Method for manufacturing joined body, and electric-electronic component

Abstract

A method for manufacturing a joined body in which a columnar base material A, a thermoplastic film B, and a resin C are joined together in the stated arrangement order, the method sequentially comprising step 1 for wrapping the thermoplastic film B in the circumferential direction around at least a portion of the outer circumference of the columnar base material A, and step 2 for joining the resin C to the portion of the columnar base material A around which the thermoplastic film B has been wrapped, wherein the shear adhesive force of the thermoplastic film B at 80°C is at least 4.0 MPa with respect to the columnar base material A, and the peak value of tanδ in a temperature range of 0-200°C of the thermoplastic film B is at least 1.0 in a temperature-tanδ curve when the temperature of the thermoplastic film B is increased from 0°C to 200°C at a rate of 4°C / min at a measurement frequency of 10 Hz.

Description

Joint manufacturing method and electrical / electronic component

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

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

[0003] Terminal blocks are an example of a product that uses parts that require multi-materialization. Terminal blocks for external containers such as battery cases, inverters, and motors are configured to include at least an insulator and an electrode body inside. The electrode body often has a metal portion extending from a through-hole in the external container to exchange electricity with the outside. To protect the inside of the external container from defects 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. In particular, electronic devices often malfunction due to even slight moisture or dust, so high levels of adhesion (leak resistance) are required for the sealing parts.

[0004] For example, a technique for sealing the periphery of a metal terminal by insert molding, such as injection molding, using a resin material as a sealant is known. However, when a resin material is sealed around a metal by insert molding, there is a risk of leakage through gaps. In particular, when a resin material is sealed around a metal terminal, etc., superior leak resistance is required. Therefore, as a means for sealing a metal terminal, etc., with a resin material, for example, a method of applying a liquid adhesive or varnish to the metal terminal and then sealing with a resin material by insert molding has been investigated. Specifically, a technique is known in which a primer layer is formed by applying an in-situ polymerizing composition to an electrode body and polymerizing it, followed by forming a sealing portion (Patent Document 1, etc.). Another known technique is to form a terminal adhesive layer by immersing an external terminal in a bath filled with a cationic epoxy resin-based electrodeposition paint and passing a current through it, followed by forming a sealing member (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] The potting technique prevents the intrusion of water and other external air even if gaps occur. However, because the thermosetting resin is liquid during potting, not only is handling the liquid complicated, but prolonged heating or standing time is required for thermal curing, posing productivity challenges. Furthermore, when the metal surface is roughened in advance, as in Patent Document 1, the absence of a layer to relieve stress when the metal is repeatedly exposed to high and low temperatures (during thermal cycling) results in stress on the sealing resin, making it prone to peeling and posing challenges to adhesion resistance. Furthermore, gaps are likely to form between the roughened metal surface and the sealing resin, raising concerns about insufficient adhesion. Furthermore, when a liquid adhesive or varnish is applied to the metal in advance, as in Patent Document 2, the adhesive is liquid during application, which can take a long time to bond, potentially resulting in issues such as pot life (usable time) and labor. Furthermore, insufficient or uneven application can impair adhesion, and excessive application can lead to contamination risks, resulting in poor workability. Furthermore, when a thermosetting adhesive is used, the difference in the linear expansion coefficient between the metal and the sealing resin causes the metal and resin to shift during thermal cycles, putting stress on the adhesive layer, which cannot relieve the stress and can peel off, making leaks more likely. This is thought to be because the thermosetting adhesive layer does not have thermoplasticity and quickly breaks when it reaches the plastic deformation range.

[0007] Therefore, an object of the present invention is to provide a method for producing a bonded body that has a short bonding process time, is resistant to peeling even after thermal cycling, and has excellent adhesion, and to provide an electric / electronic component.

[0008] The present inventors have found that the above-mentioned problems can be solved by bonding a resin material and a substrate via a specific thermoplastic film.

[0009] [1] A method for producing a bonded body by bonding a columnar substrate A, a thermoplastic film B, and a resin C in this order, the method comprising the steps of: Step 1: wrapping the thermoplastic film B circumferentially around at least a portion of the outer periphery of the columnar substrate A; and Step 2: bonding the resin C to the portion of the columnar substrate A around which the thermoplastic film B is wrapped, wherein the thermoplastic film B has a shear adhesive strength of 4.0 MPa or more at 80°C to the columnar substrate A, and the thermoplastic film B has a peak tanδ of 1.0 or more in the temperature range of 0°C or more and 200°C or less in a temperature-tanδ curve obtained by heating the thermoplastic film B from 0°C to 200°C at a rate of 4°C / min at a measurement frequency of 10 Hz. [2] The method for producing a joined body according to [1], further comprising the step of joining the columnar substrate A and the thermoplastic film B by at least one method selected from the group consisting of contact heating, hot air heating, heat pressing, infrared heating, hot plate welding, ultrasonic welding, vibration welding, and high-frequency induction welding. [3] The method for producing a joined body according to [1] or [2], wherein the thickness of the thermoplastic film B is 10 μm or more and 3 mm or less. [4] The method for producing a joined body according to any one of [1] to [3], wherein the thermoplastic film B contains more than 50 mass% of an amorphous thermoplastic resin. [5] The method for producing a joined body according to [4], wherein the amorphous thermoplastic resin is at least one selected from the group consisting of a thermoplastic epoxy resin and a phenoxy resin. [6] The method for producing a joined body according to any one of [1] to [5], wherein the thermoplastic film B is a thermoplastic resin having an epoxy equivalent of 1,600 g / eq. or more or containing no epoxy groups. [7] The method for producing a joined body according to any one of [1] to [6], wherein the columnar substrate A is a metal. [8] An electric / electronic component comprising a bonded body obtained by the method for producing a bonded body according to any one of [1] to [7].

[0010] According to the present invention, it is possible to provide a method for producing a bonded body that requires a short bonding process time, is resistant to peeling even after thermal cycling, and has excellent adhesion, and an electric / electronic component.

[0011] 1 is a schematic diagram showing a configuration of one embodiment of a bonded body obtained by the method for producing a bonded body of the present embodiment.

[0012] Embodiments of the present invention will be described in detail below. In this specification, "bonding" means joining two objects together, with adhesion and welding being subordinate concepts. "Bonding" means joining two adherends (objects to be bonded) together using an organic material such as tape or adhesive (such as a thermosetting resin or a thermoplastic resin). "Welding" means joining two adherends (objects to be bonded) together by using heat to melt the surface of a thermoplastic resin or the like, followed by entanglement and solidification due to molecular diffusion during the cooling process. "Adhesion" means the property of having adhesive strength sufficient to join two objects together. "Adhesion" means the property of having adhesive strength between two objects. "Adhesion" and "adhesion" refer to different properties. In this specification, the term "bonding process time" refers to the time from the start point when the columnar substrate A constituting the bonded body comes into contact with the film to the end point when the fabrication of the bonded body is completed. In this specification, the term "A to B" indicating a numerical range refers to a numerical range including the endpoints A and B. That is, it means "A or more and B or less" (when A<B) or "A or less and B or more" (when A>B).

[0013] <Method for Manufacturing Bonded Body> The method for manufacturing a bonded body of this embodiment is a method for manufacturing a bonded body by bonding a columnar substrate A, a thermoplastic film B, and a resin C in this order, and is characterized by sequentially comprising: Step 1: circumferentially wrapping the thermoplastic film B around at least a portion of the outer periphery of the columnar substrate A; and Step 2: bonding the resin C to the portion of the columnar substrate A around which the thermoplastic film B is wrapped. The method is also characterized by: the shear adhesive strength of the thermoplastic film B to the columnar substrate A at 80°C is 4.0 MPa or more; and the peak value of tanδ of the thermoplastic film B in the temperature range of 0°C or more and 200°C or less is 1.0 or more in a temperature-tanδ curve obtained by heating from 0°C to 200°C at a rate of 4°C / min at a measurement frequency of 10 Hz. By providing the thermoplastic film B between the columnar substrate A and the resin C as a sealing material, the columnar substrate A and the resin C are bonded with excellent adhesion and are resistant to peeling even after undergoing thermal cycling. Furthermore, it can be said that directly contacting the thermoplastic film B with the columnar substrate A is an effective operation in shortening the bonding process compared to applying a liquid bonding agent, etc. Furthermore, by using a thermoplastic film B with a uniform thickness, uneven areas such as uncoated areas and dripping are prevented compared to when applying a liquid bonding agent, etc., and excellent adhesion can be achieved.

[0014] The detailed reasons why the effects of the present invention are achieved are considered as follows. During thermal cycling, the difference in linear expansion between the metal and the encapsulating resin causes the metal and the encapsulating resin to move relative to each other in the shear direction. The encapsulating resin / adhesive layer and the metal / adhesive layer also move in the shear direction. However, because the adhesive layer is a resin composition, the shear movement of the encapsulating resin / adhesive layer is small, while the movement of the metal / adhesive layer is greater. Therefore, in response to the shear movement of the metal / adhesive layer, shear deformation occurs near the interface of the adhesive layer, and stress is generated in the adhesive layer in response to the deformation of the adhesive layer. When the adhesive layer or the adhesive layer / metal interface is destroyed by this stress, the metal and the encapsulating resin peel off. The " / " symbol indicates the boundary between the layers.

[0015] In this embodiment, a thermoplastic film B in which a chemical reaction such as polymerization has been completed is provided as an adhesive layer between the columnar substrate A and the resin C. When the adhesive layer is heated to a temperature above the glass transition point, the adhesive layer softens due to the thermoplasticity, significantly increasing its flexibility, and the stress against deformation in the shear direction is significantly reduced. At this time, the loss modulus E" increases relative to the storage modulus E', and the ratio, loss tangent tanδ = E" / E', exceeds 1, entering a viscous region. On the other hand, although the adhesive strength decreases when the temperature is above the glass transition point, the improvement in flexibility is so significant that the stress is significantly reduced and is greater than the decrease in adhesive strength, making it difficult for the metal and the sealing resin to peel. Furthermore, at high temperatures during thermal cycles (e.g., 120°C or higher), the adhesive layer softens and changes from an elastic region (where stress occurs in proportion to strain) to a viscous region (where the increase in stress stops when the external force is removed), resetting the stress. This reduces accumulated fatigue during repeated thermal cycles and makes peeling less likely. Therefore, the use of thermoplastic film B allows for plastic deformation and effectively relieves stress, resulting in a bonded structure that is resistant to peeling during thermal cycling and has excellent adhesion. Furthermore, since thermoplastic film B, which is solid at room temperature, is used as the adhesive layer, handling of liquids is not required when forming the adhesive layer, simplifying the bonding process. Furthermore, because it is thermoplastic, the bonding process involves only a phase change between solid and liquid. Therefore, when thermoplastic film B is used, the bonding process time for adhesion to columnar substrate A is shorter than when a thermosetting resin, which involves a chemical reaction, is used.

[0016] [Columnar substrate A] The shape of the columnar substrate A is not particularly limited. The shape of the columnar substrate A may be, for example, a columnar shape having a circular, semicircular, elliptical, square, rectangular, triangular, or other polygonal cross section, or may be a rectangular strip or flat plate with a large aspect ratio of the cross section. Examples of the material of the columnar substrate A include metals, inorganic substances, and resins. One type of material for the columnar substrate A may be used alone, or two or more types may be used in combination. From the viewpoint of heat resistance and strength, the columnar substrate A is preferably a metal.

[0017] The metal used as the material for the columnar substrate A is not particularly limited, and examples thereof include aluminum, iron, copper, magnesium, titanium, etc. In this embodiment, the term "iron" is used to include iron and its alloys. Examples of iron alloys include steel and stainless steel. Similarly, copper, aluminum, magnesium, and titanium are also used to include these elements and their alloys. Furthermore, the surfaces of these metals may be subjected to metal plating depending on the application.

[0018] The inorganic material used as the material of the columnar substrate A is not particularly limited, and examples thereof include glass, ceramic, carbon molded body, etc. Examples of glass include general glass, heat-resistant glass, fireproof glass, fire-resistant glass, chemically strengthened glass used for protecting smartphones, etc. Specific examples thereof include soda-lime glass, lead glass, borosilicate glass, quartz glass, etc.

[0019] Examples of ceramics include fine ceramics used in semiconductors, automobiles, industrial equipment, etc. Specific examples include oxide-based ceramics such as alumina, zirconia, and barium titanate; hydroxide-based ceramics such as hydroxyapatite; carbide-based ceramics such as silicon carbide; and nitride-based ceramics such as silicon nitride.

[0020] Resins used as the material for the columnar substrate A include cured products of thermosetting resins such as glass fiber reinforced thermosetting resins, epoxy resins, vinyl ester resins, and unsaturated polyesters, as well as highly heat-resistant engineering plastics such as polyimide resins, polyetherimides, and polyethersulfones. When the material for the columnar substrate A is a resin, the resin must have a melting point or glass transition temperature that does not deform at the temperature during bonding in the bonding step (step 2).

[0021] The columnar substrate A may be subjected to an appropriate pretreatment. Pretreatments include surface cleaning and surface roughening. Specifically, when the columnar substrate A is made of aluminum, ceramic, or iron, at least one treatment selected from the group consisting of degreasing, UV ozone treatment, blasting, polishing, plasma treatment, and etching is preferred. When the columnar substrate A is made of fiber-reinforced plastic (FRP), polypropylene, polycarbonate, polymethyl methacrylate, polyetherimide, polyamide, or polybutylene terephthalate, at least one treatment selected from the group consisting of degreasing, UV ozone treatment, blasting, polishing, plasma treatment, and corona discharge treatment is preferred. Only one type of pretreatment may be used, or two or more types may be used. Specific methods for these pretreatments can be known methods.

[0022] [Thermoplastic film B] The thermoplastic film B is mainly composed of a thermoplastic resin. Furthermore, the thermoplastic film B preferably has adhesive properties to the columnar substrate A. In this specification, "main component" means the component with the highest content among the resin components in the thermoplastic film B. The content of the thermoplastic resin in the resin components is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. The thermoplastic film B preferably contains more than 50% by mass 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" means a resin composition mainly composed of a thermoplastic resin molded into a thin film.

[0023] <<Tan δ>> In a temperature-tan δ curve obtained by heating the thermoplastic film B from 0°C to 200°C at a rate of 4°C / min at a measurement frequency of 10 Hz, the peak value of tan δ for the thermoplastic film B in the temperature range of 0°C or higher and 200°C or lower is 1.0 or higher. When multiple tan δ peaks appear, the tan δ value of the lowest-temperature peak is used. If the peak value of tan δ is less than 1.0, the adhesive layer is in the elastic region and therefore does not have sufficient flexibility, resulting in destruction of the adhesive layer or the adhesive layer / metal interface, making it difficult to prevent peeling between the columnar substrate A and the resin C. The peak value of tan δ is preferably 100 or lower, more preferably 10 or lower.

[0024] The loss tangent (tanδ) is defined as the ratio of the storage shear modulus to the loss shear modulus, and is a value measured using a dynamic viscoelasticity measuring device. In this embodiment, the peak value of tanδ is measured using a test piece prepared using thermoplastic film B with a dynamic viscoelasticity measuring (DMA) device (for example, Rheogel-E4000 manufactured by UBM Corporation) under the following conditions: - Size of test piece: thickness 0.01 to 1 mm, width 5 mm, length 20 mm - Strain amount: 0.1 mm - Vibration waveform: sine wave - Frequency: 10 Hz - Measurement temperature: 0 to 200°C (or until melted) - Heating rate: 4°C / min Tan δ (loss tangent) is the ratio of the storage shear modulus (E") to the loss shear modulus (E'), i.e., the value of E" / E', and the peak value of tan δ is the peak value of tan δ in the temperature-tan δ curve at a measurement frequency of 10 Hz obtained by the DMA measurement. Note that in this embodiment, the method for measuring tan δ is as described in more detail in the Examples.

[0025] <<Shear Adhesion Strength>> The shear adhesive strength of the thermoplastic film B at 80 ° C. to the columnar substrate A is 4.0 MPa or more. From the viewpoint of more effectively suppressing peeling even after thermal cycling, the shear adhesive strength of the thermoplastic film B at 80 ° C. to the columnar substrate A is more preferably 5 MPa or more, and even more preferably 6 MPa or more. In addition, from the viewpoint of imparting moderate flexibility, the shear adhesive strength is preferably 50 MPa or less, more preferably 40 MPa or less. In this embodiment, the shear adhesive strength is measured using a test piece prepared by melting and solidifying a thermoplastic film B placed between two columnar substrates A to bond the columnar substrates A together, and after leaving it at 80 ° C. for 10 minutes or more at 80 ° C., in accordance with JIS K6850:1999, using a tensile tester in an 80 ° C. atmosphere. In addition, in this embodiment, the method for measuring the shear adhesive strength is described in more detail in the Examples.

[0026] In this specification, the melting point of a thermoplastic resin refers to the endothermic peak temperature during melting measured by DSC. When no endothermic peak is obtained or when the heat of fusion is 15 J / g or less, the melting point is considered to be the temperature obtained by adding 70°C to the glass transition temperature. Furthermore, in this specification, the glass transition temperature refers to the temperature at which the DSC curve begins 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, the melting point and glass transition temperature are values ​​measured by the method described in the Examples.

[0027] <<Amorphous Thermoplastic Resin>> Thermoplastic film B preferably contains more than 50% by mass of an amorphous thermoplastic resin. To fully impart the properties of an amorphous thermoplastic resin to thermoplastic film B, the content of the amorphous thermoplastic resin is more preferably 60% by mass or more, even 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 thermoplastic film B. An amorphous thermoplastic resin is a resin that does not have crystals or has 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 DSC (differential scanning calorimetry) and the weight of the thermoplastic resin component. When an inorganic filler or the like is contained in the film, it 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 from 23°C to 200°C or higher at a rate of 10°C / min using a DSC (DSC8231 manufactured by Rigaku Corporation) to obtain a DSC curve.Then, the mass can be calculated from the area of ​​the endothermic peak at the time of melting determined from the DSC curve and the weighed value.

[0028] 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 endothermic peak is below the detection limit. By using a thermoplastic film B mainly composed of an amorphous thermoplastic resin having a heat of fusion of 15 J / g or less, the rapid viscosity decrease seen in conventional hot melt adhesives does not occur during heating, and the adhesive does not reach a low viscosity (0.001 to 100 Pa s) even at high temperatures exceeding 200 ° C. Therefore, even in a molten state, the thermoplastic film B does not flow out from between the columnar substrate A and the resin C, and the thickness of the thermoplastic film B can be stably secured, and high adhesion can be stably obtained.

[0029] Furthermore, from the viewpoint of airtightness and toughness, the amorphous thermoplastic resin is preferably at least one selected from the group consisting of thermoplastic epoxy resins and phenoxy resins. Among these, from the viewpoint of airtightness and toughness, it is more preferable that thermoplastic film B mainly contains 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 thermoplastic film B mainly contains an amorphous thermoplastic resin that is at least one of a thermoplastic epoxy resin and a phenoxy resin, having an epoxy equivalent of 1,600 g / eq. or more and a heat of fusion of 15 J / g or less.

[0030] Thermoplastic epoxy resins and phenoxy resins have low cohesive strength within the resin and may contain hydroxyl groups, so they have strong interactions with the columnar substrate A and resin C, and are expected to be able to bond dissimilar materials with a stronger bonding strength than conventional crystalline hot melt adhesives.

[0031] In particular, from the viewpoint of storage stability, it is preferable that the thermoplastic film B has an epoxy equivalent of 1,600 g / eq. or more or is a thermoplastic resin that does not contain epoxy groups. The epoxy equivalent is more preferably 2,000 g / eq. or more, even more preferably 5,000 g / eq. or more, and even more preferably 9,000 g / eq. or more, and is particularly preferably above the detection limit so that epoxy groups are not substantially detected. Note that an epoxy equivalent of above the detection limit means that no epoxy groups are detected when the epoxy equivalent is measured according to JIS K 7236:2001, which will be described later. The epoxy equivalent (weight of the thermoplastic resin containing 1 mole of epoxy groups) referred to here is the epoxy equivalent value of the thermoplastic resin contained in the thermoplastic film B before bonding, and is a value (unit: "g / eq.") measured according to the method specified in JIS-K7236:2001. Specifically, a potentiometric titrator was used to add tetraethylammonium bromide acetate solution, and a 0.1 mol / L perchloric acid-acetic acid solution was used. The solvent-diluted product (resin varnish) was then titrated using a 0.1 mol / L perchloric acid-acetic acid solution, and the solids content was calculated from the nonvolatile content. In the case of a mixture of two or more resins, the value can also be calculated from the content and epoxy equivalent of each resin.

[0032] <<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.

[0033] (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.

[0034] 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.

[0035] Among the bifunctional compounds of (b), 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.

[0036] 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.

[0037] 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.

[0038] Physical Properties of Thermoplastic Epoxy Resins and Phenoxy Resins Thermoplastic epoxy resins and phenoxy resins preferably have a weight-average molecular weight (MW) of 10,000 to 500,000, more preferably 18,000 to 300,000, and even more preferably 20,000 to 200,000, as measured by gel permeation chromatography (GPC) in terms of polystyrene. The MW is calculated from the elution peak position detected by GPC, and each MW is a standard polystyrene-equivalent molecular weight. A MW within this range provides a good balance between thermoplasticity and heat resistance, allowing efficient melting to yield a bonded body with high heat resistance. A MW of 10,000 or higher provides excellent heat resistance, while a MW of 500,000 or lower provides low viscosity during melting and high bondability.

[0039] <<Components other than the resin component in the thermoplastic film B>> If necessary, the thermoplastic film B may contain a filler or an additive as a component other than the resin component, as long as the object of the present embodiment is not impaired.

[0040] Examples of fillers include inorganic fillers and organic fillers (such as resin powders). Examples of inorganic fillers include spherical fused silica, metal powders such as iron, silica sand, talc, calcium carbonate, mica, acid clay, diatomaceous earth, kaolin, quartz, titanium oxide, silica, and glass balloons. Examples of organic fillers include rubber microparticles, elastomer microparticles, core-shell particles, thermoplastic resin microparticles, thermosetting resin microparticles, and phenolic resin microballoons. When thermoplastic film B contains a filler, the content of the filler in 100% by volume of the total amount of thermoplastic film B is preferably 50% by volume or less, more preferably 30% by volume or less, even more preferably 20% by volume or less, and most preferably 10% by volume or less. The volume of the filler can be determined by dividing the weight of the filler contained in thermoplastic film B by the apparent specific gravity of the filler. The content of the resin component in the total amount (100% by volume) of the thermoplastic film B is preferably 10% by volume or more, more preferably 20% by volume or more, even more preferably 30% by volume or more, and even more preferably 50% by volume or more, and in one embodiment 80% by volume or more, in another embodiment 90% by volume or more, and in another embodiment 99% by volume or more.

[0041] Examples of additives include antifoaming agents, coupling agents such as silane coupling agents, pigments, tackifying resins, etc., and these may be contained alone or in combination of two or more. The content of additives in thermoplastic film B is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less. The content of resin components in thermoplastic film B is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and even more preferably 50% by mass or more, and in one embodiment 80% by mass or more, in another embodiment 90% by mass or more, and in another embodiment 99% by mass or more.

[0042] In one embodiment of the present invention, it is preferred that the amorphous thermoplastic resin is at least one selected from the group consisting of thermoplastic epoxy resins and phenoxy resins, the thermoplastic epoxy resin is a polymer of (a) a bifunctional epoxy resin monomer or oligomer and (b) a bifunctional compound having two identical or different functional groups selected from the group consisting of a phenolic hydroxyl group, a carboxyl group, a mercapto group, an isocyanate group, and a cyanate ester group (excluding polyhydroxypolyethers synthesized from bisphenols and epichlorohydrin), and the phenoxy resin is a polyhydroxypolyether synthesized from bisphenols and epichlorohydrin.

[0043] <<Form of Thermoplastic Film B>> Thermoplastic film B is a sheet-like material. The thickness of thermoplastic film B is preferably 10 μm or more and 3 mm or less. From the viewpoint of obtaining a firmly bonded bonded body in a short bonding process time, the thickness of thermoplastic film B is more preferably 1 mm or less, even more preferably 0.5 mm or less, even more preferably 0.3 mm or less, particularly preferably 0.2 mm or less, and most preferably 0.1 mm or less. Furthermore, from the viewpoint of further improving adhesion and peel resistance, the thickness of thermoplastic film B is more preferably 20 μm or more, even more preferably 30 μm or more, and even more preferably 40 μm or more. When the thickness of thermoplastic film B is within the above numerical range, it can be efficiently spread over the bonding surface with columnar substrate A by heating or the like, and high adhesion can be obtained.

[0044] The thermoplastic film B may be a single layer or a laminate consisting of multiple layers, but from the viewpoints of ease of production and improved adhesion, it is preferable that the thermoplastic film B be a single layer.

[0045] Furthermore, the thermoplastic film B may have tackiness to the extent that it does not impair the effects of the present invention. Tackiness can be imparted by mixing a tackifying resin into the thermoplastic resin constituting the thermoplastic film B, or by applying a pressure-sensitive adhesive to the surface of the thermoplastic film B. Tackiness may be imparted to one or both sides, but applying it to one side is more preferable because it allows tackiness to be imparted only to the surface in contact with the columnar substrate A, making it less likely that the adhesive surface will be exposed to the outside. The pressure-sensitive adhesive may be applied to the entire surface, or may be applied partially in a striped, dotted, lattice, or tiled pattern (a shape in which multiple squares are arranged with gaps between them). A small application area is preferred because the pressure-sensitive adhesive is less likely to protrude and be exposed from the edge of the thermoplastic film B, making it less likely to lose adhesion. Furthermore, the tackiness may be imparted to a small amount sufficient to provide anti-slip properties. In other words, when the thermoplastic film B is brought into contact with the columnar substrate A, the thermoplastic film B may not stick to the columnar substrate A, but may be sufficient to increase resistance (become less slippery) when a shear force is applied. A lower tackiness is preferred since it tends to increase adhesive strength and provides excellent peel resistance and adhesion.

[0046] <<Method for Producing Thermoplastic Film B>> The method for producing the thermoplastic film B is not particularly limited, but for example, a resin composition may be obtained by heating and polymerizing a monomer or oligomer of a bifunctional epoxy compound, and a solvent may be added to the obtained resin composition as needed, followed by coating the composition on a release film or the like, curing and drying, and applying pressure as needed to obtain the thermoplastic film B. The polymerization reaction may be carried out after coating on the release film, or after the solvent has been removed to obtain a film shape, or a combination of these.

[0047] [Resin C] Resin C is not particularly limited, but is preferably one that can be insert molded, and more preferably one selected from the group consisting of thermoplastic resins, thermosetting resins, and fiber-reinforced plastics (FRP). The thermoplastic resin refers to a resin that undergoes a phase change between melting and solidification during molding to form a molded article, while the thermosetting resin refers to a resin that undergoes a polymerization reaction during molding to form a molded article. From the viewpoints of peel resistance, adhesion, and ease of molding, Resin C is preferably one selected from the group consisting of thermoplastic resins and thermosetting resins. The thermoplastic resin is preferably one that can be injection molded at a heating temperature range of 200 to 400°C, and the thermosetting resin is preferably one that can be molded by injection molding, transfer molding, or compression molding at a heating temperature range of 40 to 200°C. However, Resin C is preferably different from the resin components that make up Thermoplastic Film B.

[0048] In this embodiment, the resin C may be used as a sealing member. Even when used as a sealing member, the resin C is preferably one that can be insert-molded.

[0049] Examples of thermoplastic resins include polyolefins and acid-modified products thereof, polystyrene, polymethyl methacrylate, AS resin, ABS resin, thermoplastic aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate, polyimide, polyamide, polyamideimide, polyetherimide, polyethersulfone, polyphenylene ether and modified products thereof, polyphenylene sulfide, polyoxymethylene, polyarylate, polyether ketone, polyether ether ketone, polyether ketone ketone, thermoplastic epoxy, and fiber-reinforced materials thereof. From the viewpoints of heat resistance, cost, ease of molding, etc., it is preferable to use at least one selected from polycarbonate, glass fiber-reinforced polyamide, glass fiber-reinforced polybutylene terephthalate, and glass fiber-reinforced polyphenylene sulfide.

[0050] Examples of thermosetting resins include epoxy resins, vinyl ester resins, phenolic resins, silicone resins, urethane resins, polyimide resins, urea resins, melamine resins, and unsaturated polyester resins. These thermosetting resins may be used alone or in combination of two or more. The thermosetting resin preferably includes an epoxy resin. Examples of epoxy resins include bifunctional epoxy resins and trifunctional or higher polyfunctional epoxy resins. Examples of bifunctional epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, modified bisphenol A epoxy resins, modified bisphenol F epoxy resins, and biphenyl epoxy resins. Examples of trifunctional or higher polyfunctional epoxy resins include phenol novolac epoxy resins, cresol novolac epoxy resins, trishydroxyphenylmethane epoxy resins, tetraphenylolethane epoxy resins, and dicyclopentadiene epoxy resins. These epoxy resins may be used alone or in combination of two or more. As the epoxy resin, preferably a bifunctional epoxy resin is used, and more preferably one or more selected from the group consisting of bisphenol F epoxy resins and bisphenol A epoxy resins are used. When an epoxy resin is used, the thermosetting resin preferably contains a phenolic resin as a curing agent for the epoxy resin. As the phenolic resin, preferably a novolac-type phenolic resin is used. Examples of novolac-type phenolic resins include phenol novolac resin, phenol aralkyl resin, trishydroxyphenylmethane novolac resin, cresol novolac resin, tert-butylphenol novolac resin, and nonylphenol novolac resin. These phenolic resins may be used alone or in combination of two or more.

[0051] The molding temperature (resin temperature) of Resin C is preferably 100 to 400° C., more preferably 150 to 350° C., and even more preferably 180 to 300° C. By molding within the range of 100 to 400° C., the thermoplastic film B is efficiently deformed and melted by heating, and effectively wets and spreads over the joining surface, resulting in high adhesion.

[0052] The combination of the material of the columnar substrate A and the resin C is not particularly limited.

[0053] [Step 1] In step 1, a thermoplastic film B is wrapped around at least a portion of the outer periphery of a columnar substrate A in the circumferential direction. Here, the term "at least a portion of the outer periphery" refers to at least a portion of the columnar substrate A in the longitudinal direction. Furthermore, the term "wrapping" refers to wrapping the thermoplastic film B around the columnar substrate A in the circumferential direction once or more than once. An example of an embodiment of step 1 will be described with reference to FIG. 1. FIG. 1 is a schematic diagram showing an example of an embodiment of a bonded structure. As shown in FIG. 1-1, the thermoplastic film B (B) may be wrapped around at least a portion of the outer periphery of the columnar substrate A (A). At this time, as shown in FIG. 1-1, a non-bonded portion (a) of the thermoplastic film B (B) may be present in a portion of the columnar substrate A (A), or the non-bonded portion (a) may not be present, or the non-bonded portion (a) may be present only at one end of the columnar substrate A (A). That is, it is sufficient that at least a part of the outer periphery of the columnar substrate A (A) is bonded to the resin C (C) via the thermoplastic film B (B), and the columnar substrate A (A) may have a part that is bonded to the resin C (C) without the thermoplastic film B (B) in between. From the viewpoint of easily achieving the effects of the present invention, it is preferable that the columnar substrate A (A) has non-bonded parts a at both ends.

[0054] In step 1, first, as shown in FIG. 1-1, a thermoplastic film B (B) is wound circumferentially around the outer periphery of a columnar substrate A (A). At this time, as shown in FIG. 1-1, the thermoplastic film B (B) may be wound so that it continuously covers the outer periphery of the columnar substrate A (A). Since the thermoplastic film B (B) is wound around the columnar substrate A (A) in the circumferential direction one or more times, there are no gaps at both ends of the wrapped thermoplastic film B (B), resulting in high sealing performance and excellent leak resistance. The thermoplastic film B may also have tackiness. From the viewpoint of ease of handling, it is preferable that the thermoplastic film B has tackiness and be temporarily fixed to the columnar substrate A. The thermoplastic film B may also be coated with an adhesive to the extent that it does not impair leak resistance, and then wrapped around the columnar substrate A and temporarily fixed. Commercially available adhesives can be used as the adhesive.

[0055] As described above, after wrapping the thermoplastic film B around the outer periphery of the columnar substrate A, the wrapped thermoplastic film B can be melted and solidified to bond the columnar substrate A and the thermoplastic film B. Specifically, as shown in FIG. 1-1, after wrapping the thermoplastic film B (B) around the columnar substrate A (A), the thermoplastic film B (B) may be melted and solidified. Because the thermoplastic film B (B) is thermoplastic, it can be bonded to the columnar substrate A (A) in close contact with the columnar substrate A (A). In this embodiment, the thermoplastic film B can be melted and solidified by bonding the resin C in the next step 2. Therefore, to simplify the process, the thermoplastic film B may not be melted and solidified after step 1, but may be melted and solidified by heating in the molding step of the resin C in step 2. On the other hand, by melting and solidifying the thermoplastic film B in advance, the columnar substrate A and the thermoplastic film B can be more reliably bonded together. Therefore, from the viewpoint of improving airtightness and leak resistance, it is preferable to melt and solidify the wrapped thermoplastic film B after step 1 to bond the columnar substrate A and the thermoplastic film B.

[0056] <<Melting and Solidification>> In bonding the columnar substrate A and the thermoplastic film B, the method for melting the thermoplastic film B may be at least one method selected from the group consisting of contact heating, hot air heating, heat pressing, hot plate welding, infrared heating, ultrasonic welding, vibration welding, and high-frequency induction welding. Among these, heat pressing or high-frequency induction welding is preferred from the viewpoints of ease of production and shortening the bonding process.

[0057] When the thermoplastic film B is melted by heating, the temperature of the joint between the columnar substrate A and the thermoplastic film B may be determined taking into consideration the heat resistance temperature of the material of the columnar substrate A, and is preferably 100 to 300° C., more preferably 120 to 250° C., and even more preferably 150 to 220° C. By joining at 100 to 300° C., the thermoplastic film B is efficiently deformed and melted, and effectively wets and spreads across the joint surface, thereby achieving high adhesion.

[0058] Methods for solidifying the molten thermoplastic film B include a method of allowing it to cool at room temperature and a method of allowing it to cool using a cooling device. "Room temperature" refers to a general room temperature within the range of 5 to 30°C. Among these, the method of allowing it to cool at room temperature is preferred from the viewpoint of ease of production. In this specification, "solidified" means a solid at room temperature, i.e., no fluidity at 23°C under no pressure.

[0059] [Step 2] In step 2, resin C is bonded to the portion of columnar substrate A around which thermoplastic film B is wrapped. A preferred method for bonding resin C is insert molding, from the viewpoint of obtaining a bonded body that is resistant to peeling even during the bonding process and undergoes thermal cycling and has excellent adhesion. Insert molding of resin C can cause thermoplastic film B to melt and solidify. Therefore, thermoplastic film B may be melted and solidified by heating in the molding process of resin C in step 2, without melting and solidifying it before step 2.

[0060] <Jointed Body> The joined body obtained by the method for producing a joined body of the present embodiment is formed by joining and integrating a columnar substrate A with a resin C via an adhesive layer formed by melting and then solidifying a thermoplastic film B.

[0061] The bonded body obtained by the method for producing a bonded body of this embodiment exhibits excellent adhesion even when it is a bonded body of different materials. Since adhesion is affected by many factors, including the strength of the interfacial interaction between the thermoplastic film B and the columnar substrate A, and between the thermoplastic film B and the resin C, as well as the thickness of the thermoplastic film B, the molecular weight and chemical structure of the polymer constituting the thermoplastic film B, the mechanical properties, and the viscoelastic properties, the details of the mechanism by which the bonded body exhibits excellent adhesion are not clear. Furthermore, the details of the relationship with the peak value of tan δ are also not clear.

[0062] In a more preferred embodiment of the bonded body, the thermoplastic film B is primarily composed of an amorphous thermoplastic resin, which is at least one of a thermoplastic epoxy resin and a phenoxy resin. Although the details of the mechanism by which this more preferred embodiment exhibits superior adhesion are not clear, it is presumed that the main factors are the low cohesive strength of the amorphous thermoplastic resin and, when hydroxyl groups are present in the resin, the formation of chemical bonds or intermolecular forces, such as hydrogen bonds or van der Waals forces, at the interface between the thermoplastic film B and the columnar substrate A and at the interface between the thermoplastic film B and the resin C.

[0063] However, in the above-mentioned bonded structure, the state or characteristics of the interface between the thermoplastic film B and the columnar substrate A, and the interface between the thermoplastic film B and the resin C are extremely thin chemical structures on the nanometer level or less, making them difficult to analyze. Therefore, it is impossible or impractical with current technology to identify the state or characteristics of the interface to distinguish it from one that does not use the thermoplastic film B.

[0064] The bonded body obtained by the method for producing a bonded body of the present embodiment is resistant to peeling between the columnar substrates A and the resin C even after thermal cycling and has excellent adhesion, and therefore can be suitably used in applications where these properties can be exerted. For example, an electric / electronic component including the bonded body obtained by the method for producing a bonded body of the present embodiment can be provided.

[0065] The joined body obtained by the joining body manufacturing method of the present embodiment can provide electric and electronic parts, more specifically, terminal blocks, bus bars, electric elements, etc. for automobiles and electric and electronic parts.

[0066] Hereinafter, the present embodiment will be specifically described with reference to examples and comparative examples, but the present embodiment is not limited to these.

[0067] In the examples and comparative examples, a bonded body was produced by bonding a columnar substrate A, a thermoplastic film B or a bonding agent, and a resin C in this order. Hereinafter, the layer made of the thermoplastic film B or the bonding agent will be referred to as an intermediate layer. The following materials were used in the examples and comparative examples. <Columnar substrate A> Columnar substrate (rectangular pillar): C1100 (tough pitch copper) with a width of 12.4 mm, a length of 64.9 mm, and a thickness of 1.6 mm <Thermoplastic film B> Films P-1 to P-5 produced in Examples 1-1 to 1-3 and 2 to 5 <Bonding agent> Bonding agents Q-1 to Q-6 produced in Comparative Examples 1 to 6 <Resin C> {PPS (polyphenylene sulfide)} FZ-1130-D5 (glass fiber 30% by mass) manufactured by DIC Corporation (melting point 280°C) {PC (polycarbonate)} 121R (softening point: 129°C, melting point 220°C) {PA6T} Ultramid T1000HG7 (glass fiber 35% by mass) manufactured by BASF (melting point 320°C)

[0068] <Melting Point, Glass Transition Temperature, and Epoxy Equivalent of Thermoplastic Film B and Binder> (Melting Point and Glass Transition Temperature) 2 to 10 mg of thermoplastic film B and binder 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 upon melting in the DSC curve and the weighed value. The endothermic peak temperature of the obtained DSC curve (the temperature of the endothermic peak in the DSC curve resulting from melting) was taken as the melting point (X°C). Note that if no endothermic peak was 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 by heating the sample to 200°C (10°C / min) using DSC, cooling it to 40°C or less (10°C / min), and then heating it further to 200°C. The temperature at which the DSC curve started to drop in the second cycle was recorded. Note that there was no melting point for thermosetting resins that do not melt when heated. The measurement results are shown in Tables 1 and 2.

[0069] (Epoxy equivalent) Measured according to JIS K-7236:2001 and converted into a value as resin solids. In the case of a simple mixture without reaction, it was calculated from the epoxy equivalent and content of each component. The calculation results are shown in Tables 1 and 2.

[0070] <Measurement of temperature-tan δ curve> Each thermoplastic film B was cut with a cutter to a size of 5 mm wide and 20 mm long to prepare a test piece for measuring tan δ. Using the test piece, measurement was performed under the following conditions using a dynamic viscoelasticity measuring (DMA) device (Rheogel-E4000 manufactured by UBM Corporation). The measurement frequency was fixed at 10 Hz, and the temperature was raised from 0°C to 200°C at a rate of 4°C / min, while the storage shear modulus (E") and loss shear modulus (E') were measured at each temperature to obtain a temperature-tan δ curve. The value of the first peak that appeared (on the lowest temperature side) within the measurement range was taken as the peak value of tan δ. Note that tan δ (loss tangent) was taken as the ratio of the storage shear modulus (E") to the loss shear modulus (E'), i.e., the value E" / E'. - Test piece size: thickness 0.01 to 1 mm, width 5 mm, length 20 mm - Strain amount: 0.1 mm - Vibration waveform: sine wave - Frequency: 10 Hz - Measurement temperature: 0 to 200°C (or until melted) - Heating rate: 4°C / min. Furthermore, a peak value of tan δ of 1 or more was evaluated as "A", and a peak value of tan δ of less than 1 was evaluated as "B". The evaluation results are shown in Tables 1 and 2.

[0071] <Evaluation of Surface Tackiness of Thermoplastic Film B and Adhesive> Each thermoplastic film B and each adhesive was pressed against a vertically standing glass plate in a room temperature atmosphere with a force of 10 N, and if it did not fall off the glass plate after the pressure was released, it was judged to have tackiness.

[0072] <Shear Adhesion Strength> Films P-1 to P-5 (15 mm x 25 mm) used in the Examples or bonding agents Q-1 to Q-5 used in the Comparative Examples were placed on a copper substrate (C1100, 25 mm x 100 mm x 1.6 mm thick) whose surface had been degreased by wiping with a cloth soaked in methyl ethyl ketone. Another copper substrate with a similarly treated surface was then placed on top of the film, sandwiched, and secured with clips. The overlap between these substrates was 25 mm wide and 12.5 mm deep. The laminate was heated at 200°C for 30 minutes and allowed to cool to room temperature. These test specimens were used to measure shear adhesion strength in accordance with JIS K6850:1999. The ambient temperature during measurement was 80°C. More specifically, the bonded body was allowed to stand at 80°C for 30 minutes or more, and then a tensile shear bond strength test was carried out in an 80°C atmosphere in accordance with ISO19095:2015 using a tensile tester (Universal Testing Machine Autograph "AG-X plus" (manufactured by Shimadzu Corporation); load cell 10 kN, tensile speed 10 mm / min) to measure the shear adhesive strength.

[0073] Example 1-1 (Film P-1) 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 phenoxy resin composition was applied to a release-treated PET film and heated at 140°C for 30 minutes to dry the solvent, yielding Film P-1 with a solids content of 100% by mass and a thickness of 40 μm. (Step 1) Film P-1 was wrapped around a columnar substrate A once, creating a 2-3 mm wrap. As shown in FIG. 1, a non-adhered portion (a) of the film P-1 (B) was provided, and the film P-1 (B) was wrapped around the columnar substrate A (A). Next, the columnar substrate A (A) wrapped with the film P-1 (B) was heated to 200 ° C. for 15 minutes, and the film P-1 (B) was melted. Thereafter, it was allowed to cool at room temperature for 1 minute, and the film P-1 (B) solidified, resulting in a film-attached columnar substrate in which the columnar substrate A (A) and the film P-1 (B) were bonded. (Step 2) Using an injection molding machine (manufactured by Toyo Machinery & Metal Co., Ltd., model name "Si-100-6s") and a molding die, PPS was insert-molded as the resin C into the portion of the film-attached substrate where the film P-1 (B) was wrapped, and the bonded columnar substrate A and resin C were obtained. 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. A schematic diagram of the bonded body of columnar substrate A (A) and resin C (C) obtained in step 2 is shown in Figure 1-2.

[0074] [Example 1-2] A bonded body was obtained in the same manner as in Example 1-1, except that in step 2, PC was used as resin C, and the insert molding conditions were an injection molding temperature (resin temperature) of 265°C, a mold temperature of 90°C, an injection speed of 8 mm / sec, an injection pressure of 100 MPa, a dwell pressure of 50 MPa, a dwell time of 8 seconds, and a cooling time of 30 seconds.

[0075] Example 1-3 A bonded body was obtained in the same manner as in Example 1-1, except that in step 2, PA6T was used as resin C, and the insert molding conditions were an injection molding temperature (resin temperature) of 340°C, a mold temperature of 155°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.

[0076] Example 2 (Film P-2) 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, and 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. To this was added 10% by mass (24 g) of KMP-605 (Shin-Etsu Silicones, silicone powder), and the mixture was stirred to disperse. The solvent was then removed to obtain a thermoplastic epoxy resin composition as a solid component. A non-adhesive fluororesin film (Nitoflon (registered trademark) No. 900UL, manufactured by Nitto Denko Corporation) was placed on the upper and lower plates of a press, and the thermoplastic epoxy resin composition was placed on the non-adhesive fluororesin film on the lower plate.The press was then heated to 160°C, and the thermoplastic epoxy resin composition was heat-compressed for 2 hours to obtain a film P-2 having a solid content of 100% by mass and a thickness of 40 μm. (Steps 1 and 2) A bonded body was obtained in the same manner as in Steps 1 and 2 of Example 1-1, except that Film P-2 was used instead of Film P-1.

[0077] Example 3 (Film P-3) 18 g of PhenoToto® YP-50S (phenoxy resin, weight-average molecular weight approximately 50,000, manufactured by Nippon Steel Chemical & Material Co., Ltd.), 2 g of YS Polystar K125 (terpene phenol resin, softening point 125°C, manufactured by Yasuhara Chemical Co., Ltd.), and 80 g of cyclohexanone were charged into a reactor equipped with a stirrer, reflux condenser, gas inlet tube, and thermometer, and the mixture was heated to 60°C with 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 phenoxy resin composition was applied to a release-treated PET film and heated at 140°C for 30 minutes to dry the solvent, yielding a 40 μm-thick film P-3. (Step 1) Film P-3 was wrapped around columnar substrate A once, creating a 2-3 mm lap. As shown in 1-1 in Figure 1, a non-bonded portion (a) of film P-3 was provided, film P-3 was wrapped around columnar substrate A, and heated at 200 ° C for 15 minutes to melt film P-3 (B). Thereafter, it was allowed to cool at room temperature for 1 minute to solidify film P-3 (B), forming a film-attached substrate in which columnar substrate A and film P-3 were bonded. (Step 2) A bonded body was obtained in the same manner as step 2 of Example 1-1, except that film P-3 was used instead of film P-1.

[0078] Example 4 A film P-4 having a thickness of 150 μm was obtained in Example 1-1, and a bonded body was obtained in the same manner as in Example 1-1, except that the film P-4 was used instead of the film P-1.

[0079] Example 5 (Film P-5) 12 g of PhenoToto (registered trademark) YP-50S (Nippon Steel Chemical & Material Co., Ltd., phenoxy resin, weight-average molecular weight approximately 50,000), 8 g of Carbodilite (Nisshinbo Chemical Co., Ltd., polycarbodiimide resin), and 80 g of cyclohexanone were charged into a reactor equipped with a stirrer, reflux condenser, gas inlet tube, and thermometer, and the mixture was heated to 60°C with stirring. After visually confirming dissolution, the mixture was cooled to 40°C to obtain a resin composition with a solids content of 20% by mass. The resin composition was applied to a release-treated PET film and heated at 140°C for 30 minutes to dry the solvent, yielding Film P-5 with a thickness of 40 μm. (Steps 1 and 2) A bonded assembly was obtained in the same manner as in Steps 1 and 2 of Example 1-1, except that Film P-5 was used instead of Film P-1.

[0080] [Example 6] (Film P-6) A crystalline polyamide-based hot melt adhesive film (ELFAN (registered trademark) NT-120, manufactured by Nihon Matai Co., Ltd.) was used to prepare Film P-6 having the thickness shown in Table 1. For Film P-6, the weight average molecular weight and epoxy equivalent could not be measured because it was insoluble in solvents. (Steps 1 and 2) A bonded body was obtained in the same manner as in Steps 1 and 2 of Example 1-1, except that Film P-6 was used instead of Film P-1.

[0081] Example 7 (Film P-7) 19 g of PhenoToto (registered trademark) YP-50S (phenoxy resin, weight-average molecular weight approximately 50,000, manufactured by Nippon Steel Chemical & Material Co., Ltd.), 1 g of Tamanol 803L (terpene phenol resin, softening point 145-160°C, manufactured by Arakawa Chemical Industries, Ltd.), and 80 g of cyclohexanone were charged into a reactor equipped with a stirrer, reflux condenser, gas inlet tube, and thermometer, and the mixture was heated to 60°C with 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 phenoxy resin composition was applied to a release-treated PET film and heated at 140°C for 30 minutes to dry the solvent, yielding a 40 μm-thick Film P-3. (Steps 1 and 2) A bonded assembly was obtained in the same manner as in Steps 1 and 2 of Example 1-1, except that Film P-7 was used instead of Film P-1.

[0082] Comparative Example 1 A bonded structure was obtained in the same manner as in Example 1-1, except that Film Q-1, which was a polycarbonate film (Iupilon FE-2000, manufactured by Mitsubishi Gas Chemical Company, Inc.), was used instead of Film P-1.

[0083] [Comparative Example 2] (Film Q-2) Film Q-2 was obtained in the same manner as in (Film P-3) of Example 3, except that JP-100 (epoxidized polybutadiene manufactured by Nippon Soda Co., Ltd.) was used instead of YS Polystar K125 (terpene phenol resin manufactured by Yasuhara Chemical). (Steps 1 and 2) A bonded body was obtained in the same manner as in Steps 1 and 2 of Example 3, except that Film Q-2 was used instead of Film P-3.

[0084] [Comparative Example 3] (Film Q-3) Film Q-3 was obtained in the same manner as above, except that YS Polystar T100 (terpene phenol resin, softening point 100°C, manufactured by Yasuhara Chemical Co., Ltd.) was used instead of YS Polystar K125 (terpene phenol resin, softening point 125°C, manufactured by Yasuhara Chemical Co., Ltd.). (Steps 1 and 2) A joined body was obtained in the same manner as steps 1 and 2 of Example 3, except that Film Q-3 was used instead of Film P-3.

[0085] Comparative Example 4 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 (manufactured by Mitsubishi Chemical Corporation, bisphenol A-type epoxy resin, molecular weight approximately 900), 1.0 equivalent (63 g) of Shounol (registered trademark) BRG-556 (manufactured by 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 with stirring under a nitrogen gas atmosphere. After visually confirming dissolution, the mixture was cooled to 40°C to obtain a thermosetting epoxy resin solution with a solids content of 20% by mass. The solvent was then removed from the mixture to obtain a thermoplastic epoxy resin composition as a solid component. A non-adhesive fluororesin film (Nitoflon (registered trademark) No. 900UL, manufactured by Nitto Denko Corporation) was placed on the upper and lower plates of a press, and the thermoplastic epoxy resin composition was placed on the non-adhesive fluororesin film on the lower plate.The press was then heated to 160°C, and the thermoplastic epoxy resin composition was heat-compressed for 2 hours to obtain a 40 μm-thick film Q-4. (Steps 1 and 2) A bonded body was obtained in the same manner as in Steps 1 and 2 of Example 1-1, except that Film Q-4 was used instead of Film P-3.

[0086] [Comparative Example 5] (Film Q-5) A thermosetting liquid epoxy adhesive BETAMETE 1496S (manufactured by Dupont, epoxy resin base) was applied to a release film, cured at 100°C for 1 hour, cooled, and peeled off from the release film to obtain Film Q-5 with a thickness of 100 µm. (Steps 1 and 2) A bonded body was obtained in the same manner as Steps 1 and 2 of Example 1-1, except that Film Q-5 was used instead of Film P-3.

[0087] Comparative Example 6 (Bonding Material Q-6) 20 g of Fenotote (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. The mixture was heated to 60 °C while stirring, and after visually confirming dissolution, cooled to 40 °C to obtain a liquid bonding agent Q-6 with a solids content of 20% by mass. (Step 1) The bonding agent Q-6 was applied to the columnar substrate A in a circumferential pattern to a width of 5 mm, left to stand in an oven at 140 °C for 30 minutes, and then cooled at room temperature to produce a substrate with an adhesive layer. (Step 2) A bonded body was obtained in the same manner as in Example 1-1, except that the substrate with the adhesive layer was used instead of the substrate with a film.

[0088] Comparative Example 7 A bonded structure was obtained in the same manner as in Example 1-1, except that Film Q-7, a polyethylene terephthalate film (Toyobo Ester Film E-5100, manufactured by Toyobo Co., Ltd.), was used instead of Film P-1.

[0089] [Comparative Example 8] (Film Q-8) Parts A and B of the thermosetting liquid epoxy adhesive Bondquick 5 (manufactured by Konishi Co., Ltd., two-component type, bisphenol A type epoxy resin, thiol-based curing agent, and amine-based curing agent) were mixed, applied to a release film, cured at 100°C for 1 hour, cooled, and peeled from the release film to obtain Film Q-8 with a thickness of 40 µm. (Steps 1 and 2) A bonded body was obtained in the same manner as in Steps 1 and 2 of Example 1-1, except that Film Q-8 was used instead of Film P-3.

[0090] <Workability> Workability was evaluated from the perspective of the bonding process time required for step 1 and handleability. When a film was used in step 1, the bonding process time was shorter than when a solution was used, and no dripping occurred, so the intermediate layer could be formed easily. Therefore, the workability when a film was used was evaluated as good, and is shown in Tables 1 and 2 as "good." Furthermore, the workability when a solution was used was evaluated as extremely poor compared to when a film was used, and is shown in Tables 1 and 2 as "poor."

[0091] <Leak Test> As shown in 1-3 of FIG. 1, a silicone braided hose H (inner diameter 9.5 mm, outer diameter 16.5 mm) was inserted into the assembly produced in each Example and Comparative Example, and a silicone resin adhesive was applied to the joint between the resin C and the hose H and the surrounding area to seal it. A cross-sectional view of the joint between the resin C and the hose H is shown in 1-4 of FIG. 1. Next, a plug coupler was attached to the end of the hose H to which the assembly was not attached, and connected to a compressor. The entire assembly at the end of the hose to which the assembly was attached was submerged in water, and air X was sent into the hose H at an air pressure of 0.1 MPaG toward the assembly, and air bubbles leaking out of the water were visually observed. This operation was performed on 10 assembly produced in each Example and Comparative Example, and the adhesion between the columnar substrate A and the resin C was evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 1 and 2. It should be noted that if no air bubbles are observed in the water, it can be considered that the air leakage rate is 1 ml / min or less. <Evaluation Criteria> A: No air bubbles were observed 10 times out of 10. 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.

[0092] <Leakage Test After Thermal Cycles> The bonded bodies produced in each of the Examples and Comparative Examples were subjected to 1,000 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 and 2.

[0093]

[0094]

[0095] The manufacturing method and bonded body of this embodiment are used, for example, in applications such as terminals, bus bars, and electric elements of automobiles and electric / electronic components, as well as in applications such as sealing parts for power modules and electric / electronic components such as semiconductor packages, but are not particularly limited to these exemplified applications.

[0096] a: Thermoplastic film B non-adhered portion A: Columnar substrate A B: Thermoplastic film B C: Resin C H: Hose X: Air D: Joint

Claims

1. A method for producing a bonded body obtained by bonding a columnar substrate A, a thermoplastic film B, and a resin C in the stated order, the method comprising the steps of: step 1, wrapping the thermoplastic film B in a circumferential direction around at least a portion of the outer periphery of the columnar substrate A; and step 2, bonding the resin C to the portion of the columnar substrate A around which the thermoplastic film B is wrapped, wherein the shear adhesive strength of the thermoplastic film B to the columnar substrate A at 80°C is 4.0 MPa or more, and the peak value of tan δ of the thermoplastic film B in the temperature range of 0°C or more and 200°C or less is 1.0 or more in a temperature-tan δ curve obtained by heating the substrate from 0°C to 200°C at a rate of 4°C / min at a measurement frequency of 10 Hz.

2. A method for producing a joined body according to claim 1, further comprising a step of joining the columnar substrate A and the thermoplastic film B by at least one method selected from the group consisting of contact heating, hot air heating, heat pressing, infrared heating, hot plate welding, ultrasonic welding, vibration welding and high frequency induction welding.

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

4. The method for producing a joined body according to claim 1 or 2, wherein the thermoplastic film B contains more than 50 mass% of an amorphous thermoplastic resin.

5. The method for producing a bonded body according to claim 4, wherein the amorphous thermoplastic resin is at least one selected from the group consisting of thermoplastic epoxy resins and phenoxy resins.

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

7. The method for producing a joint body according to claim 1 or 2, wherein the columnar substrate A is a metal.

8. An electric / electronic component comprising a bonded body obtained by the method for producing a bonded body according to claim 1 or 2.

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