Method for manufacturing bonded body

Abstract

The present invention relates to a technique for joining a member to be fitted having a portion to be fitted to a fitting member having a fitting portion to be fitted to the portion to be fitted of the member to be fitted, and provides a joining technique having a short joining process time, a long opening time, and excellent adhesiveness. This method for producing a bonded body is provided with: a pre-bonding step for preparing a laminate by disposing, in this order, a base material A, which is a member to be fitted having a section to be fitted, a solid-state adhesive containing an amorphous thermoplastic resin, and a base material B, which is a material to be fitted having a section to be fitted, in this order, and a bonding step for bonding the base material A, the solid-state adhesive containing an amorphous thermoplastic resin and the solid-state adhesive containing an amorphous thermoplastic resin; the amorphous thermoplastic resin is at least one type selected from the group consisting of thermoplastic epoxy resins and phenoxy resins, and the base material (B) is a fitting member having a fitting part to which a fitting part of the fitting member is fitted; a bonding step for bonding the base material A and the base material B by heating and pressurizing the laminate to melt the solid binder; the amorphous thermoplastic resin has an epoxy equivalent of 1,600 or more or does not contain an epoxy group, and has a heat of fusion of 15 J / g or less.

Description

Technical Field

[0001] The present invention relates to a method for producing a joined body, which is suitable for applications in which dissimilar materials can be joined easily and firmly. Background Art

[0002] In recent years, the trend toward multi-material components has been gaining momentum in various fields, including automotive parts, medical devices, and home appliances, driven by the need for lighter weight and higher performance. Multi-material components are a method for achieving lighter weight and higher strength by combining materials with different functions and properties (hereinafter referred to as dissimilar materials). To achieve this multi-material approach, technologies for firmly joining dissimilar materials are essential.

[0003] As a means for firmly joining dissimilar materials, thermosetting epoxy resin adhesives (such as Patent Document 1) as liquid adhesives are widely used.

[0004] Joining using a liquid adhesive requires a coating step of applying a liquid resin composition and a curing step of curing the resin composition by polymerizing it after coating.

[0005] Therefore, when a liquid adhesive is used for bonding, it takes time to apply the resin composition in the coating step and time to perform the polymerization reaction in the curing step (ie, the bonding process takes a long time), resulting in a problem of lack of convenience.

[0006] In this specification, the term "bonding process time" refers to the time from the time at least one substrate constituting the bonded structure comes into contact with the adhesive, to the time when the bonded structure is completed. For example, this includes the time required to apply a liquid adhesive to the substrates, the drying step, or the step of applying a solid adhesive, and the time required to bond the substrates together (e.g., curing the adhesive layer).

[0007] There is also disclosed a technique for producing a joined body by impregnating or coating a substrate with an epoxy resin composition and then semi-curing (B-stage) the composition to form a laminate with an adhesive layer in a B-stage state (Patent Document 2, etc.).

[0008] However, bonding using an adhesive in a B-stage state also requires a curing step of causing the semi-cured adhesive layer to undergo a polymerization reaction and cure, which has the problem of a long bonding process time.

[0009] Furthermore, adhesives in the B-stage state have poor storage stability and cannot be stored at room temperature for long periods of time. They must be stored at low temperatures, resulting in a short open time and a lack of convenience.

[0010] In this specification, open time refers to the time limit from applying or placing adhesive on substrate A until substrate B is placed. Within this open time, the adhesive's adhesion does not decrease, allowing substrates A and B to be bonded with sufficient adhesion. The longer the open time, the longer the time limit from applying or placing adhesive on substrate A until substrate B is placed, and the greater the convenience.

[0011] As a means of joining dissimilar materials, thermoplastic adhesive compositions (hereinafter referred to as hot melt adhesives) are also used (Patent Document 3, etc.). The use of hot melt adhesives, specifically, because they utilize a phase transition without a polymerization reaction for bonding, eliminates the need for a coating process, resulting in a fast curing time (i.e., a short joining process time), and excellent convenience. Furthermore, they can be stored at room temperature for long periods of time, resulting in a long open time, which is also excellent in terms of convenience.

[0012] However, conventional hot-melt adhesives, often made from crystalline resins or resins containing crystalline resins to reduce melt viscosity, exhibit high cohesive strength within the adhesive resin and lack sufficient interaction with the substrate. Furthermore, during melt bonding, these adhesives exhibit low viscosity at high temperatures, making them prone to flow from the bonding surface. Furthermore, viscosity control is difficult, resulting in unstable film thickness. These factors have hindered the ability of conventional hot-melt adhesives to consistently achieve high bonding strength.

[0013] Prior art literature

[0014] Patent Literature

[0015] Patent Document 1: Japanese Patent Application Publication No. 2019-157018

[0016] Patent Document 2: Japanese Patent Application Laid-Open No. 10-17685

[0017] Patent Document 3: Japanese Patent Application Laid-Open No. 10-168417 Summary of the Invention

[0018] Problems to be solved by the invention

[0019] As described above, in the prior art, thermosetting epoxy resin adhesives with excellent adhesion have at least one of the problems of long bonding process time and short open time in both liquid and B-stage states. Hot melt adhesives with short bonding process time and long open time have the problem of being unable to stably obtain high bonding strength.

[0020] The present invention was completed in view of this technical background, and its purpose is to provide a technology for joining a substrate A and a substrate B, wherein the substrate A is a fitted component having a fitted portion, and the substrate B is a fitting component having a fitting portion that fits with the fitted portion of the fitted component. The joining technology has a short joining process time, a long open time and excellent adhesion.

[0021] Means of solving the problem

[0022] In order to achieve the above-mentioned object, the present invention provides the following means.

[0023] It should be noted that, in this specification, "joining" refers to connecting objects together, and "adhesion" and "fusion" are subordinate concepts. Adhesion refers to the joining of two adherends (materials to be bonded) using an organic material (thermosetting resin, thermoplastic resin, etc.) such as tape or adhesive. Fusion refers to the use of heat to melt the surface of a thermoplastic resin, etc., and then forming a bond through contact pressure and cooling, thereby utilizing entanglement and crystallization based on molecular diffusion.

[0024] <Method for Manufacturing Joined Body>

[0025] [1] A method for manufacturing a bonded body, comprising a pre-bonding step and a bonding step.

[0026] The pre-joining step comprises: sequentially arranging a substrate A, a solid bonding agent, and a substrate B to prepare a laminate, wherein the substrate A is a member to be joined having a portion to be joined, the solid bonding agent comprises an amorphous thermoplastic resin, the amorphous thermoplastic resin being at least one selected from a thermoplastic epoxy resin and a phenoxy resin, and the substrate B is a joining member having a joining portion to be joined with the joining portion of the member to be joined;

[0027] The bonding step includes heating and pressurizing the laminate to melt the solid bonding agent, thereby bonding the substrate A and the substrate B;

[0028] The amorphous thermoplastic resin has an epoxy equivalent of 1,600 or more or contains no epoxy group, and has a heat of fusion of 15 J / g or less.

[0029] [2] The method for manufacturing a joined body according to [1], wherein the engaged member is made of metal or resin, and the engaging member is made of metal.

[0030] [3] The method for producing a joined body according to [1] or [2], wherein the fitting portion is heated to 100 to 400° C. for fitting.

[0031] [4] A method for manufacturing a bonded body, which is a method for manufacturing a bonded body formed by sequentially bonding a substrate A, a solid bonding agent, and a substrate B, wherein the substrate A is a bonded component having a bonded portion, the solid bonding agent contains an amorphous thermoplastic resin, the amorphous thermoplastic resin is at least one selected from thermoplastic epoxy resins and phenoxy resins, and the substrate B is a bonding component having a bonding portion that is bonded to the bonded portion of the bonded component; or a method for manufacturing a bonded body formed by sequentially bonding a substrate A, a solid bonding agent, and a substrate B, wherein the substrate A is a bonding component having a bonding portion that is bonded to the bonded portion of the bonded component, the solid bonding agent contains an amorphous thermoplastic resin, the amorphous thermoplastic resin is at least one selected from thermoplastic epoxy resins and phenoxy resins, and the substrate B is the bonded component;

[0032] The method comprises a first bonding step and a second bonding step.

[0033] The first bonding step comprises: melting the solid bonding agent and then solidifying the solid bonding agent in a state where the solid bonding agent is in surface contact with the substrate A, thereby bonding the substrate A and the solid bonding agent;

[0034] The second bonding step comprises: melting and then solidifying the solid bonding agent bonded to the substrate A in a state where the solid bonding agent is in surface contact with the substrate B, thereby bonding the substrate A and the substrate B;

[0035] The amorphous thermoplastic resin has an epoxy equivalent of 1,600 g / eq. or more or contains no epoxy group, and has a heat of fusion of 15 J / g or less.

[0036] [5] The method for manufacturing a bonded body according to [4], wherein in the first bonding step, the solid bonding agent is heated to 100 to 300° C. to be melted and then solidified.

[0037] [6] According to the method for manufacturing a joined body described in [4] or [5], in the second joining step, the solid joining agent is melted and then solidified by at least one selected from contact heating, warm air heating, hot pressing, infrared heating, hot plate welding, ultrasonic welding, vibration welding and high-frequency induction welding.

[0038] [7] The method for manufacturing a bonded body according to any one of [4] to [6], wherein in the second bonding step, the solid bonding agent is melted and then solidified at a heating temperature of 100 to 400° C. and a pressure of 0.01 to 20 MPa.

[0039] [8] The method for producing a bonded body according to any one of [1] to [7], wherein the solid bonding agent before melting has a film shape.

[0040] <Joint>

[0041] [9] A joined body formed by joining a substrate A and a substrate B via an adhesive layer, wherein the substrate A is a fitted member having a fitted portion, and the substrate B is a fitting member having a fitting portion that fits with the fitted portion of the fitted member;

[0042] The adhesive layer is formed by placing a solid adhesive comprising an amorphous thermoplastic resin between the substrate A and the substrate B, heating and pressurizing the resin to melt it, and then curing the solid adhesive. The amorphous thermoplastic resin is at least one selected from a thermoplastic epoxy resin and a phenoxy resin, and has an epoxy equivalent of 1,600 or greater and a heat of fusion of 15 J / g or less.

[0043]

[10] The bonded body according to [9], wherein the heating and pressurizing are performed under the conditions of 100 to 400°C and 0.01 to 20 MPa.

[0044] Effects of the Invention

[0045] According to the present invention, a technology for joining a fitted component having an fitted portion and a fitting component, wherein the fitting component has a fitting portion that fits with the fitted portion of the fitted component, can provide a joining technology with a short joining process time, a long open time, and excellent adhesiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a cross-sectional view showing the structure of a bonded body according to one embodiment of the present invention.

[0047] Figure 2 This is a cross-sectional view showing the structure of a bonded body according to another embodiment of the present invention.

[0048] Modes for Carrying Out the Invention

[0049] [Method for Manufacturing a Joined Body_Embodiment 1]

[0050] The manufacturing method of the joint body of embodiment 1 includes a pre-joining process and a joining process, wherein the pre-joining process is to sequentially arrange a substrate A, a solid adhesive and a substrate B to prepare a laminate, wherein the substrate A is a joined component having a joined portion, the solid adhesive contains an amorphous thermoplastic resin, and the amorphous thermoplastic resin is at least one selected from thermoplastic epoxy resins and phenoxy resins, and the substrate B is a joining component having a joining portion that is joined with the joined portion of the joined component; and the joining process is to heat and pressurize the laminate to melt the solid adhesive, thereby joining the substrate A and the substrate B.

[0051] In the pre-bonding step, the substrate A and the solid adhesive, and the substrate B and the solid adhesive are not bonded together, but are bonded together in the subsequent bonding step. The solid adhesive may also be viscous, in which case the solid adhesive is temporarily fixed to the substrates in the pre-bonding step.

[0052] The shapes of the base material A as the member to be fitted and the base material B as the fitting member are not particularly limited, but are preferably cylindrical in view of ease of fitting and ease of processing.

[0053] The outer diameter of the fitted portion may be tapered toward the distal end, and the inner diameter of the fitting portion may be enlarged toward the distal end.

[0054] The engaged portion may be a recessed portion, and the engaging portion may be a convex portion.

[0055] The sum of the inner diameter of the interlocking portion and the thickness of the solid bonding material is preferably the same as or smaller than the outer diameter of the interlocking portion. Heating the substrate B increases the inner diameter of the interlocking portion, facilitating insertion into the interlocking portion. Cooling the substrate reduces the inner diameter of the interlocking portion, resulting in a secure bond.

[0056] The base material of the fitted member having the fitted portion is preferably made of metal or resin, and the base material of the fitting member having the fitting portion is preferably made of metal.

[0057] Examples of metals include aluminum, iron, titanium, magnesium, stainless steel, and copper. Among these, aluminum is particularly preferred due to its lightness and ease of processing. It should be noted that in this disclosure, the term "aluminum" is used to encompass aluminum and its alloys. Similarly, iron, titanium, magnesium, and copper are used to encompass their individual elements and their alloys.

[0058] The resin is not particularly limited and may be a common synthetic resin. Examples include resins used in automobile parts, such as polycarbonate resins, polyester resins, polybutylene terephthalate resins, and polyetherimide resins. Examples include carbon fiber reinforced resins (CFRP) and glass fiber reinforced resins (GFRP), such as press-molded products such as sheet molding compounds (SMC) and bulk molding compounds (BMC) using carbon fibers.

[0059] Hereinafter, each step will be described.

[0060] <Pre-joining process>

[0061] In the pre-bonding step, a substrate A, a solid bonding agent containing an amorphous thermoplastic resin, and a substrate B are sequentially arranged to prepare a laminate. The amorphous thermoplastic resin is at least one selected from thermoplastic epoxy resins and phenoxy resins.

[0062] The laminated body is formed by laminating independent members without bonding the substrate A and the solid adhesive, or the solid adhesive and the substrate B.

[0063] The "solid" in the solid adhesive means that it is solid at room temperature, that is, it has no fluidity in an unpressurized state at 23°C.

[0064] The solid adhesive preferably has the property of maintaining its shape without deformation or deterioration for 30 days or more in an unpressurized state at 23°C.

[0065] (Solid adhesive)

[0066] The solid adhesive includes an amorphous thermoplastic resin, which is at least one selected from thermoplastic epoxy resins and phenoxy resins, has an epoxy equivalent of 1,600 or more, and has a heat of fusion of 15 J / g or less.

[0067] The amorphous resin in the present invention refers to a resin that has a melting point (Tm) in the measurement using a differential scanning calorimeter (DSC), but does not have a clear endothermic peak (melting point) accompanied by melting, or the endothermic peak (melting point) is very small. The heat of fusion is calculated from the area of the endothermic peak of DSC and the weight of the thermoplastic resin component. In the case where the solid adhesive contains an inorganic filler, etc., it is calculated from the weight of the resin component from which the inorganic filler is removed. Specifically, the amorphous thermoplastic resin in the present invention refers to the following substances. 2-10 mg of a sample is weighed, placed in an aluminum pan, and heated from 23°C to 200°C or above at 10°C / min using DSC (DSC8231 manufactured by Rigaku Co., Ltd.) to obtain a DSC curve. Then, when the heat of fusion is calculated based on the area of the endothermic peak during melting obtained from the DSC curve and the above-mentioned weighed value, the heat of fusion is 15 J / g or less.

[0068] To ensure that the properties of the amorphous thermoplastic resin are sufficiently imparted to the solid adhesive, the content of the amorphous thermoplastic resin in the resin component of the solid adhesive is preferably 51% by mass or greater, more preferably 60% by mass or greater, even more preferably 70% by mass or greater, particularly preferably 80% by mass or greater, and most preferably 90% by mass or greater. In this disclosure, the term "resin component in the solid thermally conductive material" refers to the components of the solid thermally conductive material other than fillers.

[0069] The heat of fusion is 15 J / g or less, preferably 11 J / g or less, more preferably 7 J / g or less, further preferably 4 J / g or less, and most preferably the melting peak is below the detection limit.

[0070] The epoxy equivalent is 1,600 or more, preferably 2,000 or more, more preferably 5,000 or more, further preferably 9,000 or more, and most preferably it is above the detection limit and substantially no epoxy group is detected.

[0071] By using a solid adhesive composed of an amorphous thermoplastic resin with an epoxy equivalent of 1,600 or greater and a heat of fusion of 15 J / g or less, the adhesive does not experience the rapid drop in viscosity seen in conventional hot-melt adhesives when heated. Even at high temperatures exceeding 200°C, the adhesive does not reach a low viscosity (0.001 to 100 Pa·s). Consequently, the solid adhesive does not flow out of the laminate even in a molten state, ensuring a stable adhesive layer thickness and consistently high bonding strength.

[0072] The epoxy equivalent (the weight of the resin containing one mol of epoxy groups) referred to herein is the epoxy equivalent of the thermoplastic epoxy resin or phenoxy resin component contained in the solid adhesive before bonding, and is measured using the method specified in JIS-K7236:2001 (unit: "g / eq."). Specifically, a potentiometric titrator is used, using cyclohexanone as the solvent, tetraethylammonium bromide in acetic acid solution, and a 0.1 mol / L perchloric acid-acetic acid solution. The solvent dilution (resin varnish) is calculated as a solids equivalent from the non-volatile content. Note that in the case of a mixture of two or more resins, the epoxy equivalent can also be calculated from the respective contents and epoxy equivalents.

[0073] The melting point of the amorphous thermoplastic resin contained in the solid adhesive is preferably 50°C to 400°C, more preferably 60°C to 350°C, and even more preferably 70°C to 300°C. By setting the melting point within the range of 50°C to 400°C, the solid adhesive efficiently deforms and melts upon heating, effectively wetting and spreading on the bonding surface, thereby achieving high bonding strength.

[0074] In this specification, the melting point of an amorphous thermoplastic resin refers to a temperature range in which the resin softens substantially from a solid state, becomes thermoplastic, and is capable of melting and bonding.

[0075] Conventional thermosetting adhesives have been difficult to disassemble and separate (i.e., poorly recyclable) from the dissimilar materials that make up the bonded structure. Furthermore, if the bonded structure shifts during the manufacturing process, or if the contents or adherends become defective and need to be replaced, reattachment becomes difficult (i.e., poorly repairable), leading to inconvenience. However, the aforementioned solid adhesives soften and melt with heat, allowing for easy peeling and excellent recyclability. Furthermore, since they are thermoplastic, they can be reversibly softened, melted, and cured repeatedly, resulting in excellent repairability.

[0076] Thermoplastic Epoxy Resins

[0077] 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 phenolic hydroxyl groups, carboxyl groups, mercapto groups, isocyanate groups, and cyanate groups.

[0078] By using this compound, the polymerization reaction to form a linear polymer proceeds preferentially, and a thermoplastic epoxy resin having desired properties can be obtained.

[0079] The (a) bifunctional epoxy resin monomer or oligomer is an epoxy resin monomer or oligomer having two epoxy groups in the molecule.

[0080] Specific examples of the above-mentioned (a) include, for example, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bifunctional phenol novolac type epoxy resins, bisphenol AD type epoxy resins, biphenyl type epoxy resins, bifunctional naphthalene type epoxy resins, bifunctional alicyclic epoxy resins, bifunctional glycidyl ester type epoxy resins (e.g., diglycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl dimer acid diglycidyl ester, etc.), bifunctional glycidylamine type epoxy resins (e.g., diglycidyl aniline, diglycidyl toluidine, etc.), bifunctional heterocyclic epoxy resins, bifunctional diaryl sulfone type epoxy resins, hydroquinone type epoxy resins (e.g., hydroquinone diglycidyl ether, 2,5-di-tert-butyl Examples of the present invention include difunctional alkylene glycidyl ether compounds (e.g., butylene glycol diglycidyl ether, butene glycol diglycidyl ether, butynediol diglycidyl ether, etc.), difunctional glycidyl group-containing hydantoin compounds (e.g., 1,3-diglycidyl-5,5-dialkylhydantoin, 1-glycidyl-3-(glycidyloxyalkyl)-5,5-dialkylhydantoin, etc.), difunctional glycidyl group-containing siloxanes (e.g., 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane, α,β-bis(3-glycidyloxypropyl)polydimethylsiloxane, etc.), and modified products thereof. Among these, bisphenol A epoxy resins, bisphenol F epoxy resins, and biphenyl epoxy resins are preferred from the perspectives of reactivity and handleability.

[0081] Examples of the bifunctional compound having a phenolic hydroxyl group (b) include monocyclic 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 into which an allyl group is introduced such as diallylresorcinol, diallylbisphenol A, and triallyldihydroxybiphenyl; and dibutylbisphenol A.

[0082] Specific examples of the carboxyl group-containing compound (b) include adipic acid, succinic acid, malonic acid, cyclohexanedicarboxylic acid, phthalic acid, isophthalic acid, and terephthalic acid.

[0083] Examples of the bifunctional compound having a mercapto group (b) include ethylene glycol bismercaptoacetate and ethylene glycol bismercaptopropionate.

[0084] Specific examples of the isocyanate group-containing bifunctional compound (b) include diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HMDI), and toluene diisocyanate (TDI).

[0085] Specific examples of the cyanate group-containing bifunctional compound (b) include 2,2-bis(4-cyanatophenyl)propane, 1,1-bis(4-cyanatophenyl)ethane, and bis(4-cyanatophenyl)methane.

[0086] In the above (b), from the perspective of obtaining a thermoplastic polymer, a bifunctional compound having a phenolic hydroxyl group is preferred. From the perspective of heat resistance and adhesion, a bifunctional compound having two phenolic hydroxyl groups and a bisphenol structure or a biphenyl structure is preferred. From the perspective of heat resistance and cost, bisphenol A, bisphenol F or bisphenol S is preferred.

[0087] When the above-mentioned (a) is a bisphenol A-type epoxy resin, a bisphenol F-type epoxy resin, a bisphenol S-type epoxy resin, or a biphenyl-type epoxy resin, and the above-mentioned (b) is bisphenol A, bisphenol F, or bisphenol S, the polymer obtained by polymerization of the above-mentioned (a) and (b) has a structure in which a p-phenylene structure and an ether bond are the main skeleton, a main chain formed by linking these with an alkylene group, and hydroxyl groups generated by addition polymerization are arranged on the side chains.

[0088] The linear structure composed of a p-phenylene backbone improves the mechanical strength of the polymer after polymerization, and the hydroxyl groups arranged on the side chains enhance adhesion to substrates. This results in high bonding strength while maintaining the operability of thermosetting resins. Furthermore, in the case of thermoplastic resins, thermal softening and melting allow for recycling and repair, improving recyclability and repairability, which are problematic issues with thermosetting resins.

[0089] Phenoxy Resin

[0090] Phenoxy resin is a polyhydroxy polyether synthesized from bisphenols and epichlorohydrin, and has thermoplastic properties. In the manufacture of phenoxy resin, there are known methods of utilizing the direct reaction of dihydric phenols with epichlorohydrin, and methods of utilizing the polyaddition reaction of diglycidyl ethers of dihydric phenols with dihydric phenols. The phenoxy resin used in the present invention can be obtained by any of the methods. In the case of the direct reaction of dihydric phenols with epichlorohydrin, examples of dihydric phenols include phenols such as bisphenol A, bisphenol F, bisphenol S, biphenol, biphenylene glycol, and fluorene diphenyl; and aliphatic diols such as ethylene glycol, propylene glycol, and diethylene glycol. Among them, bisphenol A, bisphenol F, and bisphenol S are preferred from the perspectives of cost, adhesion, viscosity, and heat resistance. One of these can be used alone, or two or more can be used in combination.

[0091] Phenoxy resin has a chemical structure similar to that of epoxy resin, and has a structure in which a p-phenylene structure and an ether bond are the main skeleton, and hydroxyl groups are arranged on the main chain and side chains connecting these structures.

[0092] Physical Properties of Thermoplastic Epoxy Resins and Phenoxy Resins

[0093] For the above-mentioned thermoplastic epoxy resin and phenoxy resin, the polystyrene conversion value obtained by GPC (gel permeation chromatography) measurement, i.e., the weight average molecular weight, is preferably 10,000 to 500,000, more preferably 18,000 to 300,000, and further preferably 20,000 to 200,000. The weight average molecular weight is the value of the molecular weight calculated by the elution peak position detected by GPC and converted by standard polystyrene. If the weight average molecular weight is within this range, the balance between thermoplasticity and heat resistance is good, and a joint body can be efficiently obtained by melting, and its heat resistance also becomes higher. If the weight average molecular weight is more than 10,000, the heat resistance is excellent, and if it is less than 500,000, the viscosity during melting is low and the adhesion becomes higher.

[0094] Components other than resin in solid adhesives

[0095] The solid adhesive may contain fillers and additives as components other than the resin component as needed within a range that does not hinder the purpose of the present invention.

[0096] Examples of the filler include inorganic fillers and organic fillers (resin powders).

[0097] Examples of the inorganic filler include spherical fused silica, metal powders such as iron, silica sand, talc, calcium carbonate, mica, acid clay, diatomaceous earth, kaolin, quartz, titanium oxide, silicon dioxide, phenolic resin microspheres, and glass balls.

[0098] When a filler is contained, the content of the filler in 100% by volume of the total solid adhesive is preferably 50% by volume or less, more preferably 30% by volume or less, further preferably 20% by volume or less, and most preferably 10% by volume or less.

[0099] The filler content (volume %) was determined from the charge amount at 25° C. Specifically, the mass % relative to the filler was calculated by the following (Formula 1) based on the specific gravity of components other than the filler and the apparent specific gravity of the filler.

[0100] (Formula 1)

[0101] X=(MF / DF)÷(MF / DF+(100-MF) / DR)×100%

[0102] In (Formula 1),

[0103] X: filler content (volume %)

[0104] MF: Filler addition amount (mass %)

[0105] DR: specific gravity of the resin component after curing

[0106] DF: apparent specific gravity of filler.

[0107] Examples of the additives include defoaming agents, coupling agents such as silane coupling agents, and pigments, and these may be contained alone or in combination of two or more.

[0108] The content of the additive in the solid bonding agent is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less.

[0109] The content of the resin component in the solid adhesive is preferably 10% by mass or more, more preferably 20% by mass or more, further preferably 30% by mass or more, and even more preferably 50% by mass or more. In one embodiment, it is 80% by mass or more, in another embodiment, it is 90% by mass or more, and in yet another embodiment, it is 99% by mass or more.

[0110] Method for manufacturing solid adhesive

[0111] The method for producing the solid adhesive is not particularly limited. For example, it can be obtained by heating a monomer or oligomer of a bifunctional epoxy compound to polymerize it. A solvent may be added during polymerization to reduce viscosity and facilitate stirring. If a solvent is added, it must be removed. The solid adhesive can be obtained by drying on a release film, polymerizing, or both.

[0112] Examples of the additives include viscosity modifiers, inorganic fillers, organic fillers (resin powders), defoamers, coupling agents such as silane coupling agents, and pigments, and these may be used alone or in combination of two or more.

[0113] As the viscosity modifier, for example, a reactive diluent or the like can be used.

[0114] Examples of the inorganic filler include spherical fused silica, metal powders such as iron, silica sand, talc, calcium carbonate, mica, acid clay, diatomaceous earth, kaolin, quartz, titanium oxide, silicon dioxide, phenolic resin microspheres, and glass balls.

[0115] The solid adhesive thus obtained has a low content of unreacted monomers and terminal epoxy groups or contains substantially no such monomers, and therefore has excellent storage stability and can be stored for a long period of time at room temperature.

[0116] The solid adhesive's form is not particularly limited, but it preferably has any shape selected from the group consisting of a film, a rod, pellets, and a powder. In particular, it is preferred that at least one side of the outer shape be 5 mm or less, more preferably 3 mm or less, even more preferably 1 mm or less, even more preferably 0.5 mm or less, and most preferably 0.3 mm or less. If the size falls within this range, it can be sandwiched between substrates A and B and efficiently spread across the bonding surface through heating and pressurization, resulting in high bonding strength.

[0117] The solid adhesive may have viscosity within a range that does not impair the adhesive strength and heat resistance. In this case, the solid adhesive is temporarily fixed to the substrate in the laminate preparation step.

[0118] <Joining process>

[0119] In the bonding step, the laminate is heated and pressurized to melt the solid bonding agent, and then the temperature is lowered to solidify the solid bonding agent, thereby bonding the substrates A and B.

[0120] The temperature during heating and pressurizing is preferably 100 to 400° C., more preferably 120 to 350° C., and even more preferably 150 to 300° C. Heating at 100 to 400° C. allows the solid adhesive to efficiently deform and melt, effectively wetting and spreading on the bonding surface, thereby achieving high bonding strength.

[0121] The amorphous thermoplastic resin contained in the solid adhesive has low cohesive force and hydroxyl groups, so it interacts strongly with the base material and can bond dissimilar materials with higher adhesive strength than conventional crystalline hot melt adhesives.

[0122] The bonding of the substrates A and B utilizes the phase change (solid-liquid-solid) of the solid adhesive without chemical reaction, and thus can be completed in a shorter time than with conventional thermosetting epoxy resins.

[0123] [Method for Manufacturing a Joined Body_Embodiment 2]

[0124] The manufacturing method of the joint body of this embodiment is a manufacturing method of the joint body formed by sequentially joining a substrate A, a solid adhesive and a substrate B, wherein the substrate A is a joined component having a joined portion, the solid adhesive contains an amorphous thermoplastic resin, the amorphous thermoplastic resin is at least one selected from thermoplastic epoxy resins and phenoxy resins, and the substrate B is a joining component having a joining portion that is joined with the joined portion of the joined component; or a manufacturing method of the joint body formed by sequentially joining a substrate A, a solid adhesive and a substrate B, wherein the substrate A is a joining component having a joining portion that is joined with the joined portion of the joined component, the solid adhesive contains an amorphous thermoplastic resin, the amorphous thermoplastic resin is at least one selected from thermoplastic epoxy resins and phenoxy resins, and the substrate B is the joined component. The manufacturing method comprises a first joining step and a second joining step. The first joining step comprises: in a state where the solid adhesive is in surface contact with the substrate A, the solid adhesive is melted and then solidified, thereby joining the substrate A and the solid adhesive; the second joining step comprises: in a state where the solid adhesive already joined to the substrate A is in surface contact with the substrate B, the solid adhesive is melted and then solidified, thereby joining the substrate A and the substrate B.

[0125] The base material of the fitted member having the fitted portion is preferably made of metal or resin, and the base material of the fitting member having the fitting portion is preferably made of metal. Examples of the metal and resin include the same metals and resins as those in the first embodiment.

[0126] According to this manufacturing method, the bonding of substrates A and B utilizes the phase transition (solid-liquid-solid) of a solid adhesive comprising an amorphous thermoplastic resin. This amorphous thermoplastic resin is at least one selected from thermoplastic epoxy resins and phenoxy resins. This non-chemically reactive resin allows for faster bonding and a longer open time than conventional thermosetting epoxy resins. Furthermore, thermoplastic epoxy resins and phenoxy resins, due to their low cohesive strength and the presence of hydroxyl groups within the resins, exhibit strong interactions with the substrates, enabling the bonding of dissimilar materials with greater strength than conventional crystalline hot-melt adhesives.

[0127] In addition, in this manufacturing method, the bonding process is divided into a first bonding process and a second bonding process. By separating the processes, heating and bonding can be performed at a temperature suitable for the bonding interface, thereby producing a bonded body with excellent bonding properties. In addition, compared to the case where the processes are not separated, heating temperature control is also easier. Moreover, by pre-bonding a solid bonding agent on substrate A, substrates A and B can be bonded with high precision, which can prevent deviation in the bonding area.

[0128] <First Joining Step>

[0129] The first bonding step is a step of bonding the base material A and the solid bonding agent to each other by melting the solid bonding agent and then solidifying the solid bonding agent while the solid bonding agent is in surface contact with the base material A.

[0130] In the first bonding step, by bonding the base material A to the solid bonding agent in advance, the base material A and the base material B can be bonded with high precision.

[0131] In this specification, "cured" means solid at room temperature, that is, having no fluidity in an unpressurized state at 23° C. However, the solid adhesive after the first bonding step may also have viscosity.

[0132] The method for melting the solid adhesive may be at least one method selected from the group consisting of contact heating, warm air heating, hot pressing, hot plate welding, infrared heating, ultrasonic welding, vibration welding, and high-frequency induction welding. Among these, infrared heating is preferred due to ease of manufacturing and shortened bonding process.

[0133] When the solid adhesive is melted by heating, the surface of the substrate A joining the solid adhesive is preferably heated to 100 to 300°C to melt the adhesive, more preferably 120 to 250°C, and even more preferably 150 to 220°C. Heating at 100 to 300°C allows the solid adhesive to efficiently deform and melt, effectively wetting and spreading on the joining surface, thereby achieving high bonding strength.

[0134] Methods for solidifying the molten solid adhesive include natural cooling at room temperature or natural cooling using a cooling device. It should be noted that "room temperature" refers to a typical room temperature within the range of 5 to 30°C. Natural cooling at room temperature is preferred from the perspective of ease of production.

[0135] (Solid adhesive)

[0136] The solid adhesive is the same as that in the first embodiment, but the solid adhesive in this embodiment is preferably a film. In this disclosure, a film refers to a sheet having a thickness of 10 μm to 3 mm.

[0137] Membrane Morphology

[0138] From the perspective of obtaining a bonded body with excellent bondability in a short bonding process time, the thickness of the film is preferably 1 mm or less, more preferably 0.5 mm or less, further preferably 0.3 mm or less, further preferably 0.2 mm or less, and most preferably 0.1 mm or less.

[0139] When the size falls within this range, the material can be sandwiched between substrates A and B and efficiently expanded on the bonding surface by heating, pressurization, etc., thereby obtaining a high bonding strength.

[0140] The film may be a single layer or a laminate composed of multiple layers, but is preferably a single layer from the viewpoint of ease of production and improvement of bonding strength.

[0141] The film may have adhesiveness within a range that does not hinder the bonding force and heat resistance.

[0142] 《Method for manufacturing membrane》

[0143] The method for producing the film is not particularly limited. For example, a resin composition can be obtained by heating a bifunctional epoxy compound monomer or oligomer to polymerize it, adding a solvent to the obtained resin composition as needed, applying it to a release film, etc., curing and drying it, and applying pressure as needed to obtain a film.

[0144] <Second Joining Step>

[0145] The second bonding step is a step of bonding the substrates A and B by melting and then solidifying the solid bonding agent bonded to the substrates A while the solid bonding agent is in surface contact with the substrates B.

[0146] To achieve high bonding strength, in the second bonding step, heating is preferably performed at a temperature above the melting point of at least one of the substrate B and the solid bonding agent to melt the solid bonding agent and then solidify it. Heating at a temperature above the melting point of at least one of the substrate B and the film allows the film and substrate to become compatible, making it easier to achieve stronger bonding strength.

[0147] The method for melting the solid adhesive may be at least one method selected from the group consisting of contact heating, warm air heating, hot pressing, infrared heating, hot plate welding, ultrasonic welding, vibration welding, and high-frequency induction welding. Of these, hot pressing, ultrasonic welding, and high-frequency induction welding are preferred.

[0148] The conditions for thermal assembly are not particularly limited.

[0149] For example, the temperature is preferably 100 to 400° C., more preferably 120 to 350° C., and even more preferably 150 to 300° C. Heating at 100 to 400° C. allows the solid adhesive to efficiently deform and melt, effectively wetting and spreading on the bonding surfaces, thereby achieving high bonding strength.

[0150] The conditions for high-frequency induction welding are not particularly limited.

[0151] For example, the transmission frequency is preferably 0.1 to 3 MHz, more preferably 0.5 to 2 MHz.

[0152] From the viewpoint of adhesiveness and appearance, the high-frequency application time is preferably 0.1 to 120 seconds, more preferably 1 to 60 seconds.

[0153] When applying pressure to substrates A and B while applying high frequency, the applied pressure is preferably 0.01 to 20 MPa, more preferably 0.1 to 10 MPa, and even more preferably 0.2 to 5 MPa. Within this pressure range, the solid adhesive efficiently deforms, effectively wetting and spreading on the bonding surface, thereby achieving high bonding strength.

[0154] The conditions for high-frequency induction welding are not particularly limited.

[0155] For example, the output power may be in the range of 100 to 10,000 W.

[0156] As described above, the bonding of substrates A and B utilizes the phase change (solid-liquid-solid) of the solid adhesive without chemical reaction, and thus can be completed in a shorter time than with conventional thermosetting epoxy resins.

[0157] [Joint]

[0158] The conjugate of the present invention can be Figure 1The solid rod joint is shown, and can also be Figure 2 Shown is a hollow tubular joint. In addition, it can also be a solid rod and a hollow tubular joint.

[0159] Figure 1 、 2 The bonded body 1 shown is formed by bonding a substrate A and a substrate B together with the aid of a bonding layer 2. The substrate A is a bonded component 3 having a bonded portion, and the substrate B is a bonding component 4 having a bonding portion 41. The bonding portion 41 is bonded with the bonded portion of the bonded component. The bonding layer 2 is formed by solidifying a solid bonding agent containing an amorphous thermoplastic resin after melting. The amorphous thermoplastic resin is at least one selected from thermoplastic epoxy resins and phenoxy resins.

[0160] Joint body of the present invention, even the joint body of heterogeneous materials, also shows excellent bond strength.For bond strength, except the intensity of the interface interaction that plays a role between bonding layer and base material A and between bonding layer and base material B, also be subject to the thickness of bonding layer, the molecular weight of the polymer that constitutes solid bonding agent, chemical structure, mechanical property, the impact of multiple factors such as viscoelasticity, therefore, joint body of the present invention shows the detailed mechanism of excellent bond strength still unclear, but infer that main reason is that the cohesive force in the amorphous thermoplastic resin that constitutes bonding layer 2 is low, and there is hydroxyl in resin, at the interface of bonding layer and base material A and bonding layer and base material B, chemical bond, intermolecular force such as hydrogen bond, van der Waals force are formed.But, in above-mentioned joint body, the state or characteristic of the described interface of described joint body are the extremely thin chemical structure below nanometer level, are difficult to analyze, under current state of the art, determine mechanism, so that it is impossible or impractical to distinguish and express with the technology that does not use solid bonding agent.

[0161] The joined body of the present invention in which the joining layer is formed of a thermoplastic resin has excellent recyclability and repairability, and can be easily disassembled into the base material A and the base material B by heating the joined body.

[0162] The base material of the fitted member having the fitted portion is preferably made of metal or resin, and the base material of the fitting member having the fitting portion is preferably made of metal.

[0163] Examples of metals include aluminum, iron, titanium, magnesium, stainless steel, and copper. Among these, aluminum is particularly preferred due to its lightness and ease of processing. It should be noted that in this disclosure, the term "aluminum" is used to encompass aluminum and its alloys. Similarly, iron, titanium, magnesium, and copper are also used to encompass their individual elements and their alloys.

[0164] The resin is not particularly limited and may be a common synthetic resin. Examples include polycarbonate resins, polyester resins, polybutylene terephthalate resins, polyetherimide resins, and other resins used in automobile parts. Examples include carbon fiber reinforced resins (CFRP) and glass fiber reinforced resins (GFRP), such as sheet molding compounds (SMC) and bulk molding compounds (BMC) using carbon fibers, and other press molded products.

[0165] By subjecting the substrates A and B to pretreatments suitable for the respective substrates, high adhesive strength may be obtained.

[0166] As pre-treatment, the pre-treatment that the surface of base material is cleaned or the pre-treatment that the surface is given concavoconvex can be enumerated.Specifically, degreasing, UV ozone treatment, sandblasting, grinding treatment, plasma treatment, corona discharge treatment, laser treatment, etching treatment, flame treatment etc. can be enumerated.Pre-treatment can be only 1 kind, also can implement 2 or more kinds.As the concrete method of these pre-treatments, known method can be used.

[0167] The degreasing treatment is a method of removing dirt such as grease on the surface of the substrate by dissolving it with an organic solvent such as acetone or toluene.

[0168] UV ozone treatment is a method for cleaning or modifying surfaces using the energy of short-wavelength ultraviolet light emitted by a low-pressure mercury lamp and the power of ozone (O3) generated by it. In the case of glass, it is a surface cleaning method for removing organic impurities from the surface. Cleaning and surface modification equipment using low-pressure mercury lamps is typically referred to as a "UV ozone cleaner," "UV cleaning equipment," or "UV surface modification equipment."

[0169] Examples of the blasting treatment include wet blasting, shot blasting, and sandblasting. Among these, wet blasting is preferred because it can produce a denser surface than dry blasting.

[0170] Examples of the polishing treatment include polishing with a polishing cloth, roller polishing with a polishing paper (sandpaper), and electrolytic polishing.

[0171] The above-mentioned plasma treatment refers to using a high-voltage power supply and a rod to produce a plasma beam, which collides with the surface of the raw material to excite the molecules and make them functional. Examples include atmospheric pressure plasma treatment methods that can impart hydroxyl groups and polar groups to the surface of the raw material.

[0172] The corona discharge treatment is a method for modifying the surface of a polymer film, in which electrons released from an electrode cut the main chain and side chains of the polymer surface layer to generate free radicals, which serve as starting points for generating hydroxyl groups and polar groups on the surface.

[0173] The laser treatment is a technique for improving surface properties by rapidly heating and cooling only the surface of a substrate by laser irradiation, and is an effective method for roughening the surface. Known laser treatment techniques can be used.

[0174] Examples of the etching process include chemical etching processes such as an alkali method, a phosphoric acid-sulfuric acid method, a fluoride method, a chromic acid-sulfuric acid method, and a ferric chloride method, and electrochemical etching processes such as an electrolytic etching method.

[0175] The flame treatment is a method of converting oxygen in the air into plasma by burning a mixture of combustion gas and air, thereby applying oxygen plasma to the treatment target object to achieve surface hydrophilization. Example

[0176] Next, specific examples of the present invention will be described, but the present invention is not particularly limited to these examples. In the following examples, substrate A and substrate B are collectively referred to as bonding substrates.

[0177] <Bonding Base Material>

[0178] The following bonding substrates were used.

[0179] Substrate A:

[0180] Iron: A solid S45C rod with an outer diameter of 20 mm and a length of 140 mm was used as the test piece. The mating portion was sandblasted.

[0181] Aluminum: A solid A6061-T6 bar with an outer diameter of 20 mm and a length of 140 mm was used as the test piece. The mating portion was sandblasted.

[0182] Substrate B: A S35C hollow tube with an inner diameter of 19 mm, a thickness of 4.9 mm, and a length of 140 mm was used as the test piece. The inner diameter portion was wiped with methyl ethyl ketone for degreasing before use.

[0183] <Weight Average Molecular Weight, Heat of Fusion, and Epoxy Equivalent of Thermoplastic Epoxy Resins and Phenoxy Resins>

[0184] The weight average molecular weight, heat of fusion, and epoxy equivalent of the solid adhesive were determined as follows.

[0185] (weight average molecular weight)

[0186] The thermoplastic epoxy resin and the phenoxy resin were dissolved in tetrahydrofuran, and the results were measured under the following conditions using Prominence 501 (manufactured by Showa Kagaku Co., Ltd., Detector: Shodex (registered trademark) RI-501 (manufactured by Showa Denko K.K.)).

[0187] Column: LF-804 manufactured by Showa Denko K.K. × 2

[0188] Column temperature: 40°C

[0189] Sample: 0.4 mass% tetrahydrofuran solution of resin

[0190] Flow rate: 1ml / min

[0191] Eluent: tetrahydrofuran

[0192] Calibration method: Conversion based on standard polystyrene

[0193] (Heat of Fusion)

[0194] 2-10 mg of a thermoplastic epoxy resin and a phenoxy resin were weighed and placed in an aluminum pan. The temperature was then raised from 23°C to 200°C at 10°C / min using a DSC (DSC8231 manufactured by Rigaku Co., Ltd.) to obtain a DSC curve. The heat of fusion was calculated from the endothermic peak area during melting on the DSC curve and the weighed value.

[0195] (Epoxy equivalent)

[0196] The values were measured according to JIS K-7236: 2001 and converted to resin solids. In the case of a simple mixture without reaction, the values were calculated from the epoxy equivalent and content.

[0197] <Example 1>

[0198] (Solid adhesive P-1)

[0199] In a reaction apparatus equipped with a stirrer, reflux cooler, gas inlet tube, and thermometer, 1.0 equivalent (203 g) of jER (registered trademark) 1007 (a bisphenol A-type epoxy resin manufactured by Mitsubishi Chemical Corporation, with a weight-average molecular weight of 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 were added. The mixture was heated to 100°C while stirring under a nitrogen atmosphere. Dissolution was visually confirmed, and the mixture was cooled to 40°C to obtain a solid. Non-stick fluororesin films (Nitofluon (registered trademark) No. 900UL, manufactured by Nitto Denko Corporation) were placed on the upper and lower plates of the press. The solid was placed on the non-stick fluororesin film on the lower plate. The press was then heated to 160°C and the resin composition was heat-compressed for 2 hours to obtain a resin composition having a solid content of approximately 20% by mass. The solvent was removed to obtain a film-like solid adhesive (P-1) having a solid content of 100% by mass and a thickness of 100 μm. The weight average molecular weight was approximately 37,000. The epoxy equivalent was above the detection limit. No melting heat peak was detected by DSC.

[0200] (joint)

[0201] The following two types of joints were prepared. For open time evaluation, the joints were prepared in the same manner as described in the following "Iron·Iron" except that a solid adhesive was placed on the iron substrate (substrate A) and allowed to stand for 3 days before being embedded in the iron substrate (substrate B).

[0202] Iron Iron

[0203] The solid adhesive P-1, cut to a width of 70 mm, was wound around the iron substrate A. Then, the substrate A was inserted into the inner diameter of the iron substrate B, heated to 350°C. The substrates overlapped by 65 mm. The substrates were then cooled naturally to obtain a bonded product. The solid adhesive P-1 was applied to cover the entire overlapping area between the substrates. In other words, the unbonded laminate was prepared with the solid adhesive sandwiched between substrates A and B, without direct contact.

[0204] <<Aluminum·Iron>> A joint body was obtained in the same manner as the above-mentioned <<Iron·Iron>> joint body except that the above-mentioned aluminum substrate was used as substrate A.

[0205] <Example 2>

[0206] (Solid adhesive P-2)

[0207] In a reaction apparatus equipped with a stirrer, reflux cooler, gas inlet tube, and thermometer, 20 g of Enote (registered trademark) YP-50S (phenoxy resin, weight-average molecular weight approximately 50,000, manufactured by Nippon Steel Chemical & Material Co., Ltd.) and 80 g of cyclohexanone were added. The mixture was heated to 60°C while stirring, visually confirmed for dissolution, and then cooled to 40°C to obtain a resin composition having a solid content of 20% by mass. The solvent was removed from the composition to obtain a solid. Non-stick fluororesin films (Nito Fluon (registered trademark) No. 900UL, manufactured by Nitto Denko Corporation) were placed on the upper and lower plates of the press. The solid was placed on the non-stick fluororesin film on the lower plate. The press was then heated to 160°C and the resin composition was heat-compressed for 2 hours to obtain a film-like solid adhesive (P-2) having a solid content of 100% by mass and a thickness of 100 μm. The weight average molecular weight was 50,000, the epoxy equivalent was above the detection limit, and no melting heat peak was detected by DSC.

[0208] (joint)

[0209] Two types of joined bodies and a joined body for open time evaluation were prepared in the same manner as in Example 1, except that P-2 was used as the solid joining agent.

[0210] <Example 3>

[0211] (Solid adhesive P-3)

[0212] The resin composition P-2 was mixed with a crystalline epoxy resin YSLV-80XY (manufactured by Nippon Steel Chemical & Material Co., Ltd.) at a mass ratio of 98:2 to obtain a solid adhesive (P-3). The adhesive had a weight-average molecular weight of 36,000, an epoxy equivalent of 9600 g / eq, and a heat of fusion of 2 J / g.

[0213] (joint)

[0214] Two types of joined bodies and a joined body for open time evaluation were produced in the same manner as in Example 1, except that P-3 was used as the solid joining agent.

[0215] <Example 4>

[0216] (Solid adhesive P-4)

[0217] The resin composition P-2 was mixed with a crystalline epoxy resin YSLV-80XY (manufactured by Nippon Steel Chemical & Material Co., Ltd.) at a mass ratio of 94:6 to obtain a solid adhesive (P-4). The adhesive had a weight-average molecular weight of 35,000, an epoxy equivalent of 2100 g / eq, and a heat of fusion of 4 J / g.

[0218] (joint)

[0219] Two types of joined bodies and a joined body for open time evaluation were prepared in the same manner as in Example 1, except that P-4 was used as the solid joining agent.

[0220] <Example 5>

[0221] (Solid adhesive P-5)

[0222] The resin composition P-2 and crystalline epoxy resin YSLV-80XY (manufactured by Nippon Steel Chemical & Material Co., Ltd.) were mixed at a mass ratio of 89 to 11 to obtain a solid adhesive (P-5). The adhesive had a weight-average molecular weight of 33,000, an epoxy equivalent of 1745 g / eq, and a heat of fusion of 11 J / g.

[0223] (joint)

[0224] Two types of joined bodies and a joined body for open time evaluation were prepared in the same manner as in Example 1, except that P-5 was used as the solid joining agent.

[0225] <Example 6>

[0226] (Solid adhesive P-6)

[0227] A reaction apparatus equipped with a stirrer, reflux cooler, gas inlet tube, and thermometer was charged with 1.0 equivalent (203 g) of jER (registered trademark) 1007 (manufactured by Mitsubishi Chemical Corporation, bisphenol A-type epoxy resin, molecular weight approximately 4060), 0.6 equivalent (12.5 g) of bisphenol S (molecular weight 250), 2.4 g of triphenylphosphine, and 1,000 g of methyl ethyl ketone. The mixture was heated to 100°C while stirring under a nitrogen atmosphere. Dissolution was visually confirmed, and the mixture was cooled to 40°C to obtain a resin composition having a solid content of approximately 20% by mass. The solvent was removed from the mixture to obtain a solid. Non-stick fluororesin films (Nitofluon (registered trademark) No. 900UL, manufactured by Nitto Denko Corporation) were placed on the upper and lower plates of the press. The solid was placed on the non-stick fluororesin film on the lower plate. The press was then heated to 160°C and the resin composition was heat-compressed for 2 hours to produce a film-like solid adhesive (P-6) with a solids content of 100% by mass and a thickness of 100 μm. The weight-average molecular weight was approximately 30,000, and the epoxy equivalent was above the detection limit. No heat of fusion peak was detected by DSC.

[0228] (joint)

[0229] Regarding the method for producing the bonded bodies, two bonded bodies and a bonded body for open time evaluation were produced in the same manner as in Example 1, except that P-6 was used as the solid bonding agent.

[0230] <Example 7>

[0231] When making a joint body, the above-mentioned solid bonding agent P-1 is arranged on the substrate A, and the film is melted by heating to 200°C, and then naturally cooled at room temperature for 1 minute to solidify the film. After the substrate A is joined with the solid bonding material, it is joined with the substrate B. Except for this, two joint bodies and a joint body for open time evaluation are made in the same manner as Example 1.

[0232] <Comparative Example 1>

[0233] (Solid Adhesive Q-1)

[0234] Two liquids of thermosetting liquid epoxy adhesive E-250 (manufactured by Konishi Co., Ltd., a two-part type consisting of a bisphenol-type epoxy resin and an amine curing agent) were mixed and applied to a release film. After curing at 100°C for 1 hour, the adhesive was cooled and peeled from the release film to obtain a 100 μm thick film-like solid adhesive (Q-1). No heat of fusion peak was detected by DSC. Since the adhesive was insoluble in the solvent, the epoxy equivalent and weight-average molecular weight could not be determined.

[0235] (joint)

[0236] Two types of joined bodies and a joined body for open time evaluation were prepared in the same manner as in Example 1, except that Q-1 was used as the solid joining agent.

[0237] <Comparative Example 2>

[0238] (Solid Adhesive Q-2)

[0239] An amorphous polycarbonate film (Upperlon (registered trademark) FE2000, manufactured by Mitsubishi Engineering-Plastics Corporation, thickness 100 μm) was used as the solid adhesive Q-2. No melting heat peak was detected in DSC.

[0240] (joint)

[0241] Two types of joined bodies and a joined body for open time evaluation were prepared in the same manner as in Example 1, except that Q-2 was used as the solid joining agent.

[0242] <Comparative Example 3>

[0243] (Solid Adhesive Q-3)

[0244] Crystalline epoxy resin YSLV-80XY (manufactured by Nippon Steel Chemical & Material Co., Ltd.) was used as the solid adhesive (Q-3). Its epoxy equivalent was 192 g / eq, its weight-average molecular weight was 340, and its heat of fusion was 70 J / g.

[0245] (joint)

[0246] Two types of joined bodies and a joined body for open time evaluation were prepared in the same manner as in Example 1, except that Q-3 was used as the solid joining agent.

[0247] <Comparative Example 4>

[0248] (joint)

[0249] Two liquids of thermosetting liquid epoxy adhesive E-250 (manufactured by Konishi Co., Ltd., a two-liquid type of bisphenol-type epoxy resin and amine curing agent) were mixed and applied respectively on two substrates A similar to those in Example 1 above. Within 1 minute, the mixture was inserted into a substrate B heated to 350°C and cooled to room temperature to produce two bonded bodies.

[0250] A joined body for open time evaluation was prepared in the same manner as in Example 1 except that the thermosetting liquid epoxy adhesive E-250 was applied to the substrate A and then left to stand for 3 days before joining.

[0251] <Comparative Example 5>

[0252] 1.0 equivalent (203 g) of jER (registered trademark) 1007 (manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin, weight average molecular weight of about 10,000), 1.0 equivalent (12.5 g) of bisphenol S, 2.4 g of triphenylphosphine and 1,000 g of methyl ethyl ketone were added to a flask and stirred at room temperature to obtain a liquid resin composition having a solid content of about 20% by mass. The liquid resin composition was sprayed onto two substrates A similar to those in Example 1, dried at room temperature for 30 minutes, and then allowed to stand in an oven at 160°C for 2 hours, thereby forming a solid thermoplastic epoxy resin polymer coating with a thickness of 100 μm on the surface of substrate A. The weight average molecular weight of the coating was about 40,000. The epoxy equivalent was above the detection limit. No melting heat peak was detected in DSC.

[0253] (joint)

[0254] Two types of joined bodies were produced by the same operation as in Example 1, except that the substrate A having the coating layer was inserted into the substrate B heated to 350°C.

[0255] For open time evaluation, a joined body for open time evaluation was prepared in the same manner as in Example 1 except that a thermoplastic epoxy resin polymer coating was formed on the surface of substrate A, the coating was allowed to stand for 3 days, and then joined to substrate B.

[0256] <Comparative Example 6>

[0257] In a reaction apparatus equipped with a stirrer, a reflux cooler, a gas inlet pipe and a thermometer, 20 g of FUNOTOTO (registered trademark) YP-50S (manufactured by Nippon Steel Chemical & Material Co., Ltd., a phenoxy resin with a weight-average molecular weight of about 50,000) and 80 g of cyclohexanone were added, and the temperature was raised to 60°C while stirring. Dissolution was visually confirmed, and the mixture was cooled to 40°C to obtain a liquid resin composition with a solid content of 20% by mass. The liquid resin composition was applied to the three substrates B similar to those in Example 1 above, and the mixture was allowed to stand in an oven at 70°C for 30 minutes, thereby forming a phenoxy resin coating with a thickness of 100 μm on the surface of the substrate B. The weight-average molecular weight of the coating was about 50,000. The epoxy equivalent was above the detection limit. No melting heat peak was detected in DSC.

[0258] (joint)

[0259] Two types of joined bodies were produced by performing the same operation as in Example 1, except that the substrate A was directly placed on the substrate B having the phenoxy resin coating layer.

[0260] Furthermore, for open time evaluation, a joined body for open time evaluation was prepared in the same manner as in Example 1 except that a phenoxy resin coating was formed on the surface of substrate B, the substrate was allowed to stand for 3 days, and then laminated with substrate A.

[0261] <Comparative Example 7>

[0262] (joint)

[0263] Two bonded bodies and a bonded body for open time evaluation were prepared in the same manner as in Example 1, except that crystalline polyamide hot melt adhesive film NT-120 (manufactured by Nippon Matei Co., Ltd., thickness 100 μm) was used as the solid bonding agent. The heat of fusion was 60 J / g.

[0264] [Shear Adhesion]

[0265] The bonded bodies obtained in Examples 1 to 7 and Comparative Examples 1 to 7 were allowed to stand at a measurement temperature (23°C or 80°C) for at least 30 minutes. The bonded bodies were then subjected to a tensile strength test in a 23°C atmosphere using a tensile testing machine (Universal Testing Machine Autograph "AG-X plus" (manufactured by Shimadzu Corporation); load cell 10 kN, tensile speed 10 mm / min) to measure the bond strength. The measurement results are shown in Tables 1-1 and 1-2.

[0266] [Joining process time]

[0267] The bonding process time is measured as follows.

[0268] The time from the start point to the end point was measured, with the time when at least one substrate constituting the bonded body came into contact with the bonding agent being the starting point and the time when the bonded body was finished being the end point. Regarding the heating-bonding time, the heating-bonding time of each of the two bonded bodies was averaged. The measurement results are shown in Tables 1-1 and 1-2.

[0269] [Recyclability]

[0270] After heating the bonded body in an oven at 200°C for 10 minutes, it was determined whether it could be easily separated with a force of 1 N or less. If it could be separated, it was evaluated as good (A); if it could not be separated, it was evaluated as unsatisfactory (B).

[0271] [Restorability]

[0272] In each of the iron and iron test pieces (a layer of bonding solids remaining on the surface of either substrate A or B, or both) whose bonding surfaces had broken after the tensile strength test at 23°C, substrate B was heated to 350°C and inserted into substrate A, thereby producing a bonded body in the same manner as in Example 1. A repaired bonded body was thus obtained. The tensile bonding strength of the repaired bonded body at 23°C was measured in the same manner as the above test method. If it was 80% or more of the initial shear bonding strength, it was evaluated as good (A); if it was less than 80%, it was evaluated as unsatisfactory (B). The evaluation results are shown in Tables 1-1 and 1-2.

[0273] [Opening hours evaluation]

[0274] The above-described tensile shear adhesive strength test was conducted at 23°C using the bonded article for open time evaluation. A shear adhesive strength of 80% or greater compared to the test pieces prepared using the methods of the above-described Examples and Comparative Examples was evaluated as good (A), while a strength of less than 80% was evaluated as unacceptable (B). An open time evaluation of good (A) indicates a long open time and excellent convenience.

[0275] The evaluation results are shown in Table 1-1 and Table 1-2.

[0276]

[0277]

[0278] Industrial applicability

[0279] The bonded body obtained by the manufacturing method of the present invention can be used as, for example, door side panels, engine hoods, tailgates, steering racks, A-pillars, B-pillars, C-pillars, D-pillars, crash boxes, power control unit (PCU) housings, electric compressor components (inner wall portions, air intakes, exhaust control valve (ECV) insertion portions, mounting boss portions, etc.), lithium-ion battery (LIB) spacers, battery cases, automotive parts such as LED headlights, smartphones, laptop computers, tablet computers, smart watches, large liquid crystal televisions (LCD-TVs), and structures for outdoor LED lighting, but is not particularly limited to these exemplified uses.

[0280] Explanation of symbols

[0281] 1 Conjugate

[0282] 2 Adhesive layer

[0283] 3. Mated parts

[0284] 4 Fitting parts

[0285] 41 Chimera Department

Claims

1. A method for producing a bonded body, comprising a pre-bonding step and a bonding step. The pre-joining step comprises: sequentially arranging a substrate A, a solid bonding agent, and a substrate B to prepare a laminate, wherein the substrate A is a member to be joined having a portion to be joined, the solid bonding agent comprises an amorphous thermoplastic resin, the amorphous thermoplastic resin being at least one selected from a thermoplastic epoxy resin and a phenoxy resin, and the substrate B is a joining member having a joining portion to be joined with the joining portion of the member to be joined; The bonding step includes heating and pressurizing the laminate to melt the solid bonding agent, thereby bonding the substrate A and the substrate B; The amorphous thermoplastic resin has an epoxy equivalent of 1,600 or more or contains no epoxy group, and has a heat of fusion of 15 J / g or less. 2 . The method for manufacturing a joined body according to claim 1 , wherein the engaged member is made of metal or resin, and the engaging member is made of metal. 3 . The method for producing a joined body according to claim 1 , wherein the fitting portion is heated to 100 to 400° C. for fitting.

4. A method for manufacturing a joined body, comprising: sequentially joining a substrate A, a solid adhesive, and a substrate B, wherein the substrate A is a joined component having a joined portion, the solid adhesive comprises an amorphous thermoplastic resin, the amorphous thermoplastic resin being at least one selected from thermoplastic epoxy resins and phenoxy resins, and the substrate B is a fitting component having a fitting portion that fits with the joined portion of the joined component; or a method for manufacturing a joined body, comprising sequentially joining a substrate A, a solid adhesive, and a substrate B, wherein the substrate A is a fitting component having a fitting portion that fits with the joined portion of the joined component, the solid adhesive comprises an amorphous thermoplastic resin being at least one selected from thermoplastic epoxy resins and phenoxy resins, and the substrate B is the joined component; The method comprises a first bonding step and a second bonding step. The first bonding step comprises: melting the solid bonding agent and then solidifying the solid bonding agent in a state where the solid bonding agent is in surface contact with the substrate A, thereby bonding the substrate A and the solid bonding agent; The second bonding step comprises: melting and then solidifying the solid bonding agent bonded to the substrate A in a state where the solid bonding agent is in surface contact with the substrate B, thereby bonding the substrate A and the substrate B; The amorphous thermoplastic resin has an epoxy equivalent of 1,600 g / eq. or more or contains no epoxy group, and has a heat of fusion of 15 J / g or less. 5 . The method for producing a bonded body according to claim 4 , wherein in the first bonding step, the solid bonding agent is heated to 100 to 300° C. to be melted and then solidified.

6. The method for manufacturing a joint body according to claim 4, wherein in the second joining process, the solid adhesive is melted and then solidified by at least one selected from contact heating, warm air heating, hot pressing, infrared heating, hot plate welding, ultrasonic welding, vibration welding and high-frequency induction welding. 7 . The method for producing a bonded body according to claim 4 , wherein in the second bonding step, the solid bonding agent is melted and then solidified at a heating temperature of 100 to 400° C. and a pressure of 0.01 to 20 MPa. 8 . The method for producing a bonded body according to claim 1 , wherein the solid bonding agent before melting has a film shape.

9. A joined body formed by joining a substrate A and a substrate B via an adhesive layer, wherein the substrate A is a fitted member having a fitted portion, and the substrate B is a fitting member having a fitting portion that fits with the fitted portion of the fitted member; The adhesive layer is formed by placing a solid adhesive comprising an amorphous thermoplastic resin between the substrate A and the substrate B, heating and pressurizing the resin to melt it, and then curing the solid adhesive. The amorphous thermoplastic resin is at least one selected from a thermoplastic epoxy resin and a phenoxy resin, and has an epoxy equivalent of 1,600 or greater and a heat of fusion of 15 J / g or less. 10 . The bonded body according to claim 9 , wherein the heating and pressurizing are performed under the conditions of 100 to 400° C. and 0.01 to 20 MPa.

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