Introduction of heat resistance of plastic pigments in coloring

The heat resistance of plastic pigments refers to the absence of obvious changes in color light, color strength and performance under temperature and time.

The biggest difference between plastic pigment coloring and ink pigment and paint pigment coloring is that most plastic coloring molding has a heating process. Colorants are often decomposed by heat during plastic molding, and the color changes, which will also affect its light resistance and Migration. Therefore, heat resistance is a very important indicator in plastic coloring.

At present, many colorant suppliers test the heat resistance of each pigment in different varieties of plastic pigments according to the EU standard EN BS12877-2 to provide customers with reference. The method stipulates: using 200 degrees Celsius as the benchmark, use the injection machine to inject a standard color plate of a certain concentration of colorant, and then increase the temperature by 20 degrees Celsius every time interval, and leave the color plate after injection for a dwell time of 5 minutes. When the two color plates △E= The temperature at 3 is taken as the heat resistance of the colorant at this concentration.

Pigment heat resistance Z is mainly to change the chemical structure of the pigment. The usual methods are: increasing the molecular weight of the pigment; introducing halogen atoms into the molecule; introducing a substituent group into the fused ring structure molecule; introducing metal atoms.