Process for the preparation of block copolymers
US4219627A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 9, 1977 |
| Grant date | Aug 26, 1980 |
| Priority date | — |
| Expiry date | Mar 9, 1997 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G81/022
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The process described herein involves the preparation of block copolymers of the S-B-S type wherein S represents a block of polystyrene and B represents a block of polybutadiene. In order to have the initial polystyrene block soluble in the polymerization medium, cyclohexane and aromatic hydrocarbons have been used as the diluent or solvent in these polymerizations. The present process permits the use of hexane as diluent by having dissolved therein prior to polymerization a small amount of the S-B-S type of block copolymer being produced in the polymerization. Advantageously this solution used as the polymerization medium is prepared merely by washing the reactor used in a previous polymerization for production of the same type of S-B-S block copolymer with hexane to dissolve solid residues of S-B-S block copolymer deposited on the wall or agitator of the reactor. This hexane solution is then retained in the reactor to serve as the medium for the next polymerization batch. The dissolved S-B-S copolymer serves as a suspension agent for dispersion of the initial polystyrene block.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.