US3085982A

US3085982A - Liquid detergent composition

Info

Publication number: US3085982A
Application number: US808022A
Authority: US
Inventors: David C Steer; Norman R Smith
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1959-04-22
Filing date: 1959-04-22
Publication date: 1963-04-16
Anticipated expiration: 1980-04-16
Also published as: DE1185756B; GB951930A; BE622462A; NL250715A; GB1091517A

Description

cohol.

added to an already complicated formula, these suds builders may require, in certain formulations, a partic- United States Patent Ofice 3,085,982 Patented Apr. 16, 1963 3,085,982 LIQUID DETERGENT COMPOSITION David C. Steer and Norman R. Smith, Cincinnati, Ohio,

assiguors to The Procter & Gamble Company, Cincinnati, Ohio, a corporation of Ohio No Drawing. Filed Apr. 22, 1959, Ser. No. 808,022 8 Claims. (Cl. 252-437) This invention relates to liquid detergents of mediumduty and heavy-duty, sudsing type. More particularly, it relates to improved liquid detergents which contain a tertiary amine oxide surface active agent.

In recent years built liquid detergents have been gaining favor for washing soiled clothing, for washing dishes and for other purposes requiring an effective detergent. A built detergent is one which contains, in addition to the surface active agent, a soluble salt capable of sequestering calcium and magnesium ions of hard water and also capable of increasing the level of detergent effectiveness of the surface active agent. Built liquid detergents have, to some extent, replaced granular built detergents for various reasons. These reasons include: complete freedom from dustiness, compact package, convenience in pouring and measuring, and simplification of manufacture.

The problems which have to be overcome in formulating built detergents in clear homogeneous liquid form are mainly the problems of incorporating sufficient surface active agent and builder into the same solution. In current practice an anionic sulfated or sulfonated compound is ordinarily used as surface active agent, and potassium pyrophosphate is used as builder. Various surface active agents, hydrotropes and solvents are employed to increase their compatibility. The fact that the builder may corrode non-ferrous metals such as aluminum, may, depending on the use for which the product is intended, lead to the inclusion of sodium silicate as a corrosion inhibitor. Its presence requires that special provisions be made to keep the ingredients compatible. Limitations on the pH of the formulation or the presence of agents designed to achieve compatibility is usually required.

In U.S. Patent 2,859,182 a combination of alkali metal aryl sulfonate and at least one alkylolamide is disclosed for making certain detergent compositions homogeneous. In these compositions the pH must be adjusted to about 11.4 or above to keep silicate in solution.

Different agents for solving the problem of making detergent, builder and silicate compatible, which are disclosed in US. Patents 2,877,185 and 2,877,186, are: a solubilizing agent, for example triamylphosphate or potassium benzene sulfonate; and an assistant solubilizer," for example ethyl alcohol or diethyleneglycol monobutyl ether; and a particular detergent, alkyl glyceryl ether sulfonate. The alkyl glyceryl ether sulfonate and the solubilizing agent are used together, and the assistant solubilizer is preferably included.

Liquid detergents generally contain one or more agents, called suds builders, to increase their sudsing. Typical suds builders are coconut ethanolamide and lauryl al- In addition to being one more ingredient to be ular perfume to cover their odor. Amide-type suds builders, unless purified, are often undesirably highly colored for use in liquid products. They are not considered to serve the cleaning function of a detergent.

An object of this invention is to provide a homogeneous built liquid detergent of improved sudsing characteristics and good detergent effectiveness.

A further object of this invention is to eliminate suds builders from a high sudsing liquid detergent formulation.

An additional object of this invention is to eliminate the need for solvent and/ or special surface active agents (alkylolamide or alkylglyceryl ether sulfonate) in a homogeneous built liquid detergent; the object of an aspect of the invention is to do so when silicate is present.

These and other objects are accomplished by a detergent formulation containing: (I) from about 3% to about 10% of an aliphatic tertiary amine oxide; (2) from about 3% to about 15% of a non-soap synthetic detergent of the sulfated or sulfonated type; (.3) from about 3% to about 10% of a soluble hydrotrope; and (4) from about 10% to about 30% of a soluble pyrophosphate salt. These ingredients are dissolved in an aqueous vehicle. When the use of the formulation makes a corrosion inhibitor desirable, from about 3.5% to about 6% of alkali metal silicate solids are dissolved in the same solution.

In the following more complete disclosure of the invention, percentages refer to weight percent of the total formula unless otherwise indicated. It will be appreciated that in an aqueous system it is for the most part immaterial by which ionic salts a particular ion is introduced; for in the aqueous product there will be substantially complete and continuous exchange of ions.

Amine oxides are compounds of the general formula R R R N- O. The arrow is a conventional representation of a semipolar bond. They are generally prepared by the direct oxidation of the appropriate tertiary amine. When R is a much longer chain than R and R amine oxides have surface activity. For the purpose of this invention R is an alkyl radical of from about 10 to about 16 carbon atoms. Desirable surface active properties are lost if R is substantially less than 10 carbon atoms, and solubility in the present formulation is too low if R is greater than 16 carbon atoms. R and R are each selected from the group consisting of methyl and ethyl radicals. Preferably R is a dodecyl radical or a mixture of dodecyl with de-cyl, tetradecyl and hexadecyl radicals, such that at least 50% of the radicals are dodecyl radicals. A convenient source of a preferred mixture is the middle cut of coconut fatty alcohol which has the approximate chain length composition: 2%C 66%C 23%C, and 9%C R and R are preferably methyl radicals. The amine oxide is used at from about 3% to about 10% of the total formula. Too little amine oxide adversely affects the performance of the formulations and too much amine oxide interferes with achieving builder and detergent in sufficient amount in a homogeneous liquid.

Soluble pyrophosphate salts are suitable builders in this invention. They complex the calcium and magnesium ions of hard water; and, when the calcium ions of hard Water are present in excess, have an additional water softening effect by precipitating calcium pyrophosphate. They also serve to increase the level of detergency obtainable with synthetic surface active agents. Potassium, sodium, ethanolammonium, diethanolammonium, and triethanolammonium are suitable salts of the pyrophosphate anion in the practice of this invention; potassium pyrophosphate is especially preferred. The soluble salt of pyrophosphate is employed at a level of from about 10% to about 30%.

The pyrophosphate salts, like other sequestering agents, are corrosive towards aluminum. If the detergent solution is to contact this metal for prolonged periods of time, especially at elevated temperatures, a corrosion inhibitor should be desirably included. In a product designed for hand laundry of fine fabrics, it is unnecessary. Soluble silicates are highly effective inhibitors and can be added to the formulas of this invention without difficulty at levels of from about 3.5% to about 6%. Potassium, or preferably sodium silicates haviug a weight ratio of Slog/M20 of from about 1.0 to about 2. 6 and preferably from about 1.6 to about 2.6 can be used. M in this ratio refers to sodium or potassium. Less than about 3.5% sodium silicate solids, although useable in the present compositions, does not provide protection against corrosion at typical use conditions, and more than about 6% sodium silicate solids is difficult to incorporate into a homogeneous liquid.

Suitable hydrotropes to increase the compatibility of the ingredients of the formulations of this invention are the aryl sulfonates disclosed in the hercinbefore cited patents. More specifically they are soluble salts of the hydrotrope anions. Preferred hydrotrope anions are benzene sulfonate, xylene sulfonate and toluene sulfonate. They are used as the soluble salts such as: ethanolammonium, diethanolammonium, and triethanolammonium and especially as the alkali metal, potassium, or sodium, salts. Sodium or potassium toluene sulfonate is especially preferred. The hydrotrope salt is added at levels of from about 3% to about 10%. Levels of from about 4% to about 6% are preferred. The upper limit of about 10% is set by increasing dilution of the product by an ingredient substantially inert so far as sudsing and detergency are concerned. The lower limit is the amount required to achieve a homogeneous solution. It will be appreciated that it is necessary that the formulations of this invention should be liquid at somewhat higher and at somewhat lower tem peratures than usual room temperature. The amount of hydrotrope salt used is preferably the minimum amount which will hold the ingredients in solution at the temperature to which it is desired that the formula can be cooled without phase separation.

Amine oxide is an effective detergent; however, in order to achieve the objects of this invention, a supplemental non-soap anionic synthetic detergent is added. From about 3% to about 15% anionic detergent is employed. Preferred anionic detergents which can be included are: alkyl benzene sulfonate, alkyl ethylene oxide ether sulfate wherein there are from 1 to ethylene oxide residues per alkyl and the mixtures formed when 1 to 5 ethylene oxides are reacted with one mole of alcohol, and alkyl sulfate. These may be represented, respectively, as:

where x is an integer from 1 to 5, and R80 In these compounds the alkyl chain (R) will contain from about 9 to about 16 carbon atoms and preferably about 12 carbon atoms. Mixtures of alkyl radicals of different chain lengths are preferably used since they are soluble and readily available from synthetic or natural sources, e.g., coconut alcohol and a mixture containing tri-, tetra-, and pentapolypropylene polymers and averaging about 12 carbon atoms. These detergents are used as soluble salts; specifically, they are used as sodium, potassium, ethanolammonium, diethanolammonium and triethanolammonium salts. Sodium and triethanolamine salts are preferred. Other non-soap anionic synthetic detergents, with alkyl radicals as specified above, can be usefully employed if they have the following characteristics: their salts, as specified above, are soluble to the extent of at least 3% in an aqueous solution of 3% dimethyldodecylamine oxide, 3% potassium toluene sulfonate and potassium pyrophosphate; and they are stable against hydrolysis in alkaline solution. An example is the potassium salt of the sulfated condensation product of four moles of ethylene oxide with a mole of nonyl phenol.

The formulas of this invention, containing amine oxide, suds so well in the laundry and dishpan that no suds builder is required. Among the anionics, the alkyl sulfate makes a particular contribution to sudsing in the formulas of this invention. Alkyl benzene sulfonate is particularly favored for this purpose because in most circumstances it reduces the cost of the formula. A supplemental anionic detergent can tend to improve the mildness of the formulations, alkyl benzene sulfonate being particularly noteworthy in this respect. The supplemental anionic detergents also permit the achieving of higher levels of active ingredients in a homogeneous liquid. Alkyl benzene sulfonate and alkyl sulfate are therefore especially preferred anionic detergents. Preferred formulas of this invention include those in which two anionic detergents are used in combination with the amine oxide. For example, C alkyl benzene sulfonate, coconut alkyl sulfate and dimethyldodecylarnine oxide in approximately equal quantities in a detergent combination which gives superior sudsing. good mildness to the skin and relatively low cost and is especially preferred in the practice of this invention. Slight variations from equal quantities of the amine oxide and the anionic detergents permits fine adjustment of the properties of the formulas. If more of one detergent is used, preferably less of another is used. To maintain the homogeneous character of the product, the sum of anionic detergent and amine oxide is preferably kept in the range of from about 10% to about 25%.

The inorganic builder content is preferably raised as the total synthetic detergent content is lowered; so that the sum of builder and detergent is kept from about 25% to about 40%. In this range of composition the product has particularly good performance and homogeneous character. As a rough generalization, when the total detcrgent is greater than the builder the product is of medium-duty type and can be recommended for hand laundering of fine fabrics and dishwashing. When the detergent level is lowcr or equal to the builder, the product is of heavy-duty type especially adapted for laundry and general purpose use. Silicate is particularly desirable in the heavy-duty product.

In a finished detergent formulation there will preferably be added in minor amounts materials which make the product more effective or more attractive. The following are mentioned by way of example. A soluble sodium carboxymethylcellulose may be added in amounts up to about 2% to inhibit soil redeposition. A tarnish inhibitor such as benzotriazole or ethylenethiourea may be added in amounts up to about Fluorescers, perfume, and color, while not essential in the compositions of the invention, may be added in amounts less than about 1%.

All the constituents of these liquid detergent formulations are dissolved in water with the possible exception of certain of the minor nonessential ingredients which are at least finely and homogeneously dispersed to give the effect of a onephase composition. A maximum water level of about 70% is set by the need to get enough active ingredient in the solution to hold the volume required per usage to an acceptable level. The minimum water level of about 45% is set by the requirement of having sufiicient water to dissolve the ingredients.

The mole ratio of potassium (and any alkanolammonium ions) to sodium is maintained above about 3:1 to maintain the one-phase nature of the product and preferably is maintained above about 3.511.

Example I The following compositions were prepared and examined. All were clear homogeneous pourable liquids at room temperature. Formulas B and C were cooled to lower temperatures and remained clear at 50 F.

Dimethyldodccyl amino oxide percent 4 5 7 5 8 6 Sodium polypropylene benzene sulfonate (a mixture. of tri-, tetrm, and peutapropylenit averaging about C12} percent" 4 ti 3 5 Sodium coconut sulfate. .do 4 2 3 4 4 8 Potassiutntoluencsulfunate do. 6 7 G t, 6 (I lotassiumpyrophosphate lo. 15 18 18 ltt 18 Sodium silicate solids S5102:

' r at," as as} as as as is ,do 0.1) (1.15 Water do t l l?) (I K/Nu,approx 1nole rutio lo 4.1 4.2 l o i 5.0 d J 1 Coconut refers to the alkyls of lllltltllt? cut coconut ult-ohul containing about 292-010. [itilk-On, filmy-Cu ul1tl9;T;,.-C s.

2 Balance.

An additional composition, G, was prepared as a duplicate of F except the 8% sodium coconut sulfate was replaced by 6% potassium salt of a sulfated condensation product of one mole coconut 1 alcohol with 3 moles of 1 Coconut refers to the alkyls of middle out coconut alcohol containing about 2%Cio, 66%Ci2, 23%'C14. and 9%Cld. ethylene oxide. The K/ Na mole ratio in this product was about 7.4.

Products A, C, D, and F proved to be superior in maintaining suds during the washing of soiled dishes to com- 10 mercially available built liquid detergents tested under the same conditions. Products B and G proved to be good dishwashing products, being about equal to available built liquid products.

Products B and C were also employed in washing soiled clothes in a typical domestic washing machine. The suds in the first load was higher than for commercial built liquid detergents tested under the same conditions.

The sodium silicate can be omitted from these formulas without substantially affecting appearance or performance except for their corrosiveness to non-ferrous metals. Dodecyl radicals and coconut radicals are substantially equivalent, that is one can be substituted for the other in the ingredients of this example with no substantial change in appearance or performance of the product. Potassium benzene sulfonate or potassium xylene sulfonate can be used to replace potassium toluene sulfonate without losing the homogeneous nature of the product or adversely affecting its performance.

Example I] The following composition was prepared. It was a clear homogeneous pourable liquid at room temperature. It remained clear at 30 F.

Percent Dimethyldodecylamine oxide 6 Triethanolamine salt of polypropylene benzene sulfonate (a mixture of tri-, tetra-, and pentapropylene averaging about C 6 Potassium pyrophosphate 25 Potassium toluene sulfonate 8.5 Sodium silicate solids, Si0 to Na O is 1.6 5 Water Balance K-l-triethanolammonium/Na, approx. mole ratio 5.5

The suds during washing soiled dishes obtained from this product were more stable than suds obtained from commercially available built liquid detergents. This product showed good sudsing and cleaning characteristics in washing soiled clothing.

Example 111 The following compositions were prepared. They were clear homogeneous pourable liquids at room temperature. After freezing at 40 F. they again became clear and homogeneous on being warmed to room temperature.

I A l B Dirnethyleoconut I amine oxide 5.0 6.0 Sodium coconut 1 ethylene oxide ether suit-ate (average of 3 ethylene oxide residues per molecule) 8. 5 10.0 Sodium coconut I alkyl sulfate 2. 5 Sodium polypropylene benzene sullonate (a mixture oitri-, tetra, and pentapropyleue averaging about C12) 4.0 4.0 Potassium pyrophosphate 12 12 Potassium toluene suli'onate 5 5 Color 0.0013 0 0013 Bonzotriazole 0. 02 (I. 02 Water Balance Balance K/Na, approx. mole re 4. 2 4. S

i (oconut refers to the alkyls of middle out coconut alcohol containing about 2G1t, 6651-0 2, 237 -014, and9%C for the purposes for which medium-built liquid products are intended.

In these compositions, methylethylcoconutamine oxide or diethylcoconutamine oxide can be substituted for dimethylcoconutamine oxide without substantially adversely affecting the physical characteristics or performance of the compositions.

What is claimed is:

1. A substantially clear, high-sudsing, concentrated liquid detergent composition consisting essentially of:

(a) from about 3% to about 10% of an aliphatic tertiary amine oxide having the general formula R R R N- 0, where R; is an alkyl radical containing from about 10 to about 16 carbon atoms and R and R are each selected from the group consisting of methyl and ethyl radicals, at least about 50% of said amine oxide having R containing 12 carbon atoms;

(b) from about 3% to about 15% of a non-soap detergent selected from the salts of the group of detergent anions consisting of R R(OC H SO where x is an integer from 1 to 5 R being an alkyl radical containing about 9 to about 16 carbon atoms, and mixtures thereof;

(0) from about 3% to about 10% of a salt of a hydrotrope anion selected from the group consisting of toluene sulfonate, benzene sulfonate, and xylene sulfonate;

(d) from about 10% to about 30% of a salt of a pyrophosphate anion; and the balance substantially (e) water; the cations of the salts of the group of detergent anions, of the salts of the hydrotrope anions, and of the salts of the said pyrophosphate anion being selected from the group consisting of potassium, sodium, ethanolammonium, diethanolammonium, and triethanolammonium, and the mole ratio of the total of potassium and of alkanolarnmonium cations to sodium cations being greater than about 3:1, said composition being substantially free from amide suds-builders.

2. The liquid detergent composition of claim 1 wherein in the tertiary amine oxide R and R are each methyl radicals.

3. A substantially clear high sudsing concentrated liquid detergent composition consisting essentially of:

(a) from about 3% to about 10% of an aliphatic tertiary amine oxide having the general formula R R R N- O where R is an alkyl radical containing from about 10 to about 16 carbon atoms and R and R are each selected from the group consisting of methyl and ethyl radicals, at least about 50% of said amine oxide having R containing 12 carbon atoms;

(b) from about 3% to about 15% of a non-soap detergent selected from the salts of the group of detergent anions consisting of R80 R(OC H SO where x is an integer from I to 5 R being an alkyl radical containing about 9 to about 16 carbon atoms, and mixtures thereof;

(d) from about 3.5% to about 6% of silicate solids of the composition SlOgIMgO their weight ratio being from about 1.6:1 to about 2.6:] and wherein the M of M 0 is selected from the group consisting of sodium and potassium;

(e) from about 10% to about 30% of a salt of a pyrophosphate anion; and the balance substantially (f) water; the cations of the salts of the said detergent anions, of the salts of the said hydrotrope anions, and of the salts of the said pyrophosphate anion being selected from the group consisting of potassium, sodium, ethanolammonium, and triethanolammonium, the mole ratio of the total of potassium and alkanolammonium cations to sodium cations being greater than about 3:1, said composition being substantially free from amide suds-builders.

4. The liquid detergent composition of claim 3 wherein the amine oxide R and R are each methyl radicals.

5. The liquid detergent of claim 3 wherein the detergent anion is R being an alkyl radical containing from about 9 to about 16 carbon atoms.

6. The liquid detergent composition of claim 3 wherein the detergent anion is a mixture of R -s Os-and R s or R being an alkyl radical containing from about 9 to about 16 carbon atoms.

7. The liquid detergent composition of claim 3 wherein the hydrotrope anion is toluene sulfonate.

8. A substantially clear high-sudsing liquid detergent composition consisting essentially of:

(a) from about 3% to about 10% of an aliphatic tertiary amine oxide having the general formula R R R N O where R is an alkyl radical containing from about 10 to about 16 carbon atoms and R and R are each methyl radicals, at least about 50% of 8 said amine oxide having R containing 12 carbon atoms;

(b) from about 3% to about 15% of a sodium salt of a non-soap detergent anion selected from the group consisting of R R(OC H SO where x is an integer from 1 to 5 References Cited in the file of this patent UNITED STATES PATENTS 2,060,568 Graenacher et al Nov. 10, 1936 2,169,976 Guenther et al Aug. 15, 1939 2,581,677 Machlis et al Jan. 8, 1952 2,877,186 Krumrei Mar. 10, 1959 FOREIGN PATENTS 437,566 Great Britain Oct. 31, 1935 OTHER REFERENCES The Chemistry of Fatty Amines, 1948, pub. by Armour and Co., page 13.

Claims

1. A SUBSTANTIALLY CLEAR, HIGH-SUDSING, CONCENTRATED LIQUID DETERGENT COMPOSITION CONSISTING ESSENTIALLY OF: (A) FROM ABOUT 3% TO ABOUT 10% OF AN ALIPHATIC TERTIARY AMINE OXIDE HAVING THE GENERAL FORMULA R1R2R3N$O, WHERE R1 IS AN ALKYL RADICAL CONTAINING FROM ABOUT 10 TO ABOUT 16 CARBON ATOMS AND R2 AND R3 ARE EACH SELECTED FROM THE GROUP CONSISTING OF METHYL AND ETHYL RADICALS, AT LEAST ABOUT 50% OF SAID AMINE OXIDE HAVING R1 CONTAINING 12 CARBON ATOMS; (B) FROM ABOUT 3% TO ABOUT 15% OF A NON-SOAP DETERGENT SELECTED FROM THE SALTS OF THE GROUP OF DETERGENT ANIONS CONSISTING OF RSO4-, R(OC2H4)XSO4-, WHERE X IS AN INTEGER FROM 1 TO 5