JPH0686525B2 - Method for producing silicon-containing polycyclic aromatic polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an inorganic fiber excellent in mechanical properties, oxidation resistance and compatibility with a matrix for composite materials, mechanical properties,
The present invention relates to a method for producing a precursor polymer suitable for producing a matrix for a composite material, a molded body, etc., which are excellent in oxidation resistance, abrasion resistance, heat resistance and the like.

(Prior art and its problems) Since carbon fiber is lightweight, yet has high strength and high elasticity,
It is used in a wide range of fields such as sports / leisure goods, aircraft, bicycles, and building materials.

Known carbon fibers include PAN-based carbon fibers made from polyacrylonitrile and so-called pitch-based carbon fibers made from petroleum-based and coal-based pitches.

Pitch-based carbon fibers are generally inferior in strength to PAN-based carbon fibers, but since the raw material is inexpensive, various studies have been made on methods for increasing the strength, for example, JP-A-59-22331.
Japanese Unexamined Patent Publication (Kokai) No. 6 discloses a method in which mesophase is effectively generated and oriented during spinning.

However, since carbon fibers are basically crystalline fibers, they have the drawbacks that they are hard and easily fluffy, and that they are inferior in wettability with the matrix when they are used as a composite material.

Therefore, various surface treatment methods for carbon fibers have been proposed, and currently known methods include polyvinyl alcohol, unsaturated polyester resin, and epoxy resin for the purpose of imparting flexibility to the fiber and suppressing fuzz formation. There is a method of applying a different sizing agent to the surface, a method of oxidizing the surface by a dry method or a wet method for the purpose of improving the adhesiveness with the matrix.

Among these treatments, in particular, the method of providing the surface oxidation layer tends to deteriorate the physical properties because the fibers are damaged during the oxidation. Furthermore, carbon fibers cannot be used because they burn in an oxidizing atmosphere exceeding 500 ° C.

Against this background, we have developed a new fiber that has high strength, high elastic modulus, good wettability with the matrix, and good adhesion, and is cheaper than the PAN-based carbon fiber that has been used in a wide range of conventional fields. Has been strongly requested.

Further, it is strongly desired in various fields to improve the oxidation resistance of carbon fibers at higher temperatures.

On the other hand, so-called C / C composites and carbon moldings that use carbon fiber as a reinforcing fiber and carbon as an inorganic matrix are excellent in specific strength, specific elasticity, heat resistance in a non-oxidizing atmosphere, toughness, friction characteristics, and heat resistance. It is a promising material for structural materials and brake materials.

However, since the matrix of C / C composites and carbon moldings consists only of carbon, it is difficult to use them for a long time in an oxidizing atmosphere. Wearability is not always sufficient, and further improvement in mechanical properties is expected.

As a method of solving the problem in the fiber, for example, JP-A-62-209139, JP-A-62-215016, mixing organic solvent-soluble components in coal-based or petroleum-based pitch and polysilane. -A method for producing an inorganic fiber having an intermediate property between silicon carbide fiber and carbon fiber by heating, synthesizing organopolyarylsilane and spinning, infusibilizing, and firing it is described.

However, in the above method, a pitch containing no organic solvent insoluble matter is selected as one of the starting materials, and the reaction is carried out under the condition that the insoluble matter is not produced even in the production of organopolyarylsilane.

That is, the spinning raw material that is the obtained product does not contain an orientation component that is essential for developing the strength of the carbon fiber, and no highly elastic inorganic fiber is obtained from the spinning raw material.

Further, in the method of the above-mentioned publication, as the pitch component increases, the heat resistance of the inert gas is improved, but on the contrary, the oxidation resistance is lowered, and further, the mechanical properties are remarkably lowered.

In addition, as a method for compensating for the essential drawbacks of the carbon matrix, in Walker (JW), Am. Ceram. Soc. Bull. 62 (1983) 916, C / C composite was impregnated with an organosilicon polymer. After that, a method of thermally decomposing and introducing a carbon-silicon component into the matrix is described, but the bending strength of the obtained composite material is as low as 158 MP.

Also, Proc.of Int.Symp.on.Ceramic, Compon.for Engin
e, 1983, Japan, p505, Fittour (E.Fitze
r) et al. describe a method of impregnating a C / C composite with a silicon melt to convert the matrix into silicon carbide, but the obtained composite material remains unreacted between the matrix particles. Because of the metallic silicon, which undergoes creep metamorphism at high temperatures above 1300 ° C, it does not have the high-temperature characteristics of C / C composites.

In any of the above processes, in addition to the conventional complicated C / C composite manufacturing process, a more complicated process was added, which made industrial use difficult.

Therefore, there is a strong demand for the development of a precursor polymer that can be easily converted into an excellent carbonaceous inorganic fiber or a matrix for a composite material by mineralization.

(Means for Solving Problems) An object of the present invention is to solve the above problems and to have the characteristic of high elasticity of pitch fibers, and to have excellent strength, oxidation resistance, and wettability to a composite material matrix. It is to provide a method for producing a precursor polymer of carbon-based inorganic fibers.

Another object of the present invention is to provide a method for producing a precursor polymer suitable for producing a matrix for a composite material, a molded body and the like which are excellent in mechanical properties, oxidation resistance, heat resistance and the like.

According to the present invention, i) a bond unit (Si-CH ₂ ), or a bond unit (Si-CH ₂ ) and a bond unit (Si-Si) is mainly contained, and a hydrogen atom or a lower alkyl group is present in the side chain of the silicon atom. , Having a substituent selected from the group consisting of a phenyl group and a silyl group, the ratio of the total number of bond units (Si-CH ₂ ) to the total number of bond units (Si-Si) is in the range of 1: 0 to 20. At least a part of the silicon element of the organosilicon polymer is a petroleum-based or coal-based pitch or a heat-treated product thereof, and the aromatic of the polycyclic aromatic compound obtained from the pitch from which the soluble matter in the organic solvent has been removed 100 parts by weight of a random copolymer bonded to ring carbon, and ii) a mesophase or a mesophase and an optically isotropic phase obtained by further heat-treating an organic solvent-insoluble component in a petroleum-based or coal-based pitch or a heat-treated product thereof. And a polycyclic aromatic compound consisting of both phases (hereinafter, May be collectively referred to as "mesophase polycyclic aromatic polymer". 5 to 900 parts by weight are heated and / or melted at a temperature in the range of 200 to 500 ° C. A method for producing a silicon-containing polycyclic aromatic polymer is provided.

First, the silicon-containing polycyclic aromatic polymer of the present invention will be described. In the following description, all "parts" are "parts by weight" and all percentages (%) as a unit of component content are "% by weight".

The silicon-containing polycyclic aromatic polymer of the present invention comprises the constituent components (A), (B) and (C), and at least a part of the silicon atoms of the constituent component (A) is the constituent component (B) and / or Alternatively, it is bonded to a carbon atom of the aromatic ring of the component (C). The weight ratio of the component (A) to the sum of the component (B) and the component (C) is 1: 0.5 to 200, and the weight ratio of the component (B) to the component (C) is 1. : 0.02-4
Is preferred.

If the weight ratio of the component (A) to the sum of the component (B) and the component (C) is less than 0.5, the orientation component in the silicon-containing polycyclic aromatic polymer will be insufficient, and for example, Even if the inorganic fiber is manufactured from the coalescence, only those having low strength and low elastic modulus can be obtained. Further, when the above ratio exceeds 200, the oxidation resistance of the inorganic compound of this polymer decreases due to the lack of the organosilicon component in the silicon-containing polycyclic aromatic polymer,
The wettability with plastic etc. becomes low.

If the weight ratio of (C) to (B) is less than 0.02, the silicon-containing polycyclic aromatic polymer has a high melting point and a high softening point, resulting in poor fluidity and inconvenience in molding. For example, even if melt spinning is attempted using this polymer, spinning becomes extremely difficult, such as a decrease in spinnability and a breakage due to uneven viscosity of the dope. If the above ratio exceeds 4,
Due to the lack of the mesophase component in the silicon-containing polycyclic aromatic polymer, the inorganic compound obtained from the polymer has low strength and low elastic modulus.

The silicon-containing polycyclic aromatic polymer of the present invention has a silicon atom of 0.
Contains 25 to 30% and weight average molecular weight of 200 to 11000
And the melting point is 180-350 ° C.

The silicon atom content in the silicon-containing polycyclic aromatic polymer is 0.25.
If it is less than%, the amount of the amorphous phase composed of Si, C, and O or the β-SiC ultrafine particles in the inorganic compound of the polymer is too small, so that, for example, the wettability to the FRP matrix and the oxidation resistance are significantly improved. If the amount exceeds 30%, it is not possible to achieve high elasticity in a non-oxidizing atmosphere with high elasticity due to the orientation of the ultrafine graphite particles in the above-mentioned inorganic material.

A silicon-containing polycyclic aromatic polymer having a weight average molecular weight of less than 200 cannot provide a high-performance inorganic fiber, composite material, or molded article because it contains substantially no orienting component, and is more than 11000. If it is large, the melting point becomes high, and it becomes difficult to form an arbitrary shape having poor fluidity.

When the melting point of the silicon-containing polycyclic aromatic polymer is lower than 180 ° C, it does not substantially contain mesophase, and when this polymer is spun to produce an inorganic fiber, the precursor yarn is fused during infusibilization. It is difficult to obtain a fired yarn having high strength and elastic modulus. On the other hand, if the melting point of the polymer is higher than 350 ° C., the softening / flowing temperature becomes high, which is not preferable.

Further, the silicon-containing polycyclic aromatic polymer contains 10 to 98% insoluble matter in an organic solvent such as benzene, toluene, xylene, and tetrahydrofuran, and has a chemical anisotropy degree of 5 to 97% at room temperature. Is preferred.

If the content of the silicon-containing polycyclic aromatic polymer insoluble in the above organic solvent is less than 10% or the degree of optical anisotropy is less than 5%,
Even if the polymer is melt-molded and made inorganic, there is almost no mesophase orientation, and inorganic fibers, molded products, composite materials, etc. having excellent mechanical properties cannot be obtained. Further, when the content of the insoluble matter in the organic solvent is more than 98% or the optical anisotropy degree is more than 97%, the mesophase in the polymer becomes excessive, which makes spinning and molding of the polymer difficult. Become.

Since the silicon-containing polycyclic aromatic polymer of the present invention is melted by heating, it is preferably used as a precursor of inorganic fibers, for example.

Next, a method for producing the silicon-containing polycyclic aromatic polymer of the present invention will be described.

The organosilicon polymer, which is one of the starting materials, can be synthesized by a known method. For example, polydimethylsilane obtained by the reaction of dimethyldichlorosilane and metallic sodium is heated to 40 ° C. or higher in an inert gas. It is obtained by doing.

The organosilicon polymer, binding unit (Si-CH _2), or binding units (Si-Si) and mainly consists binding units (Si-CH _2), the total number pairing unit of coupling units (Si-CH ₂₎ The ratio of the total number of (Si-Si) is in the range of 1: 0 to 20.

The weight average molecular weight of the organosilicon polymer is generally 300 to 1
000, especially 400 to 800, is preferable for adjusting the random copolymer (2) which is an intermediate raw material for obtaining excellent inorganic fibers, composite materials, molded bodies and the like.

Another starting material, polycyclic aromatic compounds, are pitches obtained by removing soft fractions from fluid catalytic cracking residual oil (FCC slurry oil) of petroleum or its pyrolysis oil, and pitch obtained from naphthatar. , And an insoluble component in at least one organic solvent selected from benzene, toluene, xylene, and tetrahydrofuran in coal-based pitch such as coal tar pitch (hereinafter, the insoluble component in this organic solvent is referred to as “organic solvent insoluble component (1) It is suitable to use).

The pitch used for obtaining the organic solvent insoluble matter (1) preferably has an insoluble content in the organic solvent of 98% or less. The fact that the pitch contains an organic solvent insoluble content of more than 98% indicates that the cyclization has progressed to a state close to coke itself, and the pitch and its organic solvent washing residue are shown. Is difficult to copolymerize with the organosilicon polymer, and the product partially containing the copolymer also has a high melting point (300 ° C. or higher) and is non-uniform.

The random copolymer (2) is preferably prepared by adding the organic melt insoluble matter (1) to an organic silicon polymer, and preferably adding it in an inert gas at 25
It is prepared by reacting by heating at a temperature of 0 to 500 ° C.

The proportion of the organic solvent insoluble component (1) used is 10% by weight of the organosilicon polymer.
It is preferably 83-1900 parts per 0 part. When the proportion of the organic solvent insoluble component (1) used is transiently low, the amount of the organic silicon component increases, the compatibility with the mesophase polycyclic aromatic compound deteriorates, and the uniformity during melting is impaired.
When a fiber or a molded product is manufactured, the elastic modulus decreases. If the ratio is excessively high, the amount of the organosilicon polymer component is too small, and the compatibility with the matrix and the oxidation resistance of the composite material produced from the polymer of the present invention are deteriorated.

When the reaction temperature of the above reaction is transiently low, a bond between a silicon atom and an aromatic carbon is hard to be generated, and when the reaction temperature is transiently high, the generated random copolymer (1) is decomposed and becomes high in molecular weight. It does not happen.

Nitrogen, argon and the like are preferably used as the inert gas.

The mesophase polycyclic aromatic compound (3) can be prepared by heating the organic solvent-insoluble matter (1) to 300 to 500 ° C. in an inert gas and polycondensing while removing the produced soft fraction. it can.

The mesophase polycyclic aromatic compound (3) generally has a melting point in the range of 200 to 350 ° C and a weight average molecular weight of 20.
0 to 8000.

Among the mesophase polycyclic aromatic compounds (3), 20-
What has 100% of optical anisotropy and contains 2 to 30% of quinoline insoluble matter is particularly preferable for obtaining a polymer as a raw material for inorganic fibers.

The advantage of removing the organic solvent-soluble component in the pitch is that the copolymerization of the polycyclic aromatic compound and the organosilicon compound in the pitch, and the component inhibiting the mesophase formation of the pitch are eliminated, whereby the copolymerization and the mesophase formation are prevented. It is possible to complete the reaction under mild conditions, and thus to suppress the formation of an excessively high molecular weight condensate. In particular, regarding the mesophase polycyclic aromatic compound (3), it is possible to obtain a compound having a high optical anisotropy, a low melting point, and a low quinoline insoluble content.

The random copolymer (2) heat-reacts and / or heat-melts the mesophase polycyclic aromatic compound (3) at 200 to 500 ° C. to obtain a silicon-containing polycyclic aromatic polymer.

The proportion of mesophase polycyclic aromatic compound (3) used is
The amount of the random copolymer (2) is preferably 5 to 900 parts per 100 parts, and if less than 5 parts, the amount of components having orientation in the produced polymer will be insufficient. However, highly elastic fibers and molded products cannot be obtained, and
When the amount is more than 900 parts, fibers having excellent wettability with respect to the matrix and a molded article having improved oxidation resistance cannot be obtained due to lack of silicon component.

When the melt-mixing temperature is lower than 200 ° C, an infusible portion is generated,
If the system becomes heterogeneous, and if the melt-mixing temperature is higher than 500 ° C, the condensation reaction will proceed violently, and the resulting polymer will have a high melting point and lose its fluidity.

(Effect) Since the silicon-containing polycyclic aromatic polymer according to the present invention contains an organosilicon copolymer and a mesophase polycyclic aromatic compound in the polymer, it is necessary to melt-spin, infusibilize, and calcine this polymer. Enables S on the graphite crystal of ultrafine particles.
It is possible to obtain a carbon-based inorganic fiber having a structure in which amorphous and / or β-SiC ultrafine particles composed of i, C, and O are dispersed, which has high strength and high elasticity and which is excellent in wettability with plastics. . As described above, there has been no fiber that can satisfy both mechanical properties and wettability with plastics at the same time, so that development of applications for FRP is particularly expected. Further, the fiber obtained from the polymer according to the present invention makes it possible to use the carbon-based fiber in a high temperature oxidizing atmosphere, and at the same time, the oxidation-resistant carbon-based material can be obtained by molding the polymer of the present invention. . Further, the present invention has a great advantage in terms of effective use of pitch.

(Examples) The present invention will be described below with reference to Examples.

Reference Example 1 (Production Method of Organosilicon Polymer) 2.5 l of anhydrous xylene and 40 parts of sodium were placed in a 5 l three-necked flask.
0 g was added, the mixture was heated to the boiling point of xylene under a nitrogen gas stream, and dimethyldichlorosilane 1 was added dropwise over 1 hour.
After completion of the dropping, the mixture was heated under reflux for 10 hours to form a precipitate. The precipitate was filtered, washed with methanol and then with water to obtain 420 g of white powdery polydimethylsilane.

This polydimethylsilane 400g, a gas introduction pipe, a stirrer,
Charge a 3 liter three-necked flask equipped with a condenser and a distillation tube,
Heat treatment was carried out at 420 ° C. under a nitrogen stream of 50 ml / min while stirring to obtain 350 g of a colorless transparent slightly viscous liquid in the distilling receiver.

The number average molecular weight of this liquid was 470 as measured by the vapor pressure osmosis method.

The infrared absorption spectrum of this substance was measured and found to be 65
Absorption of Si-CH ₃ in 0～900Cm ^-1 and 1250cm ^-1, Si-H to 2100 cm ^-1
Absorption of Si-CH ₂ at around 1020 cm ^-1 and at 1355 cm ^-1 , 2900
cm ^-1 and 2950 cm ^-1 absorption of CH is observed, also was measured far-infrared absorption spectrum of this material, 380 cm ^-1
Since the absorption of Si-Si is observed in, the obtained liquid substance is mainly composed of (Si-CH ₂ ) bond unit and (Si-Si) bond unit, and has a hydrogen atom and a methyl group in the side chain of silicon. It was found to be an organosilicon polymer having

From the measurement results of nuclear magnetic resonance analysis and infrared absorption analysis, this organosilicon polymer shows that the total number of (Si-CH ₂ ) bond units versus (Si-Si)
It was confirmed that the polymer had a ratio of the total number of bonding units of approximately 1: 3.

300 g of the above organosilicon polymer was treated with ethanol to remove low molecular weight substances, and 40 g of a polymer having a number average molecular weight of 1200 was obtained.

When the infrared absorption spectrum of this substance was measured, the same absorption peak as above was observed.
It was revealed that the organosilicon polymer is composed of a (Si—CH ₂ ) bond unit and a (Si—Si) bond unit and has a hydrogen atom and a methyl group in the side chain of silicon.

From the measurement results of nuclear magnetic resonance analysis and infrared absorption analysis, this organosilicon polymer shows that the total number of (Si-CH ₂ ) bond units versus (Si-Si)
It was confirmed that the polymer had a ratio of the total number of bonding units of approximately 7: 1.

Reference Example 2 (Production method of FCC slurry oil) Among petroleum fractions, high-boiling substances above light oil were subjected to fluid catalytic cracking at a temperature of 500 ° C in the presence of a silica-alumina cracking catalyst.
Fractionation was performed to obtain a residue from the bottom of the column. Below this residue
Called FCC slurry oil.

As a result of elemental analysis, the FCC slurry oil had an atomic ratio of carbon atoms to hydrogen atoms (C / H) of 0.75, and an aromatic carbon fraction by nuclear magnetic resonance analysis of 0.55.

Example 1 (First Step) 100 g of the FCC slurry oil obtained in Reference Example 2 was heated to 420 ° C. under a nitrogen gas stream, the distillate at the same temperature was distilled off, and the residue was hot filtered at 150 ° C. The infusible portion at the same temperature was removed to obtain a light content removal pitch of 98 g.

Xylene solubles are removed from this light content removal pitch,
60 g of xylene-insoluble component was obtained.

To 60 g of this xylene-insoluble component, 25 g of the organosilicon polymer obtained in Reference Example 1 and 20 ml of xylene were added, the temperature was raised with stirring, and xylene was distilled off and reacted at 400 ° C. for 4 hours to give 58 g of a random copolymer (2 ) Got.

As a result of infrared absorption spectrum measurement, this random copolymer (2) was found to have Si-H bonds (IR: 2) present in the organosilicon polymer.
100cm ^-1 ) decrease and new Si-C (carbon of benzene ring)
The formation of the bond (IR: 1135 cm ^-1 ) was confirmed, and it was found that a part of the silicon atoms of the organosilicon polymer has a part directly bonded to the polycyclic aromatic ring.

In addition, this copolymer did not contain a xylene-insoluble portion, had a weight average molecular weight of 1250 and a melting point of 248 ° C.

(Second step) 500 g of the FCC slurry oil obtained in Reference Example 2 was heated to 450 ° C under a nitrogen gas stream, the distillate at the same temperature was distilled off, and the residue was filtered while hot at 200 ° C. The infusible part at the temperature was removed to obtain 225 g of a light material removal pitch.

Xylene solubles are removed from this light content removal pitch,
180 g of xylene insoluble matter was obtained.

180 g of this xylene-insoluble matter was subjected to polycondensation at 400 ° C. for 6 hours under a nitrogen stream while removing the light components produced by the reaction to obtain 96 g of a heat-treated pitch. This heat-treated pitch had a melting point of 262 ° C., contained 7% of quinoline-insoluble matter, and had a mesophase pitch of 96% in terms of optical anisotropy observed by a polarizing microscope on the polished surface.

(Third step) 40 g of the random copolymer (2) obtained in the first step and the second step
Processed mesophase polycyclic aromatic polymer (3) 80
g was melt-mixed in a nitrogen atmosphere at 350 ° C. for 1 hour to obtain a silicon-containing polycyclic aromatic polymer in a uniform state.

This silicon-containing polycyclic aromatic polymer has a degree of optical anisotropy.
58%, xylene insoluble content 71%, melting point 241 ℃, hydrogenated under mild conditions, the weight average molecular weight (M _w ) was measured by gel permeation chromatography (GPC), M _w = 1025.

This silicon-containing polycyclic aromatic polymer is heated in air to 1000 ° C., the obtained ash is subjected to alkali melting and hydrochloric acid treatment,
After dissolving in water, the silicon concentration of the aqueous solution was measured using a high-frequency plasma emission spectrophotometer (ICP). The silicon content in the silicon-containing polycyclic aromatic polymer was
It was found to be 4.8%.

Example 2 (First Step) Benzene was used as the light content removal pitch cleaning solvent instead of xylene, and the ratio of the organosilicon polymer to the benzene insoluble content was 60.
Parts: Random copolymer (2) was obtained in the same manner as in Example 1 except that the content was changed to 40 parts and the copolymerization temperature was 420 ° C. for 2.5 hours. This copolymer had a melting point of 256 ° C. and a weight average molecular weight (M _w ) of 1480.

(Second Step) A mesophase-containing pitch was obtained in the same manner as in Example 1 except that toluene was used as the light content removal pitch cleaning solvent instead of xylene, and the heat treatment conditions were 380 ° C. and 12 hours. This pitch has a melting point of 248 ° C and contains 5% quinoline insoluble matter.
The mesophase pitch was 75% in terms of optical anisotropy observed by a polarizing microscope on the polished surface.

(Third Step) The charging ratio of the random copolymer (2) obtained in the first step and the mesophase polycyclic aromatic polymer (3) obtained in the second step
A silicon-containing polycyclic aromatic polymer was obtained in the same manner as in Example 1 except that the mixing ratio was 40 parts: 60 parts and the melt mixing temperature was 370 ° C. for 30 minutes.

This polymer has a melting point of 255 ° C and a quinoline insoluble content of 58%.
Included, the optical anisotropy is 45%, the weight average molecular weight (M _w ) is 12
At 10, the silicon content was 8.5%.

Comparative Example 1 (First Step) 200 g of the FCC slurry oil obtained in Reference Example 2 was heated to 420 ° C. under a nitrogen gas stream, and the light fraction at the same temperature was distilled off to obtain 114 g of a light fraction removal pitch. The obtained pitch is
After dissolving in 500 ml of xylene at 130 ° C. and removing 69 g of xylene-insoluble matter, 45 g of the xylene-soluble portion in the obtained pitch was added with 45 g of the organosilicon polymer obtained in Reference Example 1, and the mixture was mixed at 400 ° C. for 6 hours. Polymerization was carried out to obtain 32 g of a random copolymer.

(Second Step) 200 g of the xylene-soluble pitch component obtained in the first step was heat-treated at 400 ° C. for 6 hours in a nitrogen atmosphere to obtain a heat-treated pitch 41 g.

(Third Step) 30 g of the random copolymer obtained in the first step and 60 g of the heat-treated pitch obtained in the second step were heated and mixed at 300 ° C. for 2.5 hours.

The obtained product had a weight average molecular weight (M _w ) of 1750 and a silicon content of 10.5%, but had a low melting point of 198 ° C and an optical isotropy containing only 11% of xylene-insoluble matter. Was a polymer of.

Comparative Example 2 50 g of the organosilicon polymer obtained in Reference Example 1 was added to 100 g of the light component removal pitch obtained in Example 1 and reacted at 400 ° C. for 6 hours to obtain 79 g of a random copolymer.

The obtained copolymer has a melting point of 261 ° C and a silicon content of 15%.
And the average weight molecular weight (M _w ) was 1450.

Example 3 The silicon-containing polycyclic aromatic polymer obtained in Example 1 and Example 2 was used as a spinning dope, and melt-spun using a nozzle having a diameter of 0.3 mm. The obtained precursor yarn is 300 ° C under air circulation.
Was infusible and was fired at 1300 ° C. in an argon stream to obtain a carbonized inorganic fiber. The yarn diameter, tensile strength, and tensile elastic modulus of this fiber are 12 μm and 28 μm in the case of the dope of Example 1, respectively.
8 kg / mm ² , 26 t / mm ² , in the case of the dope of Example 2, 11 μ,
The values were 270 kg / mm ² and 24 t / mm ² .

Scanning electron microscope observation shows that both fibers have a cross-sectional structure similar to the radial structure used in pitch fibers, and the mesophase component in the dope was oriented along the fiber axis during spinning, infusibilization, and firing. Was showing that.

Comparative Example 3 The polymers obtained in Comparative Examples 1 and 2 were spun, infusibilized and fired under the same conditions as in Example 9 to obtain a fired yarn. The thread diameter, tensile strength, and tensile elastic modulus of each fiber are 17μ in the case of the dope of Comparative Example 1, 105 kg / mm ² , 7.1 t / mm ² , and 16μ in the case of the dope of Comparative Example 2, respectively. It was 80 kg / mm ² and 5.5 t / mm ² .

Further, the fiber cross section did not include a portion having an oriented structure.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaki Shibuya 5 1978, Kogushi, Ube-shi, Yamaguchi Prefecture 5 Ube Kosan Co., Ltd.

Claims (1)

[Claims] 1. A bond unit (Si—CH ₂ ) or a bond unit (S)
i-CH ₂ ) and a bonding unit (Si-Si), having a substituent selected from the group consisting of a hydrogen atom, a lower alkyl group, a phenyl group and a silyl group in the side chain of the silicon raw paper, and a bonding unit.
The ratio of the total number of (Si-CH ₂ ) to the total number of bonding units (Si-Si) is 1: 0 to 20.
At least a part of the silicon element of the organosilicon polymer in the range of is a petroleum-based or coal-based pitch or a heat-treated product thereof, and a polycyclic aromatic compound obtained from a pitch from which a soluble component in an organic solvent has been removed 100 parts by weight of a random copolymer bonded to the carbon of the aromatic ring of the compound, and ii) mesophase or mesophase obtained by further heat-treating an organic solvent-insoluble component in petroleum-based or coal-based pitch or a heat-treated product thereof and optical A silicon-containing polycyclic aromatic compound, characterized in that 5 to 900 parts by weight of a polycyclic aromatic compound composed of both a phase and an isotropic phase are heated and reacted and / or melted at a temperature in the range of 200 to 500 ° C. Method for producing polymer.