Verfahren zur Verminderung des Kaltfliessens von kautschukartigem Polybutadien

摘要

Cold flow in polybutadiene containing at least 40% cis-1-4 configuration is reduced by masticating the raw, uncompounded polybutadiene for 2-30 minutes at 240-460 DEG F. while limiting the available oxygen to the polymer so that the inherent viscosity of the polybutadiene does not decrease by more than 0.85%. The mastication is preferably such as to produce high shear while excluding oxygen and such that the maximum velocity gradient is at least 150 reciprocal seconds. In a modification polybutadiene containing at least 75% cis-1-4 configuration is masticated in the presence of oxygen under high shear conditions in which the maximum velocity gradient is at least 200 reciprocal seconds and which will produce a 3-minute product temperature of at least 275 DEG F. The product may be mixed with the usual compositing ingredients and cured.