1、Yellowing mechanisms of epoxy and vinyl ester resins under thermal, UV
Polymer resins have yellowing issue when subjected to elevated temperatures or UV exposure, which limit their applications in color-sensitive fields. This paper presents an experimental study on the yellowing mechanisms of epoxy and vinyl ester resins under thermal, UV and natural aging conditions.
2、Effect of anti
In this article, we’ll explore how varying concentrations of anti-yellowing agents affect both the curing behavior and visual characteristics of epoxy systems.
3、Yellowing
Yellowing-resistant epoxy curing agents, a key component in epoxy resin applications, significantly influence the cured properties of epoxy systems. This article explores the importance, mechanisms, performance indicators, and practical considerations of yellowing-resistant epoxy curing agents.
4、Yellowing of Epoxy Resin Anhydride Curing Agents
Abstract Epoxy resins can be cured with a wide variety of curing agents such as amines and anhydrides, but anhydride curing would be more favorable for research purpose because of epoxy-anhydride curing taking place slowly at room temperature.
Curing reactions of epoxy powder coatings in perspectives of chemical
The properties of the cured products of epoxy powder coatings are dominated by the curing systems. This review discusses the types, reaction principles, characteristics of curing agents and accelerators that participate in the curing reaction with different epoxy resins.
Novel Curing Agent for High
This novel curing agent retains gloss and staves off yellowing better than commercial products. The result of the accelerated weathering test shows it gives the lowest yellowing and the highest gloss retention.
Anti
Aliphatic diamines and polyamines are long used as important curing agents for epoxy resins, especially in room-temperature-cure epoxy coatings and adhesives due to their high reactivity and low cost.
Investigating the effectiveness of anti
This article dives into the science behind yellowing in UV-cured epoxies, explores the various types of anti-yellowing agents available, evaluates their performance through real-world testing, compares them across different formulations, and offers practical insights for their use in industry.
Epoxy resin composition resistant to high
Problems solved by technology In order to obtain a light- colored resin layer, alicyclic amine curing agents are often used. On the one hand, the color of this type of curing agent itself is relatively light, and on the other hand, this type of curing agent has better yellowing resistance.
What Are the Yellowing
Imidazoline curing agents are a new class of epoxy curing agents that cure resins by reacting with hydroxyl groups to form stable imidazoline rings. They offer good thermal stability, yellowing resistance, and cost-effectiveness.
In modern industry, epoxy resin is widely used across various fields due to its excellent mechanical properties, chemical stability, and electrical insulation. as temperatures rise, epoxy resin materials may undergo a phenomenon known as high-temperature yellowing, which severely impacts their appearance and performance. This article explores the causes and effects of high-temperature yellowing and discusses how to mitigate this issue through improved curing agents.
Principles of High-Temperature Yellowing
At elevated temperatures, molecular chains within epoxy resin move more intensely, weakening intermolecular forces and causing structural relaxation. Additionally, high temperatures may induce decomposition or oxidation of certain components in the resin, further compromising its structural integrity. These changes lead to a color shift from transparent to yellow or brown, resulting in the so-called high-temperature yellowing.
Impacts of High-Temperature Yellowing
- Aesthetic Issues: High-temperature yellowing causes uneven yellow streaks or spots on epoxy products, significantly reducing their visual appeal and perceived quality.
- Performance Degradation: Beyond aesthetics, yellowing can affect critical properties such as mechanical strength, electrical performance, and weather resistance. For example, color variations may lead to inaccuracies in electronic devices, compromising precision and reliability.
- Increased Costs: Material waste and rework caused by yellowing raise production costs and lower overall economic efficiency.
Controlling High-Temperature Yellowing
To effectively manage high-temperature yellowing, the key lies in selecting appropriate curing agents. Common strategies include:
- Heat-Resistant Curing Agents: Developing new high-temperature-resistant curing agents (e.g., compounds with specific functional groups) enhances the resin’s thermal tolerance.
- Optimized Formulation Ratios: Adjusting the resin-to-curing agent ratio reduces the presence of heat-sensitive components, improving thermal stability.
- Auxiliary Additives: Incorporating antioxidants, UV absorbers, and other additives slows down thermal aging processes at high temperatures.
- Microwave Curing Technology: This technique enables rapid curing at lower temperatures, minimizing material deformation and yellowing.
- Strict Process Control: Rigorous monitoring of temperature, time, and other parameters during production ensures optimal curing conditions.
High-temperature yellowing is a common challenge for epoxy resins under specific conditions, affecting both product quality and economic efficiency. By selecting suitable curing agents, optimizing formulations, adding auxiliary agents, and adopting advanced curing technologies, high-temperature yellowing can be effectively controlled. This improves the performance and market competitiveness of epoxy products. For engineers and technicians working with epoxy resins, mastering these strategies is crucial for successful application development.
