Joint and method for manufacturing the same

Abstract

To provide a joint body of two members consisting of dissimilar materials which has high adhesion and high joint reliability, and a method for manufacturing the body.SOLUTION: A joint body 1 comprises: a first member 10 having a joint surface 11 in which a metal part is exposed; and a second member 20 which is joined to a joint surface 11 of the first member 10, and has a thermoplastic polymer and a basic substance, where the metal part has one or more kinds selected from nickel, tin, tin-nickel alloy, tin-bismuth alloy, tin-silver alloy and tin-copper alloy, and the surface of the metal part is processed by polyvalent carboxylic acid. A method for manufacturing a joint body 1 has: a surface treatment process in which solution having polyvalent carboxylic acid is brought in contact with a joint surface 11 in the first member 10 where the metal part is exposed, and dried, by which the surface of the metal part is processed by the polyvalent carboxylic acid; and a press process in which the second member 20 having a thermoplastic polymer and a basic substance which is laminated on the joint surface 11 of the first member 10, and pressed under heating.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a joined body in which two members made of different materials are joined and a method for manufacturing the same.

Background Art

[0002] For biosensors that measure biological information such as respiratory state and heart rate, steering sensors, seating sensors, etc. mounted on vehicles such as automobiles, followability to the movement of the subject and reduction of discomfort are required. For this reason, development of sensors using flexible materials such as elastomers has been progressing. For example, Patent Document 1 describes a capacitance sensor including an insulating layer having a thermoplastic elastomer and a mesh electrode made of a conductive polymer. Further, Patent Document 2 describes a sheet-like flexible electrode having a thermoplastic elastomer and a conductive material containing carbon black as an electrode used for a piezoelectric sensor, a capacitance sensor, etc.

[0003] A sensor is connected to an ECU (electronic control unit) etc. via wiring. If it is a metal electrode, it can be directly joined to the wiring by soldering etc. However, in the case of a flexible electrode using a polymer such as an elastomer, joining by soldering is difficult. For this reason, for example, it is necessary to embed a metal member in the flexible electrode and join it to the wiring using the contact therewith, or to caul the flexible electrode and the wiring with a metal member so that the contact is not impaired by deformation due to stress.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0005] When joining components made of dissimilar materials, such as polymers and metals, a significant difference in Young's modulus can lead to a decrease in adhesion and low reliability of the joint, as one component cannot deform in accordance with the deformation of the other. For example, when a metal component is embedded in a flexible electrode made of polymer, a gap is likely to form between the flexible electrode and the metal component when a load is applied and deformation occurs, resulting in increased contact resistance and reduced conductivity. Furthermore, repeated expansion and contraction of the flexible electrode may cause the metal component to peel off, potentially separating the flexible electrode and the metal component, thus reducing the reliability of the joint. Additionally, when a flexible electrode and wiring are joined by crimping with a metal component, the thickness of the joint increases. Moreover, as the polymer deteriorates with prolonged use, the contact area between the flexible electrode and the wiring decreases, potentially increasing contact resistance or causing damage to the joint.

[0006] This disclosure has been made in view of the above circumstances, and aims to provide a joint made of two members made of different materials that has high adhesion and high joint reliability, and a method for manufacturing the same. [Means for solving the problem]

[0007] (1) In order to solve the above problems, the joint of the present disclosure comprises a first member having a joint surface in which a metal part is exposed, and a second member joined to the joint surface of the first member and having a thermoplastic polymer and a basic substance, wherein the metal part has one or more selected from nickel, tin, tin-nickel alloy, tin-bismuth alloy, tin-silver alloy, and tin-copper alloy, and the surface of the metal part is treated with a polycarboxylic acid.

[0008] In the joint of this disclosure, a second member is joined to the joining surface of a first member. The metal portion of the joining surface of the first member has a predetermined metal, and its surface is treated with a polycarboxylic acid before being joined to the second member. When the surface of the metal portion is treated with a polycarboxylic acid, the oxide film (passivation film) present on the surface is removed, improving wettability. Furthermore, a polycarboxylic acid is an acid having two or more carboxyl groups (-COOH), and it dissociates and reacts in multiple stages. At a certain stage, when hydrogen dissociates from some of the carboxyl groups, the metal constituting the metal portion reacts with it. At this stage, carboxyl groups remain that react with basic substances or form hydrogen bonds. On the other hand, the second member has a basic substance. Therefore, when the second member is joined to the joining surface, it is thought that interactions such as hydrogen bonding occur between the remaining carboxyl groups and the basic substance, causing them to attract each other. In this way, when the surface of the metal portion of the joining surface is treated with a polycarboxylic acid, some of the carboxyl groups are stabilized by the reaction with the metal, and the remaining carboxyl groups interact with the basic substance, resulting in a large bonding force. As a result, a joint with high adhesion and high bonding reliability can be realized. Furthermore, the joint of this disclosure allows for easy electrical connection to wiring and the like by utilizing the metal portion of the first member.

[0009] Incidentally, Patent Document 3 describes a connecting structure in which a first solid member and a second solid member made of different materials are joined via an adhesive member containing a polymer. In the connecting structure described in Patent Document 3, the two solid members are joined by chemically bonding each to the polymer of the adhesive member. Paragraphs

[0111] ,

[0112] , and

[0120] of the same document describe pre-treating the surface of the solid members with acid, but acid treatment is merely an example of a treatment to make the surface of the solid members hydrophilic and facilitate the formation of chemical bonds with the polymer.

[0010] (2) In the above configuration, the polycarboxylic acid may be water-soluble. With this configuration, the polycarboxylic acid treatment can be carried out in an aqueous solution. This reduces the emission of VOCs (volatile organic compounds) and minimizes the impact on the environment.

[0011] (3) In any of the above configurations, the polycarboxylic acid may have 6 or fewer carbon atoms. Many polycarboxylic acids with 6 or fewer carbon atoms are readily soluble in water or alcohol. In particular, those with 4 or fewer carbon atoms are readily soluble in water, making it easy to adopt a configuration in which the polycarboxylic acid treatment in the above configuration (2) is carried out in an aqueous solution.

[0012] (4) In any of the above configurations, the polycarboxylic acid may be a configuration having at least one of succinic acid and citric acid. Succinic acid and citric acid are water-soluble, relatively non-corrosive to metals, have a low environmental impact, and offer excellent workability.

[0013] (5) In any of the above configurations, the basic substance may be one or more selected from basic compounds and substances having elements or functional groups capable of hydrogen bonding. Basic compounds and substances having elements or functional groups capable of hydrogen bonding are used in conductive materials, insulating materials, reinforcing materials, flame retardants, etc., which are compounded to impart desired properties to a second component. With this configuration, it is possible to induce interaction with the "reaction product of polycarboxylic acid and metal" produced by polycarboxylic acid treatment by utilizing additives compounded into the thermoplastic polymer.

[0014] (6) In the configuration of (5) above, the basic compound may include magnesium hydroxide, magnesium oxide, aluminum oxide, aluminum hydroxide, calcium oxide, calcium hydroxide, calcium carbonate, and silicon compounds, and the substance having elements or functional groups capable of hydrogen bonding may also include carbon black. The basic compound in this configuration is insulating. Therefore, if it is desired to impart insulating properties to the second member, a configuration having one or more of the basic compounds in this configuration is preferable. Carbon black also has basic functional groups such as chromene structures, or elements or functional groups capable of hydrogen bonding such as carbonyl groups, quinones, and metal salts. Therefore, if it is desired to impart conductivity to the second member, a configuration having carbon black is preferable.

[0015] (7) In any of the above configurations, the first member may be a conductive cloth. This configuration allows the first member to be flexible and thin, making it suitable for connecting the first member to an FPC (flexible printed circuit board) or the like.

[0016] (8) In any of the above configurations, the metal part may be a plated film. The plating process can be carried out using various metals and alloys such as nickel and tin. With this configuration, the metal part can be easily formed by utilizing the plating process.

[0017] (9) A method for manufacturing a joint according to the present disclosure is one embodiment of the method for manufacturing a joint according to the present disclosure, comprising: a surface treatment step of treating the surface of a metal part of a first member with a polycarboxylic acid by contacting the exposed joint surface of the first member, which has one or more metal parts selected from nickel, tin, tin-nickel alloy, tin-bismuth alloy, tin-silver alloy, and tin-copper alloy, with a solution having a polycarboxylic acid and drying it; and a pressing step of laminating a second member having a thermoplastic polymer and a basic substance onto the joint surface of the first member and pressing it under heating.

[0018] In the manufacturing method of the present disclosure, first, in a surface treatment step, the joint surface of the first member is treated with a polycarboxylic acid. Next, in a pressing step, the second member is laminated onto the treated joint surface and pressed under heating. In this way, the joint of the present disclosure can be easily manufactured according to the manufacturing method of the present disclosure.

[0019] (10) In the configuration of (9) above, the number of carbon atoms in the polycarboxylic acid may be 6 or less. As mentioned above, many polycarboxylic acids with 6 or fewer carbon atoms are readily soluble in water or alcohol. In particular, those with 4 or fewer carbon atoms are readily soluble in water, so an aqueous solution can be used as the solution containing the polycarboxylic acid. Using an aqueous solution can suppress the emission of VOCs and reduce the impact on the environment.

[0020] (11) In the configuration of (9) or (10) above, the polyvalent carboxylic acid may have at least one of succinic acid and citric acid. Succinic acid and citric acid are water-soluble and relatively difficult to corrode metals.

[0021] (12) In any of the configurations of (9) to (11) above, the basic substance may be composed of one or more selected from basic compounds and substances having an element or functional group capable of forming a hydrogen bond. According to this configuration, by using additives such as conductive materials, insulating materials, reinforcing materials, and flame retardant materials blended in the thermoplastic polymer, an interaction with the "reaction product of polyvalent carboxylic acid and metal" generated by polyvalent carboxylic acid treatment can be caused.

[0022] (13) In the configuration of (12) above, the basic compound may have magnesium hydroxide, magnesium oxide, aluminum oxide, aluminum hydroxide, calcium oxide, calcium hydroxide, calcium carbonate, a silicon compound, and the substance having an element or functional group capable of forming a hydrogen bond may have carbon black. The basic compound of this configuration has insulating properties. Therefore, when it is desired to impart insulating properties to the second member, a form having one or more of the basic compounds of this configuration is suitable. Also, carbon black has basic functional groups such as a chromene structure, and elements or functional groups capable of forming a hydrogen bond such as a carbonyl group, quinones, and metal salts. Therefore, when it is desired to impart conductivity to the second member, a form having carbon black is suitable.

[0023] (14) In any of the configurations of (9) to (13) above, the first member may be a conductive cloth. According to this configuration, the first member can be made flexible and thin, so it is suitable for a form in which the first member is connected to an FPC (flexible printed wiring board) or the like.

[0024] (15) In any of the configurations of (9) to (14) above, the metal part may be a plating film. According to this configuration, the metal part can be easily formed by using plating treatment.

Advantages of the Invention

[0025] According to the bonded body of the present disclosure, the surface of the metal part of the bonding surface of the first member is treated with a polyvalent carboxylic acid, so that the adhesion between the first member and the second member made of different materials can be enhanced, and the bonding reliability can be enhanced. According to the manufacturing method of the present disclosure, the bonded body of the present disclosure can be easily manufactured.

Brief Description of the Drawings

[0026] [Figure 1] It is a top view showing a connection form between the bonded body of the present disclosure and wiring.

Embodiments for Carrying Out the Invention

[0027] Hereinafter, embodiments of the bonded body of the present disclosure and its manufacturing method will be described. Note that the embodiments are not limited to the following forms, and various modified forms and improved forms that can be carried out by those skilled in the art can be implemented.

[0028] <Bonded body> The bonded body of the present disclosure is a bonded body including a first member having a bonding surface where a metal part is exposed, and a second member bonded to the bonding surface of the first member and having a thermoplastic polymer and a basic substance.

[0029] [First member] The first member is not particularly limited in terms of material, shape, size, etc., as long as it has a bonding surface where the metal part is exposed. The metal part may include one or more selected from nickel, tin, tin-nickel alloy, tin-bismuth alloy, tin-silver alloy, tin-copper alloy (hereinafter, may be referred to as "nickel-tin-based metal"). The metal part may be a plating film. Note that an oxide film may be formed on the surface depending on the type of metal. Although it is considered that the oxide film is removed by the polyvalent carboxylic acid treatment, the metal part may include the oxide film.

[0030] Examples of the first member include (a) a metal plate, metal sheet, wire mesh, etc., whose surface is at least made of nickel-tin metal; (b) a composite member in which a part including the joining surface is made of nickel-tin metal and the other part is made of other materials; and (c) a composite member in which the whole is made of nickel-tin metal and other materials. An example of the composite member in (c) is a conductive cloth made of nickel-tin metal and fibers. In the case where the entire first member is made of nickel-tin metal and other materials, such as a conductive cloth, it is sufficient that the metal part having nickel-tin metal is exposed at the joining surface. The conductive cloth may be either a cloth (including both woven and nonwoven cloths) formed from fibers such as polyethylene terephthalate (PET) with a metal plating on the surface, or a cloth formed from conductive fibers such as PET that have been metal-plated.

[0031] The surface of the metal part is treated with a polycarboxylic acid. Any polycarboxylic acid with two or more progenitor values ​​may be used, either individually or in combination of two or more. Examples of divalent carboxylic acids include aromatic dicarboxylic acids such as succinic acid, adipic acid, maleic acid, fumaric acid, and phthalic acid, as well as their isomers. Examples of trivalent carboxylic acids include aromatic tricarboxylic acids such as citric acid and trimellitic acid. The stepwise dissociation of hydrogen facilitates reactions with the metal part and interactions with basic substances in the second component. For example, the acid dissociation constants (pK) of the first and second stages... a A larger difference is desirable.

[0032] As described later, polycarboxylic acid treatment is carried out by bringing a solution containing a polycarboxylic acid into contact with the bonding surface. In this case, from the viewpoint of minimizing the impact on the environment by using water as the solvent, it is desirable that the polycarboxylic acid be water-soluble. Furthermore, it is desirable that the polycarboxylic acid has 6 or fewer carbon atoms, and moreover, 4 or fewer. In particular, from the viewpoint of being water-soluble and relatively less corrosive to metals, it is desirable to use at least one of succinic acid and citric acid.

[0033] [Second component] The thermoplastic polymer constituting the second component may be one type or a combination of two or more types. For example, it can be appropriately selected from resins or elastomers such as styrene-based, olefin-based, PVC-based, urethane-based, ester-based, and amide-based polymers. Among these, examples of styrene-based thermoplastic elastomers include styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), and styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS). Examples of olefin-based thermoplastic elastomers include low-density polyethylene (LDPE, LLDPE), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), ethylene-methacrylic acid copolymer (EMMA), and copolymers of ethylene and α-olefin (ethylene-octene copolymer). The thermoplastic polymer may or may not be crosslinked. For example, from the viewpoint of flexibility and a relatively low softening temperature, olefin-based resins or elastomers are preferred.

[0034] The basic substance constituting the second component can be appropriately selected according to the application, and one or more substances selected from basic compounds and substances having elements or functional groups capable of hydrogen bonding may be used. Examples of basic compounds include magnesium hydroxide, magnesium oxide, aluminum oxide, aluminum hydroxide, calcium oxide, calcium hydroxide, calcium carbonate, and silicon compounds. These compounds are suitable when it is desired to impart insulation to the second component because they have insulating properties. Examples of substances having elements or functional groups capable of hydrogen bonding include carbon black. Carbon black is suitable when it is desired to impart conductivity to the second component because it has conductivity.

[0035] The second component may contain, in addition to a thermoplastic polymer and a basic substance, lubricants, plasticizers, antioxidants, colorants, and the like. For example, incorporating a lubricant can reduce the shear force even when a load is applied to the second component by press molding. Therefore, when carbon black is incorporated as the basic substance, the structure becomes less prone to breakage. It is desirable to use one or more lubricants selected from fatty acids and fatty acid compounds.

[0036] The second member is joined to the joint surface of the first member. For example, if the joint surface of the first member is flat, the second member is laminated and joined to the joint surface. If the first member is wire mesh, conductive fabric, etc., and the joint surface is mesh-like (has gaps), a portion of the second member is embedded in the gaps of the joint surface, resulting in a greater joining force.

[0037] [Application] The applications of the joint of this disclosure are not particularly limited. For example, it can be used to connect flexible electrodes and wiring in piezoelectric sensors, capacitive sensors, actuators, etc., or to connect insulating layers (dielectric layers) and electrodes. Below, as an example of an application of the joint of this disclosure, a form in which the second member is embodied in the flexible electrode of a capacitive sensor is shown. Figure 1 shows a schematic top view of the connection configuration between the joint of this disclosure and wiring. In Figure 1, for the sake of explanation, the area corresponding to the joint surface is shown with hatching.

[0038] As shown in Figure 1, the joint 1 comprises a first member 10 and a second member 20. The first member 10 is made of conductive fabric and has a rectangular sheet shape. The conductive fabric is a woven fabric of conductive fibers, in which copper plating and nickel plating are applied in two layers from the inside to PET fibers. The rear lower surface of the first member 10 (the hatched area) is the joint surface 11 to be joined with the second member. The nickel coating on the outermost surface of the conductive fibers is exposed on the joint surface 11. The nickel coating is included in the concept of the metal part of this disclosure. The joint surface 11 is surface-treated with a citric acid aqueous solution before being joined with the second member 20. Wiring 30 is fixed to the front upper surface of the first member 10 with solder 31.

[0039] The second member 20 is made of a conductive sheet and has a strip shape extending in the left-right direction. The conductive sheet contains an olefin-based thermoplastic elastomer and carbon black. The right end of the second member 20 is joined to the joint surface 11 of the first member 10. A part of the second member 20 is embedded in the gap (mesh of the conductive fabric) of the joint surface 11. An insulating layer and a conductive sheet (not shown) are laminated in this order on the underside of the second member 20. In other words, the capacitance sensor is composed of the second member 20 (conductive sheet) / insulating layer / conductive sheet. The second member 20 functions as an electrode of the capacitance sensor.

[0040] In the bonded body 1, the surface of the metal part (nickel film) of the bonding surface 11 is pre-treated with citric acid, so the oxide film present on the surface of the metal part is removed, improving wettability. In addition, the reaction of the citric acid with the nickel of the metal part and the interaction with specific functional groups of carbon black increase the bonding strength. In other words, the adhesion between the first member 10 and the second member 20 is improved. On the other hand, the first member 10 and the wiring 30 are firmly fixed together with solder 31. Therefore, with the bonded body 1, the electrical connection between the flexible second member 20, which has a thermoplastic elastomer, and the wiring 30 can be easily and reliably made via the first member 10.

[0041] <Method for manufacturing a jointed body> The method for manufacturing a joined body according to this disclosure comprises a surface treatment step and a pressing step. Each step will be described below.

[0042] <Surface treatment process> This process involves treating the surface of a metal part of a first component with a polycarboxylic acid by contacting the exposed joint surface of the metal part, which has one or more metals selected from nickel, tin, tin-nickel alloy, tin-bismuth alloy, tin-silver alloy, and tin-copper alloy, with a solution containing a polycarboxylic acid (hereinafter sometimes referred to as "polycarboxylic acid solution") and drying it.

[0043] The metal parts of the first component and the joint surface are as described above. The solvent for the polycarboxylic acid solution can be appropriately selected from solvents such as water and ethanol, taking into consideration the solubility of the polycarboxylic acid. From the viewpoint of suppressing VOC emissions and minimizing environmental impact, it is desirable to use water. The concentration of the polycarboxylic acid solution can be appropriately determined taking into consideration the adhesion to the second component and the corrosiveness to the metal, for example, it can be about 0.001 to 1 mol / L.

[0044] The method of contact between the joint surface and the polycarboxylic acid solution is not particularly limited as long as the surface of the metal part can be treated with the polycarboxylic acid. For example, the polycarboxylic acid solution can be applied to the joint surface, or the part of the first member including the joint surface can be immersed in the polycarboxylic acid solution. In the latter case, the immersion time should be about 0.1 to 1 minute. After contact with the polycarboxylic acid solution, the surface should be dried to vaporize the solvent. The drying temperature and time should be determined appropriately depending on the solvent. After the polycarboxylic acid treatment, the joint surface may be cleaned with alcohol or the like to remove excess polycarboxylic acid and suppress metal corrosion. After cleaning, further drying is desirable.

[0045] <Pressing Process> This process involves laminating a second member, which has a thermoplastic polymer and a basic substance, onto the bonding surface of a first member treated with a polycarboxylic acid, and then pressing it under heat. The second member laminated onto the bonding surface may be in the state of a composition (precursor) for manufacturing the second member, or in the state after it has been manufactured as the second member. The pressing temperature should be appropriately determined considering the softening temperature of the thermoplastic polymer, productivity, etc. For example, when using an olefin-based elastomer, it is desirable to perform the process at a temperature of 150°C to 250°C. The pressing time should be set to the time required for bonding to be completed according to the pressing temperature. The pressing pressure is also not particularly limited as long as the first member and the second member can be bonded together. [Examples]

[0046] Next, the present disclosure will be described in more detail with reference to examples. In this example, a jointed sample was manufactured in which a conductive fabric as a first component and an elastomer sheet as a second component were joined together, and the adhesion between the two was evaluated.

[0047] <Manufacturing of bonded samples> [Example 1] As the first component, conductive fabric A was prepared. Conductive fabric A is a plain-woven fabric made of conductive fibers, each consisting of PET fibers with two layers of copper plating and nickel plating applied from the inside. Conductive fabric A is rectangular in shape, measuring 10 mm in length and 80 mm in width, and the nickel coating on the outermost surface of the conductive fibers is exposed on the surface. The prepared conductive fabric A was surface-treated as follows: First, conductive fabric A was immersed in a 0.5 mol / L citric acid aqueous solution for 1 minute. Next, conductive fabric A was removed from the citric acid aqueous solution and dried at 90°C for 2 hours. After that, conductive fabric A was washed with ethanol and dried again at 90°C for 0.5 hours.

[0048] The elastomer sheet for the second component was manufactured as follows: First, 100 parts by mass of olefin-based thermoplastic elastomer (ethylene-octene copolymer) was mixed with 20 parts by mass of conductive carbon black ("Ketjenblack® EC600JD" manufactured by Lion Specialty Chemicals Co., Ltd.), and the mixture was kneaded at 190°C in a kneader to produce an elastomer composition. Next, the elastomer composition was T-die extruded using a single-screw extruder to form a rectangular sheet with dimensions of 100 mm in length, 200 mm in width, and 0.2 mm in thickness.

[0049] The obtained conductive fabric A was laminated onto one side of the elastomer sheet and pressed in a press machine at a temperature of 200°C and a pressure of 1 MPa for 2 minutes. In this way, a bonded sample was manufactured in which conductive fabric A (first component) and elastomer sheet (second component) were joined. The manufactured bonded sample is referred to as the sample of Example 1.

[0050] [Example 2] Samples for Example 2 were prepared in the same manner as in Example 1, except that the citric acid aqueous solution was changed to a succinic acid aqueous solution (with the same concentration of 0.5 mol / L) in the surface treatment of the first component.

[0051] [Example 3] Sample for Example 3 was prepared in the same manner as in Example 1, except that the citric acid aqueous solution was changed to an adipic acid ethanol solution (with the same concentration of 0.5 mol / L) in the surface treatment of the first component.

[0052] [Example 4] A sample of Example 4 was manufactured in the same manner as in Example 1, except that the conductive fabric A of the first component was changed to conductive fabric B. Conductive fabric B is a woven fabric in which conductive fibers, each having a single layer of tin plating applied to PET fibers, are plain woven. The tin coating on the outermost surface of the conductive fibers is exposed on the surface of conductive fabric B.

[0053] [Example 5] In the production of the elastomer sheet for the second component, the sample for Example 5 was prepared in the same manner as in Example 1, except that the conductive carbon black blended into the olefin-based thermoplastic elastomer was changed to 100 parts by mass of magnesium oxide and 100 parts by mass of magnesium hydroxide.

[0054] [Comparative Example 1] A sample of Comparative Example 1 was manufactured in the same manner as in Example 1, except that the surface treatment of the conductive fabric A of the first component was not performed. Specifically, conductive fabric A was laminated directly onto the elastomer sheet of the second component and pressed in a press machine at a temperature of 200°C and a pressure of 1 MPa for 2 minutes.

[0055] [Comparative Example 2] A sample of Comparative Example 2 was prepared in the same manner as in Example 1, except that the surface treatment of the first component was changed from a citric acid aqueous solution to a hydrochloric acid aqueous solution (with the same concentration of 0.5 mol / L).

[0056] [Comparative Example 3] A sample for Comparative Example 3 was prepared in the same manner as in Example 1, except that the surface treatment of the first component was changed from an aqueous citric acid solution to an aqueous acetic acid solution (with the same concentration of 0.5 mol / L).

[0057] <Rating> The adhesion and contact resistance between the conductive fabric and the elastomer sheet in each fabricated bonded sample were evaluated. [Evaluation Method] First, each manufactured joint sample was punched out in a rectangular shape measuring 10 mm wide and 50 mm long, with the weave direction of the conductive fabric tilted at approximately 45 degrees, to create evaluation samples. Next, the evaluation samples were chucked at 10 mm from each end in the longitudinal direction, and placed on a benchtop tensile testing machine in a state where they were stretched 20% in the longitudinal direction from their natural state (unloaded state) of 30 mm in length (1.2 times the length of the natural state). A stretching cycle of stretching 3% in the same direction and then returning to its original state was repeated 10,000 times.

[0058] (1) Adhesion After the stretch test, the evaluation samples were visually inspected. Adhesion was evaluated as good (indicated by a circle in Table 1 below) if no lifting or peeling of the conductive fabric was observed, and as poor (indicated by a cross in the same table) if either lifting or peeling of the conductive fabric was observed.

[0059] (2) Contact resistance After the stretch test, the electrical resistance of the evaluation sample was measured. The electrode distance during measurement was 30 mm. The electrical resistance was then compared to that of the evaluation sample (untreated) from Comparative Example 1 before the stretch test. If the electrical resistance was the same or less, it was evaluated as no increase in contact resistance (indicated by a circle in Table 1 below), and if the electrical resistance was greater, it was evaluated as an increase in contact resistance (indicated by a cross in the same table). Note that the sample from Example 5 did not contain conductive carbon black and therefore did not have conductivity, so the contact resistance was not evaluated.

[0060] [Evaluation Results] Table 1 summarizes the composition of each bonded sample, the type of solution used for surface treatment, and the evaluation results. [Table 1]

[0061] As shown in Table 1, in the samples of Examples 1 to 5, in which surface treatment was performed using polycarboxylic acids, neither lifting nor peeling of the conductive fabric was observed, and the adhesion was good. Furthermore, in the samples of Examples 1 to 4, the contact resistance did not increase. In contrast, in the sample of Comparative Example 1, which was not surface-treated, and the samples of Comparative Examples 2 and 3, which were surface-treated using acids other than polycarboxylic acids, either lifting or peeling of the conductive fabric was observed, the desired adhesion could not be obtained, and the contact resistance also increased. [Industrial applicability]

[0062] The bonded structure of this disclosure can be used for connecting flexible electrodes and wiring in piezoelectric sensors, capacitance sensors, actuators, etc., connecting insulating layers (dielectric layers) and electrodes, and for joining organic materials and metals with large differences in Young's modulus. [Explanation of symbols]

[0063] 1: Joint, 10: First component, 11: Joint surface, 20: Second component, 30: Wiring, 31: Solder.

Claims

1. A first member having a joint surface with an exposed metal part, A second member is bonded to the joint surface of the first member and has a thermoplastic polymer and a basic substance. Equipped with, The metal part comprises one or more selected from nickel, tin, tin-nickel alloy, tin-bismuth alloy, tin-silver alloy, and tin-copper alloy, and the surface of the metal part is treated with a polycarboxylic acid. The compound is characterized in that the basic substance comprises one or more selected from magnesium hydroxide, magnesium oxide, aluminum oxide, aluminum hydroxide, calcium oxide, calcium hydroxide, calcium carbonate, silicon compounds, and carbon black.

2. The compound according to claim 1, wherein the polycarboxylic acid is water-soluble.

3. The composite according to claim 1, wherein the number of carbon atoms in the polycarboxylic acid is 6 or less.

4. The compound according to claim 1, wherein the polycarboxylic acid is at least one of succinic acid and citric acid.

5. The joint according to claim 1, wherein the first member is a conductive cloth.

6. The joint according to claim 1, wherein the metal part is a plated film.

7. A method for manufacturing a joint according to claim 1, A surface treatment step is performed in which the surface of the metal part of the first member is treated with the polycarboxylic acid by contacting the exposed joint surface of the metal part, which has one or more metals selected from nickel, tin, tin-nickel alloy, tin-bismuth alloy, tin-silver alloy, and tin-copper alloy, with a solution containing a polycarboxylic acid and drying it, and then A pressing step is performed by laminating a second member having a thermoplastic polymer and a basic substance onto the joint surface of the first member and pressing it under heating. It has, A method for producing a composite, characterized in that the basic substance comprises one or more selected from magnesium hydroxide, magnesium oxide, aluminum oxide, aluminum hydroxide, calcium oxide, calcium hydroxide, calcium carbonate, silicon compounds, and carbon black.

8. The method for producing the composite according to claim 7, wherein the number of carbon atoms in the polycarboxylic acid is 6 or less.

9. The method for producing the compound according to claim 7, wherein the polycarboxylic acid is at least one of succinic acid and citric acid.

10. The method for manufacturing a joint according to claim 7, wherein the first member is a conductive cloth.

11. The method for manufacturing a joined body according to claim 7, wherein the metal part is a plated film.

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