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
  • C11D17/00—Detergent materials or soaps characterised by their shape or physical properties
  • C11D17/0047—Detergents in the form of bars or tablets
  • C11D17/0065—Solid detergents containing builders
  • C11D17/0073—Tablets
  • C11D17/0078—Multilayered tablets
• • 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
  • C11D1/00—Detergent compositions based essentially on surface-active compounds; Use of these compounds as a detergent
  • C11D1/66—Non-ionic compounds
  • C11D1/72—Ethers of polyoxyalkylene glycols
• • 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
  • C11D1/00—Detergent compositions based essentially on surface-active compounds; Use of these compounds as a detergent
  • C11D1/66—Non-ionic compounds
  • C11D1/83—Mixtures of non-ionic with anionic compounds
• • 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
  • C11D17/0047—Detergents in the form of bars or tablets
  • C11D17/0065—Solid detergents containing builders
  • C11D17/0073—Tablets
  • C11D17/0086—Laundry tablets
• • 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
• • 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
  • C11D3/12—Water-insoluble compounds
  • C11D3/124—Silicon containing, e.g. silica, silex, quartz or glass beads
  • C11D3/1246—Silicates, e.g. diatomaceous earth
  • C11D3/128—Aluminium silicates, e.g. zeolites
• • 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
  • C11D1/00—Detergent compositions based essentially on surface-active compounds; Use of these compounds as a detergent
  • C11D1/02—Anionic compounds
  • C11D1/12—Sulfonic acids or sulfuric acid esters; Salts thereof
  • C11D1/14—Sulfonic acids or sulfuric acid esters; Salts thereof derived from aliphatic hydrocarbons or mono-alcohols
  • C11D1/146—Sulfuric acid esters
• • 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
  • C11D1/00—Detergent compositions based essentially on surface-active compounds; Use of these compounds as a detergent
  • C11D1/02—Anionic compounds
  • C11D1/12—Sulfonic acids or sulfuric acid esters; Salts thereof
  • C11D1/28—Sulfonation products derived from fatty acids or their derivatives, e.g. esters, amides

Definitions

• the present invention relates to detergent compositions in tablet form containing nonionic surfactants.
• Tablets have various advantages over powdered products: for example, they do not require measuring and so are easier to dose, and they can be more economically stored as they are compact.
• Detergent tablets are generally made by compressing or compacting a detergent powder. It has proved difficult to strike a balance between tablet strength and the ability to disintegrate and disperse in the wash liquor. Tablets formed using only a light compaction pressure tend to crumble and break up on handling and packing; while more strongly compacted tablets may be sufficiently cohesive but will then fail to disperse at a sufficient rate and to an adequate extent in the wash liquor.
• Nonionic surfactants have beneficial cleaning characteristics when included in detergent formulations, especially in removing oily soil from fabrics. However, when in contact with aqueous solutions nonionic surfactants tend to form viscous phases which impede dissolution. In tablets the problem is exacerbated.
• EP 355 626A discloses a detergent tablet containing zeolites, builder salts, anionic surfactants and nonionic surfactants.
• the tablet is made by mixing two preformed components (A) and (B), wherein (A) contains the whole amount of anionic surfactant and (B) contains 75-100 wt% of the nonionic surfactant.
• the tablets are claimed to have good resistance to breaking up prior to use yet dissolve quickly in the washing machine.
• a detergent tablet containing a detergency builder and anionic detergent active has been disclosed in EP 466 485A (Unilever).
• the problem of poor dissolution is substantially alleviated by ensuring that the anionic detergent-active compounds present are not distributed widely through the tablet, but are concentrated in discrete domains within a continuous phase containing little or no anionic detergent-active compound.
• Nonionic surfactants may optionally be treated similarly.
• Particulate detergent compositions containing short-chain nonionic surfactants are disclosed in GB 1 460 646, GB 1 462 133, GB 1 462 134, GB 1 485 316 and GB 1 566 326 (Procter & Gamble); GB 1 519 433 and FR 2 303 850A (Rhone-Poulenc); EP 200 953A and WO 91 10718A (Henkel).
• the use of short-chain nonionic surfactants in detergent tablets to improve their disintegration and dissolution characteristics is not disclosed.
• the present invention accordingly provides a tablet of compacted detergent powder comprising a surfactant system comprising a nonionic surfactant, at least one detergency builder and optionally other detergent ingredients, characterised in that the nonionic surfactant comprises a condensation product of ethylene oxide with an aliphatic alcohol having an average alkyl chain length of less than C12.
• the invention further provides the use of a nonionic surfactant which is a condensation product of ethylene oxide with an aliphatic alcohol having an average alkyl chain length of less than C12 to improve the disintegration and dissolution in the wash liquor of a tablet of compacted detergent powder.
• a nonionic surfactant which is a condensation product of ethylene oxide with an aliphatic alcohol having an average alkyl chain length of less than C12 to improve the disintegration and dissolution in the wash liquor of a tablet of compacted detergent powder.
• the detergent tablet of the invention is characterised in that its surfactant system comprises ethoxylated nonionic surfactant having an average alkyl chain length of less than C12. This component will be referred to hereinafter as the short-chain nonionic surfactant.
• nonionic surfactants are generally mixtures containing a spread of chain lengths around an average value.
• the surfactant system is free of nonionic surfactants which are commercial materials having an average chain length of C12 and above.
• the short-chain nonionic surfactant is derived from an alcohol of which at least 25% by weight, more preferably at least 50 wt% and most preferably at least 75 wt%, has an alkyl chain length below C12.
• the surfactant system may be substantially free of any nonionic surfactant material having a chain length of C12 or above.
• ethoxylated alcohol nonionic surfactants having an average alkyl chain length from C9 to C 11.5 .
• the average number of ethylene oxide groups per mole of alcohol in the short-chain nonionic surfactant is preferably 8 or less, more preferably from 2 to 6.5, and advantageously from 2.5 to 6.
• the short-chain nonionic surfactant may consist wholly of straight-chain material, or may contain branched-chain material. Branched chain nonionic surfactants may advantageously give faster dissolution rates than their wholly straight chain counterparts.
• the level of free alcohol in the short-chain nonionic surfactant is as low as possible: preferably less than 5 wt% and more preferably less than 1 wt% of the total nonionic surfactant.
• Ethoxylates Dobanol 91-2.5 2.5 EO Dobanol 91-5 5 EO Dobanol 91-6 6 EO Dobanol 91 4-6 4-6 EO Nominal description: C9 ⁇ 11 alcohol with 20-25% branching (C1-C4). Average chain length: 10.14 Chain length distribution: C8 linear 0.7 0.7 C9 linear 17.5 19.0 C8 2-methyl 1.0 C7 2-ethyl 0.3 C6 2-propyl 0.2 C10 linear 40.7 45.8 C9 2-methyl 2.9 C8 2-ethyl 1.0 other branched 1.2 C11 linear 25.5 33.3 C10 2-methyl 2.4 C9 2-ethyl 1.0 Other branched 4.4 C12 linear 0 1.6 branched 1.6
• Ethoxylates Lialet 111-4 4 EO Lialet 111-5 5 EO Lialet 111-6 6 EO Lialet 111-4-6 4-6 EO Lialet 111 6.9 6.9 EO Nominal description: C11 alcohol with 50-60% branching (C1-C4). Average chain length: 11.0 Chain length distribution: C11 linear 49.2 96.10 C10 2-methyl 17.3 C9 2-ethyl 9.3 C8 2-propyl 9.7 C7 2-butyl and C6 2-pentyl 10.6
• Acropol* 91 4-6 ex Exxon C9 ⁇ 11 chain, 35% branching (C1 ⁇ 4), 4-6 EO
• Dobanol* 111 series ex Shell 98.5% C11, with traces of C10 and C12 Synperonic* 91-4-6 ex ICI: C9 ⁇ 11 chain, 60% branching (C1), 4-6 EO Lialet* 91 4-6 ex Enichem: C9 ⁇ 11 chain, 60% branching (C1 ⁇ 4), 4-6 EO Inbentin* C10E4 ex Kolb: C10 linear chain, 4 EO
• Longer-chain commercial nonionic surfactants which are preferably absent from the tablets of the invention include the following materials: Coconut-based materials such as the Lorodac* series ex DAC Chemicals: C12-C16, average chain length 12.75 Synperonic* nonionics ex ICI, eg Synperonic A3 (3EO): C13 ⁇ 15, average chain length 13.65: C13 linear 44.0 67.2 C12 2-methyl 11.9 C11 2-ethyl 3.8 C10 2-propyl 3.1 C9 2-butyl and C8 2-pentyl 4.4 C15 linear 20.9 35.1 C14 2-methyl 2.4 C13 2-ethyl 1.0 C12 2-propyl 0.8 C11 2-butyl and C10 2-pentyl and C9 2-hexyl 2.4
• the nonionic surfactants may be concentrated in discrete domains as disclosed in EP 466 485A (Unilever). Since the nonionic detergent compounds are generally liquids, these domains are preferably formed from particulate carrier material impregnated by the nonionic detergent-active compound. Suitable carrier materials include zeolite; zeolite granulated with other materials, for example Wessalith CS (Trade Mark), Wessalith CD (Trade Mark), Vegabond GB (Trade Mark); sodium perborate monohydrate; Burkeite (a spray-dried sodium carbonate/sodium sulphate double salt) as disclosed in EP 221 776A (Unilever).
• zeolite zeolite granulated with other materials, for example Wessalith CS (Trade Mark), Wessalith CD (Trade Mark), Vegabond GB (Trade Mark); sodium perborate monohydrate; Burkeite (a spray-dried sodium carbonate/sodium sulphate double salt)
• nonionic detergent compounds which may be present in the tablet such as long-chain tertiary amine oxides, tertiary phosphine oxides, and dialkyl sulphoxides.
• Nonionic detergent-active compounds may be present in the tablet at an amount from 2 to 50 wt%, preferably from 5 to 30 wt%.
• the tablets of the invention may contain other surfactants, provided that longer-chain ethoxylated nonionic surfactants are not present in such amounts that the average alkyl chain length of the total nonionic surfactant rises to C12 or above.
• the total amount of detergent-active material in the tablet of the invention is suitably from 5 to 50% wt%, preferably from 5 to 30 wt%.
• Detergent-active material present other than the nonionic surfactants may be other anionic (soap or non-soap), cationic, zwitterionic, amphoteric, or any combination of these.
• Anionic detergent-active compounds may be present in an amount of from 0 to 40 wt%, preferably from 0 to 20 wt%. It is preferred if the ratio of nonionic surfactant to anionic surfactant is within the range of 2:8 to 9:1.
• Synthetic 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 sulphosuccinate; and fatty acid ester sulphonates.
• soaps of fatty acids are preferably sodium soaps derived from naturally occurring fatty acids, for example, the fatty acids from coconut oil, beef tallow, sunflower or hardened rapeseed oil.
• a preferred embodiment of the invention contains alkyl sulphate, preferably primary alkyl sulphate (PAS), as the anionic surfactant.
• PAS primary alkyl sulphate
• Branched PAS for example as described in EP 439 316A (Unilever), may be preferred.
• An especially preferred embodiment of the invention contains a PAS adjunct wherein the PAS is on a carrier as described previously for nonionic surfactants.
• the detergent tablets of the invention contain one or more detergency builders, suitably in an amount of from 5 to 80 wt%, preferably from 20 to 60 wt%.
• the invention is of especial relevance to tablets derived from detergent compositions containing alkali metal aluminosilicates and/or alkali metal carbonate as builders, since such tablets appear to have a particular tendency to harden and so exhibit disintegration and dispersion problems.
• Alkali metal (preferably sodium) aluminosilicates may suitably be incorporated in amounts of from 5 to 60% by weight (anhydrous basis) of the composition, and may be either crystalline or amorphous or mixtures thereof, having the general formula: 0.8-1.5 Na2O. Al2O3.0.8-6 SiO2
• the preferred sodium aluminosilicates contain 1.5-3.5 SiO2 units (in the formula above). Both the amorphous and the crystalline materials can be prepared readily by reaction between sodium silicate and sodium aluminate, as amply described in the literature.
• Suitable crystalline sodium aluminosilicate ion-exchange detergency builders are described, for example, in GB 1 429 143 (Procter & Gamble).
• the preferred sodium aluminosilicates of this type are the well-known commercially available zeolites A and X, and mixtures thereof.
• the zeolite may be the commercially available zeolite 4A now widely used in laundry detergent powders.
• the zeolite builder incorporated in the compositions of the invention is maximum aluminium zeolite P (zeolite MAP) as described and claimed in EP 384 070A (Unilever).
• Zeolite MAP is defined as an alkali metal aluminosilicate of the zeolite P type having a silicon to aluminium ratio not exceeding 1.33, preferably within the range of from 0.90 to 1.33, and more preferably within the range of from 0.90 to 1.20.
• zeolite MAP having a silicon to aluminium ratio not exceeding 1.07.
• the calcium binding capacity of zeolite MAP is generally at least 150 mg CaO per g of anhydrous material.
• zeolite MAP gives two particular advantages: it is a more effective builder than zeolite 4A, and, quite independently, it enables higher total surfactant levels, and more nonionic-rich surfactant systems, to be incorporated without processing problems.
• zeolite MAP as a carrier for liquid detergent ingredients is described and claimed in EP 521 635A (Unilever).
• Preferred zeolite MAP for use in the present invention is especially finely divided and has a d50 (as defined below) within the range of from 0.1 to 5.0 microns, more preferably from 0.4 to 2.0 microns and most preferably from 0.4 to 1.0 microns.
• the quantity "d50” indicates that 50 wt% of the particles have a diameter smaller than that figure, and there are corresponding quantities "d80", "d90” etc.
• Especially preferred materials have a d90 below 3 microns as well as a d50 below 1 micron.
• Alkali metal carbonates may also be suitably incorporated into the tablets in amounts from 0 to 60%, preferably from 2 to 40 wt%.
• the preferred alkali metal carbonate is that of sodium.
• An alternative builder system for use within this invention comprises an alkali metal carbonate/calcite system.
• Inorganic builders may be present other than the alkali metal carbonates; while organic builders include polycarboxylate polymers such as polyacrylates, acrylic/maleic copolymers, and acrylic phosphinates; monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono-, di- and trisuccinates, carboxymethyloxysuccinates, carboxymethyloxymalonates, dipicolinates, hydroxyethyliminodiacetates; polycarboxylate polymers; and organic precipitant builders such as alkyl- and alkenylmalonates and succinates, and sulphonated fatty acid salts.
• polycarboxylate polymers such as polyacrylates, acrylic/maleic copolymers, and acrylic phosphinates
• monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono-, di- and trisuccinates, carboxymethyloxy
• Especially preferred supplementary builders are polycarboxylate polymers, more especially polyacrylates and acrylic/maleic copolymers, suitably used in amounts of from 0.5 to 15 wt%, especially from 1 to 10 wt%; and monomeric polycarboxylates, more especially citric acid and its salts, suitably used in amounts of from 3 to 35 wt%, more preferably from 5 to 30 wt%.
• Preferred tabletted compositions of the invention preferably do-not contain more than 5 wt% of inorganic phosphate builders, and are desirably substantially free of phosphate builders.
• phosphate-built tabletted compositions are also within the scope of the invention.
• Fully formulated laundry detergent compositions in accordance with the present invention may additionally contain any suitable ingredients normally encountered, for example, inorganic salts such as sodium silicate or sodium sulphate; antiredeposition aids such as cellulose derivatives and acrylate or acrylate/maleate polymers; fluorescers; bleaches, bleach precursors and bleach stabilisers; proteolytic and lipolytic enzymes; dyes; coloured speckles; perfumes; foam controllers; fabric softening compounds.
• inorganic salts such as sodium silicate or sodium sulphate
• antiredeposition aids such as cellulose derivatives and acrylate or acrylate/maleate polymers
• fluorescers bleaches, bleach precursors and bleach stabilisers
• proteolytic and lipolytic enzymes such as cellulose derivatives and acrylate or acrylate/maleate polymers
• fluorescers bleaches, bleach precursors and bleach stabilisers
• proteolytic and lipolytic enzymes such as cellulose derivatives and acrylate or acryl
• Tablet lubricants include calcium, magnesium and zinc soaps (especially stearates), talc, glyceryl behenate, Myvatex (Trade Mark) TL ex Eastman Kodak, sodium benzoate, sodium acetate, polyethylene glycols, and colloidal silicas (for example, Alusil (Trade Mark) ex Crosfield Chemicals Ltd).
• disintegrants include organic materials such as starches, for example, corn, maize, rice and potato starches and starch derivatives, such as Primojel (Trade Mark) carboxymethyl starch and Explotab (Trade Mark) sodium starch glycolate; celluloses and cellulose derivatives, for example, Courlose (Trade Mark) and Nymcel (Trade Mark) sodium carboxymethyl cellulose, Ac-di-Sol (Trade Mark) cross-linked modified cellulose, and Hanfloc (Trade Mark) microcrystalline cellulosic fibres; and various synthetic organic polymers, notably polyethylene glycol and crosslinked polyvinyl pyrrolidone, for example, Polyplasdone (Trade Mark) XL or Kollidon (Trade Mark) CL, bentonite clay, citric acid (preferred), malic acid or tartaric acid, in combination with alkali metal carbonate or bicarbonate.
• starches for example, corn, maize, rice and potato starches and starch derivatives, such as Primojel (Tra
• Tablet binders are well known in the art and include natural gums (form example acacia, tragaenth) and sugars (for example glucose, sucrose). As indicated previously, some ingredients may give both functional wash benefits and tabletting benefits.
• the detergent tablet of the invention may be, and preferably is, formulated for use as a complete heavy-duty fabric washing composition.
• the powder used to form the tablets by compaction may contain ingredients having different mean particle sizes and distributions, but preferably the starting powder should have an initial granule size in the range 75-1500 micrometres.
• the smaller particle sizes give smoother tablets with lower porosities whereas the larger particle sizes give tablets with a granular appearance and higher porosities. It is preferred, with the larger particle sizes, to have present a binder which enables the tablet to be formed at lower compaction pressures.
• each tablet may contain sufficient of every component to provide the correct amount required for an average washload, it is convenient if each tablet contains a submultiple quantity of the composition required for average washing conditions, so that the consumer may vary the dosage according to the size and nature of the washload.
• tablet sizes may be chosen such that two tablets are sufficient for an average washload; one or more further. tablets may be added if the washload is particularly large or soiled; and one only tablet may be used if the load is small or only lightly soiled.
• larger subdivisible tablets representing a single or multiple dose may be provided with scorings or indentations to indicate unit dose or submultiple unit dose size to the consumer and to provide a weak point to assist the consumer in breaking the tablet if appropriate.
• the weight of the tablet will suitably range from 10 to 160 g, preferably from 20 to 50 g, depending on the wash conditions under which it is intended to be used, and whether it represents a single dose, a multiple dose or a submultiple dose.
• the tablet may be of any suitable shape, but for manufacturing and packaging convenience is preferably of uniform cross-section, for example, circular or rectangular.
• the tablet of the invention may be homogeneous, or may consist of more than one discrete region: for example, two or more layers of different composition may be present, or a core region may be wholly surrounded by an outer region of different composition.
• the diameter of the tablet will suitably range from 1 to 10 cm, preferably from 2 to 6 cm.
• the tablets of the invention are prepared by compaction of a particulate detergent composition.
• the preferred bulk density of the detergent powder is at least 700 g/litre, more preferably 800 g/litre. Any suitable. tabletting apparatus may be used.
• the disintegration time will vary with the compaction pressure used to form the tablet. If the compaction pressure is too low, the tablet will tend to crumble and break up in the dry state, on handling and packaging; an increase in compaction pressure will improve tablet integrity, but eventually at the expense of disintegration time in the wash liquor.
• the optimum compaction pressure will depend to some extent on the starting composition; for example, a formulation containing a high proportion of organic ingredients (for example, surfactants) and a low proportion of inorganic salts may require a compaction pressure lower than that required for a formulation containing a lower proportion of organic ingredients and a higher proportion of inorganic salts; and a dry-mixed formulation will generally required a higher pressure than will a spray-dried powder.
• the diametral fracture stress ⁇ o 2P Dt
• ⁇ o the diametral fracture stress (Pascals)
• P the applied load to cause fracture (Newtons)
• D the tablet diameter (metres)
• t the tablet thickness (metres).
• Tablets of the invention preferably have a diametral fracture stress of at least 5 kPa, and more preferably at least 7 kPa.
• Preweighed tablets were placed in a cage of perforated metal gauze (7 cm x 7 cm x 6 cm) having apertures about 5mm square per cm2. The cage was then suspended in a beaker of demineralised water at 23°C and rotated at 80 rpm. The mass of tablet dissolved was calculated by a standard conductance procedure which involved measuring the conductance of the water at a given time and comparing this reading with that obtained from a fully dissolved powder of identical formulation and weight.
• the tablet is capable of dissolving to an extent of 60% by weight in 15 minutes. More preferably the tablet will be capable of dissolving to an extent of 75% by weight in 15 minutes.
• the dissolution of the tablets was studied in a Miele W756 front-loading automatic washing machine.
• the tablet was placed in the drum of the machine, the machine was programmed on the economy main wash with a cold water fill (10.5 litres demineralised water, isothermal at 11°C). No load was present.
• the percentage of the tablet dissolved was calculated using the standard conductance procedure described above.
• Tablets were placed in an experimental perspex washing machine.
• the programme of the washing machine was based upon the cotton cycle of the Spanish Zanussi (using 10 litres of cold Wirral water). The times taken for 50% and 90% of the tablet to dissolve were recorded. The standard conductance test as described above was used to calculate the weight of tablet dissolved.
• Detergent base powders were prepared to the following general formulation: Base powder wt% Zeolite 51.2 Sodium citrate 8.5 Water 14.8 Postdosed Nonionic surfactant 25.5
• the base powders were prepared by spray-drying.
• the nonionic surfactant was then stirred into the base powder and fluid bed mixed for 10 minutes at 70°C, and the powders were then allowed to weather.
• the tablets were produced using the Instron Universal Testing Machine at constant speed. Tablets so produced had end fracture strengths of 5 or 15 kPa and respectively thicknesses of 12.2 mm or 10.8 mm.
• the nonionic surfactants used were as described below: Example Nonionic surfactant Examples A and B Synperonic A7 (ICI) Examples C and D Coco 6.5 EO (Kolb) Examples 1 and 2 Dobanol 91-6 T (Shell) Examples 3 and 4 Alfonic 1012-62 (Vista)
• Table 1 Example Fracture Weight Tablet Dissolved (%) after Stress 3 min 7 min 11 min 15 min A 5 kPa 9 19 35 49 B 15 kPa 6 18 34 43 C 5 kPa 13 30 57 72 D 15 kPa 7 29 42 50 1 5 kPa 58 83 97 100 2 15 kPa 36 59 73 85 3 5 kPa 55 82 97 100 4 15 kPa 30 58 71 82
• High-bulk-density granular detergent compositions were prepared to the following formulations:
• the base powders were produced by spray-drying, and further ingredients were post dosed. Tablets were produced using the Instron Universal Testing Machine at constant speed. The tablets had fracture strengths of 5 kPa and 15 kPa with tablet thicknesses of 18.5 mm and 16.6 mm respectively.
• Example G Example 9 Base powder wt% wt% Zeolite 4A 30 30 Sodium citrate 5 5 Synperonic A7 10.22 0.22 Dobanol 91-5 - 10.00 Water 8.7 8.7 Postdosed Perborate monohydrate 14 14 TAED (83%) 7.4 7.4 Calcium EDTMP (33%) 0.37 0.37 Antifoam granule 3.0 3.0 Savinase 1.1 1.1 Sodium carbonate 13.0 13.0 PAS noodles 6.7 6.7 100 ⁇ 100 ⁇ * 89-90% Coconut PAS (Empicol LZV/E Trade Mark ex Albright & Wilson), as described in EP 466 485A (Unilever).
• Tablets were manufactured on the Instron using the 45mm diameter die and 45g of powder.
• Dissolution rates were measured by Machine Test B described previously, and were as shown in Table 5.
• Table 5 Example Fracture Stress (kPa) Time for 50% to dissolve (min) Time for 90% to dissolve (min) G 16.3 4.75 13 9 16.2 3.75 8.5
• Table 5 demonstrates that short chain nonionic surfactants improve dissolution rates in a mixed surfactant system.
• Tablets were compacted from detergent compositions as described below, at a compaction pressure of 15 kPa.
• Tablets were prepared by compaction of a high bulk density detergent powder having the following formulation (in weight %): Nonionic base granule Dobanol 91-6T 8.3-8.9 Zeolite 4A 28.2-29.6 Sodium carbonate 14.2-15.1 Acrylic/maleic copolymer 4.3-4.6 SCMC 0.5 Fluorescers 0.21 Polyethylene glycol 1500 2.4-6.0 Moisture 7.0-7.4 PAS adjunct (see earlier Examples) 5.7 Postdosed ingredients Sodium perborate monohydrate 14.0 TAED granules 7.4 Calcium EDTMP 0.4 Antifoam granules 3.0 Perfume 0.5 Protease granules 0.8 Lipolase granules 0.2
• a nonionic base granule was prepared by granulating the sodium carbonate (light ash) and zeolite 4A with the Dobanol 91-6T, aqueous polyacrylic acid, SCMC and fluorescers in a batch high-speed mixer/granulator (Fukae (Trade Mark) FS100), followed by drying in a batch fluid bed dryer, screening to a 250-1700 micron fraction.
• Fukae Trade Mark
• the dried granular material was coated with the polyethylene glycol 1500 by spraying it on as a melt, from a pressurised kettle maintained at 60-70°C, in a batch rotary mixer, and screened again to remove oversize material.
• PAS adjunct which had the formulation given in Examples 10 and 11, was prepared by dry neutralisation: PAS acid was sprayed onto zeolite and carbonate and neutralised in situ by the carbonate. This too was screened to 250-1700 micrometres.
• the nonionic base granule, the PAS adjunct and the remaining ingredients were mixed together in a batch rotary mixer.
• Tabletting was carried out using the Manesty single punch eccentric press (Thomson and Capper, Runcorn, Cheshire, England).
• the tablets of thickness 45 mm and diameter 29.1-29.3 mm and each containing 50 g of powder, generally had fracture strengths of 10-13 kPa.
• the tablets exhibited excellent dissolution characteristics and cleaning performance.
• 25 g and 50 g tablets were prepared, as in earlier Examples, by compacting high bulk density detergent powders.
• Nonionic surfactants were adsorbed onto Wessalith (Trade Mark) CD, a commercial zeolite 4A/polyacrylate granulated carrier material ex Degussa, at a level of 25.5 wt%, and the postdosed ingredients used in Examples 5-8 (37.9 wt%) admixed.
• the tablets were prepared to a strength of 15 kPa.
• the nonionic surfactants used were as follows:
• the tablets (2 x 50 g or 4 x 25 g) were used in a 40°C wool wash (low agitation) in the Miele machine, with a 1.4 kilo clean load.
• the water inlet temperature was 20°C.
• the tablets were dosed in a dispensing device of the type used for high bulk density powders.
• the following residues (g) were found in the dispensing device at the end of the main wash (each result being the mean of three values): H 4 x 25 g 36.1 2 x 50 g 43.1 J 4 x 25 g 26.0 2 x 50 g 31.4 13 4 x 25 g 4.2 2 x 50 g 13.0 14 4 x 25 g 9.9 2 x 50 g 26.7
• the tablets were prepared to strengths ranging from 9 to 14 kPA, using the Manesty machine used in Example 12.
• Tablet strength T90 in economy wash Residue in wool wash (g) K 9 kPa 3.5-5.5 5-20 g 15 12 kPa 3.5-5.0 5-10 g 16 14 kPa 3.5-5.0 5-10 g

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• 1992
  • 1992-11-16 GB GB929224015A patent/GB9224015D0/en active Pending
• 1993
  • 1993-11-15 ES ES93309120T patent/ES2097994T3/es not_active Expired - Lifetime
  • 1993-11-15 DE DE1993607660 patent/DE69307660T2/de not_active Revoked
  • 1993-11-15 EP EP19930309120 patent/EP0598586B1/fr not_active Revoked

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