EP0929648B1

EP0929648B1 - Process for making a detergent composition by non-tower process

Info

Publication number: EP0929648B1
Application number: EP97928871A
Authority: EP
Inventors: Angela Gloria Del Greco; Wayne Edward Beimesch
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1996-10-04
Filing date: 1997-06-05
Publication date: 2002-09-04
Anticipated expiration: 2017-06-05
Also published as: ATE255159T1; EP0929648A1; DE69715224D1; JP2000503715A; CA2268055C; WO1998014558A1; AU7388196A; ATE246726T1; AU3478597A; CA2268062C; JP2000503719A; CN1239992A; AU3378597A; JP2000503716A; JP3299981B2; JP3299985B2; CA2268055A1; JP3305327B2; EP0929650B1; ATE223476T1

Description

FIELD OF THE INVENTION

The present invention generally relates to a non-tower process for producing a particulate detergent composition. More particularly, the invention is directed 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 for wide range of consumer needs, and which can be commercially sold.

BACKGROUND OF THE INVENTION

Recently, there has been considerable interest within the detergent industry for laundry detergents which are "compact" and therefore, have low dosage volumes. To facilitate production of these so-called low dosage detergents, many attempts have been made to produce high bulk density detergents, for example with a density of 600 g/l or higher. The low dosage detergents are currently in high demand as they conserve resources and can be sold in small packages which are more convenient for consumers. However, the extent to which modern detergent products need to be "compact" in nature remains unsettled. In fact, many consumers, especially in developing countries, continue to prefer a higher dosage levels in their respective laundering operations.
Generally, there are two primary types of processes by which detergent granules or powders can be prepared. 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., tower process for low density detergent compositions). In the second type of process, the various detergent components are dry mixed after which they are 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 which govern the density of the resulting detergent granules are the shape, porosity and particle size distribution of said granules, the density of the various starting materials, the shape of the various starting materials, and their respective chemical composition.
There have been many attempts in the art for providing processes which increase the density of detergent granules or powders. Particular attention has been given to 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 apparatus comprises a substantially horizontal, roughened, rotatable table positioned within and at the base of a substantially vertical, smooth walled cylinder. This process, however, is essentially a batch process and is therefore less suitable for the large scale production of detergent powders. More 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 apparatus which pulverizes or grinds the granules and a second apparatus which increases the density of the pulverized granules by agglomeration. While these processes achieve the desired increase in density by treating or densifying "post tower" or spray dried granules, they are limited in their ability to go higher in surfactant active level without subsequent coating step. In addition, treating or densifying by "post tower" is not favourable in terms of economics (high capital cost) and complexity of operation. Moreover, all of the aforementioned processes are directed primarily for densifying or otherwise processing spray dried granules. Currently, the relative amounts and types of materials subjected to spray drying processes in the production of detergent granules has been limited. For example, it has been difficult to attain high levels of surfactant in the resulting detergent composition, a feature which facilitates production of detergents in a more efficient manner. Thus, it would be desirable to have a process by which detergent compositions can be produced without having the limitations imposed by conventional spray drying techniques.
To that end, the art is also replete with disclosures of processes which entail agglomerating 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 starting detergent materials in the form of pastes, liquids and dry materials can be effectively agglomerated into crisp, free flowing detergent agglomerates.
Accordingly, there remains a need in the art to have an agglomeration (non-tower) process for continuously producing a detergent composition having high density delivered directly from starting detergent ingredients, and preferably the density can be achieved by adjusting the process condition. Also, there remains a need for such a process which is more efficient, flexible and economical to facilitate large-scale production of detergents (1) for flexibility in the ultimate density of the final composition, and (2) for flexibility in terms of incorporating several different kinds of detergent ingredients, especially detergent ingredients in the form of liquid, into the process.
The following references are directed to densifying spray-dried granules: Appel et al, U.S. Patent No. 5,133,924 (Lever); Bortolotti et al, U.S. 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 are directed to producing detergents by agglomeration: Beujean et al, Laid-open No.WO93/23,523 (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, Laid Open No.WO96/04359 (Unilever).
For example, the Laid-open No.WO93/23,523 (Henkel) describes the process comprising pre-agglomeration by a low speed mixer and further agglomeration step by high speed mixer for obtaining high density detergent composition with less than 25 wt% of the granules having a diameter over 2 mm. The U.S. Patent No. 4.427,417 (Korex) describes continuous process for agglomeration which reduces caking and oversized agglomerates.
US5554587 discloses a process for preparing detergent compositions comprising inputting 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 said surfactant paste is absorbed by said air.
WO9609370 discloses a process for preparing high density detergent compositions comprising the steps of mixing a surfactant paste and dry detergent ingredients in a mixer to form first agglomerates, conditioning said 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 said second agglomerates to form a high density detergent composition.
WO9510595 addresses the problem of continuously producing high density detergents and teaches as a solution to this problem a process for continuously producing detergents comprising the step of continuously mixing a surfactant, builder and powder ingredients in a mixer.
WO9512659 addresses the problem of preparing low relative humidity detergents in elevated process temperatures and solves this problem by employing a pre-conditioned gas in the process conditions.
US5489392 discloses a process for preparing high density detergents comprising the steps of mixing a surfactant paste in a mixer to form agglomerates, screening said agglomerates to form a first agglomerate mixture, separating the agglomerates according to particle size and either grinding 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.
WO9201036 discloses a process for producing surfactant granules comprising the steps of mixing a water-containing surfactant with a solid to form granules, drying the granules and recycling the dried granules as a portion of the solid.
None of the existing art provides all of the advantages and benefits of the present invention.

SUMMARY OF THE INVENTION

The present invention meets the aforementioned needs in the art by providing a process which produces a high density granular detergent composition. The present invention also meets the aforementioned needs in the art by providing a process which produces a granular detergent composition for flexibility in the ultimate density of the final composition from agglomeration (e.g., non-tower) process. The process does not use the conventional spray drying towers currently which is limited in producing high surfactant loading compositions. In addition, the process of the present invention is more efficient, economical and flexible with regard to the variety of detergent compositions which can be produced in the process. Moreover, the process is more amenable to environmental concerns in that it does not use spray drying towers which typically emit particulates and volatile organic compounds into the atmosphere.
As used herein, the term "agglomerates" refers to particles formed by agglomerating raw materials with binder such as surfactants and or inorganic solutions / organic solvents and polymer solutions. As used herein, the term "granulating" refers to fluidizing agglomerates thoroughly for producing free flowing, round shape granulated-agglomerates. As used herein, the term "mean residence time" refers to following definition: mean residence time (hr) = mass (kg) / flow throughput (kg/hr)
All percentages used herein are expressed as "percent-by-weight" unless indicated otherwise. All ratios are weight ratios unless indicated otherwise. As used herein, "comprising" means that other steps and other ingredients which do not affect the result can be added. This term encompasses the terms "consisting of" and "consisting essentially of".
In accordance with the invention, a process for preparing a granular detergent composition having a density at least 600 g/l is provided.
The process comprises the steps of:
(a) dispersing a surfactant, and coating the surfactant with fine powder having a diameter from 0.1 to 500 µm (microns), in a mixer with choppers attached wherein conditions of the mixer include (i) from 0.5 to 15 minutes of mean residence time and (ii) from 0.15 to 7 kj/kg of energy condition, wherein agglomerates and excessive fine powder are formed; and
(a') spraying finely atomized liquid onto the first agglomerates in a mixer wherein conditions of the mixer include (i) from 0.2 to 5 seconds of mean residence time, (ii) from 10 to 30 m/s of tip speed, and (iii) from 0.15 to 5 kj/kg of energy condition wherein excessive 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 bed dryer and a fluid bed cooler wherein conditions of each of the fluidizing apparatus include (i) from 1 to 10 minutes of mean residence time, (ii) from 100 to 300 mm of depth of unfluidized bed, (iii) not more than 50 micrometer (micron) of droplet spray size, (iv) from 175 to 250 mm of spray height, (v) from 0.2 to 1.4 m/s of fluidizing velocity and (vi) from 12 to 100 °C of bed temperature and wherein a coating agent selected from the group consisting of aluminosilicates, silicates, carbonates and mixtures thereof is added to the second step either : directly after the fluid bed dryer or fluid bed cooler and/or between the fluid bed dryer and fluid bed cooler; and/or directly to 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 with respect to density of the final products by controlling 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 attendant 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 embodiment and the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is directed 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 then coated with fine powder having a diameter from 0.1 to 500 micrometer (microns), in order to obtain low density granules.

Process

First Step (i) [Step(a)]

In the first step (i) of the process, one or more of aqueous and/or non-aqueous surfactant(s) which is/are in the form of powder, paste and/or liquid, and fine powder having, a diameter from 0.1 to 500 micrometer (microns), preferably from 1 to 100 micrometers (microns) are fed into a first mixer, so as to make agglomerates. (The definition of the surfactants and the fine powder are described in detail hereinafter.) Optionally, an internal recycle stream of powder having a diameter of 0.1 to 300 micrometer (microns) generated in the fluidizing apparatus (e.g., fluid bed dryer and/or fluid bed cooler) can be fed into the mixer in addition to the fine powder. The amount of such internal recycle stream of powder can be 0 to 60 wt% of final product.
Choppers which are attachable for the first mixer are used to break up undesirable oversized agglomerates. Therefore, the process including the second with choppers is useful in order to obtain reduced amount of oversized agglomerates as final products, and such process is one preferred embodiment of the present invention.
In another embodiment of the invention, the surfactant for the first step (i) can be initially fed into a mixer or pre-mixer (e.g. a conventional screw extruder or other similar mixer) prior to the above, after which the mixed detergent materials are fed into the first mixer as described herein for agglomeration.
Generally speaking, preferably, the mean residence time of the first mixer is in range from 0.5 to 15 minutes and the energy per unit mass of the first mixer (energy condition) is in range from 0.15 to 7 kj/kg, more preferably, the mean residence time of the first mixer is from 3 to 6 minutes and the energy per unit mass of the first mixer (energy condition) is in range from 0.15 to 4kj/kg.
The examples of the first mixer can be any types of mixer known to the skilled in the art, as long as the mixer can maintain the above mentioned condition for the first step. An Example can be Lödige KM Mixer manufactured by the Lödige company (Germany). As the result of the first step (i), the agglomerates (first agglomerates) are then 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 resultant from the first step (i) (i.e., the first agglomerates) is fed into a second mixer. The first agglomerates are fed into a second mixer, and then finely atomized liquid is sprayed on the agglomerates in the second mixer. Excessive fine powder formed in the first step (i) is added to the first step (ii). If the excessive fine powder is added to the first step (ii), spraying the finely atomized liquid is useful in order to bind the excessive fine powder onto the surface of agglomerates. 0-10%, more preferably 2-5% of powder detergent ingredients of the kind used in the first step (i) andlor other detergent ingredients can be added to the second mixer.
Generally speaking, preferably, the mean residence time of the second mixer is in range from 0.2 to 5 seconds and tip speed of the mixer of the second mixer is in range from 10 m/s to 30 m/s, the energy per unit mass of the second mixer (energy condition) of the second mixer is in range from 0.15 kj/kg to 5 kj/kg, more preferably, the mean residence time of the second mixer is in range from 0.2 to 5 seconds and tip speed of the second mixer is in range from 10 m/s to 30 m/s, the energy per unit mass of the second mixer (energy condition) is in range from 0.15 kj/kg to 5 kj/kg, the most preferably, the mean residence time of the second mixer is in range from 0.2 to 5 seconds, tip speed of the second mixer is in range from 15 m/s to 26 m/s, the energy per unit mass of the second mixer (energy condition) is from 0.2 kj/kg to 3 kj/kg.
The examples of the second mixer can be any types of mixer known to the skilled in the art, as long as the mixer can maintain the above mentioned condition for the first step (ii). An Example can be Flexomic Model manufactured by the Schugi company (Netherlands). As the result of the first step (ii), the second agglomerates are then 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 apparatus, such as fluidized bed, in order to enhance granulation for producing free flowing high density granules. The second step can proceed in more than one fluidized apparatus (e.g., combining different kinds of fluidized apparatus such as fluid bed dryer and fluid bed cooler). Optionally, 0 to 10%, more preferably 2-5% of powder detergent materials of the kind used in the first step and/or other detergent ingredients can be added to the second step. Also, optionally, 0 to 20%, more preferably 2 to 10% of liquid detergent materials of the kind used in the first step (i), the first step (ii) and/or other detergent ingredients can be added to the step, for enhancing granulation and coating on the surface of the granules.
Generally speaking, to achieve the density of at least 600 g/l, preferably more than 650g/l, condition of a fluidized apparatus can be;
Mean residence time : from 1 to 10 minutes
Depth of unfluidized bed : from 100 to 300 mm
Droplet spray size : not more than 50 micrometer (micron)
Spray height: from 175 to 250 mm
Fluidizing velocity : from 0.2 to 1.4 m/s
Bed temperature : from 12 to 100 °C,
more preferably;
Mean residence time : from 2 to 6 minutes
Depth of unfluidized bed : from 100 to 250 mm
Droplet spray size : less than 50 micrometer (micron)
Spray height: from 175 to 200 mm
Fluidizing velocity : from 0.3 to 1.0 m/s
Bed temperature : from 12 to 80 °C.
If two different kinds of fluidized apparatus would be used, mean residence time of the second step in total can be from 2 to 20 minutes, more preferably, from 2 to 12 minutes.
A coating agent to improve flowability and/or minimize over agglomeration of the detergent composition is added in one or more of the following locations of the instant process: (1) the coating agent can be added directly after fluid bed cooler or fluid bed dryer (2) the coating agent may be added between fluid bed dryer and the fluid bed cooler; and/or (3) the coating agent may be added directly to 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 desirable by consumers in that it permits easy scooping for detergent during 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.

Starting Detergent Materials

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

Detergent Surfactant (Aqueous /Non-aqueous)

The amount of the surfactant of the present process can be from 5% to 60%, more preferably from 12% to 40%, more preferably, from 15 to 35%, in total amount of the final product obtained by the process of the present invention.
The surfactant of the present process, which is used as the above mentioned starting detergent materials in the first step, is in the form of powdered, pasted 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 in 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 in U.S. Patent 4,239,659, Murphy, issued December 16, 1980. Of the surfactants, anionics and nonionics are preferred and anionics are most preferred.
Nonlimiting examples of the preferred anionic surfactants useful in the present invention include the conventional C₁₁-C₁₈ alkyl benzene sulfonates ("LAS"), primary, branched-chain and random C₁₀-C₂₀ 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 where 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 alkyl alkoxy sulfates ("AE_XS"; especially EO 1-7 ethoxy sulfates).
Useful anionic surfactants also include water-soluble salts of 2-acyloxy-alkane-1-sulfonic acids containing from 2 to 9 carbon atoms in the acyl group and from 9 to 23 carbon atoms in the alkane moiety; water-soluble salts of olefin sulfonates containing from 12 to 24 carbon atoms; and beta-alkyloxy alkane sulfonates containing from 1 to 3 carbon atoms in the alkyl group and from 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 alkoxy carboxylates (especially the EO 1-5 ethoxycarboxylates), the C_10-18 glycerol ethers, the C₁₀-C₁₈ alkyl polygtycosides 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 peaked alkyl ethoxylates and C₆-C₁₂ alkyl phenol alkoxylates (especially ethoxylates and mixed ethoxy/propoxy), C₁₀-C₁₈ amine oxides, and the like, can also be included in the overall compositions. The C₁₀-C₁₈ N-alkyl polyhydroxy fatty acid amides can 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 through N-hexyl C₁₂-C₁₈ glucamides can be used for low sudsing. C₁₀-C₂₀ conventional soaps may also be used. If high sudsing is desired, the branched-chain C₁₀-C₁₆ soaps may be used. Mixtures of anionic and nonionic surfactants are especially useful. Other conventional useful surfactants are listed in standard texts.
Cationic surfactants can also be used as a detergent 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 a detergent 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-alkyloxy alkane sulfonates; betaines having the formula R(R¹)₂N⁺R²COO^-, wherein R is a C₆-C₁₈ hydrocarbyl group, preferably a C₁₀-C₁₆ alkyl group or C₁₀-C₁₆ acylamido alkyl 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 acylamidopropyldimethyl betaine; hexadecyl dimethyl betaine; C_12-14 acylamidopropylbetaine; C_8-14 acylamidohexyldiethyl betaine; 4[C_14-16 acylmethylamidodiethylammonio]-1-carboxybutane; C_16-18 acylamidodimethylbetaine; C_12-16 acylamidopentanediethylbetaine; and [C_12-16 acylmethylamidodimethylbetaine. Preferred betaines are C_12-18 dimethyl-ammonio hexanoate and the C_10-18 acylamidopropane (or ethane) dimethyl (or diethyl) betaines; and the sultaines having the formula (R(R¹)₂N⁺R²SO₃- wherein R is a C₆-C₁₈ hydrocarbyl group, preferably a C₁₀-C₁₆ alkyl group, more preferably a C₁₂-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 or, preferably, hydroxyalkylene group. Examples of suitable sultaines include C₁₂-C₁₄ dimethylammonio-2-hydroxypropyl sulfonate, C₁₂-C₁₄ amido propyl ammonio-2-hydroxypropyl sultaine, C₁₂-C₁₄ dihydroxyethylammonio propane sulfonate, and C_16-18 dimethylammonio hexane sulfonate, with C_12-14 amido propyl ammonio-2-hydroxypropyl sultaine being preferred.

Fine Powder

The amount of the fine powder used in the present process, which is used in the first step, can be from 94% to 30%, preferably from 86% to 54%, in total amount of starting material for the first step. The starting fine powder of the present process preferably selected from the group consisting of ground soda ash, powdered sodium tripolyphosphate (STPP), hydrated tripolyphosphate, ground sodium sulphates, aluminosilicates, crystalline layered silicates, nitrilotriacetates (NTA), phosphates, precipitated silicates, polymers, carbonates, citrates, powdered surfactants (such as powdered alkane sulfonic acids) and internal recycle stream of powder occurring from the process of the present invention, wherein the average diameter of the powder is from 0.1 to 500 µm (microns), preferably from 1 to 300 µm (microns), more preferably from 5 to 100 µm (microns). In the case of using hydrated STPP as the fine powder in the present invention, STPP which is hydrated to a level of not less than 50% is preferable. The aluminosilicate ion exchange materials used herein as a detergent builder preferably have both a high calcium ion exchange capacity and a high exchange rate. Without intending to be limited by theory, it is believed that such high calcium ion exchange rate and capacity are a function of several interrelated factors which derive from the method by which the aluminosilicate ion exchange material is produced. In that regard, the aluminosilicate ion exchange materials used herein are preferably produced in accordance with Corkill et al, U.S. Patent No. 4,605,509 (Procter & Gamble).
Preferably, the aluminosilicate ion exchange material is in "sodium" form since the potassium and hydrogen forms of the instant aluminosilicate do not exhibit as high of an exchange rate and capacity as provided by the sodium form. Additionally, the aluminosilicate ion exchange material preferably is in over dried form so as to facilitate production of crisp 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 represents the average particle size diameter of a given 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 from 0.1 micrometer (micron) to 10 micrometer (microns) more preferably from 0.5 micrometer (microns) to 9 micrometer (microns). Most preferably, the particle size diameter is from about 1 micrometer (microns) to about 8 micrometer (microns).
Preferably, the aluminosilicate ion exchange material has the formula Na_z[(AlO₂)_z.(SiO₂)_y]xH₂O wherein z and y are integers of at least 6, the molar ratio of z to y is from 1 to 5 and x is from 10 to 264. More preferably, the aluminosilicate has the formula Na₁₂[(AlO₂)₁₂.(SiO₂)₁₂]xH₂O wherein x is from 20 to 30, preferably 27. These preferred aluminosilicates are available commercially, for example under designations Zeolite A, Zeolite B and Zeolite X. Alternatively, naturally-occurring or synthetically derived aluminosilicate ion exchange materials suitable for use herein can be made 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 of CaCO₃ hardness/gram, calculated on an anhydrous basis, and which is preferably in a range from 300 to 352 mg equivalent of CaCO₃ hardness/gram.

Finely Atomized Liquid

The amount of the finely atomized liquid of the present process can be from 1% to 10% (active basis), preferably from 2% to 6% (active basis) in total amount of the final product obtained by the process of the present invention. The finely atomized liquid of the present process can be selected from the group consisting of liquid silicate, anionic or cationic surfactants which are in liquid form, aqueous or non-aqueous polymer solutions, water and mixtures thereof. Other optional examples for the finely atomized liquid of the present invention can be sodium carboxy methyl cellulose solution, polyethylene glycol (PEG), and solutions of dimethylene triamine pentamethyl phosphonic acid (DETMP),
The preferable examples of the anionic surfactant solutions which 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, and so on.
Cationic surfactants can also be used as finely atomized liquid herein and suitable quatemary 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.
Preferable examples of the aqueous or non-aqueous polymer solutions which can be used as the finely atomized liquid in the present inventions are modified polyamines which comprise a polyamine backbone corresponding to the formula:
having a modified polyamine formula V_(n+1)W_mY_nZ or a potyamine backbone corresponding to the formula:
having a modified polyamine formula V_(n-k+1)W_mY_nY'_kZ, wherein k is less than or equal to n, said polyamine backbone prior to modification has a molecular weight greater than about 200 daltons, wherein
i) V units are terminal units having the formula:
ii) W units are backbone units having the formula:
iii) Y units are branching units having the formula:
and
iv) Z units are terminal units having the formula:

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Other preferable examples of the aqueous or non-aqueous polymer solutions which can be used as the finely atomized liquid in the present invention are polymeric polycarboxylate dispersants which 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, containing no carboxylate radicals such as vinylmethyl ether, styrene, ethylene, etc. is suitable provided that such segments do not constitute more than 40% by weight of the polymer.
Homo-polymeric polycarboxylates which have molecular weights above 4000, such as described next are preferred. Particularly suitable homopolymeric polycarboxylates can be derived from acrylic acid. Such acrylic acid-based polymers which are useful herein are the water-soluble salts of polymerized acrylic acid. The average molecular weight of such polymers in the acid form preferably ranges from above 4,000 to 10,000, preferably from above 4,000 to 7,000, and most preferably from above 4,000 to 5,000. Water-soluble salts of such acrylic add polymers can include, for example, the alkali metal, ammonium and substituted ammonium salts.
Co-polymeric polycarboxylates such as a Acrylic/maleic-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 the acid form preferably ranges 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 will generally range from 30:1 to 1:1, more preferably from 10:1 to 2:1. Water-soluble salts of such acrylic acid/maleic acid copolymers can include, for example, the alkali metal, ammonium and substituted ammonium salts. It is preferable for the above polymer solution to be pre-comptexed with anionic surfactant such as LAS.

Adjunct Detergent Ingredients

The starting detergent material in the present process can include additional detergent ingredients and/or, any number of additional ingredients can be incorporated in the detergent composition during subsequent steps of the present process. These adjunct ingredients include other detergency builders. bleaches, bleach activators, suds boosters or suds suppressors, antitamish and anticorrosion agents, soil suspending agents, soil release agents, germicides, pH adjusting agents, non-builder alkalinity sources, chelating agents, smectite clays, enzymes, enzyme-stabilizing agents and perfumes. See U.S. Patent 3,936,537, issued February 3, 1976 to Baskerville, Jr. et al..
Other builders can be generally selected from the various water-soluble, alkali metal, ammonium or substituted ammonium phosphates, polyphosphates, phosphonates, polyphosphonates, carbonates, borates, polyhydroxy sulfonates, polyacetates, carboxylates, and polycarboxylates. Preferred are the alkali metal, especially sodium, salts of the above. Preferred for use herein are the phosphates, carbonates, C_10-18 fatty acids, polycarboxylates, and mixtures thereof. More preferred are sodium tripolyphosphate, tetrasodium pyrophosphate, citrate, tartrate mono- and di-succinates, and mixtures thereof (see below).
In comparison with amorphous sodium silicates, crystalline layered sodium silicates exhibit a clearly increased calcium and magnesium ion exchange capacity. In addition, the layered sodium silicates prefer magnesium ions over calcium ions, a feature necessary to insure that substantially all of the "hardness" is removed from the wash water. These crystalline layered sodium silicates, however, are generally more expensive than amorphous silicates as well as other builders. Accordingly, in order to provide an economically feasible laundry detergent, the proportion of crystalline layered sodium silicates used must be determined judiciously. Such crystalline layered sodium 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 from 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 disclosed 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 nonphosphorus, inorganic builders are tetraborate decahydrate and silicates having a weight ratio of SiO₂ to alkali metal oxide of from 0.5 to 4.0, preferably from 1.0 to 2.4. Water-soluble, nonphosphorus organic builders useful herein include the various alkali metal, ammonium and substituted ammonium polyacetates, carboxylates, polycarboxylates and polyhydroxy sulfonates. Examples of polyacetate and polycarboxylate builders are the sodium, potassium, lithium, ammonium and substituted ammonium salts of ethylene diamine tetraacetic acid, nitrilotriacetic acid, oxydisuccinic acid, mellitic acid, benzene polycarboxylic acids, and citric acid.
Polymeric polycarboxylate builders are set forth 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 methylene malonic acid. Some of these materials are useful as the water-soluble anionic polymer as hereinafter described, but only if in intimate admixture with the non-soap anionic surfactant
Other suitable polycarboxylates for use herein are the polyacetal carboxylates 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 bringing together under polymerization condition 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 comprising a combination of tartrate monosuccinate and tartrate disuccinate 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. Chelating agents are also described in U.S. Patent 4,683,071, Bush et al., from 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 smectite 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 detergency builders for use herein are enumerated in the Baskerville patent, Column 13, line 54 through Column 16, line 16, and in U.S. Patent 4,663,071, Bush at al, issued May 5, 1987.

Optional Process Steps

Optionally, the process can comprise the step of spraying an additional binder in one or more than one of the first, second and/or the third mixers for the present invention. A binder is added for purposes of enhancing 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, polyvinyl pyrrolidone 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 apparatus which can take a variety of forms including but not limited to conventional screens chosen for the desired particle size of the finished detergent product. Other optional steps include conditioning of the detergent agglomerates by subjecting the agglomerates to additional drying by way of apparatus discussed previously.
Another optional step of the instant process entails finishing the resulting detergent agglomerates by a variety of processes including spraying and/or admixing other conventional detergent ingredients. For example, the finishing step encompasses 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 process, e.g., hardening an aqueous anionic surfactant paste by incorporating a paste-hardening material by using an extruder, prior to the process of the present invention.
In order to make the present invention more readily understood, reference is made to the following examples, which are intended to be illustrative only and not intended to be limiting in scope.

EXAMPLES

Example 1:

The following is an example for obtaining agglomerates having high density, using Lödige KM mixer (KM-600), followed by Schugi FX-160 Mixer, further followed by Fluid Bed Apparatus.
[Step 1] 120 - 260 kg/hr of HLAS (an acid precursor of C₁₁-C₁₈ alkyl benzene sulfonate; 95 % active) at about 45 - 60 °C, is dispersed by the choppers and/or the plows of KM-600 mixer along with 220 kg/hr of powdered STPP (mean particle size of 40 - 75 micrometers (microns)), 160 - 200 kg/hr of ground soda ash (mean particle size of 15 micrometers (microns)), 80- 120 kg/hr of ground sodium sulfate (mean particle size of 15 micrometers (microns)), and 200 kg/hr of internal recycle stream of powder. Serrated plows can be used as mixing elements in the KM mixer. Choppers for the KM mixer can be used to reduce the amount of oversized agglomerates. The condition of the KM mixer is as follows:
Mean residence time: 3-6 minutes
Energy condition : 0.15 - 2 kj/kg
Mixer speed : 100 - 150 rpm
Jacket temperature: 30 - 50°C
[Step 2] The agglomerates from the KM-600 mixer are fed to the Schugi FX-160 mixer. 10 - 20 kg/hr of HLAS (an acid precursor of C₁₁-C₁₈ alkyl benzene sulfonate; 94 - 97% active) is dispersed as finely atomized liquid in the Schugi mixer at 50 to 60°C. 20-80 kg/hr of soda ash (mean particle size of 10 - 20 micrometer (microns)) is added in the Schugi mixer. The condition of the Schugi mixer is as follows:
Mean residence time : 0.2 - 5 seconds
Tip speed: 16 - 26 m/s
Energy condition : 0.15 - 2 kj/kg
Mixer speed : 2000 - 3200 rpm
[Step 3] The agglomerates from the Schugi mixer are fed to a fluid bed drying apparatus for drying, rounding and growth of agglomerates. 20 - 80 kg/hr of liquid silicate (43% solids, 2.0 R) can be also added in the fluid bed drying apparatus at 35°C. The condition of the fluid bed drying apparatus is as follows:
Mean residence time: 4- 8 minutes
Depth of unfluidized bed: 200 mm
Droplet spray size: less than 50 micrometer (micron)
Spray height: 175 - 250 mm (above distributor plate)
Fluidizing velocity : 0.4 - 0.8 m/s
Bed temperature : 40-70 °C]

Example 2:

The following is an example for obtaining agglomerates having high density, using Lödige KM mixer (KM-600), followed by Schugi FX-160 Mixer. then Fluid Bed Apparatus.
[Step 1] 15 kg/hr - 30kg/hr of HLAS (an acid precursor of C₁₁-C₁₈ alkyl benzene sulfonate; 95 % active) at 45 - 60 °C is dispersed by the choppers and/or the plows of KM-600 mixer along with 220 kg/hr of powdered STPP (mean particle size of 40 - 75 micrometer (microns)), 160 - 200 kg/hr of ground soda ash (mean particle size of 15 micrometer (microns)), 80- 120 kg/hr of ground sodium sulfate (mean particle size of 15 micrometer (microns)), and 200 kg/hr of internal recycle stream of powder. Serrated plows can be used as mixing elements in the KM mixer. Choppers for the KM mixer can be used to reduce the amount of oversized agglomerates. The condition of the KM mixer is as follows:
Mean residence time: 3- 6 minutes
Energy condition : 0.15 - 2 kj/kg
Mixer speed : 100 - 150 rpm
Jacket temperature: 30 - 50°C
[Step 2] The agglomerates from the KM-600 mixer are fed to the Schugi FX-160 mixer. 10 - 25 kg/hr of neutralized AE₃S liquid (25 - 28 % active) is dispersed as finely atomized liquid in the Schugi mixer at 30-40°C. 20-80 kg/hr of soda ash is added in the Schugi mixer. The condition of the Schugi mixer is as follows:
Mean residence time : 0.2 - 5 seconds
Tip speed: 16 - 26 m/s
Energy condition : 0.15 - 2 kj/kg
Mixer speed : 2000 - 3200 rpm
[Step 3] The agglomerates from the Schugi mixer are fed to a fluid bed drying apparatus for drying, rounding and growth of agglomerates. 20 - 80 kg/hr of liquid silicate (43% solids, 2.0 R) can be also added in the fluid bed drying apparatus at 35°C. The condition of the fluid bed drying apparatus is as follows:
Mean residence time : 2- 4 minutes
Depth of unfluidized bed : 200 mm
Droplet spray size : less than 50 micrometer (micron)
Spray height: 175 - 250 mm (above distributor plate)
Fluidizing velocity : 0.4 - 0.8 m/s
Bed temperature : 40 - 70 °C]

Example 3:

The following is an example for obtaining agglomerates having high density, using Lödige KM mixer (KM-600), followed by Fluid Bed Apparatus for further agglomerations.
[Step 1] 250 - 270 kg/hr of aqueous coconut fatty alcohol sulfate surfactant paste (C₁₂-C₁₈, 71.5% active), 40 - 80kg/hr of HLAS (an acid precursor of C₁₁-C₁₈ alkyl benzene sulfonate; 94 - 97% active) is fed to a KM-600 mixer along with 220 kg/hr of powdered STPP (mean particle size of 40 - 75 micrometer (microns)), 160 - 200 kg/hr of ground soda ash (mean particle size of 15 micrometer (microns)), 80- 120 kg/hr of ground sodium sulfate (mean particle size of 15 micrometer (microns)), and 200 kg/hr of internal recycle stream of powder. The surfactant paste is fed at 40 to 52°C, and the powders are fed at room temperature. Choppers for the KM mixer can be used to reduce the amount of oversized agglomerates. The condition of the KM mixer is as follows:
Mean residence time: 3- 6 minutes
Energy condition: 0.15 - 2 kj/kg
Mixer speed : 100 - 150 rpm
Jacket temperature: 30 - 50°C
[Step 2] The agglomerates from the KM mixer are fed to a fluid bed drying apparatus for drying, rounding and growth of agglomerates. 20 - 80 kg/hr of liquid silicate (43% solids, 2.0 R) can be also added in the fluid bed drying apparatus at 35°C. The condition of the fluid bed drying apparatus is as follows:
Mean residence time : 2- 4 minutes
Depth of unfluidized bed : 200 mm
Droplet spray size: less than 50 micrometer (micron)
Spray height: 175 - 250 mm (above distributor plate)
Fluidizing velocity: 0.4 - 0.8 m/s
Bed temperature: 40 - 70 °C
Having thus described the invention in detail, it will be obvious 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 to be considered limited to what is described in the specification.

Claims

A non-tower process for preparing 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 diameter from 0.1 to 500 micrometer (microns), in a mixer with choppers attached wherein conditions of the mixer include (i) from 0.5 to 15 minutes of mean residence time and (ii) from 0.15 to 7 kj/kg of energy condition, wherein first agglomerates and excessive fine powder are formed;

(a') spraying finely atomized liquid onto the first agglomerates in a mixer wherein conditions of the mixer include (i) from 0.2 to 5 seconds of mean residence time, (ii) from 10 to 30 m/s of tip speed, and (iii) from 0.15 to 5 kj/kg of energy condition, wherein excessive 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 fluid bed dryer and a fluid bed cooler wherein conditions of each of the fluidizing apparatus include (i) from 1 to 10 minutes of mean residence time, (ii) from 100 to 300 mm of depth of unfluidized bed, (iii) not more than 50 micrometer (micron) of droplet spray size, (iv) from 175 to 250 mm of spray height, (v) from 0.2 to 1.4 m/s of fluidizing velocity and (vi) from 12 to 100 °C of bed temperature, and wherein a coating agent selected from the group consisting of aluminosilicates, silicates, carbonates and mixtures thereof is added to the second step either : directly after the fluid bed dryer or fluid bed cooler; and/or between the fluid bed dryer and fluid bed cooler; and/or directly to the fluid bed dryer.
The process according to claim 1 wherein said surfactant is selected from the group consisting of anionic surfactant, nonionic surfactant, cationic surfactant, zwitterionic, ampholytic and mixtures thereof.
The process according to claim 1 wherein said surfactant is selected from the group consisting of alkyl benzene sulfonates, alkyl alkoxy sulfates, alkyl ethoxylates, alkyl sulfates, coconut fatty alcohol sulfates and mixtures thereof.
The process according to claim 1 wherein an aqueous or non-aqueous polymer solution is dispersed with said surfactant in step (a).
The process according to claim 1 wherein the fine powder is selected from the group consisting of soda ash, powdered sodium tripolyphosphate, hydrated tripolyphosphate, sodium sulphates, aluminosilicates, crystalline layered silicates, phosphates, precipitated silicates, polymers, carbonates, citrates, nitrilotriacetates, powdered surfactants and mixtures thereof.
The process according to claim 1 wherein an internal recycle stream of powder from the fluidizing apparatus is further added to step (a).
The process according to 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.