TH43754A - A printed sheet of paper that wrinkles when wet. - Google Patents

Abstract

DC60 (19/01/43) Wet-crumpled paperboard is a low-density sheet of paperboard with improved tensile strength, tear strength, and thickness. The distribution of the densed areas corresponds to the distribution of the wavy areas on the drying material. Generally, these densed areas should be distributed so that the distance between at least some of the densed areas is less than or equal to the length of the longest fiber in the finishing material (e.g., pulp fibers and/or other fibers) used in making the paperboard. Wet-crumpled paperboard is removed from the Yankee dryer at a dryness between 45 and 65% and then transferred to the post-drying section of the papermaking machine. The post-drying material is pressed into the wet-crumpled base sheet to transfer the post-drying characteristics to the sheet and to create improved tensile strength, tear strength, and thickness. The wet-crumpled base sheet is pressed into the post-drying material. Drying is done using a partial clamping process before the fiber sheet reaches 70% dryness. As soon as the wet base fiber sheet initially contacts the drying sheet, it should remain on the drying sheet without any changes in its alignment between the wet base fiber and the drying sheet until the base fiber is at least 80% dry. The wet-crumpled paper sheet has a low density and improved tensile strength, tear strength, and thickness. The distribution of the densed areas corresponds to the distribution of the crimped areas on the drying sheet. Generally, these densed areas should be distributed so that the distance between at least some of the densed areas is less than or equal to the length of the longest fiber in the finishing material (e.g., pulp fibers and/or other fibers) used in making the paper sheet. The wet-crumpled paper sheet is removed from the Yankee dryer when it reaches between 45 and 65% dryness and is then transferred to the subsequent drying range of the papermaking machine. The post-dryer sheet is pressed into the wet base sheet to transfer the post-dryer's contour characteristics to the base sheet and to create improved tensile strength, tear strength, and thickness. The wet base sheet is pressed into the post-dryer sheet using a partial clamping mechanism before the base sheet reaches 70% dryness. Immediately upon contact with the post-dryer sheet, the wet base sheet should remain in alignment with the post-dryer sheet until the base sheet is at least 80% dry.

Claims (18)

1. A paper fiber sheet with improved tensile strength, tear strength, and thickness, consisting of: - a low-density, wet-wrinkled paper fiber sheet; and - densely packed areas on the fiber sheet so that the distance between at least one of the densely packed areas is less than or equal to the length of the longest fiber in the material used to make the paper fiber sheet. 2. The paper sheet of claim 1, where the fiber fragments are concentrated in densely packed areas. 3. The fiberboard of claim 1, whereby the various chemicals added to the finish are concentrated on one surface of the finished fiberboard. 4. The fiberboard of claim 1, whereby the chemicals added to the finish are moved and thus concentrated on one surface of the finished fiberboard at denser areas. 5. The paper fiber sheet of claim 1, whereby such paper fiber sheet is a base fiber sheet which is a low-density paper for paper towels and toilet paper. 6. The paper sheet of claim 5, whereby such paper sheet is a base sheet of low-density paper with improved tensile strength, tear strength and thickness. 7. A process for producing low-density wet-wrinkled fiberboard with improved tensile strength, tear strength, and thickness, comprising: - Removing the wet-wrinkled fiberboard from a Yankee dryer with a dryness between 45 and 65%; - Pressing the wet-wrinkled fiberboard onto the subsequent dryer sheet to transfer the subsequent dryer's structure using a partial clamping mechanism before the fiberboard reaches 70% dryness; and - Maintaining the wet-wrinkled fiberboard on the subsequent dryer sheet without altering the alignment between the wet-wrinkled fiberboard and the drying sheet until the wet-wrinkled fiberboard reaches at least approximately 80% dryness. 8. The procedure for claim 7 is that wet-wrinkled paper sheets are removed from a Yankee dryer when their dryness is between approximately 50 and approximately 60%. 9. The procedure of claim 7, where a sheet of paper fibers that has been wrinkled when wet is pressed into a sheet of material and subsequently dried using a partial clamping mechanism, until the dryness of such fibers is between approximately 50 and approximately 60%. 10. The procedure of claim 7, whereby the pressing step is accomplished by utilizing hard pressing rollers which are rotated by soft rollers in such a way that the hard pressing rollers come into contact with the subsequent drying material and press the subsequent drying material sheet into the base fibrous sheet which is rotated or supported by the soft rollers. 11. Procedure of Claim 10, where the hard pressing roller is a steel roller and the soft pressing roller is a rubber roller. 12. The procedure of claim 7 whereby soft pressing rollers come into contact with the post-drying material sheet and press the post-drying material sheet into a base fiber sheet which is supported or cushioned by hard rollers. 13. The procedure of claim 7 is that soft pressing rollers come into contact with the post-drying material sheet and press the post-drying material sheet into a base fiber sheet which is supported or held by the drying drum. 14. The process of claim 13, whereby the drying tanks are selected from Yankee dryers, heated cores, steam tanks and combinations thereof. 15. Procedure of claim 10 whereby a pressing procedure is performed so that the pressure on the rollers is sufficient to produce a clamping force of approximately 10 to approximately 400 pounds per square inch. 16. Procedure of claim 15 whereby a pressing procedure is performed so that the pressure on the rollers is sufficient to produce a clamping force of approximately 10 to approximately 100 pounds per square inch. 17. Procedure of claim 15 whereby a pressing procedure is performed so that the pressure on the rollers is sufficient to produce a clamping force of approximately 20 to approximately 50 pounds per square inch. 18. Procedure of Claim 7, whereby the paper fibers, which are wrinkled when wet, remain on the drying material until they are approximately 95% dry.