| 摘要 |
Aromatic polyisocyanates containing sulphonic acid or sulphonate groups which are substantially free from crystalline product and a method for making them are provided wherein a mixture of aromatic polyisocyanates having an isocyanato content of from about 10% to about 42% by weight is sulphonated, the improvement which comprises mixing and reacting liquid aromatic polyisocyanates having a viscosity of from about 8 cP to about 49 cP at 25 DEG C. and containing at least 40% by weight of phosgenation products of an aniline-phosgenation condensate and at least about 20% by weight of 2,6-tolylene diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate or a mixture thereof, based on the weight of said liquid aromatic polyisocyanates with a sulphonating agent in an amount equivalent to from about 0.1% to about 40% by weight sulphur trioxide, based on the weight of said liquid aromatic polyisocyanates.
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