TW201540796A - Adhesive composition and surface protection film - Google Patents

Abstract

The present invention provides an adhesive composition that has antistatic performance, that has excellent adhesive strength balance at a slow peel rate and at a fast peel rate, that has a long pot life, and that has excellent durability performance and reworking performance. The adhesive composition of the present invention, with respect to 100 parts by weight of a copolymer of (A) at least one (meth)acrylic acid ester monomer having a C4 to C18 alkyl group and, as a copolymerizable monomer, (B) a hydroxyl group-containing copolymerizable monomer, includes 0.1 to 10 parts by weight of (C) a bifunctional or higher isocyanate compound, 0.001 to 0.5 parts by weight of (D) a cross-linking promoting agent of a metal chelate compound, 0.1 to 200 parts by weight of (E) a keto-enol tautomer compound, and 0.05 to 5 parts by weight of an ionic compound having a melting point of 25 to 50 DEG C as (F) an antistatic agent, wherein the parts by weight ratio of (E)/(D) is 70 to 700.

Description

Adhesive composition and surface protection film

The present invention relates to an adhesive composition and a surface protective film. More specifically, the present invention relates to a surface protective film for a polarizing plate which has antistatic properties, excellent balance of adhesion at a low peeling speed and a high peeling speed, long shelf life, and excellent durability and reworkability. Adhesive compositions and surface protective films are used.

The adhesive for optical use is preferably a copolymer obtained by copolymerizing an acrylic monomer having a hydroxyl group, a carboxyl group or the like as a functional group, using a (meth)acrylic acid alkyl ester as a main component from the viewpoint of excellent transparency. The acrylic adhesive is composed. Further, an adhesive which appropriately adjusts various physical properties such as adhesion is required. In particular, in order to be suitable for a manufacturing process in a factory, an adhesive for a surface protective film or the like is required to have excellent adhesion balance at a low peeling speed and a high peeling speed suitable for bonding by an automatic bonding device. . Further, in addition to the balance of adhesion, an adhesive having a long shelf life, excellent durability, reworkability, and antistatic property is required.

For the various physical properties of the adhesive, an isocyanate crosslinking agent, an epoxy crosslinking agent, or the like which reacts with a functional group such as a hydroxyl group or a carboxyl group contained in an acrylic pressure-sensitive adhesive composed of a copolymer can be used. To carry out the crosslinking reaction, thereby adjusting the adhesion, cohesion and the like.

Conventionally, as a crosslinking agent for an acrylic adhesive, an isocyanate crosslinking agent is usually used. Further, in the crosslinking reaction using an isocyanate crosslinking agent, a metal chelate compound is often used as a catalyst for promoting the crosslinking reaction.

In general, from the viewpoint of excellent reaction rate of the crosslinking reaction, an organotin compound, that is, dibutyltin dilaurate, is used as a catalyst for the crosslinking reaction, but since dibutyltin compounds exhibit harmful toxicity, they are currently being avoided. use.

Therefore, there is a need for a crosslinking catalyst which is excellent in a reaction rate which can be used in combination with an isocyanate crosslinking agent, can replace a dibutyltin compound, and is inexpensive and cross-linking, but it is difficult to develop.

In view of the above, Patent Document 1 discloses that, as a crosslinking catalyst which can be used in combination with an isocyanate crosslinking agent, an iron chelate compound is preferable among metal chelate compounds; and because of tris(acetonitrile) group coordination Iron is particularly preferred because it has excellent catalytic activity.

However, the acrylic pressure-sensitive adhesive composition containing a crosslinking catalyst slowly undergoes a crosslinking reaction even during storage at normal temperature. Therefore, in the industrial production of the adhesive, in order to stop the crosslinking reaction in the period from the start of the crosslinking of the raw material of the adhesive composition to the initiation of the crosslinking reaction, a crosslinking catalyst and a reaction inhibitor are usually used in combination.

Regarding the use of the crosslinking catalyst in combination with a reaction inhibitor, Patent Document 2 discloses a method for producing a polyurethane, which comprises a mixture comprising at least one metal acetoacetone and acetamidine acetone and the aforementioned metal acetamidine. A reaction polyurethane mixture of a catalyst system having a weight ratio of acetone to the aforementioned acetamidine acetone of 2:1.

In the adhesive composition described in Patent Document 1, the addition amount of a metal compound (crosslinking catalyst) to a copolymer containing a (meth) acrylate as a constituent monomer unit and having a hydroxyl group and a carboxyl group has been proposed. However, the amount of the crosslinking inhibitor added is not described. In addition, in the method of suppressing the viscosity increase rate after the crosslinking agent is added to the adhesive composition, a method of using a reaction inhibitor, a method of adding a solvent for suppressing an increase in viscosity, and a method are used. A method of blocking a (block) crosslinking agent such as a blocked isocyanate or the like, but is not specifically described.

Further, Patent Document 2 discloses a method for producing a polyurethane in which a catalyst system is used which does not cause early curing and is excellent even if a metal acetoacetone catalyst such as iron or copper which is highly active at a low temperature is used. The stability and good catalytic activity of the metal acetamidine acetone and acetamidine acetone.

However, in the method described in Patent Document 2, the weight ratio of the metal acetamidine acetone to the acetamidine acetone is 2:1. However, when the compounding ratio is used in the production process of the acrylic pressure-sensitive adhesive, the compounding ratio cannot be used. The crosslinking reaction is temporarily stopped.

Prior art literature

Patent literature

Patent Document 1: Japanese Patent Publication No. 2011-001440

Patent Document 2: Japanese Laid-Open Patent Publication No. 2008-285681

Problem to be solved by the invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide an antistatic property without using an organotin compound, an excellent balance of adhesion at a low peeling speed and a high peeling speed, and a long shelf life. An adhesive composition for a surface protective film of a polarizing plate excellent in durability and reworkability, and a surface protective film.

Technical means of solving problems

In order to solve the above problems, the present invention provides an adhesive composition.

The adhesive composition comprises: (A) at least one of (C) a C4 to C18 (meth) acrylate monomer having an alkyl group and (B) a hydroxyl group-containing copolymerizable monomer as a copolymerizable monomer group 100 parts by weight of the copolymer of the body; (C) 0.1 to 10 parts by weight of the difunctional or higher isocyanate compound; (D) 0.001 to 0.5 part by weight of the crosslinking catalyst of the metal chelate; (E) keto-enol tautomerization 0.1 to 200 parts by weight of the compound; and 0.05 to 5 parts by weight of the ionic compound having a melting point of 25 to 50 ° C as the (F) antistatic agent, and a ratio by weight of (E)/(D) of 70 to 700.

Further, it is preferred that the (B) hydroxyl group-containing copolymerizable monomer is selected from the group consisting of 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Ester, 2-hydroxyethyl (meth)acrylate, N-hydroxy(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, and N-hydroxyethyl(meth)acrylamide At least one or more of the compound groups of the composition.

In addition, the difunctional or higher isocyanate compound (C) is preferably a compound obtained by reacting a diisocyanate compound with a diol compound as a difunctional isocyanate compound which is an acyclic aliphatic isocyanate compound. The diisocyanate compound is an aliphatic diisocyanate, preferably selected from the group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethyl hexamethylene diisocyanate, and an amine. One of a group of compounds consisting of acid diisocyanate. Further, the diol compound is preferably selected from the group consisting of 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, and 2-methyl-2-propyl-1. , 3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol monohydroxynew One of a group of compounds consisting of valerate, polyethylene glycol, and polypropylene glycol.

Further, the (C) difunctional or higher isocyanate compound is preferably an isocyanuric acid selected from the isocyanurate or isophorone diisocyanate compound of a hexamethylene diisocyanate compound as a trifunctional isocyanate compound. An acid ester, an adduct of a hexamethylene diisocyanate compound, an adduct of an isophorone diisocyanate compound, a biuret of a hexamethylene diisocyanate compound, and a biuret of an isophorone diisocyanate compound An isocyanurate of a toluene diisocyanate compound, an isocyanurate of a benzodimethyl diisocyanate compound, an isocyanurate of a hydrogenated dimethylated diisocyanate compound, an adduct of a toluene diisocyanate compound, At least one or more of the compound group consisting of an adduct of a benzenedimethyl diisocyanate compound and an adduct of a hydrogenated dimethyl diisocyanate compound.

Further, the crosslinking catalyst in the pressure-sensitive adhesive composition is preferably at least one selected from the group consisting of aluminum chelate compounds, titanium chelate compounds, and iron chelate compounds.

Further, it is preferable that the antistatic agent (F) is an ionic compound containing 0.05 to 5.0 parts by weight and having a melting point of 25 to 50 ° C with respect to 100 parts by weight of the copolymer, and/or a copolymerization amount in the copolymer An ionic compound containing 0.1 to 5.0% by weight and containing an acrylonitrile group.

Preferably, the copolymer as the other copolymerizable monomer group includes at least one of a carboxyl group-containing monomer, a hydroxyl group-free nitrogen-containing vinyl monomer, and a polyalkylene glycol mono(meth)acrylate monomer. And/or as an additive include a polyether siloxane compound and other general antioxidants and the like.

Further, it is preferable that the adhesive layer obtained by crosslinking the above-mentioned adhesive composition has an adhesive force at a low peeling speed of 0.3 m/min of 0.05 to 0.1 N/25 mm, and an adhesive force at a high peeling speed of 30 m/min. 1.0N/25mm or less.

Further, it is preferable that the adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition has a surface resistivity of 9.0×10 ⁺¹¹ Ω/□ or less and a peeling static voltage of ±0 to 0.5 kV.

Further, the present invention provides an adhesive film obtained by forming an adhesive layer on one surface or both surfaces of a resin film, wherein the adhesive layer is obtained by crosslinking the above-mentioned adhesive composition.

Further, the present invention provides a surface protective film which is formed by forming an adhesive layer on one side of a resin film, wherein the adhesive layer is obtained by crosslinking the above-mentioned adhesive composition, wherein the adhesive is adhered by a ball pen. After the agent layer was drawn on the surface protective film, the contamination was not transferred to the adherend.

Further, the surface protective film of the present invention can be used as a surface protection of a polarizing plate.

Further, in the surface protective film of the present invention, it is preferred that the antistatic and antifouling treatment be performed on the surface of the resin film opposite to the side on which the adhesive layer is formed.

efficacy

According to the present invention, it is possible to satisfy all the properties required for the adhesive layer of the surface protective film which cannot be solved in the prior art without using an organotin compound, and it is possible to obtain excellent antistatic properties and prevent adhesive residue. The phenomenon occurs. Specifically, not only the excellent antistatic property can be maintained, but also the amount of the antistatic agent added can be reduced, and the performance of preventing the adhesive residue from remaining can be improved.

Hereinafter, the present invention will be described based on preferred embodiments.

The adhesive composition of the present invention comprises: (A) at least one of (C) a C4-C18 (meth) acrylate monomer having an alkyl group and (B) a hydroxyl group-containing group as a copolymerizable monomer group 100 parts by weight of the copolymer of the comonomer; (C) 0.1 to 10 parts by weight of the difunctional or higher isocyanate compound; (D) 0.001 to 0.5 part by weight of the crosslinking catalyst of the metal chelate; (E) keto-enol 0.1 to 200 parts by weight of the isomer compound; and 0.05 to 5 parts by weight of the ionic compound having a melting point of 25 to 50 ° C as the (F) antistatic agent, and the ratio by weight of (E)/(D) is 70 ~700.

The aforementioned copolymer, as another copolymerizable monomer group, may include at least one of a carboxyl group-containing monomer, a hydroxyl group-free nitrogen-containing vinyl monomer, and a polyalkylene glycol mono(meth)acrylate monomer. the above.

The antistatic agent (F) may be an ionic compound containing 0.05 to 5.0 parts by weight and having a melting point of 25 to 50 ° C with respect to 100 parts by weight of the copolymer, and/or a copolymerization amount of 0.1 in the copolymer. ～5.0% by weight of an ionic compound containing an acrylonitrile group.

Further, the adhesive composition of the present invention may include, as an additive, a polyether siloxane compound and other general antioxidants.

Examples of the (meth) acrylate monomer having a CA to C18 carbon atom as the (A) alkyl group include butyl (meth)acrylate, isobutyl (meth)acrylate, and (meth)acrylic acid. Amyl ester, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (A) Ethyl acrylate, isodecyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, (meth) acrylate Alkyl ester, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, cetyl (meth)acrylate, (a) Pentadecyl acrylate, octadecyl (meth) acrylate, myristyl (meth) acrylate, isotetradecyl (meth) acrylate, cetyl (meth) acrylate, Isohexadecyl (meth)acrylate, stearyl methacrylate and (meth) propylene Isostearyl acrylate.

The content of the (meth) acrylate monomer having a CA to C18 carbon number of the (A) alkyl group is preferably 50 to 98 parts by weight based on 100 parts by weight of the copolymer.

Examples of the (B) hydroxyl group-containing copolymerizable monomer include 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and ( Hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl methacrylate; N-hydroxy(meth) acrylamide, N-hydroxymethyl (meth) acrylamide, and N-hydroxyethyl A (meth) acrylamide containing a hydroxyl group, such as a (meth) acrylamide.

Preferably, the hydroxyl group-containing copolymerizable monomer is selected from the group consisting of 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, (methyl) a group of compounds consisting of 2-hydroxyethyl acrylate, N-hydroxy(meth) acrylamide, N-methylol (meth) acrylamide, and N-hydroxyethyl (meth) acrylamide At least one of the above.

The content of the (B) hydroxyl group-containing copolymerizable monomer is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the copolymer.

For the aforementioned copolymer, it can also be used as a group of other copolymerizable monomers, including a carboxyl group-containing monomer, a hydroxyl group-free nitrogen-containing vinyl monomer, and a polyalkylene glycol mono(meth)acrylate single. At least one or more of the bodies.

Preferably, the carboxyl group-containing monomer is selected from the group consisting of (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, 2-(methyl)propenyloxyethylhexahydro Phthalic acid, 2-(methyl)propenyloxypropyl hexahydrophthalic acid, 2-(meth)acryloxyethyl phthalate, 2-(methyl) propylene oxime Ethyl succinic acid, 2-(methyl) propylene oxiranyl ethyl maleic acid, carboxy polycaprolactone mono (meth) acrylate, and 2-(methyl) propylene oxiranyl ethyl tetrahydroortho At least one or more of the compound groups consisting of phthalic acid.

When the copolymer described above as the other copolymerizable monomer group includes a carboxyl group-containing monomer, the content of the carboxyl group-containing monomer is preferably 0.1 to 1.0 part by weight based on 100 parts by weight of the copolymer. The aforementioned copolymer may also be free of the aforementioned carboxyl group-containing monomer.

The polyalkylene glycol mono(meth)acrylate monomer may be a compound in which one of a plurality of hydroxyl groups of the polyalkylene glycol is esterified to a (meth)acrylate. . Since the (meth) acrylate group is a polymerizable group, it can be copolymerized with the copolymer of the main component. The other hydroxyl group may be in the state of OH, may be an alkyl ether such as methyl ether or diethyl ether, or may be a saturated carboxylic acid ester such as acetate.

The alkylene group which the polyalkylene glycol has may be a vinyl group, a propenyl group or a butenyl group, but is not limited thereto. The polyalkylene glycol may be a copolymer of two or more polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Examples of the copolymer of polyalkylene glycol include polyethylene glycol-polypropylene glycol, polyethylene glycol-polybutylene glycol, polypropylene glycol-polybutylene glycol, and polyethylene glycol-polypropylene glycol-polybutylene. The diol or the like may be a block copolymer or a random copolymer.

It is preferable that the average number of repetitions of the alkylene oxide constituting the polyalkylene glycol chain in the polyalkylene glycol mono(meth)acrylate monomer is from 3 to 14. The "average number of repeats of alkylene oxide" means the alkylene oxide in the "polyalkylene glycol chain" portion contained in the molecular structure of the polyalkylene glycol mono(meth)acrylate monomer. The average number of unit repetitions.

The polyalkylene glycol mono(meth)acrylate monomer is preferably selected from the group consisting of polyalkylene glycol mono(meth)acrylates and methoxypolyalkylene glycol (meth)acrylic acid. At least one of an ester and an ethoxylated polyalkylene glycol (meth) acrylate.

More specifically, polyethylene glycol mono- (meth) acrylate, polypropylene glycol mono (meth) acrylate, polybutylene glycol mono (meth) acrylate, polyethylene glycol - polypropylene glycol mono- (meth) acrylate, polyethylene glycol - polybutylene glycol - mono (meth) acrylate, polypropylene glycol - polybutylene glycol - mono (meth) acrylate, polyethylene glycol - polypropylene glycol - polybutylene glycol - mono (meth) acrylate; methoxy polyethylene glycol - (meth) acrylate, methoxy polypropylene glycol - (meth) acrylate, methoxy poly butyl Glycol-(meth) acrylate, methoxy-polyethylene glycol-polypropylene glycol-(meth) acrylate, methoxy-polyethylene glycol-polybutylene glycol-(meth) acrylate, Methoxy-polypropylene glycol-polybutylene glycol-(meth)acrylate, methoxy-polyethylene glycol-polypropylene glycol-polybutylene glycol-(meth)acrylate; ethoxypolyethylene glycol -(Meth)acrylate, ethoxypolypropylene glycol-(meth)acrylate, ethoxylated polybutylene glycol-(meth)acrylate, ethoxy-polyethylene glycol-polypropylene glycol-(A Acrylate, ethoxy-polyethylene glycol-polybutylene glycol-(meth) acrylate, ethoxy-polypropylene glycol-polybutylene glycol-(meth) acrylate, ethoxy-poly Ethylene glycol-polypropylene glycol-polybutylene glycol-(meth)acrylate or the like.

The content of the polyalkylene glycol mono(meth)acrylate monomer is preferably from 0 to 50 parts by weight based on 100 parts by weight of the copolymer. The aforementioned copolymer may not contain the aforementioned polyalkylene glycol mono(meth)acrylate monomer.

Examples of the vinyl monomer containing no hydroxyl group and containing nitrogen include a vinyl monomer containing a guanamine bond, a vinyl monomer containing an amine group, a vinyl monomer having a nitrogen-containing heterocyclic structure, and the like. . More specifically, N-vinyl-2-pyrrolidone, N-vinylpyrrolidone, methylvinylpyrrolidone, N-vinylpyridine, N-vinylacridone, N-vinylpyrimidine, N-vinylpyridazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, and N a cyclic nitrogen vinyl compound having an N-vinyl substituted heterocyclic ring structure such as vinyl dodecanoin; N-(meth)acryl hydrazinomorpholine, N-(methyl) acrylonitrile fluorene Pyrazine, N-(methyl) acrylonitrile aziridine, N-(methyl) propylene decylpyridinium, N-(methyl) propylene decyl pyrrolidine, N-(methyl) propylene fluorenyl a heterocyclic structure having an N-(meth)acrylinyl group-substituted heterocyclic structure such as acridine, N-(methyl)acrylonitrile-azepane and N-(methyl)propenylazepane Cyclic nitrogen-vinyl compound; N-cyclohexylmaleimide and N-phenylmaleimide, etc., cyclic nitrogen-containing ethylene having a heterocyclic structure containing a nitrogen atom and a vinyl-based unsaturated bond in the ring. Base compound; Alkenylamine, N-methyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and unsubstituted or monoalkyl such as N-tert-butyl(meth)acrylamide Substituted (meth) acrylamide; N,N-dimethyl(meth) acrylamide, N,N-diethyl(meth) acrylamide, N,N-dipropyl acrylamide , N,N-diisopropyl(meth)acrylamide, N,N-dibutyl(meth)acrylamide, N-ethyl-N-methyl(meth)acrylamide, N -Methyl-N-propyl (meth) acrylamide and dialkyl substituted (meth) acrylamide such as N-methyl-N-isopropyl (meth) acrylamide; N, N- Dimethylaminomethyl (meth) acrylate, N,N-dimethylaminoethyl (meth) acrylate, N,N-dimethylaminopropyl (meth) acrylate, N,N-Dimethylaminoisopropyl(meth)acrylate, N,N-dimethylaminobutyl(meth)acrylate, N,N-diethylaminomethyl (A) Acrylate, N,N-diethylaminoethyl (meth) acrylate, N-ethyl-N-methylaminoethyl (meth) acrylate, N-methyl-N -propylaminoethyl (meth) acrylate, N-methyl-N-isopropylaminoethyl (meth) acrylate, N,N-dibutylaminoethyl (methyl) Dialkylamino (meth) acrylate such as acrylate and tert-butylaminoethyl (meth) acrylate; N,N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide, N,N-dipropylaminopropyl (meth) acrylamide, N,N-diisopropylaminopropyl (A Acrylamide, N-ethyl-N-methylaminopropyl (meth) acrylamide, N-methyl-N-propylaminopropyl (meth) acrylamide, and N- N,N-dialkyl substituted aminopropyl (meth) acrylamide such as methyl-N-isopropylaminopropyl (meth) acrylamide; N-vinylformamide, N - vinyl acetamide and N-vinyl carboxylic acid amide such as N-vinyl-N-methylacetamide; N-methoxymethyl (meth) acrylamide, N-ethoxy Ethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, diacetone acrylamide, and N, N-methylene bis (meth) propylene Amine (meth) acrylamide-based; (meth) acrylonitrile, unsaturated carboxylic acid nitriles and the like.

The content of the above-mentioned vinyl group containing no hydroxyl group and containing nitrogen is preferably 0 to 20 parts by weight based on 100 parts by weight of the copolymer. The aforementioned copolymer may not contain the above-mentioned vinyl monomer containing no hydroxyl group and containing nitrogen.

The (C) difunctional or higher isocyanate compound may be at least one or two or more selected from the group consisting of polyisocyanate compounds having at least two or more isocyanate (NCO) groups in one molecule. The polyisocyanate compound includes classifications such as aliphatic isocyanate, aromatic isocyanate, acyclic isocyanate, and alicyclic isocyanate, and the present invention may be any of them. Specific examples of the polyisocyanate compound include aliphatic isocyanate compounds such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and trimethylhexamethylene diisocyanate (TMDI). Diphenylmethane diisocyanate (MDI), benzodimethyl diisocyanate (XDI), hydrogenated dimethyl diisocyanate (H6XDI), dimethyl diphenylene diisocyanate (TODI), and toluene diisocyanate (TDI) An aromatic isocyanate compound.

Examples of the trifunctional or higher isocyanate compound include a biuret modified product or a isocyanurate modified product of a difunctional isocyanate compound (a compound having two NCO groups in one molecule), and a trihydroxyl group. An adduct (polyol modified product) of a trivalent or higher polyvalent alcohol (a compound having at least three or more OH groups in one molecule) such as a propane (TMP) or glycerin.

As the (C) difunctional or higher isocyanate compound, only the (C-1) trifunctional isocyanate compound or the (C-2) difunctional isocyanate compound can be used. Further, a (C-1) trifunctional isocyanate compound and a (C-2) difunctional isocyanate compound may be used in combination.

Further, the (C-1) trifunctional isocyanate compound used in the present invention preferably includes at least one selected from the group consisting of (C-1-1) first aliphatic isocyanate compounds and selected from (C-1- 2) at least one or more of the group of the second aromatic isocyanate compounds, wherein the (C-1-1) first aliphatic isocyanate compound group is an isocyanurate of a hexamethylene diisocyanate compound An isocyanurate of an isophorone diisocyanate compound, an adduct of a hexamethylene diisocyanate compound, an adduct of an isophorone diisocyanate compound, and a biuret of a hexamethylene diisocyanate compound And a biuret composed of an isophorone diisocyanate compound; the (C-1-2) second aromatic isocyanate compound group is an isocyanurate or a benzene dimethyl group derived from a toluene diisocyanate compound. An isocyanurate of an isocyanate compound, an isocyanurate of a hydrogenated dimethylated diisocyanate compound, an adduct of a toluene diisocyanate compound, and an adduct of a phthalic diisocyanate compound, Adducts of hydrogenated xylylene diisocyanate compound composed. Preferably, the (C-1-1) first aliphatic isocyanate compound group and the (C-1-2) second aromatic isocyanate compound group are used in combination. In the present invention, as the (C-1) trifunctional isocyanate compound, at least one selected from the group consisting of (C-1-1) first aliphatic isocyanate compounds and selected from (C-1-2) are used in combination. At least one or more of the second aromatic isocyanate compound groups can further improve the balance of the adhesion in the low-speed peeling region and the high-speed peeling region.

Further, it is preferable that the (C-1) trifunctional isocyanate compound includes at least one selected from the group consisting of the aforementioned (C-1-1) first aliphatic isocyanate compound group and is selected from the aforementioned (C-1-2) second. At least one or more of the aromatic isocyanate compound groups, and the total content of the (C) trifunctional or higher isocyanate compound is 0.5 to 5.0 parts by weight based on 100 parts by weight of the copolymer. Further, as at least one or more selected from the group consisting of (C-1-1) a first aliphatic isocyanate compound group and at least one selected from the group consisting of (C-1-2) second aromatic isocyanate compound groups The ratio is preferably (C-1-1) by weight ratio: (C-1-2) is in the range of 10%: 90% to 90%: 10%.

Further, the (C-2) difunctional isocyanate compound used in the present invention is preferably an acyclic aliphatic isocyanate compound, and is a compound formed by reacting a diisocyanate compound with a diol compound.

For example, when the formula "O=C=NXN=C=O" (where X is a divalent group), the diisocyanate compound is represented, and the formula "HO-Y-OH" (where Y is 2 valence) In the case of the diol compound, a compound which is formed by reacting a diisocyanate compound with a diol compound, for example, may be a compound represented by the following formula Z.

[Formula Z]

O=C=NX-(NH-CO-OYO-CO-NH-X) _n -N=C=O

Here, n is an integer of 0 or more. When n is 0, the general formula Z is expressed as "O=C=N-X-N=C=O". The difunctional acyclic aliphatic isocyanate compound may include a compound of the formula Z in which n is 0 (a diisocyanate compound which is not reacted with respect to the diol compound), and a compound in which n is an integer of 1 or more is preferable as an essential component. The difunctional acyclic aliphatic isocyanate compound may also be a mixture of a plurality of compounds of the formula Z in which n is not the same.

The diisocyanate compound represented by the formula "O=C=N-X-N=C=O" is an aliphatic diisocyanate. Preferably, X is an acyclic aliphatic divalent group. The aliphatic diisocyanate is preferably selected from the group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and isocyanuric acid diisocyanate. One or two or more of the compound groups composed.

The diol compound represented by the formula "HO-Y-OH" is an aliphatic diol. Preferably, Y is an acyclic aliphatic divalent group. The diol compound is preferably selected from the group consisting of 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, and 2-methyl-2-propyl-1. 3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol monohydroxynepenta One or more of the compound group consisting of an acid ester, polyethylene glycol, and polypropylene glycol.

The weight ratio (C-1/C-2) of the (C-1) trifunctional isocyanate compound to the (C-2) difunctional isocyanate compound is preferably from 1 to 90. The (C) difunctional or higher isocyanate compound is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the copolymer.

When the polyisocyanate compound is used as the crosslinking agent, the crosslinking catalyst of the (D) metal chelate compound may be a substance that functions as a catalyst to react with the crosslinking agent (crosslinking reaction) of the copolymer and the crosslinking agent. Examples thereof include an amine compound such as a tertiary amine, a metal chelate compound, an organotin compound, an organic lead compound, and an organic metal compound such as an organic zinc compound. A metal chelate compound is employed as the crosslinking catalyst in the present invention.

The metal chelate compound is a compound in which one or more multidentate ligands L are bonded to a central metal atom M. The metal chelate may or may not have one or more monodentate ligands X bonded to the metal atom M. For example, when the general formula of the metal chelate compound having one metal atom M is represented by M(L) _m (X) _n , m ≥ 1, n ≥ 0. When m is 2 or more, m of L may be the same ligand or a different ligand. When n is 2 or more, n of X may be the same ligand or a different ligand.

Examples of the metal atom M include iron (Fe), nickel (Ni), manganese (Mn), chromium (Cr), vanadium (V), titanium (Ti), ruthenium (Ru), zinc (Zn), and aluminum ( Al), zirconium (Zr), tin (Sn), and the like.

Examples of the polydentate ligand L include methyl ethyl acetate, ethyl acetate, octyl acetate, ethyl acetoacetate, lauryl acetate, and stearyl acetate. --ketoester; β-diketone such as acetamidine acetone (alias: 2,4-pentanedione), 2,4-hexanedione, and benzamidine acetone. They are keto-enol tautomer compounds, and in the polydentate ligand L, they may also be enolates (for example, acetoacetate) in which an enol is deprotonated.

Examples of the monodentate ligand X include a halogen atom such as a chlorine atom and a bromine atom; a pentamidine group, a hexyl group, a 2-ethylhexyl group, a octyl group, a fluorenyl group, a fluorenyl group, and a fluorenyl group; An alkoxy group such as a stearyl group; an alkoxy group such as a methoxy group, an ethoxy group, a n-propoxy group, an isopropoxy group or a butoxy group; and the like.

Specific examples of the metal chelate compound include tris(2,4-pentanedione)iron (III) (Tris(2,4-pentanedionato)iron(III)), triethylsulfonium iron, triethyl ethoxide醯Acetone acetonide, triethyl hydrazine acetonide, diethyl acetonide zinc, triethyl acetonide aluminum, tetraethyl hydrazine zirconium, tris(2,4-hexanedione) iron (III), bis (2,4-hexyl) Diketone) zinc, tris(2,4-hexanedione)titanium, tris(2,4-hexanedione)aluminum, and tetrakis(2,4-hexanedione)zirconium, and the like.

Examples of the organotin compound include a dialkyl tin oxide, a fatty acid salt of a dialkyl tin, and a fatty acid salt of stannous. In the past, dibutyltin compounds have been used in most cases, but in recent years, the toxicity problem of organotin compounds has been pointed out, and in particular, tributyltin (TBT) contained in dibutyltin compounds is also considered as an endocrine disruptor. From the viewpoint of safety, a long-chain alkyl tin compound such as a dioctyltin compound is preferred. Specific examples of the organotin compound include dioctyltin oxide and dioctyltin dilaurate. Although it is also possible to use the Sn compound temporarily, in view of the tendency to use a more safe substance in the future, it is preferred to use a metal chelate compound of Al, Ti, Fe or the like which is safer than Sn.

The metal chelate compound in the adhesive composition of the present invention preferably contains at least one selected from the group consisting of aluminum chelate compounds, titanium chelate compounds, and iron chelate compounds.

The content of the crosslinking catalyst of the (D) metal chelate compound is preferably 0.001 to 0.5 parts by weight based on 100 parts by weight of the copolymer.

Examples of the (E) keto-enol tautomer compound include methyl acetonitrile acetate, ethyl acetate, octyl acetate, ethyl acetoacetate, lauryl acetate, and acetamidine. a β-ketoester such as stearyl acetate; a β-diketone such as acetamidineacetone, 2,4-hexanedione or benzamidineacetone. In the adhesive composition using a polyisocyanate compound as a crosslinking agent, by blocking the isocyanate group of the crosslinking agent, it is possible to suppress excessive increase or gelation of the viscosity of the adhesive composition after the crosslinking agent is blended. The phenomenon can extend the shelf life of the adhesive composition.

The content of the (E) keto-enol tautomer compound is preferably from 0.1 to 200 parts by weight based on 100 parts by weight of the copolymer.

In contrast to the crosslinking catalyst of the (D) metal chelate compound, the (E) keto-enol tautomer compound has an effect of inhibiting crosslinking, and therefore, it is preferred to appropriately set the (E) keto-enol tautomer The ratio of the compound to the crosslinking catalyst of the (D) metal chelate. In order to prolong the shelf life of the adhesive composition and improve storage stability, the weight ratio (E)/(D) of the cross-linking catalyst of the (E) keto-enol tautomer compound/(D) metal chelate compound is preferred. ) is a high value. The value of (E)/(D) is preferably in the range of 70 to 700, more preferably 70 to 300, and most preferably 80 to 300.

Examples of the (F) antistatic agent include an antistatic agent contained in the adhesive composition and an antistatic agent copolymerized in the copolymer. The content of the (F) antistatic agent is preferably 0.05 to 5.0 parts by weight based on 100 parts by weight of the copolymer.

Preferably, the antistatic agent (F) is (F-1) an ionic compound having a melting point of 25 to 50 ° C and/or (F-2) an ionic compound containing an acrylonitrile group.

In the present invention, as the (F) antistatic agent, (F-1) an ionic compound having a melting point of 25 to 50 ° C is added to the copolymer, and/or (F-2) an ion containing an acrylonitrile group is added. The compound is copolymerized in the copolymer. It is presumed that since these (F) antistatic agents have a low melting point and a long-chain alkyl group, they have high affinity with an acrylic copolymer.

The (F-1) ionic compound having a melting point of 25 to 50 ° C is an ionic compound having a cation and an anion, and examples of the cation include a pyridinium cation, an imidazolium cation, a pyrimidine cation, and a pyrazolium cation. a pyridinium cation, a nitrogen-containing phosphonium cation such as an ammonium cation, or a phosphonium cation or a phosphonium cation, and the anion is hexafluorophosphate (PF ₆ ^— ), thiocyanate (SCN ^— ), alkylbenzenesulfonate (RC ₆ H). ₄ SO ₃ ^— ), perchlorate (ClO ₄ ^— ), tetrafluoroborate (BF ₄ ^— ), bis(fluorosulfonyl) ruthenium (FSI), bis(trifluoromethanesulfonyl)fluorene A compound of an inorganic or organic anion such as an imine root (TFSI) or a triflate (TF). It is preferably a solid at normal temperature (for example, 25 ° C), and a compound having a melting point of 25 to 50 ° C can be obtained by selecting the chain length of the alkyl group and the position and number of the substituent. The cation is preferably a quaternary nitrogen sulfonium cation, and examples thereof include a quaternary pyridinium cation such as 1-alkylpyridinium (having a substituent or a substituent at a carbon atom of 2 to 6), and 1,3-di A quaternary imidazolium cation such as an alkylimidazolium (a carbon atom at the 2, 4, or 5 positions may have a substituent or a substituent), or a quaternary ammonium cation such as a tetraalkylammonium.

The content of the (F-1) ionic compound having a melting point of 25 to 50 ° C is preferably 0.05 to 5 parts by weight based on 100 parts by weight of the copolymer.

The ionic compound containing an acryl fluorenyl group as (F-2) is an ionic compound having a cation and an anion, and the cation is a (meth) propylene decyloxyalkyltrialkylammonium (R ₃ N ^{+ )} -C _n H _2n -OCOCQ=CH ₂ , wherein Q=H or CH ₃ , R=alkyl), etc., a (meth)acryloyl group-containing cation; an anion is hexafluorophosphate (PF ₆ ^— ), Thiocyanate (SCN ^— ), organic sulfonate (RSO ₃ ^— ), perchlorate (ClO ₄ ^— ), tetrafluoroborate (BF ₄ ^— ), quinone imine containing F (R ^F ₂ N ^— ) A compound of an inorganic or organic anion. (PEI) containing a root of F (R ^F ₂ N ^-) of R & lt ^F, include trifluoromethanesulfonic acyl, sulfo pentafluoroethyl acyl group such as a perfluoroalkyl sulfonic acyl, sulfo-fluoro-acyl. As the F-containing quinone imine root, bis(fluorosulfonyl) ruthenium root [(FSO ₂ ) ₂ N ^— ], bis(trifluoromethanesulfonyl) fluorenylene root [(CF _{3 )} SO ₂ ) ₂ N ^— bis, bis-sulfonyl ruthenium iodide such as bis(pentafluoroethanesulfonyl) quinone imide [(C ₂ F ₅ SO ₂ ) ₂ N ^— ].

It is preferred that the (F-2) ionic compound containing an acrylonitrile group is copolymerized in the copolymer in an amount of from 0.1 to 5.0% by weight.

Specific examples of the (F) antistatic agent are not particularly limited, but specific examples of the (F-1) ionic compound having a melting point of 25 to 50 ° C include 1-octylpyridinium hexafluorophosphate. 1-mercaptopyridinium hexafluorophosphate, 2-methyl-1-dodecylpyridinium hexafluorophosphate, 1-octylpyridinium dodecylbenzenesulfonate, 1-dodecyl Pyridinium thiocyanate, 1-dodecylpyridinium dodecylbenzenesulfonate, 4-methyl-1-octylpyridinium hexafluorophosphate, quaternary ammonium salt of trifluoromethanesulfonic acid, etc. . Further, specific examples of the (F-2) ionic compound containing an acrylonitrile group include dimethylaminomethyl (meth) acrylate hexafluorophosphate methyl salt [(CH ₃ ) ₃ N ⁺ CH ₂ OCOCQ=CH ₂ •PF ₆ ^— , wherein Q=H or CH ₃ ], dimethylaminoethyl (meth) acrylate bis(trifluoromethanesulfonyl) fluorene imine methyl salt [ (CH ₃ ) ₃ N ⁺ (CH ₂ ) ₂ OCOCQ=CH ₂ •(CF ₃ SO ₂ ) ₂ N ^— , wherein Q=H or CH ₃ ], dimethylaminomethyl methacrylate bis (fluorine Sulfhydryl) quinone imine methyl salt [(CH ₃ ) ₃ N ⁺ CH ₂ OCOCQ=CH ₂ • (FSO ₂ ) ₂ N ^— , wherein Q=H or CH ₃ ], and the like.

The adhesive composition of the present invention may contain, as an additive, a polyether siloxane compound and other general antioxidants.

The above polyether-modified siloxane compound is a siloxane compound having a polyether group, and has a polyoxyl group-containing siloxane unit in addition to a usual siloxane unit (-SiR ¹ ₂ -O-) (-SiR ¹ (R ² O(R ³ O) _n R ⁴ )-O-). Here, R ¹ represents one or two or more alkyl groups or aryl groups, R ² and R ³ represent one or two or more alkylene groups, and R ⁴ represents one or two or more alkyl groups, fluorenyl groups and the like ( End base). The polyether group may, for example, be a polyoxyalkylene group such as a polyoxyethylene group ((C ₂ H ₄ O) _n ) or a polyoxypropylene group ((C ₃ H ₆ O) _n ).

Preferably, the polyether modified siloxane compound is a polyether modified siloxane compound having an HLB value of 7 to 15. Further, the content of the polyether-modified siloxane compound is preferably 0.01 to 1.0 part by weight, more preferably 0.1 to 0.5 part by weight, per 100 parts by weight of the copolymer.

HLB is a predetermined hydrophilic-lipophilic balance (ratio of hydrophilicity to lipophilicity) such as JIS K3211 (surfactant term).

The above polyether-modified oxoxane compound can be obtained, for example, by grafting an organic compound having an unsaturated bond and a polyoxyalkylene group to a polyorganosiloxane having a decyl group by a hydrogenation oximation reaction. The main chain is obtained. Specifically, a dimethyl methoxy oxane-methyl (polyoxyethylene) decane copolymer, dimethyl methoxy oxane-methyl (polyoxyethylene) decane-methyl (poly) A propylene oxide) siloxane copolymer, a dimethyl methoxy oxane-methyl (polyoxypropylene) siloxane copolymer, and the like.

By blending the above polyether-modified siloxane compound with the adhesive composition, the adhesion and reworkability of the adhesive can be improved. When the adhesive composition does not contain a polyether modified siloxane compound, the cost can be made lower.

Examples of the antioxidant include a hindered phenol antioxidant, a polyphenol compound, and a tocopherol compound. Among them, a tocopherol compound is preferred. Tocopherols are usually vitamin E and are also derived from natural chemicals. Therefore, the adverse effects on the human body are small, and the safety in use is high, which is conducive to protecting the environment. Further, since it is oil-soluble and liquid at normal temperature, it is excellent in compatibility with the adhesive composition and excellent in precipitation resistance. By blending the tocopherol compound as the antioxidant, the storage stability of the adhesive is improved, and thus the pot life of the adhesive composition to which the curing agent is blended is increased.

The tocopherol compound to be used in the present invention is preferably a compound containing a phenolic hydroxyl group in which the phenolic hydroxyl group of the tocopherol does not become an ester or the like, from the viewpoint of being used in the adhesive composition (not being subjected to metabolism as in the human body). For example, tocopherol and tocotrienol can be mentioned. It is known that there are differences between a natural type compound (d-body), a non-natural type compound (1-body), and an isomer (dl-body) of their equal amounts in tocopherols and tocotrienols. The natural compound (d-body) and the racemate (dl-body) are preferably used as food additives or the like, and therefore are preferable.

Specific examples of the tocopherol compound include d-α-tocopherol, dl-α-tocopherol, d-β-tocopherol, dl-β-tocopherol, and d-γ-tocopherol. Dl-γ-tocopherol, d-δ-tocopherol, dl-δ-tocopherol, d-α-tocotrienol, dl-α-tocotrienol, d-β-tocotrienol, dl- At least a compound group consisting of β-tocotrienol, d-γ-tocotrienol, dl-γ-tocotrienol, d-δ-tocotrienol, and dl-δ-tocotrienol One. It is also possible to use two or more tocopherol compounds in combination. As a food additive, it is called "mixed tocopherol" and is mainly composed of d-α-tocopherol, d-β-tocopherol, d-γ-tocopherol and d-δ-tocopherol. a mixture of ingredients; a substance called "tocotrienol", which is d-α-tocotrienol, d-β-tocotrienol, d-γ-tocotrienol, and d-δ-fertility A mixture of trienols as a main component.

When the adhesive composition of the present invention contains a tocopherol compound, the content of the tocopherol compound is preferably 0.01 to 5 parts by weight based on 100 parts by weight of the copolymer.

Further, as another component, a copolymerizable (meth)acrylic monomer, a (meth)acrylamide monomer, a dialkyl-substituted acrylamide monomer, which contains an alkylene oxide, may be appropriately blended. A known additive such as a surfactant, a curing catalyst, a plasticizer, a filler, a curing inhibitor, a processing aid, an anti-aging agent, and an antioxidant. These may be used alone or in combination of two or more.

The copolymer of the main component used in the adhesive composition of the present invention can be obtained by copolymerizing at least one of (C) a C1-C18 (meth) acrylate monomer having a CA-C18 alkyl group as a copolymerizable single The (B) hydroxyl group-containing copolymerizable monomer of the body group is copolymerized to be synthesized. The polymerization method of the copolymer is not particularly limited, and an appropriate polymerization method such as solution polymerization or emulsion polymerization can be used.

When (F-2) an acrylonitrile-containing ionic compound is used as the (F) antistatic agent, the copolymer of the main component used in the adhesive composition of the present invention can be obtained by the carbon atom of the (A) alkyl group. At least one of a C4 to C18 (meth) acrylate monomer, (B) a hydroxyl group-containing copolymerizable monomer as a copolymerizable monomer group, and (F-2) an acryl-containing sulfhydryl group-containing ion The compound is copolymerized to synthesize.

Further, as the copolymer, the other copolymerizable monomer group may include a carboxyl group-containing monomer, a hydroxyl group-free nitrogen-containing vinyl monomer, and a polyalkylene glycol mono(meth)acrylate single. At least one or more of the bodies.

The adhesive composition of the present invention can be obtained by blending (C) a difunctional or higher isocyanate compound, (D) a metal chelate crosslinking catalyst, and (E) a keto-enol tautomer compound in the above copolymer. (F-1) an ionic compound having a melting point of 25 to 50 ° C as an antistatic agent (F), and an appropriate optional additive. Further, if (F-2) an ionic compound containing an acrylonitrile group has been polymerized in the main agent copolymer, the (F-1) melting point of the (F) antistatic agent may be further added to the copolymer. The ionic compound of 25 to 50 ° C may not contain (F-1) an ionic compound having a melting point of 25 to 50 ° C as the (F) antistatic agent.

The copolymer is preferably an acrylic polymer, and preferably contains 50 to 100% by weight of a (meth) acrylate monomer or an acrylic monomer such as (meth)acrylic acid or (meth)acrylamide.

Further, it is preferred that the copolymer has an acid value of 0.01 to 8.0. Thereby, it is possible to improve the staining property and improve the performance of preventing the occurrence of the adhesive residue.

Here, the "acid value" is one of the indexes indicating the acid content, and is expressed by the number of mg of potassium hydroxide required to neutralize 1 g of the carboxyl group-containing polymer.

Preferably, the adhesive layer obtained by crosslinking the above-mentioned adhesive composition has an adhesive force of 0.05 to 0.1 N/25 mm at a low peeling speed of 0.3 m/min, and an adhesive force of 1.0 m at a high peeling speed of 30 m/min. N/25mm or less. Thereby, it is possible to obtain a performance in which the change in the adhesive force with the peeling speed is small, and it is possible to quickly peel off even in the case of high-speed peeling. Further, even if the surface protective film is temporarily peeled off for re-adhesion, it does not require excessive force and is easily peeled off from the adherend.

The surface resistivity of the pressure- ^sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition is preferably 9.0×10 ⁺¹¹ Ω/□ or less, and the peeling static voltage is ±0 to 0.5 kV. Further, in the present invention, the term "±0 to 0.5 kV" means "0 to -0.5 kV" and "0 to +0.5 kV", that is, "-0.5 to +0.5 kV". When the surface resistivity is large, the performance of releasing static electricity due to charging at the time of peeling is inferior. Therefore, by making the surface resistivity sufficiently small, it is possible to reduce the static electricity generated when the adhesive layer is peeled off from the adherend. By peeling off the static voltage, it is possible to suppress the influence on the electric control circuit or the like of the adherend.

The adhesive layer (adhesive after crosslinking) obtained by crosslinking the adhesive composition of the present invention preferably has a gel fraction of 95 to 100%. Since the gel fraction is so high, the adhesion does not become excessive at a low peeling speed, and the phenomenon of eluting unpolymerized monomers or oligomers from the copolymer is lowered, thereby improving reworkability, high temperature/high Durability under wet and inhibit contamination by adherends.

The adhesive film of the present invention is obtained by forming an adhesive layer on one or both sides of a resin film which is obtained by crosslinking the adhesive composition of the present invention. Further, the surface protective film of the present invention is obtained by forming an adhesive layer on one side of a resin film which is obtained by crosslinking the adhesive composition of the present invention. In the adhesive composition of the present invention, since the components (A) to (F) described above are blended with good balance, they have excellent antistatic properties and adhesion at a low peeling speed and a high peeling speed. It is also excellent in balance, durability, and reworkability (the ink is not transferred to the adherend after being drawn on the surface protective film with the pen atom through the adhesive layer). Therefore, a surface protective film as a polarizing plate can be preferably used.

In the adhesive film and the surface protective film of the present invention, a polyester film or the like can be used as the substrate of the resin film or the release film (separator) for protecting the pressure-sensitive adhesive layer.

In addition, the resin film can be formed on the surface of the resin film opposite to the side on which the adhesive layer is formed by a release agent, a coating agent, cerium oxide particles or the like of an anthrone or a fluorine-based release agent. The antifouling treatment can be carried out by an antistatic treatment by application or mixing of an antistatic agent.

In addition, the release film is subjected to a release treatment by a release agent such as an anthrone or a fluorine-based agent on the surface on the side where the adhesive surface of the adhesive layer is bonded.

Example

Hereinafter, the present invention will be specifically described based on examples.

<Manufacture of Acrylic Copolymer>

[Example 1]

Nitrogen gas was introduced into a reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen introduction tube, thereby replacing the air in the reaction device with nitrogen. Then, 100 parts by weight of 2-ethylhexyl acrylate and 3.5 parts by weight of 8-hydroxyoctyl acrylate were added to the reaction apparatus. Then, after 2 hours, 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was added dropwise, and the mixture was reacted at 65 ° C for 6 hours to obtain an acrylic acid for Example 1 having a weight average molecular weight of 500,000. Copolymer solution 1. A part of the acrylic copolymer was taken and used as an acid value measurement sample described later.

[Examples 2 to 6 and Comparative Examples 1 to 3]

The same as the acrylic copolymer solution 1 used in the above Example 1, except that the compositions of the respective monomers were adjusted as shown in (A), (B), (I) and (F-2) in Table 1, respectively. The operation was carried out to obtain the acrylic copolymer solutions used in Examples 2 to 6 and Comparative Examples 1 to 3.

<Manufacture of Adhesive Composition and Surface Protective Film>

[Example 1]

To the acrylic copolymer solution 1 of Example 1 produced as described above, 1.5 parts by weight of 1-octylpyridinium hexafluorophosphate and 4.0 parts by weight of acetamidine acetone were added and stirred, and then 1.5 parts by weight of hexamethylene was added. The isocyanurate of the bis-isocyanate compound (trade name: Coronate HX) and 0.05 parts by weight of tris(2,4-pentanedione)iron (III) were stirred and mixed to obtain the adhesion of Example 1. Composition. The adhesive composition was applied onto a release film composed of a polyethylene terephthalate (PET) film coated with an fluorenone resin, and then dried at 90 ° C to remove the solvent to obtain an adhesive layer. Adhesive sheet with a thickness of 25 μm.

Then, a polyethylene terephthalate (PET) film having an antistatic treatment and an antifouling treatment on one surface is prepared, and the adhesive sheet is transferred to the polyethylene terephthalate (PET) film. On the opposite side to the surface on which the antistatic treatment and the antifouling treatment were carried out, a PET film/adhesive layer/release film (PET film coated with an anthrone resin) having antistatic treatment and antifouling treatment was obtained. The surface protection film of Example 1 which is laminated.

[Examples 2 to 6 and Comparative Examples 1 to 3]

Except that the compositions of the respective additives were adjusted as shown in (C) to (F) and (J) of Table 2, the same operations as in the surface protective film of Example 1 were carried out, and Examples 2 to 6 and The surface protective films of Comparative Examples 1 to 3.

Table 1 and Table 2 are tables in which the entire table showing the mixing ratio of each component is divided into two parts, and the numerical values in the parentheses indicate the weights of the respective components obtained by setting the total amount of the group (A) to 100 parts by weight. Value. In addition, the ratio of (E) / (D) is shown in Table 3. Further, the names of the compounds corresponding to the abbreviations of the respective components used in Tables 1 and 2 are shown in Tables 4 and 5. In addition, Coronate (registered trademark) HX, Coronate HL and Coronate L are trade names of Nippon Polyurethane Industry Co., Ltd., Takenate (registered trademark) D-140N, D- 127N and D-110N are trade names of Mitsui Chemicals Co., Ltd., and Desmodur (registered trademark) N3400 is the trade name of Sumika Bayer Urethane Co., Ltd.

In Table 1, the (F-2) propylene group-containing ionic compound copolymerized in the (F) antistatic agent and the (F) antistatic agent added after polymerization are described in different columns. in.

<Synthesis of difunctional isocyanate compound>

The difunctional isocyanate compounds of Synthesis Examples 1 and 2 were synthesized by the following methods. That is, as shown in Table 6 and Table 7, the diisocyanate and the diol compound were mixed at a molar ratio of NCO/OH = 16, and reacted at 120 ° C for 3 hours, and then removed under reduced pressure by a thin film evaporation apparatus. The unreacted diisocyanate gives the desired difunctional isocyanate compound.

<Test method and evaluation>

After the surface protective films of Examples 1 to 6 and Comparative Examples 1 to 3 were aged for 7 days in an environment of 23 ° C and 50% RH, the release film (PET film coated with an anthrone resin) was peeled off to adhere the film. The agent layer was exposed and used as a sample for measuring the surface resistivity.

Further, the surface protective film exposed to the adhesive layer was bonded to the surface of the polarizing plate adhered to the liquid crystal cell through an adhesive layer, and left for 1 day, and then subjected to autoclave treatment at 50 ° C and 5 atm for 20 minutes. Further, after standing at room temperature for 12 hours, it was used as a sample for measuring adhesion, peeling static voltage, reworkability, and durability.

<adhesion>

Using a tensile tester, the test sample obtained above was peeled off in a 180° direction at a low peeling speed (0.3 m/min) and a high peeling speed (30 m/min) (a 25 mm wide surface protective film was attached) The peeling strength was measured on the sample formed on the surface of the polarizing plate, and the peeling strength was used as the adhesive force.

<surface resistivity>

After aging, before adhering to the polarizing plate, peeling off the peeling film (PET film coated with fluorenone resin) to expose the adhesive layer, using a resistivity meter (Model HirestaUP-HT450 (ハイレスタUP-HT450) Mitsubishi Chemical Analysis Technology Co., Ltd. (manufactured by Mitsubishi Chemical Analytech Co., Ltd.), the surface resistivity of the adhesive layer was measured.

<peeling static voltage>

Using a high-precision electrostatic sensor SK-035, SK-200 (manufactured by Keyence Corporation), it was measured that 180° was taken at a tensile speed of 30 m/min for the above-obtained measurement sample. At the time of peeling, the voltage (static voltage) generated when the polarizing plate is charged is used, and the maximum value of the measured value is taken as the peeling static voltage.

<Reworkability>

After drawing on the surface protective film of the measurement sample obtained above with a ball pen (loading of 500 g, three times back and forth), the surface protective film was peeled off from the polarizing plate, and the surface of the polarizing plate was observed to confirm whether or not the contamination was transferred to the polarizing plate. . Evaluation target criterion: When the contamination is not transferred to the polarizing plate, it is evaluated as "○"; when it is confirmed that the trajectory drawn along the atomic pen is at least partially transferred to the pollution, it is evaluated as "△"; when it is confirmed that the trajectory drawn along the atomic pen is When the contamination was transferred and the adhesion of the adhesive was confirmed from the surface of the adhesive, it was evaluated as "X".

<Storage period>

Immediately after the additives of (C) to (F) and (J) were added, the viscosity η ₀ (initial viscosity) of the adhesive composition was measured, and the adhesive composition was measured after placing the adhesive composition at 23 ° C for 8 hours in a sealed state. The viscosity of the composition was η ₁ (viscosity after 8 hours). As an index of the storage period, the ratio of η ₁ when η ₀ is 1.0, that is, the ratio of η ₁ / η ₀ is obtained. The evaluation target is as follows: when the viscosity after 8 hours is less than 1.25 times the initial viscosity, it is evaluated as "○", and when it is 1.25 times or more and less than 1.50 times, it is evaluated as "△", and it is placed at 1.50 times or more or after 8 hours. When gelation occurred, it was evaluated as "x".

<Durability>

After the measurement sample obtained above was placed in a 60 ° C, 90% RH environment for 250 hours, it was taken out and left at room temperature for further 12 hours, and then the adhesion was measured to confirm whether it was obvious compared with the initial adhesion. Increase. Evaluation target: When the adhesion after the test is 1.5 times or less of the initial adhesion, it is evaluated as "○", and when it is more than 1.5 times, it is evaluated as "X".

The evaluation results are shown in Table 8. Further, the surface resistivity by "mE + n" to represent "m × 10 ^{+ n"} (where, m is an arbitrary real numbers, n-is a positive integer).

For the surface protective films of Examples 1 to 6, the adhesion at a low peeling speed of 0.3 m/min was 0.05 to 0.1 N/25 mm, and the adhesion at a high peeling speed of 30 m/min was 1.0 N/25 mm. Hereinafter, the surface resistivity is 9.0×10 ⁺¹¹ Ω/□ or less, and the peeling static voltage is ±0 to 0.5 kV; and, after being drawn on the surface protective film with the pen holder through the adhesive layer, there is no adhesion to the adherend It is also excellent in the durability after transferring the contamination, having a long storage period and being left in an environment of 60 ° C and 90% RH for 250 hours.

That is, it has excellent antistatic properties, excellent balance of adhesion at low peeling speed and high peeling speed, and long storage period, durability, and reworkability.

Further, in the surface protective films of Examples 1 to 6, since the organic tin compound was not contained in the adhesive composition, the safety was high.

The surface protective film of Comparative Example 1 may have a low peeling speed of 0.3 m/min and a high peeling speed of 30 m/min because it does not contain (C) a difunctional or higher isocyanate compound as a crosslinking agent. The underlying adhesion is too large, the surface resistivity and the peeling static voltage are high, and the reworkability and durability are poor.

The surface protective film of Comparative Example 2 may have a high peeling static voltage because the ratio of the (E) keto-enol tautomer compound to the crosslinking catalyst of the (D) metal chelate compound is small. The storage period is short and the durability is poor.

The surface protective film of Comparative Example 3 may have a storage period of too short due to a small ratio of the (E) keto-enol tautomer compound to the crosslinking catalyst of the (D) metal chelate compound. Since crosslinking has been carried out before coating, coating cannot be performed.

As described above, the surface protective films of Comparative Examples 1 to 3 were not able to satisfy both excellent antistatic properties, excellent balance of adhesion at low peeling speed and high peeling speed, and long shelf life, durability, and durability. All performance requirements such as excellent reworkability.

Claims (12)

An adhesive composition comprising: (A) at least one of (C) a C4 to C18 (meth) acrylate monomer having an alkyl group and (B) a hydroxyl group-containing copolymerizable group as a copolymerizable monomer group 100 parts by weight of the copolymer of the monomer; (C) 0.1 to 10 parts by weight of the difunctional or higher isocyanate compound; (D) 0.001 to 0.5 part by weight of the crosslinking catalyst of the metal chelate; (E) keto-enol mutual mutation 0.1 to 200 parts by weight of the structural compound; and 0.05 to 5 parts by weight of the ionic compound having a melting point of 25 to 50 ° C as the (F) antistatic agent; and a ratio by weight of (E)/(D) of 70 to 700 . The adhesive composition according to claim 1, wherein the (B) hydroxyl group-containing copolymerizable monomer is selected from the group consisting of 8-hydroxyoctyl (meth)acrylate and 6-hydroxyhexyl (meth)acrylate. Ester, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, N-hydroxy(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, and N- At least one or more of the compound groups consisting of hydroxyethyl (meth) acrylamide. The adhesive composition according to claim 1 or 2, wherein, for the (C) difunctional or higher isocyanate compound, the difunctional isocyanate compound is an acyclic aliphatic isocyanate compound and the diisocyanate compound is a compound formed by reacting an alcohol compound; the diisocyanate compound is an aliphatic diisocyanate selected from the group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethyl six One of a group consisting of methylene diisocyanate and a diisocyanate diisocyanate; the diol compound is selected from the group consisting of 2-methyl-1,3-propanediol and 2,2-dimethyl-1 , 3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 3-methyl-1,5-pentanediol, a group of compounds consisting of 2,2-dimethyl-1,3-propanediol monohydroxypivalate, polyethylene glycol, and polypropylene glycol; as a trifunctional isocyanate compound, a hexamethylene diisocyanate compound Different isocyanurate, isophorone diisocyanate compound An addition product of a urate, a hexamethylene diisocyanate compound, an adduct of an isophorone diisocyanate compound, a biuret of a hexamethylene diisocyanate compound, and a condensation of an isophorone diisocyanate compound Isocyanurate of urea, toluene diisocyanate compound, isocyanurate of benzodimethyl diisocyanate compound, isocyanurate of hydrogenated dimethylene diisocyanate compound, adduct of toluene diisocyanate compound An adduct of a benzodimethyl diisocyanate compound and an adduct of a hydrogenated dimethyl diisocyanate compound. The adhesive composition according to claim 1 or 2, wherein the crosslinking catalyst in the adhesive composition is selected from the group consisting of aluminum chelates, titanium chelates, and iron chelates. At least one of the above. The adhesive composition according to claim 1 or 2, wherein the (F) antistatic agent is ionic in an amount of 0.05 to 5.0 parts by weight and a melting point of 25 to 50 ° C with respect to 100 parts by weight of the copolymer. The compound, and/or the amount of copolymerization in the copolymer is 0.1 to 5.0% by weight, and an ionic compound containing an acrylonitrile group. The adhesive composition according to claim 1 or 2, wherein the copolymer as another copolymerizable monomer group includes a carboxyl group-containing monomer, a hydroxyl group-free nitrogen-containing vinyl monomer, and a polyalkylene group At least one or more of the alcohol mono(meth)acrylate monomers, and/or as an additive include a polyether siloxane compound and other general antioxidants. The adhesive composition according to claim 1 or 2, wherein the adhesive layer obtained by crosslinking the adhesive composition has an adhesive force of 0.05 to 0.1 N/25 mm at a low peeling speed of 0.3 m/min. The adhesion at a high peeling speed of 30 m/min was 1.0 N/25 mm or less. The adhesive composition according to claim 1 or 2, wherein the adhesive layer obtained by crosslinking the adhesive composition has a surface resistivity of 9.0 × 10 ^{+ 11} Ω / □ or less, and the peeling static voltage is ± 0 to 0.5 kV. An adhesive film obtained by forming an adhesive layer on one or both sides of a resin film, wherein the adhesive layer is obtained by crosslinking the adhesive composition according to any one of claims 1 to 8. A surface protective film obtained by forming an adhesive layer on one side of a resin film, wherein the adhesive layer is obtained by crosslinking the adhesive composition according to any one of claims 1 to 8, wherein an atom is used. After the pen was drawn on the surface protective film through the adhesive layer, no contamination was transferred to the adherend. The surface protective film according to claim 10, which is used as a surface protective film for a polarizing plate. The surface protective film according to claim 11, wherein an antistatic and antifouling treatment is performed on a surface of the resin film opposite to a side on which the adhesive layer is formed.