Patent ID: 11970599
Assignee: TRINSEO EUROPE GMBH
Field: Macromolecular chemistry, polymers (Chemistry)
Classification: CPC C | IPC C

Claim 18:
19. A composition comprising a structure having a shell which surrounds air and a dried polymeric acid core of one or more polymers of one or more hydrophilic ethylenically unsaturated monomers containing acid functionality, one or more nonionic hydrophilic ethylenically unsaturated monomers and, optionally one or more hydrophobic ethylenically unsaturated monomers having up to about 50 percent by weight of the one or more hydrophilic ethylenically unsaturated monomers containing acid functionality, the shell having one or more layers, wherein the layers comprise polymers of one or more of one or more hydrophilic ethylenically unsaturated monomers containing acid functionality, one or more hydrophobic ethylenically unsaturated monomers and one or more nonionic hydrophilic ethylenically unsaturated monomers, wherein the shell layers have up to about 40 percent by weight of the one or more hydrophilic ethylenically unsaturated monomers containing acid functionality; wherein the concentration of the one or more hydrophilic ethylenically unsaturated monomers containing acid functionality decreases from the inside to the outside of the shell, a portion of the dried polymeric acid core is in contact with the inside of the shell and the structure has a mean volume particle size of about 750 nm to 2000 nm and the volume of the air inside the shell is 40 percent or greater based on the volume of the hollow polymeric spheres, the particle size distribution is such that 90 percent of the particles lie within 10 percent of the volume average particle size and the residual monomer level in the particles is 200 ppm based on weight or less, wherein the particle size is determined from magnified scanning electron microscope pictures wherein the non-collapsed particles are measured and the particle size distribution is calculated from the measured particle sizes.