| 摘要 |
A colouring composition containing an acrylic microgel resin which is prepared from an aqueous microgel emulsion obtained by the emulsion polymerization of a mixture of ethylenically unsaturated monomers in water. At least one of these monomers is an acrylic acid or a methacrylic acid, or else an OH-substituted alkyl ester thereof containing a COOH or OH group. At least one of the other said monomers is an alkyl ester of an acrylic acid or methacrylic acid, styrene or alpha-methylstyrene and is free of COOH and OH groups. The preparation also involves a multifunctional crosslinking agent used in an amount of 5-70 wt-% calculated on the total weight of the said ethylenically unsaturated monomers and the crosslinking agent. The water is then removed from the emulsion by coagulation and/or azeotropic distillation with an organic solvent in which the microgel is insoluble, and which forms an azeotropic mixture with water. The microgel is then incorporated in an acrylic resin prepared by polymerizing two or more ethylenically unsaturated monomers in an organic solvent. At least one of these monomers is an OH-substituted alkyl ester of an acrylic acid or methacrylic acid and possibly a monomer that contains a COOH group and is an acrylic acid or a methacrylic acid. Another of the said monomers is an alkyl ester of an acrylic acid or methacrylic acid, styrene or alpha-methylstyrene and is free of COOH and OH groups. The aim of this procedure is to obtain the said acrylic microgel resin, in which the amount of solids in the microgel is 5-15 wt-%, calculated on the total amount of solids in the resin. |
