BE898436A - Liquid detergent composition containing a mixture of enzymes and method of washing the laundry using it. - Google Patents

Abstract

Liquid detergent composition containing a mixture of enzymes and methods for washing the laundry using it; the composition comprises: (a) 5 to 75% of one or more detergent surfactants, preferably 10 to 60% of a nonionic detergent compound which is an alkoxylated (C10-C18) alkoxylated (C2-C3), (b) 25 to 85% water, and (c) a mixture of enzymes consisting essentially of an alkaline protease and an alpha-amynase in the relative proportions such that the ratio of the enzymatic activities in said mixture is from approximately 4,000 to approximately 80,000 units of Novo alpha-amylase amylase per Anson unit of protease.

Description

       

    <Desc / Clms Page number 1>
   bescription attached to a request for
BELGIAN PATENT filed by the company known as: COLGATE-PALMOLIVE COMPANY having for object: Liquid detergent composition containing a mixture of enzymes and method of washing clothes 1 'using Qualification proposed: PATENT OF INVENTION
 EMI1.1
 Priority of a patent application filed in the United States
 EMI1.2
 of America on December 13, 1982 under the nV,
 EMI1.3
 
 EMI1.4
 

  <Desc / Clms Page number 2>

 
The present invention relates to a liquid detergent composition containing a mixture of enzymes and a method for washing the laundry using it.



   In general, the invention relates to liquid detergent compositions containing enzymes which are suitable for washing or pre-soaking laundry.



  More particularly, the invention relates to detergent compositions containing mixtures of protease and amylase enzymes in defined proportions which ensure a particularly effective removal of dirt from stains when washing the laundry.



   Much attention has been paid in the prior art to liquid detergent compositions containing enzymes.



  It is desirable to incorporate enzymes into detergent compositions, mainly because of the effectiveness of proteolytic and amylolytic enzymes in breaking down protein and starchy materials present on soiled tissue to facilitate the removal of stains, such as stains of sauce, blood, chocolate and others, when washing. However, the enzyme materials
 EMI2.1
 suitable for washing compositions, especially. proteolytic enzymes, are relatively expensive. In fact, these are generally the most expensive components of a typical commercial liquid detergent composition even when present in relatively small amounts. In addition, an excess of enzymes is generally necessary in the detergent composition.

   Due to the known instability of enzymes in aqueous compositions, an excess of enzymes is generally added to the composition to compensate for the expected loss of enzyme activity during extended periods of storage. Consequently, the cost of using enzymes in liquid detergent compositions has hitherto notably slowed down the generalization of their commercial use.



   Detergent compositions containing mixtures

  <Desc / Clms Page number 3>

 ges of enzymes, for example proteases and amylases have been abundantly described in the prior art. For example, US Pat. No. 3,630,930 describes a granular detergent composition containing from approximately 0.5 to 20% of enzyme-carrying granules, the enzyme granules consisting of approximately 0.001 to 10% of enzyme mixtures. protease and amylase in a weight ratio of protease to amylase from 50/1 to 1/5. British Patent 1,240,058 describes a granular detergent composition containing a mixture of protease and amylase enzymes in a weight ratio of protease to amylase of 30/1 to 3/1, the weight percentage of amylase in the composition being from 0.0003 to 3-%. The
 EMI3.1
 ..

   US 3,931,034 describes a granular detergent composition containing a mixture of alkaline protease enzymes and α-amylase in an activity ratio varying between 100,000 and 400,000 units of Novo amylase amylase per Anson unit of protease.



   Therefore, although the use of mixtures of enzymes in granular detergent compositions is described generally in the patent literature, their mixtures are, in most cases, described so generally that it includes example of mixtures in which the percentage of protease can vary by 5 orders of magnitude (British patent 1240058) or the percentage of amylase can vary by 5 orders of magnitude (US patent 3 630 930), which suggests that in these extended ranges, the greater the quantity of enzymes used, the more effective the stain removal obtained.

   In addition, the aforementioned patents, de. as well as US patent 3,931,034, strictly relate to granular compositions and therefore do not provide any teaching relating to the use of mixtures of enzymes in liquid compositions.



   The invention provides a liquid detergent composition containing enzymes comprising:

  <Desc / Clms Page number 4>

 (a) about 5 to about 75% by weight of one or more detergent surfactants chosen from anionic, nonionic, cationic, ampholytic and zwitterionic detergent compounds; (b) about 25 to 85% water; and (c) a mixture of enzymes essentially consisting of an alkaline protease and an α-amylase in relative proportions such that the ratio of the enzymatic activities is from approximately 4,000 to approximately 80,000 units of Novo amylase from α-amylase per Anson unit of the protease, said protease being present in an amount providing approximately 0.25 to approximately 2.5 Anson units per 100 g of composition. detergent.



   According to the process of the invention, stained and / or soiled articles are washed by contact of these articles with an aqueous solution of the liquid detergent composition defined above.



   The invention is based on the discovery that the amount of alkaline protease enzyme which is normally required to remove protein stains can be clear-
 EMI4.1
 ment reduced by combination with an amount of enzyme, amylase according to the invention so as to provide a detergent composition having equivalent or improved stain removal capabilities but considerably less harsh. Contrary to the descriptions of the art which recommend mixing proteases and amylases in wide ranges in detergent compositions, the enzyme mixtures described here are characterized by a synergistic interaction of protease and amylase and only cover mixtures whose activity report is closely defined.



   The activities of the alkaline protease and α-amylase enzymes are expressed respectively in Anson units for the protease and in Novo amylase units for the amylase.



  These are units commonly used in the art for

  <Desc / Clms Page number 5>

 
 EMI5.1
 describe the activity, under ordinary conditions, of enzyme positions containing protease or amylase enzymes.



   In a preferred embodiment of the invention, the mixtures of enzymes contain relative amounts of alkaline protease and α-amylase providing approximately 10,000 to 50,000 units of Novo α-amylase amylase per Anson unit protease, an activity ratio of about 15,000 to 40,000 being even preferred and a ratio of about 30,000 to 40,000 being particularly desirable.



   The amount of enzyme mixture present in the liquid detergent composition depends of course to some extent on the amount of composition added to the washing solution. For detergent compositions intended to be used at concentrations of approximately 0.15% in the washing solution of a domestic automatic washing machine, an appropriate amount of mixture provides approximately 0.25 to approximately 2.5 units. Anson of protease per 100 g of detergent composition, a ratio of about 0.5 to 2.0 being preferred, and about 1.5 Anson units / 100 g of composition being a particularly preferred protease concentration.



   The invention will now be described in detail.



   The activity of the alkaline protease enzyme is as indicated above measured in Anson units. Anson's hemoglobin method for measuring the unit of activity Anson is a technique well known in the art for determining the activity of proteolytic enzymes and it appears in "Journal of General Physiology", volume 22, pages 79-89 (1939). The modified Anson's hemoglobin method can also be used to measure proteolytic activity, this modified method being described in the article "Alkali-Resistant Enzyme for Detergents", by SR Green, Soap and Chemical Specialties, pages 86 , 88, 90, 94 and 133,

  <Desc / Clms Page number 6>

 May 1968.

   In principle, the method uses the enzyme alkaline protease to digest a substrate consisting of denatured hemoglobin under standard conditions in an aqueous medium buffered to the chosen pH, and the amount of material digested is determined by a colored reaction with a phenolic reagent.



   The activity of the enzyme α-amylase is, as previously indicated, measured in units of Novo amylase.



  The standard measurement technique for these Novo units is a modification of the SKB method (Sandstedt, Kneen & Blish, Cereal Chemistry 16,712, (1939)) without the addition of P-amylase. In this technique, we measure in a tube. test (diameter 24 mm, length 190 mm) 20 ml of a buffered starch solution (prepared according to the method described below) and placed in a thermostat water bath at 37 ° C.



  After a few minutes of preheating, 10 ml of the amylase solution to be analyzed (or v ml of amylase solution + (10-v) ml of water) are added. The contents of the tube are carefully mixed and at the same time a stopwatch is started. At appropriate intervals, 1 ml of the reaction mixture is added to 5 ml of a dilute iodine solution (prepared according to the method described below), the mixture is stirred and transferred to a comparison tube and the color is compared with standard color. If the final coloration is reached in less than 10 minutes, a more dilute amylase solution or a lower volume of amylase solution is used.



   As a colorimeter, the Comparator 607 Hellige is used with the a-amylase glass standard (cf. RedfernMethods for determination of a-amylase, Cereal Chemistry 24, 259, (1947)). The α-amylase activity of the sample can be calculated with the following formula:
 EMI6.1
 A 1,430 x in which: A-txaxv
 EMI6.2
 A = α-amylase activity in Novo amylase units per gram

  <Desc / Clms Page number 7>

 t = time required to obtain the final color (minutes) a = weight of the sample in grams V = volume to which the sample is diluted (ml) v = volume of the amylase solution used (ml)
The factor "1430" is not strictly constant, but depends to some extent on the quality of the starch used.

   For exact determinations, the factor value should be calculated using a standard commercial amylase preparation with known activity.



   The aforementioned "diluted iodine solution" is prepared by dissolving 1 ml of "iodine stock solution" and 20 g of potassium iodide in enough water for the volume to be 500 ml; the "iodine stock solution" is prepared by dissolving 11 g of iodine crystals and 22 g of potassium iodide in sufficient water so that the volume is 500 ml.



     The "buffered starch solution" mentioned above is prepared in the following way: 10 g of soluble starch are suspended in a little water (for example Merck, Amylum solubile, Soluble Starch, Erg. B. 6) calculated as dry matter. The suspension is added to approximately 200 ml of boiling water. When the starch is completely dissolved, the solution is cooled, transferred to a 1-liter volumetric flask and the mixture is adjusted to the mark with water.



   The starch solution (prepared by dissolving 9.36 g of NaCl, 69.00 g of KH2P04'4, 80 g of Na2HP04'2H20 in sufficient water so that the volume is 1 liter).



  Finally, the solution is saturated with toluene. The pH of the final buffered starch solution should be 5.7. - The starch solution should be as freshly prepared as possible, but can be stored in the refrigerator for up to 24 hours. In all cases, distilled water is used.



   In practice, the enzymatic activity of preparations of proteolytic enzymes is usually determined.

  <Desc / Clms Page number 8>

 and amylolytics without performing the assay operations described above. For the majority of commercial liquid enzymatic preparations containing protease or amylase enzymes, the enzymatic activity is mentioned by the manufacturer and is expressed in Anson units or in Novo amylase units (or in units which are directly proportional to them). Otherwise the activity of a given enzyme preparation can be easily determined by analysis according to a technique in which the reactivity of the enzyme vis-à-vis a protein or starch substrate, as the case may be, is measured in standard conditions and then compared to the reactivity of enzyme preparations of known activity reference.

   In such an analytical technique, the enzymatic reactivity can be expressed in a practical way by the optical density of a test solution containing the enzymatic preparation and the protein or starch substrate measured under standard conditions, the activity increasing with optical density.



   Suitable alkaline proteolytic enzymes include various liquid enzyme preparations
 EMI8.1
 which have been adapted for use in; detergent compositions, the powdered enzyme preparations also being useful, although as a general rule they are less practical to incorporate into the liquid detergent compositions of the invention. So suitable liquid enzyme preparations include "Alcalase" and "Esperase" sold by Novo Industries, Copenhagen,
 EMI8.2
 Denmark, and "Maxatase" and by Gist-Brocades, Netherlands. "Alcalase" is the "AZ-Protease" sold most preferred in the compositions of: the invention.



   Among the liquid enzyme preparations
 EMI8.3
 suitable a-amylase, include those sold by Novo Industries and Gist-Brocades under the brand names of "Termamyl" and "Maxamyl", respectively.



  We preferably use an organic solvent in

  <Desc / Clms Page number 9>

 combination with water serving as solvent for the liquid detergent composition. The preferred organic solvent is a lower alkanol of 1 to 4 carbon atoms having 1 to 3 hydroxy groups, preferably 1 or 2. Most preferably, the lower alkanol is ethanol or a mixture of ethanol and isopropanol, lower monoalcohols such as propanol and butanol and lower polyols having 2 or 3 carbon atoms, such as ethylene glycol and propylene glycol being useful although less preferred.



   The use of primary, secondary or tertiary butanol or n-propanol as the lower alkanol is. generally limited to mixtures of these with ethanol, ethanol preferably constituting at least 80 to 90% of these mixtures. It is much preferred to use ethanol as the sole alkanol and organic solvent. In mixtures of ethanol and isopropanol, it is preferred that ethanol is the main component, ethanol generally constituting 60 to 90% of the mixture and preferably about 75% (i.e. a ratio of 3/1). Of course, other mixtures of the various alkanols, such as ethanol and propylene glycol, can be used, and in these mixtures it is also preferred that ethanol is the main component.



   The compositions of the invention contain one or more surfactants chosen from the group of anionic, nonionic, cationic, ampholytic and zwitterionic detergent compounds. The synthetic organic detergents used in the practice of the invention may be any of these many various compounds which are well known and described in detail in the text Surface Active Agents, Vol. II, by Schwartz, Perry and Berch, published in 1958 by Interscience Publishers.



   Nonionic detergents are generally lipophilic compounds polyalkoxylated by lower alkoxy groups in which the hydrophilic-lipophilic balance

  <Desc / Clms Page number 10>

 desired is obtained by adding a hydrophilic lower polyalkoxy group to a lipophilic moiety. In the compositions of the invention, the nonionic detergent used is preferably a higher alkanol polyalkoxylated by lower alkoxy groups in which the alkanol has 10 to 18 carbon atoms and the number of modes of lower alkylene oxide (of 2 or 3 carbon atoms) is 3 to 12.



  Among these materials, it is preferred to use those in which the higher alkanol is a higher fatty alcohol of 11 or 12 to 15 carbon atoms and which contains from 5 to 8 or 5 to 9 lower alkoxy groups per mole. Preferably, the lower alkoxy is an ethoxy but in some cases it can be desirably mixed with a propoxy, the latter, when it is present, generally being a minor constituent (less than 50%). Examples of such compounds are those in which the alkanol has 12 to 15 carbon atoms and which contain about 7 ethylene oxide groups per mole, for example Neodol (R) 25-7 and Neodol 23-6.5, these products being manufactured by Shell Chemical Company, Inc.

   The first is a product of condensation
 EMI10.1
 of a mixture of higher fatty alcohols having on average t about 12 to 15 carbon atoms with about 7 moles of ethylene oxide and the second is a corresponding mixture in which the higher fatty alcohol contains 12 to 13 carbon atoms carbon and the average number of ethylene oxide groups per mole is about 6.5. Higher alcohols are primary alkanols. Other examples of these detergents include Tergitol (R) 15-S-7 and Tergitol 15-S-9 which are both linear secondary alcohol ethoxylates manufactured by Union Carbide Corporation.

   The first is a mixed ethoxylation product of a linear secondary alkanol of 11 to 15 carbon atoms with 7 moles of ethylene oxide and the second is a similar product but in which 9 moles of ethylene oxide have reacted.



   Non-ionic molecular weight compounds

  <Desc / Clms Page number 11>

 higher, such as Neodol 45-11, are also useful in the compositions of the invention and are similar condensation products of ethylene oxide and higher fatty alcohols, the higher fatty alcohol having 14 at 15 carbon atoms and the number of ethylene oxide groups per mole being about 11. These products are also manufactured by Shell Chemical Company. Other useful nonionic compounds are represented by Plurafac B-26 (BASF Chemical Company) which is the product of the reaction of a higher linear alcohol and a mixture of ethylene and propylene oxides.



   In the higher alkanols polyalkoxylated by preferred lower alkoxy groups, the best balance of hydrophilic and lipophilic moieties is obtained when the number of lower alkoxy is between about 40% and 100% of the number of carbon atoms of the higher alcohol, preferably between 40 and 60%. The nonionic detergent preferably consists of at least 50% of the preferred ethoxylated alkanols.

   Higher molecular weight alkanols and various other normally solid non-ionic detergent and surfactant compounds may contribute to gelation of the liquid detergent composition and therefore are normally excluded or are present only in limited amounts in the compositions of the invention. invention, although small proportions can be used due to their cleaning properties, etc.



  As regards the preferred and less preferred nonionic detergents, the alkyl groups present therein are preferably linear although a small degree of slight modification can be tolerated, for example on a carbon contiguous or distant from two carbons of the terminal carbon atom of the right chain and far from the ethoxy chain, provided that this branched alkyl is not more than three carbons in length.

   Normally, the proportion of carbon atoms in such a configuration

  <Desc / Clms Page number 12>

 branched must be weak and rarely exceed 20% of the total carbon content of the alkyl. Similarly, although linear alkyls terminally joined to the ethylene oxide chains are very preferred and are considered whether they produce the optimal combination of detergency, biodegradability and non-gelling characteristics, there may be a median or secondary union to ethylene oxide in the chain.



  In this case, it generally exists only on a small proportion of these alkyls, generally less than 20%, but it can be higher as is the case of the aforementioned Tergitol. Also when propylene oxide is. present in the lower alkylene oxide chain, it generally constitutes less than 20% and preferably less than 10%.



   With the nonionic detergent, which is the main synthetic organic detergent of the liquid detergent compositions of the invention, an anionic detergent can be used. The anionic detergent compounds which are particularly preferred are the higher alkyl type salts.
 EMI12.1
 (10 to 18 or 20 carbon atoms) benzenesulfonate including. alkyl group preferably contains 10 to 15 carbon atoms and more preferably is a straight chain alkyl radical of 12 or 13 carbon atoms.

   Preferably, such an alkylbenzenesulfonate has a high content of 3- (or more) phenyl isomers and correspondingly a low content (generally much less than 50%) of 2- (or less) phenyl isomers; in other words, the benzene ring is preferably to a large extent attached to the 3,4, 5,6 or 7 position of the alkyl group and the content of the isomers in which the benzene ring is attached to the 1 or 2 position is correspondingly weak. Alkylbenzenesulfonates constituting typical surfactants are described in US Pat. No. 3,320,174. Of course, more highly branched, but generally alkylated, benzenesulfonates can be used.

  <Desc / Clms Page number 13>

 
 EMI13.1
 in reality they are not preferred because of their lack of biodegradability.



   Other anionic detergents which are useful are the olefin sulfonate type salts. Generally, they contain long chain alkenylsulfonates or long chain hydroxyalkanesulfonates (the hydroxy of which is on a carbon atom which is not directly attached to the carbon atom carrying the SOH group). The olefinesulfonate type detergent generally consists of a mixture of such compounds in variable amounts often with disulfonates or long chain sulfate sulfonates. Such olefinesulfonates are described in numerous patents such as US Patents 2,061,618, 3,409,637.3 332,880.3 420,875.3 428,654 and 3,506,580 and British Patent 1,129,158.

   The olefinesulfonate generally has a number of carbon atoms in the range from 10 to 25, more generally from 10 to 18 or 20, and for example consisting of mixtures mainly of C12, C14 and C16 having on average about 14 carbon atoms or a mixture mainly of C, C, g and C18 having on average about 16 carbon atoms.



   Another category of useful anionic detergents is that of higher paraffinsulfonates. They may be primary paraffinsulfonates prepared by reaction of long chain α-olefins and bisulfites, for example sodium bisulfite, or paraffinesulfonates whose sulfonate groups are distributed along the paraffin chain such as the prepared products by reacting a long chain paraffin with sulfur dioxide and oxygen in the presence of ultraviolet light and then neutralizing with sodium hydroxide or another suitable base (as in US Patents 2,503,280.2,507 088, 3,260,741 and 3,372,188 and German patent 735,096)

  . Paraffinsulfonates preferably contain from 13 to 17 carbon atoms and are normally monosulfonates

  <Desc / Clms Page number 14>

 but if desired, they can be di- or trisuifonates or higher polysulfonates. Typically, the di- and polysulfonates are used in admixture with a corresponding monosulfonate, for example in the form of a mixture of mono- and disulfonates containing up to about 30% of the disulfonate. Their hydrocarbon substituent is preferably linear, but if desired branched paraffinsulfonates can be used although they are not as good as regards biodegradability.



   Other suitable anionic detergents are the ethoxylated sulfated higher fatty alcohols of formula RO (C2H40) mSO3M, in which R is a fatty alkyl of 10 to 18 or 20 carbon atoms, my having a value of 2 to 6 or 8 (preferably a value of about 1/5 to 1/2 of the number of carbon atoms in R) and M is a solubilizing salifying cation, such as an alkali metal, ammonium, lower alkylamino or lower alkanolamino, or alkylbenzenesulfonate higher including alkyl higher than 10 to 15 carbon atoms.

   As in the case of the preferred nonionic detergent, it is preferred that the alkyl of the detergent consisting of an anionic alkoxylate is a mixture comprising different chain lengths such as chains of 11, 12, 13, 14 and 15 carbon atoms or chains of 12 and 13 carbon atoms rather than a compound having only one chain length.



   Ethylene oxide is the preferred lower alkylene oxide of the detergent consisting of an anionic alkoxylate as is the case for the nonionic detergent and its proportions in the polyethoxylated higher alkanolsulfate are preferably from 2 to 5 moles of ethylene oxide group per mole of anionic detergent, three moles being particularly preferred in particular when the lower alkanol has 11 or 12 to 15 carbon atoms.

   To maintain the desired hydrophilic-lipophilic balance, when the carbon atom content of the alkyl chain is in the lower portion

  <Desc / Clms Page number 15>

 from the range of 10 to 18 carbon atoms, the ethylene oxide content of the detergent can be reduced to about 2 moles per month while when the lower alkanol has 16 to 18 carbon atoms, which is in the range In the upper part of the range, the number of ethylene oxide groups can be increased to 4 or 5 and in certain cases reach 8 or 9. Similarly, the salt-forming cation can be modified so as to obtain the best solubility. It can be any suitable metal or solubilizing radical, but an alkali metal, for example sodium or ammonium, is very particularly preferred.

   If lower alkyl or alkanolamine groups are used, the alkyls and alkanols generally contain from 1 to 4 carbon atoms and the amines and alkanolamines can be mono-, di- and tri-substituted as in the case of monoethanolamine, diisopropanolamine and trimethylamine.



   Polyalkoxy (lower) alkanol (upper) sulfates can be used in place of other preferred detergents such as higher alkylbenzenesulfonates or in combination with them to supplement the nonionic detergent in
 EMI15.1
 the liquid detergent compositions of the invention. A die- . Preferred polyethoxylated alcohol sulfate type tergent is supplied by Shell Chemical Company and marketed as Neodol 25-3S.



   Examples of the polyethoxylated higher alcohol sulfates which can be used in the liquid detergent compositions of the invention include: the sodium salt of a triethoxylated alkyl sulfate having radicals
 EMI15.2
 normal or primary mixed C-C alkyls. the potassium salt of triethoxylated myristyl sulfate i the diethanolamine salt of diethoxylated n-decyl sulfate i the ammonium salt of diethoxylated lauryl sulfate; the sodium salt of tetraethoxylated palmitylsulfate, i the salt; sodium trietetethethoxylated tri sulfate with normal mixed C alkyl polymer radicals, <. e? the trimethylamine salt of stearyl sulfate penta-

  <Desc / Clms Page number 16>

 
 EMI16.1
 ethoxylated;

   and the potassium salt of triethoxylated alkyl sulfate. with primary normal mixed alkyl radicals in C.-p.



   Other useful anionic detergents include higher acylsarcosinates, for example sodium N-lauroylsarcosinate; higher fatty alcohol sulfates such as sodium lauryl sulfate and sodium sulfide alcohol; sulfated oils; sulfates of mono or diglycerides of higher fatty acids, for example stearic monoglyceride monosulfate; although among them the higher sodium alcohol sulfates were found to be lower than the polyethoxylated sulfates by detergency;

   aromatic poly (lower alkenyloxy) ethersulphates, such as the sulphates of the condensation products of ethylene oxide and nonylphenol (generally having 10 to 20 oxyethylene groups per molecule, preferably 2 to 12), higher polyethoxyalcohols and polyethoxyalkylphenolsulfates having a substituent to lower coxy (from 1 to 4 carbon atoms, for example a methoxy) on a carbon close to that carrying the sulfate group, such as a monomethyl ether monosulfate of a
 EMI16.2
 long chain vicinal glycol, for example a mixture, of vicinal alkanediols having 16 to 20 carbon atoms in a straight chain; acyl esters of isethionic acid, for example oleyl isethionates;

   N-methyl-
 EMI16.3
 acyltaurides, for example potassium N-methyllauroyl- or oleyltaurides; higher alkylphenylpolyethoxysulfonates; higher alkylphenyldisulfonates, for example pentadecyl phenyldisulfonate; and higher fatty acid soaps, for example mixed soaps of coconut oil and tallow in a ratio of 1/4.



   Among the aforementioned types of anionic detergents, sulfates and sulfonates are generally preferred, but the corresponding organic phosphates and phosphonates can also be used when their phosphorus contents are not undesirable. Generally, organic detergents

  <Desc / Clms Page number 17>

 anionic water-soluble synthetic nicks (including soaps) as previously indicated, are alkali metal cation salts such as potassium, lithium and especially sodium, although ammonium cation salts can also be used and substituted ammonium such as those previously described, for example triethanolamine and triisopropylamine.

   In the above examples of anionic water-soluble detergents, it should be considered that the sodium, potassium, ammonium and alkanolammonium salts are each listed for each detergent.



   Ampholytic detergents can be. used in the compositions of the invention in small proportions to replace the anionic detergent or a part thereof or to replace a part of the nonionic detergent. Ampholytic detergents include higher carboxylates, phosphates, sulfates or sulfonates, which contain a cationic substituent such as an amino group, which may be quaternized, for example with a lower alkyl group or whose chain may be extended on the amino group by condensation a lower alkylene oxide, for example ethylene oxide. Generally, compositions containing such ampholytic or cationic detergents are not as effective and may be more likely to gel or thicken on standing.

   So we often avoid them. However, if such properties are not troublesome, small amounts of ampholytic agents can be used such as Miranol C2M sold by Miranol Chemical Company, or Deriphat 151, which is a sodium N-coco ss-aminepropionate, sold by General Mills, Inc. A cationic detergent that can sometimes be useful is distearyldimethylammonium chloride (which has fabric softening activity) and higher fatty amine oxides such as bis (2-hydroxyethyl) oxide octadecylamine.

  <Desc / Clms Page number 18>

 



   The viscosity adjusting agent used to maintain the desired viscosity of the liquid detergent composition, avoid gelation at low temperatures and allow a decrease in the content of solvent consisting of a lower alkanol, is preferably a formate soluble in the water. Sodium formate is preferred, but alkali metal formates can be used, for example potassium formate and various other water-soluble formates including formic acid which can be added to the liquid detergent composition in which it dissolves, ionizes and / or reacts to produce essentially the same type of liquid detergent as that which results from the addition of the alkali metal formate in the form of a salt.

   Other formates which can be used are those of water-soluble cations, such as those previously described as salifying cations for anionic detergents. Although it is preferred to use a formate as a viscosity adjusting agent, it has been found that various diacid salts can also be used with success, of which the best appear to be disodium adipate which is referred to herein as sodium adipate. sodium. Other diacid salts of formula (CH) (COOH) in which there is a value from 1 to 6, can also be used and in some cases the salts of monounsaturated acids with the same chain length and the same configuration can be used.



  However, it is much preferred to use the saturated straight aliphatic chain compounds with terminal carboxylation.



    We especially prefer to use those in which n has a value of 3 to 5 and better of 4 and the acid is. fully neutralized, but acid salts can also be used.



   Among the diacids which can be used either in the form of monosalts or disels, are malonic, succinic, glutaric, adipic and pimelic acids.



  An unsaturated diacid, maleic acid, can also be

  <Desc / Clms Page number 19>

 used at least partially. The acids can be used without prior neutralization or can be used in the form of their salts such as disodium malonate, monopotassium succinate, di-triethanolamine glutarate, disodium adipate and monosodium pimelate.



   To promote the solubilization of detergents and optical brighteners which may be present in liquid detergent compositions, a small proportion of an alkaline material or a mixture of such materials is often incorporated into the composition of the invention. Suitable alkaline materials include mono-, di- and trialkanolamines, alkylamines and ammonium hydroxide.



  Among these materials, alkanolamines are preferred and better still trialkanolamines and more particularly triethanolamine. The pH of the final liquid detergent composition containing such a basic material is generally neutral or slightly basic. Satisfactory pH ranges are between 7 and 10, preferably between about 7.5 and 9 and more preferably between about 7.5 and 8.5.



   Optical brightening agents or
 EMI19.1
 brightener used in liquid detergent compositions. are important constituents of modern detergent compositions which give linen and washed articles a shiny appearance so that the linen is not only clean but also appears clean. Although it is possible to use a single brightener for a particular use in the liquid detergent of the invention, it is generally desirable to use mixtures of brighteners having good brightening effects on cotton, nylons , polyesters and mixtures of these materials and which are also stable to bleaching. A good description of these types of optical brighteners is given in the article "The Requirements of Present Day Detergent Fluorescent Whitening Agents" by A. E. Siegrist, J. Am.

   Oil Chemists Soc., January 1978 (vol. 55). This article and US Patent 3,812,041 con-

  <Desc / Clms Page number 20>

 hold detailed descriptions of a wide variety of suitable optical brighteners.



   Among the whitening agents which are useful in the liquid detergent compositions of the invention are: Calcofluor 5BM (American Cyanamid); Calcofluor White ALF (American Cyanamid); SOF A-2001 (Ciba); CDW (Hilton-Davis); Phorwite RKH, Phorwite BBH and Phorwite BHC (Verona); CSL, powder, acid (American Cyanamid); FB 766 (Verona); Blancophor PD (Gaf) UNPA (Geigy); and the Tinopal RBS 200 (Geigy). The acidic or "nonionic" forms of the brighteners tend to be dissolved by the alcohols of the compositions of the invention while the salts tend to be soluble in water.



   Adjuvants can be present in the liquid detergent composition to give it additional functional or aesthetic properties. Among the useful adjuvants are soil suspending or anti-deposition agents such as polyvinyl alcohol, sodium carboxymethylcellulose, hydroxypropylmethylcellulose; thickeners, for example gums, alginates, agar-agar; foam improvers, for example lauric-myristic diethanolamide; defoamers, for example silicones; bactericides, for example tribromosalicylanilide, hexachlorophene dyes; pigments (dispersible in water); conservatives   ; ultraviolet absorbents; fabric softeners;

   opacifying agents, for example polystyrene suspensions; and perfumes.



  We must of course. choose these materials according to the desired properties of the finished product and they must be compatible with the other constituents of the product. Other adjuvants which can be used are the lower di- or tri-alcohols which, in addition to their solvent nature and the lowering of the flash point of the product which they cause, can behave as anti-freeze constituents and

  <Desc / Clms Page number 21>

 can improve the compatibility of the solvent system with the particulate components of the product.

   Among these compounds, the particularly preferred group consists of lower polyols having 2 to 3 carbon atoms, for example ethylene glycol, propylene glycol and glycerol, but the derivatives of lower alkyl ether type (Cl-C4) of these known compounds under the name of Cellosolve can also be used. The proportions of these agents replacing the lower alkanols are limited and normally do not exceed more than 20% of the total alcohol content of the liquid detergent.



   Another category of useful additives are hydrotropes which serve to increase the solubility in the aqueous solution of components which otherwise have limited solubility in water. Useful hydrotropes are the alkali metal salts of ammonium and ethanolamine of the following acids: (1) arylsulfonic acids such as benzenesulfonic acid and benzenesulfonic acids substituted with C1-C3 alkyl, for example acid toluenesulfonic and xylenesulfonic acid; and (2) C5-C6 alkylsulfuric acids such as hexylsulfuric acid.



   The proportions of the various components of the liquid detergent compositions of the invention are important for the manufacture of a uniform product of desirable viscosity and of acceptable acceptable whitening effect, not gelling at low temperature or by standing in a container open to the ordinary temperature.



   To increase the solubility of fluorescent whitening agents and other constituents in the detergent composition and to obtain a clear liquid product which is homogeneous and easy to pour, approximately 10 to 60% of the total liquid detergent concentrate must consist of detergents non-ionic. Preferably, in particular when an anionic detergent is present in the liquid product, the proportion of the nonionic detergent is from 20 to

  <Desc / Clms Page number 22>

 40% and better from 30 to 40%, the best composition currently known comprising around 32%. The proportion of the anionic detergent is generally in the range from 3 to 15%, preferably from 4 to 12% and better still from 6 to 10%, the best composition currently known containing about 7% thereof.

   The ratio of the totality of the nonionic detergent to the anionic detergent is normally from 15/1 to 1/1, better still from 8/1 to 2/1 and more particularly from 5/1 to 3/1.



   The lower alkanol in liquid detergent compositions is generally present in an amount sufficient to facilitate the dissolution and / or stabilization of the various constituents in the final product. The proportions of the lower alkanol used are normally around 3 to 15%, preferably from 4 to 12% and better still from 4 to 8% and currently very particularly around 5%.



   The viscosity adjusting agent used or a mixture of such agents normally constitutes about 0.5% to 5% of the final liquid detergent composition, preferably about 0.5% to 3% and better still about 1%.



   The percentage of water which is the main solvent for the compositions of the invention is generally from about 25 to 85%, preferably from 35 to 65% and better still from about 40 to 55% of the weight of the liquid composition. The particularly preferred compositions contain about 45 to 50% water.



   The content of the alkaline additive such as triethanolamine in the liquid composition is generally about 0.1% to 5% of the composition and preferably 1 to 3% by weight. The total proportion of the optical brightener is normally about 0.05 to 1.5%, preferably about 0 to 1% and better still about 0.2 to 0.5%.



   The liquid detergent compositions of the invention can be prepared according to simple manufacturing techniques. In a typical manufacturing process, the optical brighteners are suspended in the mono-

  <Desc / Clms Page number 23>

 alcohol then water is added to the suspension with a small amount of a base such as triethanolamine helping to partially dissolve the material previously in suspension. The addition of the anionic detergent compound generally causes the remainder of the brightener to dissolve with the formation of a clear solution. The viscosity adjusting agent is then added in the form of the acid, acid salt or fully neutralized salt, preferably sodium or potassium salt and stirring is continued until the solution clears up, which takes about 5-10 minutes.

   At this point, the main detergent, the non-ionic detergent, is added with a small amount of acid for pH adjustment, the pH generally being adjusted to a value at which the proteolytic enzyme used is most stable. This is followed by agitation of the solution and the addition of adjuvants, such as perfume and dye, which impart the desired final properties to the product. The protease and α-amylase enzyme preparations are then added to the solution and mixed as a final step to produce the liquid detergent composition. If desired, the viscosity adjustment additive can be incorporated earlier in the operation.



   The above operations can be carried out at room temperature although suitable temperatures in the range of 20 to 500C can be used if desired provided that when volatile materials such as perfume are added, the temperature should be low enough not to cause unacceptable losses. The product obtained generally has a pH in the range of 7 to 10 and a density in the range of 0.9 to 1.1, preferably 0.95 to 1.05. The viscosity of the final product at 24 ° C. is in the range from 60 to 150 centipoise, preferably from approximately 80 to 140 centipoise and better still from approximately 115 to 135 centipoise,

  <Desc / Clms Page number 24>

 the measurement being carried out with a Brookfield viscometer at ordinary temperature.



   The liquid compositions of the invention are effective and easy to use. Compared to powerful detergent washing powders, much smaller volumes of the liquids of the invention are used to obtain comparable cleaning of dirty laundry. For example, when using a typical preferred composition of the invention, about 60 g or a quarter of a cup of liquid is sufficient for a full wash tub in an automatic top-loading washing machine containing 55 to 75 liters of water. Even less water (about half) is enough for side loading machines.



  Therefore the concentration of the liquid detergent composition in the washing water is of the order of about 0.1%. Generally, the proportion of the liquid composition in the washing solution is in the range of about 0.05 to 0.3%, preferably 0.08 to 0.2% and more preferably about 0.1 to 0.15%. The proportions of the various constituents of the liquid composition vary correspondingly.
 EMI24.1
 



  Equivalent results can be obtained by using. increased proportions of a more dilute composition but the larger quantity required requires larger containers and generally less practical for the user. Also, more highly diluted products tend to freeze in cold weather and may be more sensitive to hydrolysis and chemical variations during storage.



   The invention is illustrated by the following nonlimiting examples.



    Example 1.



   A liquid detergent composition (not containing an enzyme) called composition "A" is prepared at ordinary temperature by mixing the following components in the proportions indicated:

  <Desc / Clms Page number 25>

   Components% by weight Primary alcohol in C -C ethoxylated (7 moles of EO / mole of alcohol) 32.0 Sodium dodecylbenzenesulfonate 7.0 Triethanolamine 2.8 Ethanol 5.0 Sodium formate 1.0
 EMI25.1
 H2S04 (concentrated) 0, 7 Optical brighteners 0, 27 Colorant 01 Fragrance 0, 35 Complement water (1) A mixture of the brighteners Phorwite RKH and Phorwite BHC manufactured by Verona.



  (2) Polar Brillant Blue (PBB) manufactured by Ciba-Geigy.



   Liquid detergent compositions containing B-U enzymes are prepared by adding various amounts of protease and α-amylase enzymes to composition A described
 EMI25.2
 above. The concentration of the enzymes in each of the detergent compositions is shown in Table 1 where it is expressed as a percentage of enzymatic preparation relative to the weight of the composition. protease used is a liquid enzyme composition sold under the name "Alcalase" by Novo Industries of Copenhagen, Denmark, having a concentration of 2.5 Anson units per gram of enzyme preparation. The enzyme α-amylase used is a liquid enzymatic preparation sold under the name of "Termamyl" by Novo Industries having a concentration of 120,000 units of Novo amylase per gram of liquid enzymatic preparation.



  Test protocol.



     A total of 6 cotton coupons, 3 stained with beef liver blood and 3 grass stains are placed in each of 4 tubs of a Tergotometer container made by the U. S. Testing Company. We perform a series of tests

  <Desc / Clms Page number 26>

 of washing with a different liquid detergent composition consisting of compositions A to U in each tub of the Tergotometer under the following test conditions: Concentration of liquid detergent 0.09% Agitation 100 rpm Agitation time 10 minutes Temperature of the water 490C Water hardness around 150 ppm calcium carbonate
At the end of the washing, the test coupons are rinsed in tap water and then dried.

   The percentage of stain removal is measured by determining the reflection factors of each stained test coupon before and after washing with a Gardner XL-20 colorimeter and the percentage of stain removal (% SD) is calculated as follows :
 EMI26.1
 (value after washing) - (value before washing) (value before formation- (value before washing) of stains) in which "value before washing" is the value after formation of stains.



   The values of the stain removal percentages calculated for each of the three test coupons bearing the same type of stain are established for each liquid detergent composition studied. The results appear in the table which shows the stain removal percentages for each of the liquid detergent compositions studied (compositions A-U) and the enzymatic concentration of these detergent compositions.

   -

  <Desc / Clms Page number 27>

 
TABLE Comparative elimination of stains with detergent compositions containing enzymes
 EMI27.1
 
 <tb>
 <tb> Compo-% <SEP> in <SEP> weight <SEP>% <SEP> in <SEP> weight <SEP> of% <SEP> elimination <SEP> of
 <tb> sition <SEP> from <SEP> protease <SEP> a-amylase <SEP> (2) <SEP> stains <SEP>
 <tb> Blood <SEP> from <SEP> liver <SEP> Grass
 <tb> of <SEP> beef
 <tb> A <SEP> 0, <SEP> 0 <SEP> 0.0 <SEP> 42.0 <SEP> 31.5
 <tb> B <SEP> 0.2 <SEP> 0.0 <SEP> 50.8 <SEP> 37.6
 <tb> C <SEP> 0.4 <SEP> 0.0 <SEP> 52.8 <SEP> 36.7
 <tb> D <SEP> 0.6 <SEP> 0.0 <SEP> 53.9 <SEP> 36.8
 <tb> E <SEP> 0.8 <SEP> 0.0 <SEP> 55, <SEP> 5.

    <SEP> 36.1
 <tb> F <SEP> 0.0 <SEP> 0.2 <SEP> 44.2 <SEP> 37.6
 <tb> G <SEP> 0.2 <SEP> 0.2 <SEP> 55.3 <SEP> 42.4
 <tb> H <SEP> 0.4 <SEP> 0.2 <SEP> 58.4 <SEP> 44.8
 <tb> I <SEP> 0.6 <SEP> 0.2 <SEP> 60.6 <SEP> 44.5
 <tb> J <SEP> 0.8 <SEP> 0.2 <SEP> 60.5 <SEP> 44.1
 <tb> K <SEP> 0.0 <SEP> 0.4 <SEP> 47.1 <SEP> 38, <SEP> 3
 <tb> L <SEP> 0.2 <SEP> 0.4 <SEP> 56.2 <SEP> 43.4
 <tb> M <SEP> 0.4 <SEP> 0, <SEP> 4 <SEP> 58, <SEP> 6 <SEP> 45.0
 <tb> N <SEP> 0.6 <SEP> 0.4 <SEP> 63.3 <SEP> 44.8
 <tb> 0 <SEP> 0.8 <SEP> 0.4 <SEP> 63.2 <SEP> 45.0
 <tb> p <SEP> 0.0 <SEP> 0.6 <SEP> 47.7 <SEP> 37.6
 <tb> Q <SEP> 0.2 <SEP> 0.6 <SEP> 55.4 <SEP> 41, <SEP> 3 <SEP>
 <tb> R <SEP> 0, <SEP> 4 <SEP> 0.6 <SEP> 57, <SEP> 5 <SEP> 42.1
 <tb> S <SEP> 0, <SEP> 6 <SEP> 0.6 <SEP> 60.9 <SEP> 43, <SEP> 7- <SEP>
 <tb> T <SEP> 0.8 <SEP> 0.6 <SEP> 62.0 <SEP> 44.5
 <tb> U <SEP> 0.0 <SEP> 0.8 <SEP> 47, <SEP> 7 <SEP> 36, <SEP> 5
 <tb>
 (1)

   The proteolytic activity of Alcalase is 2.5 Anson units per gram. So a concentration for example of

  <Desc / Clms Page number 28>

 0.2% of Alcalase in the liquid detergent composition corresponds to an activity of the protease enzyme of 0.5 Anson unit (0.2 × 2.5) per 100 grams of detergent composition.



  (2) The amylolytic activity of Termamyl is 120,000 units of Novo amylase per gram. Therefore a concentration of 0.2% of Termamyl in the liquid detergent composition corresponds to an activity of the α-amylase enzyme of 24,000 units of Novo amylase (0.2 x 120,000) per 100 grams of detergent composition.



   As indicated in the table, the percentage of stain removal (E.T.) obtained with composition A represents E. T. obtained in the absence of enzyme in the detergent composition. Regarding the values of E. T. for beef liver blood stains, a comparison of the TEs obtained with compositions F, K, P and U which all contain the amylase enzyme but not the protease enzyme and which therefore do not conform to l The invention shows that composition P containing 0.6% by weight of α-amylase produces the maximum improvement in E. T.



  (47.7%) that can be obtained with the enzyme amylase, that is to say an increase of about 5.7% compared to the value of E. T. of 42.0% for composition A containing no enzyme. Similarly, a comparison of the TEs obtained with compositions B, C, D and E which all contain the protease enzyme but not the amylase enzyme, shows that composition E containing 0.8% protease produces the maximum improvement of the ET. (55.5%) with the protease enzyme, i.e. an increase in
 EMI28.1
 about 13.5% compared to E. T. of 42%. obtained with composition A containing no enzyme.



   The synergistic interaction of the protease and amylase enzymes in the removal of protein stains is evident from the table. Thus, for example, composition G containing 0.2% by weight of the protease enzyme and 0.2% by weight of the amylase enzyme (which corresponds to a

  <Desc / Clms Page number 29>

 amylase / protease enzyme activity ratio of 24,000 units of Novo amylase per 0.5 Anson unit) provides almost the same improvement in E. T. (relative to composition A containing no enzyme) than that obtained with 0.8% by weight of protease in composition E.

   From the economic point of view, the use of composition G containing a mixture of enzymes according to the invention ensures a significant reduction in the necessary quantity of the relatively expensive protease enzyme compared to composition E.



   The maximum percentage of stain removal is obtained with composition N. More particularly, the combination of 0.6% by weight of protease and 0.4% by weight of amylase in composition N provides an increase in the percentage of 'E. T. greater than 21% for blood stains compared to composition A without enzyme.



  So the. T. of 63.3% obtained with this composition N is much higher than E. T. maximum that could be obtained with detergent compositions containing the protease enzyme in the absence of α-amylase. The amylase / protease enzymatic activity ratio of this composition N is 48,000 units of Novo amylase per 1.5 Anson units.



   The synergistic interaction of the protease and α-amylase enzymes is evident from the E values. T. relating to grass stains. Thus, for example, composition E containing 0.2% of amylase enzyme and 0.4% of protease enzyme provides an ET significantly higher than that which could be obtained with detergent compositions containing either protease or amylase as individual enzymes in the composition.


    

Claims (13)

 CLAIMS 1. Liquid detergent composition containing enzymes comprising: (a) approximately 5 to approximately 75% by weight of one or more detergent surfactants chosen from anionic, nonionic, cationic, ampholytic and zwitterionic detergent compounds: (b ) approximately 25 to 85% of water: and (c) a mixture of enzymes essentially consisting of an alkaline protease and an α-amylase in relative proportions such that the ratio of the respective enzymatic activities in said mixture is d about 4,000 to about 80,000 units of Novo α-amylase amylase per Anson unit of the protease, said protease being present in an amount providing about 0.25 to about 2.5 Anson units per 100 grams of composition detergent.  2. A detergent composition according to claim 1, wherein the ratio of the enzymatic activities in said mixture of enzymes is from about 15,000 to about 40,000 units of Novo α-amylase amylase per Anson unit of protease and said protease is present in an amount providing from about 0.5 to about 2; 0 Anson units per 100 g of detergent composition.  3. A detergent composition according to claim 2, wherein said ratio of enzyme activities is from about 30,000 to about 40,000 units of Novo α-amylase amylase per Anson unit of protease.  4. A detergent composition according to claim 1, in which said detergent surfactants consist essentially of approximately 20% to approximately 40% by weight of a nonionic detergent consisting of an alkoxyl (C, QC. G) alkoxylé ( C -Cg) soluble in water and approximately 4 to 12% by weight of an anionic detergent consisting of a water-soluble salt of the alkyl o-Cj) - benzenesulfonate type: and which additionally contains approximately 3 to 15%  <Desc / Clms Page number 31>  by weight of a lower alkanol chosen from the group consisting of a lower monoalcohol having 1 to 4 carbon atoms, a lower polyol having 2 to 3 carbon atoms and their mixtures.  5. A detergent composition according to claim 1, which additionally contains about 0.5 to 5% by weight of a viscosity adjusting agent chosen from salts of the formate type soluble in. water and the diacids of formula (CH) (COOH) in which n has a value of 1 to 6.  6. Liquid detergent composition containing enzymes consisting essentially of: (a) approximately 20 to approximately 40% by weight of a nonionic detergent compound consisting essentially  EMI31.1  an alkanol (C. -C) soluble in water (b) about 4 to about 12% by weight of an anionic detergent compound essentially consisting of a salt soluble in water of the alkyl type (C. - C, E) benzenesulfonate; (c) about 3 to 15% by weight of a lower alkanol chosen from a lower monoalcohol having 1 to 4 carbon atoms, a lower polyol having 2 to 3 carbon atoms and their mixtures; (d) about 0.5% to 5% by weight of a viscosity adjusting agent consisting essentially of a water-soluble formate;  (e) about 35% to 65% by weight of water; and (f) a mixture of enzymes essentially consisting of an alkaline protease and an α-amylase in relative proportions such that the ratio of the respective enzymatic activities in said mixture is from approximately 4,000 to approximately 80,000 units of amylase Novo of α-amylase per Anson unit of protease, said protease being present in an amount providing approximately 0.25 to approximately 2.5 Anson units per 100 g of detergent composition.  7. A detergent composition according to claim 6, which contains more than 0.1 to 5% by weight of an alkanol-  <Desc / Clms Page number 32>  amine.  8. A detergent composition according to claim 6, wherein the ratio of enzyme activities in said mixture of enzymes is from about 15,000 to about 40,000 units of Novo α-amylase amylase per Anson unit of protease and said protease is present in an amount providing from about 0.5 to about 2.0 Anson units per 100 g of detergent composition.  9. A detergent composition according to claim 8, wherein said ratio of enzymatic activities is from about 30,000 to about 40,000 units of Novo α-amylase amylase per Anson unit of protease.  10. A detergent composition according to claim 6, wherein said non-ionic detergent compound is a (C -C) polyalkoxy alkanol having 3 to 12 ethylene oxide groups per mole; said anionic detergent is a  EMI32.1  (C12 or C13) alkyl benzenesulfonate; said lower alkanol is ethanol or a mixture of ethanol and isopropanol; and said viscosity adjusting agent is sodium formate.  11. A washing method comprising contacting stained and / or soiled washing clothes with a liquid detergent composition containing enzymes comprising: (a) approximately 5 to approximately 75% by weight of one or more selected detergent surfactants among the anionic, nonionic, cationic, ampholytic and zwitterionic detergent compounds; (b) about 25 to 85% water;  and (c) a mixture of enzymes essentially consisting of an alkaline protease and an α-amylase in relative proportions such that the ratio of the respective enzymatic activities in said mixture is approximately  EMI32.2  4,000 to about 80,000 units of Novo α-amylase amylase,. per Anson unit of protease, said protease being present in an amount providing about 0.25 to about 2.5 units  <Desc / Clms Page number 33>  Anson per 100 g of detergent composition.  The method of claim 11, wherein the ratio of enzyme activities in said mixture of enzymes is from about 15,000 to about 40,000 units of Novo α-amylase amylase per Anson unit of protease and said protease is present in an amount providing about 0.5 to about 2.0 Anson units per 100 g of detergent composition.  13. The method of claim 11, wherein said liquid detergent composition consists essentially of: (a) about 20 to about 40% by weight of fine nonionic detergent compound consisting essentially of an alkanol (C. -C. p. ) alkoxylated (C2-C3) soluble in water;  (b) about 4 to about 12% by weight of an anionic detergent compound consisting essentially of a water-soluble salt of the alkyl (C, -Cbenzenesulfonate) type; (c) about 3 to 15% by weight of a lower alkanol selected from the group consisting of a lower monoalcohol having 1 to 4 carbon atoms, a lower polyol having 2 to 3 carbon atoms and their mixtures; (d) about 0.5 to 5% by weight of an agent d adjustment of the viscosity consisting essentially of a water-soluble formate;  (e) about 35 to 65% by weight of water; and (f) a mixture of enzymes essentially consisting of an alkaline protease and an α-amylase in relative proportions such that the ratio of the respective enzymatic activities in said mixture is from approximately 4,000 to approximately 80,000 units d amylase Novo of α-amylase per Anson unit of protease, said protease being present in an amount providing approximately 0.25 to approximately 2.5 Anson units per 100 g of detergent composition.