Multistage polymers and compositions thereof

A multilayer particle comprising

• (i) a first layer comprising a first copolymer having a first theoretical glass transition temperature (Tg), the first copolymer being derived from a soft ethylenically-unsaturated monomer, a phosphorus-containing monomer, and an acetoacetoxy monomer;
• and
• (ii) a second layer surrounding at least a portion of the first layer comprising a second polymer having a second theoretical Tg, the second polymer being derived from at least 50% by weight of one or more hard ethylenically-unsaturated monomers, based on the total weight of monomers used to form the second polymer;
• wherein the second theoretical Tg is at least 40° C. greater than the first theoretical Tg.

A multilayer particle comprising

• (i) a first layer comprising a first copolymer derived from a soft ethylenically-unsaturated monomer, a phosphorus-containing monomer, and an acetoacetoxy monomer;
• and
• (ii) a second layer surrounding at least a portion of the first layer comprising a second polymer derived from at least 90% by weight of one or more hard ethylenically-unsaturated monomers selected from the group consisting of methyl methacrylate, styrene, and combinations thereof, based on the total weight of monomers used to form the second polymer;
• wherein the particle exhibits a single Tg, measured using DSC, ranging from −10° C. to 25° C.