High-Temperature Resistant Varnish: A Reliable Solution for the Printing Industry

1. Definition and Principle

High-temperature resistant varnish is a special coating material that can maintain stable performance in high-temperature environments. Its main components include heat-resistant resins, photoinitiators, diluents, and additives. After being coated on the surface of an object, it quickly cures into a hard protective layer under ultraviolet light, effectively protecting the substrate surface from discoloration, fading, or loss of gloss in high-temperature conditions.

1. Key Performance Indicators and Experimental Data
2. High-Temperature Resistance: The core advantage of high-temperature resistant varnish is its ability to remain stable in high-temperature conditions. Experimental data shows that a certain brand of high-temperature resistant varnish can maintain gloss retention of over 80% after being baked at 180°C for 30 minutes, significantly higher than that of ordinary varnishes under the same conditions.
3. Adhesion: High-temperature resistant varnish exhibits excellent adhesion, forming a tight bond with various substrates. In adhesion tests on paper coated with high-temperature resistant varnish, the results showed an adhesion rating of 4B, indicating a strong and durable bond between the varnish and the paper surface.
4. Hardness: The cured film of high-temperature resistant varnish has a high level of hardness, effectively resisting scratches and wear. Pencil hardness tests revealed that the hardness of a particular high-temperature resistant varnish can reach 3H, far exceeding the 1H hardness of ordinary varnishes, making the printed material surface more resistant to abrasion.
5. Gloss: High-temperature resistant varnish possesses high gloss, enhancing the visual appeal and texture of printed materials. Experimental data indicates that its cured gloss can exceed 85%, significantly improving the aesthetic quality and feel of the product.

1. Application Fields and Case Analysis

High-temperature resistant varnish finds extensive applications in the printing, packaging, automotive parts identification, construction material printing, and various industrial sectors such as electronics, electrical appliances, and aerospace. In the printing industry, it protects paper surfaces, enhances printing effects, and prolongs the service life of printed materials. For instance, in oven labels, the use of high-temperature resistant varnish ensures that labels remain unaffected by heat in ovens, preserving their original color and gloss. In food packaging, it enhances the heat resistance of packaging, preventing damage during production and storage, while also providing moisture protection and safeguarding printed materials from humidity.

1. Precautions for Use
2. Temperature Control: The application temperature for high-temperature resistant varnish is generally between 25°C and 50°C. In winter, when temperatures are low, water bath heating can be used to reduce the viscosity of the varnish, ensuring good flow and coating performance.
3. UV Light Energy: The energy of the UV light should exceed 60 mJ/cm² to ensure complete curing of the varnish. Insufficient energy may lead to incomplete curing, affecting performance.
4. Avoid Direct Sunlight: The UV coating machine should be placed away from direct sunlight to prevent slow curing of the varnish, which could impact work efficiency and quality.
5. Skin Contact: If the varnish accidentally comes into contact with the skin, it should be immediately washed off with soapy water to avoid skin redness and blistering.
6. Viscosity Adjustment: Select varnish with appropriate viscosity based on the type of coating machine, and adjust viscosity with thinners or thickeners if necessary.
7. Specialized Varnish Selection: Choose specialized varnish according to the nature of the substrate, such as gold card paper oil or PET-specific oil, to ensure optimal adhesion and performance.

1. Conclusion

High-temperature resistant varnish, with its unique heat-resistant properties and stable gloss, offers superior protection for printed materials, ensuring they remain vibrant and intact in high-temperature environments. By paying attention to usage details, the performance of the varnish can be fully utilized. Its widespread applications and significant effects make it an indispensable material in the printing industry.