Structured Papermaking Fabric for Tissue Bulk and Strength

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Solution Overview

Problem

Tissue products face challenges in achieving a balance between softness, strength, bulk, and aesthetics, as traditional manufacturing methods often compromise on these properties, particularly when calendering through-air dried tissue webs, which can degrade strength and bulk.

Innovation Solution

Non-compressively dewatering tissue webs using a structured papermaking fabric with elements of specific height (0.4 to 0.7 mm) to enhance z-directional properties, resulting in improved compression energy, bulk, and aesthetics, allowing for high calender loads without significant loss of sheet bulk or strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of stationary object

If through-air drying is used to increase sheet bulk, then bulk is improved, but softness deteriorates due to the need for calendering

Engineering Contradiction:

Improvesheet bulkVSAvoidloss of softness

Core Design Contradiction:

Volume of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The fabric elements are pre-configured with specific heights (0.4-0.7 mm) before the tissue web is formed, so that when the web is deposited and dewatered, the elements automatically provide the desired three-dimensional topography and z-directional properties without requiring subsequent calendering to achieve softness

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A structured papermaking fabric with controlled element heights serves as an intermediary between the fiber slurry and the final tissue product, transferring mechanical properties and topography to the web during formation and dewatering, thereby eliminating the need for harmful post-processing calendering

Inventive Principle:

Principle #24Intermediary (Mediator)

2Shape

If calendering is applied to improve smoothness and softness, then surface quality is improved, but strength deteriorates

Engineering Contradiction:

Improvesurface smoothnessVSAvoidtensile strength

Core Design Contradiction:

ShapeVSStrength

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Inventive Principle:

Principle #24Intermediary (Mediator)

3Shape

If high calender loads are applied to achieve smoothness, then surface quality is improved, but bulk deteriorates

Engineering Contradiction:

Improvesurface smoothnessVSAvoidsheet bulk

Core Design Contradiction:

ShapeVSVolume of stationary object

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Inventive Principle:

Principle #24Intermediary (Mediator)

4Productivity

If traditional papermaking fabrics are used for dewatering, then dewatering efficiency is achieved, but z-directional properties deteriorate

Engineering Contradiction:

Improvedewatering efficiencyVSAvoidz-directional properties

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The papermaking fabric is designed with localized three-dimensional elements of specific heights (0.4-0.7 mm) distributed across the fabric surface, creating local variations in web structure that provide enhanced z-directional properties, compression energy, and three-dimensional topography while maintaining overall dewatering efficiency

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11001032B2Single-ply resilient tissue products

Publication Date: 2021.05.11 KIMBERLY CLARK WORLDWIDE INC

AI summary

The present invention provides tissue webs and products having improved z-directional properties. The improved z-directional properties may be achieved by providing the structure with a unique three-dimensional surface topography, which increases the structure's Exponential Compression Modulus (K) and Caliper Under Load (C0). By improving both K and C0, the present inventors have also been able to provide tissue structures with relatively high Compression Energy (E), which enables the structures to be calendered at high loads without significant loss of sheet bulk or degradation of strength.