Absorbent Article Leakproof Compressed Portion Fluid Diffusion

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Solution Overview

Problem

Existing absorbent articles face leakage issues due to uneven fluid diffusion patterns, where body fluid easily diffuses backward from rear compressed portions or concentrates and overflows at the pointed tip of front grooves, leading to leakage from the end of the absorbent article.

Innovation Solution

A sanitary napkin design featuring a leakproof compressed portion with a depressed pattern that includes liquid induction, collection, and diffusion portions, arranged outside the body fluid discharging region, where the liquid induction portions are inverted V-shaped, guiding fluid to the centerline for collection and diffusion on both sides, preventing leakage by altering fluid direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If rear compressed portions are formed separately on both sides of the centerline, then body fluid absorption is improved, but body fluid diffuses backward through the gap between compressed portions causing leakage

Engineering Contradiction:
Improvebody fluid absorptionVSAvoidleakage prevention
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent merges the separate rear compressed portions into a continuous compressed portion that extends across the centerline. This continuous structure eliminates the gap between compressed portions, preventing body fluid from diffusing backward through the center while maintaining the absorption function on both sides.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The continuous compressed portion is designed with a front groove that creates segmented compression zones. The front groove portion provides a barrier effect that divides the fluid flow path, preventing backward diffusion while allowing lateral absorption. This segmentation within continuity resolves the contradiction between absorption and leakage prevention.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the center of the front groove projects forward in a continuous linear shape, then body fluid diffusion along the groove is improved, but body fluid concentrates at the pointed tip and overflows causing leakage

Engineering Contradiction:
Improvebody fluid diffusionVSAvoidleakage prevention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent modifies the symmetric continuous linear front groove by creating an asymmetric compressed portion design. The compressed portion extends beyond the front groove at specific locations, creating an asymmetric barrier that prevents fluid concentration at the tip while maintaining diffusion along the groove path.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent applies different compression qualities at different locations. The front groove provides a low-compression diffusion path, while the compressed portions at specific locations provide high-compression barriers. This local variation in compression quality allows fluid to diffuse along the groove but prevents overflow at critical points.

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If compressed portions are formed to maximize absorption capacity, then body fluid retention is improved, but uneven diffusion regions are created causing leakage

Engineering Contradiction:
Improvebody fluid retentionVSAvoiddiffusion region uniformity
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent uses a curved front groove design instead of straight lines. The arc-shaped front groove creates a smooth, continuous diffusion path that evenly distributes body fluid laterally. This curvature eliminates sharp angles and uneven diffusion regions, ensuring uniform fluid distribution while maintaining high absorption capacity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent varies the compression parameters (depth, width, spacing) of the compressed portions to optimize both absorption and diffusion uniformity. By adjusting these parameters, the compressed portions create consistent resistance to fluid flow, ensuring even diffusion across the absorbent article while maximizing retention capacity.

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

The design effectively changes the diffusion direction of body fluid, preventing leakage from the end of the absorbent article by ensuring fluid is collected and diffused laterally, thereby enhancing the absorbent's ability to manage fluid distribution without overflow or leakage.

Implementation Method 1

Body fluid absorbed into the absorber enters the voids between the fibers, and diffuses between the fibers by capillary action

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP3766466B1Absorbent article
Publication Date: 2024.02.21 DAIO PAPER CORP
  • EP3766466B1 patent drawingFigure 1
  • EP3766466B1 patent drawingFigure 2~3
  • EP3766466B1 patent drawingFigure 4

AI summary

According to the present invention, a leak-proof compressed part, which comprises indentations formed by indenting an absorber and which is for preventing leakage from an edge of the absorber by changing the direction of body fluid spreading from a region H corresponding to a body fluid discharge part, is formed outside the region H in a prescribed pattern. The leak-proof compressed part is provided with: a fluid guide section that is for guiding, toward a center line L extending from the proximal side toward the distal side of the region H, the body fluid spreading outward from region H, and that has portions that are disposed on both sides of the center line L so that the distance therebetween across the center line L becomes lesser from the proximal side toward the distal side of the region H; a fluid collecting section which is disposed on the center line L farther beyond the fluid guide section on the distal side of the region H and which is for collecting the body fluid guided by the fluid guide section; and a fluid spreading section which extends from the fluid collecting section to both sides of the center line L and which is for spreading the collected body fluid toward both sides of the center line L.