I believe that many people are very worried about the fading of the plastic EVA toolkit. So what causes the fading of the toolkit? The fading of plastic colored products is related to the light resistance, oxygen resistance, heat resistance, acid and alkali resistance of the pigments and dyes, and the characteristics of the resin used. Let's analyze it briefly below.

1. The fading of acid and alkali resistant colored plastic products is related to the chemical resistance of the colorant (acid and alkali resistance, oxidation-reduction resistance).

For example, molybdenum chrome red is resistant to dilute acid, but is sensitive to alkali, and cadmium yellow is not acid resistant. These two pigments and phenolic resin have a strong reducing effect on some colorants, which seriously affect the heat resistance and weather resistance, leads to fade.

2. Anti-oxidation Some organic pigments undergo macromolecular degradation or other changes after oxidation and gradually fade.

This process is one of high temperature oxidation during processing, and the other is oxidation when encountering strong oxidants (such as chromate in chrome yellow). After the lake, azo pigment and chrome yellow are mixed, the red color will gradually fade.

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

Inorganic pigments are composed of metal oxides and salts, with good thermal stability and high heat resistance. The pigments of organic compounds will undergo molecular structure changes and a small amount of decomposition at a certain temperature. Especially for PP, PA, PET products, the processing temperature is above 280℃. When selecting colorants, we should not only pay attention to the heat resistance of the pigment, but also consider the heat resisting time. The heat resisting time is usually 4-10 minutes.

4. The light resistance of colorants directly affects the fading of products.

For outdoor products irradiated by strong light, the light resistance level of the colorant used is an important index. If the light resistance level is poor, the product will quickly fade during using it. The light resistance grade of weather-resistant products should not be lower than six grades, preferably seven or eight grades, and four or five grades for indoor products.

The light resistance of the carrier resin also has a great influence on the color change. After the resin is irradiated by ultraviolet rays, its molecular structure changes and fades. Adding light stabilizers such as ultraviolet absorbers to the masterbatch can improve the light resistance of colorants and colored plastic products.