CURABLE FILM-FORMING COMPOSITION EXHIBITING IMPROVED IMPACT STRENGTH AND CHIP RESISTANCE

摘要

A curable film-forming composition is provided comprising in a medium (i) 10 to 90 percent by weight based on the total weight of solids in the film-forming composition of a crosslinking agent; (ii) 10 to 90 percent by weight based on the total weight of solids in the film-forming composition of a polymer containing a plurality of functional groups reactive with the crosslinking agent; and (iii) at least 20 percent by volume based on the total volume of the film-forming composition of particles having a mean particle size less than 100 nm. A cured composition comprising the crosslinking agent of (i) and the polymer of (ii) has a cured softening point of less than 30°C. The particles of component (iii) further have a hardness value greater than 5 on the Moh hardness scale, and have an affinity for the medium sufficient to keep the particles suspended therein. The affinity of the particles for the medium is greater than the affinity of the particles for each other, thereby preventing agglomeration of the particles within the medium. Cured compositions having a film thickness of at least 5 microns demonstrate excellent chip resistance, superior sandability and resistance to scratching, water spotting and acid etch.