EP0605436B1 - Process for the production of granular zeolites - Google Patents

Abstract

The aim of the invention is to provide a process for the production of dense granular zeolites, the amount of granulation liquid used representing less than the critical amount already known in the art, thus enabling (co)polymeric carboxylates to be used as the dissolved constituent of the granulation liquid. In the process proposed, granular materials consisting of a zeolite and sodium or potassium salts of polymeric or copolymeric carboxylic acids, with a bulk density of 750 to 1000 g/l, are produced by granulation with the addition of a granulation liquid, part of the zeolite being added in spray-dried form and at least 90 % of the zeolite particles having a diameter of between 50 and 700 νm, and the granulation liquid containing a mixture of water, zeolite and (co)polymeric carboxylates.

Description

The invention relates to a process for the production of zeolite granules with a high bulk density, which have an adsorption capacity for liquid active substances, and the use of the zeolite granules as a preliminary product for the production of detergents and cleaning agents.

From German patent application 33 16 513 (Benckiser), granules are already known which have been produced by spray drying aqueous slurries and contain finely powdered zeolites and salts of (co) polymeric carboxylic acids. They have a bulk density of only 560 to 610 g / l. Granules which contain zeolites, salts of (co) polymeric carboxylic acids and additionally small amounts of alkali metal silicates and which serve as carrier material for liquid detergent components, in particular for nonionic surfactants, are described in German patent application 34 44 960. The bulk density of these granules produced by spray drying is a maximum of 700 g / l and is preferably between 500 and 650 g / l.

European patent application 21 267 (PQ) discloses granules containing zeolites and alkali silicates which have a particle size between 0.15 and 2 mm and a bulk density of 300 to 700 g / l. They are also suitable for adsorbing liquid detergent components, especially nonionic surfactants. To prepare them, a dry premix of zeolite and alkali metal silicate (mixing ratio 1: 1 to 1: 8) is sprayed with water in a granulator and agglomerated, after which the excess water is removed to a residual proportion of less than 5% by weight by drying . The main disadvantage is the high content of strongly alkaline-reacting alkali silicates, which severely limits the use of these granules in detergents which are neutral to weakly alkaline and suitable for sensitive textiles. In addition, according to the teachings of this document, bulk densities of over 700 g / l cannot be achieved. The European patent application 149 264 (Unilever) teaches that commercially available spray-dried zeolites or mixtures thereof with inorganic salts, such as sodium sulfate, can be used to adsorb liquid detergent constituents, in particular nonionic surfactants. The bulk density of the relatively finely divided spray products is in the range from 450 to 600 g / l, the particles having a size between 0.05 and 0.5 mm.

German patent application 38 38 086 describes the production of granules from zeolite and the sodium or potassium salts of polymeric or copolymeric carboxylic acids, the agglomeration or granulation taking place with the addition of a granulating liquid and the agglomerate obtained until a free-flowing granulate is reached a bulk density of 750 to 1,000 g / l is dried. This is based on a homogeneous powdery mixture of a zeolite, which consists of at least 80% of particles with a size of less than 10 »m, and the salt of the (co) polymeric carboxylic acids and granulates them in a further mixing and granulation stage with the addition of water, which is preferably sprayed onto the powder mixture kept in motion. The polycarboxylates are presented in solid form and are not added in dissolved form as a constituent of the granulating liquid, since the amount of granulating liquid used is a critical factor and must therefore be metered exactly. Excessive amounts of granulating liquid lead to granules with a wide grain spectrum and an undesirably high coarse fraction (particle size above 2 mm length) as well as a lower bulk density.

It has now been found that the amount of granulating liquid is a much smaller critical factor, so that the (co) polymeric carboxylates can be used as a dissolved component of the granulating liquid if certain process steps are followed.

The invention relates to a process for the production of granules from zeolite and sodium or potassium salts of polymeric or copolymeric carboxylic acids, the granulation being carried out with the addition of a granulating liquid and the granules obtained until a free-flowing granulate having a bulk density of 750 to 1,000 is reached g / l is dried, which is characterized in that part of the zeolite in spray-dried Form is submitted, wherein at least 90% of the zeolite particles have a diameter between 50 and 700 »m, and the granulating liquid contains a mixture of water, zeolite and (co) polymeric carboxylates.

In the preparation of the granules, it is expedient to start from spray-dried zeolite, which generally has a water content of 17 to 25% by weight and is of detergent quality. Suitable zeolites are those of the zeolite A type. Mixtures of zeolite NaA and NaX can also be used, the proportion of the zeolite NaX in such mixtures advantageously being less than 30%. The zeolite in spray-dried, solid form preferably consists of at least 90% of particles between 100 and 600 »m in size. The preferred average particle diameter (volume distribution, measurement method: Coulter Counter) is between 200 and 500 »m and in particular between 250 and 400» m. In particular, those zeolite powder mixtures are preferred which consist of 70 to 95% by weight of water-containing zeolite, have a bulk density between 350 and 600 g / l and a small amount of additives such as sodium sulfate, salts of nitrilotriacetic acid, sodium hydroxide, carboxymethyl cellulose and methyl cellulose, in particular mixtures of carboxymethyl cellulose and methyl cellulose, polymeric polycarboxylates, in particular homopolymers and copolymers of acrylic acid, or nonionic surfactants. Particularly suitable here are the products commercially available under the name Wessalith ^(R) (products from Degussa).

The zeolite used in the granulating liquid is in particular a finely divided zeolite which consists of at most 10% of particles larger than 30 »m and in particular at least 80% of particles smaller than 10» m. In a preferred embodiment, this in particular finely divided zeolite is used in the form of a 45 to 55% by weight aqueous suspension. It is preferred that the granulating liquid contains 10 to 50% by weight and in particular 15 to 30% by weight and with particular advantage up to 25% by weight of this aqueous zeolite suspension. The water content of the suspension as well as the water content of the suspended and the initially introduced zeolite are included in the calculation of the water balance; the amount of water to be introduced into the granulation stage can be reduced by these shares. The zeolite suspensions used usually additionally contain about 1.5 to 3% by weight, based on the suspension, of stabilizers, which include nonionic surfactants, anionic surfactants, bentonites, smectites or polymeric polycarboxylates. The granules which are produced by the process according to the invention preferably contain 55 to 95% by weight, in particular 60 to 92% by weight, based on the dried granules, of water-containing zeolite. In this case, preferably 1 to 20% by weight and in particular 1.5 to 10% by weight of water-containing zeolite, based on the total amount of water-containing zeolite, is introduced into the granulating liquid as an aqueous suspension.

Suitable water-soluble salts of the homopolymeric and / or copolymeric carboxylic acids contained in the granules, of which the sodium salts are preferred, are polyacrylic acid, polymethacrylic acid and polymaleic acid with preference for polyacrylic acid and polymaleic acid, copolymers of acrylic acid or methacrylic acid with maleic acid or vinyl ethers such as vinyl methyl ether or vinyl ethyl ether , also with vinyl esters such as vinyl acetate or vinyl propionate, acrylamide, methacrylamide and with ethylene, propylene or styrene. In those copolymeric acids in which one of the components has no acid function, the proportion thereof in the interest of sufficient water solubility is not more than 50 mol%, preferably less than 30 mol%. Copolymers of acrylic acid and methacrylic acid with maleic acid have proven to be particularly suitable. Copolymers containing 50 to 90% by weight of acrylic acid and 50 to 10% by weight of maleic acid are particularly preferred. The relative molecular weight of the homo- or copolymeric polycarboxylates is generally 2,000 to 150,000, preferably 5,000 to 100,000. The polycarboxylates are preferably in the form of 30 to 50% by weight, in particular 35 to 45% by weight aqueous solutions used. The granulating liquid preferably contains 10 to 40% by weight of (co) polymeric carboxylates. For the purpose of lowering the viscosity, water-soluble inorganic salts, for example sodium sulfate, can be added to these solutions in amounts of up to 10% by weight, based on the polycarboxylate used. In a further embodiment, the polycarboxylates are initially presented in powder form together with the finely divided zeolite. It is preferred to use a maximum of 50% by weight and in particular a maximum of 40% by weight of the polymeric carboxylates in powder form. The commercially available salts of (co) polymeric carboxylic acids in powder form often contain 5 to 15% by weight of moisture. This proportion of water is also included in the calculation of the water balance. In mathematical terms, the proportion of salts in the preparation of the compositions or in the composition of the finished granules is based on anhydrous salt. The dried granules according to the invention preferably contain the salts of the polymeric or copolymeric carboxylic acids in amounts of 2 to 20% by weight and in particular in amounts of 5 to 20% by weight and with particular advantage between 10 and 17% by weight.

The granulating liquid preferably contains 40 to 80% by weight of water as a liquid constituent, polymeric or copolymeric carboxylates and zeolite as solid constituents as stated above, as well as anionic and / or nonionic surfactants and in particular nonionic surfactants which are in liquid form at the granulation temperature. The granulating liquid advantageously consists of 15 to 35% by weight of (co) polymeric carboxylate, 5 to 12% by weight of zeolite (calculated as an anhydrous active substance), 2 to 20% by weight of anionic and / or nonionic surfactants and 45 to 75 wt .-% of water. In particular, the granulating liquid consists of 20 to 32% by weight of (co) polymeric carboxylate, 6 to 10% by weight of zeolite (calculated as an anhydrous active substance), 5 to 15% by weight of nonionic surfactants and 45 up to 65% by weight of water.

The liquid nonionic surfactants used are preferably ethoxylated and / or propoxylated fatty alcohols, with preference for the ethoxylated fatty alcohols, in particular addition products of 2 to 7 moles of ethylene oxide (EO) with linear primary alcohols, such as, for. B. on coconut oil, tallow or oleyl alcohol, or on primary alcohols (oxo alcohols) branched methyl in the 2-position. In particular, C₁₂-C₁₄ alcohols with 3 EO or 4 EO, C₁₃-C₁₅ alcohols with 3, 5 or 7 EO, C₁₂-C₁₈ alcohols with 2, 3, 5 or 7 EO and mixtures of these, such as mixtures of C₁₂ -C₁₄ alcohol with 3 EO and C₁₂-C₁₈ alcohol with 5 EO used. Preferred ethoxylated fatty alcohols are also those with a narrow homolog distribution (narrow range ethoxylates, nre). In addition, alkyl glucosides of the general forms RO (G) _x can be used as nonionic surfactants, in which R denotes a primary straight-chain or aliphatic radical with 8 to 22, preferably 12 to 18, C atoms which is methyl branched in the 2-position and G is the symbol that represents a glucose unit. The degree of oligomerization x, which indicates the distribution of monoglucosides and oligloglucosides, is any number between 1 and 10; x is preferably 1.2 to 1.4. The granulating liquid can contain, for example, alkyl glucosides in amounts of 1 to 10% by weight, the alkyl glucosides preferably being introduced into the granulating liquid as a 20 to 50% by weight aqueous solution or paste.

Suitable anionic surfactants are, for example, the alkali metal salts, sodium or potassium salts, from the class of the sulfonates and sulfates. As surfactants of the sulfonate type come preferably C₉-C₁₃-alkylbenzenesulfonates, especially C₁₂-alkylbenzenesulfonate, and sulfonates based on oleochemicals such as the esters of α-sulfofatty acids, the sulfo group being in its salt form (mono salt), e.g. B. the α-sulfonated methyl ester of hydrogenated coconut, palm kernel or tallow fatty acids into consideration. Also suitable are the readily biodegradable alkanesulfonates obtained from C₁₂-C₁₈ alkanes, for example by sulfochlorination or sulfoxidation with subsequent hydrolysis or neutralization. The sulfonate group is statistically distributed over the entire carbon chain, with the secondary alkanesulfonates predominating. Suitable surfactants of the sulfate type are, for example, the optionally ethoxylated sulfuric acid monoesters from primary alcohols of natural and synthetic origin, i.e. H. from fatty alcohols, such as. B. coconut fatty alcohol, tallow fatty alcohol, oleyl alcohol, lauryl, myristyl, cetyl or stearyl alcohol, or the C₁₀-C₂₀ oxo alcohols, and the sulfuric acid monoesters of secondary alcohols of this chain length, with the sulfuric acid monoesters of the primary alcohols being preferred on a fat-chemical basis. The solid, water-soluble anionic surfactants can be incorporated in the liquid constituents of the granulating liquid in powder form or in paste form. If aqueous surfactant pastes are used, the water content is included in the calculation of the liquid constituents, or the amount of liquid introduced into the granulation stage can be reduced by this amount.

To produce the moist, non-dried granules, 100 parts by weight of the zeolite powder mixture is added or mixed into a homogeneous mixture of zeolite and, if appropriate, powder of the polymeric or copolymeric carboxylic acid granulating liquid in the amount that preferably 15 to 45 parts by weight, in particular 20 to 40 parts by weight and with particular advantage 20 to 32 Parts by weight, based in each case on the moist granules, of liquid constituents are present. The granulation can be carried out batchwise or continuously in conventional mixing and granulating devices. Are suitable for. B. pelletizers, which consist of a horizontally arranged or inclined to the horizontal, cylindrical container, rotates in the longitudinal axis of a shaft equipped with mixing tools and conveyor blades. The granulation liquid can be supplied through the spray nozzle attached to the wall or on the high shaft. If work is carried out continuously, two consecutive mixers can be used, the first mixer being used to produce the dry or, if an aqueous zeolite suspension is used as a component of the granulating liquid, the premix and in the second mixer the granulation with the addition of polycarboxylate-containing and if appropriate, surfactant-containing granulating liquid. Continuous operation is also possible in a mixer, with either the powder streams and / or the powder streams and the zeolite suspension being combined and homogenized in a first mixing section and the mixture after further transport in a subsequent mixing section with the polycarboxylate-containing and optionally surfactant -containing granulating liquid is treated and granulated. The granulating liquid is preferably sprayed onto the mixture kept in motion by means of nozzles. It is possible to spray a mixture of all components of the granulating liquid or individual components in succession, in particular the surfactant-containing components before and after the addition of the polycarboxylate solution. The granulation is generally carried out at normal to moderately elevated temperatures, preferably at temperatures between 20 and 60 ° C., in particular between 30 and 55 ° C., and generally requires a time of 1.5 to 10 minutes.

The drying can be carried out by introducing hot gases in a third mixing section, e.g. B. a fluidized bed, or after the discharge of the granules from the mixer, for example in a vibrating section, a free-fall dryer or in a thin layer on a conveyor belt. Drying in a fluidized bed is preferred, the temperature of the granules preferably being between 60 and 100.degree. The drying is carried out until the water added in the granulation stage is removed to a level of less than 5% by weight, preferably less than 3% by weight, based in each case on the dried granules. In addition, further water components that were originally introduced with the zeolite or a (co) polymeric salt which is not used anhydrous can be removed during drying. Such "over-dried" granules can have application advantages, for example when added to detergents that contain moisture-sensitive active ingredients. However, the dewatering of the zeolite should preferably not be driven below a water content of 18% by weight, based on zeolite, in order to avoid a reduction in activity. The water content of the granules is expediently in a range in which the water-binding capacity of the zeolite is largely saturated, ie in which the zeolite has a total water content of 19 to 22% by weight.

The granules preferably have a bulk density of 780 to 950 g / l, in particular 800 to 920 g / l. Due to their dense packing and their small pore volume, their absorption capacity for liquid or pasty detergent components, especially nonionic surfactants, is somewhat reduced compared to specifically lighter carrier grains, but is still 15 to a maximum of 20% by weight without appreciable impairment of the flowability of the granules. In view of the high packing density and the possibly already contained content of non-ionic surfactants in the granules, this surprisingly high adsorption capacity is completely sufficient for the usual fields of application, in particular for use as a mixture component in detergents and cleaning agents.

The granules obtained by the process according to the invention are distinguished by a very uniform grain spectrum, in which the fine fraction (particle diameter less than 0.1 mm) generally less than 2% and the Coarse fraction (particle diameter greater than 2 mm) is generally up to 20% (sieve analysis). Preferably, the content of particles smaller than 0.2 mm is less than 5%, while the content of coarser particles (larger than 1.6 mm) is not more than 20% and in particular not more than 15%. The coarse and fine particles are sieved. The coarse fractions are ground and mixed into the product, while the fine fractions or the dust are returned to the granulation.

Surprisingly, regardless of their high packing density and their high content of water-insoluble constituents, the granules disintegrate quickly and completely in cold water and do not leave any residues in the washing-up devices of washing machines, i. H. they have a very good induction ability. This advantageous property is also noticeable after impregnation with nonionic surfactants and in a mixture with other powder detergent components.

The granules can be impregnated with liquid detergent constituents which cannot be incorporated into conventional powdered or granular detergents and cleaning agents in other ways or only with a loss of activity. These include foam inhibitors, in particular paraffin hydrocarbons, silicones, silicone resins and bis-acyl-alkylenediamines derived from long-chain fatty acids, and mixtures thereof. Further adsorbable active ingredients are fatty acid alkylolamides and cationic plasticizers, such as quaternary ammonium salts containing long-chain fatty residues, and also fat-dissolving solvents such as terpenes. However, the granules are preferably used as carrier grains for liquid nonionic surfactants and defoamers, in particular paraffin defoamers. Those components which are present in liquid form at room temperature or at the processing temperature between 25 ° C. and about 80 ° C., preferably up to 75 ° C., are considered to be “liquid”. It can be advantageous to heat components that are already liquid at room temperature, but have an undesirably high viscosity, before the impregnation of the carrier grains.

Suitable nonionic surfactants are alkoxylation products with 10 to 20 carbon atoms in the hydrophobic radical and 3 to 20 glycol ether groups. These include ethoxylation products of alcohols, vicinal diols, amines, thioalcohols, fatty acid amides and fatty acids. Block polymers of ethylene oxide and propylene oxide, which are commercially available under the name Pluronic ^(R) (from BASF / Wyandotte), are also suitable. Alkylglucosides or alkylpolyglucosides and mixtures thereof with the ethoxylation products mentioned can also be used.

Preferred nonionic surfactants, which can be adsorbed on the granules and together with these are in the form of a free-flowing mixture, are derived from alcohols with 12 to 18 carbon atoms which are saturated or olefinically unsaturated, linear or methyl-branched in the 2-position (oxo radical ) could be. Their reaction products with ethylene oxide (EO) or propylene oxide (PO) are water-soluble or water-dispersible mixtures of compounds with different degrees of alkoxylation, the number of EO or PO groups given below corresponding to a statistical mean.

Examples of preferred ethoxylated fatty alcohols are C₁₂-C₁₈ coconut alcohols with 3 to 12 EO, C₁₆-C₁₈ tallow alcohol with 4 to 16 EO, oleyl alcohol with 4 to 12 EO and ethoxylation products of corresponding chain and EO distribution available from other native fatty alcohol mixtures. From the series of ethoxylated oxo alcohols, for example those of the composition C₁₂-C₁₅ with 5 to 10 EO and C₁₄-C₁₅ with 6 to 12 EO are suitable. Also suitable are alkoxylates containing EO groups and PO groups, for example C₁₂-C₁₈ alcohols of the formula R- (PO) _a - (EO) _b or R- (EO) _b - (PO) _c , wherein a Numbers from 1 to 3, b numbers from 5 to 20 and c numbers from 1 to 10, where b should be greater than c.

The liquid, optionally heated, additives, in particular the application of the nonionic surfactants and the melted paraffins, can be applied to the granules by mixing, preferably spraying, the carrier material advantageously being kept in motion by suitable mixing devices. It is particularly advantageous if the additives are applied to the still warm, preferably 40 to 80 ° C. warm granules immediately after the granules have been dried. Another aftercare of the granular adsorbates is not required. However, leaving the product to rest for several hours at high contents of applied liquid material can be expedient, since its diffusion into the interior of the grain takes some time.

After the application of the liquid additive, the grains can optionally be dusted with a finely divided powder as powdering agent or coated on the surface. As a result, the free-flowing properties of the granules can be improved and the bulk density can be increased slightly if the content of nonionic surfactants exceeds 15%. Suitable powdering agents have a grain size of 0.001 to at most 0.1 mm, preferably less than 0.05 mm and can be present in proportions of 0.03 to 3, preferably 0.05 to 2% by weight, based on that with additive loaded adsorbent. For example, finely powdered zeolites, silica airgel (Aerosil ^(R) ), colorless or colored pigments such as titanium dioxide are suitable. In general, however, such an aftertreatment is superfluous, especially since it does not improve the solution properties.

The detergent additives can be combined and mixed in a known manner with the granular or pulverulent detergent, for example a tower spray powder and its mixtures with other powder components, such as persalts, enzyme granules, bleach activators or defoamers. The high bulk density and the favorable flushing behavior of the additives according to the invention are transferred to these complex mixtures. In practice, the detergents generally contain 10 to 40% by weight of the additive according to the invention.

Examples

The granulation was carried out in a mixing granulator consisting of a horizontally arranged cylindrical mixer with a rotating shaft rotating in the central axis and equipped with mixing elements (ploughshare mixer, Lödige type) with a capacity of 5 l. The pulverulent constituents and the aqueous zeolite suspension were placed in the mixing granulator and processed to form a homogeneous mixture. After the mixing, which took about 10 seconds to 1 minute, the granulating liquid was sprayed in over the course of 1 to 5 minutes by means of nozzles and the mixture was granulated for a further 1 to 3 minutes with constant mixing. The granules leaving the mixer were dried in a fluidized bed with hot, flowing dry gases (100 ° C.). In all examples, the fine fraction (particle diameter smaller than 0.2 mm) was less than 5% and the coarse fraction (particle diameter larger than 1.6 mm) was less than 18%.

The zeolite powder mixture presented (Wessalith ^(R) CD; commercial product from Degussa / Germany) consisted of 71% by weight of NaA type zeolite (calculated as anhydrous active substance) and 5.4% by weight of sodium polyacrylic acid (Degapas 4104 N ^(R) ; commercial product from Degussa / Germany), calculated as an anhydrous active substance, 3.0% by weight of sodium sulfate, 2.0% by weight of C₁₂-C₁₈ fatty alcohol, with 5 Ethylene oxide groups (EO) was ethoxylated, 0.4% by weight of sodium hydroxide and 18.2% by weight of water. The aqueous zeolite suspension was 47% by weight of zeolite of the NaA type (calculated as anhydrous active substance) and contained 1.3% by weight of tallow alcohol with 5 EO and 0.3% by weight of sodium hydroxide. The sodium salt of the acrylic acid-maleic acid copolymer used (Sokalan ^(R) CP5 from BASF / Germany) had a relative molecular weight of approximately 70,000 and was used as a 40% strength by weight solution.

Example 1:

70 parts by weight of the zeolite powder mixture were introduced and sprayed with 30 parts by weight of a granulating liquid consisting of 20% by weight of the zeolite suspension and 80% by weight of Sokalan CP5 solution. The granules obtained after drying contained 63.7% by weight of zeolite (calculated as anhydrous active substance) and 16.2% by weight of (co) polymeric carboxylates (sum of Sokalan CP5 and Degapas). The bulk weight was 850 g / l. The proportion of particles with a diameter> 1.6 mm (sieve analysis) was 15.8%, the proportion of particles with a diameter <0.2 mm was 4.3%.

Example 2:

70 parts by weight of the zeolite powder mixture were introduced and 30 parts by weight of a granulating liquid consisting of 19% by weight of the zeolite suspension, 76% by weight of the Sokalan CP5 solution and 5% by weight. C₁₂-C₁₈ fatty alcohol sprayed with 5 EO. The granules obtained after drying contained 62.8% by weight of zeolite (calculated as anhydrous active substance, 15.5% by weight of (co) polymeric carboxylates (sum of Sokalan CP5 and Degapas) and 3.5% by weight C₁₂-C₁₈ fatty alcohol with 5 EO. The bulk density was 842 g / l. The proportion of particles with a diameter> 1.6 mm was 11.8%, the proportion of particles with a diameter <0.2 mm was 4. 2%.

Example 3:

Example 2 was repeated with a granulating liquid containing 18% by weight of zeolite suspension, 72% by weight of Sokalan CP5 solution and 10% by weight of C₁₂-C₁₈ fatty alcohol with 5 EO. The granules obtained after drying contained 62.0% by weight of zeolite (calculated as anhydrous active substance), 14.7% by weight of (co) polymeric carboxylates (sum of Sokalan CP5 and Degapas) and 5.3% by weight. % C₁₂-C₁₈ fatty alcohol with 5 EO. The bulk weight was 859 g / l. The proportion of particles with a diameter> 1.6 was 13.7, the proportion of particles with a diameter <0.2 mm was 3.8%.

Example 4:

Example 2 was repeated with a granulating liquid containing 17% by weight of the zeolite suspension, 68% by weight of Sokalan CP5 solution and 15% by weight of C₁₂-C₁₈ fatty alcohol with 5 EO. The granules obtained after drying contained 61.2% by weight of zeolite (calculated as anhydrous active substance), 14.0% by weight of (co) polymeric carboxylates (sum of constituents as above) and 7.0% by weight C₁₂-C₁₈ fatty alcohol with 5 EO. The bulk weight was 908 g / l. The proportion of particles with a diameter> 1.6 mm was 12.9%, the proportion of particles with a diameter <0.2 was 2.3%.

Experiments which were carried out analogously to Examples 1 to 4, in which the amount of the zeolite powder mixture introduced were between 65 and 75% by weight and the amount of the granulating liquid was between 25 and 35% by weight, in each case based on the moist granules , were varied, gave analogous results. Analogous results were also obtained in experiments with Wessalith CS ^(R) (commercial product from Degussa) as a zeolite powder mixture and a granulating liquid which, as nonionic surfactants, contains C₁₂-C₁₄ fatty alcohol with 3 EO or a mixture of C₁₂-C₁₄ fatty alcohol with 3 EO and C₁₂-C₁₈ fatty alcohol with 5 EO or an approximately 50% by weight aqueous C₁₂-C₁ Alkyl alkyl glucoside paste with a degree of oligomerization of 1.38.

Claims (9)

1. A process for the production of granules of zeolite and sodium or potassium salts of polymeric or copolymeric carboxylic acids, granulation being carried out in the presence of a granulation liquid and the granules obtained being dried until free-flowing granules with an apparent density of 750 to 1,000 g/l are obtained, characterized in that part of the zeolite is initially introduced in spray-dried form, at least 90% of the zeolite particles having a diameter of 50 to 700 »m, and the granulation liquid contains a mixture of water, zeolite and (co)polymeric carboxylates.
2. A process as claimed in claim 1, characterized in that at least 90% of the spray-dried zeolite initially introduced consists of particles between 100 and 600 »m in size.
3. A process as claimed in claim 1 or 2, characterized in that the granulation liquid contains 10 to 50% by weight and preferably 15 to 30% by weight of a 45 to 55% by weight aqueous zeolite suspension, which contains 1.5 to 3% by weight, based on the suspension, of stabilizers, and 10 to 40% by weight of (co)polymeric carboxylates, the water content of the granulation liquid being 40 to 80% by weight.
4. A process as claimed in claim 3, characterized in that the granulation liquid contains 5 to 12% by weight and preferably 6 to 10% by weight of zeolite (expressed as water-free active substance), 15 to 35% by weight and preferably 20 to 32% by weight of (co)polymeric carboxylate, 2 to 20% by weight of anionic and/or nonionic surfactants, preferably 5 to 15% by weight of nonionic surfactants, and 45 to 75% by weight and preferably 45 to 60% by weight of water.
5. A process as claimed in any of claims 1 to 4, characterized in that granulation liquid is added to 100 parts by weight of the zeolite powder mixture initially introduced or to a homogeneous mixture of zeolite and salts of the polymeric or copolymeric carboxylic acids optionally introduced in powder form in such a quantity that 15 to 45 parts by weight, preferably 20 to 40 parts by weight and more preferably 20 to 32 parts by weight, based on the moist granules, of liquid components are present.
6. A process as claimed in any of claims 1 to 5, characterized in that the granulation liquid is sprayed through nozzles onto the moving mixture.
7. A process as claimed in claim 6, characterized in that a mixture of all the constituents of the granulation liquid is sprayed or individual components are successively sprayed.
8. A process as claimed in any of claims 1 to 7, characterized in that dried granules are obtained which contain 55 to 95% by weight and preferably 60 to 92% by weight of water-containing zeolite and 2 to 20% by weight and preferably 10 to 17% by weight of sodium salts of polymeric or copolymeric carboxylic acids, the granules having an apparent density of 780 to 950 g/l and a very uniform grain size distribution in which the content of particles smaller than 0.2 mm is less than 5% and the content of particles larger than 1.6 mm is no more than 20% and preferably no more than 15%.
9. A process as claimed in any of claims 1 to 8, characterized in that the granules obtained are mixed with up to 20% by weight, based on the adsorbate, of at least one liquid detergent ingredient, preferably with liquid nonionic surfactant or foam inhibitor, more particularly a paraffin foam inhibitor.