Paint coatings weathering test results

Specification for electroplated coatings of 65/35 tin/nickel alloy Method for the evaluation of results of accelerated corrosion tests on metallic coatings Methods of test for paints Cross-cut test Pull-off test for adhesion Resistance to artificial weathering (enclosed carbon arc) and Addendum No. 1 Resistance to continuous salt spray Notes for guidance on the conduct of natural weathering test... 

Figure 20-3 shows the results of the accelerated weathering tests on our inorganic coating material and other organic paints. Luster retention rate is defined as follows ... 

ThermoWood is not resistant to exterior weathering and the colour will gradually change to the grey that is characteristic of outdoor exposed wood. In addition, exposure in exterior conditions results in the formation of small cracks on the surface of uncoated wood. Unpigmented or low-build stain coatings do not protect the surface of the wood, but solvent-borne alkyds and water-borne acrylic paints have been found to exhibit better performance than on unmodified wood. VOC emissions from the heat-treated wood are lower compared to unmodified wood and the compositions of the emissions differ. The level of emissions is lower when the wood is treated at a higher temperature. Emissions of terpenes are reduced to very low levels, and the VOC content is dominated by furfural, hexanal and acetic acid (treated at 180 °C), and by acetic acid (treated at 230 °C). ThermoWood passes ecotoxicity tests. 

The relative mildew growth on polymer and on paint samples exposed to Aurobasldlum pullulans was also studied using the "Zabel Test." In this procedure, veneer strips of southern yellow pine and bass wood are sterilized, cooled, and painted (2 coats with 24 hrs. drying time). After 2-3 days the strips were soaked In distilled water, sterilized at 100 C and placed vertically In 16-ounce French square bottles containing 20 gm. of vermiculite. A mlcronutrlent enriched nutrient media was then poured Into the vermiculite (100 ml per bottle). After sterilization at 121 the painted strips were positioned so that the bottom of the painted zone was 0.5 cm above the vermiculite surface. The specimens were Inoculated with a spore suspension of Aureobasldlum pullulans (16624) by pipette. Incubated two months at 28 , and then rated visually with a 20x binocular. In the weathered series, the specimens were exposed four days In an Atlas Weather 0 Meter (UV and water spray). Representative results are summarized In Table 13. 

---