JP2006219773A - Polybenzazole fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polybenzazole fiber having a remarkably improved compression strength in comparison with conventional polybenzazole fibers. <P>SOLUTION: This polybenzazole fiber is characterized by applying an intermolecular chain cross-linking treatment to a polybenzazole fiber comprising a polybenzazole polymer to whose each benzazole skeleton a side chain such as a 1 to 6C alkyl, for example, methyl or ethyl, or a halogen group is introduced, to give a compression strength of ≥0.5 GPa. A heating treatment in a 300 to 600°C inert gas or an active energy ray-irradiation treatment in an inert gas is adopted as the intermolecular chain cross-linking treatment. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polybenzazole fiber excellent in compressive strength.

A solution of rigid polymer, so-called liquid crystalline polymer, has the property that molecular chains tend to be oriented in the flow direction and it takes a long time for the molecular chains to change to a random orientation once oriented. -A high elastic modulus molded body can be manufactured. Furthermore, since a rigid polymer has a high glass transition temperature, a heat-resistant molded product can be obtained.
JP-A-6-341015

  Thus, the fiber manufactured from the polybenzazole polymer which is a rigid polymer shows the outstanding intensity | strength, elastic modulus, and heat resistance, and its application field is wide. However, the compressive strength is only 0.4 GPa at present, and it cannot be said that the compressive strength is sufficient for application to rubber reinforcing materials such as tire cords and belts, and composite materials used in aircraft. Further improvement is desired.

  The present invention has been made paying attention to the above circumstances, and an object thereof is to provide a polybenzazole fiber having a better compressive strength.

但し、ｎは０以上１未満の実数である。ＸはＳ、Ｏ原子またはＮＨ基を示す。アゾール環においてＮ原子とＸ原子／基はトランス位であってもシス位であっても良い。Ｙは

で表され、これらが単独、または１〜ｎの範囲内でこれら３つの繰り返し単位が任意の割合で共重合していてもよい。また、Ｒはハロゲン原子または炭素原子数１〜６のアルキル基を示す。
さらに、分子鎖間架橋処理は、３００〜６００℃の不活性ガス下の加熱処理や活性エネルギー線照射が好ましい態様である。 The present invention is characterized in that a polybenzazole fiber composed of polybenzazole having a side chain in the benzazole skeleton of polybenzazole is subjected to intermolecular cross-linking treatment, and the compressive strength is 0.5 GPa or more. Polybenzazole fiber.
Further, as a preferred embodiment, the polybenzazole fiber is a polybenzazole fiber having a molecular structure represented by the following general formula (1).

However, n is a real number of 0 or more and less than 1. X represents an S, O atom or NH group. In the azole ring, the N atom and the X atom / group may be trans or cis. Y is

These may be used alone or in the range of 1 to n, and these three repeating units may be copolymerized at an arbitrary ratio. R represents a halogen atom or an alkyl group having 1 to 6 carbon atoms.
Furthermore, the intermolecular chain crosslinking treatment is preferably a heat treatment under an inert gas at 300 to 600 ° C. or active energy ray irradiation.

  According to the present invention, cross-linking between polybenzazole molecular chains is easy by a simple treatment such as irradiation with heat or active energy rays, and by cross-linking after fiber formation, compared to conventional polybenzazole fibers, It has become possible to provide polybenzazole fibers having excellent compressive strength.

Hereinafter, the present invention will be described in detail.
The polybenzazole according to the present invention (hereinafter also referred to as PBZ) is from polybenzoxazole (hereinafter also referred to as PBO), polybenzothiazole (hereinafter also referred to as PBT), and polybenzimidazole (hereinafter also referred to as PBI). Say the polymer chosen.
The polybenzazole polymer that forms the polybenzazole fiber according to the present invention includes an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, and a tert-butyl group on a benzazole skeleton (azole ring), halogen This is a polybenzazole polymer having side chains such as groups, and after formation of fibers, when heat treatment or active energy ray treatment is applied, radicals are generated and the cross-chain cross-linking occurs due to the side chain action. Is formed.
Preferably, it is polybenzazole in which the repeating unit represented by the general formula (1) in the molecular chain is random or block copolymerized.
The following are mentioned as a preferable homopolymer and copolymer in this invention.

等が挙げられるが、もちろん本発明技術内容はこれらに限定されるものではない。

Of course, the technical contents of the present invention are not limited to these.

  Since the degree of polymerization tends to increase and high physical properties can be obtained, the polymer copolymerization ratio is preferably 20 to 70%, more preferably 30 to 50%. Outside this range, the degree of polymerization increases but the desired physical properties cannot be obtained, and high physical properties can be expected, but the degree of polymerization is difficult to increase.

  Polybenzazole fibers are manufactured from a dope containing a polybenzazole polymer, and suitable solvents for preparing the dope include cresol and a non-oxidizing acid capable of dissolving the polymer. Examples of suitable non-oxidizing acids include polyphosphoric acid, methanesulfonic acid and high concentrations of sulfuric acid or mixtures thereof. Of these, polyphosphoric acid and methanesulfonic acid, particularly polyphosphoric acid are preferred.

  The polymer concentration in the dope is preferably at least about 7% by weight, more preferably at least 10% by weight. The maximum concentration is limited by practical handling properties such as polymer solubility and dope viscosity. Due to their limiting factors, the polymer concentration usually does not exceed 20% by weight.

  In the present invention, suitable polymers or copolymers and dopes are synthesized by known methods. For example, Wolfe et al., US Pat. No. 4,533,693, Sybert et al., US Pat. No. 4,772,678, Harris, US Pat. No. 4,847,350, or Gregory et al., US Pat. No. 5,089,591. In summary, suitable monomers are heated in a non-oxidizing, dehydrating acid solution at a stepwise or constant rate of heating from about 60 ° C. to 230 ° C. under high-speed stirring and high shear conditions in a non-oxidizing atmosphere. It is made to react by raising.

  The dope thus obtained is extruded from the spinneret and stretched in space to form a filament. A suitable manufacturing method is described in US Pat. No. 5,034,250. The dope exiting the spinneret enters the space between the spinneret and the washing bath. This space is commonly referred to as an air gap, but need not be air. This space needs to be filled with a solvent that does not react with the dope without removing the solvent, and examples thereof include air, nitrogen, argon, helium, and carbon dioxide.

  The filament after spinning is washed to avoid excessive stretching and a part of the solvent is removed. Then, it is further washed and appropriately neutralized with an inorganic base such as sodium hydroxide, calcium hydroxide or potassium hydroxide, and most of the solvent is removed. Washing here is compatible with the mineral acid dissolving the polybenzazole polymer, and the fiber or filament is brought into contact with a liquid that does not serve as a solvent for the polybenzazole polymer to remove the acid solvent from the dope. It is to be. Suitable cleaning liquids include water and mixtures of water and acid solvents. The filament is preferably washed to a residual mineral acid metal atom concentration of 8000 ppm or less by weight, more preferably 5000 ppm or less. Thereafter, the filament is subjected to drying, heat treatment, winding and the like as necessary.

  The filaments thus obtained are cross-linked by treating them under an inert gas. The treatment here is heating at 300 to 600 ° C. or irradiation with active energy. The active energy rays are ultraviolet rays having a wavelength of 210 to 330 nm, light irradiation by a deuterium lamp, a mercury lamp, and a xenon lamp, radiation, an electron beam, and the like. Nitrogen, argon, etc. are generally used as the inert gas.

The intermolecular crosslinking in the present invention involves R in the general formula (1), that is, an alkyl group such as a methyl group or an ethyl group in the benzazole skeleton, or a side chain such as a halogen group. Radiation is generated by the irradiation of rays and crosslinks between molecular chains.
For example, when R is a methyl group, the following crosslinked structure is obtained.

Such crosslinking can be confirmed by measuring ¹³ C solid state NMR of the untreated filament and the treated filament. In the case of having a methyl group, the signal based on the methyl group decreases, and a new signal based on the methylene group can be observed. Moreover, when it has an ethyl group, the signal based on an ethyl group reduces and the signal of the methylene group different from the methylene group of an ethyl group can be observed. Further, in the case of having a halogen group, a high magnetic field shift of the carbon signal to which the halogen group is bonded is observed.

Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited by the following examples, but may be implemented with appropriate modifications within a range that can meet the gist of the preceding and following descriptions. Of course, it is also possible and they are all included in the technical scope of the present invention.
(Intrinsic viscosity)
The viscosity of the polymer solution prepared to a concentration of 0.5 g / l using methanesulfonic acid as a solvent was measured and calculated in an oven at 25 ° C. using an Ostwald viscometer.

(Confirmation method of crosslinking)
About the filament before a process and the filament after a process, about 300 mg of samples were put into 7 mm (phi) CP / MAS probe, and ¹³ C solid state NMR was measured on the conditions of room temperature, the integration frequency of 1024 times, and the pulse interval time of 20 seconds.

(Compressive strength measurement)
Measurement was performed using Raman scattering. The Raman measurement apparatus (spectrometer) was measured using a Renishaw system 1000, and the light source was measured using a helium-neon laser (wavelength 633 nm). Details of the measurement were performed according to the method of Young et al., For example, Polymer 40, 3421 (1999). The compression strength was determined by monitoring the change of the 1619 cm ^-1 band caused by the expansion and contraction of the benzene ring of PBO.

Example 1
Under a nitrogen stream, 5.1 g of 4,6-diaminoresorcin dihydrochloride, 0.6 g of 2-methyl-4,6-diaminoresorcin dihydrochloride, 4.5 g of terephthalic acid, and five The phosphorus oxide 8.2g was added, and it stirred and mixed in the reactor at 70 degreeC for 15 minutes. Further, the temperature was raised to 120 ° C., mixed with stirring for 3.5 hours to remove hydrochloric acid, heated to 135 ° C. and stirred for 19 hours to oligomerize. Then, it heated up at 200 degreeC and superposed | polymerized and obtained the PBO polymer dope. The color of the polymer dope was yellow and the intrinsic viscosity was 25 dl / g.
The polymerized dope was extruded from a single-hole nozzle having a pore diameter of 200 μm at a spinning temperature of 175 ° C., and the filament was solidified in a water bath and wound around a yarn tube. The winding speed was 100 m / min. The wound yarn was washed with water for 18 hours, neutralized with 1% NaOH aqueous solution for 30 minutes, and further washed with water for 1 to 24 hours. Drying was performed at 80 ° C. for 4 hours.
The obtained filament was heat-treated at 500 ° C. for 1 hour under a nitrogen stream. Table 1 shows the evaluation results of the compressive strength.

(Example 2)
116% polyphosphoric acid 28.1 g under nitrogen stream, 4,6-diaminoresorcinol dihydrochloride 3.9 g, 2-methyl-4,6-diaminoresorcinol dihydrochloride 1.8 g, terephthalic acid 4.3 g and five 8.3 g of phosphorus oxide was added, and the mixture was stirred and mixed at 70 ° C. for 15 minutes in the reactor. Further, the temperature was raised to 120 ° C., mixed with stirring for 3.5 hours to remove hydrochloric acid, heated to 135 ° C. and stirred for 19 hours to oligomerize. Then, it heated up at 200 degreeC and superposed | polymerized and obtained the PBO polymer dope. The color of the polymer dope was yellow and the intrinsic viscosity was 26 dl / g.
The polymerized dope was extruded from a single-hole nozzle having a pore diameter of 200 μm at a spinning temperature of 175 ° C., and the filament was solidified in a water bath and wound around a yarn tube. The winding speed was 100 m / min. The wound yarn was washed with water for 18 hours, neutralized with 1% NaOH aqueous solution for 30 minutes, and further washed with water for 1 to 24 hours. Drying was performed at 80 ° C. for 4 hours.
The obtained filament was heat-treated at 500 ° C. for 1 hour under a nitrogen stream. Table 1 shows the evaluation results of the compressive strength.

(Example 3)
116% polyphosphoric acid 27.9 g under nitrogen flow, 4,6-diaminoresorcin dihydrochloride 2.8 g, 2-methyl-4,6-diaminoresorcin dihydrochloride 2.9 g, terephthalic acid 4.2 g and five The phosphorus oxide 8.2g was added, and it stirred and mixed in the reactor at 70 degreeC for 15 minutes. Further, the temperature was raised to 120 ° C., mixed with stirring for 3.5 hours to remove hydrochloric acid, heated to 135 ° C. and stirred for 19 hours to oligomerize. Then, it heated up at 200 degreeC and superposed | polymerized and obtained the PBO polymer dope. The color of the polymer dope was yellow and the intrinsic viscosity was 25 dl / g.
The polymerized dope was extruded from a single-hole nozzle having a pore diameter of 200 μm at a spinning temperature of 175 ° C., and the filament was solidified in a water bath and wound around a yarn tube. The winding speed was 100 m / min. The wound yarn was washed with water for 18 hours, neutralized with 1% NaOH aqueous solution for 30 minutes, and further washed with water for 1 to 24 hours. Drying was performed at 80 ° C. for 4 hours.
The obtained filament was heat-treated at 500 ° C. for 1 hour under a nitrogen stream. Table 1 shows the evaluation results of the compressive strength.

Example 4
116% polyphosphoric acid 28.2 g under nitrogen flow, 4,6-diaminoresorcinol dihydrochloride 1.7 g, 2-methyl-4,6-diaminoresorcinol dihydrochloride 4.0 g, terephthalic acid 4.3 g and five 8.1 g of phosphorus oxide was added, and the mixture was stirred and mixed at 70 ° C. for 15 minutes in the reactor. Further, the temperature was raised to 120 ° C., mixed with stirring for 3.5 hours to remove hydrochloric acid, heated to 135 ° C. and stirred for 19 hours to oligomerize. Then, it heated up at 200 degreeC and superposed | polymerized and obtained the PBO polymer dope. The color of the polymer dope was yellow and the intrinsic viscosity was 24 dl / g.
The polymerized dope was extruded from a single-hole nozzle having a pore diameter of 200 μm at a spinning temperature of 175 ° C., and the filament was solidified in a water bath and wound around a yarn tube. The winding speed was 100 m / min. The wound yarn was washed with water for 18 hours, neutralized with 1% NaOH aqueous solution for 30 minutes, and further washed with water for 1 to 24 hours. Drying was performed at 80 ° C. for 4 hours.
The obtained filament was heat-treated at 500 ° C. for 1 hour under a nitrogen stream. Table 1 shows the evaluation results of the compressive strength.

(Example 5)
Under a nitrogen stream, 5.8 g of 2-methyl-4,6-diaminoresorcin dihydrochloride, 4.2 g of terephthalic acid and 8.0 g of phosphorus pentoxide were added to 29.0 g of 116% polyphosphoric acid. Stir and mix at 15 ° C. for 15 minutes. Further, the temperature was raised to 120 ° C., mixed with stirring for 3.5 hours to remove hydrochloric acid, heated to 135 ° C. and stirred for 19 hours to oligomerize. Then, it heated up at 200 degreeC and superposed | polymerized and obtained the PBO polymer dope. The color of the polymer dope was yellow and the intrinsic viscosity was 26 dl / g.
The polymerized dope was extruded from a single-hole nozzle having a pore diameter of 200 μm at a spinning temperature of 175 ° C., and the filament was solidified in a water bath and wound around a yarn tube. The winding speed was 100 m / min. The wound yarn was washed with water for 18 hours, neutralized with 1% NaOH aqueous solution for 30 minutes, and further washed with water for 1 to 24 hours. Drying was performed at 80 ° C. for 4 hours.
The obtained filament was heat-treated at 500 ° C. for 1 hour under a nitrogen stream. Table 1 shows the evaluation results of the compressive strength.

(Example 6)
116% polyphosphoric acid 28.4 g under nitrogen stream, 4,6-diaminoresorcin dihydrochloride 3.8 g, 2-chloro-4,6-diaminoresorcin dihydrochloride 1.9 g, terephthalic acid 4.2 g and five 8.0 g of phosphorus oxide was added, and the mixture was stirred and mixed at 70 ° C. for 15 minutes in the reactor. Further, the temperature was raised to 120 ° C., mixed with stirring for 3.5 hours to remove hydrochloric acid, heated to 135 ° C. and stirred for 19 hours to oligomerize. Then, it heated up at 200 degreeC and superposed | polymerized and obtained the PBO polymer dope. The color of the polymer dope was yellow and the intrinsic viscosity was 26 dl / g.
The polymerized dope was extruded from a single-hole nozzle having a pore diameter of 200 μm at a spinning temperature of 175 ° C., and the filament was solidified in a water bath and wound around a yarn tube. The winding speed was 100 m / min. The wound yarn was washed with water for 18 hours, neutralized with 1% NaOH aqueous solution for 30 minutes, and further washed with water for 1 to 24 hours. Drying was performed at 80 ° C. for 4 hours.
The obtained filament was heat-treated at 500 ° C. for 1 hour under a nitrogen stream. Table 1 shows the evaluation results of the compressive strength.

(Example 7)
Under a nitrogen stream, 4.0 g of 4,6-diaminoresorcin dihydrochloride, 1.9 g of 2-ethyl-4,6-diaminoresorcin dihydrochloride, 4.4 g of terephthalic acid, and five compounds were added to 29.1 g of 116% polyphosphoric acid. 8.3 g of phosphorus oxide was added, and the mixture was stirred and mixed at 70 ° C. for 15 minutes in the reactor. Further, the temperature was raised to 120 ° C., mixed with stirring for 3.5 hours to remove hydrochloric acid, heated to 135 ° C. and stirred for 19 hours to oligomerize. Then, it heated up at 200 degreeC and superposed | polymerized and obtained the PBO polymer dope. The color of the polymer dope was yellow and the intrinsic viscosity was 25 dl / g.
The polymerized dope was extruded from a single-hole nozzle having a pore diameter of 200 μm at a spinning temperature of 175 ° C., and the filament was solidified in a water bath and wound around a yarn tube. The winding speed was 100 m / min. The wound yarn was washed with water for 18 hours, neutralized with 1% NaOH aqueous solution for 30 minutes, and further washed with water for 1 to 24 hours. Drying was performed at 80 ° C. for 4 hours.
The obtained filament was heat-treated at 500 ° C. for 1 hour under a nitrogen stream. Table 1 shows the evaluation results of the compressive strength.

(Example 8)
28.5 g of 116% polyphosphoric acid under a nitrogen stream, 2.7 g of 4,6-diaminoresorcin dihydrochloride, 1.3 g of 2-methyl-4,6-diaminoresorcin dihydrochloride, 4,4′-biphenyldicarboxylic acid The acid 4.4g and phosphorus pentoxide 5.4g were added, and it stirred and mixed in the reactor at 70 degreeC for 15 minutes. Further, the temperature was raised to 120 ° C., mixed with stirring for 3.5 hours to remove hydrochloric acid, heated to 135 ° C. and stirred for 19 hours to oligomerize. Then, it heated up at 200 degreeC and superposed | polymerized and obtained the PBO polymer dope. The color of the polymer dope was yellow and the intrinsic viscosity was 25 dl / g.
The polymerized dope was extruded from a single-hole nozzle having a pore diameter of 200 μm at a spinning temperature of 175 ° C., and the filament was solidified in a water bath and wound around a yarn tube. The winding speed was 100 m / min. The wound yarn was washed with water for 18 hours, neutralized with 1% NaOH aqueous solution for 30 minutes, and further washed with water for 1 to 24 hours. Drying was performed at 80 ° C. for 4 hours.
The obtained filament was heat-treated at 500 ° C. for 1 hour under a nitrogen stream. Table 1 shows the evaluation results of the compressive strength.

Example 9
1,3-dimercapto-4,6-diaminobenzene dihydrochloride 3.7 g, 1,3-dimercapto-2-methyl-4,6-diaminobenzene dihydrochloride in 27.8 g of 116% polyphosphoric acid under a nitrogen stream 1.7 g of salt, 3.7 g of terephthalic acid and 6.5 g of phosphorus pentoxide were added, and the mixture was stirred and mixed at 70 ° C. for 15 minutes in the reactor. Further, the temperature was raised to 120 ° C., mixed with stirring for 3.5 hours to remove hydrochloric acid, heated to 135 ° C. and stirred for 19 hours to oligomerize. Then, it heated up at 200 degreeC and superposed | polymerized and obtained the PBO polymer dope. The color of the polymer dope was yellow and the intrinsic viscosity was 25 dl / g.
The polymerized dope was extruded from a single-hole nozzle having a pore diameter of 200 μm at a spinning temperature of 175 ° C., and the filament was solidified in a water bath and wound around a yarn tube. The winding speed was 100 m / min. The wound yarn was washed with water for 18 hours, neutralized with 1% NaOH aqueous solution for 30 minutes, and further washed with water for 1 to 24 hours. Drying was performed at 80 ° C. for 4 hours.
The obtained filament was heat-treated at 500 ° C. for 1 hour under a nitrogen stream. Table 1 shows the evaluation results of the compressive strength.

(Comparative Example 1)
Under a nitrogen stream, 5.8 g of 4,6-diaminoresorcin, 4.4 g of terephthalic acid and 8.7 g of phosphorus pentoxide were added to 28.4 g of 116% polyphosphoric acid, and the mixture was stirred and mixed at 70 ° C. for 15 minutes. . Further, the temperature was raised to 120 ° C., mixed with stirring for 3.5 hours to remove hydrochloric acid, heated to 135 ° C. and stirred for 19 hours to oligomerize. Then, it heated up at 200 degreeC and superposed | polymerized and obtained the PBO polymer dope. The color of the polymer dope was yellow and the intrinsic viscosity was 28 dl / g.
The polymerized dope was extruded from a single-hole nozzle having a pore diameter of 200 μm at a spinning temperature of 175 ° C., and the filament was solidified in a water bath and wound around a yarn tube. The winding speed was 100 m / min. The wound yarn was washed with water for 18 hours, neutralized with 1% NaOH aqueous solution for 30 minutes, and further washed with water for 1 to 24 hours. Drying was performed at 80 ° C. for 4 hours.
The obtained filament was heat-treated at 500 ° C. for 1 hour under a nitrogen stream. Table 1 shows the evaluation results of the compressive strength.

(Comparative Example 2)
Under a nitrogen stream, 5.6 g of 4,6-diaminoresorcin, 4.3 g of terephthalic acid and 8.5 g of phosphorus pentoxide were added to 27.8 g of 116% polyphosphoric acid, and the mixture was stirred and mixed at 70 ° C. for 15 minutes. . Further, the temperature was raised to 120 ° C., mixed with stirring for 3.5 hours to remove hydrochloric acid, heated to 135 ° C. and stirred for 19 hours to oligomerize. Then, it heated up at 200 degreeC and superposed | polymerized and obtained the PBO polymer dope. The color of the polymer dope was yellow and the intrinsic viscosity was 27 dl / g.
The polymerized dope was extruded from a single-hole nozzle having a pore diameter of 200 μm at a spinning temperature of 175 ° C., and the filament was solidified in a water bath and wound around a yarn tube. The winding speed was 100 m / min. The wound yarn was washed with water for 18 hours, neutralized with 1% NaOH aqueous solution for 30 minutes, and further washed with water for 1 to 24 hours. Drying was performed at 80 ° C. for 4 hours.
The obtained filament was heat-treated at 500 ° C. for 1 hour under a nitrogen stream. Table 1 shows the evaluation results of the compressive strength.

  From the above, it is superior to the conventional one by crosslinking polybenzazole fiber having a structural unit in which an alkyl group such as a methyl group or an ethyl group or a halogen group is introduced on the benzazole skeleton (the benzene ring constituting the heterocycle). It can be seen that fibers having high compressive strength can be obtained.

According to the present invention, it is possible to provide a polybenzazole fiber having not only high strength, high elastic modulus, and high heat resistance, but also excellent compressive strength. Therefore, it has the effect of enhancing practicality as an industrial material and expanding the application field. It is huge. Paying particular attention to its high compression properties, it can be expected to be used as a rubber reinforcement for tire cords, belts, shoe soles, ropes, hoses, etc., as a composite material for aircraft materials and space development.
In addition to tension members such as cables, electric wires and optical fibers, ropes and other tension materials, rocket insulation, rocket casing, pressure vessels, space suit strings, planetary exploration balloons, etc., aviation, space materials, bulletproof materials, etc. High-density and high-density components for mounting silicon chips, impact-resistant materials, cut-resistant materials such as gloves, fire-resistant clothing, heat-resistant felt, plant gaskets, heat-resistant fabrics, various seals, heat-resistant cushions, and filters Components for electronic materials such as circuit boards, fishing lines, fishing rods, tennis rackets, table tennis rackets, badminton rackets, golf shafts, club heads, guts, strings, sail crosses, running shoes, marathon shoes, spike shoes, skate shoes, basketball shoes , Volleyball shoes, etc. Sports shoes, competition (running) bicycles and wheels, road racers, piste racers, mountain bikes, composite wheels, disc wheels, tension disks, spokes, brake wires, transmission wires, competition (running) wheelchairs and wheels, protectors , Racing suits, skis, stocks, helmets, parachutes and other sports-related materials, avance belts, friction materials such as clutch facings, various building material reinforcements and other rider suits, speaker cones, lightweight baby carriages, lightweight wheelchairs, lightweight It can be used for a wide range of applications such as nursing beds, lifeboats, and life jackets.

Claims (4)

A polybenzazole fiber comprising a polybenzazole fiber comprising polybenzazole having a side chain in the benzazole skeleton of polybenzazole, subjected to intermolecular cross-linking treatment, and having a compressive strength of 0.5 GPa or more. . A polybenzazole fiber, wherein the polybenzazole fiber has a molecular structure represented by the following general formula (1).

However, n is a real number of 0 or more and less than 1. X represents an S, O atom or NH group. In the azole ring, the N atom and the X atom / group may be trans or cis. Y is

These may be used alone or in the range of 1 to n, and these three repeating units may be copolymerized at an arbitrary ratio. R represents a halogen atom or an alkyl group having 1 to 6 carbon atoms. The polybenzazole fiber according to claim 1, wherein the intermolecular chain crosslinking treatment is a heat treatment under an inert gas at 300 to 600 ° C. The polybenzazole fiber according to claim 1, wherein the intermolecular chain crosslinking treatment is irradiation with active energy rays under an inert gas.