Yarn Processing Research Articles

Acrylonitrile in the Textile Industry

The rapid development of acrylonitrile as an industrial organic chemical during the past twenty years is reviewed and noted. Its reactivity with materials, such as cellulose, starch, wool, etc., which play a dominant role in the textile industry is discussed. The properties of the products obtained in these eyano‐ethylation reactions are considered, and some possible industrial applications of the products suggested. Finally a number of worthwhile uses of polyacrylonitrile and of copolymers containing acrylonitrile and other vinyl monomers are noted, with special reference to their outstanding value in the production of the comparatively new group of fully synthetic fibres known collectively as the acrylics. The properties of these fibres are commented on, and their value in certain applications is postulated. Brief mention is made also of the processing and dyeing of yarns and fabrics made from these fibres.

The Effect of Bottom Front Roll Run-Out in Spinning on Yarn Quality and Processing Performance

Measurement of bottom front roll run-out at every spinning stand position in a typical mill indicates that only a small percentage of the stands have run-outs that are exces sively high. It was found also that square neck jointed rolls in the two plants studied have higher roll run-outs than screw neck jointed rolls. A reasonable explanation for this is that the square neck jointed rolls generally receive rougher handling. since con siderable force is required when separating or putting together the sections of the rolls on the spinning frame. Periodic irregularities are introduced in the yarn by eccentric bottom front rolls which lower the quality of the yarn being produced. With increases of bottom front roll run- out from 0.000 in. to 0.010 in., the following properties of 31 1 warp yarn were affected to the extent shown: As the roll run-out increased, the pattern on yarn appearance boards became more dis tinct. Analysis of the yarn properties indicated that yarn quality was appreciably lowered at bottom front roll run-outs in excess of 0.0055 in. A study of the processing performance of the yarn produced at various bottom front roll run-outs indicates that yarns produced at high roll run-out positions are more difficult to process in spooling and weaving. In this study, there was an increase of 12% in the number of breaks in spooling as the bottom front roll run-out increased from ranges of 0.000-0.003-0.006 in. and higher. With these same ranges of roll run-outs, warp stops in weaving increased 48% when the weavability of the yarn produced at low roll run-out positions was compared with yarn produced at high roll run-out positions in spinning. The appearance grade of 80 X 80 print cloth, woven with filling yams produced at various roll run-out positions, was found to decrease with increases in bottom front roll run-outs. All graders that ranked the fabrics selected the fabric having the highest roll run-out as being the worst fabric in the group. However, no correlation was found be tween the appearance grade of 110 X 58 broadcloth woven with warp yarn produced at different bottom front roll run-outs in spinning.

CORROSION PROBLEMS IN Dyeing and Finishing Works

Wherever corrosion occurs it can be the cause of many difficulties and much frustration of effort, but it is believed that in no type of works can corrosion be so wasteful of materials and have so adverse an effect on output as in those works where textile materials are bleached, dyed, printed and finished. This can be readily understood when it is recognised that in the processing of textile yarns, fabrics and garments the results of corrosion not only influence the working of a machine so that this may break down and need repair or replacement, but the products of corrosion may become transferred to the textile material so as to interfere with the desired effects of the processing and thus cause the material to be seriously weakened or acquire some characteristic of colour or handle detrimental to its use or consumer appeal. The following article indicates the complexity of corrosion problems that can occur.

Evaluation of Yarn Properties and Processing Performance of Pima S-1 Cotton

Results are reported of a pilot plant evaluation of Pima S-1 cotton using an Egyptian variety, Karnak, and an American-Egyptian variety, Pima 32, as controls. The three cottons were processed alike on conventional equipment into a range of relatively fine single- and 2-ply yarns. Certain organizational details were varied within limits to aid in the evalution of the processing performance of the three cottons, and to determine the contributions each cotton made toward product quality. Each cotton was divided into three lots which were carded at 4, 6, and 8 lb/hr, respectively. Each lot was then combed, with 15 and 18% noils being removed. Twist- strength relationships were determined by spinning the yarns with a range of twist multipliers from 3.00 to 4.00 in increments of 0.25; draft-strength relationships were determined by spinning the yarns with a range of drafts from 14 to 53, using the twist multiplier found previously to produce maximum strength. The effect of the method of creeling was determined by spinning the same yarn number from a series of hank rovings both single and double creeled. Evaluation was made of gain in strength of 2-ply over single yarns using the same twist multiplier in both single and ply yarns. Also, an assessment was made of the response of these three cottons to three conditions of mercerizing and to subsequent dyeing. An analysis was made of opening-, picking-, and carding-waste percentages and of the uniformity of slivers and yarns. Yarn quality was determined by measuring skein and single-strand strengths, elongation, and appearance, and from the coefficient of variation of the strength values and Uster uniformity tester measurements. It was found that, within the limits of this study, the general processing performance of the Pima S-1 was equal to that of the Karnak and Pima 32 cottons. Regardless of the organizational variables used in the evaluation, the Pima S-1 cotton produced yarns of better appearance and uniformity than did the other two cottons. Also, yarns made from Pima S-1 were stronger than those made from Karnak, and were generally equal in strength to yarns made from Pima 32. Double creel produced stronger and more uni form yarns than did single-creel spinning for all the cotton varieties tested. The per formance of Pima S-1 in 2-ply constructions was equal to that of the two control cottons. The general response of Pima S-1 to mercerizing and to subsequent dyeing was slightly better than that of the other cottons.