Luperox® for Polymerization of Vinyl Chloride
Luperox® organic peroxides boost productivity of vinyl chloride polymerization.
Arkema Luperstop® and Term-N-Ator® shortstoppers can add control to your polymerization reaction.
A Range of Solutions
The wide range of Luperox® organic peroxides is well adapted to suspension process for polymerizations of vinyl chloride. The reaction is generally performed between 40 and 80°C over 3 to 10 hours. The molecular weight and density of the polymer can be regulated by temperature in the reactor. Temperature is constant during polymerization for a given grade, for example, K-67 is typically manufactured at 57°C.
Suspension polymerization represents a large majority of worldwide polyvinyl chloride production. The main characteristics of this process are:
- Batch technology
- Reaction in water, liquid vinyl chloride in droplets of lower than 50 µm
- Autoclave reactor: 8-12 bars, 50 - 70°C
- Polymerization conducted up to 75% conversion
- Reaction finished or stopped at about 90% conversion
Increased productivity in vinyl chloride polymerization is achieved when the thermal energy generated by peroxide decomposition is as constant as possible. For this reason, a selection of several peroxides is recommended:
- A high activity, short half-life peroxide to quickly start the reaction
- A medium half-life peroxide to continue the reaction
- A long half-life peroxide to achieve good monomer conversion
|Half-Life (°C)||Peroxide Recommended||K Value||Reaction Temperature (°C)||Application|
||≥ 70||< 54||Flexibles|
||≥ 62||> 60||Rigid Film/Sheet|
Emulsions of peroxide in water offer unique advantages:
- Water in the formulation acts as a heat-sink, reducing risk of ignition
- Fish-eyes in the resins can be reduced
- Faster dispersion in the reactor
- Improvements in waste water treatment
Arkema is offering a range of emulsions to the PVC industry.
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