NL8703029A - AQUEOUS LIQUID DISHWASHING COMPOSITION CONTAINING A STABILIZED ENZYME SYSTEM. - Google Patents

Description

9 i VO 9455 -1-

Aqueous liquid dishwashing composition containing a stabilized enzyme system.

The invention relates to aqueous built-up dishwashing compositions containing a stabilized enzyme system. The stabilized enzyme system contains a boron compound, an α-hydroxycarboxylic acid, casein and an enzyme. The invention particularly relates to aqueous liquid thixotropic clay-containing dishwashing compositions containing a stabilized enzyme system comprising a boron compound, eg sodium borax, an α-hydroxycarboxylic acid, eg lactic acid, tartaric or citric acid, casein and an enzyme such as a proteolytic or amylolytic enzyme. The invention particularly relates to detergent compositions for automatic dishwashers, which compositions contain a stabilized enzyme system with enzyme stability and physical stability and are readily dispersible in the washing medium for effective cleaning of dishes, glassware, china and the like.

The currently available powdered dishwashing detergent compositions and aqueous dishwashing detergent compositions, including thixotropic dishwashing compositions, do not contain stabilized enzyme systems.

The invention relates to built-up enzyme-containing aqueous liquid detergent compositions for use in dishwashers and suitable for cleaning crockery, glassware, china, kitchen utensils and the like.

In particular, the invention relates to aqueous, enzyme-containing liquid dishwashing detergent compositions which contain one or more detergent builder salts and are stable.

The automatic dishwashing compositions, further also referred to as AVD, generally contain (1) sodium tripolyphosphate for softening or binding minerals in hard water and for emulsifying and / or pepping dirt, (2) sodium silicate to provide the alkalinity necessary for effective detergent, and to provide protection for the glaze and pattern of fine china, (3) sodium carbonate, which is generally considered an optional component, to enhance alkalinity, ( 4) a chlorine-releasing

Mn V-n '»r *,. 4 i - ·.

r s · - v? L. - -2- agent to help eliminate speckles of dirt, which lead to water stains, and colored dirt, such as tea and coffee, and (5) antifoam / surfactant to reduce foaming, increasing machine efficiency is improved, and to provide required detergent. For example, reference is made to SDA Detergents in Depth, "Formulations Aspects of Machine Dishwashing", Thomas Oberle (1974). Cleansers with approximately the above-described compositions are usually liquids or powders.

However, the use of a chlorine releasing agent causes problems in some dishwashing compositions because the chlorine releasing agent can react with other chemically active ingredients, in particular surfactants (see U.S. Patent 4,115,308), affecting the suspending agent or thixotropic agent and impairing its effectiveness.

It is an aspect of the invention that a chlorine releasing agent is not needed in the composition of the invention.

The composition of stabilized enzyme-containing liquid dishwashing compositions has presented difficult problems. Indeed, the desirability of including enzymes in dishwashing detergent compostions arises from the effectiveness of proteolytic and amylolytic enzymes for decomposing proteinaceous and starchy materials found on soiled crockery and the like, thereby removing residual food materials such as salt, egg, tomato salt, chocolate and the like is facilitated during washing in an automatic dishwasher. However, enzymatic materials suitable for dishwashing compositions, especially proteolytic enzymes, are relatively expensive. In addition, enzymes are known to be unstable in aqueous built-up laundry detergent compositions.

It is known that in the case of liquid laundry detergent compositions containing a phosphate builder salt, the problem of enzyme instability is particularly acute, mainly because phosphate detergent builder salts on enzymes have a destabilizing effect. In addition, the inclusion of a phosphate builder salt in a liquid dishwashing detergent composition causes a further problem, namely, the ability to form a stable single-phase composition; For example, the solubility of sodium tripolyphosphate in aqueous compositions is relatively limited, especially in the presence of anionic detergents.

Also in high alkalinity detergent compositions, enzymes are also difficult to stabilize because high acalinity is known to deactivate enzymes. While it is possible to lower the pH to improve the stability of enzymes, it does harm the beneficial effect of the build-up salts to some extent. The stabilized enzyme system of the invention provides enzyme-10 stability even at relatively high pH, such as a pH of 10-12.

Such high pH values of, for example, 10-12 give better detergent and are therefore preferred. Lowering the pH of the detergent composition, for example to a value of 7.5-9.5, may increase the stability of the enzyme, but decrease the life of the suds foam, as well as the beneficial effect of the build-up salt, especially the detergent .

U.S. Pat. No. 4,431,559 discloses a thixotropic composition for automatic dishwashers containing an aqueous solvent, a thickener, a source of chlorine, an anionic surfactant, build-up salts and a buffer system for stabilizing the source of chlorine.

U.S. Patent 3,558,498 discloses a granular laundry detergent composition containing stabilized enzymes, sodium perborate trihydrate, anhydrous trisodium phosphate, anhydrous calcium sulfate and soluble or dispersible proteins of molecular weight 5,000-1,000,000, e.g., molecular weight casein from 50,000 - 200,000.

U.S. Patent 3,560,392 (Continuation-in-Part 3,558,498) discloses a granular detergent composition for laundry good containing organic detergent, alkaline build-up salt, a stabilized enzyme and a stabilizing amount of protein-like collagen with a molecular weight of 5,000 - 250,000.

U.S. Patent 4,238,345 discloses a liquid laundry detergent composition in which the enzyme is stabilized by the addition of an antioxidant and a hydrophilic polyol having 2-6 hydroxyl groups. In column 1 of the patent, it is stated that "-4- calcium salts, combined with proteins, and glycerol, combined with proteins have been used to provide enzyme stabilizing systems in aqueous liquid laundry detergents.

The U.K. patent application G.B. 2,079,305 describes an aqueous built-up liquid laundry detergent composition containing an enzyme in which the enzyme is stabilized by a mixture of a polyol and boric acid.

The invention relates to a polyphosphate-built aqueous liquid composition for dishwashers, which composition contains a stabilized enzyme system containing a boron compound and an α-hydroxycarboxylic acid and a protein-like material, for example casein, and an enzyme.

The stabilization of the enzyme is obtained by premixing a mixture of a boron compound and α-hydroxycarboxylic acid with a mixture of an enzyme and casein while simultaneously blocking the catalytic sites of the enzyme with casein and blocking the enzyme structure with the mixture of the boron compound and the α-hydroxy carboxylic acid.

The enzyme stabilizing system of the invention not only provides very good protease stabilization, but also exhibits very good amylase stabilization, permitting the use of both stabilized protease and stabilized amylase in high alkalinity detergent compositions.

The effective stabilization of amylase enzyme activity is surprising since at a pH above 9 any amylase activity would be expected to be destroyed.

According to the invention, dirty dishes and utensils can be machine washed by contacting the dishes and utensils with an aqueous liquid composition for dishwashers, which composition contains the stabilized enzyme system.

The aqueous liquid dishwashing compositions of the invention can satisfactorily clean both oily and particulate food-containing dishes and utensils. Furthermore, the described compositions can be used for pre-soaking very dirty dishes to be washed in an automatic dishwasher.

7 7, r r. · '· R; f -5-

The invention is based on the discovery that a stabilizing enzyme system, containing a boron compound, an α-hydroxycarboxylic acid, a protein-like material, for example casein, and an enzyme, gives an effective and efficient enzyme stabilizing to the aqueous liquid dishwashing compositions. effect.

in one embodiment, the invention relates to a built up aqueous liquid dishwashing composition comprising an enzyme stabilizing system and a suspension of a detergent phosphate builder salt in an aqueous liquid anionic surfactant detergent.

In another embodiment, the invention relates to an aqueous liquid thixotropic clay-containing dishwashing composition comprising an enzyme stabilizing system and a suspension of a detergent phosphate builder salt in an aqueous liquid anionic surfactant detergent.

It has been found that a stabilizing enzyme system, comprising a mixture of a boron compound, an α-hydroxycarboxylic acid, a proteinaceous material, eg casein, and an enzyme, provides stable, effective enzyme activity over relatively long periods in aqueous liquid dishwashing compositions.

The dishwashing compositions of the invention are physically stable.

The aqueous liquid detergent compositions of the invention are easy to pour, easy to measure, and easy to apply in an automatic dishwasher.

There is a need for an aqueous liquid or an aqueous liquid thixotropic clay-containing dishwashing composition containing a stabilized enzyme system and optionally a physical stabilizing agent.

This need is met by incorporating a stabilized enzyme system into an aqueous thixotropic, for example, normally gelled composition. To improve the physical stability of the dishwashing composition, a small effective amount of a physical stabilizing agent, for example, a fatty acid or a metal salt of a fatty acid, may be included in the composition. More particularly, in a preferred embodiment, the invention relates to a normally gelled dishwashing composition incorporating a stabilized enzyme system comprising a boron compound, an α-hydroxy-β-carbon-carboxylic acid, casein and an enzyme, as well as a physically stabilizing amount of a metal salt of a long chain fatty acid effective to inhibit settling of the suspended particles.

The invention provides a phosphate-based aqueous liquid dishwashing composition containing a relatively simply stabilized enzyme system comprising a boron compound, an α-hydroxycarboxylic acid, a protein-like material, eg casein, and an enzyme. The enzyme stabilizing system provides stabilization over relatively long periods of the active enzyme component such that small amounts of the expensive enzymes can be used.

The invention provides an aqueous phosphate-built anionic surfactant detergent composition containing a stabilized enzyme which composition can be used at an effective high pH of 10-12. The invention also provides an efficient and efficient dishwashing composition which does not use of a chlorine compound required.

In a preferred embodiment, the invention relates to a normally gelled aqueous dishwashing composition to be used in automatic dishwashers having thixotropic properties, containing: 20 (a) 8-35 wt% alkali metal tripolyphosphates, (b) 0-20 wt%, such as 2, 5-20 wt% sodium silicate, (c) 0-9 wt% alkali metal carbonate, (d) 0-5 wt%, such as 0.1-5 wt% water-dispersible organic detergent active material, 25 (e) thixotropic clay thickener in sufficient amount to impart a thixotropy index of 0-10.0, such as about 2.5-10, to the composition, (f) 0.5-2.0 wt% boron compound, (g) 1.5 - 4.0 wt.% Α-hydroxycarboxylic acid, 30 (h) 1 - 4.0 wt.% Casein, (i) 0.5 - 2.0 wt.% Enzyme, (j) 0 - 5 wt. .% suds suppressor, (k) 0-8 wt.% sodium hydroxide, (l) 0-2 wt.% of a metal salt of a long chain fatty acid, (m) water up to 100 wt.% -7-

Related to this aspect, the invention provides a method of cleaning dishes in an automatic dishwashing machine with an aqueous washing bath containing an effective amount of the above described liquid automatic dishwashing detergent (VAVD) composition 5. According to this aspect of the invention, the VAVD composition can be easily poured into the automatic dishwashing dosing bowl, where the composition promptly thickens to its normal gel or paste-like state within a few seconds and then remains securely within the dosing bowl, until shear forces act on it again, for example through the water which is sprayed from the dishwasher.

According to the invention, the activity of the enzyme is stabilized over a relatively long period such that small amounts of the enzyme provide effective enzymatic cleaning activity. The enzyme activity is stabilized by the addition of small effective amounts of a stabilized enzyme system, comprising a boron compound, an α-hydroxycarboxylic acid, a proteinaceous material, eg casein, and an enzyme. The stabilized enzyme system is used in aqueous phosphate-built anionic detergent compositions.

The stabilized enzyme system is preferably prepared separately and then added to the dishwashing composition.

The stabilized enzyme system is preferably prepared in a three-step process as follows.

1. A boron compound is added to an α-hydroxycarboxylic acid or a salt thereof to form a first mixture.

2. The proteinaceous material, for example casein, is added to an aqueous alkali solution and the enzyme is added to the aqueous alkali solution to form a second mixture.

3. The mixture of boron compound and α-hydroxy-carboxylic acid obtained in step 1 is mixed with the mixture of proteinaceous material and enzyme obtained in step 2 to form the premixed stabilized enzyme system according to the invention.

Also, the mixtures obtained in steps 1 and 2 can be added separately to the dishwashing composition, but the best enzyme-stabilizing results are obtained by premixing the mixtures obtained in steps 1 and 2, followed by addition of the premixed cv c C '-8 mixture to the dishwashing composition.

While the invention is not intended to bind to any theory regarding the operation of the stabilized enzyme system, it is believed that the boron compound reacts with the α-hydroxycarboxylic acid or α-hydroxypolycarboxylic acid to form a boric acid ester.

The boric acid ester likely reacts with the enzyme and blocks its structure in the active state so that it is protected from denaturation. The proteinaceous material is likely to block the catalytic sites of the enzyme, preventing the digestion of 10 other enzyme molecules during product storage.

The stabilized enzyme system includes:

A boron compound, e.g. Borax, in an amount of 0.4-2.5 parts by weight, preferably 0.75-2.0 parts by weight and especially 0.9-1.2 parts by weight.

15-hydroxycarboxylic acid in an amount of 1-5 parts by weight, preferably 1.5-4.0 parts by weight and in particular 1.8-3.6 parts by weight.

Protein-like material, for example casein, in an amount of 1 - 6.0 parts by weight, preferably 1-4.0 parts by weight, for example 1.0 - 2.0 parts by weight.

Enzyme in an amount of 0.5-3.0 parts by weight, preferably 0.5-2.0 parts by weight and especially 0.5-1.0 parts by weight.

The weight ratio of α-hydroxycarboxylic acid to boron compound can be between 7: 1 and 1: 1, preferably between 4: 1 and 1: 1, and especially between 3: 1 and 2: 1.

The weight ratio of proteinaceous material, for example casein, to enzyme can be between 8: 1 and 1: 1, preferably between 4: 1 and 1: 1 and in particular between 4: 1 and 2: 1.

A preferred stabilized enzyme system of the invention is composed as follows.

30 parts by weight

Borax

Casein 1.0 - 4.0

Enzyme 0.5 - 2.0 35 The stabilized enzyme system can be added to the dishwashing composition in an amount of 10-30 parts by weight of the stabilized system (-9-stabilized system at 90-70 parts by weight). detergent composition, preferably 15-25 parts by weight of the stabilized system at 85-75 parts by weight of the dishwashing composition, and in particular 15-20 parts by weight of the stabilized system at 85-80 parts by weight of the dishwashing composition. system is added to the dishwashing composition in such a way that the weight percent active ingredients of the enzyme system in the dishwashing composition are equivalent to the above weight parts of the active components in the stabilized enzyme system.

The stabilized enzyme system of the invention can be used in aqueous liquid dishwashing compositions, aqueous liquid thixotropic dishwashing compositions and powder or granular dishwashing compositions.

Preferably, the stabilized enzyme system of the invention is added to an aqueous liquid thixotropic dishwashing composition.

The α-hydroxycarboxylic acids to be used according to the invention are organic carboxylic acids with 3-8 carbon atoms, containing 1-3 carboxyl groups and 1-3 hydroxy groups.

Preferred carboxylic acids are the α-hydroxycarboxylic acids with 3-6 carbon atoms containing 1-3 carboxy groups and 1-2 hydroxy groups. Examples of suitable α-hydroxycarboxylic acids are malic, tartaric, lactic and citric acids. Tartaric, lactic and citric acids are preferred, with citric acid being most preferred. The α-hydroxycarboxylic acids can be used as such or as their alkali metal salts, such as sodium and potassium r salts.

The boron compounds to be used in the dishwashing compositions of the invention are those which are water soluble and form boric acid or an alkali metal salt of boric acid when added to water. Suitable boron compounds are boric acid, boron oxide or an alkali metal borate. Suitable alkali metal borates are sodium and potassium ortho, pyro and metaborates, polyborates and borax. Boric acid, sodium borate and borax are preferred.

The enzymes to be included in the dishwashing compositions of the invention can be proteolytic or amylolytic enzymes or mixtures thereof. Examples of suitable proteolytic enzymes are the various commercially available liquid, powder or suspension, enzyme preparations, which are adapted for use in detergent compositions.

Although the incorporation of the enzyme into the composition is most suitably in liquid form, the enzymes in the form of a suspension have proved very useful.

Examples of suitable liquid enzyme preparations are "Alcalase" and "Esperase" marketed by Novo Industries, Copen-10 hedges, Denmark, "Maxatase" and "Maxacal" marketed by Gist-Brocades, Delft, "Optimase", marketed by Miles Kali Chemie. Examples of suitable proteolytic enzymes are subtilisin, bromelin, papain, trypsin and pepsin. Other suitable enzymes are liquid protease and liquid amylase. The enzymes are preferably used in the form of their solutions. A preferred enzyme is Esperase 8L in the form of a solution. Suitable ct-amylase liquid enzyme preparations are marketed by Novo Industries and Gist-Brocades under the trade names "Termamyl" and "Maxamyl", respectively. A preferred enzyme is Termamyl 120L. "Esperase" 8L 20 is preferred for the present compositions because of its activity at the higher pH values corresponding to those of the built-up detergent compositions. Another preferred enzyme is Esperase 8.0L because of its high activity at 60 ° C and its low activity at room temperature. Furthermore, "Esperase 8.0L is stable at a high pH, allowing the final product to have a higher pH and better detergency.

One of the enzyme stabilizing components of the invention is a protein-like material, preferably casein. The proteinaceous materials are used as their water-soluble alkali metal salts (eg, sodium and potassium) and / or are dispersed in an aqueous medium to which the enzyme is added.

Proteins that are soluble or dispersible in water are used in an effective amount to stabilize the enzymes. Examples of proteins which are soluble or dispersible in water and suitable for use according to the invention are casein (average molecular weight 50,000-200,000); Wilsons Protein Ü V · · V? * / Λ * -11- WP-X-1000 (a solubilized collagen with an average molecular weight of about 10-000) and Wilson's Hydrolyzate Cosmetic 50, both marketed by Wilson's Pharmaceutical & Chemical Company; and Collagen Hydrolyzate Cosmetic 50, marketed by Maybrook, 5 Ine. A preferred casein protein is marketed under the trade name "Sodium Caseinate" by Bridal (France) or Dena, A.G.

(Germany). Sodium Caseinate is a mixture of various caseins with different molecular weights. The proteins, for example casein, are normally available as powders. The proteins, such as casein, have long chemical chains. In the powder form, the chains are folded and form hydrogen bonds, keeping the protein spherical. Expanding or denaturing the protein involves breaking these bonds to form a looser, more random structure. The proteins can be denatured. by cooking, using acids, alkali and various detergents. The expanded or denatured proteins are more easily digested by enzymes, thereby providing a better stabilizing effect, and in particular, better enzyme stability. Denaturing makes the protein more effective as a stabilizing agent. The protein, eg casein, is used in an amount sufficient to effect stabilization of the enzyme activity.

In general, the effectiveness of a thixotropic clay-containing aqueous dishwashing composition is related to (a) alkalinity, (b) solubility in the wash medium and (c) foam inhibition. Preferably, the pH of the VAVD composition is at least about 9.5, more preferably about 10.5-12.5, and most preferably at least about 11.5. At the relatively lower pH values, the detergent detergent product is too viscous, especially resembling a solid material, so that it does not readily liquefy at the level of the shear forces created in the dosing cup under the normal operating conditions of the dishwasher. is becoming. In essence, the composition largely, if not entirely, loses its thixotropic character. Therefore, addition of NaOH is often necessary to raise the pH to within the above ranges and improve the flowability properties. The presence of carbonate is also necessary, as this helps to maintain the desired pH level as a buffer. However, an excess of carbonate -12- should be avoided as it can cause the formation of needle-like carbonate crystals and thereby impair the stability, thixo-tropics and / or detergent of the VAVD product, as well as the dosability of the product from squeeze bottles, for example can adversely affect 5. NaOH has the further function of neutralizing the phosphoric or phosphonic acid ester optionally present as a foam suppressant. Levels of 0.5-3 wt% NaOH and 2-9 wt% sodium carbonate in the VAVD composition are typical, although it may be noted that sufficient alkalinity can be provided by the sodium tripoly-10 phosphate and the sodium silicate . The sodium silicate can be used in amounts of 0-20% by weight, preferably from 2.5-20% by weight and especially from 5-15% by weight.

Sodium tripolyphosphate is used in the VAVD composition in an amount of 8-35 wt%, preferably 20-30 wt%. The sodium tripolyphosphate can be anhydrous or hydrated, for example, as the stable hexahydrate with a degree of hydration of 6, corresponding to about 18% by weight of water or more. In view of the stability of the hexahydrate, the presence of some hydrate water is in fact very effective since it is believed to germinate the stable hexahydrate, thereby promoting hydration and solubilization of the remaining sodium tripolyphosphate particles. If only the hexahydrate is used, the detergent product may be too liquid and have little or no thixotropic character. Conversely, if only the anhydrous sodium tripolyphosphate is used, in some cases the product may be too thick and therefore unsuitable. Particularly preferred VAVD compositions are obtained, for example, when using a weight ratio of anhydrous sodium tripolyphosphate to the hexahydrate between 0.5: 1 and 2: 1, with a ratio of about 1: 1 being particularly preferred.

Foam inhibition is important in order to increase the efficiency of the dishwasher and to minimize the destabilizing effects which could occur during use due to the presence of excess foam within the washing machine. Foaming can be sufficiently reduced by appropriate selection of the type and / or amount of detergent active material, the major foam-producing component. The degree of foaming also depends to some extent in jrv **** ΓΙ \ 7 "*? C * WV, v f.: -13-« depending on the hardness of the washing water in the machine, whereby an appropriate adjustment of the amount of sodium tripolyphosphate, which has a water-softening effect, can help provide the desired degree of foam inhibition, nevertheless, if a low foaming VAVD is desired, a suds suppressor or inhibitor may be included. the alkylphosphon-

acids of the formula O.

II

HO - P - R

OR

Commercially available for example from BASF-Wyandotte (PCUK-PAE), and in particular the alkyl acid phosphate esters of the formula O

II

HO - P - OR I

OR

Commercially available, for example, from Hooker (SAP) and Knapsack (LPKn-158), in which one or both groups R in each type of ester can independently represent a 2Q-alpha glyph. Mixtures of the two types or mixtures of mono- and diesters of the same type can also be used. Particular preference is given to a mixture of mono- and di-C 1 -C 20 alkyl acid phosphate esters, such as monostearyl / distearyl acid phosphates 1.2 / 1 (Knapsack). When used, amounts of 0.1-5 wt%, preferably 0.1-0.5 wt%, of the foam suppressor in the composition are typical, the weight ratio of the detergent active component (d) to foam suppressor (j) in it is generally between about 10: 1 and 1: 1, and preferably between about 4: 1 and 1: 1. Other anti-foaming agents which can be used are, for example, the known silicones.

The sodium silicate, which provides alkalinity and hard surface protection, such as glaze and fine porcelain pattern, is used in the composition in an amount of 2.5-20% by weight, preferably 5-15% by weight. The sodium silicate is generally added in the form of an aqueous solution, preferably with a Na 2 O: SiO 2 ratio of 1: 2.2 to 1: 2.8. It is worth noting that most other components of the composition, especially 35

NaOH, suds suppressor and thixotropic thickener, often also in the -14 form of a pre-prepared aqueous dispersion or solution are added.

Suitable detergent active materials are the water-dispersible surfactant organic anionic, amine oxide, phosphine oxide, sulfoxide or betaine types. The anionic surfactants are preferred. The surfactants, for example anionic surfactants, are used in amounts of 0.1-5%, preferably 0.3-2.0%. Particularly preferred surfactants are the linear or branched alkali metal mono- and / or 10 di- (CQ.) - alkyl diphenyloxoxide mono- and / or di-sulfates which are for example commercially available under the trade names DOWFAX 3B-2 and DOWFAX 2A-1. The paraffin sulfonates generally adversely affect and can even destroy thixotropy as they increase the viscosity undesirably, causing serious shear problems. Furthermore, the surfactant should be compatible with the other components of the composition. Other suitable surfactants are the primary alkyl sulfates, alkyl sulfonates, alkyl aryl sulfonates, and secondary alkyl sulfates. Examples are sodium C 1 -C 2 C 4 alkyl sulfates, such as sodium dodecyl sulfate and sodium tallow alcohol sulfate; sodium C -C. alkane sulfonates, such as 1U 10 sodium hexadecyl-1-sulfonate and sodium C 1 -C alkyl benzene sulfonates, 12, 18 such as sodium dodecyl benzene sulfonates. The corresponding potassium salts can also be used. Examples of suitable alkyl sulfonates are the - C 1 -g primary alkyl sodium and potassium sulfonates, with the - C 1 -g primary n-alkyl sodium sulfonate salt being preferred.

Typically, amine oxide surfactants have the structure RR ^ NO, wherein each R represents a lower alkyl group, e.g., methyl, and R is a long chain alkyl group of 8 to 22 carbon atoms, e.g., a lauryl , myristyl, palmityΙ- ΙΟ or cetyl group. Instead of an amine oxide, a corresponding 1 liter of capillary active phosphine oxide R, R PO or sulfoxide RR SO can be used. Betaine surfactants typically have the structure R 1, R 1, N-R'COO-, wherein each R represents a lower alkylene group with 1 to 5 carbon atoms. Specific examples of these surfactant compounds are lauryldimethylamine oxide, myristyldimethylamine oxide, the corresponding phosphine oxides and sulfoxides, and the corresponding -, f, f f f ΓΧ f ΓΧ f> f>>>>>>>>>>>>>>>>>>

"1 -15-betaines, including dodecyldimethylammonium acetate, tetradecyldiethyl ammonium pentanoate, hexadecyldimethylammonium hexanate and the like.

For the biodegradability, the alkyl groups in these surfactants are linear, and such compounds are preferred.

Surfactants of the types described are known and described, for example, in U.S. Patents 3,985,668 and 4,271,030.

Thixotropic thickeners, especially thickeners or suspending agents which impart thixotropic properties to an aqueous medium, are known and may be organic or inorganic water-soluble, water-dispersible or water-forming monomeric or polymeric materials, and of course serve in the compositions of the invention to be stable, for example, resistant to high alkalinity. Particularly preferred thickeners are generally the inorganic colloid-forming clays of smectite and / or attapulgite types. The organic thixotropic clay thickeners can also be used. These materials are generally used in amounts of 1.5-10 wt%, preferably 2-5 wt% to impart the desired thixotropic properties and Bingham plastic character in the earlier in GB 2.116.199A and GB 2,140,450A described VAVD compositions. According to the invention, amounts of the inorganic colloid-forming clay materials of the smectite and / or attapulgite type are 0.25 - 5%, preferably 0.50 - 4.0%, in particular 1.0 - 3 %, generally sufficient to achieve the desired thixotropic properties and Bingham plastic character. Also, smaller amounts of the thixotropic agent can be used when used in combination with the fatty acid metal salt as a physical stabilizer.

Examples of smectite clay materials are montmorillonite (bentonite), hectorite, attapulgite, smectite, saponite and the like. Montmorillonite clay materials are preferred and are available under brand names such as Thixogel No. 1 and Gelwhite GP, H, etc. from Georgia Kaolin Company; and ECCAGUM GP, H, etc. from Luthem Clay Products. Atta-35 pulgite clay materials are commercially available under the brand name Attagel, for example Attagel 40, Attagel 50 and Attagel 150 from 3 -16-

Engelhard Minerals and Chemicals Corporation. According to the invention, mixtures of smectite and attapulgite types in weight ratios from 4: 1 to 1: 5 can be used. Thickeners or suspending agents of the aforementioned types are known and are described, for example, in the said US patent 3,985,668. Abrasives or polishes should be avoided in the VAVD compositions, as they can damage the surface of fine porcelain, crystal and the like.

The amount of water in the compositions should, of course, not be such that the viscosity and the fluidity are undesirably reduced, or so small as to cause an undesirably high viscosity and low fluidity, in either case the thixotropic properties are reduced or destroyed.

A suitable amount can be easily determined by routine tests 15 and is generally between 35 and 65% by weight, preferably between 40 and 55% by weight. The water is preferably deionized and softened.

The VAVD products according to the earlier U.K. patent applications GB 2,166,199A and GB 2,140,450A exhibit improved rheological properties, as evaluated by testing product viscosity as a function of shear. The compositions exhibit a higher viscosity at a lower shear and a lower viscosity at a high shear, the data showing efficient fluidity and gel formation within the shear values found in the standard dishwashing machine. In practical terms, this means improved casting utilization properties, as well as less leakage into the dosing cup of the machine compared to earlier liquid or gel AVD products. For shear forces, corresponding to 3-30 rpm, the viscosities (Brookfield) are at corresponding between 10,000 -30 30,000 cps and 3,000 - 7,000 cps, measured at room temperature using an LVT Brookfield viscometer after 3 minutes with a No. 4. A shear value of 7.4 sec * corresponds to an axis speed of about 3 rpm. An approximately ten-fold increase in the shear value provides about a 3- to 9-fold reduction in viscosity. With previous AVD gels, the corresponding decrease in viscosity was only about 2-fold. Furthermore, with such compositions

.. <* - r * r ί V V

5 -17- the initial viscosity, determined at about 3 rpm, only about 2,500-2,700 cps. The compositions according to the aforementioned U.K. Patent applications thus exhibit threshold fluidizations at lower shear rates and to a significantly greater degree in terms of incremental shear rate increase versus incremental viscosity decrease. This property of the VAVD products according to the aforementioned U.K. Patent applications are summarized in terms of a thixotropy index (TI) which is the ratio of apparent viscosity, at 3 rpm and at 30 rpm. The earlier compositions have a TI of 2 - 10. The 10 tested VAVD compositions showed a marked and rapid return to the previous resting state consistency, when the shear force was discontinued.

United States patent application 903,924, filed September 5, 1986, is based on the discovery that the physical stability, especially the resistance to phase separation, settling and the like of the liquid aqueous AVD compositions of the U.K. patent applications GB 2,116,199A and GB 2,140,450 can be markedly improved without adversely affecting, and in some cases even adversely affecting, their rheological properties by adding to the composition 20 a small but effective amount of a metal salt of a fatty acid with long chain.

As an example of improving the rheological properties, it can be mentioned that the viscosities at low shear values #, for example, at an axis speed of about 3 rpm, the apparent viscosities can often be increased 2 to 3-fold by incorporating so little as 0.2% or less, for example 0.16%, of the fatty acid metal salt as a stabilizer. At the same time, the physical stability can be improved such that the compositions containing the fatty acid metal salt as a stabilizer do not undergo visible phase separation after a prolonged stay of 12 weeks or longer at temperatures ranging from near freezing point to 40 ° C and above.

The preferred long chain metal salts of fatty acids are the same as those disclosed in U.S. Patent Application 903,924. Suitable metal salts are those of aliphatic fatty acids with 8-22 carbon atoms, preferably 10-20 carbon atoms, especially 12-18 carbon atoms, including the carbon atom of the carboxyl group -18- of the fatty acid. The aliphatic group can be branched or unbranched and saturated or unsaturated. Unbranched saturated fatty acids are preferred. Mixtures of fatty acids, such as fatty acids from natural sources, for example tallow fatty acid, coco fatty acid, soy fatty acid and the like, or fatty acids from synthetic sources, available from industrial preparation processes, can also be used.

Examples of fatty acids from which the metal salt stabilizers can be formed are decanoic acid, dodecanoic acid, palmitic acid, myristic acid, stearic acid, oleic acid, eicosanoic acid, tallow fatty acid, coco fatty acid, soy fatty acid, and mixtures of these acids. Stearic acid and mixed fatty acids are preferred.

The preferred metals are the polyvalent metals, such as magnesium, calcium, aluminum and zinc.

Many of these metal salts are commercially available. For example, the aluminum salts are available in the triacid form, for example, aluminum stearate as aluminum tristearate. The mono acid salts, for example aluminum monostearate, and diacid salts, for example aluminum distearate, and mixtures of two or three of the mono-, di- and triacid salts can be used for metals, for example aluminum-20 µm, with valencies of +3, while mixtures of the mono and diacid salts can be used for metals, such as zinc, with valencies of +2.

Calcium stearate, especially calcium distearate, magnesium stearate, especially magnesium distearate, aluminum stearate, especially aluminum tristearate, and zinc stearate, especially zinc distearate, are preferred as fatty acid salt stabilizers.

For VAVD compositions, as well as for other applications, in which the composition according to the invention will or may come into contact with objects that are used for the handling, storage or serving of food products or that can come into contact in other ways with or consumed by humans or animals, the use of the fatty acids as a stabilizing agent is of particular advantage because of their known low toxicity. For this purpose, calcium stearate, in particular calcium distearate, and magnesium stearate, in particular magnesium distearate, are particularly preferred as a generally safe additive for food products.

The amount of the fatty acid metal salt required for the ·. Achieving the desired improvement in physical stability depends on various factors, such as the nature of the fatty acid salt, the nature and amount of the thixotropic agent, detergent active compound, inorganic salts, especially tripolyphosphate, other VAVD components, as well as the intended storage and transportation conditions.

Generally, however, amounts of the fatty acid metal salt of 0.2 - 2%, preferably 0.5 - 1.0%, and especially 0.5 - 0.8% provide the long-term stability and absence of phase separation during standing or during transport at both low and elevated temperatures, as required for a commercially acceptable product.

Depending on the amounts, ratios and types of physical stabilizers and thixotropic agents, the addition of the fatty acid metal salt would not only increase physical stability, but would also provide an apparent increase in apparent viscosity. Fatty acid to thixotropic agent ratios of about 0.08-0.4 wt% fatty acid and about 1.3-2.5 wt% thixotropic agent are usually sufficient to provide these concurrent benefits, so that the use of these components most preferred in said ratios.

According to a method for the preparation of these compositions, all inorganic salts, in particular carbonate (if used), silicate and tripolyphosphate, can first be dissolved or dispersed in the aqueous medium. The thickener (if used) is added just before the stabilized enzyme system. The suds suppressor 25 (if used) is pre-placed in aqueous solution, as is the thickener. The dispersion of the suds suppressor, NaOH (if used) and inorganic salts are required while stirring at elevated temperature mixed in aqueous solution (deionized water) and then cooled with stirring. Capillary active material, fatty acid stabilizer and thickener dispersion are then added to the cooled (25-25 ° C) solution at room temperature.

The stabilized enzyme system of the invention is added last. The total salt concentration (sodium tripolyphosphate, sodium silicate and carbonate) is generally 20-50 wt.%, Preferably 30-40 wt.% Of the composition. The stabilized enzyme system is generally 15-25 parts by weight, preferably 15-20 parts by weight, of -20- of the composition.

According to another method of mixing the components. of the VAVD composition, a mixture is first formed of the water, suds suppressor (if used), detergent, physical stabilizer, for example fatty acid salt (if used) and thixotropic agent, for example clay (if used). These components are mixed under high shear conditions, preferably starting at room temperature, to form a uniform dispersion. To this premixed portion, the remaining components are added with low shear mixing. For example, the required amount of the premix is placed in a low shear mixer, after which the other components are added sequentially or simultaneously with mixing. Preferably, the components are added sequentially, although it is not necessary that the addition of the entire amount of one component has been completed before the addition of the next component is started. One or more components can also be divided into portions and added at different times. Good results were obtained by adding the other components in the following order: sodium hydroxide, alkali metal carbonate, sodium silicate, alkali metal tripolyphosphate (hydrated), alkali metal tripolyphosphate (anhydrous or with a water content of up to 5%), sodium hydroxide and lastly the stabilized enzyme system.

Minor amounts, generally less than about 3% by weight, may be included in the compositions of other conventional components such as perfume, hydrotropic agents such as the sodium benzene, toluene, xylene and cumene sulfonates, preservatives, dyes and pigments and the like, all of which, of course, must be able to withstand higher alkalinity (properties of all components). Especially preferred dyes are the chlorinated phthalocyanines and polysulfides of aluminosilicate, which give pleasant green and blue tones, respectively. TiO ^ can be used for whitening or neutralizing color deviations.

The liquid AVD compositions according to the invention can easily be used in known manner for washing crockery, kitchen utensils and the like in an automatic dishwasher, which is pre-washed. Has been seen from a suitable detergent dispensing bowl, in an aqueous wash bath, containing an effective amount of the composition.

While the invention has been particularly described in connection with its use for aqueous thixotropic clay-containing automatic dishwashing detergents, it will be appreciated by those skilled in the art that the benefits obtained by the addition of the stabilized enzyme system include: apply equally to aqueous liquid dishwashing compositions and powdered dishwashing compositions.

The invention is further illustrated by the following examples, in which all amounts and proportions relate to the weight of the composition, unless otherwise stated.

Example I.

A stabilized enzyme system according to the invention was prepared in the following manner.

(1) 12.6 g of sodium borate (Na 2 BO 4) were added with stirring to 56.1 g of tartaric acid in 90 g of water. The mixture was neutralized 56.1 g of NaOH (50% solution) to a pH of about 7.

(2) 60 g of casein (Bridel) was added with stirring and heating to 270 g of water containing 1.8 g of NaOH. After everything had dissolved, 15 g of Esperase 8.QL were added at 50 ° C and 9 g of Termamyl 120L were added at room temperature to form a casein / enzyme mixture.

(3) The mixtures obtained in steps (1) and (2) were mixed together to form the premixed stabilized enzyme system of the invention.

The entire premixed stabilized enzyme system (about 570.6 g) can be incorporated into an aqueous liquid dishwashing composition or an aqueous liquid thixotropic clay-containing dishwashing composition to form about 3,000 g of dishwashing composition, wherein the stabilized enzyme system of the invention is is present in the following amounts.

♦ -22-

Wt. %

Na3B03 0.4

Tartaric acid 1.9

Casein 2.0 5 Esperase 8.0L 0.5

Termamyl 120L 0.3

Dishwashing compositions containing the stabilized enzyme system of the invention have been found to effectively clean dirty dishes, even in the absence of compounds providing active chlorine. Example II.

In the manner described in Example I, a stabilized enzyme system was prepared containing the following components.

Parts 15 Na2B4O7110H2O 0.8

Citric acid 2.6

Casein 2.0

Esperase 8.0L 0.5

Termamyl 120L 0.3 20

A thixotropic clay-containing dishwashing detergent composition was prepared, after which about 19 parts of the stabilized enzyme system described above was added to about 81 parts of the dishwashing detergent composition to form the following composition.

25 wt%

Deionized water 43.7 50% NaOH solution 2.2

Sodium carbonate (anhydrous) 5.0

Sodium silicate (47.5% solution; Na2O: SiO2 1: 2.4) 15.74

Sodium polyphosphate (virtually anhydrous, i.e. with 0-5%, preferably 3% moisture) (Thermphos NW) 12.0

Sodium tripolyphosphate (hexahydrate) (Thermphos N hexa) 12.0 35 Na2B4 ° 7 "10H2 ° 0.8

Citric acid 2.6 B "Λ ί1" '1 1 t 1 <'

Wt. % * -23-

Casein 2.0

Esperase 8.0L 0.5

Termamyl 120L 0.3 5 Monostearyl Phosphate 0.16 DOWFAX 3B-2 (45% aqueous solution of Na monodecyl / didecyl diphenyloxisulfonate) 0.80

Aluminum stearate 0.20

Pharmagel H (thixotropic clay) 2.0 10 100.00

Example III.

The aqueous liquid thixotropic dishwashing composition of Example II with the stabilized enzyme system of the invention, containing 0.5 wt% Esperase 8.0L and 0.3 wt. % Termamyl 120L enzymes were tested for proteolytic activity and amylolytic activity after aging at 4 ° C, room temperature and 35 ° C for 1, 4 and 8 weeks. The dishwashing detergent composition had a pH of about 11.7. The results obtained are shown in the following table.

20

Aging temperature 4 ° C Room temperature 35 ° C

Aging period (weeks) _12 4_12 4_12 4

Proteolytic activity 77 - 58 - - 51 38 - 32

Amylolytic activity - 50 - - 22 - - 4 - 25

The enzyme system stabilized with borax citric acid and casein-Esperase and Termamyl according to the invention shows not only a stabilization of amylase under very harmful conditions (amylase is normally destroyed at a pH of 9), but also an observed amylolytic activity at a high alkaline pH. The dishwashing detergent composition actually showed amylolytic activity in the dishwashing composition after 5 months of storage at room temperature.

Upon further testing, it was found that the efficiency of the hard waste composition described above was greater than for any commercially available AVD, particularly at a low concentration in the dishwasher of 5 g / l.

\ -24-

Example IV.

An aqueous liquid dishwashing detergent composition according to the invention is prepared which is suitable for washing dishes by hand and for soaking particularly dirty dishes before they are machine washed. The composition is composed as follows.

Wt. %

Deionized water 46.1 50% NaOH solution 2.2 10 Sodium carbonate (anhydrous) 5.0

Sodium Silicate (47.5% solution; Na2O: SiC2: 1: 2.4) 15.74

Sodium TPP (Thermphos NW) 12.0

Sodium TPP (Thermphos N hexa) 12.0 15 Na2B4 ° 7 * 10H2 ° 0.9

Lactic acid 1.8

Casein 2.0

Esperase 8.0L 0.8

Monostearyl Phosphate 0.16 20 DOWFAX 3B-2 (45% aqueous solution of Na monodecyl / didecyl diphenyloxydisulfonate) 0.80

Aluminum stearate 0.50 100.00 The dishwashing detergent compositions of the invention containing a stabilized enzyme system can also be formulated as powdered dishwashing wax compositions.

h / f -j ί-

Claims (27)

An aqueous liquid dishwashing composition containing water, an alkali metal phosphate build-up salt and an organic surfactant material, characterized by a stabilized enzyme system comprising a boron compound, a carboxylic acid, a protein-like material and an enzyme. Composition according to claim 1, characterized by at least one boron compound selected from borax (Na ^ B ^ O ^ * 10HHO), sodium borate (Na ^ BO ^), boric acid and boron oxide. Composition according to claim 1, characterized in that the proteinaceous material is casein. Aqueous liquid dishwashing composition, characterized by the following composition: Wt% Water 35 - 65 Alkali metal phosphate build-up salt 8 - 35 15 Sodium silicate 0-20 Organic surfactant compound 0-5 Boron compound 0.4 - 2 Carboxylic acid 1 - 5 20 Protein-like material 1 - 6 Enzyme 1 - 6 Composition according to claim 4, characterized by 0-5% by weight of a thixotropic clay thickener. 6. Composition according to claim 4, characterized in that the boron compound is selected from borax (Na ^ B ^ O ^ 10 OH ^ O), sodium borate (Na ^ BO ^) boric acid and boron oxide, and that the carboxylic acid is an α-hydroxycarboxylic acid. Composition according to claim 4, characterized by the following composition: Water 40 "55 30 Sodium tripolyphosphate (TPP) 20 ~ 30 Inorganic surfactant 0 ~ 5 Sodium silicate 0 _ 20 Wt. % <* -26- Sodium carbonate 0 9 Anti-foaming agent 0 5 Borax (Na2B407.10H20) 0.75 - 2.0 5 α-hydroxycarboxylic acid 1.5 - 4.0 Casein 1.0 - 4.0 Enzyme 0.5 - 2.0 Composition according to claim 7, characterized in that the organic surfactant is sodium linear tridecylbenzene. 9. Composition according to claim 7, characterized in that the α-hydroxycarboxylic acid is selected from lactic acid, tartaric acid, citric acid and the sodium salts thereof. Composition according to claim 7, characterized in that the α-hydroxycarboxylic acid is citric acid and its sodium salt. Composition according to claim 4, characterized by the following composition: Wt% Water 40 - 55 Sodium tripolyphosphate 20 - 30 20 Thixotropic clay thickener 0.25 - 5.0 Anionic surfactant C, 1 - 5 Sodium silicate 0 - 20 Sodium carbonate 2 - 9 25 Anti-foaming agent 0.1 - 0.5 Borax (Na2Ba407 <10H2O) 0.75 - 2.0 α-hydroxycarboxylic acid 1.5 - 4.0 Casein 1.0 - 4.0 Enzyme 0.5 - 2.0 12. Composition according to claim 11, characterized in that the anionic surfactant compound is sodium linear decyl sulfonate. Composition according to claim 11, characterized in that the α-hydroxycarboxylic acid is selected from lactic acid, tartaric acid, citric acid and the sodium salts thereof. Aqueous thixotropic detergent composition for use in an automatic dishwasher, characterized by the following composition: ef / - Λ -27-% by weight. Water 40 - 55 Sodium tripolyphosphate 20 - 30 Thixotropic clay thickener 0.5 - 4.0 5 Sodium silicate 2.5-20 Sodium carbonate 2 - 9 Anionic surfactant 0.3 - 2.0 Borax (Na 2 O. 10H 0) 0.75-2.0 α-hydroxycarboxylic acid 1.5 - 4.0 Casein 1.0 - 4.0 Enzyme 0.5 - 2.0 15. A composition according to claim 14, characterized by a metal salt of a long chain fatty acid stabilizing agent in an amount sufficient to increase the physical stability of the composition. Composition according to claim 15, characterized in that the physical stabilizing agent is aluminum stearate. Composition according to claim 15, characterized in that the physical stabilizing agent is present in an amount of 0.1-2 20% by weight. The composition according to claim 14, characterized in that the thixotropic thickener is an inorganic or organic colloid-forming clay. 19. A composition according to claim 14, characterized in that the clay is a montmorillonite clay, an attapulgite clay, a hectorite clay or a smectite clay. Composition according to claim 14, characterized by 0.1-0.5% by weight of an anti-foaming agent. 21. A method of cleaning dirty dishes, characterized in that the dirty dishes are brought into contact with the aqueous liquid dishwashing composition according to claim 1. A method for cleaning dirty dishes in an automatic dishwasher, characterized in that the dirty dishes in an automatic dishwasher are brought into contact with an aqueous washing bath, in which an effective amount of the composition according to claim 7 is dispersed. -28- 23. A method for cleaning dirty dishes in an automatic dishwasher, characterized in that the dirty dishes in an automatic dishwasher are brought into contact with an aqueous washing bath in which an effective amount of the composition according to claim 14 is dispersed. © 7 * i U * /. v. * = · '