20.500.12556/DKUM-71139 Analiza in optimizacija pigmentnih past za kovinske premaze na vodni osnovi Analysis and optimisation of pigment pastes for waterborne industrial coatings Diplomsko delo prikazuje pregled sistema 16 vodnih past, kjer je bila na podlagi rezultatov izbrana ena pasta na kateri smo opravljali dodatne analize in poiskali smernice, za kasnejšo optimizacijo celotnega sistema. Za pregled sistema smo opravili test obriba (angl. rub–out test) na dveh različnih osnovah (Os I (osnova na osnovi stiren akrilne disperzije) in Os II (osnova na osnovi poliuretanske smole)) ter izmerili razliko v barvnem odtenku (DE*) in barvni jakost (BJ). Sledile so reološke analize, kjer smo izmerili viskoznost sistema in ugotavljali ali imajo paste ustrezno tiksotropijo (razmerje med začetno in končno viskoznostjo), pregledali smo kako so paste obstojne po naravnem staranju in naredili standardne kontrolne metode (meritve pH vrednosti in gostote). Reologija past je bila izmerjena na začetku dela in naslednjič po naravnem staranju past. Pri nekaterih pastah so se opazile spremembe v viskoznosti po staranju, kar jasno nakazuje na njihovo nestabilnost. Eno izmed najbolj nestabilnih disperzij je prikazovala pasta 06, katero smo kasneje tudi izbrali za optimizacijo. Na vseh pastah smo naredili test obriba z neredčenim in redčenim kolorantom, pri čemer so se pokazale vidne razlike v barvnih odtenkih pri redčenem kolorantu, kar je ponoven indikator za nestabilnost disperzij, saj pigmenti med sušenjem premaza še vedno migrirajo. Vizualno se večina past po naravnem staranju ni spremenila. Optimizirali smo pasto 06, pri čemer smo spreminjali parametre, pri katerih je pasta nastajala, ter količino dodanega omakala. Z analizami smo ugotovili, da na finost mletja primarno vpliva čas mletja paste, opazen je tudi manjši vpliv temperature in omakala. Previsoka ali prenizka temperatura finost mletja poslabšata, podoben trend se opazi tudi s količino omakala. Parametri zelo podobno vplivajo na barvno jakost, ki se z dolžino mletja povečuje zaradi večje specifične površine delcev. Test obriba je večinoma odvisen le od časa mletja ter posledično končne velikosti delcev, ki pasto sestavljajo. Podoben trend, kot je viden pri testu obriba, je opazen tudi pri spektrofotometrični analizi odtenkov past. Na koncu smo s pomočjo metode simpleks ugotovili, kateri so optimalni pogoji za izdelavo te specifične paste. Prišli smo do ustrezne barvne jakosti, do ustrezne finosti mletja, do dovolj majhne razlike v odtenkih ter do najboljšega rezultata za test obriba. In this diploma paper an overview of 16 waterborne pigment pastes has been made. Later, one of them has been selected and additionally analysed according to the results. Also some further guidelines for the system optimization have been given. During the system review we tested two different resins (I and II) with the rub-out test, and evaluated the difference in the colour nuance (DE *) and the colour strength (BJ). Rheology analysis has been done to examine the viscosity of the system and its thixotropic behaviour. We have also examined the durability of the pigment pastes after their natural aging and derived standard control method, such as pH value and density of the pigments. Rheology of the pigment pastes has been done at the beginning and after their natural aging. We noticed some differences in viscosity of the pigment pastes which lead us to conclusion that the structure of the pigment pastes is not stable. The pigment paste 06 has shown the greatest emulsion decomposition. Thus, it was chosen for some additional analysis and optimization. All the pigment pastes have been put to a rub-out test with diluted and undiluted colorants. Some highly visible changes in nuances were shown with diluted colorant, which again lead us to conclude that the structure of the pigment pastes is not stable because the pigments still migrate while the coating is drying. Most of the pigment pastes have visually remained the same after their natural aging. During the optimization of the pigment paste 06 we have changed the quantity of the wetting agent and the parameters by which the paste has been made. The analysis proves that the finesse of the grinding is mainly affected by the time of grinding, and partly by temperature and the wetting agent. Too high or too low temperature negatively affects fineness of the grind. Similar results were concluded when quantity of the wetting agent changed. The parameters affect colour strength in a similar way, which increases parallely to the time spent grinding due to bigger specific surface area of the particles. The rub-out test mainly depends on the grinding time and final particle size which compose the paste. It is similar in the case of the spectrophotometric analysis of the paste nuance. At the end we have reached optimal conditions to produce the specific pigment paste by using the Simplex method. We have achieved the proper colour strength, appropriate grind fineness, small difference between the colour shades and obtained the best possible results of the rub-out test. paste na vodni osnovi koloristika reologija test obriba metoda simpleks waterborne pigment pastes colour technology flow test rub – out test Simplex method true true false [T. Drobnič] Slovenski jezik Angleški jezik Diplomsko delo/naloga 2018-07-21 18:03:41 2018-09-11 15:10:36 2022-08-01 20:25:09 2019-07-11 18:31:39 2018 0 Maribor 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 532.135:667.633.42(043.2) 21952534 URN:SI:UM:DK:02H5MJZK UN_Drobnic_Tea_2018.pdf UN_Drobnic_Tea_2018.pdf 1 46FDDE360513ABC67F8C7FE5571627AF 913fabaaa393e12e260fa377566a211e81b399dee24bd72a52a9282c3cd32884 4548eb62-7c10-11eb-bb7a-00155d0001ca 20.500.12556/dkum/44edc4f3-3f04-4bd4-81bd-c684eab2b3d3 https://dk.um.si/Dokument.php?lang=slv&id=128878 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0