EP0297273B1 - Formstable alkaline detergent with low specific weight and a process for its production - Google Patents

Abstract

The cleaning agents consist of at least 2 to 50 % by weight of alkali metal phosphates, 2 to 50 % by weight of silicates, 1 to 60 % by weight of alkali metal hydroxides and/or alkali metal carbonates or bicarbonates and additionally contain 0.25 to 10 % by weight of phosphoric acid partial esters. <??>These cleaning agents are produced by initially preparing a foam of the phosphoric acid partial esters with water in the ratio of from 1 : 2 to 1 : 80 by weight, stirring vigorously. After the other components have been incorporated by stirring or kneading into the foam, the resulting mixture is converted into shaped articles which are left to set for 0.5 to 15 hours.

Description

The present invention relates to dimensionally stable and specifically light alkaline cleaning agents, consisting at least of 2 to 50% by weight of alkali phosphates, 2 to 50% by weight of silicates, 1 to 60% by weight of alkali metal hydroxides and / or alkali metal carbonates or bicarbonates, and a process for their preparation.

Since powder detergents are often very dusty products, which, because of their hygroscopic constituents, for example alkali hydroxides or alkali metal silicates, also tend to cake or clump, it has already been proposed to use detergent-type detergents for use on the dosing devices of milking machines and commercial dishwashers were obtained by pouring a homogeneous mass into molds. Either alkali silicate, alkali metal hydroxide, alkali metal triphosphate and an active chlorine-releasing compound are mixed with water to give a pourable, homogeneous mass (see EP-A-203 526); the pourable composition can also be free from alkali metal hydroxides (see US Pat. No. 4,690,770); or alkali silicate, alkali metal hydroxide, alkali metal triphosphate and an organic complexing agent are melted together at about 60 ° C. (cf. DE-A-3 519 353).

A disadvantage of the known melt-block-shaped cleaning agents is that they can only be used with special metering systems because of their poor solubility and because of their different stripping amounts. With direct dosing, for example in dishwashers, a melting block dissolves only incompletely in the time available, which inevitably leads to a reduced cleaning effect.

• a) man den Phosphorsäurepartialester mit Wasser in Gegenwart von gasabspaltenden Mitteln, z,B. Alkalihydrogencarbonaten, verschäumt;
• b) man die Formlinge durch Einfüllen der Mischung in Formen erhält;
• c) man die Formlinge durch Strangpressen der Mischung erhält;
• d) man die gepreßten Stränge in Stücke zerschneidet.

It is therefore an object of the present invention to provide a process for producing dimensionally stable and specifically lightly alkaline cleaning agents which consist at least of alkali metal phosphates, silicates, alkali metal hydroxides and / or alkali metal carbonates or bicarbonates as well as phosphoric acid partial esters, the resulting cleaning agents having a low density and Slightly disintegrate on contact with water. This is achieved according to the invention by foaming the phosphoric acid partial ester with water in a weight ratio of (1: 2) to (1:80), preferably from (1: 3.5) to (1:72), with intensive stirring, by the remaining components are incorporated into the foam with stirring and / or kneading, that the resulting mixture is processed into moldings and that the moldings are allowed to set for 0.5 to 15 hours. The method according to the invention can optionally also be further developed in that

• a) the phosphoric acid partial ester with water in the presence of gas-releasing agents, e.g. Alkali hydrogen carbonates, foamed;
• b) the moldings are obtained by pouring the mixture into molds;
• c) the moldings are obtained by extruding the mixture;
• d) the pressed strands are cut into pieces.

Polyphosphoric acids of various degrees of condensation can be used as phosphorylating agents for the preparation of the phosphoric acid partial esters used according to the invention; Suitable organic hydroxyl compounds are, for example, oligoglycol ethers of alcohols with 6 to 15 C atoms per molecule or corresponding technical mixtures of alcohols or of (alkyl) phenols with 6 to 15 C atoms per molecule, each with 2 to 12 ethylene oxide and / or propylene oxide units per molecule of the alkyl or (alkyl) aryl oligoglycol ether. Mixtures of monovalent organic hydroxyl compounds of the type described above with polyvalent organic hydroxyl compounds, for example according to the procedure according to DE-C-26 45 211, can also be used as organic hydroxyl components for the reaction with the phosphorylating agents.

The cleaning agent according to the invention can be used as alkali metal phosphates, for example monosodium dihydrogen monophosphate, disodium hydrogen monophosphate, trisodium monophosphate, monopotassium dihydrogen monophosphate, dipotassium hydrogen monophosphate, tripotassium monophosphate, disodium dihydrogen diphosphate, trisodium -diphosphate, Contain tetrasodium diphosphate, tetrapotassium diphosphate, pentasodium triphosphate, pentapotassium triphosphate or high molecular weight, water-soluble polyphosphates such as graphite salt.

The silicate according to the invention can contain sodium metasilicate, water glass solutions in the ratio Na₂O: SiO₂ = 1: 2.0 to 1: 3.5, layered silicates or zeolite A as silicates.

The cleaning agent according to the invention can contain sodium and / or potassium hydroxide (anhydrous or as a monohydrate) and sodium or potassium carbonate.

The cleaning agent according to the invention can further contain complexing agents such as phosphonates and / or sodium salts of ethylenediaminetetraacetic acid or nitrilotriacetic acid and / or complexing carboxylic acids such as citric acid or tartaric acid in amounts of 0.5 to 5% by weight.

Furthermore, the cleaning agent according to the invention can contain surfactants, for example fatty alcohol polyglycol ethers with 12 to 18 carbon atoms and 3 to 25 mol ethylene oxide, ethylenediamine-ethylene oxide-propylene oxide adducts, fatty alcohol-ethylene oxide-propylene oxide adducts or block polymers of propylene oxide and ethylene oxide.

Finally, 0.1 to 10% by weight of compounds which release active oxygen or active chlorine, such as perborates, persulfates, chlorinated isocyanuric acids or "chloramine T" (N-chloro-p-toluenesulfonamide sodium), can be present in the cleaning agent according to the invention.

In the production of the cleaning agents according to the invention, the foaming of the phosphoric acid partial esters doubles the volume. The volume can be increased by adding gas-releasing Funds are increased.

It is surprising that the cleaning agents according to the invention, even with a very small addition of a phosphoric acid partial ester without the use of further auxiliaries for stabilizing the foam or for thickening or dispersing the solids or as a setting accelerator, are stable detergent moldings which easily disintegrate when introduced into water. If these detergent moldings are placed in water, they immediately disintegrate into a coarse-grained mixture, which dissolves like a powder product.

It is also surprising that the incorporation of active chlorine-releasing compounds into the cleaning agents according to the invention is practically possible without loss of active chlorine, although generally substances with surfactant properties such as phosphoric acid partial esters or the water required for foaming cause rapid decomposition, for example of dichloroisocyanurates.

example 1

0.5 part by weight of phosphoric acid partial ester, 26.5 parts by weight of water and 8.5 parts by weight of sodium hydrogen carbonate were mixed homogeneously with a dissolver disk while stirring and processed to form a stable foam. 30.7 parts by weight of anhydrous sodium metasilicate, 7.7 parts by weight of hydrated pentasodium triphosphate and 26.1 parts by weight of non-hydrated pentasodium triphosphate (with 40% phase I content) were introduced into the foam and homogenized, with the temperature of the im Kneader mass was kept below 60 ° C. The moldable mass removed from the kneader hardened at room temperature after about 24 hours; if the mass is allowed to age at 60 to 80 ° C, its hardening is accelerated.
The density of the foamed mass was 0.78 kg / l immediately after its production.
If the phosphoric acid partial ester in the recipe is replaced by the same amount of water, the resulting mass has a density of 1.71 kg / l immediately after its preparation.

Example 2

A cleaning agent was made analogously to Example 1
2.5 parts by weight of phosphoric acid partial esters
28.0 parts by weight of water
31.5 parts by weight of sodium metasilicate, anhydrous
10.0 parts by weight of hydrated and
28.0 parts by weight of non-hydrated pentasodium triphosphate
made at 56 ° C.
The density of the foamed mass was 0.62 kg / l immediately after its production, and 0.525 kg / l after an aging period of 20 hours at 75 ° C. in a drying cabinet.
If the phosphoric acid partial ester in the recipe is replaced by the same amount of water, the mass has a density of 1.8 kg / l after aging for 20 hours at 75 ° C.

Example 3

A cleaning agent was made analogously to Example 1
0.5 part by weight of phosphoric acid partial ester
25.0 parts by weight of water
14.0 parts by weight sodium metasilicate, anhydrous
30.0 parts by weight of non-hydrated pentasodium triphosphate with approx. 40% phase I
20.0 parts by weight of hydrated pentasodium triphosphate
0.5 parts by weight of sodium ethylenediaminetetraacetic acid
10.0 parts by weight of sodium perborate tetrahydrate
made at 56 ° C.
The density of the foamed mass after drying for 20 hours at room temperature was 0.67 kg / l.
If the phosphoric acid partial ester in the recipe is replaced by the same amount of water, the mass has a density of 1.4 kg / l after drying for 20 hours at room temperature.

Example 4

A cleaning agent was made analogously to Example 1
5.0 parts by weight of phosphoric acid partial ester
17.0 parts by weight of water
5.0 parts by weight of sodium disilicate, anhydrous
50.0 parts by weight of pentasodium triphosphate
12.5 parts by weight of nitrilotriacetic acid sodium salt as a 40% aqueous solution
10.0 parts by weight of "chloramine T"
made at 56 ° C.
After aging (24 hours at room temperature), the density of the detergent moldings according to the invention was 1.17 kg / l.
If the phosphoric acid partial ester in the recipe is replaced by the same amount of water, moldings with a density of 1.46 kg / l are obtained after aging for 24 hours at room temperature.

Example 5

A cleaning agent was made analogously to Example 1
1 part by weight of phosphoric acid partial ester
10 parts by weight of water
30 parts by weight of sodium hydroxide
50 parts by weight of sodium metasilicate pentahydrate
5 parts by weight of Graham's salt
4 parts by weight of phosphonic acid (50% solution)
made at 56 ° C.
The density of the resulting detergent was 1.4 kg / l.
If the phosphoric acid partial ester in the recipe is replaced by the same amount of water, the agent has a density of 1.74 kg / l.

Example 6

A cleaning agent was made analogously to Example 1
0.5 part by weight of phosphoric acid partial ester
4.5 parts by weight of water
20.0 parts by weight of sodium hypochlorite solution
30.0 parts by weight of sodium hydroxide
24.0 parts by weight of layered silicate
26.0 parts by weight of pentasodium triphosphate
made at 58 ° C.
After 3 weeks of aging at room temperature, the density of the detergent tablets was 1.48 kg / l.
If the phosphoric acid partial ester is replaced by the same amount of water in the recipe, the moldings have a density of 1.92 kg / l after 3 weeks of storage at room temperature.

Example 7

A cleaning agent was made analogously to Example 1
1 part by weight of phosphoric acid partial ester
20 parts by weight of water
30 parts by weight of sodium hydroxide
40 parts by weight of layered silicate
5 parts by weight of sodium sulfate
4 parts by weight of phosphonic acid
made at 57 ° C.
After two weeks of storage at room temperature, the density of the detergent tablets was 1.36 kg / l.
If the phosphoric acid partial ester is replaced by the same amount of water in the recipe, the moldings have a density of 1.86 kg / l after two weeks of storage.

All detergents prepared according to Examples 1 to 7 disintegrated 0.5 to 2 minutes after they were added to water and quickly dissolved depending on the temperature of the water.

Claims (5)

1. A process for the preparation of a dimensionally stable alkaline cleansing agent of low density, which consists at least of
   2 to 50% by weight of alkali metal phosphates
   2 to 50% by weight of silicates
   1 to 60% by weight of alkali metal hydroxides and/or alkali metal carbonates or bicarbonates and
   0.25 to 10% by weight of phosphoric acid partial esters, which comprises foaming phosphoric acid partial esters with water in a weight ratio of (1:2) to (1:80), preferably (1:3.5) to (1:72), with vigorous stirring, incorporating the remaining components in the foam with stirring and/or kneading, converting the resulting mixture to moldings and allowing the moldings to set for 0.5 to 15 hours.
2. The process as claimed in claim 1, wherein phosphoric acid partial esters are foamed with water in the presence of alkali metal bicarbonates.
3. The process as claimed in claim 1 or 2, wherein the moldings are obtained by filling the mixture into molds.
4. The process as claimed in claim 1 or 2, wherein the moldings are obtained by extruding the mixture.
5. The process as claimed in claim 4, wherein the extruded strands are cut into pieces.