Underpants Absorbent Article Side Bond Layout for Easier Tearing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional underpants-shaped absorbent articles face issues with tearing the waist opening after use, where the side joining portions can lead to unintended tearing or excessive stiffness, causing discomfort.

Innovation Solution

The absorbent article features a pair of waist portions joined by lateral joining regions with vertical extending heat-fusing portions, where the vertical gap between joining portions is wider than the joining portion length and narrower than the gap between heat-fusing portions, allowing easier tearing and reduced stiffness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional diaper or training pant is used, then absorbency is provided, but the article does not fit snugly against the body and allows urine to bypass the absorbent layer

Engineering Contradiction:
Improveurine containment reliabilityVSAvoidfit snugness
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The absorbent article is divided into distinct functional layers: a snug-fitting leg portion with elastic edges for body contact, and a separate absorbent layer positioned to receive urine. This segmentation allows each layer to optimize its specific function while working together to prevent urine bypass.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a three-dimensional configuration where the leg portion extends downward from the waist portion, creating a vertical dimension that envelops the body. This dimensional extension ensures snug contact and prevents urine from bypassing the absorbent layer through gaps.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the absorbent article is made to fit snugly against the body, then urine bypass is prevented, but the article may cause discomfort or difficulty in wearing

Engineering Contradiction:
Improveurine containment reliabilityVSAvoidwearing comfort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

Elastic edges are strategically positioned at specific locations (leg openings and waist portion) to provide localized snugness where needed for urine containment, while other areas maintain flexibility for comfort. This localized application of elasticity ensures reliable containment without causing overall discomfort.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The leg portion is designed to be flexible and adaptable, allowing it to dynamically conform to the body's contours while maintaining snug contact. This dynamic flexibility ensures comfortable wearing while preventing urine bypass through the leg area.

Inventive Principle:
Principle #15Dynamics

3Quantity of substance

If the absorbent layer is positioned to receive urine from the crotch area, then absorbency is maximized, but the article structure becomes complex

Engineering Contradiction:
Improveurine absorption capacityVSAvoidarticle structure complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The leg portion and absorbent layer are merged into a single integrated structure where the leg portion physically positions the absorbent layer in the optimal crotch area. This merging simplifies the overall structure compared to separate components while maintaining maximum absorbency capacity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The leg portion is pre-configured to extend downward from the waist portion, preliminarily positioning the absorbent layer in the correct location before urine contact. This preliminary structural arrangement ensures the absorbent layer is already in the optimal position to receive urine, eliminating the need for complex adjustment mechanisms.

Inventive Principle:
Principle #10Preliminary action

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

Easier tearing along the lateral inner ends of the joining portions post-use while minimizing the risk of excessive stiffness, enhancing user comfort and ease of removal.

Implementation Method 1

The leg portion (140) may have elastic edges that expand and contract to conform to a body contour.

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

An absorbent layer may be positioned to receive the urine

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 3

The leg portion (140) may extend downward from the waist portion (120) to envelop a lower portion of the body

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP4505983B1Underpants-type absorbent article
Publication Date: 2026.05.06 UNI CHARM CORP
  • EP4505983B1 patent drawingFigure 1
  • EP4505983B1 patent drawingFigure 2
  • EP4505983B1 patent drawingFigure 3

AI summary

Provided is an underpants-type absorbent article that is easy to tear along a bonding portion after usage, while decreasing the risk of a bonding region of a lateral end section of a waist part becoming excessively hard. In this underpants-type absorbent article (1) in which a pair of waist parts are bonded by a pair of bonding regions (SS) at both lateral end sections in the left-right direction, the bonding regions (SS) have a plurality of bonding portions (70) along the up-down direction, and at least one among one side sheet (21) and another side sheet (22) of the waist parts (20) has a plurality of thermally fused portions (EB) in which thermally fused fibers are bonded together. In an elongated state, a thermally fused portion row (R) along the up-down direction is formed by thermally fused portion groups that are adjacent to each other in the up-down direction and in which the center distance in the left-right direction is smallest. The thermally fused portions (EB) do not bond the one side sheet (21) and the other side sheet (22), but rather the interval between the bonding portions (70) in the up-down direction is wider than the length of the bonding portions in the up-down direction, and the interval between the bonding portions in the up-down direction is narrower than the interval between first thermally fused portions (EB1) and second thermally fused portions (EB2) of the thermally fused portion row (R).