| 摘要 |
The invention describes how a polymeric dispersion is obtained, having a minimum film formation temperature in range of 0 to 40 degree C, which is utilized in coating compositions for substrates, in varnishes or glossing paints form, by a step-wise emulsion polymerization, comprising polymerizing, in a first stage having monomeric composition I, comprising; from 50 to 68.5 percent by weight of smooth monomers A, the homopolymers of which have a glass transition temperature (Tg) lower than 0 degree C; from 30 to 50 percent by weight of hard monomers B, the homopolymers of which have a glass transition temperature (Tg) higher than 65 degree C; from 0.5 to 5 percent by weight of alpha,beta-unsaturated carboxylic acid and/or carboxy-amides C, which are copolymerizable with A and B; from 1 to 7.5 percent by weight of ethylenically unsaturated monomers D, containing keto groups; and from 0 to 10 percent by weight of other ethylenically unsaturated monomers E, containing a nitrogen atom; on each case based in first stage polymer total quantity; a second stage having monomeric composition II, comprising; from 5 to 45 percent by weight of smooth monomers A, the homopolymers of which have a glass transition temperature (Tg) lower than 0 degree C; from 65 to 95 percent by weight of hard monomers B, the homopolymers of which have a glass transition temperature (Tg) above 65 degree C; from 0 to 4 percent by weight of carboxylic acid carboxyamides C, which are copolymerizable with A and B; from 0 to 5 percent by weight of ethylenically unsaturated monomers D, containing keto groups; and from 0 to 10 percent by weight of other ethylenically unsaturated monomers E, containing a nitrogen atom; based, on each case, in second stage polymer total quantity, in a weight ratio of monomeric composition I to monomeric composition II of 50:50 to 75:25.
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