JP2016130270A - Adhesive composition, adhesive layer, adhesive sheet and optical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive that has an adhesive force low enough to be reworkable in an initial stage of sticking and that afterwards firmly adheres to an adherend and shows excellent transparency.SOLUTION: An adhesive composition is provided, which comprises 100 pts.mass of a polymer (A) having a glass transition temperature of lower than 0°C, 0.05 pts.mass to 50 pts.mass of a (meth)acrylic polymer (B) having a weight average molecular weight of 1000 or more and less than 30000 and containing a monomer having a polyoxyalkylene skeleton as a monomer unit, and 0.01 pts.mass to 40 pts.mass of a (meth)acrylic polymer (C) represented by general formula (1): CH=C(R)COORand having a glass transition temperature of 0°C or higher in a homopolymer state. In the formula (1), Rrepresents a hydrogen atom or a methyl group; and Rrepresents an alkyl group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group. The (meth)acrylic polymer (C) does not contain a polyoxyalkylene skeleton.SELECTED DRAWING: None

Description

  The present invention relates to a pressure-sensitive adhesive composition, and a pressure-sensitive adhesive layer, a pressure-sensitive adhesive sheet, and an optical film having the pressure-sensitive adhesive composition.

  The pressure-sensitive adhesive sheet is used for the purpose of bonding adherends to each other or fixing an article to the adherend by firmly adhering to the adherends. At this time, if the adhesive strength is higher than that in the initial stage of adhesion, it is difficult to reattach the adhesive. Therefore, there is a demand for an adhesive tape that has low adhesive strength at the initial stage but increases in adhesive strength with time and can provide high adhesive strength.

  Particularly in recent years, liquid crystal displays, plasma displays, organic EL displays and the like have become widespread. In these displays, it is indispensable to dispose various optical films on both sides of the glass substrate that forms the outermost surface. For example, a polarizing film is attached to the outermost surface of the liquid crystal panel. In addition, various optical elements have been used to improve the display quality of the display, for example, a retardation film as an anti-coloring film, a viewing angle widening film for improving the viewing angle of a liquid crystal display, Furthermore, a brightness enhancement film for increasing the contrast of the display is used. These films are collectively called optical films.

  When sticking the said optical film on the outermost surface of a display, an adhesive is normally used. In addition, since the optical film can be instantly fixed to the outermost surface of the display and has a merit such that a drying process is not required to fix the optical film, the adhesive is pre-adhesive layer on one side of the optical film. It is provided as. That is, an adhesive optical film is generally used for attaching the optical film to the outermost surface of the liquid crystal panel. As the pressure-sensitive adhesive, acrylic pressure-sensitive adhesives that are excellent in terms of adhesiveness, transparency, weather resistance and the like are frequently used.

  In addition, the pressure-sensitive adhesive used for adhering the optical film may be required to have a characteristic that it can be bonded (reworked). This is because when the optical film is bonded to the outermost surface of the display, the bonding position is often wrong, or foreign objects are often caught in the bonding surface. This is a characteristic required to enable bonding. In this case, since the display is expensive, it is reused, but the relatively inexpensive optical film is discarded.

  About the said rework property, the adhesive force with respect to the glass substrate of the outermost surface of a display needs to be lower. However, as displays become more widespread in various fields such as mobile phones, measuring instruments, electronic watches and televisions, and in-vehicle devices, the opportunities for use under harsh conditions increase. It is required that the adhesion via the pressure-sensitive adhesive layer has an adhesive strength that can sufficiently withstand use in a hot and humid atmosphere. Therefore, the adhesive strength is low enough to allow rework at the beginning of pasting, and after that, even in a hot and humid atmosphere, it adheres firmly so that it does not float or peel off at the interface between the adhesive layer and the display. An agent is desired.

  Moreover, high transparency was requested | required of adhesive itself as an adhesive used for sticking of an optical film.

  As an acrylic pressure-sensitive adhesive composition having sufficient adhesiveness and excellent removability and a pressure-sensitive adhesive sheet using the same, (A) an alkyl group having 8 to 13 carbon atoms. Acrylate having 100 parts by weight, (B) 10 to 90 parts by weight of acrylate having a saturated alicyclic group in the side chain, and (C) ethylene glycol chain or propylene glycol chain, the number of repetitions of which is 2 to 23 A pressure-sensitive adhesive composition containing 1 to 40 parts by mass of an acrylate, a polymerization initiator, and a crosslinking agent, and a pressure-sensitive adhesive sheet obtained by light irradiation of the pressure-sensitive adhesive composition have been proposed (see Patent Document 1).

JP 2008-195753 A

  Conventional pressure-sensitive adhesive sheets have been unsatisfactory because of their poor adhesive strength over time and poor adhesion reliability.

  The present invention has been made in view of these problems, and its purpose is to have a low adhesive strength to the extent that it can be reworked at the initial stage of bonding, and then firmly adheres to the adherend and is excellent in transparency. In providing adhesives.

One embodiment of the present invention is a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition contains, as a monomer unit, 100 parts by mass of a polymer (A) having a glass transition temperature of less than 0 ° C., a weight average molecular weight of 1,000 to less than 30000, and a monomer having a polyoxyalkylene skeleton as a monomer unit. (Meth) acrylic polymer (B) 0.05 parts by mass to 50 parts by mass and represented by the following general formula (1), including a (meth) acrylic monomer having a glass transition temperature of 0 ° C. or higher. 0.01 to 40 parts by mass of acrylic polymer (C),
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 alkyl group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group]
However, the (meth) acrylic polymer (C) does not contain a polyoxyalkylene skeleton.

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

一般式（Ｍ１）式中、Ｒ^１は、２価の有機基である。 In the pressure-sensitive adhesive composition of the above aspect, the acrylic polymer is further at least one selected from the group consisting of an N-vinyl cyclic amide represented by the following general formula (M1) and a hydroxyl group-containing monomer as a monomer unit. The monomer may be contained.

In the general formula (M1), R ¹ is a divalent organic group.

In the pressure-sensitive adhesive composition of the above aspect, R ^{2 of} the (meth) acrylic monomer constituting the (meth) acrylic polymer (C) may be an alicyclic hydrocarbon group.

［式中、Ｒ_１は水素またはメチル基であり、Ｒ_２は水素または１価の有機基であり、ｍおよびｐは２〜４の整数、ｎおよびｑは０または２〜４０の整数であり、ｎおよびｑが同時に０となることはない] In the pressure-sensitive adhesive composition of the above aspect, the (meth) acrylic polymer (B) has a polyoxyalkylene skeleton monomer represented by the following general formula (2), and an average addition mole number of oxyalkylene units. The oxyalkylene group containing monomer which is 3-40 may be sufficient.

[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]

  Another embodiment of the present invention is a pressure-sensitive adhesive layer. The said adhesive layer consists of an adhesive composition of any aspect mentioned above. In the pressure-sensitive adhesive layer of this embodiment, 55.0% by mass to 99.0% by mass of a solvent-insoluble component may be included.

  Yet another embodiment of the present invention is a pressure-sensitive adhesive sheet. The pressure-sensitive adhesive sheet includes the pressure-sensitive adhesive layer according to any one of the above-described aspects.

  According to the present invention, the pressure-sensitive adhesive composition is low enough to allow rework at the initial stage of bonding, and then firmly adheres to the adherend over time, has excellent adhesion reliability, and has excellent transparency, An adhesive layer, an adhesive sheet, and an optical sheet with an adhesive layer are provided.

The pressure-sensitive adhesive composition according to the embodiment includes, as a monomer unit, 100 parts by mass of a polymer (A) having a glass transition temperature of less than 0 ° C. and a monomer having a polyoxyalkylene skeleton having a weight average molecular weight of 1,000 or more and less than 30,000. As a (meth) acrylic monomer having a (meth) acrylic polymer (B) containing 0.05 part by mass to 50 parts by mass and represented by the following general formula (1), the glass transition temperature of the homopolymer is 0 ° C. or higher. Containing (meth) acrylic polymer (C) 0.01 part by mass to 40 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 alkyl group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group]
However, the (meth) acrylic polymer (C) does not contain a polyoxyalkylene skeleton.

  Hereinafter, the polymer (A), the (meth) acrylic polymer (B), and the (meth) acrylic polymer (C) 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 the (meth) acrylic polymer (C) and has high transparency is suitable.

  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 and the adhesive strength with time may be inferior.

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

_{1 / Tg = W 1 / Tg} 1 + W 2 / Tg 2 + ··· + Wn / Tg n (X)
[In the formula (X), 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 (X) 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, numerical values are listed in “Polymer Handbook” (3rd edition, John Wiley & Sons, Inc, 1989). 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 introduction tube, and a reflux condenser, 100 parts by mass of monomer X, 0.2 parts by mass 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 was weighed in an aluminum open cell, and a nitrogen atmosphere of 50 ml / min was used using a temperature modulation DSC (trade name “Q-2000”, manufactured by T.A. Instruments Inc.). Under the temperature rising 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 from the straight line extending the high temperature side base line, 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.

  Moreover, the weight average molecular weight (Mw) of a polymer (A) is about 30,000-5 million, for example. If the weight average molecular weight (Mw) is less than 30,000, the cohesive force of the pressure-sensitive adhesive may be insufficient, resulting in poor adhesion reliability. On the other hand, when the weight average molecular weight (Mw) exceeds 5,000,000, the fluidity of the pressure-sensitive adhesive is lowered, and there are cases where the adhesive strength increases with time.

[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 can be configured such that the (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.

  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 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 esters such as octadecyl acrylate, isooctadecyl (meth) 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;
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl Hydroxyl group-containing monomers such as hydroxyalkyl (meth) acrylates such as 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;
Phosphate 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-ethylhexylitaconimide, 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.

一般式（Ｍ１）式中、Ｒ^１は、２価の有機基である。
Ｎ−ビニル環状アミドの具体例としては、Ｎ−ビニル−２−ピロリドン、Ｎ−ビニル−２−ピペリドン、Ｎ−ビニル−３−モルホリノン、Ｎ−ビニル−２−カプロラクタム、Ｎ−ビニル−１，３−オキサジン−２−オン、Ｎ−ビニル−３，５−モルホリンジオン等が挙げられる。特に好ましくはＮ−ビニル−２−ピロリドン、Ｎ−ビニル−２−カプロラクタムである。Ｎ−ビニル環状アミドからなる群より選ばれるモノマーの使用量は特に制限はされないが、通常、前記アクリル系ポリマーを調製するためのモノマー成分全量に対して、共重合性モノマーを０．０１質量％〜４０質量％、好ましくは０．１質量％〜３０質量％、さらに好ましくは０．５質量％〜２０質量％含有することができる。 In the pressure-sensitive adhesive composition of the above aspect, the acrylic polymer has at least one monomer selected from the group consisting of an N-vinyl cyclic amide represented by the following general formula (M1) and a hydroxyl group-containing monomer as a monomer unit. It is preferable to contain. In particular, it is preferable to use a monomer selected from the group consisting of N-vinyl cyclic amides.

In the general formula (M1), R ¹ is a divalent organic group.
Specific examples of the N-vinyl cyclic amide include N-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3. -Oxazin-2-one, N-vinyl-3,5-morpholinedione and the like. Particularly preferred are N-vinyl-2-pyrrolidone and N-vinyl-2-caprolactam. The amount of the monomer selected from the group consisting of N-vinyl cyclic amides is not particularly limited, but is usually 0.01% by mass of the copolymerizable monomer based on the total amount of monomer components for preparing the acrylic polymer. -40% by mass, preferably 0.1% by mass to 30% by mass, more preferably 0.5% by mass to 20% by mass.

  As specific examples of the hydroxyl group-containing monomer, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and the like can be preferably used. The amount of the hydroxy group-containing monomer used is not particularly limited, but is usually 40% by mass or less, preferably 20% by mass or less, and more preferably 20% by mass or less, based on the total amount of monomer components for preparing the acrylic polymer. Preferably it can contain 10 mass%.

  By containing 0.01% by mass or more of the copolymerizable monomer, it is possible to prevent a decrease in the cohesive force of the pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed of an acrylic pressure-sensitive adhesive composition. 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 this embodiment, when used for an adherend made of metal or an adherend on which a metal film is formed (for example, a touch panel on which an electrically conductive film (ITO) is formed), an acrylic material is used. It is desirable that the polymer has no carboxyl group. Moreover, from a corrosive viewpoint, it is desirable not to contain substantially acidic functional groups other than a carboxyl group. Therefore, the monomer constituent unit constituting the acrylic polymer of the present embodiment may be substantially free of a monomer having a carboxyl group or an acidic functional group other than the carboxyl group.

  The acidic functional group refers to a functional group having active hydrogen. Examples of the acidic functional group include a carboxyl group, a sulfonic acid group, and a phosphoric acid group. “Substantially free” of an acidic functional group means that it is not actively incorporated unless it is inevitably incorporated. Specifically, the proportion (% by mass) of the monomer having an acidic functional group in the total amount of the constituent units constituting the acrylic polymer is less than 1% by mass, preferably less than 0.5% by mass. means.

  Moreover, in order to adjust the cohesion force of the adhesive composition to form in an acrylic polymer, you may contain a polyfunctional monomer as needed.

  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, poly Ester acrylate, urethane acrylate, butyl diol (meth) acrylate, hexyl diol (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, the number of functional groups, and the like, 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 initial pressure-sensitive adhesive strength The suppression effect may be reduced. On the other hand, if it is less than 0.01% by mass, for example, the cohesive strength of the pressure-sensitive adhesive composition may be reduced, and the increase in the adhesive strength over time may be insufficient.

  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, photopolymerization can be suitably used from the advantage of improving the adhesive property. 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-based polymerization initiators (for example, dibenzoyl peroxide, t-butylpermaleate, lauroyl peroxide) ); Redox polymerization initiators, and the like.

  Although it does not restrict | limit especially as the usage-amount of a thermal-polymerization initiator, For example, 0.01 mass part-5 mass parts with respect to 100 mass parts of monomer components which prepare an acryl-type polymer, Preferably 0.05 mass part-3 It mix | blends in the quantity in the range of the mass part.

  Although it does not restrict | limit especially as a photoinitiator, For example, a benzoin ether type photoinitiator, an acetophenone type photoinitiator, an alpha-ketol type photoinitiator, an aromatic sulfonyl chloride type photoinitiator, photoactivity 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 Corp.], 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 Corporation], 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-based photopolymerization initiator include 2-naphthalene sulfonyl 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-based 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 Oxide, bis (2- Toxibenzoyl) (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, bis 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 (2 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-trimethyl Benzoyl-n-butylphosphine oxide, bis (2,4,4 -Trimethylbenzoyl) phenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,4-dibutoxyphenylphosphine oxide, 1,10-bis [bis (2,4,6-trimethylbenzoyl) phosphine oxide] Examples include decane and tri (2-methylbenzoyl) phosphine oxide.

  Although the usage-amount of a photoinitiator is not restrict | limited in particular, For example, 0.01 mass part-5 mass parts with respect to 100 mass parts of monomer components which prepare an acrylic polymer, Preferably it is 0.05 mass part-3 masses. In an amount within the range of parts.

  Here, when the usage-amount of a photoinitiator is less than 0.01 mass part, a polymerization reaction may become inadequate. 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 thereby, the cohesive force of the adhesive layer formed becomes low, and the adhesive force raise with time may become inadequate. In addition, a photopolymerization initiator can be used individually or in combination of 2 or more types.

  In the present embodiment, the polymer (A) is a partial polymer (acrylic polymer syrup) obtained by irradiating a mixture of the monomer component and the polymerization initiator with ultraviolet rays (UV) to partially polymerize the monomer component. It can also be prepared as. A pressure-sensitive adhesive composition is prepared by blending the acrylic polymer syrup with a (meth) acrylic polymer (B) and a (meth) acrylic polymer (C), which will be described later. It can also be applied to the coated body and irradiated with ultraviolet rays to complete the polymerization. That is, the acrylic polymer syrup is a precursor of the polymer (A), and the acrylic polymer syrup is blended with the (meth) acrylic polymer (B) and the (meth) acrylic polymer (C). It corresponds to the pressure-sensitive adhesive composition of the embodiment.

[(Meth) acrylic polymer (B)]
The (meth) acrylic polymer (B) is a (meth) acrylic polymer having a weight average molecular weight of 1000 or more and less than 30000 and containing a monomer having a polyoxyalkylene skeleton as a monomer unit. Functions as an additive for adjusting the adhesive strength.

［（２）式中、Ｒ_１は水素またはメチル基であり、Ｒ_２は水素または１価の有機基であり、ｍおよびｐは２〜４の整数、ｎおよびｑは０または２〜４０の整数であり、ｎおよびｑが同時に０となることはない] Monomers having a polyoxyalkylene skeleton constituting the (meth) acrylic polymer (B) are (meth) acrylic acid oxyalkylene adducts and reactive substituents such as acryloyl, methacryloyl and allyl groups in the molecule. And anionic reactive surfactants, nonionic reactive surfactants, cationic reactive surfactants, and the like. The polyoxyalkylene chain expresses an appropriate balance between incompatibility and incompatibility between the polymer (A) and the (meth) acrylic polymer (B). The increase in adhesive strength can be adjusted moderately. In particular, an oxyalkylene group-containing monomer represented by the following general formula (2) can be suitably used.

[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, methoxy polyethylene glycol (meth) acrylate, ethoxy polyethylene glycol (meth) acrylate, butoxy polyethylene glycol (meth) acrylate, octoxy polyethylene glycol (meth) acrylate, and lauroxy polyethylene glycol. (Meth) acrylate, stearoxy polyethylene glycol (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, phenoxy polyethylene glycol-polypropylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, nonylphenoxy polypropylene glycol (meth) acrylate, Nonylphenoxy polyethylene glycol Meth) acrylate, nonylphenoxy ethylene glycol - polypropylene glycol (meth) acrylate, octoxypolyethylene glycol - polypropylene glycol (meth) acrylate. These oxyalkylene group-containing monomers can be used alone or in combination of two or more.

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

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

  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 formulas (A1) to (A10).

［式（Ａ１）中のＲ_１は水素またはメチル基を表し、Ｒ_２は炭素数１から３０の炭化水素基またはアシル基を表し、Ｘはアニオン性親水基を表し、Ｒ_３およびＲ_４は同一または異なって、炭素数１から６のアルキレン基を表し、平均付加モル数ｍおよびｎは０〜４０、ただし（ｍ＋ｎ）は３〜４０の数を表す。］

[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 The alkylene groups having 1 to 6 carbon atoms are the same or different, and the average added mole number m and n are 0 to 40, where (m + n) represents 3 to 40. ]

［式（Ａ２）中のＲ_１は水素またはメチル基を表し、Ｒ_２およびＲ_７は同一または異なって、炭素数１から６のアルキレン基を表し、Ｒ_３およびＲ_５は同一または異なって、水素またはアルキル基を表し、Ｒ_４およびＲ_６は同一または異なって、水素、アルキル基、ベンジル基またはスチレン基を表し、Ｘはアニオン性親水基を表し、平均付加モル数ｍおよびｎは０〜４０、ただし（ｍ＋ｎ）は３〜４０の数を表す。］

[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 the average number of added moles m and n are 0 to 40, where (m + n) represents a number from 3 to 40. ]

［式（Ａ３）中のＲ_１は水素またはメチル基を表し、Ｒ_２は炭素数１から６のアルキレン基を表し、Ｘはアニオン性親水基を表し、平均付加モル数ｎは３〜４０の数を表す。］

[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. ]

［式（Ａ４）中のＲ_１は水素またはメチル基を表し、Ｒ_２は炭素数１から３０の炭化水素基またはアシル基を表し、Ｒ_３およびＲ_４は同一または異なって、炭素数１から６のアルキレン基を表し、Ｘはアニオン性親水基を表し、平均付加モル数ｍおよびｎは０〜４０、ただし（ｍ＋ｎ）は３〜４０の数を表す。］

[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. ]

［式（Ａ５）中のＲ_１は炭化水素基、アミノ基、カルボン酸残基を表し、Ｒ_２は炭素数１から６のアルキレン基を表し、Ｘはアニオン性親水基を表し、平均付加モル数ｎは３〜４０の整数を表す。］

[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. ]

［式（Ａ６）中のＲ_１は炭素数１から３０の炭化水素基、Ｒ_２は水素または炭素数１から３０の炭化水素基を表し、Ｒ_３は水素またはプロペニル基を表し、Ｒ_４は炭素数１から６のアルキレン基を表し、Ｘはアニオン性親水基を表し、平均付加モル数ｎは３〜４０の数を表す。］

[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 An alkylene group having 1 to 6 carbon atoms is represented, X represents an anionic hydrophilic group, and the average added mole number n represents a number of 3 to 40. ]

［式（Ａ７）中のＲ_１は水素またはメチル基を表し、Ｒ_２およびＲ_４は同一または異なって、炭素数１から６のアルキレン基を表し、Ｒ_３は炭素数１から３０の炭化水素基を表し、Ｍは水素、アルカリ金属、アンモニウム基、またはアルカノールアンモニウム基を表し、平均付加モル数ｍおよびｎは０〜４０、ただし（ｍ＋ｎ）は３〜４０の数を表す。］

[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. Represents a group, 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. ]

［式（Ａ８）中のＲ_１およびＲ_５は同一または異なって、水素またはメチル基を表し、Ｒ_２およびＲ_４は同一または異なって、炭素数１から６のアルキレン基を表し、Ｒ_３は炭素数１から３０の炭化水素基を表し、Ｍは水素、アルカリ金属、アンモニウム基、またはアルカノールアンモニウム基を表し、平均付加モル数ｍおよびｎは０〜４０、ただし（ｍ＋ｎ）は３〜４０の数を表す。］

[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. ]

［式（Ａ９）中のＲ_１は炭素数１から６のアルキレン基を表し、Ｒ_２は炭素数１から３０の炭化水素基を表し、Ｍは水素、アルカリ金属、アンモニウム基、またはアルカノールアンモニウム基を表し、平均付加モル数ｎは３〜４０の数を表す。］

[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. ]

［式（Ａ１０）中のＲ_１、Ｒ_２、およびＲ_３は同一または異なって、水素またはメチル基を表し、Ｒ_４は炭素数０から３０の炭化水素基（炭素数０の場合はＲ_４がないことを示す）を表し、Ｒ_５およびＲ_６は同一または異なって、炭素数１から６のアルキレン基を表し、Ｘはアニオン性親水基を表し、平均付加モル数ｍおよびｎは０〜４０、ただし（ｍ＋ｎ）は３〜４０の数を表す。］

[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. ]

［式（ａ１）中のＭ_１は水素、アルカリ金属、アンモニウム基、またはアルカノールアンモニウム基を表す。］ 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).

[M ₁ in Formula (a1) represents hydrogen, an alkali metal, an ammonium group, or an alkanol ammonium group. ]

［式（ａ２）中のＭ２およびＭ３は同一または異なって、水素、アルカリ金属、アンモニウム基、またはアルカノールアンモニウム基を表す。］

[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).

［式（Ｎ１）中のＲ_１は水素またはメチル基を表し、Ｒ_２は炭素数１から３０の炭化水素基またはアシル基を表し、Ｒ_３およびＲ_４は同一または異なって、炭素数１から６のアルキレン基を表し、平均付加モル数ｍおよびｎは０〜４０、ただし（ｍ＋ｎ）は３〜４０の数を表す。］

[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. ]

［式（Ｎ２）中のＲ_１は水素またはメチル基を表し、Ｒ_２、Ｒ_３およびＲ_４は同一または異なって、炭素数１から６のアルキレン基を表し、平均付加モル数ｎ、ｍ、およびｌは０〜４０であって、（ｎ＋ｍ＋ｌ）が３〜４０となる数を表す。］

[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 0 to 40, and (n + m + 1) represents a number from 3 to 40. ]

［式（Ｎ３）中のＲ_１は水素またはメチル基を表し、Ｒ_２およびＲ_３は同一または異なって、炭素数１から６のアルキレン基を表し、Ｒ_４は炭素数１から３０の炭化水素基またはアシル基を表し、平均付加モル数ｍおよびｎは０〜４０、ただし（ｍ＋ｎ）は３〜４０の数を表す。］

[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, the average number of added moles m and n is 0 to 40, where (m + n) represents a number of 3 to 40. ]

［式（Ｎ４）中のＲ_１およびＲ_２は同一または異なって、炭素数１から３０の炭化水素基を表し、Ｒ_３は水素またはプロペニル基を表し、Ｒ_４は炭素数１から６のアルキレン基を表し、平均付加モル数ｎは３〜４０の数を表す。］

[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 Represents the group, and the average addition mole number n represents a number of 3 to 40. ]

［式（Ｎ５）中のＲ_１およびＲ_３は同一または異なって、炭素数１から６のアルキレン基を表し、Ｒ_２およびＲ_４は同一または異なって、水素、炭素数１から３０の炭化水素基、またはアシル基を表し、平均付加モル数ｍおよびｎは０〜４０、ただし（ｍ＋ｎ）は３〜４０の数を表す。］

[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; 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. ]

［式（Ｎ６）中のＲ_１、Ｒ_２、およびＲ_３は同一または異なって、水素またはメチル基を表し、Ｒ_４は炭素数０から３０の炭化水素基（炭素数０の場合はＲ_４がないことを示す）を表し、Ｒ_５およびＲ_６は同一または異なって、炭素数１から６のアルキレン基を表し、平均付加モル数ｍおよびｎは０〜４０、ただし（ｍ＋ｎ）は３〜４０の数を表す。］

[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 3. The number of 40 is represented. ]

  The (meth) acrylic polymer (B) may be a polymer composed only of a monomer having a polyoxyalkylene skeleton, but in addition to a monomer having a polyoxyalkylene skeleton, a (meth) acrylic acid ester monomer is used. It may be a copolymer.

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, (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 (meth) acrylic acid-2-hydroxyethyl, (meth) acrylic acid-2-hydroxypropyl, adducts of lactones and (meth) acrylic acid-2-hydroxyethyl;
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-ethylhexylitaconimide, 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-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.

  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, more preferably 2000 or more and less than 10,000, and particularly preferably 2500 or more and less than 6000. When the weight average molecular weight is 30000 or more, the compatibility with the polymer (A) is lowered, and the initial adhesive strength may not be sufficiently lowered. Further, if the weight average molecular weight is less than 1000, the molecular weight becomes low, and thus there is a case where an increase in adhesive strength over time cannot be obtained.

[(Meth) acrylic polymer (C)]
The (meth) acrylic polymer (C) has a weight average molecular weight of 1000 or more and less than 30000, is represented by the following general formula (1), and has a glass transition temperature of a homopolymer of 0 ° C. or more. In the pressure-sensitive adhesive composition, it functions as an additive for adjusting the adhesive strength.
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 alkyl group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group]

  Examples of the (meth) acrylic monomer represented by the general formula (1) having a glass transition temperature of 0 ° C. or higher include dicyclopentanyl methacrylate (Tg: 175 ° C.), dicyclopentanyl acrylate ( Tg: 120 ° C., isobornyl methacrylate (Tg: 173 ° C.), isobornyl acrylate (Tg: 97 ° C.), cyclohexyl methacrylate (Tg: 66 ° C.), cyclohexyl acrylate (Tg: 15 ° C.), isobutyl methacrylate (Tg) : 48 ° C), methyl methacrylate (Tg: 105 ° C), 1-adamantyl methacrylate (Tg: 250 ° C), 1-adamantyl acrylate (Tg: 153 ° C), and the like.

The (meth) acrylic polymer may be a copolymer of the above (meth) acrylic monomer and the following monomer (however, the glass transition temperature of the homopolymer is 0 ° C. or higher). Examples of the monomer copolymerizable with the (meth) acrylic monomer include acryloylmorpholine (Tg: 145 ° C.), dimethyl acrylamide (Tg: 119 ° C.), diethyl acrylamide (Tg: 81 ° C.), dimethylaminopropyl acrylamide (Tg: Amide group-containing vinyl monomers such as isopropyl acrylamide (Tg: 134 ° C.), hydroxyethyl acrylamide (Tg: 98 ° C.);
Nitrogen-containing heterocyclic monomers such as N-vinyl-pyrrolidone (Tg: 54 ° C.);
Lactam monomers such as N-vinylcaprolactam such as N-vinyl-2-caprolactam (Tg: 176 ° C.);
Examples thereof include a hydroxyl group-containing monomer such as hydroxyalkyl (meth) acrylate such as hydroxyethyl methacrylate (Tg: 40 ° C.).

  By including a (meth) acrylic monomer having a homopolymer glass transition temperature of 0 ° C. or higher in the (meth) acrylic polymer (C), it is possible to increase the adhesive strength over time.

In the present embodiment, R ² in the general formula (1) is preferably an alicyclic hydrocarbon group such as a cyclohexyl group, an isobornyl group, or 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. By giving the (meth) acrylic polymer (C) as a monomer unit to the (meth) acrylic monomer having a relatively bulky structure in this way, the adhesive strength over time and the rate of increase in the adhesive strength can be increased. Can do.

  Furthermore, the alicyclic hydrocarbon group of the (meth) acrylic monomer having an alicyclic structure constituting the (meth) acrylic polymer (C) 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 (C) 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. Moreover, the adhesive force with the passage of time of the adhesive composition (adhesive sheet) and the rate of increase in adhesive strength can be increased.

また、このような橋かけ環構造を有する三環以上の脂環式構造を持つ（メタ）アクリル系モノマーの例としては、ジシクロペンタニルメタクリレート、ジシクロペンタニルアクリレート、ジシクロペンタニルオキシエチルメタクリレート、ジシクロペンタニルオキシエチルアクリレート、トリシクロペンタニルメタクリレート、トリシクロペンタニルアクリレート、１−アダマンチルメタクリレート、１−アダマンチルアクリレート、２−メチル−２−アダマンチルメタクリレート、２−メチル−２−アダマンチルアクリレート、２−エチル−２−アダマンチルメタクリレート、２−エチル−２−アダマンチルアクリレート等の（メタ）アクリル酸エステルを挙げることができる。この（メタ）アクリル系モノマーは、単独であるいは２種以上を組み合わせて使用することができる。 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 (C) or 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 (C).

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, (Meth) acrylic acid esters such as 2-ethyl-2-adamantyl methacrylate and 2-ethyl-2-adamantyl acrylate can be mentioned. These (meth) acrylic monomers can be used alone or in combination of two or more.

  Examples of the (meth) acrylic polymer (C) include a copolymer of dicyclopentanyl methacrylate (DCPMA) and methyl methacrylate (MMA), and isobornyl methacrylate (IBXMA) and methyl methacrylate (MMA). Examples thereof include a copolymer, a copolymer of cyclohexyl methacrylate (CHMA) and methyl methacrylate (MMA), and a copolymer of cyclohexyl methacrylate (CHMA) and isobutyl methacrylate (IBMA).

  The (meth) acrylic polymer (C) may contain a monomer other than the (meth) acrylic monomer having a homopolymer glass transition temperature of 0 ° C. or higher, but the monomer having a polyoxyalkylene skeleton is a constituent component. It is preferable not to. If the (meth) acrylic polymer (C) is composed of a monomer having a polyoxyalkylene skeleton, an increase in adhesive strength over time may not be obtained.

The weight average molecular weight of the (meth) acrylic polymer (C) 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 compatibility with the polymer is lowered, and the initial decrease in adhesive strength may be inhibited. Further, if the weight average molecular weight is less than 1000, the molecular weight becomes low, and the effect of increasing the adhesive strength over time may not be obtained.

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

  The (meth) acrylic polymer (C) has a glass transition temperature (Tg) of 30 ° C to 300 ° C, preferably 50 ° C to 280 ° C, more preferably 90 ° C to 280 ° C, still more preferably 110 ° C to 250 ° C. It is desirable that If the glass transition temperature (Tg) is less than 30 ° C., the increase in adhesive strength over time may be small. The glass transition temperature of the (meth) acrylic polymer (C) is a nominal value described in literatures, catalogs, or the like, or a value calculated based on the above Fox equation.

  (Meth) acrylic polymer (B) and (meth) acrylic polymer (C) are, for example, solution polymerization method, bulk polymerization method, emulsion polymerization method, (meth) acrylic monomer having the above-described structure, It can be produced by polymerization by suspension polymerization, bulk polymerization or the like.

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

  Although it does not restrict | limit especially as the usage-amount of a chain transfer agent, Usually, 0.1 mass part-20 mass parts with respect to 100 mass parts of (meth) acrylic-type monomers, Preferably, 0.2 mass Part-15 mass parts, More preferably, it contains 0.3 mass part-10 mass parts. Thus, the (meth) acrylic-type polymer (B) and (meth) acrylic-type polymer (C) 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 polymer (A), (meth) acrylic polymer (B), and (meth) acrylic polymer (C) described above as essential components. The content of the (meth) acrylic polymer (B) is 0.05 to 50 parts by mass, preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the polymer (A). More preferably, it is 0.5 mass part-15 mass parts, More preferably, it is 1 mass part-10 mass parts. The content of the (meth) acrylic polymer (C) is 0.01 to 40 parts by mass, preferably 0.03 to 20 parts by mass with respect to 100 parts by mass of the polymer (A). More preferably, it is 0.05-10 mass parts, More preferably, it is 0.08-5 mass parts. In the pressure-sensitive adhesive composition of the present embodiment, by introducing a polyoxyalkylene skeleton into the (meth) acrylic polymer (B), the (meth) acrylic polymer (B) is interfaced immediately after bonding. The (meth) acrylic polymer (C) works to increase the adhesion at the interface and contributes to an increase in adhesive strength over time. It is thought that. In addition, when a (meth) acrylic-type polymer (B) is added exceeding 50 mass parts, the transparency of the adhesive layer formed with the adhesive composition which concerns on this Embodiment will fall. Moreover, when the addition amount of (meth) acrylic-type polymer (B) is less than 0.05 mass part, the adhesive force suppression effect at the time of adherend bonding is weak, and the malfunction which cannot rework may arise. If the (meth) acrylic polymer (C) is added in excess of 40 parts by mass, the initial adhesive force suppressing effect by the (meth) acrylic polymer (B) may be inhibited. Moreover, when the addition amount of (meth) acrylic-type polymer (C) is less than 0.01 mass part, the adhesive force raise effect with time may be inadequate.

  In addition to the polymer (A), the (meth) acrylic polymer (B), and the (meth) acrylic polymer (C) described above, the pressure-sensitive adhesive composition has various additions that are common in the field of pressure-sensitive adhesive compositions. An agent may be contained as an optional component. 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 or the like 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, trimethylolpropane tri Mention 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 and more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the polymer (A). preferable. When content is less than 0.01 mass part, the cohesion force of an adhesive composition may become small and it may be inferior to adhesive reliability. 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, and the increase in pressure-sensitive adhesive strength with time may be inferior.

  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). .

[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. 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 55.0 mass% to 99.0 mass%, preferably 60.0 mass% to 95.0 mass%. If the solvent-insoluble component ratio is less than 55.0% by mass, the cohesive force may be insufficient, resulting in poor adhesion reliability. If the solvent-insoluble component ratio exceeds 99.0% by mass, the cohesive force becomes too high. In some cases, the increase in adhesive strength over time may be insufficient. In addition, the evaluation method of a solvent insoluble component rate is mentioned later.

  Although the thickness of an adhesive layer is not specifically limited, Usually, favorable adhesiveness can be implement | achieved by setting it as 3 micrometers-200 micrometers, for example, Preferably it is 5 micrometers-150 micrometers. If the thickness of the pressure-sensitive adhesive layer is less than 3 μm, the increase in adhesive strength over time may be inferior. On the other hand, if the thickness of the pressure-sensitive adhesive layer exceeds 200 μm, the effect of suppressing the pressure-sensitive adhesive force immediately after bonding may be insufficient. is there.

  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.

  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 according to 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.

  In the pressure-sensitive adhesive sheet of this embodiment, a release liner can be bonded to the surface of the pressure-sensitive adhesive layer for the purpose of protecting the pressure-sensitive adhesive surface as necessary.

  The material constituting the release liner includes paper and plastic film, but a plastic film is preferably used from the viewpoint of 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.

  Immediately after being bonded to the adherend, the pressure-sensitive adhesive sheet has a characteristic that adhesive force is small and reworking is possible, the adhesive force increases with time, and adhesion reliability is high. Immediately after the pressure-sensitive adhesive sheet is bonded (after 30 minutes at room temperature), it can be evaluated by a 180 ° peel adhesion test when peeled at a tensile speed of 300 mm / min and a peel angle of 180 °, particularly 1.4 N / 25 mm. If it is below, it is judged as good. 180 degree peeling adhesive force becomes like this. Preferably it is 1.0 N / 25mm or less, More preferably, it is 0.8 N / 25mm or less. The 180 ° peel adhesion test is measured according to the method and conditions described in the examples described later.

  The adhesive strength of the adhesive sheet after the elapse of time can be evaluated by a 180 ° peeling adhesive strength test when it is peeled off at a pulling rate of 300 mm / min and a peeling angle of 180 °, particularly 5.0 N / 25 mm or more. Is considered good. 180 degree peeling adhesive force becomes like this. Preferably it is 6.0 N / 25mm or more, More preferably, it is 7.0 N / 25mm or more. The 180 ° peel adhesion test is measured according to the method and conditions described in the examples described later.

  Furthermore, the pressure-sensitive 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.

[Optical film with adhesive layer]
Furthermore, this invention provides the optical film with an adhesive layer formed by forming the said adhesive on the at least single side | surface of an optical film. As an optical film that can be used in the present invention, a polarizing plate, a wavelength plate, an optical compensation film, a light diffusion sheet, a reflection sheet, an antireflection sheet, used in an image display device such as a liquid crystal display, a plasma display, and an organic EL display, A brightness enhancement film, a transparent conductive film (ITO film), etc. can be mentioned.

  The method for forming the pressure-sensitive adhesive layer on at least one surface of the optical film is not particularly limited, and the pressure-sensitive adhesive layer may be formed by directly applying the pressure-sensitive adhesive composition of the present embodiment to the surface of the optical film. A pressure-sensitive adhesive layer may be formed on a release liner, and the pressure-sensitive adhesive layer surface may be bonded to the optical film to transfer the pressure-sensitive adhesive layer to the optical film. The thickness of the pressure-sensitive adhesive layer in the optical film with the pressure-sensitive adhesive layer is preferably 3 μm to 200 μm, more preferably 5 μm to 150 μm, and still more preferably 10 to 100 μm.

  The adhesive sheet of the present embodiment is low in adhesive strength to the extent that it can be reworked at the initial stage of attachment, and then adheres firmly to the adherend, and further has a pressure-sensitive adhesive layer that is also excellent in transparency. In addition to the optical applications described above, it can be suitably used as a bonding material for members in mobile devices and other electric and electronic devices, or as a bonding material for various members in automobiles, home appliances, and the like.

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

(Preparation of acrylic polymer syrup 1 (2EHA / NVP = 86/14) as component (A))
86 parts by mass of 2-ethylhexyl acrylate (2EHA), 14 parts by mass of N-vinyl-2-pyrrolidone (NVP), 0.05 parts by mass of a photopolymerization initiator (trade name: Irgacure 184, manufactured by BASF), and photopolymerization start 0.05 parts by mass of an agent (trade name: Irgacure 651, manufactured by BASF) was charged into a four-necked flask. The mixture was exposed to ultraviolet light under a nitrogen atmosphere and partially photopolymerized to obtain a partially polymerized product (acrylic polymer syrup) having a polymerization rate of about 8% by mass.

(Preparation of acrylic polymer syrup 2 (2EHA / NVP / HEA = 78/18/4) as component (A))
78 parts by mass of 2-ethylhexyl acrylate (2EHA), 18 parts by mass of N-vinyl-2-pyrrolidone (NVP), 4 parts by mass of 2-hydroxyethyl acrylate (HEA), photopolymerization initiator (trade name: Irgacure 184, BASF 0.05 parts by mass) and 0.05 parts by mass of a photopolymerization initiator (trade name: Irgacure 651, manufactured by BASF) were charged into a four-necked flask. The mixture was exposed to ultraviolet light under a nitrogen atmosphere and partially photopolymerized to obtain a partially polymerized product (acrylic polymer syrup 2) having a polymerization rate of about 9% by mass.

(Preparation of (meth) acrylic polymer 1 (PME-400 = 100) as component (B))
100 parts by mass of ethyl acetate, 100 parts by mass of methoxypolyethylene glycol methacrylate (trade name: Blenmer PME-400, manufactured by NOF Corporation) having an average addition mole number of oxyethylene units of 9 and methyl thioglycolate as a chain transfer agent 3 parts by mass 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 resulting (meth) acrylic polymer 1 had a weight average molecular weight of 4300.

(Preparation of (meth) acrylic polymer 2 (CD552 = 100) as component (B))
100 parts by mass of ethyl acetate, 100 parts by mass of methoxypolyethylene glycol methacrylate (trade name: CD552, manufactured by Sartomer) having an average addition mole number of oxyethylene units of 12 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 4,100.

(Preparation of (meth) acrylic polymer 3 (PME-400 / DCPMA = 80/20) as component (B))
100 parts by mass of ethyl acetate, 80 parts by mass of methoxypolyethylene glycol methacrylate (trade name: Blenmer PME-400, manufactured by NOF Corporation) having an average addition mole number of oxyethylene units of 9, dicyclopentanyl methacrylate (DCPMA) ( Product name: FA-513M, manufactured by Hitachi Chemical Co., Ltd.) 20 parts by mass, and 3 parts by mass of methyl thioglycolate as a chain transfer agent were equipped with a stirring blade, thermometer, nitrogen gas inlet tube, cooler, and dropping funnel. A four-necked flask 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 weight average molecular weight of the obtained (meth) acrylic polymer 3 was 4700.

(Preparation of (meth) acrylic polymer 1 (DCPMA / MMA = 80/20) as component (C))
100 parts by mass of toluene, 80 parts by mass of dicyclopentanyl methacrylate (DCPMA) (trade name: FA-513M, manufactured by Hitachi Chemical Co., Ltd.), 20 parts by mass of methyl methacrylate (MMA) and 3 parts by mass of thioglycolic acid as a chain transfer agent The part was put into a four-necked flask equipped with a stirring blade, 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 1 had a weight average molecular weight of 3300.

(Preparation of (meth) acrylic polymer 2 (DCPMA / MMA = 60/40) as component (C))
100 parts by mass of toluene, 60 parts by mass of dicyclopentanyl methacrylate (DCPMA) (trade name: FA-513M, manufactured by Hitachi Chemical Co., Ltd.), 40 parts by mass of methyl methacrylate (MMA) and 3 parts by mass of thioglycolic acid as a chain transfer agent The part was put into a four-necked flask equipped with a stirring blade, 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 4600.

(Preparation of (meth) acrylic polymer 3 (DCPMA = 100) as component (C))
100 parts by mass of toluene, 100 parts by mass of dicyclopentanyl methacrylate (DCPMA) (trade name: FA-513M, manufactured by Hitachi Chemical Co., Ltd.) and 3 parts by mass of thioglycolic acid as a chain transfer agent, stirring blade, thermometer, nitrogen The solution was put into a four-necked flask equipped with a 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 3 had a weight average molecular weight of 4600.

(Preparation of (meth) acrylic polymer 4 (IBXMA / MMA = 60/40) as component (C))
100 parts by mass of ethyl acetate, 60 parts by mass of isobornyl methacrylate (IBXMA) (trade name: FA-513M, manufactured by Co., Ltd.), 40 parts by mass of methyl methacrylate (MMA) and 3 parts by mass of thioglycerol as a chain transfer agent , And put into a four-necked flask equipped with a thermometer, nitrogen gas inlet tube, cooler, and 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 4 had a weight average molecular weight of 5,600.

(Preparation of (meth) acrylic polymer 5 (CHMA / MMA = 60/40) as component (C))
100 parts by mass of ethyl acetate, 60 parts by mass of cyclohexyl methacrylate (CHMA) (trade name: FA-513M, manufactured by Co., Ltd.), 40 parts by mass of methyl methacrylate (MMA) and 3 parts by mass of thioglycerol as a chain transfer agent, stirring blade, temperature A four-necked flask equipped with a total, a nitrogen gas inlet tube, a cooler, 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 5 had a weight average molecular weight of 4,100.

(Preparation of (meth) acrylic polymer 6 (CHMA / IBMA = 60/40) as component (C))
After blending 100 parts by mass of toluene, 60 parts by mass of cyclohexyl methacrylate (CHMA), 40 parts by mass of isobutyl methacrylate (IBMA) and 4 parts by mass of thioglycolic acid as a chain transfer agent, nitrogen gas was blown to remove dissolved oxygen. Next, when the temperature was raised to 90 ° C., perhexyl O (manufactured by NOF Corporation, 0.005 parts by mass) and perhexyl D (manufactured by NOF Corporation, 0.01 parts by mass) were mixed. Furthermore, after stirring at 90 ° C. for 1 hour, the temperature was raised to 150 ° C. over 1 hour and stirred at 150 ° C. for 1 hour. Subsequently, it heated up to 170 degreeC over 1 hour, and stirred for 60 minutes at 170 degreeC. The weight average molecular weight of the obtained (meth) acrylic polymer 6 was 4000.

(Preparation of (meth) acrylic polymer 7 (CHMA / AA = 95/5) as component (C))
100 parts by mass of toluene, 95 parts by mass of cyclohexyl methacrylate (CHMA), 5 parts by mass of acrylic acid (AA) and 3 parts by mass of thioglycolic acid as a chain transfer agent, stirring blade, thermometer, nitrogen gas introduction tube, cooler, dropping funnel Into a four-necked flask equipped with 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 7 was 3600.

(Preparation of (meth) acrylic polymer 8 (MMA = 100) as component (C))
100 parts by mass of toluene, 100 parts by mass of methyl methacrylate (MMA) and 3 parts by mass of thioglycolic acid as a chain transfer agent are charged into a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, cooler, and dropping funnel. did. 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 7,300.

(Preparation of (meth) acrylic polymer 9 (BA = 100) as component (C))
Four-necked flask equipped with 100 parts by mass of ethyl acetate, 100 parts by mass of methyl methacrylate (BA) and 3 parts by mass of methyl thioglycolate as a chain transfer agent, equipped with a stirring blade, thermometer, nitrogen gas introduction tube, cooler, and dropping funnel It was thrown into. 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 9 was 5900.

Example 1
(Preparation of acrylic pressure-sensitive adhesive composition)
100 parts by mass of the acrylic polymer syrup described above, 4 parts by mass of the (meth) acrylic polymer (B) 1 described above, 0.1 part by mass of the (meth) acrylic polymer (C) 1 and a crosslinking agent After adding 0.1 part by mass of trimethylolpropane triacrylate (TMPTA), these were uniformly mixed to prepare an acrylic pressure-sensitive adhesive composition.

(Production of acrylic adhesive layer)
The acrylic adhesive composition described above is applied to the release-treated surface of a 38 μm-thick polyester film (trade name: Diafoil MRF, manufactured by Mitsubishi Plastics Co., Ltd.) having one surface peeled with silicone so that the final thickness is 50 μm. Was applied to form a coating layer. Next, a 38 μm thick polyester film (trade name: Diafoil MRE, manufactured by Mitsubishi Resin Co., Ltd.) having one surface peeled off with silicone on the surface of the applied acrylic pressure-sensitive adhesive composition is peeled off. The coating was performed so as to be on the coating layer side. Thereby, the application layer (acrylic adhesive composition layer) of the acrylic adhesive composition was shielded from oxygen. The coating layer thus obtained was irradiated with ultraviolet rays having an illuminance of 5 mW / cm ² (measured with Topcon UVR-T1 having a maximum sensitivity of about 350 nm) for 360 seconds using a chemical light lamp (manufactured by Toshiba Corporation). To obtain an acrylic pressure-sensitive adhesive layer. The polyester film coated on both sides of the pressure-sensitive adhesive layer functions as a release liner.

(Example 2)
Example 1 except that 0.1 part by mass of (meth) acrylic polymer (C) 1 was used and 0.5 part by mass of (meth) acrylic polymer (C) 1 was used. Similarly, an acrylic pressure-sensitive adhesive composition was prepared, and an acrylic pressure-sensitive adhesive layer was obtained in the same manner as in Example 1.

Example 3
Instead of using 4 parts by mass of (meth) acrylic polymer (B) 1, acrylic type was used in the same manner as in Example 1 except that 8 parts by mass of (meth) acrylic polymer (B) 1 was used. The pressure-sensitive adhesive composition was prepared, and an acrylic pressure-sensitive adhesive layer was obtained in the same manner as in Example 1.

Example 4
Example 1 except that 0.1 part by mass of (meth) acrylic polymer (C) 2 was used instead of 0.1 part by mass of (meth) acrylic polymer (C) 1 Similarly, an acrylic pressure-sensitive adhesive composition was prepared, and an acrylic pressure-sensitive adhesive layer was obtained in the same manner as in Example 1.

(Example 5)
Instead of using 4 parts by mass of (meth) acrylic polymer (B) 1, 4 parts by mass of (meth) acrylic polymer (B) 2 and (meth) acrylic polymer (C ) Acrylic pressure-sensitive adhesive composition as in Example 1 except that 0.1 part by mass of 1 was used and 0.5 part by mass of (meth) acrylic polymer (C) 1 was used. An acrylic pressure-sensitive adhesive layer was obtained by the same method as in Example 1.

(Example 6)
Example 1 except that 0.1 part by mass of (meth) acrylic polymer (C) 1 was used and 0.5 part by mass of (meth) acrylic polymer (C) 3 was used. Similarly, an acrylic pressure-sensitive adhesive composition was prepared, and an acrylic pressure-sensitive adhesive layer was obtained in the same manner as in Example 1.

(Example 7)
Example 1 except that 0.1 part by mass of (meth) acrylic polymer (C) 1 was used and 0.5 part by mass of (meth) acrylic polymer (C) 4 was used. Similarly, an acrylic pressure-sensitive adhesive composition was prepared, and an acrylic pressure-sensitive adhesive layer was obtained in the same manner as in Example 1.

(Example 8)
Example 1 except that 0.1 part by mass of (meth) acrylic polymer (C) 1 was used and 0.5 part by mass of (meth) acrylic polymer (C) 5 was used. Similarly, an acrylic pressure-sensitive adhesive composition was prepared, and an acrylic pressure-sensitive adhesive layer was obtained in the same manner as in Example 1.

Example 9
Example 1 except that 0.1 part by mass of (meth) acrylic polymer (C) 1 was used and 0.5 part by mass of (meth) acrylic polymer (C) 6 was used. Similarly, an acrylic pressure-sensitive adhesive composition was prepared, and an acrylic pressure-sensitive adhesive layer was obtained in the same manner as in Example 1.

(Example 10)
Example 1 except that 0.1 part by mass of (meth) acrylic polymer (C) 1 was used and 0.5 part by mass of (meth) acrylic polymer (C) 7 was used. Similarly, an acrylic pressure-sensitive adhesive composition was prepared, and an acrylic pressure-sensitive adhesive layer was obtained in the same manner as in Example 1.

(Example 11)
Example 1 except that 0.1 part by mass of (meth) acrylic polymer (C) 1 was used instead of 0.1 part by mass of (meth) acrylic polymer (C) 1. Similarly, an acrylic pressure-sensitive adhesive composition was prepared, and an acrylic pressure-sensitive adhesive layer was obtained in the same manner as in Example 1.

(Example 12)
Instead of using (meth) acrylic polymer 1, an acrylic pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that (meth) acrylic polymer 2 was used. An acrylic pressure-sensitive adhesive layer was obtained by the method.

(Comparative Example 1)
Acrylic pressure-sensitive adhesive composition as in Example 1 except that (meth) acrylic polymer (B) 1 and (meth) acrylic polymer (C) 1 were not used and 0.12 parts by mass of TMPTA was added. The thing was adjusted and the acrylic adhesive layer was obtained by the method similar to Example 1. FIG.

(Comparative Example 2)
Example 1 except that 0.1 part by mass of (meth) acrylic polymer (C) 9 was used instead of 0.1 part by mass of (meth) acrylic polymer (C) 1. Similarly, an acrylic pressure-sensitive adhesive composition was prepared, and an acrylic pressure-sensitive adhesive layer was obtained in the same manner as in Example 1.

(Comparative Example 3)
Instead of using (meth) acrylic polymer (B) and using 0.1 part by mass of (meth) acrylic polymer (C) 1, 5 (meth) acrylic polymer (C) 1 was used. An acrylic pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that 0.1 part by mass of TMPTA was used and 0.15 parts by mass of TMPTA was added, and an acrylic pressure-sensitive adhesive layer was obtained in the same manner as in Example 1.

(Comparative Example 4)
Instead of using (meth) acrylic polymer (C) 1 and using 4 parts by weight of (meth) acrylic polymer (B) 1, 1 (meth) acrylic polymer (B) 1 was used. An acrylic pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that mass parts were used and 0.07 parts by mass of TMPTA were added, and an acrylic pressure-sensitive adhesive layer was obtained in the same manner as in Example 1.

(Comparative Example 5)
Instead of using (meth) acrylic polymer (C) 1 and using 4 parts by mass of (meth) acrylic polymer (B) 1, 5 (meth) acrylic polymer (B) 3 was used. An acrylic pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that parts by mass were used, and an acrylic pressure-sensitive adhesive layer was obtained by the same method as in Example 1.

(Test method)
[Measurement of molecular weight]
The weight average molecular weight of the (meth) acrylic copolymer was measured using a GPC device (HLC-8220 GPC manufactured by Tosoh Corporation). 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 1 shows the measurement results of the solvent-insoluble component ratio.

[180 ° peel adhesion test]
One release liner (polyester film) of the acrylic pressure-sensitive adhesive layer according to each example and each comparative example is peeled off, and a 50 μm thick polyethylene terephthalate film is bonded to form an adhesive sheet, which is cut to a width of 25 mm Was used as a test piece. Further, a glass plate (product name: # 0050, manufactured by Matsunami Glass Industrial Co., Ltd.) having a thickness of 1.35 mm cleaned with isopropyl alcohol was prepared. Then, the other release liner (polyester film) of the pressure-sensitive adhesive sheet was peeled off, and the 2 kg roller was reciprocated once to attach the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet to the glass plate.

After sticking the pressure-sensitive adhesive sheet on the glass plate, 30 minutes later (initial stage), and after 48 hours in a 40 ° C. environment, it was allowed to stand in a 23 ° C. environment for 30 minutes (normal state). And about each adhesive sheet of an initial state and a normal condition, the other end of an adhesive sheet is peeled in the peeling direction of 180 degrees at a speed | rate of 300 mm / min, and the adhesive force (resistance force) with respect to the adherend at that time (unit: N / 25 mm). The measurement results are shown in Table 1. Based on the results of the initial adhesive strength and the normal adhesive strength, comprehensive evaluations on the rework and aging property were classified as follows.
○: Initial adhesive strength is 1.4 N / 25 mm or less and normal adhesive strength is 5.0 N / 25 mm or more. Δ: Initial adhesive strength is over 1.4 N / 25 mm and 2.0 N / 25 mm or less, and normal adhesive strength is 5.0 N / 25 mm or more x: other than above

(Transparency test: haze)
After the acrylic pressure-sensitive adhesive layer according to each Example and Comparative Example was cut to a size of 50 mm in width and 50 mm in length, one release liner was peeled off, and 1.0 mm slide glass (product number S1112) statically purified with isopropyl alcohol. : Hama was measured with a haze meter (manufactured by Murakami Color Research Laboratory Co., Ltd.) using a sample affixed to white edge polishing, Matsunami Slide Glass Co., Ltd.). A haze of less than 7% was considered good, and a haze of 7% or more was judged bad. Table 1 shows the measurement results of haze.

Claims (9)

100 parts by weight of polymer (A) having a glass transition temperature of less than 0 ° C.,
(Meth) acrylic polymer (B) having a weight average molecular weight of 1000 or more and less than 30000 and containing a monomer having a polyoxyalkylene skeleton as a monomer unit;
(Meth) acrylic polymer (C) represented by the following general formula (1) and containing a (meth) acrylic monomer having a homopolymer glass transition temperature of 0 ° C. or higher;
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 alkyl group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group]
However, the (meth) acrylic polymer (C) does not contain a polyoxyalkylene skeleton.   The pressure-sensitive adhesive composition according to claim 1, wherein the polymer (A) is an acrylic polymer. The acrylic polymer contains at least one monomer selected from the group consisting of an N-vinyl cyclic amide represented by the following general formula (M1) and a hydroxyl group-containing monomer as a monomer unit. Acrylic adhesive composition.

In the general formula (M1), R ¹ is a divalent organic group.   The pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein R2 of the (meth) acrylic monomer constituting the (meth) acrylic polymer (C) is an alicyclic hydrocarbon group. The monomer having the 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]   The adhesive layer which consists of an adhesive composition of any one of Claims 1 thru | or 5.   The pressure-sensitive adhesive layer according to claim 6, comprising 50.0 to 99.0% by mass of a solvent-insoluble component.   A pressure-sensitive adhesive sheet comprising the pressure-sensitive adhesive layer according to claim 6 or 7 formed on at least one surface of a support.   The optical film with an adhesive layer formed by forming the adhesive layer of Claim 6 or 7 in the at least single side | surface of an optical film.