The application of paint to polypropylene and thermoplastic polyolefin (TPO) is difficult because of the poor adhesion of most coatings to plastics. Eastman chlorinated polyolefins (CPOs) are widely used as adhesion promoters for coatings and inks on polyolefin plastics such as untreated polyethylene, polypropylene, or TPO. Our chlorinated polyolefins serve as adhesion promoters in at least three ways:
As a primer between the substrate and subsequent coatings
As a primer or tie coat between coatings layers
As an additive to the paint or ink
Formulating with waterborne CPO adhesion promoters
With Eastman CPO dispersions, it is possible to apply an adhesion-promoting primer from a waterborne system or to promote adhesion of a waterborne coating through use as an additive. Eastman CPO dispersions are useful as the base resin in adhesion-promoting primers and as an additive by being added directly to waterborne coating formulations to improve adhesion to polypropylene-based substrates.
Formulating with nonchlorinated adhesion promoters
Eastman also offers nonchlorinated adhesion promoters that provide excellent adhesion to TPO and polypropylene substrates. Eastman adhesion promoter 550-1, supplied at 25% weight solids in either Aromatic 100 or xylene, exhibits excellent gasoline resistance under a variety of polyurethane (2K) and melamine-cured systems. In addition, formulators can now select a waterborne adhesion promoter, Eastman Advantis 510W, that is chlorine free and AEPO free. Used as a blend-in additive for waterborne primers and/or base coats, this product enables the development of VOC-compliant coatings for adhesion of coatings to modified polypropylene substrates.