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
  • C11D3/0005—Other compounding ingredients characterised by their effect
  • C11D3/0084—Antioxidants; Free-radical scavengers
• • 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
  • C11D1/126—Acylisethionates
• • 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
  • C11D10/00—Compositions of detergents, not provided for by one single preceding group
  • C11D10/04—Compositions of detergents, not provided for by one single preceding group based on mixtures of surface-active non-soap compounds and soap
  • C11D10/042—Compositions of detergents, not provided for by one single preceding group based on mixtures of surface-active non-soap compounds and soap based on anionic surface-active compounds and soap
• • 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
  • C11D17/006—Detergents in the form of bars or tablets containing mainly surfactants, but no builders, e.g. syndet bar
• • 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
  • C11D3/20—Organic compounds containing oxygen
  • C11D3/2003—Alcohols; Phenols
  • C11D3/2006—Monohydric alcohols
  • C11D3/2034—Monohydric alcohols aromatic

Definitions

• This invention relates to cleaning compositions containing fatty acyl isethionate as at least part of detergent active present.
• the compositions may in particular be in the form of bars for personal washing.
• Bars containing fatty acyl isethionate as the main detergent active have been marketed commercially for a number of years, and have achieved considerable acceptance in North America.
• Bars containing substantial amounts of isethionate have a distinctive odour, and it is known that the quality of the fatty acid used in production of the isethionate needs to be controlled in order to control the odour of the freshly-made product. Provided that this quality control is done, the fresh product can have an acceptable odour despite being subjected to high temperatures during the process of manufacture.
• the commercially made product with an acceptable odour when freshly made, has a shelf life which is generally satisfactory. Such a requirement must be the case for a product which has been accepted by consumers.
• the present invention resides in a finding that the shelf life of products containing fatty acyl isethionate can be improved by the incorporation into such products of small quantities of each of an antioxidant, a sequestrant for iron and a sequestrant for copper. It is essential to this invention that all three of these items are present.
• GB patent specification 1169551 (Unilever Limited) teaches the use of 0.02% EHDP and 0.02% EDTA by weight in soap bars.
• the specification suggests that fatty acyl isethionate can be present but does not take the matter further and in particular does not tackle the particular problem addressed in the present invention.
• the present invention provides a cleaning composition containing detergent active which includes at least some fatty acyl isethionate wherein the composition also contains at least 0.002% by weight of the composition of each of an antioxidant, a sequestering agent for iron, and a sequestering agent for copper.
• the invention provides a process of producing a cleaning composition which contains detergent active including at least some fatty acyl isethionate, which comprises incorporating into the composition at least 0.002% by weight of the composition of each of an antioxidant, a sequestering agent for iron and a sequestering agent for copper.
• a fatty acyl compound used to manufacture the isethionate is sparged with nitrogen or some other gas which does not react with it, prior to reaction to form the fatty acyl isethionate. It should then be maintained under an atmosphere of such gas until the isethionate formation step has been carried out. Accordingly a preferred process includes flushing a fatty acyl-containing precursor under an atmosphere of such gas.
• a preferred composition of this invention has its fatty acyl isethionate made in this way.
• Sparging with nitrogen will generally consist in bubbling the nitrogen through the fatty acyl-containing precursor compound while the latter is in a liquid form.
• the fatty acyl compound normally used is coconut fatty acid.
• the antioxidant used should be a compound able to suppress reactions proceeding via a free radical mechanism, and will generally be a free radical scavenging agent. Many such compounds are available.
• a compound is chosen which is able to survive the conditions under which a fatty acyl-containing precursor compound is reacted to form fatty acyl isethionate, and is added to the precursor compound before that reaction. Notably it may be added to coconut fatty acid as the precursor compound.
• the antioxidant is added after the fatty acyl isethionate has been formed and any other high temperature steps have been carried out. Suitably it is incorporated in the composition and maintained at a temperature below 170°C.
• a preferred antioxidant is 2,6-di-t-butyl-4-­methylphenol referred to hereinafter as BHT.
• a preferred level of addition of this compound is 200 ppm (0.02% by weight) based on the fatty acyl-containing precursor.
• a preferred sequestering agent for copper is ethylene diamine tetra acetic acid (EDTA) or a soluble salt thereof such as its tetra sodium salt or mixtures thereof.
• EDTA ethylene diamine tetra acetic acid
• Such agents are known to enhance the activity of iron in accelerating autoxidation, but can be used successfully provided there is a satisfactory sequestering agent for iron present. The two sequestering agents are then acting synergistically.
• the preferred sequestering agent for iron is 1-­hydroxyethane-1,1-diphosphonic acid (EHDP) or a soluble salt thereof or mixtures thereof. This sequestering agent can be used successfully even when the cleaning composition is superfatted. If the composition does not contain free fatty acid then an alternative possibility for the sequestering agent for iron is magnesium trisilicate.
• sequestering agents will generally be added after the fatty acyl isethionate has been formed and any other high temperature processing steps have been carried out.
• the sequestering agents are incorporated in the composition and maintained at a temperature below 170°C.
• the present process includes preparing the fatty acyl isethionate from isethionate and free fatty acid and flashcooling the product, and thereafter adding sequestering agents and also preferably the antioxidant.
• the quantity of the antioxidant, and of each sequestering agent should be sufficient to be effective. As indicated above, the amount should be at least 0.002% by weight of the composition and it is preferred to use a greater amount so that the composition contains at least 0.005% or at least 0.01% of each sequestering agent.
• the stoichiometric equivalent of 0.02% tetrasodium EDTA is 33 ppm copper.
• the stoichiometric equivalent of 0.02% EHDP (as pure acid) is 54 ppm iron. These quantities are well above the amounts of contaminating copper and iron which we have been able to detect in fatty acyl isethionate-containing bars as currently marketed.
• the total quantity of antioxidant plus sequestering agents will normally be below 1% by weight of the composition and indeed normally less than 0.1% by weight.
• Fatty acyl isethionates normally used in cleaning compositions have 8 to 18 carbon atoms in the fatty acyl group. Particularly preferred is coconut fatty acyl.
• the coconut fatty acyl may have been hardened, that is to say the amount of olefinic unsaturation reduced, in well known manner.
• the detergent actives present in a cleaning composition bar may consist exclusively or substantially exclusively of fatty acyl isethionate and soap. For example the amount of any other detergent active may be less than 2% of all detergent active present.
• Weight ratios of soap to fatty acyl isethionate may range from 10:90 to 95:5, preferably 15:85 to 60:40, and may be in the range 10:90 to 35:65 or 25:75.
• fatty acyl isethionate may provide at least 40%, preferably from 48%, up to 53% by weight of the composition.
• acyl isethionate and soap are not the only detergent actives present they may nevertheless constitute most of the detergent active present, e.g. more than three quarters of it with the weight ratio of soap to acyl isethionate still being within the range as indicated above.
• This invention is particularly applicable when fatty acyl isethionate constitutes at least the majority of detergent active present.
• a superfatted composition may contain more than 5% free fatty acid.
• the amount of superfatting acid may be more than equivalent to the amount of soap, so that soap is converted into its acid form to a substantial degree.
• the soap used may contain some additive to prevent deterioration of its own odour, but of course the amount will be diluted on mixing with fatty acyl isethionate. Generally a separate addition of the antioxidant and sequestrants of this invention will be required.
• the present invention may in particular be applied when the fatty acyl isethionate has been prepared by reaction of C8-C18 fatty acyl compound, usually the fatty acid itself with an isethionate at temperatures in excess of 100°C.
• BHT can be added to individual batches of coconut fatty acid and allowed to mix into the acid as that acid is sparged with nitrogen.
• EDTA and EHDP can conveniently be carried out by periodically dosing a small quantity of each of these materials into a tank where the fatty acyl isethionate is mixed with other ingredients of a cleaning composition. Both materials can be added in the form of aqueous solution and since the amounts which are added are small the increased water content of the composition is not significant.
• the two sequestering agents need to be added to the fatty acyl isethionate through separate pipework because if solutions of them are allowed to mix together before mixing with other material, there is a tendency for solids to crystallise out from the mixed solution.
• composition suitably admixed with for example soap and any other conventional additive e.g. dye, perfume, free fatty acid, sodium isethionate is suitably worked and formed into for example bars.
• any other conventional additive e.g. dye, perfume, free fatty acid, sodium isethionate is suitably worked and formed into for example bars.
• coconut fatty acid was reacted to form sodium fatty isethionate by the process described in US patent specification No. 3320292.
• the process comprises reacting a concentrated solution of sodium isethionate with coconut fatty acid in the presence of zinc oxide acting as catalyst.
• the reaction mixture is maintained at a temperature of about 232°C under a nitrogen blanket in order to remove water and allow the reaction to proceed.
• the resulting product is stripped to remove residual free coconut fatty acid.
• Stearic acid can be added at this stage in order to retain fluidity.
• the stripped product is then flash cooled, suitably by admixing with for example sodium isethionate solution.
• Other ingredients, in particular soap can then be admixed. For bars the mixture can then be rolled, milled, plodded and stamped.
• coconut fatty acid was reacted to form sodium fatty isethionate by the process of patent specification US 3320292.
• the process was carried out in slightly different ways to provide experimental and control products.
• the coconut fatty acid was sparged with nitrogen before reaction and the sparged material thereafter kept under a nitrogen atmosphere throughout all the reaction process steps carried out at elevated temperatures.
• BHT was included in the coconut fatty acid used for the experimental material, so as to provide 200 ppm BHT in the fatty acid. After flashcooling tetrasodium EDTA and EHDP were added to the experimental material to provide 0.02% by weight of each in the mixture.
• control material was prepared in the same way from the same batch of fatty acid but without nitrogen sparging, and without the additions of BHT, EDTA salt and EHDP.
• the experimental and control product materials were both processed into unperfumed and perfumed bars which were subjected to storage tests.
• the tester was provided with reference samples which were stored under refrigerated conditions so that these reference samples should undergo minimal change in odour. Even so, it should be appreciated that any ratings of 1, 2 or 3 are not truly absolute but rather are comparative between the experimental and control materials at the time of the test.
• Example 1 The preparation of sodium fatty acyl isethionate, processing of the product into bars and storage testing of those bars was carried out in the same way as for Example 1.
• the control bars are prepared without nitrogen sparging and without any BHT, EDTA or EHDP.
• a first experimental material was prepared while employing nitrogen sparging and adding the BHT to the coconut fatty acid.
• a second experimental material was also prepared while employing nitrogen sparging and the addition of BHT to the fatty acid before reaction: additionally tetra sodium EDTA and EHDP were added to this second experimental material after the reaction had been carried out.
• the products were prepared from the same coconut and stearic fatty acid production (ex Emery Chemicals Toronto) in order to ensure equivalence in the initial odour and chemical composition of the raw materials. All batches were produced with nitrogen sparging during the heat-up and reaction stages and during the stripping and flash cooling stages.
• the chromatographs for the control (ie unpreserved) product E indicate significant peaks of low molecular weight aldehydes and hydrocarbons, which are attributable to the result of oxidative degeneration (ie autoxidation) of unsaturated fatty acids.
• the two principal contributors to the malodour are isopentanal/pentanal and hexanal.
• sample C is less stable than sample D.
• sample D is less stable than sample D.
• the most stable product was that which was prepared with Na4EDTA, EHDP and BHT added after flash cooling as virtually all the identifiable low molecular weight aldehydes and hydrocarbons were eliminated.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Emergency Medicine (AREA)
• Biochemistry (AREA)
• Detergent Compositions (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Publications (3)

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Family Applications (1)

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Cited By (5)

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Citations (4)

• 1986
  • 1986-06-13 GB GB868614462A patent/GB8614462D0/en active Pending
• 1987
  • 1987-06-08 CA CA000539133A patent/CA1311399C/en not_active Expired - Fee Related
  • 1987-06-11 ES ES87305170T patent/ES2054671T3/es not_active Expired - Lifetime
  • 1987-06-11 EP EP19870305170 patent/EP0249474B1/de not_active Revoked
  • 1987-06-11 DE DE19873786113 patent/DE3786113T2/de not_active Revoked

Patent Citations (4)

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