ORGANOPOLYSILOXANE COMPOUND, ROOM-TEMPERATURE-CURABLE ORGANOPOLYSILOXANE COMPOSITION, AND ARTICLE

Abstract

Provided are: a novel organopolysiloxane compound represented by general formula (1); a room temperature-curable organopolysiloxane composition which contains said compound and a hydrolyzable organosilane compound having a cycloalkenyl oxysilyl group and / or a partially hydrolyzed condensate thereof, has curing properties equivalent to those of conventional products even when various catalysts are used, reduces harmfulness to the human body and environmental load, and has favorable rubber physical properties, moisture resistance, and LLC resistance after curing; and various articles having said composition or a cured product of said composition.

Description

[Technical Field]

[0001] The present invention relates to a novel organopolysiloxane compound in which hydrolyzable silyl groups of a specific structure are bonded to the molecular chain terminals via silalkylene bonds, and to a condensation-cure, room-temperature-curable organopolysiloxane composition containing this compound as a base polymer, which crosslinks (cures) through a hydrolysis-condensation reaction in the presence of atmospheric moisture (water) at room temperature (23°C±15°C). In particular, the present invention relates to a room-temperature-curable organopolysiloxane composition in which the elimination compound generated from the base polymer and crosslinking agent by the hydrolysis reaction during curing is a cyclic ketone compound such as cyclopentanone, which cures well through a condensation-cure reaction and gives a silicone rubber cured product (elastomeric organopolysiloxane cured product) with excellent adhesiveness, and to various articles containing this composition or its cured product (silicone rubber). [Background technology]

[0002] Room-temperature-curable organopolysiloxane compositions that cure at room temperature to form silicone rubber have long been known and have been widely used in industry. Known room-temperature curing mechanisms include curing via a hydrosilylation addition reaction, radical curing via ultraviolet light, and curing via a condensation reaction between a silicon-bonded hydrolyzable group and a hydroxyl group. Among these, room-temperature-curable organopolysiloxane compositions that cure via a condensation reaction have the advantage of being easily cured at room temperature and less susceptible to curing inhibition by impurities, as occurs in hydrosilylation addition reactions. For these reasons, they are widely used in fields such as automotive gaskets and sealants, construction sealants, and electrical and electronic components. Furthermore, in response to the recent trend toward electrification in various industries, the cured products of room-temperature-curable organopolysiloxane compositions used as sealants and adhesives are required to have properties such as moisture resistance during heating and long-life coolant resistance (LLC resistance).

[0003] Room-temperature-curable organopolysiloxane compositions that cure via a condensation reaction contain a hydrolyzable organosilane compound having a hydrolyzable group as a curing agent (crosslinking agent), and widely used curing agents include deoxime-type hydrolyzable organosilane compounds that release oxime compounds such as 2-butanone oxime upon curing, and dealcohol-type hydrolyzable organosilane compounds that release alcohol compounds such as methanol. The rubber-like cured products obtained by curing room-temperature-curable organopolysiloxane compositions containing these curing agents have high heat resistance, chemical resistance, and weather resistance inherent to the silicone (siloxane structure). On the other hand, oxime compounds such as 2-butanone oxime that are generated during curing of deoxime-type curing agents are suspected of being carcinogenic and are therefore undesirable, and methanol and other compounds that are generated during curing of dealcohol-type curing agents are toxic to the human body and designated as deleterious substances, making them undesirable from the perspective of human health. Furthermore, these room-temperature-curable organopolysiloxane compositions sometimes use tin catalysts as curing catalysts, which are subject to increasingly stringent regulations as environmentally hazardous substances, making them undesirable from the perspective of environmental protection.

[0004] Furthermore, the curing agents (crosslinking agents) used in the dealcohol-free room-temperature-curable organopolysiloxane compositions are less reactive than the curing agents used in the oxime-free room-temperature-curable organopolysiloxane compositions, and therefore have the disadvantage of being inferior in curability to the oxime-free type. From the perspectives of environmental protection and minimizing health hazards, there is a particular desire for products that not only improve performance but also take environmental and safety into consideration, and there is a growing demand for room-temperature-curable organopolysiloxane compositions that have excellent performance and contain highly safe elimination compounds.

[0005] JP 2018-515634 A (Patent Document 1) proposes a condensation-curable organopolysiloxane composition containing a silane compound as a crosslinking agent, which eliminates and releases an α-hydroxycarboxylic acid ester compound, typically ethyl lactate, as an alternative to dealcohol-removing and oxime-removing curing agents. In this system, the leaving group, ethyl lactate, is a highly safe compound, but the use of a tin catalyst is essential. Tin catalysts have been known to be harmful to aquatic organisms, and their use is undesirable from an environmental protection perspective.

[0006] Japanese Patent Publication No. 51-39673 (Patent Document 2) proposes a condensation-curable organopolysiloxane composition that releases a ketone compound, typically acetone. Compared to 2-butanone oxime or methanol, acetone is a compound that is less harmful to the human body. Furthermore, the composition provides a silicone rubber cured product that cures faster and has superior durability compared to conventional curing methods. However, acetone has a low flash point of -20°C and is highly volatile, which limits the environment in which it can be used.

[0007] Japanese Patent No. 5997778 (Patent Document 3) discloses a dealcohol-curable room-temperature-curable organopolysiloxane composition that has improved curability and moisture resistance by using an organosilicon compound having an alkoxysilyl-ethylene bond at the terminal as the base polymer. However, this room-temperature-curable organopolysiloxane composition releases methanol, a toxic gas, during curing, which is undesirable from the standpoint of protecting the human body and the environment. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Special Publication No. 2018-515634 [Patent Document 2] Special Publication No. 51-39673 [Patent Document 3] Patent No. 5997778 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in view of the above circumstances, and provides a novel organopolysiloxane compound suitable as a base polymer for room-temperature-curable organopolysiloxane compositions, which have terminals (and side chains) capped with specific hydrolyzable silyl groups (cycloalkenyloxysilyl groups) in which a cyclic ketone compound such as cyclopentanone is used as the leaving group (leaving compound), and which has a relatively high flash point and no reported health hazards such as carcinogenicity or reproductive toxicity to the human body or environmental hazards such as toxicity to aquatic organisms. The present invention also provides a novel organopolysiloxane compound suitable as a base polymer for room-temperature-curable organopolysiloxane compositions, which have terminals (and side chains) capped with specific hydrolyzable silyl groups (cycloalkenyloxysilyl groups) in which a cyclic ketone compound such as cyclopentanone is used as the leaving group (leaving compound). The present invention aims to provide a room-temperature-curable organopolysiloxane composition that has the same curing properties as conventional products even when using various catalysts, is less harmful to the human body and less burdensome to the environment, and has good rubber properties, moisture resistance, and LLC resistance after curing, by using a hydrolyzable organosilane compound having a specific hydrolyzable group (cycloalkenyloxy group) in which the compound serves as a leaving group (leaving compound) and / or a partial hydrolysis condensate thereof as a crosslinking agent, and that has the same curing properties as conventional products even when using various catalysts, is less harmful to the human body and less burdensome to the environment, and has good rubber properties, moisture resistance, and LLC resistance after curing, as well as various articles that use this composition or a cured product (silicone rubber) obtained by curing this composition. [Means for solving the problem]

[0010]

[0003] As a result of extensive research to achieve the above-mentioned object, the present inventors have discovered that a room-temperature-curable organopolysiloxane composition comprising a base polymer made of a novel organopolysiloxane compound represented by the following general formula (1), in which the terminals (and side chains) are capped with hydrolyzable groups (cycloalkenyloxysilyl groups) that release a cyclic ketone compound, such as cyclopentanone, as a leaving group (leaving compound), via a silalkylene bond, and a hydrolyzable organosilane compound and / or a partial hydrolyzed condensate thereof as a crosslinking agent, which has a specific hydrolyzable group (cycloalkenyloxy group) with a cyclic ketone compound, such as cyclopentanone, as the leaving group (leaving compound), can solve the above-mentioned problems of toxicity to the human body and the environment and safety. They have also discovered that this composition has excellent moisture resistance and LLC resistance, and that even when an organic compound containing titanium, guanidine, or the like is added as a curing catalyst, the composition exhibits curability and cured product performance equivalent to that when a tin catalyst is added. This discovery led to the completion of the present invention. [ka] (In the formula, R 1 , R 2 are unsubstituted or substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms, and may be the same or different groups. n is independently an integer of 2 to 10, m is independently an integer of 1 to 8, l is independently 2 or 3 for each silicon atom to which it is bonded, a is an integer of 50 to 3,000, and b is an integer of 0 to 10.

[0011] Specifically, the present invention provides an organopolysiloxane compound represented by the following general formula (1): a room-temperature-curable organopolysiloxane composition containing the organopolysiloxane compound as a base polymer; and various articles (adhesives, sealants, potting agents, coating agents, etc.) containing the composition or a cured product thereof. [1] An organopolysiloxane compound represented by the following general formula (1): [ka] (In the formula, R1 , R 2 are unsubstituted or substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms, and may be the same or different groups. n is independently an integer of 2 to 10, m is independently an integer of 1 to 8, l is independently 2 or 3 for each silicon atom to which it is bonded, a is an integer of 50 to 3,000, and b is an integer of 0 to 10. [2] (A) 100 parts by mass of an organopolysiloxane compound represented by the following general formula (1): [ka] (In the formula, R 1 , R 2 are unsubstituted or substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms, and may be the same or different groups. n is independently an integer of 2 to 10, m is independently an integer of 1 to 8, l is independently 2 or 3 for each silicon atom to which it is bonded, a is an integer of 50 to 3,000, and b is an integer of 0 to 10. (B) a hydrolyzable compound represented by the following general formula (2): ( Organo ) Silane compound and / or partial hydrolysis condensate thereof: 1 to 40 parts by mass [ka] (In the formula, R 3 is a monovalent hydrocarbon group having 1 to 10 carbon atoms, m is independently an integer of 1 to 8, and k is 3 or 4. A room-temperature-curable organopolysiloxane composition comprising: [3] The hydrolysis properties of the organopolysiloxane compound of component (A) and component (B) ( Organo ) The room-temperature-curable organopolysiloxane composition according to [2], wherein the silane compound and / or the partial hydrolysis condensate thereof each releases a cyclic ketone compound upon hydrolysis. [4] [3] The room-temperature-curable organopolysiloxane composition according to [3], wherein the cyclic ketone compound is cyclopentanone. [5] The room-temperature-curable organopolysiloxane composition according to any one of [2] to [4], further comprising (C) a curing catalyst: 0.01 to 10 parts by mass per 100 parts by mass of the component (A). [6] The room-temperature-curable organopolysiloxane composition according to [5], wherein the curing catalyst (C) comprises at least one of a tin catalyst, a titanium catalyst, an organic strong base catalyst, and an organic bismuth catalyst. [7] The room-temperature-curable organopolysiloxane composition according to any one of [2] to [6], which does not contain a tin catalyst. [8] Furthermore, (D) a silane coupling agent represented by the following general formula (3) and / or a partial hydrolysis condensate thereof: 0.01 to 10 parts by mass per 100 parts by mass of the component (A): R 4 R 5 c Six 3-c (3) (In the formula, R 4 R is a monovalent hydrocarbon group having 1 to 20 carbon atoms and having at least one functional group containing one or more heteroatoms selected from a nitrogen atom, a sulfur atom, and an oxygen atom. 5 are independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and X is independently a hydrolyzable group. c is 0, 1, or 2. The room-temperature-curable organopolysiloxane composition according to any one of [2] to [7], which contains: [9] Furthermore, (E) inorganic filler: 1 to 500 parts by mass per 100 parts by mass of component (A). The room-temperature-curable organopolysiloxane composition according to any one of [2] to [8], which contains:

[10] The room-temperature-curable organopolysiloxane composition according to [9], wherein component (E) is one or more inorganic fillers selected from calcium carbonate, fumed silica, precipitated silica, carbon black, and aluminum oxide.

[11] An adhesive containing the room-temperature-curable organopolysiloxane composition according to any one of [2] to

[10] .

[12] A sealant containing the room-temperature-curable organopolysiloxane composition according to any one of [2] to

[10] .

[13] A potting agent containing the room-temperature-curable organopolysiloxane composition according to any one of [2] to

[10] .

[14] A coating agent containing the room-temperature-curable organopolysiloxane composition according to any one of [2] to

[10] . [Effects of the Invention]

[0012] In the room-temperature-curable organopolysiloxane composition of the present invention, the compound (elimination compound) generated from the base polymer and crosslinking agent by the hydrolysis reaction during curing is a highly safe cyclic ketone compound such as cyclopentanone, and the composition gives a silicone rubber cured product (elastomeric organopolysiloxane cured product) that has excellent curability and adhesive properties after curing, as well as good durability. Therefore, the composition can be suitably used as a variety of adhesives, sealants, potting agents, coating agents, etc., taking into consideration human health and safety. Furthermore, the room-temperature-curable organopolysiloxane composition of the present invention uses as a base polymer a novel organopolysiloxane compound having, at the molecular chain terminal (or also on the side chain), a hydrolyzable silyl group (cycloalkenyloxysilyl group) that releases a cyclic ketone compound as a leaving group via a silalkylene bond, and uses, in combination as a crosslinking agent, a hydrolyzable organosilane compound having a hydrolyzable group (cycloalkenyloxy group) that releases a cyclic ketone compound as a leaving group and / or a partial hydrolysis condensate thereof, thereby exhibiting high moisture resistance and LLC resistance, and can therefore be suitably used as a variety of adhesives, sealants, potting agents, coating agents, etc. that take environmental protection (burden reduction) into consideration. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention is described in detail below. In the present invention, viscosity is measured using a rotational viscometer in accordance with the method specified in JIS Z 8803. In the term "room temperature curable organopolysiloxane composition," "room temperature" refers to a temperature of 23°C ± 15°C and a humidity of 50% RH ± 5% RH.

[0014] [Organopolysiloxane Compound] The novel organopolysiloxane compound of the present invention is represented by the following general formula (1): [ka] (In the formula, R 1 , R 2 are unsubstituted or substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms, and may be the same or different groups. n is independently an integer of 2 to 10, m is independently an integer of 1 to 8, l is independently 2 or 3 for each silicon atom to which it is bonded, a is an integer of 50 to 3,000, and b is an integer of 0 to 10.

[0015] In the above formula (1), R 1 R is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms, and examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, 2-ethylhexyl, nonyl, and decyl; cycloalkyl groups such as cyclohexyl; alkenyl groups such as vinyl, allyl, propenyl, isopropenyl, butenyl, and hexenyl; aryl groups such as phenyl and tolyl; and aralkyl groups such as benzyl and phenylethyl. Alternatively, examples include groups in which the hydrogen atoms of these hydrocarbon groups are partially substituted with halogen atoms such as chlorine, fluorine, and bromine, such as a trifluoropropyl group. 1 The unsubstituted or substituted monovalent hydrocarbon group of R is preferably one that does not contain an aliphatic unsaturated bond, and specifically, an alkyl group such as a methyl group, or an aryl group such as a phenyl group is more preferred, with a methyl group being particularly preferred. 1may be the same group or different groups.

[0016] In the above formula (1), R is a substituent bonded to a silicon atom on the hydrolyzable silyl group (cycloalkenyloxysilyl group) at the molecular chain terminal. 2 is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, particularly a monovalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, preferably a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 7 to 10 carbon atoms; 2 Examples of the alkyl group include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, 2-ethylhexyl, nonyl, and decyl; alkenyl groups such as vinyl, allyl, propenyl, isopropenyl, butenyl, and hexenyl; aryl groups such as phenyl and tolyl; and aralkyl groups such as benzyl and phenylethyl. Alternatively, groups in which the hydrogen atoms of these hydrocarbon groups are partially substituted with halogen atoms such as chlorine, fluorine, and bromine, such as trifluoropropyl, are also included. Among these, methyl, ethyl, and phenyl groups are preferred, with methyl and ethyl being particularly preferred.

[0017] In the above formula (1), the difunctional diorganosiloxane unit (SiR 1 2O 2 / 2 a, which indicates the number of repetitions (or degree of polymerization) of the formula (a), is an integer of 50 to 3,000, preferably an integer of 50 to 2,000, more preferably an integer of 100 to 1,500, and particularly preferably an integer of 200 to 1,200. In the present invention, the degree of polymerization (or molecular weight) can be determined, for example, as the polystyrene-equivalent number-average degree of polymerization (or number-average molecular weight) in gel permeation chromatography (GPC) analysis using toluene, tetrahydrofuran (THF), or the like as a developing solvent.

[0018] In the above formula (1), b, which represents a side chain branched structure, is an integer of 0 to 10, preferably an integer of 0 to 8, more preferably an integer of 0 to 4, and particularly preferably an integer of 0 to 2. The repeating units shown in parentheses with a and b may be bonded randomly.

[0019] In the above formula (1), n, which represents the chain length of the silalkylene bond, is independently an integer of 2 to 10, preferably an integer of 2 to 8, more preferably an integer of 2 to 6, and particularly preferably 2.

[0020] In the above formula (1), m is independently an integer of 1 to 8, preferably an integer of 2 to 6, more preferably an integer of 2 to 4, and even more preferably 2 or 3. When m is 0, a cyclic structure is not formed. When m is an integer exceeding 8, it becomes difficult to purify the starting organosilicon compound having a hydrosilyl group and a hydrolyzable group.

[0021] In the above formula (1), l is independently 2 or 3 for each silicon atom to which it is bonded. If this number is less than 2, rubber curing by a crosslinking reaction does not occur, making the polymer unsuitable as a base polymer for room-temperature-curable organopolysiloxane compositions.

[0022] The organopolysiloxane compound represented by the formula (1) preferably has a viscosity at 23°C of 20 to 1,000,000 mPa·s, more preferably 100 to 300,000 mPa·s, even more preferably 1,000 to 200,000 mPa·s, and particularly preferably 10,000 to 100,000 mPa·s.

[0023] The leaving group (leaving compound) generated by hydrolysis of the organopolysiloxane compound represented by formula (1) above is a cyclic ketone compound such as cyclopropanone, cyclobutanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, cyclononanone, or cyclodecanone, preferably cyclobutanone or cyclopentanone, and more preferably cyclopentanone. There have been no reported cases of cyclobutanone or cyclopentanone being harmful to human health, such as carcinogenicity or reproductive toxicity, or environmental toxicity, such as toxicity to aquatic life. Furthermore, cyclopentanone is mass-produced industrially, is readily available, and is highly cost-competitive, making it advantageous for the production of organopolysiloxane compounds represented by formula (1), as described below.

[0024] The organopolysiloxane compound of the present invention represented by general formula (1) can be produced, for example, as shown in the following formula [1], by subjecting an organopolysiloxane having alkenyl groups at the molecular chain terminals (and side chains) to a hydrosilylation addition reaction using a platinum catalyst with an organosilicon compound having a hydrolyzable group with a hydrosilyl group and a cyclic ketone compound as a leaving group. [ka]

[0025] Examples of organopolysiloxanes having alkenyl groups at the molecular chain terminals (and side chains) include the following: [ka] (In the formula, a is the same as above. b' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 4, and particularly preferably 1 or 2.)

[0026] Examples of organosilicon compounds having a hydrolyzable group with a hydrosilyl group and a cyclic ketone compound as the leaving group include the compounds shown below. [ka] [ka]

[0027] Here, an organosilicon compound having a hydrolyzable group with a hydrosilyl group and a cyclic ketone compound as a leaving group can be produced, for example, by reacting a chlorosilane compound with a cyclic ketone compound in the presence of a catalyst and a basic substance (e.g., dehydrochlorination reaction).

[0028] In the production of organosilicon compounds having a hydrolyzable group with a hydrosilyl group and a cyclic ketone compound as a leaving group, examples of chlorosilane compounds include those shown below. [ka]

[0029] In the production of an organosilicon compound having a hydrolyzable group with a hydrosilyl group and a cyclic ketone compound as a leaving group, examples of the cyclic ketone compound include those shown below. [ka]

[0030] In the production of organosilicon compounds having a hydrolyzable group with a hydrosilyl group and a cyclic ketone compound as a leaving group, the amount of the cyclic ketone compound added to react with the chlorosilane compound is preferably 0.95 to 3.0 mol, more preferably 0.99 to 2.5 mol, and even more preferably 1.0 to 2.0 mol, per mol of chlorine atoms in the chlorosilane compound. If the amount of the cyclic ketone compound added is too small, the reaction may not be completed, whereas if the amount of the cyclic ketone compound added is too large, purification may take a long time, resulting in an increase in production time.

[0031] In the production of organosilicon compounds having a hydrolyzable group with a hydrosilyl group and a cyclic ketone compound as a leaving group, examples of catalysts used in the reaction include monovalent or divalent metallic copper compounds, such as copper chloride, copper bromide, copper iodide, copper sulfate, copper nitrate, copper carbonate, basic copper carbonate, copper formate, copper acetate, and copper butyrate, but are not limited to these. The amount of catalyst (metallic copper compound) added is preferably 0.001 to 0.5 mol, more preferably 0.002 to 0.2 mol, and even more preferably 0.003 to 0.1 mol, per mol of the chlorosilane compound. If the amount of catalyst added is too small, the reaction may not be completed, whereas if the amount of catalyst added is too large, it is disadvantageous in terms of cost.

[0032] In the production of organosilicon compounds having hydrolyzable groups with a hydrosilyl group and a cyclic ketone compound as the leaving group, the basic substance used in the reaction may be a basic substance with low nucleophilicity, such as trimethylamine, triethylamine, tripropylamine, tributylamine, urea, diazabicycloundecene, diazabicyclononene, etc. Among these, trimethylamine, triethylamine, and tributylamine are preferred, with triethylamine being particularly preferred. The amount of the basic substance added is preferably 0.95 to 2.5 mol, more preferably 0.99 to 2.0 mol, and even more preferably 1.0 to 1.5 mol, per mol of chlorine atoms in the chlorosilane compound. If the amount of the basic substance added is too small, the reaction may not be completed, whereas if the amount of the basic substance added is too large, it is economically disadvantageous.

[0033] In the production of organosilicon compounds having a hydrolyzable group in which a hydrosilyl group and a cyclic ketone compound serve as a leaving group, commonly used solvents may be used, and examples of such solvents include aromatic hydrocarbons such as toluene, xylene, and benzene; aliphatic hydrocarbons such as pentane, hexane, heptane, nonane, octane, and decane; ethers such as dimethyl ether, methyl ethyl ether, tetrahydrofuran, and dioxane; halogenated hydrocarbons such as perchloroethane, perchloroethylene, trichloroethane, chloroform, and carbon tetrachloride; amides such as dimethylformamide; and esters such as ethyl acetate, methyl acetate, and butyl acetate. The amount of the solvent used is not particularly limited, but is usually in the range of 10 to 500 parts by mass, preferably 30 to 400 parts by mass, and more preferably 50 to 300 parts by mass, per 100 parts by mass of the cyclic ketone compound used.

[0034] In the production of organosilicon compounds having a hydrolyzable group with a hydrosilyl group and a cyclic ketone compound as a leaving group, the reaction conditions for the chlorosilane compound and the cyclic ketone compound are typically 0 to 120°C, preferably 0 to 100°C, at which the chlorosilane compound is added dropwise to the cyclic ketone compound, and the reaction is carried out at 50 to 120°C, preferably 60 to 100°C, for 1 to 48 hours, more preferably 3 to 30 hours. If the reaction temperature is too low, the reaction may not be completed, and if the reaction temperature is too high, the product may become significantly discolored. Furthermore, if the reaction time is too short, the reaction may not be completed, and if the reaction time is too long, productivity is adversely affected. After the reaction is complete, the target product can be purified by distillation under reduced pressure. The degree of pressure reduction is preferably 1×10 -5 ~3,000 Pa, more preferably 1×10 -5 The pressure during purification is preferably 100 to 250°C, more preferably 120 to 230°C. If the pressure during reduction (degree of reduction) is too high, distillation may become difficult. If the temperature during purification is too low, purification by distillation may become difficult, and if it is too high, the reaction product may become discolored or decompose.

[0035] In the production of the organopolysiloxane compound represented by general formula (1), the amount of organosilicon compound having a hydrolyzable group with a hydrosilyl group and a cyclic ketone compound as a leaving group, which is reacted with an organopolysiloxane having alkenyl groups at the molecular chain terminals (and side chains), is preferably 1 to 10 moles, more preferably 1.1 to 8 moles, and even more preferably 1.2 to 6 moles, per mole of alkenyl group in the organopolysiloxane. If the amount of organosilicon compound is too small, the hydrosilylation addition reaction may not proceed sufficiently (may not be completed), whereas if the amount of organosilicon compound is too large, it may be disadvantageous in terms of cost.

[0036] In the production of the organopolysiloxane compound represented by general formula (1), examples of platinum catalysts used in the reaction include chloroplatinic acid, alcohol solutions of chloroplatinic acid, reaction products of chloroplatinic acid and alcohol, platinum-olefin compound complexes, platinum-vinyl group-containing siloxane complexes, and platinum-supported carbon. The amount of platinum catalyst added is usually preferably 1 to 200 ppm, more preferably 3 to 100 ppm, in terms of platinum atoms (by mass) relative to the total mass of the organopolysiloxane having alkenyl groups at the molecular chain terminals (and side chains) and the organosilicon compound having a hydrolyzable group with a hydrosilyl group and a cyclic ketone compound as the leaving group. If the amount of platinum catalyst is too small, the hydrosilylation addition reaction may not proceed sufficiently (may not be completed), whereas if the amount of platinum catalyst is too large, it may be disadvantageous in terms of cost.

[0037] In producing the organopolysiloxane compound represented by general formula (1), commonly used solvents may be used, and examples of such solvents include aromatic hydrocarbons such as toluene, xylene, and benzene; aliphatic hydrocarbons such as pentane, hexane, heptane, nonane, octane, and decane; ethers such as dimethyl ether, methyl ethyl ether, tetrahydrofuran, and dioxane; halogenated hydrocarbons such as perchloroethane, perchloroethylene, trichloroethane, chloroform, and carbon tetrachloride; amides such as dimethylformamide; and esters such as ethyl acetate, methyl acetate, and butyl acetate. When a solvent is used, the amount used is not particularly limited, but is typically in the range of 10 to 500 parts by mass, preferably 20 to 400 parts by mass, and more preferably 50 to 200 parts by mass, per 100 parts by mass of organopolysiloxane having alkenyl groups at the molecular chain terminals (and side chains).

[0038] In producing the organopolysiloxane compound represented by general formula (1), the reaction conditions for an organopolysiloxane having alkenyl groups at the molecular chain terminals (and side chains) with an organosilicon compound having hydrolyzable groups with hydrosilyl groups and cyclic ketone compounds as leaving groups are typically as follows: the organosilicon compound having hydrolyzable groups with hydrosilyl groups and cyclic ketone compounds as leaving groups is added dropwise to the organopolysiloxane having alkenyl groups at the molecular chain terminals (and side chains) at a temperature of typically 30 to 120°C, preferably 50 to 100°C, and the reaction is allowed to proceed at 40 to 140°C, preferably 60 to 120°C, for 1 to 24 hours, more preferably 4 to 12 hours. If the reaction temperature is too low, the hydrosilylation addition reaction may not proceed sufficiently (may not be completed), whereas if the reaction temperature is too high, the target product may become discolored (turn yellow). If the reaction time is too short, the hydrosilylation addition reaction may not be completed, whereas if the reaction time is too long, productivity may be reduced. After the reaction is complete, the target product can be purified by distillation under reduced pressure. The degree of pressure reduction is preferably 1×10 -5 ~10,000 Pa, more preferably 1×10 -5The pressure during decompression is preferably 120 to 250°C, more preferably 150 to 230°C, and the temperature during purification is preferably 120 to 250°C, more preferably 150 to 230°C. If the pressure during decompression (degree of decompression) is too high, distillation may become difficult. Also, if the temperature during purification is too low, purification by distillation may become difficult, and if it is too high, the reaction product may become discolored or decompose.

[0039] Specific examples of the organopolysiloxane compound of the present invention represented by formula (1) include those represented by the following formula: [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] (wherein a and b' are the same as above.)

[0040] [Room-temperature-curable organopolysiloxane composition] The room-temperature-curable organopolysiloxane composition of the present invention contains the novel organopolysiloxane compound represented by the above-mentioned general formula (1) as the base polymer (component (A)), and a hydrolyzable organosilane compound of a specific structure and / or its partial hydrolysis condensate as the crosslinking agent (component (B)). Each component blended into the room-temperature-curable organopolysiloxane composition is described in detail below.

[0041] [Component (A): Organopolysiloxane compound] The component (A) used in the room-temperature-curable organopolysiloxane composition of the present invention is an organopolysiloxane compound represented by the above-mentioned general formula (1) below. [ka] (In the formula, R 1 , R 2 , n, m, l, a, b are the same as above.)

[0042] As shown in formula (1), component (A) is a diorganopolysiloxane having a linear or branched chain structure, preferably with a viscosity at 23°C of 20 to 1,000,000 mPa·s, in which the main chain consists of repeating diorganosiloxane units and both molecular terminals (and, in some cases, a portion of the molecular side chains) are blocked via silalkylene bonds with hydrolyzable silyl groups (cycloalkenyloxysilyl groups) that use a cyclic ketone compound as the leaving group. This component functions as the main component (base polymer) of the room-temperature-curable organopolysiloxane composition of the present invention and releases a cyclic ketone compound such as cyclopentanone as the leaving group (leaving substance) upon hydrolysis.

[0043] The organopolysiloxane compound of component (A) preferably has a viscosity at 23°C of 20 to 1,000,000 mPa·s, more preferably 100 to 300,000 mPa·s, even more preferably 1,000 to 200,000 mPa·s, and particularly preferably 10,000 to 100,000 mPa·s. If the viscosity of the organopolysiloxane compound is less than the above lower limit (20 mPa·s), a large amount of component (B), described below, will be required, which is economically disadvantageous. On the other hand, if the viscosity of the organopolysiloxane compound exceeds the above upper limit (1,000,000 mPa·s), workability will be reduced, which is undesirable.

[0044] The organopolysiloxane compound of component (A) may use one type alone, or two or more types in combination.

[0045] [Component (B): Hydrolyzable organosilane compound and / or its partial hydrolysis condensate] Component (B) used in the room-temperature-curable organopolysiloxane composition of the present invention is a hydrolyzable organosilane compound represented by the following general formula (2) and / or a partial hydrolysis condensate thereof, which is used as a crosslinking agent (curing agent) and releases a cyclic ketone compound such as cyclopentanone as a leaving group (leaving substance) upon hydrolysis. In the present invention, the term "partial hydrolysis condensate" refers to an organosiloxane oligomer having three or more, preferably four or more, residual hydrolyzable groups in the molecule, which is produced by partial hydrolysis and condensation of the hydrolyzable organosilane compound. [ka] (In the formula, R 3 is a monovalent hydrocarbon group having 1 to 10 carbon atoms, m is independently an integer of 1 to 8, and k is 3 or 4.

[0046] In the above formula (2), R 3is a monovalent hydrocarbon group having 1 to 10 carbon atoms, particularly a monovalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, preferably a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 7 to 10 carbon atoms, 3 Examples of the alkyl group include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, 2-ethylhexyl, nonyl, and decyl, alkenyl groups such as vinyl, allyl, propenyl, isopropenyl, butenyl, and hexenyl, aryl groups such as phenyl and tolyl, and aralkyl groups such as benzyl and phenylethyl. Among these, methyl, ethyl, vinyl, and phenyl groups are preferred, and vinyl and phenyl groups are particularly preferred.

[0047] In the above formula (2), m is independently an integer of 1 to 8, preferably an integer of 2 to 6, more preferably an integer of 2 to 4, and even more preferably 2 or 3. When m is 0, a cyclic structure is not formed. When m is an integer greater than 8, the molecular weight of the hydrolyzable organosilane compound increases, making purification by distillation difficult and increasing the amount added to ensure shelf life, which is disadvantageous in terms of cost.

[0048] In the above formula (2), k is 3 or 4. If this number is less than 3 (i.e., if k is 0, 1, or 2), rubber curing by the crosslinking reaction does not occur, making the compound unsuitable as a crosslinking agent for room-temperature-curable organopolysiloxane compositions.

[0049] The leaving group (leaving compound) generated by hydrolysis of the hydrolyzable organosilane compound represented by the general formula (2) is a cyclic ketone compound such as cyclopropanone, cyclobutanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, cyclononanone, or cyclodecanone, preferably cyclobutanone or cyclopentanone, and more preferably cyclopentanone. There have been no reported cases of cyclobutanone or cyclopentanone being harmful to human health, such as carcinogenicity or reproductive toxicity, or environmental toxicity, such as toxicity to aquatic life. Furthermore, cyclopentanone is mass-produced industrially, is readily available, and is inexpensive, making it advantageous for producing the hydrolyzable organosilane compound of component (B), as described below.

[0050] The hydrolyzable organosilane compound of component (B) can be produced, for example, by reacting a chlorosilane compound corresponding to the hydrolyzable organosilane compound represented by general formula (2) with a cyclic ketone compound in the presence of a catalyst and a basic substance (e.g., dehydrochlorination). This reaction is represented, for example, by the following formula [2]: [ka] (In the formula, R 3 , m, and k are as defined above.)

[0051] Here, examples of the chlorosilane compound include those shown below. [ka]

[0052] Examples of the cyclic ketone compound include the following. [ka]

[0053] The amount of the cyclic ketone compound to be reacted with the chlorosilane compound is preferably 0.95 to 3.0 mol, more preferably 0.99 to 2.5 mol, and even more preferably 1.0 to 2.0 mol, per mol of chlorine atoms in the chlorosilane compound. If the amount of the cyclic ketone compound is too small, the reaction may not be completed, whereas if the amount of the cyclic ketone compound is too large, purification may take a long time, resulting in an increase in production time.

[0054] The catalyst used in the reaction includes monovalent or divalent metallic copper compounds, such as, but not limited to, copper chloride, copper bromide, copper iodide, copper sulfate, copper nitrate, copper carbonate, basic copper carbonate, copper formate, copper acetate, and copper butyrate. The amount of catalyst (metallic copper compound) added is preferably 0.001 to 0.5 mol, more preferably 0.002 to 0.2 mol, and even more preferably 0.003 to 0.1 mol, per mol of the chlorosilane compound. If the amount of catalyst added is too small, the reaction may not be completed, whereas if the amount of catalyst added is too large, it is disadvantageous in terms of cost.

[0055] The basic substance used in the reaction may be a basic substance with low nucleophilicity, such as trimethylamine, triethylamine, tripropylamine, tributylamine, urea, diazabicycloundecene, diazabicyclononene, etc. Among these, trimethylamine, triethylamine, and tributylamine are preferred, with triethylamine being particularly preferred. The amount of the basic substance added is preferably 0.95 to 2.5 mol, more preferably 0.99 to 2.0 mol, and even more preferably 1.0 to 1.5 mol, per mol of chlorine atoms in the chlorosilane compound. If the amount of the basic substance added is too small, the reaction may not be completed, whereas if the amount of the basic substance added is too large, it is economically disadvantageous.

[0056] A commonly used solvent may be used in the production of the hydrolyzable organosilane compound of component (B). Examples of the solvent include organic solvents such as aromatic hydrocarbons such as toluene, xylene, and benzene; aliphatic hydrocarbons such as pentane, hexane, heptane, nonane, octane, and decane; ethers such as dimethyl ether, methyl ethyl ether, tetrahydrofuran, and dioxane; halogenated hydrocarbons such as perchloroethane, perchloroethylene, trichloroethane, chloroform, and carbon tetrachloride; amides such as dimethylformamide; and esters such as ethyl acetate, methyl acetate, and butyl acetate. The amount of the solvent used is not particularly limited, but is usually in the range of 10 to 500 parts by mass, preferably 30 to 400 parts by mass, and more preferably 50 to 300 parts by mass, per 100 parts by mass of the cyclic ketone compound used.

[0057] The reaction conditions for the chlorosilane compound and the cyclic ketone compound are typically 0 to 120°C, preferably 0 to 100°C, at which the chlorosilane compound is added dropwise to the cyclic ketone compound, and the reaction is carried out at 50 to 120°C, preferably 60 to 100°C, for 1 to 48 hours, more preferably 3 to 30 hours. If the reaction temperature is too low, the reaction may not be completed, and if the reaction temperature is too high, the product may become significantly discolored. Furthermore, if the reaction time is too short, the reaction may not be completed, and if the reaction time is too long, productivity is adversely affected. After the reaction is complete, the target product can be purified by distillation under reduced pressure. The degree of pressure reduction is preferably 1×10 -5 ~3,000 Pa, more preferably 1×10 -5 The pressure during purification is preferably 100 to 250°C, more preferably 120 to 230°C. If the pressure during reduction (degree of reduction) is too high, distillation may become difficult. If the temperature during purification is too low, purification by distillation may become difficult, and if it is too high, the reaction product may become discolored or decompose.

[0058] Specific examples of the hydrolyzable organosilane compound of component (B) include those represented by the following formula: [ka]

[0059] The component (B) may be used alone or in combination of two or more. The amount of component (B) blended is 1 to 40 parts by mass, preferably 3 to 30 parts by mass, and more preferably 5 to 20 parts by mass, per 100 parts by mass of component (A). If the amount of component (B) blended is less than the above lower limit of 1 part by mass, shelf life may be impaired when stored in a sealed container. If the amount of component (B) blended exceeds the above upper limit of 40 parts by mass, the curability of the room-temperature-curable organopolysiloxane composition may be significantly reduced, and adhesiveness may also be impaired. The hydrolyzable organosilane compound and / or its partial hydrolysis condensate of component (B) is clearly distinguishable from the silane coupling agent and / or its partial hydrolysis condensate of component (D), an optional component described below, in that it does not contain a monovalent hydrocarbon group having at least one functional group containing one or more heteroatoms selected from a nitrogen atom, a sulfur atom, and an oxygen atom in the molecule.

[0060] [(C) component curing catalyst] The room-temperature-curable organopolysiloxane composition of the present invention may optionally contain a curing catalyst (component (C)). The curing catalyst (C) may be a metallic or non-metallic condensation catalyst that has conventionally been used as a curing accelerator for room-temperature-curable organopolysiloxane compositions. Examples of the catalyst include organic tin compounds (tin catalysts) such as dibutyltin methoxide, dibutyltin diacetate, dibutyltin dioctate, dibutyltin dilaurate, dioctyltin dilaurate, dioctyltin dioctate, dimethyltin dimethoxide, and dimethyltin diacetate; organic titanium compounds (titanium catalysts) such as tetrapropyl titanate, tetrabutyl titanate, tetra-2-ethylhexyl titanate, dimethoxytitanium diacetylacetonate, and titanium diisopropoxybis(ethylacetoacetate); amine compounds such as triethylamine, hexylamine, tetramethylguanidine, and γ-tetramethylguanidylpropyltrimethoxysilane, and salts thereof (organic strong base catalysts); and organic bismuth compounds such as bismuth tris(2-ethylhexanoate) and bismuth tris(neodecanoate), as well as mixtures thereof (organic bismuth catalysts). At least one of these, i.e., one type, can be used alone, or two or more types can be used in combination. In the present invention, among the above catalysts, when any of the titanium catalyst, organic strong base catalyst, and organic bismuth catalyst is blended, the same curability and cured product performance as when a tin catalyst is blended are exhibited. Therefore, from the viewpoint of environmental protection, it is preferable to blend a titanium catalyst, organic strong base catalyst, or organic bismuth catalyst without blending a tin catalyst.

[0061] When component (C) is used, its amount is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 8 parts by mass, and even more preferably 0.1 to 5 parts by mass, per 100 parts by mass of component (A). If the amount of component (E) is less than the lower limit of 0.01 parts by mass, the catalytic effect may not be obtained, whereas if the amount exceeds the upper limit of 10 parts by mass, the storage stability of the composition may be poor.

[0062] [Component (D): Silane coupling agent and / or its partial hydrolysis condensate] The room-temperature-curable organopolysiloxane composition of the present invention may optionally contain a silane coupling agent (component (D)) and / or a partial hydrolysis condensate thereof. Component (D) is a silane coupling agent represented by the following general formula (3) (i.e., a hydrolyzable organosilane compound or carbon functional silane having a functional group-containing monovalent hydrocarbon group) and / or a partial hydrolysis condensate thereof, and is a component for imparting good adhesive properties to the cured product of the room-temperature-curable organopolysiloxane composition of the present invention. R 4 R 5 c Six 3-c (3) (In the formula, R 4 R is a monovalent hydrocarbon group having 1 to 20 carbon atoms and at least one functional group (excluding a guanidyl group) containing one or more heteroatoms selected from a nitrogen atom, a sulfur atom, and an oxygen atom. 5 are independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and X is independently a hydrolyzable group. c is 0, 1, or 2.

[0063] In the above formula (3), R 4is a monovalent hydrocarbon group having 1 to 20 carbon atoms and having at least one functional group containing one or more heteroatoms selected from a nitrogen atom, a sulfur atom, and an oxygen atom (for example, an unsubstituted or substituted amino group, an unsubstituted or substituted imino group, an amido group, a ureido group, a mercapto group, an epoxy group, a (meth)acryloxy group, etc., but excluding a guanidyl group), and specifically, a β-(2,3-epoxycyclohexyl)ethyl group, a β-(3,4-epoxycyclohexyl)ethyl group, a γ-glycidoxypropyl group, a γ-methacryloxypropyl group, a γ-glycid ... Examples of monovalent hydrocarbon groups include monovalent hydrocarbon groups having preferably 3 to 20 carbon atoms, more preferably 3 to 14 carbon atoms, containing at least one heteroatom selected from a nitrogen atom, a sulfur atom, and an oxygen atom, such as a hydroxypropyl group, a γ-acryloxypropyl group, an N-β(aminoethyl)-γ-aminopropyl group [also known as an N-2-(aminoethyl)-3-aminopropyl group], a γ-aminopropyl group, an N-phenyl-γ-aminopropyl group, a γ-ureidopropyl group, a γ-mercaptopropyl group, and a γ-isocyanatopropyl group. 4 As the alkyl group, a γ-glycidoxypropyl group, a γ-aminopropyl group, and an N-β-(aminoethyl)-γ-aminopropyl group are particularly preferred.

[0064] In addition, in the above formula (3), R 5 is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms. Examples include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, 2-ethylhexyl, nonyl, and decyl; cycloalkyl groups such as cyclohexyl; alkenyl groups such as vinyl, allyl, propenyl, isopropenyl, butenyl, and hexenyl; aryl groups such as phenyl and tolyl; and aralkyl groups such as benzyl and phenylethyl. Alternatively, the hydrogen atoms of these hydrocarbon groups may be partially substituted with halogen atoms such as chlorine, fluorine, or bromine, such as trifluoropropyl. Among these, methyl, ethyl, propyl, and isopropyl groups are preferred. R 5 may be the same group or different groups.

[0065] In the above formula (3), examples of the hydrolyzable group X include ketoxime groups, alkoxy groups, alkoxyalkoxy groups, acyloxy groups, and alkenyloxy groups. Specific examples include ketoxime groups having 3 to 8 carbon atoms, such as dimethylketoxime groups, diethylketoxime groups, methylethylketoxime groups, and methylisobutylketoxime groups; alkoxy groups having 1 to 4 carbon atoms, preferably 1 or 2 carbon atoms, such as methoxy groups, ethoxy groups, propoxy groups, isopropoxy groups, butoxy groups, isobutoxy groups, sec-butoxy groups, and tert-butoxy groups; alkoxyalkoxy groups having 2 to 4 carbon atoms, such as methoxymethoxy groups and methoxyethoxy groups; acyloxy groups having 2 to 4 carbon atoms, such as acetoxy groups and propionoxy groups; and alkenyloxy groups having 2 to 4 carbon atoms, such as vinyloxy groups, allyloxy groups, propenoxy groups, and isopropenoxy groups. X is preferably a methoxy group. The hydrolyzable groups X may be the same or different.

[0066] Specific examples of the silane coupling agent represented by formula (3) of component (D) include aminosilanes such as γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and 3-2-(aminoethylamino)propyltrimethoxysilane [also known as N-2-(aminoethyl)-3-aminopropyltrimethoxysilane]; epoxysilanes such as γ-glycidoxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; (meth)acrylic silanes such as γ-(meth)acryloxypropyltrimethoxysilane and γ-(meth)acryloxypropyltriethoxysilane; mercaptosilanes such as γ-mercaptopropyltrimethoxysilane; and isocyanate silanes such as γ-isocyanatepropyltrimethoxysilane.

[0067] The silane coupling agent and / or partial hydrolysis condensate thereof as component (D) may be used alone or in combination of two or more. When component (D) is added, the amount added is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 8 parts by mass, per 100 parts by mass of component (A). If the amount is less than 0.01 part by mass, the cured product may not exhibit sufficient adhesive properties, while if the amount added exceeds 10 parts by mass, the rubber strength after curing may decrease, or the curability may decrease.

[0068] [Component (E): Inorganic filler] The room-temperature-curable organopolysiloxane composition of the present invention may optionally contain an inorganic filler (component (E)). The inorganic filler (component (E)) is a reinforcing or non-reinforcing filler that imparts rubber-like physical properties to the room-temperature-curable organopolysiloxane composition of the present invention. Examples of inorganic fillers for component (E) include silica-based fillers such as dry silica (e.g., calcined silica, fused silica, crushed silica, and fumed silica), wet silica (e.g., precipitated silica and sol-gel silica), and crystalline silica (finely powdered quartz), with or without surface hydrophobic treatment, diatomaceous earth, carbon black, talc, bentonite, calcium carbonate, zinc carbonate, magnesium carbonate, calcium oxide, zinc oxide, magnesium oxide, aluminum oxide, and aluminum hydroxide. Of these, calcium carbonate, fumed silica, precipitated silica, carbon black, and aluminum oxide are preferred, and calcium carbonate, fumed silica, precipitated silica, carbon black, and aluminum oxide whose surfaces have been hydrophobized are more preferred. In this case, it is preferable that these inorganic fillers have a low moisture content. There are no particular limitations on the type, amount, treatment method, etc. of the surface treatment agent (hydrophobic treatment agent), but representative examples include organosilicon compounds such as chlorosilanes, alkoxysilanes, and organosilazanes, as well as fatty acids, paraffins, silane coupling agents, and titanium coupling agents.

[0069] The inorganic filler of component (E) may be used alone or in combination of two or more different types. When component (E) is blended, the blending amount is preferably 1 to 500 parts by mass, more preferably 3 to 300 parts by mass, even more preferably 5 to 200 parts by mass, and particularly preferably 8 to 150 parts by mass, per 100 parts by mass of component (A). If the blending amount is less than 1 part by mass, sufficient rubber strength cannot be obtained, which may result in a problem that the composition is not suitable for the intended use, while if the blending amount exceeds 500 parts by mass, the ejection properties from the cartridge may deteriorate, storage stability may decrease, and the mechanical properties of the resulting rubber may also decrease.

[0070] [Other ingredients] In addition to the above components, the room-temperature-curable organopolysiloxane composition of the present invention may contain commonly known additives, provided that the purpose of the present invention is not impaired. Examples of such additives include polyethers as thixotropy improvers, silicone oils (non-functional organopolysiloxanes) as plasticizers, and isoparaffins. If necessary, colorants such as pigments, dyes, and fluorescent whitening agents, physiologically active additives such as mildew inhibitors, antibacterial agents, and marine life repellents, surface modifiers such as phenylsilicone oils, fluorosilicone oils, and organic liquids incompatible with silicones as bleed oils, volatile oils, and solvents such as low-boiling isoparaffins may also be added.

[0071] The room-temperature-curable organopolysiloxane composition of the present invention can be obtained by uniformly mixing the above-mentioned components and the various additives in predetermined amounts in a dry atmosphere. The room-temperature-curable organopolysiloxane composition of the present invention cures upon standing at room temperature, and known methods and conditions for molding and curing can be used depending on the type of composition.

[0072] The room-temperature-curable organopolysiloxane composition of the present invention, particularly the one-component composition, is readily cured at room temperature (23°C ± 15°C) by storing it in the absence of moisture, i.e., in a sealed container that has been protected from moisture, and exposing it to moisture in the air at the time of use.

[0073] The room-temperature-curable organopolysiloxane composition of the present invention generates compounds from the base polymer and crosslinker through a hydrolysis reaction during curing, such as highly safe cyclic ketone compounds like cyclopentanone, making it safe for humans and the environment. Furthermore, cyclopentanone has a flash point of 35°C, which is higher than dealcohol-type compositions that release alcohol compounds like methanol during curing, making it safer. The room-temperature-curable organopolysiloxane composition of the present invention exhibits good curability when used with various existing catalysts, and the resulting cured product (silicone rubber) also exhibits excellent adhesive properties. Furthermore, the use of catalysts other than tin can provide a composition that is even more environmentally friendly.

[0074] Therefore, the room-temperature-curable organopolysiloxane composition of the present invention is useful as an adhesive, sealing agent, potting agent, coating agent, etc. The room-temperature-curable organopolysiloxane composition of the present invention can be used as an adhesive, sealing agent, potting agent, or coating agent according to a conventionally known method.

[0075] Examples of the target articles include automobile parts, automobile oil seals, electrical and electronic parts, building structures, and civil engineering structures. [Example]

[0076] The present invention will be described in more detail below with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to the following Examples. The viscosity values ​​are measured at 23°C using a rotational viscometer in accordance with the method specified in JIS Z 8803.

[0077] [Synthesis Example 1] Synthesis of Hydrolyzable Organosilane Compound 1 A 5,000 mL four-neck separable flask equipped with a mechanical stirrer, thermometer, reflux condenser, and dropping funnel was charged with 834 g (9.9 mol) of cyclopentanone, 825 g (8.2 mol) of triethylamine, 5 g (0.05 mol) of copper(I) chloride, and 1,500 mL of hexane. 332 g (2.47 mol) of trichlorosilane was added dropwise over approximately 2 hours at 40-60°C. After stirring for 12 hours at 80°C, the resulting triethylamine hydrochloride was filtered off. The hexane was removed from the filtrate by distillation at 100°C and atmospheric pressure. The filtrate was then distilled at 180°C and 300 Pa to obtain hydrolyzable organosilane compound 1 (339 g, 58% yield). This reaction is represented by the following formula [3]. [ka]

[0078] [Synthesis Example 2] Synthesis of organopolysiloxane compound 1 A 1,000 mL four-neck separable flask equipped with a mechanical stirrer, thermometer, reflux condenser, and dropping funnel was charged with 500 g of a linear dimethylpolysiloxane (degree of polymerization: approximately 750) with a viscosity of 28,000 mPa·s and a molecular chain end-capped with silicon-bonded vinyl groups at both ends, and 2 g of a 0.5 wt% toluene solution of a Karstedt catalyst (platinum-olefin compound complex). The mixture was then heated to 80°C. Next, 25 g of hydrolyzable organosilane compound 1 was added dropwise to the dropping funnel over 1 hour. After the dropwise addition, the mixture was allowed to react at 80°C for 6 hours, followed by vacuum distillation at 180°C and 300 Pa for 5 hours to remove the toluene and excess hydrolyzable organosilane compound 1, yielding organopolysiloxane compound 1 (498 g, 95%). The reaction scheme is represented by the following equation [4]. [ka]

[0079] [Synthesis Example 3] Synthesis of organopolysiloxane compound 2 A 1,000 mL four-neck separable flask equipped with a mechanical stirrer, thermometer, reflux condenser, and dropping funnel was charged with 500 g of a linear dimethylpolysiloxane (degree of polymerization: approximately 890) with a viscosity of 31,000 mPa·s, in which both ends of the molecular chain and some of the branched side chains were capped with silicon-bonded vinyl groups, and 2 g of a 0.5 wt% toluene solution of a Karstedt catalyst (platinum-olefin compound complex). The mixture was then heated to 80°C. Next, 30 g of hydrolyzable organosilane compound 1 was added dropwise to the dropping funnel over 1 hour. After the dropwise addition, the mixture was allowed to react at 80°C for 6 hours, followed by vacuum distillation at 180°C and 300 Pa for 5 hours to remove the toluene and excess hydrolyzable organosilane compound 1, yielding organopolysiloxane compound 2 (495 g, 93%). The reaction scheme is represented by the following equation [5]. [ka]

[0080] [Synthesis Example 4] Synthesis of hydrolyzable organosilane compound 2 A 5,000 mL four-neck separable flask equipped with a mechanical stirrer, thermometer, reflux condenser, and dropping funnel was charged with 834 g (9.9 mol) of cyclopentanone, 825 g (8.2 mol) of triethylamine, 5 g (0.05 mol) of copper(I) chloride, and 1,500 mL of hexane. 400 g (2.47 mol) of vinyltrichlorosilane was added dropwise over approximately 2 hours at 40-60°C. After stirring for 12 hours at 80°C, the resulting triethylamine hydrochloride was filtered off. The hexane was removed from the filtrate at 100°C and atmospheric pressure, followed by distillation at 180°C and 300 Pa to obtain hydrolyzable organosilane compound 2 (532 g, 69%). This reaction is represented by the following formula [6]: [ka]

[0081] [Comparative Synthesis Example 1] Synthesis of organopolysiloxane compound 3 A 1,000 mL four-neck separable flask equipped with a mechanical stirrer, thermometer, reflux condenser, and dropping funnel was charged with 500 g of a silanol-terminated linear dimethylpolysiloxane (degree of polymerization: approximately 620) with a viscosity of 20,000 mPa·s and 5 g of triethylamine, and the mixture was heated to 80°C. Next, 40 g of hydrolyzable organosilane compound 2 was added dropwise to the dropping funnel over 1 hour. After the addition, the mixture was reacted at 100°C for 6 hours, followed by vacuum distillation at 180°C and 300 Pa for 5 hours to remove triethylamine and excess hydrolyzable organosilane compound 2, yielding organopolysiloxane compound 3 (492 g, 91%). The reaction scheme is represented by the following equation [7]. [ka]

[0082] [Example 1] To 100 parts by mass of (A-1) the organopolysiloxane compound 1, 10 parts by mass of (E) fumed silica surface-treated with dimethyldichlorosilane (product name: MU-215, manufactured by Shin-Etsu Chemical Co., Ltd.) were added and thoroughly mixed, and then 8 parts by mass of (B) the hydrolyzable organosilane compound 2 were added and thoroughly mixed. Finally, 1 part by mass of (D) γ-aminopropyltrimethoxysilane (product name: KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.1 part by mass of (C-1) dioctyltin dilaurate were added and thoroughly mixed under reduced pressure to obtain composition 1.

[0083] [Example 2] To 100 parts by mass of (A-1) the organopolysiloxane compound 1, 10 parts by mass of (E) fumed silica surface-treated with dimethyldichlorosilane (product name: MU-215, manufactured by Shin-Etsu Chemical Co., Ltd.) were added and thoroughly mixed, and then 8 parts by mass of (B) the hydrolyzable organosilane compound 2 were added and thoroughly mixed. Finally, 1 part by mass of (D) γ-aminopropyltrimethoxysilane (product name: KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.) and 4 parts by mass of (C-2) titanium diisopropoxybis(ethylacetoacetate) (product name: Orgatix TC750, manufactured by Matsumoto Fine Chemical Co., Ltd.) were added and thoroughly mixed under reduced pressure to obtain composition 2.

[0084] [Example 3] To 100 parts by mass of (A-1) the organopolysiloxane compound 1, 10 parts by mass of (E) fumed silica surface-treated with dimethyldichlorosilane (product name: MU-215, manufactured by Shin-Etsu Chemical Co., Ltd.) were added and thoroughly mixed, and then 8 parts by mass of (B) the hydrolyzable organosilane compound 2 were added and thoroughly mixed. Finally, 1 part by mass of (D) γ-aminopropyltrimethoxysilane (product name: KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.6 parts by mass of (C-3) γ-tetramethylguanidylpropyltrimethoxysilane were added and thoroughly mixed under reduced pressure to obtain composition 3.

[0085] [Example 4] To 100 parts by mass of (A-2) the organopolysiloxane compound 2, 10 parts by mass of (E) fumed silica surface-treated with dimethyldichlorosilane (product name: MU-215, manufactured by Shin-Etsu Chemical Co., Ltd.) were added and thoroughly mixed, and then 8 parts by mass of (B) the hydrolyzable organosilane compound 2 were added and thoroughly mixed. Finally, 1 part by mass of (D) γ-aminopropyltrimethoxysilane (product name: KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.1 part by mass of (C-1) dioctyltin dilaurate were added and thoroughly mixed under reduced pressure to obtain composition 4.

[0086] [Example 5] To 100 parts by mass of (A-2) the organopolysiloxane compound 2, 10 parts by mass of (E) fumed silica surface-treated with dimethyldichlorosilane (product name: MU-215, manufactured by Shin-Etsu Chemical Co., Ltd.) were added and thoroughly mixed, and then 8 parts by mass of (B) the hydrolyzable organosilane compound 2 were added and thoroughly mixed. Finally, 1 part by mass of (D) γ-aminopropyltrimethoxysilane (product name: KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.) and 4 parts by mass of (C-2) titanium diisopropoxybis(ethylacetoacetate) (product name: Orgatix TC750, manufactured by Matsumoto Fine Chemical Co., Ltd.) were added and thoroughly mixed under reduced pressure to obtain composition 5.

[0087] [Example 6] To 100 parts by mass of (A-2) the organopolysiloxane compound 2, 10 parts by mass of (E) fumed silica surface-treated with dimethyldichlorosilane (product name: MU-215, manufactured by Shin-Etsu Chemical Co., Ltd.) were added and thoroughly mixed, and then 8 parts by mass of (B) the hydrolyzable organosilane compound 2 were added and thoroughly mixed. Finally, 1 part by mass of (D) γ-aminopropyltrimethoxysilane (product name: KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.6 parts by mass of (C-3) γ-tetramethylguanidylpropyltrimethoxysilane were added and thoroughly mixed under reduced pressure to obtain composition 6.

[0088] [Comparative Example 1] (A') 100 parts by weight of linear dimethylpolysiloxane (degree of polymerization: approximately 620) with a viscosity of 20,000 mPa·s at 23°C and both molecular chain terminals capped with silanol groups (hydroxyl groups bonded to silicon atoms) was added to 10 parts by weight of (E) fumed silica (product name: MU-215, manufactured by Shin-Etsu Chemical Co., Ltd.) whose surface had been treated with dimethyldichlorosilane and mixed thoroughly. Then, 8 parts by weight of (B') methyltrismethylethylketoximesilane was added and mixed thoroughly. Finally, 1 part by weight of (D) γ-aminopropyltrimethoxysilane (product name: KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.1 parts by weight of (C-1) dioctyltin dilaurate were added and mixed thoroughly under reduced pressure to obtain Composition 7.

[0089] Comparative Example 2 (A'') 100 parts by mass of linear dimethylpolysiloxane (degree of polymerization: approximately 620) with a viscosity of 20,000 mPa·s at 23°C and both molecular chain terminals capped with methyldimethoxy groups was added to 10 parts by mass of (E) fumed silica (product name: MU-215, manufactured by Shin-Etsu Chemical Co., Ltd.) whose surface had been treated with dimethyldichlorosilane and mixed thoroughly. Then, 10 parts by mass of (B'') methyltrimethoxysilane was added and mixed thoroughly. Finally, 1 part by mass of (D) γ-aminopropyltrimethoxysilane (product name: KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.) and 4 parts by mass of (C-2) titanium diisopropoxybis(ethylacetoacetate) (product name: Orgatix TC750, manufactured by Matsumoto Fine Chemical Co., Ltd.) were added and mixed thoroughly under reduced pressure to obtain Composition 8.

[0090] Comparative Example 3 (A') 100 parts by weight of linear dimethylpolysiloxane (degree of polymerization: approximately 620) with a viscosity of 20,000 mPa·s at 23°C and both molecular chain terminals capped with silanol groups (hydroxyl groups bonded to silicon atoms) was added to 10 parts by weight of (E) fumed silica (product name: MU-215, manufactured by Shin-Etsu Chemical Co., Ltd.) whose surface had been treated with dimethyldichlorosilane, and mixed thoroughly. Then, 8 parts by weight of (B) the hydrolyzable organosilane compound 2 was added and mixed thoroughly. Finally, 1 part by weight of (D) γ-aminopropyltrimethoxysilane (product name: KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.6 parts by weight of (C-3) γ-tetramethylguanidylpropyltrimethoxysilane were added and mixed thoroughly under reduced pressure to obtain Composition 9.

[0091] Comparative Example 4 To 100 parts by mass of (A''') organopolysiloxane compound 3, 10 parts by mass of (E) fumed silica surface-treated with dimethyldichlorosilane (product name: MU-215, manufactured by Shin-Etsu Chemical Co., Ltd.) were added and thoroughly mixed, and then 8 parts by mass of (B) the hydrolyzable organosilane compound 2 was added and thoroughly mixed. Finally, 1 part by mass of (D) γ-aminopropyltrimethoxysilane (product name: KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.6 parts by mass of (C-3) γ-tetramethylguanidylpropyltrimethoxysilane were added and thoroughly mixed under reduced pressure to obtain composition 10.

[0092] [Test method] The following evaluations were carried out for each of the compositions (room-temperature-curable organopolysiloxane compositions) prepared in Examples 1 to 6 and Comparative Examples 1 to 4. The evaluation results, along with the blending amounts of Examples 1 to 6 and Comparative Examples 1 to 4, are shown in Tables 1 and 2.

[0093] (Initial evaluation) For initial evaluation, the following tack-free time, curing rate, rubber properties, and adhesiveness were evaluated using each composition immediately after preparation.

[0094] Tuck Free Time Using each of the compositions prepared in the above Examples and Comparative Examples, the tack-free time (touch-dry time) was measured according to the method specified in JIS A 5758.

[0095] curing speed The hardening rate test method was to fill a glass petri dish with an inner diameter of 10 mm with each composition prepared in the above Examples and Comparative Examples, and after one day (24 hours) at 23°C and 50% RH, insert a probe into the dish and measure the hardened thickness (depth) from the part exposed to air.

[0096] Rubber properties Each composition prepared in the above Examples and Comparative Examples was poured into a 2 mm mold and cured at 23°C and 50% RH for 7 days to obtain a 2 mm thick rubber sheet. The rubber physical properties (Type A durometer hardness, tensile strength, and elongation at break) were measured in accordance with JIS K 6249.

[0097] Adhesiveness Each composition prepared in the above Examples and Comparative Examples was cured between two aluminum plates measuring 25 mm in width and 100 mm in length at 23°C and 50% RH for 7 days, resulting in a bonded area of ​​2.5 cm2 between the upper and lower aluminum plates. 2 A 1mm thick layer of cured silicone rubber was formed to prepare shear adhesion test specimens. Using each test specimen, the shear adhesive strength and cohesive failure rate to aluminum were measured according to the method specified in JIS K 6249.

[0098] (Heat and humidity resistance evaluation) To confirm the moisture and heat resistance performance, the obtained cured silicone rubber sheet and shear adhesive test specimen were exposed to an environment of 85°C and 85% RH and allowed to deteriorate for 1,000 hours, after which tests (rubber properties, adhesiveness) similar to those performed at the initial stage of production (initial evaluation) were conducted to confirm the moisture and heat resistance.

[0099] (LLC resistance evaluation) To confirm LLC resistance, the obtained cured silicone rubber sheet and shear adhesive test specimen were immersed in a 50:50 mass% solution of Toyota Super Long Life Coolant and tap water, exposed to a 120°C environment, and allowed to deteriorate for 250 hours. After that, the same tests (rubber properties, adhesiveness) as those performed at the initial stage of production (initial evaluation) were conducted to confirm LLC resistance.

[0100] [Table 1]

[0101] [Table 2]

[0102] The above results demonstrate that the room-temperature-curable organopolysiloxane compositions of the present invention (Examples 1 to 6) exhibit good curability (tack-free time, cure rate), rubber properties, and adhesion in the initial evaluation, regardless of whether a tin catalyst, titanium catalyst, or strong organic base catalyst is used, and also exhibit good properties in the evaluations of moist heat resistance and LLC resistance. On the other hand, it can be seen that the oxime-free composition of Comparative Example 1 and the dealcohol-free composition of Comparative Example 2 showed a significant decrease in physical properties after evaluation of durability, particularly LLC resistance. Furthermore, even when the compositions using the decyclic ketone-type crosslinking agents of Comparative Examples 3 and 4 were compared with the room-temperature-curable organopolysiloxane composition of the present invention, the difference in the base polymer structure meant that the room-temperature-curable organopolysiloxane composition of the present invention was superior in the evaluation of moist heat resistance and LLC resistance. Furthermore, the compound released during curing from the room-temperature-curable organopolysiloxane compositions of the present invention (Examples 1 to 6) is cyclopentanone, a highly safe compound with no reported health hazards, such as carcinogenicity or reproductive toxicity, to humans, or environmental hazards, such as toxicity to aquatic life. On the other hand, the compounds released during curing from the compositions of Comparative Examples 1 and 2 are both labeled as health hazards in SDSs (safety data sheets) and the like, and include 2-butanone oxime, which is suspected to be carcinogenic and toxic to aquatic life, and methanol, which is designated as a deleterious substance and highly harmful to humans. Furthermore, because methanol has a lower flash point and boiling point than cyclopentanone, the room-temperature-curable organopolysiloxane compositions of the present invention are superior in terms of human health and environmental protection.

[0103] From the above results, it was confirmed that the room-temperature-curable organopolysiloxane composition of the present invention releases safer compounds during curing, has good curing properties even when various catalysts are used, and the cured products have good physical properties, adhesiveness, and durability (moisture and heat resistance, LLC resistance), making it suitable for use in a variety of applications (adhesives, sealants, potting agents, coating agents, etc.).

Claims

1. An organopolysiloxane compound represented by the following general formula (1): 【Chemistry 1】 (In the formula, R 1 , R 2 are unsubstituted or substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms, and may be the same or different groups. n is independently an integer of 2 to 10, m is independently an integer of 1 to 8, l is independently 2 or 3 for each silicon atom to which it is bonded, a is an integer of 50 to 3,000, and b is an integer of 0 to 10.

2. (A) 100 parts by mass of an organopolysiloxane compound represented by the following general formula (1): 【Chemistry 2】 (In the formula, R 1 , R 2 are unsubstituted or substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms, and may be the same or different groups. n is independently an integer of 2 to 10, m is independently an integer of 1 to 8, l is independently 2 or 3 for each silicon atom to which it is bonded, a is an integer of 50 to 3,000, and b is an integer of 0 to 10. (B) a hydrolyzable (organo)silane compound represented by the following general formula (2) and / or a partial hydrolysis condensate thereof: 1 to 40 parts by mass 【Transformation 3】 (In the formula, R 3 is a monovalent hydrocarbon group having 1 to 10 carbon atoms, m is independently an integer from 1 to 8, and k is 3 or 4. A room-temperature-curable organopolysiloxane composition comprising:

3. 3. The room-temperature-curable organopolysiloxane composition according to claim 2, wherein the organopolysiloxane compound of component (A) and the hydrolyzable (organo)silane compound and / or its partial hydrolysis condensate of component (B) each release a cyclic ketone compound upon hydrolysis.

4. 4. The room-temperature-curable organopolysiloxane composition according to claim 3, wherein the cyclic ketone compound is cyclopentanone.

5. 3. The room-temperature-curable organopolysiloxane composition according to claim 2, further comprising: (C) a curing catalyst: 0.01 to 10 parts by weight per 100 parts by weight of component (A).

6. 6. The room-temperature-curable organopolysiloxane composition according to claim 5, wherein the curing catalyst (C) comprises at least one of a tin catalyst, a titanium catalyst, an organic strong base catalyst, and an organobismuth catalyst.

7. 3. The room-temperature-curable organopolysiloxane composition according to claim 2, which does not contain a tin catalyst.

8. Furthermore, (D) a silane coupling agent represented by the following general formula (3) and / or a partial hydrolysis condensate thereof: 0.01 to 10 parts by mass per 100 parts by mass of the component (A): R 4 R 5 c SiX 3-c (3) (In the formula, R 4 R is a monovalent hydrocarbon group having 1 to 20 carbon atoms and at least one functional group containing one or more heteroatoms selected from a nitrogen atom, a sulfur atom, and an oxygen atom. 5 are independently unsubstituted or substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms, and X is independently a hydrolyzable group. c is 0, 1, or 2.

3. The room-temperature-curable organopolysiloxane composition according to claim 2, comprising:

9. 3. The room-temperature-curable organopolysiloxane composition according to claim 2, further comprising (E) an inorganic filler in an amount of 1 to 500 parts by weight per 100 parts by weight of component (A).

10. 10. The room-temperature-curable organopolysiloxane composition according to claim 9, wherein component (E) is one or more inorganic fillers selected from the group consisting of calcium carbonate, fumed silica, precipitated silica, carbon black, and aluminum oxide.

11. An adhesive comprising the room-temperature-curable organopolysiloxane composition according to any one of claims 2 to 10.

12. A sealant containing the room-temperature-curable organopolysiloxane composition according to any one of claims 2 to 10.

13. A potting agent comprising the room-temperature-curable organopolysiloxane composition according to any one of claims 2 to 10.

14. A coating agent comprising the room-temperature-curable organopolysiloxane composition according to any one of claims 2 to 10.

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