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
  • 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
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/02—Inorganic compounds ; Elemental compounds
  • C11D3/04—Water-soluble compounds
  • C11D3/06—Phosphates, including polyphosphates
• • 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
  • C11D3/39—Organic or inorganic per-compounds
  • C11D3/3942—Inorganic per-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
  • 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
  • C11D1/22—Sulfonic acids or sulfuric acid esters; Salts thereof derived from aromatic 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
  • 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

Definitions

• This invention relates to uses of sodium percarborate in detergent compositions in the form of tablets intended to be consumed when washing a single load of laundry.
• compositions for fabric washing there are a number of possible options. Such compositions have for many years been manufactured in particulate form, commonly referred to as powders. Detergent compositions can also be manufactured as liquids. Tablets, to which this invention relates, are yet another possibility.
• Anionic detergent actives are the most commonly used, usually together with nonionic detergent actives.
• anionic detergent actives which are commercially available, linear alkylbenzene sulphonate and primary alkyl sulphate are commonly used.
• particulate detergent compositions There has been a trend for particulate detergent compositions to be manufactured with a bulk density higher than 650 g/litre which is a departure from older practice when bulk densities were customarily lower.
• Detergent compositions in tablet form have, potentially at least, several advantages over powder products. They do not require the user to measure out a volume of powder or liquid. Instead one or several tablets provide an appropriate quantity of composition for washing a single load in a washing machine or possibly by hand. They are thus easier for the consumer to handle and dispense.
• Detergent compositions in tablet form are generally made by compressing or compacting a detergent powder which includes both detergent active and detergency builder. It is desirable that tablets have adequate strength when dry, yet disperse and dissolve quickly when added to wash water.
• Detergent tablets for fabric washing typically contain at least 5% by weight of detergent active. This serves as a binder, but can also retard disintegration and dissolution of a tablet. (By contrast, tablets for use in automatic dishwashing machines typically contain 2% by weight or less of detergent active, customarily a low-foaming nonionic detergent, as in WO96/23053 for instance).
• There have been a number of disclosures relating to the manufacture of detergent tablets for fabric washing which have both strength and rapidity of disintegration in water for example EP-A-522766.
• GB-A-1080066 teaches that tablets should have void space between particles in order to allow penetration of water into the tablet at the time of use.
• the teaching of this document is that the void volume should be from 35 to 60% of the total tablet volume.
• US-A-3081267 teaches that void space within a tablet and communicating with external air should be from 40 to 60% by volume of the tablet.
• GB 911204 and US-A-3 953 350 both describe detergent tablets including detergents with detergency builders and a specified proxygen bleach.
• the tablets When making tablets from particulate detergent composition, it is desirable that the tablets should dissolve/disintegrate rapidly when added to water for use, yet have a good mechanical strength prior to use. These properties are antagonistic. As more pressure is used when a tablet is compacted, so the tablet density and strength rise, but the speed of disintegration/dissolution goes down.
• This invention is concerned with tablets compacted from a detergent composition containing a substantial portion of water-soluble phosphate builder.
• the amount of peroxygen bleach is preferably at least 10% by weight of the composition.
• the amount may be not more than 25% or even 20% by weight.
• the peroxygen bleach is preferably distributed throughout the tablet, although it may be present as a multiplicity of granules distributed throughout the tablet.
• sodium percarbonate may be utilised in the form of granules with a water-soluble coating of a protective material serving to keep moisture away from the percarbonate until the time of use.
• Tablet density preferably lies in a range from 1040, 1050, or 1075 gm/litre up to 1300gm/litre.
• the tablet density may well lie in a range up to 1275, 1250 or even 1200gm/litre.
• Tablet density is inversely related to tablet porosity, which is conveniently expressed as the percentage of its volume which is air (i.e. empty space).
• the air content of a tablet can be calculated from the volume and weight of the tablet, provided the true density of the solid content is known.
• the latter can be measured by compressing a sample of the material under vacuum with a very high applied force, then measuring the weight and volume of the resulting solid object.
• the true density of a detergent composition is often about 1.6, in which case a tablet density range from 1040 to 1300g/litre is approximately 19 to 35% air by volume. Ranges of 1040 to 1250 or 1200g/litre approximates to 22 or 25% to 35% air by volume. A preferred range of 1070 to 1250g/litre approximates to 22 to 33% air by volume.
• part or all of the detergent active is anionic.
• anionic and nonionic detergent are in proportions from 1.5:1 to 4:1, better 1.8:1 to 3:1 or 4:1. These proportions give good cleaning.
• the nonionic detergent active is a mixture of a nonionic detergent, preferably an ethoxylated fatty alcohol, with HLB value over 11.0 and a nonionic detergent, preferably an ethoxylated fatty alcohol, with HLB value below 9.5, better below 9.0, in a weight ratio lying in a range from 3.1 to 1.3.
• the particulate composition which is compacted may be a mixture of particles of individual ingredients, but usually will comprise particles which themselves contain a mixture of ingredients. Such particles containing a mixture of ingredients may be produced by a granulation process and may be used alone or together with particles or single ingredients.
• the composition will contain detergent active and detergent builder. Other ingredients are optional, but usually there will be some other ingredients in addition to the detergent active and detergency builder.
• the amount of detergent active in a tablet is suitably from 5 or 8wt% up to 40 to 50wt%.
• Detergent-active material present may be anionic (soap or non-soap), cationic, zwitterionic, amphoteric, nonionic or any combination of these.
• Anionic detergent-active compounds may be present in an amount of from 0.5 to 40 wt%, preferably from 2%, 4% or 5% up to 30 or 40 wt%.
• Synthetic (i.e. non-soap) anionic surfactants are well known to those skilled in the art. Examples include alkylbenzene sulphonates, olefin sulphonates; alkane sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates.
• Primary alkyl sulphate having the formula ROSO 3 - M + in which R is an alkyl or alkenyl chain of 8 to 18 carbon atoms especially 10 to 14 carbon atoms and M + is a solubilising cation especially sodium, is commercially significant as an anionic detergent active.
• Linear alkyl benzene sulphonate of the formula where R is linear alkyl of 8 to 15 carbon atoms and M + is a solubilising cation, especially sodium, is also a commercially significant anionic detergent active.
• such linear alkyl benzene sulphonate or primary alkyl sulphate of the formula above, or a mixture thereof will be the desired anionic detergent and may provide 75 to 100wt% of any anionic non-soap detergent in the composition.
• the amount of non-soap anionic detergent lies in a range from 5 to 30 wt% of the composition, better 5 to 20 wt%.
• 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.
• Suitable nonionic detergent compounds which may be used include in particular the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example, aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide.
• Nonionic detergent compounds are alkyl (C 8-22 ) phenol-ethylene oxide condensates, the condensation products of linear or branched aliphatic C 8-20 primary or secondary alcohols with ethylene oxide, copolymers of ethylene oxide and propylene oxide, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylene-diamine.
• the primary and secondary alcohol ethoxylates especially the C 10-15 primary and secondary alcohols ethoxylated with an average of from 5 to 20 moles of ethylene oxide per mole of alcohol.
• the amount of nonionic detergent lies in a range from 1 to 20%, better 2% up to 15% or 20% by weight of the composition.
• non-soap anionic detergent especially linear alkyl benzene sulphonate or primary alkyl sulphate
• nonionic detergent especially ethoxylated fatty alcohol
• Products of this invention also include phosphate detergency builder, which may be an alkali metal orthophosphate, pyrophosphate or tripolyphosphate. Preferred is sodium tripolyphosphate.
• water-soluble builders which may be present are carbonates, e.g. sodium carbonate; and organic builders containing up to six carbon atoms, e.g. sodium tartrate, sodium citrate, trisodium carboxymethyloxysuccinate.
• the amount of phosphate or polyphosphate detergency builder is at least 20% by weight, often at least 26% or even at least 33% by weight of the overall composition.
• a preferred amount of sodium tripolyphosphate is 30 to 60% by weight.
• the total amount of detergency builder will generally lie in a range from 5 to 80wt% of the composition.
• the amount may be at least 10 or 15wt% and may lie in a range up to 50 or 60wt%.
• bleach activators also referred to as bleach precursors
• Preferred examples include peracetic acid precursors, for example, tetraacetylethylene diamine (TAED), now in widespread commercial use in conjunction with sodium perborate; and perbenzoic acid precursors.
• TAED tetraacetylethylene diamine
• activator used as 1 to 10% by weight of a composition.
• ingredients may also be present in the overall composition. These include sodium carboxymethyl cellulose, colouring materials, enzymes, fluorescent brighteners, germicides, perfumes and bleaches.
• Sodium alkaline silicate may be included, although the amount of this or at least the amount added as an aqueous liquid, is preferably restricted so as to keep to a particulate mixture prior to compaction.
• the detergent composition may incorporate a binder which is water-soluble and serves as a disintegrant by disrupting the structure of the tablet when the tablet is immersed in water, as taught in our EP-A-522766.
• Such a binder material should melt at a temperature of 35°C, better 40°C or above, which is above ambient temperatures in many temperate countries. For use in hotter countries it will be preferable that the melting temperature is somewhat above 40°C, so as to be above the ambient temperature.
• the melting temperature of the binder material should be below 80°C.
• Preferred binder materials are synthetic organic polymers of appropriate melting temperature, especially polyethylene glycol.
• Polyethylene glycol of average molecular weight 1500 melts at 45°C and has proved suitable.
• the particulate composition which is compacted should have a bulk density of at least 650 g/litre, preferably at least 700 g/litre, and advantageously at least 750 g/litre.
• Granular detergent compositions of high bulk density can be prepared by granulation and densification in a high-speed mixer/granulator, as described and claimed in EP 340013A (Unilever), EP 352135A (Unilever), and EP 425277A (Unilever), or by the continuous granulation/densification processes described and claimed in EP 367339A (Unilever) and EP 390251 A (Unilever).
• a suitable press will generally have a pair of mould parts which move relatively towards and away from each other to compact particulate material between them. They may move within a surrounding sleeve or similar structure.
• the density and strength of tablets varies with the pressure applied to compact the composition into tablets.
• the amount of pressure needed to obtain a density in the required range can be found by making tablets with varying amounts of applied force, and determining the density of the tablets obtained.
• the tablets may be made without any spray on of water after stamping the tablets.
• Tablets for use in fabric washing were made, starting with a base powder of the following composition: parts by weight Sodium linear alkylbenzene sulphonate 9.62 C 13-15 fatty alcohol 7EO 1.07 C 13-15 fatty alcohol 3EO 3.21 Soap 0.27 Sodium tripolyphosphate, type 1A 24.31 Sodium silicate 5.88 Sodium carboxymethyl cellulose 0.21 Acrylate/maleate copolymer 1.15 Salts, moisture and minor ingredients 8.9 54.60
• compositions thus contained the following percentages by weight: % by weight A B C Base powder 54.60 54.60 54.60 HPA sodium tripolyphosphate 21.22 21.22 20.12 TAED granules 3.35 3.35 3.35 Sodium carbonate 3.20 4.95 -- Sodium percarbonate 15.00 -- -- Sodium perborate monohydrate -- 13.25 -- Sodium perborate tetrahydrate -- -- 19.30 Anti-foam granule 1.16 1.16 1.16 Enzymes, phosphonate, perfume 1.47 1.47 1.47
• the amounts of persalt were chosen to give the same amounts of available oxygen.
• the sodium percarbonate was in the form of granules with a water-soluble coating.
• 35g portions of each composition were made into cylindrical tablets of 44 mm diameter, using a Carver hand press.
• the force applied to make the tablets was the same (300kg) in each case.
• the tablets were weighed and measured to determine their density which was found to be 1117gm/litre ⁇ 5% in each case.
• the strength of the tablets was determined by the following test of their diametral fracture stress. The test procedure was carried out using a testing machine with flat faces which were urged together by a measured force, such as an Instron Universal Testing Machine.
• the cylindrical tablet was placed between the platens of an Instron machine, so that the platens contact the curved surface of the cylinder at either end of a diameter through the tablet.
• the sample tablet was then compressed diametrically, by advancing the platens of the machine towards each other at a slow rate such as 1 cm/min until fracture of the tablet occurred, at which point the applied load required to cause fracture was recorded.
• tablets should have a DFS of at least 6KPa, better at least 8KPa.
• DFS will usually not need to exceed 40KPa, and a range from 10 to 40KPa is particularly preferred. Values of DFS up to at least 60KPa may be used, however.
• the break-up, dispersion and dissolution of tablets was measured by a test procedure in which a tablet is placed on a plastic sieve with 2mm mesh size which was immersed in 9 litres of demineralised water at ambient temperature of 22°C and rotated at 200 rpm. The water conductivity was monitored until it reached a constant value.
• the time for break up and dispersion of the tablets was taken as the time (T 90 ) for change in the water conductivity to reach 90% of its final magnitude. This was also confirmed by visual observation of the material remaining on the rotating sieve.

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• Inorganic Chemistry (AREA)
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• 1997
  • 1997-03-24 GB GBGB9706083.4A patent/GB9706083D0/en active Pending
• 1998
  • 1998-03-18 AU AU72106/98A patent/AU7210698A/en not_active Abandoned
  • 1998-03-18 BR BR9808044-0A patent/BR9808044A/pt not_active IP Right Cessation
  • 1998-03-18 WO PCT/EP1998/001769 patent/WO1998042816A1/en not_active Application Discontinuation
  • 1998-03-18 EP EP98919154A patent/EP0956332B2/en not_active Expired - Lifetime
  • 1998-03-18 DE DE69803832T patent/DE69803832T3/de not_active Expired - Fee Related
  • 1998-03-18 CN CN98805061A patent/CN1255940A/zh active Pending
  • 1998-03-18 PL PL98335880A patent/PL335880A1/xx unknown
  • 1998-03-18 ES ES98919154T patent/ES2172134T5/es not_active Expired - Lifetime
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  • 1998-03-18 GB GB9913960A patent/GB2335435B/en not_active Expired - Fee Related
  • 1998-03-18 CA CA002284005A patent/CA2284005A1/en not_active Abandoned
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