Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
  • C09J175/04—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
  • C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• • 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
  • C08G18/1825—Catalysts containing secondary or tertiary amines or salts thereof having hydroxy or primary amino groups

Definitions

• the invention relates to a one-component polyurethane reaction adhesive with end-to-end NCO groups (1-component PüR reaction adhesive) based on at least one polyisocyanate, at least one NCO-reactive oligomer and at least one catalyst, and its preparation and use.
• 1-component PU reaction adhesives are known (see, for example, habenicht, gerd "adhesive bonding: basics, technology, applications” 2nd edition, 1990, pages 65 and 66). They usually contain aromatic polyisocyanates and polyols or prepolymers made therefrom with NCO groups and catalysts and other additives. In the presence of humidity, they set within 10 to 60 minutes.
• the catalysts are usually tin compounds and / or tertiary amines in concentrations of up to 1% by weight. Higher catalyst concentrations generally lead to adhesives that are not stable in storage because side reactions are also accelerated, which cause the viscosity to rise to an unacceptably high level within a few months.
• the aromatic 1-component PUR reaction adhesives are brownish or turn brown over time if they are based on aromatic isocyanates. In addition, they have to be labeled because of the aromatic polyisocyanates and their vapor pressure and their toxicology.
• 1-component PU reaction adhesives made from aliphatic diisocyanates are also mentioned. Trimerization products of aliphatic diisocyanates would be particularly advantageous since they contain only small amounts of volatile isocyanates and are therefore less toxicologically unsafe and do not have to be labeled. However, the aliphatic isocyanates have the disadvantage of reacting much more slowly than aromatic ones. For this reason, they cannot be used in practice for many applications.
• the object of the invention is to find a 1-component reaction adhesive which reacts faster than the known systems, but is nevertheless stable in storage and practically does not deteriorate with respect to the other properties, but rather improves if possible, eg regarding toxicology.
• the 1-component PU reaction adhesive according to the invention is therefore characterized in that it contains at least one tertiary amine with at least one functional group for incorporation into the polymer chain as a catalyst.
• the number of functional groups of the tertiary amine is preferably 2. However, 3 or 1 functional groups per tertiary amine are also possible.
• the number of these reactive tertiary amines is at least and preferably 1. However, it is also expedient to use 2 different tertiary amines, which are, for. B. differ in their functionality. The number of reactive tertiary amines is theoretically unlimited, but in practice it should not be greater than 5. All or part of the tertiary amine can be replaced by a quaternary ammonium compound.
• the reactive tertiary amines expediently contain the following functional groups: -OH, -SH, -COOH, -NCO, -NH2 and -NHR, where R is an alkyl group with 1 to 25 C atoms. Hydroxyl-containing amines are preferably used.
• N N-dimethylethanolamine
• N N-dimethyldiaminoethane
• N-methyldiethanolamine N, N-dimethyl-2- (2-dimethylaminoethoxy) ethanol
• NNN-trimethyl-N-hydroxethyl-diaminoethane-bisaminoethyl ether N, N-bis (3-dimethylaminopropyl) N-isopropanolamine
• Tetramethyliminobispropylamine and N- (3-dimethylaminopropyl-) N, N-diisopropanolamine should advantageously be used in an amount of 1 to 30, preferably 2 to 10 g per 100 g of prepolymer. Outside of this range, there are disadvantages, be it that the reactivity decreases significantly or that the adhesive becomes brittle.
• aliphatic isocyanate groups Due to the high concentration of catalyst, aliphatic isocyanate groups also react sufficiently quickly at room temperature and surprisingly are nevertheless stable in storage.
• polyfunctional aromatic and aliphatic isocyanates and / or oligomerized products with NCO groups produced therefrom can be used to produce the one-component PIIR reaction adhesives according to the invention.
• multi-functional is meant a functionality of the isocyanate component of greater than 1.0.
• the isocyanate component can also be a mixture of isocyanates.
• the suitable polyfunctional isocyanates preferably contain on average 2 to at most 5, preferably up to 4, NCO groups.
• suitable isocyanates are phenyl isocyanate, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), hydrogenated MDI (H12MDI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), 4,4'-diphenyldimethylmethane diisocyanate - And tetraalkyldiphenylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, the isomers of tolylene diisocyanate (TDI), optionally in a mixture, l-methyl-2,4-diisocyanato -cyclohexane, 1,
• Sulfur-containing polyisocyanates are obtained, for example, by reaction of 2 mol of hexamethylene diisocyanate with 1 mol of thiodiglycol or dihydroxy-dihexyl sulfide.
• Other important diisocyanates are trimethylhexamethylene diisocyanate, 1,4-diisocyanatobutane, 1,12-diisocyanatododecane and dimer fatty acid diisocyanate.
• polystyrene foams which enable the formation of self-crosslinking polyurethanes, for example dimeric tolylene diisocyanate, or partially or completely reacted polyisocyanates with, for example, phenols, tertiary butanol, phthalimide, caprolactam.
• the isocyanate component partially contains dimer fatty acid isocyanate.
• Dimer fatty acid is a mixture of predominantly C35 dicarboxylic acids which is prepared by thermal or catalytic dimerization of unsaturated Ciss-monocarboxylic acids, such as oleic acid, tall oil fatty acid or linoleic acid. Such dimer fatty acids have long been known to the person skilled in the art and are commercially available.
• the dimer fatty acid can be converted into dimer fatty acid isocyanates.
• Technical dimer fatty acid diisocyanate has on average at least two and less than three isocyanate groups per molecule of dimer fatty acid.
• Diisocyanates trimerized to isocyanurates are particularly suitable for the preparation of low-diisocyanate 1-component PU reaction adhesives, e.g. the isocyanurate from HDI and IPDI.
• the trimerization reaction takes place in the presence of suitable trimerization catalysts (see, for example, Kunststoff-Handbuch, Vol. 7, Polyurethane, page 108).
• trimerization catalysts see, for example, Kunststoff-Handbuch, Vol. 7, Polyurethane, page 108.
• Mixtures of cyclotrimerizates of aliphatic and cycloaliphatic diisocyanates, in particular mixed trimerizates thereof, are particularly advantageous.
• polymer MDI polymer MDI
• Tri-MDI 3-functional homologue of the MDI.
• the main main components of the polyisocyanates are higher homologs of MDI (polymer MDI) or aliphatic polyisocyanates, in particular trimerized diisocyanates and especially trimerized HDI are used.
• oligomerized NCO-terminal adducts from the above-mentioned isocyanates and polyols, polyamines or amino alcohols, in particular adducts of aliphatic isocyanates.
• Suitable polyols are preferably 1 to 5, in particular 1 to 3, of the organic polyhydroxyl compounds known per se for the production of high molecular weight compounds in the PUR chip.
• the known polyhydroxy polyethers of the molecular weight range from 60 to 10,000, preferably 70 to 6,000 with 2 to 10 hydroxyl groups per molecule are suitable.
• Such polyhydroxy polyethers are obtained in a manner known per se by alkoxylation of suitable starter molecules, e.g.
• Suitable alkoxylating agents are especially propylene oxide and optionally ethylene oxide.
• polyester polyols in the molecular weight range from 400 to 10,000 are also suitable for foam production if they contain 2 to 6 hydroxyl groups.
• Suitable polyester polyols are the reaction products, known per se, of excess amounts of polyhydric alcohols of the type already mentioned as starter molecules with polybasic acids such as, for example, succinic acid, adipic acid, phthalic acid, tetrahydrophthalic acid or any mixtures of such acids.
• Polycarbonate polyols are also suitable.
• polyvalent primary or secondary amines can also be used as chain building blocks, as can aminocarboxylic acids and low molecular weight protein compounds.
• the proportion of these substances should be less than 20, preferably 10 mol%, based on the polyols.
• Polyether and / or polyester polyols are preferably used as polyols.
• NCO groups can react with monofunctional substances, in particular with monoalcohols, amines and carboxylic acids.
• the equivalent ratio of isocyanate groups (NCO) to groups with active hydrogen (AKH) should be 2: 1 to 0.5: 1, preferably 1.5: 1 to 0.6: 1. If, in addition to the described reactions with compounds with active hydrogen, a trimerization of excess isocyanate groups is desired, the ratio of NCO: active hydrogen can also be up to 5: 1.
• the isocyanate content of the adhesive according to the invention is in the range from 0.5 to 20 g NC0 / 100 g adhesive, in particular from 1 to 15 g NC0 / 100 g.
• the customary catalysts can also be used, in particular the following tertiary amines: diazabicyclo-octane (Dabco), triethylamine, dimethylbenzylamine (Desmorapid DB, BAYER), bis-dimethylaminoethyl ether (Calalyst Al, UCC), tetramethyl guanidine, bis-dimethylaminomethyl-phenol, 2,2'-dimorpholinodiethyl ether, 2- (2-dimethylaminoethoxy) ethanol, 2-dimethylaminoethyl-3- dimethylaminopropyl ether, bis (2-dimethylaminoethyl) ether, N, N-dimethylpiperazine, N- (2-hydroxyethoxyethyl) -2-azanorborane, Tacat DP-914 (Texaco Chemical), Jeffcat TM, N, N, N, N, N, N, N, N, N
• the catalysts can also be in oligomerized or polymerized form, e.g. as N-methylated polyethyleneimine.
• 1-methylimidazole 2-methyl-1-vinylimidazole, 1-allylimidazole, 1-phenylimidazole, 1, 2,4,5-tetramethylimidazole, 1 (3-aminopropyl) imidazole, pyrimidazole, 4- Dimethylamino-pyridine, 4-pyrrolidinopyridine, 4-morpholino-pyridine, 4-methylpyridine and N-dodecyl-2-methylimidazole.
• organometallic compounds such as tin (II) salts of carboxylic acids, strong bases such as alkali hydroxides, alcoholates and phenolates, e.g. Di-n-octyl-tin mercaptide, dibutyl tin maleate, diacetate, dilaurate, dichloride, bisdodecyl mercaptide, tin II acetate, ethyl hexoate and diethyl hexoate or lead phenyl ethyl dithiocarbaminate.
• DABCO, TMR-2 etc. from Air Products may be mentioned as the trimerization catalyst, which are quaternary ammonium salts dissolved in ethyl glycol.
• reaction adhesive according to the invention can also contain conventional additives, such as. B. filler fibers, pigments, defoamers, adhesion promoters, plasticizers, anti-aging agents and CO 2 -absorbing or adsorbing additives, eg. B. molecular sieves and silica gel.
• additives such as. B. filler fibers, pigments, defoamers, adhesion promoters, plasticizers, anti-aging agents and CO 2 -absorbing or adsorbing additives, eg. B. molecular sieves and silica gel.
• substances can also be added that react chemically with the CO2, e.g. B. CaO.
• the reaction adhesive according to the invention has a medium-viscosity to pasty viscosity (approx. 200 to 100,000 mPas) at processing temperature, in particular a medium-viscosity to viscous viscosity (approx. 200 to 20,000 mPas).
• the viscosity changes only slightly during storage, ie the adhesive is still usable. Specifically, the viscosity changes within 4 months at 40 ° C. with exclusion of moisture at most in the range from -50 to +100%, in particular from -30 to +50%, based on the initial viscosity.
• the viscosity is determined using a Brookfield viscometer.
• the reaction adhesive according to the invention has NCO groups in such amounts that there is a noticeable solidification subsequently.
• the NCO content should expediently be in a range from 0.5 to 20 g of NCO per 100 g of adhesive.
• the NCO content is determined according to DIN 53185 and DIN 16945 or ASTM-D 1638.
• the reaction adhesive according to the invention can be produced as usual.
• the preparation is preferably carried out in such a way that low-monomer end products are obtained.
• reaction adhesive is sufficiently stable in storage, i. H. it does not change its viscosity within -50 to +100%, preferably -30 to +50, if it is stored for 4 months at 40 ° C in the absence of moisture.
• reaction adhesive are practically not negatively changed by the addition of the reactive catalyst. This applies in particular to rheology.
• the adhesive can be used universally because it adheres to many substrates.
• the 1-component PU reactive adhesive according to the invention can be used as an adhesive, coating material or sealant, in particular as a multi-purpose adhesive (household adhesive), assembly adhesive, construction adhesive, paper and packaging adhesive, Foil laminating adhesive or hot melt adhesive.
• a multi-purpose adhesive household adhesive
• assembly adhesive construction adhesive
• paper and packaging adhesive Foil laminating adhesive or hot melt adhesive.
• Adhesive is produced from the above-mentioned starting materials in the amounts given in the table (in g / 100 g prepolymer) in the following way: All components are stirred at 70 to 90 ° C. for 2 to 3 hours with the exclusion of moisture until the NCO - Does not change anymore.
• the NCO content was determined according to DIN 53185 and 16945 or ASTM-D 1638.
• the tensile strength (ZSF) was determined by producing overlapping bonds of beech plywood test specimens stored at 23 ° C./50% relative humidity, of which the tensile strengths were measured after 3 days using a tensile tester at 50 mm / min.
• the setting time was determined by producing test specimens as described for the tensile shear strength and determining the ZSF after different times. If the ZSF is approx. 1 MPa, the elapsed time corresponds to the setting time.
• the storage stability was determined by storing samples of the adhesives at 40 ° C. in closed vessels and, after certain periods of time, measuring the viscosity at 23 ° C. using a Brookfield viscometer.
• Aerosil 200 8.0 - _ - - - - 5.0 - b) carbon black - - - - - - - - - ro

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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)
• Adhesives Or Adhesive Processes (AREA)
• Polyurethanes Or Polyureas (AREA)

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• 1996
  • 1996-11-13 DE DE19646879A patent/DE19646879A1/de not_active Withdrawn
  • 1996-11-14 JP JP9519357A patent/JP2000501128A/ja active Pending
  • 1996-11-14 CA CA 2238412 patent/CA2238412A1/en not_active Abandoned
  • 1996-11-14 EP EP96939033A patent/EP0862592A1/de not_active Withdrawn
  • 1996-11-14 WO PCT/EP1996/004982 patent/WO1997019122A1/de not_active Application Discontinuation

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