METHOD FOR OBTAINING POLYOLS AND POLYOL THUS OBTAINED.

摘要

The invention relates to the field of polymer chemistry. It features a method for obtaining polyols consisting in a first step in reacting glycols, i.e. plurialcohols with a functionality at least equal to two (MEG, DEG, DPG,...) on polyethyleneterephthalate (PET) in the presence of a transesterefication catalyst (CAT) (MEG, DEG, DPG;...), on polyethyleneterephthalate (PET) in the presence of a glycolysis catalyst (CAT), then in a last step, in distilling the free glycols. The method is characterised in that a step subsequent to the first and prior to, or simultaneous with, the last step, comprises the glycolysis catalyst deactivation by a deactivating agent (DES). As an example, the glycolysis reaction catalyst (CAT) is one of the agents of the group comprising zinc acetate and manganese acetate, amines such as triethylamine and tributylamine, and the selected deactivating agent is phosphoric acid at 85 %. The method comprises various embodiments, one of which comprises glycerol as one of the plurialcohols. The invention is useful for recycling polyethyleneterephthalates used as packaging material.