Thermally initiated, acid-catalyzed reactions of silyl hydrides with silyl ethers and / or silanols.

Abstract

The composition comprises a silyl hydride, a silanol and / or a silyl ether, a Lewis acid catalyst, and a compound of the following formula: R 1 R 2 R 3 N [wherein the nitrogen is not a member of an N=CN bond, R 1 , R 2 , and R 3 wherein each of R is independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, and conjugated moieties; 1 , R 2 , and R 3 At least one of is a conjugated moiety connected to the nitrogen by a conjugated carbon.

Description

[Background technology]

[0001] FIELD OF THE INVENTION The present invention relates to a composition comprising a silyl hydride, a silyl ether and / or a silanol, a Lewis acid catalyst, and an amine blocking agent for the Lewis acid catalyst. Heating the composition releases the Lewis acid catalyst from the amine blocking agent, which can induce a reaction between the silyl hydride and the silyl ether and / or the silanol.

[0002] Introduction Strong Lewis acids are known catalysts for many reactions. For example, the Piers-Rubinsztajn (PR) reaction of silyl hydrides with silyl ethers is a well-known reaction catalyzed by strong Lewis acids, particularly tris(pentafluorophenyl)borane ("BCF"). Similar Lewis acid-catalyzed reactions include the rearrangement reaction of silyl hydrides with polysiloxanes and the rearrangement reaction of silyl hydrides with silanols. See, for example, Chem. Eur. J. 2018, 24, 8458-8469.

[0003] Lewis acid-catalyzed reactions, such as the PR reaction, tend to react rapidly, even at 23 degrees Celsius (°C). The high reactivity of these reaction systems limits their applications. While this reaction may be desirable in applications such as coatings and adhesives, the reaction system must be stored in a multi-component system to eliminate the reaction before application. Yet, as soon as the components are combined, the reaction can occur so rapidly that there is little time to apply the reaction system. It would be desirable to identify ways to control Lewis acid-catalyzed reactions, ideally providing them as a single-component system containing the reactants and Lewis acid catalyst in a form that is stable at 23°C but can be triggered to react as desired.

[0004] Ultraviolet (UV) photosensitive blocking agents are combined with Lewis acids to form blocked Lewis acids, which release the Lewis acid upon exposure to UV light. Upon exposure to UV light, the blocking agent dissociates from the Lewis acid, freeing it to catalyze the reaction. A challenge with systems containing these blocked Lewis acids is that they must be kept in the dark to maintain stability. Furthermore, exposure to UV light is required to initiate the reaction, and in thick compositions, it can be difficult to obtain UV light penetration throughout the composition to rapidly initiate cure.

[0005] In particular, amines have been attracting attention in combination with Lewis acids in PR reaction-type systems. However, amines have been reported to completely inhibit the reaction. See, e.g., Chem. Comm. 2010, 46, 4988-4990 at 4988. While most amines essentially irreversibly complex with Lewis acid catalysts, triarylamines proved to be an exception and were later identified as not impairing Lewis acids when catalyzing PR reactions. See, e.g., Chem. Eur. J. 2018, 24, 8458-8469 at 8461 and 8463. Summary of the Invention [Problem to be solved by the invention]

[0006] It is desirable to identify a method to prepare a one-part system for Lewis acid catalyzed reactions that is stable at 23° C. when exposed to UV light, yet can be triggered to react when desired.

[0007] The present invention provides a solution to the problem of identifying a method for preparing one-component systems for Lewis acid-catalyzed reactions that are stable at 23°C upon exposure to UV light, yet can be triggered to react when desired. In particular, the present invention provides a solution to such problems in the reaction of silyl hydrides with silanols and / or silyl ethers. Furthermore, the present invention provides such solutions that can be triggered to react upon heating to have desirable 90°C cure rates, i.e., 90°C cure rates of 15 minutes or less, preferably 10 minutes or less, more preferably 5 minutes or less, even more preferably 1 minute or less, and most preferably 30 seconds or less.

[0008] The present invention is the result of the surprising and unexpected discovery of certain amines that complex with Lewis acid catalysts at 23° C., block the activity of the Lewis acid catalyst, and form a stable one-component reaction system, but release the Lewis acid catalyst upon heating to effect rapid cure of the one-component reaction system. As a result, certain amines are thermally triggerable blockers for Lewis acid catalysts that block the Lewis acid catalyst at 23° C., but release the Lewis acid catalyst and catalyze reactions at elevated temperatures, such as above 80° C., above 90° C., or above 100° C. (and generally below 300° C., below 250° C., below 200° C., below 150° C., or even below 100° C.). This is surprising in light of previous understanding in the art. As noted above, the current understanding is that amines either irreversibly complex with or are unable to impair the Lewis acid catalyst in Lewis acid-catalyzed reactions. See Chem.Comm. 2010, 46, 4988-4990 at 4988 and Chem.Eur.J. 2018, 24, 8458-8469 at 8461 and 8463.

[0009] The present discovery of amines that act as thermally induced blocking agents for Lewis acid catalysts makes available compositions of the present invention that function as one-component reactive systems containing a Lewis acid catalyst, a silyl hydride, and a silanol and / or silyl ether, along with an amine blocking agent that is stable at 23°C but reacts upon heating.

[0010] In a first aspect, the present invention provides a compound comprising a silyl hydride, a silanol and / or a silyl ether, a Lewis acid catalyst, and a compound of the following formula: R 1 R 2 R 3 N [wherein the nitrogen is not a member of an N=CN bond, R 1 , R 2 , and R 3 wherein each of R is independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, and conjugated moieties. 1 , R 2 , and R 3 At least one of is a conjugated moiety connected to the nitrogen by a conjugated carbon.

[0011] In a second aspect, the invention is a process comprising: (a) providing a composition of the first aspect; and (b) heating the composition to a temperature sufficient to dissociate the Lewis acid catalyst from the amine.

[0012] The compositions of the present invention are suitable as one-component systems for coatings and adhesives, for example. DETAILED DESCRIPTION OF THE INVENTION

[0013] Test methods, unless a date is given with the test method number, refer to the most recent test method as of the priority date of this document. Reference to a test method includes both a reference to the testing institute and the test method number. The following test method abbreviations and identifiers apply herein: ASTM refers to ASTM International, EN refers to European Norm, DIN refers to Deutsches Institut fuer Normung, and ISO refers to the International Organization for Standardization.

[0014] "Plurality" means two or more. "And / or" means "and, or alternatively." All ranges are inclusive unless otherwise indicated. Products identified by trade names refer to compositions available from suppliers under those trade names as of the priority date of this document, unless otherwise stated herein.

[0015] The compositions of the present invention comprise a mixture of silanols and / or silyl ethers, silyl hydrides, Lewis acids, and amines. The compositions are useful as one-component reactive systems that are stable at 23°C but cure upon heating.

[0016] A "silanol" is a molecule containing a silicon-hydroxyl ("Si-OH") bond, and can contain multiple Si-OH bonds.

[0017] A "silyl ether" is a molecule that contains a silicon-oxygen-carbon ("Si-O-C") bond, and may contain multiple Si-O-C bonds.

[0018] A "silyl hydride" is a molecule that contains a silicon-hydrogen (Si-H) bond and can contain multiple Si-H bonds.

[0019] An "alkyl" is a hydrocarbon group derived from an alkane by removing a hydrogen atom. A "substituted alkyl" is an alkyl having an atom or chemical moiety other than carbon and hydrogen in place of at least one carbon or hydrogen.

[0020] An "aryl" is a group derived from an aromatic hydrocarbon by removing a hydrogen atom. A "substituted aryl" is an aryl that has an atom or chemical moiety other than carbon and hydrogen in place of at least one carbon or hydrogen.

[0021] "Conjugated" refers to a set of alternating carbon-carbon single and double and / or triple bonds whose p-orbitals are connected in a manner that allows delocalized electrons between the carbon bonds. "Conjugated carbon" refers to a set of alternating carbon-carbon single and double bonded carbons that are conjugated. "Non-conjugated" refers to a carbon that is not part of a conjugated system. "Aromatic" refers to a cyclic, planar, conjugated molecule.

[0022] A "blocking agent" is a component that binds to a second component to prevent the activity of the second component in some way. For example, a blocking agent on a catalyst will exclude the catalyst from catalytic activity and complex with the blocking agent.

[0023] Lewis acids catalyze the reaction of silyl hydrides with silanols, generally as shown below. Si-H + Si-OH + Lewis acid catalyst → Si-O-Si + H2 + Lewis acid catalyst

[0024] Lewis acids also catalyze the reaction of silyl hydrides with silyl ethers, as generally shown below: Si-H + Si-OR + Lewis acid catalyst → Si-O-Si + RH + Lewis acid catalyst wherein R is alkyl, substituted alkyl, aryl, or substituted aryl, provided that R has a carbon bonded to the indicated oxygen.

[0025] The present invention includes compositions comprising a mixture of a silyl hydride, a silyl ether and / or a silanol, a Lewis acid catalyst, and a specific amine. It has been discovered that the specific amine of the present invention acts as a blocking agent for the Lewis acid catalyst at 23°C but releases the Lewis acid catalyst at elevated temperatures (e.g., 80°C or higher or 90°C or higher). As a result, the compositions of the present invention are stable at 23°C but can be thermally induced to undergo Lewis acid-catalyzed reactions at elevated temperatures. Such compositions achieve the objective of the present invention of providing a "stable" one-component reaction system for Lewis acid-catalyzed reactions at 23°C. By "stable" at 23°C, it is meant that the reaction system does not gel at 23°C for 1 hour or less, preferably 3 hours or less, more preferably 6 hours or less, even more preferably 12 hours or less, and even more preferably 24 hours or less. Storage stability is evaluated using the "23°C Stability Test" in the Examples section below. The compositions of the present invention further provide a one-component reaction system for Lewis acid-catalyzed reactions that is stable at 23°C but can be thermally induced as desired. In particular, the compositions of the present invention cure in 30 minutes or less, preferably 10 minutes or less, more preferably 5 minutes or less, and even more preferably 1 minute or less at 90° C. The "Cure Rate at 90° C." test in the Examples section below is used to determine the cure rate at 90° C.

[0026] Silanol / Silyl Ether The present invention may include silanols without silyl ethers, silyl ethers without silanols, or both silanols and silyl ethers. When a composition includes both silanols and silyl ethers, the silanols may be different molecules from the silyl ethers, or the silanols and silyl ethers may be the same molecule with both Si-OH and Si-O-C bonds.

[0027] The silanols and silyl ethers for use in the present invention may be linear, branched, or a combination of linear and branched molecules. A branched molecule contains three or four "branches" from a single "branch" or "backbone" atom. A "branch" contains two atoms bonded to each other. Thus, a branched molecule contains one atom (the "backbone" atom) to which three or four atoms (first branch atoms) are bonded, each of which is further bonded to one more atom (second branch atom). The branches can extend for any number of atoms greater than two. Preferably, the branches in a branched molecule contain three or more, four or more, five or more, six or more, seven or more, eight or more, nine or more, and even ten or more atoms. At the same time, although there is technically no upper limit to the length of the branches in the branch atoms, branched silanols and silyl ethers for use in the present invention typically have 10,000 or less, preferably 5,000 or less, 1,000 or less, 500 or less, and can have 100 or less, 50 or less, 30 or less, 20 or less, and even 10 or less atoms in each branch.

[0028] The silanol of the present invention has a Si-OH bond. The silanol can have one or more Si-OH bonds. Any type of silanol is expected to be suitable. The silanol may be a hydroxylated silane or a hydroxylated siloxane. The silanol may be a siloxane having a degree of polymerization (DP) of 10 or more, preferably 20 or more, more preferably 30 or more, such as 40 or more, 50 or more, 75 or more, 100 or more, 250 or more, 500 or more, 1000 or more, 2,000 or more, 4,000 or more, 6,000 or more, and 8,000 or more, but at the same time, typically 10,000 or less, preferably 8,000 or less, 6,000 or less, 4,000 or less, 2,000 or less, 1,000 or less, 800 or less, 600 or less, 400 or less, 200 or less, or even 100 or less. DP corresponds to the number of siloxy (Si-O containing) groups present in the molecule and is determined by silicon-29 nuclear magnetic resonance ( 29 This can be determined by Si NMR spectroscopy.

[0029] The silyl ether of the present invention can have one or more Si-O-C bonds. Generally, any silyl ether is expected to be suitable. Typically, the silyl ether has a degree of polymerization (DP) of 10 or more, preferably 20 or more, more preferably 30 or more, and may be 40 or more, 50 or more, 75 or more, 100 or more, 250 or more, 500 or more, 1000 or more, 2,000 or more, 4,000 or more, 6,000 or more, and 8,000 or more, but at the same time, it is typically 10,000 or less, preferably 8,000 or less, 6,000 or less, 4,000 or less, 2,000 or less, 1,000 or less, 800 or less, 600 or less, 400 or less, 200 or less, or even 100 or less. DP corresponds to the number of siloxy groups present in the molecule, as determined by silicon-29 nuclear magnetic resonance ( 29 This can be determined by Si NMR spectroscopy.

[0030] The silanols and / or silyl ethers of the present invention may be polymeric. Desirably, the silanols and / or silyl ethers are polysiloxane molecules having one or more Si—OH and / or Si—OC bonds. The polysiloxane may be linear, with M(≡SiO 1 / 2 ) type and D(=SiO 2 / 2 Alternatively, the polysiloxane may be branched and contain only T(-SiO 3 / 2 ) and / or Q(SiO 4 / 2 ) type units. Typically, M, D, T, and Q units have a methyl group bonded to a silicon atom that does not have an oxygen bonded to it, providing a valence of four for each silicon, with each oxygen bonded to the silicon of another unit. When these are referred to as M, D, T, and Q "type" units, it is meant that a group such as one selected from the group consisting of hydrogen, alkyl, substituted alkyl, aryl, and substituted aryl groups can be bonded to the silicon atom in place of one or more methyls.

[0031] Examples of suitable silanols include those commercially available from The Dow Chemical Company as XIAMETER™ PMX-0156 silanol fluid, XIAMETER™ PMX-0930 silanol fluid, and DOWSIL™ DS polymer, DOWSIL™ RSN-217 Flake Resin, and DOWSIL™ RSN-233 Flake Resin, as well as those commercially available from Gelest as α,ω-hydroxyl-terminated poly(dimethylsiloxanes), DMS-S12 (550 g / mol, 16-32 cSt), DMS-S14 (1270 g / mol, 35-45 cSt), DMS-S31 (21,600 g / mol, 1000 cSt), and α,ω-hydride-terminated polyphenylmethylsiloxane (PMS-HO3, 340 g / mol, 2-5 cSt). XIAMETER is a trademark of Dow Corning Corporation. DOWSIL is a trademark of The Dow Chemical Company.

[0032] Examples of suitable silyl ethers include those sold under the following trade names: XIAMETER™ OFS-6070 silane, XIAMETER™ OFS-6011 silane, XIAMETER™ OFS-6020 silane, XIAMETER™ OFS-6030 silane, DOWSIL™ Z-6062 silane, DOWSIL™ Z-6300 silane, DOWSIL™ Z-6341 silane, XIAMETER™ OFS-6040 silane, DOWSIL™ Z-6023 silane, DOWSIL™ Z-6015 silane, XIAMETER™ OFS-6920 silane, XIAMETER™ OFS-6690 silane, and XIAMETER™ OFS-6076. silane, DOWSIL™ 3074 Intermediate, and DOWSIL™ 3037 Intermediate, available from The Dow Chemical Company. XIAMETER is a trademark of Dow Corning Corporation. DOWSIL is a trademark of The Dow Chemical Company.

[0033] Typically, the combined concentration of silanols and silyl ethers in the composition is 70 weight percent (wt%) or greater, 75 wt% or greater, 80 wt% or greater, 85 wt% or greater, or even 90 wt% or greater, based on the combined weight of silyl hydride, silanol, silyl ether, amine, and Lewis acid catalyst in the composition, while at the same time typically is 90 wt% or less, 85 wt% or less, 80 wt% or less, or even 75 wt% or less.

[0034] Silyl hydride Silyl hydrides contain one, preferably two or more, Si-H bonds. The Si-H bonds are typically part of polysilanes (molecules containing multiple Si-H bonds) or polysiloxanes. Silyl hydrides containing multiple Si-H bonds are desirable as crosslinkers in the compositions of the present invention because they can react with multiple silanol and / or silyl ether groups.

[0035] The silyl hydride may be the same molecule as the silanol and / or silyl ether, or may be a different molecule. That is, if the composition includes a silanol, the silanol may also contain a Si-H bond and function as both the silanol and silyl hydride components of the composition. Similarly, if the composition includes a silyl ether, the silyl ether may also contain a Si-H bond and function as both the silyl ether and silyl hydride components of the composition. Alternatively, the silyl hydride component may be a different molecule from the silanol and / or silyl ether also present in the composition. The silanol and / or silyl ether may not contain a Si-H bond.

[0036] The silyl hydrides of the present invention may be polymeric. They may be linear, branched, or contain a combination of linear and branched silyl hydrides. They may also be polysilanes, polysiloxanes, or combinations of polysilanes and polysiloxanes.

[0037] Desirably, the silyl hydride is a polysiloxane molecule having one Si-H bond or two or more Si-H bonds. The polysiloxane may be linear and contain only M and D units. Alternatively, the polysiloxane may be branched and contain T and / or Q units.

[0038] Examples of suitable silyl hydrides include pentamethyldisiloxane, bis(trimethylsiloxy)methyl-silane, tetramethyldisiloxane, tetramethylcyclotetrasiloxane, and hydride-terminated poly(dimethylsiloxane), such as those available from Gelest under the trade names DMS-H03, DMS-H25, DMS-H31, and DMS-H41.

[0039] The concentration of silyl hydride is typically sufficient to provide a molar ratio of Si—H groups to combined silanol and silyl ether groups that is 0.2 or more, 0.5 or more, 0.7 or more, 0.8 or more, 0.9 or more, 1.0 or more, 1.2 or more, 1.4 or more, 1.6 or more, 1.8 or more, 2.0 or more, 2.2 or more, or even 2.5 or more, while simultaneously typically 5.0 or less, 4.5 or less, 4.0 or less, 3.5 or less, 3.0 or less, 2.8 or less, 2.5 or less, 2.3 or less, 2.0 or less, 1.8 or less, 1.6 or less, 1.4 or less, 1.2 or less, or even 1.0 or less.

[0040] Either the silanol / silyl ether or the silyl hydride (or both) can function as a crosslinker in the reaction. A crosslinker has at least two reactive groups per molecule and reacts with two different molecules via these reactive groups to crosslink them together. Increasing the length of the linear chain between the reactive groups in the crosslinker tends to increase the flexibility of the resulting crosslinked product. In contrast, shortening the length of the linear chain between the reactive groups in the crosslinker tends to decrease the flexibility of the resulting crosslinked product. Generally, to obtain a more flexible crosslinked product, a linear crosslinker is desired, and the length between the reactive sites is selected to obtain the desired flexibility. To obtain a less flexible crosslinked product, a shorter linear crosslinker or even a branched crosslinker is desired to reduce the flexibility between the crosslinked molecules.

[0041] Typically, the concentration of silyl hydride in the composition is 5% by weight or more, 10% by weight or more, 15% by weight or more, 20% by weight or more, or even 25% by weight or more, based on the combined weight of silyl hydride, silanol, silyl ether, amine, and Lewis acid catalyst in the composition, while at the same time typically is 30% by weight or less, 25% by weight or less, 20% by weight or less, 15% by weight or less, or even 5% by weight or less.

[0042] Lewis acid catalyst The Lewis acid catalyst is preferably selected from the group consisting of aluminum alkyls, aluminum aryls, arylboranes, arylboranes including triarylboranes (including substituted aryl and triarylboranes such as tris(pentafluorophenyl)borane), boron halides, aluminum halides, gallium alkyls, gallium aryls, gallium halides, silium cations, and phosphonium cations. Examples of suitable aluminum alkyls include trimethylaluminum and triethylaluminum. Examples of suitable aluminum aryls include triphenylaluminum and tris-pentafluorophenylaluminum. Examples of triarylboranes include the following formula: [ka] where R, at each occurrence, is independently selected from H, F, Cl, and CF. Examples of suitable boron halides include (CH3CH2)2BCl and boron trifluoride. Examples of suitable aluminum halides include aluminum trichloride. An example of a suitable gallium alkyl includes trimethylgallium. An example of a suitable gallium aryl includes tetraphenylgallium. An example of a suitable gallium halides includes trichlorogallium. An example of a suitable silium cation includes (CH3CH2)3Si + X - and Ph3Si + X - Examples of suitable phosphonium cations include FP(C6F5)3 + X - Examples include:

[0043] The Lewis acid is typically present in the composition at a concentration of 10 parts per million (ppm) or more by weight, based on the combined weight of the silyl hydride, silanol, and silyl ether in the composition, such as 10 or more, 50 or more, 150 or more, 200 or more, 250 or more, 300 or more, 350 or more, 400 or more, 450 or more, 500 or more, 550 or more, 600 or more, 70 or more, 750 or more, 1000 or more, 1500 or more, 2000 or more, 4000 or more, 5000 or more, or even 7500 ppm or more, while also typically not more than 10,000, 7500 ppm or less, 5000 ppm or less, 1500 ppm or less, 1000 ppm or less, or 750 ppm or less.

[0044] amine The choice of amine is important because it must complex with the Lewis acid at 23°C, inhibiting the catalytic activity of the Lewis acid in the reaction composition at that temperature, and release the Lewis acid at such a high temperature that the reaction composition gels rapidly (within 10 minutes, preferably within 5 minutes, and more preferably within 1 minute) at 90°C. The reaction composition can be monitored at 23°C and 90°C to determine gel time (see the Examples section below). Alternatively, or additionally, the temperature at which the curing reaction exotherm occurs can be characterized by differential scanning calorimetry (Tpeak, see the Examples section below for procedures). The Tpeak value of a composition in the presence of a suitable amine should increase relative to the Tpeak of an identical amine-free composition, but desirably remain below 130°C, preferably below 120°C, and more preferably below 110°C, to reflect sufficient dissociation to cure rapidly at 90°C.

[0045] Amines are reported to irreversibly complex with Lewis acid catalysts, with the exception of triarylamines, which are reported not to harm the Lewis acid catalyst. Without being bound by theory, the present invention appears to result, in part, from the discovery that having one or more conjugated moieties attached to the amine nitrogen through a conjugated carbon helps delocalize the amine's free electrons, weakening it as a Lewis base. Consequently, it has been discovered that amines having at least one conjugated moiety attached to the amine nitrogen through a conjugated carbon complex with and block the Lewis acid catalyst at 23°C in a manner that impairs gelation of the reaction composition in 4 hours or less, preferably 8 hours or less, more preferably 10 hours or less, and even more preferably less than 12 hours at 23°C, yet simultaneously complex weakly enough to release the Lewis acid catalyst and gel the composition in 10 minutes or less, preferably 5 minutes or less, and more preferably 1 minute or less, when heated at 90°C.

[0046] To be sufficiently weak Lewis bases, the amines of the present invention have at least one, preferably at least two, and optionally three conjugated moieties attached to the nitrogen of the amine through a conjugated carbon such that the free electron pair on the nitrogen can dissociate from the conjugated moiety, weakening the amine as a Lewis base. Preferably, the conjugated moiety is an aromatic moiety.

[0047] Triarylamines have three conjugated aromatic moieties, each attached to the amine nitrogen through a conjugated carbon. As a result, triarylamines are examples of amines that optimally delocalize nitrogen free electrons to form weak Lewis bases. This is consistent with prior art reporting that triarylamines do not impair Lewis acid catalysis. Nevertheless, triarylamines have surprisingly been found to have a blocking effect on Lewis acid catalysis at 23°C, inhibiting Lewis acid-catalyzed reactions at 23°C, within the broadest range of amines suitable for use in the present invention. Desirably, the amines of the present invention are stronger Lewis bases than triarylamines to achieve a greater blocking effect at 23°C (and thus longer storage stability). In that regard, the amines of the present invention may have one, two, or three conjugated moieties attached to the amine nitrogen through a conjugated carbon, but desirably the amine is other than a triarylamine. The compositions of the present invention may be free of triarylamines.

[0048] The ability of the conjugated moiety to weaken the strength of the amine as a Lewis base can be further tuned with substituents that can be attached to the conjugated moiety. Inclusion of an electron-withdrawing group (such as a halogen) on the conjugated moiety further draws the nitrogen electron into the delocalized conjugated system, weakening the strength of the amine as a Lewis base. Inclusion of an electron-donating group on the conjugated moiety has the opposite effect, increasing the strength of the resulting amine as a Lewis base compared to the same amine with a conjugated moiety without the electron-donating group.

[0049] To achieve storage stability, the amine must be strong enough to bind and block the Lewis acid catalyst at 23° C. If the amine is a weak Lewis base, it will release the acid at a lower temperature than if it is a strong Lewis base. Thus, the choice of moiety attached to the amine nitrogen may be selected to achieve storage stability and reactivity at the desired temperature.

[0050] It has further been discovered that suitable amines must have an amine nitrogen that is not a member of an N=CN bond, such as amidine, guanidine, and N-methylimidazole. Desirably, the composition does not contain amines with N=CN bonds. For example, the composition may be free of amidines and guanidines.

[0051] Generally, the amine has the following formula: 1 R 2 R 3 N [wherein the nitrogen is not a member of an N=CN bond, R 1 , R 2 , and R 3 each of which is independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, and a conjugated moiety; 1 , R 2 , and R 3 At least one of R is a conjugated moiety connected to the nitrogen by a conjugated carbon. 1 , R 2 , and R 3 may be conjugated moieties connected to the nitrogen by conjugated carbons. Desirably, the conjugated moieties are aromatic moieties.

[0052] Examples of amines suitable for use in the present invention include any one amine or any combination of two or more amines selected from the group consisting of aniline, 4-methylaniline, 4-fluoroaniline, 2-chloro-4-fluoroaniline, diphenylamine, diphenylmethylamine, triphenylamine, 1-naphthylamine, 2-naphthylamine, 1-aminoanthracene, 2-aminoanthracene, 9-aminoanthracene, β-aminostyrene, 1,3,5-hexatriene-1-amine, N,N-dimethyl-1,3,5-hexatriene-1-amine, 3-amino-2-propenal, and 4-amino-3-buten-2-one.

[0053] The concentration of the amine in the composition is at least molar equivalent to the concentration of the Lewis acid catalyst so as to be able to complex and sequester all of the Lewis acid catalyst at 23° C. The concentration of the amine may exceed the molar concentration of the Lewis acid catalyst, but is preferably present at a concentration of 110 mole percent (mol%) or less, preferably 105 mol% or less, more preferably 103 mol% or less, and most preferably 101 mol% or less, based on the total moles of Lewis acid catalyst, but may be present at 100 mol% or more.

[0054] The amine and Lewis acid form a complex in the composition that sufficiently shields the Lewis acid from catalyzing reactions with other composition components, making it storage stable at 23° C. Upon heating, the amine releases the Lewis acid, allowing it to catalyze reactions.

[0055] Optional Ingredients The compositions of the present invention can consist of a silyl hydride, an α-β unsaturated ester, a Lewis acid catalyst, and an amine. Alternatively, the compositions of the present invention can further comprise one optional ingredient or a combination of two or more optional ingredients. The optional ingredients are desirably present in a concentration of 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, or even 1% by weight or less, based on the weight of the composition.

[0056] Examples of possible optional components include one or a combination of two or more components selected from the group consisting of hydrocarbyl solvents (typically at a concentration of 10% by weight or less, 5% by weight or less, or even 1% by weight or less, based on the weight of the composition), pigments such as carbon black or titanium dioxide, fillers such as metal oxides including SiO (typically at a concentration of 50% by weight or less, based on the weight of the composition), moisture scavengers, optical brighteners, stabilizers (such as antioxidants and UV stabilizers), and corrosion inhibitors. The compositions of the present invention may also be free of one or a combination of two or more of such additional components.

[0057] In particular, the compositions of the present invention may contain up to 1% by weight of water, up to 0.5% by weight of water, based on the weight of the composition. Desirably, the compositions are free of water.

[0058] Reaction Process The present invention includes a chemical reaction process comprising the steps of: (a) providing a composition of the present invention; and (b) heating the composition to a temperature sufficient to dissociate the Lewis acid catalyst from the amine.

[0059] Step (a) may include mixing together an amine, a Lewis acid catalyst, a silyl hydride, and a silanol and / or silyl ether. However, the Lewis acid catalyst and amine are combined such that the amine can complex and block the catalytic activity of the Lewis acid before combining with both the silyl hydride and the silanol and / or silyl ether. If the Lewis acid does not catalyze the reaction with one of the reactants, it is possible to prepare the Lewis acid / amine complex in the presence of one of the reactants (i.e., the silyl hydride or the silanol and / or silyl ether). The amine and Lewis acid may be combined in a solvent such as toluene to form a blocked Lewis acid complex, which may then be combined with the silyl hydride and the silanol and / or silyl ether.

[0060] Step (b) generally requires heating the composition to a temperature of 80°C or higher, preferably 90°C or higher, but may also be achieved by heating to a temperature generally not higher than 300°C, not higher than 250°C, not higher than 200°C, not higher than 150°C, or even not higher than 100°C.

[0061] The compositions of the present invention are particularly useful as coatings. They can also be useful in forming shaped articles. In such applications, the process of the present invention can further include applying the composition to a substrate after step (a) and before or during step (b). [Example]

[0062] The following Examples (Ex) and Comparative Examples (Comp Ex) A are made according to the following procedures using the amine blocking agents specified in Table 1. Table 1 also specifies the shelf life and cure rate at 90°C for the Examples and Comparative Examples. The shelf life and cure rate test methods are described below. Methods include making silyl hydride, silanol, and catalyst solutions according to the preparation procedures for the Comparative Examples and Examples below.

[0063] Preparation of Examples and Comparative Examples. 90 weight percent (wt%) MD in dental cup H 65 M silyl hydride at 10% by weight OH D5M OH Combine with silanol and mix in a SpeedMixer to form a reaction mixture, in weight percent based on the reaction mixture weight. In a separate container, prepare a catalyst solution (see below). Add enough catalyst solution to the reaction mixture to obtain 500 parts by weight of Lewis acid catalyst per million parts by weight of reaction mixture, and mix the resulting composition to form an example or comparative example. Characterize the 23°C shelf life and cure rate at 90°C.

[0064] MD H 65 M Silylhydride. Equip a three-neck flask with a mechanical stirrer and add 40 grams (g) of deionized water, 10 g of heptane, and 0.05 g of tosylic acid. Add a mixture of 200 g of methyldichlorosilane and 10 g of trimethylchlorosilane dropwise over 30 minutes with stirring. Stir for an additional 60 minutes at 23°C. Wash the reaction solution three times with 50 milliliters (mL) of deionized water. Dry the solution with anhydrous sodium sulfate and filter through activated carbon. Remove volatiles using a rotary evaporator (Rotovap) to obtain MD H 65 M silyl hydride is obtained.

[0065] M OH D5M OH Silanol. This material is commercially available from Gelest as DMS-S12.

[0066] Catalyst solution. For Example 1, 1.256 g of a 5 wt% solution of 4-methylaniline in toluene was added to 6 g of a 5 wt% solution of BCF in toluene in a 20 mL vial ([4-methylaniline] / [BCF] = 1:1 molar ratio). The mixture was sonicated for 30 seconds at 23 °C. The solution contained 4.12 wt% BCF and was used as the catalyst solution to prepare Example 1.

[0067] For the remaining compositions, a total of 12 grams of mixed solution was prepared by adding a 5 wt. % solution of aniline in toluene to a 5 wt. % solution of BCF in toluene in a 20 mL vial, containing a 1:1 ratio of [amine] / [BCF], followed by 30 seconds of sonication and then allowing to stand overnight in a hood. 0.5 to 1 gram of tetrahydrofuran was added to the solution to help dissolve the formed BCF-aniline complex. The clear solutions thus prepared were catalyst solutions for the compositions other than Example 1.

[0068] 23°C Stability Test. The composition is prepared in a vial, which is then sealed and stored at 23°C. The flowability of the vial contents is confirmed by inverting the vial and observing the contents to determine if they are flowing. Flowability is confirmed at 1-hour intervals, 8 hours, and after 24-hour intervals. The time at which gelation occurs, as evidenced by the vial contents no longer flowing within 1-2 seconds upon inversion, is recorded. The time at which gelation occurs is the "23°C shelf life." The composition is exposed to ambient (including ultraviolet) light during testing.

[0069] Cure Rate at 90°C. The cure rate at 90°C is the time it takes to form a tack-free gel or cured film on a surface at 90°C. Coat a 125 micrometer film of the composition onto a glassine paper substrate. Place the film in a 90°C oven. Check the film for tack every 30 seconds. The time required to achieve a tack-free film is the cure rate at 90°C.

[0070] Tpeak. Tpeak is the temperature at which the maximum exothermic reaction occurs in a reaction system. Tpeak is determined by differential scanning calorimetry (DSC) of a sample composition. A 10-milligram sample of the composition is characterized by DSC by loading it into a DSC pan and running the DSC at a rate of 10°C per minute using a temperature ramp from 10°C to 250°C. Tpeak is the temperature at which the maximum exothermic heat is evident in the DSC curve.

[0071] [Table 1]

[0072] The data in Table 1 reveal that when BCF is used without inhibition, Comparative Example A results in a reaction system that is not stable at 23°C. Comparative Examples B-E reveal that amines that do not have an aromatic carbon attached to the nitrogen (and / or have an N=CN bond) complex so strongly with BCF that they are unable to cure even after 60 minutes at 90°C. However, Examples 1-6 reveal that when one or more conjugated carbons are attached to the nitrogen, the amines provide adequate 23°C shelf life but also complex with BCF long enough to provide very rapid cure at 90°C.

[0073] Similar results are expected for compositions containing silyl ethers in place of silanol moieties.

Claims

1. a compound having one or more silyl hydride groups (Si—H); a compound having one or more silanol groups (Si—OH) and / or one or more silyl ether groups (Si—O—C), and a Lewis acid catalyst and a compound of the following formula: １ R ２ R ３ N [wherein the nitrogen is not a member of an N=C—N bond and is １ , R ２ , and R ３ each independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, and a conjugated moiety. A composition comprising: R １ , R ２ , and R ３ is a conjugated moiety attached to the nitrogen by a conjugated carbon; The composition, wherein the conjugated moiety is an aromatic moiety.

2. 2. The composition of claim 1, wherein the Lewis acid catalyst is selected from the group consisting of aluminum alkyls, aluminum aryls, aryl boranes, fluorinated aryl boranes, boron halides, aluminum halides, gallium alkyls, gallium aryls, gallium halides, silium cations, and phosphonium cations.

3. The composition of claim 2 wherein the Lewis acid catalyst is a fluorinated arylborane.

4. A compound having both (i) one or more silyl hydride groups and (ii) one or more silanol groups and / or one or more silyl ether groups, and A complex formed from a Lewis acid catalyst and an amine having the formula: R 1 R 2 R 3 N, wherein the nitrogen is not a member of an N═C—N bond, and each of R 1 , R 2 , and R 3 is independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, and a conjugated moiety. A composition comprising: one or two of R 1 , R 2 , and R 3 are conjugated moieties attached to the nitrogen by a conjugated carbon; The composition, wherein the conjugated moiety is an aromatic moiety.

5. The composition of any one of claims 1 to 4, wherein the composition does not include a UV photosensitive blocker for the Lewis acid catalyst.

6. (a) providing a composition according to any one of claims 1 to 5; (b) heating said composition to a temperature sufficient to dissociate said Lewis acid catalyst from said amine.

7. Step (a) mixing an amine, a Lewis acid catalyst, the compound having one or more silyl hydride groups, and the compound having one or more silanol groups and / or one or more silyl ether groups, or mixing an amine, a Lewis acid catalyst, and a compound having both (i) one or more silyl hydride groups and (ii) one or more silanol groups and / or one or more silyl ether groups; wherein the Lewis acid catalyst and the amine are both the compound having one or more silyl hydride groups and the compound having one or more silanol groups and / or one or more silyl ether groups, or - a compound having both (i) one or more silyl hydride groups and (ii) one or more silanol groups and / or one or more silyl ether groups 7. The process of claim 6, provided that, prior to being combined with said amine, said amine is combined with said Lewis acid such that said amine can complex with said Lewis acid to block the catalytic activity of said Lewis acid.

8. 8. The process of claim 6 or claim 7, wherein the process further comprises, after step (a) and before or during step (b), applying the composition to a substrate or placing the composition in a mold.

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