Continuous production of polycaprolactam having a regulated amino end group content
US5149758A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 11, 1991 |
| Grant date | Sep 22, 1992 |
| Priority date | — |
| Expiry date | Jun 11, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G69/16
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Polycaprolactam having a regulated amino end group content is produced in a continuous process in which caprolactam is polymerized at 240.degree.-290.degree. C. in the presence of water as initiator and in the presence of a dicarboxylic acid as chain regulator by polymerizing caprolactam in a single stage in the presence of from 0.3 to 5% by weight of water and from 0.1 to 0.6% by weight of terephthalic acid and/or isophthalic acid, each percentage being based on caprolactam, at a uniform pressure through the entire polymerization time of from 1.0 to 1.9 bar, measured in the vapor phase above the polymerization zone, while maintaining a water content of from 0.1 to 0.5% by weight, until the sum total of the amino and carboxyl end group contents is from 115 to 150 meq/kg, with the proviso that the amino end group content does not drop below 25 meq/kg, measured on extracted polycaprolactam.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.