A unique primer emulsion chemistry yields excellent adhesion of polyethylene terephthalate (PET)resin to clay coated paperboard (with high starch content)at reduced coatweights of the primer emulsion and the resin as compared to other primer and tie-resin chemistries currently employed for moisture barrier applications. A primer used for adhesion enhancement is an ammonium catalyzed, self-crosslinking copolymer of ethylene-vinyl acetate with N-methylol acryl amide functional groups attached to a polymer backbone. Use of the primer in amounts up to about 0.5 pounds per ream permits PET coatweights of as low as 10 12 lbs per ream and lower for some applications.