PROCESS FOR THE CONTINUOUS PRODUCTION OF A FIBRE WEB DENSIFIED BY HEAT-SHRINKAGE AND APPARATUS FOR THE PERFORMANCE OF THE PROCESS

摘要

1325555 Densified webs; finishing fabrics KALLE AG 15 Sept 1970 [17 Sept 1969] 44011/70 Headings D1R and D1S A fibre web containing heat shrinkable fibres is densified by being advanced and exposed on one or both sides to heat first applied at opposite points on the web edges and then applied progressively, from each of the points in a similar manner towards the web axis until the whole web width is heated. The web may be cooled in the unheated web zone beyond the opposed points in the direction of advance of the web. Web 1, advancing through the nips of roller pairs 2 and 5, is heated by tubular heating elements 3a which have nozzles spraying heating fluid, e.g. hot water, hot gas or steam, onto the web. The web may be heated to a temperature of from 60‹C to 150‹C, and preferably from 70‹C to 120‹C, and may be alternatively heated by one or more electric elements. The web is cooled by triangular element 4, which may contain a liquid cooling medium, such as water, at a temperature of from 0‹C to 25‹C, and which may have the shape of an isosceles triangle having an apex angle of from 30‹ to 90‹. Heating elements on opposite sides of the web may occupy congruent areas, as may the opposed cooling elements. The web may consist entirely of heat-shrinkable synthetic fibres such as polyethylene, polypropylene, polyvinylidene chloride, polyacrylonitrile or polyamide, and particularly polyethylene terephthalate. Alternatively, the web may include a proportion of non-heat-shrinkable fibres such as natural fibres, e.g. natural or regenerated cellulose, or synthetic high-polymers such as polyamide, polyethylene terephthalate or polyacrylonitrile.