this invention is based on surprising results that dry - coat particles using a melt process where the dispersed melted polymer core can bead up effectively in a surrounding hydrophobic powder . one good coating powder is identified as organoclay . silica coating also works well when combined with clay coating . with the coating provided , this invention enables generation of a stable powder with , for example approximately 20 %, haip loading using a simple grinding and sieving process . the formulations provided can release less than 25 % 1 - mcp over a period of 4 hours under stirring conditions .