GB2292746A - Bleach compositions - Google Patents

Abstract

A method is disclosed of enhancing the performance of conventional sodium perborate-based domestic detergent powders, particularly at cool water temperatures of about 30 DEG C, using reagents which introduce no more than 5 parts per million of transition metal ion into the washwater in the machine and into the drainings from the machine. In a preferred embodiment of the invention the reagents are related to conventional synthetic zeolites or pseudo-zeolites (namely, boronated felspathoids) which have been pre-treated with small amounts (usually about 1% by weight) of metal salts such as ferrous sulphate, or preferably, copper sulphate.

Description

This invention relates mainly but not solely to the manufacture and formulation of detergents containing peroxygen compounds intended for use in domestic automatic washing machines. These fabric washing compositions can be used for washing at high temperatures as well as low temperatures but are principally intended for use at temperatures significantly less than 40"C.

Inorganic persalts such as sodium perborate and sodium percarbonate are widely used as bleaching agents in detergent compositions especially in the UK and Europe. These persalts provide a very satisfactory bleaching action when the detergent composition is used at high temperatures, which may occasionally exceed 800C, but their action becomes progressively less effective the lower the temperature at which the washing system is operated.

This rather critical temperature dependency of the persalt bleach system represents a drawback of continually increasing importance since it may be expected that the common acceptance of the high temperatures demanded for full efficiency will decrease in response to the need to save energy and time. Consequently, where a fully effective bleach at cool temperatures is essential resort has been made to chlorine-containing bleaches of various types, despite their disadvantages: the diminution in fabric strength, the discolouration of the dyes, and, hence, the reduction in useful life of the article itself.

In the course of the efforts to extend the range of application and to continue to benefit from the inherent technical advantages of the persalt bleach system it has been shown that certain substances, frequently called "activators", have the power to amplify the bleaching action of the persalts at temperatures below about 500C at which temperature threshold many domestic washing machines are operated. Although these activators can be shown to be extremely effective in quantitative in vitro experiments a completely convincing material has not thus far emerged.Sometimes the activator must be used in high proportion in order to achieve satisfactory results; or it may be particularly costly; or it may not be environmentally benign; or it must be used only in conjunction with specific peroxygen bleaching agents; or it provokes instability and hence a low shelf life in the detergent powder product; or it requires a non-routine or inconvenient process of incorporation into the detergent product. A review of the activators described heretofore has been given, for example, by Finley and Blumbergs in European Patent Application 79302525.8.It includes references to carboxylic acid anhydrides, carboxylic esters, [N-substituted] N-acyl nitro-benzenesulphoamides, N-benzoylsaccharin, aromatic sulphonates and sulphonyl chlorides, N-sulphonylimides, phosphoric-carboxylic anhydrides, phosphonic-carboxylic anhydrides, N-acylazoles, phenyl sulphonates, and heterocyclic sulphonate esters. An alternative procedure has been described by Clements and Leigh in USP 4,338,210 by which the persalt is converted in situ to a peracid by hydrolysis or perhydrolysis and then treated, again in situ, with an organic or inorganic material which delivers bromide ions into the aqueous medium.

It is well known that dilute sodium perborate solutions will decompose spontaneously at room temperatures - but the reaction takes a long time to go to completion, a time much longer than is normally available in the usual domestic washing machine programmes. On the other hand, it is also known that the reaction proceeds very rapidly if certain metal ions are introduced: the most effective are those of metals of variable valency, as for instance, iron, copper, cobalt, manganese, and nickel. Konecy and Meeker, in USP 3,156,654 11964] describe processes for improving the bleaching action of peroxy compounds using heavy metals which are supported and restrained by special chelating agents. They give as an example the complex formed from cobalt sulphate and pyridine 2-carboxylic acid.

In more recent work, Namnath, in EPA 85302410.7, has claimed that an effective catalyst for the decomposition of peroxy compounds via the true bleaching mode can be prepared by adsorbing a water-soluble manganese (II) salt onto a solid inorganic silica support material. In a letter to "Nature" (369, 637-639, (1994)) Hage and his colleagues describe a sophistication of ideas such as Namnath's based upon the discovery that complexes of manganese with derivatives of the nitrogen heterocycle triazcylononane (and its dimer) are effective oxidation catalysts. The scientific aspects are presented by Comyns, in a commentary on Hage's development ("Nature", 369, 609 - 610, 1994).The active species in the bleaching reagent, he says, is the uncharged hydroxyl radical OH as for instance in: Fe2 + H202 ---- > Fe3+ + OH + OH .................. (1) In the case of the subject of the present invention, which depends on the use of a copper reagent, a reductant is necessary to provoke the reaction: Cu' + H202 ---- > Cu2 + OH + OH .................. (2) against the influence of the competing reaction arising from the presence of catalase naturally occurring in the body-soils and perspiration: 2H2O2 catalase > 2H2O + O2 ....................... (3) a reaction which generates no bleach-active species.

It is known by those concerned with textile dyeing and finishing that body soils and perspiration re-ionises the protective copper applied to "aftercoppered" cotton goods processed with direct dyes so rendering the colour vulnerable to perspiration and rubbing. Synthetic perspiration compounds used in standard test procedures [BS 1006: 1978 "Colour Fastness to Perspiration"; AATCC 15-1985] are commercially available from the Shirley Institute and have been used in tests with our product: there are two forms, one acid, one alkaline, both based on histadine mono-hydrochloride monohydrate.

In the absence of serious interference from catalase (Reaction (3)) our process could proceed through the peroxy anion: H202 ===== 2H + o22- . . . . . . . . . . . . . . (4) O22- + Cu2+ --- > Cu+ + O2- . . . . . . . . . . . . . . (5) O2- + Cu2+ --- > Cu+ + O2 . . . . . . . . . . . . . . (6) then H202 + Cu' ---- > Cu2 + OH + OH . . . . . . . . . . (7) Our experimental evidence is that Reaction (7) proceeds preferentially in our process, the opposing Reaction (3) being hindered or halted by the reaction with the copper, whilst Reaction (6) is not likely to be ratedetermining.

It is the purpose of this present invention to provide a means of so improving the efficiency of a persalt-based heavy duty domestic detergent powder that it will respond sufficiently well to the lower temperatures which will be increasingly preferred by the users that no difference will be apparent in the appearance of the domestic articles so washed from that appearance which a normally critical person would expect of the same powder used at its more usual temperatures. By "more usual temperatures" we mean between 600C and 800C, and by "lower temperatures" we mean 300C to 400C.

It is also an object of this invention to achieve this desired effect without: (i) .. significantly increasing the cost of the raw materials used to make the detergent composition; (ii) .. requiring the adoption of inconvenient or unconventional production processes; (iii) .. introducing biologically undesirable or chemically active species into the effluent; (iv) .. undermining the effectiveness of the other ingredients in the detergent composition; (v) .. disadvantageously increasing the time the soiled goods are retained in the washing machine; (vi) .. impairing the properties, in terms of tensile strength and resistance to abrasion, of the washed fabric; (vii) .. impairing the fastness of the dyes applied to the fabric when compared to the known fastness properties of those dyes to washing at the temperatures specified.

The present invention provides a method of making such a detergent composition which has improved properties when used at temperatures between 300C and 400C by incorporating a "modified boronated felspathoid", as hereinafter defined, with a conventional perborate-based detergent, the improved composition containing between 10% and 20% [by weight] of the modified boronated felspathoid.

THE REAGENTS A "boronated felspathoid" may be described as a synthetic alkali metal alumino silicate having a crystal structure similar to that of the mineral "nosean" but containing a boron compound entrapped within that structure.

Such compounds have previously been disclosed by Barrer and Freund (J.Chem.Soc.[Dalton], 1974, pp 1049 - 1053) though the compounds are therein described as "boron-containing zeolites".

The boronated felspathoid powder product used according to the present invention can be made by any of the conventional processes for hydrothermal crystallisation of zeolites [for example, of sodalite hydrate], from a source of silica, a source of alumina, and a source of alkali metal preferably sodium on the grounds of initial cost, the simplicity of the reaction, and the extent of the conversion to the true "nosean"-type product, but with a source of boron such as boric acid or sodium borate in the synthesis mixture. The source of silica and the source of alumina can be any kaolinite material in which the proportions of Awl203 to SiO, are in the molecular ratio of 1:2. Since any other materials will remain largely unreacted in the process to be described it is advisable for the raw materials chosen to be not less than 98% pure.

Two examples of the production of such a boronated felspathoid are described in E.P.C. Application No. 81300325.8 as follows: Example 1.

1712g sodium hydroxide and 751g borax decahydrate were dissolved in 4000g distilled water in a stainless steel beaker. 1085g china clay having a nominal particle size below 1 micron were added and the mixture stirred for 24 hours at 850C. (From observation it appeared that the process of hydrothermal crystallisation seemed to be complete after about 6 hours). After filtering, washing and drying overnight at 1300C, 1175g of product were obtained. Its X-ray diffraction powder pattern was substantially identical to that of mineral nosean suggesting the skeletal structure of the cage around the boron moiety.

Chemical analysis showed that the product contained 20.6% Na2O, 5.0% B203, 31.4% A1203, 39.8% SiO2, 0.8% Fe2O3, the balance being water.

The particle size was mostly less than 5-10 microns [estimated microscopically]. lOg of this product was stirred with 100g distilled water for 6 hours at 250C but no more than one fiftieth of B2O3 was leached out.

A determination of the physical characteristics of this product using the "Sedigraph" instrument and taking a specific gravity figure of 2.38 produced these results: Nominal particle diameter Percentage finer than 35 microns ..................... 100% 20 " ..................... 97% 10 " ..................... 85% 6 " ..................... 65% 5 " ..................... 52% 4 " ..................... 35% 1 " ..................... 3% Samples of the product prepared according to the method described in Example 1 have been presented for assessments of acute toxicity as follows: (i) the modified Draize Eye Irritation Test in the Rabbit, (ii) Draize Skin Irritation Test in the Rabbit, (iii) Gross Acute Oral Toxicity Assay in the Rat.

The indicative results were that the product is, respectively: (i) not a severe ocular irritant, (ii) classified only as a mild primary irritant, (iii) exceeding the level of 500 mg/kg of body weight for the minimum acute oral lethal dose.

Example 2 A boronated felspathoid having the same properties as that produced by Example 1 was made using sodium aluminate (113g) and "M 75" sodium silicate (225g) as the source of alumina and silica [instead of china clay] with 154g sodium hydroxide, 96g borax and 1105g water. The sodium aluminate was dissolved in half the total water, the other materials in the remaining water. The solutions were combined at 400C and then stirred at 800C for one day. The product was filtered off, well washed until the pH of the washing water was not more than 10, and then the product was oven dried at 1000C.

Studies of the effect of the choice of china clay, as in the method of Example 1, showed that there was very little difference in the apparent chemical composition of the product; however there were some minor variations which could be induced in the particle size distribution of the product. As a consequence of the intrinsic fineness of the material produced (about 85% is less than 10 microns) it will not normally be necessary to refine it further, as for instance by grinding or classifying, to render it suitable for the purposes of the invention. The products of these processes are described generically in this text as 'Nosean "B"'.

It is of interest to note that the product made by the methods described above did not exhibit any significant ion-exchange capacity, that is to say, neither calcium nor magnesium ions could be removed from an aqueous solution to any useful extent. As is well known other types of zeolites are suggested for use in detergent compositions for this particular purpose, eg, Corkill, Madison & Burns in B.P. 1,429143 (24th March 1976).

The "modification" of this boronated felspathoid proposed is intended to develop the known ability of a suitable metal compound to decompose sodium perborate but, by combining it with the boronated felspathoid, to do so at a slow, steady rate whilst taking the reaction to completion within the shorter time scales usually provided in domestic automatic washing machines loaded with soiled domestic articles, and without introducing into the effluent undesirably large amounts of contaminating heavy metal salts.

Copper sulphate has been found to be one such suitable reagent, the complete reagent being made in the following manner: Example 3 Solutions of copper sulphate crystals were prepared at concentrations of 50g/litre and 5g/litre. 200g of the dried products derived from the procedures described above [Examples 1 & 2] were stirred in a domestic high speed, high shear mixer; the copper solutions were added dropwise to produce loadings of between 0.1% and 1% copper sulphate (as crystals) on the powder.

THE TEST TECHNIQUES The first scheme of evaluation preferred for defining the invention is the most direct one possible; a household front loading washing machine with a chamber capacity of 20 litres was used, and 5 kilos of "normally"-soiled garments weighed for each cycle; the charge of detergent (with and without the added modified boronated felspathoid) was set at half the weight of the manufacturer's recommendation for the "hot" wash [taking approximately 30 minutes at that "hot" temperature], and the cycle time set at half the hot wash recommendation [approximately 15 minutes]. Temperature measurements were taken at the discharge point.In effect, this meant that cotton goods would be washed at the "cool" temperature setting recommended as appropriate for "delicate fabrics; it also means that under these circumstances the majority of the soiled cotton goods will be found to be imperfectly washed and unacceptable. Changes in procedure of this severity are necessary because of the very high efficiency of modern detergent powders.

In many of the "activator" experiments described in the literature "teastained" or "coffee-stained" fabrics are used and the change in bleaching power measured by the change in reflectance. This has the advantage of producing objective quantifiable results but the disadvantage that "teastains" or "coffee-stains" can not easily be standardised since they are susceptible to variation in reaction according to source, age of stain, water quality, liquor/goods ratio in the wash cycle, the temperature tolerance, and adventitious metal ion. But more important, in actual domestic practice, conventional detergent powders will not remove any tea or coffee stains to an extent acceptable to the user, and either a biological powder treatment or an old-fashioned "rolling boil" process is necessary.

Hence "improvements" in detergent power, as determined by the change in reflectance of a tea or coffee stain, though they are helpful in advancing an investigation in the laboratory, may only have a marginal practical relevance. Where instrumental measurements became necessary in this enquiry a coffee-stained cotton poplin aged four days was used. The sophisticated technique used has been described by H. R. Cooper in the "Shirley Institute Bulletin", Volume 57, Number 1, 1984, his results are given in terms both of a visual rating arrived at by skilled assessors and an instrumental rating.

For this present test series three other procedures were used to assist in interpreting the instrumental data: (i) colour differences from soiled unwashed sample, (ii) reflectance values at 460mm, (iii) percentage of recovery towards complete stain removal based upon reflectance differences from those of the unwashed sample.

H. R. Cooper further remarks that commercial detergent compositions differ in their responses to the presence of the primary staining species: fatty, proteinaceous, and "oxidisable"; in a later contribution the significance of a fourth category, of particulate soils, has been emphasised. The application of the techniques of colour measurement, he writes, enables confident assessments to be made of different detergents: but the results are relative, not absolute, and depend upon the washing machine, the washing conditions, the fabric construction, and the stains selected. In the present case, where bleaching action is of a principal interest, the important stains are "oxidisable" and the domestically acceptable results include "freshness" as well as freedom from stain.Our finding in these experiments is that the system is effective IN THE PRESENCE OF "NATURAL" PERSPIRATION STAINS AND SOILS. Experiments at Newcastle upon Tyne Polytechnic have shown that high concentrations of perspiration material are necessary - our own further work has shown that these necessary high concentrations are sufficiently developed at the localised [stained] sites which it is the object of the washing process to clear.

However, the method of assessment used continually throughout this enquiry was direct and subjective: "was the general quality of the wash acceptable or not?" The "Weber-Fechner Rule" is to the effect that "in subjective assessments of intensity the least increase of stimulus that is just discernible bears a constant ratio to the original stimulus: by integration this leads to a linear relation between the logarithm of the stimulus and the measure of the sensation". The quotation is from Tabor who was writing in 1954 on Mohs' Hardness Scale in Proc. Roy. Soc., 65, 3B p249 (1954).Mohs had himself worked out in 1824 a purely subjective relationship between one mineral and others in terms of his impression of their hardness; by 1954 Tabor had shown that Mohs's subjective assessment has a rational basis; by 1981 Torrance writing in "Wear", 68, p263 (1981) had confirmed the validity of Tabor's work in theoretical and quantitative terms. There are other similar examples, and one may conclude in general that if a subjective assessment is carried out in a sufficiently conscientious and "craftsman-like" manner and if it has a direct relevance to the matter at issue then the quantitative confirmation can be awaited with some confidence.

For these reasons it was decided that the routine method of assessment would be that normally adopted by a critical housewife: the finished goods were required to be washed and clean to the same standards as would be expected of that detergent powder at the full recommended dose, time and temperature appropriate to soiled cotton; constant references back to the "full charge" system were made during the course of the enquiry to determine that the critical standards were maintained. It is common in industrial practice too use standard fabrics printed with standard stains [the "EMPA" cloths] and then assess the extent that a given wash system removes those stains instrumentally using a reflectometer.The perturbing factor with this procedure is that the human senses of smell, sight, and touch are very much more sensitive than are any practical physical instruments but become "saturated" much sooner whilst the instruments continue to register responses that the human senses would discard.

The charge weight recommended by most manufacturers of the conventional spray dried powder products is 100g; in the first trials the weight taken was 50g (save for reference tests for which 100g was taken) and in addition quantities of the boronated felspathoid, modified or not, of 10g and, in another series of tests, 20g were introduced into the chamber of the washing machine at the same time as the 50g of detergent powder. In another series a "detergent concentrate" was used at 35g, for reference, but at 15g for test, with 10g and then 20g of the boronated felspathoid, modified or not.

The commercial detergents tested vary quite widely in composition but, in general, fit the pattern illustrated in the table (Nos 1-4 are "conventional", No 5 is a "concentrate").

Detergent Composition 1 2 3 4 5 Sodium alkyl benzene sulphonate 6% 6% 6% 6% 20% Fatty alcohol ethoxylate 4 4 4 4 20 Sodium carboxy methyl cellulose 4 4 4 4 18 Sodium tripolyphosphate 34 34 34 34 28 Sodium perborate 25 25 - 25 9 Sodium percarbonate - - 20 - Sodium silicate 6 6 6 6 4 Sodium sulphate 20 20 25 18 Enzyme concentrate - - - 2 Optical whitener 1 1 1 1 1 Note that in the table above, the water content, either introduced as hydrated material or as moisture pick-up, is ignored. Proportions are given in percentages.

The standard detergent composition used in the washing machine tests in which the various copper sulphate loadings were examined systematically was ....... commercial concentrate ...... 20g, i.e., lg/litre ....... sodium perborate ...... 20g, i.e., lg/litre ....... (modified) boronated felspathoid ...... 20g, i.e., lg/litre Assuming the commercial concentrate has a composition similar to that shown in the table (No 5) the percentage contributions of the functional ingredients, and the final concentrations of active ingredients in the wash water, will be:: ...... synthetic detergents ..... 14 ..... 0.14g/litre ...... antiredeposition agents ...... organic ..... 7 ..... 0.07g/litre ...... sodium tripolyphosphate ..... 10 ..... 0.10g/litre ...... sodium sulphate (or silicate) ..... 3 ..... 0.03g/litre ...... sodium perborate ..... 36 ..... 0.36g/litre ...... modified boronated felspathoid ..... 30 ..... 0.30g/litre ..........................................Total 100 Inspection of the fabric articles treated in the manner described show that, relative to the sodium perborate content, the addition of between 20% and 180%, preferably 70% to 130%, of the modified boronated felspathoid containing about 1.0% of the copper salt will be effective in producing, in a typical domestic wash, whiteness, freshness, and cleanliness of acceptable standards at wash temperatures not exceeding 400C, preferably around 300C.

Exploration of this phenomenon over the full range of copper sulphate loadings undertaken showed that the activity was perceptible at 0.1% in vitro but would not produce washed results in the machine acceptable to a critical housewife. In the washing machine conditions just described a loading of 1% copper sulphate represents a nominal concentration of metal ion of 2.6 ppm. In the powder product the metal ion appears to be immobilised on the insoluble boronated felspathoid). Higher loadings of copper sulphate up to 20% have also been examined but do not appear to offer any advantage in domestic conditions though the reaction still appears to be steady and may be appropriate in industrial conditions where proper attention to the effluent may be made.In our in vitro experiments, the higher the loading of copper ion on the boronated felspathoid, the faster the decomposition of a given charge of perborate goes to completion.

Some of the tests carried out, with their instrumental results and subjective impressions, follow.

Detergent composition: A .... Powder concentrate .......................... 1 g/litre ... A B .... Sodium perborate tetrahydrate .............. 1 g/litre ... B C .... Nosean 'B' ................................. 1 g/litre ... C D .... Nosean 'B' modified with ferrous iron ...... 1 g/litre ... D E .... Nosean 'B' modified with cupric copper ...... 1 g/litre ... E Process conditions Stain: solubilised coffee at 101 g/litre, padded, dried, aged 4 days.

Sample Temperature C Reagents Wash quality 1 75+ AB acceptable 2 35 AB unacceptable 3 35 ABD acceptable 4 35 ABC acceptable 5 75+ ABC acceptable 6 35 ABE acceptable 0 - - not washed Instrumental Assessments Sample Colour difference Reflectance Percent recovery from stained fabric at 460 nm of reflectance unwashed 1 14.0 71.1 45.2 2 5.2 51.4 11.3 3 5.8 51.2 11.2 4 6.1 52.9 14.6 5 17.3 79.8 54.9 6 6.6 63.7 15.9 Staining Scale Ratings Sample Visual rating Instrumental rating 0 2 2.0 1 2/3 2.8 2 2/3 2.2 3 2/3 2.2 4 2/3 2.3 5 3/4 3.1 6 2/3 2.5 There are subsidiary properties of the modified and unmodified boronated felspathoid of interest. For instance, they impart an antistatic effect to synthetic fibre fabrics.This is to say that the common methods preferred domestically to ensure such garments will be wearable, that is, usually, the application of a long-chain quaternary compound, is no longer necessary.

This effect is durable only to the extent that it will withstand two further wash cycles, but of course it can be continuously regenerated if the detergent incorporates the boronated felspathoid product.

We have also observed, using test samples of woven terry towelling, that goods washed, as described, in the presence of the boronated felspathoid, modified or not, acquire a fullness of handle and an improvement in foldedbulk effects which persist for several days after the wash. It is further the case that certain wool weight acrylic fabrics which are at a stage of wear which, after washing, generally suggests to the critical housewife that she would normally expect to iron such garments will no longer need such ironing.

No complete explanation for the mechanisms which underlie these phenomena has yet emerged. However, there are known properties of the materials involved which may contribute, for instance: (i) for an inorganic compound the boronated felspathoid has an extremely high perceived oil absorption (37ml linseed oll/lOOg felspathoid) only exceeded by certain calcined high surface area materials; this may suggest that a contribution to whiteness and hence to apparent bleaching power may be an initial adsorption or (less likely) absorption of greasy matter; (ii) the boronated felspathoid slowly yields up a proportion of its sodium content, which implies a "micro-climate" of hydroxyl ions in its very close proximity, and subsequently, in the proximity of the fibre surface as well; this may suggest the possibility of some more active support of the normal detergent process; (iii) in this context it is relevant to refer to the known fading of "after-coppered" direct cotton dyes which is induced by perspiration staining - the perspiration re-ionises the copper depriving the dyestuff of its support; (iv) the effects secondary to the promotion of the perborate bleaching action, that is the improvement in handle, the antistatic effects on synthetic fabrics, and the crease shedding effect on acrylics may be explained by the development of a [relatively] swollen and hydrophilic layer around the fabric surface induced by the very high, very localised, alkalinity. We have considered this effect to be a form of "keto-enol" transformation.

In further experimental work the properties of boronated felspathoids modified by other variable valency heavy metal salts, principally cobalt and manganese, have been examined. A particularly interesting example which gave excellent wash results in practice was prepared from ferrous sulphate stablised in the ferrous state by ascorbic acid [Vitamin C]. The compositions examined contained 0.5% ascorbic acid [by weight] and between 0.1% and 0.5% Fe, ie, approximately 0.5% to 2.5% ferrous sulphate heptahydrate [by weight].

Example 4 2g of ferrous sulphate crystals and lg of technical quality ascorbic acid were dissolved in 20 ml water to form a clear, stable, slightly yellow solution. The mixed solution was added dropwise to 200g of boronated felspathoid in a high speed, high shear mixer.

This is an example of "redox poising" in that the composition in service must maintain a higher proportion of the metal in its lower valency state for it to be effective as a catalyst - but to do so under strongly oxidising conditions.

In the tests described above the modified boronated felspathoid was added at the washing machine, but it is also possible to incorporate it with the other ingredients of the commercial detergent powder at the manufacturer's plant. More importantly, because the modified boronated felspathoid is resistant to high temperatures without decomposing, it is possible to incorporate it in the slurry which is to be spray dried as the routine method of manufacture; it is not necessary to incorporate it at any later, and less convenient, stage as is the case with sodium perborate and sodium percarbonate.It will further be observed that the addition of [modifiedj boronated felspathoid will usually impart "free flowing" properties to such compositions obviating any practical difficulties which may arise from their hydroscopic nature: it will be found that an addition of between 0.5% and 1% of the [modified] boronated felspathoid is necessary to provoke this effect; however, compositions which themselves contain more than about 5-7% water [as, for instance, the product from Example 4] will not be so effective.

To varying degrees the characteristics and performance of a perborate-based domestic detergent concentrate to be operated at 1litre and at 350C will be improved by the addition of the modified boronated felspathoid herein described in these respects: detergency, perborate activity.

"antistat" finish [on synthetics], "full" finish [on cottons], with product [packet] shelf life unaffected.

Two other materials with structural similarities to the modified boronated felspathoid have been examined to assess their relative contribution to these properties.

a) a felspathoid ["sodalite"] prepared in a manner similar to that described under Example 1 but without the borax.

(b) "Zeolite 4A" ~ a commercial material as produced by Crosfield Chemie BV with the approximate composition: soda .............. 17.5 - 18.5% alumina .......... 28 - 30% silica ............ 31 - 34% water ............. 18 - 22% In some cases, these materials have been modified with 0.15% copper [Cu++] in the way described for Example 3. The dried products were assessed in domestic wash test as previously described. The impressions of the results obtained are summarised in the Table.

Property Nosean B Sodalite Zeolite 4A detergency xxx xx x perborate activity xxx - x antistat xxx - x fullness xxx water softening x shelf life xxx xxx Notes: (i) The symbols mean: xxx ............. effective xx ............. noticeable x ............. not usefully developed - ............. not tested, or not observed (ii) "perborate activity" relates to "coppered" variants only.

Claims (4)

What we claim is:

1. A peroxy - compound based detergent composition in which the loadings of the active transition metal ion in the wash water or in the drainings from the washing machine shall not exceed 5 parts per million.

2. A detergent composition having improved properties at 350C - 400C consisting of a conventional perborate - containing, or percarbonate - containing detergent mixture in which have been incorporated between 10% and 35%, by weight, of a modified boronated felspathoid as hereinbefore defined.

3. A detergent composition as in Claim 2 in which the modified boronated felspathoid contains between 0.5% and 5% of a water soluble salt of a transition metal, iron, or, preferably, copper.

4. A detergent composition as in Claim 2 in which the metal salt is a salt of ferrous iron preferably ferrous sulphate which containing, in addition, between 0.5% and 5% of ascorbic acid.