KR102306382B1 - Adhesive composition, and adhesive sheet - Google Patents

Abstract

(assignment)
To provide an adhesive sheet which does not form a citron shell, is excellent in weather resistance, foam resistance, and rework property, and does not cause a zipping phenomenon, and to provide an adhesive composition capable of obtaining the adhesive sheet.
(Solution)
The pressure-sensitive adhesive composition of the present invention is a copolymer of a monomer component comprising a (meth)acrylic acid alkyl ester having a homopolymer of 0 ° C. or higher, a (meth) acrylic acid alkyl ester having a homopolymer of less than 0 ° C. and a carboxyl group-containing monomer (meth) ) An acrylic copolymer (A), an alkyl methacrylate ester, a (meth)acrylic copolymer (B), which is a copolymer of a monomer component containing an amino group-containing monomer, and a crosslinking agent (C) It is a pressure-sensitive adhesive composition comprising, The amount of polymerization initiator contained in 100 wt% of the solid content of the composition is 800 ppm or less.

Description

An adhesive composition and an adhesive sheet {ADHESIVE COMPOSITION, AND ADHESIVE SHEET}

The present invention relates to a pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet.

Conventionally, affixing an adhesive film on transparent plastics, for example, polycarbonate (PC) or polymethyl methacrylate (PMMA) for protection and scattering prevention is performed. Moreover, affixing an adhesion film for protection and scattering prevention of glass is also performed.

BACKGROUND ART A display of an image display device such as a liquid crystal display device is usually provided with a front plate such as a plastic plate or a glass plate on the outermost side for the purpose of protecting internal parts. An adhesive sheet for preventing scattering for preventing scattering of plastic or glass when an impact is applied and damaged may be affixed to the front plate.

The adhesive sheet for preventing scattering generally has a polyethylene terephthalate (PET) film and an adhesive layer provided on the PET film.

As an adhesive used for such an adhesive layer, weather resistance, transparency, easiness of adhesive force control, etc. are calculated|required. Moreover, since generation|occurrence|production of foaming and swelling greatly impairs the external appearance of an adhesive sheet, the property which prevents these generation|occurrence|production, ie, foaming resistance, is also calculated|required.

In order to satisfy these requirements, the adhesive provided with weather resistance, transparency, the easiness of adhesive force control, foaming resistance, etc. are proposed (for example, refer patent document 1).

In Patent Document 1, a (meth)acrylic acid alkyl ester and a resin composition (1) having a weight average molecular weight of 800,000 or more obtained by copolymerizing a copolymerizable unsaturated monomer containing a carboxyl group, and an alkyl methacrylate or cycloalkyl methacrylate ester, meth A pressure-sensitive adhesive composition comprising a resin composition (2) having a weight average molecular weight of 100,000 or less obtained by copolymerizing one or two or more monomers selected from benzyl acrylate or styrene and a copolymerizable unsaturated monomer containing an amino group is proposed. . In Patent Document 1, by combining the main polymer having a carboxyl group and a low molecular polymer having an amino group, the foaming resistance is improved by the interaction between the carboxyl group and the amino group, and there are problems in properties such as weather resistance, transparency, and ease of control of adhesive force. None is disclosed.

Japanese Patent No. 3516035

In recent years, in adhesive sheets used for scattering prevention applications, etc., in addition to performance such as weather resistance, transparency, ease of adhesive force control, foaming resistance, etc., it is required to have excellent reworkability and to improve additional physical properties with respect to that which does not cause a zipping phenomenon. .

Moreover, when manufacturing and using an adhesive sheet using the conventional adhesive composition, an adhesive layer may become what is called a citron shell shape. The pressure-sensitive adhesive sheet in the shape of a citron shell was greatly inferior in appearance, so improvement was demanded.

An object of the present invention is to provide an adhesive sheet that does not form a citron shell, is excellent in weather resistance, foam resistance, and rework property, and does not cause a zipping phenomenon, and to provide a pressure-sensitive adhesive composition capable of obtaining the adhesive sheet .

As a result of intensive studies conducted by the present inventors to solve the above problems, the polymerization initiator remaining in the pressure-sensitive adhesive composition causes a reaction in the pressure-sensitive adhesive layer due to factors such as storage of the pressure-sensitive adhesive sheet in a high-temperature environment or UV irradiation. found to be the main cause of the phenomenon. For this reason, when a pressure-sensitive adhesive composition excellent in weather resistance, that is, UV resistance, is used, it is known that the amount of residual initiator in the pressure-sensitive adhesive composition is important in order to obtain a pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer does not form a citron shell shape and to prevent the pressure-sensitive adhesive layer from becoming a citron shell shape. and completed the present invention.

That is, the present invention relates to, for example, the following [1] to [3].

[1] The glass transition temperature (Tg) of the homopolymer is 0 ° C. or higher, and the glass transition temperature (Tg) of the homopolymer is 13 to 35% by mass of (meth)acrylic acid alkyl ester having 1 to 12 carbon atoms in the alkyl group. (meth)acrylic copolymer that is less than 0 ° C., and a copolymer of a monomer component containing 55 to 80% by mass of (meth)acrylic acid alkyl ester having 1 to 12 carbon atoms in the alkyl group, and 3.5 to 10% by mass of a carboxyl group-containing monomer Copolymer (A), a (meth)acrylic copolymer (B), which is a copolymer of a monomer component containing an alkyl methacrylic acid ester having 1 to 20 carbon atoms in an alkyl group, and an amino group-containing monomer, and a crosslinking agent (C) It is a pressure-sensitive adhesive composition, and the pressure-sensitive adhesive composition contains 1 to 40 parts by mass of the (meth)acrylic copolymer (B) and 0.01 to 5 parts by mass of the crosslinking agent (C) with respect to 100 parts by mass of the (meth)acrylic copolymer (A). , The amount of the polymerization initiator contained in 100% by weight of the solid content of the pressure-sensitive adhesive composition is 800ppm or less pressure-sensitive adhesive composition.

[2] The pressure-sensitive adhesive composition according to [1], wherein the (meth)acrylic copolymer (B) has a weight average molecular weight of 1000 to 50000 and a glass transition temperature of 80°C or higher.

[3] A pressure-sensitive adhesive sheet produced from the pressure-sensitive adhesive composition according to [1] or [2].

ADVANTAGE OF THE INVENTION According to this invention, the adhesive sheet which does not form a citron shell shape, is excellent in weather resistance, foaming resistance, and rework property, and does not raise|generate a zipping phenomenon, and the adhesive composition which can obtain this adhesive sheet are provided.

Next, the present invention will be specifically described.

In the present invention, "(meth)acryl" is used in the meaning of generically naming acryl and methacryl. That is, "(meth)acrylic acid alkyl ester" is used in the generic sense of acrylic acid alkyl ester and methacrylic acid alkyl ester. In addition, "(meth)acrylate" is used in the meaning of generically naming an acrylate and a methacrylate.

[Adhesive composition]

In the pressure-sensitive adhesive composition of the present invention, the glass transition temperature (Tg) of the homopolymer is 0 ° C. or higher, and 13 to 35 mass% of (meth)acrylic acid alkylester having 1 to 12 carbon atoms in the alkyl group, the glass transition temperature of the homopolymer ( Tg) is less than 0 ° C., and 55 to 80 mass % of (meth) acrylic acid alkyl ester having 1 to 12 carbon atoms in the alkyl group, and 3.5 to 10 mass % of a carboxyl group-containing monomer, which is a copolymer of a monomer component (meth ) An acrylic copolymer (A), an alkyl methacrylic acid ester having 1 to 20 carbon atoms in the alkyl group, and a (meth)acrylic copolymer (B), which is a copolymer of a monomer component containing an amino group-containing monomer, and a crosslinking agent (C) An adhesive composition comprising The amount of the polymerization initiator contained in 100% by weight of the solid content of the pressure-sensitive adhesive composition is 800 ppm or less.

A pressure-sensitive adhesive sheet having an adhesive layer formed from the pressure-sensitive adhesive composition of the present invention is preferable because it does not have a citron shell shape, is excellent in weather resistance, foam resistance, and rework property, and does not cause a zipping phenomenon.

((meth)acrylic copolymer (A))

The pressure-sensitive adhesive composition of the present invention contains a (meth)acrylic copolymer (A). The (meth)acrylic copolymer (A) has a glass transition temperature (Tg) of the homopolymer of 0° C. or higher, and contains 13 to 35 mass of (meth)acrylic acid alkyl ester (a-1) having 1 to 12 carbon atoms in the alkyl group. %, the glass transition temperature (Tg) of the homopolymer is less than 0 ° C., and 55 to 80 mass% of (meth)acrylic acid alkyl ester (a-2) having 1 to 12 carbon atoms in the alkyl group, and a carboxyl group-containing monomer ( It is a copolymer of the monomer component containing 3.5-10 mass % of a-3).

((meth)acrylic acid alkyl ester (a-1))

The (meth)acrylic acid alkyl ester (a-1) is a (meth)acrylic acid alkyl ester having a homopolymer glass transition temperature (Tg) of 0°C or higher and having an alkyl group having 1 to 12 carbon atoms.

As (meth)acrylic acid alkylester (a-1), the glass transition temperature (Tg) of a homopolymer becomes like this. Preferably it is 0-120 degreeC, More preferably, it is 0-100 degreeC. When Tg is in the said range, it is preferable at the point which can make durability of the adhesive layer obtained high.

As (meth)acrylic-acid alkylester (a-1), carbon number of an alkyl group becomes like this. Preferably it is 1-8, More preferably, it is 1-4. Moreover, a linear alkyl group may be sufficient as an alkyl group, and the alkyl group which has a branch may be sufficient.

As a specific example of (meth)acrylic acid alkylester (a-1), methyl acrylate (Tg: 8 degreeC), n-propyl acrylate (Tg: 3 degreeC), t-butyl acrylate (Tg: 43 degreeC), pentyl acryl rate (Tg: 22 °C), methyl methacrylate (Tg: 105 °C), ethyl methacrylate (Tg: 65 °C), n-propyl methacrylate (Tg: 35 °C), isopropyl methacrylate (Tg) : 81°C), n-butyl methacrylate (Tg: 20° C.), isobutyl methacrylate (Tg: 48° C.), and t-butyl methacrylate (Tg: 118° C.).

As (meth)acrylic-acid alkylester (a-1), you may use individually by 1 type, and may use 2 or more types. Examples of the (meth)acrylic acid alkyl ester (a-1) include methyl acrylate, t-butyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and t-butyl methacrylate. The at least 1 sort(s) of monomer chosen from the rate is preferable, methyl acrylate and t-butyl acrylate are more preferable, and methyl acrylate is especially preferable.

In the present invention, the glass transition temperature (Tg) of the homopolymer of each monomer can be, for example, a value described in Polymer Handbook Forth Edition (Wiley-Interscience 2003).

((meth)acrylic acid alkyl ester (a-2))

The (meth)acrylic acid alkyl ester (a-2) is a (meth)acrylic acid alkyl ester having a homopolymer having a glass transition temperature (Tg) of less than 0° C. and having an alkyl group having 1 to 12 carbon atoms.

As (meth)acrylic acid alkylester (a-2), the glass transition temperature (Tg) of a homopolymer becomes like this. Preferably it is -80-10 degreeC, More preferably, it is -65-10 degreeC. When Tg is in the said range, it is preferable at the point which has moderate stress relaxation property of the adhesive layer obtained.

As (meth)acrylic acid alkylester (a-2), carbon number of an alkyl group becomes like this. Preferably it is 2-12, More preferably, it is 4-10. Moreover, a linear alkyl group may be sufficient as an alkyl group, and the alkyl group which has a branch may be sufficient.

Specific examples of the (meth)acrylic acid alkyl ester (a-2) include ethyl acrylate (Tg: -24°C), isopropyl acrylate (Tg: -3°C), n-butyl acrylate (Tg: -50°C), Isobutyl acrylate (Tg: -40 ℃), n-hexyl acrylate (Tg: -57 ℃), n-octyl acrylate (Tg: -65 ℃), isooctyl acrylate (Tg: -58 ℃) , 2-ethylhexyl acrylate (Tg: -70 ℃), nonyl acrylate (Tg: -58 ℃), lauryl acrylate (Tg: -3 ℃), n-pentyl methacrylate (Tg: -5 ℃) ), n-hexyl methacrylate (Tg: -5 ℃), n-octyl methacrylate (Tg: -20 ℃), isooctyl methacrylate (Tg: -45 ℃), 2-ethylhexyl methacrylic rate (Tg: -10°C), isodecyl methacrylate (Tg: -41°C), and lauryl methacrylate (Tg: -65°C).

As (meth)acrylic-acid alkylester (a-2), you may use individually by 1 type, and may use 2 or more types. Examples of the (meth)acrylic acid alkyl ester (a-2) include ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, isooctyl methacrylate, 2-ethylhexyl methacrylate, At least one type of monomer selected from isodecyl methacrylate and lauryl methacrylate is preferable, and n-butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, isodecyl methacrylate, and lauryl Methacrylate is more preferable, and n-butyl acrylate and 2-ethylhexyl acrylate are especially preferable.

(carboxyl group-containing monomer (a-3))

A carboxyl group-containing monomer (a-3) is a monomer which has a carboxyl group in a molecule|numerator.

By using the carboxyl group-containing monomer (a-3) as a monomer component used to obtain the (meth)acrylic copolymer (A), it is possible to interact with the amino group of the (meth)acrylic copolymer (B) described later and an adhesive sheet excellent in aging properties can be obtained.

Specific examples of the carboxyl group-containing monomer (a-3) include acrylic acid, methacrylic acid, β-carboxyethyl (meth) acrylate, 5-carboxypentyl (meth) acrylate, succinic acid mono (meth) acryloyloxyethyl ester , ω-carboxypolycaprolactone mono(meth)acrylate, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, and the like.

As a carboxyl group containing monomer (a-3), you may use individually by 1 type and may use 2 or more types.

As the carboxyl group-containing monomer (a-3), it is preferable to use at least one monomer selected from acrylic acid, methacrylic acid, and β-carboxyethyl (meth)acrylate, and at least one selected from acrylic acid and methacrylic acid. It is more preferred to use the monomers of the species. Since these monomers are easy to obtain industrially, they are preferable.

(monomer component of (meth)acrylic copolymer (A))

As described above, the (meth)acrylic copolymer (A) contains 13 to 35% by mass of the (meth)acrylic acid alkyl ester (a-1) and 55 to 80% by mass of the (meth)acrylic acid alkylester (a-2) It is a copolymer of the monomer component containing 3.5-10 mass % of , and a carboxyl group containing monomer (a-3). However, the whole monomer component shall be 100 mass %.

As a monomer component, (a-1) - (a-3) should just be included in the said range, and monomers other than (a-1) - (a-3) may be included. As monomers other than (a-1)-(a-3), 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3- Alkoxyalkyl (meth)acrylates, such as ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, and 4-ethoxybutyl (meth)acrylate: 2-hydroxyethyl (meth)acrylate , 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, containing hydroxyl groups such as 8-hydroxyoctyl (meth) acrylate (meth) ) acrylate: cyclohexyl (meth) acrylate, containing cyclic alkyl groups such as isobornyl (meth) acrylate (meth) acrylate: benzyl (meth) acrylate, phenyl (meth) acrylate, phenoxyethyl (meth) ) Aromatic ring containing (meth)acrylates, such as an acrylate, are mentioned. Moreover, it is preferable not to contain the amino-group containing monomer mentioned later as a monomer component.

When monomers other than (a-1) to (a-3) are used, if the whole monomer component is 100 mass %, monomers other than (a-1) to (a-3) are usually 20 mass % or less , Preferably it is 10 mass % or less.

As a monomer component, 13-35 mass % of (meth)acrylic acid alkyl ester (a-1), 55-80 mass % of (meth)acrylic acid alkyl ester (a-2), and a carboxyl group-containing monomer (a-3) Including 3.5-10 mass %, 15-30 mass % of (meth)acrylic-acid alkylester (a-1), 60-78 mass % of (meth)acrylic-acid alkylester (a-2), and a carboxyl group containing monomer ( It is preferable to contain 4-10 mass % of a-3).

(Manufacturing conditions of (meth)acrylic copolymer (A))

The (meth)acrylic copolymer (A) used for this invention is obtained by copolymerizing the said monomer component.

As a method of copolymerizing, it can manufacture by conventionally well-known polymerization methods, such as a solution polymerization method, a block polymerization method, an emulsion polymerization method, and the suspension polymerization method, for example, Among these, the solution polymerization method is preferable.

Specifically, a polymerization solvent and a monomer component are introduced into the reaction vessel, a polymerization initiator is added under an inert gas atmosphere such as nitrogen gas, and the reaction initiation temperature is usually set to 40 to 100 ° C, preferably 50 to 90 ° C, Usually 50-90 degreeC, Preferably, the (meth)acrylic-type copolymer (A) can be obtained by maintaining the reaction system at the temperature of 60-90 degreeC, and making it react for 3-20 hours.

As a polymerization initiator, an azo type initiator and a peroxide type polymerization initiator are mentioned, for example.

As the azo initiator, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'- Azobis (2-cyclopropylpropionitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylbutyronitrile), 1 ,1'-Azobis(cyclohexane-1-carbonitrile), 2-(carbamoylazo)isobutyronitrile, 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile , 2,2'-azobis(2-amidinopropane)dihydrochloride, 2,2'-azobis(N,N'-dimethylisobutylamidine), 2,2'-azobis[2 -Methyl-N-(2-hydroxyethyl)-propionamide], 2,2'-azobis(isobutylamide)dihydrate, 4,4'-azobis(4-cyanopentanoic acid), 2, 2'-azobis(2-cyanopropanol), dimethyl-2,2'-azobis(2-methylpropionate), 2,2'-azobis(2-methyl-N-(2-hydride) Azo compounds, such as oxyethyl) propionamide), are mentioned.

Examples of the peroxide polymerization initiator include t-butyl hydroperoxide, cumene hydroxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, caproyl peroxide, di-i-propyl peroxydicarbonate, and di-2 -Ethylhexyl peroxydicarbonate, t-butylperoxypivalate, 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane, 2,2-bis(4,4-di -t-amylperoxycyclohexyl)propane, 2,2-bis(4,4-di-t-octylperoxycyclohexyl)propane, 2,2-bis(4,4-di-α-cu Milperoxycyclohexyl)propane, 2,2-bis(4,4-di-t-butylperoxycyclohexyl)butane, 2,2-bis(4,4-di-t-octylperoxycyclohexyl) ) butane.

A polymerization initiator may be used individually by 1 type, and may use 2 or more types. Moreover, adding a polymerization initiator multiple times during polymerization is also not restrict|limited.

A polymerization initiator is 0.001-5 mass parts normally with respect to 100 mass parts of monomer components which form the (meth)acrylic-type copolymer (A), Preferably it is used in the quantity within the range of 0.005-3 mass parts. Moreover, you may further add a polymerization initiator, a chain transfer agent, a polymerizable monomer, and a polymerization solvent suitably during the said polymerization reaction.

As a polymerization solvent used for solution polymerization, For example, aromatic hydrocarbons, such as benzene, toluene, and xylene; aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, and n-octane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane; ethers such as diethyl ether, diisopropyl ether, 1,2-dimethoxyethane, dibutyl ether, tetrahydrofuran, dioxane, anisole, phenylethyl ether, and diphenyl ether; halogenated hydrocarbons such as chloroform, carbon tetrachloride, 1,2-dichloroethane and chlorobenzene; esters such as ethyl acetate, propyl acetate, butyl acetate, and methyl propionate; ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, and cyclohexanone; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; nitriles such as acetonitrile and benzonitrile; Sulfoxides, such as dimethyl sulfoxide and a sulfolane, etc. are mentioned.

A polymerization solvent may be used individually by 1 type, and may use 2 or more types.

(Physical properties of (meth)acrylic copolymer (A))

The (meth)acrylic copolymer (A) has a weight average molecular weight (Mw) measured by, for example, a gel permeation chromatography method (GPC method) is usually 400,000 or more in terms of polystyrene, preferably 500,000 to It is 1.5 million, More preferably, it is 600,000-1.3 million, More preferably, it is 700,000-1.2 million. When Mw is more than the said lower limit, it is preferable at the point excellent in the durability of the adhesive layer formed from the adhesive composition, and cohesion force. If Mw is below the said upper limit, it is preferable at the point with favorable coatability of an adhesive composition.

The (meth)acrylic copolymer (A) has a molecular weight distribution (weight average molecular weight (Mw)/number average molecular weight (Mn)) measured by the GPC method is usually 1.5 to 20, preferably 2 to 18, more preferably It is 2-15. When Mw/Mn is more than the said lower limit, it is preferable from the point of adhesive expression to the to-be-adhered body etc. of the adhesive expression in the adhesive layer in an adhesive sheet, and a base material, or the like. If Mw/Mn is below the said upper limit, it is excellent in heat resistance, and it is preferable at the point of durability maintenance.

As for the (meth)acrylic copolymer (A), the glass transition temperature (Tg) calculated|required from Fox's formula is -70-0 degreeC normally, Preferably it is -70-20 degreeC. If it is such an aspect, the adhesive which has the outstanding adhesive strength can be obtained.

The amount of polymerization initiator (residual initiator amount) measured by the method (gas chromatograph mass spectrometer (GCMS)) described in Examples to be described later is usually 800 ppm or less with respect to 100 wt% of the (meth)acrylic copolymer (A), preferably Preferably it is 750 ppm or less, More preferably, it is 700 ppm or less. In addition, in the present invention, ppm means ppm based on weight, that is, parts per million weight (ppmw). In addition, since it is preferable that the amount of the remaining initiator is smaller, the lower limit is not particularly limited, but the lower limit of the amount of the remaining initiator is, for example, 50 ppm or more with respect to 100% by weight of the (meth)acrylic copolymer (A).

The amount of the polymerization initiator contained in the (meth)acrylic copolymer (A) can be increased or decreased by, for example, adjusting the production conditions of the (meth)acrylic copolymer (A). For example, it tends to decrease by lengthening the reaction time at the time of manufacturing a (meth)acrylic-type copolymer (A), raising the reaction temperature, and using an appropriate amount of an initiator. Conversely, it tends to increase by shortening the reaction time, lowering the reaction temperature, and using an excessive amount of the initiator.

By making the amount of residual initiator of (meth)acrylic-type copolymer (A) into the said range, the amount of residual initiator of the adhesive composition of this invention can be made into 800 ppm or less. According to the studies of the present inventors, by making the amount of the residual initiator of the pressure-sensitive adhesive composition 800 ppm or less, the side reaction caused conventionally by factors such as the pressure-sensitive adhesive sheet stored in a high-temperature environment or UV irradiation can be suppressed, and the pressure-sensitive adhesive layer It was discovered that it could prevent it from becoming a citron shell shape. For this reason, the adhesive sheet which is excellent in weather resistance, foaming resistance, and rework property and does not raise|generate a zipping phenomenon can be obtained by controlling the amount of residual initiator of an adhesive composition.

((meth)acrylic copolymer (B))

The pressure-sensitive adhesive composition of the present invention contains a (meth)acrylic copolymer (B). The (meth)acrylic copolymer (B) is a copolymer of a monomer component containing an alkyl methacrylate ester (b-1) having 1 to 20 carbon atoms in the alkyl group and an amino group-containing monomer (b-2).

(Methacrylic acid alkyl ester (b-1))

The methacrylic acid alkyl ester (b-1) is an alkyl methacrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group.

As alkyl methacrylic acid ester (b-1), carbon number of an alkyl group becomes like this. Preferably it is 1-18, More preferably, it is 1-12, More preferably, it is 1-8.

Examples of the alkyl methacrylate ester (b-1) include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, nonyl methacrylate, I and sononyl methacrylate, decyl methacrylate, isodecyl methacrylate, undeca methacrylate, lauryl methacrylate, stearyl methacrylate, and isostearyl methacrylate. These may be used individually by 1 type, and may use 2 or more types.

As the alkyl methacrylate ester (b-1), methyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, isodecyl methacrylate, lauryl methacrylate, iso At least one type of monomer selected from stearyl methacrylate is preferable, and at least one type of monomer selected from methyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, and 2-ethylhexyl methacrylate is more preferable.

(Amino group-containing monomer (b-2))

The amino group-containing monomer (b-2) is a monomer having an amino group in the molecule. The amino group-containing monomer (b-2) may be a monomer having one amino group in one molecule, or a monomer having two or more amino groups.

As the amino group-containing monomer (b-2), for example, N,N-dialkylaminoalkyl ( meth) acrylate.

As an amino-group containing monomer (b-2), you may use individually by 1 type, and may use 2 or more types.

The (meth)acrylic copolymer (B) in which the amino group-containing monomer (b-2) is copolymerized is preferable because it is excellent in compatibility with the (meth)acrylic copolymer (A).

(monomer component of (meth)acrylic copolymer (B))

As described above, the (meth)acrylic copolymer (B) is a copolymer of a monomer component containing an alkyl methacrylic acid ester (b-1) and an amino group-containing monomer (b-2).

As a monomer component, it is preferable to make 80-98 mass % of methacrylic acid alkylester (b-1), and it is 2-20 mass % of an amino-group containing monomer (b-2), and alkyl methacrylic acid ester (b-1) It is more preferable to make into 85-96 mass % and an amino-group containing monomer (b-2) into 4-10 mass %. However, the whole monomer component shall be 100 mass %.

As a monomer component, (b-1) and (b-2) may be included, and monomers other than (b-1) and (b-2) may be included. As monomers other than (b-1) and (b-2), methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate , pentyl acrylate, hexyl acrylate, heptyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, nonyl acrylate, isononyl acrylate, decyl acrylate, isodecyl acrylate , acrylic acid alkyl esters such as undeca acrylate, lauryl acrylate, stearyl acrylate, isostearyl acrylate: 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3 - Alkoxyalkyl (meth)acrylics, such as methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, and 4-ethoxybutyl (meth)acrylate Rate: 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxy Hydroxyl group-containing (meth)acrylates such as octyl (meth)acrylate: Cyclic alkyl group-containing (meth)acrylates such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate: benzyl (meth)acrylate; Aromatic ring containing (meth)acrylates, such as phenyl (meth)acrylate and phenoxyethyl (meth)acrylate, are mentioned. Moreover, it is preferable not to contain the above-mentioned carboxyl group containing monomer as a monomer component.

When monomers other than (b-1) and (b-2) are used, if the whole monomer component is 100 mass %, monomers other than (b-1) and (b-2) are usually 15 mass % or less , Preferably it is 10 mass % or less.

(Manufacturing conditions of (meth)acrylic copolymer (B))

The (meth)acrylic copolymer (B) used for this invention is obtained by copolymerizing the said monomer component.

As a method of copolymerizing, it can manufacture by conventionally well-known polymerization methods, such as a solution polymerization method, a block polymerization method, an emulsion polymerization method, and the suspension polymerization method, for example, Among these, the solution polymerization method is preferable.

Specifically, a polymerization solvent and a monomer component are introduced into the reaction vessel, a polymerization initiator is added under an inert gas atmosphere such as nitrogen gas, and the reaction initiation temperature is usually set to 40 to 100 ° C, preferably 50 to 90 ° C, Usually, the (meth)acrylic copolymer (B) can be obtained by maintaining the reaction system at a temperature of 50 to 90°C, preferably 60 to 90°C, and reacting it for 4 to 20 hours.

As a polymerization initiator, the thing described in the item of the said (manufacturing conditions of (meth)acrylic-type copolymer (A)) can be used suitably. In addition, the polymerization initiator used when manufacturing the (meth)acrylic-type copolymer (A) and the polymerization initiator used when manufacturing the (meth)acrylic-type copolymer (B) may be the same or different may be used.

A polymerization initiator is 0.001-5 mass parts normally with respect to 100 mass parts of monomer components which form the (meth)acrylic-type copolymer (B), Preferably it is used in the amount within the range of 0.005-3 mass parts. Moreover, you may further add a polymerization initiator, a chain transfer agent, a polymerizable monomer, and a polymerization solvent suitably during the said polymerization reaction.

As a polymerization solvent used for solution polymerization, the thing described in the item of the said (manufacturing conditions of (meth)acrylic-type copolymer (A)) can be used suitably. Moreover, the polymerization solvent used when manufacturing a (meth)acrylic-type copolymer (A) and the polymerization solvent used when manufacturing a (meth)acrylic-type copolymer (B) may be the same, and may use a different thing.

(Physical properties of (meth)acrylic copolymer (B))

The (meth)acrylic copolymer (B) has, for example, a weight average molecular weight (Mw) measured by a gel permeation chromatography method (GPC method) is usually 1000 to 50000 in terms of polystyrene, preferably 2000 to 30000 and more preferably 3000 to 10000. In the said range, it is preferable at the point with good compatibility with the (meth)acrylic-type copolymer (A) mentioned above.

The (meth)acrylic copolymer (B) has a molecular weight distribution (weight average molecular weight (Mw)/number average molecular weight (Mn)) measured by GPC method is usually 1.1 to 10, preferably 1.2 to 8, more preferably 1.2-7, More preferably, it is 1.3-6.5.

As for the (meth)acrylic copolymer (B), the glass transition temperature (Tg) calculated|required from Fox's formula is 80 degreeC or more normally, Preferably it is 85-120 degreeC, More preferably, it is 90-110 degreeC. If it is such an aspect, the adhesive excellent in durability can be obtained.

The amount of polymerization initiator (residual initiator amount) measured by the method (gas chromatograph mass spectrometer (GCMS)) described in Examples to be described later is usually 200 ppm or less with respect to 100 wt% of the (meth)acrylic copolymer (B), preferably Preferably it is 150 ppm or less, More preferably, it is 100 ppm or less. In addition, since it is preferable that the amount of the remaining initiator is smaller, the lower limit is not particularly limited, but the lower limit of the amount of the remaining initiator is, for example, 10 ppm or more with respect to 100% by weight of the (meth)acrylic copolymer (B).

The amount of the polymerization initiator contained in the (meth)acrylic copolymer (B) can be increased or decreased by, for example, adjusting the production conditions of the (meth)acrylic copolymer (B). For example, it tends to decrease by lengthening the reaction time at the time of manufacturing a (meth)acrylic-type copolymer (B), raising the reaction temperature, and using an appropriate amount of an initiator. Conversely, it tends to increase by shortening the reaction time, lowering the reaction temperature, and using an excessive amount of the initiator.

By making the amount of residual initiator of (meth)acrylic copolymer (B) into the said range, the amount of residual initiator of the adhesive composition of this invention can be made into 800 ppm or less. According to the studies of the present inventors, by making the amount of residual initiator in the pressure-sensitive adhesive composition 800 ppm or less, side reactions can be suppressed due to factors such as the pressure-sensitive adhesive sheet being stored in a high-temperature environment or UV irradiation, and the pressure-sensitive adhesive layer has a citron shell shape found out what could be done to prevent it from happening. For this reason, by controlling the amount of residual initiator of an adhesive composition, it is excellent in weather resistance, foaming resistance, and rework property, and the adhesive sheet which does not raise|generate a zipping phenomenon can be obtained.

(crosslinking agent (C))

The pressure-sensitive adhesive composition of the present invention contains a crosslinking agent (C).

Although there is no limitation in particular as a crosslinking agent (C), An epoxy type crosslinking agent, an isocyanate type crosslinking agent, a metal chelate compound, etc. can be used. As a crosslinking agent, you may use individually by 1 type, and may use 2 or more types.

As an epoxy-based crosslinking agent, (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-m-xylylenediamine, N, N,N',N'-tetraglycidylaminophenylmethane, triglycidyl isocyanate, mN,N-diglycidylaminophenylglycidyl ether, N,N-diglycidyl Toluidine, N,N-diglycidylaniline, pentaerythritol polyglycidyl ether, 1,6-hexanediol diglycidyl ether, etc. are mentioned.

Examples of the isocyanate-based crosslinking agent include tolylene diisocyanate, chlorphenylene diisocyanato, hexamethylene diisocyanato, tetramethylene diisocyanato, isophorone diisocyanate, and xylylene. Isocyanate monomers such as diisocyanate, diphenylmethane diisocyanate, and hydrogenated diphenylmethane diisocyanate, and addition reaction of trimethylolpropane to these isocyanate monomers urethane obtained by addition reaction of polyether polyol, polyester polyol, acrylic polyol, polybutadiene polyol, polyisoprene polyol, etc. A prepolymer type isocyanate etc. are mentioned.

Examples of the metal chelate compound include compounds in which an alkoxide, acetylacetone, ethyl acetoacetate, etc. are coordinated with a polyvalent metal such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium. . Specific examples thereof include aluminum isopropylate, aluminum secondary rebutylate, aluminum ethyl acetoacetate diisopropylate, aluminum trisethylacetoacetate, and aluminum trisacetylacetonate.

As a crosslinking agent, an epoxy-type crosslinking agent is preferable from a viewpoint of being excellent in heat resistance.

The pressure-sensitive adhesive composition of the present invention can form a three-dimensional crosslinked structure by reacting the crosslinking agent, and it is possible to express high adhesive force and cohesive force.

(Composition of adhesive composition)

The pressure-sensitive adhesive composition of the present invention contains 1 to 40 parts by mass of the (meth)acrylic copolymer (B) and 0.01 to 5 parts by mass of the crosslinking agent (C) with respect to 100 parts by mass of the (meth)acrylic copolymer (A), preferably 3 to 35 parts by mass of the (meth)acrylic copolymer (B), 0.03 to 3 parts by mass of the crosslinking agent (C), more preferably 5 to 30 parts by mass of the (meth)acrylic copolymer (B) , a crosslinking agent (C) is contained in an amount of 0.05 to 2.5 parts by mass. When the compounding quantity of each component exists in the said range, since the adhesive sheet which is excellent in rework property and does not raise|generate a zipping phenomenon can be obtained using the adhesive composition of this invention, it is preferable.

The pressure-sensitive adhesive composition of the present invention further includes various additives such as tackifying resin, antistatic agent, silane coupling agent, antioxidant, UV absorber, plasticizer, fine particles, and pigment within the range that does not impair the physical properties of the pressure-sensitive adhesive composition of the present invention. you may be doing When the adhesive composition of this invention contains components other than said (A)-(C), it is 0.03-30 mass % normally in components other than (A)-(C) in 100 mass % of solid content of an adhesive composition, Preferably Preferably it is 0.05-25 mass %, More preferably, it contains 0.08-20 mass %.

The adhesive composition of this invention may contain the organic solvent in the range which does not impair the effect of this invention other than the said component.

As an organic solvent, the polymerization solvent described in description of the manufacturing method of a (meth)acrylic-type copolymer (A) is mentioned, for example. The pressure-sensitive adhesive composition of the present invention includes, for example, a polymer solution containing a (meth)acrylic copolymer (A) and a polymerization solvent, a polymer solution containing a (meth)acrylic copolymer (B) and a polymerization solvent, and a crosslinking agent (C) ) can be prepared by mixing. The adhesive composition of this invention WHEREIN: Content of an organic solvent is 0-90 mass % normally, Preferably it is 10-80 mass %.

(Method for producing pressure-sensitive adhesive composition)

The adhesive composition of this invention is obtained by mixing each component (for example, above-mentioned (A)-(C)) contained in an adhesive composition by a well-known method using a stirring apparatus etc.

That is, the adhesive composition of this invention is obtained by mixing and stirring each component collectively or sequentially. The stirring time is not particularly limited, but may be about 10 to 120 minutes at room temperature in terms of workability and productivity.

(Physical properties of the adhesive composition)

In the pressure-sensitive adhesive composition of the present invention, the polymerization initiator amount (residual initiator amount) contained in 100% by weight of the solid content of the pressure-sensitive adhesive composition is 800 ppm or less. The amount of the remaining initiator is the amount of the polymerization initiator contained in the pressure-sensitive adhesive composition, and is expressed as the amount when the solid content of the pressure-sensitive adhesive composition is 100% by weight. The polymerization initiator contained in the pressure-sensitive adhesive composition of the present invention is derived from a polymerization initiator used when polymerizing the (meth)acrylic copolymer (A) and the (meth)acrylic copolymer (B), and does not react during the polymerization. One polymerization initiator is included in the pressure-sensitive adhesive composition, and the amount is the amount of the remaining initiator. In addition, when the pressure-sensitive adhesive composition of the present invention contains a polymer other than the (meth)acrylic copolymer (A) and the (meth)acrylic copolymer (B), this (meth)acrylic copolymer (A) and (meth) When the polymerization initiator used when manufacturing polymers other than the acrylic copolymer (B) remains in the pressure-sensitive adhesive composition, the amount of the remaining polymerization initiator is also included in the amount of the remaining initiator of the pressure-sensitive adhesive composition.

The amount of the residual initiator may be obtained by removing the organic solvent from the pressure-sensitive adhesive composition to obtain a solid content, and the amount of the polymerization initiator contained in the solid content may be measured by a gas chromatograph mass spectrometer (GCMS), or the polymerization initiator contained in the pressure-sensitive adhesive composition Quantity is measured by GCMS, and you may compute by calculating|requiring the ratio of the solid content in an adhesive composition simultaneously or separately, the amount of residual initiator in each component which comprises an adhesive composition is measured, The amount of residual initiator in each component, and usage-amount of each component You may calculate from (ratio).

The amount of polymerization initiator contained in 100 weight% of solid content of the adhesive composition of this invention is 800 ppm or less, More preferably, it is 700 ppm or less, Especially preferably, it is 650 ppm or less. Within the above range, it is preferable because the layer (adhesive layer) formed from the pressure-sensitive adhesive composition of the present invention is suppressed from forming a citron shell shape when irradiated with ultraviolet rays. As a minimum of the amount of residual initiators of the adhesive composition of this invention, it is so preferable that it is low, There is no restriction|limiting in particular, Usually, it is 30 ppm or more.

[Adhesive layer]

An adhesive layer is produced from the adhesive composition mentioned above. For example, by advancing the crosslinking reaction in the adhesive composition mentioned above, the said adhesive layer is obtained by specifically bridge|crosslinking a (meth)acrylic-type copolymer (A) with a crosslinking agent (C).

The formation conditions of an adhesive layer are as follows, for example. The pressure-sensitive adhesive composition of the present invention is applied on the release treatment surface of the substrate or release sheet, and although it may differ depending on the type of solvent, it is usually 50 to 150° C., preferably 60 to 100° C., usually 1 to 10 minutes, preferably Dry for 2-7 minutes to remove the solvent and form a coating film. The film thickness of a dry coating film is 5-125 micrometers normally, Preferably it is 10-100 micrometers.

It is preferable to form an adhesive layer on condition of the following. After apply|coating the adhesive composition of this invention on the peeling process surface of a base material or a peeling sheet, and affixing a peeling sheet on the coating film formed under the said conditions, it is 3 days or more normally, Preferably it is 7-10 days, Usually 5-60. ℃, preferably 15 to 40 ℃, usually 5 to 70% RH, preferably cured in an environment of 5 to 50% RH. When crosslinking is performed under the aging conditions as described above, it is possible to efficiently form a crosslinked product (network polymer).

As a method for applying the pressure-sensitive adhesive composition, a known method, for example, a spin coat method, a knife coat method, a roll coat method, a bar coat method, a blade coat method, a die coat method, or a gravure coat method, is applied and dried to a predetermined thickness. method can be used.

[adhesive sheet]

The adhesive sheet of this invention has the adhesive layer produced from the adhesive composition of this invention.

The pressure-sensitive adhesive sheet of the present invention does not have a citron shell shape, has excellent weather resistance, foaming resistance, and reworkability, and does not cause a zipping phenomenon, so that it can be suitably used for applications requiring these properties.

The pressure-sensitive adhesive sheet of the present invention may be a pressure-sensitive adhesive sheet composed of only the pressure-sensitive adhesive layer produced from the pressure-sensitive adhesive composition, or may be a pressure-sensitive adhesive sheet that is a laminate having a base layer and an pressure-sensitive adhesive layer.

What is necessary is just to set suitably according to the use of an adhesive sheet etc. as thickness of an adhesive layer, Although there is no restriction|limiting in particular, Usually, it is 5-125 micrometers, Preferably it is 10-100 micrometers.

When the pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet comprising only a pressure-sensitive adhesive layer prepared from the pressure-sensitive adhesive composition, for example, the pressure-sensitive adhesive composition is applied on a peel-treated substrate, and, if necessary, additionally peeled on the coated surface. It is obtained by forming an adhesive layer by arrange|positioning a base material. The pressure-sensitive adhesive sheet comprising only the pressure-sensitive adhesive layer is stored and moved together with the peel-treated base material during storage and movement, but the peel-treated base material peels off during use and is used as a pressure-sensitive adhesive sheet comprising only the pressure-sensitive adhesive layer.

When the pressure-sensitive adhesive sheet of the present invention is a laminate having a base material layer and an pressure-sensitive adhesive layer, for example, the pressure-sensitive adhesive composition is applied on the base material, and if necessary, the base material is further disposed on the coated surface by disposing the base material to be peeled off. It is obtained by forming an adhesive layer on it. When this pressure-sensitive adhesive layer is used, the base material subjected to the peeling treatment is peeled off, and is used as a pressure-sensitive adhesive sheet composed of a base material layer and an pressure-sensitive adhesive layer.

As another example, an adhesive sheet may be obtained by providing an adhesive layer on both sides of a base material layer, and also arrange|positioning the base material by which the peeling process was carried out on the both sides.

Although there is no limitation in particular as said base material, Plastic, glass, a woven fabric, a nonwoven fabric, paper, etc. are mentioned. As the plastic, a transparent plastic is preferable, and as the transparent plastic, polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polypropylene (PP), acrylonitrile-butadiene-styrene A copolymer (ABS), polyamide (nylon), etc. are mentioned.

Although there is no restriction|limiting in particular as a use of the adhesive sheet of this invention, It can use as an adhesive sheet for protection and scattering prevention of plastics and glass.

(Example)

Next, the present invention will be described in more detail by showing examples, but the present invention is not limited thereto.

The physical property of the copolymer obtained by the following manufacture example, and the amount of the residual initiator of an adhesive composition were measured by the following method.

(Mw, Mw/Mn)

The weight average molecular weight and molecular weight distribution of the copolymer obtained in the following Production Examples were measured by a gel permeation chromatography method (GPC method) under the following conditions. ·Measuring device: HLC-8320GPC (made by tossing agent) ·GPC column configuration: the following four columns (all made by tossing) (1) TSKgel HxL-H (guard column) (2) TSKgel GMHxL (3) TSKgel GMHxL (4) TSKgel G2500HxL Flow rate: 1.0mL/min Column temperature: 40°C Sample concentration: 1.5% (w/v) (diluted with tetrahydrofuran) Mobile phase solvent: tetrahydrofuran standard polystyrene equivalent

(Residual initiator amount of copolymer and pressure-sensitive adhesive composition)

The quantity of the residual initiator contained in the copolymer obtained by the following manufacture example, each Example, and the adhesive composition obtained by the comparative example was measured by the gas chromatograph mass spectrometer (GCMS method) under the following conditions. ·Pretreatment

A polymer solution or pressure-sensitive adhesive composition was collected, and the polymer solution or pressure-sensitive adhesive composition was dissolved in acetone. While mixing the sample dissolved in the acetone, n-hexane was added dropwise and mixed well, and then left still for 1 hour. Then, the supernatant liquid was collect|recovered, filtration was performed, and the filtrate was used as the sample liquid. About the obtained sample liquid, the amount of residual initiator was measured using the gas chromatograph mass spectrometer (GCMS method). About the obtained measured value, the value converted into 100 mass % of solid content is shown in Table 1 and Table 2. Measuring device: Agilent: 6890N/5973inert (manufactured by Agilent Technologies) Column: HP-5ms 30m×0.25mm, 0.25μm (manufactured by Agilent Technologies) Oven: 100°C×15 minutes, inlet: 110°C Detector: MS (ion source: 230℃, MS quadrupole: 150℃) Detection method: SIM Split: 30:1

The temperature of the oven and the temperature of the inlet can be set according to the type of polymerization initiator (half-life temperature of the polymerization initiator), and the conditions are suitable for 2,2'-azobisisobutyronitrile used in Preparation Example.

[Production Example A-1]

75 parts by mass of n-butyl acrylate (BA), 18 parts by mass of methyl acrylate (MA), 7 mass parts of acrylic acid (AA) was thrown in, and 150 mass parts of ethyl acetate was thrown in as a solvent.

Then, 0.1 mass part of 2,2'- azobisisobutyronitrile (AIBN) was injected|thrown-in as a polymerization initiator, stirring in nitrogen gas atmosphere, and reaction was performed at 70 degreeC for 7 hours. After completion of the reaction, the reaction solution was diluted with ethyl acetate to prepare a polymer solution having a solid content concentration of 20% by mass containing copolymer A-1.

Mw of the copolymer A-1 was 800,000, Mw/Mn was 3.1, and the amount of residual initiator was 660 ppm.

[Production Example A-2]

In the same manner as in Production Example A-1, except that the amount of n-butyl acrylate (BA) was changed from 75 parts by mass to 77.5 parts by mass, and the amount of acrylic acid (AA) was changed from 7 parts by mass to 4.5 parts by mass, the copolymer A polymer solution having a solid content concentration of 20% by mass containing A-2 was prepared.

Mw of copolymer A-2 was 800,000, Mw/Mn was 3.3, and the amount of residual initiator was 670 ppm.

[Production Example A-3]

The amount of n-butyl acrylate (BA) was changed from 75 parts by mass to 63 parts by mass, and the amount of methyl acrylate (MA) was changed from 18 parts by mass to 30 parts by mass, as in Production Example A-1, A polymer solution having a solid content concentration of 20% by mass containing copolymer A-3 was prepared.

Mw of copolymer A-3 was 750,000, Mw/Mn was 3.4, and the amount of residual initiator was 680 ppm.

[Production Example A-4]

20 mass % of solid content concentration containing copolymer A-4 in the same manner as in Production Example A-1 except that the amount of the polymerization initiator was changed from 0.1 parts by mass to 0.2 parts by mass and the reaction time was changed from 7 hours to 4 hours. of the polymer solution was prepared.

Mw of copolymer A-4 was 750,000, Mw/Mn was 3.5, and the amount of residual initiator was 1200 ppm.

[Production Example A-5]

In the same manner as in Production Example A-1, except that the amount of n-butyl acrylate (BA) was changed from 75 parts by mass to 79 parts by mass, and the amount of acrylic acid (AA) was changed from 7 parts by mass to 3 parts by mass, the copolymer A polymer solution having a solid content concentration of 20% by mass containing A-5 was prepared.

Mw of copolymer A-5 was 800,000, Mw/Mn was 3.4, and the amount of residual initiator was 680 ppm.

[Production Example A-6]

The same procedure as in Production Example A-1 was performed except that the amount of n-butyl acrylate (BA) was changed from 75 parts by mass to 70 parts by mass, and the amount of acrylic acid (AA) was changed from 7 parts by mass to 12 parts by mass, and the copolymer A polymer solution having a solid content concentration of 20% by mass containing A-6 was prepared.

Mw of copolymer A-6 was 750,000, Mw/Mn was 3.0, and the amount of residual initiator was 630 ppm.

[Production Example A-7]

The amount of n-butyl acrylate (BA) was changed from 75 parts by mass to 83 parts by mass, and the amount of methyl acrylate (MA) was changed from 18 parts by mass to 10 parts by mass, as in Production Example A-1, A polymer solution having a solid content concentration of 20% by mass containing copolymer A-7 was prepared.

Mw of the copolymer A-7 was 800,000, Mw/Mn was 3.1, and the amount of residual initiator was 640 ppm.

[Production Example A-8]

The amount of n-butyl acrylate (BA) was changed from 75 parts by mass to 53 parts by mass, and the amount of methyl acrylate (MA) was changed from 18 parts by mass to 40 parts by mass, as in Production Example A-1, A polymer solution having a solid content concentration of 20% by mass containing copolymer A-8 was prepared.

Mw of the copolymer A-8 was 800,000, Mw/Mn was 3.4, and the amount of residual initiator was 730 ppm.

[Production Example B-1]

95 parts by mass of methyl methacrylate (MMA) as a polymerizable monomer and 5 parts by mass of dimethylaminoethyl methacrylate (DM) as a polymerizable monomer in a 2-liter four-neck flask equipped with a stirrer, a thermometer, a nitrogen gas introduction tube and a cooling tube Parts were thrown in, and 100 mass parts of toluene was thrown in as a solvent.

Subsequently, while stirring in a nitrogen gas atmosphere, 3 parts by mass of AIBN was added as a polymerization initiator, and the reaction was performed at 80°C for 10 hours to prepare a solution having a solid content concentration of 50% by mass containing copolymer B-1.

Tg of copolymer B-1 was 99 degreeC, Mw was 0.5 million, Mw/Mn was 1.5, and the amount of residual initiator was 50 ppm.

[Production Example B-2]

Except having changed 95 mass parts of methyl methacrylate (MMA) into 95 mass parts of t-butyl methacrylate (t-BMA), it carried out similarly to manufacture example B-1, and solid content concentration 50 mass % containing copolymer B-2 of the polymer solution was prepared.

Tg of copolymer B-2 was 101 degreeC, Mw was 0.5 million, Mw/Mn was 1.8, and the amount of residual initiator was 60 ppm.

[Production Example B-3]

Production example B-1, except that the amount of methyl methacrylate (MMA) was changed from 95 parts by mass to 100 parts by mass, and the amount of dimethylaminoethyl methacrylate (DM) was changed from 5 parts by mass to 0 parts by mass. It carried out similarly, and the polymer solution of 50 mass % of solid content concentration containing copolymer B-3 was prepared.

Tg of copolymer B-3 was 105 degreeC, Mw was 0.5 million, Mw/Mn was 1.5, and the amount of residual initiator was 50 ppm.

Table 1 summarizes the polymers obtained in Production Examples.

[Example 1]

Polymer solution (solid content concentration: 20 mass%) obtained in Production Example A-1, solution (solid content concentration: 50 mass%) obtained in Production Example B-1, and epoxy-based crosslinking agent E-5XM (manufactured by Soken Chemicals: Solid content concentration: 5 mass %) was mixed in such an amount that the copolymer A-1 was 100 parts by mass, the copolymer B-1 was 15 parts by mass, and E-5XM was 0.075 parts by mass to obtain an adhesive composition.

[Examples 2, 4-6, Comparative Examples 1-8, Reference Example]

Except having changed the compounding composition of an adhesive composition as described in Table 2, it carried out similarly to Example 1, and prepared the adhesive composition.

The following methods measured and evaluated the adhesive composition obtained by the Example, the comparative example, and the reference example.

(Preparation of adhesive sheet)

The adhesive composition was coated on the polyethylene terephthalate (PET) film by which the peeling process was carried out so that the thickness after drying might be set to 20 micrometers, and it was made to dry at 80 degreeC for 2 minutes, and the adhesive layer was formed.

A PET film with a thickness of 38 μm subjected to peeling is placed on the side opposite to the side in contact with the PET film of the pressure-sensitive adhesive layer, and aged for 7 days at 23° C., 50% RH environment, and the pressure-sensitive adhesive layer (thickness 20 μm) on the PET film An adhesive sheet having a

(Evaluation of reworkability, zipping phenomenon)

The PET film with a thickness of 38 µm subjected to peeling treatment was peeled off from the pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive layer was transferred to a PET film having a thickness of 100 µm (diafoil T680E100; manufactured by Mitsubishi Corporation), and then cut to a width of 25 mm to prepare a test piece. The PET film by which the peeling process was peeled off from the obtained test piece was affixed to the glass plate, and the exposed adhesive layer was affixed and it crimped|bonded by 2 kg roller 3 reciprocation. After crimping, after leaving it for 24 hours in an environment of 23°C and 50% RH, pull the end of the test piece at an angle of 90° with respect to the glass plate at a speed of 300 mm/min to determine the reworkability and zipping phenomenon, respectively, according to the following standards. evaluated as

・Reworkability

◎: No glue remains on the glass plate after peeling the adhesive sheet

○: No glue remained on the glass plate after peeling the adhesive sheet, but the sticking marks were seen.

(triangle|delta): Paste remains in less than 20% of affixing area on the glass plate after adhesive sheet peeling.

x: 20% or more of paste remains on the glass plate after adhesive sheet peeling

· zip

○: There is no sound when the adhesive sheet is peeled from the glass plate

×: A sound is produced when the adhesive sheet is peeled from the glass plate

(Evaluation of foam resistance)

Peel off the PET film with a thickness of 38 μm subjected to peeling treatment from the pressure-sensitive adhesive sheet, and transfer the pressure-sensitive adhesive layer to a PET film having a thickness of 100 μm (diafoil T680E100; manufactured by Mitsubishi Corporation), and then cut to a width of 50 mm × 50 mm to prepare a test piece. The PET film by which the peeling process was peeled off from the obtained test piece was peeled, the exposed adhesive layer was affixed to a polycarbonate board, and the presence or absence of a bubble was visually judged after leaving it to stand in 80 degreeC environment for 150 hours.

◎: No bubbles

○: There are some bubbles, but there is no problem in practical use

×: Bubbles exist over a wide area

(Evaluation of UV resistance)

^{The adhesive sheet was irradiated with ultraviolet rays (60 W/m 2} ) for 168 hours using a UV lamp (strong energy xenon weather meter type: SC750W manufactured by Sugashi Kenki).

After the irradiation, the pressure-sensitive adhesive sheet was observed to determine whether or not there were irregularities on the surface of the pressure-sensitive adhesive layer, that is, whether or not it had a citron shell shape.

○: No citron shell shape

×: citron shell shape

It was judged that the thing which did not have a citron shell shape was excellent also in weather resistance.

Examples, comparative examples, and reference examples are summarized in Table 2.

Claims (3)

13 to 35 mass % of (meth)acrylic acid alkyl ester having a glass transition temperature (Tg) of the homopolymer of 0 to 120° C. and having 1 to 12 carbon atoms in the alkyl group;
The glass transition temperature (Tg) of the homopolymer is -80 ° C. or more and less than 0 ° C., and 55 to 80 mass % of (meth) acrylic acid alkyl ester having 1 to 12 carbon atoms in the alkyl group;
and a (meth)acrylic copolymer (A) having a weight average molecular weight (Mw) of 800,000 to 1,500,000 as a copolymer of a monomer component containing 4 to 10% by mass of a carboxyl group-containing monomer;
A (meth)acrylic copolymer (B), which is a copolymer of an alkyl methacrylic acid ester having 1 to 20 carbon atoms in the alkyl group, and a monomer component containing an amino group-containing monomer;
It is a pressure-sensitive adhesive composition comprising a crosslinking agent (C),
The pressure-sensitive adhesive composition contains 1 to 40 parts by mass of the (meth)acrylic copolymer (B) and 0.01 to 5 parts by mass of the crosslinking agent (C) with respect to 100 parts by mass of the (meth)acrylic copolymer (A),
The amount of the polymerization initiator contained in 100% by weight of the solid content of the pressure-sensitive adhesive composition is 800ppm or less pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition according to claim 1, wherein the (meth)acrylic copolymer (B) has a weight average molecular weight of 1,000 to 50,000 and a glass transition temperature of 80 to 120°C. The adhesive sheet which has an adhesive layer produced from the adhesive composition of Claim 1 or 2.