TWI534003B - Protective film for optical applications and process for producing the same, polarizing plate and process for producing the same - Google Patents

Description

Optical protective film, manufacturing method thereof, polarizing plate and manufacturing method thereof

The present invention relates to a protective film for optics, a method for producing the same, a polarizing plate, and a method for producing the same. More specifically, the present invention relates to a method for producing an optical protective film which is more effective in producing the optical protective film. An optical protective film having a hard coat function suitable for a polarizing plate and a quarter-wavelength film in a liquid crystal display device, or as a cover film for a touch panel, a cover film for a light disk, and a protective film for various displays, and the like The polarizing plate for the optical protective film described above and a method for producing the same.

Background technique

Optical protective films having a hard coat function have been conventionally used in various image display devices such as an LCD (Liquid Crystal Display), a touch panel, a CRT (Cathode Ray Tube), a PDP (Plasma Display Panel), and EL (Electroluminescence). In the case of components and the like, surface protection is used, and it is used for the purpose of preventing glare and anti-reflection. Moreover, it is also used in LCDs to protect polarizers. The optical protective film generally has a hard coat layer formed of heat hardening, active energy ray hardening or the like on the base film.

On the other hand, in recent years, the development of optical discs as information recording media has been remarkable. At the same time as the recording capacity has increased, CDs, DVDs, and even BDs have also been developed. As for BD, it has developed a recording capacity of up to about 50 GB. An optical protective film having a hard coat function as a protective film and a cover film is also often used in these optical disks.

However, the liquid crystal display device is a device that modulates the incident linearly polarized light by the electro-optical characteristics of the liquid crystal layer, and visualizes the polarizing plate on the emitting side as a transmittance and a colored signal. That is, the polarized light is used for the principle of its display, so the polarizing plate is an essential member. The polarizing plate is an element that converts natural light into linear polarization. In many cases, in particular, a polarizing plate used for mass production of a liquid crystal display device is dyed and adsorbed on a base film formed of a polyvinyl alcohol film by a dichroic material such as iodine or a dichroic dye. The polarizing film is formed by extending the orientation, and a protective film which is optically transparent and has mechanical strength is bonded to both surfaces or one surface of the polarizing film. Further, as the protective film, it is required to have small birefringence, high optical isotropy, high light transmittance, excellent heat resistance, excellent mechanical properties, good planarity, and good adhesion to a polarizer. For this reason, a cellulose-based film has been used (see Patent Document 1).

Now, as the cellulose-based film, triacetate (hereinafter also referred to as TAC) is generally used. However, the heat and moisture resistance of the TAC film is insufficient. When the polarizing plate used as the polarizer protective film of the TAC film is used under high humidity, the performance of the polarizing plate having a degree of polarization, a color tone, or the like is lowered.

Further, the TAC film has a phase difference with respect to the incident light in the oblique direction. This phase difference has recently accompanied the development of a large-sized liquid crystal display, and has significantly affected the viewing angle characteristics.

Further, in the liquid crystal display device, the light emitted from the normal light source is circularly polarized according to the circularly polarizing member, linearly polarized by the quarter-wavelength plate, and supplied to the polarizing plate. Further, for the above-mentioned quarter-wavelength sheet, an optical protective film having a hard coat function is also provided.

A polarizing plate in which a film obtained by molding an acrylic resin monomer or an acrylic resin composition is bonded to both surfaces is disclosed as a protective film having excellent moisture resistance and excellent durability (see Patent Document 2). However, it is necessary to use a binder at the time of bonding, and it is necessary to apply it before lamination, and it is not good in productivity, and it is optically used as a binder used when bonding a protective film on both surfaces. Although it is preferable to say that it is excellent in the homosexuality, only a general polyvinyl alcohol type binder, a urethane type binder, an epoxy type binder, and an acrylic type binder are just mentioned. In other words, when there is no regulation or any consideration regarding the type and properties of the binder of the binder layer according to the present invention, the visibility due to the difference in refractive index between the binder and the protective film may be deteriorated. Further, no hard coat layer was formed in the protective film.

Further, Patent Document 3 discloses an optical film and a polarizing plate obtained by forming the optical film on at least one surface of a polarizing plate, and the optical film is obtained by crosslinking and curing an ionizing radiation curable resin composition. The ionizing radiation curable resin composition contains (A) 70 to 95% by mass of a monofunctional (meth)acrylic polymer having a weight average molecular weight of 50,000 to 80,000 and (B) a polyfunctional radically polymerizable unsaturated double bond. The compound is 5 to 30% by mass. The optical film is a film having improved flexibility and film transportability, and as a binder for bonding to the optical film, a general PVA-based adhesive, an epoxy-based adhesive, an acrylic adhesive, and the like are exemplified. The polyolefin-based binder, the polyvinyl ether-based binder, and the rubber-based binder do not have any regulation regarding the type and properties of the binder. Their problem points are the same as above. Further, by adding the component (B) to the component (A), there is a concern that the optical characteristics are deteriorated due to phase separation or the like. Further, no hard coat layer was formed in the optical film.

As the protective film used in the polarizing plate, even if it is not the TAC film currently used, as long as it is excellent in transparency and optically isotropic, most extruded films can be replaced. However, since the polarizing film (polarizing sheet) is generally a polyvinyl alcohol-based film, it is difficult to adhere to the film, and in order to obtain a material which is inexpensive, it is not practical.

Patent literature

Patent Document 1: Japanese Patent Laid-Open No. Hei 7-120617

Patent Document 2: Japanese Laid-Open Patent Publication No. 2007-128025

Patent Document 3: Japanese Laid-Open Patent Publication No. 2008-129212

The present invention has been made under such circumstances, and an object thereof is to provide an optical protective film, a method for producing the same, and a polarizing plate using the optical protective film, and a method for producing the same, which is particularly suitable for use The polarizing plate is excellent in transparency and optical isotropy, and has good moisture resistance, excellent durability, good adhesion to a polarizing film, and a hard coat function.

In order to achieve the above object, the present inventors have conducted intensive studies for a long period of time, and as a result, have found that the following optical protective film can be obtained, which is composed of a hard coat layer/resin layer/adhesive layer, and which layer contains (methyl) When the acrylate-based compound is composed of 80% by mass or more, the reflection at the interface of each layer can be suppressed to an extremely low level, and the adhesion between the layers can be improved, and the film strength as a whole is also excellent.

Furthermore, it is found that the optical protective film is bonded to the polarizing film, and the adhesive layer and the resin layer containing 80% by mass or more of the (meth)acrylate compound are sequentially laminated on the other side of the polarizing film. The obtained polarizing plate has optical characteristics such as excellent visibility, and the strength of each layer can be efficiently improved. Therefore, a thin polarizing plate can be obtained as compared with the prior art. In addition, it has been found that a polarizing plate can be obtained, and a (meth)acrylate compound having excellent moisture resistance can be used as a main component of all layers except for the polarizing film of the polarizing plate of the present invention, whereby the obtained polarizing plate can be obtained. Both the moisture resistance and the light leakage resistance are superior to those of the conventional TAC film as the substrate. The present invention has been completed based on the above knowledge and knowledge.

That is, the present invention provides:

(1) A protective film for optics, which is a laminated film formed by sequentially laminating a hard coat layer (A), a resin layer (B), and an adhesive layer (C), wherein each layer contains 80 layers. A (meth) acrylate compound having a mass % or more.

(2) The optical protective film according to the above (1), wherein the resin layer (B) has a storage elastic modulus E' at a temperature of 23 ° C of 0.5 MPa or more.

The optical protective film according to the above aspect (1), wherein the adhesive layer (C) contains a polyfunctional active energy ray-curable compound and is irradiated with an active energy ray. The storage elastic modulus G' at a temperature of 23 ° C is 0.3 MPa or more.

The optical protective film according to any one of the above aspects, wherein the hard coat layer (A) irradiates the active energy ray-sensitive composition layer with an active energy ray. Forming.

The method for producing an optical protective film according to any one of the above aspects of the present invention, characterized in that

(a) a step of forming a resin layer (B) by casting on one side of the engineering sheet;

(b) a step of forming a hard coat layer (A) on the above resin layer (B);

(c) The step of peeling off the above-mentioned engineering sheet and bonding the surface of the adhesive layer (C) provided on the release sheet to the exposed resin layer (B).

(6) The method for producing an optical protective film according to the above aspect (5), wherein the hard coat layer in the step (b) is formed by irradiating an active energy ray-sensitive composition layer with an active energy ray. of.

(7) A polarizing plate obtained by laminating a polarizing film on the surface of the adhesive layer (C) of the optical protective film according to any one of the above items (1) to (4).

(8) A polarizing plate characterized in that the polarizing film is laminated on the surface of the adhesive layer (C) of the optical protective film according to any one of the above items (1) to (4), and Further, the adhesive layer (D) and the resin layer (E) are sequentially laminated on the other surface side of the polarizing film, and each of the layers (D) and (E) contains 80% by mass or more of (meth) acrylate. It is composed of layers of compounds.

(9) A polarizing plate with an adhesive layer, further comprising an adhesive layer (F) on the exposed surface side of the resin layer (E) of the polarizing plate according to (8) above, the adhesive The layer (F) contains 80% by mass or more of a (meth) acrylate-based compound.

(10) A method of producing a polarizing plate according to the above item (8), characterized by comprising:

(a) a step of forming a resin layer (B) by casting on one side of the engineering sheet;

(b) a step of forming a hard coat layer (A) on the above resin layer (B);

(c) a step of peeling the above-mentioned engineering sheet and bonding the surface of the adhesive layer (C) provided on the release sheet to the exposed resin layer (B) to be bonded;

(d) a step of peeling off the release sheet and bonding the exposed adhesive layer (C) surface to one surface of the polarizing film;

(e) a step of forming a resin layer (E) by casting on one side of another engineering sheet;

(f) a step of bonding the resin layer (E) so as to be bonded to the exposed side surface of the adhesive layer (D) provided on the release sheet;

(g) The step of peeling off the release sheet of the pressure-sensitive adhesive layer (D) and bonding it to the other surface of the polarizing film.

(11) The method for producing a polarizing plate according to the above aspect (10), wherein the hard coat layer (A) in the step (b) irradiates the active energy ray-sensitive composition layer with an active energy ray. Forming.

(12) The method for producing a polarizing plate according to the above (10) or (11), wherein the adhesive layer (C) and/or the adhesive layer (D) contain a polyfunctional active energy ray-curing type. a compound, and having (h) a step of irradiating the active energy ray after the above step (g).

(13) A method for producing a polarizing plate with an adhesive layer, characterized in that (k) the polarizing plate obtained in the above item (10) or (11) is exposed on the exposed surface of the resin layer (E) The step of bonding is performed by bonding the surface of the adhesive layer (F) provided on the release sheet.

(14) The method for producing a polarizing plate with an adhesive layer according to the above (13), characterized in that at least one of the adhesive layer (C), the adhesive layer (D) and the adhesive layer (F) One layer contains a polyfunctional active energy ray-hardening compound, and has (1) a step of irradiating the active energy ray after the above step (k).

According to the present invention, there is provided a protective film for optics, a method for efficiently producing the same, and a polarizing plate using the optical protective film, and a method for producing the same, which is particularly suitable for use as a polarizing plate, and has excellent transparency and optical properties. Simultaneously, it has good moisture resistance, excellent durability, good adhesion to a polarizing film, and a hard coat function.

Best form for implementing the invention

First, the optical protective film of the present invention will be described.

[Optical protective film]

The protective film for optical use of the present invention is characterized in that a laminated film formed by sequentially laminating a hard coat layer (A), a resin layer (B), and an adhesive layer (C) is contained in each layer in an amount of 80% by mass or more. The (meth) acrylate type compound has a total thickness of the (A) layer, the (B) layer, and the (C) layer of 15 to 130 μm. Moreover, the (meth)acrylate type compound means an acrylate type compound and / or a methacrylate type compound. Similar words also mean the same meaning. Further, it is contained in a monomer unit which is a polymer or a cured product.

[Resin layer (B)]

In the optical protective film of the present invention, the resin layer formed as the (B) layer is a (meth) acrylate-based compound, and is a layer containing 80% by mass or more of a (meth) acrylate (co)polymer.

The resin layer contains a weight average molecular weight (Mw) of 50,000 to 500,000 and a molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) of 1.5 to 3.0 from the viewpoint of mechanical properties and moldability. The (meth) acrylate (co)polymer is preferred. When the weight average molecular weight Mw is less than 50,000, the film strength of the obtained resin layer may be lowered. When the weight average molecular weight Mw is more than 500,000, the viscosity may become too high, and workability may be lowered. In addition, when the molecular weight distribution is narrower than 1.5, the obtained resin layer may have poor impact resistance. When the molecular weight distribution exceeds 3.0, the physical strength of the obtained resin layer may be lowered, and the dimensional accuracy may be deteriorated. From such a viewpoint, the weight average molecular weight Mw is more preferably in the range of 100,000 to 300,000, and particularly preferably in the range of 150,000 to 250,000. Further, the (co)polymer refers to a homopolymer and/or a copolymer.

The above weight average molecular weight (Mw) and number average molecular weight (Mn) are values converted to standard polystyrene measured by a gel permeation chromatography (GPC) method.

In addition, the resin layer contains methyl methacrylate homopolymer and/or from the viewpoint of balance of transparency, moisture resistance, optical isotropy, mechanical strength, water absorption, dimensional stability and the like. Or a (meth) acrylate copolymer having a methyl methacrylate unit of 80% by mass or more is preferred.

When the resin layer is the above-mentioned (meth) acrylate copolymer, as the (meth) acrylate copolymerized with methyl methacrylate, for example, an alkyl group having a carbon number of about 2 to 20 may be used. A monofunctional (meth) acrylate monomer. Specifically, it can be derived from ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, hexyl (meth)acrylate, (A) Cyclohexyl acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate, isobornyl (meth) acrylate And at least one of 2-hydroxyethyl acrylate and the like is appropriately selected and used.

The (meth) acrylate for copolymerization is preferably used in an amount of 20% by mass or less based on all of the monomers, and is suitably used for imparting flexibility to the resin layer. Further, at least one of a monomer (carboxyl group-containing monomer) such as (meth)acrylic acid, crotonic acid, maleic acid or itaconic acid may be used in place of or in combination with the (meth) acrylate for copolymerization. use. In this case as well, the total amount of the monomers for copolymerization is preferably 20% by mass or less based on the total amount of the monomers.

The polymerization method is not particularly limited, and various methods such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, and the like can be employed.

The resin layer is preferably formed by a casting method (solution casting method). Specifically, first, the (meth) acrylate (co)polymer produced as described above is dissolved in a suitable organic solvent such as ethyl acetate, methyl ethyl ketone, or toluene, etc., and further, a plasticizer is added. Additives such as sugar-like glue. After completely removing impurities and bubbles, the dope is used as a support, for example, by using an engineering sheet, and flowing on one surface thereof to form the resin layer. Further, as an engineering piece, if it is generally used, it can be used without limitation. For example, a polyolefin-based film or a polyethylene terephthalate film having a decane-based or fluorine-based release layer provided on the surface side in contact with the resin layer is preferably used.

The resin layer containing the (meth) acrylate (co)polymer thus formed has a thickness of about 10 to 80 μm, preferably 20 to 50 μm, and preferably has a storage elastic modulus E' at a temperature of 23 ° C. It is more preferably 0.5 MPa or more and 2 MPa or more. The upper limit is not particularly limited and is usually about 70 MPa. When the thickness of the resin layer is in the above range, the performance as a protective film can be sufficiently exhibited. When the storage elastic modulus E' is less than 0.5 MPa, the mechanical strength of the resin layer is low, and the performance as a protective film is insufficient.

Further, the storage elastic modulus E' at a temperature of 23 ° C is a value measured based on JIS K 7244-4.

[hard coating (A)]

In the optical protective film of the present invention, a hard coat layer is provided as the (A) layer on the resin layer (B) formed as described above. By providing the hard coat layer, not only scratching of the surface but also the film strength of the optical protective film can be improved, and the film thickness of the resin layer can be reduced.

In the formation of the hard coat layer, an active energy ray-sensitive composition can be employed.

<Active Energy Line Inductive Composition>

The active energy ray-sensitive composition preferably contains (i) a polyfunctional (meth) acrylate monomer and/or a (meth) acrylate prepolymer, and (ii) cerium oxide particles. / or (iii) organic particles.

Further, in the present invention, the active energy ray means a portion having an energy ray in an electromagnetic wave or a charged particle ray, that is, an ultraviolet ray, an electron beam, or the like. (1) (i) a polyfunctional (meth) acrylate monomer and/or a (meth) acrylate prepolymer

In the present invention, a polyfunctional (meth)acrylate monomer and/or a (meth)acrylate prepolymer is used as the active energy ray-inductive composition.

The polyfunctional (meth)acrylate monomer may, for example, be 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate or neopentane. Diol (meth) acrylate, polyethylene glycol di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, dicyclopentyl di (meth) acrylate, Caprolactone modified dicyclopentenyl di(meth)acrylate, ethylene oxide modified di(meth)acrylate, allylated cyclohexyl di(meth)acrylate, di(A) Isopropyl methacrylate, trimethylolpropane tri(meth) acrylate, dipentaerythritol tri(meth) acrylate, propionic acid modified dipentaerythritol tri(meth) acrylate, pentaerythritol tri ( Methyl) acrylate, propylene oxide modified trimethylolpropane tri(meth) acrylate, tris(propyloxyethyl)isocyanate, propionic acid modified dipentaerythritol penta (methyl) A polyfunctional (meth) acrylate such as acrylate, dipentaerythritol hexa(meth) acrylate or caprolactone-modified dipentaerythritol hexa(meth) acrylate. These monomers may be used alone or in combination of two or more.

On the other hand, the (meth)acrylate prepolymer may, for example, be a polyester acrylate type, an epoxy acrylate type, a urethane acrylate type, or a polyol acrylate type. Here, as the polyester acrylate-based prepolymer, the hydroxyl group of the polyester oligomer having a hydroxyl group at both terminals, which can be obtained by, for example, condensation of a polyvalent carboxylic acid and a polyhydric alcohol, may be (meth)acrylated, or in a plurality of A hydroxyl group at the terminal of the oligomer obtained by adding an alkylene oxide to a carboxylic acid is obtained by (meth)acrylation.

The epoxy acrylate-based prepolymer can be obtained, for example, by reacting and esterifying a relatively low molecular weight bisphenol epoxy resin or an oxirane ring of a novolac epoxy resin with (meth)acrylic acid. A urethane acrylate-based prepolymer which can be esterified with (meth)acrylic acid by, for example, a polyurethane polyol, a polyester urethane oligomer obtained by reacting a polyester polyol with a polyisocyanate And get it. Further, the polyol acrylate-based prepolymer can be obtained by esterification of a hydroxyl group of a polyether polyol with (meth)acrylic acid. These prepolymers may be used alone or in combination of two or more. Further, the above polyfunctional (meth)acrylate monomers may be used in combination.

(2) (ii) cerium oxide particles

In the present invention, as the (ii) cerium oxide-based fine particles, colloidal cerium oxide fine particles and/or cerium oxide fine particles having surface functional groups may be used.

The colloidal cerium oxide microparticles have an average particle diameter of about 1 to 400 nm, or as the cerium oxide microparticle having a surface functional group, for example, a group containing a (meth) acryl fluorenyl group as a surface functional group. Antimony particles (hereinafter also referred to as reactive ceria particles).

The reactive cerium oxide fine particles may, for example, be a polymerizable unsaturated group having a stanol group on the surface of the cerium oxide fine particles having an average particle diameter of about 0.005 to 1 μm and a functional group capable of reacting with the stanol group. The organic compound is reacted and thus obtained. The polymerizable unsaturated group may, for example, be a radically polymerizable (meth) acrylonitrile group.

The polymerizable unsaturated group-containing organic compound having a functional group reactive with the above stanol group is, for example, preferably a compound represented by the following formula (I).

(wherein R ¹ is a hydrogen atom or a methyl group, and R ² is a halogen atom or

The group represented. )

As such a compound, for example, acrylic acid, acrylonitrile chloride, 2-isocyanoethyl acrylate, glycidyl acrylate, 2,3-iminopropyl acrylate, 2-hydroxyethyl acrylate, acryloxy group can be used. Propyltrimethoxydecane or the like and a methacrylic acid derivative corresponding to these acrylic acid derivatives. These acrylic acid derivatives and methacrylic acid derivatives may be used singly or in combination of two or more.

The cerium oxide fine particles in which the organic compound having the polymerizable unsaturated group obtained as described above is bound as an active energy ray hardening component are crosslinked and hardened by irradiation with an active energy ray.

The reactive cerium oxide fine particles have an effect of improving the scratch resistance of the obtained hard coat film.

A compound obtained by combining such an organic compound having a polymerizable unsaturated group with such a cerium oxide microparticle as an active energy ray-sensitive composition containing the compound, and a product name such as JSR (trade) is commercially available. [OPSTAR Z7530], [OPSTAR Z7524], [OPSTAR TU4086], etc.

In the present invention, the content of the ceria-based fine particles of the component (ii) is usually from about 5 to 90% by mass, preferably from 10 to 70% by mass, based on the solid content of the active energy ray-inductive composition.

Further, the average particle diameter of the cerium oxide fine particles in the cerium oxide-based fine particles of the component (ii) can be measured by a laser diffraction scattering method. In this method, the average particle diameter is measured by irradiating the liquid in which the fine particles are dispersed with the intensity of the diffraction or scattered light when the laser is irradiated.

(3) (iii) organic particles

In the present invention, (ii) cerium oxide-based fine particles may be changed to (or used in combination with) (iii) organic fine particles.

Examples of the organic fine particles include siloxane oxide fine particles, melamine resin fine particles, acrylic resin fine particles, acrylic-styrene copolymer fine particles, polycarbonate fine particles, polyethylene fine particles, and polystyrene fine particles. Benzoguanamine-based resin fine particles and the like.

In the present invention, all of the hard coat layer (A), the resin layer (B), and the pressure-sensitive adhesive layer (C) have a (meth) acrylate-based compound as a main component, thereby reflecting at the interface, The refractive inhibition is suppressed to a minimum level, and an optical protective film having good visibility can be obtained. From this point of view, the organic fine particles are also particularly excellent in the use of acrylic resin fine particles.

In addition, the shape of the organic fine particles is not particularly limited, but a spherical shape is preferable from the viewpoint of uniformity of antiglare performance, improvement of reproducibility, and the like.

Further, the average particle diameter is preferably 6 to 10 μm from the viewpoint of antiglare performance, and the particle size distribution is preferably 70% or more by weight in the range of the average particle diameter of ± 2 μm. Further, the average particle diameter and particle size distribution of the organic fine particles refer to values measured by the Coulter's counting method.

In the present invention, the organic fine particles of the component (iii) may be used alone or in combination of two or more. In addition, the amount of the solid energy component of the active energy ray-sensitive composition of the component (i) is preferably 0.1 to 30 parts by mass, more preferably 1 to 20, from the viewpoint of anti-glare performance. Parts by mass.

(4) Photopolymerization initiator

The active energy ray-inductive composition in the present invention may contain a photopolymerization initiator as desired. Examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, and dimethylamino group. Acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-benzene Propione-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-propan-1-one, 4- (2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)one, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone , dichlorobenzophenone, 2-methyl hydrazine, 2-ethyl hydrazine, 2-tert-butyl fluorene, 2-amino hydrazine, 2-methyl thioxanthone, 2-B Thiophenone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, acetophenone dimethyl condensate Ketone, p-dimethylamino benzoate and the like.

These may be used alone or in combination of two or more. The amount of addition of the active energy ray-sensitive compound to 100 parts by mass is usually selected from the range of 0.2 to 10 parts by mass. Here, in the case where all of the active energy ray-sensitive compounds are used, it is necessary to include (ii) cerium oxide-based fine particles when using reactive cerium oxide fine particles.

(5) Active energy line sensing composition

The active energy ray-inductive composition used in the present invention comprises the above-mentioned (i) component, (ii) and/or (iii) component, and a photopolymerization initiator which is preferably used, and various additives in a suitable solvent. For example, an antioxidant, an ultraviolet absorber, a decane coupling agent, a light stabilizer, a leveling agent, an antifoaming agent, and the like are added, dissolved, or dispersed in a predetermined ratio, thereby being formulated.

As the solvent to be used at this time, for example, an aliphatic hydrocarbon such as hexane or heptane, an aromatic hydrocarbon such as toluene or xylene, a halogenated hydrocarbon such as dichloromethane or vinyl chloride, or methanol, ethanol, propanol, butanol or propylene glycol can be used. An alcohol such as monomethyl ether, a ketone such as acetone, methyl ethyl ketone, 2-pentanone, isophorone or cyclohexanone; an ester such as ethyl acetate or butyl acetate; or a cellosolve such as ethyl cellosolve.

The concentration and viscosity of the hard coat layer forming material to be blended as described above are not particularly limited as long as they can be applied, and can be appropriately selected depending on the situation.

<Formation of Hard Coating (A)>

In the present invention, the active energy ray-inductive composition is applied to the resin layer (B) formed as described above by a conventionally known method such as a bar coating method, a blade coating method, a roll coating method, or a knife coating method. A die coating method, a gravure printing method, or the like is applied to form a coating film, and after drying, an active energy ray is applied thereto, and the coating film is cured to form a hard coat layer (A).

Examples of the active energy ray include ultraviolet rays, electron beams, and the like. The ultraviolet ray may be obtained by a high pressure mercury lamp, an electrodeless lamp, a halogen lamp, a xenon lamp or the like, and the irradiation amount is usually 100 to 500 mJ/cm ² , and the electron beam is obtained by an electron beam accelerator or the like, and the irradiation amount is usually 150 to 350 kV. Among the active energy rays, ultraviolet rays are particularly suitable. Further, when an electron beam is used, a cured film can be obtained without adding a photopolymerization initiator.

The thickness of the hard coat layer thus formed is usually about 2 to 20 μm, preferably 4 to 10 μm.

(adhesive layer (C))

In the optical protective film of the present invention, an adhesive layer is provided as the (C) layer on the opposite side of the hard coat layer side of the resin layer (B).

The formation of the adhesive layer (C) is preferably carried out using an active energy ray-curable adhesive material containing a polyfunctional active energy ray-curable compound.

<Active Energy Line Hardening Adhesive Material>

The active energy ray-curable adhesive material (hereinafter simply referred to as an adhesive material) preferably contains (iv) a (meth) acrylate copolymer, (v) a polyfunctional active energy ray-curable compound, and (vi) The crosslinking agent and, if necessary, (vii) a photopolymerization initiator.

(1) (iv) (meth) acrylate copolymer

In the adhesive material of the present invention, the (meth) acrylate copolymer contained as the component (iv) is not particularly limited, and a (meth) acrylate copolymer which has been conventionally used as a resin component of a binder can be used. It is appropriate to choose any ingredient. As such a (meth) acrylate copolymer, for example, a (meth) acrylate having an alkyl group having an ester moiety of 4 to 20 and a functional monomer having an active hydrogen may be mentioned. A copolymer formed from other monomers employed as desired.

Here, examples of the (meth) acrylate having 4 to 20 carbon atoms of the alkyl group as the ester moiety include butyl (meth)acrylate, amyl (meth)acrylate, and (methyl). Hexyl acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, decyl (meth)acrylate, dodecane (meth)acrylate A base ester, a tetradecyl (meth)acrylate, a hexadecyl (meth)acrylate, an octadecyl (meth)acrylate, or the like. These may be used alone or in combination of two or more.

On the other hand, examples of the monomer having a functional group having active hydrogen include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 3-hydroxy(meth)acrylate. Propyl ester, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc. (meth)acrylic acid alkyl (meth)acrylate; (meth)acrylic acid Monomethylaminoethyl ester, monoethylaminoethyl (meth)acrylate, monomethylaminopropyl (meth)acrylate, monoethylaminopropyl (meth)acrylate, etc. a monoalkylaminoalkyl acrylate; an ethylenically unsaturated carboxylic acid such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid or citric acid. These monomers may be used singly or in combination of two or more.

Further, examples of the other monomer to be used as desired include carbon atoms of an alkyl group of an ester moiety such as methyl (meth)acrylate, ethyl (meth)acrylate or propyl (meth)acrylate. a (meth) acrylate of 1 to 3; a vinyl ester such as vinyl acetate or vinyl propionate; an olefin such as ethylene, propylene or isobutylene; a halogenated olefin such as vinyl chloride or vinylidene chloride; a styrene monomer such as ethylene or α-methylstyrene; a diene monomer such as butadiene, isoprene or chloroprene; and a nitrile monomer such as acrylonitrile or methacrylonitrile. An acrylamide such as acrylamide, N-methyl acrylamide or N,N-dimethyl acrylamide. These may be used alone or in combination of two or more. From the viewpoint of imparting an adhesive force to the obtained binder layer, the (iv) (meth) acrylate copolymer is preferably 50% by mass or more, more preferably 60% of the monomers constituting the copolymer. ~99% by mass or more is composed of a (meth) acrylate having an alkyl group of the above ester moiety and having 4 to 20 carbon atoms.

The copolymerization form of the (meth) acrylate copolymer is not particularly limited, and any of a random copolymer, a block copolymer, and a graft copolymer may be used. Further, the molecular weight is preferably 500,000 or more, and more preferably 500,000 to 2,500,000. If the weight average molecular weight is less than 500,000, there is a risk that the adhesion to the adherend and the durability of the adhesive are insufficient. The weight average molecular weight is preferably from 700,000 to 2,000,000 in consideration of the adhesion and the durability of the adhesive.

Further, the weight average molecular weight is a value converted into standard polystyrene measured by a gel permeation chromatography (GPC) method.

Further, in the (meth) acrylate copolymer, the content of the monomer unit having a functional group having an active hydrogen is preferably in the range of 0.01 to 10% by mass. When the content is less than 0.01% by mass, the crosslinking point is too small, the crosslinking is insufficient, and the adhesive layer may be agglomerated and destroyed. If it exceeds 10% by mass, the adhesion to the liquid crystal cell or the like may be lowered. A more preferable content of the monomer unit having a functional group having the active hydrogen is in the range of 0.05 to 6.0% by mass, particularly preferably in the range of 0.2 to 5.0% by mass. Further, in order to achieve the object of the present invention, as the monomer having a functional group having an optimum active hydrogen, 2-hydroxyethyl (meth)acrylate and acrylic acid are exemplified, and (meth) acrylate copolymerization is preferred. The monomer has a monomer unit of 0.3 to 10% by mass, particularly preferably 0.5 to 5.0% by mass.

In the present invention, the (meth) acrylate copolymer may be used singly or in combination of two or more kinds as the component (iv).

(2) (v) polyfunctional active energy ray-hardening compound

In the adhesive material of the present invention, the polyfunctional active energy ray-curable compound used as the component (v) has a weight average molecular weight of usually 100,000 or less, preferably 300 to 10,000.

As such an active energy ray-curable compound, for example, an active energy ray-curable polyfunctional prepolymer and/or an active energy ray-curable polyfunctional monomer can be exemplified. The active energy ray-curable polyfunctional prepolymer is a radical polymerization type and a cationic polymerization type, and as the radical polymerization type active energy ray-curable polyfunctional prepolymer, for example, a polyester acrylate type or an epoxy resin is exemplified. An acrylate type, a urethane acrylate type, a polyol acrylate type, etc.

Here, as the polyester acrylate-based prepolymer, a hydroxyl group of a polyester oligomer having a hydroxyl group at both terminals can be obtained by, for example, condensation of a polyvalent carboxylic acid and a polyhydric alcohol using (meth)acrylic acid. The esterification is carried out by esterifying a hydroxyl group at the terminal of the oligomer obtained by adding an alkylene oxide to a polyvalent carboxylic acid by using (meth)acrylic acid. The epoxy acrylate-based prepolymer can be obtained, for example, by reacting (meth)acrylic acid in an oxirane ring of a lower molecular weight bisphenol type epoxy resin or a novolac type epoxy resin. . A urethane acrylate-based prepolymer, for example, a polyurethane oligomer obtained by a reaction of a polyether polyol, a polyester polyol, and a polyisocyanate by using (meth)acrylic acid Obtained by esterification. Further, the polyol acrylate-based prepolymer can be obtained by esterifying a hydroxyl group of the polyether polyol by using (meth)acrylic acid. These active energy ray-curable polyfunctional prepolymers may be used alone or in combination of two or more.

On the other hand, as the cationic polymerization type active energy ray-curable polyfunctional prepolymer, an epoxy resin is usually used. Examples of the epoxy resin include a compound which epoxidizes a polyhydric phenol such as a bisphenol resin or a phenol resin by using epichlorohydrin or the like, and a linear olefin compound or a cyclic olefin using a peroxide or the like. A compound obtained by oxidizing a compound or the like.

Further, examples of the active energy ray-curable polyfunctional monomer include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and neopentane. Diol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(methyl) Acrylate, dicyclopentyl di(meth) acrylate, caprolactone modified dicyclopentenyl di(meth) acrylate, ethylene oxide modified di(meth) acrylate, allylic Cyclohexyl bis(meth) acrylate, di(meth)acrylic acid isocyanurate, trimethylolpropane tri(meth) acrylate, dipentaerythritol tri(meth) acrylate, propionic acid Modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, tris[(methyl)propylene decyloxyalkane Iso-isocyanurate, propionic acid-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa(meth) acrylate, caprolactone-modified dipentaerythritol hexa(meth) propylene Multifunctional acrylate ester. These active energy ray-curable polyfunctional monomers may be used singly or in combination of two or more kinds, and the active energy ray-curable polyfunctional prepolymer may be used in combination.

In the present invention, the polyfunctional active energy ray-curable compound as the component (v) can reduce the crosslinking point, and from the viewpoint of increasing the crosslinking density, a polyfunctional monomer is preferred as a suitable component. For example, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, tris[(meth) propylene decyloxyalkyl] isocyanurate, etc. are mentioned.

Among them, tris[(meth)acryloxyalkyl]isocyanurates are particularly preferably used. The tris[(meth)acryloxyalkyl]isocyanurate is preferably exemplified by tris(2-propenyloxyethyl)isocyanate or tris(3). - propylene methoxy propyl) iso-isocyanate, tris(2-methylpropenyloxyethyl)isocyanate, tris(3-methylpropenyloxypropyl) iso-tris Polycyanate, etc.

In the present invention, the content of the polyfunctional active energy ray-curable compound as the component (v) is preferably in the solid content of the adhesive material used in the present invention from the viewpoint of adhesion to the polarizing film. It is contained in a ratio of 5 to 50% by mass, and more preferably in a ratio of 10 to 30% by mass.

(3) (vi) crosslinker

The crosslinking agent to be used as the component (vi) in the adhesive material of the present invention is not particularly limited, and any material which is conventionally used as a crosslinking agent in the conventional acrylic resin can be appropriately selected and used. Examples of such a crosslinking agent include a polyisocyanate compound, an epoxy resin, a melamine resin, a urea resin, a dialdehyde, a methylol polymer, an aziridine compound, a metal chelate compound, and a metal alcohol. As the salt, the metal salt or the like, a polyisocyanate compound is preferably used.

Here, examples of the polyisocyanate compound include aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and xylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; and isophorone II. An alicyclic polyisocyanate such as isocyanate or hydrogenated diphenylmethane diisocyanate, and a biuret or isomeric cyanate thereof, and also as ethylene glycol, propylene glycol, neopentyl glycol, and trishydroxyl An adduct of a reactant of a low molecular weight active hydrogen-containing compound such as methyl propane or castor oil (for example, trimethylolpropane-modified benzylidene isocyanate) or the like.

In the present invention, the crosslinking agent may be used alone or in combination of two or more. In addition, the amount of use thereof varies depending on the type of the crosslinking agent, and is usually 0.01 to 20 parts by mass, preferably 0.1 to 10, per 100 parts by mass of the (meth) acrylate copolymer as the component (iv). Selected within the range of parts by mass.

(4) (vii) photopolymerization initiator

In the active energy ray-curable adhesive material, a photopolymerization initiator may be contained as needed. As the photopolymerization initiator, the same ones as those described in the hard coat layer (A) can be used.

In the adhesive material, the content of the photopolymerization initiator to be used as described above is usually about 0.5 to 20 parts by mass based on 100 parts by mass of the polyfunctional prepolymer and/or monomer as the component (v). Preferably, it is 1 to 15 parts by mass. Further, when the electron beam is used as the active energy ray, it is not necessary to contain the above photopolymerization initiator.

<Preparation of coating liquid containing active energy ray-curable adhesive material>

The method of formulating the coating liquid containing the active energy ray-curable adhesive material is not particularly limited, and for example, a (meth) acrylate copolymer of the above (iv) component and a polyfunctional component (v) may be added to the solvent. The active energy ray-curable compound, the crosslinking agent of the component (vi), and the photopolymerization initiator of the component (vii) used as needed, and various additives such as an antioxidant, an ultraviolet absorber, and a light stabilizer A decane coupling agent, an antistatic agent, a leveling agent, an antifoaming agent, and the like are mixed and mixed to prepare a coating liquid containing an active energy ray-curable adhesive material.

Examples of the solvent include aliphatic hydrocarbons such as hexane and heptane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as dichloromethane and dichloroethane, and methanol, ethanol, propanol, butanol, and the like. Alcohol, acetone, methyl ethyl ketone, 2-pentanone, isophorone, cyclohexanone and other ketones, ethyl acetate, butyl acetate and other esters, ethyl cellosolve and other cellosolve solvents, propylene glycol monomethyl ether and other alcohols Ether solvent, etc. These solvents may be used alone or in combination of two or more.

The concentration of the active energy ray-curable bonding material in the coating liquid is not particularly limited as long as it is a viscosity suitable for coating.

<Formation of Adhesive Layer (C)>

In the optical protective film of the present invention, an adhesive layer is provided as the (C) layer on the surface opposite to the hard coat layer side of the resin layer (B). The formation of the adhesive layer can be carried out as follows.

For example, when a resin layer (B) having a hard coat layer (A) on the surface of the work piece is provided, the work piece may be first peeled off to expose a surface opposite to the hard coat layer side of the resin layer, and the exposed surface may be directly exposed. Applying a coating liquid containing the above-mentioned adhesive material, heating and drying it to form an adhesive layer, or applying a coating liquid containing the adhesive material on a release-treated surface of a release sheet, heating and drying to form an adhesive A layer and a method of transferring it to the exposed surface of the above resin layer. Further, in the adhesive layer, in order to protect it, it is preferred to adhere the release sheet in advance.

In the present invention, as a method of applying a coating liquid containing an adhesive material, for example, a doctor blade coating method, a roll coating method, a bar coating method, a knife coating method, a die coating method, a gravure printing method, or the like can be used.

Further, examples of the release sheet include papers such as cellophane, coated paper, and laminated paper, and a release agent such as a decyl oxide resin coated on various plastic films. The thickness of the release sheet is not particularly limited and is usually about 20 to 150 μm.

The thickness of the adhesive layer thus formed is usually about 3 to 30 μm, preferably in the range of 5 to 20 μm. In addition, the storage elastic modulus G' at a temperature of 23 ° C after the irradiation of the active energy ray is preferably 0.3 MPa or more, and more preferably 0.5 MPa or more from the viewpoint of durability and the like. The upper limit is not particularly limited and is usually about 30 MPa.

Further, the above storage elastic modulus (G') is a value measured in accordance with JIS K 7244-6.

The optical protective film of the present invention is bonded to the adherend by the adhesive layer, and the active energy ray is applied thereto, whereby the optical protective film is adhered to the adherend with good sealing properties.

The pressure-sensitive adhesive layer and the polarizing film (especially a polyvinyl alcohol-based polarizing film) are excellent in sealing properties.

Examples of the active energy ray include ultraviolet rays, electron beams, and the like. The above ultraviolet rays can be obtained using a high pressure mercury lamp, an electrodeless lamp, a xenon lamp, or the like. On the other hand, the electron beam can be obtained by an electron beam accelerator or the like. Among the active energy rays, ultraviolet rays are particularly suitable. Further, when an electron beam is used, it is not necessary to add a photopolymerization initiator.

The amount of irradiation of the adhesive layer as the active energy ray varies depending on the thickness of the adhesive layer, and in the case of ultraviolet ray, it is preferably 50 to 1000 mW/cm ² and the amount of light is 50 to 1000 mJ/cm ² , in the case of an electron beam. It is preferably in the range of 10 to 1000 krad.

Next, a method of producing the optical protective film of the present invention will be described.

[Method of Manufacturing Optical Protective Film]

The method for producing an optical protective film of the present invention is characterized by comprising:

(a) a step of forming a resin layer (B) by casting on one side of the engineering sheet;

(b) a step of forming a hard coat layer (A) on the above resin layer (B);

(c) The step of peeling off the above-mentioned engineering sheet and bonding the surface of the adhesive layer (C) provided on the release sheet to the exposed resin layer (B).

The resin layer (B), the hard coat layer (A) and the adhesive layer (C) in the above steps (a), (b) and (c) are as shown in the above description.

When the optical protective film of the present invention is used as the surface protective film of various image display devices, an antireflection layer for generating antireflection such as argon oxide may be provided on the surface of the hard coat layer as needed. A film, a fluorine film, or the like. In this case, the thickness of the antireflection layer is suitably about 0.05 to 0.2 μm. Further, the reflectance at a wavelength of 550 nm is preferably 3.5% or less. By providing the anti-reflection layer, it is possible to eliminate the reflection of a screen caused by reflection of sunlight, a fluorescent lamp, or the like, and by suppressing the reflectance of the surface, the total light transmittance is improved, and the transparency is improved.

Further, in the above hard coat layer, a surface protective film may be provided as needed.

The optical protective film of the present invention thus obtained has a total thickness of the (A) layer, the (B) layer, and the (C) layer in the range of 15 to 130 μm, preferably in the range of 29 to 80 μm.

The optical protective film of the present invention has a hard coat function and is suitable for use as a polarizing plate or a quarter-wave plate in a liquid crystal display device, or a protective film for a touch panel, a disc, and a protective film for various magnetic sheets, etc. Suitable as a protective film for polarizing plates.

The invention also provides a polarizing plate. The polarizing plate of the present invention will be described below.

[Polarizer]

The polarizing plate of the present invention is laminated as follows, and the exposed surface side of the pressure-sensitive adhesive layer (C) of the optical protective film of the present invention is bonded to the polarizing film, and further laminated on the other surface side of the polarizing film. Adhesive layer (D), resin layer (E).

<polarized film>

The polarizing film used in the present invention is generally used, and is not particularly limited. Preferably, for example, a film in which a hydrophilic polymer film adsorbs iodine or a dichroic dye to extend orient it is mentioned. As a specific example, a polyvinyl alcohol-based film can be obtained by dyeing, adsorbing iodine or a dichroic dye, uniaxially stretching in an aqueous solution of boric acid, and maintaining the stretched state, washing and drying, thereby obtaining a polarizing film. The magnification of the uniaxial extension is usually about 4 to 8 times. As a polyvinyl alcohol-based film, "KURARAY VINYLON" (manufactured by Kuraray Co., Ltd.), "TOHCELLO VINYLON" (manufactured by TOHCELLO Co., Ltd.), and "NIHON VINYLON" (manufactured by Nippon Synthetic Chemical Co., Ltd.) can be used. Product.

<Adhesive layer (D)>

The adhesive layer (D) in the present invention can be formed by the same composition and method as the above-mentioned adhesive layer (C). The adhesive layer (D) is preferably the same as the adhesive layer (C) from the viewpoint of productivity and optical properties.

<Resin layer (E)>

The resin layer (E) in the present invention can be formed by the same composition and method as the above-mentioned resin layer (B). The resin layer (E) is preferably the same as the resin layer (B) from the viewpoint of productivity and optical characteristics.

<Method of Manufacturing Polarizing Plate>

As a method of producing a polarizing plate, (a) a resin layer (B) is formed on one surface of the engineering sheet by a casting method, (b) a hard coat layer (A) is formed on the resin layer (B), and (c) The above-mentioned engineering sheet is peeled off, and the surface of the adhesive layer (C) provided on the release sheet is bonded to the exposed resin layer (B) surface to bond it, thereby producing an optical sheet having a release sheet on the adhesive layer (C). Protective film. Further, the formation of the hard coat layer (A) in the above (b) is preferably carried out by irradiating an active energy ray on the active energy ray-inductive composition layer.

Next, (d) the release sheet is peeled off, and the exposed surface of the adhesive layer (C) is bonded to the other surface of the polarizing film.

On the other hand, (e) forming a resin layer (E) by casting on one surface of another engineering sheet, (f) following the surface of the adhesive layer (D) provided on the release sheet and the above resin layer (E) The film is bonded in abutting manner, thereby preparing a protective film for protecting the other surface side of the polarizing film.

Next, (g) the release sheet of the pressure-sensitive adhesive layer (D) is peeled off, and the other surface of the polarizing film is bonded to each other to prepare a polarizing plate of the present invention.

Here, the adhesive layer (C) and the polarizing film, and the adhesive layer (D) and the polarizing film have better sealing properties, and in order to further increase the strength of the polarizing plate, the adhesive layer (C) and the adhesive layer (D) are preferable. At least one of them, preferably both, contains a polyfunctional active energy ray-hardening compound. In this case, it is preferable to use as a polarizing plate which irradiates an active energy ray after bonding with a polarizing film.

The irradiation timing of the active energy ray may be performed after bonding the polarizing film and each of the adhesive layers. From the viewpoint of simplification of the step, it is preferred that (h) the active energy ray is irradiated together after the polarizing plate of the above (g) is produced. . Alternatively, the active energy rays may be irradiated from above the hard coat layer (A), or from above the resin layer (E), or from either side of both sides. The type of the active energy ray, the irradiation conditions, and the like are as described above.

[Polarizing Plate with Adhesive Layer]

In order to bond the liquid crystal cell or other optical member, the polarizing plate of the present invention is preferably a polarizing plate having an adhesive layer (F) on the exposed surface side of the resin layer (E).

<Adhesive layer (F)>

The adhesive layer (F) in the present invention can be formed by the same composition and method as the above-mentioned adhesive layer (C). The adhesive layer (F) is preferably the same as the adhesive layer (C) and the adhesive layer (D) from the viewpoint of productivity and optical properties.

<Method of Manufacturing Polarizing Plate with Adhesive Layer>

The polarizing plate produced by the above-described production method can be produced by bonding (k) such that the surface of the adhesive layer (F) provided on the release sheet is in contact with the exposed surface of the resin layer (E). The polarizing plate with an adhesive layer of the present invention.

Here, it is preferable that at least one layer, preferably all layers of the adhesive layer (C), the adhesive layer (D), and the adhesive layer (F) contain a polyfunctional active energy ray-curable compound and irradiate the active energy ray. As a polarizing plate with an adhesive layer.

The irradiation timing of the active energy ray may be performed after bonding the respective layers, and from the viewpoint of simplification of the step, it is preferred that the active energy ray is irradiated after the step (k). Alternatively, the active energy ray may be irradiated from above the hard coat layer (A), or from above the release sheet provided on the adhesive layer (F), or from either side of both sides. The type of the active energy ray, the irradiation conditions, and the like are as described above.

The polarizing plate of the present invention is used for liquid crystal cells in an LCD, and can be used as a light amount adjusting device, a polarizing interference application device, an optical defect detector, or the like.

[Examples]

Hereinafter, the present invention will be described in more detail based on the examples, but the present invention is not limited by these examples.

Further, regarding the evaluation sample I obtained in each example, the optical properties and the durability adhesion of the hard coat layer were evaluated by the following methods.

<Optical characteristics>

(1) Total light transmittance and haze

The measurement was carried out in accordance with JIS K 6714 using a haze meter "NDH 2000" manufactured by Nippon Denshoku Industries Co., Ltd.

(2) 60 ° C specular gloss

The measurement was carried out in accordance with JIS K 7105 using a haze meter "VG 2000" manufactured by Nippon Denshoku Industries Co., Ltd.

<durability adhesion>

The sample I for evaluation was allowed to stand under conditions of (A) 60 ° C, 90% RH, (B) 90 ° C, and (C) FOM (carbon arc (panel temperature: 60 ° C)) for 500 hours, and then evaluated by the following method. Durable adhesion of hard coatings.

(3) Durable adhesion of hard coating

In the above-mentioned environment, the sample I for evaluation was placed in a multi-blade cutting tool having six blades at intervals of 1 mm in the center portion thereof according to JIS K 5600-5-6, and a vertical and horizontal 1 mm square was formed in accordance with six vertical and horizontal directions. The base mesh was measured by laminating and peeling off an adhesive sheet having an adhesive force of 10 N/25 mm. As a result, evaluation was performed based on JIS K 5600-5-6 on the following basis.

0: The cutting edge is completely smooth and all square meshes are not peeled off.

1: The coating film at the intersection of the cut has a small degree of peeling. The amount of influence in the cross-cutting section is clearly no more than 5%.

2: The coating film is peeled off along the cutting edge and/or at the intersection. The portion affected in the cross-cutting section is clearly more than 5%, but not more than 15%.

3: A large-scale peeling of the coating film along the cutting edge occurs locally or over the entire surface, and/or partial or full-surface peeling occurs in various portions of the mesh. The portion affected in the cross-cut is clearly more than 15% but not more than 35%.

4: The hard coat layer is severely peeled off locally or over the entire surface along the cut edge, and/or the mesh is peeled off partially or over the entire surface. The amount of influence in the cross-cutting section is clearly no more than 35%.

5: Any of the degree of peeling that cannot be classified in Category 4.

(4) Determination of surface adhesion of polarizing film and adhesive layer (C)

Each of the polarizing plates obtained in Example 2 and Comparative Example 2 was cut into a sample of 25 mm×100 mm, and a tensile tester ("TENSILON" manufactured by ORIENTEC Co., Ltd.) was used according to the adhesion measuring method of JIS Z 0237, at a peeling speed of 300 mm. The surface adhesion was measured under the condition of /min and a peeling angle of 180 °C.

(5) Storage elastic modulus E' of the resin layer (B)

The resin layer of the Example (the triethylenesulfonated cellulose film in Comparative Example 1) was cut into 3 pieces each of a rectangular shape of 5 mm×30 mm to prepare a sample. According to JIS K7244-4, the dynamic elastic modulus E' (Pa) at 23 ° C of the sample was measured at 11 Hz using a dynamic viscoelasticity measuring device [manufactured by TA Instruments, device name "Q800DMA"], and each of the three points was measured. The average value is taken as the storage elastic modulus E'.

(6) Storage elastic modulus G' of the adhesive layer (C)

The adhesive material similar to that of the example was applied to the release layer of the release sheet [manufactured by Linde Co., Ltd., trade name "SP-PET381031"], and the film thickness after drying was 25 μm, and the adhesive layer obtained by drying was applied. The sheet was peeled off from the release sheet and laminated to a thickness of about 3 mm. The laminated adhesive layer was irradiated with ultraviolet rays (light amount: 250 mJ/cm ² ), and cut into a circular shape having a diameter of 8 mm to prepare a sample. According to JIS K7244-6, the storage elastic modulus G' (Pa) at 23 ° C of the sample was measured at 1 Hz using a viscoelasticity measuring device [manufactured by Rheometrics, Inc. (now TA Instruments), device name "DYNAMIC ANALYZER RDAII"]. .

(7) Determination of weight average molecular weight Mw and molecular weight distribution Mw/Mn

The (meth) acrylate copolymer of the resin layer and the adhesive layer of the examples was measured by gel permeation chromatography (GPC) under the following conditions, and the weight average molecular weight Mw and molecular weight distribution were calculated by polystyrene conversion. Mw / Mn.

(measurement conditions)

GPC measuring device: manufactured by TOSOH Co., Ltd., "HLC-8020"

GPC column (the following sequence is passed): manufactured by TOSOH Co., Ltd.

TSK guard column HXL-H

TSK gel GMHXL (X2)

TSK gel G2000HXL

Determination of solvent: tetrahydrofuran

Measuring temperature: 40 ° C

(8) Light leakage resistance

The polarizing plate with an adhesive layer obtained in Example 3 and Comparative Example 3 was adjusted to a size of 233 mm×309 mm by a cutting device [Supercutter “PN1-600” manufactured by Takino Seiki Co., Ltd.), and then bonded to an alkali-free glass. The autoclave manufactured by Kurihara Seisakusho Co., Ltd. was used, and it was pressurized at 0.5 MPa, 50 ° C, and 20 minutes. Further, in the above-described bonding, the polarizing plate with the adhesive is placed in a state in which the polarizing axis is in a state of being orthogonally polarized in the surface of the alkali-free glass. In this state, it was allowed to stand at 80 ° C for 200 hours. Then, it was allowed to stand in an environment of 23 ° C and a relative humidity of 50% for 2 hours, and the light leakage property was evaluated by the following method under the same environment.

The brightness of each area shown in Fig. 1 was measured using "MCPD-2000" manufactured by Otsuka Electronics Co., Ltd.

ΔL*=[(b+c+d+e)/4]-a

(wherein a, b, c, d, and e are the predetermined measurement points (the luminance of the central portion 1 of each region) of the A region, the B region, the C region, the D region, and the E region, respectively, and the luminance difference ΔL is obtained. * As light leakage. The smaller the value of ΔL*, the less light leakage is indicated.

Example 1

(1) Formation of resin layer (B)

As an engineering sheet, polymethyl methacrylate (same polymerization) was coated on a polyethylene terephthalate (PET) film (manufactured by Mitsubishi Resin Co., Ltd., registered trademark "DIAFOIL T100 TYPE") having a thickness of 50 μm. a product having a weight average molecular weight of Mw=200,000, a molecular weight distribution Mw/Mn=about 2.3, a storage elastic modulus of the dried coating film at 23° C. E′=5 MPa, and a concentration of 25% by mass of ethyl acetate, after drying The thickness was 30 μm, and drying treatment was performed at 100 ° C for 1 minute to form a resin layer made of polymethyl methacrylate.

(2) Formation of hard coat layer

On the resin layer formed in the above (1), a hard coat agent (manufactured by Linda Co., Ltd., trade name "AGT-100"), and a propylene glycol monomethyl ether (PGM) solution having a concentration of 40% by mass of an acrylic compound was applied. The thickness after drying was 7 μm, and after drying, ultraviolet rays were irradiated with a light amount of 250 mJ/cm ² to form a hard coat layer. A protective film having a thickness of 50 μm was adhered to the surface of the hard coat layer (manufactured by Linde Co., Ltd., trade name "SPF/AlA", manufactured by PET].

(3) Production of adhesive layer (C) with release sheet

An adhesive material having the following composition was applied to a release layer of a PET release sheet having a thickness of 38 μm (manufactured by Linde Co., Ltd., trade name "SP-PET381031") to have a thickness of 10 μm after drying, and then, It was dried by heating to prepare an adhesive layer with a release sheet. Further, in order to produce a sample for storing the modulus of elasticity measurement, an adhesive layer having a release sheet was produced in the same manner as above, and the ultraviolet ray was irradiated with a light amount of 250 mJ/cm ² . The storage elastic modulus G' at 23 ° C of the adhesive layer irradiated with ultraviolet rays was measured and found to be 0.6 MPa.

<Composition of adhesive materials>

100 parts by mass of an acrylic copolymer (weight average molecular weight Mw: 800,000) having a mass ratio of butyl acrylate/methyl acrylate/acrylic acid of 77/20/3

Tris(acryloxyethyl)isomeric cyanurate as an ultraviolet curable polyfunctional acrylate [manufactured by Toagosei Co., Ltd., trade name "ARONIX M-315", molecular weight 578] 25 parts by mass

a mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone as a photopolymerization initiator in a mass ratio of 1:1 [manufactured by Ciba Specialty Chemicals Co., Ltd., trade name "IRGACURE 500"] 1 part by mass

Trimethylolpropane-modified benzylidene diisocyanate as an isocyanate-based crosslinking agent [manufactured by Japan POLYURETHANE Co., Ltd., trade name "CORONATE L"] 2 parts by mass

(4) Production of optical protective film

The work piece of the resin layer (B) having the hard coat layer on the surface of the work piece obtained in the above (2) is peeled off, and the surface on the opposite side to the hard coat layer of the resin layer (B) is exposed, according to adhesion. The adhesive layer (C) with a release sheet obtained in the above (3) was bonded to the exposed surface to form an optical protective film.

(5) Preparation and evaluation of sample I for evaluation

The surface of the release sheet of the laminated film obtained in the above (4) was irradiated with ultraviolet light at a light amount of 250 mJ/cm ² , and then cut into 150 mm×100 mm, and the release sheet was peeled off and adhered to a glass plate to prepare a sample for evaluation I. .

For the sample I for evaluation, the optical properties and the durability of the hard coat layer were evaluated.

Example 2

(1) Production of polarizing film

A polyvinyl alcohol-based film [manufactured by Nippon Synthetic Chemical Co., Ltd., trade name "NIHON VINYLON"] was placed in an aqueous solution of 30 ° C made of 1000 parts by mass of water, 10 parts by mass of iodine, and 100 parts by mass of potassium iodide, and impregnated 3 In minutes, the iodine is dyed and adsorbed. Next, the immersed film was immersed in a 5 mass% boric acid aqueous solution at 50 ° C, and uniaxially stretched 6 times in the longitudinal direction of the film. The immersion time in the aqueous boric acid solution in this process was 5 minutes. The film taken out from the aqueous boric acid solution was kept in a uniaxially stretched state, placed in water at 20 ° C, immersed for 5 minutes for washing, and then dried, thereby obtaining a polarizing film.

(2) Production of polarizing plate

The release sheet of the optical protective film obtained in Example 1 (4) was peeled off, and the exposed surface of the adhesive layer (C) was bonded to one surface of the polarizing film.

On the other hand, according to the adhesive layer (D) obtained with the release sheet obtained in Example 1 (3), the side of the adhesive layer (D) on which the release sheet is not provided, and The resin layer (B) obtained in the same manner as in the resin layer (B) obtained in the first embodiment (1) was bonded to each other to form a laminated film.

Then, the release sheet on the adhesive layer (D) of the laminated film is peeled off, and the adhesive layer (D) is bonded to the other surface of the polarizing film to obtain a hard coat layer (A)/resin. A structure such as a layer (B) / an adhesive layer (C) / a polarizing film / an adhesive layer (D) / a resin layer (E) / an engineering film.

The autoclave produced by Kurihara Seisakusho Co., Ltd. was pressed under conditions of 0.5 MPa and 50 ° C for 20 minutes to adhere thereto, and ultraviolet rays (light amount: 250 mJ/cm ² ) were irradiated from both surfaces of the structure. Make a polarizer.

Example 3

(1) Fabrication of a polarizing plate with an adhesive layer

The engineered film of the polarizing plate obtained in Example 2 was peeled off, and the adhesive layer (F) obtained in the same manner as the pressure-sensitive adhesive layer (C) having the release sheet of Example 1 (3) was not peeled off. The adhesive layer on one side of the sheet is attached to the exposed surface to obtain a hard coat layer (A)/resin layer (B)/adhesive layer (C)/polarizing film/adhesive layer (D)/ A structure composed of a resin layer (E)/adhesive layer (F)/release sheet. Ultraviolet rays (light amount: 250 mJ/cm ² ) were irradiated from the side of the release sheet of the structure to prepare a polarizing plate with an adhesive layer.

Comparative example 1

In place of the resin layer (B) of Example 1, except that a triethyl fluorene-based cellulose film [Fuji Film Co., Ltd., trade name "TD80UL" was used, and a hard coat agent was applied on the B (ribbon) side)] A protective film for optics was obtained in the same manner as in Example 1 except for the operation.

Comparative example 2

(1) Production of polarizing plate

The release sheet of the adhesive layer (C) of the optical protective film obtained in Comparative Example 1 was peeled off, and the exposed adhesive layer was bonded to one surface of the polarizing film produced in Example 2 (1).

On the other hand, according to the adhesive layer (D) obtained in the same manner as in the adhesive layer (C) obtained in Example 1 (3), the side of the peeling sheet on which the adhesive sheet having the release sheet was not provided was provided. The film was bonded to the B (ribbon) surface of the triacetyl cellulose film used in Comparative Example 1, thereby producing a laminated film.

Next, the release sheet on the adhesive layer (D) of the laminated film is peeled off, and the adhesive layer (D) is bonded to the other surface of the polarizing film to obtain a hard coat layer (A)/TAC. A structure such as a film/adhesive layer (C)/polarizing film/adhesive layer (D)/TAC film/engineered film.

The autoclave produced by Kurihara Seisakusho Co., Ltd. was pressed under conditions of 0.5 MPa and 50 ° C for 20 minutes to adhere thereto, and ultraviolet rays (light amount: 250 mJ/cm ² ) were irradiated from both surfaces of the structure. Make a polarizer.

Comparative example 3

(1) Fabrication of a polarizing plate with an adhesive layer

The engineered film of the polarizing plate obtained in Comparative Example 2 was peeled off, and the adhesive layer (F) with the release sheet obtained in the same manner as the adhesive layer (C) of Example 1 (3) was not peeled off. The adhesive layer (F) on one side of the sheet is attached to the exposed surface to obtain a hard coat layer (A)/TAC film/adhesive layer (C)/polarizing film/adhesive layer (D). / TAC film / adhesive layer (F) / release sheet structure. Ultraviolet rays (light amount: 250 mJ/cm ² ) were irradiated from the side of the release sheet of the structure to prepare a polarizing plate with an adhesive layer.

Various evaluations shown in Table 1 were performed on the obtained optical protective film, polarizing plate, and polarizing plate with an adhesive layer of the Example and the comparative example obtained.

The evaluation results of Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1.

* Due to the destruction of the resin layer, it is practically impossible to measure.

As is clear from Table 1, the optical protective film of Example 1 of the present invention has the same optical characteristics as the optical protective film of the TAC film of Comparative Example 1, and is superior to the TAC film in terms of durability of the hard coat layer. The optical protective film is superior.

Moreover, it was found that the polarizing film and the adhesive layer had sufficient sealing properties by the test of the surface adhesion of the polarizing plate of Example 2 produced using the optical protective film of Example 1. It is also known that the polarizing plate with an adhesive layer of Example 3 produced using the polarizing plate of Example 2 has excellent light leakage resistance as compared with the polarizing plate with an adhesive layer of Comparative Example 3.

Industrial utilization possibility

The optical protective film of the present invention has a hard coat function, is excellent in transparency, is optically isotropic, has good heat resistance and moisture resistance, is excellent in durability, and has good sealing properties against a polyvinyl alcohol-based polarizing film. It is suitable for use as, for example, a polarizing plate or a quarter-wave plate in a liquid crystal display device, or a protective film for a touch panel, a disc, a protective film for various displays, etc., and is particularly suitable for use as a polarizing plate.

Fig. 1 is an explanatory view showing a method of evaluating light leakage resistance of a polarizing plate with an adhesive layer obtained in Examples and Comparative Examples.

Claims (13)

A protective film for optics, which is a laminated film formed by sequentially laminating a hard coat layer (A), a resin layer (B), and an adhesive layer (C), characterized in that the resin layer (B) contains 80 a (meth) acrylate compound having a weight average molecular weight of 100,000 to 500,000 and a molecular weight distribution of 1.5 to 3.0; the hard coat layer (A) containing an active energy ray for irradiating the active energy ray-sensitive composition a cured product; the adhesive layer (C) comprising a cured product formed by irradiating an active energy ray to the polyfunctional active energy ray-curable compound; the hard coat layer (A) and the adhesive layer (C) The content of the (meth) acrylate-based compound in one layer is 80% by mass or more. The optical protective film according to claim 1, wherein the resin layer (B) has a storage elastic modulus E' at a temperature of 23 ° C of 0.5 MPa or more. The optical protective film according to claim 1 or 2, wherein the adhesive layer (C) has a storage elastic modulus G' of 0.3 MPa or more at a temperature of 23 ° C after the irradiation of the active energy ray. A method for producing an optical protective film according to any one of claims 1 to 3, characterized by comprising: (a) a step of forming a resin layer (B) by casting on one side of the engineering sheet; (b) a step of forming a hard coat layer (A) on the resin layer (B); and (c) peeling off the above-mentioned engineering sheet, and bonding an adhesive layer provided on the release sheet on the exposed resin layer (B) surface (C) The step of bonding to the surface. The method for producing an optical protective film according to the fourth aspect of the invention, wherein the hard coat layer of the step (b) is formed by irradiating an active energy ray-sensitive composition layer with an active energy ray. A polarizing plate obtained by laminating a polarizing film and a surface of an adhesive layer (C) of an optical protective film according to any one of claims 1 to 3 of the invention. A polarizing plate characterized in that a polarizing film is laminated on an adhesive layer (C) surface of an optical protective film according to any one of claims 1 to 3, and further laminated on the polarizing film On the other side, the adhesive layer (D) and the resin layer (E) are laminated in this order, and each of the layers (D) and (E) is a layer containing 80% by mass or more of a (meth) acrylate-based compound. Constituted. A polarizing plate with an adhesive layer, further comprising an adhesive layer (F) on the exposed side of the resin layer (E) of the polarizing plate of claim 7 of the patent application, the adhesive layer (F) ) 80% by mass or more of a (meth) acrylate-based compound. A method for producing a polarizing plate according to claim 7 of the invention, characterized in that: (a) a step of forming a resin layer (B) by casting on one side of the engineering sheet; (b) a step of forming the resin layer ( B) a step of forming a hard coat layer (A) thereon; (c) a step of peeling the above-mentioned engineering sheet and bonding the surface of the adhesive layer (C) provided on the release sheet to the exposed resin layer (B) to be bonded And (d) peeling off the peeling sheet, and sticking the exposed adhesive layer (C) a step of bonding to one surface of the polarizing film; (e) a step of forming a resin layer (E) by casting on one side of the other engineering sheet; and (f) peeling off the resin layer (E) a step of bonding the surfaces on the exposed side of the adhesive layer (D) provided on the sheet, and (g) peeling off the peeling sheet of the adhesive layer (D) and bonding the polarized light to the polarized light The step on the other side of the membrane. The method for producing a polarizing plate according to claim 9, wherein in the step (b), the hard coat layer (A) is formed by irradiating an active energy ray-sensitive composition layer with an active energy ray. The method for producing a polarizing plate according to claim 9 or 10, wherein the adhesive layer (C) and/or the adhesive layer (D) contains a polyfunctional active energy ray-curable compound, and has (h) the above steps (g) a step of irradiating the active energy ray afterwards. A method for producing a polarizing plate with an adhesive layer, characterized by having (k) an exposed surface on the above resin layer (E) by a polarizing plate obtained according to claim 9 or 10 The step of bonding is performed by bonding the surface of the adhesive layer (F) provided on the release sheet. The method for producing a polarizing plate with an adhesive layer according to claim 12, wherein at least one of the adhesive layer (C), the adhesive layer (D) and the adhesive layer (F) contains a polyfunctional active energy ray A hardening type compound, and having (1) a step of irradiating an active energy ray after the above step (k).