Stretchable Laminate Sheet Welding Pattern Design
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Solution Overview
Problem
Stretchable laminate sheets face challenges in achieving both good air-permeability and stretchability due to the inherent non-air-permeable nature of stretchable films, which can lead to either reduced air-permeability or lower stretchability depending on film strength, and existing welding patterns do not effectively manage tension to prevent hole formation.
Innovation Solution
A stretchable laminate sheet with a thermoplastic stretchable film laminated on a non-woven fabric, featuring specific elongate welding portions arranged in a matrix pattern to distribute tension and prevent hole formation, ensuring intended air-permeability and stretchability by varying the orientation and arrangement of first and second welding portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the strength of the stretchable film is high, then the film integrity is maintained under tension, but air-permeability deteriorates due to hole formation prevention
Solution Approach 1:
The welding portions are designed with specific elongate shapes (first welding portions longer in vertical direction, second welding portions longer in girth direction) and strategically arranged in different regions (edge portions vs middle portion) to create localized variations in tension distribution. This local differentiation allows the film to maintain integrity where needed while permitting controlled hole formation for air-permeability in other areas.
2Object-generated harmful factors
If the film strength is low, then air-permeability is improved through hole formation, but stretchability is reduced due to excessive hole formation around welding portions
Solution Approach 1:
The invention changes the geometric parameters of the welding portions (elongate shape with specific length-to-width ratios, different orientations in different regions) to control the stress distribution pattern. This parameter optimization allows the film to achieve the right balance where sufficient holes form for air-permeability but the holes are controlled in size and distribution to maintain stretchability.
3Reliability
If circular or oblong welding portions are arranged in a predetermined pattern, then the non-woven fabric and stretchable film are effectively laminated, but tension distribution is uneven leading to hole formation or reduced air-permeability
Solution Approach 1:
The invention replaces symmetric circular or uniform oblong welding portions with asymmetric elongate welding portions that have different length-to-width ratios and orientations depending on their location. First welding portions in vertical direction and second welding portions in girth direction create intentional asymmetric tension distribution that matches the stress patterns in different regions of the laminate sheet.
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 balances air-permeability and stretchability by strategically arranging welding portions to manage tension, preventing large hole formation and maintaining the integrity of the laminate sheet under various directional stresses.
Implementation Method 1
the non-woven fabric and the stretchable film are welded together at a plurality of first welding portions and a plurality of second welding portions
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
A stretchable laminate sheet including a thermoplastic stretchable film laminated on a non-woven fabric containing thermoplastic fiber therein, wherein: the non-woven fabric and the stretchable film are welded together at a plurality of first and second welding portions; the first welding portions are longer in a first direction and are shorter in a second direction perpendicular to the first direction; and the second welding portions are longer in a third direction crossing the first direction and are shorter in a fourth direction perpendicular to the third direction.