Embossed Multi-Ply Tissue Structure for Higher Bulk Absorbency
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Solution Overview
Problem
Conventional wet pressing in paper manufacturing results in tissue products with reduced bulk and absorbency due to compaction during the dewatering process, while alternative methods like through-air-drying are energy-intensive and costly.
Innovation Solution
An embossing pattern is applied to tissue sheets, specifically a regular and continuous pattern on the back-most ply and a decorative pattern on the top-most ply, with emboss elements of defined aspect ratios and sizes, to increase the bulk and absorbency of tissue products, which can be used with conventional wet press or through-air-dried webs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If conventional wet pressing is used to dewater the web, then production cost and energy consumption are reduced, but the bulk and absorbency of the tissue product deteriorate
Solution Approach 1:
The embossing pattern segments the continuous web into discrete raised elements and recesses, creating localized volume increases throughout the sheet structure. This segmentation allows bulk enhancement without requiring uniform compression relief across the entire sheet, maintaining energy efficiency while improving absorbency through increased surface area and void spaces.
Solution Approach 2:
The embossing process introduces a third dimension to the otherwise flat compressed sheet by creating raised elements that protrude from the sheet plane. This dimensional change increases the effective volume and caliper of the tissue product without requiring additional material or energy-intensive processing, directly addressing the bulk deterioration caused by wet pressing.
2Use of energy by stationary object
If conventional wet pressing is used to dewater the web, then production cost is reduced, but the absorbency of the tissue product deteriorates
Solution Approach 1:
The embossing pattern creates a porous structure with raised elements and intervening recesses that increase the void volume within the sheet. This porous architecture provides additional pathways and spaces for liquid absorption, enhancing absorbency without requiring the high energy input of alternative dewatering methods. The patterned structure facilitates capillary action and liquid distribution throughout the tissue product.
Solution Approach 2:
By adding vertical relief through embossing, the tissue product gains additional three-dimensional space for liquid accommodation. The raised elements create localized reservoirs and increase the effective surface area available for liquid contact, thereby improving absorbency while maintaining the energy-efficient conventional wet pressing process.
3Volume of stationary object
If through-air-drying is used instead of conventional wet pressing, then bulk and absorbency are improved, but energy consumption and production cost increase
Solution Approach 1:
The embossing process creates a physical copy or replica of a desired three-dimensional pattern on the tissue sheet surface. This copied structure mimics the bulk characteristics of through-air-dried products by introducing raised elements and void spaces, achieving similar absorbency and softness properties without requiring the energy-intensive through-air-drying process itself.
Solution Approach 2:
The embossing process changes the physical parameters of the tissue sheet by introducing controlled variations in thickness, surface area, and void volume through the embossed pattern. These parameter changes—specifically increased caliper and surface area—enhance bulk and absorbency properties to levels comparable to through-air-dried products, while the underlying conventional wet pressing maintains low energy consumption.
Data Source
AI summary
Products having improved caliper, sheet bulk and absorbency and methods for making those products are described. The method comprises producing a multi-ply product having different emboss patterns on each ply where the emboss patterns are made up of emboss elements having an aspect ratio of from about 1 to about 2.