HK1174651B - Polyurethan-prepolymere - Google Patents

Description

Polyurethane prepolymers

The present invention relates to polyurethane prepolymers, to a process for their preparation and to their use as binders for adhesives, coatings or foams.

Alkoxysilane-functional polyurethanes which crosslink by silane polycondensation have been known for a long time. A review article on this subject is, for example, referred to "AdhesivesAge" 4/1995, page 30 onwards (author: Ta-Min Feng, B.A. Waldmann). Such alkoxysilane-terminated moisture-curing one-component polyurethanes are increasingly used in the construction and automotive industry as flexible (weichelalastisch) coatings, sealants and mastics.

Such alkoxysilane-functional polyurethanes can be prepared, for example, according to U.S. Pat. No. 3,627,722 or DE-A1745526 in the following manner: the polyether polyol is reacted with an excess of polyisocyanate to give an NCO-containing prepolymer which is then further reacted with an amino-functional alkoxysilane.

The publications EP-A0397036, DE-A19908562 (corresponding to EP-A1093482) and U.S. Pat. No. 3, 2002/0100550 describe further different processes for preparing alkoxysilane-terminated polymers. According to those documents, high molecular weight polyethers having an average molecular weight of 4000g/mol or more are used in each case.

The application EP-A0070475 describes the preparation and use of polymers terminated by alkoxysilanes terminated with NCO-functional alkoxysilanes starting from hydrogen-acidic prepolymers. Polyols having a molar weight of 500-6000 g/mol were used for the prepolymer synthesis. The polymers described therein are used as sealant formulations, that is to say adhesives in flexible elastomer systems (Bindimittel).

A similar process is described in application DE-A102007058344.

After curing, all these alkoxysilane-terminated systems form soft elastic polymers with relatively low strength and high elongation at break. DE-A1745526 describes, for polypropylene oxide glycol-based polymers, 3.36 kg/cm²－28.7kg/cm²The tensile strength of (2). High strength sufficient for structural bonding can only be achieved with crystalline polycaprolactone.

However, this system is very highly viscous or solid at room temperature and can therefore only be processed in the hot state.

The fields of use of the above-mentioned applications are therefore limited on the one hand to sealing materials and soft elastic adhesives and on the other hand to highly viscous or solid systems which can only be processed in the hot state.

It is therefore an object underlying the present invention to provide alkoxysilane-terminated polyurethanes which are liquid at room temperature and achieve high cohesive strength after curing so that they can be used to formulate adhesives which allow structural adhesion.

It has now been found that such alkoxysilane-terminated polyurethanes can be prepared by: a prepolymer containing isocyanate-reactive hydrogen is first prepared from a mixture of a polyisocyanate and a compound having groups reactive with isocyanates. The mixture of compounds having groups which are reactive toward isocyanates therefore comprises low molecular weight polyfunctional isocyanate-reactive compounds having a molecular weight of 500g/mol or less in an amount of from 1 to 40% by weight. Finally, the resulting prepolymer containing isocyanate-reactive hydrogens is modified with an isocyanate-functional alkoxysilane.

The present invention therefore provides polymers modified with alkoxysilane groups which can be obtained by reacting:

a) isocyanate-reactive hydrogen containing prepolymers comprising structural units of the general formula (I)

Wherein

PIC represents the residue (Rest) of the polyisocyanate (B) minus the isocyanate group,

Y¹represents nitrogen, oxygen or sulfur,

R¹represents a free electron pair or hydrogen or any organic residue,

a represents the residue of an isocyanate-reactive polymer and a low molecular weight polyfunctional isocyanate-reactive compound minus the isocyanate-reactive groups, said A being derived from a structural element of the formula

–Y²–(C=O)–NH–PIC–NH–(C=O)–Y¹(R¹)– ,

Wherein Y is¹And Y²Independently of one another, represent nitrogen, oxygen or sulfur,

low molecular weight polyfunctional isocyanate-reactive compounds (A1) and polyether polyols, polyester polyols, polycarbonate polyols or polytetrahydrofuran polyols (A2) in any desired sequence, that is to say block-, alternating-or randomly linked to one another,

wherein all or part of the terminal groups of those substructures can also be the corresponding thio compounds or amine derivatives, wherein

From 1 to 40% by weight of a substructure A1 having an average molecular weight (Mn) of less than 500g/mol, and

60 to 99% by weight are substructures A2 having an average molecular weight (Mn) of more than 500g/mol,

and wherein A has an average functionality of from 2 to 6 as a whole,

and

b) an isocyanate-functional alkoxysilane compound of the general formula (II) (component C)

Wherein

Z¹、Z²And Z³Are identical or different C₁-C₈-alkoxy or C₁-C₈Alkyl residues, which can also be bridged, but in which at least one C must be present on each Si atom₁-C₈-an alkoxy residue,

q is a difunctional linear or branched organic group, preferably an alkylene residue having from 1 to 8 carbon atoms.

In this case, the reaction of b) with a) can be carried out in a ratio of from 0.8: 1.0 to 1.5: 1.0 (NCO: Y-H).

The compounds according to the invention are non-crystalline substances which are liquid at room temperature and have a number average molecular weight of less than 5000 g/mol, preferably less than 4000g/mol, and a viscosity of less than 700 Pas at 23 ℃, preferably less than 500 Pas at 23 ℃.

The isocyanate-reactive compound mixture (component A) consists of 1 to 40% of a low molecular weight, polyfunctional isocyanate-reactive compound (A1) having 2 to 6 isocyanate-reactive groups and a number average molecular weight of less than 500g/mol, and 60 to 99% of an isocyanate-reactive compound (A2) having 2 to 6 isocyanate-reactive groups and a number average molecular weight of more than 500g/mol, where both A1 and A2 may each consist of a combination of compounds having isocyanate-reactive groups, with the proviso that those compounds fall within the ranges mentioned above with respect to molecular weight.

As component a, any compound known to the person skilled in the art which contains isocyanate-reactive groups and has a functionality of on average at least 2 can be used. For a1, these may be, for example, low molecular weight polyfunctional isocyanate-reactive compounds, such as aliphatic polyols or polyamines, aromatic polyols or polyamines, and for a2, higher molecular weight isocyanate-reactive compounds, such as polyether polyols, polycarbonate polyols, polyester polyols and polythioether polyols. Preferably, such isocyanate-reactive compounds have an average functionality of from 2 to 6, preferably from 2 to 3.5 and particularly preferably from 2 to 3.

Preference is given to using polyhydric, preferably dihydric or trihydric, alcohols in component A1, for example ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1, 2-propanediol, 1,3-/1, 4-butanediol, 1,3-/1, 6-hexanediol, 1, 8-octanediol, neopentyl glycol, 1, 4-bis (hydroxymethyl) cyclohexane, bis (hydroxymethyl) tricyclo [5.2.1.02.6] decane or 1, 4-bis (2-hydroxyethoxy) benzene, 2-methyl-1, 3-propanediol, 2, 4-trimethylpentane-1, 3-diol, 2-ethyl-1, 3-hexanediol, dipropylene glycol, polypropylene glycol, dibutylene glycol, polybutylene glycol, 1, 4-phenoldimethanol, bisphenol A, tetrabromobisphenol A, Glycerol, trimethylolpropane, 1,2, 6-hexanetriol, 1,2, 4-butanetriol, pentaerythritol, p-cyclohexanediol, mannitol, sorbitol, methyl glycoside and 4,3, 6-dianhydrohexitol.

Suitable di-or triamines may be aliphatic amines, such as ethylenediamine, 1, 2-propylenediamine, 1, 3-propylenediamine, 1, 4-butylenediamine, neopentyldiamine, 1, 5-diamino-2-methylpentane (Dytek)^®A, DuPont), 2-butyl-2-ethyl-1, 5-pentanediamine, 1, 6-hexamethylenediamine, 2, 5-diamino-2, 5-dimethylhexane, 2, 4-and/or 2,4, 4-trimethyl-1, 6-diaminohexane, 1, 8-diaminooctane, 1, 11-diaminoundecane, 1, 12-diaminododecane, 4-aminomethyl-1, 8-octanediamine (triaminononane), diethylenetriamine, triethylenetetramine, cycloaliphatic amines, such as 1-amino-3, 3, 5-trimethyl-5-aminomethylcyclohexane (isophoronediamine, IPDA), TCD-diamine, 1, 4-cyclohexanediamine, hexamethylenediamine, mixtures thereof, 2, 4-and/or 2, 6-hexahydrotoluenediamine (H)₆TDA), isopropyl-2, 4-diaminocyclohexane and/or isopropyl-2, 6-diaminocyclohexane, tricyclodecanebis (methylamine), 1, 3-bis- (aminomethyl) -cyclohexane, 2,4 '-and/or 4,4' -diaminodicyclohexylmethane (PACM20), 3 '-dimethyl-4, 4' -diamino-dicyclohexylmethane (Laromin ™)^®C260, BASF AG, DE), isomers, i.e.diaminodicyclohexylmethane containing one methyl group as a substituent in the ring (e.g.C-monomethyl-diaminodicyclohexylmethane), 3(4) -aminomethyl-1-methylcyclohexylamine (AMCA), and araliphatic di-or triamines, e.g.1, 3-diaminobenzene, 1, 4-diaminobenzene, 2, 4-and/or 2, 6-diaminotoluene (TDA), 1, 3-bis- (aminomethyl) -benzene, 3, 5-diethyltoluene-2, 4-diamine, m-xylylenediamine, 4, 6-dimethyl-1, 3-xylylenediamine, 4 '-and/or 2,2' -Methylenedianiline (MDA), or amines containing hetero atoms, dimeric fatty acid diamines, bis- (3-aminopropyl) -methylamine, 4, 9-dioxadodecane-1, 12-diamine or 4,7, 10-trioxatridecane-1, 13-diamine.

Polyether polyols are preferably used in component A2. These can be obtained in a manner known per se by base catalysis or by alkoxylation of suitable starter molecules using double metal cyanides (DMC compounds). Suitable starter molecules for preparing polyether polyols are molecules having at least 2 elemental hydrogen bonds which are reactive with epoxides, or any mixture of such starter molecules.

Particularly suitable polyether polyols are those of the abovementioned type having an unsaturated end group content of less than or equal to 0.02 milliequivalents per gram of polyol (meq/g), preferably less than or equal to 0.015 meq/g, particularly preferably less than or equal to 0.01 meq/g (measurement method ASTM D2849-69).

This is described, for example, in US-A5158922 (e.g.Example 30) and EP-A0654302 (page 5, line 26 to page 6, line 32).

Suitable starter molecules for the preparation of polyether polyols are, for example, simple low molecular weight polyols, water, ethylene glycol, 1, 2-propanediol, 2-bis (4-hydroxyphenyl) propane, 1, 3-propanediol and 1, 4-butanediol, 1, 6-hexanediol, neopentyl glycol, 2-ethyl-1, 3-hexanediol, trimethylolpropane, glycerol, pentaerythritol, sorbitol, organic polyamines having at least two N-H bonds, such as triethanolamine, ammonia, methylamine or ethylenediamine, or any mixtures of these starter molecules. Alkylene oxides suitable for alkoxylation are, in particular, ethylene oxide and/or propylene oxide, which can be used in any order or also in mixtures for alkoxylation.

It is also possible to use polyether polyol mixtures comprising at least one polyol having at least one tertiary amino group. Such polyether polyols containing tertiary amino groups can be prepared by alkoxylation of starter molecules or at least starter molecule mixtures comprising starter molecules having at least 2 element-hydrogen bonds which are reactive toward epoxides, at least one of which is an NH bond, or low molecular weight polyol compounds having tertiary amino groups. Examples of suitable starter molecules are ammonia, methylamine, ethylamine, N-propylamine, isopropylamine, ethanolamine, diethanolamine, triethanolamine, ethylenediamine, ethylenetriamine, triethanolamine, N-methyldiethanolamine, ethylenediamine, N ' -dimethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 2, 4-tolylenediamine, 2, 6-tolylenediamine, aniline, diphenylmethane-2, 2' -diamine, diphenylmethane-2, 4' -diamine, diphenylmethane-4, 4' -diamine, 1-aminomethyl-3-amino-1, 5, 5-trimethylcyclohexane (isophoronediamine), dicyclohexylmethane-4, 4' -diamine, xylylenediamine and polyoxyalkyleneamines.

Polyether polyols in which the organic filler is dispersed, such as the addition product of toluene diisocyanate and hydrazine hydrate, or copolymers of styrene and acrylonitrile, may also be used.

Polytetramethylene ether glycols having a molecular weight of from 400g/mol to 4000g/mol, which are obtainable by polymerization of tetrahydrofuran, and also hydroxyl-containing polybutadienes may also be used.

By hydroxy polycarbonate is understood the reaction product of diols and/or triols of the ethylene glycol, diethylene glycol, 1, 2-propanediol, 1, 4-butanediol, neopentyl glycol or 1, 6-hexanediol type, for example glycerol, trimethylolpropane, pentaerythritol or sorbitol, with diphenyl carbonate and/or dimethyl carbonate. The reaction is a condensation reaction in which phenol and/or methanol are decomposed. Depending on the composition, liquid to waxy amorphous types with Tg values > 40 ℃ or crystalline polycarbonate polyols with a melting range of 40 to 90 ℃ are obtained. The molecular weight ranges from 200 g/mol to 10,000 g/mol. A molecular weight range of 400g/mol to 5000 g/mol is preferred. A molecular weight range of from 500g/mol to 3000 g/mol is particularly preferred.

Hydroxyl polyesters are understood to be the reaction products of: aliphatic, cycloaliphatic, aromatic and/or heterocyclic polybasic, but preferably dibasic carboxylic acids, for example adipic acid, azelaic acid, sebacic acid and/or dodecanedioic acid, phthalic acid, isophthalic acid, succinic acid, suberic acid, trimellitic acid, phthalic anhydride, tetrahydrophthalic anhydride, glutaric anhydride, tetrachlorophthalic anhydride, endomethyleneic anhydrideTetrahydrophthalic anhydride, maleic acid, fumaric acid, dimeric and trimeric fatty acids, optionally in a mixture with monomeric fatty acids, for example oleic acid, dimethyl terephthalate or bisglycol terephthalate, o-, m-or terephthalic acid and polyhydric, preferably dihydric or trihydric alcohols, for example ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-/1, 3-propanediol and 1,4-/1, 3-butanediol, 1, 6-hexanediol, 1, 8-octanediol, neopentyl glycol, 1, 4-bis (hydroxymethyl) cyclohexane, bis (hydroxymethyl) tricyclo [5.2.1.0^2.6]Decane or 1, 4-bis (2-hydroxyethoxy) benzene, 2-methyl-1, 3-propanediol, 2, 4-trimethylpentanediol, 2-ethyl-1, 3-hexanediol, dipropylene glycol, polypropylene glycol, dibutylene glycol, polybutylene glycol, 1, 4-phenoldimethanol, bisphenol A, tetrabromobisphenol A, glycerol, trimethylolpropane, 1,2, 6-hexanetriol, 1,2, 4-butanetriol, pentaerythritol, p-cyclohexanediol, mannitol, sorbitol, methyl glycoside or 4,3, 6-dianhydrohexitol. Instead of the free polycarboxylic acids, it is also possible to prepare polyesters by concomitant use of the corresponding polycarboxylic anhydrides or corresponding polycarboxylic esters of lower alcohols, or mixtures thereof.

The reaction is a usual melt condensation, as described in Ullmanns Enzyklop ä die der technischen Chemie, "Polyester", 4 th edition, Verlag Chemie, Weinheim, 1980. Depending on the composition, a liquid amorphous type with a Tg value of >20 ℃ or a crystalline polyester polyol with a melting range of 40-90 ℃ is obtained. The polyester polyols which can be used according to the invention have a number average molecular weight of from 500g/mol to 2500 g/mol, preferably from 800g/mol to 2000 g/mol.

Mention may also be made here in particular of products derived from the reaction product of glycerol and hydroxy fatty acids, in particular castor oil, and derivatives thereof, for example mono-dehydrated castor oil.

The corresponding hydroxy-terminated poly-caprolactone may also be used.

In addition to the polyhydroxyl compounds, it is also possible to use polyetheramines in part in component A. With regard to the preferred molecular weights and the composition of the mixture, the same ranges already described for the polyether polyols apply.

Before the actual prepolymerization, the above-mentioned isocyanate-reactive compounds can be reacted with all aromatic as well as aliphatic polyisocyanates to give urethane-modified hydroxyl compounds.

As component B, aromatic, aliphatic and cycloaliphatic diisocyanates and mixtures thereof come into consideration. Suitable diisocyanates are those of the formula PIC (NCO) having an average molecular weight of less than 400g/mol₂Wherein PIC represents aromatic C₆-C₁₅-hydrocarbon radical, aliphatic C₄-C₁₂-hydrocarbon or alicyclic C₆-C₁₅Hydrocarbon radicals, such as diisocyanates selected from the following groups: butane diisocyanate, pentane diisocyanate, hexane diisocyanate (hexamethylene diisocyanate, HDI), 4-isocyanatomethyl-1, 8-octane diisocyanate (triisocyanatononane, TIN), 4' -methylenebis (cyclohexyl isocyanate), 3,5, 5-trimethyl-1-isocyanato-3-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 2, 4-and/or 2, 6-methylcyclohexyl diisocyanate (H)₆TDI) and omega, omega' -diisocyanato-1, 3-dimethylcyclohexane (H)₆XDI), Xylylene Diisocyanate (XDI), 4 '-diisocyanatodicyclohexylmethane, tetramethylene diisocyanate, 2-methylpentamethylene diisocyanate, 2, 4-trimethylhexamethylene diisocyanate (THDI), dodecamethylene diisocyanate, 1, 4-diisocyanatocyclohexane, 4' -diisocyanato-3, 3 '-dimethyl-dicyclohexylmethane, 4' -diisocyanatodicyclohexylpropane- (2,2), 3-isocyanatomethyl-1-methyl-1-isocyanatocyclohexane (MCI), 1, 3-diisocyanatooctyl-4-methylcyclohexane, 1, 3-diisocyanato-2-methylcyclohexane and alpha, α, α ', α' -tetramethyl-m-or-p-xylylene diisocyanate (TMXDI), 2,4-/2, 6-Tolylene Diisocyanate (TDI), methylene diphenyl diisocyanate (MDI), Naphthyl Diisocyanate (NDI). Preference is given to using IPDI, HDI or TDI or MDI derivatives.

All or part of the above-mentioned organic aliphatic, cycloaliphatic or heterocyclic polyisocyanates can also be used in the form of their derivatives, such as urethanes, biurets, allophanates, uretdiones, isocyanurates and trimers, and also in the form of mixtures of those derivatizations.

In principle, it is also possible to use mixtures of a plurality of polyisocyanates, but preferably only one polyisocyanate is used.

Suitable isocyanate-functional alkoxysilane compounds of the general formula (II) (component C) are in principle all monoisocyanates containing alkoxysilane groups having a molecular weight of from 140 g/mol to 500 g/mol. Examples of such compounds are isocyanatomethyltrimethoxysilane, isocyanatomethyltriethoxysilane, (isocyanatomethyl) methyldimethoxysilane, (isocyanatomethyl) methyldiethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropylmethyldimethoxysilane, 3-isocyanatopropyltriethoxysilane and 3-isocyanatopropylmethyldiethoxysilane. Preference is given to using 3-isocyanatopropyltrimethoxysilane.

According to the invention, it is also possible to use isocyanate-functional silanes, as described in U.S. Pat. No. 4,4,146,585 or EP-A1136495, which are prepared by reacting diisocyanates with aminosilanes or thiosilanes.

The present invention further provides a process for preparing polymers modified with alkoxysilane groups according to the description above, in which a mixture of isocyanate-reactive compounds (component A) is first reacted with a polyisocyanate (component B) to give a prepolymer containing isocyanate-reactive hydrogens, which is subsequently masked by reaction with an isocyanate-functional alkoxysilane (component C).

For the synthesis of prepolymers containing isocyanate-reactive hydrogens, an excess of component A is used, preferably an NCO: Y ratio of 1.0: 1.3 to 1.0: 3.0, particularly preferably 1.0: 1.5 to 1.0: 2.0, is selected¹-H ratio.

The carbamation can be accelerated by catalysis. Carbamation catalysts known per se to the person skilled in the art, such as organotin compounds or amine catalysts, are suitable for accelerating the NCO-OH reaction. Examples of organotin compounds which may be mentioned are: dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin bisacetylacetonate and tin carboxylates, such as tin octoate. The tin catalysts mentioned may optionally be used in combination with amine catalysts, for example aminosilane or 1, 4-diazabicyclo [2.2.2] octane.

Particular preference is given to using dibutyltin dilaurate as carbamation catalyst.

In the process according to the invention, the catalyst component, in the case of concomitant use, is used in an amount of from 0.001% by weight to 5.0% by weight, preferably from 0.001% by weight to 0.1% by weight and particularly preferably from 0.005% by weight to 0.05% by weight, based on the solids content of the process product.

The carbamation of components A and B is carried out at temperatures of from 20 ℃ to 200 ℃, preferably from 40 ℃ to 140 ℃ and particularly preferably from 60 ℃ to 120 ℃.

The reaction is continued until complete conversion of the isocyanate-reactive groups is achieved. The progress of the reaction is expediently monitored by checking the NCO content and is ended when the corresponding theoretical NCO content is reached and is constant. This can be followed by means of suitable measuring instruments installed in the reaction vessel and/or by analysis of the samples taken. Suitable methods are known to those skilled in the art. They are, for example, viscosity measurements, measurements of the NCO content, refractive index measurements, OH content measurements, Gas Chromatography (GC), nuclear magnetic resonance spectroscopy (NMR), infrared spectroscopy (IR) and near infrared spectroscopy (NIR). The NCO content of the mixture is preferably measured by titration.

It is immaterial whether the process according to the invention is carried out continuously, for example in a static mixer, extruder or kneader, or discontinuously, for example in a stirred reactor.

The process according to the invention is preferably carried out in a stirred reactor.

The further reaction of the prepolymer containing isocyanate-reactive hydrogens with the isocyanate-functional alkoxysilane (component C) is carried out as described in EP-B1924621 at a temperature in the range from 20 ℃ to 200 ℃, preferably from 40 ℃ to 120 ℃ and particularly preferably from 60 ℃ to 100 ℃, with the proportions generally being selected such that an excess of NCO groups is used, which are captured at the end by compounds reactive toward isocyanates or by allophanatization.

The invention further provides adhesives, coatings or foams based on the polyurethane prepolymers according to the invention. The adhesive, coating or foam is crosslinked by silanol condensation polymerization under the action of atmospheric humidity. The prepolymers according to the invention are preferably used in adhesives, particularly preferably in adhesives exhibiting a viscosity of at least 5N/mm in accordance with DIN EN 14293²The tensile shear strength of (1).

To prepare such adhesives, coatings and foams, the polyurethane prepolymers containing alkoxysilane terminal groups according to the invention can be formulated in a known manner with the customary plasticizers, fillers, pigments, siccatives, additives, light stabilizers, antioxidants, thixotropic agents, catalysts, adhesion promoters (Haftvermitler) and optionally further auxiliary substances and additives.

Typical adhesive and coating formulations according to the invention comprise, for example, from 10% to 100% by weight of a polymer modified with alkoxysilane groups according to any one of claims 1 to 4, or a mixture of two or more such polymers modified with alkoxysilane groups, up to 30% by weight of a plasticizer or a mixture of two or more plasticizers, up to 30% by weight of a solvent or a mixture of two or more solvents, up to 5% by weight of a wet stabilizer or a mixture of two or more wet stabilizers, up to 5% by weight of a UV stabilizer or a mixture of two or more UV stabilizers, up to 5% by weight of a catalyst or a mixture of two or more catalysts, and up to 80% by weight of a filler or a mixture of two or more fillers.

Mention may be made, as examples of suitable fillers, of carbon black, precipitated silica, pyrogenic silica (Kiesels ä ure), mineral chalk and precipitated chalk. Mention may be made, as examples of suitable plasticizers, of phthalates, adipates, alkylsulfonates of phenol, phosphates and higher molecular weight polypropylene glycols.

Mention may be made, as thixotropic agents, by way of example, of pyrogenic silicon dioxide, polyamides, hydrogenated castor oil afterproducts and polyvinyl chloride.

Any organometallic compound and amine catalyst known to promote the polycondensation of silanes may be used as suitable catalysts for curing. Particularly suitable organometallic compounds are in particular tin and titanium compounds. Preferred tin compounds are, for example: dibutyltin diacetate, dibutyltin dilaurate, dioctyltin maleate and tin carboxylates, for example tin (II) octoate or dibutyltin bisacetylacetonate. The tin catalysts mentioned may optionally be used in combination with amine catalysts, for example aminosilane or 1, 4-diazabicyclo [2.2.2] octane. Preferred titanium compounds are, for example, alkyl titanates, such as diisobutyl-diacetoacetate ethyl ester-titanate. Particularly suitable for the use of the amine catalysts alone are those having a particularly high base strength, for example amines having an amidine structure. Thus preferred amine catalysts are, for example, 1, 8-diazabicyclo [5.4.0] undec-7-ene or 1, 5-diazabicyclo [4.3.0] non-5-ene.

As drying agents, mention may be made in particular of alkoxysilyl compounds, such as vinyltrimethoxysilane, methyltrimethoxysilane, isobutyltrimethoxysilane, hexadecyltrimethoxysilane.

As adhesion promoters, use is made of known functional silanes, for example aminosilanes of the type mentioned above and N-aminoethyl-3-aminopropyl-trimethoxy-and/or N-aminoethyl-3-aminopropyl-methyl-dimethoxysilane, epoxysilanes and/or mercaptosilanes.

Examples :

The following examples illustrate the invention without limiting it.

All percentages are given as weight percentages unless otherwise indicated.

The NCO content in% is determined on the basis of DIN EN ISO 11909 by back-titration with 0.1 mol/l hydrochloric acid after reaction with butylamine.

The viscosity measurements were carried out according to ISO/DIS 3219:1990 at a constant temperature of 23 ℃ and a constant shear rate of 250/sec, with the aid of a laminar rotational viscometer of the Physica MCR type (Anton Paar Germany GmbH, Ostfiltern, DE) using a measuring cone CP 25-1 (25 mm diameter, 1 ℃ cone angle).

The ambient temperature of 23 ℃ prevailing at the time of the test is called RT.

Examples 1 ( According to the invention ):

In a 5 liter sulfonation beaker with lid, stirrer, thermometer and nitrogen circulation, a mixture of 1428.3 g of polypropylene glycol having a hydroxyl number of 28 mg KOH/g and 198.4 g of tripropylene glycol having a hydroxyl number of 585 mg KOH/g is heated to 120 ℃. 141.4 g of hexamethylene diisocyanate (Desmodur) were then added^®H, Bayer MaterialScienceAG) and prepolymerization is carried out until the NCO content can no longer be detected by titration. 231.9 g of 3-isocyanatopropyltrimethoxysilane are then added at 120 ℃ and stirring is carried out until a theoretical NCO content of 0.05% is reached. Excess NCO was captured by addition of methanol. The resulting polyurethane prepolymer having alkoxysilane end groups had a viscosity (23 ℃ C.) of 98,100mPas and a number average molecular weight of 3500 g/mol.

Comparative example 1:

In a1 liter sulfonation beaker with lid, stirrer, thermometer and nitrogen circulation, 1758.8 g of a mixture of polypropylene glycols having a hydroxyl number of 56 mg KOH/g were heated to 120 ℃. 87.0 g of hexamethylene diisocyanate (Desmodur) were then added^®H, Bayer MaterialScienceAG) and prepolymerization is carried out until the NCO content can no longer be detected by titration. Then 154 was added at 120 ℃.2 g of 3-isocyanatopropyltrimethoxysilane and stirring until a theoretical NCO content of 0.05% is reached. Excess NCO was captured by addition of methanol. The resulting polyurethane prepolymer having alkoxysilane end groups had a viscosity of 56,500mPas (23 ℃) and a number average molecular weight of 3100 g/mol.

Measurement of skin formation time

The film was applied to a glass plate previously cleaned with ethyl acetate by means of a doctor blade (200 μm) and the plate was immediately inserted into a drying recorder. The needle was loaded with 10 g and moved over a distance of 35 cm in 24 hours.

The dry recorder was located in a climate chamber at 23 ℃ and 50% relative humidity of air.

The point at which the permanent trace of the needle disappeared from the film was defined as the skin formation time.

Application of the embodiments

To evaluate the application-related properties of the various polymers, they were processed in the following formulations:

	amount in% by weight
		Polymer and method of making same	46.06
Filler (Socal)® U1S2)	49.75
		Desiccant (Dynasylan)® VTMO)	2.76
Adhesion promoter (Dynasylan)® 1146)	1.38
		Catalyst (Lupragen)® N700)	0.05

To prepare the formulation, the filler (Socal) is added^®U1S2, Solvay GmbH) and desiccant (Dynasylan)^®VTMO; Evonik AG, germany) was added as a binder and mixed with a wall knife at 3000 rpm in a vacuum dissolver. Then add adhesion promoter (Dynasylan)^®1146, Evonik AG) and added with stirring at 1000 rpm over 5 minutes. Finally, the catalyst (Lupragen) is added with stirring at 1000 rpm^®N700, BASF SE, germany), and finally the final mixture was freed of air in vacuo.

For measuring physical properties, a separator having a thickness of 2 mm and a sample for measuring tensile shear strength were prepared. Tensile shear strength was measured using oak test specimens, which were stored at 23 ℃/50% air relative humidity for 7 days, then at 40 ℃ for 20 days, and then at 23 ℃/50% air relative humidity for 1 day.

The hardness of the films was measured according to DIN 53505 and the tensile shear strength was measured according to DIN EN 14293.

The following table shows the results obtained:

	comparative example 1	Example 1
			Shore D hardness	26	37
Tensile shear strength [ N/mm ]2]	3.1	7.3
			Time for epidermis formation [ min]	60	50。

Claims (11)

1. An isocyanate group-free polymer modified with alkoxysilane groups, which is liquid at room temperature, i.e. 23 ℃, having a number average molecular weight of less than 5000 g/mol, obtainable by reacting:

a) isocyanate-reactive hydrogen containing prepolymers comprising structural units of the general formula (I)

Wherein

PIC represents the residue of polyisocyanate (B) minus the isocyanate group,

　　　　Y₁represents nitrogen, oxygen or sulfur,

r1 represents a free electron pair or hydrogen or any desired organic residue,

a represents the residue of the isocyanate-reactive polymer and the low molecular weight polyfunctional isocyanate-reactive compound minus the isocyanate-reactive group, said A being derived from a structural element of the formula

–Y₂–(C=O)–NH–PIC–NH–(C=O)–Y₁(R1)–,

Wherein Y is₁And Y₂Independently of one another, represent nitrogen, oxygen or sulfur,

the low molecular weight polyfunctional isocyanate-reactive compound (A1) and the polyether polyol (A2) being linked to one another in any desired sequence, that is to say in blocks, alternately or randomly, are composed of residues which have been freed of isocyanate-reactive groups, wherein all or part of the terminal groups of these substructures A1 and A2 can also be the corresponding thio compounds or amine derivatives, wherein

From 1 to 40% by weight of a substructure A1 having an average molecular weight (Mn) of less than 500g/mol, and

60 to 99% by weight are substructures A2 having an average molecular weight (Mn) of more than 500g/mol,

and wherein A has an average functionality of from 2 to 6 as a whole,

and

b) an isocyanate-functional alkoxysilane compound of the general formula (II) (component C)

Wherein

　　　　Z₁、Z₂And Z₃Are identical or different C₁-C₈-alkoxy or C₁-C₈-alkyl residueA radical which can also be bridged, but in which at least one C must be present on each Si atom₁-C₈-an alkoxy residue,

q is an alkylene residue having 1 to 8 carbon atoms.

2. Polymer according to claim 1, characterized in that said polyether polyol (A2) is a polytetrahydrofuran polyol.

3. The polymer according to claim 1, having a number average molecular weight of less than 4000 g/mol.

4. The polymer according to claim 1, having a viscosity of less than 700 Pas at 23 ℃.

5. The polymer according to claim 1, having a viscosity of less than 500 Pas at 23 ℃.

6. Process for preparing polymers modified with alkoxysilane groups according to one of claims 1 to 5, characterized in that a mixture of isocyanate-reactive compounds A, in which isocyanate-reactive groups are present according to definition A, is first reacted with a deficiency of polyisocyanate B to give a prepolymer containing isocyanate-reactive hydrogens, which is subsequently masked by reaction with isocyanate-functional alkoxysilane compounds, component C.

7. Process according to claim 6, characterized in that NCO/Y is used₁-an insufficient amount of polyisocyanate with a H ratio of 1.0: 1.3 to 1.0: 3.0 for the synthesis of the prepolymer comprising isocyanate-reactive hydrogens.

8. Process according to claim 6, characterized in that NCO/Y is used₁-a deficit of polyisocyanate having a H ratio of 1.0: 1.5 to 1.0: 2.0 is used for containing isocyanateSynthesis of reactive hydrogen prepolymer.

9. Process according to claim 6, characterized in that the prepolymer comprising isocyanate-reactive hydrogens is reacted with an isocyanate-functional alkoxysilane compound with an NCO/Y of 0.8: 1.0 to 1.5: 1.0₁-H ratio.

10. Use of polymers modified with alkoxysilane groups according to one of claims 1 to 5 in adhesives, coatings and foams.

11. An adhesive and coating formulation comprising:

from 10% by weight to 100% by weight of a polymer modified with alkoxysilane groups according to any one of claims 1 to 5, or of a mixture of two or more of these polymers modified with alkoxysilane groups,

0% to 30% by weight of a plasticizer or a mixture of two or more plasticizers,

0% to 30% by weight of a solvent or a mixture of two or more solvents,

0% to 5% by weight of a wet stabilizer or a mixture of two or more wet stabilizers,

0% to 5% by weight of a UV stabilizer or a mixture of two or more UV stabilizers,

0% to 5% by weight of a catalyst or a mixture of two or more catalysts,

0% to 80% by weight of a filler or a mixture of two or more fillers,

wherein the sum of the fractions of the components is 100% by weight.