Several main factors affecting the fading of plastic woven bags

Plastic woven bags in the process of use more or less will occur some fading phenomenon, the occurrence of this phenomenon is actually with the pigment, dye light resistance, acid and alkaline resistance, heat resistance, antioxidant and the characteristics of the resin has a certain relationship. Here is a detailed analysis of the reasons:

1. Thermal stability of heat-resistant pigments refers to the degree of weight loss, discoloration and fading caused by pigment heat at the processing temperature. The main components of inorganic pigments are metal oxides and salts with good thermal stability and high heat resistance. Organic pigments, on the other hand, undergo molecular structure changes and a small amount of decomposition at a certain temperature. Especially PP, PA, PET packaging products, its processing temperature is generally above 280℃, in the selection of colorant must pay attention to the heat resistance of the pigment and heat resistance time.

2. The light resistance of pigments will also directly affect the fading of plastic woven bags. The pigment with poor light resistance will fade faster in the process of using the woven bag. The light resistance of carrier resin also has a great influence on the change of color. After uv irradiation, the molecular structure of the resin changes and fades. Adding uv absorbent and other light stabilizers into the base material can improve the light resistance of colorant and fertilizer woven bags.

3. The fading of the woven bag is related to the chemical resistance of the colorant. For example, molybdenum-chromium 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 a strong reduction effect on some colorants, seriously affecting the heat resistance and weather resistance of colorants and causing discoloration.

4. Some organic pigments gradually fade after oxidation due to the degradation of macromolecules or other changes. This process is caused by high-temperature oxidation during processing and oxidation due to strong oxidants.


Post time: Aug-20-2020
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