Multi-ply Tissue Products with Improved Cross-Machine Direction Properties
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Solution Overview
Problem
Current tissue manufacturing methods fail to balance cross-machine direction properties such as tensile strength, stretch, and modulus, resulting in products that are either weak or stiff, lacking both durability and softness.
Innovation Solution
The process involves transferring a partially dewatered tissue web to a highly structured transfer fabric that imparts strain in the cross-machine direction, followed by through-air drying, to create multi-ply tissue products with improved CD tensile energy absorption, stretch, and modulus without creping, achieving balanced physical attributes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If through-air drying process with textured fabrics is used to improve cross-machine direction properties, then CD stretch and CD modulus are improved, but CD tensile strength becomes weak (less than 600 g/3'')
Solution Approach 1:
The tissue web is divided into multiple plies (first ply and second ply) with different structural characteristics. The first ply is formed on a forming fabric with through-air drying to provide strength, while the second ply is formed on a molding fabric to provide softness and absorbency, achieving balanced CD properties through ply segmentation
Solution Approach 2:
Different regions of the tissue product have different properties: the first ply has higher tensile strength characteristics for durability, while the second ply has higher softness and absorbency characteristics, creating local quality differentiation to satisfy both strength and comfort requirements
2Ease of operation
If low CD modulus is achieved to reduce stiffness perception, then softness is improved, but CD tensile strength becomes insufficient (less than 600 g/3'')
Solution Approach 1:
The tissue is segmented into two plies with distinct functions: the first ply provides structural strength and durability, while the second ply provides softness and absorbency, resolving the contradiction between strength and softness through functional segmentation
Solution Approach 2:
The tissue product is a composite structure combining two different ply types with complementary properties, where the first ply contributes strength characteristics and the second ply contributes softness characteristics, achieving a balanced composite material with both durability and comfort
3Strength
If CD modulus is increased to avoid weak/flimsy appearance, then strength perception is improved, but softness and pliability are reduced
Solution Approach 1:
The tissue web is segmented into two plies where the first ply has higher CD modulus for strength and the second ply has lower CD modulus for softness, achieving a balanced composite with both high strength perception and softness
Solution Approach 2:
Different local regions (plies) have different mechanical properties: the first ply has high modulus characteristics for strength and durability, while the second ply has low modulus characteristics for softness and pliability, creating local quality differentiation
Data Source
AI summary
Provided are tissue webs, and products produced therefrom, that are generally durable, flexible and have improved cross-machine direction (CD) properties, such as CD tensile energy absorption (CD TEA), CD stretch and CD modulus. The inventive tissue products generally comprise multiple tissue plies, such as two or more plies, that have been prepared by through-air drying and more preferably by through-air drying without creping. Moreover, the plies may be produced in a through-air drying process that utilizes a transfer fabric positioned between the forming fabric and the through-air drying fabric where the transfer fabric imparts the nascent web with a high degree of CD strain.