DE102011088170A1 - Reactive pressure-sensitive adhesives - Google Patents

Abstract

The present invention relates to the use of special alkoxysilane and OH-terminated polyurethane prepolymers as reactive pressure-sensitive adhesives or as a component of reactive pressure-sensitive adhesives.

Description

The present invention relates to the use of special alkoxysilane and OH-terminated polyurethane prepolymers as reactive pressure-sensitive adhesives or as a component of reactive pressure-sensitive adhesives.

Pressure-sensitive adhesives have been known for a long time. Due to their positive environmental impact, bonding with these adhesives has become an integral part of modern manufacturing processes. Suitable pressure-sensitive adhesives have a permanent tackiness, a good wetting behavior for various surfaces and a balanced degree of adhesion and cohesion.

Standard pressure-sensitive adhesives are not chemically reactive. They do not change during the bonding process and in the application. They have a permanent surface tackiness, which allows bonding by means of contact pressure, but without the supply of energy. The long-term adhesive properties of a pressure-sensitive adhesive bond are essentially determined by the viscoelastic and plastic deformation behavior under load, which is a decisive disadvantage of standard pressure-sensitive adhesives: under static tensile shear stress these adhesives tend to creep, resulting in reduced tensile strength, in extreme cases leads to release the adhesive bond. Therefore, reactive adhesives are increasingly being developed in recent times, which crosslink after application by chemical reactions to form covalent bonds. As a result, the maximum operating temperature increases, the solvent resistance is improved and the creep under static Zugscherbelastung is significantly improved.

Reactive acrylate-based pressure sensitive adhesives are exemplified in U.S. Pat US Pat. No. 4,737,559 described. The pressure-sensitive adhesives described there are crosslinkable by UV radiation and represent a substantial improvement over the standard pressure-sensitive adhesives. However, a problem with these UV-crosslinkable pressure-sensitive adhesives is the fact that the complex UV technology fails with complicated geometries of the workpieces to be bonded.

More suitable as reactive pressure-sensitive adhesives are alkoxysilane-functional polymers. Alkoxysilane-functional polyacrylate polymers are exemplified in the US-A 4,112,213 or the WO 2004/011568 described. The alkoxysilane-functional polyacrylate polymers described there have, in principle, no defined 'silane functionality' but a statistical distribution of alkoxysilane groups within the polymer chains. Therefore, the reproducible adjustment of the adhesive properties in reactive pressure-sensitive adhesives based on alkoxysilane-functional polyacrylate polymers is problematic.

With regard to the reproducible adjustment of the adhesive properties, alkoxysilane-functional polyester polymers are more suitable, as exemplified in US Pat WO 2008/027496 to be discribed. When bonding with binders based on polyesters but there is basically the problem of ester hydrolysis by hydrolysis, which is why such adhesives often fail under permanent moisture load.

In the EP-A 2 104 695 and the EP-A 1 874 840 is logically described the use of unsaponifiable alkoxysilane-functional polybutadiene polymers for the preparation of reactive pressure-sensitive adhesives. The problem with these binders, however, is the fact that the polybutadiene polyols used as raw materials are expensive and difficult to obtain and have a technical disadvantage of a fluctuating OH functionality, which is why it is difficult in this case to set a defined silane functionality in the polymer molecules. Consequently, the reproducible adjustment of the adhesive properties is difficult even with these binders.

A well-defined OH functionality possess hydroxy-functional polyether polyols, in particular polyether polyols with a low degree of unsaturation, as exemplified in the EP-A 0 283 148 and the US-A 3,278,457 to be discribed.

Alkoxysilane-functional polyurethane polymers based on polyether polyols are therefore of particular interest as binders for reactive pressure-sensitive adhesives. Corresponding products are exemplified in the EP-A 1 715 015 . EP-A 0 336 431 . WO 2006/134995 and the WO 2009/106699 described.

In order to use these polymers as reactive pressure-sensitive adhesives, the addition of tackifying resins may be required, which is explicitly described in all publications mentioned. These resins are needed to enhance tack, but are not attached to the binder. They can therefore migrate from the adhesive film to the interface of the substrate and remain so after detachment of the adhesive tape on the substrate. This non-residue-free release interferes with many applications, especially when polymethyl methacrylate (PMMA) was used as a substrate. For high-gloss, decorative PMMA surfaces, the removal of adhesive residues very often leads to scratching of the surface or, if the adhesive residues have been removed with the help of organic solvents, to a matt surface.

The utility of alkoxysilane and OH-functional polyurethane prepolymers as pressure-sensitive adhesive or as part of pressure-sensitive adhesives is within the teaching of DE-A 3 220 865 basically suggested. In this application, alkoxysilane and OH-functional polyurethane prepolymers with polyester, polyether, poly (meth) acrylate or polybutadiene structure are generally described as binders for pressure-sensitive adhesives. However, it is explicitly mentioned and shown in the examples that the polyether-based prepolymers according to the invention show no inherent adhesion.

It is an object of the present invention to provide reactive pressure-sensitive adhesives based on alkoxysilane-functional polyethers which are also suitable for the production of reactive pressure-sensitive adhesives without the addition of tackifying resins and show good adhesion, in particular to PMMA.

• A) Isocyanatfunktionellen Polyurethan-Prepolymeren, hergestellt durch unvollständige, bei einem Umsatz von 50 bis 90 Gew.-% der OH-Gruppen der Polyolkomponente gestoppte Umsetzung von i) einer aromatischen, aliphatischen oder cycloaliphatischen Diisocyanatkomponente mit einem NCO-Gehalt von 20 bis 60 Gew.-% mit ii) einer Polyolkomponente, die als Hauptkomponente ein Polyoxyalkylendiol umfasst, das ein Molekulargewicht von 3000 bis 30000 aufweist, mit
• B) Alkoxysilan- und Aminogruppen aufweisenden Verbindungen der Formel (I)
  
  in welcher X, Y, Z für gleiche oder verschiedene gegebenenfalls verzweigte C₁-C₈-Alkyl- oder C₁-C₈-Alkoxyreste stehen, mit der Maßgabe, dass mindestens einer der Reste für eine C₁-C₈-Alkoxygruppe steht, R für gegebenenfalls verzweigte Alkylenradikale mit 1 bis 8 Kohlenstoffatomen steht, R' für Wasserstoff, gegebenenfalls verzweigte C1-C8-Alkylreste, C6-C10-Arylreste oder Reste der allgemeinen Formel (II) steht
  
  wobei R'' und R''' gleiche oder verschiedene, gegebenenfalls verzweigte Alkylreste mit 1 bis 8 Kohlenstoffatomen bedeuten

als Bestandteil von reaktiven Haftklebstoffen.The invention relates to the use of alkoxysilane and OH-terminated polyurethane prepolymers obtained by reacting

• A) isocyanate-functional polyurethane prepolymers prepared by incomplete, stopped at a conversion of 50 to 90 wt .-% of the OH groups of the polyol component of i) an aromatic, aliphatic or cycloaliphatic diisocyanate having an NCO content of 20 to 60 wt .-% with ii) a polyol component comprising as a main component a polyoxyalkylene diol having a molecular weight of 3000 to 30,000, with
• B) compounds of the formula (I) having alkoxysilane and amino groups
  
  in which X, Y, Z are identical or different, optionally branched C ₁ -C ₈ -alkyl or C ₁ -C ₈ -alkoxy radicals, with the proviso that at least one of the radicals is a C ₁ -C ₈ -alkoxy group , R is optionally branched alkylene radicals having 1 to 8 carbon atoms, R 'is hydrogen, optionally branched C 1 -C 8 -alkyl radicals, C 6 -C 10 -aryl radicals or radicals of the general formula (II)
  
  where R "and R"'are identical or different, optionally branched alkyl radicals having 1 to 8 carbon atoms

as a component of reactive pressure-sensitive adhesives.

The invention is based on the surprising observation that the alkoxysilane and OH-functional polyether-polyurethane prepolymers to be used according to the invention themselves have a sufficient inherent tack, adhere perfectly to PMMA and can be removed without residue.

The alkoxysilane and OH-functional polyether polyurethane prepolymers to be used according to the invention as pressure-sensitive adhesives or as constituents of pressure-sensitive adhesives are known in principle and are described in US Pat EP-A 1 474 460 , According to the teaching of this publication, these prepolymers can be used in special formulations as highly elastic building sealants. The possible use as an adhesive is mentioned, but not a use for the production of reactive pressure-sensitive adhesives. The Usability of the prepolymers described in EP-A 1 474 460 as a constituent of pressure-sensitive adhesives, which can be formulated especially without the addition of tackifying resins, is by no means obvious since this publication explicitly points to the low surface tack of the sealants produced with these polymers.

The Isocyanatprepolymere A) to be used according to the invention are used in accordance with the teaching of EP-A 1 474 460 by reacting a diisocyanate component i) with a polyol component ii) characterized in more detail below.

As polyisocyanate component i) isocyanates which can be used according to the invention are any aliphatic, cycloaliphatic or aromatic diisocyanates of the prior art with an isocyanate content of from 20 to 60% by weight. As component i) or part of component i) are preferably suitable aromatic or cycloaliphatic diisocyanates of molecular weight range 174 to 300 g / mol such as 4,4'-diphenylmethane diisocyanate, optionally in admixture with 2,4'-diphenylmethane diisocyanate, 2,4-diisocyanatotoluene its technical mixtures with preferably up to 35 wt .-%, based on the mixture, of 2,6-diisocyanatotoluene, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), bis (4-isocyanatocyclohexyl ) methane, 1-isocyanato-1-methyl-4 (3) -isocyanatomethyl-cyclohexane, 1,3-diisocyanato-6-methyl-cyclohexane, optionally in admixture with 1,3-diisocyanato-2-methylcyclohexane. Of course, mixtures of said isocyanates can be used.

Particularly preferred components i) are 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate and the mixtures of these isomeric diisocyanates or 2,4-diphenylmethane diisocyanate. Diisocyanatotoluol, 2,6-diisocyanatotoluene and the mixtures of these isomeric diisocyanates used.

The preparation of the polyurethane prepolymers A) is carried out according to the teaching of EP-A 1 474 460. In this case, the diisocyanate component i) is reacted with a polyol component ii) such that 10 to 50% by weight of the OH groups of the polyol component ii) are not reacted with the NCO groups of the diisocyanate component i), so that the polyurethane prepolymer produced A) 50 to 90 wt .-% of the OH groups of the polyol component ii) are reacted.

The polyol component ii) consists essentially of at least one polyoxyalkylene diol having a molecular weight of 3000 to 30 000 g / mol (corresponding to an OH number of 37.3 to 3.7), preferably 4000 to 25000 g / mol (corresponding to an OH number). Number from 28 to 5.1). The polyoxyalkylene diols which can preferably be used according to the invention can be prepared in a manner known per se from polyurethane chemistry by ethoxylation and / or propoxylation of suitable starter molecules. Suitable starter molecules are any diols such as ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 2-ethylhexanediol-1,3 or primary monoamines such as aliphatic amines such as ethylamine or butylamine. Preference for use polyoxyalkylenediols have a mean, calculated from OH content and functionality molecular weight of 3000 to 30000 g / mol, preferably 4000 to 25000 g / mol and an ethylene oxide content of at most 40 wt .-%, based on the total weight of the polyoxyalkylene.

Very particular preference is given to using, as component ii), polypropylene oxide polyethers having a terminal unsaturation of not more than 0.04 meq / g and a mean molecular weight of 8,000 to 22,000 g / mol calculated from OH content and functionality.

The polyether polyols having a low degree of unsaturation which can be used particularly preferably according to the invention are known in principle and are described by way of example in US Pat EP-A 2 83 148 and the US-A 3,278,457 described.

In the preparation of the NCO prepolymers A) optionally minor amounts of low molecular weight 2 and 3-valent alcohols of molecular weight 32 to 500 g / mol can be used.

In the preparation of the NCO prepolymers A) can continue to be used minor amounts of polyfunctional polyether polyols of the prior art.

The polyurethane prepolymers which can be used according to the invention as component A) are prepared by reacting the diisocyanate component (i) with the diol component (ii) in the temperature range from 40 to 120 ° C., preferably from 50 to 100 ° C. while maintaining an NCO / OH equivalent ratio of 1.1: 1 to 2.0: 1, preferably 1.1: 1 to 1.6: 1. The reaction is stopped as soon as a reaction of 50-95% by weight of the OH groups of the polyol component, preferably 70-95% by weight of the OH groups of the polyol component, has been reached, ie the polyol component still contains 5 to 50% by weight. -%, preferably 5 to 30 wt .-% of free, not reacted with NCO groups OH groups. The conversion is determined by an NCO titrimetric method customary in polyurethane chemistry. The reaction is stopped by the addition of a small amount of a mineral or organic acid such as hydrochloric acid, sulfuric acid, phosphoric acid or its derivatives, formic acid, acetic acid or other alkane or organic acid or an acid releasing component such as acid halides or acid anhydrides. By way of example, mention may be made here of formic acid chloride, acetic acid chloride, propionic acid chloride and benzoyl chloride. According to the invention, the use of benzoyl chloride as stopper is preferred.

Optionally, the use of the stopper can be dispensed with and the aminosilane compound can be added directly. It is necessary to proceed quickly in order to prevent the further progress of the isocyanate-OH reaction to the detriment of the isocyanate-NH reaction as far as possible.

Optionally, in the preparation of the polyurethane prepolymers known from polyurethane chemistry per se amine or organometallic catalysts can be used.

The inventively employable polyurethane prepolymers A) have an NCO content of 0.1 to 2.0 wt .-%, preferably 0.1 to 1.0 wt .-%. Depending on the ratio of NCO to OH groups, this corresponds to an average molecular weight of 4200 to 84000 g / mol, preferably 8400 to 84000 g / mol, calculated from the NCO content and functionality.

in welcher
X, Y, Z für gleiche oder verschiedene, gegebenenfalls verzweigte C₁-C₈-Alkyl- oder C₁-C₈-Alkoxyreste stehen, mit der Maßgabe, dass mindestens einer der Reste für eine C₁-C₈-Alkoxygruppe steht,
R für gegebenenfalls verzweigte Alkylenradikale mit 1 bis 8 Kohlenstoffatomen, vorzugsweise 1 bis 4 Kohlenstoffatomen stehen,
R' für Wasserstoff, gegebenenfalls verzweigte C1-C8-Alkylreste, C6-C10-Arylreste oder Reste der allgemeinen Formel (II) steht

wobei
R'' und R''' für gleiche oder verschiedene, gegebenenfalls verzweigte Alkylreste mit 1 bis 8 Kohlenstoffatomen, vorzugsweise 1 bis 4 Kohlenstoffatomen stehen.The inventively employable polyurethane prepolymers A) are reacted in the second stage of the process according to the invention with compounds of the formula (I)

in which
X, Y, Z are identical or different, optionally branched C ₁ -C ₈ -alkyl or C ₁ -C ₈ -alkoxy radicals, with the proviso that at least one of the radicals is a C ₁ -C ₈ -alkoxy group,
R is optionally branched alkylene radicals having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms,
R 'is hydrogen, optionally branched C 1 -C 8 -alkyl radicals, C 6 -C 10 -aryl radicals or radicals of the general formula (II)

in which
R '' and R '''are identical or different, optionally branched alkyl radicals having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms.

Preference is given to using an alkoxysilane- and amino-containing compounds having the general formula (I) whose radical R 'corresponds to the general formula (II). The preparation of such a compound is in the EP-A 0 596 360 described.

The reaction of the NCO prepolymers with the compounds of the formula (I) having alkoxysilane and amino groups in the process according to the invention takes place within a temperature range from 0 to 150.degree. C., preferably from 20 to 80.degree. C., the proportions generally being chosen such that that 0.95 to 1.1 mol of aminosilane compound are used per mole of NCO groups used. Preferably, 1 mole of aminosilane compound is used per mole of NCO groups used. When using higher reaction temperatures, it may according to the teaching of EP-A 0 807 649 come to a cyclocondensation reaction, which is by no means disturbing and sometimes even beneficial.

The polyurethane prepolymers containing alkoxysilane and OH groups which are used as pressure-sensitive adhesives or as constituents of pressure-sensitive adhesives are viscous products which are liquid at room temperature. To prepare the adhesives, crosslinking catalysts are added to the prepolymers to be used according to the invention. Furthermore, the usual additives for pressure sensitive adhesives may be added to the adhesives, such as fillers, solvents, desiccants, adhesion promoters, plasticizers, polymer stabilizers and, although not required according to the invention, tackifying resins.

In principle, all catalysts which accelerate the silane polycondensation are suitable as crosslinking catalysts. Specific examples of suitable catalysts are titanates (e.g., tetrabutyl titanate, tetrapropyl titanate, etc.); Tin carbonate salts (e.g., dibutyltin dilaurate, dibutyltin maleate, dibutyltin diacetate, tin octylates, tin naphthenates, etc.); organic zirconium compounds (e.g., zirconium tetraisopropoxide, zirconium tetrabutoxides, etc.); Reaction products of dibutyltin oxide with phthalates; Chelating agents such as organic aluminum compounds (e.g., aluminum trisacetylacetonates, aluminum trisethylacetoacetonates, diisopropoxyaluminum ethylacetoacetonates, etc.), dibutyltin diacetylacetonates, zirconium tetraacetylacetonates, titanium tetraacetylacetonates, and the like; Amines (e.g., butylamine, monoethanolamine, triethylenetriamine, guanidine, 2-ethyl-4-methylimidazole, diazabicyclo 1.8 [5.4.0] undecene-7 (DBU), etc.) or their salts with carboxylic acids. Aminic curing catalysts are particularly preferably used. Of course, mixtures of the catalysts mentioned can be used. The crosslinking catalysts are used in amounts of from 0.01 to 1% by weight, preferably from 0.05 to 0.5% by weight, based on the amount of the prepolymer.

As polymer stabilizers, it is possible to use all polymer stabilizers known for stabilizing polyetherurethanes. By way of example, antioxidants such as sterically hindered phenols, phosphites, phosphonites, benzophenone- or triazole-type UV absorbers and UV stabilizers based on sterically hindered amines may be mentioned at this point. Particularly advantageous are mixtures of said stabilizers. Stabilization with the aid of antioxidants and UV protectors based on sterically hindered amines is particularly preferred.

Silica acids, calcium carbonate, talc, titanium oxide, zinc oxide, silica and barium sulfate may be mentioned as examples of suitable fillers. Of course, surface-treated fillers or mixtures of fillers may also be used. According to the invention, only small amounts of fillers corresponding to a mass fraction <10% are used to prepare the pressure-sensitive adhesives. It is essential that the fillers to be used have a low moisture content, so that the storage stability of the adhesive formulation is not adversely affected.

With regard to a good surface wetting and for adjusting the application viscosity, the use of organic solvents may be advantageous. It is possible to use the solvents customary in adhesive technology, whereby attention must also be paid here to a low water content. Examples of suitable solvents are: ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methoxypropyl acetate, ethylene glycol monoethyl ether acetate, toluene, xylene, white spirit or any mixtures of these solvents.

As desiccants for improving the storage stability of the adhesive formulations, alkoxysilyl compounds may be added. Examples of suitable drying agents are vinyltrimethoxysilane, methyltrimethoxysilane, i-butyltrimethoxysilane, hexadecyltrimethoxysilane. Such desiccants only have to be used if formulation components which can contain moisture are used.

Furthermore, the pressure-sensitive adhesives adhesion promoter can be added to achieve good adhesion to problematic substrates. Suitable adhesion promoters are the known functional silanes such as aminosilanes of the type mentioned above but also N-aminoethyl-3-aminopropyl-trimethoxy and / or N-aminoethyl-3-aminopropyl-methyl-dimethoxysilane, epoxy silanes and / or mercaptosilanes. However, the co-use of the adhesion promoter can hinder the residue-free removal of adhesive residues and is therefore less preferred.

Furthermore, the pressure-sensitive adhesives according to the invention may contain plasticizers. Examples of suitable plasticizers are the known phthalic acid esters, phosphoric esters, sulfonic esters and propylene glycols. Pressure-sensitive adhesives containing no plasticizers are preferred.

The pressure-sensitive adhesives according to the invention can furthermore also comprise tackifying resins, although their use is by no means preferred, since the presence of such resins prevents residue-free removal and is counterproductive for the purposes of the invention. Examples of tackifying resins Phenolic resins, modified phenolic resins (eg, cashew oil-modified phenolic resins, tall oil-modified phenolic resins, etc.), terpene-phenolic resins, xylene-phenolic resins, cyclopentadiene-phenolic resins, xylene resins, petroleum resins, phenol-modified petroleum resins, low molecular weight polystyrene resins or terpene resins ,

The pressure-sensitive adhesives according to the invention preferably contain only crosslinking catalysts and polymer stabilizers in addition to the alkoxysilane and OH-containing polyurethane prepolymers. The adhesives show excellent adhesion to metallic substrates as well as to various plastics with exceptionally low creep under static tensile shear stress. Pressure-sensitive adhesives, which contain only crosslinking catalysts and polymer stabilizers, can be easily removed from the substrate without any residue, eliminating the need for time-consuming removal of adhesive residues. Especially good is the adhesion to PMMA. With this property profile, the pressure-sensitive adhesives according to the invention are outstandingly suitable for the production of coated substrates such as, for example, adhesive tapes, adhesive films and adhesive labels, of which at least part of the surface is coated with a layer of pressure-sensitive adhesive according to the invention. Against this background, such coated substrates or articles, preferably adhesive tapes, adhesive films and adhesive labels also subject of the present invention.

The following examples are intended to illustrate the essence of the invention without limiting it.

Examples

All percentages are by weight (% by weight), unless otherwise indicated.

The ambient temperature of 23 ° C prevailing at the time of the experiment is referred to as RT (room temperature).

The methods listed below for determining the corresponding parameters were used for carrying out or evaluating the examples and are also the methods for determining the parameters relevant to the invention in general.

Determination of viscosity

The viscosity measurements were according to ISO / DIN 3219: 1990 at a constant temperature of 23 ° C. and a constant shear rate of 250 / sec with a plate-cone Physica MCR rotational viscometer (Anton Paar Germany GmbH, Ostfildern, DE) using the measuring cone CP 25-1 (25 mm diameter, 1 ° cone angle).

Determination of the isocyanate content

The determination of the NCO contents in wt .-% was according to DIN EN ISO 11909 by back titration with 0.1 mol / l hydrochloric acid after reaction with butylamine.

example 1

971 g of a polypropylene glycol having an OH number of 6.2 (Acclaim 18200 ^®, Bayer MaterialScience AG, Leverkusen) for six hours in a vacuum (low nitrogen flow) dehydrated at 120 ° C. Then with 14.8 g of isophorone diisocyanate (Bayer MaterialScience AG, Leverkusen) (ratio 1.3) at 60 ° C with the addition of 40 ppm dibutyltin dilaurate (Desmorapid ^® Z, Bayer MaterialScience AG, Leverkusen) until reaching an NCO content of 0.17% (= 90% conversion) prepolymerized. The reaction is stopped by adding 50 ppm of benzoyl chloride (Fluka Chemie GmbH, Buchs, Switzerland). Subsequently, at 60 ° C 14.4 g of N- (3-trimethoxysilylpropyl) aspartic acid diethyl ester (prepared according to EP-A 0 596 360 , Ex. 5) is added dropwise rapidly and the mixture is stirred until no isocyanate band can be seen in the IR spectrum. The resulting alkoxysilyl- and OH-terminated polyurethane prepolymer is diluted to a solids content of 52% by weight with methoxypropyl acetate to determine the viscosity and to determine the adhesive properties. The viscosity of the solution is 4500 mPas (23 ° C).

Example 2

969 g of a polypropylene glycol having an OH number of 6.2 (Acclaim ^® 18200) for six hours dehydrated in vacuum (low nitrogen flow) at 120 ° C. After addition of 3.2 ppm dibutyltin dilaurate and 1 L methoxypropyl acetate with 16.6 g of 2,4'-diphenylmethane diisocyanate (Bayer MaterialScience AG, Leverkusen) at 60 ° C until reaching an NCO content of 0.20% (= 85 % Conversion) prepolymerized. The reaction is stopped by adding 4 ppm of dibutyl phosphate (Fluka Chemie GmbH, Buchs, Switzerland). Then, at 60 ° C., 16.9 g of N- (3-trimethoxysilylpropyl) aspartic acid diethyl ester (prepared in accordance with EP-A 0 596 360 , Ex. 5) is added dropwise rapidly and the mixture is stirred until no isocyanate band can be seen in the IR spectrum. The viscosity of the solution is 12100 mPas (23 ° C).

Example 3:

969 g of a polypropylene glycol having an OH number of 6.2 (Acclaim ^® 18200) for six hours dehydrated in vacuum (low nitrogen flow) at 120 ° C. After addition of 3.2 ppm of dibutyltin dilaurate and 1 L of methoxypropyl acetate with 16.6 g of 2,4'-diphenylmethane diisocyanate (Bayer MaterialScience AG, Leverkusen) at 60 ° C until reaching an NCO content of 0.17% (= 90 % Conversion) prepolymerized. The reaction is stopped by adding 4 ppm of dibutyl phosphate (Fluka Chemie GmbH, Buchs, Switzerland). Subsequently, at 60 ° C 14.4 g of N- (3-trimethoxysilylpropyl) aspartic acid diethyl ester (prepared according to EP-A 0 596 360 , Ex. 5) is added dropwise rapidly and the mixture is stirred until no isocyanate band can be seen in the IR spectrum. The viscosity of the solution is 16500 mPas (23 ° C).

Carrying out the 90 ° peel test:

The resulting polymers are mixed with the amounts of catalyst mentioned in Table 1 and homogenized. example Catalyst / Quantity 1 and 2 Metatin K 740 / 0.13% 3 Metatin K 740 / 0.02%

To determine the adhesive properties, a 100 μm (wet) thick film of the polymer was applied to a film using a doctor blade. Subsequently, the polymer-coated film was stored for 7 days at 23 ° C and 50% relative humidity, cut into 1.5 cm wide and 12 cm long strips and added with 2 kg contact pressure (roller) on the substrate. After 1 and 7 days, the 90 ° peel test (speed: 300 mm / min at a 90 ° angle, measuring section (Lm): 7 cm) was carried out. 90 ° peel test Measurement after joining KTL stole Alu PMMA PVC SECTION Glass Example 1 [N / cm] 1 day 3.24 2.18 2.94 3.77 2.56 2.90 3.27 Example 1 [N / cm] 7 days 4.25 3.34 3.68 4.54 3.01 3.23 4.12 Ex.2 [N / cm] 1 day 3.44 2.71 2.65 6.45 2.91 4.46 3.36 Ex.2 [N / cm] 7 days 4.72 3.11 3.24 8.57 3.56 5.23 4.74 Example 3 [N / cm] 1 day 4.77 2.65 2.77 6.64 2.80 4.50 3.30 Example 3 [N / cm] 7 days 5.43 3.09 3.21 8.82 3.68 5.02 4.98

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 4737559 [0004]
• US 4112213 A [0005]
• WO 2004/011568 [0005]
• WO 2008/027496 [0006]
• EP 2104695 A [0007]
• EP 1874840 A [0007]
• EP 0283148 A [0008]
• US 3278457 A [0008, 0022]
• EP 1715015 A [0009]
• EP 0336431A [0009]
• WO 2006/134995 [0009]
• WO 2009/106699 [0009]
• DE 3220865 A [0011]
• EP 1474460A [0015, 0016, 0019]
• EP 283148A [0022]
• EP 0596360A [0030, 0048, 0049, 0050]
• EP 0807649 A [0031]

Cited non-patent literature

• ISO / DIN 3219: 1990 [0046]
• DIN EN ISO 11909 [0047]

Claims (10)

Use of alkoxysilane and OH-terminated polyurethane prepolymers obtained by reaction of A) isocyanate-functional polyurethane prepolymers prepared by incomplete, stopped at a conversion of 50 to 95 wt .-% of the OH groups of the polyol component reaction of ii) an aromatic, aliphatic or cycloaliphatic diisocyanate component having an NCO content of 20 to 60% by weight with ii) a polyol component comprising as main component a polyoxyalkylene diol having a molecular weight of 3,000 to 30,000 g / mol, with B) alkoxysilane and amino-containing compounds of the formula (I)

in which X, Y, Z are identical or different, optionally branched C ₁ -C ₈ -alkyl or C ₁ -C ₈ -alkoxy radicals, with the proviso that at least one of the radicals is a C ₁ -C ₈ -alkoxy group , R is optionally branched alkylene radicals having 1 to 8 carbon atoms, R 'is hydrogen, C ₁ -C ₈ -alkyl radicals, C ₆ -C ₁₀ -aryl radicals or radicals of the general formula (II)

where R "and R"'denote identical or different, optionally branched alkyl radicals having 1 to 8 carbon atoms as constituent of reactive pressure-sensitive adhesives. Use of polyurethane prepolymers according to claim 1, characterized in that the polyurethane component A) by incomplete, stopped at a conversion of 70-95% of the OH groups of the polyol component reaction of i) and ii) is prepared. Use of polyurethane prepolymers according to claim 1 and 2, characterized in that for the preparation of the polyurethane prepolymers A) polypropylene oxide polyether having a terminal unsaturation of not more than 0.04 meq / g and a mean, calculated from OH content and functionality molecular weight of 8,000 be used up to 22000 g / mol. Use of polyurethane prepolymers according to Claims 1 to 3, characterized in that the radical R 'is a radical of the general formula (II) in which X, Y and Z independently of one another are methoxy or ethoxy. Reactive pressure-sensitive adhesives containing alkoxysilane and OH-terminated polyurethane prepolymers which are prepared by reacting A) isocyanate-functional polyurethane prepolymers prepared by incomplete, stopped at a conversion of 50 to 95 wt .-% of the OH groups of the polyol component reaction of iii) an aromatic, aliphatic or cycloaliphatic diisocyanate component having an NCO content of 20 to 60% by weight with ii) a polyol component comprising as main component a polyoxyalkylene diol having a molecular weight of 3,000 to 30,000 g / mol, with B) Alkoxysilane- and amino-containing compounds of the formula (I)

in which X, Y, Z are identical or different, optionally branched C ₁ -C ₈ -alkyl or C ₁ -C ₈ -alkoxy radicals, with the proviso that at least one of the radicals is a C ₁ -C ₈ -alkoxy group , R is optionally branched alkylene radicals having 1 to 8 carbon atoms, R 'is hydrogen, C ₁ -C ₈ -alkyl radicals, C ₆ -C ₁₀ -aryl radicals or radicals of the general formula (II)

where R "and R"'are identical or different, optionally branched alkyl radicals having 1 to 8 carbon atoms. Reactive pressure-sensitive adhesives according to claim 5, characterized in that they additionally contain crosslinking catalysts, polymer stabilizers and fillers, solvents, drying agents, adhesion promoters, plasticizers and tackifying resins. Reactive pressure-sensitive adhesives according to claim 5, characterized in that they contain in addition to the alkoxysilane and OH-terminated polyurethane prepolymers crosslinking catalysts and polymer stabilizers. Use of the reactive pressure-sensitive adhesives according to Claims 5 to 7 for the production of self-adhesive articles. Use of the reactive pressure-sensitive adhesives according to Claims 5 to 7 for the production of adhesive tapes, adhesive films or adhesive labels. Adhesive tapes, adhesive films and adhesive labels comprising at least one layer of a reactive pressure-sensitive adhesive according to claims 5 to 7.