TWI541307B - Adhesive composition and surface protection film - Google Patents

Description

Adhesive composition and surface protective film

The present invention relates to a surface protective film used in a manufacturing step of a liquid crystal display. More specifically, the present invention relates to a surface protective film for protecting a surface of an optical member such as a polarizing plate or a phase difference plate by being bonded to a surface of an optical member such as a polarizing plate or a phase difference plate constituting a liquid crystal display. A composition of the agent, and a surface protective film using the adhesive composition.

In the manufacturing process of an optical member such as a polarizing plate or a retardation film which is a member constituting a liquid crystal display, a surface protective film is attached to temporarily protect the surface of the optical member. Such a surface protective film is used only in the step of manufacturing an optical member, and when the optical member is assembled to a liquid crystal display, it is removed from the optical member and removed. Since such a surface protective film for protecting the surface of the optical member is used only in the manufacturing step, it is also generally referred to as a "step film".

In the surface protective film used in the step of producing an optical member, an adhesive layer is formed on one surface of a polyethylene terephthalate (PET) resin film having optical transparency, and A release film that has been subjected to release treatment is attached to the adhesive layer to protect the adhesive layer until it is bonded to the optical member. In addition, in an optical member such as a polarizing plate or a phase difference plate, product inspection with optical evaluation such as display performance, color tone, contrast, and impurity incorporation of the liquid crystal display panel is performed in a state in which the surface protective film is bonded, As a performance requirement for the surface protective film, it is required that the adhesive layer does not contain bubbles or impurities. In addition, when the surface protective film is peeled off from an optical member such as a polarizing plate or a retardation plate, the static electricity generated by the static electricity generated when the adhesive layer is peeled off from the adherend may be affected by the liquid crystal. The failure of the electrical control circuit of the display, therefore, requires the adhesive layer to have excellent antistatic properties. Further, when a surface protective film is bonded to an optical member such as a polarizing plate or a retardation plate, the surface protective film may be temporarily peeled off after temporarily peeling off the surface protective film for various reasons, and in this case, it is required to be easily adhered. Peeling (reworkability) on the optical member of the body. Further, when the surface protective film is finally peeled off from an optical member such as a polarizing plate or a phase difference plate, it is required to be able to be quickly peeled off. That is, it is required that the adhesion force is small due to the change in the peeling speed, so that it can be peeled off quickly even in the case of high-speed peeling.

As described above, in recent years, from the viewpoint of easy handling when using a surface protective film, it is required that the adhesive layer constituting the surface protective film has the following properties: (1) A balance of adhesion is obtained at a low peeling speed and a high peeling speed. (2) prevention of the occurrence of adhesive residue; (3) excellent antistatic properties; and (4) rework performance. However, even if the performance requirements for the adhesive layer constituting the surface protective film can be satisfied, that is, even if the individual performance requirements in the above (1) to (4) can be respectively satisfied, the adhesion of the surface protective film is required to be satisfied at the same time. The agent layer has all the performance requirements of (1) to (4), which is a very difficult problem.

For example, regarding the (1) balance of the adhesive force at a low peeling speed and a high peeling speed, and (2) prevention of the occurrence of the adhesive residue, the following proposals are known.

Acrylic acid obtained by using a copolymer of an alkyl (meth) acrylate having an alkyl group having 7 or less carbon atoms and a copolymerizable compound having a carboxyl group as a main component, and crosslinking treatment thereof with a crosslinking agent In the pressure-sensitive adhesive layer, when the adhesive is applied for a long period of time, there is a time when the adhesive moves to the adherend to adhere to the adherend, and the adhesion to the adherend is over time. The problem of rising up. In order to avoid this problem, there is known a technical solution in which an adhesive layer is used which uses an alkyl (meth)acrylate having an alkyl group having 8 to 10 carbon atoms and has an alcohol. A copolymer of a copolymer of a hydroxyl group and a pressure-sensitive adhesive layer obtained by crosslinking a crosslinking agent (Patent Document 1). Further, a technical solution is provided in which an adhesive layer is provided by mixing a small amount of an alkyl (meth) acrylate and a carboxyl group in the same copolymer as described above. A copolymer of a copolymerizable compound and an adhesive layer obtained by crosslinking it with a crosslinking agent. However, when it is used for the surface protection of a plastic plate or the like having a low surface tension and a smooth surface, there is a problem of peeling phenomenon such as separation due to heating during processing or storage, and high-speed peeling in the field of manual operation. The problem of poor removability.

In order to solve these problems, an adhesive composition is proposed which is characterized in that a) an alkyl (meth)acrylate having an alkyl group having 8 to 10 carbon atoms as a main component ( To 100 parts by weight of the alkyl (meth) acrylate, b) 1 to 15 parts by weight of a carboxyl group-containing copolymerizable compound, and c) 3 to 100 parts by weight of an ethylene carboxylic acid having 1 to 5 carbon atoms; An adhesive composition obtained by mixing a copolymer of a monomer mixture with a carboxyl group, and a crosslinking agent having a carboxyl group equivalent or more of the above b) component is added to the copolymer (Patent Document 2). In the adhesive composition described in Patent Document 2, peeling phenomenon such as separation does not occur during processing or storage, and the adhesion strength is small with time, and the removability is excellent, even for long-term storage. In particular, it can be re-peeled with a small force even after long-term storage in a high-temperature environment. At this time, no adhesive remains on the adherend, and even with high-speed peeling, it can be performed with a small force. Strip again.

In addition, as a method for imparting antistatic properties to the surface protective film, (3) excellent antistatic performance, a method of mixing an antistatic agent into a base film, or the like has been proposed. As the antistatic agent, for example, various cationic antistatic agents of (a) a 4-grade ammonium salt, a pyridinium salt, a cationic group having a primary to tertiary amine group, and the like; (b) a sulfonate group and a sulfate salt are disclosed. Anionic antistatic agent such as an anion group such as a phosphate group, a phosphonate group or a phosphonate group; (c) an amphoteric antistatic agent such as an amino acid or an amine sulfate; (d) an amino alcohol or a glycerin And a nonionic antistatic agent such as a polyethylene glycol; (e) a polymer type antistatic agent obtained by polymerizing the antistatic agent as described above (Patent Document 3). Further, in recent years, it has been proposed to incorporate such an antistatic agent directly into the adhesive layer, instead of being included in the substrate film or applied to the surface of the substrate film.

Further, regarding (4) reworkability, for example, an adhesive composition is proposed in which 0.0001 to 10 parts by weight of an isocyanate compound is cured with respect to 100 parts by weight of the acrylic resin. It is obtained by the agent and a specific phthalate oligomer (patent document 4). Patent Document 4 describes, as a main monomer, an alkyl acrylate having an alkyl group having a carbon number of from 2 to 12, an alkyl methacrylate having an alkyl group having a carbon number of from 4 to 12, or the like. The component may contain, for example, a monomer component containing other functional groups such as a carboxyl group-containing monomer. In general, it is preferred to contain 50% by weight or more of the above-mentioned main monomer, and it is desirable that the content of the functional group-containing monomer component is 0.001 to 50% by weight, preferably 0.001 to 25% by weight, more preferably 0.01 to 25% by weight. %. The adhesive composition described in Patent Document 4 has a small change in the cohesive force and the adhesive force over time even under high temperature or high temperature and high humidity, and exhibits an excellent effect on the adhesion to the curved surface. Reworkability. In general, when the pressure-sensitive adhesive layer is in a soft property, the adhesive remains easily, and the reworkability is also likely to be lowered. That is, it is difficult to peel again after the wrong bonding, and it is difficult to re-stick. From this point of view, in order to impart reworkability, it is necessary to crosslink a monomer having a functional group such as a carboxyl group to the main component so that the adhesive layer has a certain hardness. [Prior Art Literature] [Patent Literature]

Japanese Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei.

[Problems to be solved by the invention]

In the prior art, as a performance requirement for an adhesive layer constituting a surface protective film, it has been conventionally required to achieve a balance of adhesion at a low peeling speed and a high peeling speed, and to have excellent antistatic properties and rework. Performance, etc. However, even if the performance requirements can be individually satisfied, all the performance requirements required for the adhesive layer as the surface protective film cannot be satisfied.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a paste having excellent antistatic properties, excellent balance of adhesion at a low peeling speed and a high peeling speed, and excellent durability and reworkability. The composition of the agent and the surface protective film. [Method of solving the problem]

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(meth)acrylate monomer, and E) an acrylic polymer of a copolymer of at least one of a group of copolymerizable monomers comprising a hydroxyl group-containing vinyl monomer or an alkoxy-containing alkyl (meth)acrylate monomer, Further, it further contains (F) a trifunctional or higher isocyanate compound, (G) a difunctional acyclic aliphatic isocyanate compound, and (H) an antistatic agent.

Further, when the total amount of the acrylic polymer of the copolymer is 100 parts by weight, it is preferred that the (A) alkyl group has a C4 to C18 (meth) acrylate monomer content. 50 to 91 parts by weight, the content of the (B) hydroxyl group-containing copolymerizable monomer is 0.1 to 10 parts by weight, and the content of the (C) carboxyl group-containing copolymerizable monomer is 0 to 1.0 part by weight, the above (D) a polyalkylene glycol mono(meth)acrylate monomer content of 0 to 50 parts by weight, the above (E) a hydroxyl group-free nitrogen-containing vinyl monomer or an alkoxy group-containing (methyl) group The content of the alkyl acrylate monomer is from 0 to 20 parts by weight.

Further, the weight ratio (F/G) of the (F) trifunctional or higher isocyanate compound to the (G) difunctional acyclic aliphatic isocyanate compound is from 1 to 90, relative to 100 parts by weight of the acrylic polymer. The total amount of the above-mentioned (F) trifunctional or higher isocyanate compound and (G) difunctional acyclic aliphatic isocyanate compound is preferably 0.1 to 5.0 parts by weight.

Further, the (G) difunctional acyclic aliphatic isocyanate compound is a compound produced by reacting a diisocyanate compound with a diol compound. The diisocyanate compound is an aliphatic diisocyanate, preferably selected from the group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene group. It is composed of one of a compound group composed of an isocyanate and an isocyanuric 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, 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, it is preferred that the (D) polyalkylene glycol mono(meth)acrylate monomer is selected from the group consisting of polyalkylene glycol mono(meth)acrylates and methoxypolyalkylene glycols ( At least one of methyl acrylate and ethoxypolyalkylene glycol (meth) acrylate.

The above-mentioned (F) trifunctional or higher isocyanate compound is preferably an isocyanurate or an hexamethylene group selected from the group consisting of isocyanurate and isophorone diisocyanate compounds derived from a hexamethylene diisocyanate compound. An adduct of an isocyanate compound, an adduct of an isophorone diisocyanate compound, a biuret of a hexamethylene diisocyanate compound, a biuret of an isophorone diisocyanate compound, and an isocyanide of a toluene diisocyanate compound Isocyanurate, isocyanurate of benzodimethyl diisocyanate compound, isocyanurate of hydrogenated dimethylated diisocyanate compound, adduct of toluene diisocyanate compound, benzene diisocyanate compound At least one or more of the compound group consisting of the adduct and the adduct of the hydrogenated dimethylene diisocyanate compound.

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

Further, it is preferable that the (H) antistatic agent is an ionic compound containing 0.01 to 5.0 parts by weight and a melting point of 30 to 50 ° C with respect to 100 parts by weight of the copolymer, or a copolymerization amount in the copolymer 0.1 to 5.0% by weight of an ionic compound containing an acrylonitrile group.

Further, it is preferred that the adhesive layer obtained by crosslinking the pressure-sensitive 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 high peeling speed of 30 m/min. The adhesion is 1.0 N/25 mm or less.

Further, it is preferable that the adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition has a surface resistivity of 5.0 × 10 ^{+ 10} Ω / □ or less and a peeling static voltage of ± 0 to 1 kV.

Further, the present invention provides a surface protective film comprising an adhesive layer formed on one surface or both surfaces of a resin film, wherein the pressure-sensitive adhesive layer is formed by crosslinking the pressure-sensitive adhesive composition.

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 preferred that an antistatic treatment and an antifouling treatment are performed on a surface of the resin film opposite to a side on which the adhesive layer is formed. [effect of the invention]

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, and it is possible to obtain excellent antistatic properties and prevent the occurrence of the adhesive 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. In addition, by using (F) a trifunctional or higher isocyanate compound and (G) a difunctional acyclic aliphatic isocyanate compound in combination, it is possible to obtain excellent crosslinkability and good stain resistance, and further at a low peeling speed and The balance of the adhesive force at a high peeling speed is excellent.

Hereinafter, the present invention will be described based on preferred embodiments. 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 (C) alkyl group 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 An acrylic polymer comprising a copolymer of at least one of a hydroxyl group-containing vinyl monomer or an alkoxy group-containing (meth)acrylic acid alkyl ester monomer; Further, the pressure-sensitive adhesive composition further contains (F) a trifunctional or higher isocyanate compound, (G) a difunctional acyclic aliphatic isocyanate compound, and (H) an antistatic agent. Further, when the total amount of the acrylic polymer of the copolymer is 100 parts by weight, it is preferably 50 to 91 parts by weight of the (A) alkyl group having a C4 to C18 carbon number. An 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) poly Asian An alkyl diol mono(meth) acrylate monomer, 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 single ester body.

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 (meth)acrylate, isostearyl (meth)acrylate, and the like. When the total amount of the acrylic polymer of the copolymer is 100 parts by weight, the (A) alkyl group has a C4 to C18 (meth) acrylate monomer content of 50 to 91% by weight. Share.

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

Preferably, 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)acrylic acid. Oxyethylhexahydrophthalic acid, 2-(methyl)propenyloxypropylhexahydrophthalic acid, 2-(methyl)acryloxyethyl phthalate, 2-( Methyl) propylene methoxyethyl succinic acid, 2-(methyl) propylene oxiranyl ethyl maleic acid, carboxy polycaprolactone mono (meth) acrylate, 2-(methyl) propylene oxime At least one or more of the compound groups consisting of chloroethyltetrahydrophthalic acid. 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. Preferably, the average number of repetitions of the alkylene oxide constituting the polyalkylene glycol chain in the (D) polyalkylene glycol mono(meth)acrylate monomer 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)acrylate, methoxypolyalkylene glycol (methyl) 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 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 also contain no (D) 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-vinylpiperidin, N-vinylpyridinium, 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)propenylhydrazide, N-(methyl)propenyl aziridine, N-(methyl)propenylpyridinium, N-(methyl)acrylonitrile Pyrrolidine, N-(methyl)propenylpyridylpiperidine, N-(methyl)propenylfluorenyl azepane, N-(methyl)propenyl aziridine, etc. having N-( a cyclic nitrogen-nitrogen compound having a methylidene-substituted fluorenyl group; N-cyclohexylmaleimine, N-phenylmaleimide, etc. having a nitrogen atom and a vinyl group in the ring a cyclic nitrogen-vinyl compound of a heterocyclic structure having an unsaturated bond; (meth) acrylamide, N-methyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N- Unsubstituted or monoalkyl-substituted (meth) acrylamide such as 3-butyl (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, N-methyl-N-isopropyl(methyl)propene oxime Dialkyl substituted (meth) propyl Indoleamine; 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-diethyl Aminomethyl (meth) 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-dibutylamino Dialkylamino (meth) acrylate such as ethyl (meth) acrylate or 3-butylaminoethyl (meth) acrylate; N, N-dimethylaminopropyl (methyl) Acrylamide, N,N-diethylaminopropyl (meth) acrylamide, N,N-dipropylaminopropyl (meth) acrylamide, N,N-diisopropyl Aminopropyl (meth) acrylamide, N-ethyl-N-methylaminopropyl (meth) acrylamide, N-methyl-N-propylaminopropyl (methyl N,N- such as acrylamide, N-methyl-N-isopropylaminopropyl (meth) acrylamide Dialkyl substituted aminopropyl (meth) acrylamide; N-vinyl carbamide, N-vinyl acetamide, N-vinyl acetamide, N-vinyl ketamine Acid amides; N-methoxymethyl (meth) acrylamide, N-ethoxyethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, (meth) acrylamide such as diacetone acrylamide or N,N-methylenebis(methyl) acrylamide; unsaturated carboxylic acid nitriles such as (meth)acrylonitrile;

The (E-1) nitrogen-containing vinyl monomer preferably contains no hydroxyl group, and more preferably contains no hydroxyl group or carboxyl group. As such a monomer, it is preferably a monomer exemplified above, for example, an acrylic monomer containing an N,N-dialkyl substituted amine group, an N,N-dialkyl substituted guanamine group; N-vinyl group- 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 (A) The content of the alkyl acrylate monomer is from 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) trifunctional or higher isocyanate compound may be at least one or two or more selected from the group consisting of polyisocyanate compounds having at least three 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 diisocyanate (a compound having two NCO groups in one molecule), and a trimethylol 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 propane (TMP) or glycerin. The (F) trifunctional or higher isocyanate compound is preferably contained in an amount of 0.5 to 5.0 parts by weight based on 100 parts by weight of the copolymer.

Further, the (F) trifunctional or higher isocyanate compound used in the present invention preferably includes at least one selected from the group consisting of (F-1) a first aliphatic isocyanate compound and selected from (F-2). At least one or more of the group of the second aromatic isocyanate compounds, wherein the (F-1) first aliphatic isocyanate compound group is an isocyanurate or isophorone derived from a hexamethylene diisocyanate compound Isocyanurate of an isocyanate compound, an adduct of a hexamethylene diisocyanate compound, an adduct of an isophorone diisocyanate compound, a biuret of a hexamethylene diisocyanate compound, isophorone The biuret of the diisocyanate compound is composed; the (F-2) second aromatic isocyanate compound group is an isocyanurate of a toluene diisocyanate compound, an isocyanurate of a benzene dimethyl diisocyanate compound. An isocyanurate of a hydrogenated dimethylenedi-isocyanate compound, an adduct of a toluene diisocyanate compound, an adduct of a benzenedimethyl diisocyanate compound, or a hydrogenated benzyl dichloride Cyanate compound adduct composed. Preferably, the (F-1) first aliphatic isocyanate compound group and the (F-2) second aromatic isocyanate compound group are used in combination. In the present invention, as the (F) trifunctional or higher isocyanate compound, at least one selected from the group consisting of (F-1) a first aliphatic isocyanate compound and a second aromatic selected from (F-2) are used in combination. At least one or more of the group of isocyanate compounds can further improve the balance of the adhesion in the low-speed peeling region and the high-speed peeling region. Further, preferably, the (F) trifunctional or higher isocyanate compound includes at least one selected from the group consisting of the above (F-1) first aliphatic isocyanate compound group and a second aromatic group selected from the above (F-2). At least one or more of the 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. In addition, as a mixing ratio of at least one or more selected from the group consisting of (F-1) the first aliphatic isocyanate compound group and at least one selected from the group consisting of (F-2) second aromatic isocyanate compound, The ratio calculation should be (F-1): (F-2) in the range of 10%: 90% to 90%: 10%.

Further, the (G) difunctional acyclic aliphatic isocyanate compound used in the present invention is an acyclic compound which is an aliphatic compound among the difunctional isocyanate compounds. The (G) difunctional acyclic aliphatic isocyanate compound is preferably 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=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 (G) 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 it is preferable that n is 1 or more as an essential component. An integer compound. The (G) difunctional acyclic aliphatic isocyanate compound may also be a mixture of a plurality of compounds different from n in the formula Z.

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 lysine. One or two or more of the compound groups consisting of diisocyanates are used.

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-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.

The weight ratio (F/G) of the above (F) trifunctional or higher isocyanate compound to (G) difunctional acyclic aliphatic isocyanate compound is from 1 to 90. The total amount of the (F) trifunctional or higher isocyanate compound and the (G) difunctional acyclic aliphatic isocyanate compound is preferably 0.1 to 5.0 parts by weight based on 100 parts by weight of the acrylic polymer.

Preferably, the (H) antistatic agent is (H-1) an ionic compound having a melting point of 30 to 50 ° C or (H-2) an ionic compound containing an acrylonitrile group. In the present invention, as the (H) antistatic agent, (H-1) an ionic compound having a melting point of 30 to 50 ° C is added to the copolymer, or (H-2) an ionic compound containing an acrylonitrile group. Copolymerized in the copolymer. It is presumed that since these (H) antistatic agents have a low melting point and a long-chain alkyl group, they have high affinity with an acrylic copolymer.

The ionic compound having a (H-1) melting point of 30 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 ₄ SO ₃ ^-), perchlorate (ClO ₄ ^- compound) of an inorganic or organic anion ^-), tetrafluoroborate (BF _4. It is preferably a solid at normal temperature (for example, 30 ° C), and a compound having a melting point of 30 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. Preferably, the cation is a 4-stage hydrazine cation, and a 4-stage pyridinium cation such as 1-alkylpyridinium (having a substituent or a substituent at a 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-stage ammonium cation such as a tetraalkylammonium. The content of the ionic compound having a (H-1) melting point of 30 to 50 ° C is preferably 0.01 to 5.0 parts by weight based on 100 parts by weight of the copolymer.

As the ionic compound (H-2) containing Bingxi Xi group, an ionic compound having a cation and an anion, include: cationic (meth) Bing Xixi trialkyl ammonium (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 (H-2) ionic compound containing an acrylonitrile group is preferably copolymerized in the copolymer in an amount of from 0.1 to 5.0% by weight.

Specific examples of the (H) antistatic agent are not particularly limited, and specific examples of the (H-1) ionic compound having a melting point of 30 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 (H-2) ionic compound containing an acryloyl 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 a polyether modified siloxane compound. The polyether-modified siloxane compound is a siloxane compound having a polyether group, and has, in addition to the usual siloxane unit (-SiR ¹ ₂ -O-), a siloxane unit containing a polyether group. (-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 include: polyoxyethylene _{((C 2 H 4 O)} n) or a polyoxypropylene group _{((C 3 H 6 O)} n) like polyoxyalkylene. Preferably, the polyether modified siloxane compound is a polyether modified siloxane compound having an HLB value of from 7 to 12. Further, the content of the polyether-modified siloxane compound is preferably 0.01 to 0.5 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 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. Obtained from the main chain of the alkane. 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, or the like. By blending the 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.

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 C1-C18 (meth) acrylate monomer having an alkyl group having an alkyl group. From (B) hydroxyl group-containing copolymerizable monomer, (C) carboxyl group-containing copolymerizable monomer, (D) polyalkylene glycol mono(meth)acrylate monomer as a copolymerizable monomer group It is synthesized by copolymerizing at least one of (E) a hydroxyl group-free nitrogen-containing vinyl monomer or an alkoxy group-containing (meth)acrylic acid alkyl ester monomer. 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 (H-2) an acryl-containing ionic compound is used as the (H) antistatic agent, the copolymer of the main component used as the adhesive composition of the present invention can be obtained by (A) an alkyl group. At least one of C4 to C18 (meth) acrylate monomers having a carbon number is selected from (B) a hydroxyl group-containing copolymerizable monomer selected from the group of copolymerizable monomers, and (C) a carboxyl group Copolymerizable monomer, (D) polyalkylene glycol mono(meth)acrylate monomer, and (E) hydroxyl-free nitrogen-containing vinyl monomer or alkoxy-containing (meth)acrylic acid At least one of the copolymerizable monomer groups composed of the alkyl ester monomers and the (H-2) acryl-containing ionic group-containing ionic compound are copolymerized to be synthesized. The adhesive composition of the present invention may be prepared by blending (F) a trifunctional or higher isocyanate compound, (G) a difunctional acyclic aliphatic isocyanate compound, (H) an antistatic agent, and the like in the above copolymer. Any of the additives to prepare. Further, when (H-2) an ionic compound containing an acrylonitrile group has been polymerized in the main copolymer, the (H) antistatic agent may be further added to the copolymer, or may not be added (H). ) Antistatic agent.

Preferably, the copolymer is an acrylic polymer, preferably containing 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 from 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 preferred 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. It is 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.

Preferably, the adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition has a surface resistivity of 5.0 × 10 ^{+ 10} Ω / □ or less and a peeling static voltage of ± 0 to 1 kV. Further, in the present invention, the term "±0 to 1 kV" means "0 to -1 kV" and "0 to +1 kV", that is, "-1 to +1 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 preferred 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 or both surfaces 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 (H) described above are blended with good balance, they have excellent antistatic properties, and are sticky at a low peeling speed and a 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 preferably 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. The base film can be formed on the surface of the resin film opposite to the side on which the pressure-sensitive adhesive layer is formed by an anthrone or a fluorine-based release agent, a coating agent, cerium oxide particles or the like. The antifouling treatment can be carried out by an antistatic treatment by coating 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 an acrylic acid used in 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 9 and Comparative Examples 1 to 4] The above examples were used except that the compositions of the respective monomers were adjusted as described above in (A) to (E) and (H-2) in Table 1. The acrylic copolymer solution 1 of 1 was similarly operated, and the acrylic copolymer solutions used in Examples 2 to 9 and Comparative Examples 1 to 4 were obtained.

【Table 1】

<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 was added and carried out. After stirring, 2.0 parts by weight of Coronate HX (isocyanurate of hexamethylene diisocyanate compound) and 0.5 part by weight of difunctional acyclic aliphatic isocyanate compound G-1 of Synthesis Example 1 were added, followed by stirring and mixing, and obtained The adhesive composition of Example 1. 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 has 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 9 and Comparative Examples 1 to 4] The operation was carried out in the same manner as in the surface protective film of Example 1 except that the composition of each additive was adjusted as described above in (F) to (H) of Table 2, The surface protective films of Examples 2 to 9 and Comparative Examples 1 to 4 were obtained.

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 weight 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. 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, D -110N, D-120N is the trade name of Mitsui Chemicals Co., Ltd. In Table 1, (H-2) an acrylonitrile-containing quaternary ammonium salt type ionic compound copolymerized in a copolymer (H) and a (H) antistatic agent added after polymerization in the antistatic agent , respectively, are recorded in different columns.

【table 3】

【Table 4】

<Synthesis of Difunctional Acyclic Aliphatic Isocyanate Compound> The difunctional acyclic aliphatic isocyanate compounds of Synthesis Examples 1 to 3 were synthesized by the following methods. As shown in Table 5 and Table 6, the diisocyanate was mixed with the diol compound at a molar ratio of NCO/OH=16, and reacted at 120 ° C for 3 hours, and then unreacted under reduced pressure by a thin film evaporation apparatus. The diisocyanate gives the desired difunctional acyclic aliphatic isocyanate compound.

<Test method and evaluation> After the surface protective films of Examples 1 to 9 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 allowing to stand at room temperature for 12 hours for 20 minutes, it was used as a sample for measuring adhesion, peeling static voltage, reworkability, and durability.

<Adhesion force> The above-obtained measurement sample was peeled off in a 180° direction at a low peeling speed (0.3 m/min) and a high peeling speed (30 m/min) using a tensile tester (a 25 mm-wide surface protective film was used). The sample which was bonded to the surface of the polarizing plate was measured, and the peeling strength was measured, and this peeling strength was used as an adhesive force.

<Surface resistivity> After aging, before peeling off the polarizing plate, peeling off the peeling film (PET film coated with an oxime resin) to expose the adhesive layer, using a resistivity meter HirestaUP-HT450 (Mitsubishi Chemical Analysis Technology ( The company was manufactured by Mitsubishi Chemical Analytech Co., Ltd., and the surface resistivity of the adhesive layer was measured.

<Peel static voltage> Using a high-precision electrostatic sensor SK-035, SK-200 (manufactured by Keyence Corporation), the measurement sample obtained above was pulled at 30 m/min. When the stretching speed is 180° 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: 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 polarizing plate transfers the contamination. 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.

<Durability> The measurement sample obtained above was placed in an environment of 60° C. and 90% RH for 250 hours, and then taken out and left at room temperature for further 12 hours, and then the adhesion was measured to confirm the initial adhesion. Compare whether there is a significant 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).

[Table 7]

The surface protective films of Examples 1 to 9 had 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 of 1.0 N/25 mm or less. The surface resistivity is 5.0×10 ⁺¹⁰ Ω/□ or less, and the peeling static voltage is ±0 to 1 kV; and after the surface protective film is drawn through the adhesive layer with a ball pen, there is no adhering body. The contamination was transferred, and the durability after leaving it for 250 hours in an environment of 60 ° C and 90% RH was also excellent. That is, all of the following performance requirements are satisfied: (1) achieving balance of adhesion at low peeling speed and high peeling speed; (2) preventing occurrence of adhesive residue; (3) excellent antistatic property; And (4) reworkability.

The surface protective film of Comparative Example 1 may have a low exfoliation because it does not contain (F) a trifunctional or higher isocyanate compound and a (G) difunctional acyclic aliphatic isocyanate compound as a crosslinking agent. The adhesive force at a speed of 0.3 m/min and a high peeling speed of 30 m/min was too large, the surface resistivity and the peeling static voltage were high, and the workability and durability were poor. The surface protective film of Comparative Example 2 does not contain a (G) difunctional acyclic aliphatic isocyanate compound, but contains a uretdione ring-containing diisocyanate compound as a difunctional cyclic isocyanate compound. It has an excessively high adhesion at a high peeling speed of 30 m/min and poor durability. The surface protective film of Comparative Example 3 may be because the (F) trifunctional or higher isocyanate compound is too large and does not contain the (G) difunctional acyclic aliphatic isocyanate compound, and the storage period is too short. Crosslinking has been carried out before, so coating is not possible. The surface protective film of Comparative Example 4 may be because the (G) difunctional acyclic aliphatic isocyanate compound is more than (F) trifunctional or higher isocyanate compound, and it is at a high peeling speed of 30 m/min. Excessive adhesion and poor durability. As described above, in the surface protective films of Comparative Examples 1 to 4, it is not possible to satisfy all of the following performance requirements: (1) achieving a balance between the low peeling speed and the adhesive force at a high peeling speed; and (2) preventing the adhesive Residual occurrence; (3) excellent antistatic properties; and (4) reworkability.

Claims (14)

An adhesive composition comprising: at least one of a (meth) acrylate monomer having a CA to C18 carbon number of (A) alkyl group, and selected from the group consisting of copolymerizable monomers (B) hydroxyl group-containing copolymerizable monomer, (C) carboxyl group-containing copolymerizable monomer, (D) polyalkylene glycol mono(meth)acrylate monomer, and (E) hydroxyl group-free nitrogen-containing An acrylic polymer of a copolymer of at least one of a vinyl monomer or an alkoxy-containing alkyl (meth) acrylate monomer, and further comprising (F) three a functional or higher isocyanate compound, (G) a difunctional acyclic aliphatic isocyanate compound, and (H) an antistatic agent, the (F) trifunctional or higher isocyanate compound and (G) a difunctional acyclic aliphatic isocyanate compound The weight ratio F/G is 1~90. The adhesive composition of claim 1, wherein when the total amount of the acrylic polymer of the copolymer is 100 parts by weight, the (A) alkyl group has a C4 to C18 carbon number. The content of the (meth) acrylate monomer is 50 to 91 parts by weight, and the content of the (B) hydroxyl group-containing copolymerizable monomer is 0.1 to 10 parts by weight, and the content of the (C) carboxyl group-containing copolymerizable monomer The content of the (D) polyalkylene glycol mono(meth)acrylate monomer is 0 to 50 parts by weight, and the (E) vinyl group containing no hydroxyl group and containing nitrogen is 0 to 1.0 part by weight. Or the content of the alkoxy-containing alkyl (meth)acrylate monomer is 0 to 20 parts by weight. The adhesive composition according to claim 1 or 2, wherein the (F) trifunctional or higher isocyanate compound and (G) difunctional acyclic aliphatic group are relative to 100 parts by weight of the acrylic polymer. The total amount of the isocyanate compounds is from 0.1 to 5.0 parts by weight. The adhesive composition according to claim 1 or 2, wherein the (G) difunctional acyclic aliphatic isocyanate compound is a compound formed by reacting a diisocyanate compound with a diol compound, the diisocyanate compound Is an aliphatic diisocyanate and is selected from the group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethyl hexamethylene diisocyanate, and diazonic acid diisocyanate. The diol compound is 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 - one of a group of compounds consisting of propylene glycol monohydroxy pivalate, polyethylene glycol, and polypropylene glycol. The adhesive composition according to claim 1 or 2, wherein the (B) hydroxyl group-containing copolymerizable monomer is selected from the group consisting of 8-hydroxyoctyl (meth)acrylate and (meth)acrylic acid. 6-hydroxyhexyl ester, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, N-hydroxy(meth)acrylamide, N-hydroxymethyl(meth)acryl At least one or more of the compound group consisting of an amine and N-hydroxyethyl (meth) acrylamide 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)acryloxyloxy group. 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 adhesive composition of claim 1 or 2, wherein the (D) polyalkylene glycol mono(meth)acrylate monomer is selected from the group consisting of polyalkylene glycol mono (methyl) At least one of acrylate, methoxypolyalkylene glycol (meth) acrylate, and ethoxypolyalkylene glycol (meth) acrylate. The adhesive composition according to claim 1 or 2, wherein the (F) trifunctional or higher isocyanate compound is selected from the group consisting of isocyanurate and hexamethyl diisocyanate compounds. Isocyanurate of an ketone diisocyanate compound, an adduct of a hexamethylene diisocyanate compound, an adduct of an isophorone diisocyanate compound, a biuret of a hexamethylene diisocyanate compound, and a different Buddha Biuret of a ketone diisocyanate compound, isocyanurate of a toluene diisocyanate compound, isocyanurate of a benzene dimethyl diisocyanate compound, isocyanurate of a hydrogenated dimethyl dimethyl diisocyanate compound, At least one or more of the compound group consisting of the adduct of the toluene diisocyanate compound, the adduct of the benzodimethyl diisocyanate compound, and the adduct of the hydrogenated dimethyl diisocyanate compound. An adhesive composition according to claim 1 or 2, wherein the acrylic polymer as the copolymerizable monomer group contains the above (E) a hydroxyl group-free nitrogen-containing vinyl monomer or an alkoxy group. At least one or more of the alkyl (meth) acrylate monomers. The adhesive composition according to claim 1 or 2, wherein the (H) antistatic agent is an ion having 0.01 to 5.0 parts by weight and a melting point of 30 to 50 ° C with respect to 100 parts by weight of the copolymer. The compound is an ionic compound containing an acrylonitrile group in an amount of 0.1 to 5.0% by weight in the copolymer. 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 at a low peeling speed of 0.3 m/min. N/25 mm, the adhesion at a high peeling speed of 30 m/min is 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 5.0 × 10 ^{+ 10} Ω / □ or less and is peeled off. The static voltage is ±0~1kV. A surface protective film which is formed by forming an adhesive layer on one side or both sides of a resin film, the adhesive layer being an adhesive composition according to any one of claims 1 to 11. Cross-linked. The surface protective film of claim 12 is used as a surface protective film for a polarizing plate. The surface protective film of claim 13, 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.