| 摘要 |
1,116,415. Cast polymerization of polyamides. BADISCHE ANILIN- & SODA-FABRIK A.G. 12 Oct., 1965 [13 Oct., 1964], No. 43162/65. Heading B5A. Copolyamide mouldings are rotationally or centrifugally cast by polymerizing a molten mixture of at least two lactams having at least seven ring members, e.g. capryllactam and caprolactam, with alkaline catalysts and activators, whereby the relative proportions of lactams in the mixture is varied as the mixture, e.g. at 125‹ C., is being supplied to the mould, e.g. over a period of four minutes to a 500 mm. diameter cylinder heated to 150‹ C. and rotated at 600 r.p.m. Rollers may be produced, e.g. for calender rolls, which have a differing hardness from the surface to the interior thereof whereby internal stresses and cracking during machining are avoided. The lactam mixture may be introduced to the mould already mixed or via mixing nozzles whereby a mixture of one lactam with the catalyst and a mixture of the other lactam with the activator are supplied through two nozzles or mixtures of each lactam with the catalyst and of each with the activator are supplied through four nozzles. The mould is preferably heated to 80‹ to 200‹ C. prior to introducing the polymerization mixture and polymerization is effected with 0À01 to 5% by weight of catalyst and 0À05 to 10% of activator. Examples of lactam catalysts and activators are given, and the mouldings may also incorporate fillers, e.g. aluminium or copper, quartz powder, ground shale, sand, diatomaceous earth or polyamide and other plastics, reinforcements, e.g. glass staple, fleece or fabric, dulling agents, e.g. titanium dioxide or zinc oxide, and lubricants, e.g. graphite, lead powder or molybdenum disulphide. |
