SK14597A3 - A method for producing particulated detergent composition and detergent composition or its component made by this method - Google Patents

Abstract

Production method for particulate detergent mixture with bul k density in the range 350 to 650 g/l, comprises dosage of the pa rticulate material, which contains neutralizing agent and selecta ble detergent builder, into the fluidising zone, fluidising the m aterial, contacting the liquid acid precursor of the anionic surf ace active substance, with fluidised material to perform at least partial and preferably complete neutralization of the acid precu rsor and for production of detergent particles, which contain neu tralized acid precursor.

Description

A process for producing a particulate detergent composition and a detergent composition or component thereof produced by the process

Technical field

The invention relates to a detergent composition having a low bulk density (SH) and a process for its production by dry neutralization, and further contemplates the use of a fluidized bed for the manufacture of such detergent compositions.

BACKGROUND OF THE INVENTION

It is known in the art to obtain powders by a spray-drying method. However, such a spray drying method has the disadvantage that it is both capital and energy intensive and consequently the product obtained therefrom is expensive. At the same time, the obvious advantage of such a process is that these powders have a low bulk density of 350 to 600 g / l.

Henkel 4304062 discloses the production of a cleaning surfactant granulate in which the acid form of an anionic surfactant is neutralized by an aqueous alkaline solution under high gas pressure in a granulation and drying chamber. In this process, the essential step is to dry the non-surfactant liquid component using hot air.

The dry neutralization process for the preparation of detergent powders is known in the art, but often results in powders of high bulk density. Indian patent no. No. 166307 (Hindustan Lever Ltd.) relates to the specific use of an internally recirculating fluidized bed and mentions that the use of a conventional fluidized bed will result in a clumping and sticking process.

East German patent no. 140 987 (VEB Vaschmittelwerk) discloses a continuous process for the production of granular laundry and cleaning compositions wherein a liquid component such as nonionic surfactants or acidic anionic surfactant precursors is sprayed onto a powdered detergent building material, in particular sodium triphosphate

- 2 (STPP) having a high phase II content to give a product with a bulk density ranging from 530 to 580 g / L. However, the method of this East German patent is limited to use with STPP having a high phase II content.

GB 1404317 describes the preparation of a low or medium bulk density dispersible powder by a dry neutralization process. The sulfonic acid is mixed with excess calcined soda in the presence of enough water to initiate the neutralization reaction, but not enough to wet the resulting product, which is in the form of a free-flowing powder. The process is carried out in a mixer, for example a mixer with a belt mixer, a planetary mixer or an air transfer mixer. In the mixer, the particulate detergent material is subjected to compressive forces that can lead to an increase in bulk density.

We have now found that the disadvantages of the prior art can be overcome by neutralizing the acidic surfactant precursor in the fluidized bed, forming a powder having a low bulk density.

SUMMARY OF THE INVENTION

The present invention provides, in a first aspect, a method of producing a particulate detergent composition having a bulk density in the range of 350 to 650 g / L comprising dispensing a particulate material comprising a neutralizing agent and optionally a detergent builder into a fluidizing zone, fluidizing the material, contacting an anionic surfactant precursor, with the fluidized material to effect at least a partial, and preferably substantially complete, neutralization of the acid precursor and to cause the formation of detergent particles containing the neutralized acid precursor.

Preferably, the fluidized zone is provided by a fluidized bed.

According to a further aspect of the present invention there is provided a method of producing a particulate detergent composition having a low bulk density comprising:

i. introducing a particulate material comprising a detergent builder and a neutralizing agent into the fluidized bed;

ii. introducing a linear alkyl benzene sulfonate (LAS) acid into the layer for a time sufficient to effect at least partial neutralization of the acid and to achieve the desired powder properties.

The invention also provides a detergent composition obtainable by a process as defined in the claims.

The process can be carried out in either batch or continuous mode of operation as required. The term detergent composition as used herein includes a detergent material that can be mixed with other conventional materials, such as bleaches and enzymes, to form a complete product, as well as a detergent component often referred to as a supplement, which can be further processed to form a detergent material, which can then be mixed with other materials as desired.

In accordance with the present invention, the method takes into account dry neutralization of the acidic precursor of the anionic surfactant with the neutralizing agent by fluidizing the neutralizing agent; preferably, the process is carried out in a fluidized bed. The dry neutralization process corresponds to at least partially and preferably substantially complete neutralization of the acid precursor, the mixture remaining in particulate form. The addition of the acid precursor is suitably controlled so that it does not accumulate in the neutralized form in the detergent composition.

The neutralizing agent is suitably particulate and comprises an alkaline inorganic material, preferably an alkaline salt. Suitable materials include alkali metal carbonates and bicarbonates, for example their sodium salts.

The neutralizing agent is suitably present at a level sufficient to completely neutralize the acid precursor. If desired, a stoichiometric excess of the neutralizing agent may be used to ensure complete neutralization or to provide an alternative function, for example, as a detergent component in the case of sodium carbonate.

In addition to the anionic surfactant obtained by the neutralization step, other anionic surfactants or nonionic, cationic, zwitterionic, amphoteric or semipolar surfactants and mixtures thereof may be added at a suitable time. Suitable surfactants include those generally described in Schwartz and Perry's Surface Active Agents and Detergents Volume I. Thus, if desired, a soap derived from saturated or unsaturated fatty acids with carbon atoms may also be present as an anionic surfactant.

The detergent active is suitably present at a level of 5 to 40% by weight, preferably 12 to 30% by weight of the detergent composition.

Suitably, the detergent composition comprises a detergent builder. The detergent component may, if desired, be introduced with a neutralizing agent and / or added subsequently. Preferably, the detergent component is introduced with a neutralizing agent

Any conventional detergent component may be used; suitable components include sodium carbonate, zeolite, sodium triphosphate (STPP), sodium citrate and / or large surface calcite. The detergent ingredient may also consist of one of the above, individually or in combination with other detergent ingredients.

The detergent component and the neutralizing agent may be the same material, for example sodium carbonate, in which case enough material will be used for both functions.

The detergent component is suitably present at a level of 15 to 65% by weight and preferably 15 to 50% by weight of the detergent composition.

The detergent powder obtained according to the invention has a low bulk density in the range of 350 to 650 g / l, or 450 to 650 g / l, for example about 500 g / l, and is thus comparable to the bulk density obtained by the spray-drying method.

Optionally and preferably, a flow aid is incorporated into the mixture. The composition may be mixed with a neutralizing agent and, if present, with a detergent component prior to or subsequent to the partial or complete addition of the acid precursor. It is particularly advantageous that by providing the flow aid before or after the partial introduction of the acid precursor, a significant reduction in the bulk density of the final powder can be achieved.

The flow aid is suitably present in an amount of from 0.1 to 15% by weight of the detergent composition, and more preferably in an amount of from 0.5 to 5% by weight.

Suitable flowing agents include crystalline or amorphous alkali metal silicates, calcite, ifusium clay, silica, for example precipitated silica, magnesium sulfate, and calcium carbonate, for example precipitated calcium carbonate. Mixtures of these materials can be used if desired. In a preferred embodiment, the flow aid is Dicamol.

The compositions may also contain a particulate filler which suitably comprises an inorganic salt, for example sodium sulfate and sodium chloride. The filler may be present at a level of 5 to 50% by weight of the composition.

The detergent composition produced according to the invention suitably comprises a surfactant and a detergent component, and optionally one or more free flowing agents, a filler and other minor ingredients such as a colorant, a perfume, a fluorescent, a bleach, enzymes.

We have further found that a significant reduction in bulk density can be ensured by selecting raw materials having certain particle size characteristics.

Suitably, the particulate material (s) has a particle size distribution such that no more than 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 size below 75 µm. Suitably, the particulate material (s) has an average particle size below 200 µm to provide detergent powders having a particularly desirable low bulk density.

If desired, a controlled amount of water may be added to facilitate neutralization. Water may be added in amounts of 0.5 to 2% by weight of the final detergent composition. The addition of this water is suitably before or together or instead of the addition of an acid precursor.

The particulate material is suitably introduced into the fluidized bed and then the desired amount of LAS acid is introduced, preferably by spraying onto the material and preferably from above. If a flow aid is present, it may be introduced with the starting material. However, it is preferred that the flow aid is added after the partial introduction of a portion of the LAS acid in order to obtain a lower bulk density.

The fluidized bed suitably operates at a temperature from ambient temperature up to 60 ° C. The air flow is sufficient to cause fluidisation and is preferably in the range 0.6 to 1 m ^- ^. Fluidization of the solid material is an essential feature of the present invention as it facilitates neutralization and granulation while keeping the particles separate. This is in contrast to the mixing methods in which the particles are intentionally contacted and compressed, which can lead to higher powder bulk density and poorer powder properties.

DETAILED DESCRIPTION OF THE INVENTION

The invention is illustrated by the following non-limiting examples.

Examples 1 to 19

The powdered detergent component / inorganic alkaline material (in Examples 1-4, sodium carbonate represents both functions) and the filler were introduced into the fluidized bed and fluidized using the surface air velocity above the minimum fluidization velocity. The temperature of the fluidized bed was from ambient temperature to 60 ° C. Linear alkylbenzenesulfonic acid (LAS) was sprayed onto the powder mixture in the fluidized bed.

The relative amounts of the various components of the mixture have been varied and are shown in Table 1 below.

Examples 1 to 3 illustrate the effect of incorporating a free flowing agent (in this case Dicamol) into the mixture at various points in the process. In Example 1, a flow aid was not added to the material. In Example 2, the flow aid was added to the starting material prior to the introduction of the LAS acid. In Example 3, the flow aid was added after the introduction of 50% LAS acid. Example 4 illustrates the advantages obtained using a fine particulate material. The results are shown in Table 1 below.

Table 1

Example 1 Example 2 Example 3 Example 4 LAS 17 17 17 1 kal. soda 30 30 30 30 Dicam - 2 * 2 * * 2 * * salt 45 43 43 - Fine salt - - - 43 SH (g / l) 687 625 603 546 DFR (ml / sec) 85.72 96.77 88.23 93,8 ^and ROD (%) 81.6 80.6 82.3 82,5 -

^and dissolution rate * Dicamol added initially ** Dicamol added after 50% LAS

The dissolution rate of the powder was determined by adding the powder to 1 L of water to give a concentration of 1.4% by weight with stirring of 100 ΐ / / min. and measuring the conductivity of the solution until a constant reading was obtained. The figures refer to the level of powder dissolved after about 90 seconds.

Examples 2 and 3 illustrate that a significant decrease in bulk density can be achieved by the addition of a flow aid either before or subsequent to the introduction of a portion of the LAS acid.

Other powders, Examples 5 to 19, as detailed below in Tables 3 to 5, were prepared according to the method described for Examples 1 to 4, and different feedstock materials having different particle size distributions were used. Table 2 summarizes the particle size distribution for different materials.

Table 2

Properties of various raw materials distribution size kal.sóda Na ₂ CO ₃ Sol Fine sol STPP (Am) % by weight > 500 1.8 0.12 1.78 1.00 0.94 500-250 2.06 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 <75 47.14 13.68 - 36.83 58,00 average size particle (s) 92.7 138.2 360,30 112.5 85.7 SH, g / l 508 1347 1070 997 649 DFR, ml / sec netečie 83,33 142.85 netečie netečie

Table 3

Examples 5 6 7 8 9 10 LAS,% 17.0 20.0 23.0 23.7 25.0 27.1 Humidity,% 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 sludge,% 22.0 20.0 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, ral / sec 100 120 120 120 100 88

Table 4

Examples 11 12 13 14 15 LAS,% 28.5 28.7 29.13 29.6 31.1 Humidity,% 4.5 6.7 6.2 7.4 6.8 STPP,% 25.0 35.0 25.0 35.0 35.0 sludge,% 20.0 22.0 20.0 22.0 22.0 Fine sol,% 16.0 - - - - ' Na ₂ S0 ₄ ,% - - - - - Bulk density, g / l 500 510 500 490 500 DFR, ml / sec 100 120 120 120 100

Table 5

Examples 16 17 18 19 LAS,% 17.0 17.0 17.0 13.0 Soap, % - - - 4.0 sludge,% 22.0 30.0 35.0 20.0 STPP,% 35.0 - - 35.0 HSA Calcite,% - - 16.0 - Humidity,% 6.8 3.5 3.0 4.0 Bulk density, g / l 500 530 480 500 DFR, ml / sec 100 100 120 150

Tables 3 and 4 show results for STPP powders which contain the active ingredient in the range of 17 to 31% by weight. Calcined soda and STPP had similar particle size distributions as shown in Table 2, and formulations based on such detergent systems resulted in products with a bulk density close to 500 g / l. Table 5 shows powders based on various detergent systems, i. STPP, soda ash and HSA calcite. Both calcined soda and STPP formulations resulted in powders with a bulk density of about 500 g / l, while HSA calcite based formulations resulted in powders with a bulk density of less than 500 g / l. Example 19 relates to a mixed active system containing 13% by weight LAS AD and 4% by weight soap resulting in a powder with a bulk density of 500 g / l.

Claims (9)

PATENT CLAIMS A process for producing a particulate detergent composition having a bulk density in the range of 350 to 650 g / l, comprising feeding a particulate material comprising a neutralizing agent and optionally a detergent builder to the fluidizing zone, fluidizing the material, contacting the precursor an anionic surfactant, with the fluidized material to effect at least partial, and preferably substantially complete, neutralization of the acid precursor and to cause the formation of detergent particles containing the neutralized acid precursor. 2. A method for producing a particulate detergent composition having a bulk density in the range of 350 to 650 g / l, comprising: i. introducing a particulate material comprising a detergent builder and a neutralizing agent into the fluidized bed; ii. introducing a linear alkyl benzene sulfonate (LAS) acid into the layer for a time sufficient to effect at least partial neutralization of the acid and to achieve the desired powder properties. Method according to any one of the preceding claims, characterized in that the neutralizing agent comprises an alkaline inorganic material, preferably an alkali metal carbonate. A method according to any one of the preceding claims, characterized in that it comprises the step of adding one or more free flowing agents in an amount of from 0.1 to 15% by weight of the detergent composition. Method according to any one of the preceding claims, characterized in that the flow aid is added after the partial addition of the acid precursor. Method according to any one of the preceding claims, characterized in that the flow aid is added before the introduction of the acid precursor. The process according to any one of the preceding claims, characterized in that the flow aid is one or more of Dicamol, crystalline or amorphous alkali metal silicates, calcite, ifusium clay, precipitated silica, magnesium sulfate. The method according to any one of the preceding claims, characterized in that the neutralizing agent and other particulate materials have a particle size distribution such that no more than 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 size below 75 µm. A detergent composition or component of such a composition, characterized in that it is obtainable by a process according to any one of the preceding claims.