Flash-Spun Barrier Sheet Structure for Breathable Water Resistance

Solution Overview

Problem

Existing composite fabrics for protective apparel and construction materials face challenges in achieving a balanced combination of breathability, mechanical strength, and liquid barrier properties, often compromising on surface robustness, comfort, and noise levels.

Innovation Solution

A thermally bonded sheet of nonwoven flash-spun plexifilamentary fibrils with specific properties, including basis weight, particle filtration efficiency, hydrostatic head, and moisture vapor transmission rate, is produced by generating a spin fluid with a polymer and solvent mixture, flash spinning, and embossing to create a bonded sheet.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a flash-spun sheet is made from hydrophobic microfibers to provide water resistance, then water repellency is improved, but breathability deteriorates because the hydrophobicity prevents moisture vapor transmission

Engineering Contradiction:

Improvewater resistanceVSAvoidbreathability

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating distinct regions within the nonwoven structure: hydrophobic microfibers in certain areas provide water resistance, while hydrophilic pores and capillary channels in other areas enable moisture vapor transmission. This spatial differentiation of material properties allows simultaneous achievement of water repellency and breathability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining hydrophobic microfibers with hydrophilic pore structures and capillary channels within the same nonwoven sheet. This composite structure integrates materials with opposing properties to achieve both water resistance and moisture vapor transmission capability.

Inventive Principle:

Principle #40Composite materials

2Strength

If the nonwoven structure is made denser to improve strength and durability, then mechanical strength is improved, but breathability deteriorates because fewer pores are available for moisture vapor transmission

Engineering Contradiction:

Improvemechanical strengthVSAvoidbreathability

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating distinct regions within the nonwoven structure: hydrophobic microfibers in certain areas provide water resistance, while hydrophilic pores and capillary channels in other areas enable moisture vapor transmission. This spatial differentiation of material properties allows simultaneous achievement of water repellency and breathability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs porous materials by incorporating hydrophilic pores and capillary channels throughout the nonwoven structure. These pores are strategically distributed to maintain mechanical strength while providing pathways for moisture vapor transmission, resolving the contradiction between density and breathability.

Inventive Principle:

Principle #31Porous materials

3Object-affected harmful factors

If hydrophobic microfibers are used to provide water resistance, then water repellency is improved, but comfort deteriorates because moisture vapor cannot be transmitted through the material

Engineering Contradiction:

Improvewater resistanceVSAvoidcomfort

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent applies local quality by creating distinct regions within the nonwoven structure: hydrophobic microfibers in certain areas provide water resistance, while hydrophilic pores and capillary channels in other areas enable moisture vapor transmission. This spatial differentiation of material properties allows simultaneous achievement of water repellency and breathability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining hydrophobic microfibers with hydrophilic pore structures and capillary channels within the same nonwoven sheet. This composite structure integrates materials with opposing properties to achieve both water resistance and moisture vapor transmission capability.

Inventive Principle:

Principle #40Composite materials

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 solution provides enhanced surface robustness, nail tear resistance, and breathability while maintaining high barrier properties, ensuring comfort and durability in protective apparel and construction applications.

Implementation Method 1

a three-dimensional matrix of hydrophilic pores and capillary channels

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

hydrophilic pores and capillary channels that are accessible from the surface of the nonwoven structure

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 3

flash-spun sheet made from hydrophobic microfibers

Methodology Applied

Scientific EffectHydrophobicity: Hydrophobe

Data Source

PatentEP4713518B1High barrier breathable flash-spun sheet

Publication Date: 2026.04.29 DUPONT SAFETY & CONSTRUCTION INC

AI summary

The present invention relates to (i) a bonded sheet of nonwoven flash-spun plexifilamentary fibrils exhibiting good barrier properties, a high degree of breathability, good surface robustness and mechanical strength, including nail tear resistance, (ii) a process for the preparation of a bonded sheet of nonwoven flash-spun plexifilamentary fibrils, and (iii) a multilayer sheet structure and an article comprising the bonded sheet of nonwoven flash-spun plexifilamentary fibrils.