How is Polypropylene Production Made?
Polypropylene was first produced in 1954. Since then, many polypropylene production methods have been developed and started to be produced in different methods. Polypropylene production is very important in order to meet the raw material needs. It is only possible to meet the increasing need for raw materials by increasing production.
The need for raw materials such as polypropylene is increasing every year. Especially since this polymer is used in many sectors, it is a much needed substance. It is among the most used plastic raw materials. This raw material is also used in the production of many products that we use in our daily lives. The production of this raw material, which is widely used, is also becoming more and more widespread.
Polypropylene is a substance produced using three different ways: gas phase, bulk phase and slurry phase processes. Gas phase and bulk phase processes are more economical and more popular as they were developed later than the slurry phase process method.
Gas Phase Polypropylene Production
It provides semi-crystalline polypropylene as a result of polymerization of gaseous monomers with the catalytic effect created by high-activity catalysts. The process consists of the following parts:
1) Monomer Purification: Since compounds containing water and oxygen and containing sulfur in monomers will cause catalyst poisoning, such compounds are purified at the optimum level in monomer purification units.
2)Catalyst Loading: The catalysts are given to the reactor from the catalyst loading drum. The number of catalysts is adjusted according to the production capacity and the type of production.
3) Polymerization Reactor: There are 2 reactors in continuous mixing and a fluidized bed. One end of these reactors is used to load monomer materials and catalyst, while the other end is used to obtain polymers in powder form. The reactors are designed with low pressure for continuous production of polypropylene powders.
4) Separation of Powdered Products: The polymer and gas mixture passing through the reactor is sent to the gas-powder separation unit to be separated from each other. After the gas and powder mixture is separated from each other, the gas part is pressurized and sent back to the reactor section. The powder part, on the other hand, is sent to the powder product palletizing unit after being subjected to catalyst deactivation and gas steaming in the final degassing column.
5) Shaping the Product: After being brought to the powdered polypropylene packaging unit, it is mixed with a masterbatch containing additives to bring it to the desired properties. Then the mixture is melted and granulated by giving it to the extruder. It is then placed on the market.
Bulk Phase Polypropylene Production
1) Monomer purification: Since the impurity of ethylene, heptane and nitrogen monomers causes catalyst poisoning, monomers are brought to polymer purity.
2) Catalyst and cocatalyst preparation: The catalysts used are diluted in heptane and become ready.
3) Preparation of additives: In order to give the desired properties to the polymer, mixtures suitable for the polymer are prepared with additives and then given to the process during the granulation phase.
4) Polymerization: There are reactors with two control systems in accordance with the polymerization process. Depending on the type of polymer and the flow rate of the reactor, monomers are given. Only 20% of the given monomer can be purified in the recovery unit and returned to the reactor. Powdered polymers are separated from unreacted monomers in a degassing unit.
5) Extrusion: Polypropylene in powder form is stored in powder silos after final degassing. Then, powder separation is started with the help of weighing scale. Various chemicals are added according to the type of polypropane. Granulated and marketed