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Abstract(s)
O objetivo do trabalho consistiu em reduzir o efeito snail trail de uma tinta de base aquosa, um problema comum neste tipo de tintas. Este problema consiste na mudança do aspeto da película aplicada, que ocorre após exposição no ambiente exterior. Foi necessário recorrer ao estudo de cada Matéria Prima (MP) para tentar eliminar ou reduzir a patologia. Através do estudo, percebeu-se que era necessário recorrer à eliminação ou alteração das MPs para reduzir o problema. O trabalho dividiu-se em duas partes: estudar a influência das matérias primas no efeito snail trail da formulação da tinta, percebendo qual a MP ou conjuntos de MPs que eram causadoras da patologia, e testar novas matérias primas para perceber se tinham a capacidade de eliminar ou reduzir este problema. No teste das matérias primas foi analisada a influência das quando todas estavam presentes na formulação e também qual o comportamento de cada uma de forma isolada. Isto é, conforme a MP era introduzida no fabrico, retirava-se uma amostra para ser aplicada na folha Leneta para realização do teste snail trail. Com os primeiros ensaios detetou-se que o Regulador de Dureza da Água (RDA) e o Compatibilizante eram as principais MPs que afetavam o snail trail. Por essa razão, fizeram-se ensaios para testar diferentes percentagens mássicas dos dois componentes para perceber se a variação influenciava na patologia. Foram também analisados diversos parâmetros como a viscosidade, densidade, razão de contraste e força corante. Também foram avaliadas outras características como os parâmetros CIELab (sistema que permite medir a cor numericamente), mud-cracking (teste para avaliar a fissuração da tinta a espessuras diferentes) e aplicação a rolo no exterior. Com os resultados obtidos, concluiu-se que na ausência total do compatibilizante e do RDA existiam melhorias no efeito snail trail e que através de ajustes na formulação era possível cumprir as especificações de controlo da tinta. O teste de novas MPs consistiu na substituição direta na formulação pela MP correspondente. Foram testadas 2 resinas acrílicas, um espessante e um dispersante e, por fim, um aditivo para redução do snail trail. Concluiu-se que a utilização destas MPs na formulação não é vantajoso na eliminação ou redução do efeito snail trail Tendo em conta os resultados obtidos, sugere-se a continuidade do trabalho, mas noutras tintas onde está presente a patologia, pelo que o ponto de partida para a resolução é perceber qual o resultado do snail trail na ausência do RDA e do compatibilizante.
The scope of the work was the minimize the snail trail effect on aqueoes paint, a common problem that is found in this sort of paint. The snail trail effect is the change of the aspect of the film once it is exposed to external conditions. To try to solve or eliminate this problem, a study of the different the different components of the paint was carried out. One of the conclusions of the study was that some components must be taken out of the composition of the paint in order to prevent the snail trail. The work was divided into two parts. First, the study of the influence of the composition of the paint in its snail trail effect was carried out. This would allow to understand which components had a major influence in this problem. Secondly, new techniques and components were tested in the hope of eliminating or reducing the snail trail effect. Component testing was performed with them all together in the paint composition and isolated from each other. This means that according to the competent added in the manufacturing process, a sample was taken and tested in a Leneta chart. The first experiments demonstrated that Water Hardness Regulators (WHR) and compatibilizers has a greater effect on the snail trail than other components. Therefore, new experiments with different mass ratios of these two components were performed. Other parameters were also subject of study, such as, viscosity, density, contrast ratio, shear force. Furthermore, other parameters were also studied, such as, CIELab parameters, mud-cracking and roll application on a surface. The obtained results indicated that the absence of WHR and compatibilizers mitigated the problem of the snail trail effect and that with adaptations in the composition of the paint it is possible to fulfill its quality control requirements. The test of new components consisted in switching two existing components for two new acrylic resins- a thickener and a dispersant and a new additive for the reduction of the snail trail effect. It was concluded that the addiction of these components did not benefit the reduction or elimination of the snail trail effect. Taking into account the results of this work, it is recommended to continue it in other types of paint were this problem is also present. The new starting point of such new studies should be understanding what the result of the snail trail is when RDA and compatibilizers are absent.
The scope of the work was the minimize the snail trail effect on aqueoes paint, a common problem that is found in this sort of paint. The snail trail effect is the change of the aspect of the film once it is exposed to external conditions. To try to solve or eliminate this problem, a study of the different the different components of the paint was carried out. One of the conclusions of the study was that some components must be taken out of the composition of the paint in order to prevent the snail trail. The work was divided into two parts. First, the study of the influence of the composition of the paint in its snail trail effect was carried out. This would allow to understand which components had a major influence in this problem. Secondly, new techniques and components were tested in the hope of eliminating or reducing the snail trail effect. Component testing was performed with them all together in the paint composition and isolated from each other. This means that according to the competent added in the manufacturing process, a sample was taken and tested in a Leneta chart. The first experiments demonstrated that Water Hardness Regulators (WHR) and compatibilizers has a greater effect on the snail trail than other components. Therefore, new experiments with different mass ratios of these two components were performed. Other parameters were also subject of study, such as, viscosity, density, contrast ratio, shear force. Furthermore, other parameters were also studied, such as, CIELab parameters, mud-cracking and roll application on a surface. The obtained results indicated that the absence of WHR and compatibilizers mitigated the problem of the snail trail effect and that with adaptations in the composition of the paint it is possible to fulfill its quality control requirements. The test of new components consisted in switching two existing components for two new acrylic resins- a thickener and a dispersant and a new additive for the reduction of the snail trail effect. It was concluded that the addiction of these components did not benefit the reduction or elimination of the snail trail effect. Taking into account the results of this work, it is recommended to continue it in other types of paint were this problem is also present. The new starting point of such new studies should be understanding what the result of the snail trail is when RDA and compatibilizers are absent.
Description
Keywords
Snail trail Compatibilizante Regulador de dureza da água Resinas acrílicas Compatibilizers Water Hardness Regulator Acrylic Resins