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
  • C11D1/72—Ethers of polyoxyalkylene glycols

Definitions

• the present invention relates to cleaning compositions for hard surfaces. Specifically, compositions are described which are designed to give optimal performance in removing limescale stains and encrustations.
• Tap water always contains a certain amount of water hardness salts such as calcium carbonate which eventually deposit on surfaces which are often in contact with said water, resulting in an unaesthetic aspect of said surfaces. This limescale deposition phenomenon is even more acute in places where water is particularly hard.
• limescale deposits are removed by using a cleaning composition comprising an acid which "dissolves" limescale, typically phosphoric acid.
• an acid which "dissolves" limescale typically phosphoric acid.
• phosphoric acid has become subject to discussions, in relation to environmental questions. It is therefore an object of this invention to find an alternative to phosphoric acid in this particular context.
• compositions for the removal of limestone traces on laundry contain maleic acid and nonionic surfactants, as well as high amounts of phosphoric acid and urea.
• EP 200 776 describes a method to remove precipitates containing mainly calcium carbonate by using a mixture of a Lewis acid and a protonic acid, possibly maleic acid.
• J 61 28 3700 discloses detergent compositions for bathroom which comprises a maleic acid or anhydride-based polymer and a nonionic surfactant; these compositions also comprise cationic surfactants.
• EP 0 336 878 discloses an acidic cleaning composition comprising conventional surfactants and a dicarboxylic acid. Maleic acid is not mentioned.
• EP 0 141 395 discloses a composition suitable for removing limescale and encrustations from fabrics and washing machines. More particularly, EP 0 141 395 discloses liquid fabric conditioners comprising maleic acid, phosphoric acid, urea and nonionic surfactants.
• GB 2 106 927 discloses liquid thickened toilet bowl cleaners comprising a non volatile water soluble organic acid, a surfactant (e.g., a nonionic surfactant), and a cellulose ether, said composition having a pH of 2.2 to 3.5.
• the organic acids disclosed in said compositions include a fatty acid having from 2 to 3 carbon atoms, a dicarboxylic acid having from 3 to 8 carbon atoms, a hydroxy carboxylic acid containing 1 to 6 carbon atoms, 1 to 5 hydroxyl groups and 1 to 3 carboxyl groups, or mixtures thereof.
• Maleic acid is not mentioned amongst the suitable organic acids. Indeed, GB 2 106 927 expressly states that maleic acid was not screened.
• a surfactant e.g., nonionic surfactants
• organic acids having 2 to 10 carbon atoms
• aminoalkylenephosphonic acid phosphoric acid
• US 3 277 008 discloses a composition suitable for use with water to form an aqueous solution for descaling the internal metal surfaces of the jacket of glass-lined jacked equipment.
• This composition comprises a cleaning agent, an alpha-beta ethylenically unsaturated carboxylic acid like maleic acid and a corrosion inhibitor. No nonionic surfactants are disclosed therein.
• compositions according to the invention are aqueous compositions comprising from 1% to 15% by weight of the total composition of a nonionic surfactant or mixtures thereof and from 4% to 25 % by weight of the total composition of maleic acid; said compositions having a pH as is of from 1.0 to 4.0.
• the present invention is partly based on the finding that maleic acid possesses an unexpected superior limescale removing capacity, compared to phosphoric acid and compared to other dicarboxylic acids at equal levels.
• compositions according to the invention comprise from 4% to 25% by weight of the total composition of maleic acid. This percentage is calculated on the basis of the molecular weight of the acid form, but maleic anhydride is equally convenient for use in the compositions according to the present invention. Indeed, maleic anhydride is generally cheaper and it is transformed into the acid form when incorporated in an aqueous medium.
• the limescale removing capacity of the composition raises with the amount of maleic acid, up to a certain amount where a plateau in the limescale removing performance is reached. Accordingly, the compositions preferably comprise from 6 to 10% of maleic acid.
• compositions according to the invention have a pH as is of from 1.0 to 4.0.
• the limescale removing capacity of the composition is strongly dependent on its pH, and the lower the pH, the better the limescale removing performance; the pH of the composition also has an effect on the shine performance of the compositions, and the higher the pH, the better the shine; one therefore has to balance the pH so as to obtain the desired compromise between limescale removing performance and shine performance.
• the compositions according to the invention preferably have a pH as is in the range of from 1 to 2, preferably 1.2.
• compositions according to the present invention also comprise a nonionic surfactant system.
• typical limescale removing compositions do not perform optimally on bathroom type soils; this technical problem, which is not recognized in the art, is believed to be due to the soap scum which is present ,together with limescale, in bathroom type soils; indeed, soap scum has now been identified as having a detrimental effect on the limescale removing capacity of the composition.
• the compositions according to the invention comprise from 1% to 15% by weight of the total composition of a nonionic surfactant or mixtures thereof, preferably from 2% to 4% by weight of the total composition, and the compositions according to the present invention are preferably free of cationic and anionic surfactants.
• Nonionic surfactants are conventionally produced by condensing ethylene oxide with a hydrocarbon having a reactive hydrogen, e.g. a hydroxyl, carboxyl, or amido group, in the presence of an acidic or basic catalyst, and include compounds having the general formula RA(CH2CH2O)nH, wherein R represents the hydrophobic moiety, A represents the group carrying the reactive hydrogen atom, and n represents the average number of ethylene oxide moieties. R typically contains from 2 to 22 carbon atoms.
• Nonionic surfactants can also be formed by the condensation of propylene oxide with a lower molecular weight compound. n usually varies from 2 to 24.
• the hydrophobic moiety of the nonionic compound can be a primary or secondary, straight or branched alcohol having from about 8 to about 24 carbon atoms.
• Preferred nonionic surfactants for use in the compositions according to the invention are the condensation products of ethylene oxide with alcohols having a straight alkyl chain, having from 6 to 22 carbon atoms, wherein the degree of ethoxylation is from 5 to 12 Most preferred are C8-C12 ethoxylated alcohols with a degree of ethoxylation of 6; these surfactants are commercially available from Shell under the trade name Dobanol R 91-6. These nonionics are preferred because they have been found to allow the formulation of a stable product without requiring the addition of stabilizers or hydrotopes. When using other nonionics, it may be necessary to add hydrotopes such as cumene sulphonate or solvents such as butyldiglycolether
• compositions according to the invention may additionally comprise optional ingredients such as colorants, bactericides, perfumes, thickeners, and the like.
• the limescale removing (LSR) capacity of different solutions was measured by soaking a marble block of standardized size in these solutions during 30 minutes; marble blocks are chemically speaking very similar to lime scale, i.e. contain essentially calcium carbonate. Each marble block is weighed before and after the experiment, and the performance is expressed in grams of marble block "dissolved" during the 30 minutes.
• compositions A B C LSR/clean marble block: 0.88 0.89 0.78 LSR/ soap scum covered: 0.36 0.86 0.60
• NS stands for "not soluble” i.e. the tested acid is not soluble in the tested composition.

Landscapes

• 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)
• Detergent Compositions (AREA)
• Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)

Priority Applications (14)

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Publications (2)

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Citations (2)

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• 1991
  • 1991-01-22 ES ES91870011T patent/ES2108040T3/es not_active Expired - Lifetime
  • 1991-01-22 AT AT91870011T patent/ATE159542T1/de not_active IP Right Cessation
  • 1991-01-22 EP EP91870011A patent/EP0496188B1/en not_active Expired - Lifetime
  • 1991-01-22 DE DE69128025T patent/DE69128025T2/de not_active Expired - Lifetime
  • 1991-01-22 DK DK91870011.3T patent/DK0496188T3/da active
• 1992
  • 1992-01-17 TR TR92/0040A patent/TR25673A/xx unknown
  • 1992-01-21 CA CA002100096A patent/CA2100096C/en not_active Expired - Fee Related
  • 1992-01-21 WO PCT/US1992/000250 patent/WO1992013058A1/en active Application Filing
  • 1992-01-21 BR BR9205495A patent/BR9205495A/pt not_active Application Discontinuation
  • 1992-01-21 MX MX9200253A patent/MX9200253A/es not_active IP Right Cessation
  • 1992-01-21 JP JP50619292A patent/JP3217356B2/ja not_active Expired - Fee Related
  • 1992-01-22 AR AR92321662A patent/AR244786A1/es active
• 1997
  • 1997-10-23 GR GR970402530T patent/GR3025119T3/el unknown

Patent Citations (2)

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