Plastic coloring products will be affected by a variety of factors fade. The fading of plastic coloring products is related to the light resistance, oxygen resistance, heat resistance, acid and alkali resistance of the color powder and the characteristics of the resin used.

The following is a detailed analysis of the fading factors of plastic coloring:

1. The light fastness of colorant

The light fastness of colorant directly affects the fading of products, outdoor products exposed to strong light, the light fastness (fast) grade requirements of the colorant used is an important indicator, the light fastness grade is poor, and the products will fade quickly in use. The light resistance grade of weather-resistant products should not be less than six levels, it is best to choose seven or eight levels, and indoor products can be selected four or five levels.

The light resistance of the carrier resin also has a great impact on the change of color, and the molecular structure of the resin after irradiation caused by ultraviolet light changes and fades. Adding UV absorbent and other light stabilizers to the masterbatch can improve the light resistance of colorants and colored plastic products.

2. Heat resistance

The thermal stability of heat resistant pigments refers to the degree of thermal weight loss, discoloration and fading of pigments at the processing temperature.

Inorganic pigment components for metal oxides, salts, good thermal stability, high heat resistance. The organic compounds of the pigment at a certain temperature will occur molecular structure changes and a small amount of decomposition. Especially PP, PA, PET products, processing temperature above 280¡æ, in the selection of colorants on the one hand, we should pay attention to the heat resistance of the pigment, on the one hand, we should consider the heat resistance time of the pigment, usually require a heat resistance time of 4-10min.

3. Antioxidant

Some organic pigments in the oxidation after the degradation of macromolecules or other changes and gradually faded, this process is one of high temperature oxidation in the process, the second is the oxidation of strong oxidants (such as chromate in chromic yellow). Color lake, azo pigments and chromium yellow mixed with the use of red will gradually diminish.

4. Acid and alkali

Coloring plastic products fade and colorant chemical resistance (acid and alkali resistance, oxidation reduction resistance) related. Such as molybdenum chromium red resistance to dilute acid, but sensitive to alkali, cadmium yellow is not acid resistant, these two pigments and phenolic resin on some colorants play a strong reduction effect, seriously affecting the heat resistance of colorants, weather resistance and fading.

In view of the fading of plastic coloring products, should be based on the processing conditions and requirements of plastic products, the required pigments, dyes, surfactants, dispersants, carrier resins and anti-aging additives can be selected after a comprehensive evaluation of the above properties.

Plastic Industry Video