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
  • C11D3/16—Organic compounds
  • C11D3/18—Hydrocarbons
• • 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
  • C11D17/065—High-density particulate detergent compositions

Definitions

• the present invention relates to detergent powders prepared at least in part by spray-drying and intended for use in drum-type front-loading washing machines.
• the invention is of especial applicability to powders containing no, or reduced levels of, phosphate builders and to powders of high bulk density.
• the incorporation of these materials via the slurry also improves powder structure and, when anionic surfactant is present, raises the bulk density.
• the invention comprises a spray-dried detergent powder comprising one or more anionic and/or nonionic surfactants and further comprising an additive which is a water-insoluble material substantially insoluble in anionic and nonionic surfactants, having a melting point within the range of from 30 to 100°C and having a contact angle to water of at least 75°, the additive being present in an amount of from 0.1 to 6.0% by weight and the powder giving a dispenser residue at least 10% by weight less than that of a comparative powder without the additive, as measured in a Philips (Trade Mark) AWB 126/7 washing machine using 100 g powder and 5 litres of water at 20°C over a period of 1 minute.
• an additive which is a water-insoluble material substantially insoluble in anionic and nonionic surfactants, having a melting point within the range of from 30 to 100°C and having a contact angle to water of at least 75°, the additive being present in an amount of from 0.1 to 6.0% by weight and the powder giving a dispenser residue at least 10%
• the invention provides a process for the preparation of a detergent powder comprising one or more anionic and/or nonionic surfactants and further comprising an additive which is a water-­insoluble material substantially insoluble in anionic and nonionic surfactants, having a melting point within the range of from 30 to 100°C and having a contact angle to water of at least 75°, the process including the step of spray-drying an aqueous slurry, the additive being incorporated in the slurry or sprayed onto the powder in an amount of from 0.1 to 6% by weight based on the powder, and the powder thus obtained giving a dispenser residue at least 10% by weight less than that of a comparative powder without the additive, as measured in a Philips (Trade Mark) AWB 126/7 washing machine using 100 g powder and 5 litres of water at 20°C over a period of 1 minute.
• an additive which is a water-­insoluble material substantially insoluble in anionic and nonionic surfactants, having a melting point within the range of from 30
• Detergent compositions containing foam control systems that include hydrocarbon waxes are disclosed in EP 87 233A, EP 109 247A and EP 206 522A (Unilever); GB 1 492 938, GB 1 492 939, GB 2 040 982B, EP 8 829A, EP 8 830A and JP 56 034797A (Procter & Gamble); DE 3 436 194A, US 4 590 194 and EP 150 386A (Henkel).
• US 4 196 104 (Procter & Gamble) discloses spraying an antistatic composition comprising a quaternary ammonium compound and a paraffin wax (as dispersion inhibitor) onto detergent base granules.
• the first aspect of the invention is a detergent powder prepared at least in part by spray-drying.
• the composition of the invention may be a fully formulated detergent composition prepared wholly by spray-drying; a spray-dried base to which other ingredients may be admixed to form a finished product; or a finished product of that type, comprising a spray-dried base in admixture with other ingredients.
• the detergent powder of the invention contains one or more anionic and/or nonionic surfactants, and a specified hydrophobic material that influences its dispensing behaviour in a particular manner.
• composition of the invention may also contain any of the materials conventionally included in detergent compositions. These are described in more detail below.
• the surfactant component is the surfactant component
• the total amount of surfactant present in the composition of the invention will generally range from 5 to 40% by weight, more preferably from 10 to 30% by weight and especially from 12 to 20% by weight. These figures are typical for fully formulated detergent compositions, and where a spray-dried base forms only part of such a composition the surfactant content of that base, as a percentage, may of course be higher.
• the invention is of especial applicability to compositions containing anionic surfactant.
• the high-foaming anionic surfactant tends to cause "puffing" (entrainment of air) in the slurry, so that highly porous particles are formed in the spray-drying tower. These particles may be very crisp and free-flowing, but may be of lower bulk density than desired.
• the incorporation in the slurry of an additive such as paraffin wax, in accordance with the present invention has been found to result in an increase in bulk density.
• the amount of anionic surfactant present is desirably at least 5% by weight, and may suitably be in the range of from 5 to 30% by weight, preferably from 5 to 10% by weight, these figures again being based on a fully formulated detergent composition.
• Anionic surfactants are well known to those skilled in the art. Examples include alkylbenzene sulphonates, particularly sodium linear alkylbenzene sulphonates having an alkyl chain length of C8-C15; primary and secondary alkyl sulphates, particularly sodium C12-C15 primary alcohol sulphates; olefin sulphonates; alkane sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates.
• alkylbenzene sulphonates particularly sodium linear alkylbenzene sulphonates having an alkyl chain length of C8-C15
• primary and secondary alkyl sulphates particularly sodium C12-C15 primary alcohol sulphates
• olefin sulphonates alkane sulphonates
• dialkyl sulphosuccinates and fatty acid ester sulphonates.
• the composition of the invention also contains one or more nonionic surfactants.
• Nonionic surfactants that may be used include the primary and secondary alcohol ethoxylates, especially the C12-C15 primary and secondary alcohols ethoxylated with an average of from 3 to 20 moles of ethylene oxide per mole of alcohol.
• the weight ratio of anionic surfactant to nonionic surfactant is preferably at least 0.67:1, more preferably at least 1:1, and most preferably within the range of from 1:1 to 0:1, in order to obtain the optimum detergency and foaming properties appropriate for front-loading automatic washing machines. These ratios of course apply to fully formulated products.
• a spray-­dried base that is to form only part of a product may contain a lower proportion of, or no, nonionic surfactant, the balance of the nonionic surfactant being added after the spray-drying tower.
• the characterising feature of the composition of the present invention is the presence of a low level (0.1-6.0% by weight) of a hydrophobic material.
• the hydrophobicity of the material is expressed in terms of its contact angle to water, which must be at least 75°, preferably at least 85°. Hydrocarbons are especially preferred.
• the melting point of the material is also important: it appears that the additive should be solid at ambient temperature but liquid at slurry-processing temperature (generally in the range of from 60 to 100°C).
• the melting point of the additive should lie within the range of from 30 to 100°C, preferably from 40 to 80°C.
• Preferred materials are paraffin waxes melting within the specified range, and preferably melting within the range of from 50 to 60°C. Paraffin oil liquid at ambient temperature has been found to be ineffective in the context of the present invention, and also tends to give wet, sticky powders with unacceptable flow properties.
• the hydrophobic material be substantially insoluble in the anionic and nonionic surfactant system present in the composition: the microcrystalline waxes of GB 1 492 938 and GB 1 492 939 (Procter & Gamble) are stated to be chosen for their solubility in the surfactant present, and are unsuitable for use in the present invention for that reason as well as for the reason that their melting points are too high.
• the hydrophobic material is preferably present in an amount of from 0.2 to 4% by weight. In a fully formulated product the optimum level for paraffin wax appears to be from 0.3 to 2% by weight.
• composition of the invention is prepared by a process which includes the step of spray-drying an aqueous crutcher slurry.
• This slurry will normally contain all those desired ingredients sufficiently heat-stable to survive the spray-drying process, notably anionic surfactants, builders, inorganic salts, sodium silicate, polymers and fluorescers. More heat-­sensitive ingredients can be postdosed to, or sprayed onto, the spray-dried base.
• the hydrophobic material characteristic of the invention may be incorporated. It may be included in the slurry, in which case it is preferably used in an amount of from 0.2 to 4.0% by weight, more preferably from 0.3 to 2.0% by weight, based on the final powder including any postdosed ingredients. It may be advantageous to premix the hydrophobic material with surfactant, especially nonionic surfactant, before admixture with other slurry ingredients.
• the second method by which the hydrophobic material may be incorporated in a detergent composition of the invention is by spraying it in liquefied form onto the spray-dried powder. If the final product is to include postdosed solid ingredients, for example, sodium perborate, bleach activator granules, enzyme granules or antifoam granules, the hydrophobic material should be sprayed on after addition of those ingredients so as to cover the whole powder.
• postdosed solid ingredients for example, sodium perborate, bleach activator granules, enzyme granules or antifoam granules
• the hydrophobic material may be melted and sprayed directly onto the powder.
• the hydrophobic material is then preferably used in an amount of from 2.0 to 6.0% by weight, more preferably from 3.0 to 4.0% by weight.
• the hydrophobic material is premixed with nonionic surfactant to form a coating composition which may then be sprayed onto the detergent powder.
• Lower levels of the hydrophobic material for example, 0.2 to 4.0%, preferably 0.3 to 2.0%, are then found to be effective.
• the coating composition consists essentially of 2-50% by weight of the hydrophobic material and 50-98% by weight of nonionic surfactant.
• the hydrophobic material is paraffin wax
• the coating composition desirably contains 8-15% by weight of paraffin wax and 85-92% by weight of nonionic surfactant.
• the paraffin wax, and if necessary the nonionic surfactant are melted to form the coating composition, which is applied as a liquid, suitably at a temperature of 40-60°C.
• the coating composition should be substantially free of other ingredients that might interfere with the beneficial effect of the hydrophobic material on dispensing.
• the incorporation of the hydrophobic material should effect a reduction in the residue of at least 10 percentage points, preferably at least 20 percentage points.
• a powder having essentially the same composition but with an inorganic salt (sodium carbonate or sodium sulphate) to make up the difference should be used.
• the present invention is therefore especially applicable to powders which, without the additive, give dispenser residues of at least 10%, more especially at least 20%, by weight. That is especially likely to be the case if the powder is a zero-phosphate composition built with crystalline (zeolite) or amorphous sodium aluminosilicate; if it contains less than 10% sodium silicate; or if it has a bulk density of 550 g/litre or more.
• zeolite crystalline
• amorphous sodium aluminosilicate if it contains less than 10% sodium silicate; or if it has a bulk density of 550 g/litre or more.
• the detergent powder of the invention can contain any of the ingredients conventionally present in compositions intended for the washing of fabrics in front-loading automatic washing machines.
• examples of such components include inorganic and organic detergency builders, other inorganic salts, sodium silicate, bleaches, fluorescers, polymers, lather control agents, enzymes and perfumes.
• the powder of the invention may contain one or more soaps of fatty acids, in addition to the non-­soap anionic surfactant mentioned above.
• the powder will also contaln one or more detergency builders.
• the invention is of especial applicability, as previously mentioned, to low- or zero-phosphate powders containing crystalline (zeolite) or amorphous aluminosilicate.
• Zeolite may suitably be present in an amount of from 20 to 80% by weight.
• Other, supplementary, builders may also be present, for example, polycarboxylate polymers such as polyacrylates, acrylic-maleic copolymers, or acrylic phosphinates; momomeric polycarboxylates such as nitrilotriacetates and ethylene diamine tetraacetates; inorganic salts such as sodium carbonate; and many other materials familiar to the skilled detergent formulator.
• the powder of the invention may contain sodium silicate.
• High levels of silicate can in themselves have a beneficial effect on dispensing, as well as on powder structure and prevention of machine corrosion, but are undesirable in powders containing aluminosilicate because the two components react together to form insoluble siliceous species.
• the present invention enables the dispensing behaviour of zeolite-built powders to be improved without a corresponding increase in the level of insoluble material. Accordingly, the invention is of especial applicability to powders containing less that 10% by weight, more especially less than 5% by weight, of sodium silicate.
• fluorescers include fluorescers, antiredeposition agents, inorganic salts such as sodium sulphate, enzymes, lather control agents, bleaches, bleach activators, and bleach stabilisers. These may be included in the spray-dried base powder or postdosed according to their known suitability for undergoing spray-drying processes and their compatibility with other slurry ingredients.
• Zero-phosphate detergent base powders containing various amounts of paraffin wax (melting point 52-54°C) or paraffin oil were prepared, by slurry-making and spray-drying, to the following nominal composition: Parts Sodium linear alkylbenzene sulphonate 9.0 Nonionic surfactant 1.0 Zeolite (anhydrous) 24.0 Acrylic/maleic copolymer* 4.0 Sodium carbonate 2.0 Minor ingredients 0.83 Moisture 10.0 Paraffin wax 0, 0.25, 0.5, 1.0, 2.0 or paraffin oil 1.0 Total 51-53 parts *Sokalan (Trade Mark) CP5 ex BASF.
• the full formulation of the base powder of Comparative Example B was identical to that of Example 3, except that the paraffin wax was replaced by paraffin oil.
• the dispensing residues of the base powders determined by the test described above, and their powder properties were as follows: A 2 3 4 Dispenser residue (%) 46 0 0 0 0 Bulk density (g/l) 540 585 525 586 DFR (ml/s) 108 115 117 109 Compressibility (% v/v) 36 29 31 30
• the dispenser residue of the base powder of Comparative Example B was 15%.
• Zero-phosphate detergent powders similar to those of Examples 1-4 but containing a higher level of anionic surfactant were prepared, to the following formulations (in weight %): Spray-dried base powder C 5 Sodium linear alkylbenzene sulphonate 11.1 11.1 Nonionic surfactant 1.2 1.2 Zeolite (anhydrous) 24.0 24.0 Acrylic/maleic copolymer* 4.0 4.0 Sodium carbonate 2.0 2.0 Sodium alkaline silicate 0.5 0.5 Sodium sulphate 1.3 1.3 Minor ingredients 0.83 0.83 Paraffin wax (m.pt. 52-54°C) 0 1.0 Moisture 9.50 9.95 *Sokalan (Trade Mark) CP5 ex BASF.
• a zero-phosphate detergent base powder similar to that of Comparative Example A was prepared, by slurry-making and spray-drying, to the following formulation: Parts % Sodium linear alkylbenzene sulphonate 9.0 18.37 Nonionic surfactant 1.0 2.04 Zeolite (anhydrous) 24.0 48.98 Acrylic/maleic copolymer* 4.0 8.16 Sodium carbonate 2.0 4.08 Minor ingredients 0.83 1.69 Moisture 8.17 16.68 *Sokalan (Trade Mark) CP5 ex BASF.
• Dispensing and powder properties were as follows: D 9 10 11 Wax/nonionic spray-on: Total (parts) 0 3.3 4.0 5.0 Total (% on base powder) 0 6.31 7.55 9.26 Dispenser residue (%) 37 0 0 0 0 Bulk density (g/ml) 450 512 Dynamic flow rate (ml/s) 108 105 Compressibility (% v/v) 27 21

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• Organic Chemistry (AREA)
• Detergent Compositions (AREA)

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Cited By (14)

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Citations (4)

• 1988
  • 1988-03-21 GB GB888806702A patent/GB8806702D0/en active Pending
• 1989
  • 1989-03-09 EP EP89200587A patent/EP0337523B2/de not_active Expired - Lifetime
  • 1989-03-09 ES ES89200587T patent/ES2042963T5/es not_active Expired - Lifetime
  • 1989-03-09 DE DE68906949T patent/DE68906949T3/de not_active Expired - Lifetime
  • 1989-03-15 CA CA000593788A patent/CA1317188C/en not_active Expired - Fee Related
  • 1989-03-20 AU AU31498/89A patent/AU620381B2/en not_active Ceased
  • 1989-03-21 ZA ZA892134A patent/ZA892134B/xx unknown
  • 1989-03-21 TR TR00242/89A patent/TR26791A/xx unknown

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