JP2005307403A - Polybenzobisoxazole fiber excellent in spinnability - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for obtaining polybenzobisoxasole (PBO) fiber having high physical properties by spinning dope having high degree of polymerization and excellent in spinnability. <P>SOLUTION: The PBO fiber having high physical properties is obtained by hydrolyzing and reducing 2-sulfonic acid-4,6-dinitroresorcinol and polymerizing the resultant high-purity 4,6-diaminoresorcinol to afford a high molecular weight PBO and spinning the PBO. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a spinning method of polybenzobisoxazole (hereinafter referred to as PBO) that can be formed into a high-strength and high-modulus fiber.

ここで式中のＡｒは芳香族基であり、Ｙはカルボキシル基、カルボン酸ハライド基、ハロアルキル基、ニトリル基などの電子不足炭素を有する官能基である。 PBO is a polymer represented by the following general formula structure (C), and can be obtained by a condensation reaction of the compounds (A) and (B) as shown in the following reaction formula.

Here, Ar in the formula is an aromatic group, and Y is a functional group having an electron-deficient carbon such as a carboxyl group, a carboxylic acid halide group, a haloalkyl group, or a nitrile group.

  The use of PBO thus obtained is for fibers and films, but its physical properties such as strength and elastic modulus, and spinnability are greatly affected by the degree of polymerization of the polymer. In general, in the polycondensation reaction, it is known that the polymer viscosity obtained becomes maximum when the monomer charge ratio is 1: 1 and rapidly decreases as the monomer charge ratio deviates from 1: 1. That is, in order to obtain satisfactory physical properties and spinnability, it is necessary to strictly control the monomer charge ratio and supply a polymer having a sufficient degree of polymerization.

  However, if the monomer contains a large amount of impurities, it is difficult to manage the monomer charge ratio. It becomes a factor causing a decrease in the degree of polymerization and spinnability. In order to obtain a polymer having a sufficient degree of polymerization and excellent spinnability, it is necessary to use high-purity monomers that do not contain impurities such as monoamines and triamines.

  4,6-Diaminoresorcin has been used as a monomer for PBO, and various synthetic methods have been reported. For example, a method in which resorcin is acetylated, nitrated, hydrolyzed and reduced (Ber. Dtch. Chem., 16, 552, 1883), 1,3-bis (alkyl carbonate) benzene is nitrated, hydrolyzed and reduced There is a method (Japanese Patent Laid-Open No. 2-136). However, in these methods, there is a problem that a trinitro body is formed in nitration and becomes a triamino body in the reduction step to cause three-dimensional crosslinking, resulting in a decrease in spinnability. As another method, Japanese Patent Application Laid-Open No. 7-242604 and Japanese Patent Application Laid-Open No. 9-124575 propose methods in which aniline is diazotized and diazo-coupled with resorcin and then hydrocracked. In the case of aniline, aniline generated by hydrogenolysis is mixed in the product, and there is a possibility that a sufficient degree of polymerization cannot be obtained and the spinnability is lowered. On the other hand, hydrolysis of 2-sulfonic acid-4,6-dinitroresorcin yields 4,6-dinitroresorcin, which does not contain isomers or trinitro, and is reduced to high purity 4,6. A method for obtaining diaminoresorcin has been proposed in JP 2000-319231 A. When polymerized using this high purity 4,6-diaminoresorcin, high molecular weight PBO is obtained without polymerization inhibition or three-dimensional crosslinking (Japanese Patent Laid-Open No. 2001-139985).

  An object of the present invention is to provide a method for obtaining PBO fibers having high physical properties excellent in spinnability by using a dope having a high polymerization degree obtained by polymerization using high-purity 4,6-diaminoresorcin.

  The present invention uses a high molecular weight PBO obtained by polymerizing with a high-purity 4,6-diaminoresorcin obtained by hydrolyzing 2-sulfonic acid-4,6-dinitroresorcin and reducing it. Thus, it is to obtain PBO fibers having high physical properties excellent in spinnability.

  The 4,6-diaminoresorcinol synthesized from 2-sulfone-4,6-dinitroresorcin in the present invention does not contain a monoamino or trinitro compound that can be a polymerization inhibitor, and is therefore a polybenzobispolymerized using the compound. Oxazole has a sufficient molecular weight, excellent spinnability, and exhibits excellent properties by spinning. That is, according to the present invention, polybenzobisoxazole fibers can be produced industrially advantageously.

  PBO used in the present invention is polymerized using high-purity 4,6-diaminoresorcin obtained by hydrolyzing 2-sulfonic acid-4,6-dinitroresorcin and reducing it. Since this monomer does not contain a mononitro compound or a trinitro compound in the production process, there is no possibility of producing a monoamino compound or a triamino compound that can be an inhibitor during polymerization.

The polymerization using this high purity 4,6-diaminoresorcin can be carried out by a known method. For example, phosphorus pentoxide is added to polyphosphoric acid under a nitrogen stream, and the 4,6-diaminoresorcin dihydrochloride, 4,6-diaminoresorcin and an approximately equimolar amount of aromatic dicarboxylic acid are added and heated and stirred. Is obtained. As the aromatic dicarboxylic acid, for example, terephthalic acid, isophthalic acid, 4,4′-bis (benzoic acid), 4,4′-oxybis (benzoic acid), 2,6-naphthalenedicarboxylic acid and the like can be used.
Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited by the following examples, and is appropriately modified within a range that can be adapted to the gist of the front and rear machines. Of course, it is also possible and they are all included in the technical scope of the present invention.

(Intrinsic viscosity)
The viscosity of a polymer solution prepared to a concentration of 0.5 g / l using methanesulfonic acid as a solvent was measured and calculated using a Ostwald viscometer in a thermostatic chamber at 25 ° C.
The polymerized PBO dope was spun under conditions such that the filament diameter was 11.5 μm and 1.5 denier. The filament was extruded from a nozzle having a spinning temperature of 175 ° C. with a pore diameter of 180 μm and a pore number of 166 into a multifilament by converging the filament at an appropriate position. A quench chamber was installed in the air gap between the spinning nozzle and the first cleaning bath so that the filaments were stretched at a more uniform temperature. The air gap length was 30 cm. Filaments were spun in air at 60 ° C. The take-up speed was 200 m / min, and the spinning draw ratio was 30. The PBO fiber was washed with water until the residual phosphorus concentration was 6000 ppm or less. Further, the mixture was neutralized with 1% NaOH aqueous solution for 10 seconds, washed with water for 30 seconds, dried at 200 ° C. for 3 minutes, and the yarn was wound around a yarn tube.
Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited by the following examples, and is appropriately modified within a range that can be adapted to the gist of the front and rear machines. Of course, it is also possible and they are all included in the technical scope of the present invention.

(Example 1)
After adding 5.33 kg of phosphorus pentoxide to 16.37 kg of 116% polyphosphoric acid under a nitrogen stream, 3.56 kg of 4,6-diaminoresorcin and 2.69 kg of terephthalic acid were added. Stir and mix for minutes. The temperature was further raised to 130 ° C., and the mixture was stirred and mixed for 2 hours to remove hydrochloric acid. Then, it superposed | polymerized using the biaxial extruder heated at 210 degreeC, and obtained PBO polymer dope. The color of the polymer dope was yellow and the intrinsic viscosity was 28.4 dl / g. The polymerized PBO dope was spun under conditions such that the filament diameter was 11.5 μm and 1.5 denier. The filament was extruded from a nozzle having a spinning temperature of 175 ° C. with a pore diameter of 180 μm and a pore number of 166 into a multifilament by converging the filament at an appropriate position. A quench chamber was installed in the air gap between the spinning nozzle and the first cleaning bath so that the filaments were stretched at a more uniform temperature. The air gap length was 30 cm. Filaments were spun in air at 60 ° C. The take-up speed was 200 m / min, and the spinning draw ratio was 30. The PBO fiber was washed with water until the residual phosphorus concentration was 6000 ppm or less. Further, the mixture was neutralized with 1% NaOH aqueous solution for 10 seconds, washed with water for 30 seconds, dried at 200 ° C. for 3 minutes, and the yarn was wound around a yarn tube. The obtained yarn had a strength of 39.2 cN / dTex and an elastic modulus of 1152 cN / dTex. During spinning, no single yarn breakage occurred in 120 minutes (24 km).

(Comparative Example 1)
After adding 5.27 kg of phosphorus pentoxide under nitrogen flow to 16.19 kg of 116% polyphosphoric acid, 3.52 kg of 4,6-diaminoresorcinol synthesized using 1,3-bis (alkyl carbonate) benzene as a starting material And 2.66 kg of terephthalic acid were added, and the mixture was stirred and mixed in the reactor at 60 ° C. for 10 minutes. The temperature was further raised to 130 ° C., and the mixture was stirred and mixed for 2 hours to remove hydrochloric acid. Then, it superposed | polymerized using the biaxial extruder heated at 210 degreeC, and obtained PBO polymer dope. The color of the polymer dope was yellow and the intrinsic viscosity was 29.3 dl / g. Spinning was carried out by the method described in Example 1. The strength of the obtained yarn was 37.4 cN / dTex, and the elastic modulus was 1143 cN / dTex. During spinning, the number of occurrences of single yarn breakage was 2 times within 120 minutes (24 km).

  According to the present invention, it is possible to provide a polybenzazole fiber that can sufficiently exhibit strength and elastic modulus due to good spinnability. Therefore, the effect of enhancing practicality as an industrial material and expanding the field of use is tremendous. is there. In other words, applications that are processed into woven fabrics, knitted fabrics, braids, ropes, cords, etc., that is, tension members such as cables, electric wires and optical fibers, tension materials such as ropes, impact-resistant members such as bullet-proof materials, and cut-off resistance such as gloves It can be used for a wide range of applications, such as rubber reinforcements such as creative members, belts, tires, shoe soles, ropes, hoses and the like.

Claims (1)

  It is characterized by using polybenzobisoxazole obtained by reacting 4,6-diaminoresorcinol obtained by hydrolysis of 2-sulfonic acid-4,6-dinitroresorcin and then reducing it, and aromatic dicarboxylic acid. Polybenzobisoxazole fiber with excellent spinnability.