Mechanically Deformed Bulk Absorbent Core for Wet Integrity
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Solution Overview
Problem
Current absorbent core materials in disposable absorbent articles, such as airfelt, have limitations including low integrity, bunching and roping when wet, low density, and inability to provide capillary work potential, leading to increased costs and complexity in manufacturing due to the need for more expensive processes and materials.
Innovation Solution
The development of bulked absorbent members with a unitary absorbent fibrous layer comprising cellulose fibers, which are mechanically deformed using counter-rotating rolls with different surface speeds to create a stratified structure with discrete deformations and increased void volume, reducing density and stiffness while enhancing flexibility and fluid retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If airfelt is used as absorbent core material, then the material can be produced, but it has low integrity and bunches and ropes when wet
Solution Approach 1:
The patent changes the physical parameters of the absorbent core by creating a bulked, fluffed structure with controlled density distribution. The core is formed with a lower density overall but with strategic higher density zones, changing the mechanical properties to prevent bunching and roping while maintaining integrity when wet.
Solution Approach 2:
The patent uses a composite structure combining different fiber types and densities within the absorbent core. The core includes a mixture of wood pulp fibers and other fibrous materials arranged in a bulked structure with varying density zones, creating a composite material that resists deformation when wet.
2Reliability
If airfelt is used as absorbent core material, then the material can be produced, but it has low density and cannot provide sufficient capillary work potential
Solution Approach 1:
The patent applies local quality by creating zones of different densities within the absorbent core. The core has higher density regions that provide capillary work potential for liquid acquisition and lower density regions that provide bulk and storage capacity. This spatial variation in density allows the low-density core to still provide sufficient capillary action where needed.
3Reliability
If airlaid structures with zones of higher densities are used, then the absorbent performance is improved, but the process cost and supply chain complexity increase significantly
Solution Approach 1:
The patent merges the functions of core formation and density zoning into a single integrated process. Instead of separately producing airfelt and then adding binder materials and super-absorbent polymers in a complex airlaid process, the patent forms the bulked core with embedded density variations in one continuous process, eliminating intermediate steps and reducing supply chain complexity.
Solution Approach 2:
The patent uses inexpensive, readily available wood pulp fibers and simple mechanical processing to create the absorbent core, replacing expensive binder materials and complex airlaid processing with a simpler, more cost-effective wetlaid process that achieves the desired performance without requiring expensive additives or multi-step manufacturing.
4Ease of manufacture
If drylap is shipped to the absorbent article manufacturer for comminution, then the material can be processed, but shipping costs and manufacturing complexity increase
Solution Approach 1:
The patent inverts the conventional process sequence by forming the bulked absorbent core directly from wetlaid paper in a continuous process at the absorbent article manufacturer, eliminating the need to ship drylap to intermediate suppliers for comminution. The process is reversed from the traditional approach of shipping raw material for processing to processing material on-site, reducing shipping time and manufacturing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution results in absorbent members with improved liquid acquisition, flexibility, and tensile strength, while reducing production costs by eliminating the need for expensive binder materials and complex supply chains, and providing a more efficient absorbent core for disposable articles.
Implementation Method 1
passing the precursor web through a nip between counter-rotating rolls that are rotating at different surface speeds
Implementation Method 2
The unitary absorbent fibrous layer has a plurality of discrete deformations in the first and second surfaces
Data Source
AI summary
Absorbent members, especially bulked absorbent members, and methods of making the same are disclosed. The absorbent member may be in the form of a unitary absorbent fibrous layer comprising at least some cellulose fibers. The unitary absorbent fibrous layer is at least partially stratified through its thickness. The absorbent member may also have a plurality of discrete deformations, such as depressions and/or apertures in its surfaces. The method involves subjecting a precursor web to at least one cycle (or pass) through a mechanical deformation process. The mechanical deformation process utilizes a first forming member and a second forming member that form a nip therebetween through which the precursor web is passed. The first and second forming members are moving at different speeds relative to each other when they come together to form the nip.