Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Patent
1998-01-21
2000-03-07
Edwards, Newton
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
428395, D02G 300
Patent
active
060337788
DESCRIPTION:
BRIEF SUMMARY
DETAILED DESCRIPTION OF THE INVENTION
1. Technical Field
The present invention relates to an aromatic polyamide bristle, more particularly to an aromatic polyamide bristle having light weight and high strength and modulus as well as excellent chemical resistance and widely usable in various industrial fields such as tension member, fishing line and catheter.
2. Background Art
Nylon bristle and polyester bristle have been used widely as a polishing brush and fishing line owing to the high rigidity and abrasion resistance. A meta-type aromatic polyamide bristle is also in use as a polishing brush severely required to have high heat-resistance and abrasion resistance. However, these bristles have insufficient mechanical properties such as strength and modulus.
In contrast with the above, a para-type aromatic polyamide bristle has excellent mechanical properties represented by high strength, modulus and rigidity and, accordingly, the application field of the bristle is expected to be developable to industrial materials and leisure uses for the reinforcement of a rubber article such as tire or a plastic article. The conventional para-type aromatic polyamide bristle is, however, a poly-p-phenylene terephthal-amide bristle produced by the wet-spinning of an optically anisotropic solution (Japanese Patent TOKUHYOUHEI 4-500394) and has a problem of poor chemical resistance to acids and alkalis in spite of excellent rigidity, mechanical properties, heat-resistance, etc.
A thick-denier fiber made of a para-type aromatic polyamide is disclosed in Japanese Patent TOKKAIHEI 5-163610. The object of the invention is to improve the twist strength utilization factor for developing the application to industrial fields such as rope, hose and belt using a cord having high twist number by flattening the cross-section of the fiber to lower the geometrical moment of inertia and facilitate the twisting deformation in the twisting process. Accordingly, the thick-denier fiber having a single fiber fineness of 10 de or over disclosed in the invention is limited to those having extremely high flatness. Since the fiber has insufficient rigidity and is easily deformable by external force, such fiber can never be called as a bristle.
DISCLOSURE OF INVENTION
The object of the present invention is to provide a para-type aromatic polyamide bristle having excellent mechanical properties represented by high rigidity, strength and modulus and good heat-resistance and chemical resistance.
As a result of extensive investigation for achieving the above object, the inventors of the present invention have found that a fiber (especially represented by copoly-p-phenylene 3,4'-oxydiphenylene terephthalamide fiber) produced by the wet-spinning of an optically isotropic solution is needed to be drawn at high draw ratio after spinning, therefore, the extremely large -single fiber fineness of an undrawn fiber is necessary for getting a bristle having a single fiber fineness of 10 de or over and, as a result, the production of a bristle, having excellent mechanical properties such as strength and modulus, becomes difficult owing to the insufficient or non-homogeneous desolvation in spinning. On the contrary, the desolvation rate can be increased without generating defects in the fiber to enable homogeneous coagulation of even a bristle having large single fiber fineness and obtain an aromatic polyamide bristle having excellent chemical resistance by increasing the dope temperature and the coagulation bath temperature and lowering the concentration of the good solvent in the coagulation bath.
The aromatic polyamide bristle of the present invention achieving the above object is produced from an optically isotropic solution and has a single fiber fineness of 10 to 200 de, a flatness of 3 or less and mechanical properties characterized by a tensile strength of 15 g/de or above, an elongation at break of 4.0% or less and an initial modulus of 500 g/de or above.
BEST MODE FOR CARRYING OUT THE INVENTION
The aromatic polyamide constituting the bristle of th
REFERENCES:
patent: 4075172 (1978-02-01), Ozawa et al.
patent: 5246776 (1993-09-01), Meraldi et al.
patent: 5378538 (1995-01-01), Makino et al.
Kakihara Ryuichi
Noma Takashi
Edwards Newton
Teijin Limited
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