Ethylene → Ethylene styrene

Participants

Reaction Steps

The polymer is prepared in a 400 gallon (1514 liter) agitated semi-continuous batch reactor. The reaction mixture consists of about 250 gallons (946 liter) of styrene and a solvent comprising a mixture of cyclohexane (85 weight percent) and isopentane (15 weight percent). Prior to addition, solvent, styrene and ethylene are purified to remove water and oxygen. The inhibitor in the styrene is also removed. Inerts are removed by purging the vessel with ethylene. The vessel is then pressure controlled to a set point with ethylene. Hydrogen is added to control molecular weight. The temperature in the. vessel is controlled to set-point by varying the jacket water temperature on the vessel. Prior to polymerization, the vessel is heated to the desired run temperature and the catalyst components, i.e. (tert-butylamido)dimethyl(tetramethyl-η5-cyclopentadienyl)silane 5dimethyltitatium(IV) catalyst, CAS# 135072-62-7, Tris(pentafluorophenyl)boron, CAS# 001109-15-5, Modified methylaluminoxane Type 3A, CAS# 146905-79-5, are flow controlled, on a mole ratio basis of 1/3/5 respectively, combined and added to the vessel. After starting, the polymerization is allowed to proceed with ethylene supplied to the reactor as required to maintain vessel pressure. In some cases, hydrogen is added to the headspace of the reactor to maintain a mole ratio with respect to the ethylene concentration. At the end of the run, the catalyst flow is stopped, ethylene is removed from the reactor, about 1000 ppm of Irganox™ 1010 anti-oxidant is then added to the solution and the polymer is isolated from the solution. The resulting polymers are isolated from solution by stripping with steam in a vessel. In the case of the steam stripped material, additional processing is required in extruder like equipment to reduce residual moisture and any unreacted styrene.

Provenance & Evidence