JPH02175726A - Copolysilazane and its production - Google Patents

Abstract

PURPOSE:To obtain a copolysilazane which is desirable as a silicon nitride precursor and can give a silicon nitride sinter of an extensively cotrollable carbon content when fired at high temperatures by uniting an inorganic polysilazane part having a specified MW with an organic polysilazane part having a specified MW. CONSTITUTION:A block copolysilazane of a number-average MW of 100-50000 consisting of an inorganic polysilazane part A of a number-average MW of 100-50000 and an organic polysilazane part B of a number-average MW of 100-50000. Part A chiefly has a skeleton of formula I, while part B a skeleton of formula II. In formula II, R<1> and R<2> are each a hydrogen atom or an alkyl, alkenyl, cycloalkyl, alkylamino, aryl, aralkyl or alkylsilyl which may have a substituent, provided that the case where both R<1> and R<2> are hydrogen atoms is excluded.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a copolymerized silazane and a method for producing the same, and more particularly to a block copolymerized silazane that can be used as a precursor for silicon nitride and silicon nitride-containing ceramics, and a method for producing the same. [Prior art] Silicon nitride sintered bodies have excellent high-temperature strength, thermal shock resistance, and oxidation resistance, so they are used as high-temperature structural materials for gas turbines, diesel engines, etc., or as cutting tools, etc., for energy saving and saving purposes. It is important as one of the high-performance materials that can make a large contribution to resources. Conventionally, methods for producing silicon nitride include: heating metal silicon powder at 1300°C to 150°C in a nitrogen or ammonia stream;
Silicon direct nitriding method, in which the silicon is directly nitrided by heating at 0°C; ■ Silica reduction method, in which silica or a silica-containing substance is heated together with carbon in a nitrogen atmosphere, the silica is reduced with urea, and the produced silicon reacts with nitrogen. , ■ Gas phase synthesis method in which silicon tetrachloride and ammonia are directly reacted at high temperature, ■ Imide thermal decomposition method in which silicon diimide obtained by ammonolysis of silicon tetrachloride is heated in a non-oxidizing atmosphere to obtain silicon nitride, etc. has been adopted. However, in the case of method (2) above, the reaction time is long, the heating process is complicated, and the silicon nitride obtained is mainly β-type silicon nitride that is coarse and contains many impurities. In method (2), not only is it difficult to purify the raw materials, but the reaction time is long, and the product obtained is a mixed system of α-type silicon nitride and β-type silicon nitride. Generally, silicon nitride is amorphous, and although method (2) has the advantage of producing high-purity α-type silicon nitride in good yield, silicon diimide [Si
(NH)z)x has drawbacks such as being insoluble in solvents and thus having substantially limited uses. Furthermore, a method has recently been proposed in which silicon nitride is synthesized by heating polysilazane obtained by thermally decomposing organic polysilazane at 800 to 2000°C (Hajime Saito, Journal of the Japan Institute of Textile Technology,
VoQ38 Nu1 pages 65-72CL982]
This method has the disadvantage that silicon carbide and free carbon are produced simultaneously with silicon nitride. On the other hand, inorganic polysilazane that is soluble in solvents is
5 tack (Ber, 54. (1,921), p
740) and others, and in 1983, 5
eyferth (Go++++++++, Am. Ceram, Soc, C-13/14+ (83))
It has been demonstrated that it is useful as a silicon nitride precursor. The present inventors focused on this point of view and proposed a method for obtaining highly pure α-type silicon nitride by heat-treating inorganic polysilazane (Japanese Unexamined Patent Publication No. 59-2
No. 07812). [Problems to be Solved by the Invention] However, in all conventional methods for producing inorganic polysilazane, since highly volatile dichlorosilane is used as a raw material, There is a risk that the polysilazane that has been removed may stick and block the gas flow path. ■ To prevent the above-mentioned adverse effects, it is necessary to maintain the reaction temperature at a low temperature to prevent dichlorosilane from scattering. ■ Dichlorosilane is toxic and Since it is highly flammable, it has drawbacks such as being complicated to handle and requiring use in a low-temperature airtight container. Furthermore, in the case of 5tack etc., the synthesized polysilazane is -(SiH2N)l)n
It is only an oligomer of n=7 to 8 having a structure of - and is a viscous liquid at room temperature.
It is an oily liquid with a -H/N-H proton ratio of about 3.3, but since it is heated at about 200°C, it will solidify if left at room temperature for 3 to 5 days. Even so, it could not be said that it had sufficient properties as a precursor for a silicon nitride sintered body shaped at room temperature. In order to solve this problem, the present inventors first developed an inorganic or organic polycarbonate having a silicon-hydrogen bond, R\, RI or -N- (where R and R' have a substituent and suitable as a silicon nitride precursor into which an alkyl group, an alkenyl group, a cycloalkyl group, an alkylamino group, an aryl group, an aralkyl group, or an alkylsilyl group is introduced, and n is 1 or 2. A polysilazane with a high molecular weight was proposed (Japanese Patent Application No. 63-28295, No. 63-28296, No. 63-74919). However, the silicon nitride sintered body obtained by firing the polysilazane at a high temperature has an insufficient range of selection in terms of electrical properties and far-infrared effects. Therefore, according to the present invention, the carbon content in the silicon nitride sintered body obtained after high-temperature firing can be controlled over a wider range, that is, electrical properties and far-infrared effects can be selected over a wider range. The present invention aims to provide polysilazane suitable as a silicon nitride precursor. [Means for Solving the Problems] According to the present invention, the number average molecular weight is 100 to so, oo. Inorganic polysilazane moiety A and number average molecular weight of 100 to 5
A block copolymerized silazane having a number average molecular weight of 200 to 500,000 and consisting of an organic polysilazane moiety B of 0,000, wherein A is mainly a lysilazane block of the formula , R1 and R2 each represent a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an alkylamino group, an aryl group, an aralkyl group, or an alkylsilyl group which may have a substituent.However, R1
and R'' are both hydrogen atoms), and is reacted with an organic polysilazane of formula 00 under basic conditions. A method for producing a polymerized silazane (in the formula, R1 and R2 are the same as above) is provided. The copolymerized silazane of the present invention has a skeleton represented by the following formula (■) and has a number average molecular weight of 100 to 50,000. having an inorganic polysilazane moiety A (hereinafter referred to as block A) and a skeleton represented by the following formula (■) and a number average molecular weight of 10
0 to 50,000 organic polysilazane moiety B (hereinafter referred to as block B) with a number average molecular weight of 200 to 500
,000. In the above formula, R1 and R2 each represent a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an alkylamino group, an aryl group, an aralkyl group, or an alkylsilyl group, which may have a substituent. , R1 and R2 are both hydrogen atoms. In this case, the alkyl group includes methyl, ethyl, propyl, butyl, octyl, decyl, etc., the alkenyl group includes vinyl, allyl, butenyl, octenyl, decenyl, etc., and the cycloalkyl group includes cyclohexyl ,
Examples of the alkylamino group include methylamino group, ethylamino group, etc., examples of the aryl group include phenyl, 1-lyl, xylyl, naphthyl, etc., and examples of the aralkyl group include benzyl. Examples of the alkylsilyl group include methylsilyl, ethylsilyl, propylsilyl, butylsilyl, octylsilyl, decylsilyl, and the like. Further, the substituent may be any substituent as long as it does not show reactivity with the hydrogen atom bonded to the silicon atom, and examples thereof include an alkyl group, an aryl group, an alkoxy group, an alkoxycarbonyl group, and the like. The blocks A and B both have a number average molecular weight of 100 to 50,000 and are made of cyclic polysilazane, chain polysilazane, or a mixture thereof. Blocks A and B are preferred in the present invention. Number average molecular weight 300 to 2,000, particularly preferably 60
It is a chain polysilazane having a molecular weight of 0 to 1,000. In the copolymerized silazane of the present invention, each of the blocks is connected by a head-to-tail bond, or some of the silicon atoms present in the middle of the main chain skeleton of both blocks are ammonia residues, primary They are cross-linked via amine residues, hydrazine residues or substituted hydrazine residues. In this case, the crosslinking bond is expressed by the following general formulas (1) to (
Examples include those represented by Vl). The ratio of block A and block B in the copolymerized silazane is 1001):1 based on the (Si-N) unit.
The range of 1:1000 is preferable. If block B exceeds the above range, free carbon will be generated in the silicon nitride sintered body obtained after firing, resulting in a decrease in mechanical strength. Free silicon is generated and the mechanical strength is reduced. In order to produce the copolymerized silazane of the present invention, the formula is 100-
50,000 and an inorganic polysilazane having the formula (where R
3 and R4 each represent an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, an aralkyl group, or a heterocyclic group which may have a substituent. ) 100 to 50,000 (in the formula,
(R1 and R2 are the same as above) under basic conditions through dehydrogenation polymerization reaction. In addition, when obtaining a copolymerized silazane having a crosslinked bond represented by the general formulas (1) to (VI), ammonia, a primary amine, hydrazine or substituted hydrazine is further added to the anti-core system as a reactant, Obtained by dehydrogenation polymerization reaction. The inorganic and organic polysilazane raw materials can be synthesized by conventionally known methods as shown below. ■Inventor patent application (Unexamined Japanese Patent Publication No. 145903/1983)・
5i82CQ, + 2Py −+ 5iH2CQ2*
2Py adduct・5iH2G4・2Py ad
duct + 3N)l, →-(Sin2NH almost +2N
H, C, Q + 2Py■D, 5eyferth et al. (U
SP 4,397,828)・5jH2CQ2+ 3N
H, Kaikoshi-+5it(z N)廓+2Nll, CA■A
, 5tock (Ber, 54. (1921), P-
740) ■W, M, 5cantlin et al., Inorg.
Chei, 1972.11.2 (H, 3g3N+ JL
H→SiH4+ ((It, 5i)2N:12SiH2
■B, J, Aylett (USP 3,318,823
)・5i11. CQ, +Me2NH→H2Si(N
Me2)2+ Me2NH-)1cQ・H2Si(Me
,)2+ HeNH2→(H,SiNMemost+Ae,N
H+H. ■D, 5eyferth et al. (USP 4,482,66
9) H2CQ2 ・MeSiHC4÷3NH3−→−+H−3iHNH)
i + 2NHqCQ
No. 89230)・MeSi)IC4+ 2Py-+Me
SiHCQ, ・2Py adduct・MeSiHCQ
,・2Py adduct + 3NH1→−(MeS
iHN) I) n+ 2Py + 2NH4CQ In the present invention, the inorganic and organic polysilazane starting materials are subjected to a polymerization reaction under basic conditions. The basic condition means that a basic compound 1 such as tertiary amines, secondary amines having a sterically hindered group, phosphine, etc. is allowed to coexist in the reaction system. Such basic conditions can be formed by adding a basic compound to the reaction solvent, or by using a basic solvent or a mixture of a basic solvent and a non-basic solvent as the reaction solvent. Can be done. The amount of the basic compound added is at least 5 parts by weight, preferably 2 parts by weight, per 100 parts by weight of the reaction solvent.
It is 0 parts by weight or more. If the amount of the basic compound added is less than this, the polymerization reaction will not be smoothly promoted. Any basic solvent can be used as long as it does not decompose the inorganic and organic polysilazane starting materials. Examples of such substances include trialkylamines such as trimethylamine, dimethylethylamine, diethylmethylamine, and triethylamine; tertiary amines such as pyridine, picoline, dimethylaniline, pyrazine, pyrimidine, pyridazine, and derivatives thereof; , pyrrole, 3-pyrroline, pyrazole, 2-pyrazoline, and mixtures thereof. In addition, examples of non-basic solvents include hydrocarbon solvents such as aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons;
Halogenated hydrocarbons such as halogenated methane, halogenated ethane, and halogenated benzene, and ethers such as aliphatic ethers and alicyclic ethers can be used. Preferred solvents include halogenated hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, bromoform, ethylene chloride, ethylidene chloride, trichloroethane, and tetrachloroethane, ethyl ether, isopropyl ether, ethyl butyl ether, butyl ether, 1,2-dioxyethane, and dioxane. , ethers such as dimethyldioxane, tetrahydrofuran, tetrahydropyran, pentane, hexane, isohexane, methylpentane, heptane, isoheptane, octane, isooctane, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, These include hydrocarbons such as ethylbenzene. In a preferred embodiment of the present invention, ammonia, a primary amine, hydrazine or substituted hydrazine is further added as a reactant, and a copolymerized silazane having a crosslinked bond consisting of residues of these compounds is obtained. In this case, as the primary amine, aromatic and aliphatic ones can be used, and the following general formula % formula % In this formula, R3 is an alkyl group which may have a substituent, alkenyl group, cycloalkyl group, aryl group or aralkyl group. Specific examples of this primary amine include methylamine, ethylamine, and propylamine. Isopropylamine, butylamine, isobutylamine, amylamine, hexylamine, heptylamine, octylamine, allylamine, crotylamine, cyclopropylamine, cyclobutylamine, cyclopentylamine, cyclohexylamine, 2-methylcyclohexylamine, 2-amino-1-cyclopentylpropane , aniline, toluidine, benzylamine, naphthylamine and the like. Further, as the substituted hydrazine, a ■-substituted, 1,2-substituted or 1,1-substituted hydrazine can be used, and as the 1-substituted hydrazine, those represented by the following general formula can be used. 4-methylphenylhydrazine, 4-ethylphenylhydrazine, 1-phenylethylhydrazine. 2-phenylethylhydrazine, 1-naphthylhydrazine, 2-naphthylhydrazine, 2-hydrazinobiphenyl, 3-hydrazinobiphenyl, 4-hydrazinobiphenyl, 1-hydrazinophthalazine, 2-hydrazinoquinoline, 3-hydra Examples include dinoquinoline, 4-hydrazinoquinoline, 8-hydrazinoquinoline, and the like. Moreover, as the 1.2-fi substituted hydrazine, those represented by the following general formula can be used. In this formula, R3 represents an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, an aralkyl group, or a heterocyclic group which may have a substituent. Specific examples of this l-substituted hydrazine include methylhydrazine, ethylhydrazine, isopropylhydrazine, propylhydrazine, phenylhydrazine, benzylhydrazine, 2-methylphenylhydrazine,
-Methylphenylhydrazi In this formula, R3 and R4 each represent an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or a heterocyclic group which may have a substituent. Specific examples of this 1,2-fi substituted hydrazine include 1,2-dimethylhydrazine, 1,2-diethylhydrazine, N1-isopropyl-N2-methylhydrazine, 1-methyl-2-phenylhydrazine, 1-ethyl -2-phenylhydrazine, 1,2-dibenzylhydrazine, 2,2'-hydrazobiphenyl, 4,4'-hydrazobiphenyl, 2,2'-dimethylhydrazobenzene, 2,4-dimethylhydrazobenzene , 3,3'-dimethylhydrazobenzene, 3,4'-dimethylhydrazobenzene, 3,5-dimethylhydrazobenzene, 4,4'
-dimethylhydrazobenzene, 2-aminohydrazobenzene, 3-aminohydrazobenzene, 4-7minohydrazobenzene, 1,2-di(1-naphthyl)hydrazine,
1,2-di(2-naphthyl)hydrazine, 2.2',
3.3'-tetramethylhydrazobenzene, 2.2'
, 4.4'-tetramethylhydrazobenzene, 2.2'
, 5,5'-tetramethylhydrazobenzene, 3.3
', 4.4'-tetramethylhydrazobenzene, 3.
Examples include 3'5,5'-tetrahydrazobenzene. Further, as the 1.1-5t-substituted hydrazine, those represented by the first-order general formula can be used. 1 (Xll)
R3-N-NH. In this formula, R3 and R4 are the same as those shown in the general formula (X[). Examples of the 1.1-M-converted hydrazine include trimethylhydrazine, 1,2-dimethyl-1-phenylhydrazine, 1,1-dimethyl-2-phenylhydrazine,
Examples include benzylidenemethylhydrazine. The polymerization reaction of the present invention is preferably carried out in the solvent as described above, but in this case, the concentration of polysilazane (total amount) on the raw material side in the solvent is 0.01 to 60% by weight2, preferably 0.1 to 60% by weight2. 30% heavy weight. If the concentration of the raw material polysilazane is lower than this, the polymerization reaction will not proceed sufficiently, and if it is higher than this, the polymerization reaction will proceed too much and a gel will be produced. The reaction temperature is -78 to 400°C, preferably -40-
The temperature is 250°C, and at a temperature lower than that, the polymerization reaction does not proceed sufficiently, and at a temperature higher than that, the polymerization reaction proceeds too much and forms a gel. When using a reactant such as ammonia, primary amine, hydrazine or substituted hydrazine (hereinafter simply referred to as "reactant such as ammonia"), the amount of the reactant used is as follows:
Molar ratio per mole (average mole) of polysilazane (total lf) on the raw material side, 0.01 to 5000, preferably 0.5
-1000, and if it is lower than that, the polymerization reaction will not proceed sufficiently, and if it is higher than that, the polymerization reaction will proceed too much and a gel will be produced. As the reaction atmosphere, air can be used, but preferably a hydrogen atmosphere, an inert gas atmosphere such as dry nitrogen or dry argon, or a mixed atmosphere thereof is used. Note that when a reactant such as ammonia is used, preferably a basic atmosphere, an inert gas atmosphere, or a mixed atmosphere consisting of ammonia, a primary amine, hydrazine, substituted hydrazine, or the like is used. In the polymerization reaction of the present invention, pressure is applied during the reaction by hydrogen as a by-product and, if a reactant such as ammonia is used, by the reactant compound, but pressurization is not necessarily required. Normal pressure can be used. Furthermore, the reaction time is Although it varies depending on various conditions such as the type and concentration of the inorganic and organic polysilazane starting materials, the type and concentration of the basic solvent, the polymerization reaction temperature, and when adding a reactant such as ammonia, the amount of the reactant added. -0.5~20 for boat fishing
A time range is sufficient. The optimum conditions for the polymerization reaction depend on the average molecular weight and molecular weight distribution of the inorganic and organic polysilazane starting materials, and the molecular structure of the copolymerized silazane.If a reactant such as ammonia is added, which compound should be selected as the reactant. It depends. A general consideration in setting conditions is that the lower the average molecular weight of the starting inorganic and organic polysilazane, the more stringent conditions (temperature, reaction time) are required. In the present invention, when the polymerization reaction is carried out using a basic solvent, the basic solvent solution containing the resulting copolymerized silazane is adjusted to have a basic solvent content of 30% by weight or less in the total solvent. Preferably, it is 5 weight x or less. Since the basic solvent acts as a polymerization reaction catalyst for the copolymerized silazane, if its proportion to the solvent is too large, a gel will be formed during long-term storage at room temperature. Adjustment of the second solvent composition can be carried out, for example, by evaporating the copolymerized silazane solution containing the basic compound obtained in the polymerization reaction step to remove the basic compound contained therein. (reactivity) can be carried out by adding a solvent. When the content of basic compounds in the solution is high or when using basic compounds as the reaction solvent,
A stable solution composition can be obtained by repeatedly performing the solution composition adjustment process consisting of evaporation removal of the basic compound and addition of a non-basic solvent. In the present invention, a stable solution of copolymerized silazane is formed. As other non-basic solvents, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, aliphatic ethers, alicyclic ethers, etc. as shown above can be used. As described above, the copolymerized silazane of the present invention comprises an inorganic polysilazane part A (block A) and an organic polysilazane part B.
(Block B), and its molecular structure is characterized by the new bond described below being formed by the reaction between the IM material inorganic polysilazane and organic polysilazane. (t) Copolymerized silazane of rff claim C1) (i) When R2 of block B is hydrogen (n) When R2 of block B is other than a hydrogen atom Claim (
The copolymerized silazane of 1) has the above-mentioned molecular structural characteristics, and in terms of physical properties, while having crosslinking bonds,
Solid polymers that are soluble in organic solvents, and in particular obtained by removing the solvent from a solution, exhibit a significant feature of being re-soluble in the solvent. Conventional inorganic silazane has poor stability, and when the solvent is removed from its solution, it produces a resinous solid, which is insoluble in the solvent.
The copolymerized silazane of 1) does not exhibit this tendency. Therefore, while conventional inorganic silazane is impossible or extremely difficult to handle as a solid polymer, the copolymerized silazane of claim (1) can be easily handled as a solid polymer. (2) The copolymerized silazane of claim (2), that is, the copolymerized silazane of claim (2), has the general formula (
New crosslinking bonds as shown in I) to (VI) are introduced to increase the molecular weight. The copolymerized silazane of claim (2) is characterized by the following molecular structure compared to the raw material polysilazane. (i) The proportion of nitrogen atoms bonded to silicon atoms increases. As described above, the copolymerized silazane of claim (2) contains a new crosslinking group, and the proportion of nitrogen atoms based on this crosslinking group increases. The ratio of nitrogen atoms bonded to silicon atoms to silicon atoms in the copolymerized silazane of claim (2) (N/
The upper limit of Si) is defined within a range in which gelation of the copolymerized silazane does not occur, in other words, within a range that shows solvent solubility, and is usually 2.5 or less, preferably 2.0 or less. . (ii) Number average molecule i range is 200-500,00
0 There is. The copolymerized silazane of claim (2) uses polysilazane having a number average molecular weight of 100 to 50,000 as a raw material as described above, and at least one type selected from ammonia, primary amines, hydrazine, and substituted hydrazine. Since it is formed by crosslinking and polymerizing using polysilazane as a crosslinking agent, its molecular weight is naturally higher than that of the raw material polysilazane. - For boat fishing, the copolymerized silazane targeted by the present invention has a number average molecular weight of 200 to 500,000, preferably 1500 to 500,000.
It has 10000. The copolymerized silazane of claim (2) has the above-mentioned characteristics in terms of molecular structure and is distinguished from the raw material polysilazane, but another characteristic is that it has many branched structures. There is one. Because of this branched structure, the claim (
Although the copolymerized silazane of 2) has a higher molecular weight than the raw material polysilazane, it provides results with improved solvent solubility. The inorganic silazane proposed by 5eyferth et al. is an oily liquid with a proton ratio of 5i-H/N-)1 of about 3.3, and is heated at about 200'C, but left at room temperature for 3 to 5 days. It is solidified by On the other hand, the copolymerized silazane of claim (2) has a molecular weight of 200 to 5oooooo, contains the above-mentioned new crosslinking group, and has a ratio of nitrogen atoms to silicon atoms (N/Si) that is higher than that of the raw material polysilazane. It has high solvent resolubility. The reason why the copolymerized silazane of claim (2) has a more branched structure than the raw material polysilazane is that in the polycondensation reaction of the present invention, in addition to the polycondensation reaction, a disproportionation reaction of polysilazane, etc. This is thought to be due to what happens. The copolymerized silazane of claim (2) has the above-mentioned molecular structural characteristics, and has a new crosslinking bond in terms of physical properties, but is soluble in organic solvents in most cases, and is particularly suitable for the copolymerized silazane. The solid polymer obtained by removing the solvent from the silazane solution exhibits a significant feature of being re-soluble in the solvent. In the case of conventional polysilazane, stability is poor and when the solvent is removed from the solution, a resinous solid is produced, which is insoluble in the solvent, but the copolymerized silazane of claim (2) does not have this tendency. does not indicate. Therefore, in the case of conventional polysilazane, it was impossible or extremely difficult to handle it as a solid polymer. The copolymerized silazane of claim (2) can be easily handled as a solid polymer. [Effects of the Invention] Since the copolymerized silazane of the present invention has the above-described structure, it exhibits the following effects. In the copolymerized silazane of claim (1), (1) the copolymerized silazane is soluble in organic solvents and can be converted into silicon nitride or silicon nitride-containing ceramics by firing; High strength, heat resistance, corrosion resistance, oxidation resistance, heat resistance? # Continuous fibers, films, and coatings with excellent impact resistance can be easily obtained. Also,
Since the ceramic yield is high, it can also be used as a binder for sintering, an impregnating agent, etc. ■ Copolymerized silazane does not contain impurities such as residual catalyst that promotes decomposition in the polymer. Improved stability
It is easier to handle and also improves the purity of ceramics after high-temperature firing. Copolymerized silazane has a higher molecular weight than the raw material inorganic and organic polysilazane, so it has improved solidification and can be quickly processed at room temperature. (1) Due to its high molecular weight, evaporation loss during high-temperature firing is small, improving ceramic yield. ■Since there is no contamination of impurities, the purity of ceramics after high-temperature firing is improved. ■When spinning copolymerized silazane, continuous spinning is possible without adding a spinning aid. ■Blocks in copolymerized silazane By changing the ratio of 8 and block B, it is possible to obtain any electrical property of the ceramic after high-temperature firing, from an insulator to a semiconductor.Also, by being able to control the amount of SiC produced in the same way, The far-infrared effect can be changed continuously. ■The crystallization temperature of ceramics after high-temperature firing is high. In the copolymerized silazane according to claim (2), by having the crosslinking bond. (2) Further, it becomes easier to increase the molecular weight of the copolymerized silazane. (2) Further, the solvent solubility is improved. In addition, in the method for producing copolymerized silazane according to claim (3), (1) no catalyst such as a transition metal is used, so there is no need for a separation step between the product and the catalyst, and (2) the catalyst remains in the copolymerized silazane. ∎Low cost and safety as no expensive and dangerous catalysts are used; ∎High molecular weight due to copolymerization. (1) The carbon content of the ceramics after high-temperature firing can be controlled over a wide range; (2) Since it is copolymerization, the elemental composition of the ceramics after high-temperature firing can be controlled. In the production method of claim (4), (1) it is also easier to increase the molecular weight of the copolymerized silazane; [Example] Hereinafter, the present invention will be explained in more detail with reference to Examples. Reference Example 1 A four-loop flask with an internal volume of 1Ω was equipped with a gas blowing tube, a mechanical stirrer, and a dewar condenser. After the inside of the reactor was replaced with deoxygenated dry nitrogen, degassed dry pyridine 490- was placed in a four-bottle flask and cooled on ice. Next, when 51.6 g of dichlorosilane was added, a white solid adduct (SiH2CQ2.2C,H,N) was formed.
was generated. The reaction mixture was ice-cooled, and while stirring, 51.0 g of purified ammonia was blown into the reaction mixture 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 further filtered under nitrogen atmosphere to obtain filtrate 8.
I got 50 results. The solvent was distilled off from the filtrate 5- under reduced pressure to obtain 0.102 g of resin solid perhydropolysilazane. The number average molecular weight of the obtained polymer was 980 as measured by GPC. Also, the IR of this polymer
Examining the (infrared absorption) spectrum (I medium: dry 0-xylene; concentration of perhydropolysilazane: 10.2 g/Q), the wave number (cm-L) is 3350 (apparent extinction coefficient t = 0.557 Qg-1 cm) -1) and NH-based absorption of 1175; SLH of 2170 (ε=3.14)
Absorption based on SiH and Si of 1020-820
It was confirmed that the material exhibits absorption based on N Si. Further, when examining the 1HNMR (Prone Nuclear Magnetic Resonance) spectrum (60 MHz, solvent CDCQ3/reference material TMS) of this polymer, it was confirmed that all of them exhibited broad absorption. That is, 64.8 and 4.4 (br, 5
Absorption of iH); 1.4 (br. NH) was confirmed. Reference Example 2 A reaction was carried out using the same apparatus as Reference Example 1. That is, 500 g of degassed dry dichloromethane was placed in the four-loaf flask shown in Reference Example 1, and cooled with water. Next, 48.6 g of dichlorosilane was added. This solution was cooled with water, and while stirring, 42.5 g of purified ammonia was blown into the solution as a mixed gas with nitrogen through a sodium hydroxide tube and an activated carbon tube. During the reaction, powder mist was generated in the gas flow path, so the gas flow path was occasionally tapped to prevent clogging. The reaction mixture was treated in the same manner as in Reference Example 1 to obtain 9.6 g of viscous oily perhydropolysilazane. The number average molecular weight of the obtained polymer was 640 as measured by GPC.
Met. Reference Example 3 A reaction was carried out using the same apparatus as Reference Example 1. That is, 450 ml of degassed dry tetrahydrofuran was placed in the four-loaf flask shown in Reference Example 1, and cooled in a dry ice-methanol bath. Next, 46.2 dichlorosilane were added. This solution was cooled, and 44.2 g of anhydrous methylamine was blown into the solution as a mixed gas with nitrogen while stirring. After the reaction was completed, the reaction mixture was centrifuged, washed with dry tetrahydrofuran, and then filtered under a nitrogen atmosphere to obtain filtrate 820-. When the solvent was distilled off under reduced pressure, 8.4 g of viscous oily N-methylsilazane was obtained. The number average molecular weight of the obtained polymer was 1100 as measured by GPC. Reference Example 4 A four-loop flask with an internal volume of IQ was equipped with a gas blowing pipe, a mechanical stirrer, and a dewar condenser. After purging the inside of the reactor with deoxygenated dry nitrogen, 300 mQ of dry dichloromethane and 24.3 g (0,211 mou) of methyldichlorosilane were placed in a four-bottle flask.
Water cooled. 18.1 g (1,06 m
oQ) was injected. After the reaction was completed, the reactor mixture was centrifuged, washed with dry dichloromethane, and filtered under a nitrogen atmosphere. When the solvent was distilled off from the filtrate under reduced pressure, 8.81 g of a colorless and transparent liquid was obtained.
Obtained. The number average molecular weight of this product was 380 as measured by GPC. Reference Example 5 A reaction was carried out using the same apparatus as Reference Example 1. That is, 450 g of degassed dry benzene was placed in the four-loaf flask shown in Reference Example 1, and cooled on ice. Next, 40.6 g of dichlorosilane was added. This solution was cooled with water, and while stirring, 42.0 g of purified ammonia was blown into the solution as a mixed gas with nitrogen through a sodium hydroxide tube and an activated carbon tube. During the reaction, powder mist was generated in the gas flow path, so the gas flow path was occasionally tapped to prevent clogging. The reaction mixture was treated in the same manner as in Reference Example 1 to obtain 5.2 g of viscous oily perhydropolysilazane. The number average molecular weight of the obtained polymer was determined to be 81 by GPC and was 320. Reference Example 6 A mechanical stirrer and a dewar condenser were used to drip the liquid into a four-loaf flask with an internal volume of IQ. After replacing the interior of the reactor with deoxygenated dry nitrogen, 400% of degassed dry benzene was placed in a four-bottle flask using a known method (J,
Am, Chem, Soc,, Vol, 67.1813 (
Allyldichlorosilane 64.
Add 5g of the liquid and add one drop to the stirred funnel using a known method (J
,A+o,Che+a,Soc, ,Vol,70.4
35 (1948)) and 50 g of dry benzene were added. A benzene solution of triethylaminosilane was added dropwise to a benzene solution of allyldichlorosilane. After the dropwise addition was completed, the mixture was heated to reflux in an oil bath while stirring to carry out the reaction. After the reaction was completed, the reaction mixture was centrifuged, washed with dry benzene, and further filtered under a nitrogen atmosphere to obtain filtrate 680-. When the solvent is removed from the filtrate, liquid N-(
19.2 g of triethylsilyl)allylsilazane was obtained. The number average molecular weight of the obtained polymer was 360 as measured by GPC. Reference Example 7 Grignard reagent synthesized from cyclohexyl bromide 62. Og was slowly added to 110 g of trichlorosilane. Distillation under reduced pressure yielded 16.4 g of cyclohexyldichlorosilane. The same apparatus as in Reference Example 6 was used. 12.0 g of cyclohexyldichlorosilane and 420 g of dry benzene were placed in a four-bottle flask and stirred. 15.6 g of 1,1-dimethylhydrazine in the dropping funnel
and 40% of dry benzene. A benzene solution of 1,1-dimethylhydrazine was added dropwise to a benzene solution of cyclohexyldiglorosilane. After the dropwise addition was completed, the reaction was carried out at room temperature with stirring. After the reaction was completed, the reaction mixture was centrifuged, washed with dry benzene, and further filtered under a nitrogen atmosphere to obtain 730 ml of filtrate. When the solvent was removed from the filtrate, 3.2 g of oily N-(dimethylamino)cyclohexylsilazane was obtained. The number average molecular weight of the obtained polymer was 390 as measured by GPC. Reference Example 8 A reaction was carried out using the same apparatus as in Reference Example 1. That is, 500 mQ of degassed dry toluene was placed in the four-loaf flask shown in Reference Example 1 and cooled on ice. Next, phenyldichlorosilane 52. ], g was added. This solution was ice-cooled, and while stirring, 30.0 g of purified ammonia was blown into the solution as a mixed gas with nitrogen through a sodium hydroxide tube and an activated carbon tube. The reaction mixture was treated in the same manner as in Reference Example 1 to obtain 6.8 g of oily phenylpolysilazane. The number average molecular weight of the obtained polymer was 380 as measured by GPC. Example 1 To 70 cc of the pyridine solution of perhydropolysilazane obtained in Reference Example 1 (4.OOg of perhydropolysilazane) was added 1.93 g of methylsilazane obtained in Reference Example 4,
The mixture was placed in a pressure-resistant reaction vessel having an internal volume of 300 m12, 8.7 g (0,512 mol) of purified anhydrous ammonia was added, and the reaction was carried out in a closed system at 120° C. with stirring for 3 hours. During this time, a large amount of gas was generated. The pressure before and after the reaction is 1.
Increased by 1 kg/d. This gas was determined to be hydrogen by gas chromatography (GC) measurements. After cooling to room temperature, add 200% of dry 0-xylene to a pressure of 3-5 mmH.
g, when the solvent was removed at a temperature of 50 to 70°C, 5.34
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 was 1790 as measured by GPC. In addition, as a result of analysis of its IR spectrum (solvent: 0-xylene), the wave number (cm-"
) 3350 and 1175 NH-based absorption; 217
Absorption based on SiH of 0; 5i)l of 1020-820
and absorption based on 5iNSi; 2980.2950.2
It was confirmed that absorption based on CH 880.1270 was exhibited. Furthermore, when the 18 NMR spectrum (CDCI2., TMS) of the polymer powder was analyzed, all of them showed broad absorption. That is, δ4.8(br, Si
H,), δ4.4 (brkSiHa) −δ), 4
(br,NH), δ0.3(br,5iC)I, ) absorption was observed. In addition, the elemental analysis results of the polymer powder are (weight'1) S
i: 57.1%, N: 27.1%, O: 4.17%, C
Near, it was 30%. Example 2 80 cc of pyridine solution of perhydropolysilazane obtained in Reference Example 5 (perhydropolysilazane 1.60.)
Add 1.50 g of N-methylsilazane obtained in Reference Example 3 and 0.95 E of methylsilazane obtained in Reference Example 4,
The mixture was placed in a pressure-resistant reaction vessel having an internal volume of 300 mL, and 4.2 g (0,247 mol) of purified anhydrous ammonia was added thereto, and the reaction was carried out in a closed system at 130° C. with stirring for 3 hours. During this time, a large amount of gas was generated, which was determined to be hydrogen by GC measurement. The pressure increase before and after the reaction is 1゜4kg.
/cd. When the solvent was distilled off under reduced pressure in the same manner as in Example 1, 3.24 g of white powder was obtained. The number average molecular weight of the polymer powder was 2030 as measured by GPC. Furthermore, as a result of the analysis of the IR spectrum (solvent 20-xylene), the wave number (am-”) was 33.
Absorption based on NH of 50 and 1175; Si of 2170
Absorption based on H; 1020-820 SiH and 5iN
Absorption based on Si: It was confirmed that absorption based on C)I of 2940.2900.2820 and 1270 was exhibited. Furthermore, the iHNMR spectrum (CDC
As a result of analyzing δ4, 8 (br
. SiH, ), δ4,4 (br, 5Ji), δ1.4 (b
r, NH), δ2.6 (br, NCH++), δ0.3
Absorption of (br, 5iclI,) was observed. Example 3 100 cc of γ-picoline solution of perhydropolysilazane obtained in Reference Example 1 (perhydropolysilazane 4°44
1.48 g of N-(dimethylamino)-cyclohexylsilazane obtained in Reference Example 7 was added to g), placed in a pressure-resistant reaction vessel with an internal volume of 300, and anhydrous ammonia 5 manufactured by M was added.
, 7g (0,335mol) was added in a closed system to 150
The reaction was carried out with stirring at .degree. C. for 5 hours. A large amount of gas was generated during this time, and GC measurements showed that this gas was hydrogen. The pressure before and after the reaction is 0.9 kg/a.
It was +f. When the solvent was distilled off under reduced pressure in the same manner as in Example 1, 4.14 g of yellow rubbery solid was obtained. The number average molecular weight of the polymer was determined to be 1730 by GPC. Example 4 100 cc of pyridine solution of perhydropolysilazane obtained in Reference Example 1 (3.21 g of perhydropolysilazane)
2.02 g of N-(triethylsilyl)-allylsilazane obtained in Reference Example 6 was added to the mixture, and the mixture was placed in a pressure-resistant reaction vessel with an internal volume of 300 mm, and 4.8 g of purified anhydrous ammonia (0,
282 mol) was added thereto, and the reaction was carried out in a closed system at 150° C. with stirring for 6 hours. A large amount of gas was generated during this time, and GC measurements showed that this gas was hydrogen. The pressure increase before and after the reaction was 1.0 kg/a+t. When the solvent was distilled off under reduced pressure in the same manner as in Example 1, 3.54 g of a yellow rubbery solid was obtained. The number average molecular weight of the polymer was 1880 as measured by GPC. Example 5 100 cc of pyridine solution of perhydropolysilazane obtained in Reference Example 2 (4.62 g of perhydropolysilazane)
1.21 g of phenylsilazane obtained in Reference Example 8 was added to the mixture, and the mixture was placed in a pressure-resistant reaction vessel with an internal volume of 300 m12, and 8.9 g (0,278 mol) of anhydrous hydrazine was added thereto, followed by stirring at 100°C for 3 hours in a closed system. The reaction was carried out while During this time, a gas was generated, which was determined to be hydrogen by GC measurement. The pressure increase before and after the reaction is 1.2
kg/d. When the solvent was distilled off under reduced pressure in the same manner as in Example 1, 3.79 g of white powder was obtained. The number average molecular weight of the polymer was 2250 as measured by GPC. Example 6 Reference Example 4 was added to 80 cc (4.31 g of N-methylsilazane) of the pyridine solution of N-methylsilazane obtained in Reference Example 3.
Add 2.02 g of methylsilazane obtained in
00- in a pressure-resistant reaction vessel, anhydrous ethylhydrazine 2
Add 5g (0,416mol) and heat to 120"C in a closed system.
The reaction was carried out with stirring for 6 hours. A large amount of gas was generated during this time, but was it GC? lI! According to I, this gas was hydrogen. The pressure increase before and after the reaction is 1.0 kg.
/aJ. When the solvent was distilled off under reduced pressure in the same manner as in Example 1, 4.30 g of white powder was obtained. The number average molecular weight of the polymer was 2130 as measured by GPC. Example 7 100 cc of pyridine solution of perhydropolysilazane obtained in Reference Example 1 (2.47 g of perhydropolysilazane)
3.24 g of N-methylsilazane obtained in Reference Example 3 was added to the mixture, and the mixture was placed in a pressure-resistant reaction vessel with an internal volume of 300 mm, and 7.4 g (0.101 mol) of n-butylamine was added thereto, and the mixture was heated at 140°C in a closed system. The reaction was carried out with stirring for 6 hours. During this time, a large amount of gas was generated, but GC measurements showed that this gas was hydrogen. The pressure increase before and after the reaction is 0.9k
g/cn? Met. When the solvent was distilled off under reduced pressure in the same manner as in Example 1, 3.94 g of pale yellow rubbery solid was obtained. The number average molecular weight of the polymer was determined to be 1850 by GPC. Example 8 100 cc of pyridine solution of perhydropolysilazane obtained in Reference Example 2 (3.70 g of perhydropolysilazane)
1.62 g of methylsilazane obtained in Reference Example 4 was added to the mixture, placed in a pressure-resistant reaction vessel with an internal volume of 300 -, and 15 g (0,250 mol) of 1-dimethylhydrazine was added.
The reaction was carried out at 1.20'C for 4 hours with stirring. During this time, a large amount of gas was generated, which was determined to be hydrogen by Gcg determination. The pressure increase before and after the reaction is 1.
0kg/co! Met. When the solvent was distilled off under reduced pressure in the same manner as in Example 1, 3.19 g of white powder was obtained. The number average molecular weight of the polymer was measured by GPC and was 2160. Example 9 The copolymerized silazane obtained in Example 1 was heated to 1500 ml in nitrogen.
The mixture was heated to 3° C./min and thermally decomposed to obtain a gray-black solid in a yield of 88.6% by weight. When the obtained ceramic was subjected to powder X-ray diffraction measurement, it was confirmed that it was amorphous. Next, this solid was further heated and calcined in nitrogen at a heating rate of 10° C./min to 1700° C. to obtain a black-green solid. Powder X-ray diffraction measurements of this substance revealed that 2θ=
α-3i at 20.5', (101) diffraction line of N4, 2
(110) diffraction line of α-813N4 at θ, 22.9′,
(200) diffraction line of α-3i3N. at 2θ=26.4″; α-3i at 2θ=30.9″’;
(201) diffraction line of N4, 2 B = 31.7' I
c a-513N4(7) (002) diffraction line, 2o=3
4-5' Ic α-313N-(71(102) Diffraction k, 2 B = 35.2° Ni α-5i, N,
10) Diffraction line, 2θ=38.8° of α-3i3N4 (
211) Diffraction line, α-8i3N at 2θ=39.4@, (112) diffraction line, α-5i3N at 2θ=4.0.1'
, (300) diffraction line, 2θ=41.8″l: α-3
i3N, (7) (202) Diffraction AI! , 2θ=43.
(301) diffraction line of 4'4Ca-5L3N, 2θ=4
(220) diffraction line of α-5i3N4 at 6.9°, 2θ=
(212) diffraction line of α-3i3N at 48.2°, 2θ
The (310) diffraction line of α-3i3N at =48.8°, and the (110) diffraction line of β-3i, N, at 2θ=23.3''
Diffraction line, β-5i3N4 (20
0) Diffraction line, (1
01) Diffraction line, 20 = 36.0' β-3i, N,
(210) diffraction line, β-5i at 2θ=41.4”,
(201) diffraction line of N4, β-Si at 2θ = 49.9'
, N, (310) diffraction line, α at 20 = 34.2°
-5iC (101) diffraction line, α- at 2θ=35°7°
5iC (006) diffraction line, (102) diffraction line, 2θ=
(103) diffraction line of α-3iC at 38.2°, 20 =
α-5iC (104) diffraction line was observed at 41.5″,
It was confirmed that it was a crystalline silicon nitride-silicon carbide mixed ceramic. Elemental analysis results of this crystalline mixed ceramic (weight%)
) Si: 64.4, N:, 26.0, O: 2.2, C:
It was 6.8.

[1 other person]

Claims (4)

[Claims] (1) Inorganic polysilazane part A with a number average molecular weight of 100 to 50,000 and a number average molecular weight of 100 to 50,000
The number average molecular weight consisting of organic polysilazane moiety B is 2
00 to 500,000 block copolymerized silazane, A is mainly a formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼
It has a skeleton represented by the following formula, and B is mainly represented by the formula
A block copolymerized silazane characterized by being a polysilazane block having a skeleton represented by ▼. (In the formula, R^1 and R^2 are a hydrogen atom, an alkyl group that may have a substituent, an alkenyl group, a cycloalkyl group, an alkylamino group, an aryl group, an aralkyl group, or an alkylsilyl group, shown respectively. However, R^1 and R
Except when both ^2 are hydrogen atoms. ) (2) The block copolymerized silazane according to claim (1), wherein at least one type of crosslinking bond represented by the following general formulas (I) to (VI) is present between at least the polysilazane moieties A and B. (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(▲Mathematical formulas,
There are chemical formulas, tables, etc. ▼ is an ammonia residue) (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ is a primary amine residue) (III) ▲ Mathematical formula, There are chemical formulas, tables, etc.▼(▲Mathematical formulas,
There are chemical formulas, tables, etc. ▼ is a hydrazine residue) (IV) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ is a 1-substituted hydrazine residue) (V) ▲ Mathematical formula, There are chemical formulas, tables, etc. ▼ (▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ is a 1,2-substituted hydrazine residue) (VI) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ is a 1,1-substituted hydrazine residue) (In the formula, R^3 and R^4 are an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, an aralkyl group, which may have a substituent, or (Heterocyclic groups are shown respectively.) (3) An inorganic polysilazane with a skeleton represented by the formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼ and a number average molecular weight of 100 to 50,000, and an inorganic polysilazane that is represented by the formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼ Has a skeleton and has a number average molecular weight of 100~
50,000 of organic polysilazane under basic conditions. (In the formula, R^1 and R^2 are a hydrogen atom, an alkyl group that may have a substituent, an alkenyl group, a cycloalkyl group, an alkylamino group, an aryl group, an aralkyl group, or an alkylsilyl group, shown respectively. However, R^1 and R
Except when both ^2 are hydrogen atoms. ) (4) An inorganic polysilazane having a skeleton represented by the formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ and a number average molecular weight of 100 to 50,000, and an inorganic polysilazane represented by the formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ Has a skeleton and has a number average molecular weight of 100~
50,000 organic polysilazane, ammonia,
3. The method for producing a block copolymerized silazane according to claim 2, wherein at least one selected from a primary amine, hydrazine, and substituted hydrazine is reacted under basic conditions. (In the formula, R^1 and R^2 are a hydrogen atom, an alkyl group that may have a substituent, an alkenyl group, a cycloalkyl group, an alkylamino group, an aryl group, an aralkyl group, or an alkylsilyl group, shown respectively. However, R^1 and R
Except when both ^2 are hydrogen atoms. )