Organopolysiloxane and method for the preparation thereof

Abstract: An MQ organopolysiloxane compatible with organic plastics, has an epoxy-containing organic group, and has the following general formula R¹ represents monovalent hydrocarbon groups, R² represents the hydrogen atom and monovalent hydrocarbon groups, R³ represents epoxy-containing organic groups and alkoxysilylalkyl groups, a is 0 or a positive number, b and c are positive numbers, a / c has a value of 0 to 4, b / c has a value of 0.05 to 4, and ( a + b )/ c has a value of 0.872 to 4. Also, a method for the preparation of this organopolysiloxane comprises an addition reaction of an Si-H containing organopolysiloxane with an epoxy-containing compound in the presence of a hydrosilylation catalyst.

Description: The present invention relates to an organopolysiloxane and to a method for its preparation. More specifically, the present invention relates to an organopolysiloxane comprising monofunctional siloxane units (M unit) and tetrafunctional siloxane units (Q unit) and that also has an epoxy-containing organic group. Various types of MQ organopolysiloxanes are already known in the art. Shirahata in U.S. Patent No. 4,707,531, issued November 17, 1992, describes a method of making MQ organopolysiloxanes which have long been used as starting materials for varnishes and pressure-sensitive adhesives. According to Shirahata an alkyl silicate is dripped into a mixture of an aqueous hydrochloric acid which contains at least 5 weight percent hydrogen chloride and a trialkylsilane or a disiloxane at a temperature of 0° to 90°C. Shirahata and Fukutani in U.S. Patent No. 4,946,921, issued August 7, 1990, describe a hydroxyphenyl-containing MQ organopolysiloxane of the general formula where A is a hydroxyphenyl group, R' is an alkylene group having 1 to 4 carbon atoms, n is zero or one, R'' is an alkyl group having 1 to 4 carbon atoms, x and z are positive numbers, y is zero or a positive number, x , y , and z have values such that their ratios are 0 < ( x + y )/ z< 4, and zero <y / x< 5. Fukutani in U.S. Patent No. 5,011,901, issued April 30, 1991, describes a chloromethyl-containing MQ organopolysiloxane of the general formula where R' is a monovalent hydrocarbon group having 1 to 6 carbon atoms, R" is a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, x and z are positive numbers, y is zero or a positive number, and x , y , and z have values such that their ratios are 0.3 < ( x + y )/ z< 4 and zero <y / x< 100. However, the groups that may be bonded to the silicon atom in the monofunctional siloxane units (M unit) in the above-referenced MQ organopolysiloxanes are limited to the hydrogen atom, alkyl groups, alkenyl groups, the hydroxyphenyl group, and the chloromethyl group. There have been no reports to date of MQ organopolysiloxane in which the silicon atom of the monofunctional siloxane unit (M unit) carries an epoxy-containing organic group. It was known from an article published in Journal of Polymer Science Part A: Polymer Chemistry Edition 28 (1990), February, No. 3, New York, US, that silicon containing epoxide can be synthesized by a photoinitiated cationic polymerisation of silicon-containing epoxy resins. One example is the reaction of tetrakis(dimethylsiloxy)silane and 3-vinyl-oxabicyclo[4.1.0]-heptane. Chujo et al. teach in Polymer Journal 16 (1984) No. 6, Tokyo, Japan, pages 495 to 504, that polymerizable methacryl-olyl- or epoxy-end silicone oligomers can be prepared from water glass and an epoxy group-containing silane. GB-A 834 326 is concerned with a process for the preparation of organosilicone compounds which have attached to at least one silicon atom by a silicon carbon linkage at least one organic radical containing at least one epoxide group, where the remaining valences of the silicon atoms are satisfied by hydrocarbon radicals, halogenated hydrocarbon radicals, hydrocarbonoxy radicals, halohydrocarbonoxy radicals, hydroxylol radicals, hydrogen atoms or oxygen atoms. GB-A 2 084 598 teaches ultraviolet curable silicone adhesives which require the addition of ultraviolet light sensitive catalyst which is effective for initiating the cure of the composition. EP-A 0 473 995 (a post-published document) teaches epoxy functionalized siloxane resin copolymers which are used as controlled release additives. EP-A 0 476 426 (which is also a post-published document) teaches the preparation of epoxy silicone compounds using rhodium catalysts. The present inventor achieved the present invention as the result of extensive efforts directed at solving the aforementioned problem. The present invention takes as its object the introduction of organopolysiloxane having monofunctional siloxane units (M unit) and tetrafunctional siloxane units (Q unit) and which also has an epoxy-containing organic group. A further object of the present invention is the introduction of a method for the preparation of this organopolysiloxane. This invention relates to a composition comprising an organopolysiloxane having an epoxy-containing organic group wherein said organopolysiloxane is represented by the following general formula wherein R 1 is a non-alkenyl monovalent hydrocarbon group, each R 2 is independently selected from a hydrogen atom or a non-alkenyl monovalent hydrocarbon group, each R 3 is an epoxy-containing organic group, each R 4 is an alkoxysilylalkyl group, a is 0 or a positive number, b' , b'' and c are positive numbers, a / c has a value of 0 to less than 4, ( b' + b" )/ c has a value of 0.05 to 4 and ( a + b' + b'' )/ c has a value of 0.2 to 4. This invention also relates to a method for producing an organopolysiloxane having an epoxy-containing organic group comprising reacting in the presence of (A) a hydrosilylation-reaction catalyst, with (B) an SiH-containing organopolysiloxane with the general formula R 1 is a non-alkenyl monovalent hydrocarbon group, d is 0 or a positive number, e and f are positive numbers, d / f has a value of 0 to 4, e / f has a value of 0.05 to 4, and ( d + e )/ f has a value of 0.2 to 4, (C) an aliphatically unsaturated epoxy-containing organic compound, and (D) an alkoxysilylalkene. The MQ organopolysiloxane according to the present invention contains at least 1 epoxy-containing organic group in each molecule and is represented by the following general formula R 1 in this formula represents non-alkenyl monovalent hydrocarbon groups, and it is specifically exemplified by alkyl groups such as methyl, ethyl, propyl, and butyl; aryl groups such as phenyl and tolyl; aralkyl groups such as benzyl and phenylethyl; and haloalkyl groups such as chloromethyl and 3,3,3-trifluoropropyl. R 2 represents the hydrogen atom and non-alkenyl monovalent hydrocarbon groups, and it is specifically exemplified by the hydrogen atom and by alkyl groups such as methyl, ethyl, propyl, and butyl; aryl groups such as phenyl and tolyl; aralkyl groups such as benzyl and phenylethyl; and haloalkyl groups such as chloromethyl and 3,3,3-trifluoropropyl. R 3 represents epoxy-containing organic groups and R 4 alkoxysilylalkyl groups. The epoxy-containing organic groups are specifically exemplified by glycidoxyethyl, glycidoxypropyl, glycidoxybutyl, 3,4-epoxycyclohexylethyl, 3,4-epoxycyclohexylpropyl, 3,4-epoxynorbornanylethyl, and 2-(3,4-epoxy-3-methylcyclohexyl)-2-methylethyl, and the alkoxysilylalkyl groups are specifically exemplified by trimethoxysilylethyl, triethoxysilylethyl, and methyldimethoxysilylethyl. The subscript a represents the number of monofunctional siloxane units (M unit) that lack epoxy-containing organic groups, and it may be 0 or a positive number. The subscript b ' is a positive number that represents the number of monofunctional siloxane units (M unit) that contain epoxy-containing organic groups and the subscript b " is a positive number that represents M units that contain alkoxy-silylalkyl groups. The subscript c is a positive number that represents the number of tetrafunctional siloxane units (Q unit). According to this invention the following ratios for these subscripts are a / c = 0 to 4, b + b "/ c = 0.05 to 4, and ( a + b ' + b ")/ c = 0.2 to 4. The bases for these ratios are as follows: more than 4 monofunctional siloxane units (M unit) cannot be present per tetrafunctional siloxane unit (Q unit), and at least 0.05 monofunctional siloxane units (M unit) having an epoxy-containing organic group or alkoxysilylalkyl group must be present per tetrafunctional siloxane unit (Q unit) in order for the organopolysiloxane according to the present invention to he highly compatible with organic resins. The MQ organopolysiloxane according to the present invention is liquid or solid at room temperature. While its molecular weight is not specifically restricted, the molecular weight preferably falls into the range of 500 to 500,000 in order to obtain good miscibility with organic resins. The hydrosilylation-reaction catalyst (also known as addition reaction) comprising component (A) is a catalyst for the addition reaction between the silicon-bonded hydrogens in component (B) and the aliphatically unsaturated bonds in components (C) and (D). The hydrosilylation-reaction catalyst of component (A) is not specifically restricted as long as it is a compound that may ordinarily be employed as a hydrosilylation-reaction catalyst. It is specifically exemplified by platinum compounds, rhodium compounds, and palladium compounds. Platinum compounds are particularly preferred. Said platinum compounds are specifically exemplified by chloroplatinic acid, alcohol solutions of chloroplatinic acid, the complexes of platinum and aliphatically unsaturated hydrocarbon compounds, platinum/divinyldisiloxane complexes, platinum black, and platinum/active carbon. Component (A) should be added in a catalytic quantity. Its quantity of addition is not specifically restricted; however, for the example of a platinum compound as component (A), the preferred addition is 0.01 to 500 ppm as platinum metal atoms in component (A) based on the organopolysiloxane comprising component (B). The SiH-containing organopolysiloxane comprising component (B) is the main starting material in the present invention, and it is represented by the following general formula R 1 in the preceding formula represents non-alkenyl monovalent hydrocarbon groups, and it is specifically exemplified by alkyl groups such as methyl, ethyl, propyl, and butyl; aryl groups such as phenyl and tolyl; aralkyl groups such as benzyl and phenylethyl; and haloalkyl groups such as chloromethyl and 3,3,3-trifluoropropyl. The subscript d represents the number of SiH-free monofunctional siloxane units (M unit), and it is 0 or a positive number. The subscript e is a positive number that represents the number of SiH-containing monofunctional siloxane units (M unit), and f is a positive number that represents the number of tetrafunctional siloxane units (Q unit). The following ratios obtain for these subscripts: d / f = 0 to 4, e / f = 0.05 to 4, and ( d + e )/ f = 0.2 to 4. The bases for these ratios are as follows: more than 4 monofunctional siloxane units (M unit) cannot be present per tetrafunctional siloxane unit (Q unit), and at least 0.05 SiH-containing monofunctional siloxane units (M unit) must be present per tetrafunctional siloxane unit (Q unit) in order for the organopolysiloxane according to the present invention (organopolysiloxane after introduction of epoxy-containing organic groups or alkoxysilylalkyl) to be highly compatible with organic resins. Component (B) itself can be produced by methods which are known. Methods for the preparation of component (B) are specifically exemplified, inter alia, as follows: cohydrolysis of tetrahalosilane and monohalosilane, cohydrolysis of tetraalkoxysilane and monoalkoxysilane, cohydrolysis of tetraalkoxysilane and tetraorganodisiloxane followed by a re-equilibration polymerization reaction. In a preferred method, tetraalkoxysilane is dripped into a stirred aqueous hydrochloric acid solution of organosilicon compound selected from hexaorganodisiloxane, tetraorganodisiloxane, triorganohalosilane, and diorganohalosilane as described by Shirahata can be used. Shirahata shows a method of preparing these MQ organopolysiloxanes having Si-H. The epoxy-containing aliphatically unsaturated organic compound of component (C) is the component that introduces the epoxy-containing organic group into the organopolysiloxane according to the present invention. Component (C) is specifically exemplified by vinyl glycidyl ether, allyl glycidyl ether, butenyl glycidyl ether, 1,2-epoxy-4-allylcyclosiloxane, 1,2-epoxy-4-vinylcyclohexane, 2,3-epoxy-5-vinylnorbornane, and 1,2-epoxy-1-methyl-4-isopropylcyclohexane. The quantity of addition of component (C) is not specifically restricted in the preparative method according to the present invention. However, when less than 1 aliphatically unsaturated bond from component (C) is present per silicon-bonded hydrogen in component (B), the organopolysiloxane product according to the present invention will be organopolysiloxane that contains both silicon-bonded hydrogen and epoxy-containing organic groups. On the other hand, when 1 or more aliphatically unsaturated bond from component (C) is present per silicon bonded hydrogen in component (B), organopolysiloxane carrying the epoxy-containing organic group is produced that is almost free of silicon-bonded hydrogen. The alkoxysilylalkene component (D) is the component that introduces the alkoxysilylalkyl group into the organopoly-siloxane according to the present invention. Component (D) is specifically exemplified by trimethoxyvinylsilane, methyldi-methoxyvinylsilane, dimethylmethoxyvinylsilane, triethoxy-vinylsilane, methyldiethoxyvinylsilane, and trimethoxyallyl-silane. The addition of component (D) in the preparative method according to the present invention is optional. Component (D) is reacted together with component (C) when the alkoxysilylalkyl group must be introduced into organopolysiloxane according to the present invention. When component (D) is used in the preparative method according to the present invention, the organopolysiloxane product according to the present invention will contain silicon-bonded hydrogen plus the epoxy-containing organic group plus alkoxysilylalkyl when less than 1 aliphatically unsaturated bond from components (C) plus (D) is present per silicon-bonded hydrogen in component (B). On the other hand, when at least 1 aliphatically unsaturated bond from components (C) plus (D) is present per silicon-bonded hydrogen in component (B), the organopolysiloxane product will contain the epoxy-containing organic group and alkoxysilylalkyl but will be substantially free of silicon-bonded hydrogen. The reaction sequence in the preparative method according to the present invention is arbitrary, and the following are provided, inter alia, as examples of the reaction sequence: (a) component (A) is first mixed with component (B); component (C) is then added to the resulting system to yield SiH-containing organopolysiloxane that carries epoxy-containing organic groups; component (D) is subsequently added to the system to yield alkoxysilylalkyl-containing organopolysiloxane that carries epoxy-containing organic groups; (b) component (A) is first mixed with component (B); component (D) is then added to the resulting system to yield SiH-containing, alkoxysilylalkyl-containing organopolysiloxane; component (C) is subsequently added to the system to yield alkoxysilylalkyl-containing organopolysiloxane that carries epoxy-containing organic groups. The reaction temperature is not specifically restricted in the preparative method according to the present invention; however, the reaction temperature preferably falls within the range of 50 to 150°C in order to rapidly complete the addition reaction. Organic solvent can be used in the preparative method according to the present invention. Organic solvents usable by the present invention are specifically exemplified by aromatic solvents such as toluene and xylene; aliphatic solvents such as hexane, heptane, and octane; and ketone solvents such as acetone and methyl ethyl ketone. The invention organopolysiloxane prepared as described above is obtained as a reaction mixture, and it can be purified by distillation of unreacted components (C) and (D) from the product mixture. Because the organopolysiloxane according to the present invention carries epoxy-containing organic groups, it is useful as a physical-property modifier or plasticizer for thermosetting resin compositions based on imide resins, phenolic resins, and epoxy resins, and for thermoplastic resins such as acrylic resins and polyethylene resins. In particular, when the organopolysiloxane according to the present invention is a low-viscosity liquid at room temperature, it is useful as a reactive diluent for organic resins. Organopolysiloxane according to the present invention that contains both epoxy-containing organic groups and alkoxysilylalkyl is useful as an adhesion promoter for curable organopolysiloxane compositions and organic resin coatings and as a starting material for adhesive primer compositions. The present invention will be explained in greater detail below using illustrative examples. The viscosity in the examples is the value measured at 25°C and parts are by weight. The development of the reactions was monitored by infrared spectroscopic analysis. EXAMPLE 1 (Reference Example) 50 Parts of organopolysiloxane (boiling point, 188°C; molecular weight, 328.7) with the following formula, 84 parts allyl glycidyl ether, and 200 weight parts toluene were placed in a 1 L four-neck flask equipped with stirrer, reflux condenser, and thermometer. The water fraction in the system was then azeotropically removed by heating while stirring. After cooling, approximately 10 drops of 2 wt% chloroplatinic acid in isopropanol were dripped into the system, which was then reheated and held at the reflux temperature of toluene for 3 hours with stirring. At this point the absence of silicon-bonded hydrogen in a sample of the reaction mixture was confirmed by infrared spectroscopic analysis. The unreacted allyl glycidyl ether and the toluene were distilled off in vacuo to afford 117.4 parts of a yellowish brown, transparent liquid product. This product had a viscosity of 0.054 Pa.s (Pascal.seconds) and an epoxy equivalent weight of 198 g/eq. The results of nuclear magnetic resonance spectroscopic analysis confirmed this product to be organopolysiloxane with the following formula. EXAMPLE 2 (Reference Example) 100 Parts organopolysiloxane (viscosity = 0.105 Pa.s, silicon-bonded hydrogen content = 0.40 weight%) with the following formula, 54.2 parts allyl glycidyl ether, and 41.6 parts toluene were placed in a 1 L four-neck flask equipped with stirrer, reflux condenser, and thermometer. The water fraction in the system was then azeotropically removed by heating while stirring. After cooling, approximately 10 drops of 2 wt% chloroplatinic acid in isopropanol were dripped into the system, which was then reheated and held at the reflux temperature of toluene for 3 hours with stirring. At this point the absence of silicon-bonded hydrogen in a sample of the reaction mixture was confirmed by infrared spectroscopic analysis. The unreacted allyl glycidyl ether and the toluene were distilled off in vacuo to afford 140 parts of a brown, transparent liquid product. This product had a viscosity of 0.520 Pa.s and an epoxy equivalent weight of 420 g/eq. The results of nuclear magnetic resonance spectroscopic analysis confirmed this product to be organopolysiloxane with the following formula EXAMPLE 3 (according to the present invention) 25 Parts organopolysiloxane (viscosity = 0.046 Pa.s, silicon-bonded hydrogen content = 0.913 weight%) with the following formula, 13 parts 1,2-epoxy-4-vinylcyclohexane, 13 parts allyltrimethoxysilane, and 10.3 parts toluene were placed in a 300 mL four-neck flask equipped with stirrer, reflux condenser, and thermometer. The water fraction in the system was then azeotropically removed by heating while stirring. After cooling, approximately 10 drops of 2 wt% chloroplatinic acid in isopropanol were dripped into the system, which was then reheated and held at the reflux temperature of toluene for 3 hours with stirring. The unreacted 1,2-epoxy-4-vinylcyclohexane and allyltrimethoxysilane and the toluene were subsequently distilled off in vacuo to afford 48.8 parts of a brown, transparent liquid product. This product had a viscosity of 1.55 Pa.s. The absorptions characteristic of the epoxy group, methoxy group, and silicon-bonded hydrogen atom were confirmed for this product by infrared absorption spectroscopic analysis. The results of nuclear magnetic resonance spectroscopic analysis confirmed this product to be organopolysiloxane with the following formula where R* is 2-(3,4-epoxycyclohexyl)ethyl. EXAMPLE 4 (Reference Example) 73.5 Parts of a 68 weight% toluene solution of organopolysiloxane (silicon-bonded hydrogen content = 0.087 weight%) with the following formula, and 7.5 parts allyl glycidyl ether were placed in a 300 mL four-neck flask equipped with stirrer, reflux condenser, and thermometer. The water fraction in the system was then azeotropically removed by heating while stirring. After cooling, approximately 10 drops of 2 wt% chloroplatinic acid in isopropanol were dripped into the system, which was then reheated and held at the reflux temperature of toluene for 1 hour with stirring. At this point the absence of silicon-bonded hydrogen in a sample of the reaction mixture was confirmed by infrared spectroscopic analysis. The unreacted allyl glycidyl ether and the toluene were distilled off in vacuo to afford 44.1 parts of a brown, transparent solid. This product had an epoxy equivalent weight of 1290 g/eq. The results of nuclear magnetic resonance spectroscopic analysis confirmed this product to be organopolysiloxane with the following formula The organopolysiloxane according to the present invention is a organopolysiloxane that is composed of monofunctional and tetrafunctional siloxane units and that contains an alkoxysilyl alkyl group and an epoxy-containing organic group. The preparative method according to the present invention is characterized by its ability to produce this organopolysiloxane.

Claims: A composition comprising an organopolysiloxane having an epoxy-containing organic group wherein said organopolysiloxane is represented by the following general formula R 1 is a non-alkenyl monovalent hydrocarbon group, each R 2 is independently selected from a hydrogen atom or a non-alkenyl monovalent hydrocarbon group, each R 3 is an epoxy-containing organic group, each R 4 is an alkoxysilylalkyl group, a is 0 or a positive number, b' , b'' and c are positive numbers, a / c has a value of 0 to less than 4, ( b' + b'' )/ c has a value of 0.05 to 4 and ( a + b' + b'' )/ c has a value of 0.2 to 4. A method for producing an organopolysiloxane having an epoxy-containing organic group comprising reacting in the presence of (A) a hydrosilylation-reaction catalyst, with (B) an SiH-containing organopolysiloxane with the general formula wherein R 1 is a non-alkenyl monovalent hydrocarbon group, d is 0 or a positive number, e and f are positive numbers, d / f has a value of 0 to 4, e / f has a value of 0.05 to 4, and ( d + e )/ f has a value of 0.2 to 4, (C) an aliphatically unsaturated epoxy-containing organic compound, and (D) an alkoxysilylalkene. The method according to claim 2 further comprising reacting in the presence of an organic solvent.

Inventors: MORITA YOSHITSUGU, MORITA, YOSHITSUGU, MORITA, YOSHITSUGU, MAIN OFFICE FOR RES., AND DEV.
Applicants: DOW CORNING TORAY SILICONE, DOW CORNING TORAY SILICONE COMPANY, LIMITED
Application year: 1992
Main classification: C08G77
IPC codes: C08G77, C08G59, C08L101, C08L83