| 摘要 |
In the production of rubber threads, tubes, rods, and the like by the extrusion of sensitized latex through heated nozzles, the rate of extrusion is increased by bringing the dispersion into the coagulating zone at a temperature approaching that of coagulation. This increases the rate of coagulation and liberates serum which acts as a lubricant between the coagulum and the walls of the nozzle. Lubricants such as glycerine, alkaline soaps, saponin, glucose may also be added for the same purpose. The dispersion may be heated to 40-60 DEG C. and cooled prior to the addition of sensitizing agents, or it may be heated after such addition until a slight thickening occurs. According to an example, 167 gm. of 60 per cent latex are added vulcanizing and antiageing agents suspended in 10 c.c. of water and 12 c.c. of glycerine; 0,5 gm. of ammonium sulphate in 2 c.c. of water and 1,7 gm. of zinc sulphate in 18 c.c. of ammonia solution are added and the dispersion is heated to 50 DEG C. for an hour to thicken it. Extrusion takes place at a pressure of 0,25 atm. through a nozzle of 2,5 mm. diameter, the first 20 cm. of which is heated to 83-85 DEG C., and the 10 cm. near the outlet, to 91-93 DEG C., the coagulating temperature being 87-80 DEG C. Specifications 284,608, 292,964, 330,520, 335,621, [all in Class 70], and 351,012 are referred to.
|
