Method for disassembling a joint member and easily disassembling liquid silicone-based adhesive

Abstract

A joining member that joins a plurality of members each of which includes at least a portion of a joining interface that is metal, with a cured product of a curable liquid silicone-based adhesive that contains 25 to 80 mass% of a hydroxylated compound having a decomposition temperature of 180 to 600°C and a content of a material that generates heat by electromagnetic induction of 3 mass% or less, is exposed to room temperature or further to a high temperature of about 150°C, and also exhibits sealing properties, and by heating the metal portion of the joining interface using electromagnetic induction, the joining member can be easily disintegrated in a short time and with little energy consumption, and the disintegrated members can be reused.

Description

Technical Field

[0001] This invention relates to a method for disassembling a bonded component using a curable liquid silicone adhesive, which enables the easy recycling, repair, and reuse of automotive parts, electrical and electronic products, etc., in a short time, and to the easily disassembleable liquid silicone adhesive used in this method. Background Technology

[0002] In recent years, the need for reusability has increased across various sectors due to environmental friendliness and cost reduction. Reuse is now prevalent in industries such as automotive and electrical / electronics, necessitating the disassembly of components within joints. Furthermore, joints play a crucial role in preventing the intrusion of external dust and moisture and protecting internal components, thus requiring reliable sealing performance. Adhesive-based seals offer the best sealing performance, and maintaining adhesion under various conditions (heat resistance, moisture resistance, etc.) is essential. Therefore, cured materials typically adhere firmly to the substrate, making removal of joints difficult.

[0003] As a method for reusing bonded components using curable resin compositions, for example, Japanese Patent Application Publication No. 2003-026784 (Patent Document 1) proposes to disassemble the components bonded together by heating the bonded component made using a polyol-based curable composition to 150-200°C, thereby softening or liquefying it. Additionally, Japanese Patent Application Publication No. 2002-327163 (Patent Document 2) proposes to disassemble the components of an adhesive structure by contacting the adhesive portion of an adhesive structure using a moisture-curing adhesive with a urethane prepolymer as the main component with a halogen-based organic solvent, thereby reducing the adhesive strength of the adhesive portion and then peeling it off from the adhesive portion. Furthermore, Japanese Patent Application Publication No. 2008-120903 (Patent Document 3) proposed a re-peelable desensitizing adhesive tape, which uses an adhesive composed of a mixture of vinyl monomers with alkyl (meth)acrylate as the main component. This adhesive maintains high normal adhesion during bonding, and when the bonded parts are separated or disassembled, the adhesion is reduced by heating, allowing for easy separation and disassembly. Moreover, Japanese Patent Publication No. 6221630 (Patent Document 4) proposed a method that incorporates a pressure-sensitive adhesive resin into an olefin polymer, enabling reprocessing and rebonding after reprocessing while maintaining sealing performance.

[0004] On the other hand, silicone-based adhesives and sealants exhibit superior heat resistance and weather resistance compared to the aforementioned organic adhesives, leading to their widespread use in the automotive, electrical and electronic, and construction industries. However, even when heated, silicone-based adhesives and sealants are difficult to decompose, resulting in challenges in repair and reuse.

[0005] Mask silicone adhesives have been proposed as a type of silicone adhesive that facilitates disassembly between components and provides a seal. Mask silicone adhesives without adhesive additives include those with release agents to impart release properties to glass and metal. However, in high-temperature durability tests exceeding 200°C, the release agent in such silicone adhesives undergoes thermal decomposition, losing its effectiveness. The components and silicone adhesive are then bonded by heat, making disassembly, recycling, and repair difficult.

[0006] Therefore, in applications where silicone adhesives are used for bonding, there is a need for reusable bonding components and methods for disassembling them.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2003-026784

[0010] Patent Document 2: Japanese Patent Application Publication No. 2002-327163

[0011] Patent Document 3: Japanese Patent Application Publication No. 2008-120903

[0012] Patent Document 4: Japanese Patent No. 6221630

[0013] Patent Document 5: Japanese Patent Application Publication No. 2022-183437

[0014] Patent Document 6: Japanese Patent Application No. 2021-160447 Summary of the Invention

[0015] The problem that the invention aims to solve

[0016] The present invention was made in view of the above-mentioned actual situation, and aims to provide a method for disassembling a joint member in which the adhesive component is a silicone-based adhesive, which maintains sealing performance after exposure at room temperature (23°C ± 15°C) or even at high temperatures of around 150°C, and can be easily reused in a short time and with low energy consumption, and an easily disassembleable liquid silicone-based adhesive used in the method for disassembling the joint member.

[0017] Methods for solving problems

[0018] To achieve the above-mentioned objective, the inventors proposed a method in Japanese Patent Application No. 2022-183437 (Japanese Patent Application No. 2021-090750) (Patent Document 5): Aluminum hydroxide, which decomposes at around 160°C, is mixed in a specific proportion into a curable liquid silicone adhesive. This results in bonded components that maintain sealing properties even after exposure to room temperature or even high temperatures around 150°C. Exposure to temperatures above 160°C reduces the sealing properties, making separation between components easier. However, this method uses a heating furnace and involves prolonged heating for several hours, resulting in high energy consumption.

[0019] Furthermore, Japanese Patent Application No. 2021-160447 (Patent Document 6) discloses a method for easily separating multiple components by irradiating them with microwaves. This method involves using a curable liquid silicone adhesive containing microwave-heated particles and a hydroxide compound with a decomposition temperature of 180–600°C to bond multiple components together. However, even this method requires several minutes, and a shorter separation time is desired.

[0020] Therefore, the inventors conducted in-depth research on bonding components with lower energy consumption and short-term reuse, and their disassembly methods. The results showed that, in order to improve the efficiency and energy conservation of recycling, repair, and reuse operations for automotive parts, electrical and electronic products, etc., a bonding component formed by bonding multiple components, including components with at least a metal interface, using a cured product made by curing a curable liquid silicone adhesive, maintains sealing properties even after exposure to room temperature, or even high temperatures of around 150°C. Simultaneously, by heating the metal portion of the bonding interface using electromagnetic induction, the bonding component can be easily disassembled within the bonding component in a short time with minimal energy consumption, allowing for reuse of the disassembled component. The curable liquid silicone adhesive contains 25-80% by mass of a hydroxide compound (particularly a metal hydroxide or a metal oxide hydroxide) with a decomposition temperature of 180-600°C, and the content of the material used for electromagnetic induction heating is less than 3% by mass. This invention thus completes the present invention.

[0021] Therefore, the present invention provides a method for disassembling the following bonding components and an easily disassembleable liquid silicone adhesive.

[0022] [1] A method for dismantling a joint component, comprising the following steps: for a joint component in which a plurality of components comprising at least a portion of a metal interface are joined by a cured product formed by curing a curable liquid silicone adhesive, the metal portion of the interface is heated by electromagnetic induction, thereby separating the metal components within these components to dismantle the joint component, wherein the curable liquid silicone adhesive contains 25 to 80% by mass of a hydroxide compound having a decomposition temperature of 180 to 600°C, and the content of the material heated by electromagnetic induction is 3% by mass or less.

[0023] [2] According to the disassembly method of the joint member described in [1], 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.

[0024] [3] The disassembly method of the joint member according to [1] or [2], wherein the hydroxide compound with a decomposition temperature of 180 to 600°C is at least one selected from aluminum hydroxide, magnesium hydroxide and aluminum oxide hydroxide (boehmite).

[0025] [4] The disassembly method of the joint member 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.

[0026] [5] The disassembly method of the joint member according to any one of [1] to [4], wherein the joint member is an automotive part or an electrical and electronic part.

[0027] [6] A condensation-curing liquid silicone adhesive with easy disintegration properties, containing the following components (A) to (E) for the disintegration method of the joint member according to any one of [1] to [5], wherein the content of the material used for electromagnetic induction heating is 3% by mass or less.

[0028] (A) Hydroxide compounds with a decomposition temperature of 180–600°C: their amount constitutes 25–80% by mass of the total adhesive.

[0029] (B) A linear organopolysiloxane whose molecular chain is capped at both ends with hydroxyl groups and / or hydrolyzable silanes bonded to silicon atoms: 100 parts by weight.

[0030] (C) Hydrolyzable organosilane compounds and / or their partial hydrolyzable condensates having three or more hydrolyzable groups bonded to silicon atoms in the molecule: 0.1–40 parts by mass.

[0031] (D) Curing catalyst: 0.001–20 parts by weight, and

[0032] (E) Silane coupling agent: 0.05 to 20 parts by weight.

[0033] [7] An addition-reaction curing liquid silicone adhesive with easy disintegration properties, containing the following components (A) and (F) to (I) for the disintegration method of the joint member according to any one of [1] to [5], wherein the content of the material used for electromagnetic induction heating is 3% by mass or less.

[0034] (A) Hydroxide compounds with a decomposition temperature of 180–600°C: their amount constitutes 25–80% by mass of the total adhesive.

[0035] (F) Alkenyl-containing organopolysiloxanes with alkenyl groups bonded to silicon atoms at the ends of the molecular chains: 100 parts by mass.

[0036] (G) An organohydrogen polysiloxane having at least two hydrogen atoms bonded to silicon atoms in its molecule: in such amounts that, relative to 1 mole of alkenyl groups bonded to silicon atoms in component (F), the number of hydrogen atoms bonded to silicon atoms is 0.01 to 3 moles.

[0037] (H) Platinum group metal catalysts: 0.01–1000 ppm relative to the combined stoichiometry of components (F) and (G), converted to mass of platinum group metal atoms.

[0038] (I) Adhesive agent: 0.05 to 20 parts by weight.

[0039] [8] An easily disintegrating UV-curable liquid silicone adhesive containing the following components (A) and (J), (K) for the disintegration method of the joint member according to any one of [1] to [5], wherein the content of the material using electromagnetic induction heating is 3% by mass or less.

[0040] (A) Hydroxide compounds with a decomposition temperature of 180–600°C: their amount constitutes 25–80% by mass of the total adhesive.

[0041] (J) UV-reactive organopolysiloxanes: 100 parts by weight, and

[0042] (K) Photopolymerization initiator: 0.01 to 10 parts by weight.

[0043] The effects of the invention

[0044] According to the method for dismantling the joint component of the present invention, the adhesiveness and / or sealing properties are achieved by applying a high temperature from room temperature to about 150°C, while electromagnetic induction heating is used to heat the metal portion of the joint interface, thereby indirectly heating the cured product of the curable liquid silicone adhesive that serves as the adhesive component. This reduces the adhesiveness and / or sealing properties, allowing the metal-containing component at the joint interface to be peeled off with a short time and low energy. Therefore, the joint component can be easily dismantled and reused. The curable liquid silicone adhesive used in this dismantling method can be used as an adhesive or sealant for joints requiring heat resistance and reusability.

[0045] Furthermore, in this invention, the so-called "heat resistance temperature" of a disintegrated component refers to the upper limit of the temperature at which the component does not undergo thermal decomposition or softening when left to stand at a specific temperature for one minute. Attached Figure Description

[0046] Figure 1 This image shows the surface state of the ADC12 substrate before electromagnetic induction heating, as observed using a digital microscope in Embodiment 1 of the present invention.

[0047] Figure 2 This image shows the surface state of the ADC12 substrate after electromagnetic induction heating, observed using a digital microscope in Embodiment 1 of the present invention. Detailed Implementation

[0048] The present invention will now be described in detail.

[0049] The method for dismantling the joint member of the present invention includes the following steps: for a joint member in which multiple members, including at least a portion of the joint interface being metal, are joined by curing a cured product formed by curing a curable liquid silicone adhesive, the metal portion of the joint interface is heated by electromagnetic induction, thereby separating the metal-containing members within these members to dismantle the joint member, wherein the curable liquid silicone adhesive contains 25 to 80% by mass of a hydroxide compound (particularly a metal hydroxide or a hydroxide of metal oxide) with a decomposition temperature of 180 to 600°C, and the content of the material heated by electromagnetic induction is 3% by mass or less.

[0050] [Curing liquid silicone adhesive]

[0051] The curable liquid silicone adhesive used in this invention is cured to form an adhesive component that bonds multiple components, including components whose interface is at least partly metallic. It is an adhesive containing a hydroxide compound (A) with a decomposition temperature of 180 to 600°C, a material that generates heat by electromagnetic induction with a content of 3% by mass or less, and a polymer whose main chain is composed of siloxane bonds as the base polymer. The preferred curing type is condensation curing type, addition reaction curing type, or ultraviolet curing type.

[0052] [A hydroxide compound with a decomposition temperature of 180–600℃]

[0053] Hydroxide compounds with a decomposition temperature of 180–600°C are generally preferred to be metal hydroxides or metal oxide hydroxides. Examples include aluminum hydroxide with a decomposition temperature around 180°C, magnesium hydroxide with a decomposition temperature around 300°C, and aluminum hydroxide (boehmite) with a decomposition temperature around 500°C. Furthermore, the term "decomposition temperature" refers to the temperature at which the hydroxide compound decomposes to begin producing water.

[0054] They begin to decompose when heated, producing water through this decomposition, which has an anti-inflammatory effect and has been used in flame-retardant materials in the past. In this invention, the water produced through this decomposition reduces the adhesive strength due to air bubbles generated in the cured liquid silicone adhesive, thereby making the disassembly of the joint components quick and easy.

[0055] As a hydroxide compound with a decomposition temperature of 180–600°C, a particulate hydroxide compound with an average particle size of 50 μm or less, preferably 0.5–20 μm, is used. If the average particle size is larger than 50 μm, the decomposability decreases. It should be noted that the average particle size can be determined as the cumulative weight average value D50 (or median diameter) using a particle size distribution measuring device employing laser diffraction or similar methods.

[0056] The surface of this hydroxide compound may be untreated or surface-treated (hydrophobicated). In the case of surface treatment, treatment agents are typically used, such as silane coupling agents and fatty acids. Surface treatment can be carried out using known methods. The amount treated is not particularly limited, but is preferably 3% by mass or less (typically 0.1% to 3% by mass), particularly preferably 0.2% to 2% by mass.

[0057] Furthermore, a single hydroxide compound can be used alone, or two or more hydroxide compounds with different average particle sizes and surface treatment methods can be used together.

[0058] The content of the hydroxide compound is 25-80% by mass of the curing liquid silicone adhesive, preferably 30-70% by mass, and more preferably 35-65% by mass. If it is less than 25% by mass, the decomposition (foaming) of the hydroxide compound is insufficient, and the disintegration is reduced. If it is more than 80% by mass, the viscosity of the composition increases, and the dischargeability during mixing and application deteriorates.

[0059] Materials that generate heat through electromagnetic induction

[0060] Examples of materials that utilize electromagnetic induction for heating include metallic materials, carbon fibers, carbon black, and other carbon materials. Examples of metallic materials used in curable liquid silicone adhesives include aluminum powder, iron powder, copper powder, and their alloy powders.

[0061] The curable liquid silicone adhesive used in this invention is designed to be as free of materials that generate heat through electromagnetic induction as possible. Even when additives such as colorants, which are optional components, contain materials that generate heat through electromagnetic induction, their proportion in the curable liquid silicone adhesive is 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, the disintegration resistance decreases.

[0062] The electromagnetic induction heating used in this invention can heat conductive metallic materials and carbon materials (e.g., carbon fiber, graphite, carbon black, etc.). On the other hand, in the case of this invention, by utilizing electromagnetic induction to heat the bonding interface portion of the metal used in the bonding member, efficient and short-time peeling can occur. However, if a material utilizing electromagnetic induction heating is added to the adhesive itself, the energy of electromagnetic induction is also used to heat the bonding member (the cured adhesive), thus reducing the likelihood of disintegration. Furthermore, when organic resin is used in the member, heating the bonding member can heat the organic resin in contact with the bonding member to above its heat resistance, causing the organic resin to melt and decompose, making the member unsuitable for reuse. Therefore, it is preferable to avoid adding materials utilizing electromagnetic induction heating (set to 3% by mass or less) to the curable liquid silicone adhesive of this invention.

[0063] [Condensation-curing liquid silicone adhesive]

[0064] Condensation-curing liquid silicone adhesives are liquid silicone adhesives that are cured by hydrolysis and condensation reactions caused by atmospheric moisture (humidity) at room temperature. In addition to the above-mentioned (A) hydroxide compound with a decomposition temperature of 180-600°C, they also contain (B) a linear diorganopolysiloxane (base polymer) whose molecular chain is capped at both ends by hydroxyl groups and / or hydrolyzable silanes bonded to silicon atoms, (C) a hydrolyzable organosilane compound and / or its partial hydrolyzable condensate (crosslinking agent) having three or more hydrolyzable groups bonded to silicon atoms in the molecule, (D) a curing catalyst, and (E) a silane coupling agent (adhesive imparting agent).

[0065] As a condensation-curing type liquid silicone adhesive, it preferably contains:

[0066] (A) Hydroxide compounds with a decomposition temperature of 180–600°C: their amount constitutes 25–80% by mass of the total adhesive.

[0067] (B) A linear organopolysiloxane whose molecular chain is capped at both ends with hydroxyl groups and / or hydrolyzable silanes bonded to silicon atoms: 100 parts by weight.

[0068] (C) Hydrolyzable organosilane compounds and / or their partial hydrolyzable condensates having three or more hydrolyzable groups bonded to silicon atoms in the molecule: 0.1–40 parts by mass.

[0069] (D) Curing catalyst: 0.001–20 parts by weight, and

[0070] (E) Silane coupling agent: 0.05–20 parts by weight,

[0071] Furthermore, it is a condensation-curing liquid silicone adhesive with a content of less than 3% by mass of materials that utilize electromagnetic induction for heating.

[0072] (B) The organopolysiloxane used as the base polymer (main agent) is a linear diorganopolysiloxane with both ends of the molecular chain capped with hydroxyl groups (silanol groups) and / or hydrolyzable silyl groups bonded to silicon atoms. Preferably, the hydrolyzable silyl group is an alkoxysilyl group or an alkoxy-substituted alkoxysilyl group.

[0073] In the case of having hydroxyl groups (silanol groups) bonded to silicon atoms, there may be a hydroxyl group (i.e., hydroxymethylsilyl or silanol group) bonded to silicon atoms at each end of the molecular chain.

[0074] When the terminal has an alkoxysilyl or alkoxy-substituted alkoxysilyl as a hydrolyzable silyl, each of the two ends of the molecular chain may have 2 or 3 alkoxy groups bonded to silicon atoms (i.e., alkoxysilyl) or alkoxy-substituted alkoxy groups bonded to silicon atoms (i.e., alkoxyalkoxysilyl) (i.e., existing as a diekoxyorganosyl or bis(alkoxyalkoxy)organosyl, trialkoxysilyl or tri(alkoxyalkoxy)silyl).

[0075] As an alkoxy group, alkoxy groups with 1 to 10 carbon atoms, especially 1 to 4 carbon atoms, are preferred. Examples include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, hexoxy, octoxy, etc.

[0076] As an alkoxy-substituted alkoxy group, it is preferred to have alkoxy-substituted alkoxy groups with 2 to 10 carbon atoms, especially 2 to 4 carbon atoms, such as methoxyethoxy, ethoxyethoxy, methoxypropoxy, etc.

[0077] As a linear organopolysiloxane that caps both ends of the molecular chain with hydroxyl groups and / or hydrolyzable silyl groups bonded to silicon atoms, it is particularly preferred that the organopolysiloxane has hydroxyl (silanol), methoxy or ethoxy groups at both ends, preferably only at both ends.

[0078] As organic groups bonded to silicon atoms, excluding hydroxyl and hydrolyzable groups, examples include unsubstituted or substituted monovalent hydrocarbon groups with 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; and aralkyl groups such as benzyl, phenylethyl, and phenylpropyl. Groups formed by replacing some or all of the hydrogen atoms bonded to carbon atoms of these groups with halogen atoms such as fluorine, bromine, and chlorine, or with cyano groups, such as trifluoropropyl and chloropropyl haloalkyl groups; and cyanoalkyl groups such as β-cyanoethyl and γ-cyanopropyl. Methyl is preferred.

[0079] The viscosity of the organopolysiloxane as the base polymer (main agent) at 23°C is preferably 50–1,000,000 mPa·s, more preferably 100–300,000 mPa·s. If the viscosity is below the lower limit, sufficient mechanical properties may not be obtained in the resulting cured product. Furthermore, if the viscosity exceeds the upper limit, workability may decrease. In this invention, the viscosity is the value at 23°C measured using a rotational viscometer (e.g., BL type, BH type, BS type, cone-plate type, rheometer, etc.).

[0080] Organopolysiloxanes, which serve as the base polymer (main agent), can be used alone or in combination of two or more.

[0081] The hydrolyzable organosilane compound and / or its partially hydrolyzed condensate as (C) crosslinking agent (curing agent) is a hydrolyzable organosilane compound and / or its partially hydrolyzed condensate having three or more hydrolyzable groups bonded to silicon atoms in the molecule (i.e., siloxane oligomers and other siloxane compounds having three or more residual hydrolyzable groups in the molecule). Component (C) functions as a crosslinking agent (curing agent) that forms a crosslinked structure by hydrolysis and condensation reaction between a linear diorganopolysiloxane, which has three or more hydrolyzable groups in the molecule and is capped at both ends of the molecular chain by hydroxyl groups and / or hydrolyzable silyl groups bonded to silicon atoms, as the base polymer described above.

[0082] Hydrolyzable groups in hydrolyzable organosilane compounds include alkoxy groups, alkoxy-substituted alkoxy groups, acyloxy groups, alkenyloxy groups, ketoxime groups, aminooxy groups, and amide groups with 1 to 10 carbon atoms. Examples include alkoxy groups such as methoxy, ethoxy, and propoxy; alkoxy-substituted alkoxy groups such as methoxyethoxy, ethoxyethoxy, and methoxypropoxy; acyloxy groups such as acetoxy and octanoyloxy; alkenyloxy groups such as vinyloxy, isopropenyloxy, and 1-ethyl-2-methylvinyloxy; ketoxime groups such as dimethylketoxime, methylethylketoxime, and methylisobutylketoxime; aminooxy groups such as dimethylaminooxy and diethylaminooxy; and amide groups such as N-methylacetamido and N-ethylacetamido.

[0083] Hydrolyzable organosilane compounds may have organic groups bonded to silicon atoms other than the aforementioned hydrolyzable groups. Examples of such organic groups bonded to silicon atoms, other than hydrolyzable groups, 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 are replaced by halogen atoms such as fluorine, bromine, or chlorine, or by cyano groups, such as 3-chloropropyl and 3,3,3-trifluoropropyl halogenated alkyl groups. Among them, methyl, ethyl, propyl, vinyl, and phenyl are preferred as unsubstituted or substituted monovalent hydrocarbon groups.

[0084] Examples of hydrolyzable organosilane compounds and their partially hydrolyzed condensates include, for example, alkoxysilanes such as methyltrimethoxysilane, ethyltrimethoxysilane, decyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, vinyltri(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; and methyltris(methoxymethoxy)silane, ethyltris(methoxymethoxy)silane, and vinyltris(methoxymethoxy)silane. Alkoxy-substituted alkoxysilanes such as phenyltris(methoxymethoxy)silane, methyltris(ethoxymethoxy)silane, ethyltris(ethoxymethoxy)silane, vinyltris(ethoxymethoxy)silane, phenyltris(ethoxymethoxy)silane, tetra(methoxymethoxy)silane, and tetra(ethoxymethoxy)silane; aminooxysilanes such as methyltris(N,N-diethylaminooxy)silane; acylaminosilanes such as methyltris(N-methylacetamido)silane, methyltris(N-butylacetamido)silane, and methyltris(N-cyclohexylacetamido)silane; olefinic silanes such as methyltriisopropoxysilane, vinyltriisopropoxysilane, and phenyltriisopropoxysilane; acyloxysilanes such as methyltriacetamidosilane and vinyltriacetamidosilane; and partially hydrolyzed condensates of these hydrolyzable organosilane compounds.

[0085] Hydrolyzable organosilane compounds, which act as crosslinking agents (curing agents), do not have monovalent hydrocarbon groups in their molecules that are replaced by functional groups with heteroatoms such as nitrogen, oxygen, and sulfur atoms, which is clearly different from (E) silane coupling agents, which are adhesive imparting agents, as described later.

[0086] Hydrolyzable organosilane compounds and / or their partially hydrolyzed condensates may be used alone or in combination of two or more.

[0087] The amount of the hydrolyzable organosilane compound and / or its partially hydrolyzed condensate as a crosslinking agent (curing agent) is 0.1 to 40 parts by mass, preferably 1 to 20 parts by mass, relative to 100 parts by mass of a linear diorganopolysiloxane whose molecular chain is capped at both ends by hydroxyl groups bonded to silicon atoms and / or hydrolyzable silyl groups. If the amount of the hydrolyzable organosilane compound and / or its partially hydrolyzed condensate is less than the above-mentioned lower limit (0.1 parts by mass), it may result in a decrease in curability and shelf life. In addition, if it exceeds the above-mentioned upper limit (40 parts by mass), not only does it become price-disadvantageous, but the elongation of the cured product may also decrease, or the durability may be reduced.

[0088] (D) The curing catalyst can be a condensation catalyst that is conventionally used as a curing accelerator for condensation-curing liquid silicone adhesives (room temperature curing organopolysiloxane compositions). Examples include organotin compounds such as dibutylmethoxytin, dibutyltin diacetate, dibutyltin dioctanoate, dibutyltin dilaurate, dioctyltin dioctanoate, dioctyltin dioctanoate, dioctyltin dinedecanoate, dimethyl dimethoxytin, and dimethyltin diacetate; organotitanium compounds such as tetrapropyl titanate, tetrabutyl titanate, tetra-2-ethylhexyl titanate, diisopropoxytitanium bis(ethyl acetoacetate), and dimethoxydiacetylacetonate; amine compounds such as hexylamine and tetramethylguanidylpropyltrimethoxysilane, and their salts. One of these compounds can be used alone or in combination of two or more.

[0089] Regarding the amount of curing catalyst, relative to 100 parts by mass of a linear organopolysiloxane whose molecular chain is capped at both ends by hydroxyl groups bonded to silicon atoms and / or hydrolyzable silanes, the amount 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. If the amount of curing catalyst is less than the lower limit (0.001 parts by mass), catalytic effect may not be obtained. In addition, if the amount of curing catalyst exceeds the upper limit (20 parts by mass), not only does it become unfavorable in terms of price, but the durability of the composition may also decrease, or the adhesion may decrease.

[0090] In condensation-curing liquid silicone adhesives, a silane coupling agent (a hydrolyzable silane compound having a monovalent hydrocarbon group replaced by a functional group having heteroatoms such as nitrogen, oxygen, and sulfur atoms (but excluding guanidine groups)) is added as component (E) to improve adhesive strength and act as an adhesive-imparting component.

[0091] The silane coupling agent used as the adhesive-imparting component is preferably a silane coupling agent known in the art. In particular, as the hydrolyzable group, a group having an alkoxy or alkenoxy group is preferred; specifically, examples include alkoxy groups such as methoxy, ethoxy, and propoxy, and alkenoxy groups such as isopropoxy and 1-ethyl-2-methylethoxy.

[0092] Furthermore, as a monovalent hydrocarbon group substituted with a functional group having heteroatoms such as nitrogen, oxygen, and sulfur (however, excluding guanidine), it is preferable to have a monovalent hydrocarbon group having 1 to 20 carbon atoms having at least one unsubstituted or substituted amino group, unsubstituted or substituted imino group, mercapto group, epoxy group, (meth)acryloyloxy group, etc. Specific examples include γ-acryloyloxypropyl, γ-methacryloyloxypropyl, β-(3,4-epoxycyclohexyl)ethyl, γ-glycidoxypropyl, N-β(aminoethyl)γ-aminopropyl, γ-aminopropyl, and the following formulas.

[0093] [Chemistry 1]

[0094]

[0095] The groups represented are γ-mercaptopropyl, etc.

[0096] Silane coupling agents may have organic groups other than monovalent hydrocarbon groups substituted with the aforementioned hydrolyzable and functional groups that are bonded to silicon atoms. As organic groups other than monovalent hydrocarbon groups substituted with such hydrolyzable and functional groups that are bonded to silicon atoms, monovalent hydrocarbon groups having 1 to 10 carbon atoms are preferred. Examples include 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. Methyl and ethyl groups are preferred.

[0097] As silane coupling agents, examples specifically include γ-acryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and those derived from the following formulas.

[0098] [Chemistry 2]

[0099]

[0100] The examples include silane compounds such as γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltriisopropoxysilane, and γ-glycidoxypropylmethyldiisopropoxysilane. Silane coupling agents containing amino groups are particularly preferred.

[0101] Silane coupling agents can be used alone or in combination of two or more.

[0102] The amount of silane coupling agent in component (E) 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, relative to 100 parts by mass of a linear organopolysiloxane whose molecular chain is capped by hydroxyl groups and / or hydrolyzable silanes bonded to silicon atoms. If it is less than 0.05 parts by mass, sufficient adhesion will not be obtained; if it is more than 20 parts by mass, the weather resistance and mechanical properties of the cured product will be poor.

[0103] In condensation-curing liquid silicone adhesives, in addition to the above-mentioned components, optional components may be formulated without prejudice to the purpose of the present invention. Examples of such optional components include inorganic fillers, pigments, dyes, fluorescent whitening agents, and other colorants other than component (A); antibacterial agents; antifungal agents; plasticizers such as silicone oil (non-functional organopolysiloxane).

[0104] Inorganic fillers other than component (A) that can be used as optional components include, specifically, carbon such as acetylene black, dry silica (fumed silica, etc.), wet silica (precipitated silica, etc.), quartz micro powder, diatomaceous earth powder, particulate alumina, magnesium oxide powder, colloidal calcium carbonate, heavy calcium carbonate, and other calcium carbonate, and inorganic fillers in the form of micro powders that have been surface-treated with silanes, silazanes, low-polymerization-degree polysiloxanes, etc. (however, excluding component (A)).

[0105] When inorganic fillers other than component (A) are mixed, the mixing amount is preferably 0.1 to 800 parts by mass relative to 100 parts by mass of a linear diorganopolysiloxane whose molecular chain is capped at both ends by hydroxyl groups bonded to silicon atoms and / or hydrolyzable silyl groups. More preferably, it is 0.5 to 600 parts by mass.

[0106] Condensation-curing liquid silicone adhesives can be prepared by uniformly mixing the above-mentioned components using a known mixer in a moisture-free environment (dry atmosphere or under reduced pressure) according to conventional methods.

[0107] Furthermore, the obtained condensation-curing liquid silicone adhesive can be cured, for example, by being placed at room temperature (23℃±15℃). Its molding method, curing conditions, etc., can adopt known methods and conditions that are consistent with the type of condensation-curing liquid silicone adhesive. For example, it can be cured by being left to stand in the atmosphere for several hours to several days (e.g., 6 hours to 7 days) at 23℃ / 50%RH.

[0108] [Addition reaction curing type liquid silicone adhesive]

[0109] The addition reaction curing type liquid silicone adhesive is a liquid silicone adhesive that, in addition to the above-mentioned (A) hydroxide compound with a decomposition temperature of 180 to 600°C, also includes (F) an alkenyl-containing organopolysiloxane (basic polymer) having an alkenyl group such as vinyl bonded to silicon atoms at the end of the molecular chain, (G) an organohydrogen polysiloxane (crosslinking agent) having at least two hydrogen atoms (SiH group) bonded to silicon atoms in the molecule, (H) a platinum group metal catalyst (hydrosilane addition reaction catalyst), and (I) an adhesiveness imparting agent, and is crosslinked by the addition reaction of SiH group with vinyl group (hydrosilane reaction) to obtain a cured product.

[0110] As an addition reaction curing type liquid silicone adhesive, it preferably contains:

[0111] (A) Hydroxide compounds with a decomposition temperature of 180–600°C: their amount constitutes 25–80% by mass of the total adhesive.

[0112] (F) Alkenyl-containing organopolysiloxanes with alkenyl groups bonded to silicon atoms at the ends of the molecular chains: 100 parts by mass.

[0113] (G) An organohydrogen polysiloxane having at least two hydrogen atoms bonded to silicon atoms in its molecule: in an amount such that, relative to 1 mole of alkenyl groups bonded to silicon atoms in component (F), the number of hydrogen atoms bonded to silicon atoms is 0.01 to 3 moles.

[0114] (H) Platinum group metal catalysts: 0.01–1000 ppm relative to the combined stoichiometry of components (F) and (G), converted to mass of platinum group metal atoms.

[0115] (I) Adhesive agent: 0.05-20 parts by weight,

[0116] Furthermore, it utilizes an easily disintegrating addition reaction curing liquid silicone adhesive with a content of less than 3% by mass of materials that generate heat through electromagnetic induction.

[0117] The alkenyl-containing organopolysiloxane, which serves as the base polymer (main agent) in (F), is a linear diorganopolysiloxane whose molecular chain ends (single or double ends) are capped with silyl groups such as vinyl groups bonded to silicon atoms. It is an organopolysiloxane that has an average of at least one, preferably two or more (usually 2 to 20, particularly 2 to 10, and further approximately 2 to 5) alkenyl groups bonded to silicon atoms in the molecule. Examples of such alkenyl groups include, for example, lower alkenyl groups with 2 to 6 carbon atoms, preferably approximately 2 to 4 carbon atoms, such as vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, and cyclohexenyl. Furthermore, as long as the alkenyl-containing organopolysiloxane, which serves as the base polymer (main agent), has an alkenyl group bonded to silicon atoms at one or both ends of the molecular chain, it may also have an alkenyl group on the side chain of the molecular chain.

[0118] Furthermore, there are no particular limitations on the organic groups bonded to silicon atoms, except for alkenyl groups bonded to silicon atoms, as long as they do not have aliphatic unsaturated bonds. Examples include unsubstituted or substituted monovalent hydrocarbon groups with a carbon number of 1 to 12, preferably 1 to 10, and which do not contain aliphatic unsaturated bonds. 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; and aralkyl groups such as benzyl and phenethyl. Haloalkyl groups in which some or all of the hydrogen atoms of these groups are replaced by halogen atoms such as chlorine, fluorine, and bromine atoms, such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl, are preferred, especially alkyl and aryl groups, and more preferably methyl and phenyl groups.

[0119] Specific examples of organopolysiloxanes containing alkenyl groups include dimethylvinylsiloxy-terminated dimethyl polysiloxane, dimethylvinylsiloxy-terminated dimethylsiloxane-methyl vinylsiloxane copolymer, dimethylvinylsiloxy-terminated dimethylsiloxane-diphenylsiloxane copolymer, dimethylvinylsiloxy-terminated dimethylsiloxane-methyl vinylsiloxane-diphenylsiloxane copolymer, dimethylvinylsiloxy-terminated dimethyltrifluoropropyl polysiloxane, dimethylvinylsiloxy-terminated dimethylsiloxane-methyltrifluoropropylsiloxane copolymer, and dimethylvinylsiloxy-terminated dimethylsiloxane-methyltrifluoropropylsiloxane copolymer. Trifluoropropylsiloxane-methyl vinylsiloxane copolymer, dimethyl divinylsiloxy-terminated dimethyl polysiloxane, dimethyl divinylsiloxy-terminated dimethyl siloxane-methyl vinyl siloxane copolymer, dimethyl divinylsiloxy-terminated dimethyl siloxane-diphenyl siloxane copolymer, dimethyl divinylsiloxy-terminated dimethyl siloxane-methyl vinyl siloxane-diphenyl siloxane copolymer, dimethyl divinylsiloxy-terminated methyl trifluoropropyl polysiloxane, dimethyl divinylsiloxy-terminated dimethyl siloxane-methyl trifluoropropyl siloxane copolymer, dimethyl divinylsiloxy-terminated dimethyl siloxane-methyl trifluoropropyl siloxane copolymer Fluoropropylsiloxane-methylvinylsiloxane copolymer, dimethyl polysiloxane with two-terminated trivinylsiloxy groups, dimethyl polysiloxane-methyl vinylsiloxane-methyl vinylsiloxane copolymer, dimethyl polysiloxane-diphenylsiloxane-methyl vinylsiloxane-diphenylsiloxane copolymer, dimethyl polysiloxane-methyl trifluoropropylsiloxane-methyl trifluoropropylsiloxane copolymer, dimethyl polysiloxane-methyl trifluoropropylsiloxane-methyl vinylsiloxane-methyl vinylsiloxane copolymer Polymers, dimethyl polysiloxanes with one terminal trimethylsiloxy group and the other terminal dimethylvinylsiloxy group, dimethyl siloxane-methyl vinyl siloxane copolymers with one terminal trimethylsiloxy group and the other terminal dimethylvinylsiloxy group, dimethyl siloxane-diphenyl siloxane copolymers with one terminal trimethylsiloxy group and the other terminal dimethylvinylsiloxy group, dimethyl siloxane-methyl vinyl siloxane-diphenyl siloxane copolymers with one terminal trimethylsiloxy group and the other terminal dimethylvinylsiloxy group, and methyl trifluoropropyl polysiloxane with one terminal trimethylsiloxy group and the other terminal dimethylvinylsiloxy group.A copolymer of dimethylsiloxane-methyltrifluoropropylsiloxane with one terminal trimethylsiloxy group and the other terminal dimethylvinylsiloxy group, and a copolymer of dimethylsiloxane-methyltrifluoropropylsiloxane-methylvinylsiloxane with one terminal trimethylsiloxy group and the other terminal dimethylvinylsiloxy group, etc.

[0120] The viscosity of the alkenyl-containing organopolysiloxane as the base polymer (main agent) at 23°C is preferably 100 to 500,000 mPa·s, more preferably 700 to 100,000 mPa·s.

[0121] The alkenyl-containing organopolysiloxanes used as the base polymer (main agent) can be used alone or in combination of two or more.

[0122] The organohydrogen polysiloxane used as (G) crosslinking agent (curing agent) has, on average, at least 2, preferably at least 3, more preferably up to 500, further preferably up to 200, and particularly preferably up to 100 hydrogen atoms (SiH groups) bonded to silicon atoms in the molecule, and preferably does not have aliphatic unsaturated bonds in the molecule.

[0123] In this organohydrogen polysiloxane, there are no particular limitations on the organic groups bonded to silicon atoms other than the hydrogen atoms bonded to the silicon atoms. Examples include unsubstituted or substituted monovalent hydrocarbon groups, typically with 1 to 10 carbon atoms, preferably 1 to 6. Specific examples include groups that are the same as those exemplified as organic groups bonded to silicon atoms other than the alkenyl groups bonded to the silicon atoms in the description of organopolysiloxanes containing alkenyl groups, alkenyl groups such as vinyl and allyl, and preferably unsubstituted monovalent hydrocarbon groups without aliphatic unsaturated bonds such as alkyl and aryl groups, more preferably methyl and phenyl groups.

[0124] Regarding the number of silicon atoms in the molecule, organohydrogen polysiloxanes that are liquid at room temperature with approximately 2 to 300, particularly 3 to 150, and especially 4 to 100, are preferred. Furthermore, the hydrogen atoms bonded to the silicon atoms can be located at either the end of the molecular chain, the middle (non-end) of the molecular chain, or both. Additionally, the molecular structure of the organohydrogen polysiloxane can be linear, cyclic, branched, or a three-dimensional network. In this invention, the degree of polymerization (or the number of repetitions of the diorganosiloxane units constituting the main chain, as a measure of the number of silicon atoms in the molecule) can be determined, for example, by using toluene as an elution solvent, or by using the number-average degree of polymerization (or number-average molecular weight) converted from polystyrene in gel permeation chromatography (GPC) analysis.

[0125] Examples of organohydrogen polysiloxanes include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, tris(dimethylsiloxy)methylsilane, tris(dimethylsiloxy)phenylsilane, methylhydrocyclopolysiloxane, methylhydrosiloxane-dimethylsiloxane cyclic copolymer, bi-terminated trimethylsiloxy-terminated methylhydropolysiloxane, bi-terminated trimethylsiloxy-terminated dimethylsiloxane-methylhydrosiloxane copolymer, bi-terminated dimethylhydrosiloxy-terminated dimethylpolysiloxane, and bi-terminated dimethylhydrosiloxy-terminated dimethylsiloxane. -Methylhydrosiloxane copolymer, trimethylsiloxy-terminated methylhydrosiloxane-diphenylsiloxane copolymer, trimethylsiloxy-terminated methylhydrosiloxane-diphenylsiloxane-dimethylsiloxane copolymer, trimethylsiloxy-terminated methylhydrosiloxane-dimethylsiloxane-dimethylsiloxane copolymer, trimethylsiloxy-terminated methylhydrosiloxane-dimethylsiloxane-dimethylsiloxane copolymer, dimethylsiloxy-terminated methylhydrosiloxane-dimethylsiloxane-dimethylsiloxane-diphenylsiloxane copolymer, dimethylsiloxy-terminated methylhydrosiloxane-dimethylsiloxane-dimethylsiloxane copolymer, (CH3)2HSiO 1 / 2 Unit and (CH3)3SiO 1 / 2 unit and SiO 4 / 2 A copolymer composed of units, consisting of (CH3)2HSiO 1 / 2 unit and SiO 4 / 2 A copolymer composed of units, consisting of (CH3)2HSiO 1 / 2 unit and SiO 4 / 2 Unit and (C6H5)SiO 3 / 2 These include copolymers composed of units, and products in which some or all of the methyl groups in these exemplary compounds are replaced with other alkyl groups, phenyl groups, etc. Furthermore, the organohydrogen polysiloxane of component (G), which has at least two hydrogen atoms bonded to silicon atoms in its molecule, is distinctly different from the adhesive-improving agent of component (I) described later in that the organic groups bonded to silicon atoms other than the hydrogen atoms bonded to silicon atoms in its molecule do not have functional groups such as epoxy groups, alkoxysilyl groups, etc.

[0126] Organohydropolysiloxanes can be used alone or in combination of two or more.

[0127] The amount of organohydrogen polysiloxane added is as follows: relative to 1 mole of alkenyl group bonded to silicon atom in organohydrogen polysiloxane containing alkenyl group, the amount of hydrogen atom bonded to silicon atom (SiH group) is 0.01 to 3 moles, preferably 0.05 to 2.5 moles, more preferably 0.2 to 2 moles.

[0128] (H) Platinum group metal catalysts (hydrosilane addition reaction catalysts) are used as catalysts to promote the addition reaction of alkenyl groups bonded to silicon atoms in organopolysiloxanes with hydrogen atoms bonded to silicon atoms in organohydrosiloxanes. Known catalysts can be used in this platinum group metal catalyst. Specific examples include alcohol-modified products of platinum black, chloroplatinic acid, etc.; and platinum-based catalysts such as complexes of chloroplatinic acid with olefins, aldehydes, vinylsiloxanes, or alkynyl alcohols.

[0129] The amount of platinum group metal catalyst can be an effective amount, which can be appropriately increased or decreased according to the required curing rate. Relative to the total amount of alkenyl-containing organopolysiloxanes and organohydrosiloxanes, calculated in terms of the mass of platinum group metal atoms, it is typically 0.01 to 1000 ppm, preferably 0.1 to 500 ppm, and more preferably in the range of 1 to 300 ppm. If this amount is too high, the heat resistance of the resulting cured product may decrease.

[0130] (I) The component is an adhesive agent that imparts self-adhesiveness to the composition of the present invention. This self-adhesiveness is particularly favorable for metals and organic resins. As an ingredient (I), examples include organosilicon compounds containing functional groups such as organosilicones having at least one of the following functional groups: vinyl, alkenyl, (meth)acryloyloxy, silyl (SiH), epoxy, alkoxysilyl, carbonyl, and phenyl, preferably two or more; organosiloxanes having about 2 to 30 silicon atoms, preferably 4 to 20; and cyclic or linear organopolysiloxanes containing 1 to 4, preferably 1 to 2, 1 to 4, preferably 2 to 4, phenylene structures in one molecule, and containing at least one, preferably 2 to 4, functional groups (e.g., alkenyl, (meth)acryloyloxy) that can facilitate hydrosilylation addition reactions, and which may contain oxygen atoms in the molecule, and are non-silicon (i.e., do not contain silicon atoms in the molecule).

[0131] Specifically, as such component (I), in addition to the functionalized organoalkoxysilanes and functionalized organohydrogen polysiloxanes exemplified below, and the functionalized linear organohydrogen polysiloxanes exemplified below in which the total number of repetitions of the two functional siloxane units is any positive integer ranging from 3 to 28, bisphenol compounds (bisphenol F, bisphenol A, bisphenol AF, etc.) or their oligomers containing derivatives of which the hydroxyl groups at both ends of the molecular chain are replaced by alkenoxy or (meth)acryloyloxy groups to end-alkoxy groups are listed.

[0132] [Chemistry 3]

[0133]

[0134] [Chemistry 4]

[0135]

[0136] (I) The component can be used alone or in combination of two or more. From the perspective of adhesion to the substrate, it is preferred to use a combination of organosilicon compound and non-silicone organic compound.

[0137] The amount of component (I) is such that the composition of the present invention can obtain good self-adhesion to the substrate, especially metals and organic resins, relative to 100 parts by weight of component (F), for example, 0.05 to 20 parts by weight, more preferably 0.1 to 15 parts by weight, and particularly preferably 0.5 to 10 parts by weight. If it is less than 0.05 parts by weight, sufficient adhesion may not be obtained, and if it is more than 20 parts by weight, the weather resistance and mechanical properties of the cured product may be poor.

[0138] In addition to the above-mentioned components, optional components can be formulated without prejudice to the purpose of this invention. Examples of such optional components include reaction inhibitors, inorganic fillers (excluding hydroxide compounds with a decomposition temperature of 180 to 600°C, but excluding those of component (A)) that do not contain silicon-bonded hydrogen atoms (SiH groups) and silicon-bonded alkenyl groups, so-called non-functional silicone oils, heat-resistant additives, flame retardants, thixotropic agents, pigments, dyes, etc.

[0139] Addition reaction curing liquid silicone adhesives can be prepared by uniformly mixing the above-mentioned components using a known mixer and conventional methods.

[0140] In addition, the curing conditions for addition reaction curing liquid silicone adhesives can be set to 23–150°C, particularly 23–100°C, for 10 minutes to 8 hours, particularly 30 minutes to 5 hours.

[0141] [UV-curable liquid silicone adhesive]

[0142] In addition to the aforementioned (A) hydroxide compound with a decomposition temperature of 180–600°C, the UV-curable liquid silicone adhesive also contains (J) a UV-reactive organopolysiloxane (base polymer) and (K) a photopolymerization initiator. It is a liquid silicone adhesive that is cross-linked by UV irradiation to obtain a cured product.

[0143] As a UV-curable liquid silicone adhesive, it preferably contains:

[0144] (A) Hydroxide compounds with a decomposition temperature of 180–600°C: their amount constitutes 25–80% by mass of the total adhesive.

[0145] (J) UV-reactive organopolysiloxanes: 100 parts by weight, and

[0146] (K) Photopolymerization initiator: 0.01–10 parts by weight,

[0147] Furthermore, it is an easily disintegrating, UV-curable liquid silicone adhesive that utilizes electromagnetic induction heating material with a content of less than 3% by mass.

[0148] (J) The UV-reactive organopolysiloxane of component (J) is not particularly limited as long as it generally functions as a base polymer in UV-curable silicone compositions, but is preferably an organopolysiloxane having at least 2, more preferably 2 to 20, and particularly preferably 2 to 10 UV-reactive groups per molecule. The multiple UV-reactive groups present in this organopolysiloxane may be all the same or different.

[0149] Examples of UV-reactive groups include, for example, alkenyl groups such as vinyl, allyl, and propenyl; alkenyloxy groups such as ethoxy, allyloxy, propenyloxy, and isopropenyloxy; aliphatic unsaturated groups other than alkenyl groups such as acryloyl and methacryloyl; epoxy groups; and hydrosilyl groups. Preferably, acryloyl, methacryloyl, mercapto, epoxy, and hydrosilyl groups are listed. More preferably, acryloyl and methacryloyl groups are listed.

[0150] Furthermore, there are no particular limitations on the organic groups bonded to silicon atoms, except for those bonded to alkenyl groups by silicon atoms, as long as they do not have aliphatic unsaturated bonds. Examples include unsubstituted or substituted monovalent hydrocarbon groups with a carbon number of 1 to 12, preferably 1 to 10, and which do not contain aliphatic unsaturated bonds. 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; and aralkyl groups such as benzyl and phenethyl. Haloalkyl groups in which some or all of the hydrogen atoms of these groups are replaced by halogen atoms such as chlorine, fluorine, and bromine atoms, such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl, are preferred, especially alkyl and aryl groups, and more preferably methyl and phenyl groups.

[0151] Specific examples of organopolysiloxanes containing ultraviolet-reactive groups include dimethylvinylsiloxy-terminated dimethylpolysiloxanes, dimethylvinylsiloxy-terminated dimethylsiloxane-methylvinylsiloxane copolymers, dimethylvinylsiloxy-terminated dimethylsiloxane-diphenylsiloxane copolymers, dimethylacryloylsiloxy-terminated dimethylpolysiloxanes, dimethylacryloylsiloxy-terminated dimethylsiloxane-methylvinylsiloxane copolymers, dimethylacryloylsiloxy-terminated dimethylsiloxane-diphenylsiloxane copolymers, and dimethylmethacryloyl-terminated dimethylsiloxanes. Siloxy-terminated dimethyl polysiloxane, dimethylmethacryloylsiloxy-terminated dimethyl siloxane-methyl vinyl siloxane copolymer, dimethylmethacryloylsiloxy-terminated dimethyl siloxane-diphenyl siloxane copolymer, dimethyl mercaptosiloxy-terminated dimethyl polysiloxane, dimethyl mercaptosiloxy-terminated dimethyl siloxane-methyl vinyl siloxane copolymer, dimethyl mercaptosiloxy-terminated dimethyl siloxane-diphenyl siloxane copolymer, dimethyl epoxysiloxy-terminated dimethyl polysiloxane, dimethyl epoxysiloxy-terminated dimethyl siloxane-methyl vinyl siloxane Siloxane copolymers, dimethylepoxysiloxane-dimethylsiloxane-diphenylsiloxane copolymers (terminated with dimethylepoxysiloxane), dimethyldivinylsiloxane-dimethylpolysiloxane (terminated with dimethyldivinylsiloxane), methylvinylsiloxane-methylvinylsiloxane copolymers (terminated with dimethyldivinylsiloxane), dimethyldivinylsiloxane-dimethylsiloxane-diphenylsiloxane copolymers (terminated with dimethyldiacryloylsiloxane), dimethyldiacryloylsiloxane-dimethylpolysiloxane (terminated with dimethyldiacryloylsiloxane), methylvinylsiloxane-methylvinylsiloxane copolymers (terminated with dimethyldiacryloylsiloxane), dimethyldiacryloylsiloxane-dimethylsiloxane-diphenylsiloxane copolymers (terminated with dimethyldiacryloylsiloxane). Dimethyl polysiloxanes with two ends of trivinylsiloxy group, dimethyl polysiloxane-methyl vinyl siloxane copolymers with two ends of trivinylsiloxy group, dimethyl polysiloxane-methyl vinyl siloxane copolymers with two ends of trivinylsiloxy group, dimethyl polysiloxane-methyl vinyl siloxane copolymers with one end of trivinylsiloxy group and the other end of trivinylsiloxy group, dimethyl polysiloxane-methyl vinyl siloxane copolymers with one end of trivinylsiloxy group and the other end of trivinylsiloxy group, dimethyl polysiloxane-methyl vinyl siloxane copolymers with one end of trivinylsiloxy group and the other end of trivinylsiloxy group, dimethyl polysiloxane-diphenyl siloxane copolymers with one end of trivinylsiloxy group and the other end of trivinylsiloxy group, etc.

[0152] The viscosity of the UV-reactive organopolysiloxane at 23°C is preferably 100–500,000 mPa·s, more preferably 700–100,000 mPa·s.

[0153] UV-reactive organopolysiloxanes can be used alone or in combination of two or more.

[0154] The photopolymerization initiator of component (K) promotes the photopolymerization of the ultraviolet-reactive groups in component (J). There are no particular limitations on component (K). Specific examples include acetophenone, phenylacetone, benzophenone, xanthonol, fluorescein, 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-chloroxanthonol, 3,9-dichloroxanthonol, 3-chloro-8-nonylxanthonol, benzoin, benzoin methyl ether, benzoin butyl ether, bis(4-dimethylaminophenyl) ketone, benzylmethoxyacetal, 2-chloro... Thioxanone, diethyl acetophenone, 1-hydroxychlorophenyl ketone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-(4-(methylthio)phenyl)-2-morpholino-1-propanone, 2,2-dimethoxy-2-phenylacetophenone, diethoxyacetophenone, and 2-hydroxy-2-methyl-1-phenylprop-1-one, etc., preferably, from the viewpoint of high purity, benzophenone, 4-methoxyacetophenone, 4-methylbenzophenone, diethoxyacetophenone, 1-hydroxycyclohexylphenyl ketone, and 2-hydroxy-2-methyl-1-phenylprop-1-one, more preferably, diethoxyacetophenone, 1-hydroxycyclohexylphenyl ketone, and 2-hydroxy-2-methyl-1-phenylprop-1-one.

[0155] These photopolymerization initiators can be used alone or in combination of two or more.

[0156] There is no particular limitation on the amount of component (K) added, but it is preferably 0.01 to 10 parts by weight relative to 100 parts by weight of component (J), more preferably 0.1 to 3 parts by weight, and even more preferably 0.5 to 3 parts by weight. If the amount of component (K) added is within this range, it is easy to control the curing of the UV-curable liquid silicone adhesive.

[0157] UV-curable liquid silicone adhesives can also be used, including liquid silicone adhesives that are both UV-curable and condensation-curable, or liquid silicone adhesives that are both UV-curable and addition-curable.

[0158] The liquid silicone adhesive, which is both UV-curable and condensation-curable, uses the aforementioned (A) hydroxide compound with a decomposition temperature of 180–600°C, as well as the aforementioned components (B) and (J) as the base polymer, the aforementioned component (C) as the curing agent, the component having both UV-reactive and condensable substituents, the aforementioned component (D) as the condensation-curing catalyst, the aforementioned component (K) as the UV-curing catalyst, and the aforementioned component (E) as the adhesive-imparting component.

[0159] The liquid silicone adhesive, which is both UV-curable and addition-curable, uses the aforementioned (A) hydroxide compound with a decomposition temperature of 180–600°C, as well as the aforementioned (F) and (J) components as the base polymer, the aforementioned (G) component as the curing agent, the aforementioned (H) component as the addition-curing catalyst, the aforementioned (K) component as the UV-curing catalyst, and the aforementioned (I) component as the adhesive-imparting component.

[0160] UV-curable liquid silicone adhesives can be prepared by uniformly mixing the above-mentioned components using a known mixer and conventional methods.

[0161] UV-curable liquid silicone adhesives are cured by irradiation with ultraviolet light. There are no particular limitations on the UV irradiation conditions, but it is preferable to use a UV light-emitting diode with an emission wavelength of 365nm, achieving an illuminance of 5–500 mW / cm². 2 Preferably, it is 10–200 mW / cm 2 This results in a light intensity of 0.5–100 J / cm². 2 Preferably, it is 10–50 J / cm 2 .

[0162] [Jointing Components]

[0163] In the disassembly method of the joining member of the present invention, the joining member is formed by joining multiple (particularly two) members whose joining interface is at least partly metallic by means of a cured product (an adhesive member composed of cured adhesive silicone rubber) made by curing a cured product containing a specific amount of a hydroxide compound with a decomposition temperature of 180 to 600°C and a material that generates heat by electromagnetic induction at a content of 3% by mass or less. The members may be the same or different.

[0164] In this joining component, one joining component uses a component whose joining interface is at least partially metallic, and the other joining component uses a component selected from the same component (the same component whose joining interface is at least partially metallic), an organic resin component, and a metal component.

[0165] For a component whose joint interface is at least partially metallic, it is sufficient that at least the joint interface contains metal, or it may be entirely metallic. Furthermore, the metallic component at the joint interface need only be an area that is sufficiently heated by electromagnetic induction.

[0166] As components in which at least a portion of the joint interface is metal, examples include automotive parts and electrical and electronic components that use aluminum alloys such as A1050, A2017, A5052, A5083, A6061, and A1N30; aluminum alloy die castings such as ADC1, ADC3, ADC10, ADC12, and ADC14; carbon steel such as SPCC, SS400, and SAPH; stainless steel such as SUS304 and SUS430; and magnesium alloys such as AZ-91D and AM50A.

[0167] The metal components forming the interface, at least a portion of which are metallic, and the metal of the metallic components, can be either magnetic or non-magnetic materials, provided they are metals capable of generating heat through electromagnetic induction. Examples include pure metals such as aluminum, iron, and copper, as well as alloys containing them (aluminum alloys (Al-Cu-Si alloys (ADC12), etc., aluminum alloy die castings), carbon steel (SPCC, SS400, SAPH, etc.), cast iron (Fe-Si-C ternary alloys), stainless steel (especially ferritic systems), copper alloys (brass, bronze, cupronickel), nickel-chromium alloys, magnesium alloys (AZ-91D, AM50A, etc.), titanium alloys, etc.). It should be noted that magnetic materials refer to metallic materials whose ratio of initial permeability (μ) to the permeability of vacuum (μ0), i.e., their relative permeability (μ / μ0), is 5 or higher, and further, 50 or higher.

[0168] Organic resins that constitute organic resin components include PBT (polybutylene terephthalate resin), PPS (polyphenylene sulfide resin), PA66 (nylon 66), PA6 (nylon 6) and other polyamide resins, PC (polycarbonate resin), etc.

[0169] Furthermore, in components that form at least a portion of the interface, such as metal components, organic resin components, or metal components, the aforementioned organic resin or metal preferably has a heat resistance temperature of 160°C or higher.

[0170] [Method for fabricating joining components]

[0171] A curable liquid silicone adhesive containing a hydroxide compound with a decomposition temperature of 180–600°C and a material that generates heat through electromagnetic induction, with a content of less than 3% by mass, is applied by hand or mechanical means to the surface of one side of a component in the shape of a joint (e.g., a gasket). Another component is then attached and joined together, and allowed to cure. It is then secured with bolts or similar fasteners as needed.

[0172] When the curable liquid silicone adhesive of the present invention is a condensation-curing type liquid silicone adhesive, it cures at room temperature using moisture in the air. Therefore, if multiple components are assembled and then placed, curing occurs. Humidification is effective when it is desired to increase the curing speed. Alternatively, when the curable liquid silicone adhesive of the present invention is an addition-reaction-curing type liquid silicone adhesive, it cures at a temperature of 23–150°C using an addition reaction. Therefore, if multiple components are assembled and then placed or heated, curing occurs. When the curable liquid silicone adhesive of the present invention is an ultraviolet-curing type liquid silicone adhesive, curing occurs by irradiating with ultraviolet light, thereby initiating a photopolymerization reaction and curing. Furthermore, if necessary, two curing cycles can be performed. The preferred temperature conditions for this are 120°C or higher, more preferably 150°C or higher, below the decomposition temperature of the hydroxide compound, and below 250°C. The preferred curing time is 10 minutes to 48 hours, more preferably 30 minutes to 24 hours.

[0173] Examples of the aforementioned connecting components include automotive parts such as engines, transmissions, automotive electrical components (ECUs (Electronic Control Units), PCUs (Power Control Units)), smartphones, tablet computers, LCDs, and batteries, with automotive parts and electrical components being preferred.

[0174] The above-mentioned joint components maintain their joint state at an ambient temperature of 150°C or below, preferably room temperature to 120°C.

[0175] The aforementioned bonding member is preferably a disintegrating bonding member that is bonded with a certain degree of adhesive force during normal use, and whose adhesive force decreases to the point where the member can be separated after electromagnetic induction heating. Specifically, the initial shear adhesive force of the aforementioned bonding member is preferably 1.2 MPa or more, particularly preferably 1.5 MPa or more, and the shear adhesive force of the bonding member after electromagnetic induction heating is preferably 1 MPa or less. This shear adhesive force is a value measured according to the method specified in JIS K6850. Furthermore, in order to make the initial and electromagnetic induction heating shear adhesive forces within the above-mentioned ranges, this can be achieved by making the composition of the curable liquid silicone adhesive within the above-mentioned specific range.

[0176] [Disassembly Method]

[0177] Regarding the method for disassembling the joining member of the present invention, the metal portion of the joining interface is indirectly heated to 160°C to 800°C by electromagnetic induction heating of the cured product (cured adhesive silicone rubber) formed by curing a curable liquid silicone adhesive, which serves as an adhesive member, in contact with the metal. As a result, the metal member naturally peels off within the joining member, or is peeled off by hand or with the help of a scraper or other tool, thereby enabling the joining member to be disassembled. Furthermore, the disassembled member can be reused.

[0178] It is presumed that the disintegration of the component according to the invention is possible for the following reasons.

[0179] The difference in the coefficients of linear expansion between the metal at the bonding interface and the bonded component is large. Therefore, if heated, a large thermal stress is applied to the bonding interface due to the difference in thermal expansion. Furthermore, in the case of bonding components made of dissimilar materials, thermal stress is also applied between the bonding components due to the difference in thermal expansion. Moreover, when the metal at the bonding interface is heated using electromagnetic induction, the hydroxide compound of component (A) in the cured product (cured adhesive silicone rubber) formed by curing a curable liquid silicone adhesive, which serves as the bonded component, is heated, decomposes to produce water, and then the produced water vaporizes, causing foaming and reducing the adhesive strength. As a result, the bonded component can disintegrate more quickly.

[0180] Regarding electromagnetic induction heating, the preferred parameters are the frequency, output power, and time, which enable component separation. The frequency can be selected within a range of 100kHz to 500kHz, and the output power can be selected within a range of 500W to 5kW. There is no particular limitation on the heating time using electromagnetic induction, but it is preferably 2 minutes or less, more preferably 1 minute or less, and more preferably 20 seconds or less.

[0181] Example

[0182] Secondly, examples of compositions, comparative examples of compositions, examples, and comparative examples are shown to specifically illustrate the present invention, but the present invention is not limited to the following examples. Furthermore, in the examples below, room temperature is 23°C, viscosity represents the value measured at 23°C using a rotational viscometer, and average particle size represents the value obtained as the cumulative weight average D50 (or median diameter) using a particle size distribution measuring device based on laser diffraction. BET specific surface area is the value calculated using the BET formula from the isothermal adsorption curve measured using the nitrogen adsorption method.

[0183] Preparation of curable liquid silicone adhesive (composition)

[0184] [Composition Example 1]

[0185] The composition comprises 70 parts by weight of dimethyl polysiloxane with a molecular chain end-capped with trimethoxysilyl and a viscosity of 30000 mPa·s, 40 parts by weight of dimethyl polysiloxane with a molecular chain end-capped with trimethoxysilyl and a viscosity of 100 mPa·s, 80 parts by weight of untreated aluminum hydroxide with an average particle size of 10 μm (content in the total composition is 31.0% by weight), and a BET specific surface area of ​​17 m². 2 / g, 50 parts by mass of colloidal calcium carbonate with surface treated with fatty acids, 8 parts by mass of vinyltrimethoxysilane, 2 parts by mass of the compound represented by the following formula (1), and 0.8 parts by mass of diisopropoxytitanium bis(ethyl acetoacetate) were uniformly mixed to obtain composition 1.

[0186] [Chemistry 5]

[0187]

[0188] [Composition Example 2]

[0189] The composition comprises 85 parts by weight of dimethyl polysiloxane with a molecular chain end-capped with hydroxyl groups and a viscosity of 20000 mPa·s, 15 parts by weight of dimethyl polysiloxane with a molecular chain end-capped with trimethylsilyl groups and a viscosity of 100 mPa·s, 70 parts by weight of untreated aluminum hydroxide with an average particle size of 10 μm (content in the total composition is 31.9% by weight), and a BET specific surface area of ​​2.0 m². 2 / g, 30 parts by weight of heavy calcium carbonate with paraffin-treated surface, and BET specific surface area of ​​120m² with dimethyldichlorosilane-treated surface 2 Composition 2 was obtained by uniformly mixing 9 parts by mass of fumed silica (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'-tetramethylguanidino)propyltrimethoxysilane, 0.4 parts by mass of the compound represented by the above formula (1), and 0.4 parts by mass of γ-aminopropyltriethoxysilane.

[0190] [Composition Example 3]

[0191] The composition comprises 70 parts by weight of dimethyl polysiloxane with a molecular chain end-capped with trimethoxysilyl and a viscosity of 30000 mPa·s, 40 parts by weight of dimethyl polysiloxane with a molecular chain end-capped with trimethoxysilyl and a viscosity of 100 mPa·s, 80 parts by weight of untreated aluminum hydroxide with an average particle size of 10 μm (content in the total composition is 30.8% by weight), and a BET specific surface area of ​​17 m². 2 / g, 50 parts by mass of colloidal calcium carbonate with surface treated with fatty acids, 2 parts by mass of iron powder with an average particle size of 30μm (content in the whole composition of 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(ethyl acetoacetate) were uniformly mixed to obtain composition 3.

[0192] [Comparative Example 1 of Compositions]

[0193] The following were prepared by combining 70 parts by mass of dimethyl polysiloxane with a molecular chain end-capped with trimethoxysilyl group and a viscosity of 30000 mPa·s, 40 parts by mass of dimethyl polysiloxane with a molecular chain end-capped with trimethoxysilyl group and a viscosity of 100 mPa·s, 5 parts by mass of fumed silica, and a BET specific surface area of ​​17 m². 2 / g, 50 parts by mass of colloidal calcium carbonate with surface treated with fatty acids, 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(ethyl acetoacetate) were uniformly mixed to obtain composition 4.

[0194] [Comparative Example 2 of Compositions]

[0195] The composition comprises 70 parts by weight of dimethyl polysiloxane with a molecular chain end-capped with trimethoxysilyl and a viscosity of 30000 mPa·s, 40 parts by weight of dimethyl polysiloxane with a molecular chain end-capped with trimethoxysilyl and a viscosity of 100 mPa·s, 100 parts by weight of untreated aluminum hydroxide with an average particle size of 10 μm (content in the total composition is 30.5% by weight), and a BET specific surface area of ​​17 m². 2 / g, 50 parts by mass of colloidal calcium carbonate with surface treated with fatty acids, 50 parts by mass of iron powder with an average particle size of 30μm (content in the whole 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(ethyl acetoacetate) were uniformly mixed to obtain composition 5.

[0196] [Fabrication of Joining Components]

[0197] As the substrate, ADC12 (aluminum alloy die-casting) with a width of 25mm and a length of 50mm and PBT (polybutylene terephthalate resin, heat resistance temperature: above 150°C) with a width of 25mm and a length of 50mm are used as substrates. As the curable liquid silicone adhesive, any one of the above compositions 1 to 5 is used, with an adhesive thickness of 0.5mm and an adhesive area of ​​2.5cm². 2By bonding an ADC12 substrate to a PBT substrate and aging it at 23°C / 50%RH for 7 days, a bonded component was produced by bonding a cured product of a curable liquid silicone adhesive (cured adhesive silicone rubber).

[0198] Evaluation of disintegration

[0199] [Examples 1-3, Comparative Examples 1 and 2]

[0200] The joint components fabricated as described above were evaluated using the evaluation method shown below. The results are presented in Table 1. Figure 1 , Figure 2 .

[0201] (1) Initial adhesion

[0202] Using the joint components prepared above, the shear bond strength was determined according to the method specified in JIS K6850.

[0203] (2) The time until disintegration

[0204] Alonics, Ltd.'s EASYHEAT 0224 was used in the electromagnetic induction heating. Electromagnetic induction heating was performed at a frequency of 286 kHz and an output of 2.3 kW, heating the metal portions of the joint interface until the joint component disintegrated. The time taken for disintegration was measured with a stopwatch; less than 15 seconds was considered acceptable, and more than 15 seconds was considered unacceptable. For all compositions, the joint component disintegrated solely through heating.

[0205] (3) The state of the disintegration joint surface under electromagnetic induction heating

[0206] The state of the bonding surface of the disassembled ADC12 substrate was observed using a VHX8000 digital microscope manufactured by KEYANCE Co., Ltd. The state before electromagnetic induction heating in Example 1 is shown below. Figure 1 The state after electromagnetic induction heating is shown in Figure 2 Furthermore, regarding the PBT substrate, the remaining adhesive was removed with a tool, and the surface condition was visually verified. Cases where the surface condition of both the ADC12 substrate and the PBT substrate remained unchanged before and after electromagnetic induction heating were recorded as unchanged.

[0207] (4) Adhesive strength after reuse

[0208] The reusability of components disassembled by electromagnetic induction heating was confirmed. ADC12 substrates were used directly. For PBT substrates, the adhesive was removed by cutting with a tool, then completely removed with a silicone degrader (silicone cleaner X-100), followed by washing and drying before use. Jointed components were fabricated using the same method. Shear bond strength was measured according to the method specified in JIS K6850.

[0209] [Table 1]

[0210]

[0211] As can be seen from the above results, the embodiments 1 to 3, which are the disassembly methods of the joining members of the present invention, can be easily disassembled in a short time of 12 to 14 seconds with little energy consumption by electromagnetic induction heating, and can then be reused.

[0212] On the other hand, although Comparative Example 1 could be disintegrated, the lack of added hydroxide compound prevented the reduction in adhesive strength due to foaming, and the disintegration time was prolonged, but it was still reusable. Comparative Example 2 also contained 15.2% by mass of metal powder, which, when heated, caused the PBT substrate to dissolve and was not reusable.

Claims

1. A method for dismantling a joint component, comprising the following steps: for a joint component formed by joining multiple components, at least a portion of which is metal, to a cured product obtained by curing a curable liquid silicone adhesive, heating the metal portion of the joint interface by electromagnetic induction, thereby separating the metal-containing components within these components to dismantle the joint component, wherein the curable liquid silicone adhesive contains 25-80% by mass of a hydroxide compound with a decomposition temperature of 180-600°C, and the content of the material heated by electromagnetic induction is 3% by mass or less.

2. The method for dismantling a joint member according to claim 1, wherein, Curing liquid silicone adhesives are condensation-curing liquid silicone adhesives, addition-reaction-curing liquid silicone adhesives, or UV-curing liquid silicone adhesives.

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

4. The method for dismantling a joint member according to claim 1, wherein, The frequency of electromagnetic induction heating is above 100kHz and below 500kHz.

5. The method for dismantling a joint member according to claim 1, wherein, The connecting components are automotive parts or electrical and electronic components.

6. A condensation-curing liquid silicone adhesive with easy disintegration properties, comprising the following components (A) to (E) for the disintegration method of the joint member according to any one of claims 1 to 5, wherein the content of the material used for electromagnetic induction heating is 3% by mass or less. (A) Hydroxide compounds with a decomposition temperature of 180–600°C: their amount constitutes 25–80% by mass of the total adhesive. (B) A linear organopolysiloxane whose molecular chain is capped at both ends with hydroxyl groups and / or hydrolyzable silanes bonded to silicon atoms: 100 parts by weight. (C) Hydrolyzable organosilane compounds and / or their partial hydrolyzable condensates having three or more hydrolyzable groups bonded to silicon atoms in the molecule: 0.1–40 parts by mass. (D) Curing catalyst: 0.001–20 parts by weight, and (E) Silane coupling agent: 0.05 to 20 parts by weight.

7. An addition-reaction curing liquid silicone adhesive with easy disintegration properties, comprising the following components (A) and (F) to (I) for the disintegration method of the joint member according to any one of claims 1 to 5, and wherein the content of the material employing electromagnetic induction heating is 3% by mass or less. (A) Hydroxide compounds with a decomposition temperature of 180–600°C: their amount constitutes 25–80% by mass of the total adhesive. (F) Alkenyl-containing organopolysiloxanes with alkenyl groups bonded to silicon atoms at the ends of the molecular chains: 100 parts by mass. (G) An organohydrogen polysiloxane having at least two hydrogen atoms bonded to silicon atoms in its molecule: in an amount such that, relative to 1 mole of alkenyl groups bonded to silicon atoms in component (F), the number of hydrogen atoms bonded to silicon atoms is 0.01 to 3 moles. (H) Platinum group metal catalysts: 0.01–1000 ppm relative to the combined stoichiometry of components (F) and (G), converted to mass of platinum group metal atoms. (I) Adhesive agent: 0.05 to 20 parts by weight.

8. A UV-curable liquid silicone adhesive with easy disintegration properties, comprising the following components (A), (J), and (K) for the disintegration method of the bonded member according to any one of claims 1 to 5, wherein the content of the material used for electromagnetic induction heating is 3% by mass or less. (A) Hydroxide compounds with a decomposition temperature of 180–600°C: their amount constitutes 25–80% by mass of the total adhesive. (J) UV-reactive organopolysiloxanes: 100 parts by weight, and (K) Photopolymerization initiator: 0.01 to 10 parts by weight.

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