CA1231652A

CA1231652A - Aqueous enzyme-containing compositions with improved stability

Info

Publication number: CA1231652A
Application number: CA000452693A
Authority: CA
Inventors: Jelles V. Boskamp
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 1983-04-26
Filing date: 1984-04-25
Publication date: 1988-01-19
Also published as: ATE24740T1; EP0126505A1; NZ207918A; NO158427B; AU2708084A; DK207484D0; NO158427C; US4532064A; JPS59217799A; GB8311314D0; JPS6125757B2; GR80000B; DK207484A; EP0126505B1; PT78474B; ZA843057B; AU555127B2; BR8401898A; DE3461936D1; PT78474A

Abstract

Abstract of the disclosure The invention pertains to aqueous, enzymatic liquid detergent compositions which contain an enzyme-stabi-lizing system. The replacement of polyols in known enzyme-stabilizing systems on the basis of mixtures of a polyol with a boron compound, such as boric acid or borax, or with a reducing salt, such as sodium sulphite, by a dicarboxylic acid, such as succinic acid, also provides for an effective, often superior enzyme-stabilizing system.

Description

~3~5~ C 826 (R) AQUEOUS ENZYME-CONTAI~ING COMPOSITION WITH IMPROVED
STABILITY

The present invention relates to a stabilizing agent for aqueous enzyme-containing compositions.

It is well-known that enzymes, when included in aqueous media, often tend to lose their activity on storage over longer periods. This is particularly so when the aqueous media contain other ingredients as well, which may accelerate the deactivation of enzymes.
Such is for instance often the case if the aqueous media are aqueous liquid detergent compositions.

In the prior art numerous proposals have been made concerning enzyme stabilizers in aqueous enzyme-containing liquid detergent compositions. Suck enzyme-stabilizing systems often comprise a polyol, such as glycerol or sorbitol. Recently we have proposed as enzyme-stabilizing system a mixture of a polyol and a boron compound in our Dutch patent application No. 7711925, laid open to public inspection on 3 May 1978.

Another proposal is made in UK Patent Specification No 2,021,142 (Economics Laboratories Inc.) to use a mixture of a polyol and a sulphur-containing anti-oxidant salt as enzyme-stabilizing mixture.

We have now found that the use of certain dicarboxylic acids instead of the polyol in the above systems equal-lye provides for an enzyme-stabilisation effect. In some instances this effect is even superior to that which is obtained with the polyol-containing systems.

~3~5~ C 826 (R) In its broadest aspect therefore the present invention relates to an aqueous enzyme-containiny liquid combo-session comprising an enzyme-stabilizing system which comprises a mixture of:
(a) boric acid, boric oxide or an alkali metal borate, alnd/or a reducing alkali metal salt having an oxygenated Selfware anion Sob in which a and b are whole numbers from 1 to 8; and (b) a dicarboxylic acid of the general formula:
COO
I

(HC-OH)a I

(Schwab I

(HCOH)C
I

(Chad KIWI, in which a, b, c, d are whole numbers from 0 to 4, the sum of a, b, c and d being from 0-4, or the alkali metal, ammonium, alkanolamine or alkaline earth metal salts thereof.

More particularly, the present invention relates to aqueous, liquid enzyme-containing detergent compositions incorporating the above mixture of (a) and (b) as enzyme-~tabilizing system.

I C 826 (R) Component (a) can comprise, or consist of, boric acid, boric oxide or an alkali metal borate. Typical examples of alkali metal borate are sodium and potassium, ortho-, pyre- and meta-borates, -polyborates, and borax. Borax is the preferred alkali metal borate.

If component (a) comprises, or consists of, boric acid, boric oxide, or an alkali metal borate, the amount thereof ranges from 1 to 15, preferably from 3 to 10~
by weight of the final aqueous enzyme-containing combo-session.

Component (a) can also comprise, or consist of, a no-during alkali metal salt having an oxygenated Selfware anion Sob in which a and b are whole numbers from 1 to 8. Typical examples of such reducing salts (which have an anti-oxidant effect) are sodium and potassium sulk whites, -bisulphites, -metabisulphites and -thiosul-plates. Sodium sulfite is the preferred reducing alga-it metal salt.

If component pa) comprises, or consists of, the no-during alkali metal salt, the amount thereof ranges from 2 to 20, preferably from 5 to 15% by weight of the final aqueous, enzyme-containing composition.

Component (a) may also consist of mixtures of the various recited ingredients.

Component (b) consists of a dicarboxylic acid of the above general formula or mixtures of these acid ;
instead of the acids, the androids can by used, or the alkali metal, ammonium, alkanolamine or alkaline earth metal salts of these acids. Typical examples of C 826 (R) suitable dicarboxylic acids are oxalic acid, Masonic acid, succinic acid, glutaric acid, adipic acid, tartronic acid, mafia acid, tartaric acid, xylaric acid, arabimaric acid, glucaric acid, music acid and S saccharin acid. In general, when arc = 0, the dicarbo-xylic acids of -the general formula with b + d - 0-2 are preferred over those with b + d = 3-4, and if b + d = 0, a + c = preferably 4. When a = c = 0 and b = d = 1, the corresponding unsaturated dicarboxylic acid, viz malefic or ~umaric acid, may alto be used.

The amount of the acids) used ranges from 0.5-15, preferably from 2-10% by weight of the final aqueous enzyme-containing composition. Succinic acid or sac-kirk acid or the alkali metal or alkanolamine salts thereof are the preferred compounds, since they provide for an enzyme-stabilizing effect which it equal or sup prior to the effect obtained with the corresponding polyol-containing systems. As alkanolamine salts the moo-, dip or triethanolamine salts can be used as well as the corresponding isopropanol amine salts. The salts of the acids can also be formed in situ in the final composition by neutralization with the required base.

The preferred enzyme-stabilizing system according to the present invention comprises a mixture of sodium sulfite, borax and disodium succinate.

The aqueous liquid compositions in which the stabile-zing systems of the invention are incorporated are preferably aqueous, liquid enzymatic detergents combo-sessions further comprising as essential ingredients enzymes, and active detergents.

The enzymes to be incorporated can be proteolytic, typo-lyric, amylolytic and cellulolytic enzymes as well as mixtures thereof. They may be of any suitable origin, I C 826 (R) such as vegetable, animal, bacterial, finagle and yeast origin. However, their choice is governed by several factors such as pi activity and/or stability optima, thermostat ability, stability versus active detergents, builders and so on. In this respect bacterial or finagle enzymes are preferred, such as bacterial amylases and pro teases and finagle cellulases. Although the liquid compositions of the present invention may have a near-neutral pi value, the present invention is of particular benefit for enzymatic liquid detergents with a pi of 7.5 or above, especially those incorporating bacterial pro teases of which the pH-optima lie in the range between 8.0 and 11.0, but it it 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 pro teases are the subtilisins which are obtained from particular strains of B. subtilis and B. licheniformis, such as the commercially available subtilisins Maxatase R (ox Gist-Brocades TV Deft, Holland) and Alkalis R (ox ova Industry A/S, Cozen-haven, Denmark).

As stated above, the present invention is of particular benefit for enzymatic liquid detergents incorporating enzymes with pH-activity and/or stability optima of above 8.0, such enzymes being commonly called high-alkaline enzymes.
Particularly suitable are pro teases obtained from strains of Bacillus, having maximum activity throughout the fringe of 8-12, developed and sold by Nova Incus-in So under the registered trade name of Espresso R
and Suaveness R.

123 I C 826 (R) The preparation of this enzyme and analogous enzymes is described in British Patent Specification Jo. 1,243,784 of Move.

High-alkaline amylases and cellulose can also be used, e.g. alpha-amylases obtained from a special strain of B. licheniformis, described in more detail in British Patent Specification Jo. 1,296,839 (ova).

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

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 active detergent material, which may be an alkali metal or alkanol amine soap or a C10-C24 fatty acid, including polymerized fatty acids, or an anionic, non ionic, cation-to, zwitterionic or amphoteric synthetic detergent mate-fiat, or mixtures of any of these.

Examples of anionic synthetic detergents are salts (in-eluding sodium, potassium, ammonium, and substituted am-minim salts, such as moo-, dip and triethanolamine salts) of Cg-C20 alkylbenzene sulphonates, C8-C22 prim many or secondary Al Kane sulphonates, C8-C24 olefin sulk founts, sulphonated polycarboxylic acids, prepared by sulphonation of the pyrolyzed product of alkaline earth metal citrates, e.g. as described in British Patent Specs ification No. 1,082,179, C8-C22 alkyd sulfites, C8-C24 alkylpolyglycolether sulfites (containing up to I

10 moles of ethylene oxide); further examples are de-scribed in "Surface Active Agents and Detergents" (Vol.
I and II) b Schwartz, Perry and Bench.

Examples of non ionic synthetic detergents are the con sensation products of ethylene oxide, propylene oxide and/or bottle neoxide with C8-C18 alkylphenols, C8-C18 primary or secondary aliphatic alcohols, C8-C18 fatty fatty acid asides; further examples of nonionics include tertiary amine oxides with one C8-C18 alkyd chain and two Clue alkyd chains. The above reference also describes further examples of nonionics.

The average number of molecules of ethylene oxide and/or propylene oxide present in the above nonionics 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 cat ionic detergents are the qua ternary ammonium compounds such as alkyldimethylammonium halogen ides, but such cationics are less preferred for inclusion in enzymatic detergent compositions.

US Examples of amphoteric or zwitterionic detergents are ~-alkylamino acids, sulphobetaines, condensation pro-ducts of fatty acids with protein hydrolysates, but owing to their relatively high costs they are usually used in combination with an anionic or a non ionic de-tergent. Mixtures of the various types of active deter-gents may also be used, and preference is given to mixtures of an anionic and a non ionic detergent active.
Soaps (in the form of their sodium, potassium, and sub-stituted ammonium salts) of fatty acids may Allah be US used, preferably in conjunction with an anionic and/or a non ionic synthetic detergent.
I

~2316~ C 826 (R) 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. avionics 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 1-40~ by weight.

The liquid compositions of the invention may further contain up to 60% of a suitable builder, such as sodium, potassium and ammonium or substituted ammonium pyre- and tripolyphosphates, -ethylenediamine tetraacetates, -no-trilotriacetates, -etherpolycarboxylates, -citrates, -carbonates, -orthophosphates, zealots, carboxymethyl-oxysuccinate, etc. Particularly preferred are the polyphos-lo plate builder salts, nitrilotriacetates, citrates, zeolites,and mixtures thereof. In general the builders are present in an amount of 1-60, preferably 5-50~, and particularly preferably 5-30% by weight of the final composition.

The amount of water present in the detergent compost-lions 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 brighter news, suds depressants such as silicones, germicides, anti-tarnishing agents, pacifiers, fabric softening agents, oxygen-liberating bleaches such as hydrogen peroxide, sodium perorate or per carbonate, dispraise-phthalic android, with or without bleach precursors, buffers and the like. When the composition contains a builder, it may sometimes be advantageous to include a suspension stabilizer in the composition to provide a satisfactory phase-stability. Such stabilizers include natural or synthetic polymers.

~31652 C 826 (R) Suitable examples of such suspension stabilizers are polyacrylates, copolymer~ of malefic android and ethyl-one or vinylmethylether, and polymers of acrylic acid, cross-linked with not more than 10% of a vinyl group containing cross-linkinq agent, e.g. polymers of acrylic acid, cross-linked with about 1% of a polyallyl ether of sucrose having an average of about 5.8 alkylgroups for each sucrose molecule. Examples of the latter are come Marshall available products, available unsex the no-Jo to sistered trade name of Carbopol of BY Goodrich Co.
Ltd.

In general, if a suspension stabilizer is required, it will be included in an amount of 0.1-2, usually 0.25-1 by weight of the final composition.

The invention will now be further illustrated by way of Example. In the examples, all the percentages are per-cent ages by weight of the final composition.
The pi of the final composition is near neutral, prefer-ably 7.5 or higher and is, if necessary, buffered to a value within that range by addition of a suitable buffer system. The pi of the wash liquor, when using the combo-session, is about 1 pi unit higher than the above violist an in-use concentration of about 1%.
I

~;~3165~, I

The following composition was prepared :
% by weight 5 Sodium dodecylbenzene sulphonate 5 C13-C15 linear primary alcohol condensed with 7 moles of ethylene oxide, which is a mixture of ethylene and 2 propylene oxide in a weight ratio of 92:8 10 Pentasodium triphosphate (an hydrous) 21 Sodium carboxymethyl cellulose 0.2 Carbopol (R) 941 (a polymer of acrylic 0.4 acid cross linked with about 1% of a polyp alkylether of sucrose having an average of 15 about 5.8 alkyd groups for each sucrose molecule) Fluoresce 0.1 Alkalis (R) marumes (activity 1.5 Arson unit/g) 0~7 20 Enzyme stabilizer or dicarboxylic acid x Borax y Sodium sulfite (an hydrous) z Water to 100.0 pi 7.5 x, y and z were varied, yielding a series of compost-lions 1-5.

The products were stored at 37C and the residual enzymatic activity (RAY) was determined at weekly inter-vets.

The following results were obtained:

Composition 1 : x = I Succinic acid RAY after y = 3.5% 8 weeks:
z = 8.0% 100%
I

C 826 (R) lZ31~

The same composition, but with I glycerol instead of succinic acid, had an RAY after 8 weeks of 80%.
m e system, where y c z = I had an RAY of 36~ after 1 week, and when x = z = 0%, an RAY of I after 1 week.

Composition 2 : x = 5% Succinic acid RAY after Y = 3-5~ 4 weeks:
z = 0 45%.

The same composition, but with I glycerol instead of succinic acid, had an I after 4 weeks of 27%.

The same composition, but with 5% adipic or glutaric acid instead of succinic acid, had an RAY after one week of 40%.
(The glutaric acid was added as glutaric acid android).

Composition 3 : x = 2% or 5% RAY after 4 weeks = 100 y = O
z = 8%
Composition 4 : x = 1% RAY after 4 weeks = 75%
y = O
z = 8%

For comparison, the same products but with 2.5 or 5 glycerol instead of succinic acid and 7.5% sodium sulfite:
x = 2.5 or 5 y = O

2 = 7.5 had an RAY after 4 weeks of 60%; the same composition but with only 7.5% sulfite:
x = O
y = O
z - 7.5 had an RAY of 32% after 1 week.

~3~6~ C 826 (~) Composition 5 : x = 5% of saccharin acid RAY after -y = 3,5% 8 weeks:
z = 8% 80%

S The same composition, but with I of glycerol instead of saccharin acid, had an I after 8 weeks of 80~.

Composition 6: x = 5% of Masonic acid RAY after -y = 3,5% 4 weeks:
Z = 0 44%-Composition 7 : x = I malefic acid RAY after y = 3.5% 4 weeks:
z = 0 46~.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An aqueous, enzymatic liquid detergent compo-sition comprising, in an aqueous liquid medium, as essen-tial ingredients, from 1-60% by weight of an active det-ergent material selected from the group consisting of soap, anionic, nonionic, cationic, zwitterionic and amph-oteric surfactants and mixtures thereof, from 1-60% by weight of a detergent builder, from 0.001-10% by weight of bacterial or fungal enzymes and a stabilizing system for said enzymes, wherein the stabilizing system con-sisting essentially of a mixture of (A) an inorganic compound selected from the group consisting of boric acid, boric oxide, alkalimetal bor-ate, a reducing alkalimetal salt having an oxygenated sulphur anion SaOb, in which a and b are whole numbers from 1 to 8, and mixtures thereof, and (B) a dicarboxylic acid of the general formula COOH-(CHOH)a-(CH2)b-(CHOH)c-(CH2)d-COOH
in which a, b, c and d are whole numbers from 0-4, the sum of a, b, c and d being from 0-4, whereby, when a=c=0 and b=c=1, the corresponding dicarboxylic acid may also be unsaturated, or the alkalimetal, ammonium, alkanola-mine or alkaline earth metal salts thereof, whereby the amount of (A) is from 1-15% by weight for the boron com-pounds and from 2-20% by weight for the reducing alkali-metal salt and the amount of (B) is from 0.5-15% by weight.

2. A composition according to claim 1, wherein the amount of (A) is from 3-10% by weight for the boron comp-ound or 5-15% by weight for the reducing alkalimetal salt and the amount of (B) is from 2-10% by weight.

3. A composition according to claim 1, wherein (A) consists of borax, sodium sulphite or a mixture thereof and (B) consists of succinic or saccharic acid.

4. A composition according to claim 1, having a pH
of 7.5 or above, and comprising 5-25% by weight of a mix-ture of an anionic and a nonionic synthetic detergent in a weight ratio of 6:1 to 1:6, 5-30% of a polyphosphate builder salt, 0.01 to 5% by weight of proteolytic or amylolytic enzymes having a pH-optimum above 8, and an enzyme stab-ilizing system consisting of 3-10% by weight of borax,

5-15% by weight of sodium sulphite and 2-10% by weight of disodiumsuccinate.