Patent EA-000521-B1 (EA)
Title: Process for making propylene homo or copolymers
Inventor: ANDTSJOE HENRIK
IPC: C08F2/00
Filed: 1996-10-10
Abstract: 1. A process for making homo- or copolymerizing propylene comprising: homo- or polymerizing propylene in the presence of a catalyst in at least one continuous stirred type reactor or loop reactor at a temperature and pressure above the corresponding critical temperature and pressure of the reaction medium for at least 15 minutes to form the propylene polymer or copolymer particles. 2. The process according to Claim 1, wherein said polymerizing is carried out under supercritical conditions at a temperature above 92 degree C and at a pressure above 46 bar. 3. The process according to Claim 1 or 2, wherein the reaction medium contains 0.001-100 mol hydrogen/kmol of propylene. 4. The process according to Claim 1 or 2, comprising carrying out polymerizing in two loop reactors, wherein a first polymerizing step is carried out at a subcritical temperature in a first loop reactor; and a second polymerizing step is carried out under supercritical temperature and pressure in a second loop reactor. 5. The process according to Claim 4, wherein the polymerizing temperature in the first loop reactor is 50-80 degree C and the polymerizing temperature and pressure in the second loop reactor are 92-110 degree C and 46-80 bar. 6. The process according to Claim 4, comprising feeding hydrogen at a concentration of 0-15 mol/kmol of propylene into the first loop reactor, and feeding hydrogen at a concentration of 0.001-100 mol/kmol of propylene into the second loop reactor. 7. The process according to Claim 4, comprising adding hydrogen only to the second loop reactor. 8. The process according to Claim 1 or 2, comprising carrying out two polymerizing steps both under supercritical conditions at a temperature above 92 degree C and at a pressure above 46 bar. 9. The process according to Claims 1 or 2, comprising conducting a first polymerizing step in a loop reactor under supercritical conditions at a temperature above 92 degree C and at a pressure above 46 bar; optionally at least partially removing the polymerization medium from the resulting polymer; feeding the resulting polymer into a gas phase reactor; and conducting a second polymerizing step in said gas phase reactor. 10. The process according to Claim 9, wherein the temperature and pressure in the gas phase reactor are 60-100 degree C and 10-40 bar. 11. The process according to Claim 1, wherein the catalyst comprises magnesium dichloride, a titanium compound, and a transesterification reaction product of a lower alcohol and an ester of phthalic acid. 12. The process according to Claim 11, wherein the lower alcohol is methanol or ethanol, the ester of phthalic acid is dialkylphthalate where the alkyl group comprises at least five carbon atoms, and transesterification is carried out at a temperature of 110-150 degree C. 13. The process according to Claim 12, wherein the components of the catalyst are precontacted before feeding into said reaction medium. 14. The process according to Claim 11, wherein the catalyst is prepolymerized with propylene at a temperature of 20-80 degree C before feeding into the reactor. 15. The process according to Claim 1, wherein said comonomers are ethylene or butylene. 16. The process according to Claim 1, comprising adding up to 20% of methane or ethane to said reaction mixture. 17. The process according to Claim 1, comprising carrying out polymerization in the presence of a metallocene catalyst. 18. The process according to Claim 6, comprising feeding hydrogen into the first loop reactor at a concentration of 0-3 mol/kmol per mol of propylene. 19. The process according to Claim 6, comprising feeding hydrogen into the second loop reactor at a concentration of 1.5-15 rnol per mol of propylene. 20. The process according to Claim 5, comprising feeding hydrogen only into the loop reactor operating under supercritical conditions. 21. The process according to Claim 5, comprising feeding hydrogen at a concentration of 0-15 mol/kmol of propylene into the first loop reactor, and feeding hydrogen at a concentration of 0.001-100 mol/kmol of propylene into the second loop reactor.