Addition-curable silicone composition, cured silicone product, bonded member, and method for dispensing bonded member

Abstract

(A) 100 parts by mass of an organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in the molecule, (B) 0.1-10 parts by mass of a linear organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in the molecule, (C) 0.1-10 parts by mass of an organosilicon compound having an arylene skeleton and a hydrogen atom bonded to silicon atoms, and (D) and (E) 1-100 parts by mass of particles capable of generating heat by microwave irradiation. The addition-curable silicone composition can form a cured product which does not undergo reduction in adhesiveness or adhesion to a member even when exposed to a high-temperature environment of about 150 DEG C, and which can be easily peeled off from the member in a short period of time and with low energy consumption.

Description

Technical Field

[0001] The present invention relates to an addition-curable silicone composition, a cured silicone product, a joined member, and a method for disassembling the joined member. Background Art

[0002] Research is underway to reduce the environmental burden and costs associated with the recovery, repair, and recycling of automotive components, electrical and electronic products, and other automotive components. However, joint components must maintain a balance between adhesive strength and ease of disassembly, allowing for peeling as needed.

[0003] Methods for disassembling joined members include, for example, methods using adhesives containing microcapsules or foaming agents that expand upon heating (Patent Document 1) and disassembly adhesives imparted with thermal meltability or thermal decomposition properties (Patent Documents 2 and 3).

[0004] Silicone-based adhesives and sealing materials are widely used in the automotive, electrical and electronic, and construction fields, etc., due to their excellent properties such as heat resistance and weather resistance.

[0005] However, silicone adhesives are difficult to disassemble, recycling, and repair because they firmly bond components to the silicone adhesive using heat. Therefore, even in applications where silicone adhesives are used for bonding, recyclable bonded components and methods for disassembling them are needed.

[0006] For example, Patent Document 4 reports a curable liquid silicone adhesive blended with aluminum hydroxide, which decomposes at temperatures around 160°C, at a specific ratio. Adhesive components joined using this adhesive exhibit sealing properties even after exposure to temperatures of room temperature or around 150°C. However, exposure to temperatures above 160°C reduces the sealing properties, allowing the components to be easily separated.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 2002-187973

[0010] Patent Document 2: Japanese Patent Application Laid-Open No. 2004-231808

[0011] Patent Document 3: Japanese Patent Application Laid-Open No. 2015-196793

[0012] Patent Document 4: Japanese Patent Application Laid-Open No. 2022-183437 Summary of the Invention

[0013] Problems to be solved by the invention

[0014] However, the thermally disintegrating adhesive of Patent Document 4 cannot be used for joining parts used in high-temperature environments because its adhesiveness decreases at high temperatures. In addition, the use of a heating furnace requires several hours of heating, which results in high energy consumption.

[0015] The present invention has been completed in view of the above-mentioned actual situation, and its purpose is to provide an addition-curing silicone composition that can form a cured product that does not suffer from a decrease in adhesion or adhesion to components even when exposed to a high-temperature environment of approximately 150°C, and can be easily peeled off from the components in a short time and with little energy consumption; a joined component in which multiple components are joined using the cured product of the composition; and a method for disassembling the joined component.

[0016] Means for solving problems

[0017] The present inventors have conducted intensive research to achieve the above-mentioned objectives and have discovered that an addition-curing silicone composition comprising a specific organosilicon compound and microwave-heatable particles blended at specific contents can form a cured product that does not exhibit a decrease in adhesion or adhesion to components even when exposed to high-temperature environments near 150°C, and can be easily removed from components in a short time and with minimal energy consumption. This has led to the completion of the present invention.

[0018] That is, the present invention provides:

[0019] 1. An addition-curable silicone composition comprising:

[0020] (A) Organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in the molecule: 100 parts by mass

[0021] (B) 0.1 to 10 parts by mass of a linear organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in its molecule

[0022] (C) An organosilicon compound having an arylene skeleton and hydrogen atoms bonded to silicon atoms: 0.1 to 10 parts by mass

[0023] (D) a hydrosilylation reaction catalyst and

[0024] (E) particles capable of generating heat by microwave irradiation: 1 to 100 parts by mass;

[0025] 2. The addition-curable silicone composition according to 1, wherein the component (C) is an organosilicon compound represented by the following general formula (1):

[0026] [Chemistry 1]

[0027]

[0028] (Where R 1 Each independently represents an alkyl group having 1 to 6 carbon atoms, X represents a divalent organic group which may contain an ether bond and has one or more phenylene skeletons, and k is each independently an integer of 3 to 5.

[0029] 3. The addition-curable silicone composition according to 2, wherein X is a group represented by the following formula (2), the following formula (3), or the following formula (4),

[0030] [Chemistry 2]

[0031]

[0032] (In each formula, the dotted line represents the end connected to the silicon atom.)

[0033] 4. The addition-curable silicone composition according to item 1, wherein the particles (E) capable of generating heat by microwave irradiation are particles comprising at least one selected from the group consisting of carbon, iron oxide, titanium oxide, and silicon carbide;

[0034] 5. A cured silicone product obtained by curing the addition-curable silicone composition according to any one of 1 to 4;

[0035] 6. A joined member in which a plurality of members are joined using the cured product according to 5;

[0036] 7. The joining member according to 6, wherein at least one of the plurality of members is a polyphenylene sulfide resin;

[0037] 8. A method for disassembling a joined member, comprising a disassembly step of irradiating at least the solidified material in the joined member according to 6 with microwaves to separate the plurality of members and disassemble the joined member;

[0038] 9. The method for disassembling a joined member according to 7, wherein the disassembling step includes a peeling step of peeling the cured product of the addition-curable silicone composition from the plurality of members using a peeling means.

[0039] Effects of the Invention

[0040] The addition-curable silicone composition of the present invention can form a cured product that does not suffer from decreased adhesion or adhesion to components even when exposed to high temperatures near 150°C, nor does it suffer from decreased adhesion and / or sealing properties upon microwave irradiation. Jointed components using this cured product, such as those joining multiple (particularly two) components made of organic resins and / or metals, can be disassembled in a short time using microwave irradiation with minimal energy consumption, allowing for easy recycling.

[0041] The cured product of the addition-curable silicone composition of the present invention having such characteristics can be suitably used as an adhesive or a sealing material for joints requiring heat resistance and requiring recycling. DETAILED DESCRIPTION

[0042] The present invention will be described in detail below.

[0043] [Addition-curing silicone composition]

[0044] The addition-curable silicone composition of the present invention contains the following components (A) to (E).

[0045] (A) an organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in the molecule

[0046] (B) a linear organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in the molecule

[0047] (C) an organosilicon compound having an arylene skeleton and hydrogen atoms bonded to silicon atoms

[0048] (D) Hydrosilylation Reaction Catalyst

[0049] (E) Particles that generate heat through microwave irradiation

[0050] [1](A)Ingredients

[0051] The component (A) is an organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in the molecule.

[0052] The alkenyl group is not particularly limited, but is preferably an alkenyl group having 2 to 8 carbon atoms. Specific examples thereof include vinyl, allyl, butenyl, pentenyl, hexenyl, and heptenyl groups. Among these, vinyl is preferred.

[0053] The bonding position of the alkenyl group in the component (A) is not particularly limited and may be at the molecular chain terminal or the molecular chain side chain. However, it is preferred that the alkenyl group be at the molecular chain terminal.

[0054] The organic group other than the alkenyl group bonded to a silicon atom of component (A) is not particularly limited, but examples thereof include substituted or unsubstituted monovalent hydrocarbon groups preferably having 1 to 18 carbon atoms, more preferably 1 to 12 carbon atoms, further preferably 1 to 10 carbon atoms, and still further preferably 1 to 7 carbon atoms.

[0055] Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl and phenethyl; and halogenated alkyl groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl. Among these, methyl and phenyl are particularly preferred.

[0056] Examples of the molecular structure of the component (A) include a linear structure, a partially branched linear structure, a cyclic structure, and a three-dimensional network structure.

[0057] From the perspective of the physical properties of the resulting cured product and the handleability of the composition, the viscosity of component (A) at 25° C. is preferably 100 to 500,000 mPa·s, more preferably 300 to 100,000 mPa·s. The viscosity can be measured using a B-type rotational viscometer.

[0058] Specific examples of the component (A) include dimethylsiloxane-methylvinylsiloxane copolymers having trimethylsiloxy groups terminated at both ends of the molecular chain, methylvinylpolysiloxane having trimethylsiloxy groups terminated at both ends of the molecular chain, dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymers having trimethylsiloxy groups terminated at both ends of the molecular chain, dimethylpolysiloxane having dimethylvinylsiloxy groups terminated at both ends of the molecular chain, methylvinylpolysiloxane having dimethylvinylsiloxy groups terminated at both ends of the molecular chain, dimethylsiloxane-methylvinylsiloxane copolymers having dimethylvinylsiloxy groups terminated at both ends of the molecular chain, dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymers having trimethylsiloxy groups terminated at both ends of the molecular chain, and dimethylpolysiloxane having trimethylsiloxy groups terminated at both ends of the molecular chain. 3 3SiO 0.5 The siloxane units and R 3 2R 4 SiO 0.5 The siloxane units and R 3 An organopolysiloxane copolymer composed of a unit represented by 2SiO and a siloxane unit represented by SiO2, 3 3SiO 0.5 The siloxane units and R 3 2R 4 SiO 0.5 An organopolysiloxane copolymer composed of a siloxane unit represented by R and a siloxane unit represented by SiO2, 3 2R 4 SiO 0.5 The siloxane units and R 3 An organopolysiloxane copolymer composed of a siloxane unit represented by 2SiO and a siloxane unit represented by SiO2, 3 R 4 Siloxane units represented by SiO and R 3 SiO 1.5 The siloxane unit or R 4 SiO 1.5The organopolysiloxane copolymers composed of the siloxane units shown above, and mixtures composed of two or more of these. 3 is a monovalent hydrocarbon group other than an alkenyl group, and is an organic group other than the alkenyl group bonded to a silicon atom, and is particularly preferably a methyl group or a phenyl group. 4 It is an alkenyl group, and is the alkenyl group as described above, and is preferably a vinyl group. Component (A) may be used alone or in combination of two or more.

[0059] [2] (B) Component

[0060] Component (B) is a linear organohydrogenpolysiloxane having at least two, and preferably three or more, silicon-bonded hydrogen atoms (i.e., SiH groups) per molecule. The position of the SiH groups in component (B) is not particularly limited and may be at the molecular chain terminals or side chains.

[0061] Examples of the organic group other than the SiH group in the component (B) include the same groups as exemplified as the organic group other than the alkenyl group bonded to a silicon atom in the component (A) above. The organic group is preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms, more preferably 1 to 7 carbon atoms, and further preferably a substituted or unsubstituted alkyl group or phenyl group having 1 to 3 carbon atoms.

[0062] Specific examples of the substituted or unsubstituted alkyl group having 1 to 3 carbon atoms include a methyl group and a 3,3,3-trifluoropropyl group.

[0063] Specific examples of component (B) include 1,1,3,3-tetramethyldisiloxane; 1,3,5,7-tetramethyltetracyclosiloxane; 1,3,5,7,8-pentamethylpentacyclosiloxane; cyclic methylhydrogenpolysiloxanes such as trimethylsiloxy end-capping; Methylhydrogen polysiloxane, dimethylsiloxane-methylhydrogen siloxane copolymer with trimethylsiloxy groups terminated at both ends of the molecular chain, methylhydrogen polysiloxane with silanol groups terminated at both ends of the molecular chain, dimethylsiloxane-methylhydrogen siloxane copolymer with silanol groups terminated at both ends of the molecular chain, dimethylhydrogen siloxy groups terminated at both ends of the molecular chain, methylhydrogen polysiloxane with dimethylhydrogen siloxy groups terminated at both ends of the molecular chain, dimethylhydrogen siloxy groups terminated at both ends of the molecular chain, and dimethylhydrogen siloxane-methylhydrogen siloxane copolymer with dimethylhydrogen siloxy groups terminated at both ends of the molecular chain. Component (B) may be used alone or in combination of two or more.

[0064] The weight average molecular weight of the component (B) is preferably 100 to 10000, more preferably 200 to 5000. The weight average molecular weight can be measured as a standard polystyrene equivalent value using gel permeation chromatography (GPC).

[0065] The amount of component (B) added is 0.1 to 10 parts by mass, preferably 0.5 to 8 parts by mass, relative to 100 parts by mass of component (A). The amount of component (B) added is such that the ratio of hydrogen atoms bonded to silicon atoms (i.e., SiH groups) in component (B) to the number of alkenyl groups in component (A) is 0.1 to 5.0, preferably 0.5 to 4. If the amount is less than 0.1 parts by mass, curability may be insufficient, while if it exceeds 10 parts by mass, the cured product may become brittle.

[0066] [3] (C) Component

[0067] The component (C) is an organosilicon compound having an arylene skeleton and at least one, preferably 1 to 20, more preferably 2 to 10 hydrogen atoms (SiH groups) bonded to silicon atoms, and functions as an adhesion-imparting component.

[0068] Examples of the arylene skeleton include divalent aromatic groups such as phenylene, naphthylene, and anthracene, and phenylene is preferred.

[0069] Examples of organic groups other than SiH groups include substituted or unsubstituted monovalent organic groups preferably having 1 to 18 carbon atoms, more preferably 1 to 12 carbon atoms, and even more preferably 1 to 6 carbon atoms. Specific examples include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl and phenethyl; haloalkyl groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl; alkenyl groups such as vinyl, allyl, butenyl, pentenyl, hexenyl, and heptenyl; epoxy groups such as glycidyloxy; alkoxysilyl groups such as trimethoxysilyl, triethoxysilyl, and methyldimethoxysilyl; and functional groups such as ester groups, acryloyl groups, methacryloyl groups, carboxylic anhydride groups, isocyanate groups, amino groups, and amido groups. Among these, methyl groups are preferred.

[0070] As the organosilicon compound of the component (C), a compound represented by the following general formula (1) is preferred.

[0071] [Chemistry 3]

[0072]

[0073] In formula (1), R 1Each independently represents an alkyl group having 1 to 6 carbon atoms, X represents a divalent organic group which may contain an ether bond and has one or two or more phenylene skeletons, and k is each independently an integer of 3 to 5.

[0074] As R 1 The alkyl group having 1 to 6 carbon atoms includes methyl, ethyl, propyl, butyl, pentyl, hexyl and the like, and preferably methyl.

[0075] As the divalent organic group represented by X, a group represented by the following formula (2), the following formula (3), the following formula (4), or the following formula (5) is preferred, and a group represented by the following formula (2), the following formula (3), or the following formula (4) is more preferred.

[0076] [Chemistry 4]

[0077]

[0078] (Where the dotted line represents the bond with the silicon atom.)

[0079] Specific examples of the component (C) include compounds represented by the following structural formulas. The component (C) may be used alone or in combination of two or more.

[0080] [Chemistry 5]

[0081]

[0082] (wherein n is independently an integer of 1 to 3.)

[0083] [Chemistry 6]

[0084]

[0085] (wherein n is independently an integer of 1 to 3.)

[0086] The amount of component (C) is 0.1 to 10 parts by mass, preferably 0.1 to 9 parts by mass, and more preferably 0.2 to 8 parts by mass, relative to 100 parts by mass of component (A). If the amount is less than 0.1 parts by mass, sufficient adhesion may not be achieved, while if it exceeds 10 parts by mass, physical properties may be degraded.

[0087] Furthermore, the molar ratio of the total SiH groups in the composition to the total silicon atom-bonded alkenyl groups in the composition (particularly, the molar ratio of the SiH groups in the components (B) and (C) to the total alkenyl groups in the components (A) and (C)) is preferably in the range of 1.0 to 5.0, more preferably in the range of 1.2 to 4.0, and even more preferably in the range of 1.5 to 3.0.

[0088] [4] (D) Component

[0089] The component (D) is a hydrosilylation reaction catalyst, and is a catalyst for promoting the hydrosilylation reaction between the alkenyl groups of the component (A) and the SiH groups of the components (B) and (C).

[0090] As the catalyst for the hydrosilylation reaction, platinum (including platinum black), rhodium, palladium and other platinum group metal elements can be listed; platinum chloride, chloroplatinic acid and chlorine such as H2PtCl4·nH2O, H2PtCl6·nH2O, NaHPtCl6·nH2O, KHPtCl6·nH2O, Na2PtCl6·nH2O, K2PtCl4·nH2O, PtCl4·nH2O, PtCl2, Na2HPtCl4·nH2O (wherein, n is an integer from 0 to 6, preferably 0 or 6.) Platinum salts; alcohol-modified chloroplatinic acid (see U.S. Patent No. 3,220,972); complexes of chloroplatinic acid and olefins (see U.S. Patent Nos. 3,159,601, 3,159,662, and 3,775,452); catalysts in which a platinum group metal such as platinum black or palladium is supported on a carrier such as alumina, silica, or carbon; rhodium-olefin complexes; chlorotris(triphenylphosphine)rhodium (Wilkinson catalyst); platinum group metal catalysts such as complexes of platinum chloride, chloroplatinic acid, or chloroplatinic salts with vinyl-containing siloxanes. Component (D) may be used alone or in combination of two or more.

[0091] The amount of component (D) used may be a catalytic amount, and is preferably 0.1 to 500 ppm, more preferably 0.5 to 200 ppm, calculated as the mass of the platinum group metal relative to component (A).

[0092] [5] (E) ingredient

[0093] Component (E) is a particle that can generate heat using microwaves. Any particle with these properties can be used, but particles with a high dielectric constant are particularly preferred because they have a high microwave absorptivity, allowing for efficient heat generation in a short time. The dielectric constant is preferably 3 to 1000 at 3 GHz, and more preferably 5 to 800.

[0094] Microwave-heatable particles are inorganic substances, including carbons such as acetylene black, furnace black, channel black, thermal black, and Ketjen black; iron oxides such as ferrous (II) oxide, iron (III) oxide, and ferroferric oxide; titanium oxide compounds such as titanium oxide (TiO), titanium dioxide (TiO2), and titanium trioxide (Ti2O3); ferrites such as spinel ferrite, magnetite ferrite, and garnet ferrite; and silicon carbide. Of these, preferably, one or more selected from carbon, iron oxide, titanium oxide, and silicon carbide are included, with acetylene black, titanium dioxide, and silicon carbide being more preferred. Component (E) may be used alone or in combination of two or more.

[0095] The average particle size of the particles capable of generating heat using microwaves is preferably 0.05 to 100 μm, more preferably 0.1 to 80 μm. If the average particle size is smaller than 0.05 μm, the viscosity of the composition increases, preventing high-intensity filling and sometimes failing to achieve a sufficient heat generation effect. If the average particle size is larger than 100 μm, the rubber's flexibility may be impaired. The average particle size can be determined as the cumulative weight average value D50 (or median diameter) using a particle size distribution analyzer employing a laser diffraction method or the like.

[0096] The surface of the particles capable of generating heat by microwaves may be untreated or may be subjected to surface treatment (hydrophobic treatment).

[0097] Examples of the treatment agent for surface treatment include aluminum oxide, silicon dioxide, stearic acid, silane coupling agents, and organosilicon compounds. Surface treatment can be performed using known methods. The treatment amount is not particularly limited, but is preferably 10% by mass or less (usually 0.1 to 8% by mass), and more preferably 0.5 to 6% by mass.

[0098] The content of component (E) is 1 to 100 parts by mass, preferably 10 to 60 parts by mass, relative to 100 parts by mass of component (A). If it is less than 1 part by mass, sufficient heat generation cannot be achieved, while if it exceeds 100 parts by mass, the viscosity of the composition increases, and the discharge property during mixing and application deteriorates.

[0099] [6](F)Component

[0100] The addition-curable silicone composition of the present invention may contain an addition reaction control agent as component (F) as needed to prevent viscosity increase and gelation before heat curing during preparation or application to a substrate.

[0101] As the addition reaction control agent, an acetylene alcohol compound or a compound in which the alcoholic hydroxyl group of the compound is modified with silane or siloxane is preferred.

[0102] The acetylene alcohol compound may be any compound in which the acetylene group and the hydroxyl group are present in the same molecule, and particularly preferably a compound in which the acetylene group and the hydroxyl group are bonded to the same carbon atom. Specific examples thereof include compounds represented by the following structural formula.

[0103] [Chemistry 7]

[0104]

[0105] In addition, compounds in which the alcoholic hydroxyl group of an acetylene alcohol compound is modified with silane or siloxane refer to compounds in which the hydrogen atom of the hydroxyl group of the acetylene alcohol is bonded to the silane or siloxane portion in a form substituted by a Si—O—C bond. Specific examples thereof include compounds represented by the following structural formula.

[0106] [Chemistry 8]

[0107]

[0108] (In the formula, p is an integer of 0 to 50, and q is an integer of 1 to 50, preferably 3 to 50. The order of arrangement of the siloxane units in parentheses may be arbitrary.)

[0109] The amount of component (F) is preferably 0.0001 to 5 parts by mass, more preferably 0.001 to 3 parts by mass, and even more preferably 0.01 to 1 part by mass relative to 100 parts by mass of component (A). Component (F) may be used alone or in combination of two or more.

[0110] [7] (G) ingredient

[0111] In the addition-curable silicone composition of the present invention, reinforcing silica may be blended to enhance mechanical strength. Examples of reinforcing silica include fumed silica, precipitated silica, calcined silica, quartz powder, and diatomaceous earth. Furthermore, a specific surface area of ​​50 m2 by the BET method is preferred. 2 / g or more, especially 50 to 500m 2 / g of fine powdered silica. Such fine powdered silica can be used directly, but in order to impart fluidity to the composition, it is preferably treated with an organosilicon compound such as methylchlorosilanes, dimethylpolysiloxane, or hexamethyldisilazane.

[0112] The amount of component (G) used is preferably 0.1 to 200 parts by mass, more preferably 1 to 100 parts by mass, relative to 100 parts by mass of component (A). Component (G) may be used alone or in combination of two or more.

[0113] [8] Other ingredients

[0114] The addition-curable silicone composition of the present invention may further contain, in addition to the above-mentioned components, an adhesion-imparting agent other than the component (C), a reinforcing silicone resin, and the like, within a range not impairing the object of the present invention.

[0115] Examples of the adhesion-imparting agent other than the component (C) include γ-acryloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-mercapto Silane coupling agents such as propyltrimethoxysilane, γ-glycidoxypropyltriisopropenoxysilane, and γ-glycidoxypropylmethyldiisopropenoxysilane; allyl glycidyl ether, vinylcyclohexene monoxide, diethyl 2-allylmalonate, allyl benzoate, diallyl phthalate, tetraallyl pyromellitate (trade name: TRIAM805, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.); and triallyl isocyanurate.

[0116] When a tackifier other than component (C) is added, the amount thereof is preferably 0.05 parts by mass or more relative to 100 parts by mass of component (A), and preferably 0.5 to 10 parts by mass in consideration of rubber elasticity and adhesion.

[0117] The addition-curable silicone composition of the present invention can be produced by uniformly mixing the aforementioned components. The mixing method can be conventionally known, and examples of mixing apparatus include planetary mixers. Furthermore, all components can be mixed simultaneously, or one or more components can be mixed in several stages. Furthermore, a two-component system can be prepared that is mixed and used simultaneously.

[0118] [Cured silicone]

[0119] A cured silicone material can be obtained by curing the addition-curable silicone composition of the present invention.

[0120] The curing method and conditions are the same as those for known curable silicone rubber compositions. For example, while sufficient curing is possible even at room temperature, heating is also possible as needed. When heated, curing is preferably carried out at a temperature of 60 to 200°C, particularly 80 to 170°C. Curing time varies depending on the curing temperature, molding method, and other factors, but is generally about 1 minute to 24 hours.

[0121] [Joint member]

[0122] The joining member of the present invention is a member formed by joining a plurality (particularly two) of the same or different types of members using the above-mentioned cured silicone material (adhesive member composed of a cured silicone rubber material).

[0123] In the joined member of the present invention, the joined members are preferably selected from organic resin members and metal members, and more preferably, at least one (one) of the multiple joined members is an organic resin member. Examples of such combinations of members include combinations of the same or different organic resin members, and combinations of metal members and organic resin members.

[0124] Examples of organic resins constituting organic resin components include PBT (polybutylene terephthalate resin), PPS (polyphenylene sulfide resin), polyamide resins such as PA66 (nylon 66) and PA6 (nylon 6), and PC (polycarbonate resin). Examples of metals constituting metal components include aluminum, iron, SUS, and copper. Among these, PPS resin is particularly preferred due to its extremely high strength and rigidity, and excellent wear resistance, chemical resistance, and heat resistance.

[0125] In the method for producing a joined component of the present invention, the aforementioned addition-curable silicone composition is applied to the surface of one organic resin or metal component in the shape of a joining portion (e.g., a gasket) by hand or mechanical dispensing, then the other component is bonded and cured using the aforementioned curing method. The components can then be secured with bolts or the like, as needed.

[0126] Examples of the joining member include automobile parts such as engines, transmissions, ECUs, and PCUs, and electric and electronic parts such as smartphones, tablets, liquid crystal displays, and battery packs, with automobile parts and electric and electronic parts being preferred.

[0127] The bonded components are preferably easily disassembled, with a certain degree of adhesion during normal use, but the adhesion strength decreases to a level that allows separation of the components after microwave irradiation. Specifically, the initial shear adhesion strength of the bonded components is preferably 1.5 MPa or greater, more preferably 2.0 MPa or greater, and the shear adhesion strength after microwave irradiation is preferably 1.0 MPa or less. This shear adhesion strength is measured according to the method specified in JIS K 6850:1999. Furthermore, the initial and post-microwave shear adhesion strengths can be achieved by ensuring that the composition of the addition-curable silicone composition falls within the aforementioned specific ranges.

[0128] [Disassembly method]

[0129] The method for disassembling the joined components of the present invention includes, for example, a method in which a cured product (adhesive silicone rubber cured product) formed by curing an addition-curable silicone composition serving as the bonding member of the joined components is irradiated with microwaves and then allowed to separate naturally from the components while heated, or a method in which the components are separated by applying force manually or using an appropriate peeling means such as a spatula to the microwave-irradiated components. Furthermore, the disassembled components can be recycled.

[0130] The microwave irradiation preferably has a frequency, output, and irradiation time such that the adhesive force is reduced to the extent that the components can be separated after irradiation. For example, the frequency is 300 MHz to 300 GHz, and the output can be selected within the range of 300 W to 5000 W. The irradiation time is not particularly limited, but is preferably 30 minutes or less, and more preferably 15 minutes or less.

[0131] Example

[0132] The present invention is described in detail below with reference to Examples and Comparative Examples. However, the present invention is not limited to the following Examples. In the following examples, Vi represents a vinyl group, Me represents a methyl group, the kinematic viscosity is the value measured at 25°C using an Ostwald viscometer, and the weight-average molecular weight is the value based on standard polystyrene measured by GPC.

[0133] [1] Preparation of addition-curing silicone compositions

[0134] [Examples 1-1 to 1-7, Comparative Examples 1-1 to 1-4]

[0135] The following components were mixed in the amounts (parts by mass) shown in Tables 1 and 2 to prepare addition-curable silicone compositions.

[0136] (A)Ingredients

[0137] (A-1): dimethyl polysiloxane terminated with dimethylvinylsilyl groups at both ends (kinematic viscosity at 25°C: 100,000 mm 2 / s, vinyl content 0.0025 mol / 100 g)

[0138] (A-2): Made of Me3SiO 1 / 2 unit, Me2ViSiO 1 / 2 unit and SiO 4 / 2 Unit structure, polysiloxane (Me3SiO 1 / 2 Unit: Me2ViSiO 1 / 2 Unit: SiO 4 / 2 Unit molar ratio 7:1:10, weight average molecular weight 4000, vinyl content 0.08 mol / 100g)

[0139] (B) Ingredients

[0140] (B-1) Organohydrogenpolysiloxane represented by the following formula

[0141] [Chemistry 9]

[0142]

[0143] (C) Ingredients

[0144] (C-1) an organosilicon compound represented by the following structural formula

[0145] [Chemistry 10]

[0146]

[0147] (C-2) an organosilicon compound represented by the following structural formula

[0148] [Chemistry 11]

[0149]

[0150] (C-3) an organosilicon compound represented by the following structural formula

[0151] [Chemistry 12]

[0152]

[0153] (C'-4) Cyclic organohydrogen polysiloxane represented by the following structural formula

[0154] [Chemistry 13]

[0155]

[0156] (C'-5) Cyclic organohydrogen polysiloxane represented by the following structural formula

[0157] [Chemistry 14]

[0158]

[0159] (D) Component (D-1) Toluene solution of platinum-divinyltetramethyldisiloxane complex (platinum concentration: 0.5% by mass)

[0160] (E) Ingredients

[0161] (E-1) Green silicon carbide powder (Shinano-Rundum GP, manufactured by Shinano Electric Refining Co., Ltd., particle size #400)

[0162] (E-2) Green silicon carbide powder (Shinano-Rundum GP, manufactured by Shinano Electric Refining Co., Ltd., particle size #4000)

[0163] (F)Ingredients

[0164] (F-1)Ethynylcyclohexanol (addition reaction control agent)

[0165] [Table 1]

[0166]

[0167] [Table 2]

[0168]

[0169] [2] Production of cured products and joint components

[0170] [Examples 2-1 to 2-9, Comparative Examples 2-1 to 2-7]

[0171] Two flat plates with a width of 25 mm, a length of 100 mm and a thickness of 2 mm were overlapped by 10 mm in the longitudinal direction. The addition-curing silicone compositions obtained in the above-mentioned Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-7 were filled in between so as to have a bonding area of ​​25 mm × 10 mm and a thickness of 2 mm. The compositions were cured by heating at 150°C for 60 minutes to produce a joining component.

[0172] In addition, as the material of the flat plate, the following combination of materials was used.

[0173] Joint member 1: PPS resin (manufactured by Tosoh Corporation (Susteel GS-40, glass fiber 40% by mass)

[0174] Joint member 2: PPS resin (manufactured by Tosoh Corporation (Susteel GS-40, glass fiber 40% by mass) and die-cast aluminum (ADC12, JIS H 5302: 2006)

[0175] Joint member 3: Joint between PPS resin (Torelina A503-F1 manufactured by Toray Industries, Ltd.)

[0176] Joining member 4: Joining of PPS resin (Torelina A503-F1 manufactured by Toray Industries, Ltd.) and die-cast aluminum (ADC12, JIS H5302:2006)

[0177] The adhesive strength (disassembly property) of each bonded member produced as described above was evaluated by the following evaluation method. The results are shown in Tables 3 and 4.

[0178] (1) Adhesion (initial)

[0179] The shear adhesive strength of the prepared joined member was measured according to the method specified in JIS K 6850:1999. A shear adhesive strength of 2.0 MPa or more was evaluated as "0", and a shear adhesive strength of less than 2.0 MPa was evaluated as "x".

[0180] (2) Disintegration (after high temperature exposure and microwave irradiation)

[0181] The prepared bonded components were placed in a 150°C oven for 100 and 500 hours. After cooling to room temperature, the test pieces were irradiated with microwaves for 6 minutes using a Shikoku Instrumentation Industry Co., Ltd. μReactor EX at a frequency of 2.4 GHz and an output of 1000 W. Immediately after irradiation, the bonded components were removed, one of the adherends (two flat sheets) was secured, and the other adherend was manually peeled perpendicularly to the bonded surface to observe whether it exhibited interfacial delamination or cohesive failure.

[0182] [Table 3]

[0183]

[0184] [Table 4]

[0185]

[0186] As shown in Tables 3 and 4, it can be seen that even after exposure to a high temperature of 150°C for 500 hours, the bonded components bonded using the cured products of the addition-curable silicone compositions prepared in each example can be easily debonded from the adherend surface by microwave irradiation in a short time with minimal energy consumption, without any residual adhesive remaining on the adherend surface.

[0187] On the other hand, when the composition of Comparative Example 1-1 containing no microwave-generated particles and the compositions of Comparative Examples 1-2 to 1-4 containing microwave-generated particles in a predetermined amount or less were used, disintegrability was not achieved.

[0188] In addition, in the case of the compositions of Comparative Examples 1-6 and 1-7 in which the content of the particles capable of generating heat by microwaves was a predetermined amount but the component (C) was changed to a SiH group-containing compound having no arylene skeleton, it was found that after exposure to a high temperature of 150°C for 100 hours,

[0189] Even when microwave irradiation is performed, the interface cannot be easily peeled off and becomes cohesive failure.

[0190] There is residual adhesive on the surface of the attachment.

Claims

1. An addition-curable silicone composition comprising: (A) an organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in the molecule: 100 parts by mass, (B) 0.1 to 10 parts by mass of a linear organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in its molecule, (C) an organosilicon compound having an arylene skeleton and hydrogen atoms bonded to silicon atoms: 0.1 to 10 parts by mass, (D) a hydrosilylation reaction catalyst, and (E) Particles capable of generating heat by microwave irradiation: 1 to 100 parts by mass.

2. The addition-curable silicone composition according to claim 1, wherein The component (C) is an organosilicon compound represented by the following general formula (1): [Chemistry 1] Where R 1 Each independently represents an alkyl group having 1 to 6 carbon atoms, X represents a divalent organic group which may contain an ether bond and has one or two or more phenylene skeletons, and k is each independently an integer of 3 to 5.

3. The addition-curable silicone composition according to claim 2, wherein The X is a group represented by the following formula (2), the following formula (3), or the following formula (4), [Chemistry 2] In each formula, the dotted line represents the end bonded to the silicon atom.

4. The addition-curable silicone composition according to claim 1, wherein The (E) particles capable of generating heat by microwave irradiation are particles containing one or more selected from the group consisting of carbon, iron oxide, titanium oxide, and silicon carbide. 5 . A cured silicone product obtained by curing the addition-curable silicone composition according to claim 1 .

6. A joined member in which a plurality of members are joined using the cured product according to claim 5.

7. The joining member according to claim 6, wherein At least one of the plurality of members is a polyphenylene sulfide resin.

8. A method for disassembling a joined member, comprising a disassembling step, wherein: At least the cured product in the joined member according to claim 6 is irradiated with microwaves to separate the plurality of members and disassemble the joined member.

9. The method for disassembling a joined member according to claim 7, wherein: The disassembling step includes a peeling step of peeling the cured product of the addition-curable silicone composition from the plurality of members using a peeling means.

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