| abstract |
The present invention provides a powder composition in multiple separate parts comprising one or more than one resinous powder component in one or more than one part and, for each resin component, one or more than one powder, liquid or gaseous curing agent component in one or more than one separate part, wherein the average particle size ratio of each resinous powder component to its curing agent powder or droplet component ranges from 1.3:1 to 60:1 to insure the attraction of the resin and its curing agent to one another. Useful resins may include epoxy resin, polyester resin or their combination. The shelf life of the powder composition can be extended indefinitely by storing each resin and its curing agent in separate parts. However, each resin and its curing agent react within a period of from 0.01 to 600 seconds to form a cured powder coating when combined at a temperature of from 20° C. and 200° C. to enable very low temperature cure. In addition, the present invention provides a method of forming a powder coating from the inventive composition which comprises combining each of the separate parts in stream while or by applying them to a substrate, for example, as two or more than two separate feed streams from a single applicator device, followed by curing. |