EP0985728B1 - Bleach activator granulate - Google Patents

Description

Bleach activators are important ingredients in compact detergents, patch salts and machine dishwashing detergents. Already at 40 ° C to 60 ° C, they enable a bleaching result comparable to that of cooking linen, by reacting with hydrogen peroxide donors (usually perborates or percarbonates) to release an organic peroxycarboxylic acid.

The achievable bleaching result is determined by the nature and reactivity of the peroxycarboxylic acid formed, the structure of the bond to be perhydrolyzed, and the water solubility of the bleach activator. Many substances are known in the art as bleach activators. These are usually reactive organic compounds having an O-acyl or N-acyl group which are already present in the washing powder mixture, favored by the residual moisture present, with the bleaching agent, e.g. Sodium perborate react when both components are unprotected.

In order to prevent the reaction with the bleaching agent and hydrolysis in the presence of alkaline detergent ingredients and to ensure a sufficient shelf life, the bleach activator is used in granulated and coated form in detergent and cleaner preparations.

For the granulation of these substances numerous adjuvants and methods have been described in the past. In EP-A-0 037 026 For example, a method for producing a readily soluble activator granulate having active contents between 90 to 98% by weight is described. For this purpose, the powdery bleach activator is homogeneously mixed with powdery cellulose or starch ethers and then sprayed with water or an aqueous solution of the cellulose or starch ether, granulated at the same time and then dried. Since starch and cellulose derivatives form only jelly with water, their flowability and adhesive property is inadequate, possess the after the in EP-A-0 037 026 activator granules prepared according to the method described only moderate strength.

To EP-A-0 070 474 For example, similar granules can be prepared by spray-drying aqueous slurries containing the activator and the cellulose or starch ether. However, a better strength of the granules is not achieved. In EP-A-0 374 867 describes another process for the preparation of Aktivatorgranulaten, in which the activator is first moistened with water and then mixed with the powdery auxiliary, preferably sodium carboxymethylcellulose, and granulated. By this process variant, a better coating of the activator particles is achieved with the excipient, which leads to a better storage stability. However, the strength of the granules is not improved.

In EP-A-0 240 057 and EP-A-0 241 962 describes the use of readily water-soluble film-forming polymers as binders in activator granules. Further constituents of the granules described are salts and optionally bentonite. The granules described prove to be very brittle and less resistant to abrasion.

The use of polymers which are hardly soluble at pH 7 and only readily soluble in water at pH 10, as binders in activator granules, optionally in combination with cellulose or starch ethers, is disclosed in US Pat EP-A-0 468 824 described. In this process, the polymer is used as an aqueous dispersion and not as a solution. This results in a disadvantage of a poorer distribution of the polymer in the granules, which is associated with a poorer binding of Aktivatorpartikel and, accordingly, with a poorer granule strength.

Activator granules with organic binders, eg carboxymethylcellulose, and a disintegrant are used by EP-A-0 238 341 described. The content of disintegrant does not improve the strength of the granules. At elevated air humidity, even a slight disintegration of the granules is observed.

EP-A-0 356 700 describes a process for preparing bleach activator wherein a dry mixture of all components is prepared and then sprayed with water or an aqueous solution containing the remainder of the granulation aid dissolved. The funds are characterized by a good storage stability.

Disadvantage of all described granules and granulation is thus a poor abrasion resistance of the activator granules. Since the storage stability of Aktivatorgranulaten in detergents and cleaners with increasing fines significantly decreases, a worse abrasion resistance under normal handling naturally leads to a poorer storage stability.

The object of the present invention was to improve the abrasion resistance and storage stability of activator granules.

Surprisingly, it has been found that the abrasion resistance and storage stability of granules consisting of bleach activators and binders can be significantly improved by addition of about 1 to 5% by weight of readily water-soluble film-forming, optionally acidic polymers.

The invention relates to the use of bleach activator granules. as defined in the phrases.

Basis for the granules according to the invention are customary and known bleach activators, for example from the group of the activated carboxylic acid esters, carboxylic anhydrides, lactones, acylals, oxamides, N-acylated amines, amides, lactams, acyloxybenzenesulfonates, acylated sugars and nitriles or nitriles which carry a quaternary ammonium group , for example N, N, N ', N'-tetraacetylethylenediamine (TAED), glucose pentaacetate (GPA), xylose tetraacetate (TAX), sodium 4-benzoyloxybenzenesulfonate (SBOBS), sodium trimethylhexanoyloxybenzenesulfonate (STHOBS), tetraacetylglucoluril (TAGU), tetraacetylcyanoic acid (TACA) , Di-N-acetyldimethylglyoxime (ADMG) and 1-phenyl-3-acetylhydantoin (PAH). The granules of the invention may contain one or more of these bleach activators.

The amount of bleach activator based on the finished, dry granules is at least 50, preferably 70 to 98, in particular 80 to 95 wt .-%.

Suitable binders are cellulose and starch and their ethers or esters, for example carboxymethylcellulose (CMC), methylcellulose (MC) or hydroxyethylcellulose (HEC) and the corresponding starch derivatives or mixtures thereof. The amount of binder, also based on the finished granules, can be from 1 to 45, preferably from 3 to 10,% by weight.

The mixing of the two powdery components bleach activator and binder can be carried out in conventional, batchwise or continuously operating mixing devices, which are generally equipped with rotating mixing devices, for example in a plowshare mixer. Depending on the effectiveness of the mixing device, the mixing times for a homogeneous mixture are generally between 30 seconds and 5 minutes.

Subsequently, this mixture is moistened with an aqueous solution of one or more polymers at temperatures of about 20 to 80 ° C. As polymers here are all types of organic polymers in question, as far as they are water-soluble. Particularly suitable polymers are polyacrylic acid, polymaleic acid or copolymers of acrylic acid and maleic acid in partially or completely neutralized form. The amount of water-soluble polymers and their concentration in the aqueous solution is such that the proportion of the polymer in the finished granules 1 to 5 wt .-% and the water content of the mixture in the granulation about 10 to 30, preferably 15 to 20 wt .-% is.

This mixture is then granulated, preferably in the same aggregate in which the components were previously mixed.

The water content of the granules thus obtained is then reduced to less than 2, preferably less than 1 percent by weight. The removal of the excess water can be done by drying under heat, the temperature of the granules expediently does not exceed 100 ° C and is below the melting temperature of the bleach activator. Suitable are dryers that do not adversely affect the granular structure of the product, for example, horde, vacuum or fluidized bed dryer.

From the dried granules, the coarse grain and fine grain content is separated by sieving. The coarse grain fraction is crushed by grinding and put back into the dryer. The fine grain content is returned to the mixer and granulated again. The grain size of the granules produced in this way is generally in the range of 100 to 2000 microns, preferably 300 to 1800 microns. The bulk density is in the range of 450 to 600 g / l.

An increase in the bulk density can be achieved by compressing the granules into larger agglomerates, for example in Walzenkompaktoren, and then crushed by means of mills, toothed disc rollers and / or Passiersieben to the desired particle size. The resulting granules have bulk densities of above 600 g / l.

The resulting granules according to the invention are suitable directly for use in detergents and cleaners. In a particularly preferred form of use, however, they can be provided with a coating shell according to methods known per se. For this purpose, the granules are coated in an additional step with a film-forming substance, whereby the product properties can be significantly influenced.

Suitable coating agents are all film-forming substances, such as waxes, silicones, fatty acids, soaps, anionic surfactants, nonionic surfactants, cationic surfactants, and anionic and cationic polymers.

Preference is given to using coating substances having a melting point of 30-100 ° C. Examples thereof as well as a method of application are disclosed in EP-A-0 835 926 described. The application of the coating materials is usually carried out by spraying the molten or dissolved in a solvent coating materials. The coating material can be applied to the granulate core according to the invention in amounts of from 0 to 20% by weight, preferably from 1 to 10% by weight, based on the total weight.

By using these coating materials, i.a. the reaction kinetics are specifically influenced, in order to prevent interactions between the bleach activator and the enzyme system at the beginning of the washing process in this way. In addition, the storage stability can be further improved by suitable coating.

In addition, the granules of the invention may contain other suitable additives, such as anionic and nonionic surfactants, which contribute to a faster dissolution of the granules of the invention. Preferred anionic surfactants are alkali salts, ammonium salts, amine salts and salts of amino alcohols of the following compounds: alkyl sulfates, alkyl ether sulfates, alkyl amide sulfates and ether sulfates, alkylaryl polyether sulfates, monoglyceride sulfates, alkyl sulfonates, alkyl amide sulfonates, alkylaryl sulfonates, α-olefin sulfonates, alkyl sulfosuccinates, alkyl ether sulfosuccinates, alkyl amide sulfosuccinates, alkyl sulfoacetates, Alkyl polyglycerol carboxylates, alkyl phosphates, alkyl ether phosphates, alkyl sarcosinates, alkyl polypeptides, alkyl amido coppeptides, alkyl isethionates, alkyl taurates, alkyl polyglycol ether carboxylic acids or fatty acids such as oleic acid, ricinoleic acid, palmitic acid, stearic acid, coconut oil acid salt or hydrogenated coconut oil acid salts. The alkyl radical of all these compounds normally contains 8-32, preferably 8-22 C atoms.

Preferred nonionic surfactants are polyethoxylated, polypropoxylated or polyglycerolated ethers of fatty alcohols, polyethoxylated, polypropoxylated and polyglycerinated fatty acid esters, polyethoxylated esters of fatty acids and of sorbitol, polyethoxylated or polyglycerolated fatty amides.

Also suitable additives are substances that affect the pH during storage and application. These include organic carboxylic acids or their salts, such as citric acid in anhydrous or hydrated form, glycolic acid, succinic acid, maleic acid or lactic acid. In addition, additives which affect the bleaching ability, such as complexing agents and transition metal complexes, for example iron-, cobalt- or manganese-containing metal complexes as in EP-A-0 458 397 and EP-A-0 458 398 described.

Further possible additives are substances which react with the peroxycarboxylic acid released from the activator in the wash liquor to form reactive intermediates, such as dioxiranes or oxaziridines, and in this way can increase the reactivity. Corresponding compounds are correspondingly ketones and sulfonimines US-A-3 822 114 and EP-A-446 982 ,

The amount of the additive depends in particular on its nature. Thus, acidifying additives and organic catalysts to increase the performance of the peracid in amounts of 0 to 20 wt .-%, in particular in amounts of 1 to 10 wt .-%, based on the total weight, added, metal complexes in concentrations in the ppm range.

The granules according to the invention are distinguished by very good abrasion resistance and storage stability in powdered washing, cleaning and disinfectant formulations. They are ideal for use in heavy-duty detergents, stain salts, machine dishwashing detergents, powdered all-purpose cleaners and denture cleaners.

In these formulations, the granules of the invention are usually used in combination with a source of hydrogen peroxide. examples for this are Perborate monohydrate, perborate tetrahydrate, percarbonates and hydrogen peroxide adducts on urea or amine oxides.

In addition, the formulation according to the prior art may have other detergent ingredients, such as organic and inorganic builders and co-builders, surfactants, enzymes, brighteners and perfume.

The combination of the starch, cellulose, starch and cellulose derivatives used as binders with polymers which are readily soluble in water has led to a marked improvement in abrasion resistance, presumably due to the different binding mechanisms of the two classes of substances, which apparently synergistically increase. In the prior art, there is no indication of this advantageous behavior of the above binder combination.

In contrast to the granules according to EP-A-0 238 341 In the case of the activator granules according to the invention, no higher reaction kinetics in the sense of a disintegrant effect was observed. Such an explosive effect should also be avoided in a targeted manner, since it can lead to a deterioration of the granule strength even in the presence of increased humidity.

The readily water-soluble polymers according to the present invention are very readily water-soluble both at pH 7 and at pH 10. As a result, the polymers can be introduced into the granules via a solution phase, which enables the very fine and homogeneous mixture required for the synergistic reinforcement of the granule strength with the starch, cellulose, starch or cellulose derivatives used as binders.

The following examples are intended to illustrate the invention without limiting it thereto.

Manufacturing and application examples Example 1: Batch production

In a ploughshare mixer M5R, Lödige, 15 kg of a mixture of 95 wt .-% tetraacetylethylenediamine (TAED) and 5 wt .-% ^® Tylose CR 1500 G2 (carboxymethylcellulose) with a mixing tool speed of 90 rev / min over a period of Intensively mixed for 10 min.

Subsequently, 20% by weight, based on the total mixture, of an aqueous solution consisting of 10% by weight of ^® Sokalan CP 45 (partially neutralized copolymer of acrylic acid and maleic acid) was added to the powder premix in the same ploughshare mixer at a mixing tool speed of 90 rpm. and 90 wt .-% water, sprayed at room temperature over a period of 10 min and further mixed for 2 min and granulated.

The moist granules were then transferred to a fluidized bed dryer and dried with gas inlet temperatures of 100 ° C to a residual water content of 2%.

This gave 9.4 kg of granules with a particle size distribution of 200-1600 μm (yield: 60%), and 3.9 kg of fine fraction <200 μm (25%), which could be worked up by re-granulation, and 2.3 kg of coarse fraction> 1600 μm (15%). ), which was worked up by grinding. The granules with a particle size of 200-1600 μm have a bulk density of 480 g / l.

Example 2: Continuous Production

In a continuous ploughshare mixer KT-160, from Drais, tetraacetylethylenediamine (238 kg / h) and ^® Tylose CR 1500 G2 (12 kg / h) were introduced via gravimetric dosing systems and in the entry area at a mixing tool speed of 90 rpm and a blade speed homogeneously mixed at 2000 rpm. In the middle part of the mixer, 50 l / h of a solution consisting of 10% by weight of ^® Sokalan CP 45 and 90% by weight of water were pumped directly onto a rotating cutter head. The moist product was granulated in the back of the mixer, discharged into a fluidized bed dryer and dried there continuously with gas inlet temperatures of 100 ° C. After drying, the raw granules were sieved between 200 μm and 1600 μm. In this case, 70 wt .-% target grain (200 - 1600 microns), 20% coarse grain (> 1600 microns) and 10% Feinkom (<200 microns) were obtained. The bulk density of the target granules is 500 g / l.

Example 3: Subsequent compaction

10 kg of the target granules produced in Example 2 with a bulk density of 500 g / l were pressed on a roll compactor Pharmapaktor (Bepex (DE)) with a pressure of 50-60 kN to slugs, which then in a two-stage grinding, with Zahnwalzenwalzen (Fa. Alexanderwerk (DE)) and crushing in a Passiersieb (Frewitt (DE)) at a mesh size of 2000 microns, were crushed. 7.2 kg granules of the target grain size 200-1600 μm (yield: 72%), 1.7 kg fines fraction <200 μm (17%), which can be recycled by recompacting, and 1.1 kg coarse fraction> 1600 μm (11%) were obtained as crude granules. ), which can be worked up by re-grinding. The target grain granules obtained in this way has a bulk density of 640 g / l.

Example 4: Subsequent Coating

1.5 kg of the target granules produced in Example 2 were placed in a plowshare mixer M5R (Lödige) and sprayed with 170 g of an 80 ° C hot stearic acid melt with thorough mixing at a mixing tool speed of about 90 rpm. The contents of the mixer were heated to a temperature of 50 ° C. during the coating step by means of a heating jacket. The coating and annealing time was about 10 minutes.

Determination of the abrasion resistance of the granules (method of ball mill abrasion)

For three different granulates, the abrasion resistance was determined by the following method: The activator granules to be examined are first freed by means of a vibration sieving (2 min) of particle fractions> 1.6 mm and <0.4 mm. 50 +/- 0.01 g of the resulting granular material with particle sizes between 1.6 mm and 0.4 mm are placed in a cylindrical metal ball mill container with a diameter of 11.5 cm (top edge) and 10 cm in height. For this purpose, 8 steel balls are given with 20 mm diameter and a weight of 30.0 g. Subsequently, the granules are ground in the ball mill over a period of 5 min at 100 U / min. After grinding, the particle size fraction <0.4 mm is determined by vibration sieving (2 min) and set in percent for initial weighing in the ball mill. This value is used as a measure of Abrasion resistance defined. Low values mean good abrasion resistance, high values mean poor abrasion resistance. Activator granules abrasion I 30% II 30% III 15%

Activator granules I: 92% by weight TAED, 7% by weight Tylose CR 1500 G2, 1% by weight residual water content, preparation according to EP-A-0 037 026 (Comparison)

Activator granules II: 92% by weight TAED, 7% by weight Sokalan CP 45, 1% by weight residual water content (comparison)

Activator granules III: 92% by weight TAED, 5% by weight Tylose CR 1500 G2, 2% by weight Sokalan CP 45, 1% by weight residual water content (granules according to the invention according to Example 2)

Claims (6)

1. The use of bleach activator granules in detergents, bleaches, cleaners and disinfectants, wherein bleach activator granules are used which are obtained by mixing one or more bleach activators with one or more binders from the group consisting of cellulose and starch and their ethers and esters and 0% by weight of the total amount of one or more water-soluble polymers from the group consisting of polyacrylic acid, polymaleic acid and copolymers of acrylic acid and maleic acid in completely or partially neutralized form, spraying-on of water comprising 100% by weight of the total amount of the water-soluble polymer and subsequent granulation and drying to a water content of less than 2% by weight, the total amount of the water-soluble polymer being from 1 to 5% by weight.
2. The use as claimed in claim 1, wherein bleach activator granules are used which comprise one or more compounds from the group consisting of activated carboxylic esters, carboxylic anhydrides, lactones, acylals, oxamides, N-acylated amines, amides, lactams, acyloxybenzenesulfonates, acylated sugars and also nitriles and nitriles carrying a quaternary ammonium group as bleach activator.
3. The use as claimed in claim 1, wherein bleach activator granules comprising from 50 to 98% by weight of bleach activator, from 1 to 45% by weight of binder and from 1 to 5% by weight of water-soluble polymer are used.
4. The use as claimed in claim 1, wherein bleach activator granules comprising from 0 to 20% by weight of one or more additives are used.
5. The use as claimed in claim 1, wherein bleach activator granules are used which were subsequently compacted.
6. The use as claimed in claim 1, wherein bleach activator granules coated with a coating substance are used.