NO153736B - TOYSY DETERGENTS CONTAINING SODIUM CARBONATE, SODIUM BICARBONATE AND WATER-SOILING ZEOLITE IN THE FORM OF SPRAY-DRIED BASED GRAIN - Google Patents

Description

This invention relates to a detergent for washing

of laundry, which has improved washability, and which deposits less residual material on the washed laundry. The new detergent has in common with a previously known type of detergent that it comprises a particulate, structured, synthetic, non-ionic, organic surfactant which is constructed with sodium carbonate, sodium bicarbonate and water-softening zeolite, and that the mixture of sodium carbonate, sodium bicarbonate and zeolite is present in in the form of spray-dried basic grains that are free of synthetic surfactants.

Synthetic organic detergents containing water-softening aluminum silicates, such as zeolites, have been developed and marketed in recent years. In such detergents, which also contain a synthetic organic surfactant or surfactant, the zeolite acts as a sequestering agent for calcium and as a builder for the organic surfactant, which improves the cleaning effect, especially in hard water.

Sodium silicate has also been used in such detergents

as a builder and as an anti-corrosion additive to protect aluminum parts in the washing machine equipment with which aqueous solutions of the detergent come into contact during the washing operations. The silicates can also be useful with regard to counteracting the adverse effects that magnesium ions in the wash water could have on the washing ability of the detergent. Moreover, it is believed that the silicate helps to form more stable detergent grains, especially when these are produced by spray-drying a mixer mixture of detergent components. However, it is well known that zeolites often tend to

to be deposited as a significant residual material on clothes washed in aqueous cleaning agents containing these, and many investigations have shown that the presence of a silicate in such a medium with zeolite increases the amount of deposits.

Benconite, which is a swelling clay with a relatively small ion exchange capacity for components that make the water hard, has been proposed for use in various detergent products, such as soap bars and laundry detergents, where it has often acted primarily as a filler. In some cases, however, bentonite has been claimed to perform other functions. For example, it is stated in US patent no. 4 166 039 that bentonite contributes to the formation of homogeneous detergent slurries, when such slurries contain phosphate or phosphates. Generally, however, the incorporation of clay materials in detergents is avoided, because they are insoluble and can be expected to be deposited on the substances being washed. In fact, clay removal is one of the tests used to judge the effectiveness of detergents. Despite the fact that it could be expected that the addition of bentonite would only worsen the deposit problems when washing clothes with aqueous media containing detergents with a content of zeolite and silicate, it has surprisingly been shown that the deposit decreases. In addition, the binding of calcium ions increases.

Polyacrylates, and often those with a relatively high molecular weight, have been proposed as detergent components.

They have been used as components of washing powders and detergent slurries and have been suggested as substitutes for phosphate builders in non-phosphate containing detergents.

It is known that the polyacrylate has dispersing properties,

and one manufacturer of these materials has proposed their use for dispersing purposes, for example to maintain the suspension of pigments in paints. Furthermore, it is known that in certain aqueous media they inhibit the deposition of insoluble calcium compounds and renewed deposition of insoluble materials on washed laundry. Although polyacrylates have been incorporated into detergents, the present detergents are considered to be new and inventive. The presence of the very small amount of a given type of polyacrylate in the specified detergents, in cooperation with other components of such detergents, has been shown to result in an improved product with better cleaning properties, which can be produced using practical manufacturing operations.

According to the invention, a new detergent is provided, which can be used for washing clothes, and

comprising a particulate, structured, synthetic, nonionic, organic surfactant constructed with sodium carbonate, sodium bicarbonate and water softening zeolite, wherein

the mixture of sodium carbonate, sodium bicarbonate and zeolite is available in the form of spray-dried basic grains that are free of synthetic surfactant. The detergent is characterized in that said mixture contains (a) from 15 to 30% by weight of sodium carbonate, (b) from 10 to 22% by weight of sodium bicarbonate, (c) from 10 to 50% by weight of water-softening zeolite, (d) from 0 to 18% by weight % sodium silicate and (e) from 1 to 20% by weight bentonite and/or from 0.05 to 2% by weight molecular weight polyacrylate

in the range from 1000 to 5000 and that 15 - 30% by weight of a normal solid, non-ionic surfactant has been absorbed in the spray-dried base grains. The presence of the polyacrylate helps to give the base grains more absorption capacity for the liquid, non-ionic surfactant. Often it will also improve spray drying operations and cause less material to adhere to the walls of the dryer and thereby increase the flow rate in the spray drying tower and reduce the number of cleanings of the tower.

The various components of the base grains for the detergent according to the invention will, with the exception of the water, normally be in a solid state, although some of them, when added to the mixer, may be in the form of hydrates or may be dissolved or dispersed in an aqueous medium, such as water. The sodium bicarbonate is anhydrous, and the sodium carbonate is usually used as soda ash. However, the carbonate hydrates, such as the monohydrate, can also be used, if desired, and in certain cases it may be possible to use other carbonates and bicarbonates, such as other alkali metal salts, for example the potassium salts, to replace at least some of the sodium salt, although the sodium salts are strongly preferred. When silicate is present, it is usually added to the mixer as an aqueous solution, which normally has a solids content of from 40 to 50%, for example 47.5%. Preferably this is added towards the end of the mixing process. The silicate used will usually have a ratio of Na20:SiC>2 in the range from 1:1.4 to 1:3, preferably from 1:1.6 to 1:2.4 or 1:2.6 and most preferably from 1 :2 to 1:2.4. Although sodium silicate is the preferred silicate, a portion of the sodium silicate may be replaced with potassium silicate or other suitable soluble alkali metal silicate.

The zeolites used include crystalline, amorphous and mixed crystalline-amorphous zeolites of both natural and synthetic origin, which are satisfactorily fast and effective in counteracting hardness-producing calcium ions in washing water. Preferably, such materials are able to react sufficiently quickly with the calcium ions, so that alone or together with other water-softening compounds in the detergent, they soften the washing water before adverse reactions between such ions and other components of the synthetic, organic detergent take place. The zeolites used can be characterized by having a high exchange capacity for calcium ions, which capacity is usually from 200 to 400 or more milligram equivalents of calcium carbonate hardness per grams of the aluminum silicate, preferably from 250 to 350 milligram equivalents per gram. They also preferably give a residual hardness of from 0.02 to 0.05

mg CaCo3 per liter after one minute, preferably 0.02 to "0.03 mg/liter, and less than 0.01 mg/liter after 10 minutes, all calculated on the basis of anhydrous zeolite.

Although other ion exchange zeolites can also be used, usually the finely divided, synthetic zeolite builder particles used in connection with the invention will have the formula

where c is 1, y is from 0.8 to 1.2, preferably approx. 1, z is from 1.5 to 3.5, preferably from 2 to 3 or approx. 2, and w is from 0 to 9, preferably from 2.5 to 6.

The zeolite should be a monovalent cation exchange zeolite, that is, it should be an aluminum silicate of a monovalent cation, such as sodium, potassium, lithium (when practical) or other alkali metal, ammonium or hydrogen (occasionally). Preferably, the monovalent cation used in the zeolite is an alkali metal cation, especially sodium or potassium and preferably sodium'.

Crystalline zeolite types that can be used as good ion exchangers in connection with the invention include at least partially zeolites of the following crystal structure groups: A, X, Y, L, mordenite and erionite, among which types A, X and Y are preferred. Mixtures of such molecular sil-zeolites can also be used, especially if zeolite of type A is present. These crystalline types of zeolites are well known in the art and are further described in the publication Zeolite Molecular Sieves by Donald W. Breck, published in 1974

by John Wiley & Sons. Typical zeolites of the above structural types found on the market are listed in Table 9.6 on pages 747 - 749 of the above publication by Breck. Such zeolites are known in the art. Certain such zeolites, and likewise other suitable zeolites, have been described in many patent documents in recent years, for use as builders in detergents.

The zeolite used in connection with the invention is usually synthetic, and it is often characteristic in that it has a network of pores of essentially the same size in the range from 3 to 10 Angstroms, the size often being approx. 4 Å (normal). The size is determined solely by the unit structure of the zeolite crystal. Preferably, this is of type A or a similar structure, which is described in more detail on page 133 of the above-mentioned publication. Good results have been obtained by using a molecular sieve zeolite of type 4A, where the zeolite's monovalent cation is sodium, and the zeolite's pore size is approx. 4 Angstroms. Such zeolite molecular sieves are described in US patent no. 2 882 24 3, where they are designated as Zeolite A.

Molecular sieve zeolites can be prepared either in a dehydrated or calcined form, containing from 0 or 1.5% to 3% moisture, or in a hydrated or aqueous form, containing additional bound water in an amount of from 4 to 36% of the total weight of the zeolite, depending on the type of zeolite used. The aqueous hydrated form of the molecular sieve zeolite (preferably from 15 to 70% hydrated) is preferred in the practice of the invention when such a crystalline product is used. The production of such crystals is well known in the art. When producing, for example, Zeolite A, as referred to above, the hydrated zeolite crystals that are formed in the crystal lyse the ionic medium. (such as an anhydrous, amorphous sodium aluminum silicate gel) used without the high-temperature dehydration (calcination to 3% water content or less) normally carried out in the preparation of such crystals for use as catalysts, e.g. cracking catalysts. The crystalline zeolite can, either in fully hydrated form or in partially hydrated form, be recovered by filtering off the crystals from the crystallization medium and drying the crystals in air at ambient temperature, so that the water content is in the range from 5 to 30%, preferably from 10 to 25 %, for example from 17 to 22%. However, the moisture content of the molecular sieve zeolite used can be much lower, as discussed above, in which case the zeolite will usually be hydrated during mixing or other processing.

Preferably, the zeolite should be in a finely divided state, where the particle diameter is up to 20 ym, for example from 0.005 or.0.01 to 20 ym, preferably from 0.01 to 15 ym and most preferably from 0.01 to 8 ym (average particle size ), for example from 3 to 7 or 12 µm, if the zeolite is crystalline, and from 0.01 to 0.1 µm,

for example from 0.01 to 0.05 µm, if the zeolite is amorphous. Although the actual particle sizes are much smaller, usually the zeolite particles will be of a size in the range from 100 to 400 mesh, preferably from 140 to 325 mesh. Zeolites of a smaller size will often become inappropriately dusty, and those of a larger size will not adequately and satisfactorily cover the carbonate-bicarbonate base cores on which they can be deposited during spray drying on a kneading machine mixture to form the base grains.

The bentonite used is a colloidal clay (aluminium silicate) containing montmorillonite. Mont-morillinite is a hydrated aluminum silicate, in which

about. 1/6 of the aluminum atoms can be replaced by magnesium atoms, and with which varying amounts of hydrogen, sodium, potassium, calcium, magnesium and other metals can be loosely connected. The type of bentonite clay described here for making the new base grains is the type known as sodium bentonite (or "Wyoming" or "western" bentonite), which is normally a light cream color,

easily puliver which in water forms a collodal suspension with strongly thixotropic properties. In water, the swelling capacity of the clay will usually be in the range from 3 to 15 ml/g, preferably from

7 to 15 ml/g, and its viscosity, at 6% concentration in water, will generally be in the range of from 3 to 30 centipoise, preferably from 8 to 30 centipoise. Preferred swelling bentonites of this type are those which have been marketed as bentonites for industrial purposes under the trademark "THIXO-JEL"

of the Benton Clay Company, a subsidiary of the Georgia Kaolin Co. Such materials are selectively mined and processed bentonites and those considered to be most useful are those designated "THIXO-JEL" Nos. 1, 2, 3 and 4. These materials have pH value (in 6% concentration in water) in the range from 8 to 9.4, a free moisture content of a maximum of 8%

and specific weight of approx. 2.6, and of the powdery variety passes approx. 85% through a 200 mesh sieve (U.S. Sieve Series). Such materials exhibit a percentage content of exchangeable calcium oxide in the range from 1 to 1.8, while the corresponding percentage content for magnesium oxide is normally in the range from 0.04 to 0.41. Typical chemical analyzes for such materials are 64.8 - 73.0% Si02, 1.4 - 1.8% A12O3, 1.6 -

2.7% MgO, 1.3 - 3.1% CaO, 2.3 - 3.4% Fe2O3, 0.8 - 2.8% Na2O and 0.4 - 7.0% K2O. Although such bentonites are preferred, equivalent materials from other sources can be used instead.

The polyacrylate which is present in preferred base grains in the detergent according to the invention is a low molecular polyacrylate, whose molecular weight is usually in the range from 1000 to 5000, preferably in the range from 1000 to 3000 and most preferably in the range from 1000 to 2000, or approx. 2000. The polyacrylate can be partially neutralized, with for example half or a third being present as Na salt. Although modified polyacrylates can be used instead of the described sodium polyacrylate, including certain other alkali metal polyacrylates and hydroxylated polyacrylates, it is preferred that such replacements be limited to a smaller proportion of the material, and preferably the polyacrylate will consist of an unsubstituted sodium polyacrylate. Such materials are available from Alco Chemical Corporation and marketed under the trade name "Alcosperse". The sodium polyacrylates are obtained as clear, amber liquids or powders, the solutions having a solids content of from 25 to 40%, for example 30%. The pH value of such solutions or of a 30% aqueous solution of the powder is in the range from 7.5 to 9.5, e.g. about. 9. These materials are completely soluble in water and have been used as dispersants. They have been shown to have the ability to bind calcium ions, and they have been used to prevent the excretion of insoluble calcium compounds from aqueous solutions.

The polyacrylate contributes, even in very small amounts,

to improve the mixing of the various blend components, including, in preferred compositions, ultramarine blue which, when poorly distributed, can stain clothes washed with detergent made from the base grains. The polyacrylate also contributes to an even distribution of any fluorescent clarity-enhancing agent present through the kneading machine mixture of the detergent and thereby contributes to the wash having a uniform feel of lightness and clarity. In addition, the polyacrylate makes the final product (with the exception of the content of non-ionic surfactant) more homogeneous. Processing aids that may be present to prevent gelation and separation of the inorganic materials in the mixer during mixing and standing are more uniformly dispersed in the kneader mixture, increasing the efficiency of these materials. The polyacrylate helps to make the base grains formed by spray drying more absorbent

account of the non-ionic surfactant in liquid state that is sprayed onto the grains. In certain cases, it increases the grains' capacity to hold onto the surfactant, while the grains remain free-flowing. Spray drying operations are improved because less of the spray dried material adheres to the walls of the dryer, whereby the material throughput rate in the spray drying tower increases and the number of required cleanings decreases.

The only additional material required for the production of the base grains is water, and during the drying of the grains their moisture content can be reduced to such an extent that the product becomes almost anhydrous. Although it is preferable to use deionized water, so that the content of hardness-promoting ions in the water is very low, and so that the content of metal ions, which can cause the decomposition of any organic materials that may be present in the finished grains and the finished detergents, is as low as possible , ordinary city water or tap water can also be used instead. Usually, the content of hardness-promoting materials in such water will be less than 150 ppm, measured as CaCO^• It is particularly preferred that the content of hardness-promoting materials is less than 100 ppm, and most preferably the content is less than 50 ppm.

Because rather concentrated aqueous kneader mixtures of silicate, carbonate, bicarbonate, zeolite and bentonite and/or polyacrylate can "freeze" in the kneader as a result of mutual reactions between the components of the mixture, if the mixture is kept in the kneader beyond a permissible time, process aids are preferably present in the mixing vessel when silicate is present, and consequently also in the finished base grains and in the finished detergent, to prevent untimely solidification or gelation of the mixture. Ideally, citric acid and magnesium sulphate are used as such processing aids. Instead of citric acid, soluble citrates, such as sodium citrate, can be used, and although it is preferred to use anhydrous magnesium sulfate, various hydrates of magnesium sulfate, such as Epsom salts, can also be used. Likewise, magnesium citrate can be used instead of the above-mentioned materials. Instead of the preferred anti-gel forming system, other means and suitable systems for keeping the kneading machine mixture liquid can be used, for example sodium sesquicarbonate, using instead some of the sodium carbonate and sodium bicarbonate.

Various additives, such as perfumes, enzymes, dyes, bleaches and flow promoters can often be sprayed on or otherwise mixed with the base grains after their manufacture, together with the non-ipnic surfactant or separately, so that they are not adversely affected by the spray drying operation and so that their presence in the spray-dried grains does not inhibit the absorption of nonionic surfactant. However, it is also possible, when stable and normally solid additives are used, to mix these with the slurry of inorganic salts in the kneading machine. It is thus assumed that dyes and fluorescent brightening agents will normally be present in the kneading machine mixture from which the present base grains are formed by spraying and drying. The preferred dye is ultramarine blue, but other stable pigments and dyes can also be used together with this or to replace it. Among the fluorescent brightening agents, the most preferred is "Tinopal 5BM". However, many other brighteners for cotton, such as those often referred to as CC/DAS brighteners, which are formed from the reaction product between cyanuric chloride and the disodium salt of diaminostilbene disulfonic acid, can also be used, including variations of these with regard to the substituents on the triazine ring and the aromatic rings. This class of clarity-promoting agents is known in the detergent trade and will most often be used when bleaching agents are not present in the final product. In such cases, bleach-stable brighteners can be used. Among these can be mentioned the benzidinesulphonic disulphonic acids, the naphthotriazolylstilbensulphonic acids and the benzimidazolyl derivatives. Polyamide-type brighteners, which may also be present, include aminocoumarin or diphenyl-pyrazoline derivatives, and polyester-type brighteners, which may also be used, include naphthotriazolylstilbenes. All such clarifying agents are usually used in the form of their soluble salts, but they can also be added in the form of the corresponding acids. The brightening agents for cotton will usually form a major part of the brightening agent systems.

Among the materials that are added after the production of the spray-dried base grains, the most important is of course the non-ionic surfactant. Although many nonionic surfactants with satisfactory physical properties can be used, including condensation products of ethylene oxide and propylene oxide with each other and with hydroxyl-containing bases, such as nonylphenol and alcohols of the oxo type, it is generally preferred that the nonionic surfactant is a condensation product of ethylene oxide and higher fatty alcohol. In such products, the higher fatty alcohol has from 10 to 20 carbon atoms, preferably from 12 to 16 carbon atoms, while the non-ionic surfactant contains from 3 to 20 ethylene oxide groups per moles, preferably from 6 to 12. Such surfactants are manufactured by the Shell Chemical Company and are available on the market under the trade names "Neodol" 23-6.5 and 23-7.

The enzyme preparations, which are normally added to the base grains after they have been prepared, can be any of a large variety of commercially available products, among them "Alcalase", manufactured by Novo Industri A/S, and "Maxatase", both of which are alkaline proteases ( subtilisin). Although the alkaline proteases are preferred, amylolytic enzymes, such as alpha-amylase, and likewise proteolytic enzymes can also be used. The mentioned detergents usually contain active enzymes in combination with a powdered carrier,

such as sodium or calcium sulfate, and the proportion of active enzyme can vary widely and is usually between 2 and 80% of the commercial product. The perfumes used, which are usually sensitive to heat and may contain some volatile solvent such as alcohol, are usually synthetic perfume materials, sometimes mixed with components of natural origin, and they will usually include alcohols, aldehydes, terpenes, fixatives and

other common perfume components. Flow-promoting agents, such as special clay materials, which are occasionally added to the detergent products, are unnecessary in the present case, although they are often useful in improving the flowability and reducing the stickiness of some detergents, possibly due in part to the presence of the bentonite and/or the polyacrylate. However, they can be added if desired, to further improve the flowability.

The quantity ratio between the different components

in the base grains will be such that the base grains become free-flowing and become sufficiently absorbent for a non-ionic surfactant that is supplied to the grains in a liquid state, so that the detergent produced from the base grains by incorporating such a surfactant will also be satisfactorily free-flowing. In addition, of course, the detergent produced from the base grains must be an effective cleaning agent, where the builders present assist the organic surfactant in aqueous solutions of the detergent, and it is important that the resulting product does not produce undesirable deposits of zeolite particles (possibly together with other substances, such as normally water-soluble silicates) on washed laundry.

It has been found that satisfactory base grains for this purpose may comprise, when silicate is present, from 15 to 30% by weight sodium carbonate, from 10 to 22% by weight sodium bicarbonate, from 20 to 40% by weight water softening aluminum silicate (zeolite), from 3 or 4 to 12 wt% sodium silicate and from

1 to 15% by weight bentonite, as the active components, and from

1 to 15% by weight of water. In such grains, the aluminum silicate will preferably be a sodium zeolite containing from 15

to 25% by weight of hydrated water. Preferably, such a zeolite will be Zeolite A. The preferred weight ratio between sodium carbonate and sodium bicarbonate in the product is approximately in the range from 1 to 3, and the grains preferably have a mass density in the range from 0.6 to 0.9 g/cm<3>, most preferably from 0.7 to 0.8 g/cm<3>, and the grain particle size is in the range of sieve No. 10 and sieve No. 100 (passes through No. 10 and is retained on No. 100)

(U.S. Sieve Series), most preferably in the area between sieve No. 10

and sieve No. 60. Further preferred proportions of the components are from 20 to 25% by weight sodium carbonate, from 13

to 19% sodium bicarbonate, from 30 to 37% hydrated zeolite, from 5 or 10% sodium silicate, from 5 to 8% bentonite and from 4 to 10% water, with the exception of the hydrate water of the zeolite. In such particularly preferred products, the weight ratio between sodium carbonate and sodium bicarbonate is in the range from 1 to 2.

When a polyacrylate is present together with the zeolite in the base grains, the proportion thereof will usually be in the range from 0.1 to 2%, preferably from 0.2 to 1.6% and most preferably from 0.8 to 1.4%. The quantity proportions of any additives, processing aids and fillers in the base grains will normally be limited to 20% of these, preferably from 1 to 10% and most preferably from 3 to 7%. The proportion of processing aids, when magnesium sulphate and citric acid are used, will normally be from 1 to 3% magnesium sulphate, preferably from 1.5 to 2.5%, and from 0.2 to 1% sodium citrate, preferably from 0.2 to 0.5 %. With respect to pigments and fluorescent brightening agents, the proportions will preferably be from 0.05 to 0.6% pigment, such as ultramarine blue, most preferably from 0.2 to 0.4%, and from 0.1 to 4% fluorescent brightening means, most preferably from 1 or 1.5 to 3%. These proportions of process aids and additives apply to the different types of grain according to the invention, when such process aids or auxiliaries are used.

The proportions of the different components in the mixer mixture and in the base grains when producing grains containing polyacrylate but not bentonite will be such that a uniform or nearly uniform mixture is obtained, and so that the grains are free-flowing and sufficiently absorb a non-ionic surfactant which is brought into contact with the grains in a liquid state so that the detergent produced from it by incorporating such a surfactant will also be satisfactorily free-flowing. It has been found that satisfactory base grains to achieve this comprise from 15 to 30% by weight sodium carbonate, from 10 to 22% by weight sodium bicarbonate, from 20 to 40% by weight water softening aluminum silicate (zeolite), from 3 or 4 to 18% by weight sodium silicate dg from 0.1 to 2% by weight of polyacrylate as active components, as well as from 1 to 12 or 15% by weight of water. The preferred weight ratio between sodium carbonate and sodium bicarbonate in the product is in the range from 1 to 3, the grains have a bulk density in the range from 0.5 to 0.8 g/cm<3>, preferably from 0.7 to 0.7 g/cm , and the grain particle size is in the range of sieve No. 10 to sieve No. 100 (passing through No. 10 and retained on No. 100) (U.S. Sieve Series), preferably from No. 10 to No. 60. Further preferred proportions of the components is from 20 to 25% by weight sodium carbonate, from 13 to 19% by weight sodium bicarbonate, from 30 to 37% by weight hydrated zeolite, from 7 to 15% by weight sodium silicate, from 0.5 to 1.5% by weight sodium polyacrylate and from 3 to 10 % water by weight, when the hydrate water of the zeolite is kept out. In particularly preferred products of this type, the weight ratio between sodium carbonate and sodium bicarbonate is in the range from 1 to 2.

When the grains to be produced will contain little or no water-soluble silicate, as was mentioned above in connection with other types of the new base grains, the proportions of the different components in the base grains will be such that the base grains will be free-flowing and will sufficiently absorb a non-ionic surfactant which is brought into contact with the grains in a liquid state, so that the detergent produced from the basic grains by incorporating such a surfactant will also be satisfactorily free-flowing.

It is also important that the product obtained does not result in an undesirable deposit of zeolite particles (possibly together with other substances) on washed clothes or objects. It is also desirable that the base grains have a suitable mass density and colour. It has been found that base grains which satisfactorily meet these objectives comprise from 15 to 30% by weight sodium carbonate, from 10 to 22% by weight sodium bicarbonate, from 10 to 50% by weight water softening aluminum silicate (zeolite), from 0 to 3% by weight sodium silicate and from 3 to 20% by weight of bentonite as active components, and from 1 to 15% by weight of water. The stated percentage of water is free water and does not include the zeolite's hydrate water. Similarly, the percentage of zeolite hydrate includes water. In certain cases, the product may be anhydrous with regard to the content of free water, but such cases are rare, and it is normally desirable to have at least a small proportion of water in the base grains to prevent an unwanted pulverization of these, as otherwise in some cases could occur for certain anhydrous compositions. The preferred weight ratio between sodium carbonate and sodium bicarbonate in the product is in the range from 1 to 3, the grains have a bulk density in the range from 0.6 to 0.9 g/cm 3, preferably from 0.6 or 0.7 to 0.8 g /cm 3 , and the grain particle size is in the range of sieve No. 10 to sieve No. 100 (passes through No. 10 and is retained on No. 100) (U.S. Sieve Series), preferably from No. 10 to No. 60. Even more preferred proportions of co-components are from 20 to 27% by weight sodium carbonate, from 14 to 51% by weight sodium bicarbonate, from 20 to 50% by weight hydrated zeolite, 0% by weight sodium silicate, from 5 to 20% by weight bentonite and from 1 to 5% by weight water , when the water of hydrate of the zeolite is disregarded. In these particularly preferred products, the weight ratio between sodium carbonate and sodium bicarbonate is in the range from 1 to 2. When silicate is present in such base grains, it will be preferred to limit the content thereof to 2%, preferably in the range from 0.5 to 1%. Other preferred ranges for the proportions of important components of the base grains according to the invention are from 35 to 45% hydrated zeolite and from 5 to 15%, preferably from 10 to 15%, bentonite.

When a polyacrylate is present in such base grains, the proportion thereof will normally be in the range from 0.05 to 0.5%, preferably from 0.05 to 0.3% and most preferably from 0.1 to 0.2%. Proportions of any additives, processing aids and fillers in such basic grains will normally be limited to 20% of these and are preferably from 1 to 10% and most preferably from 3 to 7%. The quantity ratios will be similar to those stated above.

Although it has been shown that detergents produced from the present basic grains do not require the presence of any corrosion-preventing additive to replace the silicate, it is within the scope of the invention to use suitable corrosion-preventing additives, and it would be preferable to use those which are stable under the prevailing conditions during the mixing operation and spray drying, and which has no adverse influence on these operations. Such corrosion-preventing additives or antioxidants can be organic or inorganic, as inorganic materials are normally preferred, and they will preferably be selected based on their ability to to prevent corrosion of aluminum parts in washing machines. If it is desired to continue to use a silicate for such a purpose or to use a silicate because of its action against hardness caused by magnesium ions, a powdered silicate will normally be preferred, for example anhydrous sodium silicate, which is marketed under the trade name "Britesil" and manufactured by Philadelphia Quarts Co.

(Na2O:SiO2 = 1:2.4). In that case, the silicate will be added after the base grains have been produced. However, other normally solid, soluble silicates, preferably of alkali metals, can also be added to the grains after the non-ionic surfactant has first been absorbed.

When it is desired that the product should have textile softening properties, softeners, preferably in dry powder form, can also be added to the base grains in an appropriate manner. This class of additives is well known, and most often such plasticizers are cationic compounds, especially quaternary ammonium compounds, such as quaternary ammonium halides. Particularly preferred are the higher alkyl, alkyl-aryl and arylalkyl-lower-alkyl quaternary ammonium chlorides and

-bromides, such as distearyldimethylammonium chloride. Among commercial softeners, the most preferred is that sold under the trade name "Arosurf TA-100", and manufactured

by Sherex Chemical Company, Inc. Such compounds also have antistatic and antibacterial properties, but if desired, other antibacterial additives can also be used, which are also preferably incorporated into the product by subsequent addition.

It is an important feature of the invention that an effective, builder-added detergent based on non-ionic surfactant alone can be produced by a commercially feasible process, but occasionally it may be desirable to also have an anionic surfactant or surfactant present in the final product , usually so that this will help to give the product foaming properties and additional cleaning ability. Normally, it will be preferred not to incorporate such anionic surfactant materials in the kneading machine, so that if such materials are to be used, it will preferably be by post-addition to the spray-dried base grains, and normally such post-addition will take place after the absorption of the non-ionic surfactant in a liquid state on the grains. Although many different types of anionic surfactants, preferably in powder form, possibly in a mixture with building materials, can be used, the preferred ones are linear higher alkylbenzene sulfonates, higher fatty alcohol sulfates and polyethoxylated higher fatty alcohol sulfates. In such products, the higher-alkyl parts and the higher-alcohol parts will normally contain 8-20, preferably 12-16 carbon atoms, and the surfactants will be present in the form of water-soluble alkali metal salts, preferably sodium salts. The epoxylated alcohol sulphate will normally contain from 3 to 20 mol of ethylene oxide per moles of fatty alcohol.

The ranges for the amounts of the different grain components in the finished detergent can easily be calculated from that given for the base grains, the amounts of surfactant and other materials added to the grains being subtracted. If the finished detergent has only added non-ionic surfactant, so that the finished product contains 20% non-ionic surfactant, the quantity range for the various components of the base grains can thus be calculated by multiplying by 0.8, i.e. by (100 - 20)/100. When the amount of non-ionic surfactant (in compositions where it is the only additive to the grains) is in the range from 8 to 25% of the detergent, the factors will similarly be from 0.75 to 0.92. Generally, the final percentage of nonionic surfactant in the product will be in the range from 8 to 25%, preferably from 15 to 22% and most preferably approx. 20%, but in certain situations and for certain types of products amounts in the range from 8 to 13% may be preferred. Normally the percentage of perfume in the final product will be in the range from 0.1 to 1%, preferably from 0.2 to 0.4%, while the percentage of enzyme will be from 0.5 to 3%, preferably from 1 or 1.5 to 2 .5%, and the percentage of flow improver, which may be subsequently added, will be less than 2%, preferably less than 1%. Of course, in order to calculate the areas for the grain components in the finished detergent, in addition to basing the calculations on the percentage of non-ionic surfactant in the finished product (post-added), you will also have to take into account the percentage of other post-added additives. If aqueous solutions of the additives are subsequently added, the addition will also affect the water content, which will often be kept in the range from 1 to 12%, but can occasionally be increased to 15%.

When polyacrylate is used and bentonite is looped,

are the quantity ranges for the various detergent components from 13 to 28% sodium carbonate, from 8 to 18% sodium bicarbonate, from 15 to 35% water softening aluminum silicate, from 3 to 40% sodium silicate, from 0.1 to 1.6% polyacrylate, from 8 to 30 % nonionic surfactant and from 1 to 10% water. Preferably the ranges are from 16 to 21% sodium carbonate,

from 10 to 15% sodium bicarbonate, from 22 to 32% hydrated zeolite, from 8 to 13% sodium silicate, from 0.5 to 1.5% sodium polyacrylate, from 3 to 6% (and occasionally from 3 to 10%) moisture and from 10 to 22 or 25% nonionic surfactant. The percentages of processing aids, clarifying agent and dye in the finished detergent will be approximately the same as in the base grains and are preferably in the range from 0.2 to 0.6% for sodium silicate (obtained by adding citric acid) and from 1 to 2% for magnesium sulfate, from 0.1 to 0.3% ultramarine blue and from 1.5 to 2% for the fluorescent brightening agent. The enzyme content will be in the range from 0.5 to 3%, being usually from 1 to 2%, and the perfume content will be from 0.1 to 1%, preferably from 0.2 to 0.4%.

The quantity ranges for the different grain components

in the spray-dried part of the finished detergent how little

or no silicate is present, can be calculated in the manner described above. As regards the post-added components, the percentage of non-ionic surfactant will be the same as above, while the percentage of perfume in the final product will be in the range from 0.1 to 1%, preferably from 0.2 to 0.4%, and the percentage of enzyme will be from 0.5 to 3%, preferably from 1 to 2%. If an aqueous silicate is subsequently added, the amount of this will usually be from 2 to 10%, preferably from 3 to 8%, for example approx. 5%. When a softening compound is present in the final product, the amount thereof will normally be in the range from 3 to 12%, preferably from 5 to 10%, and when one or more anionic surfactants are used, the percentage thereof will be limited to no more than the amount of non-ionic surfactant, and the total amount of anionic and non-ionic surfactant in the final product will be within the ranges given above for non-ionic surfactant alone. If anionic surfactant is used, the amount of this will usually be in the range from 0.2 to 0.8 times the weight of the non-ionic surfactant. In order to calculate the quantity ranges for the grain components in the finished detergent, one must, of course, in addition to basing weight calculations on the percentage of non-ionic surfactants in the final product

(post-added) also take into account the percentages of other post-added additives. If the aforementioned additions are made using aqueous solutions of the additives, the moisture content will also be affected, but this will usually be kept in the range from 1 to 12% in the final product, although it can occasionally be increased to 15%.

The base grains are spray-dried from an aqueous kneader mixture which will normally contain from 40 to 70 or 75% solids, preferably from 50 to

60% solids, the rest being water, preferably deionised water as described above, although ordinary tap water can also be used. The ranges for the addition of the kneading machine mixture can be calculated from the ranges for the desired base grain composition on the basis of the moisture content in the grains and in the mixture. In a kneader mixture which is to contain 50% water, and from which base grains containing 5% water are to be produced (disregarding the hydrate water of the zeolite), the percentages of the components in the base grains must be multiplied by 10/19, namely (100/2[100 - 5]). The above calculations are sufficient for components that do not decompose during the spray drying operation, but it is known that part of the bicarbonate is transferred to carbonate when it is dried at elevated temperatures in a spray drying tower. When you know the characteristics of the tower and the drying conditions, so that the degree of decomposition of the bicarbonate is predictable, you can consequently calculate the quantity ratio between carbonate and bicarbonate in the kneading machine mixture. If, for example, it is desired to produce a product that contains approx. 2 2% sodium carbonate and approx. 16% sodium bicarbonate, one would, in cases where approx. one third of the bicarbonate is split into carbonate in the spray drying tower (since two parts carbonate is obtained from three parts split bicarbonate), could add 24% bicarbonate and 17% carbonate to the kneader (on a dry weight basis).

With regard to the different compositions and calculations, it is considered that the zeolite in the kneading machine mixture and in the spray-dried base grains and the detergent is hydrated to approx. 20% hydrated water, but the degree of hydration may vary. However, such a constant degree of hydration will be assumed in order to have a basis for comparison and for the purposes of the calculations.

Kneading machine bla.' the thing from which the base grains according to the invention are preferably produced by spray drying,

is one which is mainly inorganic, and the content of organic matter is usually limited upwards to 10%, preferably to 7% and most preferably to 4%, on a dry weight basis. Among such organic materials which may be present, mention may be made of citric acid materials (citric acid and soluble citrates), fluorescent brightening agents, polyacrylate, dyes and pigments. Also other organics

in materials may be present, including hydrotropic salts, chelating agents and polyelectrolytes, but the kneading machine mixture will consist primarily of inorganic materials and water.

As regards the polyacrylate-containing grains, which do not contain bentonite, the kneading machine mixture on a solids basis will normally consist of from 10 to 25% sodium carbonate, from 15 to 30% sodium bicarbonate, the weight ratio between sodium bicarbonate and sodium carbonate being in the range from 0.5 to 2, from 20 to 40% water softening aluminum silicate, from 4 to 18% sodium silicate and from 0.1 to 2% polyacrylate. When processing aids are present, the percentage thereof, calculated on the same basis, will usually be from 1 to 3% magnesium sulfate and from 0.2 to 1% sodium citrate. Preferably, in such kneading machine mixtures, the content of sodium polyacrylate will be from 0.5 to 1.5%, and when processing aids and dyes are also present, the percentages of these will be from 1.5 to 2.5% magnesium sulfate, from 0.2 to 0 .5% sodium citrate, from 0.2 to 0.4% ultramarine blue and from 1.5 to 3% fluorescent brightening agent, all calculated on a solids basis.

The kneading machine mixture is preferably prepared by adding the various components one after the other in the manner that will give the most mixable, easiest pumpable and non-sedimenting slurry for spray drying. The order of addition of the various components may vary, depending on the circumstances, but it is highly desirable to add the silicate solution (if one is used) last or at least after the addition of any material combinations preventing gel formation or sedimentation or process aids . Normally, it is preferred that all or almost all of the water is added to the kneading machine first, preferably at approximately the desired mixing temperature, after which any processing aids and other minor components, including pigments and fluorescent brightening agents and any polyacrylates are added, followed by the bentonite (if such is used) , the zeolite, the bicarbonate, the carbonate and the silicate (if such is used). During such additions, each individual component will usually be thoroughly mixed before the next component is added, but the methods of addition can be varied, depending on the circumstances, and simultaneous additions can be made when this is appropriate. Occasionally, component additions, such as silicate additions, can be made in two or more stages. Different components can be pre-mixed before the addition is made, to speed up the mixing process. Generally, the mixing speed and mixing energy will be increased as the materials are added. For example, low speeds can be used until the last of the bentonite component and the zeplite component have been mixed, after which the speed can be increased to medium speed and then to high speed before, during or after the addition of any silicate solution.

The temperature of the aqueous medium in the kneading machine will usually be around room temperature or higher and is normally in the range from 20 to 80° C, preferably in the range from 30 to 75° C and most preferably in the range from 40

to 70° C. Heating the kneader medium can accelerate the dissolution of the water-soluble salts of the mixture and thereby increase miscibility, but the heating, when carried out in the mixer, can slow the production rate and cause the mixture to solidify. An advantage of having process gelling agents present in the mixture is therefore that it ensures the formation of the desirable non-gel-forming slurries at both lower and higher temperatures. Temperatures above 80°C (and sometimes 70°C) will usually be avoided due to the possibility of decomposition of one or more of the constituents of the mixer mixture, e.g. the sodium bicarbonate. Likewise, in some cases, lower mixing machine temperatures will increase the upper limits for the solids content in the mixing machine, probably because they make normally gel-forming or hardening-promoting components insoluble.

The mixing times necessary to obtain good slurries can vary widely, from as little as 5 minutes in small mixers and for slurries with a high water content, to as much as 4 hours,

in certain cases. The mixing times necessary to bring all of the mixing machine components into substantially homogeneous mixing with each other in one medium can be as short as

such as 10 minutes but in some cases up to 1 hour, although 30 minutes is a preferred upper limit. Including such initial mixing times, normal mixer periods will be from 15 minutes to 2 hours, for example from 20 minutes to 1 hour, but the mixer mixture must be such that it is mobile and does not form a gel or solidify for at least 1 hour, preferably 2 hours and most .preferably for 4 hours or longer after the final preparation of the mixture, and the mixture may even be mobile for as long as from 10 to 30 hours before the pumping out to the spray drying tower takes place, with a view to situations where other difficulties in production arise.

The slurry produced in the mixer, with

the various salts and other constituents dissolved or in particulate form and uniformly distributed are then transferred in the usual manner to a spray drying tower, which is normally located near the mixing machine. The slurry is drawn from the bottom of the mixer to a positive displacement pump, which forces the slurry at high pressure through spray nozzles at the top of a conventional spray drying tower (counter-flow or co-flow), in which the droplets of the slurry fall through a hot drying gas, usually the combustion products of the pre- burning of fuel oil or natural gas, in which the droplets are dried to the desired grain shape. During drying, part of the bicarbonate (often from 1/4 to 1/2, e.g. 1/3) can be transferred to carbonate with the release of carbon dioxide, which, together with the polyacrylate that may be present in the spray-dried mixture, improves the physical properties of the produced grains, so that they become more absorbent for liquids, such as liquid non-ionic surfactants, which can later be sprayed onto the grains. However, the zeolite and bentonite components of the manufactured base grains also appear to promote liquid absorption, and the polyacrylate also improves the drying rate, increasing throughput through the tower.

After drying, the product is sieved to the desired size, for example to size 10 to 60 or 100 according to the U.S. Sieve Series, and it is then ready for spraying a non-ionic surfactant, which spraying is carried out with the grains in either a warm or (to room temperature) cooled state. However, the nonionic surfactant will normally be present at an elevated temperature, such as at a temperature of from 30 to

60° C, e.g. 50° C, to ensure that it will be liquid. On cooling to room temperature, however, it will preferably be a solid, often wax-like substance. Although the nonionic surfactant is somewhat sticky at room temperature, it will not

this property gives the finished material poor flow properties, because the surfactant penetrates into and below the grain surface. The non-ionic surfactant, which is applied to grains in motion or tumbled grains in a known manner, in the form of a spray or as small drops, is preferably a condensation product of ethylene oxide and a higher fatty alcohol, as described above, but also other non- ionic surfactants can be used. The enzyme preparation (referred to here as enzyme, although it will be understood that it also includes a carrier material), hydrate-aqueous silicate and any other powdered auxiliaries to be subsequently added, can be applied to the detergent particles in the form of a dust, and perfume and other liquids can be sprayed on at a convenient time, before or after the addition(s) of the powder or powders.

The spray-dried basic grains and detergent -

lene produced from these may contain little or nothing

silicate from the mixer mixture, and in such cases silicate in solid form can be added afterwards. The optionally added powdered silicate does not seem to react with the zeolite to the same extent, so that the amount of zeolite-silicate agglomerates, which tend to be deposited on washed clothes and objects, is reduced. Although without bentonite present one would normally use silicate, at least because of its corrosion-preventing effect, it has been shown that the available detergents do not corrode aluminium, even without the silicate. Moreover, the bentonite has no detrimental effect on the stability of the product and actually appears to help hold the grains together and make them resistant to crushing and pulverization during transport and use. The presence of bentonite and/or polyacrylate significantly improves the properties of the finished product

detergent, as the bentonite gives greater binding rates for calcium ions and gives less deposition of zeolite on washed clothes. When the low molecular weight polyacrylate is present, the grains become more porous and better absorb the non-ionic surfactant in liquid state, without the product's bulk density being reduced to an undesirable degree. Considering that bentonite is a clay and would be expected to cause difficulties with deposition and gelation, the reduced deposition of zeolite and the absence of gelation is surprising and an important result of the invention.

The following examples illustrate the invention. Unless otherwise stated, all temperatures are calculated

in °C and parts by weight. This applies to both the examples and the rest of the description. When amounts and proportions of zeolite are stated, these are calculated on the basis of the normal hydrate, because it is assumed that the hydrate water of the zeolite does not leave the zeolite and becomes part of the aqueous solvent medium in the operations carried out in the mixing machine, and likewise because some of the water which is present in the base grains and in the detergents, is present as the zeolite's water of hydrate.

Example 1

A 4536 kg batch of a mixer mix

for spray drying to basic grain and transfer to a detergent according to the invention is prepared by adding to the mixing machine 1832 kg of deionized water at a temperature of approx. 27° C, with subsequent mixing at low speed in the mixing machine, with the addition of 51.3 kg of anhydrous magnesium sulphate (105.5 kg of Epsom salts can be used instead, in which case the originally added amount of water will be reduced to 1777.4 kg ), 12.7 kg citric acid, 57.6 kg "Tinopal 5BM" Extra Conc. (CIBA-Geigy), 68 kg ultramarine blue powder, 169.6 kg "Thixo-Jel" No. 1 (bentonite), 914 kg (Linde hydrated "Zeolite 4A", 20% water of crystallization), 636.9 kg sodium bicarbonate and 456 .3 kg of sodium carbonate (soda ash). The mixing speed is then increased to high speed (in certain cases it can be increased to medium speed at an earlier stage, if the mixture does not mix as well as desired),

and 189.6 kg of sodium silicate with a quantity ratio of Na 2 O : SiO 2

of 1:2.4 is mixed in (as 399.2 kg of 47.5% aqueous solution). The mixing of the entire portion is continued for approx. 1 hour (in some cases a mixing time as long as 4 hours can be used) during which from 90.7 to 272.2 kg of water can be lost through evaporation, which amount of water can be replaced by refilling, if desired. While mixing is in progress, the slurry in the mixer is continuously moving and does not gel, solidify or cake. Because bicarbonate is partially split into carbonate during spray drying, the amount of this can vary, depending on the operating conditions in the spray drying tower.

As you start approx. 5 minutes after all of the ingredients in the mixer mixture have been added, the mixture is allowed to fall from the mixer into a pump, which with a pressure of approx. 21 kg/cm 2 pumps the mixture to the top of a spray drying tower for countercurrent operation, where the initial temperature is approx. 430° C and the final temperature is approx. 105° C. The mainly inorganic base grains obtained have a mass density of from 0.6 to 0.7 g/ml, an initial adhesion of approx. 40% and a particle size in the range mainly between 10 and 100 mesh (U.S. Sieve Series)

(they are aimed at this area), as they have a content of fine particles (passing through U.S. Sieve No. 50) of approx. 15%. The moisture content of the grains is approx. 7%. The base grains are found to be free-flowing, non-sticky and of satisfactory porosity, while having a solid surface, and are capable of readily absorbing significant amounts of liquid non-ionic surfactant without becoming undesirably tacky.

Detergent products are produced from the spray-dried grains by spraying onto the surface of the tumbled grains a normal waxy non-ionic surfactant, either "Neodol"

23 - 6.5 or "Neodol" 23-7, in a heated liquid state, in such an amount that a final product containing 20% non-ionic surfactant is obtained, and a proteolytic enzyme (Alcalase) is applied in powder form in an amount that gives a concentration of 1.99% in the product. Perfume is sprayed onto the product until a concentration of 0.25%. The detergent products obtained have a mass density of approx. 0.7 or 0.8 g/ml and contains 27.3% zeolite (hydrated), 20.1% of the non-ionic surfactant, 17.8% sodium carbonate (some of which has been formed by cleavage of sodium bicarbonate), 12.7% sodium bicarbonate, 5.6% sodium silicate, 5.45% water, 2.0% enzyme, 1.7% fluorescent brightener, 1.5% magnesium sulfate, 0.4% citric acid (as citrate), 0, 25% perfume, 0.2% ultramarine blue and 5.0% bentonite ("Thixo-Jel"). The manufactured detergent of the above formula is an excellent, powerful laundry detergent and is particularly useful as a household laundry detergent for use in automatic washing machines. It is physically and aesthetically advantageous and attractive, because it does not dust and, moreover, it is a lot

free-flowing, which makes it possible to package it in glass and plastic bottles with narrow necks, from which it can be easily poured. The detergents according to the invention which contain bentonite have been shown to have significantly improved binding capacity for calcium ions, but even more importantly, they leave smaller amounts of residue on the washed laundry (in an automatic washing machine at the usual concentrations for such a product and at normal washing temperatures) than similar detergents that do not contain bentonite. This difference is amplified when the washing water has a high hardness, for example a hardness of 200 ppm, calculated as calcium carbonate, when the washing water is cold and when a mild agitation cycle is used.

In a control trial, base grain was produced where the bentonite was omitted from the mixing machine mixture, being replaced with equal weight amounts of sodium carbonate and sodium bicarbonate, the total amount of added materials corresponding to the weight amount of the replaced bentonite. The mixer mixture was spray-dried and transferred to a detergent in the same way as in the preparation of the detergent according to the invention. This "control product", although usable as a detergent, produced a greater deposit of residual materials on the washed laundry than the above-produced detergent product according to the invention and bound a smaller amount of calcium. When, in a similar way, the content of silicate in the control grains is increased to 10.7%, with a corresponding reduction in the concentrations of sodium carbonate and sodium bicarbonate to compensate for the increase in the silicate concentration, the deposition of the residual material is even greater than with the control detergent.

When following the normal procedure, mixer mixes will form quickly, and they will be able to be discharged from the mixer just as quickly. Thus, they will occasionally be able to be formed in as little as 5 minutes and pumped out of the mixer in as little as 10 minutes. Nevertheless, it is often important that the present mixtures are able to stand for at least 1 hour in the mixing machine without gelling or solidifying, because such delays in production occasionally occur in commercial operations. The described mixer mixture is capable of being held in the mixer for as long as 4 hours and often significantly longer, without gelling or solidifying, which is attributed, at least in part, to the content of magnesium sulfate and citric acid as process gelling agents. However, other processing aids can be used instead with a view to avoiding gelation and solidification of the mixer mixture, and under certain conditions the quantities of these can be reduced and one or both omitted. Similarly, other minor constituents of the mixer mixture, such as the fluorescent clarifier and pigments, may be omitted from the mixture, and enzymes and perfume may be omitted from the final product, although it is strongly preferred that such materials be present. The temperature of the mixer mixture can be changed, for example increased to 52°C, and the amounts of the different ingredients can be varied by +10%, +20% and +30%, while still keeping them within the above ranges, whereby still usable mixing machine mixtures will be obtained which provide the desired basic grains and detergents.

Instead of anhydrous magnesium sulfate, an equivalent amount of Epsom salts can be used, and various other ingredients can be added as aqueous solutions, provided that the amount of water added together with these is subtracted from the amount added to the mixing machine. Other addition orders can be used, but normally it will be desirable to add the processing aids early during the manufacturing process, while the silicate is added last or towards the end. Instead of "Zeolite 4A" "Zeolite X" and "Zeolite Y" can be used and likewise other types of "Zeolite A". Although it is preferred to use the hydrated 'Eeolite 4A' of this example, various degrees of hydration of the zeolite are acceptable, and in certain cases near anhydrous crystalline zeolites or amorphous zeolites may be used. By varying the amount of bentonite within the range indicated, for example at 3% and 10%, still give usable products, but those products containing higher amounts of bentonite will generally be more effective in preventing zeolite from being deposited on laundry. However, the amount used commercially will depend on a number of factors, and it will usually represent a balance between the desired reduction of zeolite deposition and the desired building effect and other functional effects of other detergent ingredients.

Example 2

A product similar to the product according to Example 1 is produced, but with the addition of low-milk polyacrylate (molecular weight 1000 - 2000) in the mixing machine mixture, the addition being made early during the production of this, before the addition of the bentonite, so that a comparable product is obtained containing 1% of the polyacrylate ("Alcosperse 107D"). The only change made to the formula to compensate for the addition of the polyacrylate is an equal reduction in the amount by weight of sodium bicarbonate in the mixer mixture. In addition, a smaller portion is produced, using a mixing machine on a semi-technical scale. The base grains obtained by spray drying, which is carried out in the same way as previously described in Example 1, are transferred to a finished detergent product of the same type as that according to Example 1, with the exception of the addition of the polyacrylate. The detergent is tested and its properties determined. It is found to be an excellent free-flowing detergent, which produces less zeolite deposits on laundry than control detergents of the types mentioned in Example 1. Moreover, the presence of the "Alcosperse" material significantly improves the absorption properties of the manufactured grains, so that these more easily absorbs liquid non-ionic surfactant,

which can be of the epoxylated alcohol type or of other types mentioned in this description. Nevertheless, the mass density of the grains and the detergent product is not reduced to a significant extent, which is essential when it is desired to produce a concentrated, particulate detergent with a relatively high mass density. It has been found that when the described polyacrylate is present in the mixer mixture, an improvement in spray drying operations is achieved and less material is lost by deposition on the walls of the spray drying tower.

Such operational advantages are important in terms of increasing production speed and in terms of avoiding waste of materials and reworking of material that does not meet specifications.

In the same way as in Example 1, the quantities of the components in this example can also be varied, within the limits given in this description, to form basic grains and detergents with improved properties. Although it seems that approx. 1% of the described polyacrylate is an optimal amount in the detergents, amounts of from 0.1 to 2% of the polyacrylate will give a good effect, as the use of the larger amounts results in greater improvement of the porosity of the grains. Instead of 1%, 0.5% and 1.5% are also desirable amounts of the polyacrylate. In certain cases, it may be desirable to use polyacrylates with a higher molecular weight within the given ranges, e.g. with molecular weight within the range 4000 - 5000, but in most cases the lower part of the range will be preferred. In the same way as in Example 1, in some cases process aids, perfume, enzyme, fluorescent brightening agent and pigments can be omitted or replaced, but in all such cases the zeolite, carbonate, bicarbonate, silicate and bentonite and likewise the polyacrylate will be present in the given amounts in the base grains, and non-ionic surfactant will also be present in the finished detergent, which, like the others, is of the phosphate-free type.

Example 3

Using equipment on a semi-technical scale, detergent base grains are produced containing 23.37% sodium carbonate, 16.60% sodium bicarbonate, 34.74% Zeolite 4A, 13.64% sodium silicate (with a ratio of Na20:SiO2

of 1:2.4), 0.26% Ultramarine Blue, 2.20% "Tinopal 5BM" Extra Conc. (CIBA Geigy), 1.95% magnesium sulfate, 0.32% citric acid (present in the form of sodium citrate), 1.29% sodium polyacrylate with a molecular weight in the range of 1000 to 2000 ("Alcosperse 107D") and 5.64% moisture. Such a product is produced by spray drying a portion from a mixing machine on a semi-technical scale, containing 50% solids and 50% water, including water added to the aqueous silica solution and added with the polyacrylate (such as when an aqueous solution thereof, for example in the form of "Alcosperse 10 7" is used) and with epsom salts, if such are used.

The other solid components make up the other 50% of the mixer mixture, and they are present in the same relative quantities as those stated there for the base grains, with the exception of the sodium carbonate and sodium bicarbonate, of which, on the condition that 1/3 of the bicarbonate is split to carbonate, 24.90 parts sodium bicarbonate and 17.84 parts sodium carbonate are used.

The water supplied to the mixer is deionized water and maintains a temperature of 27° G. The magnesium sulfate that is added is anhydrous, although an equivalent amount of Epsom salts can be used instead. After the water has been added, the magnesium sulfate, citric acid, "Tinopal 5BM" Extra Conc, ultramarine blue powder and "Alcosperse 107D" are added to the mixer, normally with the mixer running at a relatively low speed, after which the hydrated zeolite 4A (Linde) (20% water of crystallization) , the sodium bicarbonate and the sodium carbonate can be added while the mixer is running on low or medium speed. The mixing speed is then increased to high speed, and the sodium silicate is added in the form of a 4-7.5% aqueous solution. The mixing of the complete portion is then continued for approx. 1 hour (in certain cases a mixing time as long as 4 hours may be used), during which a considerable amount of water, sometimes from 2 to 6%, may be lost by evaporation. If desired, this water can be replaced by topping up with new water. During mixing, the mixer slurry is constantly moving, and it neither gels, solidifies nor clumps together. Because the splitting of bicarbonate can vary with the spray drying conditions, the amount of bicarbonate and carbonate supplied can also be varied accordingly to achieve the desired composition of the base grains.

As you start approx. 5 minutes after all of the ingredients of the mixer mixture have been added, the mixture is allowed to fall from the mixer into a pump which pumps the mixture at a pressure maintained at approx. 21 kg/ cm o, to the top of a spray drying tower which is operated under counter-flow conditions, and where the starting temperature is approx. 430° and the final temperature approx. 10 5° C. The mainly inorganic base grains obtained have a bulk density of from 0.6 to 0.7 g/ml, low tackiness, a particle size range mainly between 10 and 100 mesh according to the U.S. Sieve Series (they are aimed at this size range) and contain no unacceptable amount of fine particles. The grain's moisture content is approx. 5.6%. The base grains are found to be free-flowing, non-sticky, satisfactorily porous and yet have the desired physical strength, and are readily capable of absorbing increased amounts, e.g. from 2 to 5% more, of liquid nonionic surfactant that is sprayed onto the grains, without becoming unacceptably sticky.

In addition to the desirable properties of the manufactured base grains, it is worth noting that the buildup of product on the inner walls of the spray drying tower is less, often from 20 to 50% less, than when the polyacrylate is not present in the mixture. The flow through the tower increases, and it seems as if the content of fine particles in the product decreases. The reduction in the build-up and the formation of fine products leads to significantly less recycling.

Detergent products are produced from the spray-dried grains by spraying onto the surface of the tumbled grains a normal waxy non-ionic surfactant, either "Neodol" 23-6.4 or "Neodol" 23-7, in a heated liquid state, in such an amount that a final product containing 20.7% non-ionic surfactant is obtained, and a proteolytic enzyme (Alcalase) is applied in powder form to a concentration of

1.32%. Perfume is sprayed onto the product up to a concentration of 0.25%. The detergent products obtained have a mass density of approx. 0.7 g/ml and contains 27.0% zeolite (hydrate), 20.7% of the non-ionic surfactant, 18.17% sodium carbonate (some of which is formed by cleavage of sodium bicarbonate), 12.9% sodium bicarbonate , 10.6% sodium silicate, 4.39% moisture, 1.32% enzyme, 1.71% fluorescent clarity control agent 1.51% magnesium sulfate, 0.25% citric acid (in citrate form), 0.25% perfume , 0.2% ultramarine blue and

1.0% sodium polyacrylate. The detergent thus produced is an excellent, powerful laundry detergent and is particularly useful as a household laundry detergent for use in automatic washing machines. It is advantageous and attractive in physical and aesthetic terms, because it does not dust and is also extremely free-flowing, which enables the packaging of the detergent in glass or plastic bottles with a narrow neck,

from which bottles the detergent can easily be poured out and portioned out. Comparison tests carried out with a view to comparing the detergents according to the invention with corresponding detergents that do not contain the polyacrylate, have shown that the detergents according to the invention have an improved ability to remove dirt and stains, when tested with different dirt materials and stains on a large selection of test substances, including cotton, polyester-cotton blends, polyesters and other synthetic substances. As far as stain removal is concerned,

it has often been found that the polyacrylates are often more effective against stains than larger amounts of more expensive enzymes, which are usually more specific with regard to stain removal action and are therefore not as effective against the combinations of stains that occur in many loads of laundry. Detergents according to the invention which contain poly-

the acyrylate, likewise exhibits excellent action against redeposition, as they help to prevent the washed laundry from being soiled again by the redeposition of removed dirt.

The manufacturing process may be similar to those described in Example 1, and various process aids and additives may be added, as indicated in Example 1. Likewise, certain additives may be omitted as mentioned in Example 1. The temperature of the mixer mixture may be modified, for example increased to 52° C, and the amounts of the different components can be varied by +10%, +20% and +30%, while still keeping them within the previously indicated ranges. There will then still be usable mixing machine mixtures that provide the desired basic grains and detergents. Several compounds can be added as aqueous solutions, provided that the amount of water added with the compound is subtracted from the amount of water added to the mixer according to the formula. Other addition sequences can also be used. Instead of "Zéolite 4A", "Zeolites X" and "Zeolites Y" can be used, as well as other types of "Zeolite A". although it is preferred to use the hydrated "Zeolite 4A" according to this example, various degrees of hydration of the zeolite will be acceptable, and in certain cases near anhydrous crystalline zeolites or amorphous zeolites may be used. Varying the amount of polyacrylate within the given range in the base grains, for example to 1.0% and 1.7%, still results in usable products, but those containing higher amounts of the sodium polyacrylate will usually be more effective in cleaning effect, absorption of non-ionic surfactant and promotion of improved operating conditions in the tower. It would usually not be desirable to use more than approx. 2% of the polyacrylate, because its effectiveness decreases at higher concentrations, and because the gains that can be made,

cannot be defended financially.

Example 4

A product similar to the product according to Example 3 is produced, however "Alcosperse 10 7" is used, which is a solution of sodium polyacrylate where the polyacrylate has a molecular weight of 1000 or 1000 - 2000. The solution is a clear, amber colored liquid with 30% solids content. The amount of "Alcosperse 107" that is used is, with regard to solids content, equivalent to the amount of "Alcosperse 107D" used in Example 1. Instead of "Alcosperse 107", suitable amounts on a solids basis of "Alcosperse 104" (25% solids content) and "Alcosperse 149") (40% solids content) can be used, but the result obtained with the type 10 7 is better, and therefore "Alcosperse 107". No other significant changes are made to the formula, compared to Example 3, nor to the manufacturing process.

The base grains obtained by spray-drying the prepared mixing machine mixture are transferred by means of the described method to a finished product using "Neodol" 23-6.5 as the non-ionic surfactant. The product made using "Alcosperse 107" is used as an excellent phosphate-free detergent, which is useful as a heavy-duty, built-up laundry detergent, and which is effective against a wide variety of stains, including stains from liquid cosmetic make-up and synthetic sebum ( Spangler type). An experimental group of ten people clearly prefers such a product to a comparable product in which "Alcosperse 107" is omitted. This preference is also supported by instrumental measurements carried out on the washed clothes or materials. The mentioned tests are carried out on textiles made of cotton, "Dacron" cotton and nylon, and the test conditions include machine washing in water with a hardness of 150 ppm with a detergent concentration of 0.07% by weight and a water temperature of 49°C.

The same advantages in the manufacturing process as mentioned in Example 3 can be observed, including an excellent dispersion of the materials in the mixing machine and a spray drying of the product without excessive deposits. The base grains have measurably greater porosity than the control grains (which do not contain polyacrylate). However, the mass density is not reduced by more than a few percent, e.g. 3%, which is important for such concentrated products. Corresponding results are obtained by varying the content of the other essential components by +15% and +_30%, the amount being kept within the specified ranges. Such results are obtained when using other types of "Zeolite A" with a different degree of hydration, e.g. 15 or 22% hydration, and when using polyacrylates with a molecular weight in the range from 1000

to 5000. Preferably, such polyacrylates are neutralized with sodium, either completely or to at least approx. 50%, but also polyacrylates that have been neutralized to a lesser extent can be used.

Results similar to those stated here can also be obtained when the clarifying agent, perfume, enzyme and processing aids (citric acid and magnesium sulfate) are omitted, but in such cases it must be ensured that the spray drying is carried out quickly after the preparation of the mixer mixture, so that the mixture does not solidify in the mixer. Likewise, of course, the individual contributions from the omitted materials will be lost, but the product will still be a good laundry detergent, as discussed above, and the mixer mixture will be well dispersed and will be easily dried, and the base grains will have improved porosity.

Example 5

A 4536 kg batch of mixer mixture for formation by spray drying of base grains according to the invention which does not contain any soluble silicate, is prepared by adding to a mixer 2132 kg of deionized water with a temperature of approx. 2 7° C and then, in sequence, and first at low1 mixing speed, addition to the mixer of 4 7.2

kg "Tinopal 5BM" Extra Conc. (CIBA-Geigy), 5.9 kg powder, ultramarine blue, 3.2 kg sodium polyacrylate ("Alcosperse 107D"), 957.5 kg Linde hydrated zeolite 4A (with 20% water of crystallization), 283.5 kg "Thixo-Jel" No. 1 (bentonite), 714.4 kg sodium bicarbonate (technical grade), 351.1 kg sodium carbonate (natural soda ash) and 41.3 kg titanium dioxide

(Anatase). During the mixing of the various components, the mixing speed is increased to a medium mixing speed and finally to a high mixing speed, and after the addition of all components, which was approx. 15 minutes, the mixture is continued for approx. 1 hour (in some cases for as long as 4 hours), during which some of the water present, for example from 90.7 to 272.2 kg, may be lost by evaporation and possibly replaced. While mixing is in progress, the mixer slurry is constantly moving,

and it does not undergo gelation, solidification or caking. Because bicarbonate is partially split into carbonate during spray drying, the amounts of bicarbonate and carbonate added to the mixer can be varied, depending on the operating conditions in the spray drying tower.

About. 5 minutes after all ingredients have been added to the mixer mixture, the mixture is allowed to sink from the mixer to a pump, which pumps the mixture at a pressure of approx. 21 kg/cm 2 to the top of a spray drying tower which is operated under counterflow conditions, and where the starting temperature is approx. 430° C and the final temperature approx. 105° C. The predominantly inorganic base grains obtained have a bulk density of from 0.6 to 0.7 g/ml, an initial adhesion of less than 10%, a particle size range of predominantly between 10 and 60 mesh according to the U.S. Sieve Series (they are intended for this area), and a content of fine particles of approx. 15% (passing through U.S. Sieve No. 50). The grain's moisture content is in the range from 1 to 10%. The base grains are found to be free-flowing (80% flow rate), non-sticky, satisfactorily porous while having a solid surface, and are capable of readily absorbing significant amounts of liquid non-ionic surfactant without becoming undesirably tacky.

Detergent products are produced from the spray-dried grains by spraying a normal waxy non-ionic surfactant onto the surface of tumbled grains. "Neodol 23-6.5" is used, but "Neodol 23-7" or "Neodol 25-7" can be used instead. The non-ionic surfactant exists in a heated liquid state (at a temperature of approx. 45° C). The quantity sprayed on is such that a final product containing approx. 20% non-ionic surfactant. A proteolytic enzyme (Alcalase) is applied in powder form until a concentration of 1.5% has been achieved in the product, and perfume is sprayed onto the product up to a concentration of 0.25%.

The detergents obtained have a mass density of from 0.7 to 0.8 g/ml and contain 32.45% zeolite (hydrated), 19.7% of the non-ionic surfactant, 18.5% sodium carbonate (some of which was formed by cleavage of sodium bicarbonate), 13.5% sodium bicarbonate, 1.3% free water, 1.4% enzyme, 1.6% fluorescent brightener, 0.25% perfume, 0.2% ultramarine blue, 9.6 % bentonite ("Thixo-Jel"), 0.1% sodium polyacrylate and 1.4% titanium dioxide. The prepared detergent of the above formula is an excellent heavy-duty laundry detergent, which is useful as a household detergent for use in automatic washing machines.

It does not dust and is very free-flowing. Detergents similar to what is described in this example, and which contain bentonite as mentioned, are found to have a significantly improved ability to bind calcium ions, but even more importantly, they leave less residual amounts of zeolite on clothes that have been washed in an automatic washing machine, especially when such washed laundry is dried on a line, than similar detergents that contain less bentonite, and that contain sodium silicate in the spray-dried base grains. This difference is amplified when the washing water has a high hardness content, e.g. 200 ppm, calculated as calcium carbonate, when the wash water is cold, and when a mild agitation cycle is used.

Manufacturing processes can be used, with variations, such as the one described in Example 1, and certain additives can be omitted, as mentioned in Example 1. The amounts of the different components can be varied by +10%,

+20% and +30%, while keeping them within the above stated quantity ranges, whereby usable mixer mixtures will still be obtained which provide the desired grains and detergents. The solids content in the mixing machine mixture can be varied within the quantity range indicated above, e.g. to 45% and 65%, whereby good is still obtained

mixing and good spray drying. Instead of "Zeolite 4A" "Zeolite X" and "Zeolite Y" and likewise other types of "Zeolite A" can be used. Although it is preferred to use the hydrated "Zeolite 4A" according to this example, various degrees of hydration of the zeolite are acceptable, and in some cases near anhydrous crystalline zeolites or amorphous zeolites may be used. Varying the amount of bentonite within the given range, to 10% and 17% for example, still gives usable products, but those containing the larger amounts of bentonite will usually be more effective in helping to prevent zeolite deposition on the washed laundry.

The improvements observed for the silicate-free detergents and detergents with a low content of soluble silicate according to the invention with regard to the deposition of residual materials on the washed laundry are confirmed when the described product is tested against a control product which has essentially the same composition, but which does not contain any bentonite , and which contains approx. 8% sodium silicate. In such an assessment, a washing machine of the Whirlpool Suds Saver model is used, using a mild wash cycle and a wash time of 8 minutes. The concentration of the detergent is 0.06%, the washing water has a mixed calcium and magnesium hardness of a total of 200 ppm, calculated as calcium carbonate, and the water temperature is 24° C. The garments that are washed are: 100% cotton,

100% polyester, 85% acetate and 15% nylon, and 65% polyester and 35% cotton. The laundry is examined wet and after drying on a line.No residue is observed in any case. When the control detergent is tested, a moderate residue is observed on all test garments.

The results of the practical test described above for determining the amount of residue are confirmed by weighing the residue deposited on a denim fabric. In this test, the detergent according to the invention is filtered through a sample of denim fabric, the detergent being in solution/suspension of concentration 0.12% in water with a hardness of 200 ppm (calculated as CaCO^) at 24° C. The weight of the residue on the laundry is determined and is compared with the weight found for a control sample. In the test, the percentage of residue compared to the control sample is approx. 75%, which is considered a significant improvement.

The adhesion test, which was previously referred to, and which measures the stickiness of detergent products, is a test where 10 grams of base grain (or detergent, in some cases) is placed evenly between two watch glasses, both of which have a diameter of approx. 23 cm; placing a 500 gram weight on top of the upper watch glass (both watch glasses have the concave side up). After a delay of approx. After 5 minutes, the solder and the upper watch glass are removed, and the lower watch glass is turned over, after which the amount of product still adhering to the watch glass is weighed. The percentage adhesion is the number of grams of product that remain on the watch glass, divided by 10 and multiplied by 100.

The flow index is that which is measured by a flow test, where the volumetric flow rates of base grain (and in some cases of the final product) and standardized Ottawa sand (-20 +60, according to the U.S. Sieve Series) are compared by measuring the times that takes to completely empty a 1.9 liter Mason jar through a 2.2 cm diameter hole in a nozzle attached to the jar's lid. flow index

then the time measured for the sand flow is divided by the time measured for the product flow, expressed as a percentage.

Example 6

The experiment according to Example 5 is repeated, on a reduced scale, without the polyacrylate being present in the mixing machine mixture. The flow rate through the spray-drying tower decreases significantly, and also the ability of the base grains to absorb non-ionic surfactant is less (or the manufactured product is somewhat stickier, if the same amount of non-ionic surfactant is applied). However, the mixer mixture does not solidify in the mixer, the base granules can be prepared by spray drying, and the detergent obtained, although having a lower content of non-ionic surfactant, e.g. 17% non-ionic surfactant, to maintain flow properties and non-tack, still a usable product with satisfactory flow properties.

Example 7

The procedure described in Example 5 is repeated, with 2% sodium silicate in a quantity ratio of Na20:SiO2 of 1:2.4 being added to the mixing machine in the form of an aqueous solution with 47.5% solids content. The product does not form a gel in the mixing machine under normal manufacturing conditions, but it is desirable to use magnesium sulphate and citric acid as process aids to prevent gel formation or solidification when the residence time is longer than normal. Likewise, the detergent leaves more residue on the washed laundry, which is more easily visible when the laundry is dark-coloured.

Example 8

The experiment according to Example 5 is repeated with the addition of 5% aqueous sodium silicate powder ("Britesil") together with the enzyme powder. Such post-added silicate does not appear to have any significant adverse effect on zeolite deposition on washed laundry, and it helped to prevent corrosion of aluminum parts in the washing machine as well as to soften the water and to act as a softener in the detergent.

Example 9

The procedure according to Example 5 is repeated with only water, zeolite, bentonite, sodium carbonate, sodium bicarbonate and sodium polyacrylate present in the mixer mixture and in the base grains and with the subsequent addition of non-ionic surfactant. The product obtained has satisfactory washing properties, but it is not commercially satisfactory for aesthetic reasons, because it lacks perfume. It also does not wash as well, due to the absence of enzyme, and it does not have the blue tone and clarity promoting effect that the ultramarine blue material and the fluorescent material contribute to in the other detergents.

Claims (3)

1. Detergent, which is useful for washing clothes, and which comprises a particulate, structured, synthetic, non-ionic, organic surfactant which is structured with sodium carbonate, sodium bicarbonate and water softening zeolite, where the mixture of the sodium carbonate, sodium bicarbonate and zeolite is in the form of spray-dried base grains that are free of synthetic surfactant, characterized in that said mixture contains (a) from 15 to 30% by weight of sodium carbonate, (b) from 10 to 22% by weight of sodium bicarbonate, (c) from 10 to 50% by weight of water-softening zeolite, (d) from 0 to 18% by weight % sodium silicate and (e) from 1 to 20% by weight bentonite and/or from 0.05 to 2% by weight polyacrylate of molecular weight in the range from 1000 to 5000 and that in the spray-dried base grains 15 - 30% by weight of a normally solid, nonionic surfactant. 2. Detergent according to claim 1, characterized in that the non-ionic surfactant is a condensation product of from 6 to 12 mol ethylene oxide and a higher fatty alcohol with from 12 to 16 carbon atoms, and that the amount of non-ionic surfactant in the detergent is in the range from 15 to 22% by weight . 3. Detergent according to claim 2, characterized in that the spray-dried base grains have a mass density of from 0.6 to 0.8 g/cm<3> and contain from 20 to 25% by weight sodium carbonate, from 13 to 19% by weight sodium bicarbonate, from 30 to 37% by weight hydrated zeolite , from 5 to 8% by weight of sodium silicate, from 5 to 8% by weight of bentonite, from 0.1 to 2% by weight of sodium polyacrylate with a molecular weight of from 1000 to 5000, and from 4 to 10% by weight of water, disregarding the hydrate water of the zeolite , that the zeolite is "Zeolite A" which has a final mid- , clay particle size in the range from 3 to 12 pm, which has an ion exchange capacity for calcium ions of from 250 to 350 milligram equivalents per grams, and which gives a residual hardness of less than 0.01 mg/l after 10 minutes, that the sodium silicate has a ratio of Na20:SiO2 in the range from 1:2 to 1:2.4, and that the bentonite is an expanded, swelling Wyoming bentonite clay with a swelling capacity in the range from 7 to 15 ml/g and a viscosity in the range from 8 to 30 cp at 6% concentration in water.