The Key Properties And Formula Research Of The Waterborne Coatings For Outdoor Wooden Frames

With the increasingly serious environmental protection, energy-saving of the buildingmaterials is becoming more and more important. Wood aluminum composite window is anew kind of window, accounts for5~10%in the domestic market. It can insulate heat andnoise, and is more cost-effective than traditional aluminous window or pure wood window.The wood part of wood aluminum composite window is located indoors, which can beapplied with solventborne coatings and waterborne coatings, the latter accounts for50-70%.These paints need to keep quality in more than2years as the windows are always inhalf-outdoor location, which would last to5-10years if there are conservation measures.Therefore coatings should have water-resistance, UV resistance, anti-temperature change,anti-fungus, and flexibility. It’s necessary to separate window coatings’ formula andstandards from the indoor coatings’as the requirement is apparently different.Currently there is no national standard or industry standard for outdoor water-basedwood coatings. In the formulation development, engineers always reference to internationalstandards, or personal experience. In this paper, domestic and foreign standards for outdoorwater-based wood coatings are synthetically analyzed, including the performance standardsand the pests evaluation standards. This analysis would be helpful for formulationdevelopment and product evaluation.This paper described the factors which affected the durability of the outdoorwater-based wood coatings, including the wood and processing, paint and film thickness,environment and so on. It was found that to ensure good durability, the thickness of each wetfilm should be more than125microns, while the accumulated thickness should be more than250microns.This paper analyzed the key performance of the outdoor water-based coatings, and theselection basis of resins and additives. The resins and anti-fungal agents are analyzed byartificial weathering test, real weathering test, and agar method. The experimental resultsshow that using resins A, adding0.7%IPBC class fungicide, and compounded0.2%triazole fungicide as a primer, then using resins D, adding0.3%UV absorber and0.5%IPBC classfungicide as a topcoat, can achieve the optimum overall performance.