WO2023041467A1

WO2023041467A1 - Process for preparing a spray dried detergent particle

Info

Publication number: WO2023041467A1
Application number: PCT/EP2022/075230
Authority: WO
Inventors: Abraham Chacko; Girish Kumar; Sharavan KUMAR; Kunal Shankar PAWAR; Nadeem Shaikh; Satyendra Prasad SINGH
Original assignee: Unilever Ip Holdings B.V.; Unilever Global Ip Limited; Conopco, Inc., D/B/A Unilever
Priority date: 2021-09-15
Filing date: 2022-09-12
Publication date: 2023-03-23

Abstract

The present invention relates to a process for preparing of a particulate, free flowing detergent particle by a slurry making and spray drying technique. In particular it relates to the process for preparing a slurry with lower alkalinity for the production of spray dried laundry detergent particle. Accordingly, it is one object of this invention to provide a process for preparing a spray dried detergent particle where the spray dried particle has excellent powder properties and provides a wash liquor with lower alkalinity and provides good stain removal performance without being harsh on hands and fabrics.The present inventors have found that a spray-dried detergent particle having an aluminium hydrate, alkaline builder at certain specific levels provides for excellent powder properties with extended shelf life without getting caked and the spray-dried particles provides desired pH in wash solution to provide for good stain removal performance without being harsh on the hands or the fabrics.

Description

PROCESS FOR PREPARING A SPRAY DRIED DETERGENT PARTICLE

Field of the invention

The present invention relates to a process for preparing a particulate, free flowing detergent particle by a slurry making and spray drying technique. The spray-dried particle is suitable for use as a solid laundry detergent composition, or for incorporation into a solid laundry detergent composition.

Background of the invention

Typically, granular laundry detergent composition is prepared by spray-drying. In spraydrying process the laundry detergent components, such as surfactants and builders are mixed with around 20% to 50% by weight water to form an aqueous slurry, the aqueous slurry is maintained at temperatures ranging from 60°C to 85°C and then spray-dried in a spray-drying tower.

Many consumers launder fabrics by hand. In addition to good cleaning performance these consumers desire for laundry composition that provide mildness to the skin and a desirable feel while washing. In the past, such milder compositions have been formulated by lowering the alkalinity of the composition. This necessitates significantly reducing or completely removing the alkaline ingredients such as sodium carbonate and sodium silicate. Yet another advantage of reducing carbonate-based builder is the reduction in ash build-up on fabrics and machine parts under medium and hard water conditions.

It is well-known that, within limits, detergency tends to improve as pH is increased. Hence it may be desired to maintain the pH of the finished detergent composition relatively unchanged. Carbonate salts and silicate salts provide a wash liquor with desired pH of about 10.5. In addition to influencing the pH of the wash liquor, carbonate salt and silicate salt also function as effective builders to sequester calcium and magnesium ions present in water. Besides these benefits, presence of carbonate salt provides good physical attributes to the spray-dried detergent particle. Such physical characteristics include lower caking tendency and good flowability of the powder during extended shelf storage period. Any reduction in the levels of carbonate salt will directly affect the abovementioned properties. Silicate salt which is typically a sodium salt of silicate is generally considered a critical ingredient in spray dried particulate detergent compositions and serves to provide stability and integrity to the detergent particles formed during the spray-drying operation. Attempts at reducing or eliminating sodium silicate have caused deterioration of flow properties and the spray-dried particles were found to be prone to caking. Lowering the silicate levels also impact the viscosity and flow behaviour of the slurry and it was observed that the slurry was difficult to pump due to gelation of slurry.

The present inventors have further observed that a spray dried detergent particle prepared from a slurry with below 8 wt.% sodium carbonate levels and silicate salt (sodium silicate) levels below 7 wt.% may form into spray-dried detergent particle which has good powder properties when freshly prepared, but under storage conditions these spray-dried particle exhibits severe caking tendency.

It is thus a challenge to provide a spray dried detergent particle with good powder properties such as free-flowability and extended storage life while providing compositions which are milder on hand and fabrics without adversely affecting the cleaning performance.

US 2002/0123450 A1 (Oki et al.) discloses a process for preparing a base particle which involves a step of spray drying a slurry having zeolite, water soluble salt and a surfactant in an amount of 5 wt.% by weight of the slurry or less. The zeolite in the process may be obtained by mixing an aluminium source in presence of an alkaline earth metal compound.

US 3011977 (Bernhard Raecke, 1961) discloses a detergent composition which eliminates or substantially reduces the irritation of the skin by the addition of complex aluminium compounds. The composition includes phosphate builder. US 3951877 A (Okumura Osamu et. al., 1976) discloses a heavy-duty granular detergent composition having 10 wt.% to 60 wt.% sodium citrate, 5 wt.% to 40 wt.% non-soap anionic surfactant and 0.1 wt.% to 10 wt.% inorganic aluminium salt.

Thus, there is a need to provide a granular laundry detergent composition which is less harsh on the hands of the user and on fabrics without adversely affecting the cleaning performance and the free-flowing powder properties over extended storage life.

It is thus an object of the present invention to provide a process for preparing a detergent solution for a spray-dried detergent particle which provides for incorporating a carbonate builder and silicate salt at levels which provides good cleaning performance and good powder properties.

It is yet another object of the present invention to provide a process for preparing a detergent solution for a spray-dried detergent particle having non-phoshpate builders and which provides good cleaning performance and good powder properties.

It is yet another object of the present invention to provide a process for preparing a detergent slurry which upon spray drying provides for a spray-dried detergent particle having lower reserve alkalinity and a desired pH for providing good cleaning performance.

It is a further object of this invention to provide a process for preparing a granular detergent composition wherein the spray-dried particles are characterized by a relatively better structure, and which do not have an increased tendency towards caking.

Summary of the invention

The present inventors have found that a spray dried detergent particle having a solubilized aluminium hydrate and specific levels of an alkaline builder wherein the alkaline builder is selected from alkali metal carbonate salt, alkali metal silicate salt or mixtures thereof provides for excellent powder properties and extended shelf life without getting caked. It is also surprisingly found that the spray-dried particle provides desired pH in wash solution required for good stain removal performance without being harsh on the hands or the fabrics.

The spray dried detergent particle according to the present invention incorporates optimum amounts of alkaline builders, particularly alkali metal silicate, alkali metal carbonate or mixtures thereof. The spray-dried detergent particle has good powder properties and is free-flowing even after extended storage period.

Further the spray-dried detergent particle has lowered reserve alkalinity levels while maintaining the pH levels required for optimum cleaning performance thereby providing better fabric care benefits.

The process according to the present invention provides a spray-dried detergent particle which in presence of low levels of carbonate builder provides good storage stability, good powder properties and is less harsh on the hands or on the fabric. The low levels of carbonate builder ensures that the spray-dried detergent particle is less harsh on the hands and when prepared according to the process of the present invention having a solubilized aluminium hydrate provides good powder properties in addition to maintaining good cleaning performance. Preferably the spray-dried particle has low no phosphate builder.

According to a first aspect of the present invention, disclosed is a process for preparing a spray dried detergent particle, said process comprising the steps of:

(i) solubilizing aluminium hydrate in an aqueous mixture by mixing aluminium hydrate with an alkaline source and where the aqueous mixture has a pH from 12 to 14;

(ii) adding an alkaline builder selected from the group consisting of (i) alkali metal carbonate salt (ii) alkali metal silicate salt or mixtures thereof to form an aqueous slurry; wherein the aqueous slurry comprises a solubilized aluminium hydrate, detersive surfactant, and alkaline builder; and wherein the alkali builder comprises from 3 wt.% to 25 wt.% alkali metal carbonate salt and wherein the aqueous slurry has a pH ranging from 10 to 12,

(iii) spray-drying said aqueous slurry to form said spray dried detergent particle.

As used herein the term “reserve alkalinity” refers to the grams of NaOH/100 grams when titrated till 10 pH with H2SO4.The alkali reserve is determined by an acid/base titration of a solution with 0.5 mol/l sulphuric acid till pH of 10.00.

The reserve alkalinity of the spray-dried detergent particle to pH 10 is from 1.5 to 5 grams NaOH/100g. Preferably less than 5.0 grams NaOH/100g, preferably less than 4 grams NaOH/100g, still preferably 3.5 grams NaOH/100g, further preferably less than 2 grams NaOH/100g.

Detailed description of the invention

According to a first aspect of the present invention disclosed is a process for preparing a spray-dried detergent particle, the process comprising the steps as described herein below.

Step (i): Solubilizing aluminium hydrate in an aqueous mixture

According to the first aspect of the present invention disclosed is a process of solubilizing aluminium hydrate by contacting the aluminium hydrate with an alkaline source in an aqueous mixture.

Aluminium hydrate:

The aluminium hydrate is preferably preformed or formed in-situ. Aluminium hydrate is commercially available in solid form from various suppliers, the preformed aluminium hydrate comprises 99 wt.% to 100 wt.% aluminium hydrate. Aluminium hydrate may also be available in the form of a pre-dissolved solution.

Alternately the aluminium hydrate may be formed in-situ by reacting a acid with an alkali metal aluminate salt or by reacting a strong base with an aluminium salt. Preferably the acid is an inorganic acid, still preferably linear alkyl benzene sulphonic acid. Preferably the strong base is alkali metal hydroxide, alkaline earth metal hydroxide or mixtures thereof. Preferably the strong base is sodium hydroxide potassium hydroxide, calcium hydroxide, magnesium hydroxide or mixtures thereof. More preferably the strong base is sodium hydroxide. Preferably the aluminium salt is aluminium sulphate which is reacted with a strong base to form in-situ aluminium hydrate. Aluminium hydrate is insoluble in water. By the term “insoluble” it is meant that the aluminium hydrate has a solubility in water of 0.0001g/mL or less under room conditions. Addition of the alkaline source to the aluminium hydrate provides for at least partial solubilization of aluminium hydrate.

Alkaline source:

Preferably the alkaline source is an alkali metal hydroxide, alkali metal silicate, alkali metal carbonate or mixtures thereof. Preferably the alkaline source is an alkali metal hydroxide, still preferably sodium hydroxide. Preferably the sodium hydroxide is in the form of an aqueous solution having a solid content ranging from 30 wt.% to 50 wt.%. Sodium Hydroxide may also be in solid form which can be pre diluted to form a solution of Sodium hydroxide before addition to the aqueous mixture.

According to the present invention aluminium hydrate is solubilized in an aqueous mixture by adding an alkaline source wherein the pH of the aqueous mixture after addition of the alkaline source ranges from 12 to 14. It is essential that the pH of the aqueous mixture is from 12 to 14 for solubilizing the aluminium hydrate in the aqueous mixture.

Aqueous mixture:

Preferably the aqueous mixture comprises a detersive surfactant. Suitable detersive surfactant includes anionic, nonionic, cationic, amphoteric, zwitterionic detersive surfactant or mixtures thereof. Suitable detersive surfactant may be linear or branched, substituted or un-substituted. The detersive surfactant may be derived from petrochemical material or is bioderived. Preferably the detersive surfactant present in the aqueous mixture is an anionic surfactant. Anionic detersive surfactant: The aqueous mixture preferably includes an anionic detersive surfactant. The detersive anionic surfactant is either pre-neutralized and added into the aqueous mixture or a liquid acid form of the anionic surfactant is added to the aqueous mixture and neutralized in-situ. Alternately, the acid form of the anionic surfactant may be partly neutralized and thereafter added into the aqueous mixture such that the remaining un-neutralized part of the liquid acid form of the anionic surfactant is neutralized in-situ in the aqueous mixture. Pre-neutralized surfactant is commercially available in solid form or in the form of paste. Preferably the detersive surfactant is added to the aqueous mixture before addition of the aluminium hydrate. In some embodiments the detersive surfactant is added to the aqueous mixture after the solubilization of the aluminium hydrate.

When the detersive surfactant is added into the aqueous mixture in the form of a partly neutralized surfactant, the partly neutralized anionic surfactant is preferably prepared by a neutralization process which involves the step of mixing a liquid acid form of the anionic surfactant and a neutralizing agent to form a partially neutralized solution; preferably the neutralizing agent is an alkali metal hydroxide, more preferably sodium hydroxide, wherein the amount of alkali metal hydroxide neutralizing agent is sufficient to react with a portion of liquid acid anionic surfactant precursor to form in-situ anionic surfactant salt. The neutralized anionic surfactant formed by neutralizing the acid form with the alkali metal hydroxide neutralizing agent preferably contributes from 28 parts to 98 parts of the total anionic surfactant by weight present in the spray-dried particle. On addition of alkaline source to the partly neutralized anionic surfactant in the aqueous mixture, the remaining unreacted acid form of the anionic surfactant reacts with the alkaline source to form fully neutralized salt form of the anionic surfactant. In one embodiment of the present invention a fully neutralized anionic surfactant is added to the aqueous mixture. In this embodiment the liquid acid anionic surfactant precursor is reacted with an alkali metal hydroxide to form fully neutralized anionic surfactant salt before addition to the aqueous mixture. More preferably the liquid acid precursor of the anionic surfactant is partly or fully neutralized in-situ. It is most preferred that the detersive surfactant is present when the aluminium hydrate is solubilized by adding an alkaline source. The order of addition is to contact the preneutralized detersive surfactant or the acid detersive surfactant precursor with water followed by adding the alkaline source and then adding the aluminium hydrate. Preferably the part or full neutralization may be carried out in the same vessel by contacting the acid precursor form of the anionic surfactant with an aqueous solution of neutralizing agent (alkali metal hydroxide) to form the neutralized anionic surfactant salt.

Preferably the detersive surfactant is an anionic surfactant. Suitable anionic detersive surfactant include sulphonate and sulphate surfactant. Suitable sulphonate surfactant include methyl ester sulphonate, alpha olefin sulphonate, alkyl benzene sulphonate, especially alkyl benzene sulphonate, preferably C10 to C14 alkyl benzene sulphonate. A preferred detersive anionic surfactant is linear alkyl benzene sulphonate, where the alkyl chain has 5 to 20 carbon atoms, more preferably the linear alkylbenzene sulphonate surfactant has a C12 to C18 alkyl group. Suitable alkyl benzene sulphonate (LAS) is obtainable, preferably obtained, by sulphonating commercially available linear alkyl benzene (LAB); suitable LAB includes low 2-phenyl LAB, other suitable LAB includes high 2-phenyl LAB, such as those supplied by Sasol under the tradename Hyblene®.

Suitable sulphate surfactant includes alkyl sulphate, preferably Cs to C18 alkyl sulphate, or predominantly C12 to C18 alkyl sulphate. A preferred sulphate detersive surfactant is alkyl alkoxylated sulphate, preferably alkyl ethoxylated sulphate, preferably a Cs to Cis alkyl alkoxylated sulphate, preferably a Cs to Cis alkyl ethoxylated sulphate, preferably the alkyl alkoxylated sulphate has an average degree of alkoxylation of from 0.5 to 20, preferably from 0.5 to 10, preferably the alkyl alkoxylated sulphate is a Cs to Cis alkyl ethoxylated sulphate having an average degree of ethoxylation of from 0.5 to 10, preferably from 0.5 to 5, more preferably from 0.5 to 3 and most preferably from 0.5 to 1.5. The alkyl sulphate, alkyl alkoxylated sulphate and alkyl benzene sulphonate may be linear or branched, substituted or un-substituted and may be derived from petrochemical material or biomaterial. Other suitable anionic detersive surfactants include, soaps, alkyl ether carboxylates. Suitable anionic detersive surfactants may be in salt form, suitable counter-ions include sodium, calcium, magnesium, amino alcohols, and any combinations thereof. A preferred counterion is sodium. One or more anionic surfactant may be present in the spray-dried detergent particle.

Suitable non-ionic detersive surfactants are selected from the group consisting of: Cs to Cis alkyl ethoxylates, such as, NEODOL® non-ionic surfactants from Shell; Cs to C12 alkyl phenol alkoxylates wherein preferably the alkoxylate units are ethyleneoxy units, propyleneoxy units or a mixture thereof; C12 to C18 alcohol and Ce to C12 alkyl phenol condensates with ethylene oxide/propylene oxide block polymers such as Pluronic® from BASF; alkyl polysaccharides, preferably alkyl polyglycosides; methyl ester ethoxylates; polyhydroxy fatty acid amides; ether capped poly(oxyalkylated) alcohol surfactants and mixtures thereof.

Suitable non-ionic detersive surfactants are alkyl polyglucoside and/or an alkyl alkoxylated alcohol. Suitable non-ionic detersive surfactants include alkyl alkoxylated alcohols, preferably Cs to Cis alkyl alkoxylated alcohol, preferably a Cs to Cis alkyl ethoxylated alcohol, preferably the alkyl alkoxylated alcohol has an average degree of alkoxylation of from 1 to 50, preferably from 1 to 30, or from 1 to 20, or from 1 to 10, preferably the alkyl alkoxylated alcohol is a Cs to Cis alkyl ethoxylated alcohol having an average degree of ethoxylation of from 1 to 10, preferably from 1 to 7, more preferably from 1 to 5 and most preferably from 3 to 7. The alkyl alkoxylated alcohol can be linear or branched and substituted or un-substituted. Suitable nonionic detersive surfactants include secondary alcohol-based detersive surfactants.

Zwitterionic surfactant: Suitable zwitterionic detersive surfactants include amine oxides and/or betaines.

One or more detersive surfactant may be present in the spray-dried particle according to the present invention. The surfactant preferably includes those which are thermally stable during processing conditions of a spray-drying tower with inlet air temperature ranging from 250°C to 500°C and those which are chemically stable at the pH conditions typically present in a spray-drying slurry. Non-limiting examples of the anionic surfactant includes the ones mentioned above. Preferably the aqueous slurry includes LAS. In some embodiments the detersive surfactant present in the aqueous slurry is a combination of LAS and alkyl ether sulphate, still preferably a combination of LAS and SLES (1 EO to 3EO). The aqueous mixture may also preferably include a combination of anionic surfactant and non-ionic surfactant as the co-surfactant.

Preferably after the solubilization of aluminium hydrate the aqueous mixture includes i) preferably 5 wt.% to 45 wt.% detersive surfactant; ii) 0.8 wt.% to 4.8 wt.% aluminium hydrate; iii) preferably 7 wt.% to 31 wt.% alkali metal silicate salt; iv) 0 wt.% carbonate salt; v) 50 wt.% to 60 wt.% water.

The aqueous mixture includes aluminium hydrate in solubilized form. Preferably the solubility of aluminium hydrate in the aqueous mixture is more than 0.0001 g/mL under room conditions. According to the present invention aluminium hydrate is solubilized in the aqueous mixture by adding an alkaline source wherein the pH of the aqueous mixture after addition of the alkaline source is in the range from 12 to 14. The pH range from 12 to 14 provides for solubilizing the aluminium hydrate in the aqueous mixture.

In order to ensure the solubilization of the aluminium hydrate it is preferred that the aqueous mixture includes less than 3 wt.% organic acid, organic acid include those selected from the group consisting of hydroxycarboxylic acid, polycarboxylic acid or mixtures thereof. More preferably the aqueous mixture includes less than 1 wt.% organic acid, still preferably 0 wt.% organic acid. Examples of the organic acid generally used in laundry composition includes tartaric acid, citric acid, malic acid, glycolic acid or lactic acid, more commonly the organic acid is citric acid.

Step (ii): Adding an alkaline builder to form an aqueous slurry

The next step involves adding an alkaline builder to the aqueous mixture to form an aqueous slurry comprising the solubilized aluminium hydrate, alkaline builder and a detersive surfactant. The alkaline builder is selected from the group consisting of alkali metal carbonate, alkali metal silicate or mixtures thereof.

Alkali metal carbonate builder:

The alkaline builder includes an alkali metal carbonate builder. The alkali metal carbonate builder is present in the aqueous slurry in amount ranging from 3 wt.% to 15 wt.%. Preferred alkali carbonates are sodium and/or potassium carbonate of which sodium carbonate is particularly preferred. It is further preferred that sodium carbonate makes up at least 75 wt.%, more preferably at least 85 wt.% and even more preferably at least 90 wt.% of the total weight of the carbonate salt.

Preferably the aqueous slurry includes from 3 wt.% to 15 wt.% alkali metal carbonate builder, still preferably from 3 wt.% to 13 wt.% alkali metal carbonate builder. Preferably the amount of alkali metal carbonate builder in the aqueous slurry is not less than 3 wt.%, still preferably not less than 5 wt.%, more preferably not less than 8 wt.%, still more preferably not less than 10 wt.%, but typically not more than 14 wt.%, preferably not more than 13.5 wt.% or still preferably not more than 13 wt.%.

Alkali metal silicate salt:

The alkaline builder may be an alkali metal silicate salt builder. Preferably the alkali metal silicate is a soluble silicate. Soluble silicates are common ingredients in the laundry detergent compositions. The alkali metal silicate salt preferably has a weight ratio of SiC^ /hO, within the range of 1.6 to 3.3 more preferably 1.6 to 2.4, and most preferably 2.0 to 2.85 wherein M is an alkali metal. The alkali metal silicate salt employed is in the form of an aqueous solution, generally having 30 wt.% to 45 wt.% solid content. Preferably the alkali metal silicate salt may be selected from the group consisting of sodium silicate, potassium silicate, sodium-potassium double silicate or mixtures thereof. Preferably the alkali metal silicate salt is water-soluble. Preferably the alkali metal silicate salt employed is sodium silicate. Preferably the sodium silicate has a weight ratio, SiO2:Na2O within the range of 1.6 to 3.3 more preferably 1.6 to 2.4, and most preferably 2.0 to 2.85. Preferably the aqueous slurry includes from 4 wt.% to 15 wt.% alkali metal silicate salt builder, still preferably from 4 wt.% to 13.5 wt.% alkali metal silicate salt builder.

Preferably the amount of alkali metal silicate salt builder in the aqueous slurry is not less than 4.5 wt.%, still preferably not less than 5 wt.%, more preferably not less than 8 wt.%, still more preferably not less than 10 wt.%, but typically not more than 14 wt.%, preferably not more than 13.5 wt.% or still preferably not more than 13 wt.%.

Filler:

Preferably the aqueous slurry includes a filler selected from the group consisting of sodium sulphate, sodium chloride, calcium carbonate, magnesium carbonate, calcite, dolomite, or mixtures thereof. The filler acts as a balancing ingredient and can be a neutral inorganic salt or mineral, preferably sodium sulphate or sodium chloride. In one preferred embodiment, the filler is sodium chloride. In another preferred embodiment, the filler is a mixture of sodium sulphate and sodium chloride.

At this stage after the addition of the alkaline builder, the resulting aqueous slurry preferably includes:

(i) from 2 wt.% to 35 wt.% detersive surfactant;

(ii) from 0.06 wt.% to 4 wt.% solubilized aluminium hydrate;

(iii) an alkaline builder selected from the group consisting of: preferably from 4 wt.% to 15 wt.% alkali metal silicate, 3 wt.% to 15 wt.% alkali metal carbonate builder or mixtures thereof; and,

(iv) from 25 wt.% to 40 wt.% water.

Preferably the amount of detersive surfactant in the aqueous slurry is not less than 3 wt.%, still preferably not less than 5 wt.%, more preferably not less than 8 wt.%, still more preferably not less than 10 wt.%, but typically not more than 34 wt.%, preferably not more than 33 wt.% or still preferably not more than 32 wt.%.

Preferably the amount of solubilized aluminium hydrate in the aqueous slurry is not less than 0.08 wt.%, still preferably not less than 1 wt.%, more preferably not less than 1.5 wt.%, still more preferably not less than 2 wt.%, but typically not more than 3.5 wt.%, preferably not more than 3 wt.% or still preferably not more than 2.5 wt.%.

Preferably the amount of water in the aqueous slurry is not less than 22 wt.%, still preferably not less than 24 wt.%, more preferably not less than 25 wt.%, but typically not more than 34 wt.%, preferably not more than 38 wt.% or still preferably not more than 37 wt.%.

Inorganic phosphate builders for example sodium orthophosphate, pyrophosphate and tripolyphosphate, hexametaphosphate are preferably present at relatively low levels, for example less than 5 wt.%, still preferably less than 3 wt.%, further preferably less than 1 wt.%. Preferably the aqueous slurry includes 0 wt.% phosphate builder. Most preferably the spray-dried detergent particle prepared from the process according to the first aspect of the present invention is substantially free of inorganic phosphate builder. By substantially free it is meant that the spray dried detergent particle prepared according to the process of the first aspect does not include any deliberately added inorganic phosphate builder.

Zeolite builders used in most commercial particulate detergent compositions is zeolite A. Advantageously, aluminium zeolite P (zeolite MAP) described and claimed in EP 384 070A (Unilever) may be used. Zeolite MAP is an alkali metal aluminosilicate of the P type having a silicon to aluminium ratio not exceeding 1.33, preferably not exceeding 1.15, and more preferably not exceeding 1.07. Zeolite builders are preferably present at relatively low levels, for example less than 5 wt.%, still preferably less than 3 wt.%, further preferably less than 1 wt.% in the aqueous slurry. Preferably the aqueous slurry includes 0 wt.% zeolite builder. Most preferably the spray-dried detergent particle prepared from the process according to the first aspect of the present invention is substantially free of zeolite builders. By “substantially free” it is meant that the spray dried detergent particle prepared according to the process of the first aspect does not include any deliberately added inorganic zeolite builder. Optionally the aqueous slurry may include an organic builder. Non-limiting examples of organic builder include polycarboxylate polymers such as polyacrylates, acrylic/maleic copolymers, and acrylic phosphinates; monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono-, di-and tri succinates, carboxymethyloxysuccinates, carboxymethyloxymalonates, dipicolinates, hydroxyethyliminodiacetates, alkyl- and alkenylmalonates and succinates; and sulphonated fatty acid salts. Preferably the organic builder is selected from monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono-, di-and trisuccinates, carboxymethyloxysuccinates, carboxymethyloxymalonates, dipicolinates, hydroxyethyliminodiacetates, alkyl- and alkenylmalonates and succinates, more preferably alkali metal citrate, most preferably it is sodium citrate. Organic builders may be used in minor amounts as supplement to carbonate salt builder. When present the organic builder is present in an amount of less than 3 wt.%, more preferably less than 1 wt.%, still preferably 0 wt.%.

Preferred supplementary organic builders are suitably used in amounts of from 0.1 wt.% to 30 wt.%, preferably from 10 wt.% to 25 wt.%; and acrylic polymers, more especially acrylic/maleic copolymers, suitably used in amounts of from 0.5 wt.% to 15 wt.%, preferably from 1 wt.% to 10 wt.%.

Powder flow properties may be improved by the incorporation of a small amount of a powder structurant, for example, a fatty acid (or fatty acid soap), a sugar, an acrylate or acrylate/maleate polymer. One preferred powder structurant is fatty acid soap, suitably present in an amount of from 1 wt.% to 5 wt.%.

Further optional ingredients may be added to the aqueous slurry which includes but are not limited to, any one or more of the following: soap, sequestrants, calcium chloride, sodium bicarbonate, other inorganic salts, fluorescers, foam controllers, foam boosters, dyes, anti-redeposition agents, colourants, shading dyes and combinations thereof. Preferably the anti-redeposition agents are alkali metal salt of carboxymethyl cellulose. The optional ingredient may be preferably hydrotropes or viscosity modifiers or dispersants selected from the non-limiting group consisting of sodium toluene sulphonate, sodium cumene sulphonate, sodium xylene sulphonate or mixtures thereof.

Preferably a filler may be added to the aqueous slurry before spray-drying. The filler may be added either before the addition of the alkaline builder or after the addition of the alkaline to the aqueous mixture to form the aqueous slurry. Preferably the filler is added after the addition of the alkaline builder salt. Preferably the filler is selected from the group consisting of sodium sulphate, sodium chloride, calcium carbonate, magnesium carbonate, calcite, dolomite or mixtures thereof. The filler acts as a balancing ingredient and can be a neutral inorganic salt or mineral, preferably sodium sulphate or sodium chloride.

The aqueous slurry may optionally include a polymer. Suitable polymers include carboxylate polymers, soil release polymers, anti-redeposition polymers, cellulosic polymers, care polymers and any combination thereof. Preferably the polymer is a carboxylate polymer. The carboxylate polymer may be a homopolymer or a copolymer. Preferably the copolymer is a maleate/acrylate random copolymer. Preferably the maleate/acrylate random copolymer has a molecular weight ranging from 1000 Da to 100,000 Da, more preferably from 2000 Da to 100,000 Da, still preferably from 30,000 Da to 100,000 Da or from 50,000 Da to 100,000 Da, or from 60,000 Da to 80,000 Da. Preferably the homopolymer is a polyacrylate. Preferably the polyacrylate homopolymers has a molecular weight ranging from 4,000 Da to 9,000 Da. Preferably the aqueous slurry may include from 0 wt.% to 3 wt.% carboxylate polymer.

Step (iv): Spray drying the aqueous slurry to form a spray-dried detergent particle In the next step, the aqueous slurry is spray dried to form a spray-dried detergent particle.

The spray-drying is carried out using any of the conventional spray drying system known in the art. Preferably in the spray drying system the aqueous slurry is transferred through a pipe system to a pump system consisting of one or more pump and then further to a spray nozzle through which the slurry is released under pressure into a drying tower.

A typical spray-drying process involves the step of transferring the aqueous slurry through a pipe system leading to a first pump and then through a second pump and from a second pump to a plurality of spray nozzles. The first pump is typically a low- pressure pump, such as a pump that can generate a pressure of from 1x10⁵ Nov² to 1x10⁶ Nm^-2, which ensures proper flooding of the second pump. Typically, the second pump is a high-pressure pump, such as a pump can generate a pressure ranging from 2x10⁶ Nm^-2 to 2x10⁷ Nm^-2. Optionally, the aqueous slurry may be transferred through bolt catchers, magnetic filters, lump breakers, disintegrators such as the Ritz Mill, during the transfer of the aqueous slurry through the pipe system downstream the pump system/mixer in which the aqueous slurry is formed. The disintegrator is preferably positioned between the pumps. The flow rate of the aqueous slurry along the pipes is typically in the range from 800 Kg/hour to more than 50,000 Kg/hour.

Optionally, the spray drying system may include a deaeration system. The deaeration system is preferably a vacuum assisted de-aerator, which is preferably fed by a transfer pump. The deaeration system remove air bubbles formed during the slurry preparation, thus increasing the bulk density of the spray-dried detergent particle. Deaeration of the slurry may also be carried out by other mechanical means or chemical de-aeration means using antifoams or de-foamers.

Optionally, air injection system may be provided along the pipe system. The air injection system may be provided before or after the pump system. The air injection includes air flow and pressure controls, static mixer, pulsation dampener and compressor set which can aerate the slurry to get a lower bulk density for the spray dried particle. The gas injected into the slurry may be nitrogen, carbon dioxide, or simply atmospheric air introduced under a pressure higher than the pressure of the aqueous slurry maintained in the pipe system. A typical spray drying system can optionally include both the de-aeration system and air injection system to optimize the desired bulk density of the spray dried particle. Typical spray drying tower for detergent applications are counter-current spray drying tower. To obtain the desired moisture content and the particle size distribution the inlet hot air/hot steam temperature introduced into the spray drying tower is the range from 250°C to 500°C depending on the evaporation capacity and sizing of the tower. Preferably the tower exhaust air temperature can range from, 60°C to 200°C, more preferably 80°C to 200°C, still more preferably 80°C to 100°C depending on the loading of the tower. The aqueous slurry introduced into the spray nozzle of the spray drying tower is preferably at a temperature ranging from 60°C to 95°C. The spray drying tower may be a co-current spray drying tower, but these are less common. The spray-dried detergent particle existing the tower is maintained at a temperature less than 150°C, still preferably less than 100°C. The spray-drying is preferably conducted where the spray drying zone is under a negative pressure of at least 50 Nov², still preferably the negative pressure is from 50 Nov² to 600 Nm^-2. Preferably, the vacuum conditions is achieved by controlling the speed and/or dampener setting of the inlet and the outlet air fans.

Optionally, laundry ingredients in liquid form which cannot be added via slurry or tower may be sprayed onto the spray-dried detergent particle. The laundry ingredients in liquid form includes but is not limited to non-ionic surfactant, melted fatty acid or mixtures thereof. The spraying of the laundry ingredients in liquid form may be carried out while the spray-dried detergent particle passes through an inline low shear rotary drum, or an online densification kit which is typically a plough shear mixer.

The spray-dried detergent particle collected at the bottom of the tower may be subjected to cooling and conditioning by using an air lift or other similar process known to a person skilled in the art for cooling and conditioning spray-dried particle. The spray-dried particle collected from the bottom of the spray-drying tower is preferably mixed with a flow aid chosen from zeolite or similar fine mineral particles selected from the group consisting of silica, dolomite, precipitated calcite, light sodium carbonate, clay or mixtures thereof, just before being air-lifted. The zeolite may be of a synthetic origin. Preferably, the spray-dried detergent particle is subject to particle size classification to remove oversize material (> 2 mm typically) to provide a spray dried detergent particle which is free flowing. Preferably the fine material (< 100 microns typically) is elutriated with the exhaust air in the spray drying tower and captured and recycled back into the system via the dry cyclone, wet cyclone or bag filter system.

Spray-dried detergent particle:

According to an aspect of the present invention disclosed is a spray-dried particle obtainable by the process of the first aspect. Spray-dried particle formed from the process of the first aspect of the present invention preferably has a pH of 11.5 or less, preferably a pH ranging from 10.5 to 11.5 when measured using a 1 wt.% solution with distilled water at 25°C. After spray-drying, the collected spray-dried detergent particle at the base of the tower is preferably layered with a layering agent. Preferably the layering agent is selected from the group consisting of zeolite, silica, precipitated calcite, dolomite, sodium carbonate, salt or mixtures thereof. Preferably the level of the layering agent added to the spray-dried particle is from 0 wt.% to 10 wt.% of the surfactant content present in the spray-dried detergent particle. Preferably the layering agent is added to give additional anticaking benefit. This is also commonly referred to as base powder. This base powder may be used as a fully formulated laundry detergent composition or may be post dosed with other laundry ingredients to form a fully formulated laundry detergent composition.

Preferably the spray-dried detergent particle includes:

(i) 3 wt.% to 50 wt.% detersive surfactant;

(ii) 0.1 wt.% to 5 wt.% aluminium hydrate;

(iii) an alkaline builder selected from the group consisting of preferably from 8 wt.% to 17 wt.% alkali metal silicate, 5 wt.% to 20 wt.% alkali metal carbonate builder or mixtures thereof; and,

(iv) preferably from 9 wt.% to 70 wt.% filler;

(v) from 1 to 3.5 wt.% moisture.

Preferably the amount of detersive surfactant in the spray-dried detergent particle is not less than 3.5 wt.%, still preferably not less than 5 wt.%, more preferably not less than 8 wt.%, still more preferably not less than 10 wt.%, but typically not more than 34 wt.%, preferably not more than 33 wt.% or still preferably not more than 32 wt.%.

Preferably the amount of solubilized aluminium hydrate in the spray-dried detergent particle is not less than 0.2 wt.%, still preferably not less than 0.5 wt.%, more preferably not less than 0.8 wt.%, still more preferably not less than 1 wt.%, but typically not more than 4.5 wt.%, preferably not more than 3.5 wt.% or still preferably not more than 3 wt.%.

Preferably the amount of alkali metal silicate in the spray-dried detergent particle is not less than 10 wt.%, still preferably not less than 12 wt.%, more preferably not less than 13 wt.%, but typically not more than 16.5 wt.%, preferably not more than 15.5 wt.% or still preferably not more than 15 wt.%.

Preferably the amount of alkali metal carbonate in the spray-dried detergent particle is not less than 6 wt.%, still preferably not less than 8 wt.%, more preferably not less than 10 wt.%, but typically not more than 18 wt.%, preferably not more than 16 wt.% or still preferably not more than 15 wt.%.

Preferably the amount of moisture content in the spray-dried detergent particle is not less than 1.5 wt.%, still preferably not less than 1.8 wt.%, more preferably not less than 2 wt.%, but typically not more than 3 wt.%, preferably not more than 2.8 wt.% or still preferably not more than 2.75 wt.%.

Preferably the amount of filler in the spray-dried detergent particle is not less than 10 wt.%, still preferably not less than 15 wt.%, more preferably not less than 20 wt.%, but typically not more than 65 wt.%, preferably not more than 60 wt.% or still preferably not more than 55 wt.%.

It is preferred to keep the moisture content of the spray-dried detergent particle not more than 4.5 wt.% to ensure that the spray-dried particle is free-flowing and shows improved powder properties and extended shelf life. The spray dried detergent particle may preferably include from 0 wt.% to 4 wt.% polymer selected from antiredeposition polymer, soil release polymer, structuring polymer or mixtures thereof. Preferably the polymer is a polymeric carboxylate, preferably polyacrylate or a copolymer of acrylic acid and maleic acid. However other polymers may also be suitable such as polyamines (including the ethoxylated variants thereof), polyethylene glycol and polyesters. Polymeric soil suspending aids and polymeric soil release agents are particularly suitable. Preferably the spray dried detergent particle includes from 0 wt.% to 4 wt.% carboxylate polymer, still preferably from 0 wt.% to 2.5 wt.% carboxylate polymer, more preferably from 0 wt.% to 1 wt.% carboxylate polymer. The antiredeposition polymer may be a sodium carboxymethyl cellulose which may be used in an amount ranging from 0 wt.% to 4 wt.%.

Preferably the spray-dried detergent particle has a bulk density of less than 550g/L. Preferably the spray-dried detergent particle has a weight average particle size of from 300 micrometres to 600 micrometres.

The spray-dried detergent particle preferably comprises from 7 wt.% to 40 wt.% anionic surfactants, which is preferably a C to C20 linear alkyl benzene sulphonate, still C10 to C13 linear alkyl benzene sulphonate preferably and which is substantially neutralized with little or no acid residues. It is also preferred that the anionic surfactant is a combination of alkyl benzene sulphonate and either or both alkyl sulphate surfactant and alkyl ethoxylated sulphate.

The pH of the spray-dried particle when measured using a 1 wt.% solution with distilled water at room temperature ranges preferably from 10.5 to 11.5. The spray dried particle preferably has a lower alkalinity.

The spray-dried particle is typically post dosed with ingredients that are incompatible with the spray-drying process conditions to form a fully formulated laundry detergent composition. Typically, a fully formulated laundry detergent composition includes from 20 wt.% to 95 wt.% of the spray-dried particle according to the first aspect. The other laundry ingredients are post dosed by dry mixing the spray-dried particle with other laundry ingredients. These laundry ingredients and generally those that are not thermally stable. Non-limiting example of the other post dosed laundry ingredients includes enzymes, shading dye, fragrance, antifoams, cleaning polymers, care polymers, foam boosters, visual cues, chelating agents and mixtures thereof.

These components may be incompatible for many reasons including heat sensitivity, pH sensitivity or degradation in aqueous systems.

Laundry detergent composition

Detergent compositions of low to moderate bulk density may be prepared by spraydrying the aqueous slurry to form a spray-dried particle and optionally post-dosing (drymixing) further laundry ingredients. Alternately "compact" detergent compositions may be prepared by further mixing the spray dried particle prepared according to the present invention in a high-speed mixer/granulator, or other non-tower processes. The spray dried detergent particle may also be used for preparing a tablet composition by compacting powders, especially "concentrated" powders using the known tabletting process. Further, the spray dried detergent particle may be used for preparing a unit dose product where the spray-dried detergent particle is enclosed in a pouch, preferably a water-soluble pouch, more preferably a water-soluble pouch comprising a film forming polymer selected from polyvinyl alcohol, polyvinylpyrrolidone and other known film forming polymer.

The spray-dried particle mixed with layering agents is also known as base powder and is preferably formulated into a finished detergent composition by dry mixing heat sensitive ingredients into the base powder. In addition to heat sensitive ingredients some amount of alkalinity may be added back into the base powder by addition of alkaline ingredients, additionally other acidic or neutral may also be added to formulate the finished detergent composition.

The spray-dried detergent particle may be used as a fully formulated laundry detergent composition or may be additionally combined with other optional laundry ingredients to form a fully formulated laundry detergent composition. Non-limiting examples of the optional post-dosed laundry ingredients includes but is not limited to enzymes, antiredeposition polymers, perfumes, additional surfactant selected from amphoteric surfactant, zwitterionic surfactant, cationic surfactant and non-ionic surfactant, optical brighteners, antifoaming agent, foam boosters, fabric softeners such as smectite clays, amine softeners and cationic softeners; bleach and bleach activators; dyes or pigments, fillers, fluorescers, salts, soil release polymers, antiredeposition polymer dye transfer inhibitors. The antiredeposition polymer may be a sodium carboxymethyl cellulose which may be used in an amount ranging from 0 wt.% to 4 wt.%. These optional ingredients are well known to be used in a laundry detergent composition and added preferably by post-dosing.

The laundry detergent composition includes from 5 wt.% to 100 wt.% spray-dried detergent particle obtainable according to the first aspect of the present invention. More preferably from 30 wt.% to 95 wt.% of the spray-dried detergent particle obtainable according to the first aspect of the present invention.

Non-limiting examples of the post-dosed polymers include cleaning polymers, antiredeposition polymers, soil release polymers structuring polymers. Some examples include PET-PEOT polymer (Repel-o-Tex® SF2 ex.Solvay), copolymer of acrylic acid and maleic acid (Sokalan CP5 ex. BASF).

Fluorescers:

Suitable fluorescent brighteners include dis-styryl biphenyl compounds example Tinopal® CBS-X, di-amino stilbene di-sulfonic acid compounds, e.g. Tinopal® DMS pure Xtra and Blankophor® HRH, and Pyrazoline compounds, e.g. Blankophor® SN, and coumarin compounds, e.g. Tinopal® SWN. Preferred brighteners are: sodium 2 (4- styry)-3-sulfophenyl)-2H-napthol(1,2-d]triazole, disodium 4,4’bis{[4-anilino-6-(N methyl- N-2 hydroxyethyl)amino 1,3,5- triazin-2-yl)]amino]stilbene-2-2' disulfonate, disodium 4,4’bis([(4-anilino-6-morpholino-l,3,5-triazin-2-yl)]amino} stilbene-2-2'disulfonate, and disodium 4,4’- bis(2-sulfostyryl)biphenyl. A suitable fluorescent brightener is S C.l. Fluorescent Brightener 260, which may be used in its beta or alpha crystalline forms, or a mixture of these forms. Enzymes:

The composition of the present invention preferably includes an enzyme. It may preferably include one or more enzymes. Preferred examples of the enzymes include those which provide cleaning performance and/or fabric care benefits.

Examples of suitable enzymes include, but are not limited to, hemicellulases, peroxidases, proteases, cellulases, xylanases, lipases, xyloglucanase, phospholipases, esterases, cutinases, pectinases, mannanases, pectate lyases, keratinases, reductases, oxidases, phenoloxidases, lipoxygenases, ligninases, pullulanases, tannases, pentosanases, mannanases, G-glucanases, arabinosidases, hyaluronidase, chondroitinase, laccase, and amylases, or mixtures thereof. A typical combination is an enzyme combination that includes a protease and lipase in conjunction with one or more of amylase, mannanase and cellulase. When present in a detergent composition, the enzymes may be present at levels from about 0.00001% to about 2%, from about 0.0001% to about 1 % or from 0.001 % to about 0.5% enzyme protein by weight of the detergent composition.

Packaging and dosing

According to another aspect of the present invention, disclosed is a packaged article comprising a flexible container enclosing a laundry detergent composition having a spray dried detergent particle prepared according to the first aspect of the present invention. The flexible container is preferably made from a packaging material suitable for packaging laundry detergent composition and but not limited to polyolefin film, laminates, paper based films or laminates, multilayered structures include two or more flexible structures and other materials known to a person skilled in the art. Typically the flexible container includes polyethylene films having polymer selected from HDPE, LLDPE, mLLDPE, LDPE or combination thereof. The flexible films may be made of monomaterial or combination of different materials. Preferably the flexible packaging container is a flexible pouch or a bag. It is preferably selected from a material which is biodegradable, compostable, recyclable or combinations of those. The flexible container may preferably include a measurement means which may be supplied with the package either as a part of the closure of the container or as an integrated system or a separate dosing measure may be provided along with the package.

In yet another embodiment the laundry detergent composition comprising the spray dried detergent particle of the present invention may be packaged as unit dose product enclosed within a polymeric film, wherein the polymeric film is water soluble or disintegrates upon addition to the wash water. Alternatively, the spray-dried detergent particle or a laundry detergent composition including the spray-dried particle of the invention may be supplied in multidose plastics packs with a top or bottom closure, may be enclosed in a flexible container.

The packaging material suitable for packaging may include but not limited to multilayer polyethylene film, laminate, paper based, and other materials known to a person skilled in the art. Preferably the packaging material is selected from material which are biodegradable or recyclable.

According to another aspect of the present invention, provided is a method of laundering fabric using a spray dried detergent particle or a laundry composition comprising a spray dried detergent particle according to the present invention which involves the step of diluting the dose of detergent composition with water to obtain a wash liquor and washing fabrics with the wash liquor so formed. In automatic washing machines the dose of detergent composition is typically put into a dispenser and from there it is flushed into the machine by the water flowing into the machine, thereby forming the wash liquor. From 5 up to about 65 litres of water may be used to form the wash liquor depending on the machine configuration. The dose of detergent composition may be adjusted accordingly to give appropriate wash liquor concentrations. The dilution step preferably provides a wash liquor which comprises inter alia from about 3 to about 20 g/wash of detersive surfactants (as are further defined above). Examples

Example 1 : Preparing an aqueous slurry and a spray dried particle according to the present invention A spray-dried laundry detergent composition according to the present invention was prepared by first mixing water, neutralizing agent (NaOH, 50% aqueous solution) to form an aqueous mixture to which aluminium hydrate is added and solubilized. Thereafter other ingredients are added in the order as shown in table 1. The composition of the ingredients added to the form a batch of 950 Kg aqueous slurry is provided in Table 1.

Table 1

Preparing the spray-dried detergent particle: The aqueous slurry of Ex 1 was spray dried to prepare a spray dried detergent and the spray-dried particle was thereafter evaluated.

Next the above aqueous detergent slurry was spray dried in a counter-current spray drying tower. The aqueous detergent slurry was heated to 80°C and pumped under pressure (7.5x106 Nm-²), into a counter current spray-drying tower with an air inlet temperature ranging from between 250°C to 330°C. The inlet fan was set to provide a tower inlet airflow of 187,500 kgtr¹. The exhaust fan was controlled to create a negative pressure in the tower of -200 Nm^-2 (typically the outlet air flow rate through the exhaust fan is between 220,000 kgh'¹ to 240,000 kgtr¹, this includes the evaporated water from the slurry). The aqueous slurry was atomised into the tower where the atomised slurry was dried to produce a spray-dried detergent particle, which was then cooled and sieved to remove oversize material (> 1.8mm). The spray dried detergent particle obtained was found to be free-flowing. Fine material (<0.175mm) was elutriated along with the exhaust air coming out of the spray-drying tower and was later collected in a post tower containment system. The spray-dried detergent particle had a moisture content of 2.0 wt.%, a bulk density of 350g/L and a particle size distribution such that greater than 90 wt.% of the spray-dried detergent particle has a particle size ranging from 175 to 710 micrometres. The temperature of the spray-dried detergent particle exiting the tower has a temperature of below 150°C. The composition of the spray- dried detergent particle obtained by spray-drying the aqueous detergent slurry is given below. The composition of the spray dried powder is provided in Table 2 below.

Table 2

The spray dried particle has good powder properties and was free-flowing due to the presence of solubilized aluminium hydrate even when the sodium silicate and sodium carbonate levels were kept to minimum. The spray-dried particle had lower alkalinity and was found to be good for hand washing fabric.

Example 2: Evaluation of caking tendency of the spray-dried particle

700 grams of the spray dried detergent particle according to the present invention was packed into a laminate with water vapour transmission rate of less than 5 gram/m²/day and stored at storage condition of 45°C and 80 RH for a period of 12 weeks. Thereafter the spray-dried particle was evaluated for wt.% of caking. This was performed by segregating the caked particle and measuring their weight and thereafter the wt% of spray dried particle that had caked was calculated and noted. The % caking value are provided in table 3 below.

Similarly, a control spray-dried particle with the formulation as provided in table 3 was prepared under similar spraying conditions as the inventive Ex 1 was then similarly stored. The % caking was measured after 12 week and the values were noted and provided in table 3 below.

Table 3

The above table 3 shows that the spray-dried detergent particle according to the present invention (Ex 1) shows good powder properties even after 12 weeks and is comparative less prone to caking than the control composition.

Claims

28 Claims

1. A process for preparing a spray-dried laundry detergent particle, said process comprising the steps of:

(i) solubilizing aluminium hydrate in an aqueous mixture by mixing aluminium hydrate with an alkaline source wherein the pH of the aqueous mixture ranges from 12 to 14;

(ii) adding an alkaline builder selected from (i) alkali metal carbonate salt (ii) alkali metal silicate salt or mixtures thereof to form an aqueous slurry; wherein the aqueous slurry comprises a solubilized aluminium hydrate, detersive surfactant, and the alkaline builder wherein the alkali builder comprises from 3 wt.% to 15 wt.% alkali metal carbonate builder and wherein the aqueous slurry has a pH ranging from 10 to 12;

(iii) spray-drying the aqueous slurry to form said spray dried laundry detergent particle.

2. A process according to claim 1 wherein the aluminium hydrate is in-situ formed or preformed.

3. A process according to claim 2 wherein the aluminium hydrate is formed in-situ by reacting an aluminium salt with a strong base selected from the group consisting of alkali metal hydroxide, alkaline earth metal hydroxide or mixtures thereof.

4. A process according to claim 3 wherein the aluminium salt is an aluminium sulphate, preferably wherein the aluminium sulphate is reacted with a strong base to form in-situ aluminium hydrate.

5. A process according to claim 2 wherein the aluminium hydrate is formed in-situ by reacting an alkali metal aluminate salt with an inorganic acid to form in-situ aluminium hydrate. A process according to claim 5 wherein the aluminium hydrate is formed in-situ by reacting alkaline sodium aluminate with alkyl benzene sulphonic acid to form in-situ aluminium hydrate. A process according to any one of the preceding claims wherein a detersive surfactant is added to the aqueous mixture before or after the solubilization of the aluminium hydrate. A process according to any one of the preceding claims wherein the alkaline source in step (i) is selected from the group consisting of alkali metal hydroxide, alkali metal silicate or mixtures thereof. A process according to any one of the preceding claims wherein the aqueous slurry comprises a filler selected from the group consisting of sodium sulphate, sodium chloride, calcium carbonate, dolomite, calcite or mixtures thereof. A process according to any one of the preceding claims wherein the aqueous slurry comprises less than 3 wt.% phosphate builder/salt, still preferably less than 1 wt.% phosphate builder/salt. A process according to any one of the preceding claims wherein the aqueous slurry comprises a carboxylate polymer. A process according to any one of the preceding claims wherein the detersive surfactant is an anionic surfactant, preferably selected from the group consisting of alkyl benzene sulfonate, alkoxylated alkyl sulphate, alkyl sulphate, alkoxylated alcohol; and mixtures thereof. A process according to any one of the preceding claims, wherein the aqueous slurry comprises:

(i) 2 wt.% to 35 wt.% detersive surfactant;

(ii) from 0.06 wt.% to 4 wt.% solubilized aluminium hydrate; (iii) an alkaline builder selected from the group consisting of from 4 wt.% to 15 wt.% alkali metal silicate salt, from 3 wt.% to 15 wt.% alkali metal carbonate builder or mixtures thereof;

(iv) preferably from 7 wt.% to 56 wt.% filler selected from sodium sulphate, sodium chloride, calcium carbonate, magnesium carbonate or mixtures thereof;

(v) from 25 wt.% to 40 wt.% water. A process according to any one of the preceding claims, wherein the spray-dried detergent particle obtained according to any one of the preceding claims, comprises:

(i) 3 wt.% to 50 wt.% detersive surfactant;

(ii) 0.1 wt.% to 5 wt.% solubilized aluminium hydrate;

(iii) an alkaline builder selected from the group consisting of from 8 to 17 wt.% alkali metal silicate salt, from 5 wt.% to 20 wt.% alkali metal carbonate builder or mixtures thereof;

(iv) preferably from 1 wt.% to 3 wt.% water; and,

(v) preferably from 9 wt.% to 70 wt.% filler selected from sodium sulphate, sodium chloride, calcium carbonate, magnesium carbonate or mixtures thereof. A laundry detergent composition comprising from 5 wt.% to 100 wt.% of the spray dried detergent particle according to any one of the preceding claims.