Seal structure between dissimilar materials and method for manufacturing seal structure between dissimilar materials

Abstract

This seal structure between dissimilar materials includes: a busbar (columnar base material) with a roughened region provided on a surface thereof; a film adhesive wrapped around the outer periphery of the busbar; and a resin bonded at least from the roughened region of the busbar to the portion where film adhesive is wrapped.

Description

Seal structure between different materials and method for manufacturing the seal structure between different materials

[0001] The present disclosure relates to a seal structure between dissimilar materials and a method for manufacturing the seal structure between dissimilar materials.

[0002] Japanese Patent No. 7485170 discloses an electric / electronic component in which an adhesive thermoplastic film is wrapped around at least a portion of the outer periphery of a columnar substrate and a resin is bonded to the portion of the columnar substrate where the thermoplastic film is wrapped. Japanese Patent No. 7485227 also discloses a technique in which a resin is bonded to the portion of the columnar substrate where the thermoplastic film is wrapped by insert molding to seal the thermoplastic film.

[0003] However, in a structure in which different materials are simply joined using an adhesive thermoplastic film, there is a concern that the sealing ability of the thermoplastic film will decrease under conditions in which thermal expansion and contraction are repeated.

[0004] The present disclosure aims to improve the sealing properties of a structure in which different materials are joined.

[0005] The sealing structure between dissimilar materials according to the first aspect comprises a columnar substrate having a roughened region on its surface, a film adhesive wrapped around the outer periphery of the columnar substrate, and a resin bonded to the columnar substrate from at least the roughened region to the wrapped portion of the film adhesive.

[0006] In this sealing structure between dissimilar materials, the resin bonds with the roughened region of the columnar substrate, resulting in a stronger bond between the resin and the columnar substrate than when the roughened region is not provided. Therefore, even if the resin expands or contracts due to heat, the stress acting on the film adhesive is suppressed, and the adhesion between the columnar substrate and the film adhesive is maintained.

[0007] In a second aspect, in the seal structure between different materials according to the first aspect, the roughened regions are provided on both sides of the wound portion of the film adhesive in the axial direction of the columnar substrate.

[0008] In this sealing structure between different materials, the adhesive strength between the resin and the columnar substrate is increased on both sides of the wound portion of the film adhesive, thereby maintaining the adhesiveness between the columnar substrate and the film adhesive.

[0009] In a third aspect, in the sealing structure between different materials according to the first or second aspect, a plurality of wound portions of the film adhesive are provided in the axial direction of the columnar substrate, and the roughened region is provided between adjacent wound portions of the film adhesive.

[0010] In this sealing structure between different materials, the adhesive strength between the resin and the columnar substrate is increased between the adjacent wound portions of the film adhesive, thereby maintaining the adhesiveness between the columnar substrate and the film adhesive.

[0011] In a fourth aspect, in a sealing structure between different materials according to any one of the first to third aspects, at least a portion of the roughened area overlaps with the wrapped portion of the film adhesive, and the convex portion of the roughened area penetrates the film adhesive and is bonded to the resin.

[0012] In this sealing structure between dissimilar materials, at least a portion of the roughened area overlaps with the wrapped portion of the film adhesive, thereby increasing the bonding strength between the resin and the columnar substrate, thereby maintaining the adhesion between the columnar substrate and the film adhesive.

[0013] A manufacturing method for a sealing structure between different materials according to a fifth aspect includes preparing a columnar substrate having a roughened region or a region to be roughened on its surface, wrapping a film adhesive around a predetermined position on or near the roughened region, or around a predetermined position near the region to be roughened, providing a roughened region in the region to be roughened if the region to be roughened is provided, and bonding a resin from the roughened region to the columnar substrate over at least the portion where the film adhesive is wrapped.

[0014] According to the present disclosure, it is possible to improve the sealing performance of a structure in which different materials are joined.

[0015] 9 is a front view showing a columnar substrate having a roughened region in the first embodiment. (A) is a front view showing a state in which a film adhesive is wrapped around a columnar substrate. (B) is a cross-sectional view taken along the arrows 2B-2B in (A). (A) is a cross-sectional view showing a sealing structure between different materials according to the first embodiment. (B) is a cross-sectional view taken along the arrows 3B-3B in (A). (C) is a cross-sectional view taken along the arrows 3C-3C in (A). An enlarged cross-sectional view of part A in FIG. 3, showing the bonding state between the resin and the roughened region. A front view showing a sealing structure between different materials according to a modified example. A front view showing a sealing structure between different materials according to a second embodiment. A front view showing a sealing structure between different materials according to a third embodiment. An enlarged cross-sectional view taken along the arrows 8-8 in FIG. 7. A front view showing a sealing structure between different materials according to a fourth embodiment. An enlarged cross-sectional view taken along the arrows 10-10 in FIG. 9.

[0016] Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. Components indicated by the same reference numerals in each drawing are the same or similar components. Note that duplicated explanations and reference numerals may be omitted in the embodiments described below. Furthermore, all drawings used in the following description are schematic, and the dimensional relationships, ratios, etc. of each element shown in the drawings do not necessarily match those in reality. Furthermore, the dimensional relationships, ratios, etc. of each element between multiple drawings do not necessarily match.

[0017] In this specification, "bonding" means joining two objects together, with adhesion and welding being subordinate concepts. "Bonding" means joining two adherends (objects to be bonded) together using an organic material such as tape or adhesive (such as a thermosetting resin or a thermoplastic resin). "Welding" means melting the surface of a thermoplastic resin or the like with heat, and then cooling it to cause entanglement through molecular diffusion, resulting in a joined state. "Adhesion" means the property of having adhesive strength sufficient to join two objects together.

[0018] 3 , a sealing structure S1 between dissimilar materials according to this embodiment is used, for example, as the structure of a terminal block 20. The sealing structure S1 between dissimilar materials includes a bus bar 12 as an example of a columnar substrate, a film adhesive 14, and a resin 16.

[0019] 1 and 2 , the bus bar 12 is formed in a plate shape using, for example, a conductive material, and has a roughened region 18 on its surface. The roughened region 18 is provided on the outer side of both sides of the portion of the bus bar 12 where the film adhesive 14 is wrapped in the axial direction. Techniques such as laser or etching can be used to form the roughened region 18. For example, the techniques described in Japanese Patent No. 7184178 and Japanese Patent No. 6103010 can be used.

[0020] 2 and 3, the film adhesive 14 is, for example, rectangular and is wrapped around the outer periphery of a portion of the bus bar 12. This film adhesive 14 is a thin synthetic resin film made of a thermoplastic resin and is used to join different materials.

[0021] As shown in Fig. 2(B), both ends 14A, 14B of the film adhesive 14 may overlap each other. As shown in Fig. 3(C), both ends 14A, 14B of the film adhesive 14 may not overlap each other. Also, as in a fourth embodiment (Fig. 9) described later, the ends 14A, 14B of the film adhesive 14 may not overlap each other but may be spaced apart. As shown in Fig. 5, the ends 14A, 14B of the film adhesive 14 may be spaced apart by a distance within the range covered by the resin 16.

[0022] The resin 16 is an insulator that is bonded to the bus bar 12 from at least the roughened region 18 to the portion where the film adhesive 14 is wrapped. This resin 16 is bonded by, for example, insert molding, covering the area from the roughened region 18 of the bus bar 12 to the film adhesive 14 wrapped around the bus bar 12. In other words, the roughened region 18 and the film adhesive 14 are embedded within the resin 16. This seals the space between the bus bar 12 and the resin 16, ensuring watertightness and airtightness. Furthermore, as shown in FIG. 4 , the roughened region 18 and the resin 16 are firmly bonded to each other in an intertwined state.

[0023] 5, the width of the film adhesive 14 in the axial direction of the bus bar 12 may be set to be relatively short. The width of the film adhesive 14 can be changed as desired.

[0024] The film adhesive 14 contains a thermoplastic resin as a main component. Preferably, the film adhesive 14 has adhesiveness to the bus bar 12. The "main component" refers to the component with the highest content among the resin components in the thermoplastic film B. The film adhesive 14 preferably contains 50% by mass or more of the resin component, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more. The "film" refers to a resin composition containing a thermoplastic resin as a main component, molded into a thin film.

[0025] <<Y°C - X°C>> If the thermoplastic resin used in the film adhesive 14 has a melting point, the melting point of the film adhesive 14 is X°C. Alternatively, if the thermoplastic resin used in the film adhesive 14 does not have a melting point, X°C is the temperature obtained by adding 70°C to the glass transition temperature. Let Y°C be the resin temperature during molding of the resin 16. The value obtained by subtracting X°C from Y°C (Y°C - X°C) is preferably 0 to 300°C, more preferably 50 to 250°C, even more preferably 100 to 250°C, and even more preferably 125 to 210°C. When the Y°C - X°C value is in the range of 0 to 300°C, the film adhesive 14 efficiently melts due to the heat generated by the resin 16 during molding, effectively spreading across the bonding surface, resulting in high adhesion and excellent leak resistance. In this specification, the melting point of a thermoplastic resin refers to the peak melting temperature measured by DSC. If no melting peak is obtained or if the heat of fusion is 15 J / g or less, the melting point is considered to be the glass transition temperature plus 70°C. The glass transition temperature refers to the temperature at which the DSC curve starts to drop in the second cycle after heating to 200°C by DSC, cooling to 40°C or less, and further heating to 200°C.

[0026] Such a thermoplastic resin is preferably one containing an amorphous thermoplastic resin as a main component, and from the viewpoint of hermetic sealing property and toughness, the amorphous thermoplastic resin is preferably at least one selected from the group consisting of a thermoplastic epoxy resin and a phenoxy resin. Here, the thermoplastic epoxy resin may be a polymer of (a) a bifunctional epoxy resin monomer or oligomer and (b) a bifunctional compound having two identical or different functional groups selected from the group consisting of a phenolic hydroxyl group, a carboxyl group, a mercapto group, an isocyanate group, and a cyanate ester group (excluding polyhydroxypolyethers synthesized from bisphenols and epichlorohydrin), and the phenoxy resin is a polyhydroxypolyether synthesized from bisphenols and epichlorohydrin.

[0027] Specifically, the film adhesive 14 may be, for example, the thermoplastic film disclosed in Japanese Patent Nos. 7485170 and 7485227, or WelQuick (registered trademark) manufactured by Resonac Co., Ltd. In this embodiment, the thickness of the film adhesive 14 is, for example, 0.05 mm. The thickness of the film adhesive 14 shown in each drawing is exaggerated to make the state of the film adhesive 14 easier to understand.

[0028] The resin 16 is not particularly limited as long as it is a resin different from the resin portion in the film adhesive 14, but is preferably one that can be insert molded, and examples thereof include polyethylene-based resins, polypropylene-based resins (PP), composite polypropylene-based resins (PPC), polyphenylene sulfide-based resins (PPS), polyphthalamide-based resins (PPA), polybutylene terephthalate-based resins (PBT), epoxy-based resins, phenol-based resins, polystyrene-based resins, polyethylene terephthalate-based resins, polyvinyl alcohol-based resins, vinyl chloride-based resins, ionomer-based resins, polyamide-based resins, acrylonitrile-butadiene-styrene copolymer resins (ABS), and polycarbonate-based resins.

[0029] The resin 16 may contain an inorganic filler such as glass, silica, alumina, zircon, magnesium oxide, calcium silicate, calcium carbonate, potassium titanate, silicon carbide, silicon nitride, boron nitride, beryllia, zirconia, etc. Aluminum hydroxide, zinc borate, etc. may also be used as a flame-retardant inorganic filler.

[0030] The molding temperature (resin temperature) of the resin 16 is preferably 100° C. to 400° C., more preferably 150° C. to 350° C., and even more preferably 180° C. to 300° C. By performing injection molding within the range of 100° C. to 400° C., the film adhesive 14 is efficiently deformed and melted by heating, and effectively wets and spreads over the bonding surface, resulting in high bonding strength.

[0031] The busbar 12 may be made of a metal or an inorganic material, and one type may be used alone or two or more types may be used in combination. From the viewpoints of heat resistance and strength, the busbar 12 is preferably made of a metal. If the busbar 12 is made of a resin, the resin material must have a melting point or glass transition temperature that does not deform at the temperature used in insert molding. The metal is not particularly limited, and examples include aluminum, iron, copper, magnesium, and titanium. In this embodiment, the term "iron" is used to include iron and its alloys. Examples of iron alloys include steel and stainless steel. Similarly, the terms copper, aluminum, magnesium, and titanium are used to include these elements and their alloys.

[0032] The inorganic material is not particularly limited, and examples thereof include glass, ceramic, and carbon molded body.

[0033] (Operation) This embodiment is configured as described above, and its operation will be described below. In the seal structure S1 between dissimilar materials according to this embodiment, as shown in FIG. 3 , the resin 16 is bonded to the roughened region 18 of the bus bar 12. This provides a higher bond strength between the resin 16 and the bus bar 12 than when the roughened region 18 is not provided (see also FIG. 4 ). Therefore, even if the resin 16 expands or contracts due to heat, stress acting on the film adhesive 14 is suppressed, and peeling of the film adhesive 14 from the bus bar 12 is suppressed. This maintains the adhesion between the bus bar 12 and the film adhesive 14.

[0034] In addition, by increasing the bonding strength between the resin 16 and the bus bar 12 on both sides of the wrapped portion of the film adhesive 14, the stress acting on the film adhesive 14 can be further suppressed, and the adhesion between the bus bar 12 and the film adhesive 14 can be maintained.

[0035] As described above, according to this embodiment, it is possible to improve the sealing performance of a structure in which different materials are joined together, such as the embedded portion of the bus bar 12 in the terminal block 20 .

[0036] 6 , in a seal structure S2 between dissimilar materials according to this embodiment, a plurality of wound portions of the film adhesive 14 are provided in the axial direction of the bus bar 12. A roughened region 18 is provided between adjacent wound portions of the film adhesive 14.

[0037] In this embodiment, the adhesive strength between the resin 16 and the bus bar 12 is increased between the adjacent wound portions of the film adhesive 14, so that the adhesiveness between the bus bar 12 and the film adhesive 14 can be maintained.

[0038] 7 and 8 , in a seal structure S3 between dissimilar materials according to this embodiment, at least a portion of roughened region 18 overlaps with the wrapped portion of film adhesive 14. In areas where the thickness of film adhesive 14 is smaller than the height of the convex portions of roughened region 18, the convex portions of roughened region 18 may penetrate film adhesive 14. In areas where the convex portions of roughened region 18 penetrate film adhesive 14, roughened region 18 and resin 16 are bonded together.

[0039] In this embodiment, even if the roughened region 18 and the film adhesive 14 overlap, the roughened region 18 and the resin 16 can be bonded together. By overlapping at least a portion of the roughened region 18 with the wrapped portion of the film adhesive 14, the bonding strength between the resin 16 and the bus bar 12 can be increased, and the adhesion between the bus bar 12 and the film adhesive 14 can be maintained.

[0040] 9 and 10 , in a seal structure S4 between dissimilar materials according to this embodiment, both ends 14A, 14B of the film adhesive 14 are spaced apart and do not overlap each other. Furthermore, the roughened region 18 is provided between both ends 14A, 14B of the film adhesive 14 and in the range overlapping with the ends 14A, 14B. In other words, a portion of the roughened region 18 overlaps with the ends 14A, 14B. The roughened region 18 is bonded to the resin 16 between both ends 14A, 14B of the film adhesive 14, and in the region overlapping with the ends 14A, 14B, the roughened region 18 penetrates the film adhesive 14 and is bonded to the resin 16 through the film adhesive 14, as in the third embodiment.

[0041] In this embodiment, the roughened region 18 is bonded to the resin 16, and at least a portion of the roughened region 18 is overlapped with the wrapped portion of the film adhesive 14 to increase the bonding strength between the resin 16 and the bus bar 12, thereby maintaining the adhesion between the bus bar 12 and the film adhesive 14.

[0042] (Method for manufacturing a seal structure between dissimilar materials) The method for manufacturing a seal structure between dissimilar materials according to this embodiment includes preparing a bus bar 12 (columnar substrate) having a roughened region 18 or a region to be roughened on its surface, wrapping a film adhesive 14 around a predetermined position on or near the roughened region 18, or around a predetermined position near the region to be roughened, providing a roughened region 18 in the region to be roughened if a region to be roughened is provided, and joining a resin 16 to at least the area from the roughened region 18 to the portion of the bus bar 12 around which the film adhesive 14 is wrapped.

[0043] In the first and second embodiments, the roughened region 18 may be provided after the film adhesive 14 is wound. That is, the roughened region 18 may be a region to be roughened before the film adhesive 14 is wound. The region to be roughened becomes the roughened region 18 by roughening it. In the third and fourth embodiments, the roughened region 18 is provided in advance before the film adhesive 14 is wound.

[0044] According to the present disclosure, an improved sealing structure between dissimilar materials can be provided.

[0045] [Other Embodiments] Although one example of an embodiment of the present disclosure has been described above, the embodiment of the present disclosure is not limited to the above, and it goes without saying that various modifications can be made without departing from the spirit of the present disclosure.

[0046] Although the bus bar 12 has been given as an example of the columnar substrate, the columnar substrate is not limited to the bus bar 12 and can be suitably used for any application that requires sealing properties. Examples of such applications include terminal blocks for automobiles, terminal blocks for electric and electronic components, and electric elements.

[0047] The disclosure of Japanese Patent Application No. 2024-128087, filed on August 2, 2024, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards mentioned herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A sealing structure between dissimilar materials comprising: a columnar substrate having a roughened region on its surface; a film adhesive wrapped around the outer periphery of the columnar substrate; and a resin bonded to the columnar substrate from at least the roughened region over the area where the film adhesive is wrapped.

2. The sealing structure between dissimilar materials according to claim 1, wherein the roughened areas are provided on both sides of the wound portion of the film adhesive in the axial direction of the columnar substrate.

3. A sealing structure between dissimilar materials as described in claim 1, wherein a plurality of wound portions of the film adhesive are provided in the axial direction of the columnar substrate, and the roughened region is provided between adjacent wound portions of the film adhesive.

4. A sealing structure between dissimilar materials as described in claim 1, wherein at least a portion of the roughened area overlaps with the wrapped portion of the film adhesive, and the convex portion of the roughened area penetrates the film adhesive and is bonded to the resin.

5. A method for manufacturing a sealing structure between dissimilar materials, comprising: preparing a columnar substrate having a roughened region or a region to be roughened on its surface; wrapping a film adhesive around a predetermined position on or near the roughened region, or a predetermined position near the region to be roughened; if the region to be roughened is provided, providing a roughened region in the region to be roughened; and bonding a resin from the roughened region of the columnar substrate to at least the portion where the film adhesive is wrapped.

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