System and method for controlling curl in multi-layer webs
First Claim
1. A web handling system for producing a multi-layer web, the web handling system comprising:
- a curing section configured to cure a coating applied to a web of indeterminate length to form a multi-layer web; and
a web stretching section configured to biaxially stretch the web in both a machine direction and a cross-machine direction, the web stretching section at least partially overlapping with the curing section, such that the web is biaxially stretched by the web stretching section while the coating is cured by the curing section,wherein the web stretching section is configured to stretch the web not beyond an elastic limit thereof such that when the web is released by the web stretching section, the web relaxes back to an unstretched state,wherein the web stretching section includes a tenter system including;
a roller rotatable about an axis of rotation, the web wrapping around the roller;
an endplate coupled to the roller and rotatable about the axis of rotation, the endplate being oriented at a non-perpendicular angle with respect to the axis of rotation, the endplate including an outer circumferential surface positioned to contact the web;
a groove defined in the outer circumferential surface of the endplate, the groove extending circumferentially; and
a belt dimensioned to be received within the groove, such that a lateral end of the web is gripped between the groove and the belt as the web is moved through the web stretching section,wherein the endplate is tilted with the non-perpendicular angle with respect to the axis of rotation such that the endplate includes a first point at which the endplate is spaced a maximal lateral distance from the roller and the web wrapping around the roller reaches a point of maximal cross-machine directional strain when the web passes over the first point, and the curing section is positioned adjacent to the first point.
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Abstract
A system and method for controlling curl in multi-layer webs. The method can include providing a coated web, curing the coating to form a multi-layer web, and stretching the web during curing of the coating. Some coatings shrink at least partially when cured such that curing the coating induces a strain in the multi-layer web. Stretching the web occurs during curing to induce an opposing strain that at least partially counteracts the strain induced by curing to form a multi-layer web having a desired curvature. The system can include a curing section configured to cure the coating, and can further include a web stretching section, which can be located proximate the curing section and can be substantially coincident with the curing section, such that the web is stretched while the coating is cured.
128 Citations
10 Claims
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1. A web handling system for producing a multi-layer web, the web handling system comprising:
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a curing section configured to cure a coating applied to a web of indeterminate length to form a multi-layer web; and a web stretching section configured to biaxially stretch the web in both a machine direction and a cross-machine direction, the web stretching section at least partially overlapping with the curing section, such that the web is biaxially stretched by the web stretching section while the coating is cured by the curing section, wherein the web stretching section is configured to stretch the web not beyond an elastic limit thereof such that when the web is released by the web stretching section, the web relaxes back to an unstretched state, wherein the web stretching section includes a tenter system including; a roller rotatable about an axis of rotation, the web wrapping around the roller; an endplate coupled to the roller and rotatable about the axis of rotation, the endplate being oriented at a non-perpendicular angle with respect to the axis of rotation, the endplate including an outer circumferential surface positioned to contact the web; a groove defined in the outer circumferential surface of the endplate, the groove extending circumferentially; and a belt dimensioned to be received within the groove, such that a lateral end of the web is gripped between the groove and the belt as the web is moved through the web stretching section, wherein the endplate is tilted with the non-perpendicular angle with respect to the axis of rotation such that the endplate includes a first point at which the endplate is spaced a maximal lateral distance from the roller and the web wrapping around the roller reaches a point of maximal cross-machine directional strain when the web passes over the first point, and the curing section is positioned adjacent to the first point. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification