Abstract
The unrestricted shrinkage of balanced plied yarns and singles yarns in sodium hydroxide solution of mercerizing strength was found to increase with increasing twist; the extent of shrinkage and rate of increase were higher for singles yarns than plied yarns. Plied yarns developed high tensions faster than singles yarns when mercerization was carried out without shrinkage. If shrinkages of more than 15% to 20% are permitted, the tension developed is almost too low to measure. This indicates that for fabrics that shrink more than 20% the forces that may cause additional shrinkage are very small and easily restricted. Twist had only minor effects on the shrinkage of the 72 fabrics of varying warp ends per inch and different yarn structure used in the experiments. Also the stretch properties were similar. Calculations of filling tightness, expressed as filling cover factor, indicate that a maximum of approximately 16 can be obtained by the slack mercerization of fabrics for filling stretch if the fabric shrinks more than 20%. The conversion of cellulose I to cellulose II is more dependent on the temperature of the wash water than on the amount of unrestricted shrinkage or duration of immersion. To obtain additional shrinkage in any fabric of a selected weight, it is apparently necessary to use weaves that promote increases in fabric thickness.
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