Claims
- 1. A process for preparing a syndiotactic polypropylene comprising washing, at a temperature of from about 0.degree. C. to about 100.degree. C., with a hydrocarbon solvent of propylene, propane, butane, pentane, hexane, heptane, octane, nonane, benzene, toluene, xylene, ethylbenzene, or said hydrocarbons in which at least one of the hydrogen atoms thereof is substituted with halogen, a polymer obtained by polymerizing propylene in the presence of a catalyst comprising a transition metal compound having an asymmetric ligand, wherein the syndiotactic polypropylene of said polymer is insoluble in said hydrocarbon solvent and the non-syndiotactic polypropylene of said polymer is soluble in said hydrocarbon solvent and wherein said washing further comprises separating the solvent insoluble polymer from the solvent soluble polymer, so as to remove a surface polymer of low-tacticity or low-molecular weight from said syndiotactic polypropylene.
- 2. The process according to claim 1 wherein said catalyst comprises said transition metal compound and an aluminoxane.
- 3. The process according to claim l wherein prior to the washing with a hydrocarbon solvent, the polymer is treated with a .beta.-dicarboxy compound represented by the general formula ##STR3## wherein R.sup.1 and R.sup.2 are individually a hydrocarbon residue having 1-12 carbon atoms and an alcohol under non-aqueous conditions.
- 4. The process according to claim 1 wherein prior to the washing with a hydrocarbon solvent, the polymer is treated with an alcohol containing hydrochloric acid gas under non-aqueous conditions.
- 5. The process according to claim 3 wherein subsequent to the treatment with a .beta.-dicarboxy compound and an alcohol and prior to the washing with a hydrocarbon solvent, the polymer is washed with water under acidic conditions.
- 6. The process according to claim 4 wherein subsequent to the treatment with an alcohol containing hydrochloric acid gas and prior to the washing with a hydrocarbon solvent, the polymer is washed with water under acidic conditions.
- 7. The process according to claim 1, wherein said hydrocarbon solvent is toluene, 1, 2-dichloroethane, hexane or propylene.
Priority Claims (4)
Number |
Date |
Country |
Kind |
1-89721 |
Apr 1989 |
JPX |
|
1-89722 |
Apr 1989 |
JPX |
|
1-224675 |
Sep 1989 |
JPX |
|
2-29473 |
Feb 1990 |
JPX |
|
Parent Case Info
This application is a continuation of application Ser. No. 08/100,190 filed Aug. 2, 1993, now abandoned, which is a continuation of application Ser. No. 07/613,694, filed Nov. 27, 1990.
US Referenced Citations (10)
Foreign Referenced Citations (3)
Number |
Date |
Country |
0299391 |
Jan 1989 |
EPX |
WO8805792 |
Aug 1988 |
WOX |
WO8805793 |
Aug 1988 |
WOX |
Non-Patent Literature Citations (1)
Entry |
J. Am. Chem. Soc. 1988 110, pp. 6255-6256 (J. A. Ewen). |
Continuations (2)
|
Number |
Date |
Country |
Parent |
100190 |
Aug 1993 |
|
Parent |
613694 |
Nov 1990 |
|