Absorbent Core C-Wrap Seals and Channel Bonding
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Solution Overview
Problem
Current absorbent articles with airfelt-free cores face challenges in immobilizing superabsorbent polymers (SAP) effectively, particularly in reducing the usage of adhesive materials while maintaining key properties such as SAP immobilization and fluid acquisition.
Innovation Solution
A substantially planar absorbent core design featuring a core wrap with a first and second substrate, where the absorbent material deposition area includes areas free of SAP, and an auxiliary glue is applied to bond the substrates in these areas, forming channels as the SAP swells, with C-wrap seals to reduce SAP movement and adhesive usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a patterned layer of SAP is immobilized by depositing a layer of fibrous thermoplastic adhesive material over the SAP, then SAP immobilization is improved, but adhesive material usage increases
Solution Approach 1:
The patent applies adhesive material only in specific locations where SAP particles are likely to migrate (edges and high-stress areas) rather than covering the entire SAP layer. This localized bonding approach maintains effective immobilization while significantly reducing the total quantity of adhesive material required.
Solution Approach 2:
The adhesive bonding is divided into discrete segments or zones rather than a continuous layer. The core wrap is bonded to the SAP layer at specific segmented locations, creating isolated bonding points that prevent SAP migration without requiring extensive adhesive coverage.
2Reliability
If the core wrap is bonded through channels to form permanent channel bonds, then channel integrity is improved, but fluid acquisition and transportation are restricted
Solution Approach 1:
The core wrap is bonded through the channels only partially, not completely sealing them. The bonding is applied at specific locations within the channels rather than along their entire length, maintaining structural integrity where needed while leaving portions of the channels open for fluid flow.
Solution Approach 2:
Different regions of the channels have different bonding characteristics. Some areas of the channels are bonded to provide structural support, while other areas remain unbonded to allow fluid acquisition and transportation. This creates localized zones with different functional properties within the same channel structure.
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 proposed design effectively immobilizes SAP, reduces adhesive material usage, and enhances fluid acquisition and distribution, maintaining performance in both dry and wet states with minimal SAP loss.
Implementation Method 1
An auxiliary glue is applied directly to the inner surface of the first substrate on an auxiliary glue application area. The auxiliary glue at least partially bonds the inner surface of the first substrate to the inner surface of the second substrate
Implementation Method 2
As the absorbent structure absorbs liquid and swells, the absorbent structure takes a three-dimensional shape with the channels becoming visible
Implementation Method 3
The absorbent material comprises at least 80% and up to 100% by weight of superabsorbent polymer... as the absorbent material swells
Implementation Method 4
The C-wrap seals of the invention can cooperate with the core wrap bonds provided within the absorbent material deposition area to reduce the freedom of movement of the SAP particles
Data Source
AI summary
Substantially planar absorbent core comprising at least 80% and up to 100% by weight of superabsorbent polymer as absorbent material on an absorbent material deposition area and a core wrap. The absorbent material deposition area comprises at least one absorbent material-free channel-forming areas through which the top and bottom substrates of the core wrap are bonded together. An auxiliary glue is applied directly at least to the inner surface of the first substrate on an auxiliary glue application area. The auxiliary glue application area is smaller than the absorbent material deposition area and the core comprises at least one C-wrap seal along at least one edge, in particular along the two longitudinally extending edges of the core.