CZ30597A3 - Process for producing a detergent - Google Patents

Abstract

A process for the manufacture of detergent powders involving fluidising a particulate material comprising a neutralising agent, preferably in a fluid bed, contacting LAS acid with the fluidised material to effect neutralisation and optionally adding a flow aid to the material either prior, during or subsequent to the addition of LAS acid is disclosed.

Description

A method for producing powdered detergent compositions by spray drying is known. However, processes of this type have the common disadvantage that they are energy intensive and, therefore, the resulting product is expensive. At the same time, the products have the additional disadvantage of having a low bulk density of 350-600 g / l.

U.S. Pat. No. 4,304,062 (Henkel) describes the preparation of a granular detergent composition in which the anionic surfactant in acid form is neutralized with an aqueous base solution under high gas pressure in a granulating and drying apparatus. In this process, the basic stage is to dry the liquid, different from the wetting agent.

Methods using neutralization with simultaneous drying are known in the production of detergents, but powders of high bulk density are often obtained. Indian Patent Specification No. 166,307 (Hindustan Lever Ltd.) discloses the specific use of an internally recirculated fluidized bed, and it is reported that the use of a conventional fluidized bed provides an agglomerate sticky product.

DD 140 987 (VEB Waschmittelwerk) describes a continuous process for the production of detergents in the form of granules, in which liquid components such as nonionic surfactants or acidic anionic precursors are sprayed onto a powder builder, especially sodium tripolyphosphate STPP with a high phase II content to give a product with a bulk density of 530-580 g / l. However, the process is limited to the use of high phase II STPP.

GB 1 404 317 describes the preparation of a detergent composition in the form of a powder of low or medium bulk density by neutralization and simultaneous drying. The procedure is to mix the sulfonic acid with an excess of anhydrous sodium carbonate in the presence of sufficient water for the neutralization reaction, but the water should not be sufficient to wet the product to be free flowing. The process is carried out in a mixing device, for example a belt, planetary or jet device, in which the mixing is effected by a stream of air. In the mixer, the particulate detergent is simultaneously compressed, which can lead to an increase in bulk density.

It has now been found that the disadvantages of the prior art processes can be overcome by neutralizing the acidic wetting precursor in the fluidized bed to produce a low bulk density powder.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION The present invention provides a process for the preparation of a particulate detergent composition having a bulk density in the range of 350 to 650 g / l, the process comprising contacting a particulate material comprising a neutralizing agent and optionally a builder into a fluidizing zone in which it is contacted. a liquid anionic surfactant precursor to at least partially, preferably substantially complete neutralization of the acid precursor to form a particulate detergent composition comprising the neutralized precursor acid.

The fluidizing zone is preferably a fluidized bed.

Preferably, the low bulk density detergent composition is prepared by preparing a detergent composition having a low bulk density

i) introducing the builder and neutralizing particulate material into the fluidized bed, ii) introducing into the fluidized bed a linear alkylbenzene sulfonate, LAS in the acid form for a time sufficient to at least partially neutralize the acid and achieve the desired properties of the powdered material.

The invention also relates to a detergent composition which can be prepared by this process.

The process according to the invention can be carried out batchwise or continuously. Detergent means laundry detergent that can be mixed with other conventional materials, such as bleaches and enzymes, and optionally with a further detergent component, often referred to as an adjuvant, to form a complex laundry detergent composition.

Thus, the process of the invention consists in neutralizing the acidic anionic precursor precursor with a neutralizing agent in the fluidized bed, preferably substantially dry, so that the mixture still retains the particulate form during neutralization. The acid precursor is preferably added in such a way that it does not accumulate in the detergent composition in a non-neutralized form.

The neutralizing agent is preferably added in particulate form and consists of an alkaline inorganic material, preferably an alkali salt, suitable materials being, in particular, alkali metal carbonates and bicarbonates, for example sodium.

The neutralizing agent should be present in an amount sufficient to completely neutralize the acid precursor.

If desired, a stoichiometric excess of neutralizing agent may be added to ensure complete neutralization or if the agent has yet another function, for example, in the case of sodium carbonate, the builder function.

In addition to the anionic surfactant obtained by the neutralization step, other anionic surfactants, or nonionic, cationic, amphoteric or semipolar surfactants, surfactants containing both types of ions and mixtures thereof may also be added. Wetting agents of these types are generally described in the summary publication Surface active agents and detergents vol. I, Schwarz and Perry. If desired, a soap derived from saturated or unsaturated fatty acids containing 12 to 15 carbon atoms can also be used as the anionic surfactant.

The active detergent composition is present in the total composition in an amount of 5 to 40%, preferably 12 to 30% by weight.

The detergent composition according to the invention preferably also contains a builder which can be added together with and / or after the neutralizing agent. Preferably, it is added together with the neutralizing agent.

Any conventional builder such as sodium carbonate, zeolite, sodium tripolyphosphate SPTT, sodium citrate and / or high surface area calcite may be used for this purpose. One or a mixture thereof may be used.

The same substance, for example sodium carbonate, may be used as the builder and neutralizing agent, in which case sufficient of the substance must be used to fulfill both functions.

The builder is preferably present in an amount of 15 to 65%, preferably 15 to 50% by weight, based on the weight of the detergent composition.

The powdered material obtained has a low bulk density in the range of 350 to 650 or 450 to 650 g / l, for example about 500 g / l, and is thus a bulk density comparable to the bulk density of the spray drying compositions.

Optionally and preferably, powder flow enhancers may be added. These compositions may be mixed with a neutralizing agent or builder before or after addition to the acid precursor. It is particularly advantageous to add this substance before or after partial addition to the acid precursor, since this can significantly reduce the bulk density of the resulting powder.

The flow aid is added to an amount of 0.1-15%, preferably 0.5-5% by weight of the detergent composition.

Suitable materials for this use are, for example, crystalline or amorphous alkali metal silicates, calcite, diatomaceous line, silica, for example obtained by precipitation, magnesium sulfate and calcium carbonate, also obtained by precipitation, for example. It is also possible to use mixtures of these, preferably using commercially available formulations such as Dicamol.

The detergent composition may also contain a particulate filler, such as an inorganic salt such as sodium sulfate or sodium chloride. The filler may be present in an amount of 5 to 50% by weight of the composition.

Thus, the detergent composition of the present invention may contain an active laundry detergent, builder, and optionally a flow aid, filler and other ingredients usually added in minor amounts such as dyes, perfumes, fluorescent agents, bleaching agents or enzymes.

It has further been found that a substantial reduction in bulk density can be achieved by selecting starting materials with a certain particle size.

It is preferred to use particulate materials in which at most 5% by weight of the particles have a particle size greater than 250 µm. It is also preferred that at least 30% by weight of the particles have a particle diameter of less than 75 µm. Preferably, the particulate materials have an average particle diameter of less than 200 µm so as to obtain powders of particularly low bulk density.

If necessary, some water may be added to facilitate neutralization. Water may be added in an amount of 0.5 to 2% by weight, based on the weight of the resulting detergent composition. The water is preferably added before, during or alternately with the addition of the acid precursor.

Preferably, the particulate material is added to the fluidized bed and then the desired amount of LAS acid is added, preferably in the form of a spray from above onto the fluidized bed material. If a flow aid is used, it can be added to the starting material, but is preferably added after the addition of a portion of the LAS acid, since this results in a lower bulk density.

The fluidized bed is typically maintained at room temperature to 60 ° C. The air flow should be sufficient to maintain the turbulence, preferably in the range of 0.6-1 ms. Fluidization of the solid material is an essential feature of the process of the invention, since it facilitates neutralization and granulation while preventing particle sticking. Thus, the process according to the invention is different from conventional mixing processes in which the particles are brought into contact with each other and at the same time the pressure is applied to them, which can lead to an increase in the bulk density of the powder as well as to its deterioration.

The following examples are intended to illustrate the invention.

DETAILED DESCRIPTION OF THE INVENTION

Examples 1-19

A powder mix of builder and inorganic alkaline material (sodium carbonate is used for both functions in Examples 1-4) and fillers are placed in the fluidized bed and the fluidized bed is maintained by adjusting the air velocity above the minimum velocity required for fluidization. The temperature of the fluidized bed is maintained between room temperature and 60 ° C. Linear alkylbenzenesulfonic acid, LAS, is sprayed onto the powder mixture in the fluidized bed.

The relative amounts of the various components of the formulation composition are shown in Table 1.

Examples 1-3 show the effect of including a flow aid, in this case Dicamol, in the mixture at various processing stages. In Example 1, the composition was not added at all. In Example 2, the composition was added to the starting material prior to the addition of LAS acid.

In Example 3, the composition was added after adding 50% of the total amount of LAS acid. Example 4 shows an improvement that can be achieved with a very fine particulate material. The results are summarized in Table 1 below.

and means the dissolution rate thereof. Dicamol is added at the beginning of the procedure. Dicamol is added after adding 50% LAS.

Table 1

Ex.

Ex. Ex. Ex

3

LAS

Anhydrous sodium carbonate

Dicamol

Salt

Fine salt

BD g / 1 DFR m / s ^and ROD%

17

30

2 *

43

687 625

85.72 96.77

81.6 80.6

603

88.23

82.3

546

93.8

82.5

The dissolution rate of the powdered material was determined by adding the powder to 1 L of water to a concentration of 1.4% and, after stirring at 100 rpm, the conductivity of the solution was measured until a constant value was reached. The values obtained indicate the amount of powder dissolved after approximately 90 seconds.

Examples 2 and 3 demonstrate that the addition of a flow aid prior to or during the addition of LAS can substantially reduce the flow density of the composition.

In Examples 5 to 19, additional powder materials were prepared using the starting materials with different particle size distributions as described in Examples 1 to 4. The results are summarized in the following tables. Table 2 shows the particle size distribution.

Table 2

Properties of various starting materials

Distribution sizes of particles CaCO ₃ I Ua ₂ S0 ₄ Salt Fine salt STPP / Um and Vo weight > 500 1,8 0.12 1.78 1.00 0.94 500-250 0.06 0.60 80.40 1.26 1.40 250-150 6.52 21.90 14.80 10,02 6.86 150-100 26.20 55.14 2.88 21.80 24.88 100- 75 16.20 8.56 0.14 24.07 7.92 S · 75 47.14 13.68 - 36.83 58.00 Mean particle diameter / µm 92.7 138.2 360,30 112.5 85.7 BD g / l 508 1,347 1,070 997 649 DFR ml / sec - 83.33 142.85 - - The following tables 3 and 4 results are shown for powders containing the active ingredient folder in an amount of 17 to 31%. Anhydrous carbonate sodium and STPP had similar distribution

the particle sizes as shown in Table 2 and the formulations based on this system had a bulk density of about 500 g / l.

Table 3

Example 5 6 7 8 9 10 LAS% 17.0 20.0 23.0 23.7 25.0 27.1 Water% 6.8 6.0 4.8 6.0 4,5 5.1 STPP% 35.0 22.0 35.0 35.0 25.0 25.0 Anhydrous CaCO ^% 22.0 22.0 22.0 22.0 20.0 20.0 Fine salt% - 30.0 - - 16.0 15.0 Alk. silicate,% - - - - - 1.0 Bulk density, g / l 500 510 500 490 500 495 DFR ml / sec 100 ALIGN! 120 120 120 100 ALIGN! 88

Table 4

Example 11 12 13 14 15 Dec LAS% 28.5 28.7 29.13 29.6 31.1 Water% 4,5 6.7 6.2 7.4 6.8 STPP% 25.0 35.0 25.0 35.0 35.0 Anhydrous CaCO ^% 20.0 22.0 20.0 22.0 22.0 Fine salt% 16.0 - - - - At ₂ S0 ₄ % - - 16.0 - - Bulk density g / l 514 470 510 500 520 DFR ml / sec 120 100 ALIGN! 88 102 115

Table 5

Example 16 17 18 19 Dec LAS% 17.0 17.0 17.0 13.0 Soap% - - - 4.0 Anhydrous CaCO ^% 22.0 30.0 35.0 20.0 STPP% 35.0 - - 35.0 HSA calcite% - - 16.0 - Water% 6.8 3.5 3.0 4.0 BD g / l 500 530 480 500 DFR ml / sec 100 ALIGN! 100 ALIGN! 120 150

Table 5 lists materials based on various builder systems, in particular STPP, sodium carbonate and HSA calcite. Using sodium carbonate and STPP produced materials with a BD value of about 500 g / l, while using HSA calcite gave powders with a bulk density of less than 500 g / l. In addition, Example 19 also discloses a mixture of active ingredients containing 13% LAS and 4% soap, resulting in a bulk density of 500 g / l.

Claims (9)

A process for the preparation of a particulate detergent having a bulk density in the range of 350 to 650 g / l, characterized in that the particulate material formed by the neutralizing agent and optionally the builder is fed to a fluidization zone in which it is contacted with a liquid precursor % of an anionic surfactant to at least partially, preferably substantially complete neutralization of the acid precursor to form a particulate detergent composition comprising the neutralized precursor acid. 2. A process for the production of a particulate detergent having a bulk density in the range of 350 to 650 g / l, characterized in that i) introducing the builder and neutralizing particulate material into the fluidized bed, ii) introducing into the fluidized bed a linear alkylbenzene sulfonate in acid form for a time sufficient to at least partially neutralize the acid and achieve the desired properties of the powdered material. Method according to claim 1 or 2, characterized in that it comprises an alkaline inorganic material, preferably an alkali metal carbonate, as neutralizing agent. Method according to one of Claims 1 to 3, characterized in that at least one flow aid is added to the mixture in an amount of 0.1 to 15% by weight. Method according to one of Claims 1 to 4, characterized in that the weight-increasing agent is added after the partial addition of the acid precursor. Method according to one of Claims 1 to 4, characterized in that the flow aid is added before the acid precursor is added. Method according to any one of claims 1 to 6, characterized in that at least one compound from the group of dicamol, crystalline or amorphous alkali metal silicate, calcite, diatomaceous earth, precipitated silica or magnesium sulphate is used as the flow aid. Method according to any one of claims 1 to 7, characterized in that the neutralizing agent and the other particulate materials have a particle size distribution such that at most 5% of the particles have a diameter greater than 250 µm and at least 30% of the particles have a diameter less than 75 µm. / Um. A detergent or detergent component obtainable by a process according to any one of claims 1 to 8.