Mechanically Deformed Absorbent Fibrous Layer
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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 sufficient 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 partially stratified and subjected to mechanical deformation processes using counter-rotating rolls with different surface speeds to reduce density and increase flexibility, allowing for the creation of zones with varying densities without the use of binder materials or additional processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If airfelt is used as absorbent core material, then the material can be processed through conventional airlaid processes, but the material exhibits low integrity, bunching and roping when wet, and insufficient capillary work potential
Solution Approach 1:
The patent changes the physical parameters of the absorbent core material by transitioning from low-density airfelt to high-density wetlaid pulp structures. This involves modifying fiber arrangement, density, and bonding characteristics to achieve improved integrity and capillary work potential while maintaining manufacturability through conventional papermaking processes
Solution Approach 2:
The patent employs composite structures combining different fiber types and densities within the absorbent core. By integrating high-density wetlaid pulp with appropriate fiber compositions and structural configurations, the material achieves both mechanical integrity and enhanced absorbent performance
2Reliability
If airfelt with low density is used, then the material can be easily processed, but it cannot provide sufficient capillary work potential
Solution Approach 1:
The patent systematically adjusts density as a key parameter, transitioning from low-density airfelt (typically 0.03-0.08 g/cc) to high-density wetlaid pulp structures (0.1-0.3 g/cc or higher). This parameter change enables sufficient capillary work potential while maintaining processability through established papermaking techniques
3Reliability
If uniform density throughout thickness is maintained, then the material structure is simple, but zones or layers with higher densities cannot be formed
Solution Approach 1:
The patent implements local quality variations within the absorbent core by creating zones and layers with different densities. The wetlaid pulp structure allows for strategic placement of high-density regions to enhance capillary action and absorbent performance in specific areas, while maintaining overall structural coherence
Solution Approach 2:
The patent divides the absorbent core into functional zones and layers with varying density characteristics. This segmentation enables different regions to perform specialized functions, with higher density zones providing enhanced capillary work potential where needed
4Reliability
If more expensive processes and materials are used to create zones with higher densities, then absorbent performance improves, but production costs and supply chain complexity increase
Solution Approach 1:
The patent utilizes conventional, cost-effective wetlaid pulp materials and standard papermaking processes to achieve high-density absorbent core structures. By relying on readily available materials and established manufacturing techniques rather than specialized expensive processes, the patent reduces production costs and supply chain complexity while maintaining superior absorbent performance
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 enhances liquid acquisition, flexibility, and tensile strength of absorbent members while reducing production costs by eliminating the need for expensive materials and complex supply chains, resulting in improved absorbent performance and manufacturing efficiency.
Implementation Method 1
subjected to mechanical deformation processes using counter-rotating rolls with different surface speeds
Implementation Method 2
cannot provide as much capillary work potential as a higher density material
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.