Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Patent
1995-01-05
1996-10-08
Edwards, N.
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
428397, 428399, 264160, 264147, D02G 300
Patent
active
055629865
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELDS
The present invention relates to novel polytetrafluoroethylene (PTFE) fibers excellent in intermingling property, cotton-like materials containing those fibers and a process for preparation thereof.
BACKGROUND ARTS
In recent years, non-woven fabrics comprising synthetic fibers, by making the best use of characteristics of those fibers, are extending their applications into various fields, such as clothing materials, medical materials, engineering and building materials, and materials for industrial use.
Among them, non-woven fabrics containing PTFE fibers are excellent in heat resistance, chemical resistance and abrasion resistance, and are expected to be further developed as highly functional non-woven fabrics.
Cotton-like PTFE materials being made into the non-woven fabrics are gathered PTFE fibers, and so far have been made in such manners as mentioned below:
The process for producing PTFE filaments is roughly classified into the following two processes. method comprises extrusion spinning of a viscose binder, and the like containing PTFE particles, and then sintering to obtain the filaments having a circular section. Major problems of that method are such that a binder remains as a carbonaceous residual after sintering, the obtained PTFE filaments are colored in a dark brown, and that even if the carbonaceous residual is oxidized to be discolored, an original purity cannot be maintained. comprises stretching of fibers obtained by slitting a PTFE film to a desired width. A problem of this method is that the smaller the slit width is, the more easily the fibers are broken at the time of stretching.
Both PTFE fibers obtained by the methods (1a) and (1b) have a low friction coefficient and a high specific gravity inherent to the PTFE, and therefore are not intermingled sufficiently with each other even if having been crimped. (JP-B-22621/1975) making a sheet-like material therefrom by paper making process (U.S. Pat. No. 3,003,912 and JP-B-15906/1969).
The method of the above-mentioned U.S. patent is to cut PTFE rod obtained by a paste extrusion, to a short length and to apply a shearing force to obtain fibrous PTFE powder.
JP-B-15906/1969 discloses a method for making fibers by applying a shearing force to the PTFE powder.
Any of the fibrous powder obtained by the above-mentioned methods can be made up to a sheet-like material by paper making process but cannot be made into a non-woven fibric by the use of a carding machine, needle punching machine, or the like as they are short in fiber length and in the form of a pulp.
An object of the present invention is to provide the PTFE fibers excellent in intermingling property and cotton-like materials containing those fibers.
Another object of the present invention is to provide a process for obtaining cotton-like PTFE materials, which are staple fibers (relatively short fibers), directly from a uniaxially stretched long film of PTFE, without making multi-filaments (a large number of continuous fibers).
DISCLOSURE OF THE INVENTION
The present invention relates to the PTFE fibers and the cotton-like materials containing those fibers, which can be obtained by opening a uniaxially stretched article of molded PTFE by a mechanical force.
It is preferable that the length of the PTFE fiber of the present invention is 5 to 150 min.
It is also preferable that the PTFE fibers of the present invention have a branched structure, fineness of the fibers is 2 to 200 deniers, the number of crimps is 1 to 15/20 mm and a section of the fibers is not uniform.
In the present invention, the shape of the section being not uniform means that the shape of the section of the fibers has no regularity and differs from S each other, and it can be said in more detail that the section of the fiber of the present invention has rather few complicated unevenness, and in most cases, is square-shaped and is in a shape resembling a cracked stone. There are many cases where flat fibers as shown in FIG. 13 (.times.50) are contained in a large ratio, though it is actually depe
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Asano Jun
Chaen Shinichi
Inoue Osamu
Kusumi Toshio
Tanaka Osamu
Daikin Industries Ltd.
Edwards N.
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