Organic silicon resin dissolving agent and method for separating organic silicon coating from base cloth

Abstract

The invention provides an organic silicon resin dissolving agent. The organic silicon resin dissolving agent comprises the following components in percentage by mass: (A) 1-90% of silicate compound shown in the following general formula (1) and / or (2); and (B) 99-10% by mass of an aprotic organic solvent having a relative dielectric constant of 10.0 or less. As a result, it is possible to provide a silicone resin dissolving agent for recovering a base material by dissolving a silicone resin from a molded product in which a resin base material or a metal base material is integrated with a silicone resin such as silicone rubber. In the formula # imgabs 0 # imgabs 1 #, R is independently a group selected from an alkyl group having 1-10 carbon atoms optionally substituted by halogen atoms and an aryl group having 6-10 carbon atoms, M is a cation selected from an alkali metal ion, a tetraalkylammonium ion, a benzyltrialkylammonium ion and a tetraalkylphosphonium ion, and n is an integer of 0-200.

Description

Technical Field

[0001] The invention relates to a silicone resin dissolving agent and a method for separating a silicone coating and a base fabric. Background Art

[0002] Silicone rubber is widely used in a variety of fields, such as connector seals and spark plug boots and other automotive parts, electrical and electronic parts such as rollers for copy machines and gaskets for microwave ovens, sealants and other construction parts, and other baby bottle nipples and diving equipment, due to its advantages such as heat resistance, cold resistance, safety, electrical insulation, and weather resistance. Among the above-mentioned various uses, there are also many examples of using it in combination with resin substrates or metal substrates.

[0003] In the past, a variety of methods have been proposed to obtain a molded product, which is formed by integrating a cured product of an addition-curing silicone rubber composition with a resin substrate or a metal substrate. For example, there is a method of applying a primer to the surface of a substrate, and applying an uncured silicone rubber composition from above and then curing it to bond. In addition, there is also a method of applying an adhesive to the interface of the substrate for integration. Furthermore, there is a method of curing a self-adhesive silicone rubber material from above the substrate, and the self-adhesive silicone rubber material is formed by mixing an internally added adhesive into the silicone rubber. In the above examples, the silicone rubber and the substrate are mostly firmly bonded together.

[0004] In addition, the silicone coated base fabric obtained by coating the surface of PET (polyethylene terephthalate) base fabric or PA66 (nylon 66) base fabric with curable silicone rubber has excellent flame retardancy, air tightness, etc. Therefore, it is suitable for applications such as automotive airbag base fabric and tent curtain coating. In the above applications, it is sought that the silicone rubber coating material and the base fabric are firmly bonded together. As means thereof, primer coating on the base fabric, internal addition adhesive to the silicone rubber, etc. can be listed.

[0005] On the other hand, in recent years, in order to reduce CO2 emissions and reduce waste, the recycling of plastics and metals has been booming. However, in the above-mentioned molded products integrated with silicone rubber, the silicone rubber and the substrate are firmly bonded together, so it is difficult to separate the two and the recycling of the substrate is difficult. Therefore, as a method for separating silicone rubber from the substrate, a method of dissolving the silicone rubber can be considered.

[0006] As a method for dissolving silicone rubber, a silicone dissolving liquid containing chlorophosphonitrile and a linear polysiloxane with a degree of polymerization of 10 to 50 is disclosed (Patent Document 1). In this method, silicone rubber can be selectively dissolved without swelling other plastic components. However, the use of highly toxic chlorophosphonitrile may cause health damage and environmental burden to the surrounding environment.

[0007] As another method for dissolving silicone rubber, a resin dissolving solution containing alkylbenzene sulfonic acid and hydrochlorofluoroolefin is disclosed (Patent Document 2). In this method, hydrochlorofluoroolefin with low environmental burden is used as a solvent, and silicone resin, urethane resin, polyamide resin, etc. can be dissolved. However, since strongly acidic alkylbenzene sulfonic acid is used, it cannot be used to dissolve and separate silicone rubber from a metal substrate or an acid-resistant resin substrate.

[0008] In addition, as a method for separating silicone rubber from a resin base cloth, a method is disclosed in which a silicone-coated base cloth for an airbag after silicone coating of a PA66 base cloth is mixed in a strong alkaline solution to separate the silicone rubber, the strong alkaline solution containing a tertiary amine, an anionic surfactant, and sodium hydroxide (Patent Document 3). However, this method requires a long-term treatment with a strong alkaline aqueous solution having a pH of 13 or more, which may damage the dissolution equipment. In addition, this method cannot be used for a resin substrate that cannot tolerate a strong alkaline.

[0009] In addition, as another method, a method is disclosed in which a silicone-coated base fabric for an airbag obtained by coating a PA66 base fabric with silicone is mixed in a solution containing an alkylbenzene sulfonic acid and a saturated hydrocarbon having a flash point of 70° C. or higher, thereby separating the base fabric (Patent Document 4). However, this method requires handling of a strongly acidic solution, which may cause corrosion of equipment and damage to the health of operators. In addition, this method cannot be used for a resin substrate that cannot withstand strong acidity.

[0010] Prior art literature

[0011] Patent Literature

[0012] Patent Document 1: Japanese Patent Application No. 2014-524941

[0013] Patent Document 2: Japanese Patent Application Publication No. 2021-165382

[0014] Patent Document 3: Japanese Patent Application Publication No. 2017-124553

[0015] Patent Document 4: Japanese Patent Application Publication No. 2022-073181 Summary of the invention

[0016] 1. Technical issues to be resolved

[0017] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a silicone resin dissolving agent for dissolving the silicone resin from a molded product in which a resin substrate or a metal substrate and a silicone resin such as silicone rubber are integrated, thereby recovering the substrate.

[0018] (II) Technical solution

[0019] In order to solve the above technical problems, the present invention provides a silicone resin dissolving agent, which comprises:

[0020] 1 to 90% by mass of (A) a silicate compound represented by the following general formula (1) and / or (2),

[0021] [Chemical formula 1]

[0022]

[0023] [Chemical formula 2]

[0024]

[0025] In the formula, R is independently a group selected from an alkyl group having 1 to 10 carbon atoms and an aryl group having 6 to 10 carbon atoms which is optionally substituted with a halogen atom, M is a cationic species selected from an alkali metal ion, a tetraalkylammonium ion, a benzyltrialkylammonium ion and a tetraalkylphosphonium ion, and n is an integer of 0 to 200; and

[0026] 99 to 10% by mass of (B) an aprotic organic solvent having a relative dielectric constant of 10.0 or less.

[0027] Such a silicone resin dissolving agent can dissolve the silicone resin from a molded product in which a resin substrate or a metal substrate and a silicone resin such as silicone rubber are integrated, thereby recovering the substrate.

[0028] In this case, it is preferred that M is a cationic species selected from the group consisting of sodium ion, potassium ion, tetramethylammonium ion, tetrabutylammonium ion, and tetrabutylphosphonium ion.

[0029] Such a silicone resin dissolving agent can function as a better silicone resin dissolving agent.

[0030] Preferably, all of the R groups are methyl groups.

[0031] Such a silicone resin dissolving agent can function as a further favorable silicone resin dissolving agent.

[0032] A method for separating an organic silicon coating from a base fabric is characterized in that the organic silicon coated base fabric is immersed in the above-mentioned organic silicon resin solvent.

[0033] According to the method for separating a silicone coating layer from a base fabric of the present invention, the silicone coating layer can be removed from the base fabric simply and satisfactorily.

[0034] (III) Beneficial effects

[0035] According to the present invention, an integrally formed product of a silicone resin (such as silicone rubber) and a resin substrate or a metal substrate can be immersed in a silicone resin dissolving agent containing a silicate compound and an aprotic organic solvent having a relative dielectric constant of 10.0 or less, thereby dissolving the silicone resin and recovering the substrate. DETAILED DESCRIPTION

[0036] The inventors of the present application conducted various studies to achieve the above-mentioned purpose and found that by immersing an integrally molded product of a silicone resin and a resin substrate or a metal substrate in a solution containing a silicate compound and a non-protonic organic solvent with a relative dielectric constant of less than 10.0, the silicone resin can be dissolved and the substrate can be recovered, thereby completing the present invention.

[0037] That is, the present invention is a silicone resin dissolving agent, which comprises:

[0038] 1 to 90% by mass of (A) a silicate compound represented by the following general formula (1) and / or (2),

[0039] [Chemical formula 3]

[0040]

[0041] [Chemical formula 4]

[0042]

[0043] In the formula, R is independently a group selected from an alkyl group having 1 to 10 carbon atoms and an aryl group having 6 to 10 carbon atoms which is optionally substituted with a halogen atom, M is a cationic species selected from an alkali metal ion, a tetraalkylammonium ion, a benzyltrialkylammonium ion and a tetraalkylphosphonium ion, and n is an integer of 0 to 200; and

[0044] 99 to 10% by mass of (B) an aprotic organic solvent having a relative dielectric constant of 10.0 or less.

[0045] <Silicone resin solvent>

[0046] The silicone resin dissolving agent of the present invention comprises (A) a silicate compound represented by the above general formula (1) and / or (2) and (B) an aprotic organic solvent having a relative dielectric constant of 10.0 or less.

[0047] Hereinafter, each component of the silicone resin dissolving agent of the present invention will be described in detail.

[0048] [A ingredient]

[0049] The component (A) is a silicate compound represented by the following general formula (1) and / or (2), and functions as a catalyst for dissolving (depolymerizing) siloxane bonds (—O—Si—O—).

[0050] [Chemical formula 5]

[0051]

[0052] [Chemical formula 6]

[0053]

[0054] In the formula, R is independently a group selected from an alkyl group having 1 to 10 carbon atoms and an aryl group having 6 to 10 carbon atoms which is optionally substituted with a halogen atom, M is a cationic species selected from an alkali metal ion, a tetraalkylammonium ion, a benzyltrialkylammonium ion and a tetraalkylphosphonium ion, and n is an integer of 0 to 200.

[0055] R in the general formula (1) or (2) is independently a group selected from an alkyl group having 1 to 10 carbon atoms and an aryl group having 6 to 10 carbon atoms. Specific examples thereof include: alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclohexyl, 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. Methyl groups are particularly preferred, and all methyl groups are more preferred.

[0056] M in the above general formula (1) or (2) is a cation species selected from alkali metal ions, tetraalkylammonium ions and tetraalkylphosphonium ions. Specific examples include: alkali metal ions such as lithium ions, sodium ions, potassium ions and cesium ions; quaternary ammonium ions such as tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetraisopropylammonium, tetrabutylammonium, tetrahexylammonium, benzyltrimethylammonium, benzyltriethylammonium and hexadecyltrimethylammonium; quaternary phosphonium ions such as tetramethylphosphonium, tetraethylphosphonium, tetrapropylphosphonium, tetraisopropylphosphonium, tetrabutylphosphonium and tetrahexylphosphonium, etc., and particularly preferably sodium ions, potassium ions, tetramethylammonium ions, tetrabutylammonium ions and tetrabutylphosphonium ions.

[0057] In the general formula (1) or (2), n is 0 to 200, preferably 2 to 150, more preferably 3 to 100, and even more preferably 5 to 50. If the number average degree of polymerization n exceeds 200, the viscosity of the obtained solution becomes high, the dissolution workability may deteriorate, and the post-treatment washing step may become complicated.

[0058] The amount of the silicate compound of component (A) is 1% to 90% by mass, preferably 2% to 85% by mass, and more preferably 5% to 80% by mass, relative to the total amount of the aprotic organic solvent (B) described later. If the amount is less than 1% by mass, the silicone rubber may not be fully decomposed, and if it is more than 90% by mass, the viscosity of the solution may increase, and the workability may deteriorate.

[0059] <Preparation of silicate>

[0060] Various silicates of component (A) can be prepared by mixing the corresponding catalyst with dialkyl cyclic polysiloxanes such as octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6), or dialkyl polysiloxanes terminated by dimethylsilanol groups at both ends, dialkyl polysiloxanes terminated by trimethylsiloxy groups at both ends, etc., under appropriate reaction conditions, together with part or all of component (B) as required. For example, when M in formula (1) or (2) is an alkali metal, the catalyst is the corresponding alkali metal hydroxide, when M is tetraalkylammonium, the catalyst is tetraalkylammonium hydroxide, and when M is tetraalkylphosphonium, the catalyst is tetraalkylphosphine hydroxide. The above-mentioned catalysts are sometimes sold in the form of a solution of water, ethanol, tetrahydrofuran, etc. In this case, there is also a method of mixing the catalyst solution with siloxane, and preparing the silicate while discharging the solution to the outside of the system by heating or reducing pressure. The reaction conditions vary depending on the catalyst. For example, if the catalyst is potassium hydroxide, it is necessary to heat at 145°C under normal pressure for about 2 hours. If the catalyst is tetraalkylammonium, it is necessary to heat at 45°C under reduced pressure for about 12 hours. If the catalyst is tetraalkylphosphonium, it is necessary to heat at 45°C under reduced pressure for about 6 hours.

[0061] In addition, as other preparation methods of (A) component, there is also a method for reacting organic alkali metal species with cyclic compounds such as hexamethylcyclotrisiloxane (D3). Specifically, methyl lithium or butyl lithium can be added dropwise to a solution of D3 in tetrahydrofuran at low temperature to prepare. In addition, as other methods, there is also a method for preparing by condensation reaction by making the alkali metal or organic alkali metal of the monomer act on a compound containing a silanol group. Specifically, after reacting organic alkali metals such as metallic lithium or methyl lithium, butyl lithium with trimethylsilanol or polydimethylsiloxane formed by dimethylsilanol end-capping at both ends at low temperature, D3 is put into it, so that the degree of polymerization can be adjusted.

[0062] <Method for measuring number average degree of polymerization of silicate compound>

[0063] The number average degree of polymerization of (A) component can be measured by GPC, but (A) component is alkaline, if directly measured, then the GPC device may be damaged. Therefore, preferably, dilute hydrochloric acid etc. are used to neutralize and then GPC is measured. Specifically, after (A) component is neutralized by a small amount of excessive dilute hydrochloric acid, the water layer is separated, and then KYOWAAD 500 (KyowaChemical Industry Co., Ltd. manufactures) is used to adsorb and neutralize excessive hydrochloric acid. Then, after filtering by a membrane filter, a sample for GPC measurement is prepared. Then, GPC analysis can be performed, for example, under the following conditions using toluene as a developing solvent, and the number average degree of polymerization is calculated by polystyrene conversion.

[0064] [Measurement conditions]

[0065] Developing solvent: Toluene

[0066] Flow rate: 0.35mL / min

[0067] Detector: Refractive Index (RI)

[0068] Chromatographic column: TSK Guardcolumn SuperH-L

[0069] TSKgel SuperH4000(6.0mmI.D.×15cm×1)

[0070] TSKgel SuperH3000(6.0mmI.D.×15cm×1)

[0071] TSKgel SuperH2000(6.0mmI.D.×15cm×2)

[0072] (Both manufactured by TOSOH CORPORATION)

[0073] Column temperature: 40°C

[0074] Sample injection volume: 10 μL (toluene solution with a concentration of 0.5 wt%)

[0075] Component (A) may be used alone or in combination of two or more thereof. When two or more silicate compounds are used in combination, the silicate compound represented by formula (1) and the silicate compound represented by formula (2) may be used separately, or the silicate compound represented by formula (1) and the silicate compound represented by formula (2) may be used in combination.

[0076] The prepared silicate compound can be 29Si-NMR is used to confirm the structure. (A) component is alkaline, and if it is measured directly, the NMR test tube may be damaged. Therefore, it is preferred to use dilute hydrochloric acid to neutralize and then perform NMR measurement. Specifically, after using a small amount of excessive dilute hydrochloric acid to neutralize (A) component, the water layer is separated, and then KYOWAAD 500 (Kyowa Chemical Industry Co., Ltd. manufactures) is used to adsorb and neutralize excess hydrochloric acid. Then, after filtering with a membrane filter, a rotary evaporator is used, and the solvent is distilled off under reduced pressure. Then, a sample for NMR measurement is prepared. For example, it is possible to measure under the following conditions using deuterated chloroform as a solvent.

[0077] [Measurement conditions]

[0078] Determination solvent: deuterated chloroform

[0079] Sample concentration: 30wt%

[0080] Measuring device: JNM-ECX-400 (manufactured by JEOL Ltd.)

[0081] Scan times: 2,000 times

[0082] [Ingredient B]

[0083] The component (B) is an aprotic organic solvent having a relative dielectric constant of 10.0 or less, and functions as a swelling agent for the silicone rubber and a solvent for the component (A).

[0084] The relative dielectric constant of the aprotic organic solvent of the component (B) must be 10.0 or less. If the relative dielectric constant exceeds 10.0, the compatibility with the component (A) will decrease, and sometimes the components (A) and (B) will separate or the solubility of the silicone rubber will deteriorate. The lower limit of the relative dielectric constant of the aprotic organic solvent of the component (B) is not particularly limited, and can be, for example, 1.0 or more.

[0085] The aprotic organic solvent of component (B) may be exemplified by: linear or branched saturated aliphatic hydrocarbons such as hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, eicosane, normal paraffins, isoparaffins, etc.; aromatic hydrocarbons such as benzene, toluene, xylene, trimethylbenzene, ethylbenzene, diethylbenzene, triethylbenzene, propylbenzene, dipropylbenzene, tripropylbenzene, isopropylbenzene, diisopropylbenzene, triisobutylbenzene, etc.; methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, propyl acetate, etc. Ester compounds such as ester, isopropyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, butyl butyrate; dialkyl ether compounds such as diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, dipentyl ether, dihexyl ether, dioctyl ether; glycol ether compounds such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, polyethylene glycol dimethyl ether, diethylene glycol diethyl ether; alicyclic ether compounds such as tetrahydrofuran, tetrahydropyran, 1,4-dioxane, etc., particularly preferably saturated aliphatic hydrocarbons and aromatic hydrocarbons. Specifically, preferred organic solvents include decane, dodecane, normal paraffins, isoparaffins, toluene, and xylene.

[0086] The organic solvent of component (B) may be any organic solvent selected from the above group, but preferably has a boiling point of 50° C. to 300° C., more preferably 65° C. to 250° C., and more preferably 80° C. to 200° C. If the boiling point is 50° C. or higher, the volatility of the organic solvent is low, the environmental burden is not increased, and the operating environment is not deteriorated. If the boiling point is 300° C. or lower, the solvent can be recovered and recycled from the solution after the dissolution step by distillation or the like.

[0087] The amount of the aprotic organic solvent having a relative dielectric constant of 10.0 or less as component (B) is 10 to 99 mass % based on the total amount of the silicate compound represented by the following general formula (1) and / or (2) blended with (A).

[0088] The component (B) may be used alone or in combination of two or more.

[0089] <Dissolution conditions of silicone resin>

[0090] Preferably, the integrated molded product of the silicone resin and the substrate cut into a size that is easy to be impregnated is impregnated in the prepared silicone resin dissolving agent. However, it is also possible to directly impregnate without cutting. The size, thickness, state, etc. of the molded product are not particularly limited. If it is cut into a size of 1mm to 500mm on one side, preferably cut into 2mm to 300mm, and more preferably cut into 5mm to 100mm, it becomes easy to stir using a stirring blade, etc., so it is suitable.

[0091] At this time, even if only the integrally molded product of the silicone resin and the substrate is immersed in the silicone resin solvent, it will be fully dissolved, but stirring using a stirring blade of a dynamic mixer, stirring using a stirring bar of a magnetic stirrer, vibration treatment using a vibrator, ultrasonic treatment, etc. are effective in increasing the dissolution rate, and stirring using a dynamic mixer or a magnetic stirrer is particularly preferred.

[0092] The weight ratio of the silicone resin dissolving agent to the integrally molded article of the silicone resin and the substrate is not particularly limited, but it is preferred to use an amount of the dissolving agent that completely immerses the molded article.

[0093] The dissolution temperature is not particularly limited as long as it is a temperature below the boiling point of the organic solvent used, and may be 10° C. to 200° C., preferably 15° C. to 180° C., and more preferably 20° C. to 150° C. If the temperature is lower than 10° C., the dissolution rate of the silicone rubber may become extremely slow, and if it exceeds 200° C., damage to the substrate may become greater.

[0094] The dissolution time varies depending on the weight ratio of the silicone coated base fabric to the dissolving solution, the stirring conditions, and the temperature conditions, and it is preferred to select an appropriate time, which is usually 0.2 minutes to 120 minutes, preferably 0.5 minutes to 90 minutes, and more preferably 1 minute to 60 minutes.

[0095] <Silicone resin>

[0096] The silicone resin dissolved by the silicone resin dissolving agent of the present invention is not particularly limited, and silicone rubber can be cited as a preferred example. As a specific example of silicone rubber, all silicone rubbers having siloxane bonds can be applied, such as addition-cured silicone rubber, free radical-cured silicone rubber, condensation-cured silicone rubber or ultraviolet-cured silicone rubber, etc. Further, even if hydrophobic silica, hydrophilic silica, iron oxide, ultramarine, silicone resin, carbon black, glass beads, resin balloons, diatomaceous earth, metal oxide powder, metal powder, metal hydroxide powder are included as fillers, they can also be applied. In addition, even if reaction control agents, antioxidants, adhesion aids, adhesion promoters, plasticizers, flame retardants, etc. are included as additives, they can also be applied.

[0097] <Base material>

[0098] The substrate integrally formed with the silicone resin may include a metal substrate and a resin substrate. As a metal substrate, for example, aluminum, iron, stainless steel (SUS), copper, magnesium, lead, nickel, titanium, zinc, molybdenum and their oxides, their alloys, their platings, etc. may be listed. As a resin substrate, for example, acrylonitrile-butadiene-styrene (ABS) resin, polycarbonate (PC) resin, polyurethane (PU) resin, polystyrene (PS) resin, acrylic resin, polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polyphenylene oxide (PPO) resin, polyphenylene sulfide (PPS) resin, polysulfone (PSU) resin, nylon 6 (PA6) resin, nylon 66 (PA66) resin, polyphthalamide (PPA) resin, polyimide (PI) resin, etc. may be listed.

[0099] In addition, the present invention provides a method for separating a silicone coating from a base fabric, characterized in that the silicone-coated base fabric is immersed in a silicone resin solvent. Examples of the silicone-coated base fabric include silicone-coated base fabrics used in airbags.

[0100] Example

[0101] Hereinafter, the present invention will be specifically described using Examples and Comparative Examples, but the present invention is not limited to these Examples at all.

[0102] <Preparation of silicone solution>

[0103] The catalyst and octamethylcyclotetrasiloxane (D4) were heated at the ratio and reaction conditions described in Tables 1 to 3, and then component (B) was added at 25°C and stirred for 30 minutes to prepare an organosilicon solution. 29 Si-NMR confirmed that the silicone resin solution contained the silicate compound represented by the above general formula (1) and / or (2).

[0104] <Production of integrated molded products of silicone rubber and base material>

[0105] A heat addition curing self-adhesive liquid silicone rubber coating material, i.e., KEG-2052T-A / B (manufactured by Shin-Etsu Chemical Co., Ltd.), was applied to aluminum, SUS, PPS, PA6, PA66, and PBT test pieces in a thickness of 30 to 50 μm. Then, the test pieces were cured by heating at 150° C. for 5 minutes in a heating furnace to produce an integral molded product of silicone rubber and a substrate.

[0106] <Dissolution test of integrated molded product of silicone rubber and base material>

[0107] The produced one-piece molded product of silicone rubber and substrate was cut into about 10 mm squares and placed in a 20 mL eggplant flask. Then, 10.0 g of each prepared solution and a stirrer were placed in an eggplant flask equipped with a cooling tube, and heated at 60°C for 30 minutes using an oil bath while stirring with a magnetic stirrer. After the heating process was completed, it was left to cool to 25°C, and the obtained sample was washed with ion exchange water and acetone, and then dried at 100°C for 1 hour using a dryer. Then, the IR spectrum was measured under the following conditions to confirm the removal of silicone rubber.

[0108] <Confirmation of silicone removal status>

[0109] [IR spectrum measurement conditions]

[0110] The IR of the surface where the silicone rubber and the substrate were bonded was measured using the following apparatus and conditions.

[0111] Device: Spectrum65 Fourier Transform Infrared Spectrometer

[0112] (Made by PerkinElmer)

[0113] Measuring range: 4,000~550cm -1

[0114] Number of measurements: 8 times

[0115] The detection is at 2950cm -1 The case where the peak of Si-CH3 near 2950cm was not detected was evaluated as “×”. -1 The peak of Si-CH3 nearby was evaluated as "0", and the results are shown in Tables 1 to 3.

[0116] <Changes in base material quality>

[0117] Cut various substrates of aluminum, SUS, PPS, PA6, PA66, and PBT into about 10 mm squares, weigh them, and put them into a 20 mL eggplant flask. Then, put 10.0 g of each pre-prepared solution and stirrer into an eggplant flask equipped with a cooling tube, stir with a magnetic stirrer, and heat at 60 ° C for 30 minutes in an oil bath. After the heating process is completed, cool it to 25 ° C, wash the obtained sample with ion exchange water and acetone, and use a dryer to dry it at 100 ° C for 1 hour. Then, weigh the obtained sample, calculate the mass change rate, and round it to one decimal place. The results are shown in Tables 1 to 3.

[0118] <Production of silicone coated base fabric>

[0119] 25g / m 2A heat addition curing self-adhesive liquid silicone rubber coating material, i.e., KEG-2052T-A / B (manufactured by Shin-Etsu Chemical Co., Ltd.), was applied to a PA66 base fabric (210 denier) and a PET base fabric (495 denier) in an amount and heat-cured at 200° C. for 1 minute in a drying oven to prepare a silicone-coated base fabric.

[0120] <Dissolution test of silicone coated base fabric>

[0121] The above-mentioned silicone-coated base fabric was cut into 10 mm squares, and 1.0 g was placed in a 20 mL eggplant-shaped flask. Then, 10.0 g of each prepared solution and a stirrer were placed in an eggplant-shaped flask equipped with a cooling tube, and heated at 60°C for 30 minutes using an oil bath while stirring with a magnetic stirrer. After the heating process was completed, it was left to cool to 25°C, and the obtained sample was washed with ion exchange water and acetone, and then dried in a dryer at 100°C for 1 hour. Then, the removal status of the silicone rubber was confirmed by IR measurement in the same way as the confirmation of the removal status of the above-mentioned silicone, and the results are shown in Tables 1 to 3. In addition, surface observation using an optical microscope was performed under the following conditions to confirm the dissolution status of the base fabric.

[0122] <Confirmation of the dissolution status of the base fabric>

[0123] [Surface observation conditions using an optical microscope]

[0124] The surface of the silicone-coated base fabric after the dissolution test, which had been coated with silicone, was observed using an optical microscope using the following apparatus and conditions.

[0125] Device: LEXT OLS5000 (manufactured by OLYMPUS CORPORATION)

[0126] Magnification: 235 times

[0127] The results of observation under an optical microscope were shown in Tables 1 to 3. The case where dissolution of the substrate was observed was evaluated as “×”, and the case where dissolution was not observed was evaluated as “◯”.

[0128] [Table 1]

[0129]

[0130] [Table 2]

[0131]

[0132] [Table 3]

[0133]

[0134] In Examples 1 to 10, there was almost no weight change of various substrates, and the silicone polymer was removed efficiently. By hot-melting the separated substrate, it can be recycled for metal plates, resin plates, various mechanical parts, etc. On the other hand, in Comparative Examples 1 to 12, the silicone rubber could not be removed or the substrate was dissolved. Specifically, in Comparative Example 1 where the A component was insufficient and Comparative Examples 2 to 4 where the relative dielectric constant of the organic solvent was not satisfied, silicone was detected from the substrate. In addition, in Comparative Examples 5 to 12 where the silicate compound did not contain the A component, it was observed that the catalyst was not dissolved or separated, or silicone from the substrate was detected, the substrate was dissolved, and the mass of the substrate changed.

[0135] The present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are examples, and any technical solution having substantially the same structure and achieving the same technical effect as the technical concept described in the claims of the present invention is included in the technical scope of the present invention.

Claims

1. A silicone resin dissolving agent, characterized in that: Include: 1 to 90% by mass of (A) a silicate compound represented by the following general formula (1) and / or (2), [Chemical formula 1] [Chemical formula 2] In the formula, R is independently a group selected from an alkyl group having 1 to 10 carbon atoms and an aryl group having 6 to 10 carbon atoms which is optionally substituted with a halogen atom, M is a cationic species selected from an alkali metal ion, a tetraalkylammonium ion, a benzyltrialkylammonium ion and a tetraalkylphosphonium ion, and n is an integer of 0 to 200; and 99 to 10% by mass of (B) an aprotic organic solvent having a relative dielectric constant of 10.0 or less.

2. The organic silicon resin dissolving agent according to claim 1, characterized in that: The M is a cationic species selected from sodium ion, potassium ion, tetramethylammonium ion, tetrabutylammonium ion or tetrabutylphosphonium ion.

3. The organic silicon resin dissolving agent according to claim 1, characterized in that: All of the R's are methyl groups.

4. A method for separating a silicone coating from a base fabric, characterized in that: The silicone-coated base fabric is immersed in the silicone resin dissolving agent according to any one of claims 1 to 3.

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