Absorbent Core Sealing for Constant Width

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Solution Overview

Problem

Conventional absorbent articles, such as diapers, tend to sag and lose comfort when wet due to inadequate liquid handling and manufacturing methods, leading to insufficient fit and function.

Innovation Solution

An absorbent article design featuring a specific sealing arrangement with ultrasonic welding patterns and a unique distribution of absorbent material across the core, including a center segment and side segments, to maintain constant energy transfer and prevent excessive expansion, thereby enhancing fit and comfort in wet conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the absorbent article uses conventional sealing arrangements during manufacturing, then the manufacturing process is simpler, but the energy transfer during welding varies along the absorbent core leading to inconsistent sealing quality

Engineering Contradiction:
Improvesealing consistencyVSAvoidsealing arrangement complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by varying the sealing spot dimensions along the longitudinal direction of the absorbent core. Specifically, the sum of the effective widths of sealing spots is configured to be larger at the crotch portion compared to the front and back portions. This localized adjustment compensates for the greater sagging tendency in the wet crotch area, ensuring consistent sealing quality and energy transfer throughout the article while maintaining manufacturing feasibility.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If the absorbent article absorbs body exudates, then liquid handling capability is improved, but the crotch portion sags and hangs down reducing comfort and fit

Engineering Contradiction:
Improveabsorbent capacityVSAvoidcrotch portion shape
Core Design Contradiction:
Quantity of substanceVSShape

Solution Approach 1:

The patent segments the absorbent core into distinct regions with different sealing characteristics. The crotch portion is separated from the front and back portions through specific sealing arrangements, allowing each segment to function independently. The crotch segment can expand to accommodate absorbed fluid while the front and back segments maintain their structural integrity, preventing overall sagging of the article.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements local quality by providing different sealing spot configurations in different regions of the absorbent core. The crotch portion has a larger sum of effective widths of sealing spots compared to the front and back portions. This localized structural reinforcement in the crotch area provides support to counteract sagging while allowing necessary expansion for fluid absorption, thus maintaining both absorbent capacity and shape stability.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If the sealing arrangement uses varying effective widths along the longitudinal axis, then sealing quality and fit are improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvesealing arrangement precisionVSAvoidmanufacturing ease
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by systematically varying the effective widths of sealing spots along the longitudinal axis of the absorbent core. The sum of effective widths is configured to be larger in the crotch portion and smaller in the front and back portions. This parameter variation can be implemented through programmable welding systems that adjust spot dimensions based on position, achieving precise sealing control while maintaining manufacturing efficiency through automated parameter adjustment.

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 improves the absorbent article's fit, comfort, and manufacturing efficiency by maintaining a consistent energy transfer during welding, reducing sagging and ensuring effective liquid handling, even in wet conditions.

Implementation Method 1

The sealing arrangement is constituted by a welding pattern, in particular produced by means of a ultrasonic welding

Methodology Applied
Scientific EffectUltrasonic welding: Ultrasonic Vibration

Data Source

PatentEP3727259B1Absorbent article with a sealing arrangement having constant width
Publication Date: 2023.11.15 ESSITY HYGIENE & HEALTH AB
  • EP3727259B1 patent drawingFigure 1
  • EP3727259B1 patent drawingFigure 2
  • EP3727259B1 patent drawingFigure 3

AI summary

The present disclosure relates to an absorbent article (1) comprising a liquid-permeable topsheet (3), a liquid-impermeable backsheet (4) and an absorbent core (5) sandwiched between said topsheet (3) and said backsheet (4), said article (1) being arranged along a longitudinal axis (y1) and a transversal axis (x1) extending in a perpendicular direction in relation to the longitudinal axis (y1) and said main article (1) defining a front portion (6), a back portion (7) and a crotch portion (8), wherein said absorbent core (5) is formed with a sealing arrangement (9, 10, 15, 16) comprising two channel sealings (9, 10) extending along said longitudinal axis (x1) in said crotch portion (8) and defining a first effective channel sealing width (w1) and a second effective channel sealing width (w2), respectively. Furthermore, the sealing arrangement (9, 10, 15, 16) comprises two side seams (15, 16) extending along two side edges (25, 26) of said core (5), said side seams (15, 16) defining a third and fourth effective width (w3, w4), respectively, along said crotch portion (8) and defining a fifth and sixth effective width (w5, w6), respectively, along said front portion (6) and back portion (7); said effective widths (w1, w2, w3, w4, w5, w6) being defined as the extension of said sealing arrangement (9, 10, 14, 15) in the transverse direction of the article (1), along any cross-section of the crotch portion (8), wherein the sum of said first to sixth effective widths (w1, w2, w3, w4, w5, w6) in the transversal direction is generally constant along said core (5).