WO2014020821A1

WO2014020821A1 - Adhesive composition, adhesive layer, adhesive sheet, surface protection sheet, optical surface protection sheet, and optical film with surface protection sheet

Info

Publication number: WO2014020821A1
Application number: PCT/JP2013/003985
Authority: WO
Inventors: 昌之岡本; 真人山形; 清恵重富; 菅野　亮
Original assignee: 日東電工株式会社
Priority date: 2012-07-31
Filing date: 2013-06-26
Publication date: 2014-02-06
Also published as: JP5430722B2; JP2014028906A; TW201408743A

Abstract

This adhesive composition is characterized by containing: 100 parts by mass of a polymer (A) having a glass transition temperature of less than 0°C; and 0.05-20 parts by mass of a (meth)acrylate polymer (B) having a weight average molecular weight of at least 1000 and less than 30,000 and containing as monomer units a (meth)acrylate monomer having a alicyclic structure represented by general formula (1), a monomer having a polyoxyalkylene backbone, and a monomer having a polyorganosiloxane backbone. In particular, the present invention is used as a surface protection film used with the objective of protecting the surface of an optical member such as a polarizing plate, a wave plate, an optical compensation film, a reflective sheet, or the like. Formula (1) is CH₂=C(R¹)COOR² (in formula (1), R¹ is a hydrogen atom or a methyl group, and R² is an alicyclic hydrocarbon group having an alicyclic structure).

Description

Adhesive composition, adhesive layer, adhesive sheet, surface protective sheet, optical surface protective sheet, and optical film with surface protective sheet

The present invention relates to an adhesive composition, and an adhesive layer and an adhesive sheet having the adhesive composition. The pressure-sensitive adhesive sheet of the present invention can be used as a surface protective sheet that protects the surface of the adherend when it is adhered to the adherend and can be easily removed after use, for example. In particular, it can be used as an optical surface protective sheet used for the purpose of protecting the surface of an optical member such as a polarizing plate, a wave plate, an optical compensation film, and a reflective sheet, and an optical surface protective sheet is used for the optical member. It can also be used as an optical film with an attached surface protective sheet.

There is known an adhesive sheet for re-peeling that is adhered to an adherend and peeled after a certain period of time. For example, a surface protective sheet is generally used for the purpose of sticking to a protected body via an adhesive applied to the surface protective sheet side, and preventing scratches and dirt generated during processing and transportation of the protected body. And when a surface protection sheet becomes unnecessary, it peels and is removed (re-peeling). Stainless steel products, plastic products, glass plates, and the like are known as objects to be protected. In recent years, surface protective sheets have been used to prevent scratches and dirt on optical members (optical films) to be bonded to liquid crystal cells of liquid crystal displays. (Optical surface protective sheet) is bonded.

As described above, the surface protective sheet is peeled off when it is no longer needed, but it is often peeled off at a relatively high speed from the viewpoint of work efficiency. For this reason, when the adhesive force at the time of high-speed peeling is high, work efficiency is inferior, and there is a problem that a protected object such as an optical member or glass is damaged at the time of peeling. On the other hand, if the adhesive force at the time of high-speed peeling is to be made sufficiently small, the adhesive force at the time of low-speed peeling is also lowered, which may cause problems such as floating or peeling after the punching process of the protected body or the end face polishing process. In addition, when using a surface protection sheet as a surface protection application of an optical member, the adherend inspection process may be performed with the surface protection sheet being bonded, and the surface protection sheet itself is required to have high transparency. It was.

In response to such requirements, the glass transition temperature is constant as a surface protection sheet that has good high-speed peelability, does not cause zipping, does not contaminate the adherend after peeling, and has little change in peeling force due to the peeling speed. (Meth) acrylic polymer with a glass transition temperature of a certain value or less and a (meth) acrylic polymer with a glass transition temperature of a certain value or less, and a crosslinking reaction so that the gel fraction is a certain value or more. A surface protective sheet obtained by coating a pressure adhesive on a support has been proposed (see Patent Document 1). However, the adhesiveness at the time of low-speed peeling may be inferior, and transparency is not particularly satisfactory.

JP 2005-146151 A

Therefore, in the light of such circumstances, the present invention is a pressure-sensitive adhesive that has low adhesive strength at high-speed peeling, high adhesive strength at low-speed peeling to such an extent that it does not cause problems such as lifting and peeling, and excellent transparency. An object is to provide a composition, and a pressure-sensitive adhesive layer, a pressure-sensitive adhesive sheet, a surface protective sheet, an optical surface protective sheet, and an optical film with a surface protective sheet using the composition.

One embodiment of the present invention is a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition has an alicyclic structure represented by the following general formula (1) having 100 parts by mass of a polymer (A) having a glass transition temperature of less than 0 ° C. and a weight average molecular weight of 1,000 to less than 30,000. 0.05 to 20 parts by mass of (meth) acrylic polymer (B) containing (meth) acrylic monomer and a monomer having a polyoxyalkylene skeleton and a monomer having a polyorganosiloxane skeleton as monomer units; It is characterized by including.
CH ₂ = C (R ¹ ) COOR ² (1)
[In Formula (1), R ¹ is a hydrogen atom or a methyl group, and R ² is an alicyclic hydrocarbon group having an alicyclic structure]

In the pressure-sensitive adhesive composition of the above aspect, the polymer (A) may be an acrylic polymer.

In the pressure-sensitive adhesive composition of the above aspect, the (meth) acrylic polymer (B) may have a crosslinked ring structure even if the alicyclic hydrocarbon group of the (meth) acrylic monomer having an alicyclic structure has a bridged ring structure. Good. In addition, the (meth) acrylic polymer (B) is an oxyalkylene in which the monomer having a polyoxyalkylene skeleton is represented by the following general formula (2) and the average number of added oxyalkylene units is 3 to 40 It may be a group-containing monomer.

[Wherein, R ₁ is hydrogen or a methyl group, R ₂ is hydrogen or a monovalent organic group, m and p are integers of 2 to 4, and n and q are 0 or integers of 2 to 40 , N and q cannot be 0 at the same time]

The (meth) acrylic polymer (B) is a monomer having a polyorganosiloxane skeleton selected from the group of monomers represented by the following general formula (3) or (4): It may be.

[In the formulas (3) and (4), R ₃ is hydrogen or methyl, R ₄ is methyl or a monovalent organic group, and m and n are integers of 0 or more.]

In the pressure-sensitive adhesive composition of the above aspect, the acrylic polymer may further contain a hydroxyl group-containing (meth) acrylic monomer as a monomer component.

In the pressure-sensitive adhesive composition of the above aspect, the acrylic polymer further contains, as a monomer component, 5.0% by mass or less of an oxyalkylene group-containing reactive monomer having an average addition mole number of oxyalkylene units of 3 to 40. May be.

Another aspect of the present invention is a pressure-sensitive adhesive layer. The said adhesive layer consists of an adhesive composition of any aspect mentioned above. The pressure-sensitive adhesive layer of this embodiment may contain 85.00% by mass to 99.95% by mass of a solvent-insoluble component.

Still another aspect of the present invention is an adhesive sheet. The pressure-sensitive adhesive sheet includes the pressure-sensitive adhesive layer according to any one of the above-described aspects.

In the pressure-sensitive adhesive sheet of the above aspect, the support may be a plastic substrate that has been subjected to antistatic treatment.

Still another aspect of the present invention is a surface protective sheet. The said surface protection sheet contains the adhesive sheet of any aspect mentioned above.

Further, the present invention includes an optical surface sheet that uses the surface protective sheet for protecting the surface of the optical film, and an optical film with a surface protective sheet to which the optical surface protective sheet is attached.

According to the present invention, the pressure-sensitive adhesive composition at high speed peeling is small, the adhesive strength at low speed peeling is high enough not to cause problems such as floating and peeling, and excellent transparency, and the use thereof A pressure-sensitive adhesive layer, a pressure-sensitive adhesive sheet, a surface protective sheet, an optical surface protective sheet, and an optical film with a surface protective sheet are provided.

It is a side view explaining the low speed peeling test (constant load peeling) in the Example of this invention. It is a side view explaining the high-speed peeling test (180 degree peeling adhesive force) in the Example of this invention.

The pressure-sensitive adhesive composition according to this embodiment has 100 parts by mass of a polymer (A) having a glass transition temperature of less than 0 ° C. as the pressure-sensitive adhesive composition, a weight average molecular weight of 1,000 to less than 30,000, and the following general formula (1 (Meth) acrylic monomer having a alicyclic structure represented by (II) and a monomer having a polyoxyalkylene skeleton, and a monomer having a polyorganosiloxane skeleton as a monomer unit (B) ( (Hereinafter referred to as “(meth) acrylic polymer (B)”) in an amount of 0.05 to 20 parts by mass.
CH ₂ = C (R ¹ ) COOR ² (1)
[In Formula (1), R ¹ is a hydrogen atom or a methyl group, and R ² is an alicyclic hydrocarbon group having an alicyclic structure]

Hereinafter, the polymer (A) and the (meth) acrylic polymer (B) will be described in detail.

[Polymer (A)]
The polymer (A) is not particularly limited as long as the glass transition temperature is less than 0 ° C., and is generally used as an adhesive such as an acrylic polymer, a rubber polymer, a silicone polymer, a polyurethane polymer, and a polyester polymer. Various polymers can be used. In particular, an acrylic polymer that is easily compatible with the (meth) acrylic polymer (B) and has high transparency is preferable.

The glass transition temperature (Tg) of the polymer (A) is less than 0 ° C., preferably less than −10 ° C., more preferably less than −40 ° C., and usually −80 ° C. or higher. When the glass transition temperature (Tg) of the polymer (A) is 0 ° C. or higher, the polymer is difficult to flow, wetness to the adherend becomes insufficient, and adhesiveness may be lowered.

The glass transition temperature is a nominal value described in literatures, catalogs, or the like, or a value calculated based on the following formula (1) (Fox formula).

_{_{_{1 / Tg = W 1 / Tg}}} 1 + W 2 / Tg 2 + ··· + Wn / Tg n (1)
[In the formula (1), Tg is the glass transition temperature (unit: K) of the polymer (A), and Tg _i (i = 1, 2,... N) is the glass transition when the monomer i forms a homopolymer. Temperature (unit: K), W _i (i = 1, 2,..., N) represents a mass fraction of all monomer components of monomer i. ]
The above formula (1) is a calculation formula when the polymer (A) is composed of n types of monomer components of monomer 1, monomer 2,..., Monomer n.

In the present specification, “glass transition temperature when homopolymer is formed” means “glass transition temperature of homopolymer of the monomer”, and may be referred to as a certain monomer (“monomer X”). ) Is the glass transition temperature (Tg) of a polymer formed using only the monomer component. Specifically, “Polymer Handbook” (3rd edition, John Wiley & Sons, Inc, 1989) lists numerical values. In addition, the glass transition temperature (Tg) of the homopolymer which is not described in the said literature says the value obtained by the following measuring methods, for example. That is, in a reactor equipped with a thermometer, a stirrer, a nitrogen introducing tube and a reflux condenser, 100 parts by weight of monomer X, 0.2 parts by weight of 2,2′-azobisisobutyronitrile, and ethyl acetate 200 as a polymerization solvent. Stirring is performed for 1 hour while introducing nitrogen gas. After removing oxygen in the polymerization system in this way, the temperature is raised to 63 ° C. and the reaction is carried out for 10 hours. Subsequently, it cools to room temperature and the homopolymer solution with a solid content concentration of 33 mass% is obtained. Next, this homopolymer solution is cast-coated on a release liner and dried to prepare a test sample (sheet-like homopolymer) having a thickness of about 2 mm. Then, about 1 to 2 mg of this test sample is weighed in an aluminum open cell, and a nitrogen atmosphere of 50 ml / min is used using a temperature modulation DSC (trade name “Q-2000”, manufactured by T.A. Instruments Inc.). Under the heating rate of 5 ° C./min, the reversing heat flow (specific heat component) behavior of the homopolymer is obtained. Referring to JIS-K-7121, the low temperature side baseline of the obtained Reversing Heat Flow and the straight line that is equidistant in the vertical axis from the straight line that extends the high temperature side baseline, and the stepwise change of the glass transition The temperature at the point where the partial curve intersects is the glass transition temperature (Tg) when the homopolymer is used.

The weight average molecular weight (Mw) of the polymer (A) is, for example, 30,000 to 5,000,000, preferably 100,000 to 2,000,000, more preferably 200,000 to 1,000,000. If the weight average molecular weight (Mw) is less than 30,000, the cohesive force of the pressure-sensitive adhesive may be insufficient, and contamination of the adherend may easily occur. On the other hand, when the weight average molecular weight (Mw) exceeds 5,000,000, the fluidity of the pressure-sensitive adhesive is lowered, the wetness to the adherend is insufficient, and the adhesion may be lowered.

[Acrylic polymer]
Hereinafter, an acrylic polymer which is a preferred specific example of the polymer (A) will be described in detail.

The acrylic polymer is, for example, a polymer containing 50% by mass or more of (meth) acrylic acid alkyl ester having a linear or branched alkyl group having 1 to 20 carbon atoms as a monomer unit. In addition, the acrylic polymer may have a configuration in which (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms is used alone or in combination of two or more. The method for obtaining the acrylic polymer is not particularly limited, and various polymerization methods generally used as synthetic methods for acrylic polymers such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and radiation curing polymerization are applied. Thus, the polymer can be obtained. When the pressure-sensitive adhesive sheet of this embodiment is used as a surface protective sheet described later, solution polymerization and emulsion polymerization can be suitably used.

The proportion of the (meth) acrylic acid alkyl ester having a linear or branched alkyl group having 1 to 20 carbon atoms is 50% by mass to 99.9% by mass with respect to the total amount of monomer components for preparing the acrylic polymer. %, Preferably 60 mass% to 98 mass%, more preferably 70 mass% to 95 mass%.

Examples of the (meth) acrylic acid alkyl ester having a linear or branched alkyl group having 1 to 20 carbon atoms include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, Isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, (meth) acryl Isopentyl acid, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, (meth) Isononyl acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, (meth ) Undecyl acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, (meth) (Meth) acrylic acid C _1-20 alkyl ester such as octadecyl acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate [preferably (meth) acrylic acid C _2-14 alkyl ester, more preferably (meth) ) Acrylic acid C _2-10 alkyl ester] and the like. In addition, (meth) acrylic acid alkyl ester means acrylic acid alkyl ester and / or methacrylic acid alkyl ester, and “(meth)...” Has the same meaning.

Acrylic polymers can be copolymerized with other (meth) acrylic acid alkyl esters as needed for the purpose of modifying cohesion, heat resistance, crosslinkability, etc. Monomer). Therefore, the acrylic polymer may contain a copolymerizable monomer together with the (meth) acrylic acid alkyl ester as the main component. As the copolymerizable monomer, a monomer having a polar group can be suitably used.

As a specific example of the copolymerizable monomer,
Carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid;
(Meth) acrylic acid 2-hydroxyethyl, (meth) acrylic acid 3-hydroxypropyl, (meth) acrylic acid 4-hydroxybutyl, (meth) acrylic acid 6-hydroxyhexyl, (meth) acrylic acid 8-hydroxyoctyl, Hydroxyl group-containing monomers such as (meth) acrylic acid hydroxyalkyl such as (meth) acrylic acid 10-hydroxydecyl, (meth) acrylic acid 12-hydroxylauryl, (4-hydroxymethylcyclohexyl) methyl methacrylate;
Acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride;
Sulphonic acid groups such as styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalene sulfonic acid Containing monomers;
Phosphoric acid group-containing monomers such as 2-hydroxyethylacryloyl phosphate;
(Meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dipropyl (meth) acrylamide, N, N-diisopropyl (meth) acrylamide, N, N-di N, N-dialkyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-isopropyl (meth) such as (n-butyl) (meth) acrylamide, N, N-di (t-butyl) (meth) acrylamide Acrylamide, N-butyl (meth) acrylamide, Nn-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-ethylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, N-methoxymethyl ( (Meth) acrylamide, N-methoxyethyl (meta) Acrylamide, N- butoxymethyl (meth) acrylamide, N- acryloyl morpholine, etc. (N- substituted) amide monomers;
Succinimide monomers such as N- (meth) acryloyloxymethylenesuccinimide, N- (meth) acryloyl-6-oxyhexamethylenesuccinimide, N- (meth) acryloyl-8-oxyhexamethylenesuccinimide;
Maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide;
Itaconimides such as N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide System monomers;
Vinyl esters such as vinyl acetate and vinyl propionate;
N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N- Vinyloxazole, N- (meth) acryloyl-2-pyrrolidone, N- (meth) acryloylpiperidine, N- (meth) acryloylpyrrolidine, N-vinylmorpholine, N-vinyl-2-piperidone, N-vinyl-3-morpholinone N-vinyl-2-caprolactam, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinylisoxazole, N-vinylthiazole, Contains nitrogen such as N-vinylisothiazole and N-vinylpyridazine Ring-based monomer;
N-vinylcarboxylic acid amides;
Lactam monomers such as N-vinylcaprolactam;
Cyano-containing monomers such as acrylonitrile and methacrylonitrile;
(Meth) acrylic such as aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate Acid aminoalkyl monomers;
(Meth) acrylic acid alkoxyalkyl monomers such as (meth) acrylic acid methoxyethyl, (meth) acrylic acid ethoxyethyl, (meth) acrylic acid propoxyethyl, (meth) acrylic acid butoxyethyl, (meth) acrylic acid ethoxypropyl ;
Styrene monomers such as styrene and α-methylstyrene;
Epoxy group-containing acrylic monomers such as (meth) glycidyl acrylate;
(Meth) acrylic acid tetrahydrofurfuryl, fluorine atom-containing (meth) acrylate, silicone (meth) acrylate and other heterocyclic rings, halogen atoms, silicon atoms and the like, acrylic ester monomers;
Olefin monomers such as isoprene, butadiene, isobutylene;
Vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether;
Vinyl esters such as vinyl acetate and vinyl propionate;
Aromatic vinyl compounds such as vinyltoluene and styrene;
Olefins or dienes such as ethylene, butadiene, isoprene, isobutylene;
Vinyl ethers such as vinyl alkyl ethers;
Vinyl chloride;
Sulfonic acid group-containing monomers such as sodium vinyl sulfonate;
Imide group-containing monomers such as cyclohexylmaleimide and isopropylmaleimide;
Isocyanate group-containing monomers such as 2-isocyanatoethyl (meth) acrylate;
Acryloylmorpholine;
(Meth) acrylic acid ester having an alicyclic hydrocarbon group such as cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate;
(Meth) acrylic acid ester having an aromatic hydrocarbon group such as phenyl (meth) acrylate and phenoxyethyl (meth) acrylate;
(Meth) acrylic acid ester obtained from terpene compound derivative alcohol;
Etc. These copolymerizable monomers can be used alone or in combination of two or more.

When the acrylic polymer contains a copolymerizable monomer together with the (meth) acrylic acid alkyl ester as the main component, a hydroxyl group-containing monomer or a carboxyl group-containing monomer can be suitably used. Among them, 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate can be suitably used as the hydroxyl group-containing monomer, and acrylic acid can be suitably used as the carboxyl group-containing monomer. The amount of the copolymerizable monomer used is not particularly limited, but is usually 0.01% by mass to 40% by mass of the copolymerizable monomer with respect to the total amount of monomer components for preparing the acrylic polymer, preferably It can be contained in an amount of 0.1 to 30% by mass, more preferably 0.5 to 20% by mass.

Containing 0.01% by mass or more of the copolymerizable monomer prevents a decrease in cohesive strength of the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer formed of the acrylic pressure-sensitive adhesive composition, and contamination when peeled from the adherend Can be prevented. Moreover, by making content of a copolymerizable monomer into 40 mass% or less, it can prevent that cohesion force becomes high too much and can improve the tuck feeling in normal temperature (25 degreeC).

In the pressure-sensitive adhesive composition, the acrylic polymer may further contain 5.0% by mass or less of an oxyalkylene group-containing reactive monomer having an average addition mole number of oxyalkylene units of 3 to 40 as a monomer component. Good.

The average number of moles of oxyalkylene units added to the oxyalkylene group-containing reactive monomer is 3 to 40 from the viewpoints of peelability at the time of high-speed peeling of the pressure-sensitive adhesive sheet and coating properties of the pressure-sensitive adhesive composition. It is preferably 4 to 35, more preferably 5 to 30. When the average added mole number is 3 or more,
There exists a tendency for the improvement effect of the peelability at the time of high-speed peeling of an adhesive sheet to be acquired efficiently. Moreover, when the said average addition mole number is larger than 40, since there exists a tendency for an adhesive composition to become a gel form and for coating to become difficult, it is unpreferable. The terminal of the oxyalkylene group may be a hydroxyl group or may be substituted with another functional group.

The oxyalkylene group-containing reactive monomer may be used alone or as a mixture of two or more thereof, but the total content is 5. with respect to the total amount of monomer components of the acrylic polymer. It is preferably 0% by mass or less, more preferably 4.0% by mass or less, particularly preferably 3.0% by mass or less, and still more preferably 1.0% by mass or less (usually 0.1% by mass or more). When the content of the oxyalkylene group-containing reactive monomer exceeds 5.0% by mass, the pressure-sensitive adhesive composition tends to be in a gel state and coating becomes difficult, which is not preferable.

Examples of the oxyalkylene unit of the oxyalkylene group-containing reactive monomer include those having an oxyalkylene group having 1 to 6 carbon atoms, such as an oxymethylene group, an oxyethylene group, an oxypropylene group, and an oxybutylene group. It is done. The hydrocarbon group of the oxyalkylene chain may be linear or branched.

Furthermore, the oxyalkylene group-containing reactive monomer is more preferably a reactive monomer having an ethylene oxide group. By using an acrylic polymer having a reactive monomer having an ethylene oxide group as a base polymer, the effect of improving the peelability at the time of high-speed peeling of the pressure-sensitive adhesive sheet can be obtained efficiently.

Examples of oxyalkylene group-containing reactive monomers include (meth) acrylic acid oxyalkylene adducts and reactive surfactants having reactive substituents such as acryloyl, methacryloyl and allyl groups in the molecule. It is done.

Specific examples of the (meth) acrylic acid oxyalkylene adduct include, for example, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, polyethylene glycol-polypropylene glycol (meth) acrylate, polyethylene glycol-polybutylene glycol (meth) ) Acrylate, polypropylene glycol-polybutylene glycol (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, ethoxy polyethylene glycol (meth) acrylate, butoxy polyethylene glycol (meth) acrylate, octoxy polyethylene glycol (meth) acrylate, lauroxy polyethylene Glycol (meth) acrylate, stearoxy polyethylene glycol (Meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, phenoxypolyethyleneglycol-polypropyleneglycol (meth) acrylate, methoxypolypropyleneglycol (meth) acrylate, nonylphenoxypolypropyleneglycol (meth) acrylate, nonylphenoxypolyethyleneglycol (meth) acrylate , Nonylphenoxyethylene glycol-polypropylene glycol (meth) acrylate, octoxypolyethylene glycol-polypropylene glycol (meth) acrylate, polytetramethylene glycol (meth) acrylate, polytetramethylene glycol-polyethylene glycol (meth) acrylate, polytetramethylene glycol -polypropylene Recall (meth) acrylate, polytetramethylene glycol - polybutylene glycol (meth) acrylate, propylene glycol - such as polybutylene glycol (meth) acrylate.

Specific examples of the reactive surfactant include, for example, an anionic reactive surfactant having a (meth) acryloyl group or an allyl group, a nonionic reactive surfactant, and a cationic reactive surfactant. Is mentioned.

Examples of the anionic reactive surfactant include those represented by the formulas (A1) to (A10).

[R ₁ in Formula (A1) represents hydrogen or a methyl group, R ₂ represents a hydrocarbon group having 1 to 30 carbon atoms or an acyl group, X represents an anionic hydrophilic group, R ₃ and R ₄ are They are the same or different and each represents an alkylene group having 1 to 6 carbon atoms, and the average added mole numbers m and n are 0 to 40, where (m + n) represents a number of 3 to 40. ]

[R ₁ in Formula (A2) represents hydrogen or a methyl group, R ₂ and R ₇ are the same or different, represent an alkylene group having 1 to 6 carbon atoms, and R ₃ and R ₅ are the same or different, Represents hydrogen or an alkyl group, R ₄ and R ₆ are the same or different and represent hydrogen, an alkyl group, a benzyl group or a styrene group, X represents an anionic hydrophilic group, and average added mole numbers m and n are 0 to 40, where (m + n) represents a number from 3 to 40. ]

[R ₁ in Formula (A3) represents hydrogen or a methyl group, R ₂ represents an alkylene group having 1 to 6 carbon atoms, X represents an anionic hydrophilic group, and the average number of added moles n is 3 to 40 Represents a number. ]

[R ₁ in Formula (A4) represents hydrogen or a methyl group, R ₂ represents a hydrocarbon group or acyl group having 1 to 30 carbon atoms, and R ₃ and R ₄ may be the same or different, and 6 represents an alkylene group, X represents an anionic hydrophilic group, the average added mole number m and n are 0 to 40, and (m + n) represents a number of 3 to 40. ]

[R ₁ in Formula (A5) represents a hydrocarbon group, an amino group, or a carboxylic acid residue, R ₂ represents an alkylene group having 1 to 6 carbon atoms, X represents an anionic hydrophilic group, and average added mole The number n represents an integer of 3 to 40. ]

[In Formula (A6), R ₁ represents a hydrocarbon group having 1 to 30 carbon atoms, R ₂ represents hydrogen or a hydrocarbon group having 1 to 30 carbon atoms, R ₃ represents hydrogen or a propenyl group, and R ₄ represents Represents an alkylene group having 1 to 6 carbon atoms, X represents an anionic hydrophilic group, and the average added mole number n represents a number of 3 to 40; ]

[R ₁ in Formula (A7) represents hydrogen or a methyl group, R ₂ and R ₄ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms, and R ₃ represents a hydrocarbon having 1 to 30 carbon atoms. M represents hydrogen, an alkali metal, an ammonium group, or an alkanol ammonium group, and the average number of added moles m and n is 0 to 40, where (m + n) represents a number of 3 to 40. ]

[And _{R 1} and _{R 5} in the formula (A8) the same or different, represent a hydrogen or a methyl group, _{R 2} and _{R 4} are the same or different and each represents an alkylene group having a carbon number of 1 to 6, _{R 3} is Represents a hydrocarbon group having 1 to 30 carbon atoms, M represents hydrogen, an alkali metal, an ammonium group, or an alkanol ammonium group, and the average number of added moles m and n is 0 to 40, provided that (m + n) is 3 to 40 Represents a number. ]

[R ₁ in Formula (A9) represents an alkylene group having 1 to 6 carbon atoms, R ₂ represents a hydrocarbon group having 1 to 30 carbon atoms, and M represents hydrogen, an alkali metal, an ammonium group, or an alkanol ammonium group. The average added mole number n represents a number of 3 to 40. ]

[R ₁ , R ₂ and R _{3 in} Formula (A10) are the same or different and represent hydrogen or a methyl group, and R ₄ represents a hydrocarbon group having 0 to 30 carbon atoms (in the case of 0 carbon atoms, R ₄ R ₅ and R ₆ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms, X represents an anionic hydrophilic group, and average added mole numbers m and n are 0 to 40, where (m + n) represents a number from 3 to 40. ]

X in the above formulas (A1) to (A6) and (A10) represents an anionic hydrophilic group. Examples of the anionic hydrophilic group include those represented by the following formulas (a1) to (a2).

[M1 in Formula (a1) represents hydrogen, an alkali metal, an ammonium group, or an alkanol ammonium group. ]

[M2 and M3 in Formula (a2) are the same or different and represent hydrogen, an alkali metal, an ammonium group, or an alkanol ammonium group. ]

Examples of the nonionic reactive surfactant include those represented by the formulas (N1) to (N6).

[R ₁ in Formula (N1) represents hydrogen or a methyl group, R ₂ represents a hydrocarbon group or an acyl group having 1 to 30 carbon atoms, and R ₃ and R ₄ may be the same or different, and 6 represents an alkylene group, and average addition mole numbers m and n are 0 to 40, where (m + n) represents a number of 3 to 40. ]

[R ₁ in Formula (N2) represents hydrogen or a methyl group, R ₂ , R ₃ and R ₄ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms, and the average number of added moles n, m, And l represents a number from 0 to 40, and (n + m + 1) is 3 to 40. ]

[R ₁ in Formula (N3) represents hydrogen or a methyl group, R ₂ and R ₃ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms, and R ₄ represents a hydrocarbon having 1 to 30 carbon atoms. A group or an acyl group, and the average addition mole numbers m and n are 0 to 40, where (m + n) represents a number of 3 to 40. ]

[R ₁ and R _{2 in} formula (N4) are the same or different and each represents a hydrocarbon group having 1 to 30 carbon atoms, R ₃ represents hydrogen or a propenyl group, and R ₄ represents an alkylene having 1 to 6 carbon atoms The average added mole number n represents a number of 3 to 40. ]

[In formula (N5), R ₁ and R ₃ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms; R ₂ and R ₄ are the same or different and represent hydrogen or a hydrocarbon having 1 to 30 carbon atoms; An average addition mole number m and n are 0 to 40, and (m + n) is a number of 3 to 40. ]

[R ₁ , R ₂ and R _{3 in} Formula (N6) are the same or different and represent hydrogen or a methyl group, and R ₄ represents a hydrocarbon group having 0 to 30 carbon atoms (in the case of 0 carbon atoms, R ₄ R ₅ and R ₆ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms, and the average added mole numbers m and n are 0 to 40, provided that (m + n) is 3 to The number of 40 is represented. ]

Specific examples of commercially available oxyalkylene group-containing reactive monomers include, for example, Blemmer PME-400, Blemmer PME-1000, Blemmer 50POEP-800B (all of which are manufactured by NOF Corporation), Latemul PD-420. LATEMUL PD-430 (all above, manufactured by Kao Corporation), Adekaria soap ER-10, Adekaria soap NE-10 (all above, all manufactured by Asahi Denka Kogyo Co., Ltd.), and the like.

The acrylic polymer may contain a polyfunctional monomer as necessary in order to adjust the cohesive strength of the pressure-sensitive adhesive composition to be formed.

Examples of the polyfunctional monomer include (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, and pentaerythritol. Tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,2-ethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate , Trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, Li acrylates, urethane acrylates, 1,4-butanediol di (meth) acrylate. Among these, trimethylolpropane tri (meth) acrylate, hexanediol di (meth) acrylate, and dipentaerythritol hexa (meth) acrylate can be preferably used. A polyfunctional monomer can be used individually or in combination of 2 or more types.

The amount of the polyfunctional monomer used varies depending on the molecular weight and the number of functional groups, but is 0.01% by mass to 3.0% by mass, preferably 0%, based on the total amount of monomer components for preparing the acrylic polymer. It is added in an amount of 0.02 mass% to 2.0 mass%, more preferably 0.03 mass% to 1.0 mass%.

When the amount of the polyfunctional monomer used exceeds 3.0% by mass with respect to the total amount of monomer components for preparing the acrylic polymer, for example, the cohesive force of the pressure-sensitive adhesive composition becomes too high, and the adhesive force (high speed (Peeling force, low-speed peeling force) may decrease. On the other hand, when the content is less than 0.01% by mass, for example, the cohesive force of the pressure-sensitive adhesive composition may be reduced, and may be contaminated when peeled off from the adherend (protected body).

When preparing an acrylic polymer, it is possible to easily form an acrylic polymer by using a curing reaction by heat or ultraviolet rays using a polymerization initiator such as a thermal polymerization initiator or a photopolymerization initiator (photoinitiator). it can. In particular, thermal polymerization can be suitably used because of the advantage that the polymerization time can be shortened. A polymerization initiator can be used individually or in combination of 2 or more types.

Examples of the thermal polymerization initiator include azo polymerization initiators (for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis-2-methylbutyronitrile, 2,2′-azobis ( 2-methylpropionic acid) dimethyl, 4,4'-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis [2 -(5-Methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis (2-methylpropionamidine) disulfate, 2,2'-azobis (N, N'-dimethylene) Isobutylamidine) dihydrochloride, etc.); peroxide polymerization initiators (eg, dibenzoyl peroxide, t-butylpermaleate, lauroy peroxide) Etc.); redox polymerization initiators, and the like.

The amount of the thermal polymerization initiator used is not particularly limited, but for example, 0.01 parts by mass to 5 parts by mass, preferably 0.05 parts by mass to 3 parts by mass with respect to 100 parts by mass of the monomer component for preparing the acrylic polymer. It mix | blends in the quantity in the range of the mass part.

The photopolymerization initiator is not particularly limited, but for example, benzoin ether photopolymerization initiator, acetophenone photopolymerization initiator, α-ketol photopolymerization initiator, aromatic sulfonyl chloride photopolymerization initiator, photoactive Oxime photopolymerization initiator, benzoin photopolymerization initiator, benzyl photopolymerization initiator, benzophenone photopolymerization initiator, ketal photopolymerization initiator, thioxanthone photopolymerization initiator, acylphosphine oxide photopolymerization initiator An agent or the like can be used.

Specifically, examples of the benzoin ether photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane- 1-one [trade name: Irgacure 651, manufactured by BASF Corporation], anisoin and the like can be mentioned. Examples of the acetophenone photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone [trade name: Irgacure 184, manufactured by BASF], 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 1- [4- ( 2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one [trade name: Irgacure 2959, manufactured by BASF Corp.], 2-hydroxy-2-methyl-1-phenyl-propane- 1-one [trade name: Darocur 1173, manufactured by BASF], methoxyacetophenone, and the like can be given. Examples of the α-ketol photopolymerization initiator include 2-methyl-2-hydroxypropiophenone, 1- [4- (2-hydroxyethyl) -phenyl] -2-hydroxy-2-methylpropane-1- ON etc. are mentioned. Examples of the aromatic sulfonyl chloride photopolymerization initiator include 2-naphthalenesulfonyl chloride. Examples of the photoactive oxime photopolymerization initiator include 1-phenyl-1,2-propanedione-2- (O-ethoxycarbonyl) oxime.

The benzoin photopolymerization initiator includes, for example, benzoin. Examples of the benzyl photopolymerization initiator include benzyl and the like. Examples of the benzophenone photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3′-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexyl phenyl ketone, and the like. Examples of the ketal photopolymerization initiator include benzyl dimethyl ketal. Examples of the thioxanthone photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone and the like are included.

Examples of the acylphosphine photopolymerization initiator include bis (2,6-dimethoxybenzoyl) phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) (2,4,4-trimethylpentyl) phosphine oxide, bis ( 2,6-dimethoxybenzoyl) -n-butylphosphine oxide, bis (2,6-dimethoxybenzoyl)-(2-methylpropan-1-yl) phosphine oxide, bis (2,6-dimethoxybenzoyl)-(1- Methylpropan-1-yl) phosphine oxide, bis (2,6-dimethoxybenzoyl) -t-butylphosphine oxide, bis (2,6-dimethoxybenzoyl) cyclohexylphosphine oxide, bis (2,6-dimethoxybenzoyl) octylphosphine Oxides, bis (2 Methoxybenzoyl) (2-methylpropan-1-yl) phosphine oxide, bis (2-methoxybenzoyl) (1-methylpropan-1-yl) phosphine oxide, bis (2,6-diethoxybenzoyl) (2-methyl Propan-1-yl) phosphine oxide, bis (2,6-diethoxybenzoyl) (1-methylpropan-1-yl) phosphine oxide, bis (2,6-dibutoxybenzoyl) (2-methylpropane-1- Yl) phosphine oxide, bis (2,4-dimethoxybenzoyl) (2-methylpropan-1-yl) phosphine oxide, bis (2,4,6-trimethylbenzoyl) (2,4-dipentoxyphenyl) phosphine oxide Bis (2,6-dimethoxybenzoyl) benzylphosphine oxide, bi (2,6-dimethoxybenzoyl) -2-phenylpropylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2-phenylethylphosphine oxide, bis (2,6-dimethoxybenzoyl) benzylphosphine oxide, bis (2, 6-dimethoxybenzoyl) -2-phenylpropylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2-phenylethylphosphine oxide, 2,6-dimethoxybenzoylbenzylbutylphosphine oxide, 2,6-dimethoxybenzoylbenzyloctylphosphine Oxide, bis (2,4,6-trimethylbenzoyl) -2,5-diisopropylphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2-methylphenylphosphine oxide, bis ( , 4,6-trimethylbenzoyl) -4-methylphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,5-diethylphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2 , 3,5,6-tetramethylphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,4-di-n-butoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, Bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, Bis (2,4,6-trimethylbenzoyl) isobutylphosphine oxide, 2,6-Dimethoxybenzoyl-2,4,6- Trimethylbenzoyl-n-butylphosphine oxide, bis (2,4 6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,4-dibutoxyphenylphosphine oxide, 1,10-bis [bis (2,4,6-trimethylbenzoyl) phosphine oxide Decane, tri (2-methylbenzoyl) phosphine oxide, and the like.

The amount of the photopolymerization initiator used is not particularly limited, but for example, 0.01 parts by mass to 5 parts by mass, preferably 0.05 parts by mass to 3 parts by mass with respect to 100 parts by mass of the monomer component for preparing the acrylic polymer. In an amount within the range of parts.

Here, if the amount of the photopolymerization initiator used is less than 0.01 parts by mass, the polymerization reaction may become insufficient. When the usage-amount of a photoinitiator exceeds 5 mass parts, an ultraviolet-ray may not reach the inside of an adhesive layer because a photoinitiator absorbs an ultraviolet-ray. In this case, the polymerization rate is lowered, or the molecular weight of the produced polymer is reduced. And the cohesive force of the adhesive layer formed becomes low by this, and when it peels from a to-be-adhered body (protected body), it may contaminate. In addition, a photopolymerization initiator can be used individually or in combination of 2 or more types.

In this embodiment, the acrylic polymer is prepared as a partial polymer (acrylic polymer syrup) in which the monomer component is partially polymerized by irradiating the mixture containing the monomer component and the polymerization initiator with ultraviolet rays (UV). You can also A pressure-sensitive adhesive composition is prepared by blending the acrylic polymer syrup with a (meth) acrylic polymer (B), which will be described later, and this pressure-sensitive adhesive composition is applied to a predetermined substrate and irradiated with ultraviolet rays. The polymerization can also be completed.

[(Meth) acrylic polymer (B)]
The (meth) acrylic polymer (B) has a weight average molecular weight of 1000 or more and less than 30000 and has an alicyclic structure represented by the following general formula (1) and a polyoxyalkylene skeleton And a (meth) acrylic polymer containing a monomer having a polyorganosiloxane skeleton as a monomer unit, and functions as an additive for adjusting peelability in the pressure-sensitive adhesive composition.
CH ₂ = C (R ¹ ) COOR ² (1)
[In Formula (1), R ¹ is a hydrogen atom or a methyl group, and R ² is an alicyclic hydrocarbon group having an alicyclic structure]

Examples of the alicyclic hydrocarbon group R ² in the general formula (1) include alicyclic hydrocarbon groups such as a cyclohexyl group, an isobornyl group, and a dicyclopentanyl group. Examples of such (meth) acrylic monomers having an alicyclic hydrocarbon group include cyclohexyl (meth) acrylate having a cyclohexyl group, isobornyl (meth) acrylate having an isobornyl group, and a dicyclopentanyl group. Mention may be made of esters of (meth) acrylic acid with alicyclic alcohols such as (meth) acrylic acid dicyclopentanyl. Thus, by providing the (meth) acrylic polymer (B) as a monomer unit with the (meth) acrylic monomer having a relatively bulky structure, it is possible to improve the adhesiveness during low-speed peeling.

Furthermore, the alicyclic hydrocarbon group of the (meth) acrylic monomer having an alicyclic structure constituting the (meth) acrylic polymer (B) preferably has a bridged ring structure. The bridged ring structure refers to an alicyclic structure having three or more rings. By giving the (meth) acrylic polymer (B) a more bulky structure such as a bridged ring structure, the adhesiveness of the pressure-sensitive adhesive composition (pressure-sensitive adhesive sheet) can be further improved. In particular, the adhesiveness at the time of low speed peeling can be remarkably improved.

Examples of R ² that is an alicyclic hydrocarbon group having a bridged ring structure include a dicyclopentanyl group represented by the following formula (3a), a dicyclopentenyl group represented by the following formula (3b), Examples thereof include an adamantyl group represented by the following formula (3c), a tricyclopentanyl group represented by the following formula (3d), and a tricyclopentenyl group represented by the following formula (3e). In addition, when UV polymerization is employed in the synthesis of the (meth) acrylic polymer (B) or in the preparation of the pressure-sensitive adhesive composition, it is difficult to cause polymerization inhibition. Among (meth) acrylic monomers having a ring or higher alicyclic structure, in particular, a dicyclopentanyl group represented by the following formula (3a), an adamantyl group represented by the following formula (3c), and the following formula A (meth) acrylic monomer having a saturated structure such as a tricyclopentanyl group represented by (3d) can be suitably used as a monomer constituting the (meth) acrylic polymer (B).

Examples of (meth) acrylic monomers having a tricyclic or higher alicyclic structure having such a bridged ring structure include dicyclopentanyl methacrylate, dicyclopentanyl acrylate, and dicyclopentanyloxyethyl. Methacrylate, dicyclopentanyloxyethyl acrylate, tricyclopentanyl methacrylate, tricyclopentanyl acrylate, 1-adamantyl methacrylate, 1-adamantyl acrylate, 2-methyl-2-adamantyl methacrylate, 2-methyl-2-adamantyl acrylate, Mention may be made of (meth) acrylic acid esters such as 2-ethyl-2-adamantyl methacrylate and 2-ethyl-2-adamantyl acrylate. These (meth) acrylic monomers can be used alone or in combination of two or more.

As the monomer having a polyoxyalkylene skeleton constituting the (meth) acrylic polymer (B), an oxyalkylene group-containing reactive monomer constituting the polymer (A) described above can be used. In other words, (meth) acrylic acid oxyalkylene adducts, anionic reactive surfactants having reactive substituents such as acryloyl group, methacryloyl group, and allyl group in the molecule, nonionic reactive surfactants, cationic reactions Surfactants and the like. The polyoxyalkylene chain can exhibit a proper balance between incompatibility and incompatibility between the polymer (A) and the (meth) acrylic polymer (B), and can appropriately adjust the releasability during re-peeling. . In particular, an oxyalkylene group-containing monomer represented by the following general formula (2) can be suitably used.

(2)
[In the formula (2), R ₁ is hydrogen or a methyl group, R ₂ is hydrogen or a monovalent organic group, m and p are integers of 2 to 4, and n and q are 0 or 2 to 40 Is an integer and n and q cannot be 0 at the same time]

Specific examples of the oxyalkylene group-containing monomer include, for example, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, polyethylene glycol-polypropylene glycol (meth) acrylate, polyethylene glycol-polybutylene glycol (meth) acrylate, and polypropylene glycol. -Polybutylene glycol (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, ethoxy polyethylene glycol (meth) acrylate, butoxy polyethylene glycol (meth) acrylate, octoxy polyethylene glycol (meth) acrylate, lauroxy polyethylene glycol (meth) acrylate , Stearoxy polyethylene glycol (meth) a Relate, phenoxypolyethylene glycol (meth) acrylate, phenoxypolyethyleneglycol-polypropyleneglycol (meth) acrylate, methoxypolypropyleneglycol (meth) acrylate, nonylphenoxypolypropyleneglycol (meth) acrylate, nonylphenoxypolyethyleneglycol (meth) acrylate, nonylphenoxyethylene Glycol-polypropylene glycol (meth) acrylate, octoxypolyethylene glycol-polypropylene glycol (meth) acrylate, polytetramethylene glycol (meth) acrylate, polytetramethylene glycol-polyethylene glycol (meth) acrylate, polytetramethylene glycol-polypropylene glycol ( Me ) Acrylate, polytetramethylene glycol - polybutylene glycol (meth) acrylate, propylene glycol - such as polybutylene glycol (meth) acrylate. These oxyalkylene group-containing monomers can be used alone or in combination of two or more.

Among the above, the polymer (A) is an oxyalkylene group-containing monomer having an average addition mole number of oxyalkylene units (the sum of n and q in the general formula (2) is 3 to 40). From the viewpoint of the compatibility of the above and the balance of adhesion reliability as a pressure-sensitive adhesive composition.

The monomer having a polyorganosiloxane skeleton constituting the (meth) acrylic polymer (B) is not particularly limited, and any polyorganosiloxane skeleton-containing monomer can be used. Because the polyorganosiloxane skeleton-containing monomer has low polarity derived from its structure, it actively promotes the uneven distribution of the (meth) acrylic polymer (B) on the surface of the optical film that is the adherend, and is excellent Expresses high-speed release.

As a specific example of the polyorganosiloxane skeleton-containing monomer, for example, a polyorganosiloxane skeleton-containing monomer represented by the following general formula (3) or (4) can be used. More specifically, examples of one-end reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. include X-22-174DX, X-22-2426, X-22-2475, and the like. Can be used in combination.

The (meth) acrylic polymer (B) may be a copolymer of a (meth) acrylic monomer having an alicyclic structure, a monomer having a polyoxyalkylene skeleton, and a monomer having a polyorganosiloxane skeleton. Or a (meth) acrylic monomer having an alicyclic structure, a monomer having a polyoxyalkylene skeleton, a monomer having a polyorganosiloxane skeleton, and another (meth) acrylic acid ester monomer or a copolymerizable monomer It may be a coalescence.

Examples of such (meth) acrylic acid ester monomers include
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate , T-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate, (meth ) Octyl acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, (meth) (Meth) acrylic acid alkyl esters such as dodecyl acrylate;
(Meth) acrylic acid aryl esters such as phenyl (meth) acrylate and benzyl (meth) acrylate;
(Meth) acrylic acid ester obtained from terpene compound derivative alcohol;
Etc. Such (meth) acrylic acid esters can be used alone or in combination of two or more.

The (meth) acrylic polymer (B) contains, in addition to the (meth) acrylic acid ester component unit, other monomer components (copolymerizable monomers) copolymerizable with the (meth) acrylic acid ester. It can also be obtained by polymerization. For example, in the (meth) acrylic polymer (B), a functional group having reactivity with an epoxy group or an isocyanate group may be introduced. Examples of such a functional group include a hydroxyl group, a carboxyl group, an amino group, an amide group, and a mercapto group, and a monomer having such a functional group when the (meth) acrylic polymer (B) is produced. May be used (copolymerization).

As other monomer copolymerizable with (meth) acrylic acid ester,
Carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid;
Alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxypropyl (meth) acrylate monomer;
(Meth) acrylic acid alkali metal salts and the like;
Di (meth) acrylic acid ester of ethylene glycol, di (meth) acrylic acid ester of diethylene glycol, di (meth) acrylic acid ester of triethylene glycol, di (meth) acrylic acid ester of polyethylene glycol, di (meta) of propylene glycol ) (Poly) oxyalkylene di (meth) acrylate monomers such as acrylate esters, di (meth) acrylate esters of dipropylene glycol, di (meth) acrylate esters of tripropylene glycol;
Polyvalent (meth) acrylate monomers such as trimethylolpropane tri (meth) acrylate;
Vinyl esters such as vinyl acetate and vinyl propionate;
Vinyl halide compounds such as vinylidene chloride and 2-chloroethyl (meth) acrylate;
An oxazoline group-containing polymerizable compound such as 2-vinyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline;
Aziridine group-containing polymerizable compounds such as (meth) acryloylaziridine and (meth) acrylic acid-2-aziridinylethyl;
Epoxy group-containing vinyl monomers such as allyl glycidyl ether, (meth) acrylic acid glycidyl ether, (meth) acrylic acid-2-ethylglycidyl ether;
Hydroxyl group-containing vinyl monomers such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, adducts of lactones with 2-hydroxyethyl (meth) acrylate;
Fluorine-containing vinyl monomers such as fluorine-substituted (meth) acrylic acid alkyl esters;
Acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride;
Aromatic vinyl compound monomers such as styrene, α-methylstyrene, vinyltoluene;
Reactive halogen-containing vinyl monomers such as 2-chloroethyl vinyl ether and monochloro vinyl acetate;
(Meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, N An amide group-containing vinyl monomer such as ethylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, N-methoxyethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-acryloylmorpholine;
Succinimide monomers such as N- (meth) acryloyloxymethylenesuccinimide, N- (meth) acryloyl-6-oxyhexamethylenesuccinimide, N- (meth) acryloyl-8-oxyhexamethylenesuccinimide;
Maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide;
Itaconimides such as N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide System monomers;
N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N- Vinyloxazole, N- (meth) acryloyl-2-pyrrolidone, N- (meth) acryloylpiperidine, N- (meth) acryloylpyrrolidine, N-vinylmorpholine, N-vinylpyrazole, N-vinylisoxazole, N-vinylthiazole Nitrogen-containing heterocyclic monomers such as N-vinylisothiazole and N-vinylpyridazine;
N-vinylcarboxylic acid amides;
Lactam monomers such as N-vinylcaprolactam;
Cyanoacrylate monomers such as (meth) acrylonitrile;
(Meth) acrylic such as aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate Acid aminoalkyl monomers;
Imide group-containing monomers such as cyclohexylmaleimide and isopropylmaleimide;
Isocyanate group-containing monomers such as 2-isocyanatoethyl (meth) acrylate;
Organosilicon-containing vinyl monomers such as vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, allyltrimethoxysilane, trimethoxysilylpropylallylamine, 2-methoxyethoxytrimethoxysilane;
Hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxyhexyl (meth) acrylate, hydroxyoctyl (meth) acrylate, hydroxydecyl (meth) acrylate, (meta Hydroxyl group-containing monomers such as hydroxyalkyl (meth) acrylates such as hydroxylauryl acrylate and (4-hydroxymethylcyclohexyl) methyl methacrylate;
(Meth) acrylic acid tetrahydrofurfuryl, fluorine atom-containing (meth) acrylate, silicone (meth) acrylate and other heterocyclic rings, halogen atoms, silicon atoms and the like, acrylic ester monomers;
Olefin monomers such as isoprene, butadiene, isobutylene;
Vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether;
Olefins or dienes such as ethylene, butadiene, isoprene, isobutylene;
Vinyl ethers such as vinyl alkyl ethers;
Vinyl chloride;
Other examples include macromonomers having a radical polymerizable vinyl group at the terminal of a monomer obtained by polymerizing a vinyl group. These monomers can be copolymerized with the (meth) acrylic acid ester alone or in combination.

Examples of the (meth) acrylic polymer (B) include a copolymer of dicyclopentanyl methacrylate (DCPMA), methoxypolyethylene glycol methacrylate, and X-22-2475, isobornyl methacrylate (IBXMA), and methoxypolyethylene glycol. Copolymer of methacrylate and X-22-2475, Copolymer of cyclohexyl methacrylate (CHMA) and methoxypolyethylene glycol methacrylate and X-22-2475, Dicyclopentanyl methacrylate (DCPMA), methyl methacrylate (MMA) and methoxypolyethylene Copolymer of glycol methacrylate and X-22-2475, dicyclopentanyl methacrylate (DCPMA), methoxypolyethylene glycol methacrylate and X- 2-2475 and copolymers of X-22-174DX, and the like.

(Meth) acrylic polymer (B), (meth) acrylic monomer having alicyclic structure, monomer having polyoxyalkylene skeleton, monomer having polyorganosiloxane skeleton and other (meth) acrylic acid ester monomer In the case where a copolymer with a copolymerizable monomer is used, the content ratio of the (meth) acrylic monomer having an alicyclic structure is 5 mass in the total monomer constituting the (meth) acrylic polymer (B). % Or more, preferably 7% by mass or more, more preferably 10% by mass or more (usually less than 80% by mass, preferably 70% by mass or less). If 5 mass% or more of the (meth) acrylic-type monomer which has an alicyclic structure is contained, the adhesiveness at the time of low speed peeling can be improved, without reducing transparency. If it is less than 5% by mass, the adhesiveness, particularly the adhesiveness at the time of low-speed peeling may be inferior.

(Meth) acrylic polymer (B), (meth) acrylic monomer having alicyclic structure, monomer having polyoxyalkylene skeleton, monomer having polyorganosiloxane skeleton and other (meth) acrylic acid ester monomer In the case of a copolymer with a copolymerizable monomer, the content ratio of the monomer having a polyoxyalkylene skeleton is 5% by mass or more in the total monomers constituting the (meth) acrylic polymer (B), preferably It is preferably 10% by mass or more, more preferably 15% by mass or more, and further preferably 20% by mass or more (usually less than 80% by mass, preferably 70% by mass or less). If the monomer having a polyoxyalkylene skeleton is contained in an amount of 5% by mass or more, adhesion reliability and appropriate removability can be obtained in a balanced manner without lowering transparency. When the amount is less than 5% by mass, there may be a problem that the adhesiveness, particularly the adhesive force at high-speed peeling is too high.

(Meth) acrylic polymer (B), (meth) acrylic monomer having alicyclic structure, monomer having polyoxyalkylene skeleton, monomer having polyorganosiloxane skeleton and other (meth) acrylic acid ester monomer In the case of a copolymer with a copolymerizable monomer, the content ratio of the monomer having a polyorganosiloxane skeleton is 5% by mass or more in the total monomers constituting the (meth) acrylic polymer (B), preferably It is preferably 10% by mass or more, more preferably 15% by mass or more, and further preferably 20% by mass or more (usually less than 80% by mass, preferably 70% by mass or less). If the monomer having a polyorganosiloxane skeleton is contained in an amount of 5% by mass or more, the adhesive force during high-speed peeling can be lowered without lowering the transparency. There may be a problem that the adhesive force during high-speed peeling is too high.

The weight average molecular weight of the (meth) acrylic polymer (B) is 1000 or more and less than 30000, preferably 1500 or more and less than 20000, and more preferably 2000 or more and less than 10,000. When the weight average molecular weight is 30000 or more, the adhesiveness during low-speed peeling is lowered. Moreover, since it becomes low molecular weight as a weight average molecular weight is less than 1000, it causes the fall of the adhesive force (high-speed peeling force, low-speed peeling force) of an adhesive sheet.

The measurement of the weight average molecular weight of the polymer (A) or the (meth) acrylic polymer (B) can be obtained in terms of polystyrene by gel permeation chromatography (GPC) method. Specifically, it is measured according to the method and conditions described in the examples described later.

The (meth) acrylic polymer (B) is obtained by, for example, polymerizing a (meth) acrylic monomer having the above-described structure by a solution polymerization method, a bulk polymerization method, an emulsion polymerization method, a suspension polymerization, a bulk polymerization, or the like. Can be produced.

In order to adjust the molecular weight of the (meth) acrylic polymer (B), a chain transfer agent can be used during the polymerization. Examples of chain transfer agents used include compounds having a mercapto group such as octyl mercaptan, lauryl mercaptan, t-nonyl mercaptan, t-dodecyl mercaptan, mercaptoethanol, thioglycerol; thioglycolic acid, methyl thioglycolate, thioglycol Of ethyl acetate, propyl thioglycolate, butyl thioglycolate, t-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, isooctyl thioglycolate, decyl thioglycolate, dodecyl thioglycolate, ethylene glycol Thioglycolates such as thioglycolate, neopentyl glycol thioglycolate, pentaerythritol thioglycolate; α-methyl Chirendaima, and the like.

The amount of the chain transfer agent to be used is not particularly limited, but is usually 0.1 to 20 parts by mass, preferably 0.2 parts by mass with respect to 100 parts by mass of the (meth) acrylic monomer. Part to 15 parts by weight, more preferably 0.3 part to 10 parts by weight. Thus, the (meth) acrylic-type polymer (B) of a suitable molecular weight can be obtained by adjusting the addition amount of a chain transfer agent. In addition, a chain transfer agent can be used individually or in combination of 2 or more types.

[Adhesive composition]
The pressure-sensitive adhesive composition contains the aforementioned polymer (A) and (meth) acrylic polymer (B) as essential components. The content of the (meth) acrylic polymer (B) is 0.05 to 20 parts by mass with respect to 100 parts by mass of the polymer (A), preferably 0.08 to 10 parts by mass. More preferably 0.1 to 5 parts by mass. When the (meth) acrylic polymer (B) is added in excess of 20 parts by mass, the transparency of the pressure-sensitive adhesive layer formed with the pressure-sensitive adhesive composition according to this embodiment is lowered. Also, when the addition amount of the (meth) acrylic polymer (B) is less than 0.05 parts by mass, the adhesive strength at the time of high-speed peeling is small, and at the time of low-speed peeling to the extent that problems such as lifting and peeling do not occur The adhesion property of the adhesive strength is not high enough.

The pressure-sensitive adhesive composition may contain various additives generally used in the field of pressure-sensitive adhesive compositions as optional components, in addition to the polymer (A) and the (meth) acrylic polymer (B) described above. Such optional components include tackifier resins, crosslinking agents, catalysts, plasticizers, softeners, fillers, colorants (pigments, dyes, etc.), antioxidants, leveling agents, stabilizers, preservatives, antistatic agents, etc. Is exemplified. Conventionally known additives can be used as such additives.

In order to adjust the cohesive force of the pressure-sensitive adhesive layer described later, a crosslinking agent can be used in addition to the above-mentioned polyfunctional monomer. As the crosslinking agent, a commonly used crosslinking agent can be used. For example, epoxy crosslinking agent, isocyanate crosslinking agent, silicone crosslinking agent, oxazoline crosslinking agent, aziridine crosslinking agent, silane crosslinking agent, alkyl etherification A melamine type crosslinking agent, a metal chelate type crosslinking agent, etc. can be mentioned. In particular, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, and a metal chelate-based crosslinking agent can be preferably used. These compounds may be used alone or in combination of two or more.

Specifically, examples of isocyanate-based crosslinking agents include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, tetramethylxylylene diisocyanate, naphthalene. Examples include diisocyanate, triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate, and adducts of these with polyols such as trimethylolpropane. Alternatively, a compound having at least one isocyanate group and one or more unsaturated bonds in one molecule, specifically, 2-isocyanatoethyl (meth) acrylate may be used as an isocyanate-based crosslinking agent. Can do. These compounds may be used alone or in combination of two or more.

Epoxy crosslinking agents include bisphenol A, epichlorohydrin type epoxy resin, ethylene glycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol glycidyl ether, trimethylol propane tri Glycidyl ether, diglycidyl aniline, diamine glycidyl amine, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, etc. Can do. These compounds may be used alone or in combination of two or more.

Examples of the metal chelate compound include aluminum, iron, tin, titanium and nickel as metal components, and acetylene, methyl acetoacetate and ethyl lactate as chelate components. These compounds may be used alone or in combination of two or more.

The content of the crosslinking agent is preferably 0.01 to 15 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the polymer (A). preferable. When the content is less than 0.01 parts by mass, the cohesive force of the pressure-sensitive adhesive composition becomes small, and contamination of the adherend may occur. On the other hand, when the content exceeds 15 parts by mass, the cohesive force of the pressure-sensitive adhesive composition is large, the fluidity is lowered, the wettability is insufficient, and the adhesiveness may be lowered.

The pressure-sensitive adhesive composition disclosed herein can further contain a crosslinking catalyst for causing any of the above-described crosslinking reactions to proceed more effectively. As such a crosslinking catalyst, for example, a tin-based catalyst (particularly dioctyltin dilaurate) can be preferably used. The amount of the crosslinking catalyst (for example, a tin-based catalyst such as dioctyltin dilaurate) is not particularly limited, and can be, for example, about 0.0001 parts by mass to 1 part by mass with respect to 100 parts by mass of the polymer (A). .

The pressure-sensitive adhesive composition disclosed herein can contain an antistatic agent for imparting antistatic performance. As such an antistatic agent, for example, an ionic compound can be preferably used. The ionic compound is a compound that exhibits ionic dissociation properties at room temperature, and examples thereof include alkali metal salts and ionic liquids. Since the ionic compound exhibits excellent electrical conductivity, it is useful because it can provide sufficient antistatic performance when contained in a small amount in the pressure-sensitive adhesive. The amount of the ionic compound used is not particularly limited, but can be, for example, about 0.005 to 1 part by mass with respect to 100 parts by mass of the polymer (A). These compounds may be used alone or in combination of two or more.

The pressure-sensitive adhesive composition disclosed herein can contain a compound that causes keto-enol tautomerism. For example, in a pressure-sensitive adhesive composition containing a cross-linking agent or a pressure-sensitive adhesive composition that can be used by blending a cross-linking agent, an embodiment containing a compound that causes the keto-enol tautomerism can be preferably employed. Thereby, the excessive viscosity raise and gelation of the adhesive composition after a crosslinking agent mixing | blending can be suppressed, and the effect of extending the pot life of this composition may be implement | achieved. When at least an isocyanate compound is used as the crosslinking agent, it is particularly meaningful to contain a compound that causes keto-enol tautomerism. This technique can be preferably applied when, for example, the pressure-sensitive adhesive composition is in an organic solvent solution or a solvent-free form.

Various β-dicarbonyl compounds can be used as the compound that causes keto-enol tautomerism. Specific examples include acetylacetone, 2,4-hexanedione, 3,5-heptanedione, 2-methylhexane-3,5-dione, 6-methylheptane-2,4-dione, 2,6-dimethylheptane- Β-diketones such as 3,5-dione; acetoacetates such as methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, tert-butyl acetoacetate; ethyl propionyl acetate, ethyl propionyl acetate, isopropyl propionyl acetate, propionyl acetate propionyl acetates such as tert-butyl; isobutyryl acetates such as ethyl isobutyryl acetate, ethyl isobutyryl acetate, isopropyl isobutyryl acetate, tert-butyl isobutyryl acetate; malonic acid esters such as methyl malonate and ethyl malonate; etc. And the like. Among these, acetylacetone and acetoacetic acid esters are preferable compounds. Such compounds producing keto-enol tautomerism may be used alone or in combination of two or more.

The amount of the compound that generates keto-enol tautomerism can be, for example, 0.1 to 20 parts by mass with respect to 100 parts by mass of the polymer (A), and usually 0.5 to 15 parts by mass. It is appropriate to use a mass part (for example, 1 to 10 parts by mass). If the amount of the compound is too small, it may be difficult to achieve a sufficient use effect. On the other hand, if the compound is used more than necessary, it may remain in the pressure-sensitive adhesive layer and reduce the cohesive force.

[Adhesive layer and adhesive sheet]
Then, the structure of the adhesive sheet which has an adhesive layer containing the adhesive composition which has the above-mentioned composition is demonstrated.

The pressure-sensitive adhesive layer can be a cured layer of the pressure-sensitive adhesive composition. That is, the pressure-sensitive adhesive layer can be formed by applying a pressure-sensitive adhesive composition to a suitable support (for example, coating / coating) and then appropriately performing a curing treatment. In the case where the support is a plastic substrate subjected to an antistatic treatment, an adhesive layer can be formed on the antistatic layer, or an adhesive layer can be formed on the surface not subjected to the antistatic treatment. When performing 2 or more types of hardening processes (drying, bridge | crosslinking, superposition | polymerization, etc.), these can be performed simultaneously or in multiple steps. In a pressure-sensitive adhesive composition using a partial polymer (acrylic polymer syrup), typically, as the curing treatment, a final copolymerization reaction is performed (the partial polymer is subjected to a further copolymerization reaction). A complete polymer is formed). For example, if it is a photocurable adhesive composition, light irradiation is implemented. If necessary, curing treatment such as cross-linking and drying may be performed. For example, when it is necessary to dry with a photocurable adhesive composition, it is good to perform photocuring after drying. In the pressure-sensitive adhesive composition using a completely polymerized product, typically, as the curing treatment, treatments such as drying (heat drying) and crosslinking are performed as necessary.

Application and coating of the pressure-sensitive adhesive composition can be carried out using a conventional coater such as a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, spray coater, etc. it can. The pressure-sensitive adhesive composition may be directly applied to the support to form a pressure-sensitive adhesive layer, or the pressure-sensitive adhesive layer formed on the release liner may be transferred to the support.

The pressure-sensitive adhesive layer has a solvent-insoluble component ratio of 85.00 mass% to 99.95 mass%, preferably 90.00 mass% to 99.95 mass%. When the solvent-insoluble component ratio is less than 85.00% by mass, the cohesive force becomes insufficient, which may cause contamination when peeled off from the adherend (protected body), and the solvent-insoluble component ratio is 99.95 mass%. If it exceeds 50%, the cohesive force becomes too high and the adhesive strength (high speed peel force, low speed peel force) may be inferior. In addition, the evaluation method of a solvent insoluble component rate is mentioned later.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, but usually good adhesiveness can be realized by setting the thickness to, for example, 3 μm to 60 μm, preferably 5 μm to 40 μm. When the thickness of the pressure-sensitive adhesive layer is less than 3 μm, adhesion may be insufficient and floating or peeling may occur. On the other hand, when the thickness of the pressure-sensitive adhesive layer exceeds 60 μm, the high-speed peeling force increases and the peeling workability decreases. There is.

The pressure-sensitive adhesive sheet according to this embodiment includes a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive composition. The pressure-sensitive adhesive sheet is provided with such a pressure-sensitive adhesive layer fixedly on at least one side of the support, that is, without intending to separate the pressure-sensitive adhesive layer from the support. The concept of the pressure-sensitive adhesive sheet referred to here may include what are called pressure-sensitive adhesive tapes, pressure-sensitive adhesive films, pressure-sensitive adhesive labels, and the like. Further, it may be cut into a suitable shape, punched out, or the like according to the intended use. The pressure-sensitive adhesive layer is not limited to those formed continuously, and may be a pressure-sensitive adhesive layer formed in a regular or random pattern such as a dot shape or a stripe shape.

As the support, for example,
Polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer Polyolefin films such as polymers, ethylene / vinyl alcohol copolymers, polyester films such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyacrylate films, polystyrene films, nylon 6, nylon 6,6, partially aromatic polyamides, etc. Plastic films such as polyamide film, polyvinyl chloride film, polyvinylidene chloride film, polycarbonate film;
Foam substrates such as polyurethane foam and polyethylene foam;
Kraft paper, crepe paper, Japanese paper, etc .;
Cotton, soft cloth, etc .;
Nonwoven fabrics such as polyester nonwoven fabrics and vinylon nonwoven fabrics;
Metal foil such as aluminum foil and copper foil;
Can be appropriately selected and used depending on the application of the adhesive tape. When the pressure-sensitive adhesive sheet of this embodiment is used as a surface protective sheet to be described later, it is preferable to use a plastic film such as a polyolefin film, a polyester film, or a polyvinyl chloride film as the support. In particular, when used as an optical surface protective sheet, it is preferable to use a polyolefin film, a polyethylene terephthalate film, a polybutylene terephthalate film, or a polyethylene naphthalate film. As the plastic film, any of an unstretched film and a stretched (uniaxially stretched or biaxially stretched) film can be used.

In addition, the support may be released with a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, silica powder, etc., and antifouling treatment, acid treatment, alkali treatment, primer treatment. Further, easy adhesion treatment such as corona treatment, plasma treatment, and ultraviolet treatment can be performed. The thickness of the support can be appropriately selected depending on the purpose, but is generally about 5 μm to 200 μm (typically 10 μm to 100 μm).

For the above-mentioned support, if necessary, silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, release with silica powder and antifouling treatment, acid treatment, alkali treatment, primer treatment, Anti-adhesive treatment such as corona treatment, plasma treatment and ultraviolet treatment, coating type, kneading type, vapor deposition type and the like can also be carried out.

Also, the plastic film used for the adhesive sheet is more preferably antistatic treated. By carrying out the antistatic treatment, the generation of static electricity can be prevented, which is useful in the technical fields related to optical and electronic components where charging becomes a particularly serious problem. The antistatic treatment applied to the plastic film is not particularly limited, and a method of providing an antistatic layer on at least one surface of a generally used film or a method of kneading a kneading type antistatic agent into the plastic film is used. As a method of providing an antistatic layer on at least one surface of the film, an antistatic resin comprising an antistatic agent and a resin component, a conductive polymer, a method of applying a conductive resin containing a conductive material, or a conductive material is deposited. Or the method of plating is mentioned.

Antistatic agents contained in the antistatic resin include cationic antistatic agents having cationic functional groups such as quaternary ammonium salts, pyridinium salts, primary, secondary and tertiary amino groups, and sulfonates. An anionic antistatic agent having an anionic functional group such as sulfate salt, phosphonate, phosphate ester salt, amphoteric antistatic agent such as alkylbetaine and its derivatives, imidazoline and its derivatives, alanine and its derivatives, Nonionic antistatic agents such as aminoalcohol and derivatives thereof, glycerin and derivatives thereof, polyethylene glycol and derivatives thereof, and monomers having an ion conductive group of the above cation type, anion type and zwitterionic type are polymerized or An ion conductive polymer obtained by copolymerization may be mentioned. These compounds may be used alone or in combination of two or more.

Specifically, as a cation type antistatic agent, for example, quaternary ammonium group such as alkyltrimethylammonium salt, acyloylamidopropyltrimethylammonium methosulfate, alkylbenzylmethylammonium salt, acylcholine chloride, polydimethylaminoethyl methacrylate, etc. (Meth) acrylate copolymer having quaternary, styrene copolymer having quaternary ammonium group such as polyvinylbenzyltrimethylammonium chloride, diallylamine copolymer having quaternary ammonium group such as polydiallyldimethylammonium chloride, and the like. These compounds may be used alone or in combination of two or more.

Examples of the anionic antistatic agent include alkyl sulfonate, alkyl benzene sulfonate, alkyl sulfate ester salt, alkyl ethoxy sulfate ester salt, alkyl phosphate ester salt, and sulfonate group-containing styrene copolymer. These compounds may be used alone or in combination of two or more.

Examples of zwitterionic antistatic agents include alkylbetaines, alkylimidazolium betaines, and carbobetaine graft copolymers. These compounds may be used alone or in combination of two or more.

Nonionic antistatic agents include, for example, fatty acid alkylolamide, di (2-hydroxyethyl) alkylamine, polyoxyethylene alkylamine, fatty acid glycerin ester, polyoxyethylene glycol fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid Examples include esters, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl ethers, polyethylene glycols, polyoxyethylene diamines, copolymers composed of polyethers, polyesters and polyamides, and methoxypolyethylene glycol (meth) acrylates. These compounds may be used alone or in combination of two or more.

Examples of the conductive polymer include polyaniline, polypyrrole, and polythiophene.

Examples of the conductive material include tin oxide, antimony oxide, indium oxide, cadmium oxide, titanium oxide, zinc oxide, indium, tin, antimony, gold, silver, copper, aluminum, nickel, chromium, titanium, iron, cobalt, Examples include copper iodide, and alloys or mixtures thereof.

General-purpose resins such as polyester, acrylic, polyvinyl, urethane, melamine, and epoxy are used as the resin component used for the antistatic resin and the conductive resin. In the case of a polymer type antistatic agent, it is not necessary to contain a resin component. Further, the antistatic resin component can contain a methylol- or alkylol-containing melamine-based, urea-based, glyoxal-based, acrylamide-based compound, epoxy compound, or isocyanate-based compound as a crosslinking agent.

The antistatic layer can be formed by, for example, diluting the antistatic resin, conductive polymer, or conductive resin with a solvent such as an organic solvent or water, and applying and drying the coating liquid on a plastic film. Is done.

Examples of the organic solvent used for forming the antistatic layer include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexanone, n-hexane, toluene, xylene, methanol, ethanol, n-propanol, and isopropanol. Can be mentioned. These solvents may be used alone or in combination of two or more.

As a coating method in forming the antistatic layer, a known coating method is appropriately used. Specifically, for example, roll coating, gravure coating, reverse coating, roll brush, spray coating, air knife coating, impregnation and The curtain coat method is mentioned.

The thickness of the antistatic resin layer, the conductive polymer, and the conductive resin is usually about 0.01 μm to 5 μm, preferably about 0.03 μm to 1 μm.

Examples of the method for depositing or plating the conductive material include vacuum deposition, sputtering, ion plating, chemical vapor deposition, spray pyrolysis, chemical plating, and electroplating.

The thickness of the conductive material layer is usually 2 nm to 1000 nm, preferably 5 nm to 500 nm.

Further, as the kneading type antistatic agent, the above antistatic agent is appropriately used. The mixing amount of the kneading type antistatic agent is 20% by mass or less, preferably 0.05% by mass to 10% by mass with respect to the total weight of the plastic film. The kneading method is not particularly limited as long as the antistatic agent can be uniformly mixed with the resin used for the plastic film. For example, a heating roll, a Banbury mixer, a pressure kneader, a biaxial kneader or the like is used. It is done.

In the pressure-sensitive adhesive sheet of the present embodiment, the surface protective sheet described later, and the optical surface protective sheet, a release liner can be bonded to the surface of the pressure-sensitive adhesive layer as needed to protect the pressure-sensitive adhesive surface.

The material constituting the release liner includes paper and plastic film, but a plastic film is preferably used because of its excellent surface smoothness. The film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. For example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer Examples thereof include a coalesced film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

The thickness of the release liner is usually about 5 μm to 200 μm, preferably about 10 μm to 100 μm. It is preferable for it to be in the above-mentioned range since it is excellent in workability for bonding to the pressure-sensitive adhesive layer and workability for peeling from the pressure-sensitive adhesive layer. For the release liner, if necessary, release and antifouling treatment with silicone, fluorine, long chain alkyl or fatty acid amide release agent, silica powder, etc., coating type, kneading type, vapor deposition An antistatic treatment such as a mold can also be performed.

The pressure-sensitive adhesive sheet has such characteristics that the adhesive strength at the time of high-speed peeling is small, and the adhesive strength at the time of low-speed peeling is sufficiently high so as not to cause a problem such as floating or peeling. The adhesive strength at the time of high-speed peeling of the pressure-sensitive adhesive sheet can be evaluated by a 180 ° peeling adhesive strength test when peeled at a tensile speed of 30 m / min and a peeling angle of 180 °, particularly 4.0 N / 25 mm or less. Is considered good. 180 degree peeling adhesive force becomes like this. Preferably it is 3.5 N / 25mm or less, More preferably, it is 3.0 N / 25mm or less. Further, the lower limit value of the 180 ° peeling adhesive strength is not particularly required, but is usually 0.1 N / 25 mm or more, preferably 0.2 N / 25 mm or more. The 180 ° peel adhesion test is measured according to the method and conditions described in the examples described later.

Further, the adhesive strength at the time of low-speed peeling of the pressure-sensitive adhesive sheet can be evaluated by a 180 ° peeling adhesive strength test when peeled at a tensile speed of 0.3 m / min and a peeling angle of 180 °, particularly 0.05 N / 25 mm. If it is above, it is judged to be good. 180 degree peeling adhesive force becomes like this. Preferably it is 0.06 N / 25mm or more, More preferably, it is 0.07 N / 25mm or more. Further, the upper limit value of the 180 ° peeling adhesive strength is not particularly required, but is usually 0.7 N / 25 mm or less, preferably 0.5 N / 25 mm or less. The 180 ° peel adhesion test is measured according to the method and conditions described in the examples described later.

Further, the adhesive strength at the time of low-speed peeling of the pressure-sensitive adhesive sheet can be further evaluated as the time required for peeling by a constant load peeling test, and a pressure of 1.2 g is 90 ° for a pressure-sensitive adhesive sheet width of 10 mm and a length of 50 mm. If the peeling time when loaded in the direction is 100 seconds or more, it is judged as good. The peeling time in the constant load peeling test is preferably 110 seconds or more, more preferably 120 seconds or more. The upper limit value of the peeling time in the constant load peeling test is not particularly required, but is usually 5000 seconds or less. The detailed conditions of the constant load peel test are measured according to the methods and conditions described in the examples described later.

Furthermore, the adhesive sheet has a characteristic of high transparency. The transparency of the pressure-sensitive adhesive sheet can be evaluated by haze. In particular, if the haze is less than 7%, it is judged good. The haze is preferably less than 5%, more preferably less than 3.5%. The detailed conditions of haze measurement are measured according to the methods and conditions described in the examples described later.

[Surface protection sheet]
As described above, the pressure-sensitive adhesive sheet has a low adhesive strength at the time of high-speed peeling, and has a high adhesive strength at the time of low-speed peeling to the extent that it does not cause problems such as floating and peeling, so that it protects the surface of various protected objects. It is preferable to use it as a protective sheet. Examples of the protection target to which the surface protection sheet can be applied include PE (polyethylene), PP (polypropylene), ABS (acrylonitrile-butadiene-styrene copolymer), SBS (styrene-butadiene-styrene block copolymer), PC ( Automobiles using various resins including acrylic resins such as polycarbonate (polycarbonate), PVC (vinyl chloride), and PMMA (polymethyl methacrylate resin), metals such as SUS (stainless steel) and aluminum, and glass. (The body coating film), housing materials, home appliances, and the like.

When using an adhesive sheet as a surface protection sheet, the above-mentioned adhesive sheet can be used as it is. However, particularly when used as a surface protection sheet, it is preferable to use a polyolefin film, a polyester film, or a polyvinyl chloride film having a thickness of 10 to 100 μm from the viewpoint of prevention of scratches and dirt and processability. The thickness of the pressure-sensitive adhesive layer is preferably about 3 μm to 60 μm.

[Optical surface protection sheet]
Furthermore, the surface protective sheet is preferably used as an optical surface protective sheet used for protecting the surface of an optical film, in addition to the above-mentioned adhesive properties, in particular because of its high transparency. Optical films to which optical surface protection sheets can be applied include polarizing plates, wave plates, optical compensation films, light diffusion sheets, reflection sheets, and antireflections used in image display devices such as liquid crystal displays, plasma displays, and organic EL displays. A sheet, a brightness enhancement film, a transparent conductive film (ITO film), etc. can be mentioned.

Optical surface protection sheet protects the optical film when the optical film manufacturer such as the polarizing plate is shipped, or the manufacturing process of the display device (liquid crystal module) when manufacturing the image display device such as a liquid crystal display device. The optical film can be used for protecting optical films in various processes such as punching and cutting.

When using the adhesive sheet as an optical surface protective sheet, the above-mentioned adhesive sheet can be used as it is. However, particularly when used as an optical surface protection sheet, the support is a polyolefin film of 10 μm to 100 μm, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyethylene naphthalate film from the viewpoint of prevention of scratches and dirt, processability, and transparency. Is preferably used. The thickness of the pressure-sensitive adhesive is preferably about 3 μm to 40 μm.

[Optical film with surface protection sheet]
Moreover, the optical film with a surface protection sheet by which the surface protection sheet for optics is stuck on the said optical film is provided. The optical film with a surface protective sheet is obtained by pasting the above optical surface protective sheet on one side or both sides of the optical film. When the optical film with a surface protective sheet is shipped in an optical film manufacturer such as the above polarizing plate, or in the manufacturing process of a display device (liquid crystal module) in an image display device manufacturer such as a liquid crystal display device, Further, in various processes such as punching and cutting, it is possible to prevent the optical film from being scratched or adhering to dust or dirt. Moreover, since the optical surface protection sheet has high transparency, it is possible to carry out the inspection as it is. Furthermore, when it becomes unnecessary, the optical surface protective sheet can be easily peeled without damaging the optical film or the image display device.

As described above, the pressure-sensitive adhesive composition according to the present embodiment has 100 parts by mass of the polymer (A) having a glass transition temperature of less than 0 ° C. as the pressure-sensitive adhesive composition, and a weight average molecular weight of 1000 or more and less than 30000, 0.05 part by mass of a (meth) acrylic polymer (B) containing a (meth) acrylic monomer having an alicyclic structure, a monomer having a polyoxyalkylene skeleton, and a monomer having a polyorganosiloxane skeleton as monomer units By including 20 parts by mass, when the pressure-sensitive adhesive composition is used to form a pressure-sensitive adhesive layer, the pressure-sensitive adhesive force at the time of high-speed peeling is small, and the low-speed peeling is performed so as not to cause problems such as lifting and peeling. The adhesive strength at the time can be increased. Due to such excellent characteristics, the pressure-sensitive adhesive sheet provided with a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive composition can be used as a surface protection sheet, and in particular, the surface for an optical film used for surface protection of an optical film. Used as a protection sheet. It can also be used as an optical film with a surface protective sheet in which an optical surface protective sheet is attached to an optical film.

The reason why the pressure-sensitive adhesive sheet was able to sufficiently increase the adhesive force during low-speed peeling to such an extent that the adhesive force during high-speed peeling from the adherend was small and did not cause problems such as lifting or peeling was Monomer having a monomer having an oxyalkylene chain and a (meth) acrylic monomer having an alicyclic structure as a monomer unit and having a polyorganosiloxane skeleton capable of adjusting the bleeding property to the adherend interface By adding the (meth) acrylic polymer contained as a unit and adding a small amount of added parts, the adhesiveness at the time of low-speed peeling is greatly affected, and at the same time, excellent peeling at high-speed peeling is achieved. It is presumed that it became possible to obtain sex.

Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited to these examples.

Table 1 shows components of the pressure-sensitive adhesive compositions according to Examples 1 to 6 and Comparative Examples 1 to 3.

Abbreviations in Table 1 indicate the following compounds.
2EHA: 2-ethylhexyl acrylate HEA: 2-hydroxyethyl acrylate DCPMA: dicyclopentanyl methacrylate MMA: methyl methacrylate IBXMA: isobornyl methacrylate CHMA: cyclohexyl methacrylate

(Adjustment of acrylic polymer (A) (2EHA / HEA = 96/4))
In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas introduction tube, condenser, and dropping funnel, 96 parts by mass of 2-ethylhexyl acrylate (2EHA), 4 parts by mass of 2-hydroxyethyl acrylate (HEA), As a polymerization initiator, 0.22 parts by mass of 2,2′-azobisisobutyronitrile and 150 parts by mass of ethyl acetate were charged, nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was around 65 ° C. Then, a polymerization reaction was carried out for 6 hours to prepare an acrylic polymer (A) solution (40% by mass). The acrylic polymer (A) had a glass transition temperature calculated from the Fox equation of −68 ° C. and a weight average molecular weight of 550,000.

(Preparation of (meth) acrylic polymer 1 (DCPMA / PME-1000 / X-22-2475 = 10/35/55) as component (B))
50 parts by mass of ethyl acetate, 50 parts by mass of toluene, 10 parts by mass of dicyclopentanyl methacrylate (DCPMA) (trade name: FA-513M, manufactured by Hitachi Chemical Co., Ltd.), and the average number of added moles of oxyethylene units is 23 35 parts by mass of methoxypolyethylene glycol methacrylate (trade name: Blenmer PME-1000, manufactured by NOF Corporation), 55 parts by mass of methacrylate monomer containing organopolysiloxane skeleton (trade name: X-22-2475, manufactured by Shin-Etsu Chemical Co., Ltd.) As a chain transfer agent, 3 parts by mass of methyl thioglycolate was charged into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, a cooler, and a dropping funnel. Then, after stirring at 70 ° C. for 1 hour in a nitrogen atmosphere, 0.2 part by mass of azobisisobutyronitrile as a thermal polymerization initiator was added and reacted at 70 ° C. for 2 hours. Reacted for hours. The obtained (meth) acrylic polymer 1 had a weight average molecular weight of 4,100.

(Preparation of (meth) acrylic polymer 2 (IBXMA / PME-1000 / X-22-2475 = 30/30/40) as component (B))
50 parts by mass of ethyl acetate, 50 parts by mass of toluene, 30 parts by mass of isobornyl methacrylate (IBXMA), methoxypolyethylene glycol methacrylate having an average addition mole number of oxyethylene units of 23 (trade name: Blemmer PME-1000, NOF Corporation) 30 parts by mass), 40 parts by mass of an organopolysiloxane skeleton-containing methacrylate monomer (trade name: X-22-2475, manufactured by Shin-Etsu Chemical Co., Ltd.) and 3 parts by mass of methyl thioglycolate as a chain transfer agent The solution was put into a four-necked flask equipped with a thermometer, a nitrogen gas introduction tube, a cooler, and a dropping funnel. Then, after stirring at 70 ° C. for 1 hour in a nitrogen atmosphere, 0.2 part by mass of azobisisobutyronitrile as a thermal polymerization initiator was added and reacted at 70 ° C. for 2 hours. Reacted for hours. The obtained (meth) acrylic polymer 2 had a weight average molecular weight of 4000.

(Preparation of (meth) acrylic polymer 3 (CHMA / PME-1000 / X-22-2475 = 30/30/40) as component (B))
50 parts by mass of ethyl acetate, 50 parts by mass of toluene, 30 parts by mass of cyclohexyl methacrylate (CHMA), methoxypolyethylene glycol methacrylate having an average addition mole number of oxyethylene units of 23 (trade name: Blemmer PME-1000, manufactured by NOF Corporation) ) 30 parts by mass, 40 parts by mass of an organopolysiloxane skeleton-containing methacrylate monomer (trade name: X-22-2475, manufactured by Shin-Etsu Chemical Co., Ltd.) and 3 parts by mass of methyl thioglycolate as a chain transfer agent, stirring blade, thermometer , A four-necked flask equipped with a nitrogen gas inlet tube, a cooler, and a dropping funnel. Then, after stirring at 70 ° C. for 1 hour in a nitrogen atmosphere, 0.2 part by mass of azobisisobutyronitrile as a thermal polymerization initiator was added and reacted at 70 ° C. for 2 hours. Reacted for hours. The weight average molecular weight of the obtained (meth) acrylic polymer 3 was 4700.

(Meth) acrylic polymer 4 as component (B) (preparation of DCPMA / PME-1000 / X-22-2475 / X-22-174DX = 24/28/38/10)
50 parts by mass of ethyl acetate, 50 parts by mass of toluene, 24 parts by mass of dicyclopentanyl methacrylate (DCPMA) (trade name: FA-513M, manufactured by Hitachi Chemical Co., Ltd.), and the average added mole number of oxyethylene units is 23 28 parts by mass of methoxypolyethylene glycol methacrylate (trade name: Blemmer PME-1000, manufactured by NOF Corporation), 38 parts by mass of methacrylate monomer containing organopolysiloxane skeleton (trade name: X-22-2475, manufactured by Shin-Etsu Chemical Co., Ltd.) 10 parts by mass of an organopolysiloxane skeleton-containing methacrylate monomer (trade name: X-22-174DX, manufactured by Shin-Etsu Chemical Co., Ltd.) and 3 parts by mass of methyl thioglycolate as a chain transfer agent, stirring blade, thermometer, nitrogen gas introduction Four-necked hula with tube, cooler, and dropping funnel They were placed in a call. Then, after stirring at 70 ° C. for 1 hour in a nitrogen atmosphere, 0.2 part by mass of azobisisobutyronitrile as a thermal polymerization initiator was added and reacted at 70 ° C. for 2 hours. Reacted for hours. The obtained (meth) acrylic polymer 4 had a weight average molecular weight of 4000.

((Meth) acrylic polymer 5 as component (B) (preparation of DCPMA / MMA / PME-1000 / X-22-174DX = 40/10/25/25)
50 parts by mass of ethyl acetate, 50 parts by mass of toluene, 40 parts by mass of dicyclopentanyl methacrylate (DCPMA) (trade name: FA-513M, manufactured by Hitachi Chemical Co., Ltd.), 10 parts by mass of methyl methacrylate (MMA), oxyethylene unit 25 parts by mass of methoxypolyethylene glycol methacrylate (trade name: Blemmer PME-1000, manufactured by NOF Corporation) having an average addition mole number of 23, organopolysiloxane skeleton-containing methacrylate monomer (trade name: X-22-174DX, Shin-Etsu) 25 parts by mass of Chemical Industry Co., Ltd.) and 3 parts by mass of methyl thioglycolate as a chain transfer agent were charged into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, a cooler, and a dropping funnel. Then, after stirring at 70 ° C. for 1 hour in a nitrogen atmosphere, 0.2 part by mass of azobisisobutyronitrile as a thermal polymerization initiator was added and reacted at 70 ° C. for 2 hours. Reacted for hours. The obtained (meth) acrylic polymer 5 had a weight average molecular weight of 4,500.

((Meth) acrylic polymer 6 as component (B) (preparation of DCPMA / MMA / PME-1000 / X-22-2475 = 20/5/20/55)
50 parts by mass of ethyl acetate, 50 parts by mass of toluene, 20 parts by mass of dicyclopentanyl methacrylate (DCPMA) (trade name: FA-513M, manufactured by Hitachi Chemical Co., Ltd.), 5 parts by mass of methyl methacrylate (MMA), oxyethylene unit 20 parts by mass of methoxypolyethylene glycol methacrylate (trade name: Blemmer PME-1000, manufactured by NOF Corporation) having an average addition mole number of 23, organopolysiloxane skeleton-containing methacrylate monomer (trade name: X-22-2475) ( 55 parts by mass (manufactured by Shin-Etsu Chemical Co., Ltd.) and 3 parts by mass of methyl thioglycolate as a chain transfer agent were charged into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, a cooler, and a dropping funnel. Then, after stirring at 70 ° C. for 1 hour in a nitrogen atmosphere, 0.2 part by mass of azobisisobutyronitrile as a thermal polymerization initiator was added and reacted at 70 ° C. for 2 hours. Reacted for hours. The weight average molecular weight of the obtained (meth) acrylic polymer 6 was 4000.

(Preparation of (meth) acrylic polymer 7 (DCPMA / MMA / PME-200 = 40/10/50) as component (B))
100 parts by mass of ethyl acetate, 40 parts by mass of dicyclopentanyl methacrylate (DCPMA) (trade name: FA-513M, manufactured by Hitachi Chemical Co., Ltd.), 10 parts by mass of methyl methacrylate (MMA), average added mole number of oxyethylene units Is 50 parts by mass of methoxypolyethylene glycol methacrylate (trade name: Blenmer PME-200, manufactured by NOF Corporation) and 3 parts by mass of methyl thioglycolate as a chain transfer agent, a stirring blade, a thermometer, a nitrogen gas introduction tube, A four-necked flask equipped with a condenser and a dropping funnel was charged. Then, after stirring at 70 ° C. for 1 hour in a nitrogen atmosphere, 0.2 part by mass of azobisisobutyronitrile as a thermal polymerization initiator was added and reacted at 70 ° C. for 2 hours. Reacted for hours. The obtained (meth) acrylic polymer 7 had a weight average molecular weight of 5,000.

(Preparation of (meth) acrylic polymer 8 (DCPMA / MMA / PME-1000 = 40/10/50) as component (B))
100 parts by mass of ethyl acetate, 40 parts by mass of dicyclopentanyl methacrylate (DCPMA) (trade name: FA-513M, manufactured by Hitachi Chemical Co., Ltd.), 10 parts by mass of methyl methacrylate (MMA), average added mole number of oxyethylene units Is 50 parts by mass of methoxypolyethylene glycol methacrylate (trade name: Blenmer PME-1000, manufactured by NOF Corporation) and 3 parts by mass of methyl thioglycolate as a chain transfer agent, a stirring blade, a thermometer, a nitrogen gas introduction tube, A four-necked flask equipped with a condenser and a dropping funnel was charged. Then, after stirring at 70 ° C. for 1 hour in a nitrogen atmosphere, 0.2 part by mass of azobisisobutyronitrile as a thermal polymerization initiator was added and reacted at 70 ° C. for 2 hours. Reacted for hours. The obtained (meth) acrylic polymer 8 had a weight average molecular weight of 5,500.

(Example 1)
(Preparation of adhesive composition)
(Meth) acrylic polymer 1 was added to 500 parts by mass (acrylic polymer (A) 100 parts by mass) of an acrylic polymer (A). The solution (35% by mass) diluted to 20% by mass with ethyl acetate. 1 part by mass, 0.2 part by mass of 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide (Daiichi Kogyo Seiyaku Co., Ltd., AS-110) as an ionic liquid, and Coronate L (manufactured by Polyurethane Industry Co., Ltd.) as a crosslinking agent , Trimethylolpropane / tolylene diisocyanate trimer adduct solids 75% by weight solution), 3.3 parts by weight, and 3 parts by weight of dioctyltin dilaurate in ethyl acetate (1% by weight) as a crosslinking catalyst. A pressure-sensitive adhesive composition (1) was prepared by mixing and stirring at 25 ° C. for about 5 minutes.

(Preparation of adhesive sheet)
The pressure-sensitive adhesive composition (1) was applied to the surface opposite to the antistatic surface of the polyethylene terephthalate film with an antistatic layer (trade name: Diafoil T100G38, manufactured by Mitsubishi Plastics, Inc., thickness 38 μm), The mixture was heated at 130 ° C. for 2 minutes to form a pressure-sensitive adhesive layer having a thickness of 15 μm. Next, a silicone-treated surface of a release liner (25 μm thick polyethylene terephthalate film having a silicone treatment on one side) was bonded to the surface of the pressure-sensitive adhesive layer to produce a pressure-sensitive adhesive sheet.

(Example 2)
(Preparation of adhesive composition)
Instead of using 1 part by mass of the (meth) acrylic polymer 1, 0.35 parts by mass of the (meth) acrylic polymer 2 was used, and the 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) was used. ) Imido (Daiichi Kogyo Seiyaku Co., Ltd., AS-110) Instead of using 0.2 parts by mass, 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide (Daiichi Kogyo Seiyaku Co., Ltd., AS -110) Instead of using 0.1 parts by mass of Coronate L and 3.3 parts by mass of Coronate L, 1.5 parts by mass of Coronate HX (made by Nippon Polyurethane Industry Co., Ltd., isocyanurate type hexamethylene diisocyanate crosslinking agent) A pressure-sensitive adhesive composition (2) was prepared in the same manner as in Example 1 except that it was used.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive composition (2) was used in place of the pressure-sensitive adhesive composition (1).

(Example 3)
(Preparation of adhesive composition)
In place of using 0.35 parts by mass of (meth) acrylic polymer 2 above, 0.35 parts by mass of (meth) acrylic polymer 3 was used. An agent composition (3) was prepared.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive composition (3) was used in place of the pressure-sensitive adhesive composition (1).

Example 4
(Preparation of adhesive composition)
Instead of using 1 part by mass of the (meth) acrylic polymer 1, 0.25 part by mass of the (meth) acrylic polymer 4 is used, and the 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) is used. ) Instead of using 0.2 parts by mass of imide (Daiichi Kogyo Seiyaku Co., Ltd., AS-110), 0.06 parts by mass of bis (trifluoromethanesulfonyl) imide lithium (manufactured by Tokyo Chemical Industry Co., Ltd., LiTFSI) was used. Example 1 except that 1.2 parts by mass of Coronate HX (manufactured by Nippon Polyurethane Industry Co., Ltd., isocyanurate type hexamethylene diisocyanate crosslinking agent) was used instead of 3.3 parts by mass of Coronate L. In the same manner as above, a pressure-sensitive adhesive composition (4) was prepared.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive composition (4) was used instead of the pressure-sensitive adhesive composition (1).

(Example 5)
(Preparation of adhesive composition)
Instead of using 1 part by mass of the (meth) acrylic polymer 1, the 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide is used by using 1 part by mass of the (meth) acrylic polymer 5. (Instead of using 0.2 parts by mass (AS-110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), 0.03 parts by mass of bis (trifluoromethanesulfonyl) imidolithium (manufactured by Tokyo Chemical Industry Co., Ltd., LiTFSI) is used. A pressure-sensitive adhesive composition (5) was prepared in the same manner as in Example 1 except that 3.3 parts by mass of coronate L was used and 2 parts by mass of coronate L was used.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive composition (5) was used in place of the pressure-sensitive adhesive composition (1).

(Example 6)
(Preparation of adhesive composition)
Instead of using 1 part by mass of the (meth) acrylic polymer 1, the 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide is used by using 1 part by mass of the (meth) acrylic polymer 6. Instead of using 0.2 parts by mass (AS-110 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), 0.03 parts by mass of bis (trifluoromethanesulfonyl) imide lithium (manufactured by Tokyo Chemical Industry Co., Ltd., LiTFSI) was used. Except for this, a pressure-sensitive adhesive composition (6) was prepared in the same manner as in Example 1.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive composition (6) was used in place of the pressure-sensitive adhesive composition (1).

(Comparative Example 1)
(Preparation of adhesive composition)
Instead of using 1 part by mass of the (meth) acrylic polymer 5, the pressure-sensitive adhesive composition (in the same manner as in Example 5 except that 1 part by mass of the (meth) acrylic polymer 7 was used) 7) was prepared.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive composition (7) was used in place of the pressure-sensitive adhesive composition (1).

(Comparative Example 2)
(Preparation of adhesive composition)
Instead of using 1 part by mass of the (meth) acrylic polymer 5 described above, the pressure-sensitive adhesive composition ( 8) was prepared.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive composition (8) was used in place of the pressure-sensitive adhesive composition (1).

(Comparative Example 3)
(Preparation of adhesive composition)
Instead of using 1 part by mass of the (meth) acrylic polymer 5, a polyether compound having a polyoxyalkylene chain [manufactured by Shin-Etsu Silicone Co., Ltd., trade name “KF-6004”, active ingredient 100% by mass A pressure-sensitive adhesive composition (9) was prepared in the same manner as in Example 5 except that 0.5 part by mass of the compound was used.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive composition (9) was used in place of the pressure-sensitive adhesive composition (1).

(Test method)
<Measurement of molecular weight>
The weight average molecular weight of the polymer and the (meth) acrylic copolymer was measured using a GPC apparatus (manufactured by Tosoh Corporation, HLC-8220 GPC). The measurement conditions were as follows, and the molecular weight was determined by standard polystyrene conversion.
Sample concentration: 0.2 wt% (tetrahydrofuran (THF) solution)
Sample injection volume: 10 μl
・ Eluent: THF
・ Flow rate: 0.6ml / min
・ Measurement temperature: 40 ℃
·column:
Sample column: TSKguardcolumn SuperHZ-H (1) + TSKgel SuperHZM-H (2)
Reference column; TSKgel SuperH-RC (1 piece)
・ Detector: Differential refractometer (RI)

(Measurement of solvent insoluble component ratio)
The solvent-insoluble component ratio was determined by sampling 0.1 g of the pressure-sensitive adhesive composition and precisely weighing it (mass before immersion), and immersing it in about 50 ml of ethyl acetate at room temperature (20 to 25 ° C.) for 1 week. The solvent (ethyl acetate) insoluble matter was taken out, and the solvent insoluble matter was dried at 130 ° C. for 2 hours, and then weighed (mass after soaking and drying) to calculate the solvent insoluble component rate calculation formula “solvent insoluble component rate (mass %) = [(Mass after soaking / drying) / (mass before soaking)] × 100 ”. Table 2 shows the measurement results of the solvent-insoluble component ratio.

(Low speed peel test: constant load peel)
The pressure-sensitive adhesive sheet according to each Example and Comparative Example was cut to a size of 10 mm in width and 60 mm in length, and after peeling off the release liner, a triacetyl cellulose polarizing plate (Nitto Denko Corporation, SEG1425DU, width: 70 mm, length: 100 mm) ) Was pressure-bonded to the surface with a hand roller and then laminated under pressure-bonding conditions of 0.25 MPa and 0.3 m / min to produce an evaluation sample (optical film with a surface protective sheet). After the above lamination, the substrate was left for 30 minutes in an environment of 23 ° C. × 50% RH, and then the opposite surface of the triacetyl cellulose polarizing plate 2 was fixed to the acrylic plate 4 with a double-sided adhesive tape 3 as shown in FIG. 5 (1.2 g) was fixed to one end of the pressure-sensitive adhesive sheet 1. The tape sample was started to peel off at a constant load so that the peeling angle was 90 °. A length of 10 mm was used as an extra length, and the time until all the remaining 50 mm length was peeled was measured. The measurement was performed in an environment of 23 ° C. × 50% RH. When the peeling time under a constant load was 100 seconds or more, it was judged as good (◯), and when it was less than 100 seconds, it was judged as bad (x). The measurement results are shown in Table 2.

(Low speed peel test: 180 ° peel adhesion)
After the pressure-sensitive adhesive sheet according to each Example and Comparative Example was cut to a size of 25 mm in width and 100 mm in length and the release liner was peeled off, a triacetyl cellulose polarizing plate (manufactured by Nitto Denko Corporation, SEG1425DU, width: 70 mm, length: 100 mm) was pressure-bonded with a hand roller and then laminated under pressure bonding conditions of 0.25 MPa and 0.3 m / min to prepare an evaluation sample (optical film with a surface protective sheet). After the above lamination, the substrate was left for 30 minutes in an environment of 23 ° C. × 50% RH, and then the opposite surface of the triacetyl cellulose polarizing plate 2 was fixed to the acrylic plate 4 with a double-sided adhesive tape 3 as shown in FIG. The pressure-sensitive adhesive force when one end of the pressure-sensitive adhesive sheet 1 was peeled off at a tensile speed of 0.3 m / min and a peeling angle of 180 ° was measured with a testing machine. The measurement was performed in an environment of 23 ° C. × 50% RH. Those having an adhesive strength at the time of low-speed peeling of 0.05 N / 25 mm or more were evaluated as good (◯), and those having an adhesive strength of less than 0.05 N / 25 mm were evaluated as poor (×). The measurement results are shown in Table 2.

(High speed peel test: 180 ° peel adhesion)
After the pressure-sensitive adhesive sheet according to each Example and Comparative Example was cut to a size of 25 mm in width and 100 mm in length and the release liner was peeled off, a triacetyl cellulose polarizing plate (manufactured by Nitto Denko Corporation, SEG1425DU, width: 70 mm, length: 100 mm) was pressure-bonded with a hand roller and then laminated under pressure bonding conditions of 0.25 MPa and 0.3 m / min to prepare an evaluation sample (optical film with a surface protective sheet). After the above lamination, the substrate was left for 30 minutes in an environment of 23 ° C. × 50% RH, and then the opposite surface of the triacetyl cellulose polarizing plate 2 was fixed to the acrylic plate 4 with a double-sided adhesive tape 3 as shown in FIG. The pressure-sensitive adhesive force when one end of the pressure-sensitive adhesive sheet 1 was peeled off at a tensile speed of 30 m / min and a peeling angle of 180 ° was measured with a testing machine. The measurement was performed in an environment of 23 ° C. × 50% RH. Those having an adhesive force of less than 3.0 N / 25 mm during high-speed peeling were judged as good (◯), and those of 4.0 N / 25 mm or more were judged as defective (x). The measurement results are shown in Table 2.

(Transparency test: haze)
After the adhesive sheet according to each example and comparative example was cut to a size of 50 mm in width and 50 mm in length, the release liner was peeled off, and haze was measured with a haze meter (manufactured by Murakami Color Research Laboratory Co., Ltd.). A haze of less than 7% was considered good, and a haze of 7% or more was judged bad. Table 2 shows the measurement results of haze.

As shown in Table 2, Comparative Examples 1 and 2 using a (meth) acrylic polymer (B) having a weight average molecular weight of 1000 or more and less than 30000, and not containing an organopolysiloxane skeleton-containing monomer as a monomer unit, It was confirmed that the adhesive strength during high-speed peeling was very high. Further, instead of using the (meth) acrylic polymer (B) having an alicyclic structure, a polyoxyalkylene skeleton, and a polyorganosiloxane skeleton, Comparative Example 3 using an organopolysiloxane having a polyoxyalkylene chain is It was confirmed that the adhesive strength at the time of low-speed peeling was not sufficient.

Further, in all of the examples, it was confirmed that both the adhesive force at high speed peeling and the adhesiveness at low speed peeling were compatible. Moreover, in all Examples, it was confirmed that transparency was favorable.

DESCRIPTION OF SYMBOLS 1 Adhesive sheet 2 Polarizing plate 3 Double-sided adhesive tape 4 Acrylic board 5 Constant load

The present invention is applicable to a pressure-sensitive adhesive composition, a pressure-sensitive adhesive layer and a pressure-sensitive adhesive sheet having the pressure-sensitive adhesive composition.

Claims

100 parts by weight of polymer (A) having a glass transition temperature of less than 0 ° C.,
A (meth) acrylic monomer having a weight average molecular weight of 1000 or more and less than 30000 and having an alicyclic structure represented by the following general formula (1), a monomer having a polyoxyalkylene skeleton, and a monomer having a polyorganosiloxane skeleton 0.05 to 20 parts by mass of (meth) acrylic polymer (B) containing
A pressure-sensitive adhesive composition comprising:
CH 2 = C (R 1 ) COOR 2 (1)
[In Formula (1), R 1 is a hydrogen atom or a methyl group, and R 2 is an alicyclic hydrocarbon group having an alicyclic structure]
The pressure-sensitive adhesive composition according to claim 1, wherein the polymer (A) is an acrylic polymer.
The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the alicyclic hydrocarbon group of the (meth) acrylic monomer having an alicyclic structure has a bridged ring structure.
The monomer having a polyoxyalkylene skeleton is an oxyalkylene group-containing monomer represented by the following general formula (2) and having an average addition mole number of oxyalkylene units of 3 to 40. The pressure-sensitive adhesive composition according to claim 1.

[In the formula (2), R 1 is hydrogen or a methyl group, R 2 is hydrogen or a monovalent organic group, m and p are integers of 2 to 4, and n and q are 0 or 2 to 40 Is an integer and n and q cannot be 0 at the same time]
5. The monomer according to claim 1, wherein the monomer having an organopolysiloxane skeleton is one or more monomers selected from a monomer group represented by the following general formula (3) or (4). The pressure-sensitive adhesive composition described.

[In the formulas (3) and (4), R 3 is hydrogen or methyl, R 4 is methyl or a monovalent organic group, and m and n are integers of 0 or more.]
The pressure-sensitive adhesive composition according to any one of claims 2 to 5, wherein the acrylic polymer further contains a hydroxyl group-containing (meth) acrylic monomer as a monomer component.
The acrylic polymer further contains, as a monomer component, 5.0% by mass or less of an oxyalkylene group-containing reactive monomer having an average addition mole number of oxyalkylene units of 3 to 40 as a monomer component. Item 2. The pressure-sensitive adhesive composition according to item 1.
A pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition according to any one of claims 1 to 7.
The pressure-sensitive adhesive layer according to claim 8, comprising 85.00 to 99.95% by mass of a solvent-insoluble component.
A pressure-sensitive adhesive sheet comprising the pressure-sensitive adhesive layer according to claim 9 formed on at least one side of a support.
The pressure-sensitive adhesive sheet according to claim 10, wherein the support is a plastic film subjected to an antistatic treatment.
A surface protective sheet comprising the pressure-sensitive adhesive sheet according to claim 10 or 11.
An optical surface protective sheet used for surface protection of an optical film, comprising the surface protective sheet according to claim 12.
An optical film with a surface protective sheet, wherein the optical surface protective sheet according to claim 13 is affixed to the optical film.