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
  • C11D11/00—Special methods for preparing compositions containing mixtures of detergents
  • C11D11/0082—Special methods for preparing compositions containing mixtures of detergents one or more of the detergent ingredients being in a liquefied state, e.g. slurry, paste or melt, and the process resulting in solid detergent particles such as granules, powders or beads
  • C11D11/0088—Special methods for preparing compositions containing mixtures of detergents one or more of the detergent ingredients being in a liquefied state, e.g. slurry, paste or melt, and the process resulting in solid detergent particles such as granules, powders or beads the liquefied ingredients being sprayed or adsorbed onto solid particles
• • 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
  • C11D1/22—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 detergent compositions, in particular to fluid mixtures containing high active concentrations of anionic and nonionic surfactants (HAMS), to processes for stabilising them and to processes for converting them into detergent powders.
• HAMS anionic and nonionic surfactants
• Sodium alkyl aryl sulphonates such as linear alkyl benzene sulphonates, (LAS) and sodium alkyl sulphates such as primary alcohol or alkyl sulphates (PAS) are particularly prone to produce light powders.
• LAS linear alkyl benzene sulphonates
• PAS primary alcohol or alkyl sulphates
• the active detergent (surfactants) must be sufficiently mobile at temperature below about 80°C to be atomised effectively and must be stable in this sprayable liquid form.
• Great Britain Patent No. 1,579,261 (Colgate-Palmolive Co.) relates to processes for converting various liquid or liquefiable detergents into detergent powders by spraying surfactants onto spray-dried builder beads.
• the specification refers to synthetic detergents such as nonionics, anionics, an cationics or combinations thereof as in general being liquid o liquefiable.
• mixtures of aqueous anionic and nonionic surfactants are viscous gels which can only be oversprayed onto particulate absorbents if they are heated to temperature, typically about 90°C, at which they become sufficiently mobile. Heating to this temperature is severely disadvantageous in factory practice.
• European Patent Application No. 88,612A discloses mobile liquid detergents containing not more than 8% water and not less than 90% active detergent, including an anionic surfactant, a nonionic polyether, and coconut or mono- ordiethanolamide. Substantial quantities of a third ingredien are required in order to obtain sufficiently mobile liquid products.
• U.S. Patent Nos. 4,862,632 and 4,923,636 (Blackburn et al.) and U.S. Patent No. 5,075,041 (E.F. Lutz) are related to producing selected combinations of surfactants.
• the instant invention addresses a critical area in the Blackburn patents mentioned above. Blackburn exemplifies water to LAS (C 10-13 ) mole ratios of 4.1 to 2.7. The principal difference of the instant invention is in producing specific (lower) water contents with lower water to anionic mole ratios to achieve superior chemical stability.
• HAM's High active mixtures which are completely free of water typically have higher viscosities than HAM's with ultra- low (1-5%) water.
• the instant invention produces a water content appropriate to maintain both higher stability and lower viscosity and to ensure that the appropriate phase is present in the surfactant combination.
• microstructure of selected combinations of anionic to nonionic HAMs was investigated to determine whether specific phase structures existed at conditions which favoured stability.
• FFTEM freeze- fracture TEM
• SAXS small-angle x-ray scattering
• This d spacing is dependent on the amount of water present and the temperature. The less water available, the less opportunity for the nonionic complex to catalyze the decomposition. Another consequence of reduced water is a phase change from lamellar to reverse micelle thus trapping the water in the micelle core and even further reducing the opportunity for the nonionic complex to catalyze degradation.
• liquid surfactant composition mobile at a temperature within the range of from 15°C to 80°C and consisting essentially of:
• anionic surfactant selected from a sodium and potassium salt of a primary alcohol sulphate and/or an alkyl benzene sulphate in an amount not exceeding 60% by weight
• the weight ratio of the anionic surfactant to the nonionic is from 1:4 to 2:1, preferably 1:4 to 1:1 and where the mole ratio of water to the anionic surfactant is about 0.05 to 2.3 and preferably 0.05 to 2.0. If the water content is too low, the viscosity becomes to high.
• the invention further provides for a process for stabilising the selected anionic to nonionic ratio HAMs by reducing the water content so that the mole ratio of water to anionic is less than about 2.3 and preferably less than about 2.0. Desirably the ratio is at least 0.05 and preferably 0.05 to 2.0.
• the mole ratio of water to PAS is about 0.05 to 2.0, especiall 0.05 to 1.0 and desirably 0.05 to 0.2.
• water is suitably present at a level of 0.2 to 7% and preferably to 5% by weight .
• the mole ratio of water to LAS is suitably about 0.1 to 2.3 and preferably 0.4 t 2.0. Desirably, in this case, water is present in an amount o 0.5 to 8%.
• a further process for the manufacture of a particulate detergent composition or a component therefor which comprises spraying onto a solid particulate absorbent material at a temperature within the range of from 15°C to 80° a mobile liquid surfactant composition having a ratio of anionic surfactant to nonionic of 1:4 to 2:1 and a mole ratio of water to anionic of 0.05 to 2.3 consisting essentially of:
• an anionic surfactant comprising a sodium or potassium salt of an alkyl benzene sulphate and/or a primary alcohol sulphate in an amount not exceeding 60% by weight.
• the major advantage is in lowering the water content in the HAM systems to a selected level.
• the phase structure of the HAM is altered and the water activity is reduced.
• PAS HAMs with 1:2 anionic/nonionic were of one phase: curved lamellar liquid crystals.
• the exception was PAS at 0.2 wt . % water and 22°C, which forms an unknown meso phase.
• LAS HAMs with 1:1 anionic:nonionic without high-temperature storage are lamellar liquid crystalline phases (L-alpha) .
• LAS HAMs with 1:2 anioic/nonionic are a mixture of two equilibrium phases, inverse micelles and flat lamellar liquid crystals at water levels of 0.7 to 7% water and from 22°C to 80°C.
• LAS 1:2 HAMs do not change their microstructure after prolonged storage at 80°C.
• the volume fraction of inverse micelles is expected to increase as the anionic:non ⁇ on ⁇ c ratio decreases.
• compositions according to the invention contain 20-60% anionic surfactant and 20-80% nonionic surfactant, and as little water as possible while still retaining the rheological advantages of some water.
• Compositions in which the ratio of anionic surfactant to nonionic surfactant is from 1:4 to 2:1 are of especial interest.
• the water present may come from many sources and indeed i often added to LAS acid is an amount of 0.3 to 3% to reduce degradation.
• Water is produced from the neutralisation reaction when the acid is neutralised with caustic. The amoun depends on the molecular weight of the acid since one mole of water is produced for one mole of neutralised acid.
• the alkali metal hydroxide used to neutralise the acid is typically added as a 50% solution. This excess water contributes most of the water to the mixture.
• the "natural" water content of a neutralised HAM containing LAS and/or PAS when expressed as the mole ratio of water to anionic, may vary from about 3.4 to 3.7 for molecular weights of the C e to C j. .. PAS acid of about 220 to 360 (Sodium salt 242 to 382) and from about 3.6 to 3.8 for molecular weights of the C 8 to C 16 LAS acid of about 263 to 403 (Sodium salt 285 to 425) .
• a typical "natural" water and reduced water content calculated for a 1:2 PAS:NI high active mixture follows in table 1 below.
• LAS anionic composition 333 MW of LAS acid in raw material 96.4% active 1.4% sulphuric acid 1.7% free oil (Inert) 0.5% water
• Nonionic composition assume 100% active
• the nonionic surfactant is preferably an ethoxylated or mixed ethoxy-propoxylated primary or secondary aliphatic alcohol. Most preferred are ethoxylated primary alcohols, especially C & _ C 15 primary alcohols ethoxylated with from 2 to 25 moles of ethylene oxide per mole of alcohol.
• the anionic surfactant component in the composition of the invention is a sodium or potassium salt of a primary alcohol or alkyl sulphate and/or an alkylbenzene sulphonate.
• Suitable alkyl sulphates are sodium C l 2 -C 15 alkyl sulphates although other alkyl sulphates outside this carbon chain length range and potassium alkyl sulphates may also be used.
• Especially suitable alkylbenzene sulphates include those having a C 10 to C 14 alkyl chain.
• the method of preparation of the liquid mixture of the invention is important. Simple admixture of normally 30% aqueous neutralised PAS paste or 50% LAS paste with liquid nonionic surfactant in the desired proportions will not give a mobile isotropic liquid but instead will result in a highly viscous gel which is difficult to handle and to atomise.
• liquid nonionic surfactant may be gradually added to an anionic surfactant paste (neuttral salt) which will typically have an active matter content of about 50% by weight.
• anionic surfactant paste neutral salt
• the resulting viscous mixture containing more than 10% water, is then heated optionally, under vacuum to a sufficiently high temperature for a sufficient period of time for the water content to fall below 10% by evaporation.
• the temperature must be carefully controlled to avoid decomposi ion.
• a clear mobile liquid is obtained and this remains clear and mobile when allowed to cool to ambient temperature.
• This HAM may then further subjected to heating and vacuum to lower the mole ratio of the water to anionic to typically 2.3 or less.
• anionic surfactant precursor acid may be mixed with nonionic surfactant, and the mixture treated with concentrated aqueous sodium hydroxide or potassium hydroxide to effect partial or complete neutralisation.
• Mixtures which are fluid at 20°C to 80°C and contains, depending on the ratio of anionic to nonionic about 3% to 10% by weight of water may be produced by this method.
• the mixtur is then further subjected to water emoval to about 0.2% to 8% so long as the mole ratio of water to anionic is 2.3 or less.
• alkylbenzene sulphonic acid may be in partially neutralised form if desired.
• the mixture of the invention if sufficiently mobile and stabl at ambient temperature, are useful in their own right as concentrated liquid detergents. These may, for example, be used as such or in diluted form as dishwashing liquids or laundry detergents.
• the final products of the invention are primarily concerned, however, with the preparation of granular detergent products b spraying the liquid mixtures of the invention onto absorbent granular base materials.
• the limits on stability are still strict but the limits on fluidity are a little less stringent in that compositions of the invention while they must be stable should also be sufficiently mobile a a temperature within the range of from 20°C to 80°C to be sprayable.
• the surfactant mixture of the invention may be sprayed onto a carrier material which is subsequently dry-mixed with other, necessary or desirable components of the final composition.
• the carrier material may itself be spray-dried: examples of suitable absorbent spray- dried inorganic carrier materials are sodium carbonate/sodium bicarbonate mixtures as described and claimed in GB No. 1,595,769; sodium carbonate/sodium silicate mixtures as described in GB No. 1,595,770; and, of especial interest, crystal growth modified sodium carbonate monohydrate and crystal growth modified Burkeite (sodium carbonate/sodium sulphate) as described in EP No. 221,776.
• Organic carrier materials are also suitable, such as citrates, polymers and the like.
• Crystal growth modified sodium carbonate monohydrate and Burkeit may be prepared by spray-drying an aqueous slurry comprising sodium carbonate, and optionally also comprising sodium sulphate in a weight ratio of sodium carbonate to sodium sulphate being at least 10% by weight based on the dried powder; an effective amount of a crystal growth modifier which is an organic material having at least three carboxyl groups in the molecule and optionally one or more anionic and/or nonionic detergent active compounds, one or more detergency builders and/or one or more further heat-insensitive detergent components; the crystal growth modifier being incorporated in the slurry not later than the sodium carbonate; whereby crystal growth-modified by sodium carbonate monohydrate and/or crystal growth modified Burkeite is or are fromed in the slurry.
• a crystal growth modifier which is an organic material having at least three carboxyl groups in the molecule and optionally one or more anionic and/or nonionic detergent active compounds, one or more detergency builders and/or one or more further heat-insensitive detergent
• the crystal growth modifier is a polycarboxylate as described in U.S. Patent Nos. 4,826,632 and 4,923,636.
• compositions of the invention may, if desired, be used in the compositions of the invention.
• spray-dried absorbent materials is appropriate for the manufacture of detergent powders with a range of bulk densities from low (300 g/1) to quite high (800 g/1) .
• th absorbent materials can be materials which also have a detergency building action, it is also possible to add detergency builders to the compositions, by including them in any crutcher slurry which is produced and spray-dried, or b adding them to the composition produced by the spray-drying step.
• detergency builders examples includesodium, tripoly , pyro- and orthophosphates, sodium aluminoscilicates includin zeolites, sodium carbonates sodium citrate and various organic detergency builders such as sodium nitrilotriacetate and 2 , 2 ' oxydisuccmates.
• detergency builders will be present in amounts of from 15 to 50% by weight of the final product, amounts of from 25 to 40% by weight being more general .
• Detergent powders according to the invention may contain other conventional ingredients added either via the slurry (if the absorbent is a spray-dried powder) or by simple mixing in accordance with their known properties.
• Such ingredients include enzymes, fluorescers, antideposition agents, bleaches, bleach activators, bleach stabilisers, lather suppressors, dyes and perfumes.
• ⁇ pH values of more than 2 in LAS/NI HAMs are indicative of instability. It is observed that lower water:anionic ratios provide enhanced stability.
• PAS and LAS HAMs maybe inherently unstable exhibit a characteristics downward pH shift upon storage at 50-85°C.
• PAS HAMs are stable only for days at elevated temperatures. If the pH drops below 7, decomposition is auto- catalytic and the PAS quickly decomposes into alcohol and acid rendering it useless as a surfactant. pH drift also occurs at lower storage temperatures albeit more slowly.
• LAS HAMs typically exhibit a downward drift in pH and levels of about pH 4 to 5.
• sample jars in the Example were not hermetically sealed to prevent pressure build-up and the oven humidity was not controlled, samples lost moisture during the study.
• Table 3 contains only intial PAS HAM moisure values and water/anionic mole ratios, since all PAS HAM's decomposed before the completion of the eight week study.
• the PAS HAM water/anionic mole ratios are initial values.
• PAS HAMs are much less stable than LAS HAM's because the PAS (not the nonionic) determines the stability.
• 80°C storage is a stringent test which provides trends which can be applied at lower (more realistic storage) temperatures e.g. ⁇ 60°C. Buffering only improves stability slightly; however, as shown in Table 3 reducing the water/anionic mole ratio to 0.09 improved stability significantly for a 1:2 (Lial 125) PAS/Neodol 25-7 HAM at 80°C.
• Table 4 contains both initial and average LAS HAM moisutre values and water/anionic mole ratios. Unexpectedly, a slight reduction in water content improves stability significantly without buffering. The improvement is most pronounced as LAS:Nonionic ratio decreases and as initial pH decreases.
• HAM odour improves significantly because other volatiles are removed during the water reduction process. For example, by reducing 1;2 LAS HAM water/anionic mole ratio fro its "natural" value of 3.4 to about 1.7 odour improved from a "3" to a "2" rating on a five-point subjective scale.
• a mobile liquid mixture suitable for spraying is prepared by admixing 5 parts by weight of a nonionic surfactant (C 12-15 alcohol 7EO) with 16 2/3 parts by weight of an aqueous sodium ⁇ i 2 ⁇ c _4- PAS paste (30% active matter) and heating the resultant mixture under vacuum until it has lost about 16 parts by weight of water.
• the resulting mobile liquid contains (by weight) 5% water, and has a water to anionic mole ratio of 1.9 47% primary alkyl sulphate and 47% nonionic surfactant.
• a LAS containing mixture is prepared by substituting the PAS paste for 10 parts by weight of an aqueous sodium (C 10 - 12 ) alkylbenzene sulphonate paste (50% active) The resultant mixture is heated under vacuum until it has lost about 4.5 parts water to provide a mobile liquid with about 5% water which is stable.
• aqueous crutcher slurry containing 46% by weight of water is spray-dried in a counter-current spray-drying tower to a base powder having a bulk density of 710 g/litre and a moisutre content of 15.8%.
• the formulation of the powder prepared is as follows:
• a mobile mixture of anionic and nonionic surfactant in accordance with the invention manufactured by mixing 3.8 parts of C 12 8 PAS acid with 6 parts of a C : _ 15 primary alcohol 7EO ethoxylate and neutralising the acid with caustic soda solution of 100°Tw is prepared. This mixture is then heated under vacuum until the water content is reduced to about 3%. The mole ratio of water to anionic is 1.4. This mixture is then sprayed onto the powder.
• the powder is dosed with heat-sensitive components such as oxygen bleaches, perfumes and enzymes in accordance with conventional practice to produce a finished powder having the following composition:
• the finished powder produced will have a bulk density of about 800 g/litre.
• the microstructures of 1:2 anionic:nonionic PAS HAMs were determined by FFTEM and SAXS before eight weeks of storage at 80°C with varying amounts of water. The microstructures were determined at both 21°C and 80°C. Samples for FFTEM were fast- frozen using a controlled environment vitrification chamber similar to the design of Bellare et al . (mentioned above) . Th chamber maintains equilibrium water content of samples prior t fast freezing by maintaining a saturated humid env ⁇ onment at a fixed temperature.
• SAXS data were collected at both room temperature and 80°C fro samples sealed in tubes. However, SAXS data were collected only from 1:2 HAMs.
• PAS 1:2 SAXS spectra of water-reduced (0.2 wt . % water) PAS 1:2 HAMs at 21°C and 80°C shows that PAS 1:2 at 0.2 wt % water and 22°C could be a mixture of liquid crystals and complex multiple L2 phases; peaks arise at 7.8, 5.2, 3.9 and 3.4 nm. In contrast, raising the temperature to 80°C results in a transition to an L-alpha (lamellar) phase, as indicated by a sharp peak at 3.5 nm. No micellar peak is evident.
• anionic:nonionic ratio falls from 1:2 to 1:4 they are believed to be L-alpha liquid crystals with an increasing function of reverse mecelles.
• Example 4 The procedure of Example 4 was repeated to determine the microstructures of 1:1 and 1:2 anionic:nonionic LAS HAMs by FFTEM and SAXS before and after eight weeks of storage at 80°C with varying amounts of water, at both 21°C and 80°C.
• the average spatial extent of the lamellae is about 200 nm for 0.7%, 1 micrometer for 6.0%, and several micrometers for 7.8%.
• LAS HAMs with 1:1 anionic:nonionic without h gh temperature storage are pure lamellar liquid crystalline phases (L-alpha) . It s believed that the loss in stability occurs for the same reasons described in Example 4.
• LAS HAMs with 1:2 anionic/nonionic are a mixture of two equilibrium phases, inverse micelles and flat lamellar liquid crystals. This was determined from 0.7-7.0 wt . % water and from 22-80°C. As the water decreases and the temperature increases, the mixtures become less lamellar and more reverse micellar. The volume fraction of inverse micelles is expected to increase as the anionic:nonionic ratio decreases.

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• 1995
  • 1995-11-22 AU AU43000/96A patent/AU4300096A/en not_active Abandoned
  • 1995-11-22 EP EP95941626A patent/EP0799295A1/de not_active Withdrawn
  • 1995-11-22 CN CN 95197609 patent/CN1175276A/zh active Pending
  • 1995-11-22 BR BR9510098A patent/BR9510098A/pt not_active Application Discontinuation
  • 1995-11-22 CA CA002208038A patent/CA2208038C/en not_active Expired - Fee Related
  • 1995-11-22 WO PCT/EP1995/004639 patent/WO1996019556A1/en not_active Application Discontinuation
  • 1995-12-20 TW TW84113654A patent/TW382025B/zh not_active IP Right Cessation
  • 1995-12-20 AR AR33471695A patent/AR000401A1/es unknown

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