Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2000-04-10
2001-05-15
Ogden, Necholus (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S424000, C510S426000, C510S428000, C560S076000, C568S458000, C568S882000
Reexamination Certificate
active
06232282
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to a detergent composition containing a mid-chain branched surfactant and an electrolyte. More particularly, the detergent composition includes a mixture of linear alkybenzene sulfonate (“LAS”) surfactant and mid-chain branched primary alkyl sulfate surfactant and an electrolyte capable of increasing the ionic strength of the compositions resulting in improved performance, especially under low water temperature wash conditions.
1. Background of the Invention
Conventional detersive surfactants comprise molecules having a water-solubilizing substituent (hydrophilic group) and an oleophilic substituent (hydrophobic group). Such surfactants typically comprise hydrophilic groups such as carboxylate, sulfate, sulfonate, amine oxide, polyoxyethylene, and the like, attached to an alkyl, alkenyl or alkaryl hydrophobe usually containing from about 10 to about 20 carbon atoms. Accordingly, the manufacturer of such surfactants must have access to a source of hydrophobe groups to which the desired hydrophile can be attached by chemical means. The earliest source of hydrophobe groups comprised the natural fats and oils, which were converted into soaps (i.e., carboxylate hydrophile) by saponification with base. Coconut oil and palm oil are still used to manufacture soap, as well as to manufacture the alkyl sulfate (“AS”) class of surfactants. Other hydrophobes are available from petrochemicals, including alkylated benzene which is used to manufacture alkyl benzene sulfonate surfactants (“LAS”).
Generally, alkyl sulfates are well known to those skilled in the art of detersive surfactants. Alkyl sulfates were developed as a functional improvement over traditional soap surfactants and have been found to possess improved solubility and surfactant characteristics. Linear alkyl sulfates are the most commonly used of the alkyl sulfate surfactants and are the easiest to obtain. For example, long-chain linear alkyl sulfates, such as tallow alkyl sulfite, have been used in laundry detergents. However, these have significant cleaning performance limitations, especially with the trend to lower wash temperatures. Accordingly, there is a need for a detergent composition which includes a surfactant capable of delivering improved cleaning at low wash water temperatures (e.g., 20° C.-5° C.). Moreover, even detergent compositions containing surfactants having the desired performance have room for improved performance. In particular, certain detergent compositions containing selected surfactants such as mid-chain branched surfactants typically include other ingredients such as adjunct surfactants (e.g., LAS) builders, enzymes and the like which can have deleterious effects on the overall cost of the composition. To that end, a need continues to exist for a detergent composition having a mid-chain surfactant, which is less expensive and yet, exhibits improved performance.
2. Background Art
U.S. Pat. No. 3,480,556 to deWitt, et al., Nov. 25, 1969, EP 439,316, published by Lever Jul. 31, 1991, and EP 684,300, published by Lever Nov. 29, 1995, describe beta-branched alkyl sulfates. EP 439,316 describes certain laundry detergents containing a specific commercial C14/C15 branched primary alkyl sulfate, namely LIAL 145 sulfate. This is believed to have 61% branching in the 2-position; 30% of this involves branching with a hydrocarbon chain having four or more carbon atoms. U.S. Pat. No. 3,480,556 describes mixtures of from 10 to 90 parts of a straight chain primary alkyl sulfate and from 90 to 10 parts of a beta branched (2-position branched) primary alcohol sulfate of formula:
wherein the total number of carbon atoms ranges from 12 to 20 and R1 is a straight chain alkyl radical containing 9 to 17 carbon atoms and R2 is a straight chain alkyl radical containing 1 to 9 carbon atoms (67% 2-methyl and 33% 2-ethyl branching is exemplified).
As noted hereinbefore, R. G. Laughlin in “The Aqueous Phase Behavior of Surfactants”, Academic Press, N.Y. (1994) p. 347 describes the observation that as branching moves away from the 2-alkyl position towards the center of the alkyl hydrophobe there is a lowering of Krafft temperatures. See also Finger et al., “Detergent alcohols—the effect of alcohol structure and molecular weight on surfactant properties”, J. Amer. Oil Chemists' Society, Vol. 44, p. 525 (1967) and Technical Bulletin, Shell Chemical Co., SC: 364-80.
EP 342,917 A, Unilever, published Nov. 23, 1989 describes laundry detergents containing a surfactant system in which the major anionic surfactant is an alkyl sulfate having an assertedly “wide range” of alkyl chain lengths (the experimental appears to involve mixing coconut and tallow chain length surfactants).
U.S. Pat. No. 4,102,823 and GB 1,399,966 describe other laundry compositions containing conventional alkyl sulfates.
G.B. Patent 1,299,966, Matheson et al., published Jul. 2, 1975, discloses a detergent composition in which the surfactant system is comprised of a mixture of sodium tallow alkyl sulfate and nonionic surfactants.
Methyl—substituted sulfates include the known “isostearyl” sulfates; these are typically mixtures of isomeric sulfates having a total of 18 carbon atoms. For example, EP 401,462 A, assigned to Henkel, published Dec. 12, 1990, describes certain isostearyl alcohols and ethoxylated isostearyl alcohols and their sulfation to produce the corresponding alkyl sulfates such as sodium isostearyl sulfate. See also K.R. Wormuth and S. Zushma, Langmuir, Vol. 7, (1991), pp 2048-2053 (technical studies on a number of branched alkyl sulfates, especially the “branched Guerbet” type); R. Varadaraj et al., J. Phys. Chem., Vol. 95, (1991), pp 1671-1676 (which describes the surface tensions of a variety of “linear Guerbet” and “branched Guerbet”—class suffactants including alkyl sulfates); Varadaraj et al., J. Colloid and Interface Sci., Vol. 140, (1990), pp 31-34 (relating to foaming data for surfactants which include C12 and C13 alkyl sulfates containing 3 and 4 methyl branches, respectively); and Varadaraj et al., Langmuir, Vol. 6 (1990), pp 1376-1378 (which describes the micropolarity of aqueous micellar solutions of surfactants including branched alkyl sulfates).
“Linear Guerbet” alcohols are available from Henkel, e.g., EUTANOL G-16.
Primary akyl sulfates derived from alcohols made by Oxo reaction on propylene or n-butylene oligomers are described in U.S. Pat. No. 5,245,072 assigned to Mobil Corp. See also: U.S. Pat. No. 5,284,989, assigned to Mobil Oil Corp. (a method for producing substantially linear hydrocarbons by oligomerizing a lower olefin at elevated temperatures with constrained intermediate pore siliceous acidic zeolite), and U.S. Pat. Nos. 5,026,933 and 4,870,038, both to Mobil Oil Corp. (a process for producing substantially linear hydrocarbons by oligomerizing a lower olefin at elevated temperatures with siliceous acidic ZSM-23 zeolite).
See also: Surfactant Science Series, Marcel Dekker, N.Y. (various volumes include those entitled “Anionic Surfactants” and “Surfactant Biodegradation”, the latter by R. D. Swisher, Second Edition, publ. 1987 as Vol. 18; see especially p.20-24 “Hydrophobic groups and their sources”; pp 28-29 “Alcohols”, pp 34-35 “Primary Alkyl Sulfates” and pp 35-36 “Secondary Alkyl Sulfates”); and literature on “higher” or “detergent” alcohols from which alkyl sulfates are typically made, including: CEH Marketing Research Report “Detergent Alcohols” by R. F. Modler et al., Chemical Economics Handbook, 1993, 609.5000-609.5002; Kirk Othmer's Encyclopedia of Chemical Technology, 4
th
Edition, Wiley, N.Y., 1991, “Alcohols, Higher Aliphatic” in Vol. 1, pp 865-913 and references therein.
SUMMARY OF THE INVENTION
The invention meets the needs in the art by providing a detergent composition, granular or liquid, which contains a mixture of LAS surfactant and a mid-chain branched alkyl sulfate surfactant and an optimally selected level of an electrolyte such as sodium chloride. By including the electrolyte in the detergent composition, the ionic strength of th
Godfroid Robert Allen
Heltovics Gabor
Katsuda Rinko
Kvietok Frank Andrej
Vinson Phillip Kyle
Dressman Marianne
Miller Steven W.
Ogden Necholus
The Procter & Gamble & Company
William Zerby Kim
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