ETFE Copolymer Film Composition for Low-Haze UV Reflection Control
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Solution Overview
Problem
Conventional ethylene-tetrafluoroethylene copolymer films exhibit high haze, leading to milky white appearance and reduced transparency, and high ultraviolet reflectance, causing eye discomfort and unclear views, while being prone to scratches and reflections.
Innovation Solution
A film comprising a copolymer with specific haze, ultraviolet reflectance, and thickness, produced through controlled cooling and composition, including tetrafluoroethylene and ethylene units, with optional additional monomers and UV absorbers, to enhance designability and eye-friendliness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ethylene-tetrafluoroethylene copolymer film is used, then weather resistance and mechanical strength are improved, but haze increases causing milky white appearance and reduced transparency
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ratio of tetrafluoroethylene and ethylene units (specifically 40-60 mol% tetrafluoroethylene), molecular weight distribution, and crystallinity level to achieve the optimal balance between weather resistance and transparency. By adjusting these parameters, the film attains haze of 2.0% or less while maintaining excellent weather resistance inherent to fluoropolymers.
Solution Approach 2:
The patent employs composite material strategy by incorporating UV absorbers (such as benzotriazole or triazine derivatives) into the ethylene-tetrafluoroethylene copolymer matrix. This composite approach enhances both the optical clarity and UV protection capabilities, reducing haze and preventing the milky white appearance while maintaining the base polymer's weather resistance.
2Strength
If conventional ethylene-tetrafluoroethylene copolymer film is used, then mechanical strength is improved, but ultraviolet reflectance increases causing eye discomfort and unclear views
Solution Approach 1:
The patent converts the potentially harmful high UV reflectance into a benefit by incorporating UV absorbers that capture UV radiation and convert it into harmless thermal energy. The UV absorbers (benzotriazole or triazine derivatives) absorb UV rays before they can be reflected back, transforming the harmful reflection into beneficial UV protection while maintaining mechanical strength.
Solution Approach 2:
The patent adjusts the UV reflectance parameter by optimizing the copolymer composition and adding UV absorbers, reducing UV reflectance to 30% or less. This parameter change eliminates eye discomfort and glare while preserving the mechanical strength provided by the fluoropolymer structure.
3Strength
If film thickness is increased to improve mechanical strength, then strength is improved, but haze increases reducing transparency
Solution Approach 1:
The patent resolves this contradiction by changing the crystallinity parameter of the copolymer. By controlling crystallinity to be 40% or less through specific composition ratios and processing conditions, the film maintains high transparency even at increased thickness. This allows mechanical strength to be enhanced through thickness without the proportional increase in haze that would normally occur.
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 film achieves clear visibility, inconspicuous scratches, and reduced eye strain, with improved designability and mechanical strength, suitable for membrane structures.
Implementation Method 1
an ultraviolet reflectance of less than 17.0%
Implementation Method 2
the film has a haze of from 1.2% to 8.0%
Data Source
AI summary
A film includes a copolymer having a tetrafluoroethylene-based unit and an ethylene-based unit, in which the film has a haze of from 1.2% to 8.0%, an ultraviolet reflectance of less than 17.0%, and a thickness of from 250 to 400 μm.