Scratch durability of automotive clear coatings: A quantitative, reliable and robust methodology

Scratch and mar durability of clear coatings are issues of concern to the a uto-mobile manufacturer and paint supplier. Scratching of clearcoats is a c onsequence of tribological events encountered by painted exteriors during n ormal service life. Several subjective methods to assess scratch durability have been proposed. These methods offer little insight into scratch mechan isms. More recently, single scratch methods have been proposed to probe cle arcoat scratch mechanisms. This paper outlines a reliable and robust scratc h methodology for evaluating scratch durability Of automotive clear coating s. It is shown that, with appropriate characterization of tip geometry, qua ntitative and reproducible critical load values can be obtained. A suggeste d test method for scratch durability is described.