MXPA99011512A - Production of detergent granulates - Google Patents

Abstract

A process of forming granular detergent products is effected in a gas fluidisation granulator. A fluidised particulate solid material is contacted with a spray of liquid binder. The excess velocity (Ue) of fluidisation gas relative to the mass or volume flux of the spray (a) or (b) when determined at the normalised nozzle-to-bed distance (D0) is set so that the flux number (FNm or FNv) as determined by (i) or (ii) (where&rgr;p is the particle density) is at a critical value of at least 2 for at least 30%of the process. Fine particulates may be extracted during granulation and re-introduced to the process to act as a flow aid or layering agent.

Description

PRODUCTION OF GRANULATED DETERGENTS DESCRIPTION OF THE INVENTION The present invention relates to a process for the production of granular detergent compositions. The technique for obtaining detergent powders by spray drying has been known for some time. However, the sprinkling process requires capital and energy and consequently the resulting product is very expensive. More recently, there has been much interest in the production of granular detergent products through processes that mainly employ mixing, without the use of spray drying. These mixing techniques can offer great flexibility to produce powders of several different compositions of a plant by post-dosing of several components after an initial granulation step. A known type of mixing process, which does not involve spray drying, employs a moderate speed granulator (a common example is very often colloquially called "a plow grid"), optionally preceded by high speed mixing (a common example very often colloquially called "a recycler" due to its cooling system by recycling). Typical examples of the process are described in European Patent Specifications Nos. EP-A367 339, EP-A-390 251 and EP-A 420 317. These moderate-speed and high-speed mixers exert relatively high levels of cutting in materials that they are being processed. An alternative type of mixer is a low speed cut-off mixer or granulator, a particular example is a fluidizing gas type granulator. In this type of apparatus, a gas (usually air) is made to blow through a body of particulate solids onto which a liquid component is sprayed. A fluidization gas granulator is sometimes called a "fluidized bed" granulator or mixer. However, this is not strictly accurate since the granulators can be operated with such a high gas flow velocity that a conventional fluidized bed is not formed. Although fluidizing gas granulators can give good volume density control, there is still a need for greater flexibility and, in particular, to produce lower volume density powders. The processes that involve fluidization gas granulation are very varied. For example, WO 96/04359 (Uni 1 e ve r) describes a process in which low volume density powders are prepared by contacting a neutralizing agent such as an alkaline builder and a liquid acid precursor of an agent. anionic surfactant in a fluidization zone to form detergent granules. German Patent No. 140 987 (VEB Wa s chmi tte 1 erk) describes a continuous process for the production of granular cleaning and washing compositions, wherein the liquid nonionic surfactants or the acid precursors of the anionic surfactants are sprayed on a fluidized powder improver material, especially sodium tripolyphosphate (STPP) having a high phase II content to obtain a product with a volume density ranging from 530-580 g / 1. The fluidization gas granulation apparatus basically comprises a chamber in which a gas stream, usually air, is used to produce a turbulent flow of particulate solids to form a "cloud" of the solids and in the liquid binder is sprayed on or inside the cloud to make contact with the individual particles. As the process progresses, the individual particles of the materials that start to become solid agglomerate, due to the liquid binder, to form granules. Watano et al. (Chem. Pharm. Bull., 1995, Vol. 43 (no. 7), Part I-IV, pp. 1212-1230) describes ^ a series of studies related to the progressive increase of granulation in a fluidized bed apparatus. The effects of the increase in several properties of the granule of a formulation Pharmaceuticals were tested on a number of process factors including spray conditions, drying efficiency, air flow rate, rotational speed agitator and shear angle and powder feed weight. All studies were related to a stirred fluidized bed system. Schaefer & Worts (Arch. Pharm. Chemi, Sci., 1977, Ed. 5, pp. 51 60) describes the effects of spray angle, nozzle height and initial materials on the size and distribution of the granule. None of the above techniques teaches how the control of the process variables, and in particular the liquid aspersion and the fluidizing gas, in relation to one another in a gas fluidization granulation system affects the properties in granulation. Although the gas fluidization granulators are good for granulating the detergent type product, it is very difficult to produce granulates in a range of desired volume densities, having an ideal particle size distribution and having good flow properties. 15 It has now been found that this can be achieved by controlling the movement of fluidized solids, which is a function of speed # ^^ of gas flow used to produce its fluidization, in relation to the speed of the application of the liquid binder. In particular, the present invention is based on the findings that the aforementioned objects can be achieved by controlling the product velocity of the excess velocity (Ue) of the fluidizing gas and the particle density (Pp) in relation to the flow mass (qmiiq) of the liquid is determined by a normalized distance (Do) of the liquid distribution device (which produces dew drops). In order to express this speed as a simple positive number, the applicants have found that it is convenient to indicate the aforementioned speed as the "flow number" (FNm) which is expressed as: According to the present invention, the spray mass flow (qmiiq) in D0 and the excess velocity (Ue) and the particle density (Pp) must be set such that FN is at a critical value of minus 2, during a greater proportion of the process. FNm is a number without dimension, as is the quantity PpUo / qmiiq itself. All the measurements used to calculate this number are in the units. ma sa kg speed - ms -i t i e po - s area -m .2 volmm "Particle density (Pp) can be determined as follows: - The particulate solids are placed in a hopper located 20 cm above a rectangular box of 300 ml internal volume. The hopper is conditioned with a horizontal metal slide so that the hopper can be filled before the solids fall into the box. The r e sba 1 adi 11 a - en t on ce s up and fill ^ _r the box beyond its capacity (that is, that is exceeded). The surface of the solids in the box is leveled by carefully removing the excess with the metal slipper at right angles to the surface of the solids and on the edge of the box, without exerting any compression action. Afterwards, the solids in the box are weighed. The heavy mass is divided by the internal volume of the box to give the volume density (BD) of the powder. 0 After: Pp - BD 1-dbed Where dbed is the porosity of the bed (not the porosity of the particle).

The value of dbed is determined by mercury porosimetry. As mentioned earlier in this specification, mercury porosimetry is not adequate to determine the porosity of small particles but is adequate to determine the porosity of a bed. The methodology for determining dbed by • the mercury technique is described in several standard texts. The liquid mass flow (qml? Q) can be determined from A where qmi? Q represents the mass flow of liquid (Qmiiq) by the contact area (A) of the unit measured at the distance D0 of the nozzle to the normalized bed. To determine Do first it is necessary to measure the height (HN) of the spray "nozzle" on the bottom of the fluidization chamber and determine the height of the bed (Hbed) under process operating conditions. In the case of a fluidized bed apparatus p e r s e, the height HN is the height of the nozzle above the bottom of the distribution plate separating the fluidization chamber and the gas distribution chamber. The amount Hbed is a parameter determined by solids. Of course, the spray may not be produced by a nozzle itself, but for the present purposes, the term "nozzle" is used to refer to the piece of apparatus from which the dew drops finally emanate before joining with the solid If the liquid is applied as a spray from discrete nozzles, then the contact areae.

(A) can be taken as the "footprint" area for each ? ^^ dew cone on the Ilbed; calculated for each nozzle. If a general "mist" sprinkler is used to wet the entire area of the fluidization chamber between (in Hbed) then the flow of total mass applied over all that area can be determined. It should be noted that it is preferred that the spray does not significantly wet the inner walls of the fluidization chamber, so that little or nothing of the liquid runs off into the interior of the chamber. you are walls. The value of UC / which is also necessary to calculate FNM is given by: - Ue = üs Umf The "superficial velocity" (Us) is measured as a gas velocity at a given gas supply velocity, without the solids present in the fluidization chamber. Preferably, Us is determined at the position in the fluidization chamber corresponding to the height of the bed (Hbe) • 5 The velocity of the gas at a minimum fluidization is measured as the minimum fluidization velocity (Umf), since it is the height from the bed to a minimum fluidization (Hmf). This can be done by adding solids to the fluidization chamber, which is not necessarily the case of the granulator, the gas flow initially is off. Afterwards, the gas flow increases gradually until the f 1 ui di z a l ion occurs. This is the minimum fluidization. It should be noted that in the current process according to the present invention, the degree of turbulence in the cloud of fluidized solids will be so high that a discernible "bed" will not form. However, that does not diminish the validity of determine a bed height (Hbed) • for the high gas flow rates used for such turbulent operation. In those cases in which a discernible bed is obvious, then Hbed can of course be measured directly. In all In the other cases (where turbulence inhibits the formation of an observable bed), the bed height can be calculated from the conventional equation: Hbed Hmf X I- e ubble where ebubb is a term that allows the volume fraction of the formation of bubbles and that is determined according to the standard texts., on fluidizing bed. However, in a very good approximation, where a discernible bed is not formed, Hbed can be calculated from: Hbed = 1.67 X Hmf Then, D0 = HN-Hbed with the condition that Do is 15 cm. or less, then D0 is taken as 15 cm. for purposes of determining the contact area (A). This is due to practical purposes, it has been found that the average penetration of the spray for a nozzle located under or within the solids cloud is approximately 15 cm.

A nozzle located inside or below the cloud of solids may not necessarily project the spray vertically up or down, but may also project it in any other direction. The contact area (A) is the area measured at a distance Do from the nozzle. The nozzle is removed from the granulator and oriented to point down to a height of C above a plane where the wetted area (A) is determined without taking into account the projection in the process itself. The contact area is the contact area wetted by the spray in a plane located in C below the nozzle. However, in many cases most of the spray can be found over a certain area with a penumbra where the degree of wetting is lower. The penumbra is not taken into account and the area A is determined as the area where 90% of the mass (or volume, as appropriate: see below) of the fallen liquid. In any case, it is preferred that the nozzle be such that the dew drops (at least within the aforementioned 90% moistened area) are substantially and homogeneously distributed. Finally, the process of the present invention requires that FNm be at least 2 during 30% of the process. Thus, a first aspect of the present invention now provides a process for forming a granular detergent product, the process comprises, in a gas fluidizing granulator, contacting a solid fluidized particulate material with a liquid binder spray, such that the product of the particle density (Pp) and the excess velocity (Ue) ) of the fluidizing gas in relation to the mass flow of the spray (qm? _. q) when it is determined at a distance from the nozzle to the normalized bed (Do) is set so that the flow number FNm is determined by: FNm = logio PpUa ^ mliq is at a critical value of at least 2 during at least 30% of the process. Currently, it should be noted that a very good approximation of FNm can be obtained by omitting the determination of Pp and using the volume flow (qvi? Q) instead of the mass flow (qmi? Q) • Then: Pliq A where qvliq represents the volume flow per contact unit area (A) (determined as described above), the volume flow of liquid is given by the liquid mass flow (Qmliq) divided by iiq which is the density of the liquid binder (P q). In this case: FNV = logí Uß * 3vliq Therefore, a second aspect of the present invention provides a process for forming a granular detergent product, the process comprising, in a gas fluidization granulator, contacting a fluidized solid particulate with a liquid binder spray, such that the excess velocity (Ue) of the fluidizing gas relative to the volume flow in the spray (qvi? q) is set so that the flow number (FNV) as determined by: is at a critical value of at least 2 during at least 30% of the process.

The gas fluidization granulator is typically operated at a surface air velocity (Us) of approximately 0.1-1.2 ms-1, either under negative or positive relative pressure and with an air inlet temperature varying from -10 ° or 5DC up to 80 ° C, or in some cases, up to 200 ° C. An internal operating temperature of room temperature up to 60 ° C is typical. Preferably, Us is at least 0.45 and more preferably at least 0.5 ms-1. Preferably, Us is in the range of 0.8-1.2 ms 1. It is preferred that the mass flow of the spray (cfmiiq) be at least 0.1 and more preferably up to at least 0.15 kgs ~ 1m "2. Preferably, the flow The mass of the spray is in the range of 0.20-1.5 kgs_1m ~ 2. If the process is a batch process, then FN must be at least 2 during at least 30% of the processing time (the reference to FN means FNm or FNV, as appropriate.) If the process is a continuous process, then FN must be at least 2 during at least 30% of the area of the bed on which the spray is carried out. It refers not only to any solid placed in the granulator at the beginning of the process but also to solids added to the middle of the process To determine FN during the middle of the process, it is therefore necessary to remove a sample of solids at the time or position (according to yes, respectively, it is a lot or a proc that continuous) and perform the determination of Umf, and Hbed in a separate way. The "process" in this context should be taken as the time or process area that occurs only while the liquid is being sprayed and excludes any part of the process where the spray is not being performed. The particulate solids on the basis of which FN is being determined could be discrete powder particles of one or more raw materials set at the beginning. However, in the middle of the process, the solids used to determine FN inequitably will be at least partially granular. On the other hand, as will be described in more detail below, even the particulate material placed at the beginning of the firing process may already be at least partially granulated. Although the critical value FN must be maintained for at least 30% of the process, it is preferably maintained for at least 50% or 70%, more preferably at least 75%, even more preferably at least 80%, still more preferably for at least 85%, more preferably at least 90% and 5 especially, at least 95% of the process. In the most idealized case, this critical value is maintained for substantially the entire process. On the other hand, whatever it is. the percentage of the process during which the value critical of FN (either 2 or higher) is maintained, ^ __ r it is preferred that FN is currently at least 2.3, more preferably at least 2.5, still more preferably at least 2.6 and more preferably at least 3. At higher values of FN, t i m e s / 1 on gi t ude s of processing become too long and in the end, the process becomes economically non-viable, although the products thus produced have very good quality. In this way, from the point of view of quality, FN should be as high as possible, but for economic reasons, FN is preferred not to be higher than 6, more preferably not higher than 5 and more preferably, not higher than 4.5.

In the context of the present invention, the term "granular detergent product" includes granulated finished products for sale, as well as granular or auxiliary components for forming finished products, for example, by post-dosing to, or with any other form of blending with additional or auxiliary components. In this way a granular detergent product as described herein may or may not contain detergent material such as a synthetic surfactant and / or soap. The minimum requirements are that it should contain at least one general type material of the conventional component of the granular detergent products, such as a surfactant (including soap), an improver, a bleach, a bleach system component, an enzyme, an enzyme stabilizer or a component of an enzyme stabilizer system, a soil anti-redeposition agent, a fluorescer or optical brightener, an anti-corrosion agent, an anti-foam material, perfume or colorant. As used herein, the term "powder" refers to materials that substantially consist of grains of individual materials and mixtures of such grains. The term "granule" refers to a small particle of agglomerated powder materials. The final product of the process according to the present invention consists of, or comprises a high percentage of granules. However, additional powder and granular materials may optionally be used in such a product. The initial solid materials of the present invention are in part and can • be powdery and / or granular. All references here to the average d3 / 2 of the initial solid materials refer to the average diameter d3 / 2 only of the solids immediately before they are added to the gas fluidization process. For example, it is described below as the granulator • gas fluidisation can be fed by at least partially solids p r e g r anu 1 a do s from a pr e-me z clador. It is very important to note that the "initial solid material" should be taken as including all the material of the first stage which sediments the gas fluidization granulation process but does not include all the The solids were dosed at p r e -me z c 1 a do r and / or live at any other processing stage until processing or after the end of processing in the gas fluidization granulator. For example, a layer-forming agent or a flow aid added after the granulation process in the fluidization granulator does not constitute an initial solid material. Whether the gas fluidization granulation process of the present invention is a batch process or a continuous process, the initial solid material can be introduced at any time during the time in which the liquid binder is being sprayed. In the simplest form of process, the initial solid material is first introduced to the gas fluidization granulator and then sprayed with the liquid binder. However, part of the initial liquid material may be introduced at the beginning of processing in the gas fluidization apparatus and the remainder may be introduced afterwards., either in one or more discrete batches or continuously. However, all solids fall within the definition of "initial solid material". The diameter d3.2 of the initial solid materials is obtained by the conventional laser diffraction technique (for example using a Helos Sympatec instrument). Suitably, the initial solid materials have a particle size distribution such that no more than 5% by weight of the particles have a particle size greater than 250 μ. It is also preferred that at least 30% by weight of the particles have a particle size below 100 μm, more preferably below 75 μm. However, the present invention can also be used with larger fractions of initial solid materials (ie >5% more than 250 μm, optionally also < 30% below 100 μm or 75 μm) but this increases the chance that some crystals of initial non-agglomerated materials will be found in the final product. This presents a benefit in terms of cost by allowing the use of cheaper raw materials. In any case, the initial solid materials have an average particle size below 500 μm to provide detergent powders having a particularly low desired volume density. Within the context of the initial solid materials, reference to an average particle size means the average particle diameter d3.2. Preferably, the average droplet diameter d3 2 of the liquid binder is not greater than 10 times, preferably not greater than 5 times, more preferably not greater than 2 times and more preferably not greater than the average particle diameter d3.2 of the fraction of total initial solid material which has a particle diameter d3 2 of from 20 μm to 200 μm, with the proviso that if more than 90% by weight of the initial solid materials has an average particle diameter d3.2 less than 2 0 μm then the average particle diameter of d3.2 of the total initial solid material should be taken as 20 μm and if more than 90% by weight of the initial solid material has an average particle diameter d3.2 greater than 200 μm then the diameter of average particle d3.2 of the total initial solid material should be taken as 200 μm. In practice, the nozzle chosen to achieve a given droplet size, when used in accordance with the instructions of the manufacturer of the gas fluidization granulator will predetermine the rate of liquid application and thus the degree of wetting in the moistened area. (TO) . Therefore, a third aspect of the present invention provides a process for forming a granular detergent product, the process comprising, in a gas fluidization granulator, contacting a solid fluidized particulate material with a liquid binder spray, such that during at least 30% of the process: (a) the excess gas velocity (Ue) is 0.1 to 1.0 ms -1, preferably 0.3 to 0.9 ms -1, more preferably 0.4 to 0.6 ms -1; (b) the average drop diameter d3 / 2 of the liquid binder is from 20 μm to 200 μm; and (c) the average droplet diameter d3 / 2 of the liquid binder is not greater than 10 times, preferably not greater than 5 times, more preferably not greater than - 2 times and more preferably not greater than the average particle diameter d3.2 of that fraction of the total initial solid material having a particle diameter d3,2 from 20 μm to 200 μm, with the proviso that more than 90% by weight of the initial solid material has an average particle diameter d3 / 2 lower at 20 μm then the average particle diameter d3.2 of the total initial solid material should be taken as 20 μm and if more than 90% by weight of the initial solid material has an average particle diameter d3,2 greater than 200 μm then the Average particle diameter d3.2 of the total initial solid material should be taken as 200 μm. The values (a) to (c) of the third aspect of the invention are maintained for at least 30% of the process preferably for any of the preferred, most preferred, etc. the percentages specified for the maintenance of the critical value of FN for the first and / or second aspect of the present invention. In the same way, these percentages should be taken as referring to the percentages of contact time (for a batch process, or contact area (for a continuous process) The average drop diameter d3.2 maximum is preferably 200 μm, for example 150 μm, more preferably 120 μm, still more preferably 100 μm and more preferably 80 μm On the other hand, the minimum drop diameter d3.2 is 20 μm, more preferably 30 μm and more preferably 40 μm It should be noted that when specifying any particular range preferred here, no average drop diameter d3.2 particular maximum is associated with any particular minimum d3 / 2 drop diameter.Thus, for example, a preferred range would be 150-20 μm, 150-30 μm, 150-40μm, 120-20μm , 120-30 μm etc. The average droplet diameter d3.2 is suitably measured, for example, using a laser phase Doppler anemometer or a laser light scattering instrument- (eg, that supplied by Malvern or Sympatec ) as it would be known by the experienced person The gas fluidization granulator can be adopted to recycle "fines" ie semi-granular or powder material of a very small particle size, so that they are returned to the inlet of the gas fluidization apparatus and / or to the pre-me zc 1 a do r. Such recycled fines can now be returned to the inlet or to any stage of the process, but especially towards the last part of the process in the gas fluidization granulator to act as a flow aid or a layer forming agent. This is discussed further below. Thus, a fourth aspect of the present invention now provides a process for forming a granular detergent product, the process comprising, in a gas fluidization granulator, contacting a fluidized solid particulate with a liquid binder spray, extract the fine particles during the granulation and reintroduce the fine particles to the process to act as a layer forming or auxiliary flow agent. Preferably, the fine particles are elutriated material, for example, they are present in the air leaving the gas flow chamber. These fines are preferably recycled during the operation of a continuous gas fluidization granulation process but can also be made as batches. It can optionally be stored before its re-production. The gas fluidization granulator can optionally be of the type provided with a bed with vibration, particularly for use in the continuous mode, in the case of a bed with vibration, the height HN is measured as the distance of the nozzle above the bottom of the distribution plate when the distribution plate is not vibrating. The equations of the present invention can be applied particularly to gas fluidization granulators that do not have a rotation and / or mechanical agitator.

In a preferred class of processes according to the present invention, the liquid binder comprises an acid precursor of an anionic surfactant and the fluidized particulate solids comprise an inorganic material. Such acid precursor may be for example the acid precursor of an anionic alkylbenzene sulfonate (LAS) or primary alkyl sulfonate (PAS) or any other type of anionic surfactant. Suitable materials that are used as the inorganic alkaline material include alkali metal carbonates and bicarbonates, eg, sodium salts thereof. The neutralizing agent is most preferably present at a level sufficient to completely neutralize the acidic component. If desired, a stoichiometric excess of neutralizing agent can be employed to ensure complete neutralization or provide an alternative function, for example, as a builder, for example if the neutralizing agent comprises sodium carbonate. The liquid binder may alternatively or additionally contain one or more other liquid materials such as liquid nonionic surfactants and / or organic solvents. The total amount of the acid precursor will normally be as high as possible, submitted to the presence of any other component in the liquid and subject to other considerations to which reference is made below. In this way, the acid precursor may constitute at least 98% (eg, at least 95%) by weight of the liquid binder, but may be at least 75%, at least 50% or at least 25% in weight of -binder. It can also, for example, constitute % less by weight of the binder. Of course, the acid precursor can be omitted, in its entirety if required. When the liquid non-ionic surfactant is present in the liquid binder together with an acidic precursor of an anionic surfactant, then the weight percentage of all acid precursors to the nonionic surfactants will normally be from 20: 1 to 1. :twenty. However, this ratio may be, for example, 15: 1 or less (of the anionic), 10: 1 or less, or 5: 1 or less. On the other hand, the nonionic may be the major component for the ratio to be 1: 5 or more (non-ionic), 1:10 or more or 1:15 or more. Proportions in the range of 5: 1 to 1: 5 are also possible. In order to manufacture granules containing anionic surfactants, it would sometimes be desirable not to incorporate all the anionics by neutralization of the acid precursor. Some may optionally be incorporated in the form of alkali metal salt, dissolved in a liquid binder or as part of the solids, in that case, the maximum amount of anionic incorporated in the salt form (expressed as a percentage by weight of the total anionic surfactant salt in the product result of the gas fluidization granulator) is preferably not more than 70%, - more preferably not more than 50% and more preferably not more than 40%. The granules, this can be achieved by incorporating a fatty acid, either in solution in the binder-liquid or as part of the solids.The solids in any case must also comprise an inorganic alkaline neutralizing agent to react with the fatty acid to produce the soap.

The liquid binder will most often be totally or substantially non-aqueous, ie, any amount of water present does not exceed 25% by weight of the liquid binder, but preferably not more than 10% by weight. However, if desired, a controlled amount of water may be added to facilitate neutralization. Typically, the water can be added in amounts of 0.5 to 2% by weight of the detergent product. Any amount of water is suitably added before or in alternation with the addition of the acid precursor. Alternatively, an aqueous liquid binder may be employed. This is especially suitable for manufacturing products which are auxiliary to subsequently mix with other components to form a fully formulated detergent product. Such auxiliaries usually, apart from the components resulting from the liquid binder, will mainly consist of one or a small number of components normally found in detergent compositions, for example a surfactant or an enhancer such as zeolite or sodium t-fat. However, this does not prevent the use of aqueous liquid binders for granulation if they are substantially and fully formulated products. In any case, typical aqueous liquid binders include aqueous solutions of alkali metal silicates, water-soluble and water-soluble acrylic polymers (e.g. Sokalan CP5) and the like. In a refinement of the process of the present invention, an initial solid material may come into contact and may be mixed with a first portion of the liquid binder, for example in a low, moderate or high speed cutting mixer (i.e., a pre-mixer). -me zc 1 ador) to form a partially granulated material. The latter can then be sprayed with a second portion of the liquid binder in the gas fluidization granulator, to form the granulated detergent product. The two-step granulation process is preferred, but not absolutely necessary, that the total liquid binder is dosed only in a pre-mixer of partial granulation and granulation steps. Conceivably, part could be dosed during or before the pre-mixing of partial granulation and / or fluidization. Also, the content of the liquid binder may vary between this first and second stage.

The extent of granulation in the premixer (ie, partial granulation) and the amount of granulation in the gas fluidization granulator is preferably determined according to the desired fine product density. The preferred amounts of the liquid binder to be dosed in each of the two steps can be varied in this way: (i) If a lower powder density is desired, ie 350-650 g / 1 (a), it is preferably added. -75% by weight of the total liquid binder in the premixer; and (b) the remaining 95-25% by weight of the total liquid binder is preferably added in the gas fluidization granulator. (ii) If a higher powder density is desired, ie 550-1300 g / 1 (a) preferably 75-95% by weight of the total liquid binder is added in the pre-mixer; and (b) the remaining 25-5% of the total liquid binder is preferably added in the gas fluidization granulator.

If an initial pre-mixer is used for partial granulation, an appropriate mixer for this step is a LodigeR CB high-speed cutting machine or a moderate speed mixer such as a LodigeR KM machine. Other suitable equipment includes the DraisR T160 series manufactured by Drais Werke GmbH, Germany; the Littleford mixer with internal cutting shears and a turbine type miller mixer that has several shears on one axis of rotation. A high or low speed cutting mix granulator has a mixing action or a cutting action which are operated independently from each other. The preferred types of high-speed cutting machines are mixers of the FukaeR FS-G series; DiosnaR V series ex Dierks & Sohne, Germany; Pharma Matrix® ex T. K. Fielder Ltd; England. Other mixers that are believed to be suitable for use in the process of the invention are FujiR VG-C series ex Fuji Sangyo Co., Japan; the RotoR ex Zanchella & Co. Srl, Italy and SchugiR Flexomix granulator. Still another mixer suitable for use in the production stage is the Lodige series (Registered Trademark) FM series (plow grinders) the batch mixer from Morton Machine Co. Ltd., Scotland. Optionally, a "layer forming agent" to a "flow aid" can be introduced at any appropriate stage. This is to improve the granularity of the product, for example avoiding the aggregation and / or the formation of plastics of the granules. Any cap a / aux 1 i a r flow forming agent is suitably present in the amount of 0.1 to 15% by weight of the granular product and more preferably 0.5 to 5%. The layer forming / auxiliary agent 1 i a r of flow may be in the form of peaks r e c r ed 1, according to the fourth aspect of the present invention. Suitable layer-forming agents or flow agents (whether or not introduced by recirculation) include amorphous or crystalline alkali metal silicates, aluminosilicates including zeolites, Dicamol, calcite, diatomaceous earths, silica, for example. precipitated silica, chlorides such as sodium chloride, sulfates such as magnesium sulfate, carbonates such as calcium carbonate, and phosphates such as "sodium tripolyphosphate phosphate." Mixtures of these materials can be used as desired.

In general, additional components can be included in the liquid binder or can be mixed with the solid neutralizing agent at the appropriate stage of the process. However, the solid components can be posited to the granular detergent product. In addition to any other anionic surfactant which optionally can be produced by a neutralization step, additional surfactants, or nonionic surfactants as mentioned above, also semi-polar or amphoteric surfactants, cationic ions and mixtures thereof are They can add at an appropriate time. In general, suitable surfactants include those generally described in "Surface active agents and detergents" Vol I by Schwartz and Perry. As mentioned above, if desired, soap derived from saturated or unsaturated fatty acids having, for example, an average of C 1 to C 2 carbon atoms may also be present. If present, the detergent active is suitably incorporated at a level of 5 to 40%, preferably 10 to 30% by weight of the granular detergent product.

A complete detergent composition very often contains a builder. Such an improver can be introduced with the solid material 1 and / or subsequently added as desired. The improver also constitutes a neutralizing agent, for example sodium carbonate, in which case sufficient material will be employed for both functions. Generally speaking, the total amount of builder in the granular product is suitably from 5 to 96%, preferably from 10 to 80%, more preferably from 15 to 65%, especially from 15 to 50% by weight. The inorganic builders that may be present include sodium carbonate, if desired in combination with a calcium carbonate crystallization outlet as described in GB-A-1 437 950. Any sodium carbonate will need to be in excess to neutralize the precursor anionic acid if the latter is added during the process. Other suitable improvers include amorphous and crystalline aluminosilicates, for example zeolites as described in GB-A 1 473 201; amorphous aluminosilicates as described in GB-A 1 473 202; and mixed amorphous / crystalline aluminosilicates as described in GB 1 470 250; and layer-forming silicates as described in EP-B-164 514. Inorganic phosphate builders, for example, sodium, orthophosphate, pyrophosphate and tripolyphosphate, may also be present, but for environmental reasons they are no longer preferred. The aluminosilicates, whether they are used as layer-forming agents and / or incorporated in the volume of the particles may be suitably present in a total amount of 10 to 60% and preferably in an amount of 15 to 50%. The zeolite used in most commercial particulate detergent compositions is zeolite A. Advantageously, however, the maximum aluminum P zeolite (zeolite MAP) described and claimed in EP-A-384 070 can also be used. The zeolite MAP is an alkaline metal at 1 umin or s i l of the type P having a silicon with a percentage of aluminum not exceeding 1.33, preferably not exceeding 1.15, and more preferably not exceeding 1.07. Organic buffers that may be present include polycarboxylate polymers such as polyacrylates, copolymers at low temperatures and acrylic phosphinates; monomeric polycarboxylates, such as citrates, gluconates, oxycodones, monohydric acid, di-glycerol, carboxymethyl oxycarbonates, carboxymethyl-1-oxalate, diphtheria, hi dr oxi et il imi nodi ace tat os, alkyl and alkenyl malonates and succinates; and sulfonated fatty acid salts. A copolymer of maleic acid, acrylic acid and vinyl acetate are especially preferred since they are biodegradable and thus environmentally desirable. This list is not intended to be exhaustive. Especially preferred organic builders are citrates, suitably used in amounts of 5 to 30%, preferably 10 to 25% by weight; and acrylic polymers, more especially copolymers of low and high grade, suitably used in the amount of 0.5 to 15%, preferably 1 to 10% by weight. Citrates can also be used at lower levels (eg, 0.1 to 5% by weight) for other purposes. The improver is preferably present in an alkali metal salt, especially in the sodium salt form.

Suitably, the enhancer system should also comprise a crystalline layer-forming silicate, for example, SKS-6 ex Hoechst, a zeolite, for example zeolite A and optionally an alkali metal citrate. The granular composition resulting from the process of the present invention may also comprise a particulate filler (or any other component which does not contribute to the washing process) which suitably comprises an inorganic salt, for example sodium sulfate and sodium chloride. The filler may be present at a level of 5 to 70% by weight of the granular product. The present invention also includes a granular detergent product resulting from the process of the invention (before any post dosification or the like). This product will have a volume density determined by the exact nature of the process. If the process does not involve pre-mixing to effect partial granulation, a final volume density of 350-750 g / 1 can be normally expected. As mentioned above, the use of a pre-mix allows the final volume density to be 350-650 g / 1 or 550-1300 g / 1, respectively, according to whether the option (i ) or (ii) is used. However, the granular detergent products resulting from the present invention are also characterized by their particle size traits. Preferably, no more than 10% by weight have a diameter >1.4 mm and more preferably, no more than 5% by weight of the granules are above this limit. It is also preferred that no more than 20% of the granules have a diameter of > 1 mm Finally, the granules can be distinguished from granules produced by other methods by mercury porosimetry. This last technique can not reliably determine the porosity of the individual non-agglomerated particles but can be used to characterize the granules. A fully formulated detergent composition produced in accordance with the invention may for example comprise the active detergent enhancer and optionally one or more flow aids, a filler and other minor ingredients such as color, perfume, fluorescer, bleaches, enzymes. The invention will now be illustrated by the following non-limiting examples.

The following formulation was produced Sodium-LAS 24% by weight Sodium carbonate 32% by weight STPP 32% by weight Zeoilite 4A 10% by weight Water 2% by weight In Examples I to IV, the Sparying Systems nozzle SUE 25 was used, operating at 5 bars of atomization pressure, while in example V, the same nozzle was operated at 2.5 bar of atomization pressure. In these examples, the rate of addition of the liquids to the solids varied, between 0.50 and 1.60 kgmin "1, as did the fluidization velocity, which varied from 0.9 to 1.1 ms.1 In Examples VI to VIII, a Spraying Systems VAU SUV 152 nozzle, where the speed of liquid addition to the solids was fixed at 2.0 kgmin "1. The height of the nozzle above the distributor silver varied between 0.50 and 0.80m under these operating conditions. The following values for the operating conditions and properties of the product have been obtained. The number FNm was calculated using the description given above.

? The n value of the Rosm Rammler distribution is calculated by setting the particle size distribution to a powder distribution n according to the following formula: n R = 100 Exp where R is the cumulative percentage of the powder over certain sizes D. Di is the average granule size (corresponding to RRd) and n is a measure of the particle size distribution. DS and n are the Rosin Rammler settings for a measured particle size distribution. A high value n means a distribution of narrow particle size and low values mean a wide particle size distribution.

Claims (21)

1. Process for forming a granular detergent product, the process comprises, in a gas fluidization granulator, contacting a fluidized solid particulate with the binder sprinkling, so that the product of the particle density (Pp. ) and the excess velocity (Ue) of the fluidizing gas relative to the mass flow of the spray (qmi iq) when determined at a distance '(Do) from nozzle to standardized bed is set so that the flow number FNm is determine by: FNm = logio PpUe which is at a critical value of at least 2 during at least 30% of the process.

2. Process for forming a granular detergent product, the process comprises, in a gas fluidization granulator, contacting a solid material in fluidized particles with the sprinkling of a liquefied binder, such that the excess velocity (Ue ) of the fluidizing gas in relation to the volume flow of the spray qv? That is fixed such that the flow number (FNV) as determined by F V = logio U, L ivllq is at a critical value of at least 2 during at least 30% of the process.

3. Process according to claim 1, wherein the mass flow of the spray (qmixq) is at least 0.1, more preferably at least 0.15, and more preferably in the range of 0.20-1.5 kgs ^ "2.

4. Process according to any of the preceding claims, wherein the surface air velocity (Us) is at least 0.45, more preferably at least 0.5, and more preferably is in the range of 0.8-1.2 ms-1.

5. Process according to any of the preceding claims, wherein the process is a batch process and the critical value of FN is maintained for at least 30% of the contact time.

6. Process according to any of claims 1 to 4, wherein the process is a continuous process and the critical value FN is maintained for at least 30% of the contact area.

7. Process according to any of the preceding claims, wherein the critical value FN must be maintained for at least 50% or 70%, preferably at least 75%, more preferably at least 80%, even more preferably i so less 85%, more preferably at least 90% and especially, at least 95% of the process.

8. Process according to any of the preceding claims, wherein the critical value of FN is at least 2.3, more preferably at least 2.5, still more preferably at least 2.6 and more preferably at least 3.09.

Process according to any of the preceding claims, wherein the critical value of FN is not greater than 6, preferably not greater than 5, and more preferably, not greater than 4.5.

10. Process according to any of the preceding claims, wherein the average droplet diameter d3.2 of the liquid binder is not greater than 10 times, preferably not greater than 5 times, more preferably not greater than 2 times and more preferably not greater than the average particle diameter d3 2 of that fraction of the total initial solid material which has a particle diameter from 20 μm to 200 μm, with the proviso that if more than 90% by weight of the initial solid material has an average particle diameter d3.2 less than 20 μm then the average particle diameter d3.2 of the total initial solid material should be taken as 20 μm and if more than 90% by weight of the initial solid material has an average particle diameter d3.2 greater than 200 μm then the average particle diameter d3,2 of the total initial solid material should be taken as 200 μm.

11. Process according to any of the preceding claims, wherein the minimum droplet diameter d3 / 2 is 20 μm, preferably 30 μm and more preferably 40 μm.

12. Process according to any preceding claim, wherein the diameter e drop average _d3 / 2 maximum is 200 μm, for example 150 μm, preferably 120 μm, more preferably 100 μm and more preferably 80 μm.

13. Process for forming a granular detergent product, the process comprises, in a gas fluidization granulator, contacting a solid fluidized particulate material with a liquid binder spraying, such that during at least 30% of the process: a) the excess gas velocity (Ue) is 0.1 to 1.0 ms ~, preferably 0.3 to 0.9 ms "1, more preferably 0.4 to 0.6 ms" 1; (b) the average drop diameter d3 / 2 of the liquid binder is from 20 μm to 250 μm; (c) the average drop diameter d3.2 of the liquid binder is not greater than 10 times, preferably not greater than 5 times, more preferably not greater than 2 times and more preferably not greater than the average particle diameter d3 / 2 of that fraction of the total initial solid material which has a particle diameter d3.2 of 20 μm to 200 μm, with the proviso that if more than 90% by weight of the initial solid material has an average particle diameter d3.2 less than 20 μm then the average particle diameter d3 / 2 of the total initial solid material should be taken at 20 μm and if more than 90% by weight of the initial solid material has an average particle diameter d3,2 greater than 200 μm then the diameter of Average particle d3.2 of the total initial solid material should be taken as 200 μm.

14. Process according to claim 13, wherein conditions (a), (b) and (c) are maintained for at least 50% or 70%, preferably at least 75%, most preferably at least 80% , even more preferably at least 5%, more preferably at least 90% and especially, at least 95% of the process.

15. Process according to any of the preceding claims, wherein the liquid binder comprises an acid precursor of an anionic surfactant and the particulate solids comprise an inorganic alkaline material.

16. Process according to any of the preceding claims, wherein a first portion of the liquid binder is mixed with an initial solid particulate material in a pre-mixer to form a partially granular solid material and then a second portion of the liquid binder is sprayed to make contact with the partially granular solid material in the gas fluidization granulator to effect complete granulation.

17. Process according to claim 16, wherein the granular detergent product has a volume density of 350 to 650 g / 1, wherein: (a) 5-75% by weight of the total binder is added to the pre-mixer; and (b) the remaining 95-25% by weight of the total liquid binder is added in the gas fluidization granulator.

18. Process according to the claim 16, wherein the granular detergent product has a bulk density of 550 to 1300 g / 1, wherein: (a) 75-95% by weight of the total liquid binder is added to the pre-mixer; and (b) the remaining 25-5% by weight of the total liquid binder is added in the gas fluidization granulator.

19. Process according to claim 18, wherein the granular detergent product has a bulk density of 350 to 650 g / 1, wherein: (a) 5-75% by weight of the total liquid binder is added to the pre-mixer; and (b) the remaining 95-25% by weight of the total liquid binder is added in the gas fluidization granulator.

20. Process according to the claim 18, wherein the granular detergent product has a bulk density of 550 to 1300 g / 1, eh where: (a) 75-95% by weight of the total liquid binder is added to the pre-mixer; and (b) the remaining 25-5% by weight of the total liquid binder is added in the gas fluidization granulator.

21. Granular detergent product produced by a process according to any of the preceding claims.