Process for drawing a web
AssigneeImperial Chemical Industries PLC
InventorsStephen J. Restorick, John P. Donnellan
Life of this patent
Estimating the term…
Abstract
A process and apparatus for producing a web achieves relaxation of the web in the machine direction during and/or after heat-treating, by changing the shape of the side edge of the web in the longitudinal plane from a substantially non-linear zone to a substantially linear zone.
Claims8
A process for producing a web comprising drawing the web in a machine direction and heat-treating the drawn web in a stenter, such that the side edge of the web in a longitudinal plane changes, during and/or after heat-treating, from a zone where the edge of the web is substantially non-linear to a zone where the edge of the web is substantially linear and the direction of movement of the web, in the non-linear zone, changes greater than two times and the internal angle formed by the web in changing the direction of movement in the non-linear zone is between 90.degree. and 170.degree., the web shrinking by at least 0.1% in the machine direction during and/or after heat-treating.
A process for producing a web comprising drawing the web in a machine direction and heat-treating the drawn web in a stenter, such that the side edge of the web in a longitudinal plane changes, during and/or after heat-treating, from a zone where the edge of the web is substantially non-linear to a zone where the edge of the web is substantially linear and the direction of movement of the web, in the non-linear zone, changes greater than two times and the angle formed by the web in changing the direction of movement is between 90.degree. and 170.degree., the web shrinking by at least 0.1% in the machine direction during and/or after heat-treating.
Dependencies are inferred from the claim text.