Method of degassing polymers prepared by mass polymerizing a monomeric composition based on vinyl chloride
US4217444A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 16, 1978 |
| Grant date | Aug 12, 1980 |
| Priority date | — |
| Expiry date | Feb 16, 1998 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F6/005
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
An improved method of degassing polymers and copolymers prepared by mass polymerizing a monomeric composition, based on vinyl chloride. The polymer is kept under agitation, the monomeric composition to be eliminated is brought from polymerization pressure to a pressure below 120 mm of mercury, the polymer is brought to or kept at a temperature of at least 70.degree. C. and below the temperature at which degradation of the polymer or copolymer commences, and these conditions of pressure and temperature are maintained substantially until the degassing process stops, the polymer being put into contact with a quantity of water representing 0.01 to 0.8% and preferably 0.05 to 0.5% of its weight, after the residual monomeric vinyl chloride content of the polymer or copolymer has been reduced below 2000 ppm. The polymers and copolymers obtained, before being placed in open air, have a residual monomeric vinyl chloride content which is less than 50 ppm, generally less than 20 ppm and may be as little as 1 ppm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.