J.G. Frick

Effects of Cross-Linkage in Wrinkle-Resistant Cotton Fabrics

The cross-linking of cellulose in cotton fabric with three wrinkle-resistance finishing agents has been investigated. The three agents used were dimethylol urea, dimethylol ethyleneurea, and formaldehyde. With all three compounds, maximum crease recovery angles are obtained with a substitution of 0.04-0.05 cross links per anhydroglucose unit. As crease recovery angles increase, the elongation and permanent set caused by an 8-kg. tensile load on a 1-in. fabric strip decreases. Permanent set approaches zero near 135° warp crease recovery. Changes in the load-elongation curves indicate elastic modulus increases as crease recovery angles increase. Treatment of fabric to the same crease recovery angles with the three compounds reduces tearing and breaking strengths to different extents. The differences are due to different amounts of cellulose degradation caused by the aciclic catalyst systems and not to the structure of the cross links.

Flame-Resistant Cotton Fabrics: An Emulsion Treatment Using an Organic Phosphorus- Bromine Polymer

Flame-resistant cotton fabrics have been prepared by treatment of the fabric with an aqueous emulsion of an organic polymer, prepared from bromoform and triallyl phosphate. The finish is durable to repeated laundering, and when applied with proper plasticization to fabrics of 8-9-oz weight does not materially change other textile properties. The treatment may be applied on conventional textile finishing equipment.

Hydrolysis Resistance of Cross-Linking Finishes for Cotton

The relative acid and alkali stabilities of various nitrogenous finishes for cotton have been compared. The effect the groups attached to the carbonyl and the substituents on the amido nitrogen exert on the electron density of the amido group has been related to acid and alkali resistance. The finishes studied included those derived from urea. cyclic ureas, carbamates, and carhoxylic amides. In general, the groups exerting strong electron-attracting force on the amido group will increase the acid stability of the resulting finish and decrease the alkali resistance, and the groups which are strong electron donors increase the alkali stability and decrease the acid resistance.

Electronic Effects of Substituent Groups upon Acid Hydrolysis of Amido-Methylol Finishes on Cotton

The results of a study on the susceptibility to acid hydrolysis of the products from the reaction of amido-methylol compounds with cotton are reported. A correlation was found between electron displacement and ease of hydrolysis. Substituent groups in the amido-methylol compounds play an important role in the electron displacement. Electron- releasing groups attached to either the amido nitrogen or the carbonyl carbon facilitate acid hydrolysis; electron-attracting groups hinder hydrolysis, Various hydrolysis mech anisms are considered for explaining the observed inductive and resonance effects. A mechanism wherein initial electrophilic attack is at the ethe al oxygen a fission of the link with cellulose is through carbonium ion formation appears co pletely satis factory in explaining the observed facts.

Studies on the Distribution of Cross-Links in Wrinkle-Resistant Cottons1

The properties of untreated cotton, cotton acetylated to various degrees, and partially deacetylated cottons were examined before and after cross-linking treatments to obtain information on the distribution of cross-links in wrinkle-resistant cottons. The study showed that the cellulosic hydroxyl groups that are most reactive with dimethylol ethyleneurea are acetylated first. Similarly, deacetylation released the most reactive groups first. Electron micrographs showed that interlamellae cross-links (cross-links between growth layers) in the cotton fiber occur when there is improvement in dry crease recovery, but the interlamellae cross-links are not essential for improvement in wet crease recovery. Wet recovery (without dry) was imparted by intermicrofibril crosslinks.

Adducts of Glyoxal and Amides as Finishing Agents for Cotton1

Adducts of glyoxal with urea, 1,3-dimethylurea, and methyl carbamate can be used as formaldehyde-free finishing agents for wrinkle-resistant, shrinkage-resistant, or durable-press cotton. These adducts are less effective than the usual methylolamide nnisbing agents and often cause discoloration. However, only small amounts of formaldehyde need be added with the glyoxal to increase the effectiveness and reduce the discoloration noticeably. The agents are more likely to be of value on cotton- polyester blends where less crosslinking is required.

Analysis of Agent Migration during Durable-Press Treatments of Knitted Cotton Fabric

A method was developed to quantitatively assess lateral agent migration during controlled drying of knitted cotton fabrics impregnated with cellulose crosslinking agents. The influence of inorganic salts and a nonionic surfactant on migration was investigated. Reasons for this influence are indicated. Relative migration rates were established and results were applied to phenomena occurring during conventional drying conditions. Results are correlated with qualitative evidence of migration from resistance of crosslinked fabrics to direct dyes.

A Compounded Flame Retardant for Cotton Fabrics

A combination of two existing flame retardants, THPC and the bromoform-triallyl phosphate polymer, produces a flame-retardant finish for cotton which is superior to that of either finish alone. Fabrics 8 oz. or heavier are made highly flame-resistant. The finish is durable and employs a single treating bath with a simple finishing procedure.

Formation of Cellulose Ethers in Water-Repellency Treatment of Cotton with Stearamidomethyl pyridinium Chloride:

Stearamidomethylpyridinium chloride reacts with cellulosic hydroxyl groups to produce a stear amidomethyl ether of cellulose. Substitutions of 1 stearamidomethyl group per 150 anhydro glucose units have been obtained. The permanent water-repellency obtained on treatment of cotton fabrics with amidomethylpyridinium salts is due to this reaction.

Retention of Swelling Ability in Cotton Cross-Linked with High-Temperature Curing

The cross-linking of cotton fabric with several N-methylol finishing agents in combi nation with an additive, the dimethyl ether of tetraethylene glycol, was investigated in an effort to obtain wrinkle-resistant and wash-wear cotton fabrics that retain an ability to swell with water. By proper adjustment of the concentration of this additive in the pad bath, it is possible to obtain finished fabrics with moisture regains equal to or even greater than untreated cotton, while maintaining good wrinkle resistance and wash-wear appearance. Wet crease recovery is slightly increased and dry crease recovery is slightly decreased by the use of the additive. Chlorine resistance and the relationship of breaking strength to crease recovery are unaffected. The inclusion of this additive in the treating bath formulation appears to alter hoth the length and distribution of the cross-links formed.