Silicone formulations comprising an oxime crosslinker, cured silicone formulations, and uses thereof

Abstract

The present invention relates to silicone formulations comprising an oxime silane crosslinker comprising 5-methyl-3-heptanone oxime. The silicone formulations of the present invention exhibit significantly improved early cracking behavior and / or skinning times compared to silicone formulations using conventional oxime silane crosslinkers. The present invention relates to the corresponding cured silicone formulations, the use of cured silicone formulations and the use of such oxime crosslinkers in the field of silicone formulations. The present invention also relates to oxime crosslinkers.

Description

TECHNICAL FIELD

[0001] The present invention relates to organosilicon formulations comprising an oxime crosslinker, the corresponding cured organosilicon formulations, the use of the cured organosilicon formulations, and the use of the oxime crosslinker in the field of organosilicon formulations. The present invention further relates to oxime crosslinkers. BACKGROUND

[0002] Room temperature vulcanizable compositions comprising polydiorganosiloxanes (also known as RTV silicones) are well known and used in a variety of applications. The most prominent use is in the construction sector, where RTV silicones are used as sealants, adhesives or coatings. Such silicones typically comprise a polydiorganosiloxane having reactive hydroxyl end groups as the base polymer, and incorporate a crosslinker and optional components (e.g. catalysts, fillers, pigments, dyes, lubricants, plasticizers, adhesion promoters, thickeners, etc.). Depending on the reactivity of the components and the desired shelf life, RTV silicones can be formulated as one-component (where all ingredients are blended), or as multi-component formulations (where different components contain different (parts) of the ingredients, which need to be mixed before use). The most commonly used silicone formulations are one-component (RTV1) or two-component (RTV2) formulations, which are typically moisture-curable, and use a tri- or tetra-functional silane (or their corresponding siloxane condensation products) as the crosslinker.

[0003] Ready-to-use moisture-curable silicones are traditionally sold and used with polydiorganosiloxanes and silane crosslinkers, which are pre-condensed in the form of so-called “prepolymers” or “end-capped” polysiloxanes. In the production of these moisture-curable silicones, the terminal hydroxyl groups of the polydiorganosiloxane are reacted with a tri- or tetra-functional silane (or its corresponding siloxane condensation products) crosslinker to form so-called “prepolymers”, which are then capable of curing by crosslinking under the influence of atmospheric moisture. This first reaction step is also called “end-capping”, i.e. the addition of a different end group on the reactive polydiorganosiloxane, and the resulting product can therefore also be called an “end-capped polymer”. Because this step leads to the formation of a “prepolymer”, i.e. a compound which is suitable for further polymerization, this reaction step is also commonly called “pre-polymerization”. This step prepares the reactive polymer for the subsequent polymerization reaction, which step itself is not a polymerization reaction.

[0004] Next, after the capped polysiloxane is extracted from its container (e.g., upon application of the silicone to the desired substrate), wet-cure takes place. The capped polymer has two (if the silane crosslinker is trifunctional) or three (if the silane crosslinker is tetrafunctional) remaining reactive groups. Without wishing to be bound by any theory, it is believed that after application of the silicone paste, moisture from the environment hydrolyzes these remaining reactive groups into more reactive silanol groups, which in turn form crosslinks with other capped polymer chains. Since the crosslinker has brought two or three reactive groups to each end of the original polydiorganosiloxane, a three-dimensionally crosslinked final structure can be formed in this way.

[0005] Based on the leaving group that is released during the hydrolysis, commonly used silane crosslinkers are either acidic (e.g., ethyl-tris(acetyloxy)silane) or neutral crosslinking (e.g., methyl-tris(methyl ethyl ketoximino)silane). Acidic crosslinkers have historically been the most important. However, due to the potential for the acid released during the crosslinking process to cause substrate degradation, poor adhesion to substrates, and often strong and unpleasant odors, there is an increasing development of systems based on neutral crosslinkers (e.g., oxime silanes).

[0006] The most abundant and economically successful oxime silane crosslinkers use methyl ethyl ketoxime (MEKO). However, RTV silicones using MEKO or similar oxime-based silane crosslinkers have a number of disadvantages. For example, many known oxime crosslinkers are either solids or highly viscous at room temperature, or are prone to forming solid particles due to crystallization of the oxime leaving group, which complicates the manufacture of the silicone formulation. Importantly, some oxime crosslinker hydrolysis products, such as 2-butanone oxime (produced by the hydrolysis of MEKO-capped siloxanes during the curing process), are associated with carcinogenic effects.

[0007] In order to function in practice, particularly as a sealant or grouting compound, an RTV silicone formulation needs not only to have desirable post-cure physical properties, but also to be “workable”, e.g., to have an appropriate skinning time and to exhibit low or preferably no early cracking behavior.

[0008] The skinning time of a silicone formulation is referred to as the time from the start of application to the surface to set (“skin”) and characterizes the time after which the sealant can be manipulated after application (e.g., extrusion from a container). A sufficiently long skinning time is important because in practice the sealant is first applied to a joint, and subsequently needs to be “smoothed out” using a finger dipped in a cleaning agent or a specific tool.

[0009] Early cracking behavior is referred to as the ability of a sealant to withstand deformation in its early stages of curing (incapacitation). Typically, sealants with poor early cracking behavior tend to crack at the joint soon after the sealant is applied when the joint is deformed. This can occur in practice when the joint material has a high or different coefficient of thermal expansion, in case of temperature changes of the joint, or due to (human) handling of the joint shortly after the sealant is applied, for example a person simply stepping in and out of a bath tub which is being sealed can already cause the joint to move several millimeters.

[0010] As shown in the appended examples, the present inventors have found that silicone formulations using known oxime-based silane crosslinkers exhibit short skin times and / or large early cracking windows.

[0011] Thus, there is a need for crosslinkers that can be used in RTV silicone formulations, especially sealant formulations, to overcome one or more of the problems of the prior art.

[0012] It is an object of the present application to provide a silane crosslinker and / or a silicone formulation comprising the same, which is characterized by, for example, an increased skin time and / or a reduced early cracking time compared to known oxime-based silane crosslinkers.

[0013] It is a further object of the present application to provide a silane crosslinker and / or a silicone formulation comprising the same, which has a reduced release of carcinogenic compounds and preferably leads to a reduction in the intensity and / or time of malodour upon curing compared to known oxime-based silane crosslinkers. SUMMARY

[0014] As shown in the appended examples, the present inventors have surprisingly found that silicone formulations using oxime silane crosslinkers comprising 5-methyl-3-heptanone oxime exhibit significantly improved early cracking behavior and / or skin times compared to silicone formulations using conventional oxime silane crosslinkers. Furthermore, the 5-methyl-3-heptanone oxime released during the moisture cure of the silicone formulation has low volatility and can have reduced or no carcinogenic effect and / or malodour compared to known oxime silane crosslinkers, such as MEKO silane.

[0015] The present inventors have also found that improved early cracking behavior and / or skin times can be achieved by using said oxime as their tri- or tetra-functional silane, tris(5-methyl-3-heptanone oximato)silane or tetra(5-methyl-3-heptanone oximato)silane, and when using 5-methyl-3-heptanone oxime as the free oxime in combination with any silane or siloxane crosslinker. Without wishing to be bound by any theory, the present inventors believe that the combination of 5-methyl-3-heptanone oxime as the free oxime with any silane or siloxane crosslinker leads to the in situ formation of 5-methyl-3-heptanone oximato silane.

[0016] Accordingly, in a first aspect, the present application provides an organosilicon formulation comprising a hydroxy-terminated polydiorganosiloxane and a first crosslinker selected from silanes according to formula (I) and hydrolysis or condensation products thereof:

[0017]

[0018] in which:

[0019] a is 0, 1, 2 or 3;

[0020] b is 0 or 1 ;

[0021] c is 1, 2, 3 or 4;

[0022] a + b + c is 4;

[0023] each occurrence of R 1 and R 2 is individually selected from hydrogen and an optionally substituted monovalent hydrocarbon group having 1 to 30 carbon atoms;

[0024] R 3 and R 4 each occurrence of R 3 is methyl and R 4 is hydrogen.

[0025] Based on the present disclosure, the skilled person will understand that the compound according to formula (I) is an oxime silane crosslinker comprising at least one 5-methyl-3-heptanone oxime moiety.

[0026] In another aspect, the present application provides an oxime silane or oxime siloxane crosslinker selected from silanes according to formula (I) and hydrolysis or condensation products thereof.

[0027]

[0028] in which:

[0029] a, b, c, R 1 , R 2 , R 3 and R 4 are each defined as described above.

[0030] In another aspect, a cured organosilicon elastomer is provided, which is obtainable by curing an organosilicon formulation as described herein, preferably by curing an organosilicon formulation as described herein by moisture curing.

[0031] In another aspect of the present application, the use of an organosilicon formulation as provided herein or a cured organosilicon elastomer as provided herein as a sealant, grouting compound or adhesive, preferably as a sealant, is provided.

[0032] In another aspect of the application, there is provided a plurality of uses of a first crosslinker as described herein, said first crosslinker being selected from silanes according to formula (I) and hydrolysis or condensation products thereof.

[0033] In another aspect of the application, there is provided a process for preparing a silicone formulation as described herein, comprising the steps of:

[0034] (i) providing at least one hydroxyl-terminated polydiorganosiloxane as described herein;

[0035] (ii) providing:

[0036] (ii.1) a first crosslinker selected from silanes according to formula (I) as defined herein and hydrolysis or condensation products thereof;

[0037] (ii.2) optionally a second silane or siloxane crosslinker selected from silanes according to formula (II) as described herein and hydrolysis or condensation products thereof;

[0038] (iii) optionally, providing further ingredients; and

[0039] (iv) mixing the ingredients provided in step (i), step (ii) and optionally step (iii). DETAILED DESCRIPTION

[0040] Reference to a substance, component or ingredient refers to that substance, component or ingredient as it exists prior to first contact, blending or mixing with one or more other substances, components or ingredients according to the present disclosure. The substance, component or ingredient can acquire a property, performance or characteristic through a chemical reaction or transformation if a chemist of average skill applies common sense and routine skill in the art in contact, blending or mixing according to the present disclosure. Unless otherwise stated herein, the definition of a substance, component or ingredient and their relative amounts relate to the composition prepared at the time of first contact of the ingredients. For example, it is well known to those skilled in the art that contacting a hydroxyl-terminated polydiorganosiloxane as described herein with a silane crosslinker as described herein can result in capping of the polydiorganosiloxane. Capping is typically deliberately carried out by blending the polydiorganosiloxane with the crosslinker and optionally a catalyst prior to addition of the remaining ingredients, as explained elsewhere herein. Any reference to a composition or preparation of a composition comprising a hydroxyl-terminated polydiorganosiloxane, a crosslinker and optionally further ingredients according to the present disclosure, unless otherwise stated, explicitly includes a composition in which the hydroxyl-terminated polydiorganosiloxane has been capped with the crosslinker or the crosslinker mentioned in the composition.

[0041] In a first aspect, the present application provides a silicone formulation comprising a hydroxyl-terminated polydiorganosiloxane and a first crosslinker selected from silanes according to formula (I) and hydrolysis or condensation products thereof:

[0042]

[0043] in which:

[0044] a is 0, 1, 2 or 3;

[0045] b is 0 or 1 ;

[0046] c is 1, 2, 3 or 4;

[0047] a + b + c is 4;

[0048] each occurrence of R 1 and R 2 is individually selected from the group consisting of hydrogen and an optionally substituted monovalent hydrocarbon group having from 1 to 30 carbon atoms; and

[0049] R 3 and R 4 each occurrence of R 3 is methyl and R 4 is hydrogen.

[0050] In one embodiment, the organosilicon formulation as defined herein further comprises a catalyst, preferably an organometallic catalyst, which is present in an amount of 0.01 to 10 wt.-% (relative to the total weight of the organosilicon formulation).

[0051] Crosslinker according to formula (I)

[0052] As shown by the foregoing and the examples, the inventors have found that silicone formulations using a crosslinker selected from silanes according to formula (I) have a number of particular and beneficial properties, such as a reduced or even non-existent early cracking behavior, an increased skinning time, a reduced production of harmful (e.g. carcinogenic) compounds or odors during the curing process.

[0053] As known to the person skilled in the art, silane crosslinkers can be used as such or can be (partially) hydrolyzed and / or condensed to form the corresponding short-chain polysiloxanes. Such hydrolysis and / or condensation usually already occurs to some extent due to the interaction of the silane crosslinker with trace amounts of water before, during or after the preparation of the organosilicon formulation. Thus, the person skilled in the art will understand that the silane crosslinkers described herein can be provided as such or in the form of their hydrolysis or condensation products. In a highly preferred embodiment, the first crosslinker selected from silanes according to formula (I) and their hydrolysis or condensation products is selected from silanes according to formula (I).

[0054] In a preferred embodiment according to the present application, an organosilicon formulation comprising a first crosslinker is provided, the first crosslinker being selected from silanes according to formula (I) and their hydrolysis or condensation products as described herein, wherein:

[0055] R 1Each time it appears, it is selected individually from hydrogen, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 aminoalkyl, C2-C8 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl, C6-C 10 Aryl, -C(O)R 5 -N=CR 6 R 7 and -N=CR 8 ;

[0056] R 5 R 6 and R 7 Selected from C1-C8 alkyl, C2-C8 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl and C6-C 10 Aryl;

[0057] R 8 It is a divalent C2-C8 alkyl group, such that -N = CR 8 It is a cycloalkyl group; and

[0058] R 2 It is selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl and phenyl.

[0059] In a particularly preferred embodiment of the invention, an organosilicon formulation comprising a first crosslinking agent selected from silanes according to formula (I) as described herein and their hydrolysis or condensation products, wherein:

[0060] a is 0;

[0061] b can be 0 or 1, with 1 being preferred;

[0062] c is 3 or 4, with 3 being preferred;

[0063] a+b+c equals 4;

[0064] R 2 Selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl and phenyl, preferably R 2 Selected from hydrogen, methyl, ethyl, vinyl, and phenyl, more preferably R 2 Methyl; and

[0065] R 3 and R 4 R each time it appears 3 It is methyl and R 4 It is hydrogen.

[0066] Based on the present disclosure, the person skilled in the art will understand that this embodiment corresponds to the use of a tri-functional tri(5-methyl-3-heptanone oxime) silane or a tetra-functional tetra(5-methyl-3-heptanone oxime) silane as oxime according to the present application. Furthermore, the present inventors have found that the use of these oximes in their tri-functional methyl silane (i.e. R 2 is methyl) form has the additional advantage that the skin time is increased and the cured silicone is not tacky compared to the corresponding vinyl silane (i.e. R 2 is vinyl). The latter is especially a problem for the corresponding phenyl silane (i.e. R 2 is phenyl) which remains tacky for a long time after curing.

[0067] In a highly preferred embodiment according to the present application, an organosilicon preparation comprising a first crosslinker is provided, the first crosslinker being selected from silanes according to formula (I) as described herein and hydrolysis or condensation products thereof, wherein the first crosslinker selected from silanes according to formula (I) and hydrolysis or condensation products thereof is a tri(5-methyl-3-heptanone oxime) silane, preferably selected from methyl tri(5-methyl-3-heptanone oxime) silane, vinyl tri(5-methyl-3-heptanone oxime) silane and phenyl tri(5-methyl-3-heptanone oxime) silane, most preferably methyl tri(5-methyl-3-heptanone oxime) silane.

[0068] In a highly preferred embodiment according to the present application, an organosilicon preparation comprising a first crosslinker is provided, the first crosslinker being selected from silanes according to formula (I) as described herein and hydrolysis or condensation products thereof, wherein the first crosslinker selected from silanes according to formula (I) and hydrolysis or condensation products thereof is a tetra(5-methyl-3-heptanone oxime) silane.

[0069] In a particularly preferred embodiment according to the present application, an organosilicon preparation is provided comprising a first crosslinker, the first crosslinker being selected from silanes according to formula (I) as described herein and hydrolysis or condensation products thereof, formula (I) wherein:

[0070] a is 2 or 3;

[0071] b is 0 or 1;

[0072] c is 1 or 2;

[0073] a + b + c is 4;

[0074] each occurrence of R 1 is independently selected from C1-C4 alkyl, C2-C4 alkenyl, phenyl, -C(O)R 5 , -N=CR 6 R 7 and -N=CR 8 ;

[0075] R5 R 6 and R 7 is selected from the group consisting of Ci-C8-alkyl, C3-C8-cycloalkyl and phenyl;

[0076] R 8 is a divalent C5-alkyl, such that -N=CR 8 is cyclohexyl; and

[0077] R 2 is selected from the group consisting of hydrogen, Ci-C4-alkyl, C2-C4-alkenyl and phenyl; and

[0078] R 3 and R 4 R 3 is methyl and R 4 is hydrogen.

[0079] Based on the present disclosure, the person skilled in the art will understand that the present embodiment corresponds to the use of 5-methyl-3-heptanone as free oxime in combination with a silane or siloxane crosslinker. Without wishing to be bound by any theory, the inventors believe that the combination of 5-methyl-3-heptanone as free oxime with a silane or siloxane crosslinker leads to the in situ formation of a 5-methyl-3-heptanone oximino silane or siloxane.

[0080] The inventors have found that the combination of 5-methyl-3-heptanone as free oxime with an oximino silane or siloxane crosslinker is particularly beneficial. As shown in the examples, it has been found that the combination with a 2-pentanone oximino silane (also known as methyl propyl-ketoximino silane) is most preferred, such that the silicone formulation has a longer skinning time, an improved early cracking behavior and improved mechanical properties (elastic modulus, elongation at break and / or Shore A hardness). Thus, in a preferred embodiment according to the present application, a silicone formulation is provided comprising a first crosslinker selected from the group consisting of silanes according to formula (I) as described herein and hydrolysis or condensation products thereof, in which formula

[0081] a is 2 or 3;

[0082] b is 0 or 1 ;

[0083] c is 1 or 2;

[0084] a + b + c is 4;

[0085] R 2 is selected from the group consisting of hydrogen, Ci-C4-alkyl, C2-C4-alkenyl and phenyl; and

[0086] R 3 and R 4 R 3 is methyl and R 4 is hydrogen;

[0087] R1 is -N=CR 6 R 7 ; and

[0088] R 6 and R 7 is selected from C1-C8 alkyl, preferably R 6 is methyl and R 7 is propyl.

[0089] In a preferred embodiment according to the present application, there is provided a silicone formulation as described herein, comprising a first crosslinker selected from silanes according to formula (I) and hydrolyzates or condensates thereof, wherein the total amount of silanes according to formula (I) and hydrolyzates or condensates thereof is 0.1 to 15 wt.-% (relative to the total weight of the silicone formulation), preferably 0.5 to 10 wt.-%, more preferably 1-6 wt.-%.

[0090] In a highly preferred embodiment according to the present application, there is provided a silicone formulation as described herein, wherein the hydroxyl-terminated polydiorganosiloxane is at least partially end-capped with the first crosslinker.

[0091] Second crosslinker

[0092] The silicone formulation according to the present application can comprise one or more additional crosslinkers. In some embodiments of the present application, the silicone formulation comprises a first crosslinker selected from silanes according to formula (I) and hydrolyzates or condensates thereof, and further comprises a second silane or siloxane crosslinker.

[0093] In a preferred embodiment of the present application, the silicone formulation comprises a first crosslinker selected from silanes according to formula (I) and hydrolyzates or condensates thereof as described herein, the silicone formulation further comprises a second silane or siloxane crosslinker selected from silanes according to formula (II) and hydrolyzates or condensates thereof:

[0094]

[0095] in which

[0096] d is 3 or 4, preferably 3;

[0097] e is 1 or 0, preferably 1;

[0098] d + e is 4;

[0099] each occurrence of R 9 is individually selected from the group consisting of hydrogen and an optionally substituted monovalent hydrocarbon group having 1 to 30 carbon atoms,

[0100] Preferably, each occurrence of R 9Individually selected from hydrogen, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 aminoalkyl, C2-C8 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl, C6-C 10 Aryl, -C(O)R 11 -N = CR 12 R 13 and -N=CR 14 More preferably, each occurrence of R 9 Individually selected from C1-C4 alkyl, C2-C4 alkenyl, phenyl, -C(O)R 11 -N = CR 12 R 13 and -N=CR 14 Optimal R 9 For N=CR 12 R 13 ,

[0101] R 11 R 12 and R 13 Selected from C1-C8 alkyl, C2-C8 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl and C6-C 10 Aryl; preferably, R 11 R 12 and R 13 Selected from C1-C4 alkyl groups; more preferably, R 11 and R 12 For methyl, R 13 It is propyl;

[0102] R 14 It is a divalent C2-C8 alkyl group, such that -N = CR 14 It is a cycloalkyl group; and

[0103] R 10 Selected from hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms; preferably, R 10 Selected from hydrogen, methyl, ethyl, vinyl, and phenyl; more preferably, R 10 It is a methyl group.

[0104] As will be understood by those skilled in the art, a second silane or siloxane crosslinking agent selected from silanes according to formula (II) and their hydrolysis or condensation products is different from a first crosslinking agent selected from silanes according to formula (I) and their hydrolysis or condensation products.

[0105] As shown in the appended examples, the present inventors have found that the combination of a first crosslinker selected from silanes according to formula (I) and hydrolysis or condensation products thereof as described herein with a second silane or siloxane crosslinker selected from the group consisting of tris-(methylpropyl ketoximato)methylsilane, tris-(methylpropyl ketoximato)vinylsilane and tris-(methylpropyl ketoximato)phenylsilane, in particular tris-(methylpropyl ketoximato)methylsilane, is particularly beneficial and allows to provide formulations with sufficiently long skin times, little or no early cracking and good mechanical properties. Similar formulations using conventional crosslinkers such as methyltris(ketoximato)silane or methyltris(methylethylketoximato)silane as the second silane or siloxane crosslinker were found to have inferior properties, in particular in terms of skin time and / or mechanical properties and / or required higher amounts of the first crosslinker to exhibit satisfactory properties.

[0106] In an embodiment according to the present application, there is provided a silicone formulation as described herein comprising a first crosslinker selected from silanes according to formula (I) and hydrolysis or condensation products thereof and further comprising a second silane or siloxane crosslinker selected from silanes according to formula (II) and hydrolysis or condensation products thereof, wherein the silane according to formula (II) is selected from the group consisting of methyltrimethoxysilane, chloromethyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, methyltripropoxysilane, phenyltripropoxysilane, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, 2-aminoethyl-3- aminopropyltrimethoxysilane, 2-aminoethyl-3-aminopropyltriethoxysilane, N-phenylaminomethyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, bis-(N-methylacetamido)methylethoxysilane, tris-(methyl ethyl ketoximato)methylsilane, tris-(methyl ethyl ketoximato)vinylsilane, tris-(methyl ethyl ketoximato)phenylsilane, tris-(methylpropyl ketoximato)methylsilane, tris-(methylpropyl ketoximato)vinylsilane, tris-(methylpropyl ketoximato)phenylsilane, N,N-bis-(triethoxysilylpropyl)amine, N,N-bis-(trimethoxysilylpropyl)amine, 1,2-bis-(triethoxysilyl)ethane and combinations thereof, preferably selected from tris-(methylpropyl ketoximato)methylsilane, tris-(methylpropyl ketoximato)vinylsilane and tris-(methylpropyl ketoximato)phenylsilane, most preferably from tris-(methylpropyl ketoximato)methylsilane.

[0107] In a highly preferred embodiment according to the present application, there is provided a silicone formulation as described herein, comprising a first crosslinker selected from silanes according to formula (I) as described herein, and hydrolysis or condensation products thereof, and a second silane or siloxane crosslinker selected from formula (II) as described herein, wherein the weight ratio of the second crosslinker to the first crosslinker is in the range of 0.5 to 20, preferably in the range of 2 to 15, more preferably in the range of 6 to 12, most preferably in the range of 8 to 10.

[0108] In a highly preferred embodiment according to the present application, there is provided a silicone formulation as described herein, comprising a first crosslinker selected from silanes according to formula (I) as described herein, and hydrolysis or condensation products thereof, and a second silane or siloxane crosslinker selected from formula (II) as described herein, wherein the weight ratio of the second crosslinker to the first crosslinker is in the range of 0.5 to 20, preferably in the range of 2 to 15, more preferably in the range of 6 to 12, most preferably in the range of 8 to 10; and wherein the total amount of silane or siloxane crosslinker is in the range of 2 to 8 wt.-% (relative to the total weight of the silicone formulation), preferably in the range of 4 to 6 wt.-%, most preferably in the range of 4.5 to 5.5 wt.-%.

[0109] Based on the present disclosure, the skilled person will understand that if the first crosslinker selected from silanes according to formula (I) and hydrolysis or condensation products thereof is prepared in situ by combining 5-methyl-3-heptanone as a free oxime with a silane or siloxane crosslinker, the silicone formulation will inevitably comprise a second silane or siloxane crosslinker (i.e. the unreacted portion of the silane or siloxane crosslinker used to generate the silane according to formula (I)).

[0110] In a highly preferred embodiment according to the present application, there is provided a silicone formulation as described herein, comprising a first crosslinker selected from silanes according to formula (I) as described herein, and hydrolysis or condensation products thereof, and a second silane or siloxane crosslinker selected from formula (II) as described herein, wherein the weight ratio of the second crosslinker to the first crosslinker is in the range of 0.5 to 20, preferably in the range of 2 to 15, more preferably in the range of 6 to 12, most preferably in the range of 8 to 10; and wherein the total amount of silane or siloxane crosslinker is in the range of 2 to 8 wt.-% (relative to the total weight of the silicone formulation), preferably in the range of 4 to 6 wt.-%, most preferably in the range of 4.5 to 5.5 wt.-%.

[0111] Organosilicon formulations obtained from the combination of free oximes and silane crosslinkers

[0112] As described hereinbefore, the present inventors have found that an improved early cracking behavior and / or skinning time can also be obtained by using 5-methyl-3-heptanone as a free oxime and in combination with any silane or siloxane crosslinker. Without wishing to be bound by any theory, the present inventors believe that the combination of 5-methyl-3-heptanone oxime as a free oxime with any silane or siloxane crosslinker can form in situ a silane bearing a 5-methyl-3-heptanone oxime.

[0113] Polydiorganosiloxane (base polymer)

[0114] According to the present application, the hydroxy-terminated polydiorganosiloxane comprised in the silicone formulation as described herein can be any linear or branched polydiorganosiloxane commonly used in silicone formulations and is not particularly limited.

[0115] In an embodiment according to the present application, the hydroxy-terminated polydiorganosiloxane comprises diorganosiloxane repeat units having the structure [-SiR a R b -O-] n wherein n is such that the resulting polymer has a dynamic viscosity of 100 to 500000 mPa-s at 25 °C, wherein R a and R b are independently selected from the group consisting of methyl, ethyl, propyl, butyl, phenyl, methylphenyl, ethylphenyl, vinyl, allyl, cyclohexyl, tolyl, isopropylchloropropyl, 3,3,3-trifluoropropyl, chlorophenyl, beta-(perfluorobutyl)ethyl and chlorocyclohexyl, preferably R a and R b are independently selected from the group consisting of methyl, ethyl, phenyl, vinyl or 3,3,3-trifluoropropyl, most preferably R a and R b are methyl.

[0116] In a preferred embodiment of the present application, the hydroxy-terminated polydiorganosiloxane is a hydroxy-terminated polydialkylsiloxane, preferably a hydroxy-terminated polydimethylsiloxane.

[0117] In a preferred embodiment of the present application, the hydroxy-terminated polydiorganosiloxane has a dynamic viscosity of at least 200 mPa-s, preferably at least 2000 mPa-s, more preferably at least 10000 mPa-s at 25 °C.

[0118] In a preferred embodiment of the present application, the hydroxy-terminated polydiorganosiloxane has a dynamic viscosity of less than 350000 mPa-s, preferably less than 200000 mPa-s, more preferably less than 130000 mPa-s at 25 °C.

[0119] Thus, in a highly preferred embodiment of the present application, the hydroxy-terminated polydiorganosiloxane is a hydroxy-terminated polydialkylsiloxane, preferably a hydroxy-terminated polydimethylsiloxane, having a dynamic viscosity of 200 - 350000 mPa-s, more preferably 2000 - 200000 mPa-s, most preferably 10000 - 130000 mPa-s at 25 °C.

[0120] The determination of the dynamic viscosity of a polysiloxane is known to the person skilled in the art. A preferred method for determining the dynamic viscosity of a hydroxy-terminated polydiorganosiloxane is according to DIN 53019-1 (2008).

[0121] In a preferred embodiment of the present application, the hydroxyl terminated polydiorganosiloxane as described herein is present in an amount of greater than 10 wt.-% (relative to the total weight of the silicone formulation), preferably greater than 20 wt.-%, more preferably greater than 30 wt.-%.

[0122] In an embodiment of the present application, the total amount of any hydroxyl terminated polydiorganosiloxane present in the formulation is 20 to 95 wt.-% (relative to the total weight of the silicone formulation), preferably 25 to 90 wt.-%, more preferably 30 to 80 wt.-%.

[0123] Catalyst

[0124] According to the present application, the silicone formulation as described herein can further comprise a catalyst. In a very preferred embodiment, the catalyst is an organometallic catalyst, which is present in an amount of 0.01 to 10 wt.-% (relative to the total weight of the silicone formulation). The catalyst can be any catalyst conventionally used in silicone formulations, such as organic bases, metal complexes, amines and / or carbenes, and is not particularly limited.

[0125] Examples of suitable organic bases are guanidines or amidines, such as C1-C4 alkyl amidines.

[0126] Examples of suitable metal complexes, preferably organometallic complexes, are metal complexes, wherein the metal is selected from the group consisting of Al, Bi, Co, Fe, Ga, La, Mn, Pb, Pd, Pt, Rh, Sc, Sn, Sr, Ti, Tl, Y, Zn and Zr, more preferably wherein the metal is selected from the group consisting of Ti(IV), Sn(II), Sn(IV), Bi(III), Zn(II) and Zr(IV). Suitable complexing groups include, for example, alkyl groups (e.g. C1-C 20 alkyl) and carboxylates (e.g. C2-C 20 carboxylate).

[0127] Examples of suitable amines include secondary and tertiary amines, such as diazabicyloundecane.

[0128] Suitable catalysts are, for example, catalysts available under the trade name TIB TIBChemicals AG, such as types 216, 217, 218, 219, 221, 223, 226, 229, 232, 233, 248, 318 and 417 from TIBChemicals AG.

[0129] In a preferred embodiment of the present application, there is provided a silicone formulation as described herein, further comprising a catalyst, said catalyst being an organometallic catalyst wherein the metal is selected from the group consisting of Al, Bi, Co, Fe, Ga, La, Mn, Pb, Pd, Pt, Rh, Sc, Sn, Sr, Ti, Tl, Y, Zn and Zr, more preferably comprising a catalyst which is an organotin compound, more preferably the organotin compound is selected from the group consisting of dimethyltin di-2-ethylhexanoate, dimethyltin dilaurate, di-n-butyltin diacetate, di-n-butyltin di-2-ethylhexanoate, di-n-butyltin dioctoate, di-n-butyltin di-2,2-dimethyl octoate, di-n-butyltin dilaurate, di-n-butyltin di-stearate, di-n-butyltin dimaleate, di-n-butyltin dioleate, di-n-octyltin di-2-ethylhexanoate, di-n-octyltin di-2,2-dimethyl octoate, di-n-octyltin dimaleate, di-n-octyltin dilaurate, di-n-butyltin oxide and di-n-octyltin oxide, most preferably di-n-octyltin oxide.

[0130] In a preferred embodiment of the present application, there is provided a silicone formulation as described herein, further comprising a catalyst as described herein, preferably an organometallic catalyst as described herein, wherein the catalyst is present in an amount greater than 0.01 wt% (relative to the total weight of the silicone), preferably greater than 0.05 wt%, more preferably greater than 0.1 wt%.

[0131] In a preferred embodiment of the present application, there is provided a silicone formulation as described herein, further comprising a catalyst as described herein, wherein the catalyst is present in an amount less than 10 wt% (relative to the total weight of the silicone formulation), preferably less than 5 wt%, more preferably less than 1 wt%.

[0132] In a preferred embodiment of the present application, there is provided a silicone formulation as described herein, further comprising a catalyst as described herein, wherein the catalyst is present in an amount of 0.01 to 10 wt% (relative to the total weight of the silicone formulation), preferably 0.05 to 5 wt%, more preferably 0.1 to 1 wt%.

[0133] According to the present application, the total amount of metal catalyst present is less than 10 wt% (relative to the total weight of the silicone formulation), preferably less than 5 wt%.

[0134] Filler

[0135] According to the present application, the silicone formulation as described herein can further comprise a filler. The filler can be any filler conventionally used in silicone formulations and is not particularly limited. As used herein, the term "filler" is intended to include reinforcing fillers (such as fumed silica, precipitated calcium carbonate or carbon black) as well as non-reinforcing fillers (such as heavy calcium carbonate). The filler can also function as a rheology modifier and vice versa (such as fumed silica).

[0136] According to a preferred embodiment of the present application, there is provided the silicone formulation described herein, further comprising a filler, which is also a thickening agent. A preferred filler (which is also a thickening agent) is silica, also known as silicic acid. Silicic acid is a weak acid derived from silicon dioxide, Si02, having the general formula Si02-nH20, where n can vary. Silicic acid is preferred because it binds / interacts with the polymer backbone, significantly improving the physical and mechanical properties of the final product. The inventors have found that various forms of silica can be used as a thickening agent, but fumed silica (also known as "pyrogenic silica") is preferred because of its excellent effect on the mechanical properties (e.g. tear strength) of the final cured product. Suitable fillers for use as a thickening agent are available, for example, from Wacker Company under the trade name Silica® V15, V15A, N20, H13L, H15, H18, from Cabott Company under the trade name Silica® L-90, LM-150, M-5, TS-610, TS-622, from Evonik Company under the trade name Aerosil® 130, 150, 200, R972, R974, from Wacker Company under the trade name Silica®.

[0137] In a preferred embodiment of the present application, there is provided the silicone formulation described herein, further comprising a filler selected from the group consisting of mineral fillers, metal oxide fillers, fly ash, bottom ash, carbon black, and combinations thereof, preferably selected from the group consisting of chalk; calcium hydroxide; natural, ground or precipitated calcium carbonate; dolomite; fumed silica; carbon black; calcined kaolin; boehmite; clay; talc; aluminum silicate; magnesium aluminum silicate; zirconium silicate; finely ground quartz; finely ground cristobalite; diatomaceous earth; mica; iron oxide; titanium oxide; zirconium oxide, and combinations thereof, more preferably selected from the group consisting of chalk, dolomite, fumed silica, and combinations thereof.

[0138] The filler can be surface modified. Surface modification of fillers is known to those skilled in the art. Preferred surface modifications include surface treatment with a fatty acid (e.g. stearic acid) or a silane (e.g. an alkoxysilane). The filler can be a reinforcing filler having a BET surface area of 90 to 300 m 2 / g, preferably 100 to 200 m 2 / g, more preferably 130 to 170 m 2 / g. The filler can be a non-reinforcing filler or a semi-reinforcing filler having a BET surface area of 2 to 90 m 2 / g, preferably 2 to 50 m 2 / g, more preferably 2 to 10 m 2 / g.

[0139] In a preferred embodiment of the present application, there is provided a silicone formulation as described herein further comprising a filler as described herein, wherein the filler is present in an amount greater than 1 wt% (relative to the total weight of the silicone formulation), preferably greater than 3 wt%, more preferably greater than 5 wt%.

[0140] In a preferred embodiment of the present application, there is provided a silicone formulation as described herein further comprising a filler as described herein, wherein the filler is present in an amount less than 60 wt% (relative to the total weight of the silicone formulation), preferably less than 50 wt%, more preferably less than 30 wt%.

[0141] In a preferred embodiment of the present application, there is provided a silicone formulation as described herein further comprising a filler as described herein, wherein the filler is present in an amount of 1-60 wt% (relative to the total weight of the silicone formulation), preferably 3-50 wt%, more preferably 5-30 wt%.

[0142] In other preferred embodiments of the present application, the silicone formulation as described herein further comprises 1-60 wt% (relative to the total weight of the silicone formulation), preferably 3-50 wt%, more preferably 5-30 wt% of a filler selected from the group consisting of mineral fillers, metal oxide fillers, fly ash, bottom ash, carbon black and combinations thereof, preferably selected from the group consisting of calcium hydroxide; natural, ground or precipitated calcium carbonate; dolomite; fumed silica; carbon black; calcined kaolin; boehmite; clay; talc aluminum silicate; magnesium aluminum silicate; zirconium silicate; finely ground quartz; finely ground cristobalite; diatomaceous earth; mica; iron oxide; titanium oxide; zirconium oxide, more preferably selected from the group consisting of dolomite and fumed silica.

[0143] According to the present application, the total amount of filler present is less than 60 wt% (relative to the total weight of the silicone formulation), preferably less than 50 wt%.

[0144] Adhesion promoter

[0145] According to the present application, the silicone formulation as described herein can further comprise an adhesion promoter. The adhesion promoter can be any adhesion promoter conventionally used in silicone formulations and is not particularly limited.

[0146] In a highly preferred embodiment of the present application, there is provided a silicone formulation as described herein further comprising a bonding promoter selected from the group consisting of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3- aminopropyltrimethoxysilane, 3-(2-aminoethylamino)propyltriacetoxysilane, N-(3- trimethoxysilylpropyl)diethylenetriamine, bis-(3-methoxysilylpropyl)-amine, aminoethyl aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyl dimethoxymethylsilane, N-(n-butyl)-3-aminopropyltrimethoxysilane, N-(n-butyl)-3- aminopropyltrimethoxysilane, 3-aminopropylmethyldiethoxysilane, aminoethyl aminotrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3- glycidyloxypropyltriethoxysilane, gamma-ureidopropyltrimethoxysilane, 3- aminopropyl(methyl) silesquioxane, and combinations thereof.

[0147] In a highly preferred embodiment of the present application, there is provided a silicone formulation as described herein further comprising a bonding promoter selected from the group consisting of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3- aminopropyltrimethoxysilane, 3-(2-aminoethylamino)propyltriacetoxysilane, N-(3- trimethoxysilylpropyl)diethylenetriamine, bis-(3-methoxysilylpropyl)-amine, aminoethyl aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyl dimethoxymethylsilane, N-(n-butyl)-3-aminopropyltrimethoxysilane, N-(n-butyl)-3- aminopropyltrimethoxysilane, 3-aminopropylmethyldiethoxysilane, aminoethyl aminotrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3- glycidyloxypropyltriethoxysilane, gamma-ureidopropyltrimethoxysilane, 3- aminopropyl(methyl) silesquioxane, and combinations thereof.

[0148] Suitable bonding promoters can be found, for example, in the product lines of provided by Momentive Performance Materials and Silquest® products line provided by Evonik.

[0149] In a preferred embodiment of the present application, there is provided a silicone formulation as described herein further comprising a bonding promoter as described herein, wherein the bonding promoter is present in an amount greater than 0.01 wt% (relative to the total weight of the silicone formulation), preferably greater than 0.05 wt%, more preferably greater than 0.1 wt%.

[0150] ​In a preferred embodiment of the present application, there is provided a silicone formulation as described herein, further comprising an adhesion promoter as described herein, wherein the adhesion promoter is present in an amount of less than 10 wt.-% (relative to the total weight of the silicone formulation), preferably less than 5 wt.-%, more preferably less than 3 wt.-%.

[0151] In a preferred embodiment of the present application, there is provided a silicone formulation as described herein, further comprising an adhesion promoter as described herein, wherein the adhesion promoter is present in an amount of 0.01 to 10 wt.-% (relative to the total weight of the silicone formulation), preferably 0.05 to 5 wt.-%, more preferably 0.1 to 2 wt.-%.

[0152] According to the present application, the total amount of adhesion promoter present is less than 15 wt.-% (relative to the total weight of the silicone formulation), preferably less than 10 wt.-%.

[0153] Plasticizer

[0154] According to the present application, the silicone formulation as described herein can further comprise a plasticizer. The plasticizer can be any plasticizer conventionally used in silicone formulations and is not particularly limited. A preferred plasticizer is a silicone oil, which can be partially or completely substituted by C 10 -C 30 hydrocarbons.

[0155] Thus, in a preferred embodiment of the present application, there is provided a silicone formulation as described herein, further comprising a plasticizer, which is a linear or branched polydialkylsiloxane containing two or less hydrolysable Si-O bonds, preferably the plasticizer is a trialkylsilyl terminated polydialkylsiloxane, preferably a trimethylsilyl terminated polydimethylsiloxane. The linear or branched polydialkylsiloxane preferably has a dynamic viscosity at 25 °C of 1 to 10 000 mPa-s, preferably a viscosity of 10 to 12 500 mPa-s.

[0156] In a preferred embodiment of the present application, there is provided a silicone formulation as described herein, further comprising a hydrocarbon plasticizer, which hydrocarbon plasticizer consists of one or more C 10 -C 30 hydrocarbons, preferably of one or more C 10 -C 20 hydrocarbons. Preferably, the hydrocarbon plasticizer comprises < 10 wt.-% (relative to the total weight of the hydrocarbon plasticizer) of aromatic compounds, preferably less than 3 wt.-% of aromatic compounds.

[0157] Such products are for example available from ExxonMobil under the trade name D60, D80, D100, D120 or D140, or under the trade name H, J, K, L, M, N or V, or from Total under the trade name D100, G232H, G240H, G3H, G250H, G270H, G400H, G310H, G315H, G340H are provided, or are available from Shell Company under the trade designation D60, D80, D100 are provided, or are available from Petrochem Carless Company under the trade designation 261, 291, 321, 400, 600, 900 are provided, or are available from Nynas Company under the trade designation 8120, 8131, 800 are provided.

[0158] In embodiments of the present application, there is provided a silicone formulation as described herein, further comprising a plasticizer, the plasticizer being an alkyl-terminated poly(alkylene)glycol, preferably a C1-C4-terminated polyethylene glycol or polypropylene glycol.

[0159] In preferred embodiments of the present application, there is provided a silicone formulation as described herein, further comprising a plasticizer as described herein, wherein the plasticizer is present in an amount greater than 1 wt% (relative to the total weight of the silicone formulation), preferably greater than 3 wt%, more preferably greater than 5 wt%.

[0160] In preferred embodiments of the present application, there is provided a silicone formulation as described herein, further comprising a plasticizer as described herein, wherein the plasticizer is present in an amount less than 40 wt% (relative to the total weight of the silicone formulation), preferably less than 35 wt%, more preferably less than 30 wt%.

[0161] In preferred embodiments of the present application, there is provided a silicone formulation as described herein, further comprising a plasticizer as described herein, wherein the plasticizer is present in an amount of 1-60 wt% (relative to the total weight of the silicone formulation), preferably 10-50 wt% relative to the total weight of the silicone formulation, more preferably 20-35 wt%.

[0162] According to the present application, the total amount of plasticizer present is less than 50 wt% (relative to the total weight of the silicone formulation), preferably less than 35 wt%.

[0163] Miscellaneous

[0164] As will be appreciated by those skilled in the art, the silicone formulations described herein can comprise other ingredients (e.g., biocides, pigments, etc.), and the total amount of all ingredients used in the silicone formulation is 100 wt% (relative to the total weight of the silicone formulation).

[0165] In a highly preferred embodiment according to the application, the silicone formulation provided herein is room temperature vulcanizable at room temperature (e.g., 23 °C), preferably under the influence of moisture and thus is moisture curable. In an even more preferred embodiment according to the application, the formulation provided herein is a moisture curable, one-component room temperature vulcanizable (RTVI) silicone sealant formulation.

[0166] In a highly preferred embodiment according to the application, the silicone formulation provided herein is room temperature vulcanizable at room temperature (e.g., 23 °C), preferably under the influence of moisture and thus is moisture curable. In an even more preferred embodiment according to the application, the formulation provided herein is a moisture curable, one-component room temperature vulcanizable (RTVI) silicone sealant formulation.

[0167] As will be appreciated by those skilled in the art, the silicone formulations described herein can be provided as one-component or multi-component (e.g., two-component) systems. The silicone formulations described herein are preferably one-component systems.

[0168] If the silicone formulations described herein are provided as multi-component systems, it will be understood that the relative amounts of the ingredients defined throughout the disclosure are calculated based on the total formulation after the different components have been combined.

[0169] The present inventors have found that while silane or siloxane crosslinkers comprising at least one vinyl group (e.g. tris(alkoxy)vinylsilane or tris(alkoxime)vinylsilane) can be used to improve the early cracking behavior of known oxime silane or siloxane crosslinkers, the silicone formulations of the present invention require less or even none of the silane or siloxane crosslinkers comprising at least one vinyl group in order to avoid early cracking. Thus, as explained elsewhere herein, the compositions of the present invention not only increase skinning time, improve early cracking behavior and improve more than one mechanical property, they also allow for a reduced content of silane or siloxane crosslinkers comprising at least one vinyl group, thereby leading to additional advantages such as reduced costs, and reduced or no gelling during endcapping, which is a typical problem with vinyl silanes. Thus, in a preferred embodiment of the present invention, there is provided a silicone formulation as described herein comprising less than 4 wt.-% of a silane or siloxane crosslinker comprising at least one vinyl group (relative to the total weight of the silicone formulation), preferably less than 1 wt.-%, more preferably less than 0.1 wt.-%. In a highly preferred embodiment, the silicone formulation is essentially free of vinyl-substituted silane or siloxane crosslinkers. Similarly, the use of phenyl silanes can be avoided, such that in a preferred embodiment of the present invention, there is provided a silicone formulation as described herein comprising less than 4 wt.-% of a silane or siloxane crosslinker comprising at least one phenyl group (relative to the total weight of the silicone formulation), preferably less than 1 wt.-%, more preferably less than 0.1 wt.-%. In a highly preferred embodiment, the silicone formulation is essentially free of phenyl-substituted silane or siloxane crosslinkers. Preferably, there is provided a silicone formulation as described herein having a low content of vinyl-substituted silane or siloxane crosslinkers and a low content of phenyl-substituted silane or siloxane crosslinkers.

[0170] Furthermore, according to a preferred embodiment of the present invention, the silicone formulations described herein have one or both of the following properties:

[0171] • a skinning time of more than 10 minutes, preferably more than 15 minutes; and

[0172] • an end of early cracking time of less than 30 minutes, preferably less than 20 minutes, more preferably less than 10 minutes, most preferably no early cracking.

[0173] According to the present invention, the skinning time is determined according to the following method performed at room temperature (about 23 °C) and about 50% relative humidity:

[0174] • applying a 2 mm thick film of the silicone sealant on a 400 pm PE film;

[0175] • every certain time, e.g. every minute, gently touching the top of the film with a finger (or other utensil, like a wooden chopstick), removing the finger or utensil and judging the formation of a skin;

[0176] • the silicone material sticks to the finger (or other implement) and upon removal of the finger or implement, a spike of silicone material protrudes from the surface, indicating no skin formation; and

[0177] • no silicone material sticks to the finger (or other implement) and upon removal of the finger or implement, no spike of silicone material protrudes from the surface, indicating skin formation.

[0178] According to the present application, the early cracking time is determined according to the following method performed at room temperature (about 23 °C) and about 50% relative humidity:

[0179] • a 2 mm thick film of silicone sealant is applied on a 400 pm PE film having a width of 5 cm and a length of 25 cm;

[0180] • every 5 minutes, the film is bent 180° around the horizontal axis (i.e. along a bending path of the longitudinal axis) for 5 seconds with the silicone sealant facing outwards, forming a bend line;

[0181] • the distance between different bend lines is 2 cm, the first bend line being at least 2 cm from the top or bottom edge of the film;

[0182] • the time at which the bend line starts to form a macroscopically visible break or crack is the “early cracking start time” and the time at which no additional cracks or cracks appear is the “early cracking end time”; and

[0183] • the early cracking time is the difference between the “early cracking end time” and the “early cracking start time”.

[0184] If no macroscopically visible break or crack is formed in the bend line after 30 minutes of testing, the system is considered to show no early cracking.

[0185] Compound of formula (I)

[0186] As described throughout the disclosure, the present inventors have found that a particular silane comprising a 5-methyl-3-heptanone oxime can be used as a crosslinker in silicone formulations, in particular silicone sealant formulations. Accordingly, in a further aspect, the present application provides an oxime silane or siloxane crosslinker selected from silanes according to formula (I) and hydrolysis or condensation products thereof:

[0187]

[0188] in which:

[0189] a is 0, 1, 2 or 3;

[0190] b is 0 or 1 ;

[0191] c is 1, 2, 3 or 4;

[0192] a + b + c is 4;

[0193] each occurrence of R 1 and R 2 is individually selected from the group consisting of hydrogen and optionally substituted monovalent hydrocarbon groups having from 1 to 30 carbon atoms; and

[0194] R 3 and R 4 each occurrence of R 3 is methyl and R 4 is hydrogen.

[0195] In a preferred embodiment according to the present application, an oxime silane or siloxane crosslinker is provided, which is selected from silanes according to formula (I) and hydrolysis or condensation products thereof, wherein:

[0196] each occurrence of R 1 is individually selected from the group consisting of hydrogen, Ci-C8alkyl, Ci-C8haloalkyl, Ci-C8aminoalkyl, C2-C8alkenyl, C3-C8cycloalkyl, C4-C8cycloalkenyl, C6-Ci0aryl, -C(O)R 10 , -N=CR 5 , -N=CR 6 R 7 , and -N=CR 8 ;

[0197] R 5 , R 6 , and R 7 are selected from the group consisting of Ci-C8alkyl, C2-C8alkenyl, C3-C8cycloalkyl, C4-C8cycloalkenyl, and C6-Ci0aryl; 10 ;

[0198] R 8 is divalent C2-C8alkyl, such that -N=CR 8 is cycloalkyl; and

[0199] R 2 is selected from the group consisting of hydrogen, Ci-C4alkyl, C2-C4alkenyl, and phenyl.

[0200] In a preferred embodiment according to the present application, an oxime silane or siloxane crosslinker is provided, which is selected from silanes according to formula (I) and hydrolysis or condensation products thereof, wherein:

[0201] a is 0;

[0202] b is 0 or 1, preferably 1;

[0203] c is 3 or 4, preferably 3;

[0204] a + b + c is 4;

[0205] R 2R is selected from the group consisting of hydrogen, C1-C4-alkyl, C2-C4-alkenyl and phenyl, preferably R 2 R is selected from the group consisting of hydrogen, methyl, ethyl, ethenyl and phenyl, more preferably R 2 is methyl; and R

[0206] R 3 and R 4 R is, at each occurrence, independently selected from the group consisting of hydrogen, C1-C4-alkyl, C2-C4-alkenyl and phenyl, preferably R 3 is methyl and R 4 is hydrogen.

[0207] In a highly preferred embodiment according to the present application, an oxime silane or siloxane crosslinker is provided, which is selected from silanes according to formula (I) and hydrolysis or condensation products thereof, wherein:

[0208] a is 0;

[0209] b is 1 ;

[0210] c is 3;

[0211] a + b + c is 4;

[0212] R is selected from the group consisting of hydrogen, C1-C4-alkyl, C2-C4-alkenyl and phenyl, preferably R 2 R is selected from the group consisting of hydrogen, methyl, ethyl, ethenyl and phenyl, more preferably R 2 R is selected from the group consisting of hydrogen, methyl, ethyl, ethenyl and phenyl, more preferably R 2 is methyl; and R

[0213] R 3 and R 4 R is, at each occurrence, independently selected from the group consisting of hydrogen, C1-C4-alkyl, C2-C4-alkenyl and phenyl, preferably R 3 is methyl and R 4 is hydrogen.

[0214] Accordingly, in a highly preferred embodiment according to the present application, the oxime silane or siloxane crosslinker is selected from silanes according to formula (I) and hydrolysis or condensation products thereof, preferably from silanes according to formula (I), wherein the silane according to formula (I) is tris(5-methyl-3-heptanone oximato)silane, preferably methyltris(5-methyl-3-heptanone oximato)silane, vinyltris(5-methyl-3-heptanone oximato)silane or phenyltris(5-methyl-3-heptanone oximato)silane, most preferably methyltris(5-methyl-3-heptanone oximato)silane.

[0215] In a preferred embodiment according to the present application, an oxime silane or siloxane crosslinker is provided, which is selected from silanes according to formula (I) and hydrolysis or condensation products thereof, wherein:

[0216] a is 2 or 3;

[0217] b is 0 or 1 ;

[0218] c is 1 or 2;

[0219] a + b + c is 4;

[0220] each occurrence of R 1 is independently selected from the group consisting of C1-C4 alkyl, C2-C4 alkenyl, phenyl, -C(O)R 5 , -N=CR 6 ; 7 and -N=CR 8 ;

[0221] R 5 , R 6 and R 7 are selected from the group consisting of C1-C8 alkyl, C3-C8 cycloalkyl and phenyl;

[0222] R 8 is a divalent C5 alkyl, such that -N=CR 8 is cyclohexyl; and

[0223] R 2 is selected from the group consisting of hydrogen, C1-C4 alkyl, C2-C4 alkenyl and phenyl; and

[0224] R 3 and R 4 each occurrence of R 3 is methyl and R 4 is hydrogen.

[0225] In a more preferred embodiment according to the application, an oxime silane or siloxane crosslinker is provided, which is selected from silanes according to formula (I) and hydrolysis or condensation products thereof, wherein:

[0226] a is 2 or 3;

[0227] b is 0 or 1;

[0228] c is 1 or 2;

[0229] a + b + c is 4;

[0230] R 2 is selected from the group consisting of hydrogen, C1-C4 alkyl, C2-C4 alkenyl and phenyl; and

[0231] R 3 and R 4 each occurrence of R 3 is methyl and R 4 is hydrogen;

[0232] R 1 is -N=CR 6 R 7 ; and

[0233] R 6 and R 7 are selected from the group consisting of C1-C8 alkyl, preferably R 6R is methyl and R is propyl. 7 R is methyl and R is propyl.

[0234] Cured organosilicon formulation

[0235] In another aspect of the present application, a cured silicone formulation is provided, which is obtainable by curing a silicone formulation as described herein, preferably by moisture curing a silicone formulation as described herein. In a preferred embodiment of the present application, a cured silicone formulation is provided, which is obtainable by curing a silicone formulation as described herein in a temperature range of 5 to 40 °C, preferably by moisture curing a silicone formulation as described herein in a temperature range of 5 to 40 °C.

[0236] In a preferred embodiment according to the present application, a cured silicone formulation as described herein is provided, which has one, two, three or four of the following features:

[0237] • an elastic modulus of 0.15 to 0.5 MPa;

[0238] • a tensile strength of 0.8 to 2 MPa;

[0239] • an elongation at break of 500 to 1500%; and

[0240] • a Shore A hardness of 8 to 20;

[0241] wherein the elastic modulus, the tensile strength and the elongation at break are determined according to DIN 53504 (2017-03) using a 2 mm thick film cured for 1 week at room temperature (23 °C), and the Shore A hardness is determined according to ISO 868 (2003) using a 6 mm thick film.

[0242] Use of organosilicon formulations

[0243] In another aspect of the present application, the use of a silicone formulation as described herein or a cured silicone formulation as described herein as a sealant, grouting compound or adhesive, preferably as a sealant, is provided.

[0244] Use of silanes according to formula (I)

[0245] In another aspect of the present application, the use of a first crosslinker selected from silanes according to formula (I) and hydrolysis or condensation products thereof as described herein for improving the early cracking behavior of a silicone formulation and / or increasing the skinning time of a silicone formulation is provided.

[0246] The present application also provides the use of a crosslinker selected from silanes according to formula (I) and hydrolysis or condensation products thereof as described herein for reducing the amount of vinyl silane in a silicone formulation

[0247] The present application also provides the use of a crosslinker selected from silanes according to formula (I) and hydrolyzates or condensates thereof as described herein for reducing the carcinogenicity of a silicone formulation, preferably while maintaining or improving the early cracking behavior and / or increasing the skinning time.

[0248] The present application also provides the use of a crosslinker selected from silanes according to formula (I) and hydrolyzates or condensates thereof as described herein for reducing malodors caused by the curing of a silicone formulation, preferably while maintaining or improving the early cracking behavior and / or the skinning time.

[0249] According to a preferred embodiment for the use of a crosslinker as described herein, the use described herein preferably involves the use of tris(5-methyl-3-heptanone oximato)silane, preferably selected from methyltris(5-methyl-3-heptanone oximato)silane, vinyltris(5-methyl-3-heptanone oximato)silane and phenyltris(5-methyl-3-heptanone oximato)silane, most preferably methyltris(5-methyl-3-heptanone oximato)silane.

[0250] Process for the preparation of organosilicon formulations

[0251] In another aspect of the present application, a process for the preparation of a silicone formulation as described herein is provided, comprising the following steps:

[0252] (i) providing at least one hydroxyl-terminated polydiorganosiloxane as described herein;

[0253] (ii) providing:

[0254] (ii.1) a crosslinker selected from silanes according to formula (I) and hydrolyzates or condensates thereof as defined herein;

[0255] (ii.2) optionally a silane or siloxane crosslinker selected from silanes according to formula (II) and hydrolyzates or condensates thereof as described herein;

[0256] (iii) optionally, providing further ingredients; and

[0257] (iv) mixing the ingredients provided in step (i), step (ii) and, optionally, step (iii).

[0258] The ingredients provided in steps (i) and (ii) can be mixed by any conventional means, for example by blending, mixing or stirring, preferably under a moisture-free atmosphere. As understood by the skilled person, this process is not to be interpreted as strictly limited to these components. If the silicone formulation comprises additional components, for example catalysts or fillers as discussed herein, step (iii) can comprise mixing any optional further ingredients to obtain a silicone formulation as described herein.

[0259] The order of mixing is not particularly limited. In a preferred embodiment, the compound provided in step (ii.2) is first mixed, thereby forming a crosslinker premix, which is subsequently mixed with the compound provided in step (i) and any other optional further ingredients provided in step (iii).

[0260] As shown in the examples, it is preferred to mix the components provided in steps (i) and (ii) prior to the addition of optional further ingredients such as catalysts, plasticizers, adhesion promoters, etc. This approach leads to a so-called end-capping of the siloxane base polymer with the crosslinker and provides for a more efficient curing of the resulting silicone formulation.

[0261] In a preferred embodiment, the process for preparing a silicone formulation as described herein further comprises the following steps:

[0262] (v) packaging the silicone formulation in a sealed container, such as an aluminum foil or a plastic tube.

[0263] The present application further relates to the following embodiments (A) - (P).

[0264] (A) A silicone formulation comprising a hydroxyl-terminated polydiorganosiloxane, a catalyst, and a first crosslinker selected from the group consisting of silanes according to formula (I) and hydrolysis or condensation products thereof:

[0265]

[0266] wherein:

[0267] a is 0, 1, 2, or 3;

[0268] b is 0 or 1;

[0269] c is 1, 2, 3, or 4;

[0270] a + b + c is 4;

[0271] each occurrence of R 1 and R 2 is individually selected from the group consisting of hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms; R 3 and R 4 each occurrence of R 3 is methyl and R 4 is hydrogen, or each occurrence of R 3 is hydrogen and R 4 is methyl; and wherein the catalyst is an organometallic catalyst present in an amount of 0.01-10 wt. % (relative to the total weight of the silicone formulation).

[0272] (B) The silicone formulation according to embodiment (A), wherein each occurrence of R 1is independently selected from the group consisting of hydrogen, C1-C8alkyl, C1-C8haloalkyl, C1-C8aminoalkyl, C2-C8alkenyl, C3-C8cycloalkyl, C4-C8cycloalkenyl, C6-C10aryl, C7-C15aralkyl, C7-C15alkylaryl, -OR 10 aryl, -C(O)R 5 , -N=CR 6 R 7 and -N=CR 8 ; R 5 , R 6 and R 7 are independently selected from the group consisting of C1-C8alkyl, C2-C8alkenyl, C3-C8cycloalkyl, C4-C8cycloalkenyl and C6-C 10 aryl; R 8 is a bivalent C2-C8alkyl group, such that -N=CR 8 is a cycloalkyl group; R 2 is selected from the group consisting of hydrogen, C1-C4alkyl, C2-C4alkenyl and phenyl.

[0273] (C) The silicone formulation according to embodiment (B), wherein:

[0274] a is 0;

[0275] b is 0 or 1, preferably 1 ;

[0276] c is 3 or 4, preferably 3;

[0277] a + b + c is 4;

[0278] R 2 is selected from the group consisting of hydrogen, C1-C4alkyl, C2-C4alkenyl and phenyl, preferably R 2 is selected from the group consisting of hydrogen, methyl, ethyl, ethenyl and phenyl, more preferably R 2 is methyl; R 3 and R 4 such that each occurrence of R 3 is methyl and R 4 is hydrogen, or each occurrence of R 3 is hydrogen and R 4 is methyl.

[0279] (D) The silicone formulation according to any one of embodiments (A) to (C), preferably according to embodiment (C), comprising a second silane or siloxane crosslinker selected from the group consisting of silanes according to formula (II) and hydrolysis or condensation products thereof:

[0280]

[0281] wherein:

[0282] d is 3 or 4, preferably 3;

[0283] e is 1 or 0, preferably 1 ;

[0284] d + e is 4;

[0285] each occurrence of R 9 is individually selected from the group consisting of hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, preferably each occurrence of R 9 is individually selected from the group consisting of hydrogen, Ci-C8-alkyl, Ci-C8-haloalkyl, Ci-C8-aminoalkyl, C2-C8-alkenyl, C3-C8-cycloalkyl, C4-C8-cycloalkenyl, C6-C 10 aryl, -C(O)R 11 , -N=CR 12 R 13 and -N=CR 14 , more preferably each occurrence of R 9 is individually selected from the group consisting of Ci-C4-alkyl, C2-C4-alkenyl, phenyl, -C(O)R 11 , -N=CR 12 R 13 and -N=CR 14 , most preferably R 9 is N=CR 12 R 13 ; R 11 , R 12 and R 13 are selected from the group consisting of Ci-C8-alkyl, C2-C8-alkenyl, C3-C8-cycloalkyl, C4-C8-cycloalkenyl and C6-C 10 aryl, preferably R 11 , R 12 and R 13 are selected from the group consisting of Ci-C4-alkyl, most preferably R 11 and R 12 are methyl and R 13 is propyl; R 14 is a divalent C2-C8-alkyl group, such that -N=CR 14 is a cycloalkyl group; R 10 is selected from the group consisting of hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, preferably R 10 is selected from the group consisting of hydrogen, methyl, ethyl, ethenyl and phenyl, more preferably R 10 is methyl.

[0286] (E) The silicone formulation according to embodiment (D), wherein the weight ratio of the second crosslinker to the first crosslinker is 0.5 to 20, preferably 2 to 15, more preferably 6 to 12, most preferably 8 to 10; and wherein the total amount of silane or siloxane crosslinker is 2-8 wt.-% (relative to the total weight of the formulation), preferably 4-6 wt.-%, most preferably 4.5-5.5 wt.-%.

[0287] (F) The silicone formulation according to any one of embodiments (A) - (E), wherein the hydroxyl terminated polydiorganosiloxane is at least partially end-capped with the first crosslinker.

[0288] (G) The silicone formulation obtainable by combining a hydroxyl terminated polydiorganosiloxane, a silane or siloxane crosslinker selected from silanes according to formula (II) and hydrolysis or condensation products thereof, and a compound according to formula (III); wherein the compound according to formula (II) is:

[0289]

[0290] wherein d, e, R 9 and R 10 are as defined in embodiment (D); and the compound according to formula (III) is:

[0291]

[0292] wherein R 3 and R 4 are as defined in embodiment (A), R 15 is selected from hydrogen and C1-C4 alkyl, preferably R 15 is hydrogen.

[0293] (H) The silicone formulation according to any one of embodiments (A) - (G), further comprising 1 - 60 wt.-% (relative to the total weight of the silicone formulation), preferably 3 - 50 wt.-%, more preferably 5 - 30 wt.-% of a filler selected from the group consisting of mineral fillers, metal oxide fillers, fly ash, bottom ash, carbon black and combinations thereof, preferably selected from the group consisting of calcium hydroxide; natural, ground or precipitated calcium carbonate; dolomite; fumed silica; carbon black; calcined kaolin; boehmite; clay; talc aluminum silicate; magnesium aluminum silicate; zirconium silicate; finely ground quartz; finely ground cristobalite; diatomaceous earth; mica; iron oxide; titanium oxide; zirconium oxide, more preferably selected from the group consisting of dolomite and fumed silica.

[0294] (I) The silicone formulation according to any one of embodiments (A) - (H), having one or both of the following characteristics:

[0295] • a skin formation time of more than 10 minutes, preferably more than 15 minutes; and

[0296] • an early cracking end time of less than 30 minutes, preferably less than 20 minutes, more preferably less than 10 minutes, most preferably no early cracking.

[0297] (J) A cured silicone elastomer obtainable by curing the silicone formulation according to any one of embodiments (A) - (I), preferably obtainable by moisture curing the silicone formulation according to any one of embodiments (A) - (I).

[0298] (K) Use of the silicone formulation according to any one of embodiments (A) to (J) as a sealant, grouting compound or adhesive, preferably as a sealant.

[0299] (L) Use of a crosslinker selected from silanes according to formula (I) as defined in any one of embodiments (A) to (C) and hydrolysis or condensation products thereof, preferably the crosslinker is selected from silanes according to formula (I) as defined in embodiment (C) and hydrolysis or condensation products thereof:

[0300] • improving the early cracking behavior of the silicone formulation;

[0301] • increasing the skinning time of the silicone formulation;

[0302] • reducing the amount of vinyl silane in the silicone formulation;

[0303] • reducing the carcinogenicity of the silicone formulation, preferably while maintaining or improving the early cracking behavior and / or the skinning time;

[0304] • reducing the malodor caused by curing of the silicone formulation, preferably while maintaining or improving the early cracking behavior and / or the skinning time.

[0305] (M) Use of a compound according to formula (III) as defined in embodiment (G) in:

[0306] • improving the early cracking behavior of a silicone formulation comprising a silane or siloxane crosslinker;

[0307] • increasing the skinning time of a silicone formulation comprising a silane or siloxane crosslinker;

[0308] • reducing the amount of vinyl silane in a silicone formulation comprising a silane or siloxane crosslinker;

[0309] • reducing the carcinogenicity of a silicone formulation comprising a silane or siloxane crosslinker, preferably while maintaining or improving the early cracking behavior and / or increasing the skinning time;

[0310] • reducing the malodor caused by curing of a silicone formulation comprising a silane or siloxane crosslinker, preferably while maintaining or improving the early cracking behavior and / or increasing the skinning time.

[0311] (N) A method of making a silicone formulation according to any one of embodiments (A) to (I) comprising the steps of:

[0312] (i) providing at least one hydroxyl-terminated polydiorganosiloxane;

[0313] (ii) providing at least one of:

[0314] (ii.1) a crosslinker selected from silanes according to formula (I) and hydrolysis or condensation products thereof as defined in any one of embodiments (A) to (C), preferably a crosslinker selected from silanes according to formula (I) and hydrolysis or condensation products thereof as defined in embodiment (C); and

[0315] (ii.2) a silane or siloxane crosslinker selected from silanes according to formula (II) and hydrolysis or condensation products thereof as described in embodiment (G), and a compound according to formula (III) as described in embodiment (G); and

[0316] (iii) mixing the ingredients provided in steps (i) and (ii).

[0317] (O) an oxime silane or siloxane crosslinker selected from silanes according to formula (I) and hydrolysis or condensation products thereof as defined in embodiment (A), with the proviso that the silane according to formula (I) is not methyltris(2-heptanone oxime) silane, vinyltris(2-heptanone oxime) silane or tetrakis(2-heptanone oxime) silane.

[0318] (P) an oxime silane or siloxane crosslinker according to embodiment (O), wherein the silane according to formula (I) is tris(5-methyl-3-heptanone oxime) silane, preferably methyltris(5-methyl-3-heptanone oxime) silane, vinyltris(5-methyl-3-heptanone oxime) silane or phenyltris(5-methyl-3-heptanone oxime) silane, most preferably methyltris(5-methyl-3-heptanone oxime) silane.

[0319] For proper understanding of the present document, including its claims, it should be noted that the verb "to comprise" and its conjugations, used in the present document, are used in their non-limiting sense to mean that items following the word are included, but not to the exclusion of items not specifically recited. Also, the indefinite articles "a" or "an" preceding an element or ingredient of the application are to be understood as referring to one or more than one of the elements / ingredients of the application, unless otherwise indicated. Thus, the indefinite articles "a" or "an" are used in their "at least one" sense unless otherwise indicated.

[0320] The terms first, second, third, etc. that are used in the description and claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. These terms are interchangeable under appropriate circumstances and the embodiments of the present disclosure can operate in other sequences than described or illustrated herein.

[0321] Furthermore, various embodiments, although being referred to as "preferred", should be interpreted as exemplary ways of practicing the present application, but not limiting the scope of the present application.

[0322] The present application will be further illustrated by the following examples, which do not limit the scope of the present application in any way.

[0323] Examples

[0324] A series of one-component RTV1 moisture-curable silicone sealant formulations containing different oxime crosslinkers were prepared. The influence of the oxime crosslinker on the mechanical properties, skinning time and early cracking behavior of the silicone formulations was evaluated.

[0325] Elastic modulus, tensile strength and elongation at break were determined according to DIN 53504 (2017-03) using 2 mm thick films cured for 1 week at room temperature (23 °C), Shore A hardness was determined according to ISO 868 (2003) using 6 mm thick films. Early cracking time and skinning time were determined according to the methods described earlier in this text.

[0326] The system was shown to have no early cracking if no macroscopically visible tears or cracks were formed in the bend line after 30 minutes of testing.

[0327] The sealant formulation contained the following components: hydroxyl terminated polydimethylsiloxane (PDMS) having a dynamic viscosity of 80000 mPa-s at 25 °C, PDMS silicone oil having a dynamic viscosity of 1000 mPa-s at 25 °C, oxime crosslinker as detailed in the table below, hydrophilic fumed silica (filler and thixotropic agent) having a surface area of 150 m 2 / g, aminopropyltrimethoxysilane (AMMO) (adhesion promoter) and dioctyltin oxide (DOTO) (catalyst).

[0328] The following oxime crosslinkers and oximes were used:

[0329] • Me(MEKO)3Si: Methyltris(methyl ethyl ketoximino)silane = Methyltris(2-n- butanoneoximino)silane

[0330] • Me(ACO)3Si: Methyltris(acetoneoximino)silane = Methyltris(2-acetoneoximino)silane

[0331] • Me(2PO)3Si: Methyltris(2-pentanoneoximino)silane

[0332] • Vinyl(2PO)3Si: Vinyltris(2-pentanoneoximino)silane

[0333] • Ph(2PO)3Si: Phenyltris(2-pentanoneoximino)silane

[0334] • Me(MIBKO)3Si: Methyltris(methyl isobutyl ketoximino)silane = Methyltris(4- methyl-2-pentanoneoximino)silane

[0335] • Me(MAKO)3Si: Methyltris(methyl amyl ketoximino)silane = Methyltris(2- heptanoneoximino)silane

[0336] • Me(trem)3Si: Methyltris(methylhexylketoximino)silane = Methyltris(5-methyl-3- heptanoneoximino)silane

[0337] • Me(MiAKO)3Si: Methyltris(methylisopentylketoximino)silane = Methyltris(5- methyl-2-hexanoneoximino)silane

[0338] • MAKO: Methylamylketoxime = 2-heptanone oxime (free oxime)

[0339] • MEKO: Methyl ethyl ketoxime = 2-butanone oxime (free oxime)

[0340] The silicone formulation is prepared using the following mixing procedure using a high speed mixer:

[0341] • The hydroxyl terminated PDMS and silicone oil are mixed and the blend is mixed at 3000 rpm for 30 seconds (mixture 1);

[0342] • The crosslinker (crosslinker 1) is added to mixture 1 and the blend is mixed at 3000 rpm for 30 seconds (mixture 2) and the resulting mixture 2 is stored at 25 °C for 10 minutes;

[0343] • If a second crosslinker is included, this second crosslinker (crosslinker 2) is added to mixture 2 and mixed at 3000 rpm for 30 seconds (mixture 3) and the resulting mixture 3 is stored at 25 °C for 2 minutes;

[0344] • The hydrophilic fumed silica is added to mixture 2 or mixture 3 respectively and the blend is mixed at 3000 rpm for 30 seconds (mixture 4);

[0345] • The adhesion promoter (AMMO) is added to mixture 4 and the blend is mixed at 3000 rpm for 30 seconds (mixture 5);

[0346] • The catalyst (DOTO) is added to mixture 5 and the blend is mixed at 3000 rpm for 30 seconds.

[0347] As shown in the table below, formulations containing Me(MAKO)3Si or Me(trem)3Si have increased skinning times and show little or no cracking behavior. This further demonstrates that the combination of Me(MAKO)3Si and Me(2PO)3Si, whether added separately or as a premixed mixture to the silicone formulation, likewise results in silicone formulations having increased skinning times and / or exhibiting little or no cracking behavior and also having increased Shore A hardness, compared to Me(MAKO)3Si alone. Furthermore, it was surprisingly found that even as a free oxime, the mixture of Me(2PO)3Si and MAKO results in silicone formulations having increased skinning times and / or showing no cracking behavior. The maximum tension mentioned in the table below is also referred to elsewhere herein as tensile strength.

[0348]

[0349]

[0350]

[0351]

[0352]

[0353]

[0354] a The two crosslinkers were first mixed and added as a mixture (crosslinker 1) to the silicone formulation

[0355]

[0356] a The two compounds were first mixed and added as a mixture (crosslinker 1) to the silicone formulation

[0357]

[0358]

[0359] a The two crosslinkers were first mixed and added as a mixture (crosslinker 1) to the silicone formulation

[0360]

[0361] a The silicone formulation was tacky after curing

[0362]

[0363]

[0364] All compounds used are commercially available except Me(trem)3Si and were obtained from various chemical suppliers.

[0365] Me(trem)3Si was synthesized by charging a two liter, three necked, round bottom flask, equipped with a thermometer, an overhead stirrer and an addition funnel, with 436.8 g (3.05 mol) 5-methyl-3-heptanone oxime and 1000 mL hexane. While stirring the contents of the flask, 74.5 g (0.5 mol) methyltrichlorosilane was added dropwise from the addition funnel over 30 minutes. During the addition the reaction temperature was kept between 35-41 °C. After the addition was complete, the reaction mixture was allowed to stand for 10 minutes. The top phase containing hexane and product was separated from the heavy 5-methyl-3-heptanone oxime hydrochloride bottom phase using a separatory funnel. The top phase was neutralized using ammonia gas by bubbling ammonia gas through the liquid for 10 minutes. The solid ammonium chloride was filtered off and the hexane was removed from the filtrate by distillation under reduced pressure to yield 214.9 g (91.5%) of a colorless liquid.

Claims

1. An organosilicon formulation comprising a hydroxyl-terminated polydiorganosiloxane and a first crosslinking agent, wherein the first crosslinking agent is selected from silanes according to formula (I) and their hydrolysis or condensation products: In the formula: a can be 0, 1, 2, or 3; b is 0 or 1; c can be 1, 2, 3, or 4; a+b+c equals 4; Each occurrence of R 1 Individually selected from hydrogen, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 aminoalkyl, C2-C8 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl, C6-C 10 Aryl, -C(O)R 5 -N=CR 6 R 7 and -N=CR 8 ; R 5 R 6 and R 7 Selected from C1-C8 alkyl, C2-C8 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl and C6-C 10 Aryl; R 8 It is a divalent C2-C8 alkyl group, such that -N = CR 8 It is a cycloalkyl group; R 2 Selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, and phenyl; and R 3 and R 4 Make R appear each time 3 It is methyl and R 4 It is hydrogen.

2. The organosilicon formulation according to claim 1, wherein, The organosilicon formulation also contains a catalyst.

3. The organosilicon formulation according to claim 2, wherein, The catalyst is an organometallic catalyst, and the amount of the organometallic catalyst is 0.01-10% by weight relative to the total weight of the organosilicon preparation.

4. The organosilicon formulation according to claim 3, wherein: a is 0; b is 0 or 1; c is 3 or 4; a+b+c equals 4; and R 2 It is selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl and phenyl.

5. The organosilicon formulation according to claim 4, wherein, b is 1.

6. The organosilicon formulation according to claim 4, wherein, c is 3.

7. The organosilicon formulation according to claim 4, wherein, R 2 Selected from hydrogen, methyl, ethyl, vinyl, and phenyl.

8. The organosilicon formulation according to claim 4, wherein, R 2 It is a methyl group.

9. The organosilicon formulation according to claim 1, wherein the organosilicon formulation comprises a second silane or siloxane crosslinking agent, the second silane or siloxane crosslinking agent being selected from silanes according to formula (II) and their hydrolysis or condensation products: In the formula: d is 3 or 4; e is 1 or 0; d+e equals 4; Each occurrence of R 9 Individually selected from hydrogen, C1-C8 alkyl, C1-C8 haloalkyl, C1-C8 aminoalkyl, C2-C8 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl, C6-C 10 Aryl, -C(O)R 11 -N=CR 12 R 13 and -N=CR 14 ; R 11 R 12 and R 13 Selected from C1-C8 alkyl, C2-C8 alkenyl, C3-C8 cycloalkyl, C4-C8 cycloalkenyl and C6-C 10 Aryl; R 14 It is a divalent C2-C8 alkyl group, such that -N = CR 14 It is a cycloalkyl group; R 10 Selected from hydrogen and optionally substituted monovalent hydrocarbon groups having 1 to 30 carbon atoms, and in, The second silane or siloxane crosslinking agent selected from silanes according to formula (II) and their hydrolysis or condensation products is different from the first crosslinking agent selected from silanes according to formula (I) and their hydrolysis or condensation products.

10. The organosilicon formulation according to claim 9, wherein, d is 3.

11. The organosilicon formulation according to claim 9, wherein, e is 1.

12. The organosilicon formulation according to claim 9, wherein, Each occurrence of R 9 Individually selected from C1-C4 alkyl, C2-C4 alkenyl, phenyl, -C(O)R 11 -N=CR 12 R 13 and -N=CR 14 .

13. The organosilicon formulation according to claim 9, wherein, R 9 is N = CR 12 R 13 .

14. The organosilicon formulation according to claim 9, wherein, R 11 R 12 and R 13 Selected from C1-C4 alkyl groups.

15. The organosilicon formulation according to claim 9, wherein, R 11 and R 12 It is methyl and R 13 It is propyl.

16. The organosilicon formulation according to claim 9, wherein, R 10 Selected from hydrogen, methyl, ethyl, vinyl, and phenyl.

17. The organosilicon formulation according to claim 9, wherein, R 10 It is a methyl group.

18. The organosilicon formulation according to claim 9, wherein, The weight ratio of the second crosslinking agent to the first crosslinking agent is 0.5 to 20; the total amount of silane or siloxane crosslinking agent is 2-8% by weight relative to the total weight of the organosilicon formulation.

19. The organosilicon formulation according to claim 18, wherein, The weight ratio of the second crosslinking agent to the first crosslinking agent is 2 to 15.

20. The organosilicon formulation according to claim 18, wherein, The weight ratio of the second crosslinking agent to the first crosslinking agent is 6 to 12.

21. The organosilicon formulation according to claim 18, wherein, The weight ratio of the second crosslinking agent to the first crosslinking agent is 8 to 10.

22. The organosilicon formulation according to claim 18, wherein, The total amount of silane or siloxane crosslinking agent is 4-6% by weight relative to the total weight of the organosilicon formulation.

23. The organosilicon formulation according to claim 18, wherein, The total amount of silane or siloxane crosslinking agent is 4.5-5.5% by weight relative to the total weight of the organosilicon formulation.

24. The organosilicon formulation according to claim 9, wherein, The hydroxyl-terminated polydiorganosiloxane is at least partially capped by a first crosslinking agent.

25. The organosilicon formulation according to claim 9, wherein, The organosilicon formulation further comprises 1-60% by weight of filler relative to the total weight of the formulation, the filler being selected from mineral fillers, metal oxide fillers, fly ash, bottom ash, carbon black, and combinations thereof.

26. The organosilicon formulation according to claim 25, wherein, The silicone preparation also contains 3-50% by weight of filler relative to the total weight of the silicone preparation.

27. The organosilicon formulation according to claim 25, wherein, The silicone preparation also contains 5-30% by weight of filler relative to the total weight of the silicone preparation.

28. The organosilicon formulation according to claim 25, wherein, The filler is selected from calcium hydroxide; natural, ground or precipitated calcium carbonate; dolomite; fumed silica; carbon black; calcined kaolin; boehmite; clay; talc aluminum silicate; magnesium aluminum silicate; zirconium silicate; finely ground quartz; finely ground quartzite; diatomaceous earth; mica; iron oxide; titanium oxide; zirconium oxide.

29. The organosilicon formulation according to claim 25, wherein, The filler is selected from dolomite and fumed silica.

30. The organosilicon formulation according to claim 9, wherein, The organosilicon formulation has one or two of the following characteristics: • The crusting time is more than 10 minutes, and the crusting time is determined using the method described in the instruction manual; and • The early cracking end time is less than 30 minutes, and the early cracking end time is determined using the method described in the instruction manual.

31. The organosilicon formulation according to claim 30, wherein, The skin takes more than 15 minutes to form.

32. The organosilicon formulation according to claim 30, wherein, The early cracking process ended in less than 20 minutes.

33. The organosilicon formulation according to claim 30, wherein, The early cracking process ended in less than 10 minutes.

34. The organosilicon formulation according to claim 30, wherein, The silicone preparation did not crack prematurely.

35. A cured silicone elastomer, wherein the cured silicone elastomer can be obtained by curing the silicone formulation according to any one of claims 1-34.

36. The cured silicone elastomer according to claim 35, wherein, The cured silicone elastomer is obtained by wet curing the silicone formulation according to any one of claims 1-34.

37. Use of the silicone formulation of any one of claims 1-34 or the cured silicone elastomer of claims 35 or 36 as a sealant, grouting compound or adhesive.

38. The use of the organosilicon preparation according to claim 37, wherein, The organosilicon preparation is used as a sealant.

39. A first crosslinking agent selected from the silanes according to formula (I) as defined in any one of claims 1 and 4-8 and their hydrolysis or condensation products is used for the following purposes: • Improves the early cracking behavior of silicone formulations; and / or • Increase the skin formation time of organosilicon formulations; and / or • Reduce the amount of vinylsilane in silicone formulations; and / or • Reduce the carcinogenicity of organosilicon preparations; and / or • Reduces odor caused by the curing of silicone preparations.

40. Use of the first crosslinking agent according to claim 39, wherein the crosslinking agent is selected from silanes according to formula (I) as defined in any one of claims 4-8 and their hydrolysis or condensation products.

41. Use of the first crosslinking agent according to claim 39, wherein the first crosslinking agent is used to reduce the carcinogenicity of the organosilicon preparation while maintaining or improving early cracking behavior and / or skinning time.

42. Use of the first crosslinking agent according to claim 39, wherein the first crosslinking agent is used to reduce odor caused by the curing of the silicone preparation, while maintaining or improving early cracking behavior and / or skinning time.

43. A method for preparing the organosilicon formulation of claim 9, comprising the following steps: (i) A polydiorganosiloxane having at least one hydroxyl-terminated terminal; (ii) Provide: (ii.1) A first crosslinking agent, wherein the first crosslinking agent is selected from silanes of formula (I) as defined in any one of claims 1 and 4-8 and their hydrolysis or condensation products; and (ii.2) Optional second silane or siloxane crosslinking agent, the second silane or siloxane crosslinking agent being selected from the silane according to formula (II) as described in any one of claims 9-17 and 18-23 and its hydrolysis or condensation products; (iii) Optionally, other ingredients may be provided; and (iv) Mix the ingredients provided in steps (i), (ii) and optional (iii).

44. The method for preparing organosilicon formulations according to claim 43, wherein, The first crosslinking agent is selected from silanes according to formula (I) as defined in any one of claims 4-8 and their hydrolysis or condensation products.

45. An oxime silane or siloxane crosslinking agent, wherein the oxime silane or siloxane crosslinking agent is selected from silanes according to formula (I) as defined in claim 1 and their hydrolysis or condensation products.

46. ​​The oxime silane or siloxane crosslinking agent according to claim 45, wherein, The silane according to formula (I) is tris(5-methyl-3-heptanone oxime)silane.

47. The oxime silane or siloxane crosslinking agent according to claim 45, wherein, The silane according to formula (I) is methyltris(5-methyl-3-heptanone oxime)silane, vinyltris(5-methyl-3-heptanone oxime)silane or phenyltris(5-methyl-3-heptanone oxime)silane.

48. The oxime silane or siloxane crosslinking agent according to claim 45, wherein, The silane according to formula (I) is methyltris(5-methyl-3-heptanone oxime)silane.

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