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、(PDF) Aging and yellowing of triterpenoid resin
It appears that the polymer acts as a natural radical stabilizer, favoring the pronounced intrinsic yellowing tendency of mastic. The manipulation of resin composition might lead to improved...
3、Preventing yellowing in epoxy resins cured with Trimethyl hexamethylene
High Exotherm Temperature: The curing reaction between the epoxy resin and the amine hardener is exothermic (releases heat). In large castings or if the ambient temperature is high, this heat can accumulate, causing the internal temperature to rise significantly.
4、Terpene Resin Yellowing Resistance
It is worth noting that hydrogenated terpene resin typically exhibits superior non-yellowing properties compared to hydrogenated rosin resin. Terpene resin inherently possesses good resistance to yellowing, and this characteristic is further enhanced after hydrogenation modification.
The Yellowing Issue of Epoxy Resins and Curing Agents
The yellowing of epoxy resin is a complex issue influenced by its chemical structure, curing agents, exposure to light and heat, and the presence of impurities.
Why Epoxy Resin Is Prone to Yellowing: A Comprehensive Analysis
The presence of free amines in the curing agent can lead to localized heating during the curing process, which accelerates the oxidation and yellowing of the resin.
Yellowing mechanisms of epoxy and vinyl ester resins under
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.
Epoxy Yellowing: What It Is and How to Stop It
Heat Exposure: High temperatures can accelerate the yellowing process, even without direct UV exposure. Thermal degradation can break down polymer chains in a similar way to UV light, leading to the formation of color-causing chromophores.
Yellowing mechanisms of epoxy and vinyl ester resins under
This paper presents an experimental study on the yellowing mechanisms of epoxy and vinyl ester resins under thermal, UV and natural aging conditions. Anti-yellowing methods including air isolation, antioxidant, UV absorber are selected and their effectiveness is assessed.
Aging and yellowing of triterpenoid resin varnishes – Influence of
The key results on the influence of conditions and resin composition on aging and yellowing of triterpenoid varnishes are presented here. The complete set of analytical data obtained from all resins in all experiments may be found in the thesis of Dietemann [14].
In modern industry, terpene resins, as an important synthetic material, are widely used in various fields such as plastics, rubber, coatings, and more. the yellowing phenomenon that occurs when terpene resins are heated not only affects the appearance of the products but may also negatively impact their quality and performance. This article will delve into the causes of yellowing in terpene resins during heating and propose corresponding solutions.
I. Analysis of the Causes of Yellowing in Terpene Resins During Heating
1. Poor Quality of Raw Materials
The source of raw materials directly affects the performance of terpene resins. If the raw materials contain a high level of impurities, such as excessive unsaturated fatty acids or aromatic compounds, these impurities can easily oxidize or polymerize at high temperatures, leading to yellowing of the resin. Additionally, metal ions in the raw materials may also cause discoloration. For example, ferrous ions can react with carboxylic groups in the resin at high temperatures, forming complexes that result in yellowing.
2. Improper Processing Conditions
The processing conditions of terpene resins significantly influence their color. During heating, if the temperature is too high or the heating time is excessively long, unstable components in the resin may undergo thermal decomposition or polymerization reactions, causing yellowing. improper use of catalysts can also lead to color changes. For instance, certain catalysts may accelerate the oxidation of unsaturated fatty acids, resulting in yellowing.
3. Impact of Storage and Usage Environment
The storage and usage environment of terpene resins can also contribute to color changes. For example, ultraviolet (UV) light exposure can induce photooxidation of unsaturated fatty acids in the resin, leading to yellowing. High humidity may cause the resin to absorb moisture, resulting in discoloration. Additionally, prolonged exposure to air can lead to the evaporation of volatile substances in the resin, leaving residues that may also cause yellowing.
II. Measures to Address the Yellowing of Terpene Resins During Heating
1. Optimize Raw Material Selection
When selecting raw materials for terpene resins, strict quality control standards should be applied, prioritizing high-purity materials with minimal impurities. A multi-source procurement strategy can ensure diversity and stability of raw materials. For raw materials containing metal ions, impurity removal processes should be implemented to reduce their impact on resin color.
2. Improve Processing Techniques
During the processing of terpene resins, temperature and time should be strictly controlled to avoid overheating and extended heating periods. Additives such as antioxidants and stabilizers can be incorporated to inhibit color changes during processing. Catalysts with minimal impact on resin color should also be selected.
3. Enhance Storage and Usage Conditions
To slow color changes in terpene resins, storage areas should be protected from light and humidity, with controlled temperature and humidity. When using terpene resins, avoid prolonged exposure to air and promptly clean surface dust and contaminants. For long-term storage, regular inspections and maintenance should be conducted to ensure stable performance.
4. Strengthen Testing and Monitoring
A comprehensive quality detection system for terpene resins should be established, with real-time monitoring of critical parameters during production. Techniques such as infrared spectroscopy and chromatography can be used for rapid and accurate qualitative and quantitative analysis of resin samples to promptly identify and resolve color change issues. Additionally, intensified sampling inspections of products in circulation should be carried out to ensure consistent product quality.
The yellowing of terpene resins during heating is a complex issue involving multiple factors, including raw materials, processing, storage, and usage. To address this problem, it is essential to start with the source: strictly control raw material quality, optimize processing techniques, improve storage and usage conditions, and strengthen testing and monitoring. Only by doing so can the color stability of terpene resins be ensured, meeting the demands of industrial production.
