M. Lipson

The Development of Washable Non-Iron Effects in Pure Wool Fabrics

The use of reducing agents for setting wool has been extended to give washable non-iron effects on pure wool fabrics. Initially this was accomplished by applying the Si-Ro-Set process to garments made from shrinkproofed wool. This led to flat setting of fabrics in the mill by applying a dilute solution of a reducing agent to the fabric fol lowed by immediate steaming on a blowing machine. When preceded by shrinkproofing, this method of setting gives excellent washable non-iron effects on pure wool fabrics. Garments made from fabric treated in this way showed satisfactory laundering and wear performance in practical trials.

The Mothproofing of Wool with Dieldrin

Dieldrin does not react with wool but, during treatment in aqueous emulsions, some of the insecticide penetrates the fibers. This small amount, sufficient to mothproof the wool, is not removed by the usual drycleaning solvents which do not cause swelling, but can be extracted completely by hot methanol or acetone. Dieldrin is gradually lost when treated wool is washed in soap solutions, but an initial application of 0.05% on the weight of wool gives a mothproofing effect which withstands machine washing for 3 hr. ASTM Standard Tests have been applied to wool containing 0.05% Dieldrin, and the insectproofing effect found to be fast (Class 3) to laundering, dry and wet cleaning, hot pressing, sea water, acid and alkaline perspiration, light, and rubbing. Dieldrin has been applied to large amounts of wool at various stages of processing: the results of these industrial trials are given. Treatment should preferably be in the final wet process, since some of the insecticide is removed by subsequent dyeing, bleaching, or milling. Application is preferred from the dyebath when dyeing is the final wet process.

Modification of Wool by the Application of Linear Synthetic Polyamides Part V: Pretreatment with Ethanolic Potassium Hydroxide

Ethanolic potassium hydroxide solutions in concentrations from 0.1% to 5.0% have been used to pretreat wool effectively for the application of N-alkoxymethyl polyamides to prevent felting shrinkage. The alcoholic alkali may be used purely as a pretreatment, or the alkali can be incorporated in the alcoholic resin solution. Even when the alkali pretreatment does not in itself reduce the felting shrinkage, effective shrinkproofing is obtained with less than 1% resin based on the weight of wool.

70—PROCESSING SOLVENT-DEGREASED WOOL

Experiments comparing the processing of solvent-degreased wool with that obtained by soap–soda scouring in several plants are described; it is shown that card and comb production rates considerably higher than normal are possible using solvent-degreased wool and a higher combing tear and a better top can be produced. At normal processing rates, the solvent-degreased wool gives 2 to 3% lower loss during carding and combing, much lower nep content, and much less fibre breakage. There is also a greater yield of clean wool from the solvent-degreasing method.

Stereoscan Microscopy of Chlorine/ Resin-Treated Wool

The scanning electron microscope (Stereoscan) has been used to study the surface modifications that occur during chlorine-resin shrinkproofing. Each stage of the treat ment causes a variety of clearly distinguishable changes in the fiber surface. After chlorination or neutralization, four types of surface topography occur, while the resin- treated fibers may be divided into two or three types, depending on the level of treatment. The main features of the chlorinated fibers are the rounding of the scale tip, together with the appearance of longitudinal striations in the cuticle, and a smooth region near the distal end of the scale. Further modifications occur during neutralization, the scale tips becoming more rounded and the surface generally more smooth.- When a high degree of shrink resistance is obtained, all the fibers are completely covered by a layer of resin which may be smooth or rough with thick ridges of resin along the scale tips. These resin layers remain intact even after severe washing for long times.

22—AQUEOUS JET SCOURING OF RAW WOOL PART III. PRELIMINARY PILOT-PLANT STUDIES

The effects of various factors on scouring efficiency have been investigated on a small jet-scouring machine with aqueous detergents. Optimum results were obtained with: (a) a contact time of 40–80 sec; (b) the lowest nozzle pressure adequate to achieve the desired cleaning effect; (c) detergent additions concentrated towards the later bowls; (d) sodium carbonate used in the first one or two bowls; (e) liquor temperatures above 65°C; and(f) polyoxyethylene nonylphenol detergents with 9–10 ethylene oxide groups per molecule.

110—WASHABLE NON-IRON FABRICS FROM WOOL

The flat setting of shrinkproofed wool can give washable, non-iron effects on pure wool fabrics. Setting, which consists of steaming fabrics containing 50% by weight of 1% sodium bisulphite solution for 5 min on a blowing machine, prevents surface distortion of the fabrics during subsequent washing. The effect of fabric structure on the results of treatment has been studied using seventeen specially woven worsted fabrics. All these cloths can be made satisfactorily shrink-resistant and set, the combined treatments also tending to increase wet wrinkle-recovery. However, wet wrinkle-recovery is not directly related to the non-iron property of treated fabrics. The shrink proofing and setting procedures have now been developed for industrial use, and methods of overcoming problems in dyeing, preventing stiffening during setting, and producing fabrics free from relaxation shrinkage are described. Difficulties in constructing washable, minimum-iron garments from treated fabrics are discussed, and recommendation...

52—AQUEOUS JET SCOURING OF RAW WOOL PART II: STUDIES OF LABORATORY-SCALE MULTI-STAGE SCOURING

The jet and conventional immersion methods of wool scouring have been further studied by means of aqueous detergent systems in a laboratory-scale, multi-stage apparatus. On a cost basis, both methods gave similar results with alkaline scour liquors, whereas the jet method was inferior with neutral liquors. Wool scoured through four alkaline stages by the jet method was not significantly weaker than wool scoured through four neutral stages by the immersion method.