RTV-1 silicone compositions catalyzed in tin-free manner and having improved storage stability

Abstract

Described is a moisture-curable silicone composition comprising at least one crosslinkable polydiorganosiloxane having alkoxysilane end groups, at least one condensation catalyst, at least one crosslinking agent having alkoxysilane groups, and optionally further ingredients; characterised in that the condensation catalyst is the reaction product obtained from the reaction of 1 equivalent of a metal complex with 0.1 to 1 equivalent of a preferably partially esterified phosphoric acid or organic phosphonic acid, where the metal complex MC is a titanium (IV), zirconium (IV) or aluminum (III) complex, preferably a titanium (IV) complex, having at least one alkoxy ligand and at least one organic chelate ligand. The compositions are particularly suitable as low modulus adhesives or sealants and have excellent mechanical properties such as tensile strength and tear propagation resistance as well as excellent storage stability, especially in the form of RTV-1 formulations.

Description

Technical Field

[0001] This invention relates to moisture-curing, condensation-crosslinking silicone compositions, their use as elastic adhesives and sealants, and methods for bonding and adhering substrates.

[0002] Existing technology

[0003] Silicone is a known composition that has long been used as an adhesive or sealant. It can be formulated as a one-component or two-component silicone composition and typically contains a crosslinkable polydiorganosiloxane, a crosslinking agent, and a catalyst as the main components. It is distinguished as cold-crosslinked RTV silicone (RTV = room temperature crosslinking / curing) and heat-crosslinked HTV silicone (HTV = high temperature crosslinking / curing). One-component and two-component RTV silicones are also referred to as RTV-1 silicone and RTV-2 silicone, respectively.

[0004] Moisture-cured, condensation-crosslinked RTV silicones have long been known. It is also known that such compositions can be cured based on so-called neutral crosslinking. Typically, neutrally crosslinked RTV-1 silicones release oxime compounds, whose odor is considered very unpleasant and is less preferred for health protection reasons, and is increasingly subject to legal restrictions. As an alternative to oxime-releasing compositions, neutrally crosslinked RTV-1 silicones can also be formulated using polydiorganosiloxanes containing alkoxysilyl groups. The cleavage products of the crosslinking are simply alcohols, typically methanol or ethanol, cleaved from the alkoxysilyl groups, and their odor and toxicological characteristics are significantly less problematic than those of oximes.

[0005] Polydiorganosiloxanes used in moisture-cured, condensation-crosslinked silicones can be end-capped with hydroxyl groups. However, this type of end group has been found to limit achievable properties and cause major problems during compounding, especially in the case of RTV-1 silicones. Alternatively, polydiorganosiloxanes can be modified with alkyldialkoxysilyl or trialkoxysilyl end groups. Such modified polymers have long been known. Their preparation by condensation reactions is described, for example, in EP763557 or EP 0559045; their preparation by hydrosilylation reactions is described, for example, in US4898910.

[0006] One-component silicones, namely RTV-1 silicones, are commonly used as low-modulus sealants, such as for joint sealing in sanitary areas. When these one-component silicones are formulated with polydiorganosiloxanes having alkyldialkoxysilyl or trialkoxysilyl end groups and endowed with a tin-based curing catalyst, the result is typically a composition with relatively high-modulus curing that is unsuitable for use as a low-modulus adhesive and sealant. Furthermore, the environmental and toxicological properties of tin catalysts are not without controversy.

[0007] This problem can sometimes be addressed by using curing catalysts based on titanates, zirconates, or aluminates instead of tin-based curing catalysts. However, RTV-1 silicones catalyzed by titanates, zirconates, or aluminates containing polydiorganosiloxanes with alkyldialkoxysilyl or trialkoxysilyl end groups generally exhibit insufficient storage stability, especially at elevated temperatures, and they undergo irreversible changes in sealed containers after a short period due to undesirable reactions, making them unusable and requiring disposal in extreme cases. Furthermore, these storage-unstable compositions lose, for example, their mechanical properties after curing, particularly tensile strength or elasticity, or, in the worst case, fail to cure at all.

[0008] Therefore, there is a need for readily prepareable moisture-curing condensation-crosslinked silicone compositions based on polydiorganosiloxanes with alkoxysilyl end groups and condensation catalysts based on titanates, zirconates, or aluminates, which are suitable as low-modulus adhesives and sealants, have sufficiently long open times, and, in particular, exhibit excellent storage stability even at elevated temperatures, thereby overcoming the shortcomings of the prior art. Invention Overview

[0010] Therefore, one object of the present invention is to provide a moisture-curing condensation crosslinking RTV-1 silicone composition based on a polydiorganosiloxane having an alkoxysilyl end group and a condensation catalyst based on titanate, zirconate or aluminate, which has good open time and exceptionally good storage stability, does not significantly lose its mechanical properties even after long-term storage at high temperature, and can be used as a low modulus adhesive and sealant.

[0011] Surprisingly, it has been found that when the condensation catalyst used is in the form of a reaction product obtained by reacting a 1-equivalent metal complex with 0.1 to 1-equivalent preferably partially esterified phosphoric acid or organophosphonic acid (wherein the metal complex is a titanium(IV), zirconium(IV), or aluminum(III) complex having at least one alkoxy ligand and at least one organic chelate ligand, preferably a titanium(IV) complex), the use of 0.1 to 1-equivalent preferably partially esterified phosphoric acid or organophosphonic acid in RTV silicone compositions based on alkoxysilane-terminated polydiorganosiloxane polymers can achieve unexpectedly high improvements in storage stability, which is particularly surprising in compositions catalyzed by titanates, zirconates, or aluminates. Furthermore, very good open times can be achieved, and the resulting compositions have particularly low modulus, high mechanical strength, and generally good adhesion to typical substrates, making them particularly suitable as adhesives and sealants.

[0012] Therefore, the present invention relates to a moisture-curing condensation-crosslinked silicone composition comprising:

[0013] a) At least one crosslinkable polydiorganosiloxane P having an alkoxysilane end group;

[0014] b) At least one condensation catalyst K;

[0015] c) At least one crosslinking agent V having an alkoxysilyl group;

[0016] d) Optional other ingredients;

[0017] Characterized by the fact that the condensation catalyst K is a reaction product obtained by reacting 1 equivalent of a metal complex MC with 0.1 to 1 equivalent of (preferably partially esterified) phosphoric acid or organophosphonic acid PO, wherein the metal complex MC is a titanium (IV), zirconium (IV) or aluminum (III) complex, preferably a titanium (IV) complex, having at least one alkoxy ligand and at least one organic chelate ligand.

[0018] The invention is described in detail below.

[0019] Embodiments of the present invention

[0020] The viscosities reported in this paper can be determined according to DIN 53018. Measurements can be performed at 23°C using an MCR101 cone-plate viscometer with a CP 25-1 cone from Anton Paar, Austria. The reported viscosity values ​​per 0.5 s⁻¹ are for reference only. -1 The shear rate.

[0021] The crosslinking reaction involves the hydrolysis and condensation of alkoxysilyl groups. These are known to those skilled in the art and can be illustrated as follows:

[0022] ≡Si-OR + H2O → ≡Si-OH + ROH (1)

[0023] ≡Si-OH + HO-Si≡ → ​​≡Si-O-Si≡ + H2O (2)

[0024] Upon the introduction of water and optionally with the aid of a catalyst, the alkoxysilyl group is hydrolyzed to form a silanol (Si-OH) and an alcohol (step 1). The silanol is generally unstable and spontaneously condenses to form a siloxane bond (-Si-O-Si-), thereby forming a siloxane (step 2). If more than one alkoxy group is present per silicon atom, a more highly condensed system may be formed. In the case of partial hydrolysis, only some alkoxy groups are hydrolyzed and condensed. The reaction rate of the crosslinking reaction depends on the step-by-step kinetics. These kinetics can be, for example, in the case of a single component. 1 H NMR and 29Si was determined in NMR experiments, as described, for example, in “Zeitschrift für Naturforschung (1999), 54b, 155-164” and “Phosphorus, Sulfur, and silicones and the Related Elements (2011), 186(2), 240-254”.

[0025] The term "uniform depth curing" as used in this article refers to the uniform curing of the silicone composition at the joint across the entire cross-section. This means that after curing on both the front and back sides of the joint, the properties of the silicone composition, especially mechanical properties such as hardness and elasticity, are identical within their respective measurement accuracy ranges.

[0026] The composition of the present invention comprises:

[0027] a) At least one crosslinkable polydiorganosiloxane P having an alkoxysilane end group;

[0028] b) At least one condensation catalyst K;

[0029] c) At least one crosslinking agent V having an alkoxysilyl group;

[0030] d) Optional other ingredients;

[0031] Characterized by the fact that the condensation catalyst K is a reaction product obtained by reacting 1 equivalent of a metal complex MC with 0.1 to 1 equivalent of (preferably partially esterified) phosphoric acid or organophosphonic acid PO, wherein the metal complex MC is a titanium (IV), zirconium (IV) or aluminum (III) complex, preferably a titanium (IV) complex, having at least one alkoxy ligand and at least one organic chelate ligand.

[0032] The compositions of the present invention are moisture-curing, condensation-crosslinked RTV silicones. They are preferably present as a one-component composition (RTV-1 silicone), wherein all components of the formulation are mixed and the entire mixture is stored with moisture removed. This RTV-1 silicone is cured by contact with water, typically by contact with air moisture. Alternatively, they may be present as a two-component composition (RTV-2). The second component specifically contains water and is typically dispersed in plasticizers and possibly other additives such as fillers. The compositions of the present invention are preferably present as a one-component RTV-1 silicone composition.

[0033] Polydiorganosiloxane P with alkoxysilane end groups

[0034] The compositions of the present invention contain at least one crosslinkable polydiorganosiloxane P having an alkoxysilane end group. Such crosslinkable polydiorganosiloxanes are well known to those skilled in the art. The crosslinkable polydiorganosiloxane has functional groups, particularly two or more functional groups, through which crosslinking is possible. These functional groups may be present in the side groups or end groups of the polydiorganosiloxane, preferably terminal functional groups. Such polydiorganosiloxanes with terminal functional groups are also called α,ω-functionalized polydiorganosiloxanes. The functional group of the at least one crosslinkable polydiorganosiloxane P is an alkoxy group.

[0035] Depending on the intended use, the viscosity of the polydiorganosiloxane P used can vary over a wide range. The polydiorganosiloxane used according to the present invention can have a viscosity of, for example, 10-500,000 mPa·s, preferably 5,000-400,000 mPa·s, and more preferably 6,000-350,000 mPa·s at a temperature of 23°C.

[0036] The at least one crosslinkable polydiorganosiloxane P is preferably a linear polydiorganosiloxane, especially a polydiorganosiloxane of formula (I):

[0037]

[0038] R here 1 R 2 and R 3 The group is independently a straight-chain or branched monovalent hydrocarbon group having 1 to 12 carbon atoms, which optionally includes one or more heteroatoms, and optionally one or more C-C multiple bonds and / or optionally alicyclic and / or aromatic moieties.

[0039] In particular, the group R 1 and R 2 It is an alkyl group having 1-5, especially 1-3, carbon atoms, preferably methyl. R 3 The groups are independent, especially phenyl, vinyl, or methyl.

[0040] R 4 The groups are independently alkoxy groups each having 1 to 13 carbon atoms, optionally including one or more heteroatoms, and optionally one or more C-C multiple bonds and / or optionally alicyclic and / or aromatic moieties.

[0041] In formula (I), Y is a divalent hydrocarbon group having 1 to 8 carbon atoms, preferably 2 to 6 carbon atoms, more preferably an ethylene or hexene bridge, or an oxygen atom, or a group of general formula (II).

[0042]

[0043] Where R 3 It has the definition given above and l=1-5.

[0044] The exponent m in general formula (I) is chosen such that the polydiorganosiloxane P has the above-mentioned viscosity, for example, at a temperature of 23°C. The exponent m in general formula (I) can be in the range of 10-10000, preferably 100-1500.

[0045] Polydiorganosiloxane P of formula (I), especially polydiorganosiloxane of formula (Ia).

[0046]

[0047] Where R 1 R 2 R 3 R 4 The terms m and m have the same meaning and the same preferred embodiment as described in the case of polydiorganosiloxane P of formula (I).

[0048] The at least one crosslinkable polydiorganosiloxane P is an alkoxy-terminated polydiorganosiloxane, preferably a crosslinkable alkoxy-terminated polydimethylsiloxane. Preferably, the crosslinkable polydiorganosiloxane used is a linear polydiorganosiloxane. Therefore, R in formula (I) or formula (Ia) 4 The groups are preferably alkoxy groups having 1-8 carbon atoms, which may optionally be substituted with F, N, P, O and / or S.

[0049] R in equation (I) or equation (Ia) 3 The groups may be selected independently from one or more of the following group: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl, n-hexyl, isohexyl, n-heptyl, isoheptyl, n-octyl, isooctyl, cyclopentyl, cyclohexyl, phenyl, vinyl, allyl, methoxymethyl, 2-methoxyethyl, ethoxymethyl, 2-(2-methoxyethoxy)ethyl, trifluoropropyl, 2-aminoethyl, 6-aminohexyl.

[0050] R in equations (I) and (Ia) 3 The groups are preferably selected independently from alkyl groups having 1 to 6, especially 1 to 3, carbon atoms, such as propyl, ethyl, and methyl, with ethyl and methyl being preferred, and methyl being particularly preferred.

[0051] In a particular implementation, all R in equations (I) and (Ia) 3 The groups are identical and selected from alkyl groups having 1 to 6, especially 1 to 3, carbon atoms, such as propyl, ethyl, and methyl, preferably methyl and ethyl, and particularly preferably methyl.

[0052] The polydiorganosiloxane of general formula (I) and / or formula (Ia) preferably accounts for at least 90% of the total mass of the polydiorganosiloxane P present in the composition of the present invention, preferably at least 95%, more preferably at least 99%.

[0053] Suitable polydiorganosiloxanes as shown in formula (I) and / or formula (Ia) are known and commercially available. Such polydiorganosiloxanes are also prepared in a known manner, for example, as described in EP0658588.

[0054] Polydiorganosiloxanes of general formula (Ia) can be prepared by a condensation reaction of an OH-terminated polydiorganosiloxane with an alkoxy-functionalized silane or siloxane. Preparation by condensation reaction can be carried out, for example, by the method described in EP 763557 or EP 0559045. Alternatively, polydiorganosiloxanes of general formula (I) can be prepared by a hydrosilylation reaction of a vinyl-terminated polydiorganosiloxane with a Si-H-functionalized alkoxysilane or siloxane, or by a Si-H-terminated polydiorganosiloxane with a vinyl-functionalized alkoxysilane or siloxane. Preparation by hydrosilylation reaction can be carried out, for example, by the method described in US 4898910.

[0055] In a preferred embodiment, polydiorganosiloxanes of general formula (I) and formula (Ia) are prepared by a condensation reaction of an OH-terminated polydiorganosiloxane with an alkoxy-functionalized silane or siloxane. In a particularly preferred embodiment, polydiorganosiloxanes of general formula (I) and formula (Ia) are prepared by a condensation reaction of an OH-terminated polydiorganosiloxane with an alkoxy-functionalized silane or siloxane under the catalysis of an amidine or guanidine, optionally with the co-catalysis of a metal catalyst. Suitable amidine and guanidine catalysts are described, for example, in WO 2016 / 207156 and WO 2015 / 193208.

[0056] In a preferred embodiment of the moisture-curing silicone composition, the crosslinkable polydiorganosiloxane P is prepared in the condensation reaction of an OH-terminated polydiorganosiloxane and a trimekoxysilane or tetraalkoxysilane, preferably a methyltrialkoxysilane, a phenyltrialkoxysilane or a vinyltrialkoxysilane.

[0057] In a particularly preferred embodiment of the moisture-curing silicone composition, the reaction of the OH-terminated polydiorganosiloxane with a trialkoxysilane or a tetraalkoxysilane is carried out in the presence of an amidine or guanidine catalyst.

[0058] The moisture-curing silicone composition preferably contains 10% to 60% by weight, particularly 15% to 50% by weight, and preferably 20% to 40% by weight of polydiorganosiloxane P, based on the total composition.

[0059] Crosslinking agent V with alkoxysilyl group

[0060] The compositions of the present invention further comprise at least one crosslinking agent V having an alkoxysilyl group. The alkoxysilyl group is a hydrolyzable group that, where appropriate, can react with the functional groups of a polydiorganosiloxane to form a siloxane bond after prior hydrolysis and the formation of silanol groups. The reaction between the functional groups of the polydiorganosiloxane and the hydrolyzable group of the crosslinking agent is preferably carried out by a condensation reaction, optionally following the hydrolysis of at least one of the alkoxysilyl groups involved. Typically, this releases byproducts such as water or alcohol.

[0061] The crosslinking agent V of the present invention, having hydrolyzable groups, particularly conforms to general formula (III).

[0062] R 5 n SiX 4-n (III)

[0063] Where R 5 Each of the groups is a monovalent hydrocarbon group having 1 to 18 carbon atoms that is independent of hydrolysis, is saturated or unsaturated and optionally has one or more functional groups containing elements F, N, P, O and / or S, n is 0, 1, 2 or 3, preferably 0 or 1, and X is an OH group or a straight-chain or branched alkoxy group having 1 to 8 carbon atoms and optionally being substituted by F, N, P, O and / or S and optionally having unsaturated and / or alicyclic and / or aromatic moieties.

[0064] If X is an alkoxy group, then the alkoxy group X is independently selected from one or more of the following: methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, pentooxy, isopentoxy, hexoxy, isohexoxy, heptoxy, isohexoxy, octoxy, isooctoxy, cyclopentoxy, cyclohexoxy, phenoxy, vinyloxy, allyloxy, methoxymethoxy, 2-methoxyethoxy, ethoxymethoxy, 2-(2-methoxyethoxy)ethoxy, trifluoropropoxy, 2-aminoethoxy, and 6-aminohexoxy.

[0065] The alkoxy group X is preferably selected independently from alkoxy groups having 1 to 6, especially 1 to 3, carbon atoms, such as propoxy, ethoxy and methoxy, preferably methoxy and ethoxy, and particularly preferably methoxy.

[0066] In one particular embodiment, all X groups are identical and selected from alkoxy groups having 1 to 6, especially 1 to 3, carbon atoms, such as propoxy, ethoxy, and methoxy, preferably methoxy and ethoxy, and particularly preferably methoxy.

[0067] Examples of crosslinking agents of general formula (III) are methyltrimethoxysilane, dimethyldimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, isobutyltrimethoxysilane, octyltrimethoxysilane, hexadecyltrimethoxysilane, vinyltrimethoxysilane, vinyltri(2-methoxyethoxy)silane, vinyldimethoxymethylsilane, phenyltrimethoxysilane, tetramethyl orthosilicate, 3-methacryloyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3 - Glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 2-aminoethyl-3-aminopropyltrimethoxysilane, (trimethoxysilyl)methyl-O-methylcarbamate, N-((trimethoxysilyl)methyl)methacrylamide, N-((trimethoxysilyl)methyl)cyclohexylamine, N,N'-(methoxy(methyl)silyldiyl)dibenzoamide and corresponding compounds, wherein all methoxy groups have been replaced by ethoxy or propoxy groups, i.e., for example, methyltriethoxysilane, etc.

[0068] In a preferred embodiment of the invention, all X groups are alkoxy groups, particularly preferably methoxy and / or ethoxy groups.

[0069] Based on the above description, the crosslinking agent V, especially the crosslinking agent V of general formula (III), can be wholly or partially hydrolyzed and can condense to form a siloxane. This condensed siloxane can be prepared from one or more different crosslinking agents of general formula (III), wherein at least one of the base crosslinking agents is a trialkoxysilane or a tetraalkoxysilane, and wherein the average degree of condensation of the siloxane is preferably at least 4. Therefore, the siloxane is preferably a condensation product of a monomeric alkoxysilane of general formula (III) containing an alkoxy group.

[0070] Monoalkoxysilanes, dialkoxysilanes, trialkoxysilanes, or tetraalkoxysilanes, or mixtures thereof, can be used for partial hydrolysis and condensation, wherein at least one alkoxysilane is a trialkoxysilane or a tetraalkoxysilane. The degree of condensation and the proportion of alkoxy groups retained in the formed siloxane can be adjusted depending on the alkoxysilane used and the reaction process, particularly the amount of water added, wherein the average degree of condensation of the siloxane is preferably at least 4. The siloxane can consist of straight chains and / or branches, rings, or cages. Those skilled in the art will appreciate that mixtures of such structural elements are commonly present. The alkoxysilane can have non-hydrolyzable groups bonded to silicon atoms, particularly monovalent hydrocarbon groups optionally having one or more functional groups, which are retained in the formed siloxane. Alcohols formed as byproducts can be removed, for example, by vacuum evaporation. Alkoxy-containing siloxanes formed therefrom are known and commercially available.

[0071] In addition, monoalkoxysilanes and / or dialkoxysilanes can be used to prepare alkoxy-containing siloxanes. Examples are trimethylmethoxysilane, triethylmethoxysilane, triphenylmethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, and diphenyldimethoxysilane, as well as the corresponding silanes in which all methoxy groups have been replaced by ethoxy or propoxy groups. Monoalkoxysilanes and / or dialkoxysilanes can be used, for example, to adjust the degree of condensation or the branching of the resulting siloxane.

[0072] Preferred trialkoxysilanes or tetraalkoxysilanes for preparing alkoxy-containing siloxanes are methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, tetraethoxysilane, tetramethoxysilane, and mixtures thereof.

[0073] In a preferred embodiment of the moisture-curing silicone composition, the crosslinking agent V is selected from alkyl-, alkenyl-, and aryltrimethoxysilanes, optionally other silanes and / or mixtures of these silanes. The crosslinking agent V selected from alkyl-, alkenyl-, and aryltrimethoxysilanes is preferably present in an amount of 0.1% to 2.5% by weight, preferably 0.5% to 2% by weight, based on the total composition.

[0074] In the same or other preferred embodiments of the moisture-curing silicone composition, the composition further contains a crosslinking agent V having an adhesion-promoting effect, preferably selected from tris[3-(trimethoxysilyl)propyl]isocyanurate, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and any mixture thereof, particularly in an amount of 0.1% to 5% by weight, preferably 0.5% to 4% by weight, based on the total composition.

[0075] Condensation catalyst K

[0076] Also included in the compositions of the present invention is at least one condensation catalyst K. This is used to catalyze the hydrolysis and condensation that occurs between a crosslinkable polydiorganosiloxane P and a crosslinking agent V in the presence of moisture or water.

[0077] The condensation catalyst K is a reaction product obtained by reacting 1 equivalent of a metal complex MC with 0.1 to 1 equivalent of (preferably partially esterified) phosphoric acid or organophosphonic acid PO, wherein the metal complex MC is a titanium (IV), zirconium (IV) or aluminum (III) complex having at least one alkoxy ligand and at least one organic chelate ligand, preferably a titanium (IV) complex.

[0078] Therefore, the metal complex MC is a titanate, zirconate, or aluminate.

[0079] Titanate esters or organotitanate esters are compounds having at least one ligand bonded to a titanium atom via an oxygen atom. The same definition applies to zirconate esters and aluminate esters, differing only in the metal atom.

[0080] The metal complex MC has at least one organic chelating ligand. The organic chelating ligand is a polydentate ligand containing carbon and a heteroatom. These are well known to those skilled in the art. There are no particular limitations on the type of organic chelating ligand on the metal complex MC. Their coordination number simply must be low enough that at least one alkoxy ligand is simultaneously complexed with the metal atom. Bidentate organic chelating ligands are preferred.

[0081] Suitable organic chelating ligands on metal complexes (MC) include, for example, acetylacetone (acac), ethylenediamine (en), diethylenetriamine (dien), iminodiacetic acid ester (ida), triethylenetetramine (trien), bis(salinyl)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(diphenylphosphine)ethane (dppe).

[0082] Chelating ligands that form complexes with metals via carbonyl oxygen atoms are preferred. Acetylacetone (acac) and ethyl acetoacetate (etac) are particularly preferred.

[0083] In a preferred embodiment, the metal complex MC comprises one or two chelate ligands, preferably acetylacetone ligand and / or ethyl acetoacetate ligand.

[0084] There are no particular restrictions on the alkoxy ligands on the metal complex MC. They are preferably C3-C8 alkoxy ligands, especially branched ligands. Particularly preferred alkoxy ligands are propoxy, isopropoxy, and isobutoxy ligands.

[0085] In a preferred embodiment, the metal complex MC contains one or two alkoxy ligands, preferably alkoxy ligands having 3 to 8 carbon atoms.

[0086] The metal complex MC can be a titanium (IV), zirconium (IV) or aluminum (III) complex, preferably a titanium (IV) complex.

[0087] The most preferred metal complexes MC are dialkoxybis(ethyl acetoacetate) titanates. They are particularly suitable for preparing condensation catalysts K and result in exceptionally good catalytic performance. Furthermore, they are widely available commercially. Suitable dialkoxybis(ethyl acetoacetate) titanates can be, for example, marketed under the trade name Tyzor. ® IBAY (Dorf Ketal), Tytan ® S3 (Borica) or Tytan ® S6 (Borica) obtained.

[0088] To prepare the condensation catalyst K, the metal complex MC is reacted with preferably partially esterified phosphoric acid or organophosphonic acid PO. Here, 1 molar equivalent of the metal complex MC is reacted with 0.1-1 molar equivalents of phosphoric acid or organophosphonic acid PO to form a complex of phosphoric acid or organophosphonic acid PO and the metal complex MC.

[0089] When 2 equivalents or more of phosphoric acid or organophosphonic acid (PO) are used, the resulting catalyst is completely deactivated, and the composition no longer hardens. Preferably, 0.25-0.75 equivalents, more preferably 0.4-0.6 equivalents, of partially esterified phosphoric acid or organophosphonic acid (PO) are used to react 1 equivalent of the metal complex (MC). These preferred ratios result in particularly advantageous performance in terms of the obtained mechanical properties and storage stability.

[0090] The complexation reaction of phosphoric acid or organophosphonic acid (PO) with metal complex (MC) can be achieved through... 31 P and 11H NMR spectral tracking. NMR measurements are known to those skilled in the art and can be performed routinely. The following examples relate to the complexation reaction on titanate esters. During the reaction, the free (uncomplexed) phosphate ester... 31 The P NMR signal gradually disappears (0.25 ppm for monoesters and 1.45 ppm for diesters). When these phosphate esters are complexed with titanium atoms, new NMR signals appear in the NMR spectrum of the reaction mixture. 31 The P NMR signal becomes visible at -10 ppm or -20 ppm. Meanwhile, in the reaction mixture... 1 Ligand exchange can occur in ¹H NMR spectra. The signal of the free P(=O)-OH group of the uncomplexed, partially esterified phosphate ester disappears at 10.9 ppm.

[0091] Partially esterified phosphoric acid or organophosphonic acid (PO) is preferably a phosphate diester or a monoester of an organophosphonic acid. However, it is important that at least one p-OH group is present in the phosphoric acid or organophosphonic acid (PO). In the latter case, the organic group is not particularly limited. It preferably includes a straight-chain or branched alkyl group having 3-12 carbon atoms.

[0092] Preferably, the phosphoric acid or organophosphonic acid PO has been partially esterified and is a dialkyl phosphate ester or a monoalkyl organophosphonic acid ester having exactly one P-OH group.

[0093] There are no particular limitations on alcohols esterified with partially esterified phosphoric acid or organophosphonic acid (PO). They are preferably C3-C12 alcohols, especially C6-C10 alcohols, which are preferably branched.

[0094] Suitable and preferred phosphoric acid or organophosphonic acid (PO) is commercially available, for example, as stabilizer POP. ® (Wacker), TIB STAB ® 115 (TIB Chemicals) or Lakeland ® TPA 800 (Lakeland Labs) was purchased commercially.

[0095] The moisture-curing silicone composition particularly contains a condensation catalyst K at a concentration between 1.0% and 3.0% by weight, preferably between 1.5% and 2.5% by weight, based on the total composition.

[0096] Optional other ingredients

[0097] The compositions of the present invention may optionally also contain other components commonly used in moisture-curing, condensation-crosslinking silicone compositions. These other components are, for example, fillers, plasticizers, adhesion promoters, curing promoters, OH scavengers, desiccants, wetting aids, rheology modifiers, thixotropic agents, processing aids, biocides, UV stabilizers, heat stabilizers, flame retardants, color pigments, flavor enhancers, antistatic agents, and / or emulsifiers.

[0098] The compositions of the present invention preferably contain at least one of these optional additional ingredients.

[0099] In a preferred embodiment of the moisture-curing silicone composition, the composition further contains at least one filler, particularly in an amount of 10% to 60% by weight, preferably 25% to 45% by weight, based on the total composition.

[0100] Fillers can affect, for example, the rheological properties of uncured compositions and the mechanical properties and surface characteristics of cured compositions. Using a variety of fillers in a composition may be advantageous.

[0101] Examples of suitable fillers are inorganic or organic fillers, such as naturally ground chalk or significantly dried precipitated chalk, both optionally surface-treated with fatty acids, for example; silica (silicon dioxide), especially pyrolytic silica, optionally surface-treated with silicone oil, for example; aluminum hydroxide such as aluminum trihydride, magnesium oxide and magnesium hydroxide; carbon black, especially industrial carbon black; barium sulfate; dolomite; silica; kaolin; hollow beads; quartz; calcined alumina; aluminum silicate; magnesium aluminum silicate; zirconium silicate; ground cristobalite; diatomaceous earth; mica; titanium oxide; zirconium oxide; gypsum; graphite; carbon fiber; zeolite; and glass fiber, whose surfaces are optionally treated with hydrophobic agents.

[0102] The preferred filler is ground, particularly uncoated calcium carbonate, especially in an amount of 10% to 60% by weight, preferably 25% to 45% by weight, based on the total composition.

[0103] The ground chalk can be coated or uncoated, preferably uncoated. Suitable coatings are known to those skilled in the art, including, for example, stearate coatings and silane coatings.

[0104] Suitable ground chalk is commercially available in large quantities, such as Omyacarb® products from Omya, for example, 1-AV or 5-AV; and Calcilit® and Calciplast® products from Alpha-Calcit.

[0105] Precipitated chalk is not preferred because it typically has a significant water content and must be laboriously dried to ensure adequate storage stability.

[0106] The ground chalk (calcium carbonate) used can be any commercially available chalk, wherein in a preferred embodiment, the ground chalk has a particle size d50 of 1 to 5 μm.

[0107] The particle size number, or the synonym d50 particle size, refers to 50% by weight of particles having a size less than or equal to the specified value.

[0108] The d50 particle size can typically be determined by laser scattering according to the standard ISO 13320:2009, for example using a CILAS 920 instrument from CILAS Corporation or a Malvern Mastersizer 3000 instrument from Malvern Panalytical Corporation.

[0109] Suitable ground chalk can be obtained from, for example, Provençale and Omya.

[0110] Depending on the production conditions, fillers, particularly ground chalk, generally have an advantageous low water content. Nevertheless, drying the fillers may be advantageous in terms of storage stability (especially in the case of RTV-1 compositions). An example of a suitable method for this purpose is vacuum treatment at elevated temperatures, for example at least 60°C, preferably 80°C to 100°C, or treatment at 120°C without vacuum for a longer period, such as 24 hours. The moisture content of the dried fillers is preferably < 0.2% by weight, particularly < 0.1% by weight, based on the total weight of the dried fillers.

[0111] The compositions of the present invention preferably do not contain any precipitated silica, as this may impair the storage stability of the compositions.

[0112] Conversely, pyrolytic silica is possible and preferred, without limitation. The addition of pyrolytic silica improves the stability and thixotropic properties of the composition.

[0113] Therefore, the moisture-curing silicone composition preferably contains additional pyrolytic silicon dioxide.

[0114] The pyrolytic silica is specifically contained in an amount of 0.5% to 10% by weight, preferably 1% to 5% by weight, based on the total composition.

[0115] Examples of plasticizers that may be used optionally are trialkylsilyl-terminated polydimethylsiloxanes, preferably having a viscosity of 1-10000 mPa·s at 23°C. For example, trimethylsilyl-terminated polydimethylsiloxanes may also be used, in which some methyl groups are substituted with other organic groups such as phenyl, vinyl, or trifluoropropyl groups. Polydimethylsiloxanes may also be monofunctional, i.e., reactive at one end, for example, via a hydroxyl terminal group. Certain hydrocarbons can also be used as plasticizers. Suitable hydrocarbons are commercially available, for example, under the trade name Hydroroseal G 232 H from Total Corporation.

[0116] Examples of optional adhesion promoters are silyl-containing compounds with hydrolyzable groups on the silicon atoms, particularly epoxysilanes such as 3-glycidoxypropyltrimethoxysilane. These silanes are classified as crosslinking agents of general formula (III) because they can participate in crosslinking reactions.

[0117] Combining two or more adhesion promoters may be advantageous.

[0118] The OH scavenger used is optionally a compound that reacts with any OH groups that may be present. OH groups may exist as uncapped chain ends of polydiorganosiloxanes, as OH groups on fillers, or as water. The OH scavenger can be a Si-N containing compound. Examples of OH scavengers are hexamethyldisilazane (HMDZ), hexamethylcyclotrisilazane, octamethyltetrasilazane, and bis(trimethylsilyl)urea. HMDZ is the most preferred OH scavenger.

[0119] All components of the moisture-curing condensation crosslinking composition can be mixed with each other in a conventional manner. For this purpose, the individual components are tightly mixed with each other in a suitable mixing device (e.g., a forced mixer, planetary mixer, mixing tube, kneader, dissolver, or extruder). The mixing can be carried out continuously or in batches. The crosslinkable polydiorganosiloxane P of the present invention, especially one of general formulas (I) or (Ia), can be prepared in an upstream spatially separated reaction, optionally with intermediate storage, and then metered into the mixing device in a suitable amount. Alternatively, and in some cases preferably, the crosslinkable polydiorganosiloxane P, especially one of general formulas (I) or (Ia), can also be prepared directly in the mixing device described above, and additional components are metered and mixed at the end of this preparation without post-treatment and / or intermediate storage of the polydiorganosiloxane P.

[0120] In a preferred embodiment, the composition of the present invention is a one-component composition cured by air moisture.

[0121] The compositions of the present invention can be used as adhesives or sealants in methods of bonding or joining substrates.

[0122] Therefore, one aspect of the present invention is a method of bonding or joining substrates.

[0123] The method of bonding or joining substrates using the present invention and the moisture-curing compositions described above includes:

[0124] a) Optionally, the components of the composition, which may be stored in different containers, are mixed to obtain a complete mixture of all the ingredients of the composition.

[0125] b) Applying the fully mixed composition to a substrate and attaching 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 bonding between the substrates, and

[0126] c) The composition thus applied hardens by the action of moisture, especially air humidity.

[0127] Therefore, the possible mixing in step a) can be performed before or during the application or introduction in step b). Mixing should be done relatively quickly before further processing, as the curing process begins with the mixing. Of course, step a) is omitted when using the RTV-1 formulation.

[0128] The application of the mixture to the substrate or the introduction of a joint between the substrates in step b) can be performed in a conventional manner, such as manually or automatically using a robot. During the bonding process, the substrate containing the mixture is brought into contact with another substrate, optionally under pressure, to achieve an adhesive bond between the substrates. The mixture is then cured in step c), typically at room temperature, to achieve bonding or joining of the substrates. In this way, the cured mixture is used as an adhesive or sealant material to obtain the bonded or joined substrates of the present invention.

[0129] The substrates to be bonded or joined can be the same material or different materials. Any conventional material can be bonded or joined using the two-component composition of the present invention. Preferred materials for bonding or joining are glass, metals such as aluminum, copper, steel or stainless steel, concrete, mortar, building stone such as sandstone and lime-sand brick, asphalt, tar, plastics such as polyolefins, PVC, Tedlar, PET, polyamide, polycarbonate, polystyrene or polyacrylate, and composite materials such as CFK.

[0130] Therefore, the two-component composition of the present invention can be used as an adhesive or sealant, for example in the following fields: construction, sanitation, automotive, solar technology, wind power technology, white goods, facade and window construction, electronic equipment, and shipbuilding.

[0131] Therefore, the present invention also provides the use of the compositions of the present invention according to the above description as adhesives, sealants, coatings or encapsulating compounds, particularly in the following fields: construction, sanitation, automobile construction and in-vehicle entertainment, solar energy, wind energy, white goods, facade and window construction, electronics, and shipbuilding.

[0132] Another aspect of the invention is an adhesive or bonded substrate that can be obtained according to the method described above.

[0133] Example

[0134] Specific embodiments of the present invention are described below, but are not intended to limit the scope of the invention. All tests were conducted at 23°C and 50% RH (relative humidity).

[0135] Weigh the components of the silicone compositions in the proportions given in Tables 3, 5, and 7 below, and mix them sequentially at 2000 rpm under reduced pressure for 20 seconds at 23°C and 50% relative humidity on a Hauschild SpeedMixer. All values ​​for the components in Tables 3, 5, and 7 represent the parts by weight (e.g., in grams) of the corresponding component added to the respective composition. Seal the resulting compositions in an airtight container and store them at 23°C for 24 hours, then test them. Artificially age some samples in a sealed container at 70°C for 7 days, then store them at 23°C for 24 hours, and then test them.

[0136] The Shore A hardness was measured on a Bareiss Shore A hardness tester after curing for 7 days according to DIN ISO 7619-1. For the Shore A hardness determination, circular specimens with a diameter of 42 mm and a thickness of 6 mm were prepared.

[0137] ISO 527 describes a method for determining elongation at break, tensile strength, and stress at 100% elongation, as well as the preparation of test specimens required for this purpose. Measurements were taken at a tensile rate of 200 mm / min on a type 1B test specimen (ISO 527-2) at 23°C and 50% relative humidity. For this purpose, the composition was pre-coated to obtain a skin layer of 2 mm thickness and cured for 7 days.

[0138] The method for determining tear resistance (“WRW”) and the preparation of the specimens required for this purpose are described in DIN ISO 34-1. The measurement is performed on a type C specimen.

[0139] To determine the crusting time (“HBZ”), the composition to be tested was applied to a surface of approximately 20 cm². 2The coating thickness is approximately 1 cm over an area. Ensure the surface is smooth. The coating time marks the start of the measurement. Touch the surface of the cured composition with a PE pipette. Obtain the skinning time when the PE pipette can be removed without any visible adhesion.

[0140] Viscosities were measured at 23°C using an MCR101 cone-plate viscometer from Anton Paar, Austria, according to DIN EN ISO 3219, with a CP 25-1 cone and a 0.049 mm pitch. Reported viscosity values ​​per 0.9 s. -1 The shear rate.

[0141] The abbreviations for 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 trading companies such as Sigma-Aldrich.

[0142]

[0143] Table 1: Ingredients used.

[0144] Preparation of condensation catalyst K

[0145] A series of condensation catalysts K were prepared by mixing and reacting titanate TI1 and phosphate PO1 in specified molar ratios at room temperature in each case. During this process, phosphate ester complexes were formed on the titanate ester, respectively. The reaction can be carried out by… 31 P and 1 The NMR spectrum is used for tracking. NMR measurements are known to those skilled in the art and can be performed routinely. During the reaction, the NMR spectrum of the reaction mixture of free (uncomplexed) phosphate esters... 31 The P NMR signal gradually disappeared (0.25 ppm for monoesters and 1.45 ppm for diesters). When these phosphate esters are complexed onto titanium atoms, the signal, especially at -10 ppm and -20 ppm, is significantly reduced. 31 It becomes visible in the p NMR spectrum.

[0146] At the same time, it can be in the reaction mixture 1 The complexation process was tracked in the 1H NMR spectrum. The signal of the free P(=O)-OH group of the uncomplexed, partially esterified phosphate ester disappeared at 10.9 ppm.

[0147] In the preparation of condensation catalyst K, the reaction proceeds until... 31 P NMR and 1¹H NMR spectroscopy showed that the phosphate ester used was completely complexed. The resulting condensation catalyst K was then used without further treatment. Table 2 shows the prepared condensation catalyst K and the amounts of titanate TI1 and phosphate PO1 used.

[0148]

[0149] Table 2: Catalyst K prepared. Not based on the present invention

[0150] In another experiment, titanate TI3 was complexed with phosphate PO1, corresponding to the preparation of catalyst K1. However, this formed an insoluble complex that was completely inactive in the formulations shown in Table 3. The composition subsequently did not solidify. This suggests that ligands that have a positive effect on solubility or miscibility in a silicone matrix, such as ethyl acetoacetate ligands on titanate TI, are advantageous.

[0151] The same situation can be further observed in Table 6 using titanate TI2. Although this titanate TI is a complex using phosphate ester PO ligand, ethyl acetoacetate ligand is also lacking here. This results in significantly worse storage stability compared to the experiments of this invention using catalyst K.

[0152]

[0153] Table 3: Formulation details and some measurement results for experiments E1 to E10. “n / m” indicates that no measurement was taken. Reference experiment not of this invention.

[0154]

[0155] Table 4: Measurement results after curing of experiments E1 to E10. “n / m” indicates that no measurement was taken. Reference experiment not of this invention.

[0156] The results in Table 4 show that the catalyst K1 of the present invention 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). Here, when testing and comparing freshly prepared and artificially aged materials, the compositions catalyzed according to the present invention exhibit smaller differences in these mechanical properties. In all embodiments, artificial aging was performed by storing the produced samples in a sealed container at 70°C for 7 days. This thermal storage allows for the determination of the storage stability of the compositions by simulating accelerated aging.

[0157] Of particular note is that the complexing catalyst K1 of the present invention results in higher storage stability (E2) than when titanate TI1 and esterified phosphoric acid PO1 (not in pre-complexed form) are added alone for this purpose. (Comparison with E3).

[0158]

[0159] Table 5: Formulation details and some measurement results for experiments E11 to E15. “n / m” indicates that no measurement was taken. This is a reference experiment not applicable to this invention. "n / h" indicates that the sample was not cured after 7 days under standard climatic conditions.

[0160]

[0161] Table 6: Measurement results after curing of experiments E11 to E15. “n / m” indicates that no measurement was taken. Reference experiments not applicable to this invention. “n / h” indicates that the composition did not cure after 7 days under standard climatic conditions and could not be measured.

[0162]

[0163] Table 7: Formulation details and some measurement results for experiments E16 ~ E20. Reference experiment not of this invention.

[0164]

[0165] Table 8: Measurement results after curing of experiments E16 ~ E20. Reference experiment not of this invention.

[0166] The results in Table 6 show that the catalyst K of the present invention prepared according to claim 1 results in very good storage stability (manifested as minimal change in mechanical properties after curing). Reference experiment E14, using a commercially available catalyst, showed a significant loss of mechanical properties after artificial aging of the uncured composition. Reference experiment E15 did not cure at all because the catalyst not prepared according to the present invention was completely inactive.

[0167] The results in Table 8 indicate that even with small amounts of phosphoric acid or organophosphonic acid (PO), the pre-reaction of the metal complex MC with phosphate or PO has a positive effect on storage stability. Optimal results are achieved when a mixing ratio of approximately 4:1 for the metal complex MC to phosphate or PO is reached. Increasing the concentration of phosphate or PO to a 2:1 ratio does not provide any further improvement, and in particular, leads to a longer crusting time (see Experiment E15 in Table 6).

Claims

1. A moisture-curing silicone composition comprising: a) At least one crosslinkable polydiorganosiloxane P having an alkoxysilane end group; b) At least one condensation catalyst K; c) At least one crosslinking agent V having an alkoxysilyl group; d) Optional other ingredients; Its features are, The condensation catalyst K is a reaction product obtained by reacting 1 equivalent of a metal complex MC with 0.1 to 1 equivalent of a preferably partially esterified phosphoric acid or organophosphonic acid PO, wherein the metal complex MC is a titanium (IV), zirconium (IV) or aluminum (III) complex, preferably a titanium (IV) complex, having at least one alkoxy ligand and at least one organic chelate ligand.

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

3. The moisture-cured silicone composition according to claim 1 or 2, characterized in that, The metal complex MC contains one or two chelate ligands, preferably acetylacetone ligands and / or ethyl acetoacetate ligands.

4. The moisture-curing silicone composition as described in any one of the preceding claims, characterized in that, The crosslinkable polydiorganosiloxane P is prepared by the condensation reaction of OH-terminated polydiorganosiloxane and trialkoxysilane or tetraalkoxysilane, preferably methyltrialkoxysilane, phenyltrialkoxysilane or vinyltrialkoxysilane.

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

6. The moisture-curing silicone composition as described in any one of the preceding claims, characterized in that, The crosslinking agent V is selected from alkyl-, alkenyl- and aryltrimethoxysilanes, optionally other silanes and / or mixtures of these silanes.

7. The moisture-curing silicone composition as described in any one of the preceding claims, characterized in that, The phosphoric acid or organophosphonic acid PO has been partially esterified and is a dialkyl phosphate ester or a monoalkyl organophosphonic acid ester having exactly one P-OH group.

8. The moisture-curing silicone composition as described in any one of the preceding claims, characterized in that, One equivalent of the metal complex MC is reacted using 0.25 to 0.75 equivalents, preferably 0.4 to 0.6 equivalents of the preferred partially esterified phosphoric acid or organophosphonic acid PO.

9. The moisture-curing silicone composition as described in any one of the preceding claims, characterized in that, The composition contains a condensation catalyst K at a concentration between 1.0 wt% and 3.0 wt%, preferably between 1.5 wt% and 2.5 wt%, based on the total composition.

10. The moisture-curing silicone composition as described in any one of the preceding claims, characterized in that, The composition further contains a crosslinking agent V having an adhesion promoting effect, the crosslinking agent preferably selected from tris[3-(trimethoxysilyl)propyl]isocyanurate, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane and any mixture thereof, particularly in an amount of 0.1% to 5% by weight, preferably 0.5% to 4% by weight, based on the total composition.

11. The moisture-curing silicone composition as described in any one of the preceding claims, characterized in that, The composition further contains at least one filler, preferably ground calcium carbonate, especially uncoated calcium carbonate, in particular in an amount of 10% to 60% by weight, preferably 25% to 45% by weight, based on the total composition.

12. The moisture-curing silicone composition as described in any one of the preceding claims, characterized in that, Other components include plasticizers, adhesion promoters, curing promoters, OH scavengers, desiccants, wetting agents, rheology modifiers, thixotropic agents, processing aids, biocides, UV stabilizers, heat stabilizers, flame retardants, color pigments, flavor enhancers, antistatic agents, and / or emulsifiers.

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

14. Use of the composition as an adhesive, sealant, coating or casting material as described in any of the preceding claims, particularly in the fields of: construction, sanitation, automobile construction and repair, solar technology, wind energy, white goods, facade and window construction, electronic equipment and shipbuilding.

15. A method for bonding or joining substrates using a moisture-curing composition as described in any one of claims 1-13, comprising: a) Optionally, the components of the composition, which may be stored in different containers, are mixed to obtain a complete mixture of all the ingredients of the composition. b) Applying the fully mixed composition to a substrate and bonding 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) The composition applied thereby is cured by the action of moisture, especially air moisture.

Images