Adhesive layer, adhesive film, liquid crystal panel, and organic EL panel

Abstract

The invention provides an adhesive layer, an adhesive film, a liquid crystal panel and an organic EL panel. The adhesive layer can maintain high performance even when the thickness of the adhesive layer is less than 15 [mu] m. The adhesive layer of the present invention is an adhesive layer (10) for use in bonding layers between a polarizing plate (11) and a panel (12), the adhesive layer (10) having a thickness of 1-15 [mu] m, the polarizing plate being bonded to the panel by means of the adhesive layer having a thickness of 10 [mu] m, even after durability tests of 80 DEG C * 500 h, 85 DEG C * 85% RH * 500 h, and 105 DEG C * 500 h, the adhesive layer (10) having a thickness of 1-15 [mu] m, and the adhesive layer (10) having a thickness of 1-15 [mu] m, the polarizing plate being bonded to the panel by means of the adhesive layer having a thickness of 10 [mu] m. The polarizing plate and the adhesive layer having a thickness of 10 [mu] m are free from peeling and foaming therebetween, after the adhesive layer having a thickness of 10 [mu] m is bonded to the polarizing plate and aging ends, the adhesive force after 20 minutes is 5.0 N / 25 mm or less, and the adhesive force after 23 DEG C * 10 days is 10 N / 25 mm or less after the adhesive layer having a thickness of 10 [mu] m is bonded to the alkali-free glass.

Description

Technical Field

[0001] This invention relates to adhesive layers, adhesive films, liquid crystal panels, and organic EL panels. Background Technology

[0002] Adhesive films are used in the bonding of optical components such as polarizing plates, and in the assembly or processing of components in electronic devices such as liquid crystal panels and organic EL panels. For example, Patent Document 1 describes the use of an adhesive layer formed by cross-linking an adhesive composition in the bonding of optical components such as polarizing plates.

[0003] Patent Document 1: Japanese Patent No. 5422629 Summary of the Invention

[0004] In existing technologies, the adhesive layer is 20–25 μm thick to maintain high performance. However, due to the recent demands for miniaturization and thin-film technology, it is necessary to reduce the thickness of the adhesive layer. But, if the adhesive layer is actually thinned, it is difficult to maintain the performance that can be achieved in the past.

[0005] The present invention was made in view of the above circumstances, and its object is to provide an adhesive layer, adhesive film, liquid crystal panel and organic EL panel that can maintain high performance even when the thickness of the adhesive layer is less than 15 μm.

[0006] The present invention includes the following solutions.

[0007] [1] An adhesive layer for bonding a polarizing plate to a panel, characterized in that the thickness of the adhesive layer is 1 to 15 μm, wherein when the polarizing plate is bonded to the panel using the 10 μm thick adhesive layer, even after a durability test at 80°C for 500 h, there is neither peeling nor foaming between the polarizing plate and the 10 μm thick adhesive layer; when the polarizing plate is bonded to the panel using the 10 μm thick adhesive layer, even after a durability test at 85°C for 85% RH for 500 h, there is neither peeling nor foaming between the polarizing plate and the 10 μm thick adhesive layer; when the polarizing plate is bonded to the panel using the 10 μm thick adhesive layer, even after a durability test at 85°C for 85% RH for 500 h, there is neither peeling nor foaming between the polarizing plate and the 10 μm thick adhesive layer. The 10μm adhesive layer is bonded to the panel. Even after a durability test at 105°C for 500 hours, there is neither peeling nor foaming between the polarizing plate and the 10μm thick adhesive layer. After the aging process is completed by bonding the 10μm thick adhesive layer to the polarizing plate, the adhesive layer is bonded to alkali-free glass. After 20 minutes, the adhesion strength is less than 5.0N / 25mm. After the aging process is completed by bonding the 10μm thick adhesive layer to the polarizing plate, the adhesive layer is bonded to alkali-free glass. After 23°C for 10 days, the adhesion strength is less than 10N / 25mm.

[0008] [2] The adhesive layer according to [1] is characterized in that the adhesive layer is an adhesive layer formed by crosslinking an adhesive composition comprising an acrylic polymer and a crosslinking agent (D), wherein the acrylic polymer is a copolymer formed by copolymerizing at least one (A) alkyl (meth)acrylate monomer having a carbon number of C1 to C18, at least one (B) a hydroxyl-containing copolymerizable vinyl monomer, and at least one (C) selected from the group consisting of alkoxy-containing vinyl monomers and nitrogen-containing vinyl monomers, wherein the acrylic polymer has a weight-average molecular weight of 1.5 million to 3.5 million, wherein the acrylic polymer does not contain a carboxyl-containing copolymerizable vinyl monomer, wherein the acrylic polymer has an acid value of 0.1 or less, and wherein in a total of 100 parts by mass of the acrylic polymer, the (A) alkyl (meth)acrylate monomer having a carbon number of C1 to C18 contains at least 50 parts by mass of butyl acrylate, and the (C) at least one selected from the group consisting of alkoxy-containing vinyl monomers and nitrogen-containing vinyl monomers is at least 10 parts by mass. The ratio (A) / (C) of the total mass parts of at least one of the alkyl (meth)acrylate monomers having C1 to C18 carbon atoms in (A) to the total mass parts of at least one of the vinyl monomers selected from the group consisting of alkoxy-containing vinyl monomers and nitrogen-containing vinyl monomers is 1.50 to 8.99; the (B) hydroxyl-containing copolymeric vinyl monomer is 0.1 to 2.0 parts by mass; and the (D) crosslinking agent is selected from the trimethylolpropane adduct of toluene diisocyanate and the isocyanurate of toluene diisocyanate. The adhesive composition comprises at least one of the compounds in the group consisting of said (D) crosslinking agent, wherein the adhesive composition contains 0.01 to 1.5 parts by mass relative to a total of 100 parts by mass of said acrylic polymer, and further, the adhesive composition contains 0.01 to 5.0 parts by mass relative to a total of 100 parts by mass of said (E) oligomeric silane coupling agent as a silane coupling agent, said oligomeric silane coupling agent having at least one organic functional group selected from the group consisting of epoxy, mercapto, and (meth)acryloyl.

[0009] [3] The adhesive layer according to [1] or [2] is characterized in that the gel fraction of the adhesive layer is determined by the following gel fraction determination method and is 50 to 75% by mass.

[0010] • Method for determining gel fraction: After aging by bonding the 10 μm thick adhesive layer to the polarizing plate, the mass of the test sample is accurately measured from the 10 μm thick adhesive layer on the surface of the polarizing plate. After immersion in toluene for 24 hours, the sample is filtered through a 200-mesh metal mesh. The filter material is then dried at 100°C for 1 hour, and the mass of the residue is accurately measured. The gel fraction of the adhesive layer is calculated according to the following formula (1).

[0011] Gel fraction (%) = mass of residue (g) / mass of sample to be tested (g) × 100 ··· Equation (1)

[0012] [4] The adhesive layer according to [2] is characterized in that the (B) hydroxyl-containing copolymeric vinyl monomer is selected from at least one of the group consisting of (meth)acrylate-8-hydroxyoctyl ester, (meth)acrylate-6-hydroxyhexyl ester, (meth)acrylate-4-hydroxybutyl ester, (meth)acrylate-2-hydroxyethyl ester, N-hydroxy(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, and N-hydroxyethyl(meth)acrylamide.

[0013] [5] The adhesive layer according to [2] or [4] is characterized in that the adhesive composition contains (F) as an antistatic agent and an ionic compound with a melting point of 25°C or higher in a ratio of 0.01 to 5.0 parts by weight relative to a total of 100 parts by weight of the acrylic polymer, and the adhesive layer formed by crosslinking the adhesive composition has a surface resistivity of 9.0 × 10⁻⁶. 11 Below Ω / □.

[0014] [6] The adhesive layer according to any one of [1] to [5] is characterized in that, after aging is completed by bonding the 10 μm thick adhesive layer to a polarizing plate with a thickness of 105 μm and a surface substrate of PMMA or COP, and then bonding it to a panel with a surface of alkali-free glass and a screen size of 254 mm (10 inches), even after a durability test of 105°C × 500 h, there is neither peeling nor foaming between the polarizing plate and the 10 μm thick adhesive layer.

[0015] [7] The adhesive layer according to any one of [1] to [6] is characterized in that the aging is completed by bonding the 10 μm thick adhesive layer to a polarizing plate with a thickness of 105 μm and a surface substrate of PMMA or COP, and then bonding it to a panel with a surface of alkali-free glass and a screen size of 254 mm (10 inches), even after a durability test of 85°C × 85% RH × 500 h, the haze value of the 10 μm thick adhesive layer is less than 1.5%.

[0016] [8] An adhesive film, characterized in that it is formed by laminating an adhesive layer as described in any one of [1] to [7] on one side of a resin film.

[0017] [9] An adhesive film, characterized in that it is an adhesive film for a polarizing plate using the adhesive film described in [8].

[0018]

[10] An adhesive film, characterized in that an adhesive layer as described in any one of [1] to [7] is formed on one side of a release film with a thickness of 1 to 15 μm, wherein the adhesive film has a release film / adhesive layer / release film structure.

[0019]

[11] A liquid crystal panel, characterized in that it uses a polarizing plate with an adhesive layer formed by laminating an adhesive layer of any one of [1] to [7] on one side of a polarizing plate.

[0020]

[12] An organic EL panel, characterized in that it is a polarizing panel with an adhesive layer formed by laminating an adhesive layer of any one of [1] to [7] on one side of a polarizing panel.

[0021] According to the present invention, adhesive layers, adhesive films, liquid crystal panels, and organic EL panels that can maintain high performance even when the thickness of the adhesive layer is less than 15 μm can be provided. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view illustrating an example of the use of the adhesive layer of the present invention.

[0023] Explanation of reference numerals in the attached figures

[0024] 10… Adhesive layer, 11… Polarizing plate, 12… Panel. Detailed Implementation

[0025] The present invention will now be described based on suitable embodiments.

[0026] Figure 1 An example of the use of the adhesive layer is shown. The adhesive layer 10 is used to bond the polarizing plate 11 to the panel 12 between the layers, and the thickness of the adhesive layer 10 is 1 to 15 μm.

[0027] When the adhesive layer 10 of this embodiment is made into an adhesive layer with a thickness of 10 μm, it can still maintain the same high performance as that of the adhesive layer with a thickness of 20 to 25 μm in the prior art. Specifically, the following properties can be cited. (1) to (3) represent the durability performance at high temperature or high temperature and high humidity. (4) to (5) represent the degree of increase in adhesive force after bonding.

[0028] (1) The polarizing plate was bonded to the panel with an adhesive layer of 10 μm thickness. Even after a durability test of 80℃×500h, there was no peeling or foaming between the polarizing plate and the adhesive layer of 10 μm thickness.

[0029] (2) The polarizing plate was bonded to the panel with an adhesive layer of 10 μm thickness. Even after a durability test of 85℃×85%RH×500h, there was no peeling or foaming between the polarizing plate and the adhesive layer of 10 μm thickness.

[0030] (3) The polarizing plate was bonded to the panel with an adhesive layer of 10 μm thickness. Even after a durability test of 105℃×500h, there was no peeling or foaming between the polarizing plate and the adhesive layer of 10 μm thickness.

[0031] (4) After the aging process is completed by attaching a 10μm thick adhesive layer to the polarizing plate, attach a 10μm thick adhesive layer to the alkali-free glass. After 20 minutes, the adhesion force is less than 5.0N / 25mm.

[0032] (5) After the aging process is completed by attaching a 10μm thick adhesive layer to the polarizing plate, attach a 10μm thick adhesive layer to the alkali-free glass. After 23℃×10 days, the adhesion force is less than 10N / 25mm.

[0033] The adhesive layer in this embodiment is preferably an adhesive layer formed by crosslinking an adhesive composition comprising an acrylic polymer and a crosslinking agent.

[0034] The adhesive composition of this embodiment comprises an acrylic polymer and a crosslinking agent. By crosslinking the adhesive composition of this embodiment, the adhesive layer of this embodiment can be manufactured.

[0035] In the adhesive composition of this embodiment, the acrylic polymer is preferably a copolymer formed by copolymerizing at least one of (A) alkyl (meth)acrylate monomers having a carbon number of C1 to C18, at least one of hydroxyl-containing copolymerizable vinyl monomers, and at least one of (C) vinyl monomers selected from the group consisting of alkoxy-containing vinyl monomers and nitrogen-containing vinyl monomers.

[0036] In this specification, (meth)acrylate monomer refers to a monomer with (meth)acrylate as its polymerizable functional group. (Meth)acrylate can be either acrylate or methacrylate, or a combination of both.

[0037] The alkyl group of the (A) alkyl group, which has a carbon number of C1 to C18, is a (meth)acrylate alkyl ester monomer [(A) component] and may be selected from one or more of the following: methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecanyl, octadecyl, cyclopentyl, cyclohexyl, etc.

[0038] (A) The alkyl group of the component can be either acyclic (linear or branched) or cyclic. Specific examples of linear alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-octyl, n-nonyl, n-decyl, lauryl, myristyl, palmityl, stearyl, etc. Specific examples of branched alkyl groups include isopropyl, isobutyl, sec-butyl, tert-butyl, isooctyl, 2-ethylhexyl, 2-octyl, isononyl, isodecyl, isomalmityl, isopalmityl, isostearyl, etc.

[0039] Of the total 100 parts by weight of the acrylic polymer, component (A) preferably contains at least 50 parts by weight of butyl acrylate, and more preferably contains at least 50 parts by weight of n-butyl acrylate.

[0040] As the hydroxyl-containing copolymeric vinyl monomer (component (B)), examples include monomers having hydroxyl groups and containing one unsaturated double bond as a polymerizable functional group within the molecule, such as vinyl, allyl, or (meth)acrylate groups. The (meth)acrylate group is preferably the unsaturated double bond in component (B). Component (B) is a monomer that does not contain a carboxyl group.

[0041] As a specific example of component (B), at least one can be selected from the group consisting of 8-hydroxyoctyl methacrylate, 6-hydroxyhexyl methacrylate, 4-hydroxybutyl methacrylate, 2-hydroxyethyl methacrylate, N-hydroxy(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, and N-hydroxyethyl(meth)acrylamide.

[0042] As at least one of the groups selected from alkoxy-containing vinyl monomers and nitrogen-containing vinyl monomers [component (C)], examples include monomers containing an alkoxy or nitrogen atom and having an unsaturated double bond as a polymerizable functional group within the molecule, said unsaturated double bond being vinyl, allyl, (meth)acrylate, etc. Component (C) is a monomer that contains neither hydroxyl nor carboxyl groups.

[0043] Examples of vinyl monomers containing alkoxy groups include those with the general formula CH2=CH(R) 1 )-CO-O-(R 2 O)nR 3 (where R) 1 R is a hydrogen atom or a methyl group. 2 It is an alkylene group, R 3 Compounds represented by alkyl groups and n being an integer greater than or equal to 1.

[0044] R in the above general formula 2 The alkylene group can be selected from one or more of ethylene, propylene, butylene, etc. As R 3 Alkyl groups can be exemplified by methyl, ethyl, etc. Specific examples of vinyl monomers containing alkoxy groups include (meth)acrylate methoxyalkyl acrylate, (meth)acrylate ethoxyalkyl acrylate, methoxypolyalkylene glycol (meth)acrylate, ethoxypolyalkylene glycol (meth)acrylate, etc.

[0045] There are no particular limitations on the nitrogen-containing vinyl monomers, and examples include N,N-dialkyl-substituted acrylic monomers, N-vinyl-substituted lactams, and N-(meth)acryloyl-substituted cyclic amines. Examples of N,N-dialkyl-substituted acrylic monomers (containing amino or amide groups) include N,N-dialkyl(meth)acrylamide, (meth)acrylate (dialkylamino)alkyl ester, and (dialkylamino)alkyl(meth)acrylamide. The alkyl group in N,N-dialkyl-substituted acrylic monomers can be selected from one or more of methyl, ethyl, propyl, and butyl groups. Examples of N-vinyl-substituted lactams include N-vinylpyrrolidone and N-vinylcaprolactam. Examples of N-(meth)acryloyl-substituted cyclic amines include N-(meth)acryloylpyrrolidine, N-(meth)acryloylpiperidine, and N-(meth)acryloylmorpholine.

[0046] To maintain high performance even when the adhesive layer thickness is less than 15 μm, it is preferable that, in 100 parts by mass of the total acrylic polymer, component (C) is 10 parts by mass or more, the ratio of the mass of component (A) to the mass of component (C) ((A) / (C)) is 1.50 to 8.99, and component (B) is 0.1 to 2.0 parts by mass. Furthermore, it is preferable that the acrylic polymer does not contain carboxyl-containing copolymerizable vinyl monomers, and that the acrylic polymer has an acid value of 0.1 or less. The low-acid-value acrylic polymer is obtained by copolymerizing monomers without using acidic functional groups such as carboxyl groups.

[0047] To maintain high performance even when the adhesive layer thickness is less than 15 μm, the weight-average molecular weight (MW) of the acrylic polymer is preferably between 1.5 million and 3.5 million. There are no particular limitations on the polymerization method for the copolymer used as the acrylic polymer; known polymerization methods such as solution polymerization and emulsion polymerization are suitable.

[0048] The adhesive composition of this embodiment contains a (D) crosslinking agent [(D) component]. As the (D) component, a polyisocyanate compound with two or more functionalities is preferred, and a polyisocyanate compound with three or more functionalities is more preferred. In order to maintain high performance even when the thickness of the adhesive layer is 15 μm or less, the (D) component is preferably at least one selected from the group consisting of a trimethylolpropane adduct of toluene diisocyanate and an isocyanurate compound of toluene diisocyanate. The proportion of the (D) component relative to 100 parts by weight of the total acrylic polymer is preferably 0.01 to 1.5 parts by weight.

[0049] The gel fraction of the adhesive layer formed by crosslinking the adhesive composition containing component (D) is preferably determined by the gel fraction determination method described below, and is 50 to 75% by mass.

[0050] • Method for determining gel fraction: After aging, a 10 μm thick adhesive layer is bonded to a polarizing plate. The mass of the sample is accurately measured from the 10 μm thick adhesive layer on the surface of the polarizing plate. After immersion in toluene for 24 hours, the sample is filtered through a 200-mesh metal mesh. The filter material is then dried at 100°C for 1 hour, and the mass of the residue is accurately measured. The gel fraction of the adhesive layer is calculated according to the following formula (1).

[0051] Gel fraction (%) = mass of residue (g) / mass of sample to be tested (g) × 100 ··· Equation (1)

[0052] The adhesive composition of this embodiment contains an (E) silane coupling agent [(E) component]. Examples of the (E) component include oligomeric silane coupling agents having at least one organic functional group selected from the group consisting of epoxy, mercapto, and (meth)acryloyl groups. The proportion of the (E) component is preferably 0.01 to 5.0 parts by mass relative to 100 parts by mass of the total acrylic polymer. Compared to monomeric silane coupling agents having one alkoxysilyl group, oligomeric silane coupling agents have a greater number of reactive organic functional groups.

[0053] The adhesive composition of this embodiment preferably contains an antistatic agent (F) [component (F)]. Examples of component (F) include ionic compounds with a melting point of 25°C or higher. The proportion of component (F) relative to 100 parts by mass of the total acrylic polymer is preferably 0.01 to 5.0 parts by mass. The surface resistivity of the adhesive layer formed by crosslinking the adhesive composition containing component (E) is preferably 9.0 × 10⁻⁶. 11 Below Ω / □.

[0054] Cations that are ionic compounds can be selected from the group consisting of pyridinium, imidazolium, sulfonium, phosphonium, pyrrolidineonium, guanidine, ammonium, isoureaonium, thioureaonium, piperidinium, pyrazoliumonium, methylonium, lithium, and ammonium. Among these, cations other than lithium (Li) can have one or more substituents. Examples of substituents include alkyl, phenyl, and benzyl hydrocarbon groups.

[0055] Examples of anions that can be considered as ionic compounds include sulfonate anions (XSO3). - ), imide anion (X2N) - ), Methyl anion (X3C) - ), borate anion (X4B) - Examples of anions include those containing fluorine atoms, such as X. Examples of sulfonate anions include fluoroalkane sulfonate anions. Examples of imide anions include bis(fluorosulfonyl)imide anions. Examples of borate anions include tetra(fluorophenyl)borate anions.

[0056] In addition to the examples shown above, the adhesive composition of this embodiment may also be suitably combined with any known additives such as antioxidants, surfactants, plasticizers, fillers, crosslinking catalysts, crosslinking promoters, and crosslinking delayers as any component. They may be used alone or in combination of two or more.

[0057] The adhesive layer in this embodiment is an adhesive layer with a thickness of 1 to 15 μm. When making an adhesive layer with a thickness of 10 μm, in addition to having the above-mentioned (1) to (5), it is preferable to also have at least one of the following properties (6) to (8).

[0058] (6) The aging process is completed by attaching a 10 μm thick adhesive layer to the specified polarizing plate and then attaching it to the specified panel. Even after a durability test of 105°C × 500h, there is no peeling or foaming between the polarizing plate and the 10 μm thick adhesive layer.

[0059] (7) The aging process is completed by attaching a 10 μm thick adhesive layer to the specified polarizing plate and then attaching it to the specified panel. Even after a durability test of 85°C × 85% RH × 500h, there is no peeling or foaming between the polarizing plate and the 10 μm thick adhesive layer.

[0060] (8) The aging process is completed by attaching a 10 μm thick adhesive layer to the specified polarizing plate and then attaching it to the specified panel. Even after a durability test of 85°C × 85%RH × 500h, the haze value of the 10 μm thick adhesive layer is less than 1.5%.

[0061] In (6) to (8) above, a polarizing plate with a thickness of 105 μm and a surface substrate of polymethyl methacrylate (PMMA) or cyclic olefin polymer (COP) can be cited as an example. A panel with a surface of alkali-free glass and a screen size of 254 mm (10 inches) can be cited as an example.

[0062] The adhesive film of this embodiment can be a structure formed by laminating the adhesive layer of this embodiment onto one side of a resin film. The adhesive film of this embodiment can also be a release film / adhesive layer / release film structure in which the adhesive layer of this embodiment is formed on one side of a release film with a thickness of 1 to 15 μm. The adhesive film of this embodiment can be used as an adhesive film for polarizing plates.

[0063] The adhesive film of this embodiment can be used for interlayer bonding of optical components such as polarizing plates and panels. The application of the adhesive film is not particularly limited, and examples include electronic devices such as liquid crystal panels, organic EL panels, and touch panels, or various optical films. Examples of optical films include polarizing films, retardation films, lens films, anti-reflective films, hard coating films, transparent conductive films, anti-glare films, ultraviolet absorption films, infrared absorption films, optical compensation films, and brightness enhancement films.

[0064] The adhesive-coated optical film of this embodiment has a structure in which the aforementioned adhesive layer is laminated on at least one side of the optical film. When used as an optical film in a polarizing plate, the adhesive-coated polarizing plate, formed by laminating an adhesive layer on one side of the polarizing plate, can be used in electronic devices such as liquid crystal panels, organic EL panels, and touch panels.

[0065] As a surface treatment applied to the surface of a polarizing plate such as a polarizing film, it can be at least one selected from the group consisting of untreated, AG treatment, LR treatment, AR treatment, AG-LR treatment, and AG-AR treatment. Here, AG refers to anti-glare, LR refers to low-reflection, and AR refers to anti-reflection.

[0066] Example

[0067] The present invention will now be specifically described with reference to specific embodiments.

[0068] <Manufacturing of Acrylic Polymers>

[0069] Nitrogen gas was introduced into a reaction apparatus equipped with a stirrer, thermometer, reflux cooler, and nitrogen inlet tube to replace the air in the apparatus. Then, monomers (A), (B), and (C) shown in Table 1 and solvent (ethyl acetate) were added, and polymerization was carried out simultaneously with the dropwise addition of azobisisobutyronitrile (AIBN) as a polymerization initiator, to obtain an acrylic polymer solution.

[0070] The abbreviations for the materials used in Table 1 have the following meanings. In columns (A) to (F) of Table 1, the numerical values ​​following the abbreviations represent the parts by mass.

[0071] (A)Group

[0072] ·BA: Butyl acrylate (preferably n-butyl acrylate)

[0073] ·EA: Ethyl acrylate

[0074] MA: Methyl acrylate

[0075] MMA: Methyl methacrylate

[0076] •TBA: tert-butyl acrylate

[0077] PHEA: Phenoxyethyl acrylate

[0078] Group (B)

[0079] ·8HOA: 8-Hydroxyoctyl Acrylate

[0080] ·6HHA: 6-Hydroxyhexyl acrylate

[0081] 4HBA: 4-Hydroxybutyl acrylate

[0082] HEA: 2-Hydroxyethyl Acrylate

[0083] AAc: Acrylic acid

[0084] Group (C)

[0085] C-1: Methoxylated polyethylene glycol methacrylate

[0086] C-2: Methoxyethyl acrylate

[0087] C-3: Dimethylaminoethyl acrylate

[0088] C-4: Dimethylacrylamide

[0089] C-5: N-vinyl-2-pyrrolidone

[0090] (D) (TAKENATE (registered trademark) is a trade name of Mitsui Chemicals Co., Ltd.)

[0091] • D-1: TAKENATE (registered trademark) D101E, trimethylolpropane (TMP) adduct of toluene diisocyanate (TDI) (75% ethyl acetate solution)

[0092] • D-2: TAKENATE (registered trademark) D262, Toluene diisocyanate (TDI), isocyanurate compound (75% butyl acetate solution)

[0093] • D-3: TAKENATE (registered trademark) D-160N, trimethylolpropane (TMP) adduct of hexamethylene diisocyanate (HDI) (75% ethyl acetate solution)

[0094] D-4: Benzoyl peroxide

[0095] (E) Group (all are trade names of Shin-Etsu Chemical Co., Ltd.)

[0096] E-1: KR-519, a mercapto-containing oligomer

[0097] E-2: KR-516, an epoxy-containing oligomer

[0098] E-3: X-12-1154, a mercapto-containing oligomer

[0099] E-4: KR-513, an acryloyl oligomer

[0100] E-5: KBM-403, an epoxy-containing silane coupling agent (monomer type).

[0101] Group (F)

[0102] F-1: Tributylmethylammonium N,N-bis(trifluoromethanesulfonyl)imide (melting point 27℃)

[0103] F-2: 1-Methyl-3-octylpyridinium nonafluorobutane sulfonate (melting point 41℃)

[0104] F-3: Methoxymethyltriphenylphosphonium tetra(pentafluorophenyl)borate (melting point 149℃)

[0105] F-4: 1-Butyrylpyridinium bis(trifluoromethanesulfonyl)imide (liquid)

[0106] [Table 1]

[0107]

[0108] <Methods for measuring adhesive strength>

[0109] A 10 μm thick adhesive layer was transferred onto one side of a polarizing plate to form a sample. The sample was then bonded to alkali-free glass using a 2 kg roller in one pass, and the adhesive strength was measured. For the adhesive strength determination, samples were prepared that were bonded to alkali-free glass and had their adhesive strength measured after 20 minutes, and samples were also prepared that were bonded to alkali-free glass and had their adhesive strength measured after 10 days at 23°C.

[0110] <Methods for determining gel fraction>

[0111] According to the durability test method described below, a test sample was collected from the adhesive layer after aging was completed, and the mass of the test sample was accurately measured. After being immersed in toluene for 24 hours, the sample was filtered through a 200-mesh metal mesh. Afterward, the filter material was dried at 100°C for 1 hour, and the mass of the residue was accurately measured. The gel fraction excluding the adhesive layer was calculated according to the following formula (1).

[0112] Gel fraction (%) = mass of residue (g) / mass of sample to be tested (g) × 100 ··· Equation (1)

[0113] <Methods for measuring surface resistivity>

[0114] Following the durability testing method described below, the surface resistivity of the adhesive layer was measured using a resistivity meter after the aging process of the adhesive layer was completed. In Table 2, the surface resistivity values ​​are expressed as "m × 10⁻⁶". +n It is represented as “mE+n” (where m is a decimal and n is an integer).

[0115] <Methods for Determining Durability>

[0116] A 10μm thick adhesive layer was transferred onto one side of the polarizing plate and aged at 23℃ for 4 days. Then, it was bonded to a 0.7mm thick alkali-free glass (EAGLE XG (registered trademark)) as the substrate and subjected to autoclave treatment at 50℃ for 5 atmospheres for 20 minutes. After that, the sample was placed in a specified durability atmosphere (3 conditions: 80℃, 85℃ for 85% RH, and 105℃). After a specified time (500h), it was taken out and the state between the polarizing plate and the adhesive layer (whether there was peeling or foaming) was checked with a magnifying glass.

[0117] ○: No peeling or foaming

[0118] △: Slight peeling, with foaming

[0119] ×: Peeling, foaming

[0120] <Methods for measuring haze>

[0121] Following the durability testing method described above, after the aging of the adhesive layer was completed, the haze value (%) of the adhesive layer was measured using a haze meter (trade name: NDH4000) manufactured by Nippon Denshoku Kogyo Co., Ltd., in accordance with JIS K7136.

[0122] [Table 2]

[0123]

[0124] When a polarizing plate is used in the evaluation in Table 2, a polarizing plate having the surface substrate (PMMA or COP) shown in Table 2 is used as the polarizing plate.

[0125] According to Examples 1 to 5, high performance can be maintained even when the thickness of the adhesive layer is less than 15 μm.

[0126] According to Comparative Examples 1 to 4, high performance could not be maintained when the thickness of the adhesive layer was less than 15 μm.

Claims

1. An adhesive layer for bonding a polarizing plate to a panel, characterized in that, The thickness of the adhesive layer is 1–15 μm. The polarizing plate was bonded to the panel using the adhesive layer with a thickness of 10 μm. Even after a durability test at 80°C for 500 hours, there was neither peeling nor foaming between the polarizing plate and the adhesive layer with a thickness of 10 μm. The polarizing plate was bonded to the panel using the adhesive layer with a thickness of 10 μm. Even after a durability test at 85°C × 85% RH × 500 h, there was neither peeling nor foaming between the polarizing plate and the adhesive layer with a thickness of 10 μm. The polarizing plate was bonded to the panel using the adhesive layer with a thickness of 10 μm. Even after a durability test at 105°C for 500 hours, there was neither peeling nor foaming between the polarizing plate and the adhesive layer with a thickness of 10 μm. After the aging process was completed by bonding the 10μm thick adhesive layer to the polarizing plate, the 10μm thick adhesive layer was then bonded to alkali-free glass. After 20 minutes, the adhesion strength was less than 5.0N / 25mm. After the aging process is completed by bonding the 10μm thick adhesive layer to the polarizing plate, the 10μm thick adhesive layer is then bonded to alkali-free glass. After 23°C for 10 days, the adhesion strength is less than 10N / 25mm.

2. The adhesive layer according to claim 1, characterized in that, The adhesive layer is an adhesive layer formed by crosslinking an adhesive composition comprising an acrylic polymer and a (D) crosslinking agent. The acrylic polymer is for making (A) At least one alkyl (meth)acrylate monomer having a carbon number of C1 to C18. (B) at least one hydroxyl-containing copolymeric vinyl monomer, and (C) Select at least one from the group consisting of alkoxy-containing vinyl monomers and nitrogen-containing vinyl monomers. copolymers formed by copolymerization The weight-average molecular weight of the acrylic polymer is 1.5 million to 3.5 million. The acrylic polymer does not contain carboxyl-containing copolymeric vinyl monomers, and the acrylic polymer has an acid value of 0.1 or less. Of the total 100 parts by mass of the acrylic polymer, the (A) alkyl (meth)acrylate alkyl ester monomer with C1 to C18 carbon atoms contains at least 50 parts by mass of butyl acrylate, the (C) at least one selected from the group consisting of alkoxy-containing vinyl monomers and nitrogen-containing vinyl monomers is at least 10 parts by mass, the ratio of the total mass of the (A) alkyl (meth)acrylate alkyl ester monomer with C1 to C18 carbon atoms to the total mass of the (C) at least one selected from the group consisting of alkoxy-containing vinyl monomers and nitrogen-containing vinyl monomers ((A) / (C)) is 1.50 to 8.99, and the (B) hydroxyl-containing copolymeric vinyl monomer is 0.1 to 2.0 parts by mass. The (D) crosslinking agent is at least one selected from the group consisting of trimethylolpropane adducts of toluene diisocyanate and isocyanurate compounds of toluene diisocyanate. The adhesive composition contains 0.01 to 1.5 parts by weight of the (D) crosslinking agent relative to a total of 100 parts by weight of the acrylic polymer. Furthermore, the adhesive composition contains 0.01 to 5.0 parts by weight of (E) as a silane coupling agent in a total of 100 parts by weight relative to the acrylic polymer, the oligomeric silane coupling agent having at least one organic functional group selected from the group consisting of epoxy, mercapto, and (meth)acryloyl groups.

3. The adhesive layer according to claim 1, characterized in that, The gel fraction of the adhesive layer is determined by the following gel fraction determination method and is 50-75% by mass. • Method for determining gel fraction: After aging by bonding the 10 μm thick adhesive layer to the polarizing plate, the mass of the test sample from the 10 μm thick adhesive layer on the surface of the polarizing plate is accurately measured. After immersion in toluene for 24 hours, the sample is filtered through a 200-mesh metal mesh. The filter material is then dried at 100°C for 1 hour, and the mass of the residue is accurately measured. The gel fraction of the adhesive layer is calculated according to the following formula (1). Gel fraction (%) = mass of residue (g) / mass of sample to be measured (g) × 100 ··· Equation (1).

4. The adhesive layer according to claim 2, characterized in that, The (B) hydroxyl-containing copolymeric vinyl monomer is selected from at least one of the following groups: 8-hydroxyoctyl methacrylate, 6-hydroxyhexyl methacrylate, 4-hydroxybutyl methacrylate, 2-hydroxyethyl methacrylate, N-hydroxy(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, and N-hydroxyethyl(meth)acrylamide.

5. The adhesive layer according to claim 2, characterized in that, The adhesive composition contains (F) as an antistatic agent, an ionic compound with a melting point of 25°C or higher, in a proportion of 0.01 to 5.0 parts by weight relative to a total of 100 parts by weight of the acrylic polymer. The surface resistivity of the adhesive layer formed by crosslinking the adhesive composition is 9.0 × 10⁻⁶. 11 Below Ω / □.

6. The adhesive layer according to claim 1, characterized in that, The 10μm thick adhesive layer was bonded to a 105μm thick polarizing plate with a PMMA or COP substrate to complete the aging process. It was then bonded to a 10-inch panel with an alkali-free glass surface and a screen size of 254mm. Even after a durability test at 105℃ for 500 hours, there was neither peeling nor foaming between the polarizing plate and the 10μm thick adhesive layer. The 10μm thick adhesive layer was bonded to a 105μm thick polarizing plate with a PMMA or COP substrate to end the aging process. Then it was bonded to a panel with an alkali-free glass surface and a screen size of 254mm (10 inches). Even after a durability test of 85°C × 85%RH × 500h, there was neither peeling nor foaming between the polarizing plate and the 10μm thick adhesive layer.

7. The adhesive layer according to claim 6, characterized in that, The 10μm thick adhesive layer was bonded to a 105μm thick polarizing plate with a PMMA or COP substrate to end the aging process. Then it was bonded to a panel with an alkali-free glass surface and a screen size of 254mm (10 inches). Even after a durability test of 85°C × 85%RH × 500h, the haze value of the 10μm thick adhesive layer was below 1.5%.

8. An adhesive film, characterized in that, It is formed by laminating an adhesive layer according to any one of claims 1 to 7 onto one side of a resin film.

9. An adhesive film, characterized in that, An adhesive film for a polarizing plate using the adhesive film of claim 8.

10. An adhesive film, characterized in that, An adhesive layer according to any one of claims 1 to 7 is formed on one side of the release film with a thickness of 1 to 15 μm, wherein the adhesive film has a release film / adhesive layer / release film structure.

11. A liquid crystal panel, characterized in that, A polarizing plate with an adhesive layer, formed by laminating an adhesive layer of any one of claims 1 to 7 on one side of a polarizing plate.

12. An organic EL panel, characterized in that, A polarizing plate with an adhesive layer, formed by laminating an adhesive layer of any one of claims 1 to 7 on one side of a polarizing plate.

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