CA1092036A

CA1092036A - Enzymatic liquid detergent compositions

Info

Publication number: CA1092036A
Application number: CA289,879A
Authority: CA
Inventors: Jiri Hora; Gerardus A.A. Kivits
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 1976-11-01
Filing date: 1977-10-31
Publication date: 1980-12-23
Also published as: CH630406A5; ATA776477A; DE2748211A1; NL7711925A; LU78424A1; SE431558B; FR2369338A1; FI61715C; AT365229B; BE860374A; PT67225A; DK146910C; PT67225B; FI61715B; SE7712284L; AU3005177A; JPS5357209A; ZA776455B; FR2369338B1; IT1093027B

Abstract

Abstract of the Disclosure The storage-stability of aqueous enzymatic compositions, particularly aqueous enzymatic liquid detergent compositions, is improved by the inclusion therein of a stabilizing system comprising a polyhydroxy compound such as sorbitol, glycerol, ethyleneglycol and boric acid or a boron-equivalent thereof, in a weight ratio of less than 1.

Description

~9Z~36 C 546 (R) The present invention relates to an enzymatic liquid composition and more particularly to an enzymatic liquid detergent composition with an improved storage stability.
Liquid detergent compositions are well known in the art and, after the revival of interest in enzymes for inclusion in detergent compositions, several proposals have been made in the art for enzymatic liquid detergent compositions.
Despite khese proposals, such enzymatic liquid detergent compositions have not been put on the market to any sig-nificant extent, primarily because of severe instability problems incurred with the incorporation of enzymes in liquid detergent compositions. This problem is well recog-nized in the art, and it has for instance been proposed to reduce the instability of enzymes in liquid detergent compositions by incorporating stabilizing systems in such compositions.
Thus, for example, it has been proposed in Japanese patent application 47/35,192, laid open to public inspection , on 24th November, 1972, to prepare liquid, stabilized ~ 20 enzyme preparations, including enzymatic liquid detergent rl, compositions, by incorporating therein a combination of polyalcohols and borax. According to the specification of said Japanese patent application, these polyalcohols, examples of which are sorb1tol and glycerol, are used in an amount of at least 5% by weight of the final composition, preferably 10-30% by weight. The borax is used in at least 20%~ preferably 50-100% by weight of the polyalcohol. The weight ratio of polyalcohol to borax in the composition ;

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should therefore be equal to or greater than 1.
The compositions according to this prior proposal have furthermore, ashasbeen experimentallydetermined by a repeat of Example I, a p~-value in the range of 3.9 to 7.4.
It has now been found that the storage stability of enzymatic liquid detergent compositions with a pH-value of above 7.5, preferably between 8.5 and 11.0 (at 25C) can be significantly improved by the inclusion bherein of a sta- ~-bilizing system comprising one or more polyhydroxy compounds, which will be defined more specifically hereafter, and boric acid or a boron-equivalent thereof, the weight ratio of the polyhydroxy compounds to the boric acid or equivalent there-,~ of being sma~ler than l(calculated on the basis ofbora~. In comparison with combinàtions according to the above Japanese patent application, the systems of the present invention ;; demonstratea significantly improved enzyme stabillzing effect.
` The polyhydroxy compounds for use in the present in-vention contain only C-, H- and O-atoms. They are free from other (functional) substituting atoms such as N-, S- and the like. The polyhydroxy compounds should contain at least 2 hydroxy groups, and may contain even up to 6 hydroxy groups. Typical examples of polyhydroxy compounds particu-larly suitable for use in the present invention are diols such as 1,2-propanediol, ethyleneglycol, erythritan, poly-ols such as glycerol, sorbitol, and mannitol.
In general, the polyhydroxy compound is present in an amount of at least 4% by weight of the final composi-tion, up to 25% by weight. Preferably the amount ranges .,, ~, .

. . . . . . .. . . . . .

C 546 (R) ~092~36 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 poly-hydroxy compound, such as sodi~lm, ortho-, meta- and pyroborates, is used in an amount such that the weight ratio of the polyhydroxy co~pound to the boron compound is less than l(calculated onthe basis ofbora~.This means thatthe boron compound isused in an amount of more than I00% ofthe amount of the polyhydroxy compound. ~enerally the amount varies from ~100-200% by weight, and preferably from ~100-160% by weight of the polyhydroxy compound.
The weight ratio of polyhydroxy compound to the boric acid or equivalent is smaller than 1, generally from 0.5 up to just below 1.
The enzymatic liquid compositions in whichthe stabilizing systems ofthe invention are incorporated can be aqueous liquid systems, e.g.simple solutions,but they are-preferably aqueous liquid detergent compositions comprising as essential ingredients enzymes, active detergents and water, the pH being above 7.5, preferab~ between ~.5 and 11.0, or being adjusted thereto by proper means.
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 vege-table, animal, bacterialg fungal and yeast-origin. However, their choice is governed by several factors such as pH-activity and/or stability optima, thermostability, stabili-ty 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.
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: . '. ' '' ' ~ C 5l~6 (R) 1~9Z~36 The present invention is of particular benefit for enzymatic liquid detergents incorporating bacterial proteases of which the pH-optima lie in the range between 8.o 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 ~ (ex Gist-Brocades N.V., Delft, Hol-land) and Alcalase ~ (ex Novo Industri A/S, Copenhagen, Denmark). :
As stated above, the present invention is of particular benefit for enzymatic liquid detergents incorporating en-zymes with pH-activity and/or stability optima of above 8.o, such as enzymes also commonly called high-alkaline ,~ enzymes.
Particularly suitable is a protease, obtained from a strain of Bacillus, having maximum activity throughout the pH-range of 8-12, developed and sold by Novo Industri A/S
under the registered trade name Esperase ~ . The prepara-tion of this enzyme and analogous enzymes is described in British patent specification 1,243,784 of Novo.
High-alkaline a~ylases and cellulases can also be used, e.g. ~-amylases obtained from a special strain of B. licheniformis, described in more detail in British ; patent specification 1,296,839 (Novo).

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~92~36 C 546 (R) The amount of enzymes present in the liquid composition may vary from D.001 to 10% by weight,and preferably from 0.01 to 5% by weight.
The liquid detergent compositions of the invention fur-thermore comprise as essential ingredient an active detergent material, which maybe an alkali metalor alkanol amine soap o~
a C1o-C24 fatty acid, including~olymerized fatty acids or an anionic, nonionic, cationic, zwitterionic or amphoteric synthetic detergent material,or mixtures of any of these.
Examples of anionic synthetic deter~ents are salts (including sodium, potassium, ammonium, and substituted ammonium salts such as mono-, di- and triethanolamine salts) of Cg-C20 alkylbenzenesulphonates, C8-C22 primary or second-ary alkanesulphonates, C8-C24 olefinsulphonates, sulphonated polycarboxylic acids, prepared by sulphonation of the pyro-lYzed product of alkaline earth metal citrates, e.g. as described in British patent specification 1,082,179, C8-C22 alkylsulphates, C8-C24 alkylpolyglycolethersulphates (containing up to 10 moles of ethylene oxides); further examples are described in "Surface Active Agents and De-tergents" (Vol. I and II) by Schwartz, Perry and Berch.
Examples of nonionic synthetlc detergents are the con-densation products of ethylene oxide, propylene oxide and/or butyleneoxide with C8-C18 alkylphenols, C8 C18prlmary or sec-ondary aliphatic alcohols,C8-C18 fatty acid amides; further ex-amples of nonionics include tertiary amine oxides with one C8-C18 alkyl chain and two C1 3 alkyl chains. The above reference also describes further examples of nonionics.
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~9%036 C 546 (R) The average number of moles 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 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 com- !' bination with an 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 triethanolamine salts) of Clo-C24 fatty acids, as well as of polymerized fatty acids, may also be used,preferably in conjunction with an anionic and/or a nonionic synthetic detergent, and may exert a beneficial influence on the foaming behaviour of the final composition.
The amount of the active detergent material varies from 10 to 60%; when mixtures of e.g. anionics and non-ionics are used the relative weight ratio varies from 1:1 to 1:10. When a soap is also incorporated, the amount there-of is from 1-40% by weight.
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,, , l~Z036 C 546 (R) Although the liquids may contain up to 40% of a suitable builder, such as sodium, potassium and ammonium or substituted ammonium pyro- and tripolyphosphates, nitrilotriacetates, etherpolycarboxylates, citrates, carbonates, orthophosphates, polyelectrolytes such as polyvinylmethylether/maleic anhy-dride copolymers and so on, the present invention is of particular benefit for use in unbuilt liquid detergents.
` The amount of water present in the detergent compositions of the invention varies from 5 to 70% by weight.
Other conventional materials may als~o be present in the liquid detergent compositions of the invention, for example soil-suspending agents, hydrotropes, corrosion in-hibitors, dyes, perfumes, silicates, optical brighteners, suds boosters, suds depressants, germicides, anti-tarnish~
ing agents, opacifiers, fabric-softening agents, oxygen-liberating bleaches such as sodium perborate or percar-bonate with or without bleach precursors, buffers and the like.
The pH of the final composition is higher than 7.5 and should preferably lie within the range of 8.5 to 11.0, and is, if necessary, buffered to a value within that range by addition of a suitable buffer system (e.g.
with dimethylglycine).
The invention will now be further illustrated by way of Example. In the Examples the percentages are by weight. In the Examples, the extension of the enzyme . .
half-life time was determined in the following way:
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~ 9Z~36 C 5L~6 (R) .
A continuously withdrawn sample from a solution to be tested was continuously diluted (1:200) and continuously assayed on enzymatic activity (for proteolytic activity casein was used as a substrate). The logarithms of the -residual activity were plotted against the time, and the ~irst order rate constant K1 was computed.
The enzyme half-life time extension factor Ft is defined as:
~t= K1 (without stabilizing system) = ty/2 (with ~tabilizing system) .
K1~(with stabilizing system) ty/2 (without stabilizing system) ty/2 = time, at which the enzymatic activity y is half the initial enzymatic activity.
Example I
In this example, aqueous systems containing a bacterial protease, Alcalase ~ ex Novo were tested. These aqueous systems contained per litre:
0.2 Molar pentasodium tripolyphosphate 0.12 Molar dimethylglycine ` 1.7 g Alcalase ~ (activity 10.6 AU/g).
The pH of the solution was 10, and the temperature 57C. The rates of loss of activity of the enzyme were ~;
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measured in this system with and without the stabilizing . ~ . .
systems as indicated hereunder, and the enzyme half-life ` time extension factor ~las determined. The following '~ 25 results were obtained.

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~ -~ C 546 (R) 1~9Z0~6 No StabilizinF s~stem A~ounts Ratio -Ft ~ompound (P) Borax (B) - --- B pvalue _ .
~ ethyleneglycol ~ 10 15.49.649 a6.7 2 " + 6 9.2 0.6528.3

3 " _ 10 _ _ 1.9

4 glycerol ~ 10 10.3 0.97014.7 " _ 10 _ _ 1.8 6 1,2-propanediol + 6 7-5 o.8 6.7 7 sorbitol + 10 10.5' 0.952 3-9 8 " + 10 5.2 1.9232.6 9 " _ 10 _ _ 1.7 mannitol + 10 10.5 0.9523.2 11 " + 10 5.2 1.9232.3 12 " _ 10 I _ 1.8 These results show the increased Ft-valu~es obtained with the stabilizing systems of the invention. Tes~;sNos 8 and 11 are not according to the invention, (- ratio ~1), and show that with these ratios significa~tly reduced Ft-values are obtained, in comparison with - ratios ~1. Tests Nos 7-9 and 10-12 show that a reducing - ratio gives better Ft-values, in contrast to the prior art which prescribes the - ratio to have to be ~1. With 2%,4%, 8% and 9.45% borax only, (no polyhydroxy compound added), the following Ft-values were obtained: 1.0, 1.3, 1.8 and 2.4.
Example II
In this series of experiments, a bacterial protease - 10 -~ ' .;~,. .

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"Esperase" ~ ex Novo (activity 41.5 KNPU/g) was used. The aqueous ~ystem was identical to that of Example I, but the temperature was now 60C. With 4% erythritan and 7.4%
borax (B~- 54) a Ft of 2.5 was obtained.
Example III
In a manner analogous to that of Example I, systems with a bacterial ~-amylase (Thermamyl~) were tested. The aqueous system contained per litre:
0.12 M. pentasodium tripolyphosphate 1 o b .1 M. glycine 0.5 g Thermamyl (activity 450 KNU/g).
The pH was 9.95, and the temperature 59.3C.Wlth a -~
stabilizing system containing 6% ethyleneglycol ~ 9.2%
. . .: .
: borax (B ratio 0.65), an ~t-value of 2.2 was obtained.

` 15 Example I~
Example I was repeated with a stabiliæing system containing 10% glycerol and varying amounts of borax. The following results were obtained:
glycerol borax (%) P/B ratio ~t a)10% throughout 14 0.71 11.6 b) 12 o.83 12.8 c) 11 0.91 14.1 d) 10.6 0.94 14.2 `' e) 10.35 0.97 14.7 ' 25 f) 10 1.0 10.0 ;; g) 8 1.25 6.8 . h) 6.25 1.6 4.7 " i) 5 2 3.4 j) 2.5 4 2.3 , k) 0 - 1.8 , , .. ~ . - , , : . . . .
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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 composition with improved storage-stability, said composition comprising a stabilizing system comprising a) 4-25% by weight of the final composition of one or more polyhydroxy compounds only containing C-, H-and O-atoms, and containing 2-6 hydroxy groups;
b) boric acid or a boron-equivalent thereof, capable of reacting with the polyhydroxy compounds, the weight ratio of a:b being smaller than 1, said composition having a pH of 7.5-11,0.

2. A composition according to claim 1, wherein the weight ratio of a:b ranges from 0-5 to just below 1.

3. A composition according to claim 1, wherein the poly-hydroxy compound is 1,2-propanediol, ethyleneglycol, erythritan, glycerol, sorbitol or mannitol or a mixture thereof.

4. A composition according to claim 1, wherein the boron-equivalent of boric acid is boric oxide, borax or an alkalimetal ortho-, meta- or pyroborate.

5. A composition according to claim 1, wherein the polyhydroxy compound is present in an amount of 5-15% by weight of the final composition.

6. A composition according to claim 1, said composition having a pH of 8.5-11Ø

7. A composition according to claim 1, said composition comprising from 0.001-10% by weight of the final composition of proleolytic, amylolytic or cellulolytic enzymes or mixtures thereof, from 10-60% by weight of an active detergent material, and from 5-70% by weight of water.

8. A composition according to claim 1, comprising a bacterial proteolytic enzyme having a pH optimum of between 8 and 12.