TW202323476A - Thermal release adhesive tape - Google Patents

Abstract

In order to provide a thermal release adhesive tape which is well suited to use in thermal processing at high temperatures, exhibits adhesiveness of the adhesive layer that is markedly reduced by heating at an even a higher temperature after use in the thermal processing, allowing easy release from the adherend without leaving residue, and which exhibits excellent conformance to the surface texture of the adherend, a thermal release adhesive tape of the invention comprises a thermal release adhesive layer on at least one surface side of a backing material, wherein (a) the tensile strength of the backing material at 100% elongation is 0.9 MPa or less, (b) the compressive stress of the backing material at 50% compression is 2.0 MPa or less, and (c) the value of tan δ at the maximum temperature when using the adhesive tape at a temperature of 100°C or higher, obtained by dynamic viscoelastic measurement performed at a frequency of 10 Hz, is 0.80 or less. The thermal release adhesive layer 2 contains heat expanding microspheres, for which the foaming start temperature is at least 15°C higher than the maximum temperature during use, in an amount of at least 6 parts by mass but not more than 50 parts by mass per 100 parts by mass of the adhesive component that forms the thermal release adhesive layer.

Description

Heat-peelable adhesive tape

The present invention relates to heat-peelable adhesive tapes.

In various manufacturing steps including the manufacturing steps of electronic parts and semiconductor parts, it is known to use heat-peelable adhesive tapes that can be peeled off by reducing the adhesive force by heating, as the adhesive layer constituting the adhesive tape contains heat-expandable microspheres. Type adhesive tape technology. In recent years, there have been increasing types of solder bumps and metal pins provided on electrode portions of semiconductor elements for connection to substrate wiring portions. In order to improve the followability to the surface of a semiconductor element having solder bumps and metal pins, Patent Document 1 proposes the use of a porous base material as the base material. It is said that Patent Document 1 is a heat-peelable double-sided adhesive sheet in which a heat-peelable adhesive layer A is provided on one side of a porous substrate, and an adhesive layer B is provided on the other side. 0.9g/cm ³ or less and tensile modulus of elasticity 20MPa or less, it is possible to process workpieces with a surface with a maximum unevenness difference of 10μm or more.

Also, Patent Document 2 discloses a thermally peelable adhesive sheet in which a thermally expandable adhesive layer containing thermally expandable microspheres is laminated on at least one side of a base material via a rubber-like organic elastic layer. It is said that the heat-peelable adhesive sheet has excellent followability to uneven surfaces by setting the rubber-like organic elastic layer and the heat-expandable adhesive layer to specific thicknesses and thickness ratios. It is said that due to such followability, sufficient adhesive force can be exhibited even if the adherend surface is rough, even when using an adhesive sheet for dicing as a semiconductor substrate with a rough surface such as sealing resin. , It is also difficult for the chip to fly out, and after the processing is completed, there will be no stress on the adherend due to heating, and it can be easily peeled off. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2008-115272 [Patent Document 2] Japanese Unexamined Patent Publication No. 2014-037539

[Problem to be Solved by the Invention]

Patent Documents 1 and 2 disclose that a temperature of 100 to 250° C. is used as heat treatment conditions for peeling after processing. However, in the recent semiconductor manufacturing process, heat treatment is often performed in the state where the adhesive sheet is bonded, and a heat-peelable adhesive tape that can be easily peeled off by further heating without peeling even at a temperature of 100°C or higher is required. .

The present invention is accomplished in view of the above-mentioned problems, and provides an adhesive tape used in a heating step of electronic parts and semiconductor parts, which can be ideally used in a heating step at a high temperature, and if used in a heating step When heated at high temperature, the adhesiveness of the adhesive layer is significantly reduced, and there is no residual adhesive on the adherend, which can be easily peeled off. It is a heat-peelable adhesive tape with excellent followability to the unevenness of the adherend. [Means used to solve problems]

The inventors of this case have devoted themselves to research in order to achieve the above-mentioned purpose, and found that in order to solve the above-mentioned problems, a heat-peelable adhesive tape system is very effective, and finally completed the present invention. At least one side is equipped with a heat-peelable adhesive layer, which is characterized by: Of the aforementioned substrates (a) The tensile strength at 100% elongation is 0.9 MPa or less, (b) The compressive stress at 50% compression is 2.0MPa or less, (c) The value of tanδ at the maximum temperature when the heat-peelable adhesive tape is used at 100°C or higher obtained by dynamic viscoelasticity measurement at a frequency of 10 Hz is 0.80 or less, The aforementioned heat-peelable adhesive layer (d) Including heat-expandable pellets whose foaming start temperature is above the maximum temperature in use + 15°C or higher, the content of the above-mentioned heat-expandable pellets is relative to 100 parts by mass of the adhesive component forming the above-mentioned heat-peelable adhesive layer. The range of 6 mass parts or more and 50 mass parts or less. [Effect of Invention]

The heat-peelable adhesive tape of the present invention can be ideally used without peeling even in high-temperature steps in various manufacturing steps including manufacturing steps of electronic parts and semiconductor parts, and can be used by further heating after being used in the same step The adhesiveness is significantly reduced due to high temperature, and it can be easily peeled off without adhesive residue. It has excellent followability to the unevenness of the adherend.

Patent Documents 1 and 2 disclose examples in which the peeling temperature of the adhesive sheet is 100 to 120°C, but the use temperature in this case is of course lower than 100°C, and it is considered to be room temperature (around 25°C) since it is not specifically described. Therefore, use at a high temperature of 100° C. or higher, and further, peeling at a high temperature have not been sufficiently disclosed. It is better to use a soft base material to follow the unevenness of the adherend. However, if the heat resistance is not sufficient, there may be adhesive residue during thermal peeling, and the base material will become too soft and the peeling itself will become difficult. situation. Therefore, the present invention found that by using a base material having both flexibility and heat resistance, it can be easily peeled off by heating at a temperature higher than the use temperature without peeling off when used at a high temperature of 100° C. or higher. The object of the present invention can be attained by using in combination a heat-peelable adhesive layer containing heat-expandable beads that start to foam at a temperature higher than the use temperature in a predetermined amount.

The heat-peelable adhesive tape of the present invention will be described in detail below. The layer constitution of the heat-peelable adhesive tape of the present invention will be described using the schematic cross-sectional view shown in FIG. 1 .

Fig. 1(A) shows the laminated structure of the base material 1 and the heat-peelable adhesive layer 2 with the minimum layer structure, and Fig. 1(B) shows the reverse of the surface on which the heat-peelable adhesive layer 2 is further formed on the base material 1. The composition of the surface lamination support layer 3 . FIG. 1(C) shows an example in which an intermediate support layer 4 is provided on the surface of the base material 1 on which the heat-peelable adhesive layer 2 is formed. This is an example in which an intermediate support layer 4 is added to the layer configuration of FIG. 1(B), but It is also possible to add an additional intermediate support layer 4 to the layer shown in FIG. 1(A). FIG. 1(D) shows the layer composition of a double-sided adhesive tape with adhesive layers provided on both sides of a base material 1. It shows a layer composition in which a heat-peelable adhesive layer 2 is provided on one side and a second adhesive layer 5 is provided on the other side. The second adhesive layer 5 may be a normal adhesive layer or a heat-peelable adhesive layer. When the second adhesive layer 5 is used as a heat-peelable adhesive layer, the heating temperature for peeling may be the same as that of the heat-peelable adhesive layer 2 or may be different.

In order to prevent adjacent layers from sticking to each other when winding into a tape, a release film (not shown) can be provided on the adhesive surface of the heat-peelable adhesive layer and the surface of the substrate without a support layer. As the release film, one or both surfaces of a resin film such as a polyester (for example, polyethylene terephthalate: PET) film that has been subjected to a release treatment can be used.

Each layer of the heat-peelable adhesive tape of the present invention will be described below. ＜Substrate＞ The substrate of the heat-peelable adhesive tape of the present invention satisfies the following conditions (a) to (c) at the same time. (a) The tensile strength at 100% elongation is 0.9 MPa or less, (b) The compressive stress at 50% compression is 2.0MPa or less, (c) The value of tanδ at the maximum temperature when the heat-peelable adhesive tape is used at 100° C. or higher obtained by dynamic viscoelasticity measurement at a frequency of 10 Hz is 0.80 or less.

The tensile strength of (a) is to stretch the test piece (thickness 800μm, width 25mm, length 100mm) at 23°C, 50%RH, at a speed of 30mm and 300mm/min between the grippers, and measure the elongation The tensile strength at the time point where the ratio is 100%. For the measurement, a commercially available tensile testing machine can be used. The tensile strength is below 0.9MPa, preferably below 0.8MPa.

The compressive stress in (b) is to compress the test piece (30mm×30mm×12mm) at 23°C and 50%RH at a speed of 10mm/min, and measure the compressive stress at 50% deformation. For the measurement, a commercially available compression tester can be used. The compressive stress is less than 2.0MPa, preferably less than 1.5MPa.

The tanδ (loss tangent) of (c) is for the test piece (10mm×10mm×2mm) using a dynamic viscoelasticity measuring device, while applying a shear strain at a frequency of 10Hz, at a heating rate of 10℃/min, at -50℃ The storage elastic coefficient (G') and the loss elastic coefficient (G") are measured in the range of ~250°C. It is obtained from G"/G' at the maximum temperature of the heat-peelable adhesive tape when it is used above 100°C Derived from tanδ. Here, "the maximum temperature at the time of use of the heat-peelable adhesive tape of 100° C. or higher" refers to the maximum temperature of 100° C. or higher when the heat-peelable adhesive tape is actually used, and the maximum temperature is set as the specific heat-peelable adhesive tape. The temperature at which the foaming initiation temperature of the heat-expandable pellets contained in the layer is lower by 15°C or more. Therefore, it means that even if the same base material is used, the measurement temperature of tan δ changes depending on the combined heat-peelable adhesive layer. The value of tan δ is not more than 0.80, preferably not more than 0.70.

As the material of the substrate, any material can be used as long as it satisfies the above conditions (a) to (c), but as the base resin (main component), acrylic resin, silicone resin, urethane resin Either is preferred. From these resins, one can be selected that satisfies the tensile strength and compressive stress specified in the above-mentioned conditions (a) and (b), and has sufficient heat resistance required for the value of tanδ in the above-mentioned condition (c) to be 0.80 or less. Material.

An acrylic resin composition containing an acrylic copolymer resin as an acrylic resin mainly contains an alkyl (meth)acrylate as a monomer component and a vinyl monomer copolymerizable therewith can be prepared.

Examples of the alkyl (meth)acrylate include those having 1 to 20 carbon atoms in the alkyl ester moiety, preferably 1 to 12 carbon atoms, and more preferably 1 to 8 carbon atoms. Specific examples of alkyl (meth)acrylates include: methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, (meth)acrylate base) isobutyl acrylate, tertiary butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl (meth)acrylate, isohexyl (meth)acrylate, octyl (meth)acrylate, Isooctyl (meth)acrylate, Ethylhexyl (meth)acrylate, Nonyl (meth)acrylate, Isononyl (meth)acrylate, Decyl (meth)acrylate, Iso(meth)acrylate Decyl ester, lauryl (meth)acrylate, isododecyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, etc. One of these may be used, or two or more of them may be used in combination. The amount of alkyl (meth)acrylate-based total monomers is at least 50% by mass, preferably at least 60% by mass, more preferably at least 70% by mass, and most preferably at least 80% by mass.

Examples of copolymerizable vinyl monomers include (meth)acrylic acid, β-carboxyethyl (meth)acrylate, and carboxylic acids containing itaconic acid, crotonic acid, maleic acid, and fumaric acid. (Meth)acrylic monomer, (meth)acrylate-2-hydroxyethyl, (meth)acrylate-2-hydroxypropyl, (meth)acrylate-2-hydroxybutyl, (meth)acrylate- 4-hydroxybutyl ester, 2-hydroxyhexyl (meth)acrylate, monoester of (meth)acrylic acid and polyethylene glycol or polypropylene glycol and other hydroxyl-containing copolymerizable monomers, (meth)acrylic acid N-alkyl substituted (meth)acrylamide such as amine, N-isopropyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl (Meth)acrylamide, etc. esters, nitrogen-containing acrylic monomers such as dimethylaminoethyl (meth)acrylate and dimethylaminopropyl (meth)acrylate, vinyl monomers such as vinyl acetate, etc. One of these may be used, or two or more of them may be used in combination. Among them, acrylic acid is preferably contained, and acrylic acid is preferably contained in an amount of 1 to 20% by mass in all monomers, and more preferably contained in an amount of 4.75 to 19% by mass.

For the acrylic resin composition, for example, alkyl (meth)acrylate and acrylic acid are polymerized to prepare acrylic syrup, and then other monomers and additives of the acrylic resin syrup are added to obtain the acrylic resin composition. The acrylic resin composition can be coated on a mold-releasable support, and cured by UV curing or the like to produce a substrate.

As additives added to the resin composition, hollow particles such as resin hollow balls and glass hollow balls, resin particles such as urethane beads, epoxy-based, isocyanate-based, multifunctional acrylate-based crosslinking agents, Known additives such as fillers, colorants, antioxidants, ultraviolet absorbers, surfactants, polymerization initiators, and chain transfer agents.

As for the silicone resin and the urethane resin, those that satisfy the above-mentioned conditions (a) to (c) may be selected by combining raw materials and material combinations that can be used as a base material for adhesive tapes. In the case of polysiloxane resin, it is preferable to use a platinum-based catalyst that promotes the dehydration condensation of silane compounds. The urethane-based resin is preferably used in combination with an epoxy-based, isocyanate-based, or other cross-linking agent. Moreover, the base material which satisfies the said conditions (a)-(c) can also be selected from among commercially available ones as a base material for adhesive tapes. In this case, it is also possible to use a urethane foam material or the like as a product made of a porous body.

The thickness of the substrate is not particularly limited as long as it meets the purpose of use and satisfies the followability to unevenness, but it is preferably 30 μm or more, and more preferably 50 μm or more. In addition, the upper limit of the thickness is preferably not more than 2000 μm, more preferably not more than 1000 μm.

＜Heat Peelable Adhesive Layer＞ The heat-peelable adhesive layer of the present invention includes an adhesive and heat-expandable pellets, and the content of the heat-expandable pellets is in the range of 6 parts by mass to 50 parts by mass relative to 100 parts by mass of the adhesive component forming the heat-peelable adhesive layer . The foaming initiation temperature of the heat-expandable pellets is a temperature above the maximum temperature at the time of use specified in the above-mentioned condition (c) + 15°C.

The heat-expandable pellets used in the present invention include, for example, microspheres in which substances such as isobutane, propane, and pentane that are easily vaporized and expanded by heating are contained in an elastic shell (shell). The outer casing is mostly formed of hot-melt substances and substances destroyed by thermal expansion. Examples of the material forming the shell include: vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, polyvinyl chloride, etc. . The thermally expandable pellets can be produced by conventional methods, such as coacervation, interfacial polymerization, and the like. The foaming start temperature can be mainly controlled by the thickness of the shell, and the thicker the thickness, the higher the foaming start temperature tends to be. For example, Matsumoto Microsphere (registered trademark) F and FN series with a shell film thickness of 2-15 μm and an average particle diameter of 5-50 μm are commercially available from Matsumoto Yushi Pharmaceutical Co., Ltd. and can be ideally used. The heat-expandable pellets may be selected on the basis of the foaming start temperature and the expansion ratio as rough references.

As the adhesive component for forming the heat-peelable adhesive layer, any adhesive component may be used as long as it has sufficient adhesive force at the use temperature and can be peeled off by the foaming of the heat-expandable pellets by further heating at a high temperature. use. Specifically, a (meth)acrylic-type copolymer, a silicone-type adhesive, a polyester-type adhesive, etc. are mentioned. In particular, it is also preferable to select the same kind of resin as the resin constituting the base material from the viewpoint of adhesiveness with the base material.

As a (meth)acrylic-type copolymer, the vinyl-type monomer used for a base material can be used in combination. Among these, it is preferable to contain at least one structural unit derived from an alkyl (meth)acrylate as a main component and to contain a structural unit derived from acrylic acid. Moreover, it is preferable to contain the structural unit derived from acrylic acid at 2 mass % or more with respect to 100 mass % of total monomer units, and it is more preferable to contain 5 mass % or more. As long as the structural unit derived from acrylic acid is 2% by mass or more based on 100% by mass of the total monomer units, even if the use temperature is as high as 150° C., the height difference followability after heating is excellent. Moreover, from the viewpoint of improving the adhesive force, it is also a preferable aspect to mix and use a hydroxyl group-containing acrylate.

The content of the heat-expandable pellets is in the range of 6 to 50 parts by mass, preferably 6 to 40 parts by mass, relative to 100 parts by mass of the adhesive component forming the heat-peelable adhesive layer. If the content of the heat-expandable pellets is less than 6 parts by mass, the heat-peelability due to the foaming of the heat-expandable pellets cannot be fully exhibited. Also, if the content of the heat-expandable pellets exceeds 50 parts by mass, the relative amount of the adhesive component decreases, making it impossible to obtain the desired adhesive force.

Also, if the foaming start temperature of the heat-expandable pellets is less than 15°C relative to the maximum temperature during use specified in the aforementioned condition (c), peeling during heating and use, and thermal peelability will decrease. After the thermal peeling temperature, when returning to normal temperature and peeling, the adhesive force is not sufficiently reduced, and the peeling becomes difficult.

In addition to the above-mentioned adhesive components and heat-expandable pellets, the heat-peelable adhesive layer may contain known additives within the range that does not impair the effect of the present invention. Examples of additives include ultraviolet absorbers, antioxidants, colorants, various fillers, and the like.

The thickness of the heat-peelable adhesive layer may be greater than the particle size of the added heat-expandable pellets and within a range that does not impair the followability of unevenness by the base material. For example, it may be selected from the thickness of the base material and the particle diameter of the heat-expandable pellets within the range of 10 to 100 μm. In addition, in the case of commercially available products, the particle size of thermally expandable pellets can be set by predicting the maximum particle size from the average particle size (catalogue value), and large particles can also be removed by sieving, and the sieve of the sieve The mesh is set to the set particle size.

＜Support layer＞ The heat-peelable adhesive tape of the present invention may be provided with a resin film different from the base material 1 on at least one side of the base material 1 as the support layer 3 or the intermediate support layer 4 as shown in FIG. 1(B) and (C). The base material used in the present invention may have tackiness, and when the thickness of the base material is thin, sufficient strength may not be obtained. Therefore, it is better to pre-arrange the resin film as the support layer 3 or the intermediate support layer 4 .

The resin contained in the resin film is preferably lower in adhesiveness than the substrate, has heat resistance, and has excellent strength, and is selected from polyimide resin, fluororesin, polyester resin, and polyetheretherketone resin. At least one selected from the group consisting of polyphenylene sulfide resin and polycycloolefin resin is preferred. Among them, polyimide resin and polyethylene terephthalate (PET) are preferred.

The thickness of the support layer 3 is preferably 20 μm or more, more preferably 40 μm or more, from the viewpoint of imparting strength appropriately. As an upper limit, what is necessary is just to set considering the thickness of a base material, and the thickness of the whole heat-peelable adhesive tape. The thickness of the intermediate support layer 4 is preferably not more than 20 μm, more preferably not more than 15 μm, from the point of view that the higher the thickness, the less likely it is to follow the level difference caused by the base material. The lower limit is not particularly limited, but in terms of providing the intermediate support layer 4, it is preferably 1 μm or more, and more preferably 5 μm or more.

＜Double-sided adhesive tape＞ The heat-peelable adhesive tape of the present invention can be made as a double-sided adhesive tape in which a second adhesive layer 5 is provided on the substrate surface opposite to the surface on which the heat-peelable adhesive layer 2 is formed, as shown in FIG. 1(D). At this time, the heat-peelable adhesive layer 2 may be referred to as a first adhesive layer with respect to the second adhesive layer 5 . The first adhesive layer is the heat-peelable adhesive layer of the present invention, but the second adhesive layer may be a heat-peelable adhesive layer or a normal adhesive layer. When the second adhesive layer is a heat-peelable adhesive layer, it may be the same as or different from the heat-peelable adhesive layer of the first adhesive layer. That is, a heat-peelable adhesive layer that can be thermally peeled at a temperature higher or lower than that of the first adhesive layer can also be used. In this way, the temperatures for tearing off the members attached to the respective surfaces of the double-sided adhesive tape can be set separately.

＜How to use heat-peelable adhesive tape＞ The heat-peelable adhesive tape of the present invention is used in a manufacturing step of a member having unevenness on the surface. Examples of members having irregularities on the surface include semiconductor substrates, electronic components, and the like. In particular, the adherend to be targeted in the present invention is a member used for manufacture requiring a temperature of 100° C. or higher. For example, a temperature of about 150 to 200°C may be added in steps such as reflow. In the present invention, the highest attained temperature in such a manufacturing step is defined as the maximum temperature (use temperature) at the time of use of the heat-peelable adhesive tape. The heat-expandable pellets contained in the heat-peelable adhesive layer have a foaming start temperature in a temperature range higher than 15°C higher than the use temperature, so the adhesive force can be maintained without foaming at the use temperature. In the case of subsequent peeling, by heating to a temperature higher than the foaming start temperature, the heat-expandable beads expand and foam, thereby producing the effect of separating the heat-peelable adhesive layer from the adherend. The heating temperature at this time is referred to as the thermal peeling temperature, and it is sufficient as long as it is higher than the foaming start temperature as described above, but the higher the thermal peeling temperature is than the foaming start temperature, the faster the time until foaming is completed becomes. Therefore, the thermal peeling temperature is preferably a temperature higher than the foaming start temperature by 30° C. or higher, more preferably 40° C. or higher. Also, the time for thermal peeling depends on the temperature difference between the thermal peeling temperature and the foaming start temperature, and the shell material and thickness of the heat-expandable pellets, and the type of vapor contained inside, and can be appropriately set. In addition, in order to avoid residues of heat-expandable pellets and adhesive residue remaining on the adherend (residual adhesive) during peeling, it is preferable to peel off after cooling. The temperature during peeling is lower than the use temperature, preferably below 100°C, more preferably below 50°C, and may be cooled to room temperature (around 25°C) for peeling. [Example]

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. Moreover, "part" or "%" in an Example and a comparative example shows the value of a mass standard unless otherwise specified.

[Substrate preparation method] ・Acrylic resin slurry preparation method Put the composition shown in Table 1 into a flask equipped with a stirrer, a reflux cooler, a thermometer, and a nitrogen gas inlet, and use an ultraviolet irradiation device (manufactured by Panasonic Corporation: trade name "Aicure UP50") was irradiated with ultraviolet rays having an irradiation intensity of 800 to 1,200 mW/cm ² (measured using a light meter UVM-100 manufactured by Aitec System Co., Ltd.) for 8 to 12 minutes to photopolymerize, thereby obtaining an acrylic resin syrup.

[Table 1] Table 1 resin paste 1 Resin paste 2 resin paste 3 Resin paste 4 2-Ethylhexyl acrylate [parts] 90 95 82 80 Acrylic [parts] 10 5 18 20 n-dodecyl mercaptan [parts] 0.01 0.01 0.01 0.01 α-Hydroxyacetophenone [parts] 0.01 0.01 0.01 0.01 α-Hydroxyacetophenone: IGM Resins, product name "Omnirad 1173"

・Preparation of acrylic base material Add materials to each of the obtained resin pastes 1 to 4 in the composition shown in Table 2, and mix uniformly to obtain a base material composition. The substrate composition is coated on the release-treated surface of a 50 μm-thick PET release film (manufactured by Fujimori Industrial Co., Ltd., trade name "FILMBYNA (registered trademark) KF#50") that has been treated with silicone release on one side. The release-treated surface of the release-treated PET release film is placed on the substrate composition, and is sandwiched by two PET release films. A fluorescent lamp (manufactured by Toshiba Corporation: FL20S W) with an irradiation intensity of 3.0 to 5.0 mW/cm ² was irradiated from both sides for 30 seconds to 2 minutes depending on the coating thickness to harden the substrate composition to obtain an acrylic substrate. The thickness of the acrylic substrate was adjusted so as to be 50 μm to 800 μm.

[Table 2] Table 2 material type material name Acrylic substrate No. [parts] AS1 AS2 AS3 AS4 AS5 AS6 AS7 AS8 AS9 AS10 acrylic resin paste resin paste 1 95 95 95 95 Resin paste 2 95 95 100 resin paste 3 95 95 Resin paste 4 95 monomer acryloyl phenoline 5 5 5 5 5 5 5 5 5 spherical particles Resin hollow ball 1 1 1 0.3 1 1 1 Glass hollow ball 2 Urethane beads 10 crosslinking agent 1,6-Hexanediol diacrylate 0.1 0.1 0.1 0.1 0.01 0.1 0.1 0.1 0.1 0.01 Initiator α-Hydroxyacetophenone 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5

The details of the materials in Table 2 are as follows: ・Resin hollow ball: Matsumoto Yushi Pharmaceutical Co., Ltd., trade name "F-80DE" ・Glass hollow ball: Made by Potters-Ballotini, trade name "34P30T" ・Urethane beads: Manufactured by Negami Kogyo Co., Ltd., brand name "Art Pearl P-800T" ・α-Hydroxyacetophenone: IGM Resins, trade name "Omnirad1173"

[Evaluation of physical properties of base material] For the obtained base material, the tensile strength, compressive stress, and tan δ were measured by the following methods. ・Tensile strength of substrate A substrate with a thickness of 800 μm, a width of 25 mm, and a length of 100 mm was tested at 23°C, 50% RH, with a distance between grippers of 30 mm and a test speed of 300 mm/min using a tensile testing machine (manufactured by Toyo Seiki Seisakusho: Strograph V-1C). Stretch under these conditions, and measure the tensile strength at 100% elongation.

・Compressive stress of base material Base materials of 30 mm square were laminated to form a laminate with a thickness of 12 mm. This laminate was compressed using a compression tester (manufactured by Shimadzu Corporation: AG-50kNX Plus) at 23° C., 50% RH, and a test speed of 10 mm/min, and the compressive stress at 50% deformation was measured.

・Substrate tanδ 10 mm square substrates were laminated to form a laminate with a thickness of 2 mm. Using a dynamic viscoelasticity measuring device (manufactured by TA Instruments: ARES-G2), this laminate was subjected to a temperature increase rate of 10°C/min while applying a shear strain at a frequency of 10 Hz in the range of -50°C to 250°C. The storage coefficient of elasticity (G') and the loss coefficient of elasticity (G") were measured. From the storage coefficient of elasticity (G') and the loss coefficient of elasticity (G"), the loss tangent tanδ at each temperature was calculated by the following formula. tanδ=loss coefficient of elasticity (G")/storage coefficient of elasticity (G') Table 3 shows the above results. Moreover, it evaluated similarly about the polysiloxane base material and urethane base material which are commercially available.

[table 3] table 3 Substrate properties Substrate name AS1 AS2 AS3 AS4 AS5 AS6 AS7 AS8 Si PU AS9 AS10 Tensile strength (MPa) 0.14 0.07 0.85 0.72 0.06 0.06 0.08 0.08 0.54 0.18 1.05 0.05 Compressive strength (MPa) 0.28 0.22 0.91 1.87 0.17 0.30 0.38 0.38 1.48 0.06 2.54 0.11 tanδ 100°C 0.48 0.52 0.48 0.60 0.66 0.53 0.53 0.53 0.06 0.27 0.56 0.84 150°C 0.41 0.55 0.36 0.43 0.75 0.51 0.49 0.57 0.05 0.24 0.40 0.90 180°C 0.36 0.34 0.30 0.43 0.71 0.52 0.47 0.60 0.04 0.33 0.34 0.91

The substrate names in Table 3 are as follows. Si: Polysiloxane material, trade name "Unicon UT-30", manufactured by Kotec Corporation PU: Urethane base material, brand name "PureCell (registered trademark) UC150PR", manufactured by INOAC Corporation In the above, the colored portion means a portion that does not satisfy the conditions of the present invention, and it is the same in the following tables. Substrate AS9 is a substrate that does not satisfy the conditions (a) and (b) of the present invention, and substrate AS10 is a substrate that does not satisfy the condition (c) of the present invention. Regarding the rest of the AS1~AS8, Si, PU substrates, they are substrates that can be used at any operating temperature of 100~180°C.

[How to make heat-peelable adhesive layer] ・Preparation method of base polymer (acrylic copolymer) Acrylic copolymers Ac1 to Ac4 having the compositions shown in Table 4 were polymerized. The blending ratio of each component in Table 4 shows the ratio when the total is made into 100 parts. For reference, the theoretical Tg and weight average molecular weight (Mw) of each acrylic copolymer are collectively described in Table 4. Theoretical Tg is a value calculated by the formula of FOX, and can be adjusted by properly selecting the composition of acrylic monomers. Moreover, this weight average molecular weight (Mw) is the value measured by the GPC method, and the weight average molecular weight of the standard polystyrene conversion of an acrylic-type copolymer was measured on the following measurement apparatus and conditions. ・Device: LC-2000 series (manufactured by JASCO Corporation) ・Column: Shodex KF-806M×2, Shodex KF-802×1 ・Washing solution: Tetrahydrofuran (THF) ・Flow rate: 10mL/min ・Column temperature: 40°C ・Injection volume: 100μL ・Detector: Refractive index meter (RI) ・Measurement sample: Dissolve acrylic polymer in THF to prepare acrylic polymer solution with a concentration of 0.5%, and remove impurities by filtering with a filter.

The weight average molecular weight (Mw) can be determined by appropriately selecting the type and amount of the polymerization initiator (for example, 0.1 part of dodecyl peroxide relative to 100 parts of acrylic monomer), chain The type and amount of the transfer agent (for example, 0.1 part of n-dodecanethiol relative to 100 parts of acrylic acid monomers), the polymerization initiation concentration (for example, 50%), etc. are adjusted.

[Table 4] Table 4 Acrylic Copolymer Ac1 Ac2 Ac3 Ac4 Composition/part 2-Ethylhexyl Acrylate 70.0 2-Ethylhexyl Acrylate 86.0 2-Ethylhexyl Acrylate 39.5 2-Ethylhexyl Acrylate 90.0 Butyl acrylate 5.0 Methyl acrylate 3.0 Methyl acrylate 10.0 acryloyl phenoline 1.9 Methyl acrylate 10.0 acrylic acid 7.0 acrylic acid 20.0 acrylic acid 3.0 acrylic acid 10.0 2-Hydroxyethyl Acrylate 2.0 2-Hydroxypropyl Acrylate 0.5 4-Hydroxybutyl Acrylate 0.1 2-Hydroxyethyl Acrylate 5.0 vinyl acetate 2.0 2-methoxyethyl acrylate 30.0 vinyl acetate 5.0 Theoretical Tg (°C) -63 -73 -43 -76 mw 1.01 million 350,000 250000 750,000

[Preparation method of adhesive composition] With respect to 100 parts of solid content of each adhesive, materials were added and mixed uniformly in the composition shown in the following Table 5, and the heat-peelable adhesive composition was obtained.

[table 5] table 5 adhesive composition Adhesive No./[part] type material name AD1 AD2 AD3 AD4 AD5 AD6 AD7 AD8 AD9 AD10 AD11 AD12 ADSi ADPE Adhesive (solid content) Ac1 100 100 100 100 100 100 100 100 Ac2 100 100 Ac3 100 Ac4 100 silicone adhesive 100 polyester adhesive 100 Thermally expandable pellets FN-190SSD 20 40 20 20 20 20 20 20 F-260D 20 FN-100MD 20 10 8 5 F-50D 20 crosslinking agent E-5CM 10 10 10 10 10 12 10 10 20 20 10 10 L-45E 10 catalyst CAT-PL-50T 2 Antioxidants Irganox 1010 1 1 1 1 1 1 1 1 1 1 1 1 1

In Table 5, the materials used are as follows: ・Silicone adhesive: Shin-Etsu Chemical Co., Ltd., product name "KR-3700" and "X-40-3306" mixture (mass ratio 80/20) ・Polyester adhesive: manufactured by Mitsubishi Chemical Corporation, brand name "NP-110S50" ・FN-190SSD: Brand name "Matsumoto Microsphere (registered trademark) FN-190SSD", manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., foaming start temperature 171°C ・F-260D: Brand name "Matsumoto Microsphere (registered trademark) F-260D", manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., foaming start temperature 198°C ・FN-100MD: Brand name "Matsumoto Microsphere (registered trademark) FN-100MD", manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., foaming start temperature 119°C ・F-50D: Brand name "Matsumoto Microsphere (registered trademark) F-50D", manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., foaming start temperature 112°C ・E-5CM: Brand name, manufactured by Soken Chemical Co., Ltd., epoxy-based crosslinking agent, solid content 5% ・L-45E: Trade name, manufactured by Tosoh Corporation, isocyanate-based crosslinking agent, solid content 45% ・CAT-PL-50T: Brand name, manufactured by Shin-Etsu Chemical Co., Ltd., platinum catalyst ・Irganox 1010: Brand name, manufactured by BASF Corporation, hindered phenolic antioxidant

Examples 1-22, Comparative Examples 1-4 [How to make adhesive tape] The adhesive composition obtained above was placed on a 50 μm thick PET release film (manufactured by Fujimori Industrial Co., Ltd., trade name "FILMBYNA (registered trademark) KF#50") that had been treated with polysiloxane, with the thickness of the adhesive layer Apply so that it becomes 50 micrometers. Next, the crosslinking reaction was performed while drying the diluted solvent at 50 to 110° C. by putting it into a dryer (manufactured by ESPEC: PHH-201) to form a heat-expandable adhesive layer. Peel off the PET release film on both sides of the substrate, transfer a heat-expandable adhesive layer to one side of the substrate, and attach a 50 μm thick PET film (manufactured by Toray Corporation, trade name "Lumirror #50-S10") to the other side. ”), and maintained at 40° C. for 3 days to obtain an adhesive tape. A heat-peelable adhesive tape having a layer composition shown in FIG. 1(B) was prepared using the combinations of the base material and the adhesive shown in Table 6. In addition, the physical properties of the substrate measured by the following method and the foaming start temperature of the thermally expandable pellets, the test temperature based on it (the use temperature of the adhesive tape), the thermal peeling temperature, and the relationship between the tanδ of the substrate at the test temperature The values are shown in Table 6 together.

[Physical property evaluation of adhesive layer] ・Measurement method of foaming initiation temperature of heat-expandable pellets The foaming initiation temperature of the heat-expandable pellets can be obtained by using a thermal analyzer TMA (manufactured by Hitachi Advanced Technology Co., Ltd.: TMA7100). The foaming start temperature of the heat-expandable ball is set to put the heat-expandable ball into a 5mmφ aluminum pot and cover the inner cover. When analyzing in the compression mode (L structure control, heating rate: 10°C/min), the terminal is measured. The temperature at which the displacement in the vertical direction begins to rise.

[Table 6] Table 6-1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Substrate Substrate name AS1 AS2 AS2 AS2 AS3 AS4 AS5 AS6 AS7 Substrate thickness (μm) 200 200 50 800 200 200 200 200 200 Adhesive Adhesive name AD1 AD1 AD1 AD1 AD1 AD1 AD1 AD1 AD1 Foaming start temperature (°C) 171 171 171 171 171 171 171 171 171 Parts of blowing agent 20 20 20 20 20 20 20 20 20 Test conditions Test temperature (℃) 150 150 150 150 150 150 150 150 150 Thermal peeling temperature (°C) 220 220 220 220 220 220 220 220 220 at test temperature 0.41 0.55 0.55 0.55 0.36 0.43 0.75 0.51 0.49 Substrate tanδ Table 6-2 Example 10 Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 Substrate Substrate name AS8 Si PU AS1 AS1 AS1 AS1 AS1 AS1 Substrate thickness (μm) 200 250 550 200 200 200 200 200 200 Adhesive Adhesive name AD1 ADSi AD1 AD2 AD3 AD5 AD6 AD8 AD9 Foaming start temperature (°C) 171 171 171 198 119 119 119 171 171 Parts of blowing agent 20 20 20 20 10 10 8 40 20 Test conditions Test temperature (℃) 150 150 150 180 100 100 100 150 150 Thermal peeling temperature (°C) 220 220 220 260 180 180 180 220 220 at test temperature 0.57 0.05 0.24 0.36 0.48 0.48 0.48 0.41 0.41 Substrate tanδ Table 6-3 Example 19 Example 20 Example 21 Example 22 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Substrate Substrate name AS1 AS1 AS1 AS1 AS9 AS10 AS1 AS1 Substrate thickness (μm) 200 200 200 200 200 200 200 200 Adhesive Adhesive name AD10 AD11 ADPE AD12 AD1 AD1 AD4 AD7 Foaming start temperature (°C) 171 171 171 171 171 171 112 119 Parts of blowing agent 20 20 20 20 20 20 20 5 Test conditions Test temperature (℃) 150 150 150 150 150 150 100 100 Thermal peeling temperature (°C) 220 220 220 220 220 220 140 180 at test temperature 0.41 0.41 0.41 0.41 0.40 0.90 0.48 0.48 Substrate tanδ

In the above-mentioned Table 6, the step followability was evaluated for the example where the test temperature was 150°C. ・Level followability A polyimide tape (manufactured by Teraoka Seisakusho Co., Ltd., product name "No. 6544") with a thickness of 90 μm and a size of 5 mm×30 mm was attached to a glass plate to produce a glass with a pseudo-level difference for testing. Place the heat-peelable adhesive layer side of the 20mm square adhesive tape on the glass with height difference, and use a 5kg rubber roller to go back and forth once at 300mm/min to make an adhesion test piece. Using a microscope (manufactured by Keyence: VHX-6000), the widths of bubbles generated around the height difference were measured at 5 mm intervals, and the average value was calculated. After putting the test piece into a dryer and heating at a test temperature of 150° C. for 30 minutes, the cell width was similarly calculated. The height difference followability was evaluated by the following criteria. A: The bubble width is less than 1mm B: Bubble width of 1 mm or more but less than 5 mm C: Bubbles are connected or the adhesive tape is peeled off from the test piece.

[Table 7] Table 7 Substrate Adhesive height difference followability Substrate name Thickness (μm) Tensile strength (MPa) Compressive strength (MPa) Before heating after heating Example 1 AS1 200 0.14 0.28 AD1 A A 2 AS2 200 0.07 0.22 AD1 A A 3 AS2 50 0.07 0.22 AD1 A A 4 AS2 800 0.07 0.22 AD1 A A 5 AS3 200 0.85 0.91 AD1 A A 6 AS4 200 0.72 1.87 AD1 A A 7 AS5 200 0.06 0.17 AD1 A A 8 AS6 200 0.06 0.30 AD1 A A 9 AS7 200 0.08 0.38 AD1 A A 10 AS8 200 0.08 0.38 AD1 A A 11 Si 250 0.54 1.48 ADSi A A 12 PU 550 0.18 0.06 AD1 A A 17 AS1 200 0.14 0.28 AD8 A A 18 AS1 200 0.14 0.28 AD9 A A 19 AS1 200 0.14 0.28 AD10 A A 20 AS1 200 0.14 0.28 AD11 A A twenty one AS1 200 0.14 0.28 ADPE A A twenty two AS1 200 0.14 0.28 AD12 A B Comparative example 1 AS9 200 1.05 2.54 AD1 B C

In Comparative Example 1, since the base material used was an AS9 base material that did not satisfy the above-mentioned conditions (a) and (b) of the present invention, it was confirmed that the flexibility was low and the step followability was poor. As shown in Examples 2 to 4, it can be seen that the thickness of the base material has little influence.

heat resistance The influence of substrate tan δ under the above condition (c) was evaluated. Specifically, in the example of an acrylic substrate with a substrate thickness of 200 μm, the adhesive tape was cut into 20 mm squares, and the thickness (manufactured by Peacock: Dial Thickness Gauge G-6) and size (manufactured by Keyence: VHX) were measured. -6000). Place a 20mm square adhesive tape on an aluminum plate (A1050P) with a thickness of 1.0mm and 50mm×125mm, and place a float glass plate (R 3202) weighing 20g (thickness 2.8mm, 50mm×60mm) on the adhesive tape. Throw it into a dryer (ESPEC: PHH-201) and heat it at the test temperature listed in Table 5 for 30 minutes, then measure the thickness and size of the adhesive tape. The thickness is measured at the center of the tape, and the size is measured at 5 mm intervals in the width direction and length direction of the tape at 3 points each, and a total of 6 points is used to calculate the average value. The heat resistance was evaluated by the following criteria. A: The thickness reduction before and after heating does not reach 15%, or the size change does not reach 0.5mm C: The thickness reduction before and after heating is more than 15%, or the size change is more than 0.5mm The results are shown in Table 8.

[Table 8] Table 8 Example comparative example 1 2 5 6 7 8 9 11 12 13 1 2 Substrate AS1 AS2 AS3 AS4 AS5 AS6 AS7 Si PU AS1 AS9 AS10 Test temperature (℃) 150 150 150 150 150 150 150 150 150 180 150 150 tanδ (test temperature) 0.41 0.55 0.39 0.60 0.51 0.49 0.57 0.05 0.24 0.36 0.40 0.90 Heat Resistance Test Results A A A A A A A A A A A C

As can be seen from Table 8 above, when the tan δ at the processing temperature of the substrate is 0.80 or less, deformation during processing can be suppressed. In Comparative Example 2 in which tan δ exceeds 0.80, the dimensional change becomes large. In addition, in Example 11 using a polysiloxane base material and Example 12 using a urethane base material, the tan δ is also 0.80 or less, and deformation during processing can be suppressed.

Next, the adhesive force and thermal peelability were evaluated. ・Initial adhesion Attach an adhesive tape with a width of 10mm and a length of 100mm to an aluminum plate (A1050P) with a thickness of 1.0mm and a thickness of 50mm×125mm. After using a 5kg roller to go back and forth once at a speed of 300mm/min and crimping it, leave it at 23°C and 50%RH for 20 to 40 minutes. Use a tensile testing machine to measure the peeling force of the adhesive layer at 23°C, 50% RH, test speed 300mm/min, and peeling angle 90°, and set it as the initial adhesive force.

・Adhesion after heating Carry out lamination and crimping of the adhesive tape in the same manner as the measurement of the initial adhesive force, put it into a dryer and heat it at the test temperature listed in Table 9 for 30 minutes. Take it out from the dryer, and place it at 23°C, 50%RH for 20-40 minutes, then use a tensile tester to measure the peeling force of the tape at 23°C, 50%RH, test speed 300mm/min, and peeling angle 90° .

・Heat Peelability Heat at the same test temperature as the adhesive force after heating, take it out of the dryer and leave it at 23°C and 50%RH for 20 to 40 minutes, then put it into the dryer set at the thermal peeling temperature listed in Table 9 and heat for 5 minute. Take it out from the drier, and let it stand at 23° C. and 50% RH for 20 to 40 minutes. At this time, the person who peeled off naturally was set to "A". For those who did not peel off naturally, the peeling force was evaluated in the same manner as the above-mentioned adhesive force, and the peeling force was less than 1.0 N/10 mm as "B", and 1.0 N/10 mm or more as "C". The results are shown in Table 9.

[Table 9] Table 9 Example comparative example 1 11 13 14 15 16 17 18 19 20 twenty one twenty two 3 4 Substrate AS1 Si AS1 AS1 AS1 AS1 AS1 AS1 AS1 AS1 AS1 AS1 AS1 AS1 Substrate thickness (μm) 200 250 200 200 200 200 200 200 200 200 200 200 200 200 Adhesive AD1 ADSi AD2 AD3 AD5 AD6 AD8 AD9 AD10 AD11 ADPE AD12 AD4 AD7 Thermally expandable pellets Foaming start temperature (°C) 171 171 198 119 119 171 171 171 171 171 171 171 112 119 parts/adhesive 100 parts 20 20 20 20 10 8 40 20 20 20 20 20 20 5 initial adhesion [N/10mm] 9.22 1.30 2.39 2.04 2.34 3.79 1.93 6.51 1.83 8.26 0.89 2.10 2.55 1.66 Adhesion after heating Test temperature (℃) 150 150 180 100 100 100 150 150 150 150 150 150 100 100 [N/10mm] 23.62 0.77 10.65 4.62 5.16 4.88 13.08 16.31 6.21 14.16 0.97 1.88 4.13 3.10 Hot Peelability Thermal peeling temperature (°C) 220 220 260 180 180 220 220 220 220 220 220 220 140 180 Evaluation (peeling force [N/10mm]) A A A A A A A A A B A A C C (0.56) (1.90) (2.74)

Example 23 On the side of the substrate opposite to the side where the heat-peelable adhesive layer is formed, change the PET film as the support layer to a 50 μm thick PET release film (manufactured by Fujimori Industrial Co., Ltd., product name "FILMBYNA") that has been treated with silicone release. (registered trademark) KF#50"), and obtained the adhesive tape similarly to Example 1 except this. The layer configuration except for the PET release film is shown in Fig. 1(A). In addition, in the height difference followability test, the PET release film was peeled off and heated, and in the adhesion measurement, the PET release film was peeled off, and a 50 μm PET film (manufactured by Toray Corporation, product name "Lumirror#") was attached. 50-S10") and determined.

Example 24 An adhesive tape was obtained in the same manner as in Example 1 except that the PET film on the opposite side of the heat-peelable adhesive layer was changed to a 50 μm thick PI film (manufactured by Toray Du Pont, product name "Kapton 100H").

Example 25 The adhesive composition AD1 was applied on the intermediate support layer 4 made of a 12 μm thick PET film (manufactured by Toray Corporation, product name “Lumirror #12-S10”) so that the thickness of the adhesive layer was 50 μm. Next, put it into a dryer and dry the diluted solvent at 50-110° C., and at the same time cause crosslinking reaction to form a heat-peelable adhesive layer. The PET release film on one side of the acrylic substrate 1 was peeled off, and the substrate 1 was attached to the side of the PET film of the intermediate support layer 4 coated with a heat-peelable adhesive layer. Peel off the other PET release film of substrate 1, attach a PET film with a thickness of 50 μm as the support layer 3, and maintain it at 40°C for 3 days to obtain an adhesive tape with the layer composition shown in Figure 1(C).

Example 26 Adhesive composition AD1 was coated on a 50 μm thick PET release film (manufactured by Fujimori Kogyo Co., Ltd., product name "FILMBYNA (registered trademark) KF#50") that had undergone silicone release treatment so that the thickness of the adhesive layer was 50 μm. . Next, put it into a dryer and dry the diluted solvent at 50-110°C, and at the same time make it cross-linked, and make two films with heat-peelable adhesive layers formed thereon. The PET mold release film on one side of the substrate is peeled off, and the first heat-peelable adhesive layer is transferred to form the first adhesive layer. On the first adhesive layer, the above-mentioned PET mold release film was bonded on the side of the mold release treatment surface. Further peel off the PET mold release film on the other side of the base material, transfer the second heat-peelable adhesive layer to form a second adhesive layer, and place the above-mentioned PET mold release film on the release treatment side on the second adhesive layer fit. Thereafter, it was maintained at 40° C. for 3 days to obtain an adhesive tape. In addition, in the height difference followability test, the PET mold release film on the opposite side of the adhesive surface was also peeled off by heating. In the adhesive force measurement, the PET mold release film on the opposite side of the adhesive surface was peeled off, and a 50 μm PET film was attached. Film (manufactured by Toray Corporation, product name "Lumirror #50-S10") was measured. Table 10 shows the results of Examples 23 to 26 above.

[Table 10] Table 10 Example 23 Example 24 Example 25 Example 26 1st adhesive layer 2nd adhesive layer Substrate AS1 (thickness 200μm) Adhesive layer AD1 AD1 AD1 support layer none P.I. PET none layer composition Figure 1(A) Figure 1(B) Figure 1(C) Figure 1(D) Test temperature (℃) 150 150 150 150 150 height difference followability Before heating A A A A A after heating A A A A A Adhesion [N/10mm] initial 9.1 2.94 3.48 3.8 4.84 after heating 22.58 21.39 2.51 3.39 3.94 Thermal peeling temperature (°C) 220°C 220°C 220°C 220°C 220°C Hot Peelability A A A A A

As shown in Table 10 above, excellent step followability and thermal peelability were exhibited even if the tape structures were different. Moreover, heat-peelability can be provided to both surfaces by providing a heat-peelable adhesive layer on both surfaces.

1: Substrate 2: Heat-peelable adhesive layer 3: support layer 4: Intermediate support layer 5: The second adhesive layer

1(A) to (D) are schematic cross-sectional views showing an example of the layer constitution of the heat-peelable adhesive tape of the present invention.

1: Substrate

2: Heat-peelable adhesive layer

3: support layer

4: Intermediate support layer

5: The second adhesive layer

Claims (8)

A heat-peelable adhesive tape comprising a base material and a heat-peelable adhesive layer on at least one side of the base material, characterized in that: of the substrate (a) The tensile strength at 100% elongation is 0.9 MPa or less, (b) The compressive stress at 50% compression is 2.0MPa or less, (c) The value of tanδ at the maximum temperature when the heat-peelable adhesive tape is used at 100°C or higher obtained by dynamic viscoelasticity measurement at a frequency of 10 Hz is 0.80 or less, The heat-peelable adhesive layer (d) Contains thermally expandable pellets whose foaming start temperature is above the maximum temperature in use + 15°C, and the content of the thermally expandable pellets is 6 parts by mass relative to 100 parts by mass of the adhesive component forming the heat-peelable adhesive layer. The range of more than 50 parts by mass is not less than 50 parts by mass. The heat-peelable adhesive tape according to claim 1, wherein the substrate is a resin substrate containing at least one resin selected from the group of acrylic resin, silicone resin, and urethane resin as a main component . The heat-peelable adhesive tape according to claim 1, wherein the adhesive component contains a (meth)acrylic copolymer as a main component. The heat-peelable adhesive tape according to claim 3, wherein the (meth)acrylic copolymer contains structural units derived from acrylic acid, and the content of the structural units derived from acrylic acid is relative to that of the (meth)acrylic copolymer. 100% by mass of the total monomer units is 2% by mass or more. The heat-peelable adhesive tape according to claim 1, wherein a resin film different from the base material is provided as a supporting layer on at least one side of the base material. The heat-peelable adhesive tape according to claim 5, wherein the resin contained in the resin film is selected from polyimide resin, fluororesin, polyester resin, polyether ether ketone resin, polyphenylene sulfide resin and polycycloolefin at least one of the group of resins. The heat-peelable adhesive tape according to claim 1, wherein the heat-peelable adhesive layer formed on one side of the substrate is used as the first adhesive layer, and has a second surface on the other side different from the one side of the substrate. 2. Adhesive layer, the second adhesive layer is an adhesive layer of the same or different composition as the first adhesive layer. The heat-peelable adhesive tape according to any one of Claims 1 to 7 is used in the manufacturing steps of members with unevenness on the surface.

Images