The United States of America As Represented by the Secretary of

Timothy A Calamari, Jr

Robert J Harper, Jr

Ruth R Benerito

Lawrence Y Yatsu

Sidney P Schreiber

Novel cellulosic fiber with improved resistance to abrasion and increased permeability to chemicals characterized by highly stable crystalline cellulose III and cellulose IV forms is disclosed. Cellulose selected from either fiber, yarn, fabric, cotton, or mercerized cotton is treated with ammonia vapors at from about ambient to 140.degree. C. and from about 100 psi to 1700 psi for sufficient time to alter the interatomic planar distances and produce stable crystalline cellulose III polymorph. Crystalline cellulose III can also be immersed in ethylenediamine and then boiled in dimethylformamide to completely convert the III to cellulose IV.

Stable crystalline cellulose III polymorphs

Novel cellulosic fiber with improved resistance to abrasion and increased permeability to chemicals characterized by highly stable crystalline cellulose III and cellulose IV forms is disclosed. Cellulose is selected from either fiber, yarn, fabric, cotton, or mercerized cotton treated with ammonia vapors at from about ambient to 140.degree. C. and from about 100 psi to 1700 psi for sufficient time to alter the interatomic planar distances and produce stable crystalline cellulose III polymorph. Crystalline cellulose III can also be immersed in ethylenediamine and then boiled in dimethylformamide to completely convert the III to cellulose IV.

Flame resistance sufficient to enable cellulose containing materials to pass modern flammability standards has been imparted to these materials by application of an aqueous solution containing a methylol phosphorus compound followed by heat drying to about 15% or less moisture content, and finally by polymerizing the phosphorus material in the cellulose containing material by any one of several indirect aqueous ammonia curing techniques. The invention provides an improved process for flame proofing cellulosic materials which avoids the use of ammonia gas during the cure and which results in little or no loss in tensile strength or in an undesirable change in hand. Cellulosic textiles treated by this process retain their flame resistant properties after repeated laundering.

Transfer techniques for producing flame retardant cotton fabrics

Cotton fabric and cotton-blended fabric which has been sensitized by treatments with methylol phosphorus compounds and heat-dried have been subjected to a 'wet-transfer' technique which transfers a formaldehyde donor along with an aqueous ammonium hydroxide solution, thus providing an improved process for imparting flame retardance to fibrous cellulosic materials.

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Metairie, LA, United States of America

Timothy A Calamari, Jr