US3211661A - Liquid detergent composition - Google Patents

Abstract

Compounds of unknown structure, referred to as "primary sultaines," are obtained by refluxing equimolar amounts of a C10-14-straight chain primary alkyl amine and a C3-4-sultone in acetone solution. The "sultaine" precipitates out and may be recrystallized from acetone. In the example, the "sultaine" is obtained from propane sultone and an amine having an alkyl chain consisting predominantly of C12 and C14 chains. The "sultaines" are used as detergent builders (see Division C5).ALSO:A liquid detergent composition comprises, by weight, (a) 15-35% of a detergent of formula R(OC2H4)xSO4M wherein R is a straight-chain C10- 14-alkyl group of which at least 50% have 12 carbon atoms, x is 0-4, and M is sodium, potassium, ammonium or triethanolammonium; (b) 3-8% of the reaction product of a straight-chain C10- 14-alkyl primary amine (at least 50% of the alkyl groups having 12 carbon atoms) and a C3- 4-sultone (see Division C2); and (c) 10-25% of a C1- 3-alkanol, preferably ethanol; the ratio (a):(b) being 3-6: 1 and the total of (a) and (b) being 20-40%. Generally up to 5% of sodium, potassium or ammonium toluene or xylene sulphonate may be present and the balance of the composition consists of water; (a) is preferably the sodium or ammonium salt of the sulphated condensate from 1 mole middle cut coconut alcohol and 3 moles ethylene oxide. Up to 12% of inorganic salt impurities, up to 3% of opacifiers such as ethylene glycol distearate or polystyrene, and perfume and colour may also be incorporated.

Description

United States Patent 3 211 661 LIQUID DETERGEfitT COMPOSITION Norman Rex Smith, Cincinnati, Ohio, assignor to The Procter & Gamble Company, Cincinnati, Ohio, a cororation of Ohio l lo Drawing. Filed Dec. 15, 1961, Ser. No. 159,770 3 Claims. (Cl. 252-153) This invention relates to detergent compositions in liquid form. It comprises unbuilt mixtures of surface active detergent compounds having exceptional sudsing ability.

The quantity and persistence of suds are very important in a light duty liquid detergent which will 'be used for dishwashing and the like. The user is accustomed to gauging the detergency capacity of a washing solution by the amount of suds present and will very likely be misled if the suds do not persist for a reasonable period of time.

There are many difiiculties associated with formulating a high-sudsing, light-duty liquid detergent. An ideal liquid detergent composition is clear and colorless, permitting the formulation of a wide variety of opaque, clear, colorless, and colored detergents. However, the most common suds builders for such products are fatty acid amides, which tend to color the product yellow. An ideal liquid detergent is also one where the major ingredients are highly compatible with each other so that only a minimum amount of solubilizing agent is needed to keep the detergent in a single phase, yet many detergent surface active agents and suds builders are not unlimitedly soluble in water, especially in combination with each other. Products containing fatty acid amides are especially subject to phase separation as a result of exposure to low temperatures (poor freeze resistance) and therefore require considerable amounts of a solubilizing agent such as ethyl alcohol or sodium toluene sulfonate. Furthermore, the ideal liquid detergent weould be suitable for effective and high sudsing use with all kinds of soil and wash water, including acidic soil and wash water.

Accordingly, it is an object of this invention to provide a high-sudsing, light-duty liquid detergent.

It is a further object of this invention to provide a highsudsing, light-duty liquid detergent which maintains as much as possible its sudsing performance under acid conditions.

It is a still further object of this invention to provide a high-sudsing, light-duty liquid detergent which does not need an amide-type suds builder.

It is another object of this invention to provide a single-phase, high'sudsing, light-duty liquid detergent requiring only a relatively small amount of a solubilizing agent.

The unbuilt, high-sudsing, light-duty liquid detergent compositions of this invention consist essentially of: (1) from about to about 35% by weight of the composition of a sulfate detergent surfactant having the following formula wherein R is a straight chain alkyl group having from. about 10m about 14 carbon atoms with at least 50% of said alkyl groups having 12 carbon atoms, x is a number from zero to about four, and Me is selected from the group consisting of sodium, potassium, ammonium, and triethanolammonium cations; (2) from about 3% to about 8% by weight of the composition of the reaction product of a primary amine having a straight chain alkyl group having from 10 to 14 carbon atoms with at least 50% of said alkyl groups having 12 carbon atoms and a sultone having from 3 to 4 carbon atoms; (3) from about 10% to about by weight of the composition of a solubilizing agent selected from the group consisting of methyl, ethyl, and propyl alcohols; and (4) the balance water. Minor ingredients including up to about 5% y weight of the composition of a viscosity control agent such as either potassium, sodium, or ammonium toluene sulfonate or potassium, sodium or ammonium xylene sulfonate, and mixtures thereof; perfume; opacifiers; and coloring can be added if desired but are not necessary.

It has been discovered that the reaction product of primary amine and sultone hereinbefore described and hereinafter referred to as primary sultaine Will build (enhance) the sudsing ability of the sulfates of this invention to a high degree, but do not build the s'udsing ability of sulfonates, o1 sulfate surfactants containing aromatic configurations to the extent desired in light duty detergents having a pH in the range of about 6.5 to about 9.5. As used herein, sudsing ability refers to both the initial quantity of suds and the persistence of the suds throughout the washing operation. The persistence (stability) of the suds of the compositions of this invention is extremely good under alkaline, neutral, and acidic conditions. It has also been discovered that unless the weight ratio of sulfate detergent surfactant to primary sultaine is above about 3/1, the composition is not a stable, single-phase system. On the other hand, if this ratio is more than about 6/1, the suds building ability of the primary sultaine is not adequately realized. The total amount of both sulfate detergent surfactant and primary sultaine should not be more than about 40% by weight of the composition in order to insure formation of a stable, single-phase system; but the total amount should be more than about 20% by weight of the composition to provide sufiicient suds and detergency.

The concentration range of the sulfate detergent agent is set at the lower limit of 15% by weight of the composition by sudsing considerations and at the upper limit of 35% by weight of the composition by viscosity consideratrons. At lower levels the quantity of suds is drastically reduced and at higher levels the products is no longer pourable.

Both the sulfate detergent and the primary sultaine have certain requirementsas to structure. The alkyl chain lengths in both should not be less than ten carbon atoms since compounds having shorter chain lengths give reduced detergency. Similarly, the alkyl chain lengths should not be greater than 14 since compounds having longer chain lengths produce reduced quantities of suds. The requirement that at least of the alkyl chains in both of the compounds contain 12 carbon atoms is determined by the above considerations of sudsing and detergency since this is the optimum chain length. A desirable alkyl chain length distribution is obtained from the middle out of distilled coconut fatty alcohol as more fully described in Example I.

A sulfate detergent containing no ethylene oxide groups is an effective detergent and sudser, but is not quite as mild as a. sulfate detergent surfactant containing these groups. However, a sulfate detergent with more than about four ethylene oxide groups in the molecule has substantially reduced sudsing capacity.

The preferred sulfate detergent surfactant contains an average of three ethylene oxide groups per molecule. In general, all of the compositions of this invention are mild when applied to human skin.

The swltones used in preparing the primary sultaines of this invention contain carbon chains of either three or four carbon atoms and have the following general formula:

RS=O

0 wherein R is a carbon chain of either four or three carbon atoms. Su-ltones with less than three carbon atoms are not available and reaction products prepared with sultones having more than four carbon atoms are less effective with respect to suds building ability both as to quantity and stability, but primarily with respect to quantity. The preparation of such reaction products can be accomplished by reacting equimolar quantities of the primary amine and the sultone in acetone while refluxing at the boiling point of acetone. The precipitate which forms can then be recrystallized from acetone if desired. The structure of this reaction product is not known and consequently the product can only be described in terms of the reaction.

The finished detergent compositions of this invention require the addition of a solubilizing agent to prevent phase separation Although much less solubilizer is needed in the compositions of this invention than in those which use an amide suds builder, still at least about 10% of the solubilizing agent is necessary. Too much solubilizing agent would be costly and might adversely affect viscosity, so that preferably only enough solubilizing agent is included in the composition to keep the composition in a pourable single phase under conditions of use, but not more than about 25% by weight of the composition.

As hereinbefore mentioned, various minor ingredients including perfume, viscosity control agents, opacifiers, and coloring can be added. Inert materials such as water-soluble inorganic salts may also be present in amounts up to about 12% by weight of the composition, generally as impurities from the various other ingredients or as opacifier stabilizers.

Potassium toluene sulfonate, as a viscosity control agent, is a desirable minor additive in amounts up to It increases the viscosity of the compositions. sirable additives include opacifiers such as ethylene glycol distearate or polystyrene in amounts up to about 3% by weight of the composition.

The compositions of this invention need not contain conventional suds builders such as fatty acid amides. The superior sudsing ability of these compositions makes it unnecessary to have such suds builders present, which results in cost advantages and simplified formulation.

' Also, the compositions of this invention have better odor Other de-' product of a primary amine having a carbon chain length distribution of C10, C12, C14, and C16, anda propane sultone, the primary sultaine being prepared by reacting equimolar quantities of amine and sultone in acetone solution while refluxing at the boiling point of acetone, and recrystallizing the resulting precipitate from acetone. Each composition also contained 10% ethyl alcohol. Diiferent detergent surfactants were added to these compositions in varying amounts. Detergent surfactant A was the ammonium salt of the su-lf ated condensation product of middle-cut coconut alcohol, containing approximately 2% C 66% C 23% C and 9% C of alkyl groups, with three moles of ethylene oxide (NH AE S). Detergent surfactant B was the sodium salt of tetrapropylene benzene sulfonate (NaABS) Detergent surfiactant C was the sodium salt of the sulfated condensation product of A (NaAE S). Detergent surfactant D was the ammonium salt of the sulf-ated condensation product of tetnapropylene phenol and four moles of ethylene oxide (NH APE S). The balance of each composition was water. All percentages contained herein are by weight of the composition.

The stability of each composition was observed and is reported below.

In order to evaluate the sudsing ability of these compositions, 7.25 cc. of each of the compositions was added to a dishpan containing one gallon of water with a hardness of 7 grains, a temperature of 115 F., and a pH of 7. Suds were generated by mechanical agitation (small propeller) and the suds level measured. A fixed quantity (about 5 grams) of standardized fatty soil (a triglyceride shortening) was placed on a dinner plate which was then washed in the test solution. The plate was re-soiled and washed, repeating this procedure a total of five times. Five additional sets of five soiled plates were washed in the solution in like manner, measuring the foam height after each set. The foam height after washing each set was expressed in terms of percent of original suds height and an average of the five percentage values was computed and is reported below.

A difference of about 5% in foam height is considered significant and noticeable by the housewife. It will be understood that the compositions of this invention are not distinguished from compositions outside the scope of the invention by virtue of being the only operable combinations, but uather by the exceptional improvement in performance effected by the compositions of this invention.

- Composition 1 2 3 4 5 6 7 8 9 Percent Primary Sultainp 25 6.7 Percent A NH4AE;S i 8.3 25. Percent B NaABS Percent C NaAE S Percent D NH4APE4S. Ethyl Alcohol; 10 10. 10. Water Bal Bal Bal B'r11 B941 B81... B31... Bal Bal. Sudsing Performance at pH 7 No suds Not enough 37 33 N ough 2 30 32 18.

- suds to suds to measure. measure. I Stability of the Liquid Compositiom-.. Solidified Solidified- Solid1fied. Unstable l Separated into at least two phases. 2 Stable one phase system.

corrected by adding much more solubilizing agent than is ordinarily required in compositions of this invention.

I The compositions of this invention have improved freeze resistance as compared with compositions containing amides.

The following examples will demonstrate the unique advantages of the compositions of this invention as opposed to compositions outside the scope of this invention.

I Example I The following compositions (with the exception of As can be seen from the performance of these compositions neither all primary sultaine (Composition 1) nor all alkyl ethylene oxide sulfate (Composition '9) forms a good sudsing product when used alone, but when these materials are used together as in Compositions 6 Composition 9) contained varying amounts of the reaction outstanding liquid products of this invention.

When opacifiers such as ethylene glycol distearate, and/or as much as 5% of either sodium, potassium, or ammonium toluene sulfonate or sodium, potassium, or ammonium Xylene sulfonate, and mixtures thereof (as viscosity control agents) are added to the Compositions 6 and 8, substantially equivalent results are obtained. When alkyl sulfates and alkyl ethylene oxide sulfates having different numbers of ethylene oxide groups, on the average, in the molecule are substituted for the alkyl ethylene oxide sulfates of Compositions 6 and 8, substantially equivalent results are obtained. Similarly when the corresponding potassium or triethanolammonium salts are substituted for the sulfate detergent surfactants of Compositions 6 and 8, substantially equivalent results are obtained. Also, when the ethyl alcohol in these compositions is replaced by either methyl or propyl alcohols equivalent results are achieved. Addition of coloring and perfume to these compositions does not affect the results obtained.

What is claimed is:

1. A high-sudsing, light-duty liquid detergent composition consisting essentially of (1) from about 15% to about 35% by weight of the composition of a sulfate detergent having the following formula wherein R represents straight chain alkyl groups having from about to about 14 carbon atoms with at least 50% of said alkyl groups having 12 carbon atoms, x is a number from 0 to about 4, and Me is selected from the group consisting of sodium, potassium, ammonium, and triethanol ammonium cations; (2) from about 3% to about 8% by weight of the composition of the reaction product of a primary amine having a straight chain alkyl group having from 10 to 14 carbon atoms with at least 50% of said alkyl groups having 12 carbon atoms and a sultone having from 3 to 4 carbon atoms, said reaction product corresponding to that prepared by reacting equimolar quantities of said amine and said sultone in acetone solution While refluxing at the boiling point of acetone; (3) from about 10% to about 25% of a solubilizing agent selected from the group consisting of methyl, ethyl, and propyl alcohols; and (4) the balance Water, the ratio of (1) to (2) being above about 3/1 and not more than about 6/ 1, and the total of (l) and (2) being more than about 20% by weight of the composition and not more than about by weight of the composition.

2. The composition of claim 1 containing, as an additional ingredient, a viscosity control agent selected from the group consisting of sodium, potassium, and ammonium toluene sulfonates, sodium, potassium, and ammonium Xylene sulfonates, and mixtures thereof in an amount up to about five percent by weight of the composition.

3. The composition of claim 1 wherein the sulfate detergent is the ammonium salt of the sulfated condensation product of one mole of middle-cut coconut alcohol and three moles of ethylene oxide.

References Cited by the Examiner UNITED STATES PATENTS 1,944,300 1/34 Ott et a1 260513 2,673,842 3/54 Brown 252-355 XR 2,809,973 10/57 Gaertner 252-355 XR 2,941,950 6/60 Korpi et a1. 252-153 2,970,963 2/61 Walker et al. 252153 FOREIGN PATENTS 1,018,421 10/57 Germany.

JULIUS GREENWALD, Primary Examiner.

Claims (1)

1. A HIGH-SUDSING, LIGHT-DUTY LIQUID DETERGENT COMPOSITION CONSISTING ESSENTIALLY OF (1) FROM ABOUT 15% TO ABOUT 35% BY WEIGHT OF THE COMPOSITION OF A SULFATE DETERGENT HAVING THE FOLLOWING FORMULA