Reactive hot-melt adhesive compositions based on alpha-silane-terminated organic polymers

Abstract

The present invention relates to a reactive hot-melt adhesive composition, containing, in relation to the total weight of the composition, a) 3 wt.% to 79.999 wt.% of at least one alpha-silane-terminated organic polymer; b) 20 wt.% to 96.999 wt.% of at least one silane-terminated polyurethane which is not an alpha-silane-terminated polyurethane; c) 0 wt.% to 70 wt.% of at least one filler; d) 0.001 wt.% to 3 wt.% of at least one silane which has a primary or secondary amino group or a blocked amino group which hydrolyses to form the primary or secondary amino group; wherein the at least one silane-terminated polyurethane b), which is not an alpha-silane-terminated polyurethane, can be obtained by a reaction in which at least one polyol (1) reacts with at least one polyisocyanate (2), optionally in the presence of at least one chain terminator (3), such that a polyurethane prepolymer is formed which, in a further reaction, is reacted with at least one secondary aminosilane (4), which is not an alpha-aminosilane, such that the content of free isocyanate is less than 0.1 wt.% in relation to the total weight of the silane-terminated polyurethane b), and wherein the following proportions result in relation to the sum of the reactants (1), (2), (3) and (4): 1) 40 wt.% to 85 wt.% of the at least one polyol; 2) 10 wt.% to 50 wt.% of the at least one polyisocyanate; 3) 0 wt.% to 25 wt.% of the at least one chain terminator; 4) 1 wt.% to 15 wt.% of the at least one secondary aminosilane, which is not an alpha-aminosilane. The invention also relates to methods for the preparation thereof and to a method for laminating surfaces using the composition.

Description

[0001] Reactive hot melt adhesive compositions based on alpha-silane-termated organic polymers

[0002] The present invention relates to reactive hot melt adhesive compositions and further to methods for their production as well as a method for surface lamination using the composition.

[0003] 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, Vincent Network; 1st edition, December 2004).

[0004] 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.

[0005] 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).

[0006] 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.

[0007] 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 advantageous 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.

[0008] In the course of this development, two approaches were initially pursued for the production of silane-based formulations. Besides the silanization of existing reactive PUR 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.

[0009] For example, WO 2007 / 074143 A1 describes moisture-curing hot melt adhesive compositions using silane-functionalized polyurethane prepolymers.

[0010] WO 2013 / 026654 A1 describes crosslinkable compounds based on organyloxysilane-terminated polymers. As in DE 10 2013213 835 A1, mixtures of alpha-silanes, such as Geniosil® STP-E10, and silicone resins are described.

[0011] WO 2011 / 087741 A2 describes adhesives for binding books and related objects and the production of such adhesives using silane-modified liquid polymers. In particular, the adhesives are intended to have a reduced or no monomeric diisocyanate content. Initially, the results were unsatisfactory in both cases. The formulations obtained had insufficient initial adhesion, were not roller-resistant, or cured too slowly.

[0012] WO 2021 / 214290 A1 and WO 2023 / 066902 A1 describe adhesive formulations with binders based on silane-terminated polymers with dimethoxy(methyl)silylmethylcarbamate end groups (so-called alpha-silanes). To achieve good initial adhesion, the dissolution of an acrylate resin in a liquid chemical compound is an essential component of these formulations according to the invention. The initial adhesion can optionally be further improved by adding non-reactive resins. However, dissolving an acrylate resin in a liquid chemical compound represents an additional process step, which is associated with higher production costs. The addition of a chemical compound that is liquid at room temperature can, in principle, impair the hot melt adhesive properties of these formulations.

[0013] Therefore, there is a need for further improved reactive hot melt adhesive compositions that can at least mitigate or prevent the aforementioned disadvantages.

[0014] One object of the present invention is therefore to provide such compositions and methods for their production.

[0015] The problem was solved by a reactive hot melt adhesive composition, based on the total weight of the composition, containing a) 3 wt.% to 79.999 wt.% of at least one alpha-silane-terminated organic polymer; b) 20 wt.% to 96.999 wt.% of at least one silane-terminated polyurethane that is not an alpha-silane-terminated polyurethane; c) 0 wt.% to 70 wt.% of at least one filler; d) 0.001 wt.% to 3 wt.% of a filler.-% of at least one silane having a primary or secondary amino group or a blocked amino group hydrolyzed to the primary or secondary amino group; wherein the at least one silane-terminated polyurethane b), which is not an alpha-silane-terminated polyurethane, is obtained by a reaction in which at least one polyol (1) reacts with at least one polyisocyanate (2), optionally in the presence of at least one chain terminator (3), to form a polyurethane prepolymer which is further reacted with at least one secondary aminosilane (4), which is not an alpha-aminosilane, such that the free isocyanate content is less than 0.1 wt% based on the total weight of the silane-terminated polyurethane b), and wherein the following proportions are obtained based on the sum of the reactants (1), (2), (3) and (4):.

[0016] 1) 40% to 85% by weight of at least one polyol;

[0017] 2) 10 wt.% to 50 wt.% of the at least one polyisocyanate;

[0018] 3) 0 wt.% to 25 wt.% of the at least one chain breaker;

[0019] 4) 1 wt.% to 15 wt.% of at least one secondary aminosilane that is not an alpha-aminosilane.

[0020] The problem was further solved by a method for producing a reactive hot melt adhesive composition according to the invention, comprising steps

[0021] (a) Producing at least one silane-terminated polyurethane (b), which is not an alpha-silane-terminated polyurethane, by a reaction in which at least one polyol (1) reacts with at least one polyisocyanate (2), optionally in the presence of at least one chain terminator (3), to form a polyurethane prepolymer, which is further reacted with at least one secondary aminosilane (4), which is not an alpha-aminosilane, such that the content of free isocyanate is less than 0.1 wt% based on the total weight of the silane-terminated polyurethane (b), wherein the following proportions are obtained in relation to the sum of the reactants (1), (2), (3) and (4):

[0022] 1) 40% to 85% by weight of at least one polyol;

[0023] 2) 10 wt.% to 50 wt.% of the at least one polyisocyanate;

[0024] 3) 0 wt.% to 25 wt.% of the at least one chain breaker;

[0025] 4) 1% by weight to 15% by weight of at least one secondary aminosilane that is not an alpha-aminosilane;

[0026] (b) Mixing the at least one silane-terminated polyurethane (b) from step (a) with the at least one alpha-silane-terminated organic polymer (a);

[0027] (c) Optionally adding the at least one filler c); and (d) adding the at least one silane d), which has a primary or secondary amino group or a blocked amino group which hydrolyzes to the primary or secondary amino group.

[0028] The problem was also solved by a surface lamination method comprising the step of applying a reactive hot melt adhesive composition according to the invention to a substrate using an application roller.

[0029] Surprisingly, it has been shown that adhesives with improved properties can be formulated using astonishingly simple silane-terminated polyurethanes containing the components described above. For example, the reactive hot melt adhesive compositions according to the invention are characterized by excellent roller stability, high initial tack, and good curing time. Furthermore, the reactive hot melt adhesive compositions according to the invention can be low-viscosity at temperatures of 90–120 °C. Reliable application via rollers is possible.

[0030] It has also been shown that the use of additional resins to improve initial adhesion is not necessary. In particular, the use of non-polar, non-reactive resins can be avoided, as these have the inherent disadvantage that the formulations produced with them exhibit poor adhesion to polar substrates. Due to the increasing hydrophobization, the formulation cures less effectively in the presence of moisture, and the non-reactive components generally weaken or even eliminate the reactive adhesive's properties. The reactive hot melt adhesive compositions according to the invention are therefore particularly suitable for polar substrate surfaces.

[0031] Furthermore, the reactive hot melt adhesive compositions according to the invention exhibit high crosslinking densities, which can justify good plasticizer resistance.

[0032] An object of the present invention is a reactive hot melt adhesive composition, based on the total weight of the composition comprising: a) 3 wt.% to 79.999 wt.% of at least one alpha-silane-terminated organic polymer; b) 20 wt.% to 96.999 wt.% of at least one silane-terminated polyurethane, which is not an alpha-silane-terminated polyurethane; c) 0 wt.% to 70 wt.% of at least one filler; d) 0.001 wt.% to 3 wt.% of a filler.-% of at least one silane having a primary or secondary amino group or a blocked amino group hydrolyzed to the primary or secondary amino group; wherein the at least one silane-terminated polyurethane b), which is not an alpha-silane-terminated polyurethane, is obtained by a reaction in which at least one polyol (1) reacts with at least one polyisocyanate (2), optionally in the presence of at least one chain terminator (3), to form a polyurethane prepolymer which is further reacted with at least one secondary aminosilane (4), which is not an alpha-aminosilane, such that the free isocyanate content is less than 0.1 wt% based on the total weight of the silane-terminated polyurethane b), and wherein the following proportions are obtained based on the sum of the reactants (1), (2), (3) and (4):.

[0033] 1) 40% to 85% by weight of at least one polyol;

[0034] 2) 10 wt.% to 50 wt.% of the at least one polyisocyanate;

[0035] 3) 0 wt.% to 25 wt.% of the at least one chain breaker;

[0036] 4) 1 wt.% to 15 wt.% of at least one secondary aminosilane, which is not an alpha-aminosilane. Reactive hot melt adhesive composition, based on the total weight of the composition containing

[0037] The reactive hot melt adhesive composition according to the invention can be reliably processed using application rollers. The processing temperature is preferably between 90 and 120 °C. At processing temperature, the reactive hot melt adhesive composition according to the invention preferably has a viscosity in the range of 1 Pa s to 40 Pa s and, after cooling to room temperature, exhibits a high initial tack characteristic of hot melt adhesives. The viscosity can be determined using standard methods that also underlie commercially available viscometers. For example, the viscosity can be determined according to DIN 53019-1:2008-09, DIN 53019-2:2001-02 and DIN 53019-3:2008-09 as well as DIN EN ISO 2555:2018-09.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 via a condensation reaction, forming siloxane groups.

[0038] Preferably, the reactive hot melt adhesive composition according to the invention is isocyanate-free.

[0039] The reactive hot melt adhesive composition according to the invention contains components a), b), and d) and may also include further components. In one embodiment, the reactive hot melt adhesive composition according to the invention may not contain component c) (0 wt.% of the at least one filler). In an alternative embodiment, the reactive hot melt adhesive composition according to the invention contains component c), for example, in a proportion of at least 0.1 wt.% based on the total weight of the composition. 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 which, in addition to components a) to d), further comprises one or more components, such as two, three, four, five, six, seven, eight, nine, or ten components.

[0040] The present invention therefore relates to a reactive hot melt adhesive composition. The term “hot melt adhesive” 1This describes an adhesive that is solid at room temperature or has a high shear modulus and is liquid at elevated temperatures, usually between 90 °C and 120 °C. Hot melt adhesives are applied in liquid form and then solidify, so that they are solid again 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. Component a) of the reactive hot melt adhesive composition according to the invention contains at least one alpha-silane-terminated organic polymer.

[0041] In alpha-silanes, a two-stage condensation reaction of alkoxysilanes is known to occur 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 additional co-catalysts such as organotin compounds or diazabicycloundecene. Surprisingly, this invention has demonstrated that formulations containing an alpha-silane are roller-stable for 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 additional co-catalysts.

[0042] 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.

[0043] 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.

[0044] Alpha-silanes are characterized by the so-called alpha effect, which is described in detail in the literature, for example in Schindler, W. Silane-terminated polyethers with alpha effect. Adhaes Kleb Dicht 48, 28-32 (2004). In this effect, for example, a nitrogen atom in the alpha position to a silicon atom can make its alkoxy group(s) more reactive. Alpha-silanes are therefore more reactive towards water, among other things, which causes accelerated hydrolysis without the need for, for example, tin-containing catalysts. The hydrolysis of the silanes can occur 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.

[0045] Preferably, the at least one alpha-silane-terminated organic polymer is a polymer comprising 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 has

[0046] X for O or N(R 5 ) stands;

[0047] R, R 1 , R 2 and R 5 independently of each other they stand for hydrogen or a hydrocarbon residue with 1 to 20 carbon atoms;

[0048] R 3 and R 4 independently of each other, they represent a hydrocarbon residue with 1 to 20 carbon atoms; a represents 0, 1 or 2 and

[0049] “*” indicates the bond for attachment to the polymer.

[0050] R and R are more preferred 5for hydrogen or an alkyl group comprising 1 to 6 carbon atoms, wherein the alkyl group may be straight-chain, branched, or cyclic. More preferably, R and R are 5 around H, methyl or ethyl, more preferably around hydrogen or methyl.

[0051] Hydrogen is particularly preferred in R when X = O.

[0052] R is particularly preferably an alkyl group with 1 to 6 carbon atoms and R 5 H is when X = N(R 5 ) is.

[0053] R are more preferred 1 and R 2 the same. Furthermore, R are more preferred. 1 and R 2 Hydrogen or an alkyl group comprising 1 to 4 carbon atoms, wherein the alkyl group may be straight-chain or branched. More preferably, R 1 and R 2 around H, methyl or ethyl, more preferably around hydrogen or methyl.

[0054] R are particularly preferred1 and R 2 Hydrogen.

[0055] R are more preferred 3 and R 4 the same. Furthermore, R are more preferred. 3 and R 4 An alkyl group comprising 1 to 4 carbon atoms, wherein the alkyl group may be straight-chain or branched. More preferably, R 3 and R 4 for methyl or ethyl. In particular, R 3 and R 4 Methyl.

[0056] Preferably a = 0 or 1, more preferably a = 1.

[0057] 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-CH2-Si(CH3)(OCH3)2.

[0058] 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.

[0059] 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.

[0060] Component a) comprises a proportion of 3 wt.% to 79.999 wt.% based on the total weight of the composition. Preferably, the proportion is 3 to 20 wt.%, more preferably 5 to 10 wt.%.

[0061] The reactive hot melt adhesive composition according to the invention further comprises a component d). This component is at least one silane having a primary or secondary amino group or a blocked amino group that hydrolyzes to the primary or secondary amino group. Thus, component d) can have 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 component d) insofar as it cannot be considered one of components a) to c). In particular, the silane of component d) does not have any alpha-silane groups and is of a low molecular weight or oligomeric nature and is therefore not a polymer. The proportion of component d) is 0.001 wt.% to 3 wt.% based on the total weight of the hot melt adhesive composition according to the invention. Preferably, the proportion is 0.3 wt.%.-% to 1.2 wt.%. Preferably, the proportion is 0.6 wt.%.

[0062] In one embodiment, the silane of component d) is at least a low molecular weight silane having a primary or secondary, preferably a primary, amino group or a blocked amino group which hydrolyzes to the primary or secondary amino group.

[0063] The at least one low-molecular-weight silane of component d) has a primary amino group -NH₂. This amino group can be part of a functional group, such as an amide group -C(=O)NH₂, or a primary amine in the narrower sense. Advantageously, it is an amine. Low-molecular-weight silanes with a secondary amino group can also be used. Blocked aminosilanes can also be used. In this case, the blocked amino group hydrolyzes to the primary or secondary amino group, preferably to the primary amino group. ((Triethoxysilyl)propyl)methylisobutylimine is an example. Here, too, the amino group can be part of a functional group, or it can be an amino group, which is preferred.Of course, several primary amino groups can be present, in particular several primary amino groups, several secondary amino groups, and at least one primary and at least one secondary amino group. The blocked form of the primary or secondary amino group can, of course, be used instead. However, a primary or secondary amino group is preferred, and a primary amino group is more preferred.

[0064] Advantageous low molecular weight silanes have a molecular weight in the range of 100 g / mol to 500 g / mol.

[0065] Preferred low molecular weight silanes are described in DE 102012 200790 A1. Accordingly, preferred low molecular weight silanes are those containing units of the formula

[0066] DSi(OR 7 ')g'R 8 '(3-g) (IX), wherein

[0067] R 7' can be the same or different and means hydrogen atom or, if applicable, substituted hydrocarbon residues, D can be the same or different and means a monovalent, SiC-bonded residue with basic nitrogen of a primary, or secondary or blocked amino group, R 8 ' can be the same or different and means a monovalent, optionally substituted SiC-bound organic residue free of basic nitrogen, g' 1 , 2 or 3, preferably 2 or 3.

[0068] Examples of possibly substituted hydrocarbon residues R 7 ' are those for the rest R 3 'Examples shown below.

[0069] Regarding the remaining R 7' preferably it is a hydrogen atom and optionally substituted with halogen atoms hydrocarbon residues with 1 to 18 carbon atoms, particularly preferably a hydrogen atom and hydrocarbon residues with 1 to 10 carbon atoms, in particular a methyl and ethyl residue.

[0070] Examples of remainder R 8 ' are the ones for R 3 'Examples shown below.

[0071] With the remainder R 8 'These are preferably hydrocarbon residues with 1 to 18 carbon atoms, optionally substituted with halogen atoms, particularly preferably hydrocarbon residues with 1 to 5 carbon atoms, especially the methyl residue.

[0072] Examples of residues D are residues of the formulas H2N(CH2)3-, H2N(CH2)2NH(CH2)3-, H2N(CH2)2NH(CH2)2NH(CH2)3-, H3CNH(CH2)3-, C2H5NH(CH2)3-, C3H7NH(CH2)3-,

[0073] C4H9NH(CH2)3-, C5HHNH(CH2)3-, C6Hi3NH(CH2)3-, C7HI5NH(CH2)3-, H2N(CH2)4-, H2N-CH2- CH(CH3)-CH2-, H2N(CH2)5-, cyclo-C5H9NH(CH2)3-, cyclo-C6HiiNH(CH2)3-, Phenyl-NH(CH2)3-, (CH3)2N(CH2)3-, (C2H5)2N(CH2)3-, (C3H7)2NH(CH2)3-, (C4H9)2NH(CH2)3-, (C5RH)2NH(CH2)3-, (C6Hi3)2NH(CH2)3- (C7Hi5)2NH(CH2)3-, H2N(CH2)-, H2N(CH2)2NH(CH2)-,

[0074] H2N(CH2)2NH(CH2)2NH(CH2)-, H3CNH(CH2)-, C2H5NH(CH2)-, C3H7NH(CH2)-, C4H9NH(CH2)-, C5HHNH(CH2)-, C6HI3NH(CH2)-, C7HI5NH(CH2)-, cyclo-C5H9NH(CH2)-, cyclo-C6HiiNH(CH2)-, Phenyl-NH(CH2)-, (CH3)2N(CH2)-, (C2H5)2N(CH2)-, (C3H7)2NH(CH2)-, (C4H9)2NH(CH2)-, (C5HII)2NH(CH2)-, (C6Hi3)2NH(CH2)- (C7Hi5)2NH(CH2)-, (CH3O)3Si(CH2)3NH(CH2)3-,

[0075] (C2H5O)3Si(CH2)3NH(CH2)3-, (CH3O)2(CH3)Si(CH2)3NH(CH2)3-

[0076] (C2HsO)2(CH3)Si(CH2)3NH(CH2)3- and reaction products of the above-mentioned primary amino groups with compounds containing reactive double bonds or epoxide groups towards primary amino groups (blocked amino groups). Examples of the silanes of formula (IX) are H2N(CH2)3-Si(OCH3)3, H2N(CH2)3-Si(OC2H5)3, H2N(CH2)3-Si(OCH3)2CH3, H2N(CH2)3-Si(OC2H5)2CH3, H2N(CH2)2NH(CH2)3-Si(OCH3)3,

[0077] H2N(CH2)2NH(CH2)3-Si(OC2H5)3, H2N(CH2)2NH(CH2)3-Si(OCH3)2CH3, H2N(CH2)2NH(CH2)3- Si(OC2H5)2CH3, H2N(CH2)2NH(CH2)3-Si(OH)3, H2N(CH2)2NH(CH2)3-Si(OH)2CH3,

[0078] H2N(CH2)2NH(CH2)2NH(CH2)3Si-(OCH3)3, H2N(CH2)2NH(CH2)2NH(CH2)3-Si(OC2H5)3, cyclo- C6HiiNH(CH2)3Si-(OCH3)3, cyclo-C6HiiNH(CH2)3-Si(OC2H5)3, cyclo-C6HiiNH(CH2)3-Si(OCH3)2CH3, cyclo-C6HnNH(CH2)3-Si(OC2H5)2CH3, cyclo-C6HnNH(CH2)3-Si(OC2H5)2CH3, cyclo-C6HnNH(CH2)3-Si(OH)3, cyclo- C6HiiNH(CH2)3-Si(OH)2CH3, Phenyl-NH(CH2)3-Si(OCH3)3, Phenyl-NH(CH2)3-Si(OC2H5)3, Phenyl-NH(CH2)3-Si(OCH3)2CH3, Phenyl-NH(CH2)3-Si(OC2H5)2CH3, Phenyl-NH(CH2)3-Si(OH)3, Phenyl-NH(CH2)3-Si(OH)2CH3, HN((CH2)3-Si(OCH3)3)2, HN((CH2)3-Si(OC2H5)3)2HN((CH2)3- Si(OCH3)2CH3)2, HN((CH2)3-Si(OC2H5)2CH3)2, cyclo-C6HnNH(CH2)-Si(OCH3)3, cyclo-

[0079] C6HiiNH(CH2)-Si(OC2H5)3, cyclo-C6HnNH(CH2)-Si(OCH3)2CH3, cyclo-C6HnNH(CH2)- Si(OC2H5)2CH3, cyclo-C6HiiNH(CH2)-Si(OH)3, cyclo-C6HiiNH(CH2)-Si(OH)2CH3, Phenyl- NH(CH2)-Si(OCH3)3, Phenyl-NH(CH2)-Si(OC2H5)3, Phenyl-NH(CH2)-Si(OCH3)2CH3, Phenyl-NH(CH2)-Si(OC2H5)2CH3, Phenyl-NH(CH2)-Si(OH)3und Phenyl-NH(CH2)-Si(OH)2CH3sowie deren Teilhydrolysate, where H2N(CH2)2NH(CH2)3-Si(OCH3)3, H2N(CH2)2NH(CH2)3-

[0080] Si(OC2H5)3, H2N(CH2)2NH(CH2)3-Si(OCH3)2CH3, cyclo-C6HnNH(CH2)3-Si(OCH3)3, cyclo-C6HnNH(CH2)3-Si(OC2Hs)3 and cyclo-C6HnNH(CH2)3-Si(OCH3)2CH3 and their respective partial hydrolysates preferably and H2N(CH2)2NH(CH2)3-Si(OCH3)3, H2N(CH2)2NH(CH2)3-

[0081] Si(OCH3)2CH3, cyclo-C6HnNH(CH2)3-Si(OCH3)3, cyclo-C6HiiNH(CH2)3-Si(OCH3)2CH3 and their respective partial hydrolysates are particularly preferred.

[0082] Particularly preferred examples include N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane, 3-Aminopropyltrimethoxysilane, 3-(2-Aminoethylamino)propyltriethoxysilane, N-(2-Aminoethyl)-3-aminopropylmethyldimethoxysilane, or 3-ureidopropyltrimethoxysilane. 3-Aminopropyltrimethoxysilane is especially preferred.

[0083] In a further embodiment, the silane of component d) is an oligomeric silane containing one or more amino groups, preferably with a molecular weight of more than 500 g / mol and preferably a mixture of amino group-containing alkoxy / hydroxy silanes and / or silanols as well as condensation and cocondensation products based thereon.

[0084] 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.

[0085] As already explained above, the oligomeric silane containing at least one or more amino groups can be a mixture that can be obtained by

[0086] (A) at least one aminoalkylalkoxysilane of general formula I

[0087] NR'2[(CH2)2NR'] 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 represents a bivalent alkylene group from the series -CH2-, -(CH2)2-, -(CH2)3- or -[CH2CH(CH3)CH2]-, x is equal to 0, 1 or 2 and n is equal to 0 or 1, or

[0088] (B) at least one bis-silylated alkylamine of general formula II (RO)3-m(R")mSi-Y-[NR'(CH2)2] y NR'[(CH2)2NR']zY-Si(R")n(OR)3- n(II), wherein groups R, R' and R" are the same or different and each represents a hydrogen atom or a linear or branched alkyl group with 1 to 8 carbon atoms, groups Y are the same or different and Y represents a bivalent alkylene group from the series -CH2-, -(CH2)2-, -(CH2)3- or -[CH2CH(CH3)CH2]-, y and z are independently equal to 0, 1 or 2 and m and n are independently equal to 0 or 1, or

[0089] (C) at least one tris-silylated alkylamine of general formula III

[0090] 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 C atoms, Y independently represents a bivalent alkylene group from the series -CH2-, -(CH2)2-, -(CH2)3- or -[CH2CH(CH3)CH2]- and n independently is equal to 0 or 1, or

[0091] (D) at least two of the aforementioned silylated alkylamines of general formulas 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. Mono-silylated amines are understood to be those of formula I. Oligo-silylated amines are understood to be 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.

[0092] In the preparation of the mixture, aminoalkylalkoxysilanes of general formula I are preferably used.

[0093] H2N(CH2)3Si(OCH3)3 (AMMO),

[0094] H2N(CH2)3Si(OC2H5)3 (AMEO),

[0095] H2N(CH2)2NH(CH2)3Si(OCH3)3 (DAMO),

[0096] H2N(CH2)2NH(CH2)2NH(CH2)3Si(OCH3)3 (TRIAMO), and possibly corresponding cyclic compounds.

[0097] Compounds according to formula II are preferred to be (H3CO)3Si(CH2)3NH(CH2)3Si(OCH3)3 (Bis-AMMO),

[0098] (H5C2O)3Si(CH2)3NH(CH2)3Si(OC2H5)3 (Bis-AMEO),

[0099] (H3CO)3Si(CH2)3NH(CH2)2NH(CH2)2NH(CH2)3Si(OCH3)3 (Bis-DAMO),

[0100] (H3CO)3Si(CH2)3NH(CH2)2NH(CH2)2NH(CH2)2NH(CH2)2NH(CH2)3Si(OCH3)3 (Bis-TRIAMO), and as compounds according to Formula III

[0101] N[CH2)3Si(OCH3)3]3 (Tris-AMMO),

[0102] N[CH2)3Si(OC2H5)3]3 (Tris-AMEO).

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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, especially from 20 to 50°C.

[0107] 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.

[0108] In particular, the mixture is prepared by distillation of the product mixture from the reaction; that is, the components that are otherwise highly 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. Thus, the mixture can preferably have an organic or inorganic acid content, 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 be carried out according to DIN 16945:1989-03.

[0109] 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.

[0110] 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, wherein the viscosity can be determined, for example, according to DIN 530195 (parts 1 to 3) and DIN EN ISO 2555.

[0111] The reactive hot melt adhesive composition according to the invention can contain one or more fillers c) and optionally one or more further components.

[0112] Accordingly, the composition may contain one filler or two, three, or more different fillers. If component c) is present, its proportion, based on the total weight of the composition, is up to 70 wt.%, preferably up to 35 wt.%. Fillers are known to those skilled in the art. An example of a filler is calcite. Other examples include calcium carbonate, such as chalk, or corundum, such as aluminum oxide. The use of fillers can prevent or reduce stringing during processing of the adhesive composition.

[0113] Furthermore, one or more, for example one, two, or three, additional components may be included. Preferably, however, the reactive hot melt adhesive composition according to the invention does not contain acrylic resins such as those used in WO 2021 / 214290 A1 and WO 2023 / 066902 A1. Accordingly, the reactive hot melt adhesive composition according to the invention is preferably free of one or more acrylate resin-based polymers that are not silane-terminated organic polymers. The hot melt adhesive composition according to the invention may 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. A silicone resin is considered an additional component within the scope of the present invention, provided it is not already one of the components mentioned above.

[0114] Accordingly, possible silicone resins according to DE 10 2013 213 835 A1 contain units of the formula

[0115] R 3 c'(R 4 'O)d'R 5 e SiO(4-c'-d'- e ') / 2 (II), wherein

[0116] R 3 'may be the same or different and means hydrogen atom, a monovalent, SiC-bound, optionally substituted aliphatic hydrocarbon residue or a divalent, optionally substituted, aliphatic hydrocarbon residue bridging two units of formula (II),

[0117] R 4 ' can be the same or different and means a hydrogen atom or a monovalent, possibly substituted, hydrocarbon residue,

[0118] R 5' can 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 the sum of c' + e' is equal to 0 or 1 in at least 40% of the units of formula (II).

[0119] Suitable silicone resins preferably consist of at least 90 wt.% units of formula (II), particularly preferably exclusively of units of formula (II).

[0120] Examples of residues R 3' 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.

[0121] Examples of substituted residues R 3' are halogenalkyl groups, such as the 3,3,3-trifluoro-n-propyl group, the 2,2,2,2',2',2'-hexafluoroisopropyl group and the heptafluoroisopropyl group, and halogenaryl groups, such as the o-, m- and p-chlorophenyl group.

[0122] Preferably, the remainder is R. 3 ' by means of monovalent hydrocarbon residues with 1 to 6 carbon atoms, optionally substituted with halogen atoms, particularly preferably by means of alkyl residues with 1 or 2 carbon atoms, especially by means of the methyl residue. The residue R may be 3 'but they can also be divalent aliphatic residues that link two silyl groups of formula (II) together, such as alkylene residues with 1 to 10 carbon atoms, such as methylene, ethylene, propylene or butylene residues.

[0123] Preferably, the remainder is R. 3' however, monovalent SiC-bonded aliphatic hydrocarbon residues with 1 to 18 carbon atoms, optionally substituted with halogen atoms, particularly preferably aliphatic hydrocarbon residues with 1 to 6 carbon atoms, especially the methyl residue.

[0124] Examples of remainder R 4 ' are hydrogen atoms or those responsible for the remainder R 3 'Examples given.

[0125] Preferably, the remainder is R. 4 ' alkyl groups with 1 to 10 carbon atoms substituted around a hydrogen atom or optionally with halogen atoms, particularly preferably around alkyl groups with 1 to 4 carbon atoms, especially around the methyl and ethyl group.

[0126] Examples of residues R 5 ' are the ones above for R 3 ' specified aromatic residues.

[0127] Preferably, the remainder is R. 5'around optionally substituted with halogen atoms, SiC-bonded aromatic hydrocarbon residues with 1 to 18 carbon atoms, such as ethylphenyl, toluyl, xylyl, chlorophenyl, naphtyl or styryl residues, particularly preferably around the phenyl residue. Silicone resins are preferably used in which at least 90% of all residues are R 3 ' for methyl group, at least 90% of all R groups 4 ' for methyl, ethyl, propyl or isopropyl residues and at least 90% of all residues R 5 ' stands for phenyl residue.

[0128] 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).

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] Examples of silicone resins are organopolysiloxane resins, which consist essentially, preferably exclusively, of (Q) units of the formulas SiC>4 / 2, Si(OR 4 ')C>3 / 2, Si(OR 4 ')2C>2 / 2 and Si(OR 4 ')3Oi / 2, (T)-units of the formulas PhSiC>3 / 2, PhSi(OR 4 ')O2 / 2, PhSi(OR 4 ')2Oi / 2, MeSiC>3 / 2, MeSi(OR 4 ')C>2 / 2 and MeSi(OR 4 ')2Oi / 2 (D)-units of the formulas Me2SiC>2 / 2, Me2Si(OR 4 ')Oi / 2, Ph2SiO2 / 2 and Ph2Si(OR 4')Oi / 2, MePhSiC>2 / 2 and MePhSi(OR 4 ')Oi / 2 and (M) units of the formula MesSiOi^, where Me represents a methyl group, Ph a phenyl group and R 4 ' for hydrogen atom or optionally substituted with halogen atoms alkyl groups with 1 to 10 carbon atoms, particularly preferably around 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.

[0135] Preferred examples of silicone resins are organopolysiloxane resins consisting essentially, preferably exclusively, of T-units of the formulas PhSiO3 / 2, PhSi(OR 4 ')O2 / 2 and PhSi(OR 4 ')2Oi / 2, T-units of the formulas MeSiO3 / 2, MeSi(OR 4 ')O2 / 2 and MeSi(OR 4 ')2Oi / 2 as well as D units of the formulas Me2SiO2 / 2 and Me2Si(OR 4 ')Oi / 2 consist of Me for a methyl group, Ph for a phenyl group and R 4' for a hydrogen atom or optionally substituted with halogen atoms 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 of 0.5 to 2.0.

[0136] Among these examples, silicone resins are particularly preferred whose units of formula (II) consist of at least 50%, preferably at least 70%, and in particular at least 85% of T-units of formulas PhSiC>3 / 2, PhSi(OR 4 ')C>2 / 2, PhSi(OR 4 ')2Oi / 2, Me SiOs / 2, MeSi(OR 4 ')C>2 / 2 and MeSi(OR 4 ')2Oi / 2 are formed, wherein these silicone resins contain at least 30%, preferably at least 40%, in particular at least 50% T-units of formulas PhSiC>3 / 2, PhSi(OR 4 ')C>2 / 2 and PhSi(OR 4 ')2Oi / 2 and at least 10%, preferably at least 15%, in particular at least 20% T-units of MeSiOs / 2, MeSi(OR 4 ')C>2 / 2 and MeSi(OR4 ')2Oi / 2 contained. 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.

[0137] Such silicone resins can be both solid and liquid at 23°C and 1000 hPa, with silicone resins preferably being liquid.

[0138] 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.

[0139] Furthermore, the reactive hot melt adhesive composition according to the present invention can additionally contain at least one tackifier. One tackifier or, for example, two or three different tackifiers can be used. The proportion is advantageously up to 65 wt.%, for example from 0.01 wt.% to 65 wt.%, and more preferably in the range of up to 15 wt.%, for example from 0.01 wt.% to 15 wt.%, based on the total weight of the composition.

[0140] Furthermore, the reactive hot melt adhesive composition according to the present invention can additionally contain at least one stabilizer. This stabilizer can be one, two, three, or four. Stabilizers are known to those skilled in the art. They can include, among others, antioxidants, sterically hindered amines as light stabilizers, UV absorbers, or water scavengers. The proportion is advantageously up to 2 wt.%, for example, from 0.01 wt.% to 2 wt.%, and more preferably in the range of 0.4 wt.% to 0.8 wt.%, based on the total weight of the composition.

[0141] The reactive hot melt adhesive composition according to the invention further comprises a component b). This component is at least one silane-terminated polyurethane that is not an alpha-silane-terminated polyurethane. Thus, component b) can comprise one or more, such as two, three, or four, such silane-terminated polyurethanes. Preferably, component b) consists of only one component. The proportion of component b) is 20 wt.% to 96.999 wt.% based on the total weight of the hot melt adhesive composition according to the invention. Preferably, the proportion is 50 wt.% to 90 wt.%. More preferably, the proportion is 61 wt.%.

[0142] The at least one silane-terminated polyurethane b), which is not an alpha-silane-terminated polyurethane, is obtained by a reaction in which at least one polyol (1) reacts with at least one polyisocyanate (2), optionally in the presence of at least one chain terminator (3), to form a polyurethane prepolymer, which is further reacted with at least one secondary aminosilane (4), which is not an alpha-aminosilane, such that the free isocyanate content is less than 0.1 wt%, preferably less than 0.001 wt%, based on the total weight of the silane-terminated polyurethane b), and wherein the following proportions result based on the sum of the reactants (1), (2), (3) and (4):

[0143] 1) 40% to 85% by weight of at least one polyol;

[0144] 2) 10 wt.% to 50 wt.% of the at least one polyisocyanate;

[0145] 3) 0 wt.% to 25 wt.% of the at least one chain breaker;

[0146] 4) 1 wt.% to 15 wt.% of at least one secondary aminosilane that is not an alpha-aminosilane.

[0147] Preferably, the following proportions result with respect to the sum of reactants (1), (2), (3) and (4): Preferably, the proportion of the at least one polyol is 50 wt.% to 70 wt.%. Preferably, the proportion of the at least one polyisocyanate is 25 wt.% to 40 wt.%. Preferably, the proportion of the at least one chain terminator is 2 wt.% to 10 wt.%. Preferably, the proportion of the at least one secondary aminosilane, which is not an alpha-aminosilane, is 5 wt.% to 10 wt.%.

[0148] Preferably, the isocyanate content of the polyurethane prepolymer is between 0.5 wt.% and 5 wt.%, preferably between 0.8 wt.% and 1.5 wt.%.

[0149] Component b) is obtained from a reaction in which at least one polyol (1) reacts with at least one polyisocyanate (2), optionally in the presence of at least one chain terminator (3), to form a polyurethane prepolymer, which is then reacted in a further reaction with at least one secondary aminosilane (4), which is not an alpha-aminosilane. At least one polyisocyanate is used in the reaction. Here, the prefix "poly" means that at least two (diisocyanate) isocyanate groups are present in the molecule. More than two, such as three, four, five, or a plurality of more than five isocyanate groups, may also be present. Preferably, the at least one polyisocyanate (2) is at least one diisocyanate. One or more, such as two, three, or four, polyisocyanates may be used.

[0150] Suitable diisocyanates include methylenediphenyl diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, diisocyanatodicyclohexylmethane, isophorone diisocyanate, toluene diisocyanate, and naphthylene diisocyanate, optionally including their isomers and homologs. Methylenediphenyl diisocyanates (MDI) are preferred, with the isomer diphenylmethane-2,4'-diisocyanate or a mixture with other MDI isomers being particularly preferred, wherein the proportion of diphenylmethane-2,4'-diisocyanate is preferably at least 45%. The advantage of using a high content of diphenylmethane-2,4'-diisocyanate is due to a shorter chain structure during prepolymerization. A short-chain prepolymer leads to lower viscosities, and the products formulated with it are thus easier to process. Chemical modifications or oligomeric addition or condensation products of the aforementioned diisocyanates may also be suitable.Examples include carbodiimide-linked diisocyanates, commercially available under the trade name Desmodur® CD-S, and uretdione-linked diisocyanates, commercially available under the trade name Desmodur® N 3400. The use of mixtures of these diisocyanates with each other, as well as mixtures with isomers and higher-functionality homologs, such as a mixture of diphenylmethane-4,4'-diisocyanate with isomers and higher-functionality homologs (polymeric MDI), commercially available under the trade name Desmodur® VK 5, is also conceivable.

[0151] The reaction uses at least one polyol. The prefix "poly" indicates that the molecule contains at least two hydroxyl groups (diols). More than two hydroxyl groups are also possible, such as three, four, five, or a multitude of more than five. One or more polyols, such as two, three, or four, can be used. Suitable polyols include polyether polyols, hydroxyl-functional polyacrylates, and monomeric polyols such as 1,4-butanediol and mixtures of these polyols. Polypropylene glycols, polybutylene glycols, and polyether polyols produced from ethylene and propylene oxides are preferred polyether polyols. A small proportion of polyethylene glycols or other polyols, up to a mass fraction of 15%, is also acceptable. Polyether polyols produced via either KOH- or dimetal complex-catalyzed polymerization can be used.The average molecular weight of the polyether polyols can be up to 16,000 g / mol. Particularly preferably, the average molecular weight is above 60%, more preferably above 80%, and most preferably above 90% of the polyether polyols used, with a molecular weight below 2,000 g / mol. The use of relatively low molecular weight polyols results in the formation of many polyurethane units during prepolymerization, which interact with each other, among other things, via hydrogen bonds. This interaction is more pronounced at room temperature than at processing temperature. The products formulated in this way thus exhibit relatively high initial strength at room temperature and low viscosity during processing.

[0152] Polyacrylates with reactive functional hydroxyl groups, types with an OH number of less than 10 mg KOH / g have proven to be advantageous; these are commercially available, for example, under the trade name Dianal MB-2876.

[0153] The polyols used have an average functionality of less than 3. The acid number of the polyols used is preferably below 8 mg KOH / g, particularly preferably below 0.1 mg KOH / g (ASTM D4662).

[0154] The reaction may involve the use of at least one chain terminator. It can be one or more, such as two, three, or four chain terminators.

[0155] Suitable chain terminators are compounds that possess a functional group capable of reacting with an isocyanate group. A hydroxyl group is preferred as the functional group. Examples of suitable chain terminators are dipropylene glycol monomethyl ether and propylene glycol 1-phenyl ether.

[0156] The reaction uses at least one secondary aminosilane that is not an alpha-aminosilane. One or more aminosilanes, such as two, three, or four, can be used. For example, N-cyclohexyl-3-aminopropyltrimethoxysilane, commercially available under the trade name Geniosil® GF 92, is a suitable secondary aminosilane. In particular, silanes containing secondary amine groups, such as those described as component d) herein, are suitable.

[0157] Another object of the present invention is a method for producing a reactive hot melt adhesive composition according to the invention, comprising steps

[0158] (a) Production of at least one silane-terminated polyurethane b);

[0159] (b) Mixing the at least one silane-terminated polyurethane (b) from step (a) with the at least one alpha-silane-terminated organic polymer (a);

[0160] (c) If necessary, adding at least one filler c); and

[0161] (d) Addition of at least one silane d), which has a primary or secondary amino group or a blocked amino group which hydrolyzes to the primary or secondary amino group.

[0162] Finally, another object of the present invention is a method for surface lamination comprising the step of applying a reactive hot melt adhesive composition according to the invention to a substrate, preferably to a substrate with a polar surface, using an application roller.

[0163] 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.

[0164] Surprisingly, it has been shown that the coating applied using a roller coating machine can be cleaned even after the roller stability period has expired, i.e., when the binder exhibits noticeable stringing during processing, which determines the coating appearance. Accordingly, a further object of the present invention is the use of a reactive hot-melt adhesive composition according to the invention for roller coating.

[0165] 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.

[0166] The following advantages are particularly evident:

[0167] Isocyanate-free, good adhesion spectrum, especially on metals, glass and other materials. No foaming due to CO2 formation.

[0168] The present invention is explained in more detail with reference to the following examples, although the invention is not limited to these embodiments.

[0169] Examples

[0170] Example 1a: Synthesis of a polyurethane prepolymer according to the invention.

[0171] 50 g of dipropylene glycol monomethyl ether are placed in a planetary mixer with a dissolver agitator together with 461 g of Caradol ED 260-02 (polypropylene glycol 400) and 80 g of Caradol ED56-200 (polypropylene glycol 2000) and heated to 100 °C. Then, 349 g of Lupranat® MIS (mixture of 2,4'- and 4,4'-diphenylmethane diisocyanate) is added and stirred under vacuum at 50 mbar until the mixture is homogeneous and has a residual isocyanate content of approximately 1% (see Table 1a). Table 1a: Composition of the polyurethane prepolymer precursor

[0172] Example 1b: Synthesis of a silane-terminated polyurethane according to the invention

[0173] 940 g of polyurethane prepolymer from example aa are placed, 60 g of Geniosil® GF 92 are added and stirred at 800 mbar for 5 minutes (see Table Ib).

[0174] Table 1b: Composition of the silane-terminated polyurethane VP9919 / 133.

[0175] Example 1c: Production of an adhesive formulation according to the invention

[0176] 608 g of silane-terminated polyurethane from Example 1b and 80 g of Geniosil® STP-E 10 are mixed in a planetary mixer with a butterfly agitator under vacuum (50 mbar) at 100 °C. Subsequently, 300 g of Calcit MX 30 are added portionwise while stirring, and the mixture is degassed under vacuum at 50 mbar for 10 minutes. Finally, 4 g of Dynasylan® 1146 are added to this mixture and stirred at 800 mbar for 5 minutes (see Table 1c). Table 1c: Composition and physicochemical properties of the silane-terminated polyurethane hot melt adhesive.

Claims

Patent claims 1. Reactive hot melt adhesive composition, based on the total weight of the composition, containing: a) 3 wt.% to 79.999 wt.% of at least one alpha-silane-terminated organic polymer; b) 20 wt.% to 96.999 wt.% of at least one silane-terminated polyurethane that is not an alpha-silane-terminated polyurethane; c) 0 wt.% to 70 wt.% of at least one filler; d) 0.001 wt.% to 3 wt.% of...-% of at least one silane having a primary or secondary amino group or a blocked amino group hydrolyzed to the primary or secondary amino group; wherein the at least one silane-terminated polyurethane b), which is not an alpha-silane-terminated polyurethane, is obtained by a reaction in which at least one polyol (1) reacts with at least one polyisocyanate (2), optionally in the presence of at least one chain terminator (3), to form a polyurethane prepolymer which is further reacted with at least one secondary aminosilane (4), which is not an alpha-aminosilane, such that the free isocyanate content is less than 0.1 wt% based on the total weight of the silane-terminated polyurethane b), and wherein the following proportions are obtained based on the sum of the reactants (1), (2), (3) and (4):. 1) 40% to 85% by weight of at least one polyol; 2) 10 wt.% to 50 wt.% of the at least one polyisocyanate; 3) 0 wt.% to 25 wt.% of the at least one chain breaker; 4) 1 wt.% to 15 wt.% of at least one secondary aminosilane that is not an alpha-aminosilane.

2. Reactive hot melt adhesive composition according to claim 1, characterized in that the composition is free of one or more acrylate resin-based polymers that are not alpha-silane-terminated organic polymers.

3. Reactive hot melt adhesive composition according to claim 1 or 2, characterized in that the composition comprises 50 wt.% to 90 wt.% of the at least one silane-terminated polyurethane, which is not an alpha-silane-terminated polyurethane.

4. Reactive hot melt adhesive composition according to one or more of claims 1 to 3, characterized in that the composition contains 5 wt.% to 10 wt.% of the at least one alpha-silane-terminated organic polymer.

5. Reactive hot melt adhesive composition according to one or more of claims 1 to 4, characterized in that the composition comprises 0.3 wt.% to 1.2 wt.% of at least one silane comprising a primary or secondary amino group or a blocked amino group which hydrolyzes to the primary or secondary amino group.

6. Reactive hot melt adhesive composition according to one or more of claims 1 to 5, characterized in that the composition contains one or more fillers and optionally one or more further components.

7. Reactive hot melt adhesive composition according to claim 6, characterized in that the proportion of the at least one filler is up to 70 wt.%, preferably up to 35 wt.%.

8. Reactive hot melt adhesive composition according to one or more of claims 1 to 7, characterized in that at least one component is a stabilizer, preferably with up to 2 wt.%, more preferably 0.4 to 0.8 wt.%, based on the composition.

9. Reactive hot melt adhesive composition according to one or more of claims 1 to 8, characterized in that at least one component is a resin, for example a tackifying resin, preferably with up to 65 wt.%, more preferably up to 15 wt.%, based on the composition.

10. Reactive hot melt adhesive composition according to one or more of claims 1 to 9, characterized in that the at least one polyisocyanate (2) is a diisocyanate.

11. Reactive hot melt adhesive composition according to one or more of claims 1 to 10, characterized in that the isocyanate content of the polyurethane prepolymer is 0.5 wt.% to 5 wt.%, preferably 0.8 wt.% to 1.5 wt.%.

12. Reactive hot melt adhesive composition according to one or more of claims 1 to 11, characterized in that the proportion of the at least one polyol is 50 wt.% to 70 wt.%.

13. Reactive hot melt adhesive composition according to one or more of claims 1 to 12, characterized in that the proportion of the at least one polyisocyanate is 25 wt.% to 40 wt.%.

14. Reactive hot melt adhesive composition according to one or more of claims 1 to 13, characterized in that the proportion of the at least one chain breaker is 2 wt.% to 10 wt.%.

15. Reactive hot melt adhesive composition according to one or more of claims 1 to 14, characterized in that the proportion of the at least one secondary aminosilane, which is not an alpha-aminosilane, is 5 wt.% to 10 wt.%.

16. Reactive hot melt adhesive composition according to one or more of claims 1 to 15, characterized in that the at least one alpha-silane-terminated organic polymer comprises 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 exhibits, whereby X for O or N(R 5 ) stands; R, R 1 , R 2 and R 5independently of each other they stand for hydrogen or a hydrocarbon residue with 1 to 20 carbon atoms; R 3 and R 4 independently of each other, they represent a hydrocarbon residue with 1 to 20 carbon atoms; a represents 0, 1 or 2 and characterizes the bond for attachment to the polymer.

17. Reactive hot melt adhesive composition according to one or more of claims 1 to 16, characterized in that the organic polymer of the at least one alpha-silane-terminated organic polymer is a polyoxyalkylene, a hydrocarbon polymer, a polyurethane, a polyester, a polyamide, a polyacrylate, a polymethacrylate or a polycarbonate.

18. Reactive hot melt adhesive composition according to one or more of claims 1 to 17, characterized in that the at least one silane comprising a primary or secondary amino group or a blocked amino group which hydrolyzes to the primary or secondary amino group is a low molecular weight silane, preferably with a molecular weight in the range of 100 to 500 g / mol.

19. Reactive hot melt adhesive composition according to one or more of claims 1 to 18, characterized in that the at least one silane, which has a primary or secondary amino group or a blocked amino group which hydrolyzes to the primary or secondary amino group, is an oligomeric silane containing one or more amino groups, preferably with a molecular weight of more than 500 g / mol and preferably a mixture of amino group-containing alkoxy / hydroxy silanes and / or silanols and condensation and co-condensation products based thereon.

20. A method for producing a reactive hot melt adhesive composition according to one or more of claims 1 to 19, comprising the steps (a) Producing at least one silane-terminated polyurethane (b), which is not an alpha-silane-terminated polyurethane, by a reaction in which at least one polyol (1) reacts with at least one polyisocyanate (2), optionally in the presence of at least one chain terminator (3), to form a polyurethane prepolymer, which is further reacted with at least one secondary aminosilane (4), which is not an alpha-aminosilane, such that the content of free isocyanate is less than 0.1 wt% based on the total weight of the silane-terminated polyurethane (b), wherein the following proportions are obtained in relation to the sum of the reactants (1), (2), (3) and (4): 1) 40% to 85% by weight of at least one polyol; 2) 10 wt.% to 50 wt.% of the at least one polyisocyanate; 3) 0 wt.% to 25 wt.% of the at least one chain breaker; 4) 1% by weight to 15% by weight of at least one secondary aminosilane that is not an alpha-aminosilane; (b) Mixing the at least one silane-terminated polyurethane (b) from step (a) with the at least one alpha-silane-terminated organic polymer (a); (c) If necessary, adding at least one filler c); and (d) Addition of at least one silane d), comprising a primary or secondary amino group or a blocked amino group which hydrolyzes to the primary or secondary amino group.

21. Surface lamination process comprising the step Applying a reactive hot melt adhesive composition according to one of claims 1 to 19 to a substrate using an application roller.

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