Non-woven Web Forming Fabric with Interwoven Yarn Pattern
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Solution Overview
Problem
High-speed spun-bond manufacturing lines face challenges with fabrics that compromise between web hold-down and fiber bleed, with high-speed fibers exhibiting bounce and air leakage due to high velocity and small diameter, necessitating a fabric with high permeability and low bleed to prevent uncontrollable fiber splashing and air disturbances.
Innovation Solution
A fabric with machine direction (MD) and cross-machine direction (CMD) yarns interwoven in specific patterns, including pairs following the same weaving sequence, provides improved web hold-down and reduced air leakage, utilizing round monofilaments and static dissipative yarns to guide air flow and facilitate dirt removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a fabric provides good hold down of the web, then web hold-down is improved, but fiber penetration and bleed through into the fabric or belt increases
Solution Approach 1:
The fabric is segmented into distinct functional zones with different yarn types and weave patterns. Machine direction yarns provide structural integrity and hold-down, while cross-machine direction yarns with varying openness control fiber penetration. This segmentation allows different regions of the fabric to perform specialized functions simultaneously.
Solution Approach 2:
Different areas of the fabric have locally optimized properties. The weave pattern varies across the fabric width and length, with some regions having tighter weaves for hold-down and others having more open structures to prevent fiber penetration. This local quality variation resolves the contradiction between hold-down and bleed prevention.
2Productivity
If high velocity small diameter fibers are used for high-speed spinning, then productivity is improved, but bounce at impact and bleed through fabric increases
Solution Approach 1:
The fabric acts as an intermediary structure between the high-velocity fibers and the final web product. The specifically designed weave pattern with alternating tight and open regions mediates the impact of high-velocity fibers, capturing them effectively while preventing excessive bounce and bleed through the fabric.
Solution Approach 2:
The fabric utilizes controlled porosity through its weave structure. The open regions in the weave pattern allow high-velocity fibers to pass through without excessive impact, reducing bounce, while the overall fabric structure maintains sufficient density to prevent uncontrolled bleed through. This porous design enables high-speed spinning without the harmful effects of fiber bounce.
3Quantity of substance
If fabric open area is increased to allow air flow, then permeability is improved, but fiber bleed through increases
Solution Approach 1:
The fabric design addresses the permeability-bleed contradiction by operating in multiple dimensions. The weave pattern creates three-dimensional fiber entanglement within the fabric structure, where fibers are captured in the interstices of the weave. This dimensional approach allows high air permeability through the open weave while the multi-layer fiber entanglement prevents fiber bleed through.
Data Source
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AI summary
A method of manufacturing a non-woven web includes the step of collecting stretched filaments that form the non-woven web on a fabric in an apparatus for the formation of non-woven webs. The fabric comprises machine direction (MD) yarns and cross-machine direction (CMD) yarns, wherein the MD and CMD yarns are interwoven in a repeating pattern in which at least some of the CMD yarns are interwoven with the MD yarns in pairs that follow the same weaving sequence. Such a fabric can provide potential advantages such as reduced air leakage, reduced air disturbances, and improved web hold-down effect.