TWI582191B - Adhesive composition and surface protection film - Google Patents

Description

Adhesive composition and surface protective film

The present invention relates to an adhesive composition and a surface protective film. More particularly, the present invention relates to providing a surface protection of a polarizing plate which has antistatic properties, excellent balance of adhesion at a low peeling speed and a high peeling speed, and has a long shelf life, excellent durability and reworkability. An adhesive composition for a film and a surface protective film.

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

The various physical properties of the adhesive can be achieved by using an isocyanate crosslinking agent or an epoxy group 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. Crosslinking Reaction to adjust 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, dibutyltin dilaurate, which is an organotin compound, is used as a catalyst for the crosslinking reaction. However, since the dibutyltin compound exhibits harmful toxicity, it is currently avoided.

Therefore, there is a need for a crosslinking catalyst which is an alternative to a dibutyltin compound which can be used in combination with an isocyanate crosslinking agent and which is inexpensive and has a high reaction rate of a crosslinking reaction, but it is difficult to develop and obtain.

In this case in the above process, 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 in the metal chelate compound; and The fluorinated acetonyl) 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 when it is left at a normal temperature. Therefore, in the industrial production of the adhesive, a crosslinking catalyst and a reaction inhibitor are used in order to stop the crosslinking reaction from the time when the raw material of the adhesive composition is blended to the time when the crosslinking reaction is usually started.

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 blend of a catalyst system having a weight ratio of acetone to the aforementioned acetamidine acetone of 2:1 Compound.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1]: JP-A-2011-001440

[Patent Document 2]: JP-A-2008-285681

In the adhesive composition described in Patent Document 1, the addition 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. Amount, but does not describe the amount of crosslinking inhibitor added. 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 use are mentioned. A method of blocking a (block) crosslinking agent such as a blocked isocyanate or the like is carried out, but it 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 has excellent properties even if a metal acetoacetone catalyst such as iron or copper which is highly active at a low temperature is used. Stability and good catalytic activity of metal acetamidine and acetamidine.

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

In order to solve the above problems, the present invention provides an adhesive composition comprising: (A) an alkyl group having a C4 to C18 (meth) acrylate monomer; At least one, and selected from the group consisting of (B) a hydroxyl group-containing copolymerizable monomer, (C) a carboxyl group-containing copolymerizable monomer, (D) a polyalkylene glycol mono (methyl group) as a copolymerizable monomer group Copolymerization of at least one of an acrylate monomer and (E) a hydroxyl group-free nitrogen-containing vinyl monomer or an alkoxy-containing alkyl (meth) acrylate monomer group And an acrylic polymer containing (F) a difunctional or higher isocyanate compound, (G) a metal chelate crosslinking accelerator, (H) a keto-enol tautomer compound, (I) An ionic compound having a melting point of 25 to 50 ° C and/or an ionic compound containing an acrylonitrile group as an antistatic agent, and (J) a polyether modified siloxane compound.

Further, it is preferable that the acrylic polymer contains 50 to 95 parts by weight of the above (A) alkyl group having a carbon number of C4 to C18 based on 100 parts by weight of the total amount of the acrylic polymer of the copolymer. (meth) acrylate monomer, 0.1 to 10 parts by weight of the above (B) hydroxyl group-containing copolymerizable monomer, 0 to 1.0 part by weight of the above (C) carboxyl group-containing copolymerizable monomer, 0 to 50 parts by weight of the above (D) Polyalkylene glycol mono(meth)acrylate single And 0 to 20 parts by weight of the above (E) a hydroxyl group-free nitrogen-containing vinyl monomer or an alkoxy-containing alkyl (meth)acrylate monomer; the above-mentioned adhesive composition contains 0.1 to 10 parts by weight The (F) difunctional or higher isocyanate compound, 0.001 to 0.5 part by weight of the crosslinking promoter of the (G) metal chelate compound, and 0.1 to 200 parts by weight of the above (H) keto-enol tautomer And the antistatic agent contained in the above-mentioned adhesive composition in an amount of 0.05 to 5.0 parts by weight as a total amount of the antistatic agent contained in the above-mentioned (I) antistatic agent, and an antistatic agent copolymerized in the above copolymer, and containing 0.01~ 1.0 part by weight of the above (J) polyether modified siloxane compound.

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 (meth)acrylic acid 4- Hydroxybutyl ester, 2-hydroxyethyl (meth)acrylate, N-hydroxy(meth)acrylamide, N-methylol (meth) acrylamide, N-hydroxyethyl (meth) propylene oxime At least one or more of the compounds consisting of amines.

Further, it is preferred that the (C) carboxyl group-containing copolymerizable monomer is selected from the group consisting of (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, and 2-(methyl). Propylene methoxyethyl hexahydrophthalic acid, 2-(methyl) propylene methoxy hexahydrophthalic acid, 2-(meth) propylene methoxyethyl phthalic acid, 2-(Methyl)acryloxyethyl succinic acid, 2-(methyl) propylene oxiranyl ethyl maleic acid, carboxy polycaprolactone mono(meth) acrylate, 2-(methyl) At least one or more of the compound groups consisting of acryloxyethyltetrahydrophthalic acid.

Further, the (D) polyalkylene glycol mono(meth)acrylate monomer is preferably selected from the group consisting of polyalkylene glycol mono(meth)acrylates and methoxypolyalkylene glycols (A). At least one of acrylate and ethoxypolyalkylene glycol (meth) acrylate.

Further, it is preferable that the acrylic polymer is contained in the (E) hydroxyl group-free nitrogen-containing vinyl monomer or alkoxy-containing (meth)acrylic acid alkyl ester monomer as the copolymerizable monomer group. At least one or more.

In addition, the (F) difunctional or higher isocyanate compound is preferably a compound produced by reacting a diisocyanate compound with a diol compound as an acyclic aliphatic isocyanate compound of a difunctional isocyanate compound. The diisocyanate compound is an aliphatic diisocyanate, preferably selected from the group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, and trimethyl hexamethylene diisocyanate. And consisting of one of the compound groups consisting of amino acid diisocyanate. Further, as the diol compound, it is preferred to be selected from the group consisting of 2-methyl1,3-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 monohydroxyl One of a group of compounds consisting of pivalate, polyethylene glycol, and polypropylene glycol.

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

Further, it is preferable that the (I) antistatic agent is an ionic compound containing 0.1 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, and/or a copolymerization amount in the copolymer An ionic compound containing 0.1 to 5.0% by weight and containing an acrylonitrile group.

Further, it is preferable that the (J) polyether-modified siloxane compound has an HLB value of 7 to 15.

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 a viscosity at a high peeling speed of 30 m/min. The force is 1.0N/25mm or less.

Further, it is preferable that the surface resistivity of the pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition is 9.0 × 10 ^{+ 10} Ω / □ or less, and the peeling static voltage is ± 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, and the pressure-sensitive adhesive layer is formed by crosslinking the pressure-sensitive 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, and the adhesive layer is the above-mentioned adhesive group The product is formed by cross-linking, and the contamination is not transferred to the adherend after the surface of the surface protective film is drawn by the pen holder through the adhesive layer.

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

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

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 by the prior art without using the organotin compound, and it is possible to obtain excellent antistatic properties and prevent sticking. The occurrence of pesticide residue. 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 an ideal embodiment.

The adhesive composition of the present invention is characterized in that the main component is at least one selected from the group consisting of (A) alkyl groups having a C4 to C18 (meth) acrylate monomer, and is selected from the group consisting of The (B) hydroxyl group-containing copolymerizable monomer, (C) carboxyl group-containing copolymerizable monomer, (D) polyalkylene glycol mono(meth)acrylate monomer, and (E) of the copolymerizable monomer group At least one of a group of copolymerizable monomers consisting of a hydroxyl group-free nitrogen-containing vinyl monomer or an alkoxy-containing alkyl (meth)acrylate monomer The copolymer is composed of an acrylic polymer, and further contains (F) a difunctional or higher isocyanate compound, (G) a metal chelate crosslinking accelerator, and (H) a keto-enol tautomer compound, (I) an ionic compound having a melting point of 25 to 50 ° C and/or an ionic compound containing an acrylonitrile group as an antistatic agent, and (J) a polyether modified siloxane compound.

Further, the acrylic polymer having a total amount of 100 parts by weight of the copolymer is preferably an acrylic polymer containing 50 to 95 parts by weight of (A) an alkyl group having a carbon number of C4 to C18 (methyl). Acrylate monomer, 0.1 to 10 parts by weight of (B) hydroxyl group-containing copolymerizable monomer, 0 to 1.0 part by weight of (C) carboxyl group-containing copolymerizable monomer, 0 to 50 parts by weight of (D) polyalkylene group II An alcohol mono(meth)acrylate monomer, and 0 to 20 parts by weight of (E) a hydroxyl group-free nitrogen-containing vinyl monomer or an alkoxy-containing alkyl (meth)acrylate monomer.

Further, the acrylic polymer having a total amount of the copolymer of 100 parts by weight is preferably 0.1 to 10 parts by weight of the (F) difunctional or higher isocyanate compound, and 0.001 to 0.5 part by weight (G). a crosslinking accelerator of a metal chelate compound and 0.1 to 200 parts by weight of a (H) keto-enol tautomer compound, and a total amount of 0.05 to 5.0 parts by weight as the (I) antistatic agent The antistatic agent contained in the composition and the antistatic agent copolymerized in the copolymer are 0.01 to 1.0 part by weight of (J) a polyether modified siloxane compound.

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, (meth) propylene Acid oxime ester, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, (methyl) Tetradecyl acrylate, pentadecyl (meth) acrylate, cetyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate , (myristyl) (meth) acrylate, isotetradecyl (meth) acrylate, cetyl (meth) acrylate, isohexadecyl (meth) acrylate, stearic acid (meth) acrylate An oxime ester, an isostearyl (meth) acrylate or the like.

When the total amount of the acrylic polymer of the copolymer is 100 parts by weight, the content of the (meth) acrylate monomer having a CA to C18 carbon number of the (A) alkyl group is preferably 50 to 95 parts by weight. .

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

It is preferred that the above hydroxyl group-containing copolymerizable monomer is selected from the group consisting of 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, a compound consisting of 2-hydroxyethyl methacrylate, N-hydroxy(meth) acrylamide, N-methylol (meth) acrylamide, and N-hydroxyethyl (meth) acrylamide At least one or more of the groups.

When the total amount of the acrylic polymer of the copolymer is 100 parts by weight, the content of the (B) hydroxyl group-containing copolymerizable monomer is preferably 0.1 to 10 parts by weight.

The (C) carboxyl group-containing copolymerizable monomer is preferably selected from (Meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, 2-(meth)acryloxyethylhexahydrophthalic acid, 2-(methyl)propylene醯oxypropyl hexahydrophthalic acid, 2-(meth) propylene methoxyethyl phthalate, 2-(methyl) propylene methoxyethyl succinic acid, 2-(methyl) At least one of a group consisting of acryloxyethyl maleic acid, carboxypolycaprolactone mono(meth)acrylate, and 2-(meth)acryloxyethyltetrahydrophthalic acid the above.

When the total amount of the acrylic polymer of the copolymer is 100 parts by weight, the content of the (C) carboxyl group-containing copolymerizable monomer is preferably 0 to 1.0 part by weight. The adhesive composition in the adhesive layer of the present invention may not contain (C) a carboxyl group-containing copolymerizable monomer.

The (D) polyalkylene glycol mono(meth)acrylate monomer is a compound in which one of a plurality of hydroxyl groups of the polyalkylene glycol is esterified to a (meth)acrylate. Just fine. Since the (meth) acrylate group is a polymerizable group, it can be copolymerized with the main agent polymer. The other hydroxyl group may be in an OH state, 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.

Ideally composed of (D) polyalkylene glycol mono(meth)acrylate monomers The average number of repeats of the alkylene oxide chain alkylene oxide is from 3 to 14. The term "average repeat number of alkylene oxide" means the olefin in the "polyalkylene glycol chain" portion contained in the molecular structure of the (D) polyalkylene glycol mono(meth)acrylate monomer. The average number of oxygenation unit repeats.

As the (D) polyalkylene glycol mono(meth)acrylate monomer, it is preferably selected from polyalkylene glycol mono(meth)acrylates, methoxypolyalkylene glycols (methyl groups). At least one of an acrylate 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) propylene Esters, ethoxylated - polyethylene glycol - polypropylene glycol - (meth) acrylate, ethoxy - polyethylene glycol - polypropylene glycol - polyethylene glycol - (meth) acrylate.

When the total amount of the acrylic polymer of the copolymer is set to 100 parts by weight The content of the (D) polyalkylene glycol mono(meth)acrylate monomer is preferably from 0 to 50 parts by weight. The adhesive composition in the adhesive layer of the present invention may not contain (D) a polyalkylene glycol mono(meth)acrylate monomer.

In (E), examples of the (E-1) nitrogen-containing vinyl monomer include a vinyl monomer containing a guanamine bond, a vinyl monomer containing an amine group, and a heterocyclic ring structure having a nitrogen-containing structure. Vinyl monomer and the like. More specifically, N-vinyl-2-pyrrolidone, N-vinylpyrrolidone, methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinyl piperazine N-vinylpyrene , N-vinylpyrrole, N-vinylimidazole, N-vinyl Oxazole, N-vinyl Cyclic nitrogen vinyl compound having an N-vinyl substituted heterocyclic structure such as porphyrin, N-vinyl caprolactam, N-vinyl dodecylamine or the like; N-(meth) acrylonitrile group Porphyrin, N-(methyl)propenyl sulfhydryl , N-(methyl) acrylonitrile aziridine, N-(methyl) propylene decylpyridinium, N-(methyl) propylene decyl pyrrolidine, N-(methyl) propylene sulfhydryl Ring having a N-(meth)acrylinyl group-substituted heterocyclic ring structure such as pyridine, N-(methyl)propenylfluorenyl azepine or N-(methyl)propenyl azepine Nitro-vinyl compound; N-cyclohexylmaleimide, N-phenylmaleimide, etc. cyclic nitrogen-vinyl group having a heterocyclic structure containing a nitrogen atom and a vinyl-based unsaturated bond in the ring a compound; (meth) acrylamide, N-methyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-tert-butyl (meth) acrylamide, etc., unsubstituted Or monoalkyl-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)propene a dialkyl-substituted (meth) acrylamide such as guanamine, N-methyl-N-propyl (meth) acrylamide or N-methyl-N-isopropyl (meth) acrylamide; N,N-dimethylaminomethyl (Meth) acrylate, N,N-dimethylaminoethyl (meth) acrylate, N,N-dimethylaminopropyl (meth) acrylate, N,N-dimethyl Aminoisopropyl (meth) acrylate, N,N-dimethylaminobutyl (meth) acrylate, N,N-diethylaminomethyl (meth) acrylate, N, N-Diethylaminoethyl (meth) acrylate, N-ethyl-N-methylaminoethyl (meth) acrylate, N-methyl-N-propylaminoethyl ( Methyl) acrylate, N-methyl-N-isopropylaminoethyl (meth) acrylate, N,N-dibutylaminoethyl (meth) acrylate, tert-butylamino group Dialkylamino (meth) acrylate such as ethyl (meth) acrylate; N,N-dimethylaminopropyl (meth) acrylamide, N,N-diethylaminopropyl (meth)acrylamide, N,N-dipropylaminopropyl (meth) acrylamide, N,N-diisopropylaminopropyl (meth) acrylamide, N- Ethyl-N-methylaminopropyl (meth) acrylamide, N-methyl-N-propylaminopropyl (meth) acrylamide, N-methyl-N-isopropyl N,N-dialkyl substituted aminopropyl (methyl) such as aminopropyl (meth) acrylamide N-vinylcarbamide, N-vinylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide, N-vinylcarboxylic acid amides; N-methoxymethyl (Meth) acrylamide, N-ethoxyethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, diacetone acrylamide, N, N-methylene (meth) acrylamide such as bis(methyl) acrylamide; unsaturated carboxylic acid nitriles such as (meth)acrylonitrile;

The (E-1) nitrogen-containing vinyl monomer preferably does not contain a hydroxyl group, and more preferably contains no hydroxyl group or carboxyl group. As such a monomer, preferred are the monomers exemplified above, for example, an acrylic monomer containing an N,N-dialkyl substituted amine group, an N,N-dialkyl substituted decylamino group; N-vinyl- N-vinyl substituted indoleamines such as 2-pyrrolidone, N-vinyl caprolactam, N-vinyl-2-piperidone, etc.; N-(methyl) propylene fluorenyl An N-(methyl) acrylonitrile-substituted cyclic amine such as a porphyrin or N-(methyl)propenylpyrrolidine.

In (E), as the (E-2) alkoxy group-containing (meth)acrylic acid alkyl ester monomer, 2-methoxyethyl (meth)acrylate or (meth)acrylic acid may be mentioned. 2-ethoxyethyl ester, 2-propoxyethyl (meth)acrylate, 2-isopropoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, (A) 2-Methoxypropyl acrylate, 2-ethoxypropyl (meth)acrylate, 2-propoxypropyl (meth)acrylate, 2-isopropoxypropyl (meth)acrylate , 2-butoxypropyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 3-propoxy (meth)acrylate Propyl ester, 3-isopropoxypropyl (meth)acrylate, 3-butoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, 4-(meth)acrylate Ethoxybutyl ester, 4-propoxybutyl (meth)acrylate, 4-isopropoxybutyl (meth)acrylate, 4-butoxybutyl (meth)acrylate, and the like.

These alkoxy-containing alkyl (meth) acrylate monomers have a structure in which an atom of an alkyl group in an alkyl (meth) acrylate is substituted with an alkoxy group.

When the total amount of the acrylic polymer of the copolymer is set to 100 parts by weight, it is preferably (E-1) a hydroxyl group-free vinyl monomer or (E-2) alkoxy group-containing (methyl group) The content of the alkyl acrylate monomer is 0 to 20 parts by weight. For (E-1) a hydroxyl group-free vinyl monomer and (E-2) an alkoxy group-containing (meth)acrylic acid alkyl ester monomer, one type may be used alone or two types may be used together. More than one species. The adhesive composition of the pressure-sensitive adhesive layer of the present invention may not contain (E) a nitrogen-containing vinyl monomer or alkoxy-containing (meth)acrylic acid alkyl ester monomer.

The (F) 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 a classification of an aliphatic isocyanate, an aromatic isocyanate, an acyclic isocyanate, an alicyclic isocyanate, and the like, 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 (TOID), 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 (F) difunctional or higher isocyanate compound, only the (F-1) trifunctional isocyanate compound or the (F-2) difunctional isocyanate compound can be used. Further, a (F-1) trifunctional isocyanate compound and a (F-2) difunctional isocyanate compound may be used in combination.

Further, the (F-1) trifunctional isocyanate compound used in the present invention preferably contains at least one selected from the group consisting of (F-1-1) a first aliphatic isocyanate compound and is selected from (F-1). -2) at least one or more of the second aromatic isocyanate compound group, wherein the aforementioned (F-1-1) first aliphatic type is different The cyanate compound group is an isocyanurate of a hexamethylene diisocyanate compound, an isocyanurate of an isophorone diisocyanate compound, an adduct of a hexamethylene diisocyanate compound, and an isophor. An adduct of a keto diisocyanate compound, a biuret of a hexamethylene diisocyanate compound, and a biuret of an isophorone diisocyanate compound; the aforementioned (F-1-2) second aromatic isocyanate compound The group is an isocyanurate of a toluene diisocyanate compound, an isocyanurate of a benzene dimethyl diisocyanate compound, an isocyanurate of a hydrogenated dimethyl dimethyl diisocyanate compound, and an addition of a toluene diisocyanate compound. And an adduct of an benzodimethyl diisocyanate compound and an adduct of a hydrogenated dimethyl diisocyanate compound. It is desirable to use (F-1-1) a first aliphatic isocyanate compound group and (F-1-2) a second aromatic isocyanate compound group in combination. In the present invention, as the (F-1) trifunctional isocyanate compound, at least one selected from the group consisting of (F-1-1) first aliphatic isocyanate compounds and selected from (F-1- 2) At least one or more of the second aromatic isocyanate compound group can further improve the balance of the adhesion force in the low-speed peeling region and the high-speed peeling region.

Further, the (F-1) trifunctional isocyanate compound preferably includes at least one selected from the group consisting of the above (F-1-1) first aliphatic isocyanate compound and selected from the above (F-1-2) At least one or more of the diaromatic isocyanate compound groups, and the total content of the (F) trifunctional or higher isocyanate compound is 0.5 to 5.0 parts by weight based on 100 parts by weight of the copolymer. Further, at least one or more selected from the group consisting of (F-1-1) a first aliphatic isocyanate compound group and at least one selected from the group consisting of (F-1-2) a second aromatic isocyanate compound group The ratio, calculated by weight ratio, is ideally (F-1-1): (F-1-2) In the range of 10%: 90%~90%: 10%.

Further, the (F-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 by the formula "HO-Y-OH" (wherein Y is a divalent group) 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=N-X-(NH-CO-O-Y-O-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 (diisocyanate compound which is not reacted with respect to the diol compound), and is preferably a compound containing n as an essential component as an essential component. . The difunctional acyclic aliphatic isocyanate compound may also be a mixture of a plurality of compounds different from n in the general formula Z.

The diisocyanate compound represented by the formula "O=C=N-X-N=C=O" is an aliphatic diisocyanate. It is desirable that X is an acyclic aliphatic divalent group. The aliphatic diisocyanate is preferably selected from the group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethyl hexamethylene diisocyanate, and lysine di One or two or more of the compound groups consisting of isocyanates are used.

The diol compound represented by the formula "HO-Y-OH" is an aliphatic diol. It is desirable that Y is a non-cyclic aliphatic divalent group. The diol compound is preferably selected from the group consisting of 2-methyl1,3-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 two or more of the compound groups consisting of an acid ester, polyethylene glycol, and polypropylene glycol.

It is preferable that the weight ratio (F-1/F-2) of the (F-1) trifunctional isocyanate compound to the (F-2) difunctional isocyanate compound is from 1 to 90. The amount of the above-mentioned (F) difunctional or higher isocyanate compound is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the acrylic polymer.

When the polyisocyanate compound is used as the crosslinking agent, the crosslinking accelerator of the (G) metal chelate compound is a substance that functions as a catalyst to react with the copolymer and the crosslinking agent (crosslinking reaction). 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 used as a crosslinking accelerator in the present invention.

The metal chelate compound is a compound in which one or more multidentate ligands L are bonded to the central metal atom M. The metal chelate compound may or may not have one or more monodentate ligands X bonded to the metal atom M. For example, when the general formula of a metal chelate compound having a metal atom M of one 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 Fe, Ni, Mn, Cr, V, Ti, Ru, Zn, Al, Zr, and Sn.

Examples of the polydentate ligand L include methyl ethyl acetate, ethyl acetate, octyl acetate, ethyl acetoacetate, lauryl acetate, and stearyl acetate. beta] - keto ester; Acetylacetonates: β (alias 2,4-pentanedione), 2,4-hexanedione, benzoyl acetone, etc. - dione. These 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 or a bromine atom, a pentamidine group, a hexyl group, a 2-ethylhexyl group, a octyl group, an anthracenyl group, a fluorenyl group, and a fluorenyl group. An alkoxy group such as a stearyl group or an alkoxy group such as a methoxy group, an ethoxy group, a n-propoxy group, an isopropoxy group or a butoxy group.

Specific examples of the metal chelate compound include tris(2,4-pentanedione)iron (III), triethylsulfonium acetonide, titanium triacetate, triethyl acetonide oxime, and diethyl acetonide. Zinc, aluminum triacetate, aluminum tetraacetate, zirconium, tris(2,4-hexanedione) iron (III), bis(2,4-hexanedione) zinc, tris(2,4-hexanedione) Titanium, tris(2,4-hexanedione)aluminum, 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, a fatty acid salt of stannous, and the like. 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 an endocrine disrupting substance. From the viewpoint of safety, a long-chain alkyl tin compound such as a dioctyltin compound is preferable. Specific examples of the organotin compound include dioctyltin oxide, dioctyltin dilaurate, and the like. although It is also possible to use the Sn compound temporarily, but in view of the tendency to use a more safe substance in the future, it is desirable 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 a compound selected from the group consisting of an aluminum chelate compound, a titanium chelate compound, an iron chelate compound, and a tin chelate compound (which does not contain TBT). At least one of the groups.

The content of the crosslinking accelerator of the (G) 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 (H) 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 having a polyisocyanate compound as a crosslinking agent, by blocking the isocyanate group of the crosslinking agent, it is possible to suppress excessive increase in viscosity or coagulation of the viscosity of the adhesive composition after the crosslinking agent is blended. The phenomenon of gelation can prolong the shelf life of the adhesive composition.

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

The (H) keto-enol tautomer compound has an effect of inhibiting crosslinking as opposed to the crosslinking accelerator of the (G) metal chelate compound, and therefore, it is desirable to appropriately set (H) keto-enol tautomerization. The ratio of the bulk compound to the crosslinking accelerator of the (G) metal chelate. In order to prolong the storage period of the adhesive composition and improve storage stability, the weight ratio of (G):(H) is preferably in the range of 1:1 to 1:300, more preferably 1:30 to 1:300. The ideal is 1:80~1:300.

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

The (I) antistatic agent is preferably (I-1) an ionic compound having a melting point of 25 to 50 ° C and/or (I-2) an ionic compound containing an acryl fluorenyl group.

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

The (I-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 nitrogen-containing phosphonium cation such as a pyrrolidine cation or an ammonium cation, or a phosphonium cation or a phosphonium cation, and the anion is hexafluorophosphate (PF ₆ ^- ), thiocyanate (SCN ^- ), alkylbenzenesulfonate (RC ₆ H A compound of an inorganic or organic anion such as ₄ SO ₃ ^- ), perchlorate (ClO ₄ ^- ) or tetrafluoroborate (BF ₄ ^- ). It is preferred to be 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, the position and number of the substituents, and the like. The cation is preferably a 4-stage ruthenium cation, and a 4-stage pyridinium cation such as 1-alkylpyridinium (having a substituent or a substituent at the carbon atom of 2 to 6) may be mentioned. A 4-stage imidazolium cation such as a 3-dialkylimidazolium (a carbon atom at the 2, 4, or 5 position may have a substituent or a substituent), or a 4- to ammonium cation such as a tetraalkylammonium.

It is desirable that the (I-1) melting point is 25 to 50 with respect to 100 parts by weight of the copolymer. The content of the ionic compound at °C is 0.1 to 5.0 parts by weight.

The ionic compound containing an acryl fluorenyl group (I-2) is an ionic compound having a cation and an anion, and examples thereof include a (meth) propylene decyloxyalkyltrialkylammonium (R ₃ N ^{+ ).} -C _n H _2n -OCOCQ=CH ₂ , wherein (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 ( ^{F F} ₂ N ^- ) containing F 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) quinone imide [(FSO ₂ ) ₂ N ^- ], bis(trifluoromethanesulfonyl) fluorenylene [[CF _3] SO ₂ ) ₂ N ^- ], bis(sulfonyl sulfonyl) ruthenium [(C ₂ F ₅ SO ₂ ) ₂ N ^- ] and the like.

The amount of the ionic compound containing the propylene fluorenyl group (I-2) is preferably 0.1 to 5.0% by weight in the copolymer.

Specific examples of the (I) antistatic agent are not particularly limited, and specific examples of the (I-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, and the like. Further, specific examples of the (I-2) ionic compound containing an acryl fluorenyl 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) quinone 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 may optionally contain (J) a polyether modified siloxane compound. (J) The polyether-modified siloxane compound is a siloxane compound having a polyether group, and has a fluorene containing a polyether group in addition to a usual siloxane unit (-SiR ¹ ₂ -O-) Oxysilane unit (-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 ).

The (J) polyether modified siloxane compound is preferably a polyether modified siloxane compound having an HLB value of 7 to 15. Further, the content of the (J) 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).

(J) A polyether-modified oxoxane compound can be obtained, for example, by grafting an organic compound having an unsaturated bond and a polyoxyalkylene group to a poly(alkylene group)-polymerized by a hydrogenation sulfonation reaction. Obtained from the main chain of organic decane. Specifically, a dimethyl methoxy oxane-methyl (polyoxyethylene) decane copolymer, dimethyl methoxy oxane-methyl (polyoxyethylene) decane-methyl (poly) Propylene oxide) decane copolymer, dimethyl methoxy alkane-methyl (polyoxypropylene) siloxane copolymer Wait.

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

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 accelerator, 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 as the adhesive composition of the present invention can be selected from at least one of (C) a C-C18-C18 (meth) acrylate monomer having an alkyl group (B) a hydroxyl group-containing copolymerizable monomer, (C) a carboxyl group-containing copolymerizable monomer, (D) a polyalkylene glycol mono(meth)acrylate monomer, and a copolymerizable monomer group (E) at least one of a group of copolymerizable monomers composed of a hydroxyl group-free vinyl monomer or an alkoxy group-containing (meth)acrylic acid alkyl ester monomer is copolymerized and 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 (I-2) an ionic compound containing an acrylonitrile group is used as the (I) antistatic agent, the copolymer of the main agent used in the adhesive composition of the present invention can be obtained by carbon of (A) alkyl group At least one of a (meth) acrylate monomer having an atomic number of C4 to C18, and (B) a hydroxyl group-containing copolymerizable monomer selected from the group of copolymerizable monomers, and (C) a carboxyl group-containing one Comonomer, (D) polyalkylene glycol mono(meth)acrylate monomer, and (E) hydroxyl-free, nitrogen-containing vinyl monomer or alkoxy-containing At least one of the copolymerizable monomer groups composed of the alkyl (meth)acrylate monomer and the (I-2) acryl-containing ionic group-containing ionic compound are copolymerized and synthesized.

The adhesive composition of the present invention may be obtained by blending (F) a difunctional or higher isocyanate compound, (G) a metal chelate crosslinking accelerator, and (H) a keto-enol mutual mutation in the copolymer. The composition compound, (I) an antistatic agent, (J) a polyether modified siloxane compound, and any suitable additives are used for formulation. Further, when (I-2) an ionic compound containing an acrylonitrile group has been polymerized in the main agent copolymer, the (I) antistatic agent may be further added to the copolymer, or (I) may not be added. 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 acrylic polymer 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.

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. 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-sticking, it does not require excessive force and is easily peeled off from the adherend.

It is preferable that the surface resistivity of the pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition is 9.0 × 10 ^{+ 10} 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 poor. Therefore, by making the surface resistivity sufficiently small, it is possible to reduce static electricity generated when the adhesive layer is peeled off from the adherend. The generated peeling static voltage can suppress the influence on the electric control circuit or the like of the adherend.

It is preferable that the adhesive layer (adhesive after crosslinking) obtained by crosslinking the adhesive composition of the present invention 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, so that reworkability, high temperature/high can be improved. Durability under wet and inhibit contamination of the adherend.

The adhesive film of the present invention is obtained by forming an adhesive layer on one surface or both surfaces of a resin film, and the pressure-sensitive adhesive layer 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 surface of a resin film, and the pressure-sensitive adhesive layer is formed by crosslinking the adhesive composition of the present invention. In the adhesive composition of the present invention, since the components (A) to (J) described above are blended with good balance, they have excellent antistatic properties and are sticky at low peeling speed and high peeling speed. The balance of the force is excellent, and the durability and the reworkability (the ink is not transferred to the adherend after being drawn on the surface protective film with the pen holder through the adhesive layer) is also excellent. Therefore, it can be suitably used as a surface protective film for a polarizing plate.

As the base film of the pressure-sensitive adhesive layer and the release film (separator) for protecting the adhesive surface, a resin film such as a polyester film or the like can be used.

For the substrate film, it may be opposite to the side of the resin film on which the adhesive layer is formed. The anti-fouling treatment by an antimony ketone, a fluorine-based release agent, a coating agent, or cerium oxide fine particles can be carried out on the surface to carry out antistatic treatment by application or mixing of an antistatic agent. .

In the release film, a release treatment by an anthrone or a fluorine release agent is performed on the surface on the side where the adhesive surface of the pressure-sensitive adhesive layer is bonded.

[Examples]

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 apparatus with nitrogen. Then, 100 parts by weight of 2-ethylhexyl acrylate, 3.0 parts by weight of 8-hydroxyoctyl acrylate, and 10 parts by weight of polypropylene glycol monoacrylate (constituting a polyalkylene glycol chain) were added to the reaction apparatus. The average number of repetitions of the alkylene oxide was n = 12), and 60 parts by weight of a solvent (ethyl acetate) was simultaneously added. Then, 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was added dropwise thereto over 2 hours, and the mixture was reacted at 65 ° C for 6 hours to obtain a copolymer of acrylic acid used in Example 1 having a weight average molecular weight of 500,000. Solution 1. A part of the acrylic copolymer was taken and used as an acid value measurement sample described later.

[Examples 2 to 6, Reference Examples 1 to 3, and Comparative Examples 1 to 4]

The operation was carried out in the same manner as in the above-described acrylic copolymer solution 1 of Example 1 except that the compositions of the respective monomers were adjusted as described above in (A) to (E) and (I-2) in Table 1. The acrylic copolymer solutions used in Examples 2 to 6, Reference Examples 1 to 3, and Comparative Examples 1 to 4 were used.

<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, 0.05 parts by weight of a polyether modified siloxane compound (HLB=7), and 8.5 weight were added. After stirring and stirring acetonitrile, 2.0 parts by weight of Coronate HX (isocyanurate of hexamethylene diisocyanate compound) and 0.1 part by weight of titanium triacetate were added and stirred to obtain the viscosity of Example 1. The composition of the agent. 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 adhesion. The adhesive layer had 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). On the opposite side of the film to the surface on which the antistatic treatment and the antifouling treatment were carried out, a PET film/adhesive layer/release film (coated with an anthrone resin) having antistatic treatment and antifouling treatment was obtained. The surface protective film of Example 1 in which the PET film was laminated.

[Examples 2 to 6, Reference Examples 1 to 3, and Comparative Examples 1 to 4]

Except that the composition of each additive was adjusted as described above in (F) to (J) of Table 2, the same operation as the surface protective film of Example 1 was carried out, and Examples 2 to 6 and Reference Examples 1 to 3 were obtained. And compare the surface protection film of 1~4.

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. Further, the names of the compounds corresponding to the abbreviations of the respective components used in Tables 1 and 2 are shown in Tables 3 and 4. Further, 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, D -110N, D-120N is the trade name of Mitsui Chemicals Co., Ltd., and Desmodur (registered trademark) N3400 is the trade name of Sumika Bayer Urethane Co., Ltd.

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

<Synthesis of difunctional isocyanate compound>

The difunctional isocyanate compounds of Synthesis Examples 1 to 3 were synthesized by the following methods. That is, as shown in Table 5 and Table 6, 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. Reaction of diisocyanate, obtained The desired difunctional isocyanate compound.

<Test method and evaluation>

After the surface protective films of Examples 1 to 6, Reference Examples 1 to 3, and Comparative Examples 1 to 4 were aged for 7 days in an environment of 23 ° C and 50% RH, the release film (PET coated with an anthrone resin) was peeled off. The film) was exposed to the adhesive layer and used as a sample for measuring the surface resistivity.

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

<adhesion>

Using a tensile tester, the above-obtained measurement sample was peeled off at a low peeling speed (0.3 m/min) and a high peeling speed (30 m/min) in a 180° direction (a 25 mm wide surface protective film was attached to the polarized light). The peeling strength was measured on the surface of the board), and this peeling strength was made into the adhesive force.

<surface resistivity>

After aging, before peeling off the polarizing plate, peel off the release film (coated with fluorenone resin) The PET film was exposed to the adhesive layer, and the surface resistance of the adhesive layer was measured using a resistivity meter HirestaUP-HT450 (manufactured by Mitsubishi Chemical Analytech Co., Ltd.). rate.

<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>

The surface protective film of the measurement sample obtained above was drawn with a ball pen (loading was 500 g, three times back and forth), and 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 has The contamination was transferred and evaluated as "X" when the adhesion of the adhesive was also confirmed from the surface of the adhesive.

<Storage period>

Immediately after the addition of the additives of (F) to (J), the viscosity η ₀ (initial viscosity) of the adhesive composition was measured, and the adhesive composition was measured after the adhesive composition was placed at 23 ° C for 8 hours in a sealed state. The viscosity of the material 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 was as follows: when the viscosity after 8 hours was less than 1.25 times the initial viscosity, it was evaluated as "○", and when it was 1.25 times or more and less than 1.50 times, it was evaluated as "△", and it was 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 an environment of 60 ° C and 90% RH 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 criterion: When the adhesion after the test was 1.5 times or less of the initial adhesive force, it was evaluated as "○", and when it was more than 1.5 times, it was evaluated as "X".

The evaluation results are shown in Table 7. Further, in 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 and Reference Examples 1 to 3, 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. It is 1.0 N/25 mm or less; the surface resistivity is 9.0×10 ⁺¹⁰ Ω/□ or less, and the peeling static voltage is ±0 to 0.5 kV; and after the surface protective film is drawn through the adhesive layer with a ball pen The durability was not transferred to the adherend, and the durability was long after the storage period was long and was allowed to stand in an environment of 60 ° C and 90% RH for 250 hours.

That is, it has excellent antistatic performance, is excellent in balance of adhesive force at a low peeling speed and a high peeling speed, and is excellent in a long storage period, durability, and reworkability.

Further, in the surface protective films of Examples 1 to 6, since the adhesive composition does not contain an organotin compound, it is highly safe.

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 (F) a difunctional or higher isocyanate compound as a crosslinking agent. Excessive adhesion, high surface resistivity and peeling static voltage, poor reworkability and durability.

For the surface protective film of Comparative Example 2, it may be because the ratio of the (H) keto-enol tautomer compound to the crosslinking accelerator of the (G) metal chelate is small, and (J) polyether The HLB value of the modified siloxane compound is too large, and the peeling static voltage is high, the storage period is short, and the durability is poor.

The surface protective film of Comparative Example 3 may be due to the use of a crosslinking accelerator of an organotin compound instead of the crosslinking accelerator of the (G) metal chelate compound, and the (H) keto-enol tautomer compound relative to When the ratio of the crosslinking accelerator is small, the storage period is too short, and crosslinking has been carried out before coating, so that coating cannot be performed.

For the surface protective film of Comparative Example 4, it may be due to the absence of (G) metal a chelate crosslinking accelerator and (H) keto-enol tautomer compound, and without (J) polyether modified siloxane compound, its viscosity at a high peeling speed of 30 m/min Excessive force, short storage period and poor durability.

As described above, the surface protective films of Comparative Examples 1 to 4 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 (4)

A surface protective film formed by forming an adhesive layer on one side of a resin film, the adhesive layer being an adhesive containing an acrylic polymer, (I) an antistatic agent, and (F) a crosslinking agent. The acrylic polymer is obtained by crosslinking at least one of (C) a C-C18-containing (meth) acrylate monomer having a (A) alkyl group and (B) a hydroxyl group. At least one of copolymerizable monomers, and (C) carboxyl group-containing copolymerizable monomer, (D) polyalkylene glycol mono(meth)acrylate single selected from the group of copolymerizable monomers And (E) at least one copolymerizable monomer group consisting of a hydroxyl group-free vinyl monomer or a hydroxyl group-free alkoxy group-containing (meth)acrylic acid alkyl ester monomer The (B) hydroxyl group-containing copolymerizable monomer formed from the acrylic polymer of the copolymer is selected from the group consisting of 8-hydroxyoctyl (meth)acrylate and 6-hydroxyhexyl (meth)acrylate. , 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, N-hydroxy(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-hydroxyl Ethyl (meth) propylene oxime At least one or more of the compound group composed of an amine, the adhesive composition further contains (G) a metal chelate crosslinking accelerator, (H) a keto-enol tautomer compound, and (J) a polyether modified siloxane compound having an HLB value of 7 to 15 and containing 0.001 to 0.5 part by weight of a crosslinking accelerator of the (G) metal chelate with respect to 100 parts by weight of the total amount of the acrylic polymer And 0.1 to 200 parts by weight of the (H) keto-enol tautomer compound, the weight ratio of (G):(H) being 1:80 to 1:300, The (G) metal chelate compound is a titanium chelate compound or an iron chelate compound. The surface protective film of claim 1, wherein the acrylic polymer contains: 50 to 95 parts by weight of the carbon atom of the (A) alkyl group based on 100 parts by weight of the total amount of the acrylic polymer. The number is C4 to C18 (meth) acrylate monomer, 0.1 to 10 parts by weight of the (B) hydroxyl group-containing copolymerizable monomer, and 0 to 1.0 part by weight of the (C) carboxyl group-containing copolymerizable monomer , 0 to 50 parts by weight of the (D) polyalkylene glycol mono(meth)acrylate monomer, and 0 to 20 parts by weight of the (E) hydroxyl group-free nitrogen-containing vinyl monomer or An alkoxy group-containing alkyl (meth)acrylate monomer which does not contain a hydroxyl group; the adhesive composition contains 0.1 to 10 parts by weight of a difunctional or higher isocyanate compound as the (F) crosslinking agent, As the (I) antistatic agent, the adhesive composition contains 0.1 to 5.0 parts by weight of an ionic compound having a melting point of 25 to 50 ° C and/or 0.1 to 5.0 parts by weight of the propylene-containing group in the copolymer. The total amount of the ionic compound is 0.1 to 5.0 parts by weight, and 0.01 to 1.0 part by weight of the (J) polyether modified siloxane compound having an HLB value of 7 to 15. The surface protective film according to claim 1 or 2, wherein the (C) carboxyl group-containing copolymerizable monomer is selected from (meth)acrylic acid, carboxyethyl (meth)acrylate, (methyl) ) carboxypentyl acrylate, 2-(methyl) propylene decyloxy Ethyl hexahydrophthalic acid, 2-(methyl)propenyloxypropyl hexahydrophthalic acid, 2-(meth) propylene methoxyethyl phthalate, 2-(methyl ) acryloxyethyl succinic acid, 2-(methyl) propylene oxiranyl ethyl maleic acid, carboxy polycaprolactone mono (meth) acrylate, 2-(methyl) propylene methoxy ethoxylate At least one or more of the group consisting of tetrahydrophthalic acid, the (D) polyalkylene glycol mono(meth)acrylate monomer is selected from polyalkylene glycol mono (methyl) At least one of acrylate, methoxypolyalkylene glycol (meth) acrylate, and ethoxypolyalkylene glycol (meth) acrylate. The surface protective film of claim 1 or 2 is used as a surface protective film for a polarizing plate.