Stretchable Sheet Structure With Linear Joining Units
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Solution Overview
Problem
Existing disposable absorbent products with stretchable sheet structures face issues of increased stiffness due to the use of hot-melt adhesive or dot-shaped elastic members, leading to discomfort and reduced surface area for ridges and grooves, and the gathers can excessively contact the skin, causing irritation.
Innovation Solution
A stretchable sheet structure is designed with linear joining units aligned in the stretching direction, intersecting with elastic members, and having varying joining widths at intersecting positions to form gathers with orderly ridges and grooves, using welding for joining sheets to maintain flexibility and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If hot-melt adhesive is applied linearly in fixed-interval strips to join elastic members, then joining strength is improved, but stiffness increases and touch quality degrades
Solution Approach 1:
The patent changes the joining method from hot-melt adhesive to ultrasonic welding, altering the physical-chemical parameters of the joining process. Ultrasonic welding uses vibration energy to melt and fuse thermoplastic materials, providing strong joints without the residual adhesive that causes stiffness and poor touch quality.
Solution Approach 2:
The patent replaces the chemical bonding mechanism of hot-melt adhesive with a mechanical-vibrational mechanism of ultrasonic welding. The ultrasonic vibration generates friction heat that melts the thermoplastic gather sheet material, creating strong mechanical bonds without requiring adhesive materials.
2Strength
If dot-shaped joining units are used to join sheets and elastic members, then joining strength is maintained, but the area of sheet surfaces available as ridges and grooves is reduced
Solution Approach 1:
The patent segments the joining function from the ridge/groove formation function. The ultrasonic welding is applied only at specific locations where elastic members need to be secured, while leaving the rest of the gather sheet surface uninterrupted to form ridges and grooves. This segmented approach maximizes the functional surface area.
Solution Approach 2:
The patent applies different properties to different parts of the gather sheet: the regions with ultrasonic welding points provide localized strength and elasticity, while the regions between welding points maintain the smooth, continuous surface quality needed for ridges and grooves that contact the wearer's skin.
3Stability of the object's composition
If ridges and grooves are formed perpendicularly to the direction of extension, then structural stability is improved, but stiffness increases causing excessive skin contact and irritation
Solution Approach 1:
The patent makes the gather sheet dynamically adaptable by using elastic materials and ultrasonic welding that preserve material flexibility. The gather sheet can dynamically adjust its shape and contact pressure in response to wearer movement and body contours, reducing rigid, irritating contact while maintaining structural integrity through the elastic recovery of the material.
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 structure provides appropriate stiffness while forming gathers with orderly ridges and grooves, reducing skin contact discomfort and enhancing wearing comfort by allowing the gathers to deform smoothly, while maintaining effective leakage prevention.
Implementation Method 1
a first elastic member positioned between the first sheet and the second sheet and extending linearly in the stretching direction, and a second elastic member positioned between the first sheet and the second sheet and extending linearly in the stretching direction... While the first elastic member and the second elastic member shrink, the first sheet or the second sheet has bulges between the plurality of linear joining units to form gathers
Implementation Method 2
the first sheet and the second sheet are joined together by a plurality of linear joining units aligned in the stretching direction... using welding for joining sheets to maintain flexibility and comfort
Data Source
AI summary
A gather sheet (32) having a stretchable sheet structure includes an inside sheet (331), an outside sheet (332), a first elastic member (3221), a second elastic member (3222), and a third elastic members (3223), the first to third elastic members being positioned between the inside sheet (331) and the outside sheet (332) and extending in a stretching direction. The inside sheet (331) and the outside sheet (332) are joined together by a plurality of linear joining units (5) aligned in the stretching direction. Joining widths of each linear joining units (5) at intersecting positions of the linear joining units and the first to third elastic members (3221 to 3223) are greater than joining widths of the linear joining units at any position between adjacent ones of the intersecting positions.