KR102540270B1 - Method for producing pressure-sensitive adhesive composition, pressure-sensitive adhesive sheet, and ethylenically unsaturated group-containing acrylic resin - Google Patents

Abstract

[R¹은 에틸렌성 불포화기를 함유하는 치환기이며,
R²는 C, O, N 및 S로부터 선택되는 적어도 1종을 포함하는 유기기
(단, 카르바메이트기는 제외함)이며, X는 O 또는 NH이다.]An active energy ray-curable peelable pressure-sensitive adhesive composition capable of obtaining a pressure-sensitive adhesive having good adhesive strength before active energy ray irradiation, excellent heat resistance, and excellent peelability (stain resistance, slight tackiness) after active energy ray irradiation even after heating, comprising: An ethylenically unsaturated group-containing acrylic resin containing an ethylenically unsaturated group-containing structural moiety represented by the following formula (1) in the side chain of the resin and having an ethylenically unsaturated group content of 25 to 500 mmol relative to the ethylenically unsaturated group-containing acrylic resin. A pressure-sensitive adhesive composition containing a resin is provided.
[Formula 1]

[R ¹ is a substituent containing an ethylenically unsaturated group,
R ² is an organic group containing at least one selected from C, O, N and S
(However, excluding carbamate groups), and X is O or NH.]

Description

Method for producing pressure-sensitive adhesive composition, pressure-sensitive adhesive sheet, and ethylenically unsaturated group-containing acrylic resin

The present invention relates to a pressure-sensitive adhesive composition containing a specific ethylenically unsaturated group-containing acrylic resin, a pressure-sensitive adhesive sheet, and a method for producing an ethylenically unsaturated group-containing acrylic resin, and in particular, temporary surface protection of metal plates and plastic plates, semiconductor wafers, etc. It is related with the adhesive composition useful for the adhesive sheet for semiconductor fixings, such as a dicing process.

Active energy ray-curable resin compositions that are cured by irradiation with active energy rays such as ultraviolet rays or electron beams are known, and are used for applications such as adhesives, pressure-sensitive adhesives, paints, inks, coating materials, and stereoscopic molding materials. In addition, the active energy ray-curable resin composition is also used as a pressure-sensitive adhesive layer of a pressure-sensitive adhesive sheet for surface protection for temporarily protecting the surface for the purpose of preventing contamination or damage of a member to be processed in processing steps such as cutting or drilling of electronic parts. In recent years, the pressure-sensitive adhesive sheet for surface protection has been used even when processing various members, not limited to electronic parts.

While the pressure-sensitive adhesive sheet is required to have adequate adhesion to the member to be processed for reasons such as miniaturization of processing and thinning of the processing member in recent years, it is necessary to peel the adhesive sheet for surface protection after completing the role of surface protection. When peeling with little force and without residual adhesive is required.

The active energy ray-curable resin composition used in such a pressure-sensitive adhesive sheet is, for example, blended with an acrylic resin at least one of a monomer and an oligomer having an ethylenically unsaturated group, or containing an ethylenically unsaturated group in the acrylic resin itself. Active energy ray curability is expressed. Among these, the use of an ethylenically unsaturated group-containing acrylic resin in which the acrylic resin itself contains an ethylenically unsaturated group is a point of view that the elastic modulus after curing is easily raised because the acrylic resin itself forms a crosslinked structure by irradiation with active energy rays. , It is advantageous from the viewpoint that uncrosslinked components are difficult to remain on the adherend.

As an acrylic resin containing an ethylenically unsaturated group used for such a pressure-sensitive adhesive sheet for temporary surface protection, for example, in Patent Document 1, about an acrylic polymer copolymerized with 2-hydroxyethyl acrylate, 2-methacryloyloxy An acrylic resin containing an ethylenically unsaturated group by subjecting ethyl isocyanate to urethanization is described.

Further, in Patent Document 2, an acrylic copolymer copolymerized with methacrylic acid is esterified with 2-hydroxyethyl methacrylate, and an adhesive tape for processing electronic parts using an acrylic resin containing an ethylenically unsaturated group is described. there is.

In addition, in recent electronic component manufacturing processes, it is not uncommon for parts with adhesive sheets attached to be exposed to high temperatures. For this reason, adhesive sheets used in electronic component manufacturing processes cannot withstand high temperature conditions. Heat resistance is also required.

Patent Document 1 JP 2010-53346A Patent Document 2 JP 2016-121231A

However, in the technique disclosed in Patent Document 1, although the peelability by active energy ray irradiation at room temperature is good, when exfoliation is performed by active energy ray irradiation after exposure under high temperature conditions of 150 ° C. or higher, acrylic resin during high temperature process. Since the urethane bond, which is the bonded portion of the ethylenically unsaturated group in the substrate, is easily decomposed by heat, the adhesive force is unlikely to decrease even when irradiated with active energy rays, and residual adhesive tends to remain on the adherend during peeling. For this reason, improvement of heat resistance is further calculated|required.

In addition, in the technique disclosed in Patent Document 2, an ethylenically unsaturated group is introduced through an ester bond, but since the main chain portion introducing the unsaturated group has a structure derived from methacrylic acid, a main chain decomposition reaction due to heat easily occurs, and heat resistance is still high. It is falling apart, and further improvement is required.

Therefore, in the present invention, under this background, the active energy ray curing property that can obtain an adhesive having good adhesive strength before active energy ray irradiation, excellent heat resistance, and excellent peelability (stain resistance, slight adhesiveness) after active energy ray irradiation even after heating. A peelable pressure-sensitive adhesive composition is provided.

By the way, the inventors of the present invention use an acrylic resin containing a specific amount of ethylenically unsaturated groups of a specific structure, so that the adhesive strength before active energy ray irradiation is good and the adhesive has excellent heat resistance, and even after heating, peeling after active energy ray irradiation A pressure-sensitive adhesive composition capable of obtaining a pressure-sensitive adhesive having excellent properties (fouling resistance and slight tackiness) was discovered.

In addition, the present inventors reacted hydroxyl group-containing acrylic resin (α) with ethylenically unsaturated group-containing carboxylic acid (β) in the presence of compound (I) represented by the formula (2), which did not have a urethane bond and was resistant even at low temperatures. It has been found that it is possible to add ethylenically unsaturated groups to acrylic resins in yield.

That is, the present invention contains an ethylenically unsaturated group-containing structural moiety represented by the following formula (1) in the side chain of the acrylic resin, and the content of the ethylenically unsaturated group is 25 to 500 mmol/ A pressure-sensitive adhesive composition containing 100 g of an ethylenically unsaturated group-containing acrylic resin is taken as a first summary.

[R ¹ is a substituent containing an ethylenically unsaturated group,

R ² is an organic group containing at least one selected from C, O, N and S

(However, carbamate groups are excluded), and X is O or NH.]

In addition, the present invention makes the pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer in which the pressure-sensitive adhesive composition of the first aspect is crosslinked as a second aspect.

And, the present invention is a method for producing an ethylenically unsaturated group-containing acrylic resin in which a hydroxyl group-containing acrylic resin (α) and an ethylenically unsaturated group-containing carboxylic acid (β) are reacted in the presence of a compound (I) represented by the following formula (2) is the third point.

[Here, R ³ and R ⁴ represent a hydrocarbon group having 1 to 20 carbon atoms.]

The pressure-sensitive adhesive composition of the present invention contains an ethylenically unsaturated group-containing structural moiety represented by the following formula (1) in the side chain of an acrylic resin, and the content of the ethylenically unsaturated group is 25 to 500 mmol relative to the ethylenically unsaturated group-containing acrylic resin / 100 g of an ethylenically unsaturated group-containing acrylic resin. For this reason, since the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer crosslinked with this pressure-sensitive adhesive composition contains an acrylic resin containing a predetermined amount of a specific ethylenically unsaturated group-containing structural site in the side chain, the adhesive strength before active energy ray irradiation and the active energy ray irradiation It is excellent in peelability after. Moreover, since the said ethylenically unsaturated group-containing structural part does not have a carbamate group, the said adhesive composition and the said adhesive sheet are excellent in heat resistance, and are excellent in peelability after irradiation with an active energy ray even after heating to high temperature.

[Formula 1]

[R ¹ is a substituent containing an ethylenically unsaturated group,

R ² is an organic group containing at least one selected from C, O, N and S

(However, excluding carbamate groups), and X is O or NH.]

Moreover, especially in this invention, when the said ethylenically unsaturated group containing acrylic resin contains a hydroxyl group, the adhesive force before active energy ray irradiation becomes more excellent.

Moreover, when the adhesive composition of this invention contains a crosslinking agent, the adhesive force before active energy ray irradiation will become more outstanding.

Further, when the pressure-sensitive adhesive composition of the present invention contains a photopolymerization initiator, the curability of the ethylenically unsaturated group-containing acrylic resin is improved by active energy ray irradiation, and the peelability after active energy ray irradiation becomes more excellent.

In addition, especially in the present invention, the ethylenically unsaturated group-containing acrylic resin is a hydroxyl group-containing acrylic resin (α) and an ethylenically unsaturated group-containing carboxylic acid (β) in the presence of the compound (I) represented by the formula (2) If it is made by making it react, an ethylenically unsaturated group-containing acrylic resin can be obtained in high yield. For this reason, the adhesive force before active energy ray irradiation and the releasability after active energy ray irradiation become more excellent, and the heat resistance is excellent, and the releasability after active energy ray irradiation becomes excellent even after heating at a high temperature.

And, especially in the present invention, if the ethylenically unsaturated group-containing acrylic resin is formed by esterification of a hydroxyl group-containing acrylic resin (α) and (meth)acrylic acid anhydride (γ), an ethylenically unsaturated group-containing acrylic resin in high yield can be obtained. For this reason, the adhesive force before active energy ray irradiation and the releasability after active energy ray irradiation become more excellent, and the heat resistance is excellent, and the releasability after active energy ray irradiation becomes excellent even after heating at a high temperature.

Further, according to the production method of the present invention, since the hydroxyl group-containing acrylic resin (α) and the ethylenically unsaturated group-containing carboxylic acid (β) are reacted in the presence of the compound (I) represented by the formula (2), ethylene is produced in a high yield. A sexually unsaturated group-containing acrylic resin can be obtained. In addition, this manufacturing method can obtain an ethylenically unsaturated group-containing acrylic resin that is very suitable even for applications exposed to high temperatures without requiring a complicated operation for removing by-products after the reaction.

In addition, especially in the production method of the present invention, when the hydroxyl group-containing acrylic resin (α) and the ethylenically unsaturated group-containing carboxylic acid (β) are reacted in the presence of the compound (I) represented by the formula (2), furthermore, 1 When reacted in the presence of one or more types of magnesium compounds and one or more types of alkali metal compounds, an ethylenically unsaturated group-containing acrylic resin can be obtained in a higher yield.

Moreover, especially in the manufacturing method of this invention, when the alkali metal which comprises the said alkali metal compound is lithium, the ethylenically unsaturated group containing acrylic resin can be obtained with a higher yield.

And, especially in the production method of the present invention, when the compound (I) represented by the formula (2) is di-t-butyl dicarbonate, an ethylenically unsaturated group-containing acrylic resin can be obtained in a higher yield.

In addition, especially in the production method of the present invention, when the ethylenically unsaturated group-containing carboxylic acid (β) is reacted in the presence of 0.001 to 1000 mol% of the magnesium compound and 0.001 to 1000 mol% of the alkali metal compound, a higher yield is obtained. An ethylenically unsaturated group-containing acrylic resin can be obtained.

In addition, among the production methods of the present invention, in particular, when the content of the hydroxyl group-containing monomer (a1) constituting the hydroxyl group-containing acrylic resin (α) is 0.1 to 50% by mass with respect to the entire polymerization component, the obtained ethylenically unsaturated group-containing acrylic resin When resin is used as an adhesive, it hardens by irradiating an active energy ray and can have better peelability.

In addition, among the production methods of the present invention, especially when the content of the ethylenically unsaturated group of the ethylenically unsaturated group-containing acrylic resin is 25 to 500 mmol/100g relative to the ethylenically unsaturated group-containing acrylic resin, the obtained ethylenically unsaturated group-containing acrylic resin When using as an adhesive, it hardens by irradiating an active energy ray, and can have better peelability.

And, especially in the production method of the present invention, when the acid value of the hydroxyl group-containing acrylic resin (α) is 10 mgKOH/g or less, gelation does not occur during the reaction, and an ethylenically unsaturated group-containing acrylic resin can be obtained efficiently with a higher yield. there is.

Modes for carrying out the present invention will be specifically described below, but the present invention is not limited thereto.

In the present invention, “(meth)acryl” means acryl or methacryl, “(meth)acryloyl” means acryloyl or methacryloyl, and “(meth)acrylate” means acrylate or methacrylate. each means.

Moreover, "acrylic resin" is resin obtained by polymerizing the polymerization component containing at least 1 sort(s) of (meth)acrylate type monomer.

In the present invention, "sheet" is not specifically divided into "film" and "tape", but is described as meaning including these.

The pressure-sensitive adhesive composition of the present invention is usually mainly used for the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet on the premise of peeling off after being attached to a workpiece member such as a metal plate, a plastic plate, or a semiconductor wafer. The pressure-sensitive adhesive sheet is formed by coating a pressure-sensitive adhesive composition on a base sheet to form a pressure-sensitive adhesive layer, and after bonding to a member to be processed, by irradiating active energy rays, the pressure-sensitive adhesive layer is cured and the adhesive strength is reduced, so that the pressure-sensitive adhesive sheet is easily processed. It can be peeled off from the member.

The pressure-sensitive adhesive composition of the present invention contains an acrylic resin containing a predetermined amount of an ethylenically unsaturated group-containing structural site represented by the following formula (1).

[Formula 1]

[R ¹ is a substituent containing an ethylenically unsaturated group,

R ² is an organic group containing at least one selected from C, O, N and S

(However, excluding carbamate groups), and X is O or NH.]

The acrylic resin containing an ethylenically unsaturated group-containing structural moiety represented by the above formula (1) is obtained by reacting a hydroxyl group-containing acrylic resin (α) with an ethylenically unsaturated group-containing carboxylic acid (β) in the presence of compound (I), or It is obtained by making a hydroxyl-containing acrylic resin ((alpha)) and (meth)acrylic acid anhydride ((gamma)) react. Hereinafter, these components are explained.

[hydroxyl group-containing acrylic resin (α)]

The hydroxyl group-containing acrylic resin (α) is a hydroxyl group-containing monomer (a1), an alkyl (meth)acrylate (a2), preferably a functional group-containing monomer (a3) (except for the hydroxyl group-containing monomer (a1)), Moreover, it is obtained by polymerizing other copolymerizable monomers (a4) as needed.

The hydroxyl group of the hydroxyl group-containing monomer (a1) serves as a reaction site with ethylenically unsaturated group-containing carboxylic acid (β) or (meth)acrylic acid anhydride (γ) in the hydroxyl group-containing acrylic resin (α) after polymerization. In addition, the hydroxyl group also serves as a reaction point with a crosslinking agent described later, and it is preferable to contain more than the amount consumed in the reaction with ethylenically unsaturated group-containing carboxylic acid (β) or (meth)acrylic acid anhydride (γ).

The hydroxyl group-containing monomer (a1) is one excluding methacrylate-based monomers from the viewpoint of heat resistance, and examples thereof include hydroxyl-containing acrylate-based monomers and hydroxyl-containing acrylamide-based monomers. As the hydroxyl group-containing acrylate-based monomer or hydroxyl-containing acrylamide-based monomer, specifically, for example, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, 5-hydroxypentyl acrylate, 6 -Acrylic acid hydroxyalkyl esters such as hydroxyhexyl acrylate and 8-hydroxyoctyl acrylate, hydroxyalkyl acrylamides such as 2-hydroxyethyl acrylamide, caprolactone-modified 2-hydroxyethyl acrylate and the like primary hydroxyl group-containing monomers such as lactone-modified monomers, oxyalkylene-modified monomers such as diethylene glycol acrylate and polyethylene glycol acrylate, and 2-acryloyloxyethyl-2-hydroxyethyl phthalic acid; secondary hydroxyl group-containing monomers such as 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, and 3-chloro-2-hydroxypropyl acrylate; Tertiary hydroxyl group containing monomers, such as 2, 2- dimethyl 2-hydroxyethyl acrylate, etc. are mentioned. These can be used individually or in combination of 2 or more types.

Among the hydroxyl group-containing monomers (a1), from the viewpoint of excellent reactivity with ethylenically unsaturated group-containing carboxylic acid (β) or (meth)acrylic acid anhydride (γ) described later, a primary hydroxyl group-containing monomer is preferable, particularly 2- Hydroxyethyl acrylate and 4-hydroxybutyl acrylate are preferred.

The content of the hydroxyl group-containing monomer (a1) is usually 0.1 to 50% by weight, preferably 5 to 40% by weight, more preferably 10 to 35% by weight, based on the total polymeric components of the hydroxyl group-containing acrylic resin (α). am. If such a content is too large, crosslinking proceeds before the drying step, which tends to cause problems in coatability. If too small, a sufficient amount of ethylenically unsaturated group-containing carboxylic acid (β) or (meth)acrylic acid anhydride (γ) ), and the peelability after active energy ray irradiation tends to decrease.

The said alkyl (meth)acrylate (a2) is a main component of the polymerization component which obtains the hydroxyl-containing acrylic resin ((alpha)). In the alkyl (meth)acrylate (a2), the number of carbon atoms in the alkyl group is usually 1 to 24, preferably 1 to 20, particularly preferably 1 to 12, still more preferably 1 to 8. If the number of carbon atoms is too large, the polymerizability is lowered, so it tends to remain as an unreacted monomer in the hydroxyl group-containing acrylic resin (α), and contamination of the workpiece or residual adhesive tends to occur.

Specific examples of the alkyl (meth)acrylate (a2) include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-propyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (metha)acrylate ) Aliphatic (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, etc. acrylic acid alkyl ester; and alicyclic (meth)acrylic acid alkyl esters such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate. These can be used independently and can also use 2 or more types together.

Among the alkyl (meth) acrylates (a2), methyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl from the viewpoints of copolymerizability, adhesive properties, ease of handling, and ease of raw material availability (meth)acrylates are preferred.

In addition, the content of the alkyl (meth)acrylate (a2) is usually 30 to 99% by weight, preferably 40 to 95% by weight, particularly preferably 40 to 95% by weight with respect to the total polymerization components of the hydroxyl group-containing acrylic resin (α). is 50 to 90% by weight. When such a content is too small, the adhesive force before active energy ray irradiation tends to decrease easily, and when too large, the adhesive force before active energy ray irradiation tends to increase too much.

In the present invention, from the viewpoint of excellent reaction with the crosslinking agent described later, it is preferable to contain a hydroxyl group in the acrylic resin. is also desirable

Examples of the functional group-containing monomer (a3) include a carboxy-containing monomer, an amino group-containing monomer, an amide group-containing monomer, a glycidyl group-containing monomer, a sulfonic acid group-containing monomer, and an acetacetyl group-containing monomer. Moreover, these functional group containing monomers can be used individually or in combination of 2 or more types.

Examples of the carboxy-containing monomer include (meth)acrylic acid, (meth)acrylic acid dimer, crotonic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid, glutaconic acid, itaconic acid, and acrylamide N-glycolic acid. , cinnamic acid, and the like. Among them, (meth)acrylic acid is preferably used from the viewpoint of copolymerizability.

The content of the carboxy-containing monomer is usually 1% by weight or less, preferably 0.5% by weight or less, and more preferably 0.3% by weight or less with respect to the total polymerization components of the hydroxyl group-containing acrylic resin (α). If such a content is too large, the quality of the workpiece tends to deteriorate, and crosslinking proceeds before the drying step, resulting in problems in coatability.

Examples of the amino group-containing monomer include N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate.

The content of the amino group-containing monomer is usually 10% by weight or less, preferably 5% by weight or less, and more preferably 2% by weight or less with respect to the total polymerization components of the hydroxyl group-containing acrylic resin (α). When such a content is too large, crosslinking proceeds before the drying step, and there is a tendency that problems in coatability tend to occur.

As the amide group-containing monomer, for example, ethoxymethyl (meth) acrylamide, n-butoxymethyl (meth) acrylamide, (meth) acryloylphospholine, dimethyl (meth) acrylamide, diethyl ( and (meth)acrylamide monomers such as meth)acrylamide, dimethylaminopropyl acrylamide, (meth)acrylamide, and N-methylol (meth)acrylamide.

The content of the amide group-containing monomer is usually 30% by weight or less, preferably 25% by weight or less, and more preferably 20% by weight or less with respect to the total polymerization components of the hydroxyl group-containing acrylic resin (α). When such a content is too large, crosslinking proceeds before the drying step, and there is a tendency that problems in coatability tend to occur.

Examples of the glycidyl group-containing monomer include glycidyl methacrylate and allylglycidyl methacrylate.

The content of the glycidyl group-containing monomer is usually 20% by weight or less, preferably 15% by weight or less, and more preferably 10% by weight or less with respect to the entire polymerization component of the hydroxyl group-containing acrylic resin (α). When such a content is too large, crosslinking proceeds before the drying step, and there is a tendency that problems in coatability tend to occur.

Examples of the sulfonic acid group-containing monomer include olefinsulfonic acids such as ethylenesulfonic acid, allylsulfonic acid and metaallylsulfonic acid, 2-acrylamide-2-methylolpropanesulfonic acid, styrenesulfonic acid or salts thereof. can be heard

The content of the sulfonic acid group-containing monomer is usually 1% by weight or less, preferably 0.5% by weight or less, and more preferably 0.3% by weight or less with respect to the total polymerization components of the hydroxyl group-containing acrylic resin (α). When such a content is too large, crosslinking proceeds before the drying step, which tends to cause problems in coatability.

As said acetacetyl group containing monomer, 2-(acetacetoxy) ethyl (meth)acrylate, allyl acetic acetate etc. are mentioned, for example.

The content of the acetacetyl group-containing monomer is usually 10% by weight or less, preferably 5% by weight or less, and more preferably 1% by weight or less with respect to the total polymeric components of the hydroxyl group-containing acrylic resin (α). When such a content is too large, crosslinking proceeds before the drying step, and there is a tendency that problems in coatability tend to occur.

Examples of the other copolymerizable monomers (a4) include vinyl ester monomers of carboxylate, such as vinyl acetate, vinyl propionate, vinyl stearate and vinyl benzoate; Phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenyl diethylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, styrene , monomers containing an aromatic ring such as α-methylstyrene; biphenyloxy structure-containing (meth)acrylic acid ester monomers such as biphenyloxyethyl (meth)acrylate; 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, methoxydiethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate Monomers containing an alkoxy group or an oxyalkylene group, such as polypropylene glycol mono(meth)acrylate; Acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, alkyl vinyl ether, vinyl toluene, vinyl pyridine, vinyl pyrrolidone, itaconic acid dialkyl ester, fumaric acid dialkyl ester, allyl alcohol, acryl chloride, methyl vinyl ketones, allyltrimethylammonium chloride, dimethylallylvinyl ketone and the like. These may be used independently or may use 2 or more types together.

The content of the other copolymerizable monomer (a4) is usually 40% by weight or less, preferably 30% by weight or less, and more preferably 25% by weight or less with respect to the total polymeric components of the hydroxyl group-containing acrylic resin (α). When there are too many other copolymerizable monomers (a4), there exists a tendency for adhesive properties to fall easily.

The hydroxyl group-containing acrylic resin (α) used in the present invention is a hydroxyl group-containing monomer (a1), an alkyl (meth)acrylate (a2), preferably a functional group-containing monomer (a3), and, if necessary, other copolymerizable monomers ( It can be obtained by polymerizing a4) as a polymerization component. As such a polymerization method, conventionally well-known methods such as solution radical polymerization, suspension polymerization, bulk polymerization, and emulsion polymerization can usually be appropriately carried out. Among them, production by solution radical polymerization is preferable from the viewpoint of being able to safely and stably produce the hydroxyl group-containing acrylic resin (?) with an arbitrary monomer composition.

The solution radical polymerization is carried out in an organic solvent, for example, monomer components such as hydroxyl group-containing monomers (a1), alkyl (meth)acrylates (a2), functional group-containing monomers (a3), and other copolymerizable monomers (a4), and A polymerization initiator is mixed or added dropwise, and polymerization can be performed in a reflux state or usually at 50 to 98°C for about 0.1 to 20 hours.

Examples of the organic solvent used in the polymerization reaction include aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as hexane, esters such as ethyl acetate and butyl acetate, n-propyl alcohol and isopropyl alcohol. aliphatic alcohols, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; and the like.

As the polymerization initiator, a conventional radical polymerization initiator can be used, and specifically, azo-based polymerization initiators such as azobisisobutyronitrile and azobisdimethylvaleronitrile, benzoyl peroxide, lauroyl peroxide, di- and peroxide-based polymerization initiators such as tert-butyl peroxide and cumene hydroperoxide.

The hydroxyl group-containing acrylic resin (?) obtained by the polymerization method is usually obtained in a solution state. The viscosity at 25°C of the hydroxyl group-containing acrylic resin (?) solution is preferably 5 to 50,000 mPa·s, particularly preferably 10 to 20,000 mPa·s. When such a viscosity is outside the above range, the reaction delay occurs when the hydroxyl group-containing acrylic resin (α) and the ethylenically unsaturated group carboxylic acid compound (β) or (meth)acrylic acid anhydride (γ) are reacted, or the obtained ethylenically unsaturated When a group-containing acrylic resin is used as an adhesive, coating properties tend to decrease. In addition, the measuring method of a viscosity is by E-type viscometer.

The weight average molecular weight of the hydroxyl group-containing acrylic resin (α) is usually 100,000 to 2,000,000, preferably 150,000 to 1,500,000, particularly preferably 200,000 to 1,200,000, particularly preferably 300,000 to 1,000,000. . If the weight average molecular weight is too small, contamination of the workpiece member tends to increase, and if it is too large, the coating property tends to decrease and the cost tends to be disadvantageous.

The degree of dispersion (weight average molecular weight/number average molecular weight) of the hydroxyl group-containing acrylic resin (α) is preferably 20 or less, particularly preferably 10 or less, more preferably 7 or less, and particularly preferably 5 or less. When such a degree of dispersion is too high, contamination of the workpiece member tends to increase. In addition, the lower limit of the degree of dispersion is usually 1.1 from the viewpoint of manufacturing limitations.

The above weight average molecular weight is a weight average molecular weight in terms of standard polystyrene molecular weight, and is calculated on a high-speed liquid chromatograph ("Waters 2695 (main body)" and "Waters 2414 (detector)" manufactured by Nippon Waters Co., Ltd.), column: Shodex GPC KF -806L (exclusion limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical plate number: 10,000 plate / piece, filler material: styrene-divinylbenzene copolymer, filler particle size: 10 μm) 3 pieces It is measured by using them in series, and the number average molecular weight can also be obtained in the same way.

The glass transition temperature (Tg) of the hydroxyl group-containing acrylic resin (α) is usually 40°C or less, preferably -70 to 20°C, particularly preferably -65 to 0°C, still more preferably -60 to - It is 10 ℃. When the glass transition temperature is too high, the adhesiveness tends to decrease, and when the glass transition temperature is too low, contamination to the workpiece tends to increase.

In addition, the glass transition temperature (Tg) is a value calculated by applying the glass transition temperature and weight fraction when each monomer constituting the hydroxyl group-containing acrylic resin (α) is a homopolymer to the following Fox formula.

Tg: glass transition temperature (K) of hydroxyl group-containing acrylic resin (α)

Tga: glass transition temperature of homopolymer of monomer A (K)

Wa: weight fraction of monomer A

Tgb: glass transition temperature of homopolymer of monomer B (K)

Wb: weight fraction of monomer B

Tgn: glass transition temperature of homopolymer of monomer N (K)

Wn: weight fraction of monomer N

(Wa+Wb+…Wn=1)

Here, the glass transition temperature when the monomer constituting the hydroxyl group-containing acrylic resin (α) is a homopolymer is usually measured by a differential scanning calorimeter (DSC), and is based on JIS K 7121-1987 or JIS K 6240 can be measured in one way.

Moreover, the acid value of the hydroxyl group-containing acrylic resin (?) is preferably 10 mgKOH/g or less, particularly preferably 5 mgKOH/g or less, more preferably 2 mgKOH/g or less, and particularly preferably 1 mgKOH/g or less. When the above range is exceeded, gelation tends to occur during production.

The acid value of the hydroxyl group-containing acrylic resin (α) can be determined as follows.

That is, a solution of hydroxyl group-containing acrylic resin (?) having a solid content of Z% by weight is collected in a beaker (Yg), and dissolved in a mixed solvent of toluene:methanol = 7:3 (weight ratio). After dissolution, an appropriate amount of phenolphthalein was added and titration was performed with a potassium hydroxide (KOH) solution while stirring with a stirrer, and the KOH solution amount XmL at the time when the solution turned pale pink was read as an end point, Calculate the acid value. In addition, although 0.1 mol/L of KOH solution is usually used, when the acid value of the hydroxyl group-containing acrylic resin (?) is low, a 0.01 mol/L KOH solution may be used to improve accuracy.

[Equation 1]

Acid value (mgKOH/g) = X×(f×M×56.11)/(Y×Z/100)

f: factor of KOH solution

M: molar concentration of KOH solution (mol/L)

X: amount of KOH solution (mL)

Y: sample amount of hydroxyl group-containing acrylic resin (g)

Z: solid content of hydroxyl group-containing acrylic resin (% by weight)

[Ethylenically unsaturated group-containing carboxylic acid (β)]

In the present invention, the ethylenically unsaturated group-containing carboxylic acid (β) used together with the hydroxyl group-containing acrylic resin (α) can be represented by “R ⁵ -COOH”, where R ⁵ is a substituent having an ethylenically unsaturated group. Specifically as the ethylenically unsaturated group-containing carboxylic acid (β), for example, (meth)acrylic acid, β-carboxyethyl (meth)acrylate, (meth)acrylic acid dimer, crotonic acid, maleic acid, maleic anhydride , fumaric acid, citraconic acid, glutaconic acid, itaconic acid, acrylamide-N-glycolic acid, and cinnamic acid. Especially, from a reactive viewpoint, (meth)acrylic acid and (beta)-carboxyethyl (meth)acrylate are preferable. These can be used individually or in combination of 2 or more types.

[Compound (I)]

In the present invention, as the compound (I) used together with the hydroxyl group-containing acrylic resin (α) and the ethylenically unsaturated group-containing carboxylic acid (β), a compound represented by the following formula (2) can be used. Compound (I) represented by the following formula (2) produces an intermediate containing a component derived from the compound by reaction, but the finally obtained ethylenically unsaturated group-containing acrylic resin does not contain a component derived from compound (I) .

[Formula 2]

[Here, R ³ and R ⁴ represent a hydrocarbon group having 1 to 20 carbon atoms.]

In the compound represented by Formula 2, R ³ and R ⁴ each represent a hydrocarbon group. Moreover, the carbon number of the said hydrocarbon group is 1-20 from a viewpoint of availability, Preferably it is 2-10, Especially preferably, it is 3-7.

In Formula 2, R ³ and R ⁴ may be hydrocarbon groups, and their types and structures are not limited. As said hydrocarbon group, an alkyl group, an alkenyl group, an alkynyl group etc. are mentioned specifically, for example. These may be linear, branched or cyclic structures. Moreover, an aryl group is mentioned as said hydrocarbon group. In addition, these hydrocarbon groups may contain an ether bond in their structure, and R ³ and R ⁴ may bond to form a cyclic structure.

Specific examples of the compound (I) represented by the formula (2) include diallyl dicarbonate, di-t-butyl dicarbonate, di-t-amyl dicarbonate, and dibenzyl dicarbonate. . Among these, di-t-butyl dicarbonate in which R ³ and R ⁴ are t-butyl groups is preferable because an ethylenically unsaturated group-containing acrylic resin can be efficiently produced.

As the compound (I) represented by the above formula (2), a commercially available compound can be used, but one obtained by manufacturing by a known method or the like can also be used. Moreover, compound (I) may be used independently and may use 2 or more types together.

[(meth)acrylic acid anhydride (γ)]

The (meth)acrylic acid anhydride (γ) used in the present invention is a compound represented by the following formula (3).

[R ⁶ is hydrogen or a methyl group.]

[Method for producing acrylic resin containing ethylenically unsaturated group]

The ethylenically unsaturated group-containing acrylic resin used in the present invention is

(i) a method in which a hydroxyl group-containing acrylic resin (α) and an ethylenically unsaturated group-containing carboxylic acid (β) are reacted in the presence of the compound (I) represented by the formula (2);

(ii) a method of carrying out an esterification reaction between a hydroxyl group-containing acrylic resin (α) and (meth)acrylic acid anhydride (γ);

can be produced by

Among these, the manufacturing method of said (i) is preferable from a viewpoint of reaction efficiency.

In addition, in each of the above production methods, it is preferable to carry out the reaction in the presence of a catalyst described later from the viewpoint of reaction efficiency.

Here, "in the presence of a catalyst" means that the catalyst only needs to be present in at least a part of the reaction process, and it is not necessary to always exist in all the steps in the reaction process. In each of the above production methods, when a catalyst is added into the reaction system, the requirement of "in the presence of a catalyst" is satisfied. For example, after a catalyst is added into the reaction system, even if any change occurs in the catalyst in the course of the reaction, the requirement of "in the presence of a catalyst" is satisfied.

The form of the reaction container used for each reaction of said (i) and (ii) is not specifically limited. In addition, raw materials used in the reaction [in the case of (i) above, a hydroxyl group-containing acrylic resin (α), an ethylenically unsaturated group-containing carboxylic acid (β) and a compound (I), in the case of (ii) above, a hydroxyl group-containing The method of introducing the acrylic resin (α) and (meth)acrylic acid anhydride (γ)], the catalyst, etc. into the reaction vessel is not particularly limited either, and for example, all raw materials and catalysts are introduced into the reaction vessel at once. method, a method in which some or all of the raw materials, catalysts, etc. are introduced stepwise into the reaction vessel, a method in which some or all of the raw materials, catalysts, etc. are continuously introduced into the reaction vessel, and the like. Moreover, these methods can also be combined.

Hereinafter, each manufacturing method is detailed.

[Production method of (i)]

The reaction conditions in the production method of the above (i) are not particularly limited, and the reaction conditions may be appropriately changed in the course of the reaction.

The amount of the ethylenically unsaturated group-containing carboxylic acid (β) in the production method of (i) above is based on 100 mol% of the total amount of the hydroxyl group-containing monomer (a1) in the hydroxyl group-containing acrylic resin (α). Carboxylic acid (β) is usually 10 to 100 mol%, preferably 15 to 95 mol%, particularly preferably 20 to 90 mol%. If the amount of the ethylenically unsaturated group-containing carboxylic acid (β) is too small, the yield of the ethylenically unsaturated group-containing acrylic resin tends to be low, and if the amount of the ethylenically unsaturated group-containing carboxylic acid (β) is too large, the reaction It is not economical because the load to the subsequent post-treatment process tends to increase.

The amount of the ethylenically unsaturated group-containing carboxylic acid (β) is usually 10 to 1000 mol%, preferably 20 to 500 mol%, based on 100 mol% of the compound (I). Especially preferably, it is 50-200 mol%. If the amount of the ethylenically unsaturated group-containing carboxylic acid (β) is too small, the yield of the ethylenically unsaturated group-containing acrylic resin tends to be low, and if the amount of the ethylenically unsaturated group-containing carboxylic acid (β) is too large, the reaction It is not economical because the load in the subsequent post-treatment process tends to increase.

The reaction temperature is not particularly limited, but the production method (i) can be reacted at a relatively low temperature. The reaction temperature is usually 0 to 180°C, preferably 20 to 100°C, and particularly preferably 40 to 70°C. When the reaction temperature is too low, the reaction efficiency tends to decrease, and when the reaction temperature is too high, by-products tend to increase, and the ethylenically unsaturated group-containing acrylic resin tends to be colored.

Also, the reaction time is not particularly limited, but is usually 0.5 to 72 hours, preferably 2 to 48 hours. If the reaction time is too short, the reaction tends not to proceed sufficiently, and even if the reaction time is too long, there is a tendency that the yield cannot be improved, so it is not economical.

In addition, in the manufacturing method of (i), the atmosphere and pressure at the time of reaction are not specifically limited, either.

Further, in the production method (i), when reacting the hydroxyl group-containing acrylic resin (α) and the ethylenically unsaturated group-containing carboxylic acid (β) in the presence of compound (I), one or more magnesium compounds and one or more magnesium compounds are used as catalysts. It is preferable to contain the above alkali metal compound. When the reaction is performed in the presence of the catalyst, an ethylenically unsaturated group-containing acrylic resin can be obtained in a higher yield.

[Magnesium compound]

Examples of the magnesium compound include oxides of magnesium, hydroxide salts, carbonates, hydrogen carbonates, silicates, lactates, ammonium sulfate salts, nitrates, phosphates, hydrogen phosphates, ammonium phosphate salts, borates, halides, perhalogenates, and hydrogen halides. salts with inorganic acids such as acid salts; Salts with organic acids, such as carboxylate, percarboxylate, and sulfonic acid salt; and complex salts such as acetylacetone salts, hexafluoroacetylacetone salts, porphyrin salts, phthalocyanine salts, and cyclopentadiene salts. A salt of these magnesium may be either a hydrate or an anhydride. Among them, magnesium oxides, hydroxide salts, carbonates, lactates, ammonium sulfate salts, nitrates, hydrohalide salts, carboxylic acid salts, and complex salts are preferable.

More specifically, as the magnesium compound, for example, magnesium oxide, magnesium hydroxide, magnesium carbonate hydroxide (alias: alkaline magnesium carbonate), magnesium sulfate, magnesium ammonium sulfate, magnesium acetate, magnesium chloride, magnesium bromide, magnesium acetate, Magnesium benzoate, magnesium (meth)acrylate, and magnesium acetylacetone are mentioned. Among these, magnesium hydroxide is preferable.

As these magnesium compounds, commercially available ones can be used, but those obtained by manufacturing by a known method or the like can also be used. Moreover, a magnesium compound can be used individually or in combination of 2 or more types.

The amount of the magnesium compound used is not particularly limited as long as the ethylenically unsaturated group-containing acrylic resin can be produced, but is usually 0.001 to 1000 mol%, preferably 0.005 to 500 mol%, relative to the ethylenically unsaturated group-containing carboxylic acid (β). %, and particularly preferably 0.01 to 250 mol%. If the amount of the magnesium compound used is too small, it tends to be difficult to obtain the effect of further increasing the yield of the ethylenically unsaturated group-containing acrylic resin, and even if the amount of the magnesium compound used is too large, there is a tendency that no further improvement in yield can be seen Not economical.

[Alkali metal compound]

Examples of the alkali metal compound include alkali metal hydrogen salts, oxides, hydroxide salts, carbonates, hydrogen carbonates, lactates, nitrates, phosphates, borates, halides, perhalogenates, hydrohalides, thiocyanates, etc. salts of with inorganic acids; salts with organic acids such as alkoxide salts, carboxylic acid salts and sulfonic acid salts; salts with organic bases such as amide salts and sulfonamide salts; and complex salts such as acetylacetone salts, hexafluoroacetylacetone salts, porphyrin salts, phthalocyanine salts, and cyclopentadiene salts. These alkali metal salts may be either a hydrate or an anhydride. Among these, oxides, hydroxide salts, carbonates, hydrogencarbonates, hydrohalides, carboxylates, amide salts, and complex salts of alkali metals are preferable.

In addition, as the alkali metal constituting the alkali metal compound, for example, lithium, sodium, potassium, rubidium, and cesium are preferable, and catalytic activity is high, and an ethylenically unsaturated group-containing acrylic resin can be obtained in high yield. from lithium is more preferred.

Specific examples of the lithium compound include lithium oxide, lithium hydroxide, lithium carbonate, lithium fluoride, lithium chloride, lithium bromide, lithium acetate, lithium benzoate, lithium (meth)acrylate, lithium amide, and lithium trifluimide. , acetylacetone lithium, and the like. Among these, lithium hydroxide is preferable.

Although a commercially available thing can be used for the said alkali metal compound, the thing obtained by manufacture by a well-known method etc. can also be used. Moreover, an alkali metal compound may be used independently and may use 2 or more types together.

The amount of the alkali metal compound used is not particularly limited as long as the ethylenically unsaturated group-containing acrylic resin can be produced, but is usually 0.001 to 1000 mol%, preferably 0.005 to 500 mol%, relative to the ethylenically unsaturated group-containing carboxylic acid (β). %, and particularly preferably 0.01 to 250 mol%. If the amount of the alkali metal compound used is too small, the effect of further increasing the yield of the ethylenically unsaturated group-containing acrylic resin tends to be difficult to obtain, and even if the amount of the alkali metal compound used is too large, no further improvement in the yield tends to be seen. It is not economical

[Other optional ingredients]

In addition, in the manufacturing method of (i), a solvent can also be used as another arbitrary component. As the solvent, the same organic solvents listed in the production of the hydroxyl group-containing acrylic resin (?) can be used. A solvent may be used individually by 1 type, and a mixed solvent of 2 or more types may be sufficient as it. The usage amount of the solvent is not particularly limited either, and can be selected appropriately. The method for introducing the solvent into the reaction vessel is not particularly limited, and all solvents may be introduced at once, some or all solvents may be introduced stepwise, or some or all solvents may be introduced continuously. may be Moreover, an introduction method combining these methods may be used.

[Production method of (ii)]

The conditions of the esterification reaction in the production method (ii) are not particularly limited, and the reaction conditions may be appropriately changed in the course of the reaction.

The amount of the hydroxyl group-containing acrylic resin (α) and (meth)acrylic acid anhydride (γ) is usually based on 100 mol% of the hydroxyl group-containing monomer (a1) in the hydroxyl group-containing acrylic resin (α). 10 to 100 mol%, preferably 15 to 95 mol%, particularly preferably 20 to 90 mol%.

The reaction temperature of the esterification reaction is usually 20 to 90°C, preferably 30 to 80°C, and the reaction time is usually 2 to 40 hours, preferably 5 to 30 hours.

In addition, in the manufacturing method of (ii), the atmosphere and pressure at the time of reaction are not specifically limited, either.

[Magnesium compound]

Moreover, when carrying out the esterification reaction of hydroxyl-containing acrylic resin and (meth)acrylic acid anhydride in the manufacturing method of (ii), it is preferable to use a magnesium compound as a catalyst. As the magnesium compound, the same magnesium compounds listed in the production method of (i) above can be used. Moreover, a magnesium compound can be used individually or in combination of 2 or more types. Among these, salts with inorganic acids, salts with organic acids, and complex salts of magnesium are preferred, and hydroxides, carboxylates, and acetylacetone salts of magnesium are more preferred, and magnesium hydroxide and magnesium (meth)acrylate are particularly preferred. , acetylacetone magnesium.

The amount of the magnesium compound used is usually 0.01 to 10 mol%, preferably 0.05 to 5 mol%, particularly preferably 0.1 to 1 mol%, based on 100 mol% of the hydroxyl group-containing monomer (a1) in the hydroxyl group-containing acrylic resin (α). am.

[Other optional ingredients]

In addition, in the production method of (ii), a solvent may be used as other optional components, and as the solvent, the same solvent as described for polymerization of the hydroxyl group-containing acrylic resin (α) can be used. A solvent may be used individually by 1 type, and a mixed solvent of 2 or more types may be sufficient as it. In addition, the usage amount of the solvent and the introduction method into the reaction vessel are the same as those in the above (i) production method.

[Acrylic resin containing ethylenically unsaturated group]

In this way, an acrylic resin containing an ethylenically unsaturated group-containing structural moiety represented by, for example, the following formula (1) can be efficiently obtained by the production method (i) or (ii) above. In addition, "R ¹ " in the following general formula is a substituent containing an ethylenically unsaturated group.

[Formula 1]

[R ¹ is a substituent containing an ethylenically unsaturated group,

R ² is an organic group containing at least one selected from C, O, N and S

(However, excluding carbamate groups), and X is O or NH.]

Since the said ethylenically unsaturated group-containing acrylic resin contains a predetermined amount of specific ethylenically unsaturated group site|parts in a side chain, it hardens by irradiating an active energy ray, and has peelability. Further, the ethylenically unsaturated group structural moiety represented by the formula (1) may be a side chain terminal of an acrylic resin, for example, the ethylenically unsaturated group-containing structural moiety may be directly bonded as a side chain to the main chain of the acrylic resin, The ethylenically unsaturated group-containing structural site may be bonded to the side chain terminal of the acrylic resin having a side chain. And the adhesive composition of this invention containing this ethylenically unsaturated group containing acrylic resin is excellent in the adhesive force before active energy ray irradiation and the peelability after active energy ray irradiation. Moreover, since the said ethylenically unsaturated group-containing acrylic resin does not have a carbamate group at the ethylenically unsaturated group-containing structural site|part, it is excellent in heat resistance and is excellent in peelability after active energy ray irradiation even after heating at high temperature.

The ethylenically unsaturated group introduction rate (esterification rate) of the ethylenically unsaturated group-containing acrylic resin is usually 10% or more, preferably 20% or more, particularly Preferably it is 30% or more. In addition, the upper limit is usually 100%, and when applying the hydroxyl group derived from the hydroxyl group-containing monomer (a1) to the reaction with the crosslinking agent described later, it is preferable to set 95% as the upper limit. In addition, the upper limit of the reaction rate of the ethylenically unsaturated group-containing carboxylic acid (β) or (meth)acrylic acid anhydride (γ) is usually 100%. When the ethylenically unsaturated group introduction rate is too low, the peelability after active energy ray irradiation tends to decrease. In addition, the ethylenically unsaturated group introduction rate is calculated by the following formula (2) from the integral value ratio of the hydroxyl group-containing monomer (a1) before and after the esterification reaction by ¹³ C-NMR measurement.

OH (α): integral value derived from the hydroxyl group-containing monomer (a1) in the hydroxyl group-containing acrylic resin (α)

OH(A): integral value derived from hydroxyl group-containing monomer (a1) in ethylenically unsaturated group-containing acrylic resin

The ethylenically unsaturated group-containing acrylic resin has an ethylenically unsaturated group content of 25 to 500 mmol/100 g relative to the ethylenically unsaturated group-containing acrylic resin. It is preferably 30 to 450 mmol/100 g, more preferably 40 to 400 mmol/100 g, and particularly preferably 50 to 300 mmol/100 g. When the content of the ethylenically unsaturated group is too small, the peelability upon active energy ray irradiation decreases, and when the content of the ethylenically unsaturated group is too large, the contamination resistance of the member to be processed after peeling decreases.

Content of the ethylenically unsaturated group of the said ethylenically unsaturated group containing acrylic resin can be calculated|required by the following calculation.

E(a): number of moles of esterified hydroxyl group-containing monomer (a1)

Mw (γ): Molecular weight of unsaturated groups added by esterification

In addition, E(a) is the product of the weight % of the hydroxyl group-containing monomer (al) in 100% by weight of the polymerized component of the hydroxyl group-containing acrylic resin (α) and the ethylenically unsaturated group introduction ratio divided by the molecular weight of the hydroxyl group-containing monomer (a1) will be.

In addition, when the ethylenically unsaturated group-containing acrylic resin contains a hydroxyl group, it reacts with a crosslinking agent described below to form a crosslinked structure, thereby improving the adhesive force before active energy ray irradiation, which is preferable.

The content of the hydroxyl group in the ethylenically unsaturated group-containing acrylic resin is usually 0.01 to 35% by weight, preferably 0.01 to 25% by weight. If the content of hydroxyl groups is too small, the cohesive strength of the adhesive decreases, which tends to cause residual adhesive, and if the content of hydroxyl groups is too large, the flexibility and adhesive strength of the adhesive decrease, which tends to cause floating between members to be processed. there is In addition, the hydroxyl group contained in the ethylenically unsaturated group-containing acrylic resin is after esterification of the hydroxyl group-containing acrylic resin (α) and the ethylenically unsaturated group-containing carboxylic acid (β) or (meth)acrylic acid anhydride (γ) means a hydroxyl group derived from the unreacted hydroxyl group-containing monomer (a1).

Moreover, when using the said ethylenically unsaturated group containing acrylic resin as an adhesive, a solution state is preferable. The viscosity at 25°C of the ethylenically unsaturated group-containing acrylic resin solution is preferably 5 to 50,000 mPa·s, particularly preferably 10 to 10,000 mPa·s. When such a viscosity is outside the above range, the coatability when the ethylenically unsaturated group-containing acrylic resin is used as an adhesive tends to decrease. In addition, the measuring method of a viscosity is by E-type viscometer.

[Crosslinking agent]

In order to improve the adhesive force before active energy ray irradiation to the adhesive composition of this invention, it is preferable to further contain a crosslinking agent. As described above, the crosslinking agent reacts with a functional group in the ethylenically unsaturated group-containing acrylic resin to form a crosslinking structure, and examples include an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, a melamine crosslinking agent, an aldehyde crosslinking agent, An amine type crosslinking agent and a metal chelate type crosslinking agent are mentioned. Among these, it is preferable to use an isocyanate-based crosslinking agent from the viewpoint of improving adhesiveness with an adherend or from the viewpoint of reactivity with an ethylenically unsaturated group-containing acrylic resin.

The isocyanate-based crosslinking agent contains at least two or more isocyanate groups, and examples thereof include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, and isocyanates. Alicyclic polyisocyanates such as phorone diisocyanate and hydrogenated diphenylmethane diisocyanate, and their biuret forms, isocyanurate forms, and ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, castor oil, etc. and adducts that are reactants with low-molecular-weight active hydrogen-containing compounds. Among these, from the viewpoint of drug resistance and reactivity with functional groups, aromatic polyisocyanates and adducts of aromatic polyisocyanates and trimethylolpropane are preferable, and adducts of tolylene diisocyanate and trimethylolpropane are particularly preferable.

Examples of the epoxy-based crosslinking agent include 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane and N,N,N',N'-tetraglycidyl-m-xylene. diamine, ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidyl aniline, diglycidyl amine and the like.

Examples of the aziridine-based crosslinking agent include diphenylmethane-4,4'-bis(1-aziridinecarboxamide), trimethylolpropanetri-β-aziridinylpropionate, and tetramethylolmethanetri-β. -aziridinylpropionate, toluene-2,4-bis(1-aziridinecarboxamide), triethylenemelamine, bisisophthaloyl-1-(2-methylaziridine), tris-1-(2- Methyl aziridine) phosphine oxide, trimethylolpropane tri-β-(2-methyl aziridine) propionate, etc. are mentioned.

Examples of the melamine-based crosslinking agent include methylolmelamine derivatives such as melamine, amino group-containing methylolmelamine obtained by condensing melamine and formaldehyde, imino group-containing methylolmelamine, and hexamethylolmelamine, and methylolmelamine derivatives with methyl alcohol or partially or completely etherified methylol melamine by reaction with a lower alcohol such as butyl alcohol or partially or completely alkylated methylol melamine, partially or completely alkylated methylol melamine containing an imino group or partially alkylated methylol melamine, and the like.

The aldehyde-based crosslinking agent is, for example, formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, glyoxal, glutalaldehyde, dialdehyde starch, hexamethylenetetramine, 1,4-dioxane-2,3-diol Aldehyde-based compounds that release aldehyde in aqueous solutions, such as 1,3-bis(hydroxymethyl)-2-imidazolidine, dimethylol urea, N-methylol acrylamide, urea formalin resin, and melamine formalin resin, or and aromatic aldehyde-based compounds such as benzaldehyde, 2-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxybenzaldehyde, and m-hydroxybenzaldehyde.

Examples of the amine crosslinking agent include 4,4'-methylene-bis(2-chloroaniline), modified 4,4'-methylenebis(2-chloroaniline), and diethyltoluenediamine.

Examples of the metal chelate crosslinking agent include chelate compounds of metal atoms such as aluminum, zirconium, titanium, zinc, iron, and tin, and aluminum chelate compounds are preferable from the viewpoint of performance. As an aluminum chelate compound, for example, diisopropoxy aluminum monooleyl acetate acetate, monoisopropoxy aluminum bisoleyl acetate acetate, monoisopropoxy aluminum monooleate monoethyl acetate acetate, diisopropoxy aluminum mono Lauryl acetic acetate, diisopropoxy aluminum monostearylacetate, diisopropoxy aluminum monoisostearylacetate, etc. are mentioned.

The said crosslinking agent may be used independently and may use 2 or more types together.

The content of the crosslinking agent is usually preferably 0.1 to 30 parts by weight, particularly preferably 0.2 to 20 parts by weight, and still more preferably 0.2 to 15 parts by weight, based on 100 parts by weight of the ethylenically unsaturated group-containing acrylic resin. If the crosslinking agent is too small, the cohesive force of the pressure-sensitive adhesive is lowered, which tends to cause residual adhesive, and when the crosslinking agent is too large, the flexibility and adhesive strength of the pressure-sensitive adhesive are lowered, which tends to cause floating between members to be processed.

[Photoinitiator]

It is preferable to mix|blend a photoinitiator in the adhesive composition of this invention from a viewpoint of improving the peelability after active energy ray irradiation. As the photopolymerization initiator, any photopolymerization initiator may generate radicals under the action of light, and examples thereof include diethoxyacetphenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethylketal, and 4-( 2-hydroxyethoxy) phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexylphenylketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy Roxy-2-methyl-1-propan-1-one, 2-methyl-2-morpholino (4-thio methylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholino Polynophenyl)butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2-hydroxy- acetphenones such as 2-methyl-1-[4-(1-methylvinyl)phenyl]propanone oligomer;

benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; Benzophenone, o-benzoylmethylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenylsulfide, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone , 2,4,6-trimethylbenzophenone, 4-benzoyl-N,N-dimethyl-N-[2-(1-oxo-2-propenyloxy)ethyl]benzenemethanaminium bromide, (4-benzoyl benzophenones such as benzyl)trimethylammonium chloride;

2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2-( thioxanthone such as 3-dimethylamino-2-hydroxy)-3,4-dimethyl-9H-thioxanthone-9-one mesochloride;

2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, bis(2,4,6-trimethylbenzoyl) - Acyl phosphon oxides such as phenylphosphine oxide; etc. can be mentioned. Among these, preferred are acetphenones, particularly 1-hydroxycyclohexylphenyl ketone, and thioxantones, particularly 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

In addition, these photoinitiators can be used individually or can use 2 or more types together.

The content of the photopolymerization initiator is preferably 0.1 to 20 parts by weight, particularly preferably 0.5 to 15 parts by weight, particularly preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the ethylenically unsaturated group-containing acrylic resin.

If the content of the photopolymerization initiator is too small, the curability of the ethylenically unsaturated group-containing acrylic resin is low in response to active energy ray irradiation, and the peelability after active energy ray irradiation tends to decrease. Contamination of the member tends to increase.

Moreover, as preparation of these photopolymerization initiators, for example, triethanolamine, triisopropanolamine, 4,4'-dimethylaminobenzophenone (Mihiraketone), 4,4'-diethylaminobenzophenone, 2-dimethylamino Ethylbenzoic acid, 4-dimethylaminobenzoic acid ethyl, 4-dimethylaminobenzoic acid (n-butoxy)ethyl, 4-dimethylaminobenzoic acid isoamyl, 4-dimethylaminobenzoic acid 2-ethylhexyl, 2,4-diethylthioxanthone , 2,4-diisopropylthioxanthone, etc. can also be used in combination. These aids can also be used alone or in combination of two or more.

[Other ingredients]

In the pressure-sensitive adhesive composition of the present invention, in the range of not impairing the effects of the present invention, for example, it is also preferable to blend an ethylenically unsaturated compound from the viewpoint of peelability after active energy ray irradiation, and also an antistatic agent, an antioxidant, a plasticizer, It may further contain additives such as fillers, pigments, diluents, anti-aging agents, ultraviolet absorbers, ultraviolet stabilizers, and tackifying resins. These additives may be used alone or in combination of two or more. Antioxidants are particularly effective in maintaining the stability of the pressure-sensitive adhesive layer. The content in the case of compounding the antioxidant is not particularly limited, but is preferably 0.01 to 5% by weight. In addition to the additives, a small amount of impurities and the like included in the manufacturing raw materials of the components of the pressure-sensitive adhesive composition may be contained.

In this way, the adhesive composition of this invention is obtained by mixing an ethylenically unsaturated group containing acrylic resin, Preferably a crosslinking agent, a photoinitiator, and other components as needed.

The pressure-sensitive adhesive composition of the present invention is crosslinked by the crosslinking agent to exhibit performance as an adhesive, and then, by irradiating with active energy rays, the ethylenically unsaturated group of the ethylenically unsaturated group-containing acrylic resin is polymerized to cure the pressure-sensitive adhesive, thereby reducing the adhesive strength. The deterioration of the peeling property is exhibited.

The pressure-sensitive adhesive composition of the present invention is usually preferably used as a pressure-sensitive adhesive layer of a pressure-sensitive adhesive sheet for temporarily protecting the surface when processing members such as electronic substrates, semiconductor wafers, processed glass products, metal plates, and plastic plates. In addition, since the pressure-sensitive adhesive sheet of the present invention has excellent heat resistance, even when it is applied to the surface of a workpiece and then subjected to a heating step of 100° C. or higher, it exhibits excellent peelability when irradiated with active energy rays.

Hereinafter, the adhesive sheet will be described.

The pressure-sensitive adhesive sheet usually has a base sheet, a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition of the present invention, and a release film. As a method for producing such a pressure-sensitive adhesive sheet, first, the pressure-sensitive adhesive composition of the present invention is directly coated on a release film or base sheet as it is or after adjusting the concentration with an appropriate organic solvent. After that, a pressure-sensitive adhesive sheet can be obtained by drying by, for example, heat treatment at 80 to 105° C. for 0.5 to 10 minutes, and attaching it to a base sheet or a release film. In addition, aging may be further performed after drying in order to balance adhesive physical properties.

Examples of the substrate sheet include polyester-based resins such as polyethylene naphthalate, polyethylene terephthalate, polybutylene terephthalate, and polyethylene terephthalate/isophthalate copolymer; polyolefin resins such as polyethylene, polypropylene, and polymethylpentene; Polyfluoroethylene resins, such as polyvinyl fluoride, polyvinylidene fluoride, and polyfluoroethylene; polyamides such as nylon 6 and nylon 6,6; vinyl polymers such as polyvinyl chloride, polyvinyl chloride/vinyl acetate copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polyvinyl alcohol, and vinylon; cellulosic resins such as cellulose triacetate and cellophane; acrylic resins such as polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, and polybutyl acrylate; polystyrene; polycarbonate; polyarylate; synthetic resin sheets such as polyimide; metal foils of aluminum, copper, and iron; paper such as woodfree paper and glassine paper; and woven and nonwoven fabrics made of glass fibers, natural fibers, synthetic fibers, and the like. These base sheets can be used as a single-layered body or as a multi-layered body in which two or more types are laminated. Among these, synthetic resin sheets are preferable from the viewpoint of weight reduction and the like.

In addition, as the release film, for example, various synthetic resin sheets exemplified as the base sheet, paper, woven fabric, nonwoven fabric, etc. can be used.

In addition, the coating method of the pressure-sensitive adhesive composition is not particularly limited as long as it is a general coating method, and examples thereof include methods such as roll coating, die coating, gravure coating, comma coating, and screen printing.

The thickness of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is usually preferably 10 to 200 μm, and preferably 15 to 100 μm.

As the aging conditions, the temperature is usually room temperature (23°C) to 70°C, and the time is usually 1 to 30 days, specifically, for example, 1 to 20 days at 23°C and 3 to 3 days at 23°C. What is necessary is just to carry out under conditions, such as 10 days and 1 to 7 days at 40 degreeC.

Although the adhesive strength of the adhesive sheet of the present invention is reduced by irradiation with active energy rays, the active energy rays are usually rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, and infrared rays, and electromagnetic waves such as X-rays and γ-rays. , electron beams, proton rays, neutron rays, etc. can be used. Among these, ultraviolet rays are preferable from the viewpoints of curing speed, availability of irradiation equipment, price, and the like.

The cumulative irradiation amount in the case of irradiating the ultraviolet rays is usually 50 to 3,000 mJ/cm 2 , preferably 100 to 1,000 mJ/cm 2 . The irradiation time varies depending on the type of light source, the distance between the light source and the pressure-sensitive adhesive layer, the thickness of the pressure-sensitive adhesive layer, and other conditions, but is usually several seconds, and in some cases, several fractions of a second.

The adhesive strength of the pressure-sensitive adhesive sheet varies depending on the type of base sheet, type of workpiece, etc., but is preferably 0.1 to 30 N/25 mm, and preferably 0.5 to 20 N/25 mm before active energy ray irradiation. Moreover, as for the adhesive force after active energy ray irradiation, 1 N/25 mm or less is preferable, and 0.5 N/25 mm or less is preferable.

The adhesive force after the active energy ray irradiation is preferably 1/10 or less of the adhesive force before the active energy ray irradiation, and more preferably 1/20 or less.

In addition, the adhesive strength of the adhesive sheet of the present invention when heated at 150°C for 1 hour and then subjected to ultraviolet irradiation (accumulated irradiation amount of 250 mJ/cm 2 ) is preferably 1 N/25 mm or less, and is also 0.5 N/25 mm or less. it is desirable

When heated at 150°C for 1 hour, the adhesive force after active energy ray irradiation is preferably 1/5 or less of the adhesive force before active energy ray irradiation, and more preferably 1/10 or less.

Further, the pressure-sensitive adhesive sheet of the present invention has an adhesive strength when heated at 200°C for 1 hour and then subjected to ultraviolet irradiation (accumulated irradiation amount: 250 mJ/cm 2 ) is preferably 2 N/25 mm or less, and more preferably 1 N/25 mm or less. desirable.

When heated at 200°C for 1 hour, the adhesive force after active energy ray irradiation is preferably 1/2 or less of the adhesive force before active energy ray irradiation, more preferably 1/3 or less.

The pressure-sensitive adhesive composition of the present invention, for example, after bonding a pressure-sensitive adhesive sheet using this as an adhesive layer to a member to be processed to temporarily protect the surface of the member to be processed, and then irradiating active energy rays as necessary, the pressure-sensitive adhesive layer is formed. After curing, the adhesive strength is reduced, and it can be easily peeled off from the member to be processed. In addition, since the pressure-sensitive adhesive sheet of the present invention has excellent heat resistance, after attaching it to the surface of a workpiece member, for example, 100 ° C. or higher, for example, even when sticking it to a heating step of 150 ° C. or higher, after that, by irradiating with active energy rays It exhibits excellent peelability.

(Example)

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In addition, below, "part" means a weight basis.

<Preparation of hydroxyl-containing acrylic resin (α) and carboxy-containing acrylic resin (α')>

Prior to Examples, a hydroxyl group-containing acrylic resin (α) and a carboxy group-containing acrylic resin (α') were prepared.

[Preparation Example 1]

Ethyl acetate and azobisisobutyronitrile (AIBN) were placed in a 2 L four-neck flask with a round bottom, and butyl acrylate (BA) and 2-hydroxyethyl acrylate (2HEA) were mixed with reflux for 2 hours. After dripping over, ethyl acetate and AIBN were added suitably, and it was made to react for 7.5 hours, and the hydroxyl-containing acrylic resin ((alpha)-1) solution was obtained.

In addition, the monomer composition of the hydroxyl group-containing acrylic resin (α-1) is BA/2 HEA = 72/28 (weight ratio), the weight average molecular weight is 470,000, the glass transition temperature is -23.7 ° C, the solid content is 45.7% by weight, and the viscosity was 12,600 mPa·s/25°C. Moreover, the acid value of hydroxyl-containing acrylic resin ((alpha)-1) was 0.09 mgKOH/g.

[Preparation Example 2]

Ethyl acetate and azobisisobutyronitrile (AIBN) were placed in a 2 L four-neck flask with a round bottom, and butyl acrylate (BA), methyl methacrylate (MMA), and 2-hydroxyethyl were added while refluxing. After acrylate (2HEA) was dripped over 2 hours, ethyl acetate and AIBN were added suitably, and it was made to react for 7.5 hours, and the hydroxyl-containing acrylic resin ((alpha)-2) solution was obtained.

In addition, the monomer composition of the hydroxyl group-containing acrylic resin (α-2) is BA/MMA/2 HEA = 62/10/28 (weight ratio), the weight average molecular weight is 600,000, the glass transition temperature is -35.3 ° C, and the solid content is 40 The weight % and viscosity were 6,000 mPa·s/25°C. Moreover, the acid value of hydroxyl-containing acrylic resin ((alpha)-2) was 0.09 mgKOH/g.

[Preparation Example 3]

Ethyl acetate and azobisisobutyronitrile (AIBN) were placed in a 2 L four-neck flask with round bottoms, and butyl acrylate (BA) and acrylic acid (AAc) were added dropwise over 2 hours while refluxing, then appropriately Ethyl acetate and AIBN were added and reacted for 7.5 hours to obtain a carboxy-containing acrylic resin (?'-1) solution.

In addition, the monomer composition of the carboxy-containing acrylic resin (α'-1) is BA/AAc = 80/20 (weight ratio), the weight average molecular weight is 710,000, the glass transition temperature is -35.7 ° C, the solid content is 35.0% by weight, and the viscosity was 15,000 mPa·s/25°C. Moreover, the acid value of carboxy-containing acrylic resin ((alpha)'-1) was 156 mgKOH/g.

An ethylenically unsaturated group-containing acrylic resin was produced using the hydroxyl-containing acrylic resin (α) and the carboxy-containing acrylic resin (α') obtained above.

<Production Example 1>

In a 2 L four round-bottomed flask, 80 mol% of acrylic acid (AAc) was added to 100 mol% of the hydroxyl group-containing acrylic resin (α-1) prepared above and the hydroxyl group-containing monomer in the hydroxyl group-containing acrylic resin (α-1) ( β-1), 0.50 mol% of magnesium hydroxide and 0.50 mol% of lithium hydroxide were added to acrylic acid, respectively, and the temperature was raised to 60°C while stirring. Subsequently, a 50% toluene solution of di-t-butyl (I-1) dicarbonate in the same mol as the acrylic acid placed was added dropwise over 6 hours, and further reacted at 60°C for 10 hours to obtain an ethylenically unsaturated group-containing acrylic resin (1). got it During the reaction, no conspicuous increase in viscosity was observed, and the reaction proceeded favorably.

The obtained ethylenically unsaturated group-containing acrylic resin (1) has a solid content of 34.4% by weight, a viscosity of 2,300 mPa s / 25 ° C, and an esterification rate calculated from the results of ¹³ C-NMR measurement is 76.9% (reaction rate is 96.1%), The content of the ethylenically unsaturated group was 165 mmol/100 g.

<Production Example 2>

In a 2 L four round-bottomed flask, 80 mol% of methacrylic anhydride was added to 100 mol% of the hydroxyl group-containing acrylic resin (α-2) prepared above and the hydroxyl group-containing monomer in the hydroxyl group-containing acrylic resin (α-2). (γ-1) and 0.40 mol% of magnesium hydroxide as an esterification catalyst were added and reacted at 50°C for 18 hours with stirring to obtain an ethylenically unsaturated group-containing acrylic resin (2).

The obtained ethylenically unsaturated group-containing acrylic resin (2) has a solid content of 31.8% by weight, a viscosity of 800 mPa s / 25 ° C, and an esterification rate calculated from the results of ¹³ C-NMR measurement is 64% (reaction rate is 80%), and ethylene Content of the sexually unsaturated group was 140 mmol/100g.

<Production Example 3>

In Production Example 2, with respect to 100 mol% of the hydroxyl group-containing monomer in the hydroxyl group-containing acrylic resin (α-2), 33 mol% of methacrylic anhydride (γ-1) and magnesium hydroxide as an esterification catalyst were changed to 0.16 mol%, except that In the same manner as in Production Example 2, an ethylenically unsaturated group-containing acrylic resin (3) was obtained.

The obtained ethylenically unsaturated group-containing acrylic resin (3) has a solid content of 31.9% by weight, a viscosity of 1,000 mPa s / 25 ° C, and an esterification rate calculated from the results of ¹³ C-NMR measurement is 33% (reaction rate is 100%), The content of the ethylenically unsaturated group was 72 mmol/100 g.

<Production Example 4>

With respect to 100 mol% of the hydroxyl group-containing monomer in the hydroxyl group-containing acrylic resin (α-2) obtained in Preparation Example 2, 80 mol% of 2-methacryloyloxyethyl acrylate (MOI) and dibutyltin dilauu as a urethanization catalyst A rate was added appropriately, and it was made to react at 50 degreeC for 18 hours, and the ethylenically unsaturated group containing acrylic resin (1') was obtained.

The obtained ethylenically unsaturated group-containing acrylic resin (1') has a solid content of 35.0% by weight, a viscosity of 1,200 mPa s / 25 ° C, and a urethanization rate calculated from the results of ¹³ C-NMR measurement is 80% (reaction rate is 100%) , and the content of the ethylenically unsaturated group was 148 mmol/100 g.

<Production Example 5>

In Production Example 2, based on 100 mol% of the hydroxyl group-containing monomer in the hydroxyl group-containing acrylic resin (α-2), 8.4 mol% of methacrylic anhydride (γ-1) and magnesium hydroxide as an esterification catalyst were changed to 0.04 mol%. Except for the above, an ethylenically unsaturated group-containing acrylic resin (2') was obtained in the same manner as in Production Example 2.

The obtained ethylenically unsaturated group-containing acrylic resin (2') has a solid content of 31.4% by weight and a viscosity of 1,500 mPa·s/25°C, and the esterification rate calculated from the results of ¹³ C-NMR measurement is 8.4% (reaction rate is 100%). , and the content of the ethylenically unsaturated group was 20 mmol/100 g.

<Production Example 6>

80 mol% of 2HEA with respect to 100 mol% of the carboxy-containing monomer in the carboxy-containing acrylic resin (α'-1) and the carboxy-containing acrylic resin (α'-1) prepared above, 0.50 mol% of magnesium hydroxide and 0.50 mol% of lithium hydroxide were added to 2HEA, respectively, and the temperature was raised to 60°C while stirring.

Subsequently, a 50% toluene solution of di-t-butyl dicarbonate (I-1) in the same mol as the 2HEA charged was added dropwise over 6 hours. Immediately after the start of dripping, a gradual increase in viscosity was observed, and since continuation of the reaction became difficult, the reaction was stopped halfway.

The presence or absence of carbamate groups and the content of ethylenically unsaturated groups in the ethylenically unsaturated group-containing acrylic resins obtained in Production Examples 1 to 6 are shown in Table 1 below.

<Example 1>

With respect to 100 parts of the solid content of the ethylenically unsaturated group-containing acrylic resin (1) obtained above, an isocyanate-based crosslinking agent (“Coronate L-55E” manufactured by Nippon Polyurethane Co., Ltd.) was added to 1.0 parts and a photopolymerization initiator (“Irgacure 184” manufactured by BASF Corporation). ) was mixed with 3.00 parts to prepare an active energy ray-curable pressure-sensitive adhesive composition. In addition, the composition of Example 1 is shown in Table 2 below.

<Examples 2 and 3 and Comparative Examples 1 and 2>

In Example 1, the type of ethylenically unsaturated group-containing acrylic resin, the isocyanate-based crosslinking agent and the photopolymerization initiator were blended and mixed according to Table 2, Examples 2 and 3 and Comparative Examples 1 and 2 Active energy ray-curable pressure-sensitive adhesives composition was prepared.

The adhesive composition of Examples 1 to 3 and Comparative Examples 1 and 2 is applied onto a polyimide film (film thickness: 50 µm) ("Kapton 200H" manufactured by Toray DuPont) to a thickness after drying of 25 µm, and dried. Then, it was attached to a 38 μm separator ("SP-PET3801-BU" manufactured by Mitsui Chemicals Higashicello Co., Ltd.), and aged at 40°C for 3 days to prepare an adhesive sheet.

About the obtained adhesive sheet, the following evaluation was performed. The evaluation results are shown in Table 2 below.

<Adhesive strength before irradiation with active energy rays>

A test piece of 25 mm × 100 mm was prepared from the adhesive sheet obtained above, and after peeling off the separator, a rubber roller having a weight of 2 kg was reciprocated twice in an atmosphere of 23 ° C. and 50% RH, applied under pressure, and 30 After leaving still for a minute, the 180-degree peel strength (N/25 mm) was measured at a peel speed of 300 mm/min. The evaluation criteria are as follows.

(Evaluation standard)

◎・・・6.0N/25mm or more

○ 3.0 N/25 mm or more, less than 6.0 N/25 mm

×...less than 3.0N/25mm

<Adhesive strength after active energy ray irradiation>

A test piece of 25 mm × 100 mm was prepared from the adhesive sheet obtained above, and after peeling off the separator, a rubber roller having a weight of 2 kg was reciprocated twice in an atmosphere of 23 ° C. and 50% RH, applied under pressure, and 30 After standing still for a minute, UV irradiation (accumulated irradiation amount 250 mJ/cm 2 ) was applied from the glass plate side using one 80 W high-pressure mercury lamp, and immediately the 180 degree peel strength (N/25 mm) was measured at a peel rate of 300 mm/min. . The evaluation criteria are as follows.

(Evaluation standard)

◎... Less than 0.1N/25mm

○ 0.1 N/25 mm or more, 1 N/25 mm or less

×...larger than 1N/25mm

＜Adhesive strength after heating and irradiation with active energy rays (150℃)＞

A test piece of 25 mm × 100 mm was prepared from the adhesive sheet obtained above, and after peeling off the separator, a rubber roller having a weight of 2 kg was reciprocated twice in an atmosphere of 23 ° C. and 50% RH, applied under pressure, and heated at 150 ° C. It was put into one oven jet dryer for 1 hour. After taking it out of the dryer, and cooling in an atmosphere of 23°C and 50% RH for 30 minutes, UV irradiation (accumulated irradiation amount: 250 mJ/cm 2 ) was applied from the glass plate side again using one 80 W high-pressure mercury lamp, and immediately the peeling rate was 300 mm. The 180 degree peel strength (N/25 mm) was measured at /min. Moreover, the adherend after peeling was visually confirmed and stain resistance was evaluated. The evaluation criteria are as follows.

(Evaluation criteria: adhesion)

◎... Less than 0.5N/25mm

○ 0.5 N/25 mm or more, 1.0 N/25 mm or less

×...greater than 1.0N/25mm

(Evaluation criteria: contamination resistance)

◎···There is residual adhesive

○···A little residual glue

×···Residual adhesive on the front

<Adhesive strength after heating/irradiation with active energy rays (200°C)>

A test piece of 25 mm × 100 mm was prepared from the adhesive sheet obtained above, and after peeling off the separator, a rubber roller having a weight of 2 kg was reciprocated twice in an atmosphere of 23 ° C. and 50% RH, applied under pressure, and heated at 200 ° C. It was put into an oven jet dryer for 1 hour. After taking it out of the dryer and cooling it in an atmosphere of 23°C and 50% RH for 30 minutes, UV irradiation (integrated irradiation amount 250 mJ/cm 2 ) was performed from the glass plate side using one 80 W high-pressure mercury lamp again, and the peeling rate was 300 mm/min. 180 degree peel strength (N/25 mm) was measured. Moreover, the adherend after peeling was visually confirmed and stain resistance was evaluated. The evaluation criteria are as follows.

(Evaluation criteria: adhesion)

◎... Less than 0.5N/25mm

○ 0.5 N/25 mm or more, 2.0 N/25 mm or less

×...larger than 2.0N/25mm

(Evaluation criteria: contamination resistance)

◎···No residual adhesive

○···A little residual glue

×···Residual adhesive on the front

As can be seen from Table 2 above, the products of Examples 1 to 3 containing the ethylenically unsaturated group-containing acrylic resin having a specific ethylenically unsaturated group-containing structural site in a predetermined amount in the side chain have adhesive strength before active energy ray irradiation and active energy ray irradiation It was excellent in peelability after.

In addition, the products of Examples 1 to 3 were excellent in stain resistance with reduced adhesive strength by irradiation with active energy rays even after heating at 150°C and 200°C.

On the other hand, in Comparative Example 1 using an acrylic resin having no specific ethylenically unsaturated group-containing structural site, the adhesive force before active energy ray irradiation was high and the adhesive force after active energy ray irradiation was low, but the adhesive force after heating was high and stain resistance Saints were falling. In addition, the product of Comparative Example 2 using an acrylic resin not containing a specific ethylenically unsaturated group-containing structural site in a predetermined amount had high adhesive strength after irradiation with active energy rays and high adhesive strength after heating, and was poor in peelability.

Although the specific form in this invention was shown in the said Example, the said Example is only a mere illustration and is not interpreted limitedly. Various modifications obvious to those skilled in the art are intended to fall within the scope of the present invention.

The pressure-sensitive adhesive composition of the present invention can be suitably used as a pressure-sensitive adhesive composition for pressure-sensitive adhesive films for temporary surface protection when processing electronic substrates, semiconductor wafers, processed glass products, metal plates, plastic plates, and the like.

Claims (17)

Ethylenically unsaturated containing an ethylenically unsaturated group-containing structural moiety represented by the following formula (1) in the side chain of the acrylic resin and having an ethylenically unsaturated group content of 25 to 500 mmol/100 g relative to the ethylenically unsaturated group-containing acrylic resin A pressure-sensitive adhesive composition comprising a group-containing acrylic resin.
[Formula 1]

[R ¹ is a substituent containing an ethylenically unsaturated group,
R ² is an organic group containing at least one selected from C, O, N and S
(However, excluding carbamate groups), and X is O or NH.] The method of claim 1,
The pressure-sensitive adhesive composition characterized in that the acrylic resin containing an ethylenically unsaturated group contains a hydroxyl group. According to claim 1 or 2,
An adhesive composition characterized by further containing a crosslinking agent. According to claim 1 or 2,
An adhesive composition characterized by further containing a photopolymerization initiator. According to claim 1 or 2,
The ethylenically unsaturated group-containing acrylic resin is formed by reacting a hydroxyl group-containing acrylic resin (α) and an ethylenically unsaturated group-containing carboxylic acid (β) in the presence of a compound (I) represented by the following formula (2) adhesive composition.
[Formula 2]

[Here, R ³ and R ⁴ represent a hydrocarbon group having 1 to 20 carbon atoms.] According to claim 1 or 2,
The ethylenically unsaturated group-containing acrylic resin is formed by an esterification reaction between a hydroxyl group-containing acrylic resin (α) and (meth)acrylic acid anhydride (γ). A pressure-sensitive adhesive sheet characterized in that the pressure-sensitive adhesive composition according to claim 1 or 2 has a crosslinked pressure-sensitive adhesive layer. The method of claim 7,
A pressure-sensitive adhesive sheet characterized in that the pressure-sensitive adhesive layer is cured by irradiation with active energy rays and becomes peelable. The method of claim 7,
A pressure-sensitive adhesive sheet characterized in that it is subjected to a heating step at 150°C or higher after the pressure-sensitive adhesive sheet is applied to the surface of an adherend. A method for producing an ethylenically unsaturated group-containing acrylic resin, characterized by reacting a hydroxyl group-containing acrylic resin (α) with an ethylenically unsaturated group-containing carboxylic acid (β) in the presence of a compound (I) represented by the following formula (2).
[Formula 2]

[Here, R ³ and R ⁴ represent a hydrocarbon group having 1 to 20 carbon atoms.] The method of claim 10,
When the hydroxyl group-containing acrylic resin (α) and the ethylenically unsaturated group-containing carboxylic acid (β) are reacted in the presence of the compound (I) represented by the formula (2), at least one magnesium compound and at least one alkali metal A method for producing an ethylenically unsaturated group-containing acrylic resin characterized by reacting in the presence of a compound. The method of claim 11,
Method for producing an ethylenically unsaturated group-containing acrylic resin, characterized in that the alkali metal constituting the alkali metal compound is lithium. According to any one of claims 10 to 12,
A method for producing an ethylenically unsaturated group-containing acrylic resin, wherein the compound (I) represented by the formula (2) is di-t-butyl dicarbonate. According to any one of claims 11 to 12,
A method for producing an ethylenically unsaturated group-containing acrylic resin characterized by reacting the ethylenically unsaturated group-containing carboxylic acid (β) in the presence of 0.001 to 1000 mol% of the magnesium compound and 0.001 to 1000 mol% of the alkali metal compound. According to any one of claims 10 to 12,
A method for producing an ethylenically unsaturated group-containing acrylic resin, characterized in that the content of the hydroxyl group-containing monomer (a1) constituting the hydroxyl group-containing acrylic resin (α) is 0.1 to 50% by weight with respect to the entire polymerization component. According to any one of claims 10 to 12,
The content of the ethylenically unsaturated group of the ethylenically unsaturated group-containing acrylic resin is 25 to 500 mmol / 100 g relative to the ethylenically unsaturated group-containing acrylic resin. According to any one of claims 10 to 12,
The method for producing an ethylenically unsaturated group-containing acrylic resin, characterized in that the acid value of the hydroxyl group-containing acrylic resin (α) is 10 mgKOH / g or less.