Sealant composition

Abstract

The present invention relates to a single part condensation curable silicone sealant composition suitable for use as a building sealant for silicone structured glazing (SSG) applications, particularly for curtain wall facade systems. The composition optionally contains an alkoxylated MQ silicone resin in the presence of a polysiloxane carrier fluid. The resulting sealant is designed to maintain adhesion integrity and to be stable under extreme climates, in particular at high temperatures, when the composition is cured.

Description

[0001] The present invention relates to a one-part condensation-curable silicone sealant composition, which is suitable for use as a building sealant for silicone structural glazing (SSG) applications, and is particularly suitable for use in curtain wall facade systems.

[0002] The building facade is the main vertical exterior surface of a building. While this can be an exterior wall constructed using traditional materials such as brick, stone and concrete, mid-rise and high-rise buildings are increasingly using curtain wall systems.

[0003] A curtain wall is an exterior surface of a building that carries no loads from the building other than its own weight (often referred to as its dead load), i.e., it is the exterior covering of a building facade that is non-structural and can therefore be made of materials such as glass, which is favored by architects because it allows natural light to enter the building. Such curtain walls are designed to resist air and water penetration and to withstand wind loads (which can be very high depending on the design, height and location of the building) in order to minimize sway by transferring wind loads laterally to the main supporting building structure.

[0004] Curtain walls can be designed as a "system" including a frame (e.g., a steel or aluminum frame), panels (e.g., glass panels), and weather-resistant sealing materials. However, steel frames have largely been replaced by aluminum profiles, which are typically filled with glass panels, including operable windows or vents and shadow boxes if desired. The glass panels or infills (hereinafter referred to as panels) may include single-pane glass panels, laminated glass, double-glazed insulating glass units (IGUs) for windows, or triple-glazed IGUs for windows. The frame / supports may include horizontal aluminum beams and / or vertical aluminum mullions. However, silicone structural glazing (SSG) systems are becoming increasingly preferred, in which frames are kept to a minimum and are often not required.

[0005] SSG is a curtain wall arrangement that utilizes a silicone adhesive / sealant to adhere glass, metal or other panel materials to the building structure, allowing for virtually no damage to the exterior facade while redistributing the loads to the facade structure via the structural adhesive / sealant. This enables the facade to be designed with a frameless appearance without the need to include bulky frames and joints that would detract from the aesthetic appearance of the facade, but may involve the use of a structural sealant support frame if desired or required. Such systems increasingly rely on silicone materials to act as both a weatherproof sealant and an adhesive sealant to adhere the panels, particularly glass panels, to the building structure. For SSG facades, the performance of the silicone adhesive / sealant used to adhere the panels to the building structure is critical.

[0006] Silicone sealants selected for use in SSG systems are chosen due to their physical properties such as

[0007] (i) Excellent resistance to ultraviolet and atmospheric aging;

[0008] (ii) long-term (30 years or more) durability with substantial freedom from cracking, embrittlement and / or degradation in adverse environments such as sunlight, rain, snow and seasonal climate changes;

[0009] (iii) stability and flexibility over a wide temperature range (e.g., -40°C to +150°C);

[0010] (iv) Characteristics such as 50% displacement capacity.

[0011] Because the SSG process is a physical and structural bond between the glass and the carrier, it can be used very effectively to increase the strength of glass or glass and metal assemblies. This can be aided by utilizing glass fins or struts as an additional means of supporting the glass curtain wall as a structural glazing.

[0012] Typically, silicone sealants used as structural sealants are designed to be room temperature vulcanizable (RTV), where room temperature is about 20°C to 25°C. They typically contain -OH-terminated diorganopolysiloxane polymers or alkoxy-terminated polydiorganosiloxanes, which may have an alkylene chain between the terminal and penultimate silicon atoms and one or more suitable crosslinking agents designed to react with -OH and / or alkoxy groups and thereby crosslink the composition to form, for example, an elastomeric sealant product and one or more condensation cure catalysts. Additional ingredients such as reinforcing fillers, non-reinforcing fillers, tackifiers, chain extenders, flame retardants, plasticizers and / or extenders, solvent resistance additives, biocides, etc. are also typically incorporated into these compositions as needed and when desired.

[0013] They can be one-part compositions or multi-part compositions, such as two-part compositions. One-part condensation-curing (RTV) silicone compositions are typically used to produce skin or diffusion-cured silicone elastomers. It is well known to those skilled in the art that alkoxy titanium compounds and / or alkoxy zirconium compounds (i.e., alkyl titanates) are catalysts suitable for curing such one-component moisture-curable silicones. One-part condensation-curing silicone compositions are typically designed to contain no water / moisture in the composition as much as possible, i.e., they are typically stored in a substantially anhydrous form to prevent premature curing during storage prior to use. Skin or diffusion curing (e.g., moisture / condensation) occurs by forming a cured skin at the composition / air interface after the sealant / encapsulant is applied to the surface of the substrate. After the surface skin is produced, the curing rate depends on the diffusion of moisture from the interface of the sealant / encapsulant with air to the inside (or core) of the layer of the applied silicone composition, as well as the diffusion of condensation reaction byproducts / effluents from the inside (or core) of the material to the outside (or surface) and the rate at which the cured skin gradually thickens from the outside / surface to the inside / core over time. Such one-part condensation-curing silicone compositions are applied in layers that are typically thinner than 15 mm. It is known that such compositions, if applied in layers thicker than 15 mm, can result in uncured material in the depth of the material, because moisture diffuses very slowly into very deep parts. The primary source, if not the sole source, of moisture in these compositions is inorganic fillers, such as silica or calcium carbonate when present. The fillers may be rendered anhydrous prior to intermixing with the other ingredients, or water / moisture may be extracted from the mixture during the mixing process to ensure that the resulting sealant composition is substantially anhydrous.

[0014] Silicone sealant compositions having at least one Si-alkoxy bond (e.g., a Si-methoxy bond in a terminal reactive silyl group) and having a polydiorganosiloxane polymeric backbone are widely used as sealants in the construction industry because they have good adhesion and weather resistance, etc. The construction industry also prefers one-component compositions that eliminate the need to mix the components prior to application and compositions with excellent workability.

[0015] As mentioned above, it is very important for structural sealants used in SSG facades to maintain stable adhesion integrity even in extreme climates such as high temperatures (greater than (>) 75°C). Therefore, the structural silicone sealant must have high temperature durability to maintain adhesion integrity when the facade is subjected to combined stresses at said high ambient temperatures or higher, especially to meet the necessary international standards for structural sealants used in SSG systems, such as the European Standard EOTA-ETAG 002 of November 2005, which requires structural sealants to maintain high tensile strength retention and shear strength retention at 80°C, while maintaining a high tear strength retention of more than 75% at room temperature. However, this is difficult to achieve because although both tensile retention and shear strength retention at 80°C can be improved by increasing the crosslink density of the sealant elastomer, an increase in crosslink density generally has the opposite effect on tear strength retention, i.e., tear strength retention tends to decrease with increasing crosslink density.

[0016] A one-part RTV condensation-curable silicone composition is provided, comprising the following components:

[0017] (a) an organopolysiloxane polymer having the formula

[0018] X 3-n R n Si-Z-(R 1 y SiO (4-y) / 2 ) z -SiR 1 2-Z-Si-R n X 3-n (1)

[0019] wherein each X is independently an alkoxy group, each R is an alkyl, alkenyl or aryl group, and each R 1 is an X group, an alkyl group, an alkenyl group or an aryl group and Z is a divalent organic group;

[0020] n is 0 or 1, y is 0, 1 or 2, preferably 2, and z is an integer such that the organopolysiloxane polymer has a viscosity of 10,000 to 150,000 mPa.s at 25°C, in an amount of 30 to 80 wt% of the composition

[0021] (wt.%);

[0022] (b) an alkoxylated MQ silicone resin, optionally in the presence of a polysiloxane carrier fluid, having a molar ratio of M units to Q units of 0.1:1.0 to 1.0:1.0; wherein each Q-type siloxane unit has the structure SiO 4 / 2And the M-type siloxane unit has the structure R 2 2R 8 SiO 1 / 2 - or R 2 2 R 8 SiO 1 / 2 -and The groups exist as mixtures;

[0023] Each R 2 The group is an alkyl group having 1 to 6 carbons; and R 8 is an alkenyl group having 2 to 6 carbon atoms; or R 8 For X 3-n R n Si-Z-group, wherein X, R, Z and n are all as previously defined; wherein at least 50% of R 8 The group is silicon-bonded X 3-

[0024] n R n Si-Z-group;

[0025] Component (b) is present in the composition in an amount of 7.5 wt % to 25 wt %;

[0026] (c) one or more cross-linking agents in the form of a silicon-containing compound having at least two, alternatively at least three, hydrolyzable groups per molecule;

[0027] (d) one or more reinforcing fillers selected from precipitated silica, fumed silica or precipitated calcium carbonate, the reinforcing fillers optionally being hydrophobically treated;

[0028] (e) one or more silicon-containing adhesion promoters;

[0029] (f) one or more condensation cure catalysts selected from catalysts comprising titanate-based compounds, zirconate-based compounds, or mixtures thereof; and optionally

[0030] (g) one or more non-reinforcing fillers, which may be hydrophobically treated.

[0031] It will be appreciated that the total weight percent of the composition is 100 weight percent.

[0032] Also provided herein is an elastomeric sealant material which is the cured product of the composition as described herein.

[0033] Unexpectedly, the elastomeric material resulting from curing the composition herein is able to maintain a high tear strength retention at room temperature (such as above 75%), as well as meet the required high tensile strength retention and shear strength retention (greater than 75%) at 80° C. This is surprisingly achieved upon introduction of component (b) as described herein, resulting in a tear strength retention of above 75% at room temperature, indicating that the composition as defined above will meet the requirements of EOTA-ETAG002, November 2005 after curing.

[0034] Also provided is an elastomeric sealant material obtained or obtainable by the following steps

[0035] (i) mixing together a one-part RTV condensation-curable silicone composition comprising the following components:

[0036] (a) an organopolysiloxane polymer having the formula

[0037] X 3-n R n Si-Z-(R 1 y SiO (4-y) / 2 ) z -SiR 1 2-Z-Si-R n X 3-n (1)

[0038] wherein each X is independently an alkoxy group, each R is an alkyl, alkenyl or aryl group, and each R 1 is an X group, an alkyl group, an alkenyl group or an aryl group and Z is a divalent organic group;

[0039] n is 0 or 1, y is 0, 1 or 2, preferably 2, and z is an integer such that the organopolysiloxane polymer has a relative humidity of 10,000 mPa.s at 25°C.

[0040] to 150,000 mPa.s in an amount of 30 to 80 weight percent (wt.%) of the composition;

[0041] (b) an alkoxylated MQ silicone resin, optionally in the presence of a polysiloxane carrier fluid, wherein the molar ratio of M units to Q units is from 0.1:1.0 to 1.0:1.0; wherein each Q-type siloxane unit has the structure SiO 4 / 2 And the M-type siloxane unit has the structure R 2 2R 8 SiO 1 / 2 - or R 2 2 R8 SiO 1 / 2 -and The groups exist as mixtures;

[0042] Each R 2 The group is an alkyl group having 1 to 6 carbons; and R 8 is an alkenyl group having 2 to 6 carbon atoms; or R 8 For X 3-n R n Si-Z-group, wherein X, R, Z and n are all as previously defined; wherein at least 50% of R 8 The group is silicon-bonded X 3-n R n Si-Z-group;

[0043] Component (b) is present in the composition in an amount of 7.5 wt % to 25 wt %;

[0044] (c) one or more cross-linking agents in the form of a silicon-containing compound having at least two, alternatively at least three, hydrolyzable groups per molecule;

[0045] (d) one or more reinforcing fillers selected from precipitated silica, fumed silica or precipitated calcium carbonate, the reinforcing fillers optionally being hydrophobically treated;

[0046] (e) one or more silicon-containing adhesion promoters;

[0047] (f) one or more condensation cure catalysts selected from catalysts comprising titanate-based compounds, zirconate-based compounds, or mixtures thereof; and optionally

[0048] (g) one or more non-reinforcing fillers, which may be hydrophobically treated;

[0049] as well as

[0050] (ii) curing the composition.

[0051] A method for preparing an elastomeric sealant material is also provided, the method comprising the steps of:

[0052] (i) mixing together components (a) to (g) of the one-part RTV condensation-curable silicone composition as described above and any desired additives; and

[0053] (ii) curing the composition.

[0054] Also provided is the use of a one-part RTV condensation-curable silicone composition in preparing an elastomeric sealant material, the composition comprising the following components:

[0055] (a) an organopolysiloxane polymer having the formula

[0056] X 3-n R n Si-Z-(R 1 y SiO (4-y) / 2 ) z -SiR 1 2-Z-Si-R n X 3-n (1)

[0057] wherein each X is independently an alkoxy group, each R is an alkyl, alkenyl or aryl group, and each R 1 is an X group, an alkyl group, an alkenyl group or an aryl group and Z is a divalent organic group;

[0058] n is 0 or 1, y is 0, 1 or 2, preferably 2, and z is an integer such that the organopolysiloxane polymer has a viscosity of 10,000 to 150,000 mPa.s at 25°C, in an amount of 30 to 80 wt% of the composition

[0059] (wt.%);

[0060] (b) an alkoxylated MQ silicone resin, optionally in the presence of a polysiloxane carrier fluid, wherein the molar ratio of M units to Q units is from 0.1:1.0 to 1.0:1.0; wherein each Q-type siloxane unit has the structure SiO 4 / 2 And the M-type siloxane unit has the structure R 2 2

[0061] R 8 SiO 1 / 2 - or R 2 2 R 8 SiO 1 / 2 - and R 2 □SiO 1 / 2 - groups exist as a mixture;

[0062] Each R 2 The group is an alkyl group having 1 to 6 carbons; and R 8 is an alkenyl group having 2 to 6 carbon atoms; or R 8 For X 3-n R n Si-Z-group, wherein X, R, Z and n are all as previously defined; wherein at least 50% of R 8 The group is silicon-bonded X 3-

[0063] n R n Si-Z-group;

[0064] Component (b) is present in the composition in an amount of 7.5 wt % to 25 wt %;

[0065] (c) one or more cross-linking agents in the form of a silicon-containing compound having at least two, alternatively at least three, hydrolyzable groups per molecule;

[0066] (d) one or more reinforcing fillers selected from precipitated silica, fumed silica or precipitated calcium carbonate, the reinforcing fillers optionally being hydrophobically treated;

[0067] (e) one or more silicon-containing adhesion promoters;

[0068] (f) one or more condensation cure catalysts selected from catalysts comprising titanate-based compounds, zirconate-based compounds, or mixtures thereof; and optionally

[0069] (g) one or more non-reinforcing fillers, which may be hydrophobically treated;

[0070] The elastomeric sealant material provides greater than 75% retention of tensile strength and shear strength at 80°C as measured in accordance with 6.1.4.1.2 of EOTA-ETAG 002, November 2005, while maintaining greater than 75% retention of tear strength at room temperature as measured in accordance with 6.1.4.6.4 of EOTA-ETAG 002, November 2005.

[0071] Such elastomeric sealant materials therefore meet the requirements of EOTA-ETAG 002 of November 2005.

[0072] Also provided is the use of the aforementioned composition as a sealant in the fields of facades, insulating glass, window construction, automotive, solar energy and construction.

[0073] As used herein, the concept “comprising” is used in its broadest sense to mean and encompass the concepts “including” and “consisting of.”

[0074] For the purposes of this application, "substituted" means that one or more hydrogen atoms in a hydrocarbon group are replaced by another substituent. Examples of such substituents include, but are not limited to, halogen atoms such as chlorine, fluorine, bromine, and iodine; groups containing halogen atoms such as chloromethyl, perfluorobutyl, trifluoroethyl, and nonafluorohexyl; oxygen atoms; groups containing oxygen atoms such as (meth)acrylic acid and carboxyl; nitrogen atoms; groups containing nitrogen atoms such as amino functional groups, amido functional groups, and cyano functional groups; sulfur atoms; and groups containing sulfur atoms such as mercapto groups.

[0075] The one-part RTV condensation-curable silicone composition is contacted with the target substrate by any conventional means such as by extrusion, coating, injection, scraping and rolling. The one-part RTV condensation-curable silicone composition is particularly intended to be used as a one-part adhesive sealant for silicone sealant glazing, avoiding the need to mix two or more parts of the composition on site before application to the target substrate. After the one-part RTV condensation-curable silicone composition is applied to the target substrate, it is exposed to atmospheric moisture, thereby causing it to produce a surface layer or diffusion cure by forming a cured surface layer at the composition / air interface after the sealant / encapsulant is applied to the substrate surface. After the surface surface layer is produced, the curing speed depends on the diffusion of moisture from the interface of the sealant / encapsulant with air to the inner side (or core) of the layer of the applied silicone composition, and the diffusion of condensation reaction byproducts / effluents from the inner side (or core) of the material to the outer side (or surface) and the gradual thickening speed of the cured surface layer from the outer side / surface to the inner side / core over time.

[0076] Such an elastomeric sealant material meets the requirements of EOTA-ETAG 002, November 2005, and should therefore assure the user that it can maintain its adhesive integrity under extreme climatic conditions, for example when the facade is subjected to stresses such as wind loads at said high ambient temperatures.

[0077] The components of the composition will now be described in more detail.

[0078] An organopolysiloxane polymer (a) having at least two hydroxyl groups or hydrolyzable groups per molecule

[0079] The organopolysiloxane polymer (a) having at least two hydroxyl groups or hydrolyzable groups per molecule has the following formula:

[0080] X 3-n R n Si-Z-(R 1 y SiO (4-y) / 2 ) z -SiR 1 2-Z-Si-R n X3-n (1)

[0081] In the above formula, each X is independently a hydroxyl group or an alkoxy group, alternatively an alkoxy group. Preferably, the alkoxy group has 1 to 10 carbons. Exemplary alkoxy groups are methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, tert-butoxy, isobutoxy, pentyloxy, hexyloxy and 2-ethylhexyloxy; dialkoxy groups such as methoxymethoxy or ethoxymethoxy, and alkoxyaryloxy such as ethoxyphenoxy groups; alternatively, each X is an alkoxy group having one to six carbons, alternatively one to four carbons, or alternatively a methoxy or ethoxy group. Each R group is an alkyl, alkenyl or aryl group, alternatively each R is an alkyl group with 1 to 6 carbons, an alkenyl group with 2 to 6 carbons (such as vinyl, allyl and hexenyl groups) or an aryl group with 6 to 12 carbons; alternatively each R is an alkyl group with 1 to 6 carbons, or an aryl group with 6 to 12 carbons; alternatively each R is an alkyl group with 1 to 6 carbons, alternatively each R is an ethyl group or a methyl group. In one embodiment, R may include a substituted aliphatic organic group, such as a 3,3,3-trifluoropropyl group, an aminoalkyl group, a polyaminoalkyl group and / or an alkylene oxide group.

[0082] Each R 1 is an X group, or and an R group, provided that cumulatively at least two X groups and / or R groups per molecule 1 The group is a hydroxyl group or a hydrolyzable group. Alternatively, each R 1 is an R group. It is possible that some R 1 The groups may be siloxane branches branching from the polymer backbone and these branches may have terminal groups as described above.

[0083] Each Z is a divalent organic group, typically an alkylene group having 2 to 10 carbons, such as, for example, ethylene, propylene, butylene, pentylene and / or hexylene groups; alternatively an alkylene group having 2 to 6 carbons, alternatively an alkylene group having 2 to 5 carbons. The subscript n is 0 or 1, alternatively 0; each subscript y is 0, 1 or 2, and preferably 2. In one embodiment, each n is 0 and each Z is an alkylene group having 2 to 10 carbons.

[0084] Although y is 0, 1 or 2, substantially y=2, for example at least 90%, alternatively 95% of R 1 y SiO (4-y) / 2The group is characterized in that y = 2. The subscript z is an integer such that the organopolysiloxane polymer has a viscosity of 10,000 mPa.s to 150,000 mPa.s, alternatively 30,000 mPa.s to 140,000 mPa.s at 25°C, so z is an integer from about 300 to 2000. The viscosity of component (a) can be measured at 25°C using a Brookfield DV-III Ultra rheometer according to ASTM D4287 cone and plate method.

[0085] Component (a) is present in the one part RTV condensation-curable silicone composition in an amount of 30 wt % to 90 wt % of the composition, alternatively 35 wt % to 75 wt % of the composition, alternatively 35 wt % to 60 wt %.

[0086] The organopolysiloxane polymer (a) may be a single siloxane represented by formula (1), or it may be a mixture of organopolysiloxane polymers represented by the above formula. Therefore, it may be a "siloxane polymer mixture", so the organopolysiloxane polymer (a) is meant to include any single organopolysiloxane polymer (a) or a mixture of organopolysiloxane polymers (a).

[0087] The degree of polymerization (DP) (i.e., essentially z in the above formula) is generally defined as the number of monomer units in a macromolecule or polymer or oligomer molecule of an organosilicon. Synthetic polymers always consist of a mixture of macromolecular species with different degrees of polymerization and therefore different molecular weights. There are different types of average polymer molecular weights, which can be measured in different experiments. The two most important average polymer molecular weights are the number average molecular weight (Mn) and the weight average molecular weight (Mw). The Mn and Mw of organosilicon polymers can be determined by gel permeation chromatography (GPC) using polystyrene standards with an accuracy of about 10% to 15%.

[0088] The technique is standard and produces Mw, Mn and polydispersity index (PI). Degree of polymerization (DP) = Mn / Mu, where Mn is the number average molecular weight measured from GPC, and Mu is the molecular weight of the monomer unit. PI = Mw / Mn. DP is associated with the viscosity of the polymer via Mw, and the higher the DP, the higher the viscosity. In the present disclosure, the number average molecular weight and weight average molecular weight values ​​of component (a) herein can be measured, for example, using a Waters 2695 separation module (Waters Corporation, MA, USA) equipped with a vacuum degasser and a Waters 2414 refractive index detector. Certified grade toluene flowing at 1.0 mL / min can then be used as an eluent for analysis. Data collection and analysis can be performed using Waters Empower GPC software.

[0089] Alkoxylated MQ resin (b)

[0090] The alkoxylated MQ silicone resin of component (b) is an MQ silicone resin having a molar ratio of M units to Q units of 0.1:1.0 to 1.0:1.0; wherein each Q-type siloxane unit has a structure SiO 4 / 2 And the M-type siloxane unit has the structure R 2 2R 8 SiO 1 / 2 - or R 2 2 R 8 SiO 1 / 2 -and The groups exist as mixtures;

[0091] Each R 2 The group is an alkyl group having 1 to 6 carbons, alternatively 1 to 3 carbons, alternatively a methyl group or an ethyl group; and R 8 is an alkenyl group having 2 to 6 carbons, alternatively 2 to 4 carbons, alternatively a vinyl group or a propenyl group; or R 8 For X 3-n R n Si-Z-group, wherein X, R, Z and n are all as previously defined; wherein at least 50% of R 8 The group is silicon-bonded X 3-n R n Si-Z-groups (wherein Si-H and Si-Vi content is determined by FTIR according to corporate test method CTM1092 of Dow Silicones Corporation, publicly available upon request). In one embodiment, each n is 0 and each Z is an alkylene group having 2 to 10 carbons.

[0092] Therefore, it should be recognized that such X 3-n R n The Si-Z-groups are reactive with both the component (a) organopolysiloxane polymer and the component (c) crosslinking agent and possibly with the component (e) adhesion promoter. It is possible that the resin may also contain a low content of D-type siloxane units = (R 3 R 4 SiO 2 / 2 ) and T-type siloxane units = (R 5 SiO 3 / 2 ), by low content we mean in each case less than 1% by weight of the MQ resin being D groups and T groups. 3 , R 4 and R 5The groups are alkyl or alkenyl groups. "Alkoxylated" means that the M units of the MQ resin must contain an alkoxy group, typically an alkoxy group having 1 to 6 carbons.

[0093] Component (b) The alkoxylated MQ silicone resin, optionally in the presence of a polysiloxane carrier fluid, may be introduced into the composition alone, i.e. in "neat" form, or may be provided in the presence of a polysiloxane carrier fluid, particularly in the presence of X 3-n R n In one embodiment, the polysiloxane carrier fluid is component (a). When provided in a polysiloxane carrier fluid, there is 20 wt % to 75 wt % of the alkoxylated MQ resin, with the remainder being the polysiloxane carrier fluid.

[0094] Component (b) is present in the composition in an amount of 7.5 wt% to 25 wt%, alternatively 7.5 wt% to 22.5 wt%.

[0095] When preparing the examples, it was initially hoped that the use of a branched polymer such as the following would have a similar effect, but as will be seen in the following examples, this was surprisingly not the case, given that the introduction of component (b) into the composition unexpectedly enabled sufficiently high (>75%) tear strength retention at room temperature to be maintained when increasing the tensile strength retention and shear strength retention at 80°C (greater than 75%) by increasing the elastomer crosslink density. The branched polymer in question has the formula:

[0096] [R A d R B 3-d Si-(O-Si R 14 2) x -O]4Si

[0097] It is also possible to provide worked examples where each R A is X as defined above 3-n R n Si-Z-group, each R B is an alkenyl group having 2 to 8 carbon atoms, typically vinyl, allyl and hexenyl, and each R 14 is phenyl or an alkyl group having 1 to 6 carbon atoms, typically methyl and / or ethyl, and the values ​​of the subscripts v, w and x are such that 200 ≥ v ≥ 1, 2 ≥ w ≥ 0 and 200 ≥ x ≥ 1, wherein d is 0 to 3, but R A and R B At least 50% of the total number of groups are R A If desired, such polymers can be used as the polysiloxane carrier liquid for the alkoxylated MQ resin of component (b).

[0098] In the form of a silicon-containing compound having at least two, alternatively at least three hydrolyzable groups per molecule or multiple cross-linking agents (c)

[0099] Component (c) is one or more crosslinking agents in the form of silicon-containing compounds having at least two or at least three hydrolyzable groups per molecule; the crosslinking agent may be, for example, one or more crosslinking agents comprising the formula R 9 4-f SiX' f A crosslinking agent for silicon-containing compounds and their oligomeric reaction products. 9 Selected from the group consisting of hydrocarbon groups having 1 to 6 carbon atoms. X' in the above formula is a hydrolyzable group. The hydrolyzable group X' can be an acyloxy group (e.g., acetoxy, octanoyloxy, and benzoyloxy groups); a ketoxime group (e.g., dimethylketoxime and isobutylketoxime); an alkoxy group (e.g., methoxy, ethoxy, isobutoxy, and propoxy) and an alkenyloxy group (e.g., isopropenyloxy and 1-ethyl-2-methylvinyloxy). Alternatively, each hydrolyzable group X' is an alkoxy group having 1 to 6 carbon atoms.

[0100] Subscript f is 2, 3 or 4, preferably 3 or 4. Typically, when component (a) comprises at least three X' groups per molecule, subscript f is only 2. Thus, the crosslinking agent preferably has at least three or four hydroxyl and / or hydrolyzable groups per molecule that react with the hydroxyl and / or hydrolyzable groups in the organopolysiloxane (a).

[0101] When the silane has a total of three X' silicon-bonded hydroxyl and / or hydrolyzable groups per molecule, the fourth group (R 9 ) are suitably non-hydrolyzable silicon-bonded organic groups. These silicon-bonded organic groups (R 9 ) is suitably a hydrocarbon group optionally substituted by halogen (such as fluorine and chlorine). Such a fourth group (R 9 Examples of the organic group (R) include alkyl groups (e.g., methyl, ethyl, propyl, and butyl); cycloalkyl groups (e.g., cyclopentyl and cyclohexyl); alkenyl groups (e.g., vinyl and allyl); aryl groups (e.g., phenyl and tolyl); aralkyl groups (e.g., 2-phenylethyl) and groups obtained by replacing all or part of the hydrogen in the aforementioned organic groups with halogen. However, preferably, the fourth silicon-bonded organic group (R 9 ) is an alkyl group having 1 to 6 carbons (such as methyl) or an alkenyl group having 2 to 6 carbons (such as vinyl), so that preferred silanes that can be used as crosslinking agents include alkyltrialkoxysilanes, alkenyltrialkoxysilanes and tetraalkoxysilanes.

[0102] However, a wide variety of silane crosslinkers can be used. These include methyltrimethoxysilane (MTM) and methyltriethoxysilane, vinyltrimethoxysilane and vinyltriethoxysilane, isobutyltrimethoxysilane (iBTM), ethyltrimethoxysilane, phenyltrimethoxysilane, alkoxytrioximinosilane, alkenyltrioximinosilane, 3,3,3-trifluoropropyltrimethoxysilane, methyltriacetoxysilane, vinyltriacetoxysilane, ethyltriacetoxysilane, dibutoxydiacetoxysilane, phenyltripropionyloxysilane, methyltri(methylethylketoximino)silane, vinyltri(methylethylketoximino)silane, methyltri(methylethylketoximino)silane, methyltri(isopropenyloxy)silane, vinyltri(isopropenyloxy)silane, polyethyl silicate, n-propyl orthosilicate, ethyl orthosilicate,

[0103] dimethyltetraacetoxydisiloxane, propyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, phenyltrimethoxysilane, methyltriacetoxysilane, ethyltriacetoxysilane, tetra(methylethylketoxime)silane, methyl-tri(methylethylketoxime)silane and vinyl-tri(methylethylketoxime)silane, etc.

[0104] Alternatively, component (c) may be a dipodal molecule having at least two or at least 3 alkoxysilyl terminal groups, for example a compound having the formula

[0105] X 2 3–Si–(CH2) f” –Si–X 2 3.

[0106] Each X 2 is an alkoxy group, an alkenyl group or an alkyl group, and at least two or at least three X 2 The group is an alkoxy group, and the subscript f" is an integer, for example, between 1 and 12. Thus, in the above formula for the bipodal molecule, when each X 2 When it is an alkoxy group, there are six alkoxysilyl terminal groups per molecule. An example is 1,6-bis(trimethoxysilyl)hexane (alternatively known as hexamethoxydisilylhexane), dialkoxy or trialkoxysilyl terminated polypropylene oxide, polyurethane, polyacrylate; polyisobutylene.

[0107] Alternatively, component (c) may be a siloxane having the structure

[0108] R 6 3-Si-O-((R 7 )2SiO) d -Si-R 6 3

[0109] Where R 7 is an alkyl or phenyl group, each R 6 The groups may be the same or different and are selected from R 7 , alkyl, phenyl, alkenyl or alkynyl groups. Such siloxanes may have a viscosity of about 5 mPa.s to about 100,000 mPa.s at 25°C, which may be measured using the same test method as described above. Examples may include trialkoxysilyl-terminated polydialkylsiloxanes, dialkoxy or trialkoxysilyl-terminated polyarylalkylsiloxanes.

[0110] Component (c) is present in a range of 1 wt % to 10 wt % of the one part RTV condensation-curable silicone composition, alternatively 1.25 wt % to 7.5 wt % of the composition, alternatively 1.5 wt % to 5.0 wt % of the composition.

[0111] One or more reinforcing fillers (d)

[0112] The one or more reinforcing fillers identified herein as component (d) are selected from precipitated silica, fumed silica, precipitated calcium carbonate, or a mixture of two or more thereof.

[0113] Preferably the reinforcing inorganic filler may contain one or more finely divided fillers. Typically, the surface area of ​​the reinforcing filler (d) measured according to the BET method (ISO 9277:2010) is at least 15 m 2 / g, alternatively 15m 2 / g to 50m 2 / g, alternatively 15m 2 / g to 25m 2 / g.

[0114] According to the BET method (ISO 9277:2010), the typical surface area of ​​silica reinforcing fillers is at least 50 m 2 In the case of high surface area fumed silica and / or high surface area precipitated silica, the surface area of ​​these high surface area fumed silica and / or high surface area precipitated silica may be 75 m2 / s as measured according to the BET method (ISO 9277:2010). 2 / g to 400m 2 / g, alternatively 100 m / s measured according to the BET method (ISO 9277:2010) 2 / g to 300m 2 / g.

[0115] The reinforcing filler (d) can be treated with hydrophobicity, for example, with one or more aliphatic acids (e.g., fatty acids such as stearic acid, or fatty acid esters such as stearic acid esters), or with organosilanes, organosiloxanes or organosilazane hexaalkyldisilazane or short-chain siloxane diols, so that the filler is hydrophobic and thus easier to handle and obtain a uniform mixture with other adhesive components. Specific examples of organosilanes, organosiloxanes or organosilazanes include, but are not limited to, silanol-terminated trifluoropropylmethylsiloxane, silanol-terminated vinylmethyl (ViMe) siloxane, silanol-terminated methylphenyl (MePh) siloxane, liquid hydroxydimethyl-terminated polydiorganosiloxanes containing an average of 2 to 20 repeating units of diorganosiloxanes per molecule, hydroxydimethyl-terminated phenylmethylsiloxanes, hexaorganodisiloxanes such as hexamethyldisiloxane, divinyltetrasiloxane, dimethyl ... Methyldisiloxanes; hexaorganodisilazanes such as hexamethyldisilazane (HMDZ), divinyltetramethyldisilazane and tetramethylbis(trifluoropropyl)disilazane; hydroxydimethyl terminated polydimethylmethylvinylsiloxane, octamethylcyclotetrasiloxane and silanes including but not limited to methyltrimethoxysilane, dimethyldimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, trimethylchlorosilane, dimethyldichlorosilane, trichloromethylsilane.

[0116] The surface treatment of the filler makes it easy to be wetted by component (a). These surface modified fillers are preferably in a finely divided form and do not clump, and can be uniformly incorporated into the silicone polymer (a). This leads to improved room temperature mechanical properties of the uncured composition. When mixed with component (a), the filler can be pre-treated or can be treated in situ. A small amount of water can be added together with the silica treatment agent as a processing aid.

[0117] Depending on the selected filler, the reinforcing filler (d) may be present in an amount of 2.5% to 60% by weight (wt.%) of the one-part RTV condensation-curable silicone composition. In the case where the selected filler is precipitated silica and / or fumed silica or a combination thereof, the inorganic filler (d) is present in a range of about 5.0% to 35% by weight of the composition, alternatively 5% to 30% by weight of the composition, alternatively 5% to 25% by weight of the composition. However, when the reinforcing filler (d) is precipitated calcium carbonate, the composition will tend to include a larger wt% of the composition, such as 25% to 60% by weight of the composition, alternatively 30% to 60% by weight of the composition, alternatively 35% to 55% by weight of the composition. When component (d) is a mixture of silica and precipitated calcium carbonate, the wt% will generally be between them.

[0118] (e) one or more silicon-containing adhesion promoters

[0119] The one-part RTV condensation-curable silicone composition as described above further comprises one or more silicon-containing tackifiers. The one or more tackifiers (e) are different from the crosslinker (c). For example, the tackifier may be selected from one or more mercaptopropyltrialkoxysilanes, aminopropyltriethoxysilanes, aminopropyltrimethoxysilanes, or amines having the following structure:

[0120] R 10 k (R 11 O) 3-k Si-Z 1 -N(H)-(CH2) m -NH2

[0121] Where R 10 is an alkyl group containing 1 to 10 carbon atoms; each R 11 May be the same or different and be H or R 10 , Z 1 is a straight-chain or branched alkylene group having 2 to 10 carbon atoms, m is 2 to 10, and k is 0 or 1. The adhesion promoter (e) may be one or more mercaptoalkylsilanes and aminosilane adhesion promoters, in each case having two or three hydroxyl or alkoxy groups per molecule. Component (e) may, for example, comprise mercaptopropyltrialkoxysilanes, such as mercaptopropyltrimethoxysilane or mercaptopropyltriethoxysilane; aminopropyltriethoxysilane or aminopropyltrimethoxysilane or may comprise:

[0122] R 10 k (R 11 O) 3-k Si-Z 1 -N(H)-(CH2) m -NH2

[0123] Where R 10 is an alkyl group containing 1 to 10 carbon atoms; each R 11 May be the same or different and be H or R 10 , Z 1 is a linear or branched alkylene group having 2 to 10 carbon atoms, m is 2 to 10, and k is 0 or 1.

[0124] R 10 is an alkyl group containing 1 to 10 carbon atoms, or R 10 is an alkyl group containing 1 to 6 carbon atoms, alternatively R 10 is a methyl group or an ethyl group. 11 May be the same or different and be H or R 10 , alternatively, each R 11For R 10 In an alternative embodiment, all R 11 The groups are the same. 11 When the groups are the same, it is preferred that they are methyl or ethyl groups. 1 is a straight or branched chain alkylene group having 2 to 10 carbon atoms, alternatively 2 to 6 carbon atoms, for example Z 1 It can be a propylene group, a butylene group or an isobutylene group. There can be 2 to 10m groups, in an alternative, m can be 2 to 6, in another alternative, m can be 2 to 5, in yet another alternative, m can be 2 or 3, or m is 2.

[0125] Specific examples include, but are not limited to, aminopropyltriethoxysilane, aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminoisobutylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-2-aminoethylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminoisobutylethyldimethoxysilane, N-(2-aminoethyl)-2-aminoethylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminoisobutylethyldimethoxysilane, N-(2-aminoethyl)-2-aminoethylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, and N-(2-aminoethyl)-2-aminoethylmethyldiethoxysilane. Oxysilane, N-(2-aminoethyl)-3-aminoisobutylethyldiethoxysilane, N-(2-aminoethyl)-2-aminoethylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethylmethoxyethoxysilane, N-(2-aminoethyl)-2-aminoethylmethylmethoxyethoxysilane, N-(2-aminoethyl)-3-aminoisobutylethylmethoxyethoxysilane, N-(2-aminoethyl)-2-aminoethylmethylmethoxyethoxysilane, N-(2-aminopropyl)-3-aminoisobutylmethyldimethoxysilane, N-(2-aminopropyl)-3-aminoisobutylmethyldimethoxysilane Aminopropylmethyldimethoxysilane, N-(2-aminopropyl)-2-aminoethylmethyldimethoxysilane, N-(2-aminopropyl)-3-aminoisobutylethyldimethoxysilane, N-(2-aminopropyl)-2-aminoethylmethyldimethoxysilane, N-(2-aminopropyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminopropyl)-2-aminoethylmethyldiethoxysilane, N-(2-aminopropyl)-3-aminoisobutylethyldiethoxysilane, N-(2-aminopropyl)-2-aminoethylmethyldiethoxysilane, N-(2-aminopropyl)-3-aminoisobutylethyldiethoxysilane The invention also includes 3-(2-aminoethyl)-aminopropyltriethoxysilane, 3-(2-aminoethyl)-aminopropyltrimethoxysilane, N-(3-(trimethoxysilyl)propyl)butylamine and bis(trimethoxysilylpropyl)amine.

[0126] When present, the tackifier is present in an amount from 0.1% to 3.75% by weight of the composition, alternatively from 0.1% to 2.5% by weight of the composition, alternatively from 0.1% to 2.0% by weight of the composition, alternatively from 0.2% to 1.0% by weight of the composition.

[0127] (f) a catalyst selected from a group consisting of a titanate-based compound, a zirconate-based compound or a mixture thereof One or more condensation curing catalysts

[0128] Component (f) comprises a condensation catalyst that increases the rate at which the composition cures. The titanate-based and / or zirconate-based catalyst may comprise a catalyst according to the general formula Ti[OR 22 ]4 or Zr[OR 22 ]4, wherein each R 22 may be identical or different and represent a monovalent primary, secondary or tertiary aliphatic hydrocarbon group, which may be linear or branched and contain 1 to 10 carbon atoms. Optionally, the titanate may contain partially unsaturated groups. However, R 22 Preferred examples include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, and branched secondary alkyl groups such as 2,4-dimethyl-3-pentyl. 22 The same, and R 22 is isopropyl, a branched secondary alkyl group or a tertiary alkyl group, in particular tert-butyl.

[0129] For purposes of illustration, suitable examples include tetra-n-butyl titanate, tetra-tert-butyl titanate, tetra-tert-butoxy titanate, tetra-isopropoxy titanate, and zirconate equivalents.

[0130] Alternatively, the titanate may be chelated. Chelation may employ any suitable chelating agent, such as alkyl acetylacetonates, such as methyl acetylacetonate or ethyl acetylacetonate. Alternatively, the titanate may be a monoalkoxy titanate with three chelating agents, such as 2-propanol, triisooctadecanoic acid titanate and diisopropoxy diethyl acetoacetic acid titanate or ethyl acetoacetic acid titanium complex mixed with methyl-trimethoxysilane. Component (f) may be present in any suitable amount, such as 0.05 wt % to 1.5 wt % of a single-part RTV condensation-curable silicone composition, alternatively 0.05 wt % to 1.25 wt % of the composition, alternatively 0.1 wt % to 1.0 wt % of the composition, alternatively 0.1 wt % to 0.75 wt % of the composition.

[0131] (g) one or more non-reinforcing fillers, which may be hydrophobically treated.

[0132] Non-reinforcing fillers that may be used in addition to component (d) herein include bauxite, calcium sulfate (anhydrite), gypsum, nepheline, syenite, quartz, calcium sulfate, magnesium carbonate, ground calcium carbonate, clays such as kaolin, alumina trihydrate, magnesium hydroxide (brucite), graphite, copper carbonates such as malachite, nickel carbonates such as trevally, barium carbonates such as witherite, and / or strontium carbonates such as strontianite.

[0133] Alumina, silicates selected from the group consisting of: olivines; garnets; aluminosilicates; cyclosilicates; inosilicates; and sheet silicates. Olivines include silicate minerals such as, but not limited to, forsterite and Mg2SiO4. Garnets include ground silicate minerals such as, but not limited to, pyrope; Mg3Al2Si3O 12 ; grossular garnet; and Ca2Al2Si3O 12 Aluminosilicates include ground silicate minerals such as, but not limited to, sillimanite; Al2SiO5; mullite; 3Al2O3.2SiO2; kyanite; and Al2SiO5.

[0134] Cyclosilicates include silicate minerals such as, but not limited to, cordierite and Al3(Mg,Fe)2[Si4AlO 18 ]. Inosilicates include ground silicate minerals such as, but not limited to, wollastonite and Ca[SiO3].

[0135] Sheet silicates include silicate minerals such as, but not limited to, mica; K2AI 14 [Si6Al2O 20 ](OH)4; pyrophyllite; Al4[Si8O 20 ](OH)4; Talc; Mg6[Si8O 20 ](OH)4; serpentine, such as asbestos; kaolinite; Al4[Si4O 10 ](OH)8; and vermiculite.

[0136] Such additional fillers can also be hydrophobically treated in the same manner as above-mentioned component (d). When present, non-reinforcing fillers tend to be used to replace some components (d), so when component (d) reinforcing filler is precipitated calcium carbonate and non-reinforcing filler is also present in the composition, the total amount of precipitated calcium carbonate and non-reinforcing filler will still not exceed the upper limit 60 wt % of the composition. In one embodiment of the composition, when component (d) is precipitated calcium carbonate, the composition also includes heavy calcium carbonate. When present, non-reinforcing fillers can exist in an amount greater than 0 wt % to 20 wt % of the composition.

[0137] Optional additives

[0138] Optional additives may be used if desired. These may include pigments, rheology modifiers, cure modifiers, and fungicides and / or biocides, among others; it should be understood that some of these additives may be included in more than one additive list. Such additives will then have the ability to function in the different ways involved.

[0139] pigment

[0140] The one-part RTV condensation-curable silicone composition as described herein may also include one or more pigments and / or colorants. The pigments and / or colorants may be colored, white, black, metallic, and luminescent, such as fluorescent and phosphorescent. The composition may be colored using pigments as desired. Any suitable pigment may be used that provides compatibility with the composition herein. In the one-part RTV condensation-curable silicone composition, pigments and / or colored (non-white) fillers such as carbon black may be used in the catalyst package to color the final sealant product.

[0141] Suitable white pigments and / or colorants include titanium dioxide, zinc oxide, lead oxide, zinc sulfide, lithopone, zirconium oxide, and antimony oxide.

[0142] Suitable non-white inorganic pigments and / or colorants include, but are not limited to, iron oxide pigments such as goethite, lepidocrocite, hematite, maghemite and maghemite black, yellow, brown and red iron oxides; blue iron pigments; chromium oxide pigments; cadmium pigments such as cadmium yellow, cadmium red and cadmium cinnabar; bismuth pigments such as bismuth vanadate and bismuth vanadate molybdate; mixed metal oxide pigments such as cobalt titanate green; chromate and molybdate pigments such as chrome yellow, molybdenum red and molybdenum orange; ultramarine pigments; cobalt oxide pigments; nickel antimony titanate; lead chromium; carbon black (when present, carbon black will act as both a non-reinforcing filler and a colorant); lamp black and metallic effect pigments such as aluminum, copper, copper oxide, bronze, stainless steel, nickel, zinc and brass.

[0143] Suitable organic non-white pigments and / or colorants include phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green; monoarylate yellows, diarylate yellows, benzimidazolone yellows, heterocyclic yellows, DAN oranges, quinacridone pigments such as quinacridone magenta and quinacridone violet; organic reds including metallized azo reds and non-metallized azo reds as well as other azo pigments, monoazo pigments, diazo pigments, azo pigment lakes, β-naphthol pigments, naphthol AS pigments, benzimidazolone pigments, diazo condensation pigments, isoindolinone and isoindolinone pigments, polycyclic pigments, perylene and perindole pigments, thioindigo pigments, anthrapyrimidone pigments, flavonoid pigments, anthraquinone pigments, dioxazine pigments, triarylcarbonium pigments, quinophthalone pigments, and diketopyrrolopyrrole pigments.

[0144] Typically, the pigment and / or colorant, when particulate, has an average particle size in the range of 10 nm to 50 μm, preferably in the range of 40 nm to 2 μm. When present, the pigment and / or colorant is present in the range of 2 wt%, alternatively 3 wt%, alternatively 5 wt% to 20 wt% of the composition.

[0145] Rheology Modifiers

[0146] Rheology modifiers that can be incorporated into the one-part RTV condensation-curable silicone composition include silicone organic copolymers, such as those described in EP0802233 based on polyether or polyester polyols; nonionic surfactants selected from the group consisting of polyethylene glycols, polypropylene glycols, ethoxylated castor oils, oleic acid ethoxylates, alkylphenol ethoxylates, copolymers of ethylene oxide and propylene oxide, and silicone polyether copolymers; and silicone diols. For some systems, these rheology modifiers, especially copolymers of ethylene oxide and propylene oxide and silicone polyether copolymers, can enhance adhesion to substrates, especially plastic substrates.

[0147] UV and / or light stabilizers

[0148] For purposes of example, the UV and / or light stabilizer may include benzotriazole, ultraviolet light absorber and / or hindered amine light stabilizer (HALS), such as HALS from Ciba Specialty Chemicals Inc. Product series.

[0149] Biocides

[0150] If desired, a biocide may be additionally utilized in the composition. The term "biocide" is intended to include bactericides, fungicides, algaecides, and the like. For purposes of illustration, suitable examples of useful biocides that may be utilized in the compositions described herein include:

[0151] Carbamates, such as methyl-N-benzimidazol-2-ylcarbamate (carbendazim) and other suitable carbamates; 10,10'-oxybisphenoxadiazole; 2-(4-thiazolyl)-benzimidazole;

[0152] N-(Fluorodichloromethylthio)phthalimide, diiodomethyl-p-tolylsulfone, if appropriate in combination with UV stabilizers such as 2,6-di(tert-butyl)-p-cresol, 3-iodo-2-propynylbutylcarbamate (IPBC), zinc 2-pyridinethiol 1-oxide, triazole compounds and isothiazolinones such as 4,5-dichloro-2-(n-octyl)-4-isothiazolin-3-one (DCOIT), 2-(n-octyl)-4-isothiazolin-3-one (OIT) and n-butyl-1,2-benzisothiazolin-3-one (BBIT). Other biocides may include, for example, zinc pyrithione, 1-(4-chlorophenyl)-4,4-dimethyl-3-(1,2,4-triazol-1-ylmethyl)pentan-3-ol, and / or 1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-1H-1,2,4-triazole.

[0153] The fungicide and / or biocide may suitably be present in an amount of from 0% to 0.3% by weight of the composition and may if desired be present in encapsulated form such as described in EP2106418.

[0154] Thus, the one-part RTV condensation-curable silicone composition described herein suitable for application to a porous substrate at a temperature of at least 40° C. may comprise

[0155] An organopolysiloxane polymer (a) having at least two hydroxyl groups or hydrolyzable groups per molecule of the following formula:

[0156] X 3-n R n Si-Z-(R 1 y SiO (4-y) / 2 ) z -SiR 1 2-Z-Si-R n X 3-n (1)

[0157] wherein each X is independently a hydroxyl group or an alkoxy group, each R is an alkyl, alkenyl or aryl group, and each R 1 is an X group, an alkyl group, an alkenyl group or an aryl group and Z is a divalent organic group;

[0158] n is 0 or 1, y is 0, 1 or 2, and preferably 2, and z is an integer such that the organopolysiloxane polymer has a viscosity of 10,000 to 150,000 mPa.s at 25°C, alternatively 30,000 to 140,000 mPa.s at 25°C according to Corporate Test Method CTM0050, which is publicly available and based on ASTM D1084-16 Method B, using a Brkfield HBDV-III Ultra Rheometer equipped with cone-plate geometry, using spindle 52, the organopolysiloxane polymer being in an amount of 30 to 90 wt % of the composition, alternatively 35 to 75 wt %, alternatively 35 to 60 wt % of the composition;

[0159] (b) an alkoxylated MQ silicone resin, optionally in the presence of a polysiloxane carrier fluid, having a molar ratio of M units to Q units of 0.1:1.0 to 1.0:1.0; wherein each Q-type siloxane unit has the structure SiO 4 / 2 And the M-type siloxane unit has the structure R 2 2R 8 SiO 1 / 2 - or R 2 2 R 8 SiO 1 / 2 -and The groups exist as mixtures;

[0160] Each R 2 The group is an alkyl group having 1 to 6 carbons; and R 8 is an alkenyl group having 2 to 6 carbon atoms; or R 8 For X 3-n R n Si-Z-group, wherein X, R, Z and n are all as previously defined; wherein at least 50% of R 8 The group is silicon-bonded X 3-n R n Si-Z-group;

[0161] Component (b) is present in the composition in an amount of 7.5 wt % to 25 wt %; alternatively, in an amount of 7.5 wt % to 22.5 wt %;

[0162] (c) one or more crosslinking agents in the form of silicon-containing compounds having at least two, alternatively at least three hydrolyzable groups per molecule, present in a range of 1% to 10% by weight of the composition, alternatively 1.25% to 7.5% by weight of the composition, alternatively 1.5% to 5.0% by weight of the composition;

[0163] (d) one or more reinforcing fillers selected from the group consisting of: 2 / g of precipitated silica or fumed silica or silica having a surface area of ​​at least 15 m / s measured according to the BET method (ISO 9277:2010) 2 / g of surface area of ​​precipitated calcium carbonate; the amount of reinforcing filler is 2.5 weight percent to 60 weight percent (wt.%) of the composition, wherein when the selected filler is precipitated silica and / or fumed silica or a combination thereof, the inorganic filler (d) is present in a range of about 5.0 wt.% to 35 wt.% of the composition, alternatively 5 wt.% to 30 wt.% of the composition, alternatively 5 wt.% to 25 wt.% of the composition, and wherein when the selected filler is precipitated calcium carbonate, the composition will tend to include a greater wt.% of the composition, such as 25 wt.% to 60 wt.% of the composition, alternatively 30 wt.% to 60 wt.% of the composition, alternatively 35 wt.% to 55 wt.% of the composition;

[0164] (e) one or more silicon-containing adhesion promoters, such as mercaptopropyltrialkoxysilane; aminopropyltriethoxysilane or aminopropyltrimethoxysilane or may include:

[0165] R 10 k (R 11 O) 3-k Si-Z 1 -N(H)-(CH2) m -NH2

[0166] Where R 10 is an alkyl group containing 1 to 10 carbon atoms; each R 11 May be the same or different and be H or R 10 , Z 1 is a straight or branched alkylene group having 2 to 10 carbon atoms, m is 2 to 10, and k is 0 or 1. The tackifier is present in an amount of 0.1% to 3.75% by weight of the composition, or in an amount of 0.1% to 2.5% by weight of the composition, or in an amount of 0.1% to 2.0% by weight of the composition, or in an amount of 0.2% to 1.0% by weight of the composition.

[0167] Component (f) comprises a condensation catalyst that increases the rate at which the composition cures. The titanate-based and / or zirconate-based catalyst may comprise a catalyst according to the general formula Ti[OR 22 ]4 or Zr[OR 22 ]4, wherein each R 22may be identical or different and represent a monovalent primary, secondary or tertiary aliphatic hydrocarbon group, which may be linear or branched and contain 1 to 10 carbon atoms. Optionally, the titanate may contain partially unsaturated groups. However, R 22 Preferred examples include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, and branched secondary alkyl groups such as 2,4-dimethyl-3-pentyl. 22 The same, and R 22 is isopropyl, a branched secondary alkyl group or a tertiary alkyl group, in particular tert-butyl.

[0168] For purposes of illustration, suitable examples include tetra-n-butyl titanate, tetra-t-butyl titanate, tetra-t-butoxy titanate, tetra-isopropoxy titanate, and zirconate equivalents. Alternatively, the titanate may be chelated. Component (f) may be present in any suitable amount, such as 0.05 wt % to 1.5 wt % of the one-part RTV condensation-curable silicone composition, alternatively 0.05 wt % to 1.25 wt % of the composition, alternatively 0.1 wt % to 1.0 wt % of the composition,

[0169] Component (g) is one or more non-reinforcing fillers which may be hydrophobically treated.

[0170] In addition to component (d) herein, non-reinforcing fillers that can be used include bauxite, calcium sulfate (anhydrite), gypsum, nepheline, syenite, quartz, calcium sulfate, magnesium carbonate, heavy calcium carbonate, clays such as kaolin, trihydrated aluminum oxide, magnesium hydroxide (brucite), graphite, copper carbonate such as malachite, nickel carbonate such as truncatite, barium carbonate such as witherite and / or strontium carbonate such as strontianite. When present, non-reinforcing fillers tend to be used to replace some components (d). Therefore, when component (d) reinforcing filler is precipitated calcium carbonate and non-reinforcing filler is also present in the composition, the total amount of precipitated calcium carbonate and non-reinforcing filler will still not exceed the upper limit of 60% by weight of the composition. In one embodiment of the composition, when component (d) is precipitated calcium carbonate, the composition also includes heavy calcium carbonate. In one embodiment, component (d) reinforcing filler is precipitated calcium carbonate and component (g) is heavy calcium carbonate, and the total amount of precipitated calcium carbonate+heavy calcium carbonate is 30% to 60% by weight of the composition. When present, non-reinforcing fillers may be present in amounts from greater than 0% to 20% by weight of the composition.

[0171] The one-part RTV condensation-curable silicone composition may include any combination of the above-described materials, provided that the total composition of ingredients (a) to (g) and any other optional ingredients included in the composition has a value of 100% by weight of the composition.

[0172] A method for preparing an elastomeric sealant material is also provided, the method comprising the steps of:

[0173] (i) mixing together components (a) to (g) of the one-part RTV condensation-curable silicone composition as described above and any desired additives; and

[0174] (ii) curing the composition.

[0175] The one-part RTV condensation-curable silicone composition described above can, for example, be initially prepared by mixing all of the ingredients together in any suitable order.

[0176] For example, components (a) the organosilicone polymer, (c) the crosslinking agent, (e) the tackifier and (f) the catalyst may be initially mixed together, then components (d) the reinforcing filler and (g) the non-reinforcing filler may be added and mixed for at least 10 minutes, alternatively at least 15 minutes, alternatively 20 minutes or more, after which component (b) and optionally one or more optional additives may be added as desired, and the composition may then be used as a sealant composition or packaged into a suitable sealant box, etc. prior to use. The filler is anhydrous if possible.

[0177] In an alternative method, a one-part RTV condensation-curable silicone composition as described above may be prepared by first mixing reinforcing fillers (d), non-reinforcing fillers (g) and / or pigments, where present, into an organopolysiloxane polymer (a), optionally, if desired, in combination with a hydrophobic treatment agent, such that the fillers and optional pigments may be hydrophobically treated in situ during mixing into the polymer. Once the fillers are thoroughly mixed into the polymer (and, if desired, have been hydrophobically treated), the remaining components are added in any suitable order to prepare the complete composition. In the latter case, the method for preparing a one-part RTV condensation-curable silicone composition may include the following steps:

[0178] 1) if deemed necessary, gradually adding the or each reinforcing filler (d) and any non-reinforcing filler (g) (when present) and, if desired, a hydrophobic filler treating agent to the organopolysiloxane polymer (a) under vacuum for a predetermined period of time; to form a polymer matrix;

[0179] 2) if deemed necessary, adding the remaining ingredients to the mixture obtained from step (1) in each case under vacuum, or preparing a premix of the remaining ingredients which is then introduced individually into the mixture in any suitable order of step (1);

[0180] Finally the vacuum is released and the final composition is packaged if it is to be stored.

[0181] As indicated previously, preferably once mixed, the composition is sealed in one or more moisture proof containers and stored unless used immediately.

[0182] The one-part RTV condensation-curable silicone composition is applied to one or more substrates selected from glass, metal, stone, marble, brick, concrete, cement and other cementitious substrates and / or combinations thereof prior to curing.

[0183] Also provided herein is an elastomeric sealant material which is a cured product of the one-part RTV condensation-curable silicone composition as described above.

[0184] We have found that surprisingly by incorporating the alkoxylated MQ resin of component (b) into the compositions herein, we are able to provide improved high temperature durability, even at temperatures greater than (>) 75°C, and even greater than (>) 80°C. This provides the ability to maintain the adhesion integrity of the facade joint when subjected to combined stresses at said high ambient temperatures or higher. After curing as previously shown, the elastomeric materials described herein are able to maintain high tensile strength retention and shear strength retention (greater than 75%) at 80°C in each case, while maintaining a high tear strength retention of greater than 75% at room temperature to meet the International Standard EOTA-ETAG 002 of November 2005. It has previously been found that this is exceptionally difficult to achieve in the case of elastomeric materials cured from one-part sealant compositions designed to undergo skin or diffusion cure, because unlike previous compositions, the resulting elastomers achieve all three requirements. Generally having increased crosslink density in an elastomer will improve the tensile strength retention and shear strength retention at 80°C, but logically would expect that the tear strength retention at room temperature would be reduced. This achievement means that the compositions herein can be used as building sealants, preferably as silicone structural glazing (SSG) sealants, for example, building curtain wall applications in geographic areas with extreme climates such as high temperatures.

[0185] Such developments will be very helpful for buildings that prefer to use one-part sealants as they are more convenient for structural bonding applications of glass and metal in factory or field situations and in this case are specifically designed for use in SSGs in areas subject to extreme hot temperatures such as up to 80°C or higher.

[0186] Preferably, the composition herein is gunnable. Thus, the one-part RTV condensation-curable silicone composition as described above can be a gunnable sealant composition for:

[0187] (i) Space / gap filling applications;

[0188] (ii) Sealing applications, such as sealing the edges of lap joints in structural membranes; or

[0189] (iii) anti-fouling and weather-resistant sealants;

[0190] (iv) adhering at least two substrates together; and / or

[0191] (v) A layer laminated between two substrates to produce a laminate of the first substrate, the sealant product and the second substrate.

[0192] In the case of (v) above, when used as a layer in a laminate, the resulting laminate structure is not limited to three layers. Additional curing sealant layers and substrate layers may be applied.

[0193] In the case of a one-part RTV condensation-curable silicone composition as described above, there is provided a method for filling a space between two substrates to create a seal between the two substrates, the method comprising:

[0194] a") providing a one-part RTV condensation-curable silicone composition as described above, and

[0195] b") applying a one-part RTV condensation-curable silicone composition to a first substrate at a temperature of at least 40°C and contacting a second substrate with the silicone composition applied to the first substrate, wherein either or both of the substrates are porous substrates, or

[0196] c") filling a space formed by the arrangement of a first substrate and a second substrate with a one-part RTV condensation-curable silicone composition at a temperature of at least 40°C, wherein one or both of the substrates are porous substrates, and

[0197] d") curing the silicone composition.

[0198] The one-part RTV condensation-curable silicone composition as described above can be applied to any suitable substrate, but is particularly designed for application to substrates such as non-porous building materials such as metals (e.g., aluminum and steel) and glass, as well as porous building materials such as marble, brick, concrete, cement and other cementitious substrate combinations with this application in mind. Example

[0199] A series of examples are now provided.

[0200] Unless otherwise noted, all viscosity measurements are obtained at 25° C. Unless otherwise noted, all viscosities in the examples are measured using a Brookfield DV-III Ultra rheometer according to ASTM D4287 cone and plate method.

[0201] The compositions of Comparative Examples 1 to 4 (C.1-C.4) are provided in Table 1a and the compositions of Examples 1 to 5 (Ex. 1 to Ex. 5) are provided in Table 1b.

[0202] Table 1a: Formulations of Comparative Examples C.1 to C.4, wt. %

[0203] C.1 C.2 C.3 C.4 Polymer 1 24.81 13.62 35.48 32.25 Polymer 2 16.8 28.0 Polymer 3 9.0 Silicone resin 1 10.0 Reinforcement filler 38.0 38.0 38.0 36.0 Non-reinforcing fillers 13.0 13.0 10.0 14.0 pigment 3.0 3.0 3.0 3.0 Methyltrimethoxysilane 3.1 3.1 3.3 3.4 3-Mercaptopropyltrimethoxysilane 0.18 0.18 0.18 0.18 N-(3-(Trimethoxysilyl)propyl)ethylenediamine 0.11 0.10 0.09 0.09 catalyst 1.0 1.0 0.95 1.08

[0204] Table 1b: Formulations of Examples Ex.1 to Ex.5, wt. %

[0205] Ex.1 Ex.2 Ex.3 Ex.4 Ex.5 Polymer 1 33.43 29.25 Polymer 2 19.51 30.25 21.85 Silicone resin 2 22.2 6.0 11.1 Silicone resin 3 12.0 12.0 7.0 9.3 Reinforcement filler 33.0 38.0 33.0 33.0 36.0 Non-reinforcing fillers 17.0 13.0 17.0 17.0 14.0 pigment 2.8 3.0 3.0 3.0 Methyltrimethoxysilane 3.4 3.2 3.4 3.4 3.4 3-Mercaptopropyltrimethoxysilane 0.18 0.18 0.18 0.18 N-(3-(Trimethoxysilyl)propyl)ethylenediamine 0.09 0.11 0.09 0.09 0.09 catalyst 1.0 1.08 1.08 1.08

[0206] In Table 1a and Table 1b:

[0207] Polymer 1: Polymer 1 is a polydimethylsiloxane polymer terminated with approximately 80% (MeO)3Si-CH2-CH2-end groups and the remainder vinyl end groups, having a viscosity of approximately 60,000 mPa.s at 25°C;

[0208] Polymer 2: a polydimethylsiloxane polymer terminated with about 80% (MeO)3Si-CH2-CH2-end groups and the remainder vinyl end groups, having a viscosity of about 10,000 mPa.s at 25°C;

[0209] Polymer 3: having structure [R A d R B 3-d Si-(O-Si R 14 2) x -O]4Si branched polymer, wherein each R A is (MeO)3Si-CH2-CH2- and R B is a vinyl group and each R 14 is methyl, and the subscripts d, v, w and x are as previously described; the branched polymer has a viscosity of about 600 mPa.s at 25°C, and R A and R B About 80% of the total number of groups are R A Group;

[0210] Silicone Resin 1 mixture: an MQ resin mixture having about 0.8% vinyl groups in dimethylvinyl polydimethylsiloxane having a viscosity of about 2100 mPa.s, having about 35% by weight of dimethylvinylated and trimethylated silicone resins, the molar ratio of M units to Q units being greater than 0.1:1 and less than 1:1;

[0211] Silicone Resin 2 mixture: an MQ resin mixture initially having about 0.6% vinyl groups in dimethylvinyl polydimethylsiloxane having a viscosity of about 60,000 mPa.s at 25° C. and containing about 27% by weight of dimethylvinylated and trimethylated silicone resins, wherein about 90% of the vinyl groups have been converted to (MeO)3Si-CH2-CH2 end groups, and the molar ratio of M units to Q units is greater than 0.1:1 and less than 1:1;

[0212] Silicone resin 3 mixture: an MQ resin mixture initially having about 0.8% of vinyl groups and containing about 35% by weight of dimethylvinylated and trimethylated silicone resins in dimethylvinylpolydimethylsiloxane with a viscosity of about 2100 mPa.s (=silicone resin mixture 1), wherein about 60% of the vinyl groups have been converted into (MeO)3Si-CH2-CH2 end groups, the molar ratio of M units to Q units being greater than 0.1:1 and less than 1:1;

[0213] Precipitated calcium carbonate (PCC) filler: PCC is XTCC-201 grade commercially available from Shanxi Xintai Hengxin NanoMaterials Technology Co. Limited, Shanxi Province, China, which is treated with stearic acid and has an average particle size of 40 nm to 100 nm (data table);

[0214] Heavy calcium carbonate (GCC): GCC is Omyacarb TM 2T, which is a fine coated ground calcium carbonate (GCC) commercially available from OMYA AG;

[0215] Pigment: The pigment used was a combination of 20 wt% carbon black in dimethylhydroxy terminated polydimethylsiloxane; and

[0216] Catalyst: The catalyst used in this article is Tyzor TM PITA SM, which is an 80:20 wt % mixture of diisopropoxy-bisethylacetoacetate titanate and methyltrimethoxysilane, is commercially available from Dorf Ketal Speciality Catalysts LLC, Texas, USA.

[0217] The examples and comparative examples were prepared in a 10 liter Turello mixer (commercially available from Turellos.rl, Italy). One or more polymers, crosslinkers, catalysts and N-[3-(trimethoxysilyl)propyl]ethylenediamine were mixed together and then mixed with PCC and GCC for 20 minutes, then pigment (when present) and one or more silicone resins were introduced and mixed in, after which 3-mercaptopropyltrimethoxysilane (when present) was added and mixed in again. The resulting composition was then used immediately for testing or packaged into boxes before testing.

[0218] The composition used in each of the Examples and Comparative Examples was then cured between a glass test piece and an anodized aluminum test piece at room temperature for 28 days.

[0219] The samples were then tested for various properties in each case. The test methods used to produce the results in Table 2a are provided below:

[0220] Tack Free Time (TFT) was measured by polyethylene contact according to Dow's Corporate Test Method (CTM) 0095, and the results plotted are measured in minutes. Corporate Test (CTM) methods are publicly available from Dow Silicones upon request.

[0221] Shore A hardness was measured according to ASTM D2240-97.

[0222] The methods for determining the tensile strength, shear strength and tear strength and for preparing the required test specimens are described in EOTA-ETAG 002, November 2005.

[0223] The specimens were prepared by first thoroughly cleaning the float glass and anodized aluminum substrates with acetone and then adhering them together using the sample to be evaluated. Tensile strength (tensile rupture) tests were performed according to the method specified in 5.1.4.1.1 of EOTA-ETAG 002, November 2005. Shear strength (shear rupture) was measured according to 5.1.4.1.1 of EOTA-ETAG 002, November 2005. All tear strength (tear resistance) measurements were performed at room temperature according to the method specified in 5.1.4.6.4 of EOTA-ETAG 002, November 2005. Tensile strength retention and shear strength retention tests were performed according to the method specified in 6.1.4.1.2 of EOTA-ETAG 002, November 2005. Tear strength retention tests were performed according to the method specified in 6.1.4.6.4 of EOTA-ETAG 002, November 2005.

[0224] CF is cohesive failure. Cohesive failure occurs when the cracking leaves the adhesive layer on both surfaces, i.e. when the sealant itself breaks without separating from the substrate, adhesion failure is observed. Adhesion failure (AF) is the interfacial adhesion failure between the adhesive and the adherend. In some cases, a mixed failure mode may be observed; i.e. some areas peel off (i.e., AF), while some areas remain covered by the coating (i.e., CF). In this case, the surface portion shows CF (% CF).

[0225] Table 2a. Test results of comparative examples C1 to C.4

[0226]

[0227] Thus, as can be seen in Table 2a, even though they are comparative examples, all sealants obtained by curing the comparative example compositions C.1-4 herein provide greater than 90% cohesive failure, which is an excellent result when tested at 80°C. In addition, the crosslink density of the elastomers produced using the compositions in Table 1a was intentionally increased by using increasing amounts of low viscosity polymers (C.1 and C.2) and by using the polymer in C.3. It will be noted from Table 2a that, as expected, both the tensile strength retention and the shear strength retention at 80°C improve with increasing crosslink density of the resulting elastomer, but in each case the tear strength retention at room temperature is insufficient.

[0228] As can be seen in C.4, the use of a vinyl terminated resin in place of component (b) results in a tensile strength retention and a shear strength retention at 80°C of less than 75% of the November 2005 EOTA-ETAG 002 requirement.

[0229] Table 2b. Test results of Examples Ex.1 to Ex.5

[0230]

[0231] As shown in Ex. 1 to Ex. 5, the introduction of component (b) silicone resin results in high tensile strength retention and shear strength retention values ​​at 80°C (greater than 75%), while maintaining high tear strength retention at room temperature (above 75%), as required by the EOTA-ETAG 002 standard of November 2005. Thus, this is a surprising but practical way to prepare a one-component SSG sealant that meets the high standards required by the construction industry.

Claims

1. A one-part RTV condensation-curable silicone composition comprising the following components: (a) an organopolysiloxane polymer having the formula X 3-n R n Si-Z-(R 1 y SiO (4-y) / 2 ) z –SiR 1 2-Z-Si-R n X 3-n wherein each X is independently an alkoxy group, each R is an alkyl, alkenyl or aryl group, and each R 1 is an X group, an alkyl group, an alkenyl group or an aryl group and Z is a divalent organic group; n is 0 or 1, y is 0, 1 or 2, preferably 2, and z is an integer such that the organopolysiloxane polymer has a viscosity of 10,000 to 150,000 mPa.s at 25°C in an amount of 30 to 80% by weight of the composition; (b) an alkoxylated MQ silicone resin, optionally in the presence of a polysiloxane carrier fluid, wherein the alkoxylated MQ silicone resin has a molar ratio of M units to Q units of 0.1:1.0 to 1.0:1.0; wherein each Q-type siloxane unit has the structure SiO 4 / 2 And the M-type siloxane unit has the structure R 2 2 R 8 SiO 1 / 2 - or R 2 2 R 8 SiO 1 / 2 -and The groups exist as mixtures; Each R 2 The group is an alkyl group having 1 to 6 carbons; and R 8 is an alkenyl group having 2 to 6 carbon atoms; or R 8 For X 3-n R n Si-Z-group, wherein X, R, Z and n are all as previously defined; wherein at least 50% of R 8 The group is silicon-bonded X 3-n R n Si-Z-group; The component (b) is present in the composition in an amount of 7.5 wt % to 25 wt %; (c) one or more cross-linking agents in the form of a silicon-containing compound having at least two, alternatively at least three, hydrolyzable groups per molecule; (d) one or more reinforcing fillers selected from precipitated silica, fumed silica or precipitated calcium carbonate, the reinforcing fillers optionally being hydrophobically treated; (e) one or more silicon-containing adhesion promoters; (f) one or more condensation cure catalysts selected from catalysts comprising titanate-based compounds, zirconate-based compounds, or mixtures thereof; and optionally (g) one or more non-reinforcing fillers, said non-reinforcing fillers being capable of being treated to be hydrophobic.

2. The one-part RTV condensation-curable silicone composition of claim 1, wherein in component (a) and component (b) each n is 0 and each Z is an alkylene group having 2 to 10 carbons.

3. The one-part RTV condensation-curable silicone composition according to claim 1, wherein in component (b), at least 55% of the R 8 The group is silicon-bonded X 3-n R n Si-Z-group.

4. A one-part RTV condensation-curable silicone composition according to any preceding claim, wherein the one or more silicon-containing adhesion promoters of component (e) are selected from one or more mercaptopropyltrialkoxysilanes, aminopropyltriethoxysilanes, aminopropyltrimethoxysilanes or amines having the following structure: R 10 k (R 11 Oh) 3-k Si-Z 1 -N(H)-(CH2) m -NH2 Where R 10 is an alkyl group containing 1 to 10 carbon atoms; each R 11 can be the same or different and are H or R 10 , Z 1 is a linear or branched alkylene group having 2 to 10 carbon atoms, m is 2 to 10, and k is 0 or 1.

5. A one-part RTV condensation-curable silicone composition according to any preceding claim, wherein component (d) the reinforcing filler is precipitated calcium carbonate and component (g) is ground calcium carbonate, and the total amount of precipitated calcium carbonate + ground calcium carbonate is 30% to 60% by weight of the composition.

6. A one-part RTV condensation-curable silicone composition according to any preceding claim, wherein component (c) comprises one or more crosslinking agents comprising a crosslinking agent of formula R 9 4-f SiX' f Silicon-containing compounds and oligomerization products thereof, wherein R 9 is selected from the group consisting of hydrocarbon groups having 1 to 6 carbon atoms; X' in the above formula is a hydrolyzable group; and The subscript f is 2, 3 or 4, or the subscript f is 3 or 4.

7. A one-part RTV condensation-curable silicone composition according to any preceding claim, wherein the hydrolyzable group X' in component (c) is an alkoxy group having 1 to 6 carbon atoms.

8. The one-part RTV condensation-curable silicone composition according to any one of claims 1 to 5, wherein component (c) comprises a bipodal molecule having at least two or at least 3 alkoxysilyl terminal groups.

9. An elastomeric sealant material which is a cured product of the composition according to any one of claims 1 to 8.

10. An elastomeric sealant material, the elastomeric sealant material being obtained or being obtainable by the following steps: (i) mixing together a one-part RTV condensation-curable silicone composition according to any one of claims 1 to 8, and (ii) curing the composition.

11. An elastomeric sealant material according to claim 9 or 10 providing greater than 75% retention of tensile strength and shear strength at 80°C as measured in accordance with 6.1.4.1.2 of EOTA-ETAG 002, November 2005, while maintaining greater than 75% retention of tear strength as measured in accordance with 6.1.4.6.4 of EOTA-ETAG 002, November 2005.

12. A method for preparing an elastomeric sealant material, the method being carried out by the following steps: (i) mixing together components (a) to (g) of the one-part RTV condensation-curable silicone composition according to claims 1 to 5 and any desired additives; and (ii) curing the composition.

13. The method of preparing an elastomeric sealant material according to claim 10, wherein the one-part RTV condensation-curable silicone composition is applied to one or more substrates selected from glass, metal, stone, marble, brick, concrete, cement and other cementitious substrates and / or combinations thereof before curing.

14. Use of a one part RTV condensation curable silicone composition according to any one of claims 1 to 8 in the preparation of an elastomeric sealant material providing greater than 75% retention of tensile strength and shear strength at 80°C as measured in accordance with 6.1.4.1.2 of EOTA-ETAG 002, November 2005, while maintaining greater than 75% retention of tear strength at room temperature as measured in accordance with 6.1.4.6.4 of EOTA-ETAG 002, November 2005.

15. The use according to claim 14, wherein the resulting elastomeric sealant material is used in silicone structural glazing (SSG) applications.

16. Use of the one-part RTV condensation-curable silicone composition according to any one of claims 1 to 8 as a silicone sealant composition in silicone structural glazing (SSG) applications.

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