High frequency dielectric heating adhesive

Abstract

Provided is an adhesive agent (adhesive sheet 1A) for high-frequency induction heating, the adhesive agent (adhesive sheet 1A) for high-frequency induction heating containing at least a thermoplastic resin (A) and a dielectric filler (B) that emits heat when a high-frequency electrical field is applied. The thermoplastic resin (A) contains at least a first thermoplastic resin (A1) and a second thermoplastic resin (A2). The first thermoplastic resin (A1) is a silane-modified thermoplastic resin, and the second thermoplastic resin (A2) is a non-silane-modified thermoplastic resin.

Description

[Technical Field]

[0001] The present invention relates to an adhesive for high frequency dielectric heating. [Background technology]

[0002] In recent years, methods have been proposed for bonding adherends that are generally difficult to bond together, such as by interposing an adhesive made of a specific resin blended with a heat-generating material between the adherends and performing dielectric heating treatment, induction heating treatment, ultrasonic welding treatment, laser welding treatment, or the like. When glass is used as the adherend, the following techniques are available as adhesion methods.

[0003] For example, Patent Document 1 describes a thermoplastic resin composition for bonding glass and inorganic reinforced thermoplastic resin, which contains a heating element that generates heat by high-frequency induction and a thermoplastic resin with a melting point of 90°C to 200°C that has been modified with a monomer containing a functional group that reacts with inorganic matter in the presence of moisture.

[0004] As another bonding method, for example, Patent Document 2 describes a glass adhesion sheet for adhering to a glass surface by a vacuum lamination method, and this glass adhesion sheet contains a silane-modified polyethylene resin in which an ethylenically unsaturated silane compound is graft-polymerized onto low-density polyethylene. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-097445 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-068426 Summary of the Invention [Problem to be solved by the invention]

[0006] When the thermoplastic resin composition described in Patent Document 1 is used, a large amount of energy is consumed for bonding to glass, and when the glass-adhering sheet described in Patent Document 2 is used, the pressure must be maintained for a long time during vacuum lamination, which is necessary for bonding to glass. In addition, the composition or sheet used for bonding to glass is also required to have adhesive strength that does not decrease during storage after production until use.

[0007] An object of the present invention is to provide an adhesive for high-frequency dielectric heating that can bond to glass with high adhesive strength even with low energy consumption and that is less likely to lose adhesive strength over time. [Means for solving the problem]

[0008] According to one aspect of the present invention, there is provided a high-frequency dielectric heating adhesive, the high-frequency dielectric heating adhesive comprising at least a thermoplastic resin (A) and a dielectric material that generates heat upon application of a high-frequency electric field, the thermoplastic resin (A) comprising at least a first thermoplastic resin (A1) and a second thermoplastic resin (A2), the first thermoplastic resin (A1) being a silane-modified thermoplastic resin, and the second thermoplastic resin (A2) being a non-silane-modified thermoplastic resin.

[0009] In the adhesive for high-frequency dielectric heating according to one aspect of the present invention, the first thermoplastic resin (A1) is preferably a silane-modified polyolefin resin.

[0010] In the adhesive for high-frequency dielectric heating according to one aspect of the present invention, the second thermoplastic resin (A2) is preferably a polyolefin resin that is not silane-modified.

[0011] In the adhesive for high-frequency dielectric heating according to one aspect of the present invention, the second thermoplastic resin (A2) preferably has a polar moiety.

[0012] In the adhesive for high-frequency dielectric heating according to one aspect of the present invention, the polar moiety of the second thermoplastic resin (A2) is preferably an acidic moiety.

[0013] In the adhesive for high-frequency dielectric heating according to one aspect of the present invention, the acidic site of the second thermoplastic resin (A2) preferably has an acid anhydride structure.

[0014] In the adhesive for high-frequency dielectric heating according to one aspect of the present invention, the first thermoplastic resin (A1) preferably contains ethylene or propylene as a main component.

[0015] In the adhesive for high-frequency dielectric heating according to one aspect of the present invention, the second thermoplastic resin (A2) preferably contains ethylene or propylene as a main component.

[0016] In the high-frequency dielectric heating adhesive according to one embodiment of the present invention, it is preferable that the main composition of the first thermoplastic resin (A1) and the main composition of the second thermoplastic resin (A2) are the same.

[0017] In a high-frequency dielectric heating adhesive according to one embodiment of the present invention, it is preferable that the volume content of the first thermoplastic resin (A1) in the thermoplastic resin (A) contained in the high-frequency dielectric heating adhesive is 15% by volume or more and 80% by volume or less.

[0018] In the adhesive for high-frequency dielectric heating according to one aspect of the present invention, the MFR of the thermoplastic resin (A) at 190° C. is preferably 2 g / 10 min or more and 50 g / 10 min or less.

[0019] In the high-frequency dielectric heating adhesive according to one aspect of the present invention, the volume content of the dielectric material in the high-frequency dielectric heating adhesive is preferably 5% by volume or more and 50% by volume or less.

[0020] In the adhesive for high-frequency dielectric heating according to one aspect of the present invention, the dielectric material is preferably a dielectric filler (B).

[0021] In the high-frequency dielectric heating adhesive according to one aspect of the present invention, the dielectric filler (B) preferably contains at least one selected from the group consisting of zinc oxide, silicon carbide, barium titanate, and titanium oxide.

[0022] In the adhesive for high-frequency dielectric heating according to one embodiment of the present invention, the dielectric filler (B) preferably has a volume average particle diameter of 1 μm or more and 30 μm or less. The volume average particle diameter is determined by measuring the particle size distribution of the dielectric filler (B) by a laser diffraction / scattering method and calculating the volume average particle diameter from the results of the particle size distribution measurement in accordance with JIS Z 8819-2:2001.

[0023] The high-frequency dielectric heating adhesive according to one aspect of the present invention is preferably an adhesive sheet.

[0024] According to one aspect of the present invention, it is possible to provide an adhesive for high-frequency dielectric heating that can bond to glass with high adhesive strength even with low energy consumption and that is less likely to lose adhesive strength over time. [Brief explanation of the drawings]

[0025] [Figure 1A] 1 is a schematic cross-sectional view of a high-frequency dielectric heating adhesive sheet according to one embodiment. FIG. [Figure 1B] 1 is a schematic cross-sectional view of a high-frequency dielectric heating adhesive sheet according to one embodiment. FIG. [Figure 1C] 1 is a schematic cross-sectional view of a high-frequency dielectric heating adhesive sheet according to one embodiment. FIG. [Figure 2] FIG. 1 is a schematic diagram illustrating a high-frequency dielectric heating process using a high-frequency dielectric heating adhesive sheet and a dielectric heating device according to one embodiment. [Figure 3A] 1 is a schematic perspective view showing an example of the shape of a molded body according to an embodiment. FIG. [Figure 3B] 1 is a schematic perspective view showing an example of the shape of a molded body according to an embodiment. FIG. [Figure 3C] 1 is a schematic perspective view showing an example of the shape of a molded body according to an embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0026] [High frequency dielectric heating adhesive] The high-frequency dielectric heating adhesive of this embodiment contains at least a thermoplastic resin (A) and a dielectric material that generates heat upon application of a high-frequency electric field, the thermoplastic resin (A) containing at least a first thermoplastic resin (A1) and a second thermoplastic resin (A2), the first thermoplastic resin (A1) being a silane-modified thermoplastic resin, and the second thermoplastic resin (A2) being another thermoplastic resin different from the silane-modified thermoplastic resin. A high-frequency electric field is an electric field whose direction reverses at high frequencies.

[0027] The dielectric material is a material that generates heat when a high-frequency electric field is applied, and is preferably a material that generates heat when a high-frequency electric field in the frequency range of 3 MHz or more and 300 MHz or less is applied. The dielectric material is preferably at least one of a dielectric resin and a dielectric filler (B). From the viewpoint of easily suppressing deterioration of the dielectric material contained in the high-frequency dielectric heating adhesive sheet when the high-frequency dielectric heating adhesive sheet is processed, the dielectric material is more preferably a dielectric filler (B). Hereinafter, a case where the high-frequency dielectric heating adhesive sheet according to this embodiment contains a dielectric filler (B) as the dielectric material will be described.

[0028] <Thermoplastic resin (A)> In this embodiment, the high-frequency dielectric heating adhesive contains at least two types of thermoplastic resins (A). In this embodiment, the high-frequency dielectric heating adhesive contains at least a first thermoplastic resin (A1) and a second thermoplastic resin (A2).

[0029] In this embodiment, the first thermoplastic resin (A1) is a silane-modified thermoplastic resin. The silane-modified thermoplastic resin as the first thermoplastic resin (A1) is not particularly limited as long as it is a silane-modified thermoplastic resin, but is preferably at least one selected from the group consisting of a copolymer of a silyl group-containing compound and a thermoplastic resin, and a silane-modified thermoplastic resin obtained by graft-polymerizing a thermoplastic resin with a silyl group-containing compound.

[0030] In this embodiment, the second thermoplastic resin (A2) is a thermoplastic resin that is not silane-modified. The second thermoplastic resin (A2) is not particularly limited as long as it is a thermoplastic resin that is not silane-modified.

[0031] High-frequency dielectric heating adhesives containing a silane-modified thermoplastic resin as the thermoplastic resin (A) tend to achieve high adhesive strength to glass. However, high-frequency dielectric heating adhesives containing only a silane-modified thermoplastic resin as the thermoplastic resin tend to exhibit a decrease in adhesive strength. This decrease in adhesive strength is thought to occur because the silane-modified thermoplastic resin is prone to water absorption, and crosslinking reactions between reactive groups in the silane-modified thermoplastic resin progress over time. When a high-frequency dielectric heating adhesive contains not only a silane-modified thermoplastic resin but also a non-silane-modified thermoplastic resin as a thermoplastic resin, unintended deterioration of adhesiveness over time is suppressed. Since the high-frequency dielectric heating adhesive according to this embodiment also contains a non-silane-modified thermoplastic resin, it is thought that water absorption by the high-frequency dielectric heating adhesive is suppressed and reactive groups are separated from each other, making it difficult for crosslinking reactions to proceed. Furthermore, when a high-frequency dielectric heating adhesive contains both a silane-modified thermoplastic resin and a non-silane-modified thermoplastic resin, it is easy to adjust the viscosity of the high-frequency dielectric heating adhesive and to impart processability to the high-frequency dielectric heating adhesive.

[0032] The thermoplastic resins in the first thermoplastic resin (A1) and the second thermoplastic resin (A2) are preferably each independently at least one selected from the group consisting of polyolefin-based resins, styrene-based resins, polyacetal-based resins, polycarbonate-based resins, poly(meth)acrylic-based resins, polyamide-based resins, polyimide-based resins, polyvinyl acetate-based resins, phenoxy-based resins, and polyester-based resins, for example, from the viewpoint of being easily meltable and having a predetermined heat resistance.

[0033] The thermoplastic resin in the silane-modified thermoplastic resin is preferably a polyolefin-based resin. That is, the first thermoplastic resin (A1) is preferably a silane-modified polyolefin-based resin. If the first thermoplastic resin (A1) is a silane-modified polyolefin, it is easy to obtain a high-frequency dielectric heating adhesive that has excellent moldability, is easily melted by high-frequency dielectric heating, and has high adhesiveness. The moldability of a high-frequency dielectric heating adhesive refers to the ease with which the high-frequency dielectric heating adhesive can be processed into a desired form (e.g., a sheet or molded product). In this specification, the high-frequency dielectric heating adhesive according to this embodiment, which is in the form of an adhesive sheet, may be referred to as a high-frequency dielectric heating adhesive sheet.

[0034] The thermoplastic resin in the non-silane-modified thermoplastic resin is preferably a polyolefin-based resin. That is, the second thermoplastic resin (A2) is preferably a non-silane-modified polyolefin-based resin. If the second thermoplastic resin (A2) is a non-silane-modified polyolefin-based resin, it is easy to obtain a high-frequency dielectric heating adhesive that has excellent moldability, is easily melted by high-frequency dielectric heating, and has high adhesiveness. Because polyolefins themselves are highly hydrophobic, non-silane-modified polyolefin-based resins are also highly effective in suppressing deterioration of adhesive performance over time.

[0035] It is more preferable that the first thermoplastic resin (A1) is a silane-modified polyolefin resin and the second thermoplastic resin (A2) is a non-silane-modified polyolefin resin. The silane-modified polyolefin resin and the non-silane-modified polyolefin resin have excellent compatibility. Therefore, by containing both the silane-modified polyolefin resin and the non-silane-modified polyolefin resin, it becomes easier to obtain an adhesive for high-frequency dielectric heating that has excellent moldability, high adhesiveness, and is less likely to deteriorate over time.

[0036] The silane-modified polyolefin resin is not particularly limited, but is preferably at least one selected from the group consisting of a copolymer of a silyl group-containing compound and an olefin, and a silane-modified polyolefin obtained by graft polymerizing a polyolefin with a silyl group-containing compound.

[0037] The olefin copolymerized with the silyl group-containing compound is preferably, for example, an α-olefin having 2 to 20 carbon atoms, and the α-olefin having 2 to 20 carbon atoms is preferably at least one olefin selected from the group consisting of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methyl-1-pentene, 4-methyl-1-hexene, and 4,4-dimethyl-1-pentene, and more preferably at least one olefin selected from the group consisting of ethylene and propylene. The olefin copolymerized with the silyl group-containing compound may be one type or two or more types. The polyolefin to be graft polymerized with a silyl group-containing compound includes a homopolymer of the above olefin and a copolymer of two or more olefins, and a homopolymer or copolymer having a monomer unit derived from at least one of ethylene and propylene is preferred. Also preferred is a silane-modified polyolefin obtained by graft polymerizing a polyolefin having a reactive group in advance with a silyl group-containing compound.

[0038] Examples of silyl group-containing compounds include vinylsilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinyltriphenoxysilane, vinyltribenzyloxysilane, vinyltrimethylenedioxysilane, vinylpropionyloxysilane, vinyltriacetoxysilane, vinyltricarboxysilane, vinyltriacetylsilane, vinyltrichlorosilane, vinyltrismethylethylketoximesilane, vinyltriisopropenoxysilane, and vinylmethyldimethoxysilane; (meth)acrylic silanes such as (meth)acryloxymethyltrimethoxysilane; and styryl silanes such as styryltrimethoxysilane. In this specification, "(meth)acrylic" is a term used to refer to both "acrylic" and "methacrylic", and the same applies to other similar terms.

[0039] The polyolefin resin in the first thermoplastic resin (A1) and the second thermoplastic resin (A2) is preferably, for example, a resin made of a homopolymer such as polyethylene, polypropylene, polybutene, or polymethylpentene, or an α-olefin resin made of a copolymer of a monomer selected from the group consisting of ethylene, propylene, butene, hexene, octene, and 4-methylpentene.

[0040] The main component of the first thermoplastic resin (A1) is preferably ethylene or propylene, from the viewpoint of obtaining a high-frequency dielectric heating adhesive that has excellent mechanical strength, high moldability, and stable adhesive properties.

[0041] The main component of the second thermoplastic resin (A2) is preferably ethylene or propylene, from the viewpoint of obtaining a high-frequency dielectric heating adhesive that has excellent mechanical strength, high moldability, and stable adhesive properties.

[0042] In this specification, the "main composition of the thermoplastic resin" refers to, for example, when the thermoplastic resin is a polymer, the repeating unit contained in the polymer that is most abundant in the polymer. When the thermoplastic resin is a polymer derived from a single monomer, the monomer unit (repeating unit) is the "main composition of the thermoplastic resin." When the thermoplastic resin is a copolymer, the repeating unit contained in the polymer that is most abundant is the "main composition of the thermoplastic resin." When the thermoplastic resin is a copolymer, the "main composition of the thermoplastic resin" in the copolymer refers to repeating units (monomer units) that are contained in an amount of 30% by mass or more, in one embodiment, repeating units that are contained in an amount of more than 30% by mass, in another embodiment, repeating units that are contained in an amount of 40% by mass or more, and in yet another embodiment, repeating units that are contained in an amount of 50% by mass or more. Furthermore, when the thermoplastic resin is a copolymer, the repeating units contained in the majority may be two or more types.

[0043] It is preferable that the main composition of the first thermoplastic resin (A1) and the main composition of the second thermoplastic resin (A2) are the same. For example, when the first thermoplastic resin (A1) is a silane-modified polypropylene containing 50% by mass or more of propylene units as repeating units, and the second thermoplastic resin (A2) is a maleic anhydride-modified polypropylene containing 50% by mass or more of propylene units as repeating units, the main composition (repeating units) of the first thermoplastic resin (A1) and the main composition (repeating units) of the second thermoplastic resin are both propylene, and the main compositions of the first thermoplastic resin (A1) and the second thermoplastic resin are the same. When the main composition of the first thermoplastic resin (A1) and the main composition of the second thermoplastic resin (A2) are the same, the compatibility between the first thermoplastic resin (A1) and the second thermoplastic resin (A2) is improved, and the reactive groups of the first thermoplastic resin (A1) are more easily separated from each other.

[0044] The volume content of the first thermoplastic resin (A1) in the thermoplastic resin (A) contained in the high-frequency dielectric heating adhesive is preferably 15% by volume or more, more preferably 25% by volume or more, and even more preferably 40% by volume or more. The volume content of the first thermoplastic resin (A1) in the thermoplastic resin (A) contained in the high-frequency dielectric heating adhesive is preferably 80% by volume or less, more preferably 70% by volume or less, and even more preferably 60% by volume or less. When the volume content of the first thermoplastic resin (A1) in the thermoplastic resin (A) is 15% by volume or more, adhesion to glass is easily achieved. When the volume content of the first thermoplastic resin (A1) in the thermoplastic resin (A) is 80% by volume or less, storage stability is easily obtained.

[0045] The volume content of the second thermoplastic resin (A2) in the thermoplastic resin (A) contained in the high-frequency dielectric heating adhesive is preferably 20% by volume or more, more preferably 30% by volume or more, and even more preferably 40% by volume or more. The volume content of the second thermoplastic resin (A2) in the thermoplastic resin (A) contained in the high-frequency dielectric heating adhesive is preferably 85% by volume or less, more preferably 75% by volume or less, and even more preferably 60% by volume or less. When the volume content of the second thermoplastic resin (A2) in the thermoplastic resin (A) is 20% by volume or more, the high-frequency dielectric heating adhesive tends to have good storage stability. When the volume content of the second thermoplastic resin (A2) in the thermoplastic resin (A) is 85% by volume or less, it becomes easier to prevent a decrease in adhesiveness to glass.

[0046] However, the sum of the volume content of the first thermoplastic resin (A1) and the volume content of the second thermoplastic resin (A2) in the thermoplastic resin (A) contained in the high-frequency dielectric heating adhesive is 100 mass % or less.

[0047] The volume ratio of the first thermoplastic resin (A1) to the second thermoplastic resin (A2) in the high-frequency dielectric heating adhesive is preferably 15:85 to 80:20, more preferably 25:75 to 70:30, and even more preferably 40:60 to 60:40.

[0048] The second thermoplastic resin (A2) preferably has a polar moiety. Examples of polar moieties include a hydroxyl group, a carboxyl group, an epoxy group, an acryloyl group, an acetoxy group, a sulfo group, a phospho group, a phenol group, a vinyl acetate structure, and an acid anhydride structure. The polar moiety may be introduced into the resin by copolymerization or by modification. Thermoplastic resins having polar moieties are preferred because they exhibit high adhesive strength to adherends. The second thermoplastic resin (A2) is preferably a polyolefin resin having polar moieties.

[0049] When the high-frequency dielectric heating adhesive contains a first thermoplastic resin (A1) and a second thermoplastic resin (A2) having a polar moiety, the volume ratio of the first thermoplastic resin (A1) to the second thermoplastic resin (A2) having a polar moiety in the high-frequency dielectric heating adhesive is preferably 15:85 to 80:20, more preferably 25:75 to 70:30, and even more preferably 40:60 to 60:40.

[0050] The polar moiety of the second thermoplastic resin (A2) is also preferably an acidic moiety. The second thermoplastic resin (A2) is more preferably a polyolefin resin having an acidic moiety. Examples of the acidic moiety of the second thermoplastic resin (A2) include a carboxy group, a sulfo group, a phospho group, a phenol group, and an acid anhydride structure. When the second thermoplastic resin (A2) has an acidic moiety, it is possible to suppress a decrease in adhesive performance that accompanies a decrease in the proportion of the silane-modified thermoplastic resin in the high-frequency dielectric heating adhesive.

[0051] The second thermoplastic resin (A2) is also preferably a resin having an acid-modified structure as a polar moiety, and more preferably a polyolefin resin having an acid-modified structure. The acid-modified structure as a polar moiety is a moiety introduced by acid-modifying a thermoplastic resin (e.g., a polyolefin resin). Examples of compounds used to acid-modify a thermoplastic resin (e.g., a polyolefin resin) include unsaturated carboxylic acid derivative components derived from unsaturated carboxylic acids, acid anhydrides of unsaturated carboxylic acids, and esters of unsaturated carboxylic acids. In this specification, polyolefin resins having an acid-modified structure may be referred to as acid-modified polyolefin resins.

[0052] Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid.

[0053] Examples of the acid anhydrides of unsaturated carboxylic acids include acid anhydrides of unsaturated carboxylic acids such as maleic anhydride, itaconic anhydride, and citraconic anhydride.

[0054] Examples of the esters of unsaturated carboxylic acids include esters of unsaturated carboxylic acids such as methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dimethyl maleate, monomethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl itaconate, diethyl itaconate, dimethyl citraconate, diethyl citraconate, and dimethyl tetrahydrophthalic anhydride.

[0055] (Polyolefin resin with polar moieties) The polar moiety in the polyolefin resin having a polar moiety is not particularly limited as long as it is a moiety that can impart polarity to the polyolefin resin. Polyolefin resins having a polar moiety are preferred because they exhibit high adhesive strength to adherends. The polyolefin resin having a polar moiety may be a copolymer of an olefin monomer and a monomer having a polar moiety, or may be a resin obtained by introducing a polar moiety into an olefin polymer obtained by polymerization of an olefin monomer by modification such as an addition reaction.

[0056] The type of olefinic monomer constituting the polyolefinic resin having a polar moiety is not particularly limited. Examples of the olefinic monomer include ethylene, propylene, butene, hexene, octene, and 4-methyl-1-pentene. The olefinic monomer may be used alone or in combination of two or more. The olefin-based monomer is preferably at least one of ethylene and propylene, from the viewpoint of obtaining an adhesive for high-frequency dielectric heating having excellent mechanical strength and stable adhesive properties. The olefin-derived structural unit in the polyolefin-based resin having a polar moiety is preferably a structural unit derived from ethylene or propylene.

[0057] When the polyolefin resin as the second thermoplastic resin (A2) is a copolymer of an olefin monomer and a monomer having a polar moiety, the copolymer preferably contains 2% by mass or more, more preferably 4% by mass or more, even more preferably 5% by mass or more, and even more preferably 6% by mass or more of structural units derived from the monomer having a polar moiety. The copolymer preferably contains 30% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less, and even more preferably 15% by mass or less of structural units derived from the monomer having a polar moiety. When the copolymer contains 2% by mass or more of structural units derived from monomers having a polar moiety, the adhesive strength of the high-frequency dielectric heating adhesive is improved. Furthermore, when the copolymer contains 30% by mass or less of structural units derived from monomers having a polar moiety, the tackiness of the second thermoplastic resin (A2) can be prevented from becoming too strong. As a result, it becomes easier to prevent difficulties in molding the high-frequency dielectric heating adhesive.

[0058] When the polyolefin resin as the second thermoplastic resin (A2) is a copolymer of an olefin monomer and a monomer having an acidic moiety, the proportion of the constituent units derived from the monomer having an acidic moiety in the copolymer is preferably in the same range as the proportion of the constituent units derived from the monomer having a polar moiety in the copolymer of an olefin monomer and a monomer having a polar moiety, and the effects obtained by being within this range are also the same as when the polyolefin resin as the second thermoplastic resin (A2) is a copolymer of an olefin monomer and a monomer having a polar moiety.

[0059] When the polyolefin resin as the second thermoplastic resin (A2) has an acid-modified structure, the modification rate with acid is preferably 0.01 mass% or more, more preferably 0.1 mass% or more, and even more preferably 0.2 mass% or more. When the polyolefin resin as the second thermoplastic resin (A2) has an acid-modified structure, the modification rate with acid is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less. When the second thermoplastic resin (A2) has an acid-modified structure, the acid modification rate of 0.01% by mass or more improves the adhesive strength of the high-frequency dielectric heating adhesive. Furthermore, the acid modification rate of 30% by mass or less prevents the second thermoplastic resin (A2) from becoming too tacky. As a result, it becomes easier to prevent the high-frequency dielectric heating adhesive from becoming difficult to mold. In this specification, the degree of modification by an acid is the percentage of the mass of the portion derived from the acid relative to the total mass of the acid-modified polyolefin.

[0060] The acidic moiety of the second thermoplastic resin (A2) preferably has an acid anhydride structure. The second thermoplastic resin (A2) is more preferably a polyolefin resin having an acid anhydride structure. When the second thermoplastic resin (A2) has an acid anhydride structure, interaction with the dielectric filler (B) is suppressed, and therefore an increase in torque and gelation can be suppressed when the high-frequency dielectric heating adhesive is molded into a sheet. The acid anhydride structure is more preferably a maleic anhydride structure. The maleic anhydride structure may be a group introduced by graft-modifying a thermoplastic resin, or may be a maleic anhydride copolymer obtained by copolymerizing a monomer containing a maleic anhydride structure.

[0061] In the maleic anhydride-modified polyolefin, the modification rate with maleic anhydride is preferably in the same range as the modification rate when the polyolefin resin as the second thermoplastic resin (A2) has an acid-modified structure, and the effects obtained by being in this range are also the same as when the polyolefin resin as the second thermoplastic resin (A2) has an acid-modified structure. When the maleic anhydride-modified polyolefin is a copolymer of an olefinic monomer and a monomer containing a maleic anhydride structure, the proportion of the structural units derived from the monomer containing a maleic anhydride structure in the copolymer is preferably in the same range as the proportion of the structural units derived from the monomer containing a polar moiety in the copolymer of an olefinic monomer and a monomer containing a polar moiety, and the effects obtained by being within this range are also the same as when the polyolefin resin as the second thermoplastic resin (A2) is a copolymer of an olefinic monomer and a monomer containing a polar moiety.

[0062] The olefin-derived structural units in the maleic anhydride-modified polyolefin are preferably structural units derived from ethylene or propylene, i.e., the maleic anhydride-modified polyolefin is preferably a maleic anhydride-modified polyethylene resin or a maleic anhydride-modified polypropylene resin.

[0063] (MFR of thermoplastic resin) The MFR of the thermoplastic resin (A) at 190° C. is preferably 2 g / 10 min or more, more preferably 2.5 g / 10 min or more, and even more preferably 3 g / 10 min or more. The MFR of the thermoplastic resin (A) at 190° C. is preferably 50 g / 10 min or less, more preferably 30 g / 10 min or less, and even more preferably 20 g / 10 min or less. When the thermoplastic resin (A) has an MFR of 2 g / 10 min or more at 190°C, the sheet formability is excellent, and the high-frequency dielectric heating adhesive spreads well during bonding, making it easy to obtain bonding strength in a short time. By ensuring that the MFR of the thermoplastic resin (A) at 190°C is 50 g / 10 min or less, it is easy to prevent the viscosity of the high-frequency dielectric heating adhesive from becoming too low during dielectric heating treatment. If the viscosity of the high-frequency dielectric heating adhesive becomes too low, the amount of resin between the adherends decreases during bonding, making it difficult to obtain adhesive strength, but by preventing viscosity reduction, it is easier to obtain adhesive strength. The MFR of the thermoplastic resin (A) at 190°C can be measured by the method described in the Examples section below.

[0064] <Dielectric filler (B)> The dielectric filler (B) is a filler that generates heat when a high-frequency electric field is applied. The dielectric filler (B) is preferably a filler that generates heat when a high-frequency electric field in the frequency range of 3 MHz or more and 300 MHz or less is applied to it. The dielectric filler (B) is preferably a filler that generates heat when a high-frequency electric field in the frequency range of 3 MHz or more and 300 MHz or less is applied to it, for example, a frequency of 13.56 MHz, 27.12 MHz, or 40.68 MHz.

[0065] (kinds) The dielectric filler (B) is preferably an inorganic material having crystal water such as zinc oxide, silicon carbide (SiC), anatase type titanium oxide, barium titanate, barium titanate zirconate, lead titanate, potassium niobate, rutile type titanium oxide, hydrated aluminum silicate, hydrated aluminosilicate of an alkali metal, or an inorganic material having crystal water such as hydrated aluminosilicate of an alkaline earth metal, either alone or in combination of two or more.

[0066] The dielectric filler (B) preferably contains at least one selected from the group consisting of zinc oxide, silicon carbide, barium titanate, and titanium oxide.

[0067] Among the dielectric fillers listed above, zinc oxide is more preferred as the dielectric filler (B) because it is available in a wide variety of shapes and sizes, allowing for the adhesive properties and mechanical properties of the high-frequency dielectric heating adhesive to be improved to suit the application. By using zinc oxide as the dielectric filler (B), a colorless high-frequency dielectric heating adhesive can be obtained. Because zinc oxide has a low density among dielectric fillers, when adherends are bonded using a high-frequency dielectric heating adhesive containing zinc oxide as the dielectric filler (B), the total weight of the bonded body is less likely to increase compared to when adhesives containing other dielectric fillers are used. Zinc oxide is not too hard, even among ceramics, so it is less likely to damage the manufacturing equipment for the high-frequency dielectric heating adhesive. Because zinc oxide is an inactive oxide, it causes less damage to thermoplastic resins when blended with them. Furthermore, the titanium oxide as the dielectric filler (B) is preferably at least one of anatase type titanium oxide and rutile type titanium oxide, and from the viewpoint of excellent dielectric properties, anatase type titanium oxide is more preferable.

[0068] (volume content) The volume content of the dielectric filler (B) in the adhesive for high-frequency dielectric heating is preferably 5% by volume or more, more preferably 8% by volume or more, and even more preferably 10% by volume or more. The volume content of the dielectric filler (B) in the high-frequency dielectric heating adhesive is preferably 50% by volume or less, more preferably 40% by volume or less, even more preferably 35% by volume or less, and even more preferably 25% by volume or less. When the volume content of the dielectric filler (B) in the high-frequency dielectric heating adhesive is 5% by volume or more, heat generation properties are improved and it becomes easier to firmly bond the high-frequency dielectric heating adhesive to a glass adherend. By ensuring that the volume content of the dielectric filler (B) in the high-frequency dielectric heating adhesive is 50 volume % or less, it becomes easier to obtain flexibility as a sheet and to prevent a decrease in toughness, making it easier to process the high-frequency dielectric heating adhesive into the desired shape in subsequent processes.

[0069] Since the high-frequency dielectric heating adhesive according to this embodiment contains a thermoplastic resin (A) and a dielectric filler (B), the volume content of the dielectric filler (B) relative to the total volume of the thermoplastic resin (A) and the dielectric filler (B) is preferably 5% by volume or more, more preferably 8% by volume or more, and even more preferably 10% by volume or more. The volume content of the dielectric filler (B) relative to the total volume of the thermoplastic resin (A) and the dielectric filler (B) is preferably 50% by volume or less, more preferably 40% by volume or less, even more preferably 35% by volume or less, and even more preferably 25% by volume or less.

[0070] In the above, the volume content of the dielectric material in the adhesive layer has been described as the volume content when the dielectric material is a dielectric filler (B). The volume content of the dielectric material in the adhesive layer is not limited to when the dielectric material is a dielectric filler (B), and even when the dielectric material is a dielectric material other than the dielectric filler (B), it is preferable that the volume content be in the same range as the volume content of the dielectric filler (B) in the adhesive layer. That is, the volume content of the dielectric material in the adhesive layer is preferably 5% by volume or more and 50% by volume or less.

[0071] (Average particle size) The volume average particle size of the dielectric filler (B) is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 3 μm or more. The volume average particle size of the dielectric filler (B) is preferably 30 μm or less, more preferably 25 μm or less, and even more preferably 20 μm or less. When the volume average particle diameter of the dielectric filler (B) is 1 μm or more, the high-frequency dielectric heating adhesive exhibits high heat-generating performance when a high-frequency electric field is applied, and the high-frequency dielectric heating adhesive can be firmly bonded to a glass substrate in a short period of time. By making the volume average particle diameter of the dielectric filler (B) 30 μm or less, the high-frequency dielectric heating adhesive exhibits high heat-generating performance when a high-frequency electric field is applied, and the high-frequency dielectric heating adhesive can be firmly bonded to glass adherends in a short time. In addition, by making the volume average particle diameter of the dielectric filler (B) 30 μm or less, a decrease in the strength of the high-frequency dielectric heating adhesive can be prevented.

[0072] The volume average particle diameter of the dielectric filler (B) is measured by the following method: The particle size distribution of the dielectric filler (B) is measured by a laser diffraction / scattering method, and the volume average particle diameter is calculated from the results of the particle size distribution measurement in accordance with JIS Z 8819-2:2001.

[0073] When the high-frequency dielectric heating adhesive according to this embodiment is an adhesive sheet (high-frequency dielectric heating adhesive sheet), the average particle diameter D of the dielectric filler (B) F and the thickness T of the high frequency dielectric heating adhesive sheet, and 1≦T / D F It is preferable that the relationship be ≦2500. T / D F is preferably 1 or more, more preferably 2 or more, more preferably 5 or more, more preferably 10 or more, and even more preferably 20 or more. F If the value is 1 or more, it is possible to prevent a decrease in adhesive strength caused by contact between the dielectric filler (B) and the adherend during adhesion. T / D Fis preferably 2500 or less, preferably 2000 or less, preferably 1750 or less, more preferably 1000 or less, even more preferably 500 or less, even more preferably 100 or less, and even more preferably 50 or less. F If the value is 2500 or less, the load on the sheet manufacturing apparatus can be reduced when the high frequency dielectric heating adhesive sheet is produced.

[0074] (additives) The high-frequency dielectric heating adhesive according to this embodiment may or may not contain an additive. When the high-frequency dielectric heating adhesive according to this embodiment is a high-frequency dielectric heating adhesive sheet consisting of multiple layers, at least one of the multiple layers may or may not contain an additive. When at least one of the multiple layers contains an additive, the adhesive layer containing the high-frequency dielectric heating adhesive among the multiple layers may or may not contain an additive.

[0075] When the high-frequency dielectric heating adhesive according to this embodiment contains an additive, examples of the additive include a tackifier, a plasticizer, a wax, a colorant, an antioxidant, an ultraviolet absorber, an antibacterial agent, a coupling agent, a viscosity modifier, an organic filler, an inorganic filler, etc. The organic filler and inorganic filler as additives are different from the dielectric material (dielectric filler).

[0076] Tackifiers and plasticizers can improve the melting and adhesive properties of the high frequency dielectric heating adhesive. Examples of tackifiers include rosin derivatives, polyterpene resins, aromatic modified terpene resins, hydrogenated aromatic modified terpene resins, terpene phenol resins, coumarone-indene resins, aliphatic petroleum resins, aromatic petroleum resins, and hydrogenated aromatic petroleum resins. Examples of plasticizers include petroleum-based process oils, natural oils, dialkyl dibasic acids, and low-molecular-weight liquid polymers. Examples of petroleum-based process oils include paraffin-based process oils, naphthenic process oils, and aromatic process oils. Examples of natural oils include castor oil and tall oil. Examples of dialkyl dibasic acids include dibutyl phthalate, dioctyl phthalate, and dibutyl adipate. Examples of low-molecular-weight liquid polymers include liquid polybutene and liquid polyisoprene.

[0077] When the high-frequency dielectric heating adhesive according to this embodiment contains an additive, the content of the additive in the high-frequency dielectric heating adhesive is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, based on the total amount of the high-frequency dielectric heating adhesive. The content of the additive in the high-frequency dielectric heating adhesive is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0078] The high-frequency dielectric heating adhesive according to this embodiment preferably does not contain a solvent. A solvent-free high-frequency dielectric heating adhesive is less likely to cause problems with VOCs (volatile organic compounds) that are caused by the adhesive used to bond the adhesive to the adherend.

[0079] The high-frequency dielectric heating adhesive according to this embodiment preferably does not contain conductive materials such as carbon or carbon compounds containing carbon as a main component (e.g., carbon black), metals, etc. The adhesive layer preferably does not contain, for example, carbon steel, α-iron, γ-iron, δ-iron, copper, brass, aluminum, iron-nickel alloy, iron-nickel-chromium alloy, carbon fiber, or carbon black.

[0080] When the high-frequency dielectric heating adhesive of this embodiment contains a conductive substance, the content of the conductive substance in the adhesive is, independently of one another, preferably 20 mass % or less, more preferably 10 mass % or less, even more preferably 5 mass % or less, even more preferably 1 mass % or less, and even more preferably 0.1 mass % or less, based on the total amount of the adhesive. It is particularly preferable that the content of the conductive material in the adhesive is 0% by mass. If the content of the conductive substance in the adhesive is 20 mass % or less, it becomes easier to prevent the problem of carbonization of the bonded portion and the adherend due to electrical breakdown during dielectric heating treatment.

[0081] In the high-frequency dielectric heating adhesive according to this embodiment, the total content of the thermoplastic resin (A) and the dielectric filler (B) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 99% by mass or more.

[0082] <Form and characteristics of high frequency dielectric heating adhesive> The form of the high-frequency dielectric heating adhesive according to this embodiment is not particularly limited, but may be, for example, a sheet or a molded body. In this specification, a molded body is not a sheet. A sheet usually refers to a discrete object with a uniform thickness of 1 mm or less, 2 mm or less, or 5 mm or less.

[0083] (High frequency dielectric heating adhesive sheet) The high-frequency dielectric heating adhesive according to this embodiment is preferably an adhesive sheet (high-frequency dielectric heating adhesive sheet). In one aspect, the high-frequency dielectric heating adhesive sheet according to this embodiment is composed of only one adhesive layer made of the high-frequency dielectric heating adhesive according to this embodiment, and in another aspect, it may be composed of multiple layers. When the high-frequency dielectric heating adhesive sheet is composed of only one adhesive layer, the adhesive layer itself corresponds to the high-frequency dielectric heating adhesive sheet, and therefore the shape and properties of the high-frequency dielectric heating adhesive sheet correspond to the shape and properties of the adhesive layer.

[0084] In one embodiment, the high-frequency dielectric heating adhesive sheet according to this embodiment is composed of only one adhesive layer having high-frequency dielectric adhesive properties. However, the high-frequency dielectric heating adhesive sheet is not limited to an embodiment consisting of only one adhesive layer, and other embodiments of the high-frequency dielectric heating adhesive sheet include an embodiment in which layers other than the adhesive layer are laminated. In this way, a high-frequency dielectric heating adhesive sheet may consist of only one adhesive layer with high-frequency dielectric adhesive properties, and therefore, in this specification, the terms "high-frequency dielectric heating adhesive sheet" and "adhesive layer" may be interchangeable in some cases. 1A to 1C show schematic diagrams of a number of aspects of the high-frequency dielectric heating adhesive sheet according to this embodiment.

[0085] 1A is composed of only a single adhesive layer 10. The high frequency dielectric heating adhesive sheet 1A has a first surface 11 and a second surface 12 opposite to the first surface 11. The high-frequency dielectric heating adhesive sheet preferably consists of only a single adhesive layer, which allows the high-frequency dielectric heating adhesive sheet to be thin and easy to mold.

[0086] The high-frequency dielectric heating adhesive sheet 1B shown in FIG. 1B has an adhesive layer 10 and a substrate 30 that supports the adhesive layer 10. Like the high-frequency dielectric heating adhesive sheet 1A, the adhesive layer 10 has a first surface 11. The substrate 30 is not particularly limited as long as it is a material that can support the adhesive layer 10. Examples include a resin film or resin sheet containing at least one resin selected from the group consisting of polyolefin resins such as polyethylene resin and polypropylene resin, polyester resins such as polybutylene terephthalate resin and polyethylene terephthalate resin, acetate resin, ABS resin, polystyrene resin, and vinyl chloride resin. The substrate 30 may contain a dielectric filler (B), and the dielectric filler (B) in the adhesive layer 10 and the dielectric filler in the substrate 30 may be the same or different.

[0087] The high-frequency dielectric heating adhesive sheet 1C shown in Fig. 1C has an adhesive layer 10, an adhesive layer 20, and an intermediate layer 40 disposed between the adhesive layer 10 and the adhesive layer 20. The high-frequency dielectric heating adhesive sheet 1C has a first surface 11 and a second surface 21 opposite to the first surface 11. The adhesive layer 10 in the high-frequency dielectric heating adhesive sheet 1C may be referred to as a first adhesive layer, and the adhesive layer 20 may be referred to as a second adhesive layer. In a high-frequency dielectric heating adhesive sheet having an intermediate layer disposed between the first adhesive layer and the second adhesive layer, it is sufficient that the first adhesive layer satisfies the conditions of the adhesive layers of the high-frequency dielectric heating adhesive sheet of this embodiment. In one aspect, both the first adhesive layer and the second adhesive layer are layers with the same composition and properties. In another aspect, the second adhesive layer is a high-frequency dielectric heating adhesive layer that differs from the first adhesive layer in at least one of its composition and properties. In another aspect, the second adhesive layer is a general adhesive layer that is not a high-frequency dielectric heating adhesive layer. Examples of the second adhesive layer that is not high-frequency dielectric heating adhesive include a layer of a drying and solidifying type adhesive that dries and solidifies as water or a solvent evaporates, or an adhesive layer formed from an adhesive (pressure-sensitive adhesive).

[0088] Thickness of high frequency dielectric heating adhesive sheet The thickness of the high frequency dielectric heating adhesive sheet according to this embodiment is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 30 μm or more, and even more preferably 50 μm or more. If the thickness of the high-frequency dielectric heating adhesive sheet is 5 μm or more, the high-frequency dielectric heating adhesive sheet can easily conform to the irregularities of the adherend when adhering to the adherend, and adhesive strength can be easily achieved. When the high-frequency dielectric heating adhesive sheet has a multilayer structure consisting of multiple layers, the thickness of the adhesive layer is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 30 μm or more, and even more preferably 50 μm or more. When the high-frequency dielectric heating adhesive sheet is a multi-layered sheet, if the thickness of the adhesive layer is 5 μm or more, the adhesive layer will easily conform to the unevenness of the adherend when adhering to the adherend, making it easier to develop adhesive strength. There is no particular upper limit to the thickness of the high-frequency dielectric heating adhesive sheet. As the thickness of the high-frequency dielectric heating adhesive sheet increases, the weight of the entire bonded body obtained by bonding the high-frequency dielectric heating adhesive sheet to the adherend also increases. Therefore, it is preferable that the high-frequency dielectric heating adhesive sheet has a thickness within a range that does not cause problems in practical use. Taking into consideration the practicality and formability of the high-frequency dielectric heating adhesive sheet, the thickness of the high-frequency dielectric heating adhesive sheet is preferably 2000 μm or less, more preferably 1000 μm or less, and even more preferably 600 μm or less.

[0089] An adhesive sheet used as a high-frequency dielectric heating adhesive is easier to handle than a liquid adhesive that must be applied, and workability during bonding to an adherend is improved.

[0090] Furthermore, adhesive sheets used as high-frequency dielectric heating adhesives can be controlled in thickness and other dimensions as needed. This allows them to be used in roll-to-roll processes, and they can be processed into any desired area and shape by punching or other processes to match the bonding area with the adherend and the shape of the adherend. Therefore, adhesive sheets used as high-frequency dielectric heating adhesives have significant advantages from the perspective of the manufacturing process.

[0091] (molded body) The high-frequency dielectric heating adhesive according to this embodiment is also preferably a molded body. The form of the molded body according to this embodiment is not particularly limited. Schematic perspective views showing examples of the form of the molded body according to this embodiment are shown in FIGS. 3A to 3C. The molded body according to this embodiment may be a molded body consisting of a single part molded from the high-frequency dielectric heating adhesive according to this embodiment, or may be a molded body consisting of multiple parts. For example, there is a molded body having a first part made of the high-frequency dielectric heating adhesive according to this embodiment (first material) and a second part made of a second material that is different from the first material of the first part.

[0092] The molded body 1D shown in Fig. 3A has a cubic shape and includes a first portion 10D and a second portion 20D having a volume larger than that of the first portion 10D.

[0093] The shape of molded body 1E shown in Figure 3B is also a cube. Molded body 1D and molded body 1E differ in the position and proportion of the first portion in the cube. In molded body 1D, first portion 10D contacts the entire bottom surface of second portion 20D. In contrast, in molded body 1E, first portion 10E is located at a corner of the cube and contacts second portion 20E.

[0094] The molded body according to this embodiment may have multiple first portions. For example, the molded body 1F shown in Fig. 3C has a hollow, substantially cylindrical second portion 20F with a portion cut out along the axial direction, and two first portions 10F that contact the two cut-out end faces of the cylinder of second portion 20F. The number of first portions in the molded body is not limited to two, and may be three or more.

[0095] The form of the molded body according to the present invention is not limited to the examples shown in molded bodies 1D, 1E, and 1F. In addition, in the examples shown in molded bodies 1D, 1E, and 1F, the first portion and the second portion are in direct contact with each other, but the present invention is not limited to the embodiment in which the first portion and the second portion are in direct contact with each other, and the first portion and the second portion may be in contact with each other via another portion (for example, a third portion, etc.).

[0096] In the molded body according to this embodiment, the second portion is made of a second material. The second material is not particularly limited. Preferably, the second material includes at least one material selected from the group consisting of organic materials, inorganic materials, and naturally occurring materials. Examples of organic materials include thermoplastic resins and thermosetting resins. Examples of inorganic materials include ceramics, glass, and metals. Examples of naturally occurring materials include wood, paper, leather, and stone. In the molded body according to this embodiment, the first material and the second material are different. The term "different between the first material and the second material" means that all of the components contained in the first material do not match all of the components contained in the second material. For example, if the first material is a material containing a silane-modified thermoplastic resin (first thermoplastic resin (A1)), another thermoplastic resin (second thermoplastic resin (A2)) different from the silane-modified thermoplastic resin, and zinc oxide, and the second material is a material containing only the silane-modified thermoplastic resin, the second material does not contain the other thermoplastic resin or zinc oxide, and therefore all of the components of the first material and the second material do not match, and the first material and the second material are different.

[0097] (Method of manufacturing high frequency dielectric heating adhesive) The high-frequency dielectric heating adhesive according to this embodiment can be produced, for example, by mixing the above-mentioned components. When the high-frequency dielectric heating adhesive according to this embodiment is an adhesive sheet, the manufacturing method is not particularly limited, and it can be manufactured, for example, as follows: A single-layer high-frequency dielectric heating adhesive sheet can be manufactured by premixing the above-mentioned components and kneading them using a known kneading device such as an extruder or a heated roll, and then by a known molding method such as extrusion molding, calendar molding, injection molding, or casting molding. When the high-frequency dielectric heating adhesive sheet according to this embodiment has a multilayer structure, it can be produced, for example, by premixing the above-mentioned components and coextrusion using a multilayer extruder. Alternatively, a multilayer sheet can be produced by individually preparing single-layer sheets for each layer (e.g., the first adhesive layer, intermediate layer, and second adhesive layer) that make up the high-frequency dielectric heating adhesive sheet according to this embodiment, and then laminating multiple single-layer sheets together. When laminating multiple single-layer sheets, for example, a thermal laminator can be used. In addition, the high-frequency dielectric heating adhesive sheet according to this embodiment can also be produced by thermal extrusion coating, in which a molten adhesive layer is coated onto a substrate, or by hot melt coating, or by wet coating, in which a coating liquid in which the adhesive layer composition is dispersed or dissolved in a solvent is coated onto a substrate.

[0098] When the high-frequency dielectric heating adhesive according to this embodiment is a molded body, the manufacturing method is not particularly limited, but it can be manufactured, for example, as follows. When the molded article according to this embodiment is a molded article made of a single part molded from the high-frequency dielectric heating adhesive (first material), it can be produced by a single-color molding method. 3A to 3C, it can be manufactured by a multi-color molding method using multiple materials (for example, a first material and a second material). Alternatively, a multi-color molded article can be manufactured by fitting a molded article consisting of a single part molded from a high-frequency dielectric heating adhesive (first material) into another molded article.

[0099] Furthermore, a multicolor molded body can be produced by insert molding using a first molded body made of one of the first material and the second material and the other of the first material and the second material. For example, even when the second material is metal or ceramic, a second part made of metal or ceramic and having a desired shape may be prepared, and the molded body according to this embodiment may be manufactured by insert molding using this second part and the first material.

[0100] Furthermore, for example, the molded body according to this embodiment can be manufactured by molding a first molded body by injection molding or compression molding using one of the first material and the second material, and then by insert molding using the other of the first material and the second material and the first molded body. For example, a first molded body is molded using the second material by injection molding or compression molding. This first molded body corresponds to the second part. Next, a molded body may be produced by insert molding using the first material and the first molded body. The part made of the first material formed during insert molding corresponds to the first part.

[0101] (How to use high frequency dielectric heating adhesive) The high-frequency dielectric heating adhesive according to this embodiment can be used to bond to an adherend. The high-frequency dielectric heating adhesive according to this embodiment can also be used to bond multiple adherends together. The material of the adherend is not particularly limited, and may be either an organic material or an inorganic material (including metal materials), or may be a composite material of an organic material and an inorganic material. Examples of organic materials that can be used as the adherend include plastic materials and rubber materials. Examples of plastic materials include polypropylene resin, polyethylene resin, polyurethane resin, acrylonitrile-butadiene-styrene copolymer resin (ABS resin), polycarbonate resin (PC resin), polyamide resin (such as nylon 6 and nylon 66), polyester resin (such as polyethylene terephthalate (PET resin) and polybutylene terephthalate resin (PBT resin)), polyacetal resin (POM resin), polymethyl methacrylate resin, and polystyrene resin. Examples of rubber materials include styrene-butadiene rubber (SBR), ethylene propylene rubber (EPR), and silicone rubber. The adherend may also be a foamed organic material. Examples of inorganic materials that can be used as the adherend include glass, cement, ceramic, and metal materials. The adherend may also be a fiber-reinforced plastic (FRP), a composite material made of fibers and the aforementioned plastic materials. The plastic material in the fiber-reinforced resin is at least one selected from the group consisting of polypropylene resin, polyethylene resin, polyurethane resin, acrylonitrile-butadiene-styrene copolymer resin (ABS resin), polycarbonate resin (PC resin), polyamide resin (such as nylon 6 and nylon 66), polyester resin (such as polyethylene terephthalate (PET resin) and polybutylene terephthalate resin (PBT resin)), polyacetal resin (POM resin), polymethyl methacrylate resin, and polystyrene resin. Examples of fibers in the fiber-reinforced resin include glass fiber, Kevlar fiber, and carbon fiber. When a plurality of adherends are bonded together using the adhesive for high-frequency dielectric heating according to this embodiment, the adherends may be made of the same material or different materials. The high-frequency dielectric heating adhesive according to this embodiment can be suitably used for bonding to glass adherends. When bonding multiple adherends together, as long as at least one of the adherends is made of glass, the high-frequency dielectric heating adhesive according to this embodiment can firmly bond to the glass adherend. The shape of the adherend is not particularly limited, but it preferably has a surface to which the high-frequency dielectric heating adhesive can be attached, and is preferably in the form of a sheet or plate. When multiple adherends are to be bonded together, the shapes and dimensions of the adherends may be the same or different.

[0102] [Adhesion method] The bonding method according to this embodiment is a bonding method that uses the high-frequency dielectric heating adhesive according to this embodiment. As an example of the bonding method according to this embodiment, a high-frequency dielectric heating adhesive sheet consisting of a single adhesive layer is used to bond a first adherend and a second adherend, but the present invention is not limited to this embodiment. The material of the second adherend is also not particularly limited.

[0103] The bonding method according to one aspect of this embodiment includes the following steps P1 and P2.

[0104] ·Process P1 Step P1 is a step of sandwiching the high-frequency dielectric heating adhesive sheet according to this embodiment between a first adherend and a second adherend. In step P1, the first adherend, made of glass, is brought into contact with the first surface of the high-frequency dielectric heating adhesive sheet. Also, in step P1, the second adherend is brought into contact with the second surface of the high-frequency dielectric heating adhesive sheet.

[0105] The high-frequency dielectric heating adhesive sheet may be sandwiched between the first and second adherends so as to bond them together. The high-frequency dielectric heating adhesive sheet may be sandwiched between the first and second adherends in a portion, multiple locations, or the entire surface. To improve the adhesive strength between the first and second adherends, it is preferable to sandwich the high-frequency dielectric heating adhesive sheet over the entire adhesive surface between the first and second adherends. Another example of sandwiching the high-frequency dielectric heating adhesive sheet over a portion between the first and second adherends is to arrange the high-frequency dielectric heating adhesive sheet in a frame shape along the periphery of the adhesive surface between the first and second adherends and sandwich it between the first and second adherends. Arranging the high-frequency dielectric heating adhesive sheet in this frame shape improves adhesive strength between the first and second adherends and reduces the weight of the bonded body compared to when the high-frequency dielectric heating adhesive sheet is arranged over the entire adhesive surface. In addition, according to one embodiment in which a high-frequency dielectric heating adhesive sheet is sandwiched between a portion of the first adherend and a second adherend, the size of the high-frequency dielectric heating adhesive sheet used can be reduced, thereby shortening the high-frequency dielectric heating treatment time compared to when the high-frequency dielectric heating adhesive sheet is placed over the entire adhesive surface.

[0106] ·Process P2 Step P2 is a step of applying a high-frequency electric field of 3 MHz or more and 300 MHz or less to the high-frequency dielectric heating adhesive sheet sandwiched between the first adherend and the second adherend in step P1, thereby bonding the first adherend and the second adherend with the high-frequency dielectric heating adhesive sheet. For example, a high-frequency electric field can be applied to a high-frequency dielectric heating adhesive sheet by using a dielectric heating bonding device. In this specification, the "dielectric heating device" may also be referred to as a "dielectric heating bonding device" or a "high-frequency dielectric heating device."

[0107] FIG. 2 shows a schematic diagram illustrating a high-frequency dielectric heating treatment using the high-frequency dielectric heating adhesive sheet and dielectric heating device according to this embodiment.

[0108] (Dielectric heating bonding device) FIG. 2 shows a schematic diagram of a dielectric heating bonding apparatus 50. The dielectric heating bonding device 50 includes a first high-frequency electric field applying electrode 51 , a second high-frequency electric field applying electrode 52 , and a high-frequency power supply 53 . The first high-frequency electric field applying electrode 51 and the second high-frequency electric field applying electrode 52 are arranged opposite to each other. The first high-frequency electric field applying electrode 51 and the second high-frequency electric field applying electrode 52 have a pressing mechanism. This pressing mechanism allows the first adherend 110, the high-frequency dielectric heating adhesive sheet 1A, and the second adherend 120 to be pressurized between the first high-frequency electric field applying electrode 51 and the second high-frequency electric field applying electrode 52.

[0109] When the first high-frequency electric field applying electrode 51 and the second high-frequency electric field applying electrode 52 form a pair of parallel plate electrodes, this electrode arrangement is sometimes called a parallel plate type. It is also preferable to use a parallel-plate type high-frequency dielectric heating device to apply the high-frequency electric field.With a parallel-plate type high-frequency dielectric heating device, the high-frequency electric field penetrates the high-frequency dielectric heating adhesive sheet located between the electrodes, so the entire high-frequency dielectric heating adhesive sheet can be heated and the adherend and the high-frequency dielectric heating adhesive sheet can be bonded in a short time.

[0110] A high frequency power supply 53 is connected to each of the first high frequency electric field applying electrode 51 and the second high frequency electric field applying electrode 52 to apply a high frequency electric field of, for example, about 13.56 MHz, about 27.12 MHz, or about 40.68 MHz. As shown in Figure 2, the dielectric heating bonding apparatus 50 performs a dielectric heating process via a high-frequency dielectric heating adhesive sheet 1A sandwiched between a first adherend 110 and a second adherend 120. In addition to the dielectric heating process, the dielectric heating bonding apparatus 50 also bonds the first adherend 110 and the second adherend 120 by a pressure process using a first high-frequency electric field application electrode 51 and a second high-frequency electric field application electrode 52. The first adherend 110 and the second adherend 120 may be bonded without the pressure process, for example, by pressing only with the weight of the adhesive sheet or the adherend. The first adherend 110 and the second adherend 120 may also be bonded without the pressure process.

[0111] When a high-frequency electric field is applied between the first high-frequency electric field application electrode 51 and the second high-frequency electric field application electrode 52, the dielectric filler (not shown) dispersed in the adhesive component of the high-frequency dielectric heating adhesive sheet 1A absorbs the high-frequency energy. The dielectric filler functions as a heat source, and the heat generated by the dielectric filler melts the thermoplastic resin component, ultimately resulting in a strong bond between the first adherend 110 and the second adherend 120, even with a short processing time.

[0112] The first high-frequency electric field applying electrode 51 and the second high-frequency electric field applying electrode 52 have a pressing mechanism and therefore function as a pressing device. Therefore, the first adherend 110 and the second adherend 120 can be more firmly bonded together by the compression direction pressure applied by the first high-frequency electric field applying electrode 51 and the second high-frequency electric field applying electrode 52 and the heat melting of the high-frequency dielectric heating adhesive sheet 1A.

[0113] (High frequency dielectric heating bonding conditions) The high-frequency dielectric heating bonding conditions can be changed as appropriate, but the following conditions are preferred.

[0114] The output of the high frequency electric field is preferably 10 W or more, more preferably 30 W or more, even more preferably 50 W or more, and even more preferably 80 W or more. The output of the high frequency electric field is preferably 50,000 W or less, more preferably 20,000 W or less, even more preferably 15,000 W or less, even more preferably 10,000 W or less, and even more preferably 1,000 W or less. If the output of the high frequency electric field is 10 W or more, the problem of the temperature not rising easily during the dielectric heating process can be prevented, and good adhesive strength can be easily obtained. If the output of the high frequency electric field is 50,000 W or less, it is easy to prevent the problem of temperature control becoming difficult during dielectric heating treatment.

[0115] The application time of the high frequency electric field is preferably 1 second or more. The application time of the high frequency electric field is preferably 300 seconds or less, more preferably 240 seconds or less, even more preferably 180 seconds or less, even more preferably 120 seconds or less, and even more preferably 100 seconds or less. If the application time of the high frequency electric field is 1 second or more, the problem of the temperature not rising easily during the dielectric heating process can be prevented, and good adhesive strength can be easily obtained. If the application time of the high-frequency electric field is 300 seconds or less, it is easy to prevent problems such as a decrease in the production efficiency of the bonded body in which a first adherend and a second adherend are bonded, an increase in production costs, and thermal deterioration of the adherends.

[0116] The frequency of the applied high frequency electric field is preferably 1 kHz or higher, more preferably 1 MHz or higher, even more preferably 5 MHz or higher, and even more preferably 10 MHz or higher. The frequency of the applied high-frequency electric field is preferably 300 MHz or less, more preferably 100 MHz or less, even more preferably 80 MHz or less, and even more preferably 50 MHz or less. Specifically, the industrial frequency bands of 13.56 MHz, 27.12 MHz, and 40.68 MHz assigned by the International Telecommunication Union are also used in the high-frequency dielectric heating bonding method (bonding method) of this embodiment.

[0117] (Effects of this embodiment) The high-frequency dielectric heating adhesive according to this embodiment can bond to glass with high adhesive strength even with little energy consumption. Furthermore, the high-frequency dielectric heating adhesive according to this embodiment is an adhesive that does not easily lose adhesive strength over time and has excellent long-term storage properties.

[0118] The high-frequency dielectric heating adhesive according to this embodiment has superior water resistance and moisture resistance compared to general pressure-sensitive adhesives.

[0119] The high-frequency dielectric heating adhesive according to this embodiment is heated by the application of a high-frequency electric field, which causes the high-frequency dielectric heating adhesive to be heated locally, making it easier to prevent the entire adherend from melting when being bonded to the adherend.

[0120] According to the bonding method using the high-frequency dielectric heating adhesive of this embodiment, it is possible to locally heat only predetermined locations from the outside using a dielectric heating bonding device. Therefore, the bonding method using the high-frequency dielectric heating adhesive of this embodiment is effective even when the adherend is a large and complex three-dimensional structure or a thick and complex three-dimensional structure, etc., and even when high dimensional accuracy is required.

[0121] [Modifications of the embodiment] The present invention is not limited to the above-described embodiment, and may include modifications and improvements within the scope of achieving the object of the present invention.

[0122] The high-frequency dielectric heating adhesive sheet may have an adhesive portion. By having an adhesive portion, it is possible to prevent misalignment when sandwiching the high-frequency dielectric heating adhesive sheet between two adherends and to position it accurately. The adhesive portion may be provided on one side of the high-frequency dielectric heating adhesive sheet or on both sides. The adhesive portion may also be provided partially on one side of the high-frequency dielectric heating adhesive sheet. Even if the high-frequency dielectric heating adhesive sheet does not have an adhesive portion, it can firmly bond a first adherend and a second adherend.

[0123] The high-frequency dielectric heating process is not limited to the dielectric heating bonding device with electrodes arranged opposite to each other as described in the above embodiment, and a grid-type high-frequency dielectric heating device may also be used. A grid-type high-frequency dielectric heating device has a grid electrode in which electrodes of a first polarity and electrodes of a second polarity opposite to the first polarity are alternately arranged at regular intervals on the same plane. For example, when producing a bonded body in which the end of a first adherend and the end of a second adherend are overlapped and bonded, a grid electrode type high-frequency dielectric heating device is placed on the first adherend side or the second adherend side to apply a high-frequency electric field.

[0124] When a first adherend and a second adherend are bonded using a grid electrode type high-frequency dielectric heating device, a first grid electrode may be placed on the first adherend side and a second grid electrode may be placed on the second adherend side, and the first adherend, the high-frequency dielectric heating adhesive, and the second adherend may be sandwiched between the first grid electrode and the second grid electrode and a high-frequency electric field may be applied simultaneously.

[0125] When a first adherend and a second adherend are bonded using a grid electrode type high-frequency dielectric heating device, a grid electrode may be placed on one side of each of the first adherend and the second adherend, a high-frequency electric field may be applied, and then a grid electrode may be placed on the other side of each of the first adherend and the second adherend, and a high-frequency electric field may be applied.

[0126] It is also preferable to use a grid electrode type high-frequency dielectric heating device to apply the high-frequency electric field. By using a grid electrode type high-frequency dielectric heating device, the adherends can be bonded together by dielectrically heating the surface side of the first and second adherends, for example, from the side of the adherend closest to the high-frequency dielectric heating adhesive, without being affected by the thickness of the first and second adherends. Furthermore, by using a grid electrode type high-frequency dielectric heating device, energy savings can be achieved in the production of bonded bodies.

[0127] For the sake of simplicity, the drawings show an example in which a dielectric heating bonding device is used in which electrodes are arranged opposite each other. [Example]

[0128] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0129] [Preparation of adhesive for high frequency dielectric heating] (Examples 1 to 5 and Comparative Examples 1 to 2) The materials shown in Table 1 were premixed. The premixed materials were fed into the hopper of a 30 mm diameter twin-screw extruder, and the cylinder temperature was set to 180°C or higher and 200°C or lower, and the die temperature was set to 200°C, where the premixed materials were melt-kneaded. The melt-kneaded materials were cooled and then cut to produce granular pellets. The produced granular pellets were then fed into the hopper of a single-screw extruder equipped with a T-die. A film-like melt-kneaded product was extruded from the T-die under conditions of a cylinder temperature of 200°C and a die temperature of 200°C, and cooled on a cooling roll to produce 400 μm-thick sheet-like high-frequency dielectric heating adhesives (high-frequency dielectric heating adhesive sheets) according to Examples 1 to 5 and Comparative Examples 1 and 2.

[0130] The thermoplastic resins and fillers shown in Table 1 are described as follows. Silane-modified PP: Silane-modified polypropylene, manufactured by Mitsubishi Chemical Corporation, product name "Linkron PM700N" Silane-modified PE: Silane-modified polyethylene, manufactured by Mitsubishi Chemical Corporation, product name "Linkron SS732N" m-PP: Maleic anhydride modified polypropylene, manufactured by Mitsubishi Chemical Corporation, product name "Modic P565" PP: Polypropylene, manufactured by Prime Polymer Co., Ltd., product name: Prime Polypro F-744NP m-PE: Maleic anhydride modified polyethylene, manufactured by Mitsubishi Chemical Corporation, product name "Modic M545" Zinc oxide (ZnO): Zinc oxide with a volume average particle size of 11 μm. Manufactured by Sakai Chemical Industry Co., Ltd., product name "LP-ZINC11"

[0131] (MFR: Melt flow rate) The MFR of the thermoplastic resin at 190°C was measured in accordance with JIS K 7210-1:2014 using a descending flow tester (manufactured by Shimadzu Corporation, model number "CFT-100D"). When a mixture of multiple thermoplastic resins was used, the multiple resins were kneaded in a twin-screw kneader in the ratios shown in Table 1 to prepare mixed resin pellets, and the MFR of the mixed resin pellets was measured in the same manner as above.

[0132] (Volume average particle size of dielectric filler) The particle size distribution of the dielectric filler was measured by laser diffraction / scattering. The volume average particle diameter was calculated from the particle size distribution measurement results in accordance with JIS Z 8819-2:2001. The calculated volume average particle diameter of zinc oxide (ZnO) was 11 μm.

[0133] [Evaluation of high frequency dielectric heating adhesive sheet] The high frequency dielectric heating adhesive sheet was evaluated as follows, and the evaluation results are shown in Table 1.

[0134] (Adhesive strength (tensile shear strength)) As one index for evaluating high frequency adhesiveness, adhesive strength (tensile shear strength) was evaluated. The high-frequency dielectric heating adhesive sheet thus prepared was cut into a size of 25 mm x 12.5 mm. The cut high-frequency dielectric heating adhesive sheet was placed between a pair of adherends (first adherend and second adherend) made of soda lime glass (25 mm x 100 mm x 3 mm (thickness)) so that it coincided with the overlapping portions of the adherends. After being placed in this manner, the pair of adherends and the high-frequency dielectric heating adhesive sheet were fixed between the electrodes of a high-frequency dielectric heating device (manufactured by Yamamoto Vinita Co., Ltd., product name "YRP-400T-A"). The area of ​​the pair of electrodes of the high-frequency dielectric heating device was 800 mm2 each. 2 The electrodes were placed so as to cover the overlapping portion of the adherend (soda lime glass) (40mm x 20mm). In this fixed state, a high frequency electric field was applied under the following high frequency application conditions to bond the high frequency dielectric heating adhesive sheet to the adherend, producing a test piece for evaluating adhesive strength. In addition, the high-frequency dielectric heating adhesive sheet thus prepared was separately stored under high temperature and high humidity conditions for a long period of time (storage for one week under conditions of 50°C and 95% RH), and then test pieces for adhesive strength evaluation were prepared in the same manner as above.

[0135] High frequency application conditions Frequency: 40.68MHz Output: 150W Application time: 20 seconds Pressing pressure: 0.5 MPa The pressure during application of high frequency is the pressure applied to the joint between the first adherend and the second adherend.

[0136] The test specimens prepared using the high-frequency dielectric heating adhesive sheet before long-term storage under high-temperature, high-humidity conditions were used as test specimens before the accelerated test, and the test specimens prepared using the high-frequency dielectric heating adhesive sheet after long-term storage were used as test specimens after the accelerated test. These test specimens were used to measure the tensile shear strength (unit: MPa) as adhesive strength. A universal tensile testing machine (Instron Corporation, product name "Instron 5581") was used to measure the tensile shear strength. The tensile speed for measuring the tensile shear strength was 10 mm / min. ">4.0" in the table indicates that the tensile shear strength was greater than 4.0 MPa. The tensile shear strength was measured in accordance with JIS K 6850:1999.

[0137] [Table 1]

[0138] The high-frequency dielectric heating adhesive sheets of Examples 1 to 5 contain a silane-modified thermoplastic resin and a non-silane-modified thermoplastic resin as thermoplastic resins, and therefore can bond glass adherends together with high adhesive strength even with little energy consumption, and have high tensile shear strength before the accelerated test and the same or higher tensile shear strength after the accelerated test, so that the adhesive strength does not decrease over time and the adhesive sheets have good long-term storage properties. The high-frequency dielectric heating adhesive sheet of Comparative Example 1 contained a silane-modified thermoplastic resin as the thermoplastic resin, and therefore had a high tensile shear strength before the accelerated test. However, the high-frequency dielectric heating adhesive sheet of Comparative Example 1 did not contain a non-silane-modified thermoplastic resin, and therefore the tensile shear strength after the accelerated test was significantly reduced. Thus, the high-frequency dielectric heating adhesive sheet of Comparative Example 1 was an adhesive sheet whose adhesive strength was prone to decrease over time and had poor long-term storage stability. The high-frequency dielectric heating adhesive sheet of Comparative Example 2 did not adhere to glass because it did not contain a silane-modified thermoplastic resin as the thermoplastic resin. [Explanation of symbols]

[0139] 10...adhesive layer (first adhesive layer), 10D...first part, 10E...first part, 10F...first part, 11...first surface, 12...second surface, 110...first adherend, 120...second adherend, 1A...high frequency dielectric heating adhesive sheet, 1B...high frequency dielectric heating adhesive sheet, 1C...high frequency dielectric heating adhesive sheet, 1D...molded body, 1E...molded body, 1F...molded body, 20...adhesive layer (second adhesive layer), 20D...second part, 20E...second part, 20F...second part, 21...second surface, 30...substrate, 40...intermediate layer, 50...dielectric heating bonding device, 51...first high frequency electric field application electrode, 52...second high frequency electric field application electrode, 53...high frequency power supply.

Claims

1. A high-frequency dielectric heating adhesive, The high-frequency dielectric heating adhesive contains at least a thermoplastic resin (A) and a dielectric material that generates heat upon application of a high-frequency electric field in a frequency range of 3 MHz or more and 300 MHz or less, the thermoplastic resin (A) contains at least a first thermoplastic resin (A1) and a second thermoplastic resin (A2), the volume content of the first thermoplastic resin (A1) in the thermoplastic resin (A) is 15% by volume or more and 80% by volume or less; the volume content of the second thermoplastic resin (A2) in the thermoplastic resin (A) is 20% by volume or more and 85% by volume or less; the volume content of the dielectric material in the high-frequency dielectric heating adhesive is 5% by volume or more and 40% by volume or less, the first thermoplastic resin (A1) is a silane-modified thermoplastic resin, the second thermoplastic resin (A2) is a non-silane-modified thermoplastic resin, The dielectric material is a dielectric filler (B), The dielectric filler (B) is zinc oxide, The total content of the thermoplastic resin (A) and the dielectric filler (B) in the high-frequency dielectric heating adhesive is 80 mass% or more. Adhesive for high frequency dielectric heating.

2. The high-frequency dielectric heating adhesive according to claim 1, The first thermoplastic resin (A1) is a silane-modified polyolefin resin. Adhesive for high frequency dielectric heating.

3. The high-frequency dielectric heating adhesive according to claim 1 or 2, The second thermoplastic resin (A2) is a non-silane-modified polyolefin resin. Adhesive for high frequency dielectric heating.

4. The adhesive for high-frequency dielectric heating according to any one of claims 1 to 3, The second thermoplastic resin (A2) has a polar moiety. Adhesive for high frequency dielectric heating.

5. The high-frequency dielectric heating adhesive according to claim 4, The polar moiety of the second thermoplastic resin (A2) is an acidic moiety. Adhesive for high frequency dielectric heating.

6. The high-frequency dielectric heating adhesive according to claim 5, the acidic moiety of the second thermoplastic resin (A2) is an acid anhydride structure; Adhesive for high frequency dielectric heating.

7. The adhesive for high-frequency dielectric heating according to any one of claims 1 to 6, The repeating unit contained most abundantly in the polymer of the first thermoplastic resin (A1) is ethylene or propylene. Adhesive for high frequency dielectric heating.

8. The adhesive for high-frequency dielectric heating according to any one of claims 1 to 7, The repeating unit contained most abundantly in the polymer of the second thermoplastic resin (A2) is ethylene or propylene. Adhesive for high frequency dielectric heating.

9. The adhesive for high-frequency dielectric heating according to any one of claims 1 to 8, the repeating unit contained most abundantly in the polymer of the first thermoplastic resin (A1) is the same as the repeating unit contained most abundantly in the polymer of the second thermoplastic resin (A2); Adhesive for high frequency dielectric heating.

10. The high-frequency dielectric heating adhesive according to any one of claims 1 to 9, The MFR of the thermoplastic resin (A) at 190°C is 2 g / 10 min or more and 50 g / 10 min or less. Adhesive for high frequency dielectric heating.

11. The adhesive for high-frequency dielectric heating according to any one of claims 1 to 10, The total content of the thermoplastic resin (A) and the dielectric filler (B) in the high-frequency dielectric heating adhesive is 90 mass% or more. Adhesive for high frequency dielectric heating.

12. The adhesive for high-frequency dielectric heating according to any one of claims 1 to 11, The volume average particle diameter of the dielectric filler (B) is 1 μm or more and 30 μm or less, The volume average particle diameter is a volume average particle diameter calculated from the particle size distribution measurement results of the dielectric filler (B) by a laser diffraction / scattering method in accordance with JIS Z 8819-2:2001. Adhesive for high frequency dielectric heating.

13. The high-frequency dielectric heating adhesive is an adhesive sheet. The adhesive for high-frequency dielectric heating according to any one of claims 1 to 12.

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