Published October 1970
This report is a supplement to Process Economics Program Report No. 4 issued in April 1965. Ethylene-propylene co- and terpolymers are amorphous, random, rubbery polymers resulting from polymerization of the monomers using Ziegler-Natta catalysts. In Report No. 4, processes for both co- and terpolymer production were evaluated. Since that time, industrial interest in the copolymer (EPM for ethylene-propylene-polymethylene) is relatively less because of the limitations imposed by the unconventional (peroxide) cure system, and efforts have been concentrated on developing the sulfur-vulcanizable terpolymers. The terpolymers, designated EPDM for ethylene-propylene-dene-polymethylene rubber, are proving useful in steadily expanding fields of application. This supplement is thus directed primarily toward terpolymer processes and applications.
In the current report four processes are evaluated. Two of them are for polymer synthesis, and two are for polymer extension and reinforcement. The synthesis processes are designed on the basis of producing an ethylene-propylene-ethylidene norbornene terpolymer. In the first synthesis process the polymer remains in solution. Solution processes appear to be used by the majority of EPDM producers. In the second process, the polymer precipitates as fast as it forms, resulting in a suspension. Montecatini has announced that it employs a suspension process. EPDM has the ability to accept unusually high loadings of extending oils and reinforcing fillers. The costs of extending and reinforcing EPDM have been examined for two processes, one using solution master-batching and the other using the Banbury internal mixer.
