The effect of diehead design on fibre wetting in the Granex Process
August 15th, 1991
The third of three Prosyma Research Ltd reports to Santar on Granex, 6th December 1990, 5th June 1991 and 15th August 1991.
S F Bush
Summary
The SAFIRE long fibre reinforced pipe and sheet-making processes depend on the production of suitable long-fibre granules. The granules are used either in conjunction with virgin granules or on their own depending on the concentration of fibre required in the final product. Recently the granules have been applied to injection moulding.
For good final product it is apparent that each fibre should (a) be well-wetted by the polymer and (b) should retain a high proportion of its original length. The Granex process is designed to produce granules with these characteristics. This report concentrates on measuring characteristic (a) for a variety of Granex head designs. The last design in the series (Mk Va – March 1991) shows about 65% wetting which is a great improvement on the earliest results (10% – October 1988) though these low levels were not recognised at the time. Further improvements are in hand to raise the wetting level to 95% without increasing fibre breakage.