Clear silicone microemulsions

• US 6,616,934 B1
• Filed: 05/22/2000
• Issued: 09/09/2003
• Est. Priority Date: 05/22/2000
• Status: Expired due to Term

• Current Assignee: Dow, Inc.
• Original Assignee: Dow, Inc.
• Inventors: Hill, Randal Myron, Lin, Zuchen
• Primary Examiner(s): Padmanabhan, Sreeni
• Assistant Examiner(s): Wells, Lauren Q.
• Application Number:
  US09/575,258
• Time in Patent Office: 1,205 Days
• Field of Search: 424/78.03, 424/401, 524/837, 514/937
• US Class Current: 424/401
• CPC Class Codes: A61K 8/064 Water-in-oil emulsions, e.g. Water-in-silicone emulsions
• CPC Class Codes: A61K 8/068 Microemulsions
• CPC Class Codes: A61K 8/585 Organosilicon compounds
• CPC Class Codes: A61K 8/894 modified by a polyoxyalkylene group, e.g. cetyl dimethicone copolyol
• CPC Class Codes: A61Q 19/00 Preparations for care of the skin
• CPC Class Codes: A61Q 5/00 Preparations for care of the hair

Abstract

Spontaneously formed highly stable clear water-in-oil microemulsions containing only small amounts of water can be prepared by combining and simply hand shaking (i) 0.1 to 9 percent by weight of water; (ii) greater than 80 percent by weight of a volatile cyclic alkyl siloxane or volatile linear alkyl siloxane; and (iii) 3 to 10 percent by weight of certain silicone polyether surfactants. The microemulsions are useful in personal care applications.

Claims

1. A water-in-oil microemulsion comprising (i) 0.1 to 9 percent by weight of water;

(ii) greater than 80 percent by weight of a cyclic alkyl siloxane oil having the formula (R₂SiO)_p or a linear alkyl siloxane oil having the formula R₃SiO(R₂SiO)_qSiR₃ in which R is an alkyl group containing 1-6 carbon atoms, p is 3-6, and q is 0-5; and

(iii) 3 to 10 percent by weight of a silicone polyether having a formula selected from the group consisting of

where R1 represents an alkyl group containing 1-6 carbon atoms;

R2 represents the radical —

(CH₂(_aO(C₂H₄O)_b(C₃H₆O)_cR₃;

x has a value of 0-3;

y has a value of 1-3;

z has a value of 0-2;

m has a value of 3-5;

n is one;

a has a value of 0-6;

b has a value of 2-6;

c has a value of 0-3; and

R3 is hydrogen, a methyl radical, or an acyl radical;

the water-in-oil microemulsion containing domains of oil or water having an average diameter of less than 100 nanometer (0.1 micron/1,000 angstrom Å

).

2. A microemulsion according to claim 1 in which the alkyl siloxane is present in the amount of 81 to 96.9 percent by weight.

3. A microemulsion according to claim 1 in which the alkyl siloxane is present in an amount greater than 85 percent by weight.

4. A microemulsion according to claim 1 in which the alkyl siloxane is octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, or a mixture of octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane.

5. A personal care product containing the microemulsion of claim 1.

6. A method of treating hair or skin comprising applying to the hair or skin the microemulsion or a composition containing the microemulsion of claim 1.