JPH06322338A - Releasable adhesive and adhesive member using the same - Google Patents

Abstract

PURPOSE:To provide a releasable type emulsion adhesive extremely not leaving stain substances by releasing without requiring an extraction treatment using a solvent, and to provide an adhesive member using the same adhesive. CONSTITUTION:The releasable adhesive comprises an emulsion and, if necessary, a cross-linking agent to form an adhesive layer having a THF-insoluble content of >= 90% and a degree of swelling of >=10 times in THF. The emulsion contains an acrylic polymer which may be a cross-linked one and is formed by gradually emulsion-copolymerizing at least an acrylic acid 4-12C alkyl ester, a nonionic surfactant having a copolymerizable unsaturated group, and a functional or cross-linkable monomer in the presence of a small amount of a water- soluble orgnaic radical polymerization initiator. An adhesive member having the layer of the adhesive on a support substrate. The adhesive gives an adhesive layer little in the content of free substances, and excellent water resistance, adherend deterioration prevention, adhesive balance between adhesiveness and releasability, etc.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a re-peelable pressure-sensitive adhesive which is suitable for surface protection of various articles such as IC wafers, since contaminants such as glue components remaining on the adherend during re-peeling are extremely small.
And an adhesive member thereof.

[0002]

BACKGROUND OF THE INVENTION It is used for the purpose of surface protection such as temporary attachment to adherends made of various articles such as metal plates, decorative plates, glass plates, etc. to prevent damage, adhesion of dust, alteration such as oxidation, etc. In the case of an adhesive member that requires re-peeling, while maintaining sufficient adhesive strength that does not cause peeling during temporary attachment, contaminants such as glue components may not remain on the adherend during re-peeling. It is strongly desired from the standpoint of omitting a cleaning step after peeling.

In particular, in the case of an IC wafer having a circuit pattern formed on a semiconductor wafer, a high degree of clarification is required because residual contaminants cause serious defects such as interference with circuit functions. Further, in the IC wafer, an adhesive member is used even at the time of polishing the back surface or cutting into chips and the like, and therefore an adhesive force sufficient to adhere to the wafer is required in order to prevent invasion of cleaning water.

[0004]

2. Description of the Related Art Conventionally, as the pressure-sensitive adhesive member suitable for the above-mentioned re-peeling use, a pressure-sensitive adhesive layer is subjected to an extraction treatment with a solvent to remove low molecular weight polymers and other substances, and free components such as surfactants. Was known. However, in that case, there is a problem that the production efficiency is poor because it is necessary to completely extract and remove even the inside of the adhesive layer. In the incomplete extraction treatment in which the free components remain inside due to the treatment of the surface portion, etc., the residual free components are precipitated and accumulated on the surface, and rather, the remarkable residual contamination is more likely to occur than the untreated product.

On the other hand, one using an emulsion type adhesive has also been proposed. In this case, however, the surfactant remains as a free component in the pressure-sensitive adhesive layer and becomes a contaminant during re-peeling, and the step is required even if it is easily washed and removed. Also, an inorganic salt-based polymerization initiator such as ammonium persulfate for emulsion polymerization becomes a contaminant during re-peeling, and even if a small amount remains, it will cause a defect in the IC circuit, and even in the case of adherends such as metal plates. It becomes a particularly inconvenient pollutant such as alteration.

Further, as in the case of the emulsion system,
If a large amount of water-soluble free components remain in the pressure-sensitive adhesive layer, the water resistance of the adhesive force will be reduced, which will cause invasion of cleaning water during the back surface polishing of the IC wafer, and the peeling problem will easily occur.

[0007]

The object of the present invention is to develop an emulsion-based removable pressure-sensitive adhesive in which the amount of contaminants remaining after re-peeling is extremely small even if extraction treatment with a solvent is not performed, and an adhesive member thereof. To do.

[0008]

Means for Solving the Problems The present invention relates to an acrylic acid-based alkyl ester having an alkyl group with 4 to 12 carbon atoms,
An emulsion containing a nonionic surfactant having a copolymerizable unsaturated group and an acrylic polymer formed by gently emulsion-copolymerizing a small amount of a water-soluble organic radical polymerization initiator using at least a functional monomer. , TH
A removable pressure-sensitive adhesive comprising a cross-linking agent so that the F insoluble content is 90% or more and the degree of swelling with THF is 10 times or more.

In the present invention, the alkyl group has 4 to 4 carbon atoms.
12 Acrylic alkyl ester, a nonionic surfactant having a copolymerizable unsaturated group, and a crosslinkable monomer are used to form an emulsion copolymer with a small amount of a water-soluble organic radical polymerization initiator. TH,
A removable pressure-sensitive adhesive comprising an emulsion containing a crosslinked acrylic polymer having an F insoluble content of 90% or more and a swelling degree with THF of 10 times or more.

Further, in the present invention, T-insoluble matter containing 90% or more of THF-insoluble matter, which comprises the above-mentioned removable adhesive on a supporting substrate.
It is intended to provide an adhesive member having an adhesive layer having a swelling degree by HF of 10 times or more.

[0011]

[Function] An acrylic acid alkyl ester having an alkyl group having 4 to 12 carbon atoms is used as a main component, and a nonionic one having a copolymerizable unsaturated group is used as a surfactant capable of emulsion polymerization. As a result, the surfactant can be incorporated into the acrylic polymer as a copolymerization component, and its free substance can be avoided.
It can be made to have excellent adhesive properties such as adhesive adhesion and removability.

Further, by slowly advancing the polymerization reaction using a small amount of a water-soluble organic radical polymerization initiator, it is possible to suppress the formation of a low molecular weight polymer which easily becomes a free substance, for example, a polymer having a weight average molecular weight of 10,000 or less. ,
It is also possible to prevent the initiator itself from remaining as a free substance,
In addition, the organic type initiator has less influence on the adherend such as alterations than the inorganic salt type. Furthermore, the final crosslinked structure can increase the molecular weight and further reduce the amount of polymer that becomes a free substance.

In addition, by forming a pressure-sensitive adhesive layer having a THF (tetrahydrofuran) insoluble content of 90% or more and a swelling degree with THF of 10 times or more, adhesion adhesion to an adherend and reduction of free substances And can be well balanced. Therefore, according to the above, it is possible to obtain a pressure-sensitive adhesive which has a small amount of free substances and is particularly excellent in non-staining property at the time of re-peeling, without the need for extraction treatment.

[0014]

Examples of constituent elements of the invention The removable adhesive of the present invention is
It is based on an emulsion containing an acrylic polymer formed by an emulsion copolymerization method, and the acrylic polymer is an acrylic acid alkyl ester having an alkyl group with 4 to 12 carbon atoms and a copolymerizable unsaturated group. Is a nonionic surfactant having at least one component.

Examples of the acrylic acid type alkyl ester include butyl group, isobutyl group, amyl group, isoamyl group, 2-ethylhexyl group, octyl group, isooctyl group, nonyl group, isononyl group, decyl group and dodecyl group. Acrylic acid or methacrylic acid ester having an alkyl group having 4 to 12 carbon atoms is used.

The acrylic acid type alkyl ester having an alkyl group having 4 to 12 carbon atoms may be used alone or in combination of two or more as a main component monomer of the desired acrylic polymer. The content is usually 50% by weight or more, especially 70% by weight or more.

Examples of the nonionic surfactant having a copolymerizable unsaturated group include those represented by the general formula: (However, R is hydrogen or an alkyl group, n is 10 to 70.) A polyoxyethylene alkylphenyl ether represented by a radical-polymerizable propenyl group introduced into a phenyl group as a hydrophobic group is can give.

The nonionic surfactant is incorporated into the target acrylic polymer as a copolymerization component through the copolymerizable unsaturated group, and is used as an emulsifier for emulsion polymerization in the present invention. And HLB is 1
Those having 4 to 18 can be preferably used. The amount used is appropriately determined depending on the emulsified state and the like, but generally 0.2 to 10% by weight, and particularly 1 to 5% by weight of the total copolymerization components are used.

In the present invention, the purpose is finally to form a crosslinked acrylic polymer, but various methods can be selected for the formation. One of them is a method in which a functional monomer having a functional group that reacts with a cross-linking agent is copolymerized with an acrylic polymer and cross-linked by a separately added cross-linking agent. The other method is a method in which a desired crosslinked acrylic polymer is directly prepared by copolymerization in the presence of a self-crosslinking crosslinkable monomer. In the present invention, the above-mentioned respective methods may be used in combination to finally form the desired crosslinked acrylic polymer.

As the above-mentioned functional monomer, a monomer having an appropriate functional group which reacts with the crosslinking agent used in combination is used. Preferably, a monomer containing a carboxyl group is used. Examples thereof include acrylic acid, methacrylic acid, maleic anhydride, itaconic acid, crotonic acid and the like.

Examples of other monomers that can be used as the functional monomer include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl-containing monomers such as hydroxybutyl methacrylate, diaminoethyl acrylate, and the like. Amino group-containing monomer such as diaminoethyl methacrylate, acrylamide, methacrylamide,
Examples thereof include amide group-containing monomers such as N, N-dimethylacrylamide and N, N-dimethylmethacrylamide.

The amount of the functional monomer used is appropriately determined depending on the functional group and the kind of the crosslinking agent used in combination. Generally, 1% by weight or less of all copolymerization components, especially 0.001-
0.5% by weight is used. If the amount used exceeds 1% by weight, an excessive amount of the acrylic polymer is introduced as a copolymerization component, and when cross-linked with a cross-linking agent, an excessively cross-linked acrylic polymer may be formed, resulting in poor adhesive strength.

Since the inclusion of a carboxyl group tends to cause deterioration of an adherend made of a metal or the like, in the case of a carboxyl group-containing acrylic polymer, an adherend made of a plastic or the like which is hard to be deteriorated by a carboxyl group or a deterioration Is generally applied to the formation of an adhesive member used for an adherend which does not cause a problem, but in that case also, it is preferable that the content of the carboxyl group unit is adjusted to 5 mol% or less.

On the other hand, the cross-linkable monomer is 2
Any suitable monomer having one or more bonds may be used.
The crosslinkable monomer that can be preferably used is one that does not contain a carboxyl group that tends to cause deterioration of the adherend.

Examples of crosslinkable monomers that can be preferably used are ethylene glycol diacrylate, neopentyl diacrylate, hexanediol diacrylate,
Examples include propylene glycol diacrylate, trimethylol propane triacrylate, tetramethylol methane triacrylate, dipentaerythritol hexaacrylate, glycidyl acrylate, or polyfunctional acrylic acid esters such as those obtained by substituting methacrylic acid for those acrylic acid components. To be

Further, N-methylol acrylamide, N
An acrylamide compound such as -methoxymethyl acrylamide, N-butoxymethyl acrylamide, or a compound obtained by substituting the acrylamide component thereof with methacrylamide is also preferably used as the crosslinkable monomer.

Furthermore, propyltrimethoxysilane acrylate, propyldimethoxysilane acrylate, propyltriethoxysilane acrylate, or polyfunctional alkoxysilanes such as those obtained by substituting methacrylic acid for these acrylic acid components, and other divinylbenzene, etc. It can be preferably used as a crosslinkable monomer.

In the case of a method of directly preparing a crosslinked acrylic polymer by copolymerizing a crosslinkable monomer, the amount of the crosslinkable monomer used is 0.01 to 5% by weight based on the total amount of the copolymerized components.
Above all, 0.02 to 3% by weight is used. When the amount used is less than 0.01% by weight, a low-molecular-weight polymer is likely to be formed due to insufficient crosslinking, and when it exceeds 5% by weight, an acrylic polymer with excessive crosslinking is formed, resulting in poor adhesive strength. There is.

In the present invention, other modifying monomers that may be optionally used for the purpose of improving the adhesive strength when forming an acrylic polymer include, for example, carbon such as methyl group, ethyl group and propyl group. Examples thereof include acrylic acid or methacrylic acid esters having an alkyl group of 3 or less, acrylonitrile, methacrylonitrile, styrene or a derivative thereof, vinyl acetate, N-vinylpyrrolidone, and methoxyethyl acrylate.

In the present invention, an emulsion of an acrylic polymer prepared by an emulsion polymerization method with a small amount of a water-soluble organic radical polymerization initiator is used for forming a pressure-sensitive adhesive.
Examples of the water-soluble organic radical polymerization initiator include water-soluble organic peroxides and azo compounds, and the latter can be preferably used when used for an easily corrosive adherend.

Examples of water-soluble organic peroxides include t-
Butyl peroxy maleic acid, t-butyl hydroperoxide, hydrogen peroxide and the like can be mentioned, and an appropriate reducing agent can also be used in combination.

Examples of water-soluble azo compounds include 2,
2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2'-azobis (2-
Methylpropionamide) dihydrate, 2,2'-
Examples thereof include azobis (N, N'-dimethyleneisobutylamidine), 2- (carbamoylazo) isobutyronitrile and the like.

The amount of the water-soluble organic radical polymerization initiator used is preferably as small as possible from the viewpoint of preventing the formation of a low molecular weight polymer which is likely to become a free component, and 0.005 to 0. 1 mol% is preferred. In this case, even if a polymerization initiator is added all at once, the reaction proceeds slowly and stable polymerization is likely to occur, and the resulting acrylic polymer has good properties.

The emulsion polymerization treatment may be carried out by an appropriate method. As an example, a mixed solution of a copolymerization component such as a raw material monomer is added to a predetermined amount of water such as deionized water in a reaction vessel to be mixed and emulsified, the reaction vessel is replaced with nitrogen, and a predetermined reaction temperature is set under stirring. Examples of the method include a method of preparing a desired emulsion containing an acrylic polymer by heating to complete the emulsion polymerization.

In the above, the water-soluble organic radical polymerization initiator may be added at the time of mixing and emulsifying the copolymerization components or at the time of heating to the reaction temperature. In addition, the addition may be performed all at once or may be performed in divided portions.

Further, an alcoholic compound having a boiling point of 150 ° C. or lower may be added. Such a compound functions as a polymerization stabilizer, a coatability improving agent, and the like. An appropriate amount of addition is 30% by weight or less based on the total amount of the copolymerization components. Specific examples of the alcoholic compound include methanol, n-propanol, n-butanol, t-butanol, methoxyethanol and the like.

The polymerization temperature is generally 20 to 80 ° C. In the present invention, it is preferable to carry out the polymerization at a temperature as low as possible from the viewpoint of increasing the polymerization degree and preventing the formation of a low molecular weight polymer. In the case of a water-soluble organic radical polymerization initiator having a 10-hour half-life temperature of 40 to 90 ° C, a method of performing a polymerization treatment at a temperature of 30 to 50 ° C is particularly preferable, but not limited to the above.

A part of the mixed solution of the copolymerization components is added to water to emulsify it, and the mixture is subjected to a polymerization treatment to produce fine polymer particles, and the mixed solution remaining as seed particles is gradually added. A polymerization method (seed feed method) in which the particle size is grown by the above method can be preferably applied because it is easy to obtain a polymer having a uniform particle size.

In order to form a pressure-sensitive adhesive layer having a THF insoluble content of 90% or more and a swelling degree with THF of 10 times or more, the re-peelable pressure-sensitive adhesive of the present invention may contain a crosslinking agent, if necessary, and may be an acrylic resin. The polymer is subjected to a crosslinking treatment. Cross-linking by blending a cross-linking agent can be used not only for adjusting the above-mentioned adhesive properties, but also for improving anchorage or adhesion to a supporting base material forming an adhesive member.

Examples of the cross-linking agent include water-soluble polyfunctional epoxy compounds, aqueous dispersions of polyfunctional epoxy compounds,
A water-soluble melamine compound, an aqueous dispersion of a melamine compound, a water-soluble polyfunctional isocyanate compound, an aqueous dispersion of a polyfunctional isocyanate compound, and the like can be preferably used.

The amount of the cross-linking agent added is 90% of THF insoluble matter.
As described above, the degree of swelling with THF is appropriately determined according to the acrylic polymer to be crosslinked for the purpose of forming a pressure-sensitive adhesive layer having a fold or more 10 times. Generally, the acrylic polymer having a weight average molecular weight of 50,000 to 3,000,000 is formed by crosslinking, and the solid content of the emulsion containing the acrylic polymer is adjusted so that the crosslinking agent does not remain as a free component. 0.001 to 5 parts by weight, and especially 0.01 to 0.5 parts by weight, are used per 100 parts by weight.

The pressure-sensitive adhesive member of the present invention has a pressure-sensitive adhesive layer having a thickness of about 5 to 500 μm provided on one or both sides of a supporting substrate. As the supporting base material, a suitable plastic film such as polyvinyl chloride, ethylene / vinyl alcohol, ethylene / vinyl acetate, polyester, or a thin leaf made of paper, woven fabric, non-woven fabric, metal foil or the like is generally used.

The attachment of the pressure-sensitive adhesive layer on the supporting base material requires direct coating of the pressure-sensitive adhesive on the supporting base material by an appropriate method such as a casting method or a coating method, and then a drying treatment or a crosslinking treatment. A method in which a pressure-sensitive adhesive layer having a THF-insoluble content of 90% or more and a swelling degree with THF of 10 times or more is applied, or a separator, for example, a thin leaf surface-treated with a release agent,
It can be carried out by an appropriate method such as a method of transferring a pressure-sensitive adhesive layer formed according to the above on a weakly adhesive film such as polypropylene or polyester onto a supporting substrate.
When it is desired to improve the adhesion between the supporting base material and the pressure-sensitive adhesive layer, the supporting base material may be subjected to necessary treatment such as corona treatment or surface treatment with an undercoating agent.

When the THF insoluble content in the pressure-sensitive adhesive layer is less than 90%, the content of free components is large and the adherend is liable to be contaminated during re-peeling. If the pressure-sensitive adhesive layer has a degree of swelling with THF of less than 10 times, it may be too hard and the adhesion to the adherend may be poor. This lack of adhesion causes a gap in the stepped portion on the circuit pattern surface of the IC wafer to cause intrusion of cleaning water and the like, which causes contamination by cleaning contaminated water and the like. Incidentally, it is a general tendency that the degree of swelling decreases as the amount of THF-insoluble matter increases.

The above-mentioned THF-insoluble matter was prepared by applying a pressure-sensitive adhesive on a glass plate to a thickness of 100 μm, drying the pressure-sensitive adhesive layer at 105 ° C. for 5 minutes, scraping it with a knife and immersing it in THF at 20 ° C. for 1 week. , THF insoluble matter is separated and collected, the weight (B) immediately after drying is measured, and the weight (A) before immersion in THF is used to calculate by the following formula. THF insoluble matter (crosslinking ratio:%) = B / A × 100

The degree of swelling is determined by measuring the dry weight (B) of the THF-insoluble matter and the T-insoluble matter of 20 ° C. before drying.
It is calculated by the following formula using the absorption weight (C) of THF in one immersed in HF for one week. Swelling degree = (B + C) / B

The pressure-sensitive adhesive member of the present invention is used for the purpose of surface protection for preventing damage, adhesion of dust, alteration such as oxidation, and the like.
It can be preferably used for applications in which re-peeling is indispensable after temporary attachment, such as the purpose of fixing and holding the back surface of a C wafer or chipping by cutting. As the adherend, various articles such as a plate and a decorative plate made of, for example, a metal, a semiconductor such as silicon, a ceramic such as glass, or a plastic can be used.

[0048]

EFFECTS OF THE INVENTION According to the present invention, the content of free substances is small due to the copolymerization of surfactants, the formation of low molecular weight polymers and the suppression of the remaining polymerization initiator, and the extraction treatment with a solvent is not required. Also, it is possible to obtain an emulsion-based removable pressure-sensitive adhesive or a pressure-sensitive adhesive member thereof, in which residual contaminants are extremely small during re-peeling. Further, the pressure-sensitive adhesive layer is also excellent in water resistance, property of preventing deterioration of adherend, and balance of adhesive strength between adhesive adhesion and removability.

[0049]

【Example】

Example 1 A container equipped with a thermometer, a reflux condenser, a nitrogen inlet, and a stirrer was charged with 225 parts of deionized water (parts by weight, hereinafter the same), and 212.5 parts of butyl acrylate and 25 parts of acrylonitrile, Hydroxyethyl acrylate 12.5
Parts, trimethylolpropane triacrylate 0.05
Part and HLB of 17 are propenyl group-introduced polyoxyethylene alkylphenyl ethers (compounds of the above general formula,
The same applies hereafter) The whole amount of the mixed solution of 8 parts was added, the atmosphere was replaced with nitrogen, the mixture was emulsified with stirring, and the temperature was raised to 40 ° C. to obtain 2,2′-
Azobis (N, N'-dimethyleneisobutylamidine)
0.12 parts was added, and the mixture was kept at 40 ° C for 6 hours, then 45
Hold at ℃ for 3 hours to react, let cool to room temperature, 250
The emulsion was filtered through a nylon mesh cloth to obtain an acrylic polymer-containing emulsion. To 100 parts of the emulsion was added water-soluble melamine (0.5 part) and the mixture was stirred to obtain a removable pressure-sensitive adhesive.

Next, the re-peelable pressure-sensitive adhesive was applied onto a biaxially stretched polyester film having a thickness of 38 μm by a bar coater and dried at 80 ° C. for 20 minutes to attach a pressure-sensitive adhesive layer having a thickness of 20 μm. The adhesive layer was attached to a corona-treated surface of an ethylene / vinyl acetate film having a thickness of 150 μm and cured at 50 ° C. for 7 days to obtain an adhesive member.

Example 2 To 100 parts of the emulsion obtained in Example 1 was added 0.4 part of an aqueous dispersion (emulsion) solution of a polyfunctional compound of hexamethylene diisocyanate (solid content 25% by weight), and the mixture was stirred to be removable. An adhesive was obtained. Next, the re-peelable pressure-sensitive adhesive is applied to a thickness of
It is coated with a bar coater on the corona-treated surface of 50 μm ethylene / vinyl acetate film, dried at 80 ° C. for 20 minutes and attached with a 20 μm thick adhesive layer, and cured at 50 ° C. for 7 days to obtain an adhesive member. It was

Example 3 217.5 parts butyl acrylate, 2 methyl methacrylate
0 parts, methyl acrylate 12.5 parts, Nn-butoxymethyl acrylamide 7 parts, HLB 17 propenyl group-introduced polyoxyethylene alkylphenyl ether 8
Parts and 20 parts of n-propyl alcohol were used for polymerization according to Example 1 to obtain a removable pressure-sensitive adhesive composed of a crosslinked acrylic polymer-containing emulsion, which was used in Example 1. A corresponding adhesive member was obtained.

Example 4 A container equipped with a thermometer, a reflux condenser, a nitrogen inlet and a stirrer was charged with 225 parts of deionized water, and 195 parts of butyl acrylate and 30 parts of 2-methoxyethyl acrylate were added to the container.
25 parts of N-vinylpyrrolidone, 0.5 part of γ-methacryloxypropyltrimethoxysilane, 8 parts of propoxy group-introduced polyoxyethylene alkylphenyl ether having HLB of 17, and a mixed solution of 20 parts of methanol and 10 parts of t-butyl alcohol. Was replaced with nitrogen, mixed and emulsified under stirring, and then heated to 55 ° C. to obtain 0.1 part of 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide]. Was added, and the mixture was kept at 55 ° C for 6 hours, then kept at 65 ° C for 3 hours to react, cooled to room temperature, filtered through a 250-mesh nylon cloth, and re-peelable adhesive composed of emulsion containing cross-linked acrylic polymer. An agent was obtained, and using this, an adhesive member was obtained according to Example 1.

Example 5 A container equipped with a thermometer, a reflux condenser, a nitrogen inlet and a stirrer was charged with 225 parts of deionized water, and 205 parts of butyl acrylate, 38 parts of methyl acrylate and 2 parts of acrylic acid were added to the container.
-Hydroxyethyl 8 parts, acrylic acid 0.5 parts, HLB
18 parts of a propenyl group-introduced polyoxyethylene alkylphenyl ether (5 parts) and 35 parts of methanol (35 parts) were added to replace the mixture with nitrogen, and the mixture was mixed and emulsified with stirring. 2,2′-azobis (N, N′-dimethyleneisobutylamidine) was added to
After keeping at 0 ° C. for 6 hours, 0.01 part was additionally added and kept at 45 ° C. for 3 hours to react, cooled to room temperature and filtered through a 250 mesh nylon cloth to obtain an emulsion containing an acrylic polymer. To 100 parts, 0.1 parts of 25 wt% ammonia water and 0.01 parts of water-soluble polyfunctional epoxy compound were added and stirred to obtain a removable pressure-sensitive adhesive, which was used to prepare an adhesive member according to Example 2. Obtained.

Example 6 A container equipped with a thermometer, a reflux condenser, a nitrogen inlet and a stirrer was charged with 225 parts of deionized water, 0.2 part of L-ascorbic acid was added, and butyl acrylate 212. 5
Parts, 25 parts of acrylonitrile, 12.5 parts of hydroxyethyl acrylate, 0.05 parts of trimethylolpropane triacrylate and 8 parts of a propenyl group-introduced polyoxyethylene alkylphenyl ether having an HLB of 17 are added to replace the mixture with nitrogen. Then, after mixing and emulsifying with stirring, the temperature was raised to 40 ° C and maintained, while 50 parts of deionized water in which 0.5 part of t-butyl hydroperoxide was dissolved was added dropwise over 5 hours, and then 45 ° C. The mixture is allowed to react for 3 hours, cooled to room temperature, filtered through a 250-mesh nylon cloth to obtain an acrylic polymer-containing emulsion, to which 100 parts of water-soluble melamine is added, stirred and re-mixed. A peelable pressure-sensitive adhesive was obtained, and using it, a pressure-sensitive adhesive member was obtained according to Example 1.

Comparative Example 1 A pressure-sensitive adhesive and its pressure-sensitive adhesive member were obtained in the same manner as in Example 1 except that the propenyl group-introduced polyoxyethylene alkylphenyl ether was replaced with a propenyl group-free one.

Comparative Example 2 2,2'-Azobis (N, N'-dimethyleneisobutylamidine) was added in an amount of 0.6 part, and 60 parts were added.
A pressure-sensitive adhesive and its pressure-sensitive adhesive member were obtained in the same manner as in Example 1 except that the temperature was maintained at 70 ° C. for 4 hours and then at 70 ° C. for 2 hours.

Comparative Example 3 An adhesive and its adhesive member were obtained in the same manner as in Comparative Example 2 except that 0.5 part of ammonium persulfate was used as a polymerization initiator.

Comparative Example 4 An adhesive and its adhesive member were obtained in the same manner as in Example 1 except that the amount of trimethylolpropane triacrylate used was 1.2 parts.

Evaluation Test The following characteristics of the adhesive members obtained in Examples and Comparative Examples were examined. Adhesive strength Adhesive material with a width of 20 mm is stainless steel plate (SUS 304 BA finish)
1kg of rubber roller was reciprocated once and pressed to measure the force required for peeling (180 degree peeling, peeling speed 300mm /
Minutes).

Water resistance A 0.5 mm thick stainless steel plate (SUS 304 BA finish) having a diameter of 10 cm was adhered to a PFT-based adhesive tape having a thickness of about 50 μm with a distance of 3 mm from the periphery. From the top, adhere the test adhesive member in the same area as the disk, and after 30 minutes have passed, dip it in distilled water at 23 ° C. for 24 hours and take it out.
The peeling state of the adhesive member at the periphery was examined and evaluated according to the following criteria. ◯: No peeling at all Δ: Peeling at part partially ×: Peeling at half or more of the peripheral edge

Copper plate corrosiveness 2 cm wide, on a copper plate surface polished with No. 280 sandpaper.
After bonding a 12 cm long adhesive member, 50 ° C, humidity 10
0% R. H. After leaving it for 24 hours, it was taken out, cooled to room temperature, the adhesive member was peeled off, and the degree of discoloration was examined and evaluated according to the following criteria. ◎: brown (no change) ○: dark brown △: greenish ×: green

Number of Particles An adhesive member was adhered to a silicon wafer washed with methanol, left at room temperature for 60 minutes, and then peeled again to measure the number of particles on the surface of the silicon wafer (HIA).
C-ROYCO, PC-320 / LAS346).

The above results are shown in Table 1. The table shows T
The HF insoluble content and the swelling degree are also shown.

[Table 1]

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[Procedure amendment]

[Submission date] July 5, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

The amount of the functional monomer used is appropriately determined depending on the functional group and the type of the crosslinking agent used in combination. In general, 1 0 wt% or less of the total copolymer components, especially 0. 01
~ 5 wt% is used. The amount becomes excessive incorporation percentage as a copolymerization component of 1 0% by weight, the acrylic polymer, there is a case where an acrylic polymer cross-linking excessive is formed becomes poor in adhesion when crosslinked with a crosslinking agent .

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction content]

The addition amount of the cross-linking agent is 90% insoluble in THF.
% Or more, the degree of swelling with THF is 10 times or more, and is appropriately determined depending on the acrylic polymer to be crosslinked for the purpose of forming an adhesive layer. In general, the solids content per 100 parts by weight of A acrylic-based polymer containing the emulsion, 0.001
.About.5 parts by weight, especially 0.01 to 0.5 parts by weight.

Claims (4)

[Claims] 1. A small amount of a water-soluble organic compound containing at least an acrylic acid alkyl ester having an alkyl group having 4 to 12 carbon atoms, a nonionic surfactant having a copolymerizable unsaturated group, and a functional monomer. When the THF-insoluble content is 90% or more in the emulsion containing an acrylic polymer formed by slowly emulsion-copolymerizing with a radical polymerization initiator,
A removable pressure-sensitive adhesive comprising a cross-linking agent so that the degree of swelling with HF is 10 times or more. 2. A small amount of a water-soluble organic compound containing at least an acrylic acid alkyl ester having an alkyl group having 4 to 12 carbon atoms, a nonionic surfactant having a copolymerizable unsaturated group, and a crosslinkable monomer. The THF-insoluble matter formed by gently emulsion-copolymerizing with a radical polymerization initiator is 9
A re-peelable pressure-sensitive adhesive comprising an emulsion containing a crosslinked acrylic polymer having a degree of swelling with THF of 0% or more and 10 times or more. 3. A nonionic surfactant having a copolymerizable unsaturated group is represented by the general formula: (However, R is hydrogen or an alkyl group, and n is 10 to 70.) The removable pressure-sensitive adhesive according to claim 1 or 2. 4. A THF-insoluble matter containing 90% or more of T insoluble matter, which comprises the removable pressure-sensitive adhesive according to claim 1 or 2 on a supporting substrate.
An adhesive member having an adhesive layer having a swelling degree by HF of 10 times or more.