Method for producing room-temperature curable organopolysiloxane compositions

Abstract

To provide a method for inexpensively producing a room temperature-curable polyorganosiloxane composition which has low viscosity and high thixotropic properties before curing and whose cured product after curing exhibits high elongation and excellent peelability from an adhesion surface with a substrate.SOLUTION: A method for producing a room temperature-curable organopolysiloxane composition includes the steps of: [i] mixing (A) a linear diorganopolysiloxane in which both molecular chain terminals are blocked with silanol groups, (B) a filler, and (C) 5-95 mass% of the blending amount of a polyether compound to prepare a homogeneous mixture; and [ii] subsequently mixing the mixture prepared in the step [i] with the remainder of the blending amount of the polyether compound (C), (D) a hydrolyzable organosilane compound and / or a partially hydrolyzed condensate thereof, and (E) a curing catalyst to prepare a homogeneous composition.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing a room-temperature curable organopolysiloxane composition that crosslinks and cures by hydrolysis and condensation reactions with moisture (water) in the air at room temperature (23°C ± 15°C) to become a silicone elastomer (rubbery elastomer). Specifically, the composition before curing has a low viscosity and high thixotropic properties such that it does not sag even when applied to a vertical surface, and the cured product after curing has high rubber elasticity and provides a silicone rubber cured product with excellent peelability from the adhesion surface with the substrate.

Background Art

[0002] Room-temperature curable silicone rubber compositions that crosslink and cure by moisture (water) in the air to become silicone elastomers are easy to handle, and the cured products (silicone rubbers) are excellent in weather resistance and electrical properties, so they are used in various fields such as sealing materials for building materials and adhesives in the electrical and electronic fields. Depending on the application, there are cases where the room-temperature curable silicone rubber composition is applied to a vertical surface, and high thixotropic properties such that the applied composition does not sag from the application surface are also required. On the other hand, when repairing or replacing parts of an article to which a room-temperature curable silicone rubber composition has been applied, it may be necessary to remove and peel the cured product of the composition from the adhesion surface with the substrate. In this case, it is required that no cured product remains on the substrate surface and that interfacial peeling occurs. Particularly regarding applications to concrete, it is difficult to completely peel the cured product from the adherent surface due to reasons such as use in an outdoor environment, application not only to horizontal surfaces but also to vertical surfaces, and different surface shapes for each individual.

[0003] Japanese Patent Publication No. 2005-082734 (Patent Document 1) describes how, for electrode coating materials, a diorganopolysiloxane with both ends sealed with dialkoxymonoorganosilyl groups or a polyorganosiloxane with both ends sealed with trialkoxysilyl groups is used as a base polymer, and by combining it with a polyorganosiloxane that does not contain silanol groups, trialkoxy groups, or dialkoxy groups, surface-treated silica as a filler, a bifunctional alkoxysilane or its partially hydrolyzed condensate as a crosslinking agent, and a titanium chelate catalyst, a room-temperature curable organopolysiloxane composition is described that achieves both adhesion and peelability.

[0004] Furthermore, Japanese Patent Publication No. 6-329915 (Patent Document 2) describes that a room-temperature curable silicone composition useful as a masking or packing material, which contains an organopolysiloxane compound modified with polyoxyethylene chains and / or polyoxypropylene chains, has good peelability.

[0005] However, when considering the use of room-temperature curable silicone compositions on vertical surfaces, not only is peelability after curing required, but workability (low viscosity) and high thixotropy are also needed during application (when the composition is applied to the substrate). Achieving both low viscosity and thixotropy in the composition is difficult, and providing peelability after curing is even more challenging. As a result, there were no room-temperature curable silicone compositions that possessed all of these characteristics. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2005-082734 [Patent Document 2] Japanese Patent Application Publication No. 6-329915 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Therefore, the present invention aims to provide an inexpensive method for producing a room-temperature curable polyorganosiloxane composition in which the composition before curing has low viscosity and high thixotropy, and the cured product has high elongation and excellent peelability from the adhesion surface to substrates with different surface shapes depending on the solid, such as concrete. [Means for solving the problem]

[0008] The inventors of this invention conducted diligent research to solve the above-mentioned problems and found that incorporating a polyether compound is effective. Furthermore, they discovered that dividing and incorporating the polyether compound in two stages is extremely effective, leading to the completion of the present invention.

[0009] In other words, the present invention provides a method for producing the following room-temperature curable organopolysiloxane composition. [1] (A) Linear diorganopolysiloxane in which both ends of the molecular chain are sealed with silanol groups: 100 parts by mass, (B) Filler: 1 to 1,000 parts by mass, (C) Polyether compound: 0.5 to 20 parts by mass, (D) Hydrolyzable organosilane compounds and / or partially hydrolyzed condensates thereof: 0.1 to 30 parts by mass, and (E) Curing catalyst: 0.001~15 parts by mass A method for producing a room-temperature curable organopolysiloxane composition containing, [i] A step of mixing 5 to 95% by mass of the above-mentioned blending amounts of component (A), component (B), and component (C) to prepare a homogeneous mixture, then, [ii] A method for producing a room-temperature curable organopolysiloxane composition, comprising the step of mixing the mixture prepared in step [i] with the remainder of the amount of component (C), component (D), and component (E) to prepare a homogeneous composition. [2] A method for producing a room-temperature curable organopolysiloxane composition according to [1], wherein the filler of component (B) contains aerosolized silica and / or calcium carbonate. [Effects of the Invention]

[0010] The room-temperature curable organopolysiloxane composition obtained by the manufacturing method of the present invention has low viscosity and high thixotropy before curing, and after curing it exhibits high elongation and excellent peelability from the adhesion surface to substrates with different surface shapes, such as concrete. Therefore, the room-temperature curable organopolysiloxane composition obtained by the manufacturing method of the present invention is particularly suitable as a sealant for building materials used in outdoor environments or applied to vertical surfaces. [Modes for carrying out the invention]

[0011] The present invention will be described in detail below, but the present invention is not limited to these descriptions.

[0012] (A) component In the method for producing a room-temperature curable organopolysiloxane composition of the present invention, component (A), used as the base polymer of the room-temperature curable organopolysiloxane composition, is a basically linear diorganopolysiloxane (main component) in which both ends of the molecular chain are sealed with silanol groups (hydroxyl groups bonded to silicon atoms).

[0013] As for the linear diorganopolysiloxane of component (A), a linear diorganopolysiloxane represented by the following formula (1), in which both ends of the molecular chain are sealed with silanol groups, is preferred. [ka] (In formula (1), R is independently an unsubstituted or substituted alkyl group having 1 to 12 carbon atoms or an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, and Y is independently an oxygen atom or a divalent hydrocarbon group having 1 to 8 carbon atoms. m is the number at which the viscosity of this diorganopolysiloxane at 23°C is 100 to 1,000,000 mPa·s, and is an average value of 30 to 2,000, preferably 50 to 1,200, and more preferably 100 to 800.)

[0014] The viscosity of the organopolysiloxane represented by the above formula (1) at 23°C is preferably 100 to 1,000,000 mPa·s, particularly preferably 300 to 100,000 mPa·s.

[0015] Note that the viscosity is a measured value by a rotational viscometer (for example, BL type, BH type, BS type, cone plate type, etc.) (hereinafter, the same). Further, the repeating number (m) or degree of polymerization of the diorganosiloxane unit in the organopolysiloxane represented by the above formula (1) is determined as the number average degree of polymerization (or number average molecular weight) in terms of polystyrene in gel permeation chromatography (GPC) analysis using toluene or the like as a developing solvent.

[0016] In the above formula (1), examples of the unsubstituted or substituted alkyl group having 1 to 12 carbon atoms or the unsubstituted or substituted aryl group having 6 to 10 carbon atoms for R include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, etc.; cycloalkyl groups such as cyclopentyl group, cyclohexyl group, etc.; aryl groups such as phenyl group, tolyl group, xylyl group, α-, β-naphthyl group, etc.; and groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as F, Cl, Br, etc. or cyano group, etc., for example, 3-chloropropyl group, 3,3,3-trifluoropropyl group, 2-cyanoethyl group, etc. Among these, alkyl groups such as methyl group and ethyl group are preferable, and methyl group is particularly preferable.

[0017] In the above formula (1), Y is an oxygen atom or a divalent hydrocarbon group having 1 to 8 carbon atoms, and is preferably an oxygen atom, -(CH2CH2) q -, or -(CH=CH) q -(where q represents 1 to 4). Among these, an oxygen atom, -CH2CH2-, or -CH=CH- is particularly preferable.

[0018] Examples of the structure of the linear diorganopolysiloxane represented by the above formula (1) include linear diorganopolysiloxane blocked with silanol groups at both ends of the molecular chain, linear diorganopolysiloxane blocked with diorganohydroxysilylethyl groups at both ends of the molecular chain, linear diorganopolysiloxane blocked with diorganohydroxysilylpropyl groups at both ends of the molecular chain, and the like.

[0019] (A) The linear diorganopolysiloxane blocked with silanol groups at both ends of the molecular chain may be used alone or in combination of two or more having different structures and degrees of polymerization.

[0020] (B) component In the method for producing the room-temperature curable organopolysiloxane composition of the present invention, the room-temperature curable organopolysiloxane composition contains a filler ((B) component) for imparting sufficient mechanical strength to the cured product. Known fillers can be used, for example, dry silica such as calcined silica, pulverized silica, fused silica, fumed silica (pyrogenic silica), silica aerogel, wet silica such as sol-gel silica, precipitated silica, crystalline silica (fine powder quartz), silicon oxides such as diatomaceous earth (silica-based inorganic fillers); metal oxides such as iron oxide, zinc oxide, titanium oxide, or those obtained by subjecting the surfaces thereof to silane treatment; metal carbonates such as calcium carbonate, magnesium carbonate, zinc carbonate; inorganic fillers such as asbestos, glass wool, carbon black, fine powder mica, fused silica powder; synthetic resin powders such as polystyrene, polyvinyl chloride, polypropylene, and the like are used. (B) The filler of the component may be used alone or in combination of two or more.

[0021] The amount of component (B) is 1 to 1,000 parts by mass per 100 parts by mass of component (A), preferably 5 to 200 parts by mass. By adding 1 part by mass or more of component (B), the cured product obtained from the room-temperature curable organopolysiloxane composition will have sufficient mechanical strength. Furthermore, if the amount of component (B) is 1,000 parts by mass or less, the viscosity of the composition will not increase, resulting in poor workability, nor will the rubber strength of the cured product decrease, resulting in deterioration of rubber elasticity.

[0022] (C) Component In the method for producing a room-temperature curable organopolysiloxane composition of the present invention, the room-temperature curable organopolysiloxane composition contains a polyether compound (component (C)) for providing peelability and thixotropy. Examples of these polyether compounds include polyether compounds represented by polyethylene oxide (polyoxyethylene), polypropylene oxide (polyoxypropylene), and ethylene oxide-propylene oxide copolymers (polyoxyethylene-polyoxypropylene copolymers); compounds obtained by modifying (blocking) some or all (one or both terminal hydroxyl groups) of these polyether compounds with alkyl ethers (e.g., polyoxyethylene monoalkyl ether, polyoxypropylene monoalkyl ether, (polyoxyethylene-polyoxypropylene) monoalkyl ether, polyoxyethylene dialkyl ether, polyoxypropylene dialkyl ether, (polyoxyethylene-polyoxypropylene) dialkyl ether); and copolymers of the above polyether compounds with organopolysiloxanes (e.g., block copolymers of polyether and organopolysiloxane, graft copolymers in which organopolysiloxane side chains are grafted onto a polyether main chain, graft copolymers in which polyether side chains are grafted onto an organopolysiloxane main chain, etc.).

[0023] The amount of component (C) is 0.5 to 20 parts by mass, preferably 0.5 to 10 parts by mass, per 100 parts by mass of component (A). By adding 0.5 parts by mass or more of component (C), the room-temperature curable organopolysiloxane composition exhibits thixotropy, and the cured product obtained from the room-temperature curable organopolysiloxane composition becomes peelable. Furthermore, if the amount of component (C) is 20 parts by mass or less, the viscosity decreases drastically and does not adversely affect the thixotropy.

[0024] (C) Regarding the amount of component included, the method for producing the room-temperature curable organopolysiloxane composition of the present invention [i] A step of mixing 5 to 95% by mass of the above blending amounts of component (A), component (B), and component (C) to prepare a homogeneous mixture, and [ii] A step to prepare a homogeneous composition by mixing the mixture prepared in step [i] with the remaining amount of component (C), component (D), and component (E), In both steps [i] and [ii], component (C) is blended in divided portions. When the amount of component (C) is divided, it is preferable that the amount blended in one step (step [i]) is 5 to 95% by mass of the total component (C) (i.e., the amount blended in two steps (step [ii]) is 95 to 5% by mass of the total component (C), and the total for steps [i] and [ii] is 100% by mass), and more preferably that the amount blended in one step (step [i]) is 7 to 90% by mass of the total component (C) (the amount blended in two steps (step [ii]) is 93 to 10% by mass, and the total for steps [i] and [ii] is 100% by mass), and more preferably that the amount blended in one step (step [i]) is 10 to 30% by mass of the total component (C) (the amount blended in two steps (step [ii]) is 90 to 70% by mass, and the total for steps [i] and [ii] is 100% by mass). (C) Regarding the amount of component (C), the amount added in one step (process [i]) is 5 times the total mass of component (C). If there is an extreme difference in the blending amounts between the first step (step[i]) and the second step (step[ii]), such as being less than % or exceeding 95% by mass, sufficient thixotropy and peelability may not be achieved.

[0025] The polyether compound of component (C) may be used alone or in combination of two or more compounds with different structures and degrees of polymerization.

[0026] (D) Component In the method for producing a room-temperature curable organopolysiloxane composition of the present invention, the room-temperature curable organopolysiloxane composition includes, as component (D), a hydrolyzable organosilane compound and / or a partially hydrolyzed condensate thereof that acts as a crosslinking agent (curing agent) to improve the crosslinking density of the cured product, preferably a hydrolyzable organosilane compound and / or a partially hydrolyzed condensate thereof having three or more (particularly three or four) hydrolyzable groups bonded to silicon atoms in the molecule. In the present invention, "partially hydrolyzed condensate" means an organosiloxane oligomer having three or more residual hydrolyzable groups in the molecule, produced by partially hydrolyzing and condensing a hydrolyzable organosilane compound.

[0027] Examples of hydrolyzable groups bonded to silicon atoms in the hydrolyzable organosilane compound of component (D) and / or its partially hydrolyzed condensate include ketoxime groups with 3 to 7 carbon atoms such as dimethylketoxime group, methylethylketoxime group, and diethylketoxime group; alkoxy groups with 1 to 10 carbon atoms such as methoxy group, ethoxy group, propoxy group, isopropoxy group, and butoxy group; acyloxy groups with 2 to 10 carbon atoms such as acetoxy group, octanoyloxy group, and benzoyloxy group; and alkenyloxy groups with 2 to 4 carbon atoms such as vinyloxy group, allyloxy group, propenoxy group, and isopropenoxy group, with alkoxy groups, ketoxime groups, and isopropenoxy groups having 1 to 4 carbon atoms being preferred.

[0028] Examples of organo groups (monovalent hydrocarbon groups) bonded to silicon atoms other than the hydrolyzable group in the hydrolyzable organosilane compound and / or its partially hydrolyzed condensate include alkyl groups having 1 to 10 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups; alkenyl groups having 2 to 10 carbon atoms such as vinyl and allyl groups; and aryl groups having 6 to 10 carbon atoms such as phenyl and tolyl groups, with alkyl groups having 1 to 4 carbon atoms being preferred. Furthermore, in the hydrolyzable organosilane compound and / or its partially hydrolyzed condensate of component (D), it is preferable that the organo groups (monovalent hydrocarbon groups) bonded to silicon atoms other than the hydrolyzable group do not have functional groups having heteroatoms such as nitrogen, sulfur, or oxygen atoms.

[0029] Furthermore, the hydrolyzable organosilane compound of component (D) may be a bissilyl type hydrolyzable silane compound or a trisilyl type hydrolyzable silane compound in which multiple (2 or 3) silyl groups having hydrolyzable groups are linked together by a divalent hydrocarbon group such as an alkylene group.

[0030] Specific examples of component (D) include ketoxime group-containing silanes such as methyltris(methylethylketoxime)silane, vinyltris(methylethylketoxime)silane, phenyltris(methylethylketoxime)silane, and methyltris(dimethylketoxime)silane; alkoxysilanes such as methyltrimethoxysilane, octyltrimethoxysilane, dimethyldimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, and 2-ethylhexyl α-(dimethoxymethylsilyl)propionate; isopropenoxy group-containing silanes such as methyltriisopropenoxysilane, ethyltriisopropenoxysilane, vinyltriisopropenoxysilane, and phenyltriisopropenoxysilane; acetoxysilanes such as methyltriacetoxysilane, ethyltriacetoxysilane, and vinyltriacetoxysilane; and partially hydrolyzed condensates of these silanes. These may be used individually or in combination of two or more.

[0031] The amount of component (D) is 0.1 to 30 parts by mass, preferably 0.2 to 20 parts by mass, and more preferably 0.5 to 15 parts by mass, per 100 parts by mass of component (A). If the amount is 0.1 parts by mass or more, the crosslinking (hardening) reaction will proceed sufficiently, and if the amount is 30 parts by mass or less, the hardened product will not become too hard and will be economical, so this is preferable.

[0032] (E) Component In the method for producing a room-temperature curable organopolysiloxane composition of the present invention, the room-temperature curable organopolysiloxane composition contains a curing catalyst as component (E) in order to rapidly advance the crosslinking (curing) reaction. Examples of curing catalysts for component (E) include non-metallic organic catalysts and metallic catalysts.

[0033] As the nonmetallic organic catalyst for the curing catalyst, any known catalysts used as curing accelerators for condensation-curing type organopolysiloxane compositions can be used, and are not particularly limited. Examples include phosphazene-containing compounds such as N,N,N',N',N'',N''-hexamethyl-N'''-(trimethylsilylmethyl)-phosphorimidictriamide, amine compounds or salts thereof such as n-octylamine, hexylamine, dodecylamine phosphate, and tetramethylguanidine, quaternary ammonium salts such as benzyltriethylammonium acetate, dialkylhydroxylamines such as dimethylhydroxylamine and diethylhydroxylamine, hydrolyzable silanes and siloxanes having a guanidyl group such as tetramethylguanidylpropyltrimethoxysilane, tetramethylguanidylpropylmethyldimethoxysilane, and tetramethylguanidylpropyltris(trimethylsiloxy)silane, but the nonmetallic organic catalyst is not limited to these. Furthermore, the nonmetallic organic catalyst may be used alone or in combination of two or more types.

[0034] As the metal-based catalyst for the curing catalyst, any known catalysts used as curing accelerators for condensation-curing organopolysiloxanes can be used, and are not particularly limited. For example, alkyltin ester compounds such as dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dioctoate, dioctyltin dineodecanoate, dioctyltin dilaurate, and di-n-butyl-dimethoxytin; titanate esters or titanium chelate compounds such as tetraisopropoxytitanium, tetra-n-butoxytitanium, tetrakis(2-ethylhexoxy)titanium, dipropoxybis(acetylacetonate)titanium, and titanium isopropoxyoctylene glycol; zinc naphthenate, zinc stearate, and zinc-2-ethyl ethyl esters. Examples of metal catalysts include choate, iron-2-ethylhexoate, cobalt-2-ethylhexoate, manganese-2-ethylhexoate, cobalt naphthenate, aluminum alkoleate compounds such as aluminum isopropylate and aluminum sec-butyrate, aluminum chelate compounds such as aluminum alkyl acetate diisopropylate and aluminum bisethylacetoacetate monoacetylacetonate, and lower fatty acid salts of alkali metals such as potassium acetate, sodium acetate, and lithium oxalate, but metal catalysts are not limited to these. Furthermore, metal catalysts may be used individually or in combination of two or more types.

[0035] The amount of curing catalyst component (E) is 0.001 to 15 parts by mass, preferably 0.01 to 10 parts by mass, per 100 parts by mass of component (A). If the amount of component (E) is too high, the curing will be too fast, resulting in insufficient working time and potentially being economically disadvantageous.

[0036] -Other additives- Furthermore, in the method for producing the room-temperature curable organopolysiloxane composition of the present invention, in addition to the components (A) to (E) described above, the room-temperature curable organopolysiloxane composition may further contain at least one known additive selected from pigments, dyes, antioxidants, antioxidants, antistatic agents, flame retardants such as antimony oxide and paraffin chloride, viscosity modifiers such as unfunctionalized diorganopolysiloxanes such as trimethylsilyl group-blocked dimethylpolysiloxane (unfunctionalized dimethyl silicone oil), etc., to the extent that it does not impair the objectives of the present invention. Furthermore, antifungal agents, antibacterial agents, etc. may also be added to the extent that it does not impair the objectives of the present invention.

[0037] [Method for producing room-temperature curable organopolysiloxane compositions] In the present invention, a room-temperature curable organopolysiloxane composition is produced by the following method. That is, with respect to the above-mentioned components (A) to (E), [i] A step of mixing 5 to 95% by mass of the above-mentioned blending amounts of component (A), component (B), and component (C) to prepare a homogeneous mixture, then, [ii] A step to prepare a homogeneous composition by mixing the mixture prepared in step [i] with the remaining amount of component (C), component (D), and component (E). It is manufactured by a manufacturing method that includes steps [i] and [ii].

[0038] Furthermore, there are no particular restrictions on the order in which optional components—other additives—are added as needed, but it is preferable that they be added in step [ii].

[0039] In step [i], it is sufficient that components (A), (B), and (C) are thoroughly mixed until 5 to 95% by mass of the above blending amounts are uniform. The mixing conditions are typically 10 minutes to 5 hours, preferably 30 minutes to 3 hours, at room temperature (usually 0 to 40°C, preferably 10 to 30°C) under moisture barrier conditions. Furthermore, it is preferable to perform the mixing under normal pressure or reduced pressure.

[0040] In step [ii], the mixture obtained in step [i] by mixing 5 to 95% by mass of the above-mentioned amounts of components (A), (B), and (C) is mixed with the remaining amount of component (C), components (D), and (E). The conditions for mixing are to heat the mixture at room temperature or to about 40 to 120°C as needed, under moisture barriers, and the mixing time should be sufficient to ensure that the above components are homogenized, usually 10 minutes to 3 hours, preferably 30 minutes to 3 hours. Furthermore, it is preferable to perform the mixing under normal pressure or reduced pressure.

[0041] The room-temperature curable organopolysiloxane composition produced as described above undergoes a rapid crosslinking (curing) reaction at room temperature (23°C ± 15°C) due to atmospheric moisture, yielding cured organopolysiloxane products such as cured silicone rubber (elastomer elastic material) or cured silicone gel. Furthermore, the room-temperature curable organopolysiloxane composition produced as described above has low viscosity, excellent workability, high thixotropy that prevents dripping even when applied to vertical surfaces, and the cured product (cured silicone rubber or cured silicone gel) exhibits high release properties, even on concrete and other materials with varying surface shapes. [Examples]

[0042] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following examples, the compositions were prepared at 23°C, and the viscosity is a measurement taken with a rotational viscometer at 23°C. Room temperature refers to 23°C. Molecular weight is the number-average molecular weight in polystyrene terms obtained by gel permeation chromatography (GPC) analysis using an HLC-8320 manufactured by Tosoh Techno Systems Co., Ltd. with toluene or THF as the developing solvent.

[0043] [Example 1] 80 parts by mass of dimethylpolysiloxane with a viscosity of 5,000 mPa·s, where both ends of the molecular chain are encapsulated with hydroxyl groups (silanol groups) bonded to silicon atoms (corresponding to R=methyl group, Y=oxygen atom, and m=approximately 400 in formula (1) above), 20 parts by mass of dimethylpolysiloxane with a viscosity of 1,500 mPa·s, where both ends of the molecular chain are encapsulated with hydroxyl groups (silanol groups) bonded to silicon atoms (corresponding to R=methyl group, Y=oxygen atom, and m=approximately 260 in formula (1) above), 0.5 parts by mass of dibutyl ether (molecular weight; 2,000) of polyoxyethylene-polyoxypropylene copolymer, and 10 parts by mass of fumetic silica (MU-215, manufactured by Shin-Etsu Chemical Co., Ltd.) were added and the mixture was uniformly mixed at room temperature for 40 minutes under moisture barrier conditions to prepare the mixture (step [i]). Next, 5.0 parts by mass of methyltris(methylethylketoxime)silane, 2.0 parts by mass of vinyltris(methylethylketoxime)silane, 0.1 parts by mass of dioctyltin dilaurate, and 4.5 parts by mass of dibutyl ether (molecular weight; 2,000) of polyoxyethylene-polyoxypropylene copolymer were added to the mixture, and after mixing at room temperature for 10 minutes, the mixture was mixed under reduced pressure for 15 minutes to obtain composition 1 (step [ii]).

[0044] [Example 2] In the manufacturing method of Example 1, step [i] involves polyoxyethylene polyoxypropyl Composition 2 was obtained in the same manner as in Example 1, except that 0.5 parts by mass of monobutyl ether of polyoxyethylene-polyoxypropylene copolymer (molecular weight; 2,000) was used instead of 0.5 parts by mass of dibutyl ether of polyoxyethylene copolymer (molecular weight; 2,000) and 4.5 parts by mass of monobutyl ether of polyoxyethylene-polyoxypropylene copolymer (molecular weight; 2,000) was used instead of 4.5 parts by mass of dibutyl ether of polyoxyethylene-polyoxypropylene copolymer (molecular weight; 2,000) in step [ii].

[0045] [Example 3] Composition 3 was obtained in the same manner as in Example 1, except that in step [i], 0.5 parts by mass of polyether-modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd.; KF-6020) was used instead of 0.5 parts by mass of dibutyl ether of polyoxyethylene-polyoxypropylene copolymer (molecular weight; 2,000), and in step [ii], 4.5 parts by mass of polyether-modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd.; KF-6020) was used instead of 4.5 parts by mass of dibutyl ether of polyoxyethylene-polyoxypropylene copolymer (molecular weight; 2,000).

[0046] [Comparative Example 1] Composition 4 was obtained in the same manner as in Example 1, except that 0.5 parts by mass of dibutyl ether of polyoxyethylene-polyoxypropylene copolymer (molecular weight: 2,000) was not used in step [i] and 4.5 parts by mass of dibutyl ether of polyoxyethylene-polyoxypropylene copolymer (molecular weight: 2,000) was not used in step [ii].

[0047] [Comparative Example 2] Composition 5 was obtained in the same manner as in Example 1, except that in the manufacturing method of Example 1, 5.0 parts by mass of dibutyl ether of polyoxyethylene / polyoxypropylene copolymer (molecular weight; 2,000) was used instead of 0.5 parts by mass of dibutyl ether of polyoxyethylene / polyoxypropylene copolymer (molecular weight; 2,000) in step [i], and 4.5 parts by mass of dibutyl ether of polyoxyethylene / polyoxypropylene copolymer (molecular weight; 2,000) was not used in step [ii].

[0048] [Comparative Example 3] Composition 6 was obtained in the same manner as in Example 1, except that in the manufacturing method of Example 1, 0.5 parts by mass of dibutyl ether of polyoxyethylene-polyoxypropylene copolymer (molecular weight: 2,000) was not used in step [i], and in step [ii], 5.0 parts by mass of dibutyl ether of polyoxyethylene-polyoxypropylene copolymer (molecular weight: 2,000) was used instead of 4.5 parts by mass of dibutyl ether of polyoxyethylene-polyoxypropylene copolymer (molecular weight: 2,000).

[0049] [Comparative Example 4] Composition 7 was obtained in the same manner as in Example 3, except that in the manufacturing method of Example 3, 5.0 parts by mass of polyether-modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd.; KF-6020) was used instead of 0.5 parts by mass of polyether-modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd.; KF-6020) in step [i], and 4.5 parts by mass of polyether-modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd.; KF-6020) was not used in step [ii].

[0050] [Comparative Example 5] Composition 8 was obtained in the same manner as in Example 3, except that 0.5 parts by mass of polyether-modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd.; KF-6020) was not used in step [i], and 5.0 parts by mass of polyether-modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd.; KF-6020) was used in step [ii] instead of 4.5 parts by mass of polyether-modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd.; KF-6020).

[0051] [Comparative Example 6] In the manufacturing method of Example 1, all components blended in steps [i] and [ii] are used in step [ Composition 9 was obtained in the same manner as in Example 1, except for the formulation in [i]. Composition 9 odor As a result, the blended components were not uniformly mixed and dispersed, and many aggregates were observed, making it impossible to accurately evaluate the physical properties.

[0052] [Physical property evaluation test] The viscosity of each composition prepared in Examples 1-3 and Comparative Examples 1-5 immediately after preparation was measured using a BS-type rotational viscometer. Fluidity (slump) was measured in accordance with JIS A-1439, with ○ indicating no fluidity and × indicating fluidity. The results are shown in Table 1.

[0053] [Table 1]

[0054] As shown in Table 1, Examples 1-3 and Comparative Example 5 exhibited low viscosity and thixotropy. On the other hand, no thixotropy was observed in Comparative Examples 1-3, and Comparative Example 4 showed a very high viscosity compared to Example 3, which uses the same polyether component.

[0055] Each composition prepared in Examples 1-3 and Comparative Examples 1-5 was extruded into a 2 mm thick sheet, exposed to air at 23°C and 50% RH, and then left in the same atmosphere for 7 days. The properties of the cured product (initial properties; elongation at the breaking point and maximum strength) were measured in accordance with JIS K-6249 to evaluate its rubber elasticity. Furthermore, the release properties were checked by applying each composition to mortar, exposing it to air at 23°C and 50% RH for 7 days, and then pulling the edge of the hardened material by hand. ○ indicated complete detachment, △ indicated partial adhesion or fracture before detachment, and × indicated complete adhesion. These results are shown in Table 2.

[0056] [Table 2]

[0057] As shown in Table 2, Examples 1-3 and Comparative Example 4 exhibited rubber elasticity and peelability. On the other hand, Comparative Examples 1-3 and 5 did not peel completely.

Claims

1. (A) Linear diorganopolysiloxane in which both ends of the molecular chain are sealed with silanol groups: 100 parts by mass, (B) Filler: 1 to 1,000 parts by mass, (C) Polyether compound: 0.5 to 20 parts by mass, (D) Hydrolyzable organosilane compounds and / or partially hydrolyzed condensates thereof: 0.1 to 30 parts by mass, and (E) Curing catalyst: 0.001 to 15 parts by mass A method for producing a room-temperature curable organopolysiloxane composition containing, [i] A step of preparing a homogeneous mixture by mixing 5 to 95% by mass of the above-mentioned blending amounts of component (A), component (B), and component (C) at 0 to 40°C, then, A method for producing a room-temperature curable organopolysiloxane composition, comprising the step of mixing the mixture prepared in step [i] with the remainder of the amount of component (C), component (D), and component (E) to prepare a homogeneous composition.

2. A method for producing a room-temperature curable organopolysiloxane composition according to claim 1, wherein the filler of component (B) contains aerosolized silica and / or calcium carbonate.

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