EP0563083A1

EP0563083A1 - Granulate with encapsulated bleaching activator.

Info

Publication number: EP0563083A1
Application number: EP92900270A
Authority: EP
Inventors: Hans-Josef Beaujean; Gonzalez Rene-Andres Artiga
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 1990-12-19
Filing date: 1991-12-04
Publication date: 1993-10-06
Anticipated expiration: 2011-12-04
Also published as: DE4040654A1; JPH06503111A; DE59107903D1; EP0563083B1; ES2088125T3; ATE138974T1; KR930703427A; WO1992011349A1

Abstract

Granulates containing bleaching activators can be used especially in non-aqueous liquid detergents if they are fully encapsulated in a coating agent. The coating agent is chemically inert to the bleaching activator and is soluble only in negligibly small quantities in liquid, non-ionic tensides which are usually present in non-aqueous detergents. The granulate consists of at least 80 % wt. of particles with a diameter of between 0.1 and 0.5 mm.

Description

"Granules with coated bleach activator"

The invention relates to a granulate which contains a coated bleach activator, a process for its production and detergents and cleaning agents which, in addition to a bleach, also contain the granules with the coated bleach activator.

Liquid detergents have numerous advantages over powdered or pasty forms of supply, such as better handling, dosing and increased performance compared to greasy soiling. Non-aqueous liquid detergents have the advantage over aqueous liquid detergents in that they can contain bleach in suspended form. Such systems offer significant performance advantages at low temperatures between 15 and 60 ° C only in the presence of a bleach activator. Examples of non-aqueous liquid detergents with bleach and bleach activator are disclosed in German patent applications 3820631, 3728047, 35 11 517 and in European patent applications 339999, 339995 and 266 199.

However, the bleach activator is subject to hydrolytic and alcoholic degradation in the presence of water and alcohol. This problem was already known, albeit to a lesser extent, from the solid detergents containing bleach and activator. Here, the durability of the finished powder in particular was increased by coating the activator with a coating material. This protection prevented the bleach activator from reacting both with the hydrogen-peroxide-releasing compound and with the aqueous and alkaline components of the detergent, for example alkali carbonate or alkali silicate.

For example, German patent application 11 62 967 describes an N-containing bleach activator coated with a solid substance, which contains at least two acyl groups or mixtures of such compounds which are attached to the same nitrogen atom and which is used in solid detergents. Activators include tetraacetylalkylenediamines and tetraacetylarylenediamines, and in particular tetraacetylethylenediamine. Solid coating agents include substances such as stearic acid and polyethylene glycols and also condensation products of ethylene oxide and propylene oxide. However, compounds such as polyvinyl alcohol, carboxymethyl cellulose (CMC), cetyl alcohol and fatty acid alkanolamides are particularly suitable. It is recommended to granulate the activator before coating. The coating is carried out in devices suitable for this purpose. The solid coating material, which is dissolved in water or an organic solvent, is sprayed onto the activator in finely divided form, whereupon the coated material is dried. The amount of the coating material used is 1 to 30% by weight, based on the bleach activator. No statement is made about the particle size of the coated activator.

A coated bleach activator is also known from German patent application 20 48 331, which is used in solid, powdery to granular compositions. The conventional bleach activators, which are present as solid particles, are surrounded by a shell of water-soluble and / or water-insoluble substances which are inert to the activator, the activators making up 5 to 50% by weight and the shell material making up 50 to 95% by weight of the activator component. The bleach activator, whose grain size is generally between 0.005 to 1 mm, and preferably 0.01 to 0.8 mm and in particular up to 0.2 mm, is wetted or sprayed with aqueous liquids in any order and then with the solid Hü11 substances mixed, agglomerated or granulated. Pure water, solutions or dispersions of cellulose, protein and starch derivatives, such as CMC, MC, gelatin, dextrins and casein, but also polyvinyl alcohol or polyethylene glycol are suitable as aqueous liquids. Suitable solid coating substances are inorganic salts, preferably those which can bind water of crystallization, such as phosphates, carbonates, sulfates, alkali silicates, but also microcrystalline silica, magnesium, tin, titanium salts and dioxides, and also polymers, such as polyethylene or Polypropylene powder. The coated bleach activator is powdery to granular with a particle size of 0.3 to 3 mm. However, these activator components only contain the bleach activator up to a maximum of 50% by weight, so they can only be used where the high proportion of coating materials does not interfere. German patent application 22 20 296 discloses a granulate with a coated bleach activator, the coating agent being chemically inert to the activator and at least 40% by weight, preferably at least 60% by weight, of the bleach activator consisting of the bleach activator. However, the practical upper limit for the content of the activator in the granulate is 80% by weight. The granules have a particle size of 0.3 to 3 mm. The particle size of the activator used should be as small as possible and a maximum of 0.15 mm. The activator is first mixed with a carrier and then coated together with this carrier with an outer, coherent protective layer. Paraffins, fatty acids and fatty acid esters with at least 8 carbon atoms and dispersion auxiliaries for paraffin, such as alkyl sulfates and alkylbenzenesulfonates, are suitable as carriers. Polymeric alcohols and (co) polymeric carboxylates and (poly) saccharides are predominantly used as coating agents. The carrier material and the protective layer can also consist of the same material, so that the production process, which is in itself two-step, can also take place in one step.

German patent application 23 38 412 describes coated bleach activators made from 10 to 70% by weight of a conventional bleach activator and 30 to 90% by weight of a mixture of C ₁₂ -, C ₂₄ -fatty acids and C12-, C ₂₀ -fatty alcohols with 0 to 5 ethylene oxide groups (E0) in a ratio of 10: 1 to 2: 1 are known. At least 70% by weight of the particles have a size between 0.1 and 1 mm, while 3.5 to 25% by weight have a particle size between 1.0 and 1.6 mm. The sum of fine fractions between 0.01 and 0.1 mm and coarse fractions above 2.5 mm is a maximum of 30% by weight.

German patent application 26 51 254 discloses coated bleach activators which are obtained by spraying an agglomerating agent or a granulating agent onto the bleach activator. Methods are used which are known to the person skilled in the art, for example spraying on trickle film, spraying fluidized bed or drum agglomeration technology. Agglomerated bleach activators have a preferred particle size of 0.8 to 1.8 mm, while granular bleach activators have a particle size of 0.5 to 1.8 mm and preferably 1.0 to 1.6 mm. The patent application teaches that the specified lower value of the Particle diameter is to be regarded as a critical factor in that a granular, crystalline activator component with an average particle size distribution of less than 0.5 mm tends to have a markedly reduced storage stability.

German patent application 30 11 998 describes storage-stable bleach activators which are prepared by first mixing the activator dry with a powdered granulating aid, moistening the dry mixture with water or an aqueous solution of the granulating aid and then granulating. Due to the homogenizing granulation, part of the granulation aid is distributed on the surface of the activator and part is contained in the core of the granulate. The bleach activators obtained have from 65 to 75% by weight a particle size from 0.5 to 1.5 mm. Finer and coarser parts are screened off.

The known coated bleach activators thus either have a low active ingredient content, which is unsatisfactory, and / or they contain particles, the size of which can be in a wide range. Coarser particles with a diameter of 1 mm and above are preferred, whereas particles with a diameter of less than 0.5 mm have so far been undesirable in larger quantities because of their reduced storage stability. Solids, the grain size distribution of which covers wide areas and which contain a high proportion of coarser grains with diameters of 1 mm and above, are not suitable for use in liquid detergents, since the dispersibility of the particles decreases with increasing size and these tend to sedimentation .

There was a need for bleach activators in a form which does not have the disadvantages mentioned above and which can be used in detergents and cleaning agents, in particular in non-aqueous liquid detergents.

The invention accordingly relates to granules with a coated bleach activator, the granules being completely coated with a coating agent which is chemically inert to the bleach activator. The granules consist of at least 80% by weight of particles whose diameter is between 0.1 and 0.5 mm and preferably between 0.1 and 0.4 mm. A maximum of 15% by weight of the granules consist of particles which have a diameter above 0.5 mm, preferably above 0.4 mm, and a maximum of 5% by weight of particles with a diameter smaller than 0.1 mm.

The known N- and 0-acylated compounds, in particular N-acylated amines, diamines, amides and glycolurils, are suitable as bleach activators. These are e.g. B. tetraacetylmethylene diamine, tetraacetylethylene diamine (TAED), diacetylaniline, diacetyl-p-toluidine, 1,3-diacetyl-5,5-dimethylhydantoin, tetraacetylglycoluril, tetrapropionylglycoluril, 1,4-diacetyl2,5-diketopiacyl and , 6-dimethyl-2,5-diketopiperazine. Other suitable bleach activators are triazine derivatives, in particular 1,3,5-tris (dimethylaminopropyl) perhydro-1,3,5-triazine and 1,5-diacetyl2,4-dioxohexahydro-1,3,5-triazine (DADHT). A preferred bleach activator is tetraacetylethylenediamine, which can be used as granules or as a powder. It is particularly advantageous to use a tetraacetylethylene diamine granulate whose particle size is at least 90% by weight and in particular at least 95% by weight between 0.1 and 0.8 mm.

The solid coating agents have been shown to be chemically inert to the bleach activator, ie the breakdown rate for the granules according to the invention containing the bleach activator and stored for 4 months is less than 1% by weight. Furthermore, the solid coating agents must be rapidly soluble in water or aqueous solutions, but should be found in liquid nonionic surfactants, which are usually contained in non-aqueous liquid detergents, e.g. ethoxylated C ₁₂ -C ₁₈ fatty alcohols with 2 to 7 mol ethylene oxide (E0 ), only solve in negligibly small amounts. The solubility of the solid coating agent at 25 ° C. is preferably less than 5 g of coating agent per 1000 g of C ₁₂ -C ₁₈ fatty alcohol with 5 EO and in particular less than 2 g of coating agent per 1000 g of C ₁₂ -C ₁₈ fatty alcohol with 5 EO. If the solubility rises above these values, this does not have a negative effect on the stability of the granules per se, but it is then no longer guaranteed that the coating agent is not at least partially used when used in non-aqueous liquid detergents of the usual composition is solved. This would result in granules that would no longer be completely covered.

Suitable solid coating agents for the purposes of this invention are in particular water-soluble polymeric compounds, such as starch or starch or cellulose derivatives, solid polymeric alcohols, for example polyvinyl alcohol and polyethylene glycols, homo- and copolymeric carboxylates, and anionic surfactants.

The water-soluble starch or cellulose derivatives include, in particular, starch ethers and cellulose ethers. Examples of cellulose ethers are methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, methyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose, carboxymethyl cellulose (as the sodium salt). For example, depolymerized starch can be considered as starch. Suitable starch ethers are, for example, carboxymethyl starch, hydroxyethyl starch and methyl starch. Sodium carboxymethyl cellulose and starch have proven to be particularly suitable. Gelatin is also used with particular advantage as a coating agent.

Other suitable coating agents are solid polyethylene glycols which have, for example, a relative molecular mass (M _r ) between 10,000 and 20,000. Polyvinyl alcohol and homo- and copolymeric carboxylates, such as polyacrylates, polymethacrylates and in particular copolymers of acrylic acid with maleic acid, preferably those from 50% by weight to 10% by weight of maleic acid, can also be used. The relative molecular weight of these hotnopolymers is generally between 1,000 and 100,000, that of the copolymers between 2,000 and 200,000, preferably 50,000 to 120,000, based on free acid. A particularly preferred acrylic acid-maleic acid copolymer has a relative molecular weight of 50,000 to 100,000. Other suitable, albeit less preferred, compounds of this class are copolymers of acrylic acid or methacrylic acid with vinyl ethers, such as vinyl methyl ethers, in which the proportion of acid is at least 50% by weight.

Further examples of coating agents which can be used according to the invention are so-called host molecules or cage compounds, the molecules how the specified bleach activators can enclose inside. A preferred cage compound is cyclodextrin. TAED and cyclodextrin are used with particular advantage in a molar ratio of 1: 1 to 1: 2.

It is also possible to use anionic surfactants, in particular C ₉ -C ₁₃ alkylbenzenesulfonates, C ₁₂ -C ₁₈ fatty alcohol sulfates and C ₁₂ -C ₁₈ fatty acid soaps and mixtures of these, as solid coating agents.

The granules according to the invention have a bleach activator content of preferably at least 70% by weight and in particular between 75 and 92% by weight. The solid coating agent is preferably present in amounts of 8 to 25% by weight, in particular 8 to 20% by weight, and particularly advantageously 10 to 18% by weight, based on the total of bleach activator and coating agent Contain granules.

Due to the manufacturing process, the granules may contain small amounts of free water which is not bound as water of crystallization or in a comparable form. Amounts up to 5% by weight are tolerable. However, the granules preferably contain 0 to 3% by weight of water.

In order to accelerate the dissolving process when subsequently used in an aqueous bleaching bath, small amounts of known powdery disintegrants which are customary in the tablet industry can also be added, provided that the cellulose and starch ethers which may be used do not automatically develop a sufficient explosive effect. Usable disintegrants include partially degraded starch, polyvinylpyrrolidone, formaldehyde casein and swellable magnesium aluminosilicates (Veegum). The proportion of such disintegrants can be 0.5-2% by weight, based on the granules according to the invention.

Preferred granules consist of particles, of which at least 85% by weight have a diameter of 0.1 to 0.4 mm (sieve analysis). The fine fraction with a diameter of less than 0.1 mm is preferably at most 3% by weight, while the content of particles with a diameter above 0.4 mm to 0.8 mm should be at most 12% by weight. With a special advantage granules are used which do not contain any particles whose diameter is 1 mm and above.

Surprisingly, the granules according to the invention which contain a coated bleach activator and have the stated particle size distribution, which is shifted towards significantly smaller values compared to the prior art, have an astonishingly high storage stability. The degradation rate for anhydrous granules that have been stored for 4 months or even up to 7 months is less than 1% by weight. Likewise, the rate of degradation of the bleach activator when using the granules according to the invention in non-aqueous agents, in particular in non-aqueous liquid detergents, is reduced by 25 to 60% by weight in comparison with non-coated bleach activators. A further advantage of the particle size distribution according to the invention lies above all in the better dispersibility of the granules containing the bleach activator in non-aqueous agents, which results in an increased sedimentation stability of these agents.

The invention further relates to a process for producing the granules according to the invention containing the coated bleach activator, the solid coating material, which is dissolved in water, being sprayed onto the bleach activator in finely divided form, whereupon the coated granules are dried. The coating can be carried out in all devices suitable for this purpose and known to the person skilled in the art, for example in ploughshare mixers and mixers with partial or complete swirling. The granules are preferably sprayed in a fluidized bed in which the bleach activator, which is used as a powder or as granules, is sprayed with aqueous solutions, preferably 6 to 35% by weight and in particular 8 to 30% by weight, aqueous solutions of the coating agent and at the same time is dried by warm air at temperatures of preferably 50 to 80 ° C and in particular 60 to 75 ° C. The spray rates are preferably in a range from 5 to 30 and in particular from 7 to 25 g / min. The coating in a fluidized bed also has the advantage that, depending on the spray rate, granules are obtained in which the shell - apart from slight fluctuations - has a uniform thickness. The dried granules are then subjected to a sieve analysis. While the fine fractions (particle size smaller than 0.1 mm) are preferably directly recycled, any coarse fractions (particle size above 0.8 mm) which may be present can first be comminuted and then recycled.

In a further embodiment, the invention relates to the use of the granules according to the invention with coated bleach activator in detergents and cleaning agents. The detergents and cleaning agents can have a solid, pasty or liquid consistency. However, they are said to be essentially non-aqueous. In the context of this invention, “essentially non-aqueous” means that the content of free water not bound as water of crystallization or in comparable form preferably does not exceed 3% by weight and in particular in the range from about 0 to 2% by weight. % lies. In addition to the inorganic per-compounds which serve as bleaching agents and which provide H2O2 in water, for example sodium perborate tetrahydrate, sodium perborate monohydrate, sodium peroxycarbonate, and organic per-compounds, for example citrate perhydrate, perbenzoate, peroxophthalate or diperoxydodecanedioic acid, all the others, Contain the usual ingredients of detergents and cleaning agents. These primarily include surfactants, builder substances, polymers, alkaline salts such as sodium carbonate and sodium silicate, graying inhibitors, foam inhibitors, optical brighteners, enzymes, fabric softening agents, dyes and fragrances, neutral salts and organic solvents. In a preferred embodiment, non-aqueous liquid detergents contain 32 to 40% by weight of anionic surfactants, 22 to 27% by weight of ethoxylated fatty alcohols, 10 to 15% by weight of perborate monohydrate, granules which contain 2 to 5% by weight of active substance TAED contains 5 to 12 wt .-% alcoholic solvents and alkali metal salts such as sodium carbonate and / or sodium silicate.

In a further, particularly preferred embodiment, non-aqueous liquid detergents contain 40 to 60% by weight of nonionic surfactants, 10 to 20% by weight of anionic surfactants from the group of the sulfonates and sulfates, 10 to 18% by weight of sodium perborate monohydrate, 2, Granules containing 5 to 6% by weight of bleach activator and 5 to 15% by weight of alcoholic solvents, for example ethanol, isopropanol, butanol, diethylene glycol, diethylene glycol monomethyl ether, triacetin (glycerol triacetate) and liquid polyethylene glycols.

The non-aqueous liquid detergents were stable in storage for at least 3 months both at room temperature and at 40 ° C. With batches that had been stored for a long time, no discontinuation was observed even after 4 months and even after 7 months.

Examples

The examples describe the production of the granules according to the invention with a coated bleach activator.

After loading a mixer with complete swirling of the Aeromatic / Glatt type with TAED granules, which had the particle size distribution given in Table 2, was used by means of a pneumatic spraying device, which is arranged centrally above the air-flowed floor, so that a vertical spray cone is formed , sprayed an aqueous solution of the coating agent. The loading of TAED with the coating agent was in each case 10% by weight of coating agent, based on the sum of TAED and coating agent. All other process parameters such as concentration of the aqueous solution of the coating agent, spray rate and temperature can be found in the examples in Table 1. Post-drying of the granules was not necessary. The free water content in the finished granulate was less than 3% by weight.

Table 2 shows the grain size distribution of a granulate coated with granular carboxymethyl cellulose sodium salt (CMC). Comparable results were obtained for all other granules produced according to Table 1: the proportion of the individual fractions between 0.1 and 0.8 mm fluctuated only by + 10% by weight, based on the values given in Table 2 in each case. The proportion of particles with a diameter of less than 0.1 mm was less than 2.5% by weight and the proportion of particles with a diameter of 1 mm and above was 0% by weight.

Table 1 :

Example coating agent aqueous solution spray rate temperature

No. in% in g / min in ° C

1 polyethylene glycol 30 7 60

M _r 12000

2 sodium dodecylbenzene 20 7 75

sulfonate (90%)

Polyvinyl alcohol 8 8 70

Copolymer of the Na30 10 70 trium salts of acrylic acid and maleic acid,

Sokalan CP 5 ^(R)

(Sales product from BASF)

Gelatin 10 10 68

Strength 8 25 71

CMC (98%) 10 8 70

Methyl cellulose powder 10 8 70 (91.5%, turbidity number 35)

Claims

Patents say

1. Granules with a coated bleach activator, the granules being completely coated with a coating agent which is chemically inert to the bleach activator and at least 80% by weight of particles whose diameter is between 0.1 and 0.5 mm, maximum 15% by weight of particles whose diameter is above 0.5 mm and a maximum of 5% by weight of particles with a diameter of less than 0.1 mm.

2. Granules according to claim 1, characterized in that the bleach activator is tetraacetylethylene diamine.

3. Granules according to claim 1 or 2, characterized in that the solid coating agent at 25 ° C has a solubility of less than 5 g of coating agent to 1000 g of C ₁₂ -C ₁₈ fatty alcohol with 5 EO.

4. Granules according to one of claims 1 to 3, characterized in that the content of the bleach activator 75 to 92 wt .-% and the content of solid coating agent 8 to 25 wt .-%, preferably 8 to 20 wt .-%, based on the total of bleach activator and coating agent.

5. Granules according to one of claims 1 to 4, characterized in that it consists of particles, of which at least 85 wt .-% have a diameter of 0.1 to 0.4 mm, maximum 3 wt .-% a diameter smaller than 0.1 mm and a maximum of 12% by weight have a diameter of above 0.4 mm to 0.8 mm, the granules containing no particles whose diameter is 1 mm and above.

6. A process for producing a granulate with a coated bleach activator, the granulate being completely coated with a coating agent which is chemically inert to the bleach activator, and the granulate being at least 80% by weight of particles whose diameter is between 0.1 and 0 , 5 mm and preferably between 0.1 and 0.4 mm, a maximum of 15% by weight of particles whose diameter is above 0.5 and preferably above 0.4 mm, and a maximum of 5% by weight of particles with a diameter of less than 0 , 1 mm, characterized in that the bleach activator, which is used as a powder or granules, is sprayed with 6 to 35% by weight aqueous solutions of the coating agent in a fluidized bed and at the same time by introducing warm air at temperatures from 50 to 80 ° C is dried.

7. The method according to claim 6, characterized in that the spray rates are between 5 and 30 g / min.

8. Use of granules with a coated bleach activator, the granules being completely coated with a coating agent which is chemically inert to the bleach activator and at least 80% by weight of particles whose diameter is between 0.1 and 0.5 mm, is preferably between 0.1 and 0.4 mm, a maximum of 15% by weight of particles whose diameter is above 0.5 mm and preferably above 0.4 mm, and a maximum of 5% by weight of particles with a diameter smaller than 0.1 mm, in solid, pasty or liquid detergents and cleaning agents, preferably in non-aqueous liquid detergents.