Method for manufacturing metal terminal with film, method for manufacturing connector terminal, connector terminal, electrical / electronic component, and method for evaluating connector terminal

Abstract

Disclosed is a method for manufacturing a metal terminal with a film, the method including: disposing one or a plurality of metal terminals between thermoplastic films; and heating, melting and solidifying the thermoplastic films so as to join at least a part of each of the metal terminals and the thermoplastic films.

Description

Manufacturing method for metal terminal with film, manufacturing method for connector terminal, connector terminal, electrical / electronic component, and method for evaluating connector terminal

[0001] The present invention relates to a method for manufacturing a connector terminal in which a thermoplastic resin and a metal terminal, which are different materials, are firmly joined, and to related techniques.

[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] Connector terminals are an example of a product that uses parts requiring multi-materialization. Connector terminals are configured with at least an insulator and an electrode body inside an outer container. Metal terminals often have a positive electrode body and a negative electrode body extending from a through-hole 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 sealing parts.

[0004] For example, a technique for sealing the periphery of a metal terminal, which is an electrode body, 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 is known in which a primer layer is formed by applying an in-situ polymerizing composition to an electrode body and polymerizing it, and then a sealing portion is formed (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 passed through to form a terminal adhesive layer, and then a sealing member is formed (Patent Document 2, etc.). Furthermore, a method is also being investigated in which the surface of a metal terminal is roughened and then sealed with a resin material by insert molding. 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] Therefore, the present invention relates to a method for manufacturing a connector terminal that can be joined in a short joining process time, can firmly join dissimilar materials, and has excellent leak resistance, and to related techniques.

[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] <Method for manufacturing a metal terminal with a film> [1] A method for manufacturing a metal terminal with a film, comprising placing one or more metal terminals between thermoplastic films, and heating, melting, and solidifying the thermoplastic films to bond at least a portion of the metal terminal to the thermoplastic films. [2] A method for manufacturing a metal terminal with a film according to [1], comprising placing the one or more metal terminals between a first thermoplastic film and a second thermoplastic film, and pressing the first thermoplastic film and the second thermoplastic film against the heated metal terminal to perform the heat-melting. [3] A method for manufacturing a metal terminal with a film according to [1], comprising placing the one or more metal terminals between an overlapping portion formed by folding back a single thermoplastic film, and pressing the overlapping portion against the heated metal terminal to perform the heat-melting. [4] A method for manufacturing a metal terminal with a film according to any one of [1] to [3], wherein the heated metal terminal is heated to a temperature of 100 to 250°C. [5] A method for manufacturing a film-attached metal terminal according to any one of [1] to [4], wherein the thermoplastic film has tackiness to the metal terminal. [6] A method for manufacturing a film-attached metal terminal according to any one of [1] to [5], wherein the metal terminal has a square or round pin shape with a pin diameter of 1 to 3 mm. [7] A method for manufacturing a film-attached metal terminal according to any one of [1] to [6], wherein the thermoplastic film has a thickness of 10 μm to 3 mm. [8] A method for manufacturing a film-attached metal terminal according to any one of [1] to [7], wherein the heat-melting is performed by heating the thermoplastic film for 0.1 to 120 seconds. [9] A method for manufacturing a film-attached metal terminal according to any one of [1] to [8], wherein the thermoplastic film is mainly composed of an amorphous thermoplastic resin.

[10] A method for manufacturing a film-attached metal terminal according to any one of [1] to [9], wherein the thermoplastic film is at least one of a thermoplastic epoxy resin and a phenoxy resin.

[11] The method for producing a metal terminal with a film according to any one of [1] to

[10] , wherein the thermoplastic film is mainly composed of an amorphous thermoplastic resin having an epoxy equivalent of 1,600 g / eq. or more and a heat of fusion of 15 J / g or less.

[12] The method for producing a metal terminal with a film according to any one of [1] to

[11] , wherein the thermoplastic film is formed by removing the solvent from a resin composition dissolved in a solvent.

[0010] <Method for manufacturing connector terminal>

[13] A method for manufacturing a connector terminal, comprising: placing a film-coated metal terminal obtained by the method for manufacturing a film-coated metal terminal according to any one of [1] to

[12] as an insert part into a cavity of an insert molding die; injecting and filling a thermoplastic resin into the cavity; and joining at least a film portion of the film-coated metal terminal and the thermoplastic resin by insert molding to seal the film portion.

[14] A method for manufacturing a connector terminal according to

[13] , wherein the melting point of the thermoplastic film, or a temperature obtained by adding 70°C to the glass transition temperature if there is no melting point, is X°C, and the resin temperature during insert molding of the thermoplastic resin is Y°C, and the value obtained by subtracting X°C from Y°C is 100 to 250°C.

[0011] <Connector terminal>

[15] A connector terminal obtained by the manufacturing method of

[13] or

[14] , in which an air leakage rate of 1 ml / min or less is observed when a leak test is conducted by applying an air pressure of 0.1 MPaG to the sealed portion.

[16] The connector terminal according to

[15] , in which an air leakage rate of 1 ml / min or less is observed when the connector terminal is heated to 160°C, maintained at 160°C for 1000 minutes, and then cooled to 23°C and the leak test is conducted.

[0012] <Electronic Components>

[17] An electric / electronic component comprising the connector terminal of

[15] or

[16] .

[18] The electric / electronic component of

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

[0013] <Method for evaluating connector terminals>

[19] A method for evaluating connector terminals, comprising confirming that an air leakage rate is 1 ml / min or less when a leak test is performed by applying an air pressure of 0.1 MPaG to the sealed portion of the connector terminal obtained by the manufacturing method of

[13] or

[14] .

[20] The method for evaluating connector terminals of

[19] , in which the connector terminal is heated to 160°C, maintained at 160°C for 1000 minutes, cooled to 23°C, and then the leak test is performed, and the air leakage rate is 1 ml / min or less.

[0014] According to the present invention, it is possible to provide a method for manufacturing a connector terminal, which requires a short joining process time, firmly joins dissimilar materials, and has excellent leak resistance, and related techniques.

[0015] Fig. 2 is a cross-sectional view illustrating a process for manufacturing a metal terminal with a film. Fig. 3 is a cross-sectional view illustrating a metal terminal 4 with a film obtained in the process of Fig. 1. Fig. 4 is an explanatory view of a comb-shaped metal terminal which is one embodiment of a metal terminal. Fig. 5 is a cross-sectional view illustrating a process for manufacturing a connector terminal. Fig. 6 is a cross-sectional view consisting of a cut surface parallel to the length direction of the connector terminal. Fig. 7 is a schematic view of a connector terminal for illustrating an example.

[0016] Embodiments of the present invention are 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 (e.g., thermosetting resin or 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 possessing adhesive strength sufficient to join two objects together. In this specification, the term "bonding process time" refers to the time from the start point (when the metal terminal and thermoplastic film constituting a film-coated metal terminal come into contact) to the end point (when the connector terminal is completed). For example, this includes the time required for placing the film on the metal terminal and for joining and sealing the thermoplastic 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 a numerical range can be combined arbitrarily.

[0017] <Method for manufacturing a metal terminal with a film> In one embodiment, a method for manufacturing a metal terminal with a film includes placing a metal terminal between thermoplastic films, heating the thermoplastic films to melt and solidify them, and joining at least a portion of the metal terminal to the thermoplastic films.

[0018] The method of placing the metal terminal between thermoplastic films and heating and melting the thermoplastic films may be a method of placing the metal terminal between a first thermoplastic film and a second thermoplastic film and pressing the first thermoplastic film and the second thermoplastic film against the heated metal terminal to perform the heating and melting, or a method of placing the metal terminal between overlapping portions of a single thermoplastic film folded back and overlapping, and sandwiching and pressing the heated metal terminal between the thermoplastic films to perform the heating and melting. The thermoplastic film may also be heated and melted by heat transfer from a heated mold. The two heating methods may also be used in combination.

[0019] An example of the embodiment will be described with reference to Figures 1 and 2. Figure 1 is a cross-sectional view illustrating the process for manufacturing a metal terminal with a film. Figure 2 is a cross-sectional view illustrating a metal terminal with a film 4 obtained in the process of Figure 1.

[0020] As shown in FIG. 1(A), a film bonding mold 1 may be opened, and two metal terminals 2 may be placed between a first thermoplastic film 3A and a second thermoplastic film 3B within the mold 1. The number of metal terminals is not particularly limited. The film bonding mold 1 may be composed of a first mold 1A and a second mold 1B. After placing the metal terminals 2 within the mold 1, as shown in FIG. 1(B), the mold 1 may be closed, and the first thermoplastic film 3A and the second thermoplastic film 3B may be pressed against each other to sandwich the heated metal terminal 2. Heat transfer from the metal terminal 2 may heat and melt the first thermoplastic film 3A and the second thermoplastic film 3B. The film may then be solidified by cooling. Cooling may be achieved by simply opening the mold 1, or by subsequently pressing the film-coated metal terminal 4 against a cooling mold or the like.

[0021] In one embodiment, the film-attached metal terminal 4 obtained by the process of Figures 1(A) and 1(B) may be a film-attached metal terminal 4 that includes a plurality of metal terminals 2, a first thermoplastic film 3A, and a second thermoplastic film 3B, as shown in Figure 2(A), and each of the metal terminals 2 is sandwiched between the first thermoplastic film 3A and the second thermoplastic film 3B and bonded to each of the first thermoplastic film 3A and the second thermoplastic film 3B.

[0022] In another embodiment, the film-attached metal terminal 4 obtained by the process of Figures 1(A) and 1(B) may be a film-attached metal terminal 4 as shown in Figure 2(B), which includes one metal terminal 2, a first thermoplastic film 3A, and a second thermoplastic film 3B, and in which the metal terminal 2 is sandwiched between the first thermoplastic film 3A and the second thermoplastic film 3B and bonded to each of the first thermoplastic film 3A and the second thermoplastic film 3B.

[0023] The film-coated metal terminal 4 obtained by the process of Figures 1(A) and 1(B) may have ears 5 formed by overlapping and joining the first thermoplastic film 3A and the second thermoplastic film 3B, without sandwiching the metal terminal 2 between them. In the embodiment of Figures 2(A) and 2(B), the metal terminal 2 has ears 5 on both ends, but may have an ear 5 on only one end.

[0024] The film-coated metal terminal 4 including one metal terminal 2 may be obtained by cutting off the tabs 5 of a film-coated metal terminal 4 including a plurality of metal terminals 2. Cutting off the tabs 5 may be performed during the manufacturing stage of the film-coated metal terminal, or may be performed when the film-coated metal terminal 4 is placed in the cavity of the insert molding die 8 during the manufacturing stage of the connector terminal described below.

[0025] Because the thermoplastic films 3A and 3B are thermoplastic, they are tightly bonded to the metal terminal 220 without any gaps. By heating, melting, and solidifying the thermoplastic films 3A and 3B before insert molding the thermoplastic resin 9 during the manufacture of the connector terminal, as described below, the metal terminal 2 and the thermoplastic films 3A and 3B can be more reliably bonded together. This improves the sealing performance of the connector terminal and further improves its leak resistance. By applying pressure to the surfaces of the thermoplastic films 3A and 3B during the heating and melting of the thermoplastic films 3A and 3B, the gap between the metal terminal 2 and the thermoplastic films 3A and 3B can be reduced.

[0026] [Heat Melting and Solidification] The metal terminal 2 may be heated before or after being placed between the first thermoplastic film 3A and the second thermoplastic film 3B. The method for heating the metal terminal 2 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.

[0027] The heating temperature may be determined taking into consideration the heat resistance temperature of the material of the metal terminal, and may be 100 to 250°C, 120 to 180°C, or 150 to 170°C.

[0028] The time for heat-melting the first thermoplastic film 3A and the second thermoplastic film 3B may be 0.1 to 120 seconds, 0.5 to 60 seconds, 1 to 30 seconds, or 3 to 20 seconds. By heat-melting at the above temperature for the above time, the thermoplastic films 3A and 3B are efficiently deformed and effectively wet and spread across the joining surface, resulting in a high joining strength.

[0029] Methods for solidifying the heated and melted thermoplastic films 3A and 3B include a method of allowing them to cool at room temperature or a method of allowing them to cool using a cooling device. "Room temperature" refers to a typical room temperature in the range of 5 to 30°C. Among these, the method of allowing them 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.

[0030] The metal terminal 2 may be a single metal terminal or multiple metal terminals. The metal is not particularly limited, and examples thereof include aluminum, iron, copper, magnesium, and titanium. 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, the terms copper, aluminum, magnesium, and titanium are used to include these elements and their alloys.

[0031] The metal terminal may have a square or round pin shape with a pin diameter of 0.2 to 10 mm. The shape of the metal terminal is not particularly limited, and the cross-sectional shape of the metal terminal may be square, rectangular, rounded square, rounded rectangular, circular, or elliptical. The pin diameter refers to the length of one side for a square pin, the length of the long and short sides for a rectangle, the diameter for a circular pin, and the major and minor axes for an elliptical pin. The pin diameter may be 0.3 to 5 mm or 0.5 to 3 mm. When the cross-sectional shape is elliptical, the aspect ratio may be 1 to 10 or 1 to 2. As shown in FIG. 3 , the metal terminal may be a comb-shaped metal terminal 7 in which the plurality of metal terminals 2 are spaced apart and their base ends are connected together by a connecting portion 6.

[0032] The metal terminal may have a cylindrical shape with a threaded groove formed on the inner peripheral wall.

[0033] (Pretreatment) The surface of the metal terminal 2 is preferably pretreated to remove surface contaminants and / or to achieve 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 metal terminal 2 or roughening the surface. Specifically, when the metal terminal 2 is made of aluminum, copper, or iron, at least one treatment selected from the group consisting of degreasing, UV ozone treatment, blasting, polishing, plasma treatment, and etching is preferred. Only one type of pretreatment may be used, or two or more types may be used. These pretreatment methods can be known in the art.

[0034] The degreasing process is a method of removing dirt such as oil and grease from the surface of the metal terminal 2 by dissolving it with an organic solvent such as acetone or toluene.

[0035] 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.

[0036] 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.

[0037] Examples of the polishing treatment include buff polishing using an abrasive cloth, roll polishing using abrasive paper (sandpaper), and electrolytic polishing.

[0038] 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.

[0039] 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.

[0040] Laser treatment is a technique for improving the surface characteristics by rapidly heating and cooling only the surface of the metal terminal 2 by irradiating it with a laser, and is an effective method for roughening the surface. Any known laser treatment technique can be used.

[0041] 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.

[0042] 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.

[0043] [Thermoplastic films 3A, 3B] The thermoplastic films 3A, 3B are primarily composed of a thermoplastic resin. Furthermore, the thermoplastic films 3A, 3B preferably have adhesive properties to the metal terminal 2. The "primary component" refers to the component with the highest content among the resin components in the thermoplastic films 3A, 3B. The thermoplastic films 3A, 3B preferably contain 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 primarily composed of a thermoplastic resin molded into a thin film.

[0044] <<Y°C - X°C>> If the thermoplastic resin used for thermoplastic films 3A and 3B has a melting point, the melting point of thermoplastic films 3A and 3B is X°C. Alternatively, if the thermoplastic resin used for thermoplastic films 3A and 3B does not have a melting point, X°C is the temperature obtained by adding 70°C to the glass transition temperature, and Y°C is the resin temperature of thermoplastic resin 9 during molding. 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 Y°C - X°C is in the range of 0 to 300°C, thermoplastic films 3A and 3B efficiently melt due to the heat generated by thermoplastic resin 9 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.

[0045] <<Amorphous Thermoplastic Resin>> The thermoplastic films 3A and 3B preferably contain an amorphous thermoplastic resin as a primary component. 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. If 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.

[0046] The heat of fusion of the amorphous thermoplastic resin is 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 thermoplastic films 3A and 3B mainly composed of an amorphous thermoplastic resin with 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 films 3A and 3B do not flow out from between the metal terminal 2 and the thermoplastic resin 9, ensuring a stable thickness of the thermoplastic films 3A and 3B, and achieving a stable high bonding strength. In order to fully impart the properties of an amorphous thermoplastic resin to the thermoplastic films 3A and 3B, 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 films 3A and 3B.

[0047] 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 films 3A and 3B have as their main component an amorphous thermoplastic resin that 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 films 3A and 3B have as their main component an amorphous thermoplastic resin that is at least one of a thermoplastic epoxy resin and a phenoxy resin, and that has 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 films 3A and 3B. The thermoplastic films 3A and 3B preferably contain 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.

[0048] 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 metal terminal 2 and thermoplastic resin 9, and are expected to be able to join dissimilar materials with a stronger bonding strength than conventional crystalline hot melt adhesives.

[0049] In particular, from the viewpoint of storage stability, it is preferable that the thermoplastic films 3A and 3B have an epoxy equivalent of 1,600 g / eq. or more or are thermoplastic resins that do 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 films 3A and 3B 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.

[0050] <<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.

[0051] (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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] Physical Properties of Thermoplastic Epoxy Resin and Phenoxy Resin Thermoplastic epoxy resin and phenoxy resin 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 is the molecular weight in terms of standard polystyrene. A MW within this range provides a good balance of thermoplasticity and heat resistance, allowing efficient production of connector terminals (described below) through heat melting, and also enhancing their heat resistance. A MW of 10,000 or greater provides excellent heat resistance, while a MW of 500,000 or less provides low viscosity during heat melting and enhanced bonding strength. The connector terminal is a bonded assembly formed by bonding a metal terminal 2, a thermoplastic film 3, and a thermoplastic resin 9 in this order, hereinafter also referred to as a bonded assembly.

[0057] <<Components other than resin components in thermoplastic films 3A and 3B>> If necessary, thermoplastic films 3A and 3B may contain fillers or additives as components other than resin components, as long as the object of this embodiment is not impaired.

[0058] Examples of fillers include inorganic fillers and organic fillers (such as resin powder). 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 the thermoplastic films 3A and 3B contain a filler, the content of the filler in the total amount (100% by volume) of the thermoplastic films 3A and 3B 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 the thermoplastic films 3A and 3B by the apparent specific gravity of the filler. The content of the resin component in the total amount (100% by volume) of the thermoplastic films 3A and 3B 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.

[0059] 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 the thermoplastic films 3A and 3B 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 the thermoplastic films 3A and 3B 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.

[0060] <<Shape of Thermoplastic Films 3A, 3B>> Thermoplastic films 3A, 3B are sheet-like. The width of thermoplastic films 3A, 3B in a direction perpendicular to the circumferential direction of metal terminal 2 is preferably 3 to 30 mm. The width of thermoplastic films 3A, 3B 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 thermoplastic films 3A, 3B is more preferably 25 mm or less, and even more preferably 20 mm or less. From the same viewpoint, the width of thermoplastic films 3A, 3B is more preferably 4 mm or more, and even more preferably 5 mm or more.

[0061] The thickness of the thermoplastic films 3A, 3B before being bonded to the metal terminal 2 is preferably 10 μm to 3 mm. From the viewpoint of obtaining a firmly bonded bonded body in a short bonding process time, the thickness of the thermoplastic films 3A, 3B 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 films 3A, 3B 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 films 3A, 3B is 10 μm to 3 mm, they can efficiently spread over the bonding surface with the metal terminal 2 by heating or the like, resulting in high bonding strength and leak resistance. The thickness after being bonded to the metal terminal 2 may be 10 to 200 μm or may be 30 to 50 μm.

[0062] The thermoplastic films 3A and 3B may be a single layer or a laminate consisting of multiple layers, but from the standpoint of ease of production and improved bonding strength, it is preferable that the thermoplastic films 3A and 3B be a single layer.

[0063] The thermoplastic films 3A and 3B may also have tackiness to the extent that it does not impair leak resistance. Tackiness can be imparted by mixing a tackifier resin into the thermoplastic resin constituting the thermoplastic films 3A and 3B, or by applying an adhesive to the surfaces of the thermoplastic films 3A and 3B. Tackiness can be imparted to one or both sides, but applying it to one side is preferable because it allows only the surface in contact with the metal terminal 2 to have tackiness and reduces the likelihood of the adhesive surface being exposed to the outside. The adhesive may be applied to the entire surface or to a partial area, such as in a striped, dotted, grid, or tiled pattern (a shape consisting of multiple squares arranged with gaps between them). A small application area is preferable because the adhesive is less likely to protrude and be exposed from the edge surfaces of the thermoplastic films 3A and 3B, reducing the likelihood of a decrease in leak resistance. Tackiness may also be imparted in a small amount, sufficient to provide a non-slip surface. That is, when the thermoplastic films 3A, 3B are wrapped around the metal terminal 2, the thermoplastic films 3A, 3B do not need to stick to the metal terminal 2, but may have a degree of resistance (less slippage) when a force in the shearing direction is applied. Lower tackiness is preferred because it tends to increase adhesive strength and provide excellent leak resistance.

[0064] <<Method for Producing Thermoplastic Films 3A and 3B>> The method for producing the thermoplastic films 3A and 3B is not particularly limited. The method for producing the thermoplastic films 3A and 3B may include a step of removing the solvent from a resin composition dissolved in the 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. The obtained resin composition is then applied to a release film or the like, cured and dried, and optionally pressurized to obtain the thermoplastic films 3A and 3B. The polymerization reaction may be carried out after application to the release film, after the solvent is removed to obtain a film shape, or a combination of these.

[0065] <Method for Manufacturing Connector Terminal> In one embodiment, a method for manufacturing a connector terminal includes placing the film-coated metal terminal 4 obtained by the above method as an insert part into a cavity of an insert molding die, injecting a thermoplastic resin into the cavity, and joining at least the film portion of the film-coated metal terminal to the thermoplastic resin by insert molding to seal the film portion. The film-coated metal terminal 4, which is an insert part, may be manufactured in a series of processes by the connector terminal manufacturer or by another manufacturer.

[0066] [Insert Molding] A conventionally known method can be used for insert molding. An example of an embodiment will be described with reference to Fig. 4. Fig. 4 is a cross-sectional view illustrating a process for manufacturing a connector terminal by insert molding using the film-coated metal terminal obtained by the above method as an insert part.

[0067] As shown in FIG. 4(A), the film-coated metal terminal 4 obtained by the above method is placed in the cavity of an insert molding die 8, and thermoplastic resin is filled by heating and pressurization. Specifically, after the film-coated metal terminal 4, which includes one metal terminal 2 in one embodiment, is placed in the cavity of the insert molding die 8, thermoplastic resin 9a is injected and filled into the cavity through a resin injection port provided in the insert molding die 8. At this time, insert molding is performed so that the thermoplastic resin 9 covers at least a portion, preferably all, of the thermoplastic films 3A and 3B of the film-coated metal terminal 4 and bonds them, and the film-coated metal terminal 4 is then removed from the insert molding die 8. The number of metal terminals 2 included in the film-coated metal terminal 4 is not limited and may be one or more. By undergoing the process shown in FIG. 4(A), a connector terminal 10 is manufactured in which a metal terminal 220 is sealed with thermoplastic resin 9 via the thermoplastic films 3A and 3B, as shown in FIG. 4(B).

[0068] By providing the thermoplastic films 3A and 3B between the metal terminal 4 and the thermoplastic resin 9 serving as a sealant, the metal terminal 2 and the thermoplastic resin 9 are firmly bonded together. The method of the present disclosure, in which the thermoplastic films 3A and 3B are bonded to the metal terminal 2 by heating, melting, and solidifying the thermoplastic films 3A and 3B, is an effective operation for shortening the bonding process compared to applying a liquid bonding agent or the like. Furthermore, by using the thermoplastic films 3A and 3B with a uniform thickness, uneven areas such as uncoated areas and dripping are prevented compared to applying a liquid bonding agent or the like, and excellent leak resistance can be achieved.

[0069] 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 the thermoplastic resin 9 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 connector terminal.

[0070] The detailed reasons for the effects of the present invention are considered as follows. By providing a thermoplastic resin that has undergone a chemical reaction, such as polymerization, between the metal terminal 2 and the thermoplastic resin 9, 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. Thermoplastic resins retain their thermoplasticity even at high temperatures, allowing stress relief. Stress can be reset after each thermal cycle, preventing peeling. Therefore, the use of thermoplastic films 3A and 3B allows for plastic deformation and effective stress relief, resulting in connector terminals that are less likely to peel during thermal cycles and have excellent leak resistance. Furthermore, the softening of the thermoplastic resin 9 when exposed to high temperatures further reduces stress, resulting in excellent leak resistance. As a preferred embodiment, when thermoplastic films 3A and 3B are used, the film is less likely to undergo a sudden viscosity drop upon heating, allowing the connector terminals to maintain their shape and leak resistance when exposed to high temperatures. As a preferred embodiment, by using thermoplastic films 3A and 3B primarily composed of an amorphous thermoplastic resin with an epoxy equivalent of 1,600 or more and a heat of fusion of 15 J / g or less, the sudden viscosity drop seen with conventional hot melt adhesives does not occur upon 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 when heated and melted, thermoplastic films 3A and 3B do not flow out of mold 1, ensuring a stable thickness and consistently achieving high adhesive strength.

[0071] [Thermoplastic Resin 9] In this embodiment, the thermoplastic resin 9 is used as a sealing material. The thermoplastic resin 9 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, the thermoplastic resin 9 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 ethers and modified products thereof, polyphenylene sulfide, polyoxymethylene, polyarylate, polyether ketone, polyether ether ketone, polyether ketone ketone, thermoplastic epoxy, and fiber-reinforced materials thereof. The thermosetting resin may be, for example, one or more selected from epoxy resins, vinyl ester resins, phenolic resins, urethane resins, etc. From the viewpoints of heat resistance, bonding strength, cost, ease of molding, etc., it is preferable that the thermosetting resin be at least one selected from polycarbonate, glass fiber reinforced polyamide, glass fiber reinforced polybutylene terephthalate, and glass fiber reinforced polyphenylene sulfide.

[0072] The molding temperature (resin temperature) of the thermoplastic resin 9 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 films 3A and 3B are efficiently deformed and melted by heating, and effectively wet and spread over the bonding surfaces, resulting in a high bonding strength.

[0073] There are no particular limitations on the combination of the material of the metal terminal 2 and the thermoplastic resin 9. In the connector terminal of this embodiment, there are no particular limitations on the thickness of the thermoplastic resin 9 (sealing material), and it can be set appropriately according to the application within a range that provides excellent bonding strength and leak resistance.

[0074] <Connector Terminal> An example of a connector terminal manufactured by the connector terminal 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 connector terminal. As shown in Fig. 5 , a connector terminal 10 is formed by sealing a metal terminal 2 with thermoplastic resin 9 via thermoplastic films 3A and 3B. The thermoplastic films 3A and 3B provide excellent bonding strength and adhesion between the metal terminal 2 and the thermoplastic resin 9. This prevents air from entering or exiting the sealed portion surrounded by the solid line, thereby achieving leak resistance.

[0075] The connector terminal of this embodiment is formed by joining dissimilar materials, but exhibits excellent joint strength. The joint strength is affected by many factors, including the strength of the interfacial interactions between the thermoplastic films 3A, 3B and the metal terminal 2, and between the thermoplastic films 3A, 3B and the thermoplastic resin 9, as well as the thickness of the thermoplastic films 3A, 3B, the molecular weight and chemical structure, mechanical properties, and viscoelastic properties of the polymers that make up the thermoplastic films 3A, 3B. Therefore, the details of the mechanism by which the joined body of this embodiment exhibits excellent joint strength and leak resistance are not clear.

[0076] In a more preferred embodiment of the connector terminal, the thermoplastic films 3A, 3B are 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 strength of the amorphous thermoplastic resin and the formation of chemical bonds and intermolecular forces, such as hydrogen bonds and van der Waals forces, at the interfaces between the thermoplastic films 3A, 3B and the metal terminal 2, and between the thermoplastic films 3A, 3B and the thermoplastic resin 9, if hydroxyl groups are present in the resin.

[0077] However, in the connector terminal of this embodiment, the state or characteristics of the interface between the thermoplastic films 3A, 3B and the metal terminal 2, and the interface between the thermoplastic films 3A, 3B and the thermoplastic resin 9 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 films 3A, 3B.

[0078] 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 connector terminal, the air leakage rate is preferably 1 mL / min or less. The "G" in the pressure unit MPa indicates gauge pressure. Furthermore, the connector terminal of this embodiment can effectively relieve stress during thermal cycling. Therefore, in an even more preferred embodiment, for example, the connector terminal is heated to 160°C, maintained at that temperature for 1,000 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 connector terminal 10 of this embodiment has a strong bond between the metal terminal 2 and the thermoplastic resin 9, is resistant to peeling during thermal cycling, and has excellent leak resistance, making it suitable for applications where these characteristics can be utilized. For example, an electrical or electronic component including the connector terminal of this embodiment can be provided. More specifically, as shown in Figure 5, it is possible to provide terminal blocks, bus bars, electrical elements, etc. for automobiles and electrical and electronic components that are equipped with connector terminals 10 of this embodiment, in which the entire thermoplastic films 3A, 3B on the metal terminals 2 are sealed by covering them with thermoplastic resin 9.

[0079] Hereinafter, the present embodiment will be specifically described with reference to examples and comparative examples, but the present embodiment is not limited to these.

[0080] The connector terminal of this embodiment is a joined body in which a thermoplastic resin 9 is joined by insert molding to at least the thermoplastic film 3 of a film-attached metal terminal in which a metal terminal 2 and a thermoplastic film 3 are joined. In the examples and comparative examples, joined bodies were produced by joining the metal terminal 2, the thermoplastic film 3 (example) or the bonding agent (comparative example), and the thermoplastic resin 9 in this order. Hereinafter, the layer consisting of the thermoplastic film 3 or the bonding agent will also be referred to as the intermediate layer. In the examples and comparative examples, the following materials were used. <Metal terminal 2> C1100 (tough pitch copper with a pin diameter of 1 mm) with a width of 1 mm, a thickness of 1 mm, and a length of 64.9 mm <Thermoplastic film 3> (Film 3-1) produced in Example 1 to (Film 3-9) produced in Example 9 <Bonding agent> (Bonding agent Q-1) produced in Comparative Example 1 to (Bonding agent Q-4) produced in Comparative Example 4 <Thermoplastic resin 9> Polyphenylene sulfide (containing 30% by mass of GF)

[0081] <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.)). Thermosetting resins that do not melt 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

[0082] (Heat of Fusion, Melting Point, and Glass Transition Temperature) 2 to 10 mg of each of the 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.

[0083] (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.

[0084] <Y-X (°C)> The melting points of the thermoplastic film 3 and the bonding agent were set to X°C, and the resin temperature during injection molding of the thermoplastic resin 9 was set to Y°C, and the value (Y°C-X°C) was calculated by subtracting X°C from Y°C.

[0085] Example 1 (Film 3-1) 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 mass. The resin composition was applied to a release-treated polyethylene terephthalate film (100 μm thick) and then heated at 160°C for 2 hours to remove the solvent, yielding Film 3 (3-1 in Example 1) with a solids content of 100% by mass, a length of 32 to 33 mm, and the thickness and width shown in Table 1-1. (Step 1a) After the metal terminal 2 was sandwiched between heating dies (not shown) and heated to 160°C, as shown in FIG. 1(A), the film bonding die 1 was opened, and two metal terminals 2 were placed between two thermoplastic films 3-1 within the die 1 at 20°C. As shown in FIG. 1(B), the die 1 was closed for 3 seconds, and the thermoplastic film 3-1 was heated and melted by heat transfer from the metal terminals 2. The film was then removed from the die and cooled at room temperature to solidify the film, yielding a film-attached metal terminal 4 (4-1 in Example 1) including the metal terminals. The film-attached metal terminal 4-1 included two metal terminals 2 and had a non-bonded portion where the thermoplastic film 3 was not bonded to the metal terminals 2. (Step 2) Using an injection molding machine (manufactured by Toyo Machinery & Metal Co., Ltd., model name "Si-100-6s") and a molding die, a thermoplastic resin 9 was insert molded and bonded to the thermoplastic film 3-1 portion of the film-attached metal terminal 4-1, thereby obtaining a connector terminal 10 (10-1 in Example 1) shown in Figure 6 (6-2). The insert molding conditions were an injection molding temperature (resin temperature) of 300 ° C, a mold temperature of 135 ° C, an injection speed of 15 mm / sec, an injection pressure of 130 MPa, a dwell pressure of 70 MPa, a dwell time of 4 seconds, and a cooling time of 30 seconds.

[0086] [Example 2] (Film 3-2) Film 3-2 was 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 1-1. (Step 1a and Step 2) Step 1a and Step 2 were performed in the same manner as in Example 1, except that Film 3-2 was used, to obtain a joint 10 (10-2 in Example 2) which is a connector terminal.

[0087] [Example 3] (Film 3-3) Film 3-3 was 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. (Step 1a and Step 2) Step 1a and Step 2 were performed in the same manner as in Example 1, except that the above-mentioned films were used, to obtain a joint 10 (10-3 in Example 3) which is a connector terminal.

[0088] Example 4 (Film 3-4) 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 2 hours to remove the solvent, yielding Film 3-4 with a solids content of 100% by mass, a length of 33 mm, and the thickness and width shown in Table 1-1. (Steps 1a and 2) Steps 1a and 2 were performed in the same manner as in Example 1, except that Film 3-4 was used, to obtain a connector terminal assembly 10 (10-4 in Example 4).

[0089] [Example 5] (Film 3-5) Film 3-5 was obtained in the same manner as in Example 4, except that the width of the film was 10 mm. (Step 1a and Step 2) Step 1a and Step 2 were performed in the same manner as in Example 1, except that Film 3-5 was used, to obtain a joint 10 (10-5 in Example 5) which is a connector terminal.

[0090] [Example 6] (Film 3-6) Film 3-6 was obtained in the same manner as in Example 4, except that 5% by mass (solids equivalent) of a tackifier resin (Tamanol 803L, manufactured by Arakawa Chemical Industries, Ltd.) was added. (Step 1b) After the metal terminal 2 was sandwiched between heating molds (not shown) and heated to 160°C, as shown in FIG. 1(A), the film bonding mold 1 was opened, and two metal terminals 2 were placed between two thermoplastic films 3-1 within the mold 1 at 20°C. As shown in FIG. 1(B), the mold 1 was closed for 3 seconds, and the thermoplastic film 3-6 was heated and melted by heat transfer from the metal terminals 2. The film was then removed from the mold and cooled at room temperature to solidify, resulting in a film-attached metal terminal 4 containing two metal terminals. Next, the tab 5 between the two metal terminals was cut to obtain two film-attached metal terminals 4 (4-6 in Example 6). As shown in Figure 6 (6-1), the metal terminal 4-6 includes one metal terminal and has a non-bonded portion a where the thermoplastic film 3 is not bonded to the metal terminal 2. (Step 2) Step 2 was carried out in the same manner as in Example 1 except that two film-attached metal terminals 4-6 were used, to obtain a bonded body 10 (10-6 in Example 6) which is a connector terminal.

[0091] [Example 7] (Film 3-7) Film 3-7 was obtained in the same manner as in the production of Film 3-4 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. (Step 1b and Step 2) Step 1b and Step 2 were performed in the same manner as in Example 6, except that Film 3-7 was used, to obtain a joint 10 (10-7 in Example 7) which is a connector terminal.

[0092] Example 8 (Film P-8) A solid (pellet-shaped) portion of PhenoToto (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 (100 μm thick), 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 3-8, which had 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 1a and 2) Steps 1a and 2 were performed in the same manner as in Example 1, except that Film 3-8 was used, to obtain a connector terminal assembly 10 (10-8 in Example 8).

[0093] [Example 9] (Film 3-9) Film 3-9 was obtained in the same manner as in Example 1. (Step 1c) As shown in FIG. 1(A), a film bonding mold 1 was opened, and two metal terminals 2 were placed between two thermoplastic films 3-9 within the mold 1, which had been heated to 160°C. Then, as shown in FIG. 1(B), mold 1 was closed for 3 seconds, and the thermoplastic film 3-1 was heated and melted by heat transfer from the mold. The film was then removed from the mold and cooled at room temperature to solidify, yielding a film-attached metal terminal 4 (4-9 in Example 9) including a metal terminal. The film-attached metal terminal 4-9 included two metal terminals 2 and had a non-bonded portion where the thermoplastic film 3 was not bonded to the metal terminal 2. (Step 2) A connector terminal assembly 10 (10-9 in Example 9) was obtained in the same manner as in Example 1, except that the film-attached metal terminal 4-9 was used.

[0094] [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. 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 thermosetting epoxy resin solution (bonding agent Q-1) with a solids content of 20% by mass. (Step 1d) The bonding agent Q-1 was applied to two metal terminals 2 and heated to 160 ° C. for 30 minutes to harden the bonding agent. Thereafter, it was cooled to room temperature, and an intermediate layer made of adhesive Q-1 was formed. As in Example 1, a non-adhered portion of the adhesive was provided on the metal terminal 2. The width of the intermediate layer is as shown in Table 2. (Step 2) As in Step 2 of Example 1, a bonded body of the metal terminal 2 and the thermoplastic resin 9 was obtained by insert molding and bonding the thermoplastic resin 9.

[0095] [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 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 and heat-set the film, thereby obtaining adhesive Q-2, which is a film with a solid content of 100% by mass, a length of 33 mm, and the thickness and width shown in Table 2. (Step 1a and Step 2) A bonded body was obtained by bonding a metal terminal 2, a film of adhesive Q-2, and a thermoplastic resin 9 in this order in the same manner as in Example 1, except that film Q-2 was used instead of film 3-1.

[0096] [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 1d and 2) In step 1d, the bonding agent Q-3 was applied to the metal terminal 2 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 the metal terminal 2 and the thermoplastic resin 9.

[0097] [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 (manufactured by Mitsubishi Chemical Corporation, bisphenol A-type epoxy resin, weight average molecular weight approximately 10,000), 0.95 equivalents (238 g) of PG-100 (manufactured by Osaka Gas Chemicals Co., Ltd., fluorene skeleton epoxy resin), 1.0 equivalent (125 g) of bisphenol S, 2 g of triphenylphosphine, and 1,000 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 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. (Step 1d and Step 2) In Step 1d (coating method), the bonding agent Q-4 was applied to the metal terminal 2, 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 carried out to obtain a bonded body of the metal terminal 2 and the thermoplastic resin 9.

[0098] <Workability> Workability was evaluated from the perspective of the bonding process time required for step 1 (step 1a, step 1b, step 1c, or step 1d) and handleability. The evaluation results are shown in Tables 1 and 2. In step 1a (Examples 1 to 5, 8, and Comparative Example 2) and step 1b (Examples 6 and 7), the thermoplastic film was heated and melted by heat transfer from the metal terminals to obtain a film-attached metal terminal including two metal terminals. In step 1b, after step 1a, the ear portion 5 between the two metal terminals was cut to obtain a film-attached metal terminal including one metal terminal. In step 1c (Example 9), the thermoplastic film was heated and melted by heat transfer from a mold to obtain a film-attached metal terminal including two metal terminals. In step 1d (Comparative Example 1 and Comparative Examples 3 and 4), an adhesive was applied to two metal terminals 2 to form an intermediate layer. When a film was used in step 1 (step 1a, step 1b, step 1c), the bonding process time was shorter than when a solution was used, and no dripping occurred, so the intermediate layer could be formed easily. <Evaluation criteria> A: Workability is "good". B: Workability is "poor" compared to A. C: Workability is extremely poor compared to A and is "poor".

[0099] <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 thermoplastic resin 9 and the hose H and the surrounding area to seal the joint. A plug coupler was attached to the end of the hose H without the assembly and connected to a compressor. After the entire assembly at the end of the hose to which the assembly was attached was submerged in water, air X was pumped into the hose H at an air pressure of 0.1 MPaG toward the assembly. The leaking air bubbles were visually observed. This procedure was performed on 12 assembly produced in each Example and Comparative Example, and the adhesion between the metal terminal 2 and the thermoplastic resin 9 was evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 1-1 to 1-3 and Table 2. If 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 in 10 out of 10 tests. B: No air bubbles were observed 8 to 9 times out of 10. C: No air bubbles were observed 5 to 7 times out of 10. D: No air bubbles were observed 0 to 4 times out of 10.

[0100] <Leakage Test After Thermal Cycles> The bonded bodies produced 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. The evaluation results are shown in Tables 1-1 to 1-3 and 2.

[0101] <Leakage test after heat resistance treatment> The bonded bodies produced in each of the examples and comparative examples were left to stand 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. The evaluation results are shown in Tables 1-1 to 1-3 and 2.

[0102]

[0103]

[0104]

[0105]

[0106] 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.

[0107] 1. Mold for film bonding 1A. First mold 1B. Second mold 2. Metal terminal 3. Thermoplastic film 3A. First thermoplastic film 3B. Second thermoplastic film 4. Metal terminal with film 5. Connection part 6. Linking part 7. Comb-shaped metal terminal 8. Mold for insert molding 9a. Thermoplastic resin (for injection) 9. Thermoplastic resin 10. Connector terminal

Claims

1. A method for manufacturing a metal terminal with a film, comprising arranging one or more metal terminals between thermoplastic films, heating and melting the thermoplastic films, and then solidifying them to bond at least a part of the metal terminals to the thermoplastic films.

2. The method for manufacturing a metal terminal with a film according to claim 1, wherein the one or more metal terminals are arranged between a first thermoplastic film and a second thermoplastic film, and the first thermoplastic film and the second thermoplastic film are pressed against the heated metal terminals to perform the heating and melting.

3. The method for manufacturing a metal terminal with a film according to claim 1, wherein the one or more metal terminals are arranged between overlapping portions formed by folding back and overlapping a single thermoplastic film, and the heated metal terminals are sandwiched and pressed by the thermoplastic film to perform the heating and melting.

4. The method for manufacturing a metal terminal with a film according to claim 2 or 3, wherein the temperature of the heated metal terminals is 100 - 250°C.

5. The method for manufacturing a metal terminal with a film according to any one of claims 1 - 3, wherein the thermoplastic film has tackiness to the metal terminals.

6. The method for manufacturing a metal terminal with a film according to any one of claims 1 - 3, wherein the metal terminals have a square pin shape or a round pin shape with a pin diameter of 1 - 3 mm.

7. The method for manufacturing a metal terminal with a film according to any one of claims 1 - 3, wherein the thickness of the thermoplastic film is 10 μm - 3 mm.

8. The method for manufacturing a metal terminal with a film according to any one of claims 1 - 3, wherein the heating and melting is performed by heating the thermoplastic film for 0.1 - 120 seconds.

9. The method for manufacturing a metal terminal with a film according to any one of claims 1 - 3, wherein the thermoplastic film is mainly composed of an amorphous thermoplastic resin.

10. The method for manufacturing a metal terminal with a film according to any one of claims 1 - 3, wherein the thermoplastic film is at least one of a thermoplastic epoxy resin and a phenoxy resin.

11. The method for manufacturing a metal terminal with a film according to any one of claims 1 - 3, wherein the thermoplastic film is mainly composed of an amorphous thermoplastic resin having an epoxy equivalent of 1,600 g / eq. or more and a heat of fusion of 15 J / g or less.

12. The method for manufacturing a metal terminal with a film according to any one of claims 1 to 3, wherein the thermoplastic film is formed by removing the solvent from a resin composition dissolved in a solvent to form a film.

13. A method for manufacturing a connector terminal, comprising: disposing the metal terminal with a film obtained by the method for manufacturing a metal terminal with a film according to claim 1 as an insert part in a cavity of an insert molding die, injecting and filling a thermoplastic resin into the cavity, and joining at least the film part of the metal terminal with a film and the thermoplastic resin by insert molding to seal the film part.

14. In the method for manufacturing a connector terminal according to claim 13, when the melting point of the thermoplastic film or, when the melting point does not exist, the temperature obtained by adding 70°C to the glass transition temperature is X°C, and the resin temperature during insert molding of the thermoplastic resin is Y°C, the value obtained by subtracting X°C from Y°C is 100 to 250°C.

15. A connector terminal obtained by the manufacturing method according to claim 13, 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.

16. A connector terminal according to claim 15, wherein when the connector terminal is heated to 160°C, held at 160°C for 1000 minutes, cooled to 23°C, and then the leak test is performed, the air leak amount is 1 ml / min or less.

17. An electric and electronic component comprising the connector terminal according to claim 15.

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

19. An evaluation method for a connector terminal, comprising: confirming that when a leak test is performed by applying an air pressure of 0.1 MPaG to the sealed portion of the connector terminal obtained by the manufacturing method according to claim 13, the air leak amount is 1 ml / min or less.

20. The evaluation method for a connector terminal according to claim 19, wherein when the connector terminal is heated to 160°C, held at 160°C for 1000 minutes, cooled to 23°C, and then the leak test is performed, the air leak amount is 1 ml / min or less.

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