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
  • C11D3/2082—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
  • 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
  • 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
  • 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
  • C11D1/143—Sulfonic 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
  • C11D1/66—Non-ionic compounds
  • C11D1/72—Ethers of polyoxyalkylene glycols

Definitions

• the present invention relates to compositions for the removal of limescale.
• Limescale mainly comprises calcium and magnesium carbonates, and can contain lesser amounts of soap scum, protein, particulates and other soils. Limescale is formed on evaporation of water containing said soils. While the deposit formed by evaporation is initially paste-like, it hardens with time to form a recalcitrant deposit.
• Conventional cleaning compositions are generally buffered at alkaline pH so as to attack fatty soils. Limescale is resistant to the action of alkali and specialist cleaning compositions, of acid pH, are used to remove it.
• a plurality of limescale removing compositions are disclosed in EP 0253676. These compositions are thickened by means of an amine or an amine oxide and comprise an acid which may be organic or inorganic.
• Limescale removing compositions of maleic acid in combination with nonionic surfactants are known. In the absence of nonionic surfactants cleaning efficiency is greatly reduced.
• Maleic acid is known to be a particularly effective limescale remover and is less prone to attack surfaces than the inorganic acids.
• EP 0496188 (P&G) relates to compositions with 1-15% nonionic and 4-25% of maleic acid, having a pH of 1-4. Preferred compositions are formulated at pH 1-4 and comprise maleic and nonionic at specified levels but which are substantially free of both ionic detergents and phosphoric acid.
• EP 0496188 teaches that compositions should be 'preferably free of anionic and cationic surfactants'.
• EP 0496188 also teaches that unperfumed compositions, which are free of anionic surfactant, can be made with both maleic and citric acid present (see examples VII-XI thereof) but says nothing about the stability of these compositions.
• Maleic acid is produced from petrochemical sources and potentially oxidises to produce rancid odours.
• Maleic acid is a relatively toxic material and is moderately expensive.
• Other organic acids, such as citric and lactic acids are available from renewable resources, are less toxic and less prone to oxidation.
• compositions comprising citric acid together with nonionic surfactants are unstable.
• the present invention provides a stable, limescale-removing compositions of pH 1-4, comprising maleic acid, a nonionic surfactant and an alpha-hydroxy carboxylic acid CHARACTERISED IN THAT the composition further comprises a perfume and an anionic surfactant wherein the ratio of the anionic surfactant to the nonionic surfactant is in the range 3:1-1:1.
• alpha-hydroxy carboxylic acid is less toxic and less prone to decomposition than an equivalent amount of maleic acid, i.e. an amount which provides comparable limescale-removing performance.
• the alpha-hydroxy carboxylic acid interacts with the nonionic surfactant to destabilise the product in the absence of the anionic surfactant.
• compositions comprise a fragrance.
• a fragrance is important both to meet consumer expectations and to mask any off odours resulting from decomposition of the organic acids. It is believed that the presence of the anionic detergent is essential in order that the perfume can be solubilised in the composition.
• Typical levels of maleic acid in the product range from 2-6%wt. It is preferable that the level of maleic acid is below 4%wt so as reduce toxicity and prevent the development of excessive off odours. The most preferred level of maleic acid falls into the range more than 3.0%wt and less than 4.0%wt.
• Preferred alpha-hydroxy carboxylic acids are lactic acid, glycolic acid and citric acid.
• Polycarboxylic acids, particularly citric acid is the most preferred for reasons of cost, ease of availability and weight-effectiveness.
• the preferred of citric acid are 2.5-10wt%, most preferably 2.5-7.5wt%.
• alpha-hydroxy carboxylic acid should be present in weight excess relative to the maleic acid.
• Ratio of alpha-hydroxy carboxylic acid to maleic acid is preferably in the range 1-2:1.
• nonionic surfactants should not include any significant amounts of amine oxide.
• the preferred nonionic surfactants are alkoxylated alcohols.
• 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 1 is straight or branched, C 8 to C 18 alkyl or hydroxyalkyl and m is, on average, 1-14.
• the alkyl chain length is C 8 -C 11 . It is believed that this reduces the strength of the interaction with the alpha-hydroxy carboxylic acid.
• the preferred average degree of ethoxylation m is 6-9 for good fatty soil detergency and high solubility in the composition.
• the nonionic surfactant should have a HLB in the range 12-16.
• Preferred levels of nonionic surfactant range from 0.5-7%wt, more preferably 0.75-3%wt.
• the anionic 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 preferred anionic surfactants are the secondary alkane sulphonates. Most preferably the secondary alkane sulphonate is a C 12 -C 18 average chain length secondary alkane sulphonate.
• Preferred levels of anionic surfactant range from 1-10%wt, more preferably 1-6%wt. It is also preferable that the alpha-hydroxy carboxylic acid is present in weight excess over the total surfactant content.
• a thickener when present are xanthan gums.
• Preferred xanthan gums are the Kelzan (RTM) series (available from Kelco Corp). Typical levels of xanthan gum range from 0.05-lwt%.
• the resulting viscosity of the composition, as measured on a Haake RV2 rotoviscometer (RTM) is preferably in the range 10-200 mPas at 20 reciprocal seconds shear and 25 Celcius, using an MV1 bob. More preferably the thickened compositions have a viscosity of 10-100 mPas under the conditions mentioned above.
• Preferred levels of perfume range from 0.1-1%wt. Acid stable perfumes are available from a variety of sources including the Quest company.
• compositions of the present invention include opacifiers, colours, preservatives and fluorescers.
• Preferred formulations comprise: a) 2-4%wt maleic acid, b) 0.75-3%wt ethoxylated alcohol of HLB 12-16 c) 1-6%wt secondary alkane sulphonate, d) 2.5-7.5%wt citric acid, and, e) 0.1-0.5%wt perfume, said compositions having a pH of 1-3 and a viscosity of 3-7 mPas as measured on a Haake RV2 rotoviscometer (RTM) at 20 reciprocal seconds shear and 25 Celcius, using an MV1 bob.
• RTM Haake RV2 rotoviscometer
• compositions were prepared by:

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

Applications Claiming Priority (5)

Publications (2)

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Family Applications (1)

Country Status (7)

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• 1994
  • 1994-11-12 DE DE69409254T patent/DE69409254T2/de not_active Expired - Fee Related
  • 1994-11-12 AU AU81436/94A patent/AU678313B2/en not_active Ceased
  • 1994-11-12 EP EP95900745A patent/EP0730628B1/en not_active Expired - Lifetime
  • 1994-11-12 BR BR9408132A patent/BR9408132A/pt not_active IP Right Cessation
  • 1994-11-12 ES ES95900745T patent/ES2113723T3/es not_active Expired - Lifetime
  • 1994-11-12 WO PCT/EP1994/003790 patent/WO1995014756A1/en active IP Right Grant
  • 1994-11-12 CA CA 2175677 patent/CA2175677A1/en not_active Abandoned

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