| 摘要 |
1,103,485. Hot stretching synthetic elastomeric filaments. COURTAULDS Ltd. 8 June, 1965 [9 June, 1964], No. 23809/64. Heading B5B. Synthetic elastomeric threads are heated to a temperature of at least 130‹ C. and simultaneously stretched at least 200%, e.g. 200 to 600% while they are passing between two thread-storage devices the speeds of which are adjusted to give the desired degree of stretching over a period of time not exceeding 1 minute. The threads leaving the second storage device are allowed to relax freely and are collected in a form substantially free from tension. The threads may be stretched over a distance of from 2 to 4 feet and the rate of feed of thread to the first storage device may be 10 to 200 feet per minute giving dwell times in the heating zone of from about 24 seconds to fractions of a second. The percentage stretch is calculated as the percentage increase in length based on the original length of the thread. The heating of the thread between the storage devices may be effected by passing the thread through a jacketed capillary tube, e.g. a tube about <SP>1</SP>/ 32 inch i.d., which is heated by passing high pressure steam through the jacket. The thread may be heated by running it in contact with an electrically heated plate. The temperature of the heating device may be as high as 230‹ C. In the examples, the threads used are polyester-based elastomeric threads of 420 and 700 denier obtained from an adipic acid-ethylene glycol-propylene glycol polyester reacted with an excess of diphenyl methane diisocyanate and extruded into aqueous ethylene diamine. The term " thread " is said to include filaments and yarns and the expression: an " elastomeric thread " is defined as meaning a thread having an elongation at break of at least 150%, a tensile recovery of 90% or more and a " stress decay " of less than 30%. The process of the present invention is a modification of that of Specification 916,287 in which the minimum treating time mentioned is 5 minutes.
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