Exterior Durability in All-Acrylic Architectural Gloss Coatings

Maximizing the gloss retention and dirt-pickup resistance (DPUR) is a key requirement for many exterior architectural coatings and is a target that many commercial paints struggle to meet.  In this study, the exterior durability of a range of resins and paints were evaluated.  In particular, for DPUR, an accelerated testing method is compared to exterior exposure data collected from Midwest and West Coast test fence locations.  The location of the exterior exposure is shown to have a large impact on the ability to discriminate DPUR performance between paints/resins in a short period of time.  Paints that have a similar DPUR performance when they are exposed at the Midwest location show much larger differences when they are exposed at the West Coast location in as little as 3-4 months. 

Several accelerated DPUR testing protocols (1 week procedure) are also performed, and while many samples perform relatively similar, some discrepancies are noted.  These results underscore the impact that the exterior exposure location/testing protocol has on DPUR.  In the second part of this study, the gloss retention is evaluated by an accelerated QUVA protocol and compared to exterior exposures.  The accelerated QUVA method can discriminate between formulas in a shorter period of time (4-8 weeks) and tends to agree well with longer-term exposures (> 1 year) from the West Coast.

Presented at the Waterborne Symposium Conference, February 19 - 24, 2017