US3179598A - Detergent composition - Google Patents

Description

United States Patent" Ofifice s 3,179,598 Patented Apr. 20, 1955 3,179,598 DETERGENT COMPOSITION Norman Rex Smith, Cincinnati, Ohio, assignor to The Procter & Gamble Company, Cincinnati, Ohio, a corporation of Ohio No Drawing. Filed July 3, 1961, Ser. No. 121,340 2 Claims. (Cl. 252-453) This invention relates to 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 dish washing and the like. The user is accustomed to gauging the detergency capacity of a washing solution by the amount of suds present and Will be very likely be misled if the suds do not persist for a reasonable period of time. i

There are many difficulties 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 are amides, which tend to color the product yellow. An ideal liquid detergent is also one where the major ingredients are highly compatible 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. Furthermore, the ideal liquid detergent would be suitable for use with all kinds of soil and wash water, including acid 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 high-sudsing, 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 contain an amide-type suds builder.

It is another object of this invention to provide a singlephase, highsudsing, 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 20% to about 40% 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 10 to 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 monoethanolamine, diethanolamine, triethanolamine, ammonium, sodium, and potassium cations; (2) a trialkyl amine oxide having one straight chain alkyl group having from about 10 to about 14 carbon atoms with at least 50% of said alkyl groups having 12 carbon atoms and two short chain alkyl groups having from one to about two carbon atoms in an amount such that the weight ratio of sulfate detergent surfactant to amine oxide is from 3/1 to 7/1; (3) at least about by weight of the composition of a solubilizing agent selected from the group consisting of methyl, ethyl, n-propyl, and isopropyl alcohol; and (4) the balance water. Other minor ingredients including from zero to about 5% by weight of the composition of a viscosity control agent detergent compositions in such as either potassium, sodium, or ammonium toluene sulfonate or potassium, sodium, or ammonium xylene sulfonate; perfume; opacifiers; and coloring can be added.

It has been discovered that the amine oxides of this invention build (enhance) the sudsing ability of the sulfates of this invention to a high degree, but do not build the sudsing ability of sulfonates, or sulfate surfactants containing aromatic configurations to the extent desired in light duty detergents having a pH in the range of 6.5 to 9.0. 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 surfactant to amine oxide is at least 3/1, the sudsing ability of the composition is practically eliminated under acidic conditions such as might exist where the pH of the wash water was less than about 6.5. This may occur where the water itself is acid or Where the soil on the objects to be washed is acidic. On the other hand, compositions with weight ratios of sulfate surfactant to amine oxide greater than 7/1 lose sudsing ability both in acid and neutral wash water.

This loss of sudsing ability under acid conditions is ordinarily manifested only in unbuilt detergents. Whereas the pH of a liquid detergent built with substantial quantities of ordinary phosphate builders and/or silicate salts and/ or other alkaline builders is around 10 or above, the pH of the unbuilt liquid detergents of this invention and of unbuilt liquid detergents in general is about 6.5 to

9.0. In addition to this initial alkalinity in built liquids, the builder provides a reservoir of alkalinity so that there must be a considerable amount of acidic material present in the wash water before the pH will be lowered to a level where substantial loss of sudsing ability is encountered with detergent sulfate to amine oxide weight ratios outside the range of this invention. However, when only a relatively small amount of acidic material is present in the Wash Water and/or soil, the addition of unbuilt liquid detergents to the wash water will, in general, leave the wash water with an acid pH.

The concentration range of sulfate detergent surfactant is set at the lower limit of 20% by sudsing considerations and at the upper limit of 40% by viscosity considerations. At lower levels the quantity of suds is drastically re duced and at higher levels the product is no longer pourable.

The sulfate detergent surfactant itself has certain requirements as to the length of the alkyl chain. Chain lengths of less than ten carbon atoms give reduced detergency and chain lengths greater than 14 reduce the quantity of suds which are produced. Somewhat the same considerations apply also to the chain length of the long alkyl group in the amine oxide surfactant. Shorter chain lengths lead to decreased detergency, sudsing and suds building as do longer chain lengths. The upper limit on the length of the long alkyl chain in the amine oxide surfactant is especially important when the pH of the washing solution is lower than about 6.5 from the standpoints of detergency and sudsing. The requirement that the alklyl chains be at least 50% dodecyl groups is necessary in both the sulfate detergent surfactant and the amine oxide for the same reasons of sudsing and detergency mentioned above since this is the optimum chain length.

The length of the short alkyl groups in the amine oxide is set by considerations of solubility. Groups which are longer than about two carbon atoms inhibit the solubility of the amine oxide in water.

A sulfate detergent surfactant containing no ethylene many prior high sudsing compositions.

. of this invention are mild when applied to human skin.

The finished composition requires the addition of a solubiliziug agent to prevent phase separation. Although much less solubilizer is needed when an amide is not present, still at least about of the solubilizing agent is necessary. Too much solubilizing agent would be too costly and would adversely affect viscosity, so that only enough solubilizing agent should be included in the composition to keep the composition in a pourablc single phase under conditions of use, but not more than about 40% 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 is a desirable minor additive'in amounts up to 5%. It increases the viscosity of the compositions. Other desirable 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 do not contain conventional suds builders such as 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, since the most common suds builders are amides, which have odors and which color the product, the compositions of this invention have better odor and better color than Amides also tend to cause phase instability which can only be corrected by adding much more solubilizing agent than is ordinarily requiredin compositions of this invention.

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

Example I The following compositions contained varying amounts of the ammonium salt of the sulfated condensation product of middle-cut coconut alcohol containing 2%C 6*6%C 23 %-C and 9'%C alkyl groups with three moles of ethylene oxide per molecule of alcohol (A),

and a tertiary amine oxide having a long alkyl chain derived from the same middle-cut coconut alcohol and two methyl groups (B). The compositions also contained 10% ethyl alcohol and the balance water. All percentages'contained herein are by weight of the composition.

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 gallonof Water with a hardness of 7 grains, a temperature of 115 F., and pHs of 7 and 5 for two separate trials. Suds were generated by mechanical agitation (small propeller) and the suds level measured. A fixed quanity (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.

Composition 1 2 i 3 4 l 5 l 6 7 Percent A... 20 25 22. 5 24 25 24 20 Percent B 10 10 7. 5 6 5 4 2 5 10 1O 1O 1O 10 10 bal bal bal bal. bal bal bal 2. 5 3 4 5 s 8 Performance at pH 7 52 48 49 45 44 41 35 Performance at pH 5 33 33 33 34 29 1 Sudsing was too low to measure by this test method.

Compositions were prepared using the amine oxide of Example I(B) and various surface active agents. The surface active agents included:

(A) The sulfate detergent of Example I. (C) The sodium salt of'the sulfated condensation product of one mole of middle-cut coconut alcohol and three 7 moles of ethylene oxide. (D) The sodium salt of sulfonated middle-cut coconut alcohol. (E) The sodium salt of tetrapropylene benzene sulfonate. (P) The ammonium salt of the sulfated condensation product of one mole of tetrapropylene phenol and four moles of ethylene oxide. (G) The sodiumsalt of the sulfate of middle-cut coconut alcohol.

The compositions were tested as in Example I and the results are recorded in the following table. All compositions contain 10% ethyl alcohol and the balance water.

CompositionNo 8 9 10 11 12 13 Percent G Performance at pH 7 Performance at pH 5 Either A,C,D,E,F, or G 1 Sudsing was too low to measure by this test method.

As can be seen from the preceding data, the amine oxides of this invention give outstanding results only with the sulfate detergent surfactants of this invention. Composition 8 demonstrates that mixtures of sulfate surfactants within the scope of this invention will give results substantially equivalent to those of a single sulfate surfactant such as either the sodium alkyl sulfate of Composition 9 or the ammonium salt of the sulfated condensa tion product of one mole of middle-cut coconut alcohol and three moles of ethylene oxide in Composition 12. In contrast to these three tests, Composition 10 demonstrates that a sulphonate surfactant (sodium alkyl sulphonate) does not give the same outstanding results. Similarly, Composition 13 demonstrates that the presence of an aromatic ring in a sulfate (ammonium tetrapropylene benzene ethylene oxide sulfate) impairs the sudsing performance somewhat. Composition ll demonstrates that when both the sulfonate and aromatic structures are present in a detergent surfactant molecule, sudsing performance is drastically impaired under acidic conditions.

aura-see A detergent composition was prepared containing 20% by weight of the composition of the sulfate detergent surfactant of Example I, 5% by Weight of the composition of the amine oxide of Example I, 12% by Weight of the composition of ethyl alcohol, 0.1% by weight of the composition of ammonium citrate, 0.3% by Weight of the composition of perfume, and the balance water. This composition was used under typical home washing conditions and was found to be an exceptional high-sudsing light duty liquid detergent.

A similar composition containing 0.2% by Weight of the composition of a 1% by Weight solution of yellow coloring was prepared, and this too proved to be an exceptional high-sudsing light duty liquid detergent in typical home-use tests under alkaline, neutral, and particularly acidic conditions.

When the sulfate detergent surfactant in the preceding example is the monoethanolamine, diethanolarnine, triethanolamine or potassium salts, substantially equivalent results are achieved.

Similarly when the ethyl alcohol solubilizing agent is replaced by methyl, isopropyl, or normal propyl alcohols, substantially equivalent results are achieved.

Also when ammonium and sodium xylene sulfonates and sodium and ammonium toluene sulfonates are added to the composition of the above example in amounts up to 5% by weight of the composition, substantially equivalent results are achieved.

What is claimed is:

1. An unbuilt, high-sudsing, ligh-duty liquid detergent composition having a pH of from about 6.5 to 9.0 and having special utility for washing under acidic conditions Where the pH of the Wash Water is less than about 6.5 and consisting essentially of (1) from about 20% to about by weight of the composition of a sulfate detergent having the following formula R-(C H O -SO --Me wherein R is a straigh chain alltyl group having from about 10 to about 14 carbon atoms with at least 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 monoethanolainine, diethanolamine, triethanolarnine, ammonium, sodium, and potassium cations; (2) a trialkyl amine oxide having one straight chain alkyl group having from about 10 to about 14 carbon atoms, with at least 50% of said alkyl groups having 12 carbon atoms, and two short chain alkyl groups having from one to about two carbon atoms, in an amount sufficient to give a Weight ratio of sulfate detergent to amine oxide of from 3/1 to 7/1; (3) at least about 5% but not more than about 40% by weight of the composition of a solubilizing agent selected from the group consisting of methyl, ethyl, n-propyl, and isopropyl alcohols, and mixtures thereof, said agent being sufficient to provide a pourable homogeneous composition; and (4) the balance water.

2. 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.

Roi-entrees Qited by the Examiner UNITED STATES PATENTS 2,060,568 11/36 Graenacher et al. 252-152 XR 2,169,976 8/39 Guenther et al. 252-152 XR 2,310,074 2/43 Gotte S54 2,607,740 8/52 Vitale et al 252-153 X 2,861,956 11/58 Fernandez 252153 2,999,068 9/61 Pilcher et al. 252-152 XR 3,001,945 9/61 Drew et a1 252-152 XR FOREIGN PATENTS 206,622 3/ 59 Australia.

JULIUS GREENWALD, Primary Exmniner.

Claims (1)

1. A UNBUILT, HIGH-SUDSING, LIGHT-DUTY LIQUID DETERGENT COMPOSITION HAVING A PH OF FROM ABOUT 6.5 TO 9.0 AND HAVING SPECIAL UTILITY FOR WASHING UNDER ACIDIC CONDITIONS WHERE THE PH OF THE WASH WATER IS LESS THAN ABOUT 6.5 AND CONSISTING ESSENTIALLY OF (1) FROM ABOUT 20% TO ABOUT 40% BY WEIGHT OF THE COMPSOTION OF A SULFATE DETERGENT HAVING THE FOLLOWING FORMULA