| 主权项 |
1. A process for producing emulsion polymer particles, comprising polymerizing in a sequential polymerization
i) a seed, and ii) then reacting with a swell-seed comprising 55 to 99.9 wt % of one or more nonionic ethylenically unsaturated monomer and 0.1 to 45 wt % of one or more ethylenically unsaturated hydrophilic monomer, all based on an overall weight of a core stage polymer comprising both seed and swell-seed, iii) then polymerizing a first shell comprising 85 to 99.9 wt % of one or more than nonionic ethylenically unsaturated monomer and 0.1 to 15 wt % of one or more hydrophilic ethylenically unsaturated monomer, iv) then polymerizing a second shell comprising 85 to 99.9 wt % of one or more nonionic ethylenically unsaturated monomer and 0.1 to 15 wt % of one or more hydrophilic ethylenically unsaturated monomer, v) then adding at least one plasticizer monomer having a ceiling temperature below 181° C., vi) neutralizing, to a pH of not less than 7.5 or greater, the resultant particles with one or more bases, vii) then polymerizing a third shell comprising 90 to 99.9 wt % of one or more nonionic ethylenically unsaturated monomer and 0.1 to 10 wt % of one or more hydrophilic ethylenically unsaturated monomer, viii) and also optionally polymerizing one or more further shells comprising one or more nonionic ethylenically unsaturated monomer and one or more hydrophilic ethylenically unsaturated monomer, wherein
a weight ratio of the swell-seed (ii) to the seed polymer (i) is in a range from 10:1 to 150:1,a weight ratio of the core stage polymer to the first shell (iii) is in a range from 2:1 to 1:5, anda weight ratio of the third shell (vii) to the second shell (iv) is in a range from 1:2 to 1:10. |
