Patent GB-833756-A (GB)
Title: Process and apparatus for the production of oriented artificial filaments
IPC: D02J1/22
Filed: 1956-09-12
Abstract: Oriented artificial filaments are made by melt-spinning a thermoplastic high polymer to form monofilaments, causing or allowing the filaments to solidify, contacting the travelling solidified filaments with a heated surface, or with a series of such surfaces, all moving in the direction of the path of travel of the filaments while in contact with the filaments by means of which surface or surfaces the temperature of the filaments is adjusted to the orientation temperature, and stretching the filaments while they are maintained at this temperature after they have left the heated moving surface or surfaces.  Preferably the filaments after orientation are cooled while under tension.  The monofilaments may be of polystyrene, the temperature of which is preferably adjusted for orientation to a value between 210 DEG  and 300 DEG  F.  As shown in Fig. 1, monofilaments extruded from the melt-spinning head 2 are brought down to the required orientation temperature as they are conveyed by heated motor-driven rollers 3-11 to point A, between which and the cooling bath 13 they are oriented or stretched by their passage over the rollers 14, 15 which are driven at a peripheral speed greater than that of the rollers 3-11.  As shown in Fig. 2, heated rollers 3-11 and rollers 14, 15 are driven by a motor 20 in combination with a conventional variable-speed pulley arrangement and multiple chain and sprocket drive.  The heated rollers 5-11 and the portion of the filament path in which the filaments are stretched are enclosed in a thermally-insulated housing member having the top and walls substantially air-tight.  As shown in Figs. 1-4, the housing member comprises integrally connected front 52 and sides 53, 54, and separate back 55.  Front 52 and sides 53, 54 are vertically adjustable by means of a counterweight 56 enclosed in casing 57 and connected by means of a rope 58 to sides 53, 54 at brackets 64, 65. The vertical movement of the assembly 52-54 is guided by the fixed rods 66, 67 provided with guide rollers 76, 77.  The separate back 55 and vertical strips 82-85 are bolted to a frame member 86, and the inwardly-turned lips 80, 81 of sides 53, 54 are adapted to slide in the vertical slots provided by the strips 82-85 so that the assembly 52-54 of the housing can be vertically adjusted while maintaining substantially airtight contact with the separate back 55.  Also connected to frame member 86 is a vertical plate 91 which has vertical spaced openings in alignment with spaced openings in back 55 through which pass the shafts 38a and 40a-45a of heated rollers 5 to 11.  Each of the shafts, as illustrated by shaft 42a shown in Fig. 4, has mounted thereon a floating brass bush 92 which fits snugly between back 55 and plate 91 to accommodate vertical movement of the shaft without causing an air leak between the shaft and the fixed back of the housing.  Each of the shafts is rotatably supported in a <PICT:0833756/IV (a)/1> <PICT:0833756/IV (a)/2> <PICT:0833756/IV (a)/3> <PICT:0833756/IV (a)/4> ball-bearing 93 mounted on a frame member 95.  Steam is passed into the interior of each of the hollow rollers 3-11 through fixed pipes, as illustrated by fixed pipe 108 (Fig. 4), which is located within the hollow shaft 42a, there being sufficient clearance between pipe 108 and shaft 42a to allow the steam to escape from the interior of the roller and pass to a steam trap. The filaments leaving the interior of the housing enclosing the heated rollers 5-11 are cooled while still under tension by passage through bath 13 under roller 12 and, after passing round rollers 14, 15, pass to filament guides 16, 17.