Rtv-1 silicone composition which is catalyzed in a tin-free manner and which has improved storage stability

Abstract

The invention relates to a moisture-curing silicone composition, comprising at least one crosslinkable polydiorganyl siloxane with alkoxysilane terminal groups, at least one condensation catalyst, at least one crosslinking agent with alkoxysilane groups, and optionally additional contents. The invention is characterized in that the condensation catalyst is a reaction product obtained from a reaction of a metal complex equivalent, comprising between 0.1 and 1 equivalents of a phosphoric or organic phosphonic acid, preferably a partially esterified phosphoric or organic phosphonic acid, wherein the metal complex MC is a titanium (IV), zirconium (IV), or aluminum (III) complex, preferably a titanium (IV) complex, with at least one alkoxy ligand and at least one organic chelating ligand. The composition is particularly suitable as a low-modulus adhesive or sealant and has excellent mechanical properties, such as tensile strength and tear propagation resistance, and an excellent storage stability, in particular in the form of an RTV-1 formulation.

Description

[0001] TIN-FREE CATALYZED RTV-1 SILICONE COMPOSITION WITH IMPROVED STORAGE STABILITY

[0002] Description

[0003] Technical area

[0004] The invention relates to moisture-curing, condensation-curing silicone compositions, their use as elastic adhesives and sealants, and processes for jointing and bonding substrates.

[0005] State of the art

[0006] Silicones are well-known compounds that have long been used as adhesives or sealants. Such silicones can be designed as one- or two-component silicone compositions and typically contain a crosslinkable polydiorganylsiloxane, a crosslinker, and a catalyst as their main components. A distinction is made between cold-curing RTV silicones (RTV = room temperature curing or vulcanizing) and hot-curing HTV silicones (HTV = high-temperature curing or vulcanizing). One- and two-component RTV silicones are also referred to as RTV-1 silicones and RTV-2 silicones, respectively.

[0007] Moisture-curing, condensation-curing RTV silicones have been known for a long time. It is also known that such compositions can cure based on so-called neutral crosslinking. Traditionally, neutral-curing RTV-1 silicones release oxime compounds, whose odor is perceived as highly unpleasant. These compounds are less preferred for health protection reasons and are increasingly subject to legal restrictions. As an alternative to oxime-releasing compositions, neutral-curing RTV-1 silicones can also be formulated with polydiorganylsiloxanes containing alkoxysilane groups. The only decomposition products of the crosslinking process are alcohols, which are split off from the alkoxysilane groups, usually methanol or ethanol, whose odor and toxicological profile are significantly less problematic than with oximes.

[0008] The polydiorganylsiloxanes used in moisture-curing, condensation-curing silicones can be terminated with hydroxyl groups. However, this type of end group has been shown to limit the achievable properties and lead to major problems during the compounding process, especially in the case of RTV-1 silicones. Alternatively, the polydiorganylsiloxanes can be modified with alkyl idialkoxysilyl or trialkoxysilyl end groups. Such modified polymers have been known for a long time. Their preparation via condensation reaction is described, for example, in EP763557 or EP0559045, and their preparation via hydrosilylation reaction is described, for example, in US4898910.

[0009] For use as low-modulus sealants, for example, for sealing joints in sanitary facilities, one-component silicones, i.e., RTV-1 silicones, are often used. When formulated with polydiorganylsiloxanes with alkyldialkoxysilyl or trialkoxysilyl end groups and equipped with tin-based curing catalysts, the resulting compounds often cure with comparatively high modulus, which is not well suited for use as low-modulus adhesives and sealants. Furthermore, tin catalysts are not harmless in terms of environmental and toxicological properties.

[0010] This problem can be partially addressed by using curing catalysts based on titanate, zirconate, or aluminate instead of tin. However, titanate-, zirconate-, or aluminate-catalyzed RTV-1 silicones containing polydiorganylsiloxanes with alkyldialkoxysilyl or trialkoxysilyl end groups are generally not sufficiently stable during storage, especially at elevated temperatures, and they undergo irreversible changes in closed containers after a short time due to undesirable reactions. In extreme cases, they can no longer be used satisfactorily after a short time and must be disposed of. These non-storage-stable compositions, for example, lose their mechanical properties after curing, such as tensile strength or elasticity, or, in the worst case, harden.

[0011] There is therefore a need for easy-to-prepare moisture-curing, condensation-curing silicone compositions based on polydiorganylsiloxanes with alkoxysilyl end groups and condensation catalysts based on titanate, zirconate or aluminate, which are suitable as low-modulus adhesives and sealants and have a sufficiently long open time and, above all, excellent storage stability even at elevated temperatures, thus overcoming the disadvantages of the prior art.

[0012] Description of the invention

[0013] The object of the present invention is therefore to provide a moisture-curing, condensation-curing RTV-1 silicone composition based on polydiorganylsiloxanes with alkoxysilyl end groups and condensation catalysts based on titanate, zirconate or aluminate, which has both a good open time and an exceptionally good storage stability, without significant loss of its mechanical properties after long storage even at elevated temperatures, and which can be used as a low-modulus adhesive and sealant.

[0014] It has surprisingly been found that when using a condensation catalyst in the form of a reaction product obtained from the reaction of one equivalent of a metal complex with between 0.1 and 1 equivalent of a, preferably partially esterified, phosphoric or organic phosphonic acid, wherein the metal complex is a titanium(IV), zirconium(IV) or an aluminum(III) complex, preferably a titanium(IV) complex, with at least one alkoxy ligand and at least one organic chelate ligand, with between 0.1 and 1 equivalent of a, preferably partially esterified, phosphoric or organic phosphonic acid, in an RTV silicone composition based on alkoxysilane-terminated polydiorganosiloxane polymers, an unexpectedly high improvement in storage stability can be achieved, which is extremely surprising in titanate-, zirconate-, or aluminate-catalyzed compositions.Furthermore, a very good open time can be achieved, and the resulting compositions are particularly low modulus, mechanically strong and generally exhibit good adhesion to typical substrates, which makes them particularly suitable as adhesives and sealants.

[0015] Accordingly, the invention relates to a moisture-curing, condensation-crosslinking silicone composition comprising a) at least one crosslinkable polydiorganylsiloxane P having alkoxysilane end groups; b) at least one condensation catalyst K; c) at least one crosslinker V having alkoxysilane groups; d) optionally further ingredients; characterized in that the condensation catalyst K is a reaction product obtained from the reaction of one equivalent of a metal complex MC with between 0.1 and 1 equivalent of a, preferably partially esterified, phosphoric or organic phosphonic acid PO, wherein the metal complex MC is a titanium(IV), zirconium(IV) or an aluminum(III) complex, preferably a titanium(IV) complex, having at least one alkoxy ligand and at least one organic chelate ligand.

[0016] The invention is explained in detail below.

[0017] Ways to implement the invention

[0018] The viscosities stated here can be determined according to DIN 53018. The measurement can be carried out using a cone-and-plate viscometer MCR101 from Anton-Paar, Austria, with a cone type CP 25-1 at 23°C. The stated viscosity values ​​refer to a shear rate of 0.5 s -1 .

[0019] The crosslinking reaction involves hydrolysis and condensation reactions of alkoxysilyl groups. These are known to those skilled in the art and can be schematically represented as follows.

[0020] =Si-OR + H2O =Si-OH + ROH (1) =Si-OH + HO-Si= =Si-O-Si= + H2O (2)

[0021] Upon exposure to water and optionally with the aid of a catalyst, alkoxysilyl groups hydrolyze to form silanols (Si-OH) and an alcohol (step 1). The silanols are generally unstable and condense spontaneously to form siloxane bonds (-Si-O-Si-), thus forming siloxanes (step 2). If more than one alkoxy group is present per Si atom, more highly condensed systems can be formed. In the case of partial hydrolysis, only a portion of the alkoxy groups is hydrolyzed and condensed. The reaction rate of the crosslinking reaction depends on the kinetics of the individual steps. These kinetics can, for example, be 1 H-NMR and 29 Si-NMR experiments for individual components, as described, for example, in “Zeitschrift für Naturforschung (1999), 54b, 155-164” and “Phosphorus, Sulfur, and Silicone and the Related Elements (2011), 186(2), 240-254”.

[0022] The term "homogeneous deep curing" used here refers to the homogeneous curing of a silicone composition in a joint across its entire cross-section. This means that the properties, particularly the mechanical properties such as hardness and elasticity, of the silicone composition after curing are identical on the front and back sides of the joint, within the respective measurement accuracies.

[0023] The composition according to the invention contains a) at least one crosslinkable polydiorganylsiloxane P with alkoxysilane end groups; b) at least one condensation catalyst K; c) at least one crosslinker V with alkoxysilane groups; d) optionally further ingredients; characterized in that the condensation catalyst K is a reaction product obtained from the reaction of one equivalent of a metal complex MC with between 0.1 and 1 equivalent of a, preferably partially esterified, phosphoric or organic phosphonic acid PO, wherein the metal complex MC is a titanium(IV), zirconium(IV) or an aluminum(III) complex, preferably a titanium(IV) complex, with at least one alkoxy ligand and at least one organic chelate ligand.

[0024] The composition according to the invention is a moisture-curing, condensation-curing RTV silicone. This is preferably in the form of a one-component composition (RTV-1 silicone), in which all ingredients are mixed during formulation and the entire mixture is stored in the absence of moisture. With such RTV-1 silicones, curing occurs through contact with water, generally through contact with atmospheric moisture. Alternatively, it can be in the form of a two-component composition (RTV-2). The second component contains, in particular, water, usually dispersed in plasticizer and possibly other additives such as fillers. The composition according to the invention is preferably in the form of a one-component RTV-1 silicone composition.

[0025] Polydiorganylsiloxane P with alkoxysilane end groups

[0026] The composition according to the invention contains at least one crosslinkable polydiorganylsiloxane P with alkoxysilane end groups. Such crosslinkable polydiorganylsiloxanes are well known to those skilled in the art. The crosslinkable polydiorganylsiloxanes have functional groups, in particular two or more functional groups, via which crosslinking is possible. These functional groups can be present in a side group or an end group of the polydiorganylsiloxane, with terminal functional groups being preferred. Such polydiorganylsiloxanes with terminal functional groups are also referred to as α, α-functional polydiorganylsiloxanes. The functional groups of the at least one crosslinkable polydiorganylsiloxane P are alkoxy groups.

[0027] The viscosity of the polydiorganylsiloxanes P used can vary widely depending on the intended use. The polydiorganylsiloxane used according to the invention can, for example, have a viscosity of 10 to 500,000 mPa s, preferably 5,000 to 400,000 mPa s, particularly preferably 6,000 to 350,000 mPa s at a temperature of 23°C.

[0028] The at least one crosslinkable polydiorganylsiloxane P is preferably a linear polydiorganylsiloxane, in particular a polydiorganylsiloxane of the formula (I)

[0029] The residues R 1 , R 2 and R 3 independently of one another represent linear or branched, monovalent hydrocarbon radicals having 1 to 12 C atoms, which optionally contain one or more heteroatoms, and optionally one or more CC multiple bonds and / or optionally cycloaliphatic and / or aromatic moieties.

[0030] In particular, the residues R 1 and R 2 for alkyl radicals having 1 to 5, in particular 1 to 3, carbon atoms, preferably methyl groups. The radicals R 3 independently of one another represent, in particular, phenyl, vinyl or methyl groups. The radicals R 4 independently of one another represent alkoxy groups each having 1 to 13 C atoms, which may optionally contain one or more heteroatoms, and optionally one or more CC multiple bonds and / or optionally cycloaliphatic and / or aromatic moieties.

[0031] Y in formula (I) is a divalent hydrocarbon group having 1 to 8 C atoms, preferably having 2 to 6 C atoms, particularly preferably an ethylene or hexylene bridge, or an oxygen atom, or a group of the general formula (II)

[0032] ' OR 3 '

[0033] -Si-O- (II)

[0034] - OR 3 -I , where R 3has the meaning given above and 1 = 1-5.

[0035] The index m of the general formula (I) is chosen such that the polydiorganylsiloxane P has, for example, the viscosity stated above at a temperature of 23 °C. The index m of the general formula (I) can, for example, be in the range from 10 to 10,000 and preferably from 100 to 1,500.

[0036] The polydiorganylsiloxane P of formula (I) is in particular a polydiorganylsiloxane of formula (Ia). where R 1 , R 2 , R 3 , R 4 and m have the same meanings and the same preferred embodiments as indicated for the polydiorganylsiloxane P of formula (I).

[0037] The at least one crosslinkable polydiorganylsiloxane P is an alkoxy-terminated polydiorganylsiloxane, preferably a crosslinkable alkoxy-terminated polydimethylsiloxane. Preferably used crosslinkable polydiorganylsiloxanes are linear polydiorganylsiloxanes. Thus, radicals R 4 in formula (I) or formula (Ia) independently of one another preferably represent alkoxy groups having 1 to 8 C atoms, which may optionally be substituted by F, N, P, O and / or S.

[0038] The residues R 3 in formula (I) or formula (Ia) can, for example, independently of one another be selected from one or more of the groups methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, n-pentyl, i-pentyl, n-hexyl, i-hexyl, n-heptyl, i-heptyl, n-octyl, i-octyl, cyclopentyl, cyclohexyl, phenyl, vinyl, allyl, methoxymethyl, 2-methoxyethyl, ethoxymethyl, 2-(2-methoxyethoxy)ethyl, trifluoropropyl, 2-aminoethyl, 6-aminohexyl.

[0039] Preferred radicals are R3 in formulas (I) and (Ia) are independently selected from alkyl groups having 1 to 6, in particular having 1 to 3, C atoms, such as propyl, ethyl and methyl, with ethyl and methyl being preferred and methyl being particularly preferred.

[0040] In a particular embodiment, all radicals R 3 in formulas (I) and (Ia) are the same and selected from alkyl groups having 1 to 6, in particular having 1 to 3, C atoms, such as propyl, ethyl and methyl, with methyl and ethyl being preferred and methyl being particularly preferred.

[0041] The polydiorganylsiloxanes of the general formula (I) and / or the formula (Ia) preferably make up at least 90%, preferably at least 95%, particularly preferably at least 99% of the total mass of polydiorganylsiloxane P present in a composition according to the invention.

[0042] Suitable polydiorganosiloxanes, as represented by formula (I) and / or formula (Ia), are known and commercially available. The preparation of such polydiorganosiloxanes also takes place in a known manner, as described, for example, in EP0658588.

[0043] Polydiorganylsiloxanes of general formula (Ia) can be prepared by condensation reaction of OH-terminated polydiorganylsiloxanes with alkoxy-functional silanes or siloxanes. Preparation by condensation reaction can be carried out by processes as described, for example, in EP763557 or EP0559045. Alternatively, polydiorganylsiloxanes of general formula (I) can be prepared by hydrosilylation reaction of vinyl-terminated polydiorganylsiloxanes with Si-H functional alkoxysilanes or siloxanes, or of Si-H terminated polydiorganylsiloxanes with vinyl-functional alkoxysilanes or siloxanes. Preparation by hydrosilylation reaction can be carried out by processes as described, for example, in US4898910.

[0044] In a preferred embodiment, polydiorganylsiloxanes of the general formula (I) and formula (Ia) are prepared by condensation reaction of OH-terminated polydiorganylsiloxanes with alkoxy-functional silanes or siloxanes. In a particularly preferred embodiment, polydiorganylsiloxanes of the general formula (I) and formula (Ia) are prepared by condensation reaction of OH-terminated polydiorganylsiloxanes with alkoxy-functional silanes or siloxanes under catalysis by amidines or guanidines, optionally under co-catalysis of a metal catalyst. Suitable amidine and guanidine catalysts are described, for example, in WO 2016 / 207156 and WO 2015 / 193208.

[0045] In preferred embodiments of the moisture-curing silicone composition, the crosslinkable polydiorganylsiloxane P is prepared in a condensation reaction from OH-terminated polydiorganylsiloxane and a tri- or tetraalkoxysilane, preferably a methyltrialkoxysilane, phenyltrialkoxysilane or a vinyltrialkoxysilane.

[0046] In particularly preferred embodiments of the moisture-curing silicone composition, the reaction of the OH-terminated polydiorganylsiloxane with the tri- or tetraalkoxysilane is carried out in the presence of an amidine or guanidine catalyst.

[0047] The moisture-curing silicone composition preferably contains between 10 wt.% and 60 wt.%, in particular between 15 wt.% and 50 wt.%, preferably between 20 wt.% and 40 wt.% of polydiorganylsiloxane P, based on the total composition.

[0048] Crosslinker V with alkoxysilane groups. The composition according to the invention further comprises at least one crosslinker V with alkoxysilane groups. Alkoxysilane groups are hydrolyzable groups that, optionally with prior hydrolysis and formation of a silanol group, can react with the functional groups of the polydiorganylsiloxane to form a siloxane bond. The reaction between the functional group of the polydiorganylsiloxane and the hydrolyzable group of the crosslinker preferably occurs via a condensation reaction, optionally following a hydrolysis reaction of at least one of the alkoxysilane groups involved. Byproducts such as water or alcohols are generally released in the process.

[0049] Crosslinkers V according to the invention with hydrolyzable radicals correspond in particular to the general formula (III)

[0050] R 5 nSiX4-n (III) where R 5independently of one another is a non-hydrolyzable monovalent hydrocarbon radical having 1 to 18 C atoms, which is saturated or unsaturated and optionally has one or more functional groups containing the elements F, N, P, O and / or S, n is 0, 1, 2 or 3, preferably 0 or 1, X independently of one another is an OH group or a linear or branched alkoxy group having 1 to 8 C atoms, which may optionally be substituted by F, N, P, O and / or S and optionally has unsaturated and / or cycloaliphatic and / or aromatic moieties.

[0051] If X represents an alkoxy group, alkoxy groups X are independently alkoxy groups having 1 to 8 C atoms, which may optionally be substituted by F, N, P, O and / or S and may optionally contain unsaturated and / or cycloaliphatic and / or aromatic moieties. The alkoxy groups X can, for example, be independently selected from one or more of the groups methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, n-pentoxy, i-pentoxy, n-hexoxy, i-hexoxy, n-heptoxy, i-heptoxy, n-octoxy, i-octoxy, cyclopentoxy, cyclohexoxy, phenoxy, vinyloxy, allyloxy, methoxymethoxy, 2-methoxyethoxy, ethoxy methoxy, 2-(2-methoxyethoxy)ethoxy, trifluoropropoxy, 2-aminoethoxy, 6-aminohexoxy.

[0052] Preferably, the alkoxy groups X are independently selected from alkoxy groups having 1 to 6, in particular having 1 to 3, C atoms, such as propoxy, ethoxy and methoxy, with methoxy and ethoxy being preferred and methoxy being particularly preferred.

[0053] In a particular embodiment, all groups X are the same and are selected from alkoxy groups having 1 to 6, in particular 1 to 3, C atoms, such as propoxy, ethoxy and methoxy, with methoxy and ethoxy being preferred and methoxy being particularly preferred.

[0054] Examples of crosslinkers of the general formula (III) are methyltrimethoxysilane, dimethyldimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, i-butyltrimethoxysilane, octyltrimethoxysilane, hexadecyltrimethoxysilane, vinyltrimethoxysilane, vinyltris(2-methoxyethoxy)silane, vinyldimethoxymethylsilane, phenyltrimethoxysilane, Tetramethylorthosilicate, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 2-aminoethyl-3-aminopropyltrimethoxysilane, (Trimethoxysilyl)methyl-O-methylcarbamate, N-(T rimethoxysilyl)methyl)methacrylamide, N- (Trimethoxysilyl)methyl)cyclohexanamine, N,N'-(Methoxy(methyl)silanediyl)dibenzamide and the corresponding compounds in which all methoxy groups are replaced either by ethoxy groups or by propoxy groups, e.g. methyltriethoxysilane, etc.

[0055] In a preferred embodiment of the invention, all groups X are alkoxy groups, particularly preferably methoxy and / or ethoxy groups.

[0056] According to the preceding description, crosslinkers V, in particular crosslinkers V of the general formula (III), can be fully or partially hydrolyzed and condensed to form siloxanes. Such condensed siloxanes can be prepared from one or more different crosslinkers of the general formula (III), wherein at least one of the underlying crosslinkers is a trialkoxysilane or a tetraalkoxysilane, and wherein the average degree of condensation of the siloxane is preferably at least 4. The siloxane is thus preferably an alkoxy-containing condensation product of the monomeric alkoxysilanes of the general formula (III).

[0057] Mono-, di-, tri-, or tetraalkoxysilanes or mixtures thereof can be used for the partial hydrolysis and condensation, with at least one alkoxysilane being a tri- or tetraalkoxysilane. Depending on the alkoxysilanes used and the reaction procedure, in particular the amount of water added, the degree of condensation and the proportion of alkoxy groups remaining in the siloxane formed can be adjusted, with the average degree of condensation of the siloxane preferably being at least 4. The siloxane can consist of linear and / or branched chains, rings, or cages. It is clear to the person skilled in the art that mixtures of such structural elements are usually present. The alkoxysilanes can have non-hydrolyzable groups bonded to the Si atom, in particular monovalent hydrocarbon radicals, which optionally have one or more functional groups, which remain in the siloxane formed. The alcohol formed as a by-product can be removed, e.g.by evaporation in a vacuum. Siloxanes containing alkoxy groups are known and commercially available.

[0058] In addition, monoalkoxysilanes and / or dialkoxysilanes can also be used to produce the alkoxy-containing siloxane. Examples include trimethylmethoxysilane, triethylmethoxysilane, triphenylmethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, and diphenyldimethoxysilane, as well as the corresponding silanes in which all methoxy groups are replaced by either ethoxy or propoxy groups. The monoalkoxysilanes and / or dialkoxysilanes can be used, for example, to adjust the degree of condensation or branching of the resulting siloxane.

[0059] Preferred tri- or tetraalkoxysilanes used to prepare the alkoxy-containing siloxane are methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, tetraethoxysilane, tetramethoxysilane, and mixtures thereof.

[0060] In preferred embodiments of the moisture-curing silicone composition, crosslinker V is selected from alkyl-, alkenyl-, and aryltrimethoxysilanes, optionally further silanes, and / or mixtures of these silanes. Crosslinkers V selected from alkyl-, alkenyl-, and aryltrimethoxysilanes are preferably present in an amount of between 0.1 wt.% and 2.5 wt.%, preferably between 0.5 wt.% and 2 wt.%, based on the total composition.

[0061] In the same or other preferred embodiments of the moisture-curing silicone composition, the composition additionally contains a crosslinker V with adhesion promoter action, preferably selected from tris[3-(trimethoxysilyl)propyl] isocyanurate, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane and any mixtures thereof, in particular in an amount of between 0.1 wt.% and 5 wt.%, preferably between 0.5 wt.% and 4 wt.%, based on the total composition.

[0062] Condensation catalyst K

[0063] The composition according to the invention further contains at least one condensation catalyst K. This serves to catalyze the hydrolysis and condensation taking place between the crosslinkable polydiorganylsiloxane P and the crosslinker V in the presence of moisture or water.

[0064] Condensation catalyst K is a reaction product obtained from the reaction of one equivalent of a metal complex MC, wherein the metal complex MC is a titanium(IV), zirconium(IV) or an aluminum(III) complex, preferably a titanium(IV) complex, with at least one alkoxy ligand and at least one organic chelate ligand, with between 0.1 and 1 equivalent of a, preferably partially esterified, phosphoric or organic phosphonic acid PO.

[0065] Thus, the metal complex MC is a titanate, a zirconate or an aluminate.

[0066] Titanates and organotitanates are compounds that contain at least one ligand bonded to the titanium atom via an acid atom. The same definition applies to zirconates and aluminates, with only the metal atom being different.

[0067] Metal complex MC has at least one organic chelate ligand. Organic chelate ligands are multidentate ligands that comprise carbon and heteroatoms. These are well known to those skilled in the art. The type of organic chelate ligands in metal complex MC is not particularly limited. Their coordination number simply has to be low enough that at least one alkoxy ligand is simultaneously complexed to the metal atom. Bidentate organic chelate ligands are preferred.

[0068] Suitable organic chelate ligands for the metal complex MC include, for example, acetylacetone (acac), ethylenediamine (en), diethylenetriamine (dien), iminodiacetate (ida), triethylenetetramine (trien), bis(salicylidene)ethylenediamine (salen), ethyl acetoacetate (etac), oxalate (ox), tartrate (tart), citrate (cit), dimethylglyoxime (dmg), 8-hydroxyquinoline (oxin), 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen), and 1,2-bis(diphenylphosphino)ethane (dppe). Chelate ligands that complex to the metal via carbonyl oxygen atoms are preferred. Of these, acetylacetone (acac) and ethyl acetoacetate (etac) are particularly preferred.

[0069] In preferred embodiments, the metal complex MC comprises one or two chelating ligands, preferably acetylacetonato ligands and / or ethylacetoacetato ligands.

[0070] The alkoxy ligands on the metal complex MC are not particularly limited. They are preferably C3 to C8 alkoxy ligands, especially branched alkoxy ligands. Propoxy, isopropoxy, and isobutoxy ligands are particularly preferred.

[0071] In preferred embodiments, the metal complex MC comprises one or two alkoxy ligands, preferably alkoxy ligands having 3 to 8 carbon atoms.

[0072] Metal complex MC can be a titanium(IV), zirconium(IV) or aluminum(III) complex, with titanium(IV) complexes being preferred.

[0073] Dialkoxybis(ethylacetoacetato)titanates are the most preferred metal complex MC. These are particularly well-suited for the preparation of condensation catalyst K and result in particularly good catalytic properties. They are also widely available commercially. Suitable dialkoxybis(ethylacetoacetato)titanates are available, for example, under the trade names Tyzor® IBAY (Dorf Ketal), Tytan® S3 (Borica), or Tytan® S6 (Borica).

[0074] For the production of condensation catalyst K, metal complex MC is reacted with a preferably partially esterified phosphoric or organic phosphonic acid PO. One equivalent (molar equivalent) of the metal complex MC is reacted with between 0.1 and 1 equivalent (molar equivalent) of the phosphoric or organic phosphonic acid PO, forming complexes of the phosphoric or organic phosphonic acid PO with the metal complex MC. If two or more equivalents of the phosphoric or organic phosphonic acid PO are used, this completely inactivates the resulting catalyst, and the composition no longer cures. Preferably, between 0.25 and 0.75 equivalents, preferably between 0.4 and 0.6 equivalents, of the preferably partially esterified phosphoric or organic phosphonic acid PO are used for the reaction of one equivalent of the metal complex MC.These preferred ratios lead to particularly advantageous properties in terms of preserved mechanics and storage stability.

[0075] The complexation reaction of phosphoric or organic phosphonic acid PO with the metal complex MC can be described by 31 P and 1 H-NMR spectroscopy. The NMR measurements themselves are known to those skilled in the art and can be performed routinely. The following example refers to a complexation reaction on a titanate. During the reaction, the 31 P-NMR signals of the free (uncomplexed) phosphates (0.25 ppm for a monoester and 1.45 ppm for a diester). When these phosphates are complexed to the titanium atom, new 31 P-NMR signals at -10 ppm and -20 ppm, respectively, are visible in the NMR spectrum of the reaction mixture. At the same time, the ligand exchange in the 1Monitor the H-NMR spectrum of the reaction mixture. The signal of the free P(=O)-OH group of the uncomplexed, partially esterified phosphate at 10.9 ppm disappears.

[0076] The partially esterified phosphoric or organic phosphonic acid PO is preferably either a phosphoric acid diester or a monoester of an organic phosphonic acid. However, it is important that at least one P-OH group is present in the phosphoric or organic phosphonic acid PO. In the latter case, the organic radical is not specifically limited. These are preferably linear or branched alkyl radicals having 3 to 12 carbon atoms. It is preferred if the phosphoric or organic phosphonic acid PO is partially esterified and represents a dialkyl phosphate or an organic monoalkylphosphonate having exactly one P-OH group.

[0077] There are no specific restrictions on the alcohols with which the partially esterified phosphoric or organic phosphonic acid PO is esterified. They are preferably C3 to C12, especially C6 to C10, alcohols, which are preferably branched.

[0078] Suitable and preferred phosphoric or organic phosphonic acids PO are commercially available, for example under the trade names Stabilizer POP® (Wacker), TIB STAB® 115 (TI B Chemicals) or Lakeland® TPA 800 (Lakeland Labs).

[0079] The moisture-curing silicone composition contains in particular between 1.0 wt.% and 3.0 wt.%, preferably between 1.5 wt.% and 2.5 wt.%, of condensation catalyst K, based on the total composition.

[0080] Optional additional ingredients

[0081] The composition according to the invention may optionally contain further components such as those customary for moisture-curing, condensation-curing silicone compositions. Such additional components include, for example, fillers, plasticizers, adhesion promoters, curing accelerators, OH scavengers, drying agents, wetting aids, rheology modifiers, thixotropic agents, processing aids, biocides, UV stabilizers, heat stabilizers, flame retardants, color pigments, odorants, antistatic agents, and / or emulsifiers.

[0082] The composition according to the invention preferably contains at least one of these optional further ingredients.

[0083] In preferred embodiments of the moisture-curing

[0084] Silicone composition, the composition additionally contains at least one filler, in particular in an amount of between 10 wt.% and 60 wt.%, preferably between 25 wt.% and 45 wt.%, based on the total composition.

[0085] For example, fillers can influence both the rheological properties of the uncured composition and the mechanical properties and surface finish of the cured composition. It can be advantageous to use different fillers in one composition.

[0086] Examples of suitable fillers are inorganic or organic fillers, such as natural, ground chalks or highly dried precipitated chalks, both of which may be surface-treated, e.g. with fatty acids;

[0087] Silica, in particular pyrogenic silica, which may be surface-treated, e.g. with silicone oils; aluminum hydroxides such as aluminum trihydroxide, magnesium oxides and hydroxides; carbon black, in particular industrial carbon black; barium sulfate, dolomite; silicas; kaolin; hollow spheres; quartz; calcined aluminum oxides; aluminum silicates; magnesium aluminum silicates; zirconium silicates; cristobalite flour; diatomaceous earth; mica; titanium oxides; zirconium oxides; gypsum; graphite; carbon fibers; zeolites; and glass fibers, the surface of which may be treated with a hydrophobic agent.

[0088] A preferred filler is a ground, in particular uncoated, calcium carbonate, in particular in an amount of between 10 wt.% and 60 wt.%, preferably between 25 wt.% and 45 wt.%, based on the total composition.

[0089] The ground chalk can be coated or uncoated, preferably uncoated. Suitable coatings are known to those skilled in the art and include, for example, stearate coatings and silane coatings. Suitable ground chalks are commercially available in large quantities, for example, the Omyacarb® grades from Omya, such as 1-AV or 5-AV; as well as the Calcilit® and Calciplast® grades from Alpha-Calcit.

[0090] Precipitated chalks are not preferred because they often have a significant water content and require extensive drying to ensure sufficient storage stability.

[0091] All commercially available chalks can be used as ground chalks (calcium carbonates), whereby the ground chalk in preferred embodiments has a particle size d50 between 1 and 5 pm.

[0092] The specification of the particle size or synonymous particle size d50 refers to the fact that 50 wt.% of the particles have a size that is equal to or smaller than the specified value.

[0093] The particle size d50 can typically be determined by laser light scattering according to the ISO 13320:2009 standard, for example with the CILAS 920 instrument from CI LAS or the Malvern Mastersizer 3000 instrument from Malvern Panalytical.

[0094] Suitable ground chalks are available, for example, from the companies Provengale and Omya.

[0095] The filler, in particular the ground chalk, normally has an advantageously low water content due to its manufacturing process. Nevertheless, with regard to storage stability (particularly with RTV-1 compositions), it can be advantageous to additionally dry the fillers. For example, vacuuming at elevated temperature, e.g., at least 60°C, preferably 80°C to 100°C, or without vacuum at 120°C for a prolonged period, e.g., 24 hours, is suitable for this purpose. The water content of the dried filler is preferably <0.2 wt.%, in particular <0.1 wt.%, based on the total weight of the dried filler. The composition according to the invention preferably contains no precipitated silica, since this can impair the storage stability of the composition.

[0096] Fumed silicas, on the other hand, are possible and preferred without restriction. The addition of fumed silicas improves the stability and thixotropic properties of the composition.

[0097] The moisture-curing silicone composition therefore preferably also contains a pyrogenic silica.

[0098] Pyrogenic silicas are contained in particular in an amount of between 0.5 wt.% and 10 wt.%, preferably between 1 wt.% and 5 wt.%, based on the total composition.

[0099] An example of plasticizers that may be used are trialkylsilyl-terminated polydimethylsiloxanes, whereby the trialkylsilyl-terminated polydimethylsiloxanes preferably have a viscosity at 23°C in the range of 1 to 10,000 mPa s. It is also possible to use trimethylsilyl-terminated polydimethylsiloxanes, for example, in which some of the methyl groups are replaced by other organic groups such as phenyl, vinyl or trifluoropropyl groups. The polydimethylsiloxane can also be monofunctional, i.e. one end is reactive, e.g. via a hydroxy end group. Certain hydrocarbons can also be used as plasticizers. Suitable hydrocarbons can be purchased commercially, for example, under the trade name Hydroseal G 232 H from Total.

[0100] Examples of adhesion promoters that may be used are compounds containing silyl groups that carry hydrolyzable residues on the silicon atom, especially epoxysilanes such as 3-glycidoxypropyltrimethoxysilane. Such silanes are classified as crosslinkers of general formula (III) because they can participate in the crosslinking reaction.

[0101] It may be advantageous to combine two or more adhesion promoters. The optionally used OH scavengers are compounds that react with any OH groups present. OH groups can be present as uncapped chain ends of polydiorganylsiloxanes, as OH groups on fillers, and as water. OH scavengers can be Si-N-containing compounds. Examples of OH scavengers are hexamethyldisilazane (HMDZ), hexamethylcyclotrisilazane, octamethyltetrasilazane, and bis(trimethylsilyl)urea. HMDZ is the most preferred OH scavenger.

[0102] All components of the moisture-curing, condensation-curing composition can be mixed together in the usual way. For this purpose, the individual components are thoroughly mixed together in suitable mixing units, e.g., forced-action mixers, planetary mixers, mixing tubes, kneaders, dissolvers, or extruders. Mixing can be carried out continuously or in a batch process. The crosslinkable polydiorganylsiloxane P according to the invention, in particular one of the general formula (I) or formula (Ia), can be prepared in a separate, upstream reaction, optionally stored temporarily, and then metered into the mixing unit in a suitable amount.Alternatively, it is also possible, and partly preferred, to prepare the crosslinkable polydiorganylsiloxane P, in particular one of the general formula (I) or the formula (Ia), directly in the mixing unit as described above and to add and mix the other ingredients after completion of this preparation, without processing and / or intermediate storage of the polydiorganylsiloxane P.

[0103] In a preferred embodiment, the composition according to the invention is a one-component composition that cures via atmospheric moisture.

[0104] The composition according to the invention can be used as an adhesive or sealant in a process for bonding or jointing substrates.

[0105] Thus, one aspect of the invention is a method for bonding or jointing substrates. The method for bonding or jointing substrates with a moisture-curing composition according to the present invention and the previous description comprises: a) optionally mixing any components of the composition stored in different containers to obtain a complete mixture of all ingredients of the composition, b) applying the completely mixed composition to a substrate and joining the mixture applied to the substrate to another substrate to obtain an adhesive bond between the substrates, or introducing the mixture into a joint between two substrates to obtain a bond between the substrates, and c) curing the composition thus applied by exposure to moisture, in particular atmospheric humidity.

[0106] Any mixing required according to step a) can therefore be performed before or during application or introduction according to step b). Mixing should be performed relatively shortly before further processing, as the curing process begins with mixing. Naturally, step a) is omitted when using an RTV-1 formulation.

[0107] Application to a substrate or introduction into a joint between substrates according to step b) can be carried out in a conventional manner, e.g. by hand or in an automated process using robots. During bonding, the substrate provided with the mixture is brought into contact with another substrate, optionally under pressure, in order to obtain an adhesive bond between the substrates. Thereafter, in step c), the mixture is allowed to cure, usually at room temperature, in order to achieve the bonding or sealing of the substrates. In this way, the bonded or sealed substrates according to the invention are obtained with the cured mixture as an adhesive or sealing material. The substrates to be bonded or sealed can be made of the same or a different material. All conventional materials can be bonded or sealed with the two-component composition according to the invention.Preferred materials for bonding or jointing are glass, metals such as aluminum, copper, steel or stainless steel, concrete, mortar, building blocks such as sandstone and sand-lime brick, asphalt, bitumen, plastics such as polyolefins, PVC, Tedlar, PET, polyamide, polycarbonate, polystyrene or polyacrylate and composite materials such as CFRP.

[0108] The two-component composition according to the invention can thus be used as an adhesive or sealant, e.g. in the fields of construction, sanitary, automotive, solar technology, wind power technology, white goods, facade and window construction, electronics and boat and ship building.

[0109] Accordingly, a further subject matter of the invention is the use of a composition according to the invention as described above as an adhesive, sealant, coating or potting compound, in particular in the fields of construction, sanitary, automotive construction and maintenance, solar technology, wind power technology, white goods, facade and window construction, electronics and boat and ship building.

[0110] A further subject of the invention are bonded or grouted substrates obtainable by a process as just described.

[0111] Examples

[0112] Specific embodiments of the invention are described below; however, these are not intended to limit the scope of the invention. All tests were carried out at 23°C and 50% RH (relative humidity). The proportions of the components for the silicone compositions specified in Tables 3, 5, and 7 below were weighed one after the other and mixed in a Hauschild speed mixer at 23°C and 50% relative humidity for 20 seconds at 2000 revolutions per minute while applying a vacuum. All numerical values ​​of the ingredients in Tables 3, 5, and 7 refer to parts by weight (e.g., in grams) of the respective ingredient added to the respective composition. The resulting compositions were sealed airtight, stored at 23°C for 24 hours, and then tested.Some samples were additionally artificially aged for 7 days at 70°C in closed containers before being stored at 23°C for 24 hours and subsequently tested.

[0113] The Shore A hardness was determined after 7 days of curing using a Bareiss Shore A test device according to DIN ISO 7619-1. To determine the Shore A hardness, round test specimens with a diameter of 42 mm and a thickness of 6 mm were prepared.

[0114] The method for determining elongation at break, tensile strength, and stress at 100% elongation, as well as the preparation of the required test specimens, is described in ISO 527. Measurements were performed at 23°C and 50% relative humidity using a Type 1 B test specimen (ISO 527-2) at a tensile speed of 200 mm / min. The composites were preliminarily ironed into 2 mm thick sheets and cured for 7 days.

[0115] The method for determining tear resistance ("WRW") and the preparation of the required test specimens are described in DIN ISO 34-1. Measurements were performed on Type C test specimens.

[0116] To determine the skin formation time («HBZ»), the composition to be tested was applied to an area of ​​approximately 20 cm 2 Spread to a thickness of approximately 1 cm. Care was taken to ensure the surface was smooth. The time of spreading marked the start of the measurement. A PE pipette was applied to the surface of the hardening composition. The skin formation time was reached when the PE pipette could be removed without visible adhesion. Viscosity was determined according to DIN EN ISO 3219 using an MCR101 cone-and-plate viscometer from Anton-Paar, Austria, with a cone type CP 25-1 and a distance of 0.049 mm at 23°C. The stated viscosity values ​​refer to a shear rate of 0.9 s -1 .

[0117] Abbreviations of the chemicals used can be found in Table 1 below. All polymers are based on linear polydimethylsiloxane (PDMS). Unless otherwise stated, all chemicals are commercially available from chemical retailers (e.g., Sigma-Aldrich).

[0118] Table 1: Ingredients used. Production of condensation converters K

[0119] A series of condensation catalysts K were prepared by mixing titanate TH and phosphate PO1 in a defined ratio at room temperature and allowing them to react. In each case, a phosphate complex was formed on the titanate. The reaction can be described by 31 P and 1H NMR spectroscopy. The NMR measurements themselves are familiar to those skilled in the art and can be performed routinely. During the reaction, the 31P-NMR signals in the NMR spectrum of the reaction mixture of the free (uncomplexed) phosphates (0.25 ppm for a monoester and 1.45 ppm for a diester). When these phosphates are complexed to the titanium atom, signals at -10 ppm and -20 ppm, respectively, are observed in the 31 P-NMR spectrum visible.

[0120] At the same time, the complexation progress in 1 H-NMR spectrum of the reaction mixture. The signal of the free P(=O)-OH group of the uncomplexed, partially esterified phosphate at 10.9 ppm disappears.

[0121] In the preparation of the condensation catalysts K, the reaction was carried out until the 31 P-NMR and 1H-NMR spectra demonstrated complete complexation of the phosphate esters used. The resulting condensation catalysts K were then used without further processing. Table 2 shows the prepared condensation catalysts K and the amounts of titanate TU and phosphate PO1 used.

[0122] Table 2: Catalysts K prepared. * not according to the invention

[0123] In another experiment, titanate TI3 was complexed with phosphate PO1, similar to the preparation of catalyst K1. However, an insoluble complex was formed, which was completely inactive in an example formulation as shown in Table 3. This composition subsequently did not cure. This demonstrates that ligands that positively influence solubility or miscibility in silicone matrices, such as ethyl acetoacetate ligands on titanate TI, are advantageous.

[0124] The same can be observed further down in Table 6 with titanate TI2. Although this titanate TI is a complex with phosphate PO ligands, it also lacks the ethyl acetoacetate ligands. This leads to significantly poorer storage stability than in the inventive experiments using catalysts K.

[0125] Table 3: Formulation details and some measurement results from tests E1 to E10. "n / m" means not measured. * Non-inventive reference tests.

[0126] Table 4: Measurement results after curing of tests E1 to E10. "n / m" means not measured. * Reference tests not according to the invention.

[0127] The results in Table 4 show that the inventive catalyst K1 consistently leads to higher storage stability (measured by comparing mechanical values, here tensile strength and stress at 100% elongation, which are important properties for adhesives and sealants). Compositions catalyzed according to the invention exhibit a smaller difference in these mechanical properties when freshly produced and artificially aged material are tested and compared. Artificial aging was carried out in all examples by storing a produced sample in a sealed container for 7 days at 70°C. With such heat storage, the storage stability of a composition can be determined through simulated, accelerated aging.It is particularly noteworthy that the complexed catalyst K1 according to the invention leads to a higher storage stability than when the titanate TH and the esterified phosphoric acid PO1 used for this purpose are added individually (not pre-complexed) (comparison E2* with E3).

[0128] Table 5: Formulation details and some measurement results from tests E11 to E15. "n / m" means not measured. * Non-inventive reference tests, "n / h" means that the sample is no longer cured after 7 days of curing under standard conditions.

[0129] Table 6: Measurement results after curing of tests E11 to E15. "n / m" means not measured. * Non-inventive reference tests. "n / h" means that the composition was not cured after a curing time of 7 days under standard conditions and could not be measured.

[0130] Table 7: Formulation details and some measurement results from tests E16 to E20. * Non-inventive reference tests.

[0131] Table 8: Measurement results after curing of tests E16 to E20. Non-inventive reference tests.

[0132] The results in Table 6 show that the inventive catalysts K, which were prepared according to claim 1, lead to very good storage stability (expressed by only minimal changes in mechanical properties after curing). Reference test E14, using a commercial catalyst, largely lost its mechanical properties after artificial aging of the uncured composition. Reference test E15 did not cure at all, as the catalyst not prepared according to the invention was completely inactive.

[0133] The results in Table 8 show that the pre-reaction of the metal complex MC with the phosphoric or organic phosphonic acid PO has a positive effect on storage stability even with small amounts of phosphoric or organic phosphonic acid PO. The optimum is achieved when a mixing ratio of approximately 4:1 metal complex MC to phosphoric or organic phosphonic acid PO is achieved. Increasing the concentration of the phosphoric or organic phosphonic acid PO to a ratio of 2:1 does not bring any further improvement and primarily leads to a longer skin formation time (see test E15 in Table 6).

Claims

Patent claims 1. Moisture-curing silicone composition comprising a) at least one crosslinkable polydiorganylsiloxane P with alkoxysilane end groups; b) at least one condensation catalyst K; c) at least one crosslinker V with alkoxysilane groups; d) optionally further ingredients; characterized in that the condensation catalyst K is a reaction product obtained from the reaction of one equivalent of a metal complex MC with between 0.1 and 1 equivalent of a, preferably partially esterified, phosphoric or organic phosphonic acid PO, wherein the metal complex MC is a titanium(IV), zirconium(IV) or an aluminum(III) complex, preferably a titanium(IV) complex, with at least one alkoxy ligand and at least one organic chelate ligand.

2. Moisture-curing silicone composition according to claim 1, characterized in that the metal complex MC comprises one or two alkoxy ligands, preferably alkoxy ligands having 3 to 8 carbon atoms.

3. Moisture-curing silicone composition according to claim 1 or 2, characterized in that the metal complex MC comprises one or two chelate ligands, preferably acetylacetonato ligands and / or ethylacetoacetato ligands.

4. Moisture-curing silicone composition according to one of the preceding claims, characterized in that the crosslinkable polydiorganylsiloxane P is obtained in a condensation reaction from OH-terminated polydiorganylsiloxane and a tri- or Tetraalkoxysilane is prepared, preferably a methyltrialkoxysilane, phenyltrialkoxysilane or a vinyltrialkoxysilane.

5. Moisture-curing silicone composition according to claim 4, characterized in that the reaction of the OH-terminated polydiorganylsiloxane with the tri- or tetraalkoxysilane is carried out in the presence of an amidine or guanidine catalyst.

6. Moisture-curing silicone composition according to one of the preceding claims, characterized in that crosslinker V is selected from alkyl-, alkenyl- and aryltrimethoxysilanes, optionally further silanes and / or mixtures of these silanes.

7. Moisture-curing silicone composition according to one of the preceding claims, characterized in that the phosphoric or organic phosphonic acid PO is partially esterified and represents a dialkyl phosphate or an organic monoalkyl phosphonate having exactly one P-OH group.

8. Moisture-curing silicone composition according to one of the preceding claims, characterized in that in the reaction of one equivalent of a metal complex MC between 0.25 and 0.75 equivalents, preferably between 0.4 and 0.6 equivalents, of the preferably partially esterified phosphoric or organic phosphonic acid PO are used.

9. Moisture-curing silicone composition according to one of the preceding claims, characterized in that the composition contains between 1.0 wt.% and 3.0 wt.%, preferably between 1.5 wt.% and 2.5 wt.%, based on the total composition, of condensation catalyst K.

10. Moisture-curing silicone composition according to one of the preceding claims, characterized in that the composition additionally contains a crosslinker V with adhesion promoter action, preferably selected from tris[3-(trimethoxysilyl)propyl] isocyanurate, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane and any mixtures thereof, in particular in an amount of between 0.1 wt.% and 5 wt.%, preferably between 0.5 wt.% and 4 wt.%, based on the total composition.

11. Moisture-curing silicone composition according to one of the preceding claims, characterized in that the composition additionally contains at least one filler, preferably a ground, in particular uncoated calcium carbonate, in particular in an amount of between 10 wt.% and 60 wt.%, preferably between 25 wt.% and 45 wt.%, based on the total composition.

12. Moisture-curing silicone composition according to one of the preceding claims, characterized in that plasticizers, adhesion promoters, curing accelerators, OH scavengers, drying agents, wetting aids, rheology modifiers, thixotropic agents, processing aids, biocides, UV stabilizers, heat stabilizers, flame retardants, color pigments, odorants, antistatic agents, and / or emulsifiers are included as further ingredients.

13. Moisture-curing silicone composition according to one of claims 1 to 12, characterized in that the composition is a one-component silicone composition.

14. Use of a composition according to any one of the preceding claims as an adhesive, sealant, coating or Casting compound, particularly in the areas of construction, plumbing, automotive manufacturing and maintenance, solar technology, wind power technology, white goods, facade and window construction, electronics and boat and ship building.

15. A method for bonding or jointing substrates with a moisture-curing composition according to any one of claims 1-13, comprising a) optionally mixing any components of the composition stored in different containers to obtain a complete mixture of all ingredients of the composition, b) applying the completely mixed composition to a substrate and joining the mixture applied to the substrate to another substrate to obtain an adhesive bond between the substrates, or introducing the mixture into a joint between two substrates to obtain a bond between the substrates, and c) curing the composition thus applied by exposure to moisture, in particular atmospheric humidity.

Images