NO172593B - ALKALIC WHITING TOUCH DETERGENTS CONTAINING PEROXID BLADE AND PEROXID BLADE PRESENT - Google Patents

Description

This invention relates to laundry detergent compositions. More particularly, it relates to an alkaline laundry detergent composition comprising a peroxide compound, a peroxyacid bleach precursor and enzymes.

It is well known that active oxygen-releasing peroxide compounds are effective bleaching agents. These compounds are often incorporated into detergent mixtures for stain and dirt removal. However, they have an important limitation: the activity is extremely temperature dependent. Thus, active oxygen-releasing bleaches are essentially only practically applicable when the bleach solution is heated to above 60°C. At a bleach solution temperature of approx. 60°C, very large amounts of the active oxygen-releasing compounds must be added to achieve a bleaching effect. This is both economically and practically disadvantageous. As the bleach solution temperature is lowered below 60°C, peroxide compounds, e.g. sodium perborate, ineffective, regardless of the level of peroxide compound added to the system. The temperature dependence of peroxide compounds is significant because such bleach compounds are usually used as a detergent auxiliary substance in textile washing processes where an automatic household washing machine is used which operates at washing water temperatures of less than 60°C.

Such washing temperatures are used for textile protection and energy reasons. Consequently, there has developed a continuing need for substances which make peroxide compound bleaches more effective at bleach solution temperatures below 60°C. These substances are usually referred to in the field as bleach precursors, promoters or activators.

The precursor is typically a reactive compound of the N-acyl or O-acyl type such as a carboxylic acid ester which in alkaline solution containing a source of hydrogen peroxide, e.g. a persalt, such as sodium perborate, will form the corresponding peroxyacid, which is more reactive than peroxide compounds alone. The reaction involves nucleophilic substitution of the precursor molecule by perhydroxide anions (H000 and proceeds more easily with precursors with good leaving groups. This reaction is often referred to as perhydrolysis. Numerous substances have been proposed in the field of

effective bleach precursors, promoters or activators,

As described in a series of articles by Allan H. Gilbert in Detergent Age, June 1967, pages 18-20, July 1967, pages 30-33 and August 1967, pages 26-27 and 67; and further in British Patents 836,988, 907,356, 1,003,310 and 1,519,351; German Patent 3,337,921, European Patent A 0,185,522, European Patent A 0,174,132, European Patent B 0,120,591 and US Patents 4,412,934 and 4,675,393.

The precursor is normally also a hydrolyzable material which

may react with moisture and alkaline components in the detergent mixture during storage, forming non-reactive products. This reaction, referred to as hydrolysis, causes loss of precursor during storage when incorporated into detergent compositions,

and the extent of it is highly dependent on the ease with which the precursor undergoes the hydrolysis reaction.

Various aids have been proposed in the field to protect the precursor from the aqueous and alkaline components in the detergent mixture during storage. However, it should be clear that the less stable the precursor is to hydrolysis, the more difficult it will be to achieve adequate protection.

It is believed that this may be a reason why only a few of

the large number of proposed compounds have found commercial use, among which N,N,N',N'-tetraacetylethylenediamine (TAED), belonging to the type of N-acyl precursors, is the most used in practice.

However, one disadvantage of TAED is the slowness of the peroxyacid release from the reaction in terms of the peroxide compound's release of hydrogen peroxide, such as sodium perborate, sodium percarbonate, sodium persilicate, urea peroxide and the like, resulting in a non-optimal bleaching effect. TAED can thus be classified as a slow-acting precursor, which can be incorporated into enzymatic alkaline detergent mixtures without unnecessary stability problems.

Another disadvantage of TAED is that its solubility in water is quite poor, i.e. somewhere in the region of around 1%, which is another reason for the non-optimal bleaching performance of TAED/hydrogen peroxide systems.

With the tendency towards even lower laundry temperatures, to e.g.

40°C and below, there is an incentive to improve the bleaching performance of TAED/peroxide compound systems. One possibility is to replace TAED with a reactive precursor, such as, for example, sodium p-acetoxybenzenesulfonate as described in British Patent 846,798.

However, a disadvantage of such more reactive precursors is that they tend to (per)hydrolyse faster than tetraacetyl-ethylenediamine (TAED), and consequently they pose a more serious decomposition problem during storage.

Another disadvantage of more reactive precursors is that they tend to attack enzymes more quickly, especially "proteolytic enzymes", which as a class are a significant component in the bulk of common household laundry detergent compositions.

Consequently, there has developed a constant need for possibly new and better substances that make peroxide compound bleaches more effective at bleach solution temperatures in the range from ambient temperature to approx. 40°C, without the above-mentioned shortcomings and disadvantages.

It has now been found that specific carboxylic acid esters as defined below are more reactive bleach precursors than TAED, and yet they are surprisingly more stable to hydrolysis than sodium p-acetoxybenzenesulfonate and more enzyme friendly, making them more suitable for use in enzymatic alkaline cloth-detergent mixtures.

The invention therefore provides an improved alkaline laundry detergent mixture comprising a surface-active material, detergency builders, a peroxide compound bleach, a peroxy acid bleach precursor and a proteolytic enzyme, characterized in that the peroxy acid bleach precursor is a carboxylic acid ester with the following specific structural formulas:

where M is alkali metal.

The alkaline laundry detergent mixtures according to the invention which comprise the peroxy acid bleach precursor described herein will advantageously have a pH of 8.5-10.5 in a 2-5 g/l solution.

The use of these carboxylic acid esters in bactericidal detergent mixtures is described in German Patent Application No. 2 701 133. However, it cannot be expected that these specific esters are effective bleach precursors that can be used and have excellent stability in enzymatic alkaline laundry detergent mixtures together with a peroxide compound bleach that provides improved bleaching performance for clothes in the lower washing temperature range of, from ambient temperature to approx. 40°C.

The compounds used in the invention are much more reactive than TAED and are surprisingly stable when stored both alone and in admixture with additional ingredients in alkaline laundry detergent mixtures.

The following compounds are illustrative of precursors within the present invention: sodium 3-benzoyloxybenzoate and

. sodium 4-benzoyloxybenzoate.

Hydrogen peroxide sources are well known in the art. They include the alkali metal peroxides, organic peroxide bleach compounds such as urea peroxide, and inorganic persalt bleach compounds such as the alkali metal perborates, percarbonates, perphosphates and persulfates. Mixtures of two or more such compounds may also be suitable. Particularly preferred is sodium perborate tetrahydrate and especially sodium perborate monohydrate. Sodium perborate monohydrate is preferred because it has excellent storage stability while also dissolving very rapidly in aqueous bleach solutions. Rapid dissolution is believed to enable the formation of higher levels of percarboxylic acid which would improve surface bleaching performance.

The molar ratio between hydrogen peroxide (or a peroxide compound that forms the equivalent amount of H 2 O 2 ) and precursor will typically be in the range from 0.5:1 to about 20:1, preferably from 1:1 to 15:1, most preferably from 2:1 to 10:1.

A detergent preparation according to the invention which contains a bleaching agent system consisting of an active oxygen-releasing material and the specific carboxylic acid ester as defined herein will, in addition to surface-active materials, detergency builders and enzymes, usually also contain other known components in such preparations.

In the preparation according to the invention, the peroxyacid bleach precursor can be present at a level in the range from approx. 0.1 to 20% by weight, preferably from 0.5 to 10% by weight, especially from 1 to 7.5% by weight, together with a peroxide-bleach compound, e.g. sodium perborate mono- or -tetrahydrate, and the amount of this is usually within the range from approx. 2 to 40% by weight, preferably from 4 to 30% by weight, especially from 10 to 25% by weight.

The surface-active material may be of natural origin, such as soap, or it may be a synthetic material selected from anionic, non-ionic, amphoteric, zwitterionic and cationically active materials and mixtures thereof. Many suitable active materials are commercially available and are fully described in the literature, for example in "Surface Active Agents and Detergents", Volumes I and II, by Schwartz, Perry and Berch. The total level of the surface active material can be in the range up to 50% by weight, preferably from 1 to 40% by weight, based on the detergent composition, most preferably 4-25% by weight.

Synthetic, anionic surface-active materials are usually water-soluble alkali metal salts of organic sulfates and sulfonates with alkyl radicals containing from approx. 8 to approx. 22 carbon atoms, the term alkyl as used includes the alkyl portion of higher aryl radicals.

Examples of suitable synthetic anionic detergent compounds are sodium and ammonium alkyl sulphates, especially those obtained by sulphating higher (C8-C18) alcohols produced, for example, from tallow or coconut oil; sodium and ammonium alkyl-(C9-C20)-benzenesulfonates, especially straight-chain secondary sodium alkyl-(C10-C15)-benzenesulfonates; sodium alkylglyceryl ether sulfates, especially such esters of the higher alcohols derived from tallow or coconut oil and synthetic alcohols derived from petroleum; sodium coconut oil fatty acid monoglyceride sulfates and sulfonates; sodium and ammonium salts of sulfuric acid esters of reaction products of higher (C9-C18)-fat alcohol alkylene oxide, especially ethylene oxide; the reaction products of fatty acids such as coconut fatty acids esterified with isethionic acid and neutralized with sodium hydroxide; sodium and ammonium salts of fatty acid amides of methyl taurine; alkane monosulfonates such as those obtained by reacting alpha-olefins (C8-C20) with sodium bisulfite and those obtained by reacting paraffins with SO 2 and Cl 2 and then hydrolyzing with a base to form a random sulfonate; sodium and ammonium C7-C12 dialkyl sulfosuccinates; and olefin sulphonates, which term is used to describe the material produced by reaction of olefins, especially C10-C20-alpha-olefins, with SO3 and then neutralization and hydrolysis of the reaction product. The preferred anionic detergent compounds are sodium (C 1 -C 15 ) alkylbenzene sulfonates, sodium (<C>16<-C>18 ) alkyl sulfates and sodium (C 16 -<C>18 ) alkyl ether sulfates.

Examples of suitable non-ionic surface-active compounds which can be used, preferably together with the anionic surface-active compounds, include in particular the products of the reaction between alkylene oxides, usually ethylene oxide, and alkyl-(C6-C22) - phenols, usually 5-25 EO, i.e. 5-25 units of ethylene oxides per molecule; the condensation products of the reaction between aliphatic (C8-C18) primary or secondary straight-chain or branched alcohols and ethylene oxide, usually 6-30 EO, and products produced by the condensation of ethylene oxide with the products of the reaction between propylene oxide and ethylenediamine. Other so-called nonionic surfactants include alkyl polyglycosides, long-chain tert-amine oxides, long-chain tert-phosphine oxides and dialkyl sulfoxides.

Certain amounts of amphoteric or zwitterionic surface-active compounds can also be used in the detergent mixtures according to the invention, but this is normally not desirable due to the relatively high costs associated with them. If any amphoteric or zwitterionic detergent compounds are used, it is usually in small amounts in detergent compositions based on the much more commonly used synthetic anionic and non-ionic active materials.

As indicated above, soaps can also be incorporated into the detergent compositions according to the invention, preferably at a level of less than 25% by weight. They are particularly suitable at low levels in binary (soap/anionic) or ternary mixtures together with nonionic or mixed synthetic, anionic and nonionic compounds. Soaps used are preferably the sodium or, less desirable, the potassium salts of saturated or unsaturated C10-C24 fatty acids or mixtures thereof. The quantity of such soaps can be varied between approx. 0.5 and approx. 25% by weight, with lower amounts of from approx. 0.5 to approx. 5% is usually sufficient for foam control. Amounts of soap between approx. 2 and approx. 20%, especially between approx. 5 and approx. 10%, is used to achieve a beneficial effect on washing ability. This is particularly valuable in detergent mixtures used in hard water when the soap acts as an additional builder.

The detergent mixtures according to the invention will normally also contain a detergency builder. Building materials can be selected from 1) calcium sequestration materials, 2) precipitation materials, 3) calcium ion exchange materials and 4) mixtures of these.

Examples of calcium sequestering builders include alkali metal polyphosphates, such as sodium tripolyphosphate; nitrile triacetic acid and its water-soluble salts; the alkali metal salts of carboxymethyloxysuccinic acid, ethylenediaminetetraacetic acid, oxysuccinic acid, mellitic acid, benzene polycarboxylic acids, citric acid; and polyacetal carboxylates as described in US Patents 4,144,226 and 4,146,495.

Examples of precipitating building materials include sodium mortophosphate, sodium carbonate and long-chain fatty acid soaps.

Examples of calcium ion exchange building materials include the various types of water-insoluble crystalline or amorphous aluminum silicates, among which zeolites are the best known representatives.

The detergent mixtures according to the invention can in particular contain any of the organic or inorganic building materials, such as sodium or potassium tripolyphosphate, sodium or potassium pyrophosphate, sodium or potassium orthophosphate, sodium carbonate or sodium carbonate/calcite mixtures, the sodium salt of nitrile triacetic acid, sodium citrate, carboxymethylmalonate, carboxymethyloxysuccinate and the water-insoluble crystalline or amorphous aluminosilicate building materials, or mixtures thereof.

These building materials can be present at a level of, for example, from 5 to 80% by weight, preferably from 10 to 60% by weight.

The proteolytic enzymes suitable for use in the present invention are normally solid, catalytically active protein materials which degrade or change the protein types in stains when they are present as in fabric stains in a hydrolysis reaction. They may have any suitable origin, such as vegetable, animal, bacterial or yeast origin.

Proteolytic enzymes or proteases of different qualities and origins and with activity in different pH ranges from 4 to 12 are available and can be used in the detergent mixtures according to the present invention. Examples of suitable proteolytic enzymes are the subtilisins obtained from particular strains of B. subtilis and B. licheniformis, such as the commercially available subtilisins Maxatase<®>, supplied by Gist-Brocades N.V., Delft, Holland, and Alcalase<®>, supplied by Novo Industri A/S, Copenhagen, Denmark.

Particularly suitable is a protease obtained from a strain of Bacillus with maximum activity throughout the pH range 8-12, which is commercially available, e.g. from Novo Industri A/S under the registered trademarks Esperase<®> and Savinase<®>. The production of these and analogous enzymes is described in British patent 1,243,784.

Other examples of suitable proteases are pepsin, trypsin, chymotrypsin, collagenase, keratinase, elastase, papain, bromelain, carboxypeptidases A and B, aminopeptidase and aspergillopeptidases A and B.

The amount of proteolytic enzymes normally used in the detergent mixture according to the invention can be in the range from 0.001 to 10% by weight, preferably from 0.01 to 5% by weight, depending on their activity. They are usually incorporated in the form of granules, "prills" or "marums" in such a quantity that the final washing product has a proteolytic activity of from approx. 2 to 20 Anson units per kg end product.

Apart from the components already mentioned, the detergent mixtures according to the invention may contain any of the conventional additives in the quantities at which such materials are normally used in laundry detergent mixtures. Examples of these additives include foaming agents such as alkanolamides, especially the monoethanolamides derived from palm kernel fatty acids and coconut fatty acids, antifoaming agents such as alkyl phosphates and silicones, anti-redeposition agents such as sodium carboxymethyl cellulose and alkyl or substituted alkyl cellulose ethers; peroxide stabilizers such as ethylenediaminetetraacetic acid, ethylenediaminetetra(methylenephosphonic acid) and diethylenetriaminepenta(methylenephosphonic acid); fabric softeners including clays, inorganic salts such as sodium sulfate, and, usually present in very small amounts, fluorescent agents, perfumes, other enzymes such as cellulases, lipases and amylases, germicides and dyes.

Other suitable additives are polymeric materials, such as polyacrylic acid, polyethylene glycol and the copolymers of (meth)acrylic acid and maleic acid, which can also be incorporated to act as auxiliary builders together with any of the main detergency builders such as the polyphosphates, aluminum silicates and the like.

For stability improvement and handling improvement reasons, the bleach precursors will usually advantageously be presented in the form of particulate substances comprising the bleach precursor and a binder or an agglomerating agent. Many different methods for the production of such particulate precursor materials have been described in various patent literature documents such as e.g. in Canadian Patent 1 102 966, British Patent 1 561 333, US Patent 4 087 369, European Patent A 0 240 057, European Patent A 0 241 962, European Patent A 0 101 634 and European Patent A 0 062 523. Each of these methods can be selected and used for the bleach precursor used in the invention.

Particulate materials including such precursors as herein described are normally added to the spray-dried portion of the detergent mixture with the other dry mixture ingredients, such as enzymes, inorganic peroxygen bleaches and suds suppressors. However, it will be understood that the detergent mixture to which the particulate precursor materials are added can itself be made in many different ways, such as by dry mixing, agglomeration, extrusion, flake formation, etc.; such ways are well known to those skilled in the art and do not form part of the present invention.

In a specific embodiment according to the invention, the peroxy acid precursors are incorporated into so-called non-aqueous, liquid laundry detergent mixtures containing enzyme, together with a peroxide bleaching compound, e.g. sodium perborate, so that the products have an effective cleaning and stain removal capacity when it comes to clothes and textiles.

Non-aqueous liquid detergent compositions which include paste-like and jelly-like detergent compositions into which the precursor compounds can be incorporated are known in the art,

and various preparations have been proposed, e.g. in US Patents 2,864,770, 2,940,938, 4,772,412, 3,368,977, British Patent A 1,205,711, 1,270,040, 1,292,352, 1,370,377, 2,194,536, West German Patent A 2,233,771 and European patent A 0 028 849.

These are detergent compositions which normally comprise a non-aqueous, liquid medium with or without a solid phase dispersed in it. The non-aqueous liquid medium may be a liquid surfactant, preferably a liquid nonionic surfactant; a non-polar liquid medium, e.g. liquid paraffin; a polar solvent, e.g. polyols, such as glycerol, sorbitol, ethylene glycol, optionally mixed with monohydric low-molecular alcohols, e.g. ethanol or isopropanol; or mixtures thereof.

The solid phase can be builders, alkalis, abrasives, polymers, clays, other solid ionic surfactants, bleaches, enzymes, fluorescent agents and other common solid detergent ingredients.

EXAMPLE I

The hydrolysis of various bleach precursors was measured using the following technique.

1 gram of sodium lauryl sulfate and 2 grams of sodium metaborate tetrahydrate were dissolved in 1000 ml of double distilled deionized water; this solution was used in the reference cell of the spectrophotometer. Sufficient precursor was added to 800 ml of the stirred solution to obtain an optical density of

0.4-0.8, and the solution was passed through a flow cell in the spectrophotometer. The decomposition (hydrolysis) of the precursor was checked by measuring the decrease in optical density at the wavelength of maximum absorbance.

The following bleach precursors were used:

1) Sodium 1-benzoyloxybenzene-4-sulfonate (BOBS).

2) Sodium p-acetoxybenzenesulfonate (SABS).

3) Sodium 3-benzoyloxybenzoate (S-3-B0B).

4) Sodium 4-benzoyloxybenzoate (S-4-B0B). The results are listed in the table below:

The results confirm that the bleach precursors 3) and 4) used in the invention are more stable to hydrolysis than the reactive esters BOBS and SABS.

EXAMPLE II

The following granular detergent composition was prepared by spray drying an aqueous slurry:

To this base powder was added 15 parts of sodium perborate monohydrate, and an amount of precursor with a molar ratio between precursor and perborate of 1:9, and 1% by weight of a proteolytic enzyme (Savinase<®> T40 marumer).

Bleaching tests were carried out with the finished powder preparation using different precursors, in a Tergotometer heating wash to 40°C in 24°FH water at a dosage of 5 g/l. Tea-stained experimental garments were used as a bleaching control. The bleaching efficiencies were determined using an Elrepho reflectometer,

and the results, expressed as aR 460<*>, are shown in the following Table II.

These results show that both detergent mixtures according to the invention containing the precursors 1) S-4-BOB and 2) S-3-BOB are superior to TAED in removing tea stains from clothes at 40°C.

EXAMPLE III

Samples of the finished powder preparations according to Example II containing perborate, enzyme and unprotected precursors were stored in open ampoules at 25°C and 81% relative humidity for 7 days.

The enzyme activities were determined in the stored samples after

7 days and compared with newly prepared samples. The results presented in Table III as percent loss of enzyme activity were the average of duplicate storage experiments:

These experimental results show that the precursors used in the invention are even more compatible with the enzyme Savinase<®> T40 than TAED.

Claims (3)

1. Alkaline laundry detergent mixture comprising a surface-active material, detergency builders, a peroxide compound bleach, a peroxyacid bleach precursor and a proteolytic enzyme, characterized in that the peroxyacid bleach precursor is a carboxylic acid ester with the following specific structural formulas: where M is alkali metal. 2. Detergent mixture according to claim 1, characterized in that a solution thereof of 2-5 g/l has a pH of 8.5-10.5. 3. Detergent mixture according to any one of the above claims, characterized in that the detergent mixture is a non-aqueous, liquid detergent mixture.