Photo-Curable EVA Interlayer Film for Low Haze Laminated Glass
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Solution Overview
Problem
Conventional laminated glass interlayer films suffer from high haze and high production costs, with existing solutions either compromising on weather resistance or requiring lengthy production times.
Innovation Solution
A method involving an ethylene-vinyl acetate copolymer interlayer film is developed, incorporating specific additives such as photoinitiators, coupling agents, crosslink-assisting agents, radical scavengers, and ultraviolet light absorbers, which are mixed and processed at controlled temperatures to create a photo-curable interlayer film that is then sandwiched between glass sheets and cured under UV or visible light, reducing haze and production time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If peroxide cross-linking is used to improve penetration resistance and impact resistance, then strength is improved, but weather resistance and adhesion deteriorate
Solution Approach 1:
The patent changes the cross-linking mechanism from peroxide-based thermal cross-linking to silane-based moisture-curing cross-linking. This parameter change in the chemical reaction type eliminates the foaming issue while maintaining cross-linking density for strength, and produces a network structure that is compatible with glass surfaces for improved adhesion and weather resistance
Solution Approach 2:
The patent introduces silane coupling agents as intermediaries between the EVA copolymer and the glass surfaces. The silane groups react with both the polymer matrix and the glass surface, creating a bridging structure that simultaneously improves adhesion and enables controlled cross-linking without the harmful effects of peroxide cross-linking
2Reliability
If photo-cured EVA on PET film is used to improve adhesion and weather resistance, then reliability is improved, but haze increases and production cost increases
Solution Approach 1:
The patent extracts the PET film substrate from the interlayer structure, using only the photo-cured EVA copolymer as the interlayer material. This eliminates the inherent haze associated with PET films while retaining the advantages of photo-curing for adhesion and weather resistance
Solution Approach 2:
The patent optimizes the vinyl acetate content parameter in the EVA copolymer to a specific range (10-40 wt%) to balance transparency, adhesion, and cross-linking reactivity. This parameter optimization achieves low haze while maintaining the required performance properties
3Strength
If conventional PVB or cross-linked EVA is used as interlayer film, then safety and penetration resistance are improved, but production time is lengthy
Solution Approach 1:
The patent replaces thermal cross-linking processes with photo-curing technology. This substitution changes the curing mechanism from heat-dependent to light-dependent, enabling rapid cross-linking in minutes rather than hours, thus dramatically reducing production time while maintaining cross-linked strength and safety properties
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 method results in laminated glass with improved transparency, reduced haze, and significantly shorter production times, enhancing both quality and applicability while avoiding delamination issues.
Implementation Method 1
a photoinitiator, a coupling agent, a crosslink-assisting agent, an ultraviolet light absorber, and a radical scavenger to obtain a mixture; (C) forming the mixture at a specific temperature to obtain the laminated glass interlayer film
Implementation Method 2
an ultraviolet light absorber, wherein the amount of the photoinitiator ranges from 0.1 wt% to 10 wt%, the amount of the crosslink-assisting agent ranges from 0.1 wt% to 4 wt%
Implementation Method 3
a crosslink-assisting agent, wherein the crosslink-assisting agent comprises a polyfunctional compound containing an acrylic group or a vinyl group
Implementation Method 4
a radical scavenger, wherein the radical scavenger comprises a hindered phenol antioxidant or a hindered amine light stabilizer
Data Source
AI summary
A method in accordance with the present invention has: providing an ethylene-vinyl acetate copolymer; mixing the ethylene-vinyl acetate copolymer, a photoinitiator, a coupling agent, a crosslink-assisting agent, an ultraviolet light absorber, and a radical scavenger to obtain a mixture; and forming the mixture into a film at a specific temperature to obtain the laminated glass interlayer film. The laminated glass in accordance with the present invention is has high transmittance and low haze, and also shortens the production time, thereby enhancing the quality and applicability.