Disassembly method for bonded member and easily-disassembled silicone-based liquid adhesive agent

Abstract

In the present invention, a bonded member is obtained by bonding together a plurality of members, including a member in which at least a portion of a bonding interface is metal, by means of a cured product obtained by curing a curable silicone-based liquid adhesive agent, which contains 25-80 mass% of a hydroxide compound having a decomposition temperature of 180-600ºC and in which the content of a material for generating heat by electromagnetic induction is no more than 3 mass%. The bonded member exhibits sealing properties at room temperature and, moreover, it is possible to easily disassemble the bonded member in a short time and with little consumed energy, even after exposure to high temperatures of approximately 150ºC, by heating the metal portion at the bonding interface of the bonded member by electromagnetic induction, and it is possible to recycle the disassembled member.

Description

Method for dismantling joining components and easily dismantled liquid silicone adhesive

[0001] The present invention relates to a method for dismantling bonded members that use a curable liquid silicone adhesive, which enables easy and rapid collection, repair, and recycling of automobile parts such as automobile electrical components, electrical and electronic products, and an easily dismantled liquid silicone adhesive for use in said method.

[0002] In recent years, recyclability has become increasingly important in various fields due to its environmental friendliness and ability to reduce costs. For recycling purposes, it is necessary to disassemble bonded components into separate parts, even in the automotive, electrical, and electronics industries. However, since bonded components play an important role in preventing the intrusion of external dust and moisture and protecting internal components, they also require reliable sealing performance. Since adhesive sealing provides the best sealing performance, adhesive properties must be maintained even under various conditions (heat resistance, moisture resistance, etc.). Therefore, the cured product is usually strongly adhered to the substrate, making it difficult to remove the bonded components.

[0003] As a method for recycling bonded members using a curable resin composition, for example, Japanese Patent Application Laid-Open No. 2003-026784 (Patent Document 1) proposes softening or liquefying bonded members made using a polyol-based curable composition by heating them to 150 to 200°C, thereby dismantling the bonded members. Japanese Patent Application Laid-Open No. 2002-327163 (Patent Document 2) proposes contacting a halogen-based organic solvent with the bonded portion of a bonded structure using a moisture-curing adhesive primarily composed of a urethane prepolymer to reduce the adhesive strength of the bonded portion, and then peeling and dismantling the constituent members of the bonded structure from the bonded portion. Furthermore, Japanese Patent Application Laid-Open No. 2008-120903 (Patent Document 3) proposes a removable pressure-sensitive adhesive tape that uses an adhesive composed of a vinyl-based monomer mixture primarily composed of alkyl (meth)acrylate, maintaining high normal adhesive strength during bonding, but reducing the adhesive strength by heating when separating or dismantling the bonded portion, allowing for easy separation and dismantling. Japanese Patent No. 6221630 (Patent Document 4) proposes that by incorporating a tackifying resin into an oxyalkylene polymer, the polymer can be reworked, and can be rebonded even after rework, thereby maintaining its sealing performance.

[0004] On the other hand, silicone adhesives and sealants have superior properties such as heat resistance and weather resistance compared to the above organic adhesives, and are therefore widely used in the automotive, electrical and electronics, construction, etc. However, there is a problem in that silicone adhesives and sealants are difficult to decompose even when heated, making them difficult to repair or recycle.

[0005] Masking-type silicone adhesives have been proposed as silicone adhesives that allow for easy disassembly of components and exhibit sealing properties. Masking-type silicone adhesives that do not contain adhesion promoters include silicone adhesives that have been given release properties by adding a release agent to provide releasability to glass and metal. However, when such silicone adhesives are subjected to high temperatures exceeding 200°C, the release agent itself thermally decomposes and loses its effectiveness, and the silicone adhesive bonds to the components due to heat, making disassembly difficult and making recovery and repair difficult.

[0006] Therefore, there is a demand for recyclable bonding members and methods for dismantling them, even in applications where silicone adhesives are used for bonding.

[0007] Japanese Patent Application Publication No. 2003-026784 Japanese Patent Application Publication No. 2002-327163 Japanese Patent Application Publication No. 2008-120903 Japanese Patent No. 6221630 Japanese Patent Application Publication No. 2022-183437 Japanese Patent Application Publication No. 2021-160447

[0008] The present invention has been made in view of the above circumstances, and aims to provide a method for dismantling joined members in which the joined adhesive members are a silicone-based adhesive, and which can be easily recycled in a short time with little energy consumption while maintaining sealing performance at room temperature (23°C±15°C, the same applies hereinafter) and even after exposure to high temperatures of around 150°C, and an easily dismantled liquid silicone-based adhesive to be used in the method for dismantling joined members.

[0009] To achieve the above object, the present inventors proposed a method in their previously filed Japanese Patent Application Laid-Open Publication No. 2022-183437 (Japanese Patent Application No. 2021-090750) (Patent Document 5) in which a specific proportion of aluminum hydroxide, which decomposes at around 160°C, is blended into a curable liquid silicone adhesive, allowing joined adhesive members to maintain their sealing properties even after being exposed to room temperature and even high temperatures of around 150°C, while exposing them to high temperatures of 160°C or higher to reduce the sealing properties and facilitate separation of the members. However, this method requires heating for a long period of several hours using a heating furnace, resulting in a high energy consumption.

[0010] Furthermore, Japanese Patent Application No. 2021-160447 (Patent Document 6) proposed a method for easily dismantling multiple components by irradiating microwaves onto a joint member in which multiple components are joined together with a curable liquid silicone adhesive containing particles that generate heat in response to microwaves and a hydroxide compound whose decomposition temperature is 180 to 600° C. However, this method still requires several minutes, and a shorter dismantling time is desired.

[0011] The present inventors therefore conducted extensive research into bonded components that can be recycled in a short time with less energy consumption, and methods for dismantling the same. As a result, they discovered that, in order to improve the efficiency and energy conservation of the collection, repair, and recycling of automobile parts, electrical and electronic products, etc., a bonded component formed by bonding multiple components, including components where at least a portion of the bonding interface is metal, using a cured product obtained by curing a curable liquid silicone adhesive containing 25 to 80 mass % of a hydroxide compound (particularly a metal hydroxide or metal oxide hydroxide) with a decomposition temperature of 180 to 600°C, and containing 3 mass % or less of a material that generates heat by electromagnetic induction, can maintain sealing properties even after exposure to room temperature and even to high temperatures of around 150°C, and that by heating the metal portion of the bonding interface within the bonded component by electromagnetic induction, the bonded component can be easily dismantled in a short time with little energy consumption, and the dismantled components can be recycled, thereby completing the present invention.

[0012] Accordingly, the present invention provides the following methods for dismantling bonded members and an easily dismantlable liquid silicone adhesive: [1] A method for dismantling bonded members, comprising the step of: providing a bonded member formed by bonding together a plurality of members, including a member at least a portion of which is metal, using a curable liquid silicone adhesive cured to a cured product obtained by curing the curable liquid silicone adhesive, the curable liquid silicone adhesive containing 25 to 80 mass % of a hydroxide compound having a decomposition temperature of 180 to 600°C and containing 3 mass % or less of a material that generates heat upon electromagnetic induction; heating the metal portion of the bonded interface by electromagnetic induction to separate the metal-containing members from among the members; and dismantling the bonded member; [2] The method for dismantling bonded members according to [1], wherein the curable liquid silicone adhesive is a condensation-curing liquid silicone adhesive, an addition-reaction-curing liquid silicone adhesive, or an ultraviolet-curing liquid silicone adhesive. [3] The method for dismantling joined members according to [1] or [2], wherein the hydroxide compound having a decomposition temperature of 180 to 600°C is at least one selected from aluminum hydroxide, magnesium hydroxide, and aluminum oxide hydroxide (boehmite). [4] The method for dismantling joined members according to any one of [1] to [3], wherein the frequency of electromagnetic induction heating is 100 kHz or more and 500 kHz or less. [5] The method for dismantling joined members according to any one of [1] to [4], wherein the joined members are automobile parts or electrical / electronic parts. [6] An easily dismantlable condensation-curing liquid silicone adhesive used in the method for dismantling joined members according to any one of [1] to [5], comprising the following components (A) to (E), and wherein the content of the material that generates heat by electromagnetic induction is 3 mass% or less: (A) a hydroxide compound having a decomposition temperature of 180 to 600°C: an amount that accounts for 25 to 80 mass% of the total adhesive, (B) a linear diorganopolysiloxane having both molecular chain terminals blocked with silicon-bonded hydroxyl groups and / or hydrolyzable silyl groups: 100 parts by mass, (C) a hydrolyzable organosilane compound and / or a partial hydrolysis condensate thereof having three or more silicon-bonded hydrolyzable groups in the molecule: 0.1 to 40 parts by mass, (D) a curing catalyst: 0.001 to 20 parts by mass, and (E) a silane coupling agent: 0.05 to 20 parts by mass.[7] An easily dismantlable addition reaction curable liquid silicone adhesive used in the method for dismantling joined members according to any one of [1] to [5], which contains the following components (A) and (F) to (H), and has an electromagnetic induction heat-generating material content of 3 mass% or less: (A) a hydroxide compound having a decomposition temperature of 180 to 600°C: an amount that accounts for 25 to 80% by mass of the entire adhesive, (F) an alkenyl-containing organopolysiloxane having a silicon-bonded alkenyl group at a molecular chain terminal: 100 parts by mass, (G) an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in the molecule: an amount that provides 0.01 to 3 moles of silicon-bonded hydrogen atoms per mole of silicon-bonded alkenyl groups in component (F), (H) a platinum group metal catalyst: 0.01 to 1,000 ppm, calculated as the mass of platinum group metal atoms, based on the total amount of components (F) and (G), and (I) an adhesion promoter: 0.05 to 20 parts by mass. [8] An easily dismantlable ultraviolet-curable liquid silicone adhesive used in the method for dismantling joined members according to any one of [1] to [5], containing the following components (A), (J), and (K), and having a content of a material that generates heat by electromagnetic induction of 3% by mass or less: (A) a hydroxide compound having a decomposition temperature of 180 to 600°C: 25 to 80% by mass of the total adhesive, (J) an ultraviolet-reactive organopolysiloxane: 100 parts by mass, and (K) a photopolymerization initiator: 0.01 to 10 parts by mass.

[0013] According to the method for dismantling bonded members of the present invention, while maintaining adhesive and / or sealing properties from room temperature to high temperatures of around 150°C, electromagnetic induction heating of the metal portion of the bonded interface indirectly heats the cured product of the adhesive member, the curable liquid silicone adhesive, thereby reducing the adhesive and / or sealing properties, allowing the metal-containing members at the bonded interface to be separated in a short time with little energy, thereby enabling bonded members to be easily dismantled and recycled. The curable liquid silicone adhesive used in this dismantling method is useful as an adhesive or sealing material for bonded parts that require heat resistance and recycling.

[0014] In the present invention, the "heat resistance temperature" of a member to be dismantled means the upper limit of the temperature at which the member does not undergo thermal decomposition or softening when left standing at a specific temperature for one minute.

[0015] 1A and 1B are images of the surface state of the ADC12 substrate observed with a digital microscope before and after electromagnetic induction heating in Example 1 of the present invention.

[0016] The present invention will be described in detail below.

[0017] The method for dismantling bonded members of the present invention includes a step of dismantling a bonded member in which a plurality of members, including members at least a portion of which at the bonding interface is made of metal, are bonded together using a cured product obtained by curing a curable liquid silicone adhesive containing 25 to 80 mass % of a hydroxide compound (particularly a metal hydroxide or a metal oxide hydroxide) having a decomposition temperature of 180 to 600°C and containing 3 mass % or less of a material that generates heat by electromagnetic induction, by heating the metal portion of the bonding interface by electromagnetic induction to separate the metal-containing members from among the members and dismantle the bonded member.

[0018] [Curable Liquid Silicone-Based Adhesive] The curable liquid silicone-based adhesive used in the present invention cures to become an adhesive member that bonds together a plurality of components, including components where at least a portion of the bonding interface is made of metal. The adhesive contains a hydroxide compound (A) with a decomposition temperature of 180 to 600°C, has an electromagnetic induction heat generating material content of 3 mass% or less, and uses a polymer whose main chain comprises a siloxane bond as the base polymer. The curing type is preferably a condensation curing type, an addition reaction curing type, or an ultraviolet curing type.

[0019] [Hydroxylated Compounds Having a Decomposition Temperature of 180 to 600° C.] The hydroxide compounds having a decomposition temperature of 180 to 600° C. are usually preferably metal hydroxides or metal oxide hydroxides, and examples thereof include aluminum hydroxide having a decomposition temperature of around 180° C., magnesium hydroxide having a decomposition temperature of around 300° C., and aluminum hydroxide oxide (boehmite) having a decomposition temperature of around 500° C. The "decomposition temperature" refers to the temperature at which the hydroxide compound begins to decompose and generate water.

[0020] These materials begin to decompose when heated, generating water as a result of the decomposition, which has an anti-flammability effect and has traditionally been used as a flame-retardant material. In the present invention, the water generated by this decomposition is used to generate bubbles in the cured product of the curable liquid silicone adhesive, which reduces the adhesive strength and makes it easy to disassemble the joined components in a short time.

[0021] As the hydroxide compound having a decomposition temperature of 180 to 600°C, particulates having an average particle size of 50 μm or less, preferably 0.5 to 20 μm, are used. If the average particle size is greater than 50 μm, decomposition properties will decrease. The average particle size can be determined as the cumulative weight average value D50 (or median diameter) using a particle size distribution measuring device using a laser light diffraction method or the like.

[0022] The surface of the hydroxide compound may be untreated or may be surface-treated (hydrophobized). When surface treatment is performed, a commonly used treating agent is used, such as a silane coupling agent or a fatty acid. The surface treatment can be carried out by a known method. The amount of treatment is not particularly limited, but is preferably 3% by mass or less (usually 0.1 to 3% by mass), particularly 0.2 to 2% by mass.

[0023] The hydroxide compounds may be used singly or in combination of two or more compounds having different average particle sizes or surface treatment methods.

[0024] The content of the hydroxide compound is 25 to 80% by mass of the entire curable liquid silicone adhesive, preferably 30 to 70% by mass, and more preferably 35 to 65% by mass. If it is less than 25% by mass, decomposition (foaming) of the hydroxide compound will be insufficient and dismantling properties will be reduced, while if it is more than 80% by mass, the viscosity of the composition will increase, making it difficult to mix and discharge during application.

[0025] [Materials that generate heat by electromagnetic induction] Examples of materials that generate heat by electromagnetic induction include metal materials and carbon materials such as carbon fiber and carbon black. Examples of metal materials used in curable liquid silicone adhesives include aluminum powder, iron powder, copper powder, and alloy powders thereof.

[0026] The curable liquid silicone adhesive used in the present invention contains as little material as possible that generates heat by electromagnetic induction, but even if it contains a material that generates heat by electromagnetic induction as a component contained in an optional additive such as a colorant, the amount of this material blended in the curable liquid silicone adhesive should be 3% by mass or less (0 to 3% by mass), and particularly 1% by mass or less (0 to 1% by mass). If it exceeds 3% by mass, dismantling properties will decrease.

[0027] The electromagnetic induction heating used in the heating method of the present invention can heat conductive metal materials and carbon materials (e.g., carbon fiber, graphite, carbon black, etc.). On the other hand, in the present invention, by using electromagnetic induction to heat the bonding interface of the metals used in the bonding members, efficient delamination can be achieved in a short period of time. However, if a material that generates heat by electromagnetic induction is added to the adhesive itself, the electromagnetic induction energy is also used to heat the bonding members (cured adhesive), reducing dismantling properties. Furthermore, when an organic resin is used in the members, heating the bonding members heats the organic resin in contact with the bonding members to a temperature exceeding its heat resistance, causing the organic resin to dissolve or decompose, making the members unsuitable for recycling. Therefore, it is preferable to add as little material that generates heat by electromagnetic induction as possible to the curable liquid silicone adhesive of the present invention (3% by mass or less).

[0028] [Condensation-curable liquid silicone adhesive] The condensation-curable liquid silicone adhesive contains, in addition to the above-mentioned (A) hydroxide compound having a decomposition temperature of 180 to 600°C, (B) a linear diorganopolysiloxane (base polymer) having both molecular chain terminals blocked with silicon-bonded hydroxyl groups and / or hydrolyzable silyl groups, (C) a hydrolyzable organosilane compound having three or more silicon-bonded hydrolyzable groups per molecule and / or a partial hydrolysis condensate thereof (crosslinking agent), (D) a curing catalyst, and (E) a silane coupling agent (adhesion-imparting agent), and is a liquid silicone adhesive that obtains a cured product by utilizing a hydrolysis and condensation reaction caused by moisture (humidity) in the atmosphere at room temperature. The condensation-curing liquid silicone adhesive is preferably an easily dismantlable condensation-curing liquid silicone adhesive containing: (A) a hydroxide compound having a decomposition temperature of 180 to 600°C: in an amount that accounts for 25 to 80 mass% of the total adhesive; (B) 100 parts by mass of a linear diorganopolysiloxane having both molecular chain terminals blocked with silicon-bonded hydroxyl groups and / or hydrolyzable silyl groups; (C) 0.1 to 40 parts by mass of a hydrolyzable organosilane compound and / or a partial hydrolysis condensate thereof having three or more silicon-bonded hydrolyzable groups in the molecule; (D) 0.001 to 20 parts by mass of a curing catalyst; and (E) 0.05 to 20 parts by mass of a silane coupling agent, and the content of the material that generates heat by electromagnetic induction is preferably 3 mass% or less.

[0029] The organopolysiloxane used as the base polymer (main component) (B) is a linear diorganopolysiloxane whose molecular chain is terminated at both ends with silicon-bonded hydroxyl groups (silanol groups) and / or hydrolyzable silyl groups, where the hydrolyzable silyl groups are preferably alkoxysilyl groups or alkoxy-substituted alkoxysilyl groups.

[0030] When a hydroxyl group (silanol group) bonded to a silicon atom is present, it is preferable that each of the molecular chain terminals has one hydroxyl group (that is, a hydroxysilyl group or a silanol group) bonded to a silicon atom.

[0031] When the hydrolyzable silyl group has an alkoxysilyl group or an alkoxy-substituted alkoxysilyl group at the terminal, it is preferred that both ends of the molecular chain have two or three alkoxy groups bonded to silicon atoms (i.e., alkoxysilyl groups) or alkoxy-substituted alkoxy groups bonded to silicon atoms (i.e., alkoxyalkoxysilyl groups) (i.e., present as dialkoxyorganosilyl groups or bis(alkoxyalkoxy)organosilyl groups, or trialkoxysilyl groups or tris(alkoxyalkoxy)silyl groups).

[0032] The alkoxy group is preferably an alkoxy group having 1 to 10 carbon atoms, particularly 1 to 4 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a tert-butoxy group, a hexyloxy group, and an octyloxy group.

[0033] The alkoxy-substituted alkoxy group is preferably an alkoxy-substituted alkoxy group having 2 to 10 carbon atoms, particularly 2 to 4 carbon atoms, and examples thereof include a methoxyethoxy group, an ethoxyethoxy group, and a methoxypropoxy group.

[0034] As the linear diorganopolysiloxane having both molecular chain terminals blocked with silicon-bonded hydroxyl groups and / or hydrolyzable silyl groups, those having hydroxyl groups (silanol groups), methoxy groups, or ethoxy groups at both terminals, preferably only at both terminals, of the diorganopolysiloxane are particularly preferred.

[0035] Examples of organic groups bonded to silicon atoms other than hydroxyl groups and hydrolyzable groups include unsubstituted or substituted monovalent hydrocarbon groups having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms. Examples of such monovalent hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, hexyl, heptyl, octyl, and 2-ethylhexyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; alkenyl groups such as vinyl and allyl; aryl groups such as phenyl, tolyl, and naphthyl; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl; groups in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups have been substituted with halogen atoms such as fluorine, bromine, or chlorine, or with cyano groups, such as halogenated monovalent hydrocarbon groups such as trifluoropropyl and chloropropyl; and cyanoalkyl groups such as β-cyanoethyl and γ-cyanopropyl. Of these, a methyl group is preferred.

[0036] The viscosity of the organopolysiloxane used as the base polymer (main component) at 23°C is preferably 50 to 1,000,000 mPa·s, and more preferably 100 to 300,000 mPa·s. If the viscosity is below the lower limit, the resulting cured product may not have sufficient mechanical properties, while if it exceeds the upper limit, workability may decrease. In the present invention, the viscosity is the value measured at 23°C using a rotational viscometer (e.g., BL type, BH type, BS type, cone-plate type, rheometer, etc.) (the same applies hereinafter).

[0037] The organopolysiloxane as the base polymer (main component) may be used alone or in combination of two or more.

[0038] The hydrolyzable organosilane compound and / or its partial hydrolysis condensate as the (C) crosslinking agent (curing agent) is a hydrolyzable organosilane compound and / or its partial hydrolysis condensate having three or more silicon-bonded hydrolyzable groups in the molecule (i.e., a siloxane compound such as a siloxane oligomer having three or more residual hydrolyzable groups in the molecule).The (C) component functions as a crosslinking agent (curing agent) in which the three or more hydrolyzable groups present in the molecule undergo a hydrolysis and condensation reaction with the linear diorganopolysiloxane base polymer, both molecular chain terminals of which are blocked with silicon-bonded hydroxyl groups and / or hydrolyzable silyl groups, to form a crosslinked structure.

[0039] Examples of the hydrolyzable group contained in the hydrolyzable organosilane compound include alkoxy groups, alkoxy-substituted alkoxy groups, acyloxy groups, alkenoxy groups, ketoxime groups, aminoxy groups, and amide groups, all of which have 1 to 10 carbon atoms. Examples include alkoxy groups such as methoxy groups, ethoxy groups, and propoxy groups; alkoxy-substituted alkoxy groups such as methoxyethoxy groups, ethoxyethoxy groups, and methoxypropoxy groups; acyloxy groups such as acetoxy groups and octanoyloxy groups; alkenoxy groups such as vinyloxy groups, isopropenoxy groups, and 1-ethyl-2-methylvinyloxy groups; ketoxime groups such as dimethylketoxime groups, methylethylketoxime groups, and methylisobutylketoxime groups; aminoxy groups such as dimethylaminooxy groups and diethylaminooxy groups; and amide groups such as N-methylacetamide groups and N-ethylacetamide groups.

[0040] The hydrolyzable organosilane compound may have an organic group bonded to the silicon atom other than the hydrolyzable group described above. Examples of such organic groups bonded to the silicon atom other than the hydrolyzable group include unsubstituted or substituted monovalent hydrocarbon groups having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms. Examples include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, and octadecyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; alkenyl groups such as vinyl and allyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl, phenethyl, and phenylpropyl; and groups in which some or all of the hydrogen atoms bonded to carbon atoms of these groups have been substituted with halogen atoms such as fluorine, bromine, and chlorine, or with cyano groups, such as halogenated alkyl groups such as 3-chloropropyl and 3,3,3-trifluoropropyl. Of these, preferred unsubstituted or substituted monovalent hydrocarbon groups are methyl, ethyl, propyl, vinyl, and phenyl.

[0041] Examples of hydrolyzable organosilane compounds and their partial hydrolysis condensates include alkoxysilanes such as methyltrimethoxysilane, ethyltrimethoxysilane, decyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, vinyltris(1-cyclopenten-1-yloxy)silane, tetramethoxysilane, and tetraethoxysilane; ketoxime silanes such as methyltris(dimethylketoxime)silane, methyltris(methylethylketoxime)silane, ethyltris(methylethylketoxime)silane, methyltris(methylisobutylketoxime)silane, and vinyltris(methylethylketoxime)silane; methyltri(methoxymethoxy)silane, ethyltri(methoxymethoxy)silane, and vinyltri(methoxymethoxy)silane. alkoxy-substituted alkoxysilanes such as phenyltri(methoxymethoxy)silane, methyltri(ethoxymethoxy)silane, ethyltri(ethoxymethoxy)silane, vinyltri(ethoxymethoxy)silane, phenyltri(ethoxymethoxy)silane, tetra(methoxymethoxy)silane, and tetra(ethoxymethoxy)silane; aminoxysilanes such as methyltris(N,N-diethylaminooxy)silane; amidosilanes such as methyltris(N-methylacetamido)silane, methyltris(N-butylacetamido)silane, and methyltris(N-cyclohexylacetamido)silane; alkenoxysilanes such as methyltriisopropenoxysilane, vinyltriisopropenoxysilane, and phenyltriisopropenoxysilane; acyloxysilanes such as methyltriacetoxysilane and vinyltriacetoxysilane, and partial hydrolysis condensates of these hydrolyzable organosilane compounds.

[0042] The hydrolyzable organosilane compound as a crosslinking agent (curing agent) is clearly distinguishable from the silane coupling agent (E) as an adhesion promoter, which will be described later, in that the hydrolyzable organosilane compound does not contain in the molecule a monovalent hydrocarbon group substituted with a functional group having a heteroatom such as a nitrogen atom, an oxygen atom, or a sulfur atom.

[0043] The hydrolyzable organosilane compounds and / or their partial hydrolyzed condensates may be used singly or in combination of two or more.

[0044] The amount of hydrolyzable organosilane compound and / or its partial hydrolysis condensate as a crosslinking agent (curing agent) is 0.1 to 40 parts by mass, preferably 1 to 20 parts by mass, per 100 parts by mass of a linear diorganopolysiloxane having both molecular chain terminals capped with silicon-bonded hydroxyl groups and / or hydrolyzable silyl groups. If the amount of hydrolyzable organosilane compound and / or its partial hydrolysis condensate is less than the above-mentioned lower limit (0.1 part by mass), curability and storage stability may be reduced. On the other hand, if the amount exceeds the above-mentioned upper limit (40 parts by mass), not only will it be uneconomical, but the resulting cured product may have reduced elongation and durability.

[0045] The (D) curing catalyst can be a condensation catalyst that has traditionally been commonly used as a curing accelerator for condensation-curable liquid silicone adhesives (room-temperature-curable organopolysiloxane compositions). Examples of such catalysts include organotin compounds such as dibutyltin methoxide, dibutyltin diacetate, dibutyltin dioctate, dibutyltin dilaurate, dioctyltin dilaurate, dioctyltin dioctate, dioctyltin dineodecanoate, dimethyltin dimethoxide, and dimethyltin diacetate; organotitanium compounds such as tetrapropyl titanate, tetrabutyl titanate, tetra-2-ethylhexyl titanate, diisopropoxytitanium bis(ethylacetoacetate), and dimethoxytitanium diacetylacetonate; and amine compounds such as hexylamine and tetramethylguanidylpropyltrimethoxysilane, as well as salts thereof. These may be used alone or in combination of two or more.

[0046] The amount of curing catalyst blended is 0.001 to 20 parts by mass, preferably 0.005 to 5 parts by mass, and more preferably 0.01 to 2 parts by mass, per 100 parts by mass of the linear diorganopolysiloxane terminally capped with silicon-bonded hydroxyl groups and / or hydrolyzable silyl groups. If the blended amount of curing catalyst is less than the lower limit (0.001 part by mass), the catalytic effect may not be obtained. On the other hand, if the blended amount of curing catalyst exceeds the upper limit (20 parts by mass), not only is it uneconomical, but the durability or adhesiveness of the composition may also decrease.

[0047] The condensation-curing liquid silicone adhesive further contains, as component (E), a silane coupling agent (a hydrolyzable silane compound having in its molecule a monovalent hydrocarbon group substituted with a functional group (excluding guanidyl groups) having a heteroatom such as a nitrogen atom, oxygen atom or sulfur atom, a so-called carbon functional silane compound) that improves adhesive strength and also acts as an adhesion-imparting component.

[0048] The silane coupling agent used as the adhesion-imparting component is preferably a silane coupling agent known in the art. In particular, those having an alkoxy group or an alkenoxy group as the hydrolyzable group are preferred, and specific examples include alkoxy groups such as methoxy, ethoxy, and propoxy, and alkenoxy groups such as vinyloxy, isopropenoxy, and 1-ethyl-2-methylvinyloxy.

[0049] Furthermore, the monovalent hydrocarbon group substituted with a functional group (excluding guanidyl groups) having a hetero atom such as a nitrogen atom, oxygen atom, or sulfur atom is preferably a monovalent hydrocarbon group having 1 to 20 carbon atoms and at least one unsubstituted or substituted amino group, unsubstituted or substituted imino group, mercapto group, epoxy group, or (meth)acryloxy group, and specifically, a γ-acryloxypropyl group, a γ-methacryloxypropyl group, a β-(3,4-epoxycyclohexyl)ethyl group, a γ-glycidoxypropyl group, an N-β(aminoethyl)γ-aminopropyl group, a γ-aminopropyl group, or a group represented by the following formula: and a γ-mercaptopropyl group.

[0050] The silane coupling agent may have an organic group bonded to the silicon atom other than the monovalent hydrocarbon group substituted with the hydrolyzable group or functional group. The organic group bonded to the silicon atom other than the monovalent hydrocarbon group substituted with the hydrolyzable group or functional group is preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms, such as alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, hexyl, heptyl, and octyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; alkenyl groups such as vinyl and allyl; aryl groups such as phenyl, tolyl, and xylyl; and aralkyl groups such as benzyl and phenethyl. Of these, methyl and ethyl groups are preferred.

[0051] Specific examples of the silane coupling agent include γ-acryloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and compounds of the following formula: Examples include silane compounds represented by the formula (I), γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltriisopropenoxysilane, γ-glycidoxypropylmethyldiisopropenoxysilane, etc. In particular, the use of an amino group-containing silane coupling agent is preferred.

[0052] The silane coupling agents may be used alone or in combination of two or more.

[0053] The amount of silane coupling agent (component (E)) blended is 0.05 to 20 parts by mass, preferably 0.1 to 15 parts by mass, and particularly preferably 0.5 to 10 parts by mass, per 100 parts by mass of linear diorganopolysiloxane having both molecular chain terminals capped with silicon-bonded hydroxyl groups and / or hydrolyzable silyl groups. If the amount is less than 0.05 parts by mass, sufficient adhesion cannot be obtained, and if it exceeds 20 parts by mass, the resulting cured product will have poor weather resistance and mechanical properties.

[0054] In addition to the components described above, the condensation-curable liquid silicone adhesive can contain optional components within the scope of the present invention. These optional components include inorganic fillers other than component (A), colorants such as pigments, dyes, and fluorescent brighteners, antibacterial agents, antifungal agents, and plasticizers such as silicone oil (non-functional organopolysiloxane).

[0055] Specific examples of this optional inorganic filler other than component (A) include carbon such as acetylene black, dry-process silica (fumed silica, etc.), wet-process silica (precipitated silica, etc.), fine quartz powder, diatomaceous earth powder, fine particle alumina, magnesia powder, calcium carbonate such as colloidal calcium carbonate and heavy calcium carbonate, and fine powder inorganic fillers (excluding component (A)) obtained by surface-treating these with silanes, silazanes, low-polymerization polysiloxanes, etc. When an inorganic filler other than component (A) is blended, the blending amount thereof is preferably 0.1 to 800 parts by mass, more preferably 0.5 to 600 parts by mass, per 100 parts by mass of the linear diorganopolysiloxane the molecular chain of which is terminally blocked with silicon-bonded hydroxyl groups and / or hydrolyzable silyl groups.

[0056] The condensation-curing liquid silicone adhesive can be prepared by uniformly mixing the above-mentioned components in a known mixer in a moisture-blocking state (in a dry atmosphere or under reduced pressure) in accordance with a conventional method.

[0057] The resulting condensation-curable liquid silicone adhesive will cure, for example, by leaving it at room temperature (23°C ± 15°C). The molding method, curing conditions, etc. can be any known method and condition suited to the type of condensation-curable liquid silicone adhesive. For example, the adhesive can be cured by leaving it to stand in the atmosphere under conditions of 23°C / 50% RH for several hours to several days (e.g., 6 hours to 7 days).

[0058] [Addition Reaction Curable Liquid Silicone Adhesive] The addition reaction curable liquid silicone adhesive is a liquid silicone adhesive that contains, in addition to the above-mentioned (A) hydroxide compound having a decomposition temperature of 180 to 600°C, (F) an alkenyl group-containing organopolysiloxane (base polymer) having alkenyl groups such as vinyl groups bonded to silicon atoms at the molecular chain terminals, (G) an organohydrogenpolysiloxane (crosslinking agent) having at least two silicon-bonded hydrogen atoms (SiH groups) per molecule, (H) a platinum group metal catalyst (hydrosilylation addition reaction catalyst), and (I) an adhesion promoter, and crosslinks via an addition reaction of SiH groups to vinyl groups (hydrosilylation reaction) to yield a cured product. The addition reaction curing liquid silicone adhesive is preferably an easily dismantlable addition reaction curing liquid silicone adhesive containing: (A) a hydroxide compound having a decomposition temperature of 180 to 600°C: in an amount that accounts for 25 to 80 mass% of the total adhesive; (F) 100 parts by mass of an alkenyl-containing organopolysiloxane having silicon-bonded alkenyl groups at molecular chain terminals; (G) an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in the molecule: in an amount that provides 0.01 to 3 moles of silicon-bonded hydrogen atoms per mole of silicon-bonded alkenyl groups in component (F); (H) a platinum group metal catalyst: in an amount calculated as 0.01 to 1,000 ppm by mass of platinum group metal atoms relative to the total amount of components (F) and (G); and (I) an adhesion promoter: 0.05 to 20 parts by mass, and wherein the content of the electromagnetically-induced heat-generating material is 3 mass% or less.

[0059] The alkenyl-containing organopolysiloxane (F) serving as the base polymer (main component) is a linear diorganopolysiloxane whose molecular chain ends (one or both ends) are blocked with silyl groups containing an alkenyl group, such as a vinyl group, bonded to a silicon atom, and which has an average of at least one, preferably two or more (usually 2 to 20, particularly 2 to 10, and even more preferably 2 to 5) silicon-bonded alkenyl groups per molecule. Examples of the alkenyl group include lower alkenyl groups typically having 2 to 6 carbon atoms, preferably about 2 to 4 carbon atoms, such as vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, and cyclohexenyl. The alkenyl group-containing organopolysiloxane used as the base polymer (main component) may have alkenyl groups in side chains on the molecular chain, as long as it has alkenyl groups bonded to silicon atoms at one or both ends of the molecular chain.

[0060] Furthermore, the silicon-bonded organic group other than the silicon-bonded alkenyl group is not particularly limited as long as it does not have an aliphatic unsaturated bond, and examples thereof include unsubstituted or substituted monovalent hydrocarbon groups excluding aliphatic unsaturated bonds, which typically have 1 to 12 carbon atoms, preferably 1 to 10. Examples of such unsubstituted or substituted monovalent hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl and phenethyl; and halogenated alkyl groups in which some or all of the hydrogen atoms in these groups have been substituted with halogen atoms such as chlorine, fluorine, and bromine, such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl. Preferred are alkyl groups and aryl groups, and more preferably methyl and phenyl groups.

[0061] Specific examples of the alkenyl group-containing organopolysiloxane include dimethylpolysiloxanes both ends blocked with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymers both ends blocked with dimethylvinylsiloxy groups, dimethylsiloxane-diphenylsiloxane copolymers both ends blocked with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane-diphenylsiloxane copolymers both ends blocked with dimethylvinylsiloxy groups, methyltrifluoropropylpolysiloxanes both ends blocked with dimethylvinylsiloxy groups, and dimethylvinylsiloxanes both ends blocked with dimethylvinylsiloxy groups. Siloxy-blocked dimethylsiloxane / methyltrifluoropropylsiloxane copolymer, dimethylvinylsiloxy-blocked dimethylsiloxane / methyltrifluoropropylsiloxane / methylvinylsiloxane copolymer at both ends, methyldivinylsiloxy-blocked dimethylpolysiloxane, methyldivinylsiloxy-blocked dimethylsiloxane / methylvinylsiloxane copolymer at both ends, methyldivinylsiloxy-blocked dimethylsiloxane / diphenylsiloxane copolymer at both ends, methyldivinylsiloxy-blocked dimethylsiloxane copolymer of vinyl siloxane and diphenyl siloxane, methyl trifluoropropyl polysiloxane end-blocked with methyl divinyl siloxy groups, copolymer of dimethyl siloxane and methyl trifluoropropyl siloxane end-blocked with methyl divinyl siloxy groups, copolymer of dimethyl siloxane, methyl trifluoropropyl siloxane and methyl vinyl siloxane end-blocked with methyl divinyl siloxy groups, dimethyl polysiloxane end-blocked with trivinyl siloxy groups, dimethyl siloxane and methyl vinyl siloxane end-blocked with trivinyl siloxy groups copolymer, dimethylsiloxane-diphenylsiloxane copolymer both ends blocked with trivinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane-diphenylsiloxane copolymer both ends blocked with trivinylsiloxy groups, methyltrifluoropropylpolysiloxane both ends blocked with trivinylsiloxy groups, dimethylsiloxane-methyltrifluoropropylsiloxane copolymer both ends blocked with trivinylsiloxy groups, dimethylsiloxane-methyltrifluoropropylsiloxane-methylvinylsiloxane copolymer both ends blocked with trivinylsiloxy groups,Dimethylpolysiloxane with one end capped with trimethylsiloxy groups and the other end capped with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymer with one end capped with trimethylsiloxy groups and the other end capped with dimethylvinylsiloxy groups, dimethylsiloxane-diphenylsiloxane copolymer with one end capped with trimethylsiloxy groups and the other end capped with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymer with one end capped with trimethylsiloxy groups and the other end capped with dimethylvinylsiloxy groups, Examples of such copolymers include diphenylsiloxane copolymers, methyltrifluoropropylpolysiloxanes having one end blocked with a trimethylsiloxy group and the other end blocked with a dimethylvinylsiloxy group, dimethylsiloxane-methyltrifluoropropylsiloxane copolymers having one end blocked with a trimethylsiloxy group and the other end blocked with a dimethylvinylsiloxy group, and dimethylsiloxane-methyltrifluoropropylsiloxane-methylvinylsiloxane copolymers having one end blocked with a trimethylsiloxy group and the other end blocked with a dimethylvinylsiloxy group.

[0062] The viscosity at 23° C. of the alkenyl group-containing organopolysiloxane used as the base polymer (main component) is preferably 100 to 500,000 mPa·s, and more preferably 700 to 100,000 mPa·s.

[0063] The alkenyl group-containing organopolysiloxane as the base polymer (main component) may be used either alone or in combination of two or more.

[0064] The organohydrogenpolysiloxane (G) used as the crosslinking agent (curing agent) has, on average, at least two, preferably at least three, more preferably up to 500, even more preferably up to 200, and particularly preferably up to 100 silicon-bonded hydrogen atoms (SiH groups) per molecule, and preferably has no aliphatic unsaturated bonds per molecule.

[0065] In this organohydrogenpolysiloxane, the silicon-bonded organic group other than silicon-bonded hydrogen atoms is not particularly limited, and examples include unsubstituted or substituted monovalent hydrocarbon groups having a carbon atom number of typically 1 to 10, preferably 1 to 6. Specific examples include the same groups as those exemplified as silicon-bonded organic groups other than silicon-bonded alkenyl groups in the description of the alkenyl-group-containing organopolysiloxane, as well as alkenyl groups such as vinyl groups and allyl groups. Preferred are unsubstituted monovalent hydrocarbon groups that do not contain aliphatic unsaturated bonds, such as alkyl groups and aryl groups, and more preferred are methyl groups, phenyl groups, etc.

[0066] Preferably, the number of silicon atoms in the molecule is 2 to 300, preferably 3 to 150, and particularly about 4 to 100, and the organohydrogenpolysiloxane is liquid at room temperature. The hydrogen atoms bonded to the silicon atoms may be located at either the terminals of the molecular chain, the middle (non-terminal) of the molecular chain, or both. The molecular structure of the organohydrogenpolysiloxane may be linear, cyclic, branched, or three-dimensional network. In the present invention, the degree of polymerization (or the number of repeating diorganosiloxane units constituting the main chain, which is a measure of the number of silicon atoms in the molecule) can be determined as the polystyrene-equivalent number-average degree of polymerization (or number-average molecular weight) by gel permeation chromatography (GPC) analysis using, for example, toluene as a developing solvent.

[0067] Examples of organohydrogenpolysiloxanes include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, tris(hydrogendimethylsiloxy)methylsilane, tris(hydrogendimethylsiloxy)phenylsilane, methylhydrogencyclopolysiloxane, methylhydrogensiloxane-dimethylsiloxane cyclic copolymer, methylhydrogenpolysiloxane capped at both ends with trimethylsiloxy groups, dimethylsiloxane-methylhydrogensiloxane copolymer capped at both ends with trimethylsiloxy groups, dimethylpolysiloxane capped at both ends with dimethylhydrogensiloxy groups, dimethylsiloxane capped at both ends with dimethylhydrogensiloxy groups, copolymer of methylhydrogensiloxane and methylhydrogensiloxane, copolymer of methylhydrogensiloxane and diphenylsiloxane both ends blocked with trimethylsiloxy groups, copolymer of methylhydrogensiloxane, diphenylsiloxane and dimethylsiloxane both ends blocked with trimethylsiloxy groups, copolymer of methylhydrogensiloxane, methylphenylsiloxane and dimethylsiloxane both ends blocked with trimethylsiloxy groups, copolymer of methylhydrogensiloxane, dimethylsiloxane and diphenylsiloxane both ends blocked with dimethylhydrogensiloxy groups, copolymer of methylhydrogensiloxane, dimethylsiloxane and methylphenylsiloxane both ends blocked with dimethylhydrogensiloxy groups, (CH3)2HSiO 1 / 2 Units and (CH3)3SiO 1 / 2 Units and SiO 4 / 2 a copolymer consisting of (CH3)2HSiO units, 1 / 2 Units and SiO 4 / 2 a copolymer consisting of (CH3)2HSiO units, 1 / 2 Units and SiO 4 / 2 Units and (C6H5)SiO 3 / 2and copolymers consisting of these exemplified compounds in which some or all of the methyl groups have been substituted with other alkyl groups, phenyl groups, etc. Component (G) organohydrogenpolysiloxanes having at least two silicon-bonded hydrogen atoms per molecule are clearly distinguished from the adhesion promoters of component (I), which will be described later, in that they do not have functional groups such as epoxy groups or alkoxysilyl groups as silicon-bonded organic groups other than silicon-bonded hydrogen atoms per molecule.

[0068] The organohydrogenpolysiloxanes may be used alone or in combination of two or more.

[0069] The amount of organohydrogenpolysiloxane added is an amount such that the amount of silicon-bonded hydrogen atoms (SiH groups) is 0.01 to 3 moles, preferably 0.05 to 2.5 moles, and more preferably 0.2 to 2 moles per mole of silicon-bonded alkenyl groups in the alkenyl group-containing organopolysiloxane.

[0070] (H) Platinum group metal catalyst (hydrosilylation addition catalyst) is used as a catalyst to promote the addition reaction between silicon-bonded alkenyl groups in an alkenyl-group-containing organopolysiloxane and silicon-bonded hydrogen atoms in an organohydrogenpolysiloxane. Known platinum group metal catalysts can be used. Specific examples include platinum-based catalysts such as platinum black, chloroplatinic acid, alcohol-modified chloroplatinic acid, and complexes of chloroplatinic acid with olefins, aldehydes, vinylsiloxanes, or acetylene alcohols.

[0071] The amount of platinum group metal catalyst used may be an effective amount, which can be increased or decreased as appropriate depending on the desired curing rate, but is typically in the range of 0.01 to 1,000 ppm, preferably 0.1 to 500 ppm, and more preferably 1 to 300 ppm, calculated as platinum group metal atoms by mass relative to the total amount of alkenyl group-containing organopolysiloxane and organohydrogenpolysiloxane. If this amount is too high, the heat resistance of the resulting cured product may decrease.

[0072] Component (I) is an adhesion promoter that imparts self-adhesion to the composition of the present invention. It is preferable that the self-adhesion is particularly good with respect to metals and organic resins. Examples of component (I) include organosilanes having at least one, and preferably two or more, functional groups selected from the group consisting of alkenyl groups such as vinyl groups, (meth)acryloxy groups, hydrosilyl groups (SiH groups), epoxy groups, alkoxysilyl groups, carbonyl groups, and phenyl groups; functional group-containing organosilicon compounds such as cyclic or linear organopolysiloxanes having 2 to 30, and preferably about 4 to 20, silicon atoms (excluding components (F) and (G)); and non-silicon (i.e., silicon-free) hydrocarbon compounds having 1 to 4, and preferably 1 to 2, aromatic rings such as mono- to tetravalent, and preferably di- or tetravalent phenylene structures per molecule, and at least 1, and preferably 2 to 4, functional groups capable of participating in a hydrosilylation addition reaction (e.g., alkenyl groups, (meth)acryloxy groups) per molecule, which may contain oxygen atoms in the molecule.

[0073] Specific examples of such component (I) include the functional group-containing organoalkoxysilanes and functional group-containing organohydrogenpolysiloxanes exemplified below, and functional group-containing organosilicon compounds in which the total number of repeating bifunctional siloxane units in the functional group-containing linear organohydrogenpolysiloxanes in the exemplary compounds below is any positive integer in the range of 3 to 28, as well as bisphenol compounds (bisphenol F, bisphenol A, bisphenol AF, etc.) or derivatives of oligomers thereof in which the hydroxyl groups at both ends of the molecular chain are blocked with alkenyloxy groups or (meth)acryloxy-substituted alkyloxy groups.

[0074]

[0075] Component (I) can be used either alone or in combination of two or more different compounds. However, from the standpoint of adhesion to substrates, it is preferred to use an organosilicon compound in combination with a non-silicon organic compound.

[0076] The amount of component (I) to be blended is an amount that enables the composition of the present invention to obtain good self-adhesion to adherends, particularly metals and organic resins, and is, for example, 0.05 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, and particularly preferably 0.5 to 10 parts by mass, per 100 parts by mass of component (F). If it is less than 0.05 part by mass, sufficient adhesion may not be obtained, and if it exceeds 20 parts by mass, the resulting cured product may have poor weather resistance and mechanical properties.

[0077] In addition to the above components, the addition reaction curable liquid silicone adhesive can contain optional components within a range that does not impair the object of the present invention. These optional components include, for example, a reaction inhibitor, the same inorganic fillers as those exemplified in the condensation curable liquid silicone adhesive described above (excluding hydroxide compounds whose decomposition temperature of component (A) is 180 to 600°C), organopolysiloxanes that do not contain silicon-bonded hydrogen atoms (SiH groups) or silicon-bonded alkenyl groups (so-called non-functional silicone oils), heat resistance additives, flame retardants, thixotropy-imparting agents, pigments, dyes, etc.

[0078] The addition reaction curing liquid silicone adhesive can be prepared by uniformly mixing the above-mentioned components using a known mixer in accordance with a conventional method.

[0079] The curing conditions for the addition reaction curing liquid silicone adhesive may be 23 to 150°C, especially 23 to 100°C, for 10 minutes to 8 hours, especially 30 minutes to 5 hours.

[0080] [UV-Curable Liquid Silicone Adhesive] The UV-curable liquid silicone adhesive contains, in addition to the above-mentioned (A) hydroxide compound having a decomposition temperature of 180 to 600°C, (J) UV-reactive organopolysiloxane (base polymer), and (K) photopolymerization initiator, and is a liquid silicone adhesive that crosslinks upon irradiation with UV light to produce a cured product. The UV-curable liquid silicone adhesive is preferably an easily dismantled UV-curable liquid silicone adhesive that contains: (A) hydroxide compound having a decomposition temperature of 180 to 600°C: in an amount that accounts for 25 to 80 mass% of the total adhesive; (J) UV-reactive organopolysiloxane: 100 parts by mass; and (K) photopolymerization initiator: 0.01 to 10 parts by mass, and the content of the material that generates heat upon electromagnetic induction is 3 mass% or less.

[0081] The UV-reactive organopolysiloxane of component (J) is not particularly limited as long as it functions as a base polymer in the UV-curable silicone composition, and is preferably an organopolysiloxane having at least two UV-reactive groups per molecule, more preferably 2 to 20, and particularly preferably 2 to 10. The multiple UV-reactive groups present in this organopolysiloxane may all be the same or different.

[0082] Examples of the ultraviolet-reactive group include alkenyl groups such as vinyl, allyl, and propenyl groups; alkenyloxy groups such as vinyloxy, allyloxy, propenyloxy, and isopropenyloxy groups; aliphatic unsaturated groups other than alkenyl groups such as acryloyl and methacryloyl groups; epoxy groups; and hydrosilyl groups. Preferred are acryloyl, methacryloyl, mercapto, epoxy, and hydrosilyl groups, and more preferred are acryloyl and methacryloyl groups.

[0083] Furthermore, the silicon-bonded organic group other than the silicon-bonded alkenyl group is not particularly limited as long as it does not have an aliphatic unsaturated bond, and examples thereof include unsubstituted or substituted monovalent hydrocarbon groups excluding aliphatic unsaturated bonds, which typically have 1 to 12 carbon atoms, preferably 1 to 10. Examples of such unsubstituted or substituted monovalent hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl and phenethyl; and halogenated alkyl groups in which some or all of the hydrogen atoms in these groups have been substituted with halogen atoms such as chlorine, fluorine, and bromine, such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl. Preferred are alkyl groups and aryl groups, and more preferably methyl and phenyl groups.

[0084] Specific examples of organopolysiloxanes containing ultraviolet reactive groups include dimethylpolysiloxanes blocked at both ends with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymers blocked at both ends with dimethylvinylsiloxy groups, dimethylsiloxane-diphenylsiloxane copolymers blocked at both ends with dimethylvinylsiloxy groups, dimethylpolysiloxanes blocked at both ends with dimethylacryloylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymers blocked at both ends with dimethylacryloylsiloxy groups, and dimethyl Siloxane-diphenylsiloxane copolymer, dimethylpolysiloxane capped at both ends with dimethylmethacryloylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymer capped at both ends with dimethylmethacryloylsiloxy groups, dimethylsiloxane-diphenylsiloxane copolymer capped at both ends with dimethylmercaptosiloxy groups, dimethylpolysiloxane capped at both ends with dimethylmercaptosiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymer capped at both ends with dimethylmercaptosiloxy groups, Methylsiloxane-diphenylsiloxane copolymer, dimethylpolysiloxane capped at both ends with dimethylepoxysiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymer capped at both ends with dimethylepoxysiloxy groups, dimethylsiloxane-diphenylsiloxane copolymer capped at both ends with dimethylepoxysiloxy groups, dimethylpolysiloxane capped at both ends with methyldivinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymer capped at both ends with methyldivinylsiloxy groups, dimethylsiloxane-diphenylsiloxane copolymer capped at both ends with methyldivinylsiloxy groups methylvinylsiloxane copolymer, dimethylpolysiloxane capped at both ends with methyldiacryloylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymer capped at both ends with methyldiacryloylsiloxy groups, dimethylsiloxane-diphenylsiloxane copolymer capped at both ends with methyldiacryloylsiloxy groups, dimethylpolysiloxane capped at both ends with trivinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymer capped at both ends with trivinylsiloxy groups, dimethylsiloxane-diphenylsiloxane copolymer capped at both ends with trivinylsiloxy groups,Examples include dimethylpolysiloxanes in which one end is capped with a trimethylsiloxy group and the other end with a dimethylvinylsiloxy group, dimethylsiloxane-methylvinylsiloxane copolymers in which one end is capped with a trimethylsiloxy group and the other end with a dimethylvinylsiloxy group, and dimethylsiloxane-diphenylsiloxane copolymers in which one end is capped with a trimethylsiloxy group and the other end with a dimethylvinylsiloxy group.

[0085] The viscosity of the ultraviolet-reactive organopolysiloxane at 23° C. is preferably 100 to 500,000 mPa·s, and more preferably 700 to 100,000 mPa·s.

[0086] The ultraviolet-reactive organopolysiloxane may be used alone or in combination of two or more.

[0087] The photopolymerization initiator of component (K) has the effect of promoting the photopolymerization of the ultraviolet-reactive groups in component (J). Component (K) is not particularly limited, and specific examples include acetophenone, propiophenone, benzophenone, xanthol, fluorene, benzaldehyde, anthraquinone, triphenylamine, 4-methylacetophenone, 3-pentylacetophenone, 4-methoxyacetophenone, 3-bromoacetophenone, 4-allylacetophenone, p-diacetylbenzene, 3-methoxybenzophenone, 4-methylbenzophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4-chloro-4'-benzylbenzophenone, 3-chloroxanthone, 3,9-dichloroxanthone, 3-chloro-8-nonylxanthone, benzoin, benzoin methyl ether, benzoin butyl ether, bis(4-dimethylaminophenyl)ketone, benzyl methoxyacetal, 2-chlorothioxanthone, and the like. Examples of the photopolymerization initiator include santone, diethylacetophenone, 1-hydroxychlorophenyl ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-(4-(methylthio)phenyl)-2-morpholino-1-propane, 2,2-dimethoxy-2-phenylacetophenone, diethoxyacetophenone, and 2-hydroxy-2-methyl-1-phenylpropan-1-one. From the viewpoint of high purity, preferred are benzophenone, 4-methoxyacetophenone, 4-methylbenzophenone, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, and 2-hydroxy-2-methyl-1-phenylpropan-1-one, and more preferred are diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, and 2-hydroxy-2-methyl-1-phenylpropan-1-one. These photopolymerization initiators may be used alone or in combination of two or more.

[0088] The amount of component (K) added is not particularly limited, but is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 3 parts by mass, and even more preferably 0.5 to 3 parts by mass, per 100 parts by mass of component (J). When the amount of component (K) added is within this range, it is easy to control the curing of the ultraviolet-curable liquid silicone adhesive.

[0089] The ultraviolet-curable liquid silicone adhesive may be a liquid silicone adhesive that is both ultraviolet-curable and condensation-curable, or a liquid silicone adhesive that is both ultraviolet-curable and addition-curable.

[0090] A liquid silicone adhesive that is both UV-curable and condensation-curable uses the above-mentioned (A) hydroxide compound having a decomposition temperature of 180 to 600°C, as well as the above-mentioned components (B) and (J) as base polymers, the above-mentioned component (C) as a curing agent or a component having both a substituent that reacts with UV light and a substituent that condenses, the above-mentioned component (D) as a condensation-curing catalyst, the above-mentioned component (K) as a UV-curing catalyst, and the above-mentioned component (E) as an adhesion-imparting component.

[0091] The liquid silicone adhesive that is both UV-curable and addition-curable uses the above-mentioned hydroxylated compound (A) having a decomposition temperature of 180 to 600°C, as well as the above-mentioned components (F) and (J) as base polymers, the above-mentioned component (G) as a curing agent, the above-mentioned component (H) as an addition-curing catalyst, the above-mentioned component (K) as a UV-curing catalyst, and the above-mentioned component (I) as an adhesion-imparting component.

[0092] The ultraviolet-curable liquid silicone adhesive can be prepared by uniformly mixing the above-mentioned components using a known mixer in accordance with a conventional method.

[0093] The ultraviolet-curable liquid silicone adhesive is cured by irradiating it with ultraviolet light. The ultraviolet irradiation conditions are not particularly limited, but an ultraviolet light emitting diode with an emission wavelength of 365 nm is used, and the illuminance is 5 to 500 mW / cm. 2 , preferably 10 to 200 mW / cm 2 , light intensity 0.5-100J / cm 2 , preferably 10 to 50 J / cm 2 It is preferable to set the following.

[0094] [Bonded Members] In the method for dismantling bonded members of the present invention, the bonded members are formed by bonding multiple (particularly two) members, including members in which at least a portion of the bonding interface is metal, with a cured product (an adhesive member made of an adhesive silicone rubber cured product) obtained by curing a curable liquid silicone adhesive containing a specific amount of a hydroxide compound having a decomposition temperature of 180 to 600°C and containing 3% by mass or less of a material that generates heat through electromagnetic induction. The members may be the same or different members. In the bonded member, one of the bonded members is a member in which at least a portion of the bonding interface is metal, and the other member may be selected from the group consisting of the same member (a member in which at least a portion of the bonding interface is metal), an organic resin member, and a metal member.

[0095] The members having at least a part of the bonding interface made of metal may be made entirely of metal, provided that the bonding interface is at least made of metal. Note that the metal at the bonding interface of the members may have an area that is sufficiently heated by electromagnetic induction.

[0096] Specific examples of members in which at least a portion of the joining interface is made of metal include automotive parts and electric / electronic parts made of aluminum alloys such as A1050, A2017, A5052, A5083, A6061, and A1N30; aluminum alloy die-casts such as ADC1, ADC3, ADC10, ADC12, and ADC14; carbon steels such as SPCC, SS400, and SAPH; stainless steels such as SUS304 and SUS430; and magnesium alloys such as AZ-91D and AM50A.

[0097] The metals constituting the metal member and the member in which at least a portion of the joining interface is metal may be magnetic or non-magnetic as long as they are capable of generating heat through electromagnetic induction. Examples include pure metals such as aluminum, iron, and copper, and alloys containing these (aluminum alloys (aluminum alloy die-casts such as Al-Cu-Si alloys (ADC12)), carbon steel (SPCC, SS400, SAPH, etc.), cast iron (Fe-Si-C ternary alloys), stainless steel (particularly ferritic), copper alloys (brass, bronze, cupronickel), nichrome, magnesium alloys (AZ-91D, AM50A, etc.), titanium alloys, etc.). Note that a magnetic material refers to a metal material whose relative permeability (μ / μ), which is the ratio of the vacuum permeability (μ) to the initial permeability (μ), is 5 or more, and even 50 or more.

[0098] Examples of organic resins that make up organic resin components include polyamide resins such as PBT (polybutylene terephthalate resin), PPS (polyphenylene sulfide resin), PA66 (nylon 66), PA6 (nylon 6), and PC (polycarbonate resin).

[0099] The organic resin or metal constituting the member having at least a part of the bonding interface made of metal, the organic resin member or the metal member preferably has a heat resistance temperature of 160° C. or higher.

[0100] [Method for Producing Bonded Members] A curable liquid silicone adhesive containing a hydroxide compound with a decomposition temperature of 180 to 600°C and containing 3% by mass or less of a material that generates heat upon electromagnetic induction is applied to the surface of one of the members by hand or machine dispensing in the shape of the joining location (e.g., a gasket, etc.), and the other member is then bonded and cured. The adhesive is then secured with bolts or the like as needed. When the curable liquid silicone adhesive of the present invention is a condensation-curing liquid silicone adhesive, it cures due to moisture in the air at room temperature, so curing progresses simply by leaving the multiple members after joining. Humidification is effective when increasing the curing rate. When the curable liquid silicone adhesive of the present invention is an addition-reaction-curing liquid silicone adhesive, it cures via an addition reaction at temperatures of 23 to 150°C, so curing progresses simply by leaving the multiple members after joining or heating. When the curable liquid silicone adhesive of the present invention is an ultraviolet-curing liquid silicone adhesive, the photopolymerization initiator reacts upon irradiation with ultraviolet light, causing the curing reaction to progress and harden. If necessary, a secondary cure may be carried out, and the temperature conditions for this are preferably 120° C. or higher, more preferably 150° C. or higher, but lower than the decomposition temperature of the hydroxide compound and 250° C. or lower. The curing time is preferably 10 minutes to 48 hours, more preferably 30 minutes to 24 hours.

[0101] Examples of the joining member include automobile parts such as engines, transmissions, and automobile electrical components (ECUs (Electronic Control Units) and PCUs (Power Control Units)), as well as electric and electronic parts such as smartphones, tablets, liquid crystal displays, and batteries. Of these, automobile parts and electric and electronic parts are preferred.

[0102] The above-mentioned joining member is one that maintains the joined state of the members at an ambient temperature of 150°C or less, preferably at room temperature to 120°C.

[0103] The above-mentioned joining members are preferably easily dismantled, being joined with a certain degree of adhesive strength during normal use, but whose adhesive strength decreases to such an extent that the members can be separated after electromagnetic induction heating. Specifically, the initial shear adhesive strength of the joining members is preferably 1.2 MPa or more, particularly 1.5 MPa or more, and the shear adhesive strength of the joining members after electromagnetic induction heating is preferably 1 MPa or less. This shear adhesive strength is a value measured in accordance with the method specified in JIS K6850. Note that the initial and post-electromagnetic induction heating shear adhesive strengths within the above-mentioned ranges can be achieved by using a curable liquid silicone adhesive with a composition within the above-mentioned specific range.

[0104] [Dismantling Method] The method for dismantling bonded members of the present invention involves heating the metal portions of the bonded interface of the bonded members by electromagnetic induction, indirectly heating the portion or all of the cured product (cured adhesive silicone rubber product) formed by curing the curable liquid silicone adhesive that serves as the adhesive member that is in contact with the metal to 160°C to 800°C, causing the metal members to peel off naturally, or by manually applying force to the metal members or by using a tool such as a scraper to peel them off from the metal members, thereby dismantling the bonded members. The dismantled members can also be recycled.

[0105] The disassembly of components according to the present invention is presumably possible for the following reasons: The metal and adhesive forming the bonding interface have a large difference in linear expansion coefficient. Therefore, when heated, the difference in thermal expansion exerts a large thermal stress on the bonding interface. Furthermore, in the case of bonding components made of dissimilar materials, the difference in thermal expansion also exerts thermal stress between the bonding components. Furthermore, when the metal at the bonding interface is heated by electromagnetic induction, the hydroxide compound (A) in the cured product (cured adhesive silicone rubber product) obtained by curing the curable liquid silicone adhesive, which is the bonding component, is heated and decomposes to generate water. The generated water then vaporizes, causing foaming and a decrease in adhesive strength. As a result, the bonded components can be disassembled more quickly.

[0106] The frequency, power, and time for electromagnetic induction heating are preferably such that the members can be separated. The frequency can be selected from the range of 100 kHz to 500 kHz, and the power can be selected from the range of 500 W to 5 kW. The heating time by electromagnetic induction is not particularly limited, but is 2 minutes or less, preferably 1 minute or less, and more preferably 20 seconds or less.

[0107] Next, the present invention will be specifically explained using composition examples, composition comparison examples, and examples and comparative examples, but the present invention is not limited to the following examples. In the following examples, the room temperature is 23°C, the viscosity is the value measured at 23°C using a rotational viscometer, and the average particle size is the value determined as the cumulative weight average value D50 (or median size) using a particle size distribution measuring device using a laser light diffraction method. The BET specific surface area is a value calculated using the BET equation from an isothermal adsorption curve measured by a nitrogen gas adsorption method.

[0108] Preparation of Curable Liquid Silicone Adhesive (Composition) [Composition Example 1] A curable liquid silicone adhesive (composition) was prepared by mixing 70 parts by mass of dimethylpolysiloxane having a viscosity of 30,000 mPa·s and having both molecular chain terminals capped with trimethoxysilyl groups, 40 parts by mass of dimethylpolysiloxane having a viscosity of 100 mPa·s and having both molecular chain terminals capped with trimethylsilyl groups, 80 parts by mass of aluminum hydroxide having an average particle size of 10 μm and an untreated surface (amount in the entire composition: 31.0% by mass), and a BET specific surface area of ​​17 m. 2 50 parts by mass of colloidal calcium carbonate having a molecular weight of 1 / g and a surface treated with a fatty acid, 8 parts by mass of vinyltrimethoxysilane, 2 parts by mass of a compound represented by the following formula (1), and 0.8 parts by mass of diisopropoxytitanium bis(ethylacetoacetate) were uniformly mixed to obtain Composition 1.

[0109] Composition Example 2: 85 parts by mass of dimethylpolysiloxane having both molecular chain terminals blocked with hydroxyl groups and a viscosity of 20,000 mPa·s, 15 parts by mass of dimethylpolysiloxane having both molecular chain terminals blocked with trimethylsilyl groups and a viscosity of 100 mPa·s, 70 parts by mass of aluminum hydroxide having an average particle size of 10 μm and an untreated surface (amount in the entire composition: 31.9% by mass), and a BET specific surface area of ​​2.0 m 2 / g, 30 parts by mass of ground calcium carbonate whose surface has been treated with paraffin, 120 parts by mass of ground calcium carbonate whose surface has been treated with dimethyldichlorosilane, and 2 Composition 2 was obtained by uniformly mixing 9 parts by mass of fumed silica having a molecular weight of 1 / g, 9.2 parts by mass of vinyltris(1-cyclopenten-1-yloxy)silane, 0.4 parts by mass of γ-(N,N,N',N'-tetramethylguanidyl)propyltrimethoxysilane, 0.4 parts by mass of the compound represented by the above formula (1), and 0.4 parts by mass of γ-aminopropyltriethoxysilane.

[0110] Composition Example 3 A composition containing 70 parts by mass of dimethylpolysiloxane having both molecular chain terminals blocked with trimethoxysilyl groups and a viscosity of 30,000 mPa·s, 40 parts by mass of dimethylpolysiloxane having both molecular chain terminals blocked with trimethylsilyl groups and a viscosity of 100 mPa·s, 80 parts by mass of aluminum hydroxide having an average particle size of 10 μm and an untreated surface (amount in the entire composition: 30.8% by mass), and a BET specific surface area of ​​17 m 2 Composition 3 was obtained by uniformly mixing 50 parts by mass of colloidal calcium carbonate having a molecular weight of 1 / g and a surface treated with a fatty acid, 2 parts by mass of iron powder having an average particle size of 30 μm (a content of which in the entire composition is 0.8% by mass), 8 parts by mass of vinyltrimethoxysilane, 2 parts by mass of the compound represented by the above formula (1), and 0.8 parts by mass of diisopropoxytitanium bis(ethylacetoacetate).

[0111] [Comparative Composition Example 1] 70 parts by mass of dimethylpolysiloxane whose molecular chain ends are capped with trimethoxysilyl groups and whose viscosity is 30,000 mPa·s, 40 parts by mass of dimethylpolysiloxane whose molecular chain ends are capped with trimethylsilyl groups and whose viscosity is 100 mPa·s, 5 parts by mass of fumed silica, and a BET specific surface area of ​​17 m 2 Composition 4 was obtained by uniformly mixing 50 parts by mass of colloidal calcium carbonate having a molecular weight of 1 / g and a surface treated with a fatty acid, 8 parts by mass of vinyltrimethoxysilane, 2 parts by mass of the compound represented by the above formula (1), and 0.8 parts by mass of diisopropoxytitanium bis(ethylacetoacetate).

[0112] [Composition Comparative Example 2] A composition containing 70 parts by mass of dimethylpolysiloxane having both molecular chain terminals blocked with trimethoxysilyl groups and a viscosity of 30,000 mPa·s, 40 parts by mass of dimethylpolysiloxane having both molecular chain terminals blocked with trimethylsilyl groups and a viscosity of 100 mPa·s, 100 parts by mass of aluminum hydroxide having an average particle size of 10 μm and an untreated surface (amount in the entire composition: 30.5% by mass), and a BET specific surface area of ​​17 m 2 Composition 5 was obtained by uniformly mixing 50 parts by mass of colloidal calcium carbonate having a molecular weight of 1 / g and a surface treated with a fatty acid, 50 parts by mass of iron powder having an average particle size of 30 μm (a content of which in the entire composition is 15.2% by mass), 8 parts by mass of vinyltrimethoxysilane, 2 parts by mass of the compound represented by the above formula (1), and 0.8 parts by mass of diisopropoxytitanium bis(ethylacetoacetate).

[0113] [Preparation of Bonding Member] A 25 mm wide, 50 mm long ADC12 (aluminum alloy die-cast) substrate and a 25 mm wide, 50 mm long PBT (polybutylene terephthalate resin, heat resistance temperature: 150°C or higher) substrate were used as the substrates, and any of the above Compositions 1 to 5 was used as the curable liquid silicone adhesive. Bonding thickness was 0.5 mm, and bonding area was 2.5 cm. 2 The ADC12 substrate and the PBT substrate were bonded together so that the bonded joint was in the range of 1 / 300 to 1 / 400 mm, and then cured at 23°C / 50% RH for 7 days to produce a bonded member bonded with a cured product of the curable liquid silicone adhesive (cured adhesive silicone rubber).

[0114] Evaluation of Dismantling Ease [Examples 1 to 3, Comparative Examples 1 and 2] The bonded members prepared above were evaluated by the following evaluation methods. The results are shown in Table 1, Figs. 1 and 2.

[0115] (1) Initial Adhesion Strength Using the bonded members prepared above, the shear adhesion strength was measured in accordance with the method specified in JIS K6850.

[0116] (2) Time to Disassembly EASYHEAT0224 manufactured by Aronix Co., Ltd. was used for electromagnetic induction heating. Electromagnetic induction heating was performed at a frequency of 286 kHz and an output of 2.3 kW, heating the metal portion of the bonding interface. Heating was continued until the bonded members were disassembled. The time required for disassembly was measured with a stopwatch, with a time of 15 seconds or less being considered a pass and a time of more than 15 seconds being considered a fail. For all compositions, the bonded members were disassembled by heating alone.

[0117] (3) State of the dismantled bonded surface after electromagnetic induction heating The state of the bonded surface of the dismantled ADC12 substrate was observed using a digital microscope VHX8000 manufactured by Keyence Corporation. The state before electromagnetic induction heating in Example 1 is shown in Figure 1, and the state after electromagnetic induction heating is shown in Figure 2. In addition, the remaining adhesive on the PBT substrate side was scraped off with a cutter knife, and the surface state was confirmed visually. The ADC12 substrate and the PBT substrate that showed no change in surface state before and after electromagnetic induction heating were considered to be no change.

[0118] (4) Adhesive strength after recycling The recyclability of the components disassembled by electromagnetic induction heating was confirmed. The ADC12 substrate was used as is, and the PBT substrate side had the adhesive scraped off with a cutter knife, then the adhesive was completely removed with a silicone decomposer (Silicone Cleaner X-100), washed with water, dried, and then used. The bonded components were prepared in the same manner as above. The shear adhesive strength was measured in accordance with the method specified in JIS K6850.

[0119]

[0120] As is clear from the above results, Examples 1 to 3, which are the method for dismantling bonded members of the present invention, were easily dismantled using electromagnetic induction heating in a short time of 12 to 14 seconds with little energy consumption, and were also recyclable. On the other hand, Comparative Example 1 was dismantled, but because no hydroxide compound was added, the effect of foaming to reduce adhesive strength was not achieved, and the time until dismantling was extended, but it was still recyclable. In Comparative Example 2, because 15.2% by mass of metal powder was added to the composition, the adhesive was also heated, causing the PBT substrate to melt, making it impossible to recycle.

Claims

1. A cured product obtained by curing a curable liquid silicone-based adhesive containing 25 to 80% by mass of a hydroxide compound having a decomposition temperature of 180 to 600°C and having a content of a material that generates heat by electromagnetic induction of 3% by mass or less, wherein a joining member in which at least a part of a joining interface is a metal and a plurality of members are joined together, and a step of separating the member containing the metal from among the members and disassembling the joining member by heating the metal portion of the joining interface by electromagnetic induction.

2. The method for disassembling a joining member according to claim 1, wherein the curable liquid silicone-based adhesive is a condensation-curing type liquid silicone-based adhesive, an addition reaction-curing type liquid silicone-based adhesive, or an ultraviolet-curing type liquid silicone-based adhesive.

3. The method for disassembling a joining member according to claim 1, wherein the hydroxide compound having a decomposition temperature of 180 to 600°C is at least one selected from aluminum hydroxide, magnesium hydroxide, and aluminum oxide hydroxide (boehmite).

4. The method for disassembling a joining member according to claim 1, wherein the frequency of electromagnetic induction heating is 100 kHz or more and 500 kHz or less.

5. The method for disassembling a joining member according to claim 1, wherein the joining member is an automotive part or an electric / electronic part.

6. An easily disassemblable condensation-curing type liquid silicone-based adhesive containing the following components (A) to (E) used in the method for disassembling a joining member according to any one of claims 1 to 5 and having a content of a material that generates heat by electromagnetic induction of 3% by mass or less. (A) A hydroxide compound having a decomposition temperature of 180 to 600°C: an amount that becomes 25 to 80% by mass of the entire adhesive, (B) A linear diorganopolysiloxane having a hydroxyl group and / or a hydrolyzable silyl group bonded to a silicon atom and having both ends of the molecular chain blocked: 100 parts by mass, (C) A hydrolyzable organosilane compound having three or more hydrolyzable groups bonded to a silicon atom in the molecule and / or a partial hydrolysis condensate thereof: 0.1 to 40 parts by mass, (D) A curing catalyst: 0.001 to 20 parts by mass, and (E) A silane coupling agent: 0.05 to 20 parts by mass.

7. An easily disassemblable addition reaction-curing type liquid silicone-based adhesive containing the following components (A) and (F) to (I) used in the method for disassembling a joining member according to any one of claims 1 to 5 and having a content of a material that generates heat by electromagnetic induction of 3% by mass or less. (A)Hydroxide compound with a decomposition temperature of 180 to 600 °C: in an amount that is 25 to 80% by mass of the total adhesive, (F)Alkenyl group-containing organopolysiloxane having an alkenyl group bonded to a silicon atom at the molecular chain end: 100 parts by mass, (G)Organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in the molecule: in an amount such that the silicon atom-bonded hydrogen atoms are 0.01 to 3 moles per mole of the alkenyl group bonded to a silicon atom in the (F) component, (H)Platinum group metal catalyst: 0.01 to 1,000 ppm in terms of the mass of platinum group metal atoms based on the total amount of the (F) component and the (G) component, and (I)Adhesion-imparting agent: 0.05 to 20 parts by mass.

8. An easily decomposable ultraviolet-curable liquid silicone-based adhesive containing the following (A), (J), and (K) components used in the method for disassembling the joint member according to any one of Claims 1 to 5, and having a content of the material that generates heat by electromagnetic induction of 3% by mass or less. (A)Hydroxide compound with a decomposition temperature of 180 to 600 °C: in an amount that is 25 to 80% by mass of the total adhesive, (J)Ultraviolet-reactive organopolysiloxane: 100 parts by mass, and (K)Photopolymerization initiator: 0.01 to 10 parts by mass.