GB2079305A - Liquid enzyme detergent - Google Patents

Abstract

Stable, aqueous, built liquid enzymatic detergent compositions can be obtained by the inclusion in an aqueous, built liquid enzymatic detergent composition of a mixture of a polyol and boric acid or an equivalent thereof in a weight ratio of polyol to boric acid more than 1, and a neutralised cross-linked polyacrylate polymer.

Description

SPECIFICATION Liquid enzymatic detergent composition The present invention relates to a stable, aqueous built liquid enzymatic detergent composition. Aqueous liquid enzymatic detergent compositions are well-known in the art. The major problem which is encountered with such compositions is that of ensuring a sufficient storage-stability of the enzymes in these compositions. There have already been various proposals for the inclusion of special stabilizing agents in such liquid enzymatic detergent compositions, especially unbuilt liquid enzymatic detergents.

In the case of built liquid enzymatic detergent compositions, however, there is not only the additional problem of the possible effect of the builder material on the enzymes, but also the effect of the builder material on the overall physical (storage) stability of the liquid composition.

It has already been proposed to use a mixture of a polyol and boric acid or an equivalent thereof in enzymatic liquid detergent compositions, whereby the ratio of the polyol to the boric acid is smaller than1. These mixtures are preferably used in unbuilt liquids.

It has been found that, for built liquids, this ratio should be greater than 1 if no special measures are taken to keep the pH of the composition constant, but that the presence of builder materials do cause a physical stability problem, in that the compositions tend to separate into different phases.

According to the invention it has now been found that stable, aqueous, built liquid enzymatic detergent compositions can be obtained by the inclusion in an aqueous, built liquid enzymatic detergent composition of a mixture of polyol and boric acid or an equivalent thereof in a weight ratio of more than 1, and a particular cross-linked polymer to be defined more fully hereafter. By using these three ingredients, a stable, aqueous built enzymatic liquid detergent composition can be obtained, which has a satisfactory enzyme stability, especially at a higher pH, as well as a satisfactory physical storage stability.

The invention will now be explained in more detail.

The polyols for use in the present invention contain only C-, H- and O-atoms. They are free from other (functional) substituting atoms such as N-, Sand the like. The polyols should contain at least 2 hydroxy groups and may contain even up to 6 hydroxy groups. Typical examples of polyols particularly suitable for use in the present invention are diols such as 1 2-propanediol, ethylene-glycol, erythritan, polyols such as glycerol, sorbitol, mannitol, glucose, fructose, lactose, etc.

In general, the polyol is present in an amount of at least 1, preferably at least 4% by weight of the final composition, up to 25% by weight. Preferably the amount ranges from 5-15% by weight of the final composition.

The boric acid or the boron-equivalent thereof, such as boric oxide, borax and other alkali metal borates capable of reacting with a polyol, such as sodium, ortho-, meta- and pyroborates, is used in an amount such that the weight ratio of the polyol to the boron compound is more than 1 (calculated on the basis of borax). This means that the boron compound is used in an amount that is smaller than the amount of the polyol. Generally the amount of the polyol varies from > 100-200%, and preferably from > 100-160% by weight of the boric acid or equivalent thereof (calculated on the basis of borax).

The cross-linked polymer to be used in the present invention is a water-soluble polymer of acrylic acid cross-linked with not more than 10% of a vinyl group-containing cross-linking agent. These crosslinked polymers are more fully described in French Patent Specification No. 1,159,560.

Especially suitable are the water-soluble polymers of acrylic acid, cross-linked with about 1% of a polyallyl ether of sucrose having an average of about 5.8 allyl groups for each sucrose molecule, the polymer having a molecular weight in excess of 1,000,000. Examples of such polymers are Carbopol 934,940 and 941. Carbopol is the Registered Trademark of B. F. Goodrich Co. Ltd., the manufacturers of these polymers. The preferred polymer is Carbopol 941. The cross-linked polymer is used in the present invention in an amount of 0.1-2.0, preferably 0.25-1.0 and especially preferably 0.4-0.8% by weight of the total composition. These cross-linked polymers are normally acidic, and it is essential that they are present in the final composition in a neutralized form.In this respect it has been found that this neutralization should preferably be carried out in situ; separately neutralized polymer (i.e. by first dispersing the acidic polymer in water and subsequently adding a suitable base) did not provide a fully satisfactory stable liquid composition. The neutralization in situ is carried out by adding the polymer to an aqueous medium which contains a suitable alkaline material in a sufficient amount to at least partially, and preferably fully neutralize the polymer. In this respect it has been found that borax is a particularly suitable alkaline material.

The aqueous liquid compositions in which the stabilizing systems of the invention are incorporated are aqueous, built, liquid enzymatic detergent compositions further comprising as essential ingredients enzymes, builders and active detergents.

The enzymes to be incorporated can be proteolytic, amylolytic and cellulolytic enzymes as well as mixtures thereof. They may be of any suitable origin, such as vegetable, animal, bacterial, fungal and yeast origin. However, their choice is governed by several factors such as pH acitivity and/or stability optima, thermostability, stability versus active detergents, builders and so on. In this respect bacterial or fungal enzymes are preferred, such as bacterial amylases and proteases, and fungal cellulases.

Although the liquid compositions of the present invention may have a near-neutral pH value, the present invention is of particular benefit for enzymatic liquid detergents with a pH of 7.5 or above, especially those incorporating bacterial proteases of which the pH-optima lie in the range between 8.0 and 11.0, but it is to be understood that enzymes with a somewhat lower or higher pH-optimum can still be used in the compositions of the invention, benefiting from it.

Suitable examples of proteases are the subtilisins which are obtained from particular strains of B. subtilis and B. licheniformis, such as the commercially available subtilisins Maxatase D (ex Gist-Brocades N.V., Delft, Holland) and Alcalaseg (ex Novo Industri A/S, Copenhagen, Denmark).

As stated above, the present invention is of particular benefit for enzymatic liquid detergents incorporating enzymes with pH-acitivity andlor stability of above 8.0, such as enzymes also commonly called high-aikaline enzymes.

Particularly suitable is a protease, obtained from a strain of Bacillus, having maximum activity throughou the pH-range of 8-12, developed and sold by Novo Industri AyS under the registrated trade name Esperases. The preparation of this enzyme and analogous enzymes is described in British Patent Specification No. 1,243,784 of Novo.

High-alkaline amylases and cellulase can also be used, e.g. amylases obtained from a special strain of B. licheniformis, described in more detail in British Patent Specification No. 1,296,839 (Novo).

The enzymes can be incorporated in any suitable form, e.g. as a granulate (marumes, prills etc.), or as a liquid concentrate. The granulate form has often advantages.

The amount of enzymes present in the liquid composition may vary from 0.001 to 10% by weight, and preferably from 0.01 to 5% by weight.

The liquid detergent compositions of the invention furthermore comprise as essential ingredient an acitve detergent material, which may be an alkali metal or aikanol amine soap of C10C24 fatty acid, including polymerized fatty acids or an anionic, nonionic, cationic, zwitterionic or amphoteric synthetic detergent material, or mixtures of any of these.

Examples of anionic synthetic detergents are salts (including sodium, potassium, ammonium, and substituted ammonium salts such as mono-, di- and triethanolamine salts) of Cg-C20 alkylbenzenesulphonates, Ca-Cz primary or secondary alkanesulphonates, Ca-C24 olefinsulphonates, sulphonated polycarboxylic acids, prepared by sulphonation of the pyrolyzed product of alkaline earth metal citrates, e.g. as described in British Patent Specification No. 1,082,179, C8-C22 alkylsulphates, C8-C24 alkylpolyglycolethersulphonates (containing up to 10 moles of ethylene oxides); further examples are described in "Surface Active Agents and Detergents" (Vol. I and II) by Schwartz, Perry and Berch.

Examples of nonionic synthetic detergents are the condensation products of ethylene oxide, propylene oxide and/or butyleneoxide with C8-C15 alkyiphenols, C8-C,8 primary or secondary aliphatic alcohols, Cs-C18 fatty acid amides; further examples of nonionics include tertiary amine oxides with one C8-C18 alkyl chain and two C13 alkyl chains. The above reference also describes further examples of nonionics.

The average number of moles of ethylene oxide and/or propylene oxide present in the above nonion ics varies from 1-30; mixtures of various nonionics, including mixtures of nonionics with a lower and a higher degree of alkoxylation, may also be used.

Examples of cationic detergents are the quaternary ammonium compounds such as alkyldimethylammonium halogenides, but such cationics are less preferred for inclusion in enzymatic detergent compositions.

Examples of amphoteric or zwitterionic detergents are N-alkylamino acids, sulphobetaines, condensation products of fatty acids with protein hydrolysates but owing to their relatively high costs they are usually used in combination with anionic or a nonionic detergent. Mixtures of the various types of active detergents may also be used, and preference is given to mixtures of an anionic and a nonionic detergent active. Soaps (in the form of their sodium, potassium, and substituted ammonium salts such as of polymerized fatty acids, may also be used, preferably in conjuction with an anionic and/or a nonionic synthetic detergent.

The amount of the active detergent material varies from 1 to 60%, preferably from 2-40 and especially preferably from 5-25%; when mixtures of e.g. anionics and nonionics are used, the relative weight ratio varies from 10:1 to 1:10, preferably from 6:1 to 1:6.

When a soap is also incorporated, the amount thereof is from 140% by weight.

The liquid compositions of the invention further contain up to 60% of a suitable builder, such as sodium, potassium and ammonium or substituted ammonium pyro- and tripolyphosphates, -ethylenediamine tetraacetates, -nitrilotriacetates, -etherpolycarboxylates, -citrates, -carbonates, -orthophosphates, zeolites, carboxymethyloxysuccinate, etc. Particularly preferred are the polyphosphate builder salts, nitrilotriacetates, zeolites, and mixtures thereof. In general the builders are present in an amount of 1-60, preferably 5-50% by weight of the final composition.

The amount of water present in the detergent compositions of the invention varies from 5 to 70% by weight.

Other conventional materials may also be present in the liquid detergent compositions of the invention, for example soil-suspending agents, hydrotropes, corrosion inhibitors, dyes, perfumes, silicates, optical brighteners, suds boosters, suds depressants such as silicones, germicides, anti-tarnishing agents, opacifiers, fabric softening agents, oxygen-liberating bleaches such as hydrogen peroxide, sodium perborate or percarbonate, diperisophthalic anhydride, with or without bleach precursors, reducing bleaches such as sodium sulphite, buffers and the like.

The pH of the final compostions is near neutral, preferably higher than 7.5 and should preferably lie within the range of 8.0 to 10.0, and is, if necessary, buffered to a value within that range by addition of a suitable buffer system. The pH of the wash liquor, when using the composition, is about 1 pH unit higher than the above values at an in-use concentra tion of about 1%.

The invention will now be further illustrated by way of Example. In the Examples the percentages are by weight. In all the Examples the polymerwas added in an acidic form to the aqueous medium from which the liquid detergent composition was obtained, said medium already containing a sufficient amount of a suitable alkaline material for neutralization of the polymer.

Example I The following composition was prepared: potassium dodecylbenzene sulphonate 10 C13-C15 linear primary alcohol, condensed with 7 moles of ethyleneoxide 5 sodium tripolyphosphate 20 borax 10 glycerol 15 Carbopol 941 0.65 enzyme (Maxatases in the form of slurry) 0.3 fluorescer and perfume 0.25 water to 100.0 The pH of this product was 8.0-8.5; the pH rose to 9.0-9.5 at an in-use concentration of about 1%. The physical storage stability after storing for more than 1 month at room temperature and at 37"C was quite acceptable for practical purposes.The enzyme stability after storing for 1 month at room temperature and at 37"C was abt. 80% (residual activity), respectively 90% (residual activity), and the breakdown of the sodium tripolyphosphate was 15%, respectively 0-5% under these conditions.

Example 2 The following compositions were prepared: a b c d e f g sodium dodecylbenzene suiphonate - - - - 7.5 5 5 C13-C1s linear prim. alcohol, condensed with 7 moles of alkylene oxide (a mixture of ethylene- and propylene oxideinaweightratioof92::8) 10 10 10 10 2.5 5 5 an hydrous sodium tripolyphosphate 20 20 20 20 20 20 20 sorbitol - - - - - - 6 glycerol - 10 20 10 10 10 borax 7 7 7 7 7 7 7 Na20.3.3SiO2 - - - 2.7 - - Carbopol 941 0.8 0.8 0.8 0.8 0.65 0.7 0.7 enzyme (Alcalase or Esperase) * water balance pH 8.5 7.4 6.7 7.7 7.5 7.5 7.5 half-life time of enzymes (in days) at37"C Alcalase 2 55 80 50 100 90 12 Esperase 3 55 140 60 10 40 4 * The enzyme was added in such an amount that the final product had a proteolytic activity of 8.5 GU/mg (733 GU/mg = 1 Anson Unitlg) The compositions were stable for several months at room temperature.

Example 3 The following composition was prepared: wt.% sodium dodecylbenzene sulphonate 6 C1rCrs linear prim. alcohol condensed with 9 moles of ethylene oxide 3 sodium oleate 1 sodium citrate 2.aq 7 zeolite (type 4A) 28 sodium carboxymethylcellulose 0.5 borax 7.5 Carbopol 941 0.2 fluorescer 0.1 glycerol 7.5 or 10 water balance enzyme (Alcalase) (as in Example 2) These liquids were physically stable; the half-life time at 37"C of the enzymes was 10 days with 7.5% glycerol and 11 days with 10% glycerol.

Example 4 The following composition was prepared: vvt.% sodium dodecylbenzene sulphonate 5 C13-C1s linear prim. alcohol condensed with 7 moles of alkylene oxide (a mixture of ethylene- and propylene oxide in a weight ratio of 92:8) 2 anhydrous sodium tripolyphosphate 20 glycerol 10 borax 7 sodium sulphite 5 sodium carboxymethylcellulose 0.4 fluorescer 0.1 Carbopol 941 0.5 Alcalase (1163 glycine units/mg) 0.7 silicon oil 0.25 water balance The enzyme had a half-lifetime of 4 months at 37"C, and the product was physically stable still after 2 months at 3, 23, 37 and 52"C.

Claims (3)

1. An aqueous, built, liquid enzymatic detergent composition comprising enzymes, builders and detergent active materials in an aqueous medium, characterized in that the liquid composition contains a polyol, boric acid or a boron-equivalent thereof in a weight ratio of polyol to the boric acid of more than 1, as well as a neutralized cross-linked polyacrylate polymer.

2. A composition according to claim 1, characterized in thatthe polyol is glycerol, the boronequivalent is borax, and the cross-linked polymer is a polyacrylate, cross-linked with about 1% of a polyallyl ether of sucrose with about 5.8 allyl groups for each sucrose molecule, the polymer having a molecular weight in excess of 1.000.000.

3. A composition according to claim 1 or 2, characterized in that it contains from 1-25% by weight of the polyol and from 0.1-2% by weight of the cross-linked polymer.

4 A composition according to any one of claims 1-3, characterized in that it contains the cross-linked polymer in an in-situ neutralized form