| abstract |
Powder coating compositions are disclosed. In general, individual powder coating compositions of this invention are a mixture of several materials. The most significant materials employed in the powder coatings include the following. A copolymer containing epoxy and anhydride crosslinkale, functional groups, forms the most important constituent of the powder coating. This copolymer has a glass transition temperature in the range of 40*C to 90*C and a molecular weight (Mn) in the range from about 3,000 to about 10,000. Another material of an individual composition is a flow control agent which forms at least 0.05 percent by weight of the mixture. The flow control agent is a polymer having a molecular weight (Mn) of at least 1000. Also, the flow control agent has a glass transition temperature at least 50*C lower than the glass transition temperature of the copolymer. Other materials which may be employed in individual powder coating compositions are catalysts, pigments, antistatic agents and plasticizers. |