Multi-ply Waterproof Covering with Elastic Contraction

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Solution Overview

Problem

Existing stretchable and waterproof covering articles are costly and require frequent washing, necessitating the use of additional coverings or avoidance during activities like hand washing, cooking, and bathing, which is inconvenient for users.

Innovation Solution

A multi-ply stretchable waterproof sheet comprising a first air-permeable nonwoven fabric, a liquid diffusive sheet, an elastic member, a moisture-permeable film, and a second air-permeable nonwoven fabric, laminated in a specific order, with the elastic member applying an uneven surface contraction force to enhance moisture transpiration and reduce material costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a stretchable fabric and stretchable film are used to create a waterproof covering article, then waterproof performance and stretchability are improved, but manufacturing cost increases and washing maintenance is required

Engineering Contradiction:

Improvewaterproof performanceVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The covering article is divided into multiple functional layers: a water-permeable layer for breathability, a waterproof layer for water resistance, and an elastic layer for stretchability. Each layer is made from different materials optimized for its specific function, allowing the system to achieve waterproof performance without requiring expensive stretchable waterproof fabrics throughout the entire structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses a composite structure combining water-permeable materials (such as porous PTFE or expanded polypropylene) with elastic materials (such as spandex or rubber). This composite approach allows the waterproof layer to maintain water resistance while the elastic layer provides stretchability, avoiding the need for costly stretchable waterproof fabrics and reducing overall manufacturing cost.

Inventive Principle:

Principle #40Composite materials

2Reliability

If a stretchable fabric and stretchable film are used to create a waterproof covering article, then waterproof performance and stretchability are improved, but washing maintenance is required which reduces ease of operation

Engineering Contradiction:

Improvewaterproof performanceVSAvoidwashing maintenance

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The covering article is designed as a disposable product with a structure that can be manufactured at low cost. The multi-layer construction using inexpensive water-permeable and elastic materials allows the product to be discarded after use rather than requiring washing and maintenance, significantly improving ease of operation for users engaged in household work.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Adaptability or versatility

If a multi-layer structure with elastic member is used, then moisture transpiration and stretchability are improved, but device complexity increases

Engineering Contradiction:

Improvemoisture transpirationVSAvoidstructure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs thin film structures for the water-permeable and waterproof layers, which maintain flexibility and stretchability while providing the necessary barrier functions. The elastic layer incorporates elastic fibers or rubber components that provide stretchability without requiring a complex rigid structure, thus improving moisture transpiration and adaptability while keeping the overall structure relatively simple.

Inventive Principle:

Principle #30Flexible shells and thin films

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 a cost-effective, hygienic, and convenient covering article that remains effective during various activities by reducing material costs and maintaining hygiene without the need for frequent washing, while ensuring water resistance and sweat management.

Implementation Method 1

an elastic member (23), and a moisture-permeable film (24)... the elastic member (23) applying an uneven surface contraction force

Methodology Applied

Scientific EffectElastic contraction: Elasticity

Implementation Method 2

a moisture-permeable film (24)... ensuring water resistance and sweat management

Methodology Applied

Scientific EffectPermeation: Permeation

Implementation Method 3

a liquid diffusive sheet (22)... maintaining hygiene without the need for frequent washing

Methodology Applied

Scientific EffectLiquid diffusion: Diffusion

Data Source

PatentEP3593774B1Covering article

Publication Date: 2022.06.01 YAMADA CO LTD

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AI summary

In order to reduce a cost with a simple configuration, a covering article of the present invention includes: a liquid diffusive sheet having a property of diffusing absorbed liquid; a moisture-permeable film laminated on the liquid diffusive sheet; and a plurality of elastic members joined to at least one of the liquid diffusive sheet or the moisture-permeable film and arranged substantially in parallel, wherein a pair of opposing side edges are joined such that the plurality of elastic members are substantially annular, the liquid diffusive sheet is positioned closer to a skin of a user than the moisture-permeable film when the user wears, and the substantially annular elastic members press a wearing site of the user.