Drug – bio-affecting and body treating compositions – Live hair or scalp treating compositions – Two or more designated surfactant containing
Reexamination Certificate
1999-09-15
2001-02-20
Naff, David M. (Department: 1651)
Drug, bio-affecting and body treating compositions
Live hair or scalp treating compositions
Two or more designated surfactant containing
C424S070210, C424S070220, C424S070270, C424S070310
Reexamination Certificate
active
06190646
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a biodegradation accelerator of hydrophobic pollutants such as hydrocarbons, of oil/water microemulsions, also called nutrient microemulsions, which are consumable by microorganisms.
2. Description of the Related Art
The formulation of the nutrient microemulsions in the past has represented a significant advance in the marketing of additives which are useful as biodegradation accelerators. For example, French Patent Nos. 2,490,672 and 2,512,057 describe such accelerators, which are formulated as an internal phase of an aqueous solution of nitrogenous and phosphorus compounds, preferably phosphorous surfactants, this phase being dispersed in an external hydrophobic phase formed of an easily assimilated carbon source. In these emulsions, the nitrogenous compounds employed are, for example, amino acids, proteins, or urea, and phosphorous compounds of surfactants of the alkyl or alkenyl phosphoric ester type. The hydrophobic external phase is formed of a carbon source easily assimilated by microorganisms, such as vegetable oils or, animal oils and fatty acids, which are selected in order to be compatible with the products to be degraded.
The effectiveness of these known emulsions as biodegradation accelerators has been clearly demonstrated in numerous industrial applications, especially in the treatment of effects of marine pollution resulting from accidental spills of hydrocarbons and in the treatment procedures which are directed to the rehabilitation of soil contaminated with hydrophobic pollutants such as described in patent WO 95/06715.
Despite the qualities of nutrient microemulsions, their use remains limited on account of difficulty in use, in particular at temperatures below 10° C.
The microemulsions described in the state of the art are generally applied in spray form to the contaminated zones or mixed with polluted soil. They must therefore exhibit certain fluidity and a certain stability favoring such applications. Yet, these microemulsions have the disadvantage of separating into two immiscible phases near 0° C. In addition, whenever an ambient temperature lower than 20° C. is reached, these microemulsions become very viscous (more than 1,000 mPa·sec), which makes their use on the soil very tricky or even impossible in certain forms of application such as by a spray.
Of course, attempts have been made to remedy this major drawback by the addition of organic compounds, such as alcohols and glycol ethers, to decrease the viscosity of these microemulsions at these temperatures, as is mentioned in application WO 9/07508. Thus, by adding from 10 to 15% ethylene glycol butyl ether, a decrease in the viscosity to approximately 200 mPa·sec at 20° C. has been observed, allowing spraying of the product with conventional equipment at this temperature, or an easier spreading. However, to apply these microemulsions at a lower temperature, in particular below 10° C., it is currently advisable either to store the microemulsions at 20° C. in order to spray the microemulsions at this temperature, or to reheat the microemulsions on site while the microemulsions are reformed and/or become fluid again. It is a major drawback for the user who, as the product is transformed, is no longer certain of the quality of his product. Therefore, it is understood why the use of this biodegradation accelerator, otherwise remarkable in its effectiveness, has not been widely extended to all applications for marine or terrestrial biodegradation, in particular, in cold countries.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide a microemulsion which is useful as a biodegradation accelerator which is nontoxic, which is stable at temperatures from −10° C. to +50° C., and which has a fluidity at +5° C. which is sufficient for use in the applications desired.
Briefly, this object and other object of the present invention as hereinafter will become more readily apparent can be attained by a microemulsion which is useful as a biodegradation accelerator, the microemulsion containing (1) at least one nitrogenous compound such as amino acids, proteins, urea and its derivatives, (2) from 10 to 35% by weight of a phosphorus surfactant compound of the alkyl or alkenyl phosphoric ester type, the ester being a mono- and/or dialkyl- or mono- and/or dialkenylphosphoric ester wherein the alkyl and alkenyl groups contain less than 12 carbon atoms per alkyl or alkenyl chain, preferably from 3 to 10 carbon atoms and containing from 1 to 10 alkoxylated radicals, preferably ethoxy and/or propoxy groups, (3) from 3 to 20% by weight of at least one cosurfactant, (4) a compound selected from the group consisting of vegetable oils, animal oils and fatty acids, and (5) a plasticizer, said emulsion having a viscosity at 5° C. less than or equal to 200 mPa·sec and stable at a temperature of −10° to +50° C.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the present invention, it is the combined effect of the surfactants derived from the above specific phosphoric esters, with a cosurfactant or a mixture of cosurfactants, which assures the stability of the microemulsion down to a very low temperature, at least −10° C., and allows the product to be used without difficulty in any cold environment.
The cosurfactants according to the invention are selected from compounds with an oral toxicity in rats, such that the lethal dose for 50% of the microorganisms is higher than 2 g/kg.
The cosurfactants are preferably selected as presenting a melting point lower than 0° C., and preferably lower than −20° C., and/or a solubility in water greater than 2 g for 100 g of water, and preferably greater than 10 g for 100 g of water, these two parameters are capable of study independently or simultaneously, according to the conditions of use of the microemulsions. It is easily understood that an expert in the field can be led to adjust the composition of the microemulsion according to whether it is a question of spraying on a polluted zone at sea or of treating soil to be rehabilitated, and according to temperature of use of these procedures.
The cosurfactants with the required characteristics for inclusion in the microemulsion according to the invention, alone or in a mixture, are selected from mono- and polyhydroxylated alcohols containing less than 10 carbon atoms, and their ether derivatives; mono- and polycarboxylic, acids or esters, possibly mono or polyhydroxylated and including C
1
to C
7
carbon length chains; straight-chain ketones including at least 5 carbon atoms, and lactones.
Suitable monoalcohols useful as cosurfactants of the invention include C
2
to C
8
alkanols, with C
2
to C
4
preferred.
Preferred polyalcohols are diols, especially substituted ethylene glycols or their oligomers, and their ether derivatives with 4 to 10 carbon atoms. In particular, the preferred ether derivatives include diethylene glycol butyl ether, ethylene glycol monoethyl ether, and ethylene glycol monomethyl ether.
Preferred monocarboxylic compounds, optionally hydroxylated, are carboxylic acids having 1 to 4 carbon atoms and their esters derived from C
1
to C
5
monoalcohols. Especially preferred monocarboxylic compounds are formic, acetic, butyric, and lactic acids, and their alkyl esters containing up to 6 carbon atoms the alkyl group, with n-butyl formate and ethyl lactate being preferred.
Preferred dicarboxylic compounds, optionally hydroxylated, are dicarboxylated acids containing from 3 to 6 carbon atoms and their esters from C
1
to C
5
monoalcohols. Especially preferred dicarboxylic compound are malonic and succinic acids and their esters, preferably dialkyl malonates, including diethyl malonate, and the dialkyl succinates, including dimethyl succinate.
Suitable preferred ketones of the invention include dialkyl detones containing, at most, 6 carbon atoms, especially methyl ethyl ketone.
The preferred lactone is &ggr;-butyrolactone.
According to the present invention the preferre
Basseres Anne
Brochette Pascal
Espert Alexandre
Tellier Jacques
Elf Aquitaine
Naff David M.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ware Deborah K.
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