KR20210036295A - Adhesive tape - Google Patents

Abstract

The objective of the present invention is to provide an adhesive tape capable of suppressing an increase in adhesive strength to an object to be deposited even in high temperature conditions and sufficiently reducing the adhesive strength to the object to be deposited by emitting an active energy ray to easily detach the object to be deposited without contaminating the same. An adhesive tape comprises: a sheet-shaped base material enabling an active energy ray to pass therethrough; and an adhesive layer provided on a surface of the sheet-shaped base material. The adhesive layer includes: an acrylic adhesive polymer having a carbon-carbon double bond and a functional group; a photoinitiator; a thermal polymerization initiator; a crosslinking agent reacting with the functional group; and a filler, and the filler has a strength of 20 MPa or more when generating 30% deformation in a minute compression test.

Description

Adhesive tape {ADHESIVE TAPE}

The present invention relates to an adhesive tape, and in particular, to an adhesive tape for temporarily fixing an electronic member, which is used for bonding an electronic member during processing and removing it after high-temperature processing.

In recent years, adhesive tapes are frequently used in manufacturing processes for industrial products. Most of the adhesive tapes for such processes are required to be reliably affixed at the time of use and to be easily peeled off after use. In accordance with such a request, after use, a technique for facilitating peeling of the tape by causing a chemical reaction by applying heat or active energy rays to the pressure-sensitive adhesive of the tape is known. In general, the active energy ray means non-thermal energy such as light and radiation. Further, in general, the reaction mechanism due to active energy rays is distinguished from the reaction mechanism due to heat.

In Patent Document 1, a radiation curable adhesive tape used for fixing a wafer at the time of dicing a semiconductor wafer is described. In this radiation curable adhesive tape, the adhesive layer contains spherical particles of an acrylic resin polymer. Thereby, since the adhesive force is sufficiently reduced by irradiation with radiation, even a large element can be easily picked up without extending the adhesive tape after irradiation with radiation.

Patent Document 2 describes a pressure-sensitive adhesive composition that is used for a film for surface protection such as a display, an optical component or a substrate, and has both adhesiveness and reworkability at a high level. The pressure-sensitive adhesive composition of this film for surface protection contains a hydroxyl group-containing urethane prepolymer, a polyfunctional (meth)acrylate, a thermal radical initiator, a crosslinking agent, and a photo radical initiator. Thereby, the adhesive strength is not excessively increased, and the adhesive force at the time of peeling is reduced by the light irradiation than the adhesive force in the adhesive state, so that both the adhesiveness and the reworkability can be achieved at a high level, and the peeling of the adhesive layer is prevented. The occurrence can also be reduced.

Japanese Unexamined Patent Application Publication No. Hei 9-8109 Japanese Unexamined Patent Application Publication No. 2019-104870

The adherend adhered with the above-described process adhesive tape is often a glass or silicon wafer. In addition, in recent years, micro LED displays are attracting attention as a next-generation display device. However, in the manufacture of such micro LED displays, LED chips are conveyed to the surface of the display substrate to ensure precise and reliable arrangement. In order to do so, a transfer technique using an adhesive tape or an adhesive tape has been studied. Such an electronic member may be processed under a high temperature condition of about 160°C or higher. For example, processing such as a solder reflow process (for example, a reflow temperature of 260°C) or a sealing resin curing process in a batch sealing (for example, a curing temperature of 165°C) may be mentioned.

The radiation curable adhesive tape of Patent Document 1, once placed under high temperature (for example, 160°C or higher) conditions, increases the adhesive strength of the adhesive layer to the adherend, and there is a concern that even if irradiated with radiation, the adhesive strength does not decrease sufficiently. have.

The pressure-sensitive adhesive composition of Patent Document 2 is a urethane-based pressure-sensitive adhesive, and the initial adhesive strength is small. When such a pressure-sensitive adhesive composition is used for temporary fixing of an electronic member, depending on the size and weight of the electronic member as an adherend, there is a possibility that it may be shifted from a predetermined position during processing and transport, or at worst, may be peeled off. In addition, since the pressure-sensitive adhesive composition of Patent Document 2 contains a low molecular weight polyfunctional (meth)acrylate, there is a risk of contaminating the electronic member, or once placed under high temperature (for example, 160°C or higher) conditions, the adherend The adhesive strength of the pressure-sensitive adhesive layer to is increased, and there is a fear that even if light is irradiated, the adhesive strength does not sufficiently decrease.

The present invention is to solve the above problems, and its object is to suppress the increase in adhesion to the adherend even when placed under high temperature conditions, and by irradiating active energy rays, the adhesion to the adherend is sufficiently reduced. It is to provide an adhesive tape that can be easily detached without contaminating an adherend.

The present invention is an adhesive tape having a sheet-like substrate that transmits active energy rays and an adhesive layer provided on the surface of the sheet-like substrate, wherein the adhesive layer is an acrylic adhesive polymer having a carbon-carbon double bond and a functional group, A photopolymerization initiator, a thermal polymerization initiator, a crosslinking agent reacting with the functional group, and a filler are contained, and the filler provides an adhesive tape having a strength of 20 MPa or more at 30% deformation in a micro compression test.

In the above aspect, the thermal polymerization initiator is preferably contained in an amount ranging from 0.1 to 31.0 parts by mass per 100 parts by mass of the acrylic adhesive polymer having a carbon-carbon double bond and a functional group.

In addition, when the average particle diameter of the filler is R (µm) and the thickness of the pressure-sensitive adhesive layer is D (µm), the ratio of R to D (R/D) is preferably in the range of 0.20 to 1.00.

Moreover, it is preferable that the average particle diameter of the said filler is in the range of 2-30 micrometers.

Further, the filler is preferably contained in a range of 1.0 to 62.0 parts by mass with respect to 100 parts by mass of the acrylic adhesive polymer having a carbon-carbon double bond and a functional group.

In addition, it is preferable that the carbon-carbon double bond content of the acrylic adhesive polymer having a carbon-carbon double bond and a functional group is in the range of 0.40 to 1.85 mmol/g.

In addition, it is preferable that the pressure-sensitive adhesive layer contains an oligomer having a carbon-carbon double bond.

In addition, it is preferable that the oligomer having a carbon-carbon double bond has two or more carbon-carbon double bonds, has a carbon-carbon double bond equivalent in the range of 250 to 1,400, and a weight average molecular weight in the range of 1,500 to 4,900. Do.

Further, the oligomer having a carbon-carbon double bond is preferably contained in an amount of up to 120 parts by mass with respect to 100 parts by mass of the acrylic adhesive polymer having a carbon-carbon double bond and a functional group.

Moreover, the said adhesive tape is suitable for use as an adhesive tape for temporary fixing of an electronic member.

Advantageous Effects of Invention According to the present invention, even when placed under high temperature conditions, an increase in adhesion to an adherend is suppressed, and by irradiating an active energy ray, an adhesive tape is provided that sufficiently lowers the adhesion. As a result, electronic components such as elements processed under high temperature conditions using the adhesive tape of the present invention can be easily detached from the adhesive tape after irradiation with active energy rays. That is, after temporarily fixing the adhesive tape, the electronic component processed under high temperature conditions can be finally removed from the adhesive tape without contamination or damage.

The adhesive tape of the present invention has a sheet-shaped substrate and an adhesive layer provided on the surface of the sheet-shaped substrate. The pressure-sensitive adhesive layer may be provided on one side of the sheet-like substrate, or may be provided on both sides.

[Sheet shape description]

The sheet-like substrate is not particularly limited as long as it transmits an active energy ray such as an electron beam or an ultraviolet ray and has a strength to withstand a use environment. Specifically, for example, polyethylene, polypropylene, ethylene-propylene copolymer, polybutene-1, poly-4-methylpentene-1, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid Homopolymers or copolymers of α-olefins such as copolymers and ionomers, vinyl chloride homopolymers or copolymers such as polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene-vinyl acetate copolymer, fluorinated Fluorine-based polymers such as vinyl-ethylene copolymer, vinylidene fluoride-ethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, polyethylene terephthalate, polybutyl And engineering plastics such as len terephthalate, polycarbonate, and polymethyl methacrylate alone or in a mixture thereof. Among these, polyethylene terephthalate is preferable from the viewpoint of versatility and heat resistance. The thickness of such a sheet-like substrate is generally 5 to 200 µm, preferably 10 to 100 µm.

[Adhesive layer]

For the pressure-sensitive adhesive layer, an active energy ray-curable pressure-sensitive adhesive is used. Active energy ray-curable adhesives have adequate adhesive strength to sufficiently fix the adherend in the state, but they are exposed to active energy rays and cause a three-dimensional crosslinking reaction, which greatly increases the storage modulus of the adhesive. At the same time, the glass transition temperature also rises and the volume of the pressure-sensitive adhesive shrinks, so that the adhesion to the adherend is greatly reduced. By doing so, attachment and detachment of the adherend becomes easy, and at that time, it is difficult to generate residual adhesive on the adherend. The active energy ray-curable pressure-sensitive adhesive contains a functional group that exhibits reactivity by irradiation with an active energy ray such as a carbon-carbon double bond.

The active energy ray-curable pressure-sensitive adhesive used in the present invention contains an acrylic pressure-sensitive adhesive polymer, a photoinitiator, a thermal polymerization initiator, a crosslinking agent, and a filler. In general, an active energy ray reactive group (carbon-carbon double bond) is contained in the acrylic adhesive polymer.

The pressure-sensitive adhesive layer is formed on a sheet-like substrate by, for example, a coating method. That is, the active energy ray-curable pressure-sensitive adhesive is diluted with an organic solvent such as toluene or ethyl acetate to obtain a pressure-sensitive adhesive layer coating liquid. Next, the obtained pressure-sensitive adhesive layer coating liquid is applied to the surface of a sheet-like substrate, dried, and cured to form a pressure-sensitive adhesive layer. It is preferable to attach a release-treated sheet-like substrate to the pressure-sensitive adhesive layer. In addition, the pressure-sensitive adhesive layer coating liquid may be applied to the surface of the sheet-like substrate subjected to the release treatment, and dried, and then transferred to the sheet-like substrate and cured to form the pressure-sensitive adhesive layer. The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is generally 5 to 100 µm, preferably 10 to 30 µm, and more preferably 20 to 30 µm.

In addition, for the purpose of enhancing the adhesion between the pressure-sensitive adhesive layer and the sheet-like substrate, corona treatment, plasma treatment, or coating of a primer composition on the surface of the sheet-like substrate is performed, and then the pressure-sensitive adhesive layer coating liquid is applied to the sheet-like substrate. You may apply it to the surface.

(Acrylic adhesive polymer)

The acrylic adhesive polymer bonds the adhesive layer of the adhesive tape to the electronic member during, for example, a period in which the electronic member as an adherend is processed. As the acrylic adhesive polymer, one having a carbon-carbon double bond in the molecule is used. During desorption of an adherend, by irradiating an active energy ray to the pressure-sensitive adhesive layer, the carbon-carbon double bond causes a radical addition reaction, and the polymer chains are highly crosslinked, thereby increasing the storage modulus of the pressure-sensitive adhesive layer and increasing the glass transition temperature. Therefore, the efficiency of deformation at the time of peeling (desorption) of the pressure-sensitive adhesive layer decreases. In addition, since the volume is also contracted, the effect of reducing the adhesive force of the pressure-sensitive adhesive layer is improved.

The method of producing an acrylic adhesive polymer having a carbon-carbon double bond is not particularly limited, but usually, a copolymer is obtained by copolymerizing a (meth)acrylic acid ester and a functional group-containing unsaturated compound, and the functional group of the copolymer is A method of performing an addition reaction of a compound having a functional group capable of addition reaction and a carbon-carbon double bond can be mentioned.

The functional group referred to herein refers to a thermally reactive functional group capable of coexisting with a carbon-carbon double bond. Examples of such a functional group are an active hydrogen group such as a hydroxyl group, a carboxyl group and an amino group, and a functional group that thermally reacts with an active hydrogen group such as a glycidyl group. The active hydrogen group refers to a functional group having an element other than carbon, such as nitrogen, oxygen, or sulfur, and hydrogen directly bonded thereto.

As the addition reaction, for example, a hydroxyl group in the side chain of the copolymer is reacted with an isocyanate compound having a (meth)acryloyloxy group (e.g., 2-methacryloyloxyethyl isocyanate, etc.) A method, a method of reacting a carboxyl group in the side chain of the copolymer with glycidyl (meth)acrylate, a method of reacting a glycidyl group in the side chain of the copolymer with (meth)acrylic acid, and the like. In addition, when performing such a reaction, the acrylic adhesive polymer is crosslinked with a crosslinking agent to be described later, so that functional groups such as a hydroxyl group, a carboxyl group, or a glycidyl group remain in order to achieve a higher molecular weight. In this way, an acrylic adhesive polymer having an active energy ray reactive group (carbon-carbon double bond) and a functional group such as a (meth)acryloyloxy group can be obtained.

In the above addition reaction, it is preferable to use a polymerization inhibitor so that the active energy ray reactivity of the carbon-carbon double bond is maintained. As such a polymerization inhibitor, a quinone-based polymerization inhibitor such as hydroquinone and monomethyl ether is preferable. The amount of the polymerization inhibitor is not particularly limited, but is usually 0.01 to 0.1 parts by mass with respect to the total amount of the base polymer and the radiation-reactive compound.

The acrylic adhesive polymer preferably has a weight average molecular weight of 100,000 to 2 million, more preferably 300,000 to 1.5 million. When the weight average molecular weight of the acrylic pressure-sensitive adhesive polymer is less than 100,000, it is difficult to obtain a solution of a high viscosity pressure-sensitive adhesive composition of thousands to tens of thousands of cP in consideration of coating properties and the like, which is not preferable. In addition, there is a fear that the adhesive strength is lowered, and the retention of the adherend during processing may be insufficient, and the adherend may be contaminated when the adherend is attached or detached. On the other hand, when the weight average molecular weight is more than 2 million, there is no particular problem due to the characteristics of the adhesive tape, but it is difficult to mass-produce an acrylic adhesive polymer. For example, the acrylic adhesive polymer gels during synthesis. In some cases, it is not preferable. Here, the weight average molecular weight means a standard polystyrene conversion value measured by gel permeation chromatography.

The acrylic adhesive polymer has a carbon-carbon double bond content of preferably 0.10 to 2.00 mmol/g, more preferably 0.40 to 1.85 mmol/g. When the content of the carbon-carbon double bond of the acrylic adhesive polymer is less than 0.10 mmol/g, the photoradical crosslinking reaction does not sufficiently occur even when irradiated with active energy rays, and as a result, the adhesive strength cannot be sufficiently reduced, resulting in desorption of the adherend. It becomes difficult. On the other hand, in the case where the carbon-carbon double bond content exceeds 2.00 mmol/g, there is no problem in particular due to the characteristics of the adhesive tape, but it is not practically preferable from the viewpoint of storage stability of the adhesive tape against light. In addition, the carbon-carbon double bond content in the acrylic adhesive polymer can be calculated by measuring the iodine value of the acrylic adhesive polymer.

The main skeleton of the acrylic adhesive polymer is composed of a copolymer containing an alkyl (meth)acrylate monomer, an active hydrogen group-containing monomer, and a glycidyl group-containing monomer. As (meth)acrylic acid alkyl ester monomer, C6-C18 hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl ( Meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylic Rate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, or a monomer having 5 or less carbon atoms, Pentyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, and the like. In addition, as an active hydrogen group-containing monomer, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth) Hydroxy group-containing monomers such as acrylate, carboxyl group-containing monomers such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid, acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride, (meta )Acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, N-methylol (meth)acrylamide, N-methylolpropane (meth)acrylamide, N-methoxymethyl Amide monomers such as (meth)acrylamide and N-butoxymethyl (meth)acrylamide, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate And amino group-containing monomers such as those. Moreover, glycidyl (meth)acrylate etc. are mentioned as a glycidyl group-containing monomer. The content of the thermally reactive functional group capable of coexisting with these carbon-carbon double bonds is not particularly limited, but is preferably in the range of 5 to 50% by mass with respect to the total amount of the copolymerization monomer component.

Specific examples of copolymers obtained by copolymerizing them include a copolymer of 2-ethylhexyl acrylate and acrylic acid, a copolymer of 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate, and 2-ethylhexyl acrylate and methacrylic acid and 2-acrylic acid. Terpolymer of hydroxyethyl, etc. are mentioned, but it is not specifically limited to these.

The acrylic adhesive polymer may contain other copolymerizable monomer components as necessary for the purpose of cohesive strength, heat resistance, and the like. Specific examples of such other copolymerizable monomer components include, for example, cyano group-containing monomers such as (meth)acrylonitrile, olefin-based monomers such as ethylene, propylene, isoprene, butadiene, and isobutylene, styrene, α- Styrene monomers such as methyl styrene and vinyl toluene, vinyl ester monomers such as vinyl acetate and vinyl propionate, vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether, halogen atom-containing monomers such as vinyl chloride and vinylidene chloride, Alkoxy group-containing monomers, such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone , N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, N- And monomers having a nitrogen atom-containing ring such as (meth)acryloylmorpholine. These other copolymerization monomer components may be used alone or in combination of two or more.

(Crosslinkable oligomer)

It is preferable that the pressure-sensitive adhesive layer contains an oligomer having a carbon-carbon double bond. When the pressure-sensitive adhesive layer is irradiated with an active energy ray, this oligomer causes an addition reaction between the oligomers or between the oligomer and the above-described acrylic pressure-sensitive adhesive polymer in the pressure-sensitive adhesive layer, and is highly crosslinked. As a result, compared to the case where the crosslinkable oligomer is not included in the pressure-sensitive adhesive layer, the storage elastic modulus and glass transition temperature of the pressure-sensitive adhesive layer are increased, and the volume shrinks more, so that the adhesion of the pressure-sensitive adhesive layer is reduced when the adherend is detached. The effect of reducing is improved. As a crosslinkable oligomer, a photopolymerizable polyfunctional oligomer is mentioned, for example.

The crosslinkable oligomer preferably has two or more carbon-carbon double bonds. Further, the crosslinkable oligomer has a weight average molecular weight of preferably 1,000 to 5,000, more preferably 1,500 to 4,900. When the weight average molecular weight of the crosslinkable oligomer is less than 1,000, there is a concern that the adherend may be contaminated when the amount of the crosslinkable oligomer is large. In addition, when the amount of carbon-carbon double bonds in the crosslinkable oligomer is small, the adhesion to the adherend increases excessively when placed under high temperature conditions, and the adhesion is not sufficiently reduced even when irradiated with active energy rays during desorption. There is a fear that it will not be. On the other hand, when the weight average molecular weight of the crosslinkable oligomer exceeds 5,000, when the amount of carbon-carbon double bonds in the crosslinkable oligomer is small, the degree of curing and contraction of the pressure-sensitive adhesive layer is small, and the effect of further reducing the adhesive strength is not obtained. There is a fear that it will not be. Here, the weight average molecular weight means a standard polystyrene conversion value measured by gel permeation chromatography.

As for the crosslinkable oligomer, the double bond equivalent is preferably in the range of 150 to 1,500, more preferably in the range of 250 to 1,400, and still more preferably in the range of 250 to 490. If the double bond equivalent of the crosslinkable oligomer is less than 150, it becomes hard due to the effect of increasing the crosslinking density of the pressure-sensitive adhesive layer when irradiated with active energy rays, and the flexural modulus is too high. When is pushed up and removed from the adhesive tape, when the mechanical strength of the adherend is small (specifically, a semiconductor chip or thin-film glass, etc.), there is a fear that the adherend may be broken. In addition, when the content of the crosslinkable oligomer is large, there is a concern that storage stability against light may deteriorate. On the other hand, when the double bond equivalent of the crosslinkable oligomer exceeds 1,500, the degree of curing and contraction of the pressure-sensitive adhesive layer is small, and there is a fear that the effect of further reducing the adhesive strength may not be obtained. Here, the double bond equivalent is defined by the formula: double bond equivalent = molecular weight/number of double bonds in the same molecule. The value of the double bond equivalent defined by the above formula can be calculated from, for example, the amount of double bonds in the sample quantified based on the iodine number measured in accordance with JIS K0070:1992, and the mass or molecular weight of the sample. . When there is a possibility that the sample contains a plurality of components, each component may be fractionated as necessary, and the iodine value of the fractionated component may be measured to obtain a double bond equivalent.

As a preferable crosslinkable oligomer, photopolymerizable polyfunctional oligomers, such as a polyacrylate oligomer, a polyether oligomer, a polyester oligomer, and a polyurethane oligomer, are mentioned. Among these, polyurethane oligomers are preferable from the viewpoint of reduction of exudation of the pressure-sensitive adhesive and adhesion to an adherend under high temperature, and aliphatic polyurethane oligomers are more preferable from the ease of control of reactivity. These photopolymerizable polyfunctional oligomers may be used alone or in combination of two or more.

Examples of polyacrylate oligomers include hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and epoxy. (Meth)acrylate, oligoester (meth)acrylate, etc. are mentioned.

Examples of polyether oligomers include polyethylene glycol, polypropylene glycol, polybutylene glycol, and blockades in which one or both ends thereof are blocked with a blocking agent such as methyl, phenyl, or (meth)acrylate. Can be mentioned.

Examples of the polyester oligomer include ε-caprolactone and a blockade in which one or both ends thereof is blocked with a blocking agent such as methyl, phenyl, or (meth)acrylate.

As a polyurethane oligomer, for example, a macropolyol such as polyether polyol, polyester polyol, polycarbonate polyol, and polybutadiene polyol, and a urethane polyol such as a reaction product of a polyisocyanate monomer, such as hydroxyethyl ( Hydroxy (meth)acrylate monomers such as meth)acrylate, phenylglycidyl ether acrylate, pentaerythritol triacrylate, and glycerin dimethacrylate, and methylene diisocyanate, tolylene diisocyanate, isophorone diisocyanate, etc. Urethane acrylates, such as a polyisocyanate monomer or reaction product with the above-mentioned urethane polyol, etc. are mentioned.

When a crosslinkable oligomer is included in the pressure-sensitive adhesive layer, the blending ratio of the crosslinkable oligomer is preferably 120 parts by mass or less, and more preferably 11 to 100 parts by mass per 100 parts by mass of the acrylic adhesive polymer. When the blending ratio of the crosslinkable oligomer exceeds 120 parts by mass, it is not preferable because the adhesion to the adherend cannot be maintained when processing the adherend under high temperature. In addition, there is a concern that the surface of the adherend after desorption may be contaminated.

(Crosslinking agent)

The pressure-sensitive adhesive layer of the present embodiment further contains a crosslinking agent in order to increase the molecular weight of the acrylic pressure-sensitive adhesive polymer described above. The crosslinking agent is not particularly limited, and a known crosslinking agent having a functional group capable of reacting with a hydroxyl group, a carboxyl group and a glycidyl group, which is a functional group of the acrylic adhesive polymer, can be used. Specifically, for example, polyisocyanate-based cross-linking agent, epoxy-based cross-linking agent, aziridine-based cross-linking agent, melamine resin-based cross-linking agent, urea resin-based cross-linking agent, acid anhydride-based cross-linking agent, polyamine-based cross-linking agent, carboxyl group-containing polymer-based cross-linking agent, and the like. Among these, it is preferable to use a polyisocyanate-based crosslinking agent from the viewpoint of reactivity and versatility. These crosslinking agents may be used alone or in combination of two or more. The blending amount of the crosslinking agent is preferably in the range of 0.01 to 5.00 parts by mass, and more preferably in the range of 0.10 to 3.00 parts by mass, based on 100 parts by mass of the acrylic adhesive polymer. If the blending amount of the crosslinking agent is too large, depending on the type of the acrylic adhesive polymer, there is a fear that the adhesive strength when affixing the adhesive tape to the adherend may decrease, or the uncrosslinked component may contaminate the adherend.

(Thermal polymerization initiator)

The thermal polymerization initiator, in particular, absorbs heat during high-temperature processing after affixing the adherend to the adhesive tape, and reacts to a thermal radical crosslinking reaction in some of the carbon-carbon double bonds of the acrylic adhesive polymer or crosslinkable oligomer. Because of the initiation, crosslinking of the pressure-sensitive adhesive layer proceeds, and the storage modulus and glass transition temperature increase and become harder than the state before taking up heat. As a result, the active energy ray-curable pressure-sensitive adhesive of the present invention containing a thermal polymerization initiator is a phenomenon typically seen in a conventional active energy ray-curable pressure-sensitive adhesive that does not contain a thermal polymerization initiator, that is, the pressure-sensitive adhesive when placed under high temperature conditions. When the layer is softened and wetted by the adherend, the phenomenon that the adhesion to the adherend is excessively increased can be greatly suppressed. In addition, depending on the composition, on the contrary, the adhesive force to the adherend may be roughly reduced before irradiation with active energy rays at the time of desorption. In this state, not all of the carbon-carbon double bonds of the active energy ray-curable pressure-sensitive adhesive are consumed, and a part of the carbon-carbon double bonds remain. Therefore, when the active energy ray is irradiated at the time of desorption, the photo-radical crosslinking reaction of the remaining carbon-carbon double bonds proceeds by the photopolymerization initiator described later, so that the pressure-sensitive adhesive layer is further cured and contracted, and finally the adherend. Can be easily detached from the adhesive tape without contamination or damage. In addition, since the pressure-sensitive adhesive layer has an acrylic pressure-sensitive adhesive polymer as a main component, even if the radical crosslinking reaction proceeds in a part of the pressure-sensitive adhesive layer as described above, the adhesive strength sufficient to hold the adherend during processing under high temperature conditions is I can keep it.

As the thermal polymerization initiator, compounds that generate radically active species by heating are preferable, and examples thereof include peroxides, azo compounds, persulfates, and the like. Among these, peroxides that are easy to use by distinguishing according to the processing temperature of the adherend are preferred.

As a peroxide, specifically, t-butyl hydroperoxide (10 hour half-life temperature 167 degreeC), cumene hydroperoxide (same 158 degreeC), diisopropylbenzene hydroperoxide (same 145 degreeC), and a parameter Tane hydroperoxide (copper 128℃), di-t-butyl peroxide (copper 124℃), di(2-t-butylperoxyisopropyl) benzene (copper 119℃), dicumyl peroxide (copper 117℃) , t-butylperoxybenzoate (104°C copper), dibenzoyl peroxide (74°C), t-butylperoxy-2-ethylhexanoate (72°C), t-hexylperoxy-2- Ethyl hexanoate (70° C.), and the like. These may be used alone or in combination of two or more.

As an azo compound, 1,1-azobis (cyclohexane-1-carbonitrile) (10 hour half-life temperature 88°C), 4,4'-azobis (4-cyanovaleric acid) (68°C), 2 ,2'-azobis (2-methylbutyronitrile) (67°C), dimethyl 2,2'-azobis (2-methylpropionate) (66°C), 2,2'-azobis ( Isobutyronitrile) (65°C), 2,2'-azobisdimethylvaleronitrile (52°C) 1,1'-azobis (1-acetoxy-1-phenylethane) (61°C) , Dimethyl 2,2'-azobisisobutyrate (67°C), azocumene, 2-(tert-butylazo)-2-cyanopropane, 2,2'-azobis (2,4,4 -Trimethylpentane), 2,2'-azobis (2-methylpropane), and other compounds. These may be used alone or in combination of two or more.

Examples of the persulfate include potassium persulfate (10 hour half-life temperature of 71°C), ammonium persulfate (copper 62°C), sodium persulfate (copper 71°C), and the like. These may be used alone or in combination of two or more.

The 10-hour half-life temperature of the thermal polymerization initiator to be used may be appropriately selected according to the processing temperature of the adherend. For example, when the processing temperature is 165 to 200°C, the 10-hour half-life temperature of the thermal polymerization initiator to be used is 60 It is preferable that it is in the range of -125 degreeC. If the 10-hour half-life temperature is too low with respect to the processing temperature, the adhesion to the adherend when placed at the processing temperature decreases too much, and there is a fear that the processing operation may be affected (positional shift or dropout of the adherend). On the other hand, if the 10-hour half-life temperature is too high with respect to the processing temperature, the effect of suppressing the increase in the adhesion to the adherend when placed at the processing temperature is reduced, and the adhesion is not sufficiently reduced even when irradiated with active energy rays during desorption. There is a fear that it will not be.

The amount of the thermal polymerization initiator used in the present invention is preferably 0.1 to 31.0 parts by mass, more preferably 1.0 to 20.0 parts by mass, based on 100 parts by mass of the acrylic adhesive polymer.

When the addition amount of the thermal polymerization initiator is less than 0.1 parts by mass, the curing of the pressure-sensitive adhesive becomes insufficient because the reactivity to heating is insufficient, and as a result, the increase in adhesion when placed under high-temperature conditions cannot be sufficiently suppressed, and later Even if an active energy ray is irradiated, there exists a possibility that it becomes difficult to peel an adherend. On the other hand, when the addition amount of the thermal polymerization initiator exceeds 31.0 parts by mass, the adhesion to the adherend when placed under high temperature conditions is too low, and there is a fear that the processing operation may be affected. In addition, there is a risk of contaminating the adherend.

(Photopolymerization initiator)

The photopolymerization initiator initiates a crosslinking reaction of carbon-carbon double bonds of the acrylic adhesive polymer or crosslinkable oligomer remaining in the adhesive layer after being placed under high temperature conditions by subtracting the irradiation of active energy rays to the adhesive layer during desorption of the adherend. Let it. As a result, the adhesive force to the adherend is reduced by further curing and contracting the pressure-sensitive adhesive layer under irradiation with active energy rays. As the photoinitiator, a compound that generates radically active species by ultraviolet rays or the like is preferable. Specifically, benzoin alkyl ether-based initiators such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; Benzophenone initiators such as benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, and polyvinylbenzophenone; α-hydroxycyclohexylphenylketone, 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, methoxyacetophenone , 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropan-1-one Aromatic ketone initiators such as; Aromatic ketal initiators such as benzyl dimethyl ketal; Thioxanthone, 2-chloro thioxanthone, 2-methyl thioxanthone, 2-ethyl thioxanthone, 2-isopropyl thioxanthone, 2-dodecyl thioxanthone, 2,4-dichloro thioxanthone, 2 Thioxanthone initiators such as ,4-dimethyl thioxanthone, 2,4-diethyl thioxanthone, and 2,4-diisopropyl thioxanthone; Benzyl initiators such as benzyl; Benzoin initiators such as benzoin; Α-ketol compounds such as 2-methyl-2-hydroxypropiophenone; Aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; Photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; Camphorquinone compounds; Halogenated ketone compounds; Acylphosphine oxide-based compounds; And acylphosphonate compounds. These may be used alone or in combination of two or more.

As the photoinitiator, a commercial item can also be used. Specifically, for example, 1-hydroxy-cyclohexyl-phenyl-ketone (trade name Omnirad184, manufactured by IGM Resins BV), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide 1-hydroxy- Cyclohexyl-ketone (brand name Omnirad819, manufactured by IGM Resins BV), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (brand name Omnirad369, manufactured by IGM Resins BV), 2- Benzyl-2-dimethylamino-4'-morpholinobutyrophenone (trade name Omnirad369E, manufactured by IGM Resins BV), 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholine-4 -Yl-phenyl)-butan-1-one (brand name Omnirad379EG, the product made by IGM Resins BV), etc. are mentioned. Among these, it is preferable to use Omnirad369, Omnirad369E, and Omnirad379EG from the viewpoint of heat resistance that radical active species can be sufficiently generated by ultraviolet irradiation or the like even when placed under high temperature conditions.

The amount of the photoinitiator added is preferably 0.1 to 10.0 parts by mass, more preferably 0.5 to 5.0 parts by mass, and still more preferably 1.0 to 2.0 parts by mass, based on 100 parts by mass of the acrylic adhesive polymer.

When the amount of the photoinitiator added is less than 0.1 parts by mass, the curing and contraction of the pressure-sensitive adhesive is insufficient because the photoreactivity to the active energy ray is insufficient, and it may become difficult to peel the adherend even when irradiated with the active energy ray. . On the other hand, when the addition amount exceeds 10.0 parts by mass, the effect is saturated and is not preferable from the viewpoint of economic efficiency.

Further, as a sensitizer for such a photopolymerization initiator, a compound such as dimethylaminoethyl methacrylate and 4-dimethylaminobenzoic acid isoamyl may be added to the pressure-sensitive adhesive.

(filler)

The filler reduces the contact area of the pressure-sensitive adhesive layer with the adherend when the pressure-sensitive adhesive layer is crosslinked by irradiation with active energy rays and cured and contracted. As a result, the effect of reducing the adhesion of the pressure-sensitive adhesive layer to the adherend is further improved.

The filler has a strength of 20 MPa or more, preferably 20 to 70 MPa, and more preferably 29 to 70 MPa, at 30% deformation in a micro-compression test. If the strength at the time of 30% deformation of the filler is less than 20 MPa, the effect of reducing the contact area of the pressure-sensitive adhesive layer with the adherend may become insufficient. As a result, after being placed under high-temperature conditions, even if the active energy ray is irradiated, the adhesive strength does not sufficiently decrease, and there is a fear that it becomes difficult to peel the adherend.

In the present invention, the strength at the time of 30% deformation in the micro-compression test of the filler is a value measured using a micro-compression tester "MCT-510" (product name) manufactured by Shimadzu Corporation. Specifically, it is measured by the following method. First, the filler to be used is dispersed in ethanol, and then the dispersion of the filler is applied and dried on a sample stand (material: SKS flat plate) of a micro-compression tester to prepare a sample for measurement. Next, one independent filler is picked out with an optical microscope of MCT-510, and the particle diameter (diameter) (dn) (unit: mm) of the picked filler is measured with a particle size measuring cursor of MCT-510. Next, by dropping a pressure indenter (a diamond flat indenter with a diameter of 50 μm) at the apex of the picked filler at a constant load speed (9.6841 mN/sec), a load is gradually applied to the filler up to a maximum load of 490 mN, and then measured first. From the load (Pn) (unit: N) at the time when the particle diameter (diameter) of one filler is displaced by 30%, according to the following equation (1), based on JIS R 1639-5:2007, compressive strength (Fn) Calculate (unit: MPa). Five measurements are made for each filler, and the average value of the three data excluding the data of the maximum and minimum values is taken as the strength at the time of 30% deformation in the micro compression test. In addition, the measurement is carried out in an environment of 23±5°C and 50±10%RH. In the present invention, the measurement was performed in an environment of 23°C and 50%RH.

Fn=2.48×Pn/(π·dn ² ) Equation (1)

Since the filler has a predetermined strength (hardness), the pressure-sensitive adhesive layer is crosslinked by irradiation of active energy rays, and when cured and contracted, the contact area of the pressure-sensitive adhesive layer with respect to the adherend is reduced. It further promotes the effect of reducing the adhesion to the body.

When the size of the filler is related to the thickness of the pressure-sensitive adhesive layer, when the average particle diameter of the filler is R (µm) and the thickness of the pressure-sensitive adhesive layer is D (µm), the ratio of R to D (R/ D) is preferably in the range of 0.20 to 1.00, more preferably 0.40 to 0.80, and still more preferably 0.50 to 0.80. When the ratio of R and D (R/D) is less than 0.20, the action of reducing the contact area of the pressure-sensitive adhesive layer with respect to the adherend may become insufficient. As a result, after being placed under high-temperature conditions, even if the active energy ray is irradiated, the adhesive strength does not sufficiently decrease, and there is a fear that it becomes difficult to peel the adherend. On the other hand, when the ratio (R/D) of R and D exceeds 1.00, there is a concern that the adhesion between the pressure-sensitive adhesive layer and the sheet-like substrate may deteriorate. In addition, there is a fear that the initial adhesive strength to the adherend before irradiation with the active energy ray decreases, the adherend cannot be sufficiently held, and affects the processing operation (positional shift or dropout of the adherend).

When the thickness of the pressure-sensitive adhesive layer described above is, for example, in a preferred range of 10 to 30 µm, the average particle diameter of the filler is preferably 2 to 30 µm, more preferably 4 to 24 µm, more preferably 5 It is in the range of -24 µm. When the average particle diameter of the filler is in the above range, the effect of reducing the contact area of the pressure-sensitive adhesive layer with respect to the adherend can be more remarkably expressed. In addition, the average particle diameter in the present invention means that the filler is not dissolved or swelled using a laser scattering particle size distribution meter (e.g., a particle size distribution measuring device manufactured by Horiba Manufacturing Co., Ltd. ``model number LA-920''). When a filler and a dispersant are added to the medium, and the integral volume is calculated from particles having a small particle size distribution measured after ultrasonic dispersion, the value of the 50% diameter in the integrated fraction based on the volume (D _50% ), the median diameter. it means.

The filler is contained in a range of preferably 1.0 to 62.0 parts by mass, more preferably 1.5 to 50.0 parts by mass, and still more preferably 2.0 to 10.0 parts by mass, based on 100 parts by mass of the acrylic adhesive polymer. When the content of the filler is less than 1.0 part by mass, the action of reducing the contact area of the pressure-sensitive adhesive layer with respect to the adherend may become insufficient. As a result, there is a fear that it becomes difficult to peel the adherend even if it is irradiated with an active energy ray after being placed under high temperature conditions. On the other hand, when the content of the filler exceeds 62.0 parts by mass, there is a concern that the adhesion between the pressure-sensitive adhesive layer and the sheet-like substrate may deteriorate. In addition, there is a fear that the initial adhesive strength to the adherend before irradiation with the active energy ray decreases, the adherend cannot be sufficiently held, and affects the processing operation (positional shift or dropout of the adherend). When the filler is contained in this range, the effect of reducing the contact area of the pressure-sensitive adhesive layer to the adherend can be remarkably expressed.

In some embodiments, as the filler, crosslinked particles of acrylic polymers widely used in various applications such as toner component use, additive use for paints, optical material use, cosmetic use, molding resin use, etc. are used. I can. As a method for producing crosslinked particles of an acrylic polymer, a method of preparing a polymer in a homogeneous reaction system, pulverizing and classifying the polymer, and finely dispersing a monomer in a reaction solvent that does not substantially dissolve the monomer such as an aqueous medium, A method for producing an acrylic polymer by polymerizing an acrylic monomer finely dispersed in a micro oil droplet shape, and adding fine acrylic polymer particles (seed particles) of the same type when polymerizing the acrylic monomer in this heterogeneous system Then, a method of reacting an acrylic monomer on the acrylic polymer fine particles such that the acrylic polymer fine particles are impregnated with an acrylic monomer so that the acrylic polymer fine particles grow.

Specifically, for example, by using an acrylic monomer such as methyl methacrylate, methyl acrylate, butyl acrylate, butyl methacrylate alone or in combination in the presence of a crosslinking agent, polymerization into a three-dimensional structure It is prepared by synthesizing a polymer of one acrylic resin, subjected to dehydration treatment, and then jet pulverization. As the crosslinking agent, polyfunctional vinyl compounds such as divinylbenzene, ethylene glycol dimethacrylate, and trimethylolpropane triacrylate are used. The acrylic resin polymer thus obtained is spherical particles having a weight average molecular weight of about 20,000 to 1 million. In order to more remarkably exhibit the effect of reducing the contact area of the pressure-sensitive adhesive layer with respect to the adherend, the aspect ratio of the filler is preferably about 0.8 to 1.2.

The filler is not particularly limited in material, shape, crosslinking, non-crosslinking, etc., as long as the strength at 30% deformation in the micro-compression test is 20 MPa or more. As a filler other than the crosslinked particles of the acrylic polymer described above, for example , Crosslinked methyl (meth)acrylate-styrene copolymer particles, crosslinked polystyrene particles, crosslinked butyl (meth)acrylate-styrene copolymer particles, resin particles such as silicone resin particles, or inorganic particles such as alumina and silica You can use it. In addition, the active energy ray-curable pressure-sensitive adhesive used in the present invention, in the range of not impairing the effect of the present invention, in addition to the filler having a strength of 20 MPa or more at 30% deformation in the micro-compression test, in the micro-compression test. It may contain a small amount of a filler having a strength of less than 20 MPa at the time of 30% deformation.

[Example]

The present invention will be described in more detail by the following examples, but the present invention is not limited thereto.

1. Preparation of adhesive tape

(Example 1)

<Sheet shape description>

As a sheet-like substrate, a PET film (trade name: E5100) made by Toyobo and having a thickness of 100 µm was prepared. In addition, on the surface of the sheet-like substrate on the side where the pressure-sensitive adhesive layer is formed, corona treatment was performed in order to increase the adhesion.

<Peeling film>

As a release film, a 50 µm-thick release film (trade name: HY-S06) manufactured by Higashiyama Film Co., Ltd. was prepared.

<Production of acrylic adhesive polymer A>

As a copolymerization monomer component, 2-ethylhexyl acrylate (2-EHA), 2-hydroxyethyl acrylate (2-HEA), and methacrylic acid (MAA) were prepared. These copolymerization monomer components are mixed so as to have a copolymerization ratio of 2-EHA/2-HEA/MAA=73% by mass/25% by mass/2% by mass, and the base polymer is prepared by solution radical polymerization using ethyl acetate as a solvent. Synthesized. Next, 15 parts by mass of 2-isocyanate ethyl methacrylate (MOI) having an isocyanate group and an active energy ray-reactive carbon-carbon double bond as an active energy ray-reactive compound are blended with respect to 100 parts by mass of the solid content of this base polymer, and 2 It reacted with a part of the hydroxyl group of -HEA, and the acrylic adhesive polymer A (solid content concentration: 30 mass %) which has a carbon-carbon double bond in a side chain was synthesize|combined. In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor. It was 800,000 when the weight average molecular weight of the synthesized acrylic adhesive polymer A was measured by gel permeation chromatography (GPC, solvent: tetrahydrofuran). In addition, the carbon-carbon double bond content was 0.84 mmol/g.

<Preparation of an adhesive solution (adhesive composition)>

With respect to 333.3 parts by mass of the solution of acrylic adhesive polymer A prepared above (100 parts by mass in terms of solid content), Soken Chemical Co., Ltd. crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 μm, crosslinking degree: standard , Strength at 30% deformation in the micro-compression test: 55 MPa) in a ratio of 3.0 parts by mass, stirred uniformly, and then diacyl peroxide-based peroxide A (trade name: Niper BMT) manufactured by Nichis as a thermal polymerization initiator. -K40, solid content concentration: 40% by mass, 10 hours half-life temperature: 73.1°C) 9.0 parts by mass (3.6 parts by mass in terms of solid content), α-aminoalkylphenone photopolymerization initiator A (trade name:) manufactured by IGM Resins BV as a photoinitiator (trade name: 1.5 parts by mass of OmniRad 369) and 0.53 parts by mass (0.4 parts by mass in terms of solid content) were blended with Tosoh Corporation's isocyanate-based cross-linking agent A (trade name: Coronate L, solid content concentration: 75% by mass) as a crosslinking agent, It was diluted with ethyl acetate and stirred to prepare a pressure-sensitive adhesive solution having a solid content concentration of 30% by mass.

<Production of adhesive tape>

Then, the pressure-sensitive adhesive solution prepared above was applied onto the corona-treated surface of the above-described PET film so that the dry thickness of the pressure-sensitive adhesive layer was 30 μm, dried, the release film was attached to the pressure-sensitive adhesive layer, and wound to produce an adhesive tape. did.

After the pressure-sensitive adhesive layer was formed on the sheet-like substrate, it was aged for 120 hours in an environment at 40°C, and the alkyl-based pressure-sensitive polymer was crosslinked with a crosslinking agent to heat-cure, thereby preparing a pressure-sensitive adhesive tape for evaluation.

(Example 2)

Except having changed the preparation of the adhesive solution to the following, it carried out similarly to Example 1, and produced the adhesive tape.

<Preparation of an adhesive solution (adhesive composition)>

With respect to 333.3 parts by mass of the solution of the acrylic adhesive polymer A prepared above (100 parts by mass in terms of solid content), the urethane acrylate oligomer A (trade name: Atresin UN-3320HA, weight average molecular weight: 1,500, functional group) Number: 6, double bond equivalent: 250) 42.7 parts by mass, Soken Chemical Co., Ltd. crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 µm, crosslinking degree: standard, 30 in the micro-compression test % Strength at deformation: 55 MPa) in a ratio of 3.0 parts by mass, stirred uniformly, and then diacyl peroxide-based peroxide A (trade name: Niper BMT-K40, solid content concentration: 40 mass) manufactured by Nichis as a thermal polymerization initiator %, 10 hour half-life temperature:73.1°C) 3.0 parts by mass (1.2 parts by mass in terms of solid content), and 1.5 parts by mass of α-aminoalkylphenone photopolymerization initiator A (trade name: Omnirad 369) manufactured by IGM Resins BV as a photoinitiator , As a crosslinking agent, an isocyanate crosslinking agent A (brand name: coronate L, solid content concentration: 75% by mass) manufactured by Tosoh Corporation was blended in a ratio of 0.53 parts by mass (0.4 parts by mass in terms of solid content), diluted with ethyl acetate, and stirred, A pressure-sensitive adhesive solution having a solid content concentration of 30% by mass was prepared.

(Example 3)

A pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the following acrylic pressure-sensitive adhesive polymer B was used as the acrylic pressure-sensitive adhesive polymer, and the preparation of the pressure-sensitive adhesive solution was changed to the following.

<Production of acrylic adhesive polymer B>

As a copolymerization monomer component, 2-ethylhexyl acrylate (2-EHA) and 2-hydroxyethyl acrylate (2-HEA) were prepared. These copolymerized monomer components were mixed so as to have a copolymerization ratio of 2-EHA/2-HEA=75% by mass/25% by mass, and a base polymer was synthesized by solution radical polymerization using ethyl acetate as a solvent. Next, 15 parts by mass of 2-isocyanate ethyl methacrylate (MOI) having an isocyanate group and an active energy ray-reactive carbon-carbon double bond as an active energy ray-reactive compound are blended with respect to 100 parts by mass of the solid content of this base polymer, and 2 It reacted with a part of the hydroxyl group of -HEA, and the acrylic adhesive polymer B (solid content concentration: 30 mass %) which has a carbon-carbon double bond in a side chain was synthesize|combined. In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor. It was 800,000 when the weight average molecular weight of the synthesized acrylic adhesive polymer B was measured by gel permeation chromatography (GPC, solvent: tetrahydrofuran). In addition, the carbon-carbon double bond content was 0.84 mmol/g.

<Preparation of an adhesive solution (adhesive composition)>

With respect to 333.3 parts by mass of the solution of the acrylic adhesive polymer B prepared above (100 parts by mass in terms of solid content), the crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 µm, crosslinking degree: standard) , Strength at 30% deformation in the micro-compression test: 55 MPa) in a ratio of 3.0 parts by mass, stirred uniformly, and then diacyl peroxide-based peroxide A (trade name: Niper BMT) manufactured by Nichis as a thermal polymerization initiator. -K40, solid content concentration: 40% by mass, 10 hour half-life temperature: 73.1°C) 3.0 parts by mass (1.2 parts by mass in terms of solid content), α-aminoalkylphenone photopolymerization initiator A (brand name: 1.5 parts by mass of OmniRad 369) and 0.53 parts by mass (0.4 parts by mass in terms of solid content) were blended with Tosoh Corporation's isocyanate-based cross-linking agent A (trade name: Coronate L, solid content concentration: 75% by mass) as a crosslinking agent, It was diluted with ethyl acetate and stirred to prepare a pressure-sensitive adhesive solution having a solid content concentration of 30% by mass.

(Example 4)

Except having changed the preparation of the adhesive solution to the following, it carried out similarly to Example 3, and produced the adhesive tape.

<Preparation of an adhesive solution (adhesive composition)>

With respect to 333.3 parts by mass of the solution of the acrylic adhesive polymer B prepared above (100 parts by mass in terms of solid content), the urethane acrylate oligomer A (trade name: Atresin UN-3320HA, weight average molecular weight: 1,500, functional group) Number: 6, double bond equivalent: 250) 11.2 parts by mass, Soken Chemical Co., Ltd. crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 µm, crosslinking degree: standard, 30 in the micro-compression test % Strength at deformation: 55 MPa) in a ratio of 3.0 parts by mass, stirred uniformly, and then diacyl peroxide-based peroxide A (trade name: Niper BMT-K40, solid content concentration: 40 mass) manufactured by Nichis as a thermal polymerization initiator %, 10 hour half-life temperature:73.1°C) 3.0 parts by mass (1.2 parts by mass in terms of solid content), and 1.5 parts by mass of α-aminoalkylphenone photopolymerization initiator A (trade name: Omnirad 369) manufactured by IGM Resins BV as a photoinitiator , As a crosslinking agent, an isocyanate crosslinking agent A (brand name: coronate L, solid content concentration: 75% by mass) manufactured by Tosoh Corporation was blended in a ratio of 0.53 parts by mass (0.4 parts by mass in terms of solid content), diluted with ethyl acetate, and stirred, A pressure-sensitive adhesive solution having a solid content concentration of 30% by mass was prepared.

(Example 5)

Example 4 except that the blending amount of the urethane acrylate oligomer A (trade name: Atresin UN-3320HA, weight average molecular weight: 1500, number of functional groups: 6, double bond equivalent: 250) manufactured by Negami Industries was changed to 42.7 parts by mass. In the same manner as, an adhesive tape was produced.

(Example 6)

The mixing amount of the urethane acrylate oligomer A (trade name: Atresin UN-3320HA, weight average molecular weight: 1500, functional group number: 6, double bond equivalent: 250) manufactured by Negami Industries was changed to 100.0 parts by mass, and manufactured by Soken Chemical Co., Ltd. Except for changing the blending amount of crosslinked acrylic filler A (brand name: Chemisnow MX-2000, average particle diameter: 20 µm, degree of crosslinking: standard, strength at 30% deformation in micro-compression test: 55 MPa) to 1.5 parts by mass It carried out similarly to Example 4, and produced the adhesive tape.

(Example 7)

Example 6 except that the blending amount of the urethane acrylate oligomer A (trade name: Atresin UN-3320HA, weight average molecular weight: 1500, number of functional groups: 6, double bond equivalent: 250) manufactured by Negami Industries was changed to 120.0 parts by mass. In the same manner as, an adhesive tape was produced.

(Example 8)

An adhesive tape was produced in the same manner as in Example 1 except that the following acrylic adhesive polymer C was used as the acrylic adhesive polymer.

<Production of acrylic adhesive polymer C>

As a copolymerization monomer component, 2-ethylhexyl acrylate (2-EHA) and 2-hydroxyethyl acrylate (2-HEA) were prepared. These copolymerized monomer components were mixed so as to have a copolymerization ratio of 2-EHA/2-HEA=75% by mass/25% by mass, and a base polymer was synthesized by solution radical polymerization using ethyl acetate as a solvent. Next, with respect to 100 parts by mass of the solid content of the base polymer, 10 parts by mass of 2-isocyanate ethyl methacrylate (MOI) having an isocyanate group and an active energy ray-reactive carbon-carbon double bond as an active energy ray-reactive compound are blended, and 2 It reacted with a part of the hydroxyl group of -HEA, and the acrylic adhesive polymer C (solid content concentration: 30 mass %) which has a carbon-carbon double bond in a side chain was synthesize|combined. In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor. When the weight average molecular weight of the synthesized acrylic adhesive polymer C was measured by gel permeation chromatography (GPC, solvent: tetrahydrofuran), it was 800,000. In addition, the carbon-carbon double bond content was 0.58 mmol/g.

(Example 9)

Except having changed the preparation of the adhesive solution to the following, it carried out similarly to Example 8, and produced the adhesive tape.

<Preparation of an adhesive solution (adhesive composition)>

Urethane acrylate oligomer A (trade name: Atresin UN-3320HA, weight average molecular weight: 1,500, functional group) manufactured by Negami Industries, with respect to 333.3 parts by mass of the solution of acrylic adhesive polymer C prepared above (100 parts by mass in terms of solid content). Number: 6, double bond equivalent: 250) 42.7 parts by mass, Soken Chemical Co., Ltd. crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 µm, crosslinking degree: standard, 30 in the micro-compression test % Strength at deformation: 55 MPa) in a ratio of 3.0 parts by mass, stirred uniformly, and then diacyl peroxide-based peroxide A (trade name: Niper BMT-K40, solid content concentration: 40 mass) manufactured by Nichis as a thermal polymerization initiator %, 10 hour half-life temperature:73.1°C) 3.0 parts by mass (1.2 parts by mass in terms of solid content), and 1.5 parts by mass of α-aminoalkylphenone photopolymerization initiator A (trade name: Omnirad 369) manufactured by IGM Resins BV as a photoinitiator , As a crosslinking agent, an isocyanate crosslinking agent A (brand name: coronate L, solid content concentration: 75% by mass) manufactured by Tosoh Corporation was blended in a ratio of 0.53 parts by mass (0.4 parts by mass in terms of solid content), diluted with ethyl acetate, and stirred, A pressure-sensitive adhesive solution having a solid content concentration of 30% by mass was prepared.

(Example 10)

An adhesive tape was produced in the same manner as in Example 1 except that the following acrylic adhesive polymer D was used as the acrylic adhesive polymer, and the preparation of the adhesive solution was changed to the following.

<Production of acrylic adhesive polymer D>

As a copolymerization monomer component, 2-ethylhexyl acrylate (2-EHA) and 2-hydroxyethyl acrylate (2-HEA) were prepared. These copolymerized monomer components were mixed so as to have a copolymerization ratio of 2-EHA/2-HEA=55% by mass/45% by mass, and a base polymer was synthesized by solution radical polymerization using ethyl acetate as a solvent. Next, with respect to 100 parts by mass of the solid content of the base polymer, 35 parts by mass of 2-isocyanate ethylacrylate (AOI) having an isocyanate group and an active energy ray-reactive carbon-carbon double bond as an active energy ray-reactive compound are blended, and 2- It reacted with a part of the hydroxyl group of HEA, and the acrylic adhesive polymer D (solid content concentration: 30 mass %) which has a carbon-carbon double bond in a side chain was synthesize|combined. In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor. It was 700,000 when the weight average molecular weight of the synthesized acrylic adhesive polymer D was measured by gel permeation chromatography (GPC, solvent: tetrahydrofuran). In addition, the carbon-carbon double bond content was 1.83 mmol/g.

<Preparation of adhesive solution>

With respect to 333.3 parts by mass of the solution of the acrylic adhesive polymer D prepared above (100 parts by mass in terms of solid content), Soken Chemical Co., Ltd. crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 μm, crosslinking degree: standard , Strength at 30% deformation in the micro-compression test: 55 MPa) in a ratio of 3.0 parts by mass, stirred uniformly, and then diacyl peroxide-based peroxide A (trade name: Niper BMT) manufactured by Nichis as a thermal polymerization initiator. -K40, solid content concentration: 40% by mass, 10 hour half-life temperature: 73.1°C) 0.3 parts by mass (0.12 parts by mass in terms of solid content), α-aminoalkylphenone photopolymerization initiator A (trade name: 0.12 parts by mass) manufactured by IGM Resins BV as a photoinitiator (trade name: 1.5 parts by mass of OmniRad 369) and 0.53 parts by mass (0.4 parts by mass in terms of solid content) were blended with Tosoh Corporation's isocyanate-based cross-linking agent A (trade name: Coronate L, solid content concentration: 75% by mass) as a crosslinking agent, It was diluted with ethyl acetate and stirred to prepare a pressure-sensitive adhesive solution having a solid content concentration of 30% by mass.

(Example 11)

Except having changed preparation of the adhesive solution to the following, it carried out similarly to Example 10, and produced the adhesive tape.

<Preparation of an adhesive solution (adhesive composition)>

Urethane acrylate oligomer A (trade name: Atresin UN-3320HA, weight average molecular weight: 1,500, functional group) manufactured by Negami Industries Co., Ltd. with respect to 333.3 parts by mass of the solution of acrylic adhesive polymer D prepared above (100 parts by mass in terms of solid content) Number: 6, double bond equivalent: 250) 42.7 parts by mass, Soken Chemical Co., Ltd. crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 µm, crosslinking degree: standard, 30 in the micro-compression test % Strength at deformation: 55 MPa) in a ratio of 3.0 parts by mass, stirred uniformly, and then diacyl peroxide-based peroxide A (trade name: Niper BMT-K40, solid content concentration: 40 mass) manufactured by Nichis as a thermal polymerization initiator %, 10 hour half-life temperature:73.1°C) 3.0 parts by mass (1.2 parts by mass in terms of solid content), and 1.5 parts by mass of α-aminoalkylphenone photopolymerization initiator A (trade name: Omnirad 369) manufactured by IGM Resins BV as a photoinitiator , As a crosslinking agent, an isocyanate crosslinking agent A (brand name: coronate L, solid content concentration: 75% by mass) manufactured by Tosoh Corporation was blended in a ratio of 0.53 parts by mass (0.4 parts by mass in terms of solid content), diluted with ethyl acetate, and stirred, A pressure-sensitive adhesive solution having a solid content concentration of 30% by mass was prepared.

(Example 12)

A pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the following acrylic pressure-sensitive adhesive polymer E was used as the acrylic pressure-sensitive adhesive polymer, and the preparation of the pressure-sensitive adhesive solution was changed to the following.

<Production of acrylic adhesive polymer E>

As a copolymerization monomer component, 2-ethylhexyl acrylate (2-EHA) and 2-hydroxyethyl acrylate (2-HEA) were prepared. These copolymerized monomer components were mixed so as to have a copolymerization ratio of 2-EHA/2-HEA = 78% by mass/22% by mass, and a base polymer was synthesized by solution radical polymerization using ethyl acetate as a solvent. Next, with respect to 100 parts by mass of the solid content of the base polymer, 7 parts by mass of 2-isocyanate ethyl methacrylate (MOI) having an isocyanate group and an active energy ray-reactive carbon-carbon double bond as an active energy ray-reactive compound were added, and 2 It reacted with a part of the hydroxyl group of -HEA, and the acrylic adhesive polymer E (solid content concentration: 30 mass %) which has a carbon-carbon double bond in a side chain was synthesize|combined. In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor. It was 800,000 when the weight average molecular weight of the synthesized acrylic adhesive polymer E was measured by gel permeation chromatography (GPC, solvent: tetrahydrofuran). In addition, the carbon-carbon double bond content was 0.41 mmol/g.

<Preparation of adhesive solution>

With respect to 333.3 parts by mass of the solution of the acrylic adhesive polymer E prepared above (100 parts by mass in terms of solid content), the urethane acrylate oligomer A (trade name: Atresin UN-3320HA, weight average molecular weight: 1,500, functional group) Number: 6, double bond equivalent: 250) 50.0 parts by mass, Soken Chemical Co., Ltd. crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 µm, crosslinking degree: standard, 30 in the micro-compression test % Strength at deformation: 55 MPa) in a ratio of 3.0 parts by mass, stirred uniformly, and then diacyl peroxide-based peroxide A (trade name: Niper BMT-K40, solid content concentration: 40 mass) manufactured by Nichis as a thermal polymerization initiator %, 10 hour half-life temperature:73.1°C) 3.0 parts by mass (1.2 parts by mass in terms of solid content), and 1.5 parts by mass of α-aminoalkylphenone photopolymerization initiator A (trade name: Omnirad 369) manufactured by IGM Resins BV as a photoinitiator , As a crosslinking agent, an isocyanate crosslinking agent A (brand name: coronate L, solid content concentration: 75% by mass) manufactured by Tosoh Corporation was blended in a ratio of 0.53 parts by mass (0.4 parts by mass in terms of solid content), diluted with ethyl acetate, and stirred, A pressure-sensitive adhesive solution having a solid content concentration of 30% by mass was prepared.

(Example 13)

An adhesive tape was produced in the same manner as in Example 5, except that 1.5 parts by mass of a hindered phenolic antioxidant A (trade name: Irganox 1010) manufactured by BASF Japan as an antioxidant was further added to the pressure-sensitive adhesive solution.

(Example 14)

Changed the blending amount of the Soken Chemical Co., Ltd. crosslinked acrylic filler A (brand name: Chemisnow MX-2000, average particle diameter: 20 µm, degree of crosslinking: standard, strength at 30% deformation in micro-compression test: 55 MPa) to 1.5 parts by mass Except having done, it carried out similarly to Example 5, and produced the adhesive tape.

(Example 15)

Changed the blending amount of the Soken Chemical Co., Ltd. crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 µm, degree of crosslinking: standard, strength at 30% deformation in micro-compression test: 55 MPa) to 50.0 parts by mass Except having done, it carried out similarly to Example 5, and produced the adhesive tape.

(Example 16)

Changed the blending amount of the Soken Chemical Co., Ltd. crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 µm, degree of crosslinking: standard, strength at 30% deformation in micro-compression test: 55 MPa) to 61.2 parts by mass Except having done, it carried out similarly to Example 5, and produced the adhesive tape.

(Example 17)

Soken Chemical Co., Ltd. crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 µm, crosslinking degree: standard, strength at 30% deformation in micro-compression test: 55 MPa) is an acrylic filler made by Soken Chemical Co., Ltd. B (brand name: MX-1000, average particle diameter: 10 µm, degree of crosslinking: standard, strength at 30% deformation in micro-compression test: 56 MPa), except for changing to the same procedure as in Example 5, to prepare an adhesive tape. .

(Example 18)

Soken Chemical Co., Ltd. crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 µm, crosslinking degree: standard, strength at 30% deformation in micro-compression test: 55 MPa) is an acrylic filler made by Soken Chemical Co., Ltd. C (brand name: Chemisnow MX-500, average particle diameter: 5 μm, crosslinking degree: standard, strength at 30% deformation in micro-compression test: 56 MPa), and the thickness of the pressure-sensitive adhesive layer was changed to 25 μm. Except that, it carried out similarly to Example 5, and produced the adhesive tape.

(Example 19)

A pressure-sensitive adhesive tape was produced in the same manner as in Example 5 except that the dry thickness of the pressure-sensitive adhesive layer was changed to 25 µm.

(Example 20)

Nichiyu Corporation's diacyl peroxide-based peroxide A (trade name: Niper BMT-K40, solid content concentration: 40 mass%, 10 hour half-life temperature: 73.1°C) changed to 0.3 parts by mass (0.12 parts by mass in terms of solid content) Except, it carried out similarly to Example 5, and produced the adhesive tape.

(Example 21)

Diacyl peroxide-based peroxide A (trade name: Niper BMT-K40, solid content concentration: 40% by mass, 10 hour half-life temperature: 73.1°C) manufactured by Nichiyu Corporation was changed to 50.0 parts by mass (20.0 parts by mass in terms of solid content) Except, it carried out similarly to Example 5, and produced the adhesive tape.

(Example 22)

Nichiyu Co., Ltd. diacyl peroxide-based peroxide A (brand name: Niper BMT-K40, solid content concentration: 40% by mass, 10 hour half-life temperature: 73.1°C) changed to 75.8 parts by mass (30.3 parts by mass in terms of solid content) Except it, it carried out similarly to Example 4, and produced the adhesive tape.

(Example 23)

Nichiyu Co., Ltd. diacyl peroxide-based peroxide A (brand name: Niper BMT-K40, solid content concentration: 40 mass%, 10 hour half-life temperature: 73.1 °C) Nichiyu Co., Ltd. peroxy ester-based peroxide B (brand name: Perbutyl O , Solid content concentration: 100% by mass, 10 hour half-life temperature: 72.1°C), except that the blending amount was set to 1.2 parts by mass, to prepare an adhesive tape in the same manner as in Example 5.

(Example 24)

Dialkyl peroxide-based peroxide A (trade name: Niper BMT-K40, solid content concentration: 40% by mass, 10 hour half-life temperature: 73.1°C) manufactured by Nichiyu Co., Ltd. D, solid content concentration: 100% by mass, 10 hour half-life temperature: 123.7°C), except that the blending amount was set to 1.2 parts by mass, was carried out in the same manner as in Example 5 to prepare an adhesive tape.

(Example 25)

Nichiyu Co., Ltd. diacyl peroxide-based peroxide A (brand name: Niper BMT-K40, solid content concentration: 40 mass%, 10 hour half-life temperature: 73.1 °C) was prepared by Otsuka Chemical Co., Ltd. non-cyanic polymerization initiator A (brand name: OTAZO-15, Solid content concentration: 100 mass %, 10 hour half-life temperature: 61 degreeC), and except having made the compounding quantity 0.6 mass part, it carried out similarly to Example 4, and produced the adhesive tape.

(Example 26)

Nichiyu Co., Ltd. diacyl peroxide-based peroxide A (brand name: Niper BMT-K40, solid content concentration: 40 mass%, 10 hour half-life temperature: 73.1 °C) was prepared by Otsuka Chemical Co., Ltd. azo polymerization initiator B (brand name: AIBN, solid content concentration :100 mass %, 10 hour half-life temperature: 65 degreeC), except having changed the compounding quantity into 0.6 mass part, it carried out similarly to Example 4, and produced the adhesive tape.

(Example 27)

Except for changing α-aminoalkylphenone photopolymerization initiator A (trade name: OmniRad 369) manufactured by IGM Resins BV to α-hydroxyalkylphenone photopolymerization initiator B (trade name: OmniRad 184) manufactured by IGM Resins BV It carried out similarly to Example 5, and produced the adhesive tape.

(Example 28)

Examples except that α-aminoalkylphenone photoinitiator A (trade name: OmniRad 369) manufactured by IGM Resins BV was changed to bisacylphosphine oxide photoinitiator C (trade name: OmniRad 819) manufactured by IGM Resins BV. In the same manner as in 5, an adhesive tape was produced.

(Example 29)

Urethane acrylate oligomer A (trade name: Atresin UN-3320HA, weight average molecular weight: 1,500, number of functional groups: 6, double bond equivalent: 250) manufactured by Negami Industries Co., Ltd. Trade name: Atresin UN-904, weight average molecular weight: 4,900, number of functional groups: 10, double bond equivalent: 490), except that it was changed in the same manner as in Example 24 to prepare an adhesive tape.

(Example 30)

Urethane acrylate oligomer A (trade name: Atresin UN-3320HA, weight average molecular weight: 1,500, number of functional groups: 6, double bond equivalent: 250) manufactured by Negami Industrial Co., Ltd. : Magnetoluminescent UV-7000B, weight average molecular weight: 3,500, number of functional groups: 2.5, double bond equivalent: 1,400), Nichiyu Co., Ltd. diacyl peroxide-based peroxide A (brand name: Niper BMT-K40, solid content concentration An adhesive tape was produced in the same manner as in Example 5, except that the blending amount of :40% by mass, 10 hour half-life temperature:73.1°C) was changed to 9.0 parts by mass (3.6 parts by mass in terms of solid content).

(Example 31)

An adhesive tape was produced in the same manner as in Example 5 except that the weight average molecular weight of the acrylic adhesive polymer B was adjusted to 300,000 by controlling the initiator concentration. In addition, the content of the carbon-carbon double bond of the acrylic adhesive polymer F was 0.84 mmol/g.

(Example 32)

A pressure-sensitive adhesive tape was produced in the same manner as in Example 5, except that the weight average molecular weight of the acrylic pressure-sensitive polymer B was adjusted to 1.5 million by controlling the initiator concentration and polymerization time. In addition, the content of the carbon-carbon double bond of the acrylic adhesive polymer G was 0.82 mmol/g.

(Example 33)

Crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 µm, crosslinking degree: standard, strength at 30% deformation in micro-compression test: 55 MPa) manufactured by Soken Chemical Co., Ltd. An adhesive tape was produced in the same manner as in Example 5 except that the crosslinked acrylic filler G (trade name: Techpolymer BM30X-12, average particle diameter 12 µm, strength at 30% deformation in micro-compression test: 29 MPa) was changed. .

(Example 34)

Crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 μm, degree of crosslinking: standard, strength at 30% deformation in micro-compression test: 55 MPa) manufactured by Soken Chemical Co., Ltd. Acrylic filler D (trade name: Art Pearl J-4P, average particle diameter: 2.2 µm, crosslinking degree: low, strength at 30% deformation in micro-compression test: 70 MPa), and the dry thickness of the pressure-sensitive adhesive layer was 10 µm Except having changed to, it carried out similarly to Example 5, and produced the adhesive tape.

(Comparative Example 1)

Crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 µm, crosslinking degree: standard, strength at 30% deformation in micro-compression test: 55 MPa) manufactured by Soken Chemical Co., Ltd. An adhesive tape was produced in the same manner as in Example 2 except that oxide-based peroxide A (trade name: Niper BMT-K40, solid content concentration: 40 mass%, 10 hour half-life temperature: 73.1°C) was not blended.

(Comparative Example 2)

Crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 µm, crosslinking degree: standard, strength at 30% deformation in micro-compression test: 55 MPa) manufactured by Soken Chemical Co., Ltd. An adhesive tape was produced in the same manner as in Example 5 except that oxide-based peroxide A (trade name: Niper BMT-K40, solid content concentration: 40 mass%, 10 hour half-life temperature: 73.1°C) was not blended.

(Comparative Example 3)

An adhesive tape was produced in the same manner as in Example 5, except that the following acrylic adhesive polymer H having no carbon-carbon double bond was used as the acrylic adhesive polymer.

<Production of acrylic adhesive polymer H>

As a copolymerization monomer component, 2-ethylhexyl acrylate (2-EHA), 2-hydroxyethyl acrylate (2-HEA), methyl acrylate (MA), and methacrylic acid (MAA) were prepared. These copolymerization monomer components are mixed so that the copolymerization ratio of 2-EHA/2-HEA/MA/MAA = 10% by mass/10% by mass/78% by mass/2% by mass is used, and ethyl acetate is used as a solvent to obtain a solution radical. The acrylic adhesive polymer H (solid content concentration: 35% by mass) was synthesized by polymerization. In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor. When the weight average molecular weight of the synthesized acrylic adhesive polymer H was measured by gel permeation chromatography (GPC, solvent: tetrahydrofuran), it was 800,000.

(Comparative Example 4)

Crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 μm, crosslinking degree: standard, strength at 30% deformation in micro-compression test: 55 MPa) made by Soken Chemical Co., Ltd. It carried out similarly to Example 5, and produced the adhesive tape.

(Comparative Example 5)

Crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 μm, degree of crosslinking: standard, strength at 30% deformation in micro-compression test: 55 MPa) manufactured by Soken Chemical Co., Ltd. An adhesive tape was produced in the same manner as in Example 5 except that the urethane-based filler A (trade name: JB-400CB, average particle diameter: 15 µm, strength at 30% deformation in micro-compression test: 8.5 MPa) was changed.

(Comparative Example 6)

A pressure-sensitive adhesive tape was prepared in the same manner as in Example 27 except that Nichiyu Corporation's diacyl peroxide-based peroxide A (brand name: Niper BMT-K40, solid content concentration: 40 mass%, 10 hour half-life temperature: 73.1°C) was not blended. .

(Comparative Example 7)

An adhesive tape was produced in the same manner as in Example 1, except that the following acrylic adhesive polymer I having no carbon-carbon double bond was used as the acrylic adhesive polymer, and the preparation of the adhesive solution was changed to the following.

<Preparation of acrylic adhesive polymer I>

As the copolymerization monomer component, 2-ethylhexyl acrylate (2-EHA), n-butyl acrylate (BA), and 2-hydroxyethyl acrylate (2-HEA) were prepared. These copolymerization monomer components are mixed so as to have a copolymerization ratio of 2-EHA/BA/2-HEA=20% by mass/75% by mass/5% by mass, and an acrylic adhesive polymer by solution radical polymerization using ethyl acetate as a solvent. I (solid content concentration: 35% by mass) was synthesized. In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor. When the weight average molecular weight of the synthesized acrylic adhesive polymer I was measured by gel permeation chromatography (GPC, solvent: tetrahydrofuran), it was 800,000.

<Preparation of adhesive solution>

Polyfunctional acrylate A (ethoxylated isocyanuric acid triacrylate, brand name: A-9300 manufactured by Shin-Nakamura Chemical Industries, Ltd.) with respect to 303.0 parts by mass of the solution of the acrylic adhesive polymer I prepared above (100 parts by mass in terms of solid content). , Molecular weight: 423, number of functional groups: 3, double bond equivalent: 141) 100 parts by mass, crosslinked acrylic filler D (trade name: Artpearl J-4P, average particle diameter: 2.2 µm, crosslinking degree: low, manufactured by Negami Industries, Ltd.) Strength at 30% deformation in the micro-compression test: 70 MPa) in a ratio of 2.0 parts by mass and uniformly stirred, then α-hydroxyalkylphenone-based photoinitiator B (trade name) manufactured by IGM Resins BV as a photoinitiator (trade name) : 1.0 parts by mass of OmniRad 184), an isocyanate crosslinking agent A (brand name: Coronate L, solid content concentration: 75% by mass) manufactured by Tosoh Corporation as a crosslinking agent was blended in a ratio of 4.0 parts by mass (3.0 parts by mass in terms of solid content). , Diluted with ethyl acetate and stirred to prepare a pressure-sensitive adhesive solution having a solid content concentration of 33% by mass.

(Comparative Example 8)

Crosslinked acrylic filler D (trade name: Art Pearl J-4P, average particle diameter: 2.2 µm, crosslinking degree: low, strength at 30% deformation in micro-compression test: 70 MPa) manufactured by Negami Industries, Ltd. Crosslinked acrylic filler E (brand name: Artpearl J-7P, average particle diameter: 6 µm, crosslinking degree: low, strength at 30% deformation in micro-compression test: 69 MPa), and the blending amount was set to 20 parts by mass. Except that, it carried out similarly to Comparative Example 7 and produced the adhesive tape.

(Comparative Example 9)

The blending amount of the crosslinked acrylic filler E (trade name: Artpearl J-7P, average particle diameter: 6 µm, crosslinking degree: low, strength at 30% deformation in micro-compression test: 69 MPa) manufactured by Negami Industries Co., Ltd. is 60 parts by mass. Except having done, it carried out similarly to Comparative Example 8, and produced the adhesive tape.

(Comparative Example 10)

Crosslinked acrylic filler E (trade name: Art Pearl J-7P, average particle diameter: 6 µm, crosslinking degree: low, strength at 30% deformation in micro compression test: 69 MPa) manufactured by Negami Industries, Ltd. Similar to Comparative Example 9 except that it was changed to a crosslinked acrylic filler F (trade name: Artpearl GR-600 transparent, average particle diameter: 10 µm, degree of crosslinking: medium, strength at 30% deformation in micro compression test: 60 MPa). Thus, an adhesive tape was produced.

(Comparative Example 11)

80 mass of the crosslinked acrylic filler F (trade name: Artpearl GR-600 transparent, average particle diameter: 10 µm, crosslinking degree: medium, strength at 30% deformation in micro compression test: 60 MPa) manufactured by Negami Industries Co., Ltd. Except having changed to negative, it carried out similarly to Comparative Example 10, and produced the adhesive tape.

(Comparative Example 12)

A pressure-sensitive adhesive tape was produced in the same manner as in Example 1, except that the preparation of the pressure-sensitive adhesive solution was changed to the following without using an acrylic pressure-sensitive adhesive polymer.

<Preparation of adhesive solution>

Toyochem's urethane-based prepolymer A (trade name: Cyabine SH-101, hydroxyl value: 18 mgKOH/g, solid content concentration: 60% by mass), based on 167 parts by mass (100 parts by mass in terms of solid content), manufactured by Shinnakamura Chemical Co., Ltd. Polyfunctional acrylate B (dipentaerythritol polyacrylate [mixture of 5-functional and 6-functional acrylate], brand name: A-9550, hydroxyl value: 53 mgKOH/g, double bond equivalent [mass of prepolymer per mole of double bond] :110 g/mol) was blended in a ratio of 75 parts by mass, stirred uniformly, and then peroxydicarbonate-based peroxide D (trade name: ferroyl TCP, solid content concentration: 100% by mass, 10 hours) manufactured by Nichis as a thermal polymerization initiator. Half-life temperature: 40.8°C) 1.5 parts by mass, 2.0 parts by mass of acylphosphine oxide photopolymerization initiator E (trade name: Omnirad TPO H) manufactured by IGM Resins BV as a photoinitiator, and 3M Japan ionic liquid charging as an antistatic agent 5.0 parts by mass of inhibitor A (brand name: FC4400), and 32.9 parts by mass (14.8 parts by mass of solid content) of isocyanate-based cross-linking agent B (trade name: Coronate L-45E, solid content concentration: 45% by mass) manufactured by Tosoh Corporation as a crosslinking agent. It blended at a ratio, diluted with ethyl acetate, and stirred to prepare a pressure-sensitive adhesive solution having a solid content concentration of 33% by mass.

(Comparative Example 13)

10.0 parts by mass of peroxydicarbonate-based peroxide D (trade name: ferroyl TCP, solid content concentration: 100% by mass, 10 hour half-life temperature: 40.8°C) manufactured by Nichiyu Corporation is 10.0 parts by mass, and isocyanate-based crosslinking agent B (trade name: An adhesive tape was produced in the same manner as in Comparative Example 12 except that coronate L-45E, solid content concentration: 45% by mass) was changed to 49.3 parts by mass (22.2 parts by mass in terms of solid content).

(Comparative Example 14)

A pressure-sensitive adhesive tape was produced in the same manner as in Example 1, except that the preparation of the pressure-sensitive adhesive solution was changed to the following without using an acrylic pressure-sensitive adhesive polymer.

<Preparation of adhesive solution>

Toyochem's urethane-based prepolymer B (brand name: Cyabine SH-109, solid content 64 mass%) 156.3 parts by mass (solid content conversion 100 parts by mass), Sartomer Co., Ltd. polyfunctional acrylate C (pentaerythritol tetraacrylic) Rate, brand name: SR295, molecular weight: 352, number of functional groups: 4, double bond equivalent: 88) were blended in a ratio of 75 parts by mass, stirred uniformly, and then diacyl peroxide-based peroxide A manufactured by Nichiyu as a thermal polymerization initiator. (Brand name: Niper BMT-K40, solid content concentration: 40 mass%, 10 hour half-life temperature: 73.1°C) 9.38 parts by mass (solid content conversion 3.75 parts by mass) as a photoinitiator, and acylphosphine oxide-based photopolymerization manufactured by IGM Resins BV 2 parts by mass of initiator E (trade name: Omnirad TPO H), 32.9 parts by mass of isocyanate crosslinking agent B (trade name: Coronate L-45E, solid content concentration: 45% by mass) manufactured by Tosoh Corporation as a crosslinking agent (14.8 parts by mass in terms of solid content) (Part), diluted with ethyl acetate, and stirred to prepare a pressure-sensitive adhesive solution having a solid content concentration of 33% by mass.

(Comparative Example 15)

An adhesive tape was prepared in the same manner as in Comparative Example 14 except that the isocyanate crosslinking agent B (brand name: Coronate L-45E, solid content concentration: 45% by mass) manufactured by Tosoh Corporation was changed to 49.3 parts by mass (22.2 parts by mass in terms of solid content). did.

(Comparative Example 16)

In addition to the pressure-sensitive adhesive solution, as a filler, crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle diameter: 20 μm, degree of crosslinking: standard, strength at 30% deformation in micro-compression test: 55 MPa) ) Was added in the same manner as in Comparative Example 15 to prepare an adhesive tape.

2. Evaluation method of adhesive tape

The adhesive tapes produced in Examples 1 to 34 and Comparative Examples 1 to 16 were cut to a width of 25 mm, and these were used as test pieces.

2.1 Measurement of initial adhesion

For each test piece of the above adhesive tape, according to the method described in the adhesive tape/adhesive sheet test method (JIS Z 0237 (2009)), the adhesive strength test (before heating treatment) to the glass plate in the state of the glass plate (peeling adhesive force test) ).

Specifically, the peeling film of the adhesive tape was peeled off, affixed to prevent air bubbles from entering the glass plate having the affixed surface well cleaned, and then a roller having a mass of 2000 g was reciprocated once at a rate of 5 mm/sec, followed by compression bonding, at a temperature of 23°C. , And left to stand for 20 minutes in an environment of 50% RH of humidity to obtain a measurement sample. Subsequently, using a tensile tester, the glass plate was peeled off at a rate of 300 mm/min in the 90° direction, and the initial adhesive strength to the glass plate was measured. In addition, the environment at the time of affixing and measurement was made into temperature 23 degreeC and humidity 50%RH.

Although it does not specifically limit as an initial adhesive force in a state, It is preferable that it is 0.5 N/10 mm or more from the viewpoint of the easiness of attaching an adherend and retention of an adherend at the time of processing. Considering also the phenomenon of increase in adhesive force when placed under a higher temperature condition, it is more preferable to set it in the range of 0.5N/10mm to 3.5N/10mm.

The initial adhesive strength at the time of the state was evaluated according to the following judgment criteria, and the evaluation of (circle) was taken as the pass.

○: 0.5N/10㎜ or more

×: less than 0.5N/10mm

2.2 Measurement of adhesive force after heat treatment

For each test piece of the above adhesive tape, in accordance with the method described in the adhesive tape/adhesive sheet test method (JIS Z 0237 (2009)), in the same manner as the initial adhesive force measurement, the adhesive strength test after heat treatment to the glass plate (removal Adhesion test) was performed.

Specifically, after the peeling film of the adhesive tape was peeled off and affixed so as not to allow air bubbles to enter the glass plate on which the affixed surface was well cleaned, a roller having a mass of 2000 g was reciprocated once at a speed of 5 mm/sec, followed by compression bonding. Subsequently, the glass plate to which the adhesive tape was affixed was stored and taken out under the following three heat treatment conditions, and then left to stand for 2 hours or more in an environment at a temperature of 23° C. and a humidity of 50% RH to obtain a measurement sample. Subsequently, using a tensile tester, the glass plate was peeled off at a rate of 300 mm/min in the 90° direction, and the adhesive force after the heat treatment with respect to the glass plate was measured. In addition, the environment at the time of affixing and measurement was made into temperature 23 degreeC and humidity 50%RH.

Heat treatment conditions (1): storage at 165℃ for 1 hour

Heat treatment conditions (2): storage at 165℃ for 3 hours

Heat treatment conditions (3): storage at 200℃ for 1 hour

The adhesive force after the heat treatment is preferably 0.5 N/10 mm or more from the viewpoint of holding the adherend during processing under high temperature conditions. In consideration of the effect of reducing adhesive force due to further irradiation with active energy rays, it is more preferable to set it in the range of 0.5 N/10 mm to 2.5 N/10 mm.

The adhesive force after the heat treatment was evaluated according to the following judgment criteria, and the evaluation of ○ was set as the pass.

○: 0.5N/10㎜ or more

×: less than 0.5N/10mm

2.3 Measurement of adhesion after ultraviolet (UV) irradiation

Using the measurement sample prepared in 2.1 (before heating treatment: condition) and the measurement sample prepared in 2.2 (after heating treatment: 3 conditions), for each test piece of the adhesive tape, the adhesive tape/adhesive sheet test method (JIS Z 0237 (2009)), in the same manner as the initial adhesive strength measurement, an adhesive strength test (peel adhesion test) after ultraviolet (UV) irradiation to the glass plate was performed.

Specifically, for the measurement sample prepared in 2.1 (before heating treatment) and the measurement sample prepared in 2.2 (after heating treatment), a high-pressure mercury lamp (model H04-L21) manufactured by Eye Graphics was used, and the accumulated amount of light was 500 mJ/cm 2 Ultraviolet ray (UV) was irradiated from the side to which the adhesive tape was affixed so that it might become. Subsequently, using a tensile tester, the glass plate was removed at a rate of 300 mm/min in the 90° direction, and the adhesive force after irradiation with ultraviolet rays (UV) to the glass plate was measured. In addition, the environment at the time of affixing and measurement was made into temperature 23 degreeC and humidity 50%RH.

In the state before heat treatment, the adhesive force after ultraviolet (UV) irradiation is preferably a value as small as possible in consideration of the phenomenon of increase in the adhesive force when placed under high temperature conditions. Specifically, it is preferable to set it as 0.10 N/10 mm or less, and it is more preferable to set it as 0.05 N/10 mm or less.

The adhesive strength after ultraviolet (UV) irradiation in the state before heat treatment was evaluated according to the following judgment criteria, and the evaluation of ○ was set as the pass.

○: 0.10N/10㎜ or less

×: exceeding 0.10N/10㎜

In addition, after heat treatment, considering the level at which the adherend can be easily detached (peeled) without contamination or damage, as the adhesive force after ultraviolet (UV) irradiation, 0.25 N/10 mm or less (lower limit: 0 N/10 Mm), and more preferably 0.10 N/10 mm or less.

The adhesive force after ultraviolet (UV) irradiation after the heat treatment was evaluated according to the following judgment criteria, and the evaluation of ○ was set as the pass.

○: 0.25N/10㎜ or less

×: exceeding 0.25N/10㎜

2.4 Evaluation of contamination of the surface of the glass plate

When the adhesive force after ultraviolet irradiation was measured in 2.3 above, the staining property of the surface of the glass plate after peeling each adhesive tape was evaluated.

Specifically, the surface of the glass plate was observed with the naked eye and a microscope, and the state of the area of the residue of the pressure-sensitive adhesive composition relative to the area to which the pressure-sensitive adhesive tape was adhered was evaluated according to the following criteria. In addition, evaluation of (double-circle) or (circle) was made into pass.

◎: The total area of the residue relative to the adhesive tape affixed area is less than 1%

○: The total area of the residue relative to the adhesive tape affixed area is 1% or more and less than 5%

△: The total area of the residue relative to the adhesive tape affixed area is 5% or more and less than 25%

×: the total area of the residue relative to the adhesive tape affixed area is 25% or more

3. Comprehensive evaluation of adhesive tape

The general evaluation of the adhesive tape was evaluated based on the following criteria. In addition, evaluation of A or B was judged to be a level usable as an adhesive tape for temporary fixing of an electronic member for practical use, and it was set as pass.

A: When all evaluations of adhesive strength are ○, and all evaluations of contamination are ◎

B: When the evaluation of adhesive strength is all ○, and the evaluation of fouling property includes O as the pass level

C: When the evaluation of adhesive force is all ○, and the evaluation of staining property includes △, or the evaluation of adhesive force includes ×, and the evaluation of staining property is △ to ◎

D: Regardless of the evaluation of adhesive strength, when the contamination evaluation includes ×

Tables 1 to 6 show the composition of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape. In Tables 7 to 12, the properties and evaluation results of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape are shown.

As shown in Tables 7 to 10, the pressure-sensitive adhesive layer has a carbon-carbon double bond and an acrylic adhesive polymer having a functional group, a photopolymerization initiator, a thermal polymerization initiator, a crosslinking agent, and a strength at 30% deformation in a microcompression test of 20 MPa or more. In the adhesive tapes of Examples 1 to 34 containing a filler, under any conditions, preferable results were obtained in all evaluation items of the initial adhesive strength, the adhesive strength after ultraviolet (UV) irradiation, and the contamination state of the surface of the glass plate after desorption. Confirmed. Thereby, it turns out that the adhesive tape of this embodiment is useful as an adhesive tape for temporary fixation of an electronic member which requires processing under a high temperature condition of about 165 to 200 degreeC, for example.

In contrast, as shown in Tables 11 to 12, in the adhesive tapes of Comparative Examples 1 to 16 in which the adhesive layer does not satisfy the present embodiment, initial adhesive strength, adhesive force after ultraviolet (UV) irradiation, and contamination of the surface of the glass plate after desorption In the evaluation items of the state, it was confirmed that certain evaluation results were inferior to those of the adhesive tapes of Examples 1 to 34.

Specifically, in the adhesive tapes of Comparative Examples 1 and 2 in which the adhesive layer did not contain a filler and a thermal polymerization initiator, compared with Examples 2 and 5, in the more stringent heat treatment conditions 2 and 3, at the time of heat treatment. Since the adhesive force increased significantly, the adhesive force did not sufficiently decrease even after irradiation with ultraviolet rays (UV) later. In addition, in the adhesive tape of Comparative Example 1, contamination was clearly observed on the surface of the glass plate.

In the adhesive tape of Comparative Example 3 in which an acrylic adhesive polymer having no carbon-carbon double bond was used as the acrylic adhesive polymer in the adhesive layer, compared to Examples 2, 5, 9, 11, 31 and 32, under certain heat treatment conditions. Also in the case of heat treatment, since the adhesive force increased significantly, the adhesive force did not sufficiently decrease even after irradiation with ultraviolet rays (UV). In addition, contamination was clearly observed on the surface of the glass plate.

In the pressure-sensitive adhesive tape of Comparative Example 4 in which no filler was contained in the pressure-sensitive adhesive layer, compared with Example 5, under the more stringent heat treatment conditions 2 and 3, the adhesive strength did not sufficiently decrease even when irradiated with ultraviolet rays (UV). In addition, a little contamination was observed on the surface of the glass plate.

In the adhesive tape of Comparative Example 5 using a crosslinked urethane-based filler having a strength of 8.5 MPa less than 20 MPa at 30% deformation in the micro-compression test as a filler as a filler in the pressure-sensitive adhesive layer, compared to Example 5, more stringent heat treatment conditions In 2 and 3, even if irradiated with ultraviolet rays (UV), the adhesive force did not fall sufficiently.

In the adhesive tape of Comparative Example 6 in which the adhesive layer did not contain a thermal polymerization initiator, compared to Example 5, in the more stringent heat treatment conditions 2 and 3, the adhesive strength increased during the heat treatment. ), the adhesive strength did not sufficiently decrease. In addition, in the heat treatment condition 3, a little contamination was observed on the surface of the glass plate.

A comparison that contains a filler in the adhesive layer, but uses an acrylic adhesive polymer that does not have a carbon-carbon double bond as an acrylic adhesive polymer, uses a polyfunctional acrylate instead of a urethane acrylate oligomer, and does not contain a thermal polymerization initiator. In the adhesive tapes of Examples 7 to 11, as compared with the examples, under any heat treatment conditions, the adhesive strength significantly increased during the heat treatment, so that the adhesive strength did not sufficiently decrease even after irradiation with ultraviolet rays (UV). In addition, contamination was clearly observed on the surface of the glass plate.

Although the adhesive layer contains a thermal polymerization initiator, in the adhesive tapes of Comparative Examples 12 to 15 in which a urethane-based prepolymer and a polyfunctional acrylate are used instead of the acrylic adhesive polymer and the urethane acrylate oligomer, and no filler is contained, Examples Compared with, in any heat treatment conditions, contamination was clearly observed on the surface of the glass plate. In addition, even after irradiation with ultraviolet rays (UV), there were cases in which the adhesive strength did not sufficiently decrease. In addition, in the adhesive tapes of Comparative Examples 13 to 15, the initial adhesive strength was low even under any heat treatment conditions.

In the adhesive tape of Comparative Example 16 containing a filler with respect to Comparative Example 15, under any heat treatment conditions, the adhesive strength after ultraviolet (UV) irradiation was at a pass level, but the initial adhesive strength was low, and contamination was clearly observed on the surface of the glass plate. Became.

Claims (10)

An adhesive tape having a sheet-like substrate that transmits active energy rays and an adhesive layer provided on the surface of the sheet-like substrate,
The pressure-sensitive adhesive layer contains an acrylic pressure-sensitive adhesive polymer having a carbon-carbon double bond and a functional group, a photoinitiator, a thermal polymerization initiator, a crosslinking agent reacting with the functional group, and a filler,
The said filler is an adhesive tape whose strength at the time of 30% deformation|transformation in a micro compression test is 20 MPa or more. The method of claim 1,
The adhesive tape containing the thermal polymerization initiator in an amount ranging from 0.1 to 31.0 parts by mass based on 100 parts by mass of the acrylic adhesive polymer having a carbon-carbon double bond and a functional group. The method according to claim 1 or 2,
When the average particle diameter of the filler is R (µm) and the thickness of the pressure-sensitive adhesive layer is D (µm), the ratio of R to D (R/D) is in the range of 0.20 to 1.00. The method according to any one of claims 1 to 3,
The adhesive tape having an average particle diameter of the filler in the range of 2 to 30 µm. The method according to any one of claims 1 to 4,
The adhesive tape contained in the range of 1.0 to 62.0 parts by mass of the filler based on 100 parts by mass of the acrylic adhesive polymer having a carbon-carbon double bond and a functional group. The method according to any one of claims 1 to 5,
An adhesive tape having a carbon-carbon double bond content of the acrylic adhesive polymer having a carbon-carbon double bond and a functional group in the range of 0.40 to 1.85 mmol/g. The method according to any one of claims 1 to 6,
The pressure-sensitive adhesive layer is an adhesive tape comprising an oligomer having a carbon-carbon double bond. The method of claim 7,
The oligomer having a carbon-carbon double bond has two or more carbon-carbon double bonds, a carbon-carbon double bond equivalent in the range of 250 to 1,400, and a weight average molecular weight in the range of 1,500 to 4,900 adhesive tape. The method according to claim 7 or 8,
The adhesive tape containing the oligomer having a carbon-carbon double bond in an amount of up to 120 parts by mass based on 100 parts by mass of the acrylic adhesive polymer having a carbon-carbon double bond and a functional group. The method according to any one of claims 1 to 9,
The adhesive tape is an adhesive tape for temporarily fixing an electronic member.