Powdered rubber-filler batches
Adam Tarniowy, Eulalia Grabowska Ośrodek Badawczo-Rozwojowy Kauczuków i Tworzyw Winylowych, ul. Chemików 1, 32-600 Oświęcim
Annals 2 No. 4, 2002 pages 204-207
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abstract The multi-stage compounding process is the state of the art in the rubber industry. The main reason for this complicated stage compounding process is the necessity to incorporate the filler into the rubber phase which is energy and time consuming. The application of powdered rubber-filler batches is one of the most promising way to simplification of manufacture of rubber compounds in the rubber industry. The manufacture of the powdered rubber-filler batches is explained by means of a flow diagram (Fig. 1). The first step is to produce a filler aqueous dispersion. In the next step, prepared filler dispersion is introduced into polymer latex. Sometimes the filler is introduced directly into latex. The latex emulsion and filler dispersion are homogenised (under continuous stirring) and precipitated (coagulated). In this work carbon black and silica were used as a filler. These fillers were introduced into nitrile rubber latex. Morphology of obtained powdered ruber/filler batches were studied by scanning electron microscopy (SEM) (Figs 2-5). The product consisting of nitrile rubber and incorporated carbon black (50 phr) is in a free flowing powder form (Fig. 2). A deterioration in the homogeneity and free flow property of the silica filler contents batch (Figs 4, 5) is observed. To check the technological properties of rubber powder containing 50 phr carbon black two rubber compounds were made (Table 1), the first (K-I) in traditional way and the second (K-II) by means of powdered rubber. The use of powdered rubber batch leads to shorter mixing time - 8 min 30 s (mixing time of traditional prepared rubber compound is equal to 23 min). These two compounds were cured. The mechanical tests of obtained vulcanizates were made with Instron tensile testing machine. There is no significant differences between mechanical properties of obtained vulcanizates.