MXPA00002645A - Bleaching activators based on ammonium nitrile in the form of coated granules - Google Patents

Abstract

The invention concerns bleaching activators based on ammonium nitrile in the form of coated granules, obtained by coating granules based on ammonium nitrile with a water-soluble coating substance. The base granules are preferably soaked during or after being coated with the coating substance.

Description

AMMONIUM NITRILE BLENDING ACTIVATORS IN THE FORM OF COATED GRANULES DESCRIPTIVE MEMORY Bleach activators are important constituents in detergents, salts for stain removal and detergents for dishwashing. They allow a bleaching action even at relatively low temperatures by reacting them with a source of hydrogen peroxide, in most cases perborates or percarbonates, to release an organic peroxycarboxylic acid or when the ammonium nitriles are added as activators, they form a peroxyidic acid as a bleaching agent. Representative examples of bleach activators are, for example, NNN'N'-tetraacetylethylenediamine (TAED), glucose pentaacetate (GPA), xylose tetraacetate (TAX), sodium 4-benzoyloxybenzenesulfonate (SBOBS), sodium trimethylhexanoyloxybenzenesulfonate (STHOBS) ), tetraacetylglucoluril (TAGU), tetraacetylcyanic acid (TACA), di-N-acetyldimethylglyoxine (ADMG) and 1-phenyl-3-acetylhydantoin (PAH). Reference can be made, for example, to GB-A-836 988, GB-A-907 356, EP-AO 098 129 and EP-AO 120 591. Cationic bleach activators containing a quaternary ammonium group have gained importance to over time as they are highly effective bleach activators. Said cationic bleach activators are described, for example, in GB-A-1 382 594, US-A-4 751 015, EP-AO 284 292 and EP-AO 331 229. In connection with this, the ammonium nitriles of the formula: they constitute a particular class of cationic bleach activators. Compounds of this type and their use as bleach activators in bleaching agents are described in EP-A-303 520, EP-A-464 880, EP-A-458 396 and US-4 883 917. In all the compounds described in these documents, the nitrogen atom of the ammonium group is replaced by alkyl, alkenyl or aryl groups. An additional class of ammonium nitriles is described in the German patent application 19605526. The high reactivity and sensitivity of the bleach activators to hydrolysis, particularly in the presence of alkaline detergent constituents, however, require that said ammonium nitriles they are granulated to ensure an adequate shelf life and to release the bleaching effect only during washing. In the past, numerous auxiliaries and processes have been proposed to granulate these substances. EP-A-0 037 026 describes a process for easily producing soluble activator granules comprising from 90 to 98% activator with 10 to 12% cellulose ethers, starch or starch ethers. Granules consisting of bleach activators, film-forming polymers and carboxylic acid, hydrocarboxylic or organic carboxylic C3-C6 ether added are specified in WO 90/01535. EP-AO 0468 824 discloses granules comprising bleach activator and a film-forming polymer that is more soluble at a pH of 10 than at a pH of 7. DE-A-44 39 039 describes a process for producing activator granules by mixing a dry bleach activator with a dry, inorganic binder material containing water of hydration, which compacts this mixture to form relatively large agglomerates, and crushes these agglomerates to the desired grain size. A production process without water, by compacting the bleach activator with at least one auxiliary water-swellable, without the use of water, is known from EP-AO 075 818. The disadvantages of these activator granules are that the properties of the granules are essentially fixed by the binder and by the granulation method used, and that the resulting granules, in addition to the advantages described in the literature, frequently have certain disadvantages as well as, for example suboptimal release of active substance, low abrasion resistance , high dust content, inadequate shelf life, separation within the powder or damage to fabric color when used in detergents and cleaning compositions. To give defined properties of granules, usually a coating step is carried out, subsequent to the granulation step. Common methods are coating in mixers (mechanically induced fluidized bed) or coating in fluidized bed apparatus (pneumatically induced fluidized bed). For example, WO 92/13798 describes, for a bleach activator, coating with a water soluble organic acid that melts above 30 ° C, and WO 94/03305 describes the fact of coating with a soluble acidic polymer. in water to reduce the color damage for washed clothes. WO 94/26862 describes the coating of granules consisting of the bleach activator and water soluble polymer and / or alkali soluble polymer with an organic compound that is melted between 30 ° C and 100 ° C to reduce the separation in the final product pulverulent. In this case, the activator granules are placed in a Lódige grid mixer, which circulates at 160 to 180 rpm at room temperature, without using the pelletizer, and are subsequently sprayed with hot molten material. A disadvantage of this method is the poor coating quality, which, while producing a reduction in the separation in the pulverulent finished product, has no effect on the other properties of the granule, such as release of active substance, abrasion resistance, content of dust or shelf life, for example. The positive effect on the separation behavior can probably be attributed to a drop solidification of the coating substance on the surface of the granule allowing the individual granules to bind to the product in bulk.

The object of the present invention was to develop a coating process for activator granules with ammonium nitrile as an activator, which made it possible to adjust the properties of the granule on a wide scale while at the same time making optimum use of the coating material. This object was achieved by coating with a water-soluble substance. Granules coated in this way can be thermally conditioned during or after coating. The invention further provides granules coated with an ammonium nitrile and a process for the preparation of coated granules of an ammonium nitrile comprising coating base granules of an ammonium nitrile with a water soluble coating substance. These coated granules can be thermally conditioned during or subsequent to the coating. The base granules that can be used are all the ammonium nitriles that in granulated form have a melting point above 60 ° C. Particularly suitable granules in connection therewith, are the ammonium nitriles which were described in the aforementioned literature. Particular preference is given to the ammonium nitriles of the formula wherein R1 and R2 are C? -C4 alkyl, and X is an anion, for example, chloride or methosulfate. The base granules may comprise one or more of these ammonium nitriles or in addition also bleach activators of another structure, for example N, N, N ', N'-tetraacetylenediamine (TAED), glucose pentaacetate (GPA), tetraacetate xylose (TAX), sodium 4-benzoyloxybenzenesulfonate (SBOBS), sodium trimethylhexanoyloxybenzenesulfonate (STHOBS), tetraacetylglucoiuryl (TAGU), tetraacetylcyanic acid (TACA), di-N-acetyldimethylglyoxine (ADMG) and 1-phenyl-3-acetylhydantoin (PAH) ). These base granules may include customary granulation auxiliaries, which have to have a melting point above 60 ° C, preferably above 100 ° C. Suitable auxiliaries are film-forming polymers, for example cellulose ethers, starch, starch ethers, homopolymers, copolymers and graft copolymers of unsaturated carboxylic acids and / or sulfonic acids and also salts thereof; organic substances, for example cellulose, interlaced polyvinylpyrrolidone, or inorganic substances, for example silicic acid, amorphous silicates, zeolites, bentonites, alkali metal phyllosilicates of the formula MM'Six? 2x -? * and H2O (M, M '= Na , K, H, x = 1.9-23, y = 0-25), orthophosphates, pyrophosphates and polyphosphates, phosphonic acids and their salts, sulphates, carbonates and bicarbonates. Depending on what is required, these granulation aids can be used as individual substances or as mixtures.

In addition to the bleach activator and the granulation aid, the bleach activating base granules may also include additional additives that improve such properties, for example, shelf life and bleach activation. Such additives include inorganic acids, organic acids, for example mono- or polybasic carboxylic acids, hydroxycarboxylic acids and / or ethercarboxylic acids, and also salts thereof, complexing agents, metal complexes and ketones. Depending on what is required, the aforementioned additives can be used as individual substances or as mixtures. The base granules are prepared by mixing the dry bleach activator with the dry granulation aid, compacting this mixture to give relatively large agglomerates and grinding these agglomerates to the desired particle size. The weight ratio of the bleach activators to the granulation aid is generally from 50: 5 to 98: 2, preferably from 70:30 to 96: 4. The amount of additive depends particularly on this type. For example, acidifying additives and organic catalysts are added to increase the yield of the peracid in amounts of 0-20% by weight, in particular in amounts of 1-10% by weight, based on the total weight, where the metal complexes are added. in concentrations on the ppm scale. Suitable coating substances are all compounds or mixtures thereof which are in solid form at room temperature and which soften or melt on the scale of 30 to 100 ° C. Examples are: C8-C31 fatty acids (eg, lauric, myristic, stearic acid); C8-C3 fatty alcohols ?; polyalkenyl glycols (for example, polyethylene glycols having a molar mass of about 1000 to 50,000 g / moles); non-ionic (for example C8-C31 polyalkoxylated fatty alcohol with about 1 to 100 moles of EO); anionics (eg, alkanesulfonates, alkylbenzenesulfonates, α-olefinsulfonates, alkyl sulfates, alkyl ether sulphates having C 8 -C 31 hydrocarbon radicals); polymers (for example, polyvinyl alcohols); waxes (for example, montan waxes, paraffin waxes, ester waxes, polyolefin waxes); silicones. Within the coating substance that softens and melts on the scale from 30 to 100 ° C there may be additional substances, which are not softened or melted on this temperature scale, in dissolved or suspended form, examples may be polymers (for example example, homopolymers, copolymers or graft copolymers of unsaturated carboxylic acids and / or sulfonic acids and alkali metal salts thereof, cellulose ethers, starch, starch ethers, polyvinylpyrrolidone); organic substances (for example, mono- or polybasic carboxylic acids, hydroxycarboxylic acids or ethercarboxylic acids having from 3 to 8 carbon atoms, and salts thereof); colorants; inorganic substances (for example, silicates, carbonates, bicarbonates, sulphates, phosphates, phosphonates).

Depending on the desired properties of the coated activator granules, the content of coating substance may be from about 1 to 30% by weight, preferably from 5 to 15% by weight, based on the coated activator granules. The coating substances can be applied using mixers (mechanically induced fluidized bed) and fluidized bed apparatus (pneumatically induced fluidized bed). Examples of possible mixers are grid mixers (continuous and discontinuous), ring bed mixers or other Schugi mixers. If a mixer is used, the thermal conditioning can be performed in a granular preheater and / or directly in the mixer and / or in a fluidized bed downstream of the mixer. The coated granules can be cooled using granule coolers or fluidized bed coolers. In the case of fluidized bed apparatus, the thermal conditioning is carried out by means of the hot gas which was used to fluidize. The granules coated by the fluidized bed method, as well as the mixer method, can be cooled by means of a granule cooler or a fluidized bed cooler. Both in the mixing method and in the fluidized bed method, the coating substance can be sprayed by means of a nozzle apparatus for a single substance or by means of a nozzle apparatus for two substances. The optional thermal conditioning comprises a heat treatment at a temperature of 30 to 100 ° C but not higher than the melting or softening temperature of the respective coating substance. It is preferred to operate at a temperature that is just below the melting or softening temperature. The grain size of the coated bleach activator granules is from 0.1 to 2.0 mm, preferably from 0.2 to 1.0 mm and, with particular preference, from 0.3 to 0.8 mm. The precise temperature during the thermal conditioning or the difference in temperature from the melting point of the coating substance depends on the coating speed, the thermal conditioning time and the properties desired for the coated bleaching activator granules, and must be determined in preliminary experiments for the particular system. The period for thermal conditioning is from about 1 to 180, preferably from 3 to 60 and, with particular preference, from 5 to 30 minutes. The advantage of this thermal conditioning is that the liquid coating material does not solidify very quickly and thus has the possibility of running as a thin film on the surface of the granules. This produces an extremely uniform coating of the grain in a thin layer with the coating substance, and an optimum coating effect for the use of a minimum amount of coating substance. In conventional processes, that is, those without a thermal conditioning step, the solidification of the individual droplets on the surface of cold granules is too rapid. As a result, the surface is covered only with fine individual drops and still has large coating gaps. As a result, the desired coating effect is not obtained in its entirety or a larger amount of coating substance is required to obtain the desired coating effect. However, in the latter case, the content of the activating substance is reduced, which in most cases is not desired. By means of the novel process it is possible to adjust the properties of the ammonium nitrile granules within the broad scales to the desired specifications by means of an appropriate choice of the coating substance, the coating speed and the temperature regime of the process. In this particular context, it is possible to optimize in a predetermined manner the following properties of the activator granule. 1. Optimal time release of active substance To avoid interaction between the bleaching system and the enzyme system it is useful to couple a slightly delayed reaction and release of active substance from the bleaching system with a rapid enzyme action. In this way the enzymes can develop their washing power completely within the first minutes of the washing process without being damaged by the bleaching system. Only after the enzymes have done their work is the whitening process set in motion by reaction of the bleach activator with the source of hydrogen peroxide. An appropriate coating of the bleach activator makes it possible to adjust the reactivity, i.e. the rate of dilution or the rate of peracid formation, specifically for the enzyme system. The method allows controlled adjustment of the rate of peracid formation at the same time while having a minimum amount of coating substance and therefore maximum activator content. 2. Increased abrasion resistance When coating granules with softening or melting substances it is possible to increase the abrasion resistance of the activator granules. The increase in abrasion resistance is greater the better the coating of the granule surface with the coating substance. The novel coating process makes it possible, with a minimum coating speed, to obtain an optimum flow of the coating substance on the granule surface and thus an optimum improvement of the abrasion resistance. 3. Extending shelf life When a detergent and cleaning composition is stored there may be a reaction at the boundary between the activator grain and a grain directly adjacent to the source of hydrogen peroxide, with subsequent loss of active oxygen and thus a failure uncontrolled bleaching system. By means of an optimum coating, just as it is possible only through the novel coating process, a protective layer is built up to the grain size, whose layer subsequently prevents the reaction of the activating grain with the grain of the peroxide source hydrogen during storage. When the water-soluble and / or low-melting coating substances are used, it is not possible to obtain the bleaching performance required in the washing process. The granules obtained in this way are directly suitable for use in detergent and cleaning compositions. They are ideal for use in heavy duty detergents, stain removal salts, dishwashing detergents, cleaning powders and general purpose denture cleaners. In said formulations, the granules of the invention are used in most cases together with a source of hydrogen peroxide. Examples thereof are, perborate monohydrate, perborate tetrahydrate, percarbonates, and hydrogen peroxide adducts with urea or with amine oxides. The formulation can also further characterize the detergent constituents of the prior art, such as organic or inorganic builders and co-builders, surfactants, enzymes, wash additives, optical brighteners and fragrance.

EXAMPLES EXAMPLE 1 Preparation kg of a mixture of 92% by weight of ammonium nitrile (trimethylammonium acetonitriletoluensulfonate) and 8% by weight of bentonite (Laundrosil DGA) are intensively mixed in a 50 liter Lódige mixer at a speed of 70 rpm for a period of 10 minutes. This homogeneous mixture is then compacted into flakes in a Pharmapaktor roller compactor (Bepex (DE)) at a pressure force of 50 to 60 kN; subsequently, the flakes are crushed in a two-stage grinding process, pre-milled with sawn disc rollers (Alexanderwerk (DE)) and crushed in a sieve (Fewitt (DE)) at a mesh size of 2000 μm. This gives 5.3 kg of granules, referred to as G1, which have a particle size distribution of 200 to 1600 μm. (Yield: 53%), and also 2.8 kg of fine material < 200 μm (28%), which can be recycled when recompacted, and 1.9 kg of coarse material > 1600 μm (19%), which can be processed by regrind.

EXAMPLE 2 Coating by the fluidized bed method with downstream thermal conditioning 500-600 g of granules (G1) were placed in a fluidized bed (Strea 1 fluidized bed apparatus from Aeromatic) and sprayed with a hot melt material (approximately 80 ° C) of stearic acid. For comparison purposes, in one case the fluidized bed was operated at low temperatures and after spraying it was cooled again for approximately 5 minutes. In the other case, according to the preferred procedure, the coated granules were placed back into the fluidized bed and subjected to thermal conditioning. Up to this point, the fluidized bed was gradually heated to temperatures of about 65 to 70 ° C and this temperature of the product remained constant for about 5 to 8 minutes. The thermally conditioned product was subsequently cooled in stages. The coating quality of the products was evaluated by determining the rate of peracetic acid formation at a temperature of 20 ° C. The slower the formation of peracetic acid, the better the degree of coating achieved. To determine the rate of peracetic acid formation, 1 liter of distilled water, 8.0 grams of WMP test detergent and 1.5 grams of sodium perborate monohydrate were placed in a 2 liter glass beaker at 20 ° C and the mixture was agitated from about 250 to 280 rpm using a magnetic stirrer. Subsequently, after 1 to 2 minutes, 0.5 g of coated granules were added. After 1 minute a 50 ml aliquot was removed by means of a pipette and placed in 150 grams of ice and 5 ml of 20% strength acetic acid in an Erlenmeyer flask. Immediately after the addition of 2 to 3 ml of potassium iodide solution at 10% concentration, the mixture was titrated to the potentiometric endpoint with 0.01 molar sodium thiosulfate solution (Titroprocessor 716 DMS from Metrohm) and the amount of Peracetic acid was calculated from an amount of sodium thiosulfate consumed. Then additional samples were taken at intervals of 2 to 5 minutes and titrated as described. The entire procedure was repeated until equal amounts or descendants of peracetic acid were found after 3 successive titrations. The maximum amount of peracetic acid found was taken as 100% and on this basis, finally, the amount of peracetic acid formed after 5, 10 and 20 minutes was determined in percent as a measurement of the rate of peracetic acid formation.

TABLE 1 Rate of peracid formation by uncoated granules I and granules I coated in the fluidized bed method. with or without subsequent thermal conditioning: The coating delays to a large extent the release of peracid. By means of thermal conditioning, it is possible to cause a remarkable improvement in the coating quality, which is expressed by the delay in the formation of peracid, for the same coating speed (comparing products 2 and 4 and products 3 and 5). To achieve an optimum coating quality, an amount of 10% coating substance (product 2) is sufficient to give suitable thermal conditioning.

EXAMPLE 3 Shelf Life of Ammonium Nitrile Granules in Detergent Formulations The shelf life was examined in easily constructed folded boxes (height: 6.5 cm, width 3.2 cm, depth 2.2 cm) at 38 ° C and relative atmospheric humidity at 80% (RH) for a period of 28 days. Each folded box was filled with a homogeneous mixture of 8.0 grams of WMP test detergent, 1.5 grams of sodium percarbonate and 0.5 grams of ammonium nitrile granules for examination and then sealed at the top with Tesafilm. All samples were mixed and delivered in the boxes on the same day. The folded boxes filled later were placed at a sufficient distance from each other in the climatically controlled cabinet and stored at 38 ° C / 80 HR. After storage periods of 0, 3, 6, 9, 15, 23 and 28 days the samples were removed from the cabinet, the total sample was introduced at 20 ° C in 1 liter of distilled water, while stirring with a magnetic stirrer (250 to 280 rpm), and 1 gram of sodium percarbonate was added. The subsequent determination of the amount of peracid formed was as indicated in example 2. The ammonium nitrile content of the sample was subsequently calculated from the maximum peracid value found. The durability of ammonium nitrile represents the percentage of ammonium nitrile content of the sample after storage related to the ammonium nitrile content of the non-stored sample.

TABLE 2: Shelf life in detergent formulations of ammonium nitrile granules coated by the fluidized bed method.

Durability of ammonium nitrile Ammonium nitrile granules (G1) after storage Od 3d 6d 9d 15d 23d 28d G1 100 29 15 12 10 7 6 G1 + 10% stearic acid, 100 88 69 62 57 55 55 thermally conditioned G1 + 10% stearic acid, 100 69 35 30 28 26 23 not thermally conditioned EXAMPLE 4 The shelf life of the coated granules was further examined under conditions simulating those found in practice in an Óko-Lavamat 6753 multi-component washing machine (AEG, Nuremberg) on fabrics subjected to bleach testing in the presence of a laundry. of pure test. In accordance with the dosing instructions for the water hardness region, 3.70 grams of the reference detergent (WMP) was introduced into the detergent compartments of the washing machine. The bleaching component introduced in the detergent compartment was 8.0 grams of percarbonate and also a) 3.18 grams of G1 granules + 10% stearic acid (82%), coated, thermally conditioned b) 3.18 grams of G1 granules + 10% acid stearic (82%), coated, not thermally conditioned c) 2.93 grams of G1 granules (92%), uncoated. For comparison purposes, ammonium nitrile (trimethylammonium acetonitriltoluensulfonate) (2.7 grams) powder (Ex. 4d) was examined. The stabilizing material that was used is 2 kg of sponge cloth, and the dirt of the test consists of 10 bleachable dirt (tea, red wine, curry, grass, from the Krefeld Laundry Research Center). The clothes were washed in a main wash at 40 ° C. The evaluation was carried out to determine the degree of whiteness after washing by the addition of reflectance differences.

TABLE 3 Reflectance differences of bleaching components a) -d) T = 40 ° C, tea, red wine, curry, grass

Claims (13)

NOVELTY OF THE INVENTION CLAIMS

1. Ammonium nitrile coated bleach activator granules, obtained by coating granules of ammonium nitrile base with a water soluble coating substance, wherein the coating substances are fatty acids, fatty alcohols, polyalkylene glycols, nonionic surfactants, anionic surfactants, polymers, waxes and / or silicones that soften or melt on the scale of about 30 to 100 ° C.

2. The coated bleach activator granules according to claim 1, wherein the granules comprise an ammonium nitrile of the formula wherein R1 and R2 are C1-C4 alkyl and X is an anion.

3. The coated bleach activator granules according to claim 1, further characterized in that the granules of ammonium nitrile base have a melting point above 10OX.

4. - The coated bleach activator granules according to claim 1, further characterized in that the coating substance has a softening or melting point in the range of 30 to 100 ° C.

5. The coated bleach activating granules according to one or more of claims 1 to 4, further characterized in that the thermal conditioning is carried out during or after the coating step at temperatures in the vicinity of the softening or melting point of the coating substance.

6. The coated bleach activator granules according to one or more of claims 1 to 5, further characterized in that the ammonium nitrile base granules additionally comprise one or more bleach activators that are not ammonium nitrile.

7. The coated bleach activating granules according to one or more of claims 1 to 6, further characterized in that the coating substances comprise fatty acids, fatty alcohols, polyalkylene glycols, nonionic surfactants, anionic surfactants, polymers, waxes and / or silicones.

8. The coated bleach activating granules according to one or more of claims 1 to 7, further characterized in that the coating substance comprises polymers, organic substances and / or inorganic substances in dissolved or suspended form.

9. The coated bleach activator granules according to one or more of claims 1 to 8, further characterized in that the content of the coating substance is from 1 to 30% by weight, preferably from 5 to 15% by weight, based on the coated bleach activator granules.

10. The coated bleach activator granules according to one or more of claims 1 to 9, further characterized in that the coating substance is applied in a mixer or in a fluidized bed apparatus. 1.

The coated bleach activator granules according to one or more of claims 1 to 10, further characterized in that the particle size of the coated bleach activator granules is 0.1 to 2.0 mm, preferably 0.2 to 1.0 mm. and in particular preferably from 0.3 to 0.8 mm.

12. The coated bleach activator granules according to one or more of claims 1 to 11, further characterized in that the base granules contain up to 20% by weight, based on the weight of the base granules, of one or more additives selected from a group consisting of inorganic acids, organic acids, complexing agents, ketones and metal complexes.

13. - A detergent, a cleaning, bleaching or disinfectant composition comprising coated bleach activator granules according to one or more of claims 1 to 12.