US 3192166 A
Description (OCR text may contain errors)
United States Patent 3,192,166 LIQUID DETERGENT COMPOSITION Norman R. Smith, Cincinnati, Ohio, assignor to The Procter & Gamble Company, Cincinnati, Ohio, a corporation of Ohio No Drawing. Filed Nov. 14, 1960, Ser. No. 68,652 '5 Claims. (Cl. 252-137) This invention relates to opaque built liquid detergents of themedium-duty and heavy-duty type. More particularly, it relates to such liquid detergents which contain a unique opacifying agent and have improved sudsing and detergent characteristics.
A built detergent is one which contains, in addition to at least one organic 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. In recent years, built liquid detergents have, to some extent, replaced built granular detergents for various reasons. These reasons include: complete freedom from dustiness, compact package and convenience in pouring and measuring. In addition, from the manufacturers standpoint, liquid detergents oifer relative simplicity in'manufacturing techniques.
The primary problem which has to be overcome in formulating built liquid detergents which are homogeneous in nature is that of incorporating sufiicient surface active agent and builder into the same solution. (By homogeneous as used herein is meant free from a precipitate of detergent actives.) In current practice anionic sulfated or sulfonated compounds are ordinarily used as surface active agents, and potassium pyrophosphate is used as the builder. Various surface active agents, hydrotr-opes 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 the manufacturer to include sodium silicate in the formulation as a corrosion inhibitor. However, with the addition of sodium silicate, special measures have to be taken to prevent the loss of homogeneity of the liquid formulation. For example, limitations on the pH of the formulation or the addition of agents designed to achieve compatibility among its constituents is usually required.
Compositions thus formulated are generally clear liquids of relatively low viscosity. As a manifestation of the compatibility of the ingredients, such physical In the following disclosure of the invention, percentages refer to weight percent of the total formula unless otherwise indicated. It will be appreciated that the alkali metal salts may be used interchangeably, since in an aqueous system it is for the most part immaterial how a particular ion is introduced, there being a substantially complete and continuous exchange of ions among the comborate decahydrate (borax, sodium borate, U.S.P. XIII),
sumer to exceed recommended product usage levels, a
practice which gives rise to uneconomical usage and decreased detergent elfectiveness due to excessive sudsing. In order to dispel this impression and alleviate this problem, various measures have been taken to modify ponents of the system.
In general, formulations such as the following comprise the invention: 1) from about 2% to about 15% of an alkali metal salt of a borate anion, the said salt having a solubility in water of not more than 5% at 25 C. and being sufficient to yield an opaque solution having a viscosity of at least about 350 centipoises at F.; (2) from about 3% to about 10% of an aliphatic tertiary amine oxide; (3) from about 3% to about 15% of a non-soap synthetic detergent of the sulfated or sulfonated type; (4) from about 3% to about 10% of a soluble hydrotrope; and (5) from about 10% to about 30% of a soluble pyrophosphate salt. The organic detergent actives, hydrotrope and phosphate are dissolved in an aqueous vehicle and the borate salts are added to the solution. 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.
The alkali metal borates which find utility in this invention have a solubility of 5% or less in water at 25 C. Borates of greater solubility do not yield compositions having the opaque, viscous character desired in the practice of this invention. Of the alkali metal borates which fall within the limitation defined above, sodium tetra- Na B O -10H O or Na O'2B O -10H O and potassium pentaborate, KB O -4H O or K O-5B O -8H O are especially efiicacious.
The borate salt must comprise from about 2% to about 15% by weight of the total composition. Less than 2% of this component will not yield the preferred degree of opacity and viscosity, i.e., the solution will be clear or translucent rather than opaque and will have a viscosity of less than 350 centipoises at 75 F. Amounts greater than 15% will adversely affect the stability and homogeneity of the solution. Preferably, this component should comprise from about 4% to about 10% by weight of the total composition.
Amine oxides, which are essential components of the detergent compositions of this invention, 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 ofthis 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 formulation of this invention is too low if R is greater than 16 carbon atoms. Preferably, R is a dodecyl radical or a mixture of dodecyl with decyl, tetradecyl and hexadecyl radicals, such that at least 50% of the radicals are dodecyl radicals. A convenient source of the preferred mixture of alkyl radicals designated R is the middle cut of coconut fatty alcohol which has the approximate chain length composition: 2%C10, 66%C12, 23%C14, and 970- 5.
R and R are each selected from the group consisting of methyl and ethyl radicals. Preferably, R and R are methyl radicals.
The amine oxide is used at from about 3% to about of the total formula. Less than about 3% amine oxide adversely affects the performance of the formulations and more than about 10% amine oxide interferes with achieving homogeneity between builder and .detergent when present in the liquid formulation in, sufficient amounts.
Soluble pyrophosphate salts are suitable builders in the liquid detergent compositions of 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 non-soap 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 various other sequestering agents, are corrosive towards aluminum. If the detergent solution is to contact this metal repeatedly or for prolonged periods of time, especially at elevated temperatures, acorrosion inhibitor should be desirably included.
.Soluble silicates are highly'effective inhibitors and can be added to the formulas of this invent on at levels of from about 3.5% to about 6%. Potassium, or preferably sodium silicates having a Weight ratio of SiO /M O 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% of silicate solids, although usable in the present compositions, does not provide protection against corrosion in heavy duty use conditions, and more than about 6% of silicate solids has an adverse effect upon the desired homogeneity of the liquid composition.
Suitable hydrotropes to increase the compatibility of the ingredients in the formulations of this invention are the aryl sulfonates. More specifically, they are soluble salts of the hydrotrope anions. Preferred salts of hydro 'trope anions are benzene sulfonate, xylene sulfonate and toluene sulfonate. They are used as the soluble salts such as:' ethanolammonium, diethanolammonium, and triethanol-ammonium 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 'offrom about 3% to about 10% and sufficient to achieve homogeneity in the detergent solution. Levels of from about 4% to about 6% are preferred. The upper limit of about 10% is dictated by the dilution effect on the product of an ingredient which-is substantially inert so far as sudsing and detergency are concerned. The lower limit is the amountrequired toachieve a homogeneous solution. Itwill be appreciated that it is necessary that the formulations of this invention should be liquid at somewhat higher and somewhat lower temperatures than usual room temperature. The amount of hydrotrope salt'used is preferably the minimum amount which will prevent precipitation of the detergent actives throughout the temperature ranges to which the product is likely to be subjected.
It has been found that in order to achieve the objects of this invention, a non-soap anionic synthetic detergent must also be present in the detergent compositions contemplated herein. -=Fr-om about 3% to about 15% of anionic detergent is employed. Preferred anionic detergents which have been found beneficial for purposes of this invention are: alkyl benzene sulfonate, alkyl ethylene oxide ether sulfate wherein there are from 1 to 5 ethylene oxide residues per alkyl group, and alkyl sulfate. The anions of these anionic deter-gents may be represented,
R(OC H SO 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 readily soluble and available from a synthetic source such as a mixture containing tri-, tetra-, and pentapolypropylene polymers and averaging about 12 carbon atoms obtained from petroleum hydrocarbons or from natural sources, such as the mixture of fatty alcohols derived from coconut oil.' These detergents are,'of course, used in the form of their water soluble salts; specifically, they are used as sodium, potassium, ethanolammonium, diethanolammonium, and triethanolammonium salts. The sodium and tri-ethanolammonium salts are preferred.
Although alkyl benzene sulfonate and alkyl sulfate are especially preferred, other non-soap anionic synthetic detergents, containing alkyl radicals as specified above, can be usefully employed in the compositions of this invention if they have the following characteristics: their salts, as specified above, are soluble to the extent of at least 3% in an aqueous solution consisting of a mixture of 3% dimethyld-odecylamine oxide, 3% potassium toluene sulfonate, 10% potassium pyrophosphate, and 2% potassium borate; 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.
Because of the, presence of the amine oxide, the compositions of this invention suds so well in the laundry and dishpan that no suds builder is required. Among the anionics, the alkyl sulfate and alkyl benzene sulfonate make a particular contribution to sudsing in the compositions of this invention. Alkyl benzene sulfonate as hereinbefore defined is particularly favored for this purpose because in most circumstances it reduces the cost of the formula.
The anionic detergent can tend to improve the mildness of the formulations, alkyl benzene sulfonate being partic ularly noteworthy in this respect.
Anionic detergents also permit the incorporation of higher levels of active ingredients in a given amount of solvent (water) while still maintaining homogeneity of the liquid composition, i.e., the compositioncan be made more concentrated.
Preferred compositions of this invention will include two anionic detergents, for example, C -alkyl benzene sulfonate and coconut alkyl sulfate in approximately equal quantities. 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% by weight of the total composition.
The inorganic builder content is preferably raised as the total synthetic detergent content is loweredg'so that the sum of builder and detergent iskept within the range of about 25% to about 40% by weight of the total composition. It has been found that if these limitations are obborate" selected from the group consisting of sodium tetraborate decahydrate and potassium pentaborate;
(b) from about 3% to about of an aliphatic tertiary amine oxide having the general formula R R R N O Where R 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 50% of said amine oxide having an R alkyl radical containing 12 carbon atoms;
(c) from about 3% to about of non-soap deter gent selected from the water-soluble salts of the group of detergent anions consisting of RSO R(OC H S=O. where x isan integer from 1 to 5,
R being an alkyl radical containing about 9 to about 6 carbon atoms, and mixtures thereof;
(d) from about 3% to about 10% of a salt of a hydrotrope anion of the groupconsisting of toluene sulfonate, benzene sulfonate, and xylene sulfonate;
(e) from about 3.5% to about 6% silicate solids having an SiO /M O ratio of from about 16:1 to about 2.621 where M is selected from the group consisting of sodium and potassium;
(if) from about 10% to about 30% of a salt of pyrophosphate anion; and the balance substantially (a) 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 roup consisting of potassium, sodium, e-thanolammonium, diethanolainmonium, and triethanolammonium, the mole ratio of the total of potassium and alkanolarnmonium cations to sodium cations being greater than about 3:1.
2. An opaque viscous liquid detergent composition consisting essentially of:
(a) from about 4% to about 10% of an alkali metal borate selected from the group consisting of sodium tetraborate decahydrate, and potassium pen-taborate.
(b) 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 said amine oxide having an R alkyl radical containing 12 carbon atoms;
(c) from about 3% to about 15% of a sodium salt of a non-soap detergent anion selected from the group consisting of R80 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;
(d) from about 3% to about 10% of potassium toluene. sulfonate;
(e) from about 10% to about 30% of potassium pyrophosphate; and the balance substantially (f) Water.
3. An opaque viscous liquid detergent composition consisting essentially of:
(a) from about 4% to about 10% of an alkali metal borate selected from the group consisting of sodium tetraborate decahydrate and potassium pentaborate.
(b) from about 3% to about 10% of an aliphatic tertiary amine :oxide having the general formula- R being an alkyl radical containingabout 9 to about 16 carbon atoms, and mixtures thereof;
(d) from about 3 to about 10% of potassium toluene sulfonate;
(e) from about 3.5% to about 6% silicate solids of the composition SiO uNa O, their weight ratio being from about 1.6:1 to about 2.6:1;
(f) from about 10% to about 30% of potassium pyrophosphate; and the balance substantially (g) Water.
4. An opaque viscous liquid detergent composition consisting essentially of: (a) from about 4% to about 10% of sodium tetraborate decahydrate; (b) from about 3% to about 10% or" coconut dimethyl amine oxide; (c) from about 3% to about 15% of a member selected from the group consisting of sodium dodecyl benzene sulfonate, sodium coconut sulfate and mixtures thereof; (d) from about 4% to about 6% of potassium toluene sulfonate; (e) from about 10% to about 30% of potassium pyrophospate; and the balance substantially; (f) water.
5. An opaque viscous liquid detergent composition consisting essentially of:
(a) 6.0% of dimethyldodecylamine oxide;
(b) 6.0% of the triethanolamine saltof alkyl benzene sulfonate wherein the alkyl group is a mixture of tri-, tetra-, and pentapropylene and has an average carbon content of about 12;
(c) 25.0% of potassium pyrophosphate;
(d) 8.5% of potassium toluene sulfonate;
(e) 5.0% of sodium tetraborate decahydrate;
(f) 5.0% sodium silicate solids having an SiO /Na O ratio of 1.6; and
(g) the balance water, the molar ratio of potassium and triethanolammonium to sodium being approximately 5.5.
References Cited by the Examiner UNITED STATES PATENTS 1,753,395 4/30 Wilkes 252-137 2,169,976 8/39 Guenther et ah 260404.5 2,581,677 1/52 Machlis et al. 252137 2,999,068 9/61 -Pilcher et al. 252-137 3,085,982 4/63 Steer et al. 252-137 FOREIGN PATENTS 800,706 9/58 Great Britain.
OTHER REFERENCES The American Perfumer and Essential Oil Review, by Harris, vol. 48, No. 11, November 1946, pages 54-56.
JULIUS GREENWALD, Primary Examiner.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,192,166 June 29, 1965 Norman R, Smith It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.
Column 6, Example IV, in the table, first column, line 8 thereof, for "pentapropulene" read pentapropylene column 7, line 19, for "6 carbon" read 16 carbon line 24,
for "16:1" read 1.6:1 "I
Signed and sealed this 28th day of December 1965.
ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents