Colored plastic products can lose their color due to various factors. The fading of these products is influenced by the lightfastness of the pigment, dye, oxidative stability, heat resistance, acid and alkali resistance, and the characteristics of the resin used. Depending on the processing conditions and usage requirements of plastic products, a comprehensive evaluation of the aforementioned properties of the desired pigments, dyes, surfactants, dispersants, carrier resins, and anti-aging additives should be conducted prior to producing the masterbatch.
1. The lightfastness of lightfast colorants plays a direct role in the fading of products. For outdoor products exposed to intense sunlight, the lightfastness (lightfastness) rating of the colorants used is a crucial factor. If the lightfastness is poor, the product will fade rapidly. Weather-resistant products should have a lightfastness grade of no less than six, preferably seven or eight, while indoor products can have a lightfastness grade of four or five. The lightfastness of the carrier resin also significantly impacts color changes, as ultraviolet radiation alters the molecular structure of the resin, leading to fading. Adding a light stabilizer like a UV absorber to the masterbatch can enhance the lightfastness of the colorant and the colored plastic product.
2. The thermal stability of heat-resistant pigments refers to how much they lose color, change hue, or fade at processing temperatures. Inorganic pigments, made up of metal oxides and salts, possess excellent thermal stability and high heat resistance. However, organic pigments undergo molecular changes and slight decomposition at certain temperatures. This is particularly noticeable for PP, PA, and PET products, where the processing temperature exceeds 280°C. When choosing a coloring agent, both the heat resistance of the pigment and its heat resistance time must be considered. Typically, a heat resistance time of 4 to 10 minutes is required. Some metal ions in pigments promote the thermal decomposition of the resin. Pigments containing copper, manganese, iron, and cobalt strongly promote the aging of polyolefins, whereas 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 degrade over time through macromolecular degradation or other changes caused by oxidation. The first process occurs during high-temperature oxidation in processing, and the second involves the presence of strong oxidants, such as those found in chrome yellow. When lake pigments, azo pigments, and chrome yellow are mixed, the red color will gradually diminish.
4. The fading of acid and alkali resistant colored plastic products is linked to the chemical resistance (acid and alkali resistance, oxidation and reduction resistance) of colorants. For instance, molybdenum chrome red is resistant to dilute acids but sensitive to alkalis, while cadmium yellow is not acid resistant. These two pigments, along with phenolic resin, have a strong reducing effect on some colorants, significantly impacting the heat resistance, weather resistance, and fading of the colorants.
In conclusion, understanding these factors is essential for ensuring the longevity and vibrancy of colored plastic products. By carefully selecting the right pigments and additives, manufacturers can minimize fading and maintain product quality over time.
Dress Mesh Clothes,Sexy Suspender Skirt Sexy Lingerie,Sexy Lingerie,Lace Lingerie Suspender Sets
Lianyungang Continuation Qianyuan International Trade Co., Ltd. , https://www.zxunderwear.com