Texture Subtractive Patterning for Soft, Absorbent Tissue Design
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Solution Overview
Problem
Current papermaking processes, such as wet-pressing and through-air drying, face challenges in creating tissue products with both high bulk and design elements without compromising absorbency, softness, and manufacturing efficiency, as traditional embossing methods often result in gritty, stiff products with decreased absorbency.
Innovation Solution
A method involving a textured fibrous structure is passed through a nip to compress and subtract a portion of the web's texture, creating a design element with a design element plane between the surface and bottom planes, allowing for aesthetically pleasing designs without increasing caliper or bulk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wet-pressing is used to remove water from the web, then dewatering efficiency is improved, but web bulk and absorbency are reduced
Solution Approach 1:
The web is divided into pattern areas and non-pattern areas, with only the non-pattern areas subjected to compression. This segmentation allows selective removal of texture in design areas while preserving bulk in other areas, resolving the contradiction between dewatering efficiency and bulk retention.
Solution Approach 2:
Different regions of the web are treated differently: pattern areas receive compression to remove texture and improve dewatering, while non-pattern areas maintain their original texture and bulk. This local differentiation allows the web to have both efficient dewatering in pattern areas and high bulk in non-pattern areas.
2Manufacturing precision
If traditional embossing is used to apply design elements, then design definition is improved, but hand feel becomes gritty and absorbency decreases
Solution Approach 1:
Instead of adding material or compressing the entire web, the invention extracts or removes texture only in the specific pattern areas where design elements are desired. This selective removal achieves clear design definition without the harmful side effects of traditional embossing that compress the entire web surface.
Solution Approach 2:
Traditional embossing adds compression to create design elements, but this invention inverts the approach by removing texture through selective compression of non-pattern areas. This inverse approach achieves design definition while preserving the soft, absorbent qualities of the web in the pattern areas.
3Volume of moving object
If through-air drying is used to avoid compression, then web bulk is maintained, but design elements cannot be effectively created
Solution Approach 1:
The web is segmented into pattern and non-pattern areas, allowing the non-pattern areas to be compressed for dewatering while pattern areas maintain bulk. This segmentation enables both bulk retention and effective design element creation in the same web.
Solution Approach 2:
Different compression levels are applied to different regions: non-pattern areas receive compression for dewatering, while pattern areas maintain their uncompressed, bulky state. This local quality differentiation allows the web to simultaneously achieve good bulk and well-defined design elements.
4Manufacturing precision
If patterned through-air drying fabrics are used to create design elements, then design motifs are provided, but air permeability is reduced and manufacturing efficiency decreases
Solution Approach 1:
Instead of using patterned fabrics that reduce overall air permeability, the invention extracts texture only in specific non-pattern areas after the web is formed. This approach creates design elements without the need for patterned drying fabrics, thereby maintaining high air permeability and manufacturing efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the creation of tissue products with visually distinct design elements that are soft, absorbent, and maintain high bulk, while avoiding the inefficiencies and texture issues associated with traditional embossing.
Implementation Method 1
passing the textured web through a nip to compress a portion of the web and subtract a portion of the textured structure
Data Source
AI summary
The present application provides a method of manufacturing a patterned tissue product comprising a textured background surface, and a design element wherein the design element is formed by removing a portion of the textured background. The method comprises the steps of (a) providing a tissue web having a textured top surface lying in a surface plane and a bottom surface lying in a bottom plane wherein there is a z-directional height difference between the surface plane and the bottom plane; (b) conveying the web through a first nip created by a first receiving roll and a pattern roll having a plurality of protuberances forming a design pattern; (c) conforming a portion of the web to the protuberances; and (d) conveying the web into a second nip formed between the pattern roll and a second receiving roll to form a patterned tissue product having a design element corresponding to the plurality of protuberances, the design element lying in a design element plane that is between the surface plane and the bottom plane. The textured surface provides the tissue with an overall background pattern that is typically visually distinct from the design element imparted thereon. The method may further comprise the step of applying a papermaking additive or water to the conformed portion of the web via an applicator roll between step (c) and (d). The pattern roll is generally a hard and non-deformable roll, such as a steel roll. The first receiving roll has a hardness greater than 40 Shore (A), such as from 40 to 100 Shore (A). The second receiving roll may have a smooth or non-smooth surface, and the pressure applied at the second nip is greater than 30 pli, such as from about 50-250 pli.