Method for producing polylaurolactam powder compositions for the coating of metals at high temperatues
US4195162A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 13, 1978 |
| Grant date | Mar 25, 1980 |
| Priority date | — |
| Expiry date | Jul 13, 1998 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2377/02
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Polylaurolactam powder coating compositions for the coating of metals at high temperatures are obtained by grinding low molecular weight and brittle polylaurolactam with subsequent condensation by heating of the powder to temperatures of below its melting point. A. For the production of pigment free polylaurolactam powders, the low molecular weight granules are ground at temperatures of between 0.degree. and 45.degree. C. which have a relative viscosity of between 1.25 and 1.45 (measured in a 0.5 percent mecresol solution at 25.degree. C.) and have been produced by the polymerization of laurolactam in the presence of 2-10 percent by weight of water, 0.3-0.7 percent by weight of phosphoric acid at temperatures of between 265.degree. and 300.degree. C. in the absence of chain stabilizers under internal pressure, with subsequent granulating, and extraction between 25.degree. and 70.degree. C. with methanol or ethanol. The subsequent condensation is conducted at temperatures of between 140.degree. C. and below the melting point of the polyamide to relative viscosity value of between 1.55 and 1.65; and finally the powders obtained are brought to a particle size distribution of between g…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.