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Abstract(s)
O principal objetivo deste trabalho consistiu no desenvolvimento de um esmalte aquoso direto à ferrugem. Pretendia-se um produto que convertesse a ferrugem pré-existente, fornecesse uma boa proteção anticorrosiva a longo prazo e que inibisse a ferrugem instantânea. Para efeitos de comparação, analisaram-se três produtos comercializados, dois esmaltes de base aquosa da concorrência e o esmalte de base solvente da Fábrica de Tintas 2000. O trabalho dividiu-se em duas partes: o estudo da influência de diferentes matérias-primas nos ensaios realizados, o que permitiu reajustar a formulação até obter o melhor ensaio, e a análise dos ensaios que se encontravam de acordo com as especificações definidas para o produto, nomeadamente a avaliação à corrosão, o brilho, o índice de amarelecimento e a aplicabilidade. Na primeira parte do trabalho foi analisada a influência das diferentes matérias-primas presentes na formulação. Foram testados quatro grupos de matérias-primas cruciais para o desenvolvimento do esmalte: resinas, espessantes, dispersantes e aditivos específicos contra a corrosão. Desta forma, definiram-se as formulações a testar experimentalmente. Seguidamente, depois de fabricados os ensaios, à escala laboratorial, analisaram-se diversos parâmetros como a viscosidade, brancura e razão de contraste. Os ensaios que cumpriam as especificações definidas para o produto, passaram à segunda parte do trabalho na qual se avaliou o comportamento relativamente à corrosão e a aplicabilidade da tinta. Na segunda parte do trabalho, os ensaios analisados foram aplicados em chapas com ferrugem e colocados no exterior, onde foi avaliado o seu comportamento relativamente à corrosão. Para além disso, os mesmos ensaios foram aplicados em chapas sem ferrugem e estas foram colocadas na câmara de envelhecimento acelerado, onde se avaliou a degradação da película seca, nomeadamente a perda de brilho e o índice de amarelecimento. Nesta fase foi ainda analisada a aplicabilidade da tinta, tendo-se avaliado a lacagem, a facilidade de espalhamento e a espessura de camada debitada. Dos três ensaios analisados, A.2, B.4 e C.4, o esmalte A.2 foi o que apresentou uma melhor performance na conversão de ferrugem e proteção anticorrosiva. No entanto, este ensaio apresentou uma elevada degradação de película seca, nomeadamente um elevado índice de amarelecimento (1,5%) e perda de brilho (65,1%). Tendo em conta os resultados obtidos, sugere-se a continuidade do trabalho com base na formulação utilizada no ensaio A.2, mas utilizando um aditivo anticorrosivo diferente, uma vez que se verificou que este causava a degradação da película seca.
The main objective of this work was to develop a direct aqueous rust enamel. The product is intended to convert the pre-existing rust, provide long-term corrosion protection, and inhibit instant rust. For comparison purposes, three commercially available products, two aqueous base enamels of other compagnies, and the solvent-based enamel of the Fábrica de Tintas 2000, were analyzed. The work was divided in two parts: the study of the influence of the different raw materials in the tests performed, which allowed readjusting the formulation until the best one was obtained, and the analysis of the tests in accordance with the specifications defined for the product, such as the evaluation of corrosion, gloss, yellowing index, and applicability. In the first part of the work, four groups of raw materials crucial to the development of the enamel were tested, namely resins, thickeners, dispersants, and specific anti-corrosion additives. In this way, the formulations to be experimentally tested were selected. Then, after performing the assays, on a laboratory scale, several parameters such as viscosity, whiteness and contrast ratio were analyzed. The assays that displayed an appropriate performance in accordance with the set specifications for the product were further evaluated regarding their corrosion behavior and applicability of the paint. In the second part of the study, the analyzed tests were applied to sheets with rust and placed outdoors, and subsequently their corrosion behavior was assessed. Furthermore, the same tests were applied to sheets without rust and placed in an accelerated aging chamber to evaluate the degradation of the dry film, namely the loss of brightness and the yellowing index. At this stage, the applicability of the paint was also analyzed by evaluating the lacquering, the ease of spreading, and the thickness of the debited layer. Of the three tests analyzed, A.2, B.4 and C.4, the enamel A.2 was the one that showed the best performance in rust conversion and anticorrosion protection. However, this trial showed a high dry film degradation, namely a high yellowing index (1,5%) and gloss loss (65,1%). In view of the results obtained, it is suggested do continue the work, based on the formulation used in test A.2, but using a different anticorrosion additive, since it was found to cause dry film degradation.
The main objective of this work was to develop a direct aqueous rust enamel. The product is intended to convert the pre-existing rust, provide long-term corrosion protection, and inhibit instant rust. For comparison purposes, three commercially available products, two aqueous base enamels of other compagnies, and the solvent-based enamel of the Fábrica de Tintas 2000, were analyzed. The work was divided in two parts: the study of the influence of the different raw materials in the tests performed, which allowed readjusting the formulation until the best one was obtained, and the analysis of the tests in accordance with the specifications defined for the product, such as the evaluation of corrosion, gloss, yellowing index, and applicability. In the first part of the work, four groups of raw materials crucial to the development of the enamel were tested, namely resins, thickeners, dispersants, and specific anti-corrosion additives. In this way, the formulations to be experimentally tested were selected. Then, after performing the assays, on a laboratory scale, several parameters such as viscosity, whiteness and contrast ratio were analyzed. The assays that displayed an appropriate performance in accordance with the set specifications for the product were further evaluated regarding their corrosion behavior and applicability of the paint. In the second part of the study, the analyzed tests were applied to sheets with rust and placed outdoors, and subsequently their corrosion behavior was assessed. Furthermore, the same tests were applied to sheets without rust and placed in an accelerated aging chamber to evaluate the degradation of the dry film, namely the loss of brightness and the yellowing index. At this stage, the applicability of the paint was also analyzed by evaluating the lacquering, the ease of spreading, and the thickness of the debited layer. Of the three tests analyzed, A.2, B.4 and C.4, the enamel A.2 was the one that showed the best performance in rust conversion and anticorrosion protection. However, this trial showed a high dry film degradation, namely a high yellowing index (1,5%) and gloss loss (65,1%). In view of the results obtained, it is suggested do continue the work, based on the formulation used in test A.2, but using a different anticorrosion additive, since it was found to cause dry film degradation.
Description
Keywords
Ferrugem Brilho Amarelecimento Anticorrosivo Corrosão Resinas acrílicas Rust Gloss Yellowing Anticorrosive Corrosion Acrylic resins