Otimização do processo de injeção de cabedais monocolores em policloreto de vinila (PVC). Estudo de caso: a indústria calçadista.

Abstract

The high recyclability of plastic materials has increasingly driven the formation of recycledbased products, which has become an eco-sustainable and cost-effective alternative for companies use plastics as now materials. This work aims at investigating the monochromatic uppers injection process in PVC, at an footwear industry, produced from the addition of recycled mixture through the conventional process (direct injection in horizontal machine), in order to obtain the best parameter for a specific model, focusing on obtaining pieces with similar quality and mechanical properties to those injected with virgin PVC. In the methodological part, numerical simulation tools (CFD), experimental techniques and (not standardized) mechanical tests (hardness test, optical microcopy, tension) were used. It was observed that for the focused model, parameters such as material temperature, pressure (injection, discharge and counter pressure) and mass flow rate of injection in the mold, led to interference and problems in molding the parts, resulting in products with low quality. Simulations using software confirmed the results obtained from the experiments generated by the experimental matrix, showing the ideal parameters to produce the modelselected, at the same operational conditions. The performed tests revealed that the mechanical properties were little affected by the addition of recycled material, making possible the production of monochromatic (black) uppers in industrial scale, using reprocessed material (1 cycle) with no significant changes of mechanical, visual and comfort features of the product.