JP2018002892A - Adhesive composition and application thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition having practical adhesiveness under high temperature condition and excellent reworkability and repeelability, and to provide an application thereof.SOLUTION: An adhesive composition contains a vinyl polymer (A) and an acrylic adhesive polymer (B). A second Tg that is a glass transition temperature calculated from a surface layer portion of an adhesive layer, which is obtained by coating the adhesive composition to a separator and drying the adhesive composition, obtained by X-ray photoelectron spectroscopy is higher than that the first Tg that is Tg of the whole adhesive layer by 30°C or higher. The adhesive layer has a gel fraction based on the acrylic adhesive polymer (B) of 80% or more.SELECTED DRAWING: None

Description

  The present specification relates to a pressure-sensitive adhesive composition and use thereof. More specifically, the present invention relates to a pressure-sensitive adhesive composition having excellent adhesiveness under high temperature conditions and easily peelable and pressure-sensitive adhesive products such as pressure-sensitive adhesive tapes.

  Products with a pressure-sensitive adhesive layer (hereinafter referred to as pressure-sensitive adhesive products) are widely used in various forms with a pressure-sensitive adhesive layer such as pressure-sensitive adhesive labels, pressure-sensitive adhesive sheets, and pressure-sensitive adhesive tapes, and are also used for bonding structures. ing. In general, the pressure-sensitive adhesive product is often required to have good adhesion to an adherend, but sometimes has a low adhesive strength.

  For example, a pressure-sensitive adhesive sheet for the purpose of imparting designability or advertising may be used on a car body such as an automobile such as a truck or a bus, a railway vehicle, or a window thereof. Moreover, an adhesive sheet may be used also for the purpose of displaying on an outdoor signboard or the like. In these applications, it is necessary to peel off the pressure-sensitive adhesive sheet after reworkability during a pasting operation or after a certain period of time, that is, re-peelability is required. Therefore, a pressure-sensitive adhesive whose adhesive strength at room temperature is suppressed is desired. On the other hand, such an adhesive product is often exposed to a high temperature outdoors or inside a vehicle or the like when used, and is required to have a characteristic of exhibiting good adhesiveness even under a high temperature condition.

  An adhesive having removability has already been disclosed (Patent Documents 1 and 2). Moreover, the adhesive which exhibits the favorable adhesiveness at high temperature by segregating the vinyl polymer as a tackifier on the surface layer of an adhesive layer is also disclosed (patent document 3).

JP 2002-053835 A JP 2002-338934 A JP 2014-088549 A

  However, Patent Documents 1 and 2 relate to thermal peelability that enables peeling by heat, and at the time of re-peeling, it is necessary to heat an adhesive sheet attached to a large area of a vehicle or the like. In addition, due to the property of thermal releasability, there may be a concern about poor adhesion at high temperatures. Furthermore, although the pressure-sensitive adhesive of Patent Document 3 exhibits good high-temperature adhesiveness, it is still not sufficient in terms of reworkability and removability because of high adhesiveness at room temperature.

  Therefore, the present specification provides a pressure-sensitive adhesive composition having excellent adhesiveness under high temperature conditions and excellent in reworkability and removability, and uses thereof.

  As a result of intensive studies in view of the above problems, the present inventors have paid attention to a pressure-sensitive adhesive composition capable of segregating a low molecular weight vinyl polymer as a tackifier on the surface. In this pressure-sensitive adhesive composition, the glass transition temperature of the vinyl polymer is set to a predetermined temperature or higher to control the glass transition temperature of the entire pressure-sensitive adhesive composition, and thus the glass transition temperature of the surface layer of the pressure-sensitive adhesive layer, and further control the gel fraction. As a result, it has been found that reworkability and removability can be realized simultaneously with excellent adhesiveness under high temperature conditions. According to the present specification, the following means are provided.

[1] An adhesive composition containing a vinyl polymer (A) and an acrylic adhesive polymer (B),
The vinyl polymer (A) has a glass transition temperature (Tg) of 50 ° C. or more and 200 ° C. or less, a number average molecular weight of 500 to 10,000, and 100 parts by mass of the acrylic adhesive polymer (B). 0.5 parts by mass or more and 60 parts by mass or less based on
When the pressure-sensitive adhesive composition is applied to a separator and dried to obtain a pressure-sensitive adhesive layer, the first Tg which is the glass transition temperature of the pressure-sensitive adhesive layer as a whole is −80 ° C. or more and 10 ° C. or less,
The second Tg, which is the glass transition temperature calculated from the surface layer portion obtained by X-ray photoelectron spectroscopy of the pressure-sensitive adhesive layer, is 30 ° C. or more higher than the first Tg,
The pressure-sensitive adhesive layer has a gel fraction based on the acrylic pressure-sensitive adhesive polymer (B) of 80% or more.
Adhesive composition.
[2] The pressure-sensitive adhesive composition according to [1], wherein the second Tg is 90 ° C. or more higher than the first Tg.
[3] The pressure-sensitive adhesive composition according to [1] or [2], wherein the second Tg is 40 ° C. or higher and 200 ° C. or lower.
[4] The pressure-sensitive adhesive composition according to any one of [1] to [3], wherein the vinyl polymer (A) has a Tg of 70 ° C or higher.
[5] The pressure-sensitive adhesive according to any one of [1] to [4], which contains a crosslinking agent in an amount of 0.5 to 10 parts by mass with respect to 100 parts by mass of the acrylic adhesive polymer (B). Composition.
[6] The pressure-sensitive adhesive sheet provided with a 100 μm-thick polyethylene terephthalate film base material with a pressure-sensitive adhesive layer having a thickness of 50 μm made of the pressure-sensitive adhesive composition has a peel strength of less than 10 N / 25 mm at 23 ° C. The adhesive composition according to any one of [1] to [5], wherein the peel strength of the glass plate at 85 ° C. is 10 N / 25 mm or more.
[7] An adhesive product comprising an adhesive layer,
The pressure-sensitive adhesive layer is
It is formed from an adhesive composition containing a vinyl polymer (A) and an acrylic adhesive polymer (B),
The vinyl polymer (A) has a glass transition temperature (Tg) of 50 ° C. or more and 200 ° C. or less, a number average molecular weight of 500 to 10,000, and 100 parts by mass of the acrylic adhesive polymer (B). 0.5 parts by mass or more and 60 parts by mass or less based on
1st Tg which is the glass transition temperature of the said adhesive layer whole is -80 degreeC or more and 10 degrees C or less,
The second Tg, which is the glass transition temperature calculated from the surface layer portion obtained by X-ray photoelectron spectroscopy of the pressure-sensitive adhesive layer, is 30 ° C. or more higher than the first Tg,
The pressure-sensitive adhesive layer is a pressure-sensitive adhesive product having a gel fraction based on the acrylic pressure-sensitive adhesive polymer (B) of 80% or more.
[8] The pressure-sensitive adhesive product according to [7], which is a pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape provided with the pressure-sensitive adhesive layer on one or both sides of the substrate.

  According to the pressure-sensitive adhesive composition disclosed in the present specification (hereinafter also referred to as the pressure-sensitive adhesive composition), it exhibits practical adhesiveness that can exhibit sufficient adhesiveness even at high temperatures, and at the same time, it can be reused at room temperature. A pressure-sensitive adhesive layer that also exhibits releasability can be formed. Moreover, according to this pressure-sensitive adhesive composition, a pressure-sensitive adhesive product having such a pressure-sensitive adhesive layer and excellent in peelability can be obtained.

  The present specification relates to a pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive layer capable of exhibiting practical adhesiveness, reworkability, and re-peelability at a high temperature and the like, and uses thereof.

  This pressure-sensitive adhesive composition contains a vinyl polymer (A) having a certain glass transition temperature and a number average molecular weight and an acrylic pressure-sensitive adhesive polymer (B), and the vinyl polymer (A) is used as a surface layer of the pressure-sensitive adhesive layer. It is possible to control the glass transition temperature of the surface layer of the pressure-sensitive adhesive layer by segregating. The pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive composition can simultaneously realize both high-temperature adhesiveness, reworkability at normal temperature, and removability.

  The segregation behavior of the vinyl polymer (A) on the surface of the pressure-sensitive adhesive layer when forming a pressure-sensitive adhesive layer with the present pressure-sensitive adhesive composition is determined by the specific vinyl polymer (A) and the acrylic pressure-sensitive adhesive polymer (B ) And are not completely compatible, but not completely phase separated. Preferably, the vinyl polymer (A) has a lower polarity than the acrylic adhesive polymer (B).

  As described above, the pressure-sensitive adhesive composition uses a vinyl polymer (A) that is not completely compatible with the acrylic pressure-sensitive adhesive polymer (B). At that time, the degree of segregation can be adjusted by appropriately adjusting the amount of the vinyl polymer (A) used in the pressure-sensitive adhesive composition. If the amount of the vinyl polymer (A) used is too small, segregation on the surface of the pressure-sensitive adhesive layer becomes insufficient, and a sufficient effect may not be obtained. On the other hand, when there is too much usage-amount of a vinyl polymer (A), as a result of phase-separating with an acrylic adhesive polymer (B), there exists a tendency for transparency and adhesive performance of an adhesive layer to fall. In addition, the glass transition temperature of the vinyl polymer (A), the amount of the crosslinking agent, and the like are appropriately adjusted, whereby the glass transition temperature and the gel fraction of the surface portion of the pressure-sensitive adhesive layer can be adjusted.

  Furthermore, such a pressure-sensitive adhesive layer according to the present pressure-sensitive adhesive composition can suppress the lifting and peeling of the pressure-sensitive adhesive layer even when there is outgas from the adherend at high temperatures, and can exhibit good adhesion durability.

  The segregation of the vinyl polymer (A) occurs when the pressure-sensitive adhesive layer is formed, and the vinyl polymer (A) is segregated on the surface layer side (air interface side) where the solvent evaporates. Therefore, for example, when two surface layers opposed in the thickness direction in the sheet-like or film-like pressure-sensitive adhesive layer of the present pressure-sensitive adhesive composition are in contact with a substance having a low surface energy such as a gas or a certain solid, such a substance. Pressure-sensitive adhesive layer containing vinyl polymer (A) at a higher concentration on the low surface energy interface side in contact with the pressure-sensitive adhesive layer while containing vinyl polymer (A) at a lower concentration on the central side in the thickness direction of the pressure-sensitive adhesive layer Can be obtained. That is, a pressure-sensitive adhesive layer having a gradient composition having a higher concentration of the vinyl polymer (A) on the surface layer side of the pressure-sensitive adhesive can be obtained. From the viewpoint of the acrylic pressure-sensitive adhesive polymer (B), a pressure-sensitive adhesive layer having a gradient composition having the acrylic pressure-sensitive adhesive polymer (B) at a lower concentration on the surface layer side of the pressure-sensitive adhesive layer can be obtained.

  For example, when only one surface of the two surface layers opposed in the thickness direction in the sheet-like or film-like pressure-sensitive adhesive layer of the present pressure-sensitive adhesive composition is the low surface energy interface side, A pressure-sensitive adhesive layer containing the coalescence (A) at a higher concentration can be obtained.

  Hereinafter, the disclosure of this specification will be described in detail. In the present specification, “(meth) acryl” means acryl and / or methacryl, and “(meth) acrylate” means acrylate and / or methacrylate. The “(meth) acryloyl group” means an acryloyl group and / or a methacryloyl group.

  This pressure-sensitive adhesive composition contains a vinyl polymer (A) and an acrylic pressure-sensitive adhesive polymer (B). Details of the vinyl polymer (A), the acrylic pressure-sensitive adhesive polymer (B), and the pressure-sensitive adhesive composition containing these will be sequentially described below.

[Vinyl polymer (A)]
The vinyl polymer (A) can be a polymer having a glass transition temperature (Tg) of 50 ° C. or higher and 200 ° C. or lower. The minimum with preferable Tg is 60 degreeC or more, More preferably, it is 70 degreeC or more, More preferably, it is 80 degreeC or more. Moreover, a preferable upper limit is 180 degrees C or less, More preferably, it is 150 degrees C or less, More preferably, it is 110 degrees C or less. Moreover, the more preferable range of Tg is preferably 60 ° C. or higher and 180 ° C. or lower, and more preferably 70 ° C. or higher and 150 ° C. or lower. In the present specification, a value measured by differential scanning calorimetry (DSC) at a heating rate of 10 ° C./min is adopted as Tg. When this Tg is less than 50 ° C., the Tg of the surface layer of the pressure-sensitive adhesive layer is hardly sufficiently high, and it may be difficult to obtain preferable adhesion performance and easy peelability. Further, this Tg generally does not exceed 200 ° C. due to the limitation of the raw material monomer.

  As the monomer constituting the vinyl polymer (A), various vinyl unsaturated compounds having radical polymerizability can be used. For example, (meth) acrylic acid compounds, aromatic vinyl compounds, Saturated carboxylic acid, unsaturated acid anhydride, hydroxyl group-containing unsaturated compound, amino group-containing unsaturated compound, amide group-containing unsaturated compound, alkoxyl group-containing unsaturated compound, cyano group-containing unsaturated compound, nitrile group-containing unsaturated Examples thereof include compounds and maleimide compounds. These compounds may be used alone or in combination of two or more.

  Among these, it is preferable to use a (meth) acrylic acid compound as a main component because appropriate compatibility can be obtained with respect to the acrylic adhesive polymer. The specific amount of the (meth) acrylic acid compound is preferably in the range of 10% by mass to 100% by mass, more preferably in the range of 30% by mass to 95% by mass, and more preferably in the range of 50% by mass to 90%. A range of not more than mass% is more preferred.

  (Meth) acrylic acid compounds include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, ( (Isobutyl) methacrylate, tert-butyl (meth) acrylate, amyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ( (Meth) acrylic acid alkyl esters such as (meth) acrylic acid n-dodecyl, (meth) acrylic acid n-octadecyl; (meth) acrylic acid cyclohexyl, (meth) acrylic acid methylcyclohexyl, (meth) acrylic acid t-butyl Cyclohexyl, cyclododecyl (meth) acrylate, isobornyl (meth) acrylate Aliphatic vinyl monomers such as (meth) acrylic acid adamantyl, (meth) acrylic acid dicyclopentenyl, (meth) acrylic acid dicyclopentanyl; phenyl (meth) acrylate, benzyl (meth) acrylate, etc. And aromatic ring-based vinyl polymers. These compounds may be used alone or in combination of two or more.

  Among these, (meth) acrylic acid can be set at a relatively high Tg, has a high effect of suppressing the lifting and peeling of the pressure-sensitive adhesive sheet, and has good adhesion to adherends such as olefins. Aliphatic vinyl monomers such as isobornyl, dicyclopentanyl (meth) acrylate, cyclohexyl (meth) acrylate and adamantyl (meth) acrylate can be preferably used.

  Examples of the aromatic vinyl compound include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, vinyltoluene, β-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinylxylene, vinylnaphthalene and the like. It is done. These compounds may be used alone or in combination of two or more. The amount of the aromatic vinyl compound used in the total monomer composition of the vinyl polymer (A) can be appropriately set, but is 1% by mass or more and 40% by mass with respect to the total constituent monomers of the vinyl polymer (A). % Or less, preferably 5% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 20% by mass or less.

  Unsaturated carboxylic acids include (meth) acrylic acid, ethacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, citraconic acid, cinnamic acid, and monoalkyl esters of unsaturated dicarboxylic acids (maleic acid, fumaric acid). Acid, itaconic acid, citraconic acid, maleic anhydride, itaconic anhydride, monoalkyl esters such as citraconic anhydride) and the like. These compounds may be used alone or in combination of two or more.

  Examples of the unsaturated acid anhydride include maleic anhydride, itaconic anhydride, citraconic anhydride and the like. These compounds may be used alone or in combination of two or more.

  Examples of the hydroxyl group-containing unsaturated compound include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, ( Mono (meth) acrylic acid esters of polyalkylene glycols such as 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol, polypropylene glycol, p-hydroxystyrene, m-hydroxystyrene, o -Hydroxystyrene, p-isopropenylphenol, m-isopropenylphenol, o-isopropenylphenol and the like. These compounds may be used alone or in combination of two or more.

  Examples of the amino group-containing unsaturated compound include dimethylaminomethyl (meth) acrylate, diethylaminomethyl (meth) acrylate, 2-dimethylaminoethyl (meth) acrylate, 2-diethylaminoethyl (meth) acrylate, (meth) 2- (di-n-propylamino) ethyl acrylate, 2-dimethylaminopropyl (meth) acrylate, 2-diethylaminopropyl (meth) acrylate, 2- (di-n-propylamino) (meth) acrylate Propyl, 3-dimethylaminopropyl (meth) acrylate, 3-diethylaminopropyl (meth) acrylate, 3- (di-n-propylamino) propyl (meth) acrylate, and the like. These compounds may be used alone or in combination of two or more.

  Examples of the amide group-containing unsaturated compound include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N-methylol (meth) acrylamide and the like. These compounds may be used alone or in combination of two or more.

  Examples of the alkoxyl group-containing unsaturated compound include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2- (n-propoxy) ethyl (meth) acrylate, 2- (meth) acrylic acid 2- (N-butoxy) ethyl, 3-methoxypropyl (meth) acrylate, 3-ethoxypropyl (meth) acrylate, 2- (n-propoxy) propyl (meth) acrylate, 2- (n) (meth) acrylate -Butoxy) propyl and the like. These compounds may be used alone or in combination of two or more.

  As the cyano group-containing unsaturated compound, cyanomethyl (meth) acrylate, 1-cyanoethyl (meth) acrylate, 2-cyanoethyl (meth) acrylate, 1-cyanopropyl (meth) acrylate, (meth) acrylic acid 2 -Cyanopropyl, 3-cyanopropyl (meth) acrylate, 4-cyanobutyl (meth) acrylate, 6-cyanohexyl (meth) acrylate, 2-ethyl-6-cyanohexyl (meth) acrylate, (meth) Examples include 8-cyanooctyl acrylate. These compounds may be used alone or in combination of two or more.

  Examples of the nitrile group-containing unsaturated compound include (meth) acrylonitrile, ethacrylonitrile, α-ethylacrylonitrile, α-isopropylacrylonitrile, α-chloroacrylonitrile, α-fluoroacrylonitrile and the like. These compounds may be used alone or in combination of two or more.

  As maleimide compounds, maleimide, N-methylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-dodecylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N- (2-methylphenyl) maleimide, N- (4-methylphenyl) maleimide, N- (2,6-dimethylphenyl) maleimide, N- (2,6-diethylphenyl) maleimide, N-benzylmaleimide, N-naphthylmaleimide and the like. These compounds may be used alone or in combination of two or more.

  In addition to the above compounds, dialkyl esters of unsaturated dicarboxylic acids, vinyl ester compounds, vinyl ether compounds and the like can also be used. Examples of the dialkyl ester of unsaturated dicarboxylic acid include dialkyl esters such as maleic acid, fumaric acid, itaconic acid, citraconic acid, maleic anhydride, itaconic anhydride, and citraconic anhydride. Examples of the vinyl ester compound include methylene aliphatic monocarboxylic acid ester, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl butyrate, vinyl benzoate, vinyl formate, and vinyl cinnamate. Examples of the vinyl ether compound include vinyl methyl ether, vinyl ethyl ether, vinyl n-butyl ether, vinyl isobutyl ether, vinyl phenyl ether, vinyl cyclohexyl ether and the like.

  The number average molecular weight (Mn) of the vinyl polymer (A) can be 500 or more and 10,000 or less. Preferably they are 500 or more and 7,000 or less, More preferably, they are 1,000 or more and 5,000 or less. When Mn exceeds 10,000, the compatibility with the acrylic adhesive polymer (B) is deteriorated. On the other hand, in order to produce a polymer having an Mn of less than 500, there are problems such as using a large amount of a polymerization initiator and a chain transfer agent and causing a decrease in productivity.

  Further, the ratio (Mw / Mn) between the weight average molecular weight (Mw) and the above (Mn) is preferably 3.0 or less, more preferably 2.5 or less, from the viewpoint that good adhesive strength is easily obtained. 2.0 or less is more preferable, and 1.8 or less is more preferable.

  Here, the weight average molecular weight Mw and the number average molecular weight Mn are standard polystyrene conversion values obtained using gel permeation chromatography (GPC).

  The vinyl polymer (A) of the present invention is not particularly limited with respect to its production method, but can be easily obtained by polymerizing the above monomers by employing a known radical polymerization method such as a solution polymerization method, for example. be able to. In the case of the solution polymerization method, an organic solvent and a vinyl monomer raw material are charged into a reactor, a thermal polymerization initiator such as an organic peroxide or an azo compound is added, and the mixture is heated to 50 to 300 ° C. for copolymerization. As a result, the intended vinyl polymer can be obtained. The vinyl polymer may be used as a solution dissolved in an organic solvent, or may be used by distilling off the solvent by heating and decompression treatment or the like.

  The charging method of each raw material including the monomer may be batch initial batch charging in which all raw materials are charged at once, or semi-continuous charging in which at least one raw material is continuously fed into the reactor. A continuous polymerization method in which the raw materials are continuously supplied and the product resin is continuously withdrawn from the reactor may be used.

  As the organic solvent used in the solution polymerization method, organic hydrocarbon compounds are suitable, cyclic ethers such as tetrahydrofuran and dioxane, aromatic hydrocarbon compounds such as benzene, toluene and xylene, ethyl acetate and butyl acetate and the like. Examples include esters, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, and alcohols such as methyl orthoformate, methyl orthoacetate, methanol, ethanol, and isopropanol. One or more of these can be used. Among these polymerization solvents, ethyl acetate, butyl acetate, acetone, and methyl ethyl ketone, which have a relatively low boiling point so as to dissolve the vinyl polymer well and facilitate purification, are preferable.

  The initiator used in the present invention may be an azo compound, an organic peroxide, an inorganic peroxide, or the like, but is not particularly limited. You may use the redox type polymerization initiator which consists of a well-known oxidizing agent and a reducing agent. Similarly, known chain transfer agents can be used in combination.

  As the azo compound, 2,2′-azobis (isobutyronitrile), 1,1-azobis (cyclohexane-1-carbonitrile), azocumene, 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobisdimethylvaleronitrile, 4,4′-azobis (4-cyanovaleric acid), 2- (tert-butylazo) -2-cyanopropane, 2,2′-azobis (2,4,4) -Trimethylpentane), 2,2'-azobis (2-methylpropane), dimethyl 2,2'-azobis (2-methylpropionate) and the like.

  Examples of the organic peroxide include cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, , 1-bis (tert-butylperoxy) cyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroper Oxide, 1,3-bis (tert-butylperoxy) -m-isopropyl) benzene, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, diisopropylbenzene peroxide, tert-butyl kumi Luperoxide, Decanoy Peroxide, lauroyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, bis (tert-butylcyclohexyl) peroxydicarbonate, tert-butylperoxybenzoate, 2,5-dimethyl-2,5-di (Benzoylperoxy) hexane and the like.

  Examples of inorganic peroxides include potassium persulfate, sodium persulfate, and ammonium persulfate. Redox polymerization initiators include sodium sulfite, sodium thiosulfate, sodium formaldehyde sulfoxylate, ascorbic acid, ferrous sulfate, etc. as reducing agents, potassium peroxodisulfate, hydrogen peroxide, tert-butyl hydroper What used an oxide etc. as an oxidizing agent can be used.

  The vinyl polymer (A) of the present invention can also be obtained by continuous polymerization in a temperature range of 180 to 350 ° C. using a stirred tank reactor. In this polymerization method, since a relatively low molecular weight vinyl polymer can be obtained without substantially using a polymerization initiator or a chain transfer agent, a polymer having a high purity is obtained. However, it is preferable because it is advantageous. When the polymerization temperature is lower than 180 ° C., a polymerization initiator and a large amount of chain transfer agent are required for the polymerization reaction, and the obtained copolymer is easily colored and generates an unpleasant odor. On the other hand, when the polymerization temperature exceeds 350 ° C., a decomposition reaction is likely to occur during the polymerization reaction, and the resulting copolymer is colored, so that the transparency of the pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive composition containing this is lowered. Is concerned. Furthermore, according to such a polymerization method, a vinyl polymer having a small molecular weight distribution range can be obtained. The polymerization initiator may be optionally used, but it is preferably used at about 1% by weight or less based on the total monomers.

[Acrylic adhesive polymer (B)]
The acrylic adhesive polymer (B) is a polymer containing (meth) acrylic acid esters as main structural units. The glass transition temperature (Tg) of the acrylic adhesive polymer (B) is preferably a polymer having adhesiveness in the range of −80 ° C. to 0 ° C., and the range of −80 ° C. to −20 ° C. More preferably, the range of −80 ° C. or higher and −30 ° C. or lower is more preferable, and the range of −80 ° C. or higher and −40 ° C. or lower is still more preferable. When Tg is less than −80 ° C., the cohesive force of the obtained pressure-sensitive adhesive tends to be insufficient, and curved surface adhesion and the like tend to deteriorate. When it exceeds 0 ° C., step followability and adhesive strength at low temperatures, etc. May not be enough.

  Further, the acrylic tacky polymer (B) preferably has a weight average molecular weight (Mw) of 100,000 or more and 250,000 or more from the viewpoint of exhibiting sufficient cohesive force and good adhesiveness. More preferably, it is more preferably 400,000 or more. On the other hand, if the weight average molecular weight is too high, handling in production may be difficult. Therefore, the upper limit is preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,000,000 or less.

  As a monomer constituting the acrylic adhesive polymer (B), an alkyl (meth) acrylate having an alkyl group having 4 to 12 carbon atoms in that an acrylic copolymer having a low Tg and having an adhesive property is obtained. Examples thereof include esters and alkoxyalkyl (meth) acrylates having a C2-C12 alkoxyalkyl group, and one or more of these can be used.

  Examples of the (meth) acrylic acid alkyl ester having an alkyl group having 4 to 12 carbon atoms include n-butyl (meth) acrylate, isobutyl (meth) acrylate, n-hexyl (meth) acrylate, and (meth) acrylic. N-octyl acid, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, (meth) acrylic Examples of preferred monomers include n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, and (meth). Examples include n-nonyl acrylate and isononyl (meth) acrylate.

  Examples of the alkoxyalkyl (meth) acrylate having an alkoxyalkyl group having 2 to 12 carbon atoms include methoxymethyl (meth) acrylate, ethoxymethyl (meth) acrylate, butoxymethyl (meth) acrylate, and (meth) acrylic. Examples include methoxyethyl acid, ethoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, methoxybutyl (meth) acrylate, ethoxybutyl (meth) acrylate, butoxybutyl (meth) acrylate, and the like. Among these, it is preferable to use a (meth) acrylic acid alkoxyalkyl ester having a C2-C8 alkoxyalkyl group from the viewpoint that segregation of the vinyl polymer (A) is likely to occur. It is more preferable to use (meth) acrylic acid alkoxyalkyl ester having an alkoxyalkyl group.

  The amount of (meth) acrylic acid alkyl ester having 4 to 12 carbon atoms and / or (meth) acrylic acid alkoxyalkyl having 2 to 12 carbon atoms is the total amount of acrylic copolymer. 30 mass% or more and 100 mass% or less are preferable on the basis of a constituent monomer, and 50 mass% or more and 99 mass% or less are still more preferable. When the amount is less than 30% by mass, the resulting adhesive composition has insufficient adhesive strength, tackiness, low-temperature adhesiveness, and the like.

The acrylic adhesive polymer (B) contains other monomers copolymerizable with the above (meth) acrylic acid alkyl ester and / or (meth) acrylic acid alkoxyalkyl as long as the adhesive performance is not impaired. Can be used. Examples of the copolymerizable monomer include α, β-ethylenically unsaturated carboxylic acid monomers such as (meth) acrylic acid, itaconic acid, maleic acid and fumaric acid; methyl (meth) acrylate, (meth ) (Meth) acrylic acid alkyl ester having an alkyl group having 1 to 3 carbon atoms such as ethyl acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, etc .; styrene, α-methylstyrene, vinyltoluene, etc. Vinyl aromatic monomers such as cyclohexyl (meth) acrylate, methyl cyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, isobornyl (meth) acrylate, etc. Aliphatic cyclic vinyl monomer; unsaturated dicarbonate such as itaconic acid monoethyl ester, fumaric acid monobutyl ester Monoalkyl ester of boric acid; 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate And hydroxyl group-containing monomers such as polyethylene-polypropylene glycol mono (meth) acrylate; ethylenically unsaturated carboxylic acid amides such as acrylamide, N-methylolacrylamide, N-methoxymethylacrylamide, N-methoxybutylacrylamide, and N-substituted compounds Unsaturated alcohols such as allyl alcohol; (meth) acrylonitrile, vinyl acetate, glycidyl (meth) acrylate, diacetone acrylamide, etc., and one of these It is possible to use more than seeds.
In addition, a polyfunctional polymerizable monomer having two or more polymerizable functional groups such as a (meth) acryloyl group and an alkenyl group in the molecule may be used.
Polyfunctional (meth) acrylate compounds include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di ( Di (meth) acrylates of dihydric alcohols such as (meth) acrylate; trimethylolpropane tri (meth) acrylate, trimethylolpropane ethylene oxide modified tri (meth) acrylate, glycerin tri (meth) acrylate, pentaerythritol tri ( Poly (meth) acrylates such as tri (meth) acrylates and tetra (meth) acrylates of trihydric or higher polyhydric alcohols such as (meth) acrylates and pentaerythritol tetra (meth) acrylates Mention may be made of the rate, and the like.
Examples of polyfunctional alkenyl compounds include trimethylolpropane diallyl ether, pentaerythritol diallyl ether, pentaerythritol triallyl ether, tetraallyloxyethane, polyallyl saccharose, and the like; polyfunctional allyl compounds such as diallyl phthalate; Examples thereof include bisamides such as bisacrylamide and hydroxyethylenebisacrylamide; polyfunctional vinyl compounds such as divinylbenzene.
Examples of the compound having both (meth) acryloyl group and alkenyl group include allyl (meth) acrylate, isopropenyl (meth) acrylate, butenyl (meth) acrylate, pentenyl (meth) acrylate, (meth) acrylic acid. 2- (2-vinyloxyethoxy) ethyl and the like can be mentioned.

  The acrylic adhesive polymer (B) can also be obtained by a known radical polymerization method such as a solution polymerization method, a suspension polymerization method, or an emulsion polymerization method.

[Adhesive composition]
This adhesive composition can contain a vinyl polymer (A) and an acrylic adhesive polymer (B). The vinyl polymer (A) has appropriate compatibility with the acrylic adhesive polymer (B). For this reason, the pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive composition containing them exhibits good transparency, and part of the vinyl polymer (A) is segregated in the pressure-sensitive adhesive layer, and the vinyl polymer (A ) May be higher than other portions.

  As described above, when the vinyl polymer (A) concentration in the surface layer of the pressure-sensitive adhesive layer is higher than others, the pressure-sensitive adhesive layer in the vicinity of the adhesive interface has a relatively high Tg. Can exhibit excellent adhesiveness. In addition, the pressure-sensitive adhesive sheet can be prevented from floating or peeling off due to outgas generated from the adherend. In addition to the segregation behavior of the vinyl polymer (A) in the present pressure-sensitive adhesive composition, the Tg difference between the surface layer of the pressure-sensitive adhesive layer described later and the present pressure-sensitive adhesive composition is a vinyl polymer (A) with respect to the acrylic pressure-sensitive adhesive polymer (B) ( In addition to the blending ratio of A), the monomer composition (polarity) and molecular weight of the vinyl polymer (A), it can be adjusted by appropriately setting Tg, Mw / Mn, and the like.

  This pressure-sensitive adhesive composition can contain 0.5 parts by mass or more and 60 parts by mass or less of the vinyl polymer (A) in terms of solid content with respect to 100 parts by mass of the acrylic adhesive polymer (B). The preferable content is 1 part by mass or more, more preferably 3 parts by mass or more, and still more preferably 4 parts by mass or more. Moreover, it is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and further preferably 30 parts by mass or less. Moreover, Preferably they are 1 mass part or more and 40 mass parts or less, More preferably, they are 3 mass parts or more and 30 mass parts or less. When the amount of the vinyl polymer (A) used is less than 0.5 parts by mass, the segregation of the vinyl polymer (A) in the pressure-sensitive adhesive layer is insufficient, and particularly satisfactory results cannot be obtained in high-temperature adhesiveness. On the other hand, when the amount exceeds 60 parts by mass, the vinyl polymer (A) is excessively segregated, and as a result, the adhesiveness including the step following property and the initial adhesive force (tack) may be insufficient. Moreover, it may phase-separate with an acrylic adhesive polymer (B), and the transparency of an adhesive layer may fall.

[Tg of first pressure-sensitive adhesive layer formed from the present pressure-sensitive adhesive composition (first Tg)]
The glass transition temperature (Tg) of the entire pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition, that is, the first Tg can be set in the range of −80 ° C. or higher and 10 ° C. or lower. Preferably, it is -70 degreeC or more, More preferably, it is -60 degreeC or more. Moreover, it is preferable that 1st Tg is 0 degrees C or less, More preferably, it is -10 degrees C or less, It is further more preferable that it is -20 degrees C or less. Preferably it is -70 degreeC or more and -20 degrees C or less. When Tg is less than −80 ° C., the cohesive force of the obtained pressure-sensitive adhesive is insufficient, and the curved surface adhesion and the like tend to deteriorate. When it exceeds 10 ° C., the step following property and the adhesive strength under low temperature conditions Etc. may not be sufficient. In addition, Tg of this adhesive composition can obtain temperature increase temperature 10 degree-C / min and nitrogen atmosphere as measurement atmosphere in DSC.

[Tg calculated from the composition of the surface layer portion of the pressure-sensitive adhesive layer (second Tg)]
The second Tg of the pressure-sensitive adhesive composition, that is, the pressure-sensitive adhesive layer obtained by X-ray photoelectron spectroscopy when the pressure-sensitive adhesive composition is applied to a separator and dried to obtain a pressure-sensitive adhesive layer. Tg calculated from the composition of the surface layer portion (“Tg calculated from the composition of the surface layer portion”) is a vinyl polymer (A) obtained from X-ray photoelectron spectroscopy (XPS) and an acrylic adhesive polymer (B). And can be taken as Tg of the composition forming the surface layer from the surface of the pressure-sensitive adhesive layer to the depth of about 5 nm. The details of the measurement method can follow the operations described in the examples described later.

  The second Tg is not particularly limited, but is preferably 40 ° C. or higher. The second Tg is 30 ° C. or more higher than the first Tg, so that easy peelability near normal temperature can be secured. However, the second Tg is 40 ° C. or more, so that easy peelability is realized more reliably. can do. Preferably 2nd Tg is 50 degreeC or more, More preferably, it is 60 degreeC or more, More preferably, it is 70 degreeC or more. In addition, 2nd Tg can be suitably adjusted with Tg, a compounding ratio, etc. of a vinyl polymer (A).

[Difference between Tg (first Tg) of the entire pressure-sensitive adhesive layer and Tg (second Tg) calculated from the composition of the surface layer portion of the pressure-sensitive adhesive layer]
In the present pressure-sensitive adhesive composition, the second Tg (Tg calculated from the composition of the surface layer portion of the pressure-sensitive adhesive layer) may be 30 ° C. or more higher than the first Tg (Tg of the entire pressure-sensitive adhesive layer). preferable. According to the pressure-sensitive adhesive layer having such a Tg composition, the higher the temperature of the pressure-sensitive adhesive layer of the conventional general pressure-sensitive adhesive, the lower the adhesiveness, whereas high adhesion even in a high temperature range exceeding 80 ° C. Can demonstrate its sexuality.

  Further, when the second Tg is higher than the first Tg by 30 ° C. or more, a transparent plastic substrate such as polycarbonate and polymethyl methacrylate is used as an adherend, and this is exposed to high temperature and high humidity. However, floating and peeling at the adhesive interface with the pressure-sensitive adhesive layer due to bubbles (foaming) generated from a plastic substrate or the like are suppressed, and good durability is exhibited.

  The second Tg is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, more preferably 70 ° C. or higher, still more preferably 80 ° C. or higher, more preferably 85 ° C. or higher than the first Tg. Higher, more preferably 90 ° C or higher, even more preferably 95 ° C or higher, and still more preferably 100 ° C or higher. The second Tg may be about 200 ° C. higher than the first Tg, about 180 ° C. higher, or about 160 ° C. higher.

[Mass fraction (A / A + B) of vinyl polymer (A) with respect to the total mass of vinyl polymer (A) and acrylic adhesive polymer (B) in the surface portion of the pressure-sensitive adhesive layer]
In measuring the second Tg, composition analysis by X-ray photoelectron spectroscopic analysis of the surface layer of the pressure-sensitive adhesive layer is performed. At this time, the mass fraction of the vinyl polymer (A) in the surface layer can be obtained. This mass fraction can be used as an index of the segregation state of the vinyl polymer (A) in the surface layer portion of the pressure-sensitive adhesive layer.

  For example, the mass fraction is preferably 55% or more and 95% or less. Within this range, segregation to the surface layer portion of the vinyl polymer (A) occurs, and curved surface adhesion and durability can be obtained. More preferably 60% or more, still more preferably 65% or more, still more preferably 70% or more, still more preferably 75% or more, still more preferably 80% or more, and even more preferably. 85% or more, still more preferably 90% or more. Further, the mass fraction is preferably 98% or less, more preferably 95% or less.

[Gel fraction]
The pressure-sensitive adhesive layer obtained from the present pressure-sensitive adhesive composition contains the vinyl polymer (A) and the acrylic pressure-sensitive adhesive polymer (B), but the gel fraction based on the acrylic pressure-sensitive adhesive polymer (B) is It is preferable that it is 80% or more. By setting the gel fraction based on the acrylic adhesive polymer (B) to 80% or more, while maintaining the practical adhesiveness, that is, the adhesiveness at high temperature, the adhesiveness at around room temperature is lowered. , Easy peelability can be expressed. The gel fraction is preferably 83% or more, more preferably 84% or more, and further preferably 85% or more.

  If it is an expert, the gel fraction based on the acrylic adhesive polymer (B) in an adhesive layer, the kind of vinyl polymer (A) and an acrylic adhesive polymer (B), and these compounding ratios, It can be adjusted as appropriate depending on the blending amount of the crosslinking agent and the crosslinking conditions. Moreover, the said gel fraction can be calculated | required by the method of an Example description using the gel fraction of an adhesive layer, and the gel fraction of an adhesive layer can be measured with the following method, for example. . That is, the pressure-sensitive adhesive composition was applied on a 38 μm thick polyethylene terephthalate (hereinafter “PET”) separator so that the thickness after drying was 50 μm, and dried at 80 ° C. for 4 minutes. Remove the ethyl acetate and cross-link as necessary, stick a PET separator with a thickness of 38 μm different from the separator, and let stand at 40 ° C. for 5 days. Adhesive film with double-sided separator Obtain a sample. Next, 0.2 g of the pressure-sensitive adhesive was collected from the pressure-sensitive adhesive film sample, and the initial weight of the pressure-sensitive adhesive was weighed. The adhesive is immersed in 50 g of ethyl acetate and allowed to stand at room temperature for 16 hours. Thereafter, the mixture was filtered through a 200 mesh wire mesh, and the residue remaining on the mesh was dried at 80 ° C. for 3 hours and weighed. The gel fraction can be calculated from the initial weight and the remaining weight.

[Adhesion (peel strength)]
This pressure-sensitive adhesive composition is a pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition and having a thickness of 50 μm on a 100 μm-thick polyethylene terephthalate film substrate. Is preferably less than 10 N / 25 mm. By making the adhesive strength under a normal temperature condition of 23 ° C. less than 10 N / 25 mm, easy peelability at normal temperature can be obtained. More preferably, it is 9N / 25mm or less, More preferably, it is 8N / 25mm or less, More preferably, it is 7N / 25mm or less, More preferably, it is 6N / 25mm or less.

  Further, the present pressure-sensitive adhesive composition comprises polycarbonate and polymethyl at 85 ° C. and a peeling rate of 300 mm / min of a pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition and having a thickness of 50 μm on a 100 μ-thick polyethylene terephthalate film substrate. The adhesive strength to the methacrylate plate is preferably 10 N / 25 mm or more. By setting the adhesive strength under a high temperature condition of 85 ° C. to 10 N / 25 mm or more, the adhesive strength under high temperature and high humidity conditions is sufficiently high with respect to glass, so that the pressure sensitive adhesive sheet is prevented from floating and peeling off. be able to. More preferably, it is 15 N / 25 mm or more, More preferably, it is 20 N / 25 mm or more, More preferably, it is 25 N / 25 mm or less, More preferably, it is 30 N / 25 mm or less.

  Here, in producing the pressure-sensitive adhesive layer (pressure-sensitive adhesive sheet), the pressure-sensitive adhesive composition is directly applied to a polyester film substrate and dried to obtain a pressure-sensitive adhesive sheet, or once applied to a release paper or the like. Any method of transferring to a polyester film substrate after processing may be employed. Although drying may be performed at room temperature, from the viewpoint of productivity and the like, the drying is usually performed for several seconds to several tens of minutes under a heating condition of 40 to 150 ° C. using a dryer. The method is common. More specifically, after applying this pressure-sensitive adhesive composition to a PET film separator so that the thickness after drying is 50 μm, it is necessary to remove ethyl acetate by drying at 80 ° C. for 4 minutes. In accordance with the above, a 38 μm thick PET separator having a peeling force different from that of the separator is bonded, and left to stand at 40 ° C. for 5 days, and an adhesive film sample for measuring peel strength with a double-sided separator is used. Can be obtained.

  In measuring the peel strength, this adhesive film sample was further transferred to an easily adhered PET film (100 μm) to obtain an adhesive sheet for evaluation, and a glass plate (Asahi Glass Co., Ltd., Fabricec FL11A, 1 mm thickness) A pressure-sensitive adhesive sheet is bonded to the plate, and pressure bonding is performed for 20 minutes under conditions of 0.5 MPa and 50 ° C. using a desktop pressure defoaming device TBR-200 (manufactured by Chiyoda Electric Industry Co., Ltd.). Measure the 180 degree peel strength of the pressure-sensitive adhesive sheet according to JIS Z-0237 “Testing method for pressure-sensitive adhesive tape and pressure-sensitive adhesive sheet” using a strograph R type (manufactured by Toyo Seiki Co., Ltd.) at 23 ° C. or 85 ° C. Adhesive strength can be obtained.

  The pressure-sensitive adhesive layer of the present pressure-sensitive adhesive composition has high-temperature adhesion to glass as an adherend and easy peelability at room temperature. Since it is based on (distribution), regardless of the kind of the material of the adherend, it can be provided with high temperature adhesiveness and room temperature easy peelability.

(Foam resistance)
The pressure-sensitive adhesive layer obtained by the present pressure-sensitive adhesive composition has a relatively high Tg of the pressure-sensitive adhesive layer surface layer, and is excellent in adhesiveness at the interface with the adherend. For this reason, even if gas generate | occur | produces from a to-be-adhered body, the floating and peeling of an adhesive layer are suppressed.

  For example, the foam resistance can be evaluated by the following method. That is, a laminated body in which a 100 μm-thick easy-adhesive PET film was attached to one side of an adhesive film sample made of the present adhesive composition and an adherend (glass plate or polycarbonate plate) was attached to the other side was created. Then, after pressure bonding treatment at 50 ° C., 0.5 MPa, for 20 minutes, the laminate was subjected to a load for 24 hours in a 85 ° C./85% constant temperature and humidity bath, the appearance after the load was observed, and the foaming area was appropriately determined. The ratio with respect to the total area is obtained. For example, the resistance to foaming is evaluated based on whether or not the appearance changes and the foaming area is 10% of the whole.

  In addition to the vinyl polymer (A) and the acrylic tacky polymer (B) as a tackifier, the present pressure-sensitive adhesive composition includes a crosslinking agent, a tackifier, a plasticizer, an antioxidant, and an ultraviolet absorber as necessary. It can also be set as the composition containing additives, such as an agent, anti-aging agent, a flame retardant, a fungicide, a silane coupling agent, a filler, and a coloring agent.

[Crosslinking agent]
The pressure-sensitive adhesive composition can contain a crosslinking agent. The cross-linking agent is not necessarily required, but addition of the cross-linking agent is considered depending on the intended adhesive properties and the form of the present pressure-sensitive adhesive composition, for example, whether it is an emulsion form or a solution form. By containing a cross-linking agent, the cohesive strength and adhesive strength of the pressure-sensitive adhesive layer obtained from the present pressure-sensitive adhesive composition are adjusted, and further, adhesion at high temperatures and high humidity and adhesion to curved surfaces are imparted. be able to. Crosslinking agents include glycidyl compounds having two or more glycidyl groups, isocyanate compounds having two or more isocyanate groups, aziridine compounds having two or more aziridinyl groups, oxazoline compounds having an oxazoline group, metal chelate compounds, butylated melamine compounds Etc. Among these, it is preferable to use an aziridine compound, a glycidyl compound, and an isocyanate compound.

  Examples of the aziridine compound include 1,6-bis (1-aziridinylcarbonylamino) hexane, 1,1 ′-(methylene-di-p-phenylene) bis-3,3-aziridylurea, 1,1 ′-( Hexamethylene) bis-3,3-aziridylurea, ethylenebis- (2-aziridinylpropionate), tris (1-aziridinyl) phosphine oxide, 2,4,6-triaziridinyl-1,3,5-triazine , Trimethylolpropane-tris- (2-aziridinylpropionate) and the like.

  Examples of glycidyl compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerin diglycidyl ether, neopentyl glycol diglycidyl ether, and 1,6-hexanediol diglycidyl ether. , Tetraglycidylxylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, trimethylolpropane polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, etc. A glycidyl compound is mentioned.

  As the isocyanate compound, a compound having two or more isocyanate groups is preferably used. As the isocyanate compound, aromatic, aliphatic and alicyclic isocyanate compounds, and modified products (such as prepolymers) of these isocyanate compounds can be used.

  As aromatic isocyanate, diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate, tolylene diisocyanate, naphthalene diisocyanate (NDI), p-phenylene diisocyanate (PPDI), xylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), tolidine A diisocyanate (TODI) etc. are mentioned. Examples of the aliphatic isocyanate include hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), and lysine triisocyanate (LTI). Examples of the alicyclic isocyanate include isophorone diisocyanate (IPDI), cyclohexyl diisocyanate (CHDI), hydrogenated XDI (H6XDI), and hydrogenated MDI (H12MDI). The modified isocyanate includes urethane modified products, dimers, trimers, carbodiimide modified products, allophanate modified products, burette modified products, urea modified products, isocyanurate modified products, oxazolidone modified products, isocyanates. Examples thereof include base end prepolymers.

  The content of the crosslinking agent is preferably 0.01 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the acrylic adhesive polymer (B). More preferably, it is 0.03 mass part or more, More preferably, it is 0.05 mass part or more. Moreover, More preferably, it is 5 mass parts or less, More preferably, it is 2 mass parts or less. Moreover, Preferably it is 0.03 mass part or more and 5 mass parts or less, More preferably, it is 0.05 mass part or more and 2 mass parts or less.

  Examples of tackifiers include rosin derivatives such as rosin ester, gum rosin, tall oil rosin, hydrogenated rosin ester, maleated rosin and disproportionated rosin ester; terpene phenol resin, α-pinene, β-pinene, limonene, etc. Mainly used are terpene resins, (hydrogenated) petroleum resins, coumarone-indene resins, hydrogenated aromatic copolymers, styrene resins, phenol resins, xylene resins, (meth) acrylic polymers, and the like.

  Examples of the plasticizer include di-n-butyl phthalate, di-n-octyl phthalate, bis (2-ethylhexyl) phthalate, di-n-decyl phthalate, diisodecyl phthalate and the like; bis (2-ethylhexyl) adipate, di-n Adipic acid esters such as octyl adipate; Sebacic acid esters such as bis (2-ethylhexyl) sebacate; di-n-butyl sebacate; Azelaic acid esters such as bis (2-ethylhexyl) azelate; Paraffins such as chlorinated paraffin Glycols such as polypropylene glycol; epoxy-modified vegetable oils such as epoxidized soybean oil and epoxidized linseed oil; phosphate esters such as trioctyl phosphate and triphenyl phosphate; phosphite esters such as triphenyl phosphite; ; Ester oligomers such as esterified products of adipic acid and 1,3-butylene glycol; low molecular weight polymers such as low molecular weight polybutene, low molecular weight polyisobutylene and low molecular weight polyisoprene; oils such as process oil and naphthenic oil Etc.

  Antioxidants include 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, stearyl-β- (3,5-di- -Tert-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 4, 4′-thiobis (3-methyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 3,9-bis [1,1-dimethyl-2- [β -(3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] 2,4,8,10-tetra Oxaspiro [5.5] undecane, 1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5 -Di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3' -Bis- (4'-hydroxy-3'-tert-butylphenyl) butyric acid] glycol ester, 1,3,5-tris (3 ', 5'-di-tert-butyl-4'-hydroxybenzyl) -Phenolic antioxidants such as -S-triazine-2,4,6- (1H, 3H, 5H) trione, tocopherols; dilauryl 3,3'-thiodipro Sulfur antioxidants such as onate, dimyristyl 3,3′-thiodipropionate, stearyl 3,3′-thiodipropionate; triphenyl phosphite, diphenylisodecyl phosphite, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenylditridecyl) phosphite, cyclic neopentanetetraylbis (octadecyl phosphite), tris (nonylphenyl) phosphite, tris (monononylphenyl) phosphite, tris (di Nonylphenyl) phosphite, diisodecylpentaerythritol diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10- (3,5-di-tert-butyl-4-hydroxybenzyl -9,10- Hydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene, tris (2,4-di-tert-butylphenyl) phos Phyto, cyclic neopentanetetrayl bis (2,4-di-tert-butylphenyl) phosphite, cyclic neopentanetetrayl bis (2,6-di-tert-butyl-4-methylphenyl) phosphite, Examples thereof include phosphorus antioxidants such as 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite.

  Examples of UV absorbers include salicylic acid UV absorbers such as phenyl salicylate, p-tert-butylphenyl salicylate, p-octylphenyl salicylate; 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy- 4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2-hydroxy-4-methoxy Benzophenone ultraviolet absorbers such as -5-sulfobenzophenone and bis (2-methoxy-4-hydroxy-5-benzoylphenyl) methane; 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- ( 2 -Hydroxy-5'-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert) -Butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2'- Hydroxy-3 ', 5'-di-tert-amylphenyl) benzotriazole, 2- (2'-hydroxy-4'-octoxyphenyl) benzotriazole, 2- [2'-hydroxy-3'-(3 " , 4 ", 5", 6 "-tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole, 2,2-methylenebis [4 (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol], 2- (2′-hydroxy-5′-methacryloxyphenyl) -2H-benzotriazole, Benzotriazole ultraviolet absorbers such as 2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol]; 2-ethylhexyl- Cyanoacrylate ultraviolet absorbers such as 2-cyano-3,3′-diphenyl acrylate and ethyl-2-cyano-3,3′-diphenyl acrylate; nickel bis (octylphenyl) sulfide, [2,2′-thiobis ( 4-tert-octylphenolate)]-n-butylamine nickel, nickel complex-3,5-di-t Examples thereof include nickel-based ultraviolet stabilizers such as ert-butyl-4-hydroxybenzyl-phosphate monoethylate and nickel-dibutyldithiocarbamate.

  Anti-aging agents include poly (2,2,4-trimethyl-1,2-dihydroquinoline), 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, 1- (N-phenylamino) ) -Naphthalene, styrenated diphenylamine, dialkyldiphenylamine, N, N′-diphenyl-p-phenylenediamine, N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-di-2-naphthyl-p- Phenylenediamine, 2,6-di-tert-butyl-4-methylphenol, mono (α-methylbenzyl) phenol, di (α-methylbenzyl) phenol, tri (α-methylbenzyl) phenol, 2,2′- Methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6- ert-butylphenol), 4,4′-butylidenebis (6-tert-butyl-3-methylphenol), 4,4′-thiobis (6-tert-butyl-3-methylphenol), 1,1-bis (4 -Hydroxyphenyl) cyclohexane, 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, 2-mercaptobenzimidazole, zinc salt of 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, Examples include nickel dibutyldithiocarbamate, tris (nonylphenyl) phosphite, dilauryl thiodipropionate, distearyl thiodipropionate.

  Flame retardants include tetrabromobisphenol A, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, hexabromobenzene, tris (2,3-dibromopropyl) isocyanurate, 2,2-bis Halogen flame retardants such as (4-hydroxyethoxy-3,5-dibromophenyl) propane, decabromodiphenyl oxide, halogen-containing polyphosphate; ammonium phosphate, tricresyl phosphate, triethyl phosphate, tris (β-chloroethyl) Phosphorus flame retardants such as phosphate, trischloroethyl phosphate, trisdichloropropyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, acidic phosphate ester, nitrogen-containing phosphorus compound; red phosphorus, tin oxide, ammonium trioxide Inorganic flame retardants such as mon, zirconium hydroxide, barium metaborate, aluminum hydroxide, magnesium hydroxide; poly (dimethoxysiloxane), poly (diethoxysiloxane), poly (diphenoxysiloxane), poly (methoxyphenoxysiloxane) Siloxane flame retardants such as methyl silicate, ethyl silicate, and phenyl silicate.

  Examples of fungicides include benzimidazole, benzothiazole, trihaloallyl, triazole, organic nitrogen sulfur compounds and the like.

  As silane coupling agents, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxy Propyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltrichlorosilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β (Aminoethyl) -γ-aminopropyltrimethoxysilane and the like can be mentioned.

  Examples of the filler include inorganic powder fillers such as calcium carbonate, titanium oxide, mica, and talc; and fibrous fillers such as glass fibers and organic reinforcing fibers.

If this adhesive composition contains a vinyl polymer (A) and an acrylic adhesive polymer (B), there will be no special restriction | limiting in the form. For example, it may be used as a form of a solvent-type pressure-sensitive adhesive composition dissolved in an organic solvent such as ethyl acetate, or a form of an emulsion-type pressure-sensitive adhesive composition in which an acrylic pressure-sensitive adhesive polymer and a tackifier are dispersed in an aqueous medium. It may be used as
In the case of a solution-type pressure-sensitive adhesive composition and an emulsion-type pressure-sensitive adhesive composition, the medium such as an organic solvent or water used is usually 20 to 80 parts by mass with respect to 100 parts by mass of the pressure-sensitive adhesive composition.

  When used as an emulsion-type pressure-sensitive adhesive, a stabilizer can be blended. This stabilizer is used for vinyl chloride such as cadmium stearate, zinc stearate, barium stearate, calcium stearate, lead dibutyltin dilaurate, tris (nonylphenyl) phosphite, triphenylphosphite, diphenylisodecylphosphite, etc. Stabilizer; di-n-octyltin bis (isooctylthioglycolate) salt, di-n-octyltin maleate polymer, di-n-octyltin dilaurate, di-n-octyltin maleate Ester salt, di-n-butyltin bismaleic acid ester salt, di-n-butyltin maleate polymer, di-n-butyltin bisoctylthioglycol ester salt, di-n-butyltin β-mercaptopropionate polymer, di -N-Butyl tin dilaure Di-n-methyltin bis (isooctyl mercaptoacetate) salt, poly (thiobis-n-butyltin sulfide), monooctyltin tris (isooctylthioglycolate), dibutyltin maleate, di-n-butyltin maleate ester・ Carboxylate and di-n-butyltin malate ester ・ Organic tin stabilizers such as mercaptides; tribasic lead sulfate, dibasic lead phosphite, basic lead sulfite, dibasic lead phthalate, silica Lead stabilizers such as lead acid, dibasic lead stearate, lead stearate; metal soap stabilizers such as cadmium soap, zinc soap, barium soap, lead soap, composite metal soap, calcium stearate Etc.

  In addition, the pressure-sensitive adhesive composition contains a monofunctional and / or polyfunctional (meth) acrylic acid monomer, a photopolymerization initiator, and the like in addition to the acrylic pressure-sensitive adhesive polymer and the tackifier. By including the composition, it may be used as a form of a so-called syrup-type photocurable pressure-sensitive adhesive composition that is cured by an active energy ray such as ultraviolet rays.

  In the case of the photocurable pressure-sensitive adhesive composition, the composition may contain an organic solvent or the like, but is generally used as a solventless type containing no solvents.

  Examples of the monofunctional (meth) acrylic acid monomers include (meth) acrylic acid alkyl esters having an alkyl group having 1 to 12 carbon atoms; (meth) acrylic acid cyclohexyl, (meth) acrylic acid dicyclopentyl, ( (Meth) acrylic esters having a cyclic structure such as isobornyl (meth) acrylate; hydroxy (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate Alkyl esters; (meth) acrylic acid and the like. These compounds may be used alone or in combination of two or more.

  Examples of the polyfunctional (meth) acrylic acid monomer include di (meth) acrylates of alkylene glycol such as butanediol di (meth) acrylate and hexanediol di (meth) acrylate; di (meth) triethylene glycol Di (meth) acrylates of polyalkylene glycols such as acrylates; trimethylolpropane tri (meth) acrylate and its ethylene oxide and / or propylene oxide modified products, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, etc. Is mentioned. In addition, a polymer (macromonomer) having a (meth) acryloyl group such as polyurethane (meth) acrylate and polyisoprene-based (meth) acrylate can also be used. Specific examples of the polyisoprene-based (meth) acrylate include an esterified product of a maleic anhydride adduct of isoprene polymer and 2-hydroxyethyl methacrylate. These compounds may be used alone or in combination of two or more.

  Examples of the photopolymerization initiator include benzoin and its alkyl ethers, acetophenones, anthraquinones, thioxanthones, ketals, benzophenones, xanthones, acylphosphine oxides, α-diketones and the like. Moreover, in order to improve the sensitivity by an active energy ray, a photosensitizer can also be used together. Examples of the photosensitizer include benzoic acid and amine photosensitizers. These can also be used in combination of two or more. As for the usage-amount of a photoinitiator and a photosensitizer, 0.01-10 mass parts is preferable with respect to 100 mass parts of monofunctional and / or polyfunctional (meth) acrylic-acid type monomers.

  As the photocurable resin composition, in addition to the photocurable adhesive composition described above, the vinyl polymer (A), a monofunctional and / or polyfunctional (meth) acrylic acid monomer, Moreover, it can be used also as a photocurable adhesive composition by a composition containing a photoinitiator. The said acrylic adhesive polymer (B) can be mixed with the said photocurable adhesive composition as needed.

[Production of pressure-sensitive adhesive composition]
If this adhesive composition contains a vinyl polymer (A) and an acrylic adhesive polymer (B) in the specified amount, there are no particular restrictions on the mixing method. For example, the pressure-sensitive adhesive composition may be obtained by mixing a vinyl polymer (A) and an acrylic adhesive polymer (B), or an acrylic adhesive polymer (B) in the presence of the vinyl polymer (A). ) May be polymerized to obtain the present pressure-sensitive adhesive composition.

  The present pressure-sensitive adhesive composition can be obtained by adjusting the Tg (first Tg) of the whole pressure-sensitive adhesive composition, the Tg (second Tg) of the surface layer when forming the pressure-sensitive adhesive layer, and the gel fraction. That is, a person skilled in the art will realize the first Tg and the second Tg in order to realize the adhesiveness (that is, practical adhesiveness and easy peelability) of the pressure-sensitive adhesive layer to be finally obtained. For the purpose of the temperature difference and the gel fraction, the vinyl polymer (A) and the acrylic pressure-sensitive adhesive polymer (B) are appropriately selected and blended based on the teaching of the present specification to prepare the pressure-sensitive adhesive composition. Can be obtained.

  The pressure-sensitive adhesive composition is prepared by, for example, dissolving a vinyl polymer (A) in a solvent such as ethyl acetate to prepare a polymer solution, and adding a polymer of an acrylic pressure-sensitive adhesive polymer (B) to the polymer solution. It can be produced by mixing the solution and, if necessary, mixing a crosslinking agent.

[Adhesive products]
This pressure-sensitive adhesive composition can constitute a pressure-sensitive adhesive layer of various pressure-sensitive adhesive products. A pressure-sensitive adhesive product including a pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive composition can have practical adhesion and easy peelability.

  That is, the pressure-sensitive adhesive layer included in the pressure-sensitive adhesive product is a composition derived from the pressure-sensitive adhesive composition, the first Tg of the whole pressure-sensitive adhesive composition, the second Tg calculated from the composition of the surface layer portion of the pressure-sensitive adhesive layer, These temperature differences and the gel fraction of the pressure-sensitive adhesive layer can be provided. Further, preferably, the aforementioned peel strength (23 ° C. and 85 ° C.) can be provided.

  When applying this pressure-sensitive adhesive composition to pressure-sensitive adhesive products, the pressure-sensitive adhesive composition is coated on one or both surfaces of various substrates, dried, and irradiated with an active energy ray such as UV to cause a crosslinking reaction. Thus, an adhesive layer can be formed to produce an adhesive product such as an adhesive sheet or an adhesive tape. In addition, well-known means, such as a knife coater, a roll coater, a die coater, and a bar coater, can be used as the application means. Drying is usually performed at a temperature of 60 to 180 ° C. The drying time is usually several tens of seconds to several minutes. Crosslinking is performed by aging (aging) for a predetermined time at room temperature or applying heat or active energy rays. Moreover, the product which has an adhesion layer can also be obtained by making this adhesive composition into a molten state, applying to a base material, and cooling.

  As the substrate, papers, films, cloths, nonwoven fabrics, metal foils, and the like can be used. The pressure-sensitive adhesive composition may be applied directly to these substrates, or applied to a release paper or the like. After being worked and dried, it may be transferred to a substrate. The thickness (thickness after drying) of the pressure-sensitive adhesive formed on the pressure-sensitive adhesive sheet is selected depending on the application, but is usually in the range of 1 to 300 μm, preferably in the range of 5 to 250 μm, and further in the range of 10 to 200 μm. preferable.

  Although it does not specifically limit as an adhesive product, It can use suitably for various general adhesive products, such as an adhesive film, an adhesive sheet, an adhesive tape, and a label, Especially, an adhesive product which is scheduled to peel after use for a fixed period. . Specific examples of the adhesive processed product include an adhesive sheet, an adhesive film, an adhesive tape, a pressure-sensitive tape, a surface protective film, a surface protective tape, a masking tape, an electrical insulating tape, and a laminate. Among them, it can be suitably used for adhesive products intended for so-called wrapping that protects and decorates the surface of various moving bodies such as trains, automobiles, airplanes, and other industrial vehicles.

  In addition, since the present pressure-sensitive adhesive composition is excellent in transparency and moist heat whitening resistance and has high tack and adhesive strength with respect to various adherends including glass, a touch panel, a liquid crystal display device, and an organic EL display It is also suitable for bonding of displays such as devices and plasma display panels and various optical films used therefor. In addition to products such as pressure-sensitive adhesive sheets, it is also suitable for surface protective films and the like. Moreover, it is useful also for the adhesive use in electronic components, such as a flexible printed circuit board.

  Hereinafter, although the Example which actualized the indication of this specification is described, it is clear that the following Example does not limit the indication of this specification. In the following description, “part” means part by mass, and “%” means mass%.

  Various analyzes of the polymer obtained in this example were carried out by the methods described below.

<Solid content>
About 1 g of the measurement sample was weighed (a), then the residue after drying at 155 ° C. for 30 minutes in the ventilation dryer was measured (b) and calculated from the following formula. A weighing bottle was used for the measurement. Other operations were in accordance with JIS K 0067-1992 (chemical product weight loss and residue test method).
Solid content (%) = (b / a) × 100

<Molecular weight measurement>
The molecular weight was measured by GPC under the following conditions.
GPC: Tosoh (HLC-8120)
Column: Tosoh (TSKgel-Super MP-M x 4)
Sample concentration: 0.1%
Flow rate: 0.6 ml / min Eluent: Tetrahydrofuran Column temperature: 40 ° C
Detector: Differential refractometer (RI)
Reference material: Polystyrene

<Glass transition point (Tg)>
Tg of the vinyl polymer (A), the acrylic adhesive polymer (B) and the adhesive composition was measured by DSC under the following conditions.
DSC: manufactured by TA Instrument (Q-100)
Temperature rise: 10 ° C / min Measurement atmosphere: Nitrogen

<Polymer composition>
The polymer composition was calculated from the monomer charge and the monomer consumption by GC measurement.
GC: Made by Agilent Technologies (7820A GC System)
Detector: FID
Column: 100% dimethylsiloxane (CP-Sil 5CB) length 30m, inner diameter 0.32mm
Calculation method: Internal standard method

1. Synthetic Synthesis Example 1 of Vinyl Polymer (Synthesis of Polymer A-1)
In a four-necked flask with an internal volume of 1 liter, methyl methacrylate (hereinafter referred to as “MMA”) (45 parts by mass), styrene (hereinafter referred to as “St”) (5 parts by mass), butyl acetate (245 parts by mass) And dimethyl 2,2′-azobis (2-methylpropionate) (trade name “V-601” manufactured by Wako Pure Chemical Industries, Ltd.) (2.7 parts by mass) (2.7 parts by mass) were charged. The gas was sufficiently deaerated by bubbling with nitrogen gas, and the internal temperature of the mixed solution was raised to 90 ° C. Separately, a mixture of MMA (180 parts by mass), St (19 parts by mass), V-601 (24 parts by mass), and butyl acetate (90 parts by mass) is dropped into the flask from the dropping funnel over 5 hours. Polymerization was carried out. After completion of the dropping, the polymerization solution was dropped into hexane (6000 parts by mass) to isolate the vinyl polymer in the polymerization solution, thereby obtaining a polymer A-1. The polymer composition of the obtained polymer A-1 was calculated from the charged amount and the monomer consumption by GC measurement. As a result, it was composed of 90% by mass of MMA and 10% by mass of St. Mw5650, Mn3270, and Mw / Mn1.73. Tg was 80 ° C. The composition and analysis results of the polymer A-1 are shown in Table 1.

Synthesis Example 2 (Synthesis of Polymer A-2)
A four-necked flask with an internal volume of 1 liter is charged with a mixed solution of butyl acetate (198 parts by mass) and V-601 (1.2 parts by mass), and this mixture is sufficiently degassed by bubbling nitrogen gas. The internal temperature of the mixed solution was raised to 90 ° C. Separately, a liquid mixture consisting of MMA (165 parts by mass), isobornyl methacrylate (hereinafter referred to as “IBXMA”) (44 parts by mass), V-601 (23 parts by mass), and butyl acetate (90 parts by mass) is added from a dropping funnel. Polymerization was carried out by dropping into the flask over 5 hours. After completion of the dropping, the polymerization solution was dropped into hexane (6000 parts by mass) to isolate the vinyl polymer in the polymerization solution, thereby obtaining a polymer A-2. The composition and analysis results of the polymer A-2 are shown in Table 1.

Synthesis Example 3 (Synthesis of Polymer A-3)
A four-necked flask with an internal volume of 1 liter is charged with a mixed solution of butyl acetate (210 parts by mass) and V-601 (0.9 parts by mass), and this mixture is sufficiently degassed by bubbling with nitrogen gas. The internal temperature of the mixed solution was raised to 90 ° C. Separately, a mixture of MMA (165 parts by mass), IBXMA (44 parts by mass), V-601 (17 parts by mass), and butyl acetate (90 parts by mass) is dropped into the flask from the dropping funnel over 5 hours. Polymerization was carried out. After completion of the dropping, the polymerization solution was dropped into hexane (6000 parts by mass) to isolate the vinyl polymer in the polymerization solution, thereby obtaining a polymer A-3. The composition and analysis results of the polymer A-3 are shown in Table 1.

Synthesis Example 4 (Synthesis of Polymer A-4)
A mixed solution composed of butyl acetate (100 parts by mass) and V-601 (1.9 parts by mass) was charged into a four-necked flask having an internal volume of 0.5 liter, and the mixed solution was sufficiently bubbled with nitrogen gas. After deaeration, the internal temperature of the mixed solution was raised to 90 ° C. Separately, a mixture of MMA (44 parts by mass), IBXMA (86 parts by mass), V-601 (37 parts by mass), and butyl acetate (45 parts by mass) is dropped into the flask from the dropping funnel over 5 hours. Polymerization was carried out. After completion of dropping, the polymerization solution is dropped into a mixed solution composed of methanol (2800 parts by mass) and distilled water (700 parts by mass) to isolate the vinyl polymer in the polymerization solution, thereby obtaining a polymer A-4. It was. The composition and analysis results of the polymer A-4 are shown in Table 1.

Synthesis Example 5 (Synthesis of Polymer A-5)
A four-necked flask with an internal volume of 1 liter is charged with a mixed liquid consisting of MMA (19 parts by mass), St (11 parts by mass), butyl acetate (230 parts by mass) and V-601 (8.7 parts by mass). The mixture was sufficiently deaerated by bubbling with nitrogen gas, and the internal temperature of the mixture was raised to 90 ° C. Separately, a mixture of MMA (108 parts by mass), St (93 parts by mass), V-601 (78 parts by mass), and butyl acetate (90 parts by mass) is dropped into the flask from the dropping funnel over 5 hours. Polymerization was carried out. After completion of the dropping, the polymerization solution is dropped into a mixed solution composed of methanol (4200 parts by mass) and distilled water (1800 parts by mass) to isolate the vinyl polymer in the polymerization solution, thereby obtaining a polymer A-5. It was. The composition and analysis results of the polymer A-5 are shown in Table 1.

Synthesis Example 6
A four-necked flask with an internal volume of 1 liter is charged with a mixed liquid consisting of butyl acetate (230 parts by mass), MMA (50 parts by mass), and V-601 (11.6 parts by mass), and the mixed liquid is nitrogen gas. Was sufficiently deaerated by raising the internal temperature of the mixed solution to 90 ° C. Separately, polymerization was carried out by dropping a mixture of MMA (200 parts by mass), V-601 (46 parts by mass), and butyl acetate (90 parts by mass) from the dropping funnel into the flask over 5 hours. After completion of the dropping, the polymerization solution was dropped into hexane (6000 parts by mass) to isolate the vinyl polymer in the polymerization solution, thereby obtaining a polymer A-6. Table 1 shows the composition and analysis results of the polymer A-6.

2. Synthesis Synthesis Example 7 of Acrylic Adhesive Polymer (Synthesis of Polymer B-1)
In a four-necked flask with an internal volume of 2 liters, methoxyethyl acrylate (hereinafter referred to as “MEA”) (285 parts by mass), 2-hydroxyethyl acrylate (hereinafter referred to as “HEA”) (15 parts by mass), acetic acid Ethyl (520 parts by mass) was charged, the mixture was sufficiently degassed by bubbling nitrogen gas, the internal temperature of the mixture was raised to 40 ° C., and azobisvaleronitrile (hereinafter referred to as “V-65”). (11.5 parts by mass) was charged and polymerization was started. Four hours later, the acrylic adhesive polymer was isolated by dropping the polymerization solution into hexane (10000 parts by mass) to obtain a polymer B-1. The obtained polymer B-1 was composed of 95% by mass of MEA and 5% by mass of HEA, and had Mw of 500,000, Mn of 70,000, and Mw / Mn of 7.1. Table 2 shows the composition and analysis results of the polymer B-1.

Synthesis Example 8 (Synthesis of Polymer B-2)
MEA (255 parts by mass), butyl acrylate (hereinafter referred to as “BA”) (8 parts by mass), HEA (15 parts by mass), and ethyl acetate (520 parts by mass) were added to a 4-neck flask having an internal volume of 2 liters. The mixture was sufficiently degassed by bubbling with nitrogen gas, the internal temperature of the mixture was raised to 40 ° C., V-65 (11.4 parts by mass) was charged, and polymerization was started. Four hours later, the acrylic adhesive polymer was isolated by dropping the polymerization solution into hexane (10000 parts by mass) to obtain a polymer B-2. Obtained polymer B-2 consisted of 85 mass% of MEA, 10 mass% of BA, and 5 mass% of HEA, and was Mw 520,000, Mn 80,000, and Mw / Mn 6.5. Table 2 shows the composition and analysis results of the polymer B-2.

Synthesis Example 9 (Synthesis of polymer B-3)
MEA (188 parts by mass), BA (192 parts by mass), HEA (20 parts by mass), and ethyl acetate (740 parts by mass) are charged into a 2-liter flask having an internal volume of 2 liters, and this mixture is bubbled with nitrogen gas. Was sufficiently deaerated, the internal temperature of the mixed solution was raised to 40 ° C., V-65 (10.3 parts by mass) was charged, and polymerization was started. Four hours later, the acrylic adhesive polymer was isolated by dropping the polymerization solution into hexane (10000 parts by mass) to obtain a polymer B-3. The obtained polymer B-3 was composed of 47% by mass of MEA, 48% by mass of BA, and 5% by mass of HEA, and was Mw 510,000, Mn 90,000, and Mw / Mn 5.7. Table 2 shows the composition and analysis results of the polymer B-3.

3. Production and evaluation of pressure-sensitive adhesive composition Example 1
The polymer (A-1) obtained in Synthesis Example 1 was dissolved in ethyl acetate to prepare a polymer (A-1) solution having a solid content concentration of 30% by mass. Similarly, the polymer (B-1) obtained in Synthesis Example 7 was dissolved in ethyl acetate to prepare a polymer (B-1) solution having a solid content concentration of 30% by mass. The polymer (A-1) solution 4 parts by mass, polymer B-1 solution (100 parts by mass), Takenate D-110N (solid content concentration 75% by mass, manufactured by Mitsui Chemicals) (0.32 mass) as a crosslinking agent Part) was mixed to obtain an adhesive composition.

  This pressure-sensitive adhesive composition was applied on a 38 μm thick polyethylene terephthalate (hereinafter “PET”) separator so that the thickness after drying was 50 μm. By drying the pressure-sensitive adhesive composition at 80 ° C. for 4 minutes, ethyl acetate was removed and a crosslinking reaction was performed, and a PET separator having a thickness of 38 μm different from that of the separator was bonded, and 5 ° C. at 5 ° C. The adhesive film sample with a double-sided separator was obtained by standing for aging and aging (aging).

  The obtained adhesive film sample was subjected to various measurements and evaluations by the following methods. The obtained results are shown in Table 2.

<Gel fraction based on acrylic adhesive polymer (B)>
0.2 g of adhesive was collected from the adhesive film sample, and the initial weight of the adhesive was weighed. The adhesive is immersed in 50 g of ethyl acetate and allowed to stand at room temperature for 16 hours. Thereafter, the mixture was filtered through a 200 mesh wire mesh, and the residue remaining on the mesh was dried at 80 ° C. for 3 hours and weighed. From the initial weight and the residual weight, the gel fraction based on the acrylic adhesive polymer (B) was calculated by the following formula.
Gel fraction (%) = (weight of residue) / [(initial weight) × (solid content of acrylic adhesive polymer (B)) / (solid content of pressure-sensitive adhesive composition)] × 100

<Peel strength for glass>
The pressure-sensitive adhesive film sample was transferred to a PET film (100 μm) subjected to easy adhesion treatment to obtain a pressure-sensitive adhesive sheet for evaluation. The adherend is a glass plate (manufactured by Asahi Glass Co., Ltd., Fabricec FL11A, 1 mm thickness), and the adhesive sheet for evaluation described above is bonded together, and 0 using a tabletop pressure deaerator TBR-200 (manufactured by Chiyoda Electric Co., Ltd.). After pressure bonding under conditions of 5 MPa and 50 ° C. for 20 minutes, JISZ-0237 “adhesive tape / adhesive sheet” is used under the condition of 23 ° C. using a tensile tester “Strograph R type” (manufactured by Toyo Seiki Co., Ltd.) with a thermostatic bath. According to the “Test method”, the 180-degree peel strength of the pressure-sensitive adhesive sheet was measured and used as the adhesive strength. The peeling rate was 300 mm / min. It was.

<Tg of the surface layer portion of the pressure-sensitive adhesive layer>
From the peak area ratio of O1s and C1s measured by X-ray photoelectron spectroscopy (XPS) of the adhesive film sample, vinyl relative to the total amount of vinyl polymer (A) and acrylic adhesive polymer (B) in the surface layer portion of the adhesive layer Each mass fraction (w _A and w _B ) of the polymer (A) and the acrylic adhesive polymer ( _B ) was calculated, and the Tg of the surface layer portion was calculated based on the FOX formula.
XPS measurement was performed under the following conditions.
Apparatus: PHI5000 VersaProbe manufactured by ULVAC-PHI
X-ray: Al-Kα (1486.6 eV)
X-ray incident angle on the sample: 0 ° (angle with respect to the normal of the sample measurement surface)
Photoelectron detection angle: 45 ° (angle with respect to normal of sample measurement surface)

ここで、
（Ｏ／Ｃ）_Ａ+B：粘着剤組成物を乾燥して得られた粘着剤層のＸＰＳ測定から求められるＯ１ｓとＣ１ｓのピーク面積比
Ｗ_Ａ：ビニル重合体（Ａ）及びアクリル系粘着性ポリマー（Ｂ）の総量に対するビニル重合体（Ａ）の質量分率
Ｍ_ｗ−Ａ：ビニル重合体（Ａ）の全構成単量体単位の加重平均分子量
Ｍ_ｗ−Ｂ：アクリル系粘着剤組成物（Ｂ）の全構成単量体単位の加重平均分子量
Ｎ_Ｏ−Ａ：ビニル重合体（Ａ）を構成する全構成単量体の平均単量体構造式中に含まれる酸素原子数
Ｎ_Ｏ−Ｂ：アクリル系粘着性ポリマー（Ｂ）を構成する全構成単量体の平均単量体構造式中に含まれる酸素原子数
Ｎ_Ｃ−Ａ：ビニル重合体（Ａ）を構成する全構成単量体の平均単量体構造式中に含まれる炭素原子数
Ｎ_Ｃ−Ｂ：アクリル系粘着性ポリマー（Ｂ）を構成する全構成単量体の平均単量体構造式中に含まれる炭素原子数 A specific method for calculating the mass fraction is described below.
The peak area ratio of O1s and C1s by XPS measurement is the pressure-sensitive adhesive layer surface layer part formed from a pressure-sensitive adhesive composition comprising a vinyl polymer (A) and an acrylic pressure-sensitive adhesive polymer (B) as shown in the following formula (1). It is represented by the ratio of the number of oxygen atoms and the number of carbon atoms present per unit weight.

here,
(O / C) _{A + B} : Peak area ratio between O1s and C1s determined from XPS measurement of the pressure-sensitive adhesive layer obtained by drying the pressure-sensitive adhesive composition W _A : vinyl polymer (A) and acrylic pressure-sensitive adhesive Mass fraction _Mw-A of vinyl polymer (A) with respect to the total amount of polymer (B): Weighted average molecular weight _Mw-B of all constituent monomer units of vinyl polymer (A): Acrylic adhesive composition Weighted average molecular weight N _O-A of all constituent monomer units in (B): Number of oxygen atoms N _O— contained in the average monomer structural formula of all constituent monomers constituting the vinyl polymer (A) _B : Number of oxygen atoms contained in the average monomer structural formula of all constituent monomers constituting the acrylic adhesive polymer (B) N _C-A : All constituent single quantities constituting the vinyl polymer (A) the number of carbon atoms contained averaged in the monomer structure of the body N _C-B: acrylic adhesive polymer The average number of carbon atoms contained in the monomer structure of the total constituent monomer constituting the (B)

ここで、
（Ｏ／Ｃ）_Ａ：ビニル重合体（Ａ）を乾燥して得られたフィルムのＸＰＳ測定から求められるＯ１ｓとＣ１ｓのピーク面積比

ここで、
（Ｏ／Ｃ）_Ｂ：アクリル系粘着性ポリマー（Ｂ）を乾燥して得られたフィルムのＸＰＳ測定から求められるＯ１ｓとＣ１ｓのピーク面積比 Moreover, the peak area ratio of O1s and C1s calculated | required by the XPS measurement of the film obtained by drying each single body of a vinyl polymer (A) and an acrylic adhesive polymer (B) is following Formula (2) and ( 3).

here,
(O / C) _A : Peak area ratio of O1s and C1s determined from XPS measurement of a film obtained by drying the vinyl polymer (A)

here,
(O / C) _B : Peak area ratio of O1s and C1s determined from XPS measurement of a film obtained by drying the acrylic adhesive polymer (B)

さらに、上記で求めたＷ_Ａの値と下記式（５）から、アクリル系粘着性ポリマー（Ｂ）の質量分率（Ｗ_Ｂ）が算出される。

ここで、
Ｗ_Ｂ：ビニル重合体（Ａ）及びアクリル系粘着性ポリマー（Ｂ）の総量に対するアクリル系粘着性ポリマー（Ｂ）の質量分率 The following formula (4) is derived from the above formulas (1) to (3), and from this, the mass fraction of the vinyl polymer (A) with respect to the total amount of the vinyl polymer (A) and the acrylic adhesive polymer (B). (W _A ) is calculated.

Further, the mass fraction (W _B ) of the acrylic pressure-sensitive adhesive polymer ( _B ) is calculated from the value of W _A obtained above and the following formula (5).

here,
W _B : Mass fraction of the acrylic adhesive polymer (B) with respect to the total amount of the vinyl polymer (A) and the acrylic adhesive polymer (B)

About Example 1, each element in the said Formula (4) is shown below.
(O / C) _{A + B} : 0.3 (actual value)
(O / C) _A : 0.3 (actual value)
(O / C) _B : 0.5 (actual value)
N _C-A : From the number of carbon atoms in the MMA1 molecule (5), the number of carbon atoms in the St1 molecule (8), and the composition ratio, 5 × 90 (%) + 8 × 10 (%) = 5.3
N _C-B : From the number of carbon atoms in MEA1 molecule (6), the number of carbon atoms in HEA1 molecule (5) and the composition ratio, 6 × 94 (%) + 5 × 6 (%) = 5.9
M _w−A : From the molecular weight of MMA (100), the molecular weight of St (104), and the composition ratio, 100 × 90 (%) + 104 × 10 (%) = 100
M _w−B : From the molecular weight of MEA (130), the molecular weight of HEA (116), and the composition ratio, 130 × 94 (%) + 116 × 6 (%) = 129
By substituting these values into the equation (4), W _A = 0.8 was obtained, and from the equation (5), W _B = 0.2 was obtained.

Next, Tg of the surface layer portion was calculated from the surface composition obtained by the measurement according to the formula of FOX represented by the following formula (6), and a value of 50.3 ° C. was obtained.
1 / [Tg of surface layer portion] (K) = W _A / Tg _A + W _B / Tg _B (6)
here,
Tg _A : Tg of vinyl polymer (A) (80 ° C.)
Tg _B : Tg of acrylic adhesive polymer (B) (−31 ° C.)

<Foaming resistance>
Adhesive film sample with a thickness of 100 μm was applied to one side of the adhesive film sample, and a laminate was prepared by attaching a glass plate or a polycarbonate plate to the other side. The laminate was 50 ° C., 0.5 MPa, A crimping process for 20 minutes was performed. Thereafter, a load was applied to the laminate in a constant temperature and humidity chamber at 85 ° C./85% for 24 hours, and the appearance after the load (whether foaming was present) was visually confirmed and evaluated according to the following criteria.
○: No change in appearance △: Area of the foamed portion is 10% or less with respect to the area of the test piece ×: Area of the foamed portion exceeds 10% with respect to the area of the test piece

(Examples 2-6 and Comparative Examples 1-6)
In Example 1, the types and ratios of the acrylic pressure-sensitive adhesive polymer and the vinyl polymer were changed as shown in Tables 3 and 4 to obtain a pressure-sensitive adhesive composition, and the same measurements as in Example 1 were performed. The results are shown in Tables 3 and 4.

  As shown in Table 3 and Table 4, Examples 1 to 6 using the pressure-sensitive adhesive composition disclosed in the present specification all exhibit good peel strength (23 ° C. and 85 ° C.) and glass. Good foam resistance was exhibited for the plate and PC plate. Especially, Tg of the surface layer part of an adhesive layer is 90 degreeC or more higher than Tg of the whole adhesive layer, More preferably, it is 100 degreeC or more higher, Tg of a vinyl polymer (A) is 90 degreeC or more, When the Tg of the surface layer portion was 60 ° C. or more and the gel fraction was 80% or more, a peel strength of 6 N / 25 mm or less was exhibited at 23 ° C.

  On the other hand, in Comparative Examples 1 to 3 using a pressure-sensitive adhesive composition that does not segregate, the Tg distribution in the pressure-sensitive adhesive layer is not observed, and the peel strength at 23 ° C. is high, while the peel strength at 85 ° C. is low. In addition, the foam resistance was not sufficient. In Comparative Example 4, since the gel fraction is only 74.3%, it showed good peel strength at 85 ° C., but maintained the peel strength at 23 ° C. and could easily be peeled. could not. In Comparative Example 5, since the Tg of the vinyl polymer (A) is as low as 44 ° C. and the Tg of the surface layer portion of the pressure-sensitive adhesive layer is as low as about 30 ° C., the Tg of the surface layer portion of the pressure-sensitive adhesive layer is the entire pressure-sensitive adhesive layer. Although the peel strength at 23 ° C. was maintained and easy peelability could not be obtained, the peel strength at 85 ° C. had been lowered, although it was about 60 ° C. higher than the Tg. Further, in Comparative Example 6, the Tg of the surface layer portion of the pressure-sensitive adhesive layer and the Tg of the entire pressure-sensitive adhesive layer are similarly low, and the Tg of the surface layer portion of the pressure-sensitive adhesive layer is only 0.8 ° C. higher than the Tg of the entire pressure-sensitive adhesive layer. Therefore, neither easy peelability nor adhesiveness could be exhibited.

  The pressure-sensitive adhesive composition disclosed in the present specification can be suitably used for various general pressure-sensitive processed products such as pressure-sensitive adhesive films, pressure-sensitive adhesive sheets, pressure-sensitive adhesive tapes, and labels. Specific examples of the adhesive processed product include an adhesive sheet, an adhesive film, an adhesive tape, a pressure sensitive tape, a surface protective film, a surface protective tape, a masking tape, an electrical insulating tape, and a laminate. Especially, it is suitable for the adhesive product which coat | covers a comparatively large area, such as the exterior and interior of a moving body. In addition to the above, the pressure-sensitive adhesive composition of the present invention is excellent in transparency and moist heat resistance, and has high adhesive strength and tack to various adherends such as glass and plastic. It is also suitable for bonding displays such as organic EL display devices and plasma display panels and various optical films used in these displays.

Claims (8)

An adhesive composition comprising a vinyl polymer (A) and an acrylic adhesive polymer (B),
The vinyl polymer (A) has a glass transition temperature (Tg) of 50 ° C. or more and 200 ° C. or less, a number average molecular weight of 500 to 10,000, and 100 parts by mass of the acrylic adhesive polymer (B). 0.5 parts by mass or more and 60 parts by mass or less based on
When the pressure-sensitive adhesive composition is applied to a separator and dried to obtain a pressure-sensitive adhesive layer, the first Tg which is the glass transition temperature of the pressure-sensitive adhesive layer as a whole is −80 ° C. or more and 10 ° C. or less,
The second Tg, which is the glass transition temperature calculated from the surface layer portion obtained by X-ray photoelectron spectroscopy of the pressure-sensitive adhesive layer, is 30 ° C. or more higher than the first Tg,
The pressure-sensitive adhesive layer has a gel fraction based on the acrylic pressure-sensitive adhesive polymer (B) of 80% or more.
Adhesive composition.   2. The pressure-sensitive adhesive composition according to claim 1, wherein the second Tg is 90 ° C. or more higher than the first Tg.   The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the second Tg is 40 ° C or higher and 200 ° C or lower.   The adhesive composition in any one of Claims 1-3 whose Tg of the said vinyl polymer (A) is 70 degreeC or more.   The pressure-sensitive adhesive composition according to any one of claims 1 to 4, comprising a crosslinking agent in an amount of 0.5 to 10 parts by mass with respect to 100 parts by mass of the acrylic adhesive polymer (B).   The pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition and having a thickness of 50 μm on a 100 μm-thick polyethylene terephthalate film substrate has a peel strength of less than 10 N / 25 mm at 23 ° C., and 85 ° C. of the pressure-sensitive adhesive sheet. The pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the peel strength with respect to the glass plate is 10 N / 25 mm or more. An adhesive product comprising an adhesive layer,
The pressure-sensitive adhesive layer is
It is formed from an adhesive composition containing a vinyl polymer (A) and an acrylic adhesive polymer (B),
The vinyl polymer (A) has a glass transition temperature (Tg) of 50 ° C. or more and 200 ° C. or less, a number average molecular weight of 500 to 10,000, and 100 parts by mass of the acrylic adhesive polymer (B). 0.5 parts by mass or more and 60 parts by mass or less based on
1st Tg which is the glass transition temperature of the said adhesive layer whole is -80 degreeC or more and 10 degrees C or less,
The second Tg, which is the glass transition temperature calculated from the surface layer portion obtained by X-ray photoelectron spectroscopy of the pressure-sensitive adhesive layer, is 30 ° C. or more higher than the first Tg,
The pressure-sensitive adhesive layer is a pressure-sensitive adhesive product having a gel fraction based on the acrylic pressure-sensitive adhesive polymer (B) of 80% or more.   The pressure-sensitive adhesive product according to claim 7, which is a pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape provided with the pressure-sensitive adhesive layer on one side or both sides of a substrate.