Claims
- 1. In a method for preparing crosslinked cellulosic fibers wherein said fibers are treated with a chemical crosslinking agent, individualized, dried and cured, the improvement which comprises carrying out the drying and the curing in a pressurized vessel providing turbulent flow so as to entrain said treated fibers in superheated steam, said drying being carried out with pressurized steam at an initial temperature ranging from about 140.degree. to about 350.degree. C. and a pressure of 10-105 psia; and curing of said dried and treated fibers being carried out in a pressurized vessel providing turbulent flow so as to entrain said treated fibers in superheated steam and render them anfractuous, said curing being carried out with pressurized steam at an initial temperature ranging from about 140.degree.-350.degree. C. at a pressure of 10 to 105 psia.
- 2. The process of claim 1 wherein said pressurized steam in steps a) and c) is essentially 100% superheated steam.
- 3. The process of claim 2 wherein step a) is carried out at a temperature of from 200.degree. C. to 300.degree. C.
- 4. The process of claim 3 wherein step a) is carried out at a pressure of from 20 to 90 psia.
- 5. The process of claim 2 wherein step c) is carried out at a pressure of from 20 to 90 psia.
- 6. The process of claim 5 wherein step c) is carried out at a temperature of from 200.degree. to 300.degree. C.
- 7. The process of claim 1 wherein said chemical crosslinking agent used to treat the fiber prior to drying and curing is applied in an amount sufficient to produce a standard bulk of at least about 3.4 cc/g when incorporated into British Handsheets when incorporated at a level of 15% by weight according to Tappi Standards but using a pressing pressure of 15 psig.
- 8. The process of claim 7 wherein the crosslinking agent is citric acid.
- 9. The process of claim 7 wherein the crosslinking agent is 1,3-dimethyl-4,5-dihydroxyimidazolidione.
- 10. The process of claim 7 wherein the crosslinking agent is 1,3-dimethyl-4,5-dihydroxyethyleneurea.
- 11. The process of claim 8 wherein a catalyst or coreactant is used.
- 12. The process of claim 9 wherein a catalyst or coreactant is used.
- 13. The process of claim 10 wherein a catalyst or coreactant is used.
- 14. The process of claim 11 wherein said catalyst or coreactant is sodium hypophosphite.
- 15. The process of claim 12 wherein said catalyst or coreactant is magnesium chloride.
- 16. The process of claim 13 wherein said catalyst or coreactant is magnesium chloride.
Parent Case Info
This application is a continuation-in-part of U.S. application Ser. No. 08/017,037 filed Feb. 12, 1993. This invention is concerned with cellulosic fibers exhibiting improved resilient bulking both in the wet and dry states and also with absorbent structures incorporating said cellulosic fibers. More specifically, this invention is concerned with a novel process for producing individualized anfractuous crosslinked cellulosic fibers, where the novelty resides in heating crosslinker treated fibers by entraining them in turbulent superheated steam at particular pressures and temperatures, individualizing said fibers and then curing the fibers while entrained in turbulent superheated steam at elevated temperatures and pressures.
US Referenced Citations (9)
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
17037 |
Feb 1993 |
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