Technical parameters of LLDPE

Most of the processes applied for the production of polypropylene are very similar to the ones used to produce high density polyethylene. Nevertheless, this section describes the most important and most widely used processes for the production of polypropylene. Generally, two different types of processes are apphed in the production of polypropylene  

The traditional suspension processes using an organic diluent, are known within the PP nomenclature as slurry processes. Modem suspension processes use a liquid monomer instead of a solvent. And they are known in the PP world as bulk processes. 

The further development of the catalysts used for polypropylene synthesis had far-reaching consequences for process development. Due to the development of new processes based on the possibilities offered by the new catalysts and the changing range of properties of polymers, the development of catalysts for polypropylene synthesis will be briefly described  

These catalysts were first introduced in the 1960s in slurry processes. The active centres of these catalysts are located at points of missing chlorine atoms in TiCls crystals. These catalysts have low yields (1 t/kg catalyst), produce 5 to 10 % atactic polypropylene and require de-ashing and atactic removal from the final product 

These have been in use since the 1970s in suspension and gas phase processes, and their yields are around 10 t/kg catalyst. De-ashing is still required and the content of atactic product 

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