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
  • C08G18/08—Processes
  • C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
  • C08G18/12—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step using two or more compounds having active hydrogen in the first polymerisation 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
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/80—Masked polyisocyanates
  • C08G18/8061—Masked polyisocyanates masked with compounds having only one group containing active hydrogen
  • C08G18/8083—Masked polyisocyanates masked with compounds having only one group containing active hydrogen with compounds containing at least one heteroatom other than oxygen or nitrogen
  • C08G18/809—Masked polyisocyanates masked with compounds having only one group containing active hydrogen with compounds containing at least one heteroatom other than oxygen or nitrogen 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
  • C08G2170/00—Compositions for adhesives
  • C08G2170/20—Compositions for hot melt adhesives
• • 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 isocyanato-functional silanes and their use as adhesion promoters for reactive one- or two-component adhesives / sealants, reactive hot-melt adhesives or solvent-containing polyurethane adhesives.
• Reactive polyurethane adhesives / sealants in particular one-component moisture-curing systems, generally contain polymers with urethane groups, possibly urea groups and reactive isocyanate groups, which are liquid at room temperature.
• these compositions are solvent-free and very highly viscous and / or pasty, they are processed at room temperature or at a slightly elevated temperature between about 50 ° C and about 100 ° C.
• Reactive, one-component, moisture-curing polyurethane hotmelt adhesives are moisture-curing or moisture-crosslinking adhesives that are solid at room temperature and are applied in the form of their melt as an adhesive, and whose polymer components contain urethane groups and reactive isocyanate groups. By cooling this melt after the application and joining of the substrate parts to be joined, a rapid physical setting of the hot melt adhesive takes place first by its solidification. This is followed by a chemical reaction of the isocyanate groups still present with moisture from the environment to form a crosslinked, infusible adhesive.
• Reactive hot melt adhesives based on isocyanate-terminated polyurethane prepolymers are e.g. at H.F. Huber and H. Müller in "Shaping Reactive Hotmelts Using LMW Copolyesters", Adhesives Age, November 1987, pages 32 to 35.
• Laminating adhesives can either be constructed similarly to the reactive hot-melt adhesives or they are applied as one-component systems from the solution in organic solvents, a further embodiment exists from two-component solvent-containing or solvent-free systems in which the polymeric components of one component contain urethane groups and reactive isocyanate groups and, in the two-component systems, the second component contains polymers or oligomers with hydroxyl groups, amino groups, epoxy groups and / or carboxyl groups. In these two-component systems, the component containing isocyanate groups and the second component are mixed immediately before application, normally with the aid of a mixing and metering system.
• Reactive polyurethane adhesives / sealants are characterized by a very high performance profile. Therefore, new applications for these adhesives / sealants have been increasingly opened up in recent years. Compositions for such adhesives and / or sealants are already known from a large number of patent applications and other publications.
• organofunctional silanes such as e.g. 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane,
• organofunctional silanes of the aforementioned type to polyurethane adhesives and sealants definitely shows the desired adhesion-promoting effect, this procedure has a number of serious disadvantages.
• the addition of the above-mentioned isocyanato-functional silanes is questionable for occupational hygiene reasons, particularly in the case of hotly applied polyurethane systems, since these can be classified as very toxic when inhaled and can cause bronchial asthma when inhaled, that is to say they have a sensitizing effect on the respiratory tract.
• the epoxy-functional, methacrylic-functional and vinyl-functional alkoxysilanes have only a very limited activity in polyurethane compositions, since they cannot be incorporated into the polyurethane structure of the reactive polyurethanes.
• the mercapto-functional alkoxysilanes are reactive towards isocyanate groups and are thus incorporated into the polyurethane structure, but because of their monofunctionality they have a chain-terminating effect, so that these compounds have a negative influence on the strength of such adhesives, especially when larger amounts of adhesion-promoting substance have to be added , Because of their high functionality and basicity, the use of amino-functional alkoxysilanes often leads to stability problems and to gelation during the storage and handling of polyurethane adhesive systems.
• JP-10114813 A describes a liquid polyurethane adhesive composition containing a polyurethane prepolymer with isocyanate end groups and an adduct of an aminosilane compound or a mercaptosilane compound with an organic polyisocyanate and the addition of an epoxysilane compound.
• These compositions are said to be used as adhesives, sealants or paints and to have good adhesion to metals, glass, concrete and the like, and to be stable in storage and to be suitable for the construction industry. No other applications can be found in this document.
• JP-2000128949 A describes one-component liquid polyurethane compositions which are moisture-curing and which contain a polyurethane prepolymer and a silane compound, the silane compound should have 1, 5 or more isocyanate groups and 1, 5 or more hydrolyzable alkoxy groups per molecule.
• the silane compound is to be produced by adding a polyisocyanate with 3 or more Isocyanate groups per molecule with an alkoxysilane with secondary amino groups and / or a silane compound with a lysine structure, prepared by adding lysine diisocyanate with 2 or 3 isocyanate groups with an aminoalkoxysilane with secondary amino groups.
• These compositions are said to be suitable as sealing material for automotive applications or as coating compositions for the construction industry and to have good primer-free adhesion and curing properties and resistance to foaming.
• WO-9836007 A1 describes a polyurethane sealant composition for the bonding of panes in automobile manufacture.
• these compositions are said to contain an adduct of an isocyanate-reactive silane compound and a polyisocyanate.
• reaction products of 3-isocyanatomethyl-3,5,5-trimethycyclohexyl isocyanate (isophorone diisocyanate, IPDI) with amino-functional alkoxysilanes such as, for example, 3-aminopropyltriethoxysilane is also known.
• IPDI isophorone diisocyanate
• the advantage of these compositions is their low viscosity, but they cannot be prepared free of monomeric IPDI without great expense.
• Hot melt adhesive processing is hardly suitable from a toxicological point of view because of the high IPDI vapor pressure.
• the "difficultly volatile" polyisocyanate used to produce the isocyanato-functional silane according to the invention should have a substantially lower vapor pressure than the IPDI, ie the vapor pressure of the polyisocyanate should be less than 5 * 10 "5 hPa at 20 ° C.
• a non-volatile diisocyanate such as dimer fatty acid diisocyanate or 1, 12-dodecane diisocyanate or polyisocyanates with higher functionality and / or higher molecular weight, preferably have, the polyisocyanates with a molecular weight below about 800 3 isocyanate groups per molecule.
• the organofunctional silanes suitable for the reaction should have a functionality of less than or equal to 1.3, preferably less than or equal to 1.2, compared to the polyisocyanate.
• Suitable NCO-reactive groups for the organofunctional silane are hydroxyl groups, preferably mercapto groups and, particularly preferably, secondary amino groups.
• the isocyanurate of hexamethylene diisocyanate is suitable as the polyisocyanate to be used, e.g. Known under the trade name "Desmodur N 3300" from Bayer, the isocyanuration products of other aliphatic and cycloaliphatic diisocyanates such as e.g. the IPDI, e.g. Known under the trade name "IPDI-T 1890" from Degussa-Huls or also adducts of aliphatic or cycloaliphatic isocyanates with low molecular weight triols or with diols with a molecular weight below 2000, preferably below 1000.
• IPDI e.g. Known under the trade name "IPDI-T 1890” from Degussa-Huls or also adducts of aliphatic or cycloaliphatic isocyanates with low molecular weight triols or with diols with a molecular weight
• Such adducts are high molecular weight polyisocyanates, their use WO 01/40342 describes the starting material for adhesive and sealant binders; the high molecular weight diisocyanates described there are very well suited for reaction with the above-mentioned organofunctional silanes.
• the aforementioned isocyanurates or high molecular weight polyisocyanates generally still contain traces of the starting isocyanates used for the synthesis, the main product fulfills the criterion of low volatility according to the invention.
• the details of the vapor pressure given above for the isocyanurates, adducts and high molecular weight diisocyanates therefore relate to the main product and not to the impurities.
• Suitable cycloaliphatic polyisocyanates are the hydrogenation products of aromatic diisocyanates such as 4,4'-dicyclohexylmethane diisocyanate (H12MDI), 1-isocyanatomethyl-3-isocyanato-1, 5,5-trimethylcyclohexane (isophorone diisocyanate, IPDI) , Cyclohexane-1,4-diisocyanate, hydrogenated xylylene diisocyanate (H ⁇ XDI), 1-methyl-2,4-diisocyanato-cyclohexane, m- or p-tetramethylxylene diisocyanate (m-TMXDI, p-TMXDI) and dimer fatty acid diisocyanate.
• aromatic diisocyanates such as 4,4'-dicyclohexylmethane diisocyanate (H12MDI), 1-isocyanatomethyl-3-isocyanato-1, 5,5-
• aliphatic polyisocyanates are tetramethoxybutane-1,4-diisocyanate, butane-1,4-diisocyanate, hexane-1,6-diisocyanate (HDI), 1,6- Diisocyanato-2,2,4-trimethylhexane, 1,6-diisocyanato-2,4,4-trimethylhexane, lysine diisocyanate and 1, 12-dodecane diisocyanate (C12DI).
• HDI hexane-1,6-diisocyanate
• C12DI 1, 12-dodecane diisocyanate
• Trimethylolpropane and glycerol are particularly suitable as triols, and either ⁇ , ⁇ -alkanediols or polyethylene glycols, polypropylene glycols or polyester diols with a molecular weight below 2000, preferably below 1000, are suitable as diols.
• the organofunctional silanes which are particularly suitable are 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylalkyldiethoxysilane and in particular N- (n-butyl) -3-aminopropyltrimethoxysilane, N- (n-butyl) -3- aminopropyltriethoxysilane, the N- (n-butyl) -3-aminopropylalkoxydiethoxysilane and the bis- (3-triethoxysilylpropyl-) amine and the corresponding alkyldiethoxysilyl derivative of the latter silane.
• mixtures can also be used, but these should contain at least 70% by weight, preferably more than 80% by weight, of secondary aminosilane.
• the isocyanato-functional silanes according to the invention are particularly suitable as adhesion-promoting additives for hot-melt polyurethane adhesives since they have no volatile and in particular no toxic volatile constituents, but they can also be used as adhesion-promoting additives in sealants, laminating adhesives and coating compositions. In particular, they are suitable for those applications in which no complex ventilation devices are available, i.e. for example in the trades and consumer area. Their addition to the adhesives enables adhesive formulations with a wide range of adhesion, including substrates that are difficult to bond, such as metals, mineral substrates or glass, as well as a variety of plastics.
• Polyurethane hot-melt adhesive compositions which contain the silane additives according to the invention have high thermal stability and viscosity stability in the melt.
• the adhesive or sealant compositions usually contain 0.1 to about 5% by weight, preferably between 0.5 and 2% by weight, of the isocyanato-functional silane according to the invention.
• Example 3 The procedure was analogous to Example 3, but the silane coupling agent from Example 2 was used. The viscosity rose by 450% after 6 hours at 130 ° C.
• substrates were selected which are difficult to bond with conventional polyurethane hotmelt adhesives in a manner resistant to aging.
• test specimens were subjected to a four-day climate change test, as is customary in the automotive industry (in accordance with the VW P 1200 standard).

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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)
• Adhesives Or Adhesive Processes (AREA)
• Polyurethanes Or Polyureas (AREA)
• Sealing Material Composition (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Related Child Applications (1)

Publications (1)

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Cited By (13)

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Citations (9)

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• 2001
  • 2001-12-20 DE DE10162642A patent/DE10162642A1/de not_active Ceased
• 2002
  • 2002-12-11 WO PCT/EP2002/014057 patent/WO2003054049A1/de not_active Ceased
  • 2002-12-11 AT AT02787933T patent/ATE444322T1/de not_active IP Right Cessation
  • 2002-12-11 ES ES02787933T patent/ES2331235T3/es not_active Expired - Lifetime
  • 2002-12-11 DE DE50213893T patent/DE50213893D1/de not_active Expired - Lifetime
  • 2002-12-11 AU AU2002352240A patent/AU2002352240A1/en not_active Abandoned
  • 2002-12-11 EP EP02787933A patent/EP1456274B1/de not_active Expired - Lifetime
  • 2002-12-11 JP JP2003554762A patent/JP4159472B2/ja not_active Expired - Fee Related
• 2004
  • 2004-06-17 US US10/870,344 patent/US20050032974A1/en not_active Abandoned

Patent Citations (9)

Non-Patent Citations (1)

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