WO2023013651A1

WO2023013651A1 - Bonding method

Info

Publication number: WO2023013651A1
Application number: PCT/JP2022/029692
Authority: WO
Inventors: 直紀田矢; 泰之天野
Original assignee: リンテック株式会社
Priority date: 2021-08-06
Filing date: 2022-08-02
Publication date: 2023-02-09
Also published as: CN117677483A; TW202328368A; JPWO2023013651A1

Abstract

A bonding method for bonding an adherend (120) with an adhesive (11) for high-frequency dielectric heating, the bonding method comprising a placement step in which the electrodes of a dielectric heater (50), the adherend (120), and a spacer (210) are placed and a high-frequency electric-field application step in which a high-frequency electric field is applied to the adhesive (11) for high-frequency dielectric heating to bond the adherend (120). The adherend (120) has a first surface, which includes recessed and protrudent portions, and the adhesive (11) for high-frequency dielectric heating comprises a thermoplastic resin. In the placement step, after the adherend (120) and the spacer (210) have been placed, there are spaces (31) formed between the first surface of the adherend (120) and the surface of the spacer (210) which faces the first surface, and the spaces (31) are filled by a deformation of the spacer (210).

Description

Joining method

The present invention relates to a joining method.

As a method of joining adherends using an adhesive, a method of joining adherends by high-frequency dielectric heating treatment or the like has been proposed. For example, in some cases, an adherend having an undulating surface on at least one surface of the adherend is bonded by high-frequency dielectric heating using an adhesive. In this case, the undulating surface side of the adherend having the undulating surface may be arranged on the electrode surface side of the high-frequency dielectric heating device, and the bonding may be performed by arranging an adhesive on the surface opposite to the electrode surface.

For example, in Patent Document 1, a water-based adhesive is applied to the adherend surface of the adherend portion of one adherend, and the adherend surface of one adherend and the adherend surface of the other adherend are disclosed. and applying high-frequency dielectric heating while pressing the superimposed adherend surfaces to join two adherends, one adherend and the other adherend.

JP-A-2004-222990

When bonding is performed by arranging the undulating surface side of the adherend having the undulating surface on the electrode surface side of the high-frequency dielectric heating device and placing an adhesive on the surface opposite to the electrode surface side, the high-frequency dielectric heating device A space is generated between the electrode surface and the undulating surface of the adherend. Then, when a high-frequency electric field is applied to the adhesive, the high-frequency energy is less likely to be transmitted to the adhesive placed at the position corresponding to this space, and the undulating surface of the adherend and the high-frequency dielectric The high-frequency energy is selectively transmitted to the adhesive placed at the position corresponding to the portion in contact with the electrode of the heating device. As a result, the application of the high-frequency electric field to the adhesive becomes non-uniform, making it difficult to firmly bond the adherend and the adhesive in a short period of time.

In the joining technique disclosed in Patent Document 1, in order to fill the space generated when the undulating surface of the adherend having the undulating surface is arranged on the electrode surface side of the high-frequency dielectric heating device, the undulations of the adherend are prepared in advance. A plurality of adherends are joined using a compression plate molded into a shape corresponding to the surface. However, in the joining technique disclosed in Patent Document 1, it is time-consuming to prepare a pressure-bonding plate molded for each shape of the undulating surface. Thus, there is room for further improvement in the technique of arranging an adherend having an undulating surface on the electrode surface side of a high-frequency dielectric heating device and joining them by high-frequency dielectric heating treatment.

An object of the present invention is to provide a technique of placing an adherend having an undulating surface on the electrode surface side of a high-frequency dielectric heating device and bonding it by high-frequency dielectric heating, in which a crimping die (crimping) is formed in advance according to the shape of the undulating surface (crimping To provide a bonding method capable of firmly bonding the adherends in a short time without preparing a plate.

[1]
A bonding method for bonding adherends using a high-frequency dielectric heating adhesive, comprising an arrangement step of arranging an electrode of a dielectric heating device, the adherend and a spacer, and a high-frequency electric field in the high-frequency dielectric heating adhesive. and a high-frequency electric field application step of bonding the adherend by applying a high-frequency electric field, wherein the adherend has a first surface having an undulating surface, and the high-frequency dielectric heating adhesive is a thermoplastic resin and in the arranging step, when the adherend and the spacer are arranged, a space is formed between the first surface of the adherend and the surface of the spacer facing the first surface The bonding method, wherein the space is filled by deformation of the spacer.

[2]
The bonding method according to [1], wherein the space is filled by deformation of the spacer when the electrode presses the adherend and the spacer.

[3]
wherein in the high-frequency electric field application step, the adherend is joined by applying a high-frequency electric field while pressing the adherend and the high-frequency dielectric heating adhesive with the electrode to join the adherend; Joining method as described.

[4]
The bonding method according to any one of [1] to [3], wherein the high-frequency dielectric heating adhesive and the adherend are respectively arranged in the arrangement step.

[5]
The bonding method according to any one of [1] to [4], wherein in the placing step, the first surface of the adherend is placed facing the side opposite to the high-frequency dielectric heating adhesive. .

[6]
The method according to any one of [1] to [5], wherein in the arranging step, two or more adherends are arranged, and at least one adherend is the adherend having the first surface. Joining method as described.

[7]
The bonding method according to any one of [1] to [6], wherein the undulating surface of the adherend has a maximum height difference of 1 mm or more.

[8]
The undulations of the first surface of the adherend include concave portions and convex portions, and when the first surface of the adherend is viewed in plan, the area ratio of the concave portions to the first surface is 20. % or more and less than 100%, the joining method according to any one of [1] to [7].

[9]
The thickness of the spacer according to any one of [1] to [8], wherein the thickness of the spacer is 50% or more with respect to the maximum height difference of the undulations of the undulation surface provided on the first surface of the adherend. Joining method as described.

[10]
The bonding method according to any one of [1] to [9], wherein the spacer has a dielectric property (tan δ/ε'r) of 0.003 or less.
(tan δ is the dielectric loss tangent at 23° C. and a frequency of 40.68 MHz, and ε′r is the relative permittivity at 23° C. and a frequency of 40.68 MHz.)

[11]
The joining method according to any one of [1] to [10], wherein the spacer is an insulator.

[12]
The bonding method according to any one of [1] to [11], wherein bonding is performed so that the space followability FP of the spacer represented by the following formula 1 is 50% or more.
FP=(S2/S1)×100 (Equation 1)
S1: an area corresponding to the shape of the opening of the space of the adherend before the spacer follows the adherend when the space of the adherend is viewed from above S2: the space When a coloring agent is attached to the inner surface of the portion and the interior of the space is filled by deformation of the spacer, a portion where the coloring agent is attached to the surface of the spacer in the portion that fills the space is viewed from above. area when

[13]
The bonding method according to any one of [1] to [12], wherein the high-frequency dielectric heating adhesive further contains a dielectric material that generates heat when a high-frequency electric field is applied.

[14]
[13], wherein the dielectric material is a dielectric filler (B), and the dielectric filler (B) is at least one selected from the group consisting of zinc oxide, silicon carbide, titanium oxide and barium titanate; Joining method as described.

[15]
The bonding method according to any one of [1] to [14], wherein the dielectric property (tan δ/ε'r) of the high-frequency dielectric heating adhesive is 0.005 or more.
(tan δ is the dielectric loss tangent at 23° C. and a frequency of 40.68 MHz, and ε′r is the relative permittivity at 23° C. and a frequency of 40.68 MHz.)

According to one aspect of the present invention, in a technique of arranging an adherend having an undulating surface on the electrode surface side of a high-frequency dielectric heating device and bonding by high-frequency dielectric heating treatment, the crimping is formed in advance according to the shape of the undulating surface. It is possible to provide a joining method capable of firmly joining the adherends in a short time without preparing a mold.

It is the schematic explaining an example of the joining method which concerns on this embodiment. It is the schematic explaining an example of the joining method which concerns on this embodiment. It is the schematic explaining an example of the joining method which concerns on this embodiment. It is a sectional view showing an example of an adherend used for a joining method concerning this embodiment. It is a sectional view showing an example of an adherend used for a joining method concerning this embodiment. FIG. 4 is a conceptual diagram illustrating a method for measuring spatial followability; FIG. 4 is a conceptual diagram illustrating a method for measuring spatial followability; FIG. 4 is a conceptual diagram illustrating a method for measuring spatial followability; FIG. 4 is a conceptual diagram illustrating a method for measuring spatial followability; FIG. 4 is a conceptual diagram illustrating a method for measuring spatial followability; FIG. 4 is a conceptual diagram illustrating a method for measuring spatial followability; 1 is a schematic diagram of a high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment; FIG. 1 is a schematic diagram of a high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment; FIG. 1 is a schematic diagram of a high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment; FIG. 1 is a schematic diagram of a first adherend WK1 used in Examples. FIG. 1 is a schematic diagram of a first adherend WK1 used in Examples. FIG. It is the schematic showing the side surface of the test piece for bondability evaluation.

[Joining method]
The bonding method according to the present embodiment is a bonding method for bonding adherends using a high-frequency dielectric heating adhesive, and includes an arrangement step of arranging an electrode of a dielectric heating device, an adherend, and a spacer, and a high-frequency dielectric a high-frequency electric field application step of applying a high-frequency electric field to the heating adhesive to join the adherends. The adherend has a first surface having an undulating surface, and the high-frequency dielectric heating adhesive includes a thermoplastic resin. In the arranging step, when the adherend and the spacer are arranged, a space is formed between the first surface of the adherend and the surface of the spacer facing the first surface, and the space is formed by the spacer. Filled by deformation. In this specification, the dielectric heating device may be referred to as a high-frequency dielectric heating device.

The adherend used in the bonding method according to this embodiment has a first surface having an undulating surface and a second surface opposite to the first surface. The second surface need not have an undulating surface. The undulating surface of the adherend has a raised portion and a depressed portion, and the depressed portion may be present at one location or at a plurality of locations. Similarly, the raised portion may be present at one location or may be present at a plurality of locations. When there are a plurality of depressed portions, the depth of the depressed portions may be substantially uniform or may be uneven. When there are a plurality of protruded parts, the height of the protruded parts may or may not be uniform. When there are a plurality of raised portions and depressed portions, the raised portions and depressed portions may be scattered or densely packed. Further, when the undulating surface is viewed in cross section, the recessed portion may have a single arcuate concave shape, or may exist at a plurality of locations. The protruded portion may have a single arcuate convex shape, or may be present at a plurality of locations. Hereinafter, the adherend having the first surface having the undulating surface may be referred to as an adherend (X) for convenience.

In one aspect of the bonding method according to the present embodiment, in the placement step, first, the first surface side of the adherend (X) is directed toward the electrode side of the dielectric heating device, and the electrode and the adherend (X) are Place a spacer in between. By arranging the spacer, a space is formed between the first surface of the adherend (X) and the surface of the spacer facing the first surface. The shape of the space is a shape corresponding to the shape of the space formed between the undulating surface of the adherend (X) and the spacer. By deforming the spacer, at least part of the space is filled according to the shape of the space. At this time, the high-frequency dielectric heating adhesive is placed on the second surface side of the adherend (X). Next, in the high-frequency electric field application step, a high-frequency electric field is applied to the high-frequency dielectric heating adhesive in a state where the space is filled by deformation of the spacer, and the high-frequency dielectric heating adhesive and the adherend (X ).

In the joining method according to the present embodiment, the deformation of the spacer fills the space, thus saving the trouble of preparing a crimping die that has been molded according to the shape of the undulating surface in advance. In the bonding method according to the present embodiment, since the dielectric heating is performed in a state where the space is filled by the deformation of the spacer, the energy of the high-frequency dielectric heating is almost uniform with respect to the high-frequency dielectric heating adhesive. It becomes easier to convey. As a result, the adherend (X) and the high-frequency dielectric heating adhesive can be firmly bonded in a short time.

In the joining method according to the present embodiment, the number of adherends is not particularly limited, and the number of spacers is also not limited, as long as at least one adherend having a first surface having an undulating surface can be joined. Even in this case, in the bonding method according to the present embodiment, the adherend (X) and the high-frequency dielectric heating adhesive can be firmly bonded in a short time. The adherends can be strongly bonded together in a short period of time.

A bonding method according to one aspect of the present embodiment includes an arrangement step (step P1) of arranging an electrode of a dielectric heating device, an adherend, and a spacer, and applying a high-frequency electric field to an adhesive for high-frequency dielectric heating, includes a high-frequency electric field application step (step P2) for bonding.

Each step of the joining method according to this embodiment will be described below.

・Process P1
Step P1 is a step of arranging the electrode of the dielectric heating device, the adherend (X), and the spacer. In step P1, the first surface of the adherend (X) and the spacer are arranged to face each other, and between the first surface of the adherend (X) and the surface of the spacer facing the first surface , a space is formed. The space is filled by deformation of the spacer.

In step P1, the order of arranging the electrodes, adherends (X), and spacers is not particularly limited. For example, the adherend (X) and spacers may be placed after placing the electrodes, or the electrodes may be placed after placing the adherend (X) and spacers. The order in which the adherend (X) and the spacer are placed is not particularly limited, and either the adherend (X) or the spacer may be placed first, or both may be placed at the same time.

In step P1, the space formed between the first surface of the adherend (X) and the surface of the spacer facing the first surface is filled by deformation of the spacer. The order in which the space is filled by deformation of the spacer is not particularly limited, and the space may be filled after the adherend (X) and the spacer are placed. For example, after arranging the spacer and the adherend (X) on the electrode of the dielectric heating device, the space of the adherend (X) may be filled with the spacer. Specifically, the space may be filled by deformation of the spacer when pressure is applied to the adherend (X) and the spacer by electrodes of a dielectric heating device.
Further, in step P1, the adherend (X) and the spacer may be placed after filling the space by deformation of the spacer. For example, before arranging the spacer and the adherend (X) on the electrode of the dielectric heating device, the space of the adherend (X) is previously filled with the spacer, and then the spacer and the adherend ( X) may be placed on the electrodes of the dielectric heating device. Specifically, after filling the space by deforming clay, putty, or the like as a spacer, the adherend (X) and the spacer may be placed on the electrode of the dielectric heating device.
In addition, if a space is formed between the adherend (X) and the spacer when the spacer is arranged, and the space can be filled by deformation of the spacer, the spacer is the undulating surface of the adherend (X). may not be arranged on the entire surface of the For example, a spacer placed between the undulating surface of the adherend (X) and the electrode is placed between the recessed portion of the undulating surface of the adherend (X) and the electrode, and the adherend ( It may not be located between the raised portion of the undulating surface of X) and the electrode.

In step P1, the number of adherends is not particularly limited, and two or more adherends may be arranged. When arranging two or more adherends, at least one adherend is the adherend (X). For example, when joining two adherends (X) with a high-frequency dielectric heating adhesive, the high-frequency dielectric heating adhesive is placed between the second surfaces of both adherends (X), and the electrode and A spacer may be placed between the first surfaces of both adherends (X) for bonding. Further, for example, when the adherend (X) and an adherend having neither the first surface nor the second surface having undulating surfaces are joined by a high-frequency dielectric heating adhesive, the undulations of the two adherends A high-frequency dielectric heating adhesive may be placed between the surfaces having no surfaces, and a spacer may be placed between the electrode and the first surface of the adherend (X) for bonding. Furthermore, when joining three or more adherends including at least one adherend (X), the high-frequency dielectric heating adhesive is placed between the non-undulating surfaces of each adherend. Alternatively, the adherends and the high-frequency dielectric heating adhesive may be alternately arranged and bonded.

In step P1, the high-frequency dielectric heating adhesive and the adherend (X) may be placed respectively. When arranging two or more adherends, the high-frequency dielectric heating adhesive is arranged as a high-frequency dielectric heating adhesive integrated with the second surface side of the adherend (X) having no undulating surface. You may The high-frequency dielectric heating adhesive may be arranged as a high-frequency dielectric heating adhesive integrated with an adherend that does not have undulating surfaces on both the first and second surfaces. In either case, the first surface of the adherend (X) is placed facing away from the high-frequency dielectric heating adhesive. That is, the high-frequency dielectric heating adhesive is placed on the surface opposite to the first surface of the adherend (X).

When two or more adherends including the adherend (X) are to be joined, the step P1 is to apply the high-frequency dielectric heating adhesive to the adherend having an undulating surface so that the adherends can be joined together. It is preferable to sandwich between non-contact surfaces. The high-frequency dielectric heating adhesive may be sandwiched between a part of the adherends, at a plurality of locations between the adherends, or over the entire surface between the adherends. From the viewpoint of improving the adhesive strength between the adherends, it is preferable to sandwich the high-frequency dielectric heating adhesive over the entire joint surface between the adherends.
Further, as one aspect of sandwiching the high-frequency dielectric heating adhesive in part between the adherends, the high-frequency dielectric heating adhesive is arranged in a frame shape along the outer periphery of the bonding surface between the adherends, A mode in which it is sandwiched between adherends is exemplified. By arranging the high-frequency dielectric heating adhesive in a frame shape in this way, the bonding strength between the adherends can be obtained, and the structure can be compared with the case where the high-frequency dielectric heating adhesive is arranged over the entire bonding surface. can be made lighter.
In addition, according to one mode in which the high-frequency dielectric heating adhesive is sandwiched between parts of the adherends, the amount of the high-frequency dielectric heating adhesive to be used can be reduced and the size can be reduced. The high-frequency dielectric heating treatment time can be shortened compared to the case where the high-frequency dielectric heating adhesive is used.

・Process P2
Step P2 is a step of applying a high-frequency electric field to the high-frequency dielectric heating adhesive to join the adherend (X) after arranging each member in the step P1. When bonding two or more adherends including the adherend (X) in step P2, in step P1, a high-frequency electric field is applied to the high-frequency dielectric heating adhesive placed between the adherends. It is a step of joining two or more adherends. In one embodiment, the frequency of the applied high-frequency electric field is 3 MHz or more and 300 MHz or less. For example, by using a dielectric heating device, a high frequency electric field can be applied to the high frequency dielectric heating adhesive. In step P2, the adherend (X) may be joined by applying a high-frequency electric field while pressing the adherend (X) and the high-frequency dielectric heating adhesive with an electrode.

(High-frequency dielectric heating conditions)
Although the high-frequency dielectric heating conditions can be changed as appropriate, the following conditions are preferred.

The output of the high-frequency electric field is preferably 10 W or higher, more preferably 30 W or higher, even more preferably 50 W or higher, and even more preferably 80 W or higher.
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, 1,000 W or less is even more preferable.
If the output of the high-frequency electric field is 10 W or more, it is possible to prevent the problem that the temperature is difficult to rise during the dielectric heating treatment, so it is easy to obtain good bonding strength.
If the output of the high-frequency electric field is 50,000 W or less, it is easy to prevent the problem of difficulty in temperature control due to dielectric heating treatment.

The application time of the high-frequency electric field is preferably 1 second or longer.
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 90 seconds or less. is even more preferable, and 50 seconds or less is particularly preferable.
If the application time of the high-frequency electric field is 1 second or longer, it is possible to prevent the problem that the temperature is difficult to rise during the dielectric heating treatment, so that it is easy to obtain good adhesive strength.
If the application time of the high-frequency electric field is 300 seconds or less, problems such as a decrease in manufacturing efficiency of the structure, an increase in manufacturing cost, and thermal deterioration of the adherend (X) can be easily prevented.

The frequency of the high-frequency electric field to be applied is preferably 1 kHz or higher, more preferably 1 MHz or higher, even more preferably 3 MHz or higher, even more preferably 5 MHz or higher, and 10 MHz or higher. Even more preferred.
The frequency of the high-frequency electric field to be applied 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 band of 13.56 MHz, 27.12 MHz, or 40.68 MHz allocated by the International Telecommunication Union is also used for the manufacturing method and joining method by high-frequency dielectric heating of this embodiment.

Further, when a high-frequency electric field is applied while applying pressure, the pressing pressure when applying the high-frequency is preferably 1 kPa or more as an initial setting value of the pressure applied to the high-frequency dielectric heating adhesive. It is more preferably 5 kPa or more, still more preferably 10 kPa or more, even more preferably 30 kPa or more, and even more preferably 50 kPa or more.
When a high frequency electric field is applied while applying pressure, the pressing pressure when applying the high frequency is preferably 10 MPa or less, and 5 MPa or less as an initial set value of the pressure applied to the high frequency dielectric heating adhesive. is more preferably 1 MPa or less, even more preferably 500 kPa or less, and even more preferably 100 kPa or less.
Here, the reference area for the initial set value of the pressure applied to the high-frequency dielectric heating adhesive is the smallest area among the areas of the electrodes, the adherend, and the spacer when viewed from above.

A joining method according to this embodiment will be described with reference to the drawings.
1 to 3 are schematic diagrams illustrating an example of the bonding method according to this embodiment. 1 to 3 show an example of a method of bonding a first adherend 110 and a second adherend 120 with a high-frequency dielectric heating adhesive 11 using a dielectric heating device 50. It is shown.

The dielectric heating device 50 shown in FIGS. 1 to 3 includes a first high-frequency electric field applying electrode 51, a second high-frequency electric field applying electrode 52, and a high-frequency power source 53. FIG.
The first high-frequency electric field applying electrode 51 and the second high-frequency electric field applying electrode 52 are arranged to face each other. The first high frequency electric field applying electrode 51 and the second high frequency electric field applying electrode 52 have a press mechanism. Two or more adherends arranged between the electrodes and the high-frequency dielectric heating adhesive are pressed by the press mechanism of the electrodes (the first high-frequency electric field applying electrode 51 and the second high-frequency electric field applying electrode 52) of the dielectric heating device 50. It is also possible to apply a high frequency electric field while pressurizing the .

In the dielectric heating device 50, when the first high-frequency electric field applying electrode 51 and the second high-frequency electric field applying electrode 52 constitute a pair of parallel plate electrodes, such an electrode arrangement form is called a parallel plate type. sometimes referred to as
It is also preferable to use a parallel plate type high frequency dielectric heating device for applying the high frequency electric field. In the parallel plate type high frequency dielectric heating device, the high frequency electric field penetrates the high frequency dielectric heating adhesive located between the electrodes, so that the entire high frequency dielectric heating adhesive can be heated, and the adherend (X) can be heated. and the high-frequency dielectric heating adhesive can be bonded in a short time. Further, when manufacturing a laminate as a structure, it is preferable to use a parallel plate type high-frequency dielectric heating apparatus.

A high-frequency power source 53 for applying a high-frequency electric field with a frequency of about 13.56 MHz, about 27.12 MHz, or about 40.68 MHz to each of the first high-frequency electric field applying electrode 51 and the second high-frequency electric field applying electrode 52. is connected.

FIG. 2 shows the electrodes of the dielectric heating device 50 (the first high-frequency electric field applying electrode 51 and the second high-frequency electric field applying electrode 52), the first adherend 110, the high-frequency dielectric heating adhesive 11, and the adherend (X). The second adherend 120 and the spacer 210 are arranged. The first adherend 110 does not have undulating surfaces on both the high-frequency dielectric heating adhesive 11 side and the first high-frequency electric field applying electrode 51 side. The second adherend 120 has an undulating surface on a first surface 125 and a second surface 127 opposite the first surface 125 does not have an undulating surface. As shown in FIG. 2, a spacer 210, a second adherend 120, a high-frequency dielectric heating adhesive 11, and the first adherend 110 are arranged in this order from the second high-frequency electric field applying electrode 52 side. The first surface 125 of the second adherend 120 is arranged to face the spacer 210 .

FIG. 3 shows the state after the electrodes of the dielectric heating device 50, the first adherend 110, the high-frequency dielectric heating adhesive 11, the second adherend 120, and the spacer 210 are arranged. When the spacer 210 is arranged between the second high-frequency electric field applying electrode 52 and the second adherend 120, a space 31 is formed between the undulating surface of the second adherend 120 and the spacer. . The dielectric heating device 50 can apply pressure from at least one of the first high-frequency electric field applying electrode 51 and the second high-frequency electric field applying electrode 52 . In FIG. 3 , the dielectric heating device 50 heats the first adherend 110 , the high-frequency dielectric heating adhesive 11 and the second adherend between the first high-frequency electric field applying electrode 51 and the second high-frequency electric field applying electrode 52 . The adherend 120 and the spacer 210 are pressurized in the direction of the arrow.

In FIG. 1, after arranging the electrodes of the dielectric heating device 50, the first adherend 110, the high-frequency dielectric heating adhesive 11, the second adherend 120, and the spacer 210, heating is performed by the dielectric heating device 50. It shows a state in which pressure treatment and dielectric heat treatment are performed. When pressurized by the dielectric heating device 50 , the spacer 210 deforms and follows the shape of the space 31 . Space 31 is filled with spacer 210 .

As shown in FIGS. 1 to 3, the dielectric heating device 50 uses a spacer 210 to sandwich a high-frequency dielectric heating adhesive between a first adherend 110 and a second adherend 120. 11, dielectric heat treatment. Furthermore, the dielectric heating device 50 applies pressure to the first adherend 110 and the second adherend by pressure treatment using the first high-frequency electric field applying electrode 51 and the second high-frequency electric field applying electrode 52 in addition to the dielectric heating treatment. The body 120 is joined. The bonding of the first adherend 110 and the second adherend 120 may be performed by applying a high-frequency electric field while applying pressure with electrodes of the dielectric heating device 50 . The bonding of the first adherend 110 and the second adherend 120 is performed by applying pressure from the electrode of the dielectric heating device 50, filling the space 31 with the spacer 210, and then applying a high-frequency electric field. good too.

Here, in the state in which the high-frequency electric field is applied while applying pressure by the electrodes of the dielectric heating device 50, as an initial state, the high-frequency electric field is applied at approximately the same time as the space 31 is filled with the spacer 210 by the pressure. It will be in a state where Pressurization means, for example, A.I. It refers to pressure treatment by the press mechanism of the dielectric heating device 50, or B. It refers to a pressure treatment in which pressure is applied only by the weight of the electrodes of the dielectric heating device 50 without performing pressure treatment by a press mechanism of the dielectric heating device 50, or C. It refers to a combination of pressure treatment by the press mechanism of the dielectric heating device 50 and pressure treatment by the weight of the electrode of the dielectric heating device 50 . One aspect of a state in which a high-frequency electric field is applied to the first adherend 110, the high-frequency dielectric heating adhesive 11, the spacer 210, and the second adherend 120 while being pressurized by the electrodes of the dielectric heating device 50. Examples thereof include the following aspects (E1) to (E3).

(E1): A mode in which a high-frequency electric field is applied while maintaining a deformed state of the spacer 210 by applying pressure from the electrode of the dielectric heating device 50 using a spacer made of a material that is easily elastically deformed as the spacer 210 .
(E2): A mode in which a high-frequency electric field is applied while maintaining a deformed state of the spacer 210 by using a spacer made of a material that is easily plastically deformed as the spacer 210 and applying pressure with the electrodes of the dielectric heating device 50 .
(E3): A spacer made of a material that is easily plastically deformed is used as the spacer 210. After the spacer 210 is deformed by applying pressure with the electrode of the dielectric heating device 50, the high-frequency electric field is applied while the pressure from the electrode is released. Mode of application.
In the aspect of (E3), the pressurizing process by the pressing mechanism may be canceled, and the pressing due to the weight of the electrode may be maintained.
From the viewpoint of facilitating the reuse of the spacer, the aspect of applying the high-frequency electric field while applying pressure by the electrodes of the dielectric heating device 50 is preferably the above aspect (E1).

By the joining method as described above, the structure 100 having the second adherend 120 having the undulating surface on the first surface 125 is obtained.

It should be noted that two or more adherends may be joined by pressing only with the high-frequency dielectric heating adhesive and the weight of the adherends, for example, without performing the pressure treatment by the dielectric heating device 50 . In this case, the spacer 210 may be deformed to fill the space 31 in advance before the dielectric heating treatment. For example, a material such as removable putty may be used as the spacer 210, and the spacer 210 may be deformed to fill the space in advance.

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 adhesive 11 absorbs high frequency energy. In this embodiment, even if the first surface 125 of the second adherend 120 is arranged on the side of the second high-frequency electric field applying electrode 52, the use of the spacer 210 fills the space 31 by deformation of the spacer 210. . Therefore, the high-frequency dielectric heating adhesive 11 can absorb high-frequency energy in a nearly uniform manner. As a result, the thermoplastic resin component in the high-frequency dielectric heating adhesive 11 is almost uniformly melted, and the first adherend 110 and the second adherend 120 are firmly attached even if the treatment is performed for a short period of time. can be joined to

When the high-frequency dielectric heating adhesive 11 contains a dielectric material (not shown), the dielectric material dispersed in the thermoplastic resin component as the adhesive component absorbs high-frequency energy. The dielectric material functions as a heat source, and the heat generated by the dielectric material melts the thermoplastic resin component. , the adherend 120 can be strongly bonded.

Since the first high-frequency electric field applying electrode 51 and the second high-frequency electric field applying electrode 52 have a press mechanism, they also function as a press device. Therefore, by applying pressure in the compression direction by the first high-frequency electric field applying electrode 51 and the second high-frequency electric field applying electrode 52 and heating and melting the high-frequency dielectric heating adhesive 11, the first adherend 110 and the second adherend The adherend 120 can be more strongly bonded.

An example of the joining method according to the present embodiment has been described above with reference to FIGS. 1 to 3, but the joining method according to the present embodiment is not limited to this example. In another aspect, the number of adherends is not particularly limited as long as at least one adherend (X) is used. For example, the adherend (X) may be used for both adherends. In FIGS. 1 to 3, the second adherend 120 as the adherend (X) is used as one adherend, and the first adherend having no undulating surface is used as the other adherend. A body 110 was used.
In the examples shown in FIGS. 1 to 3, as another aspect, a parallel plate type high-frequency dielectric heating device is used, and both the two adherends are the second adherend 120 as the adherend (X). may be used. In this case, any second adherend 120 is arranged with the first surface 125 facing each electrode side of the dielectric heating device 50 (the first high-frequency electric field applying electrode 51 and the second high-frequency electric field applying electrode 52). . Spacers 210 are placed between the electrodes of the dielectric heating device and the two second adherends 120, respectively, and the two second adherends 120 are bonded with the high-frequency dielectric heating adhesive 11. do.

The high-frequency dielectric heating treatment is not limited to the above-described dielectric heating device in which electrodes are arranged opposite to each other, and a lattice electrode type high-frequency dielectric heating device may be used. A grid electrode 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 electrodes of the first polarity are alternately arranged on the same plane at regular intervals. . For the sake of simplification, FIGS. 1 to 3 exemplify a mode using a dielectric heating device in which electrodes are arranged opposite to each other. Even when a lattice electrode type dielectric heating device is used, the adherend (X) can be strongly bonded in a short time.

It is also preferable to use a lattice electrode type high frequency dielectric heating device for applying a high frequency electric field. By using a lattice electrode type high-frequency dielectric heating device, bonding can be performed without being affected by the thickness of the adherend (X). Also, by using a lattice electrode type high-frequency dielectric heating device, it is possible to save energy during bonding.

When bonding with a grid electrode type dielectric heating device, the grid electrode is arranged on either the first surface side having the undulating surface of the adherend (X) or the second surface side opposite to the first surface. Then, a high frequency may be applied. Alternatively, a high-frequency electric field may be applied by arranging lattice electrodes on both the first surface side and the second surface side of the adherend (X). Further, a high-frequency electric field may be applied by arranging on the first surface side of the adherend (X), and then a grid electrode may be arranged on the second surface side to apply a high-frequency electric field.

Each member used in the joining method according to this embodiment will be described below.

<Adherend>
The adherend (X) used in the bonding method according to the present embodiment has an undulating surface on the first surface, and the undulating surface has a convex portion that is a raised portion and a concave portion that is a depressed portion. have. In the present embodiment, a relatively protruding portion of the undulating surface may be referred to as a convex portion, and a relatively depressed portion defined by the convex portion of the undulating surface may be referred to as a concave portion.

4A and 4B are cross-sectional views showing an example of an adherend used in the bonding method according to this embodiment. For example, the adherend 120B shown in FIG. 4A has an undulating surface on the first surface, and the

convex portions

121A, 121B, and 121C are raised portions of the undulating surface, The concave portion 123A, the concave portion 123B, the concave portion 123C, and the concave portion 123D are the depressed portions of the undulating surface. The cross-sectional shape of the recesses and protrusions is not limited to the rectangular shape shown in FIGS. 4A and 4B. and may have steps. Further, for example, the protruding portion of the undulating surface may be semicircular. In this case, the semicircular portion becomes a convex portion, and the recessed portions on both sides of the convex portion become concave portions. Furthermore, for example, when the recessed portion of the undulating surface is semicircular, the semicircular portion becomes a concave portion, and the raised portions on both sides of the semicircular recessed portion become convex portions.

In the adherend (X), the maximum height difference of the undulations of the undulating surface is preferably 1 mm or more, more preferably 2 mm or more, even more preferably 3 mm or more, and 4 mm or more. Even more preferable. If the maximum height difference of the undulations of the undulating surface is 1 mm or more, the effect of using the spacer to firmly bond the adherend (X) and the high-frequency dielectric heating adhesive in a short time tends to increase.
The upper limit of the height difference of the undulations of the undulating surface of the adherend is not particularly limited as long as the adherend (X) and the high-frequency dielectric heating adhesive can be firmly bonded in a short time using a spacer. The maximum height difference of the undulations of the undulating surface of the adherend may be, for example, 40 mm or less, 20 mm or less, or 10 mm or less.

The maximum height difference of the undulations of the undulating surface represents the maximum value of the height difference from the top of the projection to the bottom of the recess when the undulation surface has one projection. The top of the protrusion is the highest portion of the protrusion, and the bottom of the recess is the lowest portion of the recess. Note that, for example, in the case where the undulating surface has one raised portion or depressed portion in the shape of a single semicircle, the height difference of the undulations is the radius of the semicircle.

The maximum height difference of the undulations of the undulating surface represents the maximum value of the height difference between the projections and the recesses when the number of projections on the undulation surface is two or more. For example, referring to FIG. 4A, recess 123A, recess 123B, recess 123C, and recess 123D each have the same distance from the top T of protrusion 121C to the bottom L of recess 123D. Therefore, the maximum height difference of the undulations shown in FIG. 4A is represented by, for example, the maximum height difference D from the top T of the adjacent convex portion 121C to the bottom L of the concave portion 123D.
On the other hand, referring to FIG. 4B, for example, in the adherend 120D, the heights of the

protrusions

122A, 122B, 122C, and 122D are different, and the protrusion 122B projects the most. . In the adherend 120D, the

recesses

124A, 124B, 124C, and 124D have different depths, and the recess 124D is the most recessed. Therefore, the maximum height difference of the undulations shown in FIG. 4B is represented by the maximum height difference D from the top T of the projection 122B that protrudes the most to the bottom L of the recess 124D that sinks the most.

In the adherend (X), when the first surface of the adherend (X) is viewed in plan, the area ratio of the recesses occupying the first surface is preferably 20% or more, and 30% or more. is more preferably 40% or more, even more preferably 50% or more, and even more preferably 60% or more.
The upper limit of the area ratio of the recesses in the first surface is not particularly limited, and is preferably 90% or less, for example.
When the area ratio of the concave portions to the first surface is 20% or more, the effect of using the spacer is enhanced, and the adherend (X) can be easily and firmly bonded in a short time.

In the bonding method according to this embodiment, the material of the adherend (X) is not particularly limited. The material of the adherend may be either an organic material or an inorganic material (including a metal material, etc.), or may be a composite material of an organic material and an inorganic material.

The material of the adherend (X) is preferably an organic material. Organic materials for the adherend include, for example, plastic materials and rubber materials. Examples of plastic materials include polypropylene resin, polyethylene resin, ethylene-vinyl acetate copolymer, epoxy resin, polyurethane resin, acrylonitrile-butadiene-styrene copolymer resin (ABS resin), unhydrogenated styrene-conjugated diene copolymer. coalescence (styrene-butadiene-styrene copolymer (SBS), styrene-butadiene/butylene-styrene copolymer, styrene-isoprene copolymer, styrene-isoprene-styrene copolymer (SIS), styrene-ethylene/isoprene- styrene copolymer, etc.), hydrogenated styrene-conjugated diene copolymer (styrene-ethylene/propylene-styrene copolymer (SEPS), and styrene-ethylene/butylene-styrene copolymer (SEBS), etc.), polycarbonate resin (PC resin), polyamide resin (nylon 6 and nylon 66, etc.), polyester resin (polyethylene terephthalate (PET resin) and polybutylene terephthalate resin (PBT resin), etc.), polyacetal resin (POM resin), polymethyl methacrylate resin, and A polystyrene resin etc. are mentioned. Rubber materials include styrene-butadiene rubber (SBR), ethylene propylene rubber (EPR), butadiene rubber (BR), and silicone rubber. Also, the adherend (X) may be an organic foam material. When the material of the adherend is a thermoplastic resin, from the viewpoint of adhesion, the main composition of the thermoplastic resin contained in the adherend (X) is the thermoplastic resin (A ) is preferably the same as the main composition.

In the present specification, the term "main composition of the thermoplastic resin" means, for example, when the thermoplastic resin is a polymer, among the repeating units contained in the polymer, the repeating unit that is the most contained in the polymer. be. If 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 that is the most contained in the polymer 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 is a repeating unit (monomer unit) containing 30% by mass or more, and in one aspect, 30% by mass. It is a repeating unit that is contained in excess, and in another aspect, it is a repeating unit that is included in an amount of 40% by mass or more, and in another aspect, it is a repeating unit that is included in an amount of 50% by mass or more. Moreover, when the thermoplastic resin is a copolymer, two or more kinds of repeating units may be included most.

Examples of inorganic materials for the adherend (X) include glass materials, cement materials, ceramic materials, and metal materials. Also, the adherend (X) may be fiber reinforced plastics (FRP), which is a composite material of fibers and the plastic material described above. Plastic materials in this fiber-reinforced resin include, for example, polypropylene resin, polyethylene resin, polyurethane resin, acrylonitrile-butadiene-styrene copolymer resin (ABS resin), polycarbonate resin (PC resin), polyamide resin (nylon 6 and nylon 66, etc.). ), polyester resin (polyethylene terephthalate (PET resin) and polybutylene terephthalate resin (PBT resin), etc.), polyacetal resin (POM resin), polymethyl methacrylate resin, epoxy resin, and at least selected from the group consisting of polystyrene resin, etc. It is one kind. Examples of fibers in the fiber-reinforced resin include glass fiber, Kevlar fiber, and carbon fiber.

The adherend (X) preferably has low conductivity.

In the bonding method according to the present embodiment, when two or more adherends are bonded together using a high-frequency dielectric heating adhesive, at least one adherend among the plurality of adherends is An adherend (X) is used. The materials of the plurality of adherends are the same material or different materials.

The shape of the adherend is not particularly limited, but when the high-frequency dielectric heating adhesive according to the present embodiment is an adhesive sheet, the adherend preferably has a surface on which the adhesive sheet can be attached. A sheet-like, plate-like or block-like shape is preferred. When a plurality of adherends are to be joined together, the shapes and dimensions of the adherends may be the same or different.

<Spacer>
The material of the spacer used in the bonding method according to the present embodiment is not particularly limited as long as it is deformable and can fill the space formed by the first surface of the adherend (X) and the spacer. Materials for the spacer include, for example, rubber, clay, and putty. The rubber is not particularly limited, and includes various rubbers. When the material of the spacer is rubber, among rubbers, silicone rubber is preferable from the viewpoint that it is difficult to generate heat due to application of a high-frequency electric field, so that heat deterioration is less likely to occur, and welding to an adherend is less likely to occur. As the clay, any commonly known clay may be used, and examples thereof include silicone clay containing silicone resin. Examples of the putty include inert chemical synthetic resins and the like.

(thickness)
The thickness of the spacer is preferably 50% or more, more preferably 75% or more, with respect to the maximum height difference of the undulations of the undulation surface provided on the first surface of the adherend (X). % or more, more preferably 125% or more, even more preferably 150% or more, and even more preferably 175% or more. When the thickness of the spacer is 50% or more of the maximum height difference of the undulating surface of the adherend, the spacer can be easily embedded in the concave portions of the undulating surface.
The upper limit of the thickness of the spacer is not particularly limited as long as it can fill the space and firmly bond an adherend having an undulating surface in a short time. It may be 500% or less, 400% or less, or 300% or less of the maximum height difference of the undulations of the undulation surface of the first surface.
The thickness of the spacer represents the distance between the surface of the spacer facing the electrode side and the surface facing the adherend (X). For example, referring to FIG. 2, the thickness Z of the spacer 210 is determined by is the distance between

(dielectric properties)
The dielectric property (tan δ/ε'r) of the spacer is preferably 0.003 or less, more preferably 0.002 or less, and even more preferably 0.0010 or less. The spacer used in the bonding method according to this embodiment usually has a dielectric property of 0 or more.
(tan δ is the dielectric loss tangent at 23 ° C. and a frequency of 40.68 MHz,
ε′r is the dielectric constant at 23° C. and a frequency of 40.68 MHz. )

The smaller the dielectric property of the spacer (the closer it is to 0), the more difficult it is for the spacer to generate heat when subjected to dielectric heat treatment. more restrained. Therefore, if the dielectric property of the spacer is 0.003 or less, the spacer is less likely to generate heat when subjected to dielectric heating treatment, and the adherend having an undulating surface and the adhesive can be firmly bonded in a short time. easier to do.

The dielectric property (tan δ/ε'r) is a value obtained by dividing the dielectric loss tangent (tan δ) measured using an impedance material device or the like by the relative permittivity (ε'r) measured using an impedance material device or the like. is.
A dielectric loss tangent (tan δ) and a dielectric constant (ε′r) as dielectric properties of the spacer can be measured simply and accurately using an impedance material analyzer.
The details of the spacer measurement method are as follows. First, a test piece for spacer measurement is obtained. When the thickness of the spacer is thick, the thickness may be adjusted by cutting, polishing, or the like. The thickness of the measurement sheet is, for example, 10 μm or more and 2 mm or less. For the sheet thus obtained, using an RF impedance material analyzer E4991A (manufactured by Agilent), the dielectric constant (ε'r) and dielectric loss tangent (tan δ) were measured under the condition of a frequency of 40.68 MHz at 23 ° C. Each is measured and the value of the dielectric property (tan δ/ε'r) is calculated.

(Insulation properties)
The spacer is preferably an insulator. If the spacer is an insulator, electricity will not flow through the spacer during dielectric heating treatment, and the dielectric heating treatment will be performed in a state close to the uniformity of the high-frequency dielectric heating adhesive. It becomes easy to firmly bond the body (X) and the high-frequency dielectric heating adhesive in a short time.

In this embodiment, the insulating property of the spacer is determined by measuring the volume resistivity at a measurement voltage of 500 V according to JIS K 6911:1995. A spacer is defined as an insulator when the volume resistivity exceeds 10 ⁸ Ω·cm one minute after the start of measurement.

(Spatial followability)
In the bonding method according to the present embodiment, the space followability of the spacer is preferably 50% or more, more preferably 60% or more, and more preferably 70% or more. It is more preferable to bond to 80% or more, and it is even more preferable to bond to 80% or more. In particular, the greater the followability of the spacer to the space, the easier it is to embed the spacer in the space. For example, if the spatial followability of the spacer is 50% or more, the high-frequency dielectric heating adhesive can absorb high-frequency energy in a more uniform state, so that the adherend (X) and the adhesive can be kept together for a short time. , making it easier to join firmly.
There is no particular upper limit to the spatial followability of the spacer. The upper limit of the space followability of the spacer may be 100% or less.

Space followability FP of the spacer is represented by the following Equation 1.
FP=(S2/S1)×100 (Equation 1)
S1 is the state before the spacer follows the adherend (X) when the space (the space formed by the first surface of the adherend (X) and the spacer) is viewed from above. This is the area corresponding to the shape of the opening of the space of the body (X).
S2 is a plane view of a portion where the coloring agent is attached to the surface of the spacer that fills the space when the space is filled by deformation of the spacer by attaching the colorant to the surface inside the space. It is the area of time.

Here, the space followability of the spacer will be explained with reference to the drawings. 5A to 7B are conceptual diagrams for explaining a method of measuring spatial followability. An adherend 120C shown in FIGS. 5A to 7B is an adherend as the adherend (X). 5A, 6A, 5B, and 6B show a state in which the first surface having the undulating surface side of the adherend 120C is placed facing the spacer 210A. 5A and 6A show the state before pressurization, FIG. 5A represents a plan view seen from the second surface side of the adherend 120C, and FIG. 6A represents a cross-sectional view along AA in FIG. 5A. ing. 5B and 6B show the state after pressurization, FIG. 5B shows a plan view of the adherend 120C viewed from the second surface side, and FIG. 6B shows a cross-sectional view along the line BB in FIG. 5B. ing. The dashed lines shown in FIGS. 5A and 5B represent the positions of the recesses provided on the first surface side of the adherend 120C, the coloring agent V applied inside the recesses, and the positions of the spacers 210A. Further, as shown in FIGS. 6A and 6B, in FIGS. 5A and 5B, the coloring agent V adheres also to the bottom side of the recess forming the space 31A (that is, the inner portion surrounded by the dashed line). there is In FIGS. 5A and 5B, the illustration of the coloring agent V applied to the bottom side of the recess is omitted for convenience to show the positional relationship between the position of the adherend 120C and the position of the spacer 210A.

As shown in FIGS. 5A-6B, the adherend 120C has a first surface located on the side of the spacer 210A. The first surface of the adherend 120C has an undulating surface having concave portions and convex portions. The concave portion of the adherend 120C has a rectangular opening when viewed from the top of the first surface of the adherend 120C and a rectangular cross section when viewed from the side of the adherend 120C. That is, the first surface of the adherend 120C has a concave shape surrounded by a rectangular plane and a rectangular cross section. As shown in FIG. 6A, when the first surface of the adherend 120C and the spacer 210A are overlapped, the space 31A is formed between the recess of the adherend 120C and the spacer 210A in a non-pressurized state. is formed. The space 31A is defined by the spacer 210A and the recess of the adherend 120C.

The spatial followability FP is measured as follows. First, the coloring agent V is applied in advance to adhere to the entire interior surface of the recess forming the space 31A. The type of coloring agent V is not particularly limited. For the coloring agent V, it is preferable to use vermillion ink for stamps, for example, in order to suppress the repelling of the coloring agent V against the adherend 120C and the spacer 210A and improve the adhesion of the coloring agent V.

Next, the spacer 210A is placed facing the first surface of the adherend 120C. Then, pressure is applied to the spacer 210A toward the adherend 120C. When pressure is applied to the spacer 210A toward the adherend 120C, the spacer 210A to which the pressure is applied is deformed, and part of the spacer 210A is embedded inside the space 31A. The pressure applied to the spacer 210A is not particularly limited, and may be any pressure that makes the conformability to the space of the adherend 50% or more. An example of the pressure is the pressure applied when applying a high-frequency electric field while pressing the adherend (X) and the high-frequency dielectric heating adhesive with electrodes. The coloring agent V attached to the inner surface of the space is attached to the surface of the part of the spacer 210 embedded in the space.

FIG. 7A shows a plan view of the adherend 120C viewed from the first surface (that is, the space portion side). The adherend 120C shown in FIG. 7A is in a state before part of the spacer 210A follows the space of the adherend 120C, and before the coloring agent V is applied to the entire interior of the recess. is. FIG. 7B is a plane of the spacer 210A taken out from the space 31A after the coloring agent V is applied to the entire interior of the recess, and the spacer 210A is made to follow the adherend 120C, as viewed from the surface of the spacer 210A to which the coloring agent V is attached. represents the figure.

The area S1A and the area S1B shown in FIG. 7A are each part of the area corresponding to the shape of the opening RO of the space 31A of the adherend 120C. An area S2A and an area S2B shown in FIG. 7B are each part of the area where the colorant V attached to the inner surface of the space 31A is attached to the surface of the spacer 210A. Specifically, it is as follows. First, when the coloring agent V is attached to the inner surface of the space 31A and the interior of the space 31A is filled by deformation of the spacer 210A, the coloring agent V adheres to the surface of the spacer 210A that fills the space 31A. do. Next, the pressure for deforming the spacers 210A is released to separate the adherend 120C and the spacers 210A. After that, the portion where the coloring agent V is attached to the surface of the spacer 210A is viewed from above. A part of the area when viewed in plan is the area S2A and the area S2B. The area S2A and the area S2B respectively correspond to the substantially cross-shaped portions to which the coloring agent V is adhered, as shown in FIG. 7B.

Then, according to the above-mentioned formula 1, the spatial followability FP is expressed as a percentage obtained by dividing the total area (S2) of the areas S2A and S2B by the total area (S1) of the areas S1A and S1B. .

<Adhesive for high-frequency dielectric heating>
The high-frequency dielectric heating adhesive used in the bonding method according to this embodiment contains a thermoplastic resin (A). The high-frequency dielectric heating adhesive contains the thermoplastic resin (A) and may or may not contain a dielectric material. From the viewpoint of facilitating the enhancement of the heat generation property of the high-frequency dielectric heating adhesive, the high-frequency dielectric heating adhesive preferably contains a dielectric material. The dielectric material is not particularly limited, and may be either dielectric resin or dielectric filler. The dielectric material is preferably a dielectric filler (B), for example, from the viewpoint of less deterioration during molding and stable heat generation.

In this specification, the thermoplastic resin contained in the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment is referred to as thermoplastic resin (A), and the dielectric filler is referred to as dielectric filler (B). There is

(Thermoplastic resin (A))
The type of thermoplastic resin (A) is not particularly limited.
The thermoplastic resin (A) is, for example, polyolefin-based resin, styrene-based resin, polyacetal-based resin, polycarbonate-based resin, acrylic-based resin, polyamide-based resin, from the viewpoint of being easy to melt and having predetermined heat resistance. It is preferably at least one selected from the group consisting of polyimide-based resins, polyvinyl acetate-based resins, phenoxy-based resins, and polyester-based resins.

In the high-frequency dielectric heating adhesive used in the bonding method according to this embodiment, the thermoplastic resin (A) is preferably a polyolefin resin or a styrene resin, more preferably a polyolefin resin. If the thermoplastic resin (A) is a polyolefin-based resin or a styrene-based resin, the high-frequency dielectric heating adhesive is likely to melt when a high-frequency electric field is applied, and the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment can be easily melted. It can be easily adhered to the adherend (X).
In the present specification, polyolefin resin includes polyolefin resins having polar sites and polyolefin resins having no polar sites. is described as a polyolefin-based resin that does not have

It is also preferable that the thermoplastic resin (A) is a polyolefin resin having a polar site. The thermoplastic resin (A) may be a polyolefin resin that does not have a polar site.

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

[Polyolefin-based resin having a polar site]
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.
Further, when the high-frequency dielectric heating adhesive contains a polyolefin-based resin having a polar site as the thermoplastic resin (A), the dielectric properties are likely to be improved, and the adhesive strength to the adherend (X) is increased, which is preferable. .
The polyolefinic thermoplastic resin having a polar site may be a copolymer of an olefinic monomer and a monomer having a polar site. The polyolefinic thermoplastic resin having a polar site may also be a resin obtained by introducing a polar site into an olefinic polymer obtained by polymerization of an olefinic monomer through modification such as an addition reaction.

There are no particular restrictions on the type of olefinic monomer that constitutes the polyolefinic resin having a polar site. Examples of olefinic monomers include ethylene, propylene, butene, hexene, octene, 4-methyl-1-pentene, and the like. These olefinic monomers may be used singly or in combination of two or more.
At least one of ethylene and propylene is preferable as the olefin-based monomer from the viewpoint of excellent mechanical strength and stable adhesive properties.
The olefin-derived structural unit in the polyolefin-based resin having a polar site is preferably a structural unit derived from ethylene or propylene.

Polar sites include, for example, hydroxyl groups, carboxyl groups, vinyl acetate structures, acid anhydride structures, and the like. Examples of polar sites include acid-modified structures that are introduced into polyolefin resins by acid modification.

The acid-modified structure as a polar site is a site introduced by acid-modifying a thermoplastic resin (eg, polyolefin resin). Compounds used for acid-modifying thermoplastic resins (e.g., polyolefin resins) include unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, and unsaturated carboxylic acid esters. A carboxylic acid derivative component may be mentioned. In this specification, a polyolefin resin having an acid-modified structure may be referred to as an acid-modified polyolefin resin.

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

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

Examples of unsaturated carboxylic acid esters include methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dimethyl maleate, monomethyl maleate, dimethyl fumarate, diethyl fumarate, and dimethyl itaconate. , diethyl itaconate, dimethyl citraconate, diethyl citraconate, and esters of unsaturated carboxylic acids such as dimethyl tetrahydrophthalate anhydride.

(Dielectric filler (B))
The dielectric filler (B), which is a preferred dielectric material, will now be described.
The dielectric filler (B) is a filler that generates heat when a high frequency electric field is applied. A high-frequency electric field is an electric field whose direction is reversed at high frequencies.
The dielectric filler (B) is preferably a filler that generates heat when a high-frequency electric field with 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 upon application of a high-frequency electric field having a frequency of 13.56 MHz, 27.12 MHz, or 40.68 MHz, within a frequency range of 3 MHz or higher and 300 MHz or lower.

Dielectric filler (B) is zinc oxide, silicon carbide (SiC), anatase titanium oxide, barium titanate, barium zirconate titanate, lead titanate, potassium niobate, rutile titanium oxide, hydrated aluminum silicate, Inorganic materials having water of crystallization such as hydrated aluminosilicate of alkali metals or inorganic materials having water of crystallization such as hydrated aluminosilicates of alkaline earth metals are preferably used singly or in combination of two or more.

From the viewpoint of obtaining higher heat build-up, the dielectric filler (B) preferably contains at least one selected from the group consisting of zinc oxide, silicon carbide, barium titanate and titanium oxide. At least one selected from the group consisting of barium and titanium oxide is more preferable.

Among the dielectric fillers exemplified, there are many types, and various shapes and sizes can be selected, and the adhesive properties and mechanical properties of the high-frequency dielectric heating adhesive can be improved according to the application. Zinc oxide is more preferred. By using zinc oxide as the dielectric filler (B), a colorless adhesive for high-frequency dielectric heating can be obtained. Zinc oxide has a low density among dielectric fillers, so when the adherend (X) is bonded using a high-frequency dielectric heating adhesive containing zinc oxide as the dielectric filler (B), other dielectric fillers are included. The total weight of the structure is less likely to increase as compared with the case of using an adhesive that adheres to the structure. Zinc oxide is not too hard among ceramics, so it is less likely to damage the production equipment for high-frequency dielectric heating adhesives. Since zinc oxide is an inactive oxide, even if it is blended with a thermoplastic resin, it causes little damage to the thermoplastic resin.
In addition, 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. .

The volume content of the dielectric filler (B) in the high-frequency dielectric heating adhesive 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, and even more preferably 35% by volume or less. , 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 is improved, and the high-frequency dielectric heating adhesive and the adherend (X) are firmly bonded. Easy to join.
Since the volume content of the dielectric filler (B) in the high-frequency dielectric heating adhesive is 50% by volume or less, it is possible to prevent the strength of the adhesive from decreasing, and as a result, the bonding strength is increased by using the adhesive. can prevent a decline in Further, when the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment is an adhesive sheet, the volume content of the dielectric filler (B) in the adhesive sheet is 50% by volume or less. Flexibility can be easily obtained and toughness can be easily prevented from being lowered, so that the adhesive sheet for high-frequency dielectric heating can be easily processed into a desired shape in a subsequent step.

In addition, when the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment contains the thermoplastic resin (A) and the dielectric filler (B), the total volume of the thermoplastic resin (A) and the dielectric filler (B) In contrast, the volume content of 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) is preferably 50% by volume or less, more preferably 40% by volume or less, relative to the total volume of the thermoplastic resin (A) and the dielectric filler (B). , more preferably 35% by volume or less, and even more preferably 25% by volume or less.

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.
Since the dielectric filler (B) has a volume average particle size of 1 μm or more, the high-frequency dielectric heating adhesive exhibits high heat generation performance when a high-frequency electric field is applied, and is firmly attached to the adherend (X) in a short time. Can be glued.
Since the dielectric filler (B) has a volume average particle size of 30 μm or less, the high-frequency dielectric heating adhesive exhibits high heat generation performance when a high-frequency electric field is applied, and is firmly attached to the adherend (X) in a short time. Can be glued. Further, when the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment is an adhesive sheet, the volume average particle size of the dielectric filler (B) is 30 μm or less, so that the strength of the high-frequency dielectric heating adhesive sheet You can prevent the decline.

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 a laser diffraction/scattering method, and the volume average particle size is calculated from the results of the particle size distribution measurement according to JIS Z 8819-2:2001.

<Additive>
The high-frequency dielectric heating adhesive used in the bonding method according to this embodiment may or may not contain an additive.

When the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment contains additives, the additives include, for example, tackifiers, plasticizers, waxes, colorants, antioxidants, ultraviolet absorbers, antibacterial agents, coupling agents, viscosity modifiers, organic fillers, inorganic fillers, and the like. Organic and inorganic fillers as additives are different from dielectric materials (dielectric fillers).

Tackifiers and plasticizers can improve the melting and adhesion properties of high frequency dielectric heating adhesives.
Examples of tackifiers include rosin derivatives, polyterpene resins, aromatic modified terpene resins, hydrides of aromatic modified terpene resins, terpene phenol resins, coumarone-indene resins, aliphatic petroleum resins, aromatic petroleum resins, and aromatic and hydrides of family petroleum resins.
Plasticizers include, for example, petroleum-based process oils, natural oils, dialkyl dibasic acids, and low molecular weight liquid polymers. Petroleum-based process oils include, for example, paraffinic process oils, naphthenic process oils, and aromatic process oils. Natural oils include, for example, castor oil, tall oil, and the like. Dialkyl dibasic acids include, for example, dibutyl phthalate, dioctyl phthalate, and dibutyl adipate. Examples of low molecular weight liquid polymers include liquid polybutene and liquid polyisoprene.

When the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment contains an additive, the content of the additive in the high-frequency dielectric heating adhesive is usually based on the total amount of 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. 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.

The high-frequency dielectric heating adhesive used in the bonding method according to this embodiment preferably does not contain a solvent. According to the solvent-free high-frequency dielectric heating adhesive, the problem of volatile organic compounds (VOC) caused by the adhesive used for adhesion to the adherend (X) is less likely to occur.

The high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment preferably does not contain carbon or a carbon compound containing carbon as a main component (for example, carbon black, etc.) and a conductive substance such as metal. High-frequency dielectric heating adhesives used in the bonding method according to the present embodiment include, for example, carbon steel, α-iron, γ-iron, δ-iron, copper, iron oxide, brass, aluminum, iron-nickel alloy, iron-nickel-chromium. It is preferably free of alloys, carbon fibers and carbon black.

When the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment contains a conductive substance, the content of the conductive substance in the adhesive is independently 7 mass based on the total amount of the adhesive. % or less, more preferably 6% by mass or less, even more preferably 5% by mass or less, even more preferably 1% by mass or less, and 0.1% by mass or less. is even more preferred.
It is particularly preferable that the content of the conductive substance in the adhesive is 0% by mass.
If the content of the conductive substance in the adhesive is 7% by mass or less, it becomes easy to prevent the problem of carbonization of the bonding portion and the adherend (X) due to electrical breakdown during the dielectric heat treatment.

The total content of the thermoplastic resin (A) and the dielectric filler (B) in the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment is preferably 80% by mass or more, and 90% by mass or more. It is more preferably 93% by mass or more, even more preferably 95% by mass or more, and even more preferably 99% by mass or more.

The shape of the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment is not particularly limited, and is preferably sheet-like. That is, the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment is preferably an adhesive sheet (sometimes referred to as a high-frequency dielectric heating adhesive sheet). Since the high-frequency dielectric heating adhesive is an adhesive sheet, it is possible to further shorten the time required for the manufacturing process of the structure. The sheet-like high-frequency dielectric heating adhesive may be in the form of a frame-like sheet having openings penetrating from one surface to the other surface of the surfaces facing each other. The opening may have one, or may have two or more. The sheet-like high-frequency dielectric heating adhesive may be a sheet without the opening.

(dielectric properties)
The dielectric properties (tan δ/ε'r) of the high-frequency dielectric heating adhesive used in the bonding method according to this embodiment will be described. The high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment has a dielectric property (tan δ/ε′r) of 0.005 or more. (tan δ is the dielectric loss tangent at 23 ° C. and a frequency of 40.68 MHz,
ε′r is the dielectric constant at 23° C. and a frequency of 40.68 MHz. )

If the dielectric property of the high-frequency dielectric heating adhesive is 0.005 or more, the high-frequency dielectric heating adhesive easily generates heat when the dielectric heating treatment is performed, and the high-frequency dielectric heating adhesive and the adherend (X ) can be firmly joined in a short time.

The dielectric property of the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment is more preferably 0.008 or more, and even more preferably 0.010 or more.
If the dielectric property of the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment is 0.008 or more, the high-frequency dielectric heating adhesive is more likely to generate heat when the dielectric heating treatment is performed. It becomes easy to bond the heating adhesive and the adherend (X) firmly in a short time.

The upper limit of the dielectric properties of the high-frequency dielectric heating adhesive used in the bonding method according to this embodiment is not particularly limited. The dielectric property of the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment may be, for example, 0.1 or less, 0.08 or less, or 0.05 or less. good. The dielectric properties of the high-frequency dielectric heating adhesive may satisfy, for example, 0.005 or more and 0.1 or less.
If the dielectric property of the high-frequency dielectric heating adhesive is 0.1 or less, overheating is easily suppressed, and damage to the portion where the adherend (X) and the high-frequency dielectric heating adhesive are in contact is less likely to occur.

The method of measuring the dielectric properties (tan δ/ε'r) of the high-frequency dielectric heating adhesive is the same as the method of measuring the dielectric properties (tan δ/ε'r) of the spacer described above.
In addition, in the measurement of the dielectric properties (tan δ/ε'r) of the high-frequency dielectric heating adhesive, if it is necessary to obtain a measurement sheet for the high-frequency dielectric heating adhesive from the structure, cut it out from the structure or scrape it. A sheet for measurement with a uniform thickness is obtained by taking out the sheet. For example, a pellet-like high-frequency dielectric heating adhesive that is not formed into a sheet may be formed into a sheet using a heat press or the like to obtain a sheet for measurement.

The thickness of the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 30 μm or more, and 50 μm or more. is particularly preferred.
When the thickness of the adhesive sheet is 5 μm or more, the adhesive sheet in contact with the adherend (X) is improved in heat generation when a high frequency is applied, so that the adhesive sheet and the adherend (X) can be firmly bonded in a short time. Easy to adhere. In addition, when the adhesive sheet is bonded to the adherend (X), the adhesive sheet easily conforms to the shape of the second surface of the adherend, and adhesive strength is easily exhibited.

The upper limit of the thickness of the adhesive sheet is not particularly limited. As the thickness of the adhesive sheet increases, the weight of the entire structure obtained by bonding the adhesive sheet and the adherend (X) also increases. For this reason, the adhesive sheet preferably has a thickness within a range in which there is no practical problem in workability, handleability, or the like. Considering the practicality and moldability of the high-frequency dielectric heating adhesive sheet, the thickness of the adhesive sheet used in the bonding method according to the present embodiment is preferably 2000 μm or less, more preferably 1000 μm or less, and more preferably 600 μm. More preferably:

The adhesive sheet as the high-frequency dielectric heating adhesive is easier to handle and improves workability when bonding to the adherend (X), compared to the case of using a liquid adhesive that requires coating.

In addition, the sheet thickness and the like of the adhesive sheet used as the high-frequency dielectric heating adhesive can be appropriately controlled. Therefore, the adhesive sheet can be applied in a roll-to-roll system, and the adhesive area with the second surface of the adherend (X) and the second surface of the adherend (X) can be reduced by punching or the like. The adhesive sheet can be processed into an arbitrary area and shape according to the shape of the surface. Therefore, the adhesive sheet as an adhesive for high-frequency dielectric heating has a great advantage also from the viewpoint of the manufacturing process.

(Aspect of adhesive for high-frequency dielectric heating)
The shape of the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment is not particularly limited, and is preferably sheet-like. That is, the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment is preferably an adhesive sheet (sometimes referred to as a high-frequency dielectric heating adhesive sheet). Since the high-frequency dielectric heating adhesive is an adhesive sheet, it is possible to further shorten the time required for the manufacturing process of the structure.

In one aspect, the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment is composed of only one adhesive layer made of the high-frequency dielectric heating adhesive sheet used in the bonding method according to the present embodiment. When the high-frequency dielectric heating adhesive is a high-frequency dielectric heating adhesive sheet consisting of only one adhesive layer, the adhesive layer itself (the adhesive layer itself) corresponds to the high-frequency dielectric heating adhesive sheet. The morphology and properties of the adhesive sheet for adhesives correspond to the morphology and properties of the adhesive layer. The high-frequency dielectric heating adhesive sheet preferably consists of only a single adhesive layer. That is, the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment is preferably a high-frequency dielectric heating adhesive sheet consisting of only a single adhesive layer. As a result, the thickness of the high-frequency dielectric heating adhesive sheet can be reduced, and the high-frequency dielectric heating adhesive sheet can be easily molded.

Since the adhesive sheet for high-frequency dielectric heating may consist of only one adhesive layer with high-frequency dielectric heating adhesiveness, the terms "adhesive sheet for high-frequency dielectric heating" and "adhesive layer" are used in this specification. , in some cases can be interchanged with each other.

The high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment is not limited to the mode of the high-frequency dielectric heating adhesive sheet consisting of only one adhesive layer. In another aspect of the high-frequency dielectric heating adhesion, an adhesive layer for high-frequency dielectric heating may be provided in advance on at least one surface of the adherend.

FIGS. 8A to 8C are schematic diagrams of the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment, exemplifying a plurality of modes.

A high-frequency dielectric heating adhesive 11A shown in FIG. 8A is an adhesive sheet 12 composed of only a single adhesive layer.

The adherend 14 with a high-frequency dielectric heating adhesive shown in FIG. A heating adhesive 11A is provided integrally with the adherend 120A. The adherend 120A has a first surface and a second surface, the first surface having an undulating surface and the second surface having no undulating surface. The high-frequency dielectric heating adhesive 11A is provided in direct contact with the second surface of the adherend 120A. The adherend 14 with the high-frequency dielectric heating adhesive may be prepared by separately preparing the high-frequency dielectric heating adhesive 11A and the adherend 120A and bonding them together to form an integral body. Alternatively, the second surface of the adherend 120A may be integrated with the high-frequency dielectric heating adhesive 11A. For the adherend 120A, the same material as the material described above for the material of the adherend is used.

The adherend 16 with a high-frequency dielectric heating adhesive shown in FIG. 8C includes a high-frequency dielectric heating adhesive 11A as an adhesive layer and an adherend 110A. It is provided integrally with the adherend 110A. Neither the first surface nor the second surface of the adherend 110A has an undulating surface. The high-frequency dielectric heating adhesive 11A is provided in direct contact with the non-undulating surface of the adherend 110A. The adherend 16 with the high-frequency dielectric heating adhesive may be formed by preparing the high-frequency dielectric heating adhesive 11A and the adherend 110A and bonding them together to form an integral body. Alternatively, the flat surface of the adherend 110A may be integrated with the high-frequency dielectric heating adhesive 11A. For the adherend 110A, the same material as the material described above for the material of the adherend is used.

It should be noted that, in the placement step described above, the high-frequency dielectric heating adhesive 11A is placed on the surface of the adherend 120A or the surface of the adherend 110A opposite to the electrode-side surface. Further, when the high-frequency dielectric heating adhesive is composed of only the high-frequency dielectric heating adhesive 11A, which is a single adhesive layer, in the above-described placement step, the high-frequency dielectric heating adhesive 11A and the adherend ( X) (for example, adherend 120A) are placed respectively. On the other hand, when the high-frequency dielectric heating adhesive is provided integrally with the adherend, the adherend 14 with the high-frequency dielectric heating adhesive may be placed in the aforementioned placement step. When the adherend 16 with the high-frequency dielectric heating adhesive is used, the adherend (X) (for example, the adherend 120A) and the adherend with the high-frequency dielectric heating adhesive 16 should be arranged. In either case, the first surface of the adherend (X) is arranged facing away from the high-frequency dielectric heating adhesive 11A.

(thickness)
When the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment is an adhesive sheet consisting of only one adhesive layer, the thickness of the adhesive sheet used in the bonding method according to the present embodiment is 5 μm or more. is preferably 10 μm or more, more preferably 30 μm or more, and particularly preferably 50 μm or more.
When the thickness of the adhesive sheet is 5 μm or more, the adhesive sheet in contact with the adherend (X) is improved in heat generation when a high frequency is applied, so that the adhesive sheet and the adherend (X) can be firmly bonded in a short time. Easy to adhere. In addition, when the adhesive sheet is bonded to the adherend (X), the adhesive sheet easily follows the second surface of the adherend (X), and adhesive strength is easily exhibited.

When the adhesive sheet is an adhesive for an adherend with an adhesive for high-frequency dielectric heating, the thickness of the adhesive layer is preferably 5 µm or more, more preferably 10 µm or more, and more preferably 30 µm or more. is more preferable, and 50 μm or more is even more preferable.
In the case of an adhesive for an adherend with a high-frequency dielectric heating adhesive, if the thickness of the adhesive layer is 5 μm or more, the adhesive layer is provided on the adherend when bonding to the adherend. It is easy to follow the surface of the surface, and it becomes easy to develop adhesive strength.

The upper limit of the thickness of the adhesive sheet is not particularly limited. As the thickness of the adhesive sheet increases, the weight of the entire structure obtained by bonding the adhesive sheet and the adherend (X) also increases. For this reason, the adhesive sheet preferably has a thickness within a range in which there is no practical problem in workability, handleability, or the like. Considering the practicality and moldability of the high-frequency dielectric heating adhesive sheet, the thickness of the adhesive sheet used in the bonding method according to the present embodiment is preferably 2000 μm or less, more preferably 1000 μm or less, and more preferably 600 μm. More preferably: The upper limit of the thickness of the adhesive sheet is preferably the above value regardless of whether the adhesive sheet has a structure consisting of only one adhesive layer or a multi-layer structure consisting of a plurality of layers including an adhesive layer.

The high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment is preferably used by applying a high-frequency electric field in a so-called short wave to ultra-short wave frequency band (for example, 3 MHz or more and 300 MHz or less). When a high-frequency electric field in this frequency band is applied, heat generation is improved when a high-frequency wave is applied, because the depth that can be heated is deep. Therefore, even when the high-frequency dielectric heating adhesive is thick, the adhesive sheet and the adherend (X) are easily and firmly bonded in a short time.

(Manufacturing method of adhesive for high-frequency dielectric heating)
The high-frequency dielectric heating adhesive used in the bonding method according to this embodiment can be produced, for example, by mixing the components described above. When the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment is an adhesive sheet, for example, the components described above are premixed and kneaded using a known kneading device such as an extruder and hot rolls. , extrusion molding, calendar molding, injection molding, and casting molding.

High-frequency dielectric heating adhesives have superior water resistance and moisture resistance compared to general adhesives.

The high-frequency dielectric heating adhesive used in the bonding method according to this embodiment is locally heated by application of a high-frequency electric field. Therefore, according to the high-frequency dielectric heating adhesive used in the bonding method according to the present embodiment, it is easy to prevent the problem that the entire adherend (X) is damaged during bonding with the adherend (X).

[Modification of Embodiment]
The invention is not limited to the embodiments described above. The present invention can include modifications, improvements, and the like within the scope of achieving the object of the present invention.

In addition, in the bonding method according to the present embodiment, there is no particular limitation on the direction of pressure when the space is filled by the deformation of the spacer. The pressurizing direction is preferably, for example, along the stacking direction of the adherend (X) and the spacer, and when the adherend (X) and the spacer are stacked in the vertical direction, direction), and when the adherend (X) and the spacer are laminated and arranged in the horizontal direction, it is the direction along the lamination direction (horizontal direction). The pressure treatment may be performed by applying pressure from both sides of the adherend (X) and the spacer placed, or by fixing one of the surfaces and applying pressure from the other side. The vertical direction here refers to, for example, a direction along the direction of gravity, and the horizontal direction refers to a direction perpendicular to the direction of gravity.
In addition, in the bonding method according to the present embodiment, the press mechanism of the electrode of the high-frequency dielectric heating device was exemplified as the pressurizing means when the space is filled by the deformation of the spacer, but the pressurizing means is limited to this pressurizing means. not. The pressurizing means may be, for example, pressurization by hand, pressurization by only the weight of the electrode of a high-frequency dielectric heating device not equipped with a press mechanism, or pressurizing means of a device equipped with a press mechanism other than the high-frequency dielectric heating device. It's okay.

The present invention will be described in more detail below with reference to examples. The present invention is by no means limited to these examples.

<Production of adhesive for high-frequency dielectric heating>
A thermoplastic resin (A) and a dielectric filler (B) shown below are prepared, and weighed so that the thermoplastic resin (A) is 80% by volume and the dielectric filler (B) is 20% by volume. bottom.

Next, the thermoplastic resin (A) and the dielectric filler (B) were premixed. A material obtained by pre-mixing the thermoplastic resin (A) and the dielectric filler (B) is supplied to the hopper of a 30 mm diameter twin-screw extruder, the cylinder temperature is set to 180 ° C. or higher and 230 ° C. or lower, and the die temperature is set to 230 ° C., The premixed materials were melt kneaded. After cooling the melt-kneaded material, granular pellets were produced by cutting the material. Next, the prepared granular pellets are put into a hopper of a single-screw extruder equipped with a T-die, and a cylinder temperature of 200 ° C. and a die temperature of 200 ° C. are used to extrude a film-like melt-kneaded product from the T-die, By cooling with a cooling roll, a sheet-like high-frequency dielectric heating adhesive (high-frequency dielectric heating adhesive sheet AS1) having a thickness of 0.4 mm was produced.

(Thermoplastic resin (A))
Polypropylene resin (manufactured by Japan Polypropylene Corporation, Novatec PPMH4, polypropylene homopolymer, melting point: 165°C)

(Dielectric filler (B))
ZnO: zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd., product name “LP-ZINC11”)

(Volume average particle size of dielectric filler)
The particle size distribution of the dielectric filler was measured by a laser diffraction/scattering method. From the results of particle size distribution measurement, the volume average particle size was calculated according to JIS Z 8819-2:2001. The calculated volume average particle size of zinc oxide (ZnO) was 11 μm.

(dielectric properties)
The produced high-frequency dielectric heating adhesive sheet was cut into a size of 30 mm×30 mm. For the cut high-frequency dielectric heating adhesive sheet, a dielectric material test fixture 16453A (manufactured by Agilent) is attached to an RF impedance material analyzer E4991A (manufactured by Agilent), and a frequency of 40.68 MHz at 23 ° C. is measured by the parallel plate method. Under these conditions, the dielectric constant (ε'r) and dielectric loss tangent (tan δ) were measured. Based on the measurement results, the values of the dielectric properties (tan δ/ε'r) were calculated. The dielectric property (tan δ/ε'r) of the high-frequency dielectric heating adhesive sheet was 0.011.

<Preparation of adherend>
As adherends, a first adherend WK1 and a second adherend WK2 shown below were prepared.

(First adherend WK1)
As the first adherend WK1, a block-shaped first adherend WK1 made of polypropylene resin shown in FIGS. 9A and 9B was produced. The first adherend WK1 has a first surface having an undulating surface with recesses and protrusions, and a second surface opposite to the first surface does not have an undulating surface. 9A and 9B show schematic diagrams of the first adherend WK1 used in the examples. FIG. 9A shows a plan view of the first adherend WK1 seen from the second surface side, and FIG. 9B shows a side view of the first adherend WK1 seen from the longitudinal direction side. . The width dimension W in the lateral direction of the first adherend WK1 is 20 mm. The length L2 of the protrusions of the first adherend WK1 is 15 mm, and the length L1 of the recesses of the first adherend WK1 is 10 mm. Therefore, the length dimension in the longitudinal direction of the first adherend WK1 is 60 mm. The maximum height difference D between the convex portion and the concave portion of the first adherend WK1 is 5 mm.

(Second adherend WK2)
A sheet made of polypropylene resin was prepared as the second adherend WK2 (width 20 mm, length 60 mm, thickness 0.4 mm).

<Preparing the spacer>
As spacers, silicone rubber, putty (inert chemical synthetic resin), and polytetrafluoroethylene (PTFE) (indicated as Teflon (registered trademark) in Table 1) having thicknesses shown in Table 1 were prepared.

(dielectric properties)
The spacer was cut into pieces with a length of 30 mm and a width of 30 mm. For the cut spacer, a dielectric material test fixture 16453A (manufactured by Agilent) was attached to an RF impedance material analyzer E4991A (manufactured by Agilent), and the ratio was measured by the parallel plate method under the condition of a frequency of 40.68 MHz at 23 ° C. The dielectric constant (ε'r) and dielectric loss tangent (tan δ) were measured respectively. Based on the measurement results, the values of the dielectric properties (tan δ/ε'r) were calculated. When the thickness of the spacer exceeds 2 mm, the spacer is adjusted to a thickness of 2 mm or less by cutting or polishing before measurement.

(Insulation)
The volume resistivity of the spacer was measured according to JIS K 6911:1995. The measurement voltage was set to 500 V, and the case where the volume resistivity exceeded 1×10 ⁸ Ω·cm one minute after the start of measurement was defined as an insulator.

(Spatial followability)
A spacer used for bonding and the first adherend WK1 were used. The inner surface of the recess of the first adherend WK1 was coated with vermilion ink for a seal, and the first adherend WK1 and the spacer were arranged to face each other. Next, the surface of the spacer was pressed against the concave portion of the first adherend WK1 under the pressure conditions for high-frequency dielectric heating, which will be described later. Then, the spacer was removed from the first adherend WK1. The pressure conditions were set so that the space followability of the spacers used in Examples 1 and 2 was 80% or more.
When the space formed by the concave portion of the first adherend WK1 is viewed in plan, the opening of the space of the first adherend WK1 is shown before the spacer follows the first adherend WK1. The sum of the areas corresponding to the shapes was set to S1. S2 was the total area of the portions of the space filled with the colorant adhered to the surface of the spacer when the space was filled by deformation of the spacer. According to Equation 1 described above, the followability to the space was obtained from the percentage obtained by dividing S2 by S1.

・Evaluation Criteria for Spatial Followability A: 80% or more.
B: 50% or more and less than 80%.
F: less than 50%.

<Examples 1 to 3 and Comparative Example 1>
The high-frequency dielectric heating adhesive sheet AS1 is cut into a size of 20 mm in width and 10 mm in length, and is used as a first electrode and a second electrode of a high-frequency dielectric heating device (manufactured by Yamamoto Vinita Co., Ltd., product name "YRP-400T-A"). A spacer cut to a width of 20 mm and a length of 60 mm is placed between the two, and the first adherend WK1, the high-frequency dielectric heating adhesive sheet AS1, and the second adherend WK2 are placed on the spacer. They were stacked and arranged in this order.
Next, the spacer, first adherend WK1, high-frequency dielectric heating adhesive sheet AS1, and second adherend WK2 arranged in this way were fixed between two electrodes of a high-frequency dielectric heating device. In the fixed state, a high-frequency electric field was applied under the following high-frequency application conditions to adhere the high-frequency dielectric heating adhesive sheet to the adherend, thereby preparing a test piece for evaluation of bondability. The pressing pressure when applying a high-frequency electric field is the initial set value of the pressure applied to the adhesive sheet.
FIG. 10 is a schematic diagram showing a side surface of a test piece for bondability evaluation. As shown in FIG. 10, the high-frequency dielectric heating adhesive sheet AS1 is arranged between the first adherend WK1 and the second adherend WK2. 1, the surface of the adherend WK1 on the opposite side of the surface provided with the recess located closest to the second end E1B side, and the second end E2B side of the second adherend WK2 facing the surface. is placed between the faces of That is, the high-frequency dielectric heating adhesive sheet AS1 arranged between the first adherend WK1 and the second adherend WK2 extends from the second end E1B of the first adherend WK1 to the first It is arranged in the range up to the first protrusion toward the end E1A.

[High-frequency electric field application conditions]
Frequency: 40.68MHz
Output: 150W
Pressing pressure: 62kPa

(Evaluation of bondability)
The bonding strength was measured according to JIS Z 0237:2000. Specifically, the bonding strength is measured using a tensile tester, and the first end E1A side of the first adherend WK1 is fixed in the test piece for bonding property evaluation shown in FIG. , was measured by 180° peeling by moving the first end E2A side of the second adherend WK2 upward.
For evaluation of bondability, the time required for high-frequency dielectric heat treatment to obtain a bond strength of 1 N/20 mm or more was measured when a test piece for bondability evaluation was produced.

〔Evaluation criteria〕
A: The time required to obtain a bonding strength of 1 N/20 mm or more is less than 30 sec.
B: The time until a bonding strength of 1 N/20 mm or more is obtained is 30 sec or more and less than 60 sec.
F: Bonding strength is less than 1 N/20 mm even after high-frequency dielectric heat treatment for 60 seconds or longer.

Each example was superior in evaluation of bondability compared to Comparative Example 1. From the above results, the bonding method according to the present embodiment can firmly bond adherends having undulating surfaces in a short period of time.

Reference Signs List

11, 11A High-frequency dielectric heating adhesive 12 High-frequency dielectric heating adhesive sheet 14 High-frequency dielectric heating adherend with adhesive 16 High-frequency dielectric heating adhesive with

adherend

31, 31A Space Part 50 Dielectric heating device 51 First high-frequency electric field applying electrode 52 Second high-frequency electric field applying electrode 53 High-frequency power supply 100

Structure

110, 110A, 120, 120A, 120B, 120C, 120D ...

Adherend

121A, 121B, 121C, 122A, 122B, 122C, 122D...

Convex part

123A, 123B, 123C, 123D, 124A, 124B, 124C, 124D... Concave part 125... First surface 127... Second surface , 210, 210A... spacer, AS1... adhesive sheet, WK1... adherend, WK2... adherend, V... colorant, E1A, E2A... first end, E1B, E2B... second end.

Claims

A bonding method for bonding adherends using a high-frequency dielectric heating adhesive,
an arranging step of arranging the electrode of the dielectric heating device, the adherend and the spacer;
a high-frequency electric field application step of applying a high-frequency electric field to the high-frequency dielectric heating adhesive to bond the adherend;
The adherend has a first surface having an undulating surface,
The high-frequency dielectric heating adhesive contains a thermoplastic resin,
In the arranging step,
When the adherend and the spacer are arranged, a space is formed between the first surface of the adherend and the surface of the spacer facing the first surface,
The space is filled by deformation of the spacer,
Joining method.
The space is filled by deformation of the spacer when the electrode presses against the adherend and the spacer.
The joining method according to claim 1.
In the high-frequency electric field application step,
bonding the adherend by applying a high-frequency electric field while pressurizing the adherend and the high-frequency dielectric heating adhesive with the electrode;
The joining method according to claim 1 or 2.
In the arranging step,
respectively disposing the high-frequency dielectric heating adhesive and the adherend;
The joining method according to claim 1 or 2.
In the arranging step,
The first surface of the adherend is arranged facing away from the high-frequency dielectric heating adhesive.
The joining method according to claim 1 or 2.
In the arranging step,
disposing two or more adherends, at least one adherend being said adherend comprising said first surface;
The joining method according to claim 1 or 2.
The undulating surface of the adherend has a maximum height difference of 1 mm or more,
The joining method according to claim 1 or 2.
The undulations of the first surface of the adherend include concave portions and convex portions, and when the first surface of the adherend is viewed in plan, the area ratio of the concave portions to the first surface is 20. % or more and less than 100%,
The joining method according to claim 1 or 2.
The thickness of the spacer is 50% or more of the maximum height difference of the undulations of the undulation surface provided on the first surface of the adherend.
The joining method according to claim 1 or 2.
The spacer has a dielectric property (tan δ/ε'r) of 0.003 or less.
The joining method according to claim 1 or 2.
(tan δ is the dielectric loss tangent at 23 ° C. and a frequency of 40.68 MHz,
ε′r is the dielectric constant at 23° C. and a frequency of 40.68 MHz. )
the spacer is an insulator,
The joining method according to claim 1 or 2.
Joining is performed so that the spatial followability FP of the spacer represented by the following formula 1 is 50% or more.
The joining method according to claim 1 or 2.
FP=(S2/S1)×100 (Equation 1)
S1: an area corresponding to the shape of the opening of the space of the adherend before the spacer follows the adherend when the space of the adherend is viewed from above S2: the space When a coloring agent is attached to the inner surface of the portion and the interior of the space is filled by deformation of the spacer, a portion where the coloring agent is attached to the surface of the spacer in the portion that fills the space is viewed from above. area when
The high-frequency dielectric heating adhesive further comprises a dielectric material that generates heat when a high-frequency electric field is applied.
The joining method according to claim 1 or 2.
the dielectric material is a dielectric filler (B),
The dielectric filler (B) is at least one selected from the group consisting of zinc oxide, silicon carbide, titanium oxide and barium titanate.
The joining method according to claim 13.
The dielectric property (tan δ/ε'r) of the high-frequency dielectric heating adhesive is 0.005 or more.
The joining method according to claim 1 or 2.
(tan δ is the dielectric loss tangent at 23 ° C. and a frequency of 40.68 MHz,
ε′r is the dielectric constant at 23° C. and a frequency of 40.68 MHz. )