TWI766971B - Adhesive composition, adhesive, adhesive sheet, and optical component - Google Patents

Abstract

The present invention provides an adhesive composition that exhibits excellent constant load peel resistance while forming a particularly thin adhesive layer. The adhesive composition of the present invention contains a (meth)acrylic random polymer and a (meth)acrylic triblock polymer, the (meth)acrylic triblock polymer passing through gel permeation chromatography The weight average molecular weight (Mw) measured by the method is 3,000 to 30,000.

Description

Adhesive composition, adhesive, adhesive sheet, and optical component

The present invention relates to an adhesive composition, an adhesive, an adhesive sheet, and an optical member.

In the past, a lot of research has been done to improve the performance of adhesives. For example, Patent Document 1 discloses a polymer modifier for binder addition, which is excellent in compatibility with various polymers, does not see cloudiness or segregation when added to various polymers, and has an excellent modification effect. . However, the present inventors found that in the case of forming a particularly thin adhesive layer, there is a large room for improvement in the existing adhesive composition. [Background Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 4442923

[Problems to be Solved by Invention]

An object of the present invention is to provide an adhesive composition that exhibits excellent fixed-load peel tolerance while forming a particularly thin adhesive layer. Moreover, the objective of this invention is to provide the adhesive agent which consists of such an adhesive agent composition. Furthermore, an object of the present invention is to provide an adhesive sheet and an optical member including an adhesive layer formed of such an adhesive composition. [means to solve the problem]

The present inventors have made diligent studies to solve the above-mentioned problems. As a result, the present inventors found that by using a (meth)acrylic triblock polymer having a low relative molecular weight, the triblock polymer in the adhesive layer is more present on the surface, thereby obtaining particularly excellent constant load peel resistance.

Embodiments of the present invention are, for example, as follows. [1] An adhesive composition comprising a (meth)acrylic-type random polymer and a (meth)acrylic triblock polymer, the (meth)acrylic The triblock polymer has a weight average molecular weight (Mw) of 3,000 to 30,000 as measured by gel permeation chromatography. [2] The adhesive composition according to [1], wherein the compounding amount of the (meth)acrylic triblock polymer is 100 parts by mass of the (meth)acrylic random polymer in the range of 1 to 49 parts by mass. [3] The adhesive composition according to [1] or [2], wherein the (meth)acrylic triblock polymer has a structure consisting of a block [A] and a block [B] from [A] The structure represented by -[B]-[A]. [4] The adhesive composition according to any one of [1] to [3], further containing an isocyanate-based crosslinking agent. [5] The adhesive composition according to any one of [1] to [4], which is used for optical applications. [6] An adhesive formed from the adhesive composition of any one of [1] to [5]. [7] An adhesive sheet comprising a substrate and an adhesive layer formed on at least one side of the substrate using the adhesive composition of any one of [1] to [5]. [8] The adhesive sheet according to [7], wherein the adhesive layer has a thickness of 15 μm or less. [9] An optical member including an adhesive layer formed of the adhesive composition according to any one of [1] to [5]. [10] The optical member according to [9], wherein the adhesive layer has a thickness of 15 μm or less. [Effect of invention]

According to the present invention, it is possible to provide an adhesive composition that exhibits excellent peeling resistance under constant load when a particularly thin adhesive layer is formed. According to the present invention, there is also provided an adhesive formed from such an adhesive composition. Furthermore, according to the present invention, there can be provided an adhesive sheet and an optical member including an adhesive layer formed of such an adhesive composition.

Next, an adhesive composition, an adhesive, an adhesive sheet, and an optical member according to an embodiment of the present invention will be described.

In addition, in this specification, the expression "polymer" includes a homopolymer (homopolymer) and a copolymer (copolymer), and the expression "polymerization" includes a homopolymer and a copolymer. In addition, the compound (i is a formula number) represented by formula (i) is also abbreviated as "compound (i)". Furthermore, in this specification, (meth)acrylic acid refers to acrylic acid or methacrylic acid, (meth)acrylate refers to acrylate or methacrylate, and (meth)acryloyl group refers to acryl group or methyl group. based on acryloyl. [Adhesive composition]

The adhesive composition of one Embodiment of this invention contains a (meth)acrylic-type random polymer and a (meth)acrylic-type triblock polymer. Here, the weight average molecular weight (Mw) of the (meth)acrylic triblock polymer measured by gel permeation chromatography (GPC) is 3,000 to 30,000.

[1] (Meth)acrylic random polymer The structure of the (meth)acrylic random polymer is not particularly limited. The (meth)acrylic random polymer may be a (meth)acrylic random polymer synthesized by a general radical polymerization method, or a (meth)acrylic random polymer synthesized by a living radical polymerization method. Regular polymer. The weight average molecular weight (Mw) of the (meth)acrylic random polymer measured by the GPC method is, for example, 100,000 to 3,000,000, preferably 150,000 to 2,000,000, and more preferably 200,000 to 2,000,000. The molecular weight distribution (Mw/Mn) of the (meth)acrylic random polymer measured by the GPC method is, for example, 30.0 or less, preferably 25.0 or less, and more preferably 20.0 or less.

<Raw material monomers> As the raw material monomers of the (meth)acrylic random polymer, (meth)acrylates are mainly used, but other functional group-containing monomers and copolymerizable monomers may also be used. Wait.

<<(Meth)acrylate>> Examples of (meth)acrylates include (meth)acrylates, alkyl (meth)acrylates, alkoxyalkyl (meth)acrylates, and alkoxypolyalkylene glycol monoacrylates. (Meth)acrylate, alicyclic group or aromatic ring-containing (meth)acrylate. Among them, functional group-containing (meth)acrylates such as hydroxyl group-containing (meth)acrylates, carboxyl group-containing (meth)acrylates, and amino group-containing (meth)acrylates are removed from (meth)acrylates .

The number of carbon atoms of the alkyl group in the alkyl (meth)acrylate is preferably 1 to 20. Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, and (meth)acrylate. ) n-butyl acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate (tert-butyl (meth)acrylate), amyl (meth)acrylate, hexyl (meth)acrylate, Heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, ten (meth)acrylate Monoalkyl ester, lauryl (meth)acrylate, oleyl (meth)acrylate, n-stearyl (meth)acrylate, iso-stearyl (meth)acrylate (meth)acrylate , Didecyl (meth)acrylate.

Examples of (meth)acrylate alkoxyalkyl esters include methoxymethyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, and 2-ethoxy (meth)acrylate. Ethyl ester, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, 4-ethyl (meth)acrylate oxybutyl ester.

Examples of the alkoxy polyalkylene glycol mono(meth)acrylate include Methoxydiethylene glycol mono(meth)acrylate, Methoxydiethylene glycol mono(meth)acrylate, Methoxydipropylene glycol Mono(meth)acrylate, Ethoxydiethylene glycol mono(meth)acrylate, Ethoxydiethylene glycol mono(meth)acrylate, Methoxydiethylene glycol mono(meth)acrylate Methoxytriethylene glycol mono (meth) acrylate.

As an alicyclic group or an aromatic ring containing (meth)acrylate, (meth)acrylate cyclohexyl, (meth)acrylate, and (meth)acrylate are mentioned, for example.

The total amount of (meth)acrylate used is, for example, 70 to 99.9 mass %, preferably 80 to 99.5 mass %, and more preferably 89.95 to 98.95 mass % with respect to the total mass of all raw material monomers.

(Meth)acrylate can be used individually by 1 type or in 2 or more types.

<<Functional Group-Containing Monomer>> Examples of the functional group-containing monomer include hydroxyl group-containing monomers, acid group-containing monomers, amino group-containing monomers, amide group-containing monomers, nitrogen-containing hetero Cyclic monomers, cyano-containing monomers. As an acid group, a carboxyl group, an acid anhydride group, a phosphoric acid group, and a sulfuric acid group are mentioned, for example.

Examples of the hydroxyl group-containing monomer include hydroxyl group-containing (meth)acrylates, and specific examples thereof include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and (meth)acrylate. Hydroxyalkyl (meth)acrylates such as 4-hydroxybutyl acrylate, 6-hydroxyhexyl (meth)acrylate, and 8-hydroxyoctyl (meth)acrylate. The carbon number of the alkyl group in a hydroxyalkyl (meth)acrylate is 2-8 normally, Preferably it is 2-6.

Examples of the carboxyl group-containing monomer include β-carboxyethyl (meth)acrylate, 5-carboxypentyl (meth)acylate (meth)acrylate, and mono(meth)propylene succinate. Succinic acid mono (meth) acryloyloxyethyl ester, ω-carboxy polycaprolactone mono(meth)acrylate, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, fumaric acid, horse to acid. As an acid anhydride group-containing monomer, maleic anhydride is mentioned, for example. Examples of the phosphoric acid group-containing monomer include (meth)acrylic monomers having a phosphoric acid group in the side chain, and examples of the sulfuric acid group-containing monomer include (meth)acrylic monomers having a sulfuric acid group in the side chain. body.

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(methyl) base) acrylamide, N-hexyl (meth) acrylamide. Examples of the nitrogen-containing heterocyclic monomer include vinylpyrrolidone, acrylmorpholine, and vinylcaprolactam. Examples of the cyano group-containing monomer include cyano (meth)acrylate and (meth)acrylonitrile.

The total amount of the functional group-containing monomer used is preferably 0 to 10% by mass, more preferably 0.05 to 5% by mass, based on the total mass of all the raw material monomers.

The functional group-containing monomer may be used alone or in two or more.

<<Copolymerizable Monomer>> Examples of comonomers include styrene, methylstyrene, dimethylstyrene, trimethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene Alkylstyrene such as oxystyrene and octylstyrene, fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, iodized styrene, nitrostyrene, acetylstyrene and methoxybenzene Styrenic monomers such as ethylene, vinyl acetate.

A comonomer may be used individually by 1 type, or may use 2 or more types.

[2] (Meth)acrylic triblock polymer The (meth)acrylic triblock polymer used in the present invention has a weight average molecular weight (Mw) of 3,000 to 30,000 as measured by the GPC method. The weight average molecular weight (Mw) is preferably 3,000 to 20,000, more preferably 3,000 to 10,000. In addition, the molecular weight distribution (Mw/Mn) of the (meth)acrylic random polymer measured by the GPC method is, for example, 1.5 or less, preferably 1.4 or less, and more preferably 1.3 or less.

As described above, the present inventors have found that by using a (meth)acrylic triblock polymer having a low relative molecular weight, the triblock polymer is more present on the surface in the adhesive layer, so that a particularly excellent constant Load peel resistance. If the weight average molecular weight is too large, the triblock polymer in the adhesive layer does not significantly more exist on the surface, and therefore, it is difficult to achieve excellent constant load peel resistance. On the other hand, if the weight average molecular weight is too small, the adhesive composition becomes insufficient in cohesive force, and it becomes difficult to achieve excellent constant-load peeling resistance.

The synthesis method of the (meth)acrylic triblock polymer used in the present invention is not particularly limited. The (meth)acrylic triblock polymer may be a (meth)acrylic triblock polymer synthesized by a general radical polymerization method, or may be a (meth)acrylic acid synthesized by a living radical polymerization method It is a triblock polymer.

Triblock polymers can be produced using general living radical polymerization. Among them, in terms of the ease of control of the polymerization reaction, etc., it can be appropriately produced by atom transfer radical polymerization. Atom transfer radical polymerization is a polymerization method in which an organic halide or a sulfohalide compound is used as an initiator and a metal complex is used as a catalyst. In the case of producing a triblock polymer by a living radical polymerization method, a method of sequentially adding monomer units, a method of polymerizing the next polymer block using a polymer synthesized in advance as a polymer initiator, A triblock polymer is preferably produced by a method of bonding the polymer blocks separately polymerized by reaction, etc., by a method of sequentially adding monomer units.

The (meth)acrylic triblock polymer can also be synthesized by, for example, reversible addition-fragmentation chain transfer (RAFT) polymerization. If RAFT polymerization is used, the molecular weight and molecular weight distribution of the (meth)acrylic triblock polymer can be controlled more precisely.

The RAFT polymerization method is a method of polymerizing a radically polymerizable compound as a raw material monomer in the presence of a RAFT agent. All the raw material monomers may be added at one time and polymerized, or after a part of the raw material monomers may be polymerized, the remaining monomer components may be continuously or intermittently added and polymerized.

<RAFT agent> As the RAFT agent, a conventionally known compound can be used, and it is not particularly limited. Examples of RAFT agents include sulfuric acid such as Bis (thiocarbonyl) disulfide, dithioester, trithiocarbonate, dithiocarbamate, and xanthate. Substituted carbonyl sulfide compounds. Separately, as a bis (thiocarbonyl) disulfide compound (bis (thiocarbonyl) disulfide compound), for example, tetraethylthiuram disulfide, tetramethylthiuram disulfide, bis(n-octylsulfide) can be mentioned. Alcohol (octylmercapto)-thiocarbonyl) disulfide, bis(n-dodecylthiol-thiocarbonyl) disulfide, bis(benzylthiol-thiocarbonyl) disulfide, bis(benzylmercapto-thiocarbonyl) disulfide (n-butylthiol-thiocarbonyl) disulfide, bis(tert-butylthiol-thiocarbonyl) disulfide, bis(n-heptylthiol-thiocarbonyl) disulfide , bis(n-hexylthiol-thiocarbonyl) disulfide, bis(n-pentylthiol-thiocarbonyl) disulfide, bis(n-nonylthiol-thiocarbonyl) disulfide , bis(n-decylthiol-thiocarbonyl) disulfide, bis(3-dodecylthiol-thiocarbonyl) disulfide, bis(n-tetradecylthiol- thiocarbonyl) disulfide, bis(n-hexadecylthiol-thiocarbonyl) disulfide, bis(n-octadecylthiol-thiocarbonyl) disulfide, etc.; as disulfide Ester compounds, for example, 2-phenyl-2-propylbenzothioate (2-phenyl-2-propylbenzothioate), 4-cyano-4-(phenylthiocarbonylthiol)valeric acid, 2- -Cyano-2-propylbenzodithioate (2-Cyano-2-propylbenzodithioate) etc.; Examples of trithiocarbonate compounds include S-(2-cyano-2-propyl)-S- Dodecyltrithiocarbonate, 4-cyano-4-[(dodecylthiol-thiocarbonyl)thiol]valeric acid, cyanomethyldodecyltrithiocarbonate Salt, 2-(dodecylthiocarbonothiolthio)-2-methylpropionic acid, bis[4-{ethyl-2-(hydroxyethyl)aminocarbonyl}-benzyl base] trithiocarbonate, etc.; As the dithiocarbamate compound, for example, cyanomethyl methyl (phenyl) dithiocarbamate, cyanomethyl diphenyl dithioamino Formate, etc. As a xanthate compound, a xanthate etc. are mentioned, for example.

The usage-amount of a RAFT agent is 0.05-20 mass parts normally with respect to 100 mass parts of total raw material monomers, Preferably it is 0.1-10 mass parts. When the usage-amount of a RAFT agent is more than the lower limit of the said range, it becomes easy to control reaction, and when it is below the upper limit of the said range, it becomes easy to adjust the weight average molecular weight of the polymer obtained to the said range.

The RAFT polymerization is preferably carried out in the presence of a polymerization initiator. Examples of the polymerization initiator include general organic polymerization initiators, and specific examples include peroxides such as benzyl peroxide and lauryl peroxide, and azobis such as 2,2'-azobisisobutyronitrile. nitrogen compounds. A polymerization initiator may be used individually by 1 type, or may use 2 or more types.

When a polymerization initiator is used, the usage-amount of a polymerization initiator is 0.001-2 mass parts normally with respect to 100 mass parts of raw material monomers, Preferably it is 0.002-1 mass part. Moreover, the usage-amount of a polymerization initiator is 0.1-3000 mol normally with respect to 1 mol of RAFT agent, Preferably it is 1-1000 mol.

<Raw material monomers> As the raw material monomers constituting each block of the (meth)acrylic triblock polymer, (meth)acrylates are mainly used, but other functional group-containing monoblocks may be further used. monomers and comonomers. Examples of (meth)acrylates, functional group-containing monomers, and copolymerizable monomers include the same raw material monomers described above for the raw material monomers of the (meth)acrylic random polymer. raw material monomer.

<Block structure> The (meth)acrylic triblock polymer used in the present invention preferably has a block [A] and a block [B] composed of [A]-[B]-[A]. represented structure. With such a configuration, structural cohesion is easily exhibited, that is, even with a relatively low molecular weight, high cohesion can be obtained, and therefore, particularly excellent constant-load peeling resistance can be obtained.

The weight of the block [A] is, for example, 10 to 90% by mass, preferably 20 to 80% by mass, and more preferably 30 to 70% by mass of the entire (meth)acrylic triblock polymer. Further, the weight of the block [B] is, for example, 10 to 90% by mass, preferably 20 to 80% by mass, and more preferably 30 to 70% by mass of the entire (meth)acrylic triblock polymer.

The block [A] is preferably formed by containing a monomer represented by the general formula CH ₂ =CY ¹ -COOY ² (Y ¹ is a hydrogen atom or a methyl group, and Y ² is an alkyl group having 1 to 20 carbon atoms). ingredients. Further, the block [B] preferably contains a monoblock represented by the general formula CH ₂ =CY ³ -COOY ⁴ (Y ³ is a hydrogen atom or a methyl group, and Y ⁴ is an alkyl group having 1 to 20 carbon atoms). body-forming components. Moreover, in this case, it is more preferable that the carbon number of the Y ² is larger than the carbon number of the Y ⁴ . With such a configuration, in the adhesive layer, the triblock polymer is more likely to exist on the surface, and particularly excellent constant-load peeling resistance can be obtained.

As a combination of Y ² and Y ⁴ that satisfies the above conditions, for example, the combinations described in Table 1 below can be mentioned. In addition, the description of the said table is only an illustration, and it does not exclude the combination of these. [Table 1]

The compounding amount of the (meth)acrylic triblock polymer having a weight average molecular weight (Mw) of 3,000 to 30,000 as measured by GPC is based on 100 parts by mass of the (meth)acrylic random polymer, for example It is 1-49 mass parts, Preferably it is 1-39 mass parts. When the blending amount of the (meth)acrylic triblock polymer is adjusted to such a range, more excellent constant-load peeling resistance can be obtained.

Moreover, the adhesive composition of this invention may further contain a triblock polymer outside the said molecular weight range, and may further contain a block polymer other than a triblock polymer.

[3] Other components The adhesive composition may further contain a cross-linking agent, a silane coupling agent, an antistatic agent, an organic solvent, an antioxidant, a light stabilizer, an anti-metal corrosion agent, a tackifier, a plasticizer, a cross-linking accelerator agents, nanoparticles, etc. as other components.

<Crosslinking agent> Examples of the crosslinking agent include isocyanate-based compounds, epoxy-based compounds, metal chelate-based compounds, and the like, which can be used without preventing the presence of more triblock polymers on the surface of the adhesive layer. It is preferable to use an isocyanate-based crosslinking agent from the viewpoint of making the adhesive layer exhibit good physical properties.

As the isocyanate-based compound, an isocyanate compound having 2 or more isocyanate groups in one molecule is usually used. As an isocyanate compound, aliphatic diisocyanate, alicyclic diisocyanate, and aromatic diisocyanate are mentioned, for example. Examples of aliphatic diisocyanates include vinyl diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 2-methyl-1,5-pentane Aliphatic diisocyanates having 4 to 30 carbon atoms, such as alkane diisocyanate, 3-methyl-1,5-pentane diisocyanate, and 2,2,4-trimethyl-1,6-hexamethylene diisocyanate. Examples of alicyclic diisocyanates include isophorone diisocyanate, cyclopentyl diisocyanate, cyclohexyl diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tetramethyl benzene Alicyclic diisocyanates having 7 to 30 carbon atoms such as xylene diisocyanate. Examples of the aromatic diisocyanate include phenylene diisocyanate, toluene diisocyanate, xylylene diisocyanate, naphthylene diisocyanate, diphenyl ether diisocyanate, diphenylmethane diisocyanate, and diphenylpropane diisocyanate. Aromatic diisocyanates with 8 to 30 carbon atoms.

As an isocyanate compound whose number of isocyanate groups in 1 molecule is 3 or more, aromatic polyisocyanate, aliphatic polyisocyanate, and alicyclic polyisocyanate are mentioned, for example. Specifically, 2,4,6-toluenetriisocyanate, 1,3,5-benzenetriisocyanate, and 4,4',4"-triphenylmethanetriisocyanate are mentioned. Furthermore, as the isocyanate compound, for example, diphenylene triisocyanate can be mentioned. Trimer of phenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, biuret or isocyanurate form of hexamethylene diisocyanate or toluene diisocyanate, trimethylolpropane and toluene diisocyanate Reaction products of isocyanates or xylylene diisocyanate (such as toluene diisocyanate or trimolecular adducts of xylylene diisocyanate), reaction products of trimethylolpropane and hexamethylene diisocyanate (such as Trimolecular adduct of hexamethylene diisocyanate), polyether polyisocyanate, polyester polyisocyanate.

As the epoxy-based compound, for example, an epoxy compound having two or more epoxy groups in one molecule is usually used. For example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, 1,3-bis(N,N-diglycidylaminomethyl) ring Hexane, N,N,N',N'-tetraglycidylm-xylylenediamine, N,N,N',N'-tetraglycidylaminophenylmethane, triglycidylisocyanuric acid Esters, m-N, N-diglycidylaminophenyl glycidyl ether, N,N-diglycidyltoluidine, N,N-diglycidylaniline. As the metal chelate compound, for example, polyvalent metal ligands such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium include alkoxides, acetylacetone, Compounds such as ethyl acetate. Specifically, aluminum isopropoxide, second aluminum butoxide, ethyl aluminum diisopropyl acetoacetate, ethyl aluminum triacetate, and aluminum triacetate pyruvate can be mentioned.

The amount of the crosslinking agent is 0.01 to 5 parts by mass, preferably 0.01 to 2 parts by mass, more preferably 100 parts by mass in total of the (meth)acrylic random polymer and the (meth)acrylic triblock polymer It is the range of 0.01-1 mass part. If the crosslinking agent is contained within the above range, a balance between durability and stress relaxation properties can be obtained.

<Silane coupling agent> Silane coupling agent makes the adhesive layer firmly adhere to the adherend such as glass substrate, and can prevent the adhesive layer from peeling off in a high humidity and heat environment. If it is combined with the block polymer, the durability improvement effect is relatively high. big.

Examples of the silane coupling agent include polymerizable unsaturated group-containing silane coupling agents such as vinyltrimethoxysilane, vinyltriethoxysilane, and methacryloyloxypropyltrimethoxysilane; 3- Glycidoxytrimethoxysilane, 3-glycidoxytriethoxysilane, 3-glycidoxymethyldimethoxysilane, 3-glycidoxymethyldiethoxysilane, 2 -(3,4-Epoxycyclohexyl)ethyltrimethoxysilane and other epoxy-containing silane coupling agents; 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-amino Amino-containing silane coupling agents such as propyltrimethoxysilane and N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane; halogen-containing silanes such as 3-chloropropyltrimethoxysilane Silane coupling agent.

Among them, an epoxy group-containing silane coupling agent is preferable in terms of stress relaxation properties and the like. In the composition of the present invention, the content of the silane coupling agent is usually 1 part by mass or less with respect to 100 parts by mass of the total of the (meth)acrylic random polymer and the (meth)acrylic triblock polymer, Preferably it is 0.01-1 mass part, More preferably, it is 0.05-0.5 mass part. If the content is within the above range, peeling of the adhesive layer in a high-humidity-heat environment or exudation of the silane coupling agent in a high-temperature environment tends to be prevented.

<Antistatic agent> As an antistatic agent, a surfactant, an ionic compound, and a conductive polymer are mentioned, for example.

Examples of the surfactant include: quaternary ammonium salts, amide quaternary ammonium salts, phenazopyridine salts, cationic surfactants having cationic groups such as primary to tertiary amino groups; sulfonate groups Anionic surfactants with anionic groups such as sulfate groups, phosphate groups, etc.; amphoteric surfactants such as alkyl betaines, alkyl imidazolinium betaines, alkyl amine oxides, amino acid sulfates, etc. , Glycerol fatty acid esters, sorbitan fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene alkylamine fatty acid esters, N-hydroxyethyl-N-2-hydroxyalkylamines, alkyl Nonionic surfactants such as diethanolamine.

In addition, as the surfactant, a reactive emulsifier having a polymerizable group can also be used, and a polymer-based interfacial active agent obtained by molecular weighting of the monomer component containing the surfactant or reactive emulsifier can also be used. agent.

The ionic compound is composed of a cation part and an anion part, and may be solid or liquid at room temperature (23°C/50%RH).

As a cation part which comprises an ionic compound, either an inorganic cation or an organic cation may be sufficient, and both may be sufficient. The inorganic cations are preferably alkali metal ions and alkaline earth metal ions, and more preferably Li ⁺ , Na ⁺ and K ⁺ which are excellent in antistatic properties. Examples of organic cations include pyridinium cations, pyridinium cations, pyrrolidinium cations, pyrroline cations, pyrrole cations, imidazolium cations, tetrahydropyrimidinium cations, dihydropyrimidinium cations, pyrazolium cations, Pyrazolinium cations, tetraalkylammonium cations, dialkyl perionium cations, tetraalkylphosphonium cations and derivatives of these.

The anion moiety constituting the ionic compound is not particularly limited as long as it can ionically bond with the cationic moiety to form an ionic compound. Specifically, F ^- , Cl ^- , Br ^- , I ^- , AlCl ₄ ^- , Al ₂ Cl ₇ ^- , BF ₄ ^- , PF ₆ ^- , SCN ^- , ClO ₄ ^- , NO ₃ ^- , CH ₃ COO ^- , CF ₃ COO ^- , CH ₃ SO ₃ ^- , CF ₃ SO ₃ ^- , (CF ₃ SO ₂ ) ₂ N ^- , (F ₂ SO ₂ ) ₂ N ^- , (CF ₃ SO ₂ ) ₃ C ^- , AsF ₆ ^- , SbF ₆ ^- , NbF ₆ ^- , TaF ₆ ^- , F(HF) _n ^- , (CN) ₂ N ^- , C ₄ F ₉ SO ₃ ^- , (C ₂ F ₅ SO ₂ ) ₂ N ^- , C ₃ F ₇ COO ^- and (CF ₃ SO ₂ )(CF ₃ CO)N ^- .

As the ionic compound, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(difluorosulfonyl)imide, lithium tris(trifluoromethanesulfonyl)methane, lithium bis(trifluoromethanesulfonyl)imide, Potassium fluoromethanesulfonyl)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(fluorosulfonyl)imide, 1 -Octyl-4-methylpyridinium bis(trifluoromethanesulfonyl)imide, (N,N-diethyl-N-methyl-N-(2-methoxyethyl)tetrafluoro Ammonium borate, bis(trifluoromethanesulfonyl)imide N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium, 1-octylpyridinium fluoroperfnium Imine (1-Octylpyridinium fluorosulfoniumimide), 1-octyl-3-methylpyridinium, trifluoropermaniumimide.

Examples of the conductive polymer include polythiophene, polyaniline, polypyrrole, and derivatives thereof.

In the composition of the present invention, the content of the antistatic agent is usually 3 parts by mass or less, relative to 100 parts by mass in total of the (meth)acrylic random polymer and the (meth)acrylic triblock polymer. Preferably it is 0.01-3 mass parts, More preferably, it is 0.05-2.5 mass parts.

<Organic solvent> The adhesive composition of the present invention does not necessarily contain a solvent, but may contain an organic solvent to adjust the coatability of the adhesive composition. In the adhesive composition of the present invention, the content of the organic solvent is usually 50 to 90% by mass, preferably 60 to 85% by mass. In addition, in this specification, "solid content" refers to all the components excluding the organic solvent among the components contained in the adhesive composition, and "solid content concentration" refers to the solid content relative to the adhesive. The ratio of the composition 100% by mass.

The use of the adhesive composition of the present invention is not limited. However, the present inventors have found that the adhesive composition of the present invention exhibits excellent performance when forming a particularly thin adhesive layer. Accordingly, the adhesive compositions of the present invention are particularly useful in optical applications. Examples of optical applications include various display devices (liquid crystal display devices, organic EL display devices, electronic paper display devices, etc.), touch panels, cameras, microscopes, and the like.

[Binder] The binder of the present invention is formed from the binder composition. The gel fraction of the binder is not particularly limited, but is usually 80% by mass or less. The gel fraction is, for example, a value measured under the conditions described in Examples.

[Adhesive Sheet] The adhesive sheet of the present invention includes: a double-sided adhesive sheet having only an adhesive layer formed on a release-treated cover film (hereinafter also referred to as a release film); A double-sided adhesive sheet of the adhesive layer (in this case, the substrate is also referred to as a core material); a single-sided adhesive sheet having a substrate and the adhesive layer formed on one side of the substrate; and in these The pressure-sensitive adhesive sheet of the pressure-sensitive adhesive sheet is attached to the surface of the pressure-sensitive adhesive layer that is not in contact with the substrate.

Examples of substrates and cover films include polyester films such as polyethylene terephthalate (PET); polyolefin films such as polycarbonate, polyethylene, polypropylene, and ethylene-vinyl acetate copolymer; polarized light Plate, retardation film, light diffusion film, brightness enhancement film and other plastic films and glass. In addition, the plastic film and glass can use various additives or a plastic film and glass laminated by a plurality of layers. In addition, in this specification, "polarizing plate" is used in the meaning containing "polarizing film". In particular, when the substrate is used for optical applications, for example, optically transparent plastic films such as those described above are suitably used. Especially when transparency is not required, woven fabrics, non-woven fabrics, etc. can be used. Textile, metal vapor deposition sheet, metal screen, other arbitrary substrates.

As a coating method of the adhesive composition, a method can be used which is formed by a known method such as spin coating, blade coating, roll coating, bar coating, blade coating, die coating, and gravure coating. Coating and drying in a specific thickness.

There is no particular upper limit on the thickness of the adhesive layer, but it is, for example, 30 μm or less, preferably 25 μm or less, more preferably 20 μm or less, still more preferably 15 μm or less, and particularly preferably 12 μm or less. μm or less. As described above, the adhesive composition of the present invention exhibits particularly excellent performance when forming a thin adhesive layer. Therefore, when the adhesive layer is a thin layer, compared with the case where the conventional composition is used, the difference in performance is remarkable.

[Optical member] The optical member of the present invention contains an adhesive layer formed of an adhesive composition. The formation method and thickness of the adhesive layer are the same as those described above.

As an example of an optical member, a polarizing plate, a liquid crystal element, a camera, a microscope, etc. are mentioned. For example, the polarizing plate includes a polarizing plate main body and an adhesive layer laminated on at least one side of the polarizing plate main body.

[Examples] Hereinafter, the present invention will be described more specifically based on Examples, but the present invention is not limited to these Examples. In the description of the following Examples and the like, unless otherwise specified, a "part" means a "mass part".

[Mw, Mn] The weight average of the (meth)acrylic random polymer and the (meth)acrylic triblock polymer was determined by gel permeation chromatography (GPC method) under the following conditions Molecular weight (Mw) and number average molecular weight (Mn).・Measuring device: HLC-8320GPC (manufactured by Tosoh Corporation) ・GPC column configuration: The following four-column connections (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 ・Standard polymer Styrene conversion

[Synthesis of (meth)acrylic random polymer] [Synthesis Examples 1 to 3] In a reaction apparatus equipped with a stirrer, a reflux cooler, a thermometer, and a nitrogen gas introduction tube, n-butyl acrylate was charged in the ratio of Table 2 (BA), acrylic acid (AA), 2-hydroxyethyl acrylate (2HEA), methacrylate (MA), and 100 parts of ethyl acetate were added, and the temperature was raised to 80° C. while introducing nitrogen gas. Next, 0.1 part of tert-butyl peroxypivalate was added, and a polymerization reaction was performed at 80° C. for 6 hours under a nitrogen atmosphere. After completion of the reaction, it was diluted with ethyl acetate to prepare a polymer solution having a solid content concentration of 30% by mass. The properties of the obtained (meth)acrylic copolymer are collectively shown in Table 2.

[Table 2]

[Synthesis of (meth)acrylic block polymer] [Synthesis example 4] In a flask equipped with a stirring device, a nitrogen gas introduction tube, a thermometer, and a reflux cooling tube, 50 parts by weight of methacrylate, bis[4- 10 parts by weight of {ethyl-2-(hydroxyethyl)aminocarbonyl}-benzyl]trithiocarbonate, the contents of the flask were heated to 80° C. while introducing nitrogen gas into the flask. Next, 0.03 parts by weight of AIBN that was sufficiently nitrogen-substituted was added to the flask while stirring, and heating and cooling were performed for 2 hours so that the temperature of the contents in the flask could be maintained at 80°C. The 105°C nonvolatile content of the acrylic polymer obtained in this manner was 99.5%. Next, after raising the temperature of the content in the flask to 90° C., 50 parts by weight of butyl acrylate was added dropwise over 1 hour. Then, heating and cooling were performed for 3 hours so that the temperature of the content in the flask could be maintained at 90° C., and finally 25 parts by weight of ethyl acetate was added.

The (meth)acrylic triblock polymer MBM1 is obtained in the manner described. The properties of the triblock polymer MBM1 are shown in Table 3 below.

[table 3]

[Synthesis Examples 5 to 8] In the same manner as in Synthesis Example 4, except that the weight average molecular weight of the finally obtained polymer was as described in Table 3, (meth)acrylic triblock polymerization was synthesized, respectively. Material MBM2 ~ 5. [Synthesis Example 9] A (meth)acrylic-based system was synthesized in the same manner as in Synthesis Example 4, except that the order of introducing the monomers was changed and the weight average molecular weight of the finally obtained polymer was as described in Table 3. Triblock polymer BMB1.

[Synthesis Example 10] Bis[4-{ethyl-2-(hydroxyethyl)aminocarbonyl}-benzyl]trithiocarbonate was changed to N-methyl-N-phenyldithiocyanocarbamate A (meth)acrylic-based diblock polymer M-B was synthesized in the same manner as in Synthesis Example 4, except for the methyl ester. The properties of the diblock polymer M-B are shown in Table 3 above.

[Examples 1 to 10 and Comparative Examples 1 to 6] The (meth)acrylic polymers obtained in Synthesis Examples 1 to 10 and Coronate L (manufactured by Tosoh Co., Ltd.) as an isocyanate-based crosslinking agent were used as The combinations and ratios described in the following Tables 4 and 5 were mixed to obtain an adhesive composition.

For each obtained adhesive composition, the thickness of the adhesive layer after drying was adjusted so that the thickness of the adhesive layer after drying was adjusted as shown in Tables 4 and 5, and it was applied to a light release film, and after drying, it was transferred to PET with a thickness of 25 μm. Membrane (Lumirror, manufactured by Toray Corporation). An adhesive sheet is produced by forming an adhesive layer on the base material in this manner. The thickness of the adhesive layer is shown in Table 4 and Table 5 together.

[Table 4]

[table 5]

[Gel Fraction] 0.1 g of the adhesive layer obtained in Examples etc. was placed in a sample vial, 30 cc of ethyl acetate was added, and the adhesive layer was infiltrated for 24 hours, and then the contents of the sample vial were used A 200-mesh stainless steel wire mesh was filtered and separated, and the weight of the residue after drying on the wire mesh at 100° C. for 2 hours was taken as the dry weight. Using the obtained weight measurement value, the gel fraction was calculated according to the following formula. The results are shown in Table 4 and Table 5 together.

Gel fraction (%) = 100 × (dry weight/adhesive layer weight taken)

[Adhesive Strength] Using the adhesive sheet produced by the above procedure, the exposed adhesive layer was press-bonded (attached) to the SUS plate under the conditions of 25° C./50% RH using a 2 kg roller. After standing for 20 minutes after attaching, the adhesive sheet was peeled off from the SUS plate at a peeling speed of 300 mm/min under the conditions of 25°C/50%RH and a peeling angle of 180°, and the peeling of the adhesive layer of the adhesive sheet was measured. force (adhesion). The results are shown in Table 4 and Table 5 together.

[Retaining force] The holding force is carried out according to JIS Z 1541. The adhesive sheet is cut into a width of 20 mm, and attached to a stainless steel plate so that the area of 20 × 20 mm is in contact with the stainless steel plate, and 1 Kg of load, and observe whether it falls off when left for 1 hour. The results are shown in Table 4 and Table 5 together.

[Constant Load Peeling Resistance] The exposed adhesive layer was bonded to the lower surface side of the stainless steel substrate arranged so that the front and back surfaces were parallel to the horizontal direction. Next, the test piece attached to the stainless steel substrate was left to stand for 60 minutes in a state where a load was applied to the lower side in the vertical direction, and the peeling distance (mm) in the longitudinal direction of the test piece at this time was measured. or the time (min) until the drop. The load was set to 200 g when the measurement temperature was 40°C, and was set to 100 g at 80°C. The results are shown in Table 4 and Table 5 together.

[Analysis of Results] In Examples 1 to 10, by using a (meth)acrylic random polymer containing a (meth)acrylic random polymer and having a weight average molecular weight (Mw) of 3,000 to 30,000 as measured by gel permeation chromatography Base) acrylic triblock polymer adhesive composition, can achieve excellent adhesion, retention and constant load peel resistance. On the other hand, in Comparative Examples 1 to 6, since adhesive compositions containing no (meth)acrylic triblock polymer having a weight average molecular weight (Mw) of 3,000 to 30,000 were used, the results were adhesive force or At least one of the constant load peel resistance is not excellent. Therefore, it can be clearly seen that the adhesive compositions prepared in Examples 1 to 10 are superior to the adhesive compositions prepared in Comparative Examples 1 to 6.

none

none

Claims (10)

An adhesive composition comprising a (meth)acrylic random polymer and a (meth)acrylic triblock polymer, the (meth)acrylic triblock polymer being subjected to gel permeation chromatography The measured weight average molecular weight (Mw) was 3,000 to 10,000. The adhesive composition according to claim 1, wherein the compounding amount of the (meth)acrylic triblock polymer is in the range of 100 parts by mass of the (meth)acrylic random polymer Within the range of 1 to 49 parts by mass. The adhesive composition according to claim 1 or claim 2, wherein the (meth)acrylic triblock polymer has a structure formed by block [A] and block [B] from [A] The structure represented by -[B]-[A]. The adhesive composition according to item 1 or item 2 of the claimed scope further comprises an isocyanate-based crosslinking agent. The adhesive composition according to item 1 or item 2 of the claimed scope is used for optical applications. An adhesive formed from the adhesive composition described in any one of items 1 to 5 of the patent application scope. An adhesive sheet, comprising: a base material; and an adhesive layer, formed on at least one side of the base material by using the adhesive composition described in any one of items 1 to 5 of the patent application scope. The adhesive sheet according to claim 7, wherein the thickness of the adhesive layer is 15 μm or less. An optical component comprising an adhesive layer formed of the adhesive composition according to any one of claims 1 to 5 of the application scope. The optical component according to claim 9, wherein the thickness of the adhesive layer is 15 μm or less.