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Abstract

This invention relates to a process for the preparation of aqueous emulsions of blocked (poly)isocyanates, this process comprising the steps consisting successively in: a) placing an isocyanate composition containing free isocyanate functions in contact with at least one blocking agent A in the presence of a surfactant B and an aqueous phase, the said isocyanate composition being added gradually to a stock containing at least some of the aqueous phase and at least some of the blocking agent; and optionally, b) subjecting the mixture obtained to a shear (speed gradient) of greater than 1000 s.sup.-1, preferably greater than 20,000 s.sup.-1 and less than 1,000,000 s.sup.-1, preferably less than 200,000 s.sup.-1, and c) repeating step b), optionally after step a) has been repeated, until a stable emulsion is obtained whose particles have a Sauter diameter of greater than 0.1 .mu.m, preferably 0.2 .mu.m, and less than 5 .mu.m, preferably less than 2 .mu.m, and a dispersion width of less than 5 .mu.m.

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First Claim