Plastic coloring products are subject to a variety of factors will fade discoloration of plastic coloring products and pigments, dyes light resistance, oxygen resistance, heat resistance, acid and alkali resistance and the characteristics of the resin used should be based on the processing of plastic products Conditions and requirements of use, in the production of the masterbatch of the required pigments, dyes, surfactants, dispersants, carrier resins and anti-aging additives, a comprehensive assessment of the above properties before use.
1, light-fastness of light-resistant coloring agent
Light fastness The light fastness of colorants directly affects the fading of products. The outdoor products subject to strong light irradiation, the light resistance (lightfastness) grade requirements of colorants used are an important index, and the light fastness grades are poor, and the products will quickly fade during use.
Weathering products selected light level should not be less than six, the best selection of seven, eight, indoor products optional four or five carrier resin light resistance of the color change also has a greater impact, UV-induced resin irradiation Its molecular structure changes appear faded in the masterbatch by adding UV absorbers and other light stabilizers, can improve the colorants and colored plastic products, light resistance.
2, heat-resistant pigment thermal stability
Heat-resistant pigment thermal stability refers to the processing temperature of the pigment under the weight loss, discoloration, fading degree of inorganic pigments of the composition of metal oxides, salts, good thermal stability, high heat resistance while organic compounds 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 ℃, on the one hand to select the toner to focus on pigment heat resistance, on the one hand Consider the heat-resistant pigment time.
3, anti-oxidation
Some of the organic pigments undergo macromolecular degradation or other changes that gradually fade after oxidation, a process of high temperature oxidation during processing, and second, oxidation of strong oxidants such as chromate in chrome yellow. , Azo pigments and chrome yellow mixed use, the red will gradually diminish.
4, acid and alkali coloring plastic products
Acid and alkali colored plastic products fade and chemical resistance of the colorant (acid and alkali resistance, resistance to oxidation reduction), such as molybdenum chromium red acid resistance, but sensitive to alkali, cadmium yellow acid, these two Pigments and phenolic resins play a strong role in the reduction of certain colorants, which severely affect the heat resistance, weatherability and discoloration of the colorants.
For the discoloration of plastic coloring products, the above properties of the required pigments, dyes, surfactants, dispersants, carrier resins and anti-aging additives should be comprehensively evaluated according to the processing conditions and requirements of the plastic products during the production of the masterbatch Only after use.