DE69715224T2 - METHOD FOR PRODUCING A DETERGENT COMPOSITION BY A NO-TOWER METHOD - Google Patents

Description

Field of the invention

The present invention relates generally to a towerless process for producing a particulate detergent composition. More particularly, the invention relates to a continuous process during which detergent agglomerates are produced by feeding a surfactant and coating materials into a series of mixers. The process produces a free-flowing detergent composition whose density can be adjusted to meet a wide range of consumer needs and which can be sold commercially.

Background of the invention

Recently, there has been a great deal of interest in the detergent industry in laundry detergents that are "compact" and therefore have low dosage volumes. To facilitate the manufacture of these so-called low dosage detergents, numerous attempts have been made to produce detergents with high bulk density, for example with a density of 600 g/l or higher. The low dosage detergents are currently in high demand because they conserve resources and can be sold in small packages that are more convenient for consumers. However, the extent to which modern detergent products need to be "compact" remains intrinsically unclear. In fact, many consumers, particularly in developing countries, continue to prefer higher dosage levels in their respective laundry washing operations.

Generally, there are two primary types of processes by which detergent granules or powders can be made. The first type of process involves spray drying an aqueous detergent slurry in a spray drying tower to produce highly porous detergent granules (e.g., a tower process for low density detergent compositions). In the second type of process, the various detergent components are dry blended and then agglomerated with a binder such as a nonionic or anionic surfactant to produce high density detergent compositions (e.g., agglomeration process for high density detergent compositions). In the above two processes, the important factors that determine the density of the resulting detergent granules are the shape, porosity and particle size distribution of the granules, the density of the various starting materials, the shape of the various starting materials and their respective chemical compositions.

There have been numerous attempts in the art to provide processes that increase the density of detergent granules or powders. Particular attention has been paid to the densification of spray dried granules by post-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®. This device comprises a virtually 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 attempts have been made to provide continuous processes for increasing the density of "post-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. While these processes achieve the desired increase in density by treating or compacting "post-tower" or spray-dried granules, they are limited in their ability to use a higher active surfactant level without a subsequent coating step. In addition, "post-tower" treating or compacting is not favorable in terms of economics (high capital costs) and complexity of operation. Furthermore, all of the aforementioned processes are primarily aimed at compacting or otherwise processing spray dried granules. Currently, the relative amounts and types of materials that have been subjected to spray drying processes in the manufacture of detergent granules are limited. For example, it has been difficult to achieve high levels of surfactant in the resulting detergent composition, a feature that facilitates the manufacture of detergents in a more efficient manner. Therefore, it would be desirable to have a process by which detergent compositions can be manufactured without the limitations imposed by conventional spray drying techniques.

To this end, the art is replete with disclosures of processes involving 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. While such attempts suggest that their process can be used to produce detergent agglomerates, they do not provide a mechanism by which detergent starting materials in the form of pastes, liquids and dry materials can be effectively agglomerated into friable, free-flowing detergent agglomerates.

Accordingly, there remains a need in the art to have an agglomeration (towerless) process for the continuous production of a detergent composition having a high density delivered directly from the starting detergent ingredients, and preferably the density can be achieved by adjusting the process condition. Furthermore, there remains a need for such a process which is more efficient, flexible and economical to facilitate the large-scale production of detergents, (1) because of the flexibility in the ultimate density of the final composition and (2) the flexibility in incorporating several different types of detergent ingredients, particularly detergent ingredients in the form of liquid, into the process.

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., UK Patent No. 1,517,713 (Unilever); and Curtis, European Patent Application 451,894.

The following references relate to the production of detergents by agglomeration: Beujean et al., published no. WO-93/23 523 (Henkel); Lutz et al., U.S. Patent No. 4,992,079 (FMC Corporation); Porasik et al., U.S. Patent No. 4,427,417 (Korex); Beerse et al., U.S. Patent No. 5,108,646 (Procter &Gamble); Capeci et al., U.S. Patent No. 5,366,652 (Procter &Gamble); Hollingsworth et al., European Patent Application 351 937 (Unilever); Swatling et al., U.S. Patent No. 5,205,958; Dhalewadikar et al., published no. WO-96/04359 (Unilever).

For example, published No. WO-93/23 523 (Henkel) describes the process which comprises pre-agglomeration by a low speed mixer and a further agglomeration step by a high speed mixer to obtain a high density detergent composition with less than 25% by weight of granules with a diameter greater than 2 mm. US Patent No. 4,427,417 (Korex) describes a continuous process for agglomeration which reduces cake formation and formation of oversized agglomerates.

US-5,554,587 describes a process for preparing detergent compositions which comprises introducing air into a mixer during the agglomeration of a surfactant paste and other detergent ingredients so that at least a minor amount of water from the surfactant paste is absorbed by the air.

WO-9 609 370 describes a process for producing high density detergent compositions comprising the steps of mixing a surfactant paste and dry detergent ingredients in a mixer to form first agglomerates, conditioning the first agglomerates to obtain second agglomerates having a specific particle size, recycling any agglomerates not having the desired particle size for further agglomeration to obtain second agglomerates having the desired particle size, admixing detergent ingredients to the second agglomerates to form a high density detergent composition.

WO-9 510 595 addresses the problem of continuously producing high density detergents and teaches as a solution to this problem a process for continuously producing detergents which comprises the step of continuously mixing a surfactant, builder and powder ingredients in a mixer.

WO-9 512 659 addresses the problem of producing cleaning agents with low relative humidity at elevated process temperatures and solves this problem by using a preconditioned gas in the process conditions.

US-5,489,392 describes a process for producing high density detergents which comprises the steps of mixing a surfactant paste in a mixer to form agglomerates, sieving the agglomerates to form a first agglomerate mixture, separating the agglomerates according to particle size and either crushing or recycling agglomerates for further agglomeration to obtain a final agglomerate mixture having the desired particle size, admixing detergent ingredients to the final agglomerate mixture to obtain a high density detergent composition.

WO-9 201 036 describes a process for producing surfactant granules which comprises the steps of mixing a water-containing surfactant with a solid to form a granule, drying the granule and recycling the dried granule as part of the solid.

No prior art method offers all the advantages and benefits of the present invention.

Summary of the invention

The present invention meets the foregoing needs in the art by providing a process that produces a high density granular detergent composition. The present invention also meets the foregoing needs in the art by providing a process that produces a granular detergent composition because of the flexibility in the ultimate density of the final composition from the agglomeration (e.g., towerless) process. The process does not currently use conventional spray drying towers, which are limited in producing compositions with high surfactant loadings. Furthermore, the process of the present invention is more efficient, economical, and flexible in terms of the variety of detergent compositions that can be produced in the process. In addition, the process is more environmentally friendly in that it does not use spray drying towers, which typically emit particulate matter and volatile organic compounds into the atmosphere.

As used herein, the term "agglomerates" refers to particles formed by agglomerating raw materials with binders such as surfactants and/or inorganic solutions/organic solvents and polymer solutions. As used herein, the term "granulation" refers to thoroughly fluidizing agglomerates to produce free-flowing granulated agglomerates of spherical shape. As used herein, the term "average residence time" refers to the following definition:

average residence time (h) = mass (kg)/flow rate (kg/h)

All percentages used herein are expressed as "weight percent" unless otherwise specified. All ratios are weight ratios unless otherwise specified. As used herein, "comprising" means that other steps and other ingredients that do not affect the result may be added. This term includes the terms "consisting of" and "consisting essentially of."

In accordance with the invention there is provided a process for preparing a granular detergent composition having a density of at least 600 g/l.

The procedure includes the following steps:

(a) dispersing a surfactant and coating the surfactant with fine powder having a diameter of 0.1 to 500 µm (microns) in a chopper-equipped mixer, wherein the mixing conditions include (i) an average residence time of 0.5 to 15 minutes and (ii) an energy input of 0.15 to 7 kJ/kg, whereby first agglomerates and excess fine powder are formed; and

(a') spraying finely atomized liquid onto the first agglomerates in a mixer, wherein the conditions of the mixer are (i) an average residence time of 0.2 to 5 seconds, (ii) a speed the peaks of 10 to 30 m/s and (iii) an energy input of 0.15 to 5 kJ/kg, wherein excess fine powder formed in the first step (a) is added to the first step (a') and wherein second agglomerates are formed; and

(b) granulating the second agglomerates in a third fluid bed dryer and a fluid bed cooler, the conditions of each of these fluid bed devices including (i) an average residence time of 1 to 10 minutes, (ii) a non-fluidized bed depth of 100 to 300 mm, (iii) a droplet spray size of no more than 50 µm (microns), (iv) a spray height of 175 to 250 mm, (v) a fluidization velocity of 0.2 to 1.4 m/s and (vi) a bed temperature of 12 to 100°C, and wherein a coating agent selected from the group comprising aluminosilicates, silicates, carbonates and mixtures thereof is added to the second step either: directly following the fluid bed dryer or the fluid bed cooler; and/or between the fluid bed dryer and the fluid bed cooler; and/or directly following the fluid bed dryer.

Accordingly, it is an object of the invention to provide a process for continuously producing a detergent composition which has flexibility in the density of the final products by regulating the energy input, residence time condition and tip speed condition in the mixers. It is also an object of the invention to provide a process which is more efficient, flexible and economical to facilitate large-scale production. 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 preferred embodiments and appended claims.

Detailed description of the preferred embodiment

The present invention relates to a process which produces free-flowing granular detergent agglomerates having a density of at least 600 g/l. The process produces granular detergent agglomerates from an aqueous and/or non-aqueous surfactant which is subsequently coated with fine powder having a diameter of 0.1 to 500 µm (microns) to obtain low density granules.

Proceedings First step (i) [Step (a)]

In the first step (i) of the process, one or more of aqueous and/or non-aqueous surfactant(s) in the form of a powder, paste and/or liquid, and fine powder having a diameter of 0.1 to 500 µm (microns), preferably 1 to 100 µm (microns) are fed into a first mixer to form agglomerates. (The definition of the surfactants and the fine powder are described in detail below.) Optionally, an internal recycle stream of powder having a diameter of 0.1 to 300 µm (microns) generated in the fluidized bed devices (e.g., fluidized bed dryers and/or fluidized bed coolers) may be fed into the mixer in addition to the fine powder. The amount of such internal recycle stream of powder may be 0 to 60% by weight of the final product.

Chopping knives, which can be attached to the first mixer, are used to break up unwanted oversized agglomerates. Therefore, the process including the second with chopping knives useful to obtain a reduced amount of oversized agglomerates as final products, and such a process is a preferred embodiment of the present invention.

In another embodiment of the invention, the surfactant for the first step (i) may be initially fed into a mixer or pre-mixer (e.g., a conventional screw extruder or other similar mixer) prior to the above, whereupon the mixed detergent materials are fed into the first mixer for agglomeration as described herein.

Generally speaking, the average residence time of the first mixer is in the range of 0.5 to 15 minutes and the energy per unit mass of the first mixer (energy input) is in the range of 0.15 to 7 kJ/kg, more preferably the average residence time of the first mixer is 3 to 6 minutes and the energy per unit mass of the first mixer (energy input) is in the range of 0.15 to 4 kJ/kg.

The examples of the first mixer can be any type of mixer known to those skilled in the art, as long as the mixer can maintain the above-mentioned condition for the first step. An example can be a Lödige KM mixer manufactured by Lödige (Germany). As a result of the first step (i), the agglomerates (first agglomerates) are subsequently obtained. The first agglomerates are then subjected to either (1) the second step, or (2) the first step (ii), followed by the second step.

First step (ii) [Step (a')]

The result from the first step (i) (i.e. the first agglomerates) are fed to a second mixer. The first agglomerates are fed to a second mixer and thereafter finely atomized liquid is sprayed onto the agglomerates in the second mixer. Excess fine powder formed in the first step (i) is added to the first step (ii). When the excess fine powder is added to the first step (ii), spraying the finely atomized liquid is useful to bind the excess fine powder to the surface of agglomerates. 0-10%, more preferably 2-5% of powder detergent ingredients of the type used in the first step (i) and/or other detergent ingredients may be added to the second mixer.

Generally speaking, the average residence time of the second mixer is in the range of 0.2 to 5 seconds and the speed at the tips of the mixer of the second mixer is in the range of 10 m/s to 30 m/s, the energy per unit mass of the second mixer (energy input) of the second mixer is in the range of 0.15 kJ/kg to 5 kJ/kg, more preferably the average residence time of the second mixer is in the range of 0.2 to 5 seconds and the speed at the tips of the second mixer is in the range of 10 m/s to 30 m/s, the energy per unit mass of the second mixer. (energy input) is in the range of 0.15 kJ/kg to 5 kJ/kg, most preferably the mean residence time of the second mixer is in the range of 0.2 to 5 seconds, the speed at the tips of the second mixer is in the range of 15 m/s to 26 m/s, the energy per unit mass of the second mixer (energy input) is 0.2 kJ/kg to 3 kJ/kg.

The examples of the second mixer may be any type of mixer known in the art, as long as the mixer maintains the above condition for the first step (ii) An example can be a Flexomic model manufactured by Schugi (Netherlands). As a result of the first step (ii), the second agglomerates are subsequently obtained.

Second step [step (b)]

In the second step, the first agglomerates from the first step (i) or the second agglomerates from the first step (ii) are fed into a fluidized bed device, such as a fluidized bed, to enhance granulation for the production of free-flowing high density granules. The second step may be carried out in more than one fluidized bed device (e.g., combining different types of fluidized bed devices, such as a fluidized bed dryer and a fluidized bed cooler). Optionally, 0 to 10%, more preferably 2-5%, of powder detergent ingredients of the type used in the first step and/or other detergent ingredients may be added to the second step. In addition, optionally 0 to 20%, more preferably 2 to 10%, of liquid detergent materials of the type used in the first step (i), the first step (ii) and/or other detergent ingredients may be added to the step to enhance granulation and coating onto the surface of the granules.

Generally speaking, in order to achieve the density of at least 600 g/l, preferably more than 650 g/l, the condition of the fluidized bed device can be as follows:

Average residence time: 1 to 10 minutes

Depth of the non-turbulent layer: 100 to 300 mm

Droplet spray size: not more than 50 um (microns)

Spray height: 175 to 250 mm

Turbulence speed: 0.2 to 1.4 m/s

Layer temperature: 12 to 100ºC,

further preferred:

Average residence time: 2 to 6 minutes

Depth of the non-turbulent layer: 100 to 250 mm

Droplet spray size: less than 50 um (microns)

Spray height: 175 to 200 mm

Turbulence speed: 0.3 to 1.0 m/s

Layer temperature: 12 to 80ºC.

If two different types of fluidized bed devices were used, the total average residence time of the second step may be 2 to 20 minutes, more preferably 2 to 12 minutes.

A coating agent to improve the flowability and/or minimize over-agglomeration of the detergent composition is added at one or more of the following points in the present process: (1) the coating agent can be added directly after the fluid bed cooler or fluid bed dryer; (2) the coating agent can be added between the fluid bed dryer and the fluid bed cooler; and/or (3) the coating agent can be added directly to the fluid bed dryer. The coating agent is selected from the group consisting of aluminosilicates, silicates, carbonates, and mixtures thereof. The coating agent not only enhances the free flowability of the resulting detergent composition, which is desired by consumers, by allowing easy scooping of the detergent during of use, but also serves to control agglomeration by preventing or minimizing over-agglomeration. As those skilled in the art are well aware, over-agglomeration can lead to very undesirable flow properties and aesthetics of the final detergent product.

Detergent raw materials

The total amount of surfactants in products made by the present invention included in the following detergent materials, finely atomized liquid and detergent adjunct ingredients is generally from 5% to 60%, more preferably from 12% to 40%, more preferably from 15 to 35% as percentage ranges. The surfactants included in the above may come from any part of the process of the present invention, e.g. from any of the first step (i), the first step (ii) and/or the second step of the present invention.

Cleaning surfactant (aqueous/non-aqueous)

The amount of surfactant in the present process may be 5% to 60%, more preferably 12% to 40%, more preferably 15 to 35% of the total amount of the final product obtained by the process of the present invention.

The surfactant of the present process used as the above-mentioned detergent raw materials in the first step is in the form of powdery, pasty or liquid raw materials.

The surfactant itself is preferably selected from anionic, nonionic, zwitterionic, ampholytic and cationic classes and compatible mixtures thereof. Detergent surfactants useful herein are described in U.S. Patent 3,664,961, Norris, issued May 23, 1972, and U.S. Patent 3,929,678, Laughlin et al., issued December 30, 1975. Useful cationic surfactants also include those described in U.S. Patent 4,222,905, Cockrell, issued September 16, 1980, and U.S. Patent 4,239,659, Murphy, issued December 16, 1980. Of the surfactants, anionic and nonionic substances are preferred and anionic substances are most preferred.

Non-limiting examples of the preferred anionic surfactants useful in the present invention include the conventional C11-C18 alkylbenzenesulfonates ("LAS"), the C10-C20 primary, branched chain and random alkyl sulfates ("AS"), the C10-C18 secondary (2,3) alkyl sulfates of the formula CH3(CH2)x(CHOSO3-M+)CH3 and CH3(CH2)y(CHOSO3-M+)CH2CH3 wherein x and (y + 1) are integers of at least 7, preferably at least 9, and M is a water-solubilizing cation, especially sodium, unsaturated sulfates such as oleyl sulfate, and the C₁₀-C₁₈-alkylalkoxysulfates (“AExS”; especially EO-1-7-ethoxysulfates).

Useful anionic surfactants also include water-soluble salts of 2-acyloxyalkane-1-sulfonic acids having 2 to 9 carbon atoms in the acyl group and 9 to 23 carbon atoms in the alkane moiety; water-soluble salts of olefin sulfonates having 12 to 24 carbon atoms; and betaalkyloxyalkanesulfonates having 1 to 3 carbon atoms in the alkyl group and 8 to 20 carbon atoms in the alkane moiety.

Optionally, other exemplary surfactants useful in the paste used in the invention include C₁₀-C₁₈ alkyl alkoxycarboxylates (particularly EO-1-5-erhoxycarboxylates), the C₁₀-C₁₈ Glycerol ethers, the C₁₀-C₁₈ alkyl polyglycosides and the corresponding sulfated polyglycosides and C₁₂-C₁₈ alpha-sulfonated fatty acid esters. If desired, the conventional nonionic and amphoteric surfactants such as the C₁₂-C₁₈ alkyl ethoxylates ("AE") including the so-called narrow peak alkyl ethoxylates and the C₆-C₁₂ alkylphenol alkoxylates (particularly ethoxylates and mixed ethoxy/propoxy), C₁₀-C₁₈ amine oxides and the like may also be included in the overall compositions. The C₁₀-C₁₈ N-alkyl polyhydroxy fatty acid amides may also be used. Typical examples include the C12-C18 N-methylglucamides; see WO 9 206 154. Other sugar derived surfactants include the N-alkoxy polyhydroxy fatty acid amides such as C10-C18 N-(3-methoxypropyl)glucamide. The N-propyl to N-hexyl C12-C18 glucamides can be used for low sudsing. Conventional C10-C20 soaps can also be used. If high sudsing is desired, the branched chain C10-C16 soaps can be used. Mixtures of anionic and nonionic surfactants are particularly useful. Other conventional useful surfactants are listed in the standard literature.

Cationic surfactants can also be used as cleaning surfactant herein and suitable quaternary ammonium surfactants are selected from mono-C6-C16, preferably C6-C10 N-alkyl or alkenyl ammonium surfactants wherein remaining N-positions are substituted by methyl, hydroxyethyl or hydroxypropyl groups.

Ampholytic surfactants can also be used as the cleaning surfactant herein, which include aliphatic derivatives of heterocyclic secondary and tertiary amines; zwitterionic surfactants, which include derivatives of aliphatic quaternary ammonium, phosphonium and sulfonium compounds; water-soluble salts of esters of alpha-sulfonated fatty acids; alkyl ether sulfates; water-soluble salts of olefin sulfonates; beta-alkyloxyalkanesulfonates; Betaines of the formula R(R¹)₂N⁺R²COO⁻, wherein R is a C₆-C₁₈ hydrocarbyl group, preferably a C₁₀-C₁₆ alkyl group or a C₁₀-C₁₆ acylamidoalkyl group, each R¹ is typically C₁-C₃ alkyl, preferably methyl and R² is a C₁-C₅ hydrocarbyl group, preferably a C₁-C₃ alkylene group, more preferably a C₁-C₂ alkylene group. Examples of suitable betaines include coconut acyl amidopropyl dimethyl betaine; hexadecyl dimethyl betaine; C12-14 acylamidopropyl betaine; C8-14 acylanidohexyldiethyl betaine;

4[C14-16-acylmethylamidodiethylammonio]-1-carboxybutane; C16-18 acylamidodimethyl betaine; C12-16 acyl amidopentane diethyl betaine; and C12-16 acylmethylamidodimethylbetaine. Preferred betaines are C12 -C18 dimethyl ammoniohexanoate and the C10,2-18 acylamidopropane (or ethane) dimethyl (or diethyl) betaines; and the sultaines of the formula R(R¹)₂N⁺R²SO₃⁻, wherein R is a C₆-C₁₈ hydrocarbyl group, preferably a C₁₀-C₁₆ alkyl group, more preferably a C₁ ;₂-C₁₃-alkyl group, each R¹ is typically C₁-C₃-alkyl, preferably methyl, and R² is a C₁-C₆-hydrocarbyl group, preferably a C₁-C₃-alkylene group or preferably a hydroxyalkylene group is. Examples of suitable sultaines include C₁₂-C₁₄-dimethylammonio-2-hydroxypropylsulfonate, C₁₂-C₁₄-amidopropylammonio-2-hydroxypropylsultaine, C₁₂-C₁₄-dihydroxyethylammoniopropanesulfonate and C₁ ;₆-C₁₈-dimethylammoniohexanesulfonate, with C₁₂-C₁₄-amidopropylammonio-2-hydroxypropylsultaine being preferred.

Fine powder

The amount of fine powder used in the present process used in the first step may be 94% to 30%, preferably 86% to 54% of the total amount of the starting material for the first step. The fine starting powder of the present process is preferably selected from the group consisting of ground anhydrous soda, powdered sodium tripolyphosphate (STPP), hydrated tripolyphosphate, ground sodium sulfates, aluminosilicates, crystalline layered silicates, nitrilotriacetates (NTA), phosphates, precipitated silicates, polymers, carbonates, citrates, powdered surfactants (such as powdered alkanesulfonic acids) and an internal recycle stream of powder coming from the processes of the present invention, wherein the mean diameter of the powder is 0.1 to 500 µm (microns), preferably 1 to 300 µm (microns), more preferably 5 to 100 µm (microns). In the case of using hydrated STPP as a fine powder in the present invention, STPP hydrated to a level of not less than 50% is preferred. 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 wishing to be bound by theory, it is believed that such high calcium ion exchange rate and capacity are a function of several interdependent factors arising from the process by which the aluminosilicate ion exchange material is prepared. In this regard, the aluminosilicate ion exchange materials used herein are preferably prepared in accordance with 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. Furthermore, the aluminosilicate ion exchange material is preferably in an overdried form to facilitate the preparation of friable detergent agglomerates as described herein. The aluminosilicate ion exchange materials used herein preferably have particle size diameters that optimize their effectiveness as detergent builders. The term "particle size diameter" as used herein means the mean particle 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 µm (microns) to 10 µm (microns), more preferably 0.5 µm (microns) to 9 µm (microns). Most preferably, the particle size diameter is about 1 µm (microns) to about 8 µm (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 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 may 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 200 mg equivalent CaCO3 hardness/gram, calculated on an anhydrous basis, and which is preferably in the range of 300 to 352 mg equivalent CaCO3 hardness/gram.

Finely atomized liquid

The amount of the finely atomized liquid of the present process may be 1% to 10% (active basis), preferably 2% to 6% (active basis) of the total amount of the final product obtained by the process of the present invention. The finely atomized liquid of the present process may be selected from the group containing liquid silicate, anionic or cationic surfactants present in liquid form, aqueous or non-aqueous polymer solutions, water and mixtures thereof. Other optional examples of the finely atomized liquid of the present invention may be sodium carboxymethylcellulose solution, polyethylene glycol (PEG) and solutions of dimethylenetriaminepentamethylphosphonic acid (DETMP).

The preferred examples of the anionic surfactant solutions that can be used as the finely atomized liquid in the present inventions are 88-97% active HLAS, 30-50% active NaLAS, 28% active AE3S solution, 40-50% active liquid silicate, etc.

Cationic surfactants may also be used as a finely atomized liquid herein and suitable quaternary ammonium surfactants are selected from mono-C6-C16, preferably C6-C10 N-alkyl or alkenyl ammonium surfactants wherein residual N-positions are substituted by methyl, hydroxyethyl or hydroxypropyl groups.

Preferred examples of the aqueous or non-aqueous polymer solutions that can be used as the finely atomized liquid in the present inventions are modified polyamines comprising a polyamine backbone corresponding to the formula:

with a modified polyamine formula V(n+1)WmY'nZ or a polyamine backbone according to the formula:

with a modified polyamine formula V(n-k+1)WmYnYkZ, where k is less than or equal to n, wherein the polyamine backbone prior to modification has a molecular weight of greater than about 200 Daltons, where

i) V units are terminal units of the following formula:

ii) W units are backbone units of the following formula:

iii) Y units are branched units of the following formula:

(iv) Z units are terminal units of the following formula:

wherein backbone linker R units are selected from the group consisting of C₂-C₁₂alkylene, C₄-C₁₂alkenylene, C₃-C₁₂hydroxyalkylene, C₄-C₁₂dihydroxyalkylene, C₈-C₁₂dialkylarylene, -(R¹O)xR¹-, -(R¹O)xR⁵(OR¹)x, -(CH₂CH(OR²)CH₂O)z(R¹O)yR¹(OCH₂CH(OR²)CH₂)w-, -C(O)(R⁴)rC(O)-, -CH2CH(OR2)CH2- and mixtures thereof; wherein R1 is C2-C6 alkylene and mixtures thereof; R2 is hydrogen, -(R1O)xB and mixtures thereof; R3 is C1-C18 alkyl, C7-C12 arylalkyl, C7-C12 alkyl-substituted aryl, C6-C12 aryl and mixtures thereof; R4 is C₁-C₁₂alkylene, C₄-C₁₂alkenylene, C₈-C₁₂arylalkylene, C₆-C₁₀ arylene and mixtures thereof or R⁵ C₁-C₁₂alkylene, C₃-C₁₂hydroxyalkylene, C₄-C₁₂dihydroxyalkylene, C₈-C₁₂dialkylarylene, -C(O)-, -C(O)NHR⁶NHC(O)-, -R¹(OR¹)-, -C(O)(R⁴)rC(O)-, -CH₂CH(OH)CH₂-, -CH₂CH(OH)CH₂O(R¹O)y-R¹OCH₂CH(OH)CH₂- and mixtures thereof; R⁶ is C₂-C₁₂ alkylene or C₆-C₁₂ arylene; E units are selected from the group consisting of hydrogen, C₁-C₂₂ alkyl, C₃-C₂₂ alkenyl, C₇-C₂₂ arylalkyl, C₂-C₂₂ hydroxyalkyl, -(CH₂)pCO₂M, -(CH₂)qSO₃M, - CH(CH₂CO₂M)CO₂M, -(CH₂)pPO₃M, -(R¹O)xB, -C(O)R³ and mixtures thereof; oxide; B is hydrogen, C1-C6 alkyl, -(CH2)qSO3M, -(CH2)pCO2M, -(CH2)q(CHSO3M)CH2SO3M, -(CH2)q-(CHSO2M)CH2SO3M, -(CH2)q-(CHSO2M)CH2SO3M, -(CH2)pPO3M, -PO3M and mixtures thereof; M is hydrogen or a water-soluble cation in sufficient amount to satisfy charge equilibrium; X is a water-soluble anion; m has a value of 4 to 400; n has a value of 0 to 200; p has a value of 1 to 6; q has a value of 0 to 6; r has a value of 0 or 1; w has a value of 0 or 1; x has a value of 1 to 100; y has a value of 0 to 100; z has a value of 0 or 1. An example of the most preferred polyethyleneimines would be a polyethyleneimine having a molecular weight of 1800 which is further ethoxylated to a degree of about 7 ethyleneoxy residues per nitrogen (PEI 1800, E7). The above polymer solution is preferably a pre-complex with anionic surfactant such as NaLAS.

Other preferred examples of the aqueous or non-aqueous polymer solutions that can be used as the finely atomized liquid in the present invention are polymeric polycarboxylate dispersants that can be prepared by polymerizing or copolymerizing suitable unsaturated monomers, preferably in their acid form. Unsaturated monomeric acids that can be polymerized to form suitable polymeric polycarboxylates include acrylic acid, maleic acid (or maleic anhydride), fumaric acid, itaconic acid, aconitic acid, mesaconic acid, citraconic acid, and methylenemalonic acid. The presence in the polymeric polycarboxylates herein of monomeric segments that do not contain carboxylate radicals such as vinyl methyl ether, styrene, ethylene, etc. is suitable, provided that such segments do not constitute more than 40% by weight of the polymer.

Homopolymeric polycarboxylates having molecular weights of over 4000, as described next, are preferred. Particularly suitable homopolymeric polycarboxylates may be derived from acrylic acid. Such acrylic acid-based polymers useful herein are the water-soluble salts of polymerized acrylic acid. The average molecular weight of such polymers in acid form preferably ranges from over 4000 to 10,000, preferably from over 4000 to 7000, and most preferably from over 4000 to 5000. Water-soluble salts of such acrylic acid polymers may include, for example, the alkali metal, ammonium, and substituted ammonium salts.

Copolymeric polycarboxylates, such as acrylic acid/maleic acid based copolymers, may also be used. Such materials include the water-soluble salts of copolymers of acrylic acid and maleic acid. The average molecular weight of such copolymers in acid form ranges preferably from 2,000 to 100,000, more preferably from 5,000 to 75,000, most preferably from 7,000 to 65,000. The ratio of acrylate to maleate segments in such copolymers generally ranges from 30:1 to 1:1, more preferably from 10:1 to 2:1. Water-soluble salts of such acrylic acid/maleic acid copolymers may include, for example, the alkali metal, ammonium and substituted ammonium salts. It is preferred that the above polymer solution forms a pre-complex with anionic surfactant such as LAS.

Cleaning agent additives

The detergent starting material in the present process may include additional detergent ingredients and/or any number of additional ingredients may be introduced into the detergent composition during subsequent steps of the present process. These additional ingredients include other detergent builders, bleaches, bleach activators, foam boosters or foam suppressors, antitarnish and anticorrosive agents, soil suspending agents, soil repellents, germicides, pH adjusters, non-builder alkalinity sources, chelating agents, smectic clays, enzymes, enzyme stabilizers and perfumes; see U.S. Patent 3,936,537, issued February 3, 1976 to Baskerville, Jr. et al.

Other builders can generally be selected from the various water-soluble alkali metal, ammonium or substituted ammonium phosphates, polyphosphates, phosphonates, polyphosphonates, carbonates, borates, polyhydroxysulfonates, polyacetates, carboxylates and polycarboxylates. The alkali metal, especially sodium salts of the above are preferred. Preferred phosphates for use herein are the phosphates, carbonates, C₁₀₋₁₈ fatty acids, polycarboxylates, and mixtures thereof. More preferred are sodium tripolyphosphate, tetrasodium pyrophosphate, citrate, tartrate mono- and disuccinates, and mixtures thereof (see below).

Compared to amorphous sodium silicates, crystalline sodium layered silicates exhibit clearly improved calcium and magnesium ion exchange capacity. In addition, the sodium layered silicates prefer magnesium ions over calcium ions, a feature required to ensure that virtually all of the "hardness" is removed from the wash water. However, these crystalline sodium layered silicates are generally more expensive than amorphous silicates and other builders. Consequently, in order to provide an economically viable laundry detergent, the proportion of crystalline sodium layered silicates used must be carefully determined. Such crystalline sodium layered silicates are discussed in Corkill et al., U.S. Patent No. 4,605,509.

Specific examples of inorganic phosphate builders are sodium and potassium tripolyphosphate, pyrophosphate, polymeric metaphosphate having a degree of polymerization of 6 to 21, and orthophosphates. Examples of polyphosphonate builders are the sodium and potassium salts of ethylene diphosphonic acid, the sodium and potassium salts of ethane-1-hydroxy-1,1-diphosphonic acid, and the sodium and potassium salts of ethane-1,1,2-triphosphonic acid. Other phosphorus builder compounds are described in U.S. Patents 3,159,581; 3,213,030; 3,422,021; 3,422,137; 3,400,176, and 3,400,148.

Examples of inorganic non-phosphorus builders are tetraborate decahydrate and silicates having a weight ratio of SiO2 to alkali metal oxide of 0.5 to 4.0, preferably 1.0 to 2.4. Water-soluble organic non-phosphorus builders useful herein include the various alkali metal, ammonium and substituted ammonium polyacetates, carboxylates, polycarboxylates and polyhydroxysulfonates. Examples of polyacetate and polycarboxylate builders are the sodium, potassium, lithium, ammonium and substituted ammonium salts of ethylenediaminetetraacetic acid, nitrilotriacetic acid, oxydisuccinic acid, mellitic acid, benzenepolycarboxylic acids and citric acid.

Polymeric polycarboxylate builders are shown in U.S. Patent 3,308,067, Diehl, issued March 7, 1967. Such materials include the water-soluble salts of homo- and copolymers of aliphatic carboxylic acids such as maleic acid, itaconic acid, mesaconic acid, fumaric acid, aconitic acid, citraconic acid and methylenemalonic acid. Some of these materials are useful as a water-soluble anionic polymer, as described below, but only in intimate admixture with the non-soap anionic surfactant.

Other suitable polycarboxylates for use herein are the polyacetal carboxylates as described in U.S. Patent 4,144,226, issued March 13, 1979 to Crutchfield et al. and U.S. Patent 4,246,495, issued March 27, 1979 to Crutchfield et al. These polyacetal carboxylates can be prepared by contacting under polymerization conditions an ester of glyoxylic acid and a polymerization initiator. 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 the ether carboxylate builder compositions which comprise a combination of tartrate monosuccinate and Tartrate disuccinate as described in U.S. Patent 4,663,071, Bush et al., issued May 5, 1987.

Bleaching agents and activators are described in U.S. Patent 4,412,934, Chung et al., issued November 1, 1983, and in U.S. Patent 4,483,781, Hartman, issued November 20, 1984. Sequestering agents are also described in U.S. Patent 4,663,071, Bush et al., column 17, line 54 through column 18, line 68. Suds modifiers are also optional ingredients and are described in U.S. Patents 3,933,672, issued January 20, 1976, to Bartoletta et al., and 4,136,045, issued January 23, 1979, to Gault et al.

Suitable smectic clays for use herein are described in U.S. Patent 4,762,645, Tucker et al., issued August 9, 1988, column 6, line 3 through column 7, line 24. Suitable additional detergent builders for use herein are listed in the Baskerville patent, column 13, line 54 through column 16, line 16, and in U.S. Patent 4,663,071, Bush et al., issued May 5, 1987.

Optional procedural steps

Optionally, the method may include the step of spraying an additional binder into one or more of the first, second and/or third mixers for the present invention. A binder is added for the purposes of improving agglomeration by providing a "binding" or "sticking" agent for the detergent components. The binder is preferably selected from the group consisting of water, anionic surfactants, nonionic surfactants, liquid silicates, 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.).

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

Another optional step of the present process involves finishing the resulting detergent agglomerates by a variety of methods, including spraying and/or admixing other conventional detergent ingredients. For example, the finishing step involves spraying perfumes, brighteners and enzymes onto the finished agglomerates to provide a more complete detergent composition. Such techniques and ingredients are well known in the art.

Another optional step in the process involves surfactant paste structuring processes, e.g., curing an aqueous anionic surfactant paste by introducing a paste curing material using an extruder prior to the process of the present invention.

In order to make the present invention more easily understood, reference is made to the following examples, which are intended to be merely illustrative and not limitative of the scope.

Examples Example 1:

The following is an example of obtaining high density agglomerates using a Lödige KM mixer (KM-600), followed by a Schugi FX-160 mixer, further followed by a fluidized bed device.

[Step 1] 120-260 kg/hr of HLAS (an acid precursor of C11-C18 alkylbenzene sulfonate; 95% active) at about 45-60ºC, are dispersed by chopper blades and/or the plates of a KM-600 mixer together with 220 kg/hr of powdered STPP (average particle size 40-75 µm (microns)), 160-200 kg/hr of ground anhydrous soda (average particle size 15 µm (microns)), 80-120 kg/hr of ground sodium sulfate (average particle size 15 µm (microns)) and 200 kg/hr of an internal recycle stream of powder. Serrated plates can be used as mixing elements in the KM mixer. Chopping knives for the KM mixer can be used to reduce the amount of oversized agglomerates. The condition for the KM mixer is as follows:

Average dwell time: 3-6 minutes

Energy input: 0.15-2 kJ/kg

Mixer speed: 100-150 rpm

Jacket temperature: 30-50ºC.

[Step 2] The agglomerates from the KM-600 mixer are fed into the Schugi FX-160 mixer. 10-20 kg/h of HLAS (an acid precursor of C₁₁-C₁₈ alkylbenzene sulfonate; 94-97% active) are dispersed as a finely atomized liquid in the Schugi mixer at 50 to 60ºC. 20-80 kg/h of anhydrous soda (average particle size of 10-20 µm (microns)) are added into the Schugi mixer. The condition for the Schugi mixer is as follows:

Average dwell time: 0.2-5 seconds

Speed at the tips: 16-26 m/s

Energy input: 0.15-2 kJ/kg

Mixer speed: 2000-3200 rpm.

[Step 3] The agglomerates from the Schugi mixer are fed into a fluid bed dryer for drying, rounding and growing agglomerates. 20-80 kg/h of liquid silicate (43% solids, 2.0 R) can also be added in the fluid bed dryer at 35 W. The condition of the fluid bed dryer is as follows:

Average residence time: 4 to 8 minutes

Depth of the non-turbulent layer: 200 mm

Droplet spray size: less than 50 um (microns)

Spray height: 175 to 250 mm (above the distributor plate)

Turbulence speed: 0.4-0.8 m/s

Layer temperature: 40 to 70ºC

The result from step 3 has a density of 700 g/l and can be subjected to the optional process of cooling, classification and/or crushing or grinding.

Example 2

The following is an example of obtaining high density agglomerates using a Lödige KM mixer (KM-600), followed by a Schugi FX-160 mixer, then a fluidized bed device.

[Step 1] 15 kg/h-30 kg/h of HLAS (an acid precursor of C11-C18 alkylbenzene sulfonate; 95% active) at 45-60ºC is dispersed by the chopper blades and/or the plates of a KM-600 mixer along with 220 kg/h of a powdered STPP (average particle size 40-75 µm (microns)), 160-200 kg/h of ground anhydrous soda (average particle size 15 µm (microns)), 80-120 kg/h of ground sodium sulfate (average particle size 15 µm (microns)) and 200 kg/h of an internal recycle stream of powder. Serrated plates can be used as mixing elements in the KM mixer. Chopping knives for the KM mixer can be used to reduce the amount of oversized agglomerates. The condition for the KM mixer is as follows:

Average dwell time: 3-6 minutes

Energy input: 0.15-2 kJ/kg

Mixer speed: 100-150 rpm

Jacket temperature: 30-50ºC.

[Step 2] The agglomerates from the KM-600 mixer are fed into the Schugi FX-160 mixer. 10-25 kg/h of neutralized AE3S liquid (25-28% active) are dispersed as a finely atomized liquid in the Schugi mixer at 30-40ºC. 20-80 kg/h of anhydrous soda is added into the Schugi mixer. The condition for the Schugi mixer is as follows:

Average dwell time: 0.2-5 seconds

Speed at the tips: 16-26 m/s

Energy input: 0.15-2 kJ/kg

Mixer speed: 2000-3200 rpm.

[Step 3] The agglomerates from the Schugi mixer are fed into a fluid bed dryer for drying, rounding and growing agglomerates. 20-80 kg/h of liquid silicate (43% solids, 2.0 R) can also be added in the fluid bed dryer at 35ºC. The condition of the fluid bed dryer is as follows:

Average dwell time: 2-4 minutes

Depth of the non-turbulent layer: 200 mm

Droplet spray size: less than 50 um (microns)

Spray height: 175 to 250 mm (above the distributor plate)

Turbulence speed: 0.4-0.8 m/s

Layer temperature: 40 to 70ºC

The result from step 3 has a density of 700 g/l and can be subjected to the optional process of cooling, classification and/or crushing or grinding.

Example 3

The following is an example of obtaining high density agglomerates using a Lödige KM mixer (KM-600) followed by a fluidized bed device for further agglomerations.

[Step 1] 250-270 kg/hr of aqueous coconut fatty alcohol sulfate surfactant paste (C12-C18, 71.5% active), 40-80 kg/hr of HLAS (an acid precursor of C11-C18 alkylbenzene sulfonate; 94-97% active) are fed into a KM-600 mixer along with 220 kg/hr of powdered STPP (average particle size 40-75 µm (microns)), 160-200 kg/hr of ground anhydrous soda ash (average particle size 15 µm (microns)) and 200 kg/hr of an internal recycle stream of powders. The surfactant paste is fed at 40 to 52ºC and the powders are fed at room temperature. Chipping knives for the KM mixer can be used to reduce the amount of oversized agglomerates. The condition for the KM mixer is as follows:

Average dwell time: 3-6 minutes

Energy input: 0.15-2 kJ/kg

Mixer speed: 100-150 rpm

Jacket temperature: 30-50ºC.

[Step 2] The agglomerates from the KM mixer are fed into a fluid bed dryer for drying, rounding and growing agglomerates. 20-80 kg/h of liquid silicate (43% solids, 2.0 R) can also be added in the fluid bed dryer at 35ºC. The condition of the fluid bed dryer is as follows:

Average dwell time: 2-4 minutes

Depth of the non-turbulent layer: 200 mm

Droplet spray size: less than 50 um (microns)

Spray height: 175 to 250 mm (above the distributor plate)

Turbulence speed: 0.4-0.8 m/s

Layer temperature: 40 to 70ºC

The result of step 3 has a density of at least 700 g/l and can be subjected to the optional process of cooling, classification and/or crushing or grinding.

Having thus described the invention in detail, it will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention, and the invention is not intended to be limited to the embodiments set forth in the specification.

Claims (7)

1. A towerless process for producing a granular detergent composition having a density of at least 600 g/l, comprising the steps of: (a) dispersing a surfactant and coating the surfactant with fine powder, having a particle diameter of 0.1 to 500 µm (microns), in a mixer equipped with chopper blades, wherein the mixer conditions include (i) an average residence time of 0.5 to 15 minutes and (ii) an energy input of 0.15 to 7 kJ/kg, whereby first agglomerates and excess fine powder are formed; (a') spraying finely atomized liquid onto the first agglomerates in a mixer, wherein the conditions of the mixer include (i) an average residence time of 0.2 to 5 seconds, (ii) a tip velocity of 10 to 30 m/s, and (iii) an energy input of 0.15 to 5 kJ/kg, whereby excess fine powder formed in the first step (a) is added to the first step (a') and second agglomerates are formed; and (b) granulating the second agglomerates in a fluid bed dryer and a fluid bed cooler, the conditions of each of these fluid bed devices including (i) an average residence time of 1 to 10 minutes, (ii) a depth of the non-fluidized bed of 100 to 300 mm, (iii) a droplet spray size of not more than 50 µm (microns), (iv) a spray height of 175 to 250 mm, (v) a fluid velocity of 0.2 to 1.4 m/s and (vi) a bed temperature of 12 to 100°C, and wherein a coating agent selected from the group comprising aluminosilicates, silicates, carbonates and mixtures thereof is added to the second step either: immediately following the fluid bed dryer or the fluid bed cooler; and/or between the fluid bed dryer and the fluid bed cooler; and/or immediately following the fluid bed dryer. 2. The method of claim 1, wherein the surfactant is selected from the group consisting of anionic surfactants, nonionic surfactants, cationic surfactants, zwitterionic, ampholytic and mixtures thereof. 3. The method of claim 1, wherein the surfactant is selected from the group consisting of alkylbenzenesulfonates, alkylalkoxysulfates, alkylethoxylates, alkyl sulfates, coconut fatty alcohol sulfates, and mixtures thereof. 4. The process of claim 1, wherein an aqueous or non-aqueous polymer solution is dispersed with the surfactant in step (a). 5. The method of claim 1, wherein the fine powder is selected from the group consisting of anhydrous soda, powdered sodium tripolyphosphate, hydrated tripolyphosphate, sodium sulfates, aluminosilicates, crystalline layered silicates, phosphates, precipitated silicates, polymers, carbonates, citrates, nitrilotriacetates, powdered surfactants and mixtures thereof. 6. The process of claim 1, wherein an internal recycle stream of powder from the fluidized bed device is additionally fed to step (a). 7. The method of claim 1, wherein the finely atomized liquid is selected from the group consisting of liquid silicates, anionic surfactants, cationic surfactants, aqueous polymer solutions, non-aqueous polymer solutions, water, and mixtures thereof.