Compositions of reactive hot melt adhesives based on organic polymers with alpha-silane terminal groups

Abstract

The present invention relates to reactive hot-melt adhesive compositions containing, based on the total weight of the composition: a) 3% to 49% by weight of at least one alpha-silane-terminated organic polymer; b) 1% to less than 20% by weight, preferably 1% to 10% by weight, of at least one acrylate resin-based polymer; c) 1% to 20% by weight, preferably 1% to 10% by weight, of at least one chemical compound that is liquid at least at 100°C and in which the acrylate resin-based polymer dissolves at least at 150°C; d) 0.001% to 5% by weight, preferably 0.001% to 2% by weight, of at least one oligomeric silane containing one or more amino groups. The invention also relates to processes for preparing said composition and to a process for laminating surfaces using said composition.

Description

[0001] The present invention relates to reactive hot melt adhesive compositions. The invention further relates to methods for their production and to a method for surface lamination using the composition.

[0002] Reactive hot melt adhesives occupy a large market share due to their advantages, such as a short setting time, high initial strength and resistance, are used in a variety of applications and have replaced solvent-based adhesives in many applications (see e.g. Bodo Müller, Walter Rath, Formulation of Adhesives and Sealants, Vincentz Network; 1st edition, December 2004).

[0003] The most important representative among reactive hot melt adhesives are moisture-curing polyurethanes based on methylene diphenyl diisocyanate (MDI). Due to its sensitizing effects, the handling of monomeric MDI has recently been restricted under REACH, as outlined in EU Regulation 2020 / 1149.

[0004] Patent literature describes processes for the production of low-monomer reactive polyurethane hot melt adhesives based on MDI (see, for example, WO 03 / 055929 A1, WO 01 / 40342 A1, WO 03 / 033562 A1, WO 03 / 006521 A1).

[0005] Furthermore, processes for the silanization of polyurethane hot melt adhesives are described, representing an isocyanate-free alternative. In this process, moisture-curing di- or trialkoxysilane units are generally introduced. One method of preparation involves the reaction of the isocyanate groups of reactive polyurethane hot melt adhesives with secondary aminosilanes (e.g., WO 2004 / 005420 A1). To accelerate the crosslinking reaction, aminosilanes, tin accelerators, and / or strong nitrogen bases (e.g., 1,8-diazabicyclo[5.4.0]undec-7-ene) are typically used. A disadvantage of this process is that these accelerators can simultaneously promote the hydrolysis of the ester units usually present in reactive polyurethane hot melt adhesives. Furthermore, the formulations obtained in this way are generally no longer sufficiently stable for processing on roller coating machines.Reactive hot melt adhesives are frequently processed using roller coating machines and are often exposed to ambient humidity. The formulations must therefore be sufficiently stable and, even during short-term machine downtime, must not react with the ambient humidity to such an extent that a significant increase in the applied quantity and stringing occur, the latter negatively impacting the applied finish.

[0006] Stable hot melt adhesive formulations based on silane-terminated polymers represent an interesting class of adhesives. Furthermore, such silane-functionalized adhesives exhibit a broad adhesion spectrum, which can be an advantage compared to isocyanate-curing systems, for example. Since a silane group in silane-terminated polymers can typically undergo two to three condensation reactions, a higher crosslinking density is also possible compared to structurally similar isocyanate-based binders. It would be advantageous if these adhesives could be reliably processed at high temperatures, sometimes using rollers, and exhibited the high initial tack typical for this application, as well as chemical curing acceptable for industrial applications.

[0007] In the course of this development, two approaches were pursued for the production of silane-based formulations. Besides the silanization of existing reactive polyurethane hot melt adhesives described above, in which their isocyanate groups are chemically reacted with secondary aminosilanes, the second approach involves the formulation of commercially available silane binders with crystalline or amorphous resins to achieve high initial adhesion. For example, WO 2007 / 074143 A1 describes moisture-curing hot melt adhesive compositions using silane-functionalized polyurethane prepolymers.

[0008] WO 2013 / 026654 A1 describes crosslinkable compounds based on organyloxysilane-terminated polymers. As in DE 10 2013 213 835 A1, mixtures of alpha-silanes, such as Geniosil® < STP-E10, and silicone resins are described.

[0009] WO 2011 / 087741 A2 describes adhesives for binding books and related objects and the manufacture of such adhesives using silane-modified liquid polymers. In particular, the adhesives are to have a reduced content of monomeric diisocyanates or no content of monomeric diisocyanates.

[0010] In both cases, the initial result was unsatisfactory. The formulations obtained had insufficient initial adhesion, were not roller-stable, or cured too slowly.

[0011] WO2014 / 018349A1 discloses a reactive hot melt adhesive composition comprising, based on the total weight of the composition, a) 40 wt% of a silane-terminated organic polyether; b) 20 wt% of an acrylate resin-based polymer; c) 6 wt% of a tackifier KE-100; and d) 0.1 wt% of a low molecular weight amino group-containing silane Silquest A1110.

[0012] Polyester and polyacrylate resins are among the materials considered for improving initial adhesion. Polyester resins are susceptible to degradation through hydrolysis, which is catalyzed by accelerators typical of silane adhesives, such as aminosilanes. Suitable crystalline polyacrylate resins, on the other hand, must be melted at very high temperatures (approximately 150 °C). However, commercially available polyether-based silane binders are not stable at these temperatures.

[0013] One object of the present invention was therefore to provide reactive hot melt adhesive compositions that do not have the aforementioned disadvantages or at least have them to a lesser extent.

[0014] The problem was solved by a reactive hot melt adhesive composition based on the total weight of the composition containing a) 3 wt.% to 49 wt.% of at least one alpha-silane-terminated organic polymer; b) 1 wt.% to less than 20 wt.%, preferably 1 wt.% to 10 wt.%, of at least one acrylate resin-based polymer; c) 1 wt.% to 20 wt.%, preferably 1 wt.% to 10 wt.%, of at least one chemical compound that is liquid at least at 100 °C, in which the at least one acrylate resin-based polymer dissolves at least at 150 °C; d) 0.001 wt.% to 5 wt.%, preferably 0.001 wt.% to 2 wt.%, of at least one oligomeric silane containing one or more amino groups.

[0015] The problem was also solved by a method for producing a reactive hot melt adhesive composition according to the present invention comprising the steps (a) Adding at least one acrylate resin-based polymer to at least one chemical compound that is liquid at least at 100 °C, in which the at least one acrylate resin-based polymer dissolves at least at 150 °C, or adding it to a mixture containing the at least one chemical compound at a temperature in the range of 130 °C to 170 °C; (b) Cooling the mixture to a temperature in the range of 80 °C to 120 °C; (c) Adding at least one alpha-silane-terminated organic polymer to the cooled mixture; (d) Adding at least one oligomeric silane containing one or more amino groups, obtaining a reactive hot melt adhesive composition according to the present invention.

[0016] The problem was also solved by a surface lamination method comprising the step of applying a reactive hot melt adhesive composition according to the present invention to a substrate using an application roller.

[0017] The requirement for a roller-stable adhesive at processing temperatures of 100-120 °C with an acceptable curing rate was surprisingly achieved using binders based on silane-terminated polymers (so-called alpha-silanes). This involved the use of an acrylate resin-based polymer that can be dissolved at least at 150 °C by means of a chemical compound that is liquid at least at 100 °C, as well as by means of at least one oligomeric silane containing one or more amino groups. In this way, hydrolysis-stable formulations with satisfactory initial adhesion could be produced. Furthermore, the reactive hot-melt adhesive compositions according to the invention exhibit high crosslinking densities, which can explain good plasticizer resistance.

[0018] Accordingly, the reactive hot melt adhesive composition according to the present invention is a low-viscosity, largely roller-stable, moisture-curing adhesive formulation based on alpha-silane-terminated polymers, which exhibits sufficiently high initial adhesion at room temperature for surface lamination and cures chemically quickly enough. During curing, alcohol (especially methanol, optionally also ethanol) is cleaved off by a condensation reaction, forming siloxane groups.

[0019] More precisely, it is known that in alpha-silanes, a two-stage condensation reaction of alkoxysilanes occurs largely autocatalytically via the donor atom (e.g., a nitrogen atom) located in the alpha position relative to the silicon atom (alpha effect). The reactive hot-melt adhesive compositions according to the present invention are accelerated by aminosilanes and do not require the use of further co-catalysts such as organotin compounds or diazabicycloundecene. Surprisingly, it has been shown in the course of this invention that formulations with an alpha-silane are roller-stable for a period of approximately 30–60 minutes at 100 °C without enclosure under typical room conditions (room temperature approximately 20–23 °C, relative humidity approximately 30–65%) and cure sufficiently quickly despite the moderate acceleration and without the use of further co-catalysts.

[0020] The present invention relates to a reactive hot melt adhesive composition. The term "hot melt adhesive" describes an adhesive that is solid at room temperature or has a high shear modulus and is in liquid form at elevated temperatures, usually between 100 °C and 120 °C. Hot melt adhesives are applied in liquid form and then solidify, so that they are again in solid form at room temperature or have a high shear modulus. Furthermore, "reactive" hot melt adhesives are characterized by their ability to crosslink through chemical reactions. This usually involves a reaction with water, which, for example, comes into contact with the hot melt adhesive as atmospheric moisture. These are therefore referred to as moisture-curing. This also applies to the reactive hot melt adhesive compositions of the present invention.

[0021] The reactive hot melt adhesive composition of the present invention is also liquid at a temperature of 100 °C to 120 °C. It typically exhibits a viscosity of 4000 mPas to 12000 mPas. Preferably, the reactive hot melt adhesive composition according to the invention is isocyanate-free.

[0022] The reactive hot melt adhesive composition according to the present invention comprises components a) to d). Furthermore, the composition according to the invention may include additional components. Accordingly, one embodiment of the present invention relates to a reactive hot melt adhesive composition consisting of components a) to d). Another embodiment of the present invention relates to a reactive hot melt adhesive composition comprising, in addition to components a) to d), one or more, such as two, three, four, five, six, seven, eight, nine, or ten components.

[0023] Component a) of the reactive hot melt adhesive composition according to the invention comprises at least one alpha-silane-terminated organic polymer. Accordingly, the reactive hot melt adhesive composition according to the present invention can comprise one alpha-silane-terminated polymer or several, such as two, three, or four, polymers. It is clear to those skilled in the art that polymers are not pure substances, but rather occur as a mixture with a characteristic composition due to the manufacturing process, and that therefore "one polymer" is a simplified term for this mixture.

[0024] Alpha-silane-terminated organic polymers are known to those skilled in the art and can be obtained commercially, for example. Wacker Chemie AG, Munich (DE), markets such alpha-silane-modified polymers under the name Geniosil®<, such as Geniosil®< STP-E10 or Geniosil®< XB 502.

[0025] Alpha-silanes are characterized by the so-called alpha effect. In this effect, the proximity of an electronegative donor, such as nitrogen or oxygen, in the alpha position to the silicon atom—for example, separated only by a methylene bridge—activates alkoxy groups on the silicon atom. These groups are thus more reactive towards nucleophiles such as water. This, in turn, leads to accelerated hydrolysis without the need for, for example, tin-containing catalysts. The hydrolysis of the silanes can proceed via crosslinking to siloxanes. In this respect, the reactive hot-melt adhesive compositions of the present invention represent alpha-silane-terminated hot-melt adhesives that can react to form siloxanes via moisture crosslinking.

[0026] Preferably, the at least one alpha-silane-terminated organic polymer is a polymer having a plurality of end groups of the formula *-XC(=O)-N(R)-C(R 1< R 2< )-Si(R 3< ) a (OR 4< ) 3-a, wherein X stands for O or N(R); each R independently stands for hydrogen or a hydrocarbon residue with 1 to 20 carbon atoms; R 1< and R 2< independently stand for hydrogen or a hydrocarbon residue with 1 to 20 carbon atoms; R 3< and R 4< independently stand for a hydrocarbon residue with 1 to 20 carbon atoms; a stands for 0, 1 or 2 and "*" denotes the bond for attachment to the polymer.

[0027] More preferably, R represents hydrogen or an alkyl group comprising 1 to 4 carbon atoms, wherein the alkyl group may be straight-chain or branched. More preferably, R is H, methyl, or ethyl, and more preferably, hydrogen or methyl.

[0028] Hydrogen is particularly preferred in R.

[0029] More preferably, R1< and R2< are the same. Further preferably, R1< and R2< are hydrogen or an alkyl group having 1 to 4 carbon atoms, the alkyl group being straight-chain or branched. More preferably, R1< and R2< are H, methyl, or ethyl, and more preferably, hydrogen or methyl.

[0030] R1< and R2< hydrogen are particularly preferred.

[0031] More preferably, R3< and R4< are the same. Further preferably, R3< and R4< are an alkyl group having 1 to 4 carbon atoms, wherein the alkyl group can be straight-chain or branched. More preferably, R3< and R4< are methyl or ethyl.

[0032] Particularly preferred are R 3< and R 4< Methyl.

[0033] Preferably a = 1 or 2, more preferably a = 1.

[0034] An exemplary at least one alpha-silane-terminated organic polymer is a polymer that has a variety of end groups of the formula *-OC(=O)-NH-CH 2 -Si(CH 3 )(OCH 3 ) 2.

[0035] The numerous end groups described above terminate an organic polymer. Preferably, the organic polymer is a polyoxyalkylene, a hydrocarbon polymer, a polyurethane, a polyester, a polyamide, a polyacrylate, a polymethacrylate, or a polycarbonate. Polyoxyalkylene is preferred. Preferably, the organic polymer contains no further silane groups beyond the end groups listed above.

[0036] Preferred polyoxyalkylenes are polypropylenes, for example with a number-averaged molecular weight in the range of 5000 g / mol to 50,000 g / mol, more preferably from 7500 g / mol to 30,000 g / mol, more preferably from 10,000 g / mol to 15,000 g / mol.

[0037] Component a) comprises a proportion of 3 wt.% to 49 wt.% based on the total weight of the composition. Preferably, the proportion is 3 to 20 wt.%, more preferably 5 to 20 wt.%.

[0038] Furthermore, the reactive hot melt adhesive composition according to the present invention comprises at least one acrylate resin-based polymer as component b). Accordingly, the composition according to the invention can comprise one or more, such as two, three, or four, acrylate-based polymers. It is clear to those skilled in the art that polymers are not pure substances, but rather occur as a mixture with a characteristic composition due to the manufacturing process, and that therefore "one polymer" is a simplified term for this mixture. Preferably, component b) consists only of one acrylate resin-based polymer.

[0039] If component a) is also an acrylate resin-based polymer as an organic polymer, components a) and b) can be distinguished by the fact that component b) does not have any alpha-silane terminated groups.

[0040] Preferably, the acrylate-based polymer is a homoacrylate, a homomethacrylate, a copolymer of at least two different acrylates, a copolymer of at least two different methacrylates, or a copolymer of at least one acrylate and at least one methacrylate.

[0041] The proportion of component b) is 1 wt.% to 20 wt.% based on the total weight of the reactive hot melt adhesive composition according to the invention. Preferably, the proportion is 1 wt.% to 10 wt.%. More preferably, the proportion is 8 wt.% to 9 wt.%.

[0042] Component b) serves to achieve sufficient initial adhesion. A copolymer consisting of methyl methacrylate and n-butyl methacrylate is particularly preferred for this purpose.

[0043] The at least one acrylate resin-based polymer can be crystalline, partially crystalline, or amorphous and thus has a melting point, melting range (here, the lower temperature point is considered the melting point), or a glass transition temperature. Preferably, this temperature is in the range of 30 °C to 300 °C, more preferably in the range of 30 °C to 250 °C, further more preferably in the range of 30 °C to 150 °C, more preferably in the range of 30 °C to 80 °C, more preferably in the range of 40 °C to 75 °C, more preferably in the range of 50 °C and 70 °C, and particularly at 60 °C. Preferably, the at least one acrylate resin-based polymer is amorphous, so that the specified temperature values ​​then refer to its glass transition temperature.

[0044] Preferably, the at least one acrylate resin-based polymer has a mean weight-averaged molecular weight in the range of 10,000 g / mol to 150,000 g / mol. More preferably is a range of 25,000 g / mol to 125,000 g / mol, further more preferably a range of 30,000 g / mol to 110,000 g / mol, further more preferably a range of 35,000 g / mol to 100,000 g / mol, further more preferably a range of 40,000 g / mol to 90,000 g / mol, further more preferably a range of 45,000 g / mol to 80,000 g / mol, further more preferably a range of 50,000 g / mol to 70,000 g / mol, and in particular, the mean weight-averaged molecular weight is 60,000 g / mol.

[0045] As component c), the reactive hot melt adhesive composition contains at least one chemical compound that is liquid at least at 100 °C, in which at least one acrylate resin-based polymer dissolves at least at 150 °C.

[0046] Within the scope of the present invention, "dissolved at least at 150 °C" refers to the dissolution of solid acrylic resin-based polymer. However, dissolution can also occur at lower temperatures. If the melting point, melting range, or glass transition temperature is below 150 °C, "dissolved" refers to the formation of a single-phase mixture containing the chemical compound.

[0047] Component c) can comprise one or more chemical compounds, such as two, three, or four. Advantageously, it comprises only one compound. Component c) is different from components a) or b). Therefore, a compound is classified as component c) if it is capable of dissolving component b) at least at 150 °C within the limits of its possible proportions in the overall composition, while itself remaining liquid at least at 100 °C, and if it differs from components a) and b).

[0048] The proportion of component c) is 1 wt.% to 20 wt.% based on the total weight of the reactive hot melt adhesive composition according to the invention. Preferably, the proportion is 1 wt.% to 10 wt.%. More preferably, the proportion is 6 wt.%.

[0049] For a chemical compound to be effective, the only important requirement besides its solubility is that it exists as a liquid at least at 100 °C. Numerous compounds can be used, and a person skilled in the art can identify suitable ones through simple dissolution tests. The following are examples of compounds that can be used.

[0050] Advantageously, the at least one chemical compound that is liquid at least at 100 °C, in which at least one acrylate resin-based polymer dissolves at least at 150 °C, can be a plasticizer.

[0051] Examples of plasticizers are known in the prior art. Reference is made here to the examples listed in DIN EN ISO 1043-3 (2017-03).

[0052] Examples of plasticizers include: Alkylsulfonsäureester Diisooctylmaleat N-Butylbenzolsulfonamid Butyl- O -acetylrizinoleat Diisooctylphthalat Nonylundecyladipat Benzylbutylphthalat Diisooctylsebazat Nonylundecylphthalat Butylcyclohexylphthalat Diisooctylazelat Octyldecyladipat Butylnonylphthalat Diisopentylphthalat Octyldecylphthalat Benzyloctyladipat Di-2-Methyloxyethylphthalat n-Octyldecyltrimellitat Butyloctylphthalat Dimethylphthalat Paraffinöl Butylstearat Dimethylsebazat Polypropylenadipat Dibutyladipat Dinonylfumarat Polypropylensebazat Di-2-Butoxyethylphthalat Dinonylmaleat Sucroseoctaacetat Dibutylfumarat Di-n-octylphthalat Tributyl-O-acetylcitrat Dibutylmaleat Dinonylphthalat Tri-2-Butoxyethylphosphat Dibutylphthalat Dinonylsebazat Tributylphosphat Dibutylsebazat Dioctyladipat Trichlorethylphosphat Dibutylazelat Dioctylisophthalat Trikresylphosphat Dicyclohexylphthalat Dioctylphthalat Tri-2,3-dibrompropylphosphat Dicaprylphthalat Dioctylsebazat Tri-2,3-dichlorpropylphosphat Didecylphthalat Dioctylterephthalat Triethyl-o-acetylcitrat Diethylenglycoldibenzoat Dioctylazelat Tetrahydrofurfuryloleat Diethylphthalat Diphenylkresylphosphat Triheptyltrimellitat Diheptylphthalat Di-Propylenglycoldibenzoat Triisooctyltrimellitat Dihexylphthalat Diphenyloctylphosphat Trioctylphosphat Diisobutyladipat Diphenylphthalat Tetraoctylpyromellitat Diisobutylmaleat Diisotridecylphthalat Trioctyltrimellitat Diisobutylphthalat Diundecylphthalat Triphenylphosphat Diisodecyladipat Epoxidiertes Leinsamenöl Trixylylphosphat Diisodecylphthalat Epoxidiertes Sojabohnenöl 1,2-Cyclohexandicarbonsäurediisononylester Diisoheptylphthalat Glycerintriacetat Isodecylbenzoat Diisohexylphthalat Heptylnonylundecyladipat Diisononyladipat Heptylnonylundecylphthalat Diisononylphthalat Hexyloctyldecyladipat Diisooctyladipat Hexyloctyldecylphthalat

[0053] Such plasticizers are commercially available. An example is Hexamoll® DINCH from BASF SE, Ludwigshafen (DE). 1,2-Cyclohexanedicarboxylic acid diisononyl esters or isodecyl benzoate are preferred.

[0054] It is also possible that the at least one chemical compound, which is liquid at least at 100 °C and in which the at least one acrylate resin-based polymer dissolves at least at 150 °C, is a polyalkylene glycol. Preferred polyalkylene glycols are polyethylene glycol and polypropylene glycol, more preferably polypropylene glycol. Preferably, the polyalkylene glycol has a number-average molecular weight in the range of 500 g / mol to 5000 g / mol, more preferably in the range of 750 g / mol to 4000 g / mol, more preferably in the range of 1000 g / mol to 3000 g / mol; in particular, the number-average molecular weight is 2000 g / mol.

[0055] It is also possible that the at least one chemical compound, which is liquid at least at 100 °C and in which at least one acrylate-resin-based polymer dissolves at least at 150 °C, is an alkoxysilane. Alkoxysilanes are commercially available. For example, the one from Evonik Industries AG, Essen (Germany), marketed under the trade name Tegopac®, is a binder containing laterally crosslinking ethoxysilanes.

[0056] The reactive hot-melt adhesive composition according to the invention further comprises a component d), which contains at least one oligomeric silane containing one or more amino groups. Thus, component d) can comprise one or more, such as two, three, or four, such silanes. Preferably, component d) consists of only one component. Component d) differs from components a) to c) and is only considered part of component d) insofar as it cannot be considered one of components a) to c).

[0057] The oligomeric silane of component d) containing at least one or more amino groups preferably represents a mixture of amino group-containing alkoxy / hydroxy silanes and / or silanols as well as condensation and co-condensation products based thereon and preferably has a molecular weight of more than 500 g / mol.

[0058] Such oligomeric silanes containing one or more amino groups are commercially available, for example as Dynasylan®< 1146 from Evonik. These are described, for example, in DE 10 2007 040 802 A1. Accordingly, their preparation can be described as follows.

[0059] As already explained above, the oligomeric silane containing at least one or more amino groups is a mixture that can be obtained by... (A) at least one aminoalkylalkoxysilane of the general formula I NR' 2 [(CH 2 ) 2 NR'] x -Y-Si(R") n (OR) 3-n (I), wherein groups R, R' and R" are the same or different and each represent a hydrogen atom or a linear or branched alkyl group with 1 to 8 C atoms, Y is a bivalent alkylene group from the series -CH 2-, -(CH 2 ) 2-, -(CH 2 ) 3- or -[CH 2 CH(CH 3 )CH 2 ]-, x is equal to 0, 1 or 2 and n is equal to 0 or 1, or (B) at least one bis-silylated alkylamine of the general formula II (RO) 3-m (R") m Si-Y-[NR'(CH 2 ) 2 ] y NR'[(CH 2 ) 2 NR'] z -Y-Si(R") n (OR) 3-n (II), wherein groups R, R' and R" are the same or different and each represent a hydrogen atom or a linear or branched alkyl group with 1 to 8 C atoms, groups Y are the same or different and Y represents a bivalent alkylene group from the series -CH 2 -, -(CH 2 ) 2 -, -(CH 2 ) 3 - or -[CH 2 CH(CH 3 )CH 2 ]-,y and z are independently equal to 0, 1 or 2, and m and n are independently equal to 0 or 1, or (C) at least one tris-silylated alkylamine of general formula III N[-Y-Si(R") n (OR) 3-n ] 3 (III), wherein groups R and R" are the same or different and each represent a hydrogen atom or a linear or branched alkyl group with 1 to 8 carbon atoms, Y is independently a bivalent alkylene group from the series -CH 2-, -(CH 2 ) 2-, -(CH 2 ) 3- or -[CH 2 CH(CH 3 )CH 2 ]- and n is independently equal to 0 or 1, or (D) at least two of the aforementioned silylated alkylamines of general formula I, II and III are hydrolyzed and condensed or cocondensed with a defined amount of water and optionally with the addition of an acid, and the free alcohol is substantially removed from the System removed.

[0060] Here, mono-silylated amines are defined as those of formula I. Oligo-silylated amines are defined in particular as those bearing two or more silyl groups on an amino group or alkylamine, for example, according to formula II (bis-silylated) or formula III (tris-silylated), and / or corresponding compounds, which may also exist in cyclized form.

[0061] In the preparation of the mixture, the following are preferably used as aminoalkylalkoxysilanes of the general formula I: H 2 N(CH 2 ) 3 Si(OCH 3 ) 3 (AMMO), H 2 N(CH 2 ) 3 Si(OC 2 H 5 ) 3 (AMEO), H 2 N(CH 2 ) 2 NH(CH 2 ) 3 Si(OCH 3 ) 3 (DAMO), H 2 N(CH 2 ) 2 NH(CH 2 ) 2 NH(CH 2 ) 3 Si(OCH 3 ) 3 (TRIAMO), and possibly corresponding cyclic compounds.

[0062] The preferred compounds according to formula II are (H 3 CO) 3 Si(CH 2 ) 3 NH(CH 2 ) 3 Si(OCH 3 ) 3 (Bis-AMMO), (H 5 C 2 O) 3 Si(CH 2 ) 3 NH(CH 2 ) 3 Si(OC 2 H 5 ) 3 (Bis-AMEO), (H 3 CO) 3 Si(CH 2 ) 3 NH(CH2)2 3 ) 3 (Bis-TRIAMO), as well as compounds according to formula III N[CH 2 ) 3 Si(OCH 3 ) 3 ] 3 (Tris-AMMO), N[CH 2 ) 3 Si(OC 2 H 5 ) 3 ] 3 (Tris-AMEO).

[0063] For the preparation of the mixture, at least one component (A) is preferably selected from the series AMMO, AMEO, DAMO, TRIAMO, 3-(N-Alkylamino)propyltrialkoxysilane, where alkyl means methyl, ethyl, n-propyl or n-butyl and alkoxy means methoxy or ethoxy, a preferred selection of component (B) can be from the series Bis-AMMO, Bis-AMEO, Bis-DAMO and component (C) from the series Tris-AMMO, Tris-AMEO.

[0064] Mixtures containing compounds of general formulas I, II, and / or III can also be advantageously used to prepare the mixture. Such usable mixtures can also contain so-called ancondensation products of said aminoalkoxysilanes. Ancondensation products or reaction products of aminoalkoxysilanes of general formulas I, II, and / or III are suitably understood to be dimeric, trimeric, tetrameric, or higher oligomeric products that generally arise from condensation or cocondensation and / or pre-hydrolysis of the respective monomers with elimination of alcohol. In corresponding condensates or co-condensates, the reactant components are thus linked via Si-O-Si bonds. It is also known that a cycle opens upon hydrolysis or alcoholysis, yielding the corresponding aminoalkylalkoxysilane or silanol. Likewise, compounds of general formula II can be obtained in cyclic or...They are in bicyclic form and are used as such.

[0065] According to chemical understanding, the reaction essentially produces a mixture of amino group-containing alkoxy / hydroxy silanes and / or silanols as well as condensation and co-condensation products based thereon (corresponding linear, branched, cyclic and possibly spatially cross-linked siloxanes) starting from compounds of the general formulas I, II or III and / or corresponding ancondensation products.

[0066] Preferably, the reaction, in particular hydrolysis as well as condensation or co-condensation, is carried out at a temperature < 100°C, preferably from 10 to 80°C, particularly preferably from 15 to 60°C, and especially from 20 to 50°C.

[0067] Optionally, an organic or inorganic acid can be used in the preparation of the mixture. Hydrochloric acid (HCl or aqueous hydrochloric acid), aqueous acetic acid, or aqueous formic acid can be advantageously used, the water added thereby being added to the amount of water required for the targeted hydrolysis of the alkoxysilanes according to the invention. However, the acid can also be added after the preparation of the mixture, preferably to a pH of 2 to 6, and particularly 3 to 5.

[0068] In particular, the mixture is prepared by distillation of the product mixture from the reaction; that is, the components that are otherwise readily volatile under ambient conditions, especially the hydrolysis alcohol and any added solvent or diluent, are preferably distilled off at least partially from the resulting product mixture under gentle heating and reduced pressure. If necessary, the amount of volatile components removed from the system can be replaced by the same volume of water and / or acid.

[0069] The mixture preferably contains organic or inorganic acid, with a suitably neutralization degree of 0 to 125%, preferably 0.1 to 120%, particularly preferably 70 to 115%, and most preferably 75 to 110%, based on the amine number. The determination of the amine number can generally be carried out according to DIN 32 625 (potentiographic titration with HCl).

[0070] Preferably, the acid used is an inorganic or organic acid, in particular hydrochloric acid, acetic acid or formic acid, wherein the aminoalkyl and oligo-silylated aminoalkyl functional silicon compounds in the present composition are, according to chemical understanding, at least partially present as a cationic amine mixture, i.e., that a composition used according to the invention preferably has a content of acid and / or a corresponding salt of acid and one of the present amino functional compounds.

[0071] The mixture can have a viscosity of 2 to 1000 mPa s, preferably 3 to 500 mPa s, particularly preferably 4 to 250 mPa s, the viscosity being determined, for example, according to DIN 53 015.

[0072] The proportion of component d) is 0.001 wt.% to 5 wt.% based on the total weight of the hot melt adhesive composition according to the invention. Preferably, the proportion is 0.001 wt.% to 2 wt.%. More preferably, the proportion is 1.2 wt.%.

[0073] In addition to the components listed above a) to d), the hot melt adhesive composition according to the invention may contain further components.

[0074] The hot melt adhesive composition according to the invention can contain at least one silicone resin, such as a phenyl silicone resin. Silicone resins are described, for example, in DE 10 2013 213 835 A1. Within the scope of the present invention, a silicone resin is considered an additional component, provided it is not already one of the components mentioned above.

[0075] Accordingly, possible silicone resins according to DE 10 2013 213 835 A1 contain units of the formula R 3'< c' (R 4'< O) d' R 5'< e' SiO (4-c'-d'-e') / 2 (II), wherein R 3'< may be the same or different and represents a hydrogen atom, a monovalent, SiC-bonded, optionally substituted aliphatic hydrocarbon residue, or a divalent, optionally substituted, aliphatic hydrocarbon residue bridging two units of formula (II); R 4'< may be the same or different and represents a hydrogen atom or a monovalent, optionally substituted hydrocarbon residue; R 5'< may be the same or different and represents a monovalent, SiC-bonded, optionally substituted aromatic hydrocarbon residue; c' is 0, 1, 2, or 3; d' is 0, 1, 2, or 3, preferably 0, 1, or 2, particularly preferably 0 or 1; and e' is 0, 1, or 2, preferably 0 or 1, provided that the sum of c' + d' + e' is less than or equal to 3, e' is different from 0 in at least one unit, and in at least 40% of the units of formula (II) the sum c' + e' is equal to 0 or 1.

[0076] Suitable silicone resins preferably consist of at least 90 wt.% units of formula (II), particularly preferably exclusively of units of formula (II).

[0077] Examples of R 3'< groups are alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, 1-n-butyl, 2-n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, and tert-pentyl groups; hexyl groups, such as n-hexyl; heptyl groups, such as n-heptyl; octyl groups, such as n-octyl, isooctyl, and 2,2,4-trimethylpentyl; nonyl groups, such as n-nonyl; decyl groups, such as n-decyl; dodecyl groups, such as n-dodecyl; and octadecyl groups, such as n-octadecyl. Cycloalkyl groups, such as cyclopentyl, cyclohexyl, cycloheptyl and methylcyclohexyl groups; alkenyl groups, such as vinyl, 1-propenyl and 2-propenyl groups; aryl groups, such as phenyl, naphthyl, anthryl and phenanthryl groups; alkaryl groups, such as o-, m-, p-tolyl groups; xylyl groups and ethylphenyl groups; and aralkyl groups, such as benzyl, o- and β-phenylethyl groups.

[0078] Examples of substituted residues R 3'< are haloalkyl residues, such as the 3,3,3-trifluoro-n-propyl residue, the 2, 2,2,2',2',2'-hexafluoroisopropyl residue and the heptafluoroisopropyl residue, and haloaryl residues, such as the o-, m- and p-chlorophenyl residue.

[0079] Preferably, the residue R 3'< is a monovalent hydrocarbon residue with 1 to 6 carbon atoms, optionally substituted with halogen atoms, and particularly preferably an alkyl residue with 1 or 2 carbon atoms, especially a methyl residue. However, the residue R 3'< can also be a divalent aliphatic residue linking two silyl groups of formula (II), such as alkylene residues with 1 to 10 carbon atoms, like methylene, ethylene, propylene, or butylene residues.

[0080] Preferably, however, residue R 3'< is a monovalent SiC-bonded aliphatic hydrocarbon residue with 1 to 18 carbon atoms, optionally substituted with halogen atoms, and particularly preferably an aliphatic hydrocarbon residue with 1 to 6 carbon atoms, especially the methyl residue.

[0081] Examples for residue R 4'< are hydrogen atoms or the examples given for residue R 3'<.

[0082] Preferably, the residue R 4'< is a hydrogen atom or optionally alkyl residues substituted with halogen atoms with 1 to 10 carbon atoms, particularly preferably alkyl residues with 1 to 4 carbon atoms, especially the methyl and ethyl residues.

[0083] Examples of residues R 5'< are the aromatic residues listed above for R 3'<.

[0084] Preferably, the residue R 5'< is a SiC-bonded aromatic hydrocarbon residue with 1 to 18 carbon atoms, optionally substituted with halogen atoms, such as ethylphenyl, toluyl, xylyl, chlorophenyl, naphtyl or styryl residues, particularly preferably the phenyl residue.

[0085] Silicone resins are preferably used in which at least 90% of all residues R 3'< represent methyl residues, at least 90% of all residues R 4'< represent methyl, ethyl, propyl or isopropyl residues and at least 90% of all residues R 5'< represent phenyl residues.

[0086] Preferably, silicone resins are used which have at least 40%, particularly preferably at least 60%, units of formula (II) in which c' is equal to 0, in each case based on the total number of units of formula (II).

[0087] Preferably, silicone resins are used which, based on the total number of units of formula (II), have at least 70%, particularly preferably at least 80%, units of formula (II) in which d' represents the value 0 or 1.

[0088] Preferably, silicone resins are used which, based on the total number of units of formula (II), at least 20%, and particularly preferably at least 40%, have units of formula (II) in which e' represents the value 1. Silicone resins may be used which exclusively have units of formula (II) in which e' is equal to 1, but particularly preferably at least 10%, particularly preferably at least 20%, at most 60%, and particularly preferably at most 80%, of the units of formula (II) have an e' of 0.

[0089] Preferably, silicone resins are used which, based on the total number of units of formula (II), have at least 50%, particularly preferably at least 70%, in particular at least 80%, units of formula (II) in which the sum c' + e' is equal to 1.

[0090] In a particularly preferred embodiment of the invention, silicone resins are used which, based on the total number of units of formula (II), comprise at least 20%, and particularly preferably at least 40%, units of formula (II) in which e' represents the value 1 and c' represents the value 0. Preferably, at most 40%, and particularly preferably at most 70%, of all units of formula (II) have a d' other than 0.

[0091] In a further particularly preferred embodiment of the invention, silicone resins are used which, based on the total number of units of formula (II), comprise at least 20%, particularly preferably at least 40%, units of formula (II) in which e' represents the value 1 and c' represents the value 0, and which also comprise at least 1%, preferably at least 10%, units of formula (II) in which c' represents 1 or 2, preferably 1, and e' represents 0.

[0092] Examples of silicone resins are organopolysiloxane resins, which consist essentially, preferably exclusively, of (Q) units of the formulas SiO₄ / 2, Si(OR₄'< )O₃ / 2, Si(OR₄'< )₂O₂ / 2 and Si(OR₄'< )₃O₁ / 2, (T) units of the formulas PhSiO₃ / 2, PhSi(OR₄'< )O₂ / 2, PhSi(OR₄'< )₂O₁ / 2, MeSiO₃ / 2, MeSi(OR₄'< )O₂ / 2 and MeSi(OR₄'< )₂O₁ / 2, and (D) units of the formulas Me₂SiO₂ / 2, Me₂Si(OR₄'< )O₁ / 2, Ph₂SiO₂ / 2 and Ph₂Si(OR₄'< )₂O₁ / 2 )O 1 / 2 , MePhSiO 2 / 2 and MePhSi(OR 4'< )O 1 / 2 as well as (M) units of the formula Me 3 SiO 1 / 2, wherein Me represents a methyl group, Ph represents a phenyl group and R 4'< represents a hydrogen atom or optionally halogen-substituted alkyl groups with 1 to 10 carbon atoms, particularly preferably around a hydrogen atom or alkyl groups with 1 to 4 carbon atoms, wherein the resin contains 0-2 mol (Q) units, 0-2 mol (D) units and 0-2 mol (M) units per mol (T) units.

[0093] Preferred examples of silicone resins are organopolysiloxane resins consisting essentially, preferably exclusively, of T-units of the formulas PhSiO 3 / 2 , PhSi(OR 4'< )O 2 / 2 and PhSi(OR 4'< ) 2 O 1 / 2 , T-units of the formulas MeSiO 3 / 2 , MeSi(OR 4'< )O 2 / 2 and MeSi(OR 4'< ) 2 O 1 / 2 , and D-units of the formulas Me 2 SiO 2 / 2 and Me 2 Si(OR 4'< )O 1 / 2 , wherein Me represents a methyl group, Ph a phenyl group, and R 4'< a hydrogen atom or optionally halogen-substituted alkyl groups with 1 to 10 carbon atoms, particularly preferably around a hydrogen atom or alkyl groups with 1 to 4 carbon atoms, with a molar ratio of (T)- to (D) units from 0.5 to 2.0.

[0094] Among these examples, silicone resins are particularly preferred whose units of formula (II) are formed to at least 50%, preferably at least 70%, in particular at least 85% from T-units of formulas PhSiO 3 / 2 , PhSi(OR 4'< )O 2 / 2 , PhSi(OR 4'< ) 2 O 1 / 2 , Me SiO 3 / 2 , MeSi(OR 4'< )O 2 / 2 and MeSi(OR 4'< ) 2 O 1 / 2, wherein these silicone resins contain at least 30%, preferably at least 40%, in particular at least 50% T-units of formulas PhSiO 3 / 2 , PhSi(OR 4'< )O 2 / 2 and PhSi(OR 4'< ) 2 O 1 / 2 and at least 10%, preferably at least 15%, in particular at least 20% T-units of MeSiO 3 / 2 , MeSi(OR 4'< )O 2 / 2 and MeSi(OR 4'< ) 2 O 1 / 2 are included.

[0095] Preferably, the silicone resins have a mean molar mass (number-average) Mn of at least 500 g / mol and particularly preferably of at least 600 g / mol. The mean molar mass Mn is preferably at most 400,000 g / mol, particularly preferably at most 100,000 g / mol, and especially at most 50,000 g / mol.

[0096] Such silicone resins can be both solid and liquid at 23°C and 1000 hPa, with silicone resins preferably being liquid.

[0097] The silicone resins are commercially available products (for example, Silres® IC 368 from Wacker Chemie (DE)) or they can be produced using methods common in silicon chemistry.

[0098] Furthermore, the reactive hot melt adhesive composition according to the present invention can additionally contain at least one tackifier polymer. The proportion is advantageously between 10 wt.% and 40 wt.% based on the total weight of the composition.

[0099] Furthermore, the reactive hot melt adhesive composition according to the present invention can additionally contain at least one filler. Advantageously, its proportion is 10 wt.% to 40 wt.% based on the total weight of the composition. Exemplary fillers are calcium carbonate, for example chalk, or corundum, such as aluminum oxide. The use of filler can prevent or reduce stringing during processing of the adhesive composition.

[0100] The reactive hot melt adhesive compositions according to the invention allow for high filler levels, which can be advantageous in various applications. Examples include applications requiring good thermal conductivity or specific fire behavior requirements.

[0101] Another aspect of the present invention is a method for producing a reactive hot melt adhesive composition according to the present invention, comprising steps (a) to (d).

[0102] In a first step (a) at least one acrylate resin-based polymer is added to at least one chemical compound that is liquid at least at 100 °C and in which the at least one acrylate resin-based polymer dissolves at least at 150 °C.

[0103] Likewise, at least one acrylic resin-based polymer can be added to a mixture containing at least one chemical compound.

[0104] The addition takes place at a temperature in the range of 130 °C to 170 °C, preferably in the range of 140 °C to 160 °C, and particularly at 150 °C.

[0105] Furthermore, a sticky polymer can be added in step (a).

[0106] In a next step (b) the mixture is cooled to a temperature in the range of 80°C to 120°C.

[0107] The next step (c) is the addition of at least one alpha-silane-terminated organic polymer to the cooled mixture.

[0108] Finally, in step (d) at least one oligomeric silane containing one or more amino groups is added, resulting in a reactive hot melt adhesive composition according to the present invention.

[0109] In step (c) at least one filler may be added. Preferably, steps (c) and (d) are carried out sequentially in such a way that degassing can occur between the steps.

[0110] The reactive hot melt adhesive composition according to the invention is roller-stable and therefore suitable for application via rollers. Accordingly, the reactive hot melt adhesive composition according to the invention is particularly suitable for a surface lamination process in which the reactive hot melt adhesive composition according to the present invention is applied to a substrate using an application roller.

[0111] Surprisingly, it has been shown that the coating can be cleaned using a roller coating machine even after the roller stability period has been exceeded, i.e., when the binder exhibits noticeable stringiness during processing, which determines the coating appearance.

[0112] Accordingly, a further object of the present invention is the use of a reactive hot melt adhesive composition according to the invention for roller application.

[0113] Advantageous applications of the reactive hot-melt adhesive compositions according to the invention result from their good adhesion and initial tack. Even when no roller application is used, for example, in window profile cladding, the advantageous properties listed below are evident. Further applications include those where improved thermal conductivity can be achieved. Applications that are associated with improved fire behavior should also be mentioned.

[0114] The following advantages are particularly evident: Isocyanate-free, good adhesion spectrum, especially on metals, glass and other materials. No foaming due to CO2 formation.

Claims

1. A reactive hotmelt adhesive composition comprising, based on the total weight of the composition, a) 3 wt% to 49 wt% of at least one alpha-silane-terminated organic polymer; b) 1 wt% to less than 20 wt%, preferably 1 wt% to 10 wt%, of at least one acrylate resin-based polymer; c) 1 wt% to 20 wt%, preferably 1 wt% to 10 wt%, of at least one chemical compound which is liquid at least at 100°C and in which at least at 150°C the at least one acrylate resin-based polymer dissolves; d) 0.001 wt% to 5 wt%, preferably 0.001 wt% to 2 wt%, of at least one oligomeric silane comprising one or more amino groups.

2. The reactive hotmelt adhesive composition as claimed in claim 1, characterized in that the at least one alpha-silane-terminated organic polymer comprises a multiplicity of end groups of the formula *-X-C(=O)-N(R)-C(R1R2)-Si(R3)a(OR4)3-a, where X is O or N(R); each R independently of any other is hydrogen or a hydrocarbon radical having 1 to 20 carbon atoms; R1 and R2 independently of one another are hydrogen or a hydrocarbon radical having 1 to 20 carbon atoms; R3 and R4 independently of one another are a hydrocarbon radical having 1 to 20 carbon atoms; a is 1 or 2; and "*" marks the bond for attachment to the polymer.

3. The reactive hotmelt adhesive composition as claimed in claim 1 or 2, characterized in that the organic polymer is a polyoxyalkylene, a hydrocarbon polymer, a polyurethane, a polyester, a polyamide, a polyacrylate, a polymethacrylate or a polycarbonate.

4. The reactive hotmelt adhesive composition as claimed in any of claims 1 to 3, characterized in that the acrylate resin-based polymer is a homoacrylate, a homomethacrylate, a copolymer of at least two different acrylates, a copolymer of at least two different methacrylates or a copolymer of at least one acrylate and at least one methacrylate.

5. The reactive hotmelt adhesive composition as claimed in any of claims 1 to 4, characterized in that the at least one chemical compound which is liquid at least at 100°C and in which at least at 150°C the at least one acrylate resin-based polymer dissolves, is a plasticizer.

6. The reactive hotmelt adhesive composition as claimed in any of claims 1 to 4, characterized in that the at least one chemical compound which is liquid at least at 100°C and in which at least at 150°C the at least one acrylate resin-based polymer dissolves is a polyalkylene glycol.

7. The reactive hotmelt adhesive composition as claimed in any of claims 1 to 4, characterized in that the at least one chemical compound which is liquid at least at 100°C and in which at least at 150°C the at least one acrylate resin-based polymer dissolves is an alkoxysilane.

8. The reactive hotmelt adhesive composition as claimed in any of claims 1 to 7, characterized in that the at least one oligomeric silane comprising one or more amino groups is a mixture of amino group-containing alkoxy- / hydroxy-silanes and / or silanols and condensation products and co-condensation products based thereon and preferably has a molecular weight of more than 500 g / mol.

9. The reactive hotmelt adhesive composition as claimed in any of claims 1 to 8, characterized in that the composition further comprises 10 wt% to 40 wt% of at least one tackifying polymer (tackifier), based on the total weight of the composition.

10. The reactive hotmelt adhesive composition as claimed in any of claims 1 to 9, characterized in that the composition further comprises 10 wt% to 40 wt% of at least one filler, based on the total weight of the composition.

11. A process for producing a reactive hotmelt adhesive composition as claimed in any of claims 1 to 10, comprising the steps of (a) adding at least one acrylate resin-based polymer to at least one chemical compound which is liquid at least at 100°C and in which at least at 150°C the at least one acrylate resin-based polymer dissolves, or adding it to a mixture which comprises the at least one chemical compound, at a temperature in the range of 130°C to 170°C; (b) cooling the mixture to a temperature in the range from 80°C to 120°C; (c) adding at least one alpha-silane-terminated organic polymer to the cooled mixture; (d) adding at least one oligomeric silane comprising one or more amino groups, to give a reactive hotmelt adhesive composition as claimed in any of claims 1 to 10.

12. The process as claimed in claim 11, characterized in that in step (a) additionally a tackifying polymer is added.

13. The process as claimed in claim 11 or 12, characterized in that in step (c) further at least one filler is added.

14. The process as claimed in any of claims 11 to 13, characterized in that the steps (c) and (d) take place successively and degassing is carried out between the steps.

15. A process for surface lamination, comprising the step of - applying a reactive hotmelt adhesive composition as claimed in any of claims 1 to 10 to a substrate by means of an applicator roll.