycarbonate derived from bisphenols such as 2,2-bis(4-hydroxyphenyl)propane, etc.); (A Base) acrylic resin; styrene resin; polyetheretherketone resin; polysulfide resin, or a mixture or copolymer of these. Among them, the resin film is preferably a film composed of cyclic polyolefin resin, polycarbonate resin, fiber resin, polyester resin, (meth)acrylic resin, etc., and particularly preferably fiber resin And a film composed of cyclic polyolefin-based resins.

Examples of the chain polyolefin resin include homopolymers of chain olefins such as polyethylene resins and polypropylene resins, or copolymers composed of two or more chain olefins.

Cyclic polyolefin resin is a resin containing norbornene, tetracyclododecane (alias: dimethanooctahydronaphthalene) or these derivatives as representative examples of cyclic olefins as polymerized units Collectively. Cyclic polyolefin resins include, for example, ring-opening (co)polymers of cyclic olefins and their hydrogenated products, addition polymers of cyclic olefins, cyclic olefins and chain olefins such as ethylene or propylene, or have Copolymers of vinyl aromatic compounds, and modified (co)polymers modified with unsaturated carboxylic acids or derivatives thereof. Among these, it is preferable to use a norbornene-based resin using a norbornene-based monomer such as a norbornene-based monomer and a polycyclic norbornene-based monomer as a cyclic olefin.

The cellulose resin is preferably a cellulose ester resin, that is, a partial or complete esterification of cellulose. Examples include acetate, propionate, butyrate, and mixed esters of cellulose. . Among these, more preferred are triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate.

The polyester resin is a resin other than the above-mentioned cellulose ester resin having an ester bond, and is generally composed of a polycondensate of a polycarboxylic acid or its derivative and a polyhydric alcohol. Polyester resins include, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and polytrimethylene terephthalate. , Polypropylene naphthalate, polycyclohexane dimethyl terephthalate, polycyclohexane dimethyl naphthalate, etc.

Polycarbonate resin is a polyester formed by carbonic acid and glycol or bisphenol. Among these, from the viewpoint of heat resistance, weather resistance, and acid resistance, an aromatic polycarbonate having diphenylalkane in the molecular chain is preferred. The polycarbonate includes, for example, 2,2-bis(4-hydroxyphenyl)propane (alias: bisphenol A), 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis( 4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)isobutane, 1,1-bis(4-hydroxyphenyl)ethane and other bisphenol-derived polycarbonates.

The (meth)acrylic resin that can constitute the resin film may be a polymer mainly composed of structural units derived from methacrylate (for example, containing 50% by weight or more thereof), and is preferably copolymerized with other copolymerization components. Into the copolymer. The (meth)acrylic resin may contain two or more types of structural units derived from methacrylate. _{Examples of the methacrylate include C 1} to C ₄ alkyl esters of methacrylic acid such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate.

As for the copolymerization component which can be copolymerized with methacrylate, an acrylate is mentioned, for example. _{The acrylate is preferably a C 1} to C ₈ alkyl ester of acrylic acid such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate. Specific examples of other copolymerization components include, for example, unsaturated carboxylic acids such as (meth)acrylic acid; aromatic vinyl compounds such as styrene, halogenated styrene, α-methylstyrene, and vinyl toluene; (methyl) ) Vinyl cyanides such as acrylonitrile; unsaturated carboxylic acid anhydrides such as maleic anhydride and methyl maleic anhydride; unsaturated carboxylic acid anhydrides such as phenyl maleimide and cyclohexyl maleimide Compounds other than acrylates having one polymerizable carbon-carbon double bond in the molecule, such as imines. Copolymerization components can be used alone or in combination of two or more kinds.

The (meth)acrylic resin may have a ring structure in the polymer main chain from the viewpoint of improving the durability of the film. The ring structure is preferably a heterocyclic structure such as a cyclic acid anhydride structure, a cyclic imine structure, and a lactone ring structure. Specific examples of the cyclic anhydride structure include glutaric anhydride structure, succinic anhydride structure, etc., specific examples of cyclic anhydride structure include glutaric imine structure, succinimide structure, etc., lactone ring structure Specific examples of is, for example, a butyrolactone ring structure, a valerolactone ring structure, and the like.

The (meth)acrylic resin may contain acrylic rubber particles from the viewpoints of film formability to the film, impact resistance of the film, and the like. The so-called acrylic rubber particles refer to particles in which an elastic polymer mainly composed of acrylate is regarded as an essential component. For example, a single-layer structure consisting essentially of the elastic polymer or an elastic polymer It is a one-layer multi-layer structure. Examples of the elastic polymer include, for example, a crosslinked elastic copolymer that contains alkyl acrylate as a main component and copolymerizes it with other vinyl monomers and crosslinkable monomers copolymerizable therewith. _{Examples of the alkyl acrylate that is the main component of the elastic polymer include C 1} to C ₈ alkyl acrylates of acrylic acid such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate. The carbon number of the alkyl group is preferably 4 or more.

Regarding other vinyl monomers copolymerizable with acrylates, for example, compounds having one polymerizable carbon-carbon double bond in the molecule, and more specifically, methacrylates such as methyl methacrylate. , Aromatic vinyl compounds such as styrene, vinyl cyanide such as (meth)acrylonitrile, etc. The crosslinkable monomer includes, for example, a crosslinkable compound having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, includes ethylene glycol di(meth)acrylate and butanediol (Meth)acrylates of polyols such as di(meth)acrylates, allyl (meth)acrylates and other (meth)acrylates, divinylbenzene, etc.

The content of the acrylic rubber particles is preferably 5 parts by mass or more, and more preferably 10 parts by mass or more with respect to 100 parts by mass of the (meth)acrylic resin. When the content of acrylic rubber particles is too large, the surface hardness of the film decreases, and when the film is surface-treated, the solvent resistance to the organic solvent in the surface treatment agent may decrease. Therefore, the content of the acrylic rubber particles is usually 80 parts by mass or less, preferably 60 parts by mass or less with respect to 100 parts by mass of the (meth)acrylic resin.

The resin film may contain additives commonly used in the technical field of the present invention. Examples of additives include ultraviolet absorbers, infrared absorbers, organic dyes, pigments, inorganic dyes, antioxidants, antistatic agents, surfactants, lubricants, dispersants, and heat stabilizers. Examples of ultraviolet absorbers include salicylate compounds, benzophenone compounds, benzotriazole compounds, triazine compounds, cyano (meth)acrylate compounds, nickel aluminum salts, and the like.

The resin film may be an unstretched film, or a film stretched uniaxially or biaxially. The resin film may be a protective film responsible for protecting the polarizer, or a protective film having an optical function like a retardation film described later. Furthermore, when the polarizing plate includes a plurality of resin films, the resin films may be the same or different films.

Moreover, the resin film may be provided with a hard coat layer, an anti-glare layer, an anti-reflection layer, a light diffusion layer, an antistatic layer, an antifouling layer, and a conductive layer on its outer surface (the surface opposite to the polarizer). (Coating layer). The thickness of the resin film is usually 1 to 70 μm, preferably 5 to 50 μm, and can be 30 μm or less.

The resin film can be attached to the polarizer through an adhesive layer or an adhesive layer. As the adhesive for forming the adhesive layer, a water-based adhesive or an active energy ray curable adhesive can be used.

Examples of water-based adhesives include commonly used water-based adhesives (for example, adhesives composed of polyvinyl alcohol-based resin aqueous solutions, water-based two-component urethane-based emulsified adhesives, aldehyde compounds, epoxy compounds, and melamine-based adhesives. Compounds, methylol compounds, isocyanate compounds, amine compounds, crosslinking agents such as polyvalent metal salts, etc.). Among these, an aqueous adhesive composed of a polyvinyl alcohol-based resin aqueous solution can be suitably used. Furthermore, when a water-based adhesive is used, after bonding the polarizer and the resin film, in order to remove the water contained in the water-based adhesive, it is preferable to perform a drying step. After the drying step, an aging step for aging at a temperature of about 20 to 45°C may be provided.

The above-mentioned active energy ray curable adhesive refers to an adhesive that is cured by irradiating active energy rays such as ultraviolet rays or electron rays, and examples include curable compositions containing polymerizable compounds and photopolymerization initiators, and photoreactive adhesives. The curable composition of a curable resin, a curable composition containing a binder resin and a photoreactive crosslinking agent, etc., are preferably an ultraviolet curable adhesive.

When an active energy ray curable adhesive is used, after bonding the polarizer and the resin film, a drying step is performed as needed, and then a curing step of curing the active energy ray curable adhesive by irradiating the active energy ray is performed. Although the light source of the active energy ray is not particularly limited, it is preferably ultraviolet light having a light emission distribution at a wavelength of 400 nm or less.

The method of bonding the polarizer and the resin film includes, for example, a method of performing surface activation treatments such as saponification treatment, corona treatment, and plasma treatment on the bonding surface of at least one of these. When bonding resin films on both sides of the polarizer, the adhesive for bonding the resin films may be the same type of adhesive or different types of adhesives.

For the polarizing plate, other films or layers may be laminated. As for specific examples, in addition to the retardation film described later, there are also brightening films, anti-glare films, anti-reflection films, diffuser films, light-concentrating films, adhesive layers, coating layers, and protective layers other than the adhesive layer (B).膜等。 Membrane and so on. The protective film is a film used for the purpose of protecting the surface of an optical film such as a polarizing plate from damage and contamination. The general rule is that the optical film with an adhesive layer is attached to, for example, a metal layer or a substrate and then peeled off. It.

The protective film is usually composed of a base film and an adhesive layer laminated on it. The base film can be made of thermoplastic resins (for example, polyolefin resins such as polyethylene resins and polypropylene resins; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polycarbonate resins). Resin; (meth)acrylic resin, etc.).

[1-2] Phase difference plate

In this specification, the term "phase difference plate" refers to a resin film or a resin layer layered on at least one area of the phase difference film. The retardation film contained in the retardation plate is an optical film that exhibits optical anisotropy. It can be a stretched film obtained by stretching a resin film composed of the following resin to about 1.01 to 6 times: in addition to being used as In addition to the thermoplastic resins exemplified above in the resin film, for example, polyvinyl alcohol-based resins, polyarylate-based resins, polyimide-based resins, polyether sulfide-based resins, and polyvinylidene fluoride/polymethyl fluoride resins can also be cited. Methyl acrylate resin, liquid crystal polyester resin, saponified ethylene-vinyl acetate copolymer, polyvinyl chloride resin, etc. Among these, a stretched film obtained by uniaxially stretching or biaxially stretching a polycarbonate resin film, a cyclic olefin resin film, a (meth)acrylic resin film, or a cellulose resin film is preferable. Moreover, in this specification, zero retardation film (zero retardation film) is also included in retardation film (but can be used as a protective film). In addition, films called uniaxial retardation films, wide viewing angle retardation films, low photoelasticity retardation films, and the like can also be suitably used as retardation films.

Called zero retardation film, retardation value R _e and R _th retardation value in the thickness direction are both within -15 to 15nm mean film plane. This retardation film is suitable for use in an IPS mode liquid crystal display device. R _e in-plane retardation value and the thickness direction retardation value R _th line are all preferably 10 to 10nm, more preferably 5 to 5nm. Here, the term plane retardation value R _e and the thickness direction retardation value R _th, the value means the wavelength of 590nm.

In-plane retardation and thickness direction retardation R _e and R _th value defined by the following formula _{based: R e = (n x -n} y) × d

R _th =[(n _x +n _y )/2-n _z ]×d where n _x is the refractive index in the slow axis direction (x-axis direction) in the _{film plane, and n y} is the fast axis in the film plane The refractive index in the direction (the y-axis direction perpendicular to the x-axis in the plane), n _z is the refractive index in the film thickness direction (the z-axis direction perpendicular to the film surface), and d is the thickness of the film.

Zero retardation films can be made of polyolefin resins such as cellulose resins, chain polyolefin resins and cyclic polyolefin resins, polyethylene terephthalate resins, or (meth)acrylic resins. Resin film made of resin, etc. In particular, since the retardation value is easy to control and easy to obtain, it is preferable to use a cellulose resin, a polyolefin resin, or a (meth)acrylic resin.

Furthermore, a film that expresses optical anisotropy by coating and alignment of a liquid crystal compound or a film that expresses optical anisotropy by coating an inorganic layered compound can also be used as a retardation film. Such retardation films are called temperature-compensated retardation films, and there are also films in which rod-shaped liquid crystals are oriented obliquely, sold under the trade name of "NH FILM" by JX Nippon Oil & Energy Co., Ltd. A film with oblique orientation of disc-shaped liquid crystal sold by Fuji Film Co., Ltd. under the brand name of "WV FILM", and a fully biaxially aligned type sold by Sumitomo Chemical Co., Ltd. under the brand name of "VAC FILM" Membrane, a biaxially oriented membrane sold by Sumitomo Chemical Co., Ltd. under the trade name "new VAC FILM", etc. Furthermore, the resin film laminated on at least one side of the retardation film may be, for example, the above-mentioned protective film.

[2] Adhesive layer (B)

The adhesive constituting the "adhesive layer (B) laminated on at least one side of the optical film (A) of the present invention (adhesive layer 20 in Fig. 1 and Fig. 2)" can be used without particular limitation. Known adhesives include, for example, adhesives having matrix polymers such as acrylic, rubber, urethane, silicone, and polyvinyl ether. Moreover, it may be an energy ray-curable adhesive, a thermosetting adhesive, or the like. Among these, it is suitable to be an adhesive using an acrylic resin with good transparency, adhesion, heavy workability, weather resistance, heat resistance, etc. as the matrix polymer. In a preferred embodiment of the present invention, the adhesive layer (B) is composed of an adhesive composition comprising (meth)acrylic resin (a), crosslinking agent (b), and silane compound (c) The reaction product is composed.

[2-1] (Meth) acrylic resin (a)

In the present invention, the (meth)acrylic resin (a) that can be included in the adhesive composition constituting the adhesive layer (B) is preferably derived from (A) represented by the following formula (I) A polymer (hereinafter also referred to as "(meth)acrylate polymer") having a structural unit of alkyl)acrylate (hereinafter also referred to as structural unit (I)) as the main component (for example, containing more than 50% by weight) :

(In the formula, R ¹⁰ represents a hydrogen atom or a methyl group, and R ²⁰ represents an alkyl group having 1 to 20 carbon atoms. The alkyl group may have any structure of linear, branched or cyclic. The hydrogen atom of the alkyl group It may be substituted by an alkoxy group having 1 to 10 carbon atoms).

In addition, in this specification, "(meth)acrylic acid" refers to acrylic acid or methacrylic acid, and "(meth)" such as (meth)acrylate has the same meaning.

The (meth)acrylate represented by formula (I) includes, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, N-hexyl acrylate, isohexyl acrylate, n-heptyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, n- and iso-nonyl acrylate, n-decyl acrylate, isodecyl acrylate, N-Dodecyl acrylate, cyclohexyl acrylate, isobornyl acrylate, stearyl acrylate, 3-butyl acrylate, etc. Examples of alkoxy-containing alkyl acrylates include 2-methoxyethyl acrylate, ethoxymethyl acrylate, and the like.

The (meth)acrylate polymer may contain two or more structural units (I). In addition, from the viewpoint of achieving both adhesiveness and durability, it is preferable to include _{structural units with a homopolymer having a glass transition temperature T g} of 0°C or higher, and a homopolymer having a glass transition temperature T _{g of} less than 0°C. The building blocks of copolymers. The structural unit whose glass transition temperature (T _g ) of the homopolymer is 0° C. or more includes, for example, methyl acrylate, cyclohexyl acrylate, isobornyl acrylate, etc. From the viewpoint of durability, it is preferable to include acrylic acid. Methyl or isobornyl acrylate. The structural unit of the homopolymer whose glass transition temperature T _{g is} less than 0°C includes, for example, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, and acrylic acid. N-hexyl acrylate, isohexyl acrylate, n-heptyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, n-nonyl acrylate, isononyl acrylate, n-decyl acrylate, isodecyl acrylate, Among them, n-dodecyl acrylate and the like, preferably include n-butyl acrylate or 2-ethylhexyl acrylate, and particularly preferably include n-butyl acrylate.

The (meth)acrylate polymer may contain structural units derived from other monomers other than the structural unit (I). The structural unit derived from other monomers may be one type or two or more types. Specific examples of other monomers that may be contained in the (meth)acrylate polymer are shown below.

1) Monomers with polar functional groups

The (meth)acrylate polymer may contain a structural unit derived from a monomer having a polar functional group. The monomer having a polar functional group includes, for example, (meth)acrylate having a polar functional group. The polar functional group includes, for example, a hydroxyl group, a carboxyl group, a substituted amino group, an unsubstituted amino group, and the like. Examples of the polar functional group include heterocyclic groups such as epoxy groups. Specific examples of the (meth)acrylate having such a polar functional group include: 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxy (meth)acrylate Butyl ester, 2-(2-hydroxyethoxy)ethyl (meth)acrylate, 2-chloro-2-hydroxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate , Diethylene glycol mono(meth)acrylate and other monomers with hydroxyl groups; acrylomorpholine, vinylcaprolactam, N-vinyl-2-pyrrolidone, vinylpyridine, (meth)acrylic acid Methyl tetrahydrofuran, methyl tetrahydrofuran acrylate modified by caprolactone, 3,4-epoxycyclohexyl methyl (meth)acrylate, glycidyl (meth)acrylate, 2,5-dihydrofuran, etc. Heterocyclic monomers; aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, etc. have substituted Or monomers with unsubstituted amine groups; monomers with carboxyl groups such as (meth)acrylic acid and carboxyethyl (meth)acrylate. Among them, a monomer having a hydroxyl group is preferred, and from the viewpoint of the reactivity of the (meth)acrylic resin (a) with a crosslinking agent, a (meth)acrylate having a hydroxyl group is more preferred.

The (meth)acrylate polymer may contain the above-mentioned other monomers having a polar functional group in total with the (meth)acrylate having a hydroxyl group. However, it prevents the separation film from being laminated on the outer surface of the adhesive layer. From the viewpoint of enhancing the peeling force, it is preferable that the monomer having an amine group is not substantially contained. The term "substantially not included" here means that it is 1.0 part by mass or less in 100 parts by mass of all the structural units constituting the (meth)acrylic resin (a). Furthermore, from the viewpoint of improving the corrosion resistance to transparent electrodes such as ITO, it is preferable that the monomer having a carboxyl group is not substantially contained. The term "substantially not included" here means that it is 2.0 parts by mass or less in 100 parts by mass of all the structural units constituting the (meth)acrylic resin (a).

The content of the structural unit derived from the monomer having a polar functional group in the (meth)acrylate polymer is preferably 20 parts by mass or less with respect to 100 parts by mass of all the structural units of the (meth)acrylate polymer, It is more preferably not less than 0.1 part by mass and not more than 20 parts by mass, still more preferably not less than 0.1 part by mass and not more than 10 parts by mass, particularly preferably not less than 0.5 part by mass and not more than 10 parts by mass.

2) Monomers with aromatic groups

The (meth)acrylate polymer may contain a structural unit derived from a monomer having an aromatic group. Monomers having an aromatic group include, for example, one (meth)acrylic acid group and one or more aromatic rings (such as benzene ring, naphthalene ring, etc.) in the molecule and having a phenyl group, a phenoxyethyl group, or Benzyl (meth)acrylate. By including these structural units, the white spot phenomenon of the polarizing plate during the durability test can be suppressed.

The (meth)acrylate having a phenoxyethyl group includes, for example, 2-phenoxyethyl (meth)acrylate, 2-(2-phenoxyethoxy)ethyl (meth)acrylate, (Meth)acrylic acid ethylene oxide modified nonylphenol ester, (meth)acrylate 2-(o-phenylphenoxy)ethyl, etc. The structural unit having a benzyl group includes, for example, benzyl acrylate. Among them, from the viewpoint of suppressing white spots, 2-phenoxyethyl (meth)acrylate and 2-(2-phenoxyethoxy)ethyl (meth)acrylate are preferred.

The content of the structural unit derived from the monomer having an aromatic group in the (meth)acrylate polymer is preferably 50 parts by mass or less with respect to 100 parts by mass of all the structural units of the (meth)acrylate polymer, It is more preferably 4 parts by mass or more and 50 parts by mass or less, and still more preferably 4 parts by mass or more and 25 parts by mass or less.

3) Acrylic amine monomer

The (meth)acrylate polymer may contain a structural unit derived from a monomer having an acrylamide group. The monomer having an acrylamide group includes, for example, N-methylol acrylamide, N-(2-hydroxyethyl) acrylamide, N-(3-hydroxypropyl) acrylamide, N-( 4-hydroxybutyl)acrylamide, N-(5-hydroxypentyl)acrylamide, N-(6-hydroxyhexyl)acrylamide, N,N-dimethylacrylamide, N,N- Diethylacrylamide, N-isopropylacrylamide, N-(3-dimethylaminopropyl)acrylamide, N-(1,1-dimethyl-3-oxobutane Yl) acrylamide, N-[2-(2-oxo-1-imidazolidinyl) ethyl] acrylamide, 2-propenylamino-2-methyl-1-propane sulfonic acid, N-(Methoxymethyl)acrylamide, N-(ethoxymethyl)acrylamide, N-(propoxymethyl)acrylamide, N-(1-methylethoxymethyl) Yl)acrylamide, N-(1-methylpropoxymethyl)acrylamide, N-(2-methylpropoxymethyl)acrylamide [alias: N-(isobutylmethyl)propylene Amide], N-(butoxymethyl)acrylamide, N-(1,1-dimethylethoxymethyl)acrylamide, N-(2-methoxyethyl)acrylamide Amine, N-(2-ethoxyethyl) acrylamide, N-(2-propoxyethyl) acrylamide, N-[2-(1-methylethoxy)ethyl] propylene Amide, N-[2-(1-methylpropoxy)ethyl]acrylamide, N-[2-(2-methylpropoxy)ethyl]acrylamide [alias: N-( Isobutoxyethyl)acrylamide], N-(2-butoxyethyl)acrylamide, N-[2-(1,1-dimethylethoxy)ethyl]acrylamide Wait. By including these structural units, the exudation of additives such as antistatic agents can be suppressed. Among them, it is preferable to use N-(methoxymethyl)acrylamide, N-(ethoxymethyl)acrylamide, N-(propoxymeth)acrylamide, N-(butoxy (Methyl)acrylamide, N-(2-methylpropoxymeth)acrylamide, etc.

Furthermore, structural units derived from other monomers other than structural unit (I) include, for example, structural units derived from styrene-based monomers, structural units derived from vinyl-based monomers, and structural units derived from multiple (methyl) groups in the molecule. Structural units of acryl-based monomers, etc.

Styrenic monomers, for example: styrene; such as methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl Alkyl styrenes such as styrene, butyl styrene, hexyl styrene, heptyl styrene, and octyl styrene; such as halogenated fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, and iodostyrene Styrene; Nitrostyrene; Acetylstyrene; Methoxystyrene; Divinylbenzene, etc.

Vinyl monomers include, for example, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate, and other fatty acid vinyl esters; vinyl chloride, vinyl bromide, etc. halogenated Ethylene; halogenated vinylenes such as chlorinated vinylene; nitrogen-containing heteroaromatic ethylenes such as vinyl pyridine, vinyl pyrrolidone, and vinyl carbazole; such as butadiene, isoprene, chloroprene and other conjugated dienes ; And unsaturated nitriles such as acrylonitrile and methacrylonitrile.

Monomers having plural (meth)acrylic acid groups in the molecule include, for example, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, Tripropylene glycol di(meth)acrylate and other monomers with 2 (meth)acrylic acid groups in the molecule; trimethylolpropane tri(meth)acrylate and other monomers have 3 (meth)acrylic acid in the molecule The monomer of the base and so on.

The weight average molecular weight (Mw) of the (meth)acrylic resin (a) is preferably 500,000 to 2.5 million. When the weight average molecular weight is more than 500,000, the durability of the adhesive layer under high humidity and heat environment can be improved. When the weight average molecular weight is 2.5 million or less, the handleability when applying the adhesive solution becomes better. The molecular weight distribution (Mw/Mn) represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is usually 2-10. The weight average molecular weight can be analyzed by gel permeation chromatography (GPC), which is a value converted to standard polystyrene.

When the (meth)acrylic resin (a) is dissolved in ethyl acetate to become a solution with a concentration of 20% by weight, its viscosity at 25°C is preferably 20 Pa‧s or less, more preferably 0.1 to 15 Pa‧s. The viscosity in such a range is beneficial to improve the durability of the adhesive layer-attached optical film and the optical laminate including the same, and is beneficial to the reworkability of the adhesive layer-attached optical film. The above viscosity can be measured with a Brookfield viscometer.

From the viewpoint of achieving both adhesiveness and durability, the glass transition temperature of the (meth)acrylic resin (a) is preferably -10°C to -60°C. Furthermore, the glass transition temperature can be measured by a differential scanning calorimeter (DSC).

The (meth)acrylic resin (a) can usually be produced by a conventional polymerization method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, and an emulsion polymerization method. In the production of (meth)acrylic resin (a), polymerization is usually carried out in the presence of a polymerization initiator. The amount of the polymerization initiator used is usually 0.001 to 5 parts by mass with respect to 100 parts by mass of the total of all monomers constituting the (meth)acrylic resin (a). The (meth)acrylic resin (a) can also be produced by a method of polymerization with active energy rays such as ultraviolet rays.

Examples of the polymerization initiator include thermal polymerization initiators and photopolymerization initiators. The photopolymerization initiator includes, for example, 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone and the like. Thermal polymerization initiators, for example: 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane Alkane-1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxy Valeronitrile), dimethyl-2,2'-azobis(2-methylpropionate), 2,2'-azobis(2-hydroxymethylpropionitrile) and other azo compounds; such as Lauryl peroxide, 3rd butyl peroxide, Benzyl peroxide, 3rd butyl peroxybenzoate, Cumene hydroperoxide, Diisopropyl peroxydicarbonate, Dipropylene peroxydicarbonate Peroxide, 3 butyl peroxyneodecanoate, 3 butyl peroxypivalate, peroxide (3,5,5-trimethylhexyl) and other organic peroxides; such as potassium persulfate, peroxy Inorganic peroxides such as ammonium sulfate and hydrogen peroxide. In addition, a redox-based initiator obtained by using a peroxide and a reducing agent in combination can also be used as a polymerization initiator.

The (meth)acrylic resin (a) is preferably produced by a solution polymerization method. Specifically, a desired monomer and an organic solvent are mixed, and a thermal polymerization initiator is added to the resulting solution in a nitrogen atmosphere. The obtained mixture is stirred at about 40 to 90°C (preferably about 60 to 80°C) for about 3 to 10 hours to obtain a (meth)acrylate polymer. In order to control the polymerization reaction, the monomer, the thermal polymerization initiator, or both may be added to the reaction system continuously or intermittently during the polymerization reaction, or may be added in a state of being dissolved in an organic solvent. Examples of organic solvents include: aromatic hydrocarbon solvents such as toluene and xylene; ester solvents such as ethyl acetate and butyl acetate; aliphatic alcohol solvents such as propanol and isopropanol; such as acetone, methyl ethyl ketone, Ketone solvents such as methyl isobutyl ketone.

The (meth)acrylic resin (a) may contain two or more (meth)acrylate polymers. Such (meth)acrylate polymers include, for example, those having the aforementioned (meth)acrylate-derived structural unit (I) as a main component and having a weight average molecular weight of a relatively low molecular weight in the range of 50,000 to 300,000 ( Meth)acrylate polymer.

[2-2] Crosslinking agent (b)

The adhesive composition forming the adhesive layer (B) preferably contains a crosslinking agent (b). The cross-linking agent (b) includes, for example, commonly used cross-linking agents (for example, isocyanate compounds, epoxy compounds, aziridine compounds, metal clamp compounds, peroxides, etc.), especially from adhesive compositions From the viewpoints of the pot life and the durability of the optical film with the adhesive layer, the crosslinking speed, etc., an isocyanate-based compound is preferred.

The isocyanate compound is preferably a compound having at least two isocyanate groups (-NCO) in the molecule, and examples thereof include aliphatic isocyanate compounds (for example, hexamethylene diisocyanate), and alicyclic isocyanate compounds (for example Isophorone diisocyanate), aromatic isocyanate compounds (e.g. tolylylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, naphthalene Diisocyanate, triphenylmethane triisocyanate, etc.). Furthermore, the crosslinking agent (b) may also be: adducts of polyol compounds of the aforementioned isocyanate compounds [for example, adducts of glycerol, trimethylolpropane, etc.], isocyanurate Compounds, biuret type compounds; amines formed by addition reaction with polyether polyols, polyester polyols, acrylic polyols, polybutadiene polyols, polyisoprene polyols, etc. Derivatives such as ester prepolymer type isocyanate compounds. The crosslinking agent (b) can be used alone or in combination of two or more kinds. Among these, from the viewpoint of durability, tolylylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, and these polyol compounds or these trimeric isocyanate compounds are preferred.

The ratio of the crosslinking agent (b) relative to 100 parts by mass of the (meth)acrylic resin (a) may be, for example, 0.01 to 10 parts by mass (for example, 0.05 to 5 parts by mass), preferably 0.1 to 3 parts by mass (For example, 0.1 to 2 parts by mass), more preferably 0.1 to 1 part by mass (for example, 0.1 to 0.8 parts by mass). When it is less than the upper limit value, it is advantageous for the improvement of durability (peel resistance), and when it is more than the lower limit value, it is advantageous for the improvement of foaming resistance and reworkability.

[2-3] Silane compound (c)

The adhesive composition contains a silane compound (c). Thereby, the adhesiveness of an adhesive layer and a glass substrate etc. can be improved. Two or more types of silane compounds (c) can also be used.

The silane compound (c) includes, for example, vinyl trimethoxy silane, vinyl triethoxy silane, vinyl tris(2-methoxyethoxy) silane, 3-glycidoxy propyl trimethoxy 3-glycidoxy propyl triethoxy silane, 3-glycidoxy propyl methyl dimethoxy silane, 3-glycidoxy propyl ethoxy dimethyl Silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methylpropene Glyoxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, etc.

The silane compound (c) may include polysiloxane oligomer type. Specific examples of polysiloxane oligomers, when expressed in the form of a combination of monomers, are as follows: 3-mercaptopropyltrimethoxysilane-tetramethoxysilane oligomer, 3-mercapto Propyl trimethoxysilane-tetraethoxysilane oligomer, 3-mercaptopropyltriethoxysilane-tetramethoxysilane oligomer, 3-mercaptopropyltriethoxysilane-tetraethoxy Oligomers containing mercaptopropyl groups such as methyl silane oligomers; mercaptomethyl trimethoxy silane-tetramethoxy silane oligomers, mercapto methyl trimethoxy silane-tetraethoxy silane oligomers, mercapto groups Methyltriethoxysilane-tetramethoxysilane oligomer, mercaptomethyltriethoxysilane-tetraethoxysilane oligomer and other oligomers containing mercaptomethyl groups; 3-epoxypropoxy 3-glycidoxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-glycidoxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-glycidoxypropyltriethoxy Silane-tetramethoxysilane copolymer, 3-glycidoxypropyltriethoxysilane-tetraethoxysilane copolymer, 3-glycidoxypropylmethyldimethoxysilane -Tetramethoxysilane copolymer, 3-glycidoxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-glycidoxypropylmethyldiethoxysilane -Tetramethoxysilane copolymer, 3-glycidoxypropylmethyldiethoxysilane-tetraethoxysilane copolymer and other copolymers containing 3-glycidoxypropyl; 3- Methacryloxypropyltrimethoxysilane-tetramethoxysilane oligomer, 3-methacryloxypropyltrimethoxysilane-tetraethoxysilane oligomer, 3-methyl Acrylicoxypropyl triethoxysilane-tetramethoxysilane oligomer, 3-methacryloxypropyltriethoxysilane-tetraethoxysilane oligomer, 3-methyl Acrylicoxypropylmethyldimethoxysilane-tetramethoxysilane oligomer, 3-methacryloxypropylmethyldimethoxysilane-tetraethoxysilane oligomer, 3-methacryloxypropylmethyldiethoxysilane-tetramethoxysilane oligomer, 3-methacryloxypropylmethyldiethoxysilane-tetraethoxysilane Oligomers and other oligomers containing methacryloxypropyl; 3-propyleneoxypropyltrimethoxysilane-tetramethoxysilane oligomer, 3-propyleneoxypropyltrimethoxy Silyl-tetraethoxysilane oligomer, 3-propenyloxypropyl triethoxysilane-tetramethoxysilane oligomer, 3-propenyloxypropyl triethoxysilane-tetra Methoxysilane oligomer, 3-propenyloxypropylmethyldimethoxysilane-tetramethoxysilane oligomer, 3-propenyloxypropylmethyldimethoxysilane-tetra Ethoxysilane oligomer, 3-propenyloxypropylmethyldiethoxysilane-tetramethoxysilane oligomer, 3-propenyloxypropylmethyldiethoxysilane-tetra Ethoxysilane oligomers and other oligomers containing acrylic oxypropyl groups; vinyl trimethoxysilane-tetramethoxysilane oligomers, vinyl trimethoxysilane-tetraethoxysilane oligomers Compounds, vinyl triethoxysilane-tetramethoxysilane Oligomer, vinyl triethoxy silane-tetraethoxy silane oligomer, vinyl methyl dimethoxy silane-tetramethoxy silane oligomer, vinyl methyl dimethoxy silane- Tetraethoxysilane oligomer, vinylmethyldiethoxysilane-tetramethoxysilane oligomer, vinylmethyldiethoxysilane-tetraethoxysilane oligomer, etc. contain vinyl groups The oligomer; 3-aminopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-aminopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-aminopropyltri Ethoxysilane-tetramethoxysilane copolymer, 3-aminopropyltriethoxysilane-tetraethoxysilane copolymer, 3-aminopropylmethyldimethoxysilane-tetramethoxysilane -Based silane copolymer, 3-aminopropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-aminopropylmethyldiethoxysilane-tetramethoxysilane copolymer, 3 -Aminopropylmethyldiethoxysilane-tetraethoxysilane copolymer and other amine group-containing copolymers.

The content of the silane compound (c) in the adhesive composition, relative to 100 parts by mass of the (meth)acrylic resin (a), is usually 0.01 to 10 parts by mass, preferably 0.03 to 5 parts by mass, and more preferably 0.05 to 2 parts by mass, and more preferably 0.1 to 1 part by mass. When the content of the silane compound (c) is 0.01 parts by mass or more, the effect of improving the adhesion between the adhesive layer and the substrate (glass or transparent electrode) is easily obtained. Furthermore, when the content is 10 parts by mass or less, the silane compound (c) which can be suppressed oozes from the adhesive layer.

[2-4] Antistatic agent

The adhesive composition forming the adhesive layer (B) may further include an antistatic agent. By containing the antistatic agent, the antistatic property of the optical film with the adhesive layer of the laminated separation film can be improved. For example, it is possible to suppress defects caused by static electricity generated when the separation film or protective film is peeled off.

Examples of antistatic agents include those commonly used, and ionic antistatic agents are preferred. Examples of the cationic component constituting the ionic antistatic agent include organic cations and inorganic cations. Examples of organic cations include pyridinium cations, imidazolium cations, ammonium cations, pyrrolidinium cations, piperidinium cations, sulfonium cations, and phosphonium cations. Examples of inorganic cations include alkali metal cations such as lithium cation, potassium cation, sodium cation, and isocation; alkaline earth metal cations such as magnesium cation and calcium cation. The anion component constituting the ionic antistatic agent may be either organic anion or inorganic anion, but from the viewpoint of good antistatic function, an anion component containing a fluorine atom is preferred. An anionic component containing a fluorine atom includes, for example hexafluorophosphate anion (PF ₆ ^-), bis (trifluoromethane sulfonic acyl) acyl imide anion _{[(CF 3 SO 2) 2} N -], bis (fluorosulfonyl acyl) acyl imide anion ^{_{[(FSO 2) 2 N -}} ], tetrakis (pentafluorophenyl) borate anion _{[(C 6 F 5) 4} B -] and the like. These antistatic agents can be used alone or in combination of two or more kinds.

From the viewpoint of the good stability of the antistatic function of the adhesive composition over time, it is preferable to use an ionic antistatic agent that is solid at room temperature. The ratio of the antistatic agent relative to 100 parts by mass of the (meth)acrylic resin (a) is, for example, 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass, and more preferably 0.5 to 4 parts by mass.

[2-5] Other ingredients

The adhesive composition forming the adhesive layer (B) may contain one or more solvents, crosslinking catalysts, ultraviolet absorbers, weather stabilizers, tackifiers, plasticizers, softeners, dyes, Additives such as pigments, inorganic fillers, light-scattering particles, rust inhibitors, etc. In addition, an ultraviolet curable compound is formulated in the adhesive composition, and after the adhesive layer is formed, it is irradiated with ultraviolet rays to harden it, which is useful for forming a harder adhesive layer.

The thickness of the adhesive layer is usually 2 to 40 μm. From the viewpoint of durability and heavy workability of the optical film of the adhesive layer of the laminated separation film, it is preferably 5 to 30 μm, more preferably 10 to 25 μm . When it is less than the upper limit value, the reworkability of the optical film via the adhesive layer of the laminated separation film becomes better, and when it is more than the lower limit value, the durability becomes better.

Regarding the storage elastic modulus of the adhesive layer (B), the storage elastic modulus G'at 25°C is preferably 0.4 MPa or less, more preferably 0.3 MPa or less, and preferably 0.01 MPa or less. When it is 0.4 MPa or less, the stress relaxation properties of the adhesive become better, and the upward warpage (liquid crystal cell bending) of the liquid crystal panel caused by the shrinkage of the polarizing plate can be alleviated. On the other hand, when the storage elastic modulus G'becomes low (for example, 0.4 MPa or less), dents caused by foreign matter tend to be easily generated. However, as long as the film thickness of the separation membrane (C) is controlled according to the present invention, Even when an adhesive layer with a low storage elastic modulus is used, it can also provide an optical film with an adhesive layer attached to a laminated separation film with a good dent prevention effect.

The storage elastic modulus G'of the adhesive layer (B) at 25°C can be measured, for example, by the method described in the examples.

The storage elastic modulus G'of the adhesive layer (B) can be determined by, for example, the formulation of the adhesive composition ((meth)acrylic resin, crosslinking agent, multifunctional active energy) that constitutes the adhesive layer (B) The type/amount of the linear hardening compound) to control.

[3] Separation membrane (C)

The separation film (C) constituting the "adhesive layer-attached optical film of the laminated separation film" of the present invention preferably has a surface hardness of 15 or more in Vickers hardness. When the Vickers hardness is 15 or more, the separation membrane (C) has high surface hardness, and even if the surface is pressed with foreign matter attached to the surface, it is not easy to produce dents, which will prevent damage and dents caused by foreign matter in the optical film. The prevention effect is good. In the present invention, the Vickers hardness of the surface of the separation membrane (C) is preferably 15 or more, more preferably 17 or more, and particularly preferably 19 or more. When the Vickers hardness of the separation membrane (C) is high, since the separation membrane (C) becomes easy to be broken, it is usually 200 or less, preferably 150 or less. In addition, the Vickers hardness can be measured according to the method described in the Examples, for example.

The surface hardness of the separation membrane (C) can be controlled to a desired range by, for example, the selection of the plastic film constituting the separation membrane. Specifically, for example, increasing the stretching ratio during film formation to increase the strength of the film, or slowly cooling during film formation to increase the crystal grain size, or increasing the molecular weight of the resin used, etc. It can increase the surface hardness.

The separation film (C) constituting the "adhesive layer-attached optical film of the laminated separation film" of the present invention preferably has a bending stiffness of 1 mg or more. When the bending stiffness is greater than or equal to the aforementioned value, curling of the optical film can be suppressed. In the present invention, the aforementioned bending stiffness of the separation membrane is more preferably 1.5 mg or more. The upper limit of the flexural rigidity of the separation membrane (C) is generally 100 mg or less, preferably 50 mg or less, and more preferably 30 mg or less because the separation membrane can be easily peeled off when the separation membrane is peeled off. In addition, the aforementioned bending stiffness is a value measured according to the method described in the examples.

The bending rigidity of the separation membrane (C) can be controlled to a desired range by, for example, the thickness of the plastic film constituting the separation membrane and the film forming conditions (especially the stretching conditions). Specifically, for example, by increasing the thickness of the substrate or increasing the tensile elastic modulus of the substrate, the bending stiffness can be increased.

In the present invention, the separation membrane (C) is preferably composed of a plastic film and a release layer. Examples of the plastic film include polyester films such as polyethylene terephthalate films, polybutylene terephthalate films, and polyethylene naphthalate films, and polyolefin films such as polypropylene films. Among them, from the viewpoint of optical properties and quality, a polyethylene terephthalate film is preferred. Furthermore, because of its good dimensional stability, it is preferably a biaxially stretched polyethylene terephthalate film. membrane. In addition, the release layer can be formed of, for example, a composition for forming a release layer. The main component (resin) of the composition for forming a release layer is not particularly limited, and examples include silicone resin, alkyd resin, and acrylic resin. And long-chain alkyl resins, etc. Among them, silicone resin is preferred.

The silicone resin may be, for example, a silicone resin having dimethylpolysiloxane as a basic skeleton. In addition, silicone resins include addition reaction type, condensation reaction type, ultraviolet curing type, electron beam curing type, and the like. Among them, the addition reaction type silicone resin has the advantages of "high reactivity and good productivity, and when compared with the condensation reaction type, the change in peel force after manufacture is small, and there is no curing shrinkage" and other advantages, so it is Better.

Specific examples of the above-mentioned addition reaction type silicone resin include, for example, those having two or more vinyl groups, allyl groups, propenyl groups, hexenyl groups, etc., having 2 to 10 carbon atoms at the end and/or side chain of the molecule. Alkenyl-based organopolysiloxanes, etc. When using such an addition reaction type silicone resin, it is preferable to use a crosslinking agent and a catalyst in combination.

The above-mentioned crosslinking agent includes, for example, an organopolysiloxane having at least two hydrogen atoms bonded to a silicon atom in one molecule, and specifically, includes, for example, a dimethylhydrosiloxy end-blocked dimethyl group. Silicone-methylhydrosiloxane copolymer, trimethylsiloxy end-blocked dimethylsiloxane-methylhydrosiloxane copolymer, trimethylsiloxy end-blocked methyl hydrogen Polysiloxane, poly(hydrosilsesquioxane), etc.

The above-mentioned catalysts include, for example, particulate platinum, particulate platinum adsorbed on a carbon powder carrier, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefin complexes of chloroplatinic acid, palladium, rhodium And other platinum metal compounds. By using such a catalyst, the curing reaction of the composition for forming a release layer can be performed more efficiently.

When silicone resin is used in the composition for forming a release layer, it is preferable to add a release regulator such as MQ resin.

Furthermore, in the composition for forming a release layer, additives may be appropriately blended. Examples of additives include catalysts, dyes, and dispersants. In addition, in order to make the viscosity at the time of coating into an appropriate range in the composition for peeling layer formation, you may contain a dispersion medium or a solvent suitably.

Examples of the dispersion medium or solvent include aromatic hydrocarbons such as toluene, fatty acid esters such as ethyl acetate, ketones such as methyl ethyl ketone (MEK), and organic solvents such as aliphatic hydrocarbons such as hexane and heptane.

The separation membrane (C) can be produced by, for example, coating a composition for forming a release layer diluted in a solvent on one side of a plastic film by the following method. Examples include gravure coating, bar coating, spray coating, spin coating, air knife coating, roller coating, knife coating, gete roll coating, and die Coating method, etc. Among them, the gravure coating method and the bar coating method are preferred, and the gravure coating method is more preferred.

In addition, the heating and drying method of the composition for forming a peeling layer includes, for example, a method of thermal drying in a hot-air drying oven or the like. The drying temperature is, for example, 50°C or more and 150°C or less. Furthermore, the drying time is preferably 10 seconds to 5 minutes, for example.

The thickness of the separation film (C) can be controlled by the thickness of the plastic film and the thickness of the release layer. Among them, the thickness of the plastic film is the main one, which can be controlled by selecting a polyester film with a target thickness. The thickness of the plastic film is preferably 45 μm or more, more preferably 47 μm or more, and still more preferably 50 μm or more. Although the upper limit of the film thickness of the plastic film is not particularly limited, it is usually 200 μm or less. From the viewpoint of facilitating peeling when peeling the separation film, for example, it is preferably 150 μm or less, and more preferably 100 μm or less. The thickness of the release layer (when dried) is preferably 40 to 300 nm, more preferably 50 to 200 nm, and particularly preferably 80 to 150 nm. By making the thickness of the peeling layer 40 nm or more, uneven peeling force due to variations in the coating amount can be suppressed, and by making it 300 nm or less, blocking can be suppressed.

[4] The composition and manufacturing method of the adhesive layer-attached optical film of the laminated separation film

For example, as shown in Figure 1, the adhesive layer-attached optical film 1 of the laminated separation film includes an optical film 10 and an adhesive layer 20 laminated on at least one side of the optical film 10, and on the adhesive layer 20 The outer surface area of the layer separation membrane 30. The adhesive layer 20 is layered on a single area of the optical film 10. When laminating the adhesive layer 20 on the surface of the optical film 10, it is preferable to form a primer layer on the bonding surface of the optical film 10 and/or the bonding surface of the adhesive layer 20, or to perform surface activation treatment (for example, Plasma treatment, corona treatment, etc.), especially the best system to implement corona treatment.

An antistatic layer may be additionally provided between the optical film 10 and the adhesive layer 20. As for the antistatic layer, you can use: silicon-based materials such as polysiloxane; inorganic metal-based materials such as tin-doped indium oxide and tin-doped antimony oxide; polythiophene, polystyrene sulfonic acid, polyaniline, etc. Organic polymer materials.

The adhesive layer-attached optical film 1 of the laminated separation film can be obtained, for example, by the following process: dissolving or dispersing each component of the adhesive composition forming the adhesive layer (B) in a solvent to produce The adhesive composition of the solvent is then applied to the release surface of the release film 30 and dried to form an adhesive layer 20, which is laminated (transferred) on the surface of the optical film 10 .

The adhesive layer-attached optical film of the laminated separation film of the present invention preferably has a surface hardness of 15 or more in Vickers hardness. When the Vickers hardness is 15 or more, the optical film with the adhesive layer has high surface hardness, and even if the surface is pressed with foreign matter attached to the surface, it is not easy to produce dents, which will prevent damage and dents caused by foreign matter in the optical film. The effect of preventing scars is good. In the present invention, the Vickers hardness of the surface of the optical film with the adhesive layer of the laminated separation film is more preferably 17 or more, and still more preferably 19 or more. Regarding the upper limit of the Vickers hardness of the optical film with the adhesive layer of the laminated separation film, if the Vickers hardness is high, the optical film with the adhesive layer of the laminated separation film will be easily broken, so it is usually 200 or less , Preferably 150 or less. In addition, the Vickers hardness can be measured according to the method described in the Examples, for example.

The surface hardness of the optical film with the adhesive layer of the laminated separation film can be controlled to a desired range by, for example, the selection of the plastic film constituting the separation film. Specifically, for example, increasing the stretching ratio during film formation to increase the strength of the film, or slowly cooling during film formation to increase the crystal grain size, or increasing the molecular weight of the resin used, etc. It can increase the surface hardness.

[Example]

Hereinafter, examples and comparative examples are shown to explain the present invention more specifically, but the present invention is not limited to these examples. Below, the usage amount, parts and% of the content are shown, and unless otherwise noted, it is the quality standard.

1. Separation membrane (1) Production of separation membrane

(i) Preparation of composition for forming peeling layer

Combine organopolysiloxanes with vinyl groups, organopolysiloxanes with hydrosilyl groups, and polysiloxane resin solutions containing heavy release additives (manufactured by Toray Dow Corning, trade name: BY24-571, solid Parts (30% by mass) in terms of solid content, converted to 30 parts by mass, and diluted and mixed with a solvent of toluene/MEK=1/1 so that the solid content concentration becomes 1.0% by mass. To this solution, 2 parts by mass of a platinum-based catalyst (manufactured by Toray Dow Corning Corporation, trade name: SRX-212, solid content 100% by mass) was added to prepare a composition for forming a peeling layer.

(ii) Production of separation membrane 1

A biaxially stretched polyethylene terephthalate (PET) film A (PET50T-193 manufactured by Mitsubishi Plastics Corporation) having a thickness of 50 μm, an end azimuth angle of 8 degrees, and a haze of 5% was prepared. Then, on one side of the biaxially stretched PET film A, the composition for forming a peeling layer obtained above was coated with a bar coater to a thickness of 0.1 μm after drying, and dried at 120°C for 1 minute to form a peeling layer. Separation membrane 1.

(iii) Production of separation membrane 2

A biaxially stretched polyethylene terephthalate (PET) film B (PET38R-64 manufactured by Toray Corporation) having a thickness of 38 µm, an end azimuth angle of 6 degrees, and a haze of 10% was prepared. Then, on one side of the biaxially stretched PET film B, the above-obtained release layer forming composition was coated with a bar coater to a thickness of 0.1 μm after drying, and dried at 120°C for 1 minute to form a release layer to obtain Separation membrane 2.

(2) Determination of the physical properties of the separation membrane

(i) Surface hardness

After the separation membrane 1 and the separation membrane 2 produced above were cut into a size of 40 mm × 40 mm, respectively, the release treatment surface (peeling layer) of the separation membrane was bonded to 40 mm × 40 mm glass via an adhesive layer with a film thickness of 20 μm. Then, the evaluation sample bonded to the glass was used in an environment of 23°C and 55% using an ultra-micro hardness tester (FISCHERSCOPE HM2000: manufactured by Fischer Instruments Co., Ltd.) with a 0.1N/5s addition After applying a load at the compression rate, it was held for 5 seconds while maintaining a load of 0.1 N, and the Vickers hardness was measured. The results are shown in Table 1.

(ii) Bending stiffness

<Measurement Preparation>

After the separation membrane 1 and the separation membrane 2 produced above were cut into test pieces with a size of 25.4mm×25.4mm, one end of the test piece was installed on a Gurley tester (Gurley stiffness tester (electric type) 2094-M: A chuck for a movable arm manufactured by Kumagai Riki Kogyo. Align the 1 inch (25.4mm) position of the scale of the movable arm A and fix the chuck so that the test piece moves to a position away from the apex of the pendulum B first. Then, attach a 5g weight to the position of the load mounting hole a (1 inch) below the fulcrum of the pendulum B to make it a vertical state without vibration.

<Measurement operation>

Move the movable arm to the right or left at a constant speed at a speed of 2 times per minute. The lower part of the test piece touches the pendulum B, reads the scale R when leaving the pendulum B, and applies the following conversion formula to calculate the bending stiffness. The results are shown in Table 1.

S=((aWa+bWb+cWc)/5)×(l ² /b)×11.1×R (mg)

S: Bending stiffness (mg)

a, b, c: the distance between the load mounting hole and the fulcrum of the pendulum (inches)

Wa, Wb, Wc: the mass of the weight installed in the load mounting hole

l: Full length of test piece -1/2"(inch)

b: the width of the test piece (inches)

R: Reading value of scale

2. Production of optical film and adhesive layer-attached optical film of laminated separation film (1) Preparation of (meth)acrylic resin A for adhesive layer

Put 87.5 parts by mass of n-butyl acrylate, 5 parts by mass of methyl acrylate, and 5 parts by mass of 2-phenylethyl acrylate in a reaction vessel equipped with a stirrer, a thermometer, a reflux cooler, a dripping device, and a nitrogen introduction tube. 2.5 parts by mass of 2-hydroxyethyl acrylate, 200 parts by mass of ethyl acetate, and 0.08 parts by mass of 2,2'-azobisisobutyronitrile, and the air in the reaction vessel was replaced with nitrogen. The reaction solution was heated to 60° C. while stirring in this nitrogen atmosphere, and after the reaction was allowed to react for 16 hours, it was cooled to room temperature. Here, the molecular weight of a part of the obtained solution was measured by the method mentioned later, and it was confirmed that the (meth)acrylate polymer with a weight average molecular weight of 2 million was produced.

The weight average molecular weight (Mw) of the (meth)acrylate polymer is measured using a gel permeation chromatograph (GPC) and converted to the weight average molecular weight of polystyrene under the following conditions.

[Measurement conditions]

‧GPC measuring device: HLC-8020 manufactured by Tosoh

‧GPC column (through the following sequence): manufactured by Tosoh

TSK guard column HXL-H

TSK gel GMHXL(x2)

TSk gel G2000HXL

‧Measuring solvent: Tetrahydrofuran

‧Measuring temperature: 40℃

(2) Making the adhesive layer

(a) Preparation of adhesive composition (A)

100 parts by mass of the (meth)acrylate polymer obtained in the above step (1) (converted value of solid content; the same below), as an isocyanate-based crosslinking agent (B) modified with trimethylolpropane Tolyl diisocyanate (manufactured by Mitsui Takeda Chemical Co., Ltd., trade name "TAKENATE D-110N") 0.20 parts by mass, a combination of 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane as the silane coupling agent (C) 0.30 parts by mass of the co-condensate (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "X41-1810") was mixed, fully stirred, and diluted with ethyl acetate to obtain a coating solution of the adhesive composition (A).

(b1) Production of adhesive layer 1 (adhesive sheet 1)

On the release treatment surface (peeling surface layer) of the separation membrane 1 obtained above, the adhesive composition (A) prepared in (a) above was coated by an applicator so that the thickness after drying became 20 μm, and then After drying at 100°C for 1 minute, an adhesive layer 1 was obtained as an adhesive sheet 1.

(b2) Production of adhesive layer 2 (adhesive sheet 2)

Except that the separation membrane 2 obtained above is used instead of the separation membrane 1, the remaining operation is the same as the production of the adhesive layer 1 to obtain the adhesive layer 2 as the adhesive sheet 2.

(3) Production of optical film with adhesive layer through laminated separation film (I) Example 1: Optical film A1 with adhesive layer through laminated separation film

(i) Modulation of polarizing film (polarizer) A

A polyvinyl alcohol film ("Kuraray Poval Film VF-PS#7500", manufactured by Kuraray Co., Ltd.) with an average degree of polymerization of about 2400, a degree of saponification of 99.9 mol%, and a thickness of 75 μm is immersed in pure water at 37°C After that, it was immersed in an aqueous solution containing iodine and potassium iodide (iodine/potassium iodide/water (weight ratio)=0.04/1.5/100) at 30°C. Then, it was immersed in an aqueous solution containing potassium iodide and boric acid (potassium iodide/boric acid/water (weight ratio)=12/3.6/100) at 56.5°C. After the film was washed with pure water at 10°C, it was dried at 85°C to obtain a polarizing film A with a thickness of about 28 μm in which iodine was adsorbed and aligned with polyvinyl alcohol. The extension is mainly carried out in the steps of iodine dyeing and boric acid treatment, and the overall extension magnification is 5.3 times.

(ii) Modulation of optical film A

On one side of the obtained polarizing film A, a transparent protective film ("KC4UYW", Ke Nika Minolta Optical Co., Ltd.), and a 23μm-thick cyclic olefin resin film ("ZF14-023", manufactured by ZEON Co., Ltd.) was laminated on the opposite side of the transparent protective film to produce optical Film A (polarizing plate). The thickness of the optical film A was about 91 μm.

(iii) Production of optical film A1 (polarizing plate) with adhesive layer through laminated separation film

With respect to the surface of the obtained optical film A on which the cyclic olefin resin film is bonded, the surface of the adhesive sheet 1 produced in (b1) above and the separation film 1 on the opposite side (adhesive layer) After bonding, it was aged for 7 days under the conditions of a temperature of 23° C. and a relative humidity of 65% to obtain an optical film A1 (polarizing plate) having an adhesive layer of a laminated separation film having a layer composition shown in Table 2. The surface hardness (Vickers hardness) of the adhesive layer-attached optical film A1 of this laminated separation film was 20.4.

(II) Comparative example 1: Optical film A2 with adhesive layer through laminated separation film

Except that the adhesive sheet 2 produced in (b2) above is used instead of the adhesive sheet 1, the rest is the same as the production of the optical film A1 of the adhesive layer of the laminated separation film, and the layer structure shown in Table 2 is obtained. The optical film A2 with the adhesive layer of the laminated separation film. The surface hardness (Vickers hardness) of the adhesive layer-attached optical film A2 of this laminated separation film was 13.5.

(III) Example 2: Optical film B1 with adhesive layer through laminated separation film

(i) Modulation of polarizing film (polarizer) B

After immersing a polyvinyl alcohol film ("Kuraray Poval Film VF-PE#3000", manufactured by Kuraray Corporation) with an average degree of polymerization of about 2400, a degree of saponification of 99.9 mol%, and a thickness of 30 μm in pure water at 37°C, It was immersed in an aqueous solution containing iodine and potassium iodide (iodine/potassium iodide/water (weight ratio)=0.04/1.5/100) at 30°C. Then, it was immersed in an aqueous solution containing potassium iodide and boric acid (potassium iodide/boric acid/water (weight ratio)=12/3.6/100) at 56.5°C. After the film was washed with pure water at 10°C, it was dried at 85°C to obtain a polarizing film B with a thickness of about 12 μm in which iodine was adsorbed and aligned with polyvinyl alcohol. The extension is mainly carried out in the steps of iodine dyeing and boric acid treatment, and the overall extension magnification is 5.3 times.

(ii) Modulation of optical film B

On one side of the obtained polarizing film B, a transparent protective film ( "25KCHCN-TC", manufactured by Toppan Printing Co., Ltd.), and a 23μm-thick cyclic olefin resin film ("ZF14-023", manufactured by ZEON Co., Ltd.) is laminated on the opposite side of the transparent protective film. , Production of optical film B (polarizing plate). The thickness of the optical film B is about 67 μm.

(iii) Production of optical film B1 (polarizing plate) with adhesive layer through the laminated separation film

With respect to the surface of the obtained optical film B on which the cyclic olefin resin film is bonded, the surface of the adhesive sheet 1 produced in (b) above and the separation film 1 on the opposite side (adhesive layer) is applied by a laminator After bonding, it was aged for 7 days under the conditions of a temperature of 23° C. and a relative humidity of 65% to obtain an optical film B1 (polarizing plate) having an adhesive layer of a laminated separation film having a layer composition shown in Table 2. The surface hardness (Vickers hardness) of the adhesive layer-attached optical film B1 of this laminated separation film was 18.7.

(IV) Comparative Example 2: Optical film B2 with adhesive layer through the laminated separation film

Except that the adhesive sheet 2 produced in (b2) above is used instead of the adhesive sheet 1, the rest is the same as the production of the optical film B1 with the adhesive layer of the laminated separation film, and the layer structure shown in Table 2 is obtained. The optical film B2 with the adhesive layer of the laminated separation film. The surface hardness (Vickers hardness) of the adhesive layer-attached optical film B2 of this laminated separation film was 12.7.

(V) Reference example 1: Optical film C1 with adhesive layer through laminated separation film

(i) Modulation of polarizing film (polarizer) C

After immersing a polyvinyl alcohol film ("Kuraray Poval Film VF-PS#7500", manufactured by Kuraray) with an average degree of polymerization of about 2400, a degree of saponification of 99.9 mol%, and a thickness of 75 μm in pure water at 37°C, It was immersed in an aqueous solution containing iodine and potassium iodide (iodine/potassium iodide/water (weight ratio)=0.04/1.5/100) at 30°C. Then, it was immersed in an aqueous solution containing potassium iodide and boric acid (potassium iodide/boric acid/water (weight ratio)=12/3.6/100) at 56.5°C. After the film was washed with pure water at 10°C, it was dried at 85°C to obtain a polarizing film C having a thickness of about 28 μm in which iodine was adsorbed and aligned with polyvinyl alcohol. The extension is mainly carried out in the steps of iodine dyeing and boric acid treatment, and the overall extension magnification is 5.3 times.

(ii) Modulation of optical film C

On one side of the obtained polarizing film C, a transparent protective film ("KC6UAW", Ke Nika Minolta Optical Co., Ltd.), and a 50μm thick cyclic olefin resin film ("ZB12-050135", manufactured by ZEON Co., Ltd.) is laminated on the opposite side of the transparent protective film to produce optical Film C (polarizing plate). The thickness of the optical film C is about 138 μm.

(iii) Production of optical film C1 (polarizing plate) with adhesive layer through laminated separation film

With respect to the surface of the obtained optical film C on which the cyclic olefin resin film is bonded, the surface of the adhesive sheet 1 produced in (b) above and the separation film 1 on the opposite side (adhesive layer) After bonding, it was aged for 7 days under the conditions of a temperature of 23° C. and a relative humidity of 65% to obtain an optical film C1 (polarizing plate) having an adhesive layer of a laminated separation film having a layer composition shown in Table 2.

(VI) Reference example 2: Optical film C2 with adhesive layer through laminated separation film

Except that the adhesive sheet 2 produced in (b2) above was used instead of the adhesive sheet 1, the rest was the same as the production of the optical film C1 of the adhesive layer of the laminated separation film, and the layer structure shown in Table 2 was obtained. The optical film C2 with the adhesive layer of the laminated separation film.

The surface hardness of the optical films A1, A2, B1, B2, C1, and C2 with the adhesive layer of the laminated separation film produced above is determined by cutting each film into a size of 40mm×40mm, and then separating it from the adhesive layer. The film side is the opposite side. It is bonded to 40mm×40mm glass via an adhesive layer with a film thickness of 20μm, and the evaluation sample is bonded to the glass. The ultra-micro hardness tester is used in an environment of 23°C and 55% ( FISCHERSCOPE HM2000: Fisher Instruments Co., Ltd.), the Vickers hardness measured after applying a load at a pressurizing speed of 0.1N/5s and maintaining a load of 0.1N for 5 seconds".

3. Evaluation of the effect of preventing damage/dents of the optical film with the adhesive layer of the laminated separation film

According to the following method, the damage/dent prevention effect of the optical film via the adhesive layer of the laminated separation film was evaluated.

The optical films A1 (Example 1), B1 (Example 2), A2 (Comparative Example 1), B2 (Comparative Example 2), C1 (Reference Example 1) and C2 ( Reference example 2), cut into a size of 120mm×75mm so that the direction of the extension axis of the polarizer becomes the long side, and set on a firm and flat surface with the surface of the separation membrane facing upward. Use a scratch-type hardness tester (hardness test pencil model 318/318S manufactured by Erichsen) on the separation film surface of the "adhesive layer-attached optical film through the laminated separation film" to test the indentation resistance test. This test is a test in which a hemispherical tungsten tip is pressed with a predetermined fixing force on any part of the surface of the separation membrane (a radius of about 0.75 mm) to confirm whether there is a dent.

After pressing the scratch-type hardness tester on the surface of the separation membrane with a pressure of 0.1N for 5 seconds, the scratch-type hardness tester is moved away from the surface of the separation membrane. This operation was performed at 5 locations of the optical film with the adhesive layer of the laminated separation film, and 5 dents were made on the surface of the separation film. Immediately after leaving the tester on the surface of the separation membrane (initial) and 24 hours after leaving the separation membrane, visually confirm the state of dents remaining on the surface of the separation membrane. When there are residual dents, it is judged as "not eliminated", and when there is no remaining, it is judged as "wipe out". The "undestroyed number" at each time is shown in Table 3.

The optical film with the adhesive layer of Examples 1 and 2 in which the film thickness of the separation film is 45 μm or more and the film thickness of the polarizing plate (optical film) is 100 μm or less is to separate the scratch-type hardness tester from the surface of the separation film After 24 hours, even one dent (dent) did not remain. In contrast, the adhesive layer-attached optical films of Comparative Examples 1 and 2 in which the thickness of the separation film is less than 45 μm, after leaving the scratch-type hardness tester from the surface of the separation film for 24 hours, there are still residual dents. . Especially in Comparative Example 2, all the dents remained after 24 hours. Furthermore, optical films with a thickness of more than 100μm (Reference Examples 1 and 2) are not prone to dents due to the thickness of the optical film itself (138μm). Irrespective of the thickness of the separation film, dents after 24 hours Are all wiped out.

<Measurement of storage elastic modulus>

A plurality of adhesive layers are laminated so that the thickness becomes 0.6 mm. A cylinder with a diameter of 8 mm (height 0.6 mm) was punched out from the obtained adhesive layer, and this was used as a sample for measuring the storage elastic modulus G'.

With respect to the above sample, a viscoelasticity measuring device (manufactured by Physica Corporation, MCR300) was used in accordance with JIS K7244-6, and the storage elastic modulus (MPa) was measured by the torsion shear method under the following conditions.

[Measurement conditions]

Measurement frequency: 1Hz

Measuring temperature: 25℃

The storage elastic modulus of the adhesive layer formed of the above-mentioned adhesive composition (A) was 0.085 MPa.

(VII) Example 3: Optical film A3 with adhesive layer through laminated separation film (1) Preparation of (meth)acrylic resin B for adhesive layer

Put 94 parts by mass of n-butyl acrylate, 5.0 parts by mass of 2-hydroxyethyl acrylate, 1.0 part by mass of acrylic acid, and ethyl acetate into a reaction vessel equipped with a stirrer, a thermometer, a reflux cooler, a dripping device, and a nitrogen introduction tube. 200 parts by mass and 0.08 parts by mass of 2,2'-azobisisobutyronitrile, and the air in the reaction vessel was replaced with nitrogen. The reaction solution was heated to 60° C. while stirring in this nitrogen atmosphere, and after the reaction was allowed to react for 16 hours, it was cooled to room temperature. Here, the molecular weight of a part of the obtained solution was measured by the method described above, and it was confirmed that a (meth)acrylate polymer with a weight average molecular weight of 2 million had been produced.

(2) Preparation of adhesive composition (B)

100 parts by mass of the (meth)acrylate polymer obtained in the above step (1) (converted value of solid content; the same below) is used as an isocyanate-based crosslinking agent (B) modified with trimethylolpropane Tolyl diisocyanate [manufactured by Soken Chemical Co., Ltd., trade name "L-45"] 1.0 parts by mass, γ-glycidoxypropyltrimethoxysilane as a silane coupling agent (C) [manufactured by Shin-Etsu Chemical Co., Ltd. "KBM403"] 0.20 parts by mass, as the third (acryloxyethyl) trimeric isocyanate [manufactured by Toagosei Co., Ltd., trade name "M-315"] as a polyfunctional active energy ray hardening compound, 10 parts by mass 1 part by mass of 1-hydroxycyclohexyl phenyl ketone [manufactured by CIBA Specialty Chemical Co., Ltd., trade name "Irgacure 184"], which is a photopolymerization initiator, is mixed and thoroughly stirred, and diluted with ethyl acetate to obtain an adhesive The coating solution of the agent composition (B).

(3) Making the adhesive layer (adhesive sheet 3)

On the release treatment surface (peeling surface layer) of the separation membrane 1 obtained above, the adhesive composition (B) prepared in (a2) above was coated by an applicator so that the thickness after drying became 20 μm, and then After drying at 100°C for 1 minute, an adhesive layer 3 was obtained as an adhesive sheet 3. From the release sheet side, ultraviolet rays (UV) were irradiated under the following conditions to produce an adhesive sheet 3.

<UV irradiation conditions>

‧Electrodeless lamp manufactured by Fusion, using H bulb

‧Illuminance 600mW/cm ² , light intensity 150mJ/cm ² UV illuminance‧Light meter uses "UVPF-36" made by Eye Graphics.

<Measurement of storage elastic modulus>

Using the same method as the above-mentioned measuring method of the adhesive composition (A), the storage elastic modulus at 25°C of the adhesive layer formed of the adhesive composition (B) was measured. The storage elastic modulus at 25°C of the adhesive layer formed of the adhesive composition (B) is 0.55 MPa.

(4) Production of optical film A3 (polarizing plate) with adhesive layer through the laminated separation film

With regard to the surface of the obtained optical film B on which the cyclic olefin resin film is bonded, the surface of the adhesive sheet 3 produced in (3) above and the separation film 1 on the opposite side (adhesive layer) After bonding, it was aged for 7 days under the conditions of a temperature of 23° C. and a relative humidity of 65% to obtain an optical film A3 (polarizing plate) having an adhesive layer of a laminated separation film having a layer composition shown in Table 4.

Using the same method as in Example 1, the effect of preventing damage and dents on the optical film with the adhesive layer of the laminated separation film was evaluated. The results are shown in Table 4.

Since the diagram in this case contains content that has nothing to do with the abstract and is not a representative diagram of the case, there is no designated representative diagram in this case.

Claims (1)

An optical film with an adhesive layer attached to a laminated separation film, comprising: a separation film (C) laminated on at least one side of an optical film (A) via an adhesive layer (B); wherein, the aforementioned separation film (C) The film thickness of is 45 μm or more, and the film thickness of the aforementioned optical film (A) is 100 μm or less.

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