Next method

Abstract

To provide an adhesion method that can shorten an application time of a high-frequency electric field and improve adhesive strength even when the field is applied for a short time.SOLUTION: A method for bonding an adherend by means of a high-frequency dielectric heating adhesive sheet 1A containing a thermoplastic resin (A) includes: a first process of applying a high-frequency electric field of applied output V1 per unit area to the high-frequency dielectric heating adhesive sheet 1A; and a second process of applying a high-frequency electric field of applied output V2 per unit area to the high-frequency dielectric heating adhesive sheet 1A after the first process. The applied output V1 per unit area of the first process and the applied output V2 per unit area of the second process satisfy a condition expressed in a following formula (number 1). V1>V2...(number 1)SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an adhesion method.

Background Art

[0002] In recent years, as a method for adhering adherends that are generally difficult to adhere to each other, for example, an adhesive obtained by blending a heat-generating material in a predetermined resin is interposed between the adherends, and dielectric heat treatment, induction heat treatment, ultrasonic welding treatment, or laser welding treatment is performed. A method has been proposed.

[0003] For example, Patent Document 1 describes a high-frequency dielectric heating adhesive sheet for adhering a plurality of adherends made of the same material or different materials. This high-frequency dielectric heating adhesive sheet contains a predetermined thermoplastic resin blended at a predetermined ratio and a dielectric filler.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] According to Patent Document 1, the application time of the high-frequency electric field can be shortened, but from the viewpoint of production efficiency, it is required to further shorten the application time.

[0006] An object of the present invention is to provide an adhesion method capable of shortening the application time of a high-frequency electric field and improving the adhesion strength even with a short application time.

Means for Solving the Problems

[0007] According to one aspect of the present invention, there is provided a method for adhering an adherend using a high-frequency dielectric heating adhesive sheet, wherein the high-frequency dielectric heating adhesive sheet contains a thermoplastic resin (A), and the method includes: a first step of applying a high-frequency electric field with an applied output V1 per unit area to the high-frequency dielectric heating adhesive sheet; and a second step of applying a high-frequency electric field with an applied output V2 per unit area to the high-frequency dielectric heating adhesive sheet after the first step, and the applied output V1 per unit area in the first step and the applied output V2 per unit area in the second step satisfy the condition represented by the following mathematical formula (Formula 1). V1 > V2…(Formula 1)

[0008] In the adhesion method according to one aspect of the present invention, it is preferable that the applied output V1 per unit area in the first step and the applied output V2 per unit area in the second step satisfy the condition represented by the following mathematical formula (Formula 1-1). 0.8 × V1 ≥ V2…(Formula 1-1)

[0009] In the adhesion method according to one aspect of the present invention, the applied output V1 per unit area in the first step is preferably 0.18 W / mm 2 or more and 2.00 W / mm 2 or less.

[0010] In the adhesion method according to one aspect of the present invention, the application time T1 in the first step is preferably 1 second or more and less than 25 seconds.

[0011] In the adhesion method according to one aspect of the present invention, the applied output V2 per unit area in the second step is preferably 0.09 W / mm 2 or more and 0.30 W / mm 2 or less.

[0012] In the adhesion method according to one aspect of the present invention, the application time T2 in the second step is preferably 5 seconds or more.

[0013] In the bonding method according to one aspect of the present invention, it is preferable that the application time T1 in the first step and the application time T2 in the second step satisfy the condition represented by the following mathematical formula (Formula 2). (T1 + T2) < 60 seconds... (Formula 2)

[0014] According to one aspect of the present invention, there is provided a method for bonding an adherend with a high-frequency dielectric heating adhesive sheet, wherein the high-frequency dielectric heating adhesive sheet contains a thermoplastic resin (A), and a first step of applying a high-frequency electric field with an energy J1 per unit area to the high-frequency dielectric heating adhesive sheet, and a second step of applying a high-frequency electric field with an energy J2 per unit area to the high-frequency dielectric heating adhesive sheet after the first step, and an adhesive method is provided in which the energy J1 per unit area applied in the first step and the energy J2 per unit area applied in the second step satisfy the condition represented by the following mathematical formula (Formula 3). J1 > 0.75 × J2... (Formula 3)

[0015] In the bonding method according to one aspect of the present invention, it is preferable that the energy J1 per unit area applied in the first step and the energy J2 per unit area applied in the second step satisfy the condition represented by the following mathematical formula (Formula 3-1). 0.9 > J1 / (J1 + J2) > 0.4... (Formula 3-1)

[0016] In the bonding method according to one aspect of the present invention, the thermoplastic resin (A) is preferably a polyolefin resin.

[0017] In the bonding method according to one aspect of the present invention, it is preferable that the high-frequency dielectric heating adhesive sheet further contains a dielectric filler (B) that generates heat by applying a high-frequency electric field.

[0018] In the bonding method 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.

Advantages of the Invention

[0019] According to one aspect of the present invention, it is possible to provide an adhesion method capable of shortening the application time of a high-frequency electric field and improving the adhesion strength even with a short application time.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0021] [First Embodiment] [Adhesion Method] The adhesion method according to the present embodiment is a method of adhering an adherend with a high-frequency dielectric heating adhesive sheet. This high-frequency dielectric heating adhesive sheet contains a thermoplastic resin (A). The adhesion method according to the present embodiment includes a first step of applying a high-frequency electric field with an applied output V1 per unit area to the high-frequency dielectric heating adhesive sheet, and a second step of applying a high-frequency electric field with an applied output V2 per unit area to the high-frequency dielectric heating adhesive sheet after the first step, and the applied output V1 per unit area in the first step and the applied output V2 per unit area in the second step satisfy the condition represented by the following mathematical formula (Formula 1). Note that the high-frequency electric field is an electric field whose direction reverses at a high frequency. V1 > V2…(Formula 1)

[0022] Hereinafter, as an example of the adhesion method according to the present embodiment, a mode of adhering a first adherend and a second adherend using a high-frequency dielectric heating adhesive sheet composed of a single adhesive layer will be described. However, the present invention is not limited to this mode. The materials of the first adherend and the second adherend are also not particularly limited.

[0023] The adhesion method according to the present embodiment includes the following first step and second step. In the first step and the second step, a high-frequency electric field is applied to a high-frequency dielectric heating adhesive sheet sandwiched between a first adherend and a second adherend to bond the first adherend and the second adherend with the high-frequency dielectric heating adhesive sheet. Normally, the step of applying a high-frequency electric field is not divided into two steps. In contrast, in the present embodiment, by dividing it into two specific steps, namely the first step and the second step, the degree of melting and heating of the resin in the high-frequency dielectric heating adhesive sheet is adjusted. Accordingly, it is presumed that according to the present embodiment, the adhesive strength can be improved even with a short application time.

[0024] In the first step, a high-frequency electric field with an applied output V1 per unit area is applied to the high-frequency dielectric heating adhesive sheet. In the second step, a high-frequency electric field with an applied output V2 per unit area is applied to the high-frequency dielectric heating adhesive sheet after the first step.

[0025] It is necessary that the applied output V1 per unit area in the first step and the applied output V2 per unit area in the second step satisfy the condition represented by the following mathematical formula (Formula 1). V1 > V2…(Formula 1) When the condition represented by the above mathematical formula (Formula 1) is not satisfied, it is not possible to improve the adhesive strength while shortening the application time of the high-frequency electric field.

[0026] In the present embodiment, it is preferable that the applied output V1 per unit area in the first step and the applied output V2 per unit area in the second step satisfy the condition represented by the following mathematical formula (Formula 1-1). 0.8×V1 ≥ V2…(Formula 1-1) When the condition represented by the above mathematical formula (Formula 1-1) is satisfied, it is easy to improve the adhesive strength. From the same perspective, the upper limit of the applied output V2 per unit area in the second step is preferably 0.75 times or less the value of the applied output V1 per unit area in the first step, more preferably 0.7 times or less the value of the applied output V1 per unit area in the first step, even more preferably 0.65 times or less the value of the applied output V1 per unit area in the first step, and particularly preferably 0.6 times or less the value of the applied output V1 per unit area in the first step. From the perspective of shortening the application time, the lower limit of the applied output V2 per unit area in the second step is preferably 0.1 times or more the value of the applied output V1 per unit area in the first step, more preferably 0.2 times or more the value of the applied output V1 per unit area in the first step, even more preferably 0.3 times or more the value of the applied output V1 per unit area in the first step, and particularly preferably 0.4 times or more the value of the applied output V1 per unit area in the first step.

[0027] The applied output V1 per unit area in the first step is preferably 0.18 W / mm 2 or more, more preferably 0.20 W / mm 2 or more, even more preferably 0.22 W / mm 2 or more. The applied output V1 per unit area in the first step is preferably 2.00 W / mm 2 or less, more preferably 1.75 W / mm 2 or less, even more preferably 1.50 W / mm 2 or less, even more preferably 1.25 W / mm 2 or less, even more preferably 1.00 W / mm 2 or less, even more preferably 0.75 W / mm 2 or less, even more preferably 0.5 W / mm 2 or less is particularly preferred. If the applied output V1 per unit area in the first step is 0.18 W / mm 2 or more, the problem that the resin is unlikely to be in a molten state can be prevented, so it is easy to obtain good adhesion. If the applied output V1 per unit area in the first step is 2.00 W / mm2 If it is as follows, it is possible to prevent the problem that the resin foams and the adhesive strength decreases, so that a good adhesive force can be easily obtained.

[0028] The application time T1 in the first step is preferably 1 second or more, more preferably 3 seconds or more, still more preferably 5 seconds or more, even more preferably 7 seconds or more, and particularly preferably 10 seconds or more. The application time T1 in the first step is preferably less than 25 seconds, more preferably 24 seconds or less, and still more preferably 20 seconds or less. If the application time T1 in the first step is 1 second or more, it is possible to prevent the problem that the temperature hardly rises during the dielectric heat treatment, so that a good adhesive force can be easily obtained. If the application time T1 in the first step is less than 25 seconds, the application time of the high-frequency electric field can be further shortened.

[0029] The applied output V2 per unit area in the second step is preferably 0.09 W / mm 2 or more, more preferably 0.10 W / mm 2 or more, still more preferably 0.11 W / mm 2 or more. The applied output V2 per unit area in the second step is preferably 0.30 W / mm 2 or less, more preferably 0.25 W / mm 2 or less, still more preferably 0.20 W / mm 2 or less, particularly preferably 0.18 W / mm 2 or less. If the applied output V2 per unit area in the second step is 0.09 W / mm 2 or more, the processing temperature after the first step can be maintained, so that a good adhesive force can be easily obtained. If the applied output V2 per unit area in the second step is 0.30 W / mm 2 or less, it is possible to prevent the problem that the resin foams and the adhesive strength decreases, so that a good adhesive force can be easily obtained.

[0030] The application time T2 of the second step is preferably 5 seconds or more, more preferably 7 seconds or more, still more preferably 9 seconds or more, and particularly preferably 10 seconds or more. The application time T2 of the second step is preferably less than 60 seconds, more preferably less than 50 seconds, still more preferably less than 40 seconds, and particularly preferably less than 30 seconds. If the application time T2 of the second step is 5 seconds or more, the time for maintaining the processing temperature after the first step can be ensured, so that good adhesion can be easily obtained. If the application time T2 of the second step is less than 60 seconds, the application time of the high-frequency electric field can be further shortened.

[0031] In this embodiment, it is preferable that the application time T1 of the first step and the application time T2 of the second step satisfy the conditions represented by the following mathematical formula (Formula 2). (T1 + T2) < 60 seconds... (Formula 2) When the conditions represented by the above mathematical formula (Formula 2) are satisfied, the application time of the high-frequency electric field can be further shortened. Also, from the same viewpoint, the total (T1 + T2) of the application time T1 and the application time T2 is more preferably 50 seconds or less, still more preferably 40 seconds or less, and particularly preferably 30 seconds or less.

[0032] In the first step and the second step, the frequency of the applied high-frequency electric field is preferably 1 kHz or more, more preferably 1 MHz or more, still more preferably 5 MHz or more, and even more preferably 10 MHz or more. The frequency of the applied high-frequency electric field is preferably 300 MHz or less, more preferably 100 MHz or less, still more preferably 80 MHz or less, and even more preferably 50 MHz or less. Specifically, the industrial frequency bands 13.56 MHz, 27.12 MHz, or 40.68 MHz assigned by the International Telecommunication Union are also used in the adhesion method according to this embodiment.

[0033] The adhesion method according to this embodiment may include step P1 before the aforementioned first step and second step.

[0034] · Step P1 Step P1 is a step of disposing the high-frequency dielectric heating adhesive sheet according to this embodiment between the first adherend and the second adherend. In step P1, the first adherend 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.

[0035] It is preferable to sandwich the high-frequency dielectric heating adhesive sheet between the first adherend and the second adherend so that the first adherend and the second adherend can be adhered. The high-frequency dielectric heating adhesive sheet may be sandwiched at a part, at a plurality of locations, or over the entire surface between the first adherend and the second adherend. From the viewpoint of improving the adhesion strength between the first adherend and the second adherend, it is preferable to sandwich the high-frequency dielectric heating adhesive sheet over the entire adhesion surface between the first adherend and the second adherend. Also, as one aspect of sandwiching the high-frequency dielectric heating adhesive sheet at a part between the first adherend and the second adherend, there is an aspect of arranging the high-frequency dielectric heating adhesive sheet in a frame shape along the outer periphery of the adhesion surface between the first adherend and the second adherend and sandwiching it between the first adherend and the second adherend. By arranging the high-frequency dielectric heating adhesive sheet in a frame shape in this way, the adhesion strength between the first adherend and the second adherend can be obtained, and the weight of the joined body can be reduced compared to the case where the high-frequency dielectric heating adhesive sheet is arranged over the entire adhesion surface. Also, according to one aspect of sandwiching the high-frequency dielectric heating adhesive sheet at a part between the first adherend and the second adherend, the size of the high-frequency dielectric heating adhesive sheet to be used can be reduced, so the high-frequency dielectric heating treatment time can be shortened compared to the case where the high-frequency dielectric heating adhesive sheet is arranged over the entire adhesion surface.

[0036] (Adherend) The materials of the first adherend and the second adherend are not particularly limited. The material of the adherend may be any of an organic material and an inorganic material (including metal materials, etc.), or a composite material of an organic material and an inorganic material. Examples of the organic material as the material of the adherend include a plastic material and a rubber material. Examples of the plastic material include a polypropylene resin, a polyethylene resin, a polyurethane resin, an acrylonitrile-butadiene-styrene copolymer resin (ABS resin), a polycarbonate resin (PC resin), a polyamide resin (such as nylon 6 and nylon 66), a polyester resin (such as polyethylene terephthalate (PET resin) and polybutylene terephthalate resin (PBT resin)), a polyacetal resin (POM resin), a polymethyl methacrylate resin, and a polystyrene resin. Examples of the rubber material include styrene-butadiene rubber (SBR), ethylene propylene rubber (EPR), and silicone rubber. Further, the adherend may be a foam material of an organic material. Examples of the inorganic material as the material of the adherend include a glass material, a cement material, a ceramic material, and a metal material. Further, the adherend may be a fiber reinforced resin (Fiber Reinforced Plastics, FRP) which is a composite material of a fiber and the above-described plastic material. The plastic material in this fiber reinforced resin is at least one selected from the group consisting of, for example, a polypropylene resin, a polyethylene resin, a polyurethane resin, an acrylonitrile-butadiene-styrene copolymer resin (ABS resin), a polycarbonate resin (PC resin), a polyamide resin (such as nylon 6 and nylon 66), a polyester resin (such as polyethylene terephthalate (PET resin) and polybutylene terephthalate resin (PBT resin)), a polyacetal resin (POM resin), a polymethyl methacrylate resin, and a polystyrene resin. Examples of the fiber in the fiber reinforced resin include a glass fiber, a Kevlar fiber, and a carbon fiber. When a plurality of adherends are adhered to each other using the high-frequency dielectric heating adhesive sheet according to the present embodiment, the plurality of adherends may be of the same material as each other or of different materials. The high-frequency dielectric heating adhesive sheet according to this embodiment can be suitably used for adhesion to an adherend. The shape of the adherend is not particularly limited, but it preferably has a surface to which the high-frequency dielectric heating adhesive sheet can be bonded, and is preferably sheet-shaped or plate-shaped. When bonding a plurality of adherends to each other, the shapes and dimensions of these adherends may be the same or different from each other.

[0037] (Dielectric heating adhesive device) In the above-described first step and second step, for example, by using a dielectric heating adhesive device, a high-frequency electric field can be applied to the high-frequency dielectric heating adhesive sheet. FIG. 1 shows a schematic diagram for explaining a high-frequency dielectric heating process using the high-frequency dielectric heating adhesive sheet and the dielectric heating device according to this embodiment. FIG. 1 shows a schematic diagram of a dielectric heating adhesive device 50. The dielectric heating adhesive device 50 includes a first high-frequency electric field application electrode 51, a second high-frequency electric field application electrode 52, and a high-frequency power source 53. The first high-frequency electric field application electrode 51 and the second high-frequency electric field application electrode 52 are arranged to face each other. The first high-frequency electric field application electrode 51 and the second high-frequency electric field application electrode 52 have a pressing mechanism. By this pressing mechanism, the first adherend 110, the high-frequency dielectric heating adhesive sheet 1A, and the second adherend 120 can be pressure-treated between the first high-frequency electric field application electrode 51 and the second high-frequency electric field application electrode 52.

[0038] When the first high-frequency electric field application electrode 51 and the second high-frequency electric field application electrode 52 constitute a pair of parallel flat electrodes parallel to each other, such a form of electrode arrangement may be referred to as a parallel plate type. It is also preferable to use a parallel plate type high-frequency dielectric heating device for applying a high-frequency electric field. In the case of a parallel plate type high-frequency dielectric heating device, since the high-frequency penetrates the high-frequency dielectric heating adhesive sheet located between the electrodes, 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.

[0039] A high-frequency power supply 53 for applying a high-frequency electric field of, for example, about 13.56 MHz, about 27.12 MHz, or about 40.68 MHz is connected to each of the first high-frequency electric field application electrode 51 and the second high-frequency electric field application electrode 52. As shown in FIG. 1, the dielectric heating and bonding device 50 performs dielectric heat treatment through a high-frequency dielectric heating and bonding sheet 1A sandwiched between a first adherend 110 and a second adherend 120. Further, in addition to the dielectric heat treatment, the dielectric heating and bonding device 50 bonds the first adherend 110 and the second adherend 120 by a pressing treatment using the first high-frequency electric field application electrode 51 and the second high-frequency electric field application electrode 52.

[0040] 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 high-frequency dielectric heating and bonding sheet 1A absorbs high-frequency energy. Then, the thermoplastic resin component of the high-frequency dielectric heating and bonding sheet 1A melts, and finally, the first adherend 110 and the second adherend 120 can be firmly bonded.

[0041] Since the first high-frequency electric field application electrode 51 and the second high-frequency electric field application electrode 52 have a pressing mechanism, they also function as a pressing device. Therefore, by pressing in the compression direction by the first high-frequency electric field application electrode 51 and the second high-frequency electric field application electrode 52 and heating and melting the high-frequency dielectric heating and bonding sheet 1A, the first adherend 110 and the second adherend 120 can be bonded more firmly.

[0042] The bonded body according to the present embodiment includes a first adherend, a second adherend, and the high-frequency dielectric heating and bonding sheet according to the present embodiment. The first adherend and the second adherend are bonded by the high-frequency dielectric heating and bonding sheet. As an aspect of the bonded body according to the present embodiment, for example, as shown in FIG. 1, a bonded body including a first adherend 110, a high-frequency dielectric heating and bonding sheet 1A, and a second adherend 120 can be mentioned.

[0043] [High-frequency dielectric heating and bonding sheet] Next, the high-frequency dielectric heating adhesive sheet used in the adhesion method according to this embodiment will be described. The high-frequency dielectric heating adhesive sheet according to this embodiment has an adhesive layer. The adhesive layer contains a thermoplastic resin (A).

[0044] (Thermoplastic resin (A)) The type of the thermoplastic resin (A) is not particularly limited. From the viewpoints such as being easy to melt and having a predetermined heat resistance, the thermoplastic resin (A) is preferably at least one selected from the group consisting of polyolefin resins, styrene resins, polyacetal resins, polycarbonate resins, polyacrylic resins, polyamide resins, polyimide resins, polyvinyl acetate resins, phenoxy resins, and polyester resins. From the viewpoints of being inexpensive and having excellent moldability and mechanical strength, the thermoplastic resin (A) is preferably a polyolefin resin. In this specification, the polyolefin resin includes a polyolefin resin having a polar part and a polyolefin resin having no polar part, and when specifying the presence or absence of a polar part, it is described as a polyolefin resin having a polar part or a polyolefin resin having no polar part.

[0045] (Polyolefin resin) Examples of the polyolefin resin as the thermoplastic resin include resins composed of homopolymers such as polyethylene, polypropylene, polybutene, and polymethylpentene, and α-olefin resins composed of copolymers of monomers selected from the group consisting of ethylene, propylene, butene, hexene, octene, and 4-methylpentene. The polyolefin resin as the thermoplastic resin may be a single resin or a combination of two or more resins.

[0046] (Polyolefin resin having a polar part) The polar site in the polyolefin resin having a polar site is not particularly limited as long as it can impart polarity to the polyolefin resin. The polyolefin resin having a polar site is preferable because it exhibits high adhesive strength to an adherend. The thermoplastic resin may be a copolymer of an olefin monomer and a monomer having a polar site. Further, the thermoplastic resin may be a resin in which a polar site is introduced into an olefin polymer obtained by polymerization of an olefin monomer by modification such as an addition reaction.

[0047] The type of olefin monomer constituting the polyolefin resin having a polar site as a thermoplastic resin is not particularly limited. Examples of the olefin monomer include ethylene, propylene, butene, hexene, octene, 4-methyl-1-pentene, and the like. The olefin monomer may be used alone or in combination of two or more. From the viewpoint of excellent mechanical strength and stable adhesion characteristics, ethylene and polypropylene are preferable as the olefin monomer. The structural unit derived from olefin in the polyolefin resin having a polar site is preferably a structural unit derived from ethylene or propylene.

[0048] Examples of the polar site include a hydroxyl group, a carboxy group, a vinyl acetate structure, and an acid anhydride structure.

[0049] (Dielectric filler (B)) The high-frequency dielectric heating adhesive sheet according to the present embodiment preferably further includes a dielectric filler (B) 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 a frequency range of 3 MHz or more and 300 MHz or less is applied. The dielectric filler (B) is preferably a filler that generates heat when a high-frequency electric field such as a frequency of 13.56 MHz, 27.12 MHz, or 40.68 MHz is applied within the frequency range of 3 MHz or more and 300 MHz or less.

[0050] (Type) The dielectric filler (B) is preferably one kind alone or a combination of two or more kinds of inorganic materials having crystal water such as zinc oxide, silicon carbide (SiC), anatase titanium oxide, barium titanate, barium zirconate titanate, lead titanate, potassium niobate, rutile titanium oxide, hydrated aluminum silicate, hydrated aluminosilicate of an alkali metal, or inorganic materials having crystal water such as hydrated aluminosilicate of an alkaline earth metal.

[0051] The dielectric filler (B) preferably contains at least any one selected from the group consisting of zinc oxide, silicon carbide, barium titanate, and titanium oxide.

[0052] Among the exemplified dielectric fillers, since the types are abundant, they can be selected from various shapes and sizes, and the adhesion characteristics and mechanical characteristics of the high-frequency dielectric heating adhesive sheet can be improved according to the application, so the dielectric filler (B) is more preferably zinc oxide. By using zinc oxide as the dielectric filler (B), a colorless high-frequency dielectric heating adhesive sheet can be obtained. Since zinc oxide has a small density among dielectric fillers, when an adherend is joined using a high-frequency dielectric heating adhesive sheet containing zinc oxide as the dielectric filler (B), the total weight of the joined body is less likely to increase compared to the case of using a sheet containing other dielectric fillers. Since zinc oxide does not have too high a hardness among ceramics, it is difficult to damage the manufacturing apparatus of the high-frequency dielectric heating adhesive sheet. Since zinc oxide is an inert oxide, even when blended with a thermoplastic resin, the damage to the thermoplastic resin is small. In addition, the titanium oxide as the dielectric filler (B) is preferably at least one of anatase titanium oxide and rutile titanium oxide, and more preferably anatase titanium oxide from the viewpoint of excellent dielectric properties.

[0053] (Volume content) The volume content of the dielectric filler (B) in the adhesive layer is preferably 10% by volume or more, and more preferably 15% by volume or more. The volume content of the dielectric filler (B) in the adhesive layer is preferably 50% by volume or less, more preferably 40% by volume or less, still 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 adhesive layer is 10% by volume or more, the application time can be further shortened. When the volume content of the dielectric filler (B) in the adhesive layer is 50% by volume or less, it is less likely to embrittle, so the adhesive strength is easily obtained.

[0054] (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 still 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 still more preferably 20 μm or less. When the volume average particle size of the dielectric filler (B) is 1 μm or more, the high-frequency dielectric heating adhesive sheet exhibits high heat generation performance when a high-frequency electric field is applied, and the adhesive layer can firmly adhere to the adherend in a short time. When the volume average particle size of the dielectric filler (B) is 30 μm or less, the high-frequency dielectric heating adhesive sheet exhibits high heat generation performance when a high-frequency electric field is applied, and the adhesive layer can firmly adhere to the adherend in a short time. Also, when the volume average particle size of the dielectric filler (B) is 30 μm or less, a decrease in the strength of the high-frequency dielectric heating adhesive sheet can be prevented.

[0055] The volume average particle size of the dielectric filler (B) is measured by the following method. The particle size distribution of the dielectric filler (B) is measured by the laser diffraction / scattering method, and the volume average particle size is calculated according to JIS Z 8819-2:2001 from the results of the particle size distribution measurement.

[0056] In the high-frequency dielectric heating adhesive sheet according to this embodiment, the average particle size D of the dielectric filler (B) F and the thickness T of the adhesive layer satisfy 1 ≦ T / D FPreferably, it satisfies the relationship of ≦2500. T / D F is preferably 1 or more, preferably 2 or more, preferably 5 or more, more preferably 10 or more, and even more preferably 20 or more. T / D F If it is 1 or more, it is possible to prevent a decrease in the adhesive strength caused by the contact between the dielectric filler (B) and the adherend during adhesion. T / D F is 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. T / D F If it is 2500 or less, it is possible to suppress the load on the sheet manufacturing apparatus when manufacturing the high-frequency dielectric heating adhesive sheet.

[0057] (Additive) The high-frequency dielectric heating adhesive sheet according to this embodiment may or may not contain an additive. When the high-frequency dielectric heating adhesive sheet according to this embodiment is composed of a plurality of layers, at least one of the plurality of layers may or may not contain an additive. When at least one of the plurality of layers contains an additive, the adhesive layer may or may not contain an additive.

[0058] When the high-frequency dielectric heating adhesive sheet according to this embodiment contains an additive, examples of the additive include tackifiers, plasticizers, silane coupling agents, waxes, colorants, antioxidants, ultraviolet absorbers, antibacterial agents, viscosity modifiers, organic fillers, and inorganic fillers. The organic filler and the inorganic filler as the additive are different from the dielectric filler.

[0059] The tackifier and the plasticizer can improve the melting characteristics and the adhesive characteristics of the high-frequency dielectric heating adhesive sheet. Examples of the tackifier 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 the plasticizer include petroleum process oils, natural oils, dialkyl dibasic acids, and low molecular weight liquid polymers. Examples of the petroleum process oil include paraffinic process oils, naphthenic process oils, and aromatic process oils. Examples of the natural oil include castor oil and tall oil. Examples of the dialkyl dibasic acid include dibutyl phthalate, dioctyl phthalate, and dibutyl adipate. Examples of the low molecular weight liquid polymer include liquid polybutene and liquid polyisoprene.

[0060] When the high-frequency dielectric heating adhesive sheet according to this embodiment contains an additive, the content of the additive in the high-frequency dielectric heating adhesive sheet is preferably usually 0.01% by mass or more, more preferably 0.05% by mass or more, and still more preferably 0.1% by mass or more based on the total amount of the high-frequency dielectric heating adhesive sheet. Further, the content of the additive in the high-frequency dielectric heating adhesive sheet is preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 10% by mass or less.

[0061] The high-frequency dielectric heating adhesive sheet according to this embodiment preferably does not contain a solvent. According to the high-frequency dielectric heating adhesive sheet that does not contain a solvent, problems of VOC (Volatile Organic Compounds) caused by the adhesive used for adhesion to the adherend are less likely to occur.

[0062] The adhesive layer of the high-frequency dielectric heating adhesive sheet according to this embodiment preferably does not contain carbon or a carbon compound mainly composed of carbon (for example, carbon black, etc.) and a conductive substance such as metal. 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, and carbon black.

[0063] When the adhesive layer contains a conductive substance, the content of the conductive substance in the adhesive layer is preferably 20% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less, even more preferably 1% by mass or less, and even still more preferably 0.1% by mass or less, each independently based on the total amount of the adhesive layer. The content of the conductive substance in the adhesive layer is particularly preferably 0% by mass. If the content of the conductive substance in the adhesive layer is 20% by mass or less, it becomes easier to prevent problems such as electrical insulation breakdown during dielectric heat treatment and carbonization of the bonded part and the adherend.

[0064] In the adhesive layer of the high-frequency dielectric heating adhesive sheet 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 still more preferably 99% by mass or more.

[0065] As one aspect, the high-frequency dielectric heating adhesive sheet according to this embodiment is composed of only one layer of an adhesive layer having high-frequency dielectric heating adhesiveness. Note that the high-frequency dielectric heating adhesive sheet according to the present invention is not limited to the aspect composed of only one layer of the adhesive layer. Another aspect of the high-frequency dielectric heating adhesive sheet includes an aspect in which layers other than the adhesive layer are laminated. Thus, since the high-frequency dielectric heating adhesive sheet may be composed of only one layer of an adhesive layer having high-frequency dielectric heating adhesiveness, in this specification, the terms "high-frequency dielectric heating adhesive sheet" and "adhesive layer" can be interchanged with each other in some cases. FIG. 2(A) to (C) illustrate schematic views of a plurality of aspects of the high-frequency dielectric heating adhesive sheet according to the present embodiment.

[0066] The high-frequency dielectric heating adhesive sheet 1A shown in FIG. 2(A) is composed of only a single adhesive layer 10. The high-frequency dielectric heating adhesive sheet preferably consists of only a single adhesive layer. By consisting of only a single adhesive layer, the thickness of the high-frequency dielectric heating adhesive sheet can be reduced, and it can be easily formed.

[0067] The high-frequency dielectric heating adhesive sheet 1B shown in FIG. 2(B) has an adhesive layer 10 and a base material 30 that supports the adhesive layer 10. Similar to the high-frequency dielectric heating adhesive sheet 1A, the adhesive layer 10 has a first surface 11. The base material 30 is not particularly limited as long as it is a member that can support the adhesive layer 10. For example, a resin film or a 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 can be mentioned. The base material 30 may contain a dielectric filler (B), and the dielectric filler (B) in the adhesive layer 10 and the dielectric filler in the base material 30 may be the same as or different from each other.

[0068] The high-frequency dielectric heating adhesive sheet 1C shown in Fig. 2(C) has an intermediate layer 40 disposed between an adhesive layer 10 and an 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. In the high-frequency dielectric heating adhesive sheet 1C, the adhesive layer 10 may be referred to as the first adhesive layer, and the adhesive layer 20 may be referred to as the second adhesive layer. In the high-frequency dielectric heating adhesive sheet having a configuration in which an intermediate layer is 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 layer of the high-frequency dielectric heating adhesive sheet according to the present embodiment. In one aspect, both the first adhesive layer and the second adhesive layer are layers having the same composition and characteristics. In one aspect, the second adhesive layer is a high-frequency dielectric heating adhesive layer that is different from the first adhesive layer in at least one of composition and characteristics. In one aspect, the second adhesive layer is a general adhesive layer that is not a high-frequency dielectric heating adhesive layer. As the second adhesive layer that is not a high-frequency dielectric heating adhesive layer, for example, a drying and solidifying type adhesive layer in which water or a solvent evaporates and dries and solidifies, or an adhesive layer formed from an adhesive (pressure-sensitive adhesive) is used.

[0069] (Form and characteristics of high-frequency dielectric heating adhesive sheet) In one aspect, the high-frequency dielectric heating adhesive sheet according to the present embodiment consists of only one layer of the adhesive layer, and in another aspect, it may consist of a plurality of layers. When the high-frequency dielectric heating adhesive sheet consists of only one layer of the adhesive layer, since the adhesive layer itself corresponds to the high-frequency dielectric heating adhesive sheet, the form and characteristics of the high-frequency dielectric heating adhesive sheet correspond to the form and characteristics of the adhesive layer.

[0070] (Thickness of high-frequency dielectric heating adhesive sheet) The thickness of the high-frequency dielectric heating adhesive sheet according to the present embodiment is preferably 5 μm or more, more preferably 10 μm or more, still 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, when adhering to the adherend, the high-frequency dielectric heating adhesive sheet easily follows the unevenness of the adherend, and the adhesive strength is easily developed. When the high-frequency dielectric heating adhesive sheet has a multi-layer structure composed of a plurality of layers, the thickness of the adhesive layer is preferably 5 μm or more, more preferably 10 μm or more, still 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-layer sheet, if the thickness of the adhesive layer is 5 μm or more, when adhering to the adherend, the adhesive layer can easily follow the unevenness of the adherend, and the adhesive strength can be easily developed. The upper limit of the thickness of the high-frequency dielectric heating adhesive sheet is not particularly limited. 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 and the adherend also increases. Therefore, the high-frequency dielectric heating adhesive sheet preferably has a thickness within a range that causes no problems in actual use. Considering the practicality and moldability 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 still more preferably 600 μm or less.

[0071] (Dielectric properties (tanδ / ε’) of the high-frequency dielectric heating adhesive sheet) The dielectric tangent (tanδ) and the relative permittivity (ε’) as the dielectric properties of the high-frequency dielectric heating adhesive sheet can be measured in accordance with JIS C 2138:2007, but can be measured simply and accurately according to the impedance material method. The dielectric properties (tanδ / ε’) of the high-frequency dielectric heating adhesive sheet are preferably 0.005 or more, more preferably 0.008 or more, and still more preferably 0.01 or more. Also, the dielectric properties (tanδ / ε’) of the high-frequency dielectric heating adhesive sheet are preferably 0.08 or less, more preferably 0.05 or less. The dielectric properties (tanδ / ε’) are the values obtained by dividing the dielectric tangent (tanδ) measured using an impedance material device or the like by the relative permittivity (ε’) measured using an impedance material device or the like. If the dielectric property of the high-frequency dielectric heating adhesive sheet is 0.005 or more, when the dielectric heating treatment is performed, it is possible to prevent the problem that the adhesive bodies cannot be firmly adhered to each other without generating predetermined heat. If the dielectric property of the high-frequency dielectric heating adhesive sheet is 0.08 or less, damage to the adherend is less likely to occur. The details of the method for measuring the dielectric property of the high-frequency dielectric heating adhesive sheet are as follows. For the high-frequency dielectric heating adhesive sheet cut to a predetermined size, using an impedance material analyzer E4991 (manufactured by Agilent), under the conditions of a frequency of 40.68 MHz at 23°C, the dielectric constant (ε') and the dielectric loss tangent (tanδ) are measured respectively, and the value of the dielectric property (tanδ / ε') is calculated.

[0072] (Method for manufacturing a high-frequency dielectric heating adhesive sheet) The single-layer high-frequency dielectric heating adhesive sheet can be manufactured by preliminarily mixing the above-mentioned components and kneading them using a known kneading device such as an extruder and a hot roll, and then by a known forming method such as extrusion molding, calender molding, injection molding, and casting molding. When the high-frequency dielectric heating adhesive sheet according to this embodiment has a multilayer structure, for example, it can be manufactured by preliminarily mixing the above-mentioned components and using a co-extrusion method using a multilayer extruder. Also, a single-layer sheet of each layer (for example, the first adhesive layer, the intermediate layer, and the second adhesive layer) constituting the high-frequency dielectric heating adhesive sheet according to this embodiment can be separately produced, and a multilayer sheet can also be manufactured by laminating a plurality of single-layer sheets through a lamination process. When laminating a plurality of single-layer sheets, for example, a thermal laminator is used. In addition, the high-frequency dielectric heating adhesive sheet according to this embodiment can also be manufactured by thermal extrusion coating or hot melt coating in which the molten adhesive layer is coated on the base material, or by wet coating in which a coating solution in which the adhesive layer composition is dispersed or dissolved in a solvent is coated on the base material.

[0073] [Second Embodiment] Next, a second embodiment of the present invention will be described. In addition, in the present embodiment, the configuration is the same as that of the first embodiment except that the first step and the second step are defined based on the applied energy per unit area instead of the applied output per unit area. Therefore, the first step and the second step will be described, and the other descriptions will be omitted. The adhesion method according to the present embodiment includes a first step of applying a high-frequency electric field with an applied energy J1 per unit area to the high-frequency dielectric heating adhesive sheet, and a second step of applying a high-frequency electric field with an applied energy J2 per unit area to the high-frequency dielectric heating adhesive sheet after the first step. The applied energy J1 per unit area in the first step and the applied energy J2 per unit area in the second step satisfy the condition represented by the following mathematical formula (Formula 3). In the present embodiment, similar to the first embodiment, a mode of adhering a first adherend and a second adherend using a high-frequency dielectric heating adhesive sheet composed of a single adhesive layer will be described as an example. J1 > 0.75 × J2…(Formula 3) Here, J1 and J2 can be calculated by the following mathematical formulas (Formula 4-1) and (Formula 4-2), respectively. J1 (W / mm 2 ·sec) = T1 × V1…(Formula 4-1) J2 (W / mm 2 ·sec) = T2 × V2…(Formula 4-2)

[0074] When the condition represented by the above mathematical formula (Formula 3) is not satisfied, it is impossible to improve the adhesion strength while shortening the application time of the high-frequency electric field. Note that both the applied energy J1 per unit area in the first step and the applied energy J2 per unit area in the second step are greater than 0 W / mm 2 ·sec. Also, from the same viewpoint, the lower limit of the applied energy J1 per unit area in the first step is preferably 0.85 times or more the value of the applied energy J2 per unit area in the second step, and more preferably 1 time or more the value of the applied energy J2 per unit area in the second step. From the perspective of shortening the application time, the upper limit of the energy J1 applied per unit area in the first step is preferably 10 times or less, more preferably 5 times or less, the value of the energy J2 applied per unit area in the second step.

[0075] In this embodiment, it is preferable that the energy J1 applied per unit area in the first step and the energy J2 applied per unit area in the second step satisfy the condition represented by the following mathematical formula (Formula 3-1). 0.9 > J1 / (J1 + J2) > 0.4…(Formula 3-1) When the condition represented by the above mathematical formula (Formula 3-1) is satisfied, it is easy to improve the adhesive strength. From the same perspective, the upper limit of the value of J1 / (J1 + J2) is preferably 0.85 or less, more preferably 0.8 or less, and particularly preferably 0.75 or less. The lower limit of the value of J1 / (J1 + J2) is preferably 0.42 or more, more preferably 0.44 or more, and particularly preferably 0.5 or more.

[0076] The energy J1 applied per unit area in the first step is preferably 2 W / mm 2 · seconds or more, more preferably 3 W / mm 2 · seconds or more, and particularly preferably 3.5 W / mm 2 · seconds or more. The energy J1 applied per unit area in the first step is preferably 9 W / mm 2 · seconds or less, more preferably 7 W / mm 2 · seconds or less, and particularly preferably 5 W / mm 2 · seconds or less. If the energy J1 applied per unit area in the first step is 2 W / mm 2 · seconds or more, the problem that the resin is unlikely to be in a molten state can be prevented, so that a good adhesive force can be easily obtained. If the energy J1 applied per unit area in the first step is 9 W / mm 2·If it is less than one second, the resin will foam, preventing the problem of reduced adhesive strength, and thus good adhesive force can be easily obtained.

[0077] The total applied energy (J1 + J2), which is the sum of the applied energy J1 per unit area in the first step and the applied energy J2 per unit area in the second step, is 3 W / mm 2 ·It is preferably at least 3 W / mm·second, more preferably 2 ·at least 4.5 W / mm·second, and particularly preferably 2 ·at least 6 W / mm·second. The total applied energy (J1 + J2) is preferably at most 20 W / mm 2 ·second, more preferably 2 ·at most 15 W / mm·second, and particularly preferably 2 ·at most 10 W / mm·second. If the value of the total applied energy (J1 + J2) is within the above range, it is easy to improve the adhesive strength.

[0078] [Modifications of the Embodiment] The present invention is not limited to the above embodiment. The present invention can include modifications, improvements, etc. within the scope that can achieve the object of the present invention.

[0079] In the above embodiment, the second step is performed following the first step, but it is not limited thereto. For example, if it seems not to impair the effects of the present invention, other steps may be performed between the first step and the second step. Here, examples of other steps include a step of leaving it for a while after performing the first-stage high-frequency dielectric heating as the first step.

[0080] The high-frequency dielectric heat treatment is not limited to the dielectric heat bonding apparatus in which the electrodes described in the above embodiment are arranged opposite to each other, and a grid electrode type high-frequency dielectric heating apparatus may be used. The grid electrode type high-frequency dielectric heating apparatus has a grid electrode in which electrodes of a first polarity and electrodes of a second polarity opposite to the electrodes of the first polarity are alternately arranged on the same plane at regular intervals. For example, when manufacturing a joined body by overlapping and adhering the end of a first adherend and the end of a second adherend, a grid electrode type high-frequency dielectric heating device is arranged on the first adherend side or the second adherend side to apply a high-frequency electric field.

[0081] When adhering a first adherend and a second adherend using a grid electrode type high-frequency dielectric heating device, a first grid electrode is arranged on the first adherend side, and a second grid electrode is arranged on the second adherend side, and the first adherend, the high-frequency dielectric heating adhesive sheet, and the second adherend are sandwiched between the first grid electrode and the second grid electrode, and a high-frequency electric field may be applied simultaneously.

[0082] When adhering a first adherend and a second adherend using a grid electrode type high-frequency dielectric heating device, a grid electrode is arranged on one surface side of the first adherend and the second adherend, a high-frequency electric field is applied, and then a grid electrode is arranged on the other surface side of the first adherend and the second adherend, and a high-frequency electric field may be applied.

[0083] It is also preferable to use a grid electrode type high-frequency dielectric heating device for applying the high-frequency electric field. By using a grid electrode type high-frequency dielectric heating device, it is not affected by the thickness of the first adherend and the second adherend, and dielectric heating is performed from the adherend side where the distance to the surface layer side of the first adherend and the second adherend, for example, up to the high-frequency dielectric heating adhesive sheet is short, so that the adherends can be adhered to each other. In addition, by using a grid electrode type high-frequency dielectric heating device, energy saving in the manufacture of the joined body can be realized.

[0084] In the figure, for the sake of simplicity, an embodiment using a dielectric heating adhesive device with electrodes arranged opposite to each other is illustrated.

Example

[0085] Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to these examples at all.

[0086] [Production of High-Frequency Dielectric Heating Adhesive Sheet] As a thermoplastic resin component, 80.0% by volume of maleic anhydride copolymer polypropylene (manufactured by Mitsubishi Chemical Corporation, Modic P565, hereinafter referred to as Component A) and, as Component B, 20.0% by volume of zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd., LPZINC11, average particle diameter: 11 μm, hereinafter referred to as Component B) were weighed into a container respectively. The weighed Component A and Component B were premixed in the container. After premixing each component, they were supplied to the hopper of a 30 mm Φ twin-screw extruder, the cylinder set temperature was set at 180 °C or higher and 200 °C or lower, the die temperature was set at 200 °C, and melt kneading was performed to obtain granular pellets. Next, the obtained granular pellets were put into the hopper of a single-screw extruder equipped with a T-die. Under the conditions of a cylinder temperature of 200 °C and a die temperature of 200 °C, a film-like melt-kneaded product was extruded from the T-die and cooled by a cooling roll to produce a high-frequency dielectric heating adhesive sheet with a thickness of 400 μm. Regarding the obtained sheet, a dielectric material test fixture 16453A (manufactured by Agilent) was attached to an impedance material analyzer E4991ARF (manufactured by Agilent), and the relative permittivity (ε’r) and dielectric loss tangent (tanδ) were measured at a frequency of 40.68 MHz at 23 °C by the parallel plate method. Based on the measurement results, the value of the dielectric property (tanδ / ε’r) was calculated. The dielectric property (tanδ / ε’r) of the obtained high-frequency dielectric heating adhesive sheet was 0.014.

[0087] [Example 1] The produced high-frequency dielectric heating adhesive sheet was cut into a size of 25 mm × 12.5 mm. After sandwiching the cut high-frequency dielectric heating adhesive sheet between a pair of epoxy glass plates (25 mm × 100 mm × 1.5 mm) as adherends, it was fixed between the electrodes of a high-frequency dielectric heating device (manufactured by Yamamoto Vinita Co., Ltd., TRP-400T-RC), and the frequency was set at 40.68 MHz and the estimated pressing pressure was set at 192.8 N. And as the first step, the applied area was 312.5 mm 2 , the applied output was 100 W (the applied output V1 per unit area was 0.32 W / mm 2) Set the Inca time to 15 seconds and perform the first-stage high-frequency dielectric heating. Next, as the second step, set the application area to 312.5 mm 2 , set the application output to 50 W (the application output V2 per unit area is 0.16 W / mm 2 ), set the application time to 10 seconds, perform the second-stage high-frequency dielectric heating, and fabricate a bonded body. The application output, application time T1, and application output V1 per unit area in the first step, as well as the application output, application time T2, and application output V2 per unit area in the second step, are shown in Table 1. Furthermore, the application energy J1 per unit area in the first step, the application energy J2 per unit area in the second step, the total application time (T1 + T2), the total application energy (J1 + J2), and the value of J1 / (J1 + J2) are shown in Table 2. The bonding strength of the obtained bonded body was measured according to JIS K 6850. The obtained results are shown in Table 1.

[0088] [Examples 2 - 8] A bonded body was fabricated in the same manner as in Example 1, except that the conditions of the first step and the second step were changed as shown in Table 1 below. Also, the bonding strength of the obtained bonded body was measured in the same manner as in Example 1. The obtained results are shown in Table 1. In addition, the application energy J1 per unit area in the first step, the application energy J2 per unit area in the second step, the total application time (T1 + T2), the total application energy (J1 + J2), and the value of J1 / (J1 + J2) are shown in Table 2.

[0089] [Comparative Example 1] In the same manner as in Example 1, after sandwiching the cut high-frequency dielectric heating adhesive sheet between epoxy glass plates as a pair of adherends, it was set in a high-frequency dielectric heating device. Then, without dividing the high-frequency dielectric heating into two steps, set the application area to 312 mm 2 , set the application output to 100 W (the application output V1 per unit area is 0.32 W / mm 2) Set the Inca time to 30 seconds, perform high-frequency dielectric heating, and fabricate a bonded body. The applied output, applied time, and applied output V1 per unit area in high-frequency dielectric heating are shown in Table 1. Also, the applied energy J1 per unit area, total applied time (T1 + T2), total applied energy (J1 + J2), and the value of J1 / (J1 + J2) in high-frequency dielectric heating are shown in Table 2.

[0090] [Comparative Examples 2 to 4] A bonded body was fabricated in the same manner as in Comparative Example 1, except that the conditions of high-frequency dielectric heating were changed as shown in Table 1 below. Also, the bonding strength of the obtained bonded body was measured in the same manner as in Example 1. The obtained results are shown in Table 1. Also, the applied energy J1 per unit area, total applied time (T1 + T2), total applied energy (J1 + J2), and the value of J1 / (J1 + J2) in high-frequency dielectric heating are shown in Table 2.

[0091] [Comparative Example 5] A bonded body was fabricated in the same manner as in Example 1, except that the conditions of the first step and the second step were changed as shown in Table 1 below. Also, the bonding strength of the obtained bonded body was measured in the same manner as in Example 1. The obtained results are shown in Table 1. Also, the applied energy J1 per unit area in the first step, the applied energy J2 per unit area in the second step, total applied time (T1 + T2), total applied energy (J1 + J2), and the value of J1 / (J1 + J2) are shown in Table 2.

[0092]

Table 1

[0093]

Table 2

[0094] According to the bonding methods of Examples 1 to 8, it was possible to shorten the application time of the high-frequency electric field and improve the bonding strength even with a short application time.

Explanation of Reference Signs

[0095] 10…Adhesive layer (first adhesive layer), 11…First surface, 110…Adherend, 120…Adherend, 1A…High-frequency dielectric heating adhesive sheet, 1B…High-frequency dielectric heating adhesive sheet, 1C…High-frequency dielectric heating adhesive sheet, 20…Adhesive layer (second adhesive layer), 21…Second surface, 30…Base material, 40…Intermediate layer, 50…Dielectric heating adhesive device, 51…First high-frequency electric field applying electrode, 52…Second high-frequency electric field applying electrode, 53…High-frequency power supply.

Claims

1. A method for adhering an adherend using a high-frequency dielectric heating adhesive sheet, comprising: the high-frequency dielectric heating adhesive sheet contains a thermoplastic resin (A); a first step of applying a high-frequency electric field with an applied output V1 per unit area to the high-frequency dielectric heating adhesive sheet; a second step of applying a high-frequency electric field with an applied output V2 per unit area to the high-frequency dielectric heating adhesive sheet after the first step; and the applied output V1 per unit area in the first step is 0.22 W / mm2 or more and 0.5 W / mm2 or less; the applied output V2 per unit area in the second step is 0.11 W / mm2 or more and 0.18 W / mm2 or less; the applied output V1 per unit area in the first step and the applied output V2 per unit area in the second step satisfy the condition represented by the following formula (Formula 1): Adhesion method. 0.7 × V1 ≥ V2 ≥ 0.4 × V1... (Formula 1)

2. The application time T1 in the first step is 1 second or more and less than 25 seconds, The adhesion method according to Claim 1.

3. The application time T2 in the second step is 5 seconds or more, The adhesion method according to Claim 1 or Claim 2.

4. The application time T1 in the first step and the application time T2 in the second step satisfy the condition represented by the following formula (Formula 2): The adhesion method according to any one of Claims 1 to 3. (T1 + T2) < 60 seconds... (Formula 2)

5. A method for adhering an adherend using a high-frequency dielectric heating adhesive sheet, comprising: the high-frequency dielectric heating adhesive sheet contains a thermoplastic resin (A); a first step of applying a high-frequency electric field with an applied energy J1 per unit area to the high-frequency dielectric heating adhesive sheet; a second step of applying a high-frequency electric field with an applied energy J2 per unit area to the high-frequency dielectric heating adhesive sheet after the first step; and the applied energy J1 per unit area in the first step is 3.5 W / mm2·s or more and 5 W / mm2·s or less; the total applied energy (J1 + J2), which is the sum of the applied energy J1 per unit area in the first step and the applied energy J2 per unit area in the second step, is 6 W / mm2·s or more and 10 W / mm2·s or less; the applied energy J1 per unit area in the first step and the applied energy J2 per unit area in the second step satisfy the condition represented by the following formula (Formula 3): Adhesion method. J1 ≥ J2... (Formula 3)

6. The applied energy J1 per unit area in the first step and the applied energy J2 per unit area in the second step satisfy the condition represented by the following mathematical formula (Equation 3-1): The adhesion method according to claim 5. 0.9 > J1 / (J1 + J2) > 0.4…(Equation 3-1)

7. The thermoplastic resin (A) is a polyolefin resin. The adhesion method according to any one of claims 1 to 6.

8. The high-frequency dielectric heating adhesive sheet further includes a dielectric filler (B) that generates heat when a high-frequency electric field is applied. The adhesion method according to any one of claims 1 to 7.

9. The dielectric filler (B) includes at least any one selected from the group consisting of zinc oxide, silicon carbide, barium titanate, and titanium oxide. The adhesion method according to claim 8.

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