Verfahren zum Herstellen von Strangpressprofilen

摘要

1,125,403. Extruding polyamide sections. BADISCHE ANILIN- & SODA-FABRIK A.G. 7 Jan., 1966 [9 Jan., 1965], No. 776/66. Heading B5A. Polyamide rods 8 of various cross-sections are formed by ram extrusion of a supercooled melt of the resin through a cooled die 7. The term " supercooled melt " is defined as the state of the melt when at a temperature of 5-10‹ C. below its melting-point after polymerization, but before crystallization sets in. The extrusion process comprises two stages; in the first a mixture 2 of a lactam, catalyst and activator is homogenized by means of a plate 1 within a mixing vessel heated to the polymerization temperature, and in the second the mixing vessel is placed within barrel 6 of the extruder where anionic polymerization takes place and the bottom 3, Fig. 1, or 10, Fig. 2, of the vessel, which is movable, is acted upon by a ram 11. The preferred range of polymerization temperatures is 100-140‹ C. and that for extrusion is 180-210‹ C. According to the invention the rods have a monomer content of less than 1À2% by weight and a water absorption of less than 50% by weight and the rods may be stretched by rollers or a sizing die to increase their strength. Gearwheels may be made from the rods. Numerous lactams, activators and catalysts are listed as well as conventional additives. An example is given.