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Abstract(s)
O calçado é um dos artigos indispensáveis no quotidiano. Um dos materiais mais utilizados no fabrico de calçado é o poliuretano (PU) microcelular. Deste processo resultam resíduos, que podem ser descartados para aterros ou serem valorizados por métodos químicos, termoquímicos ou físicos. Este trabalho realizou-se na empresa JP Super Soles. O objetivo foi avaliar se o PU microcelular resultante da produção de artigos para calçado poderia ser incorporado para a produção de novas solas. Na produção dos materiais, utilizou-se um sistema de extrusão já existente na empresa para o fabrico de artigos em cortiça. Devido a limitações do sistema, testou-se a introdução de percentagem de resíduos entre 22 % e 44 %. Como era necessário manter-se a densidade das peças na gama 0,55-0,65 g/cm3 , reduziu-se a massa de resina de PU à medida que se aumentou a percentagem de resíduos. As propriedades testadas foram a dureza, resistência à abrasão, tensão de rotura, alongamento na rotura, módulo de Young, resistência ao rasgamento máxima, resistência ao rasgamento média, e resistência elétrica. Esta última propriedade foi avaliada porque os resíduos utilizados tinham um aditivo antiestático na composição. A incorporação de resíduos teve uma influência negativa nas propriedades do novo material produzido. Os novos materiais produzidos não se encontravam dentro dos parâmetros definidos pela empresa para a produção de solas de sapatos. A reciclagem física de PU realizada, permite recuperar os resíduos ao mesmo tempo que se reduz a quantidade de matéria-prima utilizada, mas como consequência ocorre perda de propriedades do material. Novos estudos devem ser realizados de modo a avaliar se a introdução de PU reciclado na produção de solas de sapatos é possível, cumprindo as caraterísticas desejadas pela empresa.
Footwear is an indispensable item in daily life. One of the most used materials in shoe manufacture is microcellular polyurethane (PU). As a result of this process, waste is produced, which can be disposed of in landfills or recovered by chemical, thermochemical or physical methods. This work was carried out in the company JP Super Soles. The objective was to evaluate if the microcellular PU wastes generated from the production of footwear could be incorporated to produce new soles. The production of the materials was carried out using an extrusion system already existing in the company for the manufacture of cork composites soles. Due to the limitations of the system, the percentage of waste was between 22% and 44%. As the density of the pieces had to be kept within the 0.55-0.65 g/cm3 range, the mass of PU resin was reduced as the percentage of waste increased. The properties evaluated were hardness, abrasion resistance, tensile strength, elongation at break, Young's modulus, maximum tear strength, average tear strength, and electrical resistance. This last property was evaluated since the waste used had an antistatic additive in its composition. There was a negative influence in the properties with the incorporation of waste. The new materials produced were not within the parameters set by the company to produce shoe soles. The physical recycling of PU performed, allows to recover the waste while reducing the amount of raw material used, but consequently there is a loss of material properties. Further studies should be conducted to assess whether the introduction of recycled PU in the production of shoe soles is possible, fulfilling the characteristics desired by the company.
Footwear is an indispensable item in daily life. One of the most used materials in shoe manufacture is microcellular polyurethane (PU). As a result of this process, waste is produced, which can be disposed of in landfills or recovered by chemical, thermochemical or physical methods. This work was carried out in the company JP Super Soles. The objective was to evaluate if the microcellular PU wastes generated from the production of footwear could be incorporated to produce new soles. The production of the materials was carried out using an extrusion system already existing in the company for the manufacture of cork composites soles. Due to the limitations of the system, the percentage of waste was between 22% and 44%. As the density of the pieces had to be kept within the 0.55-0.65 g/cm3 range, the mass of PU resin was reduced as the percentage of waste increased. The properties evaluated were hardness, abrasion resistance, tensile strength, elongation at break, Young's modulus, maximum tear strength, average tear strength, and electrical resistance. This last property was evaluated since the waste used had an antistatic additive in its composition. There was a negative influence in the properties with the incorporation of waste. The new materials produced were not within the parameters set by the company to produce shoe soles. The physical recycling of PU performed, allows to recover the waste while reducing the amount of raw material used, but consequently there is a loss of material properties. Further studies should be conducted to assess whether the introduction of recycled PU in the production of shoe soles is possible, fulfilling the characteristics desired by the company.
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Keywords
Poliuretano (PU) Reciclagem física Calçado Propriedades Polyurethane (PU) Physical recycling Footwear Properties