Creped Tissue Web Structure for Smoothness and Bulk Retention
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Solution Overview
Problem
Creped tissue sheets face challenges in achieving high bulk and softness while maintaining roll firmness, as they tend to lose bulk during winding and have low surface smoothness, making it difficult to produce premium tissue products with desired attributes.
Innovation Solution
The use of high-topography papermaking fabrics and registered creping techniques to produce creped tissue webs with low surface roughness and high bulk, resulting in smooth and firm rolled tissue products with improved surface properties and bulk retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If creped tissue sheets are produced with high basis weight to increase thickness and softness, then softness is improved, but sheet bulk decreases because bulk is achieved by molding into the papermaking fabric which is decreased by increasing basis weight
Solution Approach 1:
The patent changes the surface parameters of the papermaking fabric by introducing high topography features with controlled peak heights and spacing. This allows the fabric to provide sufficient molding for bulk retention while enabling creping to achieve smoothness, resolving the contradiction between softness and bulk at low basis weights
Solution Approach 2:
The patent applies preliminary creping treatment to the tissue sheet before winding. This pre-creping action smooths the sheet surface and sets the bulk structure in advance, preventing bulk loss during subsequent winding operations and maintaining both smoothness and bulk in the final product
2Volume of stationary object
If the tissue sheet is wound loosely to increase roll bulk, then roll bulk is improved, but roll firmness decreases making the roll unappealing to consumers
Solution Approach 1:
The patent modifies the tissue sheet parameters by creating a smooth surface with controlled bulk through high topography fabric and creping. This allows the sheet to maintain its bulk structure during winding, enabling tight winding with high roll firmness while preserving adequate roll bulk
Solution Approach 2:
The patent applies preliminary creping to smooth the sheet surface and establish bulk structure before winding. This pre-treatment prevents bulk compression during winding, allowing the roll to achieve both high firmness and adequate bulk
3Manufacturing precision
If conventional creping techniques are used to achieve smoothness, then surface roughness is reduced, but sheet bulk is lost
Solution Approach 1:
The patent changes the fabric topography parameters to create peaks with heights of 0.020-0.060 inches spaced 0.040-0.120 inches apart. This specific parameter configuration allows creping to smooth the surface while the fabric peaks maintain sheet bulk, resolving the contradiction between smoothness and bulk retention
Data Source
AI summary
Creped tissue webs having low surface-roughness and high sheet bulk are disclosed. Specifically creped, single ply tissue web having a single wire probe mean deviation of MIU (MMD) of less than about 0.040 and a sheet bulk of greater than about 12 cc/g are disclosed. Additionally creped, multi-ply tissue web having a single wire probe mean deviation of MUI (MMD) of less than about 0.035 and a sheet bulk of greater than about 10 cc/g are disclosed.