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Desenvolvimento de um sistema adesivo para a produção de painéis de contraplacado com emissões ao nível da legislação E05
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Abstract(s)
Os painéis derivados de madeira apresentam-se como uma alternativa aos produtos de madeira maciça. Dentro destes, os mais conhecidos são os contraplacados (PW), os painéis aglomerados de partícula (PB) e os aglomerados de fibras de média densidade (MDF). A produção destes painéis envolve a utilização de resinas termoendurecíveis, com destaque das resinas amino. No entanto, estas resinas apresentam como problema a emissão de formaldeído, um composto volátil prejudicial a saúde humana. Como consequência, têm vindo a ser
implementadas legislações mais restritivas quanto à emissão de formaldeído (EF), como a nova legislação europeia E05, que impõe um limite de 0,062 mg/m³. O presente trabalho teve como objetivo desenvolver sistemas adesivos a partir de resinas amino para a produção de contraplacados com EF ao nível da legislação E05. Para tal, foram realizados cinco estudos experimentais em que se analisou as EF dos contraplacados produzidos pelo método de análise de gás (ISO 12460-3), tendo-se definido como valor de referência o limite de 1,0 mg/(m2·h). No primeiro estudo, testou-se 4,8 % dos captadores 1,2 e 3 nas resinas A (UF), B (UF) e C (MUF), destacando-se o captador 2 com valores de EF reduzidas, especialmente em formulações com resina C (1.6 mg/(m2·h)). No segundo estudo, aprofundou-se a análise do captador 2 nas concentrações 3,6; 4,9 e 6,9 % com as resinas E (MUF) e F (UF), demonstrando que todas as formulações com a resina E apresentaram valores de EF mais reduzidos, destacando-se a concentração de 4,9 % (0,7 mg/(m2·h)). O terceiro estudo avaliou-se na redução
da razão molar (RM) através da combinação de resinas A (UF) e D (MUF) nas seguintes proporções mássicas: 55; 45 e 40 % da resina A, com RM de RM7; RM8 e RM9, respetivamente. Observou-se uma diminuição nas EF, destacando-se a proporção de 40 % (1,5 mg/(m2·h)) de resina A que apresentou o valor EF mais reduzida. No quarto estudo, combinou-se a estratégia do estudo anterior com a adição de 3,6 % do captador 2, pelo que atingiu um valor de EF inferior ao limite da classe E05 (0,8 mg/(m2·h)). Por fim, o quinto estudo explorou dois novos captadores: bicarbonato de amónio e a propilamina. Ambos apresentaram valores de EF reduzidos, com as concentrações de 3,5 % (1,1 mg/(m2·h)) e 0,3 % (1,3 mg/(m2·h)), respetivamente. Com base nos resultados obtidos, pode-se concluir que o objetivo do trabalho foi atingido, atendendo as necessidades da indústria para produção de contraplacado e contribuindo para a melhoria da qualidade do ar interior e proteção da saúde humana.
Wood-based panels are an alternative to solid wood products. Among these, the most wellknown are plywood (PW), particleboard (PB), and medium-density fiberboard (MDF). The production of these panels involves the use of thermosetting resins, with a particular focus on amino resins. However, these resins pose a problem due to the emission of formaldehyde, a volatile compound harmful to human health. As a result, stricter regulations have been implemented regarding formaldehyde emissions (FE), such as the new European legislation E05, which imposes a limit of 0,062 mg/m³. This study aimed to develop adhesive systems based on amino resins for the production of plywood with FE levels in compliance with the E05 regulation. To this end, five experimental studies were carried out to analyze the FE of the plywood produced using the gas analysis method (ISO 12460-3), setting the reference limit at 1,0 mg/(m²·h). In the first study, 4,8 % of scavengers 1, 2, and 3 were tested in resins A (UF), B (UF) and C (MUF), with scavenger 2 standing out for its lower FE values, especially in formulations with resin C (1,6 mg/(m²·h)). In the second study, scavenger 2 was further analyzed at concentrations of 3,6; 4,9 and 6,9 % with resins E (MUF) and F (UF), showing that all formulations with resin E exhibited lower FE values, with the 4,9 % concentration being the most effective (0,7 mg/(m²·h)). The third study evaluated the reduction of the molar ratio (MR) by combining resins A (UF) and D (MUF) in the following mass proportions: 55; 45 and 40 % of resin A, with MR values of MR7, MR8, and MR9, respectively. A decrease in FE was observed, with the 40 % proportion of resin A showing the lowest FE value (1,5 mg/(m²·h)). In the fourth study, the previous strategy was combined with the addition of 3,6 % of scavenger 2, resulting in an FE value below the E05 class limit (0,8 mg/(m²·h)). Finally, the fifth study explored two new scavengers: ammonium bicarbonate and propylamine. Both showed reduced FE values, with concentrations of 3,5 % (1,1 mg/(m²·h)) and 0,3 % (1,3 mg/(m²·h)), respectively. Based on the results obtained, it can be concluded that the objective of the study was achieved, meeting the needs of the plywood industry and contributing to improved indoor air quality and the protection of human health.
Wood-based panels are an alternative to solid wood products. Among these, the most wellknown are plywood (PW), particleboard (PB), and medium-density fiberboard (MDF). The production of these panels involves the use of thermosetting resins, with a particular focus on amino resins. However, these resins pose a problem due to the emission of formaldehyde, a volatile compound harmful to human health. As a result, stricter regulations have been implemented regarding formaldehyde emissions (FE), such as the new European legislation E05, which imposes a limit of 0,062 mg/m³. This study aimed to develop adhesive systems based on amino resins for the production of plywood with FE levels in compliance with the E05 regulation. To this end, five experimental studies were carried out to analyze the FE of the plywood produced using the gas analysis method (ISO 12460-3), setting the reference limit at 1,0 mg/(m²·h). In the first study, 4,8 % of scavengers 1, 2, and 3 were tested in resins A (UF), B (UF) and C (MUF), with scavenger 2 standing out for its lower FE values, especially in formulations with resin C (1,6 mg/(m²·h)). In the second study, scavenger 2 was further analyzed at concentrations of 3,6; 4,9 and 6,9 % with resins E (MUF) and F (UF), showing that all formulations with resin E exhibited lower FE values, with the 4,9 % concentration being the most effective (0,7 mg/(m²·h)). The third study evaluated the reduction of the molar ratio (MR) by combining resins A (UF) and D (MUF) in the following mass proportions: 55; 45 and 40 % of resin A, with MR values of MR7, MR8, and MR9, respectively. A decrease in FE was observed, with the 40 % proportion of resin A showing the lowest FE value (1,5 mg/(m²·h)). In the fourth study, the previous strategy was combined with the addition of 3,6 % of scavenger 2, resulting in an FE value below the E05 class limit (0,8 mg/(m²·h)). Finally, the fifth study explored two new scavengers: ammonium bicarbonate and propylamine. Both showed reduced FE values, with concentrations of 3,5 % (1,1 mg/(m²·h)) and 0,3 % (1,3 mg/(m²·h)), respectively. Based on the results obtained, it can be concluded that the objective of the study was achieved, meeting the needs of the plywood industry and contributing to improved indoor air quality and the protection of human health.
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Keywords
Adhesive system Amino resins Formaldehyde emission Plywood Sistema adesivo Resinas amino Emissão de formaldeído Contraplacado