Absorbent Core Adhesive Layer for SAP Immobilization
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Solution Overview
Problem
Current absorbent cores for personal hygiene products, such as diapers, face challenges in maintaining structural integrity and fluid handling performance, especially when saturated, and struggle with precise distribution of superabsorbent polymer particles, leading to increased material usage and costs.
Innovation Solution
The development of an absorbent core structure comprising a first absorbent layer with superabsorbent polymer particles coated by a fibrous layer of thermoplastic adhesive material and a second layer with a mixture of superabsorbent particles and cellulosic fibers, allowing for improved immobilization and distribution of absorbent materials, enhancing dry and wet integrity and fluid handling capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If SAP concentration is increased to improve absorbency capacity, then fluid acquisition capacity is improved, but SAP separates from cellulose fibers and structural integrity deteriorates
Solution Approach 1:
A fibrous adhesive layer is introduced as an intermediary between the SAP particles and the cellulose fibers. This adhesive layer binds the SAP particles to the cellulose matrix, preventing separation even at high SAP concentrations. The adhesive acts as a mediator that maintains structural integrity while allowing high absorbency capacity.
Solution Approach 2:
The absorbent core is designed as a composite material system comprising cellulose fibers, superabsorbent polymer particles, and a fibrous adhesive layer. This composite structure combines the high absorbency of SAP with the structural integrity of cellulose, held together by the adhesive, creating a material that achieves both high capacity and maintained strength.
2Productivity
If production speed is increased to improve productivity, then manufacturing efficiency is improved, but SAP distribution precision deteriorates
Solution Approach 1:
The fibrous adhesive layer is applied in advance to the cellulose substrate before SAP particles are deposited. This preliminary action creates a pre-prepared surface that facilitates uniform SAP distribution during high-speed production, as the adhesive is already in position to capture and hold SAP particles as they are deposited.
Solution Approach 2:
The fibrous adhesive layer serves as an intermediary medium that enables precise SAP distribution at high production speeds. The adhesive fibers provide numerous binding sites that uniformly capture SAP particles during rapid deposition, ensuring consistent distribution patterns even when production speed increases.
3Quantity of substance
If more SAP is added to compensate for poor distribution, then absorbency capacity is improved, but material cost increases
Solution Approach 1:
The fibrous adhesive layer acts as a mediator that ensures efficient utilization of SAP particles by preventing their separation and loss. This improves the effectiveness of each SAP particle, allowing reduced SAP quantities to achieve the same absorbency capacity, thereby reducing material costs.
Solution Approach 2:
The introduction of the adhesive layer changes the system parameters by improving SAP retention and distribution uniformity. This parameter change allows optimization of SAP quantity to the minimum effective amount needed, reducing material waste and cost while maintaining required absorbency capacity.
4Volume of moving object
If core thickness is reduced to improve fit and reduce material usage, then cost and environmental impact are improved, but structural integrity deteriorates
Solution Approach 1:
The thin core is designed as a composite structure where the fibrous adhesive layer creates a cohesive network binding cellulose fibers and SAP particles together. This composite architecture provides enhanced structural integrity relative to the thin profile, allowing reduced thickness without sacrificing strength.
Solution Approach 2:
The fibrous adhesive layer serves as a binding intermediary that maintains structural integrity in thin cores. By creating strong bonds between constituent materials, the adhesive enables the core to maintain its shape and strength even when thickness is minimized for better fit and reduced material usage.
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
This design improves the structural integrity and fluid handling performance of absorbent cores, reducing the need for high permeable superabsorbent polymers, lowering material costs, and providing flexibility in formulation to adapt to price changes, while maintaining effective absorbency and dryness.
Implementation Method 1
a fibrous layer of thermoplastic adhesive material covering the first superabsorbent polymer particles
Implementation Method 2
The absorbent core's function is to absorb and retain the exudates for a prolonged amount of time
Implementation Method 3
Absorbent cores can expand to several times their initial volumes when saturated
Data Source
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AI summary
An absorbent article (20) comprising a wearer-facing topsheet (24), a backsheet (26) and an absorbent core (28) disposed between the topsheet and the backsheet, characterized in that the absorbent core comprises: a first absorbent layer (1) comprising a first substrate (2), a layer (3) of first superabsorbent polymer particles deposited on the first substrate, and a fibrous layer (4) of thermoplastic adhesive material covering the layer of first superabsorbent polymer particles; a second absorbent layer (5), the second absorbent layer comprising a second substrate (6) and a mixed layer (7) deposited on the second substrate, the mixed layer comprising a mixture of second superabsorbent particles and cellulosic fibers, the first absorbent layer and the second absorbent layer being combined together such that at least a portion of the fibrous layer (4) of thermoplastic adhesive material of the first absorbent layer contacts at least a portion of the mixed layer (7) of the second absorbent layer (5), and wherein the first absorbent layer (1) is placed closer to the topsheet than the second layer (5).