Absorbent Article Wrapping Sheet Adhesive Bonding

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Solution Overview

Problem

Absorbent articles, such as disposable diapers, face challenges in maintaining the shape of the absorbent body due to deformation issues like twisting and cracking, particularly at the edges and slits, which affect their functionality and durability.

Innovation Solution

The absorbent article incorporates a wrapping sheet with an increased usage of hot melt adhesive at the edges and slits, where deformation is most likely to occur, to enhance bonding and prevent shape distortion. This involves applying hot melt adhesive to the upper surface of the absorbent body before folding back the side parts of the wrapping sheet and bonding them, ensuring a stronger adhesive connection and minimizing the risk of shape deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If hot melt adhesive is applied uniformly across the entire surface of the absorbent body, then bonding strength is improved, but adhesive usage amount increases

Engineering Contradiction:
Improvebonding strengthVSAvoidadhesive usage amount
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The patent applies hot melt adhesive selectively to specific regions of the wrapping sheet rather than uniformly across the entire surface. The adhesive is concentrated at both end portions in the width direction and at slit portions where deformation is most likely to occur, providing localized bonding strength enhancement while minimizing overall adhesive consumption.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses partial action by applying adhesive only to critical areas (end portions and slit regions) rather than the entire surface. This partial application strategy provides sufficient bonding strength at deformation-prone locations without the excessive adhesive usage that would result from uniform full-surface application.

Inventive Principle:
Principle #16Partial or excessive action

2Stability of the object's composition

If adhesive usage is increased at critical regions, then shape deformation is suppressed, but manufacturing complexity increases

Engineering Contradiction:
Improveshape stabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The adhesive application system is designed to target specific local regions (end portions and slit areas) with higher adhesive concentration. This localized quality enhancement provides superior shape stability at critical deformation points without requiring complex manufacturing equipment, as the adhesive application can be achieved through targeted dispensing mechanisms.

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If the wrapping sheet is tightly bonded to the absorbent body, then shape maintainability is improved, but the absorbent body deformation resistance decreases

Engineering Contradiction:
Improveshape maintainabilityVSAvoiddeformation resistance
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent implements differential bonding strength across different regions of the absorbent body. At end portions and slit regions where shape maintenance is critical, tight bonding provides excellent shape maintainability. In the central region, reduced adhesive usage allows the absorbent body to maintain its natural deformation resistance, creating a balanced performance across different zones.

Inventive Principle:
Principle #3Local quality

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 configuration effectively suppresses shape deformation of the absorbent body by increasing adhesive strength at critical areas, improving the absorbent's stability and functionality, while minimizing the overall adhesive usage.

Implementation Method 1

a whole part of an internal surface of the wrapping sheet facing the absorbent body is bonded to an external surface of the absorbent body through a hot melt adhesive

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

a usage amount of the hot melt adhesive bonding the wrapping sheet and the absorbent body together is larger at least in a region of both end portions in a width direction on the other side of the absorbent body than on the one side of the absorbent body

Methodology Applied
Scientific EffectHot melt adhesive:

Data Source

PatentEP3357467B1Absorbent article and method for producing same
Publication Date: 2022.11.30 DAIO PAPER CORP
  • EP3357467B1 patent drawingFigure 1
  • EP3357467B1 patent drawingFigure 2
  • EP3357467B1 patent drawingFigure 3

AI summary

Shape deformation of an absorbent body is suppressed. Provided is an absorbent article characterized in that a wrapping sheet (58) wrapping an absorbent body (56) includes an intermediate part (56c) located on one side of front face side and back face side of the absorbent body (56) and both side parts (58s) folded back to the other side of the absorbent body (56) from the intermediate part (56c), distal ends of the both side parts (58s) of the wrapping sheet (58) are overlapped on the other side of the absorbent body (56) to form a connecting portion (58c), a whole part of an internal surface of the wrapping sheet (58) facing the absorbent body (56) is bonded to an external surface of the absorbent body (56) through hot melt adhesives (H1 and H2), and a usage amount of the hot melt adhesives (H1 and H2) bonding the wrapping sheet (58) and the absorbent body (56) together is larger at least in a region (A1) of both end portions in a width direction on the other side of the absorbent body (56) than on the one side of the absorbent body (56).