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US 6,444,749 B1Granted
Aqueous dispersions of particles of polymers with a glass transition temperature gradient
AssigneeAkzo Nobel N.V.
InventorDirk Emiel Paula Mestach
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AssigneeAkzo Nobel N.V.
InventorDirk Emiel Paula Mestach
Estimating the term…
The invention pertains to an aqueous dispersion of particles of a polymer having a functional group for cross-linking, which is obtainable by a free radical emulsion polymerization of at least two different ethylenically unsaturated monomers, a surfactant of the formula M+.−OOC—CH═CHCOOR, wherein R is C(6-22) alkyl and M+ is Na+, K+, Li+, NH4+, or a protonated or quaternary amine, and a co-reactive compound having at least two groups capable of reacting with the functional group for cross-linking, characterized in that the glass-transition temperature (Tg) of the polymer at the center of the particle is different from the Tg of the polymer at the surface of the particle, the difference being at least 55° C., and the Tg of the polymer having the highest Tg is at least 40° C.
An aqueous dispersion of polymer particles having a functional group for cross-linking, is obtained by a free radical emulsion polymerization of at least two different ethylenically unsaturated monomers, a surfactant of the formula M+.−OOC—CH═CHCOOR, wherein R is C(6-22) alkyl and M+ is Na+, K+, Li+, NH4+, or a protonated or quaternary amine, and a co-reactive compound having at least two groups capable of reacting with the functional group for cross-linking, wherein the glass transition temperature (Tg) of the polymer at the center of the particle is different from the Tg of the polymer at the surface of the particle, the difference being at least 55° C., and the Tg of the polymer having the highest Tg is at least 40° C.
Dependencies are inferred from the claim text.