Paper manufacturing process
View Patent ↗A method of making soft, strong, high bulk tissue is disclosed. The method includes pre-conditioning a wet web by straining the wet web in the cross-machine direction prior to transferring the wet web to a throughdrying fabric. The pre-conditioned web provides improved sheet softness and conforms more readily to the surface contour of the throughdrying fabric, thereby creating greater caliper (bulk) in the resulting dried sheet. The bulk is maintained during a subsequent creping step by maintaining the dried sheet in registration with the throughdrying fabric when the dried sheet is applied to the surface of the creping cylinder.
1. A method of making a paper sheet comprising:
(a) depositing an aqueous suspension of papermaking fibers onto a forming fabric to form a wet web;
(b) dewatering the web to a consistency of about 20 percent or greater;
(c) transferring the dewatered web to a three-dimensional transfer fabric having substantially continuous machine-direction ridges having a height of from about 0.4 to about 5 millimeters, a ridge width of about 0.5 millimeters or greater and a cross-machine direction ridge frequency from about 1.5 to about 8 per centimeter, whereby the wet web is molded to the surface contour of the transfer fabric and strained in the cross-machine direction;
(d) transferring the web to a throughdrying fabric, whereby the resulting molding-strained web is conformed to the surface contour of the throughdrying fabric;
(e) throughdrying the web to about 7 weight percent moisture or less while supported by the throughdrying fabric to form a paper sheet;
(f) transferring the sheet to a creping cylinder while maintaining registration with the throughdrying fabric; and
(g) creping the sheet.
2. The method of claim 1 wherein the degree of cross-machine direction molding strain imparted by the transfer fabric is about 2 percent or greater.
3. The method of claim 1 wherein the degree of cross-machine direction molding strain imparted by the transfer fabric is about 5 percent or greater.
4. The method of claim 1 wherein the degree of cross-machine direction molding strain imparted by the transfer fabric is from about 2 to about 20 percent.
5. The method of claim 1 wherein the degree of cross-machine direction molding strain imparted by the transfer fabric is from about 5 to about 20 percent.
6. The method of claim 1 wherein the degree of cross-machine direction molding strain imparted by the transfer fabric is from about 5 to about 15 percent.
7. The method of claim 1 wherein the degree of cross-machine direction molding strain imparted by the transfer fabric is from about 10 to about 15 percent.
8. The method of claim 1 wherein the web is dewatered to a consistency of from about 20 to about 40 percent.
9. The method of claim 1 wherein the web is dewatered to a consistency of from about 25 to about 35 percent.
10. The method of claim 1 wherein the dewatered web is rush-transferred from the forming fabric to the transfer fabric.
11. The method of claim 1 wherein the speed of the transfer fabric is substantially the same as the speed of the throughdrying fabric.
12. The method of claim 1 where the web is throughdried to 5% moisture or less.
13. The method of claim 1 where the web is throughdried to 3% moisture or less.