Absorbent product with improved capillary pressure and saturation capacity
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Solution Overview
Problem
Conventional absorbent articles, such as disposable wipers, face a trade-off between high capillary pressure for quick fluid uptake and high absorbent capacity, with layered wipers failing to improve performance due to low capillary pressure at interfaces.
Innovation Solution
A multi-layer fibrous web with distinct layers, including a high pick-up speed layer made of pulp fibers and a high absorbent capacity layer made of elastomeric polymer fibers, formed through a foaming process to create a crossover zone with intermediate capillary pressure, enhancing fluid transfer and absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional absorbent products are used, then they provide basic absorption, but they exhibit high capillary pressure that prevents wetting by low surface tension fluids
Solution Approach 1:
The absorbent core is divided into multiple layers with different pore sizes - a first layer with larger pores and a second layer with smaller pores. This segmentation allows the larger pores to accept low surface tension fluids first (overcoming the capillary pressure barrier), then transfer them to the smaller pores for controlled distribution, thereby resolving the contradiction between high capillary pressure and wetting capability.
Solution Approach 2:
Different regions of the absorbent core are assigned different properties - the first layer has larger pores optimized for initial fluid acceptance and low surface tension fluid interaction, while the second layer has smaller pores optimized for fluid distribution. This local quality differentiation enables the core to simultaneously overcome capillary pressure barriers and achieve reliable wetting.
2Quantity of substance
If absorbent products with high saturation capacity are used, then they can absorb more fluid, but they take longer to reach saturation
Solution Approach 1:
The segmented layer structure with different pore sizes enables simultaneous optimization of absorption speed and saturation capacity. The larger pores in the first layer quickly accept fluid (high productivity), while the smaller pores in the second layer provide extensive surface area for high saturation capacity. The transfer mechanism between layers ensures both speed and capacity are achieved.
Solution Approach 2:
The invention introduces a dimensional aspect by creating a vertical gradient in pore size through multiple layers. This dimensional change allows the system to optimize different functions at different levels - rapid acceptance at the top layer and extensive distribution at lower layers - thereby achieving both high absorption speed and high saturation capacity.
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 multi-layer fibrous web achieves improved absorbent capacity and fluid pick-up speed, maintaining performance even at high saturation levels, exceeding 5.5 g/g fluid absorption and 1.6 (g/g)*sec^0.5 absorbent rate.
Implementation Method 1
it has been recognized that absorbent products comprising a melt-blown web exhibit high capillary pressure which prevents wetting by low surface tension fluids
Implementation Method 2
coating the melt-blown web with a hydrophilic polymer to increase saturation capacity
Data Source
Figure 1
Figure 2A~2B
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AI summary
A process for forming multi-layer fibrous web with good absorbent capacity and absorbent rate is disclosed. The multi-layer fibrous web can be used as absorbent articles, including wiping products, such as industrial wipers, food service wipers, and the like. The multi-layer fibrous web includes a first layer and a second layer, as well as a crossover zone, that has a capillary pressure between the capillary pressure of the first layer and the capillary pressure of the second layer.