JP3468704B2 - Method for producing carborane-containing silicon-based polymer molded article - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a carborane-containing silicon-based polymer molded article useful as a functional material having excellent heat resistance and flame retardancy. . [0002] Conventionally, silicon-based compositions having excellent heat resistance and flame retardancy have been developed. Further, attempts have been made to improve the molecular weight and mechanical strength by a method of crosslinking a polymer by a polymer reaction [(Organometallics, 15, 75 (1996)], but heat resistance and flame retardancy are not always sufficient. [0003] On the other hand, some carborane-containing silicon-based compositions are known, for example, J. Macromol.
ci. -Rev. Macromol. Chem., C17 (2), 173-208 (1979)
Report poly (dodecacarborane-siloxane). JP-T 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 organoboron polymer is obtained from the reaction of an acetylene group-containing dilithio salt with a chloro group-containing carboranesiloxane at both ends, and requires several steps to synthesize a carborane-containing silicon compound as a monomer. It was not an easy method. Further, other than the above-mentioned conventional organic boron polymers, carborane-containing silicon-based polymers are scarcely known, and development of novel carborane-containing silicon-based polymers having excellent heat resistance and flame retardancy is expected. In general, heat treatment is often performed after molding in order to improve flame retardancy. Usually, high temperature treatment is performed using an electric furnace, an infrared furnace, or the like. However, in such a heat treatment method, the decomposition and deterioration of the polymer progress, and although the flame retardancy is improved, the mechanical properties (particularly the strength) are reduced, or the flame retardancy is also reduced due to the decomposition component. Has been recognized. SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks, the present invention provides a method for efficiently crosslinking and oxidizing a polymer having a crosslinked site obtained by complexing a silicon-based polymer and a silyl-substituted carborane derivative during molding. Accordingly, it is an object of the present invention to provide a method for producing a carborane-containing silicon-based polymer molded article having improved mechanical properties, heat resistance, and flame retardancy. The process for producing a carborane-containing silicon-based polymer molded article of the present invention comprises three units represented by the general formula (1) as constituent units and has a weight average molecular weight of 5,000. A method for producing a carborane-containing silicon-based polymer molded article comprising a carborane-containing silicon-based polymer of from 5 to 5 million,
It is characterized by performing heat compression molding at a temperature of 00 to 370 ° C so that the time from the start of molding to the release of pressure is 3 to 7 minutes. In the present invention, the carborane-containing silicon-based polymer is obtained by subjecting the carborane-containing silicon-based polymer to heat compression molding, and the carborane-containing silicon-based polymer is represented by the general formula (1). Three units are constituent units. [0009] In the formula, R ¹ and R ² represent a hydrogen atom bonded to a silicon atom, an alkyl group having 1 to 20 carbon atoms or a carbon atom having 6 carbon atoms.
Represents up to 30 aryl groups, which may be the same or different. L is hydrogen Hara Komata C1-20
Represents an alkoxy group. CB _p H _q C represents carborane which is a divalent cage-like boron compound, and p and q are 3 to 16
Indicates an integer. x, y, z, and n each represent an integer of 1 or more. The positions of the two ethynylene groups with respect to the benzene ring are arbitrary. It is preferable that x, y, and z satisfy the following two equations. (Y + z) / (x + y + z) ≧ 0.2 0.1 ≦ y / (x + y + z) ≦ 0.9 The value of (y + z) / (x + y + z) is 0.2
If it is less than 1, the content of carborane is too low and sufficient heat resistance and flame retardancy cannot be obtained. Also, y / (x + y + z)
If the value is less than 0.1, the molecular weight does not increase and the heat resistance and strength become insufficient. If the value exceeds 0.9, the molecular weight becomes too large and the meltability decreases. Further, x / (x + y + z) and z / (x + y
+ Z) is preferably a value of 0.01 or more that satisfies the above expression. n is an integer determined by the values of x, y, and z and the molecular weight of the molded body, and is preferably 2
0 to 20,000. The alkyl groups represented by R ¹ and R ² include, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, 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. The aryl groups represented by R ¹ and R ² include, for example, phenyl, tolyl, xylyl, biphenyl, naphthyl, anthracenyl and the like. The alkyl group or aryl group represented by R ¹ and R ² is the same as described above. Examples of the carborane represented by CB _p H _q C include dodecacarborane, decacarborane,
Heptacarborane, hexacarborane, pentacarborane and the like can be mentioned, and the same applies to the following. The weight average molecular weight of the above-mentioned carborane-containing silicon-based polymer is limited to 5,000 or more because if it is too small, sufficient heat resistance cannot be obtained, and conversely, if it is too large, the solubility in a solvent is reduced. Is done. The method for producing the above-mentioned carborane-containing silicon-based polymer is not particularly limited. For example, a double bond may be added to a terminal of a side chain comprising a combination of a hydrocarbon group represented by the general formula (2) and (3). It is obtained by reacting a silicon compound having the compound with a silyl-substituted carborane derivative represented by the general formula (4) using a catalyst. Embedded image Embedded image Embedded image In the formula, R ¹ and R ² are a hydrogen atom bonded to a silicon atom, an alkyl group having 1 to 20 carbon atoms, and a carbon atom having 6 to 3 carbon atoms.
Represents an aryl group of 0, and may be the same or different. The positions of the two ethynylene groups with respect to the benzene ring are arbitrary. CBpHqC represents carborane which is a divalent cage-like boron compound, and p,
q shows the integer of 3-16. The carborane-containing silicon-based polymer is subjected to heat compression molding to obtain a carborane-containing silicon-based polymer. As a molding condition in the heat compression molding, a method in which a heating temperature is 300 to 370 ° C. and a time from the start of molding to the release of pressure is 3 to 7 minutes is adopted. When the heating temperature is lower than 300 ° C., the effect of improving the flame retardancy is not observed in the molded article. When the heating temperature is higher than 370 ° C., a thermal decomposition reaction occurs, so that the flame retardancy is reduced and embrittlement occurs. become. The above temperature range is selected in order to achieve both flame retardancy and mechanical strength. If the time from the start of the molding to the release of the pressure is shorter than 3 minutes, the carborane-containing silicon-based polymer is not sufficiently melted, the mechanical strength is reduced, and the effect of improving the flame retardancy is not seen. Further, when the heat treatment time exceeds 7 minutes, thermal decomposition occurs, so that flame retardancy is reduced and embrittlement occurs. If the product is cooled rapidly after the above-mentioned compression molding, the molded product may be damaged by distortion.
It is preferable to cool slowly at a rate of about ° C / hour. Embodiments of the present invention will be described below together with comparative examples. Example 1 20.5 g (80 mmol) of poly ( p- diethynylbenzene / phenylvinylsilylene) was placed in a 1-liter four-necked flask equipped with a reflux tube purged with argon, and toluene was added.
Dissolved in 00 ml. The reaction mixture was heated to 50 ° C., the catalyst _{(H 2 PtCl 6 · 6H 2} O) 10.3mg
3.2 ml of an isopropanol solution (0.02 mmol) was added and stirred for 5 minutes, and then 20.87 g of 1,7-bis (dimethylsilyl) dodecacarborane (8.
(80 mmol) of a toluene solution of 0 mmol) was dropped, and the temperature of the oil bath was raised to 120 ° C., and the mixture was heated and refluxed for 8 hours. Next, the reaction solution was distilled off under reduced pressure, and then poured into 500 ml of methanol. The precipitate is filtered off,
Yellow-white powdery polymerization product 2 represented by the following formula (6)
8.53 g were obtained. Embedded image The above polymerization product is represented by the formula (6)
Is a mixture of OCH ₃ or H, and x / (x + y + z)
Was 0.46. The weight average molecular weight in terms of polystyrene was 25,000. The obtained polymerization product was subjected to heat compression molding. First, the polymerization product was preheated at 350 ° C. without pressurizing for 4 minutes, degassed 10 times in 30 seconds, and then kept in a pressurized state for 30 seconds. Thereafter, the pressure was released to stop heating, and the mixture was cooled at a cooling rate of 50 ° C./hour to obtain a carborane-containing silicon-based polymer molded article. Example 2 The polymerization product obtained in Example 1 was preheated at 320 ° C. without pressurizing for 6 minutes, degassed 10 times in 30 seconds, and then pressurized. Hold for 30 seconds. After pressurizing for 30 seconds, the pressure was released to stop heating, and the mixture was cooled at a cooling rate of 50 ° C./hour to obtain a carborane-containing silicon-based polymer molded article. Example 3 The polymerization product obtained in Example 1 was first preheated at 360 ° C. for 2 minutes without applying pressure.
After degassing 10 times in 30 seconds, 30
Hold for 2 seconds. After pressurizing for 30 seconds, the pressure was released to stop heating, and the mixture was cooled at a cooling rate of 50 ° C./hour to obtain a carborane-containing silicon-based polymer molded article. Comparative Example 1 The polymerization product obtained in Example 1 was first preheated at 250 ° C. for 4 minutes without pressurizing.
After degassing 10 times in 30 seconds, 30
Hold for 2 seconds. After pressurizing for 30 seconds, the pressure was released to stop heating, and the mixture was cooled at a cooling rate of 50 ° C./hour to obtain a carborane-containing silicon-based polymer molded article. Comparative Example 2 The polymerization product obtained in Example 1 was first preheated at 350 ° C. for 10 minutes without pressurization, degassed 10 times for 30 seconds, and then pressurized. The state was maintained for 30 seconds. After pressurizing for 30 seconds, the pressure was released to stop heating, and cooling was performed at a cooling rate of 50 ° C./hour. The obtained molded body was broken into small pieces, and the following physical properties could not be evaluated. Comparative Example 3 The polymerization product obtained in Example 1 was first preheated at 350 ° C. for 1 minute without pressurizing.
After degassing 10 times in 30 seconds, 30
Hold for 2 seconds. The polymerization product did not melt sufficiently and a molded product was not obtained. Comparative Example 4 The polymerization product obtained in Example 1 was first preheated at 380 ° C. for 4 minutes without pressurizing.
After degassing 10 times in 30 seconds, 30
Hold for 2 seconds. After pressurizing for 30 seconds, the pressure was released to stop heating, and the mixture was cooled at a cooling rate of 50 ° C./hour to obtain a carborane-containing silicon-based polymer molded article. The carborane-containing silicon-based polymer molded articles obtained in the above Examples and Comparative Examples were evaluated for the physical properties of the following items, and the results are shown in Table 1. (1) Bending test A bending test was performed in accordance with JIS K 7203, and a bending elastic modulus and a bending strength were measured. (2) Oxygen index The oxygen index was measured according to JIS K 7201. [Table 1] In the examples, the oxygen index was improved while maintaining the mechanical strength. As can be seen from the comparative examples, when the molding temperature decreases, the oxygen index decreases (Comparative Example 1), and when the molding temperature increases, the polymerization product deteriorates, and both the oxygen index and the bending strength decrease (Comparative Example 4). In addition, if the molding time is long, the polymerization product is deteriorated, so that a molded article cannot be obtained (Comparative Example 2). Example 3). The method for producing the carborane-containing silicon-based polymer molded article of the present invention is as described above. The obtained molded article is excellent in heat resistance and flame retardancy, and is used for space and aviation materials. ,
It is suitably used for building materials and the like.

Continuation of the front page (56) References JP-A-50-44299 (JP, A) JP-A-5-262878 (JP, A) JP-A-6-49430 (JP, A) JP-A-6-172712 (JP, A) JP-A-11-240957 (JP, A) JP-A-11-240956 (JP, A) JP-A-11-1561 (JP, A) JP-A-11-269270 (JP, A) JP2000 -72878 (JP, A) JP44-2240 (JP, B1) JP8-505649 (JP, A) JP8-507795 (JP, A) JP10-509750 (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 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claim 1] Carborane comprising a carborane-containing silicon-based polymer having three units represented by the general formula (1) as constituent units and having a weight average molecular weight of 5,000 to 5,000,000. Press-molding the carborane-containing silicon-based polymer at a temperature of 300 to 370 ° C. so that the time from the start of molding to the release of pressure is 3 to 7 minutes. A method for producing a carborane-containing silicon-based polymer molded article, comprising: Embedded image (Wherein, R ¹ and R ² represent a hydrogen atom bonded to a silicon 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. .L is hydrogen Hara Komata represents an alkoxy group having 1 to 20 carbon atoms. the position relative to the benzene ring of the two ethynylene group is optional .CB _p H _q C is a divalent cage-like boron Represents carborane which is a compound, p and q each represent an integer of 3 to 16. x, y, z, and n each represent an integer of 1 or more.)