White masterbatch performance indicators color, whiteness, yellowness, yellowing, thermal stability and oxygen index, melt flow rate, of course, the fineness of the pigment, migration resistance, chemical resistance, and toxicity masterbatch For granular properties, some indicators are important in specialized applications, such as pressure filtration stage median fiber masterbatch (DF value) fineness.
1. The light resistance of lightfast colorants directly affects the fading of products. For outdoor products exposed to strong light, the lightfastness (lightfastness) rating of the colorants used is an important indicator. The lightfastness is poor and the products are used very quickly. fade. Weathering products selected light level should not be less than six, the best selection of seven or eight, indoor products optional four, five. Light fastness carrier resin has a greater influence on the color change, after the resin molecular structure which is irradiated with ultraviolet light induced changes faded. By adding a light stabilizer such as a UV absorber to the master batch, the light resistance of the colorant and the colored plastic article can be improved.
2. The thermal stability of a heat-resistant pigment refers to the degree of heat loss, discoloration, and fading of the pigment at the processing temperature. The inorganic pigment is composed of metal oxides and salts, has good thermal stability and high heat resistance. However, the pigment of an organic compound undergoes a change in molecular structure and a small amount of decomposition at a certain temperature. Especially for PP, PA, PET products, the processing temperature is above 280 °C. On the one hand, when selecting the coloring agent, attention should be paid to the heat resistance of the pigment. On the one hand, the heat resistance time of the pigment should be considered, and the heat resistance time is usually required to be 4-10rain. Hey.
Some metal ions in the pigment promote the thermal decomposition of the resin. Among them, pigments containing copper, manganese, iron and cobalt have a strong effect on promoting the aging of polyolefins, while pigments containing potassium, sodium, cadmium and calcium are less affected. . The same metal elements are enhanced in the order of pure metals, metal oxides, and metal salts.
3. Oxidation resistance Some organic pigments gradually degrade after macromolecular degradation or other changes after oxidation. The first process is high temperature oxidation during processing, and the second is the occurrence of strong oxidants (such as chromate in chrome yellow). Oxidation. When the lake, azo pigment and chrome yellow are mixed, the red color will gradually decrease.
4. The fading of acid and alkali resistant colored plastic products is related to the chemical resistance (acid and alkali resistance, oxidation and reduction resistance) of colorants. For example, molybdenum chrome red is resistant to dilute acid, but sensitive to alkali, and cadmium yellow is not resistant to acid. These two pigments and phenolic resin have strong reduction effect on certain colorants, which seriously affect the heat resistance, weather resistance and fading of the colorant.