MXPA01003137A - Granular detergent compositions having homogenous particles and process for producing same - Google Patents

Abstract

A detergent composition which has improved solubility or dissolution in laundering solutions, especially in solutions kept at cold temperatures (i.e., less than about 30°C), is provided. The granular detergent composition is aesthetically pleasing to consumers and has improved flowability. The granular detergent composition has a homogeneity number of greater than 1 wherein the homogeneity number is defined by the equation HN=Xbulkr/Xpart. A process for producing the detergent is also provided.

Description

COMPOSITIONS GRANULATED DETERGENTS HAVING HOMOGENEOUS PARTICLES AND PROCEDURE TO PRODUCE THE SAME The present invention relates to improved granular detergent compositions of homogeneous particles having superior solubility, especially in cold temperature wash solutions (i.e., less than about 30 ° C), and excellent flowability.

BACKGROUND OF THE INVENTION Recently, there has been considerable interest within the detergent industry for laundry detergents that present comfort, good appearance and solubility of liquid laundry detergent products, in addition to maintaining the cleaning performance and cost of granular detergent products . However, the problems associated with the paste-granulated detergent compositions with respect to appearance, solubility and comfort for the user are formidable. Such problems have been exacerbated with the advent of low-dose or "compact" granular detergent products that typically do not dissolve in the wash solutions in the manner in which their liquid detergent laundry counterparts are dissolved. These low dosage detergents currently have a high demand, since they retain the benefits and can be sold in small packages that are more comfortable for consumers before using them, but with less comfort when supplied in the washing machine compared to laundry detergent liquid that can simply be poured directly from the container opposite to those that have to be measured with a measuring spoon from the box and then supplied in the washing solution. As mentioned, such low dosage or "compact" detergent products unfortunately experience dissolution problems, especially in solutions for low temperature washing (i.e., less than about 30 ° C). More specifically, inadequate dissolution results in the formation of "dough" that appears as solid white masses remaining in the washing machine or in laundry washed after conventional washing cycles. These "masses" prevail especially under cold temperature washing conditions and / or when in the order of addition to the washing machine first the laundry detergent is added, second the clothes and the last water (commonly known as "reverse order"). of addition "or" ROOA ", for its acronym in English). Such undesirable "masses" are also formed if the consumer loads the washing machine in an order of clothes, detergent and then water. In the same way, this mass formation can contribute to an incomplete supply of detergent in washing machines equipped with dispenser drawers or other dispensing devices, such as a granulette. In this case, an undesired result of undissolved detergent residues is obtained in the dispensing device.

It has been found that the cause of the aforesaid dissolution problem is associated with the "bridging" of a "gel-like" substance between the surfactant which contains particles to form undesirable "lumps". The substance similar to the gel is responsible for the unwanted "bridging" of the particles in "lumps" originates from the partial dissolution of the surfactant in the aqueous solutions for washing, where such partial dissolution causes the formation of a phase of highly viscous surfactant or a paste that is bonded or otherwise "bridged" with another surfactant that contains the "lump" particles. These undesired dissolution phenomena are commonly referred to as "gel lumps" formation. In addition to the "bridging" effect of the viscous surfactant, the inorganic salts have a tendency to hydrate, which also causes the "bridging" of the particles that were bound by hydration. In particular, the hydrated salts with one another form a box structure that presents an inadequate solution and finally ends up as a "lump" after the washing cycle. Therefore, it would be desirable to have a detergent composition that does not exhibit the dissolution problems identified above, so as to result in improved cleaning performance. The prior art is full of descriptions that address the dissolution problems associated with the granular detergent compositions. For example, the prior art suggests limiting the use and handling of inorganic salts that can cause lumps through "bridging" of the hydrated salts during the wash cycle. The specific relationships of the selected inorganic salts are contemplated in such a way as to minimize dissolution problems. However, such a solution restricts the flexibility of procedure and formulation that are necessary for the current commercialization of detergent products on a large scale. Various other mechanisms have been suggested by the prior art, all of which involve the alteration of the formulations, and in such a way reduce the formulation flexibility. As a consequence, it would be desirable to have a detergent composition having an improved solution without significantly inhibiting the flexibility of the inhibition. Thus, in spite of the prior art disclosures discussed in the preceding paragraphs, it would be desirable to have granular detergent compositions that exhibit improved solubility, have a better consumer appearance, and improved flowability and exhibit performance. of improved cleaning. It would also be desirable to have a detergent composition that exhibits such an improved solution without significantly inhibiting the flexibility of the formulation.

BRIEF DESCRIPTION OF THE INVENTION The present invention covers the above needs by providing a detergent composition having a controlled scale of heterogeneity between the selected chemical ingredients, which in turn, provides improved solubility or dissolution in the wash solutions, especially in solutions that are maintained at cold temperatures (ie, less than about 30 ° C), and have improved flowability of packaged granules for ease of handling and metering by the consumer. According to a first aspect of the present invention, a granular detergent composition having a homogeneity number of less than about 0.5 or greater than about one (1) is provided wherein the homogeneity number is defined by the formula: n N = Volume 'apart where XVOiumen is the ratio of the concentration of a selected detergent ingredient in the mixture component of particles containing the selected ingredient in the lowest concentration of any particulate component mixed to the concentration of the selected ingredient in the component of mixture in particles with the highest levels of that ingredient and Xparte is the ratio of the concentration of a detergent ingredient in a discrete volume of a particle (referred to hereinafter as "domains") with the lowest levels of that ingredient to the concentration of the detergent ingredient in a discrete discrete volume (ie, a domain) of the particle with the highest levels of the ingredient, from less than about 0.5 or greater to about 1. Preferably, the selected detergent ingredient on which the homogeneity number is based is concentration of surfactant. Preferably, the homogeneity number is greater than about 1.25 and preferably greater than 1.5.

In preferred embodiments, the detergent composition comprises at least about 50% by weight of particles having a geometric average particle diameter of about 500 microns to about 1500 microns with a geometric standard deviation of about 1 to about 2, wherein at least one portion of the particles contain a detersive surfactant and a builder. According to a second aspect of the present invention, a method for producing the aforementioned detergent composition is provided. The method comprises providing a granulated feed stream from detergent particles which are selected from at least two of the groups consisting of spray-dried granules, wet agglomerates, dry agglomerates, detergent auxiliary ingredients and mixtures thereof, which they pass the feed stream through at least one selected mixer of high speed, moderate speed, low speed, and low shear mixers to produce a detergent composition. Accordingly, it is an advantage of the invention to provide a granular detergent composition that exhibits improved solubility, has improved flowability and exhibits improved cleaning performance. It is also an advantage to have said detergent composition that presents such an improved solution without significantly inhibiting the flexibility of the formulation.

DETAILED DESCRIPTION OF THE PREFERRED MODALITY Definitions As used herein, the word "particles" means a full size range of a detergent or component end product, or the full size range of the particles, agglomerates or non-uniform granules in a product or mixture of detergent component. final. Specifically, it does not refer to a size fraction (that is, it represents less than 100% of the full size margin) if any of these types of particles, unless the size fraction represents 100% of a non-uniform particle in a mixture of particles. For each type of particle component in a mixture the full size range of the different particles of said type have the same or substantially similar composition regardless of whether the particles are in contact with other particles. For agglomerated components, the agglomerates themselves are considered as non-uniform particles and each non-uniform particle may comprise a composite of minor primary particles and binder compositions. As used herein, the phrase "geometric average particle diameter" means the geometric mean mass diameter of a set of non-uniform particles measured with any standard mass-based particle size measurement technique, preferably dry sieved. . As used herein, the phrase "standard geometric deviation" or "lapse" of a particle size distribution means the geometric amplitude of the normal logarithm function best suited to the particle size data mentioned in the preceding paragraphs, which can be achieved by the diameter ratio of 84.13 percentile divided by the 50th percentile diameter of the cumulative distribution (D ^. ^ / Dso); see Gotoh et al, Powder Technology Handbook, pp. 6-11, Meral Dekker 1997. As used herein, the phrase "builder" means any inorganic material having a "builder" performance in the context of detergency, and specifically, an organic or inorganic material that can remove the hardness of the water from the washing solutions. As used herein, the term "bulk density" refers to the volume density of uncompressed, uncapped powder by measuring it by placing an excess of powder sample through a funnel in a smooth metal container (e.g. , a cylinder of 500 ml in volume), removing the excess from the edge of the container, measuring the remaining mass of powder and dividing the mass between the volume of the container. The granular detergent composition of the present invention achieves the desired benefits of solubility and flowability through providing a homogeneous detergent composition wherein the homogeneous detergent contributes to the aforementioned benefits. The homogeneity number describes the distribution of ingredients within specific particles and between particles in a composition. In the past, it was considered that the homogeneous distribution of key ingredients such as surfactant was optimal, measured between particles as well as within a given particle domain structure. In this way, the detergent composition would consist of a uniform type of particle made from a combination of detergent ingredients, such as spray-dried detergent ingredients and had significant disadvantages of solubility. In recent years, detergent compositions have consisted of different particles of double or multiple particle systems. Although these multi-particle systems, for example, spray-dried granules and agglomerates, may differ in shape and / or composition between particle types, these detergent products also suffer from solubility disadvantages. On the other hand, the present invention relates to the surprising discovery that specific ingredient distributions, whether between particulate blending components or within a defined domain microstructure of a specific particulate component, improve many product attributes such as solubility attributes and physical attributes such as flowability, etc. Specifically, the present invention relates to a detergent composition having a homogeneity number of less than about 0.5 or greater than about 1.0, preferably, less than 0.25 or greater than 1.25 and preferably greater than about 1.5. The homogeneity number is represented by the formula: HN = Xvoiumen / Xparte in done XVOiumen measures the degree of homogeneity of composition between components of mixture in particles within the product composition, while Xparte is the measure of the homogeneity of composition within of a defined domain structure of the individual particles comprising a specific particulate component. Thus, Xvoiumen is the ratio of the concentration of the selected ingredient in the particle with the lowest non-zero level of that ingredient to the concentration of the selected ingredient in the particle with the highest level of the selected ingredient and Xparte is the ratio of the concentration in the discrete volume with the lowest amount of the selected ingredient at the concentration in the discrete volume of the particle having the highest quantities of the selected ingredient. Accordingly, in a detergent composition, Xvoiumen is the ratio of the concentration of a selected detergent ingredient such as surfactant, improver, polymer, etc. in component in particle with the lowest non-zero level of the selected ingredient at the concentration of the selected ingredient in the particulate component with the highest level of the selected ingredient. This provides the homogeneity between particles in the composition. In this way, XVOiumen is represented by the formula: - ^ • volu in ^ min / max where Xmn is the concentration of the selected ingredient in the particles in the composition with the lowest levels of the selected ingredient and Xmax concentration of a detergent ingredient selected in the particles in the composition with the highest levels of the selected ingredient. For example, for a detergent composition in which all particles have the same concentration such as a spray-dried granule with an active concentration of 25% surfactant, XVOiumen would be equal to one (1) or 0.25 / 0.25. However, in a composition which comprises a spray-dried granule of 20% surfactant and a detergent agglomerate of 30% detergent active, XVOiumen would be equal to 0.67 or 0.2 / 0.3. Xparteßs the ratio of the concentration of a selected detergent ingredient such as surfactant, enhancer, etc. through domains within the same particle, or in other words, a measure of the homogeneity of the individual particle. Xparte is the ratio of the selected ingredient in discrete domains of the particle. Xparte is the ratio of the concentration in the domain with the lowest concentration of the ingredient to the concentration of the selected ingredient in the domain with the highest concentration within the same particle. Thus, Xparte is represented by the formula: • apart = mir Xmax where Xmn is the concentration of the selected ingredient in the discrete area in the particle with the lowest levels of the selected ingredients and Xmax concentration of a selected detergent ingredient in the areas discrete in the particle with the highest levels of the selected ingredient. A discrete volume or domain of the present invention is one in which there is a clear morphological difference between the domains; normally a domain considers more than 1%, preferably, 5% of the volume of the particle. For example, a particle that is homogeneous throughout the particle has only one (1) domain. Thus, a particle which has the same total concentration as a spray-dried granule with an active concentration of 25% surfactant detergent, Xpart would be equal to one (1) or 0.25 / 0.25 since the particle contains only one domain. However, in a particle, which is agglomerated from two different starting ingredients such as spray dried granules having 5% surfactant and dry detergent agglomerates having 50% surfactant to form mixed agglomerates as defined in the present (ie, when the composition differences in the starting materials remain clearly evident within the microstructure of the resulting mixed agglomerate), Xpart would be equal to 0.1 or 0.05 / 0.5. when a composition contains more than one particulate component, is Xparte taken as the average of Xm? n / Xma? for each component. The homogeneity number of the present invention will be calculated in particles which comprise the volume of the detergent composition. In this way, the particles which individually or collectively consider less than about 10% by weight of the finished composition should not be used in the calculation of the homogeneity number. These low level ingredients usually include mixed ingredients such as enzymes, bleaching ingredients, perfume ingredients, sodium carbonate, sodium sulfate and other minor additions. Although it is not intended to be limited to theory, it is considered that by concentrating certain ingredients and / or selectively separating them, gel formation at the time of dissolution can be avoided due to chemical interactions between the particles. The present invention provides a detergent composition having superior solubility and flowability performance due to the homogeneity profile of the composition. Preferably, the geometric average particle diameter in the particles is from about 400 microns to about 1500 microns, preferably from about 500 microns to about 1200 microns, and preferably about 600 microns to about 1000 microns. The particle size distribution is defined by a relatively narrow geometric deviation or "lapse" so as not to have many particles outside the target size. Accordingly, the geometric standard deviation is preferably from about 1 to about 2, preferably from about 1.0 to about 1.7, preferably from about 1.0 to about 1.4, and preferably from about 1.0 to about 1.2. The average volume density of the particles preferably is at least about 400 g / l, preferably at least about 550 g / l, and preferably at least about 600 g / l. Although it is not intended to be limited to the theory, solubility is considered to be improved as a result of the particles in the detergent composition having the aforementioned homogeneity profile. Specifically, as a result of the particles being more uniform in size, the current "points of contact" between the particles in the detergent composition are reduced, which in turn reduces the "bridging effect" commonly associated with the difficulties of "gel lumps" dissolution of granular detergent compositions. The above granular detergent compositions contained particles of homogeneity number in the scale from about 0.5 to about 1 and particle diameter sizes which leads to more points of contact between the particles. For example, the finer particles have more contacts between particles per unit volume than the rougher particles, and the increase in the contacts per unit volume increases the force by volume of the gel formations in lumps, thus increasing the probability that said gel formations in lumps will persist through the agitation in the wash cycle and leave residues undesirable in fabrics. The homogeneity number, level and uniform size of the particles in the granular detergent composition of the present invention avoid such problems. By "a portion" of the particles, it is meant that at least some particles in the detergent composition contain a detersive surfactant and / or a builder to provide the fundamental improvement blocks of a typical detergent composition. The different surfactants and enhancers, as well as their respective levels in the composition are discussed below. Typically, the detergent composition will contain from about 1% to about 50% by weight of a detersive surfactant and from about 1% to about 75% by weight of a builder. Another important attribute of the granular detergent products of this invention is the shape of the individual particles. The shape can be measured in a number of different ways known to the person skilled in the art. Such method is to use optical microscopy with Optimus image analysis software (V5.0). The important parameters calculated are: "Circularity" which is defined as (measured perimeter length of the particle image) 2 / (measured area of the particle image). The circularity of a perfectly smooth sphere (minimum circularity) in 12.57; Y "Aspect Ratio" which is defined as the length / width of the particle image. Each of these attributes is important and can be averaged over the detergent composition granulated by volume. In addition, the combination of the two parameters defined by the product of the parameters is also important (that is, both must be controlled to obtain a product with good appearance). Preferably, the granular detergent compositions of this invention have circularity of less than about 50, preferably less than about 30, preferably less than about 23, preferably less than about 18. Also preferred are granular detergent compositions with aspect ratios less than 2. , preferably less than 1.5, preferably less than 1.3, preferably less than 1.2. Additionally, it is preferred to have a uniform distribution of shapes between the particles in the composition. Specifically, the granular detergent compositions of this invention have a standard deviation of the circularity number distribution of less than 20, that is, preferably less than 10, preferably less than 7, preferably less than 4. And the standard deviation of the The number distribution of the preferred aspect ratios is less than 1, preferably less than 0.5, even preferably less than 0.3, preferably less than 0.2. In an especially preferred process of the present invention, the granular detergent compositions are produced wherein the product of circularity and aspect ratio is less than about 100, preferably less than 50, preferably less than 30, and preferably less than 20. Also, they prefer granular detergent compositions with the standard deviation of the product number distribution of circularity and aspect ratio less than about 45, preferably less than about 20, preferably less than about 7, preferably less than about 2. Preferred detergent compositions of this invention meet at least one and preferably all the attribute measurements and standard deviations as defined above, which are homogeneity number, whiteness, color, uniformity, circularity and aspect ratio. The present invention also comprises a process for the production of a detergent composition having a superior homogeneity profile. The detergent granules of the present invention comprise at least one detergent active material and are preferably selected from spray-dried detergent granules, wet detergent agglomerates, dry detergent agglomerates and detergent auxiliary ingredients and other granules normally incorporated in a detergent composition. The granules may be in the form of a particle, agglomerate or flake. Auxiliary detergent ingredients include, but are not limited to, raw materials such as carbonates, phosphates, sulfates, zeolites, surfactants, bleaches, enzymes, perfumes or the like. Of course, other known ingredients can also be included in a conventional manner. The spray-dried detergent granules include those particles which are manufactured by a conventional spray-drying technique, wherein a suspension of detergent materials is prepared and dispersed downward in a gas upflow stream to dry the particles. From the process, a free flowing dry material is produced. The wet detergent agglomerates include those particles that are manufactured through a granulation-type process wherein the detergent auxiliary ingredients such as those described above are mixed with a liquid binder material such as a surfactant or precursor thereof in a mixer or mixer. series of mixers to form granules of detergent materials. These particles are known as "agglomerates in wet" until they are dried and as dry agglomerates after leaving a drying stage. Therefore, the present invention involves the introduction of both raw materials such as surfactants and enhancers, and the introduction of previously formed detergent granules for continuous processing of the granules. In a preferred embodiment of this invention, the granules of the present invention are agglomerated from a mixture of feed streams such as spray-dried granules, dry agglomerates and optionally detergent auxiliaries which are agglomerated in an agglomeration process such as that described later. Preferred agglomerates are referred to herein as mixed agglomerates. The dry or wet agglomerates of the present invention are usually formed by an agglomeration of a highly viscous surfactant paste or a liquid acid precursor of a surfactant and the aforementioned detergent auxiliary ingredients or granules formed, such as agglomerates. of spray-dried granules or detergent auxiliaries as described above, can be substituted. The agglomeration can be performed in a high or moderate speed mixer after which an optional low or moderate speed mixer can be employed for further agglomeration, if necessary. Low speed mixers according to the present invention may include Alternatively, agglomeration may be performed in a simple mixer which may be of low, moderate or high speed. The particular mixer used in the present process should include spraying or grinding and agglomerating tools, so that both techniques can be performed simultaneously in a simple mixer. For that purpose, it has been found that the first processing step can be completed successfully, under the process parameters described herein, in a Lodige KM ™ moderate speed mixer (Plowshare), Lodige CB ™ high speed mixer. , or mixers made by Fukae, Drais, Schugi or similar brand blender. The Lodige KM ™ moderate speed mixer (Plowshare), which is a preferred mixer for use in the present invention, comprises a horizontal hollow static cylinder having a centrally mounted rotation axis around which different plow-shaped knives are attached . Preferably, the shaft rotates at a speed from about 15 rpm to about 140 rpm, preferably from about 80 rpm to about 120 rpm. Grinding or spraying is done through cutters, generally smaller in size than the rotary axis, which preferably operates at approximately 3600 rmp. Other mixers similar in nature which are suitable for use in processes include the Lodige Ploughshare ™ mixer and the Drais®KT 160 mixer. Generally, in the process of the present invention, the shear force will not be greater than the shear force produced by a Lodige KM mixer with a tip speed of plows less than 30 m / s or even less than 10 m / s or even less. Preferably, the average residence time of the different detergent ingredients in the low, moderate or high speed mixer is preferably in the range of about 0.1 seconds to about 30 minutes, preferably the residence time is about 0.5 to about 5 minutes. minutes In this way, the density of the resulting detergent agglomerates is at the desired level.

Normally, this agglomeration is followed by a drying step. This drying step can be performed on a wide variety of equipment including but not limited to a fluid bed drying apparatus. Examples of characteristic dryers include fixed or vibrating; of rectangular bed or round bed; or straight or serpentine dryers. Manufacturers of such dryers include Niro, Bepex, Spray Systems and Glatt. By way of example, an apparatus such as a fluidized bed can be used to dry, while air entrainment can be used to cool if necessary. Air entrainment can also be used to force out "fine" particles so that they can be recycled to the particle agglomeration process. The agglomeration may consist of the step of drying an additional binder in the fluid bed mixtures to facilitate the production of the desired detergent particles. A binder is added for the purpose of improving agglomeration by providing a "binder" or "stickiness" agent for the detergent components. Preferably, the binder is selected from the group consisting of water, anionic surfactants, nonionic surfactants, polyethylene glycol, polyvinylpyrrolidone, acetates, polyacrylates, citric acid and mixtures thereof. Other suitable binding materials including those mentioned herein are described in Beerse et al, U.S. Pat. No. 5,108,646 (Procter &Gamble Co.), the disclosure of which is incorporated herein by reference.

Another optional processing step for forming the particles of the present invention includes continuously adding a coating agent such as zeolites, recycled "fines" such as those described above, and fuming silica in the mixer to improve the particle color, increase the "Whiteness" of the particle or facilitate the free-flowing capacity of the resulting detergent particles and to avoid over-agglomeration. When recycled fines are used as the coating agent, the fines preferably have a size scale of approximately 0.01 to 0.5 times the average particle size of the largest particles. The granule coating will also improve the integrity of the fines and provide resistance to abrasion and wear during handling. In addition, the detergent starting materials can be fed into a pre-mixer, such as a Lodige CB mixer or a twinworm extruder, before entering the mixer. This step, although optional, actually facilitates agglomeration. In addition, spray-dried detergent granules, which comprise tower blown particles, are particularly preferred in the present invention. In this process, the granules are formed by the preparation of a suspension of surfactant materials, water and materials of detergent auxiliary ingredients. The resulting suspension is passed to a tower where the suspension is dispersed in an air stream at temperatures typically ranging from about 175 ° C to about 375 ° C to dry the detergent suspension and form the detergent particles. Typically, the resulting densities of these particles are in the range of about 200 to about 600 g / i. The particles of the present invention comprise at least about 50% by weight of particles having a geometric average particle diameter of about 500 microns. at about 1500 microns and preferably, they have a geometric standard deviation of about 1 to about 2. Preferably, the geometric standard deviation is from about 1.0 to about 1.7, preferably from about 1.0 to about 1.4. The granular detergent composition resulting from the processes may comprise fine particles or smaller size, wherein "fine particles" are defined as particles having a geometric average particle diameter that is less than about 1.65 standard deviations below the geometric average particle diameter selected from the detergent composition granulated in a given span or geometric standard deviation. Large or larger particles may also exist where "large particles" are defined as particles having a geometric average particle diameter that is greater than about 1.65 standard deviations above the geometric average particle diameter selected from the detergent composition granulated in a given span or geometric standard deviation. Preferably, the fine particles are separated from the granular detergent composition and returned to the process by adding them to at least one of the mixers and / or the fluid bed dryer, as described in detail below. Similarly, the large particles are preferably separated from the granular detergent composition and then fed to a shredder where their geometric average particle diameter is reduced. After the geometric average particle diameter of the large particles is reduced, they are returned to the process by adding them to at least one of the mixers and / or the fluid bed dryer. In a preferred processing of the present invention, the granules of the present invention are produced in a fluidized bed through the combination of spray dried granules, auxiliary ingredients and dry agglomerates. A liquid binder material such as silicates, polyethylene glycol, surfactants and precursors thereof and many other materials can be added to the fluid bed to improve agglomeration. Optionally, the feedstocks are passed through a premixer or series of mixers, such as a moderate speed mixer as described above. The fluidized bed is preferably operated so that the flow number FN of the fluid bed is at least about 2.5 to about 4.5. The flow number (FNm) is a ratio of the excess velocity (Ue) of the fluidizing gas and the particle density (Pp) relative to the mass flow (qpq) of the liquid dispersed in the bed at a normalized distance (D0) of the spray device. The flow number provides an estimate of the operational parameters of a fluidized bed to control the granulation within the bed. The flow number can be expressed as either the mass flow as determined by the following formula: or as the volume flow as determined by the formula: FNv = log .o [. { EU} / qViiq] where qv? g is the volume of spray in the fluid bed. The calculation of the flow number and a description of its utility is fully described in WO 98/58046, the description of which is incorporated herein by reference. In addition, the fluidized bed is operated in a number of Stokes less than about 1, preferably from about 0.1 to about 0.5. The Stokes number is a measure of particle coalition to describe the degree of mixing that occurs in the particles in a piece of equipment such as the fluid bed. The Stokes number is measured by the formula: Number of Stokes = 4pvd / 9u where p is the apparent particle density, v is the excess velocity, d is the average particle diameter and u the viscosity of the binder. The Stokes number and a description of its utility are described in detail in WO 99/03964, the disclosure of which is incorporated herein by reference. The granules of the present invention are passed in a fluid bed dryer having multiple internal "stages" or "zones." A stage or zone is any discrete area within the dryer, and these terms are used interchangeably herein. The processing conditions within a stage may be different or similar to other stages in the dryer. It is understood that two adjacent dryers equate to a single dryer having multiple stages. The different feed streams of granules and coating material can be added in the different stages, depending for example on the particle size and humidity level of the feed stream. The feeding of different streams at different stages can minimize the heat load in the dryer, and optimize the particle size and shape as defined herein. Normally, the fluid bed mixer of the present invention comprises a first spray zone where the binder material is applied. The spray zone involves spraying the binder in aqueous form or in suspension on the fluidized particles. Typically, the bed is fluidized with hot air in order to dry or partially dry the moisture from the spray as it is applied. Spraying is achieved through nozzles capable of supplying a fine or atomized spray of the coating mixture to obtain complete coverage of the particles. Typically, the droplet size of the atomizer is less than about 2 times the particle size. This atomization can be achieved either through a conventional double fluid nozzle with atomizing air, or alternatively by means of a conventional pressure nozzle. To achieve this type of atomization, the rheology of the suspension or solution is usually characterized by a viscosity of less than about 500 centipoise, preferably less than 200 at the point of atomization.

Although the location of atomization in the fluid bed can be mainly anywhere, the preferred location is a positioning that allows vertical descending spray of the coating mixture such as a top spray configuration. For best results, the nozzle location is placed at or above the fluidized height of the particles in the fluid bed. The fluidized height is usually determined by an overflow or dump head height. The coating area of the fluid bed is then followed by a drying zone and a cooling zone. Of course, one skilled in the art will recognize that alternative arrangements for obtaining the coated particles resulting from the present invention are also possible. The normal conditions within a fluid bed apparatus of the present invention include (i) from about 1 to about 20 minutes of average residence time, (ii) from about 100 to about 600 mm depth of non-fluidized bed, (iii) ) a droplet size of 2 times the particle size, preferably not more than about 100 microns, preferably not more than 50 microns, (iv) from about 150 to about 1600 mm of spray height from the fluid bed plate or preferably, 0-600 mm from the fluid bed cover, (v) from about 0.1 to about 4.0 m / s fluidization velocity, preferably from 1.0 to 3.0 m / s, and (vi) from about 12 to about 200 ° C. of bed temperature, preferably from 15 to about 100 ° C. Again, one skilled in the art will recognize that the conditions in the fluid bed may vary depending on a number of factors. The coated granules leaving the coating mixer may themselves comprise a fully formulated detergent composition or in preferred embodiments, may be mixed with additional ingredients, such as bleaching agents, enzymes, perfumes, uncoated detergent particles, and many other ingredients to produce a fully formulated detergent composition.

Detergent Components The surfactant system of the detergent composition can include anionic, nonionic, zwitterionic, ampholytic and cationic classes, and compatible mixtures thereof. Detergent surfactants are described in the US patent. 3,664,961, Norris, issued May 23, 1972, and in the U.S. patent. 3,919,678, Laughiin et al., Issued December 30, 1975, both incorporated herein by reference. Cationic surfactants include those described in the U.S.A. 4,222,905, Cockrell, issued September 16, 1980, and in the patent of E.U.A. 4,239,659, Murphy, issued December 16, 1980, both incorporated herein by reference. Non-limiting examples of surfactant systems include the conventional Ci-C.ß alkylbenzenesulfonates ("LAS") and C.6-C2o, primary, branched-chain and random alkylsulfates ("AS"), the alkyl sulfates (2, 3) Secondary C.0-C18 of the formula CH3 (CH2) x (CHOS03"M +) CH3 and CH3 (CH2) and (CHOSO3" M +) CH2CH3 where xy (y + 1) are integers of at least 7 , preferably at least about 9, and M is a water-soluble cation, especially sodium, unsaturated sulfates such as oleyl sulfate, Co-C.β alkylalkoxy sulfates ("AEXS", especially EO-1-7 ethoxysulfates), C10 alkylalkoxycarboxylates. C 8 (especially the ethoxycarboxylates, EO 1-5), glycerol ethers of Co-C.β, alkyl polyglucosides of Co-Cs and their corresponding sulphated polyglycosides, and alpha-sulfonated fatty acid esters of C 2 -C. 8-If desired, conventional non-ionic and amphoteric surfactants such as alkylethoxylated ("AE") of C.2-C.8 inc using the so-called narrow-chain alkylethylated and C 1 -C 2 alkylphenyl-alkoxylated ethoxylates (especially ethoxylates and ethoxy / mixed propoxy), C.sub.2-C.sub.8 betaines and sulfobetaines ("sultaines"), C? 0-C18 amine oxides and the like, may also be included in the surfactant system. N-alkylpolydroxylic fatty acid amides of C .o-C.e may also be included. Typical examples include the N-methylglucamides of C.2-C.8. See WO 9,206,154. Other surfactants derived from sugar include the N-alkoxy-polyhydroxy fatty acid amides, such as N- (3-methoxypropyl) glucamide from C.o-C.8. The N-propyl to N-hexylglucamides of C.2-C.8 can be used for low foaming. Conventional C0-C2o soaps can also be used. If high foaming is desired, the branched-chain soaps of C.o-C .6 can be used. Mixtures of anionic and nonionic surfactants are especially useful. Other useful conventional surfactants are listed in standard texts. The detergent composition can, and preferably includes, a builder. The detergency builders are generally selected from various water-soluble phosphates, polyphosphates, phosphonates, polyphosphonates, carbonates, silicates, borates, polyhydroxysulfonates, polyacetates, carboxylates and polycarboxylates of alkali metal, ammonium or substituted ammonium. Alkali metal salts, especially sodium, of the above are preferred. Preferred for use herein are phosphates, carbonates, silicates, C0-C8 fatty acids, polycarboxylates, and mixtures thereof. Most preferred are sodium tripolyphosphate, tetrasodium pyrophosphate, citrate, tartrate mono- and di-succinates, sodium silicate, and mixtures thereof (see below). Specific examples of inorganic phosphate builders are sodium potassium tripolyphosphate, pyrophosphate, polymeric metaphosphate having a degree of polymerization of about 6 to 21, and orthophosphates. Examples of polyphosphonate builders are the sodium and potassium salts of ethylene diphosphonic acid, the sodium and potassium salts of 1-hydroxy-1,1-diphosphonic acid of ethane and the sodium and potassium salts of acid 1, 1, 2 -triphosphonic acid. Other phosphorus builder compounds are described in the U.S. Patents. 3,159,581; 3,213,030; 3,422,021; 3,422,137; 3,400,176 and 3,400,148, all incorporated herein by reference.

Examples of inorganic builders, not phosphorus builders, are carbonate, bicarbonate, sesquicarbonate, tetraborate decahydrate of sodium and potassium, and silicates having a weight ratio of SiO 2 to alkali metal oxide of about 0.5 to about 4.0, preferably around 1.0 to about 2.4. The non-phosphorus, water soluble organic builders useful herein include the various alkali metal, ammonium, and substituted ammonium polyacetates, carboxylates, polycarboxylates, and polyhydroxysulfonates. Examples of polyacetate and polycarboxylate builders are the sodium, potassium, lithium, ammonium and substituted ammonium salts of ethylenediaminetetraacetic acid, nitrilotriacetic acid, oxydisuccinic acid, melific acid, benzene polycarboxylic acids and citric acid. Polymeric polycarboxylate builders are set forth in the U.S.A. 3,308,067, Diehl, issued March 7, 1967, the disclosure of which is incorporated herein by reference. Such materials include the water-soluble salts of homo- and co-polymers of aliphatic carboxylic acids such as maleic acid, itaconic acid, mesaconic acid, fumaric acid, aconitic acid, citraconic acid and methylenemalonic acid. Some of these materials are useful as the water-soluble anionic polymer as hereinafter described, but only if it is in an intimate mixture with the non-soap anionic surfactant. Other polycarboxylates suitable for use herein are the polyacetal carboxylates described in the U.S.A. 4,144,226, issued March 13, 1979 to Crutchfield et al., And patent of E.U.A. 4,246,495, issued March 27, 1979 to Crutchfield et al., Both incorporated herein by reference. These polyacetal carboxylates can be prepared by coupling, under polymerization conditions, a glyoxylic acid ester and a polymerization initiator. The resulting polyacetal carboxylate ester is attached to chemically stable end groups to stabilize the polyacetal carboxylate against rapid depolymerization in alkaline solution, converted to the corresponding salt, and added to a detergent composition. Particularly preferred polycarboxylate builders are ether carboxylate builder compositions comprising a combination of tartrate monosuccinate and tartrate disuccinate described in the U.S.A. 4,663,071, Bush et al., Issued May 5, 1987, the disclosure of which is incorporated herein by reference. Water-soluble silicate solids represented by the formula SiO 2 * M 2 O, M being an alkali metal and having a weight ratio of S 2 O 2: M 2 O of from about 0.5 to about 4.0, are useful salts of the detergent granules of the invention at levels of about 2% to about 15% on an anhydrous weight basis, preferably from about 3% to about 8%. Anhydrous or hydrated particulate silicate can also be used. Any number of additional ingredients can also be included as components in the granular detergent composition. These include other detergency builders, bleaches, bleach activators, foam enhancers or suds suppressors, anti-rust and anti-corrosion agents, soil suspending agents, soil release agents, germicides, pH adjusting agents , alkalinity sources not detergent builders, chelating agents, smectite clays, enzyme stabilizing agents and perfumes. See the patent of E.U.A. 3,936,537, issued February 3, 1976 to Baskerville, Jr. et al., Incorporated herein by reference. Bleach agents and activators are described in the US patent. 4,412,934, Chung et al, issued November 1, 1983, and in the U.S. patent. 4, 483,781, Hartman, issued November 20, 1984, which are incorporated herein by reference. Chelating agents are also described in the patent of E.U.A. 4,663,071, Bush et al, from column 17, line 54, to column 18, line 68, incorporated herein by reference. Foam modifiers are also optional ingredients, and are described in the U.S. Patents. 3,933,672, issued January 20, 1976 to Bartoletta et al, and 4,136,045, issued January 23, 1979 to Gault et al., Both incorporated herein by reference. Smectite clays suitable for use herein are described in the U.S.A. 4,762,645, Tucker et al., Issued August 9, 1988, column 6, line 3, column 7, line 24, incorporated herein by reference. Other detergency builders suitable for use herein are listed in the Baskerville patent, column 13, line 54, column 16, line 16, and in the U.S. patent. 4,663,071, Bush et al., Issued May 5, 1987, both incorporated herein by reference. The following examples are presented for purposes of illustration only and are not to be construed as limiting the scope of the appended claims in any way.

EXAMPLE I A finished detergent composition is produced by mixing or dry-blending two feed streams. The first is 20% by weight of granules dried by spraying surfactant. The second is 30% by weight agglomerated granule of surfactant. The two particles are mixed at 50% by weight each. The homogeneity number of the finished detergent is 0.67, calculated from XVOiumen = 0.2 / 0.3 = 0.67 and XParte = (0.2 / 0.2) + (0.3 / 0.3) / 2 = 1 EXAMPLE II A detergent composition is produced in a batch process in a fluidized bed having a depth of 15.24 cm and a weight per batch of 1500 g. The inlet temperature of the bed was 130 ° C, the bed temperature was 45 ° C and the air velocity was 1 m / s. The feed comprises 50% dry agglomerates having an active concentration of 50% surfactant and 50% spray dried granules having an active concentration of surfactant of 5%. A total of 250 grams of a 30% by weight solution of PEG 4000 was dispersed in the fluidized bed to agglomerate the feed ingredients in a mixed agglomerate. The final composition has an average particle size of ~ 600um and a homogeneity number of 10, calculated from and Xpart = 0.1 of Xm? N (0.05) / Xmax (0.5).

EXAMPLE III A detergent composition is produced by dry blending the feed streams of Example 2 without agglomeration of the two streams. The finished composition has a homogeneity number of 0.1, calculated from XVOiumen = 0.05 / 0.5 = 0.1 and Xpart = (0.05 / 0.05 + 0.5 / 0.5) / 2 = 1. Thus, having described the invention in detail, it will be obvious to those skilled in the art that various changes can be made without departing from the scope of the invention and that this will not be considered limited to those described in the specification.

Claims (18)

NOVELTY OF THE INVENTION CLAIMS

1. - A granular detergent composition having a homogeneity number, HN, as defined by the equation: rl N = Xvolu men 'where XVOiumep is the ratio of the concentration of a detergent ingredient selected in the particle to the lowest level of said ingredient to the concentration of said ingredient in the particle with the highest level of said ingredient and Xpar.e is the ratio of the concentration of a discrete area of a particle with the lowest level of said ingredient to the concentration of the discrete area of the same particle with the highest level of said ingredient, from less than about 0.5 or greater to about 1.

2.- The detergent composition in accordance with the claim 1, further characterized in that said selected detergent ingredient is surfactant.

3. The detergent composition according to claim 1, further characterized in that said homogeneity number is greater than about 1.25.

4. The detergent composition according to claim 1, further characterized in that at least about 50% by weight of particles having a geometric average particle diameter of about 400 microns to about 1500 microns with a geometric standard deviation of about 1 to about 2, wherein at least a portion of said particles contain a detersive surfactant and a builder.

5. The granular detergent composition according to claim 4, further characterized in that said particles comprise at least about 75% by weight of said detergent composition.

6. The granular detergent composition according to claim 4, further characterized in that the geometric standard deviation is from about 1.0 to about 1.7.

7. The granular detergent composition according to claim 4, further characterized in that the geometric standard deviation is from about 1.0 to about 1.4.

8. The granular detergent composition according to claim 4, further characterized in that said particles comprise at least about 90% by weight of said detergent composition.

9. The granular detergent composition according to claim 4, further characterized in that the geometric average particle diameter of said particles is from about 600 microns to about 1200 microns.

10. The granular detergent composition according to claim 4, further characterized in that the geometric standard deviation is from about 1.0 to about 1.2.

11. - The granular detergent composition according to claim 4, further characterized in that said particles have an aspect ratio of less than about 2.

12. The granular detergent composition according to claim 4, further characterized in that said particles have a ratio of aspect less than about 1.3.

13. A process for producing a granular detergent composition comprising the steps of providing a feed stream of detergent particles having at least one detergent active, said detergent particles being selected from at least two of the groups consisting of granules dried by sprinkling, wet agglomerates, dry agglomerates, detergent auxiliary ingredients and mixtures thereof, which pass said feed stream through at least one selected mixer of high speed, moderate speed, low speed, and low shear mixers for produce a detergent composition having a homogeneity number, HN, defined according to the equation: HN = Xvolume / Xpart where Xvoiumen is the ratio of the concentration of a detergent ingredient selected in the particle to the lowest non-zero level of said ingredient a the concentration of said ingredient in the particle with the highest level high of said ingredient and Xparte is the ratio of the concentration of a discrete area of a particle with the lowest level of said ingredient to the concentration of the discrete area of the same particle with the highest level of said ingredient, from less than about 0.5 or greater to about 1.

14. The method according to claim 13, further characterized in that said feed stream comprises spray-dried granules and dry detergent agglomerates.

15. The method according to claim 13, further characterized in that said mixer is a low shear mixer.

16. The method according to claim 15, further comprising steps for passing said feed stream through a moderate speed mixer before passing through said low shear mixer.

17. The process according to claim 16, further characterized in that a liquid detergent binder is added to either the low shear mixer or said moderate speed mixer or both, to improve the agglomeration of said feed stream.

18. The method according to claim 13, further characterized in that said homogeneity number is greater than about 1.25.