Absorbent Body with Low-Basis-Weight Zone for Leakage Prevention

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Solution Overview

Problem

The groove in existing absorbent diapers disperses excreted fluid over a wide area and can cause deformation, leading to potential leakage from the longitudinal end portion, especially when the groove extends to the waist region.

Innovation Solution

An underpants-shaped absorbent article with a low-basis-weight portion in the central longitudinal direction and high-stiffness portions outside, where the absorbent body is folded and joined using adhesives, preventing deformation and leakage by dispersing urine effectively and maintaining structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the groove is formed to extend up to the waist region, then the absorbent body can be deformed to fit the crotch region, but leakage may occur from the longitudinal end portion due to bending deformation

Engineering Contradiction:
Improvedeformation capabilityVSAvoidleakage prevention
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The absorbent body is designed with non-uniform basis weight distribution, creating a low-basis-weight portion in the central longitudinal region that allows deformation, while high-basis-weight portions at the longitudinal end portions maintain structural integrity and prevent leakage. This local differentiation of material properties enables simultaneous deformation capability and leakage prevention.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The absorbent body is segmented into functional regions with different basis weights: the low-basis-weight central portion for deformation and the high-basis-weight end portions for structural support. This segmentation allows each region to perform its specific function without interfering with the other.

Inventive Principle:
Principle #1Segmentation

2Area of stationary object

If the groove extends in the longitudinal direction, then excreted fluid can be dispersed over a wide area, but the groove may cause bending deformation that reaches the longitudinal end portion

Engineering Contradiction:
Improvefluid dispersion areaVSAvoidstructural stability
Core Design Contradiction:
Area of stationary objectVSShape

Solution Approach 1:

The basis weight of the absorbent body is locally varied to create different mechanical properties in different regions. The low-basis-weight central region accommodates fluid dispersion and deformation, while the high-basis-weight end portions maintain structural stability and prevent bending deformation from reaching the edges.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the absorbent body is made more compliant for better fit, then it can deform to accommodate user movement, but it may fold and cause leakage at the longitudinal ends

Engineering Contradiction:
Improvefit adaptabilityVSAvoidend portion leakage prevention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The absorbent body employs spatially varying basis weight to create a gradient of mechanical compliance. The central low-basis-weight region provides compliance for fitting and deformation, while the high-basis-weight end portions provide rigidity to prevent folding and leakage, achieving both ease of operation and reliability.

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

The design induces deformation to fit the crotch region while suppressing leakage from the longitudinal end portion, ensuring effective urine dispersion and absorption without unnatural folds or wrinkles.

Implementation Method 1

a first joining portion in which a non-skin-side surface of an end portion of the absorbent main body on one side in the longitudinal direction is joined to the front waist portion using an adhesive; and a second joining portion in which a non-skin-side surface of an end portion of the absorbent main body on another side in the longitudinal direction is joined to the back waist portion using an adhesive

Methodology Applied
Scientific EffectAdhesive: Adhesive

Implementation Method 2

the absorbent body including a low-basis-weight portion in at least a central portion in the longitudinal direction, the low-basis-weight portion extending along the longitudinal direction, the low-basis-weight portion having a smaller basis weight than a surrounding area

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP3973936B1Underpants-shaped absorbent article
Publication Date: 2023.07.05 UNI CHARM CORP
  • EP3973936B1 patent drawingFigure 1
  • EP3973936B1 patent drawingFigure 2
  • EP3973936B1 patent drawingFigure 3

AI summary

An underpants-shaped absorbent article includes: a front waist portion (20); a back waist portion (30); an absorbent main body (10) that includes an absorbent body (11), a first joining portion (42) in which a non-skin-side surface of an end portion of the absorbent main body (10) on one side in the longitudinal direction is joined to the front waist portion (20) using an adhesive; and a second joining portion (44) in which a non-skin-side surface of an end portion of the absorbent main body (10) on another side in the longitudinal direction is joined to the back waist portion (30) using an adhesive. The absorbent body (11) includes a low-basis-weight portion (15) in at least a central portion in the longitudinal direction, the low-basis-weight portion (15) extending along the longitudinal direction and having a smaller basis weight than a surrounding area. A high-stiffness portion is provided in at least one of a longitudinal region extending from an inward end of the first joining portion (42) to an outward end of the low-basis-weight portion (15) and a longitudinal region extending from an inward end of the second joining portion (44) to another outward end of the low-basis-weight portion (15). The high-stiffness portion has a higher stiffness than the central position.