Multi-Ply Tissue Embossing Segmentation Bulk Softness
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Solution Overview
Problem
There is a need in the paper products industry to impart embossing designs to through-air dried webs without compromising their physical properties or manufacturing efficiency, particularly for high bulk, molded tissue webs.
Innovation Solution
The method involves providing the two outermost plies of a multi-ply tissue product with different embossing patterns, specifically a first pattern with line emboss elements and a second pattern with dot emboss elements, to achieve enhanced bulk and softness while maintaining aesthetic appeal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wet-pressing is used to dewater the web, then water removal efficiency is improved, but web thickness and bulk are reduced
Solution Approach 1:
The patent divides the tissue product into multiple plies (layers) with different embossing patterns. The multi-ply structure allows the product to maintain bulk while achieving aesthetic design goals, as each ply can be independently formed and embossed without excessive compression
Solution Approach 2:
Different embossing patterns are applied to different plies - the first ply receives a first embossing pattern while the second ply receives a second embossing pattern. This local differentiation allows each layer to contribute differently to the overall bulk and aesthetic properties
2Shape
If embossing is applied to a dry web, then design patterns are achieved, but hand feel becomes gritty and absorbency decreases
Solution Approach 1:
The embossing process is made dynamic by applying different embossing patterns to different plies at different stages. The first ply is embossed with a first pattern, then the second ply is embossed with a second pattern, creating a dynamic multi-layered surface structure that maintains softness while providing design elements
Solution Approach 2:
The tissue product is constructed as a composite of multiple plies with different embossing patterns. This composite structure combines the aesthetic benefits of embossing with the functional benefits of multiple layers, maintaining hand feel and absorbency while achieving design goals
3Volume of moving object
If UCTAD process is used to maintain high bulk, then web resiliency is improved, but embossing definition deteriorates
Solution Approach 1:
The embossing process is segmented into multiple steps applied to different plies. By embossaing the first ply with a first pattern and the second ply with a second pattern, the system achieves defined embossing on each layer while maintaining the overall bulk of the multi-ply structure
Solution Approach 2:
The first ply is embossed with a first embossing pattern before the second ply is added and embossed with a second pattern. This preliminary embossing action ensures definition is achieved on the first ply while the second ply's embossing enhances the overall structure without compromising the defined patterns already present
4Shape
If patterned through-air drying fabrics are used to create design elements, then design motifs are achieved, but air permeability is reduced
Solution Approach 1:
Instead of using a single patterned fabric that compromises air permeability, the patent segments the design function across multiple plies. Each ply can be formed on different fabrics, allowing open-patterned fabrics to be used for better air permeability while still achieving design elements through the combination of multiple plies with different embossing patterns
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 results in tissue products with improved bulk, softness, and visual appeal, achieving a basis weight of 20-60 gsm and a bulk greater than 15 cubic centimeters per gram, while maintaining geometric mean tensile strength and tissue softness.
Implementation Method 1
the wet web is transferred to a permeable through-air-drying fabric around an open drum and non-compressively dried by passing hot air through the web while in intimate contact with the fabric
Implementation Method 2
embossing the patterned web to impart a first embossed pattern on the web and provide a first embossed tissue ply
Data Source
AI summary
Embossed, multi-ply tissue products having consumer preferred physical properties and an aesthetically pleasing appearance such as a first tissue ply having a molded topographical pattern and a first embossed pattern comprising a plurality of embossed elements disposed thereon and a second tissue ply having a molded topographical pattern and a second embossed pattern comprising a plurality of dot emboss elements disposed thereon. The multi-ply tissue products generally have improved sheet bulk, such as a sheet bulk greater than about 15 cubic centimeters per gram (cc/g), and improved softness, such as an Average TS7 less than about 12.0 and more preferably less than about 11.0, such as from about 10.0 to about 12.0. The foregoing Average TS7 values may be obtained at a product geometric mean tensile strength (GMT) from about 800 to about 1,200 g/3″.