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
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/40—High-molecular-weight compounds
  • C08G18/48—Polyethers
  • C08G18/4825—Polyethers containing two hydroxy groups
• • 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
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/2805—Compounds having only one group containing active hydrogen
  • C08G18/2815—Monohydroxy compounds
  • C08G18/282—Alkanols, cycloalkanols or arylalkanols including terpenealcohols
• • 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
  • C08G18/71—Monoisocyanates or monoisothiocyanates
  • C08G18/718—Monoisocyanates or monoisothiocyanates containing silicon
• • 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
  • C08G2190/00—Compositions for sealing or packing joints

Definitions

• the present invention relates to polyoxysilane-modified polyurethanes and their use as binders for sealants.
• Alkoxysilane-functional polyurethanes which crosslink via a silane polycondensation have long been known. A review on this topic can be found eg in "Adhesives Age” 4/1995, page 30 ff. (Authors: Ta-Min Feng, BA Waldmann). Such alkoxysilane-terminated, moisture-curing, one-component polyurethanes are increasingly being used as soft-elastic coating, sealing and adhesive compounds in construction and in the automotive industry. Preparation processes for such alkoxysilane-functional polyurethanes are described in various publications, inter alia in US Pat. No. 3,627,722 or US Pat. No. 3,632,557.
• a disadvantage of these methods is the high resulting viscosity, which requires the use of solvents or, at low viscosity, the poor suitability for use in low-modulus sealants.
• various approaches are described, for example, in US Pat. No. 3,627,722 and EP-A 0 596 360, all of which have the disadvantage that in the preparation of the alkoxysilane-functional polyurethanes, intermediates are passed through which are very unstable and thus pose a high safety risk and severely limit the reproducibility of the reactions.
• prepolymers having the required properties can be prepared by reacting polyethers having a number-average molecular weight of> 20,000 g / mol with OH-reactive silane building blocks.
• the invention therefore relates to polyurethanes modified with alkoxysilane groups, which are obtainable by reacting the components A and B in the sense of a urethanization:
• X, Y, Z are independently linear, cyclic or branched Ci-Cg-alkyl or Ci-C 8 alkoxy, wherein at least one of Radicals is a C 1 -C 8 -alkoxy group and X, Y or Z can also be bridged independently of one another,
• R is any at least difunctional organic radical, preferably a straight-chain, branched or cyclic Alkylenradical having 1 to 8 carbon atoms.
• X, Y, and Z in formula (I) are independently methoxy or ethoxy.
• radical R a methylene or propylene radical is particularly preferred.
• component A) has a number average molecular weight of 21,000 g / mol to 25,000 g / mol.
• the invention further provides sealants based on the alkoxysilane-modified polyurethanes according to the invention which have a modulus at 100% elongation of not more than 0.4 N / mm 2 (according to ISO 11600) and a maximum of 30% by weight of plasticizer, preferably at most Contain 25 wt .-% plasticizer, more preferably at most 20 wt .-% plasticizer.
• Polyol component A) which can be used according to the invention are the polyether polyols customary in polyurethane chemistry. These are accessible in a manner known per se by alkoxylation of suitable starter molecules with base catalysis or use of double metal cyanide compounds (DMC compounds).
• suitable starter molecules for the preparation of polyether polyols are molecules having at least 2 element-hydrogen bonds which are reactive toward epoxides or any mixtures of such starter molecules.
• Suitable starter molecules for the preparation of polyether polyols are, for example, simple, low molecular weight polyols, water, ethylene glycol, propanediol 1, 2, 2,2-bis (4-hydroxyphenyl) propane, Propylene glycol-1,3- and 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 2-ethylhexanediol-1, 3, trimethylolpropane, glycerol, pentaerythritol, sorbitol, organic polyamines having at least two NH bonds such as triethanolamine, ammonia , Methylamine or ethylenediamine or any mixtures of such starter molecules.
• Alkylene oxide suitable for the alkoxylation is in particular propylene oxide.
• propylene oxide polyethers having from 1.5 to 3.5 hydroxyl groups, more preferably from 1.8 to 2.5.
• Polyethers prepared by double metal cyanide catalysis generally have a particularly low content of unsaturated end groups of less than or equal to 0.02 meq / gram of polyol (meq / g), preferably less than or equal to 0.015 meq / g, more preferably less than or equal to 0, 01 meq / g (method of determination ASTM D2849-69), contain significantly fewer monols and usually have a low polydispersity of less than 1.5.
• polyethers prepared by double metal cyanide catalysis.
• Particularly preferred are polyethers which have a polydispersity of 1.0-1.5; most preferably a polydispersity of 1.0 to 1.3.
• Such polyethers are e.g. in US Pat. No. 5,158,922 and EP-A 0 654 302.
• polyoxyalkylene polyols can be used in pure form or as a mixture of different polyethers.
• isocyanate- and alkoxysilane-containing compounds B all alkoxysilane-containing monoisocyanates are suitable in principle.
• Examples of such compounds are isocyanatomethyltrimethoxysilane, isocyanatomethyltriethoxysilane, (isocyanatomethyl) methyldimethoxysilane, (isocyanatomethyl) methyldiethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropylmethyldimethoxysilane, 3-isocyanato propyltriethoxysilane and 3-isocyanatopropylmethyldiethoxysilane.
• Preferred here is the use of 3-isocyanatopropyltrimethoxysilane.
• isocyanate-functional silanes prepared by reacting a diisocyanate with an amino or thiosilane, as described in US Pat. No. 4,146,585 or EP-A 1 136 495.
• the urethanization of components A) and B) may optionally be carried out using a catalyst.
• Suitable catalytically active compounds which are known to the person skilled in the art are known urethanization catalysts such as organotin compounds or amine catalysts.
• organotin compounds are: dibutyltin diacetate, dibutyltin dilaurate, dibutyltin bis-acetoacetonate and tin carboxylates such as, for example, tin octoate.
• the said tin catalysts may optionally be used in combination with amine catalysts such as aminosilanes or 1,4-diazabicyclo [2.2.2] octane.
• Dibutyltin dilaurate is particularly preferably used as the urethanization catalyst.
• the course of the urethanization reaction can be monitored by suitable measuring devices installed in the reaction vessel and / or by analyzes on samples taken. Suitable methods are known to the person skilled in the art. These are, for example, viscosity measurements, measurements of the NCO content, the refractive index, the OH content, gas chromatography (GC), nuclear magnetic resonance spectroscopy (NMR), infrared spectroscopy (IR) and near near-infrared spectroscopy (NIR).
• the NCO content of the mixture is determined titrimetrically.
• the urethanization of components A) and B) is continued until a complete conversion of the OH groups of the compounds of component A) is reached.
• the first possibility involves the addition of a further NCO-reactive component, which in a subsequent Reaction step is reacted with the remaining NCO groups.
• a further NCO-reactive component which in a subsequent Reaction step is reacted with the remaining NCO groups.
• These may be, for example, low molecular weight alcohols.
• the second possibility for the further reduction of the NCO content of the reaction product of components A) and B) is an allophanatization reaction.
• the remaining NCO groups are reacted with the previously formed urethane groups, preferably by adding a catalyst which promotes allophanatization.
• the alkoxysilane-group-modified polyurethanes of the invention generally have a viscosity of less than 200,000 mPas, preferably less than 100,000 mPas, in each case measured at 23 ° C.
• the compounds according to the invention are very suitable as binders for the preparation of low-modulus elastic sealants, preferably for vehicle construction and construction. These adhesives crosslink under the action of atmospheric moisture via a silanol polycondensation.
• the polymers obtained by this crosslinking are also an object of the present invention, their chemical and physical properties are responsible for the outstanding quality of the seals produced.
• the polyurethanes of the invention modified with alkoxysilane groups may be used together with the customary fillers, pigments, plasticizers, drying agents, additives, light stabilizers, antioxidants, thixotropic agents, catalysts, adhesion promoters and optionally other auxiliaries and additives are formulated by known methods of sealant production.
• Suitable basic fillers used are precipitated or ground chalks, metal oxides, sulfates, silicates, hydroxides, carbonates and bicarbonates. Further fillers are e.g. reinforcing and non-reinforcing fillers such as carbon black, precipitated silicas, fumed silicas, quartz powder or various fibers. Both the basic fillers and the further reinforcing or non-reinforcing fillers may optionally be surface-modified. Particular preference is given to using as basic fillers precipitated or ground chalks and pyrogenic silicic acids. Mixtures of fillers can also be used.
• plasticizers examples include phthalic acid esters, adipic acid esters, alkylsulfonic acid esters of phenol or phosphoric acid esters. Long-chain hydrocarbons, polyethers and vegetable oils can also be used as plasticizers. Due to the special properties of the polymer according to the invention, the proportion of plasticizer in the sealant formulation can be limited to ⁇ 30% by weight, preferably to ⁇ 25% by weight, particularly preferably to ⁇ 20% by weight.
• thixotropic agents which may be mentioned are pyrogenic silicic acids, polyamides, hydrogenated castor oil derived products or else polyvinyl chloride.
• suitable catalysts for curing it is possible to use all organometallic compounds and amine catalysts which, as is known, promote silane polycondensation.
• Particularly suitable organometallic compounds are especially compounds of tin and titanium.
• Preferred tin compounds are, for example: dibutyltin diacetate, dibutyltin dilaurate, dioctyltin methyl acetate and tin carboxylates such as stannous octoate or dibutyltin-bis-acetoacetonate.
• the said tin catalysts may optionally be used in combination with amine catalysts such as aminosilanes or 1,4-diazabicyclo [2.2.2] octane.
• amine catalysts such as aminosilanes or 1,4-diazabicyclo [2.2.2] octane.
• Preferred titanium compounds are, for example, alkyl titanates, such as diisobutyl-bisacetoacetic acid ethyl ester titanate.
• amine catalysts are particularly suitable those having a particularly high base strength, such as amines with amidine structure.
• Preferred amine catalysts are therefore, for example, l, 8-diazabicyclo [5.4.0] undec-7-ene or 1, 5-diazabicyclo [4.3.0] non-5-ene.
• drying agents include alkoxysilyl compounds such as vinyl trimethoxysilane, methyltrimethoxysilane, z '-Butyltrimethoxysilan, Hexadecyltrimeth- oxysilane.
• Adhesion promoters used are the known functional silanes, such as, for example, amino silanes, epoxysilanes and / or mercaptosilanes or mixtures of functional silanes.
• the viscosity measurements were carried out according to ISO / DIS 3219: 1990 at a constant temperature of 23 ° C. and a constant shear rate of 250 / sec using a Physica MCR disk-viscous rotational viscometer (Anton Paar Germany GmbH, Ostfildern, DE) of the measuring cone CP 25-1 (25mm diameter, 1 ° cone angle).
• RT The ambient temperature of 23 ° C prevailing at the time of the experiment.
• Example 1 (according to the invention):
• a film is applied to a previously cleaned with ethyl acetate glass plate and immediately loaded into the Drying Recorder.
• the needle is loaded with 10 g and moves over a period of 24 hours over a distance of 35 cm.
• the Drying Recorder is located in a climate room at 23 ° C and 50% rel. Humidity.
• the skin-forming time is the time at which the permanent trace of the needle disappears from the film.
• the binder with filler Socal ® UiS 2
• plasticizer DINP Jayfiex TM
• desiccant Desiccant
• the adhesion promoter (Dynasylan ® 1146) is added and stirred in within 5 min at 1000 U / min.
• the catalyst (Lupragen ® N700) is stirred at 1000 U / min and, finally, the finished mixture in vacuo tet deaerated.
• the level of plasticizer was classified below 20% by weight:
• the sealant obtained with this low-softening formulation exhibits the following mechanical properties:

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Sealing Material Composition (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Polyethers (AREA)
• Adhesives Or Adhesive Processes (AREA)

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• 2009
  • 2009-12-09 DE DE200910057599 patent/DE102009057599A1/de not_active Withdrawn
• 2010
  • 2010-12-06 WO PCT/EP2010/068952 patent/WO2011069954A1/de active Application Filing
  • 2010-12-06 US US13/514,742 patent/US8981030B2/en active Active
  • 2010-12-06 EP EP10790748A patent/EP2510029A1/de not_active Withdrawn
  • 2010-12-06 CN CN2010800562013A patent/CN102741308A/zh active Pending
  • 2010-12-06 JP JP2012542488A patent/JP2013513674A/ja active Pending

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