Published October 1969
This report is a supplement to Process Economics Program Report No, 19, Linear Polyethylene and Polypropylene," November 1966. In Report No. 19, two processes were evaluated for production of linear polyethylene. The first process utilized a Ziegler catalyst under conditions that produced a polymer slurry, and the second utilized a metal oxide catalyst under conditions that produced a polymer solution. Polypropylene was evaluated by analogy with the polyethylene process utilizing a Ziegler catalyst. All three evaluations were made at a production level of 60 million lb/year. In this supplement, a third process for linear polyethylene has been evaluated, based mainly on information and patents that have appeared since the previous report. This process utilizes a metal oxide catalyst to produce the polymer in particle form. The evaluation was made at a production level of 60 million lb/yr to permit direct comparison with the previous evaluations, the costs of which have been updated. Production costs at 30 million and 120 million lb/yr have also been estimated.
Polypropylene has been evaluated on the basis of a new, detailed process design at a production level of 120 million lb/year. This higher capacity was chosen because it is more in line with the sizes of recently announced new plants and expansions for polypropylene manufacture. Production costs at 60 million and 240 million lb/yr have also been estimated.
Of the various applications of polypropylene, molding is the largest single use, amounting to 50%. The use of polypropylene in fiber form is the fastest growing, however, and an examination of the economics is of interest. Accordingly, an evaluation was made of the manufacture of polypropylene fiber as continuous filament yarn of 165 denier and 840 denier.
