HOMOGENEOUS ENZYME-CONTAINING LIQUID DETERGENT COMPOSITIONS CONTAINING SATURATED FATTY ACIDS

Abstract: Homogeneous aqueous enzyme-containing liquid detergent compositions containing substantial levels of satu­ rated fatty acids, minute amounts of enzyme-accessible cal­ cium, and additive levels of selected short chain carboxylic acids are disclosed. These compositions exhibit a broad range of stability benefits with respect to the activity of the indi­ vidual ingredients as well as in respect to homegeneity.

Description: HOMOGENEOUS, ENZYNE-CONTAINING LIQUID DETERGENT COMPOSITIONS CONTAINING SATURATED FATTY ACIDS Flavio TOLFO and Christian BARRAT Technical Field This invention relates to homogeneous enzyme-cont2iring liquid detergent compositions containing substanti21 levels of saturated fatty acids. These compositions provide a series cf remcrkaLle stability benefits in respect to both functionality optimization of the individual ingredients and physica stability of the composition. ore particularly, the compositions of this invention unexpectedly provide the cumulative benefits inherent to the presence of the detergent enzyme and to the substantial level of the saturated fatty acid. There was a standing prejudice against the effective use of the like compositions, chiefly because of the contradictory behaviour of calcium in respect to saturated fatty acids and detergent enzymes. It is well-known that enzyme-containing liquid detergent compositions require the presence of certain minimum levels of calcium as a primary stabilizing agent. This is especially applicable for proteolytic and amylolytic enzymes. The liquid enzymatic detergent compositions of the prior art containing substantial levels of fatty acids and/or scaps are deficient with respect to important product characteristics. For example, the minimum level of calcium needed te provide acceptable enzymatic stability induces precipitation (in the liquid composition) in presence of substantial levels of saturated fatty acids and/or soaps. The like shortcomings can be overcome with the aid of known formulation changes inclusive of lowering the calcium level or using substantial levels of soluble calcium sequestrants. Both approaches can not be used in the context of this technology. The elimination or the substantial reduction of the calcium yields enzyme deactivation and instability upon aging. while the incorporation of strong sequestrants effectively cures the product instability, concurrently, it yields a substantial lowering of the enzymatic activity. These formulation constraints were such that it was not practically possible to simultaneously achieve product homogeneity, and effective enzyme stability in aqueous saturated fatty acid containing liquid detergents. It was no found that the prior art shortcomings can be circumvented with the aid of a narrowly defined ternary combiration, namely a saturated fatty acid sub-minimum levels of enzyme-accessible calcium and a specific short-chain carboxylic acid to thus formulate substantially builder-free homogeneous erzym,e-contair!ing liquid detergents. Description of the Art The formulation of enzymatic aqueous detergent compcsitions containing substantial levels of saturated fatty acids/ soaps is very difficult because of processing limitations and also because of the contradictory conditions under which saturated fatty acids/soaps and enzymes function in relation te calcium. While numerous attempts have been undertaken to formulate liquid detergent compositions allowing the simultaneous uce of saturated fatty acids and/or soaps in combina- tion with enzymes, success had not attended these efforts and no commercially-viable technology had been made available. U.S. Patent 3,676,374, Zaki et al., discloses enzymatic detergent compositions on basis of a mixed sulfonate/nonionic/ sulfate surfactant system and a proteolytic enzyme. Earth alkali-metal salts inclusive of calcium chloride, calcium acetate, magnesium chloride and magnesium acetate are recor..- mended for stabilizing the enzymatic activity. Concentrated enzyme containing alkaline liquid detergents are also known from French Patent 2,369,338. The active system of the '338 composition is comprised of a soap, a major amount of a nonionic ethoyylate and an anionic detergent. Comparable disclosures are known from French Patent 2,389,672, namely alkaline liquid detergents containing 2 major amount of a SC2 and relatively low level of other organic surfactants and alkaline buffering agent. Liquid detergent compositions containing a combination of nonionic ethoxylates, soaps, amylolytic and/or proteolytic enzymes and alkoxylated alkyl amines are also known from Belgian Patent 857,144. Thus while the individual ingredients cf the claimed invention are conventional in liquid detergent technology there wes a standing prejudice against using them concurrently; it was also not known that their combined use would provide significant benefits. The present invention relates to novel enzymatic liquid detergent compositions containing substantial amounts of saturated fatty acids, a short chain carboxylic acid, and having a neutral pH. Disclosure of the Invention The homogeneous aqueous detergent compositions of this invention comprise: (a) from about 20% to about 50% by weight of an organic synthetic surface-active agent; (b) from about 57 to about 15% by weight of a saturated fatty acid having 10 to 16 carbon atoms in the alkyl chain; (c) from 0.025S to about 1% by weight of ar enzyme; (d) from 0.1% to about 3% by weight of a carboxylic acid having from 1 to 3 carbon atoms; and (e) less than 2-millimoles of enzyme-accessible calcium per kilo cf the detergent composition, the pH of the composition reassured as is at 20 C, being from ahout 6.5 to 8.5. In the preferred embodiments of this invention, the saturated fatty acids have from 12 to 14 carbon atoms in the alkyl chain, the detergent enzymes are represented bg proteases o mixtures of prcteases and amylases, the short chain carboxylic acid is represented by formic acid, the enzyme-accessible calcium is present in an amount of from about 0.5 to l.5 millimoles per kilo of the detergent composition, and the pY of the composition, as is, is in the range from about 7 to about 7.5. The compositions of this invention are substantially builder free. While the fatty acids and/or soaps are not considered as detergent builders/ sequestrants in the context of this invention, the claimed compositions do not contain ore than minor amounts cf seouestrants. Detailed Description of the Invention Organic synthetic surface-active agents. The organic synthetic surface-active agents can be selected from nonionic, anionic, cationic, witterionic, amphoteric, ano semi-polar nonionic surfactants and mixtures thereof. While these surfactant components can be used over a wide concentration range, they are ncrmally used in levels ranging from about 20; to about SQ,v. Nonionic curfact2nts. The nonionic surfactants are conventionally produced by condensing ethylene oxide with â hydrocarbon having a reactive hydrogen atom, e.g., a hydroxyl, carboxyl, amino, or amido group, in the presence of an acicic cr basic catalyst. Nonionic surfactants have the general formula RA(CH2CH2O)nH wherein R represents the hydrophobic moiety, A. represents the group carrying the reactive hydrogen atom and n represents the average number Of ethylene oxide moieties. R typically contains from about 8 to 22 carbon atoms, but can also be formed by the condensation of propylene oxide with a lower molecular weight compound. n usually varies from about 2 to about 24. The hydrophobic moiety of the nonionic compound is preferably a primary or secondary, straight or branched, aliphatic alcohol having from about 8 to about 24, preferably from about 12 to about 20 carbon atoms. A more complete disclosure of suitable nonionic surfactants can be found in U.S. Patent 4,111,855 disclosed hereinbefore and incorporated herein by reference. fixtures of nonionic surfactants can be desirable. Anionic Surfactants. Synthetic anionic surfactants can be represented by the general formula R1So3E wherein R1 represents 2 hydrocarbon group selected from the group consisting of straight or branched alkyl radicals containing from about @ to about 24 carbon atoms and alkyl phenyl radicals containing from about 9 to about 15 carbon atoms in the alkyl group. N is a salt forming cation which typically is selected from the group consisting of sodium, potassium, ammonium monoalkanolamm@nium, dialkanolammonium, trialkanolammonium and mixtures thereof. A preferred synthetic anionic surfactant is a watersoluble salt of an alkylbenzene sulfonic acid containing from about 9 to about 15 carbon atoms-in the alkyl group. Another preferred synthetic anionic surfactant is a water-soluble salt of an alkyl polyethoxylate ether sulfate wherein the alkyl group contains from about 8 to about 24, preferably from about 40 to about 18 carbon atoms and there are fron about j to about 20, preferably from about : to about 12 ethoxy groups. Other suitable anionic surfactants are disclosed in U.S. Patent 4,170,565, Flesher et al., issued October 9, 1979, incorporatec herein by reference. ationic Surfactants. Suitable cationic surfactants have the general formula R2 4 YLz wherein R2 is an organic group containing a straight or branched alkyl or alkenyl group optionally substituted with up to three phenyl or hydroxy groups and optionally interruped by up to four structures selected from the group consisting of EMI6.1 and mixtures thereof, each R2c@ntaining from about 8 to 22 carbon atoms, and which may additionally contain up to about 12 ethylene oxide groups, m is a number from 1 to 3, each R3 is an alkyl or hydroxyalkyl group containing from 1 to 4 carbon atoms or a benzyl group with no more than one in a molecule being benzyl, x is a number from 0 to 11, the remainder of any carbon atom positions being filled b hydrogens, Y is selected from the group consisting of: EMI6.2 EMI6.3 wherein p is from 1 to 42 EMI7.1 wherein p is from1 to 12, EMI7.2 ±9) mixtures thereof. A more complete disclosure can be found in U.S. Patent Application Serial Number No. 919,340, by Cushman M. Cambre for Laundry Detergent Composition Having Enhanced Particulate Soil Removal and Antiredeposition Performance, filed June 2E, 197E, said application being incorporated herein by reference. Care should be taken in including cationic materials, including surfactants since some cationic materials have been founc to decrease enzyme effectiveness. Zwitterionic Surfactants. Zwitterionic surfactants include derivatives of aliphatic quaternary ammonium, phosphonium, and sulphonium compounds in which the aliphatic moiety can be straight or branched chain and wherein one of the aliphatic substituents contains from about 8 to about 24 carbon atoms and one contains an anionic water-solubilizing group. Particularly preferred zwitterionic materials are the ethoxylated ammo- nium sulfonates and sulfates disclosed in U.S. Patents 3,925,262, Laughlin et al., issued December 9, 1975 and 3,929,67E, Laughlin et al., issued December 30, 1975, said patents being incorporated herein by reference. Ampholvtic Surfactants. Ampholytic surfactants include derivatives of aliphatic heterocyclic secondary and ternary amines in which the aliphatic moiety can be straight chain or branched and wherein one of the aliphatic substituents contains from about 8 to about 24 carbon atoms and at least one aliphatic susbtituent contains an anionic water-solubilizing group. Semi-Polar Nonionic Surfactants. Semi-polar nonionic surfactants include water-soluble amine oxides containing one alkyl or hydroxy alkyl moiety of from about 8 to about 28 carbon atoms and two moieties selected rom the group consisting of alkyl groups and hydroxy alkyl groups, containing from 1 to about 3 carbon atoms which can optionally be joined into ring structures; watersoluble phosphine oxides containing one alkyl or hydroxy alkyl mciety of from about 8 to about 28 and two moieties selected from the group consisting of alkyl groups and hydroxy alkyl groups, containing from about 1 to about 3 carbon atoms and water-soluble sulfoxides containing one alkyl or hydroxy alkyl moiety of from about 8 to about 28 carbon atoms and a moiety selected from the group consisting of alkyl and hdryoxy alkyl moieties cf from : to 3 carbon atoms. For a more complete disclosure of compounds which are suitable for incorporation in detergent compositions, one can consult U.S. Patents 4,056,481 Tate (November 1, 1977); 4,049,586, Collier (September 20, 1977); 4,040,988, Vincent et al. (August 9, 1977); 4,035,257, Cherney (July 12, 1977); 4,033,718, Holcolm et al. (July 5, 4977); 4,019,999, Ohren et al. (April 26, 1977) 4,019,998, Vincent et 21. (April 26, 1977); and 3,985,669, Krummel et al. (October 12, 176), all of said patents being incorporated herein by reference. Preferred in the compositions of this invention is a binary active system consisting essentially of: an anionic synthetic surface-active salt selected from the group of sulfonates and sulfates and an ethoxylated nonionic surfaceactive agent, whereby the weight ratio cf the anionic surfaceactive salt to the nonionic ethoxylate is generally in the range from 4:1 to 3 1 and more preferably in the range from 5:2 to 3:4. Suitable anionic synthetic surface-active salts are selected from the group of sulfonates and sulfates. The like anionic detergents are eminently well-known in the detergent arts and have found wide-spread application in commercial detergents. Preferred anionic synthetic watersoluble sulfonate or sulfate salts have in their roleculEr structure an alkyl radical containing from about 8 to about 22 carbon atoms. Examples cf such preferred anionic sur factant salts are the reaction products obtained by sulfa- ting C8- C18 fatty alcohols derived from tallow and coconut cil; alkylbenzene sulfonates wherein the alkyl group contains from about 8 to 15 carbon atoms; sodium alkylglyceryl ether sulfonates; ether sulfates of fatty alcohols derived from tallow and coconut cils; coconut fatty acid monoglycerid sulfates and sulfonates; and vater-scluble salts of paraffin sulfonates having from about 8 to about 22 carbon atoms in the alkyl chain. Sulfonated olefin surfactants as more fully described in e.g. U.S Patent Specification 3,332,880, incorporated herein by reference, can also be used. The neutralizing cation for the anionic synthetic sulfonates and/or sulfates is represented by conventional cations which are widely used in detergent technology such as sodium, potassium, lithium. amines and substituted amines. Preferred are sodium, mono-, di- and tri-ethanol amines. A particularly preferred anionic synthetic surfactant component herein is represented by the water-soluble salts of an alkylbezene sulfonic acid, preferably sodium or alkanolamine alkylbenzene sulfonates having from about 10 to 13 carbon atoms in the alkyl group. A preferred class of onionic ethoxylates is repre -sented by the condensation product of a fatty alcohol having from 12 te 15 carbon atoms and from about 4 to 10 moles of ethylene oxide per mole of fatty alcohol. Suitable species of this class of ethoxylates include: the condensation product of C12-C15 ox@-alcohols and 7 moles of ethylene oxide per mcle of alcohol; the condensation product of narrow cut C14-C15 5 ox@-alcohols and 7 or 9 moles of ethylene oxide per mole of fatty (oxo) alcohol; the condensation product of a narrow cut C12-Cl3 fatty (oxo) alcohol and 6,5 moles of ethylene oxide per mole of fatty alcohol; and the condensation products of a C10-C14 coconut fatty alcohol with a degree of ethoxylation (moles EO/mole fatty alcohol) in the range from 5 to 8. The fatty oxo alcohols while mainly linear can have, depending upon the processing conditions and raw material olefinE, 2 certain degree of branching, particularly short chain such as methyl branching. A degree of branching in the range from 15% to 50% (weight %) is frequently found in commercial oxo-alcohols. Preferred nonionic ethoxylated components can also be represented by a mixture of 2 separately ethoxylated nonionic surfactants having a difère;nt degree of ethoxylation. For temple, the nonionic ethoxylate surfactant containing fro 3 to 7 moles of ethylene oxide per mole of hydrophobic moiety and S second ethoxylated species having from 8 to 14 moles of ethylene oxide per mole of.hydrophobic moiety. A preferred nonionic ethoxylated mixture contains a lower ethoxylate which is the condensation product of a C12-C15 oxoalcohol, with up to 50% (wt) branching, and from about 3 to 7 moles of ethylene oxide per mole pf fatty oxo-alcohol, and a higher ethoxylate which is the condensstion product of a C16-C49 oxo-alcohol with more than 50% (wt) branching and from about 8 to 14 moles of ethylene oxide per mole of branched oxo-alcohol. The Saturated Fatty Acid. The saturated fatty acid component herein is incorporated in an amount of from about 3%. to ahout 15p, preferably from about 5% to about 11%. The saturated fatty acids have from 10 to 16, preferably 12 or 14 carbon atoms in the alkyl chain. The most preferred fatty acids are either lauric acid or lauric and myristic fatty acid in a mixture of 5:1 to 1:1. It is understood that in addition to the saturated fatty acids, the compositions herein can comprise certain amounts of unsaturated fatty acids having, for example, 16 or 18 carbon atoms in the alkyl chain. Known examples of the like unsaturated fatty acids are oleic fatty acid and palmitoleic fatty acid. The Enzyme. The enzyme component herein is incorporated in an amount of from about 0.025 to about 1%, preferably from about 0.05% to about 0.2. The preferred proteolytic enzyme component should give to the composition 2 proteolytic activity of at least about 4 arson units, preferably from. about 8 to about 30 Anson units, most preferably from about 10 to about 20 Anson units per kilo of the liquid detergent composition. In another preferred embodiment the enzyme component can be represented by a mixture of proteases and amylases. The proteolytic activity of that mixture is as defined herein before Preferably the enzyme component is characterized by an inoelectric point of from about P.0 to about to, preferably from about 8.5 to about 9.5. Examples of suitable proteolytic enzymes include many -specles which are known to be adpated for use in detergent compositions and, in fact, have been used in detergent compositionst Sources of the enzymes include commercial enzyme preparations such as "ALCALASE' sold by Novo Industries, and "MAXATASE sold by Gist-Brocades, Delft, The Netherlands, which contain about 20; enzyme. Other preferred enzyme compositions include those commercially available under the tradenames SP-72 ("Esperase") manufactured and sold by Novo Industries, A/S, Copenhagen, Denmark and "AZ-Protease" manufactured and sold by Gist-Erocades, Delft, The Netherlands. A more complete disclosure of suitable enzymes can be found in U.S. Patent 4,101,457, Place et al., issued July 18, 1978, incorporated herein by reference. The Carboxylic Acid. A further essential component herein is represented by a short chain carboxylic acid having from 1 to 3 carbon atoms. This ingredient is used in an amount from 0.1% to about 3%, preferably from 0,5 to 1,5 by weight. The carboxylic acid component can be represented by formic, acetic and propionic acid. Preferred are the water-soluble salts. Nost preferred is formic acid or the formates such as sodium, potassium, lithium, amines and substituted amines, inclusive of mono-, di-, and tri-ethanolamines. The Enzyme-Accessible Calcium. The compositions herein comprise less than about 2, preferably from 0.5 to 1.5, millimoles of enzyme-accessible calcium per kilo of the homogeneous enzyme containing detergent product. The claimed compositions are substantially free of sequestrants for example, polyacids capable of forming calcium complexes which are soluble in the composition. However, minor amounts of sequestrants such as polyacids or mixtures of polyacids can be used. The enzyme-accessible calcium is defined as the amount of calcium-ions effectively available to the enzyme component. The calcium sequestration resulting from e.g., 055 of a mixture of polyphosphonates and polyacids as exemplified hereinafter can represent about 1 to about 1.5 millimoles of calcium per kilo of product. The total calcium incorporated into the compositions is thus comprised of the enzyme-accessible calcium and also the calcium sequestered by the low levels of polyacids. From a practical standpoint the enzyme-accessible calcium is therefore the soluble calcium in the composition in the absence of any strong sequestrants, e.g., having an equilibrium constant of complexation with calcium equal to or greater than 1.5 at 200C. Product pH. The pH of the product is from about 6.5 to about 8.5 preferably from about 7 to about 7.5 to obtain a combination of enzyme stability and detergency. Both high and low pH's can adversely affect enzyme stability. Optional Components. In addition to the essential ingredients described hereinbefore, the compositions herein frequently contain a series of optional ingredients which are used for the known functionalit in conventional levels. While the inventive compositions are premised on aqueous enzyme-containing detergent compositions containing a critical ternary system as fully explained above, it is frequently desirable to use 2 phase regulant This component together with water constitutes then the solvent matrix for the claimed liquid compositions. Suitable phase regulants are well-known in liquid detergent technology and, for example, can be represented by lower aliphatic alcohols having from 2 to 6 carbon atoms and from 1 to 3 hydroxyl groups, ethers of ethylene glycol and lower aliphatic monoalcohols having from 4 to 4 carbon atoms. Specific examples of phase regulants are: ethanol; n-propancl; isopropanl; butanol; 1,2-propanediol; 1,3-propnediol; n heanol; monomethyl-, -ethyl-, -propyl, and mono-butyl ethers and di-ethylene glycol. Additional phase regulants having a relatively high boiling point and low vapor pressure can also be used provided they duo not react with the other ingredients of the compositions. Known detergent hydrotropes are a further class of phase regulants suitable for use herein. Examples of these hydrotropes include salts of alkylarylsulfonates having up to 3 carbon atoms in the alkylgroup, e.g., sodium, potassium, ammonium and ethanolamine salts of xylene-, toluene-, ethylbenzene-, cumene-, and isopropylbenzene sulfonic acids. The phase is frequently used in an amount from about 5 to about 20%; the sum of phase regulant and water is normally in the range from 65% to 35%. The compositions herein can contain a series of further optional ingredients which are mostly used in additive levels, usually below about 5%. Examples of the like additives include: polyacids, suds regulants, opacifiers, antioxidants, bactericides, dyes, perfumes, brighteners and the like. A preferred additive is represented by a polyacid or mixture of polyacids in an amount below about 1%. Suitable polyacids can include: citric, cyclohexane-1,1-dicarboxylic, cyclopropane-1,1-dicarboxylic, dimethylmalic, glutaric, ohydroxybenzoic, m-hydroxybenzoic, p-hydroxybenzoic, itaconic, methylsuccinic, sodium: tripolyphosphates, and nitrilotriacetic acid. Preferred polyacid species for use herein can be represented by citric acid and organo-phosphonic acids and mixtures thereof. Particularly preferred alkylene-polyaminopolyalkylene phosphonic acids are ethylene diamine tetramethylenephosphonic acid, hexamethylene diaminetetramethylene- phosphonic acid, diethylene triaminepentamethylenephosphonic acid, and amino-trimethylenephosphonic acid or the salts thereof, These organophosphonic acids/salts are preferably used in an amount from 0.1%-0.8%. The beneficial utilization of the claimed compositions under various usage conditions can require the utilization of a suds regu)ant.. While generally all detergent suds regulants can be utilized preferred for use herein are alkylated polysiloxanes such as dimethylpolysiloxane also frequently termed silicone. The silicones are frequently used in a level not exceedingg 0.5%, most preferably between 0.01% and 0.2%. It can also be desirable to utilize opacifiers inasmuch as they contribute to create a uniform appearance of the concentrated liquid detergent compositions. Examples of suitable opacifiers include: polystyrene commercially known as LYTRON 621 manufactured by MONSANTO CHEMICAL CORPORATION. The opacifiers are frequently used in an amount from 0,3% to 1,5°. The compositions herein can also contain known antioxidants for their known utility, frequently radical scavengerms, in the art established levels i.e. 0,001% to 0,25% (by reference to total composition). These antioxidants are frequently introduced in conjunction with the fatty acids. Awhile many suitable antioxidants are readily known and available for that purpose especially preferred for use in the compositions herein are: 2,6 ditertiary butyl-p-cresol, more commonly known as butylated hydroxytoluene, BHT, and 2 tertiarybutyl-4-hydroxyanisole or 3-tertiarybutyl-4-hydroxy- anisole more commonly known as BHA or butylated hydroxyanisole. Other suitable antioxidants are: 4,4tthiobis(6-tert-butyl-m- cresol) and 2-methyl-4,6-dinonyl phenol. The following examples illustrate the invention and facilitate its understanding. EXAMPLE Liquid detergent compositions were prepared by mixing the listed ingredients in the stated proportions. EMI15.1 <tb> <SEP> INGREDIENTS <SEP> COMPOSITIONS <tb> <SEP> A <SEP> BC <SEP> <tb> Linear <SEP> dodecylbenzene <SEP> sulfonic <SEP> acid <SEP> S4 <SEP> 14 <SEP> 14 <SEP> 14 <tb> Condensation <SEP> product <SEP> of <SEP> one <SEP> mole <SEP> of <tb> C13-C15 <SEP> OXO <SEP> alcohol <SEP> and <SEP> 7 <SEP> moles <SEP> of <tb> ethylene <SEP> oxide <SEP> 30 <SEP> 15 <SEP> 15 <SEP> 15 <tb> EMI16.1 <tb> Lauric <SEP> acid <SEP> - <SEP> 10 <SEP> 40 <SEP> <SEP> io <SEP> <tb> 0Zeic <SEP> acid <SEP> - <SEP> 5 <SEP> 5 <SEP> 5 <tb> Triethanolamine <SEP> 8.5 <SEP> 5 <SEP> 5 <SEP> 5 <tb> Sodium <SEP> hydroxide <SEP> to <SEP> adjust <SEP> pH <SEP> to: <SEP> 7 <SEP> 7 <SEP> 7 <SEP> 7 <tb> Ethanol <SEP> 10 <SEP> 10 <SEP> 10 <SEP> 10 <tb> 1,2 <SEP> propanediol <SEP> 4 <SEP> 4 <SEP> 4 <SEP> 4 <SEP> <tb> Proteolytic <SEP> enzyme <SEP> (a) <SEP> 0.05 <SEP> 0.05 <SEP> 0.05 <SEP> 0.05 <tb> Calcium <SEP> (b) <SEP> (c) <SEP> 4 <SEP> 4 <SEP> 2.0 <SEP> 2.0 <tb> Sodium <SEP> formate <SEP> - <SEP> - <SEP> - <SEP> 1.0 <tb> Citric <SEP> acid <SEP> 0.2 <SEP> 0.2 <SEP> 0.2 <SEP> 0.2 <tb> Diethylenetriamine <SEP> pentaphosphonic <tb> <SEP> acid <SEP> 0.3 <SEP> 0.3 <SEP> 0.3 <SEP> 0.3 <tb> Silicone <SEP> suds <SEP> regulant <SEP> emulsion, <SEP> <tb> brightener, <SEP> perfume, <SEP> opacifier, <tb> dye, <SEP> antioxidant <SEP> and <SEP> water <SEP> B <SEP> A <SEP> L <SEP> A <SEP> N <SEP> C <SEP> E <SEP> TO <SEP> 100 <tb> (a) MAXATASE# supplied by GIST-BROCADES expressed on a 100% active basis. (b) Added as calcium chloride and expressed as millimoles of calcium ion per kilo of composition. (c) The level of enzyme-accessible calcium is: composition A:2,5; B : 2,5; C : C.5 and I : 0.5. The enzyme and physical stability of the listed compositions were determined under accelerated storage conditions after 2 weeks at 350C. Composition A is representative of the prior art. Compositions E and C are reference compositions based on routine variations vs. the art compositions. Cor:position I is an example of the invention herein. The level of calcium in compositions A and B represents, based on current art knowledge, the minimum needed to achieve acceptable enzyme stability. The amount of calcium in composition C was lowered to the point where phase instahility and precipitation would not anymore occur. The testing data are summarized below. EMI17.1 <tb> <SEP> COMPOSTTION <tb> <SEP> B <SEP> C <tb> Residual <SEP> enzyme <SEP> <tb> <SEP> Stability <SEP> after <SEP> 2 <SEP> weeks <SEP> 48 <tb> <SEP> at <SEP> 35 C <SEP> (%) <SEP> 66 <SEP> 42 <SEP> 18 <SEP> 85 <tb> Product <SEP> appearance <SEP> precipi- <SEP> precipi- <SEP> clear <SEP> clear <tb> <SEP> tatian <SEP> tation <tb> These results confirm the overall performance benefits provided by composition I in accordance with this invention vs. formulationwise closely related art composition --A-- or what could be technical variations --B, C-- of known art formulations. Comparable performance benefits are obtained fro the above compositions wherein the formic acid is replaced with an identical molar proportion of acetic acid or propionic acid. further compositions of this invention were prepared b mixing the listed components in the indicated proportions. EMI17.2 <tb> <SEP> INGREDIENTS <SEP> COMPOSITIONS <tb> <SEP> D <SEP> II <SEP> III <tb> Linear <SEP> dodecylbenzene <SEP> sulfonic <SEP> acid <SEP> 14 <SEP> 14 <SEP> 14 <SEP> <tb> Condensation <SEP> product <SEP> of <SEP> one <SEP> mole <SEP> of <tb> <SEP> C13-C15 <SEP> OXO <SEP> alcohol <SEP> with <SEP> 35% <SEP> of <tb> branching <SEP> and <SEP> 7 <SEP> moles <SEP> of <SEP> ethylene <SEP> <tb> <SEP> oxide <SEP> 15 <SEP> 15 <SEP> <SEP> 45 <SEP> <tb> Lauric <SEP> acid <SEP> 10 <SEP> 10 <SEP> 10 <tb> Oleic <SEP> acid <SEP> 5 <SEP> 5 <SEP> 5 <tb> Triethanolamine <SEP> 5 <SEP> 5 <SEP> 5 <tb> Sodium <SEP> hydroxide <SEP> to <SEP> adjust <SEP> U <SEP> to: <SEP> 7 <SEP> 7 <SEP> 7 <tb> Ethanol <SEP> 40 <SEP> 40 <SEP> <tb> 1,2 <SEP> propylene <SEP> glycol <SEP> 4 <SEP> 4 <SEP> 4 <SEP> <tb> EMI18.1 <tb> Proteolytic <SEP> enzyme <SEP> (a) <SEP> 0.05 <SEP> 0.05 <SEP> 0.05 <SEP> <tb> Calcium <SEP> (b) <SEP> 4.5 <SEP> 4.5 <SEP> 1.5 <SEP> <tb> Formic <SEP> acid <SEP> (c) <SEP> - <SEP> 0.68 <SEP> <tb> Acetic <SEP> acid <SEP> (c) <SEP> - <SEP> - <SEP> 0.88 <tb> Citric <SEP> acid <SEP> 0.2 <SEP> 0.2 <SEP> o.3 <SEP> <tb> Diethanolamine <SEP> pentaphosphonic <SEP> acid <SEP> 0.3 <SEP> Q.3 <SEP> o.3 <SEP> <tb> Silicone <SEP> suds <SEP> regulant <SEP> emulsion, <tb> <SEP> brightener, <SEP> perfume, <SEP> opacifier, <tb> <SEP> dye, <SEP> antioxidant <SEP> and <SEP> water <SEP> B <SEP> A <SEP> L <SEP> A <SEP> N <SEP> C <SEP> E <SEP> TO <SEP> 100 <tb> (a) MAXATASE # supplied by GIST-BROCADES and expressed on a 100% active. basis (b) Total calcium added as calcium chloride and expressed in millimoles of calcium ion per liter of solution. Composition D is what could be a technical variation of the state of art whereas formulae II and III are executions of the claimed invention. The residual enzymatic activity (expressed in % of initial activity were measured following exposure to accelerated storage conditions (48 hours at 400C). The testing results were as follows: EMI18.2 <tb> <SEP> Compositions <SEP> <tb> <SEP> D <SEP> II <SEP> III <SEP> <tb> Residual <SEP> enzymatic <tb> actiyity <SEP> (in <SEP> %) <SEP> 25 <SEP> 64 <tb> These results verify the. superiority of the claimed technology @s. closely related compositions and also show that formic acid is the most preferred short chain carboxylic acid, A series of additional compositions of this invention are prepared by mixing the listed ingredients in a conventional manner. EMI19.1 <tb> <SEP> INGREDIENTS <SEP> COMPOSITIONS <tb> <SEP> IV <SEP> V <SEP> VI <SEP> VII <SEP> VIII <SEP> IX <SEP> X <tb> Linear <SEP> dodecylbenzene <tb> sulfonic <SEP> acid <SEP> 14 <SEP> 6 <SEP> 14 <SEP> 14 <SEP> 10 <SEP> 14 <SEP> 14 <tb> Condensation <SEP> product <SEP> of <SEP> one <tb> -mole <SEP> of <SEP> C14 <SEP> C15 <SEP> aXO <SEP> alcohol <tb> with <SEP> 20% <SEP> branching <SEP> and <SEP> 7 <tb> moles <SEP> of <SEP> ethylene <SEP> oxide <SEP> 20 <SEP> 30 <SEP> - <SEP> - <SEP> - <SEP> 20 <SEP> <tb> Condensation <SEP> product <SEP> of <SEP> one <tb> mole <SEP> of <SEP> C13-C15 <SEP> OXO <SEP> alcohol <tb> with <SEP> 25% <SEP> branching <SEP> and <SEP> 4 <tb> moles <SEP> of <SEP> ethylene <SEP> oxide <SEP> - <SEP> - <SEP> - <SEP> 5 <SEP> - <SEP> - <SEP> <tb> Condensatibn <SEP> product <SEP> of <SEP> one <tb> mole <SEP> of <SEP> C16-C19 <SEP> <RTI ID=19.2> OXO <SEP> alcohol <tb> highly <SEP> branched <SEP> (60%) <SEP> and <tb> 11 <SEP> moles <SEP> of <SEP> ethylene <SEP> oxide <SEP> - <SEP> - <SEP> - <SEP> 10 <SEP> - <SEP> | <SEP> - <SEP> <tb> Condensation <SEP> product <SEP> of <SEP> one <tb> mole <SEP> of <SEP> C13-C15 <SEP> OXO <SEP> alcohol <tb> with <SEP> 35% <SEP> branching <SEP> and <SEP> 7 <tb> moles <SEP> of <SEP> ethylene <SEP> oxide <SEP> - <SEP> - <SEP> 20 <SEP> - <SEP> 15 <SEP> - <SEP> 20 <tb> Lauric <SEP> acid <SEP> 10 <SEP> 10 <SEP> 5 <SEP> 5 <SEP> - <SEP> - <SEP> <tb> Coconut <SEP> acid <SEP> (hardened <SEP> & <tb> stripped) <SEP> (a) <SEP> - <SEP> - <SEP> - <SEP> - <SEP> 10 <SEP> 5 <SEP> 10 <tb> Oleic <SEP> acid <SEP> 5 <SEP> - <SEP> 8 <SEP> 8 <SEP> 5 <SEP> 10 <SEP> 5 <tb> Proteolytic <SEP> enzyme <SEP> (b) <SEP> 0.05 <SEP> 0.05 <SEP> 0.05 <SEP> 0.05 <SEP> 0.05 <SEP> 0.05 <SEP> 0.05 <SEP> <tb> Calcium <SEP> (c) <SEP> 1.5 <SEP> 2 <SEP> 1.6 <SEP> 2.0 <SEP> 1.5 <SEP> 0.5 <SEP> 1.0 <tb> Sodium <SEP> formate <SEP> 1.0 <SEP> 1.5 <SEP> 1.0 <SEP> 0.5 <SEP> 1.0 <SEP> 0.5 <SEP> 1.0 <tb> Triethanelamine <SEP> 5 <SEP> 5 <SEP> 5 <SEP> 5 <SEP> 5 <SEP> 5 <SEP> 5 <tb> Sodium <SEP> hydroxide <SEP> up <SEP> to <SEP> pH <SEP> 7 <SEP> 7 <SEP> 7 <SEP> 7.5 <SEP> 6.8 <SEP> 7 <SEP> 7 <tb> Citric <SEP> acid <SEP> 0.2 <SEP> 0.2 <SEP> 0.2 <SEP> 0.2 <SEP> Q.2 <SEP> 0 <SEP> 0 <SEP> <tb> Diethanolamine <SEP> penttaphos <tb> phonic <SEP> acid <SEP> 0.3 <SEP> 0.3 <SEP> 0.3 <SEP> 0.3 <SEP> 0.3 <SEP> 0 <SEP> 0.3 <tb> Ethanol <SEP> 12 <SEP> 12 <SEP> 12 <SEP> 12 <SEP> 12 <SEP> 12 <SEP> 12 <tb> EMI20.1 <tb> Silicone <SEP> suds <SEP> suppressor <tb> emulsion, <SEP> brightener, <SEP> per- <tb> fume, <SEP> opacifier, <SEP> dye, <SEP> anti <tb> oxidant <SEP> and <SEP> water <SEP> B <SEP> A <SEP> L <SEP> A <SEP> N <SEP> C <SEP> E <SEP> T <SEP> O <SEP> 100 <tb> (a) Coconut fatty acid having a ratio : lauric to myristic acid of 70 to 30. (b) MAXATASE# supplied by GIST-BROCADES expressed on 100% active enzyne-basis. (c) Total calcium is expressed as millimoles of calcium per kilo of composition and added as calcium chloride. Compositions IV - X are clear, homogeneous products having a markedly improved enzyme stability, especially upon storage.

Claims: CLAIMS 1. A homogeneous aqueous liquid detergent composition comprising: (a) from about 20; to about 50% by weight of an organic synthetic surface-active agent; (b) from about 3% to about 15% by weight of a saturated fatty acid having 10 to 16 carbon atoms in the alkyl chain; (c) from 0.025% to about 1% by weight of an enzyme; (d) from 0.1% to about 3% by weight of a carboxylic acid having from 1 to 3 carbon atoms; and (e) less than 2 millimoles of enzyme-accessible calcium per kilo of the detergent composition, the pH of the composition, measured as is at 200C, being from 6.5 to 8.5. 2. The composition in accordance with Claim 1 wherein the fatty acid has from 12 to 10 carbon atoms in the alkyl chain. 3. The composition in accordance with Claim 1 wherein the enzyme is selected from the group of proteases and mixtures of proteases and amylases and is present in a level from 0.04 @ to 0.4 by weight. 4. The composition in accordance with Claim 1 wherein the carboxylic acid is represented by formic acid and is present in a leel from 0.5% to 1,5 by weight. 5. The composition in accordance with Claim 1 wherein the enzyme-accessible calcium is present in an amount fro 0.5 to 1.5 millimoles per kilo of the detergent composition. 6. The composition in accordance with Claim 1 having a pH in the range from about 7 to 7.5. 7. The composition in accordance with. Claim 1 which in addition contains a phase ragulant in an amount from about 5% to about 20% by weight. 8. The composition in accordance with Claim n which in addition contains. up to 4% hy weight of a polyacid selected from the group consisting of: citric acid, alkylene-polyaminopolyalkylene phosphonic acids and mixtures thereof. 9. The composition in accordance with Claim 1 which in addition contains from Q.01 to 0.2% by weight of a silicone suds-regulant. 40. The composition in accordance with Clam 8 wherein the alkylene-polyamino-polyalkylene phosphonic acid is selected from the grout- consisting of ethylenediaminetetramethylene phosphonic, hexamethylenediamine tetr2methylene phosphonic, diethylenetriaminepentamethylene phosphonic and aminotrimethylenephosphonic acids and the salts thereof and is present in an amount of from 0.1% to 0.8% by weight.

Inventors: BARRAT, CHRISTIAN ROLAND, TOLFO, FLAVIO
Applicants: PROCTER & GAMBLE EUROPEAN TECHNICAL CENTER, THE PROCTER & GAMBLE COMPANY
Application year: 1980
Main classification: C11D3
IPC codes: C11D3