Organopolysiloxane Emulsions and Their Production

• US 20120020909A1
• Filed: 03/30/2010
• Published: 01/26/2012
• Est. Priority Date: 03/31/2009
• Status: Active Grant

• Current Assignee: Dow, Inc.
• Original Assignee: Dow, Inc.
• Inventors: Courel, Benedicte, Davio, Delphine, Stammer, Andreas, Stassen, Sophie
• Granted Patent: US 8,597,624 B2
• Time in Patent Office: Days
• US Class Current: 424/70.12
• CPC Class Codes: A61K 8/06 Emulsions
• CPC Class Codes: A61K 8/062 Oil-in-water emulsions
• CPC Class Codes: A61K 8/892 modified by a hydroxy group, e.g. dimethiconol
• CPC Class Codes: A61K 8/922 of vegetable origin
• CPC Class Codes: A61Q 19/00 Preparations for care of the skin
• CPC Class Codes: C08G 77/06 Preparatory processes C08G77/045 takes precedence
• CPC Class Codes: C08J 2383/04 Polysiloxanes
• CPC Class Codes: C08J 2391/06 Waxes
• CPC Class Codes: C08J 3/05 from solid polymers
• CPC Class Codes: C08L 2201/52 Aqueous emulsion or latex, e.g. containing polymers of a glass transition temperature (Tg) below 20°C
• CPC Class Codes: C08L 83/04 Polysiloxanes

Abstract

This invention relates to aqueous emulsions comprising a polyorganosiloxane and a wax, and to methods of production of such emulsions. The emulsions are of the type oil-in-water. An organopolysiloxane is polymerized in admixture with a molten wax, thereby forming a blend of the wax with an organopolysiloxane of increased molecular weight, and the said blend of polymer and molten wax is emulsified in water in the presence of a surfactant. The emulsions are useful in personal care applications such as on hair, skin, mucous membrane or teeth. The emulsions are also useful in applications such as paints, water based coatings, textile fibre treatment, leather lubrication, fabric softening, fabric care in laundry applications, homecare, release agents and oil drag reduction.

Claims

1. A method of producing an aqueous emulsion of a polyorganosiloxane and a wax, wherein an organopolysiloxane is polymerized in an admixture with a molten wax, thereby forming a blend of the wax with an organopolysiloxane of increased molecular weight, and the blend of polymer and molten wax is emulsified in water in the presence of a surfactant.

2. The method according to claim 1, wherein the organopolysiloxane is a substantially linear organopolysiloxane containing at least one hydroxyl or hydrolysable group bonded to silicon and is polymerized by catalysed condensation of the hydroxyl or hydrolysable group to form siloxane bonds.

3. The method according to claim 1, wherein the organopolysiloxane comprises a cyclic organopolysiloxane and is polymerized by a catalysed process of ring opening of the cyclic organopolysiloxane to form siloxane bonds.

4. The method according to claim 1, wherein the organopolysiloxane is a mixture of a substantially linear organopolysiloxane containing at least one hydroxyl or hydrolysable group bonded to silicon and an alkoxysilane having an average of more than two alkoxy groups per molecule, and is polymerized by catalysed siloxane condensation of the substantially linear organopolysiloxane with the alkoxysilane to form a branched organopolysiloxane structure.

5. The method according to claim 2, wherein the substantially linear organopolysiloxane is a polydimethylsiloxane having terminal hydroxyl groups bonded to silicon and having a viscosity between 10 mPa·

s and 500 mPa·

s.

6. The method according to claim 2, wherein the polymerization is catalysed by a phosphazene catalyst, a Lewis acid or base.

7. The method according to claim 1, wherein the wax has a melting point in the range 30 to 80°

C.

8. The method according to claim 1, wherein the wax is a hydrocarbon wax, an ester wax or a silicone wax.

9. The method according to claim 1, wherein the weight ratio of organopolysiloxane to wax present during the polymerization is from 95:

5 to 40;

60.

10. The method according to claim 1, wherein the surfactant is a nonionic surfactant.

11. The method according to claim 1, wherein the blend of the wax with an organopolysiloxane of increased molecular weight produced in the polymerization reaction is emulsified before the reaction product has cooled to a paste or solid.

12. The method according to claim 1, wherein the blend of the wax with an organopolysiloxane of increased molecular weight produced in the polymerization reaction is cooled to a paste or solid and is subsequently heated to melt the wax and emulsified at a temperature above the melting point of the wax.

13. The method according to claim 1, wherein the emulsification is carried out by mixing the blend of polymer and wax with 1 to 20% by weight of water in the presence of 1 to 30% by weight surfactant, followed by at least one step of mixing the resulting emulsion with water until the desired concentration of emulsified wax organopolysiloxane blend in water is reached.

14. A silicone oil-in-water emulsion, wherein the disperse phase is a blend of a wax with an organopolysiloxane which has been formed by polymerization in the presence of the wax.

15. The silicone oil-in-water emulsion according to claim 14, wherein the organopolysiloxane has a weight average molecular weight of at least 100,000.