Tissue rolls having variable cross-machine direction properties
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Tissue manufacturers face challenges in producing rolled tissue products with high bulk and firmness while maintaining acceptable cost and processing efficiency, as increasing basis weight typically compromises roll bulk and firmness.
Innovation Solution
A calendering process that varies physical properties across the cross-machine direction of tissue webs by using a patterned calender roll with distinct patterns, allowing for regions of differing sheet caliper, bulk, and smoothness, enabling improved processing and packaging without compromising product quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the basis weight of the tissue sheets is increased, then roll firmness is improved, but roll bulk decreases
Solution Approach 1:
The patent applies local quality by creating regions of different basis weights within the same tissue web. Specifically, the tissue web contains a first region with a first basis weight and a second region with a second basis weight that is different from the first basis weight. This allows different portions of the roll to have different firmness characteristics, enabling the roll to achieve both high bulk (through lighter regions) and good firmness (through heavier regions) simultaneously.
2Volume of moving object
If the tissue roll is wound loosely to increase roll bulk, then roll bulk is improved, but roll firmness deteriorates
Solution Approach 1:
The patent resolves this contradiction by implementing local quality through variable basis weight regions. The tissue web is constructed with at least two regions having different basis weights, allowing the roll to be wound loosely for high bulk while specific heavier regions provide the necessary firmness to prevent deformation during processing and packaging.
3Strength
If the tissue roll is wound tightly to improve roll firmness, then roll firmness is improved, but roll bulk decreases
Solution Approach 1:
The patent applies local quality by creating heterogeneous basis weight distribution within the tissue web. Regions with higher basis weight provide firmness support, allowing the roll to maintain good firmness even when wound loosely to achieve high bulk, eliminating the need for tight winding.
Data Source
AI summary
The invention provides calendered tissue webs and products produced by passing a tissue web through a calender nip created by a patterned roll having a first pattern and a second pattern thereon and a substantially smooth roll. As the web is transported through the nip it is subjected to variable calender loads that impart variable cross-machine (CD) direction properties to the resulting calendered web. CD properties that may be varied according to the present invention include sheet caliper, sheet bulk and surface smoothness. The variable CD property may be preserved in the web as it is further converted, such as winding about a core, resulting in tissue products having physical properties that vary along at least one dimension of the product.