JP2003160765A - Re-peelable self-adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a re-peelable self-adhesive sheet, sufficiently keeping self-adhesive properties to a body to be bonded when bonded to the same body at ordinary temperature and elevated temperature, and also generating no staining such as an adhesive transfer when re-peeled from the bonded body. <P>SOLUTION: A self-adhesive composition is composed of (a) a thermal- expandable fine sphere, (b) an acrylic self-adhesive, having a weight average molecular weight of 100,000 to 300,000, and having an acid value of 30 or above, that can react with a crosslinking agent (c) a tackifier resin having a softening point of 90°C or above and a solubility parameter value (a SP value) of 8.9 or above and (d) a crosslinking agent. The re-peelable self-adhesive sheet has a self-adhesive layer formed by coating a side of a base material with the self-adhesive composition. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a removable pressure-sensitive adhesive sheet which can be easily peeled from an adherend by being heated to a temperature at which the heat-expandable microspheres contained in the pressure-sensitive adhesive layer expand.
In particular, it has a high adhesive strength at a temperature 25 ° C lower than the gas vaporization temperature, and when it is peeled from the adherend after being adhered to the adherend and then heated, the adhesive residue or the like remains on the adherend. The present invention relates to a removable pressure-sensitive adhesive sheet that does not cause contamination and a processing method using the same.

[0002]

2. Description of the Related Art Conventionally, a re-peelable pressure-sensitive adhesive sheet has been used which can be attached to an adherend and easily peeled off when it is no longer needed. As such a re-releasing sheet, one having a pressure-sensitive adhesive layer containing a UV-curable oligomer on a substrate, or a pressure-sensitive adhesive having crystallinity in the side chain of an acrylic pressure-sensitive adhesive is coated on a substrate. In addition to the above, an adhesive sheet in which an adhesive layer containing heat-expandable microspheres is provided on a substrate has been proposed and used. Such a releasable pressure-sensitive adhesive sheet is used for a label or electronic part manufacturing process, for example, a flexible printed circuit board manufacturing process, a T-BGA substrate manufacturing process, a semiconductor wafer cutting process, and a monolithic ceramic capacitor into small pieces because of its easy releasability. It is used in processing steps. In particular, in the miniaturization of ceramic green sheets such as monolithic ceramic capacitors and monolithic chip inductors, in recent years, the miniaturization and its accuracy have increased, and in addition, the cutting efficiency of miniaturization has been improved.
After fixing the ceramic green sheet to the adhesive film, a temperature above the softening point temperature of the organic binder, for example,
A processing step of heating to 50 ° C. to 90 ° C. and cutting has been considered. However, the ultraviolet-curable re-peelable pressure-sensitive adhesive sheet that has been conventionally used is excellent in the adhesiveness with the green sheet when heated, but the re-peelable property after being made into small pieces is poor,
Chips that are cut into small pieces are difficult to peel off, and in the case of a re-peelable pressure-sensitive adhesive sheet having an acrylic pressure-sensitive adhesive layer with crystallinity in the side chain, its temperature range is low and the adhesive strength is weak, so it is small. It is difficult to make chips into smaller chips. Furthermore, a releasable pressure-sensitive adhesive sheet containing heat-expandable microspheres in the pressure-sensitive adhesive layer also contains microsphere particles, so that it is difficult to increase the adhesive strength, and the green sheet fragmentation processing temperature is 50 ° C to 90 ° C. Since the temperature increased to 0 ° C., the initial adhesive force thereof also tended to be greatly reduced, the accuracy of fragmentation was remarkably reduced, and the yield such as chip flying was reduced.
Since the thickness of the green sheets increases as the number of laminated green sheets increases, the processing temperature for fragmentation tends to become higher, and a processing temperature of about 120 ° C. is desired. Therefore, as a releasable pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer containing heat-expandable microspheres, a heat-peelable pressure-sensitive adhesive sheet having the center line average roughness of the surface of the pressure-sensitive adhesive layer of 0.4 μm or less and the pressure-sensitive adhesive layer. A heat-peelable pressure-sensitive adhesive sheet having a rubber-like organic elastic layer between the base material and the base material (JP 2001-131A).
No. 507) has been proposed, but it was not satisfactory in terms of adhesiveness to an adherend and processing accuracy.

[0003]

DISCLOSURE OF THE INVENTION The present invention, when applied to an adherend, can secure sufficient tackiness with the adherend not only at room temperature but also in an environment of 50 ° C. to 90 ° C. It is an object of the present invention to provide a re-peelable pressure-sensitive adhesive sheet that does not destroy the adherend when peeling it from the body and does not cause contamination such as adhesive residue on the adherend and a processing method using the same.

[0004]

As a result of intensive studies to solve the above problems, the present inventors have found that an adhesive layer provided on one surface of a substrate has an acrylic adhesive having a specific molecular weight and acid value. A pressure-sensitive adhesive sheet made of a pressure-sensitive adhesive, a pressure-sensitive adhesive composition having a cross-linking agent capable of reacting with a pressure-sensitive adhesive, a tackifying resin and heat-expandable microspheres can be used not only at room temperature but also as an adherend at a fragmentation processing temperature. It has been found that a removable pressure-sensitive adhesive sheet having excellent adhesiveness and good releasability is obtained, and the present invention has been completed based on this finding. That is, according to the present invention, the following removable pressure-sensitive adhesive sheets and processing methods are provided. (1) (a) heat-expandable microspheres on one surface of the substrate, (b) having a weight average molecular weight of 100,000 to 300,000 and capable of reacting with a crosslinking agent 30.
A pressure-sensitive adhesive composition comprising an acrylic pressure-sensitive adhesive having the above acid value, (c) a tackifying resin having a softening point of 90 ° C. or higher and a solubility parameter value (SP value) of 8.9 or higher, and (d) a cross-linking agent. A removable pressure-sensitive adhesive sheet, comprising a pressure-sensitive adhesive layer formed by applying. (2) The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the component (b) is in the range of 3 to 7, which is described in (1) above. Removable adhesive sheet. (3) The glass transition temperature of the component (b) is −30 to 0 ° C.
The removable pressure-sensitive adhesive sheet according to (1) or (2) above, wherein (4) The removable pressure-sensitive adhesive sheet according to any one of (1) to (3), wherein the softening point of the component (c) is in the range of 90 ° C to 150 ° C. (5) The removable pressure-sensitive adhesive sheet according to any one of (1) to (4), wherein the component (c) is a terpene resin. (6) The removable pressure-sensitive adhesive sheet according to any one of (1) to (5), wherein the component (d) is an epoxy-based cross-linking agent. (7) For 100 parts by mass of the component (b), 15 to 100 parts by mass of the component (a) and 0.25 to 2.
The removable pressure-sensitive adhesive sheet according to any one of (1) to (6) above, which is blended in a proportion of 0 part by mass. (8) The mixing ratio of the component (c) is 100 parts of the component (b).
The releasable pressure-sensitive adhesive sheet according to any one of (1) to (7) above, which is 10 to 100 parts by mass with respect to parts by mass. (9) In a processing method in which a pressure-sensitive adhesive sheet is adhered to at least one surface of a base material, the base material is processed, and then the pressure-sensitive adhesive sheet is peeled from the processed base material, A processing method characterized by using the removable pressure-sensitive adhesive sheet according to any one of (1) to (8). (10) The processing method according to (9), wherein the processing is a cutting process. (11) The processing method according to any one of (9) to (10), wherein the gas vaporization temperature of the component (a) is 25 ° C. or more higher than the processing temperature.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The base material used in the removable pressure-sensitive adhesive sheet of the present invention is not particularly limited and may be appropriately selected according to the field of use of the pressure-sensitive adhesive sheet, and examples thereof include polyethylene terephthalate, polyethylene naphthalate and polyethylene. Synthetic resin films such as polycarbonate, triacetyl cellulose, cellophane, polyimide, polyamide, polyphenylene sulfide, polyetherimide, polyether sulfone, aromatic polyamide, and polysulfone can be used. This base material may be transparent, may be colored by mixing various pigments or dyes into the base material, and may have a matte surface.

When the pressure-sensitive adhesive sheet is used in a field where it is exposed to an environment of about 50 to 90 ° C. for a long time, in order to avoid problems such as dimensional change and curling of the pressure-sensitive adhesive sheet, a heat shrinkage ratio is used as a base material for the pressure-sensitive adhesive sheet. Is 0.5% or less, preferably 0.2% or less. Here, the heat shrinkage rate is defined by JIS C 2318. Usually, it is preferable to select a polyethylene terephthalate film or a polyethylene naphthalate film having a heat shrinkage ratio of 0.2% or less. The thickness of the substrate may be appropriately selected depending on the field of use of the pressure-sensitive adhesive sheet, but is usually in the range of 25 μm to 250 μm. When used for holding an adherend during cutting and slicing, the thickness is in the range of 25 to 250 μm, and particularly when used in the step of slicing a ceramic sheet, 100 to 188 μm.
It is recommended that the thickness be within the range.

These pressure-sensitive adhesive sheet base materials may contain known additives, heat resistance stabilizers, oxidation resistance stabilizers, weather resistance stabilizers, UV absorbers, antistatic agents, and the like. Also,
In order to improve the adhesion between the base material and the pressure-sensitive adhesive layer, an intermediate layer having surface treatment and / or adhesiveness may be provided. As the surface treatment, for example, (1) discharge treatment such as corona discharge treatment or glow discharge treatment, (2) plasma treatment, (3)
Flame treatment, (4) ozone treatment, (5) ionizing actinic ray treatment such as ultraviolet ray treatment, electron beam and radiation treatment, (6) roughening treatment such as sand mat treatment and hairline treatment, (7) chemical treatment, etc. Is mentioned. Further, as the intermediate layer, for example, one having higher adhesiveness from the pressure-sensitive adhesive layer described later to a substrate such as a pressure-sensitive adhesive layer containing no heat-expandable microspheres than the expandable microsphere-containing pressure-sensitive adhesive layer can be used. . The thickness of the intermediate layer is preferably 1 to 100 μm, and particularly preferably 10 to 50 μm in terms of adhesion to a substrate and productivity.

The sheet of the present invention is provided on the above-mentioned base material or on the surface-treated surface and / or intermediate layer which is optionally provided,
It has a structure in which an adhesive layer is laminated. Examples of the (a) heat-expandable microspheres used for the pressure-sensitive adhesive layer include isobutane,
It is sufficient that the material is a microsphere in which a substance that is easily gasified and expanded by heating, such as propane or pentane, is enclosed in an elastic shell. The shell is often formed of a heat-meltable substance or a substance that is destroyed by thermal expansion. Examples of the substance that forms the shell include vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone. There are commercially available heat-expandable microspheres such as Microsphere [trade name, manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.]. In selecting the heat-expandable microspheres, the one having an optimum gas vaporization temperature may be appropriately selected depending on the temperature to be used, and there is no particular limitation, but the gas vaporization temperature is preferably a processing temperature such as cutting or fragmentation. It is preferable to use one having a temperature of 25 ° C. or higher. In order to efficiently reduce the adhesive strength of the adhesive layer by heat treatment, heat-expandable microspheres having a suitable strength that does not burst until the volume expansion coefficient becomes 5 times or more, preferably 7 times or more, particularly preferably 10 times or more. Is preferred. The size of the heat-expandable microspheres may be appropriately selected from the range of 10 to 17 μm in average particle diameter.

Next, in the acrylic pressure-sensitive adhesive as the component (b) constituting the pressure-sensitive adhesive layer, its weight average molecular weight is in the range of 100,000 to 300,000, and its acid value is 30 or more. If the weight average molecular weight is smaller than this range, the adhesiveness to the adherend tends to decrease, and if it exceeds 300,000, adhesive residue tends to occur. The preferable range is 120,000 to 250,000 in view of the peelability after expansion of the heat-expandable microspheres and the adhesive strength at around room temperature. The component (b) used in the present invention preferably has a ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) in the range of 3 to 7. If Mw / Mn is less than 3, the adhesive strength to the adherend tends to be low at around room temperature, and if Mw / Mn exceeds 7, sufficient adhesive strength to the adherend at high temperature cannot be obtained. It is not preferable because there is a tendency to cause residue or adhesive residue. The preferable Mw / Mn is in the range of 4 to 6 from the viewpoint of the adhesiveness to the adherend at around room temperature and high temperature. The acid value of this component (b) is 30 or more. If the acid value is less than 30, a sufficient crosslink density between the pressure-sensitive adhesive and the crosslinking agent cannot be obtained, and sufficient adhesion to the adherend at high temperature cannot be obtained, resulting in peeling after expansion of the heat-expandable microspheres. Sex decreases. Particularly, the acid value is preferably in the range of 40 to 50 from the viewpoint of the adhesiveness to the adherend at high temperature and the releasability after expansion of the heat-expandable microspheres. The acid value as referred to in this specification is the number of mg of potassium hydroxide required to neutralize the free fatty acid and resin acid contained in 1 g of the sample,
It is measured according to SK 5407 and calculated by the following formula.

[Equation 1]

The acrylic pressure-sensitive adhesive is capable of reacting with the crosslinking agent. Such include a copolymer of one or more monomer components of alkyl acrylate or methacrylic acid alkyl ester and a monomer component having a functional group capable of reacting with a crosslinking agent. Examples of the alkyl ester of acrylic acid alkyl ester or methacrylic acid alkyl ester include methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, isobutyl ester, s-butyl ester, t-butyl ester, pentyl ester, hexyl ester. , Heptyl ester, octyl ester, isooctyl ester, 2-ethylhexyl ester, isodecyl ester, dodecyl ester, tridecyl ester, pentadecyl ester, octadecyl ester, nonadecyl ester, eicosyl ester and the like. The monomer having a functional group capable of reacting with a cross-linking agent, acrylic acid whose functional group is a carboxyl group, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, In addition, etc., the functional group is a hydroxyl group hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate,
Hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, hydroxyhexyl acrylate, hydroxyhexyl methacrylate, hydroxyoctyl acrylate, hydroxyoctyl methacrylate, hydroxydecyl acrylate, hydroxydecyl methacrylate, hydroxylauryl acrylate, Examples thereof include hydroxylauryl methacrylate.
You may use these monomers individually or in combination of 2 or more types. The ratio of the (meth) acrylic acid alkyl ester to the monomer having a functional group capable of reacting with the cross-linking agent is preferably in the range of 92: 8 to 98: 2 in terms of mass ratio. When the compounding ratio of the monomer having a reactive functional group is small, the peelability from the adherend is impaired when the heat-expandable microspheres are expanded, and if it exceeds this range, Adhesion becomes poor. A particularly preferable compounding ratio is 95: 5 to 9 from the viewpoint of adhesiveness and peeling property from an adherend.
3: 7.

Furthermore, if desired, a monomer other than the above monomers may be used in combination. Examples of such substances include styrene, vinyl acetate, acrylonitrile, acrylamide, polyethylene glycol acrylate, N-vinylpyrrolidone, and tetrafurfuryl acrylate.

The component (b) can be obtained by radically copolymerizing the above monomer. The copolymerization method in this case is well known, and examples thereof include an emulsion polymerization method, a solution polymerization method, a bulk polymerization method, a suspension polymerization method, and a photopolymerization method. The glass transition temperature of the component (b) is -30 ° C to 0.
It is preferably in the range of ° C. Glass transition temperature is 0 ℃
If it exceeds, the adhesive force with the adherend is reduced, and if it is less than -30 ° C, adhesive residue is likely to occur at the time of peeling after the heat treatment, and good peelability cannot be obtained. The glass transition temperature is preferably −15 ° C. to 0 ° C. from the viewpoint of adhesiveness with an adherend and peelability after heat treatment.

In the pressure-sensitive adhesive layer of the present invention, the above (b)
The component pressure-sensitive adhesive is crosslinked with the (d) crosslinking agent. Here, the cross-linking agent may be appropriately selected according to the pressure-sensitive adhesive to be used, and is not particularly limited, and an isocyanate-based cross-linking agent, a metal chelate cross-linking agent, an epoxy-based cross-linking agent, or the like is used, but particularly the heat-expandable microspheres. After heating to a temperature at which the epoxy resin expands, it is preferable to use an epoxy-based cross-linking agent from the viewpoints of peelability from an adherend and prevention of adhesive residue. Examples of the epoxy-based crosslinking agent include bisphenol-based epoxy resins (for example, bisphenol A type, bisphenol F type, bisphenol AD type), phenol novolac type epoxy resins, ethylene glycol diglycidyl ether, 1,6
-Hexanediol glycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl aniline, diglycidyl amine, N, N, N ', N'-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N'- Diglycidylaminomethyl) cyclohexane and the like, particularly polyfunctional ones in terms of adhesiveness to an adherend at room temperature and peelability after expansion of heat-expandable microspheres, preferably tetrafunctional epoxy cross-linking Agents are preferred. Examples of such compounds include N, N, N ', N'-tetraglycidyl-m-xylenediamine and 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane. This epoxy-based cross-linking agent tends to slow the rate of cross-linking reaction, and when the reaction is insufficient, the cohesive force of the pressure-sensitive adhesive layer becomes low, and adhesive residue or the like may occur on the surface of the adherend. In order to accelerate the crosslinking reaction, (1) a catalyst such as an amine is added, (2) a monomer having an amine functional group is used as a constituent of the pressure-sensitive adhesive, and (3) an aziridine crosslinking agent is used as the crosslinking agent. It is desirable to use them together. Particularly preferred are those containing a tertiary amine having a catalytic effect in a cross-linking agent such as N, N, N ′, N′-tetraglycidyl-m-xylenediamine.

The component (d) used in the invention may be used alone or in combination of two or more kinds. The mixing ratio of the component (a) and the component (b) in the adhesive layer is
The component (a) is added in an amount of 15 to 1 to 100 parts by weight of the component (b).
It is in the range of 00 parts by mass. If the amount of component (a) is less than this range, the heat-expandable microspheres will expand and then the releasability from the adherend will decrease. If it exceeds this range, adhesion with the adherend near room temperature will occur. The power decreases. From the viewpoint of adhesiveness and peelability with respect to the adherend, the compounding ratio of the component (a) is preferably 15
~ 40 parts by mass. Further, the molar ratio of the component (b) and the component (d) is in the range of 100: 1.0 to 2.5. If the proportion of the component (d) is less than this range, adhesive residue or the like may occur on the adherend, or the releasability from the adherend may be impaired. The adhesive strength is reduced. The molar ratio of the component (b) to the component (d) is preferably 100: 1.5 to 2.0 in terms of prevention of contamination of the adherend, adhesion to the adherend, and releasability.

When an acrylic pressure-sensitive adhesive having an acid value of 30 or more is used as the component (b), the crosslinking agent is blended so that the residual amount of the functional group of the component (b) is 90% to 98%. This makes it possible to obtain a pressure-sensitive adhesive layer having a good balance between the initial peeling force and the peelability after expansion of the heat-expandable microspheres. When the residual amount of the functional group of the component (b) is less than 90%, the initial peeling force is improved, but the peelability after the expansion of the heat-expandable microspheres, particularly the occurrence of adhesive residue, is observed and exceeds 98%. And the peelability after expansion of the heat-expandable microspheres is improved, but the initial peel force is reduced. The preferred residual amount of functional group of component (b) is 9
It is in the range of 2% to 96%.

The adhesive layer has a softening point of 90 ° C. (c) in order to control the adhesion with the adherend at room temperature.
As described above, it is necessary to use a tackifying resin having an SP value of 8.9 or more. As the component (c), for example, α-pinene-based, β-pinene-based, dipentene-based, terpene-phenol-based terpene-based resins and gum-based, wood-based, tall oil-based natural rosins, or hydrogenated to these , Disproportionation, polymerization,
Examples thereof include rosin-based resins such as rosin-based derivatives that have undergone maleation and esterification, petroleum resins, coumarone-indene resins, and the like.
It is preferably in the range of 150 ° C. Above all, the terpene phenol-based tackifying resin has little contamination to the adherend and little adhesive residue, and is excellent in the adhesiveness to the adherend in an environment of 50 ° C to 90 ° C, and is a heat-expandable microsphere. After expansion, an adhesive layer that can be easily peeled from the adherend can be obtained, which is preferable. The mixing ratio of the component (c) is in the range of 10 to 100 parts by mass with respect to 100 parts by mass of the component (b). If the amount of the component (c) is less than this range, the adhesive strength to the adherend is lowered in the range of room temperature to 100 ° C, and if it exceeds this range, the sticking property to the adherend at room temperature is deteriorated. . From the standpoints of adhesiveness to an adherend and sticking property at room temperature, the compounding ratio of the component (c) is preferably 20 to 60 parts by mass. Furthermore, the solubility parameter value (SP) is 8.
It is necessary to use the component (d) having a ratio of 9 or more, preferably 8.98 or more. This makes it possible to prevent adhesive residue on the adherend and the occurrence of contamination, and to form a pressure-sensitive adhesive layer having excellent releasability. Obtainable. Here, the solubility parameter value (S
The P value) is obtained from the following Holly calculation formula.

Δ = d · ΣG / M (2) [δ: solubility parameter (SP value), d: density (g / m)
l), G: Molecular attraction constant of each functional group (cal / ml)
^1/2 / mol, M: molecular weight (g / mol)] When the solubility parameter (SP value) is smaller than 8.9, the compatibility with the component (b) is poor and a uniform pressure-sensitive adhesive layer is obtained. However, even when a uniform pressure-sensitive adhesive layer is obtained, the adhesiveness to the adherend is significantly reduced, and adhesive residue is likely to occur after heat peeling. Furthermore, this (c)
The component preferably has a hydroxyl value of 30 or more. If the hydroxyl value is less than 30, adhesive residue is likely to occur on the adherend during peeling, which is not preferable.

In the removable pressure-sensitive adhesive sheet of the present invention, in order to form a pressure-sensitive adhesive layer on a substrate, the above-mentioned components are dissolved or dispersed in a suitable solvent so that the solid content concentration is about 20 to 50% by mass. A pressure-sensitive adhesive is prepared by preparing a pressure-sensitive adhesive layer-forming coating liquid and applying and drying the pressure-sensitive adhesive layer-forming coating liquid on a substrate or a surface-treated surface or an intermediate layer provided as desired according to a conventional method. The layer is provided in the range of 20 to 100 μm.
If the layer thickness is thicker than this range, cohesive failure is likely to occur at the time of peeling after heat treatment, and good peelability cannot be obtained. If it is thinner than this range, sufficient adhesive force with the adherend is obtained. Will not be obtained. In addition, the amount of volatile matter remaining in the pressure-sensitive adhesive layer (hereinafter referred to as the amount of residual volatile matter) causes the adhesiveness between the pressure-sensitive adhesive layer and the substrate and the adhesion after heating above the temperature at which the heat-expandable microspheres expand. It may adversely affect peelability from the body and adhesive residue. Therefore, the residual volatile content in the pressure-sensitive adhesive layer is preferably 4% by mass or less, and particularly preferably 2% by mass or less. At this time, various conventionally used additives such as surfactants, lubricants, stabilizers, and viscosity modifiers can be added to the pressure-sensitive adhesive layer-forming coating liquid.

[0018]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The physical properties of the removable pressure-sensitive adhesive sheet were evaluated according to the methods described below.

(1) Initial peeling force (N / 25 mm) As an adherend, SUS304 was treated according to JIS K-0237 and used, a pressure sensitive adhesive sheet having a width of 10 mm was pasted to obtain a 180 ° peeling force, and converted to a width of 25 mm. did. (2) Heat Peeling Force The sample prepared in (1) above was placed on a hot plate at 80 ° C., and a 180 ° peeling force was determined according to JIS K-0237. (3) Peelability After sticking to SUS304, it was heated at 130 ° C. for 1 minute on a hot plate, allowed to cool, and whether or not the pressure-sensitive adhesive sheet foamed and peeled at room temperature was evaluated according to the following criteria. ⊚: After cooling, the pressure-sensitive adhesive sheet is peeled off from the adherend without applying any force. ◯: Peel from the adherend after touching the adhesive sheet with a finger. Δ: A force is applied to the pressure-sensitive adhesive sheet to peel it off without leaving an adhesive residue. X: Not peeled from the adherend, and when peeled, adhesive residue is seen. (4) Contamination to adherend The surface of SUS304 peeled off in the above test (3) was evaluated according to the following criteria. ◯: No color change or adhesive residue is observed on the adherend. X: Discoloration or adhesive residue is observed on the adherend.

Example 1 Thermally expandable microspheres (Product name: Microsphere F-50
D, Matsumoto Yushi-Seiyaku Co., Ltd., average particle diameter 15 μm, gas vaporization temperature 115 ° C. by TMA method) 8.8 parts by mass, 2-ethylhexyl acrylate, methacrylic acid, methyl methacrylate are copolymerized by a conventional method. Acrylic adhesive (Mw
= 180,000, Mn = 30,000, glass transition temperature-10 ° C, oxidation 45) 35 parts by mass, terpene phenol-based tackifying resin (softening point 125 ° C, SP value 9.32, hydroxyl value 200).
14 parts by mass, 0.2 parts by mass of an epoxy-based cross-linking agent (N, N, N'N'-tetraglycidyl-m-xylenediamine) and 42 parts by mass of toluene are uniformly mixed and dissolved to give an adhesive layer forming coating solution. Prepared. This coating solution was applied onto a polyethylene terephthalate sheet having a thickness of 100 μm by a baker type applicator and dried sufficiently at 80 ° C. to give a thickness of 5
A pressure-sensitive adhesive layer having a thickness of 0 μm was formed to prepare a removable pressure-sensitive adhesive sheet. Table 1 shows the physical properties of this pressure-sensitive adhesive sheet.

Example 2 The epoxy resin (N, N'-di (glycidyl) -o-toluidine) manufactured by Nippon Kayaku Co., Ltd. was used as the crosslinking agent in Example 1.
An adhesive sheet was produced in the same manner as in Example 1 except that 0.4 part by mass was used. Table 1 shows the physical properties of this pressure-sensitive adhesive sheet.

Example 3 In Example 1, the tackifying resin was a terpene phenol resin (softening point 145 ° C., SP value 8.98, hydroxyl value 6).
0) was 3.5 parts by mass and toluene was 52.5 parts by mass, and an adhesive sheet was produced in the same manner as in Example 1. Table 1 shows the physical properties of this pressure-sensitive adhesive sheet.

Example 4 The same as Example 1 except that the crosslinking agent was 0.1 part by mass of an epoxy resin (1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane). Then, an adhesive sheet was produced. Table 1 shows the physical properties of this pressure-sensitive adhesive sheet.

Comparative Example 1 In Example 1, the acrylic pressure-sensitive adhesive was manufactured by Soken Chemical Industry Co., Ltd.
SK Dyne 1501B (Mw = 1.3 million, Mn = 15
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the acid value was 8 and the glass transition temperature was -41 ° C. Table 1 shows the physical properties of this pressure-sensitive adhesive sheet.

Comparative Example 2 An adhesive sheet was prepared in the same manner as in Example 1 except that the tackifying resin used in Example 1 was liquid at room temperature (product name: YP-90LL, manufactured by Yasuhara Chemical Co., Ltd.). . Table 1 shows the physical properties of this pressure-sensitive adhesive sheet.

Comparative Example 3 In Example 3, the tackifying resin was a terpene phenol resin having a softening point of 80 ° C. (product name: YS Polystar T-8).
0, manufactured by Yasuhara Chemical Co., SP value 8.98, hydroxyl value 60), except that the adhesive sheet was produced in the same manner as in Example 3. Table 1 shows the physical properties of this pressure-sensitive adhesive sheet.

Comparative Example 4 Except that in Example 3, the tackifying resin was phenol-modified rosin (product name: Neotol 125P, manufactured by Harima Kasei Co., softening point 125 ° C., SP value 7.76, hydroxyl value 26). An adhesive sheet was produced in the same manner as in Example 3. Table 1 shows the physical properties of this pressure-sensitive adhesive sheet. In the pressure-sensitive adhesive sheet of the present invention, the compatibility of the pressure-sensitive adhesive layer was poor and a uniform pressure-sensitive adhesive sheet could not be obtained.

[0028]

[Table 1]

[0029]

EFFECTS OF THE INVENTION The removable pressure-sensitive adhesive sheet of the present invention has excellent adhesiveness to an adherend, and when peeled off,
The adherend is free from contamination such as adhesive residue. Also,
In the cutting and perforating processing of the ceramic green sheet using the pressure-sensitive adhesive sheet of the present invention, even if the processing temperature is higher than the softening point temperature of the organic binder, the peeling force from the adherend affects the processing accuracy. It can be maintained in a range that does not exist, and can be easily peeled off without contaminating the adherend after the expansion of the heat-expandable microspheres.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ identification code FI theme code (reference) // B05D 7/24 301 B05D 7/24 301K (72) Inventor Satoshi Asai 4-11 Ginza, Chuo-ku, Tokyo No. 2 Somer Co., Ltd. F-term (reference) 4D075 BB08Z BB22Z BB23Z CA07 DA06 DB31 DB33 DB34 DB36 DB44 DB48 DB53 DB55 DC19 DC21 EA07 EA31 EA35 EB12 EB22 EB33 EB52 EB53 EB54 EB56 EC41 4J004 CAA06 AB02 A01 CD07 CD08 CD09 CD10 CE01 FA08 4J040 DC072 DD022 DF011 DF041 DF051 DF082 DG001 DN072 EC032 EC042 EC062 EC072 EC162 EJ032 JA09 JB09 KA16 KA26 LA01 LA02 PA23 PA42

Claims (11)

[Claims] 1. A (a) heat-expandable microsphere on one surface of a substrate,
(B) An acrylic pressure-sensitive adhesive having a weight average molecular weight of 100,000 to 300,000 and an acid value of 30 or more capable of reacting with a cross-linking agent, and (c) a softening point of 90 ° C. or more, and a solubility parameter value (SP
A removable pressure-sensitive adhesive sheet, comprising a tackifier resin having a value of 8.9 or more and a pressure-sensitive adhesive layer formed by applying a pressure-sensitive adhesive composition comprising (d) a crosslinking agent. 2. A weight average molecular weight (Mw) of the component (b).
And the number average molecular weight (Mn) ratio (Mw / Mn) is 3 to
7. The removable pressure-sensitive adhesive sheet according to claim 1, which is in the range of 7. 3. The glass transition temperature of the component (b) is -3.
The temperature is in the range of 0 to 0 ° C.
The removable pressure-sensitive adhesive sheet according to. 4. The softening point of the component (c) is 90 ° C. to 15 ° C.
The removable pressure-sensitive adhesive sheet according to any one of claims 1 to 3, which has a temperature range of 0 ° C. 5. The removable pressure-sensitive adhesive sheet according to claim 1, wherein the component (c) is a terpene resin. 6. The removable pressure-sensitive adhesive sheet according to claim 1, wherein the component (d) is an epoxy-based crosslinking agent. 7. The component (a) is contained in an amount of 15 to 100 parts by weight, and the component (d) is added in an amount of 0.1 to 100 parts by weight of the component (b).
The removable pressure-sensitive adhesive sheet according to any one of claims 1 to 6, wherein the removable pressure-sensitive adhesive sheet is blended in a proportion of 25 to 2.0 parts by mass. 8. The re-peeling method according to claim 1, wherein the blending ratio of the component (c) is 10 to 100 parts by mass with respect to 100 parts by mass of the component (b). Adhesive sheet. 9. A processing method in which an adhesive sheet is adhered to at least one surface of a substrate, the substrate is processed, and then the adhesive sheet is peeled from the processed substrate,
A releasable pressure-sensitive adhesive sheet according to any one of claims 1 to 8 is used as the pressure-sensitive adhesive sheet. 10. The processing method according to claim 9, wherein the processing is cutting processing. 11. The processing method according to claim 9, wherein the gas vaporization temperature of the component (a) is 25 ° C. or more higher than the processing temperature.