WO1990001535A1

WO1990001535A1 - Granular bleaching aid containing bleach activators

Info

Publication number: WO1990001535A1
Application number: PCT/EP1989/000867
Authority: WO
Inventors: Thomas Merz; Jörg Poethkow; Jochen Jacobs; Eduard Smulders
Original assignee: Henkel Kommanditgesellschaft Auf Aktien
Priority date: 1988-08-01
Filing date: 1989-07-24
Publication date: 1990-02-22
Also published as: DE3826092A1; EP0356700A1; EP0430986A1

Abstract

Granular bleaching aids containing bleach activators from the class of N-acyl and O-acyl compounds as well as water-soluble, film-forming polymers which act as granulating aids, also contain 2 to 15 wt.% of a polyvalent carboxylic acid, hydroxycarboxylic acid or ethercarboxylic acid with 3 to 6 carbon atoms per molecule as a stabilizer. To produce the aids, a homogeneous, dry, preliminary mixture containing the bleach activator, the acid and some or all of the polymer granulating aid is prepared. The mixture is then sprayed with water or an aqueous solution of the remaining granulating aid and granulated.

Description

GRANULAR BLEACHING AGENT CONTAINING BLEACHING ACTIVATORS

EP 0 037 026-B1 (US Pat. No. 4,372,868) discloses a process for the production of easily soluble granules which comprises 90 to 98% by weight. -% of a bleach activator contains. According to this process, the pulverulent bleach activator is homogeneously mixed with cellulose or starch ether or starch, which is also in powder form, and then sprayed with water or a dilute aqueous solution of the cellulose ether and granulated at the same time. The granules are then dried. Tetraacetylethylene diamine (TAED) is preferably used as the bleach activator and sodium carboxymethyl cellulose (CMC) is preferably used as the cellulose ether. The products are characterized by admixing - to persalt-containing - granular detergents with normal storage by good resistance and quick and complete solubility at medium washing temperatures (45 to 60 C).

Another manufacturing process is described in EP 0 070 474 (US 4,457,858). For this purpose, an aqueous slurry containing the bleach activator and the cellulose ether is spray-dried in a weight ratio of 97: 3 to 93: 7. The properties of the products are comparable to those according to EP 0 027 026.

A further production process is described in EP 0 075 818 (US Pat. No. 4,695,397), namely mixtures of bleach activator are compacted under pressure to form particles with a diameter of 0.5 to 3 mm without the use of water. It has been shown that the dissolution rate of the known granules at low washing temperatures, in particular in the range between 25 and 40 ° C., is still not completely satisfactory. This applies to an increased extent to compacted granules according to EP 0 075 818, which often disintegrate very slowly or incompletely at low washing temperatures. A dispersion aid must therefore be added to the mixtures, such as sodium tripolyphosphate, nitrilotriacetate, sodium sulfate or salts of polymeric or copolymeric carboxylic acids, such as polyacrylate or a copolymer of acrylic acid and maleic acid as Na salt. However, these additives also do not significantly improve the dispersing properties, which applies in particular to the (co) polymers. On the other hand, phosphates and nitrilotriacetate are often undesirable from an ecological point of view, while sodium sulfate is a fiber.

The invention described below leads to a significant improvement in the dispersing and solubility properties of the granules. At the same time, the storage of the granules in ^" mixtures with saline-containing washing powders is increased considerably. It is particularly advantageous that the substances used are completely harmless from an ecological point of view and, because of their sequestering properties, also increase the cleaning action of the detergents. On the other hand, the required amount of these auxiliaries so low that the active substance content of the agents is not or only slightly reduced, and this reduction in the bleach activator content is more than compensated for by the significantly improved shelf life.

The invention relates to granular bleaching aids containing bleach activators from the class of the N-acyl and O-acyl compounds and at least one pelletizing aid from the class of water-soluble, film-forming polymers, characterized by a content of 2 to 15% by weight of one polyvalent carboxylic acid, hydroxycarboxylic acid or ether carboxylic acid with 3 to 6 carbon atoms in the molecule.

Examples of such polyvalent carboxylic acids are malonic acid. Succinic acid, glutaric acid, adipic acid, maleic acid, malic acid, tartaric acid, citric acid, diglycolic acid and carboxymethyloxysuccinic acid. Preferred acids are citric acid and carboxymethyl succinic acid. Their proportion, based on the bleach activator granules, is preferably 4 to 12% by weight.

Polyvalent carboxylic acids containing amino groups, such as nitrotrolicylic acid, are unsuitable because they are oxidizable and reduce the bleaching activity.

The known N-acylated amines, diamines, amides, glycolurils, diketopiperazines, hydantoins as well as acylated polyols and acylated p-hydroxybenzoates or p-hydroxybenzenesulfonates are suitable as bleach activators. _ Preference is given to tetraacetylmethylene diamine, tetraacetylethylene diamine (TAED), Perrtaace yl glucose, hexanoyloxybenzenesulfonate, octanoyloxybenzenesulfonate and

Nonanoyi-oxybenzenesulfonate with linear or branched acyl residues, the sulfonate groups being in the form of the sodium salt. TAED is particularly preferred. The content of bleach activators in the granules is 80 to 96% by weight, preferably 85 to 94% by weight.

Water-soluble, film-forming polymers such as water-soluble cellulose ethers, water-soluble starch or water-soluble starch ethers and mixtures thereof are used as granulation aids. Examples of cellulose ethers are methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, methyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose, carboxymethyl cellulose (as the sodium salt) and methyl carboxymethyl cellulose (sodium salt). As a strength comes z. B. Martian starch or depolymerized starch into consideration. Suitable starch ethers are, for example, carboxymethyl starch, hydroxyethyl starch and methyl starch. Sodium carboxymethyicellulose (CMC) has proven particularly suitable from this group.

Also suitable are homopolymeric or copolymeric carboxylic acids, such as polyacrylic acid, polymethacrylic acid, polymaleic acid, copolymers of acrylic acid or methacrylic acid with maleic acid and of maleic acid with vinyl methyl ether, these polymeric acids being present as free acids or preferably as sodium salts. Preferred representatives of this group are sodium polyacrylate and sodium salts of acrylic acid-maleic acid copolymers with a weight ratio of acrylic acid: maleic acid of 10: 1 to 1: 1, preferably 7: 1 to 2: 1. These compounds generally have molecular weights of 3,000 to 150,000, preferably 5,000 to 100,000.

A third group of film-forming polymers are carbon chain polymers with nonionic hydrophilic groups or polyether groups. Examples of this are polyvinyl alcohol, tei (saponified Potyvinylacetat, Polyvϊnylpyrrolϊdon, polyacrylamide and polyethylene glycol ether.

Mixtures of film-forming polymers of the aforementioned groups are used, for. B. a mixture of CMC or methyl cellulose with polyacrylate or with an acrylic acid-maleic acid copolymer or mixtures of one of the last two polymers with polyethylene glycol ethers.

The granulation aid content of the granules is 0.3 to 5% by weight, preferably 0.5 to 3% by weight. Despite this reduced content of granule auxiliary vibrators compared to the information in EP-B 0 037 026, the agents according to the invention are distinguished by good grain stability and a further improved storage capacity. resistance in mixtures with detergents containing peroxides and washing alkalis.

The granules can contain small amounts of moisture, for example up to 3% by weight, preferably less than 2% by weight. -%, contain. In contrast to known granules, this water content is not critical, i. H . even a slightly increased water content does not lead to a significant reduction in shelf life. This proves to be particularly valuable if the agents are stored in unfavorable climatic conditions, such as high air humidity and elevated temperature.

The production can be carried out by means of conventional granulation processes and granulation devices. The procedure is preferably such that an intimate, dry mixture of the bleach activator and the polyvalent carboxylic acid is first prepared and sprayed with an aqueous solution of the granulating aid in a granulating device. The concentration of the aqueous solution may vary according to ^"viscosity ^2" to ^"20 ^* wt -.% DES contain granulating It -can also doing so, that first a dry mixture einschließ¬ al ler Lich components of the present in powder form or a granulation aid. It produces part of the same and then sprinkles it with water or an aqueous solution which contains the rest of the granulating aid in solution, and such a procedure is particularly recommended when the aqueous solutions of the granulating aid swell strongly and become so highly viscous that they become so can only be sprayed with difficulty and distributed in the mixture to be granulated, which can be the case, for example, if carboxymethyl cellulose is to be used as a granulating aid in a concentration of more than 1 to 2% by weight Introducing amounts of granulation aid would be in In these cases, comparatively large amounts of water are required, which would have to be removed by drying during the granulation or afterwards.

If the proportion of the granulation aid is in the range from 0.3 to 1.5% by weight, in particular 0.5 to 1% by weight, the first-mentioned mode of operation, i. H . the introduction of the granulating aid as an aqueous solution is preferred.

During the granulation, additives such as dyes or color pigments can also be mixed in or introduced via the aqueous granulation liquid. Even small amounts of further, oxidation-stable complexing agents and stabilizers for per compounds can be mixed in this process step. Examples of these are salts of polyphosphonic acids, such as 1-hydroxyethane-1,1-diphosphonate, ethylenediamine tetramethylene phosphonate and diethylenetriamine pentamethylene phosphonate, each in the form of the sodium salt. The proportion of these additives can be up to 2% by weight, generally up to 0.5% by weight. related to the granules.

The water content of the granules is then reduced to less than 3, preferably less than 2 and in particular less than 1.5% by weight. The excess water can be removed by drying with the addition of heat, the temperature of the granules expediently not exceeding 80 ° C. and being below the melting temperature of the bleach activator and the carboxylic acid. - Dryers that do not adversely change the granular structure of the product are suitable, for example tray, vacuum or fluidized bed dryers.

It is also possible to use it in detergents or. to add granules to certain granules in washing processes during the granulation process which are usually very small amounts are added to the detergents separately in a special mixing process. These additives are those which are inactivated or lost in conventional detergent preparation, in particular in hot spray drying, such as foam inhibitors and fragrances. Suitable foam inhibitors are customary known defoamers, preferably polysiloxanes, and mixtures thereof with microfine silica. Examples of this are polydimethylsiloxane with a content of approx. 1 to 10% by weight, preferably 2 to 4% by weight, based on the finished granulate. Mixing in of the defoamer can already be done in the 1st Mix stage follow; however, the defoamer can also be dispersed in the granulating liquid which, in order to avoid demixing processes, should contain part of the granulating auxiliary in this case.

The granules produced in the manner indicated have a favorable grain spectrum. Possibly existing coarse and fine fractions can be sieved and returned to the process after grinding the coarse fractions. The granules are easy to pour, non-adhesive and are characterized by superior storage stability. Even at low washing temperatures, for example those of 25 to 40 ° C, they disintegrate very quickly and completely, so that the full bleaching power is fully available within a short time even under such washing conditions. They can be used with advantage in detergents, bleaches, oxidizers and disinfectants and retain their good properties even when mixed with the active ingredients contained in these agents. Examples

example 1

Tetraacetylethylenediamine (TAED) with an average grain size of 0.01 to 0.8 mm was used as the bleach activator. The grain size between 0.8 and 1.6 mm was 5% by weight, the proportion below 0.01 mm was 10% by weight. The abbreviation GT used in the following stands for parts by weight. 88.1 pbw of the powdery bleach activator were dry mixed with 10.4 pbw of citric acid (particle size 0.05 to 0.5 mm) in a horizontally rotatable mixer equipped with mixing and chopping tools attached to a rotating shaft . Over the course of 4 minutes, 10 parts by weight of sodium polyacrylate (MW = 10000) in 10% by weight aqueous solution were sprayed onto the homogeneous, constantly kept mixture. The granulation process was then continued for 1 minute. The still moist granules were dried in a fluidized bed dryer with air at 50 ° C. to a water content of 1% by weight. The content of the granules was thus

88.1 wt% TAED

10.4% by weight citric acid 0.5% by weight polyacrylate 1.0% by weight water. 92% by weight of the granules had a grain size of -0.1 to 1.2 mm. The rest was coarse and very fine, which were screened off.

To test the storage stability, 1.7% by weight (corresponding to 1.5% by weight of TAED) of the granules were mixed with 98.3% by weight of a commercially available, phosphate-reduced granular detergent containing 21.5% by weight Sodium perborate tetrahydrate, intimately mixed. Each 400 g of the powder mixture were stored in conventional printed cardboard packaging and filled in an internal climatic cell at 30 ° C. and 80 ° relative atmospheric humidity.

The determination of the solution properties and bleaching activity was carried out under practical conditions in a household washing machine in the presence of clean test laundry (the latter in order to avoid uncontrollable influences of individual soiling). In accordance with the metering instructions, 1.5 measuring beakers were filled into the dispenser and the washing process started. A first sample was taken at an alkali temperature of 30 ° C. After reaching the final temperature of 40 C, further samples were taken at intervals and the peracid content was determined analytically.

For comparison, products according to a) EP 0 037 026, example! 1 b) EP 0 075 818, Example 3 (W3) was used, the content of TAED in the mixture likewise being set to 1.5% by weight in both experiments.

The following results were achieved ^** :

Laαerstability

Example 1 Comparison a Comparison b

Beginning 100% 99% ι υei -Ö 4 weeks 100% 87% 94% 8 weeks 96 79% 92% Bleaching activity

Alkali temperature Example Comparison a Comparison b

55%

78%

95%

100%

Claims

-π -P claims

1. Granular bleaching aids containing bleach activators from the class of the N-acyl and O-acyl compounds and at least one pelletizing aid from the class of water-soluble, film-forming polymers, characterized by a content of 2 to 15% by weight of a polyvalent Carboxylic acid, hydroxycarboxylic acid or ether carboxylic acid with 3 to 6 carbon atoms in the molecule.

2. Composition according to claim 1, characterized in that the carboxylic acid consists of citric acid.

3. Composition according to claims 1 or 2, characterized in that the carboxylic acid content is 4 to 12 wt .-%.

4. Composition according to one or more of the preceding claims, characterized in that the bleach activator consists of tetra-acetylethylenediamine and is present in proportions of 80 to 96% by weight.

5. Composition according to one or more of the preceding claims, characterized in that the granulating aid consists of sodium carboxymethyl cellulose, polyacrylic acid or a copolymer of polyacrylic acid with maleic acid in a ratio of 10: 1 to 1: 1 or their sodium salts.

6. Composition according to claim 5, characterized in that the proportion of the granulating aid is 0.3 to 5% by weight.

7. Composition according to one or more of claims 1 to 6, characterized in that their water content is less than 3 wt .-%, preferably less than .2 wt .-%.

8. A process for the preparation of the agent according to one or more of claims 1 to 7, characterized in that a homogeneous dry mixture of the bleach activator and the polyvalent carboxylic acid is sprayed with an aqueous solution of the granulating aid and granulated.

9. A process for the preparation of the agent according to one or more of claims 1 to 7, characterized in that a dry mixture is prepared which contains the bleach activator, the carbonic acid and a part or the total amount of the granulating auxiliary, after which the Sprayed mixture with water or an aqueous solution of the remaining amount of the granulating aid and granulated.

1 O. A method according to claim 8 or 9, characterized in that a dye or pigment is added.