Creped Tissue Web Design for High Bulk and Surface Smoothness
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Solution Overview
Problem
Conventional creped through-dried tissue sheets face challenges in achieving high bulk and softness while maintaining roll firmness, especially when wound into rolls, as they tend to lose bulk due to compressive forces during winding, leading to a trade-off between roll bulk and consumer-desired firmness.
Innovation Solution
The use of high-topography papermaking fabrics and registered creping techniques to produce creped tissue webs that are both smooth and have high bulk, maintaining desirable firmness and roll bulk by optimizing surface properties such as MIU and SMD, and adjusting fiber furnish and processing conditions to achieve low lint levels and increased tensile strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional creping techniques are used to produce creped tissue webs, then the tissue sheets achieve softness and flexibility, but the bulk is significantly reduced due to compressive forces during winding and converting
Solution Approach 1:
The invention changes the physical parameters of the tissue web by controlling the basis weight and using high-topography papermaking fabrics to maintain high bulk even at low basis weights. The registered creping technique modifies the creping parameters to preserve bulk while achieving smoothness and softness.
Solution Approach 2:
High-topography papermaking fabrics act as an intermediary between the tissue web formation and the final product properties. These fabrics create a structured surface that maintains bulk while enabling smoothness, serving as a mediator that resolves the contradiction between bulk retention and surface quality.
2Strength
If the basis weight of the tissue sheet is increased to achieve higher softness perception, then softness improves, but achieving high sheet bulk becomes more challenging
Solution Approach 1:
The invention changes the approach by achieving high softness perception not through increased basis weight but through optimized surface properties (smoothness and bulk) at low basis weights, fundamentally altering the parameter relationship between weight and softness.
Solution Approach 2:
The invention applies local quality by creating high bulk and smoothness in specific regions of the tissue web through high-topography papermaking fabrics, allowing softness to be achieved through localized structural properties rather than uniform increases in basis weight.
3Volume of moving object
If the tissue roll is wound loosely to increase roll bulk, then roll bulk increases, but the roll firmness decreases making it unappealing to consumers
Solution Approach 1:
The invention changes the fundamental parameter relationship by achieving high roll bulk and high roll firmness simultaneously through optimized tissue web properties (smoothness, bulk, and strength) that allow tight winding without bulk loss, breaking the traditional trade-off between these properties.
Solution Approach 2:
The invention applies preliminary action by pre-optimizing the tissue web properties (bulk, smoothness, and strength) before winding, so that the web is prepared in advance to maintain its structure during winding, preventing bulk loss and ensuring firmness without requiring loose winding.
4Shape
If heavy calendaring is applied to achieve smoothness, then surface smoothness improves, but the bulk of the tissue sheet is lost
Solution Approach 1:
High-topography papermaking fabrics serve as an intermediary that creates surface smoothness during web formation without requiring post-formation calendaring. The fabric structure imprints a smooth pattern on the web while preserving bulk, eliminating the need for bulk-reducing smoothing operations.
Solution Approach 2:
The invention applies preliminary action by achieving surface smoothness during the web formation stage through high-topography fabrics, before any bulk-reducing operations could occur. This preliminary smoothing prevents the need for subsequent calendaring that would compromise bulk.
Data Source
Figure 1
AI summary
The present disclosure relates to creped tissue webs that demonstrate low surface-roughness and high sheet bulk. The present disclosure relates to a 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. The present disclosure also relates to a 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.