Joe Zhou + Jeanette Eastman

Abstract

Over many years of research efforts within the automotive coating industry, chemical resistance and scratch resistance remain at the top of the list of desired improvements. Increased environmental pressure to reduce VOC and increase coating solids has forced formulators to adopt the use of low molecular weight polymers which, in general, adversely impact these properties.

To address these unmet needs, Eastman Chemical Company and Covestro LLC have been working together, combining the strengths of both companies to develop a higher performance resin-crosslinker solution for the automotive market. This work examines the performance of 2K polyurethane automotive OEM clearcoats formulated with Eastman polyester resins containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD) and a silane-modified polyisocyanate crosslinker from Covestro.

Five 2K clearcoat resins were evaluated: three TMCD polyester resins, one control acrylic resin and one control polyester resin. Each of these clearcoat resins were crosslinked with either the silane-modified polyisocyanate or a conventional HDI trimer and evaluated for car wash gloss retention, gloss retention after steel wool, crockmeter scratch and chemical resistance by gradient oven.

Use of the silane-modified polyisocyanate as crosslinker in 2K automotive OEM clearcoat formulations is demonstrated to be very effective in improving carwash gloss retention, while TMCD polyester resins provide superior chemical resistance compared to acrylics and conventional polyesters. Together, TMCD polyester resins and the silane-modified polyisocyanate crosslinker enable low-VOC, high performance automotive OEM 2K clearcoats with a superior balance of carwash gloss retention and chemical resistance.

Biography – Joe Zhou

Dr. Zhou is a Senior Research Associate in the Specialty Coatings Technology division of Eastman Chemical Company Since 2005. He has been working in the resin synthesis and coatings formulation area through his entire career. Prior to joint Eastman, Dr. Zhou worked for several paint company including Nippon Paint for many years. Dr. Zhou received his BS in Chemical Engineering from Tianjin University and PhD in material Science from Yokohama National University.

Biography – Jeanette Eastman

Jeanette Eastman has worked at Covestro since 2004. After starting her career in the Powder Coatings group, she has taken on roles with increasing responsibility in other areas, including Construction Coatings. Her work has covered several application areas, including industrial and residential floor coatings, graffiti-resistant coatings and soft touch coatings for automotive interiors. She has experience with two-component solventborne and waterborne polyurethane technologies, as well as one-component polyurethane dispersions, with expertise in both formulation and application. In her current position as chemist in the Automotive Refinish group, she is responsible for all new technical development projects ranging from primer surfacer to clearcoats both waterborne and solventborne, along with aftermarket applications such as peelable coatings.