Classifications

• • 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
  • C09D175/06—Polyurethanes from polyesters
• • 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
  • C08G18/16—Catalysts
  • C08G18/18—Catalysts containing secondary or tertiary amines or salts thereof
  • C08G18/1875—Catalysts containing secondary or tertiary amines or salts thereof containing ammonium salts or mixtures of secondary of tertiary amines and acids
• • 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
  • C08G18/798—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing urethdione groups

Definitions

• the invention relates to uretdione-group-containing polyurethane compositions which cure at low stoving temperatures, processes for the preparation of such compositions and their use for the production of plastics, in particular lacquer coatings and adhesives.
• DE-OS 27 35 497 PUR coatings with excellent weathering and heat stability The crosslinkers, the preparation of which is described in DE-OS 27 12 931, consist of ⁇ -caprolactam blocked isocyanurate-containing isophorone diisocyanate. There are also known urethane, biuret or urea group-containing polyisocyanates whose isocyanate groups are also blocked.
• DE-OS 30 30 539 and DE-OS 30 30 572 describe processes for the preparation of uretdione polyaddition compounds whose terminal isocyanate groups are blocked irreversibly with monoalcohols or monoamines.
• Hydroxyl-terminated, polyaddition compounds containing uretdione groups are the subject of EP 669 353. Due to their functionality of two, they have improved resistance to solvents. The compositions based on these uretdione group-containing polyisocyanates have in common that they do not emit volatile compounds in the curing reaction. However, the baking temperatures are at least 180 0 C at a high level.
• amidines as catalysts in PU coating composition is described in EP 803 524. Although these catalysts lead to a lowering of the curing temperature, but show a considerable yellowing, which is generally undesirable in the coating area. The reason for this yellowing is probably the reactive nitrogen atoms in the amidines. These can react with atmospheric oxygen to N-oxides, which are responsible for the discoloration.
• EP 803 524 also mentions other catalysts which have hitherto been used for this purpose, but without showing any particular effect on the curing temperature. These include known from polyurethane chemistry organometallic catalysts such. As dibutyltin dilaurate (DBTL), or tertiary amines, such as. B. 1, 4-diazabicyclo [2.2.2] octane (DABCO).
• DBTL dibutyltin dilaurate
• DABCO 4-diazabicyclo [2.2.2] octane
• Allophanates are the reaction products one mole of alcohol and two moles of isocyanate, while in conventional urethane chemistry, one mole of alcohol reacts with one mole of isocyanate. Due to the unwanted allophanate formation so technically and economically valuable isocyanate groups are destroyed.
• the object of the present invention was therefore to find highly reactive uretdione-containing polyurethane compositions which can be cured even at very low temperatures and are particularly suitable for the production of plastics and high-gloss or matt, light and weather-stable highly reactive coating and adhesive compositions.
• Conventional uretdione-containing polyurethane compositions can be cured under normal conditions (DBTL catalysis) only from 180 0 C.
• DBTL catalysis normal conditions
• the low-temperature curing polyurethane compositions according to the invention not only energy and (curing) time can be saved at from 100 to 160 0 C curing, but it can also be coated or bonded many temperature-sensitive substrates that at 180 0 C undesirable yellowing , Decomposition and / or embrittlement phenomena.
• certain aluminum substrates are also suitable. In the latter case, an excessively high temperature load sometimes leads to an undesired change in the crystal structure.
• the present invention relates to highly reactive uretdione-containing polyurethane compositions containing essentially A) at least one uretdione-containing hardener based on aromatic, aliphatic, (cyclo) aliphatic or cycloaliphatic polyisocyanates and hydroxyl-containing compounds having a free NCO content of less than 5% by weight and a uretdione content of from 1 to 35% by weight, B) optionally a hydroxyl-containing polymer having an OH number between 20 and 500 mg KOH / gram C) at least one catalyst of the formula [NR 1 R 2 R 3 R 4 ] + [R 5 ] " , wherein R 1 - R 4 are simultaneously or independently alkyl, aryl, aralkyl, heteroaryl, alkoxyalkyl, each linear or branched , unbridged or bridged with other radicals R 1 - R 4 , with the formation of cycles, bicyclic or tricyclic and the bridging atoms
• G optionally auxiliaries and additives.
• Another object of the invention is also a process for the preparation of the polyurethane compositions.
• the invention also provides the use of the polyurethane compositions according to the invention for the production of liquid and powdery
• Lacquer coatings on metal, plastic, glass, wood or leather substrates or other heat-resistant substrates are Lacquer coatings on metal, plastic, glass, wood or leather substrates or other heat-resistant substrates.
• the invention also provides the use of the polyurethane compositions according to the invention as adhesive compositions for bonding metal, plastic, glass, wood or leather substrates or other heat-resistant substrates.
• the invention likewise relates to metal coating compositions, in particular for automobile bodies, motorcycles and bicycles, building parts and household appliances, wood coating compositions, glass coating compositions, leather coating compositions and plastic coating compositions.
• Uretdione group-containing polyisocyanates are well known and are described, for example, in US 4,476,054, US 4,912,210, US 4,929,724 and EP 417,603.
• a comprehensive review of industrially relevant processes for the dimerization of isocyanates to uretdiones is provided by J. Prakt. Chem. 336 (1994) 185-200.
• the reaction of isocyanates to uretdiones in the presence of soluble dimerization catalysts such.
• dialkylaminopyridines, trialkylphosphines, phosphorous acid triamides or imidazoles are examples of soluble dimerization catalysts.
• the reaction - optionally carried out in solvents, but preferably in the absence of solvents - is stopped when a desired conversion is achieved by addition of catalyst poisons. Excess monomeric isocyanate is subsequently separated by short path evaporation. If the catalyst is volatile enough, the reaction mixture can be freed from the catalyst in the course of the monomer separation. The addition of catalyst poisons can be dispensed with in this case.
• a wide range of isocyanates is suitable for the preparation of polyisocyanates containing uretdione groups.
• IPDI isophorone diisocyanate
• HDI hexamethylene diisocyanate
• HDI 4,4'-dicyclohexylmethylene diisocyanate
• hydrogenated MDI hydrogenated MDI
• MDI 2-methylpentane diisocyanate
• MPDI 2-methylpentane diisocyanate
• TMDI 2,2,4-trimethyl-hexamethylene diisocyanate / 2,4,4 - Trimethyl hexamethylene diisocyanate
• NBDI norbornane diisocyanate
• MDI methylene diphenyl diisocyanate
• MDI toluidine diisocyanate
• TMXDI tetramethylxylylene diisocyanate
• VXDI tetramethylxylylene diisocyanate
• uretdione group-bearing polyisocyanates to uretdione groups having curing agents A) includes the reaction of the free NCO groups with hydroxyl-containing monomers or polymers, such as.
• polyesters polythioethers, polyethers, polycaprolactams, polyepoxides, polyester amides, polyurethanes or low molecular weight di-, tri- and / or tetra alcohols as chain extenders and optionally monoamines and / or monoalcohols as chain terminators and has been described frequently (EP 669 353, EP 669 354, DE 30 30 572, EP 639 598 or EP 803 524).
• Preferred uretdione curing agents A) have a free NCO content of less than 5% by weight and a uretdione group content of 1 to 35% by weight (calculated as C 2 N 2 O 2 , molecular weight 84). Preference is given to polyesters having an OH number of 30 to 150 mg KOH / g and an average molecular weight of 500 to 6000 g / mol and monomeric dialcohols, such as.
• ethylene glycol propanediol (1, 2) and - (1, 3), 2,2-dimethylpropane (1, 3), butanediol (1, 4), hexanediol (1, 6), 2-methylpentanediol -1, 5, 2,2,4-thmethylhexanediol (1,6), 2,4,4-thymethylhexanediol (1,6), heptanediol (1,7), dodecanediol (1,12), octa -decene-9,10-diol- (1,12), thiodiglycol, octadecanediol (1,18), 2,4-dimethyl-2-propylheptanediol (1,3), diethylene glycol, triethylene glycol, tetraethylene glycol , trans and cis-1,4-cyclohexanedimethanol used.
• the hardeners may also have isocyanurate, biuret, allophanate, urethane and / or urea structures.
• polyesters As hydroxyl-containing polymers B) it is preferred to use polyesters, polyethers, polyacrylates, polyurethanes, polyethers and / or polycarbonates having an OH number of 20-500 (in mg KOH / gram). Particularly preferred Polyester with an OH number of 30 - 150, an average molecular weight of 500
• the invention also provides the use of at least one catalyst C) of the formula [NR 1 R 2 R 3 R 4 ] + [R 5 ] " , where R 1 -R 4 are simultaneously or independently alkyl, aryl, aralkyl, Heteroaryl, alkoxyalkyl, each linear or branched, unbridged or bridged with other radicals R 1 - R 4 , to form cyclen, bicyclic or tricyclic and the bridging atoms in addition to carbon may also be heteroatoms, having 1-18 carbon atoms and each radical R 1 - R 4 may additionally have one or more alcohol, amino, ester, keto, thio, urethane, urea, allophanate, double bonds, triple bonds or halogen atoms, and R 5 is either Cl, Br, or I. means, wherein these catalysts can be surrounded with an inert shell and thus encapsulated, in polyurethane compositions and the catalysts themselves.
• the catalysts C) essential to the invention satisfy the formula [NR 1 R 2 R 3 R 4 J + [R 5 ] " , where R 1 -R 4 simultaneously or independently of one another are alkyl, aryl, aralkyl, heteroaryl, alkoxyalkyl radicals, in each case linear or branched, unbridged or bridged with other radicals R 1 -R 4 , with the formation of cycles, bicyclic or tricyclic radicals and the bridging atoms in addition to carbon may also be heteroatoms having 1-18 carbon atoms and each radical R 1
• R 4 additionally one or more alcohol, amino, ester, keto, thio, urethane, urea, allophanate, double bonds, triple bonds or
• Halogen atoms may have, and R 5 is either Cl, Br, or I, said catalysts may be surrounded with an inert shell and encapsulated therewith.
• Examples of such catalysts under C) are tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide, tetraethylammonium chloride,
• tetrabutylammonium chloride are in an amount of 0.001 to 5 wt .-%, preferably 0.01 to 3 wt .-%, particularly preferably from 0.5 to 1, 5 wt .-%, based on the components A) and B) in of the
• the catalysts can be any organic solvent used to produce Paint or adhesive composition included.
• the catalysts can be any organic solvent used to produce Paint or adhesive composition included.
• the catalysts can be any organic solvent used to produce Paint or adhesive composition included.
• a variant of the invention includes the polymeric attachment of such catalysts C) to the curing agent A) or to the hydroxyl-containing
• Ammonium salts with acid, isocyanate, or glycidyl groups of the hardener A) or hydroxyl-containing polymers B) are reacted to integrate the catalysts C) in the polymeric composite.
• the conventional reactants of the uretdione-containing hardener include hydroxyl-containing
• Polyester Due to the method of preparation of polyesters, these sometimes wear in small extent nor acid groups. In the presence of such acid-group-bearing polyesters, it makes sense to use the catalysts mentioned either in excess relative to the acid groups, or to add reactive compounds which are capable of intercepting acid groups. Both monofunctional and polyfunctional compounds can be used for this purpose.
• Reactive acid-scavenging compounds D are well known in paint chemistry.
• inorganic salts such as hydroxides, bicarbonates or carbonates with acid groups at elevated temperatures.
• Triglycidyl ether isocyanurate (TGIC), Araldit PT 910, Araldit PT912 (mixtures of di- and triglycidyl esters, Hunstman), EPIKOTE 828 (diglycidyl ether based on bisphenol A, Schell), Versaticklareglycidylester, Ethylhexylglycidylether, Butylglycidylether, POLYPOX R 16 (pentaerythritol tetra- glycidyl ether, UPPC AG) as well as other types of polypoets with free epoxy groups, VESTAGON EP HA 320, (hydroxyalkylamide, Degussa AG), but also phenylenebisoxazoline, 2-methyl-2-oxazoline, 2-hydroxyethyl-2-oxazoline, 2-hydroxypropyl-2- oxazoline, 5-hydroxypentyl-2-oxazoline, sodium
• Acids which are mentioned under E) are all substances, solid or liquid, organic or inorganic, monomeric or polymeric, which have the properties of a Bronsted or a Lewis acid. Examples include: sulfuric acid, acetic acid, benzoic acid, malonic acid, terephthalic acid, phthalic acid, succinic acid, but also copolyesters or copolyamides having an acid number of at least 20.
• Suitable solvents under F) are all liquid substances which do not react with other ingredients, eg. Acetone, ethyl acetate, butyl acetate, xylene, Solvesso 100, Solvesso 150, methoxypropyl acetate and dibasic ester.
• polyurethane compositions customary in the paint or adhesive technology additives G) as leveling agents for.
• leveling agents for.
• additional catalysts such as are already known in polyurethane chemistry may be included.
• organometallic catalysts such as. As dibutyltin dilaurate, or tertiary amines, such as. B. 1, 4-diazabicyclo [2.2.2,] octane, in amounts of 0.001 -1 wt .-%.
• the homogenization of all constituents for the preparation of the polyurethane composition according to the invention can be carried out in suitable aggregates, such. As heated stirred tanks, kneaders, or extruders, carried out, with upper temperature limits of 120 to 130 0 C should not be exceeded.
• the homogeneous mixture of all constituents depending on the starting substances or after the use of solvents, either solid or liquid.
• the well-mixed mass is applied to the substrate by suitable application (eg rolling, spraying).
• suitable application eg rolling, spraying
• the application of ready to spray powders on suitable substrates by the known methods, such. B. by electrostatic powder spraying, vortex sintering, or electrostatic vortex sintering.
• the coated workpieces are heated to a temperature of 60 to 220 0 C, preferably 6 to 30 minutes at 80 to 160 0 C for curing for 4 to 60 minutes.
• crushed feedstocks are intimately mixed in a muller and then homogenized in the extruder to a maximum of 130 0 C. After cooling, the extrudate is crushed and ground with a pin mill to a particle size ⁇ 100 microns.
• Lacquer compositions (in% by weight):
• Examples 2 and 3 each still contained 1, 6% Araldit PT 912, 0.5% benzoin, 1, 0% Resiflow PV 88 and 30.0% Kronos 2160
• Examples 1 and V1 were sprayed onto steel sheets and cured at 30 '160 0 C.
• Examples 2 and 3 were sprayed on steel sheets and cured at 15 '150 0 C.
• the MEK test (double strokes) reflects the solvent resistance (methyl ethyl ketone) of the coating, while the pendulum hardness allows a statement about the hardness of the coating. Both are dependent on networking the coating. Obviously, sufficient crosslinking has taken place in Inventive Example 1, but not in Comparative Example 1.
• Both examples 2 and 3 are fully cured and have good paint mechanics.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Polyurethanes Or Polyureas (AREA)
• Paints Or Removers (AREA)
• Adhesives Or Adhesive Processes (AREA)

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• 2006
  • 2006-09-07 DE DE200610042494 patent/DE102006042494A1/de not_active Withdrawn
  • 2006-09-14 CN CNA2006101495098A patent/CN101139461A/zh active Pending
• 2007
  • 2007-08-15 JP JP2009527091A patent/JP2010502797A/ja not_active Withdrawn
  • 2007-08-15 WO PCT/EP2007/058457 patent/WO2008028769A1/de active Application Filing

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