GB1521183A - Process and apparatus for stretching a non-woven web of an orientable polymeric material - Google Patents

Abstract

1521183 Stretching fabrics E C A SCHWARZ 29 March 1976 [31 March 1975] 12521/76 Heading D1S A non-woven web 12 of orientable polymeric material is biaxially stretched by passing the web 12 into the nip 14 between rollers 16 having intermeshing peripheral corrugations extending parallel to the axes thereof to effect longitudinal stretching and passing the longitudinally stretched web 20 into the nip 24 between rollers 26 having intermeshing peripheral corrugations extending perpendicular to the axes thereof to effect transverse stretching. The web 12, Fig. 1, of staple fibres or continuous filaments, is fed from a roll 10 to the rollers 16 and is maintained against the lower roller 16 by press rollers 21. After passage through the nip 14, the web is stretched longitudinally by tension rollers 22 rotating with a peripheral velocity greater than that of the rollers 16. The web 20, Figs. 4 and 5, passes into the nip 24 and is held against the lower roller 26 by press rollers 30. The web 32 is stretched laterally by tenter chains or curved rolls 34 and is collected on a roll 36 rotating at the same peripheral velocity as the velocity of feed of the web 20 to the rollers 26. The longitudinal and lateral stretching steps may be repeated alternately through multiple passes. The grooves or corrugations on the rollers 16, 26 are sinusoidal in section and are as fine as possible to prevent the fibres breaking and the web losing tensile strength. Examples refer to biaxially stretching a randomly laid web of partially oriented polypropylene fibres, a spun-bonded web of continuous polyester fibres and a latex bonded randomly laid web of polyester fibres.