Abstract.Flow conditions are different in the cavity of the injection mould from the capillary flow of a laboratory rheological instrument. An injection moulding slit die rheometer (Rheo-mould) was designed with a series of slit and orifice dies. Four pressure sensors were built in the stationary side of the mould, therefore the pressure could be measured at four different places. A changeable slit die insert was designed in the moving side. The shear stress and the shear rate can be calculated from the pressure gradient and from the flow rate of the melt, respectively. Flow curves of low density polyethylene were determined using Bagley, Rabinowitsch and Mooney corrections. The results were compared to the flow curves determined by Göttfert and Haake capillary equipments. It was found that the agreement between the methods is excellent.

A special capillary rheometer measuring instrument has been developed. Kistler hardware and LabView software were applied. Due to this automatic measuring system the measuring cycle time reduced and the accuracy of the results increased. By applying a quick-change capillary system, plastic materials flow properties can be determined. The effect of the mould temperature, the material temperature and the shear rate were investigated to the apparent viscosity. The viscosity is given by the power low, and the standard deviation was less then (R2=0,98). After the Bagley and Rabinowitsch corrections the results showed less than 5% differences compared with a standard HAAKE measuring instrument.

Nowadays it is very important to think about revering of accessories of cars those are taken out of circulation. At present around 80% of the car components have to be renewable according to regulations. It is remarkable that 10% of the accessories of motor vehicles are made of polymer. An average car is made of about 143 kg polymer. The most typical materials are LDPE, HDPE, PP ABS, PA, PVC, PC, POM, PBT. These basic commodities can be renewed after a long procedure. The problem is, these materials do not solved in each other, therefore some kind of separation is necessary. The produced blends will not have as good quality as the pure materials. The aim of our research is to examine the mechanical property of blends considering the concentration of basic commodities. We attempted to get more information about the attribution of plastic garbage and blends, thus we would be able to produce products.

The molten polymers are non-Newtonian materials because their viscosity apart from the temperature depends on the shear rate, pressure, the molecular weight, molecular weight distribution, flow geometry. The properties of the injection moulded part depend on the filling process. The goal of our research is to study the filling of the injection moulds. An instrumented injection mould was designed for the measurements. As against a standard injection mould, it has an open cavity so the material can flow out from the mould. Due to the technique, the filling time can be extended up to some seconds. The flow rate, in this manner the deformation rate, material and mould temperature was changed during the measurements. Due to the new technique, the cavity filling was studied and the pressure gradient was determined as function of process parameters. The flow properties were determined in wide shear rate range of the polyethylene (Tipolen FA 2210) material.