Laminated Fabric Thermal Stability via Segmented EVA and Polyethylene Films
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High performance fabrics laminated with thermoplastic films, such as EVA, become soft and tacky at elevated temperatures, making them unsuitable for warm environments and prone to degradation, while polyethylene films do not provide sufficient bonding for certain applications.
Innovation Solution
A laminated fabric structure comprising a woven base layer of ultra-high molecular weight polyethylene yarns with an inner thermoplastic film of ethylene vinyl acetate (EVA) bonded to a polyethylene outer film, secured using heat and pressure to create a puncture and abrasion-resistant, air and water impervious layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If EVA thermoplastic film is used to bond to high performance fabric, then bonding strength is improved, but the laminate becomes soft and tacky at elevated temperatures
Solution Approach 1:
The patent divides the protective film into two separate layers: an inner EVA layer that provides bonding to the fabric, and an outer polyethylene layer that provides thermal stability. This segmentation allows each layer to perform its specific function without the limitations of a single-material film.
Solution Approach 2:
The patent creates a composite laminate structure combining EVA and polyethylene layers. The EVA layer (50-200 microns) bonds to the high performance fabric, while the outer polyethylene layer (25-500 microns) provides heat resistance and prevents tackiness at elevated temperatures, achieving properties that neither material alone could provide.
2Stability of the object's composition
If polyethylene film is used instead of EVA, then thermal stability is improved, but bonding strength to high performance fabric is insufficient
Solution Approach 1:
The patent assigns different functions to different layers: the inner EVA layer handles bonding to the fabric, while the outer polyethylene layer handles thermal stability. This functional segmentation resolves the contradiction by allowing each material to excel at its designated task.
Solution Approach 2:
The EVA layer acts as an intermediary between the high performance fabric and the polyethylene outer layer. It provides the necessary bonding interface to the fabric while allowing the polyethylene layer to provide thermal stability without direct contact requirements.
3Reliability
If vinyl-coated nylon is used for air and water impervious properties, then imperviousness is achieved, but high performance characteristics are lost
Solution Approach 1:
The patent combines high performance polyethylene fabric with thermoplastic film layers to create a composite that maintains the fabric's inherent cut and abrasion resistance while adding air and water imperviousness through the bonded film layers.
Solution Approach 2:
The patent uses thin thermoplastic film layers (EVA and polyethylene) bonded to the fabric to provide the impervious barrier function, allowing the high performance fabric to maintain its mechanical strength and flexibility without being coated with heavy vinyl 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 a durable, flexible laminate that maintains integrity and resistance to abrasion and punctures while remaining air and water impervious, even at elevated temperatures, without degrading into a tacky surface.
Implementation Method 1
secured and bonded by heat and pressure to the other side of the thermoplastic film
Implementation Method 2
EVA laminate becomes soft and tacky when exposed to temperatures above about 49°C (120°F)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A puncture and abrasion resistant, air and water impervious laminated fabric is provided. The laminated fabric includes a woven fabric base layer having warp and weft yarns, with at least 50 percent of the fibers in the warp yarns being formed of high performance material. A first thermoplastic film is bonded by heat and pressure to at least one of the sides of the fabric base layer. The first thermoplastic film is formed of ethylene vinyl acetate. A second thermoplastic film is bonded by heat and pressure to the first thermoplastic film on at least one of sides of the fabric. The second thermoplastic film is formed from either high density polyethylene or low density polyethylene.