A pilot plant evaluation was made to compare the effects of roller ginning and saw ginning on the fiber, yarn, and fabric properties and processing performance of Pima S-1 cotton. Combed and carded yarns made from roller- and saw-ginned cotton and sewing thread and fabric made from combed lots of each stock were evaluated. The fabrics were compared in the grey and after finishing (singeing, mercerization, scouring, bleaching, dyeing, and Sanforize treating). It was found that, within the limits of this study, the general processing efficiency of the roller-ginned cotton was better than that of the saw-ginned cotton. The method of ginning had no appreriable effect on the strength, uniformity, or elongation at break of combed yarns, but carded yarns spun from roller-ginned cotton were significantly stronger than those spun from saw-ginned stock. Combed yarns spun from the roller- ginned cotton were better in appearance than those spun from the saw-ginned stock. There were no significant differences in the physical properties of sewing thread pro duced from combed saw- or roller-ginned cotton. Fabrics produced from combed cotton ginned by both methods were approximately equal in tearing strength, but the saw-ginned cotton produced fabric that, in some cases, had a lower elongation and breaking strength. There were no significant differences in abrasion resistance between the fabrics before finishing, but the results for abrasion resistance of the finished fabrics were inconclusive. The fabric woven from the saw-ginned cotton contained consider ably more neps than that woven from the roller-ginned cotton. Since this type of cotton is generally used for the production of fine quality yarns and fabrics, it was concluded that saw-ginned extra long staple cottons would not be suitable for these uses. Also, due to the greater amount of waste during processing and poorer spinning performance of the saw-ginned cotton, processing costs would be higher and possibly offset any savings in ginning costs.

The reported results compare the yarn properties of a high-strength (11.5 Pressley Index) Interspecies cotton with those of five other cottons having a comparatively wide range of fiber properties. The cottons were processed alike on conventional processing equipment into 18/1, 36/1, and 72/1 carded yarns using a range of twist multipliers from 2.75 to 5.75. The sliver and roving made from each cotton were measured for uniformity and the yarns were tested for uniformity, appearance, and strength. It was found that yarns made front the Interspecies cotton were as strong as those made from the much longer and finer Karnak cotton and stronger than those made from the other cottons. The Interspecies and Karnak yarns were about equal in uniformity with both being more uniform than the other control yarns. A limited statistical analysis of yarn breaking strength data indicated that fiber strength is more important to yarn strength than either fiber fineness or length.

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.