Method for Preparing Polymer Particles
AssigneeValspar Sourcing, Inc.
InventorsMartin Peter Josep Heuts, Archie W. Garner
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Abstract
A polymer particle (10) useful for opacifying includes a polymer core (12) and a polymer sheath (16) surrounding the polymer core (12). The polymer core (12) is produced by polymerizing the polymer sheath (16) around the polymer core (12) in an emulsion. After at least a portion of the polymer core (12) is formed, a non-homopolymerizing monomer is added to the emulsion.
Claims21
A method for preparing emulsion polymer particles useful for opacifying, the method comprising:
- polymerizing a polymer sheath around a swellable polymer core in an emulsion;
- treating the polymer core with a swelling agent to swell the polymer core;
- adding a non-homopolymerizing monomer to increase a concentration of free monomer in the emulsion;
- and then
- decreasing the concentration of free monomer in the emulsion.
A method for preparing emulsion opacifying polymer particles, the method comprising:
- emulsion polymerizing a polymer core;
- exposing the polymer core to a supply of free monomer to form a polymer sheath around the polymer core;
- after forming at least a portion of the polymer sheath, exposing the polymer core to an amount of a swelling agent sufficient to swell the polymer core;
- changing the composition of the supply of free monomer to include an amount of non-homopolymerizing monomer;
- and then
- decreasing the amount of non-homopolymerizing monomer in the supply of free monomer.
A composition useful for opacifying, the composition comprising:
- a base-swellable polymer core;
- a polymer sheath around the polymer core, the polymer sheath comprising between about 1 and about 20 weight percent of non-homopolymerizing monomer;
- wherein the non-homopolymerizing monomer comprises a substance of the formula:
- and anhydrides thereof;
- wherein:
- X are moieties independently selected from hydrogen, a halogen, or an organic group;
- and
- at least two X moieties are selected independently from R1, COOR2, and Ar, wherein:
- R1 is an organic group;
- R2 is hydrogen, a halogen, or an organic group;
- and
- Ar is a phenyl group of the chemical formula C6(R3)5 and R3 are independently hydrogen, a halogen, or an organic group.
Dependencies are inferred from the claim text.