The optical brightener is an important plastics additives. It plays an important role in enhancing the appearance of the product grade. Then how to choose suitable optical brighteners is a meaningful topic to study.
1, High-temperature resistance of the optical brightener
Plastic products molding temperature is relatively high, usually can reach 200 ℃ or more. some engineering plastics molding temperature even reached 300 ℃ or more. Those high-temperature plastics require an optical brightener that can resist high temperatures to maintain good stability. The following are several commonly used plastic brighteners melting points. The melting point refers to the brightener powder heat from solid to liquid temperature. The higher the melting point of the brightener, the better the high-temperature performance.
2, weather resistance of the optical brightener
Many outdoor plastic products, such as outdoor billboards, are placed outdoors for a long time. In order to avoid long-term sunlight fading and yellowing of the product, we need to choose optical brighteners with very good weather resistance. Weather resistance refers to the aging of plastic products after sunlight, temperature changes, wind and rain, and other external conditions, and a series of aging conditions such as discoloration, fading, chalking, and strength reduction.
3,Immigration resistance of the optical brightener
The optical brightener will be partially dissolved in the plastic at a certain processing temperature. Therefore it should have a good immigration resistance. For example, the OB-1 has the feature of good initial coloring and whiteness. But in plastic resin, if the dosage of OB-1 exceeds 0.02%, it might separate out and the plastics will look yellowish. Therefore we should pay attention to the dosage of optical brighteners for plastic, especially soft plastics.