JP2007238789A - Heating peeling off type adhesive sheet and manufacturing method for chip part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating peeling off type adhesive sheet capable of suppressing or preventing expansion at a temperature lower than a peeling off starting temperature by 10°C or more even if it has a heating peeling off type adhesion layer containing a thermally expandable fine ball. <P>SOLUTION: In the heating peeling off type adhesive sheet, a heating peeling off type adhesion layer containing the thermally expandable fine ball is provided on at least one surface of a base material, and the adhesive sheet is characterized in that a temperature difference of the peeling off starting temperature given by the heating peeling off type adhesion layer and the expansion starting temperature in the heating peeling off type adhesion layer is less than 10°C. As the thermally expandable fine ball contained in the heating peeling off type adhesion layer, the thermally expandable fine ball in which the expansion starting temperature is the temperature higher than the temperature lower than the peeling off starting temperature by 10°C and being not more than the peeling off starting temperature is preferable, and the thermally expandable fine ball obtained by classifying/removing the thermally expandable fine ball foamed or expanded by the heating treatment after the heating treatment is previously performed at the temperature lower than the peeling off starting temperature by 10°C can be preferably used. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat-peelable pressure-sensitive adhesive sheet and a method for producing a chip component. More specifically, the heat-peelable pressure-sensitive adhesive layer imparts even if it has a heat-peelable pressure-sensitive adhesive layer containing thermally expandable microspheres. The present invention relates to a heat-peelable pressure-sensitive adhesive sheet in which expansion at a temperature lower by 10 ° C. or more than a peeling start temperature is suppressed or prevented, and a chip component manufacturing method using the heat-peelable pressure-sensitive adhesive sheet.

  Conventionally, a heat-peelable pressure-sensitive adhesive sheet is known in which a pressure-sensitive adhesive layer (pressure-sensitive adhesive layer) containing a foaming agent (or expansion agent) such as thermally expandable microspheres is provided on at least one surface of a substrate (patent) Reference 1 to Patent Document 5). The heat-peelable pressure-sensitive adhesive sheet has both adhesiveness before heating and peelability after heating. Therefore, after the heat-peelable pressure-sensitive adhesive sheet achieves the purpose of bonding the article, the foaming agent-containing pressure-sensitive adhesive layer expands or expands by heating the pressure-sensitive adhesive layer (foaming agent-containing pressure-sensitive adhesive layer) containing the foaming agent. The surface of the foaming agent-containing pressure-sensitive adhesive layer changes to an uneven shape, thereby reducing the adhesion area with the adherend (article), and reducing the adhesion area reduces the adhesive force, allowing the adherend to be easily separated. In this way, it is used in a wide variety of applications such as temporary fixing during the manufacturing process of electronic parts and semiconductor chips, and logistics such as transportation.

  In recent years, electronic devices have become more sophisticated, smaller and lighter, and electronic components and semiconductor chips to be mounted have become more complex and smaller, and the manufacturing process has become diverse. In many cases, a process for heating the adherend is required.

  Heat-peelable pressure-sensitive adhesive sheets are also used in these electronic component and semiconductor chip manufacturing process applications. However, as described above, when a heating process is required for the adherend, a heat-peelable pressure-sensitive adhesive sheet is used during the heating process. It is important that the foaming agent-containing pressure-sensitive adhesive layer does not foam or peel, and holds the adherend firmly. However, the conventional heat-peelable pressure-sensitive adhesive sheet has variations in the individual expansion start temperatures (foaming start temperatures) of the thermally expandable microspheres as the foaming agent contained in the foaming agent-containing adhesive layer, and the foaming agent-containing adhesive layer In some cases, the thermally expandable microspheres expand or expand at a temperature 20 to 40 ° C. lower than the peeling start temperature imparted by. In particular, in a heat-peelable pressure-sensitive adhesive sheet that gives a peeling start temperature exceeding 150 ° C., there may be a temperature difference of about 50 ° C. at the maximum between the peeling start temperature and the expansion start temperature. Thus, due to foaming or expansion of thermally expandable microspheres below the temperature at which peeling does not occur originally, damage to the adherend such as cracking of the thinned semiconductor wafer, or peeling from the heat-peelable pressure-sensitive adhesive sheet May occur.

Japanese Utility Model Publication No. 50-13878 Japanese Patent Publication No.51-24534 JP-A-56-61468 JP-A-56-61469 JP 60-252681 A

Therefore, the object of the present invention is to expand at a temperature lower by 10 ° C. or more than the peeling start temperature imparted by the heat-peelable pressure-sensitive adhesive layer even if it has a heat-peelable pressure-sensitive adhesive layer containing thermally expandable microspheres. An object of the present invention is to provide a heat-peelable pressure-sensitive adhesive sheet that is suppressed or prevented, and a chip component manufacturing method using the heat-peelable pressure-sensitive adhesive sheet.
Another object of the present invention is to have a heat-peelable pressure-sensitive adhesive layer containing thermally expandable microspheres, and 10 times higher than the peeling start temperature provided by the heat-peelable pressure-sensitive adhesive layer during the processing of the adherend. A heat-peelable pressure-sensitive adhesive sheet that can effectively suppress or prevent damage to a workpiece or chip component even if heated at a temperature lower than or equal to ℃, and manufacture of a chip component using the heat-peelable pressure-sensitive adhesive sheet It is to provide a method.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that the temperature difference between the peeling start temperature imparted by the heat-peelable adhesive layer as the thermally expandable microsphere and the expansion start temperature in the heat-peelable adhesive layer. However, when a thermally expandable microsphere having a temperature of less than 10 ° C. is used, a heat-peelable pressure-sensitive adhesive sheet in which expansion at a temperature lower by 10 ° C. or more than the peeling start temperature imparted by the heat-peelable pressure-sensitive adhesive layer is suppressed or prevented It was found that it can be obtained. The present invention has been completed based on these findings.

  That is, the present invention is a heat-peelable pressure-sensitive adhesive sheet in which a heat-peelable pressure-sensitive adhesive layer containing thermally expandable microspheres is provided on at least one surface of a substrate, and the heat-peelable pressure-sensitive adhesive layer provides a peel There is provided a heat-peelable pressure-sensitive adhesive sheet, wherein a temperature difference between a start temperature and an expansion start temperature in a heat-peelable pressure-sensitive adhesive layer is less than 10 ° C.

  In the present invention, as the thermally expandable microspheres contained in the heat-peelable adhesive layer, the thermally expandable microspheres whose expansion start temperature is higher than the temperature lower by 10 ° C. than the start temperature of peeling and not higher than the start temperature of peeling. A sphere can be suitably used. As such thermally expandable microspheres, heat obtained by preliminarily heat-treating at a temperature 10 ° C. lower than the peeling start temperature, and then classifying and removing the thermally expandable microspheres foamed or expanded by the heat treatment. Inflatable microspheres are preferred.

  The heat-peelable pressure-sensitive adhesive sheet of the present invention may have a rubbery organic elastic layer between the substrate and the heat-peelable pressure-sensitive adhesive layer, and the rubbery organic elastic layer is made of an adhesive material. Preferably it is formed.

  The present invention is also a method for producing a chip component by cutting a workpiece using a heat-peelable pressure-sensitive adhesive sheet, wherein the workpiece is coated on the heat-peelable pressure-sensitive adhesive layer in the above-mentioned heat-peelable pressure-sensitive adhesive sheet. A chip component characterized by picking up a chip component obtained by cutting and processing a workpiece from a heat-peelable pressure-sensitive adhesive sheet after pasting the workpiece and cutting the workpiece. A manufacturing method is provided. In the chip component manufacturing method, electronic parts or electric parts can be suitably used as the workpiece.

  Since the heat-peelable pressure-sensitive adhesive sheet of the present invention has the above-described configuration, even if it has a heat-peelable pressure-sensitive adhesive layer containing thermally expandable microspheres, the peeling start temperature provided by the heat-peelable pressure-sensitive adhesive layer Expansion at a temperature lower by 10 ° C. or more than that is suppressed or prevented. Therefore, when manufacturing the chip component, if the heat-peelable pressure-sensitive adhesive sheet of the present invention is used, it has a heat-peelable pressure-sensitive adhesive layer containing thermally expandable microspheres, and during the processing of the adherend, Even if heated at a temperature lower by 10 ° C. or more than the peeling start temperature provided by the heat-peelable adhesive layer, damage to the workpiece or chip component can be effectively suppressed or prevented.

  Embodiments of the present invention will be described below in detail with reference to the drawings as necessary. In addition, the same code | symbol may be attached | subjected to the same member, a part, etc.

  The heat-peelable pressure-sensitive adhesive sheet of the present invention has at least a base material and a heat-peelable pressure-sensitive adhesive layer (thermally expandable pressure-sensitive adhesive layer) formed on at least one surface of the base material, and the heating While the peelable adhesive layer contains thermally expandable microspheres as a foaming agent, the temperature between the peeling start temperature imparted by the heat peelable adhesive layer and the expansion start temperature (foaming start temperature) in the heat peelable adhesive layer The difference is less than 10 ° C. Thus, in the heat-peelable pressure-sensitive adhesive sheet of the present invention, the temperature at which the expansion start temperature of the heat-peelable pressure-sensitive adhesive layer is lower by less than 10 ° C. than the temperature at which the heat-peelable pressure-sensitive adhesive layer imparts less than 10 ° C. And a temperature exceeding (peeling start temperature−10 ° C.)], so that when the adherend adhered on the heat-peelable pressure-sensitive adhesive layer is processed, heating is performed if the temperature is 10 ° C. or more lower than the peel start temperature. Even so, foaming or expansion of the heat-peelable pressure-sensitive adhesive layer can be suppressed or prevented.

  Here, “peeling start temperature” means the lowest heat treatment temperature at which the adhesive strength of the heat-peelable pressure-sensitive adhesive layer can be reduced to 10% or less before heating. Therefore, by measuring the lowest heat treatment temperature that can reduce the adhesive strength of the heat-peelable pressure-sensitive adhesive layer to 10% or less of the adhesive strength before heating, the peel start temperature applied to the heat-peelable pressure-sensitive adhesive layer is obtained. be able to. Specifically, a polyethylene terephthalate film with a width of 20 mm and a thickness of 25 μm [trade name “Lumirror S10 # 25” (manufactured by Toray Industries, Inc.); The test piece is prepared by sticking together with a hand roller so that bubbles do not enter. 30 minutes after bonding the PET film to the test piece, the PET film was peeled off at a 180 ° peeling angle, and the adhesive strength at that time (measurement temperature: 23 ° C., tensile speed: 300 mm / min, peeling angle) : 180 °), and the adhesive force is defined as “initial adhesive force”. In addition, the test piece produced by the above method is in a state where the hot plate set to each temperature (heat treatment temperature) is used to crush the metal plate (stainless steel plate, thickness of about 1 mm) preheated to each temperature. And then left at 23 ° C. for 2 hours, and then the PET film is peeled off at a peeling angle of 180 °. At that time, the adhesive force (measurement temperature: 23 ° C., tensile speed: 300 mm / min, peeling) (Angle: 180 °) is measured and the adhesive strength is defined as “adhesive strength after heat treatment”. Then, the lowest heat treatment temperature at which the adhesive strength after the heat treatment is 10% or less of the initial adhesive strength is obtained. This lowest heat treatment temperature is the peeling start temperature of the heat-peelable pressure-sensitive adhesive layer.

  Note that the peeling start temperature is the lowest heat treatment temperature at which the adhesive strength of the heat-peelable pressure-sensitive adhesive layer can be reduced to 10% or less of the adhesive strength before heating. The temperature at which the adherend adhered to the heat-peelable adhesive layer expands or expands and starts to peel naturally (that is, the adherend adhered to the heat-peelable adhesive layer naturally peels off) It is also possible to determine the peeling start temperature by measuring the lowest temperature.

  The “expansion start temperature” means a temperature at which the heat-peelable pressure-sensitive adhesive layer starts to expand or expand by heating. Accordingly, by measuring the temperature at which the heat-peelable pressure-sensitive adhesive layer starts to foam or expand, the expansion start temperature of the heat-peelable pressure-sensitive adhesive layer can be obtained. Specifically, the heat-peelable pressure-sensitive adhesive sheet is heated for 1 minute at each temperature on a hot plate set at each temperature (heat treatment temperature), and the state of foaming or expansion of the heat-peelable pressure-sensitive adhesive layer at that time Is observed with an optical microscope, and the lowest heat treatment temperature at which the heat-peelable pressure-sensitive adhesive layer foams or expands (that is, the temperature at which the heat-peelable pressure-sensitive adhesive layer begins to foam or expand) is determined. This lowest heat treatment temperature is the expansion start temperature of the heat-peelable adhesive layer.

  Fig.1 (a)-(b) is a schematic sectional drawing which shows partially the example of the heat-peelable adhesive sheet of this invention. 1A and 1B, 1a and 1b are respectively a heat-peelable pressure-sensitive adhesive sheet, 2 is a substrate, 3 is a heat-peelable pressure-sensitive adhesive layer, 4 is a rubber-like organic elastic layer, and 5 is a separator. . A heat-peelable pressure-sensitive adhesive sheet 1a shown in FIG. 1A includes a base material 2, a heat-peelable pressure-sensitive adhesive layer 3 formed on one surface of the base material 2, and the heat-peelable pressure-sensitive adhesive layer 3 It is comprised with the separator 5 formed on the top. Moreover, the heat-peelable pressure-sensitive adhesive sheet 1b shown in FIG. 1B includes a base material 2, a rubber-like organic elastic layer 4 formed on one surface of the base material 2, and the rubber-like organic elastic layer 4 The heat-peelable pressure-sensitive adhesive layer 3 formed on the top and a separator 5 formed on the heat-peelable pressure-sensitive adhesive layer 3 are further formed. The heat-peelable pressure-sensitive adhesive layer 3 in the heat-peelable pressure-sensitive adhesive sheet (1a, 1b) contains heat-expandable microspheres, the peeling start temperature provided by the heat-peelable pressure-sensitive adhesive layer 3, and the heat-peelable pressure-sensitive adhesive layer. The temperature difference from the expansion start temperature in the layer 3 is less than 10 ° C. That is, the heat-peelable pressure-sensitive adhesive sheet (1a, 1b) is configured such that the temperature difference between the peeling start temperature imparted by the heat-peelable pressure-sensitive adhesive layer 3 and the expansion start temperature in the heat-peelable pressure-sensitive adhesive layer 3 is less than 10 ° C. have.

[Heat peelable adhesive layer]
The heat-peelable pressure-sensitive adhesive layer (thermally expandable pressure-sensitive adhesive layer) contains heat-expandable microspheres, and the peeling start temperature provided by the heat-peelable pressure-sensitive adhesive layer and the expansion start temperature in the heat-peelable pressure-sensitive adhesive layer And the temperature difference is less than 10 ° C. In the heat-peelable pressure-sensitive adhesive layer, the heat-expandable microspheres are expanded or expanded by heating, and the releasability can be exhibited by the expansion or expansion of the heat-expandable microspheres. Therefore, as the heat-expandable microsphere, it is preferable to use a heat-expandable microsphere having an expansion start temperature (foaming start temperature) that is higher than a temperature lower by 10 ° C. than the peeling start temperature and not higher than the peeling start temperature. it can. It is important that the heat-peelable pressure-sensitive adhesive layer contains thermally expandable microspheres in such a content ratio that a predetermined peeling start temperature is exhibited. Thermally expandable microspheres can be used alone or in combination of two or more.

  Thermally expandable microspheres are usually produced by an industrial manufacturing method, such as the thickness of the shell material (shell) of the thermally expandable microsphere, the particle diameter of the thermally expandable microsphere, and the gas component contained in the shell. It is extremely difficult to produce a product with a constant or uniform pressure, etc., and the thickness of the shell material of the thermally expandable microsphere and the particle size of the thermally expandable microsphere itself vary. Has occurred. Therefore, industrially produced thermally expandable microspheres may have a variation from the average expansion start temperature of ± 10 ° C. or more (for example, the difference between the maximum and minimum expansion start temperatures is ± In some cases, it may contain 20 ° C. or more), and usually contains not a few thermally expandable microspheres whose expansion start temperature is 10 ° C. or more lower than the peeling start temperature. Therefore, the thermally expandable microsphere may be, for example, a thermally expandable microsphere prepared in such a form that the variation from the average expansion start temperature is less than ± 10 ° C. At the time of production, it is extremely difficult to industrially produce thermally expandable microspheres in such a form that the variation from the average expansion start temperature is less than ± 10 ° C.

  Therefore, as the thermally expandable microsphere, the variation from the average of the expansion start temperature when manufactured is ± 10 ° C. or more (that is, the heat at which the expansion start temperature is 10 ° C. or more lower than the peeling start temperature). (Including expansible microspheres), heat obtained by pre-heating at a temperature 10 ° C. lower than the peeling start temperature, and then classifying and removing thermally expansible microspheres foamed or expanded by the heat treatment Inflatable microspheres (sometimes referred to as “heated spheroid processing type thermally expandable microspheres”) are preferred. Thus, the heat-classifying type thermally expandable microspheres are thermally expandable microspheres that have not been foamed or expanded by heat treatment at a temperature 10 ° C. lower than the peeling start temperature, and therefore 10 ° C. from the peeling start temperature. Under such a low temperature, it does not foam or expand.

  It is important that the heat treatment for obtaining a heat classification treatment type thermally expandable microsphere is performed at a temperature 10 ° C. lower than the peeling start temperature. As a heat treatment method in such heat treatment, a method capable of uniformly applying temperature to the thermally expandable microspheres is preferable, and a general drying method [for example, a method using an infrared lamp, a hot plate is used. The method can be appropriately selected and used from among a method and a method using a dryer using hot air (such as a method using a box-type dryer or a fluidized bed dryer).

  The heating time during the heat treatment can be selected, for example, from the range of 1 to 20 minutes (preferably 2 to 10 minutes), and particularly preferably 3 to 8 minutes (particularly about 5 minutes). If the heating time during the heat treatment is too long, the thermally expandable microspheres themselves are altered, and the thermally expandable microspheres foamed or expanded by the heat treatment at a temperature 10 ° C. lower than the peeling start temperature are separated and removed. Even if the thermally expandable microspheres remaining after the separation and removal are obtained, the thermally expandable microspheres may expand or expand at a temperature 10 ° C. or more lower than the peeling start temperature. In this case, the obtained heat-expandable microspheres are again subjected to heat treatment at a temperature 10 ° C. lower than the peeling start temperature and at an appropriate time. Thermally expandable microspheres having the property of not expanding can be obtained.

  In the classification process performed after the heat treatment in order to obtain a heat classification treatment type thermally expandable microsphere, a thermally expandable microsphere (for example, by heat treatment) expanded or expanded to a predetermined size or more by the heat treatment. It is important that the method can classify only thermally expandable microspheres that have expanded 10 to 100 times. As a classification processing method in such classification processing, a classification method widely known conventionally (for example, a centrifugal wind type, a vibration sieve type, or the like) can be appropriately employed.

  In addition, the peeling start temperature given to the heat-peelable microspheres by the heat-expandable microspheres depends on the content ratio of the heat-expandable microspheres and the adhesive strength of the heat-peelable microspheres (adhesive strength before heat treatment). However, it usually corresponds to or approximates the average value of the expansion start temperature of each thermally expandable microsphere. The peeling start temperature to be applied to the heat-peelable pressure-sensitive adhesive layer in the heat-expandable microsphere is determined by using the heat-expandable microsphere as an active ingredient that imparts heat-expandability (heat-release property) to the pressure-sensitive adhesive layer (ie, foaming by heating) In a state where the adhesive strength is reduced to 10% or less of the adhesive strength before heating when expanded, the adhesive strength is measured at each temperature as described above in the state of being included in the pressure-sensitive adhesive layer. By doing so, it can be obtained.

  In the present invention, the heat-expandable microsphere is not particularly limited, and is appropriately selected from known heat-expandable microspheres (such as various inorganic heat-expandable microspheres and organic heat-expandable microspheres). Can do. As the thermally expandable microspheres, a microencapsulated foaming agent can be suitably used from the viewpoint of easy mixing operation. Examples of such thermally expandable microspheres include microspheres in which a material (thermally expandable material) that is easily gasified and expanded by heating, such as isobutane, propane, or pentane, is encapsulated in an elastic shell. Is mentioned. The shell is often formed of a hot-melt 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. Thermally expandable microspheres can be produced by a conventional method such as a coacervation method or an interfacial polymerization method. Examples of thermally expandable microspheres include commercial products such as “Matsumoto Microsphere” (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.).

  In the thermally expandable microspheres, the separation start temperature to be applied is the type of the thermally expandable substance (particularly the vaporization temperature), the type of substance forming the shell, the thickness of the shell, and the particle diameter of the thermally expandable microsphere. The temperature can be adjusted to an appropriate temperature.

  As the heat-expandable microsphere, in order to reduce the adhesive force of the heat-peelable adhesive layer efficiently and stably by heat treatment, the volume expansion coefficient is 5 times or more, especially 7 times or more, particularly 10 times or more. Thermally expandable microspheres having an appropriate strength that does not rupture until they are preferred.

  In the heat-peelable pressure-sensitive adhesive layer, the content ratio (mixing amount) of the heat-expandable microspheres can be appropriately set according to the expansion ratio of the heat-peelable pressure-sensitive adhesive layer, the decrease in adhesive strength, etc. , Suitably selected from the range of 1 to 150 parts by weight (preferably 10 to 130 parts by weight, more preferably 25 to 100 parts by weight) with respect to 100 parts by weight of the base polymer of the adhesive forming the heat-peelable adhesive layer. Can do.

  The particle diameter (average particle diameter) of the thermally expandable microspheres can be appropriately selected according to the thickness of the heat-peelable pressure-sensitive adhesive layer. The average particle diameter of the thermally expandable microspheres can be selected from a range of, for example, 100 μm or less (preferably 80 μm or less, more preferably 1 to 50 μm, particularly 1 to 30 μm).

  Since the heat-peelable pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer, it is important to contain at least a pressure-sensitive adhesive for imparting adhesiveness together with the thermally expandable microspheres for imparting thermal expansibility. As such a pressure-sensitive adhesive (pressure-sensitive adhesive), a pressure-sensitive adhesive that allows foaming and / or expansion of the heat-expandable microsphere when the heat-peelable pressure-sensitive adhesive layer is heated can be used. Those which do not restrain the expansion and / or expansion of the sphere as much as possible are preferable. An adhesive can be used individually or in combination of 2 or more types.

  The pressure-sensitive adhesive can be appropriately selected from known pressure-sensitive adhesives, and examples thereof include rubber-based pressure-sensitive adhesives, acrylic pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, vinyl alkyl ether-based pressure-sensitive adhesives, polyester-based pressure-sensitive adhesives, and polyamides. Known adhesives such as adhesives based on urethane, urethane, and fluorine, and adhesives with improved creep characteristics in which these adhesives are blended with a hot-melt resin having a melting point of about 200 ° C. or less (For example, see JP-A-56-61468, JP-A-61-174857, JP-A-63-17981, JP-A-56-13040, etc.). These pressure-sensitive adhesives can be used alone or in combination of two or more. In addition to the polymer component such as an adhesive component (base polymer), the adhesive is a cross-linking agent (for example, polyisocyanate, alkyl etherified melamine compound, etc.), a tackifier, depending on the type of the adhesive. (For example, rosin derivative resin, polyterpene resin, petroleum resin, oil-soluble phenol resin, etc., solid, semi-solid or liquid at room temperature), including appropriate additives such as plasticizer, filler, anti-aging agent May be. The pressure-sensitive adhesive may be any form of pressure-sensitive adhesive such as an emulsion-based pressure-sensitive adhesive or a solvent-based pressure-sensitive adhesive.

  As the pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive or an acrylic pressure-sensitive adhesive is preferable, and an acrylic pressure-sensitive adhesive can be particularly preferably used.

  Rubber adhesives include natural rubber and various synthetic rubbers [for example, polyisoprene rubber, styrene / butadiene block copolymer (SB) rubber, styrene / isoprene block copolymer (SI) rubber, styrene / isoprene / styrene. Block copolymer (SIS) rubber, styrene / butadiene / styrene block copolymer (SBS) rubber, styrene / isoprene / butadiene / styrene block copolymer (SIBS) 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 modified products thereof As the base polymer They include rubber-based adhesives.

The acrylic pressure-sensitive adhesive is an acrylic polymer [homopolymer (homopolymer) or copolymer (copolymer)] using one or more (meth) acrylic acid alkyl esters as monomer components. ] As the base polymer. 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 include (meth) acrylic acid C _1-20 alkyl ester [preferably (meth) acrylic acid C _4-18 alkyl (linear or branched alkyl) ester] such as eicosyl acid.

  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 carboxyl group-containing monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and carboxyethyl acrylate; acid anhydrides such as maleic anhydride and itaconic anhydride Physical group-containing monomers; hydroxyl group-containing monomers such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, (N-substituted or unsubstituted) amide monomers such as N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide; vinyl ester monomers such as vinyl acetate and vinyl propionate Styling Styrene monomers such as α-methylstyrene; vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate Olefin or diene monomer such as ethylene, propylene, isoprene, butadiene and isobutylene; aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, etc. (Substituted or unsubstituted) amino group-containing monomers; (meth) acrylic acid alkoxyalkyl monomers such as (meth) acrylic acid methoxyethyl and (meth) acrylic acid ethoxyethyl; N-vinylpyrrolidone, N -Methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N -Monomers having a nitrogen atom-containing ring such as vinylcaprolactam; N-vinylcarboxylic acid amides; Monomers containing sulfonic acid groups such as styrene sulfonic acid, allyl sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate A phosphate group-containing monomer such as 2-hydroxyethylacryloyl phosphate; a maleimide monomer such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide; N Itacimide monomers such as methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide; N- ( Succinimide monomers such as (meth) acryloyloxymethylene succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide, N- (meth) acryloyl-8-oxyoctamethylene succinimide; polyethylene glycol (meth) acrylate, (meta ) Glycol-based acrylic ester monomers such as polypropylene glycol acrylate; Monomers having an oxygen atom-containing heterocycle such as tetrahydrofurfuryl (meth) acrylate; Fluorine Acrylic acid ester monomer containing fluorine atom such as (meth) acrylate; Acrylic acid ester monomer containing silicon atom such as silicone (meth) acrylate; 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) acrylate, Dipentaerythritol hexa (meth) acrylate, epoxy acrylate, polyester acrylate, urethane acrylate, divinylbenzene, butyl di (meth) acrylate, hexyl And polyfunctional monomers such as di (meth) acrylate. These monomer components can be used alone or in combination of two or more.

  The heat-peelable pressure-sensitive adhesive layer is formed, for example, by a conventional method of forming a sheet-like layer by mixing a pressure-sensitive adhesive, thermally expandable microspheres, and, if necessary, a solvent or other additive. be able to. Specifically, for example, a method of applying a mixture containing a pressure-sensitive adhesive, thermally expandable microspheres, and, if necessary, a solvent and other additives onto a substrate or a rubbery organic elastic layer described later, By applying the mixture on a separator (such as release paper) to form a heat-peelable pressure-sensitive adhesive layer and transferring (transferring) the mixture onto a base material or rubber-like organic elastic layer. A layer can be formed. The heat-peelable pressure-sensitive adhesive layer may be a single layer or a multilayer.

  The thickness of the heat-peelable pressure-sensitive adhesive layer can be appropriately selected depending on the reduction of adhesive strength, and can be selected from a range of 500 μm or less, preferably 300 μm or less (more preferably 100 μm or less). is there. If the thickness of the heat-peelable pressure-sensitive adhesive layer is too thick (excessive), the heat-peelable pressure-sensitive adhesive layer is liable to cohesive failure after expansion or foaming by the heat treatment, and the adherend (adhered material) is peeled off after peeling. In some cases, adhesive residue (residue of adhesive component) that causes contamination may occur. On the other hand, if the thickness of the heat-peelable pressure-sensitive adhesive layer is too thin (too small), the degree of deformation of the heat-peelable pressure-sensitive adhesive layer due to heat treatment is small and the adhesive force is not easily lowered, and the heat to be added It becomes necessary to make the particle size of the expandable microspheres too small. Therefore, the thickness of the heat-peelable pressure-sensitive adhesive layer is preferably 5 μm or more (preferably 10 μm or more, more preferably 15 μm or more). Of course, it is important that the thickness of the heat-peelable pressure-sensitive adhesive layer is thicker than the maximum particle size of the thermally expandable microspheres contained therein.

[Base material]
The substrate can be used as a support matrix such as a heat-peelable pressure-sensitive adhesive layer. In addition, the base material may have any form of the form of a single layer or the laminated form.

  Examples of the base material include paper base materials such as paper; fiber base materials such as cloth, non-woven fabric, felt, and net; metal base materials such as metal foil and metal plate; plastic base materials such as plastic films and sheets. Base materials: Rubber base materials such as rubber sheets; Foams such as foam sheets, and laminates thereof [particularly, laminates of plastic base materials and other base materials, or plastic films (or sheets) An appropriate thin leaf body such as a laminate and the like] can be used. As a base material, what is excellent in the heat resistance which does not melt at the heat processing temperature of a heat peeling type adhesion layer is preferable from points, such as the handleability after a heating. As the substrate, a plastic substrate such as a plastic film or sheet can be suitably used. Examples of the material in such a plastic material include olefins containing α-olefin as a monomer component such as polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), and the like. Resin: Polyester such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT); polyvinyl chloride (PVC); polyphenylene sulfide (PPS); polyamide (nylon), wholly aromatic polyamide (aramid) Amide resins such as polyether ether ketone (PEEK) and the like. These materials can be used alone or in combination of two or more.

  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.

  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.

  The surface of the substrate is chemically or physically treated by conventional surface treatments such as chromic acid treatment, ozone exposure, flame exposure, high piezoelectric impact exposure, ionizing radiation treatment, etc., in order to improve adhesion to the heat-peelable adhesive layer. An oxidation treatment or the like may be performed by a conventional method, or a coating treatment or the like by a primer may be performed. Moreover, in order to provide peelability with a heat-peelable pressure-sensitive adhesive layer or the like, for example, a coating treatment with a release agent such as a silicone resin or a fluorine resin may be performed.

  In the present invention, the heat-peelable pressure-sensitive adhesive layer can be provided on at least one surface (one surface or both surfaces) of the base material, and the base material can be embedded in the heat-peelable pressure-sensitive adhesive layer. .

[Separator]
In the present invention, a conventional release paper or the like can be used as the separator. The separator is used as a protective material for the heat-peelable pressure-sensitive adhesive layer, and is peeled off when the heat-peelable pressure-sensitive adhesive sheet is attached to an adherend. The separator is not necessarily provided.

  As the separator, for example, a substrate having a release layer such as a plastic film or paper surface-treated with a release agent such as silicone, long chain alkyl, fluorine, molybdenum sulfide; polytetrafluoroethylene, polychlorotrifluoro Low adhesion substrate made of fluorine-based polymer such as ethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene / hexafluoropropylene copolymer, chlorofluoroethylene / vinylidene fluoride copolymer; olefin resin (for example, A low-adhesive substrate made of a nonpolar polymer such as polyethylene or polypropylene can be used. In addition, a separator can also be used as a base material for supporting a heat-peelable pressure-sensitive adhesive layer.

  The separator can be formed by a known or common method. Further, the thickness of the separator is not particularly limited.

[Middle layer]
In the present invention, one or more intermediate layers may be provided between the substrate and the heat-peelable pressure-sensitive adhesive layer. Examples of the intermediate layer include a release agent coating layer for the purpose of imparting peelability and an undercoat coating layer for the purpose of improving adhesion. Examples of the intermediate layer other than the release agent coating layer and the undercoat coating layer include, for example, a layer for imparting good deformability, a layer for increasing the adhesion area to the adherend, and adhesion. From the layer for the purpose of improving the force, the layer for the purpose of following the surface shape of the adherend satisfactorily, the layer for the purpose of improving the process of reducing the adhesive strength by heating, and the adherend after heating And a layer for the purpose of improving the peelability.

  In particular, as a layer (intermediate layer) between the base material and the heat-peelable pressure-sensitive adhesive layer, for example, rubbery organic elasticity, from the viewpoint of imparting the deformability of the heat-peelable pressure-sensitive adhesive sheet or improving the peelability after heating. A layer can be provided. By providing a rubber-like organic elastic layer, the surface of the heat-peelable pressure-sensitive adhesive sheet (the surface of the heat-peelable pressure-sensitive adhesive layer) is changed to the surface shape of the adherend when the heat-peelable pressure-sensitive adhesive sheet is bonded to the adherend. The adhesion area can be increased by following it well, and when the heat-peelable pressure-sensitive adhesive sheet is heat-separated from the adherend, the thermal expansion of the heat-peelable pressure-sensitive adhesive layer is highly controlled (accurately). In addition, the heat-peelable pressure-sensitive adhesive layer can be preferentially and uniformly expanded in the thickness direction. The rubber-like organic elastic layer is a layer provided as necessary, and is not necessarily provided.

  The rubber-like organic elastic layer is preferably provided in a form superposed on the heat-peelable pressure-sensitive adhesive layer on the surface of the heat-peelable pressure-sensitive adhesive layer on the substrate side. In addition, it can provide also as layers other than the intermediate | middle layer between a base material and a heat peeling type adhesion layer. The rubbery organic elastic layer can be interposed on one side or both sides of the substrate.

  The rubbery organic elastic layer is preferably formed of natural rubber, synthetic rubber or synthetic resin having rubber elasticity, for example, having a D-type Sure D-type hardness based on ASTM D-2240 of 50 or less, particularly 40 or less.

  Examples of the synthetic rubber or the synthetic resin having rubber elasticity include nitrile-based, diene-based, and acrylic-based synthetic rubbers; polyolefin-based and polyester-based thermoplastic elastomers; ethylene-vinyl acetate copolymer, polyurethane, polybutadiene, and the like. And a synthetic resin having rubber elasticity such as soft polyvinyl chloride. Even if it is essentially a hard polymer such as polyvinyl chloride, rubber elasticity can be manifested in combination with compounding agents such as plasticizers and softeners. Such a composition can also be used as a constituent material of the rubbery organic elastic layer. Moreover, an adhesive substance such as an adhesive constituting the heat-peelable adhesive layer can be preferably used as a constituent material of the rubbery organic elastic layer.

  The rubber-like organic elastic layer is, for example, a method in which a coating liquid containing a rubber-like organic elastic layer forming material such as natural rubber, synthetic rubber or synthetic resin having rubber elasticity is applied on a substrate (coating method), the rubber A method of adhering a film made of a layered organic elastic layer forming material or a laminated film in which a layer made of the rubbery organic elastic layer forming material is previously formed on one or more heat-peelable adhesive layers (dry laminating method) ), A resin composition containing the constituent material of the substrate and a resin composition containing the rubber-like organic elastic layer forming material can be formed by a forming method such as a method (coextrusion method).

  The thickness of the rubbery organic elastic layer is generally 500 μm or less (for example, 1 to 500 μm), preferably 3 to 300 μm, and more preferably about 5 to 150 μm. The rubbery organic elastic layer may be a single layer or may be composed of two or more layers.

  The rubbery organic elastic layer may be formed of an adhesive substance mainly composed of natural rubber, synthetic rubber, or synthetic resin having rubber elasticity, and is formed of a foam film or the like mainly composed of such a component. May be. 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.

[Other adhesive layers]
In the present invention, in the heat-peelable pressure-sensitive adhesive sheet, when the heat-peelable pressure-sensitive adhesive layer is formed only on one surface (one surface) of the base material, the other pressure-sensitive adhesive layer is formed on the other surface of the base material. May be. Using the other adhesive layer, it can be attached and supported on a support such as a support base. The pressure-sensitive adhesive for forming such another pressure-sensitive adhesive layer is not particularly limited, and pressure-sensitive adhesives exemplified as the pressure-sensitive adhesive used in the heat-peelable pressure-sensitive adhesive layer (for example, rubber-based pressure-sensitive adhesive, acrylic pressure-sensitive adhesive) Adhesives, silicone pressure-sensitive adhesives, vinyl alkyl ether pressure-sensitive adhesives, polyester-based pressure-sensitive adhesives, polyamide-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, fluorine-based pressure-sensitive adhesives, creep property improving pressure-sensitive adhesives, etc.) An adhesive can be used. These pressure-sensitive adhesives can be used alone or in combination of two or more.

  In addition, as thickness of another adhesion layer, 500 micrometers or less (for example, 5-500 micrometers, Preferably it is 10-300 micrometers, More preferably, it is 15-100 micrometers) may be sufficient. In the formation of the other adhesive layer, the same method as that for the heat-peelable adhesive layer (for example, a method of coating on a substrate, coating on a separator to form an adhesive layer, and then applying this onto the substrate. A transfer method) can be used. The other adhesive layer may be either a single layer or multiple layers.

  The heat-peelable pressure-sensitive adhesive sheet of the present invention can be produced by forming a heat-peelable pressure-sensitive adhesive layer on a substrate via another layer (such as a rubbery organic elastic layer) as necessary. The heat-peelable pressure-sensitive adhesive sheet may have a form having an adhesive face only on one side, or may have a form having adhesive faces on both sides. The heat-peelable pressure-sensitive adhesive sheet can have a form such as a sheet form or a tape form.

  Even if the heat-peelable pressure-sensitive adhesive sheet of the present invention is heated at a temperature 10 ° C. or more lower than a predetermined peel-off start temperature, foaming or expansion of the heat-peelable pressure-sensitive adhesive layer is suppressed or prevented. When the adherend is processed with the adherend adhered on the mold adhesive layer, the adherend is adhered to an extremely thin or heat-peelable adhesive sheet. Even if it is subjected to thin processing in a wet state, the heat-peelable pressure-sensitive adhesive layer is foamed and / or expanded on the adherend even if heated at a temperature lower by 10 ° C. or more than the peeling start temperature. And the adherend can be securely held on the heat-peelable adhesive layer. Then, with the adherend adhered on the heat-peelable adhesive layer, the heat-peelable pressure-sensitive adhesive sheet (especially the heat-peelable pressure-sensitive adhesive layer) is heated to a peeling start temperature or higher at any time. As a result, the heat-expandable microspheres in the heat-peelable pressure-sensitive adhesive layer foam or expand, and the heat-peelable pressure-sensitive adhesive layer foams or expands. The surface (adhesive surface) of the layer is deformed into an uneven shape, and the adhesion area between the adhesive surface and the adherend is reduced, whereby the adhesion between the adhesive surface deformed into the uneven shape and the adherend is reduced. The force decreases, and the adherend adhered to the pressure-sensitive adhesive surface can be peeled from the heat-peelable pressure-sensitive adhesive sheet.

  Therefore, the heat-peelable pressure-sensitive adhesive sheet of the present invention is particularly suitable for heat-peelable pressure-sensitive adhesive sheets used in the manufacture of small chip components (for example, electronic components such as semiconductor capacitors and semiconductor chips, ceramic capacitors, and oscillators). It can be suitably used as a heat-peelable pressure-sensitive adhesive sheet used in a small chip forming step.

[Adherent]
In the present invention, an article (an adherend or a workpiece) to be adhered and held by the heat-peelable pressure-sensitive adhesive sheet can be arbitrarily selected. Specifically, the adherend (workpiece) includes electronic parts such as semiconductor wafers and semiconductor chips; electrical articles such as ceramic capacitors and oscillators; display devices such as liquid crystal cells, Various articles, such as a thermal head, a solar cell, and a printed circuit board, are mentioned. An adherend may be individual or may be combined 2 or more types.

  The heat-peelable pressure-sensitive adhesive sheet of the present invention is, for example, an adherend (workpiece) even when it is heated at a temperature 10 ° C. or more lower than the peeling start temperature provided by the heat-peelable pressure-sensitive adhesive layer during processing. Thus, the adherend can be bonded with a strong adhesive force without damaging the substrate, and after processing, the bonded state can be released quickly. That is, when the heat-peelable pressure-sensitive adhesive sheet is used, it can be easily and quickly peeled after processing, and the manufacturing workability can be greatly improved. In addition, as a processing method of such a to-be-adhered body, it can select arbitrarily, For example, processes, such as a grinding | polishing process, a dicing process, a pattern formation process, an assembly process, are mentioned.

  Moreover, the heat-peelable pressure-sensitive adhesive sheet of the present invention can also be suitably used as a protective material when transporting the adherend.

  In the present invention, after a work piece (work piece) is adhered as an adherend to the heat-peelable pressure-sensitive adhesive sheet, various processed products can be obtained by processing. For example, when electronic parts such as a semiconductor wafer are used as the workpiece, an electronic part such as a semiconductor chip or a circuit board can be obtained as a processed product. That is, in this invention, an electronic component and a circuit board can be manufactured using the said heat peeling type adhesive sheet.

  The heat treatment for peeling the heat-peelable pressure-sensitive adhesive sheet from the adherend can be performed using appropriate heating means such as a hot plate, a hot air dryer, a near infrared lamp, and an air dryer. The heating temperature may be equal to or higher than the peeling start temperature provided by the heat-peelable pressure-sensitive adhesive layer, but the condition of the heat treatment is a reduction in the adhesion area due to the surface state of the adherend and the type of thermally expandable microspheres, It can be set as appropriate depending on the heat resistance of the substrate and adherend, the heating method (heat capacity, heating means, etc.), and the like. General heat treatment conditions are a temperature of 100 to 250 ° C. and a time of 5 to 90 seconds (hot plate or the like) or 5 to 15 minutes (hot air dryer or the like). Under such heating conditions, typically, the heat-expandable microspheres in the heat-peelable pressure-sensitive adhesive layer expand and / or foam, and the heat-peelable pressure-sensitive adhesive layer expands and deforms, resulting in uneven deformation, and the adhesive force is reduced or lost. . Note that the heat treatment can be performed at an appropriate stage depending on the purpose of use. In some cases, an infrared lamp or heated water can be used as the heating source.

[Chip parts manufacturing method]
The chip component manufacturing method of the present invention is a method of manufacturing a chip component by cutting a workpiece using a heat-peelable pressure-sensitive adhesive sheet, and the heat-peelable pressure-sensitive adhesive layer in the above-mentioned heat-peelable pressure-sensitive adhesive sheet. It is characterized by picking up a chip part obtained by cutting a workpiece from the heat-peelable pressure-sensitive adhesive sheet after pasting the workpiece on the workpiece and cutting the workpiece. . That is, in the method for manufacturing a chip part of the present invention, as the heat-peelable pressure-sensitive adhesive sheet, a heat-peelable pressure-sensitive adhesive layer containing thermally expandable microspheres is provided on at least one surface of the substrate, and the heat-peelable pressure-sensitive adhesive sheet. It is important to use a heat-peelable pressure-sensitive adhesive sheet in which the temperature difference between the peeling start temperature imparted by the layer and the expansion start temperature in the heat-peelable pressure-sensitive adhesive layer is less than 10 ° C. In this way, since the heat-peelable pressure-sensitive adhesive sheet is used, at the time of processing the workpiece when manufacturing the chip component, at a temperature lower by 10 ° C. or more than the peeling start temperature provided by the heat-peelable pressure-sensitive adhesive layer. Even if heated, damage to the workpiece or chip component can be effectively suppressed or prevented.

  In the chip component manufacturing method of the present invention, electronic parts or electric parts can be suitably used as the workpiece. Examples of such electronic components and electrical components include those exemplified above. In the present invention, a semiconductor wafer can be particularly preferably used as the workpiece. Accordingly, the chip component manufacturing method of the present invention is a method for manufacturing a semiconductor chip by subjecting a semiconductor wafer to singulation cutting using a heat-peelable pressure-sensitive adhesive sheet. A semiconductor wafer is bonded onto the heat-peelable adhesive layer in Step 1, and after the semiconductor wafer is cut into pieces, the semiconductor chip obtained by the piece-cut process is picked up from the heat-peelable adhesive sheet. A method of manufacturing a semiconductor chip is included.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1
The product name “Matsumoto Microsphere F-100D” (manufactured by Matsumoto Yushi Seiyaku Co., Ltd .; average particle size 12.5 μm; sometimes referred to as “thermally expandable microsphere A”) as hot expandable microspheres is dried with hot air. In the machine, heat treatment is carried out at 160 ° C. for 5 minutes to foam or expand in advance, and the foamed or expanded large particles are classified and removed using a centrifugal air classifier. An average particle diameter of 12.5 μm; sometimes referred to as “classified thermally expandable microsphere B” was obtained.

  Next, acrylic copolymer (acrylic copolymer having 2-ethylhexyl acrylate: 30 parts by weight, ethyl acrylate: 70 parts by weight, and methyl methacrylate: 5 parts by weight as monomer components): 100 parts by weight On the other hand, an isocyanate-based crosslinking agent (trade name “Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd.): A toluene solution containing a pressure-sensitive adhesive having a composition in which 1 part by weight is blended is prepared. Was applied to one surface of a polyester film (thickness: 100 μm) so that the thickness after drying or curing was 20 μm to obtain a rubbery organic elastic layer.

  Further, acrylic copolymer (acrylic copolymer having 2-ethylhexyl acrylate: 30 parts by weight, ethyl acrylate: 70 parts by weight, and methyl methacrylate: 5 parts by weight as monomer components): 100 parts by weight An isocyanate-based cross-linking agent (trade name “Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd.): 1 part by weight and classified thermally expandable microspheres B: containing thermally expandable microspheres having a composition of 30 parts by weight A toluene solution containing a pressure-sensitive adhesive was prepared, and the toluene solution was applied on a separator so that the thickness after drying or curing was 30 μm to obtain a heat-peelable pressure-sensitive adhesive layer. A peelable adhesive layer is bonded to the rubbery organic elastic layer, and a heat peelable adhesive sheet having a layer structure of “base material / rubbery organic elastic layer / heatable peelable adhesive layer” (“heat peelable” Was obtained sometimes referred to as type pressure-sensitive adhesive sheet A "). The heat-peelable pressure-sensitive adhesive layer in the heat-peelable pressure-sensitive adhesive sheet A contains classified thermally expandable microspheres B.

(Comparative Example 1)
“Substrate / rubber-like organic elastic layer / heat-peelable pressure-sensitive adhesive layer” in the same manner as in Example 1 except that the thermally expandable microsphere A was used in place of the classified thermally expandable microsphere B. A heat-peelable pressure-sensitive adhesive sheet having a layer structure (sometimes referred to as “heat-peelable pressure-sensitive adhesive sheet B”) was obtained.

  That is, a rubbery organic elastic layer was obtained in the same manner as in Example 1. Further, acrylic copolymer (acrylic copolymer having 2-ethylhexyl acrylate: 30 parts by weight, ethyl acrylate: 70 parts by weight, and methyl methacrylate: 5 parts by weight as monomer components): 100 parts by weight In addition, an isocyanate-based crosslinking agent (trade name “Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd.): 1 part by weight, and thermally expandable microsphere A: 30 parts by weight of thermally expandable microsphere-containing pressure-sensitive property After preparing a toluene solution containing an adhesive and applying the toluene solution on a separator so that the thickness after drying or curing is 30 μm to obtain a heat-peelable adhesive layer, the heat-peelable mold The pressure-sensitive adhesive layer was bonded to the rubbery organic elastic layer to obtain a heat-peelable pressure-sensitive adhesive sheet B. The heat-peelable pressure-sensitive adhesive layer in the heat-peelable pressure-sensitive adhesive sheet B contains thermally expandable microspheres A. The thermally expandable microsphere A is a thermally expandable microsphere that has not been subjected to a treatment for classifying large particles after being heated at 160 ° C. for 5 minutes, like the classified thermally expandable microsphere B.

(Comparative Example 2)
Thermally expandable microspheres A (trade name “Matsumoto Microsphere F-100D”, manufactured by Matsumoto Yushi Seiyaku Co., Ltd .; average particle size of 12.5 μm) as a thermally expandable microsphere is 1 at 160 ° C. in a hot air dryer. Thermally expandable microspheres (average particle diameter: 12.5 μm; average particle diameter: 12.5 μm; “thermal expansion property”). May be referred to as “microsphere C”).

  “Substrate / rubber-like organic elastic layer / heat-peelable pressure-sensitive adhesive layer” in the same manner as in Example 1 except that the thermally expandable microsphere C was used in place of the classified thermally expandable microsphere B. A heat-peelable pressure-sensitive adhesive sheet having a layer structure (sometimes referred to as “heat-peelable pressure-sensitive adhesive sheet C”) was obtained.

  That is, a rubbery organic elastic layer was obtained in the same manner as in Example 1. Further, acrylic copolymer (acrylic copolymer having 2-ethylhexyl acrylate: 30 parts by weight, ethyl acrylate: 70 parts by weight, and methyl methacrylate: 5 parts by weight as monomer components): 100 parts by weight In addition, an isocyanate-based crosslinking agent (trade name “Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd.): 1 part by weight, and thermally expandable microsphere C: 30 parts by weight of thermally expandable microsphere-containing pressure sensitive After preparing a toluene solution containing an adhesive and applying the toluene solution on a separator so that the thickness after drying or curing is 30 μm to obtain a heat-peelable adhesive layer, the heat-peelable mold The pressure-sensitive adhesive layer was bonded to the rubbery organic elastic layer to obtain a heat-peelable pressure-sensitive adhesive sheet C. The heat-peelable pressure-sensitive adhesive layer in the heat-peelable pressure-sensitive adhesive sheet C contains thermally expandable microspheres C. As described above, the heat-expandable microsphere C is a heat-expandable microsphere that has been heated at 160 ° C. for 1 hour and then subjected to a treatment for classifying large particles.

(Evaluation)
Each heat-peelable pressure-sensitive adhesive sheet obtained in Example 1 and Comparative Examples 1 and 2 was heated for 1 minute at each temperature (120 ° C, 130 ° C, 140 ° C, 150 ° C, 160 ° C, 170 ° C) on a hot plate. The state of foaming and / or expansion of the heat-peelable pressure-sensitive adhesive sheet when heated was observed with an optical microscope. The evaluation results are shown in the “foamed state” column of Table 1.

  Further, each heat-peelable pressure-sensitive adhesive sheet was bonded to a SUS304BA plate and allowed to stand at room temperature (23 ° C.) for 24 hours to prepare a heat-peelable evaluation sample. And each heat peeling type evaluation sample is heated for 1 minute at each temperature (120 degreeC, 130 degreeC, 140 degreeC, 150 degreeC, 160 degreeC, 170 degreeC) with a hotplate, and foaming thru | or expansion | swelling at that time Whether it peeled was observed visually. The evaluation results are shown in the column of “peeled state” in Table 1.

  In Table 1, “foaming start” indicates that the heat-peelable adhesive layer started to foam or expand at that temperature. In addition, “peeling start” means that at that temperature, the stainless steel plate (SUS304BA plate) bonded to the heat-peelable pressure-sensitive adhesive layer began to peel naturally from the foamed or expanded heat-peelable pressure-sensitive adhesive layer. Show.

  From Table 1, the heat-peelable pressure-sensitive adhesive sheet A according to Example 1 does not cause foaming or expansion of the heat-peelable pressure-sensitive adhesive layer at a temperature of 160 ° C. or less, and starts foaming or expansion at 170 ° C. At 0 ° C., peeling of the adherend is also starting to occur. That is, in the heat-peelable pressure-sensitive adhesive sheet A, the temperature difference between the expansion start temperature and the peel start temperature is less than 10 ° C.

  On the other hand, in the heat-peelable pressure-sensitive adhesive sheet B according to Comparative Example 1, foaming or expansion of the heat-peelable pressure-sensitive adhesive layer occurs at 120 ° C., and the adherend begins to peel at 170 ° C. That is, in the heat-peelable pressure-sensitive adhesive sheet B, the temperature difference between the expansion start temperature and the peel start temperature is 50 ° C. or more. In the heat-peelable pressure-sensitive adhesive sheet C according to Comparative Example 2, foaming or expansion of the heat-peelable pressure-sensitive adhesive layer occurs at 150 ° C., and the adherend begins to peel at 160 ° C. That is, in the heat-peelable pressure-sensitive adhesive sheet C, the temperature difference between the expansion start temperature and the peel start temperature is 10 ° C. or more. Moreover, the heat-peelable pressure-sensitive adhesive sheet C has a peeling start temperature of 160 ° C., which is lowered from the original 170 ° C. to 160 ° C.

It is a schematic sectional drawing which shows the example of the heat peeling type adhesive sheet of this invention partially.

Explanation of symbols

1a, 1b Heat-peelable adhesive sheet 2 Base material 3 Heat-peelable adhesive layer (thermally expandable adhesive layer)
4 Rubbery organic elastic layer 5 Separator

Claims (7)

  A heat-peelable pressure-sensitive adhesive sheet in which a heat-peelable pressure-sensitive adhesive layer containing thermally expandable microspheres is provided on at least one surface of a substrate, the heat-peelable pressure-sensitive adhesive layer providing a peeling start temperature, and heat-peeling A heat-peelable pressure-sensitive adhesive sheet, wherein the temperature difference from the expansion start temperature in the mold pressure-sensitive adhesive layer is less than 10 ° C.   The heat-expandable microsphere contained in the heat-peelable pressure-sensitive adhesive layer is a heat-expandable microsphere having an expansion start temperature that is higher than a temperature lower by 10 ° C. than the start temperature of release and lower than or equal to the start temperature of release. The heat-peelable pressure-sensitive adhesive sheet as described.   Thermally expandable microspheres obtained by preliminarily heat-treating the thermally expandable microspheres at a temperature 10 ° C. lower than the peeling start temperature, and then removing the thermally expandable microspheres foamed or expanded by the heat treatment by classification treatment. The heat-peelable pressure-sensitive adhesive sheet according to claim 1 or 2.   The heat-peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 3, further comprising a rubbery organic elastic layer between the substrate and the heat-peelable pressure-sensitive adhesive layer.   The heat-peelable pressure-sensitive adhesive sheet according to claim 4, wherein the rubber-like organic elastic layer is formed of an adhesive substance.   A method for producing a chip component by cutting a workpiece using a heat-peelable pressure-sensitive adhesive sheet, wherein the heat-peelable die in the heat-peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 5 After pasting the work piece on the adhesive layer and cutting the work piece, the chip part obtained by cutting the work piece is picked up from the heat-peelable pressure-sensitive adhesive sheet. A method for manufacturing a chip component.   The method of manufacturing a chip part according to claim 6, wherein the workpiece is an electronic system part or an electrical system part.

Images