| 摘要 |
1,188,654. Producing polyester slub yarns. GLANZSTOFF A.G. 11 April, 1967 [27 April, 1966 (2)], No. 16587/67. Heading B5B. [Also in Division D1] Polyester yarn varying in denier along its length (slub yarn) is produced by stretching an unstretched polyester yarn at a stretch ratio which is 60 to 80% of the stretch ratio at which it must be stretched in order to break when further stretched so that its length is increased by 20%, using a snubbing pin having a diameter of from 15 to 60 mm. and maintained at a temperature which is within the range of 60‹ to 105‹ C., preferably 65‹ to 85‹ C. The ratio of the tension in the yarn travelling from a feed roll to the snubbing pin to the tension in the yarn travelling from the snubbing pin to the draw roll is within the range 1:1À5 and 1:1À4 and the tension in the yarn travelling from the snubbing pin is maintained at a value within the range 0À2 to 1À1 grams per denier. The yarn may be spun at a speed of 800 to 1200 metres per minute at the draw-off roll, the yarn may be stretched at a stretch ratio within the range 2À5:1 to 3À1:1, and the snubbing pin may be maintained at a temperature within the range 65‹ to 85‹ C. The snubbing pin may have a matt chrome surface and a diameter of 25 to 40 mm. The ratio of the yarn tension may be within the range 1:1À9 to 1:2À6 and the tension in yarn travelling from the snubbing pin to the draw roll is from 0À45 to 0À9 g./den. A polyester slub yarn produced according to the invention may have an elongation at break of 30 to 80%, preferably 35 to 65%, a shrinkage of 20 to 50% when immersed in boiling water, and may have 15 to 35, preferably 20 to 30 slubs per metre, the distance between adjacent slubs or thicker portions of the yarn being 0À5 to 8, preferably 0À8 to 6 cm. The thicker and thinner portions of the yarn are dyeable to different extents. The ratio of the denier of the portions of the yarn of minimum denier to that of the portions of the yarn of maximum denier may be between 1:1À1 and 1:3À5, preferably between 1:1À2 and 1:2À8.
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