Multi-layered non-woven structure for use as a component of disposable absorbent articles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional disposable absorbent articles face challenges in maintaining liquid holding capacity and distribution without increasing complexity or cost, particularly due to gel-blocking effects caused by superabsorbent polymer (SAP) particles, which can lead to liquid reflux and re-wetting issues when pressure is applied.
Innovation Solution
A multilayer nonwoven acquisition and distribution sheet material comprising three layers: a first layer for acquiring and transferring fluids, a second layer with smaller void volumes to prevent fluid reflux, and a third layer with SAP particles for absorption, creating a pressure gradient that prevents fluid return and enhances liquid intake and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If SAP particles are used to increase absorbent capacity, then liquid holding capacity is improved, but gel-blocking effect occurs causing liquid reflux and re-wetting
Solution Approach 1:
The absorbent core is divided into multiple layers with different functions: a first layer with larger voids for rapid liquid acquisition and transmission, a second layer with smaller voids for distribution and preventing reflux, and a third layer containing SAP particles for absorption. This segmentation allows each layer to perform its specific function optimally while working together to prevent gel-blocking and liquid reflux.
Solution Approach 2:
Different regions of the absorbent core are assigned different properties: the first layer has larger void volumes optimized for rapid liquid transmission, the second layer has smaller void volumes optimized for preventing reflux and distributing liquid, and the third layer contains SAP particles for absorption. This local differentiation of properties allows the system to simultaneously achieve rapid acquisition, prevent reflux, and maintain high absorbent capacity.
2Volume of moving object
If fluff amount is reduced to make thinner articles, then productivity and thinness are improved, but liquid holding capacity and pressure resistance deteriorate
Solution Approach 1:
The invention merges the functions of fluff (liquid distribution and pressure resistance) and SAP particles (liquid absorption) into an integrated multilayer absorbent core. The first and second layers provide fluff-like liquid holding and distribution capabilities, while the third layer provides SAP-based absorption, eliminating the need for separate fluff layers and reducing overall article thickness while maintaining or improving liquid holding capacity.
Solution Approach 2:
The absorbent core uses a composite structure combining different fibrous materials with distinct void volume characteristics. The first layer uses materials with larger voids for rapid transmission, the second layer uses materials with smaller voids for reflux prevention, and the third layer incorporates SAP particles. This composite approach allows thinning of the overall structure while maintaining superior liquid holding and pressure resistance properties.
3Volume of moving object
If SAP to fluff ratio is increased for fluff-less cores, then thinness is improved, but pressure resistance and liquid distribution deteriorate
Solution Approach 1:
The absorbent core is segmented into three functional layers: a first layer with larger voids for rapid liquid acquisition and transmission under pressure, a second layer with smaller voids for distributing liquid and preventing reflux, and a third layer with SAP particles for absorption. This segmentation ensures that even with high SAP content and reduced fluff, liquid distribution under pressure remains effective through the coordinated action of the first two layers.
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 multilayer structure effectively reduces fluid reflux and re-wetting, improving the absorbent capacity and retention of disposable absorbent articles while maintaining thinness and reducing the need for additional fluff, thereby enhancing the overall performance without increasing complexity or cost.
Implementation Method 1
Acquisition layers are generally composed of coarse fibers that quickly transmit the liquid by capillarity to the dispersion layer.
Implementation Method 2
the second layer with smaller void volumes to prevent fluid reflux, and a third layer with SAP particles for absorption, creating a pressure gradient that prevents fluid return
Implementation Method 3
the third layer comprising superabsorbent polymer (SAP) particles, for receiving the body fluids from the second layer
Implementation Method 4
wet SAP particles are subject to swelling and can therefore form a gel with the adjacent swollen SAP particles. Said gel formation, often referred to as the gel-blocking effect, can block the liquid transmission towards the inner portion of the absorbent core. To prevent gel blocking and to improve the fluid absorbent capacity of the absorbent core, individual SAP particles have to be sufficiently distant from one another, i.e. leaving voids between them.
Data Source
AI summary
The present invention relates to multi-layered non-woven structures being useful as components of disposable absorbent articles and garments comprising super absorbent particles and thereby acts as a core. The invention thereby ensures that the body fluids can penetrate from a first layer, which acts as an acquisition layer, up to a third layer comprising SAP particles, the second non-woven layer serving to decrease the fluid volume per surface unit, as a conventional dispersion layer. However the second layer of the invention additionally acts like a non-return valve, preventing, or at least strongly limiting, any fluid transfer from the third layer to the first layer. Channels free of SAP can additionally be design to improve the inlet and rewet properties of the multilayer acquisition and distribution sheet non-woven material.