The flow characteristics of synthetic rubbery polymers are important for a variety of reasons including the ability to mold by injection such polymers and the distortion of packages of such polymers. Of primary, but not the only, concern in the present injection is the flow of polymers during storage in packages, commonly referred to as cold flow. If a polymer has a high tendency to cold flow the package containing such a polymer will become distorted over time causing the handling of such a package to be difficult. If there is a desire to fracture bales of polymer into small particles, those polymers having a high tendency to cold flow are more difficult to handle.
Accordingly, there is a need to be able to readily determine the flow characteristics of synthetic rubbery polymers. In the past this has been achieved by the very simple method of placing a cube or a plug of the polymer on a surface which is inclined at 30.degree. or 40.degree. to the horizontal and measuring the extent of flow down the surface. The method using the apparatus of this invention is faster, easier, more controllable, more accurate and readily reproducible.