Polypropylene Resin

Solvent Polymerization and Solution Polymerization Method

Solvent Polymerization Method

The solvent method (also known as slurry method or slurry method, slurry method) was the first polypropylene production process used, but due to the shortcomings of the de-ashing and solvent recovery process, long process, more complex, etc., with the progress of catalyst research technology, from the eighties, the solvent method has tended to stagnate, gradually replaced by the liquid phase principal method.

Process characteristics:

(1) Propylene monomer dissolved in inert liquid-phase solvent (such as hexane), solvent polymerization under the action of catalyst, polymer in solid particles suspended in the solvent, using kettle-type stirring reactor.

(2) There are de-ash and solvent recovery process, long process, more complex, large investment in the device, high energy consumption. However, the production is easy to control and the product quality is good.

(3) The polypropylene particles are separated by centrifugal filtration and then dried by air boiling and extrusion granulation.

Solution Polymerization Method

Process characteristics:

(1) Using high boiling point straight chain hydrocarbons as solvent, operating at a temperature higher than the melting point of Polypropylene Resin, the resulting polymer is all dissolved in the solvent in a homogeneous distribution.

(2) High-temperature gas extraction method to evaporate and remove the solvent to obtain molten Polypropylene Resin, and then extrusion granulation to obtain granular products.