| 摘要 |
The invention comprises the reaction product of a liquid reaction mixture comprising a polyester prepared from at least one dicarboxylic acid and at least one glycol, the polyester having a molecular weight of from 1,500 to 2,500, a hydroxyl number of from 45 to 75 and an acid number not greater than 5, ortho dichlorobenzidine and 3, 31-dimethyl 4, 41-diphenylene diisocyanate, the diisocyanate being in a molar excess of at least 10% over the combined molecular amount of the dichlorobenzidine and the polyester. The polyester and diisocyanate may first be reacted at 100 DEG to 140 DEG C., the dichlorobenzene is then mixed in, and the mixture is poured into a mould where it cures, advantageously, although not necessarily, with heating. Succinic, glutaric, adipic, pimelic, suberic, azelaic and sebacic acids and ethylene, propylene, butylene, pentamethylene and hexamethylene glycols are specified for the preparation of the polyesters. Preferably 0,10 to 0,8 mols of odichlorobenzidine and 1,25 to 2 mols of the diisocyanate per mol of polyester are employed. Particularly preferred are the polyesters from adipic acid and a mixture of glycols containing approximately 80 mol per cent of ethylene glycol and 20 mol per cent of propylene glycol, in the molecular weight range of about 2,000 and having an acid number not greater than 2. Comparison results (smear point) of a product in accordance with the invention and products variously from 4, 41-diphenylene methane diisocyanate, m-phenylene diisocyanate, 1, 5-naphthalene diisocyanate, and (as cross-linking agents) o-dichlorobenzidine, methylene bis-o-chloroaniline and 1,4-butanediol, are given. |
