SEDL / STP / STP781-EB / STP33761S

Accelerated Outdoor Weathering Tests for Evaluating the Durability of Coatings

Morse, MP
Research associate, E. I. du Pont de Nemours & Co., Inc., Marshall R & D Laboratory, Philadelphia, Pa.

Pages: 24    Published: Jan 1982

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Abstract

Specialized outdoor exposure racks have been evaluated to determine their utility in providing useful predictions of weathering durability. The specialized racks studied were the (1) seasonally adjusted angle, open-back rack, (2) black box, (3) heated black box, (4) reflector black box, and (5) Fresnel reflector rack (EMMAQUA). The geographical locations used in the study were Florida, Puerto Rico, and Arizona. The rankings of automotive and coil coatings for gloss loss and color change produced by each of the exposure techniques have been compared for correlation and the acceleration of degradation. No appreciable acceleration of coating degradation was produced by the use of seasonally adjusted angle settings of exposure racks. The other exposure techniques provided significant accelerations of the degradation of some types of coatings. The usefulness and limitations of each technique for predicting coating durability are discussed.