Absorbent Body Recessed Cover Sheet Gel Blocking Prevention
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Solution Overview
Problem
Existing absorbent articles with high content ratios of highly water-absorbent polymers are prone to gel blocking, reduced absorption capacity, and discomfort due to polymer movement during transport and use, leading to inhibited urine permeation and uneven swelling.
Innovation Solution
An absorbent body with a water-absorbent fiber stack of pulp fibers and highly water-absorbent polymers, covered by a sheet with protruding and recessed portions, where the fiber stack is stacked in the recessed areas to ensure liquid permeability and prevent polymer movement, enhancing absorption speed and capacity while preventing gel blocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the content ratio of highly water-absorbent polymers is increased to improve water absorption capacity, then the water absorption capacity is improved, but gel blocking occurs which inhibits urine permeation and reduces absorption speed
Solution Approach 1:
The absorbent body is divided into multiple layers with different functions: a first layer with high polymer content for absorption, and a second layer with lower polymer content and more pulp fibers for diffusion. This segmentation allows each layer to optimize its function without compromising the other, preventing gel blocking while maintaining high absorption capacity.
Solution Approach 2:
Different regions of the absorbent body have different compositions tailored to their specific functions. The surface region has lower polymer content to prevent gel blocking and promote diffusion, while the inner region has higher polymer content for maximum absorption. This local quality differentiation resolves the contradiction between absorption capacity and diffusion property.
2Quantity of substance
If the content ratio of highly water-absorbent polymers is increased to improve water absorption capacity, then the water absorption capacity is improved, but the polymers move during transport and accumulate in folded parts reducing absorption capacity and creating uneven swelling
Solution Approach 1:
The pulp fiber network is formed in advance to create a three-dimensional scaffold structure before the polymers are added. This preliminary action of creating the fiber network prevents polymer movement during subsequent handling and transport, while still allowing high polymer content for absorption capacity.
Solution Approach 2:
Pulp fibers serve as an intermediary material that binds and immobilizes the highly water-absorbent polymers. The fibers act as a matrix that holds the polymers in place during transport while still allowing them to function for absorption, preventing accumulation in folded parts and maintaining uniform distribution.
3Productivity
If a thin absorbent body with low basis weight of pulp is produced to improve yield and reduce cost, then the productivity and cost efficiency are improved, but the liquid diffusion property deteriorates causing gel blocking
Solution Approach 1:
The absorbent body uses local quality differentiation where the surface layer has optimized polymer-to-pulp ratio for diffusion, while the inner layer has higher polymer content for absorption. This allows the overall structure to be thin and lightweight while maintaining sufficient diffusion property in critical regions.
Solution Approach 2:
The invention uses a composite material structure combining pulp fibers and highly water-absorbent polymers in specific ratios and arrangements. The composite structure provides both the mechanical integrity needed for thin design and the diffusion pathways necessary to prevent gel blocking, achieving both productivity and reliability.
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 solution effectively prevents gel blocking, improves fluid absorption speed and capacity, maintains uniform polymer distribution, and maintains a comfortable feel by ensuring liquid permeability and preventing surface spillage and reversion.
Implementation Method 1
a water-absorbent fiber stack (8) including pulp fibers and a highly water-absorbent polymer
Implementation Method 2
highly water-absorbent polymer... swollen by water absorption
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
[Problem] To make gel blocking less likely to occur, to enable a liquid absorption speed and absorption capability to be improved, and to enable reversion to be prevented, without impairing the feeling when worn. [Solution] An absorbent body (4) is provided with a water-absorbent fiber stack (8) comprising pulp fibers and a highly water-absorbent polymer, and a cover sheet (9) covering at least a skin-facing surface of the water-absorbent fiber stack (8). Multiple protruding portions (10) which protrude outward, and recessed portions (11) that are recessed and are adjacent to the protruding portions (10) are formed on the non-skin facing surface of the cover sheet (9), and the water-absorbent fiber stacks (8) are stacked in the recessed portions (11). The water-absorbent fiber stacks (8) are provided with a thickness equivalent to or less than the height of the adjacent protruding portions (10).