Claims
- 1. A method of preparing a monodisperse latex having an average particle size of at least 2-30 microns, which comprises polmerizing a mixture of:
- (A) about 2-30 parts by weight of a monodisperse seed latex polymer of particle size on the order of 2 microns or less, said seed latex polymer containing a non-polymeric anionic emulsifier;
- (B) about 10-50 parts by weight of a polymerizable, non-crosslinking monomer component selected from vinyl aromatic monomers and mixtures of vinyl aromatic monomers and different ethylenically unsaturated monomers;
- (C) 0 to about 0.1 parts by weight of a polyethylenically unsaturated crosslinking monomer;
- (D) about 0.01-0.2 parts by weight of an oil-soluble, sparingly water-soluble free radical initiator;
- (E) about 0.001 to 0.1 parts by weight of at least one water-soluble of partially water-soluble and oil-soluble free radical inhibitor;
- (F) an emulsifier component comprising:
- (i) about 0.05-2.0 parts by weight of a first water-soluble polymeric emulsifier of molecular weight of about 10.sup.4 -10.sup.7 selected from at least one of:
- a polyvinyl pyrrolidone in the presence of a water-soluble carboxylic oligomer emulsifier of molecular weight of about 0.3.times.10.sup.3 -5.times.10.sup.3,
- a 95.0-99.8% nonionic hydrophilic backbone monomer/0-2.0% hydrophobic monomer/0.2-3.0% ionic monomer copolymer,
- a polyacrylamide, and
- a hydroxyethyl cellulose;
- (ii) 0 to about 0.05 parts by weight of a second water-soluble comonomeric or polymeric emulsifier of molecular weight of about 0.3.times.10.sup.3 -5.times.10.sup.3 ;
- (iii) 0 to about 0.01 parts by weight of a non-polymeric anionic emulsifier; and
- (G) the balance being water, to make 100 parts by weight of total mixture.
- 2. The method of claim 1 wherein, in the nonionic hydrophilic backbone monomer/hydrophobic monomer/ionic monomer copolymer of the first water-soluble polymeric emulsifier (i) of emulsifier component (F) for polymerizing monomer component (B) in the presence of seed latex polymer (A), the backbone monomer is vinyl pyrrolidone, the hydrophobic monomer is selected from isodecylmethacrylate, acrylates or methacrylates of C.sub.6 -C.sub.20 monohydroxy alcohols, and vinyl aromatic monomers, and the ionic monomer is sodium vinylsulfonate;
- wherein the second comonomeric or polymeric emulsifier (ii) of emulsifier component (F) is at least one of a carboxylic oligomer, a sodium short-chain vinylsulfonate, a sodium styrene sulfonate and a sodium vinyltoluene sulfonate;
- and wherein the non-polymeric anionic emulsifier (iii) of emulsifier component (F) is at least one of sodium dodecyl sulfate, dihexyl ester of sulfosuccinic acid sodium salt and di-2-ethylhexyl ester of sulfosuccinic acid sodium salt.
- 3. The method of claim 1 wherein the initiator (D) is at least one of
- 2,2'-azobis-(2-methylbutyronitrile) and
- 2,2'-azobis-(isobutyronitrile).
- 4. The method of claim 1 wherein the inhibitor (E) is at least one of hydroquinone, benzoquinone, catechol, pyrrogallol, thiourea and dimethyldithiocarbamate.
- 5. The method of claim 1 wherein the polymer (A) is polystyrene and the non-crosslinking monomer (B) is styrene.
- 6. The method of claim 1 wherein the crosslinking monomer (C) is divinylbenzene.
- 7. The method of claim 1 wherein the emulsifier component (F) includes said second polymeric emulsifier (ii).
- 8. The method of claim 1 wherein the emulsifier component (F) includes said anionic emulsifier (iii).
- 9. The method of claim 1 wherein the emulsifier component (F) includes both of said second polymeric emulsifier (ii) and said anionic emulsifier (iii).
- 10. A method as in claim 1 wherein the polymerization is conducted in a microgravity environment.
- 11. A method as in claim 2 wherein the polymerization is conducted in a microgravity environment.
- 12. The monodisperse latex produced by the method of claim 1.
- 13. The monodisperse latex produced by the method of claim 2.
- 14. monodisperse latex produced by the method of claim 5.
- 15. The monodisperse latex produced by the method of claim 10.
- 16. The monodisperse latex produced by the method of claim 11.
- 17. The method of claim 1 wherein the hydrophilic backbone monomer/hydrophobic monomer/ionic monomer copolymer of emulsifier component (F) (i) is selected from a vinylpyrrolidone/sodium vinylsulfonate copolymer and a vinylpyrrolidone/isodecyl methacrylate/sodium vinylsulfonate terpolymer.
- 18. The method of claim 2 wherein the seed latex polmer (A) is polystyrene and the non-crosslinking monomer component (B) is styrene.
ORIGIN OF THE INVENTION
The invention described herein was made in the performance of work under a contract with the National Aeronautics and Space Administration.
US Referenced Citations (5)
Foreign Referenced Citations (2)
Number |
Date |
Country |
0920867 |
Mar 1963 |
GBX |
1339182 |
Nov 1973 |
GBX |