Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
  • C08G18/78—Nitrogen
  • C08G18/79—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
  • C09D175/04—Polyurethanes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/0804—Manufacture of polymers containing ionic or ionogenic groups
  • C08G18/0819—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups
  • C08G18/0823—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups containing carboxylate salt groups or groups forming them
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
  • C08G18/78—Nitrogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L75/00—Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/20—Diluents or solvents
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/60—Additives non-macromolecular
  • C09D7/63—Additives non-macromolecular organic
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/65—Additives macromolecular

Definitions

• This invention relates generally to two component aqueous polyurethane dispersions that"have a reduced solvent content. More particularly, this invention relates to two component aqueous polyurethane dispersions, containing low viscosity polyisocyanates, that can be cured at ambient temperature, or, if desired, at higher temperature.
• the coatings prepared therefrom have improved hardness, gloss and solvent resistance compared to conventional aqueous polyurethane dispersions.
• aqueous polyurethane dispersions are well known and are used in the production of a variety of useful polyurethane products, including, for example, coatings, adhesives, sealants, and the like.
• Such dispersions are typically produced by dispersing a water-dispersable, isocyanate- r terminated polyurethane prepolymer in an aqueous medium together with an active hydrogen containing chain-extender.
• the prepolymers used in the preparation of these one component dispersions are generally substantially linear, that is to say difunctional, and are typically obtained by reacting an excess of a diisocyanate with an isocyanate-reactive component comprising a polymeric diol in the presence of a reactive compound, for example a diol, containing an ionic or non-ionic hydrophilic group or site.
• the one component water based polyurethane dispersions have reduced amounts of organic solvent relative to comparable solvent-based coating compositions, for many applications, they do not exhibit similar coating performance similar to solvent based coating compositions, especially with respect to the properties of gloss, hardness and solvent resistance. This difference is mainly attributable to the lack of chemical crosslinking during the formation of films using the one component, water based systems.
• Solvent based two component polyurethane compositions achieve the desired chemical crosslinking by using multifunctional polyisocyanates, such as those containing isocyanurate groups.
• Multi-functional polyisocyanates have high viscosities and are hydrophobic in nature. They cannot be dispersed in aqueous dispersions, and hence are unsuitable for water based polyurethane compositions.
• i based polyurethane coating compositions prepared using water dispersable polyisocyanates, are a shorter pot life, a higher amount of needed isocyanate crosslinker, and a lower gloss (if the amount of co-solvent is not increased) than otherwise might be desired.
• the present invention relates to a two-component aqueous polyurethane coating composition that is curable at 25 degrees Centigrade (or at a higher temperature if desired) into a coating exhibiting enhanced hardness, gloss, and solvent resistance, said coating composition comprising:
• a polyisocyanate which is dispersible in an aqueous polymer resin dispersion has an average functionality of at least 2.0 and contains:
• A 25% to 95% by weight of a polyisocyanate adduct selected from the group consisting of cyclodimers or allophanates of 3,3,5- trimethylhexamethylene diisocyanate, 2- methylhexamethylene diisocyanate, isophorone diisocyanate, 1,4-tetramethylene diisocyanate, 1,6- hexamethylene diisocyanate, and combinations thereof, and
• component (C) 0% to 30% (preferably 0% to 20%) by weight of an organic solvent that is inert to isocyanate,- and, (II) an isocyanate reactive hydroxyl-terminated, water dispersable polymer resin having a hydroxyl number of between 10 and 450 (preferably between 28 and 350) , with the proviso that if component (B) cons ists essentially of cyclotrimerized isophorone diisocyanate, then component (C) is present in an amount of at least 10% by weight, based upon the weight of said coating composition.
• the present invention relates to a process for preparing the above-described coating composition, and to a coated substrate containing a coating prepared from the coating composition.
• the process comprises contacting component (I) and component (II) of said two- component aqueous polyurethane coating composition to provide a mixture, and admixing said mixture to provide a mixed coating composition.
• the coated substrate is prepared by contacting a substrate with the mixed coating composition.
• suitable polyisocyanate adducts are specified..hereinabove.
• the cyclodimerized polyisocyanates contain uretdione moieties and are commonly referred to as "dimers", whereas the cyclotrimerized polyisocyanates contain isocyanurate moieties and are commonly referred to as "trimers”.
• the allophanates useful in this invention are suitably made by reacting an alcohol with the designated polyisocyanate to form a carbamate intermediate, which then further reacts with additional polyisocyanate to form the desired allophanate. Methodology for forming allophanates is disclosed, for example, in U.S. Patent Nos. 5,461,135 and 5,124,427.
• polyisocyanate adducts are suitably additionally employed in the coating compositions of the present invention.
• Suitable additional polyisocyanate adducts include isocyanurates, allophanate, uretidione or biurets prepared from organic diisocyanates represented by the formula: R(NCO) 2 wherein the R represents an organic group having a molecular weight of 24 to 2100, preferably 56 to 1000.
• Preferred diisocyanates according to this invention are those represented by the above formula wherein R represents a divalent aliphatic hydrocarbon group having from 4 to 25 carbons, a divalent cycloaliphatic hydrocarbon group having from 4 to 20 carbons, or a divalent araliphatic hydrocarbon group having from 6 to 20 carbons.
• organic diisocyanates which are particularly suitable for the process include 1,4- tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4-trimethyl-1,6-hexamethylene diisocyanate, 1,10-decanemethylene diisocyanate, 1,12-dodecanemethylene diisocyanate, cyclohexane- 1,3-diisocyanate, cyclohexane-1,4-diisocyanate, 1, isocyanato-2-isocyanatomethyl cyclopentane, isophorone diisocyanate, Jbis-(4- isocyanatocyclohexyl) -methane, 1,3- and/or 1,4 -bis- (isocyanatomethyl)-cyclohexane, Jbis- (4-isocyanato-3- methyl-cyclohexyl) -methane, ⁇ , ⁇ , ⁇ ' , a' -t
• polyisocyanates can also be used and also polyisocyanates which have been modified by the introduction of urethane, allophanate, urea, biuret, carbodiimide, uretonimine or isocyanurate residues.
• the organic solvent optionally employed in the coating compositions of the present invention are is suitably a solvent that does not contain isocyanate reactive groups.
• suitable solvents are acetone, methylamyl ketone, methylethyl ketone, methyisobutyl ketone, n-methylpyrrolidone, dimethylformamide, dimethylacetamide, n- butylacetate, dipropylene glycol dimethyl ether, propylene glycol methylethylacetate, propylene glycol methylether, and other such water-compatible solvents. Mixtures of the solvents may also be used.
• the isocyanate reactive hydroxyl terminated aqueous dispersable resin polymer employed in the coating composition of the present invention suitably has a hydroxyl number of between 10 to 450. Preferably, the hydroxyl number is between 28 to
• hydroxyl-terminated polymers are represented by the formula: R ⁇ (OH) n
• R x represents (a) a polyester, or (b) a polyether, or (c) a polyurethane, or (d) a polyacrylate, or (e) a copoly(urethane-acrylate) , or a combination thereof, having a molecular weight between 200 to 8,000, preferably between 230 to 6,000.
• the functionality of the hydroxyl terminated polymer represented in the formula by n can be between 1.8 and 8, preferably between 2 and 6.
• the hydroxyl-terminated, water dispersible polymer resin according to this invention also has 1% to 20% by weight of non-ionic and/or ionic hydrophilic groups, preferably between 2 to 10%.
• the suitable non-ionic groups are polymeric ethylene oxides with 3 to 30 repeating ethylene oxide units.
• the suitable ionic groups are carboxylic, sulfonic, sulfate and quaternary ammonium groups.
• polyesters are the reaction products of one or more kinds of polycarboxylic acids such as saturated aliphatic carboxylic acids, and/or aromatic carboxylic acid and one or more kinds of polyhydric alcohols.
• polycarboxylic acids such as saturated aliphatic carboxylic acids, and/or aromatic carboxylic acid and one or more kinds of polyhydric alcohols.
• aliphatic.acids are oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, isosebacic acid, and azelaic acid.
• aromatic acids are phthalic acid, isophthalic acid, terephthalic acid and their anhydrides.
• polyhydric alcohols examples include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, l,3-butanediol, 1,4-butanediol, 2,3- butanediol, 1,5-pentanediol, 1,4-pentanediol, 1,6-
• polyethers are the polymers obtained by the reaction of starting compounds which contain reactive hydrogen atoms with alkylene oxides such as propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran, epichlorohydrin or mixtures of these alkylene oxides. Certain proportions of ethylene oxide may also be included.
• Suitable starting compounds containing at least one reactive hydrogen atom include the polyols set forth as suitable for preparing the polyhydroxy polyesters and, in addition, water, methanol, ethanol, 1,2,6- hexanetriol, 1,2,4-butanetriol, trimethylol ethane, pentaerythritol, mannitol, sorbitol, methyl glycoside, sucrose, phenol, isononyl phenol, resorcinol, hydroquinone and 1,1,1- or 1,1,2- tris(hydroxylphenyl)ethane.
• the polyethers in according to this invention have molecular weight between 150 to 8,000, preferably between 200 to 6,000. They have functionality between 1.5 to 8.
• polyurethanes are the reaction products of a diisocyanate and a polyol.
• diisocyanates suitable for this invention are organic diisocyanates represented by the formula:
• R(NCO) 2 wherein the R represents an organic group having a molecular weight of 24 to 2100, preferably 56 to 1000.
• Preferred diisocyanates according to this invention are those represented by the above formula wherein R represents a divalent aliphatic hydrocarbon group having from 4 to 25 carbons, a divalent cycloaliphatic hydrocarbon group having from 4 to 20 carbons, or a divalent araliphatic hydrocarbon group having from 6 to 20 carbons.
• organic diisocyanates which are particularly suitable for the process include ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4- trimethyl-1,6-hexamethylene diisocyanate, 1,10- decanemethylene diisocyanate, 1,12-dodecanemethylene diisocyanate, cyclohexane-1,3-diisocyanate, cyclohexane-1,4-diisocyanate, 1, isocyanato-2- isocyanatomethyl cyclppentane, isophorone diisocyanate, bis- (4-isocyanatocyclohexyl)-methane, 1,3- and/or 1,4-bis-(isocyanatomethyl) -cyclohexane, bi ⁇ - (4-isocyanato-3-methyl-cyclohexyl) -methane, ⁇ , ⁇ , ⁇ ' , ⁇ '-
• Suitable polyols include those described above as polyesters and polyethers, as well as hydroxyl terminated polylactones, and hydroxyl terminated polycarbonates. Suitable hydroxyl terminated polylactones are polymeric products of valeratelactone, or e- caprolactone having molecular weight between 400 and 6000, preferably between 650 and 3,000.
• Suitable hydroxyl terminated polycarbonates are reaction products obtained from reaction of the polydydric alcohols previously set forth for preparing the polyhydroxyl polyesters with phosgene, diaryl carbonates such diphenyl carbonate or cyclic carbonates such as ethylene or propylene carbonate. Also suitable are polyester carbonates or polyether carbonates obtained by the reaction of lower molecular weight oligomer of the above-mentioned polyesters, polylactones, or polyethers with phosgene, diaryl carbonates or cyclic carbonates.
• the hydroxyl terminated polycarbonates suitable for this invention have molecular weight between 250 to 8,000, preferably between 650 and 3,000.
• hydroxyl group-containing polyacrylates are the polymers obtained by polymerization of one or more kinds of unsaturated hydroxylacrylic monomers (e.g. 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2- hydroxyacrylate) , unsaturated acrylic acid amide
• monomers e.g. acrylamide, N-methylolacrylamide, methacrylamide
• unsaturated carboxylic acid monomers e.g. acrylic acid, methacrylic acid, itaconic acid, crotonic acid
• unsaturated acid anhydride monomers e.g. itaconic anhydride, maleic anhydride
• unsaturated glycidyl monomers e.g. glycidyl acrylate, glycidyl methacrylate
• acrylic ester monomers e.g. ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate
• methacrylic ester monomers e.g.
• maleic ester monomers e.g. dibutyl maleate, diethyl maleate
• fumaric ester monomers e.g. dibutyl fumarate, diethyl fumarate
• styrene and its derivatives e.g. Qf-methylsty
• copoly(urethane-acrylate) are copolymers prepared as described for component (c) , except between 2 to 50 percent by weight of component (d) was used as the polyol.
• the two component coating compositions according to this invention are prepared by mixing of the polyisocyanate, component (I) , into the isocyanate reactive aqueous solution and/or dispersion of hydroxyl terminated polymer, component (II) . Mixing of the two components is suitably carried out by simple stirring or shaking at room temperature without high energy.
• the quantity of the polyisocyanate component is selected to provide an NCO/OH equivalent ratio, based on the isocyanate groups of component (I) , and the hydroxyl groups of
• /% component (II) of about 1 to 5, preferably about 1.2 to 2.0.
• the mixtures prepared according to this invention have good pot-life and spray viscosity of more than two hours.
• the auxiliaries and additives typically used in coating technology may be incorporated into the isocyanate reactive component (II) .
• the auxiliaries and additives include foam inhibitors, leveling aids, pigments, dispersion aids for solid pigments, surface active agents, etc.
• the two-component coating compositions according to this invention are suitable for virtually any applications solvent- containing, solventless, or other aqueous paint and coating systems on substrates are currently used.
• the applications include the painting and coating of metal surfaces, the painting and coating of plastic surfaces, the painting, coating, or sealing of wood and wood based materials such as particle board, fiber board and paper, the painting, coating, or sealing of mineral material surfaces such as lime- and/or cement-bound building material and concrete, and the painting and coating of bitumen-containing pavements. They are also suitable for the bonding of various materials wherein the materials of two surfaces may be the same of different.
• the aqueous coating compositions according to the present invention may be applied to substrates using any of the various techniques known in the art, such as spraying, roll-on, brush-on and so on.
• J3 They can also contain pigments, levelling agents, catalysts, and other auxiliaries known in the art.
• the HDI dimer/HDI trimer isocyanate crosslinker was prepared by blending: (a) 100 parts of low viscosity hexamethylene diisocyanate (HDI) dimer; (b) 100 parts of HDI trimer; and (c) 35.29 parts of dipropylene glycol dimethyl ether (commercially available as PROGLYDE DMM, a product of Dow Chemical Company) . These materials were stirred for 30 minutes at room temperature.
• HDI dimer/HDI trimer isocyanate crosslinker was prepared by blending: (a) 100 parts of low viscosity hexamethylene diisocyanate (HDI) dimer; (b) 100 parts of HDI trimer; and (c) 35.29 parts of dipropylene glycol dimethyl ether (commercially available as PROGLYDE DMM, a product of Dow Chemical Company) . These materials were stirred for 30 minutes at room temperature.
• isophorone isophorone
• IPDI diisocyanate
• DMPA dimethylol propionic acid
• NMP N-methyl pyrrolidinone
• T-12 dibutlytin dilaurate
• DMEA dimethylethanolamine
• Crosslinking of the two-component composition was effected by first adding to an eight ounce glass bottle the following ingredients: isocyanate crosslinker (from Step l of the present Example) in an amount of 18.17 parts; dispersion of ionomer
• the coated test panels were allowed to cure at ambient temperature and humidity conditions for two weeks before testing for appearance, mechanical properties, and chemical resistance.
• Pencil hardness was determined according to ASTM D3363-92a.
• the conical mandrel bend tests were performed using a one-eight inch tester from BYK-Gardner, Inc. according to ASTM D522-92.
• Direct and reverse impact values were determined according to ASTM D2794-92 using a variable height impact tester from BYK-Gardner, Inc.
• Gloss was determined using a micro-TRZ-gloss, multi-angle glossmeter from BYK- Gardner.
• Cross-hatch adhesion was determined using a cross-hatch cutter from BYK-Gardner according to ASTM D3359-92a. Chemical Resistance was determined according to ASTM D1308-87.
• trimer/allophanate variation was prepared using the procedure of Example 1, step 1, but without solvent: HDI Trimer 35.00 parts ALLOPHANATE 35.00 parts
• trimer/allophanate variation was prepared using the procedure of Example 1, Step l: IPDI Trimer 35.00 parts ALLOPHANATE 35.00 parts DMM 17.50 parts

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• Organic Chemistry (AREA)
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• Life Sciences & Earth Sciences (AREA)
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• Wood Science & Technology (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Manufacturing & Machinery (AREA)
• Polyurethanes Or Polyureas (AREA)
• Paints Or Removers (AREA)

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• 1997
  • 1997-04-07 JP JP09542359A patent/JP2000514469A/ja not_active Ceased
  • 1997-04-07 AU AU26699/97A patent/AU2669997A/en not_active Abandoned
  • 1997-04-07 CN CN97196951A patent/CN1230971A/zh active Pending
  • 1997-04-07 WO PCT/US1997/006251 patent/WO1997045475A1/en not_active Application Discontinuation
  • 1997-04-07 BR BR9709486A patent/BR9709486A/pt not_active Application Discontinuation
  • 1997-04-07 KR KR10-1998-0711018A patent/KR100509342B1/ko not_active IP Right Cessation
  • 1997-04-07 CA CA002257283A patent/CA2257283A1/en not_active Abandoned
  • 1997-04-07 EP EP97918640A patent/EP0907673A4/de not_active Withdrawn

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