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
  • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
  • C11D7/22—Organic compounds
  • C11D7/32—Organic compounds containing nitrogen
  • C11D7/3272—Urea, guanidine or derivatives 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
  • C11D3/37—Polymers
  • C11D3/3703—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • C11D3/3723—Polyamines or polyalkyleneimines

Definitions

• the present invention relates to the cleaning of equipment of amino resins. More precisely, the invention concerns the use of polyethylene imine or imines for ⁇ cleaning equipment of amino resins.
• urea glues In the woodworking industry, large amounts cf a ino- resin-based glues are used for making e.g. furniture, parquet floors, laminates and particle boards. These glues are based on formaldehyde and amino-containing compounds, 0 such as urea, melamine and benzoguanamine. The urea-formal ⁇ dehyde resins (commonly referred to as urea glues) are the most common.
• the glues are applied by means cf different; sorts of glue spreading equipment, such as roller spreaders and ribbon spreaders, or by spraying. Further, amino resms 5 are used also in other fields, e.g. in lacquers and paper additives.
• the cleaning problems are also linked with the waste disposal of amino-resin residues.
• Acid curing yields a hard, essentially insoluble ammo elastic which has to be treated as solid waste wmcr- releases formaldehyde.
• the combustion of wash water essen ⁇ tially requires that the resin residues are readily dis ⁇ persed in water to obtain a manageable dispersion. Normal ⁇ ly, it is not allowed to dump the resin residues directly in the municipal sewage system. Dumping requires that the resin concentration be brought to an acceptably low level by dilution.
• DE 39 01 328 discloses a washing solution for clean ⁇ ing containers and glue spreading equipment of amino-resin glue.
• the washing solution is made up of five different components, inter alia two different polymer ingredients. To achieve satisfactory washability, a fairly complex solution is required.
• One object of the present invention is, therefore, to solve the cleaning problems with regard to amino resins in a simple and rational manner.
• Another object of the inven ⁇ tion is to ensure acceptable handling of the waste resul ⁇ ting from the cleaning.
• the objects of the present invention are achieved by the use of polyethy ⁇ lene imine or imines for cleaning equipment of amino resins. It has surprisingly been found that, when the polyethylene imine or imines are applied to the amino- resin-smeared equipment, the resin will be effectively washed away and dispersed in the aqueous phase. The resul ⁇ ting dispersion may then without problems be diluted with large amounts of water.
• Polyethylene imines make up a family of water-sol ⁇ uble, hydrophilic polyamines of varying molecular weight. They act as weak bases and have a cationic nature (at pH ⁇ 10.5) . Generally, polyethylene imines are heavily branch ⁇ ed and contain primary, secondary as well as tertiary amine groups. Polyethylene imines are commercially avail ⁇ able at molecular weights ranging from about 300 g/mole to more than 6 x 10 g/mole. It is common to use polymers of comparatively high molecular weight (MW >10,000 g/mole). For instance, polyethylene imines are widely used for improving the retention in papermaking (i.e. as retention agents). Polyethylene imines may then be used for binding fibres (fines) and colloidal particles, so that these become effective in the paper by improved dewatering. Otherwise, the fines have a tendency to circulate in the system.
• polyethylene imine may be used in washing compositions for cleaning metal surfaces of metal oxides and the like, as disclosed e.g. in US 3,627,687 and US 3,754,990.
• the excellent dispersing and washing effect of poly ⁇ ethylene imine or imines on amino resins can be explained by the fact that the cationic groups electrostatically bind to anionic or polar groups on amino-resin oligomers and/or amino-resin crystals in the resin or .the glue.
• the high density of cationic groups on the branched polymer imparts a hydrophilic nature to the formed aggregates, which thus become readily dispersible. This is combined with an osmotic effect (steric stabilisation), keeping the aggregates apart in the solution.
• the washing method of the invention also results in improved waste disposal, which constitutes a preferred embodiment of the invention.
• a method has been developed, in which the dispersed resin, after the cleaning, is further diluted with water under agitation in a separate tank until the concentration of amino resin has reached an acceptably low level.
• an acceptably low level' is here meant such a low concentration of amino resin in the wash water that the latter may be discharged into the public sewage system. If this method is to work, the wash water has to be a readily diluted dispersion, which is achieved by the proposed washing method.
• the polyethylene imines that can be used for cleaning are water-soluble polyethylene imines having a molecular weight ranging from about 200 g/mole to about 10 7 g/mole, preferably from about 10 4 g/mole to about 5 x 10 6 g/mole, and most preferred from about 10 5 g/mole to about 1.5 x 10° g/mole.
• Such polyethylene imines are well-known as well as commercially available.
• the amount of polyethylene imine to be added to give a satisfactory washing effect may vary within comparative ⁇ ly wide limits. However, should the amount of polyethylene imine added be too small, the amino resin may be insuffi- ciently dispersed, which would involve the risk of gel formation. An excessive amount of polyethylene imine may, on the other hand, result in considerable foaming. Gener ⁇ ally, the amount of polyethylene imine added should suitab ⁇ ly lie within a range of from about 0.005% by weight to about 10% by weight of pure polyethylene amine, based on the amount of resin to be washed away, preferably within a range of from about 0.1% by weight to about 3% by weight, and most preferred within a range of from about 0.2% by weight to about 0.6% by weight.
• the polyethylene imine or imines may be used un ⁇ diluted in the cleaning operation.
• the polyethylene imines are, however, preferably used in the form of a water-based washing solution.
• concentration of the water-based washing solution is not critical. A suitable concentration may range from about 10% by weight to about 30% by weight of polyethylene imine. However, use may very well be made of solutions having much higher concentrations. Solutions having low concentrations ( ⁇ 5% by weight) are less suit ⁇ able, since they involve considerable amounts of water for obtaining an effective amount of polyethylene imine.
• the solution employed is prepared by dissolving the polyethy ⁇ lene imine in water.
• the polyethylene imine solution can be used for cleaning all sorts of equipment that has come into contact with amino resins. .Preferably, the washing solution is used for cleaning different sorts of glue spreading equip- ment with respect to amino-resin glues.
• glues are, for instance, made up of reaction products of formaldehyde and urea, melamine and bezoguanamine or mixtures thereof.
• the washing of the equipment is performed in conven- tional manner.
• the washing solution consisted of polyethylene imine SK (BASF) (20% active content; molecular weight: 1.3 x 10 6 g/mole (M m ) ) .
• the solution was poured out along the entire width of the roller in a thin strand, and the glue (urea-formaldehyde resin glue) and the washing solution were mixed for 0.5-1 min by rotating the rollers.
• the concentration of the washing solution corresponded to an amount of added poly- ethylene imine of about 1-3% by weight of the amount of glue. This yielded a fine milky white dispersion readily diluted with large amounts of water.

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)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Detergent Compositions (AREA)
• Macromolecular Compounds Obtained By Forming Nitrogen-Containing Linkages In General (AREA)

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• 1992
  • 1992-01-30 SE SE9200255A patent/SE500522C2/sv not_active IP Right Cessation
• 1993
  • 1993-01-27 EP EP93903372A patent/EP0624187A1/en not_active Ceased
  • 1993-01-27 WO PCT/SE1993/000056 patent/WO1993015177A1/en not_active Application Discontinuation
• 1994
  • 1994-07-15 FI FI943378A patent/FI943378A/sv unknown
  • 1994-07-29 NO NO942821A patent/NO304837B1/no not_active IP Right Cessation

Non-Patent Citations (1)

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