JP5778721B2 - Thermally peelable adhesive tape and method for cutting electronic parts - Google Patents

Description

  The present invention relates to a heat-peelable pressure-sensitive adhesive tape for fixing an electronic component during processing of the electronic component or the like.

In semiconductors and the like, wafers are becoming larger (450 mm) and thinner (100 μm or less), and the demand for compound semiconductors that require attention in handling LEDs and the like is greatly increasing.
Also, for processing electronic parts, it is possible to use a heat-peelable pressure-sensitive adhesive sheet that can be securely fixed during processing and can be easily peeled off after being processed by the loss of adhesive force. Widely done.
In recent years, electronic components have been reduced in size and precision, and processing accuracy is required more than ever. For example, ceramic capacitors are downsized from 1005 (1 mm × 0.5 mm) to 0603 (0.6 mm × 0.3 mm) and 0402 (0.4 mm × 0.2 mm).
Along with this, many chip jumps occur especially in the cutting process, which causes a decrease in yield. The cause of chip jumping includes vibration at the time of cutting and the like, and an adhesive sheet that can reliably hold the chip under such an environment is required.

  In addition, there is a method of adding a tackifier resin to an adhesive to increase the adhesive force during processing of a green sheet and the like, thereby increasing the retention of the workpiece to the adhesive. Therefore, by this method, the adhesion force was increased by adding a tackifying resin to suppress chip jump. However, although the chip skip frequency slightly decreased, it did not lead to a dramatic improvement. Furthermore, when tackifying resin was added and the adhesive force was increased, when the chip was peeled off, a sufficiently strong adhesive force remained in the pressure-sensitive adhesive layer, resulting in difficulty in peeling.

In order to eliminate such a phenomenon, means for cutting the green sheet using a peelable temporary fixing sheet that is not thermally expansible is known as described in Patent Document 1, and thermal expansibility is also disclosed. A heat-peelable pressure-sensitive adhesive sheet comprising a thermally expandable pressure-sensitive adhesive layer containing microspheres and layered silicate is also known as described in Patent Document 2.
However, these known means do not make the change rate of the probe tack value in a specific range, and the adhesive itself does not improve the holding characteristics of the chip during heating.
In the semiconductor field, the demand for compound semiconductors such as LEDs is growing rapidly. However, compound semiconductors are easily damaged by a slight impact, and careful attention is required during processing such as back grinding when thinning a wafer or dicing process when forming a chip.

JP 2012-52038 A JP 2008-266455 A

  The present invention is a pressure-sensitive adhesive tape that can sufficiently fix the chip even after cutting in the chip cutting process, and prevents chip skipping during cutting and improves the yield during chip cutting. It should be a challenge.

1. A heat-peelable pressure-sensitive adhesive tape having a heat-expandable pressure-sensitive adhesive layer, wherein the change rate of the probe tack value represented by Formula 1 of the heat-expandable pressure-sensitive adhesive layer is 19.0% or less .
W = | (B ₀ −B) / B ₀ × 100 | (Formula 1)
2. Adhesive strength of the thermally expandable pressure-sensitive adhesive layer at 23 ° C. when peeled at 23 ° C. for 30 minutes after being attached to a polyethylene terephthalate film (thickness: 25 μm) at 23 ° C. (peeling angle: 180 °, 2. The heat-peelable pressure-sensitive adhesive tape according to 1, wherein the tensile speed is 300 mm / min) is 2.5 N / 20 mm or more.
3. The heat-peelable pressure-sensitive adhesive tape according to 1 or 2, wherein the pressure-sensitive adhesive constituting the thermally expandable pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive.
4). The heat-peelable pressure-sensitive adhesive tape according to any one of 1 to 3, wherein the heat-expandable pressure-sensitive adhesive layer contains a tackifier resin.
5. 5. The heat-peelable pressure-sensitive adhesive tape according to 4, wherein the tackifying resin is a terpene phenol-based and / or rosin phenol-based resin.
The heat-peelable pressure-sensitive adhesive tape according to any one of 1 to 5, wherein the decrease rate of the total light transmittance after storage at 6.0 ° C for 1 week is 2% or less.
7). The heat-peelable pressure-sensitive adhesive tape according to any one of 1 to 6, wherein the heat-expandable pressure-sensitive adhesive layer contains a crosslinking agent.
8). The heat-peelable pressure-sensitive adhesive tape according to any one of 1 to 7, wherein a heat-expandable pressure-sensitive adhesive layer is directly formed on at least one side of the substrate.
9. The heat-peelable pressure-sensitive adhesive tape according to any one of 1 to 8, wherein a heat-expandable pressure-sensitive adhesive layer is formed on at least one side of the substrate via a rubbery organic elastic layer.
10. 10. The heat-peelable pressure-sensitive adhesive tape according to 9, wherein the rubbery organic elastic layer has a thickness of 3 to 200 μm.
11. The heat-peelable pressure-sensitive adhesive tape according to any one of 1 to 10, which is used when cutting an electronic component.
12. A method for cutting an electronic component using the heat-peelable pressure-sensitive adhesive tape according to any one of 12.1 to 11.

  According to the present invention, by using an adhesive tape comprising an adhesive layer made of an adhesive having a specific probe tack change rate, in the chip cutting step, the chips that are cut pieces do not fly, There exists an effect that it is being fixed to the adhesive layer surface of this adhesive tape.

Thermally peelable adhesive tape of the present invention

The inventors of the present invention have studied in detail to solve the above-mentioned problem, and by adding a small amount of tackifying resin to the thermally expandable pressure-sensitive adhesive layer to obtain a specific probe tack value change rate, chip skipping can be achieved. It has been found that there is something that is extremely effective in suppressing the above. In addition, it was also found that chip jumping varies greatly depending on the type of tackifying resin.
Such a phenomenon is considered to be caused by the compatibility between the pressure-sensitive adhesive and the tackifier resin.

FIG. 1 shows an example of the heat-peelable pressure-sensitive adhesive tape used in the present invention.
In this example, 1 is a supporting substrate, 2 is a thermally expandable pressure-sensitive adhesive layer, and 3 is a smooth peelable film (separator). Here, in the present invention, it is essential to have two thermally expandable pressure-sensitive adhesive layers, and 1 and 3 are optionally installed and may or may not be provided. The heat-peelable pressure-sensitive adhesive tape of the present invention will be described below.

(Base material)
In the present invention, the base material can be used as a support matrix of the heat-peelable pressure-sensitive adhesive tape. Examples of the base material include plastic base materials such as plastic films and sheets, non-woven fabrics, metal foils, rubber base materials such as paper, cloth and rubber sheets, foams such as foam sheets, and laminates thereof ( In particular, a suitable thin leaf body such as a laminate of a plastic base material and another base material or a laminate of plastic films (or sheets) can be used.
Moreover, it can be set as the heat peeling type adhesive tape which does not have a base material in this invention.

(Plastic base material)
Especially as a base material, plastic-type base materials, such as a plastic film and a sheet | seat, can be used conveniently. Although not particularly limited, in general, polyester films such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene- Olefins such as vinyl acetate copolymer (EVA) and other olefin resins containing α-olefin as a monomer component, polyamide (nylon), amide resins such as wholly aromatic polyamide (aramid), polyimide (PI) film, polyvinyl chloride ( PVC) film, polyphenylene sulfide (PPS) film, fluorine film, polyether ether ketone (PEEK) film, and the like. These materials can be used alone or in combination of two or more.

  Specific examples of polyethylene terephthalate (PET) films include polyethylene trays such as Toray Co., Ltd. “Lumirror”, Teijin DuPont Films Co., Ltd. “Teijin Tetron Film” “Melinex”, Mitsubishi Plastics Co., Ltd. “Diafoil”. As for phthalate (PEN) film, Teijin DuPont Films Co., Ltd. “Teonex” etc. As for polyimide (PI) film, Toray DuPont Co., Ltd. “Kapton”, Kaneka “Apical”, Ube Industries, Ltd. “ Polypropylene (PP) films such as Upilex, polyvinyl chloride (PVC) films such as Toray Industries, Inc. “Trephan”, Sun Tox Corporation “Santox”, Toyobo Co., Ltd. “Pyrene Film”, etc. Mitsubishi Plastics' “Altron”, Achilles “Achilles Type C +”, etc. (PE) film, such as Okura Kogyo Co., Ltd. “NSO”, polyphenylene sulfide (PPS) film, Toray Co., Ltd. “Torelina”, etc., fluorine film, Toray Co., Ltd. “Toyoflon”, DuPont Co., Ltd. ) “Tedlar film”. In addition, when a plastic-type base material is used as a base material, you may control deformability, such as elongation rate, by extending | stretching process etc.

(Nonwoven fabric)
As the nonwoven fabric, a nonwoven fabric made of natural fibers having heat resistance can be suitably used, and among these, a nonwoven fabric containing Manila hemp is suitable. Moreover, as a synthetic resin nonwoven fabric, a polypropylene resin nonwoven fabric, a polyethylene resin nonwoven fabric, an ester resin nonwoven fabric, etc. are mentioned, for example.

(Metal foil)
The metal foil is not particularly limited, and in addition to general metal foils such as copper foil, stainless steel foil, and aluminum foil, those made of various materials such as silver having a thickness, iron, an alloy of nickel and chromium are used. be able to.

(paper)
The paper is not particularly limited, but in general, Japanese paper, kraft paper, glassine paper, high quality paper, synthetic paper, top coat paper, and the like can be used.

  The thickness of the substrate can be appropriately selected according to the strength, flexibility, purpose of use, and the like. For example, it is generally 1000 μm or less (for example, 1 to 1000 μm), preferably 1 to 500 μm, more preferably 3 to 3 μm. Although it is 300 micrometers, Most preferably, it is about 5-250 micrometers, It is not limited to these. In addition, the base material may have a single layer form or may have a laminated form.

  In order to improve the adhesion of the surface of the base material with the heat-expandable pressure-sensitive adhesive layer 3 and the like, conventional surface treatments such as corona treatment, chromic acid treatment, ozone exposure, flame exposure, high piezoelectric impact exposure, ionizing radiation treatment, etc. These may be subjected to an oxidation treatment or the like by a chemical or physical method, or may be subjected to a coating treatment with a primer.

(Thermal expansion adhesive layer)
The heat-expandable pressure-sensitive adhesive layer 2 contains a pressure-sensitive adhesive having adhesiveness, and may further include heat-expandable microspheres for imparting heat-expandability. When heat-expandable microspheres are contained, after sticking the pressure-sensitive adhesive sheet to the adherend, the heat-expandable microspheres are foamed by heating the heat-expandable pressure-sensitive adhesive layer 2 at any time. By performing the expansion treatment, the adhesive area between the thermally expandable pressure-sensitive adhesive layer 2 and the adherend can be reduced, and the pressure-sensitive adhesive sheet can be easily peeled off.
The thickness of the thermally expandable pressure-sensitive adhesive layer 2 is about 3 to 300 μm, preferably about 5 to 150 μm, and more preferably about 10 to 100 μm.
A more preferable pressure-sensitive adhesive has a dynamic elastic modulus in a range of 5 kPa to 1 MPa at 25 ° C. to 150 ° C. in terms of a balance between an appropriate adhesive force before the heat treatment and a decrease in adhesive strength after the heat treatment. A pressure sensitive adhesive based on polymer.

  The pressure-sensitive adhesive constituting the heat-expandable pressure-sensitive adhesive layer 2 is preferably one that does not restrain the expansion and / or expansion of the heat-expandable microspheres as much as possible during heating. Examples of such adhesives include acrylic adhesives, rubber adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, and styrene-diene blocks. Copolymer-based pressure-sensitive adhesives, appropriate adhesives among known pressure-sensitive adhesives such as creep property-improving pressure-sensitive pressure-sensitive adhesives and radiation-curing pressure-sensitive pressure-sensitive adhesives in which a melting point of about 200 ° C. or less is blended with these pressure-sensitive adhesives It can be selected and used alone or in combination of two or more (see, for example, JP-A-56-61468, JP-A-63-17981, etc.).

  Of these, acrylic pressure-sensitive adhesives and rubber-based pressure-sensitive adhesives can be suitably used as the pressure-sensitive adhesive, and acrylic pressure-sensitive adhesives are particularly suitable. As an acrylic adhesive, an acrylic adhesive based on an acrylic polymer (homopolymer or copolymer) using one or more (meth) acrylic acid alkyl esters as monomer components. Agents. Examples of the (meth) acrylic acid alkyl ester in the acrylic pressure-sensitive adhesive include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and (meth) acrylic. Butyl acid, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, ( Octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, Undecyl (meth) acrylate, dodecyl (meth) acrylate, (meta Tridecyl acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, (meth) acrylic Examples thereof include (meth) acrylic acid alkyl esters having a linear or branched alkyl group having 1 to 20 carbon atoms in an alkyl group such as acid eicosyl. In the present specification, “(meth) acryl” means “acryl” and / or “methacryl”. Among these, (meth) acrylic acid alkyl esters having 4 to 18 carbon atoms in the alkyl group are more preferable. The content of the (meth) acrylic acid alkyl ester is preferably 50 to 100% by weight, more preferably 70 to 100% by weight, based on the total amount of monomer components (100% by weight) constituting the acrylic pressure-sensitive adhesive. .

  The acrylic polymer may be mixed with other monomer components copolymerizable with the (meth) acrylic acid alkyl ester as necessary for the purpose of modifying cohesion, heat resistance, crosslinkability, and the like. Corresponding units may be included. Examples of such monomer components include acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid and other carboxyl group-containing monomers; maleic anhydride, itaconic anhydride Acid anhydride monomers such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxyhexyl (meth) acrylate, hydroxyoctyl (meth) acrylate, (meth) Hydroxyl group-containing monomers such as hydroxydecyl acrylate, hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl methacrylate; styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylic Sulfonic acid group-containing monomers such as mid-2-methylpropanesulfonic acid, (meth) acrylamidepropanesulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalenesulfonic acid; (meth) acrylamide, N, N-dimethyl (N-substituted) amide monomers such as (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide; aminoethyl (meth) acrylate, (meta ) (Meth) acrylic acid aminoalkyl monomers such as N, N-dimethylaminoethyl acrylate, t-butylaminoethyl (meth) acrylate; methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, etc. (Meta) Acry Acid alkoxyalkyl monomers; maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide; N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N -Itacimide monomers such as octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide; N- (meth) acryloyloxymethylenesuccinimide, N- (meth) acryloyl-6-oxy Succinimide monomers such as hexamethylene succinimide and N- (meth) acryloyl-8-oxyoctamethylene succinimide; vinyl acetate, vinyl propionate, N-vinyl pyrrolide , Methyl vinyl pyrrolidone, vinyl pyridine, vinyl piperidone, vinyl pyrimidine, vinyl piperazine, vinyl pyrazine, vinyl pyrrole, vinyl imidazole, vinyl oxazole, vinyl morpholine, N-vinyl carboxylic acid amides, styrene, α-methyl styrene, N-vinyl Vinyl monomers such as caprolactam; Cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; Epoxy group-containing acrylic resin monomers such as glycidyl (meth) acrylate; Polyethylene glycol (meth) acrylate, Polypropylene glycol (meth) acrylate, Glycol acrylic ester monomers such as (meth) acrylic acid methoxyethylene glycol and (meth) acrylic acid methoxypolypropylene glycol; T) Acrylic acid ester monomers having heterocycles such as tetrahydrofurfuryl acrylate, fluorine (meth) acrylate, silicone (meth) acrylate, halogen atoms, silicon atoms, etc .; hexanediol di (meth) acrylate, (poly) ethylene Glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) Polyfunctional monomers such as acrylate, dipentaerythritol hexa (meth) acrylate, epoxy acrylate, polyester acrylate, urethane acrylate; isoprene, butadiene, Examples thereof include olefin monomers such as isobutylene; vinyl ether monomers such as vinyl ether. These monomer components can be used alone or in combination of two or more. Among the monomer components, a hydroxyl group-containing monomer or a carboxyl group-containing monomer is preferable from the viewpoint of improving cohesive force and crosslinkability, and hydroxyethyl (meth) acrylate or acrylic acid is more preferable. The content of the hydroxyl group-containing monomer is preferably less than 10% by weight, more preferably 8% by weight or less, particularly preferably based on the total amount of monomer components (100% by weight) constituting the acrylic polymer. 5% by weight or less. The content of the carboxyl group-containing monomer is preferably less than 20% by weight and more preferably 5% by weight or less with respect to the total amount of monomer components (100% by weight) constituting the acrylic pressure-sensitive adhesive.

  Rubber-based adhesives include natural rubber and various synthetic rubbers [for example, polyisoprene rubber, styrene / butadiene (SB) rubber, styrene / isoprene (SI) rubber, styrene / isoprene / styrene block copolymer (SIS). ) Rubber, Styrene / Butadiene / Styrene Block Copolymer (SBS) Rubber, Styrene / Ethylene / Butylene / Styrene Block Copolymer (SEBS) Rubber, Styrene / Ethylene / Propylene / Styrene Block Copolymer (SEPS) Rubber, Styrene -Ethylene / propylene block copolymer (SEP) rubber, recycled rubber, butyl rubber, polyisobutylene, and rubber-based pressure-sensitive adhesives based on these modified substances.

  In addition to the above-mentioned pressure-sensitive adhesive, the heat-expandable pressure-sensitive adhesive layer 2 includes a crosslinking agent, a tackifier resin, a pigment, a dye, a filler, an anti-aging agent, a conductive agent, an antistatic agent, an ultraviolet absorber, and a light stabilizer. Further, it may contain appropriate additives such as a release adjusting agent, a softening agent, a surfactant, a flame retardant, and an antioxidant.

(Crosslinking agent)
Examples of the crosslinking agent include isocyanate crosslinking agents, epoxy crosslinking agents, melamine crosslinking agents, peroxide crosslinking agents, urea crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salts. Examples of such crosslinking agents include siloxane-based crosslinking agents, carbodiimide-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, and amine-based crosslinking agents. An isocyanate-based crosslinking agent and an epoxy-based crosslinking agent can be suitably used.

(Isocyanate-based crosslinking agent)
Specific examples of the isocyanate-based crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate, Aromatic isocyanates such as 4-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct (trade name Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.), Trimethylolpropane / hexamethylene diisocyanate trimer adduct (trade name Coronate HL, manufactured by Nippon Polyurethane Industry Co., Ltd.), hexamethylene diisocyanate Door of the isocyanurate body (trade name: Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.), and the like isocyanate adducts, such as can be exemplified. These compounds may be used alone or in combination of two or more.
The blending amount of the isocyanate-based crosslinking agent may be appropriately determined according to the adhesive force to be controlled. Generally, it is blended in an amount of 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight per 100 parts by weight of the base polymer.

(Epoxy-based crosslinking agent)
Examples of the epoxy crosslinking agent include N, N, N ′, N′-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane (product name). “Tetrad C” manufactured by Mitsubishi Gas Chemical Co., Ltd.), 1,6-hexanediol diglycidyl ether (product name “Epolite 1600” manufactured by Kyoeisha Chemical Co., Ltd.), neopentyl glycol diglycidyl ether (product name “Epolite 1500NP”) Kyoeisha Chemical Co., Ltd.), ethylene glycol diglycidyl ether (product name “Epolite 40E” manufactured by Kyoeisha Chemical Co., Ltd.), propylene glycol diglycidyl ether (product name “Epolite 70P” manufactured by Kyoeisha Chemical Co., Ltd.), polyethylene glycol Diglycidyl ether (product name "Epiol E-400" manufactured by NOF Corporation), Ripropylene glycol diglycidyl ether (product name “Epiol P-200” manufactured by NOF Corporation), sorbitol polyglycidyl ether (product name “DENACOL EX-611” manufactured by Nagase ChemteX Corporation), glycerol polyglycidyl ether ( Product name “Denacol EX-314” manufactured by Nagase ChemteX Corp.), pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether (product name “Denacol EX-512” manufactured by Nagase ChemteX Corp.), sorbitan polyglycidyl ether , Trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, resorcin diglycidyl ether, bisphenol In addition to —S-diglycidyl ether, an epoxy resin having two or more epoxy groups in the molecule may be used. These crosslinking agents may be used alone or in combination of two or more.
The blending amount of the epoxy-based crosslinking agent may be appropriately determined according to controlling the adhesive force. Generally, 0.01 to 10 parts by weight, preferably 0.03 to 5 parts by weight, is blended per 100 parts by weight of the base polymer.

(Plasticizer)
The plasticizer used in the present invention is not particularly limited. For example, trimellitic acid ester plasticizer, pyromellitic acid ester plasticizer, polyester plasticizer, adipic acid plasticizer, and the like can be used. An acid ester plasticizer and a pyromellitic acid ester plasticizer can be preferably used. A plasticizer can be used individually or in combination of 2 or more types.
Specifically, trimellitic acid ester plasticizers include, for example, trimellitic acid tri (n-octyl), trimellitic acid tri (2-ethylhexyl), trimellitic acid triisooctyl, trimellitic acid triisononyl, And trimellitic acid trialkyl esters such as meritic acid triisodecyl. Examples of the pyromellitic acid ester plasticizer include pyromellitic acid tetraalkyl esters such as pyromellitic acid tetra (n-octyl) and pyromellitic acid tetra (2-ethylhexyl).
The amount of the plasticizer is appropriately determined depending on the purpose, but is 1 to 20 parts by weight, preferably 1 to 5 parts by weight per 100 parts by weight of the base polymer.

(Tackifying resin)
When selecting a tackifier resin, it is necessary to select a resin that is not compatible with the adhesive and that is excellent in compatibility.
When a tackifying resin that is poorly compatible with the pressure-sensitive adhesive is blended, the pressure-sensitive adhesive and the tackifying resin are separated not only in the compatible part where the pressure-sensitive adhesive and the tackifying resin are compatible. An incompatible part is formed. That is, a domain of a tackifying resin having a high glass transition temperature (Tg) is locally generated on the surface of the pressure-sensitive adhesive, and a surface having a partially low adhesive force is generated.
For this reason, on the surface where the domain portion of the tackifying resin with low adhesive strength is exposed, the micro member of the workpiece is bonded to the surface of the adhesive layer by weak adhesive strength. It is easy to peel off. This tendency becomes more prominent because the domain portion of the tackifier resin with respect to the size of the workpiece becomes larger as the workpiece after cutting becomes smaller.
For this reason, no matter how much the tackifying resin is increased to improve the adhesive strength, if the tackifying resin is not compatible with the adhesive, the adhesive strength should be referred to as the average value of the entire adhesive surface. Because of the physical properties, chip skipping due to variations in in-plane physical properties when the pressure-sensitive adhesive layer surface is viewed in a microscopic manner cannot be eliminated.

As tackifying resins used in the present invention, rosin resins derived from rosin, terpene resins derived from terpenes such as pinene, aliphatic hydrocarbon resins derived from petroleum fractions and aromatic hydrocarbon resins are used. Although possible, a terpene phenol-based resin or a rosin phenol-based resin tackifying resin copolymerized with a phenol group such as rosin phenol or terpene phenol is preferable. The molecular structure of rosin phenol, especially terpene phenol, is not sterically crowded, and the hydroxyl group of the phenol group and the ester group in the acrylic pressure-sensitive adhesive are likely to interact with each other, thereby improving compatibility.
Specific examples of tackifying resins that can be used include YS Polystar S145 manufactured by Yasuhara Chemical Co., Ltd. and Tamanol 901 manufactured by Arakawa Chemical Co., Ltd. as terpene phenol resins, and Sumitomo Bakelite Sumio Co., Ltd. as rosin phenol resins. Light resin PR-12603.
On the other hand, rosin ester resins are expected to have compatibility due to intermolecular interaction between ester groups contained in the structure and ester groups in the acrylic pressure-sensitive adhesive, but rosin ester resin compositions have an alicyclic structure. Therefore, it is sterically crowded as compared with terpene phenol resin and the like, and the influence of the interaction by the functional group is low.
Further, a hydroxyl value or an acid value can be used as an index of compatibility between the adhesive and the resin. In the case of a resin having a high hydroxyl group, interaction between the hydroxyl group and the ester group in the acrylic pressure-sensitive adhesive is expected. In the case of a resin having a high acid value, the ratio of the carboxyl group in the structure is high, and the ester in the acrylic pressure-sensitive adhesive is high. Since intermolecular interaction with the group is possible, compatibility is improved as a result. Even if the rosin ester-based resin having a sterically crowded structure has a high acid value or hydroxyl value, the probability of intermolecular interaction with the ester group in the acrylic pressure-sensitive adhesive increases, so the compatibility improves. For example, rosin ester resin Superester A115 manufactured by Arakawa Chemical Co., Ltd. can be used. The value of hydroxyl value expected to improve compatibility is 45 or more, more preferably 70 or more, or the value of acid value is 15 or more, more preferably 40 or more.
Moreover, generally the compounding quantity of tackifying resin is 5-100 weight part with respect to 100 weight part of base polymers which form a thermally expansible adhesive layer, Preferably it is 10-50 weight part.

(Thermally expandable microsphere)
The heat-expandable microsphere is not particularly limited, and can be appropriately selected from known heat-expandable microspheres, and can be used alone or in combination of two or more. Examples of thermally expandable microspheres include propane, propylene, butene, normal butane, isobutane, isopentane, neopentane, normal pentane, normal hexane, isohexane, heptane, octane, petroleum ether, methane halide, and tetraalkylsilane. It may be any microsphere in which a low-boiling liquid, azodicarbonamide that is thermally decomposed by heating, or the like, which easily gasifies and expands by heating, is encapsulated in an elastic shell.

  The shell-forming substance that forms thermally expandable microspheres is composed of, for example, a polymer of a monomer capable of radical polymerization. Examples of monomers include nitrile monomers such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethoxyacrylonitrile, fumaronitrile; acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid Carboxylic acid monomers such as: vinylidene chloride; vinyl acetate; methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, isobornyl (meth) ) (Meth) acrylic acid esters such as acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, β-carboxyethyl acrylate; styrene monomers such as styrene, α-methylstyrene, chlorostyrene; Examples include amide monomers such as amides, substituted acrylamides, methacrylamides, substituted methacrylamides, or any mixture thereof. However, in the present invention, they are composed of a hot-melt material or a material that is destroyed by thermal expansion. Good.

The shell-forming substance may be prepared by copolymerization with one or more substances, such as vinylidene chloride-methyl methacrylate-acrylonitrile copolymer, methyl methacrylate-acrylonitrile-methacrylonitrile copolymer, methyl methacrylate- Examples include acrylonitrile copolymers, acrylonitrile-methacrylonitrile-itaconic acid copolymers, and the like.
Thermally expandable microspheres can be produced by a conventional method such as a coacervation method or an interfacial polymerization method.

  Examples of such thermally expandable microspheres include “Matsumoto Microsphere” manufactured by Matsumoto Yushi Seiyaku Co., Ltd. (product names F-30, F-36LV, F-50, F-65, FN-100SS, FN-180SS). , F-190D, F-260D, F-2800D), "Expansel" (product name 053-40, 031-40, 920-40, 909-80, 930-120) manufactured by Nihon Philite Co., Ltd., Kureha "Daifoam" manufactured by Chemical Industry Co., Ltd. (Product names H750, H850, H1100, S2320D, S2640D, M330, M430, M520), "Advancel" manufactured by Sekisui Chemical Co., Ltd. (Product names EML101, EMH204, EHM301, There are also commercially available products such as EHM302, EHM303, EM304, EHM401, EM403, EM501).

  In the present invention, other than the above can be used as the thermally expandable microsphere. Examples of such thermally expandable microspheres include various inorganic foaming agents and organic foaming agents. Typical examples of the inorganic foaming agent include ammonium carbonate, ammonium hydrogen carbonate, sodium hydrogen carbonate, ammonium nitrite, sodium borohydride, various azides and the like. Representative examples of organic foaming agents include, for example, water; chlorofluorinated alkane compounds such as trichloromonofluoromethane and dichloromonofluoromethane; azobisisobutyronitrile, azodicarbonamide, and barium azodi. Azo compounds such as carboxylate; hydrazine compounds such as paratoluenesulfonyl hydrazide, diphenylsulfone-3,3′-disulfonyl hydrazide, 4,4′-oxybis (benzenesulfonyl hydrazide), allyl bis (sulfonyl hydrazide); p- Semicarbazide compounds such as toluylenesulfonyl semicarbazide and 4,4′-oxybis (benzenesulfonyl semicarbazide); triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole; N, N′-dinitrosope Data tetramine, N, N'-dimethyl -N, N'N-nitroso compounds such as dinitrosoterephthalamide, and the like.

Thermally expandable microspheres have an appropriate strength that does not rupture until the volume expansion coefficient is 5 times or more, especially 7 times or more, especially 10 times or more in order to efficiently reduce the adhesive force of the adhesive layer by heat treatment. Thermally expandable microspheres are preferred.
The amount of thermally expandable microspheres can be appropriately set according to the expansion ratio of the pressure-sensitive adhesive layer, the ability to lower the adhesive force, etc., but generally is 100 parts by weight of the base polymer that forms the heat-expandable pressure-sensitive adhesive layer 2. For example, it is 1-150 weight part, Preferably it is 10-130 weight part, More preferably, it is 25-100 weight part.

For the heat-expandable pressure-sensitive adhesive layer 2, for example, a coating liquid containing a pressure-sensitive adhesive and heat-expandable microspheres is prepared using a solvent as necessary, and this is formed on the support substrate 1 or the support substrate 1 in advance. A method of coating on the rubbery organic elastic layer shown below, coating the coating liquid on an appropriate separator (such as release paper) to form a thermally expandable pressure-sensitive adhesive layer, It can be formed by a conventional method such as a method of transferring (transferring) onto the rubbery organic elastic layer. At this time, the heat-expandable pressure-sensitive adhesive layer 2 may be either a single layer or a multilayer.
The heat treatment conditions for allowing the adhesive sheet to be easily peeled off from the adherend are such that the surface area of the adherend and the type of thermally expandable microspheres reduce the adhesion area. General conditions are 100 to 250 ° C., 1 to 90 seconds (hot plate or the like) or 5 to 15 minutes (hot air dryer or the like).

(Rubber organic elastic layer)
A rubber-like organic elastic layer is provided between the base material and the heat-expandable pressure-sensitive adhesive layer 2 in view of imparting deformability of the heat-peelable pressure-sensitive adhesive sheet and improving peelability after heating. The organic organic elastic layer is a layer provided as necessary, and is not necessarily provided. Thus, by providing the rubber-like organic elastic layer, when the heat-peelable pressure-sensitive adhesive sheet is adhered to the adherend (workpiece or the like) using the heat-expandable pressure-sensitive adhesive layer 2, the heat-peeling is performed. The surface of the thermally expandable pressure-sensitive adhesive layer 2 in the mold pressure-sensitive adhesive sheet can be made to follow the surface shape of the adherend satisfactorily to increase the adhesion area, and the heat-peelable pressure-sensitive adhesive sheet can be heated from the adherend. When peeling, the thermal expansion of the heat-expandable pressure-sensitive adhesive layer 2 can be controlled with high precision (with high accuracy), and the heat-expandable pressure-sensitive adhesive layer 2 can be expanded preferentially and uniformly in the thickness direction.
That is, the rubber-like organic elastic layer has a function of providing a large adhesion area by following the surface shape of the adherend when the heat peelable pressure sensitive adhesive sheet is adhered to the adherend, and the heat peelable pressure sensitive adhesive sheet. When the heat-expandable pressure-sensitive adhesive layer 2 is heated and foamed and / or expanded in order to release the adherend, thermal expansion is achieved by reducing the restriction of foaming and / or expansion in the surface direction of the heat-peelable pressure-sensitive adhesive sheet. The adhesive pressure-sensitive adhesive layer 2 can serve to promote the formation of an undele structure due to a three-dimensional structural change.

  The rubbery organic elastic layer is preferably provided on the base-side surface of the heat-expandable pressure-sensitive adhesive layer 2 in a form superimposed on the heat-expandable pressure-sensitive adhesive layer 2. The rubbery organic elastic layer can be provided other than between the base material and the thermally expandable pressure-sensitive adhesive layer 2. The rubbery organic elastic layer can be interposed on one side or both sides of the substrate.

  The rubbery organic elastic layer 2 can employ an adhesive layer, and the material thereof is not particularly limited, and the adhesive exemplified in the thermally expandable adhesive layer 2 is preferably used as a constituent material. Can do. Examples of the adhesive include acrylic adhesive, rubber adhesive, vinyl alkyl ether adhesive, silicone adhesive, polyester adhesive, polyamide adhesive, urethane adhesive, and styrene-diene block copolymer system. It can be appropriately selected from an adhesive, a creep property improving adhesive, a radiation curable adhesive, and the like.

  More specifically, for example, rubber adhesives based on natural rubber or synthetic rubber, methyl group, ethyl group, propyl group, butyl group, 2-ethylhexyl group, isooctyl group, isononyl group, isodecyl group, dodecyl Acrylic acid alkyl such as acrylic acid or methacrylic acid having an alkyl group having a carbon number of 20 or less, such as a group, lauryl group, tridecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group Ester, Acrylic acid, Methacrylic acid, Icotanic acid, Hydroxyethyl acrylate, Hydroxyethyl methacrylate, Hydroxypropyl acrylate, Hydroxypropyl methacrylate, N-methylolacrylamide, Acrylonitrile, Methacrylonitrile, Glyci acrylate Le, glycidyl methacrylate, vinyl acetate, styrene, isoprene, butadiene, isobutylene, and the like acrylic adhesive as a base polymer, an acrylic polymer mainly composed of vinyl ether.

  The rubbery organic elastic layer 2 can be formed of natural rubber, synthetic rubber, or synthetic resin having rubber elasticity in addition to the above-described pressure-sensitive adhesive. Examples of the synthetic resin include synthetic rubbers such as nitrile, diene, and acrylic resins; thermoplastic elastomers such as polyolefins and polyesters; ethylene-vinyl acetate copolymers, polyurethane, polybutadiene, soft polyvinyl chloride, and the like. And a synthetic resin having rubber elasticity. Even if it is essentially a hard polymer such as polyvinyl chloride, it can be used by developing rubber elasticity in combination with a compounding agent such as a plasticizer or a softener.

  Moreover, the rubber-like organic elastic layer 2 made of these materials is similar to the above-mentioned heat-expandable pressure-sensitive adhesive layer in that the pressure-sensitive adhesive and the synthetic resin are cross-linked, tackifying resin, plasticizer, filler, anti-aging An appropriate additive such as an agent may be blended.

  The formation of the rubbery organic elastic layer is, for example, a method of applying a coating liquid containing a constituent material of the rubbery organic elastic layer on the substrate 1 (coating method), a film made of the rubbery organic elastic layer forming material, or A method of adhering a laminated film in which a layer made of the rubber-like organic elastic layer forming material is previously formed on the thermally expandable pressure-sensitive adhesive layer 2 made of one or more layers to the substrate 1 (dry lamination method), It can be performed by an appropriate method such as a method of co-extruding a resin composition containing a constituent material and a resin composition containing the rubber-like organic elastic layer forming material (co-extrusion method).

  The rubbery organic elastic layer may be formed of a foam film or the like mainly composed of such components. Foaming is a conventional method, for example, a method using mechanical stirring, a method using a reaction product gas, a method using a foaming agent, a method for removing soluble substances, a method using a spray, a method for forming a syntactic foam, It can be performed by a sintering method or the like. The rubbery organic elastic layer may be a single layer or may be composed of two or more layers.

  The rubbery organic elastic layer has a thickness of 3 to 200 μm, preferably 5 to 100 μm. If it is in the range of 3 to 200 μm, the heat-peelable pressure-sensitive adhesive sheet follows the surface shape of the adherend and provides a large adhesion area without being too thin, and the heat-expandable pressure-sensitive adhesive layer 2 is three-dimensional. The function of promoting the formation of an eel structure by changing the structure can be expressed. Further, since it is not thicker than necessary, cohesive failure does not occur in the rubbery organic elastic layer after foaming.

(Adhesive layer)
In the heat-peelable pressure-sensitive adhesive tape of the present invention, when a heat-peelable pressure-sensitive adhesive layer containing thermally expandable microspheres is provided on one surface of the substrate, the other surface of the base is, for example, at least coated. In order to fix the object to be cut while fixing the object to be fixed such as cutting of the cut object, an adhesive layer for fixing the heat-peelable pressure-sensitive adhesive tape can be provided on a separately prepared base.
The adhesive layer at this time also needs to be stable against stimuli such as heat and vibration generated in processing such as cutting.
As the adhesive layer, for example, a material based on the resin used for the pressure-sensitive adhesive can be used.

(Separator)
A separator is used as a protective material for the surface (adhesive surface) of the thermally expandable pressure-sensitive adhesive layer 2 or the like. However, the separator can be used as necessary, and is not necessarily used. As a separator, both surfaces may be mold release surfaces, or only one surface (one surface) may be a mold release surface. The separator is peeled off when the pressure-sensitive adhesive layer protected by the separator is used.

As such a separator, a known or commonly used release paper can be used. Specifically, as the separator, for example, a substrate having a release agent layer such as a plastic film or paper surface-treated with a release agent such as silicone, long chain alkyl, fluorine, or molybdenum sulfide; polytetrafluoro A low-adhesive substrate made of a fluoropolymer such as ethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene / hexafluoropropylene copolymer, chlorofluoroethylene / vinylidene fluoride copolymer; A low-adhesive substrate made of a nonpolar polymer such as an olefin resin (for example, polyethylene, polypropylene, etc.) can be used. Of course, in the base material having the release agent layer, the release agent layer surface is the release surface, and in the low adhesive base material, the surface of the low adhesive substrate is the release surface.
The separator can be formed by a known or conventional method. Further, the thickness of the separator is not particularly limited.

(Change rate of probe tack value)
If it is a composition in which a tackifying resin is simply blended in an adhesive, the compatibility is originally good or bad, the optical properties of the adhesive, such as turbidity (haze), It can also be determined by the transmitted light intensity.
However, in the present invention, the heat-expandable microspheres are mixed in the pressure-sensitive adhesive layer, and in order to improve the convenience of the peelable pressure-sensitive adhesive tape, a dye or the like is added to the base material or the pressure-sensitive adhesive layer for visibility. Therefore, the change in the optical properties caused by the incompatibility is hidden by the change in the optical properties caused by these operations, and its recognition is extremely difficult.
Therefore, as a method for confirming the in-plane variation of the adhesive physical properties, it was decided to examine whether the compatibility was good or bad by measuring changes in the adhesive physical properties by the probe tack method. Furthermore, in order to ensure detection by the probe tack method, the examination was performed using a sample that was left at 0 ° C. for 1 week.
Compatibility is governed by thermodynamics and not by kinetics.
In other words, those having good compatibility remain good even after being allowed to stand at 0 ° C. for 1 week, but those having poor compatibility are more likely to be detected because the phase separation is further progressed. Thus, by leaving it at 0 ° C. for 1 week, it becomes clearer whether the compatibility is good.
Therefore, the probe tack value (B ₀ ) immediately after production of the heat-peelable adhesive tape and the probe tack value (B) after storage for 1 week at 0 ° C. are measured twice, and the measured values are compared. As a result, in the system in which the chip jumps frequently, the measured value significantly increased or decreased. That is, the change rate of the probe tack value obtained by the following formula (1) was large. On the other hand, when the change rate of the probe tack value is 19% or less, the effect of improving the tip jump is noticeable. In the case of the heat-peelable pressure-sensitive adhesive tape having a change rate of 15% or less, more preferably 10% or less, it is dramatic. As a result, the chip skipping phenomenon was suppressed. W = | (B ₀ −B) / B ₀ × 100 | Formula (1)
From the above, it is possible to confirm improvement in the adhesive physical properties using the change rate of the probe tack value as an index.

Similarly, in order to confirm the compatibility based on the total light transmitted light intensity, the total light transmitted light intensity A ₀ immediately after the production of the heat-peelable pressure-sensitive adhesive tape and the total light transmitted light after storage at 0 ° C. for one week. When the total light transmitted light intensity was measured twice with the intensity A and the measured values were compared, the measured value was remarkably reduced in the system in which the chip jump occurred frequently. That is, the decrease width of the total light transmitted light intensity obtained by the following formula (2) was large. On the other hand, when the total light transmitted light intensity decrease width is 3.0% or less, the effect of improving chip jumping is noticeable, more preferably 2.0% or less, and further preferably 1.5% or less. In the mold pressure-sensitive adhesive tape, the chip skip phenomenon has been remarkably suppressed.

  The heat-peelable pressure-sensitive adhesive tape of the present invention has a pressure-sensitive adhesive force of a thermally expandable pressure-sensitive adhesive layer at 23 ° C. when it is allowed to stand in a 23 ° C. atmosphere for 30 minutes after being attached to a polyethylene terephthalate film (thickness: 25 μm) at 23 ° C. (Peeling angle: 180 °, tensile speed: 300 mm / min) is preferably 2.5 N / 20 mm width or more. More preferably, the width is 2.5 N / 20 mm width to 20 N / 20 mm width, and further preferably 4.5 N / 20 mm width to 20 N / 20 mm width. When the adhesive strength in the 23 ° C. atmosphere is 2.5 N / 20 mm width or more, the adherend can be sufficiently retained, and the chip does not peel off during the cutting process.

(Usage method of the heat-peelable pressure-sensitive adhesive tape of the present invention)
The heat-peelable pressure-sensitive adhesive tape of the present invention is used as a pressure-sensitive adhesive sheet for fixing an electronic component on a substrate exclusively when the electronic component is cut.
The electronic parts to be cut are electronic parts such as capacitors, inductors, coils, resistors, piezoelectric elements, vibrators, LEDs, semiconductors, display devices, and the like, and are electronic parts cut by any means.
Such an electronic component is fixed on the substrate by an adhesive force through the heat-peelable adhesive tape of the present invention. Thereafter, the electronic component is cut by any means such as a push cutting means using a push cutting blade or a cutting method using a rotary blade, and then the heat-peelable pressure-sensitive adhesive tape of the present invention is heated to foam the thermally expandable pressure-sensitive adhesive layer. Thus, the adhesive force of the cut electronic component to the thermally expandable pressure-sensitive adhesive layer is reduced, and the cut electronic component is picked up.

(Probe tack measurement method)
Each heat-peelable adhesive sheet is cut into a size of width: 20 mm and length: 50 mm, and Nitto Denko double-sided adhesive tape No.531 is applied to a slide glass (76 mm x 26 mm) made by Matsunami Glass Industry Co., Ltd. The sample cut | disconnected from it was bonded together using the hand roller. Set on a probe tack measuring machine (trade name “TACKINESS TESTER Model TAC-II” manufactured by RHESCA) with the heat-expandable adhesive layer facing up, Immersion speed: 30mm / min, test speed: 30mm / min, preload : 100 gf, press time: 1.0 sec., Probe area: The value measured under the condition of 5 mmφcircle (SUS) is the probe tack value (N / 5 mmφ). The probe tack value immediately after sample preparation is B ₀ , the probe tack value after standing for 1 week at 0 ° C after the sample is prepared is B, and the change rate W (%) of the probe tack value after the acceleration test is B Calculation was performed according to equation (1). The measurement result of the increase / decrease rate of the probe tack value is shown in the “probe tack increase / decrease rate (%)” column of Table 1.
W = | (B ₀ −B) / B ₀ × 100 | Formula (1)

(0 ℃ storage method)
Each heat-peelable adhesive sheet is sealed in a plastic bag with a chuck, and then kept in a tank at a temperature of 0 ± 2 ° C for 168 ± 2 hours to prevent condensation, then temperature: 23 ± 2 ° C and humidity : Each measurement was performed for 1 hour in an atmosphere of 65 ± 5% RH.

(Adhesive strength measurement method)
Each heat-peelable pressure-sensitive adhesive sheet is cut into a size of width: 20 mm and length: 140 mm, and a polyethylene terephthalate film (trade name “Lumirror S-10”, manufactured by Toray Industries, Inc.) is applied to the thermally expandable pressure-sensitive adhesive layer. A thickness: 25 μm, a width: 20 mm) after being bonded according to JIS Z 0237 (2009) (specifically, under an atmosphere of temperature: 23 ± 2 ° C. and humidity: 65 ± 5% RH) 2 kg roller is reciprocated once and bonded together) and set in a tensile tester with a thermostatic bath set to 23 ° C. (trade name “Shimadzu Autograph AG-120kN” manufactured by Shimadzu Corporation) for 30 minutes put. After standing, the load when the adherend was peeled off from the heat-peelable pressure-sensitive adhesive sheet was measured at a temperature of 23 ° C. under the conditions of a peel angle of 180 ° and a peel speed (tensile speed) of 300 mm / min. Then, the maximum load at that time (the maximum value of the load excluding the peak top in the initial measurement) is obtained, and this maximum load is defined as the adhesive strength (N / 20 mm width) of the thermally expandable adhesive layer. The measurement results of the adhesive strength are shown in the column of “Adhesive strength (N / 20 mm)” in Table 1.

(Total light transmittance measurement method)
Each heat-peelable pressure-sensitive adhesive sheet was cut into a size of 30 mm in width and 30 mm in length, and the total light transmittance (%) was measured based on JIS K 7361 using a Haze Meter HM-150 manufactured by Murakami Color Science Laboratory. did. The value of total light transmittance (%) immediately after preparing the sample is A ₀ , the total light transmittance (%) after standing for 1 week at 0 ° C. after preparing the sample is A, and after the acceleration test The total light transmittance decrease rate V (%) was calculated according to the formula (2). The measurement result of the reduction rate of the total light transmittance is shown in the “total light transmittance decrease width (%)” column of Table 1.
V = total light transmittance increase / decrease rate (%), A ₀ = total light transmittance (%) before promotion immediately after the sample was produced, A = total light transmittance value (%) after promotion

(Measurement method of hydroxyl value)
The hydroxyl value of the sample was evaluated according to JIS K 0070-1992 (acetylation method). About 25 g of acetic anhydride was taken, pyridine was added to make the total volume 100 mL, and stirred well to prepare an acetylating reagent.
About 2 g of a sample was accurately weighed in a flat bottom flask, 5 mL of an acetylating reagent and 10 mL of pyridine were added, and an air cooling tube was attached. After heating at 100 ° C for 70 minutes, the mixture is allowed to cool, and 35 mL of toluene is added as a solvent from the top of the condenser and stirred, and then 1 mL of water is added and stirred to decompose acetic anhydride. To complete the decomposition, it was heated again for 10 minutes and allowed to cool.
The cooling tube was washed with 5 mL of ethanol and removed, and 50 mL of pyridine was added as a solvent and stirred. To this solution, 25 mL of 0.5 mol / L potassium hydroxide ethanol solution was added using a whole pipette, and potentiometric titration was performed with 0.5 mol / L potassium hydroxide ethanol solution, and the hydroxyl value was calculated from the following formula (3).
B: Amount of 0.5 mol / L potassium hydroxide ethanol solution used for the blank test (mL)
C: Amount of 0.5 mol / L potassium hydroxide ethanol solution used for the sample (mL)
f: Factor of 0.5 mol / L potassium hydroxide ethanol solution S: Amount of sample collected (g)
D: Acid value

The acid value of the sample was evaluated according to JIS K 0070-1992 potentiometric titration method. A phenolphthalein solution was added as an indicator to a solvent in which diethyl ether and ethanol were mixed at a volume ratio of 4: 1 and neutralized with a 0.1 mol / L potassium hydroxide ethanol solution. About 5 g of a sample was precisely weighed in a beaker, 50 mL of a solvent was added, and the mixture was completely stirred and dissolved on a panel heater (80 ° C.), followed by potentiometric titration with a 0.1 mol / L potassium hydroxide ethanol solution. The acid value was determined from the following formula (4).
B: Amount of 0.1 mol / L potassium hydroxide ethanol solution used for the sample (mL)
F: Factor of 0.1 mol / L potassium hydroxide ethanol solution S: Amount of sample collected (g)

Example 1
To 100 parts by weight of an acrylic copolymer (ethyl acrylate: 2-ethylhexyl acrylate: hydroxyethyl acrylate: methyl methacrylate = 70 parts by weight: 30 parts by weight: 5 parts by weight: 6 parts by weight) Polyurethane Industry Co., Ltd. Coronate L) 2 parts by weight was added, and toluene was added to prepare a uniformly mixed solution, which was applied on a 100 μm thick PET substrate so that the thickness after drying was 10 μm. (Rubber-like organic elastic layer).
In addition, 100 parts by weight of the above-mentioned acrylic copolymer, 2 parts by weight of an isocyanate-based crosslinking agent, terpene phenol tackifier resin (YShara Chemical Co., Ltd. YS Polystar S145, hydroxyl value 100 mgKOH / g, acid value 2 mgKOH / g) 30 A toluene solution prepared by blending 35 parts by weight of heat-expandable microspheres (Matsumoto Microsphere F-50 manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) with parts by weight is prepared and dried on a PET substrate separator (38 μm). Was applied so that the thickness of the film became 35 μm (thermally expandable pressure-sensitive adhesive layer 1).
After drying, a polyester film coated with a rubbery organic elastic layer was bonded to the rubbery organic elastic layer side to obtain a heat-peelable pressure-sensitive adhesive sheet 1 used in the present invention.

(Example 2)
100 parts by weight of the above acrylic copolymer, 2 parts by weight of an isocyanate-based crosslinking agent (Coronate L manufactured by Nippon Polyurethane Industry Co., Ltd.), a terpene phenol-based tackifier resin (Tamanol 901 manufactured by Arakawa Chemical Co., Ltd., hydroxyl value 45 mgKOH) / G, acid value 52 mg KOH / g) 30 parts by weight of a heat-expandable microsphere (Matsumoto Yushi Seiyaku Co., Ltd. Matsumoto Microsphere F-50) 35 parts by weight of toluene solution is prepared, PET It apply | coated so that the thickness after drying might be set to 35 micrometers on a base-material separator (38 micrometers) (thermally-expandable adhesive layer 2). Except for the above, a heat-peelable pressure-sensitive adhesive sheet 2 was obtained in the same manner as in Example 1.

(Example 3)
100 parts by weight of the above acrylic copolymer, 2 parts by weight of an isocyanate-based crosslinking agent (Coronate L manufactured by Nippon Polyurethane Industry Co., Ltd.), rosin phenol-based tackifier resin (Sumilite Resin PR-12603 manufactured by Sumitomo Bakelite, acid value) A toluene solution prepared by blending 30 parts by weight of 65 mg KOH / g) with 35 parts by weight of thermally expandable microspheres (Matsumoto Microsphere F-50 manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) was prepared, and a PET substrate separator (38 μm) was prepared. ) Was applied so that the thickness after drying was 35 μm (thermally expandable pressure-sensitive adhesive layer 3). Except for the above, a heat-peelable pressure-sensitive adhesive sheet 3 was obtained in the same manner as in Example 1.

Example 4
100 parts by weight of the above copolymer, 2 parts by weight of an isocyanate-based crosslinking agent (Coronate L manufactured by Nippon Polyurethane Industry Co., Ltd.), rosin ester-based tackifier resin (Superester A115 manufactured by Arakawa Chemical Co., Ltd.), hydroxyl value 25 mgKOH / g, acid value 18 mg KOH / g) 30 parts by weight of a toluene solution prepared by blending 35 parts by weight of thermally expandable microspheres (Matsumoto Microsphere F50 manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) It was applied on (38 μm) so that the thickness after drying was 35 μm (thermally expandable pressure-sensitive adhesive layer 4). Except for the above, a heat-peelable pressure-sensitive adhesive sheet 4 was obtained in the same manner as in Example 1.

(Example 5)
To 100 parts by weight of a copolymer consisting of ethyl acrylate-butyl acrylate-hydroxyethyl acrylate-acrylic acid-trimethylolpropane triacrylate (50 parts: 50 parts: 0.1 parts: 5 parts: 0.3 parts) 1 part by weight of an epoxy-based crosslinking agent (Tetrad C manufactured by Mitsubishi Gas Chemical Co., Ltd.), 20 parts by weight of a terpene phenol-based tackifier resin (YS Polystar S145 manufactured by Yasuhara Chemical Co., Ltd., hydroxyl value 100 mgKOH / g, acid value 2 mgKOH / g) A toluene solution containing 30 parts by weight of thermally expandable microspheres (Matsumoto Microsphere F50 manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) was prepared, and the thickness after drying on a PET substrate having a thickness of 100 μm was 35 μm. (Temporary fixing adhesive layer was applied) (thermally expandable adhesive layer 5). Except for the above, a heat-peelable pressure-sensitive adhesive sheet 5 was obtained in the same manner as in Example 1.

(Comparative Example 1)
To 100 parts by weight of the above copolymer, 2 parts by weight of an isocyanate-based crosslinking agent (Coronate L manufactured by Nippon Polyurethane Industry Co., Ltd.), rosin-based tackifier resin (Pencel D125 manufactured by Arakawa Chemical Co., Ltd.), hydroxyl value 40 mgKOH / g, A toluene solution prepared by blending 30 parts by weight of an acid value of 13 mg KOH / g with 35 parts by weight of thermally expandable microspheres (Matsumoto Microsphere F50 manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) was prepared, and a PET substrate separator (38 μm) was prepared. ) Was applied so that the thickness after drying was 35 μm (thermally expandable pressure-sensitive adhesive layer 6). Except for the above, a heat-peelable double-sided PSA sheet 6 was obtained in the same manner as in Example 1.

(inspection result)
(Evaluation method for cutting processability)
A laminated ceramic sheet ((* 1) 100 mm × 100 mm) obtained by the following method is bonded on the heat-expandable pressure-sensitive adhesive layer of each heat-peelable double-sided pressure-sensitive adhesive sheet 1 to 6, and it is attached and fixed to a dicing ring. A dicer is used to fully cut a chip having a size of 0402 (0.4 mm × 0.2 mm) (a cutting process is performed by dicing), and the presence or absence of chip peeling is visually confirmed during this cutting. At this time, ZH05-SD2000-N1-110-DD manufactured by DISCO Corporation was used as the dicing blade. When the feeding speed of the dicing blade is 70 mm / S and the rotational speed of the dicing blade is 50000 / s, all chips are adhered to the heat-peelable pressure-sensitive adhesive sheet. %. Therefore, the smaller the chip skip ratio, the better the chip skip prevention. The evaluation results of the chip skip prevention property are shown in the “chip skip ratio (%)” column of Table 1. The number of chips diced was C ₀ , the number of chips flew was C, and the chip flying ratio X was determined according to the equation (5).

<* 1 Multilayer ceramic sheet creation method>
Barium titanate (manufactured by Sakai Chemical Industry Co., Ltd .: trade name “BT-03 / high purity perovskite”) 100 parts by weight, polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd .: trade name “PVB”) 100 parts by weight (propylene Glycol monoethylene ether-dissolved product, 10% base), bis (2-ethylhexyl) phthalate (manufactured by Jplus Co., Ltd .: trade name “DOP”) 6 parts by weight, diglycerin oleate (manufactured by Riken Vitamin Co., Ltd .: product) 2 parts by weight of “Rikeale 0-71-D (E)”) and 80 parts by weight of toluene are stirred and mixed to prepare a coating solution for preparing a ceramic sheet. Next, the above coating solution is applied onto a separator coated with a silicone release agent on one side so that the thickness after drying is about 50 μm. After drying at 80 ° C. for 5 minutes, it is peeled off from the separator. To obtain a ceramic sheet. Ten ceramic sheets are laminated and pressed at a pressure of 300 kg / cm ² to obtain a laminated ceramic sheet.

In the pressure-sensitive adhesive sheets of the present invention (Examples 1 to 5), chip jumping was greatly suppressed during dicing, and in particular, in the compatible adhesive sheets (Examples 1 to 3 and 5), chip jumping did not occur at all.
In Comparative Example 1, a large number of chip jumps were confirmed. As this factor, it is presumed that since the compatibility is poor, a resin domain having a low adhesive strength is locally generated, and the adhesion between the chip and the adhesive sheet is greatly reduced.

DESCRIPTION OF SYMBOLS 1 ... Support base material 2 ... Thermal expansion adhesive layer 3 ... Separator

Claims (9)

A heat-peelable pressure-sensitive adhesive tape in which a heat-expandable pressure-sensitive adhesive layer containing an acrylic pressure-sensitive adhesive is formed, wherein the heat-expandable pressure-sensitive adhesive layer is a terpene phenol resin and / or a rosin phenol resin, and a hydroxyl group Containing a tackifying resin having a value of 45 to 100 mgKOH / g, the rate of change of the probe tack value represented by Formula 1 of the thermally expandable pressure-sensitive adhesive layer is 19.0% or less,
W = | (B ₀ −B) / B ₀ × 100 | (Formula 1)
(In Formula 1, W is the change rate of the probe tack value, B ₀ is the probe tack value of the heat-peelable adhesive tape, and B is the probe tack value after storage at 0 ° C. for 1 week.)
Adhesive strength of the thermally expandable pressure-sensitive adhesive layer at 23 ° C. when peeled at 23 ° C. for 30 minutes after being attached to a polyethylene terephthalate film (thickness: 25 μm) at 23 ° C. (Peeling angle: 180 °, tensile speed) : 300 mm / min) is a heat-peelable pressure-sensitive adhesive tape having 2.5 N / 20 mm or more. The heat-peelable pressure-sensitive adhesive tape according to claim 1, wherein the compounding amount of the tackifying resin is 10 to 50 parts by weight with respect to 100 parts by weight of the base polymer forming the thermally expandable pressure-sensitive adhesive layer. The heat-peelable pressure-sensitive adhesive tape according to claim 1 or 2 , wherein the decrease rate of the total light transmittance after storage at 0 ° C for 1 week is 2% or less. The heat-peelable pressure-sensitive adhesive tape according to claim 1 , wherein the heat-expandable pressure-sensitive adhesive layer contains a crosslinking agent. The heat-peelable pressure-sensitive adhesive tape according to any one of claims 1 to 4, wherein a heat-expandable pressure-sensitive adhesive layer is directly formed on at least one side of the substrate. The heat-peelable pressure-sensitive adhesive tape according to any one of claims 1 to 5 , wherein a heat-expandable pressure-sensitive adhesive layer is formed on at least one side of the substrate via a rubbery organic elastic layer. The heat-peelable pressure-sensitive adhesive tape according to claim 6 , wherein the rubber-like organic elastic layer has a thickness of 3 to 200 µm. The heat-peelable pressure-sensitive adhesive tape according to any one of claims 1 to 7 , which is used when cutting an electronic component. The cutting method of an electronic component using the heat peeling type adhesive tape in any one of Claims 1-8 .