MXPA00000523A - Process for making a low density detergent composition by controlling nozzle height in a fluid bed dryer - Google Patents

Abstract

A process for preparing low density detergent agglomerates having a density in a range from about 300 g/l to about 550 g/l is provided. The process involves the steps of:(a) agglomerating a detergent surfactant paste or precursor thereof and dry starting detergent material in a first high speed mixer to obtain agglomerates;(b) mixing the agglomerates in a second high speed mixer to obtain built-up agglomerates;and (c) feeding the built-up agglomerates into a fluid bed dryer in which a binder is sprayed via a nozzle having a height of from about 25 cm to about 60 cm from the distributor plate of the fluid bed dryer such that the built-up agglomerate are dried and agglomerated to form the desired low detergent agglomerates.

Description

PROCEDURE FOR PREPARING A COMPOSITION OF LOW DENSITY DETERGENT CONTROLAN DCA HEIGHT OF THE NOZZLE IN A FLAT BED DRYER FIELD OF THE INVENTION The present invention relates generally to a process for producing a low density detergent composition. More particularly, the invention relates to a process during which low density detergent agglomerates are produced by feeding a liquid acid precursor or an anionic surfactant paste and drying the starting detergent material sequentially in two mixers of anionic surfactant. high speed, followed by a fluid bed dryer having a nozzle height appropriately selected to spray on a binder. The process produces a free-flowing low density detergent composition, which can be sold commercially as a conventional non-compact detergent composition, or used as a mixture in a low dose "compact" detergent product.

BACKGROUND OF THE INVENTION Recently, there has been considerable interest within the detergent industry for laundry detergents that are ^ JZf • "* § * *% ^^ -" compact "and, therefore, have low dosage volumes.For the production of these low-dosage detergent products, many attempts have been made to produce detergents from high density, for example, with a density of 600 g / l or more, low-dosage detergents are currently in high demand because they conserve resources and can be marketed in small packages that are more convenient for consumers. the degree to which modern detergent products need to be "compact" in nature remains uncertain, in fact, many consumers, especially in developing countries, continue to prefer higher dosage levels in their respective laundry operations. the need in the art to produce modern detergent compositions for flexibility in the ultimate density of the composition f In general, there are three primary types of procedures by which granules or detergent powders can be prepared. The first type of process involves spray drying an aqueous detergent suspension in a spray drying tower to produce highly porous detergent granules. In the second type of process, the different detergent components are mixed dry, after which they are agglomerated with a binder such as anionic or nonionic surfactant. In the two previous procedures, the important factors that determine the density of the resulting detergent granules are the *? -. density, porosity, surface area and the shape of the different starting materials, and their respective chemical composition. However, these parameters can only be modified within a limited scale. Therefore, the flexibility in the substantial agglomeration density can only be achieved by additional process steps that lead to a lower density of the detergent granules. There have been many attempts in the art to provide methods that increase the density of detergent granules or powders. Particular attention has been given to the densification of spray-dried granules by post-tower treatment. For example, an attempt involves an intermittent procedure in which granular or spray-dried detergent powders containing sodium tripolyphosphate and sodium sulfate are densified and spheronized in a Marumerizer®. This apparatus comprises a rotating table, made rough and substantially horizontal, located inside and at the base of a substantially vertical smooth wall cylinder. However, this process is essentially an intermittent process and is therefore less convenient for the large-scale production of detergent powders. More recently, other attempts have been made to provide continuous processes to increase the density of spray-dried or "post-tower" detergent granules. Typically, said processes require a first apparatus that pulverizes or crushes the granules, and a second apparatus that increases the density of the pulverized granules by agglomeration. Although these procedures **. achieve the desired increase in density by treating or densifying post-tower, or sprinkling dried granules, a process that has the flexibility to provide low density granules.Also, all of the aforementioned processes are primarily aimed at densifying or otherwise processing Currently, the relative amounts and types of materials subjected to spray drying processes in the production of detergent granules have been limited, for example, it has been difficult to achieve high levels of surfactant in the resulting detergent composition. , a feature that facilitates the production of detergents in a more efficient way, so it would be convenient to have a procedure by which detergent compositions can be produced without having the limitations imposed by conventional spray drying techniques. it is also replete a of process descriptions involving the agglomeration of detergent compositions. For example, attempts have been made to agglomerate builders by mixing zeolite and / or layered silicates in a mixer to form free flowing agglomerates. Although such attempts suggest that their process can be used to produce detergent agglomerates, they do not provide a mechanism by which starting detergent materials in the form of surfactant pastes or precursors thereof, liquid and dry materials can effectively agglomerate in agglomerates. crisp and free flowing detergents that have low densities instead of high densities. In the past, attempts to produce such low density agglomerates involved an unconventional detergent ingredient, which is usually expensive, in addition to the cost of the detergent product. An example of the above involves an agglomeration process with inorganic double salts such as Burkeite to produce the desired low density agglomerates. Accordingly, there is a need in the art to have a process for producing a low density detergent composition that is sourced directly from starting detergent ingredients without the need to include particularly expensive ingredients. Likewise, there is a need for such a process that is more efficient, flexible and economical to facilitate the large-scale production of detergents of high as well as low dosage levels.ANTECEDENTS OF THE TECHNIQUE The following references are directed to densify spray-dried granules: Appel et al., U.S. No. 5,133,924 (Lever); Bortolotti et al., Patent of E.U.A. No. 5,160,657 (Lever); Johnson et al., British Patent No. 1,517,713 (Unilever); and Curtis, European patent application 451.894. The following references are directed to producing detergents by agglomeration: Beerse et al., U.S. Do not.

. No. 108,646 (Procter &Gamble); ^ apeci et al., U.S. Pat. Do not. . 366,652 (Procter &Gamble); Hollingsworth and others, patent application Evans et al., U.S. Patent. No. 4,820,441 (Lever); Evans et al., U.S. Patent. No. 4,818,424 (Lever); AJfekinson and others, patent of E.U.A. and 'No. 4,900,466 (Lever); France and other patent of E.U.A. No. 5,576,285 (Procter &Gamble); and Dhalewadika et al., PCT WO96 / 04359 (Unilever).

BRIEF DESCRIPTION OF THE INVENTION The present invention meets the above-mentioned needs in the art by providing a process that produces a low density detergent composition (less than about 600 g / l) directly from a surfactant paste and dry starting detergent ingredients. Basically, the process consists in agglomerating the starting detergent ingredients in a high speed mixer followed by a second high speed mixer. In this manner, the agglomerates formed in the high-speed mixers are agglomerated and dried in a fluid bed dryer wherein a liquid binder is sprayed onto the agglomerates from one or more nozzles at a selected height from the distribution plate. of the fluid bed dryer. The procedure does not use conventional spray drying towers and C, therefore, is more efficient, economical and flexible with respect to the variety of detergent compositions that may be produced in the process. In addition, the process is more sensitive to environmental problems because it does not make use of spray-drying towers that typically emit particles and volatile organic compounds into the atmosphere. As used herein, the term "agglomerates" refers to particles formed by agglomerating granules or particles that typically have a smaller average particle size than the agglomerates formed. As used herein, the term "average particle size" refers to the value of the particle size diameter over 50% of the particles have a larger particle size and less than 50% and the particles have a size of smaller particle. All percentages used herein are expressed as "percent by weight", on an anhydrous basis unless otherwise indicated. According to one aspect of the invention, a method for preparing low density detergent agglomerates is provided.

The method comprises the steps of: (a) agglomerating a slurry of detergent surfactant or precursor thereof and dry starting detergent material in a first high speed mixer to obtain agglomerates; (b) mixing the agglomerates in a second high-speed mixer to obtain formed agglomerates; and (c) feeding the agglomerates formed in a fluid bed drier wherein a binder was foci through a nozzle having a height of about 25 cm to approximation |||||| 60 cm from the plate distribution of the fluid bed dryer so that the formed agglomerates dry and agglomerate to form the low density detergent agglomerates, said density on a scale of about 300 g / l to about 550 g / l. According to another aspect of the invention, a method for preparing low density detergent agglomerates is provided. The process comprises the steps of: (a) agglomerating a slurry of detergent surfactant or precursor thereof and dry starting detergent material in a first high speed mixer to obtain agglomerates; (b) mixing the agglomerates in a second high-speed mixer to obtain formed agglomerates; and (c) feeding the agglomerates formed in a fluid bed dryer wherein sodium silicate is sprayed through a nozzle having a height of about 40 cm to about 60 cm from the bed dryer distribution plate. fluid so that the formed agglomerates dry and agglomerate to form the low density detergent agglomerates, said density on a scale of about 300 g / l to about 550 g / l. Also provided are detergent products made according to any of the embodiments of the processes described in the present invention.

Accordingly, an object of the invention is to provide a process for producing a low density detergent composition from starting detergent ingredients that do not include relatively expensive special ingredients. It is also an object of the invention to provide a process that is more efficient, flexible and economical for facilitating the large scale production of low and high dosage level detergents. These and other concomitant objects, features and advantages of the present invention will become apparent to those skilled in the art upon reading the following detailed description of the preferred embodiment and the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED MODALITY The present invention relates to a process in which low density agglomerates are produced by a three step process, wherein the last step involves a fluid bed dryer containing one or more nozzles positioned at a selected height from the plate. dryer distribution. In this way, the process forms low density, free-flowing detergent agglomerates that can be used alone as the detergent product or as a mixture with conventional spray-dried detergent granules and / or high density detergent agglomerates in a final commercial detergent product. It should be understood that the method described herein may be continuous or intermittent nodes depending on the particular desired application. A major advantage of the present method is that it uses equipment that can operate in a manner different from the parameters of the present process to obtain high density detergent compositions. Therefore, a single large-scale commercial detergent manufacturing facility can be formed to produce high or low density detergent compositions depending on local consumer demand and the inevitable fluctuations between compact and non-compact detergent products. Procedure In the first step of the process, a detergent surfactant paste or precursor thereof as set forth in more detail hereafter and dry starting detergent material are placed and agglomerated in a high speed mixer. Unlike previous processes in this field, the dry starting material may include only those relatively inexpensive detergent materials normally used in modern granular detergent products. Such ingredients include, but are not limited to, builders, fillers, dry surfactants, and fluid auxiliaries. Preferably, the detergency builder includes aluminosilicates, layered crystalline silicates, phosphates, carbonates and mixtures thereof which is the essential dry starting detergent ingredient within the scope of the current process. Relatively expensive materials such as Burkeite i, (N ^ 2S0 * Na2C03) and the various silicas are not necessary to achieve the desired low density agglomerates produced by the process. On the contrary, by selecting the binder and the height of the nozzle through which the binder is sprayed onto the agglomerates in the fluid bed dryer as will be described in greater detail, the present process achieves the desired low density. Furthermore, it is preferable to include from 1% to about 40% by weight of smaller detergent particles or "fine powders" in the first step of the process. This can be conveniently achieved by screening the detergent particles subsequently formed in the fluid bed dryer at a scale of average particle size from about 10 microns to about 150 microns and feeding these "fine powders" again into the high speed mixer. The high speed mixer can be any of a variety of commercially available mixers such as the Lódige CB 30 mixer or a similar brand mixer. These types of mixers basically consist of a horizontal cylinder, static and hollow having a rotating shaft mounted in the central part, around which several knives are attached in the form of rods and blades and have a tip speed of about 5 m / s to about 30 m / s, most preferably around 6 m / s to approximately 26 m / s. Preferably, the shaft rotates at a speed of about 100 rpm at about 2500 rpm, most preferably 300 rpm at about 1600 rpm. Preferably, the average residence time of the detergent ingredients in the high-speed mixer is in the range of about 2 seconds to about 45 seconds, and most preferably from about 5 seconds to about 15 seconds. This average residence time is conveniently measured by dividing the weight of the mixer in a stable state between the product flow (kg / hr). Another suitable mixer is any of the various Flexomix models available from Schugi (The Netherlands) which are vertically placed high speed mixers. This type of mixer preferably operates at a Froude index of about 13 to about 32. See U.S. Pat. do not. 5,149,455 to Jacobs et al (issued September 22, 1992) for a detailed description of this well-known Froude index which is a dimensionless number that can be optimally selected by those skilled in the art. In a preferred embodiment of the process of the invention, a liquid acid precursor of an anionic surfactant is placed with the dry starting detergent material which at least includes a neutralizing agent such as sodium carbonate. The liquid acid surfactant precursor is linear C-i-Mβ alkylbenzenesulfonate surfactant ("HLAS"), although any acid precursor of an anionic surfactant can be used in the process. A preferred embodiment involves feeding a liquid acid precursor of linear C12-14 alkylbenzenesulfonate surfactant with a Cfo-ethoxylated alkyl sulfate ("AS") into the first high-pressure mixer ^ t¡§ || preferably, in a weight ratio of about 5: 1 to about 1: 5, and most preferably, on a scale of about 1: 1 to about 3: 1 (HLAS: AS). The result of said mixture is a "dry neutralization" reaction between the HLAS and the sodium carbonate comprised in the dry starting detergent material, all of the above forms agglomerates. It is preferable to add the HLAS before the addition of other surfactants such as AS or ethoxylated alkyl sulphate ("AES") to ensure optimal mixing and neutralization of HLAS in the first high speed mixer. In the second step of the process, the detergent agglomerates formed in the first step are placed in a second high speed mixer which may be the same piece of equipment that was used in the first step or a different type of high speed mixer. For example, a Lódige CB mixer can be used in the first step, and then a Schugi mixer in the second step. In the second step of the process, the agglomerates are mixed and formed in a controlled manner. In this step, a sufficient amount of binder can be placed to facilitate the formation of agglomeration in the mixer. Typical binders include liquid sodium silicate, a liquid acid precursor of an anionic surfactant such as HLAS, nonionic surfactant, polyethylene glycol or mixtures thereof.

In the next step of the process, the formed agglomerates are placed in a fluid bed dryer where the agglomerates are dried and agglomerated to an average particle size of about 300 microns to about 700 microns, most preferably about 325 microns to approximately 450 microns. The density of the agglomerates formed is from about 300 g / l to about 550 g / l, most preferably from about 350 g / l to about 500 g / l, and still most preferably from about 400 g / l to about 480 g / l. l. All of these densities are generally lower than those of typical detergent compositions formed of dense agglomerates or even more common spray-dried granules. As previously described a binder is preferably added during this step to increase the formation of the desired agglomerates. In this regard, a particularly preferred binder is liquid sodium silicate in an amount of from about 0.1% to about 20% by weight of the final low density composition. The height of the nozzle through which the binder is added is preferably from about 25 cm to about 60 cm, most preferably from about 30 cm to about 60 cm, most preferably from about 40 cm to about 60 cm, and still very preferably 40 cm, from the distribution plate of the fluid bed dryer. Preferably all the nozzles used in the fluid bed drying apparatus have said height arrangement. Unexpectedly, it has been found that by selecting the height of the nozzle within the aforementioned scales, higher density, low density agglomerates are produced in the process from a low density and free flow point of view. Additionally, the benefits of the process in this respect can be increased by keeping the flow of binder spray in the fluid bed from about 0.02 kg / cm2 / hr to about 0.06 kg / cm2 / hr, most preferably about 0.04 kg / cm2 / hr at approximately 0.05 kg / cm2 / hr. Preferably, the air inlet temperature in the fluid bed dryer is from about 100 ° C to about 200 ° C, most preferably from about 110 ° C to about 130 ° C. In addition, the height of the non-fluidized bed in the fluid bed dryer is preferably about 5 cm approximately 20 cm. It has also been found that the benefits of the process can be increased by keeping the fluidized air flow in the fluid bed dryer from about 0.6 kg / m2 / s to about 0.8 kg / m2 / s. It is also beneficial to add the binder simultaneously in one or more locations or in one or more of the steps of the process. For example, the liquid silicate may be added at two locations in the fluid bed dryer, for example, at or near the port of entry and at or near the port of exit. In addition, the average binder drop diameter is from about 20 microns to about 150 microns, a parameter that increases the formation of agglomerates formed i ^ &J & ^ i kS &J8i? ik desired. In addition, the ratio of the average binder droplet diameter to agglomerate particle diameter formed (outside the second high speed mixer) is preferably from about 0.1 to about 0.6. Optionally, the process comprises the addition of the binder to the second high-speed mixer and the fluid bed dryer. It is also beneficial to add the binder simultaneously in one or more locations or in one or more of the steps of the process. For example, the liquid silicate can be added in two locations in the dryer of fluid bed, for example, at or near the port of entry and at or near the port of exit. With respect to the first and second steps of the process, the agglomerates are formed from smaller sizes to larger sized particles having a high degree of intraparticular porosity. The degree of intraparticular porosity is preferably about 20% at about 40%, and most preferably about 25% to about 35%. The intraparticular porosity can be conveniently measured by standard tests of mercury porosimetry. Other optional steps contemplated by the present Processes include the selection of oversize detergent agglomerates in a screening apparatus that can take a variety of forms including but not limited to conventional screens selected for the desired particle size of the finished detergent product. Other steps 17! *! «** optional include the conditioning of the additional detergent agglomerates by the Another optional step of the process comprises finishing the resulting detergent agglomerates by a variety of methods including spraying, and / or mixing other conventional detergent ingredients. For example, the finishing step comprises spraying perfumes, brighteners and enzymes into the finished agglomerates to provide a more complete detergent composition. Such techniques and ingredients are well known in the art.

Detergent surfactant paste or precursor The liquid acid precursor of anionic surfactant is used in the first step of the process, and in optional embodiments, as a liquid binder in the second and / or third essential step of the process. The liquid acid precursor will usually have a viscosity measured at 30 ° C of about 500 cps at about 5000 cps. The liquid acid is a precursor for the anionic surfactants which are described in greater detail below. A detergent surfactant paste can also be used in the process and preferably in the form of a viscous, aqueous paste, although other forms are also contemplated in the invention. The so-called viscous paste has a viscosity from about 5,000 cps to about 100,000 cps, most preferably from about 1,000 cps to about 80,000 cps, and contains at least about 10% water, most preferably at least about of 20% water. Viscosity is measured at 70 ° C and at shear rates of 10 to 100 sec. "1 In addition, if the surfactant paste is used, it will preferably comprise a surfactant in the amounts specified above and the remainder water and other ingredients. Optional detergents The surfactant itself, in the viscous surfactant paste, is preferably selected from anionic, non-ionic, zwitterionic, amphoteric and cationic classes, and compatible mixtures thereof Detersive surfactants useful herein are described in US Pat. US Patent 3,664,961, Norris, issued May 23, 1972, and US Patent 3,919,678, Laug et al., issued December 30, 1975, which are hereby incorporated by reference. Useful cationic surfactants also include those described in US Patent 4,222,905, Cockrell, issued September 16, 1980, and in the US patent 4,239,659, Murphy, issued December 16, 1980, which are also incorporated herein by reference. Of the surfactants, anionics and nonionics are preferred, with anionics being more preferred. Non-limiting examples of preferred anionic surfactants useful in the surfactant paste, or from which the liquid acid precursor described herein is derived, include * ~ > -A "r rf - conventional Cn-Cis-alkylsulfonates (" LAS "), C10-C20 (" AS ") primary alkylsulphates, branched chain and random alkylsulfates (2,3) secondary C < rj- i8 of the formula CH3 (CH2) x (CHOS? 3"M +) CH3 and CH3 (CH2) and (CHOS? 3" M +) CH2CH3> where x and (y +1) are integers of at least about 7, preferably of at least about 9, and M is a cation 510 of solubilization in water, especially sodium, unsaturated sulfates such as oleyl sulfate and C-10-C18 alkylalkoxy sulfates ("AEXS"; especially ethoxysulfates EO 1-7). Optionally, other examples of surfactants useful in the paste of the invention include C 10 -C 18 alkylalkoxycarboxylates (especially the EO 1-5 ethoxycarboxylates), the glycerol ethers of C < | rj-C- | 8- 'the alkyl polyglycosides of C < | rj-Ci8 and its corresponding sulphated polyglycosides, and alpha-sulfonated fatty acid esters of C < | 2_Ci8- If desired, conventional amphoteric and nonionic surfactants such as C12-C18 alkyl ethoxylates ("AE") including the so-called narrow peak alkyl ethoxylates and the CQ-C '' 2 alkylphenolalkoxylates (especially ethoxylates and ethoxy / mixed propoxy), C12-C18 betaines and sulfobetaines ("sultaines"), amine oxides of CJ Q-CI S. and the like, may also be included in the overall compositions. The polyhydroxy fatty acid amides of N- (C-) alkyl may also be used. Typical examples include the N-methylglucamides of C < | 2-C < | 8- See WO 9,206,154. Other surfactants derived from sugar include N-alkoxy polyhydroxy fatty acid amides, such as N- (3-methoxypropyl) glucamide of C- | o-Ci8- The N-propyl to N-hexyl glucamides of C < | 2-C "| 8 can be used for low foam formation Conventional IC soaps Q-C20 can also be used- If high foaming is desired, branched chain C < Rj-Ci6 soaps can be used Mixtures of anionic and nonionic surfactants are especially useful Other conventional useful surfactants are mentioned in standard texts.

Dry detergent material The dry detergent material of the present process preferably comprises a binder and other standard detergent ingredients such as sodium carbonate, especially when a liquid acid precursor of a surfactant is used, since it is required as a neutralizing agent in the first step of the procedure. Therefore, the preferable dry starting detergent material includes sodium carbonate and a phosphate or aluminosilicate binder which is known as an aluminosilicate ion exchange material. A preferred binder is selected from the group consisting of aluminosilicates, layered crystalline silicates, phosphates, carbonates and mixtures thereof. Preferred phosphate binders include sodium tripolyphosphate, tetrasodium pyrophosphate and mixtures thereof. Additional specific examples of inorganic phosphate binders are sodium potassium tripolyphosphate, pyrophosphate, polymeric metaphosphate having a degree of polymerization of about 6 to 21, and orthophosphates. Examples of polyphosphonate binders are the sodium and potassium salts of ethylene diphosphonic acid, the sodium and potassium salts of ethane 1-hydroxy-1,1-diphosphonic acid and the potassium and sodium salts of ethane, 1, 1, 2 -trifosf ionic. Other phosphorus binder 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. The aluminosilicate ion exchange materials used herein as builders preferably have a high calcium ion exchange capacity and a high exchange rate. Without being wished to be limited by theory, it is thought that said high capacity and rate of exchange of calcium ions are a function of several interrelated factors that are derived from the method by which the aluminosilicate ion exchange material is produced. In this regard, the aluminosilicate ion exchange materials used herein are preferably produced in accordance with Corkill et al., U.S. Pat. No. 4,605,509 (Procter &Gamble), the disclosure of which is incorporated herein by reference. Preferably, the aluminosilicate ion exchange material is in the "sodium" form, since the potassium and hydrogen forms of the present aluminosilicate do not exhibit a capacity and a speed of ion exchange as high as the sodium form provides. Additionally, preferably the aluminosilicate ion exchange material is in an over dried form to facilitate the production of crisp detergent agglomerates as described herein. The aluminosilicate ion exchange materials used herein preferably have particle size diameters that optimize their effectiveness as builders. The term "particle size diameter", as used herein, represents the average particle size diameter of a given aluminosilicate ion exchange material determined by conventional analytical techniques, such as microscopic determination and with scanning electron microscopy. (SEM). The preferred particle size diameter of the aluminosilicate is from about 0.1 microns to about 10 microns, more preferably from about 0.5 microns to about 9 microns. Most preferably, the diameter of particle size is from about 1 miera to about 8 micras. Preferably, the aluminosilicate ion exchange material has the formula: Naz [(AIO2) z. (Si? 2) and] xH2O where z and y are integers of at least 6, the molar ratio of z: y is from about 1 to about 5, and x is from about 10 to about 264. Most preferably, the aluminosilicate has the formula: Na12 [(AIO2 ) i2. (Yes? 2) i2] xH2? wherein x is from about 20 to about 30, preferably about 27. These preferred aluminosilicates are commercially available, for example, under the designations Zeolite A, Zeolite B and Zeolite X. Alternatively, naturally occurring aluminosilicate ion exchange materials. or which are synthetically derived and suitable for use herein, can be obtained as described in Krummel et al., US Patent No. 3,985,669, the disclosure of which is incorporated herein by reference. The aluminosilicates used herein are further characterized by their ion exchange capacity which is at least about 200 mg hardness equivalents of CaC 3 / g, calculated on an anhydrous basis, and which is preferably on a scale around from 300 to 352 mg hardness equivalents of CaCO3 / g.

Additionally, the aluminosilicate ion exchange materials of the present are further characterized by their calcium ion exchange rate, which is at least about 2 grains of Ca ++ / 3.785 liters / minute / -gram / 3.785 liters, and more preferably on a scale of about 2 grains of Ca ++ / 3.785 liters / minute / -gram / 3.785 liters to about 6 grains of Ca ++ / 3.785 liters / minute / -gram / 3.785 liters.

Attached detergent ingredients The starting detergent material in the present process can include additional detergent ingredients, and / or any number of additional ingredients can be incorporated into the detergent composition during the subsequent steps of the present process. These adjunct ingredients include other detergency builders, bleaches, bleach activators, foam enhancers, or foam suppressants, anti-rust and anti-corrosion agents, soil suspending agents, soil release agents, germicides, pH adjusting agents, sources of alkalinity without builder, chelating agents, smectite clays, enzymes, 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. Other detergency builders may generally be selected from the various borates, polyhydroxysulfonates, polyacetates, carboxylates, citrates, tartrate mono- and di-succinates, and mixtures thereof. Alkali metal, especially sodium, salts of the above are preferred. Compared with amorphous sodium silicates, the crystallized sodium silicate laminates exhibit a clearly increased calcium and magnesium exchange capacity. In addition, stratified sodium silicates prefer magnesium ions over calcium ions, a feature necessary to ensure that substantially all of the "hardness" is removed from the wash water. However, these layered crystalline sodium silicates are generally more expensive than amorphous silicates, as well as other detergency builders. Consequently, in order to provide an economically feasible laundry detergent, the proportion of the crystalline layered sodium silicates used must be judiciously determined. The layered crystalline sodium silicates suitable for use herein preferably have the formula NaMS¡x? 2x + ?. yH20 wherein M is sodium or hydrogen, x is from about 1.9 to about 4 and y is from about 0 to about 20. Most preferably, the stratified crystalline sodium silicate has the formula NaMSi2? 5.yH2O wherein M is sodium or hydrogen, and y is from about 0 to about 20. These and other stratified sodium silicates are described in Corkill et al., U.S. Pat. No. 4,605,509, previously incorporated herein by reference. Examples of non-phosphorus inorganic builders are tetraborate decahydrate and silicates having a weight ratio of Si 2: metal oxide aLgalinfer between 0.5 to about 10% by weight. 4. 0, preferably from about 1.0 to about 2.4. The non-phosphorus water-soluble organic builders useful herein include the various alkali metal, ammonium and substituted ammonium polylaxes, carboxylates, polycarboxylates and polyhydroxysulfonates. Examples of polyacetate builders and polycarboxylate builders are the sodium, potassium, lithium, ammonium and substituted ammonium salts of ethylenediaminetetraacetic acid, nitrilotriacetic acid, oxydisuccinic acid, methyl acid, benzene polycarboxylic acids, and citric acid. Polycarboxylate polymer detergent builders are described in the US patent. 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, acid mesaconic, fumaric acid, aconitic acid, citraconic acid and methylenemalonic acid. Some of these materials are useful as the water-soluble anionic polymer as described below, but only if they are in intimate admixture 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 the US patent. 4,246,495, issued March 27, 1979 to Crutchfield et al., Which are incorporated herein by reference. These polyacetal carboxylates they can be prepared by bringing together a glyoxylic acid ester and a polymerization initiator under polymerization conditions. The resulting polyacetal carboxylate ester is then 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. 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 U.S.A. 4,663,071, Bush et al., In 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 Bartolotta et al., And 4,136,045, issued January 23, 1979 to Gault et al., Which are 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 to column 7, line 24, incorporated herein by reference. Other builders suitable for use herein are listed in the Baskerville patent, column 13, line 54 to column 16, line 16, and in the U.S. patent. 4,663,071, Bush et al., Issued May 5, 1987, which are incorporated herein by reference. In order to make the present invention more easily understood, reference is made to the following example, which is intended to be illustrative only and not limiting in the scope of the present invention.

EXAMPLE This example illustrates the process of the invention by which a low density agglomerated detergent composition is prepared. A Lódige CB 30 high speed mixer is loaded with a powder mix, mainly sodium carbonate (average particle size 15 microns) and sodium tripolyphosphate ("STPP") with an average particle size of 25 microns. A liquid acid precursor of sodium alkylbenzenesulfonate surfactant (C12H25-C6H4-SO3-H or "HLAS" as discussed below) and a slurry of active C10-18 alkyl ethoxylated alkylsulphate surfactant at 70% (EO = 3, "AES") are also placed in the Lódige CB 30 mixer, where the HLAS is added first. The mixer operates at 1600 rpm and the sodium carbonate STPP, HLAS and AES are formed into agglomerates having an average particle size of about 110 microns after an average residence time in the CB Lódige mixer of about 5 seconds. The agglomerates are then fed to a Schugi high speed mixer (Model # FX160) which operates at 2800 rpm with an average residence time of about 2 seconds. An HLAS binder is placed in the Schugi mixer (model # FX 160) during this step and gives the result in formed agglomerates having an average particle size of about 180 microns. In this way, the agglomerates formed pass through a four-zone fluid bed dryer operating at an air inlet temperature of about 125 ° C and a nozzle height of 40 cm from the distribution plate in the first and fourth fluid bed zone. The flow rate of sodium silicate spray at 0.04 kg / cm2 / hr, the height of the non-fluidized bed is 10 cm, and the flow of fluidized air is 0.6 kg / m2 / s. In the specified particle sizes and sizes, fine powders are also added to the Lódige CB 30 mixer. In the first and fourth zones of the fluid bed dryer, liquid sodium silicate is added in the fluid bed dryer resulting in detergent agglomerates. finished having a density of about 485 g / l and an average particle size of about 360 microns. Unexpectedly, the finished agglomerates have excellent physical properties because they flow freely as shown by their higher grades of cake strength. The composition of the agglomerates is shown in table 1. 2%% .

TABLE 1 (% in weigh) Component 1 LAS (Na) 15.8 AES (EO = 3) 4.7 Sodium carbonate 48.0 STPP 22.7 Sodium silicate 5.5 Water 3.3 100.0 The agglomerates comprise about 14% fine powders (less than 150 microns) that are recycled from the fluidized bed to the Lódige CB 30 that increases the production of the agglomerates produced by the process. Having described the invention in detail, it will be apparent to those skilled in the art that it is possible to make several changes without departing from the scope of the invention, and the invention should not be limited to what was described in the description.

Claims (10)

NOVEPlJP DETO INVENCION *. '* CLAIMS

1. - A process for preparing a low density detergent composition characterized in that it comprises the steps of: a) agglomerating a paste of detergent surfactant or precursor thereof and dry starting detergent material in a first high speed mixer to obtain agglomerates; b) mixing said agglomerates in a second high-speed mixer to obtain formed agglomerates; and c) feeding said agglomerates formed in a fluid bed dryer wherein a binder is sprayed through a nozzle having a height of about 25 cm to 60 cm from the distribution plate of said fluid bed dryer so that said agglomerates formed to dry and agglomerate to form said low density detergent agglomerates, wherein said density is in the range of 300 g / l to 550 g / l.

2. A process according to claim 1, further characterized in that said binder is sodium silicate.

3. A process according to claim 1, further characterized in that said binder has a spray flow of about 0.02 kg / cm2 / hr to 0.06 kg / cm2 / hr. -íl & mmm.

4. - A method according to claim 1, further characterized in that the air inlet temperature of said fluid bed dryer is around 110 ° C to 130 ° C.

5. A process of .. ..ififormity with claim 1, further characterized in that said binder has a drop of average diameter of about 20 microns to 100 microns.

6. A method according to claim 1, further characterized in that said fluidized air flow in said fluid bed dryer is from about 0.6 kg / cm2 / s to 0.8 kg / m2 / s.

7. A process according to claim 1, further characterized in that said step (a) includes agglomerating a liquid acid precursor of linear Cn-iß alkylbenzenesulfonate surfactant and an ethoxylated C10-18 alkyl sulfate surfactant.

8. A method according to claim 1, further characterized in that said binder is added at the inlet and outlet ports of said fluid bed dryer.

9. A method according to claim 1, further characterized in that said height of the nozzle is around 35 cm to 45 cm.

10. A process for preparing a low density detergent composition further characterized in that it comprises the steps of: a) agglomerating a slurry of detergent surfactant or precursor thereof and dry starting detergent material in a first high mixer; It is possible to feed said agglomerates formed in a fluid bed dryer where sodium silicate is sprayed through a nozzle having a height of about 40 cm to 60 cm from the distribution plate. of said fluid bed dryer so that said formed agglomerates dry and agglomerate to form said low density detergent agglomerates, wherein said density is in the range of 300 g / l to 550 g / l.