GB407763A - Improvements in or relating to the manufacture of elastic rubber thread, cord, stripand the like - Google Patents

Abstract

407,763. Rubber threads and tapes. SOC. ITALIANA PIRELLI, and PESTALOZZA, U., 21, Via Fabio Filzi, Milan, Italy. Oct. 22, 1932, No. 29616. Convention date, June 4. [Class 70.] Rubber thread, cord, or small tube, is made by forming a parent length of unvulcanized rubber or of vulcanized latex coagulum containing a substantial proportion of the water of the dispersion, having a crosssectional form corresponding to that required in the final thread &c., drawing this length out, and setting it permanently in this form, with subsequent vulcanization, if necessary. Stretching may proceed by stages with intervening periods of rest. Permanency is obtained by heating during stretching or in the rest periods. A thick thread &c. 2 is passed once round a roll 1, and is stretched by being drawn on to a roll 5 driven at a higher speed. From roll 5 it passes to a drum 6 rotated at the same peripheral speed, and heated, e.g. by immersion in a bath 7, or internally by steam. The set thread passes to a roll 8, and is submitted to a second stage of stretching and setting on roll 9, and drum 10. It may pass through a third stage, or be batched on a roll 11. It is desirable to limit the stretch at any stage to half the elongation at break. The process is particularly applicable to threads &c. made by extruding heat sensitive latex through hot nozzles according to Specifications 284,608, 292,964, 330,520, [all in Class 70], or 351,012. Specification 376,973 also is referred to.