JPH11106513A - Silicon-base polymer containing carborane, its production and cured silicon-base resin containing carborane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new carborane-containing silicon-base polymer which has constituent units with a specified constitution in the structure, has a specified weight-average molecular weight, and is excellent in heat resistance and flame retardancy. SOLUTION: The constituent units have a constitution represented by formula I [wherein R<1> is H, a 1-20C alkyl, or a 6-30C aryl; CBp Hp 'C is a carborane comprising a divalent cage boron compound; p and p' are each 3 to 16; n and m are each an integer; U is repeating units of a silicon-base polymer comprising constituents of formula II and formula III (wherein R<1> to R<5> are each II, a 1-20C alkyl, or a 6-30C aryl); and V is repeating units of a silicon-base polymer comprising constituents of formula III and formula IV (wherein the symbols are as defined above)]. The weight-average molecular weight of this polymer is at least 500. This polymer is produced by reacting a silylated carborane derivative with the terminal triple bonds of the principal chain of a silicon-base polymer. A catalyst comprising, e.g. chloroplatinic acid is used. The molar ratio of the silicon-base polymer to the carborane derivative is preferably 1:(0.01 to 2).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel carborane-containing silicon-based polymer useful as a functional material having excellent heat resistance, a method for producing the same, and a carborane-containing silicon-based resin cured product.

[0002]

2. Description of the Related Art Conventionally, silicon polymers having excellent heat resistance and flame retardancy have been developed. Further, attempts have been made to increase the molecular weight and improve the mechanical strength by a method of crosslinking a polymer by a polymer reaction [Organometallics, 15, 75 (1996)].
However, heat resistance and flame retardancy were not always sufficient. On the other hand, some carborane-containing silicon-based polymers are known, for example, J. Macromol. Sci. -Re
v. Macromol. Chem., C17 (2), 173-208 (1979)
It has been reported for poly (dodecacarborane-siloxane).

Further, Japanese Patent Publication No. Hei 8-505649 discloses an organic boron polymer, and reports that the thermal stability of a siloxane polymer is improved by introducing carborane. However, the above-mentioned organoboron polymer is obtained from the reaction between 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-based compound from a monomer. It was not the way.

[0004] In addition to the above-mentioned conventional organic boron polymers, carborane-containing silicon-based polymers are scarcely known, and development of new carborane-containing silicon-based polymers having excellent heat resistance is expected.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel carborane-containing silicon-based polymer having excellent heat resistance and flame retardancy, a method for producing the same, and a cured product of the carborane-containing silicon-based resin. .

[0006]

In the present invention, an attempt was made to form a complex between a silicon-based polymer having a reactive ethynyl group at the main chain terminal and a silyl-substituted carborane derivative. The reaction between the ethynyl group and the silyl group is very efficient, carborane can be easily introduced into the polymer, and further improvement in the heat resistance and flame retardancy of the polymer can be expected.

The carborane-containing silicon-based polymer according to the first aspect of the present invention (hereinafter referred to as the first aspect of the present invention) has a general formula (1)
Having a structural unit represented by the formula in the structure, and having a weight average molecular weight of 500 or more.

The method for producing a carborane-containing silicon-based polymer of the invention according to claim 2 (hereinafter referred to as the present invention 2) is a method for producing a carborane-containing silicon-based polymer of the present invention, comprising the general formula (5) ) Is reacted with the terminal triple bond of the main chain of the silicon-based polymer represented by the general formulas (6), (7) and (8).

The carborane-containing silicon-based resin cured product according to the third aspect of the invention (hereinafter referred to as the third aspect of the invention) is the first aspect of the invention.
By cross-linking the carborane-containing silicon-based polymer.

Hereinafter, the present invention will be described in detail. The carborane-containing silicon-based polymer of the first invention has a carborane-containing structural unit represented by the general formula (1) in the polymer.

[0011]

Embedded image

In the formula (1), R ¹ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 30 carbon atoms bonded to a silicon atom. You may. CBpHp'C represents carborane which is a divalent cage-like boron compound, and p and p 'are 3
Represents an integer of ~ 16, and n and m represent integers. Equation (1)
In the formula, U represents a repetition of a silicon-based polymer having the following formulas (2) and (3) as components, and V represents a silicon-based polymer having the following formulas (3) and (4) as components. Represents repetition)

Embedded image

Embedded image

Embedded image In the formulas (2), (3), and (4), R ^{1 to} R ⁵ represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 30 carbon atoms. It may be different. The positions of the ethynylene group and R ^{2 to} R ⁵ with respect to the benzene ring are arbitrary.

When the number of carbon atoms in the hydrocarbon group represented by R ^{1 to} R ⁵ increases, the bond is easily broken when the number of aliphatic groups increases, and the heat resistance decreases. Since the solubility is reduced, each of the above ranges is limited.

The alkyl group represented by R ^{1 to} R ⁵ includes, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, Undecyl group, dodecyl group,
Examples include tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl and the like.

The aryl group represented by R ^{1 to} R ⁵ includes, for example, a phenyl group, a tolyl group, a xylyl group, a biphenyl group and a naphthyl group.

The carborane represented by CBpHp'C includes, for example, dodecacarborane, decacarborane, heptacarborane, hexacarborane, pentacarborane and the like.

The weight-average molecular weight of the silicon-based polymer of the present invention 1 is limited to 500 or more because sufficient heat resistance cannot be obtained when it is too small. The upper limit of the weight average molecular weight is not particularly limited, but if it is too large, the solubility is reduced and it becomes difficult to obtain a molded product.

Next, the present invention 2 will be described. The method for producing a carborane-containing silicon-based polymer according to the second aspect of the present invention is a method for producing a carborane-containing silicon-based polymer according to the first aspect of the present invention, wherein the silyl-substituted carborane derivative represented by the general formula (5) and the general formula ( 6), characterized by reacting with the terminal triple bond of the main chain of the silicon polymer represented by (7) and (8).

[0019]

Embedded image

[0020]

Embedded image

[0021]

Embedded image

[0022]

Embedded image

In the formula (5), R ¹ is 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. CBpHp'C represents carborane which is a bivalent cage-like boron compound, and p and p 'are 3 to
Represents an integer of 16. In the formulas (6), (7) and (8), X represents a structural unit represented by the following general formula (9), Y represents a structural unit represented by the following general formula (10), and m represents an integer. .

[0024]

Embedded image

[0025]

Embedded image

In the formula (9), R ^{2 to} R ⁵ represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 30 carbon atoms, which may be the same or different. . The positions of the ethynylene group and R ^{2 to} R ⁵ with respect to the benzene ring are arbitrary. In the formula (10), R ⁶ represents 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, which may be the same or different.

When the number of carbon atoms of the hydrocarbon group represented by R ^{1 to} R ⁶ is greater in the case of an aliphatic group, the bond is easily broken and the heat resistance is reduced. Because it decreases, it is limited to the above range.

Examples of the alkyl group represented by R ^{1 to} R ⁶ include those similar to the alkyl group represented by R ^{1 to} R ⁵ in the ^first embodiment. The aryl group represented by R ¹ to R ^6, in the present invention 1 R ¹ ~
The same as the aryl group represented by R ⁵ can be mentioned.

The carborane represented by CBpHp'C includes the same components as those of the first invention.

As the silyl-substituted carborane derivative represented by the above formula (5), as a disubstitute, for example, m-bis (dimethylsilyl) carborane, m-bis (diethylsilyl) carborane, m-bis (dipropyl) (Silyl) carborane, m-bis (dibutylsilyl) carborane, m
-Bis (dipentylsilyl) carborane, m-bis (dihexylsilyl) carborane, m-bis (diphenylsilyl) carborane, m-bis (ditolylsilyl) carborane, m-bis (dixylsilyl) carborane, m-
Bis (dibiphenylsilyl) carborane, m-bis (dinaphthylsilyl) carborane, m-bis (dianthracenylsilyl) carborane, m-bis (methylphenylsilyl) carborane, m-bis (ethylphenylsilyl)
Carborane, m-bis (propylphenylsilyl) carborane, m-bis (butylphenylsilyl) carborane, m-bis (pentylphenylsilyl) carborane,
m-bis (hexylphenylsilyl) carborane and their o- and p-isomers.

The structural unit of the silicon-based polymer represented by Y is, for example, dimethyldichlorosilane, diphenyldichlorosilane, dimethoxydichlorosilane, dimethoxydiphenylsilane, bis (dimethylamino) dimethylsilane, bis (dimethylamino) Diphenylsilane, bis (1-pyridinyl) dimethylsilane, bis (1
-Pyridinyl) diphenylsilane, bis (1,1-tetramethylene-3-phenylureido) dimethylsilane,
Examples include, but are not limited to, bis (1,1-tetramethylene-3-phenylureido) diphenylsilane.

Examples of the catalyst used in the reaction in the production method of the present invention 2 include, but are not limited to, chloroplatinic acid and hexarhodium hexadecacarbonyl. If the amount of the catalyst used is too small, the reaction does not proceed sufficiently, and if it is too large, it tends to remain in the polymer after synthesis and the heat resistance is reduced.
0.001 to 20 mol% is preferable with respect to the structural unit (Y) of the silicon-based polymer represented by (7) and (8),
More preferably, it is 0.01 to 10 mol%.

The molar ratio of the silicon-based polymer to the silyl-substituted carborane derivative used in the above reaction is such that when the amount of carborane introduced is small, the heat resistance and flame retardancy of the obtained polymer are not significantly improved. Coalescence: The silyl-substituted carborane derivative is preferably 1: 0.01 to 2, more preferably 1: 0.1 to 1.5.

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 amount of the solvent used is 0.01 to 5 in terms of the concentration of the structural unit of the silicon-based polymer.
0 mol / L is preferable, and more preferably 0.05 to 5
mol / L.

The above reaction is preferably carried out between room temperature and the boiling point of the solvent. This reaction can be carried out either in air or under an inert gas atmosphere, but preferably under an argon gas or nitrogen gas atmosphere.

If the reaction time of the above reaction is short, the introduction reaction of carborane does not proceed sufficiently, and the heat resistance of the obtained polymer does not improve. Conversely, if the reaction time is long, a side reaction such as cross-linking proceeds, and It will not melt, making it difficult to handle,
Since heat resistance falls, 1 to 96 hours are preferable. After completion of the reaction, the silicon-based polymer may be purified by a reprecipitation method or gel permeation chromatography (GP).
C) and the like.

The cured product of the carborane-containing silicon-based resin of the present invention 3 is obtained by crosslinking the carborane-containing silicon-based polymer of the present invention 1. A material having higher heat resistance is obtained by subjecting the acetylene group of the carborane-containing silicon-based polymer to a cross-linking reaction.

The method for crosslinking the carborane-containing silicon-based polymer is not particularly limited, and heat, light or an electron beam can be used. The heating temperature in the case of performing thermal crosslinking is preferably 250 to 600 ° C., more preferably 250 to 600 ° C., because the crosslinking reaction does not sufficiently occur and the curing becomes insufficient and the acetylene group-containing silicon-based polymer deteriorates before crosslinking. Is 300 to 500 ° C.

The thermal crosslinking reaction proceeds in an atmosphere of air or an inert gas or under reduced pressure. When the reaction time of the thermal crosslinking reaction is short, the crosslinking reaction does not sufficiently occur and curing is insufficient, and when the reaction time is long, a deterioration reaction occurs.
0 hours is preferable, and more preferably 30 minutes to 5 hours.

In the case of the photocrosslinking, irradiation with actinic rays is used, and examples of the actinic rays include ultraviolet rays and electron beams. When irradiating with ultraviolet rays, when the irradiation amount is small, the crosslinking reaction does not proceed sufficiently and curing is insufficient, and when the irradiation amount is large, a decomposition reaction occurs. Therefore, the integrated exposure amount at 365 nm is preferably 50 to 5000 mJ / cm ² .

The light source used for irradiating ultraviolet rays includes
For example, a high-pressure mercury lamp, a halogen lamp, a xenon lamp, a nitrogen laser, a He-Cd laser, an Ar laser, or the like is used.

When irradiating the above-mentioned electron beam, if the irradiation amount is small, the crosslinking reaction does not proceed sufficiently and curing is insufficient, and if the irradiation amount is large, a decomposition reaction occurs.
0 Mrad is preferred.

The photocrosslinking reaction proceeds regardless of the atmosphere in an air or an inert gas or under reduced pressure.

[0044]

Embodiments of the present invention will be described below.

Example 1 Argon-substituted reflux tube 1
Ethynylated poly in a 00 ml two-necked flask
(1,4-diethynylbenzene / methylphenylsila
3.25 g (2.0 mmol) of toluene
After dissolving in 0 ml, the temperature was raised to 55 ° C. and the catalyst (H _TwoPtC
l₆・ 6H_TwoO) 0.012 g (0.02 mmol)
Add 1 ml of isopropanol solution and stir for 10 minutes.
Was. Then, 1,7-bis (dimethylsilyl) dodecaca
A solution of 0.53 g (2.0 mmol) of ruborane in toluene
After dropping 15ml, raise the temperature of the oil bath to 120 ° C
And heated to reflux for 10 hours. Next, the reaction solution is distilled off under reduced pressure.
After that, it was charged into 500 ml of methanol. The obtained sunk
The precipitate was filtered off to obtain 3.2 g of a yellow-white powder (polymer).
Was.

The ¹ H-NMR spectrum ("DR" manufactured by Bruker) measured on the yellowish white powder obtained above
X300 ") is shown in FIG. 1, and the IR spectrum (measured by Biorad" FTS135 System ") is shown in FIG. In FIG. 1, a peak of a proton based on carborane is observed from 0.7 to 4 ppm. Also,
A peak of a proton of a methyl group and a methylene group bonded to a silicon atom was confirmed at 0.09 to 0.6 ppm, and a peak of a proton of a phenyl group was confirmed at 7 to 8 ppm. Further, in FIG. 2, absorption due to carborane was observed at 2594 cm ^−1, and it was confirmed from these facts that the polymer obtained in Example 1 was a silicon-based polymer into which carborane was introduced. The weight average molecular weight of this polymer was 10,300 in terms of polystyrene. The silicon-based polymer was heated at 330 ° C. for 2 hours to cause a cross-linking reaction, and then cooled to room temperature to obtain a molded product made of a cured silicon-based resin.

FIG. 3 shows the IR spectrum of the molded article of Example 1 above. As can be seen from FIG.
Absorption based on internal acetylene group of 160 cm ^-1 and 328
It can be seen that the absorption based on the terminal ethynyl group near 0 cm ^-1 is reduced. Further, the polymer that was soluble in the solvent is insolubilized after thermal crosslinking. These facts suggest that the internal acetylene group and the terminal ethynyl group undergo a crosslinking reaction to form a network structure.

(Comparative Example 1) 1 with a reflux tube replaced with argon
In a 00 ml two-necked flask, 3.25 g of poly (1,4-diethynylbenzene / methylphenylsilane) (2.0
mmol), was dissolved in toluene 30 ml, and the reaction mixture was heated to 60 ° C., the catalyst (H ₂ PtCl ₆ · 6H ₂
O) 1 ml of a solution of 0.011 g (0.02 mmol) in isopropanol was added, and the mixture was stirred for 10 minutes. Then
0.39 g of 1,4-bis (dimethylsilyl) benzene
After dropping 15 ml of a toluene solution of (2.0 mmol),
The temperature of the oil bath was raised to 75 ° C., and the mixture was heated under reflux for 10 hours. Next, the reaction solution was cooled to room temperature, and methanol 5 was added.
Poured into 00 ml. The resulting precipitate was separated by filtration to obtain 3.1 g of a yellow-white powder (polymer). The weight average molecular weight of this polymer was 9,400 in terms of polystyrene.

The polymers obtained in Example 1 and Comparative Example 1 were placed in an aluminum mold, heated at 240 ° C. for 2 hours, and melt-molded to obtain a molded body. The heat resistance of this molded product was measured using “SSC5200 system” manufactured by Seiko Denshi Co., Ltd., and the measurement results are shown in FIG. Further, 5 wt% decomposition temperature in air atmosphere of the molded body (Td _5), and 800
Table 1 shows the residual weight ratio (W ₈₀₀ ) at ° C.

[0050]

[Table 1]

From Table 1, it can be seen that the carborane-containing silicon-based polymer of Example 1 did not decompose up to 5% by weight up to 800 ° C. and was a material having extremely excellent heat resistance.

Further, the heat resistance of the molded article of the silicon-based polymer obtained in Example 1 and the molded article of the cured silicon-based resin obtained by thermally crosslinking the silicon-based polymer of Example 1 were evaluated. Was. The measurement was performed using “SSC120 manufactured by Seiko Instruments Inc.
250 mm for a 10 mm thick molded body sample
10 ° C from room temperature to 400 ° C under a load of g
The change in sample thickness when the temperature was raised at a rate of temperature rise of 1 / min was evaluated. From the measurement results shown in FIG. 5, it can be confirmed that the heat resistance is improved by performing the thermal crosslinking reaction.

[0053]

As described above, the silicon-based polymer of the present invention is excellent in heat resistance and 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 silicon-based polymer of Example 1.

FIG. 2 is an IR spectrum of the silicon-based polymer of Example 1.

FIG. 3 is an IR spectrum of the silicon-based polymer of Example 1 and a cured silicon-based resin obtained by thermally crosslinking the same.

FIG. 4 is a thermal decomposition curve of the silicon-based polymer of Example 1 and the polymer of Comparative Example 1.

FIG. 5 is a thermal decomposition curve of the silicon-based polymer of Example 1 and a silicon-based resin cured product obtained by thermally crosslinking the same.

Claims (3)

[Claims] 1. A carborane-containing silicon-based polymer having a structural unit represented by the general formula (1) in its structure and having a weight average molecular weight of 500 or more. Embedded image [In the formula (1), R ¹ is a hydrogen atom bonded to a silicon atom,
Represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 30 carbon atoms, which may be the same or different. CBpHp'C represents carborane which is a divalent cage-like boron compound, p and p 'represent integers of 3 to 16, and n and m represent integers. In the formula (1), U represents a repetition of a silicon-based polymer having the following formulas (2) and (3) as components, and V represents a silicon having the following formulas (3) and (4) as components. Represents the repetition of a series polymer] Embedded image Embedded image [In the formulas (2), (3) and (4), R ^{1 to} R ⁵ represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 30 carbon atoms, and May also be different. The positions of the ethynylene group and R ^{2 to} R ⁵ with respect to the benzene ring are arbitrary. 2. A silyl-substituted carborane derivative represented by the general formula (5) and a terminal triple bond of a main chain of a silicon-based polymer represented by the general formulas (6), (7) and (8). The method for producing a carborane-containing silicon-based polymer according to claim 1, wherein the reaction is carried out. Embedded image Embedded image Embedded image Embedded image [In the formula (5), R ¹ is a hydrogen atom bonded to a silicon atom,
Represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 30 carbon atoms, which may be the same or different. CBpHp'C represents carborane which is a divalent cage-like boron compound, and p and p 'represent integers of 3 to 16. In the formulas (6), (7) and (8), X represents a structural unit represented by the following general formula (9), Y represents a structural unit represented by the following general formula (10), and m represents an integer. Embedded image Embedded image [In the formula (9), R ^{2 to} R ⁵ represent a hydrogen atom and a carbon number of 1 to 2;
0 represents an alkyl group or an aryl group having 6 to 30 carbon atoms, which may be the same or different. The positions of the ethynylene group and R ^{2 to} R ⁵ with respect to the benzene ring are arbitrary. In the formula (10), R ⁶ represents 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, which may be the same or different. 3. A carborane-containing silicon-based resin cured product obtained by crosslinking the carborane-containing silicon-based polymer according to claim 1.