ABS resins having impact resistance and low-gloss properties and processes for preparing them

Abstract

The present invention relates to ABS (Acrylonitrile-Butadiene-Styrene) resins having excellent impact resistance, low-gloss properties and superior heat resistance, and to a process for preparing them. In particular, between 5 wt % and 20 wt % butadiene rubber having double bonds is dissolved in between 30 wt % and 70 wt % graft-copolymerizing aromatic vinyl monomer and between 10 wt % and 50 wt % cyanized vinyl monomer. Polymerization controller and radical initiator are added to the above, and the mixture polymerized in a first step of bulk polymerization at a temperature of 80.degree.-120.degree. C. while stirring until polymerization proceeds to between 20 and 50% of completion. Between 40% and 70% .alpha.-methyl styrene monomer, between 10 wt % and 40 wt % unsaturated nitrile and between 5 wt % and 15 wt % butadiene rubber are then added to the polymerized mixture and the resulting mixture stirred for 30-60 minutes in a second step of bulk polymerization. Finally, distilled water and a suspending agent are added to disperse the mixture, which is then polymerized with a radical catalyst in a final step of suspension polymerization.

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