Formaldehyde Treatment of Partially Swollen Cotton

Abstract

Two processes for producing wash-wear cotton fabrics by treatment with formaldehyde are described. One of these processes consists of reacting the fabric in a wet swollen condition in an aqueous solution of formaldehyde and hydrochloric acid. This fabric has good wet wrinkle recovery only and is therefore referred to as the Form-W process. It has good strength retention and is suitable for line-drying after washing. The other process consists of reacting the fabric in a wet, partially swollen condition in a solution of acetic acid,. water, hydrochloric acid, and formaldehyde. It is referred to as the Form-D process because the fabrics have good dry (as well as wet) wrinkle recovery. These fabrics are suitable for either line-drying or tumble-drying. It is very important in both processes that the fabrics be well mercerized if adequate strength is to be re tained. Softeners also improve the tearing strength. Laboratory and pilot-plant appli cations are described, and data on the physical properties of the fabrics presented. Reaction rates of the Form-D process at various temperatures are given. Also, preliminary work on other solvents and catalysts is discussed briefly. Cross-linking with formaldehyde at various degrees of fiber swelling is discussed briefly from a theoretical standpoint.

Structural Features of Cotton Treated by Pad-Dry-Cure, Mild-Cure, Poly-Set, and Wet-Fix Processes

“…Lines of similar lows slopes as those for the poly-set and wet-fix processes have been obtained in two cases in preceding studies {19]: (1) for the cotton crosslinked with CH20 by the slow, room-temperature, vapor-phase process of Guthrie ( 19 j and (2) for the &dquo;wet-cure&dquo; product from the reaction of CH20 with cotton in a particular aqueous reagent mixture ( 3,19].…”

“…The reagent residues which are extracted in the Cuene may include resin which was simply deposited in cotton and those units of reagent which were attached to the cellulose through fragments of the initial reagent which bear a proton or methylol group on the N atom. Within this frame of reference, the high fraction of nonextractable reagent residues from the cotton crosslinked by the wet-fix process appears attributable to linkages of the It is possible, however, that nonextractable reagent residues may be due to structures of the reagent residues which result in Cuene insolubility regardless of the nature of the linkage to the cellulose.3 3 The high levels of residues extractable from the cottons crosslinked by the pad-dry-cure process (59%), by the mild-cure process ( 71 % ) , and by the poly-set process (73%) suggest that most of the reagent residues are present as deposited resin and/or are attached through N atoms bearing protons or methylol groups.…”

X-ray Crystallinity of Bleached and Crosslinked Cottons

“…The currently used formaldehyde crosslinking of cotton in a water-swollen state imparted wet recovery only. We carried out an experiment of finishing bleached cotton printcloth through the formaldehyde solution with a view to determine line drying qualities of the printcloth and observed wrinkle-free line drying of the printcloth indicative of excellent wet recovery [22]. These different performance characteristics (of line drying and tumble drying) have been attributed to different distributions of crosslinks in the accessible regions of the fiber.…”

Degree of Cross-Linking and Fiber, Yarn, and Fabric Properties 1

“…yarns, and fabrics were measured after cross-linking these materials to various extents by the U.S.D.A. Form D and Form ~'V ~ processes [ 1,Rl. In the. case of fihers.…”