Composition for pressure-sensitive adhesives, pressure-sensitive adhesive film, and surface-protective film

Abstract

To provide a composition for pressure-sensitive adhesives allowing production of a pressure-sensitive adhesive film excellent in anti-static and low-contamination properties.SOLUTION: An embodiment relates to a composition for pressure-sensitive adhesives which contains a (meth)acrylic polymer (A), an alkali metal salt (B), and a compound (C) represented by formula (I).SELECTED DRAWING: None

Description

[Technical Field]

[0001] Embodiments of the present invention relate to adhesive compositions, adhesive films, and surface protective films. . [Background technology]

[0002] Optical films such as polarizing plates are used in displays. A protective film may be applied to the surface. The protective film may affect the optical film. The surface of the material is protected, preventing scratches and dirt from adhering during transportation and the manufacturing process of the display. This can prevent that.

[0003] To prevent the surface protective film from shifting away from the optical film, the surface protective film is generally... It comprises a base film and an adhesive film formed on one side of the base film. The visual inspection of the film is performed with the surface protective film laminated to the optical film. Because this can happen, highly transparent acrylic adhesives are widely used in adhesive films. Also, the surface protective film should be peeled off from the optical film when it is no longer needed. To be removed. When peeling off the surface protective film, it is usually designed to be easily removed. Adhesives with low tack strength are used in adhesive films.

[0004] When peeling off the surface protective film, especially at high speeds, noise is generated. This phenomenon can occur. Also, due to the peeling charge generated when peeling and removing the material... This can lead to phenomena such as dust adhering to the surface of the optical film and damage to circuit components. There are also factors such as the peeling speed of the surface protective film, which tends to increase in order to improve productivity. As the peeling speed increases, the peeling band voltage also increases, and problems caused by these phenomena occur. It will become cheaper.

[0005] Furthermore, in recent years, as displays have become higher resolution, the appearance of the optical film has become a concern. There is a growing demand for this. Therefore, surface protective films are designed to allow the optical film to be removed after peeling. The characteristic of leaving minimal adhesive residue is required.

[0006] Reference 1 describes an ionic adhesive composition used for forming a surface protective film. An adhesive composition is disclosed, characterized by containing a liquid and an acrylic polymer. Furthermore, Reference 2 describes a material having an adhesive layer formed on the surface of a base film, and the adhesive layer The acrylic adhesive that makes up the product contains at least an antistatic agent and fluorine or silicon. A surface protective film is disclosed, characterized by being externally added with a compound. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2005-330464 [Patent Document 2] Japanese Patent Publication No. 2011-63712 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] One embodiment of the present invention is for manufacturing an adhesive film that has excellent antistatic properties and low contamination properties. The objective is to provide an adhesive composition that can achieve the following. Another embodiment of the present invention is The objective is to provide an adhesive film with excellent antistatic properties and low contamination properties. Furthermore, Another embodiment of the present invention relates to a surface having an antistatic and low contamination adhesive film. An object of the present invention is to provide a protective film.

Means for Solving the Problems

[0009] The present invention includes various embodiments. Examples of the embodiments are listed below. The present invention is not limited to the following embodiments.

[0010] One embodiment relates to an adhesive composition containing a (meth)acrylic polymer (A), an alkali metal salt (B), and a compound (C) represented by the formula (I ).

Chemical Formula

[0011] In one embodiment, the adhesive composition may further contain a crosslinking agent (D).

[0012] In one embodiment, the (meth)acrylic polymer (A) preferably contains a structural unit derived from an alkyl (meth)acrylate monomer and a structural unit derived from a (meth)acrylic monomer having a hydroxyl group or a carboxyl group.

[0013] Another embodiment relates to an adhesive film obtained using the adhesive composition.

[0014] Another embodiment relates to a surface protection film having the adhesive film obtained using the adhesive composition and a base film.

Advantages of the Invention

[0015] According to one embodiment of the present invention, an adhesive film with excellent antistatic properties and low contamination properties can be manufactured. An adhesive composition that can perform this can be provided. Another embodiment of the present invention According to this, it is possible to provide an adhesive film with excellent antistatic properties and low contamination properties. Furthermore, according to another embodiment of the present invention, an adhesive film having excellent antistatic properties and low contamination properties is provided. A surface protective film can be provided. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a schematic cross-sectional view showing an example of a surface protection film, which is one embodiment of the film. [Modes for carrying out the invention]

[0017] The embodiments of the present invention will be described below. The present invention is not limited to the embodiments described below.

[0018] <Composition for adhesives> An embodiment of the present invention is an adhesive composition containing (meth)acrylic polymer (A), and an alkaline The adhesive composition contains a metal salt (B) and a compound (C) represented by formula (1). The product may further contain any components such as a crosslinking agent (D) and various additives.

[0019] As a method for imparting antistatic properties to a surface protective film, the adhesive film in contact with the substrate... One method is to add an antistatic agent. However, the inclusion of an antistatic agent in order to enhance antistatic properties... Increasing the amount of antistatic agent will also increase the amount of antistatic agent adhering to the substrate, making the substrate more susceptible to contamination. Generally, there is a trade-off between antistatic properties and low-stain properties, and it is difficult to achieve both. This tends to be difficult. In embodiments of the present invention, (meth)acrylic polymer (A) A composition for adhesives containing an alkali metal salt (B) and a compound represented by formula (1) (C). Depending on the material, it is possible to achieve both excellent antistatic properties and low-contamination properties.

[0020] [(Meth)acrylic polymer (A)] (Meth)acrylic polymer (A) has structural units derived from (meth)acrylic monomers It is a polymer containing (meth)acrylic monomers. It has an acryloyl group. In this specification, "(meth)acrylic monomer" means acrylic It is a general term for monomers and methacrylic monomers, and the "(meth)acryloyl group" is acryloyl This is a general term for yl groups and methacryloyl groups.

[0021] The structural unit derived from (meth)acrylic monomer is alkyl(meth)acrylate mono It is preferable to include at least one structural unit derived from M1. (meth)acrylic The structural unit derived from the monomer is derived from alkyl (meth)acrylate monomer (M1). It may contain two or more types of resulting structural units.

[0022] The alkyl (meth)acrylate monomer (M1) is preferably represented by the following formula (m1). It contains the monomer (hereinafter sometimes referred to as "monomer (m1)").

[0023] [ka]

[0024] In the formula, R 1a R represents a hydrogen atom or a methyl group. 1b This represents an alkyl group.

[0025] Alkyl groups may be linear, branched, or cyclic. It is preferable that it is an alkyl group. The number of carbon atoms in the alkyl group is preferably 1 to 22, and 1 It is more preferable that the number be between 16, and even more preferable that it be between 1 and 12.

[0026] Alkyl (meth)acrylate monomer (M1) is, for example, methyl (meth)acrylate Ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate (T) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, pe methyl(meth)acrylate, hexyl(meth)acrylate, heptyl(meth)acrylate Rate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethyl Isohexyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl Calcium acrylate, dodecyl acrylate, tridecyl acrylate Tetradecyl (meth)acrylate (myristyl (meth)acrylate), isomi Listyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate (T)Acrylate (Cetyl (meth)acrylate), Isocetyl (meth)acrylate, Heptadecyl (meth)acrylate, octadecyl (meth)acrylate (stearyl ( Selected from the group consisting of meth)acrylate and isostearyl(meth)acrylate It is preferable to include at least one of the following.

[0027] (Meth)acrylic polymer (A) has monomers that form structural units of alkyl(meth)acrylic polymer. If acrylate monomer (M1) is included, its content is 100% of the total amount of all monomers. Based on the amount in parts, it is preferable that it be 50 parts by mass or more, and 55 parts by mass or more. More preferably, the content is 60 parts by mass or more. In this case, good adhesion between the adhesive film and the substrate tends to be easily obtained. Alkyl ( The content of meth)acrylate monomer (M1) should be considered when using other monomers. Furthermore, it is preferable that the total amount of all monomers be 99 parts by mass or less, based on a standard of 100 parts by mass. More preferably 95 parts by mass or less, and even more preferably 90 parts by mass or less. It's nice.

[0028] Structural units derived from (meth)acrylic monomers are hydroxyl groups or carboxyl groups. It contains at least one structural unit derived from a (meth)acrylic monomer (M2) having This is preferable. (Meth)acrylic monomer (M2) has a hydroxyl group and a carboxyl group. or having at least both a hydroxyl group and a carboxyl group. (meth)acrylic The structural unit derived from the monomer is the structure derived from the (meth)acrylate monomer (M2). It may contain two or more types of units.

[0029] The (meth)acrylic monomer (M2) is preferably represented by the following formula (m2-1). A monomer (hereinafter sometimes referred to as "monomer (m2-1)") is given by the following formula (m2-2) The monomers represented (hereinafter sometimes referred to as "monomer (m2-2)"), and (meta ) Contains at least one selected from the group consisting of acrylic acids. (meth)acrylic monomer (M2) more preferably comprises monomer (m2-1).

[0030] [ka]

[0031] In the formula, R 2a R represents a hydrogen atom or a methyl group. 2b This represents a divalent linking group.

[0032] [ka]

[0033] In the formula, R 3a R represents a hydrogen atom or a methyl group. 3b This represents a divalent linking group.

[0034] In monomer (m2-1) and monomer (m2-2), the divalent linking group is For example, one or more selected from the group consisting of alkylene groups, oxy groups, and carbonyl groups. It is preferable that the group contains the alkylene group. The alkylene group may be linear, branched, or cyclic. The alkylene group is preferably a linear alkylene group. The number of carbon atoms in the alkylene group is Preferably 1 to 22, more preferably 1 to 16, and 1 to 12. This is even more preferable. The divalent linking group is more preferably an alkylene group, and a linear a It is even more preferable that the group be a lukilen group.

[0035] (Meth)acrylic monomer (M2) is, for example, 2-hydroxyethyl(meth)acrylic Rate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth) Acrylates, hydroxyalkyls such as 8-hydroxyoctyl (meth)acrylate Meth)acrylate; N-hydroxy(meth)acrylamide, N-hydroxymethyl( Hydroxyl meth)acrylamide, N-hydroxyethyl (meth)acrylamide, etc. Group-containing (meth)acrylamide; 2-carboxyethyl (meth)acrylate, 5-cal Boxypentyl (meth)acrylate, 2-(meth)acryloyloxyethylhexyl Hydrophthalic acid, 2-(meth)acryloyloxypropylhexahydrophthalic acid, 2-( 2-(meth)acryloyloxyethylphthalate, 2-(meth)acryloyloxyethyl phthalate tetrahydrophthalic acid, 2-(meth)acryloyloxypropyltetrahydrophthalic acid, 2 -(meth)acryloyloxypropylphthalate, 2-(meth)acryloyloxyethylphthalate Lusuccinic acid, 2-(meth)acryloyloxypropyl succinate, 2-(meth)acrylo Iloxyethyl maleic acid, 2-(meth)acryloyloxypropyl maleic acid, Carboxypolycaprolactone mono(meth)acrylate and other carboxyl group-containing (meth) acrylates. Includes at least one selected from the group consisting of acrylates and (meth)acrylic acid. Preferably, the (meth)acrylic monomer (M2) is, for example, a hydroxyalkyl ( At least one selected from the group consisting of meth)acrylate and (meth)acrylic acid It is more preferable to include, and even more preferable to include, hydroxyalkyl (meth)acrylate. It seems so.

[0036] (Meth)acrylic polymer (A) The monomers that form the structural units are (meth)acrylic polymer If a monomer (M2) is included, its content is based on 100 parts by mass of the total of all monomers. Preferably, the amount is 0.1 parts by mass or more, and more preferably 0.5 parts by mass or more. More preferably 2 parts by mass or more, and particularly preferably 2.5 parts by mass or more. It is desirable. When the content is 0.1 parts by mass or more, sufficient adhesiveness tends to be easily obtained. The content of (meth)acrylic monomer (M2) is based on 100 parts by mass of the total of all monomers. As a general rule, the amount is preferably 20 parts by mass or less, and more preferably 15 parts by mass or less. Furthermore, it is more preferable that it be 14 parts by mass or less, and particularly preferable that it be 12 parts by mass or less. It is easy to obtain the effect of preventing contamination of the adherend when the content is 20 parts by mass or less. There is a tendency.

[0037] The structural unit derived from (meth)acrylic monomer is alkyl(meth)acrylate mono Structural units derived from M1 and (meth)acrylate monomers (M2) The structural units are different from the structural units themselves and are derived from other (meth)acrylic monomers (M3). It may contain at least one type. Structural units derived from (meth)acrylic monomers are (meth)acrylic It may contain two or more structural units derived from kryl monomer (M3).

[0038] (Meth)acrylic monomer (M3) is, for example, (poly)alkylene glycol monoa (Meth)acrylates containing (poly)oxyalkylene groups, such as hydrate ether mono(meth)acrylate. Preferably, it contains an acrylic monomer. In this specification, "(poly)alkyleneglycan "Col" is a general term for "alkylene glycol" and "polyalkylene glycol," "(Poly)oxyalkylene" is a combination of "oxyalkylene" and "polyoxyalkylene". It is a general term.

[0039] The monomers that form the structural units of (meth)acrylic polymer (A) are (meth)acrylic polymers. If it contains monomer (M3), its content is based on 100 parts by mass of the total of all monomers. Preferably, the amount is 1 part by mass or more, and more preferably 2 parts by mass or more. It is more preferable that the content is 3 parts by mass or more. (meth)acrylic monomer (M3) It is preferable that the amount be 20 parts by mass or less, based on a total of 100 parts by mass of all monomers. More preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less. It's nice.

[0040] (Meth)acrylic polymer (A) is a structural unit derived from (meth)acrylic monomer and It may also contain other different structural units. Other structural units include, for example, vinyl acetate. Vinyl ester monomers; styrene, sodium styrene sulfonate, and other styrene-based monomers Nomers; olefin monomers such as butadiene; vinyl chloride, tetrafluoroethylene, etc. Examples of structural units derived from vinyl group-containing monomers, such as halogen-containing monomers.

[0041] (Meth)acrylic polymer (A) is a compound derived from (meth)acrylic monomer (M2). Preferably contains a building block, derived from alkyl (meth)acrylate monomer (M1). It is preferable to include structural units derived from (meth)acrylic monomer (M2) and structural units derived from (meth)acrylic monomer (M2). It is preferable.

[0042] The polymerization method for (meth)acrylic polymer (A) is not particularly limited. Polymerization methods for acrylic polymer (A) include solution polymerization, emulsion polymerization, suspension polymerization, bulk polymerization, etc. Known polymerization methods can be used.

[0043] As a polymerization initiator when polymerizing (meth)acrylic polymer (A), a heat-activated radioactive polymer is used. Compounds that produce ions can be used. Specifically, benzoyl peroxide, lauroyl Organic peroxides such as peroxides; 2,2'-azobisisobutyronitrile, 2,2'-a Examples include azo compounds such as zobis(2-methylbutyronitrile).

[0044] The glass transition temperature (Tg) of (meth)acrylic polymer (A) is 0°C or lower. Preferably, -5°C or lower, more preferably -10°C or lower. The glass transition temperature of (meth)acrylic polymer (A) is preferably -50°C or higher. It is more preferable that the temperature be above -40°C, and even more preferable that it be above -25°C. stomach.

[0045] In this specification, the glass transition temperature (Tg) of (meth)acrylic polymer (A) is defined as follows: This refers to the theoretically calculated value obtained by the FOX formula. 1 / Tg=W1 / Tg1+W2 / Tg2++Wn / Tgn (In the formula, Tg is the glass transition temperature (°C) of the (meth)acrylic polymer (A), and W1, W2, ..., Wn are the mass fractions of each monomer relative to the total mass of all monomers. Tg1, Tg2, ..., Tgn are the gals of the homopolymer of each monomer, respectively. This is the lath transition temperature. The literature value is used as the glass transition temperature of the homopolymer used in this calculation. It can be used. The glass transition temperatures of various homopolymers are, for example, those of Mitsubishi Rayon Co., Ltd. Company's acrylic ester catalog (1997 edition), and New Polymer Library 7, "For paints" This is described in "Introduction to Synthetic Resins," published by the Polymer Publishing Association and authored by Kyozo Kitaoka.

[0046] The following method is used to adjust the glass transition temperature of (meth)acrylic polymer (A): For example, by using alkyl (meth)acrylates with a large number of carbon atoms, The transition temperature can be lowered. On the other hand, alkyl(meth)acrylates with a small number of carbon atoms The glass transition temperature can be increased by using methacrylate. However, the glass transition temperature tends to be high.

[0047] The weight-average molecular weight of (meth)acrylic polymer (A) must be 50,000 or more. Preferably, 80,000 or more; more preferably, 100,000 or more. This is even more preferable. The weight-average molecular weight of (meth)acrylic polymer (A) is 800,000 Preferably it is less than or equal to 700,000, more preferably 600,0 It is even more preferable that the weight-average molecular weight is 00 or less. In this specification, the weight-average molecular weight is defined as Gelpar The conversion was performed using a calibration curve for standard polystyrene by geometrometry chromatography (GPC). This is a value obtained by calculation. Specifically, one should follow the measurement method described in the examples. When the uniform molecular weight is 50,000 or higher, an adhesive film with good adhesive strength can be obtained. There is a tendency for adhesive compositions to have high viscosity when the weight-average molecular weight is 800,000 or less. It is easier to prevent this from happening.

[0048] Even if the adhesive composition contains only one type of (meth)acrylic polymer (A), it may contain two or more types. It may also contain (meth)acrylic polymer (A).

[0049] [Alkali metal salts (B)] Alkali metal salt (B) contains an alkali metal ion and a counter anion. Adhesive composition The inclusion of an alkali metal salt (B) imparts conductivity to the adhesive film, and the adhesive film It is thought that the lumen will exhibit good antistatic properties. Alkali metal salt (B) is Potassium metal ions include lithium ions, sodium ions, and potassium ions. Preferably, it contains at least one selected from the group, lithium ion and sodium It is more preferable to include at least one selected from the group consisting of muions, lithium It is even more preferable to include ions. If lithium ions are included, better antistatic properties are obtained. It can be obtained.

[0050] Counter anions include, for example, chloride ions, perchlorate ions, hexafluorophosphate ions, Hexafluoroarsenate ion, tetrafluoroborate ion, tetraphenylborate ion , trifluoromethanesulfonate ion, bis(trifluoromethanesulfonyl)imide Select from the group consisting of ions and bis(pentafluoroethanesulfonyl)imide ions. Preferably, it includes at least one of the following:

[0051] As an example of alkali metal salt (B), the salt represented by the following formula can be cited (hereinafter, The salt represented by equation (b1) is sometimes called "salt (b1)". Equations (b2) to (b6) The same applies to salts represented by either of the two terms.

[0052] [ka]

[0053] [ka]

[0054] [ka]

[0055] [ka]

[0056] [ka]

[0057] [ka]

[0058] In each formula, M represents an alkali metal ion, and R represents a fluorine atom, alkyl group, or fluorocarbon. R represents an alkyl group, an aryl group, or a fluoroaryl group. 1 and R 2 These are each German In addition, a fluorine atom, alkyl group, fluoroalkyl group, aryl group, or fluoroalkyl group It represents the 'L' group.

[0059] The number of carbon atoms in alkyl and fluoroalkyl groups is preferably 1 to 6, and 1 to 4 It is more preferable that fluoroalkyl groups contain one of the hydrogen atoms in an alkyl group. Even if the part is a fluoroalkyl group substituted with fluorine atoms, all of the hydrogen atoms are fluorine A fluoroalkyl group (i.e., a perfluoroalkyl group) substituted with an elementary atom. It is also fine, and preferably it is a perfluoroalkyl group. Aryl group and fluoro The number of carbon atoms in the reel group is preferably 6 to 20, and more preferably 6 to 10. Fluoroaryl groups are formed when some of the hydrogen atoms in an aryl group are replaced by fluorine atoms. Even in the converted fluoroaryl group, all hydrogen atoms are replaced by fluorine atoms. It may also be a fluoroaryl group (i.e., a perfluoroaryl group), perfluoro A loaryl group is preferable.

[0060] Alkali metal salt (B) is selected from the group consisting of salts (b1) to salts (b6) at least Preferably, it also contains one type, from the group consisting of salt (b1), salt (b5), and salt (b6). It is more preferable to include at least one selected salt, consisting of salt (b1) and salt (b5). It is even more preferable to include at least one selected from the group. In particular, (meth)acrylic It has good compatibility with polymer (A), does not contain chlorine, and releases alkali metal ions. From the standpoint of cost-effectiveness, etc., it is preferable that the alkali metal salt (B) contains salt (b5).

[0061] Alkali metal salts (B) specifically include lithium chloride (LiCl) and lithium perchlorate. (LiClO4), lithium hexafluorophosphate (LiPF6), hexafluoroarsenic acid Lithium (LiAsF6), lithium tetrafluoroborate (LiBF4), tetrafluoroborate Lithium nylborate (LiB(C6H5)4), lithium trifluoromethanesulfonate (LiCF3SO3), bis(trifluoromethanesulfonyl)imide lithium (LiN (CF3SO2)2), bis(pentafluoroethanesulfonyl)imidolithium (Li Lithium salts such as N(C2F5SO2)2); sodium chloride (NaCl), sodium perchlorate Sodium phosphate (NaClO4), sodium hexafluorophosphate (NaPF6), hexafluorophosphate Sodium oroar (NaAsF6), sodium tetrafluoroborate (NaBF4) Sodium tetraphenylborate (NaB(C6H5)4), trifluoromethanesulfate Sodium phosphate (NaCF3SO3), bis(trifluoromethanesulfonyl)imide Sodium (NaN(CF3SO2)2), bis(pentafluoroethanesulfonyl) Sodium salts such as sodium mid (NaN(C2F5SO2)2); and potassium chloride (KCl), potassium perchlorate (KClO4), potassium hexafluorophosphate (KPF) 6) Potassium hexafluoroarsenate (KAsF6), potassium tetrafluoroborate (K BF4), potassium tetraphenylborate (KB(C6H5)4), trifluoromethane Potassium sulfonate (KCF3SO3), bis(trifluoromethanesulfonyl)imide Potassium (KN(CF3SO2)2), bis(pentafluoroethanesulfonyl)imide Selected from the group consisting of potassium salts such as potassium (KN(C2F5SO2)2) It is preferable that each contains at least one type.

[0062] Alkali metal salts (B) have a melting point above 25°C and are solid salts at room temperature (e.g., 25°C). It is preferable that the salt, which is solid at room temperature, does not easily leak out of the adhesive film. This is preferable from the viewpoint of preventing contamination of the adherend by the film.

[0063] Even if the adhesive composition contains only one alkali metal salt (B), it may contain two or more alkalis. It may contain a metal salt (B). The amount of alkali metal salt (B) is (meth)acrylic. It is preferable that the amount be 0.1 parts by mass or more, based on 100 parts by mass of rimer (A), It is more preferably 0.2 parts by mass or more, and even more preferably 0.5 parts by mass or more. When the amount is 0.1 parts by mass or more, better antistatic properties can be obtained. The content of group salt (B) is based on 100 parts by mass of (meth)acrylic polymer (A), It is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and still more preferably 5 parts by mass or less. When it is 10 parts by mass or less, better low contamination properties can be obtained. [[ID=​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​n H m F 2n+1-m (n is an integer greater than or equal to 1, and m is an integer greater than or equal to 0.) However, m is an integer less than or equal to 2n. It is preferable that the base is represented by ). The value is 1 to 12, more preferably 1 to 8, and even more preferably 1 to 4. m is preferably 0 to 2n, more preferably 0 to n, and even more preferably 0. ru.

[0069] In formula (I), R is independently a hydrogen atom and an alkyl group having 1 to 12 carbon atoms. Compounds that are a group or a fluoroalkyl group having 1 to 12 carbon atoms reduce contamination of adhesive films. This is a preferred compound from the viewpoint of improving dyeability.

[0070] Examples of compound (C) include cyclic carbonate compounds and cyclic urea compounds. The substance (C) specifically consists of ethylene carbonate, propylene carbonate, and 1,2- Tylene carbonate, trans-2,3-butylene carbonate, cis-2,3-butylene 1,2-Pentylene carbonate, trans-2,3-Pentylene carbonate Ponate, cis-2,3-pentylene carbonate, fluoroethylene carbonate, Lifluoromethylethylene carbonate, 4,5-difluoroethylene carbonate, etc. A group consisting of cyclic carbonate compounds and cyclic urea compounds such as 2-imidazolidinone. Preferably, it contains at least one selected from the above. The cyclic carbonate compound is of formula (I It is a compound represented by formula (I), where two X atoms are oxygen atoms. A cyclic urea compound is represented by formula (I). It is a compound in which two X atoms are nitrogen atoms. Compound (C) is a cyclic carbonate compound. Preferably contains substances, and the group consists of ethylene carbonate and propylene carbonate. It is more preferable to include at least one selected from the following. From the viewpoint of conductivity, the compound ( C) preferably contains at least ethylene carbonate.

[0071] From the perspective of achieving both antistatic properties and low contamination properties, compound (C) is a compound with a melting point above 25°C. It is preferable that it be a compound. Compounds with a melting point above 25°C will not leak out of the adhesive film. Therefore, it is preferable from the viewpoint of preventing contamination of the adherend by the adhesive film.

[0072] The adhesive composition may contain only one compound (C), or it may contain two or more compounds (C). It may contain. The content of compound (C) is 100% by mass of (meth)acrylic polymer (A). Based on parts, it is preferable to have 0.2 parts by mass or more, and 0.5 parts by mass or more. More preferably, and even more preferably 1 part by mass or more. This allows for better antistatic properties. The content of compound (C) is (meth)acrylic. It is preferable that the amount be 15 parts by mass or less, based on 100 parts by mass of polymer (A). It is more preferable that the amount be 10 parts by mass or less, and even more preferable that it be 8 parts by mass or less. When the amount is 5 parts by mass or less, better low contamination properties can be obtained.

[0073] [Crosslinking agent (D)] The adhesive composition may contain a crosslinking agent (D). The crosslinking agent (D) may be, for example, isopropyl alcohol. Anate compounds, epoxy compounds, (meth)acrylate compounds, and metal chelate compounds Preferably, it contains at least one selected from the group consisting of substances. Crosslinking reaction by heating. Since this can be advanced, the crosslinking agent (D) is, for example, an isocyanate compound and It is more preferable to include at least one selected from the group consisting of oxy compounds, It is even more preferable to include a cyanate compound.

[0074] The isocyanate compound can be any isocyanate compound with two or more functions. The nate compounds are preferably bifunctional isocyanate compounds and trifunctional or more isocyanate compounds. It includes at least one selected from the group consisting of isocyanate compounds. The isocyanate compound is Even if it contains only a bifunctional isocyanate compound, or a trifunctional or more functional isocyanate compound It may contain only the following: Isocyanate compounds include difunctional isocyanate compounds and trifunctional compounds. The above-mentioned isocyanate compounds may also be included.

[0075] A bifunctional isocyanate compound has two isocyanate (-NCO) groups in one molecule. One or more compounds selected from the following are acceptable. (Bifunctional isocyanate compound) For example, aliphatic diisocyanates; aromatic diisocyanates; aliphatic di At least one adduct selected from socianates and aromatic diisocyanates. ; at least one selected from aliphatic diisocyanates and aromatic diisocyanates Examples include allophanates of various species. "Aliphatic diisocyanates and aromatic diisocyanates" "At least one adduct selected from cyanates" is, for example, an aliphatic diisocyanate. At least one selected from annetes and aromatic diisocyanates and a bifunctional polio It is an adduct of a hydroxyl group. A difunctional polyol has two hydroxyl groups in one molecule. It is a compound having an OH group. As a difunctional polyol, ethylene glycol, pro Examples include pyrene glycol.

[0076] A specific example of aliphatic diisocyanates is hexamethylene diisocyanate. HDI), isophorone diisocyanate (IPDI), trimethylhexamethylenediiso Examples include cyanates (TMDI) and hydrogenated xylylene diisocyanate (H6XDI). Specifically, aromatic diisocyanates include diphenylmethane diisocyanates. (MDI), xylylene diisocyanate (XDI), dimethyl diphenyl diisocyanate Examples include anate (TOID) and tolylene diisocyanate (TDI).

[0077] Isocyanate compounds with three or more functional groups have three or more isocyanate groups in one molecule. It may be one or more compounds selected from the compounds, and each molecule may contain three isocyanates. It is preferable that the compound be one or more selected from compounds having a trifunctional group. For example, an adduct of a bifunctional isocyanate compound; 2 Isocyanurates of functional isocyanate compounds; biuretic compounds of difunctional isocyanate compounds Examples include difunctional isocyanate compounds. "Adduct compounds of difunctional isocyanate compounds" are, for example, difunctional isocyanate compounds. It is an adduct compound of a polyol with three or more functions. Polyols are compounds that have three or more hydroxyl (-OH) groups in a single molecule. Examples of polyols with three or more functionalities include trimethylolpropane (TMP) and glycerin. It can be done.

[0078] As an example of an isocyanate compound, we can cite the isocyanate compound represented by the following formula. This can be formed (hereinafter, the salt represented by formula (d1) will be called "isocyanate compound (d1)"). There are cases where this applies to isocyanate compounds represented by any of the formulas (d2) to (d6). The same applies to this as well.

[0079] [ka]

[0080] [ka]

[0081] [ka]

[0082] [ka]

[0083] [ka]

[0084] [ka]

[0085] In each formula, R independently represents a divalent organic group, 1 This represents a monovalent substituent, R 2 represents a divalent organic group, R 3 This represents a trivalent organic group.

[0086] R is preferably a substituted or unsubstituted hydrocarbon group, and is a linear or branched aliphatic group. Hydrocarbon group; alicyclic hydrocarbon group; or, more preferably, aromatic hydrocarbon group. Alphatic hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups may be substituted or unsubstituted. Good. The aliphatic hydrocarbon group is preferably an alkyl group. The number is preferably between 1 and 22, more preferably between 1 and 12, and between 1 and 8. It is even more preferable that the alicyclic hydrocarbon group be a cycloalkyl group. The number of carbon atoms in the alicyclic hydrocarbon group is preferably 3 to 12, and more preferably 5 to 8. Preferably, it is 6, and more preferably, the number of carbon atoms in the aromatic hydrocarbon group is 6 to 20. It is preferable that the value be 6 to 10, and even more preferable that it be 6. Aromatic hydrocarbon groups are derived from linear or branched aliphatic hydrocarbon groups and alicyclic hydrocarbon groups. It may have at least one substituent selected from the group.

[0087] Examples of R include hydrocarbon groups such as methylene group, ethylene group, propylene group, and trimene group. ethylene group, methylethylene group, tetramethylene group, 1-methyltrimethylene group, 2-methyl Trimethylene group, pentamethylene group, 1-methyltetramethylene group, 2-methyltetramethylene group Methylene group, hexamethylene group, 1-methylpentylene group, 2-methylpentylene group, 3 -Methylpentylene group, 1-ethyltetramethylene group, 2-ethyltetramethylene group, Linear or branched aliphatic hydrocarbon groups such as butamethylene groups and octamethylene groups; cyclop Alicyclic hydrocarbon groups such as thyl groups, cyclohexyl groups, and cycloheptyl groups; phenylene groups, Examples include aromatic hydrocarbon groups such as triylene groups, xylylene groups, and naphthylene groups.

[0088] R1 This may be a substituent containing a hydroxyl group. 2 This involves substituted or unsubstituted carbonization. It is preferably a hydrogen group, and preferably a substituted or unsubstituted alkylene group. 3 It is preferably a substituted or unsubstituted hydrocarbon group, and a substituted or unsubstituted alkane- It is preferable that it be a triyl group. If the hydrocarbon group has substituents, the substituents are A droxyl group is one example.

[0089] The isocyanate compound is selected from the group consisting of isocyanate compounds (d1) to (d6). Preferably, it contains at least one selected isocyanate compound (d2) to (d6) It is more preferable to include at least one selected from the group consisting of ). In particular, a good band From the viewpoint of obtaining antistatic properties and adhesion, isocyanate compounds are isocyanate compounds ( It is preferable that it includes at least one selected from the group consisting of d3) and (d4), i It is more preferable to include a socionate compound (d3).

[0090] If the adhesive composition contains a crosslinking agent (D), the amount of crosslinking agent (D) is such that the acrylic polymer It is preferable that the amount be 0.1 parts by mass or more, based on 100 parts by mass of rimer (A), It is more preferably 0.5 parts by mass or more, and even more preferably 1 part by mass or more. The amount of crosslinking agent (D) is 20 parts by mass, based on 100 parts by mass of acrylic polymer (A). It is preferably 15 parts by mass or less, more preferably 10 parts by mass or less. It is even more preferable that the following is the case. The adhesive composition contains one crosslinking agent (D) alone. Furthermore, two or more types may be included in combination.

[0091] The adhesive composition may contain a curing accelerator. The curing accelerator is preferably (meth ) Accelerates the reaction rate between the functional groups contained in the acrylic polymer and the functional groups contained in the curing agent (D). This is what causes it. Here, functional groups are (meth)acryloyl group, hydroxyl group, and This refers to groups such as ruboxyl groups, epoxy groups, and isocyanate groups.

[0092] For example, organometallic compounds, tertiary amine compounds, etc., can be used as curing accelerators. Yes. Specifically, as organometallic compounds, dibutyltin dilaurate, dibutyltin dichloro Examples of tin-based catalysts include dibutyltin oxide and other tin-based catalysts.

[0093] The adhesive composition may contain a solvent. The solvent is preferably an organic solvent. Examples of solvents include formic acid, acetic acid, methanol, ethanol, propanol, and methyl ethanol. Rosolve, Cellosolve, Acetone, Acetylacetone, Acetonitrile, Hexane, Ben Zene, toluene, dichloromethane, ethyl acetate, butyl acetate, chlorobenzene, dichloro Examples include benzene.

[0094] [Other optional components] The adhesive composition may contain other optional components. These other optional components may include surfactants. Examples include plasticizers, fillers, curing retarders, processing aids, anti-aging agents, antioxidants, etc. The adhesive composition may contain other optional components individually or in combination of two or more. That's fine.

[0095] <Adhesive film> An adhesive film according to an embodiment of the present invention is a film obtained using the adhesive composition described above. In adhesive films, the (meth)acrylic polymer (A) is crosslinked. The method for manufacturing the adhesive film is not particularly limited and any known manufacturing method is acceptable. For example, the support film forms a layer of adhesive composition on its surface, and the layer of adhesive composition It can be obtained by drying and / or curing it. Alternatively, the adhesive film is, for example, For example, it can be formed by the extrusion method. Adhesive film formed on a support film. The material may be used after peeling it off the support film, or it may be used without peeling it off the support film. It may also be used in the form of a laminate having an adhesive film and a support film.

[0096] Methods for forming a layer of adhesive composition include known coating methods, known printing methods, etc. It is possible. For example, cast coating, spray coating, spin coating, de Tip coating, bar coating, comma coating, blade coating, Coating methods such as die coating; intaglio printing such as gravure printing, stencil printing such as screen printing. Examples include printing methods such as ink.

[0097] The drying and curing of the adhesive composition layer can be carried out by heating. The heating temperature is: For example, the temperature can be between 50 and 150°C. The heating time can be, for example, between 1 minute and 10 hours.

[0098] The thickness of the adhesive film is not particularly limited. For example, the thickness of the adhesive film may be 1 μm or more. It is preferable that it be 3 μm or larger, more preferably 3 μm or larger, and 5 μm or larger. Even more preferable is when the thickness of the adhesive film is 1 μm or more, sufficient strength can be maintained. It tends to easily provide good adhesion. The thickness of the adhesive film is, for example, 20 μm. Preferably, it is less than or equal to 18 μm, more preferably 15 μm or less. It is even more preferable that the thickness be 20 μm or less, so that sufficient flexibility can be maintained and adhesion can be maintained. The film becomes more conformable to the shape of the substrate, and the adhesive film is less likely to peel off the substrate. It tends to be easier to prevent.

[0099] The surface resistivity of the adhesive film is 1.0 × 10⁻⁶. 12 It is preferable that Ω / □ is less than or equal to 5 .0 × 10 11 It is more preferable that the value is Ω / □ or less, and 2.5 × 10 11 Ω / □ or less It is even more preferable to do this. 1.0 × 10 12 If Ω / □ is less than or equal to the substrate, the adhesive film is applied to the substrate. When peeling from the material, the generation of static electricity due to static charge can be effectively suppressed. As a result, The peel voltage caused by static electricity when peeling adhesive film from the substrate is reduced. This can suppress the effect on the adherend. If the delamination voltage is high, dust will adhere to the adherend. This phenomenon can cause malfunctions such as the destruction of circuit components located near the adherend. It can happen.

[0100] In the following evaluation, it is preferable that the adhesive film does not leave any adhesive residue on the substrate. Adhesion of the adhesive can cause defects in the appearance of the object to be coated. The adhesive film is attached to the substrate and subjected to high temperature and high humidity conditions of 85°C and 85%RH (RH: relative humidity). Leave the item undisturbed for a specified period of time. Then, peel off the adhesive film from the object to be attached to the object. Visually check for any adhesive residue. The "specified time" is 3 days, 20 days, or It can be set to 40 days.

[0101] <Surface protective film> The surface protective film according to an embodiment of the present invention is obtained using the adhesive composition described above. It has an adhesive film and a base film. The surface protective film is a cover film or other It may have any film. An example of a surface protective film is a base film and a base film A surface protective film having an adhesive film provided on one side of the film; base material film A film, an adhesive film provided on one side of the base film, and the base film of the adhesive film Examples include surface protection films having a cover film provided on the opposite side of the film. It is possible.

[0102] Figure 1 is a schematic cross-sectional view showing an example of a surface protection film. In Figure 1, the surface protection film 1 comprises a base film 4 and an adhesive film 3 provided on one surface of the base film 4. The adhesive film 3 has a cover film 2 provided on the side opposite to the base film 4. do.

[0103] The base film preferably has a plastic film. A strip provided on at least one surface of a plastic film and a plastic film. The base film may have any layer such as an antistatic layer, an antifouling layer, or an adhesion-enhancing layer. If a layer and / or an anti-fouling layer is present, the antistatic layer and / or anti-fouling layer is an adhesive layer of the base film. It is preferable that it is provided on the surface opposite to the film. The base film is any layer Having only one type is acceptable, or you may have a combination of two or more types.

[0104] At least one side of the plastic film is treated with an antistatic, anti-fouling, and adhesive coating. Surface treatments such as pre-treatment, corona treatment, and plasma treatment may be applied. Antistatic treatment and Examples include applying or incorporating an antistatic agent. The base film is treated with an antistatic agent. / or if an antifouling treatment has been applied, the antistatic treatment and / or antifouling treatment are applied to the base film. It is preferable that the adhesive film is applied to the side opposite to the adhesive film. The base film has a surface The treatment may be applied by one type only, or by a combination of two or more types.

[0105] For the antistatic layer and antistatic treatment, known antistatic agents can be used. Antifouling layer For antifouling treatment, known release agents such as silicone-based release agents and fluorine-based release agents; silica fine particles. Known antifouling agents such as the following can be used.

[0106] The plastic film is preferably a polyester film. The film can be made from, for example, polyethylene terephthalate (PET) or triacetylcellulose. (TAC), polyethylene naphthalate (PEN), polymethyl methacrylate (PMM) A) Polycarbonate (PC), polyimide (PI), polyethylene (PE), polyp Polypropylene (PP), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), cyanoacrylate Cycloolefin copolymer (COC), cycloolefin polymer (COP), containing norbolol Selected from the group consisting of resin, polyethersulfone, cellophane, and aromatic polyamide. It is preferable that the film contains at least one of the selected types.

[0107] The thickness of the base film is not particularly limited. For example, the thickness of the base film may be 10 μm or less. Preferably it is above, more preferably 30 μm or more, and 50 μm or more. It is even more preferable that the thickness of the base film is 10 μm or more, and that sufficient strength is maintained. This allows for good film winding and processability, which tends to be easily achieved. The thickness of the material is preferably 200 μm or less, and 150 μm or less. It is more preferable that it is 100 μm or less. This allows the surface protective film to maintain sufficient flexibility and easily conform to the shape of the adherend. This tends to prevent the surface protective film from peeling off the substrate.

[0108] The cover film preferably has a plastic film. , plastic film and provided on the adhesive film side surface of the plastic film It is preferable to have a release layer. Alternatively, on the adhesive film side of the plastic film, It is preferable that a release treatment is applied. For the release layer and release treatment, a silicone-based release treatment is preferred. Known release agents such as mold agents and fluorine-based release agents can be used.

[0109] For example, in the description of the base film, the plastic film is a plastic film The material includes at least one selected from the group consisting of polymers and resins, as given as examples of the material. It is preferable that it be a film, and more preferably a polyester film.

[0110] The thickness of the cover film is not particularly limited. For example, the thickness of the cover film may be 10μ It is preferable that it is m or larger, more preferably 30 μm or larger, and 50 μm or larger. It is even more preferable that the thickness of the cover film be, for example, 200 μm or less. Preferably, it is 150 μm or less, more preferably 100 μm or less. It is preferable.

[0111] The method for manufacturing the plastic film is not particularly limited and may be a known method. The release film can be obtained, for example, by forming an adhesive film on one surface of a base film. Specifically, the surface protection film can be obtained by forming a layer of a composition for an adhesive on one surface of a base film and drying and / or curing the layer of the composition for an adhesive. Or, the surface protection film can be formed, for example, by a coextrusion method. As a method for forming the adhesive film, the production methods of the adhesive film described in the description of the adhesive film can be used. In the production method of the adhesive film, a base film may be used instead of the support film.

[0112] The object to be protected by the surface protection film is not particularly limited. The surface protection film can be used by being attached so that the surface on the adhesive film side contacts the object to be protected. When the surface protection film has a cover film, the surface protection film may be attached to the object to be protected after peeling off the cover film. Examples of the object to be protected include optical members such as polarizing plates, liquid crystal display devices (LCDs), plasma display panels (PDPs), cathode ray tubes (CRTs), field emission displays (FEDs), organic EL displays, 3D displays, electronic papers, and other display devices, automotive parts, home appliance parts, mobile terminals, electronic components, building materials, and the like.

[0113]

Example

[0114] Hereinafter, embodiments of the present invention will be described by way of examples, but the present invention is not limited to these examples.

[0115] <Production of Composition for Adhesive> [Example A1] A reaction apparatus equipped with a stirrer, thermometer, reflux condenser and nitrogen inlet tube is used to add 2-ethylhexyl 90 parts by mass of acrylate, 10 parts by mass of 2-hydroxyethyl acrylate, and vinegar as a solvent. Add 50 parts by mass of ethyl acid and 0.1 parts by mass of azobisisobutyronitrile as a polymerization initiator. Next, nitrogen gas was introduced, and the air in the reaction system was replaced with nitrogen gas over a period of one hour. Then, the reaction was carried out at 75°C for 7 hours to obtain a (meth)acrylic polymer with a weight-average molecular weight of 500,000. Solution A-1) was obtained.

[0116] Solution of the obtained (meth)acrylic polymer (A-1) ((meth)acrylic polymer (A -1) Contains 100 parts by mass. ) Lithium trifluoromethanesulfonate 1 Parts by mass of the mixture and 3 parts by mass of ethylene carbonate were added and stirred. Then, duranate A was added. E700-100 (Allophanate variant of hexamethylene diisocyanate compound) 6.0 parts by mass, 5.0 parts by mass of acetylacetone, and 0.005 parts by mass of dibutyltin dilaurate After stirring and mixing, ethyl acetate and butyl acetate (mass ratio 1:1) are added to adjust the concentration. Thus, the adhesive composition of Example A1 (non-volatile content concentration 20% by mass) was obtained.

[0117] The weight-average molecular weight of (meth)acrylic polymers is determined by gel permeation chromatography. This value was obtained by measuring using the GPC method and converting it using the standard polystyrene calibration curve. The measurement conditions for the GPC method are as follows:

[0118] Equipment: HLC-8320GPC manufactured by Tosoh Corporation (with built-in radioisotope detector) Detector: RI (Differential Refractometer) Solvent: Pure primary THF (tetrahydrofuran) Guard column: TSK-guard column Super MP(HZ)-H (1 piece) Guard column size: 4.6 mm (ID) × 20 mm Column: TSK-GEL Super Multipore H manufactured by Tosoh Corporation Z-H (connected in 3) Column size: 4.6 mm (ID) × 150 mm Temperature: 40 °C Sample concentration: 0.01 g / 5 mL Injection volume: 10 μL Flow rate: 0.35 mL / min

[0119] (The glass transition temperature (Tg) of the (meth)acrylic polymer was determined by the above-mentioned FOX equation.) (As the glass transition temperature of the homopolymer, the value described in the above-mentioned "Introduction to Synthetic Resins for Paints" was used.) (It was.)

[0120] [Examples A2 to 10 and Comparative Examples A1 to 7] Acrylic polymers (A-2) to (A-4) solutions were obtained in the same manner as in Example A1 except that the monomers described in Table 1 were used.) (Next, adhesive compositions of Examples A2 to A10 and Comparative Examples A1 to A7 were obtained in the same manner as in Example A1 except that the components described in Tables 2 and 3 were used.) (The acrylic polymer (A-5) is "SK Dain (registered trademark) 1499 M" manufactured by Soken Chemical & Engineering Co., Ltd. Tables 1 to 3 show the amounts (parts by mass) of the solid components of each component.) (The acrylic polymer (A-5) is "SK Dain (registered trademark) 1499 M" manufactured by Soken Chemical & Engineering Co., Ltd. Tables 1 to 3 show the amounts (parts by mass) of the solid components of each component.) (The acrylic polymer (A-5) is "SK Dain (registered trademark) 1499 M" manufactured by Soken Chemical & Engineering Co., Ltd. Tables 1 to 3 show the amounts (parts by mass) of the solid components of each component.)

[0121]

Table 1

[0122]

Table 2

[0123] )]]

Table 3

[0124] Table 4 provides an explanation of the abbreviations used in Tables 1-3.

[0125] [Table 4]

[0126] (B-1) and (B-2) are alkali gold compounds with a melting point above 25°C and solid at 25°C. It is a group salt. (b-1) is an alkaline earth metal with a melting point above 25°C and is solid at 25°C. It is a genus salt.

[0127] (C-1) is compound (C) represented by formula (I), having a melting point of 36°C, and temperature It is a compound that is solid at 25°C. (C-2) is compound (C) represented by formula (I). It is a compound with a melting point of -55°C and is liquid at a temperature of 25°C.

[0128] (c-1) to (c-3) are polyalkylene glycols, and (c-1) and (c-2 (c-3) is a polyalkylene compound that is liquid at 25°C. It is a compound that is solid at a temperature of 25°C.

[0129] <Preparation of surface protective film> [Example B1] The adhesive composition of Example A1 is applied to a polyethylene terephthalate (PET) film. It is applied to a surface, heated at 110°C for 2 minutes, and dried and cured to a thickness of 10 μm. An adhesive film was formed. Subsequently, a silicone resin-coated polyethylene film was formed. A phthalate (PET) film is laminated onto an adhesive film to obtain a laminated film. The laminated film was aged at 40°C for 3 days, and the "PET film (base film) / It has an adhesive film / silicone resin coated PET film (cover film). A surface protective film for Example B1 was obtained.

[0130] [Examples B2-B10 and Comparative Examples B1-B7] Adhesive compositions for Examples A2-A10 and Comparative Examples A1-A7 were prepared in the same manner as in Example B1. Using this method, surface protective films for Examples B2-B10 and Comparative Examples B1-B7 were obtained.

[0131] <Test Methods and Evaluation> Regarding the surface protection films of Examples B1 to B10 and Comparative Examples B1 to B7, the adhesive film The surface resistivity, tackiness, and stain resistance were evaluated. The evaluation results are shown in Tables 5 and 6.

[0132] <Surface resistivity> The evaluation was conducted under conditions of 23°C and 50% RH humidity. Remove the film and use a resistivity meter (Mitsubishi Electric Corporation "Hiresta-UX MCP-HT"). The surface resistivity (Ω / □) of the adhesive film was measured using an 800 high resistivity meter. See Table 5. In the sixth year, "aE+b" is "a×10 b This represents ".

[0133] <Adhesive strength> The surface protective film was cut to obtain an evaluation film measuring 25 mm in width and 150 mm in length. Peel the cover film from the protective film, and the side with the adhesive film is the surface of the degreased glass plate. The evaluation film was attached to a glass plate so that it was in contact with the surface, and this was used as the measurement sample. Measurement sample From there, the evaluation film was subjected to a tensile testing machine (Shimadzu Corporation's "Autograph AG- Using "X / R", at room temperature (25°C), in a 180° direction, and with a peeling speed of 300 mm / min, strips were applied. The samples were peeled off and the peel strength was measured. The obtained peel strength was defined as the adhesive strength (N / 25mm). .

[0134] <Low contamination> A polarizing plate having an adhesive layer on one side (Sumitomo Chemical Co., Ltd.'s "Sumikaran®") Using a roller, the side of the polarizing plate with the adhesive layer is placed on the glass plate so that it is in contact with the surface of the glass plate. They were bonded together. Then, the surface protective film was applied to the polarizing plate, and the adhesive film was applied to the surface of the polarizing plate. The layers were bonded together using a roller to obtain a laminate. The laminate was then heated to 85°C and 85% RH. After being stored in the following environment for a period of 1 day, 3 days, 20 days, or 40 days, The protective film was removed. The surface contamination status of the polarizing plate after removal was visually observed.

[0135] The evaluation criteria are as follows: "Contamination present" means the surface of the polarizing plate turns white and appears dirty at a glance. It refers to a state where it is visibly contaminated, while "slightly contaminated" means that it appears contaminated at first glance. Although it may not appear as if there are any bubbles, this refers to a condition where the edges of the polarizing plate or the area near air bubbles appear white. If "no contamination" is found after both 20-day and 40-day storage, you will receive 5 points. "No contamination" after 20 days of storage, but "slight contamination" after 40 days of storage. Case 4 points In cases where there is "no contamination" after 3 days of storage, but "slight contamination" after 20 days of storage. total 3 points If "contamination is detected" after 20 days of storage, 2 points will be awarded. If "contamination is detected" after 3 days of storage, 1 point will be awarded.

[0136] [Table 5]

[0137] [Table 6]

[0138] The surface protective films in Examples B1 to B10 all have a surface resistivity of 1.0 × 10⁻⁶. 12 Ω / □ The following was observed, and it exhibited excellent antistatic properties. In particular, the surface protective film of Examples B1 and B2 The material provides excellent adhesion to the substrate, as well as high antistatic properties and high stain resistance. I was able to do both.

[0139] The surface protective films of Comparative Examples B1 to B3 are adhesive films with an alkali metal salt (B) or formula Because it does not contain compound (C) represented by (I), it does not exhibit excellent antistatic properties. Furthermore, the surface protective films of comparative examples B4, B6, and B7 exhibited inferior stain resistance. One of the causes is that alkali metal salts (B) and compounds represented by formula (I) (C) are replaced The alkylene glycol used caused minute cohesive failures in the adhesive film. It is presumed that there is. Also, in Comparative Example B5, calcium carbonate does not dissolve in the adhesive composition. Because of this, it was not possible to manufacture the adhesive film.

[0140] An adhesive film formed using an adhesive composition according to an embodiment of the present invention has excellent adhesive properties. A surface protection film with an adhesive film exhibits optical properties, antistatic properties, and low contamination properties. It was suitable for protecting components and other parts. [Explanation of symbols]

[0141] 1. Surface protective film 2 Cover film 3 Adhesive film 4. Base film

Claims

1. The composition contains a (meth)acrylic polymer (A), an alkali metal salt (B), and a compound (C) represented by formula (I), The pressure-sensitive adhesive composition, wherein the compound (C) comprises a compound having a melting point of more than 25°C. 【Chemical 1】 (In the formula, each X independently represents an oxygen atom or a nitrogen atom, and each R independently represents a hydrogen atom, an alkyl group, or a fluoroalkyl group.)

2. The pressure-sensitive adhesive composition according to claim 1 , further comprising a crosslinking agent (D).

3. 3. The pressure-sensitive adhesive composition according to claim 1, wherein the (meth)acrylic polymer (A) comprises a structural unit derived from an alkyl(meth)acrylate monomer and a structural unit derived from a (meth)acrylic monomer having a hydroxyl group or a carboxyl group.

4. A pressure-sensitive adhesive film obtained by using the pressure-sensitive adhesive composition according to any one of claims 1 to 3.

5. A surface protection film comprising a pressure-sensitive adhesive film obtained using the pressure-sensitive adhesive composition according to any one of claims 1 to 3 and a substrate film.

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