Patent ID: 6274637
Filing Date: 2001-08-14
Classification: B29B,Y02W

Abstract:
Process for recycling waste plastic comprising at least two different plastic materials, the method comprising:(a) combining a carrier material A comprising a plastic material and up to 10% by volume of contaminants and a second material X in a ratio A:X of from 1:50 to 50:1, a plastics content of the mixture of A and X being at least 50% by volume, wherein said material X is selected from the group consisting of plastics-containing waste material which is different from the plastics-containing carrier material A, household refuse, bulky refuse, paper, cardboard, plastics-coated cardboard, plastics-coated waste paper, landfill refuse, metal, wood, wood residues, sawdust, rubber, and glass fibers;(b) combining the mixture of A and X with an additional component Z which is selected from the group consisting of fatty acids, mixtures containing fatty acid of natural or synthetic origin, fatty acid derivatives which release fatty acid under process conditions in step (d) and fatty alcohols, to form a mixture of plastics, wherein the additional component Z is added, relative to the volume of the mixture of A and X, in a quantity of 0.01 to 10%;(c) forming the mixture of plastics into granular beads of 1 to 5 mm in diameter(d) conveying the granular beads through a conveying device with mechanical mixing, kneading or compression, subjecting along a transport path to a sectional multistage thermal treatment, the multistage thermal treatment comprising three stages, the temperature being ini) a first stage 60 to 130.degree. C.,ii) a second stage, 130 to 180.degree. C., andiii) a third stage, 160 to 380.degree. C., to form a thermally treated mixture; and(e) discharging the thermally treated mixture via a nozzle for further treatment or for shaping.