Production of petroleum polymer resins

Abstract

In other countries, petroleum polymer resins are being used successfully in large volumes. In the U.S. in 1982, for example, 128,000 tonnes of petroleum polymer resins were produced [2], much of which was used in the paint and varnish industry. In commercial production in the USSR are a dark-colored styrene-lndene resin and light-colored petroleum polymer resins of two types -- SPP and Piroplast-2. The raw material for the production of the dark styreneindene resin is heavy pyrolysis tar (HPT), which is a residue from the distillation of liquid byproducts obtained in pyrolysis (cut distilling above 190~ A flow plan for the continuous production of styrene--indene resin is shown in Fig. i. The heavy pyrolysis tar is pumped to the furnace i, where it is heated to 240-300~ and then directed to the vacuum stripping tower 2 (residual pressure no higher than 27-10 -s MPa). Superheated steam is fed to the bottom of the tower. The vaporized light hydrocarbons leaving the top of the tower at 250-280~ pass into the cooler 7, where they are condensed and then flow by gravity into theseparator 8. Part of the condensate is fed to the tower top as reflux, and the balance excess is withdrawn from the unit for subsequent processing. A styrene--indene resin distillate is drawn from tower 2 as a sidestream, through the cooler 10 into the tank Ii; this product is used as a feedstock for carbon black manufacture. The resin from the bottom of tower 2 passes to the ribbon cooler 4, from which it passes in the form of flakes through the hopper 5 and then to the packaging operation. The yield of sytrene--indene resin relative to the original feed is 27.8%, The quality indexes of this product are as follows: softening point 89~ ash 0.08%, moisture 0.12%, total sulfur 0.16%, no solid impurities as determined by visual examination, acidity or basicity 0.008% (as HCI or NaOH). The finished product is in flake form, with a flake thickness up to 3 ~m~. The styrene-indene resin has a dark color; it contains highly polymerized hydrocarbons of the coke inclusion type, which are difficult to dissolve not only in nontoxic aliphatic solvents, but even in aromatic solvents. This restricts the field of application of the styrene--indene resin| it is used almost exclusively as a softening agent in tire rubber mixes. The feedstock used in producing light-colored PPR is a 120-190~ cut from pyrolysis products, containing unsaturated hydrocarbons (styrene, ~-methylstyrene, vinyltoluenes, dicyclopentadiene, indene, and others). The Grade SPP resin is obtained by initiated polymerization of the feed using isopropylbenzene hydroperoxide as an initiator. The Piroplast-2 is produced by thermal polymerization of the feed. A simplified flow plan for the production of the SPP resin is shown in Fig. 2. The feed from the tank is pumped through the preheater 1 and a cascade of series-connected polymerizers 2-5. "Gipergiz" [isopropylbenzene is also fed continuously. The polymerization is performed at a temperature up to 200~ and a pressure of 0.15-0.6 MPa for a period of 10.5-12 h. The polymerizate from the polymerizer 5 is fed to the preheater 6 and then to the stripping tower 7 for separation of the PPR. The hydrocarbon vapors and water pass from the top of the colum~ to the separator. The upper organic layer is directed to a sol ~