Airlaid Sheet Material Latex Binder Distribution

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Solution Overview

Problem

Airlaid fibrous sheet materials stabilized with latex binders face challenges in achieving effective fluid handling while maintaining softness, flexibility, and desired strength and stability, as the latex binder can reduce fluid acquisition capacity and flexibility.

Innovation Solution

An airlaid sheet material is produced by applying a latex binder in a selected distribution to both surfaces of a fibrous web comprising cellulosic and synthetic fibers, with a ratio of the first amount to the second amount ranging from 2:1 to 4:1, and containing between 1% to 30% latex binder by weight, to achieve stability and fluid handling capabilities without compromising softness and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a latex binder is applied to the fibrous web to provide stability and strength, then the structural integrity is improved, but the fluid acquisition capacity and flexibility are reduced

Engineering Contradiction:
Improvestructural integrityVSAvoidfluid acquisition capacity
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The patent applies different amounts of latex binder to different surfaces of the fibrous web, with the first surface receiving a higher amount (2:1 to 4:1 ratio) than the second surface. This localized differentiation allows the first surface to have enhanced structural integrity where needed, while the second surface maintains better fluid acquisition capacity and flexibility by having less binder coating.

Inventive Principle:
Principle #3Local quality

2Strength

If a latex binder is applied to the fibrous web to provide stability and strength, then the structural integrity is improved, but the flexibility and softness are reduced

Engineering Contradiction:
Improvestructural integrityVSAvoidflexibility and softness
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

By applying latex binder in a non-uniform distribution with a 2:1 to 4:1 ratio between first and second surfaces, the patent creates localized zones of different mechanical properties. The first surface gains structural integrity from higher binder content, while the second surface retains flexibility and softness with lower binder content, thus resolving the contradiction between strength and ease of operation.

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If a latex binder is applied to the fibrous web to provide stability, then the structural integrity is improved, but the fluid handling capability is impaired

Engineering Contradiction:
Improvestructural stabilityVSAvoidfluid handling capability
Core Design Contradiction:
Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The differentiated latex binder application (2:1 to 4:1 ratio on first versus second surface) creates a gradient structure where the first surface has enhanced stability for structural support, while the second surface maintains higher fluid handling capability by having less binder interference, thus resolving the contradiction between stability and fluid handling capability.

Inventive Principle:
Principle #3Local quality

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 airlaid sheet material exhibits improved fluid handling and retention capacity, stability, and comfort due to the specific distribution of latex binder, maintaining high tensile strength and preventing gel blocking, while being soft and flexible.

Implementation Method 1

The airlaid sheet material is stabilized by means of a latex binder... applying a latex binder to the first surface and to the second surface of the fibrous layer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2524677B1An improved airlaid sheet material
Publication Date: 2014.08.06 PROCTER & GAMBLE CO
  • EP2524677B1 patent drawingFigure 1~2

AI summary

The present invention relates to an airlaid sheet material comprising a dry laid fibrous web and a latex coating on both surfaces thereof in selected amounts. The airlaid sheet material can be an absorbent structure for absorption of fluids.