Organic fluorosilicone alternating copolymer and its manufacturing method

Abstract: An organic silicon alternating copolymer which is resistant to chain scission by acid or alkali is disclosed, said copolymer comprising repeat units having the formula wherein R represents a monovalent hydrocarbon group having 1 to 10 carbon atoms and containing no aliphatic unsaturation, R¹ represents a fluorine atom-containing monovalent organic group having 4 to 10 carbon atoms and containing at least two groups of the formula -CF₂-, R² represents an alkylene group having 2 to 10 carbon atoms and x represents an integer having a value of 1 to 10,000.

Description: This invention concerns an organic silicon alternating copolymer and its manufacturing method. More specifically, this invention concerns a fluorine-containing organic silicon alternating copolymer characterized in that the organic silicon alternating copolymer has siloxane units and silalkylenesiloxane units bonded alternatingly in each unit. The organic silicon polymer having silalkylenesiloxane units represented by formula: wherein R' represents a monovalent hydrocarbon group, and a represents a positive integer, has a higher resistance to chain scission by acid, alkali, and other ionic substances than does a diorganopolysiloxane. Consequently, its use in special fields has been studied. For example, it has been proposed that organic silicon copolymer made of silalkylenesiloxane units and trifluoropropylmethylsiloxane units be used as the base polymer for a high-strength silicone rubber composition in JP-A 4-89866. As a manufacturing method for this organic silicon polymer having silalkylenesiloxane units, it is proposed that cleavage polymerization be performed for the cyclic silalkylenesiloxane in the prior art (Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, 739-744, April, 1971; JP-A 4-65428; JP-A 4-65429). However, for the organic silicon copolymer disclosed in JP-A 4-89866, there is no regularity in the bonds of the siloxane units, and the fluorine content is small. Consequently, it is unsuitable for applications that require good surface lubrication property, surface modification property, and oil resistance. For the manufacturing method described in Izvestiya Akademii Nauk SSSR, JP-A 4-65428 and JP-A 4-65429, it is necessary to first prepare 2,2,6,6-tetramethyl-1-oxa-2,6-disilacyclohexane, or other cyclic silalkylenesiloxane. Usually, it is difficult to prepare the cyclic silalkylenesiloxane. This is a disadvantage. Also, as reported in Izvestiya Akademii Nauk SSSR, a portion of the polysilalkylenesiloxane is depolymerized and the yield of the organic silicon polymer decreases significantly. This is also a disadvantage. EP-A 0 468 663 describes a room temperature curing composition comprising an organopolysilethylenesiloxane of the formula wherein R 1 to R 4 each represent an unsubstituted or substituted monovalent hydrocarbon group, eg a methyl group or a 6,6,6,5,5,4,4,3,3-nonafluorohexyl group. An object of the invention is to provide an organic silicon alternating copolymer with siloxane units and silalkylenesiloxane units bonded alternatingly in each unit and having a large content of fluorine atoms. A further object is the disclosure of a manufacturing method for said copolymer, said method having a high yield. This invention thus provides a type of organic silicon alternating copolymer characterized in that the main chain of the organic silicon alternating copolymer is made of repeating units represented by the following formula: wherein R represents a C 1-10 monovalent hydrocarbon group containing no aliphatic unsaturated bond; R 1 represents a C 4-10 fluorine atom-containing monovalent organic group containing two or more groups represented by -CF 2 -; R 2 represents a C 2-10 alkylene group; and x represents an integer in the range of 1-10,000. This invention also provides a manufacturing method for the organic silicon alternating copolymer, said method comprising reacting (A) an organohydrodienetrisiloxane represented by the formula: where R and R 1 are as previously defined; and (B) an unsaturated aliphatic hydrocarbon having 3-10 carbon atoms and two carbon-carbon double bonds, or an unsaturated aliphatic hydrocarbon having 2-10 carbon atoms and one carbon-carbon triple bond; in the presence of (C) a catalyst for hydrosilylation. According to our invention, an organic silicon alternating copolymer has a main chain made of repeating units represented by the following formula: where R independently represents a C 1-10 monovalent hydrocarbon group having no aliphatic unsaturated bonds. Specfic examples include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl; phenyl, tolyl, xylyl; or benzyl and phenethyl. Among them, methyl and phenyl are preferable. R 1 represents a C 4-10 fluorine atom-containing monovalent organic group containing two or more groups represented by -CF 2 -, such as the group represented by -R 3 -C m F (2m+1) , where R 3 represents a bivalent organic group, such as ethylene, propylene, butylene, pentylene; methylene oxyethylene, methylene oxypropyl, ethylene oxypropylene; phenylene ethylene, phenylene propylene, phenylene; phenylene oxyethylene, phenylene oxypropylene. Among them, ethylene and propylene are preferable. In the above formula, m represents an integer in the range of 3-8. The structure of the fluorine atom-containing monovalent organic group may be either branched, straight chain, or staight chain with a portion of a branch on the straight chain. Among these, the straight chain is preferred. R 2 represents a C 2-10 alkylene, such as ethylene, methylethylene, ethylethylene, propylethylene, butylethylene, propylene, butylene, 1-methylpropylene, pentylene, hexenylene, heptenylene, octenylene, nonenylene, decenylene. Among these, ethylene, propylene, butylene, and hexenylene are preferable. The structure of the alkylene group may be either straight chain or branched. In the formula for our alternating copolymer, x is an integer in the range of 1-10,000 and represents the degree of polymerization (DP). The molecular structure of the organic silicon alternating copolymer of this invention is straight chain or cyclic. When the structure is a straight chain, the molecular chain terminal groups are selected from hydrogen atom, hydroxy group, C 2-10 alkenyl group, and the monovalent hydrocarbon group represented by R explained above. Examples of alkenyl groups include vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, and decenyl. Examples of our organic silicon alternating copolymers include those with main chains made of the repeating units represented by the following formulas: According to our invention, the organic silicon alternating copolymer is manufactured by means of addition polymerization between organohydrodienetrisiloxane (A) and unsaturated aliphatic hydrocarbon (B) in the presence of catalyst (C). In our manufacturing method the organohydrodienetrisiloxane (A) is represented by the following formula where R and R 1 have their previously defined meanings. The following siloxanes are examples of the above mentioned organohydrodienetrisiloxane (A): and The unsaturated aliphatic hydrocarbon (B) is a component for introducing alkylene groups into our organic silicon alternating copolymer of this invention. Examples of the unsaturated aliphatic hydrocarbons having 3-10 carbon atoms and two carbon-carbon double bonds include 1,2-propadiene (known as allene), 1,3-butadiene, 2-methyl-1,3-butadiene (known as isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,4-pentadiene, 1,5-hexadiene, and 1,3-cyclohexadiene. Examples of this component having 2-10 carbon atoms and one carbon-carbon triple bond include acetylene, propyne, 1-butyne, 2-butyne, 1-pentyne, 2-pentyne, 3-methyl-1-butyne, 3,3-dimethyl-1-butyne, 1-hexyne, 2-hexyne, 1-heptyne, 1-octyne, 4-octyne, 1-nonyne, 1-decyne, and 5-decyne. In our manufacturing method, the amount of component (B) added should be appropriate to ensure that the molar ratio of component (A) to component (B) is in the range of 0.5:1.0 to 1.5:1.0. To prepare organic silicon alternating copolymer with a relatively high molecular weight, it is preferred for the molar ratio of component (A) to component (B) to be 1:1 exactly. The catalyst for the hydrosilylation reaction, component (C), is a catalyst which can promote the addition reaction between the hydrogen atoms bonded to silicon atoms in component (A) and the aliphatic unsaturated carbon bonds in component (B). It can thus promote the addition polymerization so as to manufacture our organic silicon alternating copolymer. Examples of component (C) include platinum catalysts, rhodium catalysts, palladium catalysts, organic peroxides, and the like. Among them, platinum catalysts that can significantly promote the addition polymerization are preferred. Examples of the preferable platinum catalysts include platinum black, platinum-carrying silica micron-sized powder, platinum-carrying carbon powder, chloroplatinic acid, alcohol solution of chloroplatinic acid, complex of platinum and vinyl siloxane, and complex of platinum and olefin. It is preferred that the amount of component (C) be in the range of 0.1-500 parts by weight with respect to 1 million parts by weight of the total amount of component (A) and component (B). In our method, the order in which components (A)-(C) are mixed can be selected at will. For example, the mixture of components (A) and (C) is stirred with heating and component (B) is added slowly. A mixture of component (B) and component (C) is stirred with heating, while component (A) is added slowly to the mixture. A mixture of component (A) and component (B) is stirred with heating, while component (C) is added slowly to the mixture. The mixture of components (A), (B), and (C) is heated and stirred. When component (B) is in gaseous form, it is possible to introduce this component into the mixture of components (A) and (C). When an excess amount of component (A) is added with respect to component (B), the terminals of the molecular chains of our organic silicon alternating copolymer become silicon-atom-bonded hydrogen atoms. When an excess amount of component (B) is added with respect to component (A), the terminals of the molecular chains of our organic silicon alternating copolymer become alkenyl groups. In addition, when water, alcohol, or other compound having reactive hydrogen is blended in the reaction system, the terminals of the molecular chains of our organic silicon alternating copolymer may become hydroxy groups. It is also possible to make use of an organic solvent as long as the purpose of this invention is not harmed. By using an organic solvent, it is possible to manufacture our organic silicon alternating copolymer with an even higher molecular weight. Examples of organic solvents that may be used are toluene, xylene, and other aromatic hydrocarbon solvents; hexane, heptane, octane, nonane, and other aliphatic hydrocarbon solvents; cyclohexane, cycloheptane, cyclooctane, and other alicyclic hydrocarbon solvents; trifluoromethylbenzene, 1,3-bis(trifluoromethyl)benzene, methylpentafluorobenzene, and other fluorine atom-containing aromatic hydrocarbon solvents. There is no special limitation on our manufacturing method of this invention. When the manufacturing operation is performed under ambient pressure, the reaction temperature is in the range from room temperature to the boiling point of component (A), component (B), or the boiling point of the organic solvent. When the boiling point of component (B) or the boiling point of the organic solvent is relatively low, our manufacturing operation may be performed under elevated pressure. The organic silicon alternating copolymer of this invention is in the form of a sticky liquid at room temperature. Its surface tension is low, and it has a high resistance to scission of the molecular chains by acid, alkali, and other ionic substances. For example, it can be used as the base oil for manufacturing lubricants, defoaming agents and grease, or as an additive for hydrocarbon lubricants. Besides applications as an oil, it may also be used as the base polymer for an organic-peroxide curing silicone rubber composition, addition-reaction curing silicone rubber composition, and condensation-reaction curing silicone rubber composition. Also, when the terminals of the molecular chains are silicon-bonded hydrogen atoms, it can be used as the raw material for preparing an organic silicon alternating copolymer having organic functional groups at the terminals of the molecular chains by means of an addition reaction with an alkene having organic functional groups. When the terminals of the molecular chains have alkenyl groups, it can be used as the raw material for preparing an organic silicon alternating copolymer having organic functional groups at the terminals of the molecular chains by means of the addition reaction with a hydrodienesilane having organic functional groups. When the terminals of the molecular chains have hydroxy groups, it can be used as the raw material for preparing the organic silicon alternating copolymer having organic functional groups at the terminals of the molecular chains by means of the addition reaction with halosilane or silazane having organic functional groups. Examples In the following, this invention will be explained in more detail with reference to application examples. Example 1 In a reaction container, 19.2 g of organohydrodienetrisiloxane represented by the following formula: and 20 g of 1,3-bis(trifluoromethyl)benzene were loaded, followed by adding a solution of the complex of platinum and divinyl tetramethyldisiloxane in an amount to ensure that the content of the platinum metal in the mixture was 60 ppm. While the mixture was stirred uniformly, the system was heated to 60°C. Then, while being stirred, a mixture of 2.5 g of 1,5-hexadiene and 15 g of 1,3-bis(trifluoromethyl)benzene was added dropwise at a temperature in the range of 50-100°C. After dropwise addition, the mixture was subjected to heating with reflux at 112°C for 1 h. Then, the volatile component was removed by distillation under a reduced pressure, forming a sticky liquid. Analysis of this sticky liquid by means of 13 C-nuclear magnetic resonance spectroscopy ( 13 C-NMR hereinafter), 29 Si-nuclear magnetic resonance spectroscopy ( 29 Si-NMR hereinafter), and infrared spectroscopy (IR hereinafter), verified that the obtained organic silicon alternating copolymer can be represented by the following formula: where z represents an integer of 1 or larger. Analysis of the obtained organic silicon alternating copolymer by means of gel permeation chromatogrphy (GPC hereinafter) indicated that the weight-average molecular weight was 8,000 in equivalent units to polydimethylsiloxane. The yield of the organic silicon alternating copolymer derived from the peak area was 93%. Example 2 In a reaction container, 19.2 g of organohydrodienetrisiloxane represented by the following formula: and 20 g of 1,3-bis(trifluoromethyl)benzene were loaded, followed by adding of a solution of the complex of platinum and divinyl tetramethyldisiloxane in an amount to ensure that the content of the platinum metal in the mixture was 60 ppm. While the mixture was stirred uniformly, the system was heated to 60°C. Then, while being stirred, acetylene gas was fed into this mixture for 3 h. During this process, the temperature of the mixture was raised to 70°C. It was observed that the viscosity of this mixture also increased. After feeding, the mixture was further heated at reflux for 2 h. Then, the volatile component and solvent were removed by distillation under a reduced pressure, forming a sticky liquid. Analysis of this liquid by 13 C-NMR, 29 Si-NMR, and IR verified that an organic silicon alternating copolymer was obtained that can be represented by the following formula: where z represents an integer of 1 or larger. Analysis of the obtained organic silicon alternating copolymer by means of GPC indicated that the weight-average molecular weight was 7,000 in equivalent units to polydimethylsiloxane. The yield of the organic silicon alternating copolymer derived from the peak area was 95%. Example 3 In a reaction container, 88 g of organohydrodiene-trisiloxane represented by the following formula: and 50 g of 1,3-bis(trifluoromethyl)benzene were loaded, followed by loading of a solution of the complex of platinum and divinyl tetramethyldisiloxane in an amount to ensure that the content of the platinum metal in the mixture was 100 ppm. While the mixture was stirred uniformly, the system was heated to 60°C. Then, while being stirred, a mixture of 16.4 g of 1,5-hexadiene and 15 g of 1,3-bis(trifluoromethyl)benzene was added dropwise at a temperature in the range of 50-90°C. After the addition, the mixture was heated at reflux at 112°C for 1 h. Then, the volatile component was removed by distillation under a reduced pressure, forming a sticky liquid. Analysis of this sticky liquid by 13 C-NMR, 29 Si-NMR, and IR verified that an organic silicon alternating copolymer was obtained that can be represented by the following formula: where z represents an integer of 1 or larger. Analysis of the obtained organic silicon alternating copolymer by means of GPC indicated that the weight-average molecular weight was 12,000 in equivalent units to polydimethylsiloxane. The yield of the organic silicon alternating copolymer derived from the peak area was 94%.

Claims: An organic silicon alternating copolymer comprising repeating units having the formula wherein R represents a monovalent hydrocarbon group having 1 to 10 carbon atoms and containing no aliphatic unsaturation, R 1 represents a fluorine atom-containing monovalent organic group having 4 to 10 carbon atoms and containing at least two groups of the formula -CF 2 -, R 2 represents an alkylene group having 2 to 10 carbon atoms and x represents an integer having a value of 1 to 10,000. The organic silicon alternating copolymer according to claim 1, wherein R is selected from methyl radical or phenyl radical, and R 1 has the formula -R 3 -C m F (2m+1) in which R 3 represents a bivalent organic group and m is an integer having a value of 3 to 8. The organic silicon alternating copolymer according to claim 2, wherein R 3 is selected from ethylene group or propylene group. The organic silicon alternating copolymer according to claim 3, wherein R 2 is selected from ethylene group, propylene group, butylene group and hexenylene group. The organic silicon alternating copolymer according to claim 1 having the structure The organic silicon alternating copolymer according to claim 1 having the structure The organic silicon alternating copolymer according to claim 1 having the structure The organic silicon alternating copolymer according to claim 1 having the structure The organic silicon alternating copolymer according to claim 1 having the structure The organic silicon alternating copolymer according to claim 1 having the structure The organic silicon alternating copolymer according to claim 1 having the structure A method for preparing the organic silicon alternating copolymer of claim 1, said method comprising reacting (A) an organohydrodienetrisiloxane having the formula wherein R represents a monovalent hydrocarbon group having 1 to 10 carbon atoms and containing no aliphatic unsaturation and R 1 represents a fluorine atom-containing monovalent organic group having 4 to 10 carbon atoms and containing at least two groups of the formula -CF 2 -; and (B) a compound selected from the group consisting of an unsaturated aliphatic hydrocarbon having 3-10 carbon atoms and two carbon-carbon double bonds and an unsaturated aliphatic hydrocarbon having 2-10 carbon atoms and one carbon-carbon triple bond, said reaction being carried out in the presence of (C) from 0.1 to 500 parts by weight of a hydrosilylation catalyst based on one million parts by weight of (A) plus (B), with the proviso that the amount of (B) added is sufficient to ensure a molar ratio of (A) to (B) in the range of 0.5:1.0 to 1.5:1.0.

Inventors: KOBAYASHI HIDEKI, KOBAYASHI, HIDEKI, KOBAYASHI, HIDEKI, DOW CORNING TORAY
Applicants: DOW CORNING TORAY SILICONE, DOW CORNING TORAY SILICONE COMPANY, LIMITED
Application year: 1995
Main classification: C08L83
IPC codes: C08G77, C07F7