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Abstract(s)
A Indústria do Calçado e, principalmente, a Indústria dos Curtumes, produzem grandes quantidades de resíduos sólidos. A maior parte destes resíduos é depositada em aterro, desperdiçando-se o seu conteúdo e contribuindo para problemas ambientais. O trabalho desenvolvido teve por objetivo valorizar estes resíduos e estudar a viabilidade da produção de aglomerados para aplicação como palmilhas para calçado. Para este efeito, a metodologia seguida foi: hidrólise alcalina dos resíduos de couro moídos, mistura com ligante e plastificante, prensagem e secagem. Procurou-se, numa fase inicial, encontrar as melhores condições experimentais para a formação dos aglomerados, desde as quantidades de água, hidróxido de sódio, ligante e plastificante, como também a temperatura da hidrólise ou, ainda, a pressão e o tempo de prensagem. Uma vez obtidos os aglomerados, procedeu-se à realização de vários ensaios físicomecânicos e avaliaram-se os resultados com base nos requisitos para palmilhas. Os aglomerados que apresentaram melhores características e resultados nos testes físicos foram os preparados com produtos desenvolvidos a partir de resina de pinheiro. Os testes físicos realizados e respetivos requisitos foram: resistência ao rasgamento igual
ou superior a 15N, absorção e dessorção de água de 70 mg/cm2 e de 60%, respetivamente, 25600 ciclos no ensaio de abrasão Martindale sem desgaste nem descoloração significativos, resistência à delaminação igual ou superior a 650 kPa e índice de flexão igual ou superior a 3,3. Os melhores aglomerados produzidos apresentaram os seguintes resultados: 19N no teste de resistência ao rasgamento, uma absorção de 69,9 mg/cm2 e uma dessorção de 76,7%, ensaio de abrasão sem evidenciar desgaste, alteração de cor ou diminuição de espessura relevantes, resistência à delaminação de 64,1 kPa e índice de flexão igual a 1,1.
Em suma, conclui-se que nesta fase, nenhum dos aglomerados produzidos está preparado para sofrer a ação e desgaste a que está sujeita uma palmilha, evidenciando uma coesão interna e uma resistência ao movimento de flexão repetitivo ainda fracas para a aplicação pretendida.
The Footwear Industry and, especially the Tanning Industry, produce large amounts of solid waste. Most of these residues are deposited in landfills, thereby wasting their substance and contributing to environmental problems. The purpose of this project has been to value these waste materials and study the viability of producing agglomerates to be used as shoe insoles. To this aim, the methodology followed was: alkaline hydrolysis of ground leather waste, mixture with a binding agent and plasticizer, pressing, and drying. At an early stage, efforts were made to find the best experimental conditions for the formation of agglomerates, ranging from the amounts of water, sodium hydroxide, binder, and plasticizer, as well as the hydrolysis temperature or even the pressing time and pressure. Once the agglomerates had been obtained, they were tested in various physicalmechanical tests and the results were evaluated based on the requirements for insoles. The agglomerates with the best characteristics and results in the physical tests were those prepared with products made from pinewood resin. The physical tests and respective requirements performed were: tear strength equal to or higher than 15N, water absorption and desorption of 70 mg/cm2 and 60% respectively, 25600 cycles in the Martindale abrasion test without significant deterioration or discoloration, delamination resistance equal to or higher than 650 kPa and flexing index equal to or higher than 3,3. The best agglomerates produced presented the following results: 19N in the tear resistance test, an absorption of 69,9 mg/cm2 and a desorption of 76,7%, an abrasion test with no evidence of deterioration, color change, or significant reduction in thickness, a delamination resistance of 64,1 kPa and a flexing index equal to 1,1. To summarize, at this stage it can be concluded that none of the produced agglomerates is ready to suffer the action and tear to which an insole is subjected, demonstrating an internal cohesion and repeated bending movement resistance that is still insufficient for the intended application.
The Footwear Industry and, especially the Tanning Industry, produce large amounts of solid waste. Most of these residues are deposited in landfills, thereby wasting their substance and contributing to environmental problems. The purpose of this project has been to value these waste materials and study the viability of producing agglomerates to be used as shoe insoles. To this aim, the methodology followed was: alkaline hydrolysis of ground leather waste, mixture with a binding agent and plasticizer, pressing, and drying. At an early stage, efforts were made to find the best experimental conditions for the formation of agglomerates, ranging from the amounts of water, sodium hydroxide, binder, and plasticizer, as well as the hydrolysis temperature or even the pressing time and pressure. Once the agglomerates had been obtained, they were tested in various physicalmechanical tests and the results were evaluated based on the requirements for insoles. The agglomerates with the best characteristics and results in the physical tests were those prepared with products made from pinewood resin. The physical tests and respective requirements performed were: tear strength equal to or higher than 15N, water absorption and desorption of 70 mg/cm2 and 60% respectively, 25600 cycles in the Martindale abrasion test without significant deterioration or discoloration, delamination resistance equal to or higher than 650 kPa and flexing index equal to or higher than 3,3. The best agglomerates produced presented the following results: 19N in the tear resistance test, an absorption of 69,9 mg/cm2 and a desorption of 76,7%, an abrasion test with no evidence of deterioration, color change, or significant reduction in thickness, a delamination resistance of 64,1 kPa and a flexing index equal to 1,1. To summarize, at this stage it can be concluded that none of the produced agglomerates is ready to suffer the action and tear to which an insole is subjected, demonstrating an internal cohesion and repeated bending movement resistance that is still insufficient for the intended application.
Description
Keywords
Resíduos de couro Aglomerados Palmilhas Indústria do calçado Leather waste Agglomerates Insoles Footwear industry