The invention relates to light duty liquid detergent compositions, a method of making light duty liquid detergent composition, as well as methods for using such compositions.
Despite the popularity and convenience of automatic dishwashing machines, hand dishwashing remains a common activity among a large number of consumers. Light duty liquid detergents (also referred to as “LDLD” or “LDL”) are typically utilized for hand dish washing of kitchen utensils, plates, dishes, flatware, pots/pans, and other soiled food preparation items. Light duty liquid detergents are also commonly used to clean delicate textiles by hand as well as in the cleaning of automobile exteriors and many household hard surfaces, such as floors, painted woodwork, washable wallpaper and counter tops.
In general, it is desirable for LDL compositions to exhibit not only grease removal properties, but also high foaming characteristics, as consumers generally incorrectly associate the latter with the cleaning performance of the LDL. Also, as LDL compositions will usually come into contact not only with the surface to be cleaned, but also with the skin of the person who is cleaning, it is also desirable for the LDL to be mild and non-drying to human skin.
LDL compositions typically comprise a mixture of liquid surfactants. Many commercially available LDL compositions include one or more anionic surfactants that function as the primary cleaning component (or base surfactant formulation) within the LDL composition. In particular, alkylbenzene sulfonic acid is used extensively as it is an effective degreaser, has a good foam profile (except in hard water), is pH tolerant, and is low cost. Amines have been commonly used in LDL compositions as a source of alkalinity. Many LDL compositions further include divalent ions, such as Mg and Ca, to insure adequate cleaning of greasy soils in soft water. However, the use of such ions can have an undesirable effect on the stability of the LDL and may lead to the undesirable precipitation of such ions from the LDL.
U.S. Pat. No. 4,992,212 teaches the use of an organic base, a zinc salt and a complexing agent in a LDL composition to allow for the pretreatment of aluminum utensils with little or no associated staining of such utensils.
U.S. Pat. No. 5,981,466 describes a detergent composition, primarily for use in fabric laundering, which comprises alkyl alkoxylated sulfates and/or alkyl sulfates and specific primary and/or tertiary amines. However, there are limitations to the effectiveness of this formulation when as a LDL because of antagonist effects caused by the ether sulfates.
U.S. Pat. No. 5,990,065 also describes a hand dishwashing detergent comprising low molecular weight diamines. However, this invention requires the addition of magnesium and/or calcium, which results in less stable formulations. U.S. Pat. No. 6,069,122 also describes a hand dishwashing detergent comprising low molecular weight diamines.
However, none of the above patents disclose a LDL composition comprising one or more fatty amine derivatives selected from the group described herein and about 5% to about 50%, by weight, of an anionic base surfactant formulation, wherein the anionic base surfactant formulation comprises an alkylbenzene sulfonate having a C6-C22 alkyl group. Further, many of the prior art LDL compositions discussed above have a pH of 9 to 11, and sometimes higher, a range that may be irritating to human skin.
Thus, there remains a need for a cost effective LDL composition that can provide for the improved removal of baked-on greasy and fatty soils. A further need exits for a LDL composition effective for baked-on greasy and fatty soils which still maintains good foaming properties and which is in a pH range that is mild to human skin.
It has now been unexpectedly found that the use of certain fatty amine derivatives in conjunction with certain anionic base surfactant formulations, as described in more detail herein, leads to improved cleaning properties when compared to prior art LDL compositions, while still maintaining desirable foaming, viscosity or mildness properties.
Due to the improved cleaning abilities of the present invention, it is also possible to reduce the total surfactant content in the LDL composition described herein while still maintaining the same level of cleaning as prior art LDL compositions, resulting in significant manufacturing cost savings.
Further, the strong cleaning properties of the present LDL composition allows for the reduction or elimination of Mg/Ca ions without a detrimental effect on cleaning ability.
More particularly, the present invention relates to a light duty liquid detergent composition comprising
In another aspect, the present invention relates to a method of making a light duty liquid detergent composition which comprises the steps of:
In a still further aspect, the present invention relates to a method of removing soils from hard surfaces comprising:
The present invention still further relates to a method of washing soiled dishes or other kitchen items wherein an effective amount of the LDL composition described above is absorbed onto a cloth, sponge or similar cleaning tool; the cloth, sponge or similar cleaning tool is contacted with the surface of each soiled item; and each soiled item is rinsed in water. By “effective amount” is meant an amount sufficient to remove enough soil from the surface of the item for the user to determine the item has been adequately cleaned, as based on the habits and practices of the user.
The present invention additionally relates to a method of washing soiled items wherein an effective amount for cleaning of the LDL composition of the present invention is diluted in water to form a diluted solution and each of the soiled items are either immersed in the diluted solution and cleaned by contacting the surface of each of the soiled items with a cloth, sponge or similar cleaning tool; or a method by which a cleaning effective amount of the LDL composition of the present invention is diluted in water to form a diluted solution and a cloth sponge or similar cleaning tool is first immersed in the diluted solution and then the cloth sponge or similar cleaning tool is contacted with the surface of each of the soiled items. By “effective amount” is meant an amount sufficient to remove enough soil from the surface of the item for the user to determine the item has been adequately cleaned, as based on the habits and practices of the user.
Additional objects, advantages and novel features will be apparent to those skilled in the art upon examination of the description that follows.
All parts, percentages and ratios used herein are expressed as percent weight unless otherwise specified.
The present invention utilizes an anionic base surfactant formulation comprising at least one alkylbenzene sulfonate having a C6-C22 alkyl group. Other anionic surfactants, for example, alfa olefin sulfonates (AOS), paraffin sulfonates (PS), secondary alkane sulfonates (SAS), fatty alcohol sulfate (FAS), sulfonated fatty acids or their esters, or mixtures thereof, may also be utilized as part of the anionic base surfactant formulation of the present invention to further enhance the cleaning or other properties of the LDL. However, the addition of ether sulfates may have an antagonistic effect on the degreasing ability of the alkylbenzene sulfonate and, preferably, the present LDL composition is substantially free of ether sulfate.
Preferably, the anionic surfactant base formulation is present in an amount equal to about 5% to about 50% and more preferably, about 7% to about 30%. The alkylbenzene sulfonate may be either linear or branched and can be in the form of a sodium, magnesium, isopropylamine, triethanolamine, or calcium salt. In one preferred embodiment of the present invention, the alkylbenzene sulfonate is linear dodecylbenzene sulfonate in either magnesium or sodium form.
Secondary surfactants, either anionic or nonionic, may also be added to the LDL composition of the present invention. These secondary surfactants are not part of the base surfactant formulation and are added for a variety of other enhancing reasons including improved mildness to the skin, foam boosting, foam stabilization, and viscosity modification. For example, alkylbenzene sulfonates have a less desirable foaming profile when used with hard water and are also known to remove fat from the skin, leaving it dry with a tendency to crack. Typically, secondary surfactants would be added to the LDL in order to reduce the de-fatting effect and to provide foam boosting in hard water. Examples of suitable secondary surfactants include betaines, alkanolamides, amine oxides, alkylpolyglucosides, fatty acid glucamide, and fatty alkanol amides. However, amine oxides may have an antagonistic effect on the degreasing ability of the alkylbenzene sulfonate and, preferably, the present LDL composition is substantially free of amine oxide.
The present invention further comprises at least one fatty amine derivative selected from the group consisting of:
The addition of one or more of the fatty amine derivatives described herein has surprisingly been found to synergistically boost the effectiveness of the alkylbenzene sulfonate to remove greasy or baked on soils. Preferably, the fatty amine derivative(s) is or are present in the LDL composition in an amount equal to about 0.1% to about 10%, more preferably in an amount equal to about 0.1% and about 5%, and most preferably in an amount equal to about 0.1% to about 2%.
If either ether sulfate or amine oxide or both are added to a LDL composition in accordance with the present invention, the amount of fatty amine derivative may be increased to counteract any antagonistic effect these surfactants may have on the ability of the alkylbenzene sulfonate to remove baked-on soil in order to achieve a cleaning performance equal to the LDL composition prior to the addition of ether sulfate or amine oxide or both.
The benefits of including an inorganic or organic salt or oxide of a multivalent cation, particularly magnesium and calcium ions, in LDL compositions is well known in the art. However, it is equally well known that the total amount of magnesium or calcium ions used in such compositions should be limited as these ions can often cause formulation difficulties. For example, typical magnesium ion content in a commercial LDL product varies from 0.04-0.4%. In addition to providing enhanced cleaning, the addition of the fatty amine derivatives with the anionic surfactant base formulation as described herein unexpectedly allows for effective cleaning without the inclusion of such ions. However, if desirable, these ions may still be included in the LDL composition of the present invention to further enhance the cleaning properties with the added benefit that there can be a reduction in the amount of the ions utilized in the LDL composition without any corresponding loss in cleaning effectiveness when compared to currently available LDL compositions. If such ions are added, preferably magnesium ions are utilized. In one preferred embodiment of the present invention, magnesium ions are added at levels of about 0.04% to about 0.25%. Examples of suitable sources of magnesium or calcium ions include salts such as chlorides, sulfates, acetates, sulfides, hydroxides or counter ions of surfactants such as ether sulfates, alkylbenzene sulfates, alkanolamides or combinations thereof.
Hydrotroping and coupling agents may optionally be included in the composition of the present invention to increase the solubility of the surfactants contained therein. Examples of suitable hydrotroping and coupling agents for use with the present invention include sodium xylene sulfonate, sodium cumene sulfonate, sodium toluene sulfonate, ethanol, isopropanol, propylene glycol, polyethylene glycol or mixtures thereof.
Buffering and neutralization agents may also be optionally added to the described composition to neutralize the alkylbenzene sulfonic acids and to adjust the formulation pH to optimize cleaning performance or to adjust the pH to a range considered milder to human skin. Examples of suitable buffering and neutralization agents for use in the present invention include urea, ammonia, sodium hydroxide, potassium hydroxide, citric acid, sulfuric acid, hydrochloric acid, alkanolamines, and ethanolamine. It is preferred for the pH of the present invention to be about 5 to about 12. More preferably, the pH of the present invention is about 7.5 to about 9.5.
In addition to the above described components, the present invention may optionally and preferably does contain one or more adjunct ingredients that serve to improve overall product performance and appearance. These include dyes, preservatives, fragrances, chelating agents, solubilizers, soil release polymers, anti-irritants, dispersants, thickeners, bactericides, antifungal agents, brighteners, enzymes, abrasives, and anti-corrosive aids. Any conventional adjunct ingredients known in the art are suitable for use herein. Examples of suitable preservatives include formaldehyde, glutaraldehyde, ethanol, benzoic acid, kathon, dowicil, bronopol, and hydroxybenzoic acid. Alcohol ethoxylates and fatty acid ethoxylates may also be added as adjuncts in order to provide additional cleaning performance.
When producing the LDL composition of the present invention, the improved cleaning performance is demonstrated only when the components are added in particular sequence. More specifically, the fatty amine derivative cannot be added as part of the neutralization package (i.e., with the neutralization agent). In one preferred method for producing the present invention, at least one neutralization agent is first added to water to form a solution. An alkylbenzene sulfonic acid having a C6-C22 alkyl group is added to the solution. If either ethoxylated ether sulfate or ethoxylated amides are utilized, these components must only be added when the solution is at approximately pH 6 or greater, as the ethoxylated ether sulfate will immediately hydrolyze at lower pH values. Buffering agents may need to be added prior to these components in order to adjust the pH to an appropriate value. Optional additional components, such as magnesium or calcium ions, hydrotropes, foam stabilizing agents, or buffering agents are added next. Any adjuncts being utilized, such those described above, are also added at this time. Then, one or more fatty amine derivatives are added. Finally, minor adjustments are made for viscosity and pH.
The present invention maintains its improved cleaning abilities when utilized in a variety of consumer washing methods. These methods include, for example, the following typical consumer practices:
The following examples illustrate the light duty liquid compositions of the described invention. These examples are illustrative and do not limit the scope of the invention. In all examples, ceramic tiles were soiled with common kitchen type soils such as lard, oil, flour, and milk and baked. The percent of soil removal was determined through spectrophotometer readings both before and after a mechanical scrub test was performed.
The following light duty liquid compositions were prepared:
Approximately 2 weight % of a neutralizing agent, e.g., sodium hydroxide, was added to water. Dodecylbenzene sulfonic acid was slowly added until completely in solution. The other ingredients shown above were added in the order listed. Adjustments to the viscosity were made by using sodium xylene sulfonate in the above formulations until the final viscosity was between 300-400 cps. The pH was checked and adjusted where required.
As shown in Example 1, the capacity of the base formulation A to remove baked kitchen grease is very limited between ph 6-9, but increases by 20% when the formulation pH is 10 and above. No further increase is seen at higher pH values. The addition of 1% ethoxylated (2) tallowalkylamine in formula C in accordance with the present invention resulted in a 40% increase. Further increase in ethylene oxide content of the fatty amine derivative did not show the same boost in removal of baked on kitchen soil.
The following light duty liquid compositions were prepared:
Approximately 2 weight % of a neutralizing agent, e.g. sodium hydroxide was added to water. Dodecylbenzene sulfonic acid was added until completely solublized. The remaining ingredients were then added in the order listed above. Viscosity was adjusted by using sodium xylene sulfonate until a final viscosity between 300-400 cps was achieved. The pH was checked and, if needed, was adjusted to approximately 8.5.
As can be seen in example 2, the addition of magnesium ions to a dodecybenzene sulfonate formula results a dramatic increase in cleaning. At a 0.3% level of magnesium ions with DDBSA the removal of soil is significant, but drops by 20% when the magnesium is decreased to 0.15%. A further decrease is seen when a sodium laureth (2) sulfate is added to the formulation. However, the addition of 1% fatty amine derivative to each formulation as described in the present invention results in a statistically significant increase in soil removal, even with 0.3% Magnesium ions. As can be seen in formula L above, no cleaning occurs with just the fatty amine derivative alone.
The following light duty liquid compositions are made:
Approximately 2 weight % of sodium hydroxide was added to water. Dodecylbenzene sulfonic acid was added slowly until completely in solution. The other ingredients set forth above were added in the order of listed. Viscosity was adjusted by using sodium xylene sulfonate in the above formulations until final viscosity between 300-400cps was achieved. The pH was checked and, if needed, adjusted to approximately 8.5.
The reduction of Magnesium to 0.06% and an increase in sodium laureth (3) sulfate shows a further lowering of the cleaning performance as compared to formula H in example 2. The addition of the fatty amine derivative to Formula M in accordance with the present invention results in a significant increase in the removal of the baked-on kitchen soil.
Formulation P was prepared using the same components and in the same amounts as for formulation O in example 3, except that the fatty amine derivative was added as part of the neutralization package.
As shown above, there is a significant drop in cleaning when formula P is compared with formula O in example 3.
Fatty amine derivatives were added to a commercial LDL formulation based on the following ingredients: sodium laureth sulfate, sodium dodecylbenzene sulfonate, amine oxide, sulfonated methylesters, plus other minor ingredients. The formula has a Magnesium ion content of about 0.36%.
Formulations S through X, all show a significantly increase in the removed of the baked on kitchen soil with the addition of the various fatty amine derivatives as described herein.