EP0061599A1 - Granule of alkali metal aluminium silicate and pentasodium tripolyphosphate, and process for its preparation - Google Patents

Abstract

The disclosure relates to a granulate with a particle size essentially of about 0.2 to 2 mm consisting of (a) about 2 to 95 weight % of a partially or completely hydrated pentasodium tripolyphosphate, (b) less than 3 weight % of an ammonium polyphosphate and the balance (c) being in the form of a water-insoluble aluminum silicate ion exchanging material. The granulate can be used in detergents.

Description

Alkaline aluminum silicates, especially crystalline or amorphous zeolites, are becoming increasingly important as detergent builders. However, these builders only reach in combination with other complexing agents for divalent cations such as Pentasodium triphosphate, abbreviated to NTPP, optimal washing properties. Since alkali aluminum silicates are finely powdered, there is great interest in non-dusting, free-flowing granules which contain both alkali aluminum silicates and NTPP. These can then be dry-mixed with the other detergent components without the formation of dust, and hydrolysis of the triphosphate is also avoided.

Efforts have been made several times to granulate alkali aluminum silicates, especially zeolites, together with alkali polyphosphates. For example, DE-OS 27 14 604 describes a granulate consisting of ion-exchanging alkali aluminum silicate, a high polymer phosphate with a P ₂ 0 ₅ content of 64-69 and pentasodium triphosphate. The high polymer phosphate is added in the form of alkali salts and in an amount of at least 5% by weight, based on the alkali aluminum silicate used, in powder form to the granulation mixture. The mixture is then granulated in the presence of water. This method has the disadvantage that the water is bound by the NTPP so quickly that it is no longer able to dissolve enough polymer phosphate for better granulation. Therefore, either larger amounts of polymer phosphate and longer residence times are required, or more water has to be added, which means that the granules have to be subsequently dried at 50 ° C.

DE-OS 27.56 732 describes a granulate which also consists of alkali aluminum silicate and a partially or completely hydrated alkali polyphosphate. These granules are produced by spraying water in fine mists onto the powder mixture of the granulate components, with a maximum of 10% of the total amount of water being allowed to be added per minute, since otherwise too large granule particles are obtained in addition to a high dust content. This process therefore harbors the danger of producing granules with a very broad grain spectrum which still have to be sieved afterwards.

Furthermore, according to DE-OS 27 36 903 it is known to granulate zeolite particles with water and starch as a binder. Certain portions of NTPP can also be granulated. However, the use of starch or similar substances as binders means that a substance useless for the washing process is introduced into the granules.

Finally, DE-OS 28 22 231 describes granules of hydrated pentasodium triphosphate and water-insoluble aluminosilicate ion exchange material. This is also produced by spraying water onto the powder mixture, the total amount of water used being at least that required to achieve a minimum hydrate water content of about 10% by weight in sodium tripolyphosphate and a water content in the aluminosilicate ion exchange material of 1.8 to 13.5 mol water per mol aluminosilicate corresponds. The strength of the granulate particles obtained in this way can still be improved, as will be shown below with reference to the invention.

It has now been found that the disadvantages of the known granules and their production processes can be avoided if a dilute aqueous solution of an ammonium polyphosphate is used as the binder for granulating a water-insoluble aluminosilicate and pentasodium triphosphate.

• a) etwa 2 - 95 Gew% eines teilweise oder vollkommen hydratisierten Pentanatriumtriphosphates,
• b) weniger als 3 Gew% eines Ammoniumpolyphosphates der allgemeinen Formel (I)
  
  in welcher n einen ganzzahligen Durchschnittswert von 100 bis 1000, m eine ganze Zahl bis maximal n+2 bedeutet und m/n einenwert von etwa 1 darstellt und dem Rest
• c) in Form eines wasserunlöslichen Aluminiumsilikationenaustauschmaterials der allgemeinen Formel (II)
  
  in welcher Kat ein mit Calcium austauschbares Kation der Wertigkeit n, x eine Zahl von 0,7 - 1,5, Me gleich Bor oder Aluminium, y eine Zahl von 0,8 - 6 und z eine Zahl von 1,8 - 13,5 ist.

Thus, the subject matter of the invention relates to granules with a particle size of approximately approximately 0.2-2 mm, consisting of

• a) about 2-95% by weight of a partially or fully hydrated pentasodium triphosphate,
• b) less than 3% by weight of an ammonium polyphosphate of the general formula (I)
  
  in which n is an integer average value from 100 to 1000, m is an integer up to a maximum of n + 2 and m / n is a value of approximately 1 and the rest
• c) in the form of a water-insoluble aluminum silicate exchange material of the general formula (II)
  
  in which cat a cation exchangeable with calcium of the valence n, x a number from 0.7 to 1.5, Me is boron or aluminum, y a number from 0.8 to 6 and z a number from 1.8 to 13, 5 is.

According to a preferred granulate composition, the proportion of the partially or fully hydrated pentasodium triphosphate is 30-70% by weight and the proportion of the ammonium polyphosphate is 0.03 to 1.6% by weight. At least 10% by weight of the pentasodium triphosphate is present as hexahydrate and at least 30% by weight of the aluminum silicate is present as a hydrate with a maximum of 13.5 moles of water per mole of aluminum silicate.

To produce the granules according to the invention, spraying is preferably carried out on an intimate powdery mixture of about 1 to 99% by weight of an anhydrous or, if appropriate, at most 5% by weight water containing sodium tripolyphosphate and about 99 to 1% by weight of a powdery, anhydrous or optionally bound water-containing aluminosilicate ion exchange material general formula (Kat _{2 / n} O) _x · Me ₂ O _3. (SiO ₂ ) _y , in which Kat, Me, x and y have the meaning given, with vigorous mixing, an aqueous 0.5-20% by weight solution of an ammonium polyphosphate of the general formula I in a fine mist and granulates the mixture with partial or complete hydration of the pentasodium triphosphate or the aluminosilicate ion exchange material.

The powdery mixture can consist of 30 to 70% by weight of the sodium tripolyphosphate and 70 to 30% by weight of the aluminum silicate, the latter for example a zeolite of the formula Na ₂ 0. Al ₂ O ₃ . (SiO ₂ ) ₂ . Can be 4.5 H ₂ 0.

It has further proved to be advantageous if at least 1 _0% by weight of the pentasodium triphosphate as hexahydrate and at least 30% by weight of the aluminosilicate be present as a hydrate having at most 13.5 mols water per mol aluminosilicate in the finished granulate. The mixture is generally sprayed with an aqueous 1-10% by weight solution of ammonium polyphosphate.

• Als Natriumtriphosphat kann sowohl ein feingemahlenes Produkt, das beispielsweise maximal 2 % einer Kornfraktion über 0,4 mm besitzt, als auch ein gröberes Produkt, dessen Anteil >0,15 mm mindestens 70 % beträgt, eingesetzt werden. Die Verteilung der Modifikationen I und II im NTPP ist variabel, jedoch werden schneller hydratisierende Typen mit einem Gehalt an Modifikation I von 20 - 60 % mit Vorteil eingesetzt.

In particular, the following should be noted regarding the method of the invention:

• Sodium triphosphate can be either a finely ground product, which has, for example, a maximum of 2% of a grain fraction larger than 0.4 mm, or a coarser product, the proportion of which> 0.15 mm is at least 70%. The distribution of Modifications I and II in NTPP is variable, but faster hydrating types with a Modification I content of 20 - 60% are used with advantage.

Products of the aforementioned formula composition are to be used as the aluminosilicate ion exchange material. Preference is given to zeolites, such as zeolite A. Because of their use as detergent builder liegensie in very finely divided form, for example having an average particle diameter of 3 - 5 _/ to before.

The P ₂ 0 ₅ content of the ammonium polyphosphate used for the granulation is more than 69%, polyphosphates with a P ₂ 0 ₅ content of over 71% being preferred.

The process according to the invention can be carried out, for example, by first mixing the pentasodium phosphate with the aluminosilicate material in a mixer and then spraying the aqueous ammonium polyphosphate solution onto the mixture via a nozzle. The spraying can also be carried out, for example, in a rotary tube or on a granulating plate onto the premixed material. It is important to ensure that no more granulating liquid is sprayed on than is necessary for the complete hydration of the sodium triphosphate contained in the mixture. A granulate produced in this way is not dusty, abrasion-resistant and stable in storage. It meets the requirements for further processing in detergents by dry admixing.

example 1

67.5 kg of anhydrous pentasodium triphosphate with a phase I content of 50% and the following particle size distribution were placed in a free-fall mixer: _> 1.6 mm = 0.7%,> 0.8 mm = 3.8%,> 0.4 mm = 20.5%,> 0.2 mm = 67.8% and> 0.1 mm = 88.2% and 67.5 kg of a zeolite (Zeolite A) with a loss on ignition of 19.8% and a grain size distribution of 99% <15 _/ um, 96% <10 µm and 3% <1 µm, mixed for 20 min. Thereafter, 9 l of an 8% by weight aqueous solution of ammonium polyphosphate - hereinafter called APP - with an average chain length of about ₄₀₀ and a P ₂ O ₅ content of 72.4% over the course of 3.5 hours with constant further mixing sprayed on. A mixed granulate of pentasodium triphosphate and the zeolite was obtained, which had the following properties:

Example 2

The procedure was analogous to Example 1, but 4 1 APP solution were sprayed on in 30 min. The mixed granules obtained from pentasodium triphosphate and the zeolite had the following properties:

Example 3

The procedure was as in Example 1, but using a 4% aqueous APP solution. The mixed granules obtained from sodium triphosphate and zeolite had the following properties:

Example 4

The procedure was as in Example 1, but using a sodium triphosphate with the following properties as the starting product: loss on ignition: 1.0% by weight; Phase I content: 26%; Grain size distribution:> 0.4 mm = 0.1;> 0.2 mm = 3.8%;> 0.1 mm = 25.0%;> 0.05 mm = 36.8%. In addition, a 4% by weight aqueous solution of an ammonium polyphosphate with an average chain length of 270 and a P ₂ 0 ₅ content of 72.4% was used. The resulting mixed granules of sodium triphosphate and the zeolite had the following properties:

Example 5

20 kg of a mixture of 50% by weight sodium triphosphate with the properties mentioned in Example 4 and 50% by weight of a zeolite with a loss on ignition of 1.0% by weight with 4 l APP solution according to Example 1 were placed on a granulating plate with a diameter of 1 m sprayed. A mixed granulate of sodium triphosphate and the zeolite was obtained with the following properties:

Claims (9)

1) Granules with a particle size of substantially about 0.2-2 mm, consisting of a) about 2-95% by weight of a partially or fully hydrated pentasodium triphosphate, b) less than 3% by weight of an ammonium polyphosphate of the general formula (I)

in which n is an integer average value from 100 to 1000, m is an integer up to a maximum of n + 2 and m _{/ n is} a value of approximately 1 and the rest c) in the form of a water-insoluble aluminum silicate exchange material of the general formula (II)

in which cat a cation exchangeable with calcium of the valence n, x a number from 0.7 to 1.5, Me is boron or aluminum, y a number from 0.8 to 6 and z a number from 1.8 to 13, 5 is. 2) Granules according to claim 1, characterized in that the proportion of the partially or fully hydrated pentasodium triphosphate is 30-70% by weight. 3) Granules according to claim 1 or 2, characterized in that the proportion of ammonium polyphosphate is 0.03 to 1.6% by weight. 4) Granules according to claims 1-3, characterized in that at least 10% by weight of the pentasodium triphosphate is present as hexahydrate and at least 30% by weight of the aluminum silicate is present as a hydrate with at most 13.5 moles of water per mole of aluminum silicate. 5) Process for the preparation of granules according to one of claims 1-4, characterized in that an intimate powdery mixture of about 1 to 99% by weight of an anhydrous or optionally containing at most 5% by weight of water sodium tripolyphosphate and about 99 to 1% by weight a powdery, anhydrous or optionally bound water-containing aluminosilicon ion exchange material of the general formula (Kat _{2 / n} O) x.Me ₂ O _3. (SiO ₂ ) _y , in which Kat, Me, x, n and y have the meaning given below intensive mixing, spraying an aqueous 0.5-20% strength by weight solution of an ammonium polyphosphate of the general formula I in a fine mist and granulating the mixture with partial or complete hydration of the pentasodium triphosphate or the alumosilication exchange material. 6) Method according to claim 5, characterized in that the powdery mixture consists of 30 to 70% by weight of the sodium tripolyphosphate and 70 to 30% by weight of the aluminosilicate. 7) Method according to claim 5 or 6, characterized in that the aluminosilicate ion exchange material are zeolites of the formula Na ₂ O.Al ₂ O ₃ · (SiO ₂ ) ₂ · 4.5 H ₂ 0. 8) Process according to claim 5-7, characterized in that the amount of water required for granulation is measured such that in the finished granulate at least 10% by weight of pentasodium triphosphate as hexahydrate and at least 30% by weight of the aluminosilicate as hydrate with a maximum of 13.5 mol water are present per mole of aluminosilicate. 9) Method according to claim 5-8, characterized in that the mixture is sprayed with an aqueous 1-10% by weight solution of ammonium polyphosphate.