A method for the production of from the melt spinnable poly ethylene terephthalate

摘要

Spinnable polyethylene terephthalate is made from polyethylene terephthalate waste by (1) exposing the waste on the countercurrent principle to a stream of superheated steam, the inlet temperature of which is 280 DEG C. to 450 DEG C. and the outlet temperature of which is not below 200 DEG C., (2)adding an aromatic or hydroaromatic ketone or diketone (e.g. 4-methylcyclohexanone or benzil) to the melt thus formed and, (3) polycondensing the melt. Treatment with the steam is preferably effected in a vertical jacketted tube into which polyethylene terephthalate fibre waste is fed at the top, steam at 420 DEG C. is fed at the bottom and steam at 200 DEG to 220 DEG C. is fed at the mid-point. The steam removes textile auxiliaries from the waste and the ketones combine with metals in the melt to form colourless compounds. There may be added to the melt, prior to polycondensation, ethylene glycol, pigments, dyestuffs, stabilizers or optical brighteners.