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Title:
LOW DENSITY BUILDER AND DETERGENT PARTICLES VIA HIGH SHEAR AGGLOMERATION
Document Type and Number:
WIPO Patent Application WO/2014/003845
Kind Code:
A1
Abstract:
A method of manufacturing an agglomerate comprising particles bound together with a polymeric binder comprising agglomerating a mixture of water; organic acid particles; a water- soluble, partially neutralized polycarboxylate polymer or copolymer, having about 30% to about 90% of its carboxylic acid groups in free acid form; and a water-soluble carbonate for a period of time sufficient to react the organic acid and free acid groups of the polycarboxylate polymer with the carbonate to produce gas during the agglomeration process, thereby producing fully-soluble agglomerates having void spaces therein and a lowered bulk density. Optionally, the agglomerate also includes an anionic detersive surfactant to form a low density detergent builder.

Inventors:
KENNEDY DAVID (US)
Application Number:
PCT/US2013/031179
Publication Date:
January 03, 2014
Filing Date:
March 14, 2013
Export Citation:
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Assignee:
AMCOL INTERNATIONAL CORP (US)
International Classes:
C11D3/00; C11D3/10; C11D3/20; C11D3/37; C11D7/12; C11D7/26; C11D11/04; C11D17/06
Foreign References:
US6455490B12002-09-24
US5574004A1996-11-12
EP0628627A11994-12-14
US6214785B12001-04-10
US5480577A1996-01-02
US5494599A1996-02-27
US5712242A1998-01-27
US6281188B12001-08-28
Attorney, Agent or Firm:
ANDRESON, Richard, H. et al. (Gerstein & Borun LLP233 S. Wacker Drive, 6300 Willis Towe, Chicago IL, US)
Download PDF:
Claims:
CLAIMS

1. A method of manufacturing an agglomerate comprising particles bound together with a polymeric binder comprising:

agglomerating a mixture of water; organic acid particles; a water-soluble, partially neutralized polycarboxylate polymer or copolymer, having about 30% to about 90% of its carboxylic acid groups in free acid form; and a water-soluble carbonate for a period of time sufficient to react the organic acid and free acid groups of the polycarboxylate polymer with the carbonate to produce gas during the agglomeration process, thereby producing fully-soluble agglomerates having void spaces therein and a lowered bulk density.

2. The method of claim 1, further including the step of drying the agglomerated particles to a moisture content less than about 20 wt.%.

3. The method of claim 1 or claim 2, wherein the agglomerated particles are dried to a moisture content of about 5 wt.% to about 15 wt.%.

4. The method of any of claims 1-3, wherein the organic acid comprises citric acid and/or maleic acid.

5. The method of any of claims 1-4, wherein the polycarboxylate polymer or copolymer is a polymer or copolymer of one or more compounds, containing 30% to 90% of their carboxylic acid groups in free acid form, selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, glutamic acid, 2-acrylamido-2- methylpropane, fumaric acid, mesoconic acid, mixtures and copolymers thereof.

6. The method of any of claims 1-5, wherein the polycarboxylate polymer is a partially neutralized, fully water-soluble polycarboxylate having about 30% to about 80% of its carboxylic acid groups in free acid form.

7. The method of any of claims 1-6, wherein the polycarboxylate polymer or copolymer has a number average molecular weight in the range of about 3,000 to about 20,000.

8. The method of any of claims 1-7, wherein the partially neutralized

polycarboxylate has a number average molecular weight in the range of about 3,000 to about 20,000.

9. The method of claim 8, wherein the polycarboxylate polymer or copolymer has a number average molecular weight in the range of about 4,000 to about 10,000.

10. The method of claim 8, wherein the partially neutralized polycarboxylate has a number average molecular weight in the range of about 4,000 to about 10,000.

11. The method of any of the preceding claims, wherein the agglomerated builder particles have a median particle size in the range of about 200μιη to about 2,000μιη.

12. The method of claim 11, wherein the agglomerated builder particles have a median particle size in the range of about 200μιη to about 1,500μιη.

13. The method of any of the preceding claims, wherein the organic acid source has a particle size in the range of about 50μιη to about Ι,ΟΟΟμιη.

14. The method of any of the preceding claims, wherein the organic acid source has a particle size in the range of about ΙΟΟμιη to about 850μιη.

15. A fully- soluble, detergent builder comprising agglomerated particles of a polycarboxylate polymer, one or more alkali metal carbonates, and an organic acid source having a bulk density of about 450 grams/liter to about 700 grams/liter.

The detergent builder of claim 15, made by the process of claim 1

17. The detergent builder of claim 15, having a median particle size in the range of about 200μιη to about 2,000μιη.

18. The detergent builder of claim 17, having a median particle size in the range of about 200μιη to about 1,500μιη.

19. The detergent builder of any of claims 15-18, wherein the agglomerated particles have a bulk density of about 350 grams/liter to about 700 grams/liter.

20. The detergent builder of an of claims 15-18, wherein the agglomerated particles have a bulk density of about 350 grams/liter to about 600 grams/litter

21. The detergent builder of any of claims 15-18, wherein the agglomerated particles have a bulk density of about 350 grams/liter to about 550 grams/liter.

22. The detergent builder of claim 15 having a total soluble salt content of about 70 wt.% to about 90 wt.%, wherein about 40 wt.% to about 90 wt.% of the soluble salts are selected from the group consisting of an alkali metal carbonate; an alkali metal bicarbonate, and an alkali metal sesquicarbonate and the builder comprises about 2 wt.% to about 12 wt.% polycarboxylate co-builder/binder; and about 2 wt.% to about 12 wt.% water.

23. The detergent builder of claim 21, wherein the soluble salts comprise sodium or potassium carbonate, sodium or potassium bicarbonate or sodium or potassium sesquicarbonate.

24. A detergent builder and detergent agglomerate, possessing both detersive and builder components, processed via agglomeration of an anionic surfactant and the builder of claim 15 in the form of a surfactant paste, with the agglomerate having a bulk density less than 600 grams/liter.

25. A detergent agglomerate comprising an anionic acidic detersive surfactant and a partially neutralized acidic polycarboxylate builder component processed via agglomeration to effect in-situ neutralization of the acidic anionic surfactant and the partially neutralized acidic polycarboxylate builder components.

26. The detergent agglomerate of claim 25 wherein the agglomerate has a density less than 600 g/1.

27. A method of manufacturing detergent and builder agglomerated particles comprising shearing together an acidic anionic surfactant and a partially acidic, partially neutralized polycarboxylate builder component to effect in-situ gas evolution within the agglomerate particles to provide increased particle void space and lowered bulk density to the agglomerated particles.

28. The detergent agglomerate of claim 25, wherein the bulk density of the resulting detergent and builder particles is from about 300 g/1 to about 400 g/1.

Description:
LOW DENSITY BUILDER AND DETERGENT PARTICLES VIA HIGH SHEAR

AGGLOMERATION

FIELD

[0001] Disclosed, in one embodiment, is a route to a low bulk density detergent builder particle, and in another embodiment, to a low density detergent containing a low density builder, the compositions of both embodiments being manufactured via high shear agglomeration of a polymeric builder solution or structured anionic surfactant and polymeric builder paste.

[0002] More specifically, the invention relates to a process whereby agglomerates of low bulk density possessing builder, or both detergent builder and an anionic surfactant having detersive properties, are realized via high shear agglomeration of a polymeric builder solution or structured polymer/surfactant paste.

[0003] The present invention enables a way to produce free-flowing, fully water soluble builder particles, or fully soluble detergent and builder particles of high detergent activity, each having comparable bulk density to conventional spray dried powder detergents.

BACKGROUND AND PRIOR ART

[0004] Typically, detergent agglomerates are prepared using a process of either spray-drying an aqueous detergent slurry or pre-mixing of detergent raw materials and subsequently agglomerating blended powders using liquid surfactant(s) binders.

[0005] In the spray drying process, an aqueous slurry of detergent components, such as builders and surfactants, is prepared in a crutcher. Typically, the water content of such slurries, whilst formulation dependent, are of the order of 35-50 wt. . The slurry is heated and spray dried to produce porous granules of low bulk density and good water solubility. Bulk density of spray dried laundry detergents is typically in the range of 300-400g/l. However, significant drawbacks to the spray drying process are the high energy input, appreciable capital costs of spray drying towers and potential for VOC emissions.

[0006] Agglomeration entails pre-mixing powdered detergent components and agglomerating said powders using liquid surfactant/binder(s). Agglomeration processes tend to generate higher bulk density products than the spray-dried route, with agglomeration a preferred route for production of higher density compact powder detergents. [0007] Where reference is made to employing agglomeration techniques to produce low density detergent particles (typically, having bulk densities less than about 600 g/1 or less than about 650g/l), such systems tend to incorporate low density builder compontents such as zeolite 4A, which, whilst contributing to lowering of detergent bulk density, imparts a degree of water insolubility to the finished article.

[0008] It would therefore be most desirable to have a route to a low density builder and/or a low density detergent and builder particle via an agglomeration process, which is neither reliant on low density additives such as zeolite materials nor incurs the excessive capital expenditure and energy consumption associated with conventional spray-dried detergent manufacturing practices.

[0009] The art is replete with disclosures of detergent compositions processed via

agglomeration of structured surfactant pastes. For example, Goovaerts et al, U.S. Pat. No.

5,494,599, discloses a detergent composition containing at least one anionic surfactant and an effective amount of a dry detergency powder. Whilst the composition is produced via agglomeration, it does not result in the formation of a low density particle, with typical bulk density in excess of 600g/l referenced.

[0010] In another disclosure, Aouad et al, U.S. Pat. No. 5,712,242 teach a process of making high active granular detergents. A three component composition based on surfactant, chelant and copolymer is disclosed, which, when employed as agglomeration binders for zeolite and sodium carbonate, produces detergent particles with high detersive loading. However, no reference is made to the attainment of low density detergent particles via this route.

[0011] Kandasamy et al, U.S. Patent No. 6,281,188 outlines a process for manufacturing low density detergent granules via a non-tower route. The use of water absorbing species to harden a surfactant paste is disclosed with typical bulk density of less than 600g/l claimed.

[0012] Ranges may be expressed herein as from "about" or "approximately" one particular value and/or to "about" or "approximately" another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. SUMMARY

[0013] In accordance with the compositions and methods described herein, a route to a fully water soluble builder having a bulk density of about 350 g/1 to about 600 g/1; and/or detergent and builder particle possessing both builder and detersive properties, which, when prepared via an agglomeration process, has a bulk density of about 300 to about 400g/l.

LOW DENSITY BUILDER

[0014] Low bulk density characteristics are realized via a two-fold in-situ reaction:

[0015] 1) Reaction of an organic acid source with a carbonate and/or bicarbonate precursor to generate carbon dioxide gas and facilitate agglomerate particle expansion

[0016] 2) Use of a partially neutralized polycarboxylate co-builder that functions in dual capacities (1) as an agglomeration binder and (2) a reactant for reaction with a carbonate, bicarbonate and/or sesquicarbonate builder component(s) for additional gas formation, and further bulk density reduction.

[0017] 3) In-situ further neutralization of the partially neutralized polycarboxylate co-builder when contacted under conditions of high shear agglomeration with the carbonate, bicarbonate and/or sesquicarbonate builder component(s) results in additional carbon dioxide evolution and further reduction in agglomerate bulk density.

[0018] 4) Optional drying of the agglomerated builder results in free-flowing, crisp, fully water-soluble agglomerated detergent builder particles having a typical bulk density of about 350 to about 600 g/1.

[0019] By varying the extent of the neutralization of the polycarboxylate co- builder/binder/reactant starting material, thereby adjusting the amount of CO 2 that is evolved during the high shear agglomeration process, the bulk density of agglomerated builder particles can be tailored to closely match low bulk density detergent compositions.

[0020] The process produces a builder agglomerate of lower than expected bulk density via high shear agglomeration route.

LOW DENSITY DETERGENT AND BUILDER

[0021] Low bulk density characteristics are realized via in-situ neutralization reactions : [0022] 1) Use of acidic anionic surfactant and partially acidic polycarboxylate with the latter acting as a surfactant structuring aid

[0023] 2) Intimate mixing of acidic anionic surfactant and partially acidic polycarboxylate produces a structured paste of low water content and high detergent activity

[0024] 3) In-situ neutralization of said structured surfactant paste when contacted under conditions of high shear agglomeration with alkaline builder salt(s) results in carbon dioxide evolution and lowering of agglomerate bulk density

[0025] 4) Drying of aforementioned agglomerate to produce a free-flowing, crisp, fully water soluble detergent particle with typical bulk density of 300-400g/l.

[0026] The process includes the steps of agglomerating a structured

polycarboxylate/surfactant paste with alkaline salt(s) in a mixer to effect in-situ neutralization of both an acidic surfactant and a partially acidic polycarboxylate, to obtain agglomerates. Such reactions evolve carbon dioxide gas which facilitates particle expansion and lowers product bulk density. In the detergent embodiment, it is a combination of both reactions which results in the attainment of a finished agglomerate with bulk density of 300-400g/l, which is akin to a conventional spray dried detergent particle.

DETAILED DESCRIPTION (BUILDER)

[0027] Described herein is a process for manufacturing a detergent builder agglomerate product of lower than expected bulk density by a high shear agglomeration process.

[0028] The process includes the steps of agglomerating a partially neutralized polycarboxylate co-builder/binder/reactant, an organic acid/reactant source and a carbonate, bicarbonate and/or sesquicarbonate reactant, preferably a carbonate, and/or sesquicarbonate reactant, more preferably a carbonate/bicarbonate/sesquicarbonate/sulfate blend, in a shear mixer to obtain agglomerates, wherein both 1) the reaction of the organic acid with the

carbonate/bicarbonate/sesquicarbonate/sulphate source and 2) the reaction of the un-neutralized portion of the polycarboxylate co-builder with the

carbonate/bicarbonate/sesquicarbonate/sulphate source generates gas, such as carbon dioxide, within the agglomerate. [0029] The interaction under high shear, of the un-neutralized portion of the polycarboxylate and the carbonate source provides a mechanism for controlling and additionally lowering of, the bulk density of the final agglomerate via gas formation, such as carbon dioxide gas, within the agglomerate, by choosing a degree of neutralization of the polycarboxylate binder/reactant.

[0030] It is a combination of both reactions which results in the attainment of a finished agglomerate having a bulk density in the range of about 350 to about 600 g/1.

PROCESS

[0031] Starting materials are fed into a high shear agglomeration mixer (e.g., Eirich, Lodige CB, Schugi, or similar equipment) and dry blended for a period of about 1 to 60 seconds.

[0032] The starting materials preferably include a partially neutralized polycarboxylate binder/reactant having about 30% to about 90% of its carboxylic acid groups in free acid form, an organic acid reactant source, such as citric acid, and a carbonate reactant source, such as sodium carbonate, sodium bicarbonate and/or sodium sesquicarbonate. In addition, the formulation, optionally, may also include such salts as are typically found in detergent formulations, such as sodium sulphate.

[0033] A partially neutralized polycarboxylate co-builder/binder/reactant liquid is introduced into an agglomeration shear mixer and mixing is continued until agglomeration has occurred. Typically, the mixing period is between 1 and 60 seconds.

[0034] Under conditions of high shear granulation, two reactions prevail, both of which result in the generation of carbon dioxide gas which creates a void volume within the agglomerated particles.

1) The organic acid source reacts with carbonate source; and

2) The partially neutralized (about 10 mole % to less than about 70 mole % neutralized - leaving about 30 mole % to about 90 mole %, preferably about 30 mole % to about 85 mole % free acid) polycarboxylate co-builder/binder/reactant, is further neutralized by the carbonate source resulting in additional C0 2 generation, in-situ.

[0035] As a result of the combined effect of the above reactions, detergent builder agglomerates with low bulk density (about 350 to about 600 g/1) are produced when a polycarboxylate co-builder/binder/reactant having a regulated free acid content is employed. [0036] As shown in Table 1, infra, it has been found that if the polycarboxylate is fully neutralized (FN), the detergent builder agglomerates have a bulk density greater than 600 g/1. If the polycarboxylate source is not neutralized at all - 100% free acid (FA), the detergent builder agglomerates again have a bulk density greater than 700 g/1. It has been found that the polycarboxylate starting material should contain about 30 mole % to about 90 mole % free acid, preferably about 30 mole % to about 85 mole % free acid, more preferably about 30 mole % to about 80 mole % free acid to achieve a bulk density in the range of about 350 g/1 to about 600 g/1-

[0037] The builder agglomerates produced by this process preferably include a

polycarboxylate co-builder content from about 0.1 wt.% to about 20 wt.%, more preferably from about 2% to about 15% and, most preferably from about 5 wt.% to about 13 wt.%. The carbonate and/or bicarbonate loading of the agglomerates should be about 10 wt.% to about 70 wt.%, preferably 30 wt.% to about 60 wt.%.

[0038] In the preferred embodiment, the detergent builder agglomerates preferably have a median particle size of about 200μιη to about 2000μιη, more preferably 200μιη to about

PARTIALLY NEUTRALIZED POLYCARBOXYLATE POLYMER CO- BUILDER/BINDER/REACTANT

[0039] The partially neutralized polycarboxylate co-builder/binder/reactant is preferably completely water soluble and in the form of an aqueous solution with a typical viscosity at ambient temperature ranging from about lOOcPs to about 5000cPs and will contain no less than about 20% water, more typically at least about 30% by weight water.

[0040] The partially neutralized polycarboxylate co-builder/binder/reactant, may be, for example, a homopolymer or a copolymer (containing two or more co-monomers).

[0041] Suitable polycarboxylate are those which have detergent builder properties, and impart a dispersive effect on soil and insoluble materials in the washing solution.

[0042] Particularly suitable polycarboxylate starting materials are polymers and copolymers of any one or more of the following: acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, glutamic acid, 2-acrylamido-2-methylpropane, fumaric acid or mesoconic acid. [0043] More suitable polycarboxylates can be a copolymer of two of the above detailed monomers, with preference to one of said monomers being acrylic acid in a molar majority (having a molar concentration greater than any other monomer in the copolymer), and in another embodiment, the molar concentration of acrylic acid in the copolymer is a polymer of acrylic acid, in a molar majority, and maleic anhydride in a molar minority (having a molar

concentration less than any other monomer in the copolymer). In the preferred embodiment, the copolymer contains about 60 mole percent to about 95 mole percent acrylic acid and about 5 mole percent to about 40 mole percent maleic anhydride, most preferably about 70 to about 95 mole percent acrylic acid and about 5 to about 30 mole percent maleic anhydride.

[0044] The partially neutralized polycarboxylate should have a number average molecular weight of, for example, about 1,000 to 70,000, preferably about 2,000 to 20,000, more preferably about 3,000 to about 15,000, even more preferably about 4,000 to about 10,000, and most preferably about 4,000 to about 8,000.

[0045] The polycarboxylate should be employed in a partially free acid form, in that only about a 10 mole % to about less than 70 mole % fraction of the monomeric carboxylic acid groups have been neutralized. More preferably, the partially neutralized polycarboxylate co- builder/binder/reactant, should contain between about 30% and 90% of original free acid functionalities, and more preferably have between 30% and 80% of their carboxylic acid groups un-neutralized (in free acid form).

CARBONATE SOURCE

[0046] Preferably the carbonate source is a carbonate, bicarbonate and/or sesquicarbonate, with suitable examples being the alkaline earth and alkali metal carbonates, including sodium or potassium carbonate, bicarbonate and sesquicarbonate, and any mixtures thereof.

[0047] The carbonate, bicarbonate and sesquicarbonate preferably have a mean particle size of about 20μιη or greater, preferably about 30μιη or greater, most preferably of about 40-150μιη. Preferably, the carbonate, bicarbonate and/or sesquicarbonate should be present in the agglomerate builder in an amount of about 10 wt.% to about 80 wt.%, preferably about 30 wt.% to about 70 wt.%

ORGANIC ACID SOURCE [0048] The organic acid source is preferably water soluble and can be employed as anhydrous or can be in a partially hydrated form. For purposes of control of hygroscopic tendencies, anhydrous forms are preferred.

[0049] Preferred organic acids include one or more selected from: maleic, citric, fumaric, aspartic, glutaric, tartaric, malonic, succinic or adipic acid, and mixtures thereof. Citric acid and/or maleic acid are the most preferred organic acids.

[0050] The preferred organic acid should have a mean particle size which confers a high degree of reactivity under granulation conditions. It has been determined that the organic acid source preferably has a particle size distribution from about 50μιη to about ΙΟΟΟμιη, and more preferably from about ΙΟΟμιη to about 850μιη.

LOW DENSITY BUILDER COMPOSITION

[0051] The builder described above that is a post manufacture addition to detergent compositions includes a total soluble salt content of about 70 wt. % to about 90 wt. , wherein about 40 wt. % to about 90 wt. % of the soluble salts are in the form of an alkali carbonate; about 2 wt. % to about 12 wt. % polycarboxylate co-builder; and about 2 wt. % to about 12 wt. % water for solubility and bulk density control. The builder composition comprises water soluble salts which may be, for example, an alkali metal carbonate, bicarbonate, sesquicarbonate, silicate and/or sulphate. Preferably, this salt will be sodium carbonate, sodium bicarbonate, and/or sodium sesquicarbonate, and more preferably, a combination of one or more carbonates together with a sulphate salt.

[0052] The water-soluble alkaline carbonate may be, for example, an alkali metal carbonate, bicarbonate or sesquicarbonate, preferably sodium or potassium carbonate, bicarbonate or sesquicarbonate, and most preferably sodium carbonate. A combination of more than one carbonate compound may be used, e.g., sodium carbonate, sodium bicarbonate and/or sodium sesquicarbonate. In one embodiment, the total water-soluble alkali metal carbonate content in the finished agglomerates may be, for example, about 40 to about 90 wt. , preferably about 50 wt.% to about 90 wt.%, based on the total weight of water-soluble salts in the builder

composition. If a combination of alkali metal carbonate and bicarbonate is used as the water- soluble carbonate, then the alkali metal carbonate, e.g., sodium carbonate, is preferably used in an amount of about 40 to about 70 wt. % and the alkali metal bicarbonate, e.g., sodium bicarbonate, in an amount of about 0.1 to about 15 wt. %, based on the total weight of water- soluble salts in the builder composition.

[0053] If employed, then the sodium sesquicarbonate component is preferably used in an amount of about 5% to 25 wt. % based on the total weight of water soluble salts in the builder composition.

[0054] The organic acid source may be for example, maleic or citric acid. Preferably, citric acid will be employed at about 1 wt.% to about 15 wt.% based on total weight of salts in the builder composition. Most preferably, the citric acid content should be in the range of about 3 wt.% to about 10 wt. % of the builder composition.

EXAMPLES I-VI

[0055] These examples illustrate one embodiment of the invention. Specifically, a low bulk density detergent and builder agglomerate is manufactured in a batch mode using an Eirich LI high shear granulation mixer.

[0056] Mixer is charged with dry powders (light sodium carbonate, sodium bicarbonate, citric acid, and anhydrous sodium sulphate) and subjected to a period of dry blending for about 1 to 60 seconds.

[0057] Liquid binder, partially neutralized polycarboxylate, is added under high shear to form wet agglomerates which are subsequently dried to a moisture content of about 2 to 12 wt.% in a fluidized bed dryer.

[0058] The agglomerated product is screened to retain a fraction having a particle size in the range of about 250μιη to about 1400μιη which is subsequently measured for loose bulk density.

TABLE 1

Agglomerate Component Example Example Example Example Example Example Example Example

(grams) I Π ΠΙ rv V VI VII VIII

Light Sodium Carbonate 120.0 120.0 120.0 120.0 120.0 120.0 120.0 120.0

Sodium Bicarbonate 18.0 18.0 18.0 18.0 18.0 18.0 18.0 18.0

Sodium Sesquicarbonate 60.0

Anhydrous Citric Acid, -30/+100 mesh* — — — — 21.0 21.0 21.0 21.0

Anhydrous Citric Acid, -200 mesh* — 21.0 — 21.0 — — — —

Tri-Sodium Citrate Dihydrate, -30/+100 21.0 — 21.0 — — — — — mesh*

Anhydrous Sodium Sulphate 90.0 90.0 90.0 90.0 90.0 90.0 90.0 30.0

50% Active Polycarboxylate, FN 60.0 60.0 — — 60.0 — — —

50% Active Polycarboxylate, PN — — 60.0 60.0 — 60.0 — 60.0

50% Active Polycarboxylate, FA — — — — — — 60.0 —

Eirich LI Mixer Conditions

Powder Premix Time (sees) 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00

Liquid Agglomeration Time (sees) 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0

Impeller Tip Speed (ms ') 8-20 8-20 8-20 8-20 8-20 8-20 8-20 8-20

Bulk Density (g/1) 900 720 700 610 640 500 680 400

*ASTM mesh sizes

EXAMPLES I-VII

[0059] Example I - Agglomerates based on non-reactive tri-sodium citrate di-hydrate salt and fully neutralized polycarboxylate polymer (FN; pH 7-9).

[0060] Example II - Agglomerates based on fine grained anhydrous citric acid (-200 mesh) and fully neutralized polycarboxylate polymer (FN; pH 7-9).

[0061] Example III - Agglomerates based on non-reactive tri-sodium citrate di-hydrate salt and partially neutralized polycarboxylate polymer (PN; pH 2-4).

[0062] Example IV - Agglomerates based on fine grained anhydrous citric acid (-200 mesh) and partially neutralized polycarboxylate polymer (PN; pH 2-4).

[0063] Example V - Agglomerates based on preferred citric acid grading (-30/+ 100 mesh) and fully neutralized polycarboxylate acid polymer (FN; pH 7-9).

[0064] Example VI - Agglomerates based on preferred citric acid grading (-30/+ 100 mesh) and partially neutralized polycarboxylate polymer (PN; pH 2-4).

[0065] Example VII - Agglomerates based on preferred citric acid grading (-30/+ 100 mesh) and free acid form of polycarboxylate polymer (FA; pH 1-2). [0066] Example VIII - Agglomerates based on preferred citric acid grading (-30/+ 100 mesh), partial replacement of sodium sulphate by sodium sesquicarbonate and partially neutralized polycarboxylate polymer (PN; pH 2-4).

[0067] As can be seen in Table 1, the bulk density of the detergent builder agglomerates can be adjusted through exploitation of both organic acid source and degree of neutralization of polycarboxylate polymer binder/reactant.

[0068] When a partially neutralized polycarboxylate binder/reactant is used in conjunction with an organic acid source of specified particle size i.e. Example VI, a significant reduction in product bulk density is realized as a result of the combined processes of organic acid polymer- carbonate interaction and polycarboxylate-carbonate neutralization steps, respectively.

[0069] In addition, using same approach and replacing part of the sodium sulphate component by sodium sesquicarbonate, a further decrease in bulk density is realized.

[0070] When only one of these reactions occurs, e.g. Example V, (polycarboxylate polymer unreactive in fully neutralized form), the bulk density of the finished agglomerate is over 20% higher.

[0071] Similarly, when a partially neutralized polycarboxylate is employed in conjunction with a sodium salt of citric acid, tri- sodium citrate di-hydrate, Example III, the bulk density is again significantly higher than that of Example VI.

DETAILED DESCRIPTION (DETERGENT AND BUILDER)

[0072] Described herein is a process for manufacturing a detergent containing a detergent builder, as an agglomerate, that has a lower than expected bulk density by virtue of high shear agglomeration used in the agglomeration process.

PROCESS

[0073] Surfactant paste is prepared by feeding HLAS (linear alkylbenzene sulphonic acid, 96%) and a partially acidic polycarboxylate (typical water content 40-60%) into a high speed mixer or extruder arrangement to effect intimate mixing and generate paste type consistency.

[0074] The water content of the structured surfactant paste will be about 10 to about 30 wt.%. [0075] The paste is subsequently charged to a second mixer containing a pre-weighed quantity of alkaline builder salts, as described above in the builder embodiment, such as sodium carbonate and sodium bicarbonate and added under high shear until granulation complete.

[0076] Wet agglomerates are further processed via a drying step so as to reduce moisture content to a desired range of about 1% and about 15% by weight, based on the total weight of the agglomerates, and further lower bulk density. On exiting agglomeration mixer, wet

agglomerates preferably contain between 10% and 15% by weight of water.

[0077] Drying can be achieved via a fluidized bed process, whereby wet agglomerates are subjected to warm flow of air to reduce moisture content to desired level. Preferably, fluidized bed drier inlet air temperature will be in the range of about 50°C to about 200°C, ideally about 50°C to about 150°C.

[0078] The detergent and builder agglomerates produced by this route preferably possess an anionic surfactant content from about 25% to about 45%, more preferably from about 25% to 43% and, most preferably from about 25% to 40%.

[0079] In addition, the detergent and builder agglomerates produced by this route preferably possess a polycarboxylate co-builder content from about 4% to about 20%, more preferably from about 4% to about 16% and, most preferably from about 4% to about 12%.

[0080] The process provides combined detergent and builder agglomerates having a median particle size of about 200μιη to about 2000μιη, and more preferably from about 200μιη to about 1400μπι.

PARTIALLY ACIDIC SODIUM POLYCARBOXYLATE

[0081] Chosen from a wide range of organic polymers which function as builders to improve detergency, the desired polycarboxylate is preferably in the form of an aqueous solution with typical viscosity at ambient temperature ranging from lOOcPs to 5000cPs. The concentration of the aqueous polycarboxylate solution influences water content of the structured paste and, as such, should be as low as is feasible, possibly without incurring polycarboxylate solubility or stability issues. To that end, commercially available solutions based on no less than 40% water should be employed, with typical polycarboxylate solutions at water contents of 40-50% most desirable. [0082] The polycarboxylate co-builder may be, for example, a homo-polymer or co-polymer (consisting of two co-monomers).

[0083] Suitable polycarboxylates for this formulation are those which possess detergent builder behaviour, and impart a dispersive effect on soil and insoluble materials in the washing solution.

[0084] Particularly suitable polycarboxylates are composed of acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, glutamic acid, 2 acrylamido-2-methylpropane, fumaric acid or mesoconic acid.

[0085] More suitable polycarboxylates can be a copolymer of two of the above detailed monomers, with preference to one of said monomers being acrylic acid in a molar majority (having a molar concentration greater than any other monomer in the copolymer), and in another embodiment, the molar concentration of acrylic acid in the copolymer is a polymer of acrylic acid, in a molar majority, and maleic anhydride in a molar minority (having a molar

concentration less than any other monomer in the copolymer). In the preferred embodiment, the copolymer contains about 60 mole percent to about 95 mole percent acrylic acid and about 5 mole percent to about 40 mole percent maleic anhydride, most preferably about 70 to about 95 mole percent acrylic acid and about 5 to about 30 mole percent maleic anhydride.

[0086] The polymeric polycarboxylate should possess a number average molecular weight of, for example, about 1,000 to 70,000, preferably about 2,000 to 20,000, more preferably about 3,000 to about 15,000, even more preferably about 4,000 to about 10,000, and most preferably about 4,000 to about 8,000.

[0087] The polycarboxylate should be employed in a substantially free acid form, in that only a fraction of the monomeric carboxylic groups have been subject to neutralization. More specifically, the polycarboxylate binder should possess between 40% and 90% of original free acid functionalities, and more favourably between 50% and 90% of free acidity.

ANIONIC SURFACTANTS

[0088] Suitable anionic detersive surfactants include linear C10-C13 alkylbenzene sulphonic acid, such as those supplied by STEP AN under the tradename BIO-SOFT® LA Acid or those supplied by UNGER Surfactants under the tradename UFACID® KW (high 2-phenyl) or UFACID® K (low 2-phenyl). Particularly suitable are the linear alkylbenzene sulphonates (LABS); alkyl sulphonates (AS); alkyl ether sulphonates (AES); and combinations thereof.

[0089] Other anionic surfactant types, such as alkyl ether sulphonates containing from about 1 to about 7 units of ethylene oxide per molecule and wherein the alkyl group contains from about 10 to 18 carbon atoms, can be used in conjunction with linear alkylbenzene sulphonic acid surfactant. Preferred is the sodium salt of alkyl ether sulphonate containing from about 1 to about 4 units of ethylene oxide. As with partially acidic sodium polycarboxylate, the water content of any secondary surfactant additive should be limited. For this reason, use of sodium alkyl ether sulphonate solutions having a water content of about 20 to about 35% by weight are most preferred.

[0090] Non-ionic surfactants, such as the fatty alcohol ethoxylates, are generally not suitable for processing at the temperatures used in the agglomeration process described herein since they possess lower thermal stability. However, while usually void of non-ionic surfactants, non-ionic surfactants which do not thermally decompose at the processing temperatures employed may be included in amounts of about 5 wt% to about 20 wt%.

BUILDER SALTS

[0091] Preferably the builder salt(s) source is a carbonate and/or bicarbonate, with suitable examples being the alkaline earth and alkali metal carbonates, including sodium and potassium carbonate, bicarbonate and sesquicarbonate, and any mixtures thereof.

[0092] The carbonate, bicarbonate and sesquicarbonate preferably have a mean particle size of about 5μιη or greater, preferably about 20μιη or greater, most preferably about 25 to about

WATER CONTENT OF THE STRUCTURED SURFACTANT PASTE

[0093] The activity of the aqueous surfactant paste is at least about 50% and can go up to about 95%.

[0094] Preferred activities are about 70% to about 95% and about 70% to about 90%. Lower water content is preferred in order to maximize delivery of active components (surfactant(s) and polymeric builder) during the granulation/agglomeration step. Furthermore, the detersive (an ionic) surfactant comprises from about 50% to about 80% of the structured paste, preferably from about 50% to about 75%. The polycarboxylate component should comprise from about 5% to about 25% of the structured paste, preferably from about 5% to about 20%, with the balance being water.

AGGLOMERATE DRYING TEMPERATURE

[0095] Use of conventional powder drying equipment such as a fluid bed drier is preferred. Inlet air temperature must be controlled to ensure no thermal degradation of the composition. It has been found that inlet air temperature at, or in excess of about 90°C to about 150°C, favorably contributes to lowering particle bulk density through expansion of entrained gas inside wet agglomerates.

LOW DENSITY DETERGENT PARTICLE COMPOSITION

[0096] The low density detergent particle includes a total soluble salt content of about 40 wt. % to about 70 wt. %, wherein about 45 wt. % to about 65 wt. % of the soluble salts are in the form of an alkali carbonate; about 4 wt. % to about 15 wt. % of one or more polycarboxylate co builders; and about 25 wt. % to about 40 wt. % of anionic surfactant(s). The builder composition comprises water soluble salts which may be, for example, an alkali metal carbonate, bicarbonate, sesquicarbonate, silicate and/or sulphate. Preferably, this salt will be sodium carbonate, and more preferably, a combination of two or more of these compounds.

[0097] The water-soluble alkaline carbonate may be, for example, an alkali metal carbonate, bicarbonate or sesquicarbonate, preferably sodium or potassium carbonate, bicarbonate or sesquicarbonate, and most preferably sodium carbonate. A combination of more than one of such compounds may be used, e.g., sodium carbonate and sodium bicarbonate. The total water-soluble alkaline carbonate may be present in an amount, for example, of about 40 to about 70 wt. %, preferably about 45 to about 65 wt. %, based on the total weight of water-soluble salts in the builder composition. If a combination of alkali metal carbonate and bicarbonate is used as the water-soluble carbonate, then the alkali metal carbonate, e.g., sodium carbonate, is preferably used in an amount of about 45 to about 60 wt. % and the alkali metal bicarbonate, e.g., sodium bicarbonate, in an amount of about 0.1% to about 15 wt. %, based on the total weight of water- soluble salts in the builder composition. [0098] The polycarboxylate co-builder may be, for example, a homo-polymer or co-polymer (consisting of two co-monomers).

[0099] Suitable polycarboxylate for this formulation are those which impart a dispersive effect on soil and insoluble materials in the washing solution.

[00100] Particularly suitable polycarboxylates are composed of acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, glutamic acid, 2 acrylamido-2-methylpropane, fumaric acid or mesoconic acid.

[00101] In a preferred embodiment, polymeric polycarboxylate should possess a number average molecular weight of, for example, about 1,000 to 70,000, preferably about 2,000 to 20,000, more preferably about 3,000 to about 15,000, even more preferably about 4,000 to about 10,000, and most preferably about 4,000 to about 8,000.

[0100] The polycarboxylate should be employed in a substantially free acid form, in that only a fraction of the monomeric carboxylic groups have been subject to neutralization. More specifically, the polycarboxylate binder should possess about 20% to about 90% of original free acidity, and more favorably about 50% to about 90% of free acidity.

EXAMPLES

[0101] These Examples illustrate one manufacturing process to make the detergent and builder agglomerates. Specifically, the process in batch mode in a laboratory scale high shear mixer to produce a low bulk density detergent agglomerate. The detergent agglomerates prepared by this process contain anionic surfactant salt and sodium polycarboxylate builder, coming from dry neutralization of both acidic anionic surfactant and partially acidic polycarboxylate species.

[0102] In these Examples, the mixer is charged with powders, in this case light sodium carbonate (ex. SOLVAY Chemicals) and sodium bicarbonate (ex. TATA Chemicals), and operated at a slow speed for 20 seconds to achieve uniform blending.

[0103] A surfactant-polycarboxylate paste is prepared in a separate high shear mixer unit. On mixing, the reactant mixture viscosifies to form a stiff paste. Paste is added to mixer containing powders and subjected to high shear mixing until granulation has occurred. TABLE 2

Example 1

[0104] The structured admixture is an aqueous paste of HLAS and sodium polycarboxylate (10% molar neutralization, direct pH 2.84, % NVS 49.2) at weight ratio of 1.0 to 0.50 respectively. Water content of surfactant-polycarboxylate paste is 17%.

[0105] In this example, granulation was unsuccessful owing to the reactivity of the acidic structured paste toward alkaline substrate. With low polycarboxylate molar neutralization, granule expansion due to carbon dioxide evolution was excessive, and agglomerates produced were of poor quality and appearance.

Example 2

[0106] This Example is similar to Example 1. The structured surfactant is an aqueous paste of HLAS and sodium polycarboxylate (30% molar neutralization, direct pH 3.88, % NVS 49.1) at weight ratio of 1.0 to 0.50 respectively. Water content of surfactant-polycarboxylate paste is 17%. [0107] In this example, granulation generated uniform, free-flowing agglomerates of desired quality.

[0108] The agglomerates were dried in a fluid bed drier with inlet air temperature of 100°C, and subsequently screened to retain 1400μιη-250μιη fraction.

[0109] The agglomerates made in this Example have a detergent activity of 35%,

polycarboxylate activity of 9% and a loose bulk density of 330g/l.

Example 3

[0110] As with previous Examples, but structured paste is a mixture of HLAS and

polycarboxylate, with the latter of higher level of neutralization (50% molar neutralization, direct pH 4.85, % NVS 50.7).

[0111] Free-flowing agglomerates generated as per Example 2, above.

[0112] The agglomerates made in this Example have a detergent activity of 35%,

polycarboxylate activity of 9% and a bulk density of 446g/l.

Example 4

[0113] As with previous Examples, but polycarboxylate employed of higher level of neutralization (75% molar neutralization, direct pH 5.51, % NVS 50.2).

[0114] Free-flowing agglomerates generated as per previous Example.

[0115] The agglomerates made in this Example have a detergent activity of 35%,

polycarboxylate activity of 9% and a bulk density of 421g/l.

Example 5

[00102] As with previous Examples, but polycarboxylate employed was fully neutralized sodium salt (100% molar neutralization, direct pH 7.80, % NVS 50.1).

[0116] Free-flowing agglomerates generated as per previous Examples detailed.

[0117] The agglomerates made in this example have a detergent activity of 35%,

polycarboxylate activity of 9% and a bulk density of 441g/l.

[0118] As is evident from the Examples listed, the processing of a low density detergent builder particles so as to exhibit loose bulk density below 400g/l and thus mimic that of a conventional spray dried detergent particle, can be achieved through combined use of acidic anionic surfactant and selected polycarboxylate of required acidity, as detailed in Example 2. [0119] With the description of the invention as outlined it is expected that those skilled in the art will be familiar with the various changes which can be applied without departing from the scope of the invention, and as such, the invention should not be considered limited in merely what is described in these specifics.