The Center for Disease Control recommends “[k]eeping hands clean is one of the most important steps we can take to avoid getting sick and spreading germs to others. It is best to wash your hands with soap and clean running water for 20 seconds. However, if soap and clean water are not available, use an alcohol-based product to clean your hands. Alcohol-based hand rubs significantly reduce the number of germs on skin and are fast acting”. (“Clean Hands Save Lives”; Source: Coordinating Center for Infectious Diseases”; [online], Dated: May 11, 2006, [retrieved on Aug. 22, 2006]. Retrieved from the internet: <URL: http://www.cdc.gov/cleanhands/>.)
Washing with soap and water is not always available or convenient. Adults often don't have time to wash thoroughly and children often don't do a complete job due to inexperience or distraction. Thus, many people use hand sanitizers in the absence of soap and water.
For alcohol based hand sanitizers, the Food and Drug Administration (FDA) recommends a concentration of 60% to 95% ethanol, the concentration range of greatest germicidal efficacy. (Food and Drug Administration. Topical antimicrobial products for over-the-counter use; tentative final monograph for healthcare antiseptic drug products. Federal Register. 1994; 59:31221-2.)
In the past, lower alcohols (C1-C4), such as ethanol, were considered to be de-foamers rather than foam promoting compounds. U.S. Pat. No. 3,131,153 to Klausner, herein incorporated by reference, describes that in foam producing compositions using propellants, decreasing amounts of alcohol in the formulation favors a more stable foam. If the amounts of alcohol are outside the indicated critical ranges of 26-64%, emulsification will result, rather than a homogeneous composition. U.S. Pat. No. 3,962,150A to Viola, herein incorporated by reference, describes foam-producing skin cleansing compositions suitable for use in a non-pressurized system, including a total surfactant composition of from 1 to 15% and from 1.0 to 15.0% of an alcoholic solvent having from 2 to 3 carbon atoms and from 70 to 98% by weight of water. U.S. Pat. No. 6,518,229B2 to Tashjian et al, herein incorporated by reference, describes a non-alcohol foaming antibacterial soap composition which includes an anionic surfactant, an amphoteric surfactant, a cationic conditioning agent, an antibacterial agent, such as Triclosan®, and water. To obtain a high level of foam, an amphoteric surfactant is used to function as a foam booster.
Various examples of foaming lower alcohol (C1-C4) compositions comprised of a high content of alcohol have been described. U.S. Pat. No. 5,167,950 to Lins, herein incorporated by reference, describes an antimicrobial aerosol mousse having a high alcohol content of at least 52%.
US20050129626 to Koivisto et al and US20060104919 to Novak, both of which are herein incorporated by reference, describe foaming a high alcohol content composition including a lower alcohol and perfluorinated surfactants. Perfluorinated surfactants are synthetic chemicals that do not occur naturally in the environment. Perfluorinated surfactants are sometimes referred to as “C8”, because a typical structure has a linear chain of eight fluorinated carbon atoms. Perfluorinated surfactants are sometimes employed in the production of fluoropolymers, substances with special properties that have thousands of important manufacturing and industrial applications.
Commonly used perfluorinated surfactants and their derivates include perfluoroalkyl phosphate salt, perfluoroalkyl phosphate compounds, fluoroaliphatic phosphate esters, fluoroaliphatic amine oxides, polytetrafluoroethylene acetoxypropyl betaine, anionic phosphate fluorosurfactant and mixtures thereof Perfluorinated surfactants can also include ethoxylates, glycerol esters, amine oxides, acetylenic alcohol derivatives, carboxylates, phosphates, carbohydrate derivatives, sulfonates, betaines, esters, polyamides, silicones, and hydrocarbon surfactants that have been fluorinated. Accordingly, the use of these surfactants are described in US 20060104919A1 to Novak and US 20050129626 to Koivisto et al.
In 1999, the EPA became interested in perfluorinated compounds after receiving data on perfluorooctyl sulfonate (PFOS). Data showed that PFOS was persistent, unexpectedly toxic, bioaccumulative, and found in very low concentrations in the blood of the general population and in wildlife around the world. In general, the durability of perfluorinated compounds prevent them from breaking down once in the environment and this results in the buildup and bioaccumulation in the environment. (“Perfluorooctanoic acid (PFOA)”; Source: Environmental Protection Agency (EPA).) [online], dated: unknown, [retrieved on Aug. 22, 2006]. Retrieved from the internet: <URL:http://www.epa.gov/oppt/pfoa/>.)
On Feb. 15, 2006, the EPA's Science Advisory Board voted to approve a recommendation that certain perfluorinated surfactants should be considered as likely carcinogenic.
The fluorosurfactants used in the present invention are polymeric fluorosurfactants with pendant perfluoroalkyl side chains of a fully fluorinated chain length of C1-C7 and are not known to bioaccumulate. Furthermore, the polymeric fluorosurfactants of the present invention are surprisingly and unexpectedly useful to foam formulations containing a lower alcohol and water. Accordingly, it has been known in the art that such polymeric fluorosurfactants exhibit very low foaming characteristics. (Omnova Solutions Inc., “Fluorosurfactants for Improved Flow, Leveling and Surface Appearance in Aqueous Coatings”, Mar. 7, 2006.)
The invention overcomes the shortcomings of past compositions by providing a foaming composition, which includes a lower alcohol but does not use a fluorosurfactant known to bioaccumulate in the environment.
USPTO Backgrounds
USPTO Backgrounds