Bonding structure and bonding method
The bonding structure and method utilize a connecting material and plasma treatment to achieve strong chemical bonding between difficult-to-bond materials, addressing the challenge of insufficient bonding strength in existing adhesive-based methods.
Patent Information
- Application Number
- JP2023200332
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-11-28
- Publication Date
- 2025-06-09
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Existing methods for joining difficult-to-bond materials, such as those with poor compatibility or non-polar materials, often fail to ensure sufficient bonding strength when using adhesives.
A bonding structure and method that involves providing a connecting material between the difficult-to-bond materials and using plasma treatment to form hydrophilic groups, followed by chemical bonding through dehydration condensation without the use of adhesives.
This approach enables strong and reliable bonding between difficult-to-bond materials, ensuring sufficient joining strength without the need for adhesives.
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Abstract
Description
Technical Field
[0001] The present invention relates to a joining structure and a joining method capable of joining predetermined materials to each other without using an adhesive.
Background Art
[0002] Conventionally, when joining predetermined materials to each other, for example, as shown in Patent Document 1, an adhesive is used.
Prior Art Document
Patent Document
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] However, when joining difficult-to-bond materials such as materials with poor compatibility or non-polar materials, there has been a problem that sufficient bonding strength cannot be ensured when using an adhesive.
[0005] Therefore, in view of the above problems, an object of the present invention is to provide a joining structure and a joining method capable of ensuring sufficient joining strength even for difficult-to-bond materials.
Means for Solving the Problems
[0006] The object of the present invention described above is achieved by the following means. The numbers in parentheses are the reference numerals of the embodiments described later, but the present invention is not limited thereto.
[0007] The bonding structure according to claim 1 is characterized in that when bonding at least one of the materials, which is a first material (2A) made of a difficult-to-bond material, to a second material (3A), a connecting material (4A) is provided between the first material (2A) and the second material (3A), and the first material (2A) and the second material (3A) are bonded through the connecting material (4A) by an adhesive-free bonding method.
[0008] The bonding method according to claim 2, when bonding a first material (2C) to a second material (3C), performs plasma treatment on the surfaces (2Ca, 3Ca) of the first material (2C) and the second material (3C) to break the bonds on the surfaces (2Ca, 3Ca) of the first material (2C) and the second material (3C) and form hydrophilic groups (see FIGS. 6(a) - (b)), superposes the surfaces (2Ca) of the first material (2C) and (3Ca) of the second material where the hydrophilic groups are formed in an air atmosphere (see FIG. 6(c)), and then applies a predetermined pressure in the air atmosphere until a chemical reaction occurs between the surface (2Ca) of the first material (2C) and the surface (3Ca) of the second material to bring the surface (2Ca) of the first material (2C) and the surface (3Ca) of the second material closer, and chemically bonds them by covalent bonds through dehydration condensation (see FIGS. 6(d) - (e)).
[0009] The bonding method according to claim 3, when bonding a first material (2A) to a second material (3A) by providing a connecting material (4A) between the first material (2A) and the second material (3A), performs plasma treatment on the surfaces (2Aa, 4Aa) of the first material (2A) and the connecting material (4A) to break the bonds on the surfaces (2Aa, 4Aa) of the first material (2A) and the connecting material (4A) and form hydrophilic groups (see FIGS. 5(a) - (b)), The step of overlapping the surface (2Aa) of the first material (2A) on which the hydrophilic group is formed and the surface (4Aa) of the connecting material (4A) in an air atmosphere (see FIGS. 5(c) to (d)); By performing plasma treatment on the surface (10Ba) of the intermediate material (10B) obtained by overlapping the surface (2Aa) of the first material (2A) and the surface (4Aa) of the connecting material (4A) and the surface (3Aa) of the second material (3A), the bond between the surfaces (10Ba, 3Aa) of the intermediate material (10B) and the second material (3A) is cut, and a hydrophilic group is formed (see FIGS. 5(e) to (f)); The surface (10Ba) of the intermediate material (10B) on which the hydrophilic group is formed and the surface (3Aa) of the second material (3A) are overlapped in an air atmosphere (see FIGS. 5(g) to (h)), and then, in an air atmosphere, a predetermined pressure is applied until a chemical reaction occurs between the surface (10Ba) of the intermediate material (10B) and the surface (3Aa) of the second material (3A) at a distance where a chemical reaction occurs, thereby bringing the surface (10Ba) of the intermediate material (10B) and the surface (3Aa) of the second material (3A) closer to each other, and chemically bonding them by covalent bonding by causing dehydration condensation, (see FIGS. 5(i) to (j)), and is characterized by comprising.
[0010] The bonding method according to claim 4 is characterized in that, in the bonding method according to claim 2 or 3, water vapor is introduced when performing the plasma treatment.
[0011] The bonding method according to claim 5 is characterized in that, in the bonding method according to claim 2 or 3, heating is performed when applying the predetermined pressure.
Advantages of the Invention
[0012] Next, the effects of the present invention will be described with reference numerals in the drawings. Note that the reference numerals in parentheses are those of the embodiments described later, but the present invention is not limited thereto.
[0013] According to the invention of claim 1, by means of the connecting material (4A), the first material (2A) and the second material (3A) can be firmly joined, so that even for difficult-to-bond materials, sufficient bonding strength can be ensured.
[0014] According to the invention of claim 2, it is not necessary to use an adhesive, and furthermore, due to chemical bonding, strong bonding between the first material (2C) and the second material (3C) becomes possible. Therefore, even for difficult-to-bond materials, sufficient bonding strength can be ensured.
[0015] According to the invention of claim 3, it is not necessary to use an adhesive, and furthermore, due to chemical bonding, by providing a connecting material (4A) between the first material (2A) and the second material (3A), strong bonding between the first material (2A) and the second material (3A) becomes possible. Therefore, even for difficult-to-bond materials, sufficient bonding strength can be ensured.
[0016] According to the invention of claim 4, the formation of hydrophilic groups can be promoted.
[0017] According to the invention of claim 5, the dehydration condensation reaction can be promoted.
Brief Description of the Drawings
[0018]
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Mode for Carrying Out the Invention
[0019] Hereinafter, an embodiment of the joint structure according to the present invention will be specifically described with reference to the drawings. In the following description, when indicating the up, down, left, and right directions, it shall refer to the up, down, left, and right as viewed from the front shown in the drawings.
[0020] <Description of the Joint Structure> The joint structure according to the present embodiment can ensure sufficient joint strength even for a difficult-to-bond material. Specifically, as shown in Fig. 1(a), the joint structure 1A is composed of a first material 2A, a second material 3A, and a connecting material 4A. Hereinafter, each component will be described in detail. Note that at least one of the first material 2A and the second material 3A is formed of a difficult-to-bond material.
[0021] As shown in Fig. 1(a), the first material 2A is formed in a horizontally long rectangular shape, and examples of the material include polydimethylsiloxane (PDMS).
[0022] As shown in Fig. 1(a), the second material 3A is formed in a horizontally long rectangular shape, and examples of the material include glass and acrylonitrile-butadiene-styrene copolymer (ABS).
[0023] As shown in Fig. 1(a), the connecting material 4A is formed in a rectangular shape, and examples of the material include polycarbonate (PC), AS (ABS alloy material), acrylonitrile-butadiene-styrene copolymer (ABS), polypropylene (PP), glass, polyurethane (PU), polyimide (PI), and aluminum (Al).
[0024] Thus, the joining structure 1A configured as described above is joined, as shown in Fig. 1(a), by a conventionally well-known joining method that does not use an adhesive such as ultrasonic bonding, with the right side surface of the first material 2A joined to the left side surface of the connecting material 4A and the left side surface of the second material 3A joined to the right side surface of the connecting material 4A.
[0025] Therefore, in this way, by passing through the connecting material 4A, the first material 2A and the second material 3A can be firmly joined. Therefore, even for difficult-to-bond materials, sufficient joining strength can be ensured.
[0026] In addition, in this embodiment, when configuring the joining structure 1A, an example is shown in which the right side surface of the first material 2A is joined to the left side surface of the connecting material 4A and the left side surface of the second material 3A is joined to the right side surface of the connecting material 4A, but it is not limited to this. For example, as in the joining structure 1B shown in Fig. 1(b), the lower surface of the first material 2A may be joined to the upper surface of the connecting material 4A and the upper surface of the second material 3A may be joined to the lower surface of the connecting material 4A. That is, any configuration may be used as long as the first material 2A and the second material 3A can be joined via the connecting material 4A.
[0027] On the other hand, if it is not necessary to provide the connecting material 4A, it can also be configured as in the joining structure 1C shown in Fig. 2(a) and the joining structure 1D shown in Fig. 2(b). In this regard, when explained in detail below, the joining structure 1C shown in Fig. 2(a) and the joining structure 1D shown in Fig. 2(b) are composed of the first material 2C and the second material 3C.
[0028] As shown in Fig. 2(a) and (b), the first material 2C is formed in a horizontally long rectangular shape, and examples of the material include polycarbonate (PC), acrylonitrile-butadiene-styrene copolymer (ABS), polydimethylsiloxane (PDMS), polypropylene (PP), fluorosilicone rubber (FVMQ), polyurethane (PU), acrylic (PMMA), polyethylene (PE), polyimide (PI), aluminum (Al), etc.
[0029] As shown in Figs. 2(a) and (b), the second material 3C is formed in a horizontally long rectangular shape. Examples of the material include polydimethylsiloxane (PDMS), acrylonitrile-butadiene-styrene copolymer (ABS), polyamide (PA), polyethylene naphthalate (PEN), polycarbonate (PC), polyetherimide (PEI), ethylene propylene rubber (EPDM), polyurethane (PU), acrylic (PMMA), polyethylene (PE), and the like.
[0030] Thus, in the joining structure 1C shown in Fig. 2(a) configured as described above, the right side surface of the first material 2C and the left side surface of the second material are joined by a conventionally well-known joining method such as ultrasonic bonding without using an adhesive. And in the joining structure 1D shown in Fig. 2(b), the lower surface of the first material 2C and the upper surface of the second material are joined by a conventionally well-known joining method such as ultrasonic bonding without using an adhesive.
[0031] <Explanation of the manufacturing method of the joining structure> By the way, as a method for manufacturing the joining structures 1A to 1D described above, a conventionally well-known joining method such as ultrasonic bonding without using an adhesive was exemplified, but it is preferable to manufacture by the novel manufacturing method shown below. This will be specifically described below.
[0032] First, prepare a vacuum plasma device 5 as shown in Fig. 3. This vacuum plasma device 5 includes a chamber 5a whose interior is vacuum as shown in Fig. 3, and the first materials 2A, 2C, the second materials 3A, 3C, and the connecting material 4A are placed in this chamber 5a. Then, by applying an alternating voltage 5b to the chamber 5a, plasma is generated to perform plasma treatment on the surfaces of the first materials 2A, 2C, the second materials 3A, 3C, and the connecting material 4A. Examples of the introduction gas 5c introduced into the chamber 5a shown in Fig. 3 include nitrogen and water vapor.
[0033] By the way, the reason for performing plasma treatment on the surfaces of the first materials 2A and 2C, the second materials 3A and 3C, and the connecting material 4A is as follows. This will be specifically described with reference to FIG. 4. In FIG. 4, as a specific example, the first material 2C and the second material 3C are illustrated, and further, the case where polydimethylsiloxane (PDMS) is used as the material of the first material 2C and the second material 3C will be described as an example.
[0034] As shown in FIG. 4(a), by irradiating the surface 2Ca of the first material 2C made of polydimethylsiloxane (PDMS) and the surface 3Ca of the second material 3C made of polydimethylsiloxane (PDMS) with plasma PL, the molecular structure is modified. That is, by modifying the surface 2Ca of the first material 2C and the surface 3Ca of the second material 3C, the surface bonds (in the figure, -CH 3 ) are cleaved. As a result, as shown in FIG. 4(b), hydrophilic groups (in the figure, -OH) are formed on the surface 2Ca of the first material 2C and the surface 3Ca of the second material 3C.
[0035] Next, as shown in FIG. 4(b), the first material 2C and the second material 3C after the plasma treatment for forming hydrophilic groups (in the figure, -OH) on the surface 2Ca of the first material 2C and the surface 3Ca of the second material 3C are taken out from the chamber 5a shown in FIG. 3. Then, the surface 2Ca of the first material 2C and the surface 3Ca of the second material 3C are brought close to each other by applying a predetermined pressure to a distance at which a chemical reaction occurs in an air atmosphere as shown in FIG. 4(c), and are chemically bonded by covalent bonds by causing dehydration condensation.
[0036] Thus, in this way, it is not necessary to use an adhesive, and furthermore, since they are chemically bonded, a strong bond is possible. Therefore, even for a difficult-to-bond material, sufficient bonding strength can be ensured.
[0037] Here, in more detail, a method for manufacturing the above-described bonding structures 1A to 1D will be described with reference to FIGS. 5 and 6. Note that since the bonding structures 1A and 1B differ only in the bonding location of the connecting material 4A, only the method for manufacturing the bonding structure 1B will be described using FIG. 5. And since the bonding structures 1C and 1D differ only in the bonding location, only the method for manufacturing the bonding structure 1D will be described using FIG. 6.
[0038] In manufacturing the bonding structure 1B, first, as shown in FIG. 5(a), the first material 2A and the connecting material 4A are placed in the chamber 5a. Then, in this state, the inside of the chamber 5a is evacuated, and as shown in FIG. 5(b), plasma PL is irradiated to perform plasma treatment on the surface 2Aa of the first material 2A (see FIG. 5(c)) and the surface 4Aa of the connecting material 4A (see FIG. 5(c)). As a result, as described above, hydrophilic groups are formed on the surface 2Aa of the first material 2A (see FIG. 5(c)) and the surface 4Aa of the connecting material 4A (see FIG. 5(c)). Note that as the introduction gas 5c introduced into the chamber 5a shown in FIG. 3, it is preferable to introduce water vapor. This is because the formation of hydrophilic groups is promoted.
[0039] Next, the first material 2A and the connecting material 4A that have undergone the above treatment are taken out of the chamber 5a, and as shown in FIG. 5(c), in an air atmosphere, the surface 2Aa of the first material 2A on which hydrophilic groups are formed and the surface 4Aa of the connecting material 4A on which hydrophilic groups are formed are overlapped and temporarily bonded. As a result, the intermediate material 10B shown in FIG. 5(d) is manufactured.
[0040] Next, as shown in FIG. 5(e), a second material 3A and an intermediate material 10B are placed in the chamber 5a. In this state, the inside of the chamber 5a is evacuated, and as shown in FIG. 5(f), plasma PL is irradiated to perform plasma treatment on the surface 3Aa of the second material 3A (see FIG. 5(g)) and the surface 10Ba of the intermediate material 10B (see FIG. 5(g)). As a result, as described above, hydrophilic groups are formed on the surface 3Aa of the second material 3A (see FIG. 5(g)) and the surface 10Ba of the intermediate material 10B (see FIG. 5(g)). As the introduction gas 5c introduced into the chamber 5a shown in FIG. 3, it is preferable to introduce water vapor. This is because the formation of hydrophilic groups is promoted.
[0041] Next, the second material 3A and the intermediate material 10B that have undergone the above treatment are taken out of the chamber 5a, and as shown in FIG. 5(g), in an air atmosphere, the surface 3Aa of the second material 3A on which hydrophilic groups are formed and the surface 10Ba of the intermediate material 10B on which hydrophilic groups are formed are overlapped and temporarily bonded. As a result, the state shown in FIG. 5(h) is obtained.
[0042] Next, the material in the state shown in FIG. 5(h) is sandwiched between the upper press plate 6A and the lower press plate 6B shown in FIG. 5(i), and a predetermined pressure is applied. As a result, the surface 3Aa of the second material 3A and the surface 10Ba of the intermediate material 10B are brought closer to each other to a distance at which a chemical reaction occurs between the surface 3Aa of the second material 3A and the surface 10Ba of the intermediate material 10B, and dehydration condensation occurs to chemically bond them by a covalent bond. When applying a predetermined pressure, it is preferable to heat. This is because the dehydration condensation reaction can be promoted.
[0043] Thus, by performing such treatment, the bonding structure 1B shown in FIG. 5(j) is manufactured. In addition, when manufacturing the bonding structure 1A shown in FIG. 1(a), the same treatment as above is performed, so the description is omitted.
[0044] In manufacturing the joining structure 1D, first, as shown in Fig. 6(a), a first material 2C and a second material 3C are placed in the chamber 5a. Then, in this state, the inside of the chamber 5a is evacuated, and as shown in Fig. 6(b), plasma PL is irradiated to perform plasma treatment on the surface 2Ca of the first material 2C (see Fig. 6(c)) and the surface 3Ca of the second material 3C (see Fig. 6(c)). As a result, as described above, hydrophilic groups are formed on the surface 2Ca of the first material 2C (see Fig. 6(c)) and the surface 3Ca of the second material 3C (see Fig. 6(c)). Note that as the introduction gas 5c introduced into the chamber 5a shown in Fig. 3, it is preferable to introduce water vapor. This is because the formation of hydrophilic groups is promoted.
[0045] Next, the first material 2C and the second material 3C that have undergone the above treatment are taken out of the chamber 5a, and as shown in Fig. 6(c), in an air atmosphere, the surface 2Ca of the first material 2C on which hydrophilic groups are formed and the surface 3Ca of the second material 3C on which hydrophilic groups are formed are overlapped and temporarily bonded. Then, the temporarily bonded materials are sandwiched between the upper pressing plate 6A and the lower pressing plate 6B shown in Fig. 6(d), and a predetermined pressure is applied. As a result, the surface 2Ca of the first material 2C and the surface 3Ca of the second material 3C are brought closer to each other to a distance at which a chemical reaction occurs between the surface 2Ca of the first material 2C and the surface 3Ca of the second material 3C, and they are chemically bonded by a covalent bond by causing dehydration condensation. Note that when applying a predetermined pressure, it is preferable to heat. This is because the dehydration condensation reaction can be promoted.
[0046] Thus, by performing such treatment, the joining structure 1D shown in Fig. 6(e) is manufactured. Note that in manufacturing the joining structure 1C shown in Fig. 2(a), the same treatment as above is performed, so the description is omitted.
[0047] Therefore, according to the novel manufacturing method described above, it is not necessary to use an adhesive, and furthermore, since it is chemically joined, strong joining is possible. Therefore, even for difficult-to-bond materials, sufficient joining strength can be ensured.
[0048] <Description of Experimental Examples> Here, in order to confirm the above content, the inventors conducted the following experiments. Note that the experimental examples shown below are merely examples and are not limited thereto.
[0049] First, experiments were conducted to manufacture the bonding structure 1A shown in FIG. 1(a) and the bonding structure 1B shown in FIG. 1(b). As the material of the first material 2A, polypropylene (PP) was prepared. As the material of the second material 3A, glass was prepared. As the material of the connecting material 4A, polydimethylsiloxane (PDMS) was prepared. Then, the manufacturing was carried out as described with reference to FIG. 5. The output conditions of the plasma PL were 10 W / 30 s / 50 Pa. As the predetermined pressure, it was carried out at 1.0 MPa / 300 s without heating. Also, as the introduced gas 5c, water vapor was introduced.
[0050] As a result of the above, a strong bond could be confirmed without using an adhesive.
[0051] Next, as the material of the first material 2A, polyimide (PI) was prepared. As the material of the second material 3A, glass was prepared. As the material of the connecting material 4A, polydimethylsiloxane (PDMS) was prepared. Then, the manufacturing was carried out as described with reference to FIG. 5. The output conditions of the plasma PL were 10 W / 30 s / 50 Pa. As the predetermined pressure, it was carried out at 1.0 MPa / 300 s without heating. Also, as the introduced gas 5c, nitrogen was introduced.
[0052] As a result of the above, a strong bond could be confirmed without using an adhesive.
[0053] Next, experiments were conducted to manufacture the bonding structures 1C shown in Fig. 2(a) and 1D shown in Fig. 2(b). As the material of the first material 2C, acrylonitrile-butadiene-styrene copolymer (ABS) was prepared, and as the material of the second material 3C, polyamide (PA) was prepared. Then, the manufacturing was carried out as described with reference to Fig. 6. The output conditions of the plasma PL were 10 W / 30 s / 50 Pa. As the predetermined pressure, heating was performed at 100 °C and it was carried out at 1.0 MPa / 300 s. Also, as the introduced gas 5c, water vapor was introduced.
[0054] As a result of the above, strong bonding could be confirmed without using an adhesive.
[0055] Next, as the material of the first material 2C, polypropylene (PP) was prepared, and as the material of the second material 3C, polydimethylsiloxane (PDMS) was prepared. Then, the manufacturing was carried out as described with reference to Fig. 6. The output conditions of the plasma PL were 10 W / 30 s / 50 Pa. As the predetermined pressure, it was carried out at 1.0 MPa / 300 s without heating. Also, as the introduced gas 5c, water vapor was introduced.
[0056] As a result of the above, strong bonding could be confirmed without using an adhesive.
[0057] Next, as the material of the first material 2C, polypropylene (PP) was prepared, and as the material of the second material 3C, ethylene propylene rubber (EPDM) was prepared. Then, the manufacturing was carried out as described with reference to Fig. 6. The output conditions of the plasma PL were 10 W / 30 s / 50 Pa. As the predetermined pressure, heating was performed at 100 °C and it was carried out at 1.0 MPa / 300 s. Also, as the introduced gas 5c, nitrogen and water vapor were introduced at a ratio of 1:9.
[0058] As a result of the above, strong bonding could be confirmed without using an adhesive. In the case of the EPDM sponge, bonding is possible by lightly fusing the surface to improve flatness.
[0059] Next, polypropylene (PP) was prepared as the material of the first material 2C, and polyethylene (PE) was prepared as the material of the second material 3C. Then, the manufacturing was carried out as described with reference to FIG. 6. The output conditions of the plasma PL were 10 W / 30 s / 50 Pa. As the predetermined pressure, the upper press plate 6A on the side of the first material 2C was heated to 100° C., and the lower press plate 6B on the side of the second material 3C was set to 80° C. and heated, and it was carried out at 1.0 MPa / 300 s. Further, nitrogen was introduced as the introduced gas 5c.
[0060] As a result of the above, a strong bond could be confirmed even without using an adhesive.
[0061] Therefore, from the above experimental results, it was confirmed that according to the novel manufacturing method, sufficient bonding strength can be ensured even for difficult-to-bond materials.
[0062] <Description of Modification Example> Note that the shapes and the like shown in this embodiment are merely examples, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims. The shapes of the bonding structures 1A to 1D shown in this embodiment are merely examples, and can be changed to various shapes.
[0063] Further, in this embodiment, when applying a predetermined pressure, an example of applying the pressure by sandwiching between the upper press plate 6A and the lower press plate 6B was shown, but it is not limited thereto, and the pressure may be applied by a human finger. However, the higher the pressure, the stronger the bonding strength.
Industrial Applicability
[0064] By the way, the bonding structures 1A to 1D in this embodiment have been described only from the viewpoint of bonding. From the viewpoint of peeling, if the first materials 2A and 2C, the second materials 3A and 3C, and the connecting material 4A are combined to show a failure mode of more than cohesive failure, peeling is also possible. Therefore, it can be applied to a wide range of industries such as medical, in-vehicle, and electronic components.
Explanation of Reference Numerals
[0065] 1A to 1D joining structure 2A, 2C First material 2Aa, 2Ca (Surface of the first material) 3A, 3C Second material 3Aa, 3Ca (Surface of the second material) 4A Connecting material 4Aa (Surface of the connecting material) 10B Intermediate material 10Ba (Surface of the intermediate material)
Claims
1. When joining a first material in which at least one of the materials is a difficult-to-bond material and a second material, a connecting material is provided between the first material and the second material, and the first material and the second material are joined via the connecting material by an adhesive-free bonding method, thereby forming a joined structure.
2. When joining a first material and a second material, performing plasma treatment on the surfaces of the first material and the second material to cut the bonds on the surfaces of the first material and the second material and form hydrophilic groups; superposing the surfaces of the first material and the second material on which the hydrophilic groups are formed in an air atmosphere, and then applying a predetermined pressure in the air atmosphere to bring the surfaces of the first material and the second material closer to each other by a distance at which a chemical reaction occurs between the surfaces of the first material and the second material, and chemically bonding them by covalent bonding by causing dehydration condensation.
3. By providing a connecting material between the first material and the second material, when joining the first material and the second material, performing plasma treatment on the surfaces of the first material and the connecting material to cut the bonds on the surfaces of the first material and the connecting material and form hydrophilic groups; superposing the surfaces of the first material and the connecting material on which the hydrophilic groups are formed in an air atmosphere; performing plasma treatment on the surface of the intermediate material formed by superposing the surfaces of the first material and the connecting material and the surface of the second material to cut the bonds on the surfaces of the intermediate material and the second material and form hydrophilic groups; superposing the surfaces of the intermediate material and the second material on which the hydrophilic groups are formed in an air atmosphere, and then applying a predetermined pressure in the air atmosphere to bring the surfaces of the intermediate material and the second material closer to each other by a distance at which a chemical reaction occurs between the surfaces of the intermediate material and the second material, and chemically bonding them by covalent bonding by causing dehydration condensation.
4. The bonding method according to claim 2 or 3, wherein water vapor is introduced when performing the plasma treatment.
5. The bonding method according to claim 2 or 3, wherein heating is performed when applying the predetermined pressure.
Citation Information
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