subject: Polymer Colorant - Learning Some Basic Facts [print this page] Plastic is undoubtedly one of the most important inventions of human history, which has become an integral part of our everyday lives. The term plastic is generally used for a wide range of synthetic or semi-synthetic products created as a result of polymerization and having the basic property of plasticity. However, most often plastics contain other substances or additives which help in enhancing some of their basic properties such as their stiffness, strength, resistance to heat and flame or even resistance to electricity. Polymer colorant is one of the several additives used and serves the specific purpose of imparting color to plastics.
The colorants used with plastics are primarily of two types, namely organic colorants also known as dyes and inorganic colorants also known as pigments. Generally, the choice of the type of polymer colorant that would be most suitable for the plastic depends on the amount of light that the plastic is exposed to and the service temperature of the plastic. Since pigments show a greater resistance to both temperature and light they are used for dying plastics that are more likely to be used in high temperature areas where they are also constantly exposed to light. Other important factors that need to be considered during the choice of a colorant for plastics are their applications, level of colorfastness and reaction to base plastic material.
Today, through the use of a proper combination of polymer colorant system, it is possible to add special effects to the appearance of plastic. That is why it is now possible to find plastic that have a metallic, pearlescent, stone and fleck and even thermo-chromatic and photo-chromatic appearance. It is also vital to use the right colorant system to ensure greater efficiency of the plastic end product. For example using colorant systems that provide little or no X-ray opacity for plastics intended to be used in medical applications, can render the end products useless for such purposes. As such it is vital to pre-determine the end use of the plastic prior to choosing the most suitable coloring option for it. Similarly, in plastics that are used for manufacturing toys or items for household use, the brightness and safety takes prominence over other factors.
