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Abstract(s)
A cortiça é cada vez mais utilizada como material de construção. Quando se utiliza cortiça na construção civil, é comum protegê-la com tintas e vernizes. No entanto, a cortiça é um material que traz alguns problemas: libertação de taninos que mancham tintas de cor clara, tem tendência a perder cor por exposição solar e precisa de ter um revestimento com suficiente resistência à abrasão. Assim, o objetivo deste trabalho foi desenvolver e caracterizar um sistema de pintura à base de água para ser aplicado diretamente em folhas de cortiça. As principais propriedades estudadas foram o bloqueio à migração de taninos, a força de colagem a uma folha de PVC para aplicações em pavimentos e a aderência do revestimento à cortiça. O projeto foi dividido em cinco fases principais: 1) caracterização de solventes, 2) caracterização de resina, 3) seleção de aditivos anti-taninos, 4) seleção de cargas e 5) avaliação global dos resultados e ajuste da formulação, i.e., reformulação. A caracterização do solvente foi realizada por meio de dois testes, avaliação da solubilidade dos taninos em diversos co-solventes e em água a diferentes valores de pH. Nove co-solventes foram selecionados e os melhores resultados foram obtidos com XXXX, XXXX e XXXX, que puderam ser utilizados na formulação subsequente e testados para ligantes, agentes anti-taninos e cargas. Os taninos são menos solúveis se o pH for mantido entre 4-6. A seleção da resina, aditivo anti-taninos e das cargas baseou-se nos resultados do teste de aderência ao PVC, adesão à cortiça e nos testes de migração de taninos. As resinas C1 e V1 mostraram ter propriedades apropriadas. O agente anti-taninos, XXXX, também apresentou características apropriadas para a resina R1. Além disso, as cargas F9 (XXXX) exibiu o melhor desempenho em manter o pH baixo do primário, mas menor aderência. As mudanças na formulação usando C1 e R1 contribuíram para resolver o problema da aderência. Por outro lado, uma abordagem diferente, usando dois revestimentos, isto é, V1.1 como selante e O1.1 como um revestimento superior, foi introduzida na reformulação. V1 foi combinado com o F9 e o XXXX. O selante V1.1 foi aplicado para bloquear a migração dos taninos e o O1.1 foi usado para conferir opacidade e aderência ao PVC no acabamento. A formulação composta pelo solvente XXXX, a resina V1 e O1, o agente anti-taninos XXXX e as cargas F9, foi a que permitiu atingir os objetivos propostos. A formulação desenvolvida tem grande interesse na proteção de cortiça.
Cork is increasingly used as a flooring in homes, whether on pavements or on walls. When using cork in civil construction, it is common to protect it with paints and varnishes. But cork is a material that brings some problems: tannins that stain light-colored paints, tend to lose color through sun exposure and need to have a coating with sufficient abrasion resistance. Thus, the goal of this work was to develop and characterize a waterbased paint system to be applied directly to cork sheets. The main studied properties were the tannin blocking performance, gluing strength to a PVC sheet and tackiness. The project may be divided on five main phases: 1) solvent characterization, 2) resin characterization, 3) anti-tannins additives selection, 4) filler/extender selection and 5) overall assessment of the results and reformulation in order to successfully achieved the set goal. The solvent characterization was performed using two tests, the solubility of tannin in a co-solvent and in water at different pH values. Nine co-solvents were selected and the best results were obtained with XXXX, XXXX and XXXX, which could be used in the subsequent formulation and tested for binders, anti-tannin agent and extenders. Tannins are less soluble if the pH is maintained between 4-6. The selection of the resin, anti-tannin additive and fillers was based on the outcomes of the test of adhesion to PVC, test for tackiness, adhesion to cork and on the tannin tests. Resins C1 and V1 showed appropriate properties. The anti-tannin agent, i.e. XXXX, gave appropriate characteristics for the resin R1. Also, the filler F9 (XXXX) outcomes were the best in maintaining low pH of primer and less tackiness. The changes in the formulation using C1 and R1 contributed to resolve the problem of tackiness. On other hand, a different technology, using two coatings, i.e. V1.1 as a sealer and O1.1 as a topcoat, was introduced in the reformulation. V1 was combined with filler F9 and XXXX. The sealer V1.1 was applied to block the tannin migration, and O1.1 was used to give opacity and adhesion to PVC in the topcoat. The formulation composed by the solvent XXXX, the resin V1 and O1, the antitannin agent XXXX and the filler F9, was the best one to attain the proposed goals i.e. good adhesion to PVC, less tackiness, adhesion to cork, blocking action to tannins migration and good stability in climatic chamber tests. The developed formulation has high interest for cork sheets protection.
Cork is increasingly used as a flooring in homes, whether on pavements or on walls. When using cork in civil construction, it is common to protect it with paints and varnishes. But cork is a material that brings some problems: tannins that stain light-colored paints, tend to lose color through sun exposure and need to have a coating with sufficient abrasion resistance. Thus, the goal of this work was to develop and characterize a waterbased paint system to be applied directly to cork sheets. The main studied properties were the tannin blocking performance, gluing strength to a PVC sheet and tackiness. The project may be divided on five main phases: 1) solvent characterization, 2) resin characterization, 3) anti-tannins additives selection, 4) filler/extender selection and 5) overall assessment of the results and reformulation in order to successfully achieved the set goal. The solvent characterization was performed using two tests, the solubility of tannin in a co-solvent and in water at different pH values. Nine co-solvents were selected and the best results were obtained with XXXX, XXXX and XXXX, which could be used in the subsequent formulation and tested for binders, anti-tannin agent and extenders. Tannins are less soluble if the pH is maintained between 4-6. The selection of the resin, anti-tannin additive and fillers was based on the outcomes of the test of adhesion to PVC, test for tackiness, adhesion to cork and on the tannin tests. Resins C1 and V1 showed appropriate properties. The anti-tannin agent, i.e. XXXX, gave appropriate characteristics for the resin R1. Also, the filler F9 (XXXX) outcomes were the best in maintaining low pH of primer and less tackiness. The changes in the formulation using C1 and R1 contributed to resolve the problem of tackiness. On other hand, a different technology, using two coatings, i.e. V1.1 as a sealer and O1.1 as a topcoat, was introduced in the reformulation. V1 was combined with filler F9 and XXXX. The sealer V1.1 was applied to block the tannin migration, and O1.1 was used to give opacity and adhesion to PVC in the topcoat. The formulation composed by the solvent XXXX, the resin V1 and O1, the antitannin agent XXXX and the filler F9, was the best one to attain the proposed goals i.e. good adhesion to PVC, less tackiness, adhesion to cork, blocking action to tannins migration and good stability in climatic chamber tests. The developed formulation has high interest for cork sheets protection.
Description
Keywords
Taninos Cortiça PVC Tintas Aditivo Anti-tanino Tannins Cork Paints Sealers Anti-tannin additive