ETFE Sheet Extrusion for Strength and Transparency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional ETFE sheets used for large membrane panels lack sufficient mechanical strength while maintaining transparency, and increasing thickness to enhance strength leads to defects and reduced productivity.
Innovation Solution
An ETFE sheet with a thickness of 305 to 3000 μm, produced by extrusion using a process involving a rigid and elastic roll setup, where the ETFE melt is cooled under controlled pressure and temperature conditions, ensuring low in-plane phase difference and high luminous transmittance, and meeting specific acoustic and tensile stress requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of the ETFE sheet is increased to enhance mechanical strength, then the tensile stress at yield improves, but the light transmittance decreases and outer appearance becomes insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the cooling temperature range (50-180°C) and pressure conditions during extrusion to achieve optimal crystallinity and molecular orientation. This resolves the contradiction by enabling thick sheets (305-3000 μm) to maintain both high tensile stress and adequate light transmittance through controlled physical parameters during manufacturing
2Strength
If the thickness of the ETFE sheet is increased to enhance mechanical strength, then the tensile stress at yield improves, but the outer appearance develops defects due to high weight
Solution Approach 1:
The patent changes the temperature and pressure parameters during the extrusion process to prevent defects in thick sheets. By maintaining cooling temperatures between 50-180°C and controlling the linear pressure (0.1-1000 N/cm), the process enables production of defect-free surfaces even in sheets up to 3000 μm thick, resolving the contradiction between strength enhancement and appearance quality
Solution Approach 2:
The patent introduces an intermediary cooling mechanism using controlled temperature rolls as a mediator between the hot extruded melt and the final product. This intermediary cooling process prevents thermal shock and surface defects while allowing thick sheets to be produced with excellent appearance quality and high mechanical strength
3Manufacturing precision
If compression molding method is used to produce thick ETFE sheets with fewer defects, then the outer appearance improves, but the productivity decreases
Solution Approach 1:
The patent replaces the traditional compression molding mechanical system with a continuous extrusion system. By substituting the batch-process compression molding with a continuous extrusion process featuring controlled cooling rolls, the method achieves both high productivity and defect-free thick sheets, resolving the contradiction between manufacturing precision and production efficiency
4Strength
If multiple ETFE sheets are overlaid to improve mechanical strength, then the tensile stress increases, but the transparency decreases due to interfacial reflection
Solution Approach 1:
The patent transitions from a multi-layer stacking approach (adding layers in the z-dimension) to a single-thickness extrusion approach (controlling thickness in the z-dimension directly). By extruding sheets in the range of 305-3000 μm as single layers with controlled crystallinity, the method achieves high mechanical strength without the transparency loss from multiple interfaces, resolving the contradiction between strength and transparency
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 process results in an ETFE sheet with enhanced mechanical strength, transparency, and sound insulation properties, suitable for large membrane panels without compromising appearance or productivity.
Implementation Method 1
letting the sheet pass between two rolls as a pair and cooling the sheet
Implementation Method 2
the average of the surface temperatures of the two rolls is from 50 to 180°C
Implementation Method 3
one of the two rolls is a rigid roll, and the other is an elastic roll
Implementation Method 4
RaId (wherein R0 is an in-plane phase difference, and d is a thickness) of at most 3.0×10^-3
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
To provide an ethylene/tetrafluoroethylene copolymer sheet excellent in the mechanical strength and the outer appearance, continuously produced by extrusion, and a process for producing it. An ethylene/tetrafluoroethylene copolymer sheet obtained by extrusion, which is characterized by having Ro/d (wherein Ro is an in-plane phase difference [unit: nm], and d is a thickness [unit: nm]) of at most 3.0×10-3, and a thickness of more than 300 µm, and a process for producing it.