CA2315136A1 - Process for the production of preparations containing co-builders - Google Patents

Abstract

The production of powder-form, pourable and free-flowing preparations which contain co-builders and organic and/or inorganic carrier material and are suitable for the production of particulate detergents was to be improved. This was essentially achieved by mixing an oxidized dextrin derivative with inorganic builder, surfactant and water in such a quantity that a mixture flowable and pumpable at temperatures below 80°C is formed and the water is removed from the mixture thus formed by spray drying using drying gases with temperatures in the range from 160°C to 260°C to such an extent that a powder-form free-flowing product is formed.

Description

PROCESS FOR THE PRODUCTION OF PREPARATIONS CONTAINING
CO-BUILDERS
Field of the Invention This invention relates to a process for the production of powder-form, pourable and free-flowing preparations containing certain co-builders and organic and/or inorganic carrier material and to their use as premixes (compounds) for the production of particulate detergents.
Background of the Invention Besides the surfactants essential for cleaning performance, detergents normally also contain so-called builders of which the function is to support the performance of the surfactants by eliminating hardness salts, i.e. essentially calcium and magnesium ions, from the wash liquor so that they are unable to interact negatively with the surfactants. A well-known example of such builders, which improve single wash cycle performance, is zeolite NaA which is known to be capable of forming such stable complexes, particularly with calcium ions, that their reaction with anions responsible for water hardness, particularly carbonate, to form insoluble compounds is suppressed. In addition, builders are intended, particularly in laundry detergents, to prevent redeposition of the soil detached from the fibers or generally from the surface to be cleaned and also insoluble compounds formed by the reaction of cations forming water hardness with anions forming water hardness onto the cleaned laundry or rather the surface. So-called co-builders are normally used for this purpose. Co-builders are generally polymeric polycarboxylates which advantageously have a complexing effect on the cations forming water hardness in addition to the contribution the make towards multiple wash cycle performance.
Particulate detergents generally consist of several separately produced solid components which necessitate different production processes according to their nature of their ingredients. A preferred production process for the builder- and surfactant-containing component of such detergents is the relatively uncomplicated spray drying of a an aqueous solution or slurry of the ingredients. However, this particular process does presuppose heat resistance on the part of the constituents which is guaranteed where hitherto standard builder systems, particularly based on inorganic materials, such as phosphates, zeolites or layer silicates, are used. Even polymeric polycarboxylates, such as the usual polymers synthesized from acrylic acid and malefic acid, and monomeric co-builders, such as alkali metal citrates, can normally be spray-dried without difficulty as a constituent of aqueous slurries in the production of detergents.
If it is intended to use organic co-builders, which may assumed from their molecular composition to be more readily biodegradable than the polymeric polycarboxylates mentioned, the problem arises that these substances in particular lack heat resistance and, when used in conventional spray drying processes, lead to more or less strongly colored powders which cannot be incorporated in particulate detergents. This problem is very pronounced with co-builders based on oligomeric or polymeric saccharides, among which the oxidized dextrin derivatives are particularly mentioned here.
The oxidized derivatives of dextrins are their reaction products with oxidizing agents which are capable of oxidizing at least one alcohol function of the saccharide ring to the carboxylic acid function, dextrins being understood to be oligomers or polymers of carbohydrates obtainable, for example, by partial hydrolysis of starch. The hydrolysis may be carried out by standard methods, for example acid- or enzyme-catalyzed methods.
The end products are preferably oligomers or polymers with average molecular weights of 440 to 500,000 or with dextrose equivalents (DE) of 0.5 to 40 and, more particularly, 2 to 30, the DE being an accepted measure of the reducing effect of a polysaccharide by comparison with dextrose which has a DE of 100. Both maltodextrins (DE 3 to 20) and dry glucose sirups (DE 20 to 37) and also so-called yellow dextrins and white dextrins with relatively high molecular weights of ca. 2,000 to 30,000 may be used. A preferred dextrin is described in European patent application EP 0 703 292. Oxidized dextrins obtainable from these dextrins and processes for their production are known, for example, from European patent applications EP 0 427 349, EP 0 472 042 and EP 0 542 496 and from International patent applications WO 93108251, WO 93116110, WO
95107303 and WO 95/12619. A product oxidized at C6 of the saccharide ring obtainable by the process according to any of International patent applications WO 93116110, WO 94/28030, WO 95/20608 and WO
96103429 is preferably used. In addition, however, preference is also attributed above all to the use of dextrins which have been oxidatively modified at their originally reducing end with the loss of 1 carbon atom. If the originally reducing end of the oligosaccharide was an anhydroglucose unit, an arabinonic acid unit is present after the modification:
(glucose)+~ ~ (glucose)n arabinonic acid.
In these dextrins, the average degree of oligomerization n, which as an analytically determined quantity may also be a broken number, is preferably in the range from 2 to 20 and more preferably in the range from 2 to 10. This oxidative modification may be carried out, for example, using Fe, Cu, Ag, Co or Ni catalysts as described in International patent application WO 92118542, using Pd, Pt, Rh or Os catalysts as described in European patent EP 0 232 202 or using a quinone/hydroquinone system in the alkaline range in conjunction with oxygen, optionally followed by aftertreatment with hydrogen peroxide.
Summary of the Invention The present invention relates to a process for the production of powder-form, pourable and free-flowing preparations which contain co-builders and organic and/or inorganic carrier material and are suitable for the production of particulate detergents by drying flowable, aqueous, surfactant-containing mixtures of their constituents, characterized in that an oxidized dextrin derivative is mixed with inorganic builder, surfactant and water in such a quantity that a mixture flowable and pumpable at temperatures below 80°C is formed and the water is removed from the mixture thus formed by spray drying using drying gases with temperatures in the range from 160°C to 260°C to such an extent that a powder-form free-flowing product is formed. This is normally the case at water contents of the powder product of about 2% by weight to 15% by weight, water contents being understood here to be contents of water which can be removed by heating to temperatures of up to 200°C.
The expression "carrier material" used here is intended to designate the other ingredients besides the co-builder essential to the invention which are present in the powder-form preparation. These other ingredients may be selected from all the usual ingredients of detergents which do not interact unreasonably with the co-builder essential to the invention during production or subsequent storage and which withstand the spray drying process without an unreasonable loss of activity. The quantities in which the other ingredients are present will largely be determined by the fact that the preparation obtained by the process according to the invention must be a powder-form preparation. Accordingly, the ingredients solid at room temperature will generally represent by far the greatest part of the carrier material.
Detailed Description of the Invention Of these ingredients, inorganic builders are mentioned first and foremost, i.e. in particular zeolites, silicates, carbonates and - providing there are no ecological objections to their use - the phosphates. Inorganic builders such as these are present in the compounds produced by the process according to the invention in quantities of preferably 25% by weight to 75% by weight and more preferably 30% by weight to 65% by weight.

5 The finely crystalline, synthetic detergent-range zeolite containing bound water used in accordance with the invention is preferably zeolite A
and/or zeolite P. Zeolite MAP~ (Crosfield) is a particularly preferred P-type zeolite. However, zeolite X and mixtures of A, X and/or P are also suitable.
According to the invention, it is preferred to use, for example, a commercially obtainable co-crystallizate of zeolite X and zeolite A (ca. 80%
by weight zeolite X) which is marketed by CONDEA Augusta S.p.A. under the name of VEGOBOND AX~ and which may be described by the following formula:
nNa20 ~ (1-n)K20 ~ AI203 ~ (2 - 2.5)Si02 ~ (3.5 - 5.5) H20.
Suitable zeolites preferably have a mean particle size of less than 10 ~,m and contain preferably 18 to 22% by weight and more preferably 20 to 22%
by weight of bound water.
Suitable crystalline layer-form sodium silicates correspond to the general formula Na2MSiX02x+~~yH20, where M is sodium or hydrogen, x is a number of 1.9 to 4 and y is a number of 0 to 20, preferred values for x being 2, 3 or 4. Crystalline layer silicates such as these are described, for example, in European patent application EP-A-0 164 514. Preferred crystalline layer silicates corresponding to the above formula are those in which M is sodium and x assumes the value 2 or 3. Both ~- and ~-sodium disilicates Na2Si205~yH20 are particularly preferred, ~3-sodium disilicate being obtainable, for example, by the process described in International patent application WO 91/08171.

Amorphous sodium silicates with a modulus (Na20:Si02 ratio) of 1:2 to 1:3.3, preferably 1:2 to 1:2.8 and more preferably 1:2 to 1:2.6 which dissolve with delay and exhibit multiple wash cycle properties may also be used. The delay in dissolution in relation to conventional amorphous sodium silicates can have been obtained in various ways, for example by surface treatment, compounding, compacting or by overdrying. In the context of the invention, the term "amorphous" is also understood to encompass "X-ray amorphous". In other words, the silicates do not produce any of the sharp X-ray reflexes typical of crystalline substances in X-ray diffraction experiments, but at best one or more maxima of the scattered X-radiation which have a width of several degrees of the diffraction angle. Particularly good builder properties may even be achieved where the silicate particles produce crooked or even sharp diffraction maxima in electron diffraction experiments. This may be interpreted to mean that the products have microcrystalline regions between 10 and a few hundred nm in size, values of up to at most 50 nm and, more particularly, up to at most 20 nm being preferred. So-called X-ray amorphous silicates such as these, which dissolve with delay compared with the conventional waterglasses, are described, for example, in German patent application DE 44 00 024. Compacted amorphous silicates, compounded amorphous silicates and overdried X-ray-amorphous silicates are particularly preferred.
The generally known phosphates may of course also be used as builders providing their use should not be avoided on ecological grounds.
Among the large number of commercially available phosphates, alkali metal phosphates have the greatest importance in the detergent industry, pentasodium triphosphate and pentapotassium triphosphate (sodium and potassium tripolyphosphate) being particularly preferred.
"Alkali metal phosphates" is the collective term for the alkali metal (more particularly sodium and potassium) salts of the various phosphoric acids, including metaphosphoric acids (HP03)" and orthophosphoric acid (H3P04) and representatives of higher molecular weight. The phosphates combine several advantages: they act as alkalinity sources, prevent lime deposits on machine parts and lime incrustations in fabrics and, in addition, contribute towards the cleaning effect.
If desired, other organic co-builders, more particularly polycarboxylates/polycarboxylic acids, polymeric polycarboxylates, polymeric aspartic acid, polyacetals and phosphonates, may be used in addition to the oxidized dextrin. Co-builders belonging to these classes are described in the following although their use in the process according to the invention is not preferred. In a preferred embodiment of the invention, other organic co-builders are only used in small quantities by comparison with the oxidized dextrin derivative. Another preferred embodiment of the invention is characterized by the complete absence of, in particular, the polycarboxylates/polycarboxylic acids mentioned below .
Suitable organic builders are, for example, polycarboxylic acids usable in the form of their sodium salts, polycarboxylic acids being understood to be carboxylic acids which bear more than one acid function.
Examples of such polycarboxylic acids include citric acid, adipic acid, succinic acid, glutaric acid, malic acid, tartaric acid, malefic acid, fumaric acid, sugar acids, aminocarboxylic acids, nitrilotriacetic acid (NTA), providing their use is not ecologically unsafe, and mixtures thereof. The acids per se may also be used. Besides their builder effect, the acids also typically have the property of an acidifying component and, hence, also serve to establish a relatively low and mild pH value in detergents. Citric acid, succinic acid, glutaric acid, adipic acid, gluconic acid and mixtures thereof are particularly mentioned in this regard.
Other suitable co-builders are polymeric polycarboxylates such as, for example, the alkali metal salts of polyacrylic or polymethacrylic acid, for example those with a relative molecular weight of 500 to 70,000 g/mole.
The molecular weights mentioned in this specification for polymeric polycarboxylates are weight-average molecular weights MW of the particular acid form which, basically, were determined by gel permeation chromatography (GPC) using a UV detector. The measurement was carried out against an external polyacrylic acid standard which provides realistic molecular weight values by virtue of its structural similarity to the polymers investigated. These values differ distinctly from the molecular weights measured against polystyrene sulfonic acids as standard. The molecular weights measured against polystyrene sulfonic acids are generally higher than the molecular weights mentioned in this specification.
Particularly suitable polymers are polyacrylates which preferably have a molecular weight of 2,000 to 20,000 g/mole. By virtue of their superior solubility, preferred representatives of this group are the short-chain polyacrylates which have molecular weights of 2,000 to 10,000 g/mole and, more particularly, 3,000 to 5,000 g/mole.
Also suitable are copolymeric polycarboxylates, particularly those of acrylic acid with methacrylic acid and those of acrylic acid or methacrylic acid with malefic acid. Acrylic acid/maleic acid copolymers containing 50 to 90% by weight of acrylic acid and 50 to 10% by weight of malefic acid have proved to be particularly suitable. Their relative molecular weights, based on the free acids, are generally in the range from 2,000 to 70,000 g/mole, preferably in the range from 20,000 to 50,000 g/mole and more preferably in the range from 30,000 to 40,000 g/mole.
The (co)polymeric polycarboxylates may be used either in powder form or in the form of an aqueous solution. The content of (co)polymeric polycarboxylates in the detergent, if desired, is from 0.5 to 20% by weight and more preferably from 3 to 10% by weight.

In order to improve solubility in water, the polymers may also contain allyl sulfonic acids, such as allyloxybenzene sulfonic acid and methallyl sulfonic acid, as monomer.
Other particularly preferred polymers are biodegradable polymers of more than two different monomer units, for example those which contain salts of acrylic acid and malefic acid and vinyl alcohol or vinyl alcohol derivatives as monomers or those which contain salts of acrylic acid and 2-alkylallyl sulfonic acid and sugar derivatives as monomers.
Other preferred copolymers are those which are described in German patent applications DE-A-43 03 320 and DE-A-44 17 734 and which preferably contain acrolein and acrylic acid/acrylic acid salts or acrolein and vinyl acetate as monomers.
Other preferred builders are polymeric aminodicarboxylic acids, salts or precursors thereof. Particular preference is attributed to polyaspartic acids or salts and derivatives thereof which, according to German patent application DE-A-195 40 086, are also said to have a bleach-stabilizing effect in addition to their co-builder properties.
Other suitable builders are polyacetals which may be obtained by reaction of dialdehydes with polyol carboxylic acids containing 5 to 7 carbon atoms and at least three hydroxyl groups. Preferred polyacetals are obtained from dialdehydes, such as glyoxal, glutaraldehyde, terephthal-aldehyde and mixtures thereof and from polyol carboxylic acids, such as gluconic acid and/or glucoheptonic acid.
Other suitable co-builders are oxydisuccinates and other derivatives of disuccinates, preferably ethylenediamine disuccinate. Ethylenediamine-N,N'-disuccinate (EDDS) is preferably used in the form of its sodium or magnesium salts. Glycerol disuccinates and glycerol trisuccinates are also preferred in this connection. The quantities used in zeolite-containing and/or silicate-containing formulations, if desired, are from 3 to 15% by weight.
Other useful organic co-builders are, for example, acetylated hydroxycarboxylic acids and salts thereof which may optionally be present in lactone form and which contain at least 4 carbon atoms, at least one 5 hydroxy group and at most two acid groups. Co-builders such as these are described, for example, in International patent application WO-A-95/20029.
Another class of substances with co-builder properties are the phosphonates, more particularly hydroxyalkane and aminoalkane phos-phonates. Among the hydroxyalkane phosphonates, 1-hydroxyethane-1,1-10 diphosphonate (HEDP) is particularly important as a co-builder. It is preferably used in the form of the sodium salt, the disodium salt showing a neutral reaction and the tetrasodium salt an alkaline reaction (pH 9).
Preferred aminoalkane phosphonates are ethylenediamine tetramethylene phosphonate (EDTMP), diethylenetriamine pentamethylenephosphonate (DTPMP) and higher homologs thereof. They are preferably used in the form of the neutrally reacting sodium salts, for example as the hexasodium salt of EDTMP or as the hepta- and octasodium salts of DTPMP. Of the phosphonates, HEDP is preferably used as a builder. In addition, the aminoalkane phosphonates have a pronounced heavy metal binding capacity. Accordingly, it can be of advantage, particularly where the detergents also contain bleach, to use aminoalkane phosphonates, more particularly DTPMP, or mixtures of the phosphonates mentioned.
In addition, any compounds capable of forming complexes with alkaline earth metal ions may be used as co-builders.
The quantity of builder component, i.e. the sum of builder and co-builder, including the oxidized dextrin derivative essential to the invention, in the compound produced in accordance with the invention is normally between 40 and 80% by weight, preferably between 45 and 70% by weight and more preferably between 50 and 65% by weight. The oxidized dextrin preferably makes up 5% by weight to 50% by weight and more preferably 10% by weight to 25% by weight of the builder component as a whole.
In addition, the aqueous slurries to be spray dried in acordance with the invention contain a surfactant which may be selected from anionic, nonionic, cationic and/or amphoteric surfactants or mixtures thereof.
Mixtures of anionic and nonionic surfactants are preferred from the performance perspective. The total surfactant content of the compounds produced by the process according to the invention is preferably in the range from 5% by weight to 30% by weight and more preferably in the range from 7% by weight to 25% by weight.
The anionic surfactants used are, for example, those of the sulfonate and sulfate type. Suitable surfactants of the sulfonate type are preferably C9_~3 alkyl benzenesulfonates, olefin sulfonates, i.e. mixtures of alkene and hydroxyalkane sulfonates, and the disulfonates obtained, for example, from C~2_~a monoolefins with an internal or terminal double bond by sulfonation with gaseous sulfur trioxide and subsequent alkaline or acidic hydrolysis of the sulfonation products. Other suitable surfactants of the sulfonate type are the alkane sulfonates obtained from C~2_~8 alkanes, for example by sulfochlorination or sulfoxidation and subsequent hydrolysis or neutralization. The esters of a-sulfofatty acids (ester sulfonates), for example the a-sulfonated methyl esters of hydrogenated coconut oil, palm kernel oil or tallow fatty acids, are also suitable.
Other suitable anionic surfactants are sulfonated fatty acid glycerol esters, i.e. the monoesters, diesters and triesters and mixtures thereof which are obtained where production is carried out by esterification of a monoglycerol with 1 to 3 moles of fatty acid or in the transesterification of triglycerides with 0.3 to 2 moles of glycerol. Preferred sulfonated fatty acid glycerol esters are the sulfonation products of saturated fatty acids containing 6 to 22 carbon atoms, for example caproic acid, caprylic acid, capric acid, myristic acid, lauric acid, palmitic acid, stearic acid or behenic acid.
Preferred alk(en)yl sulfates are the alkali metal salts and, in particular, the sodium salts of the sulfuric acid semiesters of C~2_~$ fatty alcohols, for example coconut alcohol, tallow alcohol, lauryl, myristyl, cetyl or stearyl alcohol, or Coo-2o oxoalcohols and the corresponding semiesters of secondary alcohols with the same chain length. Other preferred alk(en)yl sulfates are those with the chain length mentioned which contain a synthetic, linear alkyl chain based on a petrochemical and which are similar in their degradation behavior to the corresponding compounds based on oleochemical raw materials. C~2_~s alkyl sulfates and C~2_~5 alkyl sulfates and also C~4-15 alkyl sulfates alkyl sulfates are particularly preferred from the washing performance point of view. Other suitable anionic surfactants are 2,3-alkyl sulfates which may be produced, for example, in accordance with US 3,234,258 or US 5,075,041 and which are commercially obtainable as products of the Shell Oil Company under the name of DAN~.
The sulfuric acid monoesters of linear or branched C~_2~ alcohols ethoxylated with 1 to 6 moles of ethylene oxide, such as 2-methyl-branched C9_~~ alcohols containing on average 3.5 moles of ethylene oxide (EO) or C~2_1g fatty alcohols containing 1 to 4 EO, are also suitable. In view of their high foaming capacity, they are normally used in only relatively small quantities, for example in quantities of 1 to 5% by weight, in detergents.
Other suitable anionic surfactants are the salts of alkyl sulfosuccinic acid which are also known as sulfosuccinates or as sulfosuccinic acid esters and which represent monoesters and/or diesters of sulfosuccinic acid with alcohols, preferably fatty alcohols and, more particularly, ethoxylated fatty alcohols. Preferred sulfosuccinates contain C8_~$ fatty alcohol molecules or mixtures thereof. Particularly preferred sulfosuccinates contain a fatty alcohol molecule derived from ethoxylated fatty alcohols which, considered in isolation, represent nonionic surfactants (for a description, see below). Of these sulfosuccinates, those of which the fatty alcohol molecules are derived from narrow-range ethoxylated fatty alcohols are particularly preferred. Alk(en)yl succinic acid preferably containing 8 to 18 carbon atoms in the alk(en)yl chain or salts thereof may also be used.
Other suitable anionic surfactants are, in particular, soaps. Suitable soaps are, in particular, saturated fatty acid soaps, such as the salts of lauric acid, myristic acid, palmitic acid, stearic acid, hydrogenated erucic acid and behenic acid, and soap mixtures derived in particular from natural fatty acids, for example coconut, palm kernel or tallow acids.
The anionic surfactants, including the soaps, may be present in the form of their sodium, potassium or ammonium salts and as soluble salts of organic bases, such as mono-, di- or triethanolamine. The anionic surfactants are preferably present in the form of their sodium or potassium salts and, more preferably, in the form of their sodium salts.
Preferred nonionic surfactants are alkoxylated, advantageously ethoxylated, more particularly primary alcohols preferably containing 8 to 18 carbon atoms and an average of 1 to 12 moles of ethylene oxide (EO) per mole of alcohol, in which the alcohol radical may be linear or, preferably, 2-methyl-branched or may contain linear and methyl-branched radicals in the form of the mixtures typically present in oxoalcohol radicals.
However, alcohol ethoxylates containing linear radicals of alcohols of native origin with 12 to 18 carbon atoms, for example coconut alcohol, palm oil alcohol, tallow alcohol or oleyl alcohol, and an average of 2 to 8 EO per mole of alcohol are particularly preferred. Preferred ethoxylated alcohols include, for example, C~2_~4 alcohols containing 3 EO or 4 EO, C9_~~ alcohol containing 7 EO, C~3_~5 alcohols containing 3 EO, 5 EO, 7 EO or 8 EO, C~2_~8 alcohols containing 3 EO, 5 EO or 7 EO and mixtures thereof, such as mixtures of C~2_~a alcohol containing 3 EO and C~2_~$ alcohol containing EO. The degrees of ethoxylation mentioned are statistical mean values which, for a special product, may be either a whole number or a broken 5 number. Preferred alcohol ethoxylates have a narrow homolog distribution (narrow range ethoxylates, NRE). In addition to these nonionic surfactants, fatty alcohols containing more than 12 EO may also be used, as described above. Examples of such fatty alcohols are (tallow) fatty alcohols containing 14 EO, 25 EO, 30 EO or 40 EO.
In addition, other nonionic surfactants which may be used are alkyl glycosides with the general formula RO(G)X where R is a primary, linear or methyl-branched, more particularly 2-methyl-branched, aliphatic radical containing 8 to 22 and preferably 12 to 18 carbon atoms and G is a glycose unit containing 5 or 6 carbon atoms, preferably glucose. The degree of oligomerization x, which indicates the distribution of monoglycosides and oligoglycosides, is a number of 1 to 10 and preferably a number of 1.2 to 1.4.
Nonionic surfactants of the amine oxide type, for example N-cocoalkyl-N,N-dimethylamine oxide and N-tallowalkyl-N,N-dihydroxyethyl amine oxide, and the fatty acid alkanolamide type are also suitable. The quantity in which these nonionic surfactants are used is preferably no more, in particular no more than half, the quantity of ethoxylated fatty alcohols used.
Other suitable surfactants are polyhydroxyfatty acid amides cor-responding to formula (II):
R' R-CO-N-[Z] (I I) in which RCO is an aliphatic acyl group containing 6 to 22 carbon atoms, R' is hydrogen, an alkyl or hydroxyalkyl group containing 1 to 4 carbon atoms and [Z] is a linear or branched polyhydroxyalkyl group containing 3 to 10 carbon atoms and 3 to 10 hydroxyl groups. The polyhydroxyfatty acid amides are known substances which are normally obtained by reductive 5 amination of a reducing sugar with ammonia, an alkylamine or an alkanolamine and subsequent acylation with a fatty acid, a fatty acid alkyl ester or a fatty acid chloride.
The group of polyhydroxyfatty acid amides also includes compounds corresponding to formula (III):
R~-O-R2 (III) R-CO-N-[Z]
in which R is a linear or branched alkyl or alkenyl group containing 7 to 12 carbon atoms, R' is a linear, branched or cyclic alkyl group or an aryl group containing 2 to 8 carbon atoms and R2 is a linear, branched or cyclic alkyl group or an aryl group or a hydroxyalkyl group containing 1 to 8 carbon atoms, C~_4 alkyl or phenyl groups being preferred, and [Z] is a linear polyhydroxyalkyl group, of which the alkyl chain is substituted by at least two hydroxyl groups, or alkoxylated, preferably ethoxylated or propoxylated, derivatives of such a group. [Z] is preferably obtained by reductive amination of a reduced sugar, for example glucose, fructose, maltose, lactose, galactose, mannose or xylose. The N-alkoxy or N-aryloxy-substituted compounds may then be converted into the required polyhydroxyfatty acid amides by reaction with fatty acid methyl esters in the presence of an alkoxide as catalyst, for example in accordance with the teaching of International patent application WO-A-95107331.
According to the invention, the procedure preferably adopted is characterized in that 1 part by weight to 5 parts by weight, more particularly 2 parts by weight to 4 parts by weight, of surfactant, more particularly anionic surfactant, 2 parts by weight to 15 parts by weight, more particularly parts by weight to 10 parts by weight, of inorganic builder, 1 part by weight of oxidized dextrin derivative and optionally other sprayable 5 detergent ingredients are mixed with water in such a quantity that a pumpable and transportable slurry is obtained and is then spray dried, i.e.
after the aqueous slurry has been atomized into small droplets, it is contacted with hot drying gas. The powder products formed from the sprayed droplets preferably never reach temperatures higher than 120°C.
The aqueous slurries to be spray dried preferably contain no optical brightener, above all no diaminostilbene disulfonic acids or Biphenyl styryls, because in their presence the color impression of the powders formed is not optimal.
The aqueous slurries are spray dried in so-called spray towers in the upper part of which the slurry is sprayed through pressure nozzles to form fine droplets which move under the effect of gravity into the lower part of the spray tower, coming into contact with hot drying gases flowing in co-current with or preferably in countercurrent to the particles to be dried. It is important to ensure that the temperature of the drying gases is not too high. In the context of the invention, this means that the temperature of the drying gases does not exceed 260°C and is preferably in the range from 160°C to 240°C and more preferably in the range from 180°C to 220°C, the temperature of the drying gas being measured at the hottest point of the spray tower, the so-called ring channel.
The compounds produced in accordance with the invention may be converted into the corresponding end products by mixing with other particulate constituents of detergents, more particularly bleaching agents, bleach activators, particulate enzymes, such as proteases, amylases, lipases, cellulases and mixtures thereof, particulate foam regulators or perfumes (so-called perfume beads). Liquid ingredients, including in particular nonionic surfactants and perfumes and optical brighteners optionally mixed with water and/or nonionic surfactant, may be sprayed onto the compounds produced in accordance with the invention beforehand or during the mixing process. The compounds produced in accordance with the invention may also be subjected to a compacting aftertreatment, optionally in admixture with other ingredients. Detergents of high bulk density, more particularly in the range from 650 to 950 g/I, are preferably produced by the process comprising an extrusion step which is known from European patent EP 0 486 592. Another preferred production process is the granulation process according to European patent EP 0 642 576. To produce detergents in the form of tablets which comprise one or more phases and are colored in one or more colors and, in particular, may consist of one layer or several layers, more particularly two layers, all the ingredients - optionally for each layer - may be mixed together in a mixer and the resulting mixture tabletted in conventional tablet presses, for example eccentric presses or rotary presses. In the case of multilayer tablets in particular, it can be of advantage if at least one layer is compressed in advance. A tablet produced in this way preferably has a weight of 10 g to 50 g and, more particularly, 15 g to 40 g. The tablets may be of any shape, including round, oval or angular and variations thereof.
Corners and edges are advantageously rounded off. Round tablets preferably have a diameter of 30 mm to 40 mm.
ExamQles Aqueous slurries S1, S2 and S3 were produced from the raw materials listed in Table 1. These slurries were heated to temperatures of about 60°C to 80°C and sprayed under pressure into a drying tower through which hot air (temperature ca. 200°C in the ring channel) flowed in countercurrent to the slurries. Free-flowing powders M1, M2 and M3 with mean particle sizes of around 300 pm were obtained. The powders were free from particles above 1.6 mm in diameter, contained at most 1 % by weight of dust (diameter < 0.1 mm) and had the water contents (H20; % by weight), bulk densities (BD; g/I) and standard color values (Y) shown in Table 2.
Table 1:1:
Composition [kq] of the aaueous slurries Na alkyl benzenesulfonate 326 252 273 7x-Ethoxylated fatty alcohol- 16 58 Caustic soda 116 91 87 Fatty acid 28 22.5 20 Zeolite NaA 1833 1411 801 Sodium silicate 1 83.5 126 Oxidized dextrin 280 224 170 Sodium carbonate 160 108 74 Sod iu m su Ifate 162 544 352 Phosphonate 17 14 -Polyvinyl pyrrolidone - - 25 Water to 2000to 2000 to 2000 Table 2 M 13.7 390 72.42 M2 7.5 480 76.16 M3 7 424 72.08 The invention may be varied in any number of ways as would be apparent to a person skilled in the art and all obvious equivalents and the like are meant to fall within the scope of this description and claims. The description is meant to serve as a guide to interpret the claims and not to limit them unnecessarily.

Claims (10)

1. A process for the production of powder-form, pourable and free-flowing preparations which contain co-builders and organic and/or inorganic carrier material and are suitable for the production of particulate detergents by drying flowable, aqueous, surfactant-containing mixtures of their constituents, characterized in that an oxidized dextrin derivative is mixed with inorganic builder, surfactant and water in such a quantity that a mixture flowable and pumpable at temperatures below 80°C is formed and the water is removed from the mixture thus formed by spray drying using drying gases with temperatures in the range from 160°C to 260°C
to such an extent that a powder-form free-flowing product is formed.

2. A process as claimed in claim 1, wherein the oxidized dextrin makes up 5% by weight to 50% by weight of the builder component as a whole.

3. A process as claimed in claim 2, wherein the range is 10% by weight to 25% by weight.

4. A process as claimed in claim 1, 2 or 3, wherein a dextrin oxidatively modified at its originally reducing end, optionally with the loss of a carbon atom, is used as the dextrin derivative.

5. A process as claimed in any of claims 1 to 4, wherein the dextrin derivative has the formula (glucose)N-1 arabinonic acid, the average degree of oligomerization n being from 2 to 20.

6. A process as claimed in claim 5, wherein n is from 2 to 10.

7. A process as claimed in any of claims 1 to 6, wherein drying gases with temperatures of 160°C to 240°C are used.

8. A process as claimed in claim 7, wherein the temperatures are in the range of from 180°C to 220°C.

9. A powder-form preparation produced by the process claimed in any of claims 1 to 8 and suitable for the production of particulate detergents, characterized in that it contains inorganic builder in quantities of 25% by weight to 75% by weight and/or surfactant in quantities of 5% by weight to 30% by weight.

10. A preparation as claimed in claim 9, wherein the builder is present in quantities of 30% by weight to 65% by weight and the surfactant in quantities of 7% by weight to 25% by weight.