EP0870007A1

EP0870007A1 - Enzyme granulate containing anti-corrosion agents for silver

Info

Publication number: EP0870007A1
Application number: EP96920771A
Authority: EP
Inventors: Kathleen Paatz; Wilfried Rähse; Werner Pichler; Jürgen Härer
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 1995-06-12
Filing date: 1996-06-03
Publication date: 1998-10-14
Also published as: DE19521371A1; WO1996041860A1

Abstract

The aim is to develop a process by means for producing in the simplest possible way an enzyme-containing granulate suitable for incorporation in particulate cleaning agents which also contains anti-corrosion agents for silver, e.g. in the form of certain organic redox substances, in which said components, especially the enzyme, have a long shelf life. This has essentially been achieved by the preparation of a granulate containing an intimate mixture of the enzyme, an inorganic and/or organic vehicle therefor, and a silver corrosion inhibitor and possibly granulation auxiliaries. The enzyme granulates may be used to produce solid, especially particulate cleaning agents.

Description

"Enzyme Granules Containing Silver Corrosion Protection Agents"

The invention relates to an enzyme granulate which contains a silver corrosion inhibitor, a process for its production and the use of the granulate in solid cleaning agents, in particular for machine dishwashing.

Enzymes, especially proteases, are used extensively in detergents, washing aids and cleaning agents. The enzymes are usually not used as concentrates, but in mixtures with a dilution and carrier material. If such enzyme preparations are admixed with conventional detergents or cleaning agents, a considerable reduction in the enzyme activity can occur during storage, especially if bleach-active compounds are present. The application of the enzymes to carrier salts with simultaneous granulation according to German Offenlegungsschrift DT 16 17 190 or by sticking with nonionic surfactants according to German Offenlegungsschrift DT 16 17 188 or aqueous solutions of cellulose ethers according to German Offenlegungsschrift DT 17 67 568 does not lead to one significant improvement in storage stability, since the sensitive enzymes in such mixtures are generally on the surface of the carrier substance. The storage stability of the enzymes can be significantly increased if the enzymes are encased or embedded in the carrier material and then converted into the desired particle shape by extrusion, pressing and marumerization, as described, for example, in German patent DE 16 17 232, German Offenlegungsschrift DT 20 32 768, and the German interpretations DE 21 37 042 and DE 21 37 043. However, such enzyme preparations only have poor solubility properties. The undissolved particles can get caught in the material to be cleaned and contaminate it, or they can be discharged into the waste water unused. Embedding agents known from German patent specification DT 18 03 099, which consist of a mixture of solid acids or acidic salts and carbonates or bicarbonates and which disintegrate when water is added, improve the solvency, but are themselves very sensitive to moisture and therefore require additional protective measures.

From the European patent EP 168 526 enzyme granules are known which contain starch which swells in water, zeolite and water-soluble granulation aid. In This document proposes a production process for such formulations, which essentially consists in concentrating a fermenter solution freed from insoluble constituents, adding the additives mentioned, granulating the resulting mixture and, if appropriate, coating the granules with film-forming polymers and dyes. The process with the additive mixture proposed there is advantageously carried out with fermentation solutions which have been concentrated to a relatively high dry matter content, for example 55% by weight. In addition, the granules produced in this way have such a high rate of dissolution or disintegration under operating conditions that the granules disintegrate relatively quickly even during storage and the enzymes are deactivated.

From international patent application WO 92/11347, enzyme granules for use in granular detergents and cleaning agents are known which contain 2% by weight to 20% by weight of enzyme, 10% by weight to 50% by weight of swellable starch, 5% by weight .-% to 50 wt .-% water-soluble organic polymer as Granuherhilfsxnittel, 10 wt .-% to 35 wt .-% cereal and 3 wt .-% to 12 wt .-% water. Such an additive mixture enables enzyme processing without major loss of activity, and the storage stability of the enzymes in the granules is also satisfactory.

A further problem, particularly in the case of cleaning agents for machine dishwashing, is the need to incorporate corrosion inhibitors for silverware into such agents, particularly if the agents contain the bleaching or oxidizing agents based on oxygen which have been customary in recent times. Silver can react when cleaning with sulfur-containing substances that are dissolved or dispersed in the rinsing water, because when cleaning dishes in household dishwashers, food residues and thus, among other things, mustard, peas, egg and other sulfur-containing compounds such as mercaptoamino acids are introduced into the washing liquor . The much higher temperatures during machine rinsing and the longer contact times with the sulfur-containing food residues also favor the tarnishing of silver compared to manual rinsing. Due to the intensive cleaning process in the dishwashing The silver surface is also completely degreased, making it more sensitive to chemical influences.

The problem of tarnishing silver becomes particularly acute when, as an alternative to the sulfur-containing substances, oxidatively "defusing" active chlorine compounds, active oxygen compounds, such as sodium perborate or sodium percarbonate, are used which remove bleachable stains, such as tea stains / tea deposits, coffee residues, dyes Vegetables, remains of lipstick and the like serve.

Such active oxygen bleaching agents are used, generally together with bleach activators, especially in modern, low-alkaline machine dishwashing detergents of the new generation of cleaners. These agents generally consist of the following functional components: builder component (complexing agent dispersant), alkali carrier, bleaching system (combination of bleaching agent and bleach activator), enzyme and surfactant. Under the purging conditions that occur when such compositions are used, not only sulfidic deposits are formed in the presence of silver, but also oxidic deposits on the silver surfaces as a result of the oxidizing attack ^{* of} the intermediately formed peroxides or of the active oxygen.

The avoidance of silver corrosion, that is, the formation of sulfidic, oxidic or chloride deposits on silver is the subject of numerous publications. From the British patent GB 1 131 738, alkaline dishwashing detergents are known which contain benzotriazoles as a corrosion inhibitor for silver. US Pat. No. 3,549,539 describes strongly alkaline, machine-applicable dishwashing detergents which can contain, inter alia, perborate with an organic bleach activator as the oxidizing agent. Additions of benzotriazole and iron (III) chloride are also recommended as anti-tarnish agents. European patent specifications EP 135 226 and EP 135 227 describe weakly alkaline machine dishwashing detergents containing peroxy compounds and activators, which may contain benzotriazoles and fatty acids as silver preservatives. Finally, it is known from German published patent application DE 41 28 672 that peroxy compounds, which are activated by the addition of known organic bleach activators, prevent the tarnishing of silver parts in strongly alkaline cleaning agents. German patent applications DE 43 25 922 and DE 43 15 397 describe the use of titanium, zirconium, hafnium, vanadium, cobalt or cerium salts and / or complexes in which the metals in one of the oxidation stages π, HL IV, V or VI are present, or of manganese (II) salts or complexes to prevent silver corrosion. The international patent application WO 94/19445 describes the use of certain manganese (iπ) or manganese (TV) complexes as silver corrosion inhibitors in mechanical dishwashing detergents. International patent application WO 94/07981 discloses the use of cysteine as a silver protection agent. German patent application 195 18 693.1 describes the supercorrosion-inhibiting action of cystine, alone or in particular in combination with isocyanuric acid.

Even if the cleaning agents mentioned for dishes are of relatively little complexity, efforts are nevertheless made to use components in their manufacture which contain more than one of the active ingredients listed above (builder, alkali carrier, bleaching system, enzyme, surfactant, silver corrosion inhibitor).

The unpublished German patent application DE 43 44 215 relates to enzyme granules suitable for incorporation into particulate cleaning agents in particular, containing enzyme and inorganic and / or organic carrier material in the core and optionally granulating aids onto which a uniform coating layer has been applied, which in particular applies a coating layer contains inorganic silver corrosion inhibitor. These enzyme granules can be produced in particular by applying an aqueous solution or dispersion which contains the silver corrosion inhibitor to an enzyme-containing core. Such a manufacturing process creates difficulties in the processing of water-insoluble or sparingly water-soluble silver corrosion inhibitors. In addition, additional energy is required for the evaporation of the water applied with the silver corrosion inhibitor.

It was therefore the task to develop a process which is able to produce, in the simplest possible way, an enzyme-containing granulate which additionally contains silver Corrosion protection agent, for example in the form of certain organic substances, in which the components mentioned, in particular the enzyme, are stable in storage.

The word "corrosion" is to be interpreted in its broadest meaning in chemistry, in particular "corrosion" here should stand for any visually just recognizable change in a metal surface, here silver, be it for example a selective discoloration or be it for example large start-up.

According to the invention, this object is achieved by enzyme granulate containing silver corrosion inhibitor which is suitable for incorporation into particulate cleaning agents and which contains enzyme, inorganic and / or organic carrier material for the enzyme and silver corrosion inhibitor and optionally granulation aids in an intimate, so to say homogeneous mixture.

The organic silver corrosion inhibitors include compounds with a trivalent N atom, such as pyrazole, thionalide, morpholine, melamine, cysteine, 2-mercaptobenzodiazole, distearylamine, isocyanuric acid, bezotriazole, aminotriazole, aminotetrazole, indazole and imidazole and its derivatives, for example organic benzimidazole Disulfides, for example cystine, and di- and trihydric phenols and their derivatives, for example hydroquinone, pyrocatechol, phloroglucinol, gallic acid, hydroxyhydroquinone and pyrogallol.

Examples of inorganic silver corrosion inhibitors are manganese, titanium, zirconium, hafnium, vanadium, cobalt or cerium salts and / or complexes in which the metals mentioned are present in one of the oxidation states II, HI, IV, V or VI. The counterions suitable for salt formation include all customary single, double or triple negatively charged inorganic anions, for example oxide, sulfate, nitrate, fluoride, but also organic anions such as stearate. For the purposes of the invention, metal complexes are compounds which consist of a central atom and one or more ligands and, if appropriate, additionally one or more of the above-mentioned anions. The central atom is one of the metals mentioned above in one of the oxidation states mentioned above. fen. The ligands are neutral molecules or anions, which can be monodentate or multidentate; the term “ligand” in the sense of the invention is explained in more detail, for example, in “Römpp Chemie Lexikon, Georg Thieme Verlag Stuttgart / New York, 9th edition, 1990, page 2507”. If the charge of the central atom and the charge of the ligand (s) do not add up to zero in a metal complex, then depending on whether there is a cationic or an anionic excess charge, either one or more of the abovementioned anions or one or more cations, for example sodium, potassium or ammonium ions, for charge balancing. Preferred metal salts or metal complexes are MnSO ₄ , V ₂ O ₅ , V ₂ O ₄ , VO ₂ , TiOSO ₄ , K ₂ TiF ₆ , K ₂ ZrF ₆ , CoSO ₄ , Co (NO ₃ ) ₂ , Ce (NO ₃ ) ₃ as well as their mixtures. These salts or complexes are commercially available substances that can generally be used for the purpose of protecting against silver corrosion without prior cleaning. For example, the oxidic mixture of tetravalent and pentavalent vanadium (V ₂ O ₅ , VO ₂ , V ₂ O ₄ ) known from SO ₃ production (contact process) is suitable, as is that by diluting a Ti (SO) ₂ - Solution with titanyl sulfate TiOSO ₄ .

In the finished enzyme granulate, 0.5% by weight to 40% by weight, in particular 1% by weight to 30% by weight and particularly preferably 2.5% by weight to 25% by weight, is preferably enzymatic Protein, 30% by weight to 95% by weight, in particular 40% by weight to 80% by weight of carrier material for the enzyme, optionally 3% by weight to 12% by weight of water and 0.5 % By weight to 50% by weight, in particular 5% by weight to 30% by weight, of silver corrosion inhibitor.

Enzymes primarily include the proteases, lipases, cutinases, amylases, pullulanases, hemicellulases, cellulases, oxidases and / or peroxidases obtained from microorganisms, such as bacteria or fungi, proteases produced by Bacillus species and their mixtures with amylases are preferred. They are obtained in a known manner by fermentation processes from suitable microorganisms, which are described, for example, in German patent applications DE 1940488, DE 2044 161, DE 22 01 803 and DE 21 21 397, US Pat. Nos. 3,632,957 and 4264 738 and European patent application EP 006638. The method according to the invention for the formulation of very active proteases, which are known, for example, from international patent application WO 91/02792 or US Pat. No. 5,340,735, are used because their storage-stable incorporation into detergents and cleaning agents often causes problems. If the enzyme granulate according to the invention is a protease-containing formulation, the protease activity is preferably 50,000 protease units (PE, determined by the method described in Tenside 7 (1970), 125) to 350,000 PE, in particular 100,000 PE up to 300,000 PE, per gram of enzyme granulate.

The particularly preferred enzyme granules according to the invention include those in which the enzyme protease and the silver corrosion inhibitor is MnSO, or in which the enzyme protease and the silver corrosion inhibitor is cystine, or in which the enzyme is amylase and the silver corrosion inhibitor cystine.

In principle, all organic or inorganic powdery substances which do not destroy or deactivate the enzymes to be granulated, or tolerably little, and which are stable under granulation conditions, can be used as carrier materials for the enzyme. Such substances include, for example, starch, cereal flour, cellulose powder, alkali alumosilicate, in particular zeolite, layered silicate, for example bentonite or smectite, and water-soluble inorganic or organic salts, for example alkali metal chloride, alkali metal sulfate, alkali metal carbonate or alkali metal acetate, sodium or potassium being the preferred alkali metals. A carrier material mixture of starch which is swellable in water, cereal flour and optionally cellulose powder and alkali carbonate is preferably used.

The starch which is swellable in water is preferably corn starch, rice starch, potato starch or mixtures thereof, the use of corn starch being particularly preferred. Swellable starch is contained in the enzyme granules according to the invention preferably in amounts of from 20% by weight to 50% by weight, in particular from 25% by weight to 45% by weight. The sum of the amounts of the swellable starch and the flour is preferably not more than 80% by weight, in particular 32% by weight to 65% by weight. The cereal flour is in particular a product which can be produced from wheat, rye, barley or oats or a mixture of these flours, wholemeal flours being preferred. A wholemeal flour is understood to mean a flour which has not been fully ground and which has been produced from whole, unpeeled grains or at least predominantly consists of such a product, the rest consisting of fully ground flour or starch. Commercial wheat flour qualities such as type 450 or type 550 are preferably used. It is also possible to use flour products from the cereals leading to the aforementioned swellable starches, provided that care is taken to ensure that the flours have been produced from the whole grains. The flour component of the additive mixture is known to achieve a substantial odor reduction in the enzyme preparation, which far exceeds the reduction in odor by incorporating the same amounts of corresponding starch types. Such cereal flour is contained in the enzyme granules according to the invention preferably in amounts from 5% by weight to 35% by weight, in particular from 10% by weight to 25% by weight.

The enzyme granules according to the invention preferably contain, as a further component of the carrier material, 1% by weight to 50% by weight, preferably 5% by weight to 25% by weight, based on the total granulate, of a granulation aid system, the alkali carboxymethyl cellulose contains with degrees of substitution from 0.5 to 1 and polyethylene glycol and / or alkyl polyethoxylate. This granulation aid system preferably contains, based in each case on finished enzyme granules, 0.5% by weight to 5% by weight of alkali carboxymethyl cellulose with degrees of substitution from 0.5 to 1 and up to 3% by weight of polyethylene glycol and / or Contain alkyl polyethoxylate, it being particularly preferred if at least 0.5% by weight, in particular 0.8% by weight to 2% by weight, of polyethylene glycol with an average molecular weight below 1000 and / or alkyl polyethoxylate with at least 30 ethoxy groups is present, if more than 2% by weight of alkali carboxymethyl cellulose is contained.

If necessary, additional cellulose or starch ethers, such as carboxymethyl starch, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and corresponding cellulose mixed ethers, gelatin, casein, tragacanth, maltodextrose, sucrose, invert sugar, glucose syrup or others can also be used as additional constituents of the granulation aid system Water-soluble or readily dispersible oligomers or polymers of natural or synthetic origin can be used. Usable synthetic water-soluble polymers are polyacrylates, polymethacrylates, copolymers of acrylic acid with maleic acid or compounds containing vinyl groups, furthermore polyvinyl alcohol, partially saponified polyvinyl acetate and polyvinyl pyrrolidone. Insofar as the aforementioned compounds are those with free carboxyl groups, they are normally in the form of their alkali metal salts, in particular their sodium salts. Such additional granulation aids can be contained in the enzyme granules according to the invention in amounts of up to 10% by weight, in particular from 0.5% by weight to 8% by weight. Higher molecular weight polyethylene glycols, that is to say those with an average molecular weight of more than 1000, can be used as synthetic water-soluble polymers with a dust-binding effect, but it is precisely the higher molecular weight polyethylene glycols which cause an undesirable increase in the granule dissolution time required, so that these substances can be used in the invention Enzyme granules are preferably completely absent.

In a preferred embodiment, the enzyme granules have a uniform outer coating layer. A coating system which contains 10% by weight to 30% by weight of finely divided inorganic pigment, 45% by weight to 80% by weight of an alcohol or alcohol mixture with a melting point in the range of 35 ° C. is particularly suitable for the coating layer up to 75 ° C, up to 15 wt .-% emulsifier for the alcohol, up to 5 wt .-% dispersant for the pigment and up to 5 wt .-% water.

The alcohol component of the coating system is preferably a primary linear alcohol with 14 to 22 carbon atoms or a mixture of these. The alcohols mentioned include in particular myristyl alcohol, cetyl alcohol, stearyl alcohol, arachidyl alcohol, behenyl alcohol and mono- to tri-unsaturated alcohols of appropriate chain length, it being essential that the alcohol component of the coating system mentioned has a melting point in the range from 35 ° C. to 75 ° C, in particular from 50 ° C to 60 ° C, which is to be understood here as the temperature at which 100% of the alcohol component is present in liquid form when heated. When alcohol mixtures are used, it is also possible to use those which contain small proportions, normally below 15% by weight, based on the alcohol mixture, of proportions which are liquid at room temperature. hold as long as the entire alcohol mixture appears solid at room temperature and has a solidification point in the temperature range mentioned above. The solidification point is the temperature at which solidification occurs when the material which has been heated to a temperature above the melting point cools down. It can be determined with the help of a rotating thermometer according to the procedure of DIN ISO 2207.

Suitable emulsifiers for the alcohol component are substances which are able to emulsify the alcohol component in water so that a mixture which can be sprayed at temperatures of up to 95 ° C. is obtained and / or which allow the coating system to be as homogeneous as possible to transfer meltable sprayable at temperatures up to 120 ° C. In this context, it can serve as a point of reference that liquids with viscosities of up to about 10,000 mPa.s can generally be sprayed without any problems at the temperatures mentioned by means of devices provided for this purpose and applied to enzyme granules. The emulsifiers for the alcohol component of the coating system include, for example, the ethoxylation products of the alcohols mentioned, their reaction products with an average of 25 to 80, in particular 30 to 45, molar equivalents of ethylene oxide being preferred. If the coating system is applied to the enzyme granulate as an aqueous dispersion, preferred among the compounds mentioned are those with degrees of ethoxylation of 25 to 50, that is to say reaction products with 25 to 50 molar equivalents of ethylene oxide. Alternatively or in addition to the alcohol ethoxylates, ethoxylated fatty acids, the degree of ethoxylation preferably being 3 to 9, ethoxylated fatty acid amides, the degree of ethoxylation preferably being 4 to 11, and / or ethoxylation products of hydroxy fatty acid esters having 1 to 6 C- Atoms in the alcohol part of the ester, for example ricinoleic acid glyceride, where the degree of ethoxylation is preferably 5 to 80, in particular 20 to 40, can be used as the emulsifier component in the coating system. The fatty acid component of the substances mentioned preferably has 12 to 22 carbon atoms. If desired, the ethoxy groups in the emulsifiers mentioned can be at least partially replaced by propoxy groups.

The inorganic pigments with which possible disruptive coloring of the enzyme granulate can be covered include, for example, calcium carbonate, Titanium dioxide, which can be in rutile or anatase crystal modification, zinc oxide, zinc sulfide, lead white (basic lead carbonate), barium sulfate, aluminum hydroxide, anti-monoxide, lithopone (zinc sulfide-barium sulfate), kaolin, chalk and / or mica. These are in such a finely divided form that they can be dispersed in a melt of the organic constituents of the coating system or in water. The average particle size of such pigments is usually in the range from 0.004 μm to 50 μm. In particular if the pigment or the entire coating system is to be used in the form of an aqueous dispersion, it is preferred that this dispersion contains dispersing agents for the pigment and / or, as described below, the additional silver corrosion inhibitor which is optionally present in the coating system. Such dispersants can be inorganic, for example aluminum oxide or silicon oxide, which can also serve as pigments, or organic, for example diethylene glycol or dipropylene glycol. Use with dispersants of surface-modified pigments is also possible. Titanium dioxide pigment which is surface-modified with Al, Si, Zr or polyol compounds is preferred, in particular in rutile form, as is sold, for example, under the trade names Kronos® 2132 (Kronos-Titan) or Hombitan® R 522 (Sachtleben Chemie GmbH) , used. The Tiona® RLL, AG and VC types from Solvay and the Bayertitan® RD, R-KB and AZ types from Bayer AG can also be used.

Further silver corrosion inhibitor can also be contained in the uniform coating layer, as described in DE 43 44 215. In this case, the coating system preferably has a content of at least 25% by weight of a silver corrosion inhibitor, in particular a silver corrosion inhibitor which is not identical to the silver corrosion inhibitor contained in the enzyme core, up to 30% by weight, in particular 5% by weight to 25% by weight. % finely divided inorganic pigment, 5% by weight to 75% by weight at room temperature solid alcohol with a melting point in the range from 35 ° C. to 75 ° C., up to 10% by weight, in particular 1% by weight up to 5% by weight emulsifier for the alcohol, up to 5% by weight, in particular 0.2% by weight to 3% by weight of dispersant for the inorganic pigment or the silver corrosion inhibitor and up to 7% by weight of water on. For reasons of higher enzyme stability, the enzyme granules containing silver corrosion inhibitor are preferably produced, at least in part, based on the processes of international patent application WO 92/11347 comprising an extrusion step or German patent application DE 43 10 506 using swellable starch, water-soluble organic polymer and cereal flour .

Another object of the invention thus relates to a method for producing an enzyme granulate containing silver corrosion inhibitor suitable for incorporation into particulate cleaning agents by mixing an aqueous liquid containing the enzyme, which liquid can optionally be a fermentation broth freed from insoluble constituents and concentrated. with inorganic and / or organic carrier material and the silver corrosion inhibitor, subsequent extrusion of the mixture obtained in this way through a perforated plate with subsequent cutting device, optionally spheronization of the extrudate in a rounding device and drying, and, if appropriate, application of a dye and / or pigment-containing coating, if desired train Such a method has the advantage over known methods that it also makes it possible to process silver corrosion inhibitors which are insoluble or only slightly water-soluble.

The enzyme granules according to the invention are preferably prepared from fermentation broths which are freed of insoluble accompanying substances, for example by microfiltration. The microfiltration is preferably carried out as a cross-flow microfiltration using porous tubes with micropores larger than 0.1 μm, flow rates of the concentrate solution of more than 2 m / s and a pressure difference to the permeate side of less than 5 bar, as for example in the European patent application EP 200 032. The microfiltration permeate is then concentrated, preferably by ultrafiltration, if appropriate with subsequent vacuum evaporation. The concentration can, as described in international patent application WO 92/11347, be carried out in such a way that only relatively low dry matter contents of preferably 5% by weight to 50% by weight, in particular 10% by weight up to 40% by weight. The concentrate is expediently prepared beforehand in a dry, powdery to granular mixture of the additives described above. Impact substances, including the silver corrosion inhibitor, metered in and mixed in. The water content of the mixture should be selected so that it can be converted into granular particles which do not stick at room temperature when processed with stirring and striking tools and plastically deformed and extruded when using higher pressures. The free-flowing premix is, in principle, subsequently processed in a kneader and a connected extruder to form a plastic mass which is as homogeneous as possible Can heat 55 ° C. The material leaving the extruder is passed through a perforated disk with a subsequent knock-off knife and is thereby reduced to cylindrical particles of a defined size. The diameter of the bores in the perforated disk is expediently 0.7 mm to 1.6 mm, preferably 0.8 mm to 1.4 mm. The particles in this form can then be dried and coated with a coating system. However, it has proven to be advantageous to spheronize the cylindrical particles leaving the extruder and chopper before coating, that is to round them off and deburr them in suitable devices. For this purpose, a device is used which consists of a cylindrical container with stationary, fixed side walls and a friction plate rotatably mounted on the bottom. Devices of this type are widely used in technology under the Marumerizer® product name and are described, for example, in the German specifications DE 21 37 042 and DE 21 37 043. Any dusty particles with a grain size of less than 0.1 mm, in particular less than 0.4 mm, and any coarse particles with a grain size of more than 2 mm, in particular more than 1.6 mm, can then be removed by sieving or air separation and, if necessary, in the Manufacturing process can be traced. After spheronization, the beads can be added continuously or in batches, preferably using a fluidized bed drying unit, at supply air temperatures of preferably 35 ° C. to 50 ° C. and in particular at a product temperature of not more than 42 ° C. up to the desired residual moisture content of, for example, 4% by weight. % to 10% by weight, in particular 5% by weight to 8% by weight, based on the total granulate, are dried. After or preferably during drying, the coating system, which optionally contains additional silver corrosion inhibitor, can be applied as an outer covering. In one embodiment of the production process according to the invention, the coating system is in the form of an aqueous solution or dispersion which preferably contains 30% by weight to 65% by weight of water and 35% by weight to 70% by weight of the coating system, in particular 1 % By weight to 2.5% by weight, based on the entire coating system, of dispersant for the pigment and / or the silver corrosion inhibitor, is introduced into the fluidized bed of enzyme extrudate. The water supplied via the aqueous dispersion is removed during the drying which is carried out simultaneously or is subsequently necessary again. In a further embodiment of the production method according to the invention, the coating system, optionally with cooling, is applied to the enzyme-containing extrudate as a heated liquid at a temperature of 5 ° C. to 45 ° C. above the melting point of the alcohol component. In addition, a combination of these procedures, consisting in applying part of the coating system in the form of an aqueous solution or dispersion and a second part in the form of a melt, is possible. Preferably, based on the finished granulate, 10% by weight to 50% by weight of the coating system is applied to the enzyme-containing extrudate as an outer coating layer.

A further embodiment of this method comprises the production of enzyme granules which contain two or more different enzymes. The procedure is preferably such that an enzyme core containing super-anticorrosive agents, prepared as described by extrusion, is mixed with a second enzyme which has been made up in particulate form and, if appropriate, further enzymes made up in particulate form, under agglomeration conditions, a binder optionally being used, and the coating material is then used or applies simultaneously, the average particle size of the extrudate core containing the first enzyme preferably being 1.1 to 3 times, in particular 1.3 to 2 times that of the second or further enzyme-shaped enzyme. This variant is based on the production method for multi-enzyme granules disclosed in German patent application DE 43 29463. The enzyme in the extrudate core is preferably Protease and in the enzyme contained in the separately produced, smaller particles which agglomerate to the extrudate or in the enzymes, if several different smaller particles are used, to amylase, pullulanase, lipase, cutinase, hemicellulase, cellulase, peroxidase and / or Oxidase. For use in dishwashing detergents, multi-enzyme granules containing silver corrosion inhibitor, which contain protease in the extrudate core and amylase and / or lipase in the separately produced, smaller particles, are particularly preferred.

The enzyme preparation obtained by the process according to the invention consists of largely rounded, uniformly coated and dust-free particles which generally have a bulk density of approximately 500 to 900 grams per liter, in particular 650 to 880 grams per liter. The granules according to the invention are notable for very high storage stability, in particular at temperatures above room temperature and high atmospheric humidity, and good dissolution behavior in the detergent liquor.

The enzyme granulate according to the invention or produced by the method according to the invention is preferably used for the production of solid, in particular particulate cleaning agents which can be obtained by simply mixing the enzyme granules with other powder components customary in such agents. For incorporation into particulate agents, the enzyme granules preferably have average grain sizes in the range from 0.8 mm to 1.6 mm. The granules according to the invention preferably contain less than 2% by weight, in particular at most 1.4% by weight, of particles with particle sizes outside the range from 0.4 mm to 1.6 mm.

Since the silver corrosion inhibitors, as stated above, are particularly suitable for preventing silver corrosion when they are contained in lower-alkaline cleaners for machine cleaning of dishes, a further subject of the invention is a lower-alkaline agent for machine cleaning of dishes whose 1% by weight solution has a pH of 8 to 11.5, preferably 9 to 10.5, containing enzyme, silver corrosion inhibitor, 15% by weight to 60% by weight, preferably 30% by weight to 50% by weight of water-soluble builder component, 5% by weight % up to 25% by weight, preferably 10% by weight to 15% by weight of oxygen-based bleach, 1% by weight to 10% by weight, preferably 2% by weight to 6% by weight of bleach activator, in each case based on the total agent, which is characterized in that it contains 0.1% by weight to 10% by weight, in particular 0.5% by weight to 5% by weight, of enzyme granules, which enzyme, inorganic and / or contains organic carrier material for the enzyme and silver corrosion protection agent and optionally granulation aids in intimate mixture. Also here are organic disulfides, dihydric phenols, trihydric phenols, manganese, titanium, zirconium, hafiiium, vanadium, cobalt or cerium salts and / or - complexes in which the metals mentioned are in one of the oxidation states π, IQ, IV, V or VI are present, preferred silver corrosion inhibitors.

In principle, all builders typically used in machine dishwashing detergents, for example polymeric alkali metal phosphates, which can be present in the form of their alkaline neutral or acidic sodium or potassium salts, are suitable as water-soluble builder components in such low-alkaline cleaning agents. Examples of this are tetrasodium diphosphate, disodium dihydrogen diphosphate, pentasodium tri-phosphate, so-called sodium hexametaphosphate and the corresponding potassium salts or mixtures of sodium and potassium salts. Their amounts can range up to about 35% by weight, based on the total agent; however, the agents according to the invention are preferably free of such phosphates. Other possible water-soluble builder components are, for example, organic polymers of native or synthetic origin, especially polycarboxylates, which act as co-builders, in particular in hard water regions. For example, polyacrylic acids and copolymers of maleic anhydride and acrylic acid and the sodium salts of these polymer acids are suitable. Commercial products are, for example, Sokalan® CP 5 and PA 30 from BASF. Polymers of native origin that can be used as co-builders include, for example, oxidized starch, as known, for example, from international patent application WO 94/05762, and polyamino acids such as polyglutamic acid or polyaspartic acid. Other possible builder components are naturally occurring hydroxycarboxylic acids such as, for example, mono-, dihydroxysuccinic acid, α-hydroxypropionic acid and gluconic acid. The preferred builder components include the salts of the citro- Nenoic acid, especially sodium citrate. Anhydrous trisodium citrate and preferably trisodium citrate dihydrate are suitable as sodium citrate. Trisodium citrate dihydrate can be used as a fine or coarse crystalline powder. Depending on the pH finally set in the agents according to the invention, the acids corresponding to the co-builder salts mentioned can also be present.

Suitable oxygen-based bleaches are primarily sodium perborate mono- or tetrahydrate and / or sodium percarbonate. The use of sodium percarbonate has advantages, since this has a particularly favorable effect on the corrosion behavior on glasses. The oxygen-based bleach is therefore preferably a percarbonate salt, especially sodium percarbonate. Since bleaching agents based on oxygen generally only develop their full effect at elevated temperatures, so-called bleach activators are used to activate them at about 60 ° C. and below, that is to say the approximate temperatures of the cleaning process in the dishwasher. Pentaacetylglucose, l, 5-diacetyl-2,2-dioxo-hexahydro-l, 3,5-triazine (DADHT) and / or isatoic anhydride, for example, can be used as bleach activators, but preferably N, N, N ', tetraacetylethylenediamine (TAED). Alternatively, known peroxycarboxylic acids, for example dodecanediperic acid or phthalimidopercarboxylic acids, which can optionally be substituted on the aromatic, can also be present. In addition, the addition of small amounts of known bleach stabilizers such as, for example, phosphonates, borates or metaborates ^" and metasilicates and magnesium salts such as magnesium sulfate can also be useful.

The agents according to the invention preferably contain the alkali carriers, such as, for example, alkali silicates, alkali carbonates and / or alkali bicarbonates, contained in customary low-alkaline machine dishwashing detergents. The alkali carriers usually used include carbonates, hydrogen carbonates and alkali silicates with a SiO ₂ / M ₂ O (M = alkali atom) molar ratio of 1.5: 1 to 2.5: 1. Alkali silicates can be used in amounts of up to 30% by weight .-%, based on the total agent, may be included. The use of the highly alkaline metasilicates as alkali carriers is preferably avoided entirely. The alkali carrier system preferably used in the agents according to the invention is a mixture of carbonate and bicarbonate, preferably sodium carbonate and bicarbonate, which is contained in an amount of up to 60% by weight, preferably 10% by weight to 40% by weight. Depending on which pH value is ultimately desired, the ratio of carbonate and hydrogen carbonate used varies, but an excess of sodium hydrogen carbonate is usually used, so that the weight ratio between hydrogen carbonate and carbonate is generally 1: 1 to 15: 1 is.

In addition, the agents according to the invention can contain ready-made enzymes such as proteases, amylases, lipases and cellulases which are not in the form of the granules according to the invention, for example proteases such as BLAP®, Optiase®, Opticlean®, Maxacal®, Maxapem®, Esperase ® and / or Savinase®, amylases like Termamyl®, Amylase-LT® and / or Maxamyl®, lipases like Lipolase®, Lipomax®, Lumafast® and / or Lipozym®, cellulases like Celluzym® and / or KAC®.

If appropriate, surfactants, in particular low-foaming nonionic surfactants, can also be added to the agents according to the invention, which serve to better detach fatty food residues, as wetting agents and, if appropriate, as granulating aids in the course of the preparation of the cleaning agents. Their amount can be up to 5% by weight, preferably up to 2% by weight. Extremely low-foaming compounds are usually used in particular in cleaning agents for use in machine dishwashing processes. These preferably include C ₂ -C alkyl polyglycol-propylene glycol ether, each with up to 8 moles of ethylene oxide and propylene oxide units in the molecule. But you can also use other known low-foaming nonionic surfactants, such as Cπ-Cis-alkylpolyethylene glycol-polybutylene glycol ether, each with up to 8 moles of ethylene oxide and butylene oxide units in the molecule, end-capped alkylpolyalkylene glycol mixed ethers and the foaming but ecologically attractive Cg- C _H alkyl polyglucosides with a degree of polymerization of about 1 to 4 (eg APG® 225 and APG® 600 from Henkel) and / or C ₂ -C ₁₄ alkyl polyethyleneglycols with 3 to 8 ethylene oxide units in the molecule. Also suitable are surfactants from the family of glucamides, such as, for example, alkyl-N-methyl-glucamides, in which the alkyl part preferably comes from a fatty alcohol with the C chain length Cβ-Cu. It is sometimes advantageous if the surfactants described are used as mixtures den, for example the combination of alkyl polyglycoside with fatty alcohol ethoxylates or glucamide with alkyl polyglycosides.

If the cleaning agents foam too much during use, they can still contain up to 6% by weight, preferably about 0.5% by weight to 4% by weight, of a foam-suppressing compound, preferably from the group of silicone oils, mixtures of silicone oil and hydrophobicized silica, paraffins, paraffin-alcohol combinations, hydrophobicized silica, the bisfatty acid amides, and other other known commercially available defoamers. Other optional ingredients in the agents according to the invention are, for example, perfume oils.

The dishwashing detergents according to the invention are preferably in the form of powdery, granular or tablet-like preparations which, in a manner known per se, for example by mixing, granulating, roller compacting and / or by spray drying the thermally loadable components and admixing the more sensitive components, to which in particular the enzyme granulate according to the invention is to be expected, can be produced.

For the preparation of cleaning agents according to the invention in tablet form, the procedure is preferably such that all constituents are mixed with one another in a mixer and the mixture by means of conventional tablet presses, for example eccentric presses or rotary presses, with pressing pressures in the range from 200 ^• 10 ⁵ Pa to 1 500 ^• 10 ⁵ Pa pressed. In this way, break-resistant tablets are obtained which, under application conditions, dissolve sufficiently quickly and have a flexural strength of normally over 150 N. A tablet produced in this way preferably has a weight of 15 g to 40 g, in particular 20 g to 30 g, with a diameter from 35 mm to 40 mm.

Dishwashing detergents according to the invention in the form of non-dusting, storage-stable, free-flowing powders and / or granules with high bulk densities in the range from 800 to 1000 g / 1 can be carried out by adding the builder components with at least a proportion of liquid mixture components in a first process stage Increase in the bulk density of this premixed mixture and subsequently - if desired after an intermediate drying - the other constituents of the agent, including the enzyme granules containing silver corrosion inhibitor, combined with the premix obtained in this way.

The agents can be used both in household dishwashers and in commercial dishwashers. It is added by hand or using suitable dosing devices. The application concentrations in the cleaning liquor are generally about 1 to 8 g / 1, preferably 2 to 5 g / 1.

A machine wash program is generally supplemented and ended by a few intermediate rinse cycles with clear water and a rinse cycle with a customary rinse aid after the cleaning cycle. After drying, when using the agents according to the invention, not only are completely clean dishes which are impeccable from a hygienic point of view, but above all also bright silver cutlery items.

example

An aqueous protease concentrate obtained after fermentation, removal of the fermentation residues by decanting, microfiltration in an ultrafiltration system and further concentration by means of vacuum evaporation as described in international patent application WO 91/02792 was mixed with the additives listed in the table below in a laboratory mixer from Lödige® homogeneously mixed and converted into granules with the aid of an extruder with a cutting device.

Table 1: Amounts used [% by weight]

Protease concentrate 22

Polyethylene glycol ^* 3

Cellulose powder ^b) 6.5

Sucrose 3.5

Carboxymethyl cellulose 7

Wheat flour T 450 15

Corn starch 33

L-cystine ^c) 10

a) average molecular weight 400 b) Technocel® 30 c) supplier Freedom Chemical Diamalt GmbH

The hole diameter of the perforated plate of the extruder was 0.8 mm. The ratio of length to thickness of the granules was 1. After rounding and drying the granules in a fluidized bed dryer, the particles with particle sizes smaller than 0.4 mm and larger than 1.6 mm were sieved. The grain fraction between 0.4 mm and 1.6 mm was in a ball coater with Turbojet system from Hüttlin with a coating layer coated, a melt of 70% by weight technical stearyl alcohol, 6% by weight 40 times ethoxylated tallow fatty alcohol and 24% by weight titanium dioxide being used. The enzyme granulate containing silver protective agent obtained had a protease activity of 145,600 PE / g.

It was incorporated in an amount of 1.1% by weight in a machine dishwashing detergent according to German patent application 195 18 693.1, the 45% by weight trisodium citrate dihydrate, 32.15% by weight sodium hydrogen carbonate, 5% by weight sodium carbonate , 3% by weight nonionic surfactant, 1% by weight amylase granules, 12% by weight sodium percarbonate and 0.75% by weight isocyanuric acid, each based on the finished agent. The agent was tested as described in the aforementioned application and evaluated with regard to its silver protective effect. Like the agent in which the enzyme and cystine were not incorporated together in one grain, it achieved a rating of 1.0 (hardly discolored surface).

Claims

1. Enzyme granules containing silver corrosion inhibitor which are suitable for incorporation into particulate cleaning agents in particular, characterized in that they contain an enzyme, inorganic and / or organic carrier material for the enzyme and silver corrosion inhibitor and optionally granulation aids in intimate mixture.

2. Enzyme granules according to claim 1, characterized in that the Silberkorrosionin¬ inhibitor from the group comprising organic disulfides, dihydric phenols, trivalent phenols and manganese, titanium, zirconium, hafnium, vanadium, cobalt or cerium salts and / or complexes in which the metals mentioned are present in one of the oxidation states π, HI, IV, V or VI.

3. Enzyme granules according to claim 1 or 2, characterized in that the Silberkorro¬ sionsinhibitor cystine, hydroquinone, pyrocatechol, phloroglucin, gallic acid, hydroxyhydroquinone, pyrogallol, MnSO ₄ , V ₂ O ₅ , V ₂ O ₄ , VO ₂ , TiOSO ₄ , K _{2 is} TiF ₆ , K ₂ ZrF ₆ , CoSO ₄ , Co (NO ₃ ) ₂ and / or Ce (NO ₃ ) ₃ .

4. Enzyme granules according to one of claims 1 to 3, characterized in that it contains 0.5% by weight to 40% by weight, in particular 1% by weight to 30% by weight, of enzymatic protein, 30% by weight up to 95% by weight, in particular 40% by weight to 80% by weight, of carrier material for the enzyme, optionally 3% by weight to 12% by weight of water and 0.5% by weight to 50% by weight .-%, in particular 5 wt .-% to 30 wt .-% silver corrosion inhibitor contains.

5. Enzyme granules according to one of claims 1 to 4, characterized in that it has a uniform outer coating layer of a coating system which 10 wt .-% to 30 wt .-% of finely divided inorganic pigment, 45 wt .-% to 80 wt .-% % of an alcohol or alcohol mixture with a melting point in the range from 35 ° C. to 75 ° C., up to 15% by weight emulsifier for the alcohol, up to 5% by weight dispersant for the pigment and up to 5% by weight. -% contains water.

6. Enzyme granules according to one of claims 1 to 4, characterized in that it has a uniform outer coating layer of a coating system composed of at least 25% by weight of a silver corrosion inhibitor, in particular a silver corrosion inhibitor which is not identical to the silver corrosion inhibitor contained in the enzyme core, up to 30% by weight. %, in particular 5% by weight to 25% by weight of finely divided inorganic pigment, 5% by weight to 75% by weight of alcohol which is solid at room temperature and has a melting point in the range from 35 ° C. to 75 ° C., up to 10 % By weight, in particular 1% by weight to 5% by weight, of emulsifier for the alcohol, up to 5% by weight, in particular 0.2% by weight to 3% by weight of dispersant for the inorganic pigment ¬ as the silver corrosion inhibitor and up to 7 wt .-% water.

7. enzyme granules according to claim 5 or 6, characterized in that the alcohol in the coating layer is a primary linear alcohol having 14 to 22 carbon atoms or a mixture of these, and / or that the coating layer as an inorganic pigment titanium dioxide, zinc oxide, chalk and / or contains calcium carbonate.

8. Enzyme granules according to one of claims 1 to 7, characterized in that it contains protease, amylase, pullulanase, lipase, cutinase, cellulase, hemicellulase, oxidase and / or peroxidase.

9. enzyme granulate according to one of claims 1 to 8, characterized in that the enzyme protease and the silver corrosion inhibitor is MnSO ₄ .

10. Enzyme granules according to one of claims 1 to 8, characterized in that the enzyme protease and the silver corrosion inhibitor is cystine.

11. Enzyme granules according to one of claims 1 to 8, characterized in that the enzyme is amylase and the silver corrosion inhibitor is cystine

12. Enzyme granules according to one of claims 1 to 10, characterized in that it contains protease with an activity of 50,000 PE to 350,000 PE, in particular 100,000 PE to 300,000 PE, per gram of enzyme granules.

13. Process for the preparation of enzyme granules containing silver corrosion inhibitor by mixing an aqueous liquid containing the enzyme, which can optionally be a fermentation broth freed from insoluble constituents and concentrated, with inorganic and / or organic carrier material and the silver corrosion inhibitor, followed by extrusion the mixture thus obtained through a perforated plate with subsequent cutting device, optionally spheronization of the extrudate in a rounding device and drying, and optionally applying a coating optionally containing dye and / or pigment.

14. The method according to claim 13, characterized in that the silver corrosion inhibitor from the group comprising organic disulfides, dihydric phenols, trihydric phenols, manganese, titanium, zirconium, hafnium, vanadium, cobalt or cerium salts and / or complexes in which the metals mentioned are present in one of the oxidation states Q, QI, IV, V or VI.

15. The method according to claim 13 or 14, characterized in that the swellable carrier material for the enzyme cellulose, maltodextrose, sucrose, invert sugar, glucose or mixtures thereof, in particular a mixture of powdery cellulose and sucrose, is used, and starches as further carrier materials, Cereal flours, cellulose ethers, alkali alumosilicate, in particular zeolite, layered silicate, in particular bentonite or smectite, water-soluble inorganic or organic salts, in particular alkali metal chloride, alkali metal sulfate, alkali metal carbonate or alkali metal acetate, can be used.

16. The method according to claim 15, characterized in that the carrier material starch in amounts of 20 wt .-% to 80 wt .-%, in particular from 25 wt .-% to 75 wt .-%, and cereal flour in amounts of 5 wt % to 35% by weight, in particular from 10% by weight to 25% by weight, based in each case on the entire carrier material.

17. The method according to any one of claims 13 to 16, characterized in that the diameter of the holes in the perforated plate is 0.7 mm to 1.6 mm, in particular 0.8 mm to 1.4 mm.

18. The method according to any one of claims 13 to 17, characterized in that an enzyme core prepared by extrusion containing silver corrosion inhibitor is mixed with a particulate assembled second enzyme and optionally further particulate assembled enzymes under agglomeration conditions, the mean particle size of the extrudate core containing the first enzyme ins¬ especially 1.1 to 3 times that of the second or further particulate enzyme.

19. The method according to claim 18, characterized in that the enzyme in the extrudate core protease and the enzyme contained in the separately produced, smaller particles which agglomerate to the extrudate, is amylase, lipase, cellulase and / or Oxida¬ se.

20. Use of an enzyme granulate according to one of claims 1 to 12 or of an enzyme granulate produced by a method according to one of claims 13 to 19 for the production of solid, in particular particulate detergents.

21. Low-alkaline agent for machine cleaning of dishes, containing enzyme, silver corrosion inhibitor, 15% by weight to 60% by weight, in particular 30% by weight to 50% by weight of water-soluble builder component, 5% by weight to 25% by weight .-%, in particular 10 wt .-% to 15 wt .-% oxygen-based bleach, .1 wt .-% to 10 wt .-%, in particular 2 wt .-% to 6 wt .-% bleach activator, thereby gekenn¬ characterized that it contains 0.1 wt .-% to 10 wt .-%, in particular 0.5 wt .-% to 5 wt .-% enzyme granules, which enzyme, inorganic and / or organic carrier material for the Enzyme and silver corrosion inhibitor and optionally pelletizing agent in intimate mixture contains.