Absorbent Sheets With Layered Softness And Caliper
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing paper products face challenges in achieving a balance between absorbency and softness, as techniques to enhance one property often compromise the other, and the papermaking industry seeks more economically efficient methods to produce products with higher bulk and comparable properties.
Innovation Solution
The development of a process to determine the planar volumetric index of structuring fabrics used in papermaking, which involves analyzing the contact area ratio and effective pocket volume to optimize the three-dimensional structure of paper products, allowing for improved absorbency, softness, and caliper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If calendering basesheets is used to increase softness, then the perceived softness of the products is improved, but the caliper of the basesheets is reduced
Solution Approach 1:
The invention divides the basesheet into multiple layers with different functions. The top layer is calendered to provide softness, while the bottom layer remains uncalendered to maintain caliper and absorbency. This segmentation allows each layer to optimize for its specific function without compromising the other properties.
Solution Approach 2:
The invention applies calendering only to specific regions of the basesheet (the top layer) rather than the entire sheet. This local quality approach ensures that softness is improved where it is needed for customer perception, while the uncalendered bottom layer maintains the caliper and absorbency properties.
2Strength
If wet and dry strength resins are added to improve underlying strength, then the wet tensile strength is improved, but the perceived softness is reduced
Solution Approach 1:
The invention segments the strength enhancement function to be performed by the uncalendered bottom layer rather than adding resins throughout the entire sheet. The bottom layer provides the necessary wet tensile strength through its structural integrity and bonding to the calendered top layer, eliminating the need for softness-reducing resins in the customer-contact layer.
Solution Approach 2:
The uncalendered bottom layer acts as an intermediary that provides structural strength and supports the calendered top layer. This intermediary layer bears the mechanical load and provides wet tensile strength, allowing the top layer to maintain softness without requiring strength-enhancing resins.
3Quantity of substance
If techniques are used to increase absorbency, then the absorbency of the products is improved, but the perceived softness is decreased
Solution Approach 1:
The invention segments the absorbency function to be performed by the uncalendered bottom layer, which has higher porosity and caliper to provide absorbency. The calendered top layer maintains softness for customer perception. This segmentation allows absorbency and softness to be optimized in different layers simultaneously.
Data Source
AI summary
A cellulosic sheet includes a single ply providing a first surface of the cellulosic sheet on one side and a second surface of the cellulosic sheet on a second side. The single ply has a caliper of at least about 130 mils/8 sheets, a basis weight of less than about 16 lbs/ream, and a dry machine direction/cross machine direction (MD/CD) tensile ratio of less than about 1.0.