DD282361A7 - METHOD FOR PRODUCING AN INFRUITATION INHIBITOR - Google Patents

Abstract

The invention relates to a process for the preparation of a incrustation inhibitor based on sodium polyphosphate as a laundry additive, which has the task of preventing Haertebildnerablagerungen on the laundry and in the washing machine when using hard wash water. According to the invention, sodium polyphosphate is granulated using polypropylene oxide polyoxyethylenes, resulting in a synergistically higher lime binder concentration than that of the sum of the individual components. {Incrustation inhibitor; sodium polyphosphate; Washing additive; Haertebildnerablagerungen; Laundry; Washing machine; Hard water; Polypropylenoxidpolyoxyethylen; synergism; lime binding}

Description

Field of application of the invention

The invention relates to a process for the preparation of a incrustation inhibitor based on sodium polyphosphate, which serves as a washing additive for preventing hardener deposits on the laundry and in the washing machine when using hard waters.

Characteristic of the known solutions

Incrustation inhibitors in washing have the task of causing hardeners in the wash liquor in such a state and hold, from which they can not be deposited on the laundry and in the washing machine. This is also imperfectly achieved by the builder-containing (solid) detergents in harder waters, since deposits of hardness formers so even at a lower alkaline earth hardness than 3.6 mmol CaO / l (corresponding to about 20 ° German hardness) occur by the complexing ability of the detergent not is sufficient. Encrustation inhibitors are becoming more important as laundry additives due to the increasing market share of detergents with reduced phosphate builder content.

Thus, it is known to obtain significantly higher ash values of the laundry using detergents with aluminosilicates with zeolite structure as builders, and a reduction in detergency over phosphate-containing detergents is accepted, which has hitherto not been satisfactorily eliminated by the use of so-called co-builders could be.

As complexing agents with alkaline earths, especially the alkali metal salts of polyphosphoric acid, phosphonic acids, aminopolycarboxylic acids and polyhydroxycarboxylic acids are used industrially.

Outstanding complexing agents have remained the sodium polyphosphates (NaPO ₃ J _n with η => 7 to 24, since they have a very high alkaline earth binding capacity and have a very positive effect on the washing properties of most detergents, ie they promote detergency 24, however, remains largely reserved for the laundry additives, since they are very susceptible to hydrolysis and significantly lose effectiveness in the process of conventional detergent production.

Most commonly used phosphate builder in solid detergents is pentasodium triphosphate (n = 3), which, however, has a significantly lower calcium binding capacity compared to the abovementioned sodium polyphosphates.

The ecologically motivated reduction in the use of phosphates in detergents also extends to the laundry additives. For example, DE-OS 2,756,732 proposes the use of aluminosilicates in conjunction with sodium polyphosphate, in DE 3,120,744 sodium polyphosphate is completely dispensed with and alumosilicate is used in conjunction with significantly more than 5% by weight of aminopolycarboxylic acid and, in addition, hydroxycarboxylic acids. However, the phosphate-free product is ecologically even more questionable due to a high content of aminopolycarboxylic acids, such as tri-, tetra- and pentacetic acids, so that the sodium polyphosphates in the incrustation is no qualitatively adequate alternative and they are still of great interest.

Surprisingly, there is no indication in the literature as to how the alkaline earth binding capacity of the alkali metal polyphosphates in aqueous solution, measured as lime binding capacity in mg CaO / g, can be synergistically influenced, rather all proposals are based on the extensive preservation of lime binding capacity in granulation Crystalline flour accumulating hygroscopic sodium polyphosphates of chain length η> 7, which are very easily split hydrolytically under the conditions of granulation and post-treatment or terminally degraded via low-polymer phosphates 2u the orthophosphates with loss of lime binding capacity.

Commercially available encrustation inhibitors based on Oasis sodium polyphosphate are partially hydrolyzed as washing additives or offered accompanied by accompanying substances in order to reduce the hygroscopicity and maintain the flowability. Well-known water-soluble concomitants are alkali carbonates and sulfates, and water-insoluble synthetic and natural phyllosilicates.

The lime-binding and dispersing capacity of sodium polyphosphate-containing combinations has hitherto always been more or less, but in any case less than that of the sum of the individual components before granulation, after the granulation process.

Object of the invention

The aim of the invention is a process for the preparation of sodium polyphosphate-containing incrustation inhibitors with a reduced sodium polyphosphate content, without the consequent loss of lime binding capacity having to be replaced by a necessary use of other known complexing agents.

Explanation of the essence of the invention

The object of the invention is to develop a process for increasing the lime-binding capacity of sodium polyphosphates of the general formula (NaPO ₃ I _n , where η> 7 <24) containing incrustation inhibitors with granulation of the mixtures containing sodium polyphosphates.

According to the invention, the object is achieved in that sodium polyphosphates in the presence of polypropylene oxide polyoxyethylenes from polypropylene oxide of molecular weight from 1000 to 2500 with 10 to 80Ma .-% ethylene oxide groups whose cloud point is below 1CO ⁰ C, granulated and post-treated in the usual way. The proportion of Polypropylenoxidpolyoxyethylene is less than 20 wt .-% of sodium phosphate. It is expedient to introduce the polypropylene oxide polyoxyethylenes via the granulating liquid. However, since these form only low-viscosity solutions with relatively high amounts of water and high water content unfavorable in the granulation and drying on lime binding capacity of the polyphosphates, low viscosity emulsions of conveniently a low polymer polyethylene oxide containing concentrated solutions of Natriumnitrilotriacetat, sodium aminotrimethylene or Fettalkoholpolyoxyethylenethersulfat with Polypropylenoxidpolyoxyethylen at temperatures of 20 to 5OX used or the pure Polypropylonoxidpolyoxyethylene are sprayed at temperatures of 60 to 80 ° C.

In addition, the mixtures can be incorporated functional additives such as complexing agents which have an alkaline earth binding capacity, such as the alkali metal salts of aminopolycarboxylic acids, phosphonic acids, polyhydroxycarboxylic acids, furthermore alkali carbonates and sulfates, foam depressors, alkali metal silicates, perfuming, granulation.

Suitable Polypropylenoxidpolyoxyethylene whose Polypropylenoxidkomponente is an average molecular weight of 1,000 to 2500, and having different with a mean of 10 to 80mA Ethylenoxidgruppenanteil .-% bandwidth distributions, whereby preferably the cloud point of 100 ⁰ C does not exceed. It is surprising that significantly higher lime binding values are determined using even small proportions of the additive according to the invention of the polypropylene oxide polyoxyethylenes in admixture with sodium polyphosphates, than was to be expected. This also applies in the presence of other ionogenic and nonionic surfactants of complexing substances that do not show comparable synergism. The synergistic effect caused by the presence of the polypropylene oxide polyoxyethylanes is particularly positive for sodium polyphosphates in the middle chain length region.

The process of granulation does not necessarily require the subsequent application of rotary tube drying when oriented to low or no granulating liquid. However, the aftertreatment in an unheated rotary kiln, which serves to standardize the formation of granules, is advantageous. This process is promoted by increasing the temperature, so that throughput increases are possible.

High water content granulating liquids are known to require rapid drying at high air temperatures to effectively counteract the process of hydrolysis and are therefore to be avoided. The products obtained are readily pourable, do not tend to cake on storage and dissolve quickly and completely in water. The dissolution process is accelerated if, in addition to the Alkaüssizen the carbonic acid, an acid salt, eg. Disodium hydrogen diphosphate, to the sodium polyphosphate. The invention will be explained in more detail with reference to embodiments.

embodiments

On a granulating a crystal flour mixture of 60Ma.-Sodium polyphosphate (NaPO ₃ I _n with η> 7 <14 and a lime binding capacity (KBV) of 164.7mg CaO / g (Example 1 to 5 and 7 and 8) and 40Ma.- Sodium bicarbonate is granulated on a granulator plate using the granulating liquid mentioned in the table "Experimental settings" previously brought to a temperature mentioned in the same table, and the product is subjected to regranulation in the rotary kiln equipped with internals in the usual way, the rotary kiln being subjected to granulation Acceleration of the process is fed in countercurrent with heated air.

In Example 6, the sodium polyphosphate used has a chain length η> 7 <24 and a KBV of 192.6 mg CaO / g.

The determination of the KBV was carried out nephelometrically by titrating the aqueous solution of the specimen at a constant pH of 6.0 in the presence of sodium oxalate using a calcium chloride solution at a temperature of +20 ⁰ C until the first permanent turbidity.

The theoretical KBV was calculated as the sum of the KBV of the individual components, which had been determined according to the aforementioned method.

The comparison between the theoretical and the determined KBV results in the increase or loss, which is given as a percentage of the theoretical value. The comparison of the test results shows that only the polypropylene oxide polyoxyethylene (PO-EO) containing products have a higher KBV compared to the theoretical value.

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Test appointments:

(The composition of the granulating solution is given in% by mass)

granulated

lierkom test no.

component 12 3 4 5 6 7 8

I - 43.5 36 41 100 7.5 - 45

II - _. - - 19.5 -

III - 13 10 9,5 - 7,5 - 10

Va 100 43.5 - 67.2

Vb - 36 - - -

Vc ___ 30 --_-

Vd _______ 45

water - - - - - 75 33.3 100 - Processing temperature ("C) 75 30 45 40 55 22 40

amount used

(Ma-TeNe) 5 15 20 10 20 15 10 15

I = aqueous solution of trinatriunnitrilutriacetate 325 g / l

II = Fettalkoholpolyoxyethylenethersulfat aue fatty alcohol of chain length Ci ₂ to C "with 2 to 3 EO groups as a 28% aqueous solution.

III = low polymer polyoxyethylene of molecular mass 150 to 600

IV = Aminotrimethylenphosphonatlösung, prepared from 42 parts by mass of a 32% aqueous Aminotrimethylenphosphonsäurelösung and

58 parts by weight of a 30% sodium hydroxide solution

 Va = PO-EO of polypropylene oxide (PO) of molecular weight 1700 with 30% EO groups.

Cloud point 32 ⁰ C

 Vb = PO-EO from PO of molecular weight 2,000 with 20% EO groups.

Cloud point 26 ^C C

 Vc = PO-EO from PO of molar mass 2,000 with 40% EO groups.

Cloud point 6O ⁰ C

 Vd = PO-EO with PO of molecular weight 2300 with 80% EO groups.

Cloud point 98 ° C.

Test results:

1 2 3 Experiment no. 4 5 6 7 8th 105 115 118 110 117 115 106 115 Yield (parts by weight) 92 93.5 93.5 93.5 96 105 93 93 KBVtheor. " 107 107 107 101 93 113 89 103 KBV determines " +16.3 + 14.4 +11.2 +8.0 -3.2 +7.6 -3.2 + 12.9 KBV-growth (%)

1 KBV in mg CaO / g substance

The resulting products Nos. 1 to 4, 6, 8 were readily free-flowing and showed no tendency to cake. In experiments no. 5 and 7 had to be dried in a rotary kiln with hot air of 140 ⁰ C.

A proportion of water had a braking effect on the synergistic effect produced by the PO-EO content.

Without the presence of PO-EO, KBV gain is observed.

The practical effectiveness of synergistically influencing the KBV of sodium polyphosphate by the association with PO-EO was compared to a commercially available incrustation inhibitor, the sodium polyphosphate of the chain length, by comparative examination of the incrustation of metallic surfaces by hardness hardeners of water of alkaline earth hardness of 35 ° dH with up to 50 wash cycles η> 7 <24, and thereby determines which polyphosphate reduction achieves analogous incrustation inhibitor effects. The hardening agent deposits were tested on metallic, heated surfaces made of chromium-nickel steel (heating coils) with the following liquor concentrations under simulation of the washing process:

5 g / l standard detergent TGL10446 / 05 with 3g / l incrustation inhibitor

cycle fleet Together Deposits after No. reduction 50 wash cycles 1. Standard detergent 1133 mg = 100 without addition Second Standard detergent with commercially available incrustations inhibitor 52.5% P ₂ O ₆ content 80 mg = 7.0 Third Standard detergent with Experiment no. 1 (34.4% P ₂ O ₆ content) 79 mg = 6.9 4th Standard detergent with Experiment no. 2 (32.6% P ₂ O ₆ content) 87 mg = 7.7

By reducing the phosphate content by 18% in the product in experiment no. 1 (cycle No. 3) with 4.8% by weight PO-EO the same encrustation values as with the comparison product (cycle 2).

Claims (3)

1. A process for the preparation of a incrustation inhibitor based on sodium polyphosphate (NaPO ₃ ) with η> 7 <24, characterized in that sodium polyphosphate in the presence of 3 to 17Ma .-%, based on sodium polyphosphate, Polypropylenoxidpolyoxyethylenen of polypropylene oxide of molecular weight 1000 to 2500 with 10 to 80Ma .-% ethylene oxide groups whose cloud point does not exceed 100 ⁰ C, is granulated in a known manner. 2. The method according to item 1, characterized in that the Polypropylenoxidpolyoxyethylen is sprayed on its own or, in admixture with low polymer polyoxyethylene, aqueous solutions of Natriumnitrilotriacetat, Natriumaminotrimethylenphosphat and or or Fettalkoholpolyoxyethylenethersulfat at temperatures of 30 to 75 ° C on the solid mixture. 3. The method according to item 1, characterized in that sodium polyphosphate is granulated in admixture with solid additives.