Title:  Propylene glycol alginate gels

United States Patent:  6,509,311

Issued:  January 21, 2003

Inventors:  Colegrove; George Thomas (San Diego, CA)

Assignee:  ISP Investments Inc. (Wilmington, DE)

Appl. No.:  941275

Filed:  August 28, 2001

A gel system comprising propylene glycol alginate and basic aluminum acetate salt. Also, disclosed is a personal care formulation comprising a room deodorant gel employing said gel system.

DETAILED DESCRIPTION OF THE INVENTION

In this invention, the combination of propylene glycol alginate and an aluminum salt, preferably a sparingly soluble aluminum salt, such as basic aluminum acetate, Al(OH)(C₂ H₃ O₂)₂, provides a useful range of gels, whose characteristics will depend upon the degree of esterification of the alginate and the amount of aluminum salt used. Gel textures ranging from soft and elastic to firm and rigid can be made herein as the components are varied. For example, propylene glycol alginates with a high degree of esterification generally will produce soft, elastic gels while a lower degree of esterification will provide firm, brittle gels.

Advantageously, in this invention, gelation does not occur immediately so that a sequestrant is not needed to slow down the rate of reaction, as in previous alginate gel systems. Actually, the aluminum salt may be added to the alginate in an aqueous medium and the resulting solution filled into a container before gelation occurs. Reaction of the propylene glycol alginate with the sparingly soluble aluminum salt is slowed down herein by the presence of the ester group in the alginate so that some period of time is required to build-up the gel structure. In this manner, a very desirable uniform gel is obtained.

In the preferred forms of the invention, the propylene glycol alginate is esterified to about 40-90%; its concentration in the aqueous gel system is about 0.5-5.0 wt. %, most preferably 1-2.5 wt. %; and the aluminum salt concentration will provide 20-100% of complete reaction with the carboxyl groups of the alginate, most preferably 35-75%.

Claim 1 of 10 Claims

What is claimed is:

1. A gel system comprising propylene glycol alginate having a degree of esterification in the range of 40-90% and a sparingly soluble aluminum salt; and

optionally a nonionic polymeric viscosifier; and

wherein said aluminum salt is basic aluminum acetate in the range of 20-100% of complete reaction with the carboxyl groups of the alginate and said gel is made in the absence of a sequestrant.
 

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