EP2283076A1

EP2283076A1 - Sealing mass that can be cross-linked using water

Info

Publication number: EP2283076A1
Application number: EP09761562A
Authority: EP
Inventors: Lars Zander; Jens LÜCKERT; Martin Majolo; Andreas Bolte; Johann Klein; Thomas Bachon; Sven Balk; Holger Kautz; Stephan Fengler
Original assignee: Henkel AG and Co KGaA; Evonik Roehm GmbH
Current assignee: Henkel AG and Co KGaA; Roehm GmbH Darmstadt
Priority date: 2008-05-28
Filing date: 2009-05-08
Publication date: 2011-02-16
Also published as: WO2009149999A1; CN102046725A; JP2011525201A; US20110166285A1; CN102046725B; DE102008025575A1

Abstract

The invention relates to a cross-linkable composition containing 10-50 % by weight of silane-group terminated polymers with a number average molecular weight of between 3,000 and 30,000 g/ mol, 0.5 to 20 % by weight of (meth)acrylate block copolymers of type A(BA)n, where n = 1 to 5 and said copolymers contain at least two hydrolysable silane groups, 85 to 40% by weight of fillers and auxiliary agents, the sum of the constituents totalling 100%. The invention is characterised in that the (meth)acrylate block copolymers have a number average molecular weight of between 5,000 and 100,000 g/mol and that the silane groups are contained in at least one block A or B and said groups are not terminal in the polymer chain.

Description

Water-crosslinkable sealant

The invention relates to compositions based on mixtures of silane-terminated polyethers and block copolymers based on (meth) acrylate monomers which contain hydrolyzable silane groups in at least one block.

Compositions based on silane-terminated polyethers are known. Such compositions can be used as a sealant, adhesive or the like. EP-A 0673972 describes curable compositions containing an oxyalkylene polymer containing at least one reactive silicon radical per molecule. Furthermore, the compositions should contain copolymers based on alkyl (methacrylates), which are copolymers of alkyl acrylates having an alkyl radical having up to 8 carbon atoms and alkyl acrylates having an alkyl radical having more than 9 carbon atoms. Optionally, the methacrylate copolymers may have functional groups, such as epoxy groups, amino groups or even silane groups. No statement is made about a particular structure of the (meth) acrylate copolymers.

It is known EP-A 0918062. This describes a crosslinkable mixture of a silicone polymer containing hydrolyzable silane groups and a (meth) acrylate copolymer which also contains hydrolyzable silane groups. As initiators for the preparation of the acrylate copolymers, the known free-radically splitting initiators are described. Block copolymers are not described and can not be prepared with the stated initiators. Furthermore, EP-A 1396513 is known. In this polyoxyalkylene polymers are described which contain hydrolyzable silane groups. In these compositions, additional copolymers of polymerizable unsaturated monomers may be included, for example, styrene or Acrylate. These may optionally also contain hydrolyzable silane groups, which may be copolymerized in, for example, by vinylalkoxysilanes. These are conventional random acrylate copolymers.

Furthermore, EP-A 1000980 is known. In this are described curable compositions containing a polyether polymer or an epoxy resin having at least one crosslinkable silyl group and a vinyl polymer having at least one crosslinkable silyl group, wherein the polydispersity of this vinyl polymer is less than 1, 8. The functionalized vinyl polymers are obtained by reacting vinyl polymers which still contain unsaturated double bonds by reaction at this double bond with silane derivatives. Another method described is the nucleophilic substitution of einpolymersierten halocarbon bonds by compounds which have nucleophilic groups and crosslinkable silane groups in addition. The described embodiments have in particular a silane group at the chain end.

Furthermore, EP-A 1036807 is known. In this polyoxyalkylene polymers are described which are substituted at least 85% at the chain ends with silane groups. Thus, in the described diols, there are at most or less than 2 silane groups in the chain. A combination of such polymers with special acrylate copolymers is not described.

Acrylate polymers having only one reactive silane group can be incorporated into a polymer matrix only as a side chain. In particular, when the silane group is terminal, the acrylate chain acts as an internal plasticizer. When the reactive silane groups are polymerized into the chain, this is generally done statistically, so that different polymer forms are obtained. This means that a targeted structure structure of a crosslinking polymer is difficult to achieve. Furthermore, such polymers have the Disadvantage that due to the low proportion of crosslinking groups, a solid and elastic polymer network can not be formed. Furthermore, due to the small number of silane groups on the polymer, adhesion to various substrates is difficult to achieve. Acrylate polymers prepared by conventional free-radical polymerization have a high dispersity (measured as M _w : M _N ). As a result, the viscosity behavior is poor and the viscosity is very high.

From the various disadvantages of the known crosslinkable compositions, the object is to provide a crosslinkable 1-component polymer mixture containing as part of polyoxyalkylene polymers which crosslink via silane groups and have a sufficient number of silane groups to form an elastic network and in addition sufficient adhesion to enable to different substrates. Furthermore, it is intended to contain (meth) acrylate block copolymers which likewise have silane groups. It can be achieved by a selected structure of these copolymers that microstructures form in the crosslinked composition, which thus lead to an excellent mechanical strength of the crosslinked polymer composition. Likewise, by distributing the reactive silane groups, crosslinking can be achieved to provide high elasticity.

The object is achieved by a curable composition comprising 10 to 50% by weight of silane-terminated polymers having a number-average molecular weight of 3,000 to 30,000 g / mol, 0.5 to 20% by weight of (A) acrylate block copolymers of type A (BA) _n with n from 1 to 5, which contain at least two hydrolyzable silane groups, 85 to 40 wt .-% of fillers and auxiliaries, wherein the sum of the components should be 100%, characterized in that the (meth) acrylate block copolymers have a number average molecular weight of 5000 to 100,000 g / mol, the silane groups in contained in at least one block A or B, wherein the silane groups are not terminal to the polymer chain.

An essential component of the crosslinkable composition are polymers containing hydrolyzable functional group which can crosslink with the functional groups of the block copolymer. These are silane groups which carry 1 to 3 hydrolyzable groups on the silane radical. Up to 10 silane groups may be present on the polymer chain, but it is preferred that 2 or 3 reactive silane groups are included.

A suitable constituent of the composition according to the invention are polymers of the formula

(I) P - (R ¹ - R ² - Si R _q ³ - (OR ⁴ ) _n ) _m

where P is an organic skeleton,

R ^{1 is} an amide, carboxy, carbamate, carbonate, ureido, urethane or

Sulfonate bond, an oxygen atom, a sulfur atom or a

Methylene group means

R ^{2 is} a straight-chain or branched, substituted or unsubstituted

Alkylene radical having 1 to 8 carbon atoms,

R ^{3 is} an alkyl radical having 1 to 4 C atoms or OR ⁴ ,

R ^{4 is} an alkyl radical having 1 to 4 C atoms or an acyl radical having 1 to 4 C atoms, q = 0, 1, 2, n = 3 - q and m = 1 to 10, preferably 1 to 3 where the radicals R ³ and R ^{4 may be the} same or different.

The organic skeleton P is advantageously selected from the group comprising polyamides, polyesters, polycarbonates, polyethylenes, polybutylenes, Polystyrenes, polypropylenes, Polyoxymethylenhonno- and copolymers, polyurethanes, vinyl butyrates, vinyl polymers, ethylene copolymers, ethylene acrylate copolymers, organic rubbers and the like, or mixtures of various silylated polymers, wherein the skeleton may also contain siloxane groups in the backbone. For example, polyethers based on ethylene oxide, propylene oxide and tetrahydrofuran are also suitable. Of the polymeric backbones mentioned, polyethers and polyurethanes are preferred. Particularly preferred is polypropylene glycol.

Isocyanate-terminated PU prepolymers suitable for the composition according to the invention are known to the person skilled in the art. In US Pat. No. 4,222,925 and US Pat. No. 4,354,053, siloxane-terminated organic sealant compositions which are curable even at room temperature are disclosed, in particular isocyanate-free silane-terminated polyurethane prepolymers being described as polymers. These can be prepared on the basis of reaction products of isocyanate-terminated polyurethane prepolymers with 3-aminopropyltrimethoxysilane or 2-aminoethyl, 3-aminopropylmethoxysilane. Such PU prepolymers can be prepared by reacting diols with a stoichiometric excess of polyisocyanates. It is possible to use the known lacquer or adhesive isocyanates, generally diisocyanates.

For example, EP-A 0931800 describes the preparation of suitable silylated polyurethanes by reacting a polyol component having a terminal unsaturation of less than 0.02 meq / g with a diisocyanate to give a hydroxyl-terminated prepolymer which is then reacted with an isocyanatosilane of the formula OCN-R -Si- (X) m (-OR1) 3-m wherein m is 0.1 or 2 and each R1 radical is an alkyl group having 1 to 4 C atoms and R is a difunctional organic group. According to the teaching of this document, such silylated polyurethanes have a superior combination of mechanical properties, curing in reasonable periods of time to a little sticky sealant, without having excessive viscosity.

Other suitably functionalized PU polymers are disclosed in WO-A-2003 066701. In this case, alkoxysilane and OH-terminated polyurethane prepolymers based on high molecular weight polyurethane prepolymers with reduced functionality for use as binders for low-modulus sealants and adhesives. For this purpose, first a polyurethane prepolymer of a diisocyanate with an NCO content of 20 to 60% and a polyol component comprising a polyoxyalkylene having a molecular weight between 3000 and 20,000 g / mol as the main component, the reaction at a conversion of 50 to 90% of the OH groups to be stopped. This reaction product should then be further reacted with a compound containing alkoxysilane and amino groups. These measures are to obtain prepolymers having a relatively low average molecular weight and low viscosity, which are to ensure the achievement of a high level of properties.

For the preparation of silane-terminated prepolymers based on polyethers, the following processes have already been described:

Copolymerization of unsaturated monomers with those containing alkoxysilyl groups, e.g. Vinylthmethoxysilan.

Grafting of unsaturated monomers such as vinyltrimethoxysilane on thermoplastics such as polyethylene.

Hydroxy-functional polyethers are reacted with unsaturated chlorine compounds, for example allyl chloride, in an ether synthesis in polyethers with terminal olefinic double bonds, which in turn have hydrosilane compounds which have hydrolyzable groups, such as HSi (OCH ₃ ) ₃ in a hydrosilylation reaction under the catalytic influence For example, transition metal compounds of the 8th group can be converted to silane-terminated polyethers.

In another process, the polyethers containing olefinically unsaturated groups are reacted with a mercaptosilane, e.g. 3-Mercaptopropyl- trialkoxysilane reacted.

In another method, hydroxyl-containing polyethers are first reacted with di- or polyisocyanates, which in turn are then reacted with amino-functional silanes or mercapto-functional silanes to silane-terminated prepolymers.

Another possibility is the reaction of hydroxy-functional polyethers with isocyanato-functional silanes, e.g. 3-isocyanatopropyltrimethoxysilane.

In a preferred embodiment of the invention, such polyurethanes or in particular polyethers have a number average molecular weight (M _N, as determined by GPC) of about 5,000 to about 30,000 g / mol, in particular about 6,000 to about 25,000 g / mol. Particularly preferred are polyethers with number average molecular weights of about 10,000 to about 22,000 g / mol, in particular having molecular weights of about 12,000 to about 18,000 g / mol. Depending on the preparation method, the polyoxyalkylene polymers preferably used have a polydispersity D of not more than 1.7 or else of about 2 to 4. Particularly preferably suitable polyether polymers have a polydispersity of from about 1.01 to about 1.3 or greater.

Such polymers are commercially available under various trade names. The person skilled in the art can select them according to his wishes according to the desired reactivity or desired molecular weight.

The composition according to the invention must additionally comprise (meth) acrylate block copolymers which contain at least two hydrolyzable silane groups. These block copolymers should have the structure A (BA) _n , where n should be from 1 to 5. Such block copolymers are significantly different in their properties from known random acrylate copolymers. Corresponding (meth) acrylate copolymers and processes for their preparation are described, for example, in unpublished DE 10 2007 039 535. Furthermore, suitable functionalized (meth) acrylate polymers are described in the simultaneously filed patent application of the patent applicants under the file reference DE 10 2008 002 016.

The notation (meth) acrylate stands for the esters of (meth) acrylic acid and here means both methacrylate ester and acrylate ester. Monomers which can be polymerized both in block A and in block B are selected from the group of (meth) acrylates, for example alkyl (meth) acrylates of straight-chain, branched, cycloaliphatic or aromatic-substituted alcohols having from 1 to 40.degree Atoms or with mono or di-alcohols based on polyalkylene oxides. Such monomers and the glass transition temperatures available as copolymer are known to those skilled in the art.

In addition to the (meth) acrylates, the compositions to be polymerized may also contain further unsaturated monomers which are copolymerizable by means of ATRP. These include, for example, 1-alkenes, branched alkenes, vinyl esters, maleic acid derivatives, optionally substituted styrenes and / or heterocyclic compounds. It is possible to add to both the monomers of block A and the monomers of block B 0-50% by weight of ATRP-polymerizable monomers which are not included in the group of (meth) acrylates, or else in both block types.

The block copolymers are prepared by a sequential polymerization process. In this case, the monomer mixture for the synthesis of a block, for example A, is added to the reaction mixture only when the monomer mixture for the synthesis of the previous block, for example B, to at least 90%, preferably at least 95% has been implemented. This process ensures that blocks A or B contain less than 10%, preferably less than 5%, of the total amount of monomers of the other composition. The block boundaries are located at the respective location of the chain at which the first repeat unit of the newly added monomer mixture is located. In this case, individual blocks can also be designed as a gradient polymer in the composition.

The two block types A and B differ in their composition of the monomer mixture. In a preferred embodiment, the monomers of A and B are selected so that the blocks have as a single polymer a different T ₉ (glass transition temperature as measured by DSC). In this case, the difference of T _{9 should be} more than 5 ⁰ C, in particular more than 10 ⁰ C. In one embodiment, for example, block A is a T ₉ greater 0 ⁰ C, block B below. In another embodiment, both blocks may have a T ₉ below 0 ⁰ C.

The block copolymers which are suitable according to the invention should contain at least two hydrolyzable silane groups, the silane groups being present either in type A or type B blocks. It may also be possible that the silane groups are contained in two or more similar blocks. The silane groups should not be terminal to the polymer chain. This can be ensured by the manufacturing process. Thus, it is possible that the silane groups are randomly distributed over one polymer block, another embodiment has the silane groups near the interface between blocks A and B, another embodiment containing them close but not at the free chain end. It is preferred if in particular two blocks contain hydrolyzable silane groups. The incorporation of the silane monomers can be controlled over the time of addition to the polymerization. The functionalized monomers with silyl groups are characterized by the following general formula:

(II) H ₂ C = CR ⁷ C (O) OR ⁸ -Si (OR ⁵ ) _b R ⁶ _a Xc

In this case, the organic radicals R5 and R6 may each be identical or different from each other. Further, the organic radicals R5 and R6 are selected from the group of aliphatic hydrocarbon radicals consisting of 1 to 20 carbon atoms. These groups can be either linear, branched or cyclic. R5 can also be exclusively hydrogen. Preference is given to H, CH ₃ or C ₂ H ₅ . X is selected from the group of hydrolyzable radicals which are not alkoxy or hydroxy. This includes, but is not limited to, halo, acyloxy, amino, amido, mercapto, alkenyloxy, and like hydrolyzable groups. A, b, and c are each integers between 0 and 3, the sum being a + b + c 3 , R7 is hydrogen or an aliphatic hydrocarbon radical consisting of 1 to 20 carbon atoms. R7 is preferably hydrogen (acrylates) or a methyl group (methacrylates). The radical R8 is a divalent group. R8 is preferably divalent aliphatic hydrocarbon radicals consisting of 1 to 20 carbon atoms. Most preferably, R 8 is -CH ₂ -, - (CH ₂ ) ₂ - or - (CH ₂ ) ₃ .

A commercially available monomer is, for example, Dynasilan® MEMO from Evonik-Degussa GmbH. These are 3-methacryloxypropyltrimethoxysilane.

The polymerization can be carried out in any halogen-free solvents, but also in low-viscosity plasticizers. In particular, the ATRP method is used. This can also be carried out as emulsion, miniemulsion, microemulsion, suspension or bulk polymerization. The block copolymers are prepared by sequential polymerization. Polymerization procedures are known to those skilled in the art.

Bifunctional initiators based on halogenated esters, ketones, aldehydes or aromatic compounds are used. These are known to the person skilled in the art. Catalysts for the ATRP are described, for example, in Chem. Rev. 2001, 101, 2921. Copper complexes are predominantly described, but also iron, rhodium, platinum, ruthenium or nickel compounds are used. An alternative to the ATRP described is a variant of the same: In the so-called reverse ATRP compounds in higher oxidation states can be used.

After ATRP, the transition metal compound can be precipitated by adding a suitable sulfur compound. The sulfur compounds are preferably compounds with an SH group. Very particular preference is given to a regulator known from free-radical polymerization, such as ethylhexyl mercaptan or n-dodecylmercaptan. To increase the degree of silyl functionalization, it is also possible to use silylmercaptans, for example 3-mercaptopropyltrimethoxysilane.

Such block copolymers should have a structure ABA or BAB or higher homologues having at least 1 and a maximum of 10 silyl groups in each individual A block. Block A should represent a copolymer part containing silyl-functionalized (meth) acrylates and monomers selected from the group of (meth) acrylates and block B should be a copolymer containing one or more (meth) acrylates which have no additional silyl function, and be polymerized as ABA block copolymers. It is also possible to prepare ABA or BAB block copolymers having at least 1 and a maximum of 2 silyl groups in the individual A blocks. A preferred embodiment is block copolymers which, in an ABA structure, have at least 2 to a maximum of 4 silyl groups in the individual A blocks. Another embodiment of the invention is to provide block copolymers which are specifically functionalized only in the end segments of the polymer chain. For example, a further embodiment of the structure ABABA has a silane functionalization only in the outer A blocks.

Alternatively, it is also possible that the block A is not functionalized, but that the block B is functionalized with the silane monomers.

The block copolymers of composition ABA consist of less than 25% of the total weight, preferably less than 10% of A blocks.

The block copolymers which can be used according to the invention should have a number-average molecular weight of between 5,000 and 100,000 g / mol, in particular between 7,500 and 50,000, preferably up to 35,000 g / mol. The polydispersity can be influenced. It may be 1, 6, preferably less than 1, 4, but it is also possible to achieve particular properties to a value greater than 1, 8, in particular greater than 2 set. The polymers of the invention can be obtained as solvent-free polymers, but it is also possible that they are in solution with organic solvents or plasticizers.

The composition according to the invention may contain, in addition to the two silane-containing polymers, various additives, such as polymers, oligomers or low molecular weight components in reactive or inert form, stabilizers, catalysts, pigments and fillers or other additives. For example, reactive diluents may be included. As reactive diluents, it is possible to use all compounds which are miscible with the adhesive or sealant with reduction of the viscosity and have at least one group reactive with the binder. The reactive diluent preferably has at least one functional group which, for example, reacts after application with moisture or atmospheric oxygen. Examples of such groups are silyl groups, isocyanate groups, vinyl unsaturated groups and polyunsaturated systems. The viscosity of the reactive diluent is preferably less than 20,000 mPas, more preferably about 1 to 6,000 mPas, most preferably 10 to 1000 mPas (Brookfield RVT, 23 ⁰ C, spindle 7, 10 U / min, measured according to EN ISO 2555).

As reactive diluents it is possible to use, for example, low molecular weight substances, such as reacted with isocyanatosilanes polyalkylene glycols, Alkylthmethoxysilan, Alkylthethoxysilan, Vinylthmethoxysilan, vinyltriethoxysilane, Phenylthmethoxysilan, phenyltriethoxysilane, Octylthmethoxysilan, tetraethoxysilane, vinyldimethoxymethylsilane, vinyltriethoxysilane, Vinyltriacet- oxysilane, Isooctylthmethoxysilan, Isooctylthethoxysilan, N-dimethoxy (methyl) silyl - methyl-O-methyl-carbamate, hexadecylthmethoxysilane, 3-octanoylthio-1-propyltriethoxysilane and partial hydrolysates of these compounds.

Furthermore, it is possible to use as reactive diluents polymers which can be prepared from an organic skeleton by grafting with a vinyl silane or by reacting polyol, polyisocyanate and alkoxysilane.

The compound present as reactive diluent in the context of the present invention preferably has at least one alkoxysilyl group, in particular di- and trialkoxysilyl groups. For the preparation of inventively preferred reactive diluents, a corresponding polyol component is reacted in each case with an at least difunctional isocyanate. As at least difunctional isocyanate in the paint and Adhesive chemistry known di- or polyisocyanates or oligomers, such as tri-isocyanurates or biurets or uretdiones of particular aliphatic diisocyanates. The isocyanates are reacted in excess, then NCO-terminated prepolymers are obtained. From the isocyanate-reactive prepolymers suitable reactive diluents can be prepared by reaction with reactive silanes.

To reduce the viscosity of the composition according to the invention, it is also possible to use, in addition to or instead of a reactive diluent, solvents and / or plasticizers.

As solvents, the known paint solvents can be used. However, preference is given to using alcohols, for example C 1 -C 10 -alcohols, since here the storage stability increases.

The composition of the invention may further contain hydrophilic plasticizers. Suitable plasticizers are, for example, esters of aliphatic or aromatic carboxylic acids with linear or branched alcohols containing 1 to 12 C atoms, such as abietic acid ester, adipic acid ester, azelaic acid ester, benzoic acid ester, fatty acid ester, glycolic acid ester, phosphoric acid ester, phthalic acid ester, propionic acid ester, sebacic acid ester, sulfonic acid ester, trimellitic acid ester , or citric acid ester.

As catalysts for controlling the curing rate of the curable compositions of the invention, for example, organometallic compounds are suitable, iron or tin compounds such as tin (II) carboxylates, dialkyltin (IV) dicarboxylates Eisenacetyacetonat; Titanium, aluminum and zirconium compounds, such as alkyl titanates, organosilicon titanium compounds, titanium chelate complexes, aluminum chelate complexes, aluminum alkoxides, zirconium chelate complexes, zirconium alkoxides; bismuth carboxylates; acidic compounds, such as phosphoric acid, p-toluenesulfonic acid, boron halides, optionally as liquid complexes, aliphatic amines, diamines or polyamines. It is also possible to use mixtures of one or more catalysts from one or more of the groups just mentioned. Particularly preferred are boron trifluoride complexes, iron and titanium carboxylates or tin carboxylates. The catalyst, preferably mixtures of several catalysts, is used in an amount of 0.01 to about 5 wt .-%, in particular up to 3 wt .-%, based on the total weight of the composition.

The composition of the invention may also contain up to about 20% by weight of conventional tackifiers. Suitable as adhesion promoters are, for example, resins, terpene oligomers, coumarone / indene resins, aliphatic, petrochemical resins and modified phenolic resins. For example, copolymers of terpenes and other monomers, for example styrene, α-methylstyrene, isoprene and the like, are also counted among the terpene resins. Also suitable are the terpene-phenolic resins prepared by acid catalyzed addition of phenols to terpene or rosin. Terpene-phenolic resins are soluble in most organic solvents and oils and are miscible with other resins, waxes and rubbers. Also suitable in the context of the present invention as an additive in the above sense are the rosin resins and their derivatives, for example their esters or alcohols.

Further, the composition of the present invention may further contain up to about 5% by weight of other additives such as antioxidants or stabilizers. In particular, the known Hindered Amine Light Stabilizers (HALS) can be used. It is also possible to use UV stabilizers which carry a silyl group and are incorporated into the end product during crosslinking or curing.

It often makes sense to further stabilize the composition of the invention by drying agents against moisture penetrating to to increase the shelf-life. For example, isocyanates or silanes are suitable. It may also be the above-mentioned reactive additives based on isocyanates or hydrolyzable silanes. Examples are isocyanatosilanes, vinylsilanes, oximesilanes or tetraalkoxysilanes. The amount can be up to about 6 wt .-% dry agent.

The composition of the invention may additionally contain fillers. For example, chalk, limestone, precipitated and / or fumed silica, zeolites, bentonites, magnesium carbonate, diatomaceous earth, clay, talc, titanium oxide, iron oxide, zinc oxide, sand, quartz, flint, mica, glass powder and other ground minerals are suitable here. Furthermore, organic fillers can be used, in particular carbon black, graphite, wood fibers, wood flour, sawdust, pulp, cotton, pulp, cotton, wood chips, chaff, chaff, ground waned shells and other fiber cuttings. Furthermore, short fibers such as glass fiber, glass filament, polyacrylonitrile, carbon fiber, Kevlar fiber or even polyethylene fibers can be added. Aluminum powder is also suitable as a filler.

Also suitable as fillers are hollow spheres with a mineral shell or a plastic shell. These may be, for example, hollow glass spheres or hollow spheres based on plastics. The diameter should be less than 0.5 mm, preferably 300 microns.

The compositions according to the invention should contain from 10 to 50% by weight of silane-group-terminated polyethers, from 0.5 to 20% by weight of (meth) acrylate block copolymers containing at least two hydrolyzable silane groups, and from 85 to 40% by weight of fillers and Excipients, the sum of the ingredients should be 100%. In particular, the proportion of (meth) acrylate block copolymers should be 1 to 10% by weight. The proportion should be based on the proportion of silyl-terminated polyethers, in particular less than 33%. In a preferred embodiment, both polymers have a low dispersity, in particular under 1, 7, in another embodiment, D of the block copolymer should be from 2.0 to 2.4. This makes it possible to keep the viscosity of the composition low.

The crosslinkable compositions according to the invention can be used as a sealant or as adhesives or as a surface coating. The compositions can be applied in a known manner, generally a pretreatment of the substrates is not necessary. The compositions according to the invention can then crosslink under the influence of moisture in the environment. In this case, common networks of the polymeric constituents are formed, which can react with one another via the silane groups. The obtained crosslinked compositions are elastic. They have good adhesion to the various substrates.

In particular, if the substrates have a certain surface moisture, a fast and good adhesion to the surface is observed.

The crosslinked masses are weather-stable. Usually they decompose only slightly under the influence of light. Likewise, also influenced by moisture, even under elevated ambient temperature, stable masses are obtained.

By the use according to the invention of the silane-reactive (meth) acrylate block copolymers, the adhesion to the various substrates is improved. Furthermore, a particularly favorable elasticity behavior of the crosslinked compositions can be determined by the structures of the block copolymers.

The following examples illustrate the invention. Example of Acrylate Block Copolymer 1, 2:

In a jacketed vessel equipped with stirrer, thermometer, reflux condenser, nitrogen inlet tube and dropping funnel, monomer Ib (exact name and quantity in Table 2), 150 ml of propyl acetate, 0.60 g of copper (I) oxide and 1.6 g of N were added under N 2 atmosphere , N, N ^' , N ^" , N ^" -pentamethyldiethylenetriamine (PMDETA). The solution is left for 15 min. stirred at 80 ⁰ C. Subsequently, initiator 1, 4-butanediol di- (2-bromo-2-methylpropionate) (BDBIB, quantity see Table 1) dissolved in 35 ml of propyl acetate is added dropwise at the same temperature. After the polymerization time of three hours, a sample for determining the average molecular weight Mn (by SEC) is taken and a mixture of monomer IIb and monomer IMb (exact name and quantity in Table 2) is added. After a calculated 95% conversion finally monomer IIb '(exact name and quantity in Table 2) is added. The mixture is polymerized to an expected conversion of at least 95% and terminated by addition of 2.4 g of n-dodecylmercaptan. The solution is worked up by filtration through silica gel and subsequent removal of volatiles by distillation. The average molecular weight and the molecular weight distributions Mw / Mn are determined by gel permeation chromatography (GPC) in tetrahydrofuran against a PMMA standard. The proportion of incorporated monomer 3a is quantified by 1 H NMR measurements.

Number average or weight average molecular weights Mn or Mw according to Table 2.

Table 2

MMA = methyl methacrylate; n-BA = n-butyl acrylate, MEMO = Dynasylan MEMO (3-methacryloxypropylthmethoxysilane); 1 GPC measurements of the third step before addition of the mercaptan

For example, polyethersilane 3:

282 g (15 mmol) of polypropylene glycol 18000 (OHZ = 6.0) are dissolved in a 500 ml

Three-necked flask dried at 100 ⁰ C in a vacuum. 0.1 g of DBTL is added at 80 ^° C. under a nitrogen atmosphere, followed by 7.2 g (32 mmol).

Isocyanatopropyltrimethoxysilane added. After stirring for one hour at 80 ° C, the resulting polymer was cooled and treated with 6 g of vinyltrimethoxysilane. Example of sealing compound 4:

Silane-functionalized polyether (B 3) 25%

Polyacrylate B1 3%

Diisoundecylphtalate 17.5%

Chalk U 1 S2 (coated) 49.5%

Vinyltrimethoxysilane (desiccant) 1, 4%

Titanium dioxide 2.5%

Aminopropyltrimethoxysilane (coupling agent) 0.9%

DBTL 0.1%

Stabilizer (Tinuvin) 0.1%

Example of sealing compound 5:

Silane-functionalized polyether (B 3) 22%

Polyacrylate B2 6%

Diisoundecylphtalate 17.5%

Chalk U 1 S2 (coated) 49.5%

Vinyltrimethoxysilane (desiccant) 1, 4%

Titanium dioxide 2.5%

Aminopropyltrimethoxysilane (coupling agent) 0.9%

DBTL 0.1%

Stabilizer (Tinuvin) 0.1%

The polymers are mixed in a high-speed stirrer, after which the pigments are added. Subsequently, the additives, such as catalyst, adhesion promoter, desiccant, mixed and homogenized. The composition of the invention is pasty at room temperature and storable in the absence of water.

The test specimens show on beech wood test specimens after curing

Shear strength of> 3 N / mm ² .

The adhesion to wood, PVC, polycarbonate or ABS specimens is good.

Claims

claims

1. Containing crosslinkable composition

10-50% by weight of silane-terminated polymers having a number average

Molecular weight between 3000 and 30,000 g / mol,

0.5 to 20% by weight of (meth) acrylate block copolymers of the type A (BA) _n , where n = 1 to 5, which contain at least two hydrolyzable silane groups,

85-40 wt .-% of fillers and auxiliaries, wherein the sum of the components should be 100%, characterized in that the (meth) acrylate block copolymers have a number average

Molecular weight of 5000 to 100000 g / mol, the silane groups are contained in at least one block A or B, wherein the silane groups are not terminal of the polymer chain.

2. Crosslinkable composition according to claim 1, characterized in that the silane-terminated polymers are selected from polyethers and / or polyurethanes.

3. Crosslinkable composition according to claim 1 or 2, characterized in that from 1 to 10 silane groups per functionalized block are included.

4. Crosslinkable composition according to claim 3, characterized in that 2 to 4 silane groups per functionalized block are included.

5. Crosslinkable composition according to one of claims 1 to 4, characterized in that n is one or two.

6. Crosslinkable composition according to one of claims 1 to 5, characterized in that the silane groups are contained in both A-end blocks.

7. Crosslinkable composition according to one of claims 1 to 5, characterized in that the silane groups are contained in at least one block B.

8. Crosslinkable composition according to one of claims 1 to 5, characterized in that the silane groups are statistically distributed over each functionalized block or are located as a gradient at the beginning or end of a block.

9. Crosslinkable composition according to one of claims 1 to 8, characterized in that the blocks A and B have a difference of T ₉ of 5 ⁰ C as a copolymer, in particular a difference of more than 10 ⁰ C.

10. Crosslinkable composition according to one of claims 1 to 9, characterized in that 1 to 10 wt .-% (methacrylate block copolymers are included and the amount of acrylate polymers less than 33 wt .-% based on the proportion of silane-terminated polyethers is.

11. The crosslinkable composition according to any one of claims 1 to 10, characterized in that the silane group-terminated polyether has a dispersity of less than 1, 7 or more than 2.4.

12. Crosslinkable composition according to one of claims 1 to 11, characterized in that the fillers and auxiliaries are selected from reactive diluents, pigments, fillers, stabilizers, plasticizers, adhesion promoters, catalysts and / or crosslinkers.

13. Crosslinkable composition according to claim 12, characterized in that 0.01 to 5 wt .-% of a catalyst are contained.

14. Use of a composition according to any one of claims 1 to 13 as a solvent-free sealant, adhesive or coating agent.

15. Use of a composition according to any one of claims 1 to 13 as a sealant in the construction industry.