Waterproof-Breathable Film Polymer Composition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing breathable films face challenges in achieving both high water vapor permeability and good processability during manufacturing, particularly during extrusion, due to limitations in stretchability and deformations.
Innovation Solution
A composition comprising 75% to 98% hydrophilic thermoplastic elastomer polymer A, 2% to 15% copolymer B derived from ethylene, alkyl (meth)acrylate, and a comonomer with reactive functions, and optional additives, which allows for the production of films with enhanced permeability and processability through extrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyamide blocks and polyether blocks are used to form breathable films, then high permeability to water vapor is achieved, but the films are sparingly stretchable and difficult to process during extrusion
Solution Approach 1:
The patent uses a composite material system consisting of polyether block amide (PEBA) thermoplastic elastomer combined with poly(ethylene-co-vinyl acetate-g-maleic anhydride) polymer. This composite allows the film to maintain high water vapor permeability from the PEBA while gaining improved processability and stretchability from the polyethylene-based copolymer, resolving the contradiction between breathability and manufacturability
Solution Approach 2:
The patent modifies the chemical composition parameters by incorporating maleic anhydride functional groups into the polyethylene copolymer at controlled levels (0.1% to 2% by weight). This parameter change enables reactive interactions with the PEBA blocks, improving adhesion and processability while preserving the breathability characteristics of the polyether segments
2Ease of manufacture
If terpolymer compositions derived from ethylenic, acrylic and butylenic monomers are used, then films are readily processable by extrusion, but the films have very low breathability
Solution Approach 1:
The patent merges two distinct polymer systems: the processable poly(ethylene-co-vinyl acetate-g-maleic anhydride) copolymer and the breathable polyether block amide. By combining these materials in specific ratios (75% to 98% PEBA and 2% to 15% polyethylene copolymer), the invention achieves both good processability and high breathability, counteracting the low breathability issue of conventional terpolymers
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 enables the manufacture of films with excellent water vapor permeability and improved processability, specifically during extrusion, resulting in stable and high-quality products.
Implementation Method 1
copolymer B comprising units derived from ethylene, from an alkyl (meth)acrylate and from a comonomer including at least one acid, anhydride or epoxide function
Data Source
AI summary
The invention relates to a composition consisting of 75 to 98 wt %, relative to the weight of the composition, of at least one hydrophilic elastomeric thermoplastic polymer (TPE) A selected from (a1) copolymers containing polyester blocks and polyether blocks, (a2) copolymers containing polyurethane blocks and polyether blocks or polyester blocks and/or mixtures thereof; 2 to 15% by weight, relative to the weight of the composition, of at least one copolymer B comprising units derived from ethylene, from an alkyl (meth)acrylate and from a comonomer comprising at least one acid, anhydride or epoxide function; and 0 to 10% by weight, relative to the weight of the composition, of at least one additive. The invention further relates to a process for manufacturing a film and to said film.