Epoxy Coating Composition with HALS for UV Stability
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Solution Overview
Problem
Existing epoxy coating compositions for optical articles face challenges with photo-stability issues when exposed to UV rays and sunlight, particularly with absorbing dyes like perylene, coumarin, porphyrin, and acridine, leading to degradation and instability, especially at temperatures above 7°C, which affects their shelf life and performance.
Innovation Solution
A heat-curable epoxy composition incorporating a hindered amine light stabilizer, along with UV absorbers and antioxidants, is developed to enhance storage stability and photo-degradation resistance, comprising specific epoxy monomers and silane compounds, which maintains hardness, adhesion, and low haze while providing high light filtering efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If absorbing dyes (perylene, coumarin, porphyrin, acridine) are used in epoxy coating compositions to provide light filtering, then light filtering efficiency is improved, but photo-stability deteriorates when exposed to UV rays and sunlight
Solution Approach 1:
The patent introduces hindered amine light stabilizers (HALS) as intermediary substances that mediate between the absorbing dyes and harmful UV radiation. The HALS compounds act as sacrificial agents that absorb UV energy and free radicals, protecting the dye molecules from degradation while maintaining their light filtering functionality. This is achieved by adding 0.01-5% HALS to the epoxy coating composition containing the dyes.
Solution Approach 2:
The patent creates a composite coating system that combines epoxy resin with multiple functional components: absorbing dyes for light filtering, hindered amine light stabilizers for photo-protection, UV absorbers, and antioxidants. This composite formulation allows the system to simultaneously achieve light filtering efficiency, photo-stability, and storage stability by integrating the functions of different materials at molecular level.
2Ease of operation
If epoxy coating compositions are stored at temperatures above 7°C, then ease of operation is improved, but storage stability deteriorates leading to degradation and instability
Solution Approach 1:
The patent modifies the chemical composition parameters by incorporating hindered amine light stabilizers and antioxidants into the epoxy coating system. These additives change the chemical stability parameters of the formulation, enabling the coating to maintain stability at elevated storage temperatures (above 7°C) without premature curing or degradation. The HALS and antioxidants act as stabilizing agents that prevent polymerization and oxidation reactions during storage.
3Reliability
If UV absorbers and antioxidants are added to enhance photo-stability, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent employs hindered amine light stabilizers that perform multiple functions simultaneously: they act as UV absorbers, free radical scavengers, and antioxidants. This multi-functionality reduces the need for separate additives for each protective function, thereby limiting the increase in composition complexity while achieving comprehensive photo-stability protection.
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 composition achieves improved storage stability and photo-degradation resistance, maintaining performance even at room temperature, with enhanced abrasion and scratch resistance, and low cosmetic haze, while effectively filtering harmful blue light and UV radiation.
Implementation Method 1
at least one UV absorber
Implementation Method 2
at least one antioxidant, in particular at least one hindered amine light stabilizer
Implementation Method 3
at least one epoxy monomer having two or three epoxy groups... and at least one epoxy ring-opening catalyst
Implementation Method 4
at least one epoxy compound bearing at least one silicon atom having at least one hydrolyzable group directly linked to the silicon atom
Data Source
AI summary
The present invention relates to a heat-curable composition comprising at least one epoxy monomer having two or three epoxy groups, which is not a silicon compound having at least one hydrolyzable group directly linked to the silicon atom, at least one epoxy compound bearing at least one silicon atom having at least one hydrolyzable group directly linked to the silicon atom and at least one group comprising an epoxy function linked to the silicon atom though a carbon atom, and/or a hydrolyzate thereof, at least one epoxy ring-opening catalyst, and at least one compound comprising at least two (2,2,6,6-tetramethyl-4-piperidyl)- groups in which the nitrogen atom can be substituted with an alkyl group, an alkoxy group or an oxyl group.