Process for preparing silicone elastomer compositions

• US 5,854,336 A
• Filed: 03/20/1997
• Issued: 12/29/1998
• Est. Priority Date: 03/20/1997
• Status: Expired due to Term

• Current Assignee: Chesebrough-Pond'S Usa Co., Division Of Conopco, Inc.
• Original Assignee: Chesebrough-Pond'S Usa Co., Division Of Conopco, Inc.
• Inventors: Divone, Peter Anthony Sr., Dobkowski, Brian John, Biercevicz, Walter Anthony, Cheney, Michael Charles, Pliego, Salvador, Manzari, Kenneth Paul
• Primary Examiner(s): NILAND, PATRICK DENNIS
• Application Number:
  US08/822,406
• Time in Patent Office: 649 Days
• Field of Search: 528/502 C, 528/502 F, 528/15, 524/267, 524/588, 523/223, 523/318
• US Class Current: 524/588
• CPC Class Codes: A61K 2800/412 Microsized, i.e. having sizes between 0.1 and 100 microns
• CPC Class Codes: A61K 8/068 Microemulsions
• CPC Class Codes: A61K 8/891 saturated, e.g. dimethicone, phenyl trimethicone, C24-C28 methicone or stearyl dimethicone
• CPC Class Codes: A61K 8/895 containing silicon bound to unsaturated aliphatic groups, e.g. vinyl dimethicone
• CPC Class Codes: A61K 9/0004 Osmotic delivery systems; Sustained release driven by osmosis, thermal energy or gas
• CPC Class Codes: A61K 9/209 containing drug in at least two layers or in the core and in at least one outer layer
• CPC Class Codes: A61Q 15/00 Anti-perspirants or body deodorants deodorisation of air A61L9/00
• CPC Class Codes: A61Q 19/00 Preparations for care of the skin
• CPC Class Codes: B01J 2/18 using a vibrating apparatus
• CPC Class Codes: B01J 2/20 by expressing the material, e.g. through sieves and fragmenting the extruded length
• CPC Class Codes: B29B 9/00 Making granules in general B01J; chemical aspects C08J3/12
• CPC Class Codes: C08J 3/09 in organic liquids

Abstract

A process is provided for preparing a silicone elastomer composition for cosmetic products which includes the steps of feeding the silicone elastomer composition comprising a silicone rubber in a carrier fluid into a reactor, mixing the composition in the reactor, delivering the composition from the reactor into a high pressure pump, pumping the fluid into a device for reducing particles of rubber into smaller sizes and recirculating the resultant size reduced particles back to the reactor. The device for reducing particle size is preferably a high pressure fed homogenizer, most advantageously a sonolator.

Claims

1. A process for preparing silicone elastomer compositions for use in cosmetic products which compositions comprise a silicone elastomer within a carrier fluid, the process comprising the steps of:

(i) feeding the silicone elastomer composition into a reactor;

(ii) mixing the silicone elastomer composition through agitation in the reactor;

(iii) transferring the agitated silicone elastomer composition from the reactor into a high pressure pump;

(iv) pumping the mixed silicone elastomer composition at a pressure ranging from 500 to 40,000 psi from the high pressure pump into a means for reducing the silicone elastomer within the composition into a smaller particle size;

(v) optionally, recirculating the resultant smaller sized silicone elastomer particles into the reactor; and

(vi) recovering a silicone elastomer composition wherein the silicone elastomer average particle size ranges from 0.05 to 30 micron.

2. The process according to claim 1 wherein pumping is performed at a pressure from 1,800 to 10,000 psi.

3. The process according to claim 1 wherein temperature ranges from 20°

to 100°

C.

4. The process according to claim 1 wherein recirculating between step (ii) and (v) ranges from 1 to 200 passes.

5. The process according to claim 1 wherein the means is a homogenizer.

6. The process according to claim 5 wherein the homogenizer is a device capable of converting kinetic energy of a high velocity stream of liquid into a high intensity mixing action, conversion being accomplished by pumping the liquid through an orifice against a bladelike obstacle immediately in the stream of the liquid.

7. The process according to claim 1 wherein the silicone elastomer is dispersed within a silicone carrier.

8. The process according to claim 1 wherein the average particle size ranges from 0.5 to 5 micron.

9. The process according to claim 1 wherein the silicone elastomer is a crosslinked non-emulsifying polysiloxane prepared from the reaction of a vinyl monomer and a Si--H siloxane.

10. The process according to claim 1 wherein the carrier fluid is cyclomethicone.

11. The process according to claim 1 further comprising applying high-shear force onto the mixed silicone elastomer composition subsequent to step (ii) but prior to step (iv).

12. The process according to claim 1 wherein the transferring step (iii) is with a positive displacement pump.