POLYMERIC BEADS AND METHODS OF MAKING POLYMERIC BEADS

• US 20080300339A1
• Filed: 06/07/2007
• Published: 12/04/2008
• Est. Priority Date: 05/31/2007
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Scholz, Matthew T., Wolk, Diane R., Zhang, Yifan, Buchholz, Jessica M., Ali, Mahfuza B., Svarovsky, Michael J., Walter, Richard L., Haddad, Louis C., Stepanova, Narina Y., Wright, Robin E., Ylitalo, Caroline M., Olson, Linda K.M.
• Granted Patent: US 8,513,322 B2
• Time in Patent Office: Days
• US Class Current: 522/154
• CPC Class Codes: C08F 2/06 Organic solvent
• CPC Class Codes: C08F 2/34 Polymerisation in gaseous state

Abstract

Polymeric beads and methods of making the polymeric beads are described. The polymeric beads are crosslinked hydrogels or dried hydrogels. The polymeric beads are formed from droplets of a precursor composition that are exposed to radiation. The droplets are totally surrounded by a gas phase. The precursor composition contains a polar solvent and a polymerizable material miscible in the polar solvent. The polymerizable material has an average number of ethylenically unsaturated groups per monomer molecule equal to at least 1.2.

Claims

1. A method of making a polymeric bead, the method comprising:

providing a precursor composition comprising;

a) greater than 10 weight percent polar solvent based on a total weight of the precursor composition; and

b) polymerizable material capable of free-radical polymerization and having an average number of ethylenically unsaturated groups per monomer molecule equal to at least 1.2, wherein the polymerizable material is miscible with the polar solvent;

forming a droplet of the precursor composition, wherein the droplet is totally surrounded by a gas phase; and

exposing the droplet to radiation for a time sufficient to at least partially polymerize the polymerizable material and to form a first swollen polymeric bead.

2. The method of claim 1, wherein the polymerizable material comprises a poly(alkylene oxide) (meth)acrylate) having an average number of (meth)acryloyl groups per monomer molecule equal to at least 2.

3. The method of claim 2, wherein the poly(alkylene oxide (meth)acrylate) has a weight average molecular weight no greater than 2000 g/mole.

4. The method of claim 1, wherein the method further comprises

removing at least a portion of the polar solvent from the first swollen bead to form a dried bead.

5. The method of claim 1, wherein the precursor composition further comprises an active agent.

6. The method of claim 5, wherein the active agent comprises a bioactive agent.

7. The method of claim 1, wherein the precursor composition further comprises a photoinitiator and the radiation comprises actinic radiation.

8. The method of claim 1, wherein the method further comprises

removing at least a portion of the polar solvent from the first swollen bead to form a dried bead;

and

contacting the dried bead with a sorbate for a time sufficient for the dried bead to sorb at least a portion of the sorbate to form a second swollen polymeric bead, wherein the sorbate comprises at least one active agent.

9. The method of claim 8, wherein the method further comprises drying the second swollen polymeric bead.

10. A method of preparing an article comprising a polymeric bead, the method comprising:

providing a precursor composition comprising

a) greater than 10 weight percent to 85 weight percent polar solvent based on a total weight of the precursor composition; and

b) 15 weight percent to less than 90 weight percent polymerizable material based on the total weight of the precursor composition, the polymerizable material being capable of free-radical polymerization and having an average number of ethylenically unsaturated groups per monomer molecule equal to at least 1.2, the polymerizable material being miscible in the polar solvent and comprising

i) a poly(alkylene oxide (meth)acrylate) having at least 2 (meth)acryloyl functionality groups and having at least 5 alkylene oxide units; and

ii) 0 to less than 20 weight percent anionic monomer based on a total weight of polymerizable material in the precursor composition, wherein the anionic monomer comprises an ethylenically unsaturated group in addition to an acidic group, a salt of the acidic group, or a mixture thereof,

forming a droplet of the precursor composition, wherein the droplet is totally surrounded by a gas phase; and

exposing the droplet to radiation for a time sufficient to at least partially polymerize the polymerizable material and to form a first swollen bead.

11. The method of claim 10, wherein the method further comprises

removing at least a portion of the polar solvent from the first swollen bead to form a dried bead.

12. The method of claim 10, wherein the precursor composition comprises less than 1 weight percent anionic monomer based on the weight of the polymerizable material.

13. The method of claim 10, wherein the poly(alkylene oxide (meth)acrylate) has a weight average molecular weight less than 2000 g/mole.

14. The method of claim 10, wherein the precursor composition further comprises an active agent.

15. The method of claim 14, wherein the active agent comprises a bioactive agent.

16. The method of claim 10, wherein the precursor composition further comprises a photoinitiator and the radiation comprises actinic radiation.

17. The method of claim 10, wherein the method further comprises

removing at least a portion of the polar solvent from the first swollen bead to form a dried bead;

and

contacting the dried bead with a sorbate for a time sufficient for the dried bead to sorb at least a portion of the sorbate to form a second swollen polymeric bead, wherein the sorbate comprises an active agent.

18. The method of claim 17, wherein the active agent comprises an ethylenically unsaturated group and a photoinitiator, the method further comprises exposing the second swollen polymeric bead to actinic radiation.

19. The method of claim 17, wherein the method further comprises drying the second swollen polymeric bead.

20. An article comprising a polymeric bead comprising a free-radical polymerization reaction product of a precursor composition comprising

a) greater than 10 weight percent to no greater than 85 weight percent polar solvent based on a total weight of the precursor composition;

and

b) 15 weight percent to less than 90 weight percent polymerizable material based on the total weight of the precursor composition, the polymerizable material being capable of free-radical polymerization and having an average number of ethylenically unsaturated groups per monomer molecule equal to at least 1.2, the polymerizable material being miscible in the polar solvent and comprising

i) a poly(alkylene oxide (meth)acrylate) having at least 2 (meth)acryloyl groups and having at least 5 alkylene oxide units; and

ii) 0 to less than 20 weight percent anionic monomer based on a total weight of polymerizable material in the precursor composition, wherein the anionic monomer comprises an ethylenically unsaturated group in addition to an acidic group, a salt of the acidic group, or a mixture thereof.

21. An article comprising a polymeric bead comprising:

a) a free-radical polymerization reaction product of a precursor composition comprising polymerizable material being capable of free-radical polymerization and having an average number of ethylenically unsaturated groups per monomer molecule equal to at least 1.2, the polymerizable material comprising

i) a poly(alkylene oxide (meth)acrylate) having at least 2 (meth)acryloyl groups and having at least 5 alkylene oxide units;

ii) 0 to less than 20 weight percent anionic monomer based on the total weight of polymerizable material in the precursor composition, wherein the anionic monomer comprises an ethylenically unsaturated group in addition to an acidic group, a salt of the acidic group, or a mixture thereof, and

b) an active agent.