to cling to metal surfaces which in turn substantially lessens the likelihood that agglomerates will form the net result is that by reducing the tendency to form agglomerates a lesser quantity of magnesium oxide is required to accomplish a particular result than is mandated by prior art processes such as that taught in u s pat no 3 891 598 in addition the requirements for a special screening step to remove agglomerates having a size larger than about 500 microns and for special equipment to add the magnesium oxide powder to the vinylidene chloride copolymer formulation are eliminated the preferred process for blending the normally crystalline vinylidene chloride polymer particles with the magnesium oxide powder and the ethylene vinylalkanoate copolymer dispersing agent described herein comprises a forming an admixture of the magnesium oxide and the ethylene vinylalkanoate copolymer dispersing agent by i physically mixing from about 1 to about 50 percent by weight based on weight of the admixture of the magnesium oxide powder and from about 99 to about 50 percent by weight based on weight of the admixture of the ethylene vinyl alkanoate copolymer ii admixing the physically mixed magnesium oxide powder and ethylene vinylalkanoate copolymer with a high shear mixing means while the ethylene.