WO2015141381A1 - 偏光板用粘着剤組成物、粘着剤層、粘着シートおよび粘着剤層付き偏光板 - Google Patents
偏光板用粘着剤組成物、粘着剤層、粘着シートおよび粘着剤層付き偏光板 Download PDFInfo
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- WO2015141381A1 WO2015141381A1 PCT/JP2015/054776 JP2015054776W WO2015141381A1 WO 2015141381 A1 WO2015141381 A1 WO 2015141381A1 JP 2015054776 W JP2015054776 W JP 2015054776W WO 2015141381 A1 WO2015141381 A1 WO 2015141381A1
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- sensitive adhesive
- pressure
- polarizing plate
- meth
- adhesive layer
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
- G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
- C09J133/04—Homopolymers or copolymers of esters
- C09J133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
- C09J133/062—Copolymers with monomers not covered by C09J133/06
- C09J133/066—Copolymers with monomers not covered by C09J133/06 containing -OH groups
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/10—Esters
- C08F220/20—Esters of polyhydric alcohols or phenols, e.g. 2-hydroxyethyl (meth)acrylate or glycerol mono-(meth)acrylate
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/40—High-molecular-weight compounds
- C08G18/62—Polymers of compounds having carbon-to-carbon double bonds
- C08G18/6216—Polymers of alpha-beta ethylenically unsaturated carboxylic acids or of derivatives thereof
- C08G18/622—Polymers of esters of alpha-beta ethylenically unsaturated carboxylic acids
- C08G18/6225—Polymers of esters of acrylic or methacrylic acid
- C08G18/6229—Polymers of hydroxy groups containing esters of acrylic or methacrylic acid with aliphatic polyalcohols
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/80—Masked polyisocyanates
- C08G18/8003—Masked polyisocyanates masked with compounds having at least two groups containing active hydrogen
- C08G18/8006—Masked polyisocyanates masked with compounds having at least two groups containing active hydrogen with compounds of C08G18/32
- C08G18/8009—Masked polyisocyanates masked with compounds having at least two groups containing active hydrogen with compounds of C08G18/32 with compounds of C08G18/3203
- C08G18/8022—Masked polyisocyanates masked with compounds having at least two groups containing active hydrogen with compounds of C08G18/32 with compounds of C08G18/3203 with polyols having at least three hydroxy groups
- C08G18/8029—Masked aromatic polyisocyanates
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
- C08K5/0025—Crosslinking or vulcanising agents; including accelerators
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/04—Oxygen-containing compounds
- C08K5/14—Peroxides
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
- C09J175/04—Polyurethanes
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
- C09J175/04—Polyurethanes
- C09J175/14—Polyurethanes having carbon-to-carbon unsaturated bonds
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J7/00—Adhesives in the form of films or foils
- C09J7/20—Adhesives in the form of films or foils characterised by their carriers
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
- G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
- G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J2203/00—Applications of adhesives in processes or use of adhesives in the form of films or foils
- C09J2203/318—Applications of adhesives in processes or use of adhesives in the form of films or foils for the production of liquid crystal displays
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2202/00—Materials and properties
- G02F2202/28—Adhesive materials or arrangements
Definitions
- the present invention relates to a pressure-sensitive adhesive composition for polarizing plates.
- the liquid crystal cell has a structure in which a liquid crystal layer is sandwiched between two substrates (eg, a glass plate), and a polarizing plate is attached to the surface of the substrate via an adhesive layer.
- a polarizing plate is likely to be thermally contracted in a high temperature and high humidity environment, so that it lacks dimensional stability and may cause warpage in a liquid crystal cell.
- the thinning of liquid crystal cells eg, thinning of the substrate constituting the liquid crystal cell
- the thinning of the polarizing plate the warpage of the liquid crystal cell under a high temperature and high humidity environment has become a larger problem.
- the pressure-sensitive adhesive layer cannot follow the thermal contraction (dimensional change) of the polarizing plate, and the stress relaxation property of the pressure-sensitive adhesive layer is low.
- Patent Documents 1 and 2 when a triacetyl cellulose (TAC) substrate and a glass substrate are laminated via an adhesive layer, the adhesive film of the TAC substrate is removed from the glass substrate under high temperature and high humidity.
- a pressure-sensitive adhesive layer containing an acrylic pressure-sensitive adhesive, an isocyanate-based curing agent, and an acrylic copolymer, the pressure-sensitive adhesive layer having a specific range of loss tangent (tan ⁇ ). It is disclosed.
- An object of the present invention is to provide a pressure-sensitive adhesive composition for a polarizing plate capable of suppressing a warp (bending) of a liquid crystal cell and capable of forming a pressure-sensitive adhesive layer excellent in durability, and a polarizing plate formed from the composition. It is in providing the adhesive layer for polarizing plates, the adhesive sheet for polarizing plates which has the said adhesive layer, and the polarizing plate with an adhesive layer which has the said adhesive layer.
- a pressure-sensitive adhesive composition containing a specific (meth) acrylic copolymer and a crosslinking agent, and the loss tangent at 23 ° C. and 80 ° C. of the pressure-sensitive adhesive layer formed from the composition are specified. It was found that the pressure-sensitive adhesive composition within the range can suppress the warping (bending) of the liquid crystal cell and can form a pressure-sensitive adhesive layer excellent in durability. That is, the present inventors have found that the above problems can be solved by using a polarizing plate pressure-sensitive adhesive composition having the following specific configuration, and have completed the present invention.
- the present invention includes, for example, the following [1] to [12].
- [1] (A) a (meth) acrylic copolymer obtained by copolymerizing a monomer component containing a (meth) acrylic acid alkyl ester having 4 to 18 carbon atoms in an alkyl group and a polar group-containing monomer; B) A pressure-sensitive adhesive composition for a polarizing plate containing a crosslinking agent, and a loss tangent (tan ⁇ 1 ) at 23 ° C. of the pressure-sensitive adhesive layer formed from the composition is 0.33 to 0.55, And a loss tangent (tan ⁇ 2 ) at 80 ° C. of 0.40 to 0.65.
- the weight average molecular weight (Mw) of the (meth) acrylic copolymer (A) measured by a gel permeation chromatography method (GPC method) is 200,000 to 1,500,000, [1]
- a pressure-sensitive adhesive sheet for polarizing plates comprising the pressure-sensitive adhesive layer for polarizing plates according to [9] or [10].
- a polarizing plate with a pressure-sensitive adhesive layer comprising a polarizing plate and the polarizing plate pressure-sensitive adhesive layer according to [9] or [10] formed on at least one surface of the polarizing plate.
- the adhesive composition for polarizing plates which can suppress the curvature (bending) of a liquid crystal cell and can form the adhesive layer excellent in durability
- the polarizing plate formed from the said composition
- the adhesive layer for polarizing plates, the adhesive sheet for polarizing plates which has the said adhesive layer, and the polarizing plate with an adhesive layer which has the said adhesive layer can be provided.
- the pressure-sensitive adhesive composition for polarizing plate is also simply referred to as “pressure-sensitive adhesive composition”
- the pressure-sensitive adhesive layer for polarizing plates of the present invention is also simply referred to as “pressure-sensitive adhesive layer”.
- the sheet is also simply referred to as “adhesive sheet”.
- the pressure-sensitive adhesive composition for polarizing plates of the present invention is a composition containing a (meth) acrylic copolymer (A) and a crosslinking agent (B), and is a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition.
- the loss tangent (tan ⁇ 1 ) at 23 ° C. is 0.33 to 0.55
- the loss tangent (tan ⁇ 2 ) at 80 ° C. is 0.40 to 0.65.
- the pressure-sensitive adhesive composition of the present invention may contain at least one selected from a silane coupling agent (C), an antistatic agent (D), and an organic solvent (E) as necessary.
- a silane coupling agent (C) silane coupling agent
- D antistatic agent
- E organic solvent
- an adhesive layer having a thickness of 1.0 mm formed under the following conditions was subjected to dynamic viscosity based on JIS K7244 using “Physica MCR300” manufactured by Anton Paar. Loss tangent can be obtained by measuring the viscoelastic spectrum by an elastic measurement method (temperature range ⁇ 40 to 180 ° C., temperature rising rate 3.67 ° C./min, frequency 1 Hz).
- the pressure-sensitive adhesive layer in the dynamic viscoelasticity measurement is formed as follows.
- the pressure-sensitive adhesive composition is applied onto a release-treated polyethylene terephthalate film (PET film) so that the thickness after drying is 20 ⁇ m, and dried at 90 ° C. for 3 minutes to remove the solvent and form a coating film.
- PET film release-treated polyethylene terephthalate film
- the peeled PET film is further bonded to the surface of the coating film opposite to the surface of the PET film, and the film is aged in a 23 ° C./50% RH environment for 7 days to form a 20 ⁇ m thick adhesive layer. To do.
- the PET film on one side of the obtained pressure-sensitive adhesive sheet is peeled off, and the pressure-sensitive adhesive layers having a thickness of 20 ⁇ m are bonded to each other multiple times to form a pressure-sensitive adhesive layer having a final thickness of 1.0 mm. And the said viscoelastic spectrum is measured about this adhesive layer.
- the said formation conditions of an adhesive layer are described in order to measure the loss tangent as a characteristic of the adhesive composition of this invention,
- the adhesive layer formed from the adhesive composition of this invention is Of course, the layer is not limited to the above condition.
- the loss tangent (tan ⁇ ) is expressed by the ratio of the storage elastic modulus G ′ indicating elastic properties to the loss elastic modulus G ′′ indicating viscous properties: G ′′ / G ′, and the larger the value, the greater the contribution of viscosity. The smaller the value, the greater the contribution of elasticity.
- the loss tangent (tan ⁇ 1 ) at 23 ° C. is 0.33 to 0.55, preferably 0.35 to 0.52, particularly preferably 0.40 to 0.49;
- the loss tangent (tan ⁇ 2 ) is 0.40 to 0.65, preferably 0.42 to 0.62, and particularly preferably 0.47 to 0.56.
- the pressure-sensitive adhesive layer is excellent in flexibility and can follow the thermal contraction (dimensional change) of the polarizing plate at a high temperature.
- tan ⁇ 2 exceeds the above range, the cohesiveness of the pressure-sensitive adhesive layer is lowered, and the durability tends not to be obtained. If tan ⁇ 2 is less than the above range, the pressure-sensitive adhesive layer cannot follow the thermal contraction (dimensional change) of the polarizing plate at a high temperature, and there is a tendency for the polarizing plate to warp or the pressure-sensitive adhesive layer to tear.
- the pressure-sensitive adhesive layer, 23 the ratio of the loss tangent (tan [delta 2) in the loss tangent (tan [delta 1) and 80 ° C. at °C (tan ⁇ 2 / tan ⁇ 1) is preferably 1.10 or more, more preferably 1.10 To 5.0, more preferably 1.10 to 2.0.
- the ratio of the loss tangent is in the above range, the pressure-sensitive adhesive layer becomes highly flexible at a high temperature and can follow the thermal contraction (dimensional change) of the polarizing plate.
- a pressure-sensitive adhesive layer having a loss tangent (tan ⁇ 1 , tan ⁇ 2 ) in the above range for example, a (meth) acrylic copolymer (A) described below as a component of the pressure-sensitive adhesive composition and And a crosslinking agent (B) such as an isocyanate compound (B1) and a metal chelate compound (B2).
- B crosslinking agent
- the gel fraction of the pressure-sensitive adhesive formed from the pressure-sensitive adhesive composition of the present invention is preferably 10 to 70% by mass, more preferably 15 to 65% by mass, and further preferably 20 to 60% by mass.
- the said gel fraction is a value measured about the adhesive extract
- the pressure-sensitive adhesive composition of the present invention has the above properties, it is suitable for use in bonding a substrate constituting a liquid crystal cell and a polarizing plate.
- the thickness of the glass plate constituting the thinned liquid crystal cell is as small as about 0.1 to 1.0 mm, it is suitable for bonding the substrate and the polarizing plate.
- the (meth) acrylic copolymer (A) is a copolymer obtained by copolymerizing a monomer component containing a (meth) acrylic acid alkyl ester having an alkyl group having 4 to 18 carbon atoms and a polar group-containing monomer. It is.
- Examples of the monomer component of the copolymer (A) include other monomers.
- acrylic and methacryl are collectively referred to as “(meth) acryl”.
- structural unit derived from a certain monomer a contained in the polymer is also referred to as “monomer a unit”.
- (Meth) acrylic acid alkyl ester As the (meth) acrylic acid alkyl ester, a (meth) acrylic acid alkyl ester having an alkyl group having 4 to 18 carbon atoms (CH 2 ⁇ CR 1 —COOR 2 ; R 1 is a hydrogen atom or a methyl group, R 2 Is an alkyl group having 4 to 18 carbon atoms), and the alkyl group preferably has 4 to 12 carbon atoms.
- Examples of the (meth) acrylic acid alkyl ester having 4 to 18 carbon atoms in the alkyl group include, for example, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, Hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undeca (meth) acrylate, Examples include lauryl (meth) acrylate, stearyl (meth) acrylate, and isostearyl (meth) acrylate. These may be used alone or in combination of two or more.
- the total amount of the alkyl (meth) acrylic acid alkyl ester having 4 to 18 carbon atoms in the alkyl group is good adhesive strength and durability. In view of the above, it is preferably 99.8 to 20% by mass, more preferably 99.5 to 30% by mass, and still more preferably 99 to 50% by mass.
- a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 3 carbon atoms (CH 2 ⁇ CR 3 —COOR 4 ; R 3 is a hydrogen atom or methyl And R 4 is an alkyl group having 1 to 3 carbon atoms).
- Examples of the (meth) acrylic acid alkyl ester having 1 to 3 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and isopropyl (meth) acrylate. . These may be used alone or in combination of two or more.
- the amount of (meth) acrylic acid alkyl ester having 1 to 3 carbon atoms in the alkyl group is preferably 60% by mass or less, more preferably 50% by mass or less in 100% by mass of the monomer component from the viewpoint of stress relaxation characteristics. More preferably, it is 40 mass% or less.
- polar group-containing monomer examples include a hydroxyl group-containing monomer, an acid group-containing monomer, an amino group-containing monomer, an amide group-containing monomer, a nitrogen-based heterocyclic ring-containing monomer, and a cyano group-containing monomer.
- the acid group examples include a carboxyl group, an acid anhydride group, a phosphoric acid group, and a sulfuric acid group.
- the polar group-containing monomer it is preferable to use a monomer having a polar group (crosslinkable functional group) capable of reacting with the crosslinkable functional group of the crosslinking agent (B).
- the polar group is a carboxyl group and / or a hydroxyl group from the viewpoint of efficiently obtaining a crosslinked structure, easily obtaining good durability, and further improving the adhesion of the substrate to an optical film such as a polarizing plate. It is preferable to use a monomer, that is, to use at least one selected from a carboxyl group-containing monomer and a hydroxyl group-containing monomer.
- hydroxyl group-containing monomer examples include a hydroxyl group-containing (meth) acrylate, and specific examples include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate.
- hydroxyalkyl (meth) acrylates such as 6-hydroxyhexyl (meth) acrylate and 8-hydroxyoctyl (meth) acrylate.
- the number of carbon atoms of the hydroxyalkyl group in the hydroxyalkyl (meth) acrylate is usually 2 to 8, preferably 2 to 6.
- a hydroxyl-containing monomer may be used individually by 1 type, and may use 2 or more types.
- the hydroxyl group contained in the hydroxyl group-containing monomer functions as a crosslinkable functional group with an isocyanate group contained in the isocyanate compound (B1), for example.
- the amount of the hydroxyl group-containing monomer used is preferably 0 to 15% by mass, more preferably 0.05 to 10% by mass, and further preferably 0.1 to 7% by mass in 100% by mass of the monomer component.
- the amount of the hydroxyl group-containing monomer is less than or equal to the above upper limit, the crosslink density formed by the (meth) acrylic copolymer (A) and the isocyanate compound (B1) does not become too high, and the stress relaxation characteristics are excellent.
- An adhesive layer is obtained.
- the amount of the hydroxyl group-containing monomer used is equal to or more than the lower limit, a crosslinked structure is effectively formed, and a pressure-sensitive adhesive layer having an appropriate strength at room temperature
- carboxyl group-containing monomer examples include ⁇ -carboxyethyl (meth) acrylate, 5-carboxypentyl (meth) acrylate, mono (meth) acryloyloxyethyl ester succinate, and ⁇ -carboxypolycaprolactone mono (meth) acrylate.
- Carboxyl group-containing (meth) acrylates such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, fumaric acid, and maleic acid.
- acid anhydride group-containing monomer examples include maleic anhydride and itaconic anhydride.
- Examples of the phosphate group-containing monomer include (meth) acrylic monomers having a phosphate group in the side chain, and examples of the sulfate group-containing monomer include (meth) acrylic monomers having a sulfate group in the side chain.
- the acid group contained in the acid group-containing monomer functions as a crosslinkable functional group with, for example, an isocyanate compound (B1) or a metal chelate compound (B2).
- the amount of the acid group-containing monomer used is preferably 0 to 15% by mass, more preferably 0.05 to 10% by mass, and further preferably 0.1 to 5% by mass in 100% by mass of the monomer component.
- the acid value of the (meth) acrylic copolymer (A) is preferably 0 to 117 mgKOH / g, more preferably 0.4 to 78 mgKOH / g.
- the amount of the acid group-containing monomer used is less than or equal to the above upper limit, the crosslinking density formed by the (meth) acrylic copolymer (A) and the crosslinking agent (B) does not become too high, resulting in stress relaxation characteristics. An excellent pressure-sensitive adhesive layer is obtained.
- the amount of the acid group-containing monomer used is equal to or higher than the lower limit, a crosslinked structure is effectively formed, and a pressure-sensitive adhesive layer having an appropriate strength at room temperature can be obtained.
- Examples of the amino group-containing monomer include amino group-containing (meth) acrylates such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate.
- Examples of the amide group-containing monomer include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, and N-hexyl (meth) acrylamide.
- Examples of the nitrogen heterocycle-containing monomer include vinyl pyrrolidone, acryloyl morpholine, and vinyl caprolactam.
- Examples of the cyano group-containing monomer include cyano (meth) acrylate and (meth) acrylonitrile.
- a polar group containing monomer may be used individually by 1 type, and may use 2 or more types.
- the monomer component that forms the (meth) acrylic copolymer (A) is a range that does not impair the physical properties of the (meth) acrylic copolymer (A).
- Other (meth) acrylic esters such as mono (meth) acrylates, alicyclic groups or aromatic ring-containing (meth) acrylates can be included.
- alkoxyalkyl (meth) acrylate examples include methoxymethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, 3-ethoxypropyl ( And (meth) acrylate, 4-methoxybutyl (meth) acrylate, and 4-ethoxybutyl (meth) acrylate.
- alkoxypolyalkylene glycol mono (meth) acrylate examples include methoxydiethylene glycol mono (meth) acrylate, methoxydipropylene glycol mono (meth) acrylate, ethoxytriethylene glycol mono (meth) acrylate, ethoxydiethylene glycol mono (meth) acrylate, And methoxytriethylene glycol mono (meth) acrylate.
- Examples of the alicyclic group or aromatic ring-containing (meth) acrylate include cyclohexyl (meth) acrylate, benzyl (meth) acrylate, and phenyl (meth) acrylate.
- the total amount of the other (meth) acrylic acid ester used is preferably 60% by mass or less, more preferably 40% by mass or less, in 100% by mass of the monomer component.
- the physical properties of the (meth) acrylic copolymer (A) are not impaired, for example, styrene, methylstyrene, dimethylstyrene, trimethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene and octylstyrene.
- Styrenic monomers such as alkyl styrene, fluoro styrene, chloro styrene, bromo styrene, dibromo styrene, iodinated styrene, nitro styrene, acetyl styrene and methoxy styrene, etc .; copolymerizable monomers such as vinyl acetate can also be used it can.
- the total amount of the copolymerizable monomer used in the copolymerization is preferably 40% by mass or less, more preferably 20% by mass or less, in 100% by mass of the monomer component.
- Other monomers may be used alone or in combination of two or more.
- the (meth) acrylic copolymer (A) is preferably a copolymer obtained by the above copolymerization in the presence of a peroxide polymerization initiator.
- a peroxide-based polymerization initiator as the polymerization initiator, polymer molecules with many branches tend to be obtained. For this reason, (1) entanglement caused by branched chains between polymer molecules occurs frequently at about room temperature, and as a result, polymer cohesiveness is maintained even in designs where the molecular weight of the polymer and the gel fraction of the adhesive layer are low.
- a pressure-sensitive adhesive layer having excellent storage properties such as pressure-sensitive adhesive properties, processability such as punching out the pressure-sensitive adhesive layer, and less deformation and protrusion of the pressure-sensitive adhesive layer; (2) polymer molecules at high temperatures (eg 60 ° C.) Since the mutual entanglement partly loosens, the temperature dependency of the degree of increase in the viscosity property of the pressure-sensitive adhesive layer is high, and the pressure-sensitive adhesive layer exhibits excellent flexibility. Therefore, the pressure-sensitive adhesive layer exhibits excellent durability due to the entanglement that remains partially while being excellent in suppressing the warping (bending) of the polarizing plate.
- the metal chelate compound (B2) described later when used as a part of the crosslinking agent (B), the (meth) acrylic copolymer (A) / metal chelate compound (B2) Crosslinks are formed by coordination bonds between them (pseudocrosslinking). For this reason, the crosslinking is maintained at the room temperature and the polymer exhibits cohesiveness, whereas the crosslinking is partially released at the high temperature, and the pressure-sensitive adhesive layer tends to exhibit more excellent flexibility.
- the reason why the polymer molecules having many branches contribute to the suppression of the warpage of the polarizing plate is presumed to be as follows.
- a case where a glass plate is used as the adherend will be described as an example.
- the polarizing plate and the glass plate have different heat shrinkage rates, and the polarizing plate usually has a larger heat shrinkage rate (dimensional change) than the glass plate.
- the pressure-sensitive adhesive layer lacks flexibility under a high-temperature, high-humidity heat environment, the pressure-sensitive adhesive layer cannot follow the dimensional change of the polarizing plate, and the pressure-sensitive adhesive layer cannot relieve stress. Stress concentrates on the glass plate, which causes warpage of the glass plate.
- the entanglement is partially loosened under a high temperature and high humidity environment, and the crosslinking is partially released.
- the pressure-sensitive adhesive layer can follow the change. For this reason, stress does not generate
- the pressure-sensitive adhesive layer can absorb and relieve the stress associated with the dimensional change of the polarizing plate, so that excessive stress (load) is not applied to the glass plate, so that the warpage of the glass plate is suppressed. It is estimated that it will lead to
- the (meth) acrylic copolymer (A) can be produced by, for example, a conventionally known polymerization method such as a solution polymerization method, a bulk polymerization method, an emulsion polymerization method, a suspension polymerization method, etc. Legal is preferred. Specifically, a polymerization solvent and a monomer component are charged into a reaction vessel, a polymerization initiator is added in an inert gas atmosphere such as nitrogen gas, and the reaction start temperature is usually 40 to 100 ° C., preferably 50 to 80 ° C. The reaction system is maintained at a temperature of usually 50 to 90 ° C., preferably 70 to 90 ° C., and allowed to react for 4 to 20 hours.
- a conventionally known polymerization method such as a solution polymerization method, a bulk polymerization method, an emulsion polymerization method, a suspension polymerization method, etc. Legal is preferred.
- a polymerization solvent and a monomer component are charged into a reaction vessel,
- a peroxide polymerization initiator for example, Di (2-tert-butylperoxyisopropyl) benzene, dicumyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, tert-butylcumyl peroxide, di-tert-hexyl Dialkyl peroxides such as peroxide and di-tert-butyl peroxide (eg, compounds represented by R—O—O—R, wherein each R is independently an alkyl group or an aryl group-substituted alkyl group) A compound represented by R—O—O—A—O—O—R, wherein each R is independently an alkyl group or an aryl group-substituted alkyl group, and A is a divalent hydrocarbon group) ; Diisobutyryl peroxide, di (3,5,5-trimethylhexanoyl) peroxide, dil
- peroxide-based polymerization initiators peroxyesters are preferred because highly branched (meth) acrylic copolymers are obtained, and peroxide-based polymerization initiation represented by the following formula (1) An agent is more preferable.
- R A to R F are each independently a hydrogen atom, an alkyl group or an aryl group, and since a highly branched copolymer is obtained, preferably an alkyl group having 1 to 10 carbon atoms, It is a phenyl group, more preferably an alkyl group having 1 to 8 carbon atoms, still more preferably an alkyl group having 1 to 4 carbon atoms, and particularly preferably an alkyl group having 1 to 2 carbon atoms.
- tert-butyl peroxypivalate, tert-hexyl peroxypivalate, tert-butyl peroxyneodecanoate, tert-butyl peroxyneo Heptanoate, tert-butylperoxy-2-ethylhexanoate, and cumylperoxyneodecanoate are preferred, and a highly branched copolymer can be obtained, so that tert-butylperoxypivalate, tert- Hexyl peroxypivalate, tert-butyl peroxyneodecanoate, tert-butyl peroxyneoheptanoate, tert-butyl peroxy-2-ethylhexanoate are particularly preferred.
- One peroxide polymerization initiator may be used alone, or two or more peroxide polymerization initiators may be used. Moreover, adding a peroxide polymerization initiator a plurality of times during the polymerization is not limited. As a polymerization initiator, an azo initiator can be used together with a peroxide initiator as long as a highly branched copolymer is obtained.
- azo initiator examples include 2,2′-azobisisobutyronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2- Cyclopropylpropionitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbohydrate) Nitrile), 2- (carbamoylazo) isobutyronitrile, 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′- Azobis (N, N'-dimethyleneisobutylamidine), 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) -propionamide], 2,2'-azo (Isobutylamide) dihydrate, 4,4′-
- the peroxide polymerization initiator is usually 0.001 to 5 parts by mass, preferably 0.005 to 3 parts by mass with respect to 100 parts by mass of the monomer component forming the (meth) acrylic copolymer (A). Used in amounts within the range of Moreover, it is preferable not to use an azo initiator, and the amount used is preferably 0.5 parts by mass or less, more preferably 0.2 parts by mass or less, with respect to 100 parts by mass of the peroxide polymerization initiator. More preferably, it is 0 parts by mass. However, use for the purpose of reducing the residual monomer in the latter half of the reaction is not limited. Moreover, you may add suitably a polymerization initiator, a chain transfer agent, a monomer component, and a polymerization solvent during the said polymerization reaction.
- polymerization solvent used for the solution polymerization examples include aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane and n-octane; cyclopentane, Cycloaliphatic hydrocarbons such as cyclohexane, cycloheptane, cyclooctane; ethers such as diethyl ether, diisopropyl ether, 1,2-dimethoxyethane, dibutyl ether, tetrahydrofuran, dioxane, anisole, phenylethyl ether, diphenyl ether; chloroform, Halogenated hydrocarbons such as carbon tetrachloride, 1,2-dichloroethane, chlorobenzene; esters such as ethyl acetate, propyl acetate, butyl a
- the activation energy in the reaction R is the gas constant (8.314 J / mol ⁇ K), T is the absolute temperature (K), and t is the reaction time.
- the frequency factor (A) and the activation energy ( ⁇ E) have been determined.
- the values described in the NOF Corporation organic peroxide catalog (10th edition) Can be used.
- ⁇ E 119.1 kJ / mol
- A 6.93 ⁇ 10 17 hr ⁇ 1
- A 6.45 ⁇ 10 17 hr ⁇ 1
- the residual rate (%) of the peroxide polymerization initiator after the reaction for t hours at the predetermined temperature can be calculated according to the above formula. Therefore, the remaining amount of the peroxide-based polymerization initiator contained in the pressure-sensitive adhesive composition can be calculated by the amount of the peroxide-based polymerization initiator used in the copolymerization ⁇ the remaining rate (%).
- the (meth) acrylic copolymer (A) preferably has a weight average molecular weight (Mw) measured by a gel permeation chromatography method (GPC method) of 200,000 to 1,500,000 in terms of polystyrene. Is 400,000 to 1.3 million, more preferably 500,000 to 1.1 million.
- Mw weight average molecular weight measured by a gel permeation chromatography method
- GPC method gel permeation chromatography method
- the molecular weight distribution (Mw / Mn) measured by the GPC method of the (meth) acrylic copolymer (A) is usually 50 or less, preferably 30 or less, more preferably 20 or less.
- the (meth) acrylic copolymer (A) preferably has a degree of branching measured by the GPC-MALS method of 0.55 or less, more preferably 0.10 to 0.54, and even more preferably 0. 20 to 0.53, particularly preferably 0.30 to 0.53. Details of measurement conditions for the degree of branching are described in the examples. In order to adjust the loss tangent of the pressure-sensitive adhesive layer to the above range, it is preferable to use a copolymer (A) having a branching degree in the above range.
- the degree of branching is an index indicating a branched polymer when it is 0.55 or less and a linear polymer when it exceeds 0.55.
- a branched polymer when the degree of branching is small, it indicates that the polymer molecule has many branches and has a high degree of branching, and when the degree of branching is large, the polymer molecule has little branching and low degree of branching. It shows having.
- the glass transition temperature (Tg) of the (meth) acrylic copolymer (A) can be calculated by, for example, the Fox formula from the monomer units constituting the polymer and the content ratio thereof.
- the (meth) acrylic copolymer (A) is synthesized so that the glass transition temperature (Tg) determined by the Fox equation is usually ⁇ 70 to 0 ° C., preferably ⁇ 60 to ⁇ 30 ° C. Can do.
- Tg glass transition temperature
- Tg is a glass transition temperature of the (meth) acrylic copolymer (A)
- Tg 1 , Tg 2 ,..., Tg m are glass transition temperatures of homopolymers composed of the respective monomers
- W 1 , W 2 ,..., W m are weight fractions of the structural units derived from the respective monomers in the copolymer (A).
- glass transition temperature of the homopolymer composed of each monomer in the Fox formula for example, a value described in Polymer Handbook Fourth Edition (Wiley-Interscience 1999) can be used.
- the content of the (meth) acrylic copolymer (A) in the pressure-sensitive adhesive composition of the present invention is usually 50 to 99.99 in 100% by mass of the solid content excluding the organic solvent (E) in the composition. % By mass, more preferably 60 to 99.95% by mass, particularly preferably 80 to 99.90% by mass. When the content of the (meth) acrylic copolymer (A) is in the above range, the performance as an adhesive is balanced and the adhesive properties are excellent.
- Crosslinking agent (B) Although a crosslinking agent (B) will not be specifically limited if it is a component which can raise
- a crosslinking agent (B) may be used individually by 1 type, and may use 2 or more types.
- the crosslinking agents (B) it is preferable to use the isocyanate compound (B1) and the metal chelate compound (B2) in combination.
- the (meth) acrylic copolymer (A) is crosslinked with a covalent bond based on the isocyanate compound (B1) and the metal chelate compound (B2). It is preferred to form pseudo-crosslinks based on coordinate bonds based.
- the total content of the crosslinking agent (B) is preferably 0.01 to 5 parts by mass, more preferably 100 parts by mass of the (meth) acrylic copolymer (A). Is 0.05 to 2.5 parts by mass, more preferably 0.1 to 1 part by mass.
- Isocyanate compound (B1) an isocyanate compound having 2 or more isocyanate groups in one molecule is usually used.
- a crosslinked body (network polymer) can be formed by crosslinking the (meth) acrylic copolymer (A) with the isocyanate compound (B1).
- the number of isocyanate groups in the isocyanate compound (B1) is usually 2 or more, preferably 2 to 8, and more preferably 3 to 6. When the number of isocyanate groups is within the above range, it is preferable from the viewpoint of the crosslinking reaction efficiency between the (meth) acrylic copolymer (A) and the isocyanate compound (B1) and the flexibility of the pressure-sensitive adhesive layer.
- diisocyanate compound having 2 isocyanate groups in one molecule examples include aliphatic diisocyanate, alicyclic diisocyanate, and aromatic diisocyanate.
- Aliphatic diisocyanates include ethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 2-methyl-1,5-pentane diisocyanate, 3-methyl-1,5-pentane diisocyanate, 2,2,4-trimethyl
- aliphatic diisocyanates having 4 to 30 carbon atoms such as -1,6-hexamethylene diisocyanate.
- alicyclic diisocyanates include alicyclic rings having 7 to 30 carbon atoms such as isophorone diisocyanate, cyclopentyl diisocyanate, cyclohexyl diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and hydrogenated tetramethylxylylene diisocyanate.
- Group diisocyanates are examples of alicyclic rings having 7 to 30 carbon atoms such as isophorone diisocyanate, cyclopentyl diisocyanate, cyclohexyl diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and hydrogenated tetramethylxylylene diisocyanate.
- aromatic diisocyanate examples include aromatic diisocyanates having 8 to 30 carbon atoms such as phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, naphthylene diisocyanate, diphenyl ether diisocyanate, diphenylmethane diisocyanate, and diphenylpropane diisocyanate.
- isocyanate compound having 3 or more isocyanate groups in one molecule examples include aromatic polyisocyanate, aliphatic polyisocyanate, and alicyclic polyisocyanate. Specific examples include 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, and 4,4 ', 4 "-triphenylmethane triisocyanate.
- Examples of the isocyanate compound (B1) include multimers (for example, dimers or trimers, biurets, isocyanurates), derivatives (for example, many) of the above isocyanate compounds having 2 or 3 or more isocyanate groups. Addition reaction product of a dihydric alcohol and two or more molecules of a diisocyanate compound), and a polymer.
- polyhydric alcohol in the derivative examples include trivalent or higher alcohols such as trimethylolpropane, glycerin and pentaerythritol as low molecular weight polyhydric alcohols; high molecular weight polyhydric alcohols such as polyether polyols, Examples include polyester polyol, acrylic polyol, polybutadiene polyol, and polyisoprene polyol.
- isocyanate compounds include diphenylmethane diisocyanate trimer, polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate or tolylene diisocyanate biuret or isocyanurate, trimethylolpropane and tolylene diisocyanate or xylylene diisocyanate.
- Reaction product for example, a trimolecular adduct of tolylene diisocyanate or xylylene diisocyanate
- reaction product of trimethylolpropane and hexamethylene diisocyanate for example, a trimolecular adduct of hexamethylene diisocyanate
- polyether polyisocyanate for example, a polyether polyisocyanate
- Polyester polyisocyanate is mentioned.
- isocyanate compounds (B1) a reaction product of trimethylolpropane and tolylene diisocyanate or xylylene diisocyanate (L-45, Soken Chemical Co., Ltd.) TD-75 manufactured by KK), isocyanurate of hexamethylene diisocyanate or tolylene diisocyanate (TSE-100 manufactured by Asahi Kasei Kogyo Co., Ltd., 2050 manufactured by Nippon Polyurethane Co., Ltd.).
- An isocyanate compound (B1) may be used individually by 1 type, and may use 2 or more types.
- Metal chelate compound (B2) examples include polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium, alkoxide, acetylacetone, and ethyl acetoacetate. Examples include a coordinated compound. Among these, an aluminum chelate compound (M-12AT manufactured by Soken Chemical Co., Ltd.) is particularly preferable. Specific examples include aluminum isopropylate, aluminum secondary butyrate, aluminum ethyl acetoacetate / diisopropylate, aluminum trisethyl acetoacetate, and aluminum trisacetylacetonate.
- polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium, alkoxide, acetylacetone, and ethyl acetoacetate. Examples include a coordinated compound.
- a metal chelate compound (B2) may be used individually by 1 type, and may use 2 or more types.
- the total content of the (B1) and (B2) is the (meth) acrylic copolymer (A ) It is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 2.5 parts by mass, and still more preferably 0.1 to 1 part by mass with respect to 100 parts by mass.
- the loss tangent of the pressure-sensitive adhesive layer can be adjusted to the above range. When this content exceeds the above range, the loss tangent of the pressure-sensitive adhesive layer tends to be too small, and when the content is below the range, the loss tangent of the pressure-sensitive adhesive layer tends to become too large.
- the content of the metal chelate compound (B2) is preferably 10 to 1000 parts by weight, more preferably 50 to 600 parts by weight, more preferably 100 parts by weight of the isocyanate compound (B1).
- the amount is preferably 100 to 400 parts by mass.
- the loss tangent of the pressure-sensitive adhesive layer can be adjusted to the above range.
- the total amount of (B1) and (B2) is constant, if the content of (B2) exceeds the above range, the loss tangent of the pressure-sensitive adhesive layer tends to be too large. The loss tangent of the pressure-sensitive adhesive layer tends to be too small.
- Epoxy compound (B3) an epoxy compound having 2 or more epoxy groups in one molecule is usually used.
- the content of the (B3) is based on 100 parts by mass of the (meth) acrylic copolymer (A).
- the amount is preferably 0 to 2 parts by mass, more preferably 0 to 1 part by mass, and still more preferably 0 to 0.5 part by mass.
- the pressure-sensitive adhesive composition for polarizing plates of the present invention preferably further contains a silane coupling agent (C).
- a silane coupling agent (C) contributes to the point which adheres an adhesive layer firmly to adherends, such as a glass plate, and prevents peeling in a high-humidity heat environment.
- silane coupling agent (C) examples include polymerizable unsaturated group-containing silane coupling agents such as vinyltrimethoxysilane, vinyltriethoxysilane, and methacryloxypropyltrimethoxysilane; 3-glycidoxypropyltrimethoxysilane Epoxy groups such as 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane Containing silane coupling agent; amino such as 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane Group-containing silane coupling Grayed
- the content of the silane coupling agent (C) in the pressure-sensitive adhesive composition for polarizing plates of the present invention is usually 1 part by mass or less, preferably 0 with respect to 100 parts by mass of the (meth) acrylic copolymer (A). 0.01 to 1 part by mass, more preferably 0.05 to 0.5 part by mass. When the content is in the above range, peeling of the polarizing plate in a high humidity environment and bleeding of the silane coupling agent (C) in a high temperature environment tend to be prevented.
- An antistatic agent (D) can be used in order to reduce the surface resistance value of the adhesive composition for polarizing plates of this invention, for example.
- examples of the antistatic agent (D) include a surfactant, an ionic compound, and a conductive polymer.
- surfactant examples include cationic surfactants having cationic groups such as quaternary ammonium salts, amide quaternary ammonium salts, pyridium salts, primary to tertiary amino groups; sulfonate groups, sulfate esters Anionic surfactants having an anionic group such as a base or a phosphate ester base; amphoteric surfactants such as alkylbetaines, alkylimidazolinium betaines, alkylamine oxides, amino acid sulfates, glycerin fatty acid esters
- Nonionic surfactants such as sorbitan fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene alkylamine fatty acid esters, N-hydroxyethyl-N-2-hydroxyalkylamines and alkyldiethanolamides It is done.
- a reactive emulsifier having a polymerizable group is also exemplified as the surfactant, and a polymer surfactant obtained by increasing the molecular weight of the monomer component containing the above surfactant or reactive emulsifier can also be used.
- the ionic compound is composed of a cation part and an anion part, and may be either solid or liquid at room temperature (23 ° C./50% RH).
- the cation portion constituting the ionic compound may be either an inorganic cation or an organic cation, or both.
- the inorganic cation alkali metal ions and alkaline earth metal ions are preferable, and Li + , Na + and K + having excellent antistatic properties are more preferable.
- organic cation examples include pyridinium cation, piperidinium cation, pyrrolidinium cation, pyrroline cation, pyrrole cation, imidazolium cation, tetrahydropyrimidinium cation, dihydropyrimidinium cation, pyrazolium cation, and pyrazolinium.
- examples include cations, tetraalkylammonium cations, trialkylsulfonium cations, tetraalkylphosphonium cations, and derivatives thereof.
- the anion moiety constituting the ionic compound is not particularly limited as long as it can form an ionic compound by ionic bonding with the cation moiety.
- Examples of the ionic compound include lithium bis (trifluoromethanesulfonyl) imide, lithium bis (difluorosulfonyl) imide, lithium tris (trifluoromethanesulfonyl) methane, potassium bis (trifluoromethanesulfonyl) imide, potassium bis (difluorosulfonyl) imide, 1 -Ethylpyridinium hexafluorophosphate, 1-butylpyridinium hexafluorophosphate, 1-hexyl-4-methylpyridinium hexafluorophosphate, 1-octyl-4-methylpyridinium hexafluorophosphate, 1-octyl-4-methylpyridinium bis (fluoro Sulfonyl) imide, 1-octyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide, (N, N-die) -N
- the conductive polymer examples include polythiophene, polyaniline, polypyrrole, and derivatives thereof.
- the content of the antistatic agent (D) in the pressure-sensitive adhesive composition for polarizing plates of the present invention is usually 3 parts by mass or less, preferably 0.8 parts per 100 parts by mass of the (meth) acrylic copolymer (A). The amount is from 01 to 3 parts by mass, more preferably from 0.05 to 2.5 parts by mass.
- the pressure-sensitive adhesive composition of the present invention preferably contains an organic solvent (E) in order to adjust its coatability.
- an organic solvent the polymerization solvent demonstrated in the column of the (meth) acrylic-type copolymer (A) is mentioned.
- the pressure-sensitive adhesive composition can be prepared by mixing the polymer solution containing the (meth) acrylic copolymer (A) and the polymerization solvent obtained by the above copolymerization and the crosslinking agent (B). it can.
- the content of the organic solvent is usually 50 to 90% by mass, preferably 60 to 85% by mass.
- solid content refers to all components excluding the organic solvent (E) among the components contained in the pressure-sensitive adhesive composition
- solid content concentration refers to the pressure-sensitive adhesive composition 100. The ratio of the said solid content with respect to the mass% is said.
- the pressure-sensitive adhesive composition of the present invention does not contain a peroxide (peroxide-based crosslinking agent) as a crosslinking agent.
- the peroxide content including the remaining amount of the peroxide polymerization initiator used during the synthesis of the (meth) acrylic copolymer (A), is (meth) acrylic copolymer (A) 100.
- it is 0.1 mass part or less with respect to a mass part, More preferably, it is 0.05 mass part or less, More preferably, it is 0.01 mass part or less.
- An adhesive based on residual peroxide by using an isocyanate compound (B1), a metal chelate compound (B2), an epoxy crosslinking agent (B3), etc. as a crosslinking agent (B) and not using a peroxide-based crosslinking agent. The deterioration of the layer over time can be suppressed.
- the pressure-sensitive adhesive composition of the present invention includes an antioxidant, a light stabilizer, a metal corrosion inhibitor, a tackifier, a plasticizer, a crosslinking accelerator, You may contain the 1 type (s) or 2 or more types selected from the (meth) acrylic-type polymer and rework agents other than A).
- the pressure-sensitive adhesive composition for polarizing plates of the present invention is obtained by mixing a (meth) acrylic copolymer (A), a crosslinking agent (B), and other components as required by a conventionally known method. Can be prepared.
- the cross-linking agent (B) and, if necessary, other components may be added to the polymer solution containing the polymer obtained when the (meth) acrylic copolymer (A) is synthesized. It is done.
- the pressure-sensitive adhesive layer of the present invention specifically cross-links the (meth) acrylic copolymer (A) with the cross-linking agent (B) by, for example, advancing the crosslinking reaction in the above-mentioned pressure-sensitive adhesive composition. Is obtained.
- the pressure-sensitive adhesive layer of the present invention has a loss tangent (tan ⁇ 1 ) at 23 ° C. of 0.33 to 0.55, preferably 0.35 to 0.52, particularly preferably 0.40 to 0.49, and
- the loss tangent (tan ⁇ 2 ) at 80 ° C. is 0.40 to 0.65, preferably 0.42 to 0.62, and particularly preferably 0.47 to 0.56.
- the pressure-sensitive adhesive layer, 23 the ratio of the loss tangent (tan [delta 2) in the loss tangent (tan [delta 1) and 80 ° C. at °C (tan ⁇ 2 / tan ⁇ 1) is preferably 1.10 or more, more preferably 1.10 To 5.0, more preferably 1.10 to 2.0.
- the loss tangent is, for example, a value calculated from a dynamic viscoelastic spectrum measured for a laminate having a thickness of about 1.0 mm by laminating the adhesive layers a plurality of times.
- the conditions for forming the pressure-sensitive adhesive layer are, for example, as follows.
- the pressure-sensitive adhesive composition of the present invention is applied on a support and varies depending on the type of solvent, but is usually 50 to 150 ° C., preferably 60 to 100 ° C., usually 1 to 10 minutes, preferably 2 to 7 minutes. Then, the solvent is removed and a coating film is formed.
- the film thickness of the dried coating film is usually 5 to 75 ⁇ m, preferably 10 to 50 ⁇ m.
- the pressure-sensitive adhesive layer is preferably formed under the following conditions. After applying the pressure-sensitive adhesive composition of the present invention on a support and applying a cover film on the coating film formed under the above conditions, usually 3 days or more, preferably 7 to 10 days, usually 5 to 60 ° C., It is preferably cured in an environment of 15 to 40 ° C., usually 30 to 70% RH, preferably 40 to 70% RH. When crosslinking is performed under the aging conditions as described above, a crosslinked body (network polymer) can be efficiently formed.
- a predetermined thickness is obtained by a known method such as spin coating, knife coating, roll coating, bar coating, blade coating, die coating, or gravure coating.
- a method of applying and drying can be used.
- polyester films such as polyethylene terephthalate (PET); plastic films such as polyolefin films such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer.
- PET polyethylene terephthalate
- plastic films such as polyolefin films such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer.
- the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present invention has a gel fraction of preferably 10 to 70% by mass, more preferably from the viewpoint of distortion suppression of the polarizing plate, cohesive strength, adhesive strength, and removability. Is 15 to 65% by mass, more preferably 20 to 60% by mass. Even if the gel fraction is in the above range, the (meth) acrylic copolymer (A) has highly branched chains, so that the branched chains of the copolymer (A) may be appropriately entangled with each other. The durability and workability of the pressure-sensitive adhesive layer are not deteriorated. In particular, when the gel fraction is 20% by mass or more, a highly cohesive pressure-sensitive adhesive layer can be obtained. When the gel fraction exceeds the above range, the pressure-sensitive adhesive layer may not be able to sufficiently absorb or relax the stress caused by the dimensional change of the polarizing plate under a high temperature / high humidity heat environment.
- the pressure-sensitive adhesive sheet for polarizing plates of the present invention has a pressure-sensitive adhesive layer formed from the above-mentioned pressure-sensitive adhesive composition for polarizing plates.
- the pressure-sensitive adhesive sheet include a double-sided pressure-sensitive adhesive sheet having only the pressure-sensitive adhesive layer, a base material, and a double-sided pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer formed on both surfaces of the base material, the base material, and one of the base materials.
- Examples thereof include a single-sided pressure-sensitive adhesive sheet having the above-mentioned pressure-sensitive adhesive layer formed on the surface, and a pressure-sensitive adhesive sheet having a peel-treated cover film attached to the surface of the pressure-sensitive adhesive sheet that is not in contact with the base material.
- polyester films such as polyethylene terephthalate (PET); plastic films such as polyolefin films such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer.
- PET polyethylene terephthalate
- plastic films such as polyolefin films such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer.
- the conditions for forming the pressure-sensitive adhesive layer, the loss tangent, and the gel fraction are the same as the conditions described in the column “Pressure-sensitive adhesive layer for polarizing plate”.
- the thickness of the pressure-sensitive adhesive layer is usually 5 to 75 ⁇ m, preferably 10 to 50 ⁇ m, from the viewpoint of maintaining adhesive performance.
- the film thickness of the substrate and the cover film is not particularly limited, but is usually 10 to 125 ⁇ m, preferably 25 to 75 ⁇ m.
- the polarizing plate with a pressure-sensitive adhesive layer of the present invention comprises a polarizing plate and a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition for a polarizing plate of the present invention on at least one surface of the polarizing plate.
- polarizing plate is used to include “polarizing film”.
- a conventionally known polarizing film can be used as the polarizing plate.
- a multilayer film having a stretched film obtained by adding a polarizing component to a film made of a polyvinyl alcohol-based resin and stretching, and a protective film disposed on the stretched film can be mentioned.
- the polyvinyl alcohol-based resin include polyvinyl alcohol, polyvinyl formal, polyvinyl acetal, and a saponified product of an ethylene / vinyl acetate copolymer.
- the polarization component include iodine or a dichroic dye.
- the protective film include cellulose films such as triacetyl cellulose, polycarbonate films, and polyethersulfone films.
- the thickness of the polarizing plate is usually 30 to 250 ⁇ m, preferably 50 to 200 ⁇ m.
- the adhesive sheet for polarizing plates of this invention has A method of transferring the pressure-sensitive adhesive layer to the surface of the polarizing plate and aging is mentioned.
- the conditions for drying and aging, the loss tangent, the range of the gel fraction, and the like are the same as the conditions described in the section of [Adhesive layer for polarizing plate].
- the thickness of the pressure-sensitive adhesive layer formed on the polarizing plate is usually 5 to 75 ⁇ m, preferably 10 to 50 ⁇ m in terms of dry film thickness.
- the adhesive layer should just be formed in at least one surface of a polarizing plate, the aspect in which an adhesive layer is formed only in the single side
- the layer which has other functions such as a protective layer, a glare-proof layer, a phase difference layer, a viewing angle improvement layer, for example may be laminated
- a liquid crystal element is produced by providing the polarizing plate with the pressure-sensitive adhesive layer of the present invention obtained as described above on the substrate surface of the liquid crystal cell.
- the liquid crystal cell has a structure in which a liquid crystal layer is sandwiched between two substrates.
- the substrate of the liquid crystal cell examples include a glass plate.
- the thickness of the substrate is usually 0.1 to 1 mm, preferably 0.15 to 0.8 mm.
- substrate can be suppressed by using the said adhesive composition. Therefore, even when the thickness of the substrate is small (eg, 0.8 mm or less, preferably 0.15 to 0.7 mm), the above-mentioned pressure-sensitive adhesive composition is suitably used for bonding the polarizing plate and the substrate. be able to.
- GPC and GPC-MALS For the (meth) acrylic copolymer, the gel permeation chromatography method (GPC method) is used to determine the weight average molecular weight (Mw) and the number average molecular weight (Mn) under the following conditions. The degree of branching was determined using a laser light scattering detector (GPC-MALS) under the following conditions.
- HLC-8320GPC manufactured by Tosoh Corporation
- -GPC column configuration The following four columns (all manufactured by Tosoh Corporation) (1) TSKgel HxL-H (guard column) (2) TSKgel GMHxL (3) TSKgel GMHxL (4) TSKgel G2500HxL ⁇ Flow rate: 1.0 mL / min -Column temperature: 40 ° C Sample concentration: 1.5% (w / v) (diluted with tetrahydrofuran) ⁇ Mobile phase solvent: Tetrahydrofuran ⁇ Detector: DAWN HELEOS (MALS detector) + Optilab rEX (RI detector) ⁇ Standard polystyrene conversion (when measuring Mw and Mn)
- the obtained (meth) acrylic copolymer A had a weight average molecular weight (Mw) of 700,000, a molecular weight distribution (Mw / Mn) of 7.1, and an acid value of 1.6 mgKOH / g. .
- Example 1 (1) Preparation of pressure-sensitive adhesive composition (meth) acrylic polymer solution obtained in Synthesis Example 1 (solid content concentration: 30% by mass) and 100 parts (meth) acrylic polymer contained in the solution (solid content) In contrast, 0.05 part (solid content) of “TD-75” (solid content: 75 mass%, ethyl acetate solution) manufactured by Soken Chemical Co., Ltd. as the isocyanate compound, and “TD-75” manufactured by Soken Chemical Co., Ltd. as the metal chelate compound.
- M-12AT solid content 10% by mass, toluene, acetylacetone solution 0.14 parts (solid content) and“ KBM-403 ”(solid content 100%) 0 manufactured by Shin-Etsu Chemical Co., Ltd. as a silane coupling agent 2 parts and 1 part of “AS-804” (100% solid content) manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. as an antistatic agent were mixed to obtain an adhesive composition.
- the pressure-sensitive adhesive composition obtained in (1) above was applied onto a polyethylene terephthalate film (PET film) subjected to a release treatment using a doctor blade, It dried at 90 degreeC for 3 minute (s), and obtained the sheet
- the sheet and the polarizing plate (thickness: 110 ⁇ m, layer structure: triacetyl cellulose film / polyvinyl alcohol film / triacetyl cellulose film) were bonded together so that the coating film and the polarizing plate were in contact with each other, and 23 ° C./50%.
- the plate was allowed to stand and matured for 7 days under the conditions of RH to obtain a polarizing plate with a pressure-sensitive adhesive layer having a PET film, a pressure-sensitive adhesive layer having a thickness of 20 ⁇ m, and a polarizing plate.
- Example 1 is different from Example 1 except that the (meth) acrylic polymer solution is changed to the polymer solution obtained in Synthesis Examples 2 to 13 and / or the composition is changed as shown in Table 2. Similarly, a pressure-sensitive adhesive composition, a pressure-sensitive adhesive sheet, and a polarizing plate with a pressure-sensitive adhesive layer were obtained.
- the polarizing plate with a pressure-sensitive adhesive layer obtained in Examples and Comparative Examples was cut into a width of 10 mm and a length of 100 mm, and the peeled PET film was peeled off. And it bonded together so that the said adhesive layer might contact the said glass plate and it might become a bonding area of 10 mm x 10 mm on the alkali treatment glass plate, and the adhesion processing polarizing plate test piece for evaluation was obtained.
- the autoclaving process (50 degreeC, 5 atm) was performed about the adhesive-processed polarizing plate test piece for evaluation, and it left still for 24 hours in 23 degreeC / 50% RH atmosphere.
- the test piece was set in a chamber BOX of a minute creep measuring machine with a fixing chuck portion having a length of 15 mm.
- the evaluation-treated pressure-sensitive adhesive polarizing plate in the test piece was pulled in parallel with the adhesive surface between the polarizing plate and the glass plate and in the length direction of the polarizing plate, The distance ( ⁇ m) of the gap between the glass plate and the polarizing plate in the test piece was measured as the creep value.
- a polarizing plate with a pressure-sensitive adhesive layer obtained in Examples and Comparative Examples (a laminate comprising PET film / pressure-sensitive adhesive layer / polarizing plate) was cut into a size of 70 mm ⁇ 25 mm to prepare a test piece.
- the PET film was peeled from the test piece, and a laminate composed of the pressure-sensitive adhesive layer / polarizing plate was attached to one side of a 2 mm thick glass plate so that the pressure-sensitive adhesive layer and the glass plate were in contact with each other using a laminator roll. .
- the obtained laminate was held in an autoclave adjusted to 50 ° C./5 atm for 20 minutes.
- the end of the polarizing plate was pulled at a rate of 300 mm / min in the 90 ° direction with respect to the glass plate surface, and the adhesive strength (peel strength) was measured.
- a test piece was prepared by cutting the polarizing plate with the pressure-sensitive adhesive layer (PET film / pressure-sensitive adhesive layer / laminate comprising the polarizing plate) obtained in Examples and Comparative Examples into a size of 35 mm ⁇ 400 mm (stretching axis direction). did.
- the PET film is peeled off from the test piece, and the laminate composed of the pressure-sensitive adhesive layer / polarizing plate is laminated on one side of a glass plate having a thickness of 0.7 mm and 40 mm ⁇ 410 mm using a laminator roll. Affixed to touch.
- the obtained laminate was allowed to stand in a 23 ° C./50% RH environment for 24 hours, and then held in an oven at 60 ° C. for 72 hours. One end was fixed to a wall surface perpendicular to the floor surface, and the amount of lifting at the opposite end was measured with a ruler. Measurements were taken immediately after removal from the oven and after 24 hours.
- a polarizing plate with a pressure-sensitive adhesive layer obtained in Examples and Comparative Examples (a laminate comprising PET film / pressure-sensitive adhesive layer / polarizing plate) was cut into a size of 150 mm ⁇ 250 mm to prepare a test piece.
- the PET film was peeled from the test piece, and a laminate composed of the pressure-sensitive adhesive layer / polarizing plate was attached to one side of a 2 mm thick glass plate so that the pressure-sensitive adhesive layer and the glass plate were in contact with each other using a laminator roll. .
- the obtained laminate was held in an autoclave adjusted to 50 ° C./5 atm for 20 minutes to prepare a test plate. Two similar test plates were prepared.
- test plate is allowed to stand for 500 hours under conditions of a temperature of 80 ° C. (heat resistance) or a temperature of 60 ° C./humidity of 90% RH (humid heat resistance), and the occurrence of foaming and tearing is observed according to the following criteria. evaluated. Foaming occurs when cohesion is insufficient, and tearing occurs when stress relaxation is insufficient.
- (Foam) -AA Foaming is not seen at all.
- -BB The area of foaming is less than 1% of the whole.
- -CC The area of foaming is 1% or more and less than 5% of the whole.
- -DD The area of foaming is 5% or more of the whole.
- (Rupture) -AA No tear is seen at all.
- -BB The area of a tear is less than 1% of the whole.
- -CC The area of a fracture is 1% or more and less than 5% of the whole.
- DD The area of the tear is 5% or more of the whole.
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Abstract
Description
[1](A)アルキル基の炭素数が4~18の(メタ)アクリル酸アルキルエステルおよび極性基含有モノマーを含むモノマー成分を共重合して得られる(メタ)アクリル系共重合体と、(B)架橋剤とを含有する偏光板用粘着剤組成物であり、前記組成物より形成された粘着剤層の、23℃における損失正接(tanδ1)が0.33~0.55であり、かつ80℃における損失正接(tanδ2)が0.40~0.65であることを特徴とする偏光板用粘着剤組成物。
本発明の偏光板用粘着剤組成物は、(メタ)アクリル系共重合体(A)と架橋剤(B)とを含有する組成物であり、前記粘着剤組成物より形成された粘着剤層の、23℃における損失正接(tanδ1)が0.33~0.55であり、かつ80℃における損失正接(tanδ2)が0.40~0.65であることを特徴とする。
ここで、本発明の粘着剤組成物の特性として、以下の条件で形成した厚さ1.0mmの粘着剤層について、Anton Paar製「Physica MCR300」を用いて、JIS K7244に準拠した動的粘弾性測定法(温度範囲-40~180℃、昇温速度3.67℃/分、周波数1Hzの条件)により粘弾性スペクトルを測定することにより、損失正接を得ることができる。
(メタ)アクリル系共重合体(A)は、アルキル基の炭素数が4~18の(メタ)アクリル酸アルキルエステルおよび極性基含有モノマーを含むモノマー成分を共重合して得られた共重合体である。共重合体(A)のモノマー成分としては、これら以外のその他のモノマーが挙げられる。
(メタ)アクリル酸アルキルエステルとしては、アルキル基の炭素数が4~18の(メタ)アクリル酸アルキルエステル(CH2=CR1-COOR2;R1は水素原子またはメチル基であり、R2は炭素数4~18のアルキル基である)が用いられ、ここで前記アルキル基の炭素数は4~12がより好ましい。
極性基含有モノマーとしては、例えば、水酸基含有モノマー、酸基含有モノマー、アミノ基含有モノマー、アミド基含有モノマー、窒素系複素環含有モノマー、シアノ基含有モノマーが挙げられる。本明細書において酸基としては、例えば、カルボキシル基、酸無水物基、リン酸基、硫酸基が挙げられる。極性基含有モノマーとしては、架橋剤(B)が有する架橋性官能基と反応することが可能な極性基(架橋性官能基)を有するモノマーを用いることが好ましい。
水酸基含有モノマーに含まれる当該水酸基は、例えばイソシアネート化合物(B1)に含まれるイソシアネート基との架橋性官能基として機能する。水酸基含有モノマーの使用量は、モノマー成分100質量%中、好ましくは0~15質量%、より好ましくは0.05~10質量%、さらに好ましくは0.1~7質量%である。水酸基含有モノマーの使用量が前記上限値以下であると、(メタ)アクリル系共重合体(A)とイソシアネート化合物(B1)とにより形成される架橋密度が高くなりすぎず、応力緩和特性に優れる粘着剤層が得られる。水酸基含有モノマーの使用量が前記下限値以上であると、架橋構造が有効に形成され、常温において適切な強度を有する粘着剤層が得られる。
極性基含有モノマーは1種単独で用いてもよく、2種以上を用いてもよい。
(メタ)アクリル系共重合体(A)を形成するモノマー成分は、(メタ)アクリル系共重合体(A)の物性を損なわない範囲で、例えば、アルコキシアルキル(メタ)アクリレート、アルコキシポリアルキレングリコールモノ(メタ)アクリレート、脂環式基または芳香環含有(メタ)アクリレートなどの、その他の(メタ)アクリル酸エステルを含むことができる。
その他のモノマーは1種単独で用いてもよく、2種以上を用いてもよい。
(メタ)アクリル系共重合体(A)は、過酸化物系重合開始剤の存在下で前記共重合により得られた共重合体であることが好ましい。重合開始剤として、過酸化物系重合開始剤を用いることで、分岐の多いポリマー分子が得られる傾向にある。このため、(1)室温程度ではポリマー分子相互の分岐鎖に起因する絡み合いが多く発生し、結果として、ポリマーの分子量および粘着剤層のゲル分率が低い設計においても、ポリマーの凝集性が維持され、粘着特性、粘着剤層を打ち抜く等の加工性、粘着剤層の変形およびはみ出しが少ない等の保管性に優れる粘着剤層が得られ;(2)高温(例:60℃)ではポリマー分子相互の前記絡み合いが一部緩むため、粘着剤層の粘性的性質増加度の温度依存性が高く、粘着剤層が優れた柔軟性を示す。そのため、偏光板の反り(ベンディング)抑制に優れるとともに、一部残存している前記絡み合いに起因して、粘着剤層が優れた耐久性を示す。
ジ(2-tert-ブチルパーオキシイソプロピル)ベンゼン、ジクミルパーオキサイド、2,5-ジメチル-2,5-ジ(tert-ブチルパーオキシ)ヘキサン、tert-ブチルクミルパーオキサイド、ジ-tert-ヘキシルパーオキサイド、ジ-tert-ブチルパーオキサイド等のジアルキルパーオキサイド類(例:R-O-O-Rで表される化合物、式中のRはそれぞれ独立にアルキル基またはアリール基置換アルキル基である;R-O-O-A-O-O-Rで表される化合物、式中のRはそれぞれ独立にアルキル基またはアリール基置換アルキル基であり、Aは2価の炭化水素基である);
ジイソブチリルパーオキサイド、ジ(3,5,5-トリメチルヘキサノイル)パーオキサイド、ジラウロイルパーオキサイド、ジベンゾイルパーオキサイド、ベンゾイル(3-メチルベンゾイル)パーオキサイド、ジ(3-メチルベンゾイル)パーオキサイド、ジ(4-メチルベンゾイル)パーオキサイド等のジアシルパーオキサイド類(例:R-COO-OCO-Rで表される化合物、式中のRはそれぞれ独立にアルキル基またはアリール基である);
ジ-n-プロピルパーオキシジカーボネート、ジイソプロピルパーオキシジカーボネート、ジ(4-tert-ブチルシクロヘキシル)パーオキシジカーボネート、ジ(2-エチルヘキシル)パーオキシジカーボネート、ジ-sec-ブチルパーオキシジカーボネート等のパーオキシジカーボネート(例:R-OCO-O-O-COO-Rで表される化合物、式中のRはそれぞれ独立にアルキル基またはシクロアルキル基である);
クミルパーオキシネオデカノエート、1,1,3,3-テトラメチルブチルパーオキシネオデカノエート、tert-ヘキシルパーオキシネオデカノエート、tert-ブチルパーオキシネオデカノエート、tert-ブチルパーオキシネオヘプタノエート、tert-ヘキシルパーオキシピバレート、tert-ブチルパーオキシピバレート、1,1,3,3-テトラメチルブチルパーオキシ-2-エチルヘキサノエート、2,5-ジメチル-2,5-ジ(2-エチルヘキサノイルパーオキシ)ヘキサン、tert-ヘキシルパーオキシ-2-エチルヘキサノエート、tert-ブチルパーオキシ-2-エチルヘキサノエート、tert-ブチルパーオキシ-3,5,5-トリメチルヘキサノエート、tert-ブチルパーオキシラウレート、tert-ヘキシルパーオキシベンゾエート、2,5-ジメチル-2,5-ジ(ベンゾイルパーオキシ)ヘキサン、tert-ブチルパーオキシアセテート、tert-ブチルパーオキシ-3-メチルベンゾエート、tert-ブチルパーオキシベンゾエート等のパーオキシエステル類(例:R1-O-O-CO-R2で表される化合物、式中のR1はアルキル基またはアリール基置換アルキル基であり、R2はアルキル基、アリール基またはアリール基置換アルキル基である;R-CO-O-O-A-O-O-CO-Rで表される化合物、式中のRはそれぞれ独立にアルキル基またはアリール基であり、Aは2価の炭化水素基である);
tert-ヘキシルパーオキシイソプロピルモノカーボネート、tert-ブチルパーオキシイソプロピルモノカーボネート、tert-ブチルパーオキシ-2-エチルヘキシルモノカーボネート等のパーオキシモノカーボネート類(例:R-O-O-COO-Rで表される化合物、式中のRはそれぞれ独立にアルキル基である);
が挙げられる。
重合開始剤として、高分岐鎖の共重合体が得られる限り、過酸化物系開始剤とともにアゾ系開始剤を用いることもできる。アゾ系開始剤としては、例えば、2,2'-アゾビスイソブチロニトリル、2,2'-アゾビス(4-メトキシ-2,4-ジメチルバレロニトリル)、2,2'-アゾビス(2-シクロプロピルプロピオニトリル)、2,2'-アゾビス(2,4-ジメチルバレロニトリル)、2,2'-アゾビス(2-メチルブチロニトリル)、1,1'-アゾビス(シクロヘキサン-1-カルボニトリル)、2-(カルバモイルアゾ)イソブチロニトリル、2-フェニルアゾ-4-メトキシ-2,4-ジメチルバレロニトリル、2,2'-アゾビス(2-アミジノプロパン)ジヒドロクロリド、2,2'-アゾビス(N,N'-ジメチレンイソブチルアミジン)、2,2'-アゾビス〔2-メチル-N-(2-ヒドロキシエチル)-プロピオンアミド〕、2,2'-アゾビス(イソブチルアミド)ジヒドレート、4,4'-アゾビス(4-シアノペンタン酸)、2,2'-アゾビス(2-シアノプロパノール)、ジメチル-2,2'-アゾビス(2-メチルプロピオネート)、2,2'-アゾビス[2-メチル-N-(2-ヒドロキシエチル)プロピオンアミド]等のアゾ化合物が挙げられる。これらの重合開始剤は1種単独で用いてもよく、2種以上を用いてもよい。
残存率(%)=exp(-kdt)×100(%)
式中、kdは熱分解速度定数であり、アレニウスの式:kd=A×exp(-ΔE/RT)で表され、ここでAは頻度因子であり、ΔEは重合開始剤の熱分解反応における活性化エネルギーであり、Rは気体定数(8.314J/mol・K)であり、Tは絶対温度(K)であり;tは反応時間である。
(メタ)アクリル系共重合体(A)は、ゲルパーミエーションクロマトグラフィー法(GPC法)により測定される重量平均分子量(Mw)が、ポリスチレン換算値で、通常20万~150万であり、好ましくは40万~130万、より好ましくは50万~110万である。例えば、Mwが小さい共重合体(A)を用いると、架橋後のポリマーの分子量が比較的小さく抑えられることから、高温での粘着剤の流動性が上がり、損失正接が大きくなる傾向にある。一方、Mwが大きい共重合体(A)を用いると、架橋後のポリマーの分子量が高くなり、高温での粘着剤の流動性が下がり、損失正接が小さくなる傾向にある。
(メタ)アクリル系共重合体(A)は、GPC-MALS法により測定される分岐度が、0.55以下であることが好ましく、より好ましくは0.10~0.54、さらに好ましくは0.20~0.53、特に好ましくは0.30~0.53である。分岐度の測定条件の詳細は、実施例に記載する。粘着剤層の損失正接を上記範囲に調整するためには、分岐度が前記範囲にある共重合体(A)を用いることが好ましい。
Foxの式:1/Tg=(W1/Tg1)+(W2/Tg2)+…+(Wm/Tgm)
W1+W2+…+Wm=1
式中、Tgは(メタ)アクリル系共重合体(A)のガラス転移温度であり、Tg1,Tg2,…,Tgmは各モノマーからなるホモポリマーのガラス転移温度であり、W1,W2,…,Wmは各モノマー由来の構成単位の前記共重合体(A)における重量分率である。
架橋剤(B)は、(メタ)アクリル系共重合体(A)と架橋反応を起こすことができる成分であれば特に限定されないが、例えば、イソシアネート化合物(B1)、金属キレート化合物(B2)、エポキシ化合物(B3)が挙げられる。
架橋剤(B)の中でも、イソシアネート化合物(B1)および金属キレート化合物(B2)を組み合わせて用いることが好ましい。粘着剤層の損失正接を上記範囲に調整する観点から、(メタ)アクリル系共重合体(A)に対して、イソシアネート化合物(B1)に基づく共有結合による架橋と、金属キレート化合物(B2)に基づく配位結合による疑似架橋とを形成することが好ましい。
イソシアネート化合物(B1)としては、1分子中のイソシアネート基数が2以上のイソシアネート化合物が通常用いられる。イソシアネート化合物(B1)により(メタ)アクリル系共重合体(A)を架橋することで、架橋体(ネットワークポリマー)を形成することができる。
イソシアネート化合物(B1)は1種単独で用いてもよく、2種以上を用いてもよい。
金属キレート化合物(B2)としては、例えば、アルミニウム、鉄、銅、亜鉛、スズ、チタン、ニッケル、アンチモン、マグネシウム、バナジウム、クロム、ジルコニウム等の多価金属に、アルコキシド、アセチルアセトン、アセト酢酸エチル等が配位した化合物が挙げられる。これらの中でも、特にアルミキレート化合物(綜研化学社製M-12AT等)が好ましい。具体的には、アルミニウムイソプロピレート、アルミニウムセカンダリーブチレート、アルミニウムエチルアセトアセテート・ジイソプロピレート、アルミニウムトリスエチルアセトアセテート、アルミニウムトリスアセチルアセトネートが挙げられる。
本発明の粘着剤組成物において、イソシアネート化合物(B1)と金属キレート化合物(B2)とを用いる場合、前記(B1)および(B2)の合計含有量は、(メタ)アクリル系共重合体(A)100質量部に対して、好ましくは0.01~5質量部、より好ましくは0.05~2.5質量部、さらに好ましくは0.1~1質量部である。この含有量が前記範囲にあると、粘着剤層の損失正接を上記範囲に調整することができる点で好ましい。この含有量が前記範囲を上回ると、粘着剤層の損失正接が小さくなり過ぎる傾向にあり、前記範囲を下回ると、粘着剤層の損失正接が大きくなり過ぎる傾向にある。
エポキシ化合物(B3)としては、1分子中のエポキシ基数が2以上のエポキシ化合物が通常用いられる。例えば、エチレングリコールジグリシジルエーテル、ポリエチレングリコールジグリシジルエーテル、グリセリンジグリシジルエーテル、グリセリントリグリシジルエーテル、1,3-ビス(N,N-ジグリシジルアミノメチル)シクロヘキサン、N,N,N',N'-テトラグリシジル-m-キシリレンジアミン、N,N,N',N'-テトラグリシジルアミノフェニルメタン、トリグリシジルイソシアヌレート、m-N,N-ジグリシジルアミノフェニルグリシジルエーテル、N,N-ジグリシジルトルイジン、N,N-ジグリシジルアニリンが挙げられる。
本発明の偏光板用粘着剤組成物は、さらにシランカップリング剤(C)を含有することが好ましい。シランカップリング剤(C)は、粘着剤層をガラス板等の被着体に対して強固に接着させ、高湿熱環境下で剥がれを防止する点に寄与する。
帯電防止剤(D)は、例えば、本発明の偏光板用粘着剤組成物の表面抵抗値を低下させるために使用することができる。帯電防止剤(D)としては、例えば、界面活性剤、イオン性化合物、導電性ポリマーが挙げられる。
イオン性化合物を構成するカチオン部としては、無機系カチオンまたは有機系カチオンのいずれか一方であっても双方であってもよい。無機系カチオンとしては、アルカリ金属イオンおよびアルカリ土類金属イオンが好ましく、帯電防止性が優れたLi+、Na+およびK+がより好ましい。有機系カチオンとしては、例えば、ピリジニウムカチオン、ピペリジニウムカチオン、ピロリジニウム系カチオン、ピロリンカチオン、ピロールカチオン、イミダゾリウムカチオン、テトラヒドロピリミジニウムカチオン、ジヒドロピリミジニウムカチオン、ピラゾリウムカチオン、ピラゾリニウムカチオン、テトラアルキルアンモニウムカチオン、トリアルキルスルホニウムカチオン、テトラアルキルホスホニウムカチオンおよびこれらの誘導体が挙げられる。
本発明の偏光板用粘着剤組成物における帯電防止剤(D)の含有量は、(メタ)アクリル系共重合体(A)100質量部に対して、通常3質量部以下、好ましくは0.01~3質量部、より好ましくは0.05~2.5質量部である。
本発明の粘着剤組成物は、その塗布性を調製するため、有機溶媒(E)を含有することが好ましい。有機溶媒としては、(メタ)アクリル系共重合体(A)の欄で説明した重合溶媒が挙げられる。例えば、上記共重合で得られた、(メタ)アクリル系共重合体(A)および重合溶媒を含むポリマー溶液と、架橋剤(B)とを混合して、粘着剤組成物を調製することができる。本発明の粘着剤組成物において、有機溶媒の含有量は、通常50~90質量%、好ましくは60~85質量%である。
本発明の粘着剤組成物には、架橋剤としての過酸化物(過酸化物系架橋剤)を配合しないことが好ましい。(メタ)アクリル系共重合体(A)の合成時に使用した過酸化物系重合開始剤の残存量も含めて、過酸化物の含有量は、(メタ)アクリル系共重合体(A)100質量部に対して、好ましくは0.1質量部以下であり、より好ましくは0.05質量部以下、さらに好ましくは0.01質量部以下である。架橋剤(B)としてイソシアネート化合物(B1)、金属キレート化合物(B2)、エポキシ架橋剤(B3)等を用い、過酸化物系架橋剤を用いないことで、残留した過酸化物に基づく粘着剤層の経時劣化を抑制することができる。
本発明の粘着剤組成物は、上記成分のほか、本発明の効果を損なわない範囲で、酸化防止剤、光安定剤、金属腐蝕防止剤、粘着付与剤、可塑剤、架橋促進剤、前記(A)以外の(メタ)アクリル系重合体およびリワーク剤から選択される1種または2種以上を含有してもよい。
本発明の偏光板用粘着剤組成物は、(メタ)アクリル系共重合体(A)と架橋剤(B)と、必要に応じて他の成分とを、従来公知の方法により混合することで調製することができる。例えば、(メタ)アクリル系共重合体(A)を合成する際に得られた、当該ポリマーを含むポリマー溶液に、架橋剤(B)と必要に応じて他の成分とを配合することが挙げられる。
本発明の粘着剤層は、例えば、上述の粘着剤組成物中の架橋反応を進めることにより、具体的には(メタ)アクリル系共重合体(A)を架橋剤(B)で架橋することにより得られる。
本発明の偏光板用粘着シートは、上述の偏光板用粘着剤組成物より形成された粘着剤層を有する。粘着シートとしては、例えば、上記粘着剤層のみを有する両面粘着シート、基材と、基材の両面に形成された上記粘着剤層とを有する両面粘着シート、基材と、基材の一方の面に形成された上記粘着剤層を有する片面粘着シート、およびそれら粘着シートの粘着剤層の基材と接していない面に剥離処理されたカバーフィルムが貼付された粘着シートが挙げられる。
粘着剤層の膜厚は、粘着性能維持の観点から、通常5~75μm、好ましくは10~50μmである。基材およびカバーフィルムの膜厚は、特に限定されないが、通常10~125μm、好ましくは25~75μmである。
本発明の粘着剤層付き偏光板は、偏光板と、前記偏光板の少なくとも一方の面に、本発明の偏光板用粘着剤組成物より形成された粘着剤層とを有することを特徴とする。なお、本明細書では、「偏光板」は「偏光フィルム」を包含する意味で用いる。
偏光板表面に粘着剤層を形成する方法に特に制限はなく、偏光板表面に直接バーコーター等を用いて上記粘着剤組成物を塗布し乾燥させる方法、本発明の偏光板用粘着シートが有する粘着剤層を偏光板表面に転写し熟成させる方法が挙げられる。乾燥および熟成の条件や損失正接、ゲル分率の範囲等は、〔偏光板用粘着剤層〕の欄に記載した条件と同様である。
上記のようにして得られる本発明の粘着剤層付き偏光板を液晶セルの基板表面に設けることにより液晶素子が製造される。ここで液晶セルは、液晶層が2枚の基板間に挟まれた構造を有している。
(メタ)アクリル系共重合体について、ゲルパーミエーションクロマトグラフィー法(GPC法)により、下記条件で、重量平均分子量(Mw)および数平均分子量(Mn)を、ゲルパーミエーションクロマトグラフィー法/多角度レーザー光散乱検出器(GPC-MALS)により、下記条件で、分岐度を求めた。
・測定装置:HLC-8320GPC(東ソー(株)製)
・GPCカラム構成:以下の4連カラム(すべて東ソー(株)製)
(1)TSKgel HxL-H(ガードカラム)
(2)TSKgel GMHxL
(3)TSKgel GMHxL
(4)TSKgel G2500HxL
・流速:1.0mL/min
・カラム温度:40℃
・サンプル濃度:1.5%(w/v)(テトラヒドロフランで希釈)
・移動相溶媒:テトラヒドロフラン
・検出器:DAWN HELEOS(MALS検出器)+Optilab rEX(RI検出器)
・標準ポリスチレン換算(MwおよびMnを測定する場合)
撹拌機、還流冷却器、温度計および窒素導入管を備えた反応装置に、n-ブチルアクリレート98.8部、4-ヒドロキシブチルアクリレート1部、アクリル酸0.2部、および酢酸エチル溶媒100部を仕込み、窒素ガスを導入しながら80℃に昇温した。次いで、tert-ブチルパーオキシピバレート0.1部を加え、窒素ガス雰囲気下、80℃で6時間重合反応を行った。反応終了後、酢酸エチルにて希釈し、固形分濃度30質量%のポリマー溶液を調製した。得られた(メタ)アクリル系共重合体Aの重量平均分子量(Mw)は70万であり、分子量分布(Mw/Mn)は7.1であり、酸価は1.6mgKOH/gであった。
重合反応に用いたモノマー成分および重合開始剤を表1に記載したとおりに変更したこと以外は合成例1と同様に行い、固形分濃度30質量%のポリマー溶液を調製した。結果を表1に示す。
(1)粘着剤組成物の調製
合成例1で得られた(メタ)アクリル系ポリマー溶液(固形分濃度30質量%)と、当該溶液に含まれる(メタ)アクリル系ポリマー100部(固形分量)に対して、イソシアネート化合物として綜研化学(株)製「TD-75」(固形分75質量%、酢酸エチル溶液)0.05部(固形分量)と、金属キレート化合物として綜研化学(株)製「M-12AT」(固形分10質量%、トルエン、アセチルアセトン溶液)0.14部(固形分量)と、シランカップリング剤として信越化学工業(株)製「KBM-403」(固形分100%)0.2部と、帯電防止剤として第一工業製薬(株)製「AS-804」(固形分100%)1部とを混合して、粘着剤組成物を得た。
泡抜け後、剥離処理されたポリエチレンテレフタレートフィルム(PETフィルム)上に、上記(1)で得られた粘着剤組成物をドクターブレードを用いて塗布し、90℃で3分間乾燥して、乾燥膜厚20μmの塗膜を形成した。塗膜の前記PETフィルムの貼付面とは反対面に、剥離処理されたPETフィルムをさらに貼り合わせ、23℃/50%RH環境下で7日間静置して熟成させて、2枚のPETフィルムに挟まれた厚さ20μmの粘着剤層を有する粘着シートを得た。
泡抜け後、剥離処理されたポリエチレンテレフタレートフィルム(PETフィルム)上に、上記(1)で得られた粘着剤組成物をドクターブレードを用いて塗布し、90℃で3分間乾燥して、乾燥膜厚20μmの塗膜を有するシートを得た。前記シートと偏光板(厚さ:110μm、層構成:トリアセチルセルロースフィルム/ポリビニルアルコールフィルム/トリアセチルセルロースフィルム)とを、前記塗膜と偏光板とが接するように貼り合わせ、23℃/50%RHの条件で7日間静置して熟成させて、PETフィルムと厚さ20μmの粘着剤層と偏光板とを有する粘着剤層付き偏光板を得た。
実施例1において、(メタ)アクリル系ポリマー溶液を合成例2~13で得られたポリマー溶液に変更し、および/または配合組成を表2に記載したとおりに変更したこと以外は実施例1と同様にして、粘着剤組成物、粘着シートおよび粘着剤層付き偏光板を得た。
〔損失正接〕
実施例・比較例で得られた粘着シートにおいて、厚さ20μmの粘着剤層同士を23℃/50%RH環境下で複数回貼り合わせ、50℃/5atmのオートクレーブで20分間処理して、厚さ1.0mmの粘着剤層を作製した。この厚さ1.0mmの粘着剤層について、Anton Paar製「Physica MCR300」を用いて、JIS K7244に準拠した動的粘弾性測定法(温度範囲-40~180℃、昇温速度3.67℃/分、周波数1Hzの条件)により粘弾性スペクトルを測定し、温度23℃および80℃における損失正接(tanδ)を決定した。
実施例・比較例で得られた粘着シートから、粘着剤約0.1gをサンプリング瓶に採取し、酢酸エチル30mLを加えて4時間振盪した後、このサンプル瓶の内容物を200メッシュのステンレス製金網で濾過し、金網上の残留物を100℃で2時間乾燥して乾燥重量を測定した。次式により、粘着剤のゲル分率を求めた。
・ゲル分率(%)=(乾燥重量/粘着剤採取重量)×100(%)
実施例・比較例で得られた粘着剤層付き偏光板(PETフィルム/粘着剤層/偏光板からなる積層体)を幅10mm×長さ100mmにカットし、前記剥離処理されたPETフィルムを剥がして、アルカリ処理ガラス板上に、前記粘着剤層が前記ガラス板に接するように、かつ10mm×10mmの貼り合わせ面積になるように貼り合わせて、評価用粘着加工偏光板試験片を得た。
実施例・比較例で得られた粘着剤層付き偏光板(PETフィルム/粘着剤層/偏光板からなる積層体)を70mm×25mmの大きさに裁断して試験片を作成した。試験片からPETフィルムを剥離し、ラミネーターロールを用いて、粘着剤層/偏光板からなる積層体を厚さ2mmのガラス板の片面に、粘着剤層とガラス板とが接するように貼着した。得られた積層体を、50℃/5気圧に調整されたオートクレーブ中に20分間保持した。次いで23℃/50%RH環境下に1時間放置した後、ガラス板面に対して90°方向に300mm/minの速度で偏光板端部を引っ張り、粘着力(剥離強度)を測定した。
実施例・比較例で得られた粘着剤層付き偏光板(PETフィルム/粘着剤層/偏光板からなる積層体)を35mm×400mm(延伸軸方向)の大きさに裁断して試験片を作成した。試験片からPETフィルムを剥離し、ラミネーターロールを用いて、粘着剤層/偏光板からなる積層体を厚さ0.7mm、40mm×410mmのガラス板の片面に、粘着剤層とガラス板とが接するように貼着した。得られた積層体を、23℃/50%RH環境下に24時間放置した後、60℃のオーブン中に72時間保持した。片方の末端を床面に対して垂直な壁面に固定し、逆側末端の浮き上がり量を定規で測定した。オーブンから取り出し直後、および24時間後に測定を実施した。
実施例・比較例で得られた粘着剤層付き偏光板(PETフィルム/粘着剤層/偏光板からなる積層体)を150mm×250mmの大きさに裁断して試験片を作成した。試験片からPETフィルムを剥離し、ラミネーターロールを用いて、粘着剤層/偏光板からなる積層体を厚さ2mmのガラス板の片面に、粘着剤層とガラス板とが接するように貼着した。得られた積層体を、50℃/5気圧に調整されたオートクレーブ中に20分間保持して、試験板を作成した。同様の試験板を2枚作成した。前記試験板を、温度80℃の条件下(耐熱性)または温度60℃/湿度90%RHの条件下(耐湿熱性)で500時間放置し、以下の基準で発泡および断裂の発生を観察して評価した。発泡は凝集力不足の場合に発生し、断裂は応力緩和不足の場合に発生する。
・AA:発泡が全く見られない。
・BB:発泡の面積が全体の1%未満である。
・CC:発泡の面積が全体の1%以上5%未満である。
・DD:発泡の面積が全体の5%以上である。
・AA:断裂が全く見られない。
・BB:断裂の面積が全体の1%未満である。
・CC:断裂の面積が全体の1%以上5%未満である。
・DD:断裂の面積が全体の5%以上である。
Claims (12)
- (A)アルキル基の炭素数が4~18の(メタ)アクリル酸アルキルエステルおよび極性基含有モノマーを含むモノマー成分を共重合して得られる(メタ)アクリル系共重合体と、
(B)架橋剤と
を含有する偏光板用粘着剤組成物であり、
前記組成物より形成された粘着剤層の、
23℃における損失正接(tanδ1)が0.33~0.55であり、かつ
80℃における損失正接(tanδ2)が0.40~0.65である
ことを特徴とする偏光板用粘着剤組成物。 - 架橋剤(B)が、イソシアネート化合物(B1)と、金属キレート化合物(B2)とを含む、請求項1記載の偏光板用粘着剤組成物。
- イソシアネート化合物(B1)100質量部に対する金属キレート化合物(B2)の含有量が、10~1000質量部である、請求項2記載の偏光板用粘着剤組成物。
- 前記極性基含有モノマーの極性基が、カルボキシル基および/または水酸基である、請求項1~3のいずれか1項記載の偏光板用粘着剤組成物。
- 前記(メタ)アクリル系共重合体(A)が、過酸化物系重合開始剤の存在下で前記共重合により得られた共重合体である、請求項1~4のいずれか1項記載の偏光板用粘着剤組成物。
- 前記(メタ)アクリル系共重合体(A)のゲルパーミエーションクロマトグラフィー法(GPC法)により測定される重量平均分子量(Mw)が、20万~150万である、請求項1~5のいずれか1項記載の偏光板用粘着剤組成物。
- 過酸化物の含有量が、(メタ)アクリル系共重合体(A)100質量部に対して、0.1質量部以下である、請求項1~6のいずれか1項記載の偏光板用粘着剤組成物。
- 前記偏光板用粘着剤組成物より形成された粘着剤のゲル分率が、10~70質量%である、請求項1~7のいずれか1項記載の偏光板用粘着剤組成物。
- 請求項1~8のいずれか1項記載の偏光板用粘着剤組成物より形成され、
23℃における損失正接(tanδ1)が0.33~0.55であり、かつ
80℃における損失正接(tanδ2)が0.40~0.65である
ことを特徴とする偏光板用粘着剤層。 - ゲル分率が、10~70質量%である、請求項9記載の偏光板用粘着剤層。
- 請求項9または10記載の偏光板用粘着剤層を有することを特徴とする偏光板用粘着シート。
- 偏光板と、前記偏光板の少なくとも一方の面に形成された請求項9または10記載の偏光板粘着剤層とを有することを特徴とする粘着剤層付き偏光板。
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CN201580014182.0A CN106104329A (zh) | 2014-03-18 | 2015-02-20 | 偏振片用粘合剂组合物、粘合剂层、粘合片以及带粘合剂层的偏振片 |
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JP2016071347A (ja) * | 2014-09-29 | 2016-05-09 | 住友化学株式会社 | 偏光板 |
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JP7212755B2 (ja) * | 2019-02-19 | 2023-01-25 | 株式会社寺岡製作所 | アクリル系粘着剤組成物及び粘着テープ、並びにその粘着テープにより固定された光学シートを有する光学装置 |
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CN107163867A (zh) * | 2016-03-07 | 2017-09-15 | 日东电工株式会社 | 光学用粘合片、带粘合剂层的偏振膜和液晶显示装置 |
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KR20190011298A (ko) * | 2016-06-16 | 2019-02-01 | 후지모리 고교 가부시키가이샤 | 점착제 조성물 및 대전 방지 표면 보호 필름 |
KR101998072B1 (ko) | 2016-06-16 | 2019-07-09 | 후지모리 고교 가부시키가이샤 | 점착제 조성물 및 대전 방지 표면 보호 필름 |
JP2018065947A (ja) * | 2016-10-20 | 2018-04-26 | 東洋インキScホールディングス株式会社 | アクリル系樹脂組成物、アクリル系フィルム、加飾フィルム及び加飾成型体 |
JP7047088B2 (ja) | 2017-11-10 | 2022-04-04 | 杉金光電(蘇州)有限公司 | 光学積層体 |
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US11262636B2 (en) | 2017-12-20 | 2022-03-01 | Lg Chem, Ltd. | Transmittance-variable film and use thereof |
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JP2020097737A (ja) * | 2018-12-14 | 2020-06-25 | 三菱ケミカル株式会社 | 粘着剤樹脂組成物、粘着剤樹脂硬化物、粘着シート及び画像表示装置積層体 |
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