We often can discover, plastic productions more or less can appear after long-term deposit fade condition.
So why do plastic productions fade?
Today, YanKang will show you the fading reason of plastic productions scientifically.
Let’s get to know!
The light resistance of colorants directly affects the fading of products.
For outdoor products exposed to strong light, the light resistance (sun resistance) grade requirement of colorants used is an important index.
Poor light resistance, products will quickly fade in use.Weather resistant products should be selected light resistance level should not be less than six, the best choice of seven, eight, indoor products can choose four, five.
The light resistance of the carrier resin also has a great influence on the color change.
On the one hand,adding uv absorber and other light stabilizers to the masterbatch can improve the light resistance of colorants and painted blow molding products.
On the other hand,develop the multi-layers blow molding machine,use the black martical in the middle of layers to resistante the sunny,protect the broken from sunshine.
Coloring blow molding products fade and colorant resistance to chemical properties (acid and alkali resistance, oxidation reduction resistance).
For example, molybdenum chromium red is resistant to dilute acid, but sensitive to alkali, cadmium yellow is not resistant to acid, these two kinds of pigments and phenolic resin have a strong reduction effect on some colorants, which seriously affect the heat resistance, weather resistance and fading of colorants.so need printing on the face of the production to protect sometime
Some organic pigments fade gradually after oxidation due to macromolecular degradation or other changes.
This process is one of the processing of high temperature oxidation, the other is encountered in strong oxidants (such as chromium yellow chromate) oxidation.
Red will gradually fade when the lake, azo pigment and chrome yellow are mixed.
The thermal stability of pigments refers to the degree of thermal weightlessness, discoloration and discoloration of pigments at the processing temperature.
Inorganic pigments are composed of metal oxides and salts, which have good thermal stability and high heat resistance.
However, pigments of organic compounds will undergo molecular structure changes and a small amount of decomposition at a certain temperature.Especially PP, PA, PET products, processing temperature above 280 ℃, when choose stain on the one hand, should pay attention to the heat resistance of paint.To consider the heat resistance time of pigments, the heat resistance time is usually required to be 4-10min.
Do you know why the plastic productions will fade?
To learn more about blow molding machine, please visit blow molding machine blog.