Classifications

• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/02—Inorganic compounds ; Elemental compounds
  • C11D3/04—Water-soluble compounds
  • C11D3/046—Salts
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D11/00—Special methods for preparing compositions containing mixtures of detergents
  • C11D11/02—Preparation in the form of powder by spray drying
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D17/00—Detergent materials or soaps characterised by their shape or physical properties
  • C11D17/06—Powder; Flakes; Free-flowing mixtures; Sheets
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/02—Inorganic compounds ; Elemental compounds
  • C11D3/04—Water-soluble compounds
  • C11D3/10—Carbonates ; Bicarbonates
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/16—Organic compounds
  • C11D3/37—Polymers
  • C11D3/3746—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C11D3/3753—Polyvinylalcohol; Ethers or esters thereof
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/16—Organic compounds
  • C11D3/37—Polymers
  • C11D3/3746—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C11D3/3757—(Co)polymerised carboxylic acids, -anhydrides, -esters in solid and liquid compositions
  • C11D3/3761—(Co)polymerised carboxylic acids, -anhydrides, -esters in solid and liquid compositions in solid compositions
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D2111/00—Cleaning compositions characterised by the objects to be cleaned; Cleaning compositions characterised by non-standard cleaning or washing processes
  • C11D2111/40—Specific cleaning or washing processes
  • C11D2111/44—Multi-step processes

Definitions

• the present invention relates to a spray-dried detergent powder and a process for making a spray-dried detergent powder.
• Particulate detergent compositions comprise detersive active ingredients. Often-times these detersive ingredients make the particles 'sticky'. This has the effect of making the particles stick together which negatively impacts the flowability of the granular composition and can affect the dissolution in the wash liquor. Therefore, a 'bulking agent' in the form of a separate particle or powder is often added to the granular composition to counteract the stickiness and maintain good flowability.
• Bulking agents include, sulphates, carbonates, silicates, clays (such as bentonite clay), and zeolite.
• carbonates and silicates affect the pH of the wash liquor, making it alkaline and so affecting the cleaning performance of the detergent components.
• Zeolite is a detergent builder and so interacts with ions in the water that are the source of water hardness, thus it forms residues of these complexes that deposit on fabrics. Clays result in fabric greying, fabric colour fading and residue deposition on the fabrics.
• the most preferred bulking agent is sulphate, as this is pH neutral, and does not act as a builder.
• natural sulphate has a high bulk density so upon addition to water it rapidly sinks and forms a sediment at the bottom of the container. Consumers associate this sedimentation with 'poor cleaning' as they believe that the composition is not dissolving into the water and so 'not working'.
• the slowly dissolving sediment makes the wash liquor feel 'gritty'. Consumers associate this with 'dirty wash water' and 'lack of cleaning'.
• the sulphate sediments in the wash liquor it can trap other detergent components and so affect the overall cleaning performance.
• a spray-dried powder comprising (i) from 20 to 80wt% of a first spray-dried particle comprising between 5wt% and less than 45wt% sulphate, anionic detersive surfactant, and having a bulk density of from 120g/l to 450g/l: and (ii) from 20 to 80wt% of a second spray-dried particle comprising at least 45wt% sulphate, and having a bulk density of from 350g/l to 700g/l overcame this issue. It was further surprisingly found that providing the sulphate in a second particle according to the present invention improved the ability to formulate the sulphate into the spray-dried powder during manufacture.
• a first aspect of the present invention is a spray-dried powder comprising (i) from 20 to 80wt% of a first spray-dried particle comprising between 5wt% and less than 45wt% sulphate, anionic detersive surfactant, and having a bulk density of from 120g/l to 450g/l: and (ii) from 20 to 80wt% of a second spray-dried particle comprising at least 45wt% sulphate and having a bulk density of from 350g/l to 700g/l.
• a second aspect of the present invention is a process for making the spray-dried powder according to the first aspect.
• the spray dried powder of the present invention comprises (i) from 20 to 80wt% of a first spray-dried particle comprising between 5wt% and less than 45wt% sulphate, anionic detersive surfactant, and having a bulk density of from 120g/l to 450g/l: and (ii) from 20 to 80wt% of a second spray-dried particle comprising at least 45wt% sulphate, and having a bulk density of from 350g/l to 700g/l.
• the first particle can comprise from 50wt% to 80wt%, or even from 60wt% to 80wt% by weight of the spray-dried powder. Alternatively, the first particle can comprise from 20wt% to 50wt% by weight of the spray-dried powder.
• the second particle can comprise from 50wt% to 80wt%, or even from 60wt% to 80wt% by weight of the spray-dried powder. Alternatively, the second particle can comprise from 20wt% to 50wt% by weight of the spray-dried powder.
• the spray-dried detergent powder is suitable for any detergent application, for example: laundry, including automatic washing machine laundering and hand laundering, and even bleach and laundry additives; hard surface cleaning; dish washing, especially automatic dish washing; carpet cleaning and freshening.
• the spray-dried detergent powder is a spray-dried laundry detergent powder.
• the spray-dried detergent powder can be a fully formulated detergent product, such as a fully formulated laundry detergent product, or it can be combined with other particles to form a fully formulated detergent product, such as a fully formulated laundry detergent product.
• the spray-dried laundry detergent particles may be combined with other particles such as: enzyme particles; perfume particles including agglomerates or extrudates of perfume microcapsules, and perfume encapsulates such as starch encapsulated perfume accord particles; surfactant particles, such as non-ionic detersive surfactant particles including agglomerates or extrudates, anionic detersive surfactant particles including agglomerates and extrudates, and cationic detersive surfactant particles including agglomerates and extrudates; polymer particles including soil release polymer particles, cellulosic polymer particles; buffer particles including carbonate salt and/or silicate salt particles, preferably a particle comprising carbonate salt and silicate salt such as a sodium carbonate and sodium silicate co-particle,
• the spray-dried detergent powder may also be especially preferred for the spray-dried detergent powder to comprise low levels, or even be essentially free, of builder. By essentially free of it is typically meant herein to mean: “comprises no deliberately added”. In a preferred embodiment, the spray-dried detergent powder comprises no builder.
• the spray-dried particle is typically flowable, typically having a cake strength of from 0 N to 20 N, preferably from 0 N to 15 N, more preferably from 0 N to 10 N, most preferably from 0 N to 5 N.
• the method to determine the cake strength is described in more detail elsewhere in the description.
• the spray-dried detergent powder comprises a first spray-dried particle and a second spray-dried particle.
• first and second spray-dried particles we herein mean that the spray-dried detergent powder comprises two distinct particle types, the first spray-dried particle being formed independently of the second spray-dried particle.
• the first spray-dried particle has a different intra-particulate chemistry to that of the second spray-dried particle.
• the spray-dried powder comprising the first and second spray-dried particles typically comprises from 0wt% to 7wt%, preferably from 0.5wt% to 5wt%, and preferably from 1wt% to 2wt% water.
• the first spray-dried particle comprises between 5wt% and less than 45wt% sulphate, anionic detersive surfactant, and has a bulk density of from 120g/l to 450g/l.
• the first spray-dried particle may comprise between 5wt% and 40wt%, or even between 10wt% and 30wt%, or even between 10wt% and 25wt%, or even between 15wt% and 25wt% sulphate. Sulphate suitable for use in the present invention is described in more detail below.
• the first spray-dried particle may comprise 0 to 5wt%, preferably 1 to 5wt% polymer, preferably 1.5 to 3wt% polymer.
• the polymer in the first particle can be selected from a polycarboxylate homopolymer or a polycarboxylate copolymer, preferably the polymer is selected from polyacrylate homopolymer or acrylic acid/maleic acid copolymer. Suitable polymers are described in more detail below.
• the first particle may comprise at least 5wt%, or at least 10wt%, or at least 15wt%, or at least 30wt% anionic detersive surfactant.
• the first particle may comprise at most 50wt%, or at most 40wt%, or at most 30wt%, or at most 20wt% anionic detersive surfactant.
• Suitable anionic detersive surfactants are described in more detail below.
• the anionic detersive surfactant can be alkyl benzene sulphonic acid or salt thereof, alkyl ethoxylated sulphate, or a mixture thereof.
• the anionic detersive surfactant can be a mixture of alkyl benzene sulphonic acid or salt thereof and alkyl ethoxylated sulphate.
• the first particle may comprise from 0 to 20wt% silicate, or between 1 and 15wt% silicate.
• the first particle may comprise from 0 to 50wt% carbonate, or between 10 and 40wt% carbonate, or between 15 and 40wt% carbonate.
• lower carbonate levels result in lower pH of the wash liquor.
• a wash liquor with a lower pH is less harsh on the skin and so provides a skin mildness benefit for hand washing of fabrics.
• the first particle may comprise less than 15wt% of an alkali metal chloride.
• the first particle may comprise from 0.5wt% to 12wt% alkali metal chloride, or from 1wt% to 10wt% alkali metal chloride.
• the alkali metal chloride may be sodium chloride, potassium chloride or a mixture thereof.
• the first particle may comprise sodium hydroxide.
• the first particle may comprise between 0.1wt% and 5wt%, or even between 0.25wt% and 5wt% or even between 0.5wt% and 5wt%, or even between 0.5wt% and 3.5wt% sodium hydroxide.
• the first particle may comprise HEDP, brighteners or a mixture thereof. Brighteners are described in more detail below.
• the first particle may comprise a hydrotrope.
• Hydrotropes are compounds that aid in the solubilisation of compounds in aqueous solutions.
• the hydrotrope is present at in the first particle at a ratio of hydrotrope to anionic detersive surfactant of between 1:10 to 1:20. Suitable hydrotropes are described in more detail below.
• the first particle may have a mean particle size of between 350 and 500 ⁇ m, preferably between 375 and 425 ⁇ m.
• the first spray-dried particle may have a bulk density of from 120g/l to 300g/l or from 300g/l to 450g/l.
• the second spray-dried particle comprises at least 45wt% sulphate and has a bulk density of from 350g/l to 700g/l.
• the second particle may comprise at least 55wt%, or even 65wt% or even 75wt% sulphate.
• the second particle may comprise at most 99wt% sulphate, or even 90wt%, or even 85wt% or even 80wt% sulphate.
• the second particle may comprise carbonate. If carbonate is present in the second particle, it may be present at a concentration of between 0wt% and 30wt%, or at most 20wt%, or even at most 10wt%. Carbonate may be present in the second particle at a concentration of at least 1wt%, or even 2wt%, or even 5wt% or even 10wt%, or even 15wt%.
• the second particle may comprise polymer, preferably from 0 to 10wt% polymer, or even 1wt% to 8wt% polymer. Suitable polymers are described in more detail below.
• the polymer in the second particle can be selected from a polycarboxylate homopolymer or a polycarboxylate copolymer, preferably the polymer is selected from polyacrylate homopolymer or acrylic acid/maleic acid copolymer.
• the second particle may comprise from 0 to 15wt%, or even from 1 to 12wt%, or from 2 to 10wt% anionic detersive surfactant. Suitable anionic detersive surfactants are described in more detail below.
• the anionic detersive surfactant in the second particle can be linear alkylbenzene sulfonate. Or the anionic detersive surfactant in the second particle can be alkyl ethoxylated sulphate
• the second particle may comprise from 0 to 10wt% silicate, or even between 1 and 10wt% silicate.
• the second particle may comprise sodium hydroxide.
• the second particle may comprise between 0.1wt% and 5wt%, or even between 0.25wt% and 5wt% or even between 0.5wt% and 5wt%, or even between 0.5wt% and 3.5wt% sodium hydroxide.
• the presence of sodium hydroxide results in a more clear wash liquor when the second particle is dissolved in the wash liquor. Consumers prefer clear wash liquors as they perceive this to mean that the wash liquor is 'not dirty' and so providing improved fabric cleaning.
• the second particle may have a mean particle size of between 350 and 500 ⁇ m, preferably between 375 and 425 ⁇ m.
• the density of the second particle means that it floats in the wash liquor and exhibits reduced sedimentation.
• the density of the second particle is lower than traditionally used sulphate particles. This is achieved by injecting air into an aqueous slurry which is then spray-dried to produce the second particle. This results in 'air bubbles' in the particle.
• This increased porosity means that the particle has a higher surface area, and so the particle dissolves faster in the wash liquor.
• This faster dissolution and lower level of sedimentation means that the wash liquor does not have the same gritty feel as if traditional sulphate particles were used.
• the sulphate (second) particle still acts a bulking agent ensuring excellent flowability of the powder composition.
• the bulk density of the second particle can be from 350g/l to 600g/l, or from 400g/l to 550g/l.
• the sulphate in the first spray-dried particle and independently in the second spray-dried particle can be any suitable sulphate. It may be sodium sulphate.
• Carbonate can be any suitable carbonate, for example sodium or potassium carbonate, burkeite, sesquicarbonate or crystal modified carbonate such as crystal modified burkeite.
• the polymer in the first particle and independently in the second particle can be any suitable polymer.
• the anionic detersive surfactant can be alkyl benzene sulphonic acid or salt thereof, alkyl ethoxylated sulphate, or a mixture thereof.
• the anionic detersive surfactant is a mixture of alkyl benzene sulphonic acid or salt thereof and alkyl ethoxylated sulphate.
• Suitable polymers include carboxylate polymers, such as polyacrylates, and acrylate/maleate co-polymers and other functionalized polymers such as styrene acrylates.
• carboxylate polymer is an acrylate/maleate copolymer having an average molecular weight of about 2,000 to about 100,000 and a ratio of acrylate to maleate segments of from about 30:1 1 to about 1:1.
• AGP amphiphilic graft polymer
• Suitable AGPs are obtainable by grafting a polyalkylene oxide of number average molecular weight from about 2,000 to about 100,000 with vinyl acetate, which may be partially saponified, in a weight ratio of polyalkylene oxide to vinyl acetate of about 1:0.2 to about 1:10.
• the vinyl acetate may, for example, be saponified to an extent of up to 15%.
• the polyalkylene oxide may contain units of ethylene oxide, propylene oxide and/or butylene oxide. Selected embodiments comprise ethylene oxide.
• the polyalkylene oxide has a number average molecular weight of from about 4,000 to about 50,000, and the weight ratio of polyalkylene oxide to vinyl acetate is from about 1:0.5 to about 1:6.
• a material within this definition based on polyethylene oxide of molecular weight 6,000 (equivalent to 136 ethylene oxide units), containing approximately 3 parts by weight of vinyl acetate units per 1 part by weight of polyethylene oxide, and having itself a molecular weight of about 24,000, is commercially available from BASF as Sokalan HP22.
• Suitable AGPs may be present in the detergent composition at weight percentages of from about 0 to about 5%, preferably from about above 0% to about 4%, or from about 0.5% to about 2%. In some embodiments, the AGP is present at greater than about 1.5wt%. The AGPs are found to provide excellent hydrophobic soil suspension even in the presence of cationic coacervating polymers.
• Preferred AGPs are based on water-soluble polyalkylene oxides as a graft base and side chains formed by polymerization of a vinyl ester component. These polymers having an average of less than or equal to one graft site per 50 alkylene oxide units and mean molar masses (Mw) of from about 3000 to about 100,000.
• Another suitable polymer is polyethylene oxide, preferably substituted or un-substituted.
• Another suitable polymer is cellulosic polymer, preferably selected from alkyl cellulose, alkyl alkoxyalkyl cellulose, carboxylalkyl cellulose, alkyl carboxyalkyl, more preferably selected from carboxymethyl cellulose (CMC) including blocky CMC, methyl cellulose, methyl hydroxyethyl cellulose, methyl carboxymethyl cellulose, and mixures thereof.
• CMC carboxymethyl cellulose
• suitable polymers are soil release polymers. Suitable polymers include polyester soil release polymers. Other suitable polymers include terephthalate polymers, polyurethanes, and mixtures thereof. The soil release polymers, such as terephthalate and polyurethane polymers can be hydrophobically modified, for example to give additional benefits such as sudsing.
• polystyrene resin preferably polyethylene imine polymers, preferably having ethylene oxide and/or propylene oxide functionalized blocks
• suitable polymers include synthetic amino containing amphoteric/and/or zwitterionic polymers, such as those derived from hexamethylene diamine.
• Another suitable polymer is a polymer that can be co-micellized by surfactants, such as the AGP described in more detail above.
• Suitable polymers include silicone, including amino-functionalised silicone.
• Suitable polymers can include clay and soil removal/anti-redeposition agents being co-polymers comprising:
• Suitable polymers include polysaccharide polymers such as celluloses, starches, lignins, hemicellulose, and mixtures thereof.
• Suitable polymers include cationic polymers, such as deposition aid polymers, such as cationically modified cellulose such as cationic hydroxy ethylene cellulose, cationic guar gum, cationic starch, cationic acrylamides and mixtures thereof.
• deposition aid polymers such as cationically modified cellulose such as cationic hydroxy ethylene cellulose, cationic guar gum, cationic starch, cationic acrylamides and mixtures thereof.
• Suitable anionic detersive surfactants include sulphate and sulphonate detersive surfactants.
• Preferred sulphonate detersive surfactants include alkyl benzene sulphonate, preferably C 10-13 alkyl benzene sulphonate.
• Suitable alkyl benzene sulphonate (LAS) is obtainable, preferably obtained, by sulphonating commercially available linear alkyl benzene (LAB);
• suitable LAB includes low 2-phenyl LAB, such as those supplied by Sasol under the tradename Isochem® or those supplied by Petresa under the tradename Petrelab®, other suitable LAB include high 2-phenyl LAB, such as those supplied by Sasol under the tradename Hyblene®.
• a suitable anionic detersive surfactant is alkyl benzene sulphonate that is obtained by DETAL catalyzed process, although other synthesis routes, such as HF, may also be suitable.
• Preferred sulphate detersive surfactants include alkyl sulphate, preferably C 8-18 alkyl sulphate, or predominantly C 12 alkyl sulphate.
• alkyl alkoxylated sulphate preferably alkyl ethoxylated sulphate, preferably a C 8-18 alkyl alkoxylated sulphate, preferably a C 8-18 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 C 8-18 alkyl ethoxylated sulphate having an average degree of ethoxylation of from 0.5 to 10, preferably from 0.5 to 7, more preferably from 0.5 to 5 and most preferably from 0.5 to 3.
• alkyl sulphate, alkyl alkoxylated sulphate and alkyl benzene sulphonates may be linear or branched, substituted or un-substituted.
• Suitable brighteners are stilbenes, such as brightener 15.
• Other suitable brighteners are hydrophobic brighteners, and brightener 49.
• the brightener may be in micronized particulate form, having a weight average particle size in the range of from 3 to 30 micrometers, or from 3 micrometers to 20 micrometers, or from 3 to 10 micrometers.
• the brightener can be alpha or beta crystalline form.
• the detergent composition preferably comprises C.I. fluorescent brightener 260 in alpha-crystalline form having the following structure:
• the C.I. fluorescent brightener 260 is preferably predominantly in alpha-crystalline form. Predominantly in alpha-crystalline form means that preferably at least 50wt%, or at least 75wt%, or even at least 90wt%, or at least 99wt%, or even substantially all, of the C.I. fluorescent brightener 260 is in alpha-crystalline form.
• the brightener is typically in micronized particulate form, having a weight average primary particle size of from 3 to 30 micrometers, preferably from 3 micrometers to 20 micrometers, and most preferably from 3 to 10 micrometers.
• the detergent composition may comprises C.I. fluorescent brightener 260 in beta-crystalline form, and preferably the weight ratio of: (i) C.I. fluorescent brightener 260 in alpha-crystalline form, to (ii) C.I. fluorescent brightener 260 in beta-crystalline form is at least 0.1, preferably at least 0.6.
• BE680847 relates to a process for making C.I fluorescent brightener 260 in alpha-crystalline form.
• the hydrotrope typically has at least one sulphonate group such as found in an alkyl aryl sulphonate or an alkyl aryl sulfonic acid.
• the alkyl aryl sulphonate includes: sodium, potassium, calcium and ammonium xylene sulphonates, sodium, potassium, calcium and ammonium toluene sulphonates; sodium, potassium, calcium and ammonium cumene sulphonates; sodium, potassium, calcium and ammonium substituted or unsubstituted naphthalene sulphonates; and a mixture thereof.
• the alkyl aryl sulfonic acid includes: xylene sulfonic acid, toluene sulfonic acid, cumene sulfonic acid, substituted or unsubstituted naphthalene sulfonic acid and a mixture thereof.
• the hydrotrope is selected from the sodium and potassium salts of cumene sulphonate and toluene sulphonate and a mixture thereof.
• the salts of p-toluene sulfonate may also be used herein.
• the present invention has found that by adding a hydrotrope, the slurry can be thickened so as to improve structuring and increase the retention of gas in the slurry.
• the amount of hydrotrope needs to be cost-effective in the formulation.
• Such hydrotropes are readily available as commodity items from multiple sources around the world.
• the hydrotrope has multiple sulphonate groups, such as found in the DOWFAX(TM) series of hydrotropes available from The Dow Chemical Company, Midland Michigan, USA.
• the hydrotrope has two sulphonate groups on a diphenyl oxide backbone, while the hydrophobic portion may be a linear or branched alkyl group of from six to sixteen carbon atoms.
• a preferred hydrotrope is alkyldiphenyloxide disulphonate, monoalkoxylated, which is commercially available from the Dow Chemical Company, Midland Michigan, USA as DOWFAX XD.
• Suitable zeolite builder includes include zeolite A, zeolite P and zeolite MAP. Especially suitable is zeolite 4A.
• a typical phosphate builder is sodium tri-polyphosphate.
• a suitable silicate salt is sodium silicate, preferably 1.6R and/or 2.0R sodium silicate.
• the composition typically comprises other detergent ingredients.
• Suitable detergent ingredients include: transition metal catalysts; imine bleach boosters; enzymes such as amylases, carbohydrases, cellulases, laccases, lipases, bleaching enzymes such as oxidases and peroxidases, proteases, pectate lyases and mannanases; source of peroxygen such as percarbonate salts and/or perborate salts, preferred is sodium percarbonate, the source of peroxygen is preferably at least partially coated, preferably completely coated, by a coating ingredient such as a carbonate salt, a sulphate salt, a silicate salt, borosilicate, or mixtures, including mixed salts, thereof; bleach activator such as tetraacetyl ethylene diamine, oxybenzene sulphonate bleach activators such as nonanoyl oxybenzene sulphonate, caprolactam bleach activators, imide bleach activators such as N-nonanoyl-N
• a smooth plastic cylinder of internal diameter 6.35 cm and length 15.9 cm is supported on a suitable base plate.
• a 0.65 cm hole is drilled through the cylinder with the centre of the hole being 9.2cm from the end opposite the base plate.
• a metal pin is inserted through the hole and a smooth plastic sleeve of internal diameter 6.35cm and length 15.25 cm is placed around the inner cylinder such that the sleeve can move freely up and down the cylinder and comes to rest on the metal pin.
• the space inside the sleeve is then filled (without tapping or excessive vibration) with the spray-dried powder such that the spray-dried powder is level with the top of the sleeve.
• a lid is placed on top of the sleeve and a 5 kg weight placed on the lid. The pin is then pulled out and the spray-dried powder is allowed to compact for 2 minutes. After 2 minutes the weight is removed, the sleeve is lowered to expose the powder cake with the lid remaining on top of the powder.
• a metal probe is then lowered at 54 cm/min such that it contacts the centre of the lid and breaks the cake.
• the maximum force required to break the cake is recorded and is the result of the test.
• a cake strength of 0 N refers to the situation where no cake is formed.
• the process for making the spray-dried powder of the present invention comprises the steps of;
• Step (a): the first aqueous slurry can be formed by mixing in any suitable vessel, such as a mixer, in the standard manner.
• suitable mixers include vertical mixers, slurry mixers, tank agitators, crutcher mixers and the like.
• the first aqueous slurry may comprise silicate, polymer, sulphate, carbonate, sodium hydroxide or a mixture thereof.
• the anionic detersive surfactant is LAS.
• the LAS maybe added to the mixing vessel in the neutralized form or may be added in the acid form (linear alkylbenzene sulphonic acid, HLAS). If added as HLAS, neutralization is effected upon contact to a suitable alkaline source in the mixer vessel (in-situ or dry neutralization).
• HLAS linear alkylbenzene sulphonic acid
• neutralization is effected upon contact to a suitable alkaline source in the mixer vessel (in-situ or dry neutralization).
• LAS is a highly viscous material.
• water is often added to lower the viscosity.
• Hydrotropes can be added to the LAS and water mix which help lower the viscosity and so reduce the amount of water needed. However, it was surprisingly found that the addition of a hydrotrope to the HLAS acts to lower the viscosity even further, so even less water is needed to achieve a suitable viscosity.
• the anionic detersive surfactant comprises a hydrotrope.
• the ratio of hydrotrope to anionic detersive surfactant in the slurry is between 1:10 and 1:20.
• a hydrotrope is added to HLAS, preferably at a ratio of hydrotrope to HLAS of between 1:10 and 1:20. The HLAS and hydrotrope mix is then either neutralized prior to addition to the mixer or is neutralized in-situ in the mixer.
• Step (b): the second aqueous slurry can be formed by mixing in any suitable vessel, such as a mixer, in the standard manner.
• suitable mixers include vertical mixers, slurry mixers, tank agitators, crutcher mixers and the like.
• the second aqueous slurry may comprise silicate, polymer, anionic detersive surfactant, sodium hydroxide or a mixture thereof.
• the first aqueous slurry is transferred in a pipe.
• the first aqueous slurry is typically transferred though an intermediate storage vessel such as a drop tank, for example when the process is semi-continuous.
• the process can be a continuous process, in which case no intermediate storage vessel is required.
• the first aqueous slurry is transferred through at least one pump, preferably at least two, or even at least three or more pumps, although one or two, preferably two pumps may be preferred.
• the first pump is a low pressure pump, such as a pump that is capable of generating a pressure of from 3x10 5 to 1x10 6 Pa
• the second pump is a high pressure pump, such as a pump that is capable of generating a pressure of from 2x10 6 to 1x10 7 Pa.
• the first aqueous slurry is transferred through a disintegrator, such as disintegrators supplied by Hosakawa Micron.
• the disintegrator can be positioned before the pump, or after the pump. If two or more pumps are present, then the disintegrator can also be positioned between the pumps.
• the pumps, disintegrators, intermediate storage vessels, if present are all in series configuration. However, some equipment may be in a parallel configuration.
• a suitable spray nozzle is a Spray Systems T4 Nozzle.
• the first aqueous slurry may be made by firstly mixing water and if present, silicate, polymer, carbonate, sulphate, sodium hydroxide or a mixture thereof. This first aqueous slurry is then pumped along a pipe to the first spray nozzle and the anionic detersive surfactant is injected into the pipe before the first aqueous slurry is sprayed from the first spray nozzle.
• the first aqueous slurry is passed through a first pump prior to addition of the anionic detersive surfactant and then passed through a second pump before passing to the first spray nozzle.
• a gas may be introduced between the first pump and the second pump.
• a gas preferably air
• a gas can be injected directly into the slurry at any point before the spray nozzle, preferably between the first and second pumps.
• nitrogen-rich gas' we herein mean a gas that comprises at least 50wt% nitrogen.
• 'air' we herein mean atmospheric air.
• the second aqueous slurry is also transferred from the mixer, preferably through at least one pump, to a second spray nozzle in the same way as detailed above for the first aqueous slurry.
• the second aqueous slurry is prepared by mixing the sulphate and the water and if present, the anionic surfactant and sodium hydroxide, to form an aqueous premix, the aqueous premix is pumped through a pipe to the second spray nozzle, the silicate and polymer are independently injected into the pipe before the spray nozzle.
• the premix can be formed by mixing in any suitable vessel, such as a mixer, in the standard manner. Suitable mixers include vertical mixers, slurry mixers, tank agitators, crutcher mixers and the like.
• the independent injection of the silicate and the polymer can be carried out in any position after the mixer and before the spray nozzle. However, preferably injection is carried out after the premix has been transferred through at least one pump, although injection can be carried out before the premix has been transferred through at least one pump. In a preferred embodiment, the premix is transferred through at least two pumps, and injection is carried out after the premix has been transferred through the first pump but before the premix enters the second pump.
• a nitrogen-rich gas preferably air
• nitrogen-rich gas may be injected into the slurry at any point before the spray nozzle, preferably between the first and second pumps.
• injection of nitrogen-rich gas into the slurry introduces gas bubbles into the slurry. These remain in the slurry during spray-drying and so are captured in the spray-dried particles. This provides the particles with a lower bulk density.
• nitrogen-rich gas' we herein mean a gas comprising at least 50wt% nitrogen.
• 'air' we herein mean atmospheric air.
• the pipe carrying the first aqueous slurry and separately the pipe carrying the second aqueous slurry and premix are at a pressure between 3x10 5 and 1x10 6 Pa.
• step (c) it may be preferred that additionally sodium chloride is contacted to the first aqueous slurry, the second aqueous slurry, or both, after the mixer and before the spray nozzle.
• the first aqueous slurry is sprayed through the first spray nozzle into a spray-drying tower, and the second aqueous slurry is independently sprayed through the second spray nozzle into the spray-drying tower.
• the first and second aqueous slurries are independently at a temperature of from 60°C to 130°C when they are sprayed through the spray nozzles into a spray-drying tower.
• Suitable spray-drying towers are co-current or counter-current spray-drying towers.
• the slurries are typically sprayed at a pressure of from 3x10 6 Pa to 1x10 7 Pa.
• the exhaust air temperature is in the range of from 60°C to 100°C.
• the sulphate when added to the aqueous slurry, has a volume average particle size of from 10 micrometers to 50 micrometers, preferably from 20 micrometers, or from 30 micrometers, and preferably to 45 micrometers, or even to 42 micrometers.
• the volume average particle size of the sulphate can be determined by any conventional means, such as light scattering, for example using a sympatec particle size analyser.
• the particle size of the inorganic salt can be controlled (i.e. reduced) by any suitable means, such as dry grinding (e.g. using pin mills) or wet grinding (e.g. using colloid mill).
• dry grinding e.g. using pin mills
• wet grinding e.g. using colloid mill
• the first spray nozzle is at a position higher up the spray drying tower than the second nozzle.
• the spray-drying tower is heated from the bottom. Hence the hottest air exists at the bottom of the tower, with cooler air nearer the top of the tower.
• the slurry droplets encounter cooler air. This reduces the likelihood of the first particle being overheated in the tower and so damaging the components of the first particle.
• the second particle which comprises large quantities of sulphate is more heat resistant, and so can be introduced at a point further down the tower where the hotter air exists.
• a first detergent POWDER A was prepared, comprising 29.6wt% of a Spray Dried Surfactant particle comprising 80wt% LAS and 20wt% sulphate and having a bulk density of 310g/l (manufactured by Quin Ting Chemicals, China), and 30.4wt% of Sodium Sulphate (bulk density: 1200 g/l), blended in a batch rotating mixer.
• a second detergent POWDER B was prepared comprising 29.6wt% of a Spray Dried Surfactant particle comprising 80wt% LAS and 20wt% sulphate and having a bulk density of 310g/l (manufactured by Quin Ting Chemicals, China), and 80wt% of a second spray-dried particle (bulk density: 400 g/l), blended in a batch rotating mixer.
• the second spray dried particle was manufactured via spray drying of an aqueous slurry composed of sodium sulphate having a particle size of between 10 and 50 microns, water, anionic surfactant and acrylate/maleate co-polymer.
• the slurry was prepared in at 80°C in a crutcher making vessel and the slurry was pumped through a standard spray system pressure nozzle and atomized into a counter current spray drying tower at an air inlet temperature of 275 °C. The atomized slurry was dried to produce a solid mixture, which was then cooled and sieved to remove oversize material (>1.8mm) to form a spray-dried powder.
• Table 1 Component %w/w Sodium silicate salt 10.0 Linear alkyl benzene sulphonate 9.6 Sodium sulphate 73.7 Water 1.0 Acrylate/maleate copolymer 3.4 Total Parts 100.0

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