JP2018124299A - Polarizing plate with adhesive layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarizing plate with adhesive layer which suppresses deformation of an acrylic protective layer itself, and prevents floating and peeling on an adhesive interface between the acrylic protective layer and the adhesive layer, under high temperature and high humidity environment.SOLUTION: A polarizing plate 10 with adhesive layer has a protective layer 40 formed of a polarizer containing a polyvinyl alcohol resin and a (meth)acrylic resin composition, and an adhesive layer 50, where the adhesive layer contains an acrylic polymer (A) which is obtained by copolymerization of a monomer mixture of 0 pts.mass or more and 6 pts.mass or less of a monomer (a) having a crosslinkable functional group and 0-99.5 pts.mass of an alkyl(meth)acrylic monomer (b) having an alkyl chain having 8 or more carbon atoms, and has a weight average molecular weight of 600,000 to 3,000,000, an acid value of the acrylic polymer (A) is 1-50 mgKOH/g, and storage elastic modulus (G') at 23°C and measurement frequency of 1 Hz of the adhesive layer is 1.0×10to 3.0×10Pa.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polarizing plate with an adhesive layer.

  In recent years, with the trend toward lighter and thinner displays, thinning of polarizing plates has been actively studied. However, as a result of thinning, a conventional triacetylcellulose layer (TAC layer) as a conventional polarizer protective layer is also thinned, and thus a polyvinyl alcohol (PVA) resin that was originally an essential function as a polarizer protective layer There is a tendency that the physical and chemical protective ability of the polarizer made is insufficient.

  Therefore, as described in, for example, Patent Document 1, an alternative to an acrylic protective layer that has a higher protection function than TAC and is highly transparent has been studied. Low, and the water absorption rate tends to be somewhat high. If an adhesive layer is formed on the acrylic protective layer and other optical members are attached, the acrylic protective layer can be used in high temperature and high humidity environments. Deformation of itself, floating at the adhesive interface, peeling off, etc. are likely to occur, and this may cause problems in display performance as a display including a polarizing plate.

JP 2010-277039 A

  In the present invention, the acrylic protective layer of the polarizer made of polyvinyl alcohol resin is attached to the acrylic protective layer of a specific pressure-sensitive adhesive, so that the acrylic protective layer itself can be used even in a high temperature and high humidity environment. An object of the present invention is to provide a highly reliable polarizing plate with a pressure-sensitive adhesive layer that suppresses deformation and floats at the adhesive interface between the acrylic protective layer and the pressure-sensitive adhesive layer and does not cause peeling.

  In order to solve the above problems, the present inventors have more than 0 to 6 parts by mass of a monomer having a crosslinkable functional group and 0 to 99 of an alkyl (meth) acrylic monomer having an alkyl chain having 8 or more carbon atoms. A pressure-sensitive adhesive layer containing a (meth) acrylic polymer having a weight average molecular weight of 600,000 to 3,000,000, and having a specific acid value and storage elastic modulus, which is obtained by copolymerizing a monomer mixture containing 5 parts by mass By using it, it develops strong adhesion and elasticity, suppresses deformation of the acrylic protective layer itself even under harsh environments of high temperature and high humidity, and floats at the adhesive interface between the acrylic protective layer and the adhesive layer The present inventors have found that a highly reliable polarizing plate with an adhesive layer that does not cause peeling can be obtained.

That is, a polarizing plate with an adhesive layer according to one embodiment of the present invention includes a layered polarizer containing a polyvinyl alcohol resin, an adhesive layer, a protective layer made of a (meth) acrylic resin composition, and an adhesive layer. And at least one surface of the layered polarizer is in contact with one surface of the adhesive layer, and the other surface of the adhesive layer is in contact with one surface of the protective layer. One surface of the pressure-sensitive adhesive layer is in contact with the other surface of the protective layer, and the pressure-sensitive adhesive layer comprises more than 0 parts by mass and less than 6 parts by mass of the monomer (a) having a crosslinkable functional group, and carbon of an alkyl chain. Acrylic polymer (A) having a weight average molecular weight of 600,000 to 3,000,000, which is obtained by copolymerizing a monomer mixture containing 0 to 99.5 parts by mass of alkyl (meth) acrylic monomer (b) having a number of 8 or more The acid value of the acrylic polymer (A) is 1 to 5 a mg KOH / g, 23 ℃ of the adhesive layer, and wherein the storage modulus at a measuring frequency of 1 Hz (G') is ^{1.0 × 10 4 ~3.0 × 10 5} Pa.

  In the polarizing plate with the pressure-sensitive adhesive layer according to one embodiment of the present invention, the monomer (a) having a crosslinkable functional group has a (meth) acrylic monomer having a hydroxyl group and / or a carboxyl group (meth). It is an acrylic monomer.

  Moreover, the polarizing plate with an adhesive layer by one Embodiment of this invention is characterized by the said adhesive layer containing a crosslinking agent (B).

  Moreover, the polarizing plate with an adhesive layer by one Embodiment of this invention is characterized by the said adhesive layer containing a silane coupling agent (C).

Moreover, as for the polarizing plate with an adhesive layer by one embodiment of this invention, the said adhesive layer has a storage elastic modulus (G ') in the measurement frequency of 1 Hz at 80 degreeC, and 7.5 * 10 < ³ > -1.5. It is characterized by being × 10 ⁵ Pa.

  Moreover, the polarizing plate with an adhesive layer by one Embodiment of this invention is characterized by the said adhesive layer having a gel fraction of 60-90 mass%.

  According to the present invention, even under a high temperature and high humidity environment, the deformation of the acrylic protective layer itself is suppressed, and the acrylic protective layer and the pressure-sensitive adhesive layer float on the adhesive interface without causing peeling. A highly reliable polarizing plate with an adhesive layer can be obtained.

FIG. 1 is a schematic view showing a polarizing plate with an adhesive according to an embodiment of the present invention.

  Hereinafter, the present invention will be described in detail. In the present invention, “part” means “mass%” and “%” means “mass%” unless otherwise specified. Further, in the present invention, ““ numerical value 1 ”to“ numerical value 2 ”” means a numerical range including “numerical value 1” and “numerical value 2” at the end points, and “more than“ numerical value 3 ”means It means a numerical range that does not include “Numeric Value 3” at the end point and is larger than “Numeric Value 3”. Further, unless otherwise specified in the present invention, “adhesive” refers to a concept including “pressure-sensitive adhesive”.

<Polarizing plate with adhesive layer>
A polarizing plate with an adhesive layer according to an embodiment of the present invention includes a layered polarizer containing a polyvinyl alcohol resin, an adhesive layer, a protective layer made of a (meth) acrylic resin composition, and an adhesive layer. A polarizing plate with a pressure-sensitive adhesive layer, wherein at least one surface of the layered polarizer is in contact with one surface of the adhesive layer, and the other surface of the adhesive layer is in contact with one surface of the protective layer, One surface of the pressure-sensitive adhesive layer is in contact with the other surface of the protective layer.

  That is, the polarizing plate with the pressure-sensitive adhesive layer is obtained by sticking a layered polarizer and a protective layer made of a (meth) acrylic resin composition with an adhesive layer, and further, on the other surface of the protective layer, a pressure-sensitive adhesive layer. The one side of is attached.

  The surface of the pressure-sensitive adhesive layer that is not in contact with the protective layer may be in contact with a sheet-like material, for example, a release film (hereinafter also referred to as a separator), or in contact with another optical member. The pressure-sensitive adhesive layer surface may be exposed without contacting any member.

  Note that one surface of another adhesive layer may be brought into contact with the other surface of the above-described layered polarizer, and an arbitrary protective layer may be brought into contact with the other surface of the adhesive layer. In this case, the “arbitrary protective layer” may be composed of a (meth) acrylic resin composition as in the protective layer of the present invention, or TAC, cycloolefin (COP), polyethylene terephthalate (PET), etc. The resin composition may be used.

<Layered polarizer>
The layered polarizer of the present invention contains a polyvinyl alcohol resin (PVA resin) and is a vinyl alcohol resin film such as a conventionally known PVA film, partially formalized PVA film, or ethylene-vinyl alcohol resin film. And uniaxially stretched by adsorbing a dichroic material such as iodine or a dichroic dye (see, for example, JP-A Nos. 2001-296427 and 7-333426), (ii) above (i ) Having a birefringent material having liquid crystallinity together with a dichroic material in a vinyl alcohol resin film (see, for example, JP-A-2007-72203), (iii) PVA resin or ethylene-vinyl alcohol system Polyethylene obtained by dehydrating or deaceticating the resin to introduce a continuous polyene structure and stretching it. System film (e.g., see JP Patent 2007-17845.), And the like.

  Among these, a layered polarizer composed of a uniaxially stretched film in which iodine is adsorbed on a PVA-based film is preferable because of excellent polarization characteristics.

  The thickness of such a polarizer is usually 0.1 to 100 μm, particularly 1 to 30 μm, and more preferably 3 to 15 μm.

<Protective layer>
The protective layer of the present invention comprises a (meth) acrylic resin composition, and is adhered to at least one surface of the layered polarizer using an adhesive layer. That is, the protective layer is made of a (meth) acrylic resin composition, and has a low water permeability and high transparency compared to a conventional triacetyl cellulose (TAC) protective layer. To do.

  The material for the protective layer is not particularly limited as long as it is mainly composed of (meth) acrylic resin, and conventionally known cyclic olefin-based resins, polyethylene terephthalate and polyethylene naphthalate can be used as the (meth) acrylic resin. Polyester resins such as polystyrene, polystyrene resins such as polystyrene and acrylonitrile / styrene copolymers, polyolefin resins such as polyethylene and polypropylene, polyarylate resins, polycarbonate resins, vinyl chloride resins, nylon and aromatic polyamides, etc. Amide resins, (fluorinated) polyimide resins, polyetheretherketone resins, polyphenylene sulfide resins, vinylidene chloride resins, polyvinyl acetal resins such as polyvinyl butyral, polyoxymethylene resins, epoxy Etc. may be made by blending a resin.

  In addition, the term “having (meth) acrylic resin as a main component” here means that when the total mass of the protective layer is 100 parts by mass, the proportion of the (meth) acrylic resin is 70% by mass or more. Say.

  As the (meth) acrylic resin of the present invention, poly (meth) acrylic acid ester such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid ester copolymer Polymer, methyl methacrylate-acrylic ester- (meth) acrylic acid copolymer, methyl (meth) acrylate-styrene copolymer, polymer having alicyclic hydrocarbon group [for example, methyl methacrylate-methacrylic acid Cyclohexyl copolymer, methyl methacrylate- (meth) acrylate norbornyl copolymer, etc.), (meth) acrylic resin with a high glass transition temperature obtained by intramolecular crosslinking or intramolecular cyclization reaction, rubber-acrylic graft Type core-shell polymer.

  Examples of such commercially available (meth) acrylic resin films include “Acrypet VRL20A”, “Acrypet IRD-70” manufactured by Mitsubishi Rayon Co., Ltd., “MUX-60” manufactured by UMGABS, and the like.

  Various surface treatments can be performed to increase the affinity between the protective layer and the adhesive layer, and (meth) acrylic ester latex, styrene latex, polyethyleneimine, and polyurethane are formed on the surface of the protective layer. / Easy adhesion layer or anchor coat layer containing polyester copolymer, etc., or surface treatment or corona treatment with a coupling agent such as silane coupling agent or titanium coupling agent may be performed. It is also possible to use methods together.

  In addition, an antistatic agent coated on the surface of the protective layer or contained in a film is also preferably used.

  The thickness of such a protective layer is not particularly limited, but is usually thicker than the polarizer, and has a function of imparting strength as a base material of the polarizer, and is usually 5 to 100 μm, preferably 10 to 80 μm. is there.

  In addition, such a protective film can be provided with a hard coat layer on the surface where the polarizer is not laminated, or can be subjected to various treatments such as anti-sticking, anti-reflection and anti-glare.

<Adhesive layer>
The adhesive layer of the present invention is in contact with the layered polarizer and the protective layer. That is, the adhesive layer is formed by sticking a layered polarizer and a protective layer.

  The adhesive which comprises the said adhesive bond layer is not specifically limited, Conventionally well-known things, such as an acrylic adhesive and an epoxy-type adhesive agent, can be used.

<Adhesive layer>
The pressure-sensitive adhesive layer of the present invention is formed by contacting the surface of the two surfaces of the protective layer that is not in contact with the adhesive layer. That is, at least one surface of the pressure-sensitive adhesive layer is in contact with the protective layer.

The said adhesive layer consists of an adhesive containing an acrylic polymer (A), and the storage elastic modulus (G ') in 23 degreeC and the measurement frequency of 1 Hz is 1.0 * 10 < ⁴ > -3.0 * 10 < ⁵ >. It is characterized by being Pa.

  The pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer may optionally contain a crosslinking agent (B), a silane coupling agent (C), an antistatic agent (D), other additives (E), and the like. Good.

  Here, each structural component of the adhesive composition which comprises the said adhesive layer is explained in full detail.

Acrylic polymer (A)
The acrylic polymer (A) of the present invention is an alkyl (meth) acrylic monomer having at least 0 part by mass and not more than 6 parts by mass of the monomer (a) having a crosslinkable functional group and an alkyl chain having 8 or more carbon atoms. It is a thing of the weight average molecular weight 600,000-3 million formed by copolymerizing the monomer mixture containing 0-99.5 mass parts of (b).

  That is, the acrylic polymer (A) contains the monomer (a) as an essential comonomer component, but the monomer (b) is an optional component, and optionally further includes a monomer (c ) May be included.

Monomer (a) having a crosslinkable functional group
The term “crosslinkable functional group” as used herein refers to a reaction between the functional group and a functional group in another polymer chain when it is incorporated into a polymer chain as a polymerization component and then constitutes an adhesive layer, or It refers to a functional group that can form a three-dimensional cross-link between polymer chains in the system of the pressure-sensitive adhesive layer by a reaction between the functional group and the cross-linking agent (B).

  Examples of such a crosslinkable functional group include a hydroxyl group, an amino group, and a carboxyl group.

  Examples of the monomer having a hydroxyl group as a crosslinkable functional group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxy-3-chloropropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, ethylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene A glycol (meth) acrylate etc. are mentioned, Among these, 1 type can be used individually or in combination of 2 or more types.

  Examples of the monomer having an amino group as a crosslinkable functional group include N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, N, N′-dimethylaminoethyl (meth) acrylamide, N, N′-dimethylaminopropyl (meth) acrylamide, acrylamide and the like can be mentioned, and one of these may be used alone or in combination of two or more. it can.

  Examples of the monomer having a carboxyl group as the crosslinkable functional group include (meth) acrylic acid, maleic acid crotonic acid, itaconic acid, citraconic acid, maleic anhydride, itaconic anhydride, and the like. Or two or more types can be used in combination.

  Among the monomers having a crosslinkable functional group, a monomer having a hydroxyl group is preferred from the viewpoint of easily forming a three-dimensional crosslinked structure in the system of the pressure-sensitive adhesive layer, more specifically, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and 6-hydroxyhexyl (meth) acrylate are preferred.

  The blending amount of the monomer (a) having a crosslinkable functional group is more than 0 parts by mass and less than 6 parts by mass, preferably 0.05 to 6 parts by mass, more preferably 100 parts by mass of the total mass of the acrylic polymer (A). Is 0.1 to 5 parts by mass.

  When the blending amount of the monomer (a) having a crosslinkable functional group is more than 0 parts by mass, the resulting polymer and the pressure-sensitive adhesive layer are imparted with an appropriate cohesive force, and are excellent in heat resistance and moisture and heat resistance. A polarizing plate with a layer can be obtained, and by controlling the blending amount to 6 parts by mass or less, the polarity of the pressure-sensitive adhesive layer is suppressed to be low, thereby maintaining the hydrophobicity, thereby reducing the water vapor transmission rate and improving the water vapor barrier property. be able to.

    Alkyl (meth) acrylic monomer (b)

  The alkyl (meth) acrylic monomer (b) of the present invention is an acrylic monomer having a linear, branched or cyclic alkyl group having 8 or more carbon atoms.

  Examples of such monomers include 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, n-lauryl (meth) acrylate, n-tetradecyl (meth) acrylate, and n-hexadecyl. (Meth) acrylate, stearyl (meth) acrylate, isooctyl (meth) acrylate, isostearyl (meth) acrylate, dicyclopentanyl (meth) acrylate, isobornyl (meth) acrylate, and the like. Or two or more types can be used in combination.

  Although there is no restriction | limiting in particular in carbon number of the alkyl group in an alkyl (meth) acrylic-type monomer (b), Usually, it is 18 or less.

  The acrylic polymer (A) of the present invention does not have the alkyl (meth) acrylic monomer (b) as an essential polymerization component, but imparts hydrophobicity to the pressure-sensitive adhesive layer to lower the water vapor permeability, thereby improving the water vapor barrier property. It is preferable to add the alkyl (meth) acrylic monomer (b) to the acrylic polymer (A) of the present invention, and lauryl (meth) acrylate and isostearyl (meth) acrylate are particularly preferable. .

  The compounding amount of the alkyl (meth) acrylic monomer (b) is 0 to 98 parts by mass, preferably 15 to 97 parts by mass, more preferably 18 to 96 parts by mass, in 100 parts by mass of the total mass of the acrylic polymer (A). It is.

Monomer (c)
The acrylic polymer (A) of the present invention may optionally contain other monomers (c) in addition to the monomers (a) and (b) described above. The monomer (c) is, for example, an alkyl (meth) acrylic monomer or aromatic ring-containing monomer having a linear, branched or cyclic alkyl group having 1 to 7 carbon atoms, specifically, methyl (meth). Acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, benzyl (meth) acrylate, styrene, etc. Of these, one can be used alone, or two or more can be used in combination.

  When the monomer (c) is blended, butyl (meth) acrylate and benzyl (meth) acrylate are preferred because the physical properties of the adhesive when the pressure-sensitive adhesive layer is formed can be easily controlled.

  The compounding quantity of another monomer (c) is 0-98 mass parts in 100 mass parts of total mass of an acryl-type polymer (A).

Weight average molecular weight of acrylic polymer (A) The acrylic polymer (A) has a weight average molecular weight (Mw) of 600,000 to 3,000,000, preferably 700,000 to 2,500,000, more preferably 800,000 to 200. Ten thousand. A weight average molecular weight of 600,000 to 3,000,000 is preferable from the viewpoint of enhancing the durability of the resulting pressure-sensitive adhesive layer and pressure-sensitive adhesive polarizing plate.

Acid value of acrylic polymer (A) The acrylic polymer (A) of the present invention has an acid value of 1 to 50 mgKOH / g, preferably 3 to 48 mgKOH / g, more preferably 8 to 35 mgKOH / g. g. The acid value of the acrylic polymer (A) is calculated by the following formula based on the molecular weight (X) of the carboxyl group-containing monomer used in the copolymerization and the blending amount (Y mass%) of the carboxyl group-containing monomer. The In the following formula, “56.1” is the molecular weight of KOH.

Acid value of acrylic polymer (mgKOH / g)
= 56.1 / X × Y / 100 × 1000
= 561 / X × Y

  When the acid value of the acrylic polymer (A) is in the range of 1 to 50 mgKOH / g, the resulting polarizing plate with the pressure-sensitive adhesive layer is excellent in heat resistance and moisture and heat resistance.

Preparation Method of Acrylic Polymer (A) The polymerization method of the acrylic polymer (A) of the present invention is not particularly limited and can be polymerized by a known method such as solution polymerization, emulsion polymerization, suspension polymerization, etc. In producing the pressure-sensitive adhesive composition of the present invention using the copolymer mixture obtained by the above, it is preferable to perform polymerization by solution polymerization from the viewpoint that the treatment process is relatively simple and can be performed in a short time.

  In solution polymerization, a predetermined organic solvent, each monomer, a polymerization initiator, and a chain transfer agent used as necessary are generally charged in a polymerization tank, and heated for several hours with stirring in a nitrogen stream. Is done.

  As the polymerization initiator, it is possible to use organic peroxides, azo compounds and the like that can be used in ordinary solution polymerization. Examples of such organic peroxides include t-butyl hydroperoxide, cumene hydroxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, caproyl peroxide, and di-i-propyl peroxydicarbonate. , Di-2-ethylhexyl peroxydicarbonate, t-butyl peroxybivalate, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, 2,2-bis (4,4- Di-t-amylperoxycyclohexyl) propane, 2,2-bis (4,4-di-t-octylperoxycyclohexyl) propane, 2,2-bis (4,4-di-α-cumylperoxycyclohexyl) ) Propane, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) ) Butane, 2,2-bis (4,4-di-t-octylperoxycyclohexyl) butane and the like. Examples of the azo compound include 2,2′-azobis-i-butyronitrile and 2,2 ′. -Azobis-2,4-dimethylvaleronitrile, 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, etc. can be mentioned.

  In preparing the acrylic polymer (A) of the present invention, a chain transfer agent may be used as necessary within the range not impairing the object and effect of the present invention.

Cross-linking agent (B)
The pressure-sensitive adhesive composition of the present invention may optionally contain a crosslinking agent (B). Such a crosslinking agent is not particularly limited as long as it is a crosslinking agent that can react with the acrylic polymer (A) at room temperature or under heating to form a crosslinked structure. For example, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, A metal chelate type crosslinking agent, an aziridine type crosslinking agent, etc. are mentioned, Especially an isocyanate type crosslinking agent and an epoxy type crosslinking agent are preferable. When using a crosslinking agent in this invention, among 1 type mentioned above, it can be used individually or in combination of 2 or more types.

  Examples of the isocyanate-based crosslinking agent include isocyanate monomers such as xylylene diisocyanate, tolylene diisocyanate, chlorophenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, and the like. Examples thereof include polyfunctional isocyanate compounds having two or more isocyanate groups in the molecule, isocyanurates, and derivatives thereof, which have been subjected to addition reaction with dihydric or higher alcohols such as methylolpropane.

  Examples of the epoxy crosslinking agent include 1,3-bis (N, N′-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, ethylene glycol diglycidyl. Examples include ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidylaniline, diglycidylamine and the like.

  The compounding quantity of a crosslinking agent (B) is 0-3 mass parts with respect to 100 mass parts of an acryl-type polymer (A), Preferably it is 0.005-2.5 mass parts, More preferably, it is 0.01-2 mass parts. It is. When the blending amount is in the range of 0.005 to 2.5 parts by mass, it is preferable in that the gel fraction and the storage elastic modulus of the pressure-sensitive adhesive layer can be adjusted to a predetermined range.

Silane coupling agent (C)
The pressure-sensitive adhesive composition of the present invention may optionally contain a silane coupling agent (C). Such silane coupling agents include, for example, polymerizable unsaturated group-containing silicon compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, and methacryloxypropyltrimethoxysilane; 3-glycidoxypropyltrimethoxysilane, 3- Silicon compounds having an epoxy structure such as glycidoxypropylmethyldimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane; 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-amino Amino group-containing silicon compounds such as propyltrimethoxysilane and N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane; 3-chloropropyltrimethoxysilane, 3-oxobutanoic acid 3- (trimethoxysilyl) propyl, And oligo -Type silane coupling agent, etc. Among them, it interacts with the functional group which reacts with the functional group contained in the acrylic polymer (A) to form a covalent bond, or interacts with the acrylic polymer (A). A silane coupling agent having a functional group capable of forming a bond due to this is preferable in that it does not easily cause peeling in a wet heat environment.

  The compounding quantity of a silane coupling agent (C) is 0-1 mass part with respect to 100 mass parts of an acryl-type polymer (A), Preferably it is 0.01-0.5 mass part, More preferably, it is 0.03-0. 3 parts by mass. When the blending amount is in the range of 0.01 to 0.5 parts by mass, when the pressure-sensitive adhesive layer is formed on the surface of the adherend using the pressure-sensitive adhesive composition, good adhesion to the adherend is maintained. Is preferable.

Antistatic agent (D)
The pressure-sensitive adhesive composition of the present invention may optionally contain an antistatic agent (D). As such an antistatic agent, for example, a liquid or solid ionic compound composed of an anion and a cation at 25 ° C. can be mentioned.

  More specifically, 2-methyl-1-pyrroline tetrafluoroborate, 1-ethyl-2-phenylindole tetrafluoroborate, 1,2-dimethylindole tetrafluoroborate, 1-ethylcarbazole tetrafluoroborate, 1-ethyl -3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium trifluoroacetate, 1-ethyl-3-methylimidazolium heptafluorobutyrate, 1- Ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium perfluorobutanesulfonate, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazole Mubis (trifluoromethanesulfonyl) imide, 1-ethyl-3-methylimidazolium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-3-methylimidazolium tris (trifluoromethanesulfonyl) methide, 1-butyl-3-methyl Imidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium trifluoroacetate, 1-butyl-3-methylimidazolium heptafluorobutyrate, 1-butyl- 3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium perfluorobutanesulfonate, 1-butyl-3-methylimidazolium bis (trifluoromethanesulfonyl) 1-hexyl-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium tetrafluoroborate, 1-hexyl-3-methylimidazolium Hexafluorophosphate, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, 1-octyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-2 , 3-Dimethylimidazolium tetrafluoroborate, 1,2-dimethyl-3-propylimidazolium bis (trifluoromethanesulfonyl) imide, 1-methylpyrazolium tetrafluoroborate, 3-methylpyrazolium tetrafluoro Roborate, tetrahexylammonium bis (trifluoromethanesulfonyl) imide, diallyldimethylammonium tetrafluoroborate, diallyldimethylammonium trifluoromethanesulfonate, diallyldimethylammonium bis (trifluoromethanesulfonyl) imide, diallyldimethylammonium bis (pentafluoroethanesulfonyl) imide, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium tetrafluoroborate, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium trifluoromethanesulfonate, N, N- Diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N- Tyl-N- (2-methoxyethyl) ammonium bis (pentafluoroethanesulfonyl) imide, glycidyltrimethylammonium trifluoromethanesulfonate, glycidyltrimethylammonium bis (trifluoromethanesulfonyl) imide, 1-octyl-4-methylpyridinium bis (fluorosulfonyl) ) Imide, tributylmethylammonium trifluoromethanesulfonylimide, glycidyltrimethylammonium bis (pentafluoroethanesulfonyl) imide, 1-butylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-butyl-3-methylpyridinium (trifluoromethanesulfonyl) tri Fluoroacetamide, 1-hexyl-4-methylpyridinium hexafluoro Sulfate, 1-ethyl-3-methylimidazolium (trifluoromethanesulfonyl) trifluoroacetamide, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium (trifluoromethanesulfonyl) trifluoroacetamide, diallyldimethyl Ammonium (trifluoromethanesulfonyl) trifluoroacetamide, glycidyltrimethylammonium (trifluoromethanesulfonyl) trifluoroacetamide, N, N-dimethyl-N-ethyl-N-propylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl- N-ethyl-N-butylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-pentylammonium bis (tri Fluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide N, N-dimethyl-N-ethyl-N-nonylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N, N-dipropylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl- N-propyl-N-butylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N- Hexyl ammo Umbis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-butyl-N-hexylammonium bis (trifluoromethanesulfonyl) Imido, N, N-dimethyl-N-butyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-pentyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N- Dimethyl-N, N-dihexylammonium bis (trifluoromethanesulfonyl) imide, trimethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-propylammonium Sus (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-heptylammonium bis (trifluoromethanesulfonyl) Imido, N, N-diethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, triethylpropylammonium bis (trifluoromethanesulfonyl) imide, triethylpentylammonium bis (trifluoromethanesulfonyl) imide, triethylheptylammonium bis (Trifluoromethanesulfonyl) imide, N, N-dipropyl-N-methyl-N-ethylammonium bis (trifluoromethanesulfonyl) imide, N, N- Dipropyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N-butyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N, N -Dihexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dibutyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dibutyl-N-methyl-N-hexylammonium bis (trifluoro) Romethanesulfonyl) imide, trioctylmethylammonium bis (trifluoromethanesulfonyl) imide, N-methyl-N-ethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide and the like. It is.

  The blending amount of the antistatic agent (D) is 0 to 10 parts by mass, preferably 0.1 to 8 parts by mass, more preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the acrylic polymer (A). It is.

  When the pressure-sensitive adhesive composition is used to form a pressure-sensitive adhesive layer when the blending amount is in the range of 0.1 to 8 parts by mass, the pressure-sensitive adhesive layer is improved while preventing charge between adherends and improving workability. It is preferable because good adhesive properties can be exhibited.

Other additives (E)
The pressure-sensitive adhesive composition of the present invention may optionally contain various additives as long as the physical properties when forming the pressure-sensitive adhesive layer are not impaired. Specific examples of such additives (E) include tackifier resins, tackifiers, antioxidants, ultraviolet absorbers, organic particles, inorganic particles, and the like. Alternatively, two or more kinds can be used in combination.

Preparation method of pressure-sensitive adhesive layer The pressure-sensitive adhesive composition of the present invention usually has a crosslinking agent (B), a silane coupling agent (C) or an antistatic agent (as required) for the above-mentioned acrylic polymer (A). D) are prepared by mixing simultaneously or in any order. In addition, when the acrylic polymer (A) and the crosslinking agent (B) component are mixed, when the acrylic polymer (A) is prepared by solution polymerization, the solution containing the acrylic polymer (A) after the polymerization is completed. A crosslinking agent (B) may be added.

  A pressure-sensitive adhesive layer in the form of a double-sided pressure-sensitive adhesive tape is prepared by casting the adhesive composition thus obtained on a release film, drying it, or irradiating it with active energy rays as necessary. Alternatively, the pressure-sensitive adhesive composition may be formed directly on the protective layer by casting or drying the pressure-sensitive adhesive composition directly on the above-mentioned protective layer, or by irradiating active energy rays.

  The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is usually 1 to 50 μm, preferably about 5 to 30 μm.

Storage elastic modulus of pressure-sensitive adhesive layer The pressure-sensitive adhesive layer of the present invention has a storage elastic modulus (G ′) at 23 ° C. and a measurement frequency of 1 Hz of 1.0 × 10 ^{4 to} 3.0 × 10 ⁵ Pa. Preferably, it is 3.0 × 10 ^{4 to} 2.8 × 10 ⁵ Pa, more preferably 5.0 × 10 ^{4 to} 2.6 × 10 ⁵ Pa.

In addition, the pressure-sensitive adhesive layer of the present invention preferably has a storage elastic modulus (G ′) of 7.5 × 10 ^{3 to} 1.5 × 10 ⁵ Pa at 80 ° C. and a measurement frequency of 1 Hz. It is more preferable that it is * 10 < ⁴ > -1.3 * 10 < ⁵ > Pa.

The pressure-sensitive adhesive layer of the present invention has a storage elastic modulus at 23 ° C. in the above range and a storage elastic modulus at 80 ° C. in the range of 7.5 × 10 ^{3 to} 1.5 × 10 ⁵ Pa. If it exists, it can be set as the polarizing plate with an adhesive layer which does not produce a float and peeling even in a severe environment.

Gel fraction of the pressure-sensitive adhesive layer The gel fraction of the pressure-sensitive adhesive layer of the present invention is not particularly limited, but is usually 60 to 90% by mass.

  In adjusting the gel fraction, it can be appropriately adjusted according to the type and amount of the crosslinkable functional group-containing monomer (a) constituting the pressure-sensitive adhesive composition and the type and amount of the crosslinking agent (B).

<Method for producing polarizing plate with pressure-sensitive adhesive layer>
Hereinafter, a polarizing plate with an adhesive layer according to one embodiment of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the polarizing plate (10) with an adhesive layer by one embodiment of this invention is the above-mentioned layered polarizer (20), an adhesive layer (30), a protective layer (40), and an adhesive. A layer (50), wherein at least one surface (20a) of the layered polarizer is in contact with one surface (30b) of the adhesive layer and the other surface (30a) of the adhesive layer. Is in contact with one surface (40b) of the protective layer (40), and one surface (50b) of the pressure-sensitive adhesive layer is in contact with the other surface (40a) of the protective layer.

  An optional protective layer (41) is further provided on the surface (20b) of the layered polarizer (20) that is not in contact with the adhesive layer (30) via an adhesive layer (31). You may make it stick. In this case, the adhesive layer (31) and the optional protective layer (41) may be made of the same material as the adhesive layer (30) and the protective layer (40), respectively, and are made of different materials. Also good.

  Furthermore, the sheet-like material (60) may be stuck on the other surface (50a) of the pressure-sensitive adhesive layer. In this case, the sheet-like material (60) may be a release film (separator) or various optical members made of resin or glass.

  In producing the polarizing plate with the pressure-sensitive adhesive layer according to one embodiment of the present invention, an adhesive layer is applied on the layered polarizer, or a double-sided adhesive tape-like adhesive layer is adhered, and the layered A polarizer and a protective layer may be attached.

  Further, a pressure-sensitive adhesive layer may be applied to the surface of the protective layer that is not in contact with the adhesive layer, or a double-sided tape-shaped pressure-sensitive adhesive layer prepared in advance may be attached.

  In addition, when applying and forming the pressure-sensitive adhesive layer, it may be formed by casting and drying a viscous solution-like pressure-sensitive adhesive composition, or curing by irradiating active energy rays after application, It is good also as an adhesive layer.

  EXAMPLES Hereinafter, although this invention is demonstrated based on the following Example, this invention is not limited to an Example.

  <Preparation of acrylic polymer (A)>

Production Example 1 (Preparation of acrylic polymer 1)
In a flask equipped with a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 96.8 parts by mass of n-butyl acrylate, 0.2 parts by mass of acrylic acid, and 3 parts by mass of 2-hydroxyethyl acrylate And 140 parts by mass of ethyl acetate were charged, and the contents of the flask were heated to 70 ° C. while introducing nitrogen gas into the flask. Next, 0.1 part by mass of AIBN was added with stirring to the flask sufficiently substituted with nitrogen gas.

  The reaction was carried out for 8 hours while maintaining the temperature of the contents in the flask at 70 ° C. After 8 hours, 140 parts of ethyl acetate was added to the reaction mixture to obtain an acrylic polymer 1.

  The acrylic polymer 1 obtained had a weight average molecular weight of 1.8 million as measured by gel permeation chromatography (GPC), the dispersion index of the acrylic polymer 1 was 5, and the calculated acid value was 1.6. Met.

    Production Examples 2 to 11 (Preparation of acrylic polymers 2 to 11)

  Acrylic polymers 2 to 11 were prepared in the same procedure as in Production Example 1 except that the raw material monomers described in Table 1 below were used.

In addition to the raw material monomers of the obtained acrylic polymers 1 to 11, the weight average molecular weight of each polymer is also listed in Table 1 below.

In addition, the abbreviation in Table 1 has the following meaning.
BA: butyl acrylate BzA: benzyl acrylate LA: lauryl acrylate LMA: lauryl methacrylate iSTA: isostearyl acrylate AA: acrylic acid 2-HEA: 2-hydroxyethyl acrylate

  Moreover, the acid value of the acrylic polymer was calculated by the following formula, and the weight average molecular weight of the acrylic polymer was measured by the following procedure.

<Acid value calculation procedure>
Acid value of acrylic polymer (mgKOH / g) = 561 / Y × X
Molecular weight of the carboxyl group-containing monomer used for copolymerization (X)
Compounding amount of carboxyl group-containing monomer (Y mass%)

<Measurement procedure of weight average molecular weight and dispersion index>
The weight average molecular weight (Mw) and the dispersion index (Mw / Mn) of the acrylic polymer (A) are determined by using GPC (gel permeation chromatography) and the weight average molecular weight (Mw) in terms of standard polystyrene under the following conditions. It is a thing.

<GPC measurement conditions>
Measuring device: HLC-8120GPC (manufactured by Tosoh Corporation)
GPC column configuration: The following five columns (all manufactured by Tosoh Corporation)
(I) TSK-GEL HXL-H (guard column)
(Ii) TSK-GEL G7000HXL
(Iii) TSK-GEL GMHXL
(Iv) TSK-GEL GMHXL
(V) TSK-GEL G2500HXL
Sample concentration: diluted with tetrahydrofuran to 1.0 mg / cm ³ Mobile phase solvent: tetrahydrofuran Flow rate: 1.0 cm ³ / min
Column temperature: 40 ° C

<Preparation of polarizing plate with adhesive layer>
Example 1 (Preparation of polarizing plate test piece 1)
To 100 parts by mass of the acrylic polymer (A) of Production Example 1, the components described in Table 2 described below were blended and mixed. After bubble removal, it was cast onto a PET separator using a doctor blade and dried at 90 ° C. for 3 minutes to prepare a pressure-sensitive adhesive layer having a thickness of 25 mm.

  After drying the pressure-sensitive adhesive layer, a polarizing plate having a protective layer made of acrylic resin on one side and a protective layer made of TAC as an optional protective layer on the other side is made of the acrylic resin The obtained pressure-sensitive adhesive layer was adhered to the protective layer side and allowed to stand for 1 to 7 days under conditions of a room temperature of 23 ° C. and a humidity of 65%.

  Thereafter, the polarizing plate is cut into a size of 150 mm × 250 mm, and then the PET separator is peeled off to expose the surface of the pressure-sensitive adhesive layer that is not in contact with the protective layer. The surface was bonded to a glass plate to produce a pressure-sensitive adhesive layer-attached polarizing plate test piece 1 (glass plate and polarizing plate with a pressure-sensitive adhesive layer) of Example 1.

  That is, this test piece is formed by laminating a glass plate, an adhesive layer, and a polarizing plate (a protective layer, an adhesive layer and a layered polarizer) in this order, and the thickness of the layered polarizer used. Is 10 μm, the thickness of the protective layer made of acrylic resin is 40 μm, and the thickness of the protective layer made of TAC as an optional protective layer is 40 μm.

  The test piece was subjected to a heat resistance durability test at 80 ° C./23 RH% for 500 hours and a moisture heat resistance durability test at 80 ° C./95 RH% for 500 hours. The results are shown in Table 2 below.

    Examples 2 to 11 and Comparative Examples 1 to 4 (Preparation of polarizing plate test pieces 2 to 15)

  Except having used the polymer of Table 1, and having set it as the mixing | blending of Table 2, it produced the polarizing plate test pieces 2-15 (a glass plate and a polarizing plate with an adhesive layer) with an adhesive layer in the procedure similar to Example 1. In the same manner, a heat durability test and a moisture heat durability test were conducted. The results are also shown in Table 2 below.

In addition, the evaluation criteria of the heat durability test and the moisture heat resistance test are as follows.
(Standard)
S: No defect A: Defect area less than 1%, no problem in practical use B: Defect area of 1% or more, less than 3%, no problem in practical use C: Defect area of 3% or more, less than 5%, no problem in practical use D : Defect area is 5% or more

<Measurement of storage modulus>
When measuring the storage elastic modulus, a plurality of each adhesive layer used for the test pieces of Examples 1 to 11 and Comparative Examples 1 to 4 were prepared, and the storage elastic modulus was measured to have a thickness of 1 mm by laminating them. A test piece was prepared. Using this test piece, a storage elastic modulus (G ′) was measured using a modular compact rheometer MCR300 manufactured by Anton Paar. The measurement frequency was 1 Hz. The measurement results are also shown in Table 2 below.

In addition, the abbreviation in Table 2 has the following meaning.
L-45: Tolylene diisocyanate crosslinking agent (manufactured by Soken Chemical Co., Ltd.)
E-5XM: Epoxy crosslinking agent (manufactured by Soken Chemical Co., Ltd.)
A-50: Silane coupling agent (manufactured by Soken Chemical Co., Ltd.)
AS-A: 1-octyl-4-methylpyridinium bis (fluorosulfonyl) imide AS-B: tributylmethylammonium trifluoromethanesulfonylimide

DESCRIPTION OF SYMBOLS 10 Polarizing plate with adhesive layer 20 Layered polarizer 30 Adhesive layer 31 Adhesive layer 40 Protective layer 41 Optional protective layer 50 Adhesive layer 60 Sheet-like material

Claims (6)

A polarizing plate with an adhesive layer having a layered polarizer containing a polyvinyl alcohol resin, an adhesive layer, a protective layer made of a (meth) acrylic resin composition, and an adhesive layer, wherein the layered polarizer is At least one surface is in contact with one surface of the adhesive layer, the other surface of the adhesive layer is in contact with one surface of the protective layer, and one surface of the adhesive layer is the protective layer. The pressure-sensitive adhesive layer is in contact with the other surface of the monomer (a), more than 0 part by mass and less than 6 parts by mass of the monomer (a) having a crosslinkable functional group, and an alkyl (meth) acrylic group having 8 or more carbon atoms in the alkyl chain. The acrylic polymer (A) having a weight average molecular weight of 600,000 to 3,000,000, which is obtained by copolymerizing a monomer mixture containing 0 to 99.5 parts by mass of the monomer (b), The acid value is 1-50 mg KOH / g, 23 ° C. of the adhesive layer, measuring the pressure-sensitive adhesive layer-attached polarizing plate, wherein the storage modulus at a frequency 1 Hz (G') is ^{1.0 × 10 4 ~3.0 × 10 5} Pa.   The pressure-sensitive adhesive according to claim 1, wherein the monomer (a) having a crosslinkable functional group is a (meth) acrylic monomer having a hydroxyl group and / or a (meth) acrylic monomer having a carboxyl group. Layered polarizing plate.   The said adhesive layer contains a crosslinking agent (B), The polarizing plate with an adhesive layer of Claim 1 or 2 characterized by the above-mentioned.   The said adhesive layer contains a silane coupling agent (C), The polarizing plate with an adhesive layer of any one of Claims 1-3 characterized by the above-mentioned. The pressure-sensitive adhesive layer, 80 ° C., and wherein the storage modulus at a measuring frequency of 1 Hz (G') is ^{7.5 × 10 3 ~1.5 × 10 5} Pa, any claim 1 to 4 The polarizing plate with an adhesive layer of Claim 1.   The said adhesive layer has a gel fraction of 60-90 mass%, The polarizing plate with an adhesive layer of any one of Claims 1-5 characterized by the above-mentioned.