Bridged Absorbent Structure Basis Weight Control
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Solution Overview
Problem
Existing methods for forming laid fibrous webs struggle to create reliable and efficient gradations in basis weight, often compromising structural integrity and failing to achieve desired gradations in low basis weight areas.
Innovation Solution
The use of a forming apparatus with masking plates that have partitions to control airflow and fibrous material distribution on a foraminous forming surface, allowing for the formation of bridged areas with lower basis weights relative to continuous areas of higher basis weights, thereby achieving gradations in basis weight through the fibrous web.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If vacuum suction is used to draw the air-entrained fiber stream onto the forming surface, then high-speed commercial operations are enabled, but it is difficult to direct desired amounts of fiber material into pocket regions for high basis weight formation
Solution Approach 1:
The forming surface is divided into multiple zones with different vacuum suction characteristics. Pocket regions are created with modified vacuum exposure to control fiber deposition, allowing high-speed operation while achieving precise basis weight gradations in different areas of the formed web.
2Manufacturing precision
If blocking components are positioned underneath the forming surface to partially block airflow, then fiber deposition is inhibited above blocked sections, but the method does not provide gradations in low basis weight areas
Solution Approach 1:
Different regions of the forming surface are given different vacuum suction characteristics through selectively positioned blocking components. This creates local variations in fiber deposition, enabling precise control of basis weight in both high and low basis weight areas simultaneously.
3Manufacturing precision
If voids are formed in the fibrous web through the thickness, then basis weight gradations are produced, but the voids affect structural integrity and do not allow additional gradations
Solution Approach 1:
Instead of creating voids through the entire thickness of the web, the invention creates controlled variations in fiber density within the plane of the web while maintaining structural continuity through the thickness. This achieves basis weight gradations without compromising structural integrity.
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 approach enables the production of fibrous webs with controlled basis weight gradations, enhancing the structural integrity and performance of absorbent structures by varying the amount of fibrous material and superabsorbent distribution, leading to improved absorbency and comfort in absorbent articles.
Implementation Method 1
employ a suitable pneumatic flow mechanism, such as vacuum suction apparatus, to define a differential pressure zone on the forming surface and impose a pressure differential thereon
Implementation Method 2
The use of vacuum suction to draw the air-entrained fiber stream onto the forming surface
Implementation Method 3
The fibers and superabsorbent particles are then entrained in an air stream and directed to a suitable foraminous forming surface upon which the fibers and superabsorbent particles are deposited
Implementation Method 4
blocking components have been positioned underneath the forming surfaces to partially block the airflow through the forming surfaces and, thus, inhibit airlaid fibers from being deposited above the blocked off sections
Data Source
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AI summary
An absorbent structure includes a first area of fibrous absorbent material and a second area of fibrous absorbent material. The first area has a greater basis weight than the second area. The second area includes a plurality of segments separated by vertical interfaces. Each of the vertical interfaces has a width less than 1 cm. Bridging of fibrous absorbent material extends across the vertical interfaces.