Absorbent article

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Solution Overview

Problem

Absorbent articles face challenges in simultaneously reducing residual liquid and sticky feelings on the skin, with existing liquid film cleavage agents often causing excessive stickiness when in contact with the skin in large amounts.

Innovation Solution

The absorbent article incorporates a topsheet with a liquid film cleavage agent, specifically compounds C1 and C2, arranged in a thickness intermediate position or on the absorbent body side, which have a spreading coefficient of 15 mN/m or more and low water solubility, and an interfacial tension of 20 mN/m or less, to effectively cleave liquid films and reduce residual liquid while minimizing skin contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a liquid film cleavage agent is applied to the skin-contact surface of the topsheet, then residual liquid is reduced, but sticky feeling on the skin increases

Engineering Contradiction:
Improveresidual liquidVSAvoidsticky feeling
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent applies liquid film cleavage agents to specific locations within the topsheet structure (thickness intermediate position or absorbent body side) rather than uniformly across the skin-contact surface. This localized application ensures the agents are positioned where they can effectively cleave liquid films and drain residual liquid without coming into direct contact with the skin, thereby eliminating the sticky feeling while maintaining liquid reduction effectiveness.

Inventive Principle:
Principle #3Local quality

2Productivity

If compounds with high spreading coefficient are used, then liquid film cleavage efficiency is improved, but water solubility increases causing skin irritation

Engineering Contradiction:
Improveliquid film cleavage efficiencyVSAvoidwater solubility
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent specifies precise parameter ranges for the liquid film cleavage agents: spreading coefficient of 15 mN/m or more (for effective liquid film cleavage) and water solubility of 0 g or more and 0.025 g or less (to prevent skin irritation). By carefully controlling these chemical parameters, the invention achieves effective liquid film cleavage while maintaining low water solubility to avoid excessive skin contact and irritation.

Inventive Principle:
Principle #35Parameter changes

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 achieves a balance by reducing residual liquid and preventing sticky feelings on the skin, enhancing dryness and comfort by promoting efficient liquid drainage and minimizing the agent's contact with the skin.

Implementation Method 1

compound C1 having a spreading coefficient of 15 mN/m or more to a liquid having surface tension of 50 mN/m

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Implementation Method 2

a liquid film formed in narrow interfibre spaces of the nonwoven fabric can be cleaved by a liquid film cleavage agent

Methodology Applied
Scientific EffectLiquid film cleavage: Surfactant

Implementation Method 3

bonding the first fibre layer and the second fibre layer by thermal fusion by heat treatment at a temperature higher than or equal to a melting point of the thermally fusible fibres

Methodology Applied
Scientific EffectThermal fusion: Melting

Data Source

PatentEP3639802B1Absorbent article
Publication Date: 2023.12.06 KAO CORP
  • EP3639802B1 patent drawingFigure 1~2
  • EP3639802B1 patent drawingFigure 3~4
  • EP3639802B1 patent drawingFigure 5~5(C)

AI summary

An absorbent article, containing a topsheet, a backsheet, and an absorbent body interposed between the topsheet and the backsheet, in which the topsheet has an arrangement portion of a liquid film cleavage agent in a thickness intermediate position.