TW202028403A - Adhesive composition for protective film of optical member and protective film of optical member - Google Patents

Abstract

An adhesive composition for a protective film of an optical member, comprising: a (meth)acrylic copolymer (A) that contains a structural unit derived from n-butyl acrylate and a structural unit derived from a monomer having a hydroxyl group, that has a glass transition temperature of -40°C or lower, and that has a weight average molecular weight of from 200,000 to 2,000,000; a (meth)acrylic copolymer (B) that contains a structural unit derived from n-butyl methacrylate and a structural unit derived from a monomer having a hydroxyl group, that has a glass transition temperature of from 0°C to 45°C, and that has a weight average molecular weight of from 10,000 to 200,000; and an isocyanate crosslinking agent, wherein a content of the (meth)acrylic copolymer (B) is from 1 part by mass to 70 parts by mass with respect to 100 parts by mass of the (meth)acrylic copolymer (A), and a protective film of an optical member are provided.

Description

Adhesive composition for optical member protective film and optical member protective film

The present invention relates to an adhesive composition for an optical member protective film and an optical member protective film.

In order to protect the surface of various articles, protective films with adhesive layers are widely used. In particular, various optical components represented by polarizing plates often use protective films.

For example, Japanese Patent Laid-Open No. 2005-146151 discloses a pressure-sensitive adhesive for protective sheets, which is formed by crosslinking a crosslinkable composition so that the gel fraction becomes 80% or more. The composition contains: (A) a (meth)acrylic polymer with a glass transition temperature of -40°C or less, which is copolymerized at least from an alkyl (meth)acrylate and a monomer containing a functional group, and (B) A (meth)acrylic polymer with a glass transition temperature of 80°C or higher and (C) a crosslinking agent with alkyl (meth)acrylate as the main component; the above (B) is relative to the above (A) 100 weight Parts, blended 5-20 parts by weight. In addition, Japanese Patent Application Laid-Open No. 2013-216769 discloses an adhesive composition containing: 100 parts by mass of polymer (A) having a glass transition temperature of less than 0°C, a weight average molecular weight of 1,000 or more and less than 50,000, and a glass transition temperature It is an organopolysiloxane compound (C) having a specific structure of a polyoxyalkylene chain and a (meth)acrylic polymer (B) of 30 to 300°C. In addition, Japanese Patent Application Publication No. 2017-128636 discloses an adhesive composition containing a (meth)acrylic polymer having a hydroxyl group and an acid value of 0 mgKOH/g or more and less than 16 mgKOH/g, and an acid value of 0.1 mgKOH /g or more and 40mgKOH/g or more (meth)acrylic oligomers containing alkylene oxide chains, polyether modified polysiloxanes with reactive groups, crosslinking agents, and ionic compounds .

[The problem to be solved by the invention]

The adhesive composition used in the protective film of the optical member (hereinafter also referred to as the "adhesive composition for the optical member protective film") requires the formation of an adhesive layer, which is to attach the protective film to the surface of the optical member Later, during the period in which protection is required, functional failures such as peeling and offset from the optical member are unlikely to occur, and at the stage where protection is not required, it can be effectively peeled from the optical member. Here, the adhesive layer that is not prone to peeling off and shifting from the optical member can be evaluated by the adhesive force measured when the protective film is peeled from the optical member at a low speed (0.3m/min) (so-called low-speed peeling force) . In addition, the adhesive layer that can be effectively peeled from the optical member can be evaluated by the adhesive force (so-called high-speed peeling force) measured when the protective film is peeled from the optical member at a high speed (30 m/min).

In addition, when the protective film is peeled off from the optical member, a phenomenon called zipping (hereinafter also referred to as a "zipping phenomenon") may occur without being able to peel off smoothly and making a sound. If the zipper phenomenon occurs, streak-shaped defects may be observed on the surface of the optical member after the protective film is peeled off. Therefore, the adhesive composition for optical member protective films is also required to form an adhesive layer capable of suppressing the zipper phenomenon.

In addition, the adhesive composition for an optical member protective film is required to form an adhesive layer with high transparency so that the appearance of the optical member can be confirmed with the protective film attached.

However, when it is desired to control the low-speed peeling force and the high-speed peeling force of the adhesive layer of the protective film, since both exhibit the same behavior, it is difficult to adjust the balance between the low-speed peeling force and the high-speed peeling force. In addition, in recent years, considering the viewpoint of improving workability, there is a tendency to increase the peeling speed of the protective film from the optical member. In addition, with the thinning of optical components, there is a tendency that surface defects of the optical components caused by the zipper phenomenon when the protective film is peeled off are more likely to occur. The zipper phenomenon is thought to be caused by the strength of the adhesive layer. Generally, the adhesive force of the adhesive layer shows a tendency that the faster the peeling speed, the higher the adhesive force, so the zipper phenomenon is more likely to occur when the protective film is peeled from the optical member at a high speed. Therefore, it is difficult to realize an adhesive composition system for an optical member protective film that has a good balance of low-speed peeling force and high-speed peeling force, is hard to cause zipper phenomenon when peeling at high speed, and has excellent transparency.

The problem to be solved by the present invention is to provide an adhesive composition for an optical member protective film and an optical member protective film. The adhesive composition for an optical member protective film can form a good balance of low-speed peeling force and high-speed peeling force, and can sufficiently suppress An adhesive layer with excellent transparency that may cause zipper phenomenon when peeled off at high speed. [Means to solve the problem]

The specific methods used to solve the problem include the following aspects. >1>An adhesive composition for optical component protective film, containing: The (meth)acrylic copolymer (A) contains a structural unit derived from n-butyl acrylate and a structural unit derived from a monomer having a hydroxyl group, and has a glass transition temperature of -40°C or less and a weight average molecular weight of more than 200,000 and The range below 2 million, The (meth)acrylic copolymer (B) contains a structural unit derived from n-butyl methacrylate and a structural unit derived from a monomer having a hydroxyl group. The glass transition temperature falls within the range of 0°C to 45°C and the weight The average molecular weight falls within the range of more than 10,000 and less than 200,000, and Isocyanate series crosslinking agent; The content of the (meth)acrylic copolymer (B) is in the range of 1 part by mass or more and 70 parts by mass or less with respect to 100 parts by mass of the (meth)acrylic copolymer (A). >2> The adhesive composition for an optical member protective film as described in >1>, wherein the glass transition temperature of the (meth)acrylic copolymer (A) falls between -70°C and -40°C range. >3> The adhesive composition for an optical member protective film as described in >1> or >2>, wherein the composition derived from n-butyl methacrylate in the (meth)acrylic copolymer (B) The content of the unit is 50% by mass or more with respect to all the structural units of the (meth)acrylic copolymer (B). >4> The adhesive composition for an optical member protective film as described in any one of >1>~>3>, wherein the above-mentioned (meth)acrylic copolymer (A) is derived from n-butyl acrylate The content of the structural unit of is 50% by mass or more with respect to all the structural units of the (meth)acrylic copolymer (A). >5> The adhesive composition for an optical member protective film as described in any one of >1>~>4>, wherein the (meth)acrylic copolymer (A) is derived from a monomer having a hydroxyl group The content of the structural unit of the body falls within the range of 0.7% by mass or more and 15% by mass or less with respect to all the structural units of the (meth)acrylic copolymer (A). >6> The adhesive composition for an optical member protective film as described in any one of >1>~>5>, wherein the (meth)acrylic copolymer (B) is derived from a monomer having a hydroxyl group The content of the structural unit of the body falls within the range of 0.7% by mass or more and 15% by mass or less with respect to all the structural units of the (meth)acrylic copolymer (B). >7> The adhesive composition for an optical member protective film as described in any one of >1>~>6>, wherein the content of the (meth)acrylic copolymer (B) is relative to the (methyl) ) 100 parts by mass of the acrylic copolymer (A) falls within the range of 3 parts by mass or more and 60 parts by mass or less. >8> The adhesive composition for an optical member protective film as described in any one of >1>~>7>, wherein the weight average molecular weight of the (meth)acrylic copolymer (B) falls within 10,000 Above and below 150,000. >9> The adhesive composition for an optical member protective film as described in any one of >1>~>8>, wherein the isocyanate-based crosslinking agent is hexamethylene diisocyanate. >10>A protective film for optical components, with: Substrate, and The adhesive layer is provided on the above-mentioned substrate and formed by using the adhesive composition for an optical member protective film as described in any one of >1>~>9>. [Effects of Invention]

According to the present invention, there is provided an adhesive composition for an optical member protective film capable of forming a good balance of low-speed peeling force and high-speed peeling force, sufficiently suppressing the zipper phenomenon that may be caused by high-speed peeling, and having excellent transparency, and Provide optical component protective film.

Hereinafter, specific embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented by adding appropriate changes within the scope of the object of the present invention.

In this manual, the numerical range indicated by "~" means the range that includes the numerical values before and after "~" as the minimum and maximum values. In this specification, within the numerical range described in stages, the upper limit or lower limit of a certain numerical range can be replaced with the upper limit or lower limit of the numerical range described in another stage. In addition, in the numerical range described in this specification, the upper limit or lower limit described in a certain numerical range may be replaced with the values shown in the examples. In this specification, a combination of two or more ideal aspects is a more ideal aspect. In this specification, when there are multiple substances belonging to each component, the amount of each component means the total amount of multiple substances unless specifically limited.

In this specification, "(meth)acrylic copolymer" means that the content of structural units derived from a monomer having a (meth)acrylic acid group is the percentage of all structural units (that is, the (meth)acrylic polymer) All constituent units) are copolymers of 50% by mass or more.

In this manual, "(meth)acrylic" includes terms of both "acrylic" and "methacrylic", and "(meth)acrylate" includes "acrylate" and "methacrylate" "The terms of both, "(meth)acryloyl" is a term that includes both "acryloyl" and "methacryloyl".

In this manual, "n-" means normal, "i-" means iso (iso), "s-" means secondary (secondary), and "t-" means tertiary.

In this specification, "adhesive composition" means a liquid or paste substance before the end of the crosslinking reaction. In this specification, the "adhesive layer" means a film made of a substance after the crosslinking reaction of the adhesive composition is completed. In this specification, "adherent body" means an optical member.

In this manual, "low-speed peeling force" means the adhesion measured when the protective film attached to the adherend is peeled off at a low speed (ie, 0.3m/min) at 180° in the longitudinal direction of the protective film from the adherend force. In addition, the detailed measurement method is shown in the Example mentioned later. In this specification, "appropriate low-speed peeling force" means an adhesive force with a strength that does not easily cause malfunctions such as peeling and offset from the adherend.

In this manual, "high-speed peeling force" means the adhesive force measured when the protective film attached to the adherend is peeled off at a high speed (that is, 30m/min) at 180° in the longitudinal direction of the protective film from the adherend . In addition, the detailed measurement method is shown in the Example mentioned later. In this specification, "appropriate high-speed peeling force" means the adhesive force with the strength that can be effectively peeled from the adherend.

In this specification, "adhesive layer with a good balance of low-speed peeling force and high-speed peeling force" means an adhesive layer with a strength that is not prone to peeling and shifting from the adherend and can effectively peel off from the adherend. The adhesive layer of strength.

This manual also abbreviates "protective film for optical member" as "protective film".

[Adhesive composition for optical member protective film] The adhesive composition for an optical member protective film of the present invention (hereinafter also referred to as "adhesive composition") contains: The (meth)acrylic copolymer (A) contains a structural unit derived from n-butyl acrylate and a structural unit derived from a monomer having a hydroxyl group, and has a glass transition temperature of -40°C or less and a weight average molecular weight of more than 200,000 and The range of 2 million or less [hereinafter also referred to as specific (meth)acrylic copolymer (A)"], The (meth)acrylic copolymer (B) contains a structural unit derived from n-butyl methacrylate and a structural unit derived from a monomer having a hydroxyl group. The glass transition temperature falls within the range of 0°C to 45°C and the weight The average molecular weight falls within the range of 10,000 or more and 200,000 or less [hereinafter also referred to as the specific (meth)acrylic copolymer (B)"], and Isocyanate series crosslinking agent; The content of the specific (meth)acrylic copolymer (B) falls within the range of 1 part by mass to 70 parts by mass with respect to 100 parts by mass of the specific (meth)acrylic copolymer (A). According to the adhesive composition of the present invention, a low-speed peeling force and a high-speed peeling force are well balanced, a zipper phenomenon that may be caused when peeling at a high speed is sufficiently suppressed, and an adhesive layer with excellent transparency can be formed. The reason why the adhesive composition of the present invention can exert such effects has not yet been clarified, but the present inventors speculate as follows. However, the following hypothesis is not intended to limit the explanation of the adhesive composition of the present invention, and is only described as an example.

The glass transition temperature of the specific (meth)acrylic copolymer (B) contained in the adhesive composition of the present invention is 0° C. or more, and the weight average molecular weight falls within the range of 10,000 or more and 200,000 or less. In addition, the content of the specific (meth)acrylic copolymer (B) in the adhesive composition of the present invention is 1 part by mass or more relative to 100 parts by mass of the specific (meth)acrylic copolymer (A), and Range of 70 parts by mass or less. Therefore, it is considered that in the adhesive layer formed by the adhesive composition of the present invention, the specific (meth)acrylic copolymer (B) moderately concentrates in the vicinity of the surface (the so-called vicinity of the interface with the adherend). It is presumed that if the specific (meth)acrylic copolymer (B) is moderately concentrated near the interface with the adherend in the adhesive layer, the adhesive layer will not wet the adherend excessively, so the adhesive layer will Demonstrate appropriate high-speed peel strength. In addition, it is considered that the glass transition temperature of the specific (meth)acrylic copolymer (B) is 45° C. or lower, so that the adhesive layer can properly wet the adherend. Therefore, it is speculated that the adhesive layer formed by the adhesive composition of the present invention can suppress the zipper phenomenon caused by insufficient wetting of the adhesive layer to the adherend.

The glass transition temperature of the specific (meth)acrylic copolymer (A) contained in the adhesive composition of the present invention falls below -40°C and the weight average molecular weight falls within the range of 200,000 to 2 million. Therefore, it is presumed that the adhesive layer formed using the adhesive composition of the present invention will exhibit an appropriate low-speed peeling force. In addition, it is estimated that the adhesive layer formed by the adhesive composition of the present invention can sufficiently suppress the zipper phenomenon that may be caused when peeling off at a high speed.

The adhesive composition of the present invention contains a specific (meth)acrylic copolymer (A) and a specific (meth)acrylic copolymer (B) of different monomer compositions. Generally, an adhesive layer formed by an adhesive composition containing two or more copolymers of different monomer compositions is likely to cause the problem of reduced transparency (so-called haze increase). The specific (meth)acrylic copolymer (A) contained in the adhesive composition of the present invention contains structural units derived from n-butyl acrylate, and the specific (meth)acrylic copolymer (B) contains normal The constituent unit of butyl ester. Since the specific (meth)acrylic copolymer (A) and the specific (meth)acrylic copolymer (B) both contain a structural unit derived from a monomer having a n-butyl group, they tend to exhibit good compatibility. Therefore, it is estimated that the adhesive layer formed using the adhesive composition of the present invention has excellent transparency.

The specific (meth)acrylic copolymer (A) and the specific (meth)acrylic copolymer (B) contained in the adhesive composition of the present invention both contain structural units derived from a monomer having a hydroxyl group. Cross-linking reaction with isocyanate-based cross-linking agent appropriately proceeds. Therefore, it is estimated that the low-speed peeling force and the high-speed peeling force of the adhesive layer formed using the adhesive composition of the present invention have a good balance. In addition, it is estimated that the adhesive layer formed by the adhesive composition of the present invention can sufficiently suppress the zipper phenomenon that may be caused when peeling off at a high speed.

In contrast to the adhesive composition of the present invention, the pressure sensitive adhesive for protective sheets described in JP 2005-146151 A contains two types of (meth)acrylic polymers, but the (methyl) ) The glass transition temperature (Tg) of the acrylic polymer is 80°C or higher, so the formed adhesive layer does not wet the adherend sufficiently. For example, the zipper phenomenon cannot be sufficiently suppressed when the peeling speed is 30m/min. The adhesive composition described in JP 2013-216769 A contains two types of copolymers, but the glass transition temperature (Tg) of the (meth)acrylic polymer (B) is 59°C or higher, so it is considered to be compatible Similarly to the pressure-sensitive adhesive for protective sheets described in Japanese Patent Application Laid-Open No. 2005-146151, the formed adhesive layer does not sufficiently wet the adherend, for example, it cannot be sufficiently suppressed when the peeling speed is 30m/min. Zipper phenomenon. In addition, the two types of copolymers contained in the adhesive composition described in JP 2013-216769 A have very different monomer compositions, so the transparency of the adhesive layer is insufficient. The adhesive composition described in JP 2017-128636 A contains two types of (meth)acrylic copolymers. However, the (meth)acrylic copolymers, which are oligomers, contain alkylene oxide chains. It is thought that it will excessively promote the wetting of the formed adhesive layer to the adherend, and the high-speed peel force will become too high. Therefore, the low-speed peeling force and the high-speed peeling force of the adhesive layer formed using the adhesive composition described in JP 2017-128636 A are not well balanced (for example, refer to Comparative Example 16 described later).

Hereinafter, in this specification, "specific (meth)acrylic copolymer (A) and specific (meth)acrylic copolymer (B)" are collectively referred to as "specific (meth)acrylic copolymer".

[Specific (meth)acrylic copolymer (A)] The adhesive composition of the present invention contains a structural unit derived from n-butyl acrylate and a structural unit derived from a monomer having a hydroxyl group, the glass transition temperature is -40°C or less, and the weight average molecular weight falls between 200,000 and 2 million. The range of (meth)acrylic copolymer (A) [that is, specific (meth)acrylic copolymer (A)].

>Constituted unit from n-butyl acrylate> The specific (meth)acrylic copolymer (A) contains a structural unit derived from n-butyl acrylate. In this specification, "the structural unit derived from n-butyl acrylate" means a structural unit formed by addition polymerization of n-butyl acrylate.

The content rate of the structural unit derived from n-butyl acrylate in the specific (meth)acrylic copolymer (A) (so-called content ratio; the same applies hereinafter) is not particularly limited. The content of the structural unit derived from n-butyl acrylate in the specific (meth)acrylic copolymer (A) is preferably 40% by mass relative to all the structural units of the specific (meth)acrylic copolymer (A). Above, it is more preferably 45% by mass or more, and even more preferably 50% by mass or more. When the content of the structural units derived from n-butyl acrylate in the specific (meth)acrylic copolymer (A) is 40% by mass or more with respect to all the structural units of the specific (meth)acrylic copolymer (A), The compatibility with the (meth)acrylic copolymer (B) will become better, so there is a tendency to form an adhesive layer with more suppressed haze. In addition, the content of the structural unit derived from n-butyl acrylate in the specific (meth)acrylic copolymer (A) is preferably 70, for example, relative to all the structural units of the specific (meth)acrylic copolymer (A) Less than mass%. When the content of the structural unit derived from n-butyl acrylate in the specific (meth)acrylic copolymer (A) is 70% by mass or less with respect to all the structural units of the specific (meth)acrylic copolymer (A), There is a tendency to form an adhesive layer with a better balance of low-speed peeling force and high-speed peeling force.

>Constituted units from monomers with hydroxyl groups> The specific (meth)acrylic copolymer (A) contains a structural unit derived from a monomer having a hydroxyl group. In this specification, "a structural unit derived from a monomer having a hydroxyl group" means a structural unit formed by addition polymerization of a monomer having a hydroxyl group.

The type of monomer having a hydroxyl group is not particularly limited. Specific examples of monomers having a hydroxyl group include: 2-hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, (methyl) ) 3-hydroxypropyl acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, (meth)acrylic acid -12-Hydroxylauryl ester, 3-methyl-3-hydroxybutyl (meth)acrylate, 1,1-dimethyl-3-hydroxybutyl (meth)acrylate, (meth)acrylic acid- 1,3-Dimethyl-3-hydroxybutyl ester, (meth)acrylic acid-2,2,4-trimethyl-3-hydroxypentyl ester, (meth)acrylic acid-2-ethyl-3-hydroxyl Hydroxyalkyl (meth)acrylates such as hexyl ester, N-hydroxyethyl (meth)acrylamide, etc.; 1,4-cyclohexanedimethanol monoacrylate, dicaprolactone-2-propenyloxy Ether and so on. Among them, the monomer having a hydroxyl group is preferably a hydroxyalkyl (meth)acrylate from the viewpoint of good copolymerization with n-butyl acrylate, for example. (Meth) hydroxyalkyl acrylate, for example, in consideration of good compatibility with n-butyl acrylate and good copolymerization, and good reactivity with isocyanate-based crosslinking agent, it is preferable to have a carbon number of 1~ The hydroxyalkyl (meth)acrylate of 5-hydroxyalkyl is more preferably the hydroxyalkyl (meth)acrylate having a hydroxyalkyl with carbon number of 2 to 4.

The specific (meth)acrylic copolymer (A) may contain only one type of structural unit derived from a monomer having a hydroxyl group, or may contain two or more types.

The content rate of the structural unit derived from the monomer having a hydroxyl group in the specific (meth)acrylic copolymer (A) is not particularly limited, for example, relative to all the structural units of the specific (meth)acrylic copolymer (A) , Should fall within the range of 0.1% by mass or more and 20% by mass or less, more preferably within the range of 0.7% by mass or more and 15% by mass or less, and even more preferably within the range of 1% by mass or more and 10% by mass or less. The content of the structural unit derived from the monomer having a hydroxyl group in the specific (meth)acrylic copolymer (A) is 0.1% by mass or more relative to all the structural units of the specific (meth)acrylic copolymer (A) It means that the specific (meth)acrylic copolymer (A) actively contains a structural unit derived from a monomer having a hydroxyl group. When the specific (meth)acrylic copolymer (A) has a hydroxyl-containing monomer-derived structural unit content of 20% by mass or less relative to all the structural units of the specific (meth)acrylic copolymer (A) , There is a tendency to form an adhesive layer that can more fully suppress the zipper phenomenon that may be caused when peeling off at a high speed. And there is a tendency to form an adhesive layer with better transparency.

>Constituted units from alkyl (meth)acrylate monomers different from n-butyl acrylate> The specific (meth)acrylic copolymer (A) preferably contains an alkyl (meth)acrylate monomer different from n-butyl acrylate [hereinafter also referred to as other (meth)acrylic acid alkyl ester monomers (a) )”]. The structural unit derived from the other alkyl (meth)acrylate monomer (a) contributes to the adjustment of the adhesive force of the adhesive layer.

In this specification, "the structural unit derived from the other alkyl (meth)acrylate monomer (a)" means the structural unit formed by the addition polymerization of the other alkyl (meth)acrylate monomer (a).

If the other alkyl (meth)acrylate monomer (a) is an alkyl (meth)acrylate monomer different from n-butyl acrylate, the type is not particularly limited. The other alkyl (meth)acrylate monomers (a) are preferably unsubstituted alkyl (meth)acrylate monomers. The alkyl group of the other alkyl (meth)acrylate monomer (a) may be linear, branched, or cyclic. In addition, the carbon number of the alkyl group is preferably 1-18, more preferably 1-12 from the viewpoint of the adhesion of the formed adhesive layer to the adherend and the adhesion to the base material of the protective film.

Other alkyl (meth)acrylate monomers (a) include: methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl methacrylate, isobutyl (meth)acrylate, ( 2-Butyl (meth)acrylate, 3-Butyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, N-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, stearyl (meth)acrylate, (meth)acrylate Base) lauryl acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, etc. Among them, other alkyl (meth)acrylate monomers (a), for example, consider the viewpoint that the glass transition temperature (Tg) of the specific (meth)acrylic copolymer (A) can be easily adjusted to -40°C or less, Preferably, it is 2-ethylhexyl acrylate (2EHA).

When the specific (meth)acrylic copolymer (A) contains structural units derived from other alkyl (meth)acrylate monomers (a), it may contain only one type derived from other alkyl (meth)acrylate monomers The structural unit of (a) may contain two or more types.

When the specific (meth)acrylic copolymer (A) contains structural units derived from other alkyl (meth)acrylate monomers (a), the specific (meth)acrylic copolymer (A) is derived from other ( The content of the structural units of the alkyl meth)acrylate monomer (a) is preferably 10% by mass to 59.9% by mass relative to all the structural units of the specific (meth)acrylic copolymer (A). It is more preferable to fall within the range of 15% by mass or more and 50% by mass or less, and more preferably within the range of 20% by mass or more and 40% by mass or less.

>Constituted units derived from monomers having carboxyl groups> The specific (meth)acrylic copolymer (A) may contain a structural unit derived from a monomer having a carboxyl group. If the specific (meth)acrylic copolymer (A) contains structural units derived from a monomer having a carboxyl group, the high-speed peeling force of the formed adhesive layer will decrease, and the balance between low-speed peeling force and high-speed peeling force will become better The tendency.

In this specification, "a structural unit derived from a monomer having a carboxyl group" means a structural unit formed by addition polymerization of a monomer having a carboxyl group.

The type of the monomer having a carboxyl group is not particularly limited. Specific examples of monomers having a carboxyl group include: acrylic acid (AA), methacrylic acid (MAA), crotonic acid, maleic anhydride, fumaric acid, itaconic acid, glutaconic acid, citraconic acid, ω-carboxyl group -Polycaprolactone mono(meth)acrylate [e.g. ω-carboxy-polycaprolactone (n≒2) monoacrylate], succinate (e.g. 2-propenyloxyethyl-succinic acid) and the like. Among them, the monomer having a carboxyl group is preferably acrylic acid (AA) in view of good reactivity with an isocyanate-based crosslinking agent, for example.

When a specific (meth)acrylic copolymer (A) contains the structural unit derived from the monomer which has a carboxyl group, it may contain only 1 type of structural unit derived from the monomer which has a carboxyl group, and may contain 2 or more types.

When the specific (meth)acrylic copolymer (A) contains a structural unit derived from a monomer having a carboxyl group, the content of a structural unit derived from a monomer having a carboxyl group in the specific (meth)acrylic copolymer (A) With respect to all the structural units of the specific (meth)acrylic copolymer (A), it is preferable to fall within the range of 0.1% by mass to 5% by mass, and more preferably within the range of 0.3% by mass to 3% by mass, It is more preferable to fall within the range of 0.5% by mass or more and 1.5% by mass or less. When the specific (meth)acrylic copolymer (A) has a carboxyl-containing monomer-derived structural unit content of 0.1% by mass or more relative to all the structural units of the specific (meth)acrylic copolymer (A) , There will be a tendency for the high-speed peeling force of the formed adhesive layer to be even lower. When the specific (meth)acrylic copolymer (A) has a carboxyl-containing monomer-derived structural unit content of 5% by mass or less relative to all the structural units of the specific (meth)acrylic copolymer (A) , There is a tendency to form an adhesive layer that can more fully suppress the zipper phenomenon that may be caused when peeling off at a high speed.

>Other building blocks> The specific (meth)acrylic copolymer (A) may contain structural units other than the aforementioned structural units (so-called other structural units) within the range where the effects of the present invention can be exerted. The aforementioned structural units are also essential structural units. The structural unit derived from n-butyl acrylate and the structural unit derived from the monomer having a hydroxyl group, and the structural unit derived from the other alkyl (meth)acrylate monomer (a) of any structural unit and the monomer derived from the carboxyl group Component unit.

The monomer constituting the other structural unit is not particularly limited as long as it can be copolymerized with the monomer constituting the aforementioned structural unit. Examples of monomers constituting other structural units include: (meth)acrylates with cyclic groups represented by benzyl (meth)acrylate and phenoxyethyl (meth)acrylate; Methoxyethyl acrylate and ethoxyethyl (meth)acrylate are represented by alkoxyalkyl (meth)acrylates; styrene, α-methylstyrene, tertiary butylstyrene, Aromatic monovinyl monomers represented by p-chlorostyrene, chloromethyl styrene, and vinyl toluene; vinyl cyanide monomers represented by acrylonitrile and methacrylonitrile; and vinyl formate, Vinyl acetate, vinyl propionate, and vinyl versatic acid are representative vinyl esters. Various derivatives of these monomers can also be cited. However, when the specific (meth)acrylic copolymer (A) contains a structural unit derived from a (meth)acrylate having a cyclic group, the specific (meth)acrylic copolymer (A) is derived from a cyclic The content rate of the structural unit of the base (meth)acrylate, for example, considering the transparency of the formed adhesive layer, it is preferably 10 relative to all the structural units of the specific (meth)acrylic copolymer (A) Mass% or less, more preferably 5 mass% or less, and even more preferably 1 mass% or less, the specific (meth)acrylic copolymer (A) does not contain structural units derived from (meth)acrylate having a cyclic group That is, 0% by mass is particularly good.

>>Glass transition temperature of specific (meth)acrylic copolymer (A)>> The glass transition temperature (Tg) of the specific (meth)acrylic copolymer (A) is -40°C or lower, preferably -50°C or lower, more preferably -55°C or lower, and even more preferably -60°C or lower. If the glass transition temperature (Tg) of the specific (meth)acrylic copolymer (A) is below -40℃, the high-speed peeling force will not become too high, and it can form an adhesive with a good balance of low-speed peeling force and high-speed peeling force. Floor. In addition, an adhesive layer can be formed that can sufficiently suppress the zipper phenomenon that may be caused when peeling off at a high speed. The lower limit of the glass transition temperature (Tg) of the specific (meth)acrylic copolymer (A) is not particularly limited. For example, considering the adhesive force to the adherend, it is preferably -70°C or higher.

The glass transition temperature (Tg) of the specific (meth)acrylic copolymer (A) is the absolute temperature (unit: K; the same for the following) calculated by the following formula 1 converted into Celsius temperature (unit: °C; below Are the same). 1/Tg=m1/Tg1+m2/Tg2+...+m(k-1)/Tg(k-1)+mk/Tgk　(Equation 1)

In formula 1, Tg1, Tg2,..., Tg(k-1), and Tgk respectively represent the absolute temperature when each monomer constituting the specific (meth)acrylic copolymer (A) is made into a homopolymer (K) represents the glass transition temperature (Tg). m1, m2,..., m(k-1), and mk respectively represent the molar fraction of each monomer constituting the specific (meth)acrylic copolymer (A), and m1+m2+...+ m(k-1)+mk=1. In addition, by subtracting 273 from the absolute temperature (K), the absolute temperature (K) can be converted to Celsius (℃), and by adding 273 from the Celsius temperature (℃), the Celsius temperature (℃) can be converted to absolute temperature. (K).

In this specification, "the glass transition temperature (Tg) expressed in absolute temperature (K) when the homopolymer is made" means the absolute temperature (K) of the homopolymer obtained by polymerizing the monomer alone The glass transition temperature (Tg). The glass transition temperature (Tg) of the homopolymer was measured using a differential scanning calorimetry device (DSC) [model: EXSTAR6000, manufactured by Seiko Instruments (stock)], in a nitrogen stream, measuring a sample of 10 mg, and a heating rate of 10°C/min. The conditions are measured, and the inflection point of the obtained DSC curve is taken as the glass transition temperature (Tg) of the homopolymer.

For the representative monomer "Glass transition temperature (Tg) expressed in Celsius (°C) when it is made into a homopolymer", 2-ethylhexyl acrylate (2EHA) is -76°C. 2-ethylhexyl acrylate (2EHMA) at -10°C, n-butyl acrylate (n-BA) at -57°C, n-butyl methacrylate (n-BMA) at 21°C, tertiary butyl acrylate Ester (t-BA) is 41℃, tertiary butyl methacrylate (t-BMA) is 107℃, isobutyl methacrylate (i-BMA) is 48℃, and methyl acrylate (MA) is 5℃ , Methyl methacrylate (MMA) is 103°C, isobornyl methacrylate (IBXMA) is 155°C, isobornyl acrylate (IBXA) is 96°C, cyclohexyl methacrylate (CHMA) is 56°C, Ethyl acrylate (EA) is -27°C, ethyl methacrylate (EMA) is 42°C, methacrylic acid is 185°C, 4-hydroxybutyl acrylate (4HBA) is -39°C, 2-hydroxy acrylic acid Ethyl (2HEA) is -15°C, 2-hydroxyethyl methacrylate (2HEMA) is 55°C, acrylic acid (AA) is 163°C, isooctyl acrylate (i-OA) is -75°C, methyl Dimethylaminoethyl acrylate (DM) is 18℃, ω-carboxy-polycaprolactone (n≒2) monoacrylate is -30℃, and 2-propenoxyethyl-succinic acid is -40 ℃.

>>Weight average molecular weight of specific (meth)acrylic copolymer (A)>> The weight average molecular weight (Mw) of the specific (meth)acrylic copolymer (A) falls in the range of 200,000 or more and 2 million or less, preferably in the range of 250,000 or more and 1 million or less, and falls in the range of 300,000 or more and The range below 800,000 is even better, and the range above 350,000 and below 550,000 is even better. When the weight average molecular weight (Mw) of the specific (meth)acrylic copolymer (A) is 200,000 or more, it tends to be easy to obtain cohesive force. When the weight average molecular weight (Mw) of the specific (meth)acrylic copolymer (A) is 2 million or less, the coating properties tend to be easily optimized.

The weight average molecular weight (Mw) of the specific (meth)acrylic copolymer (A) is a value measured by the following method. Specifically, the measurement was performed according to the following (1) to (3). (1) The solution of the specific (meth)acrylic copolymer (A) is applied to release paper and dried at 100°C for 1 minute to obtain a film of the specific (meth)acrylic copolymer (A). (2) Using the film-like specific (meth)acrylic copolymer (A) obtained in (1) above and tetrahydrofuran, a sample solution with a solid content concentration of 0.2% by mass is obtained. (3) Using gel permeation chromatography (GPC), under the following conditions, the weight average molecular weight (Mw) of the specific (meth)acrylic copolymer (A) is measured as a standard polystyrene conversion value.

~Conditions~ Measuring device: High-speed GPC [Model: HLC-8220 GPC, manufactured by Tosoh Corporation] Detector: Differential Refractometer (RI) [Assembled in HLC-8220, manufactured by Tosoh Corporation] String: Connect 4 TSK-GEL GMHXL [manufactured by Tosoh Corporation] in series Column temperature: 40℃ Mobile phase: Tetrahydrofuran Sample concentration: 0.2% by mass Injection volume: 100μL Flow rate: 0.6mL/min

>>Specific (meth)acrylic copolymer (A) content rate>> The content rate of the specific (meth)acrylic copolymer (A) in the adhesive composition of the present invention is not particularly limited. For example, the content of the specific (meth)acrylic copolymer (A) in the adhesive composition is preferably 50% by mass or more relative to the total solid content in the adhesive composition. The range of 99 mass% or less is more preferably the range of 60 mass% or more and 90 mass% or less, and the range of 70 mass% or more and 80 mass% or less is even more preferable. If the content of the specific (meth)acrylic copolymer (A) in the adhesive composition of the present invention is 50% by mass or more relative to the total solid content in the adhesive composition, the formation can be more fully suppressed The tendency of the adhesive layer of the zipper phenomenon that may be caused by high-speed peeling. If the content of the specific (meth)acrylic copolymer (A) in the adhesive composition of the present invention is 99% by mass or less relative to the total solid content in the adhesive composition, a low-speed peeling force can be formed The tendency of the adhesive layer to have a better balance with high-speed peeling force. In this specification, "the total solid content in the adhesive composition" means the total mass of the adhesive composition when the adhesive composition does not contain volatile components such as solvents. In terms of ingredients, it means the mass of the residue obtained by removing volatile components such as solvent from the adhesive composition.

[Specific (meth)acrylic copolymer (B)] The adhesive composition of the present invention contains a structural unit derived from n-butyl methacrylate and a structural unit derived from a monomer having a hydroxyl group, the glass transition temperature falls within the range of 0°C or more and 45°C or less, and the weight average molecular weight falls within the range (Meth)acrylic copolymer (B) [that is, specific (meth)acrylic copolymer (B)] in the range of 10,000 or more and 200,000 or less. In addition, the content of the specific (meth)acrylic copolymer (B) in the adhesive composition of the present invention is 1 part by mass or more relative to 100 parts by mass of the specific (meth)acrylic copolymer (A), and Range of 70 parts by mass or less.

>Constituted unit from n-butyl methacrylate> The specific (meth)acrylic copolymer (B) contains a structural unit derived from n-butyl methacrylate. In this specification, "the structural unit derived from n-butyl methacrylate" means a structural unit formed by addition polymerization of n-butyl methacrylate.

The content rate of the structural unit derived from n-butyl methacrylate in a specific (meth)acrylic-type copolymer (B) is not specifically limited. The content of the structural unit derived from n-butyl methacrylate in the specific (meth)acrylic copolymer (B) is preferably 40 relative to all the structural units of the specific (meth)acrylic copolymer (B), for example Mass% or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more. The content of the structural units derived from n-butyl methacrylate in the specific (meth)acrylic copolymer (B) is 40% by mass or more relative to all the structural units of the specific (meth)acrylic copolymer (B) In this case, since the compatibility with the (meth)acrylic copolymer (A) becomes better, there is a tendency to form an adhesive layer with more suppressed haze. In addition, the content of the structural unit derived from n-butyl methacrylate in the specific (meth)acrylic copolymer (B) is preferably, for example, relative to all the structural units of the specific (meth)acrylic copolymer (B) It is 99.9% by mass or less, more preferably 98% by mass or less, and even more preferably 97% by mass or less. The content of structural units derived from n-butyl methacrylate in the specific (meth)acrylic copolymer (B) is 99.9% by mass or less relative to all the structural units of the specific (meth)acrylic copolymer (B) In this case, since it will be more appropriately crosslinked with the isocyanate-based crosslinking agent, there is a tendency to form an adhesive layer with a better balance of low-speed peeling force and high-speed peeling force.

>Constituted units from monomers with hydroxyl groups> The specific (meth)acrylic copolymer (B) contains a structural unit derived from a monomer having a hydroxyl group. In this specification, "a structural unit derived from a monomer having a hydroxyl group" means a structural unit formed by addition polymerization of a monomer having a hydroxyl group.

The type of monomer having a hydroxyl group is not particularly limited. The specific example of the monomer having a hydroxyl group is the same as the specific example of the monomer having a hydroxyl group in the specific (meth)acrylic copolymer (A), so the description thereof is omitted here. The monomer having a hydroxyl group is preferably a hydroxyalkyl (meth)acrylate from the viewpoint of good copolymerization with n-butyl methacrylate. (Meth) hydroxyalkyl acrylate, for example, from the viewpoint of good compatibility with n-butyl methacrylate and good copolymerizability, and good reactivity with isocyanate-based crosslinking agent, it is preferable to have a carbon number of The hydroxyalkyl (meth)acrylate of 1 to 5 hydroxyalkyl is more preferably the hydroxyalkyl (meth)acrylate having a hydroxyalkyl with 2 to 4 carbon atoms.

The specific (meth)acrylic copolymer (B) may contain only one type of structural unit derived from a monomer having a hydroxyl group, or may contain two or more types.

The content rate of the structural unit derived from the monomer having a hydroxyl group in the specific (meth)acrylic copolymer (B) is not particularly limited, for example, relative to all the structural units of the specific (meth)acrylic copolymer (B) It is preferable to fall within the range of 0.1% by mass to 20% by mass, more preferably within the range of 0.7% by mass to 15% by mass, and even more preferably within the range of 1% by mass to 10% by mass. The specific (meth)acrylic copolymer (B) has a content of structural units derived from a monomer having a hydroxyl group of 0.1% by mass or more with respect to all the structural units of the specific (meth)acrylic copolymer (B) It means that the specific (meth)acrylic copolymer (B) actively contains a structural unit derived from a monomer having a hydroxyl group. When the specific (meth)acrylic copolymer (B) has a hydroxyl-containing monomer-derived structural unit content of 20% by mass or less relative to all the structural units of the specific (meth)acrylic copolymer (B) , There is a tendency to form an adhesive layer with a better balance of low-speed peeling force and high-speed peeling force.

>Constituted units from alkyl (meth)acrylate monomers different from n-butyl methacrylate> The specific (meth)acrylic copolymer (B) preferably contains an alkyl (meth)acrylate monomer that is different from n-butyl methacrylate (hereinafter also referred to as other alkyl (meth)acrylate monomers) (b)”] The constituent unit. The structural unit derived from the other alkyl (meth)acrylate monomer (b) contributes to the adjustment of the adhesive force of the formed adhesive layer.

In this specification, "the structural unit derived from other alkyl (meth)acrylate monomer (b)" means a structural unit formed by addition polymerization of another alkyl (meth)acrylate monomer (b).

If the other alkyl (meth)acrylate monomer (b) is an alkyl (meth)acrylate monomer different from n-butyl methacrylate, the type is not particularly limited. The other alkyl (meth)acrylate monomers (b) are preferably unsubstituted alkyl (meth)acrylate monomers. The alkyl group of other (meth)acrylic acid alkyl ester monomer (b) may be linear, branched, or cyclic. In addition, the carbon number of the alkyl group is preferably 1-18, more preferably 1-12 from the viewpoint of the adhesion of the formed adhesive layer to the adherend and the adhesion to the base material of the protective film.

Other alkyl (meth)acrylate monomers (b) include: methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl acrylate (n-BA), isobutyl (meth)acrylate Ester, secondary butyl (meth)acrylate, tertiary butyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethyl (meth)acrylate Hexyl ester, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, stearyl (meth)acrylate , Lauryl (meth)acrylate, etc. Among them, other alkyl (meth)acrylate monomers (b), for example, are considered to have good copolymerizability with n-butyl methacrylate (n-BMA) and can easily achieve expectations due to proper glass transition temperature (Tg) From the viewpoint of the adhesion performance, ethyl methacrylate (EMA) is preferred. In addition, the other alkyl (meth)acrylate monomer (b) is preferably n-butyl acrylate (n-BA) from the viewpoint of compatibility with the specific (meth)acrylic copolymer (A), for example.

When the specific (meth)acrylic copolymer (B) contains structural units derived from other alkyl (meth)acrylate monomers (b), it may contain only one type derived from other alkyl (meth)acrylate monomers The structural unit of (b) may contain two or more types.

When the specific (meth)acrylic copolymer (B) contains a structural unit derived from another alkyl (meth)acrylate monomer (b), the specific (meth)acrylic copolymer (B) is derived from other ( The content of the structural units of the alkyl meth)acrylate monomer (b) is preferably 0.1% by mass to 59.9% by mass relative to all the structural units of the specific (meth)acrylic copolymer (B). The scope.

>Constituted units derived from monomers having carboxyl groups> The specific (meth)acrylic copolymer (B) may contain a structural unit derived from a monomer having a carboxyl group. If the specific (meth)acrylic copolymer (B) contains constituent units derived from a monomer having a carboxyl group, the high-speed peeling force of the formed adhesive layer will decrease, and the balance between low-speed peeling force and high-speed peeling force will become better The tendency.

The type of the monomer having a carboxyl group is not particularly limited. The specific example of the monomer having a carboxyl group is the same as the specific example of the monomer having a carboxyl group in the specific (meth)acrylic copolymer (A), so the description thereof is omitted here. The monomer having a carboxyl group is preferably acrylic acid (AA) from the viewpoint of good reactivity with an isocyanate-based crosslinking agent.

When a specific (meth)acrylic copolymer (B) contains the structural unit derived from the monomer which has a carboxyl group, it may contain only 1 type of structural unit derived from the monomer which has a carboxyl group, and may contain 2 or more types.

When the specific (meth)acrylic copolymer (B) contains a structural unit derived from a monomer having a carboxyl group, the content of a structural unit derived from a monomer having a carboxyl group in the specific (meth)acrylic copolymer (B) With respect to all the structural units of the specific (meth)acrylic copolymer (B), it is preferable to fall within the range of 0.1% by mass or more and 5% by mass or less, and more preferably within the range of 0.3% by mass or more and 3% by mass or less, It is more preferable to fall within the range of 0.5% by mass or more and 1.5% by mass or less. When the specific (meth)acrylic copolymer (B) has a carboxyl-containing monomer-derived structural unit content of 0.1% by mass or more relative to all the structural units of the specific (meth)acrylic copolymer (B) , There is a tendency to form an adhesive layer with a better balance of low-speed peeling force and high-speed peeling force. When the specific (meth)acrylic copolymer (B) has a carboxyl-containing monomer-derived structural unit content of 5% by mass or less relative to all the structural units of the specific (meth)acrylic copolymer (B) , There is a tendency to form an adhesive layer that can more fully suppress the zipper phenomenon that may be caused when peeling off at a high speed.

>Other building blocks> The specific (meth)acrylic copolymer (B) may contain structural units other than the aforementioned structural units (so-called other structural units) within the range in which the effects of the present invention can be exerted. The aforementioned structural units are also essential structural units. The structural unit derived from n-butyl methacrylate and the structural unit derived from the monomer having a hydroxyl group, and the structural unit derived from the other alkyl (meth)acrylate monomer (b) of any structural unit and the monomer having a carboxyl group The constituent unit of the body.

The monomer constituting the other structural unit is not particularly limited as long as it can be copolymerized with the monomer constituting the aforementioned structural unit. The specific examples of the monomers constituting the other structural units are the same as the specific examples of the monomers constituting the other structural units in the specific (meth)acrylic copolymer (A), so the description is omitted here.

>>Glass transition temperature of specific (meth)acrylic copolymer (B)>> The glass transition temperature (Tg) of the specific (meth)acrylic copolymer (B) falls within the range of 0°C or more and 45°C, preferably within the range of 5°C or more and 40°C, and falls within the range of 10°C or more. The range below 35°C is more preferable. When the glass transition temperature (Tg) of the specific (meth)acrylic copolymer (B) is 0°C or higher, an adhesive layer with a good balance of low-speed peeling force and high-speed peeling force can be formed. When the glass transition temperature (Tg) of the specific (meth)acrylic copolymer (B) is 45°C or less, an adhesive layer can be formed that can sufficiently suppress the zipper phenomenon that may be caused when peeling at high speed.

The glass transition temperature (Tg) of the specific (meth)acrylic copolymer (B) is calculated by the same method as the glass transition temperature (Tg) of the aforementioned specific (meth)acrylic copolymer (A) .

>>Weight average molecular weight of specific (meth)acrylic copolymer (B)>> The weight average molecular weight (Mw) of the specific (meth)acrylic copolymer (B) falls within the range of 10,000 or more and 200,000 or less, preferably within the range of 10,000 or more and 150,000 or less, and falls within the range of 15,000 or more and The range below 150,000 is even better, and the range below 20,000 and below 100,000 is even better. When the weight average molecular weight (Mw) of the specific (meth)acrylic copolymer (B) is 10,000 or more, an adhesive layer with a good balance of low-speed peeling force and high-speed peeling force can be formed. When the weight average molecular weight (Mw) of the specific (meth)acrylic copolymer (B) is 200,000 or less, an adhesive layer can be formed that can sufficiently suppress the zipper phenomenon that may be caused when peeling at high speed. In addition, the compatibility with the specific (meth)acrylic copolymer (A) is improved, so an adhesive layer with excellent transparency can be formed.

The weight average molecular weight (Mw) of the specific (meth)acrylic copolymer (B) is a value measured by the same method as the weight average molecular weight (Mw) of the aforementioned specific (meth)acrylic copolymer (A).

>>Content of specific (meth)acrylic copolymer (B)>> The content of the specific (meth)acrylic copolymer (B) in the adhesive composition of the present invention is 1 part by mass or more and 70 parts by mass relative to 100 parts by mass of the specific (meth)acrylic copolymer (A) The range of less than 3 parts by mass should preferably fall within the range of 3 parts by mass or more and 60 parts by mass or less, more preferably within the range of 10 parts by mass or more and 60 parts by mass, and more preferably within the range of 10 parts by mass or more and 50 parts by mass. Better. If the content of the specific (meth)acrylic copolymer (B) in the adhesive composition of the present invention is 1 part by mass or more relative to 100 parts by mass of the specific (meth)acrylic copolymer (A), a low speed can be formed An adhesive layer with a good balance of peeling force and high-speed peeling force. If the content of the specific (meth)acrylic copolymer (B) in the adhesive composition of the present invention is 70 parts by mass or less with respect to 100 parts by mass of the specific (meth)acrylic copolymer (A), it can be Adhesive layer that sufficiently suppresses the zipper phenomenon that may be caused when peeling off at high speed. In addition, an adhesive layer with excellent transparency can be formed.

[Method for manufacturing specific (meth)acrylic copolymer] The production method of the specific (meth)acrylic copolymer (A) and the specific (meth)acrylic copolymer (B) [that is, the specific (meth)acrylic copolymer] is not particularly limited. The specific (meth)acrylic copolymer can be produced by polymerizing the above-mentioned monomer by a known polymerization method typified by a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, and a bulk polymerization method, for example.

The glass transition temperature (Tg) of a specific (meth)acrylic copolymer can be adjusted suitably by using 2 or more types of monomers which differ in the glass transition temperature (Tg) at the time of making a homopolymer, for example. In addition, the weight average molecular weight (Mw) of a specific (meth)acrylic copolymer can be adjusted by adjusting the polymerization temperature, polymerization time, the amount of organic solvent used, the type of polymerization initiator, and the amount of polymerization initiator used. Pick the desired value.

Regarding the polymerization method, considering that when preparing the adhesive composition of the present invention after manufacturing, the processing steps are relatively simple and can be implemented in a short time, the solution polymerization method is preferable. The solution polymerization method usually involves feeding predetermined organic solvents, monomers, polymerization initiators, and chain transfer agents as needed into the polymerization tank, and under nitrogen flow and/or the reflux temperature of the organic solvent, It is heated and reacted for several hours while stirring. At this time, at least a part of the organic solvent, monomer, polymerization initiator, and/or chain transfer agent may be added sequentially.

Examples of the organic solvent used in the polymerization reaction include aromatic hydrocarbon compounds, aliphatic or alicyclic hydrocarbon compounds, ester compounds, ketone compounds, glycol ether compounds, and alcohol compounds. More specifically, the organic solvent used in the polymerization reaction includes, for example, benzene, toluene, ethylbenzene, n-propylbenzene, tertiary butylbenzene, o-xylene, meta-xylene, p-xylene, tetralin Aromatic hydrocarbon compounds represented by, decalin, and aromatic naphtha; n-hexane, n-heptane, n-octane, isooctane, n-decane, dipentene, petroleum spirit, petroleum naphtha , And aliphatic or cycloaliphatic hydrocarbon compounds represented by turpentine; ethyl acetate, n-butyl acetate, n-pentyl acetate, 2-hydroxyethyl acetate, 2-butoxyethyl acetate, acetic acid Ester compounds represented by -3-methoxybutyl ester and methyl benzoate; represented by acetone, methyl ethyl ketone, methyl isobutyl ketone, isophorone, cyclohexanone, and methyl cyclohexanone Ketone compounds; represented by ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether Glycol ether compounds; and alcohol compounds represented by methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, secondary butanol, and tertiary butanol. During the polymerization reaction, these organic solvents may be used alone or in combination of two or more kinds.

When manufacturing specific (meth)acrylic copolymers, it is preferable to use organic solvents that are not prone to chain transfer during polymerization, such as aromatic hydrocarbon compounds, ester compounds, ketone compounds, and alcohol compounds. In particular, consider specific (meth)acrylic copolymers. Toluene, ethyl acetate, methyl ethyl ketone, tertiary butanol, etc. are suitable from the viewpoints of solubility of the copolymer and ease of polymerization.

Examples of the polymerization initiator include organic peroxides and azo compounds generally used in solution polymerization. Examples of organic peroxides include: tertiary butyl hydroperoxide, cumene hydroperoxide, dicumyl peroxide, benzyl peroxide, laurel peroxide, hexyl peroxide, and dicarbonic acid peroxide. Diisopropyl ester, di-2-ethylhexyl peroxydicarbonate, tertiary butyl peroxytrimethyl acetate, 2,2-bis(4,4-di(tertiary butyl)peroxycyclohexyl) )Propane, 2,2-bis(4,4-bis(tertiary pentyl)peroxycyclohexyl)propane, 2,2-bis(4,4-bis(tertiary octyl)peroxycyclohexyl)propane , 2,2-bis(4,4-bis-α-cumylperoxycyclohexyl)propane, 2,2-bis(4,4-bis(tertiarybutyl)peroxycyclohexyl)butane , And 2,2-bis(4,4-bis(tertiary octyl)peroxycyclohexyl)butane. Examples of azo compounds include: 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile) (ABVN), 2,2'- Azobis(4-methoxy-2,4-dimethylvaleronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), and 2,2'-azobis( Isobutyric acid) dimethyl ester. During the polymerization reaction, these polymerization initiators may be used alone or in combination of two or more kinds.

When producing a specific (meth)acrylic copolymer, it is preferable to use a polymerization initiator that does not cause a graft reaction during the polymerization reaction, and it is particularly preferable to use an azobis-based polymerization initiator.

The amount of the polymerization initiator used is not particularly limited, and is appropriately set according to the molecular weight of the specific (meth)acrylic copolymer for the purpose.

In the production of a specific (meth)acrylic copolymer, a chain transfer agent may be used as needed, as long as it does not impair the purpose and effects of the present invention. Examples of chain transfer agents include: cyanoacetic acid, cyanoacetic acid alkyl ester compounds with carbon numbers 1 to 8, bromoacetic acid, bromoacetic acid alkyl ester compounds with carbon numbers 1 to 8, and α-methylstyrene, anthracene Aromatic compounds represented by phenanthrene, pyrene, and 9-phenyl pyridine; p-nitroaniline, nitrobenzene, dinitrobenzene, p-nitrobenzoic acid, p-nitrophenol, and p-nitrotoluene are Representative aromatic nitro compounds; benzoquinone and benzoquinone derivatives represented by 2,3,5,6-tetramethyl-p-benzoquinone; borane derivatives represented by tributylborane; tetrabromo Halogenated hydrocarbons represented by carbon, carbon tetrachloride, 1,1,2,2-tetrabromoethane, tribromoethylene, trichloroethylene, bromotrichloromethane, tribromomethane, and 3-chloro-1-propene Compounds; aldehyde compounds represented by chloral and furan formaldehyde; aromatic thiol compounds represented by alkyl mercaptan compounds with carbon numbers of 1 to 18, thiophenol and toluene mercaptan; carbons of thioglycolic acid and thioglycolic acid Alkyl ester compounds with 1 to 10, hydroxyalkyl mercaptan compounds with 1 to 12 carbons; and terpene compounds represented by pinene and terpinolene.

When manufacturing a specific (meth)acrylic copolymer, in the case of using a chain transfer agent, the amount of the chain transfer agent used is not particularly limited, and it is appropriate according to the molecular weight of the specific (meth)acrylic copolymer for the purpose To set.

The polymerization temperature is not particularly limited, and is appropriately set according to the molecular weight of the specific (meth)acrylic copolymer for the purpose.

[Isocyanate-based crosslinking agent] The adhesive composition of the present invention contains an isocyanate-based crosslinking agent. In the present specification, "isocyanate-based crosslinking agent" means a compound having two or more isocyanate groups in the molecule (so-called polyisocyanate compound). However, the isocyanate-based crosslinking agent in this specification does not include compounds having an isocyanate group, a polysiloxane structure, and an alkylene oxide structure. In this specification, a compound having an isocyanate group, a polysiloxane structure, and an alkylene oxide structure is referred to as a "polysiloxane-based isocyanate compound", and the details will be described later.

Examples of isocyanate-based crosslinking agents include aromatic polyisocyanate compounds such as xylylene diisocyanate (XDI), diphenylmethane diisocyanate, triphenylmethane triisocyanate, and toluene diisocyanate (TDI); hexamethylene diisocyanate (HMDI) ), aliphatic or alicyclic polyisocyanate compounds such as pentamethylene diisocyanate (PDI), isophorone diisocyanate, and hydrogenated aromatic polyisocyanate compounds. In addition, the isocyanate-based crosslinking agent may also include the dimer of the polyisocyanate compound, the trimer of the polyisocyanate compound, the pentamer of the polyisocyanate compound, the polyisocyanate compound and the polyol compound (for example, trimethylol Propyl propane), the biuret of the above-mentioned isocyanate compound, etc. Among them, the isocyanate-based crosslinking agent is preferably hexamethylene diisocyanate (HMDI) in consideration of the viewpoint that it is easy to exhibit the desired adhesive force and the viewpoint that the haze can be suppressed more.

Commercial products can be used for the polyisocyanate compound. Examples of commercially available products of polyisocyanate compounds include: "CORONATE (registered trademark) HX", "CORONATE (registered trademark) HL-S", "CORONATE (registered trademark) L", "CORONATE (registered trademark) L-45E ", "CORONATE (registered trademark) 2031", "CORONATE (registered trademark) 2030", "CORONATE (registered trademark) 2234", "CORONATE (registered trademark) 2785", "AQUANATE (registered trademark) 200", and "AQUANATE (Registered trademark) 210" [the above is Tosoh (stock) system]; "SUMIDUR (registered trademark) N-3300", "DESMODUR (registered trademark) N-3400", and "SUMIDUR (registered trademark) N-75" [The above is Sumika Covestro Urethane (stock) system]; "DURANATE (registered trademark) E-405-80T", "DURANATE (registered trademark) AE700-100", "DURANATE (registered trademark) 24A-100", and "DURANATE (Registered trademark) TSE-100" [Above is Asahi Kasei Co., Ltd.]; and "TAKENATE (registered trademark) D-110N", "TAKENATE (registered trademark) D-120N", "TAKENATE (registered trademark) M-631N ", "MT-OLESTER (registered trademark) NP1200", and "STABiO (registered trademark) XD-340N" [above are manufactured by Mitsui Chemicals Co., Ltd.].

In the adhesive composition of the present invention, the isocyanate-based crosslinking agent may contain only one type or two or more types.

The content of the isocyanate-based crosslinking agent in the adhesive composition of the present invention is not particularly limited, and it should preferably fall within the range of 0.1 parts by mass or more and 10.0 parts by mass relative to 100 parts by mass of the specific (meth)acrylic copolymer , It is more preferably within the range of 0.3 parts by mass or more and 7.0 parts by mass or less, more preferably within the range of 0.5 parts by mass or more and 6.0 parts by mass or less, and particularly preferably within the range of 1.0 parts by mass or more and 5.0 parts by mass or less. The content of the isocyanate-based crosslinking agent in the adhesive composition of the present invention is 0.1 parts by mass or more relative to 100 parts by mass of the specific (meth)acrylic copolymer, which means that the adhesive composition of the present invention actively contains isocyanate-based crosslinking agents. Joint agent. If the content of the isocyanate-based crosslinking agent in the adhesive composition of the present invention is 10.0 parts by mass or less relative to 100 parts by mass of the specific (meth)acrylic copolymer, there will be an adhesive layer that does not excessively cause the formation of The wetting of the adhesive body is reduced, and the adhesive layer will show a tendency of more appropriate low-speed peeling force. In addition, there is a tendency to more fully suppress the zipper phenomenon that may be caused when peeling off at a high speed.

[Organic solvents] The adhesive composition of the present invention may also contain an organic solvent. The organic solvent contributes to the improvement of the coatability of the adhesive composition. Examples of the organic solvent include the same organic solvents used in the polymerization reaction of the aforementioned specific (meth)acrylic copolymer.

When the adhesive composition of the present invention contains an organic solvent, the organic solvent may contain only one type or two or more types.

When the adhesive composition of the present invention contains an organic solvent, the content of the organic solvent is not particularly limited, and can be appropriately set according to the purpose.

[Other ingredients] The adhesive composition of the present invention may contain components other than the aforementioned components (so-called other components) as needed within a range that does not impair the effects of the present invention. Other components include: polysiloxane-based isocyanate compounds, polysiloxane-based compounds different from polysiloxane-based isocyanate compounds (hereinafter also referred to as "other polysiloxane compounds"), ionic compounds, specific (meth)acrylic acid Polymers other than copolymers, crosslinking agents other than isocyanate crosslinking agents (e.g. metal chelate crosslinking agents), crosslinking catalysts, tackifiers, antioxidants, colorants (e.g. dyes and pigments) , Light stabilizers (such as ultraviolet absorbers), etc.

>Polysiloxane isocyanate compound> In addition to the aforementioned isocyanate-based crosslinking agent, the adhesive composition of the present invention may also contain a compound having an isocyanate group, a polysiloxane structure, and an alkylene oxide structure (ie, a polysiloxane-based isocyanate compound). Since the polysiloxane-based isocyanate compound has an isocyanate group, it reacts with the cross-linkable functional group in the specific (meth)acrylic copolymer to form a cross-linked structure, and is easily held in the adhesive layer in an anchored state. Therefore, when the protective film is peeled off, the transfer of contaminating components to the surface of the adherend is inhibited. Therefore, if the adhesive composition of the present invention contains a silicone isocyanate compound, there is a tendency to form an adhesive layer with excellent stain resistance. In addition, since the polysiloxane isocyanate compound has a polysiloxane structure in the molecule, it is not easily compatible with the specific (meth)acrylic copolymer and tends to concentrate near the surface of the adhesive layer. In addition, since polysiloxane isocyanate compounds have an alkylene oxide structure in the molecule, they are concentrated in a state of being coordinated with an antistatic agent, just like the polysiloxane compound having an alkylene oxide structure used as an antistatic auxiliary agent. The tendency near the surface of the adhesive layer. Therefore, the polysiloxane-based isocyanate compound can provide excellent antistatic performance in a small amount with respect to the formed adhesive layer. In this specification, the "polysiloxane structure" means a structure formed by connecting siloxane groups (-Si-O-). The number of silicon atoms contained in the polysiloxane structure of the polysiloxane isocyanate compound should preferably fall within the range of 1-100.

The polysiloxane-based isocyanate compound can be obtained by a reaction between a polysiloxane compound having a reactive group and an alkylene oxide structure and an isocyanate compound (hereinafter also referred to as "pre-reaction").

The reactive group in the polysiloxane compound having a reactive group and an alkylene oxide structure can include: hydroxyl, carboxyl, substituted or unsubstituted amide, substituted or unsubstituted amine, epoxy, Reactive groups such as mercapto groups and silicon-containing groups. Among them, the reactive group can effectively promote the reaction between the reactive group and the isocyanate group (NCO group) in the isocyanate compound, and can effectively suppress the occurrence of contamination of the adherend, and the hydroxyl group is preferable. The reactive group can be introduced into any of the two ends, one end, and side chain of the polysiloxane compound having an alkylene oxide structure. Here, "one end" means, for example, one end of the main chain of a polysiloxane compound having a polysiloxane chain (so-called main chain) having a repeating unit of a siloxane group. "Two ends" means, for example, both ends of the above-mentioned main chain of a polysiloxane compound having a molecular chain (so-called main chain) having repeating units with siloxyalkyl groups.

Examples of the polysiloxane compound having a reactive group and an alkylene oxide structure include compounds in which an alkylene oxide structure is grafted to a polysiloxane chain (so-called polysiloxane main chain), or a ring A compound in which an oxane structure is bonded to a polysiloxane chain (so-called polysiloxane main chain) in a block-like manner. The compound having an alkylene oxide structure can be exemplified by polyethylene oxide, polypropylene oxide, etc. having a reactive group, and it can also be formed by blockwise or random addition of ethylene oxide and propylene oxide Of polyalkylene oxide.

The polysiloxane compound having a reactive group and an alkylene oxide structure, for example, considering that it exhibits excellent antistatic properties and effectively suppresses the contamination of the adherend, it is preferable to contain an alkylene oxide structure and an alkylene oxide structure. A polysiloxane compound with a hydroxyl group bonded to the end (hereinafter also referred to as a "polysiloxane compound containing a specific alkylene oxide structure"). If the polysiloxane compound containing a specific alkylene oxide structure has a structure in which a hydroxyl group is bonded to the end of the alkylene oxide structure, it can exhibit better pollution resistance. The polysiloxane compound having an alkylene oxide chain tends to interact with the antistatic agent described later and concentrate near the surface of the adhesive layer. As a result, it is estimated that the surface resistance value of the surface of the adhesive layer will decrease. If the adhesive composition contains a silicone isocyanate compound, the blending amount of the antistatic agent in the adhesive composition can be reduced.

Considering the viewpoint of imparting antistatic properties and reducing the pollution to the adherend, the polysiloxane compound containing a specific alkylene oxide structure should preferably contain a structural unit derived from dialkylsiloxane and an alkyl (hydroxypoly Alkyloxyalkyl) siloxane is a polysiloxane compound which is a constituent unit. The carbon number of the alkyl group in the dialkylsiloxane is preferably 1 to 4, more preferably 1. In addition, the number of carbon atoms in the alkylene oxide chain in the alkyl (hydroxypolyalkyleneoxyalkyl) siloxane is preferably 2 to 4, and more preferably 2 to 3. The content of the alkylene oxide chain in the alkyl (hydroxypolyalkyleneoxyalkyl) silicone is preferably 1-100, more preferably 10-100. The carbon number of the alkyl group in the alkyl (hydroxypolyalkyleneoxyalkyl) siloxane is preferably 1 to 4.

When the polysiloxane compound containing a specific alkylene oxide structure contains a structural unit derived from a dialkylsiloxane and a structural unit derived from an alkyl (hydroxypolyalkyleneoxyalkyl) siloxane, it is derived from a dialkyl silicon The content of the structural unit of the oxane is preferably 100 or less, more preferably 1 to 80. In addition, the content of the structural unit derived from the alkyl group (hydroxypolyalkyleneoxyalkyl) siloxane is preferably 2 to 100, more preferably 2 to 80.

Considering the viewpoints of adhesion, antistatic properties and reduction of pollution to the adherend, the polysiloxane compound containing a specific alkylene oxide structure is preferably a compound represented by the following general formula (3) or general formula (4).

[化1]

In the general formula (3), p is the repeating number of the dimethylsiloxane structural unit and represents an integer from 0 to 100. q is the repeating number of the methypropylene siloxane structural unit having a polyethylene oxide chain, and represents an integer from 2 to 100. a is the repeating number of the ethylene oxide structural unit, representing an integer of 1-100. Here, when the compound represented by the general formula (3) is an aggregate of multiple compounds, p, q, and a are the average values of the aggregate form of the compound, and are rational numbers.

The repeating number a of the ethylene oxide structural unit is an integer of 1-100, preferably an integer of 10-100. When a is 1 or more, sufficient conductivity may be obtained and the antistatic effect tends to be more improved. In addition, when a is 100 or less, it is easier to concentrate near the surface of the adhesive layer.

The repeating number p of the dimethylsiloxane structural unit is an integer from 0 to 100, preferably an integer from 1 to 80. When p is 0 or more, there is a tendency to improve the antistatic effect. In addition, when p is 100 or less, there is a tendency to improve compatibility with other components constituting the adhesive composition and further improve the transparency of the adhesive layer. The repeating number q of the structural unit of methacrylic siloxane is an integer of 2 to 100, preferably an integer of 2 to 80. If q is 2 or more, sufficient conductivity will be easily obtained and the antistatic effect will tend to be improved. In addition, if q is 100 or less, there is a tendency to improve compatibility with other components constituting the adhesive composition and further improve the transparency of the adhesive layer.

Specific examples of the compound represented by general formula (3) include: "SF-8428", "FZ-2162", "SH-3773M", "FZ-77", "FZ-2104", "FZ-2110", "L-7001", "L-7002", "SH-3749", etc. [The above is the Toray Dow Corning (share) system].

[化2]

In the general formula (4), R ¹ and R ² each independently represent an alkylene group having 1 to 6 carbon atoms, c represents an integer of 10 to 80, and d represents the repeating number of ethylene oxide (EO) constituent units, which represents An integer of 1 or more, e is the repeating number of the propylene oxide (PO) structural unit, and an integer of 0 or more, and d+e is an integer of 1-30. The order of ethylene oxide and propylene oxide may also be random.

Specific examples of the compound represented by the general formula (4) include "BY-16-201", "SF-8427", etc. [the above are manufactured by Toray Dow Corning Co., Ltd.].

The weight average molecular weight (Mw) of the polysiloxane compound containing a specific alkylene oxide structure is not particularly limited. For example, it should fall within the range of more than 10,000 and less than 20,000, and more preferably fall within the range of more than 3,000 and less than 15,000. . The weight average molecular weight (Mw) of the polysiloxane compound containing the specific alkylene oxide structure is a value measured by the same method as the weight average molecular weight (Mw) of the aforementioned specific (meth)acrylic copolymer (A).

The HLB value of the polysiloxane compound containing a specific alkylene oxide structure is not particularly limited. The HLB value of a polysiloxane compound containing a specific alkylene oxide structure, for example, is suitable from the viewpoints of compatibility with specific (meth)acrylic copolymers, ease of localization, and adhesion to protective films. It falls in the range of 5 or more and not up to 16, and it is more preferably in the range of 7 or more and 15 or less.

The HLB value is an indicator of the balance between the hydrophilicity and hydrophobicity of a polysiloxane compound with an alkylene oxide structure. This specification follows the definition of Griffin method for calculation by the following formula. In addition, when the polysiloxane having an alkylene oxide structure is a commercially available product, the catalog data of the commercially available product is preferred. HLB=[(Sum of chemical formula weight of hydrophilic part)/(Molecular weight of polysiloxane compound with alkylene oxide structure)]×20

The polysiloxane compound containing a specific alkylene oxide structure can be selected from the aforementioned commercially available products, or the organic compound with unsaturated bond and polyethylene oxide chain can be grafted to the organic compound with hydrogenated silicon by the hydrosilylation reaction. The main chain of dimethyl polysiloxane is obtained.

The isocyanate compound used for the preliminary reaction of the polysiloxane isocyanate compound is not particularly limited as long as it can react with the polysiloxane compound having a reactive group and an alkylene oxide structure. Examples of such an isocyanate compound include polyisocyanate compounds that are the aforementioned isocyanate-based crosslinking agents, and specific examples are the same as those of the isocyanate-based crosslinking agent.

For example, considering the viewpoint of reactivity in the pre-reaction, the isocyanate compound used in the pre-reaction is preferably selected from isophorone diisocyanate or xylylene diisocyanate, and isocyanuric acid of hexamethylene diisocyanate and polyol At least one of the modified acid esters is more preferably at least one of isophorone diisocyanate and xylylene diisocyanate from the viewpoint of particularly inhibiting gelation during the pre-reaction described later.

For example, from the viewpoint of antistatic properties, the isocyanate compound used in the preliminary reaction is preferably an isocyanate compound different from the polyisocyanate compound that is the aforementioned isocyanate-based crosslinking agent. If the isocyanate compound used in the pre-reaction of the isocyanate-based crosslinking agent, namely the polyisocyanate compound and the polysiloxane-based isocyanate compound, is different, in the adhesive layer, the aforementioned isocyanate-based crosslinking agent, that is, the polyisocyanate compound and the polysiloxane-based isocyanate Compounds are not easily compatible, and polysiloxane isocyanate compounds are more likely to concentrate on the surface of the adhesive layer, so there is a tendency to obtain better antistatic properties.

The isocyanate compound used for the preliminary reaction may be used alone or in two or more types. For example, when isophorone diisocyanate and xylylene diisocyanate are used in combination, there is a tendency to suppress gelation during the pre-reaction.

The polysiloxane isocyanate compound preferably contains a structure represented by the following structural formula (1).

[化3]

In the structural formula (1), r represents an integer from 1 to 100, b represents an integer from 1 to 100, and X represents a monovalent organic group containing an isocyanate group.

The repeating number r of the methacrylic siloxane structural unit is an integer from 1 to 100, preferably an integer from 2 to 80. If r is 1 or more, there is a tendency to obtain sufficient conductivity and improve antistatic properties. Also, if r is 100 or less, there is a tendency to improve compatibility with other components constituting the adhesive composition and improve the transparency of the adhesive layer.

The repeating number b of the ethylene oxide structural unit is an integer of 1-100, preferably an integer of 10-100. If b is 1 or more, there is a tendency to obtain sufficient conductivity and improve antistatic properties. In addition, if b is 100 or less, there is a tendency to improve compatibility with other components constituting the adhesive composition and improve the transparency of the adhesive layer.

Examples of the monovalent organic group represented by X include a monovalent group obtained by removing one isocyanate group (NCO group) from a polyisocyanate compound (that is, an isocyanate compound having a bifunctional or more) that is the aforementioned isocyanate-based crosslinking agent. Among them, the monovalent organic group represented by X, for example, considering the reactivity with a specific (meth)acrylic copolymer, is preferably selected from chain or cyclic aliphatic polyisocyanate compounds, chain Or at least one of a dimer of a cyclic aliphatic polyisocyanate compound, and a trimer or pentamer of a modified isocyanurate containing a chain or cyclic aliphatic polyisocyanate compound An isocyanate compound is a monovalent group obtained by removing one isocyanate group, and is a dimer selected from isophorone diisocyanate, xylylene diisocyanate, or hexamethylene diisocyanate and hexamethylene diisocyanate , And at least one polyisocyanate compound in the trimer or pentamer of the isocyanurate modified product containing hexamethylene diisocyanate is a monovalent group obtained by removing one isocyanate group, which is more preferably from At least one of isophorone diisocyanate, xylylene diisocyanate, and isocyanurate modified terpolymer containing hexamethylene diisocyanate is a monovalent group obtained by removing one isocyanate group Even more preferably, it is a monovalent group obtained by removing one isocyanate group from at least one of isophorone diisocyanate and xylylene diisocyanate. In addition, the monovalent organic group represented by X, for example, from the viewpoint of antistatic properties, it is preferable to remove one isocyanate group (NCO group) from another difunctional or higher isocyanate compound different from the aforementioned isocyanate-based crosslinking agent, which is the polyisocyanate compound. The resulting monovalent base.

A specific example of the structure represented by the above structural formula (1) is shown below. In addition, the structure represented by the structural formula (1) is not limited to the structure illustrated below, and for example, if it is a structure including the structure represented by the structural formula (1), it is not particularly limited.

[化4]

[化5]

[化6]

[化7]

[化8]

The polysiloxane-based isocyanate compound, for example, from the viewpoint of contamination resistance, is preferably at least one selected from the group consisting of compounds represented by general formula (1-1) and general formula (2), and is of general formula The compound represented by (1-1) is more preferable.

[化9]

In the general formula (1-1), p represents an integer from 0 to 100, q and r each independently represent an integer from 1 to 100, a represents an integer from 1 to 100, and b represents an integer from 1 to 100. In addition, X represents a monovalent organic group containing an isocyanate group. Here, when the compound represented by the general formula (1-1) is an aggregate of multiple compounds, p, q, r, a, and b are the average values of the aggregate form of the compound, and are rational numbers.

The repeating number a of the ethylene oxide structural unit is an integer of 1-100, preferably an integer of 10-100. If a is 1 or more, there is a tendency to obtain sufficient conductivity and improve antistatic properties. Moreover, if a is 100 or less, there is a tendency to improve compatibility with other components constituting the adhesive composition and improve the transparency of the adhesive layer.

The repeating number p of the dimethylsiloxane structural unit is an integer from 0 to 100, preferably an integer from 1 to 80. When p is 0 or more, there is a tendency to improve antistatic properties. In addition, if p is 100 or less, there is a tendency to improve compatibility with other components constituting the adhesive composition and improve the transparency of the adhesive layer. The repeating number q of the methacrylic acid structural unit is an integer from 1 to 100, preferably an integer from 2 to 80. If q is 1 or more, there is a tendency to obtain sufficient conductivity and improve antistatic properties. Also, if q is 100 or less, there is a tendency to improve compatibility with other components constituting the adhesive composition and improve the transparency of the adhesive layer.

In the general formula (1-1), r and b have the same meaning as r and b in the structural formula (1), and the ideal range is also the same.

[化10]

In the general formula (2), R ¹ and R ² each independently represent an alkylene group having 1 to 6 carbon atoms, c represents an integer of 10 to 80, and d is the repeating number of the ethylene oxide (EO) structural unit, which represents An integer of 1 or more, e is the repeating number of the propylene oxide (PO) structural unit, representing an integer of 0 or more, and d+e represents an integer of 1-30. The order of the ethylene oxide structural unit and the propylene oxide structural unit may also be random.

In the general formula (2), the alkylene group having 1 to 6 carbon atoms represented by R ¹ or R ² is not particularly limited, and examples thereof include methylene, ethylene, propylene, and butylene.

The repeating number d of the ethylene oxide structural unit is preferably an integer of 1-100, more preferably an integer of 10-100. If d is 1 or more, there is a tendency to obtain sufficient conductivity and improve antistatic properties. Furthermore, if d is 100 or less, there is a tendency to improve compatibility with other components constituting the adhesive composition and improve the transparency of the adhesive layer.

The repeating number e of the propylene oxide structural unit is preferably an integer from 1 to 100, and more preferably an integer from 10 to 100. If e is 1 or more, there is a tendency to obtain sufficient conductivity and improve antistatic properties. In addition, if e is 100 or less, there is a tendency to improve compatibility with other components constituting the adhesive composition and improve the transparency of the adhesive layer.

It is more preferable that the sum of the repeating number d of the ethylene oxide structural unit and the repeating number e of the propylene oxide structural unit is an integer of 1-50.

Specific examples of the polysiloxane-based isocyanate compound are shown below. In addition, the polysiloxane-based isocyanate compound is not limited to the compounds exemplified below, and if it is a compound containing a compound containing the structure represented by the aforementioned structural formula (1), it is not particularly limited.

[化11]

[化12]

[化13]

[化14]

[化15]

[化16]

[化17]

[化18]

[化19]

[化20]

[化21]

[化22]

[化23]

[化24]

[化25]

[化26]

The production method of the polysiloxane isocyanate compound is not particularly limited, and a known production method can be used. For example, by putting a predetermined amount of a polysiloxane compound having a reactive group and an alkylene oxide structure and an isocyanate compound into a reaction vessel, and uniformly stirring and reacting (pre-reaction), polysilicon can be obtained Oxygen isocyanate compound.

The temperature of the pre-reaction is preferably 40°C to 100°C, more preferably 45°C to 95°C, and even more preferably 50°C to 95°C.

When the adhesive composition of the present invention contains a silicone-based isocyanate compound, the content of the silicone-based isocyanate compound in the adhesive composition is preferably, for example, relative to 100 parts by mass of the specific (meth)acrylic copolymer (A) It is 0.1 parts by mass or more, more preferably 0.2 parts by mass to 3 parts by mass, and even more preferably 0.3 parts by mass to 2 parts by mass. If the content of the polysiloxane isocyanate compound is 0.1 parts by mass or more with respect to 100 parts by mass of the specific (meth)acrylic copolymer (A), there is a tendency to form an adhesive layer with excellent stain resistance.

When the adhesive composition of the present invention contains a silicone-based isocyanate compound, the mass ratio of the silicone-based isocyanate compound to the isocyanate-based cross-linking agent [polysilicon-based isocyanate compound/isocyanate-based cross-linking agent] is preferably 1/ 1~1/20, preferably 1/2~1/15, even more preferably 1/3~1/10. When the mass ratio [polysiloxane-based isocyanate compound/isocyanate-based crosslinking agent] is 1/1 or more, the specific (meth)acrylic copolymer (A) and the isocyanate-based crosslinking agent can fully react to form a crosslinked structure, Therefore, there is a tendency to impart more appropriate adhesive force to the adhesive layer. If the mass ratio [polysiloxane-based isocyanate compound/isocyanate-based crosslinking agent] is 1/20 or less, the isocyanate-based crosslinking agent contained in the adhesive composition will not become too much, and the polysiloxane-based isocyanate compound will Existing moderately, there is a tendency to form an adhesive layer with excellent stain resistance.

>Other polysiloxane compounds> The adhesive composition of the present invention may contain at least one polysiloxane compound (that is, other polysiloxane compound) other than the polysiloxane isocyanate compound within the range that does not impair the effect of the present invention. Other polysiloxane compounds can function as antistatic additives.

Other polysiloxane compounds include, for example, polysiloxane compounds having a reactive group and an alkylene oxide structure used in the preliminary reaction of a polysiloxane isocyanate compound. The specific examples of other polysiloxane compounds are the same as those of the aforementioned polysiloxane compound having a reactive group and an alkylene oxide structure, and the ideal range is also the same.

>Ionic compounds> The adhesive composition of the present invention may contain at least one ionic compound. Ionic compounds can function as antistatic agents.

The ionic compound is not particularly limited. Examples of the ionic compound include alkali metal salts and organic salts. The ionic compound, for example, considering the high ion dissociation property and the viewpoint that a small amount can easily exhibit excellent antistatic properties, it is preferably at least one selected from the group consisting of alkali metal salts and organic salts.

The alkali metal salt is not particularly limited if it is a metal salt having lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), potassium ion (K ⁺ ), rubidium ion (Rb ⁺ ), etc. as cations. An alkali metal salt should be selected by, for example, consisting of Li ^+, Na ^+, and K ⁺ in the group consisting of at least one cation selected from the group consisting of ^{Cl -, Br -, I -} , BF 4 -, PF _{^{6 -, SCN -, ClO 4}} -, CF 3 SO 3 -, (FSO 2) 2 N -, (CF 3 SO 2) 2 N -, (C 2 F 5 SO 2) 2 N -, and (CF ₃ SO ₂ ) ₃ C ^- a metal salt composed of at least one anion in the group composed of SO ₂ ) ₃ C. Among them, the alkali metal salt is preferably LiBr, LiI, LiBF ₄ , LiPF ₆ , LiSCN, LiClO ₄ , LiCF ₃ SO ₃ (so-called LiTFS), Li(FSO ₂ ) ₂ N, Li( CF ₃ SO ₂ ) ₂ N, Li(C ₂ F ₅ SO ₂ ) ₂ N, Li(CF ₃ SO ₂ ) ₃ C and other lithium salts are selected from LiClO ₄ , LiCF ₃ SO ₃ , Li(CF ₃ At least one lithium salt from the group consisting of SO ₂ ) ₂ N, Li(C ₂ F ₅ SO ₂ ) ₂ N, and Li(CF ₃ SO ₂ ) ₃ C is more preferred.

Organic salts contain organic cations and their relative ions. Organic salts include, for example, ionic solids with a melting point of 30°C or higher and ionic liquids with a melting point of less than 30°C. The organic salt is preferably an ionic solid with a melting point above 30°C. If the melting point of the organic salt is 30°C or higher, the transfer to the adherend is less and the pollution is lower, so it is ideal. Examples of organic cations include imidazolium cations, pyridinium cations, alkylpyrrolidinium cations, ammonium cations with organic groups as substituents, sulfonium cations with organic groups as substituents, phosphonium cations with organic groups as substituents, etc. . Among them, for example, from the viewpoint of antistatic properties, the organic cation is preferably a pyridinium cation or an imidazolium cation.

The anion part that becomes the counter ion of the organic cation is not particularly limited, and it may be either an inorganic anion or an organic anion. An anionic portion of the cationic organic counterions, considered excellent antistatic property viewpoint, should be fluorine atom containing fluorine anion, the anion is hexafluorophosphate (PF ₆ ^-) better.

Examples of organic salts include pyridinium salts, imidazolium salts, alkylammonium salts, alkylpyrrolidinium salts, and alkylphosphonium salts. Among them, the organic salt is preferably a pyridinium salt or an imidazolium salt, and more preferably a salt of a pyridinium cation, an imidazolium cation, and a fluorine-containing anion.

>Crosslinking catalyst> The adhesive composition of the present invention may also contain a crosslinking catalyst. The crosslinking catalyst is not particularly limited, and known ones can be used. Examples of crosslinking catalysts include organometallic compounds represented by dioctyltin dilaurate (DOTDL) and 1,3-diacetoxytetrabutyl stannoxane (1,3-diacetoxytetrabutyl stannoxane), and three Ethylenediamine and tertiary amine compounds represented by N-methyl 𠰌line.

[use] The adhesive composition of the present invention is suitable for use in a protective film (so-called optical member protective film) for protecting optical members. The adhesive composition of the present invention can form an adhesive layer with a good balance of low-speed peeling force and high-speed peeling force, fully suppressing the zipper phenomenon that may be caused by high-speed peeling, and excellent transparency, so it is suitable for optical member attachment protection The purpose of the film.

Examples of the optical member include members constituting devices such as image display devices and input devices (so-called optical devices) or members used in these devices. Specific examples of optical components include: polarizing plate, AG (Anti-Glare) polarizing plate, retardation plate including wavelength plate, 1/2, 1/4 wavelength plate, viewing angle compensation film, optical compensation film, brightness enhancement film , Light guide plate, reflective film, anti-reflection film, ITO (Indium-Tin Oxide) film and other transparent conductive films, scallops, lens sheets, scattering plates, etc. The material of the optical member can include, for example, polyester resin, acetate resin, polyether-based resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, acrylic Resins, vinyl chloride resins, ABS (Acrylonitrile Butadiene Styrene) resins, fluorine resins and other resins.

[Optical component protective film] The optical member protective film of the present invention includes a substrate and an adhesive layer provided on the substrate and formed using the adhesive composition of the present invention. That is, the protective film of the present invention is laminated with a substrate and an adhesive layer formed using the adhesive composition of the present invention. Since the protective film of the present invention is provided with the adhesive layer formed by the adhesive composition of the present invention, after being attached to the surface of the adherend, it is not easy to peel off and offset from the adherend during the period of protection It is not good, and it can be peeled off efficiently when peeling from the adherend without protection. In other words, the low-speed peel force and the high-speed peel force have a good balance. In addition, since the protective film of the present invention has an adhesive layer formed using the adhesive composition of the present invention, it is unlikely to cause a zipper phenomenon when it is peeled from an adherend at a high speed, and striped defects are unlikely to occur on the surface of the adherend. In addition, since the protective film of the present invention has an adhesive layer formed using the adhesive composition of the present invention, it has excellent transparency.

Regarding the substrate in the protective film of the present invention, if an adhesive layer can be formed on the substrate, there is no particular limitation. The base material may, for example, contain polyester resins, acetate resins (e.g., triacetyl cellulose resin), polyether ether resins, polycarbonate resins, polyamide resins, and polyimide resins. , Polyolefin resin, acrylic resin, vinyl chloride resin, ABS resin, fluorine resin and other resin films. For example, considering the viewpoint of inspection and management of optical components using perspective, the base material should preferably contain selected from polyester resins, acetate resins, polyether sulfite resins, polycarbonate resins, and polyamides. A film of at least one type of resin from the group consisting of polyimide resin, polyimide resin, polyolefin resin, and acrylic resin. In addition, for example, considering the surface protection performance, a film containing a polyester resin is preferable, and in consideration of practicality, a film containing polyethylene terephthalate (PET) is particularly preferable.

The substrate may also contain various additives such as plasticizers, colorants (such as dyes and pigments), heat stabilizers, light stabilizers, antistatic agents, flame retardants and the like. In addition, a pattern may be applied to a part or the entire base material.

The thickness of the substrate is generally 500 μm or less, preferably 300 μm or less, and more preferably 200 μm or less. The lower limit of the thickness of the base material is preferably 5 μm or more, and more preferably 10 μm or more in consideration of the strength of the protective film, for example.

An antistatic layer can also be provided on one or both sides of the substrate. In addition, the surface of the substrate on the side where the adhesive layer is provided may be subjected to surface treatments such as corona discharge treatment and plasma discharge treatment in consideration of improving the adhesion between the substrate and the adhesive layer.

The method of forming the adhesive layer is not particularly limited, and a commonly used method can be adopted. For the method of forming the adhesive layer on the substrate, for example, the following method can be adopted. The adhesive composition of the present invention is applied on a substrate in its own state or diluted with a solvent as needed, and a coating film is formed on the substrate. Then, the formed coating film is dried to remove the solvent, and then aged to form an adhesive layer on the substrate. In addition, the exposed surface of the adhesive layer can also be protected with a release film. The release film is not particularly limited as long as it can be easily released from the surface of the adhesive layer, and examples thereof include paper and resin film that have been surface-treated with a release agent on one or both sides. Examples of the resin film include polyester films represented by polyethylene terephthalate (PET) films. Examples of release agents include fluorine-based resins, paraffin wax, silicone, and long-chain alkyl compounds. The peeling film protects the surface of the adhesive layer during the period before the protective film is actually used, and is peeled off during use.

Another method of forming the adhesive layer on the substrate may be the following method, for example. The adhesive composition of the present invention is applied in its own state or in a state diluted with a solvent as required, on a release film such as paper or resin film that has been surface-treated with a release agent, and then peeled off The thin film forms a coating film. Then, the formed coating film is dried to remove the solvent. Then, the surface of the release film on the side where the adhesive layer is formed is brought into contact with the substrate and pressed, and the adhesive layer is transferred to the substrate, thereby forming an adhesive layer on the substrate. Then, aging is carried out.

The method of coating the adhesive composition on the substrate or the release film is not particularly limited. Examples include the use of a gravure roll coater, a reverse roll coater, a kiss roll coater, a dipping roll coater, and a knife coater. Well-known methods such as spraying machines, spraying machines, coating rods, and applicators. The amount of the adhesive composition applied to the substrate or the release film is appropriately set according to the thickness of the formed adhesive layer.

The thickness of the adhesive layer can be appropriately set according to the adhesive force required by the protective film, the type (such as material and shape) of the adherend, and the surface roughness of the adherend. The thickness of the adhesive layer usually falls within the range of 1 μm or more and 100 μm or less, preferably within the range of 5 μm or more and 50 μm or less, and more preferably within the range of 10 μm or more and 30 μm or less.

The method of drying the coating film formed on the substrate or the release film is not particularly limited, and examples include methods such as natural drying, heat drying, hot air drying, and vacuum drying. The drying temperature and drying time of the coating film are not particularly limited, and are appropriately set according to the thickness of the coating film, the amount of organic solvent in the coating film, and the like.

The maturation is carried out for 1 to 10 days in an environment of 23° C. and 50% RH, for example. After aging, the crosslinking reaction of the adhesive composition will end and an adhesive layer will be formed.

The adhesive force of the adhesive layer when the protective film attached to the adherend is peeled at 180° (the so-called peeling force), when the peeling speed is 0.3m/min (that is, low-speed peeling), it is preferably 0.10N /25mm or more, more preferably 0.15N/25mm or more, and even more preferably 0.20N/25mm or more. If the adhesive force during low-speed peeling (so-called low-speed peeling force) is 0.10N/25mm or more, the protective film tends to be more restrained from peeling or shifting.

The adhesive force of the adhesive layer when the protective film attached to the adherend is peeled at 180° (the so-called peeling force), when the peeling speed is 30m/min (that is, high-speed peeling), it should be less than 1.50N /25mm, less than 1.00N/25mm is better, less than 0.50N/25mm is even better. If the adhesive force during high-speed peeling (so-called high-speed peeling force) is less than 1.50N/25mm, since the protective film can be peeled from the adherend more efficiently, the workability can be improved.

In this specification, an adhesive layer with a good balance of low-speed peeling force and high-speed peeling force is evaluated based on the value (low-speed peeling force/high-speed peeling force) obtained by dividing the value of low-speed peeling force by the value of high-speed peeling force. (Low-speed peeling force/high-speed peeling force) is preferably 0.10 or more, more preferably 0.20 or more, and even more preferably 0.30 or more. [Example]

Hereinafter, the present invention will be explained more specifically using examples. The present invention is not limited to the following embodiments as long as it does not exceed the gist.

[Production of (meth)acrylic copolymer (A)] [Manufacturing Example A-1] 171.0 parts by mass of ethyl acetate and 249.0 parts by mass of tertiary butanol were put into a reaction vessel equipped with a thermometer, a stirrer, a nitrogen introduction tube, and a reflux cooler. In addition, 360.0 parts by mass of n-butyl acrylate (n-BA), 2-ethylhexyl acrylate [2EHA; other alkyl acrylate monomer (a)] 217.8 parts by mass, 4-hydroxybutyl acrylate ( 4HBA; monomer with hydroxyl group) 18.0 parts by mass and acrylic acid (AA; monomer with carboxyl group) 4.2 parts by mass were put into another container and mixed to prepare a monomer mixture. 20.0% by mass of the monomer mixture was added to the reaction vessel. Then, after replacing the air in the reaction vessel with nitrogen, 0.08 parts by mass of 2,2'-azobisisobutyronitrile [AIBN; polymerization initiator] was added, and the reaction vessel was stirred while stirring under a nitrogen atmosphere. The temperature of the contents was increased to 85°C and the initial reaction was started. While adding 80.0% by mass of the remaining monomer mixture, 88.0 parts by mass of ethyl acetate and 0.80 parts by mass of AIBN to the reaction vessel after the initial reaction was almost completed, the contents of the reaction vessel were gradually added over about 2 hours. After the addition, the reaction was allowed to react for another 2 hours to obtain the reaction product (a1). Thereafter, a solution prepared by dissolving 0.60 parts by mass of trimethyl acetic acid tertiary butyl peroxide (polymerization initiator) in 132.0 parts by mass of ethyl acetate was added dropwise to the reaction product in the reaction vessel ( In a1), after completion of the dropwise addition, the reaction was further carried out for 1.5 hours to obtain the reaction product (a2). The obtained reaction product (a2) was diluted with ethyl acetate to obtain a solution of (meth)acrylic copolymer A-1 having a solid content of 45% by mass. The term "solid content" here means a component remaining after volatile components such as a solvent are removed from the solution of the (meth)acrylic copolymer A-1. The same applies to the following solutions of (meth)acrylic copolymers A-2 to A-10.

[Manufacturing examples A-2~A-10] In Production Example A-1, the monomer composition of the (meth)acrylic copolymer (A) was changed to the monomer composition shown in Table 1, and the amount of organic solvent used and the amount of polymerization initiator used were adjusted At least one of them is used to change the weight average molecular weight (Mw) of the (meth)acrylic copolymer (A) to the weight average molecular weight (Mw) shown in Table 1. In addition, implement and manufacture In the same manner as in Example A-1, solutions of (meth)acrylic copolymers A-2 to A-10 with a solid content of 45% by mass were obtained.

(Meth) acrylic copolymer A-1~A-10 monomer composition (unit: mass %), glass transition temperature (Tg, unit: °C), and weight average molecular weight [Mw, unit: ten thousand (in the table) Marked as "×10 ⁴ ")] as shown in Table 1. The glass transition temperature (Tg) of (meth)acrylic copolymer A-1~A-10 is calculated using the same method as the glass transition temperature (Tg) of the aforementioned specific (meth)acrylic copolymer (A) Got. In addition, the weight average molecular weight (Mw) of the (meth)acrylic copolymers A-1 to A-10 is the same as the weight average molecular weight (Mw) of the aforementioned specific (meth)acrylic copolymer (A) Measured.

Among the (meth)acrylic copolymers A-1 to A-10 obtained above, the (meth)acrylic copolymers A-1 to A-7 correspond to the specific (meth)acrylic copolymers in the present invention. Copolymer (A).

[Table 1] (Meth) acrylic copolymer (A) Monomer composition [mass%] Tg [℃] Mw [×10 ⁴ ] n-BA 2EHA MA 4HBA AA A-1 60.0 36.3 - 3.0 0.7 -63.0 45.1 A-2 60.0 39.1 - 0.2 0.7 -64.1 39.9 A-3 60.0 38.8 - 0.5 0.7 -64.0 40.2 A-4 60.0 24.3 - 15.0 0.7 -57.9 47.9 A-5 60.0 22.3 - 17.0 0.7 -57.1 36.6 A-6 40.0 56.3 - 3.0 0.7 -66.8 37.7 A-7 60.0 37.0 - 3.0 - -63.8 38.5 A-8 - 96.3 - 3.0 0.7 -74.1 33.0 A-9 60.0 39.3 - - 0.7 -64.2 38.1 A-10 33.3 - 63.0 3.0 0.7 -19.7 39.2

The details of each monomer described in Table 1 are as follows. "N-BA": n-butyl acrylate >Other (meth)acrylic acid alkyl ester monomers (a)> "2EHA": 2-ethylhexyl acrylate "MA": methyl acrylate >Monomers with hydroxyl> "4HBA": 4-hydroxybutyl acrylate >Monomers with carboxyl group> "AA": Acrylic

In Table 1, "-" means the monomer in this column is not used. In Table 1, "Glass transition temperature (Tg)" is abbreviated as "Tg", and "weight average molecular weight (Mw)" is abbreviated as "Mw".

[Production of (meth)acrylic copolymer (B)] [Manufacturing Example B-1] Put 350.0 parts by mass of ethyl acetate and 150.0 parts by mass of tertiary butanol into a reaction vessel equipped with a thermometer, a stirrer, a nitrogen introduction tube, and a reflux cooler. In addition, 577.8 parts by mass of n-butyl methacrylate (n-BMA), 18.0 parts by mass of 4-hydroxybutyl acrylate (4HBA; monomer having a hydroxyl group), and 4.2 parts by mass of acrylic acid (AA; monomer having a carboxyl group) The parts by mass are put into another container and mixed to make a monomer mixture. 20.0% by mass of the monomer mixture was added to the reaction vessel. Then, after replacing the air in the reaction vessel with nitrogen, 1.80 parts by mass of 2,2'-azobisisobutyronitrile [AIBN; polymerization initiator] was added, and the reaction vessel was stirred while stirring under a nitrogen atmosphere. The temperature of the contents was increased to 85°C and the initial reaction was started. While adding the remaining monomer mixture of 80.0% by mass, 80.0 parts by mass of ethyl acetate and 8.0 parts by mass of AIBN to the reaction vessel after the initial reaction was almost completed, the contents of the reaction vessel were gradually added over about 2 hours. After the addition, the reaction was allowed to react for 1 hour to obtain the reaction product (b1). Thereafter, a solution prepared by dissolving 0.60 parts by mass of trimethyl acetic acid tertiary butyl peroxide (polymerization initiator) in 132.0 parts by mass of ethyl acetate was added dropwise to the reaction product in the reaction vessel ( In b1), after the dropwise addition is completed, the reaction is further carried out for 2 hours to obtain a reaction product (b2). The obtained reaction product (b2) was diluted with ethyl acetate to obtain a solution of (meth)acrylic copolymer B-1 having a solid content of 45% by mass. The term "solid content" here means a component remaining after volatile components such as a solvent are removed from the solution of the (meth)acrylic copolymer B-1. The same applies to the following solutions of (meth)acrylic copolymers B-2 to B-21.

[Manufacturing examples B-2~B-6, B-10~B-12, and B-15~B-21] In Production Example B-1, the monomer composition of the (meth)acrylic copolymer (B) was changed to the monomer composition shown in Table 2, and the amount of organic solvent used and the amount of polymerization initiator used were adjusted At least one of them is used to change the weight average molecular weight (Mw) of the (meth)acrylic copolymer (B) to the weight average molecular weight (Mw) shown in Table 2. In addition, implement and manufacture In Example B-1, the same operation was performed to obtain each of (meth)acrylic copolymers B-2~B-6, B-10~B-12, and B-15~B-21 with a solid content of 45% by mass Solution.

[Manufacturing examples B-7~B-9, B-13, and B-14] In Production Example B-1, at least one of the used amount of the organic solvent and the used amount of the polymerization initiator was adjusted to adjust the weight average molecular weight (Mw) of the (meth)acrylic copolymer (B) Except changing to the weight average molecular weight (Mw) shown in Table 2, the same operation as in Production Example B-1 was carried out to obtain (meth)acrylic copolymer B-7 with a solid content of 45% by mass ~B-9, B-13, and B-14 solutions.

(Meth) acrylic copolymer B-1~B-21 monomer composition (unit: mass %), glass transition temperature (Tg, unit: ℃), and weight average molecular weight [Mw, unit: ten thousand (in the table) Marked as "×10 ⁴ ")] as shown in Table 2. The glass transition temperature (Tg) of (meth)acrylic copolymer B-1~B-20 is calculated using the same method as the glass transition temperature (Tg) of the aforementioned specific (meth)acrylic copolymer (A) Got. In addition, the glass transition temperature (Tg) of (meth)acrylic copolymer B-21 was not calculated. In addition, the weight average molecular weight (Mw) of the (meth)acrylic copolymers B-1 to B-21 is the same as the weight average molecular weight (Mw) of the aforementioned specific (meth)acrylic copolymer (A) Measured.

Among the (meth)acrylic copolymers B-1 to B-21 obtained above, the (meth)acrylic copolymers B-1 to B-12 correspond to the specific (meth)acrylic copolymers in the present invention. Copolymer (B).

[Table 2] (Meth) acrylic copolymer (B) Monomer composition [mass%] Tg [℃] Mw [×10 ⁴ ] n-BMA EMA i-BMA MMA 2EHMA CHMA MePEGMA 4HBA 2HEA 2HEMA AA B-1 96.3 - - - - - - 3.0 - - 0.7 19.7 3.1 B-2 89.0 - - - - - - 0.2 - - 0.7 21.3 4.0 B-3 96.3 - - - - - - 0.5 - - 0.7 21.5 13.9 B-4 88.3 - - - - - - 15.0 - - 0.7 12.2 3.8 B-5 92.0 - - - - - - 17.0 - - 0.7 11.0 2.3 B-6 40.0 56.3 - - - - - 3.0 - - 0.7 31.1 3.0 B-7 96.3 - - - - - - 3.0 - - 0.7 19.7 1.1 B-8 96.3 - - - - - - 3.0 - - 0.7 19.7 13.9 B-9 96.3 - - - - - - 3.0 - - 0.7 19.7 18.2 B-10 96.3 - - - - - - - 3.0 - 0.7 20.4 2.9 B-11 96.3 - - - - - - - - 3.0 0.7 22.6 3.2 B-12 97.0 - - - - - - 3.0 - - - 19.1 2.4 B-13 96.3 - - - - - - 3.0 - - 0.7 19.7 25.4 B-14 96.3 - - - - - - 3.0 - - 0.7 19.7 0.5 B-15 - 96.3 - - - - - 3.0 - - 0.7 39.7 5.8 B-16 99.3 - - - - - - - - - 0.7 21.7 3.1 B-17 - - 40.0 - - 60.0 - - - - - 59.0 0.4 B-18 - - - 95.0 - - - - - 5.0 - 96.0 2.0 B-19 46.3 - - 50.0 - - - 3.0 - - 0.7 55.4 2.9 B-20 21.3 - - - 75.0 - - 3.0 - - 0.7 -3.9 2.8 B-21 89.7 - - - - - 10.0 - - - 0.3 - 0.7

The details of each monomer described in Table 2 are as follows. "N-BMA": n-butyl methacrylate >Other (meth)acrylate alkyl ester monomers (b)> "EMA": ethyl methacrylate "I-BMA": Isobutyl methacrylate "MMA": methyl methacrylate "2EHMA": 2-ethylhexyl methacrylate "CHMA": Cyclohexyl methacrylate >Other monomers> "MePEGMA": Methoxy polyethylene glycol methacrylate (average number of moles added to alkylene oxide: 23) >Monomers with hydroxyl> "4HBA": 4-hydroxybutyl acrylate "2HEA": 2-hydroxyethyl acrylate "2HEMA": 2-hydroxyethyl methacrylate >Monomers with carboxyl group> "AA": Acrylic

In Table 2, the "-" described in the column of monomer composition means a monomer for which the column is not used. In Table 2, "Glass transition temperature (Tg)" is abbreviated as "Tg", and "weight average molecular weight (Mw)" is abbreviated as "Mw".

[Production of polysiloxane isocyanate compound] TAKENATE (registered trademark) 500 [trade name, xylylene diisocyanate (XDI), manufactured by Mitsui Chemicals Co., Ltd.] 118.0 parts by mass and SH-3773M [trade name, polyether modified polysiloxane compound, Toray Dow Corning (Stock) 82.0 parts by mass was fed into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen introduction tube, a reflux cooler, and a dropping funnel. After replacing the air in the flask with nitrogen, the internal temperature was raised To 50°C. While maintaining the internal temperature at 50°C, the contents in the flask were stirred for 6 hours to obtain a polysiloxane-based isocyanate compound.

[Preparation of adhesive composition] [Example 1] 222.2 parts by mass of a solution of (meth)acrylic copolymer A-1 (100 parts by mass of solid content) and (meth)acrylic copolymer B-1 66.6 parts by mass (solid content of 30 parts by mass), SH-3773M [trade name, polyether modified polysiloxane compound, manufactured by Toray Dow Corning Co., Ltd.] 0.30 parts by mass, LiTFS [LiCF ₃ SO ₃ , Morita [Chemical Industry Co., Ltd.] 0.25 parts by mass was fed into a four-necked flask equipped with a stirring blade, a thermometer, a cooler, and a dropping funnel, and stirred for 4 hours while maintaining the liquid temperature in the flask at around 25°C. Then, add SUMIDUR (registered trademark) N-3300 as an isocyanate-based crosslinking agent in the flask [trade name, diluent of the trimer of hexamethylene diisocyanate (HMDI), manufactured by Sumika Covestro Urethane (Stock)] 12.0 parts by mass (solid content is 3.00 parts by mass), fully stirred to obtain an adhesive composition.

[Examples 2~18] In Examples 2 to 18, the composition of the adhesive composition was changed to the composition shown in Table 3. Except that, the same operation as in Example 1 was performed to obtain the adhesive composition.

[Examples 19~34] In Examples 19 to 34, except that the composition of the adhesive composition was changed to the composition shown in Table 4, the same operation as in Example 1 was performed to obtain the adhesive composition.

[Comparative Examples 1~16] In Comparative Examples 1-16, the composition of the adhesive composition was changed to the composition shown in Table 5. Except that, the same operation as in Example 1 was performed to obtain the adhesive composition.

[table 3] Composition of adhesive composition (Meth) acrylic copolymer (A) (Meth) acrylic copolymer (B) Isocyanate-based crosslinking agent Other ingredients SH-3773M LiTFS DOTDL species Blending amount [parts by mass] species Blending amount [parts by mass] species Blending amount [parts by mass] Blending amount [parts by mass] Blending amount [parts by mass] Blending amount [parts by mass] Example 1 A-1 100 B-1 30 N-3300 3.00 0.30 0.25 - Example 2 A-2 100 B-1 30 N-3300 3.00 0.30 0.25 - Example 3 A-3 100 B-1 30 N-3300 3.00 0.30 0.25 - Example 4 A-4 100 B-1 30 N-3300 3.00 0.30 0.25 - Example 5 A-5 100 B-1 30 N-3300 3.00 0.30 0.25 - Example 6 A-6 100 B-1 30 N-3300 3.00 0.30 0.25 - Example 7 A-7 100 B-1 30 N-3300 3.00 0.30 0.25 0.02 Example 8 A-1 100 B-2 30 N-3300 3.00 0.30 0.25 - Example 9 A-1 100 B-3 30 N-3300 3.00 0.30 0.25 - Example 10 A-1 100 B-4 30 N-3300 3.00 0.30 0.25 - Example 11 A-1 100 B-5 30 N-3300 3.00 0.30 0.25 - Example 12 A-1 100 B-6 30 N-3300 3.00 0.30 0.25 - Example 13 A-1 100 B-7 30 N-3300 3.00 0.30 0.25 - Example 14 A-1 100 B-8 10 N-3300 3.00 0.30 0.25 - Example 15 A-1 100 B-9 30 N-3300 3.00 0.30 0.25 - Example 16 A-1 100 B-10 30 N-3300 6.00 0.30 0.25 - Example 17 A-1 100 B-11 30 N-3300 3.00 0.30 0.25 - Example 18 A-1 100 B-12 30 N-3300 6.00 0.30 0.25 0.02

[Table 4] Composition of adhesive composition (Meth) acrylic copolymer (A) (Meth) acrylic copolymer (B) Isocyanate-based crosslinking agent Other ingredients SH-3773M LiTFS Polysiloxane isocyanate compound ALUMICHELATE species Blending amount [parts by mass] species Blending amount [parts by mass] species Blending amount [parts by mass] Blending amount [parts by mass] Blending amount [parts by mass] Blending amount [parts by mass] Blending amount [parts by mass] Example 19 A-1 100 B-1 1 N-3300 3.00 0.30 0.25 - - Example 20 A-1 100 B-1 5 N-3300 1.50 0.30 0.25 - - Example 21 A-1 100 B-1 10 N-3300 3.00 0.30 0.25 - - Example 22 A-1 100 B-1 60 N-3300 3.00 0.30 0.25 - - Example 23 A-1 100 B-1 70 N-3300 3.00 0.30 0.25 - - Example 24 A-1 100 B-1 30 N-3300 0.50 0.30 0.25 - - Example 25 A-1 100 B-1 30 N-3300 10.00 0.30 0.25 - - Example 26 A-1 100 B-1 30 L-45E 3.00 0.30 0.25 - - Example 27 A-1 100 B-1 30 N-3400 3.00 0.30 0.25 - - Example 28 A-1 100 B-1 30 D-120 3.00 0.30 0.25 - - Example 29 A-1 100 B-1 30 N-3300 /N-3400 2.97 /0.03 0.30 0.25 - - Example 30 A-1 100 B-1 30 N-3300 3.00 0.30 0.25 - 0.10 Example 31 A-1 100 B-1 30 N-3300 6.00 - - - - Example 32 A-1 100 B-1 30 N-3300 6.00 - 3.00 - - Example 33 A-1 100 B-1 30 N-3300 3.00 0.30 - - - Example 34 A-1 100 B-1 30 N-3300 6.00 - 0.25 0.45 -

[table 5] Composition of adhesive composition (Meth) acrylic copolymer (A) (Meth) acrylic copolymer (B) Isocyanate-based crosslinking agent Other ingredients SH-3773M LiTFS TETRAD-X species Blending amount [parts by mass] species Blending amount [parts by mass] species Blending amount [parts by mass] Blending amount [parts by mass] Blending amount [parts by mass] Blending amount [parts by mass] Comparative example 1 A-1 100 - - N-3300 3.00 0.30 0.25 - Comparative example 2 A-8 100 B-1 30 N-3300 3.00 0.30 0.25 - Comparative example 3 A-9 100 B-1 30 N-3300 3.00 0.30 0.25 - Comparative example 4 A-10 100 B-1 30 N-3300 3.00 0.30 0.25 - Comparative example 5 A-1 100 B-13 30 N-3300 3.00 0.30 0.25 - Comparative example 6 A-1 100 B-14 30 N-3300 3.00 0.30 0.25 - Comparative example 7 A-1 100 B-15 30 N-3300 3.00 0.30 0.25 - Comparative example 8 A-1 100 B-16 30 N-3300 3.00 0.30 0.25 - Comparative example 9 A-1 100 B-17 1 N-3300 3.00 0.30 0.25 - Comparative example 10 A-1 100 B-18 5 N-3300 3.00 0.30 0.25 - Comparative example 11 A-1 100 B-19 30 N-3300 3.00 0.30 0.25 - Comparative example 12 A-1 100 B-20 30 N-3300 3.00 0.30 0.25 - Comparative example 13 A-1 100 B-1 80 N-3300 3.00 0.30 0.25 - Comparative example 14 A-1 100 B-1 0.5 N-3300 3.00 0.30 0.25 - Comparative example 15 A-1 100 B-1 30 - - 0.30 0.25 3.00 Comparative example 16 A-1 100 B-21 2 N-3300 3.00 0.30 0.25 -

In Tables 3 to 5, "-" means that the ingredient is not included.

The details of the ingredients listed in Tables 3 to 5 are as follows. >Isocyanate-based crosslinking agent> "N-3300" [Trade name: SUMIDUR (registered trademark) N-3300, manufactured by Sumika Covestro Urethane (Stock)]: 4-fold dilution of the trimer of hexamethylene diisocyanate (HMDI), solid content: 25 quality% "L-45E" [trade name: CORONATE (registered trademark) L-45E, manufactured by Tosoh Corporation]: adduct of toluene diisocyanate (TDI) and trimethylolpropane (TMP), solid content: 45 quality% "N-3400" [Trade name: DESMODUR (registered trademark) N-3400, manufactured by Sumika Covestro Urethane (Stock)]: 4-fold dilution of the dimer of hexamethylene diisocyanate (HMDI), solid content: 25 quality% "D-120" [trade name: TAKENATE (registered trademark) D-120, manufactured by Mitsui Chemicals Co., Ltd.]: adduct of xylylene diisocyanate (XDI) and trimethylolpropane (TMP), solid content ：75% by mass

>Other ingredients>"SH-3773M" [trade name, manufactured by Toray Dow Corning Co., Ltd.]: polyether modified polysiloxane compound (having a hydroxyl group at the end of the polyalkyleneoxy group as a reactive group), other poly Siloxane "LiTFS" [manufactured by Morita Chemical Industry Co., Ltd.]: lithium trifluoromethanesulfonate [LiCF ₃ SO ₃ ], ionic compound "DOTDL": dioctyltin dilaurate, cross-linking catalyst "ALUMICHELATE "[Kawaken Fine Chemicals Co., Ltd.]: Ginseng acetone aluminum, metal chelate crosslinking agent "TETRAD-X" [Trade name: TETRAD (registered trademark)-X, manufactured by Mitsubishi Gas Chemical Co., Ltd.] ：Epoxy crosslinking agent

[Evaluation] Using the adhesive composition prepared above, the following evaluation was performed. The results are shown in Tables 6-8.

1. Peeling force>Production of protective film for peeling force evaluation> Polyethylene terephthalate (PET) film as substrate [trade name: TEIJIN (registered trademark) TETORON (registered trademark) film, model: G2 , Thickness: 38μm, the adhesive composition is coated on Teijin Film Solutions (manufactured by Teijin Film Solutions) so that the coating weight after drying becomes 15g/m ² , and a coating film is formed. Then, the formed coating film was dried at 100° C. for 60 seconds using a hot air circulation type dryer. Then, the exposed surface of the dried adhesive film is superimposed on a release film that has been surface-treated with a silicone release agent [trade name: FILMBYNA (registered trademark) 100E-0010N023, thickness: 100 μm, Fujimori Industry Co., Ltd.)制]The surface treatment surface is made into a laminate. After the laminate was crimped and bonded by a pressure nip roller pair, it was aged for 96 hours under an ambient temperature of 23°C and 50% RH to allow the crosslinking reaction to proceed, thereby obtaining a substrate/adhesive layer A protective film for evaluating the peel strength of the laminated structure of the release film.

(1) Low speed peeling force The protective film for peeling force evaluation prepared above was cut into a size of 25 mm×150 mm to prepare a protective film sheet for peeling force evaluation. Then, the peeling film was peeled from the prepared protective film sheet for peeling force evaluation, and the surface of the adhesive layer exposed by the peeling was laminated on a polyethylene terephthalate (PET) film [trade name: After the surface of COSMOSHINE (registered trademark) A4300, thickness: 300μm, manufactured by Toyobo Co., Ltd., it was crimped using a desktop laminator to prepare a test sample. The test sample was placed in an ambient temperature of 23°C and 50%RH for 24 hours. Then, using a single-column material testing machine [model: STA-1225, manufactured by A&D (stock)] as a measuring device, under the conditions of an ambient temperature of 23°C, 50%RH, and a peeling speed of 0.3m/min, The peeling force (unit: N/25mm) of the PET film when the protective film sheet (adhesive layer/base material) for peeling force evaluation is peeled at 180° along the long side (150 mm) direction. Then, the low-speed peel force was evaluated according to the following evaluation criteria. If the evaluation result is "AA", "A", or "B", it is determined that the low-speed peel strength is excellent.

-Evaluation criteria- AA: Peeling force is 0.20N/25mm or more. A: The peeling force is 0.15N/25mm or more and less than 0.20N/25mm. B: The peeling force is 0.10 N/25mm or more and less than 0.15 N/25mm. C: The peeling force is less than 0.10 N/25mm.

(2) High-speed peeling force Obtain test samples using the same procedure as in "(1) Low-speed peel force" above. The test sample was placed in an ambient temperature of 23°C and 50%RH for 24 hours. Then, using a peeling tester [model: horizontal TE-720, manufactured by TESTER SANGYO (stock)] as a measuring device, under the conditions of an ambient temperature of 23°C, 50%RH, and a peeling speed of 30m/min, the measurement was made from PET The peeling force (unit: N/25mm) when the film is peeled 180° from the protective film sheet (adhesive layer/base material) for peeling force evaluation in the long side (150 mm) direction. Then, the high-speed peel force was evaluated according to the following evaluation criteria. If the evaluation result is "AA", "A", or "B", it is judged that the high-speed peel strength is excellent.

-Evaluation criteria- AA: Peeling force is less than 0.50N/25mm. A: The peeling force is 0.50 N/25mm or more and less than 1.00 N/25mm. B: The peeling force is 1.00 N/25mm or more and less than 1.50 N/25mm. C: The peeling force is 1.50N/25mm or more.

(3) Balance of low-speed peeling force and high-speed peeling force Evaluate the balance of low-speed peeling force and high-speed peeling force based on the value of low-speed peeling force measured in the above "(1) Low-speed peeling force" and the value of high-speed peeling force measured in "(2) High-speed peeling force" above. Specifically, based on the value obtained by dividing the value of the low-speed peeling force by the value of the high-speed peeling force, and rounding the third digit below the decimal point, the following evaluation criteria are used to evaluate the low-speed peeling force and the high-speed peeling force. balance. If the evaluation result is "AA", "A", or "B", it is determined that the low-speed peel force and the high-speed peel force have a good balance.

-Evaluation criteria- AA: "Low-speed peeling force/high-speed peeling force" is 0.30 or more. A: "Low-speed peeling force/high-speed peeling force" is 0.20 or more and less than 0.30. B: "Low-speed peeling force/high-speed peeling force" is 0.10 or more and less than 0.20. C: "Low-speed peeling force/high-speed peeling force" is less than 0.10.

2. Inhibition of zipper phenomenon In the above-mentioned "(2) High-speed peeling force", it was confirmed whether or not there is a zipper sound when peeling the protective film sheet (adhesive layer/base material) for peeling force evaluation from the PET film and its degree. Then, the suppression of the zipper phenomenon was evaluated according to the following evaluation criteria. If the evaluation result is "AA", "A", or "B", it is determined that the zipper phenomenon that may be caused when peeling off at high speed is sufficiently suppressed.

-Evaluation criteria- AA: No sound can be heard at all. A: I hear the sound vaguely. B: A sound is heard slightly. C: A louder sound is heard.

3. Transparency>Production of protective film for transparency evaluation> Polyethylene terephthalate (PET) film as a substrate [trade name: COMOSHINE (registered trademark) A4100, thickness: 100μm, Toyobo Co., Ltd.) Preparation] Coat the adhesive composition to make the coating amount after drying 40g/m ² , and form a coating film. Then, the formed coating film was dried at 100° C. for 60 seconds using a hot air circulation dryer to form an adhesive film on the PET film. Then, the exposed surface of the adhesive film formed on the PET film was laminated on a release film that has been surface-treated with a silicone release agent [trade name: FILMBYNA (registered trademark) 100E-0010N023, thickness: 100 μm, Fujimori Industrial (Stock) Co., Ltd.] surface treatment surface, made into a laminate. After the laminate was crimped and bonded by a pressure nip roller pair, it was aged for 96 hours under an ambient temperature of 23°C and 50% RH to allow the crosslinking reaction to proceed, thereby obtaining a substrate/adhesive layer A protective film for evaluating the transparency of the laminated structure of the release film.

The protective film for transparency evaluation prepared above was cut into a size of 25 mm×150 mm to prepare a protective film sheet for transparency evaluation. The release film was peeled from the protective film sheet for transparency evaluation, and the adhesive layer was exposed, and it used for the measurement of haze. The haze was measured using a haze meter (model: NDH 5000SP) manufactured by Nippon Denshoku Industries Co., Ltd. Based on the measured haze value (unit: %), the transparency was evaluated according to the following evaluation criteria. If the evaluation result is "AA", "A", or "B", it is judged that the transparency is excellent.

-Evaluation criteria- AA: The haze value is less than 1.0%. A: The haze value is 1.0% or more and less than 1.5%. B: The haze value is 1.5% or more and less than 2.0%. C: The haze value is 2.0% or more.

[Table 6] Evaluation Peel force Suppression of zipper phenomenon [Peeling speed: 30m/min] Transparency Low speed [Peeling speed: 0.3m/min High speed [Peeling speed: 30m/min] Balance of low-speed peeling force and high-speed peeling force [low-speed peeling force/high-speed peeling force] Measured value [N/25mm] Evaluation results Measured value [N/25mm] Evaluation results Calculated Evaluation results Evaluation results Haze value [%] Evaluation results Example 1 0.21 AA 0.49 AA 0.43 AA AA 0.71 AA Example 2 0.22 AA 1.39 B 0.16 B AA 0.72 AA Example 3 0.19 A 1.11 B 0.17 B AA 0.81 AA Example 4 0.12 B 0.49 AA 0.24 A A 0.92 AA Example 5 0.11 B 0.41 AA 0.27 A B 1.10 A Example 6 0.11 B 0.56 A 0.20 A A 1.21 A Example 7 0.26 AA 0.69 A 0.37 AA AA 1.03 A Example 8 0.20 AA 1.34 B 0.15 B AA 0.75 AA Example 9 0.21 AA 1.22 B 0.17 B AA 0.71 AA Example 10 0.15 A 0.48 AA 0.31 AA A 0.86 AA Example 11 0.12 B 0.47 AA 0.26 A A 0.94 AA Example 12 0.23 AA 0.55 A 0.42 AA A 1.61 B Example 13 0.13 B 1.23 B 0.11 B A 0.73 AA Example 14 0.23 AA 0.41 AA 0.56 AA A 1.35 A Example 15 0.22 AA 0.35 AA 0.63 AA B 1.89 B Example 16 0.18 A 0.89 A 0.20 A A 0.98 AA Example 17 0.16 A 0.69 A 0.23 A A 0.82 AA Example 18 0.21 AA 0.98 A 0.21 A AA 0.78 AA

[Table 7] Evaluation Peel force Suppression of zipper phenomenon [Peeling speed: 30m/min] Transparency Low speed [Peeling speed: 0.3m/min High speed [Peeling speed: 30m/min] Balance of low-speed peeling force and high-speed peeling force [low-speed peeling force/high-speed peeling force] Measured value [N/25mm] Evaluation results Measured value [N/25mm] Evaluation results Calculated Evaluation results Evaluation results Haze value [%] Evaluation results Example 19 0.10 B 0.93 A 0.11 B AA 0.73 AA Example 20 0.12 B 0.71 A 0.17 B AA 0.71 AA Example 21 0.15 A 0.64 A 0.23 A AA 0.76 AA Example 22 0.22 AA 0.37 AA 0.60 AA A 1.42 A Example 23 0.22 AA 0.31 AA 0.72 AA B 1.67 B Example 24 0.45 AA 1.38 B 0.33 AA AA 0.80 AA Example 25 0.11 B 0.28 AA 0.39 AA B 1.09 A Example 26 0.22 AA 1.10 B 0.20 A AA 0.89 AA Example 27 0.20 AA 0.46 AA 0.43 AA AA 0.88 AA Example 28 0.24 AA 0.93 A 0.26 A AA 0.81 AA Example 29 0.16 A 0.52 A 0.31 AA AA 0.79 AA Example 30 0.17 A 0.72 A 0.24 A A 0.78 AA Example 31 0.19 A 1.47 B 0.13 B A 0.71 AA Example 32 0.19 A 1.24 B 0.15 B A 0.79 AA Example 33 0.23 AA 0.90 A 0.26 A A 0.80 AA Example 34 0.32 AA 1.17 B 0.27 A A 0.75 AA

[Table 8] Evaluation Peel force Suppression of zipper phenomenon [Peeling speed: 30m/min] Transparency Low speed [Peeling speed: 0.3m/min High speed [Peeling speed: 30m/min] Balance of low-speed peeling force and high-speed peeling force [low-speed peeling force/high-speed peeling force] Measured value [N/25mm] Evaluation results Measured value [N/25mm] Evaluation results Calculated Evaluation results Evaluation results Haze value [%] Evaluation results Comparative example 1 0.08 C 1.80 C 0.04 C AA 0.69 AA Comparative example 2 0.09 C 0.49 AA 0.18 B AA 5.04 C Comparative example 3 0.19 A 2.23 C 0.09 C AA 0.85 AA Comparative example 4 0.26 AA 2.75 C 0.09 C B 1.89 B Comparative example 5 0.22 AA 0.49 AA 0.45 AA C 2.31 C Comparative example 6 0.09 C 1.65 C 0.05 C AA 0.81 AA Comparative example 7 0.16 A 0.43 AA 0.37 AA B 3.11 C Comparative example 8 0.16 A 1.78 C 0.09 C AA 0.92 AA Comparative example 9 0.23 AA 0.89 A 0.26 A C 2.34 C Comparative example 10 0.25 AA 0.73 A 0.34 AA C 2.70 C Comparative example 11 0.32 AA 0.47 AA 0.68 AA C 2.94 C Comparative example 12 0.08 C 1.72 C 0.05 C AA 1.23 A Comparative example 13 0.21 AA 0.49 AA 0.43 AA C 2.17 C Comparative example 14 0.09 C 1.53 C 0.06 C AA 0.70 AA Comparative example 15 1.10 AA 1.21 B 0.91 AA C 1.65 B Comparative example 16 0.23 AA 4.50 C 0.05 C AA 0.81 AA

As shown in Table 6 and Table 7, it is confirmed that the glass transition temperature is -40°C or less and the weight average molecular weight is more than 200,000 and the structural unit containing the structural unit derived from n-butyl acrylate and the monomer having a hydroxyl group is used. The (meth)acrylic copolymer (A) [that is, the specific (meth)acrylic copolymer (A)] in the range of 2 million or less, containing the structural unit derived from n-butyl methacrylate and the The specific (meth)acrylic copolymer (B) whose glass transition temperature falls within the range of 0°C or more and 45°C and the weight average molecular weight falls within the range of 10,000 or more and 200,000 or less [also That is, the specific (meth)acrylic copolymer (B)] and the isocyanate crosslinking agent, the content of the specific (meth)acrylic copolymer (B) is relative to the specific (meth)acrylic copolymer (A) 100 parts by mass, the adhesive layers formed by the adhesive compositions of Examples 1 to 34, which fall within the range of 1 part by mass to 70 parts by mass, all have a good balance of low-speed peeling force and high-speed peeling force. And it can fully suppress the zipper phenomenon that may be caused when peeling at high speed, and has excellent transparency.

On the other hand, as shown in Table 8, it was confirmed that the adhesive layer formed by the adhesive composition of Comparative Example 1 that does not contain the specific (meth)acrylic copolymer (B) has significantly lower low-speed peel strength. And the high-speed peeling force is obviously higher, and the balance between the low-speed peeling force and the high-speed peeling force is not good. It was confirmed that the adhesive layer formed by the adhesive composition of Comparative Example 2 in which the (meth)acrylic copolymer (A) does not contain structural units derived from n-butyl acrylate has a significantly high haze and poor transparency. It was confirmed that the adhesive layer formed by the adhesive composition of Comparative Example 3 in which the (meth)acrylic copolymer (A) does not contain a structural unit derived from a monomer having a hydroxyl group has significantly higher high-speed peeling force and low-speed peeling The balance between force and high-speed peel force is poor. It is confirmed that the adhesive layer formed by the adhesive composition of Comparative Example 4 whose glass transition temperature (Tg) of the (meth)acrylic copolymer (A) exceeds -40°C has significantly higher high-speed peeling force and low-speed peeling The balance between force and high-speed peel force is poor.

It was confirmed that the adhesive layer formed by the adhesive composition of Comparative Example 5 in which the weight average molecular weight of the (meth)acrylic copolymer (B) exceeds 200,000, cannot sufficiently suppress the zipper phenomenon that may be caused when peeling at high speed. In addition, it was confirmed that the adhesive layer formed using the adhesive composition of Comparative Example 5 had significantly higher haze and poor transparency. It was confirmed that the adhesive layer formed by the adhesive composition of Comparative Example 6 in which the weight average molecular weight of the (meth)acrylic copolymer (B) was less than 10,000 had significantly lower low-speed peeling force and obvious high-speed peeling force Higher, poor balance between low-speed peeling force and high-speed peeling force. It is confirmed that the adhesive layer formed by the adhesive composition of Comparative Example 7 in which the (meth)acrylic copolymer (B) does not contain structural units derived from n-butyl methacrylate has significantly higher haze and transparency bad. It is confirmed that the adhesive layer formed by the adhesive composition of Comparative Example 8 in which the (meth)acrylic copolymer (B) does not contain a structural unit derived from a monomer having a hydroxyl group has significantly higher high-speed peeling force and low-speed peeling The balance between force and high-speed peel force is poor.

It was confirmed that the use of (meth)acrylic systems that do not contain structural units derived from n-butyl methacrylate and monomers having hydroxyl groups, have a glass transition temperature (Tg) exceeding 45°C and a weight average molecular weight of less than 10,000 The adhesive layer formed by the adhesive composition of Comparative Example 9 of the copolymer (B) cannot sufficiently suppress the zipper phenomenon that may be caused when peeling off at high speed. In addition, it was confirmed that the adhesive layer formed using the adhesive composition of Comparative Example 9 had a significantly higher haze and poor transparency. The adhesion formed by the adhesive composition of Comparative Example 10 containing a (meth)acrylic copolymer (B) with no structural unit derived from n-butyl methacrylate and a glass transition temperature (Tg) exceeding 45°C was confirmed The agent layer cannot sufficiently suppress the zipper phenomenon that may be caused when peeling off at high speed. In addition, it was confirmed that the adhesive layer formed using the adhesive composition of Comparative Example 10 had a significantly high haze and poor transparency. It was confirmed that the adhesive layer formed by the adhesive composition of Comparative Example 11 in which the glass transition temperature (Tg) of the (meth)acrylic copolymer (B) exceeds 45°C cannot sufficiently suppress the possibility of peeling at high speed Zipper phenomenon. In addition, it was confirmed that the adhesive layer formed using the adhesive composition of Comparative Example 11 had a significantly higher haze and poor transparency. It was confirmed that the adhesive layer formed by the adhesive composition of Comparative Example 12 in which the glass transition temperature (Tg) of the (meth)acrylic copolymer (B) was less than 0°C had significantly lower low-speed peeling force and high-speed The peeling force is significantly higher, and the balance between the low-speed peeling force and the high-speed peeling force is poor.

It was confirmed that the content of the specific (meth)acrylic copolymer (B) is more than 70 parts by mass relative to 100 parts by mass of the specific (meth)acrylic copolymer (A), which is formed by the adhesive composition of Comparative Example 13 The adhesive layer cannot sufficiently suppress the zipper phenomenon that may be caused when peeling off at a high speed. In addition, it was confirmed that the adhesive layer formed using the adhesive composition of Comparative Example 13 had a significantly higher haze and poor transparency. It is confirmed that the content of the specific (meth)acrylic copolymer (B) is less than 1 part by mass relative to 100 parts by mass of the specific (meth)acrylic copolymer (A), which is formed by the adhesive composition of Comparative Example 14 For the adhesive layer, the low-speed peeling force is significantly lower, and the high-speed peeling force is significantly higher, and the balance between the low-speed peeling force and the high-speed peeling force is not good. It was confirmed that the adhesive layer formed by the adhesive composition of Comparative Example 15 that does not contain an isocyanate-based crosslinking agent cannot sufficiently suppress the zipper phenomenon that may be caused when peeling at high speed. It was confirmed that the adhesive layer formed by the adhesive composition of Comparative Example 16 in which the specific (meth)acrylic copolymer (B) contains an alkylene oxide chain and does not contain a structural unit derived from a monomer having a hydroxyl group, peels off at a high speed The force is obviously higher, and the balance between low-speed peeling force and high-speed peeling force is not good.

Claims (10)

An adhesive composition for a protective film of an optical component, which contains: The (meth)acrylic copolymer (A) contains a structural unit derived from n-butyl acrylate and a structural unit derived from a monomer having a hydroxyl group, and has a glass transition temperature of -40°C or less and a weight average molecular weight of more than 200,000 and The range below 2 million, The (meth)acrylic copolymer (B) contains a structural unit derived from n-butyl methacrylate and a structural unit derived from a monomer having a hydroxyl group. The glass transition temperature falls within the range of 0°C to 45°C and the weight The average molecular weight falls within the range of more than 10,000 and less than 200,000, and Isocyanate series crosslinking agent; The content of the (meth)acrylic copolymer (B) falls within the range of 1 part by mass or more and 70 parts by mass or less with respect to 100 parts by mass of the (meth)acrylic copolymer (A). The adhesive composition for an optical member protective film of claim 1, wherein the glass transition temperature of the (meth)acrylic copolymer (A) falls within the range of -70°C or more and -40°C or less. The adhesive composition for an optical member protective film according to claim 1 or 2, wherein the content of the n-butyl methacrylate-derived structural unit in the (meth)acrylic copolymer (B) is relative to the All the structural units of the (meth)acrylic copolymer (B) are 50% by mass or more. The adhesive composition for an optical member protective film of claim 1 or 2, wherein the content of the structural unit derived from n-butyl acrylate in the (meth)acrylic copolymer (A) is relative to the (former) All the structural units of the base) acrylic copolymer (A) are 50% by mass or more. The adhesive composition for an optical member protective film of claim 1 or 2, wherein the (meth)acrylic copolymer (A) has a content rate of the structural unit derived from the monomer having a hydroxyl group relative to the ( All the structural units of the meth)acrylic copolymer (A) fall within the range of 0.7% by mass or more and 15% by mass or less. The adhesive composition for an optical member protective film of claim 1 or 2, wherein the (meth)acrylic copolymer (B) has a content rate of the structural unit derived from the monomer having a hydroxyl group relative to the ( All the structural units of the meth)acrylic copolymer (B) fall within the range of 0.7% by mass or more and 15% by mass or less. The adhesive composition for an optical member protective film of claim 1 or 2, wherein the content of the (meth)acrylic copolymer (B) is relative to 100 parts by mass of the (meth)acrylic copolymer (A) , Falls within the range of 3 parts by mass or more and 60 parts by mass or less. The adhesive composition for an optical member protective film of claim 1 or 2, wherein the weight average molecular weight of the (meth)acrylic copolymer (B) falls within the range of 10,000 or more and 150,000 or less. The adhesive composition for an optical member protective film of claim 1 or 2, wherein the isocyanate-based crosslinking agent is hexamethylene diisocyanate. A protective film for optical components, comprising: Substrate, and The adhesive layer is provided on the substrate and is formed by using the adhesive composition for an optical member protective film according to any one of claims 1 to 9.