Stretchable Sheet Manufacturing via Controlled Gear Drawing
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Solution Overview
Problem
The 'gear drawing' method for manufacturing stretchable sheets can cause significant damage to nonwoven fabrics due to varying distortion speeds during the process, leading to potential fabric rupture.
Innovation Solution
A method involving passing a nonwoven fabric through a gap between rotating gear rolls with controlled circumferential velocities between 50 to 300 m/min and setting the maximum distortion per unit time within 5 to 100 sec−1 to minimize fabric damage, using gear rolls with diameters between 300 to 600 mm, and incorporating thermoplastic elastomer and thermoplastic polyolefin fibers for enhanced stretchability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the nonwoven fabric is drawn by engagement of the teeth of gear rolls, then stretchability is developed in the nonwoven fabric, but the nonwoven fabric may be seriously damaged or ruptured during the drawing
Solution Approach 1:
The patent applies parameter changes by precisely controlling the circumferential velocity of gear rolls within 50-300 m/min and the maximum distortion speed within 5-100 sec⁻¹. This optimization of process parameters enables the drawing process to develop stretchability in the nonwoven fabric while preventing fiber rupture and fabric damage, thus resolving the contradiction between improving stretchability and avoiding damage.
2Productivity
If the circumferential velocity of gear rolls is increased to improve productivity, then the drawing process becomes faster, but the distortion speed increases causing more damage to the nonwoven fabric
Solution Approach 1:
The patent resolves this contradiction by establishing an optimized parameter range where circumferential velocity is controlled at 50-300 m/min and maximum distortion speed at 5-100 sec⁻¹. This parameter optimization allows the system to achieve high productivity through increased drawing speed while simultaneously preventing fabric damage by keeping distortion speed within safe limits.
Solution Approach 2:
The patent applies dynamics by making the gear roll system adjustable and adaptable. The circumferential velocity can be dynamically controlled within the optimal range of 50-300 m/min, allowing the process to adapt to different fabric types and production requirements while maintaining the balance between productivity and fabric integrity.
Data Source
AI summary
A method of producing a stretchable sheet that involves: passing a nonwoven fabric including a plurality of types of fibers through a gap between a pair of gear rolls and that rotate while a plurality of teeth and formed on an outer circumferential surface and of each of the pair of gear rolls and engage with one another; and drawing the nonwoven fabric in a circumferential direction of the gear rolls and by the teeth. A circumferential velocity S of the gear rolls and is within a range of 50 to 300 m/min. A maximum value of distortion per unit time applied to the nonwoven fabric in the gap between the pair of gear rolls and is within a range of 5 to 100 sec−1.