Classifications

• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/16—Organic compounds
  • C11D3/20—Organic compounds containing oxygen
  • C11D3/2075—Carboxylic acids-salts thereof
  • C11D3/2086—Hydroxy carboxylic acids-salts thereof
• • 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
  • C11D3/2075—Carboxylic acids-salts thereof
  • C11D3/2079—Monocarboxylic acids-salts thereof
• • 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
  • C11D3/2075—Carboxylic acids-salts thereof
  • C11D3/2082—Polycarboxylic acids-salts thereof
• • 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
  • C11D3/43—Solvents

Definitions

• the present invention relates to improvements in general purpose cleaning compositions for household use.
• Powdered cleaning compositions consist mainly of builder or buffering salts such as phosphates, carbonates, silicates etc. Such compositions display good inorganic soil removal, but they can be deficient in cleaning ability on organic soils such as the calcium and/or magnesium salts of fatty acids and fatty/greasy soils typically found in the domestic environment. Such compositions generally form solutions buffered at an alkaline pH by the builder. It is generally believed that alkaline pH facilitates the detergency of free fatty acids by conversion of the fatty acids into the corresponding soap.
• Liquid cleaning compositions generally comprise an organic solvent and have the great advantage that they can be applied to hard surfaces in neat or concentrated form so that a relatively high level of surfactant material and organic solvent is directly delivered onto the soil.
• These liquid compositions are of particular utility in the cleaning of hard surfaces such as floors and walls and kitchen or bathroom surfaces as well as being useful in cleaning soft furnishings such as upholstery, carpets, curtains etc. Again, these compositions are generally buffered alkaline although neutral compositions are known and some acidic compositions have been marketed as specialist bathroom cleaners.
• compositions may comprise organic acids, such as citric, adipic or glutaric acids.
• the surfactants used in commercial general purpose cleaners include one or both of linear alkyl benzene sulphonates (ABS) and secondary alkane sulphonates (SAS) .
• ABS linear alkyl benzene sulphonates
• SAS secondary alkane sulphonates
• European Patent EP 0344847 discloses compositions comprising butoxy-propanol solvents in combination with up to 5%wt sodium linear C8- C18 alkyl benzene sulphonate.
• Mixtures of linear alkyl benzene sulphonates with alcohol ethoxylates and optionally small amounts of fatty soaps comprise the surfactant system used in a number of successful, liquid, alkaline, commercial products having an in-product pH of 8-11.
• Limescale largely consists of calcium and magnesium carbonates, which are present as the corresponding bi-carbonates at varying levels in natural waters and form the carbonate on crystallisation by disproportionation. It is well known that carbonates are soluble in acidic solutions. However, for the reasons given above, it is believed that acid compositions are less effective than alkaline compositions.
• compositions are less biodegradable and consequently less preferable environmentally than other surfactant systems.
• PAS primary alcohol sulphate
• Primary alcohol sulphate comprises a mixture of materials of the general formulation:
• R is a C 8 to C 18 primary alkyl group and X is a solubilising cation.
• Suitable cations include sodium, magnesium, potassium, ammonium, TEA and mixtures thereof.
• EP 125711 (Clarke: 1984) relates to GPC's containing nonionic, anionic (examples are Mg-PAS) and a partially esterified resin.
• GB-2160887 (Bristol Myers: 1984) relates to GPC's which comprise solvent, anionics including alkali metal, magnesium, ammonium and TEA-PAS salts and 0.005-3.0% of a nonionic including 75-100% on nonionic of a water insoluble nonionic.
• the sodium salt of the lauryl sulphate (Na-C 12 PAS) is the most preferred anionic surfactant.
• GB 2144763 (P&G: 1983) relates to cleaning composition in the form of a microemulsion, comprising at least 5% solvent and a magnesium salt.
• the preferred compositions comprise mixtures of nonionic surfactants, paraffin sulphonates, alkyl sulphates (PAS), ethoxylated phenols and ethoxylated alcohols.
• EP 107946 (P&G: 1982) relates to liquid detergent (dishwashing) compositions comprising 6-18% Mg-PAS, together with a water soluble C 13 -C 18 alkane or alkene sulphonate and a water soluble alkyl ether sulphate.
• ABS, SAS and PAS are very effective foaming surfactants. While the formation of foam is desirable with many personal washing products, such as shampoos and bar soaps, the presence of foam is often undesirable in fabric washing and surface cleaning operations, as foam can be difficult to remove after the cleaning operation. For this reason antifoams have been included in formulations.
• Calcium soaps i.e. the calcium salts of fatty acids are well known as an antifoaming component in -fabric washing compositions and in hard surface cleaning compositions.
• the hydrocarbon is broadly defined, as including straight or branched chain alkanes (liquid paraffin oils in 1:1 admixture with high melting paraffin waxes having a boiling point above 90 Celcius) , alkenes, alkylated benzene, condensed aromatics such as naphthalene and anthracene and their alkylated derivatives and alicyclic hydrocarbons, including terpenes and like compounds.
• Preferred hydrocarbons include those materials having a boiling point above 90 Celsius, such as the aforementioned mixtures of paraffin oils and waxes, dodecyl benzene and turpentine oil.
• EP 0080749 teaches the use of mono (two isoprene units) or sesqui- (three isoprene unit) terpenes in combination with both a specified solvent (2-(2-butoxy- ethoxy) ethanol: available in the marketplace as BUTYL CARBITOL [RTM] ) and 0.05-2%wt of one or more of the alkali, ammonium and alkanol-ammonium soaps of C13-C24 fatty acids as an antifoam system. In this citation, these three components are said to interact so as to have an antifoaming activity.
• the preferred terpenes as disclosed in this citation are the mono and bi-cyclic terpenes of the 'hydrocarbon class' of terpenes such as terpinenes, terpinolenes, limonenes, pinenes and the so-called 'orange' terpenes as obtained from the skins of oranges.
• Other terpenes including the terpene alcohols, aldehydes and ketones are less preferred.
• Terpenes and related compounds suffer from the general disadvantages that they are relatively expensive raw materials and odiferous compounds and generally lend a pine-like or lemon-like odour to products. It is desirable that the base formulation of cleaning compositions should have a low odour or be odour free. Moreover, terpenes may contain traces of so-called 'musk xylenes' and doubts have been raised as to the physiological acceptability of these materials.
• Products intended for use as bathroom cleaners should form a relatively stable, clinging foam in the initial stages of cleaning.
• This foam provides a visible indication of the parts of the surface to which the cleaner has been applied. More importantly, the foam clings to the surface and prevents run-off, thereby minimising the quantity of surfactant containing product which is required and consequently minimising both cost and the release of surfactants into the environment.
• an ideal household cleaning composition should form a relatively stable foam on application to a surface and rapidly de- foam when rinsed from the surface.
• Such compositions should not contain environmentally or physiologically unacceptable components and should not require the addition of special antifoaming components to the rinsing water.
• specialist cleaning compositions meeting many of these needs separately have been marketed or suggested in the literature a need exists for a general purpose cleaner which has the advantages of an acid cleaner against limescale but which is also effective against a wide range of soils.
• fatty acids have a foam- boosting effect in certain concentrated formulations and a foam depressing effect when said formulations are diluted with mildly alkaline water.
• these fatty acids are combined with polycarboxylic acids, solvents and surfactants, at acid pH, remarkably simple combinations of components produce compositions which show excellent cleaning on a wide range of soils and show excellent rinsing behaviour.
• the present invention subsists in an aqueous cleaning composition
• an aqueous cleaning composition comprising:
• a surfactant system comprising an anionic surfactant other than an alkali metal salt of a fatty acid
• composition having a pH of less than 6.
• the C10-18 fatty acids have a foam boosting effect in the compositions of the present invention. This is expressed as an improved 'cling' of the foam to sloping or vertical surfaces.
• the compositions according to the present invention are particularly well suited for use as hard surface cleaning compositions.
• Domestic water supplies generally contain some dissolved calcium, derived from minerals at typical levels ranging from 20-400 ppm. (2-40 degrees French) . Waters having higher levels of calcium are known but are relatively rare.
• Semi-polar solvents are essential components of the present invention. As will be shown hereinafter by way of example, the presence of solvent is believed to potentiate the foam boosting effect of fatty acid in acidic solution and potentiate the anti-foam effect of fatty acid in alkaline solution.
• Preferred solvents have a dielectric constant of from 5- 35.
• the solvent is selected from: propylene glycol mono n-butyl ether, dipropylene glycol mono n-butyl ether, propylene glycol mono t-butyl ether, dipropylene glycol mono t-butyl ether, diethylene glycol hexyl ether, ethyl acetate, ethanol, isopropyl alcohol, ethylene glycol monobutyl ether, di-ethylene glycol monobutyl ether and mixtures thereof.
• Preferred solvents are the glycol ether solvents and these are preferably selected from the group comprising propylene glycol mono n-butyl ether (available as 'Dowanol PnB' [RTM] ) and di-ethylene glycol monobutyl ether (available as 'Butyl Digol' [RTM] or 'Butyl Carbitol' [RTM] ) . These solvents are particularly preferred due to cost, availability and safety factors. We have determined that this selection of solvents gives enhanced cleaning performance as regards inks and dyestuffs and improved product stability as well as potentiating the antifoaming behaviour of the compositions on rinsing.
• Preferred ranges for the total surfactant:solvent ratios fall in the range 1:1 to 10:1, preferably 2:1 to 5:1.
• the narrower ratio range is preferred for reasons of cost and product stability.
• Typical solvent contents are l-30%wt of the composition, preferably 2-20% of the composition, in order to achieve an effective solvent concentration on dilution of the concentrates.
• Buffers are essential components of the compositions according to the present invention.
• the presence of a buffer is essential to ensure that the pH of the undiluted composition is maintained at an acidic pH, below the pK a of the fatty acid.
• the pH must not be so strongly buffered that excessive addition of water is required to raise the pH above the pK a of the fatty acid.
• the preferred buffer system comprises a polycarboxylic acid and a base selected from ammonium or alkali metal hydroxides and/or organic amines can also be used. Ammonium hydroxide is particularly preferred as it is believed to give enhanced calcium soap scum removal although sodium hydroxide also gives good results. Preferably, such a system will buffer the product at a pH 2-6.
• the buffer system is such that the pK a of the fatty is reached on addition of more than ten volumes of water on product.
• the alkalinity and hardness of the water added will have some effect on the quantity of water required to raise the pH above the pK a .
• the buffer system should be selected such that the pH is raised above the pK a of the fatty acid when less than 1000 volumes of water are added.
• a particularly preferred product pH range is pH 3.14-4.9, a pH around 4 is most preferred as certain enamels are sensitive to pH below 3 and products having a low pH can take excessive rinsing to neutralise the composition with waters of low alkalinity.
• the presence of polycarboxylic acids as salts in the formulation rather than as the acid form is believed to lead to a better foam so it is preferred that the pH of the composition should be above the lowest pKa of the polycarboxylic acid present.
• Citric acid the preferred polycarboxylic acid, has pKa's of
• weak sequesterants in the form of organic polycarboxylic acids are essential components of the compositions according to the present invention.
• the presence of these weak sequesterants improves cleaning performance. It is believed that these components sequester weakly bound calcium ions which are involved in the attachment of soil to surfaces and thereby facilitate the removal of these soils.
• sequesterants can also be present.
• sequesterants such as EDTA are less preferred for environmental reasons, as it has been suggested such poorly biodegradable sequesterants can solubilise heavy metals from river-bottom deposits.
• EDTA and other strong sequesterants have a tendency to complex with the calcium present in the domestic water and prevent the formation of the defoaming calcium soap mentioned above.
• the sequesterant is selected from, citric, adipic, succinic, malaeic, glutaric acids, mixtures thereof or salts thereof.
• Typical levels of sequesterant range from l-10%wt, preferably 3-6%wt on product.
• the sequesterant is citric acid or salts thereof.
• Citric acid is a weak sequesterant for calcium, available from renewable resources and is rapidly biodegradable.
• Citric acid is particularly preferred as both the sequesterant and a component of the buffering system, at preferable inclusion levels of 3-6%wt on product.
• C10-C18 fatty acids are essential components of the compositions according to the present invention.
• shorter chain fatty acids would not form sufficiently insoluble calcium soaps and longer chain fatty acids would be too insoluble in the composition to function as an antifoam component.
• these mid chain length fatty acids are commercially available at reasonable cost and are derived from renewable resources.
• the fatty acids may be linear or branched, saturated or unsaturated, but are preferably linear fatty acids obtained from nature.
• C12-C16 preferably C14
• average chain length linear fatty acids derivable from lauric acid oils such as coconut and palm-kernel fats
• Longer chain length soaps are less soluble in the absence of expensive hydrotropes or organic solvents.
• Typical levels of fatty acids range from 0.1-3% on product, with a range of 0.5-l%wt being particularly preferred.
• the pH of the composition is below the pKa of the fatty acid being employed.
• the pKa of a C12-C16 fatty acid will be close to 4.9, consequently the pH of the compositions will be below this figure.
• the pH of the composition will generally be in the range 3.14-4.9.
• At least one anionic surfactant other than soap is an essential component of compositions according to the present invention.
• the surfactant comprises one or more of the group comprising: primary and secondary alcohol sulphates, alcohol alkoxy sulphates, primary and secondary alkane sulphonates and alkyl aryl sulphonates.
• the products according to the present invention exhibit less effective cling.
• the ratio of fatty acid to anionic surfactant falls into the range 1:4 to 1:20, with particularly preferred around 1:5-1:10, expressed as wt% fatty acid to wt% anionic surfactant on product. This achieves a good balance between foaming and cleaning performance.
• the anionic surfactant is a primary alcohol sulphate (PAS) , a foaming, readily biodegradable, surfactant.
• PAS primary alcohol sulphate
• the preferred primary alcohol sulphate comprises a mixture of materials of the general formulation:
• R is a C 8 to C 18 primary alkyl group and X is a solubilising cation.
• Suitable cations include sodium, magnesium, potassium, ammonium and mixtures thereof.
• the Molar ratio of counterions for the PAS is such that around the ratio of Mg to other counterions does not exceed around 5:1. MgPAS to NaPAS ratios of more than 1:1 but less than 2:1 are preferred.
• PAS molecules are those with a major proportion of C 10 -C 14 alkyl residues.
• Suitable additional surfactants are selected from cationic, nonionic, amphoteric and zwitterionic surfactants as well as mixtures thereof.
• nonionic surfactants are alkoxylated alcohols and the preferred alkoxylated alcohols are selected from the group comprising ethoxylated alcohols of the general formula:
• R 1 -(OCH 2 CH 2 ) m -OH wherein R x is straight or branched, C 8 to C 18 alkyl or hydroxyalkyl and the average degree of ethoxylation m is 1-14, preferably 3-10 for good fatty soil detergency.
• the primary alcohol sulphates and alkoxylated alcohols are present in a ratio of from 3:1 to 1:1, with a ratio of around 2:1 being particularly preferred.
• compositions comprise 15-30% primary alcohol sulphate and 5-15% nonionic surfactant. These relatively high levels of PAS and nonionic surfactant are desirable in order to form concentrated compositions which can be transported more efficiently and require less packaging material.
• Preferred overall levels of surfactant comprise l-40%wt of the product, with levels of 2-10% being preferred for household use as non-concentrates. Surfactant levels of 20-40%, more preferably 25-35%, are preferred for concentrates although at the very highest surfactant levels additional antifoam components may be required Minors and Other Inessentials
• compositions of the invention can further comprise other minor components selected from the group comprising: perfumes, colours and dyes, hygiene agents, viscosity modifiers and mixtures thereof.
• perfumes, colours and dyes, hygiene agents, viscosity modifiers and mixtures thereof In certain embodiments of the invention it is useful to include further foam control agents in the formulation.
• the further foam control agents comprise hydrophobic oils. More preferably, the hydrophobic oil is a linear or branched chain hydrocarbon or silicone oil, even more preferably the hydrophobic oil is a paraffin.
• the hydrophobic oil is a paraffin with a 50%wt loss boiling point in the range 170-300, Celsius.
• the term 50% loss boiling point being intended to indicate that 50% of the weight of the paraffin can be distilled off at a temperature within this range.
• the limits of boiling points of paraffin suitable for use in the composition of the present invention lie between 171 and 250 Celsius.
• the isoparaffins i.e. branched chain paraffins, are particularly effective when compared with other hydrophobic oils such as n-decane and n-tetradecane.
• solubilised hydrophobic oil content of embodiments of the present invention is typically in the range 0.2-5wt%, preferably 1.0-2.0wt%. Where hydrophobic oil is present the preferred ' ratio of fatty acid to hydrophobic oil is in the range 0.5-1:1-0.5, preferably about 1:1. These proportions form a particularly effective antifoam system.
• compositions according to the present invention are homogeneous, more preferably translucent and most preferably transparent.
• Typical viscosities are 1-2000 mPas at a shear rate of 21 s-1 as measured at 25C.
• compositions of the present invention are provided in a package adapted to produce a spray of the product, preferably a spray of foam, although the possibility of other dosing and delivery systems is not intended to be excluded.
• surfactant comprising primary alcohol sulphate and preferably one or more nonionic surfactant wherein at least 50%wt of the surfactant present is primary alcohol sulphate, as principal surfactant
• a water soluble organic acid selected from citric, adipic, succinic, glutaric, maleic acids, salts thereof or mixtures thereof, as a calcium and magnesium sequesterant and buffering component, and, e) sufficient base to bring the pH of the composition into the range 3.14-4.9,
• Figure 1 shows the effect of formulation on the number of rinses required to reduce foam volume with waters of differing hardness.
• compositions were prepared according to Table 1 as below. All components were mixed at room temperature and filled into bottles equipped with trigger spray heads.
• the nonionic surfactant was DOBANOL 23-6.5 EO (RTM ex. SHELL), the PAS was DACPON-27L (RTM ex. DAC) .
• Butyl Carbitol is a trademark of Union Carbide.
• the fatty acid was PRIFAC 7901 (RTM ex. Uniche a) .
• Performance was evaluated by spraying the products onto a non-horizontal surface and rinsing with hard water (typically >26 French). 'Cling', was estimated by a panel of 20 trained technicians instructed to rate the foam cling in a blind test on a scale of 1-5 with 1 representing poor cling and 5 representing excellent cling.
• Example 1 is a commercially available product selected as a comparative example; the performance of this product was good.
• Figure 1 shows the effect of formulation on the number of rinses required to reduce foam volume with waters of differing hardness.
• Figure 2 shows the effect of pH on foam volume with waters of differing hardness.
• the pH mentioned is the pH of the liquor obtained during the rinsing cycles described above. It can be seen that as rinsing progresses, the pH of the liquor rises. It can be seen that for water containing an exceptionally high level of calcium the effect of the fatty acid was very marked. For more commonplace waters the foam volume fell rapidly once the pH had risen above 6.5 from the original product at 10% dilution pH of 4-5.
• the exemplified composition shows both improved foam cling and improved rinsing as compared with the composition of the prior art.
• Table 2 below gives data for compositions according to example 2 in which the average chain length of the fatty acid was varied. Data for the composition of Example 1, without fatty acid is given for comparative purposes. Cumulative foam volume, ('CFV') is measured in cubic centimetres for a standard initial volume and shaking protocol as described above with reference to examples 3- 8. The CFV indicates the total volume of foam generated in the rinsing process, using water of 26 French hardness Number of rinses required to eliminate the foam was determined as described above.
• Examples 24 and 26 show the effect of omitting the alkaline component (NaOH) of the buffer from the composition.
• the composition of Example 24 shows similar behaviour to the compositions of the invention in hard water, but is too acidic for use on some surfaces.
• Examples 25 and 26, with softer water, at 12 French hardness, show that embodiments of the invention (Example 25) exhibit acceptable rinsing whereas in the absence of the alkaline buffer component (Example 26) poor antifoaming is seen.
• Comparative examples 33 and 34 show that in the absence of anionic surfactant little or no foam is generated, allowing the product to run rapidly of sloping surfaces during cleaning operations.
• Examples 35 and 36 show the effect of the omission of the optional nonionic surfactant in the embodiments of the invention. From comparative example 35 it is seen that non-ionics have some foam suppressing activity although the rinsing time is increased by the presence of nonionics. From these results it is seen that while fatty acid and at least one other anionic are essential components nonionic is optional.
• Table 7 lists two comparative examples (Examples 38 and 39) of current, commercially available acidic bathroom cleaning compositions. These formulations were obtained by analysis.
• the organic acids were a mixture of succinic, glutaric, adipic and benzoic acids, totalling 6.2wt%.
• citric acid was used. It can be seen that the composition of example 38 differs from the present invention in that it does not employ the magnesium salt of PAS and no fatty acid or solvent is present.
• soiled tiles were prepared with a coating of a synthetic soap scum, fatty soil and kitchen soil. Each soil comprised a visible trace of carbon black as a visualising agent.
• the soap scum consisted essentially of calcium stearate, applied to a enamelled steel tile by spraying a suspension of calcium stearate in isopropyl alcohol. The tiles were baked at 180 Celcius for 30 minutes after application of the soil.
• the fatty soil consisted of a mixture of fatty acids and paraffin, applied to a ceramic tile by spraying the composition in petroleum ether.
• the kitchen soil consisted of a mixture of fats, fatty acids, paraffin and clay, applied to a ceramic tile by spraying the composition in petroleum ether.
• compositions of examples 37-39 were applied to each of the soiled tiles and left in contact with the tile for the periods specified in Table 7 under 'contact time'.
• the tile was then mechanically wiped with a clean damp cloth in a single pass at a fixed pressure.
• the residual soil was assessed visually on a six point scale of 0-5, where 0 indicates no soil removal and 5 indicates complete soil removal as indicated by the removal of the carbon black.
• compositions according to the present invention are equivalent to known compositions as regards the fatty soil removal but greatly improved as regards kitchen soil and especially soap scum removal.

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• 1993
  • 1993-10-09 ES ES93921928T patent/ES2097544T5/es not_active Expired - Lifetime
  • 1993-10-09 WO PCT/EP1993/002786 patent/WO1994009108A1/fr active IP Right Grant
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