| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 4.9 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
Com este projeto, pretende-se a formulação de um revestimento com um tempo de cura total de aproximadamente 24 horas, ao contrário dos sistemas tradicionais epoxídicos e de poliuretano que têm um tempo de cura de 7 dias. Foram estudados 5 tipos de resinas aspárticas, 2 tipos de resinas de policarbamida e 2 tipos de endurecedor de isocianato (com solventes e sem solventes). Foram ainda avaliados 3 tipos de endurecedores de amina utilizados em sistemas epoxídicos de cura rápida. Por último avaliouse o comportamento dos sistemas epoxídicos e poliuretano tradicionais na presença de catalisador. O estudo inicial destes sistemas consistiu em avaliar o seu tempo de vida, tempo de secagem, dureza pendular de Kӧnig, back to service time (cura em 24 horas) e aderência direta no betão. Posteriormente foi formulada e produzida uma base branca para cada sistema onde a avaliação foi realizada com os mesmos métodos e realizaram-se ainda testes de envelhecimento. Na generalidade, conclui-se que o sistema com melhores resultados é o poliaspártico. Posteriormente foram realizadas melhorias na formulação do sistema poliaspártico como a remoção de cargas que estavam a prejudicar a dureza, a adição de um adsorvedor de humidade para aumentar ligeiramente o tempo de vida e a inclusão de um aditivo para dispersar e impedir a floculação do dióxido de titânio e dos pigmentos. O produto foi aprovado com uma proporção resina/endurecedor de 2,7:2,3 em volume e posteriormente adequado a um sistema tintométrico já existente na Barbot. Por fim, realizou-se a caracterização do sistema. Verificou-se que o produto final possui um tempo de vida de 20 minutos e seca totalmente em 30 minutos. Tem uma opacidade superior a 90 e consegue atingir um brilho de 85,7 para a geometria de 20º. É um produto com boa resistência a intempéries visto que o seu Db* é inferior a 1 após 1200 horas de exposição a luz UV. Atinge uma dureza de 108,73 segundos em 24 horas, ou seja, 85% da sua dureza final de 145,6 segundos, pelo que a cura não está totalmente completa num dia. Perde apenas 114 mg nos ensaios de resistência à abrasão, possui uma dureza lápis de 3B e tem flexibilidade total no mandril cónico. Resiste à fissuração até um impacto de 7,36 N. Quando em contacto 24 horas com produtos líquidos, demonstra danos principalmente com solventes.
With this project, it is intended to formulate a coating with a total cure time of approximately 24 hours, unlike traditional epoxy and polyurethane systems that have a cure time of 7 days. Five types of aspartic resins, two types of polycarbamide resins and two types of isocyanate hardener were studied. Three types of amine hardeners used in fast curing epoxy systems were evaluated too. Finally, it was also evaluated the behavior of traditional epoxy and polyurethane systems in the presence of catalyst. The initial study of these systems consisted in evaluating their pot-life, drying time, pendulum hardness and direct adhesion on concrete. Subsequently, a white base was formulated and produced for each system where the evaluation was made with the same methods and aging testes were also performed. In general, it is concluded that the system with the best results is the polyaspartic. Following this, improvements were made to the formulation of the polyaspartic system such as the removal of fillers that were reducing hardness, the addition of a moisture adsorber to slightly increase pot-life and the inclusion of an additive to disperse titanium dioxide. The product was approved with a resin/hardener ratio of 2,7:2,3 in volume and later adapted to an existing tinting system at Barbot. Finally, the characterization of the systems was carried out. The final product has a pot-life of 20 minutes and dries completely in 30 minutes. It has an opacity of over 90 and can achieve a gloss of 85,7 for the 20º geometry. It is a product with good weather resistance as its Db* is less than 1 after 1200 hours of exposure to UV light. It reaches hardness of 108,73 seconds in 24 hours, 85% of its final hardness of 145,6 seconds, so the cure is not complete in one day. It loses only 114 mg in abrasion tests, has a pencil hardness of 3B, and has full flexibility in the conic mandrel. It resists cracking up to an impact of 7,36 N. When in 24-hour contact with liquid product, it shows damage mostly with solvents.
With this project, it is intended to formulate a coating with a total cure time of approximately 24 hours, unlike traditional epoxy and polyurethane systems that have a cure time of 7 days. Five types of aspartic resins, two types of polycarbamide resins and two types of isocyanate hardener were studied. Three types of amine hardeners used in fast curing epoxy systems were evaluated too. Finally, it was also evaluated the behavior of traditional epoxy and polyurethane systems in the presence of catalyst. The initial study of these systems consisted in evaluating their pot-life, drying time, pendulum hardness and direct adhesion on concrete. Subsequently, a white base was formulated and produced for each system where the evaluation was made with the same methods and aging testes were also performed. In general, it is concluded that the system with the best results is the polyaspartic. Following this, improvements were made to the formulation of the polyaspartic system such as the removal of fillers that were reducing hardness, the addition of a moisture adsorber to slightly increase pot-life and the inclusion of an additive to disperse titanium dioxide. The product was approved with a resin/hardener ratio of 2,7:2,3 in volume and later adapted to an existing tinting system at Barbot. Finally, the characterization of the systems was carried out. The final product has a pot-life of 20 minutes and dries completely in 30 minutes. It has an opacity of over 90 and can achieve a gloss of 85,7 for the 20º geometry. It is a product with good weather resistance as its Db* is less than 1 after 1200 hours of exposure to UV light. It reaches hardness of 108,73 seconds in 24 hours, 85% of its final hardness of 145,6 seconds, so the cure is not complete in one day. It loses only 114 mg in abrasion tests, has a pencil hardness of 3B, and has full flexibility in the conic mandrel. It resists cracking up to an impact of 7,36 N. When in 24-hour contact with liquid product, it shows damage mostly with solvents.
Description
Keywords
Sistema poliaspártico Resina Cura Revestimentos Pavimentos Polyaspartic system Resin Curing Coatings Flooring