Expandable-and-shrinkable member bonding for absorbent articles
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Solution Overview
Problem
Existing methods for producing absorbent articles with expandable-and-shrinkable members result in internal stress and warping due to uneven expansion and bonding issues, leading to potential detachment and irregular shapes that affect both the functionality and appearance of the product.
Innovation Solution
A method where the expandable-and-shrinkable member is attached to the web with increased expansion at the center and decreased expansion at the ends, and the end sections are covered by a cover sheet to enhance bonding and reduce visibility of irregular shapes, using techniques such as hot-melt adhesive, heat sealing, or ultrasonic bonding with colored or opaque materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the expandable-and-shrinkable member is expanded uniformly across the entire surface, then the bonding area is maximized, but internal stress causes warping and concavity on the expandable-and-shrinkable member side
Solution Approach 1:
The patent applies different expansion degrees to different regions of the expandable-and-shrinkable member. The center section is expanded to a greater degree than the end sections, creating local variation in expansion that reduces internal stress and prevents warping while maintaining sufficient bonding area. This is achieved by controlling the expansion process to create a gradient expansion pattern rather than uniform expansion.
2Strength
If the expandable-and-shrinkable member is pressed against the web during bonding, then bonding strength is improved, but the end sections are not sufficiently pressed resulting in inadequate bonding
Solution Approach 1:
The patent addresses the bonding issue at end sections by applying local quality principles. The cover sheet is specifically positioned to cover the end sections during the bonding process, ensuring that these areas receive adequate pressing and bonding treatment. This local intervention ensures uniform bonding quality across the entire expandable-and-shrinkable member, including the previously problematic end sections.
3Reliability
If the end sections are covered by a cover sheet during bonding, then bonding performance at ends is improved and irregular shapes are hidden, but the device complexity increases
Solution Approach 1:
The cover sheet serves multiple functions simultaneously: it protects the end sections during bonding, ensures adequate pressing and bonding at the end sections, and conceals any irregular shapes that may form. By combining these multiple functions into a single component, the patent avoids significantly increasing device complexity while achieving improved bonding performance and appearance.
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
This method improves bonding performance and minimizes irregularities, preventing detachment and enhancing the appearance of the absorbent article by ensuring stronger adhesion and hiding any irregular shapes.
Implementation Method 1
expandable-and-shrinkable members that are expandable and shrinkable in an expansion-and-shrink direction
Implementation Method 2
an adhesive is coated onto the expandable-and-shrinkable member and/or web, and the expandable-and-shrinkable member is pressed against the web to attach the elastic member to the web through the adhesive
Implementation Method 3
using techniques such as hot-melt adhesive, heat sealing, or ultrasonic bonding
Implementation Method 4
using techniques such as hot-melt adhesive, heat sealing, or ultrasonic bonding
Implementation Method 5
using techniques such as hot-melt adhesive, heat sealing, or ultrasonic bonding
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
The method for producing an absorbent article is to improve the bonding performance between an expandable-and-shrinkable member and web, and to improve product appearance. The method for producing an absorbent article includes a step of bonding a cover sheet (105) to a first continuous sheet (103) wherein a first sheet constituting the absorbent article is connected in a machine direction, or to a second continuous sheet (102) wherein a second sheet constituting the absorbent article is connected in the machine direction, a step of transporting the first continuous sheet in the machine direction while bonding an expandable-and-shrinkable member 11 that is expandable and shrinkable in the expansion-and-shrink direction so that the expansion-and-shrink direction is along the widthwise direction of the first sheet, with the center section 11a of the expandable-and-shrinkable member in a high-expanded state and the both end sections 11b on both sides of the center section in a low-expanded state, and a step of transporting each of the first continuous sheet and the second continuous sheet in the machine direction while successively bonding the first sheet and the second sheet. In the cover sheet bonding step, the cover sheet is bonded at locations corresponding to the both end sections so that the both end sections are covered by the cover sheet with the first sheet and the second sheet in a bonded state.