TW202239912A - Adhesive sheet which comprises an adhesive layer containing thermal expandable microspheres and excellent in pickup property when an adherend is peeled off - Google Patents

Abstract

The present invention provides an adhesive sheet comprising an adhesive layer containing thermal expandable microspheres and excellent in pickup property when an adherend is peeled off. The adhesive sheet of the present invention comprises an adhesive layer containing thermal expandable microspheres. The adhesive expansibility of the adhesive layer heated to the foaming peak temperature of the thermally expandable microsphere (thickness of the adhesive layer heated to the foaming peak temperature of the thermally expandable microsphere/thickness of the adhesive layer at 23 ℃), is 1.1 to 2. In one embodiment, the adhesive layer includes an active energy ray curable adhesive.

Description

Adhesive sheet

The present invention relates to an adhesive sheet.

As an adhesive sheet used for the purpose of temporarily fixing a processed product (such as an electronic part) in a step of manufacturing an electronic part, it is known that it exhibits adhesiveness during temporary fixing and exhibits peeling when fixing is not required Easy-to-peel adhesive sheet. As one of such adhesive sheets, an adhesive sheet comprising heat-expandable microspheres in an adhesive layer is being studied (for example, Patent Document 1). The adhesive sheet can express the desired adhesive force to fix the workpiece at a relatively low temperature represented by normal temperature, and on the other hand, by heating, the heat-expandable microspheres expand and generate Concave-convex, thereby reducing the adhesive force, and it is easy to peel off the processed product.

After temporarily fixing the workpiece as described above, the workpiece may be picked up from above and transferred (for example, suction transfer) during peeling. At this time, mainly due to the non-uniform deformation of the surface of the adhesive layer, there is a problem that the workpiece is tilted and pick-up failure occurs. Such a problem becomes remarkable with the miniaturization of processed products (for example, electronic parts). [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2001-131507

[Problem to be solved by the invention]

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to provide an adhesive sheet having an adhesive layer containing heat-expandable microspheres and having excellent pick-up properties when peeled off from an adhesive. [Technical means to solve the problem]

The adhesive sheet of the present invention has an adhesive layer comprising heat-expandable microspheres, and in the adhesive layer, the expansion property of the adhesive when heated to the foaming peak temperature of the heat-expandable microspheres (heating to the foaming temperature of the heat-expandable microspheres) The thickness of the adhesive layer at the peak temperature/thickness of the adhesive layer at 23°C) is 1.1-2. In one embodiment, the adhesive layer includes an active energy ray-curable adhesive. In one embodiment, the active energy ray-curable adhesive includes a polymer and an oligomer as an active energy ray-reactive compound. In one embodiment, the active energy ray-curable adhesive includes an active energy ray-reactive polymer. In one embodiment, the active energy ray-curable adhesive includes a photopolymerization initiator selected from the group consisting of alkylphenone-based photopolymerization initiators, hydroxyacetophenone-based photopolymerization initiators, and hydroxyacetophenone-based photopolymerization initiators. agent, hydroxyketone-based photopolymerization initiator, aminoacetophenone-based photopolymerization initiator, and benzoyl ketal-based photopolymerization initiator. In one embodiment, the active energy ray-curable adhesive contains an adhesive agent. In one embodiment, the content ratio of the tack-imparting agent is 1 to 100 parts by weight with respect to 100 parts by weight of the polymer in the active energy ray-curable adhesive. In one embodiment, the elastic modulus of the adhesive layer obtained by nanoindentation at a temperature 10°C lower than the foaming initiation temperature of the expandable microspheres is 3.0 MPa to 400 MPa. In one embodiment, the cumulative volume particle diameter D50 of the heat-expandable microspheres is 13 μm to 50 μm. In one embodiment, the peak width of the particle size distribution of the heat-expandable microspheres is 20 μm or less. In one embodiment, the content ratio of the thermally expandable microspheres is 5 to 50 parts by weight with respect to 100 parts by weight of the polymer in the adhesive. In one embodiment, the initial adhesive force when the adhesive layer of the adhesive sheet is attached to SUS304BA is 0.5 N/20 mm to 25 N/25 mm. In one embodiment, the above-mentioned adhesive sheet further includes a substrate, and the above-mentioned adhesive layer is disposed on at least one side of the substrate. According to another aspect of the present invention, a method for manufacturing an electronic component is provided. The manufacturing method includes: a step of attaching the adhesive sheet to the device; a step of irradiating the adhesive sheet with ultraviolet rays; and a step of heating the adhesive sheet and peeling the device from the adhesive sheet. [Effect of Invention]

According to the present invention, it is possible to provide an adhesive sheet having an adhesive layer containing heat-expandable microspheres and having excellent pick-up properties when peeled off from an adherend.

A. Outline of Adhesive Sheet FIG. 1( a ) is a schematic cross-sectional view of an adhesive sheet according to one embodiment of the present invention. The adhesive sheet 100 includes an adhesive layer 10 . The adhesive sheet of the present invention may be composed of only the adhesive layer 10, and may further include any appropriate layer in addition to the adhesive layer.

Fig. 1(b) is a schematic sectional view of an adhesive sheet according to another embodiment of the present invention. The adhesive sheet 200 further includes a substrate 20 , and the adhesive layer 10 is disposed on at least one side of the substrate 20 . Fig. 1(c) is a schematic cross-sectional view of an adhesive sheet according to still another embodiment of the present invention. The adhesive sheet 300 includes an adhesive layer 10 and another adhesive layer 30 disposed on at least one side of the adhesive layer 10 . The base material 20 can be disposed between the adhesive layer 10 and another adhesive layer 30 as shown in the figure. Although not shown, the base material can also be omitted, and the adhesive sheet can be composed of an adhesive layer and another adhesive layer. material. Also, although not shown, the adhesive sheet may further include an elastic layer (item E described later) capable of imparting elasticity to the adhesive sheet, and a release film (item F described later) releasably disposed on the adhesive layer. ) etc. as a layer other than the adhesive layer. Also, an adhesive layer may be disposed on both sides of the base material.

In one embodiment, the above-mentioned adhesive layer may be an adhesive layer that can be hardened by irradiation of active energy rays. The hardenable adhesive layer may contain an active energy ray-curable adhesive.

The adhesive layer included in the adhesive sheet of the present invention contains heat-expandable microspheres. The heat-expandable microspheres can be expanded at a predetermined temperature. For the adhesive layer containing such heat-expandable microspheres, the heat-expandable microspheres are expanded by heating, thereby producing unevenness on the adhesive surface (ie, the surface of the adhesive layer), thereby reducing or disappearing the adhesive force. When the adhesive sheet of the present invention is used, for example, as a sheet for temporarily fixing a workpiece during processing of electronic parts (for example, a printed circuit board), when a predetermined processing (for example, cutting) is performed on the workpiece It shows the adhesiveness required for temporary fixation, and when the processed object is peeled off from the adhesive sheet after processing, the adhesive force is reduced or disappeared by heating, thus exhibiting good peelability. In one embodiment, when the above-mentioned adhesive layer is curable, after the above-mentioned processing, the adhesive layer is cured by an active energy ray, and then heated to peel off the workpiece. By carrying out the sticking operation before hardening, the adhesive sheet can be stuck with good unevenness followability. In another embodiment, when the above-mentioned adhesive layer is hardenable, after the adhesive layer is hardened by active energy rays, the attaching operation to the workpiece is performed.

In the above-mentioned adhesive layer, the expansion property of the adhesive when heated to the peak foaming temperature of the heat-expandable microspheres is 1.1-2. In this specification, the adhesive expansion property refers to the thickness of the adhesive layer (single layer) at 20°C (initial thickness) and the thickness when heated to the peak expansion temperature of thermally expandable microspheres (thickness at peak expansion), Calculated by the calculation formula [thickness at peak foaming/initial thickness]. "Foaming peak temperature" refers to the temperature at which the thickness of the adhesive sheet becomes the maximum when the adhesive sheet is heated at a predetermined temperature (20°C to 300°C) for 1 minute. Here, "the temperature at which the thickness becomes the maximum" refers to the temperature at which the thickness becomes the maximum due to the expansion of the heat-expandable microspheres. The band thins again. In addition, the temperature at which the thickness of the adhesive layer is 110% of the thickness (initial thickness) of the adhesive layer at 20° C. is defined as the “foaming start temperature” described later. Furthermore, when the adhesive layer can be cured, both "peak foaming temperature" and "foaming start temperature" are measured after active energy ray irradiation (for example, UV irradiation (1000 mJ/cm ² )) for heating.

In the present invention, the expansion property of the adhesive is specified as described above, whereby the shape change in the thickness direction of the adhesive layer during heating is suppressed, thereby improving the uniformity of the shape change. On the other hand, it is possible to preferably produce the fine concave-convex shape brought about by the heat-expandable microspheres. If the adhesive sheet of this invention which has such a feature is used, even when a to-be-processed article is peeled off, this to-be-processed article will not incline, and as a result, pick-up failure can be prevented. The expansion property of the adhesive when heated to the peak foaming temperature of the heat-expandable microspheres is preferably 1.1-1.8, more preferably 1.1-1.6, and still more preferably 1.1-1.5. If it is such a range, the said effect is remarkable. The expansion property of the adhesive can be determined, for example, by the elastic modulus of the adhesive layer (for example, the elastic modulus obtained by nanoindentation method at a temperature 10°C lower than the temperature at which foaming starts), the size of thermally expandable microspheres Characteristics (for example, 50% particle size, particle size distribution), the amount of thermally expandable microspheres added, etc. to control.

When the adhesive layer of the above-mentioned adhesive sheet is attached to SUS304BA, the initial adhesive force is preferably 0.5 N/20 mm to 25 N/20 mm, more preferably 1 N/20 mm to 20 N/20 mm, and more preferably The best is 1.5 N/20 mm to 18 N/20 mm, and the best is 2 N/20 mm to 15 N/20 mm. If it is such a range, the adhesive sheet which expresses favorable adhesiveness can be obtained, for example as a temporary fixing sheet used for manufacture of an electronic component. In this specification, the initial adhesive force refers to the adhesive force before the heat-expandable microspheres are foamed (also, in the case where the above-mentioned adhesive layer can be hardened, it is before hardening). Adhesive force is measured by the method according to JIS Z 0237:2000 (lamination condition: 2 kg roller back and forth once, peeling speed: 300 mm/min, peeling angle 180°) in an environment of 23°C.

In one embodiment, when the above-mentioned adhesive layer can be hardened, the adhesive sheet is attached to SUS304BA by irradiating the adhesive sheet with active energy rays (for example, ultraviolet rays with a cumulative light intensity of 1000 mJ/cm ² ). The adhesion force at 23°C is preferably 0.1 N/20 mm to 25 N/20 mm, more preferably 0.2 N/20 mm to 15 N/20 mm, and more preferably 0.2 N/20 mm to 10 N/20 mm, preferably 0.2 N/20 mm to 5 N/20 mm. As a method of irradiating active energy rays, for example, after attaching an adhesive sheet to SUS304BA, use an ultraviolet irradiation machine "UM810 (high-pressure mercury lamp light source)" (manufactured by Nitto Seiki Co., Ltd.) to irradiate the accumulated light amount from the side of the adhesive sheet 1000 mJ/cm ² UV method.

The thickness of the adhesive sheet is preferably from 30 μm to 500 μm, more preferably from 40 μm to 300 μm, and still more preferably from 50 μm to 200 μm.

In one embodiment, the above-mentioned adhesive sheet can be used as a fixing material for temporarily fixing devices when manufacturing electronic parts. In one embodiment, there is provided a method of manufacturing an electronic component, which includes: a step of attaching the above-mentioned adhesive sheet to a device; a step of irradiating the adhesive sheet with ultraviolet rays; thereafter, heating the adhesive sheet to automatically A step of peeling off the device from the adhesive sheet. It is preferable to adjust the ultraviolet irradiation conditions in the "step of irradiating the adhesive sheet with ultraviolet rays" to control the above-mentioned "expansion of the adhesive when heated to the peak foaming temperature of the heat-expandable microspheres". The amount of ultraviolet irradiation is, for example, 10 mJ/cm ² to 1500 mJ/cm ² .

B. Adhesive Layer The above-mentioned adhesive layer contains an adhesive for imparting adhesiveness and thermally expandable microspheres.

The normal modulus of elasticity obtained by the nanoindentation method at 23° C. of the adhesive layer is preferably 1.0 MPa˜20.0 MPa, more preferably 3.0 MPa˜15.0 MPa. "Normal elastic modulus obtained by nanoindentation method" refers to the elastic modulus before irradiation with active energy rays. The method of measuring the normal elastic modulus obtained by the nanoindentation method will be described later.

The elastic modulus of the adhesive layer obtained by nano-indentation at a temperature 10°C lower than the foaming initiation temperature of the heat-expandable microspheres is preferably 3.0 MPa-400 MPa, more preferably 3.0 MPa-320 MPa , and more preferably 3.0 MPa to 280 MPa, most preferably 6.0 MPa to 200 MPa. If it is within this range, it is possible to moderately restrain the expansion of the heat-expandable microspheres, thereby better adjusting the expansion of the adhesive, preventing the inclination of the adherend during peeling, and showing sufficient heat peelability. Adhesive sheet. The "elastic modulus obtained by the nanoindentation method at a temperature 10° C. lower than the foaming initiation temperature of the heat-expandable microspheres" can be adjusted by any appropriate method. For example, the modulus of elasticity can be within an appropriate range depending on the structure of the adhesive component. In one embodiment, an adhesive layer is formed by using an active energy ray-curable adhesive as an adhesive, and the adhesive layer is irradiated with active energy rays (for example, ultraviolet rays) to adjust the "rather thermally expandable microspheres". Elastic modulus obtained by nanoindentation method at a temperature 10°C lower than the foaming initiation temperature". In this embodiment, as the active energy ray-curable adhesive, an adhesive containing an active energy ray-reactive compound (monomer or oligomer) or an active energy ray-reactive polymer is used. The amount of carbon-carbon multiple bonds, the amount of adhesive added, the amount of active energy ray irradiation, etc., can be adjusted. "Obtained by nano-indentation method at a temperature 10°C lower than the foaming initiation temperature of thermally expandable microspheres modulus of elasticity".

The thickness of the adhesive layer is preferably from 5 μm to 200 μm, more preferably from 15 μm to 100 μm, further preferably from 20 μm to 60 μm, and most preferably from 25 μm to 45 μm.

The surface roughness Ra of the adhesive layer before the heat-expandable microspheres are expanded at an ambient temperature of 25° C. is preferably 500 nm or less, more preferably 400 nm or less, further preferably 300 nm or less. If it is such a range, the adhesive sheet which can reduce the unevenness|corrugation which arises in the attachment surface of an adherend can be obtained. In addition, the said surface roughness Ra can become an appropriate value by adjusting content, average particle diameter, etc. of the heat-expandable microsphere contained in an adhesive layer. The surface roughness Ra can be measured in accordance with JIS B 0601:1994.

The surface roughness Ra of the adhesive layer after heating the adhesive sheet of the present invention to foam the heat-expandable microspheres is preferably 1 μm or more, more preferably 3 μm or more. If it is such a range, the adhesive force will fall or disappear after heating, and the adhesive sheet which can peel off an adherend easily can be obtained. In addition, here, the surface roughness Ra of an adhesive layer means the surface roughness Ra of the adhesive layer after heating in the state without an adherend.

B-1. Adhesive As the adhesive constituting the above-mentioned adhesive layer, any appropriate adhesive can be used as long as the effect of the present invention can be obtained. In one embodiment, as the adhesive, a curable adhesive, preferably an active energy ray curable adhesive is used. In another embodiment, a pressure-sensitive adhesive is used as the adhesive. As a pressure-sensitive adhesive, an acrylic adhesive, a rubber adhesive, etc. are mentioned, for example. It is preferable to use a hardening adhesive. If a hardening adhesive is used, it is better to control the expansion of the adhesive.

(Active energy ray hardening adhesive) Examples of the above-mentioned active energy ray-curable adhesives include ultraviolet curing systems (Kato Kiyomi, published by the General Technology Center, (1989)), photocuring technology (Edited by the Technical Information Association (2000)), Japanese Patent Laid-Open Adhesives described in Publication No. 2003-292916, Japanese Patent No. 4151850, etc. More specifically, an adhesive (R1) containing a polymer as a parent agent and an active energy ray-reactive compound (monomer or oligomer), an adhesive (R2) containing an active energy ray-reactive polymer )Wait. In one embodiment, the adhesive (R1) contains a polymer and an oligomer which is an active energy ray reactive compound.

The polymer used as the above-mentioned masterbatch may, for example, be natural rubber, polyisobutylene rubber, styrene-butadiene rubber, styrene-isoprene-styrene block copolymer rubber, recycled rubber, butyl rubber , polyisobutylene rubber, nitrile rubber (NBR (Nitrile Butadiene Rubber; nitrile rubber)) and other rubber-based polymers; silicone-based polymers; acrylic-based polymers, etc. These polymers can be used individually or in combination of 2 or more types.

Examples of the active energy ray reactive compound include photoreactive compounds containing a plurality of functional groups having carbon-carbon multiple bonds, such as acryl, methacryl, vinyl, allyl, and ethynyl. monomer or oligomer. Among them, it is preferable to use a compound having an ethylenically unsaturated functional group, and it is more preferable to use a (meth)acrylic compound having an ethylenically unsaturated functional group. A compound having an ethylenically unsaturated functional group is easy to generate free radicals by ultraviolet rays, so if this compound is used, an adhesive layer that can be hardened in a short time can be formed. Also, if a (meth)acrylic compound having an ethylenically unsaturated functional group is used, an adhesive having moderate hardness (specifically, a hardness at which heat-expandable microspheres can be well-foamed) can be formed after curing. Floor. Specific examples of photoreactive monomers or oligomers include urethane oligomers, urethane (meth)acrylates, trimethylolpropane tri(meth)acrylic acid ester, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate base) acrylate, 1,4-butanediol di(meth)acrylate, 1,6-butanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, etc. base) acryl compound; the 2-5 polymers of the (meth)acryl compound; etc. These compounds can be used individually or in combination of 2 or more types. Moreover, the kind of the functional group in an active energy ray reactive compound may be only 1 kind, and may be 2 or more kinds. When it has two or more kinds of functional groups, it becomes easy to control the characteristic of an adhesive layer. In this specification, an oligomer refers to a polymer having a molecular weight of less than 3.0×10 ⁴ . The molecular weight of the above-mentioned oligomer is preferably at least 100, preferably at most 1.0×10 ⁴ . As the molecular weight of the oligomer, the weight average molecular weight (Mw) in terms of standard polystyrene obtained by gel permeation chromatography (GPC) or the molecular weight calculated from the chemical formula was used.

When an oligomer is used as the active energy ray-reactive compound, the number of functional groups per molecule of the oligomer (the number of functional groups having a carbon-carbon multiple bond) is preferably 7 or more, more preferably 8 or more, and further Preferably it is 9 or more, especially preferably 10 or more. If it is within such a range, the modulus of elasticity can be adjusted preferably, and an adhesive layer that can exhibit better adhesive swelling properties can be obtained. The upper limit of the number of functional groups is preferably 20.

Further, as the above-mentioned active energy ray reactive compound, monomers such as epoxidized butadiene, glycidyl methacrylate, acrylamide, and vinylsiloxane; or oligomers composed of these monomers can be used. The adhesive (R1) containing these compounds can be cured by high-energy rays such as ultraviolet rays and electron beams.

Furthermore, as the above-mentioned active energy ray reactive compound, a mixture of organic salts such as onium salts and a compound having a plurality of heterocycles in the molecule can be used. For this mixture, by irradiation of active energy rays (for example, ultraviolet rays, electron beams), the organic salt is cracked to generate ions, which become the initial species and cause the ring-opening reaction of the heterocyclic ring, thereby forming a three-dimensional network structure. Examples of the above-mentioned organic salts include iodonium salts, phosphonium salts, antimony salts, permeic acid salts, and borates. Examples of the heterocycle in the compound having a plurality of heterocycles in the molecule include oxirane, oxetane, oxolane, thiirane, and aziridine. Wait.

In the adhesive (R1) containing the above-mentioned polymer as the base agent and the active energy ray-reactive compound, the content ratio of the active energy ray-reactive compound is preferably 5 parts by weight relative to 100 parts by weight of the polymer as the base agent. ~200 parts by weight, more preferably 10 parts by weight~150 parts by weight, still more preferably 10 parts by weight~100 parts by weight, especially preferably 10 parts by weight~80 parts by weight. If it is within such a range, the modulus of elasticity can be adjusted preferably, and an adhesive layer that can exhibit better adhesive swelling properties can be obtained. When the content ratio of the active energy ray-reactive compound is too high, there is a possibility of contamination of the adherend.

As the above-mentioned active energy ray reactive polymer, any appropriate polymer having a carbon-carbon double bond can be used.

In one embodiment, a polymer having a carbon-carbon double bond can be obtained by introducing a carbon-carbon double bond into a polymer not containing a carbon-carbon double bond by chemical modification or the like. As a specific example of the method of introducing the above-mentioned carbon-carbon double bond into a polymer not containing a carbon-carbon double bond, after polymerizing a monomer having a functional group A in a polymer not containing a carbon-carbon double bond, , so that the compound (monomer or oligomer) having a functional group B and a carbon-carbon double bond that can react with the functional group A reacts in a way that the carbon-carbon double bond does not disappear (typically condensation, addition reaction) method. Examples of the combination of the functional group A and the functional group B include a combination of a carboxyl group and an epoxy group, a combination of a carboxyl group and an aziridinyl group, a combination of a hydroxyl group and an isocyanate group, and the like. Among them, a combination of a hydroxyl group and an isocyanate group is preferable from the viewpoint of reaction traceability. In addition, as long as the combination of the above-mentioned functional groups A and B is a combination that can obtain a polymer having a carbon-carbon double bond, one of the functional groups in the above-mentioned combination can be set as the functional group A, and the other can be set as the functional group B, or the above-mentioned one functional group may be set as the functional group B and the other of the above-mentioned functional groups may be set as the functional group A. Among them, a combination in which the polymer has a hydroxyl group and the compound has an isocyanate group is preferable.

Also, when the above-mentioned polymer not containing a carbon-carbon double bond is a vinyl alcohol-based polymer (for example, polyvinyl alcohol), the vinyl alcohol-based polymer is halogenated with vinyl halides such as vinyl bromide, allyl bromide, etc. The method of allyl reaction can also be mentioned as a suitable example. The above reactions are carried out under appropriate basic conditions. Also, for example, a method for producing a polymer having a carbon-carbon double bond using a polymer-producing microorganism as disclosed in Japanese Patent No. 4502363 may also be used. Various conditions such as microorganism species and microorganism culture conditions in this method are set by adopting the conditions described in the above-mentioned Japanese Patent Gazette, or making appropriate changes within the scope of the technical knowledge of the practitioner.

The molar ratio (MA/MB) of the molar (MA) of the functional group A to the molar (MB) of the functional group B is preferably at least 0.2, more preferably at least 0.5, still more preferably at least 0.7, and most preferably 1 or more. If it is such a range, the polymer which has a carbon-carbon double bond can be obtained with good reactivity. Moreover, the molar ratio (MA/MB) is preferably 2 or less, more preferably 1.5 or less, still more preferably 1.3 or less, particularly preferably 1.1 or less. Also, from the viewpoint of increasing the chance of contact between the functional group A and the functional group B, more compounds containing the functional group B having a carbon-carbon double bond can be formulated. In this case, the molar ratio (MA/MB) is preferably less than 1 (preferably less than 0.99, more preferably less than 0.95). Alternatively, when the functional group A is used for other reactions (crosslinking reaction with a crosslinking agent, etc.), the molar ratio (MA/MB) is preferably greater than 1. The compounding amount of the compound having the functional group B is preferably at least 1 part by weight, more preferably at least 1 part by weight, relative to 100 parts by weight of the polymer having the functional group A, within the range satisfying the above molar ratio (MA/MB). 5 parts by weight or more, more preferably 10 parts by weight or more, more preferably 12 parts by weight or more, still more preferably 15 parts by weight or more, still more preferably 18 parts by weight or more, especially preferably 21 parts by weight or more, Most preferably it is 23 parts by weight or more. Furthermore, the compounding amount of the compound having the functional group B is preferably 40 parts by weight or less, more preferably 35 parts by weight or less, further preferably 30 parts by weight or less, and most preferably 100 parts by weight of the polymer having the functional group A. 25 parts by weight or less.

Also, the polymer having a carbon-carbon double bond may be, for example, a diene polymer (eg, a conjugated diene polymer). The diene-based polymer may be a polymer obtained by polymerizing or copolymerizing a diene (for example, a conjugated diene). Examples of diene polymers include butadiene polymers such as polybutadiene and styrene-butadiene copolymers; and isoprene polymers such as polyisoprene and styrene-isoprene copolymers. Polymers; Chloroprene-based polymers such as polychloroprene; etc.

Also, the carbon-carbon double bond is more preferably an external double bond than an internal double bond from the viewpoint of reactivity. Here, the internal double bond refers to a double bond that exists in a state of entering the interior of the main chain of the polymer or oligomer. The two carbon atoms of the carbon-carbon double bond form the backbone. Moreover, the external double bond means the double bond which exists outside the molecular chain (for example, main chain) of a polymer or an oligomer. Furthermore, when a carbon-carbon double bond exists at the end of the main chain of a polymer or an oligomer, the double bond is an external double bond.

The content ratio of the active energy ray reactive polymer (preferably a polymer having a carbon-carbon double bond) is preferably 10 parts by weight or more, more preferably 50 parts by weight or more, and even more preferably 100 parts by weight of the adhesive layer. Preferably at least 70 parts by weight, more preferably at least 90 parts by weight, still more preferably at least 95 parts by weight, still more preferably at least 97 parts by weight, particularly preferably at least 99 parts by weight, most preferably at least 99 parts by weight to 100 parts by weight parts by weight. If it is such a range, the adhesive layer whose elastic modulus can be adjusted suitably can be obtained.

In one embodiment, the above-mentioned active energy ray-reactive polymer may, for example, be an active energy ray containing acryl, methacryl, vinyl, allyl, ethynyl, etc. and has a carbon-carbon multiple bond. Polymers with reactive functional groups. It is preferable to use a compound (polymer) having an ethylenically unsaturated functional group, and it is more preferable to use a (meth)acrylic polymer having an acryl group or a methacryl group. As a specific example of the polymer which has an active energy ray reactive functional group, the polymer etc. which consist of polyfunctional (meth)acrylate are mentioned. The polymer composed of the polyfunctional (meth)acrylate preferably has an alkyl ester having 4 or more carbon atoms in the side chain, more preferably has an alkyl ester having 6 or more carbon atoms, and further preferably has The alkyl ester having 8 or more carbon atoms is particularly preferably an alkyl ester having 8 to 20 carbon atoms, most preferably an alkyl ester having 8 to 18 carbon atoms. In the above polymer, the content ratio of the structural unit having an alkyl ester having 4 or more carbon atoms as a side chain is preferably 30% by weight or more, more preferably 50% by weight to 80% by weight, relative to all structural units constituting the polymer. weight%.

The above-mentioned adhesive (R2) containing an active energy ray-reactive polymer may further contain the above-mentioned active energy ray-reactive compound (monomer or oligomer).

The above-mentioned active energy ray-curable adhesive can be cured by irradiation of active energy ray. In the adhesive sheet of the present invention, the adherend can be adhered to the adherend before the adhesive is hardened, and then the adhesive is irradiated with active energy rays to harden the adhesive. Examples of active energy rays include γ-rays, ultraviolet rays, visible rays, infrared rays (heat rays), radio frequency waves, α-rays, β-rays, electron beams, plasma streams, ionizing radiation, and particle beams. Conditions such as the wavelength of the active energy ray and the irradiation dose can be set to any appropriate conditions according to the composition of the adhesive and the like. For example, the adhesive can be hardened by irradiating ultraviolet rays with an irradiation dose of 10-1000 mJ/cm ² .

(additive) The said adhesive agent may contain arbitrary appropriate additives as needed. Examples of such additives include photopolymerization initiators, crosslinking agents, tackifiers, plasticizers, pigments, dyes, fillers, anti-aging agents, conductive materials, antistatic agents, ultraviolet absorbers, photostabilizers, etc. Agents, peel regulators, softeners, surfactants, flame retardants, antioxidants, etc.

In one embodiment, the above-mentioned adhesive contains an adhesive imparting agent. When an adhesive agent is contained in the adhesive agent, an adhesive layer in which the thermally expandable microspheres are easily foamed can be formed. In addition, it is possible to obtain an adhesive sheet in which the expansion property of the adhesive is properly adjusted so that the adherend can be prevented from tilting during peeling.

Any appropriate tackifier can be used as the tackifier. As the tackifier, for example, tackifier resin is used. Specific examples of tackifying resins include rosin-based tackifying resins (for example, unmodified rosin, modified rosin, rosin phenolic resins, rosin ester-based resins, etc.), terpene-based tackifying resins (such as terpene olefin-based resin, terpene-phenolic resin, styrene-modified terpene-based resin, aromatic-modified terpene-based resin, hydrogenated terpene-based resin), hydrocarbon-based tackifying resin (for example, aliphatic hydrocarbon resin, fatty Family-based cyclic hydrocarbon resins, aromatic-based hydrocarbon resins (such as styrene-based resins, xylene-based resins, etc.), aliphatic-aromatic petroleum resins, aliphatic-alicyclic petroleum resins, hydrogenated hydrocarbon resins, coumarone-based resins, coumarone-indene-based resins, etc.), phenolic tackifier resins (for example, alkylphenol-based resins, xylene formaldehyde-based resins, resols, novolaks, etc.), ketone-based Adhesive resins, polyamide-based adhesive resins, epoxy-based adhesive resins, elastomeric adhesive resins, etc. Among them, rosin-based tackifying resins, terpene-based tackifying resins, or hydrocarbon-based tackifying resins (styrene-based resins, etc.) are preferable. The tackifier can be used alone or in combination of two or more.

In one embodiment, a rosin-based tackifying resin and/or a terpene-based tackifying resin is used. In the above-mentioned active energy ray-curing type adhesive agent composed of these adhesive-imparting resins and an adhesive agent containing a (meth)acrylic compound (consisting of a (meth)acrylic active energy ray-reactive compound or an active energy ray-reactive polymer), agent; the above-mentioned acrylic adhesive, etc.) is particularly useful when used in combination. More specifically, since the above-mentioned tackifying resin has good compatibility with an adhesive containing a (meth)acrylic compound, if the tackifying resin is used, it is difficult to generate adhesive force between minute regions on the surface of the adhesive layer. Differences, it is possible to obtain an adhesive sheet suitable for handling small adherends (processed objects).

The amount of the above-mentioned tackifier to be added is preferably 1 to 100 parts by weight, more preferably 1 to 80 parts by weight, and still more preferably 1 to 50 parts by weight relative to 100 parts by weight of the polymer in the adhesive. parts, more preferably 5 to 30 parts by weight, particularly preferably 5 to 20 parts by weight, most preferably 10 to 20 parts by weight.

The softening point of the above-mentioned tackifier is preferably 200°C or lower, more preferably 60°C to 150°C. If it is within such a range, it is possible to form an adhesive layer that is hard when the adherend is processed and becomes soft by heating for foaming the above-mentioned heat-expandable microspheres.

Any appropriate photopolymerization initiator can be used as the above-mentioned photopolymerization initiator. Preferably, as the photopolymerization initiator, it is selected from the group consisting of alkylphenone-based photopolymerization initiators, hydroxyacetophenone-based photopolymerization initiators, hydroxyketone-based photopolymerization initiators, aminoacetophenone It is at least one of the group consisting of a photopolymerization initiator and a benzoyl ketal-based photopolymerization initiator. When such a photopolymerization initiator is used, control of the curing reaction becomes easy. More specifically, if the above-mentioned photopolymerization initiator is used, hardening can be obtained only when irradiated with light in the ultraviolet region included only in special lighting and does not accidentally harden due to widely used light such as lighting light. Therefore, the control of the hardening reaction of the adhesive layer becomes easy. Moreover, if the said photoinitiator is used, the adhesive layer which can harden rapidly and uniformly can be formed. When such an adhesive layer is formed, the heat-expandable microspheres can be uniformly expanded at a desired timing, and the inclination of the adherend (wafer) during heating can be prevented.

B-2. Heat-expandable microspheres Heat-expandable microspheres are microspheres that can expand or foam by heating. The adhesive sheet having the adhesive layer containing the heat-expandable microspheres is heated to generate unevenness on the sticking surface and the adhesive force is reduced, so it has sufficient adhesive force when the adhesive force is required, and it has sufficient adhesive force when it needs to be peeled off. Excellent peelability.

The content ratio of the above-mentioned heat-expandable microspheres can be appropriately set according to the desired reduction in adhesive force and the like. The content ratio of heat-expandable microspheres is preferably 5 to 50 parts by weight, more preferably 10 to 50 parts by weight, and still more preferably 10 to 40 parts by weight relative to 100 parts by weight of the polymer in the adhesive. part, preferably 10 to 30 parts by weight. If it is within such a range, a smooth adhesive layer can be formed before foaming the heat-expandable microspheres, and an adhesive layer having a favorable uneven surface can be formed after foaming the heat-expandable microspheres. In addition, it is possible to obtain an adhesive sheet in which the expansion property of the adhesive is preferably adjusted to prevent the inclination of the adherend at the time of peeling.

Any appropriate heat-expandable microspheres can be used as the above-mentioned heat-expandable microspheres. As the above-mentioned heat-expandable microspheres, for example, microspheres containing a substance that easily expands by heating in an elastic shell can be used. Such heat-expandable microspheres can be produced by any appropriate method, such as coacervation method, interfacial polymerization method and the like.

Examples of substances that easily expand upon heating include propane, propylene, butene, n-butane, isobutane, isopentane, neopentane, n-pentane, n-hexane, isohexane, heptane, octane, and Alkanes, petroleum ether, methane halides, tetraalkylsilanes and other low-boiling liquids; azodicarbonamides vaporized by thermal decomposition; etc.

Examples of the material constituting the shell include polymers composed of the following monomers: nitriles such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethoxyacrylonitrile, and fumaronitrile. Monomer; Acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid and other carboxylic acid monomers; vinylidene chloride; vinyl acetate; (meth)methyl acrylate, (methyl ) ethyl acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, iso-(meth)acrylate, cyclohexyl (meth)acrylate (Meth)acrylic esters such as esters, benzyl (meth)acrylate, β-carboxyethyl acrylate, etc.; styrene monomers such as styrene, α-methylstyrene, and chlorostyrene; acrylamide, substituted acrylamide Amines, methacrylamides, substituted methacrylamides and other amide monomers; etc. The polymer composed of these monomers may be a homopolymer or a copolymer. As the copolymer, for example, vinylidene chloride-methyl methacrylate-acrylonitrile copolymer, methyl methacrylate-acrylonitrile-methacrylonitrile copolymer, methyl methacrylate-acrylonitrile copolymer substances, acrylonitrile-methacrylonitrile-itaconic acid copolymer, etc.

As the heat-expandable microspheres, an inorganic foaming agent or an organic foaming agent can be used. As an inorganic foaming agent, ammonium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonium nitrite, sodium borohydride, various azides, etc. are mentioned, for example. Moreover, as an organic foaming agent, for example, chlorofluoroalkane compounds such as trichloromonofluoromethane and dichloromonofluoromethane; azobisisobutyronitrile, azodiformamide, azodicarboxy Azo compounds such as barium acid; p-toluenesulfonylhydrazine, diphenylsulfonyl-3,3'-disulfonylhydrazine, 4,4'-oxybis(benzenesulfonylhydrazine), allylbis(sulfonylhydrazine) Hydrazine) and other hydrazine compounds; p-toluenesulfonylaminourea, 4,4'-oxybis(benzenesulfonylaminourea) and other semiurea compounds; 5-𠰌linyl-1,2,3,4 -Thiatriazole and other triazole compounds; N,N'-Dinitrosopentamethylenetetramine, N,N'-Dimethyl-N,N'-Dinitrosoterephthalamide ; and other N-nitroso compounds.

As the heat-expandable microspheres, commercially available ones can be used. Specific examples of commercially available heat-expandable microspheres include "Matsumoto Microsphere" (grades: F-30, F-30D, F-36D, F-36LV, F-50 , F-50D, F-65, F-65D, FN-100SS, FN-100SSD, FN-180SS, FN-180SSD, F-190D, F-260D, F-2800D), trade names manufactured by Japan Fillite Corporation " Expancel" (grades: 053-40, 031-40, 920-40, 909-80, 930-120), "DAIFOAM" manufactured by Kureha Chemical Industry Co., Ltd. (grades: H750, H850, H1100, S2320D, S2640D, M330, M430, M520), Sekisui Chemical Co., Ltd. "ADVANCELL" (grade: EML101, EMH204, EHM301, EHM302, EHM303, EM304, EHM401, EM403, EM501), etc.

The cumulative volume particle diameter D50 (particle diameter at 50% cumulative volume) of the thermally expandable microspheres is preferably 13 μm to 50 μm, more preferably 13 μm to 40 μm, further preferably 13 μm to 30 μm, especially Preferably, it is 15 μm to 30 μm. If it is such a range, the adhesive sheet which can prevent the inclination of the adherend at the time of peeling with the expansion property of an adhesive adjusted preferably can be obtained.

The peak width of the particle size distribution of the heat-expandable microspheres is preferably 20 μm or less, more preferably 18 μm or less, further preferably 16 μm or less. If the particle size is uniform, the uniformity of expansion due to heating is also high. Therefore, if heat-expandable microspheres showing a peak width of the particle size distribution as described above are used, the expansion property of the adhesive can be better adjusted and can be obtained. Adhesive sheet that prevents the inclination of the adherend during peeling. The lower limit of the peak width of the particle size distribution of the heat-expandable microspheres is, for example, 10 μm (preferably 8 μm, more preferably 6 μm). In this specification, "the peak width of particle size distribution" is an index which shows the distribution width of a peak, and it calculates by the following method using D84% and D16% when the cumulative frequency of a peak is made into 100%. Peak width (μm) = D84% (μm) - D16% (μm) Furthermore, the above formula is only applicable to the peak having the largest area in a group of peaks represented by a continuous curve.

The heat-expandable microspheres have a moderate strength that does not break until the volume expansion rate is preferably 5 times or more, more preferably 7 times or more, and still more preferably 10 times or more. In the case of using such heat-expandable microspheres, the adhesive force can be efficiently reduced by heat treatment.

C. Substrate As the above-mentioned substrate, for example, resin sheet, nonwoven fabric, paper, metal foil, woven fabric, rubber sheet, foamed sheet, and their laminates (especially laminates containing resin sheets) body) etc. As the resin constituting the resin sheet, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyethylene ( PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), polyamide (nylon), fully aromatic polyamide (aramid), polyimide (PI ), polyvinyl chloride (PVC), polyphenylene sulfide (PPS), fluororesin, polyether ether ketone (PEEK), etc. Examples of the nonwoven fabric include nonwoven fabrics made of heat-resistant natural fibers such as Manila hemp nonwoven fabrics, and synthetic resin nonwoven fabrics such as polypropylene resin nonwoven fabrics, polyethylene resin nonwoven fabrics, and ester resin nonwoven fabrics. Copper foil, stainless steel foil, aluminum foil, etc. are mentioned as metal foil. As paper, Japanese paper, kraft paper, etc. are mentioned.

The thickness of the above-mentioned base material can be set to any appropriate thickness according to desired strength, flexibility, purpose of use, and the like. The thickness of the substrate is preferably 1000 μm or less, more preferably 1 μm to 1000 μm, further preferably 1 μm to 500 μm, especially preferably 3 μm to 300 μm, most preferably 5 μm to 250 μm.

The aforementioned base material may be subjected to surface treatment. The surface treatment may, for example, be corona treatment, chromic acid treatment, ozone exposure, flame exposure, high-voltage electric shock exposure, ionizing radiation treatment, coating treatment with a primer, or the like.

As said organic coating material, the thing described in plastic hard coating material II (CMC publication, (2004)) is mentioned, for example. It is preferable to use a urethane polymer, more preferably a polyacrylate urethane, a polyester urethane or their precursors. This is because it is easy to apply and apply to a base material, and it is industrially selectable from various types and can be obtained at low cost. The urethane polymer is, for example, a polymer comprising a reaction mixture of an isocyanate monomer and an alcoholic hydroxyl-containing monomer (eg, a hydroxyl-containing acrylic compound or a hydroxyl-containing ester compound). The organic coating material may contain chain extenders such as polyamines, anti-aging agents, oxidation stabilizers, etc. as optional additives. The thickness of the organic coating layer is not particularly limited, for example, about 0.1 μm to 10 μm is appropriate, preferably about 0.1 μm to 5 μm, more preferably about 0.5 μm to 5 μm.

D. Another Adhesive Layer As the above another adhesive layer, any appropriate adhesive layer can be formed. As the adhesive for forming another adhesive layer, for example, rubber-based adhesives, acrylic adhesives, vinyl alkyl ether-based adhesives, silicone-based adhesives, polyester-based adhesives, polyamide-based adhesives, etc. Adhesives, urethane-based adhesives, fluorine-based adhesives, styrene-diene block copolymer-based adhesives, etc. Well-known or customary additives such as plasticizers, fillers, surfactants, anti-aging agents, and adhesion-imparting agents can be formulated in the adhesive.

The thickness of the other adhesive layer is preferably less than 300 μm, more preferably 1 μm to 300 μm, further preferably 5 μm to 100 μm.

E. Elastic layer The adhesive sheet of this invention may further have an elastic layer. The normal elastic modulus of the elastic layer obtained by the nanoindentation method at 23°C is 10.0 MPa or less, and the active energy ray (for example, ultraviolet rays with a cumulative light intensity of 1000 mJ/cm ² ) is irradiated by the nanoindentation method. A layer with a modulus of elasticity exceeding 10 MPa was obtained. The normal elastic modulus of the elastic layer obtained by nanoindentation at 23° C. is preferably 8 MPa or less, more preferably 5 MPa or less, further preferably 3 MPa or less. The elastic layer can be arranged on one side of the adhesive layer. When the adhesive sheet has a base material, the elastic layer can be disposed between the adhesive layer and the base material. By having an elastic layer, followability to an adherend improves. Also, the ratio of the adhesive layer to the adhesive sheet can be reduced, and as a result, an adhesive sheet that can be preferably deformed when heated can be obtained.

The above-mentioned elastic layer contains a base polymer, and as the base polymer, the polymers exemplified as the base polymer constituting the above-mentioned pressure-sensitive adhesive layer can be used. In one embodiment, the elastic layer may contain natural rubber, synthetic rubber, synthetic resin, or the like. Examples of the synthetic rubber and synthetic resin include nitrile-based, diene-based, and acrylic-based synthetic rubber; thermoplastic elastomers such as polyolefin-based and polyester-based; ethylene-vinyl acetate copolymer; polyurethane ; Polybutadiene; Soft PVC, etc. The base polymer constituting the elastic layer may be the same as or different from the base polymer forming the adhesive layer. Furthermore, the elastic layer and the adhesive layer can be distinguished by the difference of the base polymer and/or the presence or absence of foaming agent (the elastic layer does not contain foaming agent). More specifically, when the elastic layer and the adhesive layer are formed of different base polymers, etc., when the interface between the elastic layer and the adhesive layer can be recognized by cross-sectional observation, the interface between the elastic layer and the adhesive layer is determined by The interface is specified. Also, when the interface between the elastic layer and the adhesive layer cannot be recognized by cross-sectional observation, the region where the foaming agent is observed by cross-sectional observation is the adhesive layer.

The above-mentioned elastic layer may contain any appropriate additives as necessary. Examples of such additives include crosslinking agents, vulcanizing agents, tackifier resins, plasticizers, softeners, fillers, anti-aging agents and the like. When using a hard resin such as polyvinyl chloride as the base polymer, it is preferable to use a plasticizer and/or a softener in combination to form an elastic layer having desired elasticity.

The thickness of the elastic layer is preferably from 10 μm to 200 μm, more preferably from 20 μm to 150 μm, and still more preferably from 25 μm to 100 μm. If it is such a range, the said function of an elastic layer can fully be exhibited.

When the adhesive sheet has an elastic layer, the thickness of the adhesive layer is preferably 60% or less, more preferably 50% or less, and further preferably 50% or less of the total thickness of the laminate including the adhesive layer and the elastic layer. Below 45%, preferably below 40%. If it is within such a range, the thickness of the adhesive layer, which has a large influence on the deformation of the adhesive sheet, can be reduced, and an adhesive sheet excellent in balance between followability, deformation suppression of the adhesive layer, and heat peelability can be obtained. In addition, the thickness of the adhesive layer is preferably at least 10%, more preferably at least 12%, further preferably at least 15%, and most preferably at least 20% of the total thickness of the laminate including the adhesive layer and the elastic layer. above. Furthermore, "the total thickness of the laminate including the adhesive layer and the elastic layer" refers to the total thickness of the thickness of the single layer of the adhesive layer and the thickness of the single layer of the elastic layer. When the adhesive sheet has a base material, "comprising "A laminate of an adhesive layer and an elastic layer" refers to a laminate including an adhesive layer and an elastic layer arranged on the same side based on the base material.

F. Separator The adhesive sheet of the present invention may further include a separator as needed. At least one surface of the separator may be a peeling surface, which may be provided to protect the above-mentioned adhesive layer. The separator can be composed of any suitable material.

G. Manufacturing method of adhesive sheet The adhesive sheet of this invention can be manufactured by any appropriate method. The adhesive sheet of the present invention may, for example, be a method of directly coating a composition for forming an adhesive layer comprising an adhesive and heat-expandable microspheres on a substrate, or coating an adhesive layer-forming composition on any appropriate substrate. Composition and the method of transferring the formed coating layer to the substrate, etc. The composition for adhesive layer formation may contain arbitrary appropriate solvents. Also, after forming an adhesive coating layer from a composition containing an adhesive, the heat-expandable microspheres may be sprinkled on the adhesive coating layer, and thereafter, the heat-expandable microspheres may be embedded in the coating layer using a laminating machine or the like. In the cladding layer, an adhesive layer containing heat-expandable microspheres is thereby formed.

The content ratio of the heat-expandable microspheres in the composition for forming an adhesive layer is preferably 5% by weight to 95% by weight, more preferably 10% by weight to 70% by weight, based on the weight of the solid content of the composition for forming an adhesive layer. % by weight, and more preferably 10% by weight to 50% by weight.

When the adhesive layer has the above-mentioned elastic layer, the elastic layer can be formed, for example, by applying a composition for forming the elastic layer on the substrate or the adhesive layer.

Any appropriate coating method can be adopted as the coating method of each of the above-mentioned compositions. For example, each layer can be formed by drying after coating. As a coating method, the coating method using a multi-coater (multi-coater), a die coater, a gravure coater, an applicator, etc. is mentioned, for example. As a drying method, natural drying, heat drying, etc. are mentioned, for example. The heating temperature when heat drying is performed can be set to any appropriate temperature according to the characteristics of the substance to be dried. [Example]

Hereafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. The evaluation methods in the examples are as follows. In addition, in the following evaluation, the adhesive sheet which peeled the separator was used. Moreover, in an Example, unless otherwise indicated, "part" and "%" are based on weight.

(1) Initial adhesion Cut the adhesive sheet into a size of width: 20 mm, length: 140 mm, according to JIS Z 0237:2009, make a 2 kg roller reciprocate once and stick the adhesive surface to the SUS304BA plate of the adherend to obtain the measurement sample. This measurement sample was set in a tensile testing machine (manufactured by Shimadzu Corporation, trade name "Shimadzu Autograph AG-120kN") with a constant temperature bath. Afterwards, measure the load when the adherend is peeled from the adhesive sheet along the length direction under the conditions of peeling angle: 180° and tensile speed: 300 mm/min, and obtain the maximum load at this time (except for the initial measurement) The maximum value of the load other than the peak), and the value obtained by dividing the maximum load by the tape width is taken as the adhesive force (N/20 mm width). Furthermore, the above operation was carried out under the atmosphere of temperature: 23°C and humidity: 65%RH.

(2) Adhesive force after ultraviolet irradiation Cut the adhesive sheet into a size of width: 20 mm, length: 140 mm, according to JIS Z 0237: 2009, make a 2 kg roller reciprocate once to attach the adhesive surface to the quilt The SUS304BA plate of the adhesive body was placed for 30 minutes and then irradiated with ultraviolet light (irradiation dose 1000 mJ/cm ² ). This measurement sample was set in a tensile testing machine (manufactured by Shimadzu Corporation, trade name "Shimadzu Autograph AG-120kN") with a constant temperature bath. Afterwards, measure the load when the adherend is peeled from the adhesive sheet along the length direction under the conditions of peeling angle: 180° and tensile speed: 300 mm/min, and obtain the maximum load at this time (except for the initial measurement) The maximum value of the load other than the peak), and the value obtained by dividing the maximum load by the tape width is taken as the adhesive force (N/20 mm width). Furthermore, the above operation was carried out under the atmosphere of temperature: 23°C and humidity: 65%RH.

(3) Adhesive Expansion The adhesive sheet was cut into width: 20 mm, length: 140 mm to prepare a test piece. Preheat the 10 mm thick heat-resistant glass (140 mm×140 mm) on a hot plate (Shamal Hot Plate "HHP-411") to the specified temperature. Set the test piece on the hot plate, place a heat-resistant glass with a thickness of 10 mm to cover the test piece, leave the test piece as it is for 1 minute, measure the thickness of the test piece with a dial gauge, and obtain the adhesion The thickness of the agent layer (the thickness of the test piece (adhesive sheet) - the thickness of the base material). The above-mentioned predetermined temperature is set to 20° C. to 300° C. in units of 10° C., and the above-mentioned operation is performed for each predetermined temperature. That is, a new test piece (discontinuous use test piece) was used every predetermined temperature, and the thickness of the adhesive layer after heating was measured. As a result of these operations, the temperature at which the thickness of the adhesive layer became the maximum was taken as the foaming peak temperature. Furthermore, as a result of the above operations, the temperature at which the thickness of the adhesive layer becomes 110% of the thickness (initial thickness) of the adhesive layer at 20°C is the foaming initiation temperature of the heat-expandable microspheres. Regarding the thickness of the adhesive layer, the thickness at 20°C (initial thickness) is used, and the thickness when heated to the peak foaming temperature (thickness at peak foaming) is calculated by [thickness at peak foaming/initial thickness] formula to find the swelling property of the adhesive. Furthermore, in Examples and Comparative Examples in which the adhesive layer is an active energy ray (ultraviolet) curable adhesive, UV irradiation with an ultraviolet irradiation machine (“UM810 (high pressure mercury lamp light source)” (Nitto Seiki Co., Ltd. Manufacture) and the accumulated light intensity of 1000 mJ/cm ² ) to the adhesive sheet to prepare the test piece.

(4) The elastic modulus of the adhesive layer obtained by nanoindentation at a temperature 10°C lower than the foaming initiation temperature of the heat-expandable microspheres The elastic modulus obtained by the nano-indentation method refers to the continuous measurement of the load and indentation depth of the indenter when the indenter is pressed into the sample (such as the adhesive surface) when it is loaded and unloaded. According to the obtained load The elastic modulus obtained from the load-indentation depth curve. The elastic modulus obtained by the nanoindentation method is obtained by using the software (triboscan) with the measuring device, and pressing the diamond-made Berkovich (triangular pyramid) probe vertically to the measuring Numerical processing is performed on the displacement-load hysteresis curve obtained from the cut-out section of the target layer. In this specification, the modulus of elasticity is a nanoindenter (Triboindenter TI-950 manufactured by Hysitron Inc.), through a single indentation method at a specified temperature, at an indentation speed of about 500nm/sec and a pullout speed of about 500nm /sec, the modulus of elasticity measured under the measurement conditions of an indentation depth of about 3000nm.

(5) Chip flying Attach a QFN lead frame (size: 125mm×65mm; the bonding surface to the adhesive sheet is the resin surface) sealed with epoxy resin (manufactured by Hitachi Chemical Co., Ltd., trade name "CEL-9200HF9") to each adhesive sheet On the adhesive layer, install and fix it on a 6-inch dicing ring, and use a slicer to cut it into wafers with a size of 5mm×5mm (implement cutting processing by dicing). The number of wafers that scattered during the dicing was counted. At this time, the cutting blade used was ZH05-SD2000-N1-110-DD manufactured by DISCO Corporation. Set the moving speed of the cutting blade to 70 mm/s, and set the rotational speed of the cutting blade to 50000/s. The ratio (wafer scattering rate) (%) of the number of wafers peeled from the adhesive tape (wafer scattering) during the cutting process was obtained as an evaluation of the cutting processability. In addition, when all the chips were attached to the adhesive tape without peeling off, the chip scattering rate was 0% (that is, the chip scattering rate was 0%). The number of wafers to be diced is A0, the number of wafer scattering is A, and the wafer scattering rate X is obtained from the formula (1). X＝(A/A0)×100 (1) The smaller the ratio of chip peeling (wafer scattering rate), the better the chip scattering prevention property is.

(6) Defective heating and peeling After the aforementioned cutting, heat treatment was performed at the foaming peak temperature for 5 minutes using a programmed temperature regulator (hot air dryer) (manufactured by Isuzu Seisakusho Co., Ltd., "EP-K-300"). After the heat treatment, turn the adhesive tape over in the air so that it is upside down (the chip is on the bottom), and the chip is peeled off from the adhesive tape by natural drop, and the ratio of the chip remaining on the sheet (chip residue) is calculated. (%). In addition, when all the wafers were peeled off and did not remain on the adhesive tape, the remaining wafers were 0%. Therefore, after the heat treatment, the amount of wafer remaining after processing is small (little wafer residue) means that heat peelability is good. Let the number of wafers before peeling be B0 and the number of wafers remaining on the sheet after the heat peeling treatment be B, and the remaining wafers Y can be obtained from Equation (2). Y＝(B/B0)×100 (2)

(7) Chip tilt After cutting in (5) above, heat treatment was performed at the peak foaming temperature for 5 minutes using a programmed temperature controller (hot air dryer) (manufactured by Isuzu Seisakusho Co., Ltd., "EP-K-300"). After the heat treatment, the inclination of the wafer was visually confirmed before the implementation of the above (6), and the ratio of the inclination of the wafer after heat peeling (wafer inclination) (%) was confirmed. Furthermore, when all the wafers are aligned and not tilted, the wafer tilt is 0%. Therefore, less wafers tilted after heat treatment (little wafer tilt) means that the wafers tilted well. Let the number of wafers before peeling be C0, and the number of wafers inclined on the sheet after the heat peeling process be C, and the wafer inclination Z is obtained from the formula (3). Z＝(C/C0)×100 (3)

(8) Poor wafer recovery (number) The total of the number of defectives in (6) above and the number of defectives in (7) above was defined as defective wafer collection.

(9) Particle size distribution peak width and particle size (D50) of heat-expandable microspheres The adhesive sheet was fixed on the holder, and transmission images (1601 sheets for 0° to 360°) were continuously taken by X-ray CT (Zeiss, Xradia 520 Versa, pixel size 0.3 μm/pixel, analysis software ImageJ.). Secondly, reconstruction is carried out on the basis of all the obtained transmission images, tomographic images are made, three-dimensional reconstruction images (TIF stacked images) and cross-sectional images (three-dimensional images) are reconstructed. Based on the obtained three-dimensional reconstruction image (TIF stacked image), the foam was identified, and the cumulative volume particle diameter D50 and peak width were calculated.

[Production Example 1] Production of Polymer 1 Add 30 parts by weight of 2-ethylhexyl acrylate, 70 parts by weight of ethyl acrylate, 5 parts by weight of methyl methacrylate, 5 parts by weight of hydroxyethyl acrylate, and benzyl peroxide as a polymerization initiator in toluene After adding 0.15 parts by weight of acyl, it was heated at 60°C to obtain a toluene solution of an acrylic copolymer (polymer 1).

[Production Example 2] Production of Polymer 2 After adding 100 parts by weight of 2-ethylhexyl acrylate, 25 parts by weight of acrylyl methionine, 18 parts by weight of hydroxyethyl acrylate, and 0.25 parts by weight of benzoyl peroxide as a polymerization initiator in toluene, Heating was performed at 60°C to obtain a toluene solution of an acrylic copolymer. To this was added 12 parts by weight of methacryloxyethyl isocyanate to perform an addition reaction, thereby obtaining a toluene solution of an acrylic copolymer (polymer 2) having a carbon-carbon double bond.

[Production Example 3] Production of Polymer 3 Add 100 parts by weight of butyl acrylate, 5 parts by weight of acrylic acid, and 0.15 parts by weight of benzoyl peroxide as a polymerization initiator to toluene, and heat at 60°C to obtain an acrylic copolymer (polymer 3). Toluene solution.

[Production Example 4] Production of Polymer 4 After adding 100 parts by weight of 2-ethylhexyl acrylate, 5 parts by weight of acrylic acid, and 0.15 parts by weight of benzoyl peroxide as a polymerization initiator to toluene, heat at 60°C to obtain an acrylic copolymer (polymerization Substance 4) in toluene solution.

[Production Example 5] Production of Polymer 5 After adding 100 parts by weight of butyl acrylate, 5 parts by weight of hydroxyethyl acrylate, and 0.15 parts by weight of benzoyl peroxide as a polymerization initiator to toluene, heat at 60°C to obtain an acrylic copolymer (polymer 5) Toluene solution.

[Example 1] (Preparation of elastic layer forming composition) A toluene solution of polymer 1 (100 parts by weight), 1 part by weight of an isocyanate-based crosslinking agent (manufactured by Tosoh Corporation, trade name "CORONATE L"), an active energy ray reactive compound (manufactured by Nippon Synthetic Chemicals Co., Ltd., trade name "Ultraviolet UV1700B") 30 parts by weight, a photopolymerization initiator (manufactured by BASF, trade name "Omnirad 127D") 3 parts by weight, and toluene were mixed to prepare a composition for forming an elastic layer. (Preparation of composition for adhesive layer formation) A toluene solution of polymer 1 (100 parts by weight), 0.5 parts by weight of an isocyanate-based crosslinking agent (manufactured by Tosoh Corporation, trade name "CORONATE L"), an active energy ray reactive compound (manufactured by Nippon Synthetic Chemicals Co., Ltd., trade name "Ultraviolet UV1700B") 30 parts by weight, photopolymerization initiator (manufactured by BASF Corporation, trade name "Omnirad 127D") 3 parts by weight, adhesion imparting agent (manufactured by YASUHARA CHEMICAL CO., LTD., trade name "MightyAce G125") 15 parts by weight, 35 parts by weight of heat-expandable microspheres (manufactured by Akzo Nobel, trade name "092-40DU"), and toluene were mixed to prepare a composition for forming an adhesive layer. (Making of Adhesive Tape) Corona treatment was performed on a PET film (manufactured by Toray, trade name "Lumirror S10", thickness: 25 μm) as a base material, and the above-mentioned composition for forming an elastic layer was applied and dried to form an elastic layer ( Thickness: 50 μm). The above composition for forming an adhesive layer was coated on a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., trade name "MRF38") with a silicone release agent-treated surface, dried, and placed in An adhesive layer (30 μm) was formed on a polyethylene terephthalate film. The above-mentioned adhesive layer formed on the polyethylene terephthalate film was transferred to the above-mentioned elastic layer to obtain an adhesive tape having a base material, an elastic layer, and an adhesive layer in sequence. The obtained adhesive tape was used for said evaluation (1)-(9). The results are shown in the table.

[Examples 2-13, Comparative Examples 1-2] Use the polymers, crosslinking agents, heat-expandable microspheres, active energy ray reactive compounds, and photopolymerization initiators shown in Table 1 according to the formulation amounts shown in Table 1, and use the substrates shown in Table 1, except Otherwise, it carried out similarly to Example 1, and obtained the adhesive sheet. The obtained adhesive sheet was used for the said evaluation. The results are shown in Table 1. In addition, each component used is as follows. (crosslinking agent) ・CORONATE L: Manufactured by Nippon Polyurethane Industry Co., Ltd., brand name "CORONATE L" ・TETRAD C: Manufactured by Mitsubishi Gas, brand name "TETRAD C" (heat-expandable microspheres) ・092-40DU: Made by AkzoNobel, brand name "092-40DU" ・H-750D: Manufactured by KUREHA Corporation, brand name "H-750D" ・EML101: Manufactured by Sekisui Chemical Co., Ltd., brand name "EML101" ・F-50D: Manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., brand name "F-50D" (active energy ray reactive compound) ・UV1700B: Manufactured by Nippon Synthetic Chemicals Co., Ltd., trade name "Ultraviolet UV1700B", molecular weight: 2000, C=C10 pieces/1 molecule ・UV3000B: Manufactured by Nippon Synthetic Chemicals Co., Ltd., trade name "Ultraviolet UV3000B", molecular weight 18000, C=C2 pieces/1 molecule ・UV7605B: Manufactured by Nippon Synthetic Chemicals Co., Ltd., trade name "Ultraviolet UV7605B", molecular weight 1100, C=C6 pieces/1 molecule (photopolymerization initiator) ・Omnirad 127D: Made by BASF Corporation, trade name "Omnirad 127D" ・Omnirad 651: Made by BASF Corporation, brand name "Omnirad 651"

[Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 Comparative example 1 Comparative example 2 adhesive layer base polymer Polymer 1 Polymer 1 Polymer 1 Polymer 1 Polymer 1 Polymer 1 Polymer 1 Polymer 2 Polymer 1 Polymer 3 Polymer 4 Polymer 1 Polymer 1 Polymer 1 Polymer 5 Basic polymer formulation amount (parts by weight) 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 crosslinking agent CORONAIE L deployment amount (parts by weight) 0.5 0.5 0.5 0.5 5 5 3 3 3 5 5 1.5 3 TETRAD C deployment amount (weight part) 0.8 0.8 heat-expandable microspheres 092-40DU deployment amount (weight parts) 35 35 H-750D deployment amount (weight parts) 10 50 30 30 EML101 deployment amount (weight part) 30 30 30 30 30 30 30 F-50D deployment amount (weight parts) 30 30 Thermally expandable microsphere particle size D50(μm) 14 14 17 17 17 17 17 17 17 17 17 17 17 12 12 Particle size distribution peak width (μm) 11 11 10 10 15 15 15 10 10 15 15 15 15 twenty one twenty one Active Energy Ray Reactive Compounds UV1700B 30 50 25 25 13 twenty two 10 13 13 27 13 13 UV3000B 0 11 10 28 11 11 10 11 11 UV7605B 0 12 Photopolymerization initiator Omnirad 127D 3 3 3 3 3 Omnirad 651 3 3 3 3 3 3 3 3 3 Adhesion Imparting Resin MightyAce G125 15 15 15 15 15 15 15 15 15 15 15 5 40 20 elastic layer base polymer Polymer 1 Polymer 1 Polymer 1 Polymer 1 Polymer 1 Polymer 1 Polymer 1 Polymer 2 Polymer 1 Polymer 3 Polymer 4 Polymer 1 Polymer 1 Polymer 1 Polymer 5 Basic polymer formulation amount (parts by weight) 100 100 100 100 100 100 100 100 100 100 100 100 100 crosslinking agent Amount of CORONATE L prepared (parts by weight) 1 1 1 1 1 1 1 1 1 1 1 1 1 Active Energy Ray Reactive Compounds UV1700B 30 50 25 25 13 twenty two 10 13 27 13 13 UV3000B 11 10 28 11 10 11 11 Photopolymerization initiator Omnirad 127D 3 3 3 3 Omnirad 651 3 3 3 3 3 3 3 3 Thickness composition Adhesive layer (μm)/elastic layer (μm) 30/50 30/50 30/50 30/50 30/50 30/50 30/50 30/50 45 30/50 30/50 30/50 30/50 35/15 45 Substrate Corona treated Toray Lumirror S10 #25 Corona-treated Teijin Teonex #38 Corona treated Toray Lumirror S10 #25 With characteristics Adhesive swelling 1.45 1.17 1.13 1.63 1.35 1.11 1.72 1.19 1.98 1.42 1.95 1.2 1.5 3.16 2.26 Initial adhesion (N/20 mm) 7.02 6.50 7.57 5.51 6.67 4.58 7.40 12.67 4.67 4.90 4.25 2.7 8.4 4.31 4.07 Adhesion after UV (N/20 mm) 0.71 0.21 5.47 3.21 4.28 0.68 1.73 0.66 2.12 3.47 1.97 1.2 4.1 4.19 0.74 10°C lower than the foaming start temperature: modulus of elasticity (MPa) 61.1 267.9 17.8 24.5 21.2 69.0 11.3 183.0 12.3 12.8 7.0 25.9 17.4 0.64 2.88 Evaluation Chip scattering (%) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Defective heat peeling (%) 3 3 7 0 0 0 0 0 0 0 0 0 0 5 6 Wafer Tilt (%) 0 0 0 0 0 0 0 0 4 0 3 0 0 25 10 Bad wafer recovery (pieces) 9 9 twenty two 0 0 0 0 0 13 0 9 0 0 97 51

10: Adhesive layer 20: Substrate 30: another adhesive layer 100: Adhesive sheet 200: Adhesive sheet 300: Adhesive sheet

1( a ) to ( c ) are schematic cross-sectional views of an adhesive sheet according to one embodiment of the present invention.

10: Adhesive layer

20: Substrate

30: another adhesive layer

100: Adhesive sheet

200: Adhesive sheet

300: Adhesive sheet

Claims (16)

An adhesive sheet having an adhesive layer comprising heat-expandable microspheres, In the adhesive layer, the expansion property of the adhesive when heated to the peak foaming temperature of the heat-expandable microspheres (thickness of the adhesive layer when heated to the peak foaming temperature of the heat-expandable microspheres/20°C of the adhesive layer Thickness) is 1.1-2. The adhesive sheet according to claim 1, wherein the adhesive layer contains an active energy ray-curable adhesive. The adhesive sheet according to claim 2, wherein the active energy ray-curable adhesive includes a polymer and an oligomer as an active energy ray-reactive compound. The adhesive sheet according to claim 2, wherein the active energy ray-curable adhesive includes an active energy ray-reactive polymer. The adhesive sheet according to any one of claims 2 to 4, wherein the active energy ray-curable adhesive contains a photopolymerization initiator, The photopolymerization initiator is selected from alkylphenone photopolymerization initiators, hydroxyacetophenone photopolymerization initiators, hydroxyketone photopolymerization initiators, aminoacetophenone photopolymerization initiators agent and at least one of the group consisting of benzoyl ketal-based photopolymerization initiators. The adhesive sheet according to any one of claims 2 to 4, wherein the active energy ray-curable adhesive contains an adhesive imparting agent. The adhesive sheet according to claim 5, wherein the active energy ray-curable adhesive contains an adhesive imparting agent. The adhesive sheet according to claim 6, wherein the content ratio of the above-mentioned adhesion-imparting agent is 1 to 100 parts by weight relative to 100 parts by weight of the polymer in the above-mentioned active energy ray-curable adhesive. The adhesive sheet according to claim 7, wherein the content ratio of the above-mentioned adhesion-imparting agent is 1 to 100 parts by weight relative to 100 parts by weight of the polymer in the above-mentioned active energy ray-curable adhesive. The adhesive sheet according to any one of Claims 1 to 4, wherein the elastic modulus of the above-mentioned adhesive layer obtained by nano-indentation method at a temperature 10°C lower than the foaming initiation temperature of the expandable microspheres is: 3.0MPa～400MPa. The adhesive sheet according to any one of claims 1 to 4, wherein the cumulative volume particle diameter D50 of the heat-expandable microspheres is 13 μm to 50 μm. The adhesive sheet according to any one of claims 1 to 4, wherein the peak width of the particle size distribution of the thermally expandable microspheres is 20 μm or less. The adhesive sheet according to any one of claims 1 to 4, wherein the thermally expandable microspheres are contained in a ratio of 5 to 50 parts by weight relative to 100 parts by weight of the polymer in the adhesive. The adhesive sheet according to any one of claims 1 to 4, wherein the initial adhesive force when the adhesive layer of the adhesive sheet is attached to SUS304BA is 0.5 N/20 mm to 25 N/25 mm. The adhesive sheet according to any one of claims 1 to 4, which further includes a substrate, The above-mentioned adhesive layer is configured on at least one side of the substrate. A method of manufacturing an electronic component, comprising: The step of attaching the adhesive sheet as claimed in claim 1 to the device; a step of irradiating the adhesive sheet with ultraviolet rays; and A step of heating the adhesive sheet and peeling off the device from the adhesive sheet.

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