Title Poliaspartiniai dažai metalinių ir medinių paviršių dangoms /
Translation of Title Polyaspartic paints for metal and wood coatings.
Authors Navickas, Giedrius
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Abstract [eng] One of the best options to protect any metal or wooden surface from the environment impact is paint. Polyaspartic paints are two-component, with excellent resistance to mechanical and chemical effects, UV rays, can be both glossy and semi-glossy, fast drying and have excellent stability. Polyaspartic paints are widely used in the metal industry for protection of wind turbines, oil and gas pipelines, cars, bridges and various metal structures. However, as wood coatings, polyaspartic paints are not yet commercially used. The aim of the work was to create anti-corrosion polyaspartic coatings with a low content of volatile organic compounds (VOCs) and polyaspartic wood coatings without VOCs. Anti-corrosion coatings contain higher amount of polyaspartic acid esters than wood coatings. In the development of wood coatings, although they are labeled as "VOC-free", a minimal amount of "green" solvents was used. Wood coatings should be more elastic, matte and soft, as well as sufficiently permeable to water so that the moisture in the wood can escape. Anti-corrosion coatings, on the contrary, must be as least permeable to water as possible, so they should be more cross-linked. In addition, anti-corrosion coatings should be resistant to the effects of chemicals and have high hardness and sufficient elasticity. Defects in polyaspartic wood coatings are caused by moisture and relatively large amounts of the "green" solvent propylene carbonate (PC) and polyaspartic reactive thinner (PRS). It was determined, that in order to avoid defects, it is necessary to replace part of PRS with unshielded polyaspartic acid ester (NARE). Paints containing larger amount of NARE and low amount of PRS can be used on wet wood but the amount of PC must not exceed 1.5 % of the part A, and other paint components must contain little moisture. Polyaspartic wood paints of high quality were obtained by adding 5% of monofunctional epoxy reactive thinner to part A: the working life of the paints increased more than 2 times, the elasticity and impact resistance of the coatings increased significantly, and it became possible to obtain semi-matte coatings. The stability of polyaspartic anti-corrosion paints with low VOC content was increased by combining hydrogenated castor oil with another rheological additive, modified urea. Resulting coatings were characterized by high gloss and good mechanical properties. Pigmentation significantly (up to one and a half times) reduces working life of the polyaspartic paints, thus working life of unpigmented paints must be long. Chemical resistance of anti-corrosion polyaspartic coatings has been improved by eliminating reactive fillers, reducing amount of hydrophilic additives and introducing hydrophobic additives to the A part of the paint. The resistance of the polyaspartic coatings to corrosion and UV radiation was improved by adding hydrophobic additives, reducing the amount of aspartic acid esters and replacing part of PRS with the shielded aspartic acid ester.
Dissertation Institution Vilniaus universitetas.
Type Master thesis
Language Lithuanian
Publication date 2024