JP2006348441A - Polybenzazole fiber and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polybenzazole fiber prepared by imparting high conductivity to a polybenzazole of insulating material without deteriorating the original high strength, high heat resistance, flexural resistance and the like of the polybenzazole fiber. <P>SOLUTION: This polybenzazole fiber is characterized by containing a phthalocyanine compound and having conductivity of ≥1 (Ω cm)<SP>-1</SP>and a tensile strength of ≥4 GPa. The content of the phthalocyanine compound is preferably 5 to 50 mass%. The method for producing the polybenzazole fiber is characterized by extruding a polymer dope comprising the polybenzazole, a solvent for the polybenzazole, and a phthalocyanine compound from a spinneret, drawing the spun fiber, applying a treatment for extracting the solvent to the obtained fiber, dipping the fiber in an iodine-containing solution, washing the fiber water, and then drying the washed fiber. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polybenzazole fiber having electrical conductivity suitable as an industrial material and a method for producing the same.

As a fiber having high strength and high heat resistance, polybenzazole fiber composed of polybenzoxazole, polybenzothiazole, or a copolymer thereof is known (for example, Patent Document 1, Patent Document 2, Patent Document 3). .
However, polybenzazole fiber is an insulator and is excellent in electrical conductivity, that is, conductive polybenzazole fiber is not known.

US Pat. No. 5,385,702 W094 / 04726 specification US Pat. No. 5,296,185

  An object of the present invention is to provide a polybenzazole fiber that imparts high electrical conductivity to polybenzazole, which is an insulator, without impairing the inherent high strength, high heat resistance, and bending resistance of the polybenzazole fiber. That is.

The present invention is a polybenzazole fiber containing a phthalocyanine compound, having an electric conductivity of 1 (Ω · cm) ⁻¹ or more and a tensile strength of 4 GPa or more, and containing the phthalocyanine compound The polybenzazole fiber is characterized in that the ratio is 5% by mass or more and less than 50% by mass. Furthermore, the polymer dope containing polybenzazole, a solvent of the polybenzazole and a phthalocyanine compound is discharged from a spinneret, and after drawing into a yarn, the obtained yarn is subjected to an extraction treatment of the solvent, and Then, after immersing in an iodine-containing solution, it is washed with water and dried.

  According to the present invention, high electrical conductivity can be imparted to polybenzazole, which is an insulator, without compromising the inherent high strength, high heat resistance, flex resistance, etc. of polybenzazole fiber, and both high strength and conductivity are achieved. Provided fibers can be provided.

Hereinafter, the present invention will be described in detail.
The polybenzazole fiber according to the present invention refers to a fiber made of a polybenzazole polymer, and the polybenzazole (hereinafter also referred to as PBZ) refers to polybenzoxazole (hereinafter also referred to as PBO) or polybenzothiazole (hereinafter referred to as PBOZ). , PBT), or polybenzimidazole (hereinafter also referred to as PBI). In the present invention, PBO refers to a polymer containing an oxazole ring bonded to an aromatic group, and the aromatic group is not necessarily a benzene ring, and may be a biphenylene group, a naphthylene group, or the like. PBO refers to a polymer containing an oxazole ring bonded to an aromatic group, but the aromatic group need not necessarily be a benzene ring. Furthermore, PBO is not only a homopolymer of poly (p-phenylenebenzobisoxazole) but also a copolymer or aromatic in which a part of the phenylene group of poly (p-phenylenebenzobisoxazole) is substituted with a heterocyclic ring such as a pyridine ring. Polymers consisting of a plurality of oxazole ring units bonded to a group are widely included. The same applies to PBT and PBI. Also included are two or more mixtures of PBO, PBT and PBI, two or more block or random copolymers of PBO, PBT and PBI and mixtures of these polybenzazole polymers, copolymers, block polymers, etc. .

  The structural unit contained in the PBZ polymer is preferably selected from lyotropic liquid crystal polymers that form liquid crystals at a specific concentration. The polymer consists of monomer units described in structural formulas (a) to (h), and preferably consists essentially of monomer units selected from structural formulas (a) to (d). In addition, these monomer units may partially include monomer units having a substituent such as an alkyl group or a halogen group.

  Suitable solvents for forming the polymer dope include cresol and non-oxidizing acids that can dissolve the polymer. Examples of suitable acid solvents include polyphosphoric acid, methanesulfonic acid and high concentrations of sulfuric acid or mixtures thereof. Further suitable solvents are polyphosphoric acid and methanesulfonic acid. The most suitable solvent is polyphosphoric acid.

  The polymer concentration in the dope is preferably at least about 7% by weight, more preferably at least 10% by weight, particularly preferably at least 14% 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 (1985.8.6), Sybert et al US Pat. No. 4,772,678 (1988.9.22), Harris US Pat. No. 4,847,350 (1989.7.11) or Gregory et al. U.S. Pat. No. 5,089,591 (1992.2.18). 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.

In the polymerization dope, a phthalocyanine compound is uniformly dispersed and dissolved as a conductivity imparting substance.
The method for mixing the phthalocyanine compound in the spinning dope is not particularly limited, and the phthalocyanine compound can be mixed at any stage of polymerization of polybenzazole or at the stage of polymer dope at the end of polymerization. For example, a method of adding polybenzazole raw materials at the same time, a method of adding at a stage where the reaction is carried out by raising the temperature stepwise or at an arbitrary rate of temperature increase, and a method of adding into the reaction system at the end of the polymerization reaction The method of adding and stirring and mixing is preferable.

  As long as it has a phthalocyanine skeleton as a phthalocyanine compound, the presence or absence of a metal coordinated at the center and the atomic species are not limited. Specific examples of these compounds include 29H, 31H-phthalocyaninate (2-)-N29, N30, N31, N32 copper, 29H, 31H-phthalocyaninate (2-)-N29, N30, N31, N32 iron, 29H, 31H-phthalocyaninate-N29, N30, N31, N32 cobalt, 29H, 31H-phthalocyaninate (2-)-N29, N30, N31, N32 copper, oxo (29H, 31H-phthalate Russian titanate (2-)-N29, N30, N31, N32), (SP-5-12) titanium and the like. Further, these phthalocyanine skeletons may have one or more substituents such as a halogen atom, a methyl group, and a methoxy group. These phthalocyanine compounds may be used alone or in combination of two or more.

  The concentration of the phthalocyanine compound added to the polymer is preferably 5% by mass or more and less than 50% by mass, more preferably 10% by mass or more and less than 40% by mass, and most preferably 20% by mass or more and 30% by mass. Is less than. If the added amount is too small, the desired conductivity cannot be imparted, and if the added amount is too large, there may be a problem that the mechanical properties of the fiber are lowered.

  In this way, the polymer dope containing the phthalocyanine compound is supplied to the spinning section and is discharged from the spinneret into a non-solidifying gas such as nitrogen or air at a temperature of usually 100 ° C. or higher. A plurality of base pores are usually arranged in a circumferential shape or a lattice shape, but other arrangements may be used. The number of nozzle holes is not particularly limited, but the arrangement of the spinning holes on the spinneret surface needs to maintain a hole density that does not cause fusion between discharged yarns.

  The spun yarn needs a sufficiently long draw zone length in order to obtain a sufficient draw ratio (SDR), and is rectified at a relatively high temperature (above the dope solidification temperature and below the spinning temperature). It is desirable to cool uniformly with cooling air. The length (L) of the draw zone requires a length that completes solidification in a non-solidifying gas, and is determined by the single-hole discharge amount (Q). In order to obtain good fiber physical properties, the draw zone take-out stress needs to be 1.8 g / dtex or more in terms of polymer (assuming that only the polymer is stressed).

  The yarn drawn in the draw zone is then led to a medium bath for solvent extraction and yarn solidification. The extraction (coagulation) medium used in the extraction (coagulation) bath is preferably a liquid having a hydroxyl group in the molecule, that is, a solution prepared by mixing water, methanol, ethanol, ethylene glycol and phosphoric acid with these. Is water or a phosphoric acid aqueous solution.

The phosphoric acid concentration in the case of the phosphoric acid aqueous solution is 5% by mass or more and 60% by mass or less, more preferably 10% by mass or more and 50% by mass or less, and most preferably 20% by mass or more and 40% by mass or less. Furthermore, a preferable region for the solidification temperature is 5 ° C. or more and 60 ° C. or less, more preferably 10 ° C. or more and 50 ° C. or less, and most preferably 15 ° C. or more and 40 ° C. or less.

  After passing through the first extraction (coagulation) bath, the solution is further neutralized with an aqueous sodium hydroxide solution and the like, and phosphoric acid contained in the fibers (yarns) is extracted through a washing step such as a second extraction bath. Finally, extraction is performed so that the phosphoric acid contained in the yarn in the extraction bath is 1.0% by mass or less, preferably 0.5% by mass or less. The liquid used as the extraction medium in the present invention is not particularly limited, but water, methanol, ethanol, acetone, ethylene glycol and the like that are substantially incompatible with polybenzazole are preferable, and an aqueous phosphoric acid solution and water are more preferable. preferable. Alternatively, the extraction (coagulation) bath may be separated into multiple stages, the concentration of the phosphoric acid aqueous solution is successively reduced, and finally washed with water.

After the neutralization / extraction step, the fiber (yarn) is immersed in an iodine-containing liquid such as an aqueous potassium iodide solution, and then further washed with water and dried. If necessary, heat treatment may be performed after the neutralization / extraction step or after the iodine treatment.
When the phthalocyanine compound and iodine are present in the fiber, the detailed mechanism is not clear, but it is considered to be due to a doping effect that partially oxidizes the phthalocyanine compound contained therein, and the electrical conductivity is improved. The iodine content in the fiber is preferably 0.5% by mass or more and 10% by mass or less. If the iodine content is less than 0.5% by mass, the electrical conductivity is insufficiently developed, and if it exceeds 10% by mass, the fiber strength tends to be impaired.

  Since the extraction bath has a high spinning tension, it is not particularly necessary to consider the disturbance of the extraction bath, and any type of extraction bath may be used. For example, a funnel type, a water tank type, an aspirator type or a waterfall type can be used.

Hereinafter, the present invention will be described in detail by way of examples. In addition, the characteristic of the fiber of this invention was measured with the following method.
(Intrinsic viscosity)
Using methanesulfonic acid as a solvent, the viscosity of the polymer solution prepared at a concentration of 0.5 g / l was measured in an oven at 25 ° C. using an Ostwald viscometer.
(Moisture percentage)
The mass was calculated according to the following formula from the mass before drying: W0 (g) and the mass after drying: W1 (g). The drying was performed at 200 ° C. for 1 hour.
Moisture content (%) = (W0−W1) / W1 × 100
(Tensile strength, tensile modulus)
After being left in a test room in a standard state (temperature: 20 ± 2 ° C., relative humidity (RH) 65 ± 2%) for 24 hours or more, it was measured with a tensile tester according to JIS-L1015.

(Iodine content)
The fiber sample was combusted and decomposed by an oxygen flask method, and iodine ions in the absorbing solution were quantified using ion chromatography. The content was expressed as mass% based on the fiber sample.

(Measurement method of electrical conductivity)
The electric conductivity was measured by a DC four-terminal method. That is, after four platinum wire electrodes are attached to the fiber, they are fixed between a Mahler sheet and a Teflon (registered trademark) plate, a constant current is passed between the two outer platinum wires, and the two inner platinum wires are The resulting potential difference was measured with a voltmeter with high input impedance.

(Examples 1-3 and Comparative Examples 1-3)
Obtained by the method shown in US Pat. No. 4,453,393, 14.0% by mass of polyparaphenylenebenzobisoxazole having an intrinsic viscosity of 24.4 dL / g measured with a methanesulfonic acid solution at 30 ° C. and polyphosphoric acid ( A polymer dope having a phosphorus pentoxide content of 83.17% by weight was used for spinning. The dope for spinning is added after a predetermined amount of phthalocyanine copper to the polymer dope in the polymerized dope so that the content with respect to the polymer mass becomes the content shown in Table 1, and mixed uniformly, and then allowed to pass through a metal mesh filter medium. And filtered. Next, after kneading and defoaming with a biaxial kneader, the pressure is increased, the spinning dope temperature is maintained at 170 ° C., spinning is performed at 170 ° C. from a spinneret having a hole number of 166, and the humidity is adjusted to a temperature of 60 Cool the discharged yarn with a cooling nitrogen air at ℃, cool the discharged yarn to 40 ℃ by natural cooling, and then introduce it into the coagulation / extraction bath (30 mass% phosphoric acid aqueous solution adjusted to 30 ℃) And turned into yarn. Next, the yarn was wound around a gossette roll, washed at a constant speed and washed in a second extraction bath of ion-exchanged water, and then immersed in 0.1N sodium hydroxide solution for neutralization. Next, after immersing in a 10% by mass aqueous potassium iodide solution, it was washed with a water-washing bath, wound up, and dried in a drying oven at 80 ° C. until the moisture content contained in the fiber was 2% or less. The evaluation results of the obtained fiber are shown in Table 1.

Example 4
A fiber was produced in the same manner as in Example 2 except that phthalocyanine iron was used instead of phthalocyanine copper. The results of the obtained fiber are shown in Table 1.

  From Table 1, it can be seen that the polybenzazole fiber of the present invention exhibits higher electrical conductivity than the conventional polybenzazole fiber and is extremely excellent in strength properties.

The polybenzazole fiber of the present invention is a polybenzazole fiber having unprecedented electrical conductivity, and can achieve both high strength and conductivity, thus increasing the practicality as an industrial material and expanding the application field Is enormous.
That is, in addition to high-density and high-performance circuit board applications for mounting silicon chips, tension members such as cables, electric wires and optical fibers, tension materials such as ropes, rocket insulation, rocket casing, pressure vessels, and spacesuit strings Aircraft such as planetary exploration balloons, space materials, impact resistant materials such as bulletproof materials, cut resistant materials such as gloves, fire clothes, heat felt, plant gaskets, heat resistant fabrics, various seals, heat resistant cushions, filters, etc. Heat-resistant flame-resistant material, belt, tire, shoe sole, rope, hose rubber reinforcement, fishing line, fishing rod, tennis racket, table tennis racket, badminton racket, golf shaft, club head, gut, strings, sail cross, running shoes, Marathon shoes, spike shoes, skate shoes, basketball Athletic shoes such as shoes, volleyball shoes, bicycles for competition (running) and their wheels, road racers, pistracers, mountain bikes, composite wheels, disc wheels, tension disks, spokes, brake wires, transmission wires, for competition (running) Wheelchairs and their wheels, protectors, racing suits, skis, stocks, helmets, parasols and other sports-related materials, avance belts, friction materials such as clutch facings, various building material reinforcements and other rider suits, speaker cones, lightweight It can be used for a wide range of applications such as baby carriages, lightweight wheelchairs, lightweight nursing beds, lifeboats, and life jackets.

Claims (3)

A polybenzazole fiber comprising a phthalocyanine compound, having an electric conductivity of 1 (Ω · cm) ⁻¹ or more and a tensile strength of 4 GPa or more.   The polybenzazole fiber according to claim 1, wherein the content of the phthalocyanine compound is 5% by mass or more and less than 50% by mass.   A polymer dope containing polybenzazole, a solvent of the polybenzazole and a phthalocyanine compound is discharged from a spinneret, and after drawing to form a yarn, the obtained yarn is subjected to extraction treatment of the solvent, and further contains iodine. A method for producing a polybenzazole fiber, which is immersed in a liquid, washed with water and dried.