Moulding Technics Study And Mould Design Of Polyurethane Foams

Rigid polyurethane plastic foam, with advantages as relative low density, specific strength, thermal conductivity, and easy to combine with other components and simple composite forming, is widely used on structural component area. Especially reinforced polyurethane plastic foam, combing features of polyurethane plastic foam and polyurethane rubber, can resist impact and shock, has important application value to industrial and national defense.For the variety of raw material and formulation of polyurethane, notable differences exist among process technology and parameters to various polyurethane plastic foam. Different process technologies will influence mechanic property significantly.After investigating lots of correlative literature, a set of visible foaming process inspecting system was designed to collect and analyze the data, the pressure and temperature change during the foam formation were monitored. The effects of component ratios and technics parameters during water-foaming moulding process of the filling enhanced polyurethane foams on the technics properties were studied. The effects of the component ratios and mould temperature on the foaming pressure and highest temperature of the foaming center, and the relationships between the foaming contractility and foaming pressure and the densities were all obtained. By researching the viscosity changes of the reaction system after adding the fillings, and analyzing the properties of polyurethane foams when applying reaction injection moulding method and enhanced reaction injection moulding method into enhanced polyurethane foam structure product, a moulding technics that could obtain the best mechanical properties was found out.Mould material, moulding accessories, cast systems, exhausting and sealing structure, demould device, foaming pressure controlling systems were analyzed partly. The working measurement calculating method of the moulding accessories and the mechanics calculating basis of the cavum structure were acquired by analyzing designmethod.In order to increasing the properties, guaranteeing the technics stability and shortening the exploitation term of new products, the technics and the moulds of enhanced polyurethane foams were analyzed and designed.