JP2005330407A - Repeelable adhesive sheet and method for processing adherend by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prepare a repeelable adhesive sheet capable of readily peeling it from an adherend without generating contamination such as paste residue on the adherend by heating and being usable by an adhesive layer alone. <P>SOLUTION: The repeelable adhesive sheet has a film-shaped or sheet-shaped substrate and an adhesive layer provided on at least either one surface of the substrate and composed of an adhesive composition containing thermally expandable fine small spheres and an adhesive. In the adhesive sheet, the surface of the substrate on which the adhesive layer is provided is a surface having peelable properties and the substrate is peelable under non-heating conditions from the adhesive layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a releasable pressure-sensitive adhesive sheet and a method for processing an adherend using the releasable pressure-sensitive adhesive sheet. More specifically, the present invention easily peels without causing contamination such as adhesive residue on the adherend by heating. In addition, the present invention relates to a releasable pressure-sensitive adhesive sheet that can be used alone, and a method for processing an adherend using the removable pressure-sensitive adhesive sheet.

  Conventionally, an adhesive member in which an adhesive layer containing thermally expandable microspheres is disposed on one side of a substrate has been proposed and used (see, for example, Patent Documents 1 to 4). Such an adhesive member is widely used in the electric / electronic industry as a releasable adhesive sheet that can be easily peeled off after it has been attached to an adherend and is no longer needed after it has been used. Specifically, it is suitably used as a backing sheet or a semiconductor wafer cutting step in a flexible printed circuit board (FPC) manufacturing process, a temporary fixing sheet in a small-size processing step of a multilayer ceramic capacitor, a plating masking sheet, or the like.

  In recent years, the development speed of thinned and highly accurate products in the electrical and electronic industries has been remarkable, but from a global perspective, needs for environmental protection measures and reduction of energy consumption are also increasing. . In order to meet such needs, the re-peelable pressure-sensitive adhesive sheet needs to contribute to the enhancement of functions such as high adhesion and high reliability, as well as environmental and resource protection, cost reduction, and production time reduction. is there.

  For example, in the FPC manufacturing process, there is a growing demand for the development of a backing sheet that can simultaneously process both sides of an adherend for the purpose of reducing the cost and production time as well as making the substrate thinner and more accurate. As a related prior art, a heat-foaming type pressure-sensitive adhesive member in which pressure-sensitive adhesive layers are provided on both surfaces of a base material has been proposed (see, for example, Patent Documents 5 and 6). However, these pressure-sensitive adhesive members are characterized by different peelability on both sides, and do not enable simultaneous processing on both sides of an adherend.

Moreover, the heat foaming type adhesive member which provided the heat foaming type adhesive layer in the single side | surface or both surfaces of the base material is proposed (for example, refer patent documents 7-9). However, when these pressure-sensitive adhesive members are used in a so-called roll-to-roll manufacturing process or the like, there is a problem that satisfactory followability is not exhibited and floating occurs in the process. Furthermore, the production of the pressure-sensitive adhesive sheet requires more steps and the productivity is not good. Further, when the work is performed at a high temperature, the adherend may be damaged due to thermal contraction of the base material.
JP-A-11-302614 JP 2000-351947 A JP 2002-69422 A JP 2003-160765 A JP 2000-248240 A Japanese Patent No. 2613389 Japanese Patent No. 1679239 JP 2002-69410 A JP 2001-57472 A

  The present invention uses a releasable pressure-sensitive adhesive sheet that can be easily peeled off without causing contamination such as adhesive residue on the adherend by heating, and a releasable pressure-sensitive adhesive sheet that can be used alone. An object of the present invention is to provide an adherend processing method excellent in processing accuracy and productivity.

  As a result of intensive studies, the inventors of the present invention solve the above problem by making the surface of the base material on which the predetermined adhesive layer is disposed a surface having peelability and making the base material peelable from the adhesive layer. It came to make this invention. That is, according to the present invention, the following releasable pressure-sensitive adhesive sheet and adherend processing method are provided.

[1] A film-like or sheet-like base material, and an adhesive layer made of an adhesive composition containing thermally expandable microspheres and an adhesive, disposed on at least one surface of the base material. A re-peelable pressure-sensitive adhesive sheet, wherein a surface of the base material on which the pressure-sensitive adhesive layer is disposed is a surface having releasability, and the base material can be peeled from the pressure-sensitive adhesive layer under non-heating conditions. Peelable adhesive sheet.

[2] The releasable pressure-sensitive adhesive sheet according to [1], wherein the pressure-sensitive adhesive composition has an elastic modulus at 25 ° C. of 1.0 × 10 ^{5 to} 7.0 × 10 ⁸ Pa.

[3] The releasable pressure-sensitive adhesive sheet according to [1] or [2], wherein the pressure-sensitive adhesive is an acrylic pressure-sensitive adhesive having in its molecular structure an active group capable of reacting with a crosslinking agent.

[4] A first adherend is adhered to the surface of the pressure-sensitive adhesive layer of the releasable pressure-sensitive adhesive sheet according to any one of [1] to [3], and the substrate is peeled off under non-heating conditions. Then, the surface of the adhesive layer is exposed, and the second adherend is adhered to the exposed surface of the adhesive layer, and at least one of the first and second adherends is predetermined. An adherend processing method comprising: processing and then obtaining the processed adherend subjected to the predetermined processing by heating and peeling the adhesive layer.

[5] The adherend processing method according to [4], wherein the predetermined processing includes processing for patterning at least a predetermined conductor layer, and is a processing for manufacturing a flexible printed circuit board (FPC).

[6] The adherend processing method according to [4], wherein the predetermined process is a cutting process.

[7] The adherend processing method according to [4], wherein the predetermined processing is a conductor layer forming processing.

  The releasable pressure-sensitive adhesive sheet of the present invention can be easily peeled off without causing contamination such as adhesive residue on the adherend by heating, and can be used alone in a so-called roll-to-roll manufacturing process. The effect that it is.

  Moreover, according to the adherend processing method of the present invention, a releasable pressure-sensitive adhesive sheet that can be easily peeled off without causing contamination such as adhesive residue on the adherend by heating and can be used alone. Therefore, it is possible to improve the accuracy of processing the adherend and improve the processing efficiency.

  Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments, and may be appropriately selected based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that design changes, improvements, etc. may be made.

  The releasable pressure-sensitive adhesive sheet of the present invention comprises a film-like or sheet-like base material, and a pressure-sensitive adhesive composition comprising thermally expandable microspheres and a pressure-sensitive adhesive disposed on at least one surface of the base material. A releasable pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer, the surface of the base material on which the pressure-sensitive adhesive layer is disposed is a surface having peelability, and the base material can be peeled off from the pressure-sensitive adhesive layer under non-heating conditions. Is. The details will be described below.

  As for the base material which comprises the releasable adhesive sheet which is embodiment of this invention, the surface (adhesion layer arrangement | positioning surface) by which an adhesion layer is arrange | positioned has peelability. By using a base material having such an adhesive layer-providing surface, the base material can be peeled off from the adhesive layer under non-heating conditions. Here, the phrase “removable under non-heating conditions” as used in the present invention means that it can be easily peeled off, for example, at room temperature (around 25 ° C.) without any heat treatment. . Examples of the substrate having such a peelable adhesive layer-providing surface include films and sheets made of various resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene, polypropylene, and polyarylate, polyethylene laminated paper, and polybutylene. Various paper materials such as laminated paper, crea-coated paper, resin-coated paper, and glassine paper can be exemplified, and among these, it can be appropriately selected according to the application field of the pressure-sensitive adhesive sheet. Moreover, the base material by which the mold release process was performed to the adhesion layer arrangement | positioning surface can also be used suitably.

  Examples of the release treatment applied to the adhesive layer-providing surface of the substrate include a release agent layer forming treatment by applying a release agent such as a silicone resin, a long chain alkyl resin, or a fluorine resin. Can do. The substrate may be transparent, or may be colored by blending various pigments and dyes with the material constituting the substrate, and the surface may be processed into a mat shape.

  The releasable pressure-sensitive adhesive sheet according to an embodiment of the present invention has a laminated structure in which a pressure-sensitive adhesive layer is disposed on the surface of the above-described base material having peelability. This adhesive layer is formed of an adhesive composition containing thermally expandable microspheres and an adhesive. The heat-expandable microspheres contained in the pressure-sensitive adhesive composition are obtained by encapsulating a substance (vaporizing substance) that easily gasifies and expands when heated to a predetermined temperature in an elastic shell. Preferable examples of the vaporized substance contained in the shell include substances such as pentane, hexane, heptane, and octane, or a mixture of these substances. In addition, a vaporization substance can be suitably selected according to the desired temperature which is going to expand a thermally expansible microsphere.

  Examples of the shell enclosing the vaporized material described above include those formed of a heat-meltable material or a material that is destroyed by thermal expansion. Examples of the substance forming the shell include vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone. Specific examples of the thermally expandable microspheres include commercially available products such as microspheres (trade name (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.)). Further, the thermally expandable microsphere has an appropriate strength that does not rupture until the volume expansion coefficient of the vaporized substance contained therein is 5 times or more, preferably 7 times or more, particularly preferably 10 times or more. It is preferable because the adhesive force of the adhesive layer can be efficiently reduced by heat treatment. Furthermore, the size of the thermally expandable microspheres is preferably selected as appropriate from the range of 10 to 90 μm in terms of average particle diameter.

  The pressure-sensitive adhesive contained in the pressure-sensitive adhesive composition may be either a rubber-based pressure-sensitive adhesive or an acrylic pressure-sensitive adhesive, but exhibits a holding force and a strong pressure-sensitive adhesive force under temperature conditions before expansion of the thermally expandable microsphere. An acrylic adhesive is preferred. The acrylic pressure-sensitive adhesive includes a copolymer of a monomer component of acrylic acid alkyl ester and / or methacrylic acid alkyl ester and a monomer having a functional group capable of reacting with a crosslinking agent. That is, the acrylic pressure-sensitive adhesive preferably has an active group capable of reacting with the crosslinking agent in its molecular structure. Examples of the active group include a carboxyl group, a hydroxyl group, and an amide group.

  Examples of the alkyl ester constituting the acrylic acid alkyl ester and 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. Examples thereof include esters, heptyl esters, octyl esters, isooctyl esters, 2-ethylhexyl esters, isodecyl esters, dodecyl esters, tridecyl esters, pentadecyl esters, octadecyl esters, nonadecyl esters, and eicosyl esters.

  As a monomer having a functional group capable of reacting with a crosslinking agent, acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, whose functional group is a carboxyl group, In addition, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, hydroxyhexyl acrylate, hydroxyhexyl methacrylate whose functional group is a hydroxyl group , Hydroxyoctyl acrylate, hydroxyoctyl methacrylate, hydroxydecyl acrylate, hydroxydecyl methacrylate, hydroxylauryl acrylate, hydroxylaur methacrylate In addition, acrylic acid amide, methacrylic acid amide whose functional group is an amide group, dimethylaminoethyl methacrylate, dimethylaminomethyl methacrylate, tertiary butylaminoethyl methacrylate, etc. whose functional group is a reactive amino group, etc. Can be mentioned. These monomers may be used alone or in combination of two or more.

  Further, if desired, monomers other than those described above may be used in combination. Specific examples include styrene, vinyl acetate, acrylonitrile, acrylamide, polyethylene glycol acrylate, N-vinyl pyrrolidone, and tetrafurfuryl acrylate.

  The pressure-sensitive adhesive can be obtained by radical copolymerization of the aforementioned acrylic acid alkyl ester and / or methacrylic acid alkyl ester monomer and a monomer having a functional group capable of reacting with the crosslinking agent. 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 pressure-sensitive adhesive may be crosslinked with a crosslinking agent. The crosslinking agent may be appropriately selected according to the pressure-sensitive adhesive, and is not particularly limited. Specifically, an isocyanate crosslinking agent, a metal chelate crosslinking agent, an epoxy crosslinking agent, and the like are used.

  Moreover, it is preferable to add various resins as a glass transition point control agent to the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer because the adhesion to the adherend can be controlled. Preferred examples of the resin to be added include rubber, tackifier resin, wax, acrylic resin, polyester resin, urethane resin, amide resin, and epoxy resin.

The elastic modulus at 25 ° C. of the pressure-sensitive adhesive composition is preferably 1.0 × 10 ^{5 to} 7.0 × 10 ⁸ Pa, and preferably 2.0 × 10 ^{5 to} 6.5 × 10 ⁸ Pa. More preferably, it is 4.0 × 10 ^{5 to} 6.0 × 10 ⁸ Pa. When the elastic modulus at 25 ° C. is less than 1.0 × 10 ⁵ Pa, the adhesive force and holding force of the pressure-sensitive adhesive tend to be extremely lowered under heating conditions, and is over 7.0 × 10 ⁸ Pa. The followability to the adherend tends to decrease. The “elastic modulus” referred to in the present invention is a thickness of 0.1 mm × width of 3 mm × length obtained by peeling a pressure-sensitive adhesive composition as a sample after coating and drying on a predetermined substrate. The value (Pa) measured under the condition of a load of −0.2 to −0.5 g by a TMA tensile mode method using a 15 mm sample sheet. Details of the elastic modulus measurement method will be described later.

  Next, a method for producing a releasable pressure-sensitive adhesive sheet according to an embodiment of the present invention will be outlined. First, in order to form an adhesive layer on the surface of a film-like or sheet-like substrate, the above-mentioned adhesive composition is dissolved or dispersed in an appropriate solvent, and the solid content concentration is about 20 to 60% by mass. An adhesive layer forming coating solution is prepared. Subsequently, after applying this adhesive layer formation coating liquid on the surface of a base material in accordance with a conventional method, the adhesive layer is formed by drying, and a releasable adhesive sheet can be produced. What is necessary is just to let the thickness of the adhesion layer to form be 15-100 micrometers. If the thickness of the adhesive layer is more than 100 μm, cohesive failure is likely to occur at the time of peeling after the heat treatment, so that good peelability may not be obtained. If the thickness is less than 15 μm, sufficient adhesion with the adherend is obtained. May not be able to obtain a sufficient adhesive strength.

  Depending on the amount of volatile component remaining in the adhesive layer (hereinafter referred to as “residual volatile component amount”), after heating to a temperature higher than the temperature at which the adhesiveness between the adhesive layer and the substrate or the thermally expandable microspheres expands May adversely affect the peelability from the adherend and the adhesive residue. Accordingly, the residual volatile content in the adhesive layer is preferably 4% by mass or less, and more preferably 2% by mass or less. In addition, what is necessary is just to adjust the quantity of the solvent for preparing the adhesion layer formation coating liquid, the drying time after coating, etc. in order to set it as the desired residual volatile matter amount. Various conventionally used additives such as surfactants, lubricants, stabilizers, viscosity modifiers, dyes, and the like can be added to the adhesive layer forming coating solution.

  If the peelable adhesive sheet of this embodiment peels and removes the base material constituting this, and constitutes a laminate (laminate A) in which the adherend to be processed is adhered to both sides of the adhesive layer, Processing of such an adherend can be facilitated. In addition, an adherend to be processed is formed on one surface of the adhesive layer, and a laminate (laminate B) in which an appropriate support or a jig used in a predetermined manufacturing process is attached to the other surface. Even so, the processing of the adherend can be facilitated.

  Next, the adherend processing method of the present invention will be described. In the adherend processing method of the present invention, the first adherend is adhered to the surface of the pressure-sensitive adhesive layer of any of the above-described releasable pressure-sensitive adhesive sheets, and the base material is peeled off under non-heating conditions. In a state where the surface of the layer is exposed and the second adherend is adhered to the surface of the exposed adhesive layer, predetermined processing is performed on at least one of the first and second adherends, and then the adhesive It is an adherend processing method including obtaining a processed adherend that has been subjected to predetermined processing by heating and peeling a layer. The details will be described below.

  In the adherend processing method according to the embodiment of the present invention, the adherends to be processed (first and second adherends) are, for example, polyethylene terephthalate, polyethylene naphthalate, polyethylene, polycarbonate, triacetyl. Films and sheets made of heat-resistant synthetic resins such as cellulose, cellophane, polyimide, polyamide, polyphenylene sulfide, polyetherimide, polyethersulfone, aromatic polyamide, polysulfone, and liquid crystal polymer, sheets made of glass, metal, or ceramic Etc. Moreover, the laminated composite which laminated | stacked several types of the materials which comprise these adherends can also be used as an adherend. The first adherend and the second adherend may be the same or different. Furthermore, one adherend of the first or second adherend is used as an appropriate support or a jig used in a predetermined manufacturing process, and predetermined processing is performed only on the other adherend. You can also.

  According to the adherend processing method of the present embodiment, any one of the releasable adhesive sheets described so far is used. If this re-peelable pressure-sensitive adhesive sheet is used, the substrate constituting it can be easily peeled and removed from the pressure-sensitive adhesive layer under non-heated conditions, so the adherend to be processed is stuck on both sides of the pressure-sensitive adhesive layer. Thus, a so-called substrate-less laminate (laminate A) can be formed. In the adherend processing method of the present embodiment, an adherend (first adherend and / or second adherend) constituting the laminate in a state where such a substrate-less laminate is constituted. Since the predetermined processing is performed on the body, it is possible to realize high followability of the laminated body, thin film of the adherend, and resource saving in the manufacturing process. In addition, since the predetermined processing is performed without the base material, it is not affected by the dimensional change of the base material even when the work is performed under a high temperature condition, for example. High processing can be performed. Therefore, according to the adherend processing method of the present embodiment, the FPC is manufactured, the semiconductor wafer is cut, the multilayer ceramic capacitor is made smaller, the conductive layer is formed on the adherend surface by plating, sputtering, and the like. be able to.

  In the adherend processing method of the present embodiment, at least one of the first and second adherends has a conductor layer formed on the surface thereof, including a copper clad laminate (CCL). The processing for manufacturing the FPC, in which the predetermined processing performed on the adherend in a state of being attached to the adhesive layer includes at least the step of patterning the conductor layer. Preferably there is. That is, in the adherend processing method of this embodiment, since any one of the releasable adhesive sheets described so far is used, highly accurate pattern wiring can be efficiently formed on the adherend.

  Next, an outline of an example of processing for manufacturing an FPC including the step of patterning the conductor layer on the adherend surface will be described. First, prior to performing the processing for manufacturing the FPC, the above-described laminate A or B is configured using the releasable pressure-sensitive adhesive sheet of the present invention. Specifically, a substrate (first adherend) to be processed is first attached to the surface of the adhesive layer of the releasable adhesive sheet. Next, the base material is peeled off under non-heating conditions to expose the surface of the adhesive layer, and a substrate (second adherend) that is also a processing target is adhered thereto. The substrate (first adherend and second adherend) to be processed is, for example, a copper-clad laminate (CCL) or the like, and the laminate A is obtained by sticking the resin surface to the adhesive layer. Can be configured. Further, if either the first adherend or the second adherend is an appropriate support that is not an object to be processed or a jig that is used in a predetermined manufacturing process, the laminate B is configured. can do. Furthermore, you may comprise the laminated body C by pinching | interposing various films, a sheet | seat, a resin board, etc. between the adhesion layer of a re-peeling adhesive sheet, and a base material.

  Thereafter, the conductor layer disposed on the surface of the adherend is patterned. The patterning may be carried out by various methods for producing a conventionally known single-sided FPC, and specific examples include the following photographic methods and printing methods. After patterning is complete, if the re-peelable adhesive sheet is peeled off by heating to a temperature higher than the expansion temperature of the heat-expandable microspheres, it will be processed without applying an excessive load to the processed adherend. An FPC which is a finished adherend can be obtained.

[Photographing method]: First, a liquid photosensitive agent is applied and dried, or a photosensitive dry film is attached to the entire surface of the conductor layer. Next, only the conductor pattern portion is exposed and developed to leave an etching resistant film at the exposed portion. Next, the exposed unnecessary portion of the conductor (portion other than the conductor pattern portion) is dissolved and removed with an etching solution. Thereafter, the etching resist layer is peeled and removed to form and expose the conductor pattern portion, and the coverlay film is bonded to the surface of the exposed conductor pattern portion, and the coverlay film is cured by heating and pressing at about 150 ° C. Thus, the conductor layer is patterned.

[Printing method]: First, an etching resistant ink is printed (applied) and dried on the surface of the conductor layer by screen printing. Next, the exposed unnecessary portion of the conductor (portion other than the conductor pattern portion) is dissolved and removed with an etching solution. Thereafter, the etching resist layer is peeled and removed to form and expose the conductor pattern portion, and the coverlay film is bonded to the surface of the exposed conductor pattern portion, and the coverlay film is cured by heating and pressing at about 150 ° C. Thus, the conductor layer is patterned.

  Moreover, in the adherend processing method of this embodiment, it is preferable that the predetermined process performed with respect to the adherend in the state stuck on the releasable adhesive sheet is a cutting process. That is, in the adherend processing method of the present embodiment, since any of the releasable adhesive sheets described so far is used, high followability of the laminate in the manufacturing process, thinning of the adherend, and resource saving. Can be realized. In addition, since processing is performed without a base material, for example, even when working under high temperature conditions, it is not affected by dimensional changes of the base material, and highly accurate processing is performed on the adherend. It can be performed. Furthermore, the pressure-sensitive adhesive layer can be peeled off without applying an excessive load to the processed adherend that has been cut, and a processed adherend that is free from defects such as damage can be easily obtained.

  Prior to performing the cutting process, the above-described laminate B is configured using the releasable pressure-sensitive adhesive sheet which is an embodiment of the present invention. The adherend to be processed is, for example, a ceramic sheet or a semiconductor wafer. In addition, you may comprise the laminated body C by pinching | interposing various films, a sheet | seat, a resin board, etc. between the adhesion layer of a re-peeling adhesive sheet, and a support body or a jig | tool. Next, the laminated body B or C adherend is subjected to a cutting process such as fragmentation. After the cutting process is completed, if the re-peelable adhesive sheet is peeled off by heating to a temperature equal to or higher than the expansion temperature of the heat-expandable microspheres, it will be processed without applying an excessive load to the processed adherend. A finished adherend can be obtained.

  Moreover, in the adherend processing method of this embodiment, it is preferable that the predetermined process performed with respect to the adherend in the state affixed on the releasable adhesive sheet is a conductor layer forming process. That is, in the adherend processing method of the present embodiment, since any of the releasable adhesive sheets described so far is used, high followability of the laminate in the manufacturing process, thinning of the adherend, and resource saving. Can be realized. In addition, since processing is performed without a base material, for example, even when working under high temperature conditions, it is not affected by dimensional changes of the base material, and highly accurate processing is performed on the adherend. It can be performed. Furthermore, the pressure-sensitive adhesive layer can be peeled without applying an excessive load to the processed adherend subjected to the conductor layer forming process, and a processed adherend free from defects such as damage can be easily obtained. it can. Specific examples of the conductor layer forming process include plating, laminating, and sputtering.

  Prior to performing the conductor layer forming process, the above-described laminate A or B is configured using the releasable pressure-sensitive adhesive sheet which is an embodiment of the present invention. The adherend to be processed is, for example, polyethylene terephthalate, polyethylene naphthalate, polyethylene, polycarbonate, triacetylcellulose, cellophane, polyimide, polyamide, polyphenylene sulfide, polyetherimide, polyethersulfone, aromatic polyamide, polysulfone, liquid crystal polymer It is a synthetic resin film or sheet having heat resistance such as. In addition, you may comprise the laminated body C by pinching | interposing various films, a sheet | seat, a resin board, etc. between the adhesion layer and base material of a re-peeling adhesive sheet. Next, a conductor layer forming process is performed on the adherend of the laminate A, B, or C according to a conventional method. After the conductor layer forming process is completed, if the re-peelable adhesive sheet is peeled off by heating to a temperature equal to or higher than the expansion temperature of the heat-expandable microsphere, an excessive load is applied to the processed adherend. A processed adherend can be obtained without application of.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.

(Example 1)
Thermally expandable microspheres (F-50D (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.)) 8.3 parts by mass, acrylic adhesive (solid content = 35% by mass, Mw = 500,000, glass transition point = −31 ° C. (Nippon Carbide) 100 parts by mass, terpene phenol-based tackifier resin (softening point 125 ° C. (manufactured by Yasuhara Chemical Co.)), 10.5 parts by mass, epoxy-based crosslinking agent (N, N, N′N′-tetraglycidyl-m-) Xylenediamine) 0.12 parts by mass and 21 parts by mass of toluene were uniformly mixed and dissolved to prepare an adhesive layer forming coating solution. The adhesive layer-forming coating solution is coated on a 50 μm-thick polyethylene terephthalate sheet (base material) that has been subjected to silicon release treatment with a baker-type applicator and dried sufficiently at 100 ° C. A re-peelable pressure-sensitive adhesive sheet on which a 45 μm pressure-sensitive adhesive layer was formed was produced. Table 1 shows the measurement results of the physical property values and the property evaluation results of the removable pressure-sensitive adhesive sheet. In addition, the measuring method and evaluation method of various physical property values are shown below.

[Elastic modulus]: The elastic modulus (Pa) at room temperature (25 ° C.) of the pressure-sensitive adhesive layer (pressure-sensitive adhesive composition) constituting the removable pressure-sensitive adhesive sheet was measured. Specifically, a sample sheet having a thickness of 0.1 mm, a width of 3 mm, and a length of 15 mm is prepared by applying a pressure-sensitive adhesive composition as a sample onto a predetermined silicone sheet and then peeling it off. One end in the longitudinal direction of the sheet is supported by a fixed chuck, the other end is supported by a movable chuck, and each set temperature condition is determined by TMA tension mode method using TMA4000S (manufactured by MAC SCIENCE). It measured by applying a load of -0.2 to -0.5 g.

[Initial peeling force]: As an adherend, a SUS304 plate treated according to JIS Z 0237 was used, and a 20 mm wide adhesive sheet was attached to the surface thereof to prepare a sample. About this sample, 180 degree peeling force was measured at room temperature, and the obtained value was converted into the value (N / 25mm) at the time of using a 25 mm width removable adhesive sheet.

[Heat releasability (SUS)]: As an adherend, a SUS304 plate treated according to JIS Z 0237 was used, and a 100 × 100 mm pressure-sensitive adhesive sheet was attached to the surface, and then 120 ° C. (about Example 6). Only on a hot plate at 160 ° C. for 10 minutes. After cooling, whether or not the adhesive sheet was peeled off from the adherend at room temperature (25 ° C.) was evaluated according to the following criteria.
A: Peel from the adherend without applying any force.
○: After touching the adhesive layer with a finger, it peels off from the adherend.
(Triangle | delta): When force is applied to the adhesion layer, it peels without adhesive residue.
X: Even if force is applied to the pressure-sensitive adhesive layer, it does not peel easily, and adhesive residue is observed during peeling.

(Example 2)
Thermally expandable microspheres (F-50D (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.)) 9.5 parts by mass, acrylic adhesive (solid content = 35% by mass, Mw = 430,000, glass transition point = −36 ° C. (Harima Kasei) 100 parts by mass, xylene-based tackifier resin (softening point 170 ° C. (manufactured by Mitsubishi Gas Chemical)), 17.5 parts by mass, epoxy-based crosslinking agent (N, N, N′N′-tetraglycidyl-m) -Xylenediamine) 0.53 parts by mass and 21 parts by mass of toluene were uniformly mixed and dissolved to prepare an adhesive layer forming coating solution. A releasable pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that this pressure-sensitive adhesive layer-forming coating solution was used. Table 1 shows the measurement results of the physical property values and the property evaluation results of the removable pressure-sensitive adhesive sheet.

(Example 3)
9.4 parts by mass of thermally expandable microspheres (F-50D (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.)), acrylic adhesive (solid content 47% by mass, Mw = 480,000, glass transition temperature -34 ° C. (manufactured by one company) ) 100 parts by mass, terpene phenol-based tackifier resin (softening point 125 ° C. (manufactured by Yasuhara Chemical Co.)), 14.5 parts by mass, epoxy-based crosslinking agent (N, N, N′N′-tetraglycidyl-m-xylenediamine) 0.62 parts by mass and 21 parts by mass of toluene were uniformly mixed and dissolved to prepare an adhesive layer forming coating solution. A releasable pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that this pressure-sensitive adhesive layer-forming coating solution was used. Table 1 shows the measurement results of the physical property values and the property evaluation results of the removable pressure-sensitive adhesive sheet.

Example 4
A re-peelable pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that 0.36 parts by mass of isocyanate-based coronate L (manufactured by Nippon Polyurethane Industry Co., Ltd.) was used as a crosslinking agent. Table 1 shows the measurement results of the physical property values and the property evaluation results of the removable pressure-sensitive adhesive sheet.

(Example 5)
A detachable pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that 21 parts by mass of a rosin-based tackifying resin (softening point: 85 ° C. (manufactured by Harima Chemicals)) was used as the tackifying resin. Table 1 shows the measurement results of the physical property values and the property evaluation results of the removable pressure-sensitive adhesive sheet.

(Example 6)
A releasable pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that 8.3 parts by mass of F-100D (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) was used as the thermally expandable microsphere. Table 1 shows the measurement results of the physical property values and the property evaluation results of the removable pressure-sensitive adhesive sheet.

(Comparative Example 1)
A re-peelable pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that a polyethylene terephthalate sheet (without silicon release treatment) having a thickness of 100 μm was used as the substrate. Table 1 shows the measurement results of the physical property values and the property evaluation results of the removable pressure-sensitive adhesive sheet.

(Example 7)
The PI surfaces of two copper-clad laminates (CCL) (1F1 TM50 (manufactured by Toray Industries, Inc.)) were laminated on both sides of the adhesive layer of the releasable adhesive sheet obtained in Example 1, respectively. Next, a dry film is laminated on each copper foil surface of these copper-clad laminates, and then a predetermined circuit is processed and formed by exposure, development (1% sodium carbonate solution, 30 ° C. × 60 seconds), and etching ( A laminated body (processed adherend) was obtained by performing ferric chloride solution (45 ° C.) and resist stripping (2% NaOH solution, 45 ° C. × 60 seconds). About the obtained laminated body, heat peelability (CCL), contamination | pollution property (CCL), and productivity were evaluated. The results are shown in Table 2. In addition, the evaluation method of heat peelability (CCL), contamination (CCL), and productivity is shown below.

[Heat peelability (CCL)]: The laminate (processed adherend) was heated on a hot plate at 120 ° C. for 10 minutes. After cooling, whether or not the adhesive sheet was peeled off from the adherend at room temperature (25 ° C.) was evaluated according to the following criteria.
A: Peel from the adherend without applying any force.
○: After touching the adhesive layer with a finger, it peels off from the adherend.
(Triangle | delta): When force is applied to the adhesion layer, it peels without adhesive residue.
X: Even if force is applied to the pressure-sensitive adhesive layer, it does not peel easily, and adhesive residue is observed during peeling.

[Contamination (CCL)]: In the above-mentioned evaluation of “heat peelability (CCL)”, the contamination of the surface of the adherend from which the adhesive layer was peeled was evaluated according to the following criteria.
○: No discoloration or adhesive residue is observed on the adherend.
X: Discoloration or adhesive residue is observed on the adherend.

[Productivity]: The number of processed CCLs per unit time when the process of forming and processing a predetermined circuit by etching was made to flow at a speed of 1.5 m / min was calculated as the production amount. Productivity was evaluated by setting the case where the production amount was 50 sheets / hour as ◯ and the case where it was 25 sheets / hour as x. The CCL size was 350 mm × 250 mm.

(Example 8)
A laminate was obtained in the same manner as in Example 7 except that the removable pressure-sensitive adhesive sheet obtained in Example 2 was used. About the obtained laminated body, heat peelability (CCL), contamination | pollution property (CCL), and productivity were evaluated. The results are shown in Table 2.

(Comparative Example 2)
A laminate was obtained in the same manner as in Example 7 except that the releasable pressure-sensitive adhesive sheet obtained in Comparative Example 1 was used. About the obtained laminated body, heat peelability (CCL), contamination | pollution property (CCL), and productivity were evaluated. The results are shown in Table 2.

Example 9
A manufacturing jig made of SUS was attached to one surface of the pressure-sensitive adhesive layer of the releasable pressure-sensitive adhesive sheet obtained in Example 1. A laminated ceramic green sheet (filler: TiO ₂ , binder: PVB) was laminated on the other surface of the adhesive layer. Next, the multilayer ceramic green sheet was cut with a lifting blade while being heated to a temperature equal to or higher than the binder softening point of the multilayer ceramic green sheet (50 to 90 ° C.) to obtain a processed adherend. Then, it heated for 10 minutes on a 120 degreeC hotplate, and stood to cool to room temperature, Then, the adhesion layer was peeled and the ceramic capacitor fragmented was obtained. The processed adherend thus obtained was evaluated for heat peelability (green sheet) and contamination (green sheet). The results are shown in Table 2. Moreover, the evaluation method of heat peelability (green sheet) and contamination (green sheet) is shown below.

[Heat releasability (green sheet)]: The adherend (processed adherend) was heated on a hot plate at 120 ° C. for 10 minutes. After cooling, whether or not the adhesive layer was peeled off from the adherend at room temperature (25 ° C.) was evaluated according to the following criteria.
A: Peel from the adherend without applying any force.
○: After touching the adhesive layer with a finger, it peels off from the adherend.
(Triangle | delta): When force is applied to the adhesion layer, it peels without adhesive residue.
X: Even if force is applied to the pressure-sensitive adhesive layer, it does not peel easily, and adhesive residue is observed during peeling.

[Contamination (Green Sheet)]: In the above-mentioned evaluation of “heat-peelability (green sheet)”, the contamination of the surface of the adherend from which the adhesive layer was peeled was evaluated according to the following criteria.
○: No discoloration or adhesive residue is observed on the adherend.
X: Discoloration or adhesive residue is observed on the adherend.

(Example 10)
Polyimide films (25 μm) were laminated on both sides of the pressure-sensitive adhesive layer of the releasable pressure-sensitive adhesive sheet obtained in Example 1, respectively. Next, an electroless copper plating bath (copper sulfate (10 g / l), reducing agent, sodium hydroxide, chelating agent, additive) is formed to form a conductor having a thickness of 18 μm on the polyimide film, and the processed adherend Got. Then, it heated for 10 minutes on a 120 degreeC hotplate, and after standing_to_cool to room temperature, the adhesion layer was peeled and the two copper clad laminated boards were obtained. In addition, about the obtained processed to-be-adhered body, evaluation of heat peelability (polyimide) and chemical | medical solution penetration was performed. The results are shown in Table 2. Moreover, the evaluation method of heat peelability (polyimide) and chemical | medical solution penetration property is shown below.

[Heat releasability (polyimide)]: The processed adherend was heated on a hot plate at 120 ° C. for 10 minutes. After cooling, whether or not the adhesive layer was peeled off from the processed adherend at room temperature (25 ° C.) was evaluated according to the following criteria.
A: Peel from the processed adherend without applying any force.
○: After touching the adhesive layer with a finger, it is peeled off from the processed adherend.
(Triangle | delta): When force is applied to the adhesion layer, it peels without adhesive residue.
X: Even if force is applied to the pressure-sensitive adhesive sheet, it does not peel easily, and adhesive residue is observed at the time of peeling.

[Chemical solution soaking property]: In the above-mentioned evaluation of “heat peelability (polyimide)”, the chemical solution soaking property of the processed adherend from which the pressure-sensitive adhesive sheet was peeled was evaluated according to the following criteria.
○: No soaking of the chemical solution is observed at the interface between the processed adherend and the adhesive layer.
X: Smudge of the chemical solution is seen at the interface between the processed adherend and the adhesive layer.

  As shown in Table 1, the releasable pressure-sensitive adhesive sheets of Examples 1 to 6 have sufficient adhesion with the adherend before heating, while after heating, the processed adherend without any adhesive residue or resistance. It is clear that it can be peeled off. Moreover, if the releasable pressure-sensitive adhesive sheets of Examples 1 to 6 are used, the substrate can be peeled off and the adherend can be processed in a state of no substrate, which is superior to Comparative Example 1. It has excellent processability and is advantageous in terms of price, productivity, and environment.

  Further, as shown in Table 2, it is used as a backing sheet for FPC production (Examples 7 and 8), used as a temporary fixing sheet for cutting a multilayer ceramic green sheet (Example 9), and conductive. It is apparent that it can be suitably used for various adherend processing methods such as use as a masking sheet for body layer formation processing (Example 10). In addition, it can be confirmed that it is possible to process the adherend without the base material, and that it improves productivity by simultaneous processing on both sides and contributes to reduction in dimensional change by eliminating the influence of heat shrinkage of the base material. did it.

  The releasable pressure-sensitive adhesive sheet of the present invention is suitable as a backing sheet in a flexible printed circuit board (FPC) manufacturing process, a temporary fixing sheet in a cutting process of a semiconductor wafer, and a fragmentation process of a multilayer ceramic capacitor.

Claims (7)

Removability comprising a film-like or sheet-like base material, and an adhesive layer made of an adhesive composition containing thermally expandable microspheres and an adhesive, disposed on at least one surface of the base material An adhesive sheet,
The releasable pressure-sensitive adhesive sheet, wherein the surface of the base material on which the pressure-sensitive adhesive layer is disposed is a surface having peelability, and the base material is peelable from the pressure-sensitive adhesive layer under non-heating conditions. The releasable pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive composition has an elastic modulus at 25 ° C. of 1.0 × 10 ^{5 to} 7.0 × 10 ⁸ Pa.   The releasable pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the pressure-sensitive adhesive is an acrylic pressure-sensitive adhesive having in its molecular structure an active group capable of reacting with a crosslinking agent. The first adherend is adhered to the surface of the pressure-sensitive adhesive layer of the releasable pressure-sensitive adhesive sheet according to any one of claims 1 to 3, and the base material is peeled off under non-heating conditions to form the pressure-sensitive adhesive. Exposing the surface of the layer,
In a state where the second adherend is attached to the exposed surface of the pressure-sensitive adhesive layer, predetermined processing is performed on at least one of the first and second adherends,
Next, an adherend processing method including obtaining the processed adherend subjected to the predetermined processing by heating and peeling the adhesive layer.   The adherend processing method according to claim 4, wherein the predetermined processing is processing for manufacturing a flexible printed circuit board (FPC) including a step of patterning at least a predetermined conductor layer.   The adherend processing method according to claim 4, wherein the predetermined process is a cutting process.   The adherend processing method according to claim 4, wherein the predetermined processing is a conductor layer forming processing.