KR102311150B1 - Adhesive composition and surface-protective film - Google Patents

Abstract

The present invention provides a pressure-sensitive adhesive composition and a surface protection film having an excellent balance of adhesive force at a low peel rate and a high peel rate, and excellent adhesion performance having stain resistance, and excellent antistatic performance without deterioration over time. (A) a (meth)acrylic acid ester monomer having an alkyl group having C1-C18 carbon atoms, (B) a copolymerizable monomer containing a hydroxyl group, and (C) a copolymerizable monomer containing a carboxyl group having an acid value of 0.1 to 1.0 It contains the acrylic polymer of the copolymer, and (A) contains 2-ethylhexyl acrylate in a ratio of 70 parts by weight or more among 100 parts by weight of a (meth)acrylic acid ester monomer having a C1-C18 alkyl group, The crosslinking agent is (D) a trifunctional or more isocyanate compound, and the antistatic agent is an ionic compound having a melting point of 25 to 50°C having an anion in which the number of fluorine atoms is F7 or more.

Description

An adhesive composition and a surface protection film {ADHESIVE COMPOSITION AND SURFACE-PROTECTIVE FILM}

The present invention relates to a pressure-sensitive adhesive composition containing an antistatic agent and a surface protection film. More specifically, by sticking to the polarizing plate constituting the liquid crystal display, the adhesive composition and the surface protection using the excellent adhesive performance for a surface protection film used to protect the surface of the polarizing plate and excellent antistatic performance without deterioration over time it's a film

Conventionally, in the manufacturing process of optical members, such as a polarizing plate which is a member which comprises a liquid crystal display, the surface protection film for protecting the surface of an optical member temporarily is affixed. Such a surface protection film is used only in the process of manufacturing an optical member, and peels and removes from an optical member at the time of mounting an optical member to a liquid crystal display. Since the surface protection film for protecting the surface of such an optical member is used only in a manufacturing process, generally it may call a process film.

Thus, the surface protection film used in the process of manufacturing an optical member has an adhesive layer formed in one side of the polyethylene terephthalate (PET) resin film which has optical transparency. The release film by which the release process was carried out for protecting the adhesive layer is pasted together on an adhesive layer until it is made to bond to an optical member.

Moreover, optical members, such as a polarizing plate, are the state which bonded the surface protection film, and receive the product inspection accompanying optical evaluation, such as the display ability of a liquid crystal display board, hue, contrast, and foreign material mixing. For this reason, as a performance requested|required with respect to a surface protection film, that bubble, a foreign material, and the low molecular-weight component of an adhesive composition do not adhere to an adhesive layer, ie, having stain resistance is calculated|required.

In addition, when peeling the surface protection film from an optical member such as a polarizing plate, there is a concern that peeling charging caused by static electricity generated when the pressure-sensitive adhesive layer is peeled from an adherend affects the failure of the electric control circuit of the liquid crystal display. . For this reason, it is calculated|required that an adhesive layer has the outstanding antistatic performance.

In recent years, as a polarizer protective layer (sometimes referred to as a protective film) of a polarizing plate, in addition to conventional triacetyl cellulose (TAC), acrylic resins such as polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), etc. When peeling off the surface protection film of a polarizing plate, such as polyester-type resin, a cyclic olefin type polymer, and polycarbonate, adoption of the material which tends to generate|occur|produce peeling charging is expanding. For this reason, the thing excellent in the antistatic performance calculated|required of the adhesive layer for surface protection films of a polarizing plate compared with the prior art is required.

Moreover, when finally peeling a surface protection film from optical members, such as a polarizing plate, being able to peel quickly is calculated|required. It is calculated|required that there are few changes in adhesive force also with a peeling speed so that what is called a high-speed peeling may also peel quickly.

As described above, in recent years, as the required performance for the pressure-sensitive adhesive layer constituting the surface protection film, (1) balancing the adhesive force in the low-speed peeling rate and the high-speed peeling rate, (2) having stain resistance, (3) The excellent antistatic performance etc. are calculated|required from the point of the ease of use in using a surface protection film.

However, although each of these (1)-(3) which is the performance requested|required with respect to the adhesive layer which comprises a surface protection film can satisfy each individual requested|required performance, (1)- which are calculated|required for the adhesive layer of a surface protection film It was a very difficult subject to satisfy all the performance requirements of (3) at the same time.

In order to solve these problems, for example, (1) balancing the adhesive force in the low-speed peeling rate and the high-speed peeling rate, (2) having stain resistance, and (3) excellent antistatic performance are as follows. Such proposals are known.

(1) Regarding balancing the adhesive force in the low-speed peeling rate and the high-speed peeling rate, the main component is a copolymer of (meth)acrylic acid alkyl ester having an alkyl group having 7 or less carbon atoms and a carboxyl group-containing copolymerizable compound, and this is a crosslinking agent In the acrylic pressure-sensitive adhesive layer formed by crosslinking with a furnace, there was a problem that, when adhered for a long period of time, the pressure-sensitive adhesive adhered to the adherend, and the synergism of the adhesive force to the adherend was large over time. In order to avoid this, it is known that a copolymer of a (meth)acrylic acid alkylester having an alkyl group having 8 to 10 carbon atoms and a copolymerizable compound having an alcoholic hydroxyl group is used, and an adhesive layer crosslinked with a crosslinking agent is formed ( Patent Document 1).

Furthermore, a small amount of a copolymer of a (meth)acrylic acid alkylester and a carboxyl group-containing copolymerizable compound is blended in the same copolymer as described above, and a pressure-sensitive adhesive layer obtained by crosslinking this with a crosslinking agent is proposed. However, they have low surface tension and, when used to protect the surface of a plastic plate with a smooth surface, there is a problem of causing peeling phenomena such as lifting due to heating during processing or storage, and re-peeling during peeling at high speed, which is a manual operation area. There was also the problem of falling off.

In order to solve these problems, a) 100 parts by weight of (meth)acrylic acid alkyl ester mainly containing (meth)acrylic acid alkyl ester having an alkyl group having 8 to 10 carbon atoms, b) 1 to 15 weight part of carboxyl group-containing copolymerizable compound and c) a copolymer of a monomer mixture obtained by adding 3 to 100 parts by weight of a vinyl ester of an aliphatic carboxylic acid having 1 to 5 carbon atoms, and a crosslinking agent equivalent to or more equivalent to the carboxyl group of the component b). It has been proposed (Patent Document 2).

In the pressure-sensitive adhesive composition described in Patent Document 2, peeling phenomena such as lifting during processing or storage do not occur, and the synergism with time of adhesive force is small and the re-peelability is excellent, and long-term storage, especially in a high-temperature atmosphere, It is said that it can peel again with small force even if it preserve|saves, at that time, an adhesive residue does not generate|occur|produce on a to-be-adhered body, and also when high-speed peeling is performed, it is said that it can peel again with a small force.

In addition, (2) with respect to those having stain resistance, 0 parts by mass or more and less than 0.5 parts by mass of a carboxyl group-containing monomer, 0.6 to 9 parts by mass of a hydroxyl group-containing (meth)acrylic monomer, and 99.4 to 90.5 parts by mass of a (meth)acrylic acid ester monomer. 100 parts by mass of a (meth)acrylic copolymer having a weight average molecular weight of 100,000 or more and less than 1,000,000; And a pressure-sensitive adhesive composition containing 0.1 to 5 parts by mass of a carbodiimide-based crosslinking agent is disclosed (Patent Document 3).

In the pressure-sensitive adhesive composition described in Patent Document 3, a carbodiimide-based crosslinking agent is used as a crosslinking agent for the (meth)acrylic copolymer of a specific composition. For this reason, it is possible to provide the pressure-sensitive adhesive layer with a crosslinked structure capable of following the shrinkage due to pressure and temperature during autoclave treatment. For this reason, the pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition can suppress and prevent foaming even under high-temperature and high-pressure conditions (during autoclave treatment), and has excellent adhesion resistance and transparency.

Further, (3) As for the excellent antistatic performance, as a method for imparting antistatic properties to the surface protection film, a method of incorporating an antistatic agent into the base film and the like are disclosed. Examples of the antistatic agent include (a) quaternary ammonium salts, pyridinium salts, and various cationic antistatic agents having cationic groups such as primary to tertiary amino groups, (b) sulfonate groups, sulfate groups, phosphoric acid groups. Anionic antistatic agents having anionic groups such as ester bases and phosphonate groups, (c) amphoteric antistatic agents such as amino acids and aminosulfate esters, (d) aminoalcohols, glycerin, polyethylene glycol, etc. An on-type antistatic agent, (e) a high molecular weight antistatic agent as described above, etc. are disclosed (patent document 4).

Moreover, in recent years, making a base film contain such an antistatic agent, or making it contain in an adhesive layer directly without apply|coating to the surface of a base film is proposed.

Further, an antistatic pressure-sensitive adhesive composition in which a salt having an anion having a fluoro group and a sulfonyl group is dispersed, wherein the salt having an anion having a fluoro group and a sulfonyl group is a polyether ester containing a polyether group in the main chain. An antistatic pressure-sensitive adhesive composition, which is dispersed in a dissolved state in a plasticizer, is disclosed (Patent Document 5).

In the pressure-sensitive adhesive composition described in Patent Document 5, as a plasticizer, a mono or dicarboxylic acid having a saturated or unsaturated acyclic hydrocarbon group and an alcohol having an acyclic hydrocarbon group having 1 to 20 carbon atoms are used. The use of a plasticizer composed of an ester in which the unsaturated group in the hydrocarbon group is epoxidized is disclosed. The mono- or dicarboxylic acid having such a saturated or unsaturated acyclic hydrocarbon group has a carbon number close to the carbon number of the acrylic monomer constituting the acrylic copolymer used in the pressure-sensitive adhesive layer, thereby improving compatibility with the antistatic pressure-sensitive adhesive composition, In order to hold|maintain preferably in a plasticizer acrylic type antistatic adhesive composition, it is said that bleed-out is suppressed.

Japanese Laid-Open Patent Publication No. 63-225677 Japanese Laid-Open Patent Publication No. 11-256111 Japanese Patent Laid-Open No. 2011-122054 Japanese Laid-Open Patent Publication No. 11-070629 Japanese Laid-Open Patent Publication No. 2014-118469

As described above, in the prior art, as the required performance for the pressure-sensitive adhesive layer constituting the surface protection film, balancing the adhesive force in the low-speed peeling rate and the high-speed peeling rate, having stain resistance, excellent antistatic performance, etc. are required. has been However, although it was possible to satisfy each individual requested|required performance, it was not able to satisfy all the requested|required performance requested|required of the adhesive layer of a surface protection film at the same time.

The present invention has been made in view of the above circumstances, and has an excellent balance of adhesive force in a low-speed peeling rate and a high-speed peeling rate, and excellent adhesion performance having stain resistance, and an adhesive composition having excellent antistatic performance without deterioration over time and It is made into a subject to provide a surface protection film.

In a pressure-sensitive adhesive composition having antistatic performance and a surface protection film using the same, the relationship between antistatic performance and stain resistance to an adherend is a trade-off relationship, and it is extremely difficult to improve stain resistance while maintaining antistatic performance. It was difficult.

By the way, the inventors of the present invention have a copolymer obtained by copolymerizing a copolymerizable monomer containing a carboxyl group, a polyether-containing silicone compound, and an anion having a number of fluorine atoms of F7 or more (for example, a nonafluorobutanesulfonate anion) having It discovered that the adhesive composition containing the antistatic agent which consists of an ionic compound 25 degreeC or more of melting|fusing point could solve this subject.

In order to solve the above problems, the present invention is a pressure-sensitive adhesive composition containing an antistatic agent and a crosslinking agent, wherein the pressure-sensitive adhesive composition contains (A) a (meth)acrylic acid ester monomer having C1-C18 carbon atoms in the alkyl group, and (B) a hydroxyl group It contains an acrylic polymer of a copolymer having an acid value of 0.1 to 1.0 obtained by copolymerizing a copolymerizable monomer and (C) a copolymerizable monomer containing a carboxyl group, wherein the acrylic polymer is the (A) alkyl group having C1-C18 carbon atoms. Among 100 parts by weight of the (meth)acrylic acid ester monomer, 2-ethylhexyl acrylate is contained in a ratio of 70 parts by weight or more, the glass transition temperature of the acrylic polymer is 0° C. or less, and the crosslinking agent is (D) 3 It is a functional or more isocyanate compound, wherein the antistatic agent is an ionic compound having a melting point of 25 to 50° C. consisting of a cation and an anion having an anion in which the number of fluorine atoms is F7 or more, and the pressure-sensitive adhesive composition further comprises (E) a crosslinking retardant; (F) A crosslinking catalyst other than a tin compound is contained as a crosslinking catalyst, The adhesive composition characterized by the above-mentioned is provided.

The pressure-sensitive adhesive composition of the present invention is a pressure-sensitive adhesive composition for a surface protection film bonded to a polarizer protective layer of a polarizing plate, wherein the polarizer protective layer of the polarizing plate is one selected from the group consisting of a TAC-based film, a PMMA-based film, and a PET-based film, In addition, it is preferable that the surface treatment applied to the surface of the polarizer protective layer of the polarizing plate is one selected from the group consisting of untreated, AG treatment, LR treatment, AR treatment, AG-LR treatment, and AG-AR treatment.

The anion of the ionic compound is C ₆ F ₅ (CF ₂ ) _n COO ^— , C ₆ F ₅ (CF ₂ ) _n SO ₃ ^— , C ₆ F ₅ (CF ₂ ) _n O ^— , C ₆ F ₅ O( CF ₂ ) _n SO ₃ ^― , (C ₆ F ₅ CO) ₂ N ^― , (C ₆ F ₅ CO) ₃ C ^― , (C ₆ F ₅ SO ₂ ) ₂ N ^― , (C ₆ F ₅ SO ₂ ) ₃ C ^― , (C ₆ F ₅ OSO ₂ ) ₂ N ^― , (C ₆ F ₅ OSO ₂ ) ₃ C ^― , (C ₆ F ₅ ) ₄ B ^― , CF ₃ (CF ₂ ) ₃ SO ₃ ^― It is preferable to contain at least one or more selected from the group as an anion, and to contain the ionic compound as an essential component in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the acrylic polymer.

The cation of the ionic compound is pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiouronium, piperidinium, pyrazolium, methylium, lithium, It is one type selected from the group consisting of morpholinium, and it is preferable to contain the said ionic compound as an essential component in the ratio of 0.01-10 weight part with respect to 100 weight part of the said acrylic polymer.

The surface resistivity of the pressure-sensitive adhesive layer crosslinked with the pressure-sensitive adhesive composition is 1.0×10 ⁺¹² Ω/□ or less, and the low-refractive-index layer formed using a composition for forming a low-refractive-index layer containing a fluorine compound, peeling of the pressure-sensitive adhesive layer The voltage is in the range of -0.3 to +0.3 kV, and the adhesive force in the low-speed peeling rate 0.3 m/min with respect to the polarizing plate of the adhesive layer formed by bridge|crosslinking the said adhesive composition is 0.04-0.2 N/25 mm, high-speed peeling It is preferable that the adhesive force at a speed of 30 m/min is 2.0 N/25 mm or less.

(B) the hydroxyl group-containing copolymerizable monomer is 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) at least one selected from the group consisting of acrylamide,

With respect to 100 parts by weight of the (A) alkyl group having a carbon number of C1 to C18 (meth)acrylic acid ester monomer, the (B) hydroxyl group-containing copolymerizable monomer is contained in a ratio of 0.1 to 10 parts by weight,

(C) the copolymerizable monomer containing a carboxyl group is (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- ( Meth)acryloyloxypropylhexahydrophthalic acid, 2-(meth)acryloyloxyethylphthalic acid, 2-(meth)acryloyloxyethylsuccinic acid, 2-(meth)acryloyloxyethylmaleic acid, carboxypoly at least one selected from the group consisting of caprolactone mono(meth)acrylate and 2-(meth)acryloyloxyethyltetrahydrophthalic acid,

It is preferable to contain (C) the copolymerizable monomer containing a carboxyl group in an amount of 0.01 to 0.5 parts by weight with respect to 100 parts by weight of the (A) alkyl group having a carbon number of C1-C18 (meth)acrylic acid ester monomer. .

The (E) crosslinking retarder is a ketoenol tautomer compound, and the (E) crosslinking retarder is contained in an amount of 0.1 to 300 parts by weight based on 100 parts by weight of the acrylic polymer, and (F) crosslinking The catalyst is at least one metal chelate compound selected from the group consisting of an aluminum chelate compound, a titanium chelate compound, and an iron chelate compound, and the (F) crosslinking catalyst is used in a ratio of 0.001 to 0.5 parts by weight with respect to 100 parts by weight of the acrylic polymer. It is made to contain, and it is preferable that the ratio by weight of (E)/(F) is 80 to 1000.

It is preferable that the said adhesive composition contains the polyether modified siloxane compound whose HLB value is 6-12 and the weight average molecular weight 10000 or less with respect to 100 weight part of the said acrylic polymer in the ratio of 0.01-0.5 weight part.

The weight average molecular weight obtained by copolymerizing a (meth)acrylic acid ester monomer having an alkyl group having C1 to 18 carbon atoms and a polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer with respect to 100 parts by weight of the acrylic polymer in the pressure-sensitive adhesive composition is 10 It is preferable to contain the copolymer which is more than 10,000 and 300,000 or less in the ratio of 0.1-5.0 weight part.

The polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer has an average repeating number of alkylene oxide constituting the polyalkylene glycol chain from 3 to 14, and in the polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer The diester content is 0.2% or less, and as the polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer, polyalkylene glycol mono (meth) acrylate, methoxy polyalkylene glycol (meth) acrylate, ethoxy poly Containing at least one selected from the group consisting of alkylene glycol (meth) acrylate in a ratio of 1 to 50 parts by weight in 100 parts by weight of the copolymer having a weight average molecular weight of more than 100,000 and not more than 300,000 desirable.

In addition, the present invention provides a pressure-sensitive adhesive film characterized in that the pressure-sensitive adhesive layer crosslinked with the pressure-sensitive adhesive composition is laminated on one side of the resin film.

In addition, the present invention provides a surface protection film using the adhesive film.

In addition, the present invention provides a surface protection film for a polarizing plate in which the adhesive film is used.

Moreover, this invention provides the optical film in which the adhesive layer by which the adhesive layer which consists of the said adhesive composition is laminated|stacked on at least one surface of an optical film is provided.

In addition, the present invention provides the pressure-sensitive adhesive film on one side of the resin film, which is subjected to antistatic treatment and antifouling treatment on the opposite side to the side on which the pressure-sensitive adhesive layer is formed.

The pressure-sensitive adhesive composition according to the present invention has excellent adhesion performance and does not deteriorate over time, and has excellent anti-static performance against peeling, as compared with the conventional pressure-sensitive adhesive composition for surface protection films.

In particular, the surface protection film according to the present invention is a low-refractive-index layer formed using a composition for forming an antifouling layer containing a fluorine compound or a low-refractive-index layer containing a fluorine compound, in which an adherend is laminated on the surface of an optical film. In the case of an adherend having a surface protection film according to the prior art, it has excellent adhesion performance and does not deteriorate over time, and has excellent peeling antistatic performance. That is, the surface protection film according to the present invention has a remarkable effect on both antistatic performance and stain resistance.

That is, since the pressure-sensitive adhesive composition according to the present invention and the surface protection film using the same have excellent adhesive performance, do not deteriorate over time, and have excellent peeling and antistatic performance, industrial use value is extremely high.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated based on preferable embodiment.

The pressure-sensitive adhesive composition of the present embodiment is a pressure-sensitive adhesive composition containing an antistatic agent and a crosslinking agent, the pressure-sensitive adhesive composition is (A) a (meth) acrylic acid ester monomer having C1-C18 carbon atoms in the alkyl group, and (B) copolymerizable containing a hydroxyl group It contains an acrylic polymer of a copolymer having an acid value of 0.1 to 1.0 by copolymerizing a monomer and a copolymerizable monomer containing a carboxyl group (C), and the acrylic polymer is (A) C1 to C18 in the alkyl group (meth) Among 100 parts by weight of the acrylic acid ester monomer, 2-ethylhexyl acrylate is contained in a ratio of 70 parts by weight or more, the glass transition temperature of the acrylic polymer is 0° C. or less, and the crosslinking agent is (D) trifunctional or more isocyanate compound, wherein the antistatic agent is an ionic compound having a melting point of 25 to 50° C. comprising a cation and an anion having an anion in which the number of fluorine atoms is F7 or more, and the pressure-sensitive adhesive composition further comprises (E) a crosslinking retarder, (F) It is characterized by containing a crosslinking catalyst other than a tin compound as a crosslinking catalyst.

The acrylic polymer used for the adhesive composition of this embodiment is a main polymer of an adhesive composition, and a glass transition temperature is 0 degreeC or less. Further, the acrylic polymer is preferably (A) a copolymer containing, as a main component, a (meth)acrylic acid ester monomer having C1-C18 carbon atoms in the alkyl group.

(A) Examples of (meth)acrylic acid ester monomers having C1-C18 alkyl group carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylic Rate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) ) acrylates and the like. The alkyl group of the alkyl (meth)acrylate monomer may be linear, branched or cyclic.

The acrylic polymer used in the pressure-sensitive adhesive composition of the present embodiment contains (A) 2-ethylhexyl acrylate in a ratio of 70 parts by weight or more among 100 parts by weight of the (meth)acrylic acid ester monomer having C1-C18 alkyl groups. It is desirable to do

The acrylic polymer used for the adhesive composition of this embodiment contains the copolymerizable monomer containing (B) a hydroxyl group. (B) Examples of the hydroxyl group-containing copolymerizable monomer include 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-hydroxy At least one selected from the group consisting of ethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, etc. desirable.

It is preferable to contain (B) a hydroxyl group-containing copolymerizable monomer in a proportion of 0.1 to 10 parts by weight with respect to 100 parts by weight of the (A) alkyl group having a carbon number of C1-C18 (meth)acrylic acid ester monomer, 1.6 It is more preferable to contain in the ratio of -8.5 weight part, and it is especially preferable to contain it in the ratio of 2.1 to 7.5 weight part.

The acrylic polymer used for the adhesive composition of this embodiment contains the copolymerizable monomer containing (C) a carboxyl group. (C) As a copolymerizable monomer containing a carboxyl group, (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (meth)acryloyloxypropylhexahydrophthalic acid, 2-(meth)acryloyloxyethylphthalic acid, 2-(meth)acryloyloxyethylsuccinic acid, 2-(meth)acryloyloxyethylmaleic acid, carboxy It is preferable that it is at least 1 sort(s) selected from the compound group which consists of polycaprolactone mono(meth)acrylate, 2-(meth)acryloyloxyethyl tetrahydrophthalic acid, etc.

It is preferable to contain (C) a copolymerizable monomer containing a carboxyl group in a ratio of 0.01 to 0.5 parts by weight with respect to 100 parts by weight of the (A) alkyl group having a carbon number of C1-C18 (meth)acrylic acid ester monomer, 0.01 It is more preferable to contain in a ratio of -0.45 weight part, and it is especially preferable that it contains in a ratio of 0.01-0.4 weight part.

The manufacturing method of the acrylic polymer contained in the adhesive composition which concerns on this embodiment is not specifically limited, Well-known polymerization methods, such as a solution polymerization method and an emulsion polymerization method, can be used suitably. As for the weight average molecular weight of the copolymer of an acryl-type polymer, 500,000-3 million are mentioned, for example. It is preferable that the acid value of an acrylic polymer is 0.1-1.0. For this reason, stain resistance can be improved. Here, "acid value" is one of the index|indexes which show content of an acid, and is represented by the mg number of potassium hydroxide required to neutralize 1 g of polymer containing a carboxyl group.

The pressure-sensitive adhesive composition according to the present embodiment contains (G) an antistatic agent. The antistatic agent (G) of the present embodiment is an ionic compound comprising a cation and an anion having an anion in which the number of fluorine atoms is F7 or more. The ionic compound has a melting point of 25 to 50°C, and is preferably a solid at room temperature (eg, 25°C). It is preferable to contain the said ionic compound as an essential component in the ratio of 0.01-10 weight part with respect to 100 weight part of said acrylic polymers.

In addition, when it is necessary to increase the antistatic performance of the pressure-sensitive adhesive layer and reduce the lower limit of the surface resistivity to 1.0 × 10 ⁺¹⁰ Ω/□ or less, 0.01 to 15 of the ionic compound is added to 100 parts by weight of the acrylic polymer. It is more preferable to contain it in the ratio of a weight part.

Examples of the anion of the ionic compound include C ₆ F ₅ (CF ₂ ) _n COO ^— , C ₆ F ₅ (CF ₂ ) _n SO ₃ ^— , C ₆ F ₅ (CF ₂ ) _n O ^— , C ₆ F ₅ O(CF ₂ ) _n SO ₃ ^― , (C ₆ F ₅ CO) ₂ N ^― , (C ₆ F ₅ CO) ₃ C ^― , (C ₆ F ₅ SO ₂ ) ₂ N ^― , (C ₆ F ₅ SO ₂ ) ₃ C ^― , (C ₆ F ₅ OSO ₂ ) ₂ N ^― , (C ₆ F ₅ OSO ₂ ) ₃ C ^― , (C ₆ F ₅ ) ₄ B ^― , CF ₃ (CF ₂ ) ₃ SO ₃ ^― at least one selected from the group consisting of Here, n is an integer of 1 or more.

Examples of the cation of the ionic compound include pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiouronium, piperidinium, pyrazolium, methylium, and at least one selected from the group consisting of lithium and morpholinium.

(G) Specific examples of the antistatic agent include methyltrioctylammonium tris(pentafluorobenzenesulfonyl)methide salt, 3-methyl-1-octylpyridinium nonafluorobutanesulfonate salt, 1 -Ethyl-3-methylimidazolium tetrakis(pentafluorophenyl)borate salt, 1-butyl-1-methylpiperidinium bis(pentafluorobenzenesulfonyl)imide salt, etc. are mentioned.

The pressure-sensitive adhesive composition according to the present embodiment further contains (D) a trifunctional or higher isocyanate compound as a crosslinking agent. (D) Trifunctional or more than trifunctional isocyanate compounds include, for example, burette-modified products and isocyanates of diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, and xylylene diisocyanate. The adduct body with trivalent or more polyols, such as an anurate modified body, trimethylol propane, and glycerol, etc. are mentioned. (D) As a ratio of a trifunctional or more than trifunctional isocyanate compound, the ratio of 0.01-5 weight part is mentioned with respect to 100 weight part of acrylic polymers, for example.

The pressure-sensitive adhesive composition according to the present embodiment may contain (E) a crosslinking retarder. (E) Examples of the crosslinking retardant include β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, and stearyl acetoacetate, acetylacetone, and 2,4-hexane and β-diketones such as dione and benzoylacetone. These are ketoenol tautomer compounds, and in the pressure-sensitive adhesive composition using a polyisocyanate compound as a crosslinking agent, by blocking the isocyanate group possessed by the crosslinking agent, excessive increase in viscosity or gelation of the pressure-sensitive adhesive composition after mixing of the crosslinking agent is suppressed, and the pressure-sensitive adhesive composition of the pressure-sensitive adhesive composition You can extend your pot life. (E) The crosslinking retardant is preferably a ketoenol tautomer compound, and particularly preferably at least one or more selected from the group consisting of acetylacetone and ethyl acetoacetate. It is preferable to contain the (E) crosslinking retarder in the ratio of 0.1-300 weight part with respect to 100 weight part of said acrylic polymers.

The adhesive composition which concerns on this embodiment may contain crosslinking catalysts other than a tin compound as (F) crosslinking catalyst. (F) The crosslinking catalyst should just be a substance which functions as a catalyst with respect to the reaction (crosslinking reaction) of the said copolymer and a crosslinking agent, when using a polyisocyanate compound as a crosslinking agent. As a crosslinking catalyst other than a tin compound, organometallic compounds, such as amine compounds, such as a tertiary amine, a metal chelate compound, an organic lead compound, and an organic zinc compound, etc. are mentioned.

(F) The metal chelate compound of the crosslinking catalyst 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-pentanedionate)iron(III), iron trisacetylacetonate, titanium trisacetylacetonate, ruthenium trisacetylacetonate, zinc bisacetylacetonate, aluminum tris Acetylacetonate, zirconium tetrakisacetylacetonate, tris(2,4-hexanedionate)iron(III), bis(2,4-hexanedionate)zinc, tris(2,4-hexanedionate)titanium, Tris(2,4-hexanedionate)aluminum, tetrakis(2,4-hexanedionate)zirconium, etc. are mentioned.

(F) The crosslinking catalyst is preferably at least one metal chelate compound selected from the group consisting of an aluminum chelate compound, a titanium chelate compound, and an iron chelate compound. It is preferable to contain the (F) crosslinking catalyst in the ratio of 0.001 to 0.5 weight part with respect to 100 weight part of said acrylic polymers.

Since the (E) crosslinking retarder has an effect of suppressing crosslinking as opposed to the (F) crosslinking catalyst, it is preferable to appropriately set the ratio of the (E) crosslinking retarder to the (F) crosslinking catalyst. In order to lengthen the pot life of an adhesive composition and to improve storage stability, it is preferable that the weight part ratio of (E)/(F) is 80-1000. 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 pressure-sensitive adhesive composition according to the present embodiment may contain (H) a polyether-modified siloxane compound as an optional component. (H) The polyether-modified siloxane compound is a siloxane compound having a polyether group, and in addition to the usual siloxane unit [-SiR ¹ ₂ -O-], a siloxane unit having a polyether group [-SiR ¹ (R ² O(R ³ O)) ) _n R ⁴ )-O-]. Here, R ¹ is one or more alkyl or aryl groups, R ² and R ³ are one or two or more alkylene groups, R ⁴ is one or more alkyl or acyl groups (terminal groups) indicates. Examples of the polyether group include polyoxyalkylene groups such as polyoxyethylene group [(C ₂ H ₄ O) _n ] and polyoxypropylene group [(C ₃ H ₆ O) _n ]. In the siloxane unit having a polyether group, the terminal of the polyether group may be an OH group (R ⁴ =H in the above formula).

(H) The polyether-modified siloxane compound is preferably a polyether-modified siloxane compound having an HLB value of 6 to 12. In addition, with respect to 100 parts by weight of the acrylic polymer, (H) polyether-modified siloxane compound is preferably contained in an amount of 0.01 to 0.5 parts by weight, more preferably 0.02 to 0.35 parts by weight, and 0.02 to 0.25 parts by weight. It is particularly preferable to be An HLB value is a hydrophilic-lipophilic balance (hydrophilic-lipophilic ratio) prescribed|regulated, for example by JISK3211 (surfactant term) etc.

The polyether-modified siloxane compound can be obtained by, for example, grafting an organic compound having an unsaturated bond and a polyoxyalkylene group to a polyorganosiloxane main chain having a silicon hydride group by hydrosilylation reaction. Specifically, dimethylsiloxane/methyl (polyoxyethylene) siloxane copolymer, dimethylsiloxane/methyl (polyoxyethylene) siloxane/methyl (polyoxypropylene) siloxane copolymer, dimethylsiloxane/methyl (polyoxypropylene) siloxane polymer, etc. can be heard

(H) By mix|blending a polyether modified siloxane compound with an adhesive composition, the adhesive force of an adhesive layer and rework performance can be improved. (H) It is preferable that the weight average molecular weight of a polyether modified siloxane compound is 10000 or less. From the viewpoint of compatibility with the acrylic polymer, the lower the HLB value and the lower the molecular weight, the better the compatibility. However, in the case of a polyether-modified siloxane compound having a low molecular weight, the HLB value is relatively high and the compatibility with the polymer is slightly low, but excellent antistatic properties this is obtained

The pressure-sensitive adhesive composition according to the present embodiment, as an optional component, a weight average molecular weight obtained by copolymerizing (meth)acrylic acid ester monomer having C1 to C18 alkyl group and (I) polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer You may contain this more than 100,000 and 300,000 or less copolymers (henceforth "copolymer B" is said) as an antistatic adjuvant. Copolymer B is preferably contained in a ratio of 0.1 to 5.0 parts by weight, more preferably in a ratio of 0.1 to 3.5 parts by weight, and is contained in a ratio of 0.1 to 2.5 parts by weight with respect to 100 parts by weight of the acrylic polymer. It is particularly preferred.

(I) The polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer may be a compound in which one hydroxyl group is esterified as a (meth)acrylic acid ester among a plurality of hydroxyl groups in polyalkylene glycol. Since the (meth)acrylic acid ester group becomes a polymerizable group, it can copolymerize with the said acrylic polymer. The polyalkylene glycol mono(meth)acrylate in which another hydroxyl group remains OH may be sufficient, and the alkoxy polyalkylene glycol mono(meth)acrylate etc. which the other hydroxyl group was converted into alkyl ether may be sufficient.

The polyalkylene glycol constituting the polyalkylene glycol chain may be a glycol compound having one or more alkylene groups, for example, polyethylene glycol, polypropylene glycol, polybutylene glycol, polyethylene glycol-poly Propylene glycol, polyethylene glycol - polybutylene glycol, polypropylene glycol - polybutylene glycol, polyethylene glycol - polypropylene glycol - polybutylene glycol, etc. are mentioned.

(I) The polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer preferably has an average repeating number of 3 to 14 alkylene oxides constituting the polyalkylene glycol chain. "Average number of repetitions of alkylene oxide" is (I) the portion of the "polyalkylene glycol chain" contained in the molecular structure of the polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer, wherein the alkylene oxide unit is is the number of repeated averages. Moreover, it is preferable that the diester content in (I) polyalkylene glycol chain containing mono(meth)acrylic acid ester monomer is 0.2 % or less. The "diester fraction in the monomer" is the content (weight%) of the polyalkylene glycol di(meth)acrylic acid ester contained in the (I) polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer.

(I) Polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomers include polyalkylene glycol mono (meth) acrylate, methoxy polyalkylene glycol (meth) acrylate, ethoxy polyalkylene glycol (meth) ) It is preferred that at least one selected from the group consisting of acrylates. The ratio of the (I) polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer in the copolymer B is preferably 1 to 50 parts by weight, and 2 to 35 parts by weight in 100 parts by weight of the copolymer B. The proportion of parts is more preferable, and the proportion of 2 to 25 parts by weight is particularly preferable.

As monomers other than the (I) polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer copolymerized in copolymer B, the (meth) acrylic acid ester monomer having an alkyl group having C1 to 18 carbon atoms and a copolymerizable monomer containing a hydroxyl group At least 1 type or more of these etc. are mentioned. As a specific example of these monomers, the (meth)acrylic-type monomer illustrated above (A) and (B) etc., respectively is mentioned. The monomer copolymerized with the copolymer B may be different from the monomer copolymerized with the acrylic polymer. The copolymer B does not need to copolymerize the copolymerizable monomer containing a carboxyl group.

The pressure-sensitive adhesive composition of the present embodiment is not limited to the above additives, and well-known additives such as surfactants, curing accelerators, plasticizers, fillers, curing retarders, processing aids, antioxidants, and antioxidants may be appropriately blended. These can be used individually or in combination of 2 or more types.

The adhesive composition of this embodiment is preferable as an adhesive composition for surface protection films bonded to the polarizer protective layer of a polarizing plate. Here, the polarizer protective layer of the polarizing plate may be one selected from the group consisting of a TAC-based film, a PMMA-based film, and a PET-based film. Here, TAC is an abbreviation of triacetyl cellulose, PMMA is polymethyl methacrylate, and PET is an abbreviation of polyethylene terephthalate.

Further, the surface treatment applied to the surface of the polarizer protective layer of the polarizing plate may be one selected from the group consisting of untreated, AG treatment, LR treatment, AR treatment, AG-LR treatment, and AG-AR treatment. Here, AG is anti-glare, LR is low reflection, and AR is anti-reflection.

The pressure-sensitive adhesive layer in which the pressure-sensitive adhesive composition of the present embodiment is crosslinked has a surface resistivity of ^{preferably 1.0×10 +12} Ω/□ or less, more preferably 5.0×10 ⁺¹¹ Ω/□ or less, and 1.0×10 ⁺¹¹ Ω/□ or less. It is especially preferable that it is the following. When the surface resistivity is large, the performance of dissipating static electricity generated when the pressure-sensitive adhesive layer is peeled from the adherend is poor. For this reason, by making the surface resistivity sufficiently small, the peeling electrification voltage which arises accompanying static electricity which generate|occur|produces when peeling an adhesive layer from a to-be-adhered body is reduced, and it can suppress that it affects a to-be-adhered body.

The peeling electrification voltage of the adhesive layer with respect to the low-refractive-index layer formed using the composition for low-refractive-index layer formation containing a fluorine compound in the adhesive layer which crosslinked the adhesive composition of this embodiment is the range of -0.3-+0.3 kV It is preferable to be mine. Examples of the fluorine compound used in the composition for forming a low refractive index layer include a fluorinated copolymer which is one or two or more polymers such as fluorinated olefins, fluorinated vinyl ethers, and fluorinated alkyl (meth) acrylates, and fluorinated alkyl group-containing silanes. Condensates, such as a compound, are mentioned. The fluorinated copolymer may be copolymerized with fluorinated monomers and non-fluorinated monomers such as olefins, vinyl ethers and (meth)acrylates. The low-refractive-index layer may be combined with a high-refractive-index layer or the like to constitute an antireflection layer.

The adhesive force in the low-speed peeling rate 0.3m/min with respect to the polarizing plate of the adhesive layer formed by bridge|crosslinking the adhesive composition of this embodiment is 0.04-0.2N/25 mm, The adhesive force in high-speed peeling rate 30m/min is 2.0N/ It is preferable that it is 25 mm or less, and it is more preferable that the adhesive force in high-speed peeling speed 30 m/min is 0.2-1.6 N/25 mm. For this reason, the performance with little change in adhesive force also with peeling speed is acquired, and it becomes possible to peel quickly also by high-speed peeling. Moreover, even when peeling the surface protection film once for re-adhesion, it does not require excessive force and it is easy to peel from a to-be-adhered body.

It is preferable that it is 95-100 %, and, as for the gel fraction of the adhesive layer formed by bridge|crosslinking the adhesive composition of this embodiment, it is more preferable that it is 97-100 %. As such, when the gel fraction is high, the adhesive force is not excessive at a low peeling rate, the elution of unpolymerized monomers or oligomers from the copolymer is reduced, and the reworkability and durability at high temperature and high humidity are improved, and the adherend is improved. contamination can be suppressed.

The adhesive film of this embodiment forms the adhesive layer formed by bridge|crosslinking the adhesive composition of this embodiment on one side or both surfaces of a resin film. Moreover, the surface protection film of this embodiment is a surface protection film formed by forming in one surface of a resin film the adhesive layer formed by bridge|crosslinking the adhesive composition of this embodiment. The adhesive composition of this embodiment is equipped with the outstanding antistatic performance, it is excellent in the balance of adhesive force in a low-speed peeling rate and a high-speed peeling rate, and has stain resistance. For this reason, it can use suitably as a use of the surface protection film of a polarizing plate.

A resin film, such as a polyester film, etc. can be used as the base film of an adhesive layer, and the release film (separator) which protects an adhesive surface.

Antistatic treatment and antifouling treatment may be given to the surface opposite to the side in which the said adhesive layer of one side of a resin film was formed. As antistatic treatment, application|coating, mixing, etc. of an antistatic agent are mentioned. As an antifouling|stain-resistant treatment, the process by a silicone type, a fluorine type mold release agent, a coating agent, silica microparticles|fine-particles, etc. is mentioned. The release film may be subjected to a release treatment with a silicone-based, fluorine-based, or long-chain alkyl-based mold release agent or the like on the surface on the side aligned with the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer.

Moreover, the optical film with an adhesive layer can be obtained by laminating|stacking the adhesive layer which bridge|crosslinked the adhesive composition of this embodiment on at least one surface of an optical film. Examples of the optical film include a polarizing film, a retardation film, an antireflection film, an anti-glare (anti-glare) film, an ultraviolet absorption film, an infrared absorption film, an optical compensation film, and a brightness improving film. As an apparatus to which an optical member is applied, a liquid crystal panel, an organic electroluminescent panel, a touch panel, etc. are mentioned.

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

Example

Hereinafter, the present invention will be specifically described with reference to Examples.

<Preparation of acrylic polymer solution>

[Example 1]

Nitrogen gas was introduced into a reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen introduction tube, and the air in the apparatus was replaced with nitrogen gas. Thereafter, a solvent (ethyl acetate) was added to the reaction apparatus together with 90 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of methyl acrylate, 5.5 parts by weight of 8-hydroxyoctyl acrylate, and 0.2 parts by weight of acrylic acid. Then, 0.1 weight part of azobisisobutyronitrile as a polymerization initiator was dripped over 2 hours, it was made to react at 65 degreeC for 6 hours, and the acrylic polymer solution used for Example 1 was obtained.

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

Except that the composition of the monomers were the same as those described in Table 1 (A) to (C), respectively, the acrylic polymer solution used in Example 1 was the same, and Examples 2 to 6 and Comparative Examples 1 to 3 were used. An acrylic polymer solution was obtained.

<Preparation of adhesive composition and surface protection film>

[Example 1]

With respect to the acrylic polymer solution of Example 1 prepared as described above, 2.0 parts by weight of a crosslinking agent (Coronate HX), 9 parts by weight of a crosslinking retarder (acetylacetone), 0.1 parts by weight of a crosslinking catalyst (Titanium trisacetylacetonate), charging 0.9 parts by weight of inhibitor (methyltrioctylammonium tris(pentafluorobenzenesulfonyl)methide salt), 0.05 parts by weight of polyether-modified siloxane compound (HLB=7), 0.2 parts by weight of copolymer B-1 (molecular weight 150,000) It was added, stirred and mixed, and the adhesive composition of Example 1 was obtained. After apply|coating this adhesive composition on the mold release film (silicone resin-coated PET film), the solvent was removed by drying at 90 degreeC, and the 20-micrometer-thick adhesive layer was obtained. Then, by transferring the adhesive layer in which the release film was formed on the opposite side to the antistatic and antifouling side of the base film (PET film with antistatic and antifouling treatment on one side), "base film / adhesive layer / release film", the surface protection film of Example 1 which has a laminated constitution was obtained.

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

Except that the composition of the additive was as described in Table 1 (D) to (H) and copolymer B, respectively, the surface protection film of Example 1 was the same as that of Examples 2 to 6 and Comparative Examples 1 to 3, respectively. A protective film was obtained.

In Table 1, the weight part of each component was calculated|required as 100 weight part of the sum total of the (A) C1-C18 (meth)acrylic acid ester monomer whose carbon number of an alkyl group is 100 weight part.

Here, in Table 1, in each column of (D), (E), (F), (G), (H), and (copolymer B), the content ratio of each component (weight Part) is shown as a numerical value in parentheses (　).

In addition, the compound names of the abbreviation|symbol of each component used in Table 1 are shown in Tables 2-3. Table 2 also contains the compound names of the abbreviations of monomers other than the (I) polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer among the component monomers of the copolymer B shown in Table 3. On the other hand, Coronate (registered trademark) HX, HL and L are trade names of Tosoh Corporation, and Takenate (registered trademark) D-140N is a trade name of Mitsui Chemicals Corporation.

(G) Of the antistatic agents, G-1 to G-4 are all ionic compounds having an anion in which the number of fluorine atoms is F7 or more, and having a melting point of 25°C or more. G-5 is an ionic compound having an anion in which the number of fluorine atoms is F5 and a solid at a melting point of 25°C or higher.

(H) All of H-1 to H-6 have a weight average molecular weight of 10000 or less among polyether-modified siloxane compounds.

(I) Among the polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomers, in I-1 to I-3, the diester content in the monomer is 0.2% or less, and in I-4, the diester content in the monomer is 0.8%. In addition, n in the column of (I) group of Table 3 is a numerical value which shows the average number of repetitions of an alkylene oxide.

<Test method and evaluation>

After aging the surface protection films in Examples 1-6 and Comparative Examples 1-3 in 23 degreeC and atmosphere of 50 %RH, respectively for 7 days, the following test method evaluated.

<Test method of adhesion>

After peeling the release film and exposing the pressure-sensitive adhesive layer, the surface protection film was bonded to the surface of the polarizing plate through the pressure-sensitive adhesive layer, left to stand for 1 day, autoclaved at 50° C., 5 atmospheres, 20 minutes, and further 12 at room temperature What was left to stand for time was made into the measurement sample of adhesive force. The obtained measurement sample was peeled at a low speed (0.3 m/min) or high speed (30 m/min) using a tensile tester in a 180 degree direction, and the measured peeling strength was made into adhesive force.

Here, the polarizer protective layer of the polarizing plate is one selected from the group consisting of triacetyl cellulose (TAC), polymethyl methacrylate (PMMA), and polyethylene terephthalate (PET).

In the LR polarizing plate and the AG-LR polarizing plate, the surface of the polarizer protective layer of the polarizing plate is subjected to a low-reflection surface treatment with a composition containing a fluorine compound.

<Test method of surface resistivity>

After aging the surface protection film, before bonding to the polarizing plate, the release film is peeled to expose the pressure-sensitive adhesive layer, and the surface resistivity of the pressure-sensitive adhesive layer is measured using a resistivity meter Hirestar UP-HT450 (manufactured by Mitsubishi Chemical Analytech). did.

<Test method of peel electrification voltage>

The surface protection film in which the release film was peeled and the adhesive layer was exposed was bonded to the polarizing plate which has a low-refractive-index layer formed using the composition for low-refractive-index layer formation containing a fluorine compound on a to-be-adhered surface. When the surface protection film is peeled 180° at a tensile speed of 30 m/min, the voltage (charged voltage) generated by the charging of the adherend is measured using high-precision electrostatic sensors SK-035 and SK-200 (manufactured by Keyence Co., Ltd.). , the maximum value of the measured value was taken as the peel electrification voltage.

<Test method for stain resistance>

The polarizing plate which gave the said low reflection (LR) surface treatment on the single side|surface of a glass plate was bonded together through the adhesive layer (double-sided adhesive tape) using the bonding machine. Then, the surface protection film was bonded together on the surface of the said polarizing plate using the bonding machine. After storing over the period of 3 days and 30 days in 23 degreeC and 50 %RH environment, the surface protection film was peeled and the contamination state on the surface of a polarizing plate was observed visually. As for the criterion for judging the stain resistance, the case of no staining was evaluated as "○", the case of slight staining as "Δ", and the presence of staining as "x" on the surface of the polarizing plate.

In Table 4, the evaluation result about the surface protection film in Examples 1-6 and Comparative Examples 1-3 is shown. "Surface resistivity" was indicated by way of the "m × 10 ^{+ n"} in "mE + n" (where, m is an arbitrary real number, n is a positive integer). The column of "polarizer protective layer of polarizing plate" shows the material and surface treatment of the polarizer protective layer of the polarizing plate used by the adhesive force test. Plain of "surface treatment" means untreated.

The surface protection films of Examples 1 to 6 had an adhesive force of 0.04 to 0.2 N/25 mm at a low peel rate of 0.3 m/min to a polarizing plate as an adherend, and an adhesive force of 2.0 N/25 mm at a high peel rate of 30 m/min. Below, it was excellent in adhesive performance.

In addition, the surface protection films of Examples 1 to 6 have a surface resistivity of the pressure-sensitive adhesive layer of 1.0 × 10 ⁺¹² Ω/□ or less, and a low-refractive-index layer formed using a composition for forming a low-refractive-index layer containing a fluorine compound. The peeling electrification voltage of the pressure-sensitive adhesive layer was in the range of -0.3 to +0.3 kV, and the antistatic performance was excellent.

In addition, the surface protection films of Examples 1 to 6 did not stain the polarizing plate as an adherend even after storage for 3 days and 30 days, and were excellent in stain resistance.

That is, the evaluation result shown in Table 4 about the surface protection film of Examples 1-6 demonstrates that the subject of this invention was solvable.

In the surface protection film of Comparative Example 1, among 100 parts by weight of the (meth)acrylic acid ester monomer having C1-C18 carbon atoms in the (A) alkyl group in the acrylic polymer contained in the pressure-sensitive adhesive composition, the ratio of 2EHA is 50 parts by weight and is small. Further, (C) the copolymerizable monomer containing a carboxyl group is not copolymerized. In addition, in the pressure-sensitive adhesive composition according to the surface protection film of Comparative Example 1, the antistatic agent contains an anion of F5 in which the number of fluorine atoms is less than F7. For this reason, the surface protection film of the comparative example 1 had the large adhesive force of an adhesive layer, the peeling electrification voltage was high, and the stain resistance was also bad.

In addition, in the surface protection film of Comparative Example 2, the acid value of the acrylic polymer included in the pressure-sensitive adhesive composition exceeded 1.0, and stain resistance was poor.

Moreover, in the surface protection film of Comparative Example 3, the antistatic agent contained in the adhesive composition contained the anion of F5 whose number of fluorine atoms is less than F7, and stain resistance was bad.

Thus, in the surface protection film of Comparative Examples 1-3, the subject of this invention could not be solved.

Claims (9)

A pressure-sensitive adhesive composition comprising an antistatic agent and a crosslinking agent,
The pressure-sensitive adhesive composition
(A) a (meth)acrylic acid ester monomer having C1-C18 carbon atoms in the alkyl group;
(B) a copolymerizable monomer containing a hydroxyl group;
(C) an acrylic polymer having an acid value of 0.1 to 1.0 obtained by copolymerizing a copolymerizable monomer containing a carboxyl group,
wherein the acrylic polymer contains (A) 2-ethylhexyl acrylate in a proportion of 70 parts by weight or more in 100 parts by weight of the (meth)acrylic acid ester monomer having C1-C18 carbon atoms in the alkyl group,
The glass transition temperature of the acrylic polymer is 0 ℃ or less,
The crosslinking agent is (D) a trifunctional or more isocyanate compound,
The antistatic agent is an ionic compound having a melting point of 25 to 50° C. comprising a cation and an anion having an anion in which the number of fluorine atoms is F7 or more, and the ionic compound is added in a ratio of 0.01 to 10 parts by weight with respect to 100 parts by weight of the acrylic polymer. A pressure-sensitive adhesive composition comprising: The method of claim 1,
The anion of the ionic compound is C ₆ F ₅ (CF ₂ ) _n COO ^— , C ₆ F ₅ (CF ₂ ) _n SO ₃ ^— , C ₆ F ₅ (CF ₂ ) _n O ^— , C ₆ F ₅ O( CF ₂ ) _n SO ₃ ^― , (C ₆ F ₅ CO) ₂ N ^― , (C ₆ F ₅ CO) ₃ C ^― , (C ₆ F ₅ SO ₂ ) ₂ N ^― , (C ₆ F ₅ SO ₂ ) ₃ C ^― , (C ₆ F ₅ OSO ₂ ) ₂ N ^― , (C ₆ F ₅ OSO ₂ ) ₃ C ^― , (C ₆ F ₅ ) ₄ B ^― and CF ₃ (CF ₂ ) ₃ SO ₃ ^― (where , n is an integer greater than or equal to 1), wherein the pressure-sensitive adhesive composition is selected from the group consisting of. 3. The method according to claim 1 or 2,
The cation of the ionic compound is pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiouronium, piperidinium, pyrazolium, methylium, lithium, A pressure-sensitive adhesive composition, characterized in that one selected from the group consisting of morpholinium. 3. The method according to claim 1 or 2,
(B) the hydroxyl group-containing copolymerizable monomer is 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) at least one selected from the group consisting of acrylamide,
(C) the copolymerizable monomer containing a carboxyl group is (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- ( Meth)acryloyloxypropylhexahydrophthalic acid, 2-(meth)acryloyloxyethylphthalic acid, 2-(meth)acryloyloxyethylsuccinic acid, 2-(meth)acryloyloxyethylmaleic acid, carboxypoly An adhesive composition, characterized in that at least one selected from the group consisting of caprolactone mono(meth)acrylate and 2-(meth)acryloyloxyethyltetrahydrophthalic acid. 3. The method according to claim 1 or 2,
The pressure-sensitive adhesive composition further comprises (E) a crosslinking retarder and (F) a crosslinking catalyst,
(E) the crosslinking retardant is a ketoenol tautomeric compound,
Based on 100 parts by weight of the acrylic polymer, the (E) crosslinking retarder is contained in a ratio of 0.1 to 300 parts by weight,
(F) the crosslinking catalyst is at least one metal chelate compound selected from the group consisting of an aluminum chelate compound, a titanium chelate compound, and an iron chelate compound,
With respect to 100 parts by weight of the acrylic polymer, the (F) crosslinking catalyst is contained in a ratio of 0.001 to 0.5 parts by weight,
The pressure-sensitive adhesive composition, characterized in that the (E) / weight part ratio of (F) is 80 to 1000. 3. The method according to claim 1 or 2,
The weight average molecular weight obtained by copolymerizing a (meth)acrylic acid ester monomer having an alkyl group having C1 to 18 carbon atoms and a polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer with respect to 100 parts by weight of the acrylic polymer in the pressure-sensitive adhesive composition is 10 More than 10,000 and 300,000 or less copolymers are contained in the ratio of 0.1-5.0 weight part, The adhesive composition characterized by the above-mentioned. An adhesive film in which a pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition according to claim 1 or 2 is laminated on one surface of a resin film. A surface protection film using the adhesive film of claim 7 . The optical film with the adhesive layer by which the adhesive layer which consists of the adhesive composition of Claim 1 or 2 is laminated|stacked on at least one surface of an optical film.