Elastic Composite Sheet Bonding Without Edge Breakage
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Solution Overview
Problem
Existing methods for producing elastic composite sheets fail to create a surface unevenness and can cause breakage of the elastic member when bonded to a base material sheet in a stretched state.
Innovation Solution
The method involves stretching an elastic member composed of thermoplastic elastic resin, bonding it to a base material sheet using ultrasonic bonding at locations away from the edges, and sandwiching it between two base material sheets to prevent breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If ultrasonic bonding is used to bond an elastic member in a stretched state to a base material sheet, then bonding strength is improved, but the elastic member may break
Solution Approach 1:
The ultrasonic bonding is applied locally only to specific regions of the elastic member rather than uniformly across the entire member. The bonding locations are strategically positioned away from the edges where stress concentration would cause breakage, while still achieving sufficient bonding strength in the bonded regions.
Solution Approach 2:
The elastic member is stretched to the desired extent before the ultrasonic bonding process begins. This preliminary stretching ensures that the member is in its final configured state before bonding, allowing the bonding to lock in the stretched geometry without causing breakage during the bonding process itself.
2Productivity
If the elastic member is bonded immediately after extrusion in a stretched state, then production efficiency is improved, but the base material sheet surface remains flat instead of becoming uneven
Solution Approach 1:
The elastic member is extruded and stretched to the desired configuration before being bonded to the base material sheet. This preliminary preparation of the elastic member in its stretched state allows the subsequent bonding to occur efficiently without requiring additional stretching steps, while the stretched geometry of the elastic member then creates the desired surface unevenness on the base material 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
Prevents breakage of the elastic member during bonding and allows for the production of an elastic composite sheet with a surface that becomes uneven when the elastic member is released from the stretched state.
Implementation Method 1
bonding the elastic member to the first base material sheet, wherein for bonding ultrasonic bonding is used
Implementation Method 2
pass through a space between the stretching roller and a horn of an ultrasonic bonder
Data Source
Figure 1
Figure 2(a)~2(d)
Figure 3(a)~3(b)
AI summary
A production method of an elastic composite sheet is provided which makes it possible for the elastic member not to break when the elastic member, in a stretched state, is bonded to a base material sheet; an elastic composite sheet and a disposable wearable article using said elastic composite sheet are also provided. A strip-shaped or string-shaped elastic member (3) composed mainly of a thermoplastic elastic resin is stretched in the longitudinal direction of the elastic member (3). The stretched elastic member (3) is placed over a first base material sheet (4) such that the main surface of the first base material sheet (4) contacts the elastic member (3). In a state in which the stretched elastic member (3) and the first base material sheet (4) are placed over each other, the elastic member (3) and the first base material sheet (4) are bonded in a first position (60) that overlaps the elastic member (3) seen from a direction perpendicular to the main surface of the first base material sheet (4) and that is away from the edges (3p, 3q) of the elastic member (3).