Primers and adhesion promoters are applied to a substrate to enhance the bond strength between a surface coating (e.g., clear coats, adhesives) and the substrate. They differ in terms of type and chemistry, substrate compatibility, technology, application method, color, and finish. Primers and adhesion promoters are used in a variety of industrial and commercial applications, and in many different industries. They are applied to ceilings, decks, floors, roofs, pavement, walkways, and walls. Processing characteristics include coverage, cure or dry time, curing or drying temperature, use temperature, and pot-life time.
Chemistry and Substrate
Primers and adhesion promoters differ widely in terms of chemistry and substrate. Choices for chemistry include acrylic, alkyd, aluminum, cobalt, boron nitride, cement, ceramic, copper, epoxy, glass, graphite, metal and nylon. Also available are primers and adhesion promoters with chemistries such as polyurethane, silicone, silver, stainless steel, vinyl, wax and zinc. There are also many choices for substrate. Examples include aluminum, asphalt, bitumen or coal tar, concrete or masonry, fiberglass, food, glass, graphite, metal, paper, rubber, steel and wood.
Technology is an important specification to consider when selecting primers and adhesion promoters. Film drying or air setting forms a continuous, dry film from a binder that can be pigmented. The evaporation of the solvent, carrier, or thinner sets the coating. Laser marking uses a laser beam to fuse the coating, ink, or marking material with the substrate’s surface. Multi-component coating systems and adhesion promoters use a polymeric protective film that applies a primer or prime coat, intermediate coat, and/or finish coat. Reactive or moisture-cured, thermoplastic, thermosetting and ultraviolet (UV) irradiating products are available.
Primers and adhesion promoters are available as aerosols, cartridges, films, liquids, markers, pastes, powders, and solids. Solvent-based primers primarily use volatile organic compounds (VOCs) as the carrier. Water-based primers and adhesion promoters use water as the primary carrier, but may also contain chemicals such as glycol ethers, alcohols, and other water-soluble VOCs. In terms of application method, primers and adhesion promoters may be applied with autophoretic processes, brushes, curtains, dip or immersion techniques, electrostatic methods, electrocoating, rollers, screens, spins or sprays. Colors vary widely and finishes include flat, satin, semi-gloss and high-gloss.