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AssigneeHoechst Aktiengesellschaft
InventorsRudolf Heinrich, Heinz Frensch, Konrad Albrecht
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Pressure-resistant polyurethane-polyurea particles with textured internal mass prepared from a liquid phase immiscible with water and containing organic solvents, isocyanate prepolymers and optionally active substances or mixtures of active substances, the liquid phase being dispersed in an aqueous phase at temperatures of from 0.degree. C. to 95.degree. C., wherein the liquid organic phase contains as isocyanate prepolymer a reaction product of a stoichiometric excess of an aliphatic, aromatic, cycloaliphatic, or araliphatic di- or polyisocyanate with a di- or polyol, the reaction product having a mean molecular weight in the range of from about 300 to 10,000, and an alkyl and/or alkoxyalkyl acetate of the formula ##STR1## in which m is zero, 1 or 2, n is 1 to 4, and R is (C.sub.1 -C.sub.5)alkyl, and the aqueous phase contains a protective colloid and optionally a surface-active agent.
A process for the manufacture of pressure-resistance internally textured polyurethane-polyurea particles which comprises forming an organic solvent solution of isocyanate prepolymer which is a reaction product of a stoichiometric excess of an aliphatic, aromatic, cycloaliphatic or araliphatic di- or polyisocyanate with a diol or polyol, said reaction product having a mean molecular weight of from about 300 to 10,000, said organic solvent solution also containing from 2 to 85% by weight an alkyl and/or alkoxyalkyl acetate of the formula ##STR3## in which m is 0 to 2
Dependencies are inferred from the claim text.