TWI830809B - Adhesive composition, and adhesive film, surface-protective film using the same - Google Patents

Abstract

The present invention provides an adhesive composition, and an adhesive film and a surface-protecting film using the same. The adhesive composition, and the adhesive film and the surface-protecting film using the same have a balanced adhesion property at a low peeling speed and a high peeling speed, and achieve both an antistatic property and an anti-contamination property at the same time. The acrylic polymer contains 2-ethylhexyl acrylate in a ratio of 50 parts by weight or more, and at least one of a monofunctional methacrylate monomer having a Tg of 0°C or higher in a ratio of 5 to 40 parts by weight, and the acrylic polymer is copolymerized by total 100 parts in total by weight of at least two of (A) an alkyl (meth)acrylic acid ester monomer having a C1 to C10 alkyl group, 1.0 to 6.0 parts by weight of (B) a copolymerizable monomer containing a hydroxyl group , and 1.0 to 6.0 parts by weight of (C) a copolymerizable monomer containing an carboxyl group. The acrylic polymer has an acid value of 0.1 to 1.0 and a weight average molecular weight of more than 300,000 and less than 1,000,000.

Description

Adhesive composition and adhesive film and surface protective film using the same

The present invention relates to an adhesive composition that can be applied to a surface protective film such as a surface protective film for a polarizing plate, an adhesive film and a surface protective film using the adhesive composition. More specifically, it relates to an adhesive composition having balanced adhesion at a low peeling speed and a high peeling speed, and an adhesive film and a surface protective film using the same. strength, and at the same time, it can achieve both antistatic performance and anti-pollution performance.

Conventionally, in the manufacturing process of optical members such as polarizing plates that are components of a liquid crystal display, a surface protective film has been bonded to temporarily protect the surface of the optical member. Such a surface protective film is used only in the process of manufacturing an optical member, and when the optical member is mounted on a liquid crystal display, it is peeled off and removed from the optical member. Since this kind of surface protection film used to protect the surface of optical components is only used during the manufacturing process of optical components, it is often also called a process film.

This type of surface protection film used in the process of manufacturing optical components has a structure in which an adhesive layer is provided on one side of an optically transparent polyethylene terephthalate (PET) resin film. In addition, before being bonded to the optical member, in order to protect the adhesive layer, a release film that has been subjected to release processing is bonded to the surface of the adhesive layer of the surface protective film. In addition, optical components such as polarizing plates are subjected to product inspections involving optical evaluation of display capabilities, color tone, contrast, inclusion of impurities, etc. of liquid crystal display panels in a state where surface protective films are bonded to them. Therefore, as performance requirements for the surface protection film, it is required that the adhesive layer does not contain air bubbles or impurities, and that it can reduce the adhesion of low molecular weight components of the adhesive composition to the surface of the adherend, that is, it is required to have anti-pollution properties. In addition, when peeling off a surface protective film from an optical component such as a polarizing plate, the peeling static electricity caused by the static electricity generated when peeling off the adhesive layer from the adherend may cause a malfunction of the electrical control circuit of the liquid crystal display. Therefore, the adhesive layer of the surface protective film is required to have excellent antistatic properties. Furthermore, in recent years, in addition to triacetylcellulose (TAC) that has been used conventionally as a protective layer (sometimes called a protective film) for polarizers of polarizers, polymethylmethacrylate (PMMA) has been increasingly used Materials such as acrylic resins, polyester resins such as polyethylene terephthalate (PET), cyclic olefin polymers, polycarbonates, etc., which tend to generate peeling static electricity when peeling off the surface protective film of the polarizing plate use. Therefore, the antistatic performance required for the adhesive layer used in the surface protective film of the polarizing plate needs to be better than ever before. In addition, when the surface protective film is finally peeled off from an optical member such as a polarizing plate, it is required to be able to peel it off quickly. In other words, even if the peeling speed changes, the change in the adhesive force is required to be small, so that even in the case of high-speed peeling, it can be peeled off quickly.

As mentioned above, in recent years, from the perspective of ease of use when using a surface protective film, the adhesive layer constituting the surface protective film is required to have the following properties: (1) Obtain adhesion at a low peeling speed and a high peeling speed Balance of forces; (2) Anti-pollution properties; (3) Excellent anti-static properties. However, regarding the performance requirements for the adhesive layer constituting the surface protective film, even if the individual performance requirements (1) to (3) above can be satisfied respectively, the requirements for the adhesive layer of the surface protective film (1) to (1) to (3) can be satisfied at the same time. The full performance requirements of (3) are also very difficult technical issues.

In order to solve such technical problems, for example, (1) achieving a balance of adhesive force at low and high peeling speeds, (2) having anti-pollution properties, and (3) having excellent antistatic properties, respectively, have been I know the following plan.

Regarding (1) achieving a balance of adhesive force between a low peeling speed and a high peeling speed, it is known to use a copolymer of an alkyl (meth)acrylate having an alkyl group with 7 or less carbon atoms and a carboxyl group. It is an acrylic adhesive layer made of a copolymer of a chemical compound as the main component and cross-linked with a cross-linking agent. However, with such an adhesive layer, if the adhesive layer is adhered for a long time, the adhesive may move toward the adherend, or the adhesive force to the adherend may increase significantly over time. In order to avoid this problem, an adhesive layer using an alkyl (meth)acrylate having an alkyl group with 8 to 10 carbon atoms and a surface protection member provided with the adhesive layer are known. An adhesive layer with a gel fraction of 60% or more is obtained by cross-linking a copolymer with a copolymerizable compound having an alcoholic hydroxyl group using a cross-linking agent (Patent Document 1). However, the adhesive layer described in Patent Document 1 cannot completely solve the problem that the adhesive force to the adherend increases due to changes over time. In addition, there is known a technical solution in which an adhesive layer is provided in which a small amount of alkyl (meth)acrylate and a carboxyl-containing copolymer are blended into the same copolymer. The copolymer of the compound is cross-linked with a cross-linking agent to form an adhesive layer. However, when these adhesive layers are used to protect the surface of plastic sheets with low surface tension and smooth surfaces, there is still a problem of peeling off such as floating due to heating during processing or storage. In the field of manual operation, The problem of poor re-peelability is the problem of increased adhesion at high peeling speeds.

In order to solve these problems, an adhesive composition is proposed which contains a) alkyl (meth)acrylate having an alkyl group with 8 to 10 carbon atoms as a main component. To 100 parts by weight, add 1 to 15 parts by weight of b) a carboxyl group-containing copolymerizable compound and 3 to 100 parts by weight of c) the vinyl ester of an aliphatic carboxylic acid with 1 to 5 carbon atoms to form a monomer mixture. The copolymer is a copolymer, and a crosslinking agent is blended into the copolymer in an amount equal to or more than the carboxyl group of component b) (Patent Document 2). The adhesive layer formed by cross-linking the adhesive composition described in Patent Document 2 does not cause peeling phenomena such as floating during processing or storage, has a small increase in adhesive force over time, and has excellent removability. , even if it is stored for a long time, especially in a high temperature atmosphere, it can be peeled off again with a small force. At this time, no residual glue will be produced on the adherend, and even when peeled off at a high speed, it can be peeled off with a small force. Use force to peel off again. However, regarding the adhesive layer formed by cross-linking the adhesive composition described in Patent Document 2, the gel fraction of the adhesive layers of Examples 1 to 3 was all 90%, and the adhesion at a low peeling speed was The force is easily too great, so unpolymerized monomers or oligomers are easily eluted from the adhesive layer. In addition, Patent Document 2 does not describe antistatic properties and anti-pollution properties. When a material that easily generates peeling static electricity is used as an adherend, it is difficult to improve the adhesive to have excellent antistatic properties and anti-pollution properties. Agent layer problem.

In addition, regarding (2) having anti-pollution properties, an adhesive composition is disclosed, which contains: 100 parts by mass of a (meth)acrylic copolymer with a weight average molecular weight of 100,000 or more and less than 1,000,000. The acrylic copolymer consists of more than 0 and less than 0.5 parts by mass of carboxyl-containing monomers, 0.6 to 9 parts by mass of hydroxyl-containing (meth)acrylic monomers, and 99.4 to 90.5 parts by mass of (methyl) It is composed of acrylate monomer; and 0.1 to 5 parts by mass of carbodiimide cross-linking agent (Patent Document 3). The adhesive composition described in Patent Document 3 is characterized by using a carbodiimide cross-linking agent as a cross-linking agent for a (meth)acrylic copolymer of a specific composition. This makes it possible to provide an adhesive layer having a crosslinked structure that can follow shrinkage caused by pressure and temperature during autoclaving. Therefore, the adhesive layer formed using the adhesive composition described in Patent Document 3 can suppress and prevent bubbling even under high-temperature and high-pressure conditions (during autoclave treatment), has excellent anti-fouling performance, and is also excellent in transparency. However, although the anti-fouling performance of the adhesive layer cross-linked by cross-linking the adhesive composition described in Patent Document 3 has been improved, it has not been possible to achieve adhesive strength at a low peeling speed and a high peeling speed. There are still technical problems that need to be further solved in order to balance the excellent adhesive properties and antistatic properties.

In addition, regarding (3) having excellent antistatic properties, as a method for imparting antistatic properties to a surface protective film, a method of kneading an antistatic agent into a base film and the like are known. As antistatic agents, for example, (a) various cationic antistatic agents having cationic groups such as quaternary ammonium salts, pyridinium, and primary to tertiary amine groups are disclosed; (b) cationic antistatic agents having a sulfonate group , anionic antistatic agents with anionic groups such as sulfuric ester salt group, phosphate ester group, and phosphonate group; (c) amino acids, amino sulfuric acid Amphoteric antistatic agents such as esters; (d) nonionic antistatic agents such as amino alcohols, glycerols, and polyethylene glycols; (e) polymers made by quantizing the antistatic agents as mentioned above type antistatic agent, etc. (Patent Document 4). However, regarding the surface protective film described in Patent Document 4, although there is a description of imparting antistatic properties regarding the adhesion of garbage to the adherend, there is no description of a solution that achieves both excellent adhesion performance and anti-pollution performance, and there is still a problem. Technical issues that need further resolution.

In addition, in recent years, a method has been proposed in which the adhesive layer directly contains an antistatic agent instead of containing the antistatic agent in the base film or coating the antistatic agent on the surface of the base film. For example, an antistatic adhesive composition is disclosed, which is characterized in that a salt containing an anion containing a fluoro group and a sulfonyl group is dissolved in a polyether ester plasticizer containing a polyether group in the main chain. Dispersion (Patent Document 5). Regarding the adhesive composition described in Patent Document 5, it is disclosed that a plasticizer composed of a monocarboxylic acid or a dicarboxylic acid having a saturated or unsaturated acyclic hydrocarbon group and a plasticizer composed of the following ester is used as the plasticizer. An ester formed from an alcohol having a non-cyclic hydrocarbon group with 1 to 20 carbon atoms; or an ester formed by epoxidation of an unsaturated group in the unsaturated non-cyclic hydrocarbon group. It is thought that by making the monocarboxylic acid or dicarboxylic acid having a saturated or unsaturated acyclic hydrocarbon group have a number of carbon atoms close to that of the acrylic acid monomer constituting the acrylic acid copolymer used for the adhesive layer. number, the compatibility with the antistatic adhesive composition becomes good, and the plasticizer acrylic antistatic adhesive composition is properly maintained, so bleeding is suppressed. However, although there are disclosed techniques for improving the antistatic performance and bleeding of the adhesive layer formed by cross-linking the antistatic adhesive composition described in Patent Document 5, there is no description of the ability to obtain the peeling speed and bleed-out at low speeds. While achieving excellent adhesive performance with a balanced adhesive force at a high peeling speed, there is still a technical problem of obtaining an adhesive layer with excellent adhesive performance. existing technical documents patent documents

Patent Document 1: Japanese Patent Application Publication No. Sho 63-225677 Patent Document 2: Japanese Patent Application Publication No. 11-256111 Patent document 3: Japanese Patent Application Publication No. 2011-122054 Patent Document 4: Japanese Patent Application Publication No. 11-070629 Patent Document 5: Japanese Patent Application Publication No. 2014-118469

Technical problems to be solved by the present invention

As mentioned above, there is no existing technology that solves the technical problem of simultaneously achieving the following performance requirements for the adhesive layer constituting the surface protective film: (1) achieving a balance of adhesive force at a low peeling speed and a high peeling speed; ( 2) It has anti-pollution properties; (3) It has excellent anti-static properties. In addition, there has been a trade-off between the antistatic performance of an adhesive layer formed using an adhesive composition having antistatic properties and the surface protective film using the adhesive layer, and the anti-pollution performance of the adherend. (trade-off) relationship, it is difficult to improve anti-pollution performance while maintaining antistatic performance. Furthermore, in recent years, as the types of materials of adherends to which surface protective films are bonded have increased, and the surface treatment states of adherends have also varied, the adhesive layer constituting the surface protective film is suitable for all adherends, especially This makes it more difficult to (1) achieve a balance between adhesive force at a low peeling speed and a high peeling speed, and (2) have anti-pollution properties.

The present invention was completed in view of the above situation, and its technical problem is to provide an adhesive composition and an adhesive film and a surface protective film using the adhesive composition. The adhesive composition can be peeled off at a low speed and at a high speed. It has balanced adhesion at peeling speed and achieves both antistatic and anti-contamination properties. Technical means to solve technical problems

As an adhesive composition for use in a surface protective film for polarizing plates, the inventors of the present application have developed an adhesive composition containing an acrylic polymer, an antistatic agent, and a cross-linking agent. The types of compounds copolymerized with the acrylic polymer The research was conducted again, and improvements were made especially to the technical issues of (1) achieving a balance of adhesion between low and high peeling speeds and (2) anti-pollution performance. As a result, it was found that in a (meth)acrylic acid alkyl ester in which the carbon number of the alkyl group (A) is C1 to C10, by combining 2-ethylhexyl acrylate and the glass transition temperature (Tg) of the homopolymer ) is 0°C or above and the content ratio of the monofunctional methacrylate monomer is set to a specific range, which can simultaneously solve the technical problems of (1) and (2) above. Furthermore, by making an adhesive containing an antistatic agent agent composition, thereby completing the present invention.

In order to solve the above technical problems, the present invention provides an adhesive composition, which contains a first acrylic polymer, a cross-linking agent and an ionic compound. It is characterized in that the first acrylic polymer is: a total of 100 weight (A) At least 2 or more kinds of (meth)acrylic acid alkyl esters whose carbon atoms in the alkyl group are C1 to C10, and a total of 1.0 to 6.0 parts by weight of (B) hydroxyl-containing copolymerizable monomers A weight average molecular weight of more than 300,000 and 100 with an acid value of 0.1 to 1.0 copolymerized with at least one or more of (C) carboxyl group-containing copolymerizable monomers, and a total of 0.01 to 0.6 parts by weight An acrylic polymer composed of a copolymer of 10,000 or less, in a total of 100 parts by weight of at least two or more (meth)acrylic acid alkyl esters in which the carbon number of the alkyl group (A) is C1 to C10, One of monofunctional methacrylate monomers containing 2-ethylhexyl acrylate in a proportion of 50 parts by weight or more and a homopolymer with a Tg of 0°C or more in a total proportion of 5 to 40 parts by weight. As described above, the adhesive composition contains a trifunctional or higher isocyanate compound as the crosslinking agent, a crosslinking retardant, and a crosslinking catalyst other than a tin compound as a crosslinking catalyst.

Preferably, the adhesive layer obtained by cross-linking the adhesive composition and the surface protective film formed by laminating a polyester film having a thickness of 15 μm on one side of a polyester film having a thickness of 38 μm are bonded to the surface of the polarizing plate. , when peeling off the surface protective film from the polarizing plate, the adhesion force at a low peeling speed of 0.3m/min is 0.01~0.1N/25mm, and the adhesion force at a high speed peeling speed of 30m/min is 1.0 N/25mm or less.

Preferably, the monofunctional methacrylate monomer whose Tg of the homopolymer is 0° C. or above is selected from the group consisting of n-butyl methacrylate, isobutyl methacrylate, second butyl methacrylate, and methacrylic acid. One or more types of compounds in the group consisting of tert-butyl ester, n-propyl methacrylate, isopropyl methacrylate, ethyl methacrylate, and methyl methacrylate.

Preferably: the adhesive composition further contains a second acrylic polymer, and the second acrylic polymer is a (meth)acrylate monomer in which the carbon number of the alkyl group in (a) is C1 to C18. at least one or more of (b) at least one or more of copolymerizable monomers containing hydroxyl groups, and (c) mono(meth)acrylate monomers containing polyalkylene glycol chains The copolymer formed by copolymerization of at least one or more kinds, relative to a total of 100 parts by weight of at least two or more (meth)acrylic acid alkyl esters whose carbon atoms in the (A) alkyl group are C1 to C10, The adhesive composition contains the second acrylic polymer in a proportion of 0.1 to 5.0 parts by weight.

Preferably: the adhesive composition is an adhesive composition used to form an adhesive layer used in a surface protective film for polarizing plates, and the protective layer of the polarizer of the polarizing plate is selected from TAC-based films and PMMA-based films. , one of the group consisting of PET films, and the surface treatment performed on the surface of the protective layer of the polarizer of the polarizer is selected from untreated, AG treated, LR treated, AR treated, AG-LR treated , one of the groups composed of AG-AR processing.

Preferably: the ionic compound is an ionic compound with a melting point of 25 to 80°C, the cation of the ionic compound is pyridinium, and the adhesive composition is 0.01% relative to 100 parts by weight of the first acrylic polymer. The ionic compound is contained as an essential ingredient in a proportion of ~10 parts by weight.

Preferably, the adhesive layer formed by cross-linking the adhesive composition has a surface resistivity of 1.0×10 ⁺¹² Ω/□ or less, and the adhesive layer is formed using a low refractive index layer containing a fluorine compound. The peeling electrostatic voltage of the low refractive index layer formed from the composition is in the range of +0.3~-0.3kV. After the adhesive layer is attached to the polarizing plate, it is placed in an atmosphere with a temperature of 60°C and a humidity of 90%RH. After being taken out for 2 days, there is no contamination when peeled off after 1 day. The surface base material of the polarizer is one selected from the group consisting of TAC-based films, PMMA-based films, and PET-based films, and in the The surface treatment performed on the surface of the surface substrate is one selected from the group consisting of untreated, AG treated, LR treated, AR treated, AG-LR treated, and AG-AR treated.

Preferably: the (B) hydroxyl-containing copolymerizable monomer is selected from 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, A compound composed of 2-hydroxyethyl (meth)acrylate, N-hydroxy(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, and N-hydroxyethyl(meth)acrylamide At least one or more of the groups, The (C) carboxyl-containing copolymerizable monomer is selected from (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, 2-(meth)acryloxy Ethyl hexahydrophthalate, 2-(meth)acryloxypropyl hexahydrophthalate, 2-(meth)acryloxyethyl phthalate Ester, 2-(meth)acryloxyethyl succinate, 2-(meth)acryloxyethyl maleate, carboxypolycaprolactone mono(meth)acrylate, 2- At least one of the compound group consisting of (meth)acryloxyethyl tetrahydrophthalate.

Preferably: the cross-linking retardant is a compound of keto-enol tautomer, and the cross-linking retardant is contained in a ratio of 0.1 to 300 parts by weight relative to 100 parts by weight of the first acrylic polymer. , the crosslinking catalyst is at least one metal chelate compound selected from the group consisting of aluminum chelate compounds, titanium chelate compounds, and iron chelate compounds, relative to 100 parts by weight of the first acrylic compound The polymer contains the cross-linking catalyst in a proportion of 0.001 to 0.5 parts by weight, and the weight ratio of the cross-linking retardant/cross-linking catalyst is 80 to 1000.

Preferably: the adhesive composition contains a modified polyether with an HLB value of 6 to 12 and a weight average molecular weight of less than 10,000 in a proportion of 0.01 to 0.5 parts by weight relative to 100 parts by weight of the first acrylic polymer. Siloxane compounds.

Preferably: the second acrylic polymer is composed of at least one (meth)acrylate monomer with a carbon number of C1 to C18 in the alkyl group of (a) for a total of 100 parts by weight, and a total of 2.0 ~12.0 parts by weight of at least one or more of (b) hydroxyl-containing copolymerizable monomers and a total of 1~30 parts by weight of (c) polyolefin-based glycol chain-containing mono(meth)acrylate monomer At least one copolymer of at least one copolymer with a weight average molecular weight of more than 300,000 and less than 800,000, in the (B) hydroxyl-containing copolymerizable monomer contained in the first acrylic polymer The value (B-1) of at least one or more kinds of the total weight parts of the first acrylic polymer with respect to the total of 100 weight parts of the second acrylic polymer contains the (b) Ratio (b-1)/(B-) of the total weight parts of at least one or more hydroxyl copolymerizable monomers relative to the total 100 weight parts of the second acrylic polymer (b-1) 1) In the range of 1.0~2.0.

Preferably: for the polyolefin-based glycol chain-containing mono(meth)acrylate monomer, the average number of repeating units of the alkylene oxide constituting the polyolefin-based glycol chain is 3 to 14, so The diester component in the polyolefin-based glycol chain-containing mono(meth)acrylate monomer is less than 0.2%, and in 100 parts by weight of the second acrylic polymer, 1 to 50 parts by weight The proportion contains a group selected from the group consisting of polyolefin glycol mono(meth)acrylate, methoxy polyolefin glycol (meth)acrylate, and ethoxy polyolefin glycol (meth)acrylate. At least one or more of the group is used as the polyalkenyl glycol chain-containing mono(meth)acrylate monomer.

Furthermore, the present invention provides an adhesive film characterized in that an adhesive layer obtained by cross-linking the adhesive composition is laminated on one side of a resin film.

Furthermore, the present invention provides a surface protective film using the above-mentioned adhesive film.

Furthermore, the present invention provides a surface protective film for polarizing plates using the above-mentioned adhesive film.

Furthermore, the present invention provides an optical film with an adhesive layer in which an adhesive layer obtained by crosslinking the adhesive composition is laminated on at least one surface of the optical film.

Furthermore, the present invention provides an adhesive film in which an antistatic treatment and an antifouling treatment are performed on one side of the resin film opposite to the side on which the adhesive layer is formed. Invention effect

In the adhesive composition of the present invention, in a total of 100 parts by weight of at least two or more (meth)acrylic acid alkyl esters whose carbon atoms in the (A) alkyl group are C1 to C10, the first acrylic polymer The product contains 2-ethylhexyl acrylate in a proportion of 50 parts by weight or more, and 1 of the monofunctional methacrylate monomers whose Tg of the homopolymer is 0°C or more in a total proportion of 5 to 40 parts by weight. More than one species. This makes it possible to achieve both (1) a balance of adhesion between a low peeling speed and a high peeling speed and (2) contamination resistance even in a surface protective film for polarizing plates using PMMA as a base material. performance. In addition, the adhesive composition of the present invention contains one or more monofunctional methacrylate monomers whose homopolymer Tg is 0°C or higher, which helps to achieve both (1) low peeling speed and The reasons for achieving a balance of adhesive force at high peeling speed and (2) anti-pollution properties are not yet clear. As a possible reason, it is speculated that although these methacrylate monomers do not have polar functional groups such as carboxyl groups or amide groups, or long-chain alkyl groups exceeding C10, they can obtain polymers with high Tg. The adhesive properties in the cross-linked state are greatly improved. In addition, the affinity with methyl methacrylate, which is the main component of PMMA-based films, is also considered to be one of the reasons.

Detailed implementation

Hereinafter, the present invention will be described based on suitable embodiments. The adhesive composition of this embodiment contains an acrylic polymer, a cross-linking agent, and an ionic compound, and is characterized in that the acrylic polymer is: A total of 100 parts by weight of at least two or more alkyl (meth)acrylates in which the carbon number of the alkyl group (A) is C1 to C10, A total of 1.0 to 6.0 parts by weight of at least one or more of (B) hydroxyl-containing copolymerizable monomers, and Composed of a copolymer with an acid value of 0.1 to 1.0 and a weight average molecular weight of more than 300,000 and less than 1 million, copolymerized by at least one or more copolymerizable monomers containing carboxyl groups (C) in a total of 0.01 to 0.6 parts by weight of acrylic polymers, The (A) alkyl group contains at least two kinds of (meth)acrylic acid alkyl esters with carbon atoms of C1 to C10 in a total of 100 parts by weight, containing 2-ethyl acrylate in a proportion of more than 50 parts by weight. Hexyl ester, containing one or more monofunctional methacrylate monomers whose Tg of the homopolymer is 0°C or higher in a total proportion of 5 to 40 parts by weight, The adhesive composition contains a trifunctional or higher isocyanate compound as the crosslinking agent, a crosslinking retardant, and a crosslinking catalyst other than a tin compound as a crosslinking catalyst.

The acrylic polymer used in the adhesive composition of this embodiment is a main component polymer of the adhesive composition, and may be called a first acrylic polymer when distinguished from a second acrylic polymer described below. The first acrylic polymer is an acrylic polymer having a glass transition temperature (Tg) of 0° C. or lower. Moreover, it is preferable that the 1st acrylic polymer is a copolymer containing (A) the alkyl (meth)acrylate whose carbon number of the alkyl group is C1-C10 as a main component.

Examples of (A) alkyl (meth)acrylate in which the carbon number of the alkyl group is C1 to C10 include methyl (meth)acrylate, ethyl (meth)acrylate, and n-propyl (meth)acrylate. Ester, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, second butyl (meth)acrylate, third butyl (meth)acrylate, ( Amyl methacrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate Ester, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, etc. The alkyl group of these (meth)acrylic acid alkyl esters may be either acyclic (linear, branched) or cyclic (monocyclic, polycyclic).

Preferably, the first acrylic polymer contains 2-ethylhexyl acrylate in a proportion of 50 parts by weight or more and 5 to 40 parts by weight in total of 100 parts by weight of (A). The polymer has one or more monofunctional methacrylate monomers having a Tg of 0° C. or higher. Furthermore, it is preferable that 2-ethylhexyl acrylate is contained in a proportion of 50 parts by weight or more, more preferably 60 parts by weight or more, particularly preferably 70 parts by weight or more, in the total 100 parts by weight of (A). ester. In addition, among the (meth)acrylic acid alkyl esters in which the carbon number of the alkyl group (A) is C1 to C10, examples of the monofunctional methacrylate monomer having a Tg of 0° C. or higher include those selected from the group consisting of: n-butyl acrylate, isobutyl methacrylate, 2nd butyl methacrylate, 3rd butyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, ethyl methacrylate, methacrylate Methyl acrylate, n-amyl methacrylate, isopentyl methacrylate, n-hexyl methacrylate, isohexyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, bicyclomethacrylate One or more types of compounds in the group consisting of amyl esters. Among these monofunctional methacrylate monomers with a Tg of 0° C. or higher, those in which the carbon number of the alkyl group is C1 to C6 are preferred, and those in which the carbon number of the alkyl group is C1 to C4 are more preferred. The methacrylate monomer is particularly preferably selected from the group consisting of n-butyl methacrylate, isobutyl methacrylate, second butyl methacrylate, third butyl methacrylate, n-propyl methacrylate, methyl One or more types from the group consisting of isopropyl acrylate, ethyl methacrylate, and methyl methacrylate. In addition, in the total 100 parts by weight of (A), the proportion is preferably 5 to 40 parts by weight in total, more preferably 8 to 40 parts by weight in total, and particularly preferably 10 to 35 parts by weight in total. The ratio contains one or more types of monofunctional methacrylate monomers with a Tg of 0°C or higher. In addition, in the following description, when a monomer is simply called Tg, it means the Tg of a homopolymer.

As the (B) hydroxyl-containing copolymerizable monomer used in the first acrylic polymer, it is preferably selected from the group consisting of 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, (meth)acrylate, base) 4-hydroxybutyl acrylate, 2-hydroxyethyl (meth)acrylate, N-hydroxy(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-hydroxyethyl( At least one of the compound group consisting of meth)acrylamide and the like. The first acrylic polymer is preferably in a proportion of 1.0 to 6.0 parts by weight in total, more preferably in a proportion of 2.0 to 6.0 parts by weight in total, and particularly preferably in a proportion of 100 parts by weight in total of (A). At least one type of (B) hydroxyl-containing copolymerizable monomer is contained in a proportion of 2.5 to 5.5 parts by weight.

As the (C) carboxyl group-containing copolymerizable monomer used in the first acrylic polymer, it is preferably selected from the group consisting of (meth)acrylic acid, carboxyethyl (meth)acrylate, and carboxypentyl (meth)acrylic acid. Ester, 2-(meth)acryloxyethyl hexahydrophthalate, 2-(meth)acryloxypropylhexahydrophthalate, 2-(methyl) Acryloxyethyl phthalate, 2-(meth)acryloxyethyl succinate, 2-(meth)acryloxyethyl maleate, carboxypolycaprolactone At least one of the compound group consisting of ester mono(meth)acrylate, 2-(meth)acryloyloxyethyl tetrahydrophthalate, and the like. The first acrylic polymer is preferably in a proportion of 0.01 to 0.6 parts by weight in total, more preferably in a proportion of 0.01 to 0.5 parts by weight in total, and particularly preferably in a proportion of 100 parts by weight in total of (A). (C) At least one type of carboxyl group-containing copolymerizable monomer is contained in a proportion of 0.01 to 0.4 parts by weight.

The preparation method of the first acrylic polymer is not particularly limited, and suitable and well-known polymerization methods such as solution polymerization and emulsion polymerization can be used. It is preferable that the weight average molecular weight of the first acrylic polymer exceeds 300,000 and is 1,000,000 or less. In addition, the acid value of the first acrylic polymer is preferably 0.1 to 1.0. As a result, the anti-pollution performance can be improved. Here, the "acid value" is one of the indicators showing the acid content, and is expressed as the number of mg of potassium hydroxide required to neutralize 1 g of a carboxyl group-containing polymer.

The adhesive composition of this embodiment contains (G) an antistatic agent. The (G) antistatic agent in this embodiment is preferably an ionic compound with a melting point of 25 to 80°C. Preferably, the ionic compound is solid at normal temperature. Normal temperature is, for example, a temperature lower than 25°C. Specifically, an ionic compound that is solid at 23°C is preferred. It is preferable that the adhesive composition of this embodiment contains the ionic compound as an essential component in a ratio of 0.01 to 10 parts by weight relative to 100 parts by weight of the first acrylic polymer.

Examples of the anion of the ionic compound include hexafluorophosphate (PF ₆ ^- ), thiocyanate (SCN ^- ), perchlorate (ClO ₄ ^- ), tetrafluoroborate (BF ₄ ^- ), and the like. Inorganic anions; carboxylates (RCOO ^- ), sulfonates (RSO ₃ ^- ), alcoholate salts or phenoloxide salts (RO ^- ), organoimide salts (R ₂ N ^- ), methide salts ( Organic anions such as R ₃ C ^- ), organic borate (R ₄ B ^- ), etc. R contained in each general formula of the organic anion is an organic group that may have fluorine substitution. Examples of the organic group include at least one of an alkyl group, an alkoxy group, an aromatic group (aryl group, aralkyl group, etc.), an aliphatic or aromatic carbonyl group, an aliphatic or aromatic sulfonyl group, etc. More than one species. In the organic group contained in the anion, part or all of the hydrogen atoms may be substituted with one or more halogen atoms such as fluorine atom.

Examples of the cation of the ionic compound include pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiouronium, piperonium One of the group consisting of pyridinium, pyrazolium, methyl carbocation (methylium), and morpholinium. Preferably the cation of the ionic compound is pyridinium. In the organic group contained in the cation, part or all of the hydrogen atoms may be substituted with one or more halogen atoms such as fluorine atom. When the anion and/or cation of the ionic compound contains an organic group such as an alkyl group, an ionic compound with a melting point of 25 to 80°C can be obtained by selecting the chain length of the alkyl group or the position and number of substituents.

Specific examples of the ionic compound include 1-octylpyridinium hexafluorophosphate, 1-nonylpyridinium hexafluorophosphate, and 2-methyl-1-dodecylpyridinium hexafluorophosphate. Phosphate, 3-methyl-1-dodecylpyridinium hexafluorophosphate, 1-octylpyridinium dodecylbenzene sulfonate, 1-dodecylpyridinium thiocyanate, 1 -Dodecylpyridinium dodecylbenzenesulfonate, 4-methyl-1-octylpyridinium hexafluorophosphate, 1-nonylpyridinium 2-iodobenzenesulfonate, 4,5- Diiodo-1-butyl-3-methylimidazolium hexafluorophosphate, 2-methyl-1-dodecylpyridinium 2-iodobenzenesulfonate, 4,5-diiodo-1-butanium 1-3-Methylimidazolium 3-iodobenzenesulfonate, 1-octyl-2-methylpyridinium trifluoromethanesulfonate, 1,2,3-trimethylimidazolium pentafluoroethanesulfonate acid salt, 1-butyl-2,3-dimethylimidazolium trifluoromethanesulfonate, 1-hexyl-4-methylpyridinium pentafluoroethanesulfonate, 1-octyl-3-methyl Pyridinium trifluoromethanesulfonate, n-octylpyridinium trifluoromethanesulfonate, 1-propyl-3-methylpyridinium nonafluoromethanesulfonate, 3-methyl-1-octyl Pyridinium nonafluorobutane sulfonate, methyltrioctylammonium tris(pentafluorobenzenesulfonyl)methide salt, 1-ethyl-3-methylimidazolium tetrakis(pentafluorophenyl)borate , 1-butyl-1-methylpiperidinium bis(pentafluorobenzenesulfonyl)imide salt, etc.

The adhesive composition of this embodiment further contains a trifunctional or higher-functional isocyanate compound as (D) a cross-linking agent. Examples of the trifunctional or higher isocyanate compound include abbreviations of diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, and xylylene diisocyanate. Modified diurea or modified isocyanurate, adducts with trimethylol or higher polyhydric alcohols such as trimethylolpropane or glycerin, etc. The proportion of the trifunctional or higher isocyanate compound that is the crosslinking agent (D) is, for example, preferably 0.1 to 10 parts by weight, more preferably 0.1 to 10 parts by weight relative to 100 parts by weight of the first acrylic polymer. The cross-linking agent (D) is contained in a proportion of 6 parts by weight.

The adhesive composition of this embodiment may further contain (E) a crosslinking retardant. Examples of (E) the crosslinking retardant include methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, and acetoacetic acid. β-keto esters such as octadecyl ester, or β-diketones such as acetyl acetone, 2,4-hexanedione, and benzoyl acetone. These cross-linking retardants are compounds of keto-enol tautomers. In an adhesive composition using a polyisocyanate compound as a cross-linking agent, the isocyanate group of the (D) cross-linking agent is blocked. (block) can suppress excessive viscosity increase and gelation of the adhesive composition after blending the cross-linking agent, and can extend the storage period of the adhesive composition. (E) The crosslinking retarder is particularly preferably at least one selected from the group consisting of acetoacetone and ethyl acetoacetate. The (E) crosslinking retardant is preferably contained in a proportion of 0.1 to 300 parts by weight relative to 100 parts by weight of the first acrylic polymer.

The adhesive composition of this embodiment may contain a crosslinking catalyst other than a tin compound as (F) a crosslinking catalyst. When a polyisocyanate compound is used as a cross-linking agent, the (F) cross-linking catalyst may be a substance that functions as a catalyst for the reaction (cross-linking reaction) between the acrylic polymer and the cross-linking agent. As (F) the crosslinking catalyst, a metal chelate compound is preferred. A metal chelate compound is a compound in which one or more polydentate ligands L are bonded to a 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. Specific examples of the metal chelate compound include tris(2,4-pentane-dionato)iron III, triacetyl iron acetonate, and triacetyl iron. Titanium acetonate, ruthenium triacetyl acetonate, zinc diacetyl acetonate, aluminum triacetyl acetonate, zirconium tetraacetyl acetonate, tris(2,4-hexanedione)iron(III), bis(2,4-hexanedione) ketone) zinc, tris(2,4-hexanedione)titanium, tris(2,4-hexanedione)aluminum, tetrakis(2,4-hexanedione)zirconium, etc.

(F) The crosslinking catalyst is preferably at least one metal chelate compound selected from the group consisting of aluminum chelate compounds, titanium chelate compounds, and iron chelate compounds. The (F) crosslinking catalyst is preferably contained in a proportion of 0.001 to 0.5 parts by weight relative to 100 parts by weight of the first acrylic polymer.

The (E) cross-linking retardant has an effect of inhibiting cross-linking, contrary to the (F) cross-linking catalyst. Therefore, it is preferable to appropriately set the ratio of the (E) cross-linking retardant to the (F) cross-linking catalyst. In order to extend the storage period of the adhesive composition and improve the storage stability, the weight part ratio of (E)/(F) is preferably 80 to 1000, more preferably 80 to 700, and particularly preferably 80 to 300. Here, the weight part ratio of (E)/(F) is the value of the quotient obtained by dividing the weight part of (E) by the weight part of (F).

The adhesive composition of this embodiment may further contain (H) a polyether-modified siloxane compound as an optional component. (H) The polyether-modified siloxane compound is a siloxane compound with a polyether group. In addition to the usual siloxane unit [-SiR ¹ ₂ -O-], it also has a siloxane compound with a polyether group. Alkane unit [-SiR ¹ (R ² O(R ³ O) _n R ⁴ )-O-]. Here, R ¹ represents one or more alkyl groups or aryl groups, R ² and R ³ represent one or more alkylene groups, R ⁴ represents one or more alkyl groups or acyl groups, etc. ( terminal group). Examples of the polyether group include polyoxyalkylene groups such as polyoxyalkylene groups [(C ₂ H ₄ O) _n ] and polyoxypropylene groups [(C ₃ H ₆ O) _n ]. In the siloxane unit having a polyether group, the end of the polyether group may be an OH group (R ⁴ =H in the above general formula (1)).

(H) The polyether-modified siloxane compound is preferably a polyether-modified siloxane compound with an HLB value of 6 to 12. In addition, it is preferably contained in a proportion of 0.01 to 0.5 parts by weight, more preferably in a proportion of 0.02 to 0.35 parts by weight, and particularly preferably in a proportion of 0.02 to 0.25 parts by weight relative to 100 parts by weight of the first acrylic polymer. H) Polyether modified siloxane compound. The HLB value refers to the hydrophilic-lipophilic balance value (lipophilic to hydrophilic ratio) specified in, for example, JIS K3211 (surfactant terminology). The polyether-modified siloxane compound can be obtained, for example, by grafting an organic compound having an unsaturated bond and a polyoxyalkylene group onto the main chain of a polyorganosiloxane having a hydrogenated siloxane group using a hydrosilylation reaction. . Specific examples include dimethylsiloxane-methyl(polyoxyethylene)siloxane copolymer, dimethylsiloxane-methyl(polyoxyethylene)siloxane-methyl( Polyoxypropylene)siloxane copolymer, dimethylsiloxane-methyl (polyoxypropylene)siloxane polymer, etc.

By blending the (H) polyether modified siloxane compound into the adhesive composition, the adhesion and reoperability of the adhesive layer can be improved. (H) The weight average molecular weight of the polyether-modified siloxane compound is preferably 10,000 or less. From the perspective of compatibility with acrylic polymers, although the compatibility is better when the HLB value is low and the molecular weight is low, when it is a polyether-modified siloxane compound with a low molecular weight, even if the HLB value is high and Even with slightly lower compatibility with polymers, excellent antistatic properties can be obtained.

The adhesive composition of this embodiment may contain a second acrylic polymer as an optional component. By further containing a second acrylic polymer obtained by copolymerizing a polyolefin-based glycol chain-containing mono(meth)acrylate monomer in the adhesive composition, the compatibility between the ionic compound and the acrylic polymer can be improved. properties, further improving antistatic properties and anti-pollution properties. Examples of the second acrylic polymer include (a) at least one (meth)acrylate monomer having an alkyl group having a carbon number of C1 to C18, and (b) a copolymerizable monomer containing a hydroxyl group. A copolymer obtained by copolymerizing at least one or more of (c) mono(meth)acrylate monomers containing polyolefinic glycol chains.

Examples of the (meth)acrylate monomer in which the (a) alkyl group used in the second acrylic polymer has C1 to C18 carbon atoms include methyl (meth)acrylate and (methyl)acrylate. Ethyl acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, second-butyl (meth)acrylate, Tert-butyl (meth)acrylate, amyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate , 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, ( Lauryl methacrylate, tridecyl (meth)acrylate, myristyl (meth)acrylate, pentadecyl (meth)acrylate, cetyl (meth)acrylate Alkyl ester, heptadecyl (meth)acrylate, stearyl (meth)acrylate, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, etc. The alkyl group of (a) may be either acyclic (linear, branched) or cyclic (monocyclic, polycyclic). The (meth)acrylate monomer with the carbon number of the alkyl group (a) used in the second acrylic polymer being C1 to C18 can also be selected from the (A) used in the first acrylic polymer. ) The same compound or ratio as the alkyl (meth)acrylate whose alkyl group has carbon atoms of C1 to C10. Or (a) may contain a compound different from (A). Furthermore, even if the monomers are the same compound, the ratio in (a) may be different from the ratio in (A). For example, the second acrylic polymer may be a copolymer in which alkyl methacrylate is not copolymerized. In addition, the second acrylic polymer may also be a copolymer of a (meth)acrylate monomer with a carbon number of C11 to C18 that is not copolymerized with an alkyl group, or the second acrylic polymer may be A (meth)acrylate monomer containing an alkyl group with carbon atoms ranging from C11 to C18.

As the (b) hydroxyl-containing copolymerizable monomer used in the second acrylic polymer, it is preferably selected from the group consisting of 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, (meth)acrylate, base) 4-hydroxybutyl acrylate, 2-hydroxyethyl (meth)acrylate, N-hydroxy(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-hydroxyethyl( At least one of the compound group consisting of meth)acrylamide and the like. Preferably: the second acrylic polymer has a total of 100 parts by weight relative to a total of 100 parts by weight of at least one (meth)acrylate monomer with a carbon number of C1 to C18 in the alkyl group. It is a ratio of 2.0 to 12.0 parts by weight, more preferably a ratio of 3.0 to 12.0 parts by weight in total, particularly preferably a ratio of 4.0 to 12.0 parts by weight in total (b) at least one of the hydroxyl-containing copolymerizable monomers. above. The (b) hydroxyl-containing copolymerizable monomer used for the second acrylic polymer may also be selected from the same compound as the (B) hydroxyl-containing copolymerizable monomer used for the first acrylic polymer. Proportion. Or (b) may contain a compound different from (B). Furthermore, even if the monomers are the same compound, the ratio in (b) may be different from the ratio in (B).

The second acrylic polymer used in the adhesive composition of this embodiment contains (c) a polyolefin-based glycol chain-containing mono(meth)acrylate monomer. In the adhesive composition of this embodiment, the second acrylic polymer containing the (c) polyolefin-based glycol chain-containing mono(meth)acrylate monomer functions as an antistatic auxiliary agent. In addition, the first acrylic polymer may be a copolymer of a mono(meth)acrylate monomer that has not been copolymerized with a polyolefin glycol chain, or may be the same as the second acrylic polymer. Copolymerization of mono(meth)acrylate monomers containing polyolefin-based glycol chains. Preferably, it is 0.1 to 5.0, based on 100 parts by weight in total of at least two or more alkyl (meth)acrylates with carbon atoms of C1 to C10 in the (A) alkyl group used in the first acrylic polymer. The second acrylic polymer is contained in a proportion of parts by weight, more preferably in a proportion of 0.1 to 3.5 parts by weight, and particularly preferably in a proportion of 0.1 to 2.5 parts by weight.

(c) The polyolefin glycol chain-containing mono(meth)acrylate monomer is any one of the plurality of hydroxyl groups that the polyolefin glycol has and is esterified as a (meth)acrylate. compounds. Since the (meth)acrylate group is a polymerizable group, it can be copolymerized with the second acrylic polymer. It may be a polyalkenyl glycol mono(meth)acrylate in which other hydroxyl groups are still OH, or an alkoxy polyalkenyl glycol mono(meth)acrylate in which other hydroxyl groups are converted into alkyl ethers, etc. In addition, polyolefin glycol mono(meth)acrylate corresponds to (c), so even if it contains a hydroxyl group, it is not classified into (B) or (b).

The polyolefin glycol constituting the polyolefin glycol chain may be a glycol compound having one or more alkylene groups. Examples thereof include polyethylene glycol, polypropylene glycol, and polybutylene glycol. , polyethylene glycol-polypropylene glycol, polyethylene glycol-polybutylene glycol, polypropylene glycol-polybutylene glycol, polyethylene glycol-polypropylene glycol-polybutylene glycol, etc.

Regarding the (c) polyalkenyl glycol chain-containing mono(meth)acrylate monomer, it is preferable that the average number of repeating units of the alkylene oxide groups constituting the polyalkenyl glycol chain is 3 to 14. "The average number of repeating units of the alkylene oxide group" refers to the portion of the "polyolefin glycol chain" contained in the molecular structure of the mono(meth)acrylate monomer containing the polyolefin glycol chain in (c) , the average number of repeats of alkylene oxide units. Furthermore, the diester component in (c) the polyolefin-based glycol chain-containing mono(meth)acrylate monomer is preferably 0.2% or less. "The diester component in the monomer" refers to the polyolefin glycol di(meth)acrylate contained in (c) the polyolefin glycol chain-containing mono(meth)acrylate monomer. Rate (% by weight).

(c) The polyolefin glycol chain-containing mono(meth)acrylate monomer is preferably selected from the group consisting of polyolefin glycol mono(meth)acrylate and methoxypolyolefin glycol (methyl) At least one of the group consisting of acrylate and ethoxy polyalkenyl glycol (meth)acrylate. The second acrylic polymer is preferably composed of 1 to 100 parts by weight of at least one or more (meth)acrylate monomers in which the carbon number of the alkyl group of (a) is C1 to C18. The polyolefin-based glycol chain-containing mono(meth)acrylate monomer (c) is contained in a proportion of 30 parts by weight, more preferably in a proportion of 2 to 30 parts by weight, and particularly preferably in a proportion of 5 to 25 parts by weight.

The preparation method of the second acrylic polymer is not particularly limited, and suitable and well-known polymerization methods such as solution polymerization and emulsion polymerization can be used. The second acrylic polymer is preferably a copolymer having a weight average molecular weight of more than 300,000 and not more than 800,000. The weight average molecular weight of the second acrylic polymer may be the same as the weight average molecular weight of the first acrylic polymer, or may be greater than or less than the weight average molecular weight of the first acrylic polymer. The second acrylic polymer may have functionality reactive with the (D) cross-linking agent. The second acrylic polymer may be a copolymer in which a carboxyl group-containing copolymerizable monomer is not copolymerized, or the same carboxyl group-containing copolymerizable monomer as the first acrylic polymer may be copolymerized. (D) The cross-linking agent may also participate in the cross-linking of the first acrylic polymer and the second acrylic polymer.

The total weight part of at least one or more kinds of (B) hydroxyl-containing copolymerizable monomers contained in the first acrylic polymer relative to a total of 100 weight parts of the first acrylic polymer (B-1 ) and the total weight parts of at least one or more of (b) hydroxyl-containing copolymerizable monomers contained in the second acrylic polymer relative to a total of 100 parts by weight of the second acrylic polymer ( The ratio (b-1)/(B-1) of b-1) is preferably in the range of 1.0 to 2.0.

The adhesive composition of this embodiment is not limited to the above-mentioned additives, and may also be appropriately blended with surfactants, curing accelerators, plasticizers, fillers, curing retardants, processing aids, anti-aging agents, antioxidants, etc. Well-known additives. These additives can be used individually or in combination of 2 or more types.

The adhesive composition of this embodiment is suitable as an adhesive composition for forming an adhesive layer used in a surface protective film for polarizing plates. The adhesive layer of the surface protective film can also be bonded to the protective layer of the polarizer of the polarizer. Here, the protective layer of the polarizer of the polarizing plate may be at least one selected from the group consisting of TAC-based films, PMMA-based films, and PET-based films. Here, TAC is the abbreviation of cellulose triacetate, PMMA is the abbreviation of polymethylmethacrylate, and PET is the abbreviation of polyethylene terephthalate. In addition, the surface treatment performed on the surface of the protective layer of the polarizer of the polarizer may be selected from the group consisting of untreated, AG treated, LR treated, AR treated, AG-LR treated, and AG-AR treated. At least one or more. Here, AG refers to anti-glare (Anti Glare), LR refers to low reflection (Low Reflection), and AR refers to anti-reflection (Anti Reflection).

The adhesive layer formed by cross-linking the adhesive composition of this embodiment preferably has a surface resistivity of 1.0×10 ⁺¹² Ω/□ or less, more preferably 5.0×10 ⁺¹¹ Ω/□ or less. , particularly preferably 1.0×10 ⁺¹¹ Ω/□ or less. If the surface resistivity is high, the performance of releasing static electricity generated when peeling off the adhesive layer from the adherend is poor. Therefore, by making the surface resistivity sufficiently small, it is possible to reduce the peeling electrostatic voltage caused by the static electricity generated when peeling off the adhesive layer from the adherend, thereby suppressing the influence on the adherend.

The adhesive layer formed by cross-linking the adhesive composition of the present embodiment has a preferable peeling electrostatic voltage for a low refractive index layer formed using a fluoride-containing low refractive index layer forming composition. Within the range of +0.3~-0.3kV. Examples of the fluoride used in the composition for forming a low refractive index layer include one or more of fluorinated olefins, fluorinated vinyl ethers, fluorinated alkyl (meth)acrylates, and the like. Condensates of polymers such as fluorinated copolymers and silane compounds containing fluorinated alkyl groups. In addition to fluorinated monomers, unfluorinated monomers such as olefins, vinyl ethers, and (meth)acrylates may also be copolymerized in the fluorinated copolymer. The low refractive index layer may be combined with a high refractive index layer or the like to form an antireflection layer.

When measuring the peeling electrostatic voltage of the low refractive index layer, examples of base materials used to form the low refractive index layer on the surface include PMMA base materials and TAC base materials. In addition, the peeling electrostatic voltage of the adhesive layer formed by cross-linking the adhesive composition of this embodiment to the plane layer without any treatment on the surface of the PMMA base material and the TAC base material is preferably +0.3 to -0.3 kV. within the range.

It is preferable to laminate the adhesive layer to an adherend such as a polarizing plate, place it in an atmosphere with a temperature of 60°C and a humidity of 90% RH for 2 days (48 hours), take it out from the atmosphere, and peel it off after 1 day. It is non-polluting. Examples of the adherend include a polarizing plate in which a protective layer is laminated on a polarizer and the surface of the protective layer is subjected to low-reflection surface treatment with a fluoride-containing composition. The fluoride-containing composition used for the low-reflection surface treatment may be the same as or different from the above-mentioned resin composition for forming the fluoride-containing low refractive index layer. Examples of the protective layer and surface treatment include the protective layer of the above-mentioned polarizer and the surface treatment performed on its surface.

A surface protective film in which an adhesive layer cross-linked with the adhesive composition of this embodiment and a thickness of 15 μm was laminated on one side of a polyester film with a thickness of 38 μm was bonded to the surface of the polarizing plate. Finally, when peeling off the surface protective film from the polarizing plate, the adhesion force at a low peeling speed of 0.3m/min is 0.01~0.1N/25mm, and the adhesion force at a high speed peeling speed of 30m/min is preferably It is 1.0N/25mm or less, and the adhesive force at a high-speed peeling speed of 30m/min is more preferably 0.2~1.0N/25mm. As a result, the change in adhesive force due to the peeling speed is small, and rapid peeling is possible even in the case of high-speed peeling. In addition, even when the surface protective film is temporarily peeled off for re-adhering, it does not require excessive force and can be easily peeled off from the adherend.

The gel fraction of the adhesive layer obtained by crosslinking the adhesive composition of this embodiment is preferably 95 to 100%, and more preferably 97 to 100%. In this way, by making the gel fraction of the adhesive layer high, the adhesive force will not become too large at a low peeling speed, and the dissolution of unpolymerized monomers or oligomers from the copolymer can be reduced, thereby improving re-use. Operability and durability under high temperature and high humidity, and inhibits contamination of adherends.

The adhesive film of this embodiment is formed by forming an adhesive layer obtained by crosslinking the adhesive composition of this embodiment on one or both sides of a resin film. Moreover, the surface protective film of this embodiment is a surface protective film in which the adhesive layer which crosslinked the adhesive composition of this embodiment was formed on one side of a resin film. The adhesive composition of this embodiment has excellent antistatic properties, has an excellent balance of adhesive force at low peeling speeds and high peeling speeds, and further has anti-pollution properties. Therefore, it can be suitably used as a surface protective film of a polarizing plate.

As the base film of the adhesive layer or the release film (separation film) that protects the adhesive surface, a resin film such as a polyester film can be used. Antistatic treatment and antifouling treatment may be performed on one side of the resin film opposite to the side on which the adhesive layer is formed. Examples of the antistatic treatment include application of an antistatic agent, kneading, and the like. Examples of antifouling treatments include treatments using silicone-based, fluorine-based release agents or coating agents, silicon dioxide particles, and the like. You can also use polysilicone-based, fluorine-based, long-chain alkyl-based release agents, etc. to perform release treatment on the surface of the release film that is in contact with the adhesive surface of the adhesive layer.

Furthermore, by laminating an adhesive layer obtained by crosslinking the adhesive composition of the present embodiment on at least one surface of the optical film, an optical film with an adhesive layer can be obtained. Examples of optical films include polarizing films, retardation films, anti-reflection films, anti-glare films, ultraviolet absorption films, infrared absorption films, optical compensation films, brightness improvement films, and the like. Examples of equipment to which optical members are applied include liquid crystal panels, organic EL panels, touch panels, and the like.

In the case of an optical surface protective film and an adhesive film such as a surface protective film for polarizing plates, it is preferable that the base film and the adhesive layer have sufficient transparency. Example

Hereinafter, the present invention will be specifically described through examples. <Preparation of the first acrylic polymer> [Example 1] Nitrogen gas was introduced into the reaction device equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas introduction pipe, and the air in the reaction device was replaced with nitrogen gas. Then, 70 parts by weight of 2-ethylhexyl acrylate, 30 parts by weight of n-butyl methacrylate, 5.5 parts by weight of 8-hydroxyoctyl acrylate, 0.2 parts by weight of acrylic acid and solvent ( ethyl acetate). Then, 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was added dropwise over 2 hours, and the reaction was carried out at 65° C. for 6 hours, thereby obtaining the first acrylic polymer used in Example 1. [Examples 2 to 6 and Comparative Examples 1 to 4] Except that the compositions of the monomers were adjusted to those described in (A), (B), and (C) of Table 1, the same method as the above-mentioned first acrylic polymer solution used in Example 1 was used to obtain The first acrylic polymer solution in Examples 2 to 6 and Comparative Examples 1 to 4. In addition, the first acrylic polymer used in Examples 1 to 6 and Comparative Examples 1 to 4 is a copolymer with a weight average molecular weight of more than 300,000 and 1,000,000 or less.

＜Preparation of adhesive composition and surface protective film＞ [Example 1] To the first acrylic polymer solution of Example 1 prepared in the above manner, 2.0 parts by weight of the cross-linking agent (CORONATE HX), 9 parts by weight of acetyl acetone, and 0.1 parts by weight of the cross-linking catalyst (titanium triacetyl acetone) were added. , 0.9 parts by weight of antistatic agent (3-methyl-1-octylpyridinium nonafluorobutane sulfonate), 0.05 parts by weight of polyether modified siloxane compound (HLB=7), 2-ethyl acrylic acid A copolymer with a weight average molecular weight (Mw) of 600,000, which is copolymerized with hydroxyhexyl ester, 8-hydroxyoctyl acrylate, and methoxypolyethylene glycol acrylate (n=8) in a weight ratio of 100:8:15. 0.2 parts by weight, stir and mix to obtain the adhesive composition of Example 1. After the adhesive composition was coated on a release film (PET film coated with polysiloxane resin), the solvent was removed by drying at 90° C. to obtain an adhesive layer with a thickness of 20 μm. Then, the adhesive layer attached to the release film is transferred to the surface of the base film (PET film with antistatic and antifouling treatment on one side) opposite to the antistatic and antifouling surface. , the surface protection film of Example 1 having a laminated structure of "base film/adhesive layer/release film" was obtained. [Examples 2 to 6 and Comparative Examples 1 to 4] Except that the compositions of the additives were adjusted to those described in (D) to (H) and (J) of Tables 1 to 2, Examples 2 to 6 and Examples 2 to 6 were obtained in the same manner as the surface protective film of Example 1 above. Surface protective films of Comparative Examples 1 to 4. In addition, in the surface protective films of Examples 1 to 6 and Comparative Examples 1 to 4, the gel fraction of the adhesive layer is in the range of 95 to 100%.

[Table 1 (A) (B) (C) (D) Example 1 2EHA 70 BMA 30 8HOA 5.5 (5.20) AAc 0.2 (0.19) HX 2.0 (1.89) Example 2 2EHA 80 EMA 20 6HHA 4.5 (4.30) CEA 0.1 (0.10) HL 2.0 (1.91) Example 3 2EHA 85 MMA 15 4HBA 1.0 (0.96) HEA 3.0 (2.86) CPA 0.2 (0.19) D-140N 1.5 (1.44) Example 4 2EHA 90 MMA 10 4HBA 0.5 (0.48) HEA 4.0 (3.82) C-1 0.3 (0.29) HX 2.0 (1.91) Example 5 2EHA 80 EMA 10 MMA 10 6HHA 3.0 (2.90) C-2 0.35 (0.34) HL 2.0 (1.94) Example 6 2EHA 80 MMA 20 4HBA 2.0 (1.94) HEAA 0.5 (0.49) C-2 0.3 (0.29) HX 2.5 (2.43) Comparative example 1 2EHA 90 LMA 10 8HOA 5.5 (5.20) AAc 0.2 (0.19) HX 2.0 (1.89) Comparative example 2 2EHA 60 MMA 40 6HHA 6.5 (6.09) AAc 0.2 (0.19) L 0.2 (0.19) HX 0.1 (0.09) Comparative example 3 2EHA 100 4HBA 2.0 (1.93) AAc 1.5 (1.45) L 0.2 (0.19) Comparative example 4 2EHA 100 4HBA 1.0 (0.96) HEA 3.0 (2.88) CPA 0.2 (0.19) D-140N 1.5 (1.44)

[Table 2] (E) (F) (G) (H) (J) Example 1 AA 9 (8.51) TI 0.1 (0.09) G-1 0.9 (0.85) H-1 0.05 (0.05) J-1 0.2 (0.19) Example 2 AA 8 (7.65) FE 0.05 (0.05) G-2 0.7 (0.67) H-2 0.1 (0.10) J-2 0.5 (0.48) Example 3 AA 6.0 (5.76) FE 0.04 (0.04) G-3 1.0 (0.96) H-3 0.08 (0.08) J-3 1.0 (0.96) Example 4 AA 5.0 (4.77) TI 0.04 (0.04) G-4 0.8 (0.76) H-4 0.06 (0.06) J-4 0.5 (0.48) Example 5 AA 6.5 (6.29) FE 0.05 (0.05) G-2 0.6 (0.58) H-2 0.1 (0.01) J-2 1.0 (0.97) Example 6 ETAC 5.5 (5.35) FE 0.05 (0.05) G-2 0.4 (0.39) H-2 0.07 (0.07) J-3 1.5 (1.46) Comparative example 1 AA 9 (8.51) TI 0.1 (0.09) G-1 0.9 (0.85) H-1 0.05 (0.05) J-5 0.5 (0.47) Comparative example 2 AA 15.0 (14.06) FE 0.02 (0.02) G-3 1.0 (0.94) H-5 0.1 (0.10) J-3 0.3 (0.28) Comparative example 3 AA 5.0 (4.83) TI 0.04 (0.04) G-5 1.0 (0.97) H-6 0.05 (0.05) J-5 0.8 (0.77) Comparative example 4 AA 6.0 (5.76) FE 0.04 (0.04) G-3 1.0 (0.96) H-3 0.08 (0.08) J-3 1.0 (0.96)

In Tables 1 to 2, the weight parts of each component were calculated by assuming that the total amount of alkyl (meth)acrylate having C1 to C10 carbon atoms in the (A) alkyl group was 100 parts by weight. In addition, in Tables 1 to 2, the acrylic polymer is assumed to be 100 parts by weight. In each column of (B) to (H) and (J), the content ratio of each component is expressed by the numerical value in parentheses ( ). (parts by weight). In addition, the compound names of the abbreviated symbols of each component (A) to (H) used in Tables 1 to 2 are shown in Table 3. In addition, CORONATE (registered trademark) HX, CORONATE HL and CORONATE L are trade names of TOSOH CORPORATION, and TAKENATE (registered trademark) D-140N, D-127N and D-110N are trade names of Mitsui Chemicals Co., Ltd.

[table 3] group abbreviation symbol Compound name (A)Group 2EHA 2-ethylhexyl acrylate BMA n-butyl methacrylate EMA Ethyl methacrylate MMA Methyl methacrylate LMA Lauryl methacrylate (B)Group 8HOA 8-hydroxyoctyl acrylate 6HHA 6-hydroxyhexyl acrylate 4HBA 4-hydroxybutyl acrylate HEA 2-hydroxyethyl acrylate HEAA N-Hydroxyethylacrylamide (C)Group AAC acrylic acid CEA Carboxyethyl acrylate CPA carboxypentyl acrylate C-1 2-Methacryloyloxyethyl maleate C-2 Acryloxyethyl succinate (D)Group HX CORONATE HX (HDI isocyanate body) HL CORONATE HL (HDI adduct) D-140N TAKENATE D-140N (IPDI adduct) L CORONATE L(TDI adduct) (E)Group AA Acetyl acetone AHr Acetoethyl acetate (F)Group TI Titanium triacetyl acetonate FE Tris(2,4-pentanedione)iron(III) (G)Group G-1 3-Methyl-1-octylpyridinium nonafluorobutanesulfonate G-2 1-Propyl-3-methylpyridinium nonafluorobutanesulfonate G-3 n-Octylpyridinium trifluoromethanesulfonate G-4 1-Octyl-3-methylpyridinium trifluoromethanesulfonate G-5 Trin-butylammonium bistrifluoromethanesulfonium imide salt (H)Group H-1 Polyether modified siloxane compound (HLB=7) H-2 Polyether modified siloxane compound (HLB=9) H-3 Polyether modified siloxane compound (HLB=12) H-4 Polyether modified siloxane compound (HLB=8) H-5 Polyether modified siloxane compound (HLB=16) H-6 Polyether modified siloxane compound (HLB=5)

Among (G) antistatic agents, G-1 to G-4 are ionic compounds whose melting point is 25°C or more and 80°C or less and is solid at normal temperature. G-5 is an ionic compound whose melting point exceeds 80°C and is solid at normal temperature. In addition, in the (H) polyether-modified siloxane compound, the weight average molecular weight of H-1 to H-6 is 10,000 or less.

Table 4 shows the composition and molecular weight (Mw) of the monomers constituting the second acrylic polymer shown in column (J) of Table 2. In addition, the compound names of the abbreviations of each component used in Table 4 are shown in Table 5. In Table 4, the weight part of each component was calculated|required, assuming that the total of (a) was 100 weight part. Furthermore, in each column of (b) to (c), the numerical value in parentheses ( ) represents the content ratio (parts by weight) obtained by assuming that the total amount of the second acrylic polymer is 100 parts by weight.

[Table 4] (a) (b) (c) molecular weight J-1 2EHA 100 8HOA 8 (6.50) I-2 15 (12.20) 600,000 J-2 BA 100 6HHA 6 (5.26) I-1 8 (7.01) 550,000 J-3 2EHA 80 MA 20 4HBA 7 (5.74) I-3 15 (12.30) 650,000 J-4 2EHA 100 HEA 10 (8.33) I-1 10 (8.33) 400,000 J-5 2EHA 100 6HHA 3 (2.54) I-4 15 (12.71) 10,000

[table 5] group abbreviation symbol Compound name (a)Group 2EHA 2-ethylhexyl acrylate BA n-butyl acrylate MA Methyl acrylate (b)Group 8HOA 8-hydroxyoctyl acrylate 6HHA 6-hydroxyhexyl acrylate 4HBA 4-hydroxybutyl acrylate HEA 2-hydroxyethyl acrylate (c)Group I-1 Polypropylene glycol monoacrylate (n=12) I-2 Methoxy polyethylene glycol acrylate (n=8) I-3 Methoxy polyethylene glycol methacrylate (n=9) I-4 Methoxy polyethylene glycol methacrylate (n=23)

(c) Among the polyolefin-based glycol chain-containing mono(meth)acrylate monomers, I-1 to I-3 are monomers whose diester component is 0.2wt% or less, and I-4 is the diester group. Divided into 0.8wt% monomer. The value of n represents the average number of repeating units of the alkylene oxide group.

＜Test methods and evaluation＞ The surface protective films in Examples 1 to 6 and Comparative Examples 1 to 4 were cured for 7 days in an atmosphere of 23° C. and 50% RH, respectively, and then evaluated by the following test method.

＜Test method for adhesion＞ Peel off the release film, and attach the surface protective film with the adhesive layer exposed to the surface of the polarizer through the adhesive layer. After leaving it for 1 day, perform an autoclave treatment at 50°C and 5 atmospheres for 20 minutes, and further heat it in the room. After leaving it at room temperature for 12 hours, it was used as a sample for measuring adhesion. Using a tensile testing machine, peel the measurement sample in the 180° direction at low speed (0.3m/min) or high speed (30m/min), and the measured peeling strength is regarded as the adhesive force. Here, the protective layer of the polarizer of the polarizer is polymethylmethacrylate (PMMA) with an AG-LR treatment layer.

＜Test method for surface resistivity＞ After curing the surface protective film and before attaching it to the polarizer, the release film was peeled off to expose the adhesive layer, and the resistivity of the adhesive layer was measured using a resistivity meter HIRESTA UP-HT450 (manufactured by Mitsubishi Chemical Analytech Co., Ltd.). Surface resistivity.

<Test method for peeling electrostatic voltage> The release film is peeled off, and the surface protective film exposing the adhesive layer is bonded to a polarizing plate having a low refractive index layer formed by using a composition for forming a low refractive index layer containing fluoride. On the glued surface. Using high-precision electrostatic sensors SK-035 and SK-200 (manufactured by KEYENCE CORPORATION), the voltage (electrostatic voltage) generated by charging the adherend when the surface protective film is peeled off 180° at a stretching speed of 30m/min is measured. The maximum value of the measured values was defined as the peeling electrostatic voltage.

＜Test method for anti-pollution performance＞ Using a laminating machine, the polarizing plate that has been subjected to low-reflection (LR) surface treatment is bonded to one side of the glass plate through an adhesive layer (double-sided adhesive tape). Then, a surface protection film is bonded to the surface of the polarizing plate using a bonding machine. After being attached to the adherend, place it in an atmosphere with a temperature of 60°C and a humidity of 90% RH for 2 days (48 hours). After taking it out from the atmosphere for 1 day, peel off the surface protective film and visually observe the surface of the polarizer. pollution status. Regarding the criteria for judging the anti-pollution performance, the surface of the polarizing plate is evaluated as "○" if there is no contamination, "△" if there is slight contamination, and "×" if there is contamination.

Table 6 shows the evaluation results of the surface protective films of Examples 1 to 6 and Comparative Examples 1 to 4. "Surface resistivity" is expressed by writing "m×10 ⁺ⁿ " as "mE+n" (where m is an arbitrary real value and n is a positive integer). The "anti-pollution performance" column indicates the material (TAC, PMMA, PET) and surface treatment (untreated, AG treated, LR treated, AR treated, AG-LR treated) of the protective layer of the polarizer of the polarizer used in the test. . Plain in "surface treatment" means untreated.

[Table 6] Adhesion (N/25mm) surface resistivity Stripping electrostatic voltage Anti-pollution properties 0.3m/min 30m/min (Ω/□) (kV) PMMA LR PETAG-LR PMMA AG-LR TAC Plain TAC AG Example 1 0.04 0.5 4.84E+10 0.2 ○ ○ ○ ○ ○ Example 2 0.04 0.5 8.24E+10 0.2 ○ ○ ○ ○ ○ Example 3 0.05 0.6 4.89E+10 0.1 ○ ○ ○ ○ ○ Example 4 0.04 0.4 7.34E+10 0.2 ○ ○ ○ ○ ○ Example 5 0.04 0.5 6.35E+10 0.1 ○ ○ ○ ○ ○ Example 6 0.05 0.6 6.47E+10 0.2 ○ ○ ○ ○ ○ Comparative example 1 0.04 0.5 3.85E+10 0.2 ○ △ △ ○ ○ Comparative example 2 0.13 0.2 2.11E+10 0.2 ○ ○ △ ○ ○ Comparative example 3 0.06 1.2 8.90E+10 0.6 × × × △ ○ Comparative example 4 0.06 0.8 5.62E+10 0.4 △ ○ × ○ ○

The adhesion force of the surface protective films of Examples 1 to 6 to the polarizing plate as the adherend at a low peeling speed of 0.3m/min is 0.01~0.1N/25mm, and at a high speed peeling speed of 30m/min The adhesive force is 1.0N/25mm or less, so the adhesive performance is excellent by balancing the adhesive force at low peeling speed and high peeling speed. In addition, the surface resistivity of the adhesive layer of the surface protective film of Examples 1 to 6 is 1.0×10 ⁺¹² Ω/□ or less, and the adhesive layer is formed using a composition for forming a low refractive index layer containing fluoride. The peeling electrostatic voltage of the low refractive index layer is in the range of +0.3~-0.3kV, and the antistatic performance is excellent. Further, after the surface protective films of Examples 1 to 6 were attached to the adherend, they were placed in an atmosphere with a temperature of 60° C. and a humidity of 90% RH for 48 hours. After taking them out from the atmosphere and passing for 1 day, the adherends were treated. Various polarizing plates of sticky materials are also free of pollution and have excellent anti-pollution properties. That is, based on the evaluation results shown in Table 6, it was confirmed that the surface protective films of Examples 1 to 6 can solve the technical problems of the present invention.

The surface protective film of Comparative Example 1 (the Tg of the copolymerized monofunctional methacrylate monomer in the first acrylic polymer is less than 0° C.) has poor anti-fouling performance against adherends other than TAC. In addition, the surface protective film of Comparative Example 2 (the first acrylic polymer contains too much copolymerized hydroxyl-containing monomer) has high adhesion at a low peeling speed and poor anti-pollution performance against PMMA. In addition, the surface protective film of Comparative Example 3 (the first acrylic polymer does not contain a methacrylate monomer with a Tg of 0°C or higher, and the proportion of a carboxyl group-containing monomer is too high, and the melting point of the antistatic agent exceeds 80°C) The adhesion force at high peeling speed is high, the peeling electrostatic voltage is high, and the anti-pollution performance is poor. In addition, compared with the surface protective film of Example 3, the surface protective film of Comparative Example 4 (in Tables 1 and 2, the component (A) of Comparative Example 4 does not contain methacrylate monomers with a Tg of 0°C or higher. Except for the body, it is the same as the components (B) to (H) and (J) of Example 3). The adhesive force is large at a high peeling speed, the peeling electrostatic voltage is high, and the anti-pollution performance against PMMA is poor. Comparing the performance of the surface protective film of Comparative Example 4 and the surface protective film of Example 3, it is clear that the adhesive composition of the present invention contains monofunctional methacrylic acid whose Tg of the homopolymer is 0° C. or higher. One or more types of ester monomers help achieve both (1) a balance of adhesion at low and high peeling speeds and (2) anti-pollution properties. In addition, as shown above, the surface protective films of Comparative Examples 1 to 4 cannot solve the technical problems of the present invention.

without.

without.

without.

Claims (16)

An adhesive composition containing a first acrylic polymer, a cross-linking agent, a cross-linking retardant, a cross-linking catalyst, and an antistatic agent, characterized in that the first acrylic polymer copolymerizes the following substances Acrylic polymer composed of a copolymer with an acid value of 0.1 to 1.0 and a weight average molecular weight of more than 300,000 and less than 1,000,000: a total of 100 parts by weight of the (A) alkyl group has a carbon number of C1 to C10 At least 2 or more kinds of (meth)acrylic acid alkyl esters, a total of 1.0 to 6.0 parts by weight of at least one or more of (B) hydroxyl-containing copolymerizable monomers, and a total of 0.01 to 0.6 parts by weight of (C ) at least 1 or more kinds of copolymerizable monomers containing carboxyl groups, and at least 2 or more kinds of (meth)acrylic acid alkyl esters whose carbon atoms in the (A) alkyl group are C1 to C10, in a total of 100 parts by weight , containing 2-ethylhexyl acrylate in a proportion of 50 parts by weight or more, and 1 of the monofunctional methacrylate monomers whose Tg of the homopolymer is 0°C or above in a total proportion of 5 to 40 parts by weight. More than one kind, the monofunctional methacrylate monomer with a Tg of the homopolymer being 0° C. or above is selected from the group consisting of n-butyl methacrylate, isobutyl methacrylate, second butyl methacrylate, methyl The adhesive composition contains at least one compound from the group consisting of tert-butyl acrylate, n-propyl methacrylate, isopropyl methacrylate, ethyl methacrylate, and methyl methacrylate. The crosslinking agent includes a trifunctional or higher isocyanate compound, a crosslinking catalyst other than a tin compound as the crosslinking catalyst, and an ionic compound with a melting point of 25 to 80° C. as the antistatic agent. The adhesive composition according to claim 1, wherein an adhesive layer obtained by cross-linking the adhesive composition is laminated to a thickness of 15 μm on one side of a polyester film having a thickness of 38 μm. After the protective film is attached to the surface of the polarizing plate, when the surface protective film is peeled off from the polarizing plate, the adhesive force at a low peeling speed of 0.3m/min is 0.01~0.1N/25mm, and at a speed of 30m/min high The adhesion force at the quick peeling speed is 1.0N/25mm or less. The adhesive composition according to claim 1 or 2, wherein the adhesive composition further contains a second acrylic polymer, and the second acrylic polymer is: the number of carbon atoms of the alkyl group in (a) is At least one or more of C1 to C18 (meth)acrylate monomers, (b) at least one or more of hydroxyl-containing copolymerizable monomers, and (c) polyalkenyl glycol chain-containing mono( A copolymer obtained by copolymerizing at least one or more of the meth)acrylate monomers, and at least two of the alkyl (meth)acrylates having C1 to C10 carbon atoms in the alkyl group (A) The adhesive composition contains the second acrylic polymer in a proportion of 0.1 to 5.0 parts by weight based on a total of 100 parts by weight of the above. The adhesive composition according to claim 1 or 2, wherein the adhesive composition is an adhesive composition used to form an adhesive layer used in a surface protective film for a polarizing plate, and the polarizer of the polarizing plate is The protective layer is one selected from the group consisting of TAC-based films, PMMA-based films, and PET-based films, and the surface treatment performed on the surface of the protective layer of the polarizer of the polarizer is selected from untreated, AG treated , LR processing, AR processing, AG-LR processing, AG-AR processing, one of the groups. The adhesive composition as described in claim 1 or 2, wherein the cation of the ionic compound with a melting point of 25 to 80°C is pyridinium, and the adhesive composition is The product contains the antistatic agent as an essential component in a proportion of 0.01 to 10 parts by weight. The adhesive composition according to claim 1 or 2, wherein the adhesive layer formed by cross-linking the adhesive composition has a surface resistivity of 1.0×10 ⁺¹² Ω/□ or less, and the adhesive layer has a resistance to The peeling electrostatic voltage of the low refractive index layer formed using a composition for forming a low refractive index layer containing a fluorine compound is in the range of +0.3 to -0.3 kV. After the adhesive layer is bonded to the polarizer, the temperature is After being placed in an atmosphere of 60°C and 90% RH for 2 days, it is taken out and peeled off after 1 day without contamination. The surface base material of the polarizer is selected from TAC film, PMMA film, and PET film. One of the groups, and the surface treatment performed on the surface of the surface substrate is 1 selected from the group consisting of untreated, AG treated, LR treated, AR treated, AG-LR treated, and AG-AR treated. species. The adhesive composition according to claim 1 or 2, wherein the (B) hydroxyl-containing copolymerizable monomer is selected from the group consisting of 8-hydroxyoctyl (meth)acrylate and 6-hydroxyhexyl (meth)acrylate. Ester, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, N-hydroxy(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N- At least one of the compound group consisting of hydroxyethyl (meth)acrylamide, the (C) carboxyl-containing copolymerizable monomer is selected from (meth)acrylic acid, carboxyethyl (meth)acrylate , Carboxypentyl (meth)acrylate, 2-(meth)acryloxyethyl hexahydrophthalate, 2-(meth)acryloxypropylhexahydrophthalate acid ester, 2-(meth)acryloxyethyl phthalate, 2-(meth)acryloxyethyl succinate, 2-(meth)acryloxyethyl At least one of the compound group consisting of maleate, carboxyl polycaprolactone mono(meth)acrylate, and 2-(meth)acryloxyethyl tetrahydrophthalate. The adhesive composition as described in claim 1 or 2, wherein the cross-linking retardant is a compound of keto-enol tautomer, and is 0.1 to 100 parts by weight of the first acrylic polymer. The crosslinking retardant is contained in a proportion of 300 parts by weight, and the crosslinking catalyst is at least one metal chelate compound selected from the group consisting of aluminum chelate compounds, titanium chelate compounds, and iron chelate compounds, relative to 100 parts by weight of the first acrylic polymer contains 0.001 to 0.5 parts by weight The weight ratio of the cross-linking catalyst and the cross-linking retardant/cross-linking catalyst is 80 to 1000. The adhesive composition as claimed in claim 1 or 2, wherein the adhesive composition contains an HLB value of 6 to 12 in a proportion of 0.01 to 0.5 parts by weight relative to 100 parts by weight of the first acrylic polymer. And the polyether modified siloxane compound has a weight average molecular weight of less than 10,000. The adhesive composition according to claim 3, wherein the second acrylic polymer is: a (meth)acrylate with a carbon number of C1 to C18 in the (a) alkyl group for a total of 100 parts by weight. At least one or more of the monomers, and a total of 2.0 to 12.0 parts by weight of (b) at least one or more hydroxyl-containing copolymerizable monomers, and a total of 1 to 30 parts by weight of (c) a polyolefin-containing diol The (B) copolymer contained in the first acrylic polymer is a copolymer with a weight average molecular weight exceeding 300,000 and not exceeding 800,000, which is obtained by copolymerizing at least one of the chain mono(meth)acrylate monomers. ) The total weight part of at least one or more copolymerizable monomers containing hydroxyl groups relative to a total of 100 parts by weight of the first acrylic polymer is the same as the value (B-1) contained in the second acrylic polymer. The ratio (b-1) of the total weight parts of at least one or more of the (b) hydroxyl-containing copolymerizable monomers to the total 100 weight parts of the second acrylic polymer /(B-1) is in the range of 1.0~2.0. The adhesive composition according to claim 3, wherein the average repeating unit of the alkylene oxide group constituting the polyolefin glycol chain in the mono(meth)acrylate monomer containing the polyolefin glycol chain is The number is 3 to 14, the diester component in the polyolefin-based glycol chain-containing mono(meth)acrylate monomer is less than 0.2%, and in 100 parts by weight of the second acrylic polymer, A proportion of 1 to 50 parts by weight is selected from the group consisting of polyolefin glycol mono(meth)acrylate, methoxy polyolefin glycol (meth)acrylate, and ethoxy polyolefin glycol (methyl) At least one kind in the group of acrylates is used as the mono(meth)acrylate monomer containing a polyalkenyl glycol chain. An adhesive film characterized in that an adhesive layer obtained by cross-linking the adhesive composition according to any one of claims 1 to 11 is laminated on one side of a resin film. A surface protection film using the adhesive film according to claim 12. A surface protection film for a polarizing plate using the adhesive film according to claim 12. An optical film with an adhesive layer, in which an adhesive layer obtained by cross-linking the adhesive composition according to any one of claims 1 to 11 is laminated on at least one surface of the optical film. The adhesive film according to claim 121, wherein an antistatic treatment and an antifouling treatment are performed on one side of the resin film opposite to the side on which the adhesive layer is formed.