Location: RER - Europe
The dataset represents the production mix of commercial E-PVC production technologies
Polyvinyl chloride (PVC) is manufactured by polymerisation of vinyl chloride monomer (VCM). Polymerisation of PVC is an exothermic reaction. The pressure in the reactor is usually in the range of 0.4 – 1.2 MPa and the reaction temperature is between 35 – 70°C. During the polymerisation reaction 85 – 97% of the VCM is converted into PVC. Residual VCM is removed by stripping the polymer suspension or latex. The unreacted monomer is recovered, liquefied, and returned to polymerisation
For the polymerisation process certain process chemicals are required. Surfactants, emulsifiers and protective colloids are used to prepare and stabilize the dispersion of monomer and PVC in process water (typically around 1 kg/t VCM in suspension and around 10-20 kg/t in emulsion). Organic peroxides or peresters are used as initiators (typically < 1 kg/t VCM) for the production of suspension and microsuspension PVC, while e.g. hindered phenols are used to stop the reaction (typically < 1 kg/t VCM). For the production of emulsion PVC inorganic peroxides are common.
The mean particle size of E-PVC, polyvinyl chloride polymerised in emulsion process, is about 0.1 – 3 μm. E-PVC is mainly manufactured via one of three polymerisation processes: batch emulsion, continuous emulsion and microsuspension. Depending on the process used, the mean particle size of the E-PVC can be adjusted, affecting the product properties and application possibilities. Regarding paste or plastisol polymer properties, e.g., the PVC particle size distribution achieved during the polymerisation process will largely determine the rheology of the plastisol, when the polymer is redispersed in plasticiser. In the batch emulsion process, the emulsifier used is usually a sodium alkyl, aryl sulphonate, or alkyl sulphate. The polymerisation takes place in the VCM-water boundary layer, supported by a water-soluble initiator such as alkali metal persulphate. A redox system involving traces of copper and a reduction agent is often used. This reaction system produces small and narrow width unimodal PVC particles (approximately 0.2 μm). Using seed particles allows them to grow while new particles are forming simultaneously, resulting in a bimodal particle size distribution.
Undefined unit processes (UPRs) are the unlinked, multi-product activity datasets that form the basis for all of the system models available in the ecoinvent database. This is the way the datasets are obtained and entered into the database by the data providers. These activity datasets are useful for investigating the environmental impacts of a specific activity (gate-to-gate), without regard to its upstream or downstream impacts.