Method of forming particles from an oil-in-water emulsion

1. A method of forming particles having an average diameter of at least 30 nanometers, said method comprising the steps of:

A. reacting a silanol and a cyclic silazane to form an amino-functional polysiloxane;

B. forming an oil-in-water emulsion comprising the amino-functional polysiloxane and less than 0.1 weight percent of a hydrophobic costabilizer;

C. combining the amino-functional polysiloxane and an isocyanate in the oil-in-water emulsion to react and form the particles having the average diameter of at least 30 nanometers.

2. The method of claim 1 wherein the step of forming the oil-in-water emulsion is further defined as forming a water-in-oil emulsion comprising the amino-functional polysiloxane and less than 0.1 weight percent of a hydrophobic costabilizer and phase inverting the water-in-oil emulsion to form the oil-in-water emulsion.

3. The method of claim 1 wherein the step of forming the oil-in-water emulsion is further defined as forming a water-in-oil emulsion comprising the amino-functional polysiloxane and less than 0.1 weight percent of a hydrophobic costabilizer and applying shear to the water-in-oil emulsion to form the oil-in-water emulsion.

4. The method of claim 1 wherein the silanol has the chemical formula H(OSiR 1 R 2 ) n OH wherein each of R 1 and R 2 is independently selected from the group of alkyl groups, cyclic alkyl groups, aromatic groups, and combinations thereof and n is a number of from 1 to 2,000.

5. The method of claim 4 wherein n is a number of from 200 to 900.

6. The method of claim 4 wherein R 1 and R 2 are both methyl groups.

7. The method of claim 1 wherein the cyclic silazane is further defined as 1,1,2,4-tetramethyl-1-sila-2-azacyclopentane.

8. The method of claim 1 wherein the amino-functional polysiloxane is further defined as an amino-functional polydimethylsiloxane.

9. The method of claim 1 wherein the particles have an average diameter of from greater than 500 nanometers up to 1,000 nanometers.

10. The method of claim 1 wherein the particles have a dynamic viscosity of at least 100 million centipoise measured at a temperature of 25° C. and at 10 −1 Hertz.

11. The method of claim 1 wherein the oil-in-water emulsion is free of the hydrophobic costabilizer, the silanol has the chemical formula H(OSiR 1 R 2 ) n OH wherein each of R 1 and R 2 are methyl groups, and n is a number from 700 to 900, the cyclic silazane is further defined as 1,1,2,4-tetramethyl-1-sila-2-azacyclopentane, the amino-functional polysiloxane is further defined as an amino-functional polydimethylsiloxane, the isocyanate is further defined as hexamethylene diisocyanate, and the particles have an average diameter of greater than 500 nanometers and up to 1,000 nanometers.

12. A personal care composition comprising particles formed from the method of claim 1 , wherein the particles have a dynamic viscosity of at least 100 million centipoise measured at a temperature of 25° C. and at 10 −1 Hertz.

13. A film comprising the particles formed from the method of claim 1 , wherein the particles have a dynamic viscosity of at least 100 million centipoise measured at a temperature of 25° C. and at 10 −1 Hertz.

14. A method of forming particles having an average diameter of at least 30 nanometers, said method comprising the step of forming an oil-in-water emulsion comprising a silanol, a cyclic silazane, an isocyanate and less than 0.1 weight percent of a hydrophobic costabilizer such that the silanol, the cyclic silazane, and the isocyanate react to form the particles having the average diameter of at least 30 nanometers.

15. The method of claim 14 wherein the step of forming the oil-in-water emulsion is further defined as forming a water-in-oil emulsion comprising the silanol, the cyclic silazane, the isocyanate, and less than 0.1 weight percent of a hydrophobic costabilizer and phase inverting the water-in-oil emulsion to form the oil-in-water emulsion; or applying shear to the water-in-oil emulsion to form the oil-in-water emulsion.

16. The method of claim 15 wherein the oil-in-water emulsion is free of the hydrophobic costabilizer, the silanol has the chemical formula H(OSiR 1 R 2 ) n OH wherein each of R 1 and R 2 is independently selected from the group of alkyl groups, cyclic alkyl groups, and combinations thereof, and n is a number from 700 to 900, the cyclic silazane is further defined as 1,1,2,4-tetramethyl-1-sila-2-azacyclopentane, the isocyanate is further defined as hexamethylene diisocyanate, and the particles have an average diameter of greater than 500 nanometers and up to 1,000 nanometers.

17. An oil-in-water emulsion comprising:

A. particles having an average diameter of at least 30 nanometers and comprising a polymerization product of a silanol, a cyclic silazane, and an isocyanate polymerized in the oil-in-water emulsion; and

B. less than 0.1 weight percent of a hydrophobic costabilizer, wherein said particles have a dynamic viscosity of at least 100 million centipoise measured at a temperature of 25° C. and at 10 −1 Hertz.

18. The oil-in-water emulsion of claim 17 wherein said silanol has the chemical formula H(OSiR 1 R 2 ) n OH wherein each of R 1 and R 2 is independently selected from the group of alkyl groups, cyclic alkyl groups, and combinations thereof and n is a number of from 1 to 2,000.

19. The oil-in-water emulsion of claim 18 wherein said cyclic silazane is further defined as 1,1,2,4-tetramethyl-1-sila-2-azacyclopentane, n is a number of from 700 to 900, the isocyanate is further defined as hexamethylene diisocyanate, and the particles have a diameter of greater than 500 nanometers and up to 1,000 nanometers.