JP3290463B2 - Thermosetting silicon boron-containing copolymer and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermosetting copolymer and a method for producing the same. This copolymer is a copolymer of a thermoplastic silicon-containing polymer and polyborosilazane and exhibits thermosetting properties, so it can be directly converted to ceramics by thermal decomposition, and can be used for ceramic fibers, ceramic coatings, ceramic adhesives, etc. Useful as a precursor polymer.

[0002]

2. Description of the Related Art Silicon carbide is excellent as a structural material, but polycarbosilane, polysilastyrene, polysilane and the like are known as precursor polymers thereof (Cera).
m. Eng. Sci. Proc. , 97-7, 198
8 years, pages 931 to 942; JP-A-51-126300, JP-A-52-74000 and JP-A-52-1270.
No. 0).

[0003] Also, as precursors of silicon carbide ceramics such as SiC-TiC, polytitanocarbosilane, polyzirconocarbosilane, polydisiylazane and the like are known (US Patent Nos. 4,340,619 and 4). , 32
1,970, 4,482,689, Tokuhei 2-3
No. 3734, No. 2-37333, JP-B-61-580
No. 86, 62-61220 and the like).

On the other hand, the present inventors have developed and disclosed polyborosilazane as a precursor of boron-containing silicon nitride ceramics (JP-A-2-84437).

[0005]

Since all of the above-mentioned polymers which are precursors of silicon carbide or silicon carbide ceramics are thermoplastic, an infusibilization step is indispensable when producing a ceramic product therefrom. As the infusibilization method, thermal oxidation, steam treatment, γ-ray irradiation, electron beam irradiation, ultraviolet irradiation, halogen treatment, ozone treatment, etc. are known, but the treatment method is complicated, and it is dangerous because it handles radiation, There are problems such as inefficiency and the inclusion of impurities. In particular, oxygen introduced by thermal oxidation causes deterioration of high-temperature characteristics of ceramics.

Although boron-containing silicon nitride ceramics are high-temperature structural materials having excellent strength, toughness, etc., silicon carbide can provide a structural material with higher strength. The composite is expected to provide a ceramic having more excellent characteristics with a controlled microstructure. Therefore, the present invention widely converts a thermoplastic polymer into a thermosetting one, and provides a polymer useful as a precursor of ceramics which does not require an infusibilization step. An object is to provide a polymer useful as a precursor of a composite ceramic.

[0007]

The above object has been achieved by copolymerizing a thermoplastic silicon-containing polymer and a thermosetting polyborosilazane, and if necessary, adding a metal compound to crosslink. Can be promoted. Thus, according to the present invention, the number average molecular weight is 200 to 5
The number average molecular weight of the polyborosilazane block A of 000 and the thermoplastic silicon-containing polymer block B having a number average molecular weight of 100 to 50,000 is 300 to 50.
000 block copolymer, wherein said block A is mainly of the formula (i) or (ii) or (iii) or (iv)

[0008]

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(Wherein R ¹ is a hydrogen atom, a halogen atom,
An alkyl group having 1 to 20 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, an alkoxy group, an alkylamino group, a hydroxyl group, or an amino group, and R ² is a group having a nitrogen atom among R ¹ A residue bonded to a nitrogen atom. In formula (iv), at least two of a total of six atoms each consisting of three nitrogen atoms and a boron atom are used for crosslinking, and the remaining atoms are represented by R ^One can be combined. A) a thermosetting copolymer having a cross-linked bond represented by the formula (1) and a polyborosilazane block having a B / Si atomic ratio in the range of 0.01 to 3; Polyborosilazane having an average molecular weight of 200 to 50,000 and a number average molecular weight of 100 to 50,000
There is provided a method characterized by reacting with zero thermoplastic silicon-containing polymer.

[0010] In the above-mentioned production method, a polyborosilazane and a thermoplastic silicon-containing polymer may be used together with a formula MX.
_n (wherein, M is at least one metal element selected from B, Al, Ti, Zr, and Hf, X may be the same or different, and may be a hydrogen atom, a halogen atom, a hydroxyl group, a carbonyl group, or An alkoxy group, a phenoxy group, an acetylacetoxy group, an alkyl group, an alkenyl group, a cycloalkyl group, an alkylamino group or an amino group having 1 to 20 carbon atoms, and n is a valence number of the metal element M. ) Is reacted at an atomic ratio of (Si in all components) / M of 500 or less, and a thermosetting copolymer obtained by this manufacturing method. Is also provided.

Polyborosilazane can be converted to Si-
Coupling with many thermoplastic silicon-containing polymers having an H bond or an N—H bond, a copolymer composed of a polyborosilazane block and a thermoplastic silicon-containing polymer block is composed of a polyborosilazane block and a thermoplastic silicon-containing polymer. A structure in which blocks and main chains are bonded to each other, or a structure in which side chains of these blocks are reacted and crosslinked,
Alternatively, it may be a structure having both of them. When a functional group is present in the thermoplastic silicon-containing polymer, the polyborosilazane reacts with many of the functional groups in the thermoplastic silicon-containing polymer to form bonds only by heating.
When there is no functional group or when the reactivity is low, a bond can be easily formed by introducing a reactive group into the terminal or side chain of the thermoplastic silicon-containing polymer.

The polyborosilazane used in the present invention is mainly represented by the general formula (I):

[0013]

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(Wherein R^Three, R^Four, R^FiveAre independent
To hydrogen, alkyl, alkenyl, cycloalkyl
Group, aryl group, or other than these groups,
A group in which the linking group is carbon, an alkylsilyl group, or an alkyl
Represents an amino group or an alkoxy group. Where R^Three, R^Four,
R^FiveAt least one is a hydrogen atom, preferably R
^Three, R^Four, R^FiveAre all hydrogen atoms. )
Having a main skeleton consisting of units having a number average molecular weight of about 10
0 to 50,000 polysilazane, and the compounds represented by general formulas (II), (III),
(IV) or (V):

[0015]

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(In these formulas, R ⁶ may be the same or different, and represent a hydrogen atom, a halogen atom,
An alkyl group, alkenyl group, cycloalkyl group, aryl group, alkoxy group, alkylamino group, hydroxyl group or amino group having 20 groups, and L is a compound which forms a complex with B (R ⁶ ) ₃ . The boron / silicon atom ratio obtained by reacting the boron compound represented by
1 to 3 and a number average molecular weight of about 200 to 50,0.
00 polyborosilazane can be used (for details, refer to JP-A-2-84437). When the above polysilazane (I) is perhydropolysilazane,
It has excellent thermosetting properties, improves the ceramic yield of the copolymer, can control the generation of free carbon in ceramics,
There are advantages such as that the ceramic retains an amorphous to microcrystalline structure up to a high temperature.

Polyborosilazane has Si—H, NH bonds and is highly reactive, so that it is easy to copolymerize and is thermosetting, and is therefore most suitable for the purpose of the present invention. Further, in the copolymerization with the SiC precursor polymer, the amount of B can be freely controlled, so that there is an effect of controlling the fine structure of the ceramic. The molecular weight of polyborosilazane has a number average molecular weight in the range of 200 to 50,000. If the molecular weight is smaller than this, a high molecular weight copolymer excellent in ceramic yield cannot be obtained. On the other hand, if it is larger than this, gelation occurs by polymerization.

The thermoplastic silicon-containing polymer that can be used in the present invention can be polysilane containing silicon in the main chain, polycarbosilane, polysiloxane, polysilazane, and the like. Carbosilane, polysilastyrene, polycarbosilastyrene, methylpolysilane, phenylpolysilane,
Polytitanocarbosilane, polyzirconocarbosilane,
Polydisilylazane or the like can be preferably used. When these polymers have a group that reacts with polyborosilazane, a copolymer is formed by directly mixing and heating both polymers. The groups that react with polyborosilazane include amide groups, imide groups, hydrosilyl groups, hydroxyl groups, alkoxy groups, carboxyl groups, keto groups, halogen atoms, epoxy groups, and the like.

The molecular weight of the thermoplastic silicon-containing polymer is:
Those having a number average molecular weight in the range of 100 to 50,000 are used. If the molecular weight is smaller than this, it evaporates during the reaction, and the polymer yield is low. If it is larger than this, the copolymer gels due to polymerization. As noted above, many thermoplastic silicon-containing polymers and polyborosilazanes form bonds upon direct heating. Usually, a solvent is used, but the solvent may be any one that does not react with the thermoplastic silicon-containing polymer and polyborosilazane, for example, methylene chloride, chloroform,
Halogenated hydrocarbons such as carbon tetrachloride, bromoform, ethylene chloride, ethylidene chloride, trichloroethane, tetrachloroethane, ethyl ether, isopropyl ether, ethyl butyl ether, butyl ether, 1,2-
Ethers such as dioxyethane, dioxane, dimethyldioxane, tetrahydrofuran, tetrahydropyran, pentane, hexane, isohexane, methylpentane, heptane, isoheptane, octane, isooctane, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, benzene, toluene,
Hydrocarbons such as xylene and ethylbenzene. The reaction temperature is not limited, but is preferably in the range of 0 to 300 ° C. The reaction time may usually be 30 minutes or more.

In addition, when the thermoplastic silicon-containing polymer has or does not have a group that reacts with polyborosilazane, a metal compound can be further added for crosslinking. As the metal compound forming a cross-linking, for example, halides such as B, Al, Ti, Zr, Hf, hydroxides, alkylated compounds, alkoxides, acetylacetonates, metallocenes and the like can be used. These metal compounds react with hydrogen atoms or side groups bonded to the silicon, nitrogen or boron atoms of the polyborosilazane, and also react with side groups of the thermoplastic silicon-containing polymer to form mainly polyborosilazane. A silicon, nitrogen or boron atom of the above and a silicon or other atom constituting the main chain of the thermoplastic silicon-containing polymer are bonded via a metal atom to form a cross-linking bond. Alternatively, it reacts with a reactive site in the side chain group of the thermoplastic silicon-containing polymer to form a cross-link via the side chain. By introducing such a cross-linking, a copolymer sufficiently reflecting the thermosetting property of polyborosilazane can be obtained.

The amount of the metal compound for forming the cross-linking is preferably such that the ratio of the number of metal atoms to the total number of silicon atoms in the starting polymer is 500 or less. Thus, according to the present invention, a metal compound is added to the thermoplastic silicon-containing polymer and the polyborosilazane and mixed together with the thermosetting copolymer obtained by directly bonding the thermoplastic silicon-containing polymer and the polyborosilazane. A thermosetting copolymer obtained by the reaction is also provided. The molecular weight of the resulting copolymer is generally in the range from 300 to 500,000. If the molecular weight is too large, a gel is formed, and the solubility in a solvent is significantly deteriorated.

The ratio of the polyborosilazane block to the thermoplastic silicon-containing polymer block in the obtained polymer is not particularly limited as long as the polymer becomes thermosetting as a result, but is generally included in each block. The ratio of silicon atoms is 0.5 or more, preferably 1 or more. When this ratio is large, the thermosetting polyborosilazane block inhibits the softening of the thermoplastic block, and as a result, a thermosetting copolymer is obtained.

The thermosetting copolymer thus obtained is soluble in an organic solvent, and a shaped ceramic can be easily obtained. Further, impurities mixed in the infusibilization step can be suppressed.
Compared to SiC obtained from the silicon carbide precursor polymer, B and N are introduced into SiC derived from the thermosetting copolymer, so that the amorphous to microcrystalline structure is maintained up to a high temperature. Therefore, the high-temperature strength of the structural material obtained from the thermosetting copolymer can be improved.

In addition, there are various forms of producing a ceramic product using the thermosetting copolymer as a ceramic precursor, such as a method of directly shaping and firing, a method of impregnating a preform, and a method of using as a binder. In these cases, in order to convert the thermosetting copolymer into a ceramic, the solid polymer is dissolved in a solvent,
After removing the solvent until it has the required viscosity, it is shaped into fibers and membranes, impregnated into preforms, and mixed with ceramic powder. After removing the solvent as needed, thermal decomposition is performed.

The liquid polymer is shaped into fibers and membranes, impregnated into preforms, mixed with ceramic powder, and then heat-cured. Then, pyrolysis is performed. The thermal decomposition is performed in a He, Ar, N ₂ , H ₂ atmosphere, a mixed atmosphere thereof, or a pressurized atmosphere or a reduced pressure atmosphere thereof. The temperature is preferably from 600C to 1800C.

[0026]

[Function] By block copolymerizing polyborosilazane with a thermoplastic silicon-containing polymer such as a silicon carbide precursor polymer, the polymer becomes thermosetting, and the infusibilization step is not required in the ceramicization step. The process is simplified, and there is no risk of impurities being mixed into the obtained ceramic. In particular, by performing block copolymerization of a silicon carbide precursor polymer and polyborosilazane, a ceramic having excellent properties of both silicon carbide and silicon nitride and controlling the microstructure by introducing B is used as described above. It can be manufactured by a simple method without an infusibilizing step. Since the crystal growth can be suppressed by introducing B, the fine structure of the ceramic can be controlled to be amorphous or microcrystalline.

[0027]

Reference Example 1 A four-necked flask having an internal volume of 11 was equipped with a gas blow-in tube, a mechanical stirrer, and a dewar condenser. After the inside of the reactor was replaced with deoxygenated dry nitrogen, 490 ml of degassed dry pyridine was placed in a four-necked flask and cooled with ice. Next, 51.6 g of dichlorosilane was added, and a white solid adduct (SiH ₂ Cl ₂ .2C ₅ H ₅ N) was added.
Generated. The reaction mixture was ice-cooled, and while stirring, 51.0 g of purified ammonia was blown through a sodium hydroxide tube and an activated carbon tube.

After completion of the reaction, the reaction mixture was centrifuged, washed with dry pyridine, and then filtered under a nitrogen atmosphere to obtain 850 ml of a filtrate. The solvent was distilled off from 5 ml of the filtrate under reduced pressure to give a resin solid perhydropolysilazane 0.102.
g was obtained. The number average molecular weight of the obtained polymer is GP
It was 980 as measured by C. The IR (infrared absorption) spectrum of this polymer (solvent: dry o)
Concentration of xylene; perhydropolysilazane: 10.2
g / l), the wave numbers (cm ^-1 ) 3350 and 11
It was confirmed to show absorption based on NH of 75; absorption based on SiH of 2170; absorption based on SiH and SiNSi of 1,020 to 820. The ¹ H
NMR (proton nuclear magnetic resonance) spectrum (60 MHz,
Examination of the solvent CDCl ₃ / reference substance TMS) confirmed that all showed broad absorption. That is, δ
4.8 and 4.4 (br, SiH); 1.5 (br, N
H) was confirmed.

REFERENCE EXAMPLE 2 100 ml of the pyridine solution of perhydropolysilazane (concentration of perhydropolysilazane, 5.04% by weight) obtained in Reference Example 1 was placed in a 300 ml pressure-resistant reaction vessel.
2.8 g (0.165 mol) of purified anhydrous ammonia was added, and the reaction was carried out while stirring at 80 ° C. for 6 hours in a closed system. During this time, a large amount of gas was generated. The pressure increased by 1.2 kg / cm ² before and after the reaction. After cooling to room temperature, 200 ml of dry o-xylene was added, the pressure was 3-5 mmHg, and the room temperature was 50-70.
After removing the solvent at ℃, 5.22 g of white powder was obtained. This powder was soluble in toluene, tetrahydrofuran, chloroform and other organic solvents.

The number average molecular weight of the polymer powder is GPC
Was 2,440. Also, I
Analysis of the R spectrum (solvent: o-xylene) revealed that the wavenumbers (cm ^-1 ) were based on NH at 3350 and 1175; the absorption based on SiH at 2170;
Was confirmed to exhibit absorption based on SiH and SiNSi. Further, when the ¹ H NMR spectrum (CDCl ₃ , TMS) of the polymer powder was analyzed, each of them showed a wide absorption. That is, δ4.8 (br,
SiH ₂ ), δ 4.4 (br, SiH ₃ ), δ 1.5
(Br, NH) absorption was observed. (SiH ₂ ) /
(SiH ₃ ) = 4.1.

Reference Example 3 100 ml of the pyridine solution of perhydropolysilazane (concentration of perhydropolysilazane, 5.24% by weight) obtained in Reference Example 1 was put into a pressure-resistant reaction vessel having an internal volume of 300 ml.
The reaction was carried out while stirring at 120 ° C. for 3 hours in a nitrogen atmosphere and a closed system. During this time, a large amount of gas was generated. The pressure increased by 1.0 kg / cm ² before and after the reaction. After cooling to room temperature, 200 ml of dry ethylbenzene was added, and the solvent was removed at a pressure of 3 to 5 mmHg and a room temperature of 50 to 70 ° C to obtain 4.68 g of a white powder. This powder was soluble in toluene, tetrahydrofuran, chloroform and other organic solvents.

The number average molecular weight of the polymer powder is determined by GPC
Was 2,370. Also, I
As a result of the analysis of the R spectrum (solvent: ethylbenzene),
Wave number (cm ^-1 ) 3350 and 1175 based on NH; 2170 based on SiH;
Was confirmed to exhibit absorption based on SiH and SiNSi. Further, when the ¹ H NMR spectrum (CDCl ₃ , TMS) of the polymer powder was analyzed, each of them showed a wide absorption. That is, δ4.8 (br,
SiH ₂ ), δ 4.4 (br, SiH ₃ ), δ 1.5
(Br, NH) absorption was observed. (SiH ₂ ) /
(SiH ₃ ) = 4.1.

Reference Example 4 100 ml of the pyridine solution of perhydropolysilazane (perhydropolysilazane concentration: 5.10% by weight) obtained in Reference Example 2 was placed in a pressure-resistant reaction vessel having an internal volume of 300 ml.
After adding 4.0 cc (0.035 mol) of trimethyl borate, the reaction was carried out while stirring at 160 ° C. for 3 hours in a closed system. The pressure increased by 1.0 kg / cm ² before and after the reaction. The generated gas was measured by gas chromatography (GC).
Hydrogen and methane. After cooling to room temperature, 100 ml of dry φ-xylene was added, the pressure was 3-5 mmHg, and the temperature was 50-7.
After removing the solvent at 0 ° C., 5.45 g of a white powder was obtained. This powder, toluene, tetrahydrofuran,
It was soluble in chloroform and other organic solvents.

The number average molecular weight of the polymer powder is determined by GPC
Was 2,100. In addition, as a result of analysis of the IR spectrum, absorption based on NH at wave numbers (cm ⁻¹ ) of 3350 and 1175; absorption based on SiH at 2170;
absorption based on i; CH of 2960, 2940, 2840
Absorption based on 1090; absorption based on SiO; 155
It was confirmed to exhibit an absorption based on BO of 0 to 1300. Further, the ¹ H NMR spectrum (C
As a result of analyzing DCL ₃ , TMS, δ 4.8 (br,
SiH ₂ ), δ 4.7 (br, OSiH ₂ ), δ 4.4
(Br, SiH ₃ ), δ 3.6 (br, CH ₃ O), δ
1.4 (br, NH) absorption was observed. The results of elemental analysis of the polymer were as follows: Si: 42.4%, N: 25.9%, C: 8.8%, O: 12.7%, B: 7.0%, H : 3.8%.

Reference Example 5 100 ml of the φ-xylene solution of perhydropolysilazane (concentration of perhydropolysilazane; 10.4% by weight) obtained in Reference Example 3 was placed in a pressure-resistant reaction vessel having an internal volume of 300 ml, and boron trichloride 17 Then, 0.3 g (0.283 mol) was added, and the reaction was carried out while stirring at 20 ° C. for 3 hours in a closed system. The white precipitate was separated by filtration, and the solvent of the filtrate was distilled off under reduced pressure in the same manner as in Reference Example 4 to obtain 8.2 g of a colorless and transparent rubbery solid. The number average molecular weight of this substance was 2,890 as measured by GPC.

[0036]Reference example 6 Φ-xy of the perhydropolysilazane obtained in Reference Example 1
Len solution (concentration of perhydropolysilazane; 5.84
100% into a pressure-resistant reaction vessel with an internal volume of 300 ml
Pyridine-borane complex 4.0 cc (0.0396 mol
 ) And react with stirring at 80 ° C for 3 hours in a closed system.
Was performed. 0.2kg / cm before and after reaction ^TwoRise
Was. The generated gas was hydrogen by GC measurement. reference
When the solvent was distilled off under reduced pressure in the same manner as in Example 4, a reddish brown solid was obtained.
4.98 g were obtained. The number average molecular weight of this material is GP
It was 170,000 as measured by C.

Reference Example 7 100 ml of the pyridine solution of perhydropolysilazane (perhydropolysilazane concentration: 5.37% by weight) obtained in Reference Example 2 was placed in a pressure-resistant reaction vessel having an internal volume of 300 ml.
3.2 ml of 1,3,5-trimethylborazine (0.037
6 mol), and the reaction was carried out with stirring at 120 ° C. for 3 hours in a closed system. The pressure increased by 0.3 kg / cm ² before and after the reaction. The generated gas was hydrogen by GC measurement. After cooling to room temperature, the solvent was distilled off under reduced pressure in the same manner as in Reference Example 4 to obtain 4.86 g of a white powder. This powder was soluble in toluene, tetrahydrofuran, chloroform and other organic solvents. The number average molecular weight of this polymer powder was 2,430 as measured by GPC.

[0038]Reference Example 8 Pyridine of perhydropolysilazane obtained in Reference Example 3
Solution (concentration of perhydropolysilazane; 6.32 weight
%) Into a pressure-resistant reaction vessel having an internal volume of 300 ml,
5.5 ml (0.0379 mol) of trimethoxyboroxine
And stirred at 140 ° C for 3 hours in a closed system to carry out the reaction.
Done. 0.2kg / cm before and after reaction ^TwoRose.
The generated gas was hydrogen and methane by GC measurement.
Was. After cooling to room temperature, the solvent was distilled off under reduced pressure as in Reference Example 4.
As a result, 5.77 g of a white powder was obtained. This powder
End with toluene, tetrahydrofuran, chloroform
And other organic solvents. This polymer powder
Has a number average molecular weight of 2640 as measured by GPC.
Met.

REFERENCE EXAMPLE 9 100 ml of the pyridine solution of perhydropolysilazane (concentration of perhydropolysilazane; 5.80% by weight) obtained in Reference Example 2 was placed in a 300 ml pressure-resistant reaction vessel, and tris (dimethylamino) was added. 7.5 ml of borane and 2.5 g of anhydrous ammonia were added, and the reaction was carried out while stirring at 80 ° C. for 3 hours in a closed system. After cooling to room temperature, the solvent was distilled off under reduced pressure in the same manner as in Reference Example 4 to obtain 10.7 g of a white powder. This powder was soluble in toluene, tetrahydrofuran, chloroform and other organic solvents. The number average molecular weight of this polymer powder was 2,880 as measured by GPC.

Example 1 φ-xylene solution 5 of polycarbosilane (manufactured by Shin-Etsu Chemical)
0.65 g of titanium n-butoxide was added to 0 ml (2.43 g of polycarbosilane), and the mixture was refluxed for 1 hour in N ₂ . After cooling to room temperature, 40 ml of the φ-xylene solution of polyborosilazane obtained in Reference Example 4 (polyborosilazane 1.9)
4 g) was added and heated at 100 ° C. for 1 hour in N ₂ . After cooling to room temperature, the solvent was removed at a pressure of 3 to 7 mmHg and a temperature of 50 to 70 ° C. to obtain 4.82 g of a black-blue powder.
This powder was soluble in toluene, tetrahydrofuran, chloroform and other organic solvents.

The number average molecular weight of the polymer powder is determined by GPC
Was 2540. Also,
As a result of the IR spectrum analysis, the wave number (cm^-1) 3350
And 1170 based on NH; 2170 and 21
Absorption based on SiH of 20;
And SiNSi based absorption; 1250 SiCH _Three
Absorption based on 1100; absorption based on SiO; 295
0, 2900, 2880, 1470-1360 CH
1550-1300 BO / BN based absorption
It was confirmed that it showed a profit. Further, the polymer powder¹
HNMR spectrum (CDCl_Three, TMS)
However, all show broad absorption. That is, δ
4.8 (br, SiH_Two), Δ 4.3 (br, Si
H_Three), Δ 0.2 (br, SiCH_Three), Δ1.4 and
δ 0.9 (br, CH), δ 3.7 (br, -C-CH
_TwoO) was observed.

The above polymer powder was placed in N ₂ at 1500 ° C.
, A black solid was obtained in a yield of 70% by weight. No melting was observed during pyrolysis. Example 2 200 ml of anhydrous benzene, 20 g of metallic sodium and 7 g of metallic potassium were added to the four-necked flask of 11 and kept at 70 ° C. 25 g of methyldichlorosilane, 30 g of dimethyldichlorosilane and 50 g of trimethylchlorosilane were added dropwise thereto, and the reaction was carried out for 24 hours.
A pale yellow polysilane having an iH bond was obtained. 300ml
2.0 g of this polysilane, 0.5 g of zirconium isopropoxide and 40 ml of φ-xylene were added to a four-necked flask, and the mixture was heated and refluxed in N ₂ for 3 hours. After cooling to room temperature,
100 ml (5.4 g of polyborosilazane) of the polyborosilazane obtained in Reference Example 5 in φ-xylene was added, and N ₂ was added.
And heated at 120 ° C. for 1 hour. After cooling to room temperature, pressure 3
~ 7mmHg, 50 ~ 70 ° C temperature and the solvent was removed,
7.22 g of a pale yellow powder were obtained. This powder was soluble in toluene, tetrahydrofuran, chloroform and other organic solvents.

The number average molecular weight of the polymer powder is determined by GPC
It was 3100 when measured by. Further, when the polymer powder was thermally decomposed in Ar at 1500 ° C.,
A black solid was obtained with a yield of 85 wt%. No melting was observed during pyrolysis. Example 3 φ-xylene solution 4 of polysilastyrene (manufactured by Nippon Soda)
Hafnium-n in 0 ml (1.84 g of polysilastyrene)
0.7 g of butoxide was added, and the mixture was heated under reflux in N ₂ for 1 hour. After cooling to room temperature, 50 ml of the polyborosilazane φ-xylene solution obtained in Reference Example 6 (polyborosilazane 2.
56 g) was added and heated at 100 ° C. for 30 minutes in N ₂ . After cooling to room temperature, pressure 3-7mmHg, temperature 50-70 ° C
After removing the solvent with, 4.75 g of a yellow powder was obtained.

When this powder was pyrolyzed at 1500 ° C. in N ₂ , a black solid was obtained in a yield of 85% by weight. No melting was observed during pyrolysis. Example 4 A 500-ml four-necked flask was equipped with a mechanical stirrer, a gas inlet tube, a cooling tube, and a dropping funnel. Here 5
0 g of a disilane mixture (tetrachlorodimethyldisilane 50 wt%, trichlorotrimethyldisilane 50 wt%) was introduced, and the mixture was kept in an N ₂ atmosphere and hexamethyldisilazane 1 was added.
20 g was added to disilane from a dropping funnel. The mixture was heated to 220 ° C. under N ₂ while removing by-products. After maintaining at 220 ° C. for 3 hours, the mixture was cooled to room temperature, whereby a cloudy glassy polymer was obtained. 300 ml of dry toluene was added thereto to dissolve the polymer, and this solution was filtered through a 1.0 μm membrane filter. When the solvent of the filtrate was removed, 22.5 g of a pale yellow resinous solid was obtained. The softening point of this resin was about 80 ° C.

1.5 g of the above polymer was added to 30 ml of φ-xy
It was dissolved in ren and introduced into a 300 ml four-necked flask. This
Here, φ-xylene of the polyborosilazane obtained in Reference Example 7 was used.
100 ml (4.30 g of polyborosilazane)
Well, it was ice-cooled. Here, triethylaluminum 0.15
g, gradually heated to 80 ° C., and maintained for 1 hour.
After cooling to room temperature and removing the solvent, 5.45 g of a pale yellow powder was obtained.
Obtained. This powder is N _TwoThermal decomposition at 1500 ℃
And a black solid were obtained in a yield of 80% by weight. Dissolved during pyrolysis
No melting was observed.Example 5 Φ-xylene solution of polycarbosilane (Shin-Etsu Chemical) 5
0 ml (2.50 g of polycarbosilane) in titanium-n-butyl
0.80 g of toxide is added, and N_TwoAnd heat for 1 hour to reflux
Was. After cooling to room temperature, the polyborosilaza obtained in Reference Example 8 was obtained.
40 ml of φ-xylene solution (polyborosilazane 2.7)
4g) and add N_TwoHeated at 100 ° C. for 1 hour. Room
After cooling to the temperature, the pressure is 3 to 7 mmHg, and the temperature is
After removing, 4.96 g of a black-blue powder was obtained.
This powder is composed of toluene, tetrahydrofuran, chloroform
Soluble in organic solvents and other organic solvents. The polymer powder
The number average molecular weight of the powder was measured by GPC and found to be 2
860. Further, the polymer powder is mixed with Ar in 15
Pyrolyzed at 00 ° C, black solid yield of 75wt%
Was obtained. No melting was observed during pyrolysis.

Example 6 A solution of polycarbosilane (Shin-Etsu Chemical) in φ-xylene 5
0 ml (polycarbosilane 2.86 g), 0.45 g of tris (dimethylamino) borane and 0.5 g of anhydrous ammonia
Was placed in a pressure-resistant reaction vessel and reacted at 80 ° C. for 1 hour. After cooling to room temperature, unreacted ammonia was removed, and the polyborosilazane solution obtained in Reference Example 9 in φ-xylene 60
ml (polyborosilazane 3.68 g) was added, in N _2, 1
Heated at 00 ° C. for 1 hour. After cooling to room temperature, pressure 3 ~ 7mm
Hg, at a temperature of 50 to 70 ° C., after removing the solvent, 6.32
g of a pale yellow powder was obtained. This powder was soluble in toluene, tetrahydrofuran, chloroform and other organic solvents. The number average molecular weight of the polymer was 3,100 as measured by GPC. When the polymer powder was thermally decomposed in N ₂ at 1500 ° C., a black solid was obtained in a yield of 77% by weight. No melting was observed during pyrolysis.

[0047]

According to the present invention, a thermosetting copolymer obtained by block copolymerizing a polyborosilazane with a thermoplastic silicon-containing polymer such as a silicon carbide precursor polymer can be obtained. In particular, in ceramics obtained by copolymerization with a SiC precursor polymer, N and B can suppress crystallization of SiC, and do not require an infusibilization step, so there is no introduction of impurities (especially O) and heat resistance. In addition to the above, since free C can be suppressed as compared with ceramics derived from the SiC precursor, there is an effect that the high-temperature oxidation resistance is also excellent.

B has the effect of suppressing the crystal growth of ceramics, but by replacing perhydropolysilazane with polyborosilazane, the amount of B can be controlled in a wide range. As a result, the structure of the induced ceramic can be freely controlled between amorphous and crystalline.

Continuing from the front page (72) Inventor Hideki Matsuo 1-3-1, Nishitsurugaoka, Oimachi, Iruma-gun, Saitama Prefecture Within the Tonen Co., Ltd. (72) Inventor Takeshi Isoda 1-chome, Nishitsurugaoka, Oimachi, Iruma-gun, Saitama No. 3 No. 1 Tonen Co., Ltd. (56) References JP-A-2-84437 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 77/60 C08G 79/08 C08G 81/00

Claims (6)

(57) [Claims] 1. A polyborosilazane block A having a number average molecular weight of 200 to 50,000 and a number average molecular weight of 100 to 50,000.
50,000 thermoplastic silicon-containing polymer blocks B
A number average molecular weight of the block copolymer 300～500,000 consisting of the blocks A mainly one
General formula (I) (Wherein, R ³ , R ⁴ and R ⁵ are each independently a hydrogen atom,
Alkyl group, alkenyl group, cycloalkyl group, aryl
Group or a group other than these groups that is directly connected to silicon
Groups, alkylsilyl groups, alkylamino groups,
Represents a lucoxy group. However, less of R ^3, R ^4, R ⁵
And at least one is a hydrogen atom, preferably R ³ , R ⁴ , R
All ⁵ are hydrogen atoms. ) Of a polysilazane having a main skeleton consisting of units represented by
Si and / or N have a cross-linking represented by the following general formula (i) or (ii) or (iii) or (iv),
A polyborosilazane block having a B / Si atomic ratio in the range of 0.01 to 3 ;
, Polysilastyrene, polycarbosilastyrene, methyl
Polysilane, phenylpolysilane, polytitanocarbo
Silane, polyzirconocarbosilane, polydisiliraza
Thermoplastic silicon-containing resin selected from
A thermosetting copolymer, which is a limer . Embedded image (Wherein, R ¹ is a hydrogen atom, a halogen atom, a carbon atom 1
An alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, an alkoxy group, an alkylamino group, a hydroxyl group, or an amino group having up to 20 groups, and R ² is bonded to the nitrogen atom of the group having a nitrogen atom in R ¹ In formula (iv), at least two of a total of six atoms consisting of three nitrogen atoms and three boron atoms are used for crosslinking, and R ¹ is bonded to the remaining atoms. be able to. ) 2. The thermosetting copolymer according to claim 1, wherein the atomic ratio of Si contained in the block A to Si contained in the block B is 1 or more. (3) a compound represented by the general formula (I) : (Wherein, R ³ , R ⁴ and R ⁵ are each independently a hydrogen atom,
Alkyl group, alkenyl group, cycloalkyl group, aryl
Group or a group other than these groups that is directly connected to silicon
Groups, alkylsilyl groups, alkylamino groups,
Represents a lucoxy group. However, less of R ^3, R ^4, R ⁵
And at least one is a hydrogen atom, preferably R ³ , R ⁴ , R
All ⁵ are hydrogen atoms. ) Of a polysilazane having a main skeleton consisting of units represented by
The following general formula (i) or (ii) or (iii) or (iv) is added to Si and / or N. (Wherein, R ¹ is a hydrogen atom, a halogen atom, a carbon atom 1
An alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, an alkoxy group, an alkylamino group, a hydroxyl group, or an amino group having up to 20 groups, and R ² is bonded to the nitrogen atom of the group having a nitrogen atom in R ¹ In formula (iv), at least two of a total of six atoms consisting of three nitrogen atoms and three boron atoms are used for crosslinking, and R ¹ is bonded to the remaining atoms. be able to. ) Having a B / Si atomic ratio of 0.0
1 to 3 and a number average molecular weight of 200 to 50,000.
Polyborosilazane having a number average molecular weight of 100 to 5
000 polycarbosilane, polysilastyrene,
Ricarbosila styrene, methyl polysilane, phenyl ester
Lysilane, polytitanocarbosilane, polyzirconocal
Chosen from bosilane, polydisilylazane, polysiloxane
The thermoplastic silicon-containing polymer is maintained at 0-300 ° C.
A method for producing a thermosetting copolymer, wherein the reaction is carried out by holding or heating . 4. A compound represented by the general formula (I) : (Wherein, R ³ , R ⁴ and R ⁵ are each independently a hydrogen atom,
Alkyl group, alkenyl group, cycloalkyl group, aryl
Group or a group other than these groups that is directly connected to silicon
Groups, alkylsilyl groups, alkylamino groups,
Represents a lucoxy group. However, less of R ^3, R ^4, R ⁵
And at least one is a hydrogen atom, preferably R ³ , R ⁴ , R
All ⁵ are hydrogen atoms. ) Of a polysilazane having a main skeleton consisting of units represented by
The following general formula (i) or (ii) or (iii) or (iv) is added to Si and / or N. (Wherein, R ¹ is a hydrogen atom, a halogen atom, a carbon atom 1
An alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, an alkoxy group, an alkylamino group, a hydroxyl group, or an amino group having up to 20 groups, and R ² is bonded to the nitrogen atom of the group having a nitrogen atom in R ¹ In formula (iv), at least two of a total of six atoms consisting of three nitrogen atoms and three boron atoms are used for crosslinking, and R ¹ is bonded to the remaining atoms. be able to. ) Having a B / Si atomic ratio of 0.0
1 to 3 and a number average molecular weight of 200 to 50,000.
Polyborosilazane having a number average molecular weight of 100 to 5
000 polycarbosilane, polysilastyrene,
Ricarbosila styrene, methyl polysilane, phenyl ester
Lysilane, polytitanocarbosilane, polyzirconocal
Chosen from bosilane, polydisilylazane, polysiloxane
With a thermoplastic silicon-containing polymer of the formula MX _n , wherein
M is at least one metal element selected from B, Al, Ti, Zr, and Hf, X may be the same or different, and may be a hydrogen atom, a halogen atom, a hydroxyl group, a carbonyl group, or a group having 1 carbon atom. 20 to 20 alkoxy groups, phenoxy groups, acetylacetoxy groups, alkyl groups, alkenyl groups, cycloalkyl groups, alkylamino groups or amino groups, and n is the valence of the metal element M. ) And (atomic ratio of (Si in all components) / M) 500 or less from 0 to
Maintain or heat at 300 ° C to react, polyborosila
Zan silicon, nitrogen or boron atoms and thermoplastic silica
Atoms such as silicon that constitute the main chain of the silicon-containing polymer
Cross-linking via a genus atom or thermoplastic
Reacts with reactive sites in the side groups of silicon-containing polymers
A method for producing a thermosetting copolymer , comprising forming a cross-linking via a side chain . 5. The method for producing a thermosetting copolymer according to claim 3, wherein the atomic ratio of Si contained in the polyborosilazane to Si contained in the thermoplastic silicon-containing polymer is 1 or more. 6. A thermosetting copolymer produced by the method according to claim 4.