JP3468716B2 - Method for producing cured silicon-containing resin containing carborane - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a novel cured carborane-containing silicon resin useful as a material having excellent heat resistance and flame retardancy. [0002] In recent years, attempts have been made to develop silicon-based polymers having extremely high heat resistance, flame retardancy and mechanical strength intended for use in the field of automotive electrical components and aerospace materials. I have. For example, there is an example in which the molecular weight and mechanical strength are improved by a method of crosslinking a polymer by a polymer reaction {Organometallics, 15, 75 (1996)}. [0003] On the other hand, some carborane-containing silicon-based polymers are known, for example, J. Macromol.
i.-Rev.Macromol.Chem., C17 (2), 173-208 (1979)
It has been reported for poly (dodecacarborane-siloxane). [0004] Japanese Patent Publication No. 8-505649 discloses an organoboron polymer, and reports that the introduction of carborane improves the thermal stability of a siloxane polymer. However, the above-mentioned organic boron polymer is obtained from the reaction of an acetylene group-containing dilithio salt and a chloro group-containing carborane siloxane at both ends, and requires several steps to synthesize a carborane-containing silicon compound as a monomer. Absent. [0005] In addition to the above-mentioned organoboron polymer,
Almost no carborane-containing silicon-based polymer is known, and development of a novel carborane-containing silicon-based polymer having both heat resistance, flame retardancy and mechanical strength is expected. As described above, the carborane-containing silicon-based polymer is excellent in heat resistance and flame retardancy, so that it is used as an electrical insulator, a paint, an adhesive for a laminated product, and the like in automobile electric components, aerospace materials, building materials, and the like. Its application has been widely studied. In recent years, as applications have expanded, demands for further flame retardancy have increased, but less consideration has been given to flame retardancy than other resin compositions. For example, among silicon-based polymers, silicone rubber has an oxygen index of 25 to 27 indicating its flame retardancy,
It is not always enough depending on the application ("Fire retardation of polymer" by Hitoshi Nishizawa, Taiseisha Publishing). [0008] Among the silicon-based polymers, those that emit a small amount of smoke and a small amount of toxic gas during combustion can be said to be advantageous in terms of safety, but are usually flame retardants for such silicon-based polymers. When an organic halide, antimony trioxide, or the like is added, there is a problem that the physical properties are greatly reduced and it is not possible to use the material. SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems by treating a polymer obtained by complexing a silicon-based polymer and a silyl-substituted carborane derivative at a high temperature. By forming a flame-retardant boron oxide by oxidizing carborane contained in a polymer and forming a ceramic of a silicon-based polymer, mechanical strength, a method for producing a cured carborane-containing silicon-based resin having further improved flame retardancy. The task is to provide. [0010] The method for producing a cured product of a silicon-containing carborane-containing resin according to the present invention is as follows.
It comprises units represented by the following general formulas (1), (2) and (3), and has a weight average molecular weight of 1,000 to
The 5 million carborane-containing silicon polymer 100
Characterized by a heat treatment at 0 ° C. to 2000 ° C.. Embedded image Embedded image Embedded image (Wherein, R ¹ and R ² represent a hydrogen atom bonded to a silicon-based atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 30 carbon atoms, and may be the same or different. .R ³ may or may not show an alkylene group or an arylene group having 6 to 30 carbon atoms having 1 to 20 carbon atoms. when there is no R ³ is a vinyl group is bonded directly to a silicon atom. Further, Z is an alkoxy group of hydrogen or carbon number of 1 to 20. Note that the position relative to the benzene ring of the two ethynylene group is optional, carboranes C BPH
a divalent cage boron compound represented by qC, p and q
Represents a positive integer of 3 to 16. Examples of the alkyl group represented by R ¹ and R ² include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group and a decyl group. , Undecyl group, dodecyl group,
Examples include a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an eicosyl group, and the like. Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, a biphenyl group, a naphthyl group, and anthracenyl. Examples of the alkylene group represented by R ³ include a methylene group, an ethylene group, a propylene group,
Butylene group, pentylene group, hexylene group, heptylene group, octylene group, nonylene group, decylene group, undecylene group, dodecylene group, tridecylene group, tetradecylene group, pentadecylene group, hexadecylene group, heptadecylene group, octadecylene group, nonadecylene group, eicosylene group And the like. The arylene group represented by R ³ includes, for example, a phenylene group, a trin group, a xylylene group, a biphenylene group, a naphthalenylene group, and an anthracenylene group. The alkyl group or aryl group represented by R ¹ and R ² is the same as above, and the alkylene group or arylene group represented by R ³ is also the same as above. The carborane is, for example,
Dodeca carborane (CB ₁₀ H ₁₀ C), Dekakaruboran,
Heptacarborane, hexacarborane, pentacarborane and the like can be mentioned. If the amount of the structural unit represented by the general formula (1) is too small or too large, the moldability is reduced.
ol% is preferred. In addition, general formula (2) and general formula (3)
When the amount of the carborane-containing unit represented by the formula is too small, sufficient heat resistance cannot be obtained, and when the amount is too large, the moldability decreases. The ratio between the general formulas (2) and (3) is arbitrary, but if the ratio of the formula (2) is small, sufficient moldability cannot be obtained, so that 0.2 <(2) / [( 2) + (3)] <
It is preferably 0.9. If the weight-average molecular weight of the carborane-containing silicon-based polymer obtained in the present invention is too small, sufficient heat resistance cannot be obtained, so that it is limited to 1,000 or more. Limited to 10,000 or less. The method for producing the carborane-containing silicon-based polymer used in the present invention is not particularly limited, but the side chain of the combination of the hydrocarbon group represented by the following general formula (4) and the following general formula (5) is used. It is characterized by reacting a silicon-based polymer having a double bond at a terminal with a silyl-substituted carborane derivative represented by the following general formula (6) using a catalyst. Embedded image Embedded image Embedded image (Wherein, R ¹ and R ² represent a hydrogen atom bonded to a silicon atom,
Represents an alkyl group having 1 to 20 carbon atoms and an aryl group having 6 to 30 carbon atoms, which may be the same or different. R ³ does not need to represent an alkylene group having 1 to 20 carbon atoms or an arylene group having 6 to 30 carbon atoms. In addition,
In the absence of R ³ , a vinyl group is directly bonded to the silicon atom. The positions of the two ethynylene groups with respect to the benzene ring are arbitrary, and carborane is a divalent cage-like boron compound represented by CBpHqC, where p and q are 3 to 16
Represents a positive integer. The hydrocarbon group represented by the general formula (4) includes, for example, 1,3-diethynylbenzene, 1,4-diethynylbenzene and the like. Examples of the double bond group-containing silylene group represented by the general formula (5) include methylvinylsilylene, phenylvinylsilylene, methylallylsilylene, and phenylallylsilylene. The bissilylcarborane derivative represented by the general formula (6) includes, for example, bis (dimethylsilyl)
Carborane, bis (diphenylsilyl) carborane, bis (methylphenylsilyl) carborane and the like. The catalyst used in the above reaction is chloroplatinic acid,
(Bis (divinyltetramethyldisiloxane) platinum, hexarhodium hexadecacarbonyl, etc. The solvent used in the above reaction may be either polar or non-polar, but is preferably an aprotic solvent such as toluene or tetrahydrofuran. The above reaction is carried out at a temperature between room temperature and the boiling point of the solvent, and the reaction can be carried out either in air or under an inert gas atmosphere, preferably under an argon gas or nitrogen gas atmosphere. If the reaction time of the above reaction is too short, the introduction reaction of carborane does not proceed sufficiently and the heat resistance does not improve. Conversely, if the reaction time is too long, the crosslinking reaction proceeds and the solvent does not dissolve in the solvent. It is preferable to use the method for purifying the silicon-based polymer after completion of the reaction. Examples of the method include a reprecipitation method or fractionation by gel permeation chromatography (GPC), etc. In the method for producing a cured product of a carborane-containing silicon-based resin of the present invention, the above-mentioned carborane-containing silicon-based polymer is used. heat that handles. [0029] the heat treatment temperature becomes oxidation and curing reaction becomes insufficient flame retardancy does not proceed sufficiently low, so becomes higher when the silicon compound is degraded strength is reduced, 10
It needs to be 00 to 2000 ° C. The heat treatment time is preferably 1 minute to 10 hours, because if the heat treatment time is short, the oxidation and curing reactions do not proceed sufficiently, and if the heat treatment time is long, deterioration occurs. Further, the heat treatment proceeds in the air or in an atmosphere of an inert gas such as nitrogen or argon. However, in order to more effectively carry out the oxidation reaction of carborane, the heat treatment is preferably performed in an air atmosphere. The cured product of the carborane-containing silicon resin of the present invention
The production method is a compound of a silicon-based polymer and a silyl-substituted carborane derivative, and a carborane-containing silicon-based polymer having a specific weight-average molecular weight is heat-treated at a specific temperature, so that the silicon-containing polymer is contained in the polymer. Carborane- containing silicon-based resin that exhibits excellent heat resistance and flame retardancy while having high mechanical strength by forming flame-retardant boron oxide by carborane oxidation and converting the silicon-based polymer to ceramics.
A fat cured product is obtained . The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited to only these Examples. Example 1 20.51 g (80 mmol) of poly (m-diethynylbenzene / phenylvinylsilylene) was placed in a 1-liter four-necked flask equipped with a reflux tube purged with argon.
It was dissolved in 450 ml of toluene. The temperature of the reaction solution was raised to 50 ° C., and the catalyst (bis (divinyltetramethyldisiloxane))
A toluene solution of platinum [Pt (CH ₂ = CHSi (CH ₃ ) ₂ OSi (CH ₃ ) ₂ CH = CH ₂ ) ₂ ] is added to the poly (m-diethynylbenzene / phenylvinylsilylene) in an amount of 0.5 mol based on the vinyl group. % And stirred for 10 minutes. 1,7-bis After dropwise a toluene solution 50ml of (di methylsilyl) dodeca carborane 10.43 g (40 mmol), the temperature of the oil bath 1
The temperature was raised to 25 ° C. and the mixture was refluxed for 10 hours. After the reaction solution was distilled off under reduced pressure, it was poured into 1.7 l of isopropanol. The precipitate was separated by filtration to obtain 25.54 g of a yellowish white powder. The weight average molecular weight of this polymer was 62,20 in terms of polystyrene.
It was 0. FIG. 1 shows the ¹ H-NMR spectrum (measured by DRX300 manufactured by Bruker) of the obtained product. FIG.
And a peak of a proton based on carborane is observed from 0.7 to 4 ppm. In addition, 0.07 to 0.6 ppm
The peak of a proton of a methyl group and a methylene group bonded to a silicon atom was confirmed, and the peak of a proton of a phenyl group was confirmed at 7 to 8 ppm. It was confirmed that the product obtained from this was a carborane-containing silicon-based polymer represented by the following general formula (7). Embedded image The carborane-containing silicon-based polymer obtained by the above polymerization reaction was subjected to heat compression molding at 250 ° C. to produce a molded article. This molded body is heated in air in an electric furnace at 200 ° C./hour.
The temperature was raised to 1000 ° C. at a heating rate of 1 ° C., and after the temperature reached 1000 ° C., heat treatment was performed for 1 hour to produce a cured silicon-containing resin containing carborane. (Comparative Example 1) A molded article obtained by heating and compressing the carborane-containing silicon-based polymer synthesized in Example 1 at 250 ° C was used as it was. The flexural modulus and oxygen index of the cured product of the carborane-containing silicon-based resin obtained in Example 1 and the molded product of the carborane-containing silicon-based polymer of Comparative Example 1 were as follows:
Was results measured and shown in Table 1 by law. (1) Bending test is performed according to JIS K 7203
The elastic modulus was measured. (2) Oxygen index The oxygen index was measured in accordance with JIS K 7201. [Table 1] As is clear from Table 1, the cured product of the silicon-containing carborane-containing resin of Example 1 has improved flexural modulus and oxygen index as compared with the silicon-containing polymer of carborane of Comparative Example 1. . [0043] As described above, according to the present invention, the present invention thus obtained, et al
The cured carborane-containing silicon-based resin has excellent heat resistance and flame retardancy while having high mechanical strength, and thus is suitably used for space / aviation materials, building materials, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a ¹ H-NMR spectrum of a carborane-containing silicon-based polymer used in Example 1.

Continuation of the front page (56) References JP-A-11-1561 (JP, A) JP-A-11-240957 (JP, A) JP-A-50-44299 (JP, A) JP-A-5-262878 (JP) JP-A-6-49430 (JP, A) JP-A-6-172712 (JP, A) JP-A-11-240956 (JP, A) JP-A-11-269270 (JP, A) JP2000 -1919397 (JP, A) JP 44-2240 (JP, B1) JP 8-505649 (JP, A) JP 8-507795 (JP, A) JP 10-509750 (JP, A) U.S. Pat. No. 3,388,090 (US, A) U.S. Pat. No. 3,388,091 (US, A) U.S. Pat. No. 5,552,505 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 77/00-77/62 C08G 79/00-79/14 C04B 35/56-35/58 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claim 1] It is composed of units represented by the following general formulas (1), (2) and (3), and has a weight average molecular weight of 1,000 to 5,000,000. production side of carborane-containing silicon-based resin cured product characterized by heat-treating the carborane-containing silicon-based polymer at 1000 ° C. to 2000 ° C.
Law . Embedded image Embedded image Embedded image (Wherein, R ¹ and R ² represent a hydrogen atom bonded to a silicon atom,
Represents an alkyl group having 1 to 20 carbon atoms and an aryl group having 6 to 30 carbon atoms, which may be the same or different. R ³ does not need to represent an alkylene group having 1 to 20 carbon atoms or an arylene group having 6 to 30 carbon atoms. In addition,
In the absence of R ³ , a vinyl group is directly bonded to the silicon atom. Further, Z is an alkoxy group of hydrogen or a C 1-20. The position of the two ethynylene groups with respect to the benzene ring is arbitrary, and carborane is represented by CBpHqC
Wherein p and q are 3
Represents a positive integer of １６16. )