Porous flame retardant acrylic synthetic fibers and a method for producing these fibers
AssigneesKanebo, Ltd., Kanebo Synthetic Fibers Ltd.
InventorsYoshikazu Kondo, Toshihiro Yamamoto, Takaji Yamamoto
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Abstract
Porous flame retarded acrylic synthetic fibers consisting of cellulose acetate and a modacrylic copolymer containing vinyl chloride and/or vinylidene chloride are produced by spinning an organic solvent solution of a polymer consisting of cellulose acetate and the above described modacrylic copolymer into a coagulation bath, primarily drawing the spun fibers at a draw ratio of 2.5.about.8.0, drying the water swelled fibers at 100.degree..about.180.degree. C. to a water content of no greater than 1.0% by weight and secondarily drawing the dried fibers under wet heat at a draw ratio of no greater than 3 times.
Claims10
A porous, flame-retardant, acrylic, synthetic fiber, in which the polymeric component of said fiber consists of a mixture of
- (A) from 2 to 50% by weight of cellulose acetate, and
- (B) from 50 to 98% by weight of a polymer material selected from the group consisting of
- 1. modacrylic copolymer consisting of from (i) 20 to 60% by weight of at least one of vinyl chloride and vinylidene chloride, (ii) less than 5% by weight of a copolymerizable monomer different from vinyl chloride, vinylidene chloride and acrylonitrile, and (iii) the balance is acrylonitrile, and
- 2. mixture of said modacrylic copolymer and an acrylic copolymer consisting of (i) from 5 to 30% by weight of monomer having the formula ##STR109## wherein R.sub.1 is H or CH.sub.3, X is selected from the group consisting of H, NH.sub.4, alkali metal and ##STR110## wherein R.sub.3 is H or CH.sub.3, and l and m are integers of from 0 to 50 and 0<l+m.ltoreq.50, (ii) at least 70% by weight of acrylonitrile and (iii) the balance is said copolymerizable monomer, with the proviso that the amount of said acrylic copolymer is not greater than 33% by weight, based on the total weight of said polymeric component of said fiber, said fiber having a surface area A of voids of not greater than 15 m.sup.2 /g, a porosity V of from 0.05 to 0.75 cm.sup.3 /g and the ratio of porosity V/surface area A being 1/30 or more, said fiber having mainly macrovoids formed by phase separation of said cellulose acetate and said modacrylic copolymer.
Dependencies are inferred from the claim text.