Welding method and welded body

Abstract

To laser weld dissimilar materials.SOLUTION: A welding method welds a first member and a second member using a laser beam. The first member contains an inorganic material, and the second member contains an ethylene-vinyl alcohol copolymer resin. A transmittance of a laser beam wavelength of the first member is lower than a transmittance of a laser beam wavelength of the second member. In the welding method, the laser beam is radiated to a contact portion between the first member and the second member so as to pass the second member, to weld the first member and the second member.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a welding method and a welded article. [Background technology]

[0002] Patent Document 1 discloses a laser welding resin composition for forming a structure in which an inorganic material selected from metal, ceramic, glass, and composites thereof is directly bonded to a resin by laser welding, the laser welding resin composition comprising a polyolefin resin containing a polar group. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-208296 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been an increasing need to join different materials, such as inorganic materials such as glass and resin materials, or metal materials and resin materials. This is because it is necessary to flexibly combine materials taking into account the characteristics of each material depending on the application to be used. Conventionally, methods using adhesives or fasteners such as screws have been known for joining different materials, such as the combination of inorganic materials such as glass and resin materials, or metal materials and resin materials. Joining materials using adhesives or fasteners has problems such as the adhesive being liquid and difficult to handle, taking time for the adhesive to harden, and fasteners limiting miniaturization and thinning. There is a demand for joining materials without using adhesives or screws.

[0005] A laser welding method using a laser is known as a method for joining dissimilar materials without using adhesives, screws, etc. However, laser welding of dissimilar materials has a problem in that it is difficult to weld the materials together with high strength because the materials have different physical properties, such as their melting points or molecular structures.

[0006] Patent Document 1 discloses a method of laser welding a resin material and an inorganic material using a polyolefin resin material containing a polar group. However, there is still room for further study in firmly joining different materials using laser welding.

[0007] The present disclosure has been devised in view of the above-mentioned conventional situation, and has an object to laser welding dissimilar materials. [Means for solving the problem]

[0008] The present disclosure provides a method for welding a first member and a second member using laser light, the first member including an inorganic material, the second member including an ethylene-vinyl alcohol copolymer resin, the transmittance of the first member at a wavelength of the laser light being lower than the transmittance of the second member at a wavelength of the laser light, and the laser light is irradiated to a contact portion between the first member and the second member so as to pass through the second member, thereby welding the first member and the second member.

[0009] The present disclosure also provides a welded body obtained by a method of welding a first member which is an inorganic material and a second member which is an ethylene-vinyl alcohol copolymer resin using laser light, wherein the transmittance of the first member at a wavelength of the laser light is lower than the transmittance of the second member at a wavelength of the laser light, and the welded body is obtained by irradiating the laser light to an abutting portion between the first member and the second member so that the laser light passes through the second member, and welding the first member and the second member. Effect of the Invention

[0010] According to the present disclosure, dissimilar materials can be laser welded together. [Brief description of the drawings]

[0011] [Figure 1] Front view of joined resin materials [Diagram 2] AA cross section of joined resin materials [Diagram 3] FIG. 1 is a diagram showing a welded body of dissimilar materials according to the present embodiment. [Figure 4] BB cross-sectional view of the welded body according to the present embodiment. [Diagram 5] FIG. 1 is a diagram illustrating an example in which multiple sheets of transparent material are fused to an absorptive material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, with reference to the drawings as appropriate, an embodiment specifically disclosing the welding method and welded body according to the present disclosure will be described in detail. However, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters and duplicated description of substantially the same configuration may be omitted. This is to avoid the following description becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. Note that the attached drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0013] In this specification, the use of "to" indicating a numerical range means that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0014] First, a conventional method for laser welding resin materials together will be described with reference to Figures 1 and 2. Figure 1 is a front view of the joined resin materials. Figure 2 is an AA cross-sectional view of the joined resin materials. Figures 1 and 2 use a transparent material 10 and an absorbing material 11, which are rectangular parallelepiped planar members, as an example to describe a conventional method for laser welding resin materials together.

[0015] The welded body 1 shown in Fig. 1 is a welded body in which a transparent material 10 is placed on an absorbing material 11, and a laser beam LA (see Fig. 2) is irradiated from the transparent material 10 to weld an area P1. The axis parallel to the longitudinal direction of an opposing surface 12, which is the surface of the outer circumferential surface of the transparent material 10 that faces the surface that abuts against the absorbing material 11, is defined as the Y axis. The axis perpendicular to the Y axis and parallel to the lateral direction of the opposing surface 12 is defined as the X axis. The axis perpendicular to both the X axis and the Y axis is defined as the Z axis. These expressions regarding directions are used for convenience of explanation and are not intended to limit the posture of the structure during actual use. The same applies to other drawings.

[0016] The laser light LA ​​is irradiated from the transmissive material 10 to the absorbing material 11 and moved in the X-axis direction on the region P1, whereby the transmissive material 10 and the absorbing material 11 are welded together.

[0017] FIG. 2 shows an AA cross-sectional view of the welded body 1 shown in FIG. 1. Both the transmitting material 10 and the absorbing material 11 are thermoplastic resin materials. The transmitting material 10 is a material having a high transmittance of the wavelength of the irradiated laser light LA. The transmittance of the transmitting material 10 at the wavelength of the laser light LA ​​may be higher than the transmittance of the absorbing material 11 as long as the absorbing material 11 is irradiated with the laser light LA ​​of sufficient power, and the design can be appropriately changed depending on the thickness of the transmitting material 10. The absorbing material 11 is a thermoplastic resin material to which an additive that absorbs the laser light LA ​​is added and has a low transmittance at the wavelength of the laser light LA. Here, low transmittance means that the power of the laser light LA ​​irradiated to the absorbing material 11 can be sufficiently absorbed. In other words, the transmittance of the absorbing material 11 can be appropriately set and changed depending on the power of the laser light LA ​​per unit area of ​​the irradiated surface or the moving speed of the laser light LA.

[0018] In laser welding, diode lasers or YAG lasers emitting near-infrared light of approximately 800 nm to 1200 nm are typically used.

[0019] A part of the surface of the transparent material 10 and a part of the surface of the absorbing material 11 come into contact with each other. In the example shown in FIG. 2, one of the outer peripheral surfaces of the transparent material 10 and the absorbing material 11 come into contact with each other. The transparent material 10 and the absorbing material 11 are irradiated with the laser light LA ​​from the transparent material 10 side. Here, "contact" means that the materials come into physical contact with each other, and indicates that the "transparent material" and the "absorbing material" in this specification are in direct contact with each other. The physical contact between the materials means that the objects come into direct contact with each other and are in contact with each other in a butted state. Furthermore, the meaning of "direct contact" may mean that a part of the material may be in (partial) contact, so it goes without saying that it may be surface contact, line contact, or point contact.

[0020] The laser light LA ​​passes through the transmissive material 10 and is irradiated to the contact surface between the transmissive material 10 and the absorbing material 11. The power of the laser light LA ​​is absorbed by the absorbing material 11 and converted into heat at the contact surface, and when the temperature of the contact surface exceeds the melting point, a part of the absorbing material 11 (region P2) melts.

[0021] Due to heat conduction from the molten absorbing material 11, a portion of the transmitting material 10 (region P1) melts.

[0022] When the irradiation of the laser beam LA is stopped or when the laser beam LA moves away from the regions P1, P2, the molten regions P1, P2 are cooled and solidified, and are joined together, whereby the transmissive material 10 and the absorbing material 11 are laser welded together.

[0023] In this way, by using laser welding, it is possible to join two materials of the same type, such as resin materials, without using adhesives or fasteners such as screws. In addition, in laser welding, even small parts can be welded by appropriately changing the beam diameter of the laser light. On the other hand, there are problems with adhesives, such as the fact that they are often liquid and need to be stored in a refrigerator, that a coating process is required, that it takes time to harden, or that when heat is applied to harden them, heat is applied to material parts other than the adhesive, causing damage to the product. In addition, there are problems with using fasteners such as screws, such as making it difficult to miniaturize the product or increasing costs. As such, there is a growing need to use laser welding to join materials from various perspectives, such as improving productivity, being environmentally friendly, and reducing costs.

[0024] In recent years, there has been an increasing need to flexibly select materials to be welded according to the purpose of increasing waterproofness, dustproofness, heat resistance, durability, etc., or the application to be used. For example, there are cases where it is desired to join materials by utilizing the respective characteristics, such as a resin material with high insulation and glass with high visible light transmittance. There is an increasing need for such welded bodies of different materials in the fields of automobile parts and medical equipment, such as covers for in-vehicle sensors, covers for electronic control units, display panels, camera parts for endoscopes, and channels for microfluidic devices. However, there is a problem that it is difficult to join different materials, such as resin materials and inorganic glass, with high strength, because their physical properties, such as melting points or molecular structures, are different. In light of this situation, a method for laser welding different materials has been sought, and now, since it has been possible to weld different materials with high strength, the laser welding method for different materials according to the present embodiment will be described below.

[0025] Next, a method for laser welding dissimilar materials according to the present embodiment will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a diagram showing a welded body of dissimilar materials according to the present embodiment. Fig. 4 is a B-B cross-sectional view of the welded body according to the present embodiment.

[0026] The welded body 2 is a welded body in which the transparent material 20 is placed on the absorbing material 21, and the laser light LA ​​(see FIG. 4) is irradiated from the transparent material 20 to weld the region K. The axis parallel to the longitudinal direction of the facing surface 20A, which is the surface facing the surface that abuts against the absorbing material 21, in the outer peripheral surface of the transparent material 20 is defined as the Y axis. The axis perpendicular to the Y axis and parallel to the short side direction of the facing surface 20A is defined as the X axis. The axis perpendicular to both the X axis and the Y axis is defined as the Z axis. The expressions related to these directions are used for convenience of explanation and are not intended to limit the posture of the structure when actually used. The same applies to other drawings. The absorbing material 21 may be read as the first member. The transparent material 20 may be read as the second member.

[0027] The transparent material 20 is a thermoplastic resin material. In this embodiment, the transparent material 20 is preferably an ethylene-vinyl alcohol copolymer. Hereinafter, the ethylene-vinyl alcohol copolymer is referred to as EVOH. The transparent material 20 is preferably, but not limited to, EVOH. EVOH is a resin material obtained by hydrolysis of an ethylene-vinyl acetate copolymer. EVOH has high gas barrier properties and oil resistance. In addition, EVOH has properties such as high mechanical strength, high hardness, and antistatic properties. EVOH has a transmittance of 55% for light with a wavelength of 1070 nm at a thickness of 3 mm. The transmittance was measured using a spectrophotometer.

[0028] The absorbing material 21 is an inorganic material. For example, inorganic materials such as metal, ceramic, glass, and composites thereof can be selected for the absorbing material 21. In the present embodiment, when EVOH is selected for the transmitting material 20, the absorbing material 21 is preferably glass having a lower transmittance of the wavelength of laser light than EVOH. The glass contains an additive that absorbs laser light, that is, that reduces the transmittance of laser light. The glass is glass that absorbs laser light (that is, has high laser light absorption). The glass is, for example, infrared (IR) cut glass. The glass has a transmittance of 19% for light with a wavelength of 1070 nm at a thickness of 3 mm. Note that the transmittance of the absorbing material 21 is not limited to 19% of the glass, and is preferably lower than that of the transmitting material 20. For example, when EVOH is used for the transmitting material 20, the absorbing material 21 preferably has a transmittance of 20% or more for light with a wavelength of 1070 nm.

[0029] In the example shown in Fig. 3, the transmissive material 20 and the absorbing material 21 are rectangular parallelepipeds with flat outer circumferential surfaces. For convenience of explanation, the transmissive material 20 and the absorbing material 21 are shown as rectangular parallelepipeds, but the shapes of the transmissive material 20 and the absorbing material 21 are not limited to rectangular parallelepipeds and may be any shape and size. In addition, the transmissive material 20 and the absorbing material 21 do not need to have the same shape and may have different shapes.

[0030] A first surface 22, which is one surface of the outer circumferential surface of the transmitting material 20, and a second surface 23, which is one surface of the outer circumferential surface of the absorbing material 21, are arranged in contact with each other. Note that, although the first surface 22 and the second surface 23 are shown as flat surfaces in the example shown in Fig. 2, they may not be flat surfaces and may be curved surfaces, as long as at least the surfaces to be irradiated with the laser light LA ​​are in contact with each other.

[0031] The laser light LA ​​is incident from the transparent material 20 and irradiated to the absorbing material 21. For example, the laser light LA ​​is irradiated with an optical axis perpendicular to the opposing surface 20A of the transparent material 20. The optical axis of the laser light LA ​​is not limited to a direction perpendicular to the opposing surface 20A, and may be oblique to the opposing surface 20A. The laser light LA ​​is irradiated by being focused by a lens or the like (not shown) so that the focal position is located at the interface between the transparent material 20 and the absorbing material 21. The focal position of the laser light LA ​​may be a position shifted from the interface between the transparent material 20 and the absorbing material 21, and may be set to a position shifted to the transparent material 20 side or the absorbing material 21 side, for example. In addition, the laser light LA ​​may be a parallel light instead of a focused light as long as it can provide the absorbing material 21 with the thermal energy required for welding.

[0032] The absorbing material 21 absorbs the laser light LA. The laser light LA ​​absorbed by the absorbing material 21 is converted into heat, and the region 25 whose temperature exceeds the melting point due to the heat melts. The heat converted from the laser light LA ​​in the transmitting material 20 is conducted to the transmitting material 20, and the region 24 of the transmitting material 20 melts. When the laser light LA ​​is no longer irradiated, the regions 24 and 25 cool and solidify, and the transmitting material 20 and the absorbing material 21 are fused together in the region K. The length of the region K in the X-axis direction is approximately 10 cm. Note that the length of the region K is not limited to 10 cm. The wavelength of the laser light LA ​​is 800 nm to 1200 nm.

[0033] Generally, glass has a higher melting point than resin materials. Therefore, if glass is selected as the transmitting material and a thermoplastic resin material is selected as the absorbing material, the absorbing material may melt with a small amount of heat, and the heat conducted from the absorbing material may not melt the transmitting material sufficiently. For this reason, there is a risk that sufficient strength may not be obtained when glass and a thermoplastic resin material are laser welded together. In addition, in order to melt glass as a transmitting material, it is necessary to increase the power of the laser light or to extend the time for which the laser light is irradiated (i.e., the time for which the laser light is moved), which may result in a large-scale device or a decrease in productivity.

[0034] In the welding method according to the present embodiment, EVOH, which is a thermoplastic resin material, is selected as the transmitting material, glass, which has a lower transmittance of the wavelength of the laser light than the transmitting material, is selected as the absorbing material, and the laser light is irradiated from the transmitting material to the absorbing material. Since glass has a higher melting point than the thermoplastic resin material and can fully absorb the laser light before melting, EVOH, which is a thermoplastic resin material, is also fully melted by the heat conducted from the glass. In other words, both the transmitting material and the absorbing material on the surface irradiated with the laser light (in this embodiment, region K in FIG. 3) melt. When the laser light is no longer irradiated on the irradiated surface, the transmitting material and the absorbing material on the irradiated surface cool, and the transmitting material and the absorbing material are bonded and solidified. As a result, the welding method according to the present embodiment can use a laser to highly efficiently weld the different materials, glass and EVOH, which is a thermoplastic resin material. In addition, since both glass and EVOH, which is a thermoplastic resin material, melt sufficiently, they can be welded with high strength.

[0035] Next, an example of welding a plurality of transmissive materials to an absorptive material will be described with reference to Fig. 5. Fig. 5 is a diagram for explaining an example of welding a plurality of transmissive materials to an absorptive material.

[0036] 5 shows a cross section of a welded body 3 in which an absorbent material 21 is disposed on a permeable material 20C, and a permeable material 20B is further disposed on the absorbent material 21. The absorbent material 21 is sandwiched between the permeable material 20B and the permeable material 20C. The permeable materials 20B, 20C and absorbent material 21 shown in FIG. 5 are similar to the materials described in FIG. 3 and FIG.

[0037] The laser light LA ​​is irradiated from the transmissive material 20B to the absorbing material 21, the regions 26 and 27 melt, and the transmissive material 20B and the absorbing material 21 are welded to each other in the region K1.

[0038] The laser light LA ​​is irradiated from the transmissive material 20C to the absorbing material 21, the regions 28 and 29 melt, and the transmissive material 20C and the absorbing material 21 are welded to each other in the region K2.

[0039] In this way, the welding method according to the present embodiment can weld a plurality of transparent materials (e.g., EVOH) to an absorbent material (e.g., glass). When joining a plurality of transparent materials to an absorbent material using adhesive or fasteners such as screws, the number of steps of applying adhesive to the joining points and processing to attach the fasteners increases, which may reduce productivity. By welding different materials using the welding method according to the present embodiment, the plurality of transparent materials can be easily welded to the absorbent material, thereby improving productivity. Furthermore, by welding a plurality of transparent materials to an absorbent material using the welding method according to the present embodiment, even complex shapes can be flexibly welded, making it possible to perform fine processing and select the shape of a flexible material. EXAMPLES

[0040] Next, examples of the present disclosure will be described. Note that the present disclosure is not limited to these examples. Example 1 shown below is an example, and Example 2 is a comparative example.

[0041] (Example 1) The transmitting material and the absorbing material were arranged in the same manner as the transmitting material 20 and the absorbing material 21 shown in FIG. 3 and FIG. 4. The transmitting material and the absorbing material were in the shape of a rectangular parallelepiped flat plate, similar to the example shown in FIG. 3 and FIG. 4. The transmitting material was 3 mm EVOH. The absorbing material was glass, which has a lower transmittance than the 3 mm EVOH. The transmitting material had a transmittance of 55% for light with a wavelength of 1070 nm at a thickness of 3 mm. The absorbing material had a transmittance of 10% for light with a wavelength of 1070 nm at a thickness of 3 mm. The EVOH was irradiated with a laser beam and welded to the glass. The laser beam was irradiated so that the optical axis was perpendicular to the transmitting material, similar to the direction shown in FIG. 4. The laser was VL-W1A00 manufactured by Panasonic Industry Co., Ltd. The wavelength of the laser beam was 1070 nm, the beam diameter was 2 mm, the output was 70 W, and the speed was 10 mm / sec. The EVOH and the glass were irradiated with the laser beam once. The above-mentioned beam diameter refers to the beam diameter at the focal length of the laser light, and the focal position of the laser light is set at the interface between the transmitting material and the absorbing material. In this manner, a welded body of Example 1 was obtained.

[0042] (Example 2) The transparent material and the absorbing material were arranged in the same manner as the transparent material 20 and the absorbing material 21 shown in FIG. 3 and FIG. 4. The transparent material and the absorbing material were in the shape of a rectangular parallelepiped flat plate, similar to the example shown in FIG. 3 and FIG. 4. The transparent material was polyethylene terephthalate. The absorbing material was glass, which has a lower transmittance than polyethylene terephthalate. Laser light was incident from the polyethylene terephthalate and irradiated onto the glass to weld it. The laser used was a VL-W1A00 from Panasonic Industry. The wavelength of the laser light was 1070 nm, the beam diameter was 2 mm, the output was 70 W, and the moving speed was 10 mm / sec. The EVOH and the glass were irradiated with the laser light once. The above-mentioned beam diameter represents the beam diameter at the focal distance of the laser light. The focal position of the laser light is set at the interface between the transparent material and the absorbing material. In this manner, a welded body of Example 2 was obtained.

[0043] The bond strength of the welded body of Example 1 and the welded body of Example 2 are compared below. The bond strength was measured with a tensile tester. The bond strength of the welded body of Example 1 is 14.8 MPa. The bond strength of the welded body of Example 2 is 1 MPa. In other words, the bond strength of the welded body of Example 1 is significantly higher than that of the welded body of Example 2, and is firmly bonded. The EVOH and glass of Example 1 can be firmly bonded using a laser welding method.

[0044] The bonding strength of the welded body made by bonding the transmitting material and the absorbing material is equal to or greater than the breaking strength of the transmitting material when the welded body is used at room temperature. In other words, when the transmitting material is a resin material, the bonding strength of the welded body is equal to or greater than the breaking strength of the resin material. The breaking strength of the resin material is, specifically, the breaking strength of the resin material when used at room temperature in a test according to the ASTM standard test method, which is approximately 10 MPa or more.

[0045] As a result, the EVOH and glass of Example 1 could be firmly laser welded without using adhesives or fasteners such as screws. In addition, the moving speed of the laser light was 10 mm / sec, so for example, when moving 10 cm, welding could be completed in 10 seconds. In addition, since the beam diameter was 2 mm, it was possible to weld small parts with a welding area of ​​the order of millimeters. As a result, the welded body of Example 1 was firmly welded in a short time, and high productivity, high quality, and fine processing were all achieved.

[0046] (Summary of this embodiment) The above description of the present embodiment discloses the following techniques.

[0047] <Technology 1> The welding method according to the present embodiment is a method for welding a first member and a second member using a laser beam, the first member including an inorganic material, and the second member including an ethylene-vinyl alcohol copolymer resin. In the welding method, the transmittance of the first member at the wavelength of the laser beam is lower than the transmittance of the second member at the wavelength of the laser beam, and the laser beam is irradiated to the contact portion between the first member and the second member so as to pass through the second member, thereby welding the first member and the second member.

[0048] As a result, the welding method according to the present embodiment can laser weld the inorganic material and EVOH, which are dissimilar materials. As a result, the welding method according to the present embodiment can weld the dissimilar materials without using adhesives or fasteners such as screws. Since the adhesive may contain harmful substances, the welding method can reduce the adverse effects on the environment. Furthermore, since the handling and additional processing of adhesives or fasteners such as screws can be omitted, the welding method can improve productivity.

[0049] <Technology 2> In the fusing method described in Technique 1, the first member is glass.

[0050] As a result, the welding method according to the present embodiment can laser weld the glass and the EVOH.

[0051] <Technology 3> In the fusing method according to the first or second technique, the first member is glass containing an additive that reduces the transmittance of the wavelength of the laser beam.

[0052] As a result, in the welding method according to the present embodiment, the glass absorbs the laser light sufficiently, and melts well, enabling strong welding to the EVOH.

[0053] <Technology 4> In the welding method according to any one of Techniques 1 to 3, the transmittance of the first member at the wavelength of the laser light is less than 55% when the first member has a thickness of 3 mm.

[0054] Thereby, the welding method according to the present embodiment can laser weld the first member and the second member by using a first member having a lower transmittance than the second member.

[0055] <Technology 5> In the welding method according to any one of Techniques 1 to 4, the wavelength of the laser light is 800 nm to 1200 nm.

[0056] As a result, the welding method according to the present embodiment can weld dissimilar materials together using a laser beam with a wavelength of 800 nm to 1200 nm.

[0057] Although the embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications, corrections, substitutions, additions, deletions, and equivalents within the scope of the claims, and it is understood that these also belong to the technical scope of the present disclosure. In addition, the components in the above-mentioned embodiments may be arbitrarily combined within the scope of the invention. [Industrial Applicability]

[0058] The technology disclosed herein is useful as a welding method and a welded body for laser welding dissimilar materials. [Explanation of symbols]

[0059] 1,2,3 Welding body 10,20,20B,20C transparent material 11,21 Absorbent materials 12,20A Opposite surface 22 Page 1 23 Side 2 P1,P2,K,K1,K2,24,25,26,27,28,29 area LA Laser Light

Claims

1. A method for welding a first member and a second member using laser light, The first member includes an inorganic material, the second member includes an ethylene-vinyl alcohol copolymer resin, the transmittance of the first member at a wavelength of the laser light is lower than the transmittance of the second member at a wavelength of the laser light, the laser light is irradiated to a contact portion between the first member and the second member so as to pass through the second member, thereby welding the first member and the second member. Welding method.

2. The first member is glass. The welding method according to claim 1.

3. The first member is glass containing an additive that reduces the transmittance of the wavelength of the laser light. The welding method according to claim 2.

4. The transmittance of the first member at the wavelength of the laser light is less than 55% when the first member has a thickness of 3 mm. The welding method according to claim 1.

5. The wavelength of the laser light is 800 nm to 1200 nm. The welding method according to claim 1.

6. A welded body is obtained by a method of welding a first member made of an inorganic material and a second member made of an ethylene-vinyl alcohol copolymer resin using a laser beam, the transmittance of the first member at a wavelength of the laser light is lower than the transmittance of the second member at a wavelength of the laser light, The laser light is irradiated to a contact portion between the first member and the second member so as to pass through the second member, thereby welding the first member and the second member. Welded body.

7. The bonding strength between the first member and the second member is equal to or greater than the breaking strength of a resin member. The welded body according to claim 6.

Images