| 摘要 |
<p>1,085,983. Hollow polytetrafluoroethylene filaments. DAIKIN KOGYO KABUSHIKI KAISHA. Dec. 4, 1964 [Dec. 6, 1963], No. 49400/64. Heading B5B. A hollow filament consisting of a solid ethylene in which the area of the wall of a tetrafluoroethylene polymer containing at least 70% by weight of polytetrafluoroethylene enclosing an axial cavity along the whole length of the filament, the relative volumes of the cavity and the wall being such that the cavity portion of the total cross-sectional area of the filament is 5 to 90% may be made by wet spin. ning a mixture of a viscose and an aqueous dispersion of the tetrafluoroethylene polymer into a coagulating bath maintained at a temperature within the range 50‹ to 100‹'C. and consisting of an aqueous solution of either sulphuric acid of 6 to 60% by weight concentration, or con. taining not more than 6% sulphuric acid and not less than 5% of a water-soluble sulphate, or containing 1 to 30% by weight of hydrochloric acid or 1 to 50% by weight of nitric acid, the spinning solution containing 0À4 to 8% by weight of cellulose and tetrafluoroethylene polymer in such a concentration as to constitute 70 to 99% of the combined weight of cellulose and polymer in the solution. The tetrafluoroethylene polymer may be a homopolymer or a copolymer of tetrafluoroethylene with hexafluoropropylene, trifluorochloroethylene or vinyl chloride containing in each case at least 70% by weight of tetrafluoroethylene. The filaments produced in the wet spinning step consist of a mixture of tetrafluoroethylene polymer particles and regenerated cellulose and after washing and drying are heated to a temperature sufficiently high to cause the particles of polymer to coalesce and the cellulose to decompose.</p> |
