NO822434L - Detergent additives. - Google Patents

Abstract

A ternary builder system for detergent compositions comprises 25 to 97% by weight of an aluminosilicate cation-exchange material such as Zeolite A and 3 to 75% by weight, in total, of ( i) a soap containing at least 60% by weight of saturated material, and (ii) nitrilotriacetic acid or a water-soluble salt thereof, at a (i):(ii) ratio of 10:1 to 1:10, the proportion of soap in the ternary mix being at least 12%. The builder mix is advantageously used in detergent compositions containing less than 10% inorganic phosphate, and gives good results in zero-phosphate compositions.

Description

The invention relates to additives for detergent mixtures, as well as detergent mixtures containing them. These products are specially, but not essentially, adapted for laundry. The invention relates more particularly to practically phosphate-free detergent mixtures.

Laundry preparations contain conventional phosphate builders, for example sodium tripolyphosphate. In some situations, it is believed that the use of phosphates in detergent mixtures can lead to environmental problems in waste water.

There is therefore a desire to reduce the phosphorus level, or to eliminate it completely in detergent mixtures.

Water-insoluble aluminosilicate ion exchange materials have been proposed as alternative builders to phosphates, see for example British Patent Nos. 1,473,201 and 1,473,202. However, it has been found in practice that these aluminosilicate materials, even in large quantities, have tend to be undesirably slow in their exchange of cations, especially at low temperatures, resulting in poor detergency. Consequently, it has been proposed to use supplementary water-soluble builders in combination with these aluminosilicates in order to raise the washability to an acceptable level. These supplemental builders are generally materials that are effective sequestering builders in their own right, such as alkali metal tripolyphosphates, nitrile triacetates, and poly-α-hydroxy acrylates. However, large quantities of these materials are not generally desirable in detergent mixtures for cost or environmental reasons.

We have now discovered that surprisingly good washability results. is achieved by using, in combination with an aluminosilicate builder, relatively small amounts of both a specific organic sequestering builder (nitrile triacetic acid or a salt thereof) and a specific organic precipitating builder (a def inert soap or soap mixture).. The detergency- results obtained with ternary systems of this type have surprisingly proven to be better than what would be expected from consideration of the results obtained using the corresponding binary aluminosilicate/sequestering agent and aluminosilicate/precipitating agent systems, so that reduced quantities of the supplementary builders can be used, which gives short savings in costs and environmental benefits.

It is known that the detergency-building properties of a lunt in no - silicates are improved by the addition of water-soluble complexing agents, for example sodium tripolyphosphate, This effect has been explained on the basis of the so-called "carrier molecule model", see for example P. Berth, J Am. Oil Chemists<1>Soc.,' 55., 52-53. (1978). The complexing agent has ability

to absorb multivalent water hardness ions (especially Ca +, but also o Mg 2+) from solid surfaces (such as the surface of a textile fiber). and passes them on to the aluminosilicatione exchanger after transport through the aqueous medium. The complexing agent forms a chelate complex with the hardness ion which dissociates on arrival at the surface of the aluminosilicate.

It is not easy to consider a similar mechanism with precipitation builders, for example soaps, since these remove hardness ions from the wash bath by the practically irreversible formation of a precipitation product (insoluble calcium or magnesium salt).

Thus, it is unexpected that the addition of a soap to an aluminosilicate/sequestrant system provides significant improvement in detergency building properties.

The present invention therefore provides, in a first aspect, a washing additive which generally consists essentially of: (a) from approx. 25 to approx. '97 weight of a crystalline or amorphous

aluminosilicate cation exchange material,.

(b) . from approx. 3 to approx. 7 5% by weight, total, of

(i) one or more water-soluble soaps of cio~C22-^ettsYrer'

since at least 60% by weight of the total soap is saturated material,

(ii) nitrile triacetic acid or a water-soluble salt thereof,

wherein the weight ratio between (i) and (ii) is from 1:10 to 10:1, and (i) is present in an amount of at least 12% by weight, preferably at least 15% by weight, based on the total weight of ( a) and (b).

Component (b)(ii) will hereinafter be referred to as

NTA.

Thus, the object of the invention is a ternary building system consisting of aluminosilicate, soap and NTA.

In British patent specification 1 498 492 and BRD patent specification

25 39 110 are obviously detergent mixtures, built with aluminosilicate and NTA, where the detergent active system includes soap. However, the soap is present only in small amounts.

European patent 38 591 discloses detergent compositions.which •

is built with aluminosilicate, where the detergents used include soaps of C^g-C^-unsaturated fatty acids. These soaps function in the mixtures as washing active agents, helping with dirt removal and cold water washability. The aluminosilicate. is said to help keep the unsaturated soap from forming an insoluble soap mass. Consequently, the unsaturated soaps do not function as builders by precipitating calcium from the washing bath as insoluble calcium soap. The soap compositions disclosed in European Patent 38,591 may contain some saturated soap, but only in small amounts so that the detergency activity of the preferred unsaturated materials is not impaired.

The unsaturated soaps that are. obvious in European patent.

38,591 are unsuitable for use in the mixtures according to the present invention, as their calcium salts are not sufficiently insoluble in water. The predominantly saturated soaps used according to the invention have, on the other hand, highly insoluble calcium salts. Calcium present in the washing bath is removed in the form of insoluble calcium soaps. The soaps themselves thus function as builders rather than as active detergents.

The soaps used in the mixtures according to the present invention consist of at least 60%, preferably at least. 80%, of saturated soaps. Advantageously, 100% saturated material can be used.

The soap preferably contains both longer-chain (C^g and higher) and shorter-chain (C^ and lower) material. The longer the chain, the greater the insolubility of the calcium salt, and the greater the effectiveness of the soap builder. However, soaps with a shorter chain length, although they form less insoluble calcium salts, can also be effective detergency builders due to their lower molecular weight and consequently greater weight efficiency. The shorter chain soaps are particularly valuable in low temperature washing conditions.

Shorter-chain soaps themselves (ie, generally the sodium salts) also have better solubility than the longer-chain materials, and the presence of some short-chain material along with longer-chain soaps can improve overall soap solubility.

In general, it contains the soap used in the washing additive

according to the invention, for efficient construction preferably at least 5% by weight, preferably at least 8%, of material with a chain length of C^g and higher. It can also be advantageous, from a solubility point of view, that the soap used in the washing additive

according to the invention contains at least 1%, preferably at least 3%, of material having a chain length of C, . and lower.

When predominantly longer-chain soaps are used in the laundry additive according to the invention, the soap or the mixture of soaps contains at least 60% by weight, preferably at least 80% by weight, of material having a chain length of C 2 g and higher. It is also advantageous, from a solubility point of view, that the soap in- holds at least 1%, preferably at least 3%, of material of chain length and lower. However, this is not essential for products intended for use in conventional medium or high temperature washing, where the solubility of the soap itself (sodium or other soluble salt) is not a problem.

Examples of such soaps include hardened tallow (67% C^g and higher) and hardened rapeseed (96.5%.C^g°9higher).

When predominantly shorter-chain soaps are used in the washing additive according to the invention, the soap or the mixture of soaps contains at least 60% by weight, preferably at least 70% by weight, of material with chain length C14 and lower. It preferably contains! also at least 5%, preferably at least 8%, of material with chain length c'l8 and higher. Such a product is particularly useful for lower-temperature washrooms where the solubility of the soap itself is important in determining good washability.

Examples of such soaps include coconut (82% C^4 and lower) and palm kernel (73.5% C14 and lower).

The following table shows the composition of the four soaps mentioned above:

These are of course only examples of the many soaps and soap mixtures that can be used in the washing additive according to the invention.

The washing additive according to the invention also includes a water-insoluble aluminosilicate cation exchange material. This is a crystalline or amorphous material with the general formula:

where Cat is a cation of valence n that is exchangeable with calcium (for example, Na<+> or K<+>); x is a number of 0.7-1.5;

y is a number of 1.3-4; and z is such that the content of bound water is 10-28% by weight.

Preferably, a crystalline material is used which can be described by the unit cell content:

where x and y are whole numbers of at least 6, the ratio between x and y being in the range from 1:1 to 1:2; and z is such that the bound water content is from 10 to 28% by weight.

The aluminosilicate preferably has a particle size of 0.1-100 ym, ideally between 0.1 and 10 ym, and an ion exchange capacity of at least 200 mg CaCO^pr. grams of aluminosilicate (anhydrous basis],

In a preferred embodiment, it is water-insoluble aluminosilicate. a crystalline material with the formula described by the unit T cell content:

where z is 20-30, preferably approx. 27.

An example of this material is the commercially available product known as Zeolite, type A, which is typically: and is also described by its unit-cell content:

The third component in the washing additive according to the invention is an organic sequestering builder, namely nitrile triacetic acid or a water-soluble salt thereof (NTA). This component can be represented by the following structural formula:

where X is hydrogen or a solubilizing cation. These compounds can further contain C-bonded substituents of an inert and non-toxic nature, for example alkyl, for example methyl or ethyl, or haloalkyl, for example chloromethyl. The nature of the said compounds is not particularly critical, with the implicit limitation that such substituents must be devoid of any tendency to adversely affect the desirable properties of NTA.

Preferred compounds falling within the scope of the above described definition and formula are nitrile triacetic acid and its alkali metal salts, especially trisodium nitrile triacetate monohydrate, tripotassium nitrile triacetate, disodium nitrile triacetate and dipotassium nitrile triacetate.

The soap and NTA together make up from approx. 3 to approx. 75% by weight of the builder mix (washing additive) according to the invention, preferably from approx. 10 to approx. 60% and especially from approx. 20 to approx. 50%, The ratio between soap and NTA is from 10:1 to 1:10, preferably from 3:1 to 1:3 and desirably from 3:1 to 1:1.

The washing additive according to the invention is an effective builder system which gives good washing performance results when it is incorporated together with detergent-active materials in a detergent mixture.

Accordingly, the invention provides, in another aspect, a detergent mixture comprising from approx. 3 to approx. 90% by weight

of at least one synthetic detergent-active material and from approx. 10 to approx. 97% by weight of a washing additive as previously defined.

The detergent mixture according to the invention contains from approx. 10 to approx. 97% by weight of the washing additive according to the invention, preferably from approx. 10 to approx. 80%, more preferably fira approx. 25 to approx. 70% and especially from approx. 28 to approx. 67%.

Since the washing additive contains from approx. 25 to approx. 97% by weight aluminosilicate, the aluminosilicate content in the detergent mixture can vary from approx. 2.5 to approx. 94%. An aluminosilicate content of from approx. 10 to approx. 60%, especially from approx. 17 to approx.

4 7%, preferred.

Likewise, the content of the specified organic builders (soap plus NTA) can vary from approx. 0.3 to approx. 73%, as an area of from approx. 5 to approx. 40%, especially from approx. 7 to approx. 27%, preferred. The preferred range for the content of the soap is from approx. 3 to approx. 20%, especially from approx. 5 to approx. 10%; for NTA, the preferred area is from approx. 1 to approx. 15%, especially

from approx. 2 to approx. 10%.

The detergent mixtures according to the invention are preferably generally substantially free of inorganic phosphate. This is highly desirable for environmental reasons as mentioned earlier. Products according to the invention which do not contain any inorganic phosphate have been shown to exhibit detergency properties comparable to those of sodium tripolyphosphate-based products.

However, if desired, the products can contain inorganic phosphorus. barrel, but if there is a question of avoiding the possible environmental effects of phosphate, then the level advantageously does not exceed 10% based on the whole product; levels below 5% and more particularly below 3% are of particular interest in this regard. Any phosphate that is present can, for example, be in the form

of alkali metal (preferably sodium) tripolyphosphate, -orthophosphate,

-pyrophosphate or polymeric phosphate.

The detergent mixture according to the invention can, if desired, contain other builders in addition to the specified ternary builder system according to the invention. As indicated earlier, these are preferably non-phosphate materials. Examples of suitable materials include the water-soluble salts of the following acids: ethylenediaminetetraacetic acid, polyacrylic acid, poly(a-hydroxyacrylic) acid, carboxymethyloxymalonic acid, carboxymethyloxysuccinic acid, oxydiacetic acid, oxysuccinic acid, citric acid, dipicolinic acid and many more. The polyacetal carboxylates disclosed in US Patents 4,144,126 and 4,146,495, and the oxidized polysaccharides disclosed in British Patents 1,330,121, 1,330,122 and 1,330,123 may also be used to advantage.

The detergent mixtures according to the invention necessarily include from approx. 3 to approx. 90% by weight, preferably from approx. 5 to approx. 40% by weight, preferably from approx. 10 to approx. 25% by weight, of a synthetic anionic, nonionic, amphoteric or zwitterionic detergent compound or mixture thereof. Many suitable detergent active compounds are commercially available and are fully described in the literature, for example in "Surface Active Agents and Detergents", Vols. I and II, by Schwartz, Perry and Berch.

The preferred washing compounds that can be used are synthetic anionic and nonionic compounds. The former are usually water-soluble alkali metal salts of organic sulfates and sulfonates which have alkyl radicals containing from approx. 8 to approx. 22 carbon atoms, the term alkyl being used to include the alkyl part in higher aryl radicals. Examples of suitable anionic washing compounds are sodium and potassium alkyl sulfates, especially those obtained by sulfation of higher (C8~ci8^~alcohols, for example produced from tallow or coconut oil; sodium and potassium alk<y>l(Cg- C20)benzenesulfonates, especially sodium linear-secondary-alkyl(ciq_C25^-benzenesulfonates; sodium alkyl-.glyceryl ether sulfates, especially such ethers of the higher alcohols derived from tallow or coconut oil and synthetic alcohols derived from petroleum; sodium coconut oil fatty acid- monoglyerides sulfates and sulfonates; sodium and potassium salts of sulfuric acid esters of higher (Cg-C-^g).-f one alcohol-alkylene oxide-, especially -ethylene oxide reaction products; the reaction products of such fatty acids as coconut fatty acids esterified with isethionic acid and neutralized with sodium hydroxide; sodium and potassium salts of fatty acid amides of methyl taurine; alkane monosulfonates, for example those resulting from the reaction of α-olefins (Cg^C20L with sodium bisulphate and those arising from turnover

f

of paraffins with SO 2 and Cl 2 and then hydrolysis with a base to produce a randomized sulfonate; olefin sulphonates, this term being used to describe the material produced by reacting olefins, especially C10-C20-α-olefins, with SO2 and then neutralizing and hydrolysing the reaction product. The preferred anionic washing compounds are sodium (C^-C^^) alkylbenzene sulphonates and sodium (C-^-C^g) alkyl sulphates.

Examples of suitable non-ionic washing compounds which can be used include in particular the reaction products of alkylene oxides, usually ethylene oxide, with alkyl(C8-C22)phenols, usually 5-25 EO, i.e. 5-25 units of ethylene oxide per molecule; the condensation products of aliphatic (Cg-C^g)-primary or sec.-linear or branched alcohols with ethylene oxide, usually 6-30 EO, and products produced by condensation of ethylene oxide with the reaction products of propylene oxide and ethylenediamine. Other so-called nonionic detergents include long-chain tertiary amine oxides, long-chain tertiary phosphine oxides and dialkyl sulfoxides.

Mixtures of detergent-active compounds, for example mixed anionic or mixed anionic and non-ionic compounds, can be used in the detergent mixtures, especially in the latter case to provide regulated low-foaming properties. This is to the advantage of mixtures intended for use in suds-intolerant automatic washing machines. Anionic and non-ionic washing compounds are advantageously used together in a ratio of from 3:1 to 1.5:1.

Certain amounts of amphoteric or zwitterionic detergent-active compounds can also be used in the mixtures according to the invention, but this is not normally desired because they are relatively expensive. If any amphoteric or zwitterionic detergent compounds are used, it is usually in small amounts in mixtures which are based on the very commonly used synthetic anionic and/or non-ionic detergent compounds.

According to a preferred embodiment of the invention, the detergent mixture also contains a bleaching system. The bleaching system preferably comprises a peroxy bleaching compound which is an inorganic persalt, which is preferably used in connection with an activator for this. The persalt can, for example, be sodium perborate (either monohydrate or tetrahydrate or sodium percarbonate. The activator makes the bleaching more effective at lower temperatures, i.e. in the range from ambient temperature to about 60°C, so that such bleaching systems are usually known as low-temperature bleaching systems and are well known in the art. The inorganic persalt serves to release active oxygen in solution, and the activator is usually an organic compound having one or more reactive acyl residues, which cause the formation of peracids, the latter providing a more effective bleaching effect by lower temperatures than can be achieved using the peroxy bleach compound alone.The weight ratio of the peroxy bleach compound<p>g the activator is generally from about 20:1 to about 1:1, preferably about 15:1 to about 2 :1.

The detergent mixtures according to the invention preferably contain from approx. 5 to approx. 30 by weight of the peroxy bleaching agent and approx. 0.1 to approx. 15% by weight of the activator. The total amount of the bleaching system ingredients is preferably in the range from 5 to 35% by weight, especially from approx. 6 to approx. 30% by weight.

Typical examples of suitable peroxy bleaching compounds are alkali metal perborates, both tetrahydrates and monohydrates, alkali metal percarbonates, persilicates and perphosphates, of which sodium perborate is preferred.

Activators for peroxy bleach compounds are widely described in the literature, including in British Patents 836,988, 855,735, 907,356, 907,358, 970,950, 1,003,310 and 1,246,339, US Patents 3,332,882 and 4,128,494, Canadian Patent 844 481 and South African patent specification 68/6 344. Specific suitable activators include. (a) . N-diacylated and N,N'-polyacylated amines, e.g. N,N,N',N'-tetraacetylmethylenediamine and N,N,N',N'-tetraacetylethylenediamine, N,N-diacetylaniline, N,N-diacetyl-p-toluidine; 1,3-diacylated hydantoins, e.g. 1,3-diacetyl-5,5-dimethylhydantoin and 1,3-dipropionylhydantoin; α-acetoxy-(N,N,N')-polyacylmalonamide, e.g. α-acetoxy-(N,N* ).-diacetylmalonamide; (b) . N-alkyl-N-sulfonylcarbonamides, for example, the compounds N-methyl-N-mesyl-acetamide, N-methyl-N-mesyl-benzamide, N-methyl-N-mesyl-p-nitrobenzamide and N-methyl-N -mesyl-p-methoxybenzamide; (c) N-acylated cyclic hydrazides, acylated triazones or urazoles, e.g. monoacetylmaleic acid hydrazide; (d) .. 0,N,NT-trisubstituted hydroxylamines, e.g. O^-benzoyl-N,N-succinylhydroxylamine, O-acetyl-N,N-succinylhydroxylamine, O-p-methoxybenzoyl-N,N-succinylhydroxylamine, 0-p-nitrobenzoylT-N,N-succinylhydroxylamine and 0,N,N -triacetyl-hydroxylamine; (e) N,N'-diacylsulfuryl amides, e.g. N,N'-dimethyl-N,.N'-diacetyl-sulfurylamide and N,N'-diethyl-N,N<1->dipropionylsulfurylamide; (f). Triacylcyanurates, e.g. triacetyl cyanurate and tribenzoyl cyanurate; (g) . Carboxylic anhydrides, e.g. benzoic anhydride, m-chloro-benzoic anhydride, phthalic anhydride and 4-chlorophthalic anhydride. (h) Sugar residues, e.g. glycosepentaacetate; (i) 1,3-diacyl-4,5-diacyloxy-imidazolidine, e.g. 1,3-diformyl-4,5-diacetoxy-imidazolidine, 1,3-diacetyl-4,5-diacetoxy-imidazoline, 1,3-diacetyl-4,5-dipropionyloxy-imidazoline; (j) Tetraacetyl glycoluril and tetrapropionyl glycoluril; (k) Diacylated 2,5-diketopiperazines, e.g. 1,4-diacetyl-2,5-diketopiperazine, 1,4-dipropionyl-2,5-diketopiperazine and 1,4-dipropionyl-3,6-dimethyl-2,5-diketopiperazine; (1) Acylation products of prbpropylenediurea or 2,2-dimethyl-propylenediurea (2,4,6,8-tetraazabicyclo-(3,3,1)-nona-3,7-dione or its 9,9-dimethyl derivative), especially tetraacetyl- or tetrapropionyl-propylenediurea or their dimethyl derivatives;

(ral) Carbonic acid esters, eg the sodium salts of p-(ethoxy-carbonyloxy)-benzoic acid and p-(propoxy-carbonyloxy)-benzenesulfonic acid;

(n) α-acyloxy-(N,N')-polyacylmalonamides, e.g. α-acetoxy-(N,N')-diacetylmaloriamide.

The N-diacylated and N, N 1 ^-poly acyler te amines mentioned below

(a) is of particular interest, especially N,N,N',N'-tetraacetyl-ethylenediamine (TAED).

It is preferred to use the activator in granular form, preferably where the activator is finely divided as described in our British Patent Application No. 80 21979. Specifically, it is preferred to have an activator with an average particle size of less than 150 ym, which provides significant improvement in bleaching. efficiency. The sedimentation losses, when using an activator with an average particle size of less than 150 µm, are significantly reduced. Even better bleaching performance is achieved if the average particle size of the activator is less than 100 µm. However, too small a particle size gives increased decomposition, dust formation and handling problems, and although particle sizes below 100 ym can give improved bleaching efficiency, it is desirable that the activator has no more than 20% by weight of particles with a size of less than 50 ym. On the other hand, the activator may have a certain amount of particles with a size above 150 ym, but it should not contain more than 5% by weight of particles > 300 ym, and not more than 20% by weight of particles > 200 ym, preferably > 150 ym. It should be understood that these particle sizes refer to the activator present in the granules, and not to the granules themselves. The latter has one particle size where the main part varies from 100 to 2000 ym, preferably 250-1000 ym. Up to 5% by weight of granules with a particle size > 1700 ym and up to 10% by weight of granules < 250 ym is tolerable. The granules incorporating the activator, preferably in this finely divided form, can be obtained by granulating the activator with a suitable carrier material, for example sodium tripolyphosphate and/or potassium tripolyphosphate. Other granulation methods, for example the use of organic and/or inorganic granulation aids, can also be used usefully. The granules can then be dried, if necessary. Basically, any granulation process is applicable, when only the granule contains the activator and when only the other materials present in the granule do not adversely affect

.the activator.

It is particularly preferred to include in the detergent mixtures a stabilizer for the bleaching system, for example ethylenediaminetetramethylenephosphonate and diethylenediaminetriaminepentamethylenephosphonate. These stabilizers can be used in acid or salt form, especially in the form of calcium, magnesium, zinc or aluminum salt form, as described in our British patent application No. 2 048 930.

Apart from the components already mentioned, the detergent mixtures according to the invention may contain any of the conventional additives in the quantities in which such materials are normally used in laundry detergent mixtures. Examples of these additives include foam enhancers, for example alkanolamides/especially the monoethanolamides derived from palm kernel fatty acids and coconut fatty acids; foaming, reducing agents, for example alkyl phosphates, silicones,

or alkylphosphonic acids which are incorporated in petroleum jelly, wax or mineral oil; soil carriers, for example sodium carboxymethyl cellulose and cellulose ethers; fabric softeners; inorganic salts, such as sodium sulfate and sodium carbonate; and, usually present in very small amounts, fluorescent agents, perfume, enzymes, such as proteases and amylases.

It may be desirable to include in the product a quantity of . an alkali metal silicate,. in particular sodium ortho-, -meta- or preferably neutral or alkaline silicate. The presence of such alkali metal silicates at levels which are at least approx.

1%, and preferably from approx. 5 to approx. 15% by weight of the mixture, is advantageous with regard to reducing corrosion of metal parts in washing machines, in addition to providing processing advantages and generally improved powder properties. The stronger alkaline ortho- and metasilicates would normally only be used

in lower amounts within this range, in admixture with the neutral or alkaline silicates.

The product according to the invention is preferably alkaline, but not too strongly alkaline, as this could result in fabric damage and also be dangerous for use in the household. In practice, the product should ideally give a pH value of from approx. 8.5 to approx. 11 in use in a watery wash bath. It is particularly preferred for household products that they have a pH value of from approx. 9.0 to approx. 10.5, as lower pH values tend to be less effective for optimum detergency, and stronger alkaline products can be dangerous if misused. The pH value is measured at the lowest normal use concentration of 0.1 wt/vol.%

of the product in water of 12°H (Ca) (French permanent hardness,

only calcium), at 50°C so that a satisfactory degree of alkalinity can be ensured in use at all normal product concentrations. If necessary, up to 10% by weight of alkali metal carbonate, preferably sodium carbonate, can be included in order to raise the pH value and maintain adequate buffering capacity in the presence of acidic dirt.

If carbonate or phosphates are present, it may be desirable to include in the product according to the invention one or more anti-deposition agents, in order to reduce any tendency to form inorganic deposits on washed laundry. The amount of any such anti-deposition agent is normally from approx. 0.1 to approx. 5% by weight, preferably from approx. 0.2 to approx. 1.5% by weight, calculated on the mixture. The preferred antifouling agents are anionic polyelectrolytes, especially polymeric aliphatic carboxylates, or organic phosphonates.

The detergent mixtures according to the invention should preferably be in free-flowing particle form, for example as powder or granules, and can be produced by any of the techniques that are usually used in the production of such detergent preparations, for example by slurry and spray drying processes. It is preferred that the method used to make the mixtures should result in a product that has a moisture content of no more than approx. 12%, preferably from approx. 4 to approx. 10%, by weight.

The detergent mixtures according to the invention can also be in the form of bars or tablets, or in liquid form.

In the following, the invention will be illustrated by means of the non-limiting examples.

EXAMPLES

In the examples that follow, the washing capabilities of laundry baths containing different builder systems were compared by measuring the reflectivity of a clay-stained polyester/cotton fabric sample before and after washing in the Tergotometer. The reflectivity was measured with a Carl Zeiss Elrepho Reflecto meter, and the increase in reflectivity upon washing (AR) was calculated as a measure of washability.

In each case, a wash bath was made using the ingredients listed below, in the concentrations indicated, in water of 40°FH (Ca). The washing bath was allowed to equilibrate for 15 minutes. Fabric test pieces (four pieces per liter, each measuring 76.2 mm x 76.2 mm) were then added, and a 20 minute wash at 80°C, pH'10.0 and 55 rpm. agitation was carried out, followed by rinsing in water of the same hardness as the water used to make the wash bath.

The ingredients and concentrations were as follows:

x The soap was included for foam control purposes and was present in addition to the soap included in the washing additive according to the invention. It will be seen that the washing additive according to the invention was used in concentrations of from 2.00 to 5.00 g/litre, and the other components in the mixtures were used in a constant total concentration of 2.495 g/litre, so that the total concentration ranged from 4.495 to 7.495 g/litre. The percentage of the total mixture that the washing additive according to the invention constituted was therefore at each concentration of the latter as follows:

All percentages that. are given in the examples are by weight and are based on the anhydrous materials.

EXAMPLE 1

The detergency of mixtures containing a ternary builder system (washing additive) according to the invention was compared, in water of 40°FH at a range of concentrations, with the values of control mixtures containing simple or binary builder systems. The aluminosilicate used was Zeolite A, the soap was hardened tallow soap, and NTA was in the form of its trisodium salt. The results were as follows:

EXAMPLE 2

The procedure from Example 1 was repeated using other proportions of zeolite, soap and NTA. The results were as follows:

Claims (10)

1. Washing additive, characterized in that it essentially consists of: (al from 25 to 97% by weight of a crystalline or amorphous aluminosilicate cation exchange material, (b) from 3 to 75 wt.i, in total, of (i) one or more water-soluble soaps of ci q~ C22 -^ett~ acids, at least 60% by weight of the total soap being saturated material, (ii). nitrile triacetic acid or a water-soluble salt thereof, the weight ratio between (i) and (ii) being from 1:10 to 10:1, and (i) being present in an amount of at least 12% by weight, based on the total weight of ( a) and (b) . 2. Washing additive as specified in claim 1, characterized in that the soap (i) is present in an amount of at least 15% by weight, based on the combined weight of (a) and (b). 3. Washing additive as specified in claim 1 or 2, characterized in that at least 80% by weight of the soap (i) is saturated material. - 4. Washing additive as specified in claim 3, characterized in that the soap (i) generally consists substantially entirely of saturated material. 5. Washing additive as stated in any one of claims 1 to 4, characterized in that the soap (i) contains at least 5% by weight of material having a chain length of C^ g and higher and at least 1% of material having a chain length of C, . and lower. 6. Washing additive as specified in claim 5, characterized by ..that the soap (i) contains at least 60 wt.l of material having a chain length of C^ g and higher and at least 1% of material having a chain length of and lower. 7. Washing additive as stated in claim 5, characterized in that the soap (i) contains at least 60% by weight of material having a chain length of C,. and lower and at least 5% of material which. have a chain length of C^ g and higher. 8. Washing additive as stated in any one of claims 1 to 7, characterized in that it contains from 10 to 60% by weight, by weight, of (i) and (ii). 9. Washing additive as stated in any one of claims 1 to 8, characterized in that the weight ratio between (i) to (ii) is from 3:1 to 1:1. 10. Detergent mixture, characterized in that it comprises from 3 to 90% by weight of at least one synthetic detergent active material and from 10 to 97% by weight of a washing additive as stated in any of claims 1 to 9.