Universal plant to produce mix
of grades of polystyrene plastics
by continuous bulk polymerization

Plastpolymer Joint Stock Holding Company has vast experience in the sphere of R&D of the production of wide mix of grades of plastics and in the sphere of designing pilot and commercial plants to produce polystyrene plastics by polymerization in bulk, suspension and emulsion as well as to produce compounds on their basis.

During last 30 years experts of Plastpolymer have created 16 plants for polystyrene plastics in the former USSR.

In 1994 within the frames of the Indian-Russian enterprise a plant was commercialized in India to produce high impact polystyrene and ABS by continuous bulk polymerization, 20 000 MTA, on the basis of the process and project documentation of Plastpolymer. The plant operates successfully and produces impact polystyrene, general purpose polystyrene, ABS and SAN with the properties of the products relevant to those produced by modern foreign companies.

The equipment and process flow sheet of this continuous bulk polymerization process and further removal of non-polymerized monomer and solvent is simple, reliable, flexible, universal and can be fully automatic, in other words it can be controlled by computer system.

Its utility consumption and cost are on the up-to-date world level for the processes for impact polystyrene (UPM), general purpose polystyrene (PSM), ABS and SAN.

On Buyer's option the line can be designed for 50 - 100 000 MTA.

The process is pure and has high level of mechanization and automation.

Wide mix of base grades (UPM, PSM, ABS and SAN) is produced, their properties are on the level of best foreign counterparts.

On Buyer's option production of special grades can be proposed on separate extrusion lines.

Bulk polymerization process includes the following basic stages:

• preparation of raw materials and chemicals;
• polymerization in cascade of reactors;
• removal of non-reacted monomers and solvent;
• primary granulation and compounding (if necessary);
• bagging and storage of the finished products;
• recovery of monomers and solvent;
• preparation of the heating agent and its supply to the process stages.

The principal process flow sheet for the universal plant to produce various types of polystyrene plastics is shown on the figure.

Preparation of raw materials includes rubber grinding and dissolving in monomers. When additives are charged rubber solution is pumped by metering pumps from make-up tank to polymerization.

Polymerization is carried out by 3 stages one after another. Reaction fluid is transported by dischargers.

Non-reacted monomers are removed by two stages in vacuum chambers.

Monomer and solvent vaporous are condensed, collected and supplied to treatment (recovery). Distillates obtained are recycled.

Polymer melt is transported from vacuum chamber to granulation. Compounding additives can be added to the melt at this stage.

Below you will find specifications and physico-mechanical properties of the mix of grades of polystyrene plastics, consumption data for raw materials, chemicals and utilities.

Approximate expenses for the plant are also shown in the appendix.