DE69904236T2 - METHOD FOR PRODUCING A GRANULAR DETERGENT CONTAINING A MODIFIED CARBOXYMETHYLCELLULOSE - Google Patents

Description

Field of the invention

The present invention relates generally to processes for preparing a granular detergent composition. More particularly, the invention relates to processes during which detergent granules or agglomerates are prepared from starting detergent materials, one of which is a modified carboxymethyl cellulose.

Background of the invention

Today's fabrics are made from an ever-increasing variety of materials, and they come in a variety of colors. These different fabric and color combinations present new and difficult washing problems for the consumer. More specifically, consumers want their clothes and other textile items to retain the "new" look or feel that these fabrics have when they are purchased for as long as possible. However, normal washing procedures can slowly destroy the texture of the fabrics and the vibrancy of the color. This slow loss of luster of a fabric is caused in part by the normal wear and tear associated with the use of the fabric, but washing also leaves its mark on the appearance of fabrics.

In an attempt to satisfy consumer desires to slow or, preferably, eliminate the destruction of a fabric's appearance, manufacturers have sought detergent additives that help maintain the appearance of a fabric over its normal life cycle. As new detergent additives are developed, manufacturers must find a way to include the additives in detergent compositions without adversely affecting the physical or chemical properties of the existing composition. That is, an additive that maintains fabric appearance should not reduce the cleaning effectiveness of the detergent, nor should it cause the detergent to clump or otherwise exhibit undesirable physical properties in the eyes of an average consumer. Often, the challenges associated with introducing a new detergent additive can be met by making adjustments to the detergent manufacturing process.

In general, there are two basic types of processes by which detergent granules or powders can be produced. The first type of process involves spray drying an aqueous detergent slurry in a spray drying tower to produce highly porous detergent granules. In the second type of process, the various detergent components are dry mixed, after which they are agglomerated with a binder such as a non-ionic or anionic surfactant. In both processes, the most important factors determining the density of the resulting detergent granules are the density, porosity and surface area of the various starting materials and their respective chemical composition.

There has also been interest in the art in providing processes that increase the density of detergent granules or powders. Particular attention has been paid to densification of spray dried granules by post-spray tower treatment. For example, one attempt involves a batch process in which spray dried or granulated detergent powders containing sodium tripolyphosphate and sodium sulfate are densified and spheronized in a Marumerizer® device. This device comprises a substantially horizontal, roughened, rotatable table positioned within and at the base of a substantially vertical, smooth-walled cylinder. However, this process is essentially a batch process and is therefore less suitable for large-scale production of detergent powders. Recently, other processes have been developed for increasing the density of "post-spray tower" or spray dried detergent granules. Typically, such processes require a first device which pulverizes or crushes the granules, and a second device which increases the density of the pulverized granules by agglomeration. These processes achieve the desired increase in density by treating or densifying "post-spray" or spray-dried granules. The art is also replete with disclosures of processes which result in the agglomeration of detergent compositions. For example, attempts have been made to agglomerate detergent builders by mixing zeolite and/or layered silicates in a mixer to form free-flowing agglomerates.

In addition, the use of surfactants and combinations thereof in detergent compositions has been a long established practice for detergent manufacturers. For example, various anionic surfactants, particularly the alkylbenzene sulfonates, alkyl sulfates and alkyl alkoxy sulfates, and various nonionic surfactants such as alkyl ethoxylates and alkylphenol ethoxylates, are commonly used in detergent formulations. Surfactants have found application as detergent components capable of removing a wide variety of soils and stains. However, detergent manufacturers are continually attempting to improve the detergency properties of detergent compositions by providing new and improved surfactants. A problem frequently associated with anionic surfactants is their sensitivity to cold water and/or hard water. Improved cleaning performance over and beyond current standards, particularly for granular detergent compositions intended to be used under colder wash water conditions and/or in hard water, has been difficult to achieve. Therefore, it would be desirable to to provide a process for preparing a detergent composition which exhibits improved cleaning performance against a wide variety of soils and stains.

Accordingly, there remains a need in the art for a process which produces a granular and/or agglomerated detergent composition from starting detergent ingredients including a surfactant which exhibits improved protection for fabric appearance without any loss in cleaning performance. There also remains a need for such a process which is more efficient and economical to facilitate the large-scale production of low dosage or compact detergents.

Background of the field

The following references relate to the compaction of spray dried granules: Appel et al., US Patent No. 5,133,924 (Lever); Bortolotti et al., US Patent 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 relate to the manufacture of detergents by agglomeration: Beerse et al., US Patent No. 5,108,646 (Procter &Gamble); Hollingsworth et al., European Patent Application 351,937 (Unilever); Swatling et al., US Patent No. 5,205,958; and Capeci et al., U.S. Patent No. 5,366,652 (Procter & Gamble).

Summary of the invention

The present invention meets the above-mentioned needs in the art by providing a process for continuously producing detergent agglomerates comprising the steps of: (A) continuously mixing a liquid binder and dry detergent materials in a high speed mixer/densifier to obtain detergent agglomerates, the ratio of liquid binder to dry detergent material being from 1:10 to 10:1, wherein the dry detergent materials comprise modified carboxymethyl cellulose; (B) optionally mixing the detergent agglomerates in a moderate speed mixer/densifier to further densify and agglomerate the detergent agglomerates; and (C) drying the detergent agglomerates so as to increase their density. In a preferred embodiment of this invention, the dry detergent materials consist essentially of modified carboxymethyl cellulose.

In another preferred aspect of this invention, the liquid binder comprises water and a polymer selected from the group consisting of dye transfer agents, polyamines, homopolymers and copolymers of polyacrylates, homopolymers and copolymers of polyacrylamides, homopolymers and copolymers of polyvinyl alcohol, homopolymers and copolymers of polyvinylpyrrolidone, polymaleates, aliphatic polyesters, natural proteins, synthetic non-crystalline linen polyamino acids, water soluble nylons, polyethylene glycol, polyacrylate, and mixtures thereof. Even more preferably, the liquid binder comprises a polymer selected from the group consisting of polyvinyl-N-oxide, a copolymer of epichlorohydrin and a cyclic amine group, and mixtures thereof.

A preferred aspect of the invention includes the use of a surfactant paste in addition to the liquid polymer-based binder. The paste includes surfactants selected from branched and linear, anionic, nonionic, zwitterionic, ampholytic and cationic classes, and compatible mixtures thereof. Even more preferably, the surfactant paste is selected from the group consisting of linear straight chain alkylbenzene sulfonates wherein the average number of carbon atoms in the alkyl group is 11 to 13, abbreviated as C11-13 LAS, and sodium ethoxysulfate based on a biodegradable synthetic or natural C12/14 primary alcohol ethoxylate prepared with nominally 3 moles of ethylene oxide.

In another embodiment of this invention, a process is provided for preparing a high density detergent composition wherein additional detergent ingredients are formulated into separate agglomerates or granules and then mixed with the modified carboxymethylcellulose-containing agglomerates defined above. More specifically, the second detergent agglomerates can be prepared by a process comprising the steps of: (A) continuously mixing a detergent surfactant paste and additional dry detergent materials in a high speed mixer/densifier to obtain second detergent agglomerates, the ratio of surfactant paste to additional dry detergent material being 1:10 to 10:1 ; (B) optionally mixing the second detergent agglomerates in a moderate speed mixer/densifier to further increase their density; and (C) drying the second detergent agglomerates to further increase their density. The second detergent agglomerates can then be mixed with the first detergent agglomerates to form the high density detergent composition. In another aspect of this embodiment, the surfactant paste can be replaced with or supplemented with an acid precursor of an anionic surfactant and additional dry detergent materials containing an alkaline inorganic material capable of neutralizing the acid precursor.

In addition, detergent granules can be mixed with the modified carboxymethyl cellulose-containing agglomerates defined above to form a high density detergent composition. These granules can be formed by spray drying an aqueous slurry containing additional detergent ingredients to form spray dried granules. The granules and detergent agglomerates can then be mixed together to form the high density detergent composition.

It has surprisingly been found that certain modified carboxymethyl cellulose materials provide fabric appearance benefits. Unfortunately, the modified carboxymethyl cellulose materials are sometimes provided as a sticky powder which, when added to a detergent composition, can cause the resulting detergent agglomerates to also be sticky. Sticky agglomerates often cause clumps in the detergent composition, which is very negative for the consumer. In addition to stickiness, the inventors have also found that these modified carboxymethyl cellulose materials are not always sufficiently dispersed, resulting in reduced performance and also localized residues of the material in the washing machine and on the fabrics.

Furthermore, the inventors also discovered that other detergent ingredients can become entrapped in the cellulosic material, causing further residue problems and reduced performance of these other ingredients. The stickiness and insufficient dispersibility of the modified carboxymethyl cellulose and their adverse effect on the detergent composition can be counteracted by the processing conditions and ingredients defined herein.

Accordingly, it is an object of the present invention to provide a process for producing a granular and/or agglomerated detergent composition directly from starting detergent ingredients including a surfactant and a modified carboxymethylcellulose, having improved fabric integrity performance. It is also an object of the invention to provide such a process which is not limited by unnecessary process parameters so that large-scale production of low dosage or compact detergents is more economical and efficient. These and other objects, features and related advantages of the present invention will become apparent to those skilled in the art from a reading of the following detailed description of the invention and the appended claims.

Detailed description of the invention

The present process is applied in the preparation of detergent compositions wherein two separate agglomerate particles are prepared. A first agglomerate is prepared using a liquid binder comprising a surfactant mixture selected from the group of LAS, preferably C11-13 LAS, or sodium ethoxysulfate, the ethoxysulfate preferably being based on a biodegradable synthetic or natural primary C12/14 alcohol ethoxylate prepared with nominally 3 moles of ethylene oxide, and mixtures thereof; this liquid binder is used in combination with a polymer selected from the group consisting of a copolymer of epichlorohydrin and a cyclic amine group or polyvinyl-N-oxide, and mixtures thereof in combination with dry detergent materials including a modified carboxymethylcellulose. A second agglomerate is prepared using a surfactant paste and dry starting materials which do not include modified carboxymethylcellulose. The two separate agglomerates are mixed to form a detergent composition which is free-flowing. In addition, the separate detergent particles of the invention can be formed by spray drying techniques which may include further processing of the "post-spray" detergent granules. By "post-spray" detergent granules is meant those detergent granules which have been produced by a conventional spray drying tower or similar apparatus.

Dry detergent materials

The compositions of the invention contain, in addition to a modified carboxymethyl cellulose material, at least one suitable additional dry detergent ingredient which is preferably included in the detergent composition. The resulting detergent composition comprises from 0.01 to 4%, more preferably from 0.05 to 2%, and most preferably from 0.1 to 1% by weight of the modified carboxymethyl cellulose.

The additional dry detergent ingredient is preferably selected from the group consisting of builders, enzymes, bleaches, bleach activators, suds suppressors, soil release agents, brighteners, dulting agents, hydrotropes, dyes, pigments, polymeric dispersants, pH control agents, complexing agents, processing aids, crystallization aids, and mixtures thereof. The following disclosure of modified carboxymethylcellulose materials and additional detergent ingredients and mixtures thereof for use in the compositions herein is representative of the detergent ingredients but is not intended to be limiting.

As discussed above, certain modified carboxymethylcellulose materials, which are in the form of cellulose-based polymers or oligomers, can provide significant and unexpected cleaning benefits when added to a laundry composition. But these materials can also alleviate certain processing problems for granular detergent manufacturers. The modified carboxymethylcellulose materials suitable for use in laundry processes and which provide the desired fabric appearance and integrity benefits can be characterized by the following general formula:

wherein each R is selected from the group consisting of R₂, Rc and

wherein:

- each R₂ is independently selected from the group consisting of H and C₁-C₄ alkyl;

- each Rc

wherein each Z is independently selected from the group consisting of M, R₂, Rc and RH;

- each RH is independently selected from the group consisting of C5 -C20 alkyl, C5 -C7 cycloalkyl, C7 -C20 alkylaryl, C7 -C20 arylalkyl, substituted alkyl, hydroxyalkyl, C1 -C20 alkoxy-2-hydroxyalkyl, C7 -C20 alkylaryloxy-2-hydroxyalkyl, (R4 )2 N-alkyl, (R4 )2 N -2-Hydroxyalkyl, (R4 )3 N-alkyl, (R4 )3 N-2-hydroxyalkyl, C6 -C12 -aryloxy-2-hydroxyalkyl

- each R4 is independently selected from the group consisting of H, C1-C20 alkyl, C5-C7 cycloalkyl, C7-C20 alkylaryl, C7-C20 arylalkyl, aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl, piperidinoalkyl, morpholinoalkyl, cycloalkylaminoalkyl and hydroxyalkyl;

- each R₅ is independently selected from the group consisting of H, C₁-C₂₀ alkyl, C₅-C₇ cycloalkyl, C₇-C₂₀ alkylaryl, C₇-C₂₀ arylalkyl, substituted alkyl, hydroxyalkyl, (R₄)₂N-alkyl and (R₄)₃N-alkyl;

wherein:

M is a suitable cation selected from the group consisting of Na, K, 1/2Ca and 1/2Mg;

each x is 0 to 5;

each y is 1 to 5; and

provided that

- the degree of substitution for the group RH is between about 0.001 and 0.1, more preferably between about 0.005 and 0.05 and most preferably between about 0.01 and 0.05;

- the degree of substitution for the group Rc, wherein Z is H or M, is between about 0.2 and 2.0, more preferably between about 0.3 and 1.0, and most preferably between about 0.4 and 0.7;

- if any RH group carries a positive charge, this is balanced by a suitable anion; and

- two R₄ groups on the same nitrogen can together form a ring structure, selected from the group consisting of piperidine and morpholine.

Preferably, the carboxymethylcellulose is modified with an ester linkage, ether linkage, or combinations thereof. Modified carboxymethylcellulose materials suitable for use in the present invention are described in more detail in two applications entitled "Laundry Detergent Compositions With Cellulosic Based Polymers to Provide Appearance and Integrity Benefits to Fabric Laundered Therewith," WO 99/14245 and WO 99/14235. These two applications were filed with the PCT on September 15, 1998 in the names of Jennifer A. Leupin et al.

One or more builders may be used to further enhance the performance of the compositions described herein. The builder may, for example, be selected from the group consisting of aluminosilicates, crystalline layered silicates, MAP zeolites, citrates, amorphous silicates, polycarboxylates, sodium carbonates, and mixtures thereof. The sodium carbonate component may serve as an inorganic alkaline material when a liquid acid precursor of the branched medium chain surfactant is used. Other suitable additional builders are described below.

Preferred builders include aluminosilicate ion exchange materials and sodium carbonate. The aluminosilicate ion exchange materials used as detergent builders herein preferably have both a high calcium ion exchange capacity and a high exchange rate. Without being bound by theory, it is believed that such high calcium ion exchange rate and capacity is a function of several interrelated factors that depend on the process by which the aluminosilicate ion exchange material is prepared. In this regard, the aluminosilicate ion exchange materials used herein are preferably prepared according to Corkill et al., U.S. Patent No. 4,605,509 (Procter & Gamble).

Preferably, the aluminosilicate ion exchange material is in the "sodium" form because the potassium and hydrogen forms of the present aluminosilicate do not exhibit as high an exchange rate and capacity as provided by the sodium form. In addition, the aluminosilicate ion exchange material is preferably in an overdried form to facilitate the preparation of granular detergent agglomerates as described herein. The aluminosilicate ion exchange materials used herein preferably have particle size diameters which optimize their effectiveness as detergent builders. The term "particle size diameter" as used herein as used herein represents the average particle size diameter of a particular aluminosilicate ion exchange material as determined by conventional analytical techniques such as microscopic determination and scanning electron microscope (SEM). The preferred particle size diameter of the aluminosilicate is 0.1 micron to 10 microns, more preferably 0.5 micron to 9 microns. Most preferably the particle size diameter is 1 micron to 8 microns.

Preferably, the aluminosilicate ion exchange material has the formula :

Naz[(AlO2 )z(SiO2 )y]xH2 O

wherein z and y are integers of at least 6, the molar ratio of z to y is 1 to 5, and x is 10 to 264. More preferably, the aluminosilicate has the formula:

Na 12 [(AlO 2 ) 12 (SiO 2 ) 12 ]xH 2 O

where x is 20 to 30, preferably about 27. These preferred aluminosilicates are commercially available, for example, under the names Zeolite A, Zeolite B, and Zeolite X. Alternatively, naturally occurring or synthetically derived aluminosilicate ion exchange materials suitable for use herein can be prepared as described in Krummel et al., U.S. Patent No. 3,985,669.

The aluminosilicates used herein are further characterized by their ion exchange capacity which is at least about 200 mg equivalents of CaCO3 hardness/gram, calculated on an anhydrous basis, and which is preferably in the range of about 300 to 352 mg equivalents of CaCO3 hardness/gram. In addition, the present aluminosilicate ion exchange materials are still further characterized by their calcium ion exchange rate which is at least about 2 grains Ca++/gallon/minute/gram/gallon, and more preferably in the range of 2 grains Ca++/gallon/minute/gram/gallon to 6 grains Ca++/gallon/minute/gram/gallon.

Liquid binder

To form the desired agglomerates of the present invention, the dry starting materials are mixed with a liquid binder. A binder is added for the purpose of enhancing agglomeration by providing a "binding" or "sticking" agent for the detergent components. The preferred liquid binder for use in this invention comprises water, a surfactant paste and a polymer. The paste includes surfactants selected from branched and linear, anionic, nonionic, zwitterionic, ampholytic and cationic classes, as well as compatible mixtures thereof. The viscosity, rheology and chemical composition of the surfactant pastes are described in more detail below. The polymer is selected from the group consisting of dye transfer agents, polyamines, homopolymers and copolymers of polyacrylates, homopolymers and copolymers of polyacrylamides, homopolymers and copolymers of polyvinyl alcohol. Homopolymers and copolymers of polyvinylpyrrolidone, polymaleates, aliphatic polyesters, natural proteins, synthetic non-crystalline polyamino acids, water-soluble nylons, polyethylene glycol, polyacrylate and mixtures thereof. The detergent compositions prepared with the agglomerates of the invention preferably comprise from 0.01 to 4%, more preferably from 0.05 to 2% and most preferably from 0.1 to 1% by weight of the liquid binder.

Preferably, the surfactant paste is selected from the group consisting of linear straight chain alkylbenzenesulfonates, preferably linear straight chain alkylbenzenesulfonates wherein the average number of carbon atoms in the alkyl group is 11 to 13 (abbreviated as C11-13 LAS), sodium ethoxysulfate, preferably based on a biodegradable, synthetic or natural, primary C12/14 alcohol ethoxylate prepared with nominally 3 moles of ethylene oxide, and mixtures thereof.

Preferably, the dye transfer agent is a polyvinyl N-oxide such as poly-(4-vinylpyridine N-oxide), "PVNO". Copolymers of N-vinylpyrrolidone and N-vinylimidazole are also acceptable for use herein. Polyvinyl N-oxide materials are disclosed in U.S. Patent No. 5,804,543, which issued September 8, 1998 to Wertz and Panandiker.

Additional preferred liquid binders for use in the present invention are polyamines, and even more preferred are copolymers of epichlorohydrin and a cyclic amine group. Descriptions and examples of the preferred polyamines for use in the present invention can be found in the following PCT patent applications: WO 99/14300, WO 99/14299 and WO 99/14301, all three of which were filed internationally on September 15, 1998.

Optionally, the method includes the step of spraying an additional binder into one or both of the mixer/densifiers. The additional binder is preferably selected from the group consisting of water, anionic surfactants, nonionic surfactants, polyethylene glycol, polyvinylpyrrolidone, polyacrylates, citric acid, and mixtures thereof. Other suitable binder materials, including those listed herein, are described in Beerse et al., U.S. Patent No. 5,108,646 (Procter & Gamble Co.).

Surfactant paste

The viscoelastic surfactant paste used herein exhibits viscoelastic fluid properties which can be described by a commonly used mathematical model that takes into account the shear thinning nature of the paste. The mathematical model is referred to as the power law model and is described by the following relationship:

σ = Kγn

where σ = shear stress (dynes/cm²), K = consistency (poise. secn-1), γ = shear rate (sec⊃min;¹) and n = index fraction (dimensionless). The index fraction n varies from 0 to 1. The closer n is to 0, the more structurally viscous the fluid is. The closer n is to 1, the closer the fluid is to simple Newtonian behavior, i.e. constant viscosity behavior. K can be interpreted as the apparent viscosity at a shear rate of 1 sec⊃min;¹.

In this context, the viscoelastic surfactant paste used in the process has a consistency K at 70°C of 50,000 to 450,000 cPoise. secn-1 (500 to 2,500 poise. secn-1), more preferably 100,000 to 195,000 cPoise. secn-1 (1,000 to 1,950 poise. secn-1) and most preferably 120,000 to 180,000 cPoise. secn-1 (1,200 to 1,800 poise. secn-1). Preferably, the surfactant paste has a shear index n of 0.05 to 0.25, more preferably 0.08 to 0.20 and most preferably 0.10 to 0.15.

The paste includes surfactants selected from branched and linear, anionic, nonionic, zwitterionic, ampholytic and cationic classes, and compatible mixtures thereof. Detergent surfactants useful herein are described in US Patent 3,664,961, Norris, issued May 23, 1972, and in US Patent 3,919,678, Laughlin et al., issued December 30, 1975. Useful cationic surfactants also include those described in US Patent 4,222,905, Cockrell, issued September 16, 1980, and in US Patent 4,239,659, Murphy, issued December 16, 1980.

The following examples are representative examples of detergent surfactants useful in the present surfactant paste. Water-soluble salts of the higher fatty acids, i.e., "soaps," are useful anionic surfactants in the compositions herein. These include alkali metal soaps such as the sodium, potassium, ammonium and alkylolammonium salts of higher fatty acids containing 8 to 24 carbon atoms and preferably 12 to 18 carbon atoms. Soaps can be made by the direct saponification of fats and oils or by the neutralization of free fatty acids. Particularly useful are the sodium and potassium salts of the mixtures of fatty acids derived from coconut oil and tallow, i.e., sodium or potassium tallow and coconut soap.

Additional anionic surfactants suitable for use herein include the water-soluble salts, preferably the alkali metal, ammonium and alkylolammonium salts, of organic sulfuric acid reaction products having in their molecular structure a straight chain alkyl group containing 10 to 20 carbon atoms and a sulfonic acid or sulfuric acid ester group. (Included in the term "alkyl" is the alkyl portion of acyl group.) Examples of this group of synthetic surfactants are the sodium and potassium alkyl sulfates, particularly those obtained by sulfating the higher alcohols (C8-C18 carbon atoms), such as those prepared by reducing the glycerides of tallow or coconut oil; and the sodium and potassium alkylbenzenesulfonates wherein the alkyl group is 9 to 15 carbon atoms in a straight chain, e.g., those of the type described in U.S. Patents 2,220,099 and 2,477,383. Particularly useful are linear straight chain alkylbenzenesulfonates wherein the average number of carbon atoms in the alkyl group is 11 to 3, abbreviated as C₁₁₋₁₃ LAS.

Other anionic surfactants suitable for use herein are the sodium alkyl glyceryl ether sulfonates, particularly those higher alcohol ethers derived from tallow or coconut oil; sodium coconut oil fatty acid monoglyceride sulfonates and sulfates; sodium or potassium salts of ethylene oxide per molecule and wherein the alkyl groups contain 8 to 12 carbon atoms; and sodium or potassium salts of alkyl ethylene oxide ether sulfates containing 1 to 10 units of ethylene oxide per molecule and where the alkyl groups contain 10 to 20 carbon atoms.

Additionally, suitable anionic surfactants include the water-soluble salts of esters of alpha-sulfonated fatty acids containing 6 to 20 carbon atoms in the fatty acid group and 1 to 10 carbon atoms in the ester group; water-soluble salts of 2-acyloxyalkane-1-sulfonic acids containing 2 to 9 carbon atoms in the acyl group and 9 to 23 carbon atoms in the alkane group; alkyl ether sulfates containing 10 to 20 carbon atoms in the alkyl group and 1 to 30 moles of ethylene oxide; water-soluble salts of olefin and paraffin sulfonates containing 12 to 20 carbon atoms; and beta-alkyloxyalkanesulfonates containing 1 to 3 carbon atoms in the alkyl group and 8 to 20 carbon atoms in the alkane group.

Preferred additional anionic surfactants are C10-18 linear alkylbenzene sulfonate and C10-18 alkyl sulfate. Optionally, the low moisture (less than about 25% water) alkyl sulfate paste can be the only ingredient in the surfactant paste. Most preferred are C10-18 alkyl sulfates, linear or branched, and any primary, secondary or tertiary species. A preferred embodiment of the present invention is one wherein the surfactant paste comprises 20 to 40% of a mixture of sodium linear C10-13 alkylbenzenesulfonate and sodium C12-16 alkyl sulfate in a weight ratio of about 2:1 to 1:2. Another preferred embodiment of the detergent composition includes a mixture of C10-18 alkyl sulfate and C10-18 alkyl ethoxysulfate in a weight ratio of about 80:20.

Water-soluble nonionic surfactants are also useful in the present invention. Such nonionic materials include compounds prepared by the condensation of alkylene oxide groups (hydrophilic in nature) with an organic hydrophobic compound, which may be aliphatic or alkyl aromatic in nature. The length of the polyoxyalkylene group condensed with any particular hydrophobic group can be readily adjusted to obtain a water-soluble compound having the desired degree of balance between hydrophilic and hydrophobic elements.

Suitable nonionic surfactants include the polyethylene oxide condensates of alkylphenols, e.g., the condensation products of alkylphenols with an alkyl group containing 6 to 15 carbon atoms in either a straight chain or branched chain configuration, with 3 to 12 moles of ethylene oxide per mole of alkylphenol. Included are the water-soluble and water-dispersible condensation products of aliphatic alcohols containing 8 to 22 carbon atoms in either a straight chain or branched chain configuration, with 3 to 12 moles of ethylene oxide per mole of alcohol.

Another group of nonionic surfactants suitable for use herein are semipolar nonionic surfactants which include water-soluble amine oxides containing one alkyl group of 10 to 18 carbon atoms and two groups selected from the group consisting of alkyl and hydroxyalkyl groups of 1 to 3 carbon atoms; water-soluble phosphine oxides containing one alkyl group of 10 to 18 carbon atoms and two groups selected from the group consisting of alkyl groups and hydroxyalkyl groups of 1 to 3 carbon atoms; and water-soluble sulfoxides containing one alkyl group of 10 to 18 carbon atoms and one group selected from the group consisting of alkyl and hydroxyalkyl groups of 1 to 3 carbon atoms.

Preferred nonionic surfactants have the formula R¹(OC₂H₄)nOH, where R¹ is a C₁₀-C₁₆ alkyl group or a C₈-C₁₂ alkylphenyl group, and n is 3 to about 80. Particularly preferred are the condensation products of C₁₂-C₁₅ alcohols with 5 to 20 moles of ethylene oxide per mole of alcohol, e.g. a C₁₂-C₁₃ alcohol condensed with about 6.5 moles of ethylene oxide per mole of alcohol.

Other suitable nonionic surfactants include polyhydroxy fatty acid amides. Examples are N-methyl-N-1-deoxyglucitylcocoamide and N-methyl-N-1-deoxyglucityloleamide. Methods for preparing polyhydroxy fatty acid amides are known and can be found in Wilson, U.S. Patent No. 2,965,576, and Schwartz, U.S. Patent No. 2,703,798.

Ampholytic surfactants include derivatives of aliphatic derivatives of heterocyclic secondary and tertiary amines, wherein the aliphatic group may be straight chain or branched, and wherein one of the aliphatic substituents contains 8 to 18 carbon atoms, and at least one aliphatic substituent contains an anionic water-solubilizable group.

Zwitterionic surfactants include derivatives of aliphatic quaternary ammonium, phosphonium and sulfonium compounds wherein one of the aliphatic substituents contains 8 to 18 carbon atoms.

Cationic surfactants may also be included in the invention. Cationic surfactants include a wide variety of compounds characterized by having one or more organic hydrophobic groups in the cation and generally a quaternary nitrogen associated with an acid residue, Pentavalent nitrogen ring compounds may also be considered quaternary nitrogen compounds. Suitable anions are halides, methyl sulfate and hydroxide. Tertiary amines may exhibit properties similar to cationic surfactants at wash solution pH values of less than about 8.5. A more complete disclosure of these and other cationic surfactants useful herein may be found in U.S. Patent 4,228,044, Cambre, issued October 14, 1980.

Cationic surfactants are often used in detergent compositions to provide fabric softening and/or antistatic benefits. Antistatic agents which provide some softening benefit and which are preferred herein are the quaternary ammonium salts described in U.S. Patent 3,936,537, Baskerville Jr. et al., issued February 3, 1976.

Agglomeration process

As used herein, the term "agglomerates" refers to particles formed by progressive agglomeration of starting detergent ingredients (particles) which typically have a smaller average particle size than the agglomerates formed. All percentages and ratios used herein are expressed as percentages by weight (anhydrous basis) unless otherwise specified. All viscosities reported herein are measured at 70°C (±5°C) and at shear rates of about 10 to 100 sec-1.

In the first step of the process, the invention requires the continuous mixing in a high speed mixer/densifier of several streams of starting detergent ingredients including a liquid binder comprising a mixture of a liquid polymer and a surfactant paste. Dry detergent materials, which may include a modified carboxymethylcellulose material, may also be continuously added to the high speed mixer/densifier.

In one embodiment of the process, the dry starting detergent material comprises 10 to 50%, preferably 15 to 45%, and most preferably 20 to 40%, of an aluminosilicate or zeolite builder, and 10 to 40%, preferably 15 to 30%, and most preferably 15 to 25%, of a sodium carbonate. It should be understood that additional starting detergent ingredients, several of which are described below, can be mixed into the high speed mixer/densifier without departing from the scope of the invention.

In another embodiment of the process, the dry starting detergent material comprises 10 to 50%, preferably 15 to 45%, and most preferably 20 to 40% of an aluminosilicate or zeolite builder, and 10 to 40%, preferably 15 to 30%, and most preferably 15 to 25% of an ester-modified carboxymethyl cellulose. It should be understood that additional starting detergent ingredients, several of which are described below, may be used in the high speed mixer/compressor without departing from the scope of the invention.

However, it has been found that when the liquid binder comprising a liquid polymer and a surfactant paste and the dry starting detergent material are continuously mixed in the ratio ranges described herein, the desired free-flowing, granular, high density detergent composition is produced. Preferably, the ratio of the surfactant paste or liquid binder to the dry starting detergent material is 1:10 to 10:1, more preferably 1:4 to 4:1 and most preferably 2:1 to 2:3.

It has also been found that the first processing step can be successfully completed under the process parameters described herein in a high speed mixer/densifier, which is preferably a Lödige CB mixer or similar brand mixer. These types of mixers consist essentially of a horizontal, hollow, stationary cylinder with a centrally inserted rotating shaft around which a plurality of plow-like blades are mounted. Preferably, the shaft rotates at a speed of from 300 rpm to 2,500 rpm, more preferably 400 rpm to 1,600 rpm. Preferably, the average residence time of the detergent ingredients in the high speed mixer/densifier is preferably in the range of from 2 seconds to 45 seconds, and most preferably from 5 seconds to 15 seconds. The average residence time can be measured appropriately and accurately by dividing the breakaway weight of the mixer/compactor by the throughput (e.g. kg/h).

The resulting detergent agglomerates formed in the high speed mixer/densifier are then fed into a low or moderate speed mixer/densifier during which further agglomeration and densification continues. This particular moderate speed mixer/densifier used in the present process should include liquid distribution and agglomeration aids so that both techniques can be continued simultaneously. It is preferred that the moderate speed mixer/densifier is, for example, a Lödige KM (Plowshare Mixer, Drais® K-T 160 Mixer or similar brand mixer. The speed of the centrally rotating main shaft is 30 to 160 rpm, more preferably 50 to 100 rpm. The average residence time in the moderate speed mixer/densifier is preferably 0.25 minutes to 15 minutes, most preferably the residence time is 0.5 to 10 minutes. This average residence time can also be conveniently and accurately determined by dividing the breakaway weight force of the mixer/densifier at steady state by the throughput (e.g. kg/h). Liquid distribution is achieved by cutters, generally smaller in size than the rotating shaft, which preferably operate at about 3,600 rpm.

According to the invention, the high speed mixer/densifier and the moderate speed mixer/densifier in combination preferably transfer the necessary amount of energy to form the desired agglomerates. More preferably, the present process transfers 5 x 10¹⁰ erg/kg to 2 x 10¹² erg/kg at a rate of 3 x 10⁸ erg/kg-sec to 3 x 10⁹⁰ erg/kg-sec to form free-flowing high density detergent agglomerates. The energy input and the feed rate can be determined by calculations from power measurements for the moderate speed mixer/densifier with and without granules, the residence time of the granules in the mixer/densifier and the mass of the granules in the mixer/densifier. Such calculations are clearly within the skill of the art.

Thereafter, the detergent agglomerates are dried in a fluid bed dryer or a similar device. The density of the resulting detergent agglomerates leaving the fluid bed dryer is at least 400 g/l, more preferably 500 g/l to 600 g/l.

The particle porosity of the resulting detergent agglomerates of the composition is preferably in the range of 5 to 20%, more preferably about 10%. As will be readily appreciated by those skilled in the art, a low porosity detergent agglomerate provides a dense or low dosage detergent product, which is the primary focus of the present process. Additionally, a characteristic of dense or compacted detergent agglomerates is relative particle size. The present process typically provides agglomerates with an average particle size of 400 microns to 700 microns, and more preferably 475 microns to 600 microns. As used herein, the term "average particle size" refers to individual agglomerates and not to individual particles or detergent granules. The combination of the above-mentioned porosity and particle size yields agglomerates with density values of 600 g/L and higher. Such a feature is particularly useful in the manufacture of low-dose laundry detergents as well as other granular compositions such as dishwashing detergent compositions.

Optional process steps

In an optional step of the present process, the detergent agglomerates exiting the fluid bed dryer are further conditioned by cooling the agglomerates in a flotation cooler or similar device as is well known in the art. Another optional process step comprises adding a coating agent to improve flowability and/or minimize over-agglomeration of the detergent composition at one or more of the following points in the present process: (1) the coating agent can be added immediately after the flotation cooler; (2) the coating agent can be added between the fluid bed dryer and the flotation cooler; (3) the coating agent can be added between the fluid bed dryer and the moderate speed mixer/densifier; and/or (4) the coating agent can be added directly to the moderate speed mixer/densifier and the fluid bed dryer. It should be understood that the coating agent can be added in any one or a combination of streams, see Capeci et al., U.S. Patent 5,516,448, issued May 14, 1996, and Capeci et al., U.S. Patent 5,489,392, issued February 6, 1996.

The coating agent is preferably selected from the group consisting of aluminosilicates, silicates, carbonates and mixtures thereof. However, the coating agent may be one or more combinations of the builder material, aluminosilicates, carbonates or silicates. The coating agent not only increases the free flowability of the resulting detergent composition, which is desirable to consumers in that it allows for easy scooping out of the detergent during use, but also serves to control agglomeration by preventing or minimizing overagglomeration, especially when added directly to the moderate speed mixer/densifier. Those skilled in the art are well aware that overagglomeration can result in very undesirable flow characteristics and aesthetic properties of the finished detergent product.

Other optional steps contemplated by the present process include screening the oversized detergent agglomerates in a screening device which may take a variety of forms, including, but not limited to, conventional screens selected according to the desired particle size of the finished detergent product. Other optional steps include conditioning the detergent agglomerates by subjecting the agglomerates to additional drying.

Another optional step of the present process requires compounding the resulting detergent agglomerates by a variety of methods, including atomization and/or admixture of other conventional detergent ingredients. This step includes, for example, spraying fragrances, brighteners and enzymes onto the finished agglomerates to provide a more complete detergent composition. Such techniques and ingredients are well known in the art.

Spray drying process

One or more spray drying techniques may be used alone or in combination with the agglomeration processes mentioned above to prepare detergent compositions according to the invention. One or more spray drying towers may be used to prepare granular laundry detergents, often having a density of about 500 g/l or less. In this process, an aqueous slurry of various heat stable ingredients in the final detergent composition is prepared by passage through a spray drying tower using The granules are formed into homogeneous granules using conventional techniques at temperatures of 175ºC to 225ºC. If spray drying is used as part of the overall process herein, additional processing steps as described herein may optionally be used to obtain the density level (ie > 650 g/l) required for modern, compact, low-dose detergent products.

For example, spray dried granules from a tower can be further densified by introducing a liquid such as water or a non-ionic surfactant into the pores of the granules and/or subjecting them to one or more high speed mixers/densifiers. A suitable high speed mixer/densifier for this process is the "Lödige CB 30" or "Lödige CB 30 Recycler" mentioned above, which comprises a stationary cylindrical mixing drum having a central rotating shaft to which mixing arms/cutters are mounted. In use, the ingredients for the detergent composition are introduced into the drum and the shaft/blade assembly is rotated at speeds in the range of 100-2500 rpm to provide thorough mixing/densification. See Jacobs et al., U.S. Patent 5,149,455, issued September 22, 1992. Other such apparatus includes those sold under the trade name "Shugi Granulator" and under the trade name "Drais K-TTP 80."

Another process step which can be used to further densify spray dried granules involves grinding and agglomerating or reforming the spray dried granules in a moderate speed mixer/densifier to obtain particles with a lower porosity. Apparatus such as the above mentioned "Lödige KM" (series 300 or 600) or "Lödige Ploughshare" mixer/densifiers are suitable for this process step. Another useful apparatus includes the device available under the trade name "Drais K-T 160". This process step, which uses a moderate speed mixer/densifier (e.g. Lödige KM), can be used alone or in sequence with the above mentioned high speed mixer/densifier (e.g. Lödige CB) to achieve the desired density. Other types of apparatus for preparing granules useful herein include the apparatus disclosed in U.S. Patent 2,306,898 to Heller G.L., December 29, 1942.

Although it may be more convenient to use the high speed mixer/densifier followed by the low speed mixer/densifier, the reverse sequential mixer/densifier arrangement is also included in the present invention. Any one or combination of various parameters, including residence times in the mixer/densifier, operating temperatures of the equipment, temperature and/or composition of the granules, use of additive ingredients such as liquid binders and flow aids, may be used to optimize densification of the spray dried granules in the process of the present invention. See, for example, the methods in Appel et al., U.S. Patent 5,133,924, issued on July 28, 1992 (spray dried granules are brought into a deformable state prior to compaction); Delwel et al., U.S. Patent 4,637,891, issued January 20, 1987 (granulation of spray dried granules with a liquid binder and aluminosilicate); Kruse et al., U.S. Patent 4,726,908, issued February 23, 1988 (granulation of spray dried granules with a liquid binder and aluminosilicate); and Bortolotti et al., U.S. Patent 5,160,657, issued November 3, 1992 (coating compacted spray dried granules with a liquid binder and aluminosilicate).

Admixture process

Other aspects of the process of the invention specifically include blending additional detergent materials with the various agglomerates, spray dried granules and combinations thereof. This admixing step may be enhanced by combining the agglomerates, granules or combinations thereof with additional detergent materials and a liquid binder in a mixing drum or similar device. Optionally, the additional detergent materials may be coated with a nonionic surfactant or other liquid binder as previously described prior to the admixing step to prevent any adverse interaction with the other detergent ingredients (e.g., anionic surfactants) prior to immersion in the wash solution (i.e., during processing and storage). This coating with a liquid binder or nonionic surfactant also improves the flow properties of the detergent composition in which the builder material is included.

Other procedures

In yet another embodiment of the process, the high density detergent composition can be prepared by introducing a liquid acid precursor of an anionic surfactant, an alkaline inorganic material (e.g. sodium carbonate) and optionally other detergent ingredients into a high speed mixer/densifier (residence time 5-30 seconds) to form agglomerates containing a partially or fully neutralized anionic surfactant salt and the other starting detergent ingredients. The contents in the high speed mixer/densifier can then be passed to a moderate speed mixer/densifier (e.g. Lödige KM) for further agglomeration to yield the final high density detergent composition. In another embodiment of the process, the surfactant paste is premixed or extruded in a mixing or extruding device, such as a twin-screw extruder (e.g. Werner and Pfleiderer, Continua series), to structure the paste for easier agglomeration. In addition, structuring agents such as polymers, sodium hydroxide, sodium chloride, potassium hydroxide or silicates can be used to prepare the paste for loading with higher amounts of surfactant more appropriate. See Aouad et al., U.S. Patent 5,451,354, issued September 19, 1995.

Optionally, high density detergent compositions can be prepared by blending conventional or densified spray dried detergent granules with detergent agglomerates in various ratios (e.g., a 60:40 weight ratio of granules to agglomerates) prepared by one or a combination of the processes discussed herein. Additional auxiliary ingredients such as enzymes, fragrances or brighteners can be atomized or blended with the agglomerates, granules or mixtures thereof prepared by the processes discussed herein.

Another process of the invention involves cooling a molten surfactant paste and forming platelets on a chill roll, followed by milling the platelets to the desired particle size. The cooled platelets can be further dried using a drum dryer.

In order to make the present invention more clearly understood, reference is made to the following examples, which are intended to be illustrative only and are not intended to limit the scope of protection.

Example I

This example illustrates the process of the invention which produces a free-flowing, granular, high density detergent composition. Two feed streams of different detergent starting ingredients are continuously fed into a Lödige CB 30 mixer/densifier at a rate of 2800 kg/h. One stream comprises a liquid binder containing water and PVNO and the other stream contains the dry detergent materials containing an ester modified carboxymethyl cellulose, aluminosilicate and sodium carbonate. The speed of the shaft in the Lödige CB 30 mixer/densifier is about 1400 rpm and the average residence time is about 10 seconds. The contents from the Lödige CB 30 mixer/densifier are continuously fed into a Lödige KM 600 mixer/densifier for further agglomeration during which the average residence time is about 30 seconds. The resulting detergent agglomerates are then introduced into a fluid bed dryer and then into a flotation cooler with average residence times of about 10 minutes and 15 minutes respectively. A coating agent, aluminosilicate, is introduced after the Lödige KM 600 mixer/densifier to control and prevent over-agglomeration. The detergent agglomerates are then screened using a conventional screening device, resulting in a uniform particle size distribution. The composition of the detergent agglomerate mixture leaving the flotation cooler after three process passes is shown in Table I below: Table I

Example II-V

Several detergent compositions prepared in accordance with the invention and specifically for top loading washing machines are illustrated below. The base granules are prepared by a conventional spray drying process in which the starting ingredients are formed into a slurry and passed through a spray drying tower with a countercurrent of hot air (200-300°C) resulting in the formation of porous granules. The mixed agglomerates are formed from two feed streams of different starting detergent ingredients which are continuously fed at a rate of 1400 kg/h into a Shugi high shear granulator (1000-4000 rpm) or a Lödige CB 30 mixer/densifier, one of which contains a liquid binder containing either: 1) PVNO and water, or 2) a copolymer of epichlorohydrin and a cyclic amine group (IME) and water, or 3) the IME material, alkyl ethoxy sulfate surfactant paste and water; and the other stream contains the dry starting detergent ingredients containing a premixed mixture of either: 1) an ester-modified carboxymethyl cellulose, aluminosilicate and sodium carbonate, or 2) an ester-modified carboxymethyl cellulose and aluminosilicate. The speed of the shaft in the Lödige CB 30 mixer/densifier is about 1,400 rpm and the average residence time is about 5-10 seconds. The contents from the Lödige CB 30 mixer/densifier are continuously fed into a Lödige KM 600 mixer/densifier for further agglomeration, during which the average residence time is about 1-2 minutes. The resulting detergent agglomerates are then fed into a fluid bed dryer and into a flotation cooler before being mixed with the spray dried granules. These agglomerates are then mixed with agglomerates made with a surfactant paste containing the surfactant and water and dry detergent ingredients containing a dry detergent material of aluminosilicate and sodium carbonate. The remaining additional detergent ingredients are sprayed onto the mixture of agglomerates and granules or added dry to it.

1: Diethylenetriaminepentaacetic acid.

2: Manufactured according to U.S. Patent 5,415,807, issued May 16, 1995 to Gosselink et al.

3: Nonanoyloxybenzenesulfonate.

4: Purchased from Novo Nordisk A/S.

5: Obtained from Genencor.

6: Purchased from Ciba-Geigy.

7: Copolymer of epichlorohydrin and a cyclic amine group.

8: Alkyl ethoxysulfate.

Claims (10)

1. Process for the continuous production of detergent agglomerates, characterized by the steps: (A) continuously mixing a liquid binder and dry detergent materials in a high speed mixer/densifier to obtain detergent agglomerates, wherein the ratio of liquid binder to dry detergent material is 1:10 to 10:1, wherein the dry detergent materials comprise modified carboxymethyl cellulose; (B) optionally mixing the detergent agglomerates in a moderate speed mixer/densifier to further densify and agglomerate the detergent agglomerates; and (C) Drying the detergent agglomerates to increase their density. 2. A process for producing a high density detergent composition, characterized by the steps: (A) continuously mixing a liquid binder and dry detergent materials in a high speed mixer/densifier to obtain first detergent agglomerates, wherein the ratio of liquid binder to dry detergent material is 1:10 to 10:1, wherein the dry detergent materials comprise modified carboxymethyl cellulose; (B) optionally mixing the first detergent agglomerates in a moderate speed mixer/densifier to increase their density; (C) drying the first detergent agglomerates to further increase their density; (D) continuously mixing a detergent surfactant paste and additional dry detergent materials in a high speed mixer/densifier to obtain second detergent agglomerates, the ratio of the surfactant paste to the additional dry detergent material being 1:10 to 10:1; (E) mixing the second detergent agglomerates in a moderate speed mixer/densifier to increase their density; (F) drying the second detergent agglomerates to further increase their density; and (G) mixing the first detergent agglomerates and the second detergent agglomerates to form the high density detergent composition. 3. The method of any of claims 1-2, wherein the liquid binder is characterized by water, surfactant paste selected from branched and linear anionic, nonionic, zwitterionic, ampholytic and cationic classes and compatible mixtures thereof, and a polymer selected from the group consisting of dye transfer agents, polyamines, homopolymers and copolymers of polyacrylates, homopolymers and copolymers of polyacrylamides, homopolymers and copolymers of polyvinyl alcohol, homopolymers and copolymers of polyvinyl pyrrolidone, polymaleates, aliphatic polyesters, natural proteins, synthetic noncrystalline polyamino acids, water soluble nylons, polyethylene glycol, polyacrylate and mixtures thereof. 4. The method of any of claims 1-3, wherein the liquid binder is characterized by (1) a mixture of surfactant selected from the group consisting of LAS, sodium ethoxysulfate, and mixtures thereof; and (2) a polymer selected from the group consisting of a polyvinyl N-oxide, a copolymer of epichlorohydrin and a cyclic amine group, homopolymers and copolymers of polyacrylates, and mixtures thereof. 5. A process according to any one of claims 1-4, wherein the surfactant paste has a viscosity, measured at 70°C and at shear rates of 10 to 100 s⁻¹, of 50,000 cps to 450,000 cps, and is further characterized by water and additional surfactant selected from the group consisting of nonionic, zwitterionic, ampholytic and cationic surfactants and mixtures thereof. 6. A process for the continuous production of a high density detergent composition, characterized by the steps: (A) spray drying an aqueous slurry containing additional detergent ingredients to form spray dried granules; (B) continuously mixing a liquid binder and dry detergent materials in a high speed mixer/densifier to obtain detergent agglomerates, wherein the ratio of the liquid binder to the dry detergent materials 1:10 to 10:1, wherein the dry detergent materials comprise modified carboxymethyl cellulose; (C) optionally mixing the detergent agglomerates in a moderate speed mixer/densifier to increase their density; (D) drying the detergent agglomerates to further increase their density; and (E) mixing the granules and the detergent agglomerates together to form the high density detergent composition. 7. A process for the continuous production of a high density detergent composition, characterized by the steps: (A) continuously mixing a liquid binder and dry detergent materials in a high speed mixer/densifier to obtain first detergent agglomerates, wherein the ratio of liquid binder to dry detergent material is 1:10 to 10:1, wherein the dry detergent materials comprise modified carboxymethyl cellulose; (B) optionally mixing the first detergent agglomerates in a moderate speed mixer/densifier to increase their density; (C) drying the first detergent agglomerates to further increase their density; (D) continuously mixing an acid precursor of an anionic surfactant and additional dry detergent materials containing an alkaline inorganic material capable of neutralizing the acid precursor in a high speed mixer/densifier to obtain second detergent agglomerates, wherein the ratio of the anionic surfactant to the additional dry detergent materials is 1:10 to 10:1; (E) optionally mixing the second detergent agglomerates in a moderate speed mixer/densifier to increase their density; (F) drying the second detergent agglomerates to increase their density; and mixing the first detergent agglomerates and the second detergent agglomerates to form the high density detergent composition. 8. Process for the continuous production of detergent agglomerates, characterized by the steps: (A) continuously mixing a liquid binder and dry detergent materials in a high speed mixer/densifier to produce de to obtain detergent agglomerates, wherein the ratio of the liquid binder to the dry detergent material is 1:10 to 10:1, wherein the dry detergent materials consist essentially of modified carboxymethyl cellulose; (B) optionally mixing the detergent agglomerates in a moderate speed mixer/densifier to further densify and agglomerate the detergent agglomerates; and (C) Drying the detergent agglomerates to increase their density. 9. The method of any of claims 1-8, wherein the liquid binder is characterized by water, surfactant paste selected from branched and linear anionic, nonionic, zwitterionic, ampholytic and cationic classes and compatible mixtures thereof, and a polymer selected from the group consisting of dye transfer agents, polyamines, homopolymers and copolymers of polyacrylates, homopolymers and copolymers of polyacrylamides, homopolymers and copolymers of polyvinyl alcohol, homopolymers and copolymers of polyvinyl pyrrolidone, polymaleates, aliphatic polyesters, natural proteins, synthetic noncrystalline polyamino acids, water soluble nylons, polyethylene glycol, polyacrylate and mixtures thereof. 10. The method of any of claims 1-9, wherein the liquid binder is characterized by (1) a mixture of surfactant selected from the group consisting of LAS, sodium ethoxysulfate, and mixtures thereof; and (2) a polymer selected from the group consisting of a polyvinyl N-oxide, a copolymer of epichlorohydrin and a cyclic amine group, homopolymers and copolymers of polyacrylates, and mixtures thereof.