Method for producing joined body, joined body, and electrical / electronic component

Abstract

Disclosed is a method for producing a joined body by sequentially joining a columnar base material A, a thermoplastic film B, and a resin C in this order, the method including: heating and melting, and solidifying the thermoplastic film B that is disposed on at least a part of the outer periphery of the columnar base material A so as to join the columnar base material A and the thermoplastic film B; and joining a portion of the columnar base material A, on which the thermoplastic film B is disposed, and the resin C by means of insert molding so as to seal the thermoplastic film B. The heating and melting are performed by bringing the thermoplastic film B into contact with the columnar base material A which has been heated in advance.

Description

Method for manufacturing joined body, joined body, and electric / electronic component

[0001] The present invention relates to a method for manufacturing a bonded body in which different materials are firmly bonded, a bonded body, and an electric / electronic component.

[0002] In recent years, from the perspective of reducing product weight and improving performance, the use of multi-material components has been progressing in various fields, including automobile parts, medical equipment, and home appliances. Multi-materialization is a method of reducing the weight and increasing the strength of materials by combining materials with different functions and properties (hereinafter referred to as dissimilar materials). To achieve multi-materialization, technology to firmly join dissimilar materials is essential.

[0003] Capacitors are an example of a product that uses components that require multi-materialization. Capacitors are configured with at least an insulator and an electrode body inside an outer container. In many cases, the electrode body has a positive electrode and a negative electrode extending from through-holes in the outer container to exchange electricity with the outside. To protect the inside of the outer container from problems such as deterioration due to the atmosphere, a method is used in which a resin material is used as a sealant to seal the gap between the electrode body and the through-hole. Electronic devices, in particular, often experience problems due to even slight moisture or dust, so high levels of adhesion (leak resistance) are required in the sealed parts.

[0004] For example, a technique for sealing the periphery of a metal terminal by insert molding, such as injection molding, using a resin material as a sealant is known. However, when a resin material is sealed around a metal by insert molding, there is a risk of leakage through gaps. In particular, when a resin material is sealed around a metal terminal, etc., superior leak resistance is required. Therefore, as a means for sealing a metal terminal, etc., with a resin material, for example, a method of applying a liquid adhesive or varnish to the metal terminal and then sealing with a resin material by insert molding has been investigated. Specifically, a technique for forming a sealing portion is known, in which an in-situ polymerizing composition is applied to an electrode body and polymerized to form a primer layer (Patent Document 1, etc.). Another technique is known, in which an external terminal is immersed in a bath filled with a cationic epoxy resin-based electrodeposition paint, and current is applied to form a terminal adhesive layer, followed by forming a sealing member (Patent Document 2, etc.). Furthermore, a method for roughening the surface of a metal terminal and then sealing with a resin material by insert molding has also been investigated. Specifically, a technique is known in which the surface layer of the joint surface of the metal terminal with the sealing resin is polished by mechanical polishing such as sandblasting, shot blasting, grinding, barrel processing, etc., or by chemical polishing (Patent Document 3, etc.).

[0005] JP 2021-157887 A JP 2020-88137 A JP 2016-126989 A

[0006] However, liquid adhesive application techniques can require a long time for bonding, potentially resulting in issues such as reduced pot life (usable time) and labor. Furthermore, insufficient application or uneven application can reduce leak resistance. Liquid adhesive application techniques also pose a risk of contamination due to excessive application. Furthermore, when using liquid thermosetting adhesives, when metal terminals are repeatedly exposed to high and low temperatures (during thermal cycling), the difference in the linear expansion coefficients between the metal terminals and the encapsulating resin causes misalignment, placing stress on the adhesive layer. The adhesive layer is then unable to relieve stress and peels, leading to leaks. This is because the thermosetting adhesive layer lacks thermoplasticity and rapidly breaks when it reaches the plastic deformation range. While roughening the surface of the electrode assembly can increase adhesion to the encapsulating material, gaps are likely to form between the roughened surface of the electrode assembly and the encapsulating material, potentially resulting in insufficient leak resistance. Furthermore, the lack of a layer to relieve stress during thermal cycling makes the adhesive prone to peeling. To ensure even better sealing performance, not only is there a need for stronger adhesion between the substrate and the sealing material, but stress relaxation during thermal cycling is also required.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method for manufacturing a bonded body that can be bonded in a short time, can firmly bond different materials, and has excellent leak resistance, as well as a bonded body and an electric / electronic component.

[0008] The present inventors have found that the above-mentioned problems can be solved by sealing with a resin the area where a predetermined film is disposed on the outer periphery of a substrate.

[0009] [1] A method for producing a bonded body by bonding a columnar substrate A, a thermoplastic film B, and a resin C in this order, the method comprising: heating and melting and solidifying the thermoplastic film B arranged on at least a portion of the outer periphery of the columnar substrate A to bond the columnar substrate A and the thermoplastic film B; and bonding the portion of the columnar substrate A where the thermoplastic film B is arranged and the resin C by insert molding to seal the thermoplastic film B, the method comprising: bringing the thermoplastic film B into contact with the preheated columnar substrate A to melt the thermoplastic film B; [2] A method for producing a bonded body according to [1], wherein the heat and melting is performed at 100 to 200°C; [3] A method for producing a bonded body according to [1] or [2], wherein the thermoplastic film B has adhesiveness to the columnar substrate A; [4] A method for producing a bonded body according to any of [1] to [3], wherein the width of the thermoplastic film B in a direction perpendicular to the circumferential direction of the columnar substrate A is 3 to 30 mm. [5] The method for producing a joined body according to any one of [1] to [4], wherein the thickness of the thermoplastic film B is 10 μm or more and 3 mm or less. [6] The method for producing a joined body according to any one of [1] to [5], wherein the melting point of the thermoplastic film B, or the glass transition temperature plus 70°C if the melting point does not exist, is defined as X°C, and the resin temperature during molding of the resin C is defined as Y°C, and the value obtained by subtracting X°C from Y°C is 100 to 250°C. [7] The method for producing a joined body according to any one of [1] to [6], wherein the thermoplastic film B is mainly composed of an amorphous thermoplastic resin. [8] The method for producing a joined body according to [7], wherein the amorphous thermoplastic resin is a resin having a heat of fusion of 15 J / g or less. [9] The method for producing a joined body according to [7], wherein the amorphous thermoplastic resin is at least one of a thermoplastic epoxy resin and a phenoxy resin.

[10] The thermoplastic film B has an epoxy equivalent of 1,600 g / eq.

[11] The method for producing a bonded body according to any one of [1] to

[10] , wherein the columnar substrate A is a metal.

[12] The method for producing a joined body according to any one of [1] to

[11] , wherein the resin C is a thermoplastic resin.

[13] The method for producing a joined body according to any one of [1] to

[12] , wherein the thermoplastic film B is a film obtained by removing the solvent from a resin composition dissolved in a solvent.

[14] A joined body obtained by the method for producing a joined body according to any one of [1] to

[13] , wherein, when a leak test is conducted by applying an air pressure of 0.1 MPaG to the sealed portion, the amount of air leakage is 1 ml / min or less.

[15] The joined body according to

[14] , wherein, when the joined body is heated to 160°C, maintained at 160°C for 1,000 minutes, cooled to 23°C, and then the amount of air leakage is 1 ml / min or less.

[16] An electric / electronic component comprising at least one joined body selected from the group consisting of a joined body obtained by the method for producing a joined body according to any one of [1] to

[13] , the joined body according to

[14] , and the joined body according to

[15] .

[17] The electric / electronic component according to the above

[16] , which is a terminal block or an electric element.

[0010] According to the present invention, it is possible to provide a method for manufacturing a bonded body, a bonded body, and an electric / electronic component that require a short bonding process time, bond different materials firmly, and have excellent leak resistance.

[0011] FIG. 1 is a front view showing an example of an embodiment of a substrate with a film. FIG. 2 is an explanatory diagram of step 1, showing a cross section of the substrate with a film in FIG. 1 cut along the B-B' plane parallel to the Y axis. FIG. 3 is an explanatory diagram of step 2, showing a cross section of the substrate with a film and a mold obtained in step 1. FIG. 4 is a cross section of a cut surface parallel to the width direction of a bonded body. FIG. 5 is a cross section of a cut surface parallel to the length direction of a bonded body. FIG. 6 is a schematic diagram of a bonded body for explaining an example.

[0012] Embodiments of the present invention will be described in detail below. In this specification, "bonding" refers to joining two objects together, with adhesion and welding being subordinate concepts. "Bonding" refers to 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" refers to 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 bonded state. "Adhesion" refers to the property of having adhesive strength sufficient to join two objects together. In this specification, "a bonded body formed by bonding in this order" refers to the spatial bonding in this order. In this specification, "bonding process time" refers to the time from the start point when the substrate and film constituting the bonded body come into contact with each other to the end point when the fabrication of the bonded body is completed. For example, this includes the time required for the process of placing a film on the substrate and the time required for bonding and sealing the resin by insert molding. In this specification, the term "to" is used to express the upper and lower limits of a numerical range or physical quantity. The upper and lower limits of the numerical ranges can be combined in any way.

[0013] <Method for manufacturing a bonded body> The method for manufacturing a bonded body of this embodiment is a method for manufacturing a bonded body by bonding a columnar substrate A, a thermoplastic film B, and a resin C in this order, and includes heating, melting, and solidifying the thermoplastic film B arranged on the outer periphery of at least a portion of the columnar substrate A to bond the columnar substrate A and the thermoplastic film B, and joining the portion of the columnar substrate A where the thermoplastic film B is arranged and the resin C by insert molding to seal the thermoplastic film B. The heating and melting is carried out by contacting the thermoplastic film B with the preheated columnar substrate A. When the thermoplastic film B is contacted with the preheated columnar substrate A, at least a portion of the thermoplastic film B in contact with the columnar substrate A melts upon contact. Since the thermoplastic film B, at least a portion of which is melted on the columnar substrate A, is less likely to shift position, the thermoplastic film B can be adhered to the columnar substrate A in an accurate position. Furthermore, even when a thermoplastic film B without tackiness is used, temporary fixation after contact with the substrate is not required. In this specification, the outer periphery of the columnar substrate A means the entire circumference of the outside of the columnar substrate A. The thermoplastic film B may be arranged by wrapping a single thermoplastic film B around the outer periphery of the columnar substrate A, or a plurality of thermoplastic films B may be arranged side by side around the outer periphery of the columnar substrate A. "Wrapping" means wrapping the thermoplastic film B around the columnar substrate A in the circumferential direction once or more than once.

[0014] In one embodiment, the method includes the steps of wrapping the thermoplastic film B around the preheated columnar substrate A to heat-melt and solidify the thermoplastic film B, and insert-molding the resin C to bond the portion of the columnar substrate A around which the thermoplastic film B is wrapped, thereby sealing the thermoplastic film B. By providing the thermoplastic film B between the columnar substrate A and the sealing resin C, the columnar substrate A and the resin C are firmly bonded. Because the thermoplastic film B can be wrapped around the columnar substrate A, this is an effective operation for shortening the bonding process compared to applying a liquid adhesive or the like. Furthermore, using a thermoplastic film B with a uniform thickness eliminates uneven areas such as uncoated areas and drips compared to applying a liquid adhesive or the like, thereby achieving excellent leak resistance.

[0015] The detailed reasons why the effects of the present invention are achieved are considered as follows. By providing a thermoplastic resin in which a chemical reaction such as polymerization has been completed between the columnar substrate A and resin C, rapid curing is possible by utilizing the phase change between solid and liquid, thereby shortening the bonding process. Furthermore, using a thermoplastic resin in film form eliminates the complicated liquid handling process compared to applying an amorphous liquid bonding agent, shortening the bonding process time. Furthermore, a thermoplastic resin retains its thermoplasticity even at high temperatures, allowing stress to be relieved, and stress can be reset after each thermal cycle, preventing delamination. Therefore, using thermoplastic film B allows for plastic deformation and effective stress relief, resulting in a bonded structure that is less likely to delaminate during thermal cycles and has excellent leak resistance. Furthermore, resin C softens when the bonded structure is exposed to high temperatures, allowing for even more effective stress relief, resulting in excellent leak resistance. Furthermore, as an example of a preferred embodiment, when an amorphous thermoplastic film B is used as the thermoplastic film B, the film is unlikely to undergo a sudden decrease in viscosity when heated, and therefore the bonded body can maintain its shape to maintain leak resistance when exposed to high temperatures.

[0016] [Step 1] In step 1, a thermoplastic film B is wrapped around a preheated columnar substrate A, whereby the thermoplastic film B is heated, melted, and solidified to bond the columnar substrate A and the thermoplastic film B. An example of an embodiment of step 1 will be described with reference to FIGS. 1 and 2. FIG. 1 is a front view showing an example of an embodiment of a film-attached substrate. FIG. 2 is an explanatory diagram of step 1, showing a cross section of the film-attached substrate in FIG. 1, taken along the B-B' cut plane parallel to the Y axis. As shown in FIGS. 1 and 2, the thermoplastic film B30 may be disposed around at least a portion of the outer periphery of the columnar substrate A20. In this case, as shown in FIG. 1, the non-adhered portion a of the thermoplastic film B30 may be present in part of the columnar substrate A20, or may not be present, or the non-adhered portion a may be present only at one end of the columnar substrate A20. It is preferable that the columnar substrate A20 has non-adhered portions a at both ends.

[0017] In step 1, as shown in FIG. 2, 2-1, a thermoplastic film B30 is wrapped circumferentially around the outer periphery of the columnar substrate A, which has been preheated to 100°C to 200°C. At this time, as shown in FIG. 2, 2-2, the thermoplastic film B30 may be wrapped around the columnar substrate A20 so that the thermoplastic film B30 continuously covers the outer periphery of the columnar substrate A20. Since the thermoplastic film B30 is wrapped around the columnar substrate A20 in the circumferential direction one or more times, there are no gaps at both ends of the wrapped thermoplastic film B30, resulting in high sealing performance and excellent leak resistance. Furthermore, the thermoplastic film B may have tackiness. From the viewpoint of ease of handling, it is preferable that the thermoplastic film B has tackiness and be temporarily fixed to the columnar substrate A. Furthermore, the thermoplastic film B may be coated with an adhesive to the extent that it does not impair leak resistance, and then wrapped around the columnar substrate A and temporarily fixed. A commercially available adhesive may be used as the adhesive.

[0018] Because the thermoplastic film B30 is thermoplastic, it adheres tightly to the columnar substrate A20 without any gaps, as shown in 2-3 in Figure 2. By heating and melting and solidifying the thermoplastic film B before insert molding the resin C in the next step 2, the columnar substrate A and the thermoplastic film B can be more reliably bonded together, thereby improving the sealing performance and further improving the leak resistance. In addition, by applying pressure to the film surface when the film is heated and melted, the gap between the columnar substrate A and the thermoplastic film B can be reduced.

[0019] [Heat Melting and Solidification] The method for heating the columnar substrate A may be at least one method selected from the group consisting of contact heating, hot air heating, high-frequency induction heating, resistance heating, and infrared heating.

[0020] The heating temperature may be determined taking into consideration the heat resistance temperature of the material of the columnar substrate A, and is preferably 100 to 200°C, more preferably 120 to 180°C, and even more preferably 150 to 170°C. The time for heating the thermoplastic film B at the above temperature may be 0.1 to 120 seconds, 0.5 to 60 seconds, 1 to 30 seconds, or even 3 to 20 seconds. By heating at the above temperature for the above time, the thermoplastic film B is efficiently deformed and melted, and effectively wets and spreads across the bonding surface, resulting in a high bonding strength.

[0021] Methods for solidifying the heat-melted thermoplastic film B include a method of allowing it to cool at room temperature and a method of allowing it to cool using a cooling device. "Room temperature" refers to a general room temperature within the range of 5 to 30°C. Among these, the method of allowing it to cool at room temperature is preferred from the viewpoint of ease of production. In this specification, "solidified" means a solid at room temperature, i.e., no fluidity at 23°C under no pressure.

[0022] [Columnar Substrate A] The shape of the columnar substrate A is not particularly limited. The cross section of the columnar substrate A perpendicular to the longitudinal direction may be, for example, a circle, a semicircle, an ellipse, a square, a rectangle, a triangle, or other polygonal shapes. The polygon may be a regular polygon or a non-regular polygon. The columnar substrate A also includes a quadrangular pillar (strip) whose cross section is a rectangle with a large aspect ratio. Examples of the material of the columnar substrate A include metals and inorganic materials. The material of the columnar substrate A may be a single material, or two or more materials may be used in combination. From the viewpoints of conductivity, heat resistance, and strength, the columnar substrate A is preferably a metal. When the material of the columnar substrate A is a resin, the resin material must have a melting point or glass transition temperature that does not deform at the temperature used in the insert molding in step 2. The metal is not particularly limited, and examples thereof include aluminum, iron, copper, magnesium, titanium, etc. Furthermore, the surface of the metal may be metal-plated. In this embodiment, the term "iron" is used to include iron and its alloys. Examples of iron alloys include steel and stainless steel. Similarly, copper, aluminum, magnesium, and titanium are also used to include their simple substances and alloys.

[0023] The inorganic material is not particularly limited, and examples thereof include glass, ceramic, and carbon molded body. Examples of glass include general glass, heat-resistant glass, fireproof glass, fire-resistant glass, and chemically strengthened glass used for protecting smartphones. Specific examples include soda-lime glass, lead glass, borosilicate glass, and quartz glass. Examples of ceramics include fine ceramics used in semiconductors, automobiles, industrial equipment, and the like. Specific examples include oxide-based ceramics such as alumina, zirconia, and barium titanate; hydroxide-based ceramics such as hydroxyapatite; carbide-based ceramics such as silicon carbide; and nitride-based ceramics such as silicon nitride. Examples of resins used as the material for the columnar substrate A include cured products of thermosetting resins such as glass fiber reinforced thermosetting resins, epoxy resins, vinyl ester resins, and unsaturated polyesters; and highly heat-resistant engineering plastics such as polyimide resins, polyetherimides, and polyethersulfones.

[0024] (Pretreatment) The columnar substrate A is preferably subjected to a surface pretreatment for the purpose of removing surface contaminants and / or achieving an anchoring effect. Examples of pretreatment include degreasing, UV ozone treatment, blasting, polishing, plasma treatment, corona discharge treatment, laser treatment, etching, and flame treatment. Pretreatments include cleaning the surface of the columnar substrate A or roughening the surface. Specifically, when the columnar substrate A is made of aluminum, copper, glass, ceramic, or iron, at least one treatment selected from the group consisting of degreasing, UV ozone treatment, blasting, polishing, plasma treatment, and etching is preferred. When the columnar substrate A is made of FRP, polypropylene, polycarbonate, polymethyl methacrylate, polyetherimide, polyamide, or polybutylene terephthalate, at least one treatment selected from the group consisting of degreasing, UV ozone treatment, blasting, polishing, plasma treatment, and corona discharge treatment is preferred. Only one type of pretreatment may be used, or two or more types may be used. As specific methods for these pretreatments, known methods can be used.

[0025] The degreasing treatment is a method of removing dirt such as oil and grease from the surface of the columnar substrate A by dissolving it with an organic solvent such as acetone or toluene.

[0026] UV ozone treatment is a process that uses the energy of short-wavelength ultraviolet rays emitted from a low-pressure mercury lamp and the ozone (O ３ ) to clean or modify the surface. In the case of glass, it is a surface cleaning method that removes organic impurities from the surface. Generally, cleaning and surface modification equipment using low-pressure mercury lamps is called "UV ozone cleaner," "UV cleaning equipment," "ultraviolet surface modification equipment," etc.

[0027] Examples of blasting include wet blasting, shot blasting, sand blasting, etc. Among these, wet blasting is preferred because it can provide a denser surface than dry blasting.

[0028] Examples of the polishing treatment include buff polishing using an abrasive cloth, roll polishing using abrasive paper (sandpaper), and electrolytic polishing.

[0029] Plasma treatment involves creating a plasma beam using a high-voltage power supply and a rod, which is then struck against the surface of a material to excite the molecules and put them into a functional state. Examples of such treatments include atmospheric pressure plasma treatment, which can impart hydroxyl groups or polar groups to the surface of a material.

[0030] Corona discharge treatment is a method used to modify the surface of polymer films. Electrons emitted from an electrode cleave the polymer main chain or side chain in the polymer surface layer, generating radicals that generate hydroxyl groups or polar groups on the surface.

[0031] Laser treatment is a technique for improving the surface characteristics by rapidly heating and cooling only the surface of the columnar substrate A by irradiating it with a laser, and is an effective method for roughening the surface. Known laser treatment techniques can be used.

[0032] Examples of etching treatments include chemical etching treatments such as an alkali method, a phosphoric acid-sulfuric acid method, a fluoride method, a chromic acid-sulfuric acid method, and an iron chloride method, as well as electrochemical etching treatments such as an electrolytic etching method.

[0033] Flame treatment is a method of converting oxygen in the air into plasma by burning a mixture of combustion gas and air, and applying the oxygen plasma to an object to be treated, thereby making the surface hydrophilic. Known flame treatment techniques can be used.

[0034] [Thermoplastic film B] The thermoplastic film B is mainly composed of a thermoplastic resin. Furthermore, the thermoplastic film B preferably has adhesive properties to the columnar substrate A. The "main component" refers to the component with the highest content among the resin components in the thermoplastic film B. The thermoplastic film B 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. Furthermore, the "film" refers to a resin composition mainly composed of a thermoplastic resin molded into a thin film.

[0035] <<Y°C - X°C>> If the thermoplastic resin used in thermoplastic film B has a melting point, the melting point of thermoplastic film B is X°C. Alternatively, if the thermoplastic resin used in thermoplastic film B does not have a melting point, the temperature obtained by adding 70°C to the glass transition temperature is X°C. Let Y°C be the resin temperature during molding of resin C. 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, thermoplastic film B efficiently melts due to the heating by resin C during molding, effectively wetting and 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 temperature obtained by adding 70°C to the glass transition temperature is regarded as the melting point. The glass transition temperature means 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. Specifically, it is a value measured by the method described in the Examples.

[0036] <<Amorphous Thermoplastic Resin>> The thermoplastic film B is preferably composed primarily of an amorphous thermoplastic resin. An amorphous thermoplastic resin is a resin that has no crystals or only a small amount of crystals and has a heat of fusion of 15 J / g or less. The heat of fusion is calculated from the area of ​​the endothermic peak in a differential scanning calorimeter (DSC) and the weight of the thermoplastic resin component. When an inorganic filler or the like is contained in the film, the heat of fusion is calculated from the weight of the thermoplastic resin component excluding the inorganic filler. Specifically, 2 to 10 mg of a sample is weighed out, placed in an aluminum pan, and heated using a DSC (DSC8231 manufactured by Rigaku Corporation) from 23°C to 200°C or higher at a rate of 10°C / min to obtain a DSC curve. The heat of fusion can then be calculated from the area of ​​the endothermic peak upon melting determined from the DSC curve and the above-mentioned weighed value.

[0037] The heat of fusion of the amorphous thermoplastic resin is more preferably 11 J / g or less, even more preferably 7 J / g or less, and even more preferably 4 J / g or less, and it is particularly preferable that the melting peak is below the detection limit. By using a thermoplastic film B mainly composed of an amorphous thermoplastic resin having a heat of fusion of 15 J / g or less, the rapid viscosity decrease seen in conventional hot melt adhesives does not occur during heating, and the adhesive does not reach a low viscosity (0.001 to 100 Pa s) even at high temperatures exceeding 200 °C. Therefore, even in a molten state, the thermoplastic film B does not flow out from between the columnar substrate A and the resin C, ensuring a stable thickness of the thermoplastic film B and achieving a stable high bonding strength. In order to fully impart the properties of the amorphous thermoplastic resin to the thermoplastic film B, the content of the amorphous thermoplastic resin is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and most preferably 90% by mass or more of the resin components in the thermoplastic film B.

[0038] Furthermore, from the viewpoint of airtightness and toughness, the amorphous thermoplastic resin is preferably at least one of a thermoplastic epoxy resin and a phenoxy resin. Among these, from the viewpoint of airtightness and toughness, it is more preferable that the thermoplastic film B mainly comprises an amorphous thermoplastic resin, which is at least one of a thermoplastic epoxy resin and a phenoxy resin. Furthermore, from the viewpoint of airtightness and toughness, it is even more preferable that the thermoplastic film B mainly comprises an amorphous thermoplastic resin, which is at least one of a thermoplastic epoxy resin and a phenoxy resin, having an epoxy equivalent of 1,600 or more and a heat of fusion of 15 J / g or less. The above-mentioned "main component" refers to the component with the highest content among the resin components in the thermoplastic film B. The thermoplastic film B 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.

[0039] Thermoplastic epoxy resins and phenoxy resins have low cohesive strength within the resin and may contain hydroxyl groups, so they have strong interactions with the columnar substrate A and resin C, and are expected to be able to bond dissimilar materials with a stronger bonding strength than conventional crystalline hot melt adhesives.

[0040] In particular, from the viewpoint of storage stability, it is preferable that the thermoplastic film B has an epoxy equivalent of 1,600 g / eq. or more or is a thermoplastic resin that does not contain epoxy groups. The epoxy equivalent is more preferably 2,000 g / eq. or more, even more preferably 5,000 g / eq. or more, and even more preferably 9,000 g / eq. or more, and is particularly preferably above the detection limit so that epoxy groups are not substantially detected. Note that an epoxy equivalent of above the detection limit means that no epoxy groups are detected when the epoxy equivalent is measured according to JIS K 7236:2001, which will be described later. The epoxy equivalent (weight of the thermoplastic resin containing 1 mole of epoxy groups) referred to here is the epoxy equivalent value of the thermoplastic resin contained in the thermoplastic film B before bonding, and is a value (unit: "g / eq.") measured according to the method specified in JIS-K7236:2001. Specifically, a potentiometric titrator was used to add tetraethylammonium bromide acetate solution, and a 0.1 mol / L perchloric acid-acetic acid solution was used. The solvent-diluted product (resin varnish) was then titrated using a 0.1 mol / L perchloric acid-acetic acid solution, and the solids content was calculated from the nonvolatile content. In the case of a mixture of two or more resins, the value can also be calculated from the content and epoxy equivalent of each resin.

[0041] <<Thermoplastic Epoxy Resin>> The thermoplastic epoxy resin is preferably 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 isocyanato group, and a cyanate ester group. By using such a compound, the polymerization reaction to form a linear polymer proceeds preferentially, making it possible to obtain a thermoplastic epoxy resin having the desired properties.

[0042] (a) Bifunctional epoxy resin monomer or oligomer refers to an epoxy resin monomer or oligomer having two epoxy groups in the molecule. Specific examples of (a) bifunctional epoxy resin monomer or oligomer include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bifunctional phenol novolac type epoxy resin, bisphenol AD ​​type epoxy resin, biphenyl type epoxy resin, bifunctional naphthalene type epoxy resin, bifunctional alicyclic epoxy resin, bifunctional glycidyl ester type epoxy resin (e.g., diglycidyl phthalate, diglycidyl tetrahydrophthalate, dimer acid diglycidyl ester, etc.), bifunctional glycidyl amine type epoxy resin (e.g., diglycidyl aniline, diglycidyl toluidine, etc.), bifunctional heterocyclic epoxy resin, bifunctional diarylsulfone type epoxy resin, hydroquinone type epoxy resin (e.g., hydroquinone diglycidyl ether, etc.), , 2,5-di-tert-butylhydroquinone diglycidyl ether, resorcinol diglycidyl ether, etc.), bifunctional alkylene glycidyl ether compounds (for example, butanediol diglycidyl ether, butenediol diglycidyl ether, butynediol diglycidyl ether, etc.), bifunctional glycidyl group-containing hydantoin compounds (for example, 1,3-diglycidyl-5,5-dialkylhydantoin, 1-glycidyl-3-(glycidoxyalkyl)-5,5-dialkylhydantoin, etc.), bifunctional glycidyl group-containing siloxanes (for example, 1,3-bis(3-glycidoxypropyl)-1,1,3,3-tetramethyldisiloxane, α,β-bis(3-glycidoxypropyl)polydimethylsiloxane, etc.), and modified products thereof. Of these, bisphenol A type epoxy resins, bisphenol F type epoxy resins, and biphenyl type epoxy resins are preferred in terms of reactivity and workability.

[0043] Examples of (b) bifunctional compounds having a phenolic hydroxyl group include mononuclear aromatic dihydroxy compounds having one benzene ring, such as catechol, resorcinol, and hydroquinone; bisphenols such as bis(4-hydroxyphenyl)propane (bisphenol A), bis(4-hydroxyphenyl)methane (bisphenol F), and bis(4-hydroxyphenyl)ethane (bisphenol AD); compounds having a condensed ring, such as dihydroxynaphthalene; bifunctional phenol compounds having an allyl group, such as diallyl resorcinol, diallyl bisphenol A, and triallyl dihydroxybiphenyl; and dibutyl bisphenol A. Specific examples of (b) carboxyl group-containing compounds include adipic acid, succinic acid, malonic acid, cyclohexanedicarboxylic acid, phthalic acid, isophthalic acid, and terephthalic acid. Examples of (b) bifunctional compounds having a mercapto group include ethylene glycol bisthioglycolate and ethylene glycol bisthiopropionate. Specific examples of (b) isocyanato group-containing bifunctional compounds include diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HMDI), and tolylene diisocyanate (TDI). Specific examples of (b) cyanate ester group-containing bifunctional compounds include 2,2-bis(4-cyanatophenyl)propane, 1,1-bis(4-cyanatophenyl)ethane, and bis(4-cyanatophenyl)methane.

[0044] Among the bifunctional compounds (b) above, bifunctional compounds having a phenolic hydroxyl group are preferred from the viewpoint of obtaining a thermoplastic polymer, bifunctional compounds having two phenolic hydroxyl groups and a bisphenol structure or a biphenyl structure are preferred from the viewpoint of heat resistance and bondability, and bisphenol A, bisphenol F, or bisphenol S are preferred from the viewpoint of heat resistance and cost.

[0045] When (a) is a bisphenol A epoxy resin, a bisphenol F epoxy resin, a bisphenol S epoxy resin, or a biphenyl epoxy resin, and (b) is bisphenol A, bisphenol F, or bisphenol S, the polymer obtained by polymerization of (a) and (b) has a main chain structure consisting of a paraphenylene structure and an ether bond, connected by an alkylene group, and a structure in which hydroxyl groups generated by polyaddition are arranged in side chains. The linear structure consisting of the paraphenylene skeleton can increase the mechanical strength of the polymer after polymerization, and the hydroxyl groups arranged in the side chains can improve adhesion to substrates. As a result, high bonding strength can be achieved while maintaining the workability of thermosetting resins. Furthermore, in the case of a thermoplastic resin, recycling and repair are possible by softening and melting with heat, improving the recyclability and repairability that are problems with thermosetting resins.

[0046] Phenoxy Resin Phenoxy resin is a polyhydroxypolyether synthesized from bisphenols and epichlorohydrin and has thermoplastic properties. Known methods for producing phenoxy resin include a method involving a direct reaction between a dihydric phenol and epichlorohydrin and a method involving an addition polymerization reaction between a diglycidyl ether of a dihydric phenol and a dihydric phenol. The phenoxy resin used in this embodiment may be obtained by either method. In the case of a direct reaction between a dihydric phenol and epichlorohydrin, examples of the dihydric phenol include phenols such as bisphenol A, bisphenol F, bisphenol S, biphenol, biphenylenediol, and fluorenediphenyl; and aliphatic glycols such as ethylene glycol, propylene glycol, and diethylene glycol. Among these, bisphenol A, bisphenol F, and bisphenol S are preferred from the viewpoints of cost, bondability, viscosity, and heat resistance. These may be used alone or in combination of two or more. Phenoxy resin has a chemical structure similar to that of epoxy resin, with a main skeleton consisting of a paraphenylene structure and an ether bond, a main chain connecting these, and hydroxyl groups arranged in side chains.

[0047] Physical Properties of Thermoplastic Epoxy Resins and Phenoxy Resins Thermoplastic epoxy resins and phenoxy resins preferably have a weight-average molecular weight (MW) of 10,000 to 500,000, more preferably 18,000 to 300,000, and even more preferably 20,000 to 200,000, as measured by gel permeation chromatography (GPC) in terms of polystyrene. The MW is calculated from the elution peak position detected by GPC, and each MW is a standard polystyrene-equivalent molecular weight. A MW within this range provides a good balance between thermoplasticity and heat resistance, allowing efficient production of bonded structures by heat melting, and the resulting bonded structures also have high heat resistance. A MW of 10,000 or higher provides excellent heat resistance, while a MW of 500,000 or lower provides low viscosity during heat melting and high bondability.

[0048] <<Components other than the resin component in the thermoplastic film B>> If necessary, the thermoplastic film B may contain a filler or an additive as a component other than the resin component, as long as the object of the present embodiment is not impaired.

[0049] Examples of fillers include inorganic fillers and organic fillers (such as resin powders). Examples of inorganic fillers include spherical fused silica, metal powders of metals such as iron, silica sand, talc, calcium carbonate, mica, acid clay, diatomaceous earth, kaolin, quartz, titanium oxide, silica, phenolic resin microballoons, and glass balloons. When thermoplastic film B contains a filler, the content of the filler in 100% by volume of the total amount of thermoplastic film B is preferably 50% by volume or less, more preferably 30% by volume or less, even more preferably 20% by volume or less, and most preferably 10% by volume or less. The volume of the filler can be determined by dividing the weight of the filler contained in thermoplastic film B by the apparent specific gravity of the filler. The content of the resin component in the total amount (100% by volume) of the thermoplastic film B is preferably 10% by volume or more, more preferably 20% by volume or more, even more preferably 30% by volume or more, and even more preferably 50% by volume or more, and in one embodiment 80% by volume or more, in another embodiment 90% by volume or more, and in another embodiment 99% by volume or more.

[0050] Examples of additives include antifoaming agents, coupling agents such as silane coupling agents, pigments, tackifying resins, etc., and these may be contained alone or in combination of two or more. The content of additives in thermoplastic film B is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less. The content of resin components in thermoplastic film B is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and even more preferably 50% by mass or more, and in one embodiment 80% by mass or more, in another embodiment 90% by mass or more, and in another embodiment 99% by mass or more.

[0051] <<Configuration of Thermoplastic Film B>> The thermoplastic film B is a sheet-like product. The width of the thermoplastic film B in the direction perpendicular to the circumferential direction of the columnar substrate A is preferably 3 to 30 mm. The width of the thermoplastic film B is indicated by b in FIG. 1. From the viewpoint of obtaining a firmly bonded bonded body in a short bonding process time, the width of the thermoplastic film B is more preferably 25 mm or less, and even more preferably 20 mm or less. From the same viewpoint, the width of the thermoplastic film B is more preferably 4 mm or more, and even more preferably 5 mm or more.

[0052] The thickness of the thermoplastic film B is preferably 10 μm or more and 3 mm or less. The thickness of the thermoplastic film B is indicated by c in FIG. 2. From the viewpoint of obtaining a firmly bonded bonded body in a short bonding process time, the thickness of the thermoplastic film B is more preferably 1 mm or less, even more preferably 0.5 mm or less, even more preferably 0.3 mm or less, particularly preferably 0.2 mm or less, and most preferably 0.1 mm or less. Furthermore, from the viewpoint of further improving adhesion and leak resistance, the thickness of the thermoplastic film B is more preferably 20 μm or more, even more preferably 30 μm or more, and particularly preferably 40 μm or more. When the thickness of the thermoplastic film B is within the above numerical range, it can be efficiently spread over the bonding surface with the columnar substrate A by heating, etc., resulting in high bonding strength and leak resistance.

[0053] The thermoplastic film B may be a single layer or a laminate consisting of multiple layers, but from the viewpoints of ease of production and improved bonding strength, it is preferable that the thermoplastic film B be a single layer.

[0054] Furthermore, the thermoplastic film B may have tackiness as described above, as long as it does not impair leak resistance. Tackiness can be imparted by mixing a tackifier resin into the thermoplastic resin constituting the thermoplastic film B, or by applying a pressure-sensitive adhesive to the surface of the thermoplastic film B. Tackiness may be imparted to one or both sides, but applying it to one side is preferable because only the surface in contact with the columnar substrate A has tackiness, making it less likely for the adhesive surface to be exposed to the outside. The pressure-sensitive adhesive may be applied to the entire surface, or it may be applied partially in a striped, dotted, lattice, or tiled pattern (a shape in which multiple squares are arranged with gaps between them). A small application area is preferable because the pressure-sensitive adhesive is less likely to protrude and be exposed from the edge of the thermoplastic film B, making it less likely for leak resistance to be reduced. Furthermore, the tackiness may be imparted to a small amount sufficient to provide anti-slip properties. In other words, when the thermoplastic film B is wrapped around the columnar substrate A, the thermoplastic film B may not stick to the columnar substrate A, but may be sufficient to increase resistance (become less slippery) when a shear force is applied. A lower tackiness is preferred as it tends to increase adhesive strength and provide excellent leak resistance.

[0055] <<Method for Producing Thermoplastic Film B>> The method for producing thermoplastic film B is not particularly limited. The method for producing thermoplastic film B may include a step of removing the solvent from a resin composition dissolved in a solvent to form a film. For example, a resin composition may be obtained by heating and polymerizing a monomer or oligomer of a bifunctional epoxy compound, and then adding a solvent to the obtained resin composition as needed, applying the resin composition to a release film or the like, curing and drying, and applying pressure as needed to obtain thermoplastic film B. The polymerization reaction may be carried out after application to a release film, after the solvent is removed to obtain a film shape, or a combination thereof.

[0056] [Step 2] In step 2, the portion of the columnar substrate A to which the thermoplastic film B is bonded is bonded with the resin C by insert molding, thereby sealing.

[0057] [Insert Molding] Insert molding can be performed using conventionally known methods. An example of an embodiment of step 2 will be described with reference to FIGS. 3 and 4. FIG. 3 is an explanatory diagram of step 2 showing cross sections of the film-attached substrate and mold obtained in step 1. FIG. 4 is a cross-sectional view of a bonded structure cut parallel to the width direction. As shown in FIG. 3, a film-attached substrate 1, in which a thermoplastic film B30 is wrapped around a columnar substrate A20 obtained in step 1, is placed in the cavity of an insert molding mold 50, and resin C40a molten by heating and pressurization is filled in. Specifically, after placing the film-attached substrate 1 in the cavity of the insert molding mold 50 (FIG. 3), resin C40a is injected and filled into the cavity through a resin injection port provided in the mold. At this time, insert molding is performed so that resin C is bonded to at least a portion, preferably all, of the thermoplastic film B30 of the film-attached substrate 1, and the substrate is removed from the mold 50. By performing step 2, as shown in FIG. 4, a bonded body 10 is produced in which the columnar substrate A20 is sealed with the resin C40 via the thermoplastic film B30.

[0058] There are no particular limitations on the mold used for insert molding, and conventional molds can be used. The mold can be heated or cooled as needed. The gate used to introduce resin C into the cavity can be of various types, such as a direct gate, disk gate, side gate, fan gate, film gate, or tunnel gate, depending on the shape of the bonded body.

[0059] [Resin C] In this embodiment, Resin C is used as a sealing material. Resin C is not particularly limited as long as it can be insert-molded, but is preferably one selected from the group consisting of thermoplastic resins, thermosetting resins, and fiber-reinforced plastics (FRP). Among these, from the viewpoints of bonding strength, cost, and ease of molding, Resin C is preferably a thermoplastic resin. Examples of thermoplastic resins include polyolefins and acid-modified products thereof, polystyrene, polymethyl methacrylate, AS resin, ABS resin, thermoplastic aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate, polyimide, polyamide, polyamideimide, polyetherimide, polyethersulfone, polyphenylene ether and modified products thereof, polyphenylene sulfide, polyoxymethylene, polyarylate, polyether ketone, polyether ether ketone, polyether ketone ketone, thermoplastic epoxy, and fiber-reinforced materials thereof. Examples of thermosetting resins that can be used include at least one selected from epoxy resins, vinyl ester resins, phenolic resins, urethane resins, and the like. From the viewpoints of heat resistance, bonding strength, cost, ease of molding, etc., it is preferable that the material be at least one selected from polycarbonate, glass fiber reinforced polyamide, glass fiber reinforced polybutylene terephthalate, and glass fiber reinforced polyphenylene sulfide.

[0060] The molding temperature (resin temperature) of Resin C 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 thermoplastic film B is efficiently deformed and melted by heating, and effectively wets and spreads over the bonding surface, resulting in high bonding strength.

[0061] There is no particular limitation on the combination of the material of the columnar substrate A and the resin C. In the bonded structure of this embodiment, the thickness of the resin C (sealing material) is not particularly limited, and can be appropriately set according to the application within a range that provides excellent bonding strength and leak resistance.

[0062] <Jointed Body> An example of a joined body manufactured by the joined body manufacturing method of this embodiment will be described with reference to FIG. 5 . FIG. 5 is a cross-sectional view of a cut surface parallel to the longitudinal direction of the joined body. As shown in FIG. 5 , the joined body 10 is formed by sealing a columnar substrate A20 with a resin C40 via a thermoplastic film B30. The thermoplastic film B30 provides excellent bonding strength and adhesion between the columnar substrate A20 and the resin C40. This prevents air from entering or exiting the sealed portion surrounded by the solid line, thereby achieving leak resistance.

[0063] The bonded structure of this embodiment exhibits excellent bond strength even when it is a bonded structure of dissimilar materials. The bond strength is affected by many factors, such as the thickness of the thermoplastic film B, the molecular weight and chemical structure of the polymer constituting the thermoplastic film B, the mechanical properties, and the viscoelastic properties, in addition to the strength of the interfacial interactions acting between the thermoplastic film B and the columnar substrate A and between the thermoplastic film B and the resin C. Therefore, the details of the mechanism by which the bonded structure of this embodiment exhibits excellent bond strength and leak resistance are not clear.

[0064] In a more preferred embodiment of the bonded body, the thermoplastic film B is primarily composed of an amorphous thermoplastic resin, which is at least one of a thermoplastic epoxy resin and a phenoxy resin. Although the details of the mechanism by which this more preferred embodiment exhibits superior bonding strength and leak resistance are not clear, it is presumed that the main factors are the low cohesive force within the amorphous thermoplastic resin and, when hydroxyl groups are present in the resin, the formation of chemical bonds or intermolecular forces, such as hydrogen bonds or van der Waals forces, at the interface between the thermoplastic film B and the columnar substrate A and at the interface between the thermoplastic film B and the resin C.

[0065] However, in the bonded structure of this embodiment, the state or characteristics of the interface between the thermoplastic film B and the columnar substrate A, and the interface between the thermoplastic film B and the resin C are extremely thin chemical structures on the nanometer level or less, making them difficult to analyze. Therefore, it is impossible or impractical with current technology to identify the state or characteristics of the above interfaces to distinguish them from those that do not use the thermoplastic film B.

[0066] In a more preferred embodiment, for example, when a leak test is performed by applying an air pressure of 0.1 MPaG to the sealed portion of the bonded body, the air leakage rate is preferably 1 mL / min or less. Furthermore, the bonded body of this embodiment can effectively relieve stress during thermal cycling. Therefore, in an even more preferred embodiment, for example, when the bonded body is heated to 160°C, maintained at that temperature for 1000 minutes, cooled to 23°C, and then subjected to the leak test, the air leakage rate is preferably 1 mL / min or less. Specifically, the leak rate is a value measured by the leak test described in the Examples. The bonded body of this embodiment has a strong bond between the columnar substrate A and the resin C, is resistant to peeling during thermal cycling, and has excellent leak resistance, making it suitable for use in applications where these properties can be exhibited. For example, an electrical or electronic component including the bonded body of this embodiment can be provided. More specifically, as shown in FIG. 5 , the joined body 10 of the present embodiment is formed by covering and sealing the entire thermoplastic film B30 on the columnar substrate A20 with a resin C40, and can be used in automobiles and electric / electronic parts such as terminal blocks, bus bars, and electric elements.

[0067] Hereinafter, the present embodiment will be specifically described with reference to examples and comparative examples, but the present embodiment is not limited to these.

[0068] In the examples and comparative examples, a bonded body was produced by bonding a columnar substrate A, a thermoplastic film B or a bonding agent, and a resin C in this order. Hereinafter, the layer made of the thermoplastic film B or the bonding agent will be referred to as an intermediate layer. In the examples and comparative examples, the following materials were used. <Columnar substrate A> C1100 (tough pitch copper) with a width of 12.4 mm, a length of 64.9 mm, and a thickness of 1.6 mm <Thermoplastic film B> Films P-1 to P-8 produced in examples 1 to 8 <Bonding agent> Bonding agents Q-1 to Q-5 produced in comparative examples 1 to 5 <Resin C> Polyphenylene sulfide (containing 30% by mass of GF)

[0069] <Weight-average molecular weight, heat of fusion, melting point, and epoxy equivalent of thermoplastic film B and adhesive> (Weight-average molecular weight) Thermoplastic film B or the adhesive was dissolved in tetrahydrofuran, and measured under the following conditions using Prominence 501 (manufactured by Showa Science Co., Ltd., Detector: Shodex (registered trademark) RI-501 (manufactured by Showa Denko K.K.)). Thermoplastic resins that do not dissolve in tetrahydrofuran were excluded from the measurement. Column: LF-804 x 2 (manufactured by Showa Denko K.K.) Column temperature: 40°C Sample: 0.4 mass% resin solution in tetrahydrofuran Flow rate: 1 ml / min Eluent: tetrahydrofuran Calibration method: conversion using standard polystyrene

[0070] (Heat of Fusion, Melting Point, and Glass Transition Temperature) 2 to 10 mg of thermoplastic film B and the bonding agent were weighed, placed in an aluminum pan, and heated from 23°C to 200°C at 10°C / min using a DSC (DSC8231, manufactured by Rigaku Corporation) to obtain a DSC curve. The heat of fusion was calculated from the area of ​​the endothermic peak during melting in the DSC curve and the weighed value. The melting peak temperature of the obtained DSC curve was taken as the melting point (X°C). If a melting peak was not obtained or if the heat of fusion was 15 J / g or less, the melting point (X°C) was determined by adding 70°C to the glass transition temperature. The glass transition temperature was determined as the temperature at which the DSC curve began to drop in the second cycle, after heating to 200°C using a DSC, cooling to 40°C or less, and further heating to 200°C. For thermosetting resins that do not melt upon heating, no melting point was recorded.

[0071] (Epoxy equivalent) Measured according to JIS K-7236:2001 and converted into a value as a resin solid content. In the case of a simple mixture not involving a reaction, it was calculated from the epoxy equivalent and content of each.

[0072] <Y-X (°C)> The melting points of the thermoplastic film B and the bonding agent were set to X°C, and the resin temperature during injection molding of the resin C was set to Y°C. The value (Y°C-X°C) was calculated by subtracting X°C from Y°C.

[0073] Example 1 (Film P-1) A reactor equipped with a stirrer, reflux condenser, gas inlet tube, and thermometer was charged with 1.0 equivalent (203 g) of jER (registered trademark) 1007 (Mitsubishi Chemical Corporation, bisphenol A-type epoxy resin, weight-average molecular weight approximately 10,000), 1.0 equivalent (12.5 g) of bisphenol S, 2.4 g of triphenylphosphine, and 1,000 g of methyl ethyl ketone. The mixture was heated to 100°C with stirring under a nitrogen gas atmosphere. After visually confirming dissolution, the mixture was cooled to 40°C to obtain a thermoplastic epoxy resin composition with a solids content of approximately 20% by weight. The resin composition was applied to a release-treated polyethylene terephthalate film (thickness 100 μm) and then heated at 160°C for 2 hours to remove the solvent, yielding Film P-1 with a solids content of 100% by weight, a length of 32 to 33 mm, and the thickness and width shown in Table 1. (Step 1) Columnar substrate A was heated at the heating temperature and heating time shown in Table 1. Film P-1 was wrapped around the outer periphery of columnar substrate A, which had been heated to 160°C, once to create a 2-3 mm lap. Figure 6 is a schematic diagram of a bonded structure for illustrating the example. As shown in (6-1) in Figure 6, a non-bonded portion a of film P-1 (B in Figure 6) was provided, and film P-1 was wrapped around columnar substrate A to melt film P-1. Thereafter, film P-1 was allowed to cool at room temperature for 1 minute to solidify, resulting in a film-attached substrate in which columnar substrate A and film P-1 were bonded. The operating method of this step 1 is shown in Table 1 as "winding method 1." (Step 2) Using an injection molding machine (manufactured by Toyo Machinery & Metal Co., Ltd., model name "Si-100-6s") and a molding die, resin C was insert molded and bonded to the portion of the film-attached substrate where film P-1 was wrapped, thereby obtaining a bonded body of columnar substrate A and resin C. The insert molding conditions were injection molding temperature (resin temperature) 300 ° C, mold temperature 135 ° C, injection speed 15 mm / sec, injection pressure 130 MPa, dwell pressure 70 MPa, dwell time 4 seconds, and cooling time 30 seconds. Figure 6 (6-2) shows a schematic diagram of the bonded body of columnar substrate A and resin C obtained by step 2.

[0074] [Examples 2 to 3] (Films P-2 to P-3) Films P-2 to P-3 were obtained in the same manner as in Example 1, except that the thickness and width of the film were changed to the values ​​shown in Table 1. (Steps 1 and 2) Steps 1 and 2 were performed in the same manner as in Example 1, except that the above-mentioned films were used, to obtain a bonded body of columnar substrate A and resin C.

[0075] Example 4 (Film P-4) 20 g of PhenoToto (registered trademark) YP-50S (Nippon Steel Chemical & Material Co., Ltd., phenoxy resin, weight-average molecular weight approximately 50,000) and 80 g of cyclohexanone were charged into a reactor equipped with a stirrer, reflux condenser, gas inlet tube, and thermometer, and the temperature was raised to 60°C while stirring. After visually confirming dissolution, the mixture was cooled to 40°C to obtain a phenoxy resin composition with a solids content of 20% by mass. The resin composition was applied to a release-treated polyethylene terephthalate film (thickness 100 μm) and then heated at 160°C for 30 minutes to remove the solvent, yielding Film P-4 with a solids content of 100% by mass, a length of 33 mm, and the thickness and width shown in Table 1. (Steps 1 and 2) Steps 1 and 2 were carried out in the same manner as in Example 1, except that Film P-4 was used, to obtain a bonded structure of columnar substrate A and resin C.

[0076] [Example 5] (Film P-5) Film P-5 was obtained in the same manner as in Example 4, except that the film width was set to 10 mm. (Steps 1 and 2) Step 1 (winding method 1) and step 2 were performed in the same manner as in Example 1, except that film P-5 was used, to obtain a bonded body of columnar substrate A and resin C.

[0077] [Example 6] (Film P-6) Film P-6 was obtained in the same manner as in the production of film P-4 in Example 4, except that a tackifier resin (Tamanol 803L, manufactured by Arakawa Chemical Industries, Ltd.) was added in an amount of 5% by mass (solid content equivalent). (Steps 1 and 2) Steps 1 and 2 were carried out in the same manner as in Example 1, except that film P-6 was used, to obtain a bonded body of columnar substrate A and resin C. Film P-6 has tackiness and is temporarily fixed to columnar substrate A.

[0078] [Example 7] (Film P-7) Film P-7 was obtained in the same manner as in the production of film P-4 in Example 4, except that 10% by mass (solid content equivalent) of a tackifier resin (YS Polystar K125, manufactured by Yasuhara Chemical Co., Ltd.) was added. (Steps 1 and 2) Steps 1 and 2 were performed in the same manner as in Example 1, except that film P-7 was used, to obtain a bonded body of columnar substrate A and resin C.

[0079] Example 8 (Film P-8) The solid content (pellet form) of PhenoTohto (registered trademark) YP-50S (Nippon Steel Chemical & Material Co., Ltd., phenoxy resin, weight-average molecular weight approximately 50,000) was sandwiched between two release-treated polyethylene terephthalate films (thickness 100 μm), heated and pressurized at 200°C and 1 MPa for 10 seconds in a heat press, and allowed to cool at room temperature to obtain Film P-8 with a solid content of 100% by mass, a length of 33 mm, and the thickness and width shown in Table 1. Voids of 0.1 to 1 mm were generated in the film. (Steps 1 and 2) Steps 1 and 2 were performed in the same manner as in Example 1, except that Film P-8 was used, to obtain a bonded body of columnar substrate A and resin C.

[0080] [Comparative Example 1] (Bonding Agent Q-1) A reactor equipped with a stirrer, reflux condenser, gas inlet tube, and thermometer was charged with 1.0 equivalent (285 g) of jER (registered trademark) 1001 (Mitsubishi Chemical Corporation, bisphenol A type epoxy resin, molecular weight approximately 900), 1.0 equivalent (63 g) of Shounol (registered trademark) BRG-556 (Aica Kogyo Co., Ltd., novolac type phenolic resin), 1.4 g of triphenylphosphine, and 650 g of methyl ethyl ketone, and the mixture was heated to 100 ° C. while stirring under a nitrogen gas atmosphere. After visually confirming that the mixture had dissolved, the mixture was cooled to 40 ° C. to obtain a thermosetting epoxy resin solution (bonding agent Q-1) with a solids content of 20% by mass. (Step 1) The bonding agent Q-1 was applied to the columnar substrate A and heated to 160 ° C. for 30 minutes to harden the bonding agent. After that, the mixture was cooled to room temperature to form an intermediate layer made of bonding agent Q-1. The columnar substrate A was provided with a non-adhered portion of the adhesive, as in Example 1. The width of the intermediate layer is as shown in Table 2. The operating method of this step 1 is shown in Table 2 as "coating method." (Step 2) As in step 2 of Example 1, resin C was insert-molded and bonded to obtain a bonded body of columnar substrate A and resin C.

[0081] [Comparative Example 2] (Bonding Agent Q-2) A reactor equipped with a stirrer, reflux condenser, gas inlet tube, and thermometer was charged with 1.0 equivalent (285 g) of jER (registered trademark) 1001 (Mitsubishi Chemical Corporation, bisphenol A type epoxy resin, molecular weight approximately 900), 1.0 equivalent (63 g) of Shounol (registered trademark) BRG-556 (Aica Kogyo Co., Ltd., novolac type phenolic resin), 1.4 g of triphenylphosphine, and 650 g of methyl ethyl ketone, and the mixture was heated to 100 ° C. while stirring under a nitrogen gas atmosphere. After visually confirming that the mixture had dissolved, the mixture was cooled to 40 ° C. to obtain a thermosetting epoxy resin solution with a solids content of 20% by mass. The thermosetting epoxy resin solution having a solid content of 20% by mass was applied to a release-treated polyethylene terephthalate film (thickness: 100 μm), and then heated at 160° C. for 2 hours to remove the solvent and cure the film, thereby obtaining bonding agent Q-2, which is a film having a solid content of 100% by mass, a length of 33 mm, and the thickness and width shown in Table 2. (Steps 1 and 2) Steps 1 and 2 were carried out in the same manner as in Example 1, except that film Q-2 was used, to obtain a bonded body of columnar substrate A and resin C.

[0082] [Comparative Example 3] (Bonding Agent Q-3) A reactor equipped with a stirrer, reflux condenser, gas inlet tube, and thermometer was charged with 1.0 equivalent (203 g) of jER (registered trademark) 1007 (Mitsubishi Chemical Corporation, bisphenol A-type epoxy resin, molecular weight approximately 10,000), 1.0 equivalent (12.5 g) of bisphenol S, 2.4 g of triphenylphosphine, and 1,000 g of methyl ethyl ketone, and stirred at room temperature to obtain a solution of amorphous thermoplastic epoxy resin (bonding agent Q-3) with a solids content of approximately 20% by mass. (Steps 1 and 2) In step 1 (coating method), the bonding agent Q-3 was applied to the columnar substrate A and heated at 160 ° C. for 120 minutes to harden the bonding agent. Except for this, the same procedure as in Comparative Example 1 was carried out to obtain a bonded body of columnar substrate A and resin C.

[0083] [Comparative Example 4] (Bonding Agent Q-4) A reactor equipped with a stirrer, reflux condenser, gas inlet tube, and thermometer was charged with 0.05 equivalents (98 g) of jER (registered trademark) 1007 (Mitsubishi Chemical Corporation, bisphenol A-type epoxy resin, weight-average molecular weight approximately 10,000), 0.95 equivalents (238 g) of PG-100 (Osaka Gas Chemicals Co., Ltd., fluorene-based epoxy resin), 1.0 equivalent (125 g) of bisphenol S, 2 g of triphenylphosphine, and 1,000 g of methyl ethyl ketone. The mixture was heated to 100 ° C. under a nitrogen gas atmosphere while stirring. After visually confirming that the mixture had dissolved, the mixture was cooled to 40 ° C. to obtain a solution of an amorphous thermoplastic epoxy resin with a solids content of approximately 35% by mass (Bonding Agent Q-4). Note that the weight-average molecular weight and epoxy equivalent of bonding agent Q-4 could not be measured because it was partially insoluble in the solvent. (Steps 1 and 2) In step 1 (coating method), the bonding agent Q-4 was applied to the columnar substrate A, and the columnar substrate A was heated at 120°C for 60 minutes, and then heated at 180°C for 120 minutes. Except for this, the same procedure as in Comparative Example 1 was repeated to obtain a bonded body of the columnar substrate A and the resin C.

[0084] [Comparative Example 5] (Film Q-5) Film Q-5 was obtained in the same manner as in Example 1. (Step 1) Next, film Q-5 was wrapped around columnar substrate A once to create a lapped portion of 2 to 3 mm. A non-adhered portion of the film was provided on columnar substrate A in the same manner as in Example 1. Next, the portion of film Q-5 wrapped around columnar substrate A was fixed with a clip, and heated at the heating temperature and heating time shown in Table 1 to melt film Q-5. Thereafter, film Q-5 was allowed to cool at room temperature for 1 minute to solidify, resulting in a film-attached substrate in which columnar substrate A and film Q-5 were bonded. The operating method of this step 1 is shown in Table 2 as "winding method 2." (Step 2) As in step 2 of Example 1, resin C was insert-molded and bonded to obtain a bonded body of columnar substrate A and resin C.

[0085] <Workability> Workability was evaluated from the perspective of the bonding process time required for step 1 and ease of handling. When a film was used in step 1, the bonding process time was shorter than when a solution was used, and no dripping occurred, so the intermediate layer could be formed easily. In winding method 1, winding and melting were carried out simultaneously, so the process time was shorter than in winding method 2. <Evaluation criteria> A: Workability was "good". B: Workability was "poor" compared to A. C: Workability was extremely poor compared to A and "poor".

[0086] <Leak Test> As shown in Figure 6 (6-3), a hose H was inserted into the assembly produced in each Example and Comparative Example. A silicone resin adhesive was applied to the joint between the resin C and the hose H and the surrounding area to seal the joint. A plug coupler was attached to the end of the hose H to which the assembly was not attached and connected to a compressor. The entire assembly at the end of the hose to which the assembly was attached was submerged in water, and air X was pumped into the hose H at an air pressure of 0.1 MPaG toward the assembly. The leaking air bubbles in the water were visually observed. This procedure was performed on 10 assembly samples produced in each Example and Comparative Example. The adhesion between the columnar substrate A and the resin C was evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 1 and 2. When no air bubbles were observed in the water, the air leakage rate was considered to be 1 ml / min or less. <Evaluation Criteria> A: No air bubbles were observed 10 times out of 10 tests. B: No air bubbles were observed 8 to 9 times out of 10 tests. C: No bubbles were observed 5 to 7 times out of 10. D: No bubbles were observed 0 to 4 times out of 10.

[0087] <Leakage Test After Thermal Cycles> The bonded bodies manufactured in each of the Examples and Comparative Examples were subjected to 100 thermal cycles in which they were alternately placed in an atmosphere of 125°C and -40°C, and then the above-mentioned leakage test was carried out. The evaluation criteria were the same as those for the above-mentioned leakage test.

[0088] <Leakage test after heat resistance treatment> The bonded bodies manufactured in each of the examples and comparative examples were left standing in an oven at 160°C for 1000 hours, and then allowed to cool before undergoing the above-mentioned leakage test. The evaluation criteria were the same as those for the above-mentioned leakage test.

[0089]

[0090]

[0091] The manufacturing method and bonded body of this embodiment can be used for applications such as terminals, bus bars, and electric elements for automobiles and electric / electronic parts, but is not particularly limited to these exemplified applications.

[0092] 1. Substrate with film 10. Bonded body of this embodiment 20. Columnar substrate A 30. Thermoplastic film B 40. , 40a. Resin C 50. Mold a. Non-bonded portion b. Width of thermoplastic film B c. Thickness of thermoplastic film B H. Hose X. Air

Claims

1. A method for manufacturing a bonded body obtained by bonding a columnar substrate A, a thermoplastic film B, and a resin C in this order, comprising heating and melting and then solidifying the thermoplastic film B disposed on at least a part of the outer periphery of the columnar substrate A to bond the columnar substrate A and the thermoplastic film B, and bonding the portion of the columnar substrate A where the thermoplastic film B is disposed and the resin C by insert molding to seal the thermoplastic film B, wherein the heating and melting is performed by bringing the thermoplastic film B into contact with the columnar substrate A that has been pre-heated.

2. The method for manufacturing a bonded body according to claim 1, wherein the heating and melting is performed at 100 to 200 °C.

3. The method for manufacturing a bonded body according to claim 1 or 2, wherein the thermoplastic film B has adhesiveness to the columnar substrate A.

4. The method for manufacturing a bonded body according to claim 1 or 2, wherein the width of the thermoplastic film B in a direction perpendicular to the circumferential direction of the columnar substrate A is 3 to 30 mm.

5. The method for manufacturing a bonded body according to claim 1 or 2, wherein the thickness of the thermoplastic film B is 10 μm or more and 3 mm or less.

6. The method for manufacturing a bonded body according to claim 1 or 2, wherein when the melting point of the thermoplastic film B or, when there is no melting point, the temperature obtained by adding 70 °C to the glass transition temperature is defined as X °C, and the resin temperature during molding of the resin C is defined as Y °C, the value obtained by subtracting X °C from Y °C is 100 to 250 °C.

7. The method for manufacturing a bonded body according to claim 1 or 2, wherein the thermoplastic film B is mainly composed of an amorphous thermoplastic resin.

8. The method for manufacturing a bonded body according to claim 7, wherein the amorphous thermoplastic resin is a resin having a heat of fusion of 15 J / g or less.

9. The method for manufacturing a bonded body according to claim 7, wherein the amorphous thermoplastic resin is at least one of a thermoplastic epoxy resin and a phenoxy resin.

10. The method for manufacturing a bonded body according to claim 1 or 2, wherein the thermoplastic film B is a thermoplastic resin having an epoxy equivalent of 1,600 g / eq. or more or containing no epoxy group.

11. The method for manufacturing a bonded body according to claim 1 or 2, wherein the columnar substrate A is a metal.

12. The method for manufacturing a bonded body according to claim 1 or 2, wherein the resin C is a thermoplastic resin.

13. The method for manufacturing a bonded body according to claim 1 or 2, wherein the thermoplastic film B is formed into a film by removing the solvent from a resin composition dissolved in a solvent.

14. A bonded body obtained by the method for manufacturing a bonded body according to claim 1, wherein when a leak test is performed by applying an air pressure of 0.1 MPaG to the sealed portion, the air leak amount is 1 ml / min or less.

15. A bonded body according to claim 14, wherein when the leak test is performed after heating the bonded body to 160° C., maintaining it at 160° C. for 1000 minutes, and then cooling it to 23° C., the air leak amount is 1 ml / min or less.

16. An electric and electronic component comprising at least one of the bonded body obtained by the method for manufacturing a bonded body according to claim 1 or the bonded body according to claim 14.

17. The electric and electronic component according to claim 16, which is a terminal block or an electric element.

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