Heat resistance refers to in a certain processing temperature and within a certain period of time, no obvious changes in color light, coloring power and performance.

Plastic coloring and ink and paint coloring the biggest difference is that the vast majority of plastic cooperative color molding has a heating process, colorant in plastic molding often by heat decomposition, color changes, will affect its resistance to light and resistance to migration.So heat resistance in plastic coloring is a very important indicator.

At the beginning of the development of the plastic industry, the processing temperature above 200℃ is rare.But now 300℃ or higher processing temperature, is also very common.The processing temperature ranges of various plastics vary.It makes no sense to require virtually all colorants to be able to resist heat at 300 ° c.The heat resistance of general inorganic pigments is very good, but the heat resistance of organic pigments and dyes is not the same, can maintain stability in the high temperature of organic pigments, the most used are phthalocyanine green, phthalocyanine blue and carbazole purple, quinacridine red and isoindolinone yellow, and the classical azo pigment heat resistance is much lower.Therefore through the heat resistance index to choose the appropriate colorant is particularly important.