Production of high strength hollow rayon fibers
AssigneeInternational Paper Company
InventorEugene Costa, Jr.
Life of this patent
Estimating the term…
Abstract
High strength hollow rayon fibers or filaments which will recover their hollow configuration after being immersed in water and subsequently dried are provided by an in-line process whereby a viscose solution containing a blowing agent is extruded into an aqueous acid coagulating bath of relatively high acid concentration. The conditions of the process result in hollow filaments that are substantially irreversible since they remain hollow and do not collapse even after repeated washing and drying cycles. The hollow filaments also possess high strength nearly equivalent to that of high wet modulus rayon fibers. Modifiers may be employed in achieving this effect, but are not necessary.
Claims25
A process for producing hollow rayon fibers resistant to collapse after drying, which process comprises spinning a viscose solution containing alkali cellulose, a blowing agent selected from the class consisting of alkali-metal carbonates and bicarbonates, carbon disulfide, and ripened to a Salt Index of from about 6 to 12 cubic centimeters of sodium chloride, into an aqueous acidic coagulating bath containing from about 150 to 220 grams per liter of sodium sulfate, from about 120 to 160 grams per liter of sulfuric acid, and from about 30 to 80 grams per liter of zinc sulfate, and thereafter stretching the resulting hollow rayon fibers by between about 40 and 120%.
A process for producing hollow rayon fibers resistant to collapse after drying, which process comprises spinning a viscose solution containing alkali cellulose, a blowing agent selected from the class of alkali-metal carbonates and bicarbonates, and ripened to a Salt Index of from about 6 to 12 cubic centimeters of sodium chloride, into a first aqueous acidic coagulating bath containing from about 100 to 400 grams per liter of sodium sulfate, and from about 100 to 200 grams per liter of sulfuric acid and after stretching thereafter passing the resulting blown fibers into an aldehydic bath containing between about 5 grams and 60 grams per liter of an aldehyde, said aldehydic bath having a pH of from about 3.0 to 7.0.
A process in accordance with claim 16, wherein said viscose solution contains cellulose in an amount of from about 6 to 9% by weight on weight of viscose, alkali-metal hydroxide in an amount of from about 6 to 8% on weight of viscose and a viscosity of from about 90 to 140 poises.
Dependencies are inferred from the claim text.