JP6492522B2 - Laminated body and polarizing plate - Google Patents

Description

  The present invention relates to a film, and more particularly to a film that can be suitably used as a protective film for protecting a polarizing film used in a liquid crystal display. The present invention also relates to a polarizing plate using the film and a liquid crystal display device having the polarizing plate.

  In recent years, liquid crystal displays have been widely used as display devices for televisions, personal computers, digital cameras, mobile phones and the like. The liquid crystal display has a configuration of front side polarizing plate / liquid crystal / rear side polarizing plate, where the display side is the front side and the opposite side (backlight side) is the rear side. The polarizing plate is usually formed by laminating a protective film or the like on a polarizing film made of a dyed uniaxially stretched polyvinyl alcohol film, for example, a laminated film of protective film / polarizing film / protective film. The protective films disposed on the front and rear surfaces of the polarizing film constituting the front polarizing plate are designated as protective film A and protective film B, respectively, and the protective films disposed on the front and rear surfaces of the polarizing film constituting the rear polarizing plate. Assuming that the film is a protective film C and a protective film D, respectively, the overall configuration is protective film A / front side polarizing film / protective film B / liquid crystal / protective film C / rear side polarizing film / protective film D from the front side. It becomes.

  Conventionally, as a protective film, since it has high transparency and optical isotropy, a triacetyl cellulose film (hereinafter sometimes abbreviated as a TAC film) is often used.

However, since the TAC film is inferior in dimensional stability and heat-and-moisture resistance, it causes problems such as generation of stress accompanying shrinkage and deterioration of the function of the polarizer, and affects the image quality of the liquid crystal display device using this polarizing plate. It was. Further, the TAC film has a drawback that the surface must be saponified with an alkaline solution in advance in order to adhere to the polarizing film.
As liquid crystal displays increase in size and quality in recent years, improvement in mechanical strength and stability under high-temperature and high-humidity environments is required. The need to avoid quality degradation has emerged. Furthermore, since the alkali treatment uses a high-concentration alkaline solution, it is not preferable in terms of work safety and environmental protection.

In order to solve these problems, studies as described below have been made using a polycarbonate resin having excellent dimensional stability and heat and moisture resistance.
For example, a polarizer protective film comprising a thermoplastic polymer film such as a polycarbonate resin coated on at least one side with a mixture containing a hydrophilic polymer compound and a crosslinkable resin compound, and then heat-treated. A manufacturing method is disclosed (Patent Document 1). However, this method usually has a problem that it takes several minutes to cure by heat treatment, and the process time becomes long, and deformation and shrinkage of the film by heat treatment occur.

  On the other hand, after forming a cross-linked resin cured layer on one side of a specific transparent plastic synthetic polymer film represented by polycarbonate resin, a thin layer made of a hydrophilic polymer compound is formed on the outermost surface by a wet coating method. A method for producing a protective film for a polarizing plate by drying the solvent is disclosed (Patent Document 2). However, this method has problems such as insufficient adhesion, a hydrophilic polymer compound with poor wettability, which is easy to repel, and a longer process time depending on the time for drying the solvent.

JP 2007-263388 A JP 2005-266463 A

  The present invention has been made in view of the above circumstances, and the problem to be solved is a coat layer that can solve various problems of a TAC film and can be satisfactorily adhered to a polarizing film in a short time. Further, the present invention provides a film that has a high total light transmittance and can be suitably used as a protective film for a polarizing film, and a polarizing plate and a liquid crystal display device using the film.

  As a result of intensive studies in view of the above circumstances, the present inventors have found that the use of a film having a specific configuration can easily solve the above-described problems, and have completed the present invention.

That is, according to the first aspect of the present invention, on at least one surface of the polycarbonate layer mainly composed of Po polycarbonate resin, the composition containing no contain acrylate cyclic imine compounds having one or more hydroxyl groups A laminate having a coating layer and including a water-based adhesive layer on the coating layer is provided.
According to a second invention of the present invention, in the first invention, the polycarbonate resin is a polycarbonate resin containing a structural unit derived from a dihydroxy compound represented by the following formula (1). A laminated body is provided.

According to a third aspect of the present invention, there is provided a laminate according to the first or second aspect , wherein the acrylate is a monofunctional acrylate and / or a bifunctional acrylate.

According to the fourth invention of the present invention, in any one of the first to third inventions, the polycarbonate resin further comprises a structural unit derived from tricyclodecane dimethanol represented by the following formula (2). The laminated body characterized by containing is provided.

Furthermore, according to a fifth aspect of the present invention, there is provided a laminate according to any one of the first to fourth aspects, wherein the composition contains a photopolymerization initiator.
According to the sixth aspect of the present invention, in any one of the first to fifth aspects, the relationship between the film thickness (t1) of the polycarbonate layer and the film thickness (t2) of the coat layer is 1 ≦ There is provided a laminate having t1 / t2 ≦ 1000.

Furthermore, according to the seventh aspect of the present invention, there is provided a laminate according to any one of the first to sixth aspects, wherein the coating layer has a thickness of 0.1 to 10 μm. .

According to an eighth aspect of the present invention, there is provided a polarizing plate comprising a polarizing film adhered to the coat layer of the laminate according to any one of the first to seventh aspects via the aqueous adhesive layer. Provided .

According to the ninth aspect of the present invention, there is provided a liquid crystal display device having the polarizing plate according to the eighth aspect .

  According to the film of the present invention, it is possible to form a coat layer having a good adhesive force with an adhesive for adhering a polarizing film in a short time, and the film itself is highly transparent and is used as a polarizing plate. It is possible to provide a film having excellent total light transmittance, and its industrial value is high.

1. Polycarbonate Layer The polycarbonate layer used in the film of the present invention (hereinafter sometimes referred to as “the polycarbonate layer of the present invention” or “polycarbonate film”) contains a polycarbonate resin as a main component. Here, the main component means that the component in the layer is preferably 50% by weight or more, more preferably 80% by weight or more, and still more preferably 90% by weight or more. The polycarbonate layer may have a single-layer configuration or a multilayer configuration. In the case of a multilayer configuration, the multilayer of four or more layers may be used as long as it does not exceed the gist of the present invention other than the two-layer configuration and the three-layer configuration. There is no particular limitation.

  A typical example of the polycarbonate resin is an aromatic polycarbonate having 2,2′-bis (4-hydroxyphenyl) -propane (commonly referred to as bisphenol-A) as a structural unit. The polycarbonate resin used in the present invention. Is not limited thereto, for example, 1,1-bis (4-hydroxyphenyl) -alkylcycloalkane, 1,1-bis (3-substituted-4-hydroxyphenyl) -alkylcycloalkane, 1, Monomer component containing at least one dihydric phenol selected from the group consisting of 1-bis (3,5-substituted-4-hydroxyphenyl) -alkylcycloalkane and 9,9-bis (4-hydroxyphenyl) fluorenes Homo or copolymer polycarbonate, dihydric phenol and bisphenol A A mixture of polycarbonate and Nomar components, such as copolycarbonate the above dihydric phenol and the bisphenol A monomers components.

  As the polycarbonate resin used in the polycarbonate layer of the present invention, a dihydroxy compound having a site represented by the following formula (1) in a part of the structure from the viewpoint of high transparency, high strength, high heat resistance, high weather resistance, etc. Polycarbonate resins containing structural units derived from are preferred.

  More specifically, examples of the dihydroxy compound represented by the above formula (1) include isosorbide, isomannide and isoidet which are in a stereoisomeric relationship.

  The dihydroxy compound represented by the formula (1) is an ether diol that can be produced from a saccharide using a biogenic material as a raw material. In particular, isosorbide can be produced at low cost by hydrogenating and then dehydrating D-glucose obtained from starch, and can be obtained in abundant resources. Under these circumstances, isosorbide is most preferable as the dihydroxy compound represented by the above formula (1).

  The polycarbonate resin may further contain a structural unit other than the structural unit derived from the dihydroxy compound having the site represented by the formula (1). By further including a structural unit other than the structural unit derived from the dihydroxy compound having the site represented by the formula (1), it becomes possible to improve processability and impact resistance.

  Of the structural units other than the structural unit derived from the dihydroxy compound having the site represented by the formula (1), a structural unit derived from a dihydroxy compound having no aromatic ring is preferably used.

  More specifically, for example, structural units derived from aliphatic dihydroxy compounds described in International Publication No. 2004/111106 and structural units derived from alicyclic dihydroxy compounds described in International Publication No. 2007/148604. it can.

  Among the structural units derived from the aliphatic dihydroxy compound, at least one selected from ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol. It preferably contains a structural unit derived from a dihydroxy compound.

  Among the structural units derived from the alicyclic dihydroxy compound, those containing a 5-membered ring structure or a 6-membered ring structure are preferable. The six-membered ring structure may be fixed in a chair shape or a boat shape by a covalent bond.

  By including a structural unit derived from an alicyclic dihydroxy compound having a 5-membered ring structure or a 6-membered ring structure, the heat resistance of the obtained polycarbonate resin can be increased.

  The number of carbon atoms contained in the alicyclic dihydroxy compound is usually preferably 70 or less, more preferably 50 or less, and further preferably 30 or less.

Examples of the alicyclic dihydroxy compound containing the 5-membered ring structure or the 6-membered ring structure include those described in the above-mentioned International Publication No. 2007/148604.
Among these, cyclohexane dimethanol, tricyclodecane dimethanol, adamantanediol, and pentacyclopentadecane dimethanol can be preferably exemplified. Among these, cyclohexane dimethanol or tricyclodecane dimethanol is more preferable in view of economy and heat resistance. In particular, it is most preferable to contain a structural unit derived from tricyclodecane dimethanol represented by the following formula (2) from the viewpoint of balance between economic efficiency, heat resistance and optical properties.
In addition, these other structural units may contain only 1 type in polycarbonate resin, and may contain 2 or more types.

The content ratio of the structural unit derived from the dihydroxy compound having the site represented by the formula (1) in a part of the structure of the polycarbonate resin is based on the structural unit derived from all the dihydroxy compounds in the polycarbonate resin. It is preferably 30 mol% or more, more preferably 40 mol% or more, particularly preferably 50 mol% or more, and preferably 90 mol% or less, more preferably 80 mol% or less.
If the content ratio of the structural unit derived from the dihydroxy compound having the site represented by the formula (1) in a part of the structure of the polycarbonate resin is equal to or higher than the lower limit, the heat resistance is improved by maintaining the glass transition temperature. Is preferable. On the other hand, by being below the upper limit, coloring derived from a carbonate structure, coloring derived from impurities contained in a trace amount because a biogenic substance is used as a raw material, etc. can be suppressed, and transparency usually required for a polycarbonate layer There is a possibility not to impair the sex. In addition, appropriate molding processability, mechanical strength and heat resistance, which are difficult to achieve with a polycarbonate resin composed only of structural units derived from a dihydroxy compound having a site represented by the above formula (1) in part of the structure You can balance gender.

  The polycarbonate resin includes a structural unit derived from a dihydroxy compound having a site represented by the formula (1) in a part of the structure, and a structural unit derived from an aliphatic dihydroxy compound and / or an alicyclic dihydroxy compound. Although it is preferable to consist of derived structural units, structural units derived from other dihydroxy compounds may be further included within the range not impairing the object of the present invention.

  The polycarbonate resin can be produced by a generally used polymerization method. The polycarbonate resin may be produced by either a phosgene method or a transesterification method in which it is reacted with a carbonic acid diester. Among them, in the presence of a polymerization catalyst, a dihydroxy compound having a site represented by the above formula (1) in a part of the structure, an aliphatic and / or alicyclic dihydroxy compound, and other used as necessary A transesterification method in which the dihydroxy compound is reacted with a carbonic acid diester is preferred.

  The transesterification method includes one or more dihydroxy compounds having a site represented by the formula (1) in a part of the structure and one or more aliphatic and / or alicyclic dihydroxy compounds. In addition, one or two or more other dihydroxy compounds used as necessary and a carbonic acid diester are added with a basic catalyst, and further, an acidic substance that neutralizes the basic catalyst is added to carry out a transesterification reaction. It is a manufacturing method to be performed.

  Representative examples of carbonic acid diesters include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (biphenyl) carbonate, diethyl carbonate, dimethyl carbonate, dibutyl carbonate, and dicyclohexyl carbonate. Is mentioned. These may be used alone or in combination of two or more. Of these, diphenyl carbonate is particularly preferably used.

The molecular weight of the polycarbonate resin used in the present invention can be represented by a reduced viscosity, and the lower limit of the reduced viscosity is preferably 0.20 dl / g or more, more preferably 0.30 dL / g or more, and 0.35 dL / g or more. More preferably, the upper limit of the reduced viscosity is preferably 2.00 dL / g or less.
If the reduced viscosity of the polycarbonate resin is too low, the mechanical strength of the molded product may be small. If it is too large, the fluidity at the time of molding tends to decrease, and the productivity and moldability tend to decrease.

The reduced viscosity of the polycarbonate resin is precisely adjusted so that the concentration of the polycarbonate resin is 0.60 g / dl using an Ubbelohde viscometer with a DT-504 type automatic viscometer manufactured by Chuo Rika Co., Ltd. After the adjustment, the temperature is calculated from the measured value based on the following at a temperature of 20.0 ° C. ± 0.1 ° C.
From the passage time t _{0 of the} solvent and the passage time t of the solution, the following formula:
η _rel = t / t ₀
More seek relative viscosity eta _rel, from the relative viscosity eta _rel, the formula:
η _sp = (η−η ₀ ) / η ₀ = η _rel −1
Further, the specific viscosity ηsp is determined.
By dividing the specific viscosity η _sp by the concentration c (g / dl), the following formula:
η _red = η _sp / c
From this, the reduced viscosity (converted viscosity) η _red is determined.

  An ultraviolet absorber may be added to the polycarbonate layer of the present invention. As the ultraviolet absorber added to the polycarbonate layer, known ones such as various commercially available ones can be used without particular limitation. Especially, what is normally used for the addition to well-known aromatic polycarbonate resin can be used conveniently.

  Examples of the ultraviolet absorber include 2- (2′-hydroxy-5′-tert-octylphenyl) benzotriazole and 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzo. Triazole, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole and 2,2′- Benzotriazole ultraviolet absorbers such as methylenebis (4-cumyl-6-benzotriazolephenyl); benzoxazine ultraviolet absorbers such as 2,2′-p-phenylenebis (1,3-benzoxazin-4-one) 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyl) oxy-fe; And hydroxyphenyltriazine-based ultraviolet absorbers such as knoll;

  The melting point of the ultraviolet absorber is particularly preferably in the range of 120 ° C to 250 ° C. When using a UV absorber with a melting point of 120 ° C. or higher, the film surface becomes dirty due to a bleed-out phenomenon in which the UV absorber aggregates on the film surface over time, or when forming a film using a die or a metal roll, Bleed-out prevents them from becoming dirty and reduces and improves film surface haze.

  From these viewpoints, as the ultraviolet absorber, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl)- 5-chlorobenzotriazole, 2- [2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″, 6 ″ -tetrahydrophthalimidomethyl) -5′-methylphenyl] benzotriazole, 2,2-methylenebis [ 4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl)] phenol and 2- (2-hydroxy-3,5-dicumylphenyl) benzotriazole Benzotriazole ultraviolet absorbers and 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyl) oxy-fe It can be preferably used hydroxyphenyl triazine-based UV absorbers such Lumpur.

Among these, 2- (2-hydroxy-3,5-dicumylphenyl) benzotriazole, 2,2-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzo Triazol-2-yl)] phenol, 2- (4,6-diphenyl-1,3, -triazin-2-yl) -5- (hexyl) oxy-phenol are particularly preferred.
These ultraviolet absorbers may be used alone or in combination of two or more.

The UV absorber is preferably added in a proportion of 0.0001 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the polycarbonate resin, and is added in a proportion of 0.0005 parts by weight or more and 15 parts by weight or less. More preferably, it is more preferably added in a proportion of 0.001 part by weight or more and 10 parts by weight or less.
By adding the ultraviolet absorber in such a range, the weather resistance of the film of the present invention can be improved without causing bleeding of the ultraviolet absorber to the surface of the polycarbonate layer and deterioration of the mechanical properties of the polycarbonate layer.

  As long as the object of the present invention is not impaired, the polycarbonate layer is also added with an appropriate amount of other various additives such as a silane coupling agent, an antioxidant and a weathering stabilizer as an additive component other than the ultraviolet absorber. May be. Moreover, you may add resin other than polycarbonate resin in the range which does not impair the objective of this invention.

  The film thickness of the polycarbonate layer is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less from the viewpoint of thinning the film of the present invention and the polarizing plate of the present invention using the film. From the viewpoint of mechanical strength, it is preferably 3 μm or more, more preferably 5 μm or more, and further preferably 10 μm or more.

As a method for forming a polycarbonate film to be a polycarbonate layer of the present invention, a known method, for example, extrusion casting using a T-die having a melt mixing facility such as a single screw extruder, a multi-screw extruder, a Banbury mixer, a kneader, etc. A method such as a calendering method or a calendering method can be employed, and although not particularly limited, in the present invention, an extrusion casting method using a T-die is preferably used in terms of handling properties and productivity. The molding temperature in the extrusion casting method using a T-die is appropriately adjusted depending on the flow characteristics and film forming properties of the polycarbonate resin to be used, but is generally 80 ° C. or higher, preferably 100 ° C. or higher, more preferably 120 ° C. or higher. Preferably, the temperature is 140 ° C. or higher, and is generally 320 ° C. or lower, preferably 300 ° C. or lower, more preferably 280 ° C. or lower, more preferably 260 ° C. or lower. When a silane coupling agent or the like is added, the reaction is accompanied. In order to suppress an increase in resin pressure and an increase in fish eye, it is preferable to lower the molding temperature. Various additives such as silane coupling agents, antioxidants, UV absorbers, and weathering stabilizers may be dry blended together with the polycarbonate resin and then supplied to the hopper. Pellets may be supplied after melting and mixing, or a master batch in which only the additive is concentrated in advance in a resin such as polycarbonate resin may be supplied.
The polycarbonate layer of the present invention may be subjected to a surface treatment such as a corona treatment or a plasma treatment in order to enhance adhesion with an acrylic coating layer described later.

2. Acrylic Coat Layer Next, a coating layer of a composition containing an acrylate having one or more hydroxyl groups in the present invention (hereinafter sometimes referred to as “acrylic coating layer”) will be described.
In the present invention, it is an essential requirement to form an acrylic coat layer on at least one surface of a polycarbonate layer containing a polycarbonate resin as a main component.
In the present invention, the general term “acrylate” includes “acrylate” and “methacrylate”.

The composition forming the acrylic coating layer used in the film of the present invention contains an acrylate having one or more hydroxyl groups (hereinafter, may be referred to as “specific acrylate”).
The acrylic coat layer may have a single layer structure or a multilayer structure. In the case of a multilayer structure, the multilayer structure of four layers or more is applicable as long as the gist of the present invention is not exceeded other than the two-layer or three-layer structure. There is no particular limitation.

The acrylic coating layer according to the present invention is a coating layer for improving the adhesiveness with various functional layers. For example, the adhesiveness between the polarizing film and various adhesives used for laminating the film of the present invention. It is formed in order to improve.
That is, the present inventors have examined the combination of various materials for improving the adhesion between the polycarbonate layer and the polarizing film adhesive, and can improve the adhesion by using a specific acrylate. It was possible to form a coating layer excellent in adhesiveness for protecting the polarizing film.

  More specifically, the acrylic coat layer is formed as an acrylic resin layer by applying a composition containing a specific acrylate to at least one surface of the polycarbonate layer of the present invention, followed by polymerization and curing.

Certain acrylates used in the present invention are characterized by having at least one hydroxyl group. The specific acrylate may have at least one hydroxyl group and may have two or more hydroxyl groups. However, from the viewpoints of wettability of the acrylate with respect to the polycarbonate film at the time of application, hygroscopicity after curing, etc., the specific acrylate preferably has 1 to 2 hydroxyl groups.
Since the specific acrylate has a hydroxyl group, it has a high affinity with a polycarbonate film and a water-based adhesive described later. Therefore, by using the specific acrylate for forming the acrylic coat layer, high adhesion can be obtained. .

  Examples of specific acrylates used in the present invention include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxy-1,1-dimethylethyl ( Monofunctional hydroxyalkyl such as (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydodecyl (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate Monoacrylate, 2-hydroxy-3- (meth) acrylpropyl (meth) acrylate, bifunctional hydroxydiacrylates such as 2-hydroxy-1,3-di (meth) acryloxypropane, pentaerythritol tri (me ) Hydroxypolyacrylates that are polyfunctional acrylates such as acrylate and dipentaerythritol poly (meth) acrylate, N- (hydroxymethyl) (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, N- N- (hydroxyalkyl) acrylamides such as (2-hydroxypropyl) (meth) acrylamide, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy-3-t-butylphenoxypropyl (meth) acrylate, Aromatic hydroxy acrylates such as 2-hydroxy-3-phenyl polyethylene glycol propyl (meth) acrylate may be mentioned. These may be used alone or in combination of two or more.

  The specific acrylate used in the present invention is preferably a monofunctional or bifunctional acrylate among the above acrylates. In the case of a monofunctional or bifunctional acrylate, the affinity with a polycarbonate film or water-based adhesive is increased, and there is a poor appearance such as undulation of the film or curling of the edge due to shrinkage stress generated at the time of curing. Hard to happen. Of these, bifunctional acrylates are more preferable. If it is a bifunctional acrylate, it becomes possible to obtain a film having an excellent balance between appearance characteristics and heat resistance.

  In the present invention, a composition containing a specific acrylate for forming an acrylic coat layer (hereinafter sometimes referred to as “acrylic coating composition”) is used to effectively obtain the above-described effects of the specific acrylate. The specific acrylate is preferably contained in an amount of 20% by weight or more, more preferably 30% by weight or more, and further preferably 40% by weight or more based on the solid content in the acrylic coating composition. Here, solid content refers to all components other than the solvent in the composition.

  The content of the specific acrylate in the acrylic coating composition is not particularly limited, and the acrylic coating composition may contain only the above specific acrylate as the acrylate in the composition, A specific acrylate and an acrylate other than the specific acrylate, that is, an acrylate having no hydroxyl group may be included.

  When the acrylic coating composition contains another acrylate other than the specific acrylate, the other acrylate is not particularly limited, but the acrylate having a structural unit derived from a trihydric or higher polyhydric alcohol is a polycarbonate layer. It is preferable for improving the adhesion between the polarizing plate and the adhesive for polarizing film adhesion.

  Examples of acrylates having structural units derived from trihydric or higher polyhydric alcohols include pentaerythritol tri (meth) acrylate, ethoxylated pentaerythritol tri (meth) acrylate, and propoxylated pentaerythritol tri (meth) acrylate. Erythritol acrylate, sorbitol tri (meth) acrylate, sorbitol tetra (meth) acrylate, sorbitol acrylate such as sorbitol penta (meth) acrylate, glucose acrylate such as glucose tri (meth) acrylate, mannitol tri (meth) acrylate, mannitol A polyhydric alcohol such as mannitol acrylate, such as tetra (meth) acrylate, esterified with acrylic acid or methacrylic acid , And the like that is ring-opening addition of the epoxy group of glycidyl acrylate to these terminal hydroxyl group. These may be used alone or in combination of two or more.

  When the acrylic coating composition contains other acrylates other than the specific acrylate, in order to effectively obtain the above-described effect by the specific acrylate and to obtain the blending effect of the other acrylate, the content of the other acrylate Is preferably 1 to 80 parts by weight based on 100 parts by weight of the total acrylate in the acrylic coating composition.

The acrylic coating composition preferably contains a photopolymerization initiator.
The photopolymerization initiator added to the acrylic coating composition is one that initiates a polymerization reaction by generating radicals, cationic species, or Lewis acids by active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams. Any known one can be used without particular limitation.

  Examples of radical generating compounds include 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4- Chlorobenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane -1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, hexaarylbiimidazole, bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide and the like.

Examples of compounds that generate cationic species and Lewis acids include aromatic diazonium salts such as benzenediazonium hexafluoroantimonate, benzenediazonium hexafluorophosphate, and benzenediazonium hexafluoroborate, diphenyliodonium tetrakis (pentafluorophenyl) borate, and diphenyliodonium. Aromatic iodonium salts such as hexafluorophosphate, diphenyliodonium hexafluoroantimonate, di (4-nonylphenyl) iodonium hexafluorophosphate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (penta Fluorophenyl) borate, 4,4'-bi (Diphenylsulfonio) diphenylsulfide bishexafluorophosphate, 4,4′-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenylsulfide bishexafluoroantimonate, 4,4′-bis [di (β- Hydroxyethoxy) phenylsulfonio] diphenylsulfide bishexafluorophosphate, 7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone hexafluoroantimonate, 7- [di (p-toluyl) sulfonio] -2-isopropyl Thioxanthone tetrakis (pentafluorophenyl) borate, 4-phenylcarbonyl-4'-diphenylsulfonio-diphenylsulfide hexafluorophosphate, 4- (p-tert-butylphenylcarbonyl)- Aromatics such as 4′-diphenylsulfonio-diphenylsulfide hexafluoroantimonate, 4- (p-tert-butylphenylcarbonyl) -4′-di (p-toluyl) sulfonio-diphenylsulfide tetrakis (pentafluorophenyl) borate Onium salts such as sulfonium salts, xylene-cyclopentadienyl iron (II) hexafluoroantimonate, cumene-cyclopentadienyl iron (II) hexafluorophosphate, xylene-cyclopentadienyl iron (II) tris (tri And iron-allene complexes such as (fluoromethylsulfonyl) methanide.
These may be used alone or in combination of two or more.

  Among the above photopolymerization initiators, radical polymerization initiators that are excellent in reactivity even when added in a small amount and can shorten the process time are preferably used.

The content of the photopolymerization initiator in the acrylic coating composition is based on 100 parts by weight of a specific acrylate (when other acrylate is included, the total acrylate is the sum of the specific acrylate and the other acrylate). 0.0001 parts by weight or more and 20 parts by weight or less, more preferably 0.001 parts by weight or more and 15 parts by weight or less, and a ratio of 0.01 parts by weight or more and 10 parts by weight or less. More preferably.
By including a photopolymerization initiator in the acrylic coating composition within such a range, the acrylic coating layer is sufficiently cured and high adhesion to the polycarbonate layer can be obtained.

  The acrylic coating composition may contain appropriate amounts of other various additives as additive components other than the photopolymerization initiator.

In addition, the acrylic coating composition can be used by adding a solvent, if necessary, in order to improve the applicability to the polycarbonate layer. That is, this acrylic coating composition can be used as a solution, and this solution can be applied to a polycarbonate layer and cured to form an acrylic coating layer.
The type and amount of the solvent can be appropriately selected according to various coating methods described later.

  Examples of the solvent include alcohols such as isopropyl alcohol, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, esters such as ethyl acetate and butyl acetate, aromatics such as toluene and xylene, and cyclohexanone. be able to. These may be used alone or in combination of two or more.

  Although the usage-amount of these solvents is not specifically limited, Usually, it uses so that the solid content density | concentration of an acrylic coating composition may be about 0.01-99.99 weight%.

  The film thickness of the acrylic coat layer is preferably 10 μm or less, more preferably 5 μm or less, from the viewpoint of reducing the thickness of the film of the present invention and the polarizing plate of the present invention using the film and preventing distortion (curing shrinkage) of the polycarbonate layer. 3 μm or less is more preferable. Moreover, from a viewpoint of adhesive strength, 0.1 micrometer or more is preferable, 0.2 micrometer or more is more preferable, and 0.3 micrometer or more is further more preferable. If it is the said range, favorable adhesiveness can be acquired with respect to both a polycarbonate layer and the below-mentioned aqueous adhesive.

Moreover, the ratio (t1 / t2) of the film thickness (t1) of the polycarbonate layer and the film thickness (t2) of the acrylic coat layer is preferably 1-1000, more preferably 3-500, and even more preferably. 5 to 200. If t1 / t2 is in the above range, it is preferable that the strength of the polycarbonate layer is not reduced, wrinkles are generated, and retardation is not increased even when the acrylic coating composition is cured.
In the present invention, the acrylic coat layer is formed on at least one side of the polycarbonate layer, and the acrylic coat layer may be formed on both sides of the polycarbonate layer. The film thickness of the acrylic coat layer is a value of the film thickness of the acrylic coat layer per one side of the polycarbonate layer. When the acrylic coating layer is formed on both surfaces of the polycarbonate layer, the thickness of the acrylic coating layer per one side is preferably not less than the above lower limit, and the total thickness of the acrylic coating layers on both surfaces is not more than the above upper limit. It is preferable that Moreover, it is preferable that the film thickness of the acrylic coating layer of both surfaces is equal from the surface of prevention of the curvature etc. of a film.

  The acrylic coat layer is formed by applying and curing an acrylic coating composition on at least one side of the polycarbonate layer of the present invention. When a solvent is added to the acrylic coating composition, the acrylic coating layer is formed by applying the acrylic coating composition, drying it, and then curing it.

  The acrylic coating layer may be provided by in-line coating, which treats the film surface during the process of forming a polycarbonate film, which is a polycarbonate layer, and is provided by off-line coating, which is applied to the film once manufactured outside the system. Also good. Since the coating can be performed simultaneously with the film formation, the production can be handled at a low cost, and therefore in-line coating is preferably used.

  In the present invention, the method for applying the acrylic coating composition to one side of the polycarbonate layer is not particularly limited, and a conventionally known coating such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, curtain coating, etc. A scheme can be used.

  Although it does not specifically limit regarding drying of the dilution solvent etc. at the time of forming an acrylic coat layer on a polycarbonate layer, Usually, it is 5-200 seconds at 60-200 degreeC, Preferably it is 10-100 at 70-180 degreeC. Drying should be performed using seconds as a guide.

  Regarding the curing conditions when forming the acrylic coating layer on the polycarbonate layer, it is preferable to perform active energy ray irradiation such as ultraviolet ray irradiation and electron beam irradiation. For example, when curing by ultraviolet irradiation, one or a plurality of light sources such as high-pressure mercury or metal halide lamps having an illuminance of 1 to 500 W / cm are used, and light having a wavelength of 200 to 450 nm is irradiated. The irradiation conditions are usually 50 mJ to 5000 mJ, preferably 100 mJ to 4000 mJ, more preferably 200 mJ to 3000 mJ, and still more preferably 300 mJ to 2000 mJ in terms of cumulative irradiation. By irradiating in the above range, the acrylic coating layer can be sufficiently cured without causing a large deterioration in the polycarbonate film.

Moreover, it is possible to use either an inline coat or an outline coat as a method of forming an acrylic coat layer on a polycarbonate layer. The line speed is usually 0.5 to 500 m / min, preferably 1 to 300 m / min, more preferably 5 to 200 m / min, and more preferably 10 to 100 m / min from the viewpoints of the drying and curing conditions. Is more preferable.
In the present invention, a method by heat treatment can also be used as a method for curing the coat layer. However, the above-described method using irradiation with active energy rays such as ultraviolet irradiation does not require aging when heat treatment is performed, and is preferable in terms of productivity.

3. Polarizing plate Although there is no restriction | limiting in particular in the use of the film of this invention, Since it is excellent in transparency, dimensional stability, and heat-and-moisture resistance, it can be used suitably especially as a protective film of the polarizing film of a polarizing plate.

When using the film of this invention as a protective film of the polarizing film in a polarizing plate, for example, generally, a polarizing film is bonded together through the adhesive agent for adhere | attaching a polarizing film on the acrylic coat layer side.
As the adhesive, conventionally known ones can be used, for example, water-based adhesives such as polyvinyl alcohol and urethane compounds, active energy ray-curable adhesives such as acrylic compounds, epoxy compounds, and oxazoline compounds. Can be mentioned. Among these, water-based adhesives such as polyvinyl alcohol are preferable from the viewpoints of adhesiveness with polyvinyl alcohol (PVA), which is a polarizing film, and environmental safety in wastes.

After forming an adhesive layer by applying an adhesive such as a water-based adhesive on the acrylic coat layer of the film of the present invention, a polarized light such as a polyvinyl alcohol film that is uniaxially stretched and dyed with iodine or the like is formed thereon. Bond the membranes together. A protective film, a retardation film, or the like can be bonded to the opposite side of the polarizing film to form a polarizing plate.
That is, the polarizing plate of the present invention using the film of the present invention has a layer structure of a first protective film / adhesive layer / polarizing film / adhesive layer / second protective film. Of these, it is used as at least one protective film.

4). Liquid crystal display device The film of the present invention is excellent in transparency, dimensional stability and heat and humidity resistance, and can be adhered with good adhesion to a polarizing film. Therefore, the polarized light of the present invention using such a film of the present invention. The plate is excellent in the protective effect and function maintenance of the polarizing film, and can realize a high-quality display screen as a polarizing plate of a liquid crystal display device such as a television, a personal computer, a digital camera, or a mobile phone.

  As described above, the liquid crystal display has the configuration of the front side polarizing plate / liquid crystal / rear side polarizing plate, and the polarizing plate has the configuration of protective film / polarizing film / protective film, and thus constitutes the front side polarizing plate. The protective films disposed on the front side and the rear side of the polarizing film are the protective film A and the protective film B, respectively, and the protective films disposed on the front side and the rear side of the polarizing film constituting the rear polarizing plate are the protective film C, If it is set as the protective film D, the whole structure will be protective film A / front side polarizing film / protective film B / liquid crystal / protective film C / rear side polarizing film / protective film D from the front side.

  When the film of the present invention is a double-sided adhesive type having an acrylic coat layer on both sides of the polycarbonate layer of the present invention, a polarizing film is adhered to one acrylic coat layer side through the adhesive layer, and the other acrylic Another functional film or a transparent substrate can be bonded to the coat layer side via the above-mentioned adhesive layer. Other functional film is not particularly limited, for example, high refractive index film, low refractive index film, antireflection film laminated with these, optical correction film such as color correction film, hard coat film, antifouling film, Examples thereof include an electromagnetic wave shielding film, an infrared ray absorbing film, and an ultraviolet ray absorbing film. Moreover, as a transparent base material, the glass as a support substrate and various transparent films are mentioned.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by these examples and comparative examples.

[Evaluation method]
In the following, measurement and evaluation of various physical properties and the like were performed as follows.
<Polycarbonate adhesion between (P C) Film>
The prepared coating films were bonded to each other with an aqueous adhesive (Nippon Gosei Co., Ltd. Gohsenx Z-200) with the coating layer as the adhesive surface side, and heated at 100 ° C. for 30 minutes to prepare a sample for evaluation. . After this sample was cut at a width of 25 mm, T-type peeling was performed at a test speed of 50 mm / min using a universal tensile tester (manufactured by Intesco, model: 200X). The result of the peel test was determined according to the following criteria.
○: The film does not peel and the material breaks down.
(Triangle | delta): Peeling strength is 1 N / 25mm width or more.
X: Peel strength is less than 1 N / 25 mm width.

<Adhesiveness with PVA film>
The prepared coating film and biaxially stretched PVA film (manufactured by Nihon Gosei Co., Ltd., trade name: Bobron, thickness: 40 μm) are coated with the coating layer of the coating film as the adhesive side, and an aqueous adhesive (Nihon Gosei Co., Ltd.) The sample for evaluation was produced by bonding together with Gohsenx Z-200) and heating at 100 ° C. for 30 minutes. After this sample was cut at a width of 25 mm, T-type peeling was performed at a test speed of 50 mm / min using a universal tensile tester (manufactured by Intesco, model: 200X). The result of the peel test was determined according to the following criteria.
○: The film does not peel and the material breaks down.
X: Peel without breaking the material.

<Moisture resistance>
The evaluation sample produced in the above “adhesiveness with PVA film” was left in a constant temperature and humidity chamber for 120 hours under the conditions of 85 ° C. and 85% RH, and then the same peel test was performed. The result of the peel test was determined according to the following criteria.
○: The film does not peel and the material breaks down.
X: Peel without breaking the material.

<Appearance and deformation of film>
The appearance of the produced coating film was visually observed and judged according to the following criteria.
○: The film is almost free of waviness and edge lifting, and is in a good state.
(Triangle | delta): A film has a wave and / or a float of an edge part.
X: Winding (curl) occurs at the end of the film.

[Polycarbonate film]
The polycarbonate film used for the production of the coating film was produced as follows.
The molar ratio of the structural unit derived from isosorbide which is a dihydroxy compound and the structural unit derived from tricyclodecane dimethanol is isosorbide / tricyclodecane dimethanol = 6/4 by a method according to JP2008-024919A. A polycarbonate copolymer having a glass transition temperature of 126 ° C. was obtained.
The polycarbonate copolymer is put into a φ65 mm single screw extruder, melt-kneaded at a barrel set temperature of 220 to 240 ° C., and extruded from a die having a width of 1350 mm and a lip gap of 0.7 mm (set temperature 240 ° C.). A polycarbonate film having a thickness of 100 μm was produced by winding with a cast roll whose temperature was adjusted to 65 ° C. The polycarbonate film was subjected to corona treatment with a cumulative irradiation amount of 1000 W / m ² using a corona treatment device, and then cut into 100 mm × 200 mm with the MD direction as the longitudinal direction.

[Example 1]
2-hydroxy-3-methacrylpropyl acrylate (701A, manufactured by Shin-Nakamura Chemical Co., Ltd., molecular weight: 214, acrylate functional number: 2), 100 parts by weight of α-hydroxyalkylphenone based on hydroxyl group-containing acrylate An acrylic coating composition was prepared by blending 5 parts by weight of an agent (manufactured by BASF, IRGACURE 184) and mixing 100 parts by weight of isopropyl alcohol as a diluent solvent. This acrylic coating composition was coated on the polycarbonate film using a bar coater # 8 and then dried at 100 ° C. for 1 minute, and then UV irradiation apparatus (UIT250, manufactured by USHIO, high pressure mercury lamp 160 W / cm, height 150 mm) The coating film of the present invention was prepared by curing by UV irradiation at an integrated irradiation amount of 1000 mJ at a line speed of 2 m / min. To form an acrylic coating layer on a polycarbonate film. As a result of measuring the film thickness of the acrylic coat layer of this coating film, the film thickness was 3 μm.
The film thickness of the acrylic coat layer was measured with an optical microscope after the cross section of the coating film was cut out with a microtome. The same applies to the following examples and comparative examples.

[Example 2]
The same as in Example 1, except that the hydroxyl group-containing acrylate was changed to 100 parts by weight of 2-hydroxyethyl acrylate (2-HEA, manufactured by Shin-Nakamura Chemical Co., Ltd., molecular weight: 116, acrylate functionality: 1). A coating film was prepared by the method described above. As a result of measuring the film thickness of the acrylic coat layer of this coating film, the film thickness was 3 μm.

[Example 3]
In Example 1, 70 parts by weight of 2-hydroxy-3-methacrylpropyl acrylate and dipentaerythritol hexaacrylate (A-DPH, manufactured by Shin-Nakamura Chemical Co., Ltd., molecular weight: 578, acrylate functionality: 6) A coating film was prepared in the same manner except that the content was changed to 30 parts by weight. As a result of measuring the film thickness of the acrylic coat layer of this coating film, the film thickness was 3 μm.

[Example 4]
A coating film was prepared in the same manner as in Example 1 except that the acrylate was changed to a blend of 50 parts by weight of 2-hydroxy-3-methacrylpropyl acrylate and 50 parts by weight of dipentaerythritol hexaacrylate. . As a result of measuring the film thickness of the acrylic coat layer of this coating film, the film thickness was 3 μm.

[Example 5]
A coating film was prepared in the same manner as in Example 1 except that the acrylate was changed to a blend of 30 parts by weight of 2-hydroxy-3-methacrylpropyl acrylate and 70 parts by weight of dipentaerythritol hexaacrylate. . As a result of measuring the film thickness of the acrylic coating layer of this coating film, the film thickness was 4 μm.

[Comparative Example 1]
The uncoated film of the polycarbonate film was used as the film of Comparative Example 1.

[Comparative Example 2]
In the same manner as in Example 1, except that the acrylate was changed to 100 parts by weight of tricyclodecane dimethanol acrylate (A-CDP, manufactured by Shin-Nakamura Chemical Co., Ltd., molecular weight: 332, acrylate functionality: 2). A coating film was prepared. As a result of measuring the film thickness of the acrylic coating layer of this coating film, the film thickness was 4 μm.

[Comparative Example 3]
In Example 1, except that the acrylate was changed to 100 parts by weight of ethoxylated glycerin acrylate (A-GLY-3E, manufactured by Shin-Nakamura Chemical Co., Ltd., average weight molecular weight (Mw): 386, acrylate functionality: 3). Prepared a coating film by the same method. As a result of measuring the film thickness of the acrylic coating layer of this coating film, the film thickness was 4 μm.

[Comparative Example 4]
Coating was carried out in the same manner as in Example 1 except that acrylate was changed to 100 parts by weight of dipentaerythritol hexaacrylate (A-DPH, Shin-Nakamura Chemical Co., Ltd., molecular weight: 578, acrylate functionality: 6). A film was prepared. As a result of measuring the film thickness of the acrylic coating layer of this coating film, the film thickness was 4 μm.

[Comparative Example 5]
100 parts by weight of urethane resin (Hydran WLS-212, manufactured by DIC Corporation) as an aqueous coating agent, 2 parts by weight of an epoxy-based crosslinking agent (CR-5L, manufactured by DIC Corporation) and 270 parts by weight of ion-exchanged water By mixing, a coating resin composition was prepared. The coating resin composition was coated on the polycarbonate film using a bar coater # 8, and then dried and solidified at 100 ° C. for 30 minutes to prepare a coating film. As a result of measuring the film thickness of the coating layer of this coating film, the film thickness was 3 μm.

Table 1 shows the physical properties and blending ratios of the acrylates used for forming the acrylic coating layer in Examples 1 to 5 and Comparative Examples 2 to 4.
Table 2 shows the evaluation results of the films in Examples 1 to 5 and Comparative Examples 1 to 5.

  As is clear from Tables 1 and 2, the polycarbonate films coated with the acrylic coating compositions described in Examples 1 to 5 of the present invention are all excellent in adhesiveness and moisture resistance with aqueous adhesives. showed that. On the other hand, the films of Comparative Examples 1 to 3 and 5 resulted in inferior adhesiveness with a polycarbonate film or an aqueous adhesive. The film of Comparative Example 4 showed good adhesion, but the appearance was impaired.

Claims (9)

The Po polycarbonate resin on at least one surface of the polycarbonate layer mainly has a coating layer of one or more do not contain acrylate containing a cyclic imine compounds having a hydroxyl group composition, water-based adhesive in the coating layer A laminate comprising an agent layer . The laminate according to claim 1, wherein the polycarbonate resin is a polycarbonate resin containing a structural unit derived from a dihydroxy compound represented by the following formula (1).

The laminate according to claim 1 or 2 , wherein the acrylate is a monofunctional acrylate and / or a bifunctional acrylate. The laminate according to any one of claims 1 to 3, wherein the polycarbonate resin further contains a structural unit derived from tricyclodecane dimethanol represented by the following formula (2).

Laminate according to any one of claims 1 to 4, characterized in that the composition contains a photopolymerization initiator. The laminate according to any one of claims 1 to 5 , wherein the relationship between the film thickness (t1) of the polycarbonate layer and the film thickness (t2) of the coat layer is 1≤t1 / t2≤1000. The layered product according to any one of claims 1 to 6 , wherein the coat layer has a thickness of 0.1 to 10 µm. Polarizing plate obtained by bonding a polarizing film on the coating layer of the laminate via the aqueous adhesive layer according to any one of claims 1-7. A liquid crystal display device comprising the polarizing plate according to claim 8 .