NO169724B - Particulate, softening detergent mixture. - Google Patents

Description

The invention relates to a paticle-shaped, fabric-softening detergent, and more specifically such a detergent which contains certain relative amounts of synthetic, organic surfactant, builder's salt, bentonite and water-insoluble soap.

Particulate, built, synthetic, organic detergents have been produced by spray drying a slurry of surfactant, building salt and suitable auxiliary additives, and such products have been marketed with great success for a number of years. Recently, fabric softening materials have been incorporated into such detergents so that clothes washed with the detergent are softened at the same time, thereby avoiding the previously necessary additions of softeners to the rinse water. Cationic softeners, such as those that have previously been used for rinse water treatment of laundry to soften it, which have been incorporated into detergents as softeners, can cause discoloration (yellowing) of the laundry after repeated washings. They also react with anionic surfactants, and sometimes they deactivate fluorescent whitening agents that can be important ingredients in detergents. In some commercial products, the cationic softeners, usually quaternary ammonium halides, have therefore been replaced with smectite clays which have softening properties, e.g. the swelling bentonites. It has been shown that such softening detergents satisfactorily wash soiled laundry and improve the softness of the laundry. However, it has also been shown that the best softening effect is achieved when the laundry is machine washed and that less softening effect is obtained when the laundry is hand washed.

Insoluble metal stearates, such as aluminum stearate or calcium stearate, have been used as lubricants and have been incorporated into detergents because of their fabric softening properties. Before the present invention, however, swelling bentonites and insoluble soaps were not used together in constructed, synthetic, organic grow ash agents or in connection with such detergents for hand washing clothes. The surprisingly favorable effect obtained by using such a combination of materials was therefore previously unknown.

The invention thus relates to a particulate, fabric-softening detergent mixture, particularly suitable for hand washing clothes, comprising 5-35% by weight synthetic organic surfactant selected from the group consisting of anionic and non-ionic surfactants, 5-75% by weight building salt for the surfactant, 2- 30% by weight of bentonite and 0.5-20% by weight of soap, and the detergent mixture is characterized by the fact that the soap is an aluminum soap of fatty acids with 8-20 carbon atoms or a mixture of such an aluminum soap with one or more other water-insoluble soaps of such fatty acids.

The bentonite is preferably a swelling sodium bentonite, such as Wyoming bentonite, and the soap is preferably aluminum stearate.

The required detergent compositions lead to greatly improved softening of hand-washed laundry, and this improvement is surprising.

The detergent according to the invention, which includes bentonite and aluminum soap, can be any of a number of different types and can be made in a number of different ways. It is most preferred to agglomerate the bentonite by forming a particulate material that can be added to built-up, synthetic, organic detergent particles for rough wash or full wash so that the built-up detergent acquires fabric softening properties. This improvement is particularly beneficial when clothes are to be washed by hand with the detergent.

The built detergent beads with which such bentonite agglomerates and aluminum soap can be mixed can be spray-dried beads that usually contain an anionic, synthetic, organic surfactant, builder salt, adjuvants and a minor amount of moisture, and they occasionally contain a nonionic and/or amphoteric surfactant instead of or in addition to the anionic surfactant. Alternatively, spray-dried, inorganic building base material beads will be provided with a non-ionic surfactant that has been sprayed onto them in a liquid state and absorbed by them. Both of these types of built detergent particles may be provided with powdered bentonite and aluminum soap that has been agglomerated on their surfaces, and in some cases the built detergent particles may be mixed with powdered bentonite and insoluble soap.

As indicated above, the essential ingredients in builder synthetic organic detergent beads or granules include a synthetic organic surfactant which may be an anionic surfactant, a nonionic surfactant, an amphoteric surfactant or a mixture of two or more of these, a builder or a mixture of builders and a smaller amount of moisture although various auxiliaries as well

in a number of cases may be present. Incidentally, such auxiliary additives can also be present together with mixtures of bentonite and insoluble soap. Occasionally, in both of the aforementioned cases, the builder may be partially replaced with a filler, such as sodium sulfate or sodium chloride or a mixture thereof, or such a filler may be added to the builder and the synthetic organic surfactant.

Various anionic surfactants, usually in the form of sodium salts, but occasionally in the form of potassium, ammonium or alkanolammonium salts, can be used, but those that are most preferred are the sodium linear-higher-alkylbenzene sulphonates. Although the linear sulfonates are preferred, the branched ABS surfactants can also be used, such as the propylene tetramer or propylene pentamer compounds. Other soluble alkylbenzene sulfonates, such as those having 10 or 12-18 carbon atoms, can also be used and will act satisfactorily as surfactants. The higher alkyl group preferably has 12-15 carbon atoms, e.g. 12 or 13 carbon atoms, and the salt is a sodium salt. Higher alkyl sulfates and higher fatty alcohol polyethoxylate sulfates can also be used in addition to the alkylbenzene sulfonates or as a replacement for the entire amount or part of these. The alkyl sulfate is preferably a higher fatty alkyl sulfate with

10 - 18, preferably 12 - 16, e.g. 12, carbon atoms and is also used as the sodium salt. The higher alkylethoxamer sulfates will similarly have 10 or 12-18 carbon atoms, e.g. 12 carbon atoms, in the higher alkyl group which will preferably consist of a fatty alkyl group, and the ethoxy content will normally be 3-30, preferably 3 or 5 - 20, ethoxy groups per molecule. Again, the sodium salts are preferred.

It will thus appear that the alkyl groups are preferably linear or higher fatty alkyl groups with 10 - 18 carbon atoms, and that the cation is preferably sodium, and when a polyethoxy chain is present, the sulfate will be at the end of this. Other useful anionic surfactants of this sulfonate and sulfate group include the higher olefin sulfonates and paraffin sulfonate, e.g. the sodium salts in which the olefin or paraffin groups have 10 - 18 carbon atoms. Specific examples of the preferred surfactants are sodium tridecylbenzene sulfonate, sodium tallow alcohol polyethoxy (3 EtO) sulfate or sodium hydrogenated tallow alcohol sulfate. In addition to the mentioned preferred anionic surfactants, others within this well-known group may also be present, especially only in smaller proportions compared to those described above. Moreover, mixtures of these can be used, and in some cases such mixtures can prove to be superior in relation to the use of single surfactants. The various useful surfactants are well known in the art and are extensively described on pages 25-138 of the textbook Surface Active Agents and Detergents, Vol. II, by Schwartz, Perry and Berch, published

in 1958 a^- Interscience Publishers, Inc.

Small amounts of water-soluble soaps, e.g. sodium soaps of fatty acids with 10 - 24, preferably 14 - 18, carbon atoms, e.g. sodium hydrogenated tallow fatty acid soaps,

carbon atoms, e.g. sodium-hydrogenated tallow-fatty acid soaps can be used in the kneading machine ("crutcher") or added afterwards as foam control agents if less foam is desired in the washing machine.

Although various nonionic surfactants with satisfactory physical properties may be used, including condensation products of ethylene oxide and propylene oxide with each other and with hydroxide-containing bases, such as nonylphenol and oxo-type alcohols, it is strongly preferred that the nonionic surfactant be a condensation product of ethylene oxide and higher fatty alcohol. In such products, the higher fatty alcohol has 10-20 carbon atoms, preferably 12-16 carbon atoms, and the non-ionic surfactant contains 3-20 or 30, preferably 6-12, ethylene oxide groups per molecule. The non-ionic surfactant will most preferably be a surfactant in which the higher fatty alcohol has 12 - 13 or 15 carbon atoms and which contains 6-7 or 11 molecules of ethylene oxide. Such surfactants are available on the market under the trademark Neodo]® with the quality designations 23-6.5 and 25-7. Among their particularly appealing properties, apart from good washing power against oil-like stains on items to be washed, is a relatively low melting point which is nevertheless considerably higher than room temperature, so that they can be sprayed onto the base beads in the form of a liquid that solidifies. Among the amphoteric surfactants can be mentioned the commercial products sold under the trademark Miranol®, e.g. with the quality designations C2M, CM, DM or

DS.

The water-soluble builder used can be made up of one or more of the usual materials that have been used as builders or proposed for this purpose. These include inorganic and organic builders and mixtures thereof. Among the inorganic builders, the preferred ones are the various phosphates, preferably polyphosphate, e.g. tripolyphosphates or pyrophosphates, such as pentasodium tripolyphosphate and tetrasodium pyrophosphate. Trisodium nitrile triacetate (NTA), preferably used as the monohydrate, or other nitrile triacetates, such as disodium nitrile triacetate, are also good water-soluble builders. Sodium tripolyphosphate, sodium pyrophosphate and NTA are preferably present in hydrated form. Of course, carbonates, such as sodium carbonate, are good builders and can, if desired, be used alone or together with bicarbonates, such as sodium bicarbonate. Other water-soluble builders considered effective include the various other inorganic and organic phosphates, borates, e.g. borax, citrates, gluconates, EDTA and iminodiacetates. The various builders will preferably be present in the form of their alkali metal salts, either as the sodium salt or the potassium salt or a mixture thereof, but sodium salts are normally more preferred. Sodium silicates with a ratio Na-jOrSiC^ within of bentonite. Sodium silicate also contributes to the detergent having anti-corrosive properties, which is important if the detergent is to be used in contact with aluminum or other metals that are exposed to corrosion attack.

In addition to the aforementioned water-soluble builders, water-insoluble builders can also be used, such as the zeolites. These materials will normally have the formula

in which x is 1, y is 8.0 - 1.2, preferably approx. 1, z 1.5 - 3.5, preferably 2, .3 or approx. 2, and w 0 - 9, preferably 2.5 - 6.

The zeolite should be a monovalent cation exchange zeolite, ie it should be an aluminum silicate with a monovalent cation, such as sodium, potassium, lithium (if practical) or another alkali metal or ammonium cation.

The monovalent cation for the zeolite molecular sieve is preferably an alkali metal cation, especially sodium or potassium cation, and it is most preferably sodium cation. The most preferred of the zeolites are those designated by A,

X, Y, the type 4A being preferred. Preferred zeolites are those which are hydrated to a degree of 5 - 30, preferably 15 - 25, % moisture content, especially if they have good calcium ion exchange properties of preferably over 200 mg equivalents of calcium carbonate per gram.

Various auxiliary additives can be present in the slurry from which the detergents or base beads are sprayed, or such auxiliary additives can be added afterwards, as the determination regarding the method of addition is often determined by the auxiliary additive's physical properties, its heat resistance, its resistance to degradation in the aqueous slurry and its volatility . Although some adjuvants,

as fluorescent whitener, pigment, e.g. ultramarine blue, titanium dioxide or 'inorganic' filler salt, can be added in the kneading device ("crutcher"), other auxiliary additives, such as perfumes, enzymes, bleaching agents, certain coloring materials, bactericides, fungicides or fluidity control

demanding agents, often sprayed on or otherwise mixed with the base beads or with the spray

dried detergent together with an optional

non-ionic surfactant to be added, and/or independently, so that they will not be adversely affected by the elevated temperatures of the spray-drying process, and also so that the presence of these in the spray-dried beads will not inhibit the absorption of the - ionic surfactant if such is to be subsequently sprayed on the beads. For stable and normally solid auxiliary additives, it is usually suitable to mix these into the output slurry in the kneader. The aim is thus that any pigments and fluorescent white roids used should normally be present in the slurry from which the detergent or base beads are sprayed. If a possible cationic softening agent, such as a quaternary ammonium compound, e.g. cetyltrimethylammonium bromide or di-stearyldimethylammonium methylsulphate, should be present, it is best to add this afterwards.

The bentonite used is a colloidal clay (aluminium silicate) containing montmorillonite. Mont-morollonite is a hydrated aluminum silicate in which approx. 1/6 of the aluminum atoms can be replaced by magnesium atoms and with which varying amounts of sodium, potassium, calcium, magnesium and other metals, and hydrogen, can be loosely combined. The type of bentonite clay most useful for the production of agglomerated bentonite particles is that known as sodium bentonite (or Wyoming or "western" bentonite) which is normally a light to cream-colored, insensible powder which in water forms a colloidal suspension with strong thixotropic properties. In water, the swelling ability of the clay will generally lie within the range 3-20, preferably 7-15, ml/g, and its viscosity measured for a 6% concentration in water will generally lie within the range 3-30, preferably 8-30, centipoise. Preferred swelling bentonites of this type are sold under the trade name "Mineral Colloid" as industrial bentonites, and under the trade name "Volclay Special Purpose Powder". The "Mineral Colloid" type clays are the same as those formerly sold under the trade name "THIXO-JEL" and are selectively mined and enriched bentonites, and those considered the most useful are commercially available under the trade name " Mineral Collid" no. 101 etc. corresponding to "THIXO-JEL" no. 1, 2, 3 or 4. Such materials have a pH (for a 6% concentration in water) of 8 - 9.4, a maximum free moisture content of approx. 8% and a specific weight of approx. 2.6, and for the powdered grade at least 85% (preferably 100%) will pass through a 74 µm sieve. bento-

nineteen is more preferred than bentonite in which essentially all particles (over 90%, preferably over 95%) pass through a 44 µm sieve, and it is most preferred that over 99% or all of the particles pass through such a sieve. "Western" or Wyoming bentonite is preferred as an ingredient in the present detergents, but other swelling bentonites may also be used, especially if they constitute only a minor portion of the bentonite used.

Although, as mentioned, it is desirable to limit the maximum free moisture content, it is even more important to make sure that the bentonite used contains sufficient free moisture, as most of this is assumed to be present between neighboring plates in the bentonite, to promote rapid breakdown of the agglomerates of bentonite, when such particles or detergents containing them are brought into contact with water, such as washing water. It has been found that at least 2, preferably at least 3, and more preferably at least 4,% or more of water should be present in the bentonite to begin with before it is agglomerated, and such an amount should also be present after any drying. In other words, overdrying to the stage where the bentonite loses its "internal" moisture can significantly reduce the applicability of the present materials. When the bentonite moisture content is too low, the bentonite will not satisfactorily help with the breakdown of the agglomerate in the wash water. When the bentonite has a satisfactory moisture content, it can have an effective exchangeable calcium oxide percentage within the range of 1 - 1.8, and in the case of magnesium oxide this percentage will often

lie within the range 0.04 - 0.41. A typical chemical analysis for such a material is 62 - 73% SiO2, 14 - 22% A12O3/

1.6 - 2.9% MgO, 0.5 - 3.1% CaO, 2.3 - 3.5% Fe2O3, 0.8 -

2.8% N<a>20 and 0.4 - 7.0% K20.

Instead of using the "THIXO-JEL" or "Mineral Colloid" bentonites, equivalent competitive products can also be used, such as that sold under the name "General Purpose Bentonite Powder", 325 mesh, which contains at least 95% particles that are finer than 325 mesh or finer than equivalent to a diameter of 44 ym (wet particle size) and at least 96% particles finer than 3:nn 2/00 mesh or equivalent to a diameter of 74 ym (dry particle size ). Such a hydrated aluminum silicate is basically made up of montmorillonite (at least 90%) with smaller amounts of feldspar, biotite and selenite. A typical analysis on an "anhydrous" basis is 6 3.0% silicon dioxide, 21.5% aluminum oxide, 3.3% trivalent iron (as Fe2O3), 0.4% divalent iron (as FeO), 2.7% magnesium ( as MgO), 2.6% sodium and potassium (as Na-,0), 0.7% calcium (as CaO), 5.6% crystal water (as H2O) and 0.7% trace elements.

Although the "western" bentonites are preferred, it is also possible to use synthetic bentonites, such as can be made by treating Italian or similar bentonites containing relatively small proportions of exchangeable monovalent metals (sodium and potassium), with alkaline materials, such as sodium carbonate, to increase the products' calcium ion exchange properties. An analysis of a typical Italian bentonite after alkaline treatment suggests that it contains 66.2% SiO2, 17.9% A<l>2<0>3, 2.80% MgO, 2.43% Na2O, 1.26% Fe 2 O 3 , 1.15% CaO, 0.14% TiO 2 and 0.13% K 2 O, on a dry basis. It is assumed that the Na20 content in the bentonite should be the least

0.5, preferably at least 1, and more preferably at least 2.%

(while the equivalent proportion of K20 has also been taken into account), so that the clay will be satisfactorily swelling and with good softening and dispersing properties in aqueous suspensions to achieve the purpose of the present

invention. Preferred swelling bentonites of the described synthetic types are sold under the trade names "Laviosa"

and "Winkelmann", e.g. "Laviosa AGB" or "Winkelmann G13". Other clays that may be used include those sold under the trade names "rock", "Volclay BC", "Gel White GP", "Ben-A-Gel", "Veegum F", Laponite^SP or "Barasym LIH 200".

The binder that can be used to help with

holding the finely divided bentonite particles together in agglomerated form is preferably a sodium silicate, such as has previously been described as a builder. Instead of silicate, other binders can be used, such as the natural and synthetic rubbers, e.g. xanthan, carrageenan, guar,

CMC, PVA and PVP, which may also exhibit desired adjuvant effects. Although binders are useful,

in some cases showering with water alone will be able to produce a sufficient bonding effect.

The water-insoluble soaps used for the production of the products according to the invention always comprise aluminum soap and have 8-20, preferably 19 or 12-18, and most preferably 18, carbon atoms and are preferably saturated.

Among such soaps can be mentioned the octoates, decanoates, laurates, myristates, palmitates, oleates (unsaturated)

or the stearates of aluminum which can possibly be used together with the corresponding calcium, magnesium, barium

or zinc soaps or mixtures thereof. Such soaps are usually produced by the melting method or by the precipitation method. In the first of these, a suitable metal oxide, hydroxide or salt of a weak acid is reacted directly with the selected fatty acid at an elevated temperature. In the precipitation method, a dilute solution of dissolving soap is first prepared by reacting sodium hydroxide with the selected fatty acid, and the solution is then reacted with a separately prepared salt solution of the desired metal to effect refinement of the metal soap. The described soaps are normally sufficiently finely divided that essentially all of their particles will pass through a 74-inch sieve and in a number of cases (e.g. over 95 or 99% of the particles) through a

44yUm term. Under suitable circumstances, however, a somewhat coarser powder can also be used, such as a powder with particles that pass through a 149 µm sieve, but generally the more finely divided, but generally the more finely divided the powder is, the better. Such soaps will normally contain very small amounts, or none, of water-soluble salts.

ter or moisture, and they will all be powdery solids at room temperature. All of the soaps mentioned are white so that they will not adversely affect the appearance of the washing medium. In fact, they can help improve the color of the bentonite which, although normally white, occasionally tends to appear light brown or cream. It should be noted that the various aluminum soaps can have a higher free fatty acid content than the calcium, magnesium, barium and zinc soaps, with the free fatty acid content varying from 2 to 30%. However, this content does not affect the functioning of such materials in the present detergents. As for the aluminum soaps, the di- or tri-salt can be used, e.g. aluminum distearate or aluminum tristearate, but a mixture of such soaps is considered preferred in which the quantity ratio between these will lie within the range 1:3 - 3:1, e.g. about. 1:1. Other incompletely reacted, insoluble soaps of the other mentioned metals (and aluminium) and of bi- or polyvalent metals and fully reacted soaps thereof may be used together with aluminum soap in different relative amounts, and mixtures of the various soaps together with aluminum soap may also be used .

The various water-insoluble soaps mentioned are described in a brochure entitled Witco Metallic Stearates, Their Properties and Uses, September 1974, published by Witco Chemical Corporation, New York, New York 10017.

The water used in the production of slurries from which the base beads or built-up detergent beads are spray-dried and for the production of agglomeration showers preferably has low hardness and a content of inorganic salts, but ordinary tap water can be used.

As a rule, the hardness content of such water will be below 300 ppm, calculated as calcium carbonate, preferably below 150 ppm, and preferably below 50 or 100 ppm.

In the particulate, fabric-softening detergent according to the invention, the synthetic, organic surfactant component will be used in a sufficient quantity to exert satisfactory washing power on clothes when the detergent is used in the normal washing water concentrations. Thus, 5-35, preferably 10-25, more preferably 12-22, e.g. 17.% (on a final product basis) of the synthetic organic surfactant is used. Although sodium linear tridecyl benzene sulfonate is a preferred anionic surfactant, it will be understood that other surfactants and mixtures thereof may be used. In those cases where a non-ionic surfactant is used which can be sprayed onto previously prepared base beads of inorganic building salt, the more preferred amounts can be 15 - 22 or 25, e.g. 20, %. The total amount of building salt present in the detergent will be such that the synthetic, organic surfactant will be satisfactorily built and thereby made more effective. Such a quantity is

5-75, preferably 20-60, and most preferably 40-50, %. When sodium tripolyphosphate is the main building salt present, the amount of this will preferably be 10-50, more preferably 20-30, e.g. about. 24.%. When sodium carbonate and sodium silicate are the other main builders present, the amounts of these will normally be 2-20, preferably 10-15, % of the carbonate and 2-12, preferably 6-10, % of the silicate, e.g. . 12% and 8%.

The bentonite content in the final detergent is 2-30, preferably 5-30, and more preferably 8-25, approx. 18%. The content of soluble soap is 0.5-20, preferably 0.5-15,

and more preferably 1-5, e.g. about. 2.%. The moisture content will normally be 3-15, preferably 7-12, e.g. about. 10.%. When a filler is present (and such a filler salt may be replaced by auxiliary additives and builders), the amount of this will usually be 0-40, preferably 5-25, e.g. about. 8.%.

The bentonite and water-insoluble aluminum soap, possibly in a mixture with other water-insoluble soaps of a divalent or multivalent metal, can be present as powder, agglomerated bentonite with separated insoluble soap powder, or bentonite and insoluble soap agglomerated on surfactant beads. -

The described bentonite agglomerates, which can be produced and stored and are ready for addition to different types of detergents, are preferably produced using the method and equipment described in US patent no. 4488972. In such a method, bentonite is kept in motion, e.g. e.g. by tumbling in an inclined drum equipped with a series of break-up bars, so that the particles are in continuous motion and form a "screen"

(which is usually falling) against which a shower of agglomeration liquid can be directed. The agglomeration liquid used may consist of water alone, but occasionally, and preferably, the liquid will contain a suitable binder,

like for example. a binder which has been described above, together with auxiliary additives, such as a coloring material etc, and it will be directed towards the surfaces of bentonite which is kept in motion, the spraying and movement of the particles being regulated so that agglomerates are obtained within the desired size range from a 2 .00 mm sieve to a 149 µm sieve, preferably from a 595 µm sieve to a 149 µm sieve,

and more preferably a 420 µm sieve to a 149 µm sieve or from a 420 µm sieve to a 177 µm sieve. When the desired size and uniformly shaped agglomerated product has been produced (with a desired bulk density which is often within the range of 0.7-0.9 g/ml), the agglomeration is stopped and, if desired, the beads are dried to a suitable moisture content, e.g. e.g. 10%

(which is approximately equal to the equilibrium moisture content in the bentonite), and as desired they are sieved and stored for use as an additive to the detergent beads. The solids content in the aqueous shower of binder, if such is used, is as a rule 2-20, preferably 4-10, and more preferably 6-9, e.g. 7.5%, and the moisture content of the agglomerated particles before drying will often be 20-35, e.g. about. 25.%.

Thus, when such a higher moisture content in the agglomerates is obtained, it will be desired to dry them, but this does not mean that smaller amounts of moisture cannot be added during the agglomeration, so that drying can be avoided. It will often be preferable for the agglomeration shower to have an elevated temperature, such as e.g. within the range 50 - 90, preferably 60 - 80, °C, and the shower will advantageously be provided by using a shower nozzle which is constructed in such a way that it emits a fine, flat shower pattern which will be directed transversely in relation to the screen of particles formed in the agglomerator.

It is also possible to agglomerate each of the bentonite and the insoluble soap or both (preferably both) materials onto the detergent beads or base beads,

e.g. using the method described in US Patent No. 44,8972. The saran type of dousing solution and essentially the same type of mixing apparatus are used, but the bentonite and insoluble soap are agglomerated on the surface of the spray dried beads. According to another embodiment of the described method, the bentonite and the insoluble soap can be agglomerated on detergent beads in a higher concentration than desired for the final product, and such agglomerates can then be mixed with more detergent beads. In such agglomeration methods, it may in some cases, although it is strongly preferable to use a binder, and silicate is preferred because it is effective and can be used as a detergent builder, it may be possible to loop the binder and effect the agglomeration using water alone or water and another suitable solvent or liquid agent.

For machine washing and softening of clothes, the concentration of the built-in, synthetic, organic coarse or full detergent used in the washing water will usually be 0.05 - 0.5%. The concentration will preferably be 0.07 - 0.2, more preferably 0.15% for top-loading washing machines, in accordance with American practice, and for side-loading machines approximately half of this percentage will often be used. According to European practice, where washing water with a higher temperature is usually used and the detergent concentrations are generally greater, the concentration can be 0.2 - 0.6, e.g. 0.4%. For hand washing-softening of laundry where smaller washing tubs than washing machine cylinders can be used, the concentration of the detergent can be 0.2 - 1, preferably 0.3-0.7, %. The stated figures apply without the bentonite agglomerate being taken into account. The concentration of bentonite present in the various washing waters will be 0.05 - 0.3, preferably 0.03 - 0.2, and most preferably 0.06 - 0.14, % (the latter range applies to hand washing ). The concentration of insoluble soap will be 0.001 - 0.2, preferably 0.003 - 0.02, and most preferably (for hand washing) 0.006 - 0.014%. The concentrations of available detergents in the wash water will usually be 0.06 - 1.4, preferably 0.1 - 1.0, and most preferred (for hand washing)

0.4 - 0.9%.

It has been shown that in hard water some insoluble soap can be formed due to reaction between water-soluble soaps (if such are present) and hardness-promoting cations in the water, but even if such insoluble soaps "formed in situ" can help in improving the softening effect of the bentonite in the present media, especially when washing clothes by hand, they are not as satisfactory as the insoluble soaps added to the detergent. Moreover, detergents must be able to be used in water of all degrees of hardness, and it cannot be trusted that sufficient hardness will always be present in the used washing water to provide the desired proportion and type of insoluble soap to satisfactorily soften the laundry.

Although the products according to the invention are free-flowing, attractive, non-segregating^ effective detergents which soften the fabric of clothes washed with them, whereby the need to add a separate softening material to the rinse water is avoided, and although the products are excellently satisfactory as detergents and fabric softeners, the main advantage obtained by the present invention is due to the softening ability when washing clothes by hand. Although automatic washing machines are widely used and investigations of the properties of laundry detergents are usually carried out in them, a number of consumers throughout the world, including some in the "developed" or industrialized countries, wash their clothes by hand. It has been shown that such hand washing of clothes does not lead to good softening when bentonite is incorporated into detergents, regardless of whether the bentonite has been spray-dried together with the detergent or agglomerated and subsequently added. Various theories have been put forward as to why this minor softening effect of bentonite in detergents used for hand washing clothes occurs. According to such a theory, in the normal washing machine, the washing water is drawn through the laundry when the cylinder is emptied, whereby the bentonite is brought into intimate contact with the laundry, which acts as a filter and holds the bentonite particles. When washing by hand, on the other hand, this "silting" effect will not occur, and therefore not as much bentonite will be retained by the laundry. According to this theory, due to a mechanism that has not been clarified, the insoluble soap will help attract the bentonite to the fibers of the fabric. Although the proposed theory is apparently valid, it will be understood that it is not intended to be bound by it. Regardless of which explanation is the correct one, it has been shown that the combination of insoluble soap and bentonite gives greatly improved softening when detergents containing such combinations are used. Such products are also satisfactory for machine washing, but in such applications there is a relatively small difference in the softening effect between the use of the bentonite alone and the bentonite together with the insoluble soap. An embodiment of the product according to the invention in the form of a piece or cake with the compositions described above and occasionally with 10 - 70% of the content of synthetic, organic surfactant replaced with sodium-higher-fatty-acid soap, preferably a mixture of coconut oil - and hydrogenated tallow soaps, will be particularly beneficial for hand washing clothes, and in some cases such a piece or such a cake can be combined with a sponge or foam plastic surface, such as e.g. described in US patent 4,203,857, in order to achieve the best application properties. Suitable plasticizers and/or binders, such as soaps, higher fatty acids and/or natural and synthetic organic gums may be present, and the pieces

or the cakes can be produced by extrusion, punching and/or pressing.

The invention is described in more detail in the examples below. If nothing else is stated, in the examples and in the description otherwise all temperatures are stated in °C and all parts and percentages are based on weight.

Example 1

Detergent beads of the above composition and a particle size within the range of 2.00 mm to 149 µm (sieve No. 10 to sieve No. 100 (U.S. sieve series)) are produced by spray drying a 50% aqueous slurry of the various components, apart from the perfume, using a normal countercurrent spray tower and normal drying conditions. The perfume is subsequently added to the dried detergent beads, whereby these are cooled to approximately room temperature, by spraying the perfume onto the surface of the beads while they are being mixed.

In a common mixer for detergent products, such as a Day mixer, in which the mixing blades move at a relatively low speed so as not to reduce the size of the detergent and bentonite agglomerate beads, 10 parts of the detergent beads and 2.8 parts of the aggregate are agglomerated

beads of swelling bentonite, and aluminum stearate in the same

quantities by weight mixed with each other. Such a mixture thus contains 10 parts detergent, 1.25 parts swelling bentonite and 1.25 parts aluminum stearate, plus water and silicate bentonite in the agglomerate beads.

The softening detergent containing the bentonite and aluminum stearate is added to washing water at a temperature of 25°C and a hardness calculated as calcium carbonate

(actually mixed calcium and magnesium hardness in a ratio of about 2:1), of 100 ppm, up to a concentration of 3.6 g per litres, and the laundry, including items made of cotton, polyester and cotton/polyester blends, is washed by hand, rinsed and dried on a drying line in the open air. After drying, a group of trained experts assess the softness of the fabric and find it to be very acceptable. With similar experiments where half the concentration of softening detergent is used, a smaller, but still useful and desired, is noted,

degree of softening. The softened detergent is free-flowing and has an attractive appearance and satisfactorily removes clay as well as oil-like (skin grease) dirt from normal laundry and sample laundry that is washed with it. As a blank test, a softening detergent containing 4 parts of the detergent described here and 1 part of the bentonite agglomerate in the same concentration is used, and the same method is followed. The expert group finds that although laundry washed with such detergents is softer than laundry washed only with the detergent portion, it is not as soft as laundry that has been washed in a comparative manner with the product according to the invention which contains approx. 10% of both the bentonite and the aluminum stearate. When, moreover, 20% aluminum stearate replaces the 20% bentonite used in the described blind test product and the same treatment and evaluation method is followed, the observed softening effect on the laundry is less than that obtained with the aforementioned product according to the invention.

When other aluminum soaps, such as aluminum palmitate, aluminum myristate or aluminum laurate, are used instead of the aluminum stearate and which all consist of approximately equal mixtures of the di- and trialkanolates, similar results are obtained. This is also the case with the corresponding oleate with mixtures of the soaps, such as e.g. mixtures of the stearate and oleate, mixtures of the laurate and myristate or mixtures of laurate, myristate, palmintate, oleate and stearate. When

soaps of calcium, magnesium, barium and zinc are used instead of aluminum soaps in all the experiments described above, results are obtained which show that none of the other soaps are as effective as the aluminum soaps.

Similar results to those described above are obtained when the mixtures of detergent and fabric softener bentonite and aluminum soap are pressed into pieces, cakes or briquettes or incorporated into sponge-surfaced detergent cakes, and when the pieces are used to rub against the more soiled areas of the laundry, such as collars or cuffs, better cleaning and softening is noted for such previously soiled areas. In such pieces, various plasticizing components can also be present, such as e.g. 10% sodium soaps of the final product, e.g. sodium stearate, or of a plasticizer, such as a higher fatty alcohol, e.g. ethyl alcohol, or a higher fatty acid, e.g. stearic acid, or mixed cocus and hydrogenated tallow fatty acids. Alternatively, part of the insoluble soap in the fabric softening detergent can be replaced with one or more water-soluble aluminium, calcium, magnesium, barium or zinc salts, e.g. aluminum sulphate, calcium chloride, magnesium sulphate, barium chloride or zinc chloride, and only a part, e.g.

10 or 50%, of the insoluble soap will be replaced with

soluble soap capable of forming such an insoluble soap "in situ".

Example 2

In order for washing conditions to be accurately reproduced in order to obtain comparative data for the softening effect obtained with the fabric softening detergents according to the invention and the washing softening processes, a laboratory method is carefully followed, and this gives comparative results for hand washing. In such a method, the _recipe quantities of detergent, swelling bentonite ('Mineral Collid" No. 101) and water-insoluble soap are added to a 4 liter beaker containing 1 liter of water (100 ppm hardness, calculated as CaCO^) at 25° C. A terry towel (face cloth size) is placed in the water and the towel and the water containing the detergent are agitated for 30 seconds, then the towel is soaked: for 10 minutes and then hand washed for another 30 seconds The towel is then rinsed in 1 liter of water and dried on a line.

When the detergent is that described in example 1 and its concentration is 2.8 g/l (no bentonite and no insoluble soap is present), a group of experts who use a scale of 1 -r 10 to describe increasing degree of softness, the hand-washed and line-dried terry towel to have a softness number of only 1. When the same method is repeated, but with 0.7 g/l of "Mineral Colloid" No. 101 in agglomerated or powdered form also present in the wash water, the softness number increases to 5. However, when the same experiment is carried out, but 0.35 g/l of the swelling bentonite and 0.35 g/l aluminum stearate are present as separate added powders, together with the same concentration of the detergent, the softness figure increases to respectively 8, 6 and 6. Similar results can be obtained with corresponding laurates, myristates, palmitates, oleates, mixtures thereof or mixtures of such aluminum soaps of mixed coconut and hydrogenated tallow fatty acids. Similar results can also be obtained when the concentrations of the mixtures of bentonite and aluminum soap are halved and reduced to a third, the softness figures being lower, but still better than the softness figures when using the bentonite alone at the double "softener" concentration. When the concentration of bentonite and aluminum soap is increased by half or doubled, a further improvement in softening is obtained. Such results are also obtained when the bentonite concentration is varied to 0.35 or 0.8 g/l and the content of aluminum soap is reduced to 0.07 to 0.18 g/l.

When similar tests are carried out with 2.8 g/l of the detergent present in the wash water together with 0.7 g/l aluminum stearate, but without bentonite present, softness figures of respectively 4, 1 and 3 for the recipes containing aluminum stearate alone or in a mixture with calcium stearate and barium stearate. The same comparison results of detergent and softening additives in the wash water are reduced to half and a third or increased accordingly.

The above results show that a surprisingly favorable improvement in fabric softening is obtained when swelling bentonite and water-insoluble soap comprising aluminum soap are incorporated into a fabric softening detergent.

Example 3

The procedure according to example 2 is followed, except that only aluminum stearate is used and in lower concentrations, and that clothes washed with detergents contain bentonite and such aluminum soap is judged directly in relation to clothes washed with detergents containing double the bentonite concentration and no aluminum soap. In test A according to this example, the concentration of the detergent base material is thus 2.8 g/l and of the bentonite agglomerate 0.7 g/l. In experiment B, the same concentration is used

of detergent, the bentonite concentration is reduced to 0.35 g/l, and 0.18 g/l aluminum stearate is also present.

A group of seven experts compared the softness of towels washed with product A compared to towels of the same type washed with product B. All seven experts preferred product B over product A in terms of softness. Similar results are obtained when a mixture of 0.09 g/l aluminum stearate and 0.09 g/l calcium stearate is used instead of the 0.18 g/l aluminum soap.

Similar comparative results are obtained when experiments A and B are repeated, but with 0.07 g/l aluminum stearate instead of the previously used concentrations of 0.18 g/l.

Results similar to those reported in this example are obtained regardless of whether the bentonite and the aluminum soap are in the form of a powder or whether one of these is agglomerated and the other is present as a powder. Such results can also be obtained when the insoluble soap is spray-dried together with the rest of the detergent, except for the bentonite which is preferably agglomerated. In some cases, the bentonite can also be present in the spray-dried mixture, but care must then be taken to prevent excessive hydration of this.

Claims (6)

1. Particulate, fabric softening detergent mixture, particularly suitable for hand washing clothes, comprising 5-35% by weight synthetic organic surfactant selected from the group consisting of anionic and non-ionic surfactants, 5-75% by weight building salt for the surfactant, 2-30% by weight bentonite and 0.5-20% by weight soap, characterized by the soap being an aluminum soap of fatty acid with 8-20 carbon atoms or a mixture of such an aluminum soap with one or more other water-insoluble soaps of such fatty acids. 2. Detergent mixture according to claim 1, characterized in that at least part of the mixture is spray-dried and that the bentonite is a swelling bentonite which is present as particles separated from the spray-dried part of the detergent mixture. 3. Detergent mixture according to claim 2, characterized in that the bentonite is agglomerated into particles with a size equal to the size of the particles of the spray-dried part of the detergent mixture. 4. Detergent mixture according to claims 1-3, comprising 10-25% by weight synthetic anionic organic surfactant, 10-50% by weight of a phosphate builder for such a surfactant, 5-30% by weight swelling bentonite, 0-40% by weight filler salt and 3- 15% by weight of water, characterized in that it contains 0.5-15% by weight of aluminum soap. 5. Detergent mixture according to claim 4, in which the anionic surfactant is higher alkylbenzene sulfonate in which the higher alkyl group has 12-18 carbon atoms, the phosphate is sodium tripolyphosphate, the bentonite is a sodium bentonite, and the filler salt is sodium sulfate, characterized in that the aluminum soap is aluminum stearate. 6. Detergent mixture according to claim 5, in which the alkyl-benzenesulfonate is selected from the group consisting of sodium linear-dodecylbenzenesulfonate, sodium linear-tridecyl- benzenesulfonate and mixtures thereof and make up 12-22% by weight, the sodium tripolyphosphate makes up 20-30% by weight, the bentonite makes up 8-25% by weight, the sodium sulphate makes up 5-25% by weight, and the water makes up 7-12% by weight, of the mixture comprising 3 -20% by weight sodium carbonate and 2-12% by weight sodium silicate, characterized in that the aluminum stearate constitutes 1-5% by weight of the mixture.