Reasons For The Color Of Plastic Preforms

The preform is the embryo before the bottle is formed. The tube wall is thick and clear, and can be sealed with ordinary plastic caps. Also, it cannot break off and stand on the table. It can replace test tubes in many ways.​​

The light resistance of colorants for plastic preforms directly affects the fading of products. For field products exposed to strong light, the lightfastness rating of the colorant used is an important goal. Due to poor light fastness, the product will fade quickly in use. That's why, for example, anti-glare sheets and water horses on highways can fade after years of exposure to sunlight, but generally, blow-molding processes add quantitative UV-blocking ingredients to ensure that the product retains its color when durability. Inorganic pigments are composed of metal oxides and salts and have good thermal stability and heat resistance. Pigments in organic compounds change their molecular structure and cause a small amount of decomposition at the corresponding temperature.​​

In fact, in the process of producing plastic preforms, if it is a plastic product that requires high temperature heating, a pigment with strong heat resistance should be selected to ensure the discoloration, fading and overall appearance of the product. Some organic pigments gradually fade after oxidation due to macromolecular degradation or other changes. One is high temperature oxidation during processing, and the other is oxidation in the presence of strong oxidizing agents such as chromates in chrome yellow. When the lake, azo pigments and chrome yellow are mixed, the redness gradually decreases.​​

The fading of colored plastic products is related to the chemical resistance, acid and alkali resistance and redox resistance of colorants. For example, molybdenum-chromium red is resistant to dilute acid, but sensitive to alkali, and cadmium yellow is not acid-resistant. These two pigments and phenolic resins have a strong reducing effect on some colorants, which seriously affect the heat resistance, weather resistance and fading properties of the colorants.​​

Well, I will share with you the reasons for the color loss of plastic preforms here. If you have any questions, you can consult us.