Patent GB-924462-A (GB)
Title: Process for the production of multilayer moulded articles having an outer layer of polyamide
Inventor: BRUEGGEMANN HORST
IPC: C08G69/18
Filed: 1961-09-07
Abstract: A process for the production of coated articles having an outer layer of polyamide by polymerization of lactams with an alkaline polymerization initiator and a polymerization activator comprises surrounding a shaped article composed of a material which is dimensionally stable at temperatures up to at least 300 DEG C. with a melt of one or more lactams with six to twelve carbon atoms containing an alkaline polymerization initiator and a substituted urea, thiourea or urethane as activator, and polymerizing the lactam. Specified lactams are S -caprolactam, oenanthic lactum, caprylic lactam, lauric lactam, 4-isopropyl-S -caprolactam and 3- methyl-S -caprolactam.  Specified initiators are alkali and alkaline earth metals and the oxides, hydrooxides, hydrides, carbonates, alcoholates and lactam salts thereof.  Suitable polymerization activators are disclosed in Specifications 900,150 and 900,151.  Cross-linking agents e.g. methylene-bis-caprolactam and fillers e.g. metal powder or graphite may be incorporated in the melt.  Specified core materials are iron, brass, aluminium and ceramics.  In the examples-(1) a shaped article preheated to 150 DEG C. is dipped into (a) a melt of caprylic lactam and sodium methylate and (b) a melt of caprylic lactam and bis-(caprylic lactam-N-carboxylic acid)-hexamethylene diamide-1:6 and suspended in a heating oven to complete polymerization and (2) sheet iron is preheated to 150 DEG C., dipped into a melt of S -caprolactam, caprylic lactam, potassium and bis-(caprolactam-N-carboxylic acid) hexamethylene diamide -1:6 and the lactams polymerized at 180 DEG C.ALSO:A process for the production of coated articles having an outer layer of polyamide by polymerization of lactams with an alkaline polymerization initiator and a polymerization activator comprises surrounding a shaped article composed of a material which is dimensionally stable at temperatures up to at least 300 DEG C. with a melt of one or more lactams with six to twelve carbon atoms containing an alkaline polymerization initiator and a substituted urea, thiourea or urethane as activator, and polymerizing the lactam.  Specified lactams are e -caprolactam, oenanthic lactam, caprylic lactam, lauric lactam, 4-isopropyl-e -caprolactam and 3-methyl-e -caprolactam.  Specified initiators are alkali and alkaline earth metals and the oxides, hydroxides, hydrides, carbonates, alcoholates and lactam salts thereof.  Suitable polymerization activators are disclosed in Specifications 900,150 and 900,151.  Cross-linking agents, e.g. methylene-bis-caprolactam and fillers, e.g. metal powder or graphite may be incorporated in the lactam melt.  Specified core materials are iron, brass, aluminium and ceramics.  In the examples:- (1) a shaped article preheated to 150 DEG C. is dipped into (a) a melt of caprylic lactam and sodium methylate and (b) caprylic lactam and bis-(caprylic lactam-N-carboxylic acid)-hexamethylene diamide-1:6 and suspended in a heating oven to complete polymerization and (2) sheet iron is preheated to 150 DEG C., dipped into a melt of e -caprolactam, caprylic lactam, potassium and bis-(caprolactam-N-carboxylic acid)-hexamethylene diamide-1:6 and the lactams polymerized at 180 DEG C.