US3813349A - Liquid detergent composition - Google Patents

Abstract

DISCLOSED HEREIN ARE STABLE TWO-PHASE LIQUID DETERGENT EMULSIONS THAT MAINTAIN STABILITY WITHOUT THE USE OF ADDITIONAL STABILIZING AGENTS. THESE AUTOSTABILIZED EMULSIONS ARE MADE UP OF ANIONIC, ZWITTERIONIC OR SIMIPOLAR COMPOUNDS, ELECTROLLYTES, ALCOHOLS AND WATER. AUTOSTABILIZED EMULSIONS ARE CAPABLE OF SUPPORTING WATER-INSOLUBLE PARTICULATE MATERIAL.

Description

United States Patent Oflice 3,813,349 Patented May 28, 1974 US. Cl. 252-526 2 Claims ABSTRACT OF THE DISCLOSURE Disclosed herein are stable two-phase liquid detergent emulsions that maintain stability without the use of additional stabilizing agents. These autostabilized emulsions are made up of anionic, zwitterionic or simipolar compounds, electrolytes, alcohols and water. Autostabilized emulsions are capable of supporting water-insoluble particulate material.

This is a continuation of application Ser. No. 888,862, filed Dec. 29, 1969, and now abandoned.

BACKGROUND OF THE INVENTION There is an ever increasing demand for liquid detergent compositions that are useful as, e.g., liquid scouring cleanser compositions or as liquid abrasive cleaner compositions. These liquid detergent cleaning compositions are provided in a convenient form. The compositions of this invention are especially formulated for the above expressed cleaning applications.

To obtain optimum cleaning ability and wide consumer acceptance, detergent compositions of this invention must be homogeneous and easily pourable. The above compositions should maintain their homogeneity during ordinary periods of storage and use. It is highly desirable that the formulation of the invetnion exhibits Bingham plastic characteristics, i.e., exhibit a substantial yield value to keep the particulate materials suspended.

This invention relates to the formulation of stable two phase liquid detergent emulsions, called autostabilized emulsions, capable of supporting water-insoluble particulates which have utility as, e.g., hard surface cleaners. Autostabilized emulsions can be formed without the use of additional stabilizing agents. Due to the addition of alcohol, the autostabilized emulsions can support higher electrolyte levels than previously known two-phase emulsion compositions, making the autostabilized emulsions much more desirable as, e.g., hard surface cleaners.

SUMMARY OF THE INVENTION The formulations of this invention, having the abovedescribed utility, are novel, stable two-phase liquid detergent emulsions, referred to as autostabilized emulsions.

An object of this invention is to formulate autostabilized two-phase liquid detergent emulsions, i.e., emulsions that are stabilized without the use of hydrotropes or other stabilizing agents, capable of supporting water-insoluble particulates.

A further object of this invention is to formulate autostabilized emulsions that are useful, e.g., in liquid scouring cleanser compositions or as liquid abrasive cleaner compositions.

THE PRIOR ART Many of the components used in the present invention are well known in combination in the detergent art on two-phase liquid detergent emulsions. This is pointed out in U.S. Pats. 2,999,068, 3,232,878 and 3,281,267.

In US. Pats. 3,272,753, 3,332,875, 3,179,599, 3,035,- 982 and 3,179,598, the use of ethanol in various liquid detergent compositions is disclosed. Ethanol, as used in the art, is a solvent that allows the combination of components in a more stable solution. The art does not suggest that as an additive ethanol allows an increase in electrolyte content of an already stable two-phase emulsion as in the present invention. Thus, although the art teaches some stable two-phase emulsions with various components that are similar to those used in the present invention, the art fails to each the present invention which contains very specific components and composition ranges and which provides for autostabilized two-phase emulsions capable of supporting water-insoluble particulate material and unexpectedly large additions of electrolyte for use in, e.g., liquid scouring cleanser compositions and liquid abrasive cleaner compositions.

DETAILED DESCRIPTION OF THE INVENTION The liquid detergent compositions of this invention are autostabilized, two-phase, liquid detergent emulsions capable of supporting water-insoluble particulate material, said autostabilized emulsions consisting essentially of:

(1) from about 4% to about 28% by weight of:

(a) an anionic synthetic detergent surfactant having the general formula wherein R and R are staight chain alkyl radicals containing from about 10 to about 16 carbon atoms and M is a cation selected from the group consisting of potassium, sodium, ammonium, monoethanolammonium, diethanolammonium, and triethanolammonium cations; and

(b) a zwitterionic quaternary ammonio synthetic detergent surfactant having the general formula wherein R is an alkyl radical containing from about 10 to about 16 carbon atoms, and R is selected from the group consisting of hydrogen and hydroxyl; or (c) a semipolar surfactant having the general formula wherein the ratio of zwitterionic or semipolar to anionic surfactants is from about 2:1 to about 1:3.

The individual components of the autostabilized emulsions of this invention are anionic detergent, semipolar detergent or zwitterionic synthetic detergent, electrolyte, alcohol and water. Optional components include minor ingredients which have aesthetic value or which improve the effectiveness of the autostabiilzed emulsions. As a preferred embodiment, insoluble particulate material can be added to the autostabiized emulsions of this invention, since all of the autostabilized emulsions of this invention are capable of suspending insoluble particulate materials.

In the autostabilized emulsions of this emulsion, it has been discovered that the surfactants must be a mixture of a semipolar or zwitterionic surfactant with an anionic surfactant in specific proportions, i.e., a ratio of about 2:1 to about 1:3 respectively and in a specific amount, i.e., from about 4% to about 28% by weight of the autostabilized emulsion compositions. Anionic surfactants and zwitterionic or semipolar surfactants, when used separately, will not provide a stable support for insoluble particulate materials. However, when they are used together as specified below, they unexpectedly cooperate to provide a stable medium with a yield value that will support insoluble particulate material.

The total amount of zwitterionic or semipolar and anionic surfactants, i.e., from about 4% to about 28% by weight of the composition, and the relative amount in which the above surfactants are present in the autostabilized emulsion compositions of this invention, i.e., a ratio of zwitterionic or semipolar to anionic surfactant of about 2:1 to about 1:3, is more important in the practice of this invention than the exact amount of each surfactant in the autostabilized emulsions.

While the exact amount of each detergent surfactant is of little significance, the total amount of the surfactants is important. The total amount of surfactant used in an autostabilized emulsion determines the yield value and the ability to dissolve grease and dirt. If there is an excessive amount of total surfactant present in the autostabilized emulsion, i.e., above about 28% by weight of the composition, the autostabilized emulsion becomes too thick and unmanageable.

The relative amount of zwitterionic or semipolar to anionic detergent surfactants, i.e., a weight ratio of zwitterionic or semipolar to anionic surfactant, sharply affects the ability of the auto stabilized emulsion to support insoluble particulate material. When the ratio of zwitterionic or semipolar to anionic surfactant falls within the proper relative amount, i.e., a ratio of about 2: 1 to about 1:3, the autostabilized emulsions of this invention have excellent yield values, and they maintain phase stability. It is preferred that the ratio of zwitterionic or semipolar to anionic surfactant be about 1:1. The exact value of this ratio depends on other materials present in the autostabilized emulsions.

It has been discovered that only certain members of each class are functional. Two anionic detergnts provide the necessary emulsion stability; these detergents are alkyl glyceryl ether sulfonate and alkylbenzene sulfonate. Two zwitterionic synthetic detergents provide the necessary emulsion stability; these detergents are hydroxy ammonio propane sulfonate and ammonio propane sulfonate. One semipolar detergent alternatively provides the necessary emulsion stability; this is alkyldimethylamine oxide. The semipolar detergent, i.e., al kylidimethylamine oxide is more preferred over the zwitterionic detergents in combination with the other components of the autostabilized emulsions of this invention.

From about 10% to about 20% of the finished composition is polyvalent electrolyte or builder. Only the addition of a lower alcohol containing 1 to about 5 carbon atoms, preferably ethanol, in an amount from about 2% to about 9%, preferably about 5%, allows this relatively high amount of electrolyte to be used with no effect on stability. The preferred amount of electrolyte as used in the compositions of this invention is about 15% by weight of the composition. This increase in electrolyte content assists in maximizing stability and increasing the cleaning characteristics of the autostabilized emulsion. Various electrolytes can be used, e.g., tetrapotassium 4 pyrophosphate, nitrolotriacetate and ethane-l-hydroxy- 1,1-diphosphonate.

Tetrapotassium pyrophosphate is preferred to other electrolytes because of its good cleaning characteristics and excellent solubility characteristics. The liquid detergent compositions built with tetrapotassiurn pyrophos phate also exhibit excellent stability characteristics over a wide range of temperatures.

Although other electrolytes may be used, their operating region in which phase stability is maintained is relatively small. The operating region varies for each specific combination of components. The addition of lower alcohols by expanding the operating region of autostabilized emulsions allows the addition of higher levels of electrolyte without the normally resulting instability that occurs if higher amounts of builder are added Without the lower alcohol. In previous compositions, only from 1% to 10% electrolyte could be used if stability was to be maintained. In this invention, with lower alcohol addition, 10% to 20% is used making autostabilized emulsions more effective as, e.g., hard surface cleaners. An operating region in the range wherein the different components in the autostabilized emulsion can be used in various amounts and phase stability is still maintained.

The balance of the composition is water. It is preferred that from about 30% to about 50% by weight of the finished composition be water when the insoluble particulate material is added to the autostabilized emulsions to optimize yield values and cleaning characteristics of the finished product. The pH of the compositions is in the range from about 7 to about 12, preferably from about 9 to about 11.

In the practice of this invention, from 5% to about 75% of the composition can be insoluble particulate material. It is preferred, however, that from about 40% to about 50% by weight of the finished composition be insoluble particulate material.

Within the preferred range of insoluble particulate material (about 40% to about 50% it is preferred that about 4% to about 20% of the supporting medium be detergent surfactants. At higher than the specified detergent concentrations, the combined detergent and insoluble particulate materials make the compositions too thick to be manageable; at lower than the specified detergent concentrations there is not enough detergent to provide sufficient yield value to support the insoluble particulate material. The upper limit on combined detergent and insoluble particulate material is a functional one, and is best expressed in terms of apparent viscosity. The detergent compositions of the preferred embodiment of this invention must have apparent viscosity below about 12,000 centipoises. It is preferred that the apparent viscosity be below about 10,000 centipoises. As used herein and elsewhere in this specification, apparent viscosity means the value obtained with a Brookfield viscometer, Model LVF, using spindle number 3 at 12 r.p.m. At lower (below 40%) insoluble particulate material concentrations, the concentration of total detergent in the supporting medium becomes less important.

The insoluble, particulate material which can be utilized in this invention can comprise abrasives, bactericides, or other insoluble particulate material having a particle size diameter ranging from about 1 to about 200 microns and a density of from about 0.5 to about 5.0. It is preferred that the diameter of the particles range from about 2 microns to about 60 microns and that the density range from about 1.0 to about 2.8. The insoluble particulate materials which can be utilized in this invention include, but are not limited to, quartz, pumice, pumicite, talc, silica, sand, calcium carbonate, china clay, zirconinum silicate, bentonite, diatomaceous earth, whiting, feldspar, and aluminum oxide. Silica is the preferred insoluble particulate material for use herein.

Minor amounts of materials which make the composition of this invention more attractive or more effective can be added, e.g., soluble sodium carboxymethylcellulose, tarnish inhibitors such as benzotriazole or ethylenethiourea, brighteners, bleaches, fiuorescers, dyes, bluing agents, perfumes, bactericides and corrosion inhibitors,

it contains upwards of 75% of the total electrolyte. Neat is poorly conductive, more or less 3,000 ,umhos/cm. The stable emulsions have conductivities less than 25,000 pmhos/cm. instead of the greater than 80,000 mhos/cm.

if they do not significantly alter the excellent physical 5 expected for a lye continuous emulsion. Mhos/cm. properties of this composition. means micro ohms per centimeter, which is a unit of In Bingham plastics, insoluble particulate material is conductivity.) suspended because the stress imposed by the particles The following example is given additionally to illustrate does not exceed the yield value of the liquid. of course, the nature of the invention and it will be understood that if the yield value of the supporting medium should dethe invention is not limited thereto. In this example, as crease sutficiently for any reason, the particles would no in the specification, and claims, proportions indicated are longer be suspended. This could be caused, for example, percent by weight unless otherwise specified.

EXAMPLE I Percent Coconut Linear alkylcoconut Tetrapo- Total dimethylalkyltassium Phases suramine benzene pyrophos- Etha- Sample factant oxide sulfonate phate 1101 B20 Neat/Niger/Lye 1 5 3.06 1.94 10 5 Balance- X X 2 5 3.06 1.94 5 ...do.--.. X X 3... 5 3.06 1.94 5...do--.-- X X 4 10 s. 12 ass 10 5 ..do..... X X 5... 10 6.12 3.83 15 5-..do X X s... 10 6.12 3.88 20 5 ...do..... X X

by a physical or chemical change in the supporting The example shows various formulations of this inmedium, e.g., if the autostabilized emulsion settles into vention by demonstrating that stable neat-lye formulalayers upon standing, the yield value can be lost temtions remain stable with increased electrolyte addition of porarily. The original composition with its yield value up to about 20% where ethanol is added, e.g., sample can be reconstituted by mixing. If a chemical reaction number 3, shows a neat-lye emulsion with an electrolyte either consumes a vital component or produces a damcontent of 20% by weight of the composition. These aging one, the loss of yield value can be permanent. formulations were found to have excellent cleaning Hydrotropes such as sodium or potassium xylenecharacteristics and the ability to support water-insoluble sulfonate, toluenesulfonate, or benzenesulfonate, should particulates that makes them useful as, e.g., hard surnot be present in these compositions. Even very small face cleaners. More specifically, silica is added to each amounts of these hydrotropes solubilize the discrete phase of the compositions of the above example in an amount into the continuous phase. Thus, the detergent composiof 45% by weight of the compositions. The compositions tion can become a one-phase solution and loses its Bing- 0f the above example remain autostabilized emulsions and ham plastic characteristics with resultant settling of the pport the silica. insoluble particulate material. The composition, in this What is claimed is: condition, is aesthetically undesirable and not salable on All autostabilized, two-Phase ydrotropeand soapb il consumer market or h i d i l market free liquid abrasive detergent emulsion containing a mix- Also to be avoided are soaps, amides, and other matetllre Surfactants in a Proportion that coopefafivfily rials which are presently or potentially solubilizing p a Stable medium having a yield Value capable of agents, or which combine with water hardness ions. l lfp 10501111316 pflfliclllate lqatefial, Said s a- The compositions of this invention are formulated by blhzed 6111111510115 conslstlng essentlally of mixing the components together in the amounts desired. from about 4% to about 23% y Weight of a The order of mixing does not afli'ect the stability of the tllrq 0f emulsion. Any of the desired optional ingredients can then a 1111631 alkyl benzene sulphonate having the be added. general formula Ultracentrifuging is used in the following example to completely separate the phases in the autostabilized emulsions and to determine the relative proportions of the bases resent. The autostabilized emulsions all contain d a neat phase and a lye phase. The autostabilized h f IS abstralght cham alkyl radlcal emulsions are believed to be lye in neat emulsions with con almpg m 2 out 10 to 16 carbon atoms and M 18 a cation selected from the group conthe lye phase being the dispersed phase. This 1s unsisting of potassium, sodium, ammomum, expected smce the lye 15 generally q or less monoethanolammonium, diethanolammonium 75% of the total composition by volume. Evidence for and triethanolammonium cations and it thfiory 1s twofold. The r?latw.ely poor dl.spersl' (ii) a semipolar surfactant having the general bility of these autostabilized emulsions is expected if neat formula phase is continuous since the neat phase would have to go through middle phase in the process of dissolving. If the lye phase is continuous the emulsions disperse very 0 well in water. However, it is discovered that, in fact, H autostabilized emulsions have poor dispersibility. Dispersibility improves, however, as the amount of surfactant h i R i an alkyl radical containing f is lessened in the autostabilized emulsions. Thus, in the about 10 to 1 carbon atoms; practice of this invention, it has been discovered that (b) f 10% t about 20% b i h f a l emulsions maximize their dispersibility and cleaning charal nt electrolyte selected from the group consisting actefistics by the use of the Particular cQIIIPOIIGIHS and of tetrapotassium pyrophosphate, nitrilotriacetate particular proportions of each component in the autoand ethane-l-hydroxy-1,1-diphosphonate; stabilized emulsions disclosed. (2) Conductivity meas- (c) from about 2% to about 9% of a lower alcohol urements gave further evidence that the stable emulsions containing from 1 to about 5 carbon atoms; are lye in neat rather than neat in lye. Lye is very con- (d) from about 5% to about 75% by weight of an ductive greater than 100,000 ,umhos/cm. as expected since abrasive insoluble particulate material having a particle size diameter ranging from about 1 to about 200 microns and a density of from about 0.5 to about and (e) the balance being water; wherein the ratio by weight of the amine oxide to the alkyl benzene sulphonate is from about 1.6:1 to about 1:1.

2. An autostabilized, two-phase hydrotropeand soap free liquid abrasive detergent emulsion containing a mixture of surfactants in a proportion that cooperatively provides a stable medium having a yield value capable of supporting insoluble particulate material, said autostabilized emulsions consisting essentially of (a) from about 5% to about by weight of a mixture of sodium coconut linear alkyl benzene sulphonate and coconut alkyl dimethyl amine oxide, wherein the ratio by weight of said amine oxide to said alkyl benzene sulphonate is in the range of about 1.6:! to about 1.521;

(b) from about 10% to about by weight of a polyvalent electrolyte selected from the group consisting of tetrapotassium pyrophosphate, nitrilotriacetate and ethane-l-hydroxy-l,l-diphosphonate;

(c) from about 2% to about 9% of a lower alcohol containing from 1 to about 5 carbon atoms;

(d) about by weight of silica having a particle References Cited and 5 (c) the balance being water.

UNITED STATES PATENTS 2,877,188 3/1959 Kruxnrei 252-558 X 10 2,999,068 9/1961 Pilcher et a1 252-547 X 3,101,324 8/1963 Wixon 252-558 X 3,346,873 10/1967 Herrmann 252-528 X 3,392,121 7/ 1968 George 252-527 X 3,453,144 7/ 1969 Morgan et a1. 252-538 X 15 3,520,818 7/1970 Cambre 252- X 3,522,185 7/1970 Cambre 252-119 X 3,579,456 I 5/1971 Cambre 252- X 3,630,922 12/1971 McClain et a1. 252-528 X 20 LEON D. ROSDOL,

Primary Examiner H. A. PITLICK, Assistant Examiner