Absorbent Belted Article Friction Control

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Solution Overview

Problem

Belted-absorbent articles face attachment issues due to varying friction coefficients between the pad and belt, leading to potential separation when moved relative to surroundings, such as bedclothes or trousers, resulting in poor performance and leakage.

Innovation Solution

The absorbent belted-article is designed with a chassis comprising a liquid-permeable top sheet and a liquid-impermeable back sheet, where the kinetic coefficient of friction between the back sheet of the pad and the outwardly oriented surface of the belt is maintained within a narrow range (0.2 to 0.5) to ensure consistent attachment, using materials like nonwoven layers and hook/loop attachments to minimize detachment risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the belt and pad are made from different materials to provide functional differentiation, then the functional performance is improved, but the difference in kinetic coefficients of friction increases causing attachment failure

Engineering Contradiction:
Improvefunctional performanceVSAvoidattachment stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies parameter changes by carefully selecting and adjusting the kinetic coefficient of friction values for different materials. The back sheet material is chosen to have a kinetic coefficient of friction between 0.2-0.5, while the belt material is selected to have a kinetic coefficient of friction between 0.3-0.8, ensuring the difference remains within 0.5. This quantitative parameter control allows functional differentiation while maintaining attachment reliability during movement.

Inventive Principle:
Principle #35Parameter changes

2Strength

If high friction materials are used to prevent slipping during movement, then the attachment strength is improved, but the differential friction between belt and pad causes relative movement and detachment

Engineering Contradiction:
Improveattachment strengthVSAvoidattachment consistency
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies homogeneity by ensuring that the friction characteristics of the belt and pad materials are closely matched. By controlling the kinetic coefficient of friction difference to be within 0.5, the patent creates homogeneous friction behavior between the two components. This homogeneous friction response ensures that both belt and pad move together as a unit during relative movement with surroundings, preventing detachment while maintaining consistent attachment strength.

Inventive Principle:
Principle #33Homogeneity

3Ease of manufacture

If the kinetic coefficient of friction difference between belt and pad is large, then the individual material performance is optimized, but the reaction forces during movement cause separation

Engineering Contradiction:
Improvematerial selection flexibilityVSAvoidseparation force
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by establishing specific numerical ranges for the kinetic coefficients of friction. The back sheet material is constrained to have μk between 0.2-0.5, and the belt material is constrained to have μk between 0.3-0.8, with the difference limited to maximum 0.5. These quantitative parameter specifications allow manufacturers to select from multiple material options within the defined ranges, maintaining both manufacturing flexibility and performance reliability by controlling the reaction forces during movement.

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 design ensures that the belt and pad remain attached during movement, preventing separation and maintaining effective absorption, even with significant external forces, as demonstrated by reduced reaction forces acting on the attachment, thus enhancing the article's performance and preventing leakage.

Implementation Method 1

the difference in kinetic coefficients of friction measured under ASTM D 1894-08 Standard between the back sheet of the pad and the outwardly oriented surface of the belt is maximum 0.5

Methodology Applied
Scientific EffectKinetic friction: Friction

Data Source

PatentEP2736473B1An absorbent belted article wherein the belt and the absorbent pad have specific kinetic coefficients of friction
Publication Date: 2016.04.20 SCA HYGIENE PRODUCTS AB
  • EP2736473B1 patent drawingFigure 1
  • EP2736473B1 patent drawingFigure 2~3
  • EP2736473B1 patent drawing

AI summary

An absorbent article comprising an absorbent pad and a belt to which the pad is detachably attached and which is intended to be attached to a separate belt that is placed around the waist of the wearer to hold the pad when the article is being worn, wherein the absorbent pad exhibits a chassis comprising a liquid-permeable top sheet and a liquid-impermeable back sheet oriented away from the wearer and an absorbent core between the top sheet and the back sheet. The difference in kinetic coefficients of friction measured with ASTM D 1894-08 standard between the back sheet of the pad and the outwardly oriented surface of the belt is at maximum 0.5. The attachment between the belt and the pad will then not cease due to the movement of the article relative to the surroundings when the belted-article is being used, thereby preventing contamination and leakage caused by detachment.