Patent ID: 8349953
Filing Date: 2013-01-08
Classification: B29B,B29C,C08L

Abstract:
1. A method for melting and shearing polymers in a cylinder into which an inner feedback screw is inserted, the inner feedback screw having a screw structure at a surface of the inner feedback screw and an inner hole extending from a front end side to a rear end side of the inner feedback screw, a sealing surface being provided at a front end side of the cylinder and facing the front end side of the inner feedback screw so as to form a gap between the sealing surface and the front end side, the method comprising: (a) supplying polymers into the cylinder from the rear end side of the inner feedback screw; (b) generating a flow of the supplied polymers on the screw structure of the inner feedback screw in the cylinder by rotating the inner feedback screw; (c) melting and shearing the polymers by rotating the inner feedback screw, while forwarding the polymers to the front end side of the inner feedback screw; (d) further rotating the inner feedback screw, thereby filling the polymers into the gap formed between the front end side of the inner feedback screw and the sealing surface provided at the front end side of the cylinder; (e) further rotating the inner feedback screw, thereby returning the polymers toward the rear end side of the inner feedback screw through the inner hole of the inner feedback screw; (f) repeating said steps (c) to (e) to circulate the polymers in the cylinder; and (g) ejecting from the cylinder the polymers which have been melted and sheared, wherein the method further comprises determining a size of the gap and a size of an inner diameter of the inner hole of the inner feedback screw depending on a viscosity of the polymers.