Granted Patent B2

US 6,984,705 · App. 10/233,950 · Granted Jan 10, 2006

Abstract

Claims (19)

1. A method of preparing highly cross linked expandable polymeric microparticles having an unexpanded volume average particle size diameter of from about 0.05 to about 10 microns comprising polymerizing one or more allylic, vinylic or acrylic monomers under free-radical forming conditions in the presence of about 9,000 to about 200,000 ppm of labile cross linkers and 0 to about 300 ppm of non-labile cross linkers.

2. The method of claim 1 wherein the polymeric microparticle has an unexpanded volume average particle size diameter of from about 0.1 to about 3 microns.

3. The method of claim 1 wherein the polymeric microparticle has an unexpanded volume average particle size diameter of from about 0.1 to about 1 microns.

4. The method of claim 1 wherein the monomers are acrylic monomers.

5. The method of claim 4 wherein the acrylic monomers are selected from the group consisting of nonionic, cationic, anionic, betaine and ampholytic ion pairs.

6. The method of claim 5 wherein the nonionic monomers are selected from acryloyl morpholine acrylamide, N-methylacrylamide, N,N-dimethylacrylamide and methacrylamide.

7. The method of claim 5 wherein the cationic monomers are selected from methacrylamidopropyl trimethyl ammonium chloride, acrylamidopropyl trimethyl ammonium chloride dimethylaminoethylacrylate methyl chloride quaternary salt, dimethylaminoethylmethacrylate methyl chloride quaternary salt and diallyldimethyl ammonium chloride.

8. The method of claim 5 wherein the anionic monomers are selected from 2-acrylamido-2-methyl propanesulfonic acid sodium salt, vinyl sulfonic acid sodium salt and styrene sulfonic acid sodium salt.

9. The method of claim 5 wherein the ampholytic ion pair monomers are selected from acid-base salts of a basic, nitrogen-containing monomer selected from dimethylaminoethylacrylate (DMAEA), dimethylaminoethyl methacrylate (DMAEM) and 2-methacryloyloxyethyldiethylamine and an acidic monomer selected from acrylic acid, 2-acrylamido-2-methylpropane sulfonic acid, 2-methacryloyloxyethane sulfonic acid, vinyl sulfonic acid and styrene sulfonic acid.

10. The method of claim 5 wherein the betaine monomer is N,N-dimethyl-N-methacryloyloxyethyl-N-(3-sulfopropyl)-ammonium betaine.

11. The method of claim 1 wherein the labile cross linker is selected from diacrylates and polyfunctional vinyl derivatives of a polyalcohol.

12. The method of claim 11 wherein the labile cross linker is polyethyleneglycol diacrylate.

13. The method of claim 1 wherein the non-labile cross linker is selected from methylene bisacrylamide, diallylamine, triallylamine, divinyl sulfone, diethyleneglycol diallyl ether.

14. The method of claim 13 wherein the non-labile cross linker is methylene bisacrylamide.

15. The method of claim 1 wherein the cross linked expandable polymeric microparticle is an amphoteric microparticle comprising one or more anionic monomers and one or more cationic monomers.

16. The method of claim 15 wherein the amphoteric polymeric microparticle has a higher than 1:1 anionic monomer/cationic monomer mole ratio.

17. The method of claim 16 wherein the amphoteric polymeric microparticle comprises one or more nonionic monomers, one or more anionic monomers and one or more cationic monomers.

18. The method of claim 1 wherein the cross linked expandable polymeric microparticle is a betaine-containing polymeric microparticle.

19. The method of claim 1 wherein the cross linked expandable polymeric microparticle is an ion pair-containing polymeric microparticle.

Assignments (15)