反应详情

87 grams (0.5 mol) of toluene diisocyanate and 0.027 g of phenothiazine are placed in a 500 cm3 reactor under a nitrogen atmosphere. The temperature is kept at between 48° and 50° C. and 58 g, that is to say 0.5 mol, of freshly distilled hydroxyethyl acrylate are added in the course of two hours. When the introduction is complete, the mixture is stirred for a further 3 hours at the same temperature and 223 g, that is to say 0.25 mol, of an aliphatic polycarbonate-diol are then added, the latter having a molecular weight of 890 and being obtained by the phosgenation of a mixture of butane-1,4-diol and hexane-1,6-diol in proportions which are such that the resulting polycarbonate is equivalent to a mixture of 50% by weight of a polycarbonate obtained from hexane-1,6-diol by itself and 50% by weight of a polycarbonate obtained from butane-1,4-diol by itself. The reaction is allowed to proceed for 3 hours at 50° C. A few drops of methanol are added in order to neutralise any free isocyanate groups which could have remained.

1. customis kept at between 48° and 50° C.