Binderless Liquid Storage Layer for Flexible Absorbent Structures
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional absorbent structures with liquid storage layers experience reduced capacity to absorb additional liquid due to adhesive effects between superabsorbent particles when moistened, leading to decreased wearing comfort and increased stiffness, which impairs flexibility and mobility.
Innovation Solution
A multilayer absorbent structure with a liquid storage layer devoid of binders, allowing superabsorbent polymers to swell freely and maintain mobility, combined with latex-based binder layers on outer surfaces for stability, and a calendering process for loose compression to achieve flexibility and high absorption capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a liquid storage layer contains binders to stabilize the structure, then structural stability is improved, but flexibility and mobility are reduced
Solution Approach 1:
The absorbent structure is divided into multiple functional layers: an outer stabilizing layer containing binders for structural stability, and an inner liquid storage layer without binders for flexibility and mobility. This segmentation allows each layer to independently perform its specific function without compromising the other.
Solution Approach 2:
Different regions of the absorbent structure have different properties: the outer layer has high structural stability with binders, while the inner liquid storage layer has high flexibility and mobility without binders. This local differentiation of properties optimizes both structural integrity and functional performance.
2Quantity of substance
If superabsorbent particles are compacted to increase density, then absorption capacity per volume is improved, but ability to return to original shape is reduced
Solution Approach 1:
The liquid storage layer is designed to be dynamically responsive to liquid absorption. When liquid is absorbed, the layer expands and changes shape; when liquid is removed, it returns to its original shape. This dynamic behavior is enabled by the absence of binders that would restrict movement.
Solution Approach 2:
The physical state and volume of the liquid storage layer change dynamically based on liquid absorption. The layer can transition between compressed and expanded states, and this reversible parameter change is maintained through the binderless design that allows free movement of superabsorbent particles.
3Strength
If binders are used in the liquid storage layer to prevent fiber abrasion, then structural integrity is improved, but adhesive effects between particles increase reducing absorption capacity
Solution Approach 1:
The binders are extracted from the liquid storage layer, leaving only the superabsorbent particles and fluff pulp. This removal eliminates the adhesive effects between particles that would reduce absorption capacity, while the outer stabilizing layer provides the necessary structural integrity.
Solution Approach 2:
The outer stabilizing layer acts as an intermediary that provides structural integrity for the entire absorbent structure without interfering with the inner liquid storage layer's absorption function. This mediator layer protects the binderless inner layer from mechanical degradation.
4Quantity of substance
If the liquid storage layer is compressed during use, then liquid absorption is enhanced, but permanent deformation occurs reducing wearing comfort
Solution Approach 1:
The liquid storage layer is designed with dynamic reversibility. Compression during liquid absorption is temporary and reversible; the layer returns to its original shape and configuration after liquid absorption, maintaining wearing comfort throughout use.
Solution Approach 2:
The liquid storage layer automatically returns to its original state after compression without external intervention. The binderless structure enables self-recovery through the natural movement and rearrangement of superabsorbent particles, eliminating the need for external restoring mechanisms.
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 structure maintains original shape and mobility, enhancing wearing comfort by allowing the liquid storage layer to return to its original state and maintaining high absorption capacity, reducing stiffness and improving rewettability.
Implementation Method 1
When an absorbent structure, which for example comprises a liquid absorption layer, a liquid storage layer, and a liquid distribution layer, is wetted by a liquid, the liquid is drawn from the liquid absorption layer into the liquid storage layer by capillary action.
Implementation Method 2
the superabsorbent polymers to swell freely and maintain mobility
Implementation Method 3
latex-based binder layers on outer surfaces for stability
Implementation Method 4
a calendering process for loose compression to achieve flexibility
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to an absorbent structure having a sequence of layers, comprising at least one first and one second outer layer and at least one liquid storage layer arranged therebetween, wherein the layers are arranged on top of each other and form a layer structure, wherein at least the liquid storage layer comprises a cellulose material, preferably cellulose fibers, and a superabsorbent polymer SAP, preferably SAP particles and/or SAP fibers, wherein the liquid storage layer comprises at least less, preferably no, binder than liquid-storing layers of the absorbent structure adjacent to the liquid storage layer. The absorbent structure has particularly high flexibility in the wet and the dry state. It can preferably be used in disposable items. The invention further relates to a method for producing the absorbent structure and to a device for producing same.