High-Loft Absorbent Core Structure for Fast SAP Uptake
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Solution Overview
Problem
Existing absorbent cores in personal hygiene products, such as baby diapers, face challenges in achieving fast absorption speed, reduced rewet, and improved wearer comfort while maintaining low manufacturing costs, particularly in airfelt-free designs.
Innovation Solution
An absorbent core comprising a high loft central layer with superabsorbent polymer particles distributed within, having a density below 0.20 g/cm³ and a time to reach an uptake of 20 g/g of less than 220 seconds, along with a top and bottom layer, enhances absorption speed and reduces rewet by using a heterogenous SAP distribution and a C-wrap construction to immobilize particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If superabsorbent polymer particles are distributed within a high loft central layer, then absorption speed is enhanced, but manufacturing complexity increases
Solution Approach 1:
The absorbent core is segmented into distinct functional layers: a high loft central layer for rapid absorption, a SAP distribution layer for immobilizing superabsorbent particles, and a low loft layer for containment. This segmentation allows each layer to be optimized independently, achieving fast absorption speed while managing manufacturing complexity through modular construction
Solution Approach 2:
The patent introduces a vertical layering dimension to distribute SAP particles throughout the core structure rather than mixing them uniformly. By placing SAP in a dedicated distribution layer adjacent to the high loft central layer, the design achieves rapid absorption kinetics while simplifying the manufacturing process through sequential layer deposition
2Stability of the object's composition
If SAP particles are immobilized with adhesive, then particle containment is improved, but manufacturing cost increases
Solution Approach 1:
The patent extracts the SAP immobilization function from the bulk adhesive mixture and concentrates it in a separate SAP distribution layer. This layer acts as a dedicated containment zone that physically traps SAP particles through the layered structure itself, reducing or eliminating the need for adhesive binders and thereby lowering manufacturing costs while maintaining particle containment
Solution Approach 2:
The SAP distribution layer serves as an intermediary structure between the high loft central layer and the low loft containment layer. This intermediate layer physically confines SAP particles through its position in the layered architecture, providing particle containment without requiring chemical adhesives, thus reducing manufacturing complexity and cost
3Quantity of substance
If high SAP content is used, then absorption capacity is improved, but liquid distribution length increases causing rewet
Solution Approach 1:
The patent applies local quality by concentrating high SAP content specifically in the SAP distribution layer adjacent to the high loft central layer, rather than uniformly throughout the entire core. This localized SAP placement ensures high absorption capacity at the fluid entry point while the low loft containment layers limit lateral liquid distribution, preventing rewet at the front and back of the core
Solution Approach 2:
The layered vertical structure creates distinct zones for different functions: rapid absorption in the high loft central layer, high-capacity storage in the SAP distribution layer, and lateral containment by the low loft layer. This dimensional separation allows high SAP content to be used effectively without increasing liquid distribution length, as the low loft layer acts as a barrier to lateral fluid movement
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 absorbent core achieves rapid absorption, minimizes leakage and rewet, and maintains wearer comfort by utilizing a high loft central layer with low-density nonwoven and SAP particles, ensuring efficient fluid management and improved dryness.
Implementation Method 1
The absorbent core comprises superabsorbent polymer particles (SAP), which are at least partially distributed within the central layer... fast speed of absorption... time to reach an uptake of 20 g/g (SAP T20) of less than 220s
Implementation Method 2
superabsorbent polymer particles (SAP)... absorb and contain body exudates... absorption capacity... uptake of 20 g/g
Implementation Method 3
The central layer is a high loft layer such as a carded nonwoven... liquid distribution length... wearer comfort... minimizing rewet
Data Source
Figure 1~2a
Figure 2b~3
Figure 4~5
AI summary
An absorbent core (28) for use in an absorbent article (20) having a high loft central layer (43) between a top layer and a bottom layer and superabsorbent particles (SAP) at least partially distributed within the high loft layer. The superabsorbent polymer particles have a time to reach an uptake of 20 g/g (SAP T20) of less than 220 s, and/or the absorbent core has a time to reach an uptake of 15 g/g (Core T15) of less than 200 s, and/or the absorbent core has a permeability (core K20) of more than 6.0 x 10-8 cm2. These properties are measured according to the K(t) Test Method as described in the application.