Sealant composition

Abstract

This relates to a one-part condensation curable silicone composition, typically a room temperature vulcanisable (RTV) silicone composition comprising a polydiorganosiloxane polymer having at least two hydrolysable groups per molecule, at least one organosilane cross-linker, one or more fillers, an organotin catalyst and one or more of a group of cure accelerating compounds of the following structures: (R10)3Si-X2 -N(H) – X2 – Si(R10)3; (R10)3Si-X2 -N(H) - (CH2)2 – N(H) – X2 – Si(R10)3; NH2 – X2 – Si(R10)3; or NH2 (CH2)2 -N(H) – X2 – Si(R10)3 where each R10 is independently a methoxy or ethoxy group and each X2 is independently a linear alkyl group having from 1 to 6 carbons; which is present in the composition in an amount of from 0.225 to 5.0 wt. % of the composition; as a co-catalyst / reaction accelerator in a one-part condensation curable silicone composition.

Description

[0001]SEALANT COMPOSITION This relates to a one-part condensation curable silicone composition, typically a room temperature vulcanisable (RTV) silicone composition comprising a polydiorganosiloxane polymer having at least two hydrolysable groups per molecule, at least one organosilane cross-linker, one or more fillers, an organotin catalyst and one or more of a group of cure accelerating compounds as a means of accelerating the cure of the composition. One-part condensation curable silicone compositions are well known and generally comprise a silicone polymer having at least two -OH or hydrolysable groups per molecule, one or more cross-linkers, fillers and often an organotin catalyst. A variety of cross-linkers may be utilised to cross-link the polymers and to form a cured sealant, preferably a cured elastomeric sealant. The cross-linkers are silicon containing materials which contain at least two or three hydrolysable groups per molecule suitable for reacting with the aforementioned polymers. The hydrolysable groups contained in the cross-linker may for example be selected from acyloxy groups (for example, acetoxy, octanoyloxy, and benzoyloxy groups); ketoximo groups); alkoxy groups (for example methoxy, ethoxy, and propoxy) and / or alkenyloxy groups (for example isopropenyloxy and 1-ethyl-2-methylvinyloxy). Sealants cured with acetoxy cross-linkers are very familiar to the user, because of the distinctive acetic acid (vinegar) aroma released during the cure process as acetic acid is a by-product of the cure process. “Acetoxy” sealants are widely used as they are known to rapidly fully cure. They strongly adhere to a wide variety of substrate surfaces. However, the fact that they release acetic acid as a by-product is a significant problem in respect of several substrates which sealants are brought into contact with because of the corrosive nature of the acetic acid. For example, the use of acetoxy cure silicone sealants can lead to discoloration of stone substrates which are used in construction applications, can cause bitumen to bleed in bituminous substrates and will potentially corrode metals such as copper and brass. As a consequence, a wide variety of “neutral” sealants have been developed which, whilst they generally take longer to cure do not form such corrosive by-products, allowing them to be used with a wide range of substrates without the corrosive effects caused by acetic acid. Of these perhaps the most commonly used are sealant compositions which rely on oxime cross-linking agents or alkoxy cross-linking agents to cross-link the polymers during cure. Most oxime sealants release methyl ethyl ketoxime (MEKO) (sometimes referred to as butan-2-one oxime) as a by-product during cure whilst the alkoxy cure sealants tend to release alcoholic by-products. Both of these sealants are widely used in exterior applications for e.g., weather resistant applications with oxime silicone sealants having the advantage of being generally faster curing compared with alkoxy silicone sealants. However, environmental and health concerns over the release of MEKO during the cure of oxime sealants are leading further effort towards the development and improvement of alternative neutral sealants one problem being the inferior cure speeds of neutral sealant compositions containing alkoxy cross-linkers and organotin catalysts. An obvious means of accelerating the cure of such sealants might well appear to be increasing the content of the organotin catalysts in such compositions but this is undesirable, not least because the presence of the residual tin catalysts in the resulting cured sealants tends to cause reversion leading to sealant failure, especially when high concentrations of tin remain after the sealant have cured. There is provided herein a one-part condensation curable silicone composition comprising: (a) an organopolysiloxane polymer having an average of at least two silicon-bonded hydrolysable groups per molecule; and a viscosity of from 750 to 150,000mPa.s at 25oC, (b) One or more reinforcing fillers, one or more non-reinforcing fillers or a mixture thereof; (c) an organotin condensation catalyst in an amount of from 0.001 to 1.0 wt. % of the composition; (d) one or more organosilane cross-linkers having at least two alkoxy groups, alternatively at least three alkoxy groups, per molecule; and (e) a co-catalyst / reaction accelerator selected from one or more amino organosilicon compounds of the following structures: (R10)3Si-X2-N(H) – X2– Si(R10)3; (R10)3Si-X2-N(H) - (CH2)2 – N(H) – X2– Si(R10)3; NH2 – X2– Si(R10)3; or NH2 (CH2)2 -N(H) – X2– Si(R10)3 where each R10is independently a methoxy or ethoxy group and each X2is independently a linear alkyl group having from 1 to 6 carbons; which is present in the composition in an amount of from 0.225 to 5.0 wt. % of the composition. There is also provided a method of accelerating cure of a one-part condensation curable silicone composition comprising introducing one or more co-catalyst / reaction accelerator(s) selected from one or more amino organosilicon compounds of the following structures (R10)3Si-X2-N(H) – X2– Si(R10)3; (R10)3Si-X2-N(H) - (CH2)2– N(H) – X2– Si(R10)3; NH2– X2– Si(R10)3; or NH2 (CH2)2 -N(H) – X2– Si(R10)3 where each R10is independently a methoxy or ethoxy group and each X2is independently a linear alkyl group having from 1 to 6 carbons; which is present in the composition in an amount of from 0.225 to 5.0 wt. % of the composition; into a one-part condensation curable silicone composition otherwise comprising (a) an organopolysiloxane polymer having an average of at least two silicon-bonded hydrolysable groups per molecule; and a viscosity of from 750 to 150,000mPa.s at 25oC, (b) One or more reinforcing fillers, one or more non-reinforcing fillers or a mixture thereof; (c) an organotin condensation catalyst in an amount of from 0.001 to 1.0 wt. % of the composition; and (d) one or more silane cross-linkers having at least two alkoxy groups, alternatively at least three alkoxy groups, per molecule; and curing the composition. There is also provided a cured silicone product which is the cured product of the above composition or is the product resulting from the method described above. There is also provided a use of a co-catalyst / reaction accelerator selected from one or more amino organosilicon compounds of the following structures: (R10)3Si-X2-N(H) – X2– Si(R10)3; (R10)3Si-X2-N(H) - (CH2)2 – N(H) – X2– Si(R10)3; NH2– X2– Si(R10)3; or NH2(CH2)2-N(H) – X2– Si(R10)3where each R10is independently a methoxy or ethoxy group and each X2is independently a linear alkyl group having from 1 to 6 carbons; which is present in the composition in an amount of from 0.225 to 5.0 wt. % of the composition; to accelerate the cure of a one-part condensation curable silicone composition; wherein said one-part condensation curable silicone composition otherwise comprises: (a) an organopolysiloxane polymer having an average of at least two silicon-bonded hydrolysable groups per molecule; and a viscosity of from 750 to 150,000mPa.s at 25oC, (b) One or more reinforcing fillers, one or more non-reinforcing fillers or a mixture thereof; (c) an organotin condensation catalyst in an amount of from 0.001 to 1.0 wt. % of the composition; and (d) one or more organosilane cross-linkers having at least two alkoxy groups, alternatively at least three alkoxy groups, per molecule. There is also provided a use of the aforementioned one-part condensation curable silicone composition as a sealant in construction applications such as in facade, insulated glass, and window and door construction applications. The concept of “comprising” where used herein is used in its widest sense to mean and to encompass the notions of “include” and “consist of”. The compositions described above are preferably room temperature vulcanisable (RTV) compositions in that they cure at room temperature without heating but may, if deemed appropriate, have cure accelerated by heating. The total amount of any composition provided in terms of wt. % is 100 wt. %. It was unexpectedly found that when included in the formulation at low doses, e.g., 0.225 to 5.0 wt. % of the composition, component (e) substantially decreased the cure time of the sealant compared to when using a standard amount of an organotin catalyst (component (c). Thus, the introduction of component (e) into such sealant compositions can allow for the preparation of sealants with very fast cure times to match or outperform fast cure oxime sealant compositions. Alternatively, the introduction of component (e) can allow for a decrease in the content of organotin catalysts (component (c) in the composition thereby maintaining good surface cure while obtaining improved performance (stability, adhesion, shelf life in view of the reduction in the organotin catalyst component (c). The one-part condensation curable silicone composition provided herein comprises the following components: Component (a): an organopolysiloxane polymer having an average of at least two silicon-bonded hydrolysable groups per molecule Component (a) may be any suitable organopolysiloxane polymer having an average of at least two silicon-bonded hydrolysable groups per molecule and a viscosity of from 750 to 150,000mPa.s at 25oC; alternatively, any suitable organopolysiloxane polymer having at least two silicon-bonded hydrolysable groups per molecule and a viscosity of from 750 to 150,000mPa.s at 25oC. The silicon bonded hydrolysable groups may be, but are not necessarily, terminal groups. In one embodiment, the silicon bonded hydrolysable groups are alkoxy groups having from one to 10 carbons. Illustrative alkoxy groups are methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, t-butoxy, isobutoxy, pentoxy, hexoxy and 2- ethylhexoxy; dialkoxy groups, such as methoxymethoxy or ethoxymethoxy an alkoxyaryloxy, such as ethoxyphenoxy groups. Alternatively, the alkoxy groups may contain from 1 to 6 carbons i.e., a methoxy, ethoxy, propoxy, isopropoxy, n-butoxy or t-butoxy group. For example, the organopolysiloxane polymer having an average of at least two silicon-bonded hydrolysable groups per molecule (a), of the one-part condensation curable silicone composition described herein, may have the formula: X3-nRnSi-Z- (R1ySiO(4-y) / 2)z –SiR12 -Z-Si-RnX3-n (1) in which each X is independently an alkoxy group, each R is an alkyl, alkenyl or aryl group, each R1is an alkoxy group, an alkyl group, an alkenyl group or an aryl group and Z is oxygen or a divalent organic group, typically containing from 2 to 10 carbons; each n is independently 0, 1, 2 or 3, y is 0, 1 or 2, preferably 2 and z is an integer consistent with said organopolysiloxane polymer having a viscosity of from 750 to 150,000mPa.s at 25oC. In the above formula each X is independently an alkoxy group, alternatively an alkoxy group having from 1 and 10 carbons. Illustrative alkoxy groups are methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, t- butoxy, isobutoxy, pentoxy, hexoxy and 2-ethylhexoxy; dialkoxy groups, such as methoxymethoxy or ethoxymethoxy an alkoxyaryloxy, such as ethoxyphenoxy groups; alternatively, each X is an alkoxy group having from one and six carbons, alternatively having from one and four carbons i.e., methoxy, ethoxy, propoxy, isopropoxy, n-butoxy or t-butoxy group or alternatively is a methoxy or ethoxy group. Each R group is an alkyl, alkenyl or aryl group, alternatively each R is an alkyl group having from 1 to 6 carbons, an alkenyl group having from 2 to 6 carbons such as vinyl, allyl and hexenyl groups or an aryl group having from 6 to 12 carbons; alternatively, each R is an alkyl group having from 1 to 6 carbons, or an aryl group having from 6 to 12 carbons; alternatively each R is an alkyl group having from 1 to 6 carbons, alternatively each R is an ethyl group or a methyl group. In one embodiment R may include substituted aliphatic organic groups such as 3,3,3-trifluoropropyl groups aminoalkyl groups, polyaminoalkyl groups, and / or epoxyalkyl groups. Each R1is an alkoxy group, alkyl group, alkenyl group or aryl group. For the avoidance of doubt this means that cumulatively at least two X groups, at least two R1groups or at least one X group and one R1group per molecule are alkoxy groups. It is possible that some R1groups may be siloxane branches off the polymer backbone which branches may have terminal X groups as hereinbefore described. Each Z may be the same of different and is oxygen or a divalent organic group. When Z is a divalent organic group, it is typically an alkylene having from 2 to 10 carbons, such as for example, an ethylene, propylene, butylene, pentylene and / or hexylene group; alternatively, an alkylene group having 2 to 6 carbons, alternatively an alkylene group having from 2 to 5 carbons. The alkylene group may contain branching. Each subscript n is zero 1, 2 or 3, alternatively each subscript n is 0, 1 or 2, alternatively each subscript n is 0 or 1. In one embodiment each n is zero and each Z is an alkylene having from 2 to 10 carbons. Each subscript y is 0, 1 or 2, and is preferably 2. Whilst y is 0, 1 or 2, substantially y= 2, e.g., at least 90%, alternatively 95% of R1ySiO(4-y) / 2groups are characterized with y = 2. Subscript z is an integer such that said organopolysiloxane polymer has a viscosity of from 750 to 150,000mPa.s at 25oC therefore z is an integer of from approximately 50 to 2000. Preferably, z is from about 70 to 1000. The Degree of Polymerization (DP), (i.e., in the above formula substantially z), is usually defined as the number of monomeric units in a macromolecule or polymer or oligomer molecule of silicone. Synthetic polymers invariably consist of a mixture of macromolecular species with different degrees of polymerization and therefore of different molecular weights. There are different types of average polymer molecular weight, which can be measured in different experiments. The two most important are the number average molecular weight (Mn) and the weight average molecular weight (Mw). The Mn and Mw of a silicone polymer can be determined by gel permeation chromatography (GPC) with precision of about 10-15% using polystyrene standards. This technique is standard and yields Mw, Mn and polydispersity index (PI). The degree of polymerization (DP) =Mn / Mu where Mn is the number-average molecular weight coming from the GPC measurement and Mu is the molecular weight of a monomer unit. PI=Mw / Mn. The DP is linked to the viscosity of the polymer via Mw, 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 may, for example, be determined using a Waters 2695 Separations Module equipped with a vacuum degasser, and a Waters 2414 refractive index detector (Waters Corporation of MA, USA). The analyses may then be performed using certified grade toluene flowing at 1.0 mL / min as the eluent. Data collection and analyses may be performed using Waters Empower GPC software. The viscosity of component (a) is from 750 to 150,000mPa.s at 25oC, alternatively from 1000 to 125,000mPa.s at 25oC, alternatively 10,000 to 100,000mPa.s at 25oC, alternatively 20,000 to 80,000mPa.s at 25oC. The viscosity of component (a) may be measured at 25oC in accordance with the ASTM D4287 Cone and Plate Method using a Brookfield DV-III Ultra Rheometer. Alternatively the viscosity can be measured using a Brookfield DV-II Viscometer in accordance with ASTM D2196 using Spindle 4 at 6 rpm. The organopolysiloxane polymer (a) described above is present in the one-component room temperature vulcanizable (RTV) silicone sealant composition in an amount of from 30 to 90 weight % (wt. %) of the composition. Alternatively, 30 to 80 wt. % of the composition alternatively 35 to 80 wt. % of the composition. Organopolysiloxane polymer (a) can be a single siloxane represented by Formula (1) or it can be mixtures of organopolysiloxane polymers represented by the aforesaid formula. Hence, it may be a "siloxane polymer mixture" so organopolysiloxane polymer (a) is meant to include any individual organopolysiloxane polymer (a) or mixtures of organopolysiloxane polymer (a). Component (b) One or more reinforcing fillers, one or more non-reinforcing fillers or a mixture thereof Component (b) is one or more reinforcing fillers, one or more non-reinforcing fillers or a mixture thereof. The one or more reinforcing fillers which are or may be present in the composition as component (b) herein may for example be selected from precipitated silica, fumed silica, precipitated calcium carbonate, or a mixture of two or more thereof. Typically, the surface area of the reinforcing filler (b) is at least 15 m² / g in the case of precipitated calcium carbonate measured in accordance with the BET method (ISO 9277: 2010), alternatively 15 to 50 m² / g, alternatively 15 to 25 m² / g. Silica reinforcing fillers have a typical surface area of at least 50 m² / g in accordance with the BET method (ISO 9277: 2010). In the case of high surface area fumed silica and / or high surface area precipitated silica, these may have surface areas of from 75 to 400 m² / g measured in accordance with the BET method (ISO 9277: 2010), alternatively of from 100 to 300 m² / g in accordance with the BET method (ISO 9277: 2010). The reinforcing fillers (b) may be hydrophobically treated for example with one or more aliphatic acids, e.g., a fatty acid such as stearic acid or a fatty acid ester such as a stearate, or with organosilanes, organosiloxanes, or organosilazanes hexaalkyl disilazane or short chain siloxane diols to render the filler(s) hydrophobic and therefore easier to handle and obtain a homogeneous mixture with the other adhesive components. Specific examples organosilanes, organosiloxanes, or organosilazanes may include, but are not restricted to, silanol terminated trifluoropropylmethylsiloxane, silanol terminated vinyl methyl (ViMe) siloxane, silanol terminated methyl phenyl (MePh) siloxane, liquid hydroxyldimethyl-terminated polydiorganosiloxane containing an average from 2 to 20 repeating units of diorganosiloxane in each molecule, hydroxyldimethyl terminated phenylmethyl Siloxane, hexaorganodisiloxanes, such as hexamethyldisiloxane, divinyltetramethyldisiloxane; hexaorganodisilazanes, such as hexamethyldisilazane (HMDZ), divinyltetramethyldisilazane and tetramethyldi(trifluoropropyl)disilazane; hydroxyldimethyl terminated polydimethylmethylvinyl siloxane, octamethyl cyclotetrasiloxane, and silanes including but not limited to methyltrimethoxysilane, dimethyldimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, chlorotrimethyl silane, dichlorodimethyl silane, trichloromethyl silane. The surface treatment of the fillers makes them easily wetted by component (a). These surface modified fillers are preferably in a finely divided form and do not clump and can be homogeneously incorporated into the silicone polymer (a). This results in improved room temperature mechanical properties of the uncured compositions. The fillers may be pre-treated or may be treated in situ when being mixed with component (a). A small amount of water can be added together with the silica treating agent(s) as processing aid. Depending on the filler(s) chosen the reinforcing fillers of component (b) may be present in an amount of from 2.5 to 60 wt. % of the composition. In the case when the selected fillers are precipitated silica and / or fumed silica or a combination thereof the inorganic fillers (b) are present in a range of from about 5.0 to 35 wt. % of the composition, alternatively of from 5 to 30 wt. % of the composition, alternatively of from 5 to 25 wt. % of the composition. However, when reinforcing filler of component (b) is precipitated calcium carbonate, the composition will tend to include a larger wt. % of the composition, e.g., from 10 to 60 wt. % of the composition, alternatively of from 30 to 60 wt. % of the composition, alternatively of from 35 to 55 wt. % of the composition. When component (b) is a mixture of silica and precipitated calcium carbonate the wt. % will typically somewhere therebetween. Non-reinforcing fillers The one or more non-reinforcing fillers which are or may be present in the composition as component (b) herein, may be selected from one or more of the following aluminite, calcium sulphate (anhydrite), gypsum, nepheline, syenite, ground calcium carbonate, quartz, calcium sulphate, magnesium carbonate, clays such as kaolin, aluminium trihydroxide, magnesium hydroxide (brucite), graphite, copper carbonate, e.g., malachite, nickel carbonate, e.g., zarachite, barium carbonate, e.g., witherite and / or strontium carbonate e.g., strontianite. Silicates from the group consisting of olivine group; garnet group; aluminosilicates; ring silicates; chain silicates; and sheet silicates. The olivine group comprises silicate minerals, such as but not limited to, forsterite and Mg2SiO4. The garnet group comprises ground silicate minerals, such as but not limited to, pyrope; Mg3Al2Si3O12; grossular; and Ca2Al2Si3O12. Aluminosilicates comprise ground silicate minerals, such as but not limited to, sillimanite; Al2SiO5; mullite; 3Al2O3.2SiO2; kyanite; and Al2SiO5. The ring silicates group comprises silicate minerals, such as but not limited to, cordierite and Al3(Mg,Fe)2[Si4AlO18]. The chain silicates group comprises ground silicate minerals, such as but not limited to, wollastonite and Ca[SiO3]. The sheet silicates group comprises silicate minerals, such as but not limited to, mica; K2AI14[Si6Al2O20](OH)4; pyrophyllite; Al4[Si8O20](OH)4; talc; Mg6[Si8O20](OH)4; serpentine for example, asbestos; Kaolinite; Al4[Si4O10](OH)8; and vermiculite. The non-reinforcing fillers of component (b), when present, may also be hydrophobically treated as described above. And when present may be present in amounts up to about 60 wt. % of the composition but typically are found in lower amounts in combination with some reinforcing filler. Component (c) an organotin condensation catalyst in an amount of from 0.001 to 1.0 wt. % of the composition Component (c), the organotin condensation catalyst may be any suitable organotin condensation catalyst. Examples of suitable organotin condensation catalysts include tin triflates, dialkyltin compounds, selected from dimethyltin di-2-ethylhexanoate, dimethyltin dilaurate, di-n-butyltin diacetate (DBTDA), di-n-butyltin di-2-ethylhexanoate, dimethyltin dineodecanoate (DMTDN), dioctyltin dineodecanoate (DOTDN), di-n-butyltin dicaprylate, di-n-butyltin di-2,2-dimethyl octanoate, di-n-butyltin octanoate, di- n- butyltin dilaurate (DBTDL), di-n-butyltin distearate, di-n-butyltin dimaleate, di-n-butyltin dioleate, di- n-octyltin di-2-ethylhexanoate, di-n-octyltin di-2,2-dimethyl octanoate, di-n-octyltin dimaleate, dipropyl tin bis(acetylacetonate), dibutyl tin bis(acetylacetonate), dipentyl tin bis(acetylacetonate), dihexyl tin bis(acetylacetonate), dioctyl tin bis(acetylacetonate), didecyl tin bis(acetylacetonate), didodecyl tin bis(acetylacetonate), di-n-octyl tin dilaurate (DOTDL), di-n-butyl tin oxide, carbomethoxyphenyl tin trisuberate, tin butyrate, butyltintri-2-ethylhexoate, tin naphthenate, isobutyltin triceroate, tin octoate, triethyltin tartrate and di-n-octyl tin oxide. Said organotin condensation catalyst of component (c) herein is present in an amount of from 0.001 to 1.0 wt. % of the composition, alternatively from 0.01 to 0.75 wt.% of the composition, alternatively 0.05 to 0.5 wt.% of the composition, alternatively 0.05 to 0.25 wt.% of the composition, Component (d): One or more organosilane cross-linkers having at least two alkoxy groups, alternatively at least three alkoxy groups, per molecule. Component (d) is one or more organosilane cross-linkers having at least two alkoxy groups, alternatively at least three alkoxy groups, per molecule. Component (d) as defined herein does not include any amine groups and the term “organosilanes” is considered to incorporate tetraalkoxysilanes. but does not include any compounds with an -Si-O-Si siloxane linkage. Component (d) is effectively functioning as a cross-linker and as such requires a minimum of 2 alkoxy groups per molecule and preferably 3 or more. Component (d) may have two alkoxy groups when component (a) has three or more hydrolysable groups per molecule. Component (d) may thus have two but alternatively has three or more silicon-bonded alkoxy groups per molecule which are reactive with the hydrolysable groups in component (a). Typically, component (d) may be: - one or more organosilanes having at least 2 alkoxy groups, alternatively at least 3 alkoxy groups per molecule group; and / or - one or more silyl functional molecules having at least 2 silyl groups, each silyl group containing at least one alkoxy group. For the sake of the disclosure herein a disilyl functional molecule comprises two silicon atoms each having at least one hydrolysable group, where the silicon atoms are separated by an organic chain and do not contain any -Si-O-Si- linkages. Typically, each silyl group on the disilyl functional molecule are terminal groups. The organic chain may be a polymeric chain such as an alkylene chain having from 2 to 10 carbons. The alkoxy groups on the silyl groups may be selected from alkoxy groups (for example methoxy, ethoxy, and propoxy) and alkenyloxy groups (for example isopropenyloxy and 1-ethyl-2- methylvinyloxy). Alternatively, said hydrolysable groups on the silyl groups are selected from alkoxy groups and / alkenyloxy groups. When component (d) is an organosilane, said organosilanes may include alkoxy functional organosilanes, including tetraalkoxysilanes. Preferably, when component (d) is an organosilane, said organosilanes may include alkoxy functional organosilanes, When component (d) is an organosilane and when the organosilane has only three silicon-bonded alkoxy groups per molecule, the fourth group is suitably a non-hydrolysable silicon-bonded organic group. These silicon-bonded organic groups are suitably hydrocarbyl groups which are optionally substituted by halogen such as fluorine and chlorine. Examples of such fourth groups include alkyl groups (for example methyl, ethyl, propyl, and butyl); cycloalkyl groups (for example cyclopentyl and cyclohexyl); alkenyl groups (for example vinyl and allyl); aryl groups (for example phenyl, and tolyl); aralkyl groups (for example 2-phenylethyl) and groups. A typical organosilane of component (d) may be described by formula (8) R"4-rSi(R5)r(8) wherein R5is an alkoxy group, R” is an alkyl groups (for example methyl, ethyl, propyl, and butyl); cycloalkyl groups (for example cyclopentyl and cyclohexyl); alkenyl groups (for example vinyl and allyl); aryl groups (for example phenyl, and tolyl); aralkyl groups (for example 2-phenylethyl).and r has a value of 2, 3 or 4. In formula (8) R5is a suitable alkoxy group as defined as X above, for example an alkoxy group having from 1 and 10 carbons. Illustrative alkoxy groups are methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, t- butoxy, isobutoxy, pentoxy, hexoxy and 2-ethylhexoxy; dialkoxy groups, such as methoxymethoxy or ethoxymethoxy an alkoxyaryloxy, such as ethoxyphenoxy groups; alternatively, each R5is an alkoxy group having from one and six carbons, alternatively having from one and four carbons i.e., methoxy, ethoxy, propoxy, isopropoxy, n-butoxy or t-butoxy group or alternatively is a methoxy or ethoxy group; and R” is selected from an alkyl group, cycloalkyl groups; alkenyl group, aryl group or aralkyl group. In one embodiment R” is an alkyl group having from 1 to 6 carbons, such as methyl, ethyl, propyl, isopropyl, n- butyl and t-butyl; cyclopentyl and cyclohexyl; an alkenyl group having from 2 to 6 carbons such as vinyl and allyl; a phenyl, and tolyl or 2-phenylethyl). In one embodiment R” represents methyl, ethyl or vinyl or isopropyl or t-butyl. In a further embodiment component (d) is a silyl functional molecule having at least 2 silyl groups each having at least 1 and up to 3 hydrolysable groups, alternatively each silyl group has at least 2 hydrolysable groups. Component (d) may be a disilyl functional polymer, that is, a polymer backbone having two silyl groups, each containing at least one alkoxy group with the backbone being a polyether or alkylene backbone. Component (d) thus include alkyltrialkoxysilanes such as methyltrimethoxysilane (MTM) and methyltriethoxysilane, tetraethoxysilane, partially condensed tetraethoxysilane, alkenyltrialkoxy silanes such as vinyltrimethoxysilane and vinyltriethoxysilane, isobutyltrimethoxysilane (iBTM). Other suitable silanes include ethyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, 1,6- bis(trimethoxysilyl)hexane (comparative 4 in the examples below). The component (d) used may also comprise any combination of two or more of the above. Said one or more organosilane cross-linkers having at least 3 hydroxyl and / or hydrolysable groups per molecule (d), when present, may be selected from an organosilane having the structure R8j Si(OR5)4-j As mentioned previously where each R5may be the same or different and is hydrogen or an alkyl group containing at least one carbons, alternatively from 1 to 20 carbons, alternatively from 1 to 10 carbons alternatively from 1 to 6 carbons. The value of j is 0 or 1. Whilst each R5group may be the same of different it is preferred that at least two R5groups are the same, alternatively at least three R5groups are the same and alternatively when j is 0 all R5groups are the same. Hence, specific examples of the reactive organosilane (d) when j is zero include tetraethylorthosilicate, When j is 1 the group R8is present. R8is a silicon-bonded organic group selected from straight or branched monovalent hydrocarbon group having at least one carbon, a cycloalkyl group, an aryl group, or an aralkyl group. The unsubstituted monovalent hydrocarbon groups, suitable as R8, may include alkyl groups e.g., methyl, ethyl, propyl, and other alkyl groups, alkenyl groups such as vinyl, cycloalkyl groups may include cyclopentane groups and cyclohexane groups. Specific examples of suitable organosilane cross-linkers (d), include but are not limited to vinyltrimethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane, ethyltrimethoxysilane, propyltriethoxysilane, isobutyltriethoxysilane, isobutyltrimethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, methyltris(isopropenoxy)silane or vinyltris(isopropenoxy)silane. The organosilane cross-linkers (d) is present in an amount of from 0.1 to 25 % by weight (wt. %) of the composition, alternatively from 0.1 to 15% by weight of the composition, alternatively present in an amount of from 0.5 to 10% by weight of the composition, alternatively in an amount of from 0.75 to 3.5% by weight of the composition. Component (d) and component (e) are different. Component (e) co-catalyst / reaction accelerator The co-catalyst / reaction accelerator (e) in the one-part condensation curable silicone composition is one or more amino organosilicon compounds of the following structures (R10)3Si-X2-N(H) – X2– Si(R10)3; (R10)3Si-X2-N(H) - (CH2)2– N(H) – X2– Si(R10)3; NH2– X2– Si(R10)3; or NH2 (CH2)2 -N(H) – X2– Si(R10)3 where each R10is independently a methoxy or ethoxy group, alternatively a methoxy group, each X2is independently a linear or branched alkyl group having from 1 to 6 carbons such as methyl, ethyl, n- propyl, n-butyl, n-pentyl, isopropyl and tertiary butyl. Component (e) is present in the composition in an amount of from 0.225 to 5.0 wt. % of the composition, alternatively from 0.225 to 4.0 wt. % of the composition, alternatively from 0.225 to 3.0 wt. % of the composition. Where the amino organosilicon compounds have the structure (R10)3Si-X2-N(H) – X2– Si(R10)3 specific examples include bis (3-trimethoxysilylpropyll)amine, and bis (3-triethoxysilylpropyll)amine. Where the amino organosilicon compounds have the structure (R10)3Si-X2-N(H) - (CH2)2 – N(H) – X2– Si(R10)3 specific examples include N,N’-bis[(3-trimethoxysilyl)alkyl]ethylenediamine, and N,N’-bis[(3- triethoxysilyl)alkyl]ethylenediamine. Where the amino organosilicon compounds have the structure NH2 – X2– Si(R10)3 specific examples include 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane. Where the amino organosilicon compounds have the structure NH2(CH2)2-N(H) – X2– Si(R10)3specific examples include 3-(2-aminoethyl)aminopropyltrimethoxysilane and 3-(2- aminoethyl)aminopropyltrimethoxysilane. When present in component (e) some alkoxy groups may participate in cross-linking activities with components(a) and (d). Optional Additives The one-part condensation curable silicone composition as hereinbefore described may comprise a variety of additives. The additives may include, but are not limited to, alternative adhesion promoters, rheological modifiers, water / moisture scavengers, plasticizers and / or extenders, pigments & colorants, antioxidants, UV and / or light stabilizers and biocides. Additional adhesion promoters Any additional suitable adhesion promoter(s) may be utilised in the one-part condensation curable silicone composition as hereinbefore described. These may include alkoxysilanes of the formula R14hSi(OR15)(4-h)where subscript h is 1, 2, or 3, alternatively h is 3. Each R14is independently a monovalent organofunctional group selected from an epoxy functional group such as glycidoxypropyl or (epoxycyclohexyl)ethyl, i.e., 3-glycidoxypropyltrimethoxysilane, 2-(3,4- epoxycyclohexyl)ethyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane; an amino functional group such as aminoethylaminopropyl or aminopropyl, i.e., 3-aminopropyltriethoxysilane, a methacryloxypropyl, a mercapto functional group such as mercaptopropyl or an unsaturated organic group. Each R15is independently an unsubstituted, saturated hydrocarbon group of at least 1 carbon atom. R15may have 1 to 4 carbon atoms, alternatively 1 to 2 carbon atoms. R15is exemplified by methyl, ethyl, n-propyl, and iso- propyl. Alternatively, the optional adhesion promoter may be selected from one or more mercaptopropyltrialkoxysilanes, an aminopropyltriethoxysilane, an aminopropyltrimethoxysilane, and isocyanurates containing silicon groups such as 1, 3, 5-tris(trialkoxysilylalkyl) isocyanurates e.g., tris(trimethoxypropyl)isocyanurate and the like. Further optional adhesion promoters include, for the sake of example but are not limited to reaction products of ethylenediamine with silylacrylates as well as reaction products of epoxyalkylalkoxysilanes such as 3-glycidoxypropyltrimethoxysilane with amino-substituted alkoxysilanes such as 3- aminopropyltrimethoxysilane and optionally with alkylalkoxysilanes such as methyltrimethoxysilane. The adhesion promoter when present is present in an amount of from 0.05 to 3.75% by weight of the composition, alternatively, in an amount of 0.05- 2.5 % by weight of the composition, alternatively, in an amount of 0.05- 2.0 % by weight of the composition, alternatively, in an amount of 0.05 to 1.0 % by weight of the composition. Rheology modifiers Rheology modifiers which may be incorporated in the one-part condensation curable silicone composition as described above include silicone organic co-polymers such as those described in EP0802233 based on polyols of polyethers or polyesters; non-ionic surfactants selected from the group consisting of polyethylene glycol, polypropylene glycol, ethoxylated castor oil, oleic acid ethoxylate, alkylphenol ethoxylates, copolymers or ethylene oxide and propylene oxide, and silicone polyether copolymers; as well as silicone glycols. For some systems these rheology modifiers, particularly copolymers of ethylene oxide and propylene oxide, and silicone polyether copolymers, may enhance the adhesion to substrates, particularly plastic substrates. Moisture / water scavenger Any suitable -OH (moisture / water / alcohol) scavenger may be used in the one-part condensation curable silicone composition when required given catalyst (c) is an organotin catalyst. These may be selected from, for example, orthoformic acid esters, molecular sieves and / or, silazanes e.g., organosilazanes such as hexaalkyl disilazane, e.g., hexamethyldisilazane (HMDZ). One or more plasticizer(s), one or more extender(s) or a mixture thereof The one-part condensation curable silicone composition as described above may also include one or more plasticizer(s), one or more extender(s) or a mixture thereof (g). These may be in the form of silicone or organic fluids which are unreactive with any of components (a) or (c) to (e) above. If present the plasticizer or extender content will be present in an amount of from 5 to 30 wt. % of the composition, alternatively from 5 to 10 wt. % or the composition. Examples of non-reactive silicone fluids useful as plasticizers include polydiorganosiloxanes such as polydimethylsiloxane having terminal triorganosiloxy groups wherein the organic substituents are, for example, methyl, vinyl or phenyl or combinations of these groups. Such polydimethylsiloxanes can for example have a viscosity of from about 5 to about 100,000 mPa.s at 25oC (measured as described above). Alternatively compatible organic plasticisers may be utilised additionally to or instead of the silicone fluid plasticiser. These may include dialkyl phthalates wherein the alkyl group may be linear and / or branched and contain from six to 20 carbon atoms such as dioctyl, dihexyl, dinonyl, didecyl, diallanyl and other phthalates, and analogous adipate, azelate, oleate and sebacate esters; polyols such as ethylene glycol and its derivatives; and organic phosphates such as tricresyl phosphate and / or triphenyl phosphates. Examples of extenders for use in compositions herein include mineral oil based (typically petroleum based) paraffinic hydrocarbons, mixtures of paraffinic and naphthenic hydrocarbons, paraffin oils comprising cyclic paraffins and non-cyclic paraffins and hydrocarbon fluids containing naphthenics, polycyclic naphthenics and paraffins, or polyalkylbenzenes such as heavy alkylates (alkylated aromatic materials remaining after distillation of oil in a refinery). Examples of such extenders are discussed in GB2424898 the content of which is hereby enclosed by reference. Pigments and / or colorants The one-part condensation curable silicone composition as described above may further comprise one or more pigments and / or colorants. The pigments and / or colorants may be coloured, white, black, metal effect, and luminescent e.g., fluorescent or phosphorescent. Pigments are utilized to colour the composition as required. Any suitable pigment may be utilized providing it is compatible with the composition herein. Suitable white pigments and / or colorants include titanium dioxide, zinc oxide, lead oxide, zinc sulfide, lithophone, zirconium oxide, and antimony oxide. Suitable non-white inorganic pigments and / or colorants include, but are not limited to, iron oxide pigments such as goethite, lepidocrocite, hematite, maghemite, and magnetite black iron oxide, yellow iron oxide, brown iron oxide, and red iron oxide; 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 chromium yellow, molybdate red, and molybdate orange; ultramarine pigments; cobalt oxide pigments; nickel antimony titanates; lead chrome; carbon black (when present, carbon black will function as both a non-reinforcing filler and colorant); lampblack, and metal effect pigments such as aluminium, copper, copper oxide, bronze, stainless steel, nickel, zinc, and brass. Suitable organic non-white pigments and / or colorants include phthalocyanine pigments, e.g., phthalocyanine blue and phthalocyanine green; monoarylide yellow, diarylide yellow, benzimidazolone yellow, heterocyclic yellow, DAN orange, quinacridone pigments, e.g., quinacridone magenta and quinacridone violet; organic reds, including metallized azo reds and nonmetallized azo reds and other azo pigments, monoazo pigments, diazo pigments, azo pigment lakes, β-naphthol pigments, naphthol AS pigments, benzimidazolone pigments, diazo condensation pigment, isoindolinone, and isoindoline pigments, polycyclic pigments, perylene and perinone pigments, thioindigo pigments, anthrapyrimidone pigments, flavanthrone pigments, anthanthrone pigments, dioxazine pigments, triarylcarbonium pigments, quinophthalone pigments, and diketopyrrolo pyrrole pigments. Typically, the pigments and / or colorants, when particulates, have average particle diameters in the range of from 10 nm to 50 µm, preferably in the range of from 40 nm to 2 µm. The pigments and / or colorants when present are present in the range of from 2, alternatively from 3, alternatively from 5 to 20 wt. % of the composition. Antioxidant Any suitable antioxidant(s) may be utilised, if deemed required. Examples may include: ethylene bis (oxyethylene) bis(3-tert-butyl-4-hydroxy-5(methylhydrocinnamate) 36443-68-2; tetrakis[methylene(3,5- di-tert-butyl-4-hydroxy hydrocinnamate)]methane 6683-19-8; octadecyl 3,5-di-tert-butyl-4- hydroxyhyrocinnamate 2082-79-3; N,N’-hexamethylene-bis (3,5-di-tert-butyl-4- hydroxyhyrocinnamamide) 23128-74-7; 3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid,C7-9 branched alkyl esters 125643-61-0; N-phenylbenzene amine, reaction products with 2,4,4-trimethylpentene 68411- 46-1; e.g., anti-oxidants sold under the Irganox®name from BASF. UV and / or light stabilizers UV and / or light stabilizers may include, for the sake of example include benzotriazole, ultraviolet light absorbers and / or hindered amine light stabilizers (HALS) such as the TINUVIN®product line from Ciba Specialty Chemicals Inc. Biocides Biocides may additionally be utilized in the one-part condensation curable silicone composition if required. It is intended that the term “biocides” includes bactericides, fungicides and algicides, and the like. Suitable examples of useful biocides, which may be utilized in compositions as described herein, include, for the sake of example: Carbamates such as methyl-N-benzimidazol-2-ylcarbamate (carbendazim) and other suitable carbamates, 10,10’-oxybisphenoxarsine, 2-(4-thiazolyl)-benzimidazole, N-(fluorodichloromethylthio)phthalimide, diiodo methyl p-tolyl sulfone, if appropriate in combination with a UV stabilizer, such as 2,6-di(tert-butyl)-p-cresol, 3-iodo-2-propinyl butylcarbamate (IPBC), zinc 2-pyridinethiol 1-oxide, triazolyl 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 might include for example Zinc Pyridinethione, 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. The fungicide and / or biocide may suitably be present in an amount of from greater than 0 to 0.3wt. % of the composition and may be present in an encapsulated form where required such as described in EP2106418. As mentioned above there is also provided a method of accelerating cure of a one-part condensation curable silicone composition comprising introducing component (e) one or more co-catalyst / reaction accelerator(s) as described above into a one-part condensation curable silicone composition otherwise comprising components (a) to (d) and curing the composition. The speed of cure can be assessed by measuring the skin over time (SOT) and / or tack free time (TFT) using the methods described in the Examples below. It was found that either one or preferably both SOT and TFT showed significantly faster times than the composition without component (e) present or comparatives to component (e) present. It was surprisingly found that the amino organosilicon compounds identified as component (e) caused accelerated cure. Preferably once the components (a) to (e) and any additives or the like have been mixed together, unless the resulting composition is to be utilised immediately the composition is sealed in one or more moisture- tight containers and is stored at a temperature in a range of between 0oC and 25oC inclusive therein. In one embodiment filler (b) is first mixed into the polymer (a), optionally, if required in combination with a hydrophobic treating agent so that the filler is treated in situ during the mixing into the polymer. Once the filler is adequately mixed into the polymer (a) (and if desired has been hydrophobically treated) then the remaining components are added to make the complete composition. There is also provided a cured silicone product which is the cured product of the above composition or is the product resulting from the method described above. There is also provided a use of component (e) a co-catalyst / reaction accelerator as described above to accelerate the cure of a one-part condensation curable silicone composition otherwise comprising components (a) to (d) as described above. In one embodiment the one-part condensation curable silicone composition herein may be designed to provide a low modulus sealant composition. For the purpose of this invention, “low modulus” sealants are defined according to ISO11600, second edition 2002-10-01, section 4.3 Low modulus silicone sealant compositions are preferably “gunnable” i.e., they have a suitable extrusion capability i.e., a minimum extrusion rate of 10 ml / min as measured by ASTM C1183-04, alternatively 10 to 1000 mL / min, and alternatively 30 to 500 mL / min. The one-part condensation curable silicone composition may in such a case impart a movement capability to the post-cured sealant material. The movement capability is greater than 25 %, alternatively movement capability ranges from 25 % to 50 %, as measured by ASTM C719 - 13. A one-part condensation curable room temperature vulcanisable (RTV) silicone composition as hereinbefore described may be applied on to any suitable substrate. Suitable substrates may include, but are not limited to, glass; concrete; brick; stucco; metals, such as aluminium, copper, gold, nickel, silicon, silver, stainless steel alloys, and titanium; ceramic materials; plastics including engineered plastics such as epoxies, polycarbonates, poly(butylene terephthalate) resins, polyamide resins, polyvinyl chloride (PVC) and blends thereof, such as blends of polyamide resins with syndiotactic polystyrene commercially available from The Dow Chemical Company, of Midland, Michigan, U.S.A., acrylonitrile- butadiene-styrenes, styrene-modified poly(phenylene oxides), poly(phenylene sulfides), vinyl esters, polyphthalamides, and polyimides; cellulosic substrates such as paper, fabric, and wood; and combinations thereof. However, preferably there is provided a use of the aforementioned one-part condensation curable silicone composition as a sealant in construction applications such as in facade, insulated glass, and window and door construction applications. In the case of the one-part condensation curable silicone composition as hereinbefore described, there is provided a method for filling a space between two substrates so as to create a seal therebetween, comprising: a) providing a one-part condensation curable silicone composition as hereinbefore described and either b) applying the one-part condensation curable silicone composition to a first substrate, and bringing a second substrate in contact with the silicone composition that has been applied to the first substrate, or c) filling a space formed by the arrangement of a first substrate and a second substrate with the one-part condensation curable silicone composition and d) curing same. As previously indicated, it was unexpectedly found that when included in the formulation at low doses, e.g., 0.225 to 5.0 wt. % of the composition, component (e) substantially decreases the cure time of the sealant when using a standard amount of an organotin catalyst (component (c). Thus this can allow for the preparation of sealants with very fast cure times to match or outperform fast cure oxime sealant compositions and / or the introduction of component (e) can allow for the decrease of the component (c) organotin catalyst thereby maintaining good surface cure while obtaining improved performance (stability, adhesion, shelf life in view of the reduction in the organotin catalyst component (c). The benefit of fast cure times and / or reduction in the amounts of tin metal present in the catalyst (c) also allows for improved adhesion and adhesion durability after water immersion whilst avoiding the need to use oxime based cross-linkers for their cure speed and minimising tin content in the cured elastomers. Examples All viscosity measurements were taken at 25oC unless otherwise indicated. Unless otherwise indicated, all viscosities in the examples were measured using a Modular Compact Rheometer (MCR) 302 rheometer from Anton Paar GmbH of Graz, Austria. Viscosities in the range of 30,000-160,000 mPa.s were measured using a 40 mm diameter cone- plate and a shear rate of 1s-1; and viscosities in the range 10 to 2000 mPa.s were measured with a 75 mm diameter cone- plate and a shear rate of 1s-1. A reference composition containing no component (e) and compositions comprising or component (e) comparative additives were prepared. The compositions used for the different samples are provided in Tables 1a and 1b below. Table 1a: Compositions for Ref, Ex.1 to 3 and C.1 (wt. %) Ref Ex.1 Ex.2 Ex.3 C.1 In Table 1a: Polymer was Trimethoxysilyl terminated polydimethylsiloxane (60,000 cSt). Filler was a dimethyldichlorosilane treated fumed silica sold commercially under the AerosilTMR974 tradename by Evonik Operations in Germany. Plasticizer was a trimethylsiloxy terminated polydimethylsiloxane having a viscosity of 100 cSt, and Additive 1 was bis(3-trimethoxysilylpropyl)amine (CH3O)3Si- (CH2)3 -N(H) – (CH2)3 –Si (OCH3)3 Table 1b: The compositions of Ref, C.2, C.3 and Ex.4 to 6 Ref C.2 Ex.4 C.3 Ex.5 Ex.6 Polymer 74.00 73.75 73.75 73.75 73.75 73.75 n e a ove a e e po ymer, er an p as c zer were e same as en e above. Additive 2 (comparative) was bis(3-trimethoxysilylpropyl)-N-methylamine (CH3O)3Si- (CH2)3 -N(CH3) – (CH2)3 –Si (OCH3)3; Additive 3 was N,N'-bis[(3-trimethoxysilyl)propyl] ethylenediamine (CH3O)3Si- (CH2)3 -N(H) – (CH2)2 - N(H) - (CH2)3 –Si (OCH3)3; Additive 4 (comparative) was 1,6-bis(trimethoxysilyl)hexane (CH3O)3Si- (CH2)6–Si (OCH3)3Additive 5 was 3-aminopropyltrimethoxy silane (CH3O)3Si- (CH2)3 NH2 and Additive 6 was 3-(2-aminoethyl)aminopropyl trimethoxysilane (CH3O)3Si- (CH2)3 -N(H) – (CH2)2 – NH2. Each sample composition was assessed for its pre-cure extrusion rate and slump properties as well as for its cure characteristics by way of skin-over time (SOT), tack free time (TFT), cure in depth after 1 day. (CID). Samples were cured at room temperature for a period of 7 days at about 23oC and 50% relative humidity (RH) prior to undertaking the physical property testing unless indicated otherwise. Extrusion rate A 6-oz SemcoTMtube type CP6 HD, part # 220326 which is commercially available from PPG Industries was fitted with a plastic tapered nozzle (Model #440). The tube is then loaded into a Nordson EFDTMultra 2400 series testing unit with a one second pressure cycle at 90 psi (0.621MPa) max pressure. A test sample of uncured sealant was extruded into a waste cup on a balance to fill the tip. The material was removed and the balance tared. Holding the nozzle over the cup, the tester was activated at 90 psi (0.621MPa) max pressure after which the pressure was released. The nozzle was again removed, and the weight discharged was recorded with the value being converted to g / min. Slump was measured using an aluminum Frazier Boeing slump jig (made of aluminum), commercially available from Frazier Precision Instrument Company Inc. with the plunger fully depressed. Sealant was added to the cavity of the slump jig, whilst avoiding incorporation of bubbles; enough is added to overflow above the top frame of the jig. Using a wide spatula, excess material was removed (keeping the jig flat), using a lateral motion, leaving material filling only the cavity of the jig. Next, the jig was positioned vertically; subsequently the plunger of the cavity is popped out so that the sealant is protruded forward. After 10 minutes, the vertical displacement was recorded, in 0.05-inch (1.27mm) increments. Skin over time (SOT) A draw down was made using a 100-mil (0.254cm) drawdown bar on standard polyethylene film. Care was taken to ensure a smooth surface, free of imperfections such as air bubbles or drag marks. Time was noted once a slab of the sealant had been prepared. The samples were cured at 70Fahrenheit (about 21oC) and 40% relative humidity. The surface was touched every minute or so with a nitrile gloved fingertip and slowly lifted away. Skin over time (SOT) is reached when the sample no longer adheres to the nitrile gloved fingertip skin. Tack free time (TFT) was determined by preparing a sample piece in the same manner as above for SOT except the surface of the sealant was touched with a 0.25 inch(0.625cm) wide strip of polyethylene film and the TFT was reached when the strip of polyethylene film no longer adhered to the sample. Again, the samples were cured at 70 Fahrenheit (about 21oC) and 40% relative humidity. Cure in Depth (CID): Sealant was extruded into a polyethylene SemcoTMplunger (PPG Semco Precision High Density Wiper Plunger, SKU 220260) in excess. A spatula was then used to remove excess sealant, making a flat surface across the top of the plunger. After a 1-day cure period a micro spatula was run along the edge of the sample, between the plunger and cured sealant, breaking the cured material from the plunger. The plug was removed from the plunger and placed wet side up on a piece of polypropylene plastic and the uncured sealant scraped off the plug. The plug was allowed to dry and then the thickness was measured using a micrometer. The results in respect to extrusion rate, slump, SOT, TFT and CID for the reference sample, each example and each comparative example and the results are provided in Tables 2a and 2b below. Table 2a: Extrusion rate, slump, SOT, TFT and CID results for the reference sample, Ex.1 to 3 and comparative C.1. Ref Ex.1 Ex.2 Ex.3 C.1 Extrusion rate (g / min) 108 73 64 93 228 e reference sample, Ex.4 to 6 and C.2 to C.3 Ref C.2 Ex.4 C.3 Ex.5 Ex.6 Extrusion rate (g / min) 108 62 64 95 76 57 . y g y p, C.2 had a slightly lower extrusion rate that most of the examples, but a significantly higher slump and C.3 had a higher extrusion rate than most examples but again a significantly higher slump. Hence, overall, all the comparatives had poor slump results other than C.1 but the latter had a very high extrusion rate. All the Examples had good SOT results and most had excellent TFT results too. Each of the examples were also tested for their physical properties in respect of durometer (Shore A) tensile strength, elongation at break, and modulus at 100% extension. In each case the samples used had been left to cure for 7 days at room temperature. Durometer (Shore A) Shore A durometer was measured on a digital ZwickRoell 3130 hardness tester (BH04.7206.200) with a 12.5 N load weight for Shore A digital durometer head (BH04.3130.000; ASTM C661). A dwell time of 1 second was used to conform to ASTM D2240. Samples were stacked at least 0.25 inches (0.635cm) thick. Tensile Properties Tensile properties were evaluated according to ASTM D 412. However, tensile dogbone specimens were cut out of the slab using a smaller than called for die to cut the dogbones (DIN 53504 S2 Die) to allow room on the tensometer’s (MTS Systems Corporation Alliance RT / 5 frame for the dogbone to pull to break. They were pulled at 20 inches a minute (50.8cm per min) using a 22.5 lbf (100 N) load cell. The results are provided in Tables 3a and 3b below. Table 3a: Durometer and Tensile properties of Ref., Ex.1 – 3 and C.1 Ref Ex.1 Ex.2 Ex.3 C.1 Durometer (Shore A) 13 13 20 31 49 Ref C.2 Ex.4 C.3 Ex.5 Ex.6 Durometer (Shore A) 13 13 14 12 17 19 al was very brittle. This is recognized from the poor tensile, elongation and modulus results.

Claims

WHAT IS CLAIMED IS:

1. A one-part condensation curable silicone composition comprising: (a) an organopolysiloxane polymer having an average of at least two silicon-bonded hydrolysable groups per molecule; and a viscosity of from 750 to 150,000mPa.s at 25oC, (b) One or more reinforcing fillers, one or more non-reinforcing fillers or a mixture thereof; (c) an organotin condensation catalyst in an amount of from 0.001 to 1.0 wt. % of the composition; (d) one or more organosilane cross-linkers having at least two alkoxy groups, alternatively at least three alkoxy groups, per molecule; and (e) a co-catalyst / reaction accelerator selected from one or more amino organosilicon compounds of the following structures: (R10)3Si-X2-N(H) – X2– Si(R10)3; (R10)3Si-X2-N(H) - (CH2)2– N(H) – X2– Si(R10)3; NH2 – X2– Si(R10)3; or NH2 (CH2)2 -N(H) – X2– Si(R10)3 where each R10is independently a methoxy or ethoxy group and each X2is independently a linear alkyl group having from 1 to 6 carbons; which is present in the composition in an amount of from 0.225 to 5.0 wt. % of the composition.

2. A one-part room temperature vulcanisable (RTV) silicone composition in accordance with claim 1 wherein component (a) has the structure: X3-nRnSi-Z- (R1ySiO(4-y) / 2)z –SiR12 -Z-Si-RnX3-n (1) in which each X is independently an alkoxy group, each R is an alkyl, alkenyl or aryl group, each R1is an alkoxy group, an alkyl group, an alkenyl group or an aryl group and Z is oxygen or a divalent organic group containing from 2 to 10 carbons; each n is independently 0, 1, 2 or 3, y is 0, 1 or 2, and z is an integer consistent with said organopolysiloxane polymer having a viscosity of from 750 to 150,000mPa.s at 25oC.

3. A one-part room temperature vulcanisable (RTV) silicone composition in accordance with any preceding claim wherein component (e) is selected from one or more of bis (3- trimethoxysilylpropyll)amine, bis (3-triethoxysilylpropyll)amine. N,N’-bis[(3-trimethoxysilyl)alkyl]ethylenediamine, and N,N’-bis[(3- triethoxysilyl)alkyl]ethylenediamine, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane.3- (2-aminoethyl)aminopropyltrimethoxysilane and 3-(2-aminoethyl)aminopropyltrimethoxysilane.

4. A one-part room temperature vulcanisable (RTV) silicone composition in accordance with any preceding claim wherein the organotin condensation catalyst (c) may be selected from one or more of tin triflates, dimethyltin di-2-ethylhexanoate, dimethyltin dilaurate, di-n-butyltin diacetate (DBTDA), di-n- butyltin di-2-ethylhexanoate, dimethyltin dineodecanoate (DMTDN), dioctyltin dineodecanoate(DOTDN), di-n-butyltin dicaprylate, di-n-butyltin di-2,2-dimethyl octanoate, di-n-butyltin octanoate, di- n- butyltin dilaurate (DBTDL), di-n-butyltin distearate, di-n-butyltin dimaleate, dipropyl tin bis(acetylacetonate), dibutyl tin bis(acetylacetonate), dipentyl tin bis(acetylacetonate), dihexyl tin bis(acetylacetonate), dioctyl tin bis(acetylacetonate), didecyl tin bis(acetylacetonate), didodecyl tin bis(acetylacetonate), di-n-butyltin dioleate, di-n-octyltin di-2-ethylhexanoate, di-n-octyltin di-2,2- dimethyl octanoate, di-n-octyltin dimaleate, Di-n-octyl tin dilaurate (DOTDL), di-n-butyl tin oxide, carbomethoxyphenyl tin trisuberate, tin butyrate, butyltintri-2-ethylhexoate, tin naphthenate, isobutyltintriceroate, tin octoate, triethyltin tartrate and di-n-octyl tin oxide.

5. A one-part room temperature vulcanisable (RTV) silicone composition in accordance with any preceding claim wherein the organotin condensation catalyst of component (c) is present in an amount of from 0.05 to 0.5 wt.% of the composition.

6. A one-part room temperature vulcanisable (RTV) silicone composition in accordance with any preceding claim which additionally comprises one or more additives selected from rheological modifiers, water / moisture scavengers, plasticizers and / or extenders, pigments & colorants, s, antioxidants, UV and / or light stabilizers and biocides.

7. A method of accelerating cure of a one-part condensation curable silicone composition comprising introducing one or more co-catalyst / reaction accelerator(s) selected from one or more amino organosilicon compounds of the following structures: (R10)3Si-X2-N(H) – X2– Si(R10)3; (R10)3Si-X2-N(H) - (CH2)2– N(H) – X2– Si(R10)3; NH2– X2– Si(R10)3; or NH2 (CH2)2 -N(H) – X2– Si(R10)3 where each R10is independently a methoxy or ethoxy group and each X2is independently a linear alkyl group having from 1 to 6 carbons; which is present in the composition in an amount of from 0.225 to 5.0 wt. % of the composition; into a one-part condensation curable silicone composition otherwise comprising (a) an organopolysiloxane polymer having an average of at least two silicon-bonded hydrolysable groups per molecule; and a viscosity of from 750 to 150,000mPa.s at 25oC, (b) One or more reinforcing fillers, one or more non-reinforcing fillers or a mixture thereof; (c) an organotin condensation catalyst in an amount of from 0.001 to 1.0 wt. % of the composition; and (d) one or more silane cross-linkers having at least two alkoxy groups, alternatively at least three alkoxy groups, per molecule; and curing the composition.

8. A method of accelerating cure of a one-part condensation curable silicone composition in accordance with claim 7 wherein component (e) is selected from one or more of bis (3- trimethoxysilylpropyll)amine, bis (3-triethoxysilylpropyll)amine. N,N’-bis[(3-trimethoxysilyl)alkyl]ethylenediamine, and N,N’-bis[(3- triethoxysilyl)alkyl]ethylenediamine, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane.3- (2-aminoethyl)aminopropyltrimethoxysilane and 3-(2-aminoethyl)aminopropyltrimethoxysilane.

9. A method of accelerating cure of a one-part condensation curable silicone composition in accordance with claim 7 or 8 wherein the organotin condensation catalyst (c) may be selected from one or more of tin triflates, dimethyltin di-2-ethylhexanoate, dimethyltin dilaurate, di-n-butyltin diacetate (DBTDA), di-n-butyltin di-2-ethylhexanoate, dimethyltin dineodecanoate (DMTDN), dioctyltin dineodecanoate (DOTDN), di-n-butyltin dicaprylate, di-n-butyltin di-2,2-dimethyl octanoate, di-n- butyltin octanoate, di-n- butyltin dilaurate (DBTDL), di-n-butyltin distearate, di-n-butyltin dimaleate, di- n-butyltin dioleate, di-n-octyltin di-2-ethylhexanoate, di-n-octyltin di-2,2-dimethyl octanoate, di-n- octyltin dimaleate, Di-n-octyl tin dilaurate (DOTDL), di-n-butyl tin oxide, carbomethoxyphenyl tin trisuberate, tin butyrate, butyltintri-2-ethylhexoate, tin naphthenate, isobutyltintriceroate, tin octoate, triethyltin tartrate and di-n-octyl tin oxide.

10. A method of accelerating cure of a one-part condensation curable silicone composition in accordance with claim 7, 8 or 9 wherein the organotin condensation catalyst of component (c) is present in an amount of from 0.05 to 0.5 wt.% of the composition.

11. A cured silicone product which is the cured product of the in accordance with any one of claims 1 to 6 or is the product resulting from the method in accordance with claims 7, 8, 9 or 10.

12. Use of one or more an amino organosilicon compounds of the following structures: (R10)3Si-X2-N(H) – X2– Si(R10)3; (R10)3Si-X2-N(H) - (CH2)2 – N(H) – X2– Si(R10)3; NH2 – X2– Si(R10)3; or NH2(CH2)2-N(H) – X2– Si(R10)3where each R10is independently a methoxy or ethoxy group and each X2is independently a linear alkyl group having from 1 to 6 carbons; which is present in the composition in an amount of from 0.225 to 5.0 wt. % of the composition; as a co-catalyst / reaction accelerator in a one-part condensation curable silicone composition wherein said one-part condensation curable silicone composition otherwise comprises: (a) an organopolysiloxane polymer having an average of at least two silicon-bonded hydrolysable groups per molecule; and a viscosity of from 750 to 150,000mPa.s at 25oC, (b) One or more reinforcing fillers, one or more non-reinforcing fillers or a mixture thereof; (c) an organotin condensation catalyst in an amount of from 0.001 to 1.0 wt. % of the composition; and(d) one or more organosilane cross-linkers having at least two alkoxy groups, alternatively at least three alkoxy groups, per molecule.

13. Use of one or more amino organosilicon compounds in accordance with claim 12 wherein component (e) is selected from one or more of bis (3-trimethoxysilylpropyll)amine, bis (3- triethoxysilylpropyll)amine. N,N’-bis[(3-trimethoxysilyl)alkyl]ethylenediamine, and N,N’-bis[(3- triethoxysilyl)alkyl]ethylenediamine, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane.3- (2-aminoethyl)aminopropyltrimethoxysilane and 3-(2-aminoethyl)aminopropyltrimethoxysilane.

14. Use of one or more amino organosilicon compounds in accordance with claim 12 or 13 wherein the organotin condensation catalyst (c) may be selected from one or more of tin triflates, dimethyltin di- 2-ethylhexanoate, dimethyltin dilaurate, di-n-butyltin diacetate (DBTDA), di-n-butyltin di-2- ethylhexanoate, dimethyltin dineodecanoate (DMTDN), dioctyltin dineodecanoate (DOTDN), di-n- butyltin dicaprylate, di-n-butyltin di-2,2-dimethyl octanoate, di-n-butyltin octanoate, di-n- butyltin dilaurate (DBTDL), di-n-butyltin distearate, di-n-butyltin dimaleate, di-n-butyltin dioleate, di-n-octyltin di-2-ethylhexanoate, di-n-octyltin di-2,2-dimethyl octanoate, di-n-octyltin dimaleate, dipropyl tin bis(acetylacetonate), dibutyl tin bis(acetylacetonate), dipentyl tin bis(acetylacetonate), dihexyl tin bis(acetylacetonate), dioctyl tin bis(acetylacetonate), didecyl tin bis(acetylacetonate), didodecyl tin bis(acetylacetonate),Di-n-octyl tin dilaurate (DOTDL), di-n-butyl tin oxide, carbomethoxyphenyl tin trisuberate, tin butyrate, butyltintri-2-ethylhexoate, tin naphthenate, isobutyltintriceroate, tin octoate, triethyltin tartrate and di-n-octyl tin oxide.

15. Use of one or more amino organosilicon compounds in accordance with claim 12, 13 or 14 wherein the organotin condensation catalyst of component (c) is present in an amount of from 0.05 to 0.5 wt.% of the composition.

16. Use of a one-part condensation curable silicone composition in accordance with any one of claims 1 to 6 as a sealant in façade applications, insulated glass applications or window and door construction applications.

17. A method for filling a space between two substrates to create a seal therebetween, comprising: a) providing a one-part condensation curable silicone composition in accordance with any one of claims 1 to 6 and either b) applying the one-part condensation curable silicone composition to a first substrate, and bringing a second substrate in contact with the silicone composition that has been applied to the first substrate, or c) filling a space formed by the arrangement of a first substrate and a second substrate with the one-part condensation curable silicone composition and d) curing same.

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