[0001] This concerns a two-part moisture cure organosiloxane composition comprising a base component and a catalyst package wherein the catalyst package is provided with a diamine type adhesion promoter to at least partially replace one or more monoamine adhesion promotors to give improved speed of adhesion to substrates which are known to be difficult to adhere silicone sealants to, e.g. metallised glass coatings.

[0002] Condensation curable organosiloxane compositions, which cure to elastomeric solids, are well known. Typically, such compositions are obtained by mixing a polydiorganosiloxane having reactive terminal groups, e.g. hydroxy groups or hydrolysable groups, with e.g. a silane cross- linking agent which is reactive with the polydiorganosiloxane, for example an acetoxy silane, an oximosilane, an aminosilane or an alkoxysilane in the presence of a suitable catalyst. The resulting compositions are curable upon exposure to atmospheric moisture at room temperature and may be used as structural sealants/adhesives.

[0003] In use as sealants, it is important that a composition is capable of curing in comparatively thick layers to provide an elastomeric body. It is frequently desirable that the organopolysiloxane composition cures quickly enough to provide a sound seal within several hours but not so quickly, that the surface cannot be tooled to desired configuration shortly after application. Dependent on several factors, for example, the means of cure (e.g. cross-linker and catalyst), the intended thickness of sealant layer to be applied and the substrate(s) on to which the sealant is to be applied, such compositions may be provided to the user in a one-part curable product, which can be applied onto a substrate directly or alternatively in a multi-part, typically two-part, combination requiring the multiple parts to be mixed together immediately before use.

[0004] The properties of individual parts of said multi-part compositions are generally not affected by atmospheric moisture, but once mixed together the resulting mixture possess excellent deep curability and enables substantially uniform curing throughout the entire body of the sealing material, i.e., from the surface to the inner part and therefore tends to be used when fast cure and thick layers (e.g. >15mm) are to be applied. Typically, such two-component compositions comprise a first (base) component that typically contains silanol-terminated diorganopolysiloxane and a reinforcing filler, e.g. calcium carbonate and a second component (catalyst or cure package) containing an alkyl-terminated diorganopolysiloxane, tin based catalyst, cross-linker and adhesion promoter. The standard adhesion promoters used are monoaminosilanes such as bis(3- triethoxysilylpropyl)amine or gamma-aminopropyltriethoxy silane.

[0005] It is generally acknowledged that the speed of adhesion of this type of two-component composition, subsequent to mixing the two-components together, can be easily accelerated by increasing either or both of the tin catalyst level and the (monoaminosilane) adhesion promoter level. However, with the increase of adhesion promoter, especially in the case of said monoamino silanes, the alkyl-terminated diorganopolysiloxane in the catalyst package undergoes random chain scission, which causes viscosity to decrease and consequently destabilises the mixture. It has now been identified that rather than providing additional monoaminosilane to improve speed of adhesion, but risk the destabilizing effect, by at least partially replacing one or more monoaminosilanes with an equivalent weight % (wt. %) of diaminosilane based on the total weight % (wt. %) of the composition provides a surprising increase in speed of adhesion and avoids the need to introduce additional monoaminosilane adhesion promoter and thereby avoids the destabilizing effects as a consequence of adding said additional adhesion promoter.

[0006] There is provided herein a two-component moisture curing silicone composition having a base component and a catalyst package component in which, the catalyst package component comprises:

(i) a polydialkylsiloxane having the general formula:

R ³ 3-Si-0-((R ² ) ₂ Si0)a-Si-R ³ ₃ (2) where R ² is an alkyl or phenyl group, each R ³ group may be the same or different and are selected from R ² alkyl, phenyl, alkenyl or alkynyl groups having a viscosity of from about 5 to about 100,000 mPa.s at 25°C, i.e. a is an integer which provides this viscosity range;

(ii) an adhesion promoter selected from (iia) and optionally (iib) in an amount of 5 to 50% by weight of the catalyst package composition wherein (iia) is a diaminosilane adhesion promoter of the structure in accordance with the formula:

R ⁴ _t (RO) _3-t Si-Z ¹ -N(H)- (CH ₂ ) _m - NH ₂ in which R ⁴ is an alkyl group containing from 1 to 10 carbon atoms; each R’ may be the same or different and is H or R ⁴ , Z ¹ is a linear or branched alkylene group having from 2 to 10 carbon atoms, m is from 2 to 10 and t is 0 or 1 ; and (iib) one or more monoaminosilane adhesion promoters;

(iii) a cross-linker; and

(iv) a tin based catalyst.

[0007] Any suitable base component may be utilized. For example, the base component may comprise:

(a) a organopolysiloxane polymer having at least two terminal hydroxyl or hydrolysable groups having a viscosity of from 1500 to 150,000 mPa.s at 25°C;

(b) one or more reinforcing fillers; and optionally

(c) one or more non-reinforcing fillers.

[0008] Alternatively, there is provided herein a two-component moisture curing silicone composition having a base component and a catalyst package component in which, the base component comprises: (a) a organopolysiloxane polymer having at least two terminal hydroxyl or hydrolysable groups having a viscosity of from 1500 to 150000 mPa.s at 25°C;

(b) one or more reinforcing fillers; and optionally

(c) one or more non-reinforcing fillers and the catalyst package comprising:

(i) a polydialkylsiloxane which is unreactive with polymer (a) of the base component, having the general formula :

R ³ ₃ -Si-0-((R ² ) ₂ Si0) _a -Si-R ³ ₃ (2) where R ² is an alkyl or phenyl group, each R ³ group may be the same or different and are selected from alkyl, phenyl, alkenyl or alkynyl groups having a viscosity of from about 5 to about 100,000 mPa.s at 25°C, i.e. a is an integer which provides this viscosity range;

(ii) an adhesion promoter selected from (iia) and optionally (iib) in an amount of 5 to 50% by weight of the catalyst package composition wherein

(iia) is a diaminosilane adhesion promoter of the structure in accordance with the formula:

R ⁴ _{t (} RO) ₃ -,Si-Z'-N(H)- (CH ₂ ) _m - NH ₂ in which R ⁴ is an alkyl group containing from 1 to 10 carbon atoms; each R’ may be the same or different and is H or R ⁴ , Z ¹ is a linear or branched alkylene group having from 2 to 10 carbon atoms, m is from 2 to 10 and t is 0 or 1 ; and (iib) one or more monoaminosilane adhesion promoters

(iii) a cross-linker; and

(iv) a tin based catalyst.

[0009] Unless otherwise indicated all viscosity measurements were determined in accordance with Corporate test method CTM 0050, which is publicly available, and which is based on ASTM D 1084-16 method B, using a Brookfield ^® HBDV-III Ultra Rheometer equipped with a cone-and-plate geometry using spindle CP-52. The composition is typically curable and/or cured at room temperature which is often referred to as room temperature vulcanisable (RTV). The terms “% by weight”, “weight %” and “wt. %” are used interchangeably.

[0010] The base component may comprise (a) an organopolysiloxane polymer having at least two terminal hydroxyl or hydrolysable groups having a viscosity of from 1500 to 150000 mPa.s at 25°C. The organopolysiloxane polymer (a) having at least two hydroxyl or hydrolysable groups per molecule has the formula

X _3-n R _n Si-(Z) -(0) _q - (R' _y SiC h -(SiR' ₂ - Z) _d -Si-R„X ₃ -„ (D in which each X is independently a hydroxyl group or a hydrolysable group, each R is an alkyl, alkenyl or aryl group, each R ¹ is an X group, alkyl group, alkenyl group or aryl group and Z is a divalent organic group; d is 0 or 1, q is 0 or 1 and d+ q = 1; n is 0, 1, 2 or 3, y is 0, 1 or 2, and z is an integer such that said organopolysiloxane polymer (a) has a viscosity of from 1500 to 150000 mPa.s at 25°C, alternatively 10,000 to 75,000 mPa.s at 25 °C, alternatively from 10,000 to 60,000mPa.s at 25°C.

[0011] Each X group of organopolysiloxane polymer (a) may be the same or different and can be a hydroxyl group or a condensable or hydrolyzable group. The term "hydrolyzable group" means any group attached to the silicon which is hydrolyzed by water at room temperature. The hydrolyzable group X includes groups of the formula -OT, where T is an alkyl group such as methyl, ethyl, isopropyl, octadecyl, an alkenyl group such as allyl, hexenyl, cyclic groups such as cyclohexyl, phenyl, benzyl, beta-phenylethyl; hydrocarbon ether groups, such as 2-methoxyethyl, 2- ethoxyisopropyl, 2-butoxyisobutyl, p-methoxyphenyl or -(OREOEO^ϋ-E _.

[0012] The most preferred X groups are hydroxyl groups or alkoxy groups. Illustrative alkoxy groups are methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, pentoxy, hexoxy octadecyloxy and 2-ethylhexoxy; dialkoxy groups, such as methoxymethoxy or ethoxymethoxy and alkoxyaryloxy, such as ethoxyphenoxy. The most preferred alkoxy groups are methoxy or ethoxy. [0013] Each R is individually selected from alkyl groups, alternatively alkyl groups having from 1 to 10 carbon atoms, alternatively from 1 to 6 carbon atoms, alternatively 1 to 4 carbon atoms, alternatively methyl or ethyl groups; alkenyl groups alternatively alkenyl groups having from 2 to 10 carbon atoms, alternatively from 2 to 6 carbon atoms such as vinyl, allyl and hexenyl groups; aromatic groups, alternatively aromatic groups having from 6 to 20 carbon atoms, substituted aliphatic organic groups such as 3,3,3-trifluoropropyl groups aminoalkyl groups, polyaminoalkyl groups, and/or epoxyalkyl groups.

[0014] Each R ¹ is individually selected from the group consisting of X or R with the proviso that cumulatively at least 2 X groups and/or R ¹ groups per molecule are hydroxyl or hydrolysable groups. It is possible that some R ¹ groups may be siloxane branches off the polymer backbone which branches may have terminal groups as hereinbefore described. Most preferred R ¹ is methyl.

[0015] Each Z is independently selected from an alkylene group having from 1 to 10 carbon atoms. In one alternative each Z is independently selected from an alkylene group having from 2 to 6 carbon atoms; in a further alternative each Z is independently selected from an alkylene group having from 2 to 4 carbon atoms. Each alkylene group may for example be individually selected from an ethylene, propylene, butylene, pentylene and or hexylene group.

[0016] In the present instance, preferably d is 0, q is 1, n is 1 or 2, alternatively n is 2 and each X is a hydroxyl group. In such a case organopolysiloxane polymer (a) has the following structure: HO(R ₂ )Si-0 (R ¹ _y SiO( _4-y)/2 ) _z -Si-(R ₂ ) OH with R, R ¹ , Z, y and z being as described above. [0017] Organopolysiloxane polymer (a) has a viscosity of from 1500 to 150000 mPa.s at 25 °C, alternatively 10,000 to 75,000 mPa.s at 25°C, alternatively from 10,000 to 60,000mPa.s at 25°C.

, z is therefore an integer enabling such a viscosity, alternatively z is an integer from 300 to 5000. Whilst y is 0, 1 or 2, substantially y= 2, e.g. at least 90% alternatively 95% of R ¹ _y SiO ₍ 4- _y )/2 groups are characterized with y = 2,

[0018] 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, the term "siloxane polymer mixture" in respect to organopolysiloxane polymer (a) is meant to include any individual organopolysiloxane polymer (a) or mixtures of organopolysiloxane polymer (a). [0019] 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%. This technique is standard and yields Mw, Mn and polydispersity index (PI). The degree of polymerisation (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.

[0020] Organopolysiloxane polymer (a) is present in the composition in an amount of from 10 to 60% by weight, alternatively 10 to 55%, alternatively 20 to 55% by weight of the composition. Organopolysiloxane polymer (a) is going to be present in an amount of from 20 to 80% by weight of the base composition, alternatively from 35 to 65 % by weight of the base composition.

[0021] The base component reinforcing filler (b) may contain one or more finely divided, reinforcing fillers such as precipitated calcium carbonate, high surface area fumed silica and/or high surface area precipitated silica including, for example, rice hull ash. Typically, the surface area of the reinforcing filler (b) is at least 50 m ² /g. In the case of high surface area fumed silica and or high surface area precipitated silica, these may have surface areas of, for example, from 100 to 400 m ² /g measured in accordance with the BET method (ISO 9277: 2010);, alternatively of from 100 to 300 m ² /g in accordance with the BET method (ISO 9277: 2010). Typically, the reinforcing fillers are present in the base composition in an amount of from 20 to 70% by weight, alternatively from 35 to 65% by weight.

[0022] The optional non-reinforcing filler (c) of the base component may comprise non-reinforcing fillers such as ground calcium carbonate, crushed quartz, diatomaceous earths, barium sulphate, iron oxide, titanium dioxide and carbon black, talc, wollastonite. Other fillers which might be used alone or in addition to the above include aluminite, calcium sulphate (anhydrite), gypsum, 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.

[0023] Aluminium oxide, 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 Mg ₂ Si0 ₄ . The garnet group comprises ground silicate minerals, such as but not limited to, pyrope; MgsAhS On; grossular; and Ca ₂ Al ₂ Si ₃ 0i ₂ . Aluminosilicates comprise ground silicate minerals, such as but not limited to, sillimanite; AI ₂ S1O ₅ ; mullite; 3AI ₂ O ₃ .2S1O ₂ ; kyanite; and AI ₂ S1O ₅

The ring silicates group comprises silicate minerals, such as but not limited to, cordierite and Al ₃ (Mg,Fe) ₂ [Si ₄ A10i ₈ ]. The chain silicates group comprises ground silicate minerals, such as but not limited to, wollastonite and CafSiCb].

[0024] The sheet silicates group comprises silicate minerals, such as but not limited to, mica; K ₂ AIi ₄ [Si ₆ Al ₂ 0 ₂ o](OH) ₄ ; pyrophyllite; AL^SisChoKOHU; talc; Mg ₆ [Sis0 ₂ o](OH) ₄ ; serpentine for example, asbestos; Kaolinite; AL^S OioKOHis; and vermiculite. The optional non-reinforcing filler, when present, is present in an amount up to 20% by weight of the base.

[0025] In addition, a surface treatment of the reinforcing filler (b) of the base component and optional non-reinforcing filler (c) of the base component may be performed, for example with a fatty 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) (b) and optionally (c) hydrophobic and therefore easier to handle and obtain a homogeneous mixture with the other sealant components The surface treatment of the fillers (b) and optionally (c) makes them easily wetted by organopolysiloxane polymer (a) of the base component. These surface modified fillers do not clump and can be homogeneously incorporated into the silicone polymer (a) of the base component. This results in improved room temperature mechanical properties of the uncured compositions. The fillers (b) and optionally (c) may be pre-treated or may be treated in situ when being mixed with polymer (a).

Catalyst package

[0026] As hereinbefore described the catalyst package of the two-component composition comprises polydialkylsiloxane (i) which is unreactive with any reactive polymer in the base component (i.e. polymer (a) discussed above). Polydialkylsiloxane (i) may have the general formula R ³ ₃ -Si-0-((R ² ) ₂ Si0)d-Si-R ³ ₃ (2) where each R ² may be the same or different and is an alkyl or phenyl group, alternatively a Cwo alkyl group, alternatively a Ci- ₆ alkyl group, alternatively a methyl or ethyl group; each R ³ group may be the same or different and is selected from R ² above or an alkenyl or alkynyl group.

Typically, polydialkylsiloxane (i) has a viscosity of from about 5 to about 100,000 mPa.s at 25°C, with d being an integer resulting in a polydialkylsiloxane within the specified viscosity range. Typically, these are polydimethylsiloxanes which are unreactive with organopolysiloxane polymer (a) of the base composition. For example, a polydimethylsiloxane in which each R ² is a methyl group and each R ³ groups are, for example, methyl, vinyl or phenyl or combinations of these groups. Typically, polydialkylsiloxane (i) is linear but it may contain a degree of branching. Polydialkylsiloxane (i), which is unreactive with organopolysiloxane polymer (a), is typically present in the catalyst package as a carrier and is present in an amount of from 30 to 80 weight %, of the catalyst package, alternatively 40 to 65 weight %.

[0027] The catalyst package of the two-component composition also contains an X total weight % of adhesion promoter selected from (iia) and optionally (iib) wherein

(iia) a diaminosilane adhesion promoter of the structure in accordance with the formula:

R ⁴ _{t (} ROb-.Si-Z'-NiH)- (CH ₂ ) _m - NH ₂ in which R ⁴ is an alkyl group containing from 1 to 10 carbon atoms; each R’ may be the same or different and is H or R ⁴ , Z ¹ is a linear or branched alkylene group having from 2 to 10 carbon atoms, m is from 2 to 10 and t is 0 or 1 ; and (iib) one or more monoaminosilane adhesion promoters.

The diaminosilane adhesion promoter (iia) has the formula: - R ⁴ _{t (} ROh-Si-Z'-Ndl)- (CH ₂ ) _m - NH ₂ in which R ⁴ is an alkyl group containing from 1 to 10 carbon atoms; each R’ may be the same or different and is H or R ⁴ , Z ¹ is a linear or branched alkylene group having from 2 to 10 carbon atoms, m is from 2 to 10 and t is 0 or 1 ;

[0028] R ⁴ is an alkyl group containing from 1 to 10 carbon atoms, alternatively R ⁴ is an alkyl group containing from 1 to 6 carbon atoms, alternatively, R ⁴ is a methyl or ethyl group. Each R’ may be the same or different and is each R’ may be the same or different and is H or R ⁴ , alternatively each R’ is R ⁴ . In one alternative the two R’ groups are the same. When the two R’ groups are the same, it is preferred that they are methyl or ethyl groups. Z ¹ is a linear or branched alkylene group having from 2 to 10 carbons, alternatively from 2 to 6 carbons, for example Z ¹ may be a propylene group, a butylene group or an isobutylene group. There may be from 2 to 10 m groups, in one alterative m may be from 2 to 6, in another alternative m may be from 2 to 5, in a still further alternative m may be 2 or 3, alternatively m is 2.

Specific examples of adhesion promoter (iia) when t =1 include but are not limited to 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-aminopropylmethyldiethoxysilane, N-(2- aminoethyl)-2-aminoethylmethyldiethoxysilane, 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-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- aminopropylmethylmethoxyethoxysilane, N-(2-aminopropyl)-2- aminoethylmethylmethoxyethoxysilane, N-(2-aminopropyl)-3- aminoisobutylethylmethoxyethoxysilane and N-(2-aminopropyl)-2- aminoethylmethylmethoxyethoxysilane.

Specific examples of adhesion promoter (iia) when t =0 include but are not limited to

N-(2-aminoethyl)-3-aminoisobutyltrimethoxysilane,

N-(2-aminoethyl)-3-aminopropyltrimethoxysilane,

N-(2-aminoethyl)-3-aminopropyltriethoxysilane,

N-(2-aminoethyl)-2-aminoethyltriethoxysilane,

N-(2-aminoethyl)-3-aminoisobutyltriethoxysilane,

N-(2-aminopropyl)-3-aminoisobutyltrimethoxysilane,

N-(2-aminoethyl)-3-aminopropyldimethoxyethoxysilane,

N-(2-aminoethyl)-3-aminopropylmethoxydiethoxysilane,

N-(2-aminoethyl)-2-aminoethyldimethoxyethoxysilane,

N-(2-aminoethyl)-2-aminoethylmethoxydiethoxysilane,

N-(2-aminoethyl)-3-aminoisobutyldimethoxyethoxysilane, and

N-(2-aminoethyl)-3-aminoisobutylmethoxydiethoxysilane.

[0029] The catalyst package of the two-component composition also optionally contains one or more monoamino silane adhesion promoters (iib). The monoamino silane adhesion promoters (iib) may be any silane adhesion promoter containing one single primary, secondary or tertiary amino group per molecule i.e. a maximum and minimum of one primary, secondary or tertiary amino group per molecule and for the avoidance of doubt specifically excludes silane adhesion promoters containing more than one primary, secondary or tertiary amino group per molecule.

[0030] The monoamino silane adhesion promoter (iib) may comprise dipodal silanes. [0031] Examples of dipodal Silane versions of monoamino silane adhesion promoter (iib) include: bis (trialkoxysilylalkyl)amines, bis (dialkoxyalkylsilylalkyl)amine,

• bis (trialkoxysilylalkyl) N-alkylamine, bis (dialkoxyalkylsilylalkyl) N-alkylamine and

• bis (trialkoxysilylalkyl)urea and bis (dialkoxyalkylsilylalkyl) urea.

[0032] Specific suitable examples of monoamino silane adhesion promoter (iib) when a dipodal Silane include example bis (3-trimethoxysilylpropyl)amine, bis (3-triethoxysilylpropyl)amine, bis (4-trimethoxysilylbutyl)amine, bis (4-triethoxysilylbutyl)amine, bis (3-trimethoxysilylpropyl)N-methylamine, bis (3-triethoxysilylpropyl) N-methylamine, bis (4-trimethoxysilylbutyl) N-methylamine, bis (4-triethoxysilylbutyl) N-methylamine, bis (3-trimethoxysilylpropyl)urea, bis (3-triethoxysilylpropyl)urea, bis (4-trimethoxysilylbutyl)urea, bis (4- triethoxysilylbutyl )urea, bis (3-dimethoxymethylsilylpropyl)amine, bis (3-diethoxymethyl silylpropyl)amine, bis (4-dimethoxymethylsilylbutyl)amine, bis (4- diethoxymethyl silylbutyl)amine, bis (3-dimethoxymethylsilylpropyl) N-methylamine, bis (3-diethoxymethyl silylpropyl) N-methylamine, bis (4-dimethoxymethylsilylbutyl) N-methylamine, bis (4- diethoxymethyl silylbutyl) N-methylamine, bis (3-dimethoxymethylsilylpropyl)urea, bis (3- diethoxymethyl silylpropyl)urea, bis (4-dimethoxymethylsilylbutyl)urea, bis (4- diethoxymethyl silylbutyl)urea, bis (3-dimethoxyethylsilylpropyl)amine, bis (3-diethoxyethyl silylpropyl)amine, bis (4-dimethoxyethylsilylbutyl)amine, bis (4- diethoxyethyl silylbutyl)amine, bis (3-dimethoxyethylsilylpropyl) N-methylamine, bis (3-diethoxyethyl silylpropyl) N-methylamine, bis (4-dimethoxyethylsilylbutyl) N-methylamine, bis (4- diethoxyethyl silylbutyl) N-methylamine, bis (3-dimethoxyethylsilylpropyl)urea bis (3- diethoxyethyl silylpropyl)urea, bis (4-dimethoxyethylsilylbutyl)urea and/or bis (4- diethoxyethyl silylbutyl)urea.

[0033] In a still further alternative the dipodal silanes of component (iib)may be selected from a bis (trialkoxysilylalkyl) amine such as bis (3-tripropyloxysilypropyl)amine, bis (3- methyldiethoxysilypropyl)amine, bis (3-methyldimethoxysilypropyl)amine, as well as bis (3-triethoxysilylpropyl)amine or bis (3-trimethoxysilylpropyl)amine

[0034] The dipodal silane (iib) is compatible with the polydialkylsiloxane (i) in the catalyst package.

[0035] Adhesion promoter (iib) may alternatively or additionally comprise one or more of the following: monoaminoalkoxysilanes such as gamma-aminopropyltriethoxysilane or gamma-aminopropyltrimethoxysilane. [0036] Further suitable adhesion promoters (iib) are reaction products of epoxyalkylalkoxysilanes such as 3- glycidoxypropyltrimethoxysilane with monoamino-substituted alkoxysilanes such as 3- aminopropyltrimethoxysilane and optionally with alkylalkoxysilanes such as methyltrimethoxysilane.

[0037] Typically, these may be used in small amounts e.g. up to 10% by weight of the catalyst package to enhance adhesion but, as previously indicated, their at least partial replacement is advantageous as high loadings of monoamino silane based adhesion promoters (especially primary monoamino silane based adhesion promoters) can cause catalyst instability due to random chain scission of e.g. the unreactive silicones used in the catalyst package. [0038] The total amount of adhesion promoter (ii) i.e. the cumulative amount of adhesion promoter (iia) and optionally adhesion promoter (iib) is in the range of from 10 to 30 weight % (wt. %) of the total weight % (wt. %) of the catalyst package, alternatively 15 to 25 of the total weight % (wt. %) of the catalyst package.

[0039] When present adhesion promoter (iib) may be present in an amount of up to 90% by weight of the cumulative total weight % (wt. %) of adhesion promoter (iia) + adhesion promoter (iib).

[0040] As indicated above, the fact that additional amounts of adhesion promoter (ii) is not required gives the significant benefit of avoiding catalyst package destabilization as levels used are too small to cause this to occur. The diaminosilane adhesion promoters (ii) may be present in the catalyst package in an amount of from 5 to 50 weight %, alternatively 10 to 30 weight %.

[0041] Typically the compositions herein are stored in two or more parts, alternatively two parts prior to use to avoid premature cure. Two-part compositions of the type herein provide a fast, deep cure and as such adhesion promoters are an essential ingredient in such compositions to ensure speed of adhesion and, of course, adhesion to the substrate surface to which the composition is to be applied. It would appear that the diaminosilane adhesion promoters (iia) can replace either totally or partially monoaminosilanes of adhesion promoter (iib) in like for like molar and/or weight amounts and significantly increase speed of adhesion on several difficult to adhere substrates such as metallised glass substrates without the need of any significant increase in the amount of the cumulative amount of total adhesion promoter (ii) required.

[0042] The adhesion promoter (ii) is present in an amount of from 0.1 to 3.75% by weight of the composition when taking parts A and B as combined, alternatively, in an amount of 0.1- 2.5 % by weight of the composition, alternatively, in an amount of 0.20 to 1.0 % by weight of the combined composition.

[0043] Any suitable cross-linker may be used as cross-linker (iii) of the catalyst package. The crosslinker (iii) in the curable composition as hereinbefore described may be one or more silanes or siloxanes which contain silicon bonded hydrolysable groups such as acyloxy groups (for example, acetoxy, octanoyloxy, and benzoyloxy groups); ketoximino groups (for example dimethyl ketoximo, and isobutylketoximino); alkoxy groups (for example methoxy, ethoxy, iso-butoxy and propoxy) and alkenyloxy groups (for example isopropenyloxy and l-ethyl-2-methylvinyloxy).

[0044] In the case of siloxane based cross-linkers the molecular structure can be straight chained, branched, or cyclic.

[0045] Cross-linker (iii) of the catalyst package preferably has at least three or four silicon-bonded condensable (preferably hydroxyl and or hydrolysable) groups per molecule which are reactive with the condensable groups in organopolysiloxane polymer (a). When cross-linker is a silane and when the silane has three silicon-bonded hydrolysable 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 obtained by replacing all or part of the hydrogen in the preceding organic groups with halogen. Preferably, however, the fourth silicon-bonded organic groups is methyl.

[0046] Silanes and siloxanes which can be used as cross-linker (iii) of the catalyst part include alkyltrialkoxysilanes such as methyltrimethoxysilane (MTM) and methyltriethoxysilane, alkenyltrialkoxy silanes such as vinyltrimethoxysilane and vinyltriethoxysilane, isobutyl trimethoxysilane (iBTM). Other suitable silanes include ethyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, alkoxytrioximosilane, alkenyltrioximosilane, , 3,3,3- trifluoropropyltrimethoxysilane, methyltriacetoxysilane, vinyltriacetoxysilane, ethyl triacetoxysilane, di-butoxy diacetoxysilane, phenyl-tripropionoxysilane, methyltris(methylethylketoximo)silane, vinyl-tris-methylethylketoximo)silane, methyltris(methylethylketoximino)silane, methyltris(isopropenoxy)silane, vinyltris(isopropenoxy)silane, ethylpolysilicate, n-propylorthosilicate, tetraethylorthosilicate, tetrapropylorthosilicate, tetraamylorthosilicate and dimethyltetraacetoxydisiloxane.

[0047] The cross-linker (iii) of the catalyst part may also comprise any combination of two or more of the above. The amount of crosslinker present in the total composition (i.e. the total composition when the base component and the catalyst part are mixed together) will depend upon the particular nature of the crosslinker and in particular, the molecular weight of the molecule selected. The compositions suitably contain crosslinker in at least a stoichiometric amount as compared to the organopolysiloxane polymer (a) described above. For example, cross-linker (iii), may comprise from 1 to 30 weight % of the catalyst package, alternatively 1 to 25 weight %, alternatively 5 to 25 weight %.

[0048] The fourth essential ingredient in the catalyst package is a suitable tin based condensation catalyst (iv) which is used to catalyse the cure reaction subsequent to mixing the base component and catalyst package component together. Examples include tin triflates, organic tin metal catalysts such as triethyltin tartrate, tin octoate, tin oleate, tin naphthenate, butyltintri-2-ethylhexoate, tin butyrate, carbomethoxyphenyl tin trisuberate, isobutyltintriceroate, and diorganotin salts especially diorganotin dicarboxylate compounds such as dibutyltin dilaurate, dimethyltin dibutyrate, dibutyltin dimethoxide, dibutyltin diacetate, dimethyltin bisneodecanoate, dibutyltin dibenzoate, stannous octoate, dimethyltin dineodecanoate (DMTDN) and dibutyltin dioctoate. The tin catalyst may be present in an amount of from 0.01 to 3 weight % of the catalyst package; alternatively, 0.1 to 0.5 weight % of the catalyst package.

[0049] Optionally, the catalyst package may also include one or more of, pigments (v) and fillers (vi).

Pigments (v)

[0050] Pigments are utilized to color the composition as required. Any suitable pigment may be utilized providing it is compatible with the composition. In two-part compositions pigments and/or colored (non-white) fillers, e.g. carbon black may be utilized in the catalyst package to color the end sealant product. When present carbon black will function as both filler and colorant.

Fillers (vi)

[0051] One of the fillers used in the base component may also be used in the catalyst package if/when deemed appropriate. Silica, e.g. fumed silica and/or calcium carbonate being preferred. Fillers (vi) may be present in the catalyst package in an amount of from 0 to 50 weight % depending on the mixing ratio of the two-parts of the composition.

[0052] Other additives may be used if necessary non-reinforcing fillers, (as discussed above) pigments, rheology modifiers, other adhesion promoters UV stabilisers, cure modifiers, and fungicides and/or biocides and the like; It will be appreciated that some of the additives are included in more than one list of additives. Such additives would then have the ability to function in all the different ways referred to.

Rheology Modifiers

[0053] Rheology modifiers which may be incorporated in moisture curable compositions according to the invention 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 of the sealant to substrates, particularly plastic substrates.

[0054] Examples of non-dipodal adhesion promoters which may be incorporated in moisture curable compositions according to the invention include alkoxysilanes such as (ethylenediaminepropyl)trimethoxy silane, aminoalkylalkoxy silanes, for example gamma- aminopropyltriethoxysilane or gamma-aminopropyltrimethoxysilane, epoxyalkylalkoxysilanes, for example, 3-glycidoxypropyltrimethoxysilane and , glycidoxypropyltriethoxysilane, mercapto-alkylalkoxysilanes, and reaction products of ethylenediamine with silylacrylates. Isocyanurates containing silicon groups such as 1, 3, 5- tris(trialkoxysilylalkyl) isocyanurates may additionally be used. Further suitable adhesion promoters are reaction products of epoxyalkylalkoxysilanes such as 3- glycidoxypropyltrimethoxysilane with amino-substituted alkoxy silanes such as 3- aminopropyltrimethoxysilane and optionally with alkylalkoxysilanes such as methyltrimethoxysilane.

Biocides

[0055] Biocides may additionally be utilized in the 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:

[0056] Carbamates such as methyl-N-benzimidazol-2-ylcarbamate (carbendazim) and other suitable carbamates, 10, lO'-oxybisphenoxarsine, 2-(4-thiazolyl)-benzimidazole, N-(fluorodichloromethylthio)phthalimide, diiodomethyl 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-l,2-benzisothiazolin-3-one (BBIT). Other biocides might include for example Zinc Pyridinethione, l-(4-Chlorophenyl)-4,4-dimethyl-3-(l,2,4-triazol-l-ylmethyl) pentan-3-ol and/or l-[[2-(2,4-dichlorophenyl)-4-propyl-l,3-dioxolan-2-yl] methyl]-lH- 1,2, 4-triazole.

[0057] 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 be present in an encapsulated form where required such as described in EP2106418.

[0058] When mixed together the total composition of the base component and the catalyst package comprises approximately

18 to 72 weight % of organopolysiloxane polymer (a);

18 to 63 weight % reinforcing fillers (b);

0 to 18 weight % of non-reinforcing fillers (c);

0 to 4.5 weight % low viscosity polymer (d);

3 to 8 weight % of polydialkylsiloxane (i), which is unreactive with polymer (a);

0.5 to 5 weight % of adhesion promotor silane (ii);

0.1 to 3 weight % of cross-linker (iii); and 0.05 to 0.3 weight % of tin based catalyst (iv); with the total weight % of the combined composition being 100 weight %.

[0059] In the case of two-part compositions, the base component comprises:

• 20 to 80 weight % of organopolysiloxane polymer (a); • 20 to 70 weight % reinforcing fillers (b); and

• 0 to 20 weight % of non-reinforcing fillers (c); with the total weight % of the base component being 100 weight %.

[0060] The catalyst package comprises:

• 30 to 80 weight % of polydialkylsiloxane (i), which is unreactive with polymer (a), alternatively 40 to 65 weight % of polydialkylsiloxane (i), which is unreactive with polymer (a);

• 5 to 50 weight % of adhesion promoters (ii), alternatively 15 to 30 weight % of adhesion promoter (ii);

• 1 to 30 weight % of cross-linker (iii), alternatively, 2 to 20 weight %; and

• 0.1 to 3 weight % of tin based catalyst; alternatively, 0.1 to 2.5 weight % of tin based catalyst, alternatively 0.1 to 0.5 weight % of tin based catalyst;

• 0 to 30 weight % colored filler (e.g. carbon black) or pigment, typically 1 to 20 weight % when present;

• 0 to 20 weight % reinforcing filler, alternatively 1 to 10 weight %; with the total weight % of the catalyst package being 100 weight %.

[0061] In the case of two-part sealant compositions, the components of each part are mixed together in amounts within the ranges given above and then the base component composition (sometimes referred to as part A) and the catalyst package composition (sometimes referred to as part B) are inter-mixed in a predetermined ratio e.g. from 15:1 to 1:1, alternatively from 15:1 to 5:1; when the two parts are mixed together. If the intended mixing ratio of the base component : catalyst package is 15:1 or greater then no filler will be generally utilized in the catalyst package. However, if the intended mixing ratio of the base component : catalyst package is less than 15:1 an increasing amount filler may be utilized in the catalyst package up to the maximum of 50 weight % of the catalyst package, if the intended ratio is 1:1. The moisture curable compositions can be prepared by mixing the ingredients employing any suitable mixing equipment.

[0062] Resulting compositions may be employed in a variety of applications, for example as coating, caulking, mold making and encapsulating materials for use with substrates such as glass, aluminium, stainless steel, painted metals, powder-coated metals, and the like. In particular, they are for use in sealant applications needing to be applied to difficult to cure substrates such as metallised glass substrates including low emissivity (low-E) type coated glass substrates and glass substrates having reflective coatings. These may include such coated substrates when used in automotive, construction and/or structural glazing and/or insulating glazing applications. For example, an insulating glass unit and or building facade element e.g. a shadow box and/or structural glazing unit and/or a gas filled insulation construction panel, which in each case may be sealed with a silicone sealant composition as hereinbefore described. Other potential applications include solar, automotive, electronics and industrial assembly and maintenance applications.

[0063] In the case of silicone sealant compositions 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 silicone composition as hereinbefore described, and either b) mixing and applying the 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 silicone composition and curing the silicone composition. Examples

[0064] The following examples are provided to show that sealant compositions containing the catalyst package as provided herein can be utilised to gain an improved speed of adhesion without the need for high levels of adhesion promoters on difficult to cure substrates such as metallised glass substrates. All viscosities mentioned were measured in accordance with Corporate test method CTM 0050, which is publicly available, and which is based on ASTM D 1084-16 method B, using a Brookfield ^® HBDV-III Ultra Rheometer equipped with a cone-and-plate geometry using spindle CP-52.

[0065] A series of examples in support of the disclosure herein together with a series of comparative examples were prepared. A standard part A or base component composition was used for all examples. The standard part A or base component composition consisted of 50% by weight of a dimethyl silanol terminated polydimethylsiloxane polymer having a viscosity of about 5,600mPa.s at 25°C and 50 % by weight of a hydrophobically treated precipitated calcium carbonate having a BET surface area of 21m ² /g in accordance with the BET method (ISO 9277: 2010).

[0066] Several catalyst package formulations were prepared. Table la depicts the formulations of the examples supporting the disclosure herein which contain only adhesion promoter (iia) or partially adhesion promoter (iib) and partially adhesion promoter (iib) and Table lb depicts a series of comparative catalyst packages which do not contain the adhesion promoter (iia).

Table la Composition of Examples 1-4 in accordance with the invention (wt.%)

Table lb Composition of Comparatives 1-4 in accordance with the invention (wt.%) [0067] The compositions depicted in Tables la and lb were prepared using the following process.

Alkyl-terminated diorganopolysiloxane (polymer), carbon black (optional pigment/non-reinforcing filler), and fumed silica (reinforcing filler) were compounded into a base in a one-gallon high-shear Ross mixer by first mixing the polymer and about half the carbon black. Once sufficiently mixed the remaining carbon black was added. The resulting mixture was then thoroughly stirred before the introduction of about 50% by weight of the fumed silica. This was mixed into the composition followed by the remaining fumed silica filler. The resulting base component composition was then thoroughly mixed, partially under vacuum.

[0068] The catalyst package was then prepared by mixing the above base component composition with an appropriate amount of a slurry of the remaining ingredients and the mixture was thoroughly mixed initially under nitrogen and at the end of the process under vacuum.

[0069] The resulting material (i.e. part B or catalyst package) was mixed with the Part A base component composition comprised of 50% precipitated calcium carbonate, and 50% hydroxyl- terminated polydimethylsiloxane as hereinbefore described in a ratio of Part A : part B of 10 : 1 in a 300 Tall Speedmixer cup, then mixing on a DAC 600.2 VAC-P Speedmixer for one minute at 800 rpm. The material was then scraped from the bottom and sides of the cup and mixed for a further 20 seconds at 1200 rpm. Finally, the material was transferred to a suitable storage tube via a hand- operated cup press, and immediately applied to the substrates.

[0070] Peel strength or adhesion-in-peel test were undertaken according to ASTM C794-18. The substrates on to which sealant was applied were glass substrates which had metallised coatings that are known to be difficult to adhere to. The substrates were prepared by wiping twice with isopropyl alcohol (IP A) and air dried. Stainless steel screens (20x20x0.016”), having a 0.5 inch (1.27 cm) width, were prepared by cleaning with xylene and priming with DOWSIL™ 1200 OS primer and drying 24 hours after each step. [0071] A bead of mixed sealant was applied to the substrate and drawn down to 1/8” thickness.

Next, the screen was lightly pressed into the sealant, and a second bead of sealant was applied onto the screen and drawn down to ¼” (0.32 cm) total thickness. All samples were initially cured for seven days at room temperature and 50% relative humidity (RH). Prior to testing, a fresh score mark was created with a knife at the substrate/sealant interface just below the screen. Adhesion-in- Peel was measured by pulling the screen 180° at 2.0 in/min using a TA HD Plus Texture Analyser. The results for the samples tested are provided in Tables 2a - 2d.

Table 2a: 24 hr Peel strength Test (N/mm) Table 2b 7 day Peel Strength test (N/mm)

Table 2c: 24 hr Peel Strength test (N/mm) Table 2d: 7 day Peel Strength test (N/mm)

[0072] The presence of the diaminosilane in the compositions resulted in a surprising increase in speed of adhesion as can be seen when comparing the results of Tables 2a to 2d above. Whilst the speed of adhesion was improved utilizing the (iia) adhesion promotors other standard physical properties e.g. tested in accordance with in accordance with ASTM D2240-15 (shore A), ASTM D412-16 (tensile strength, elongation, modulus) and ASTM D 624 (tear strength) were not negatively affected. Table 3a 7 Day physical Testing Results

Table 3b 7 Day physical Testing Results Table 3c 28 Day physical Testing Results

Table 3d 28 Day physical Testing Results

[0073] In a further set of experiments the catalyst package was prepared in the absence of the pigment and filler ingredients depicted in Table la and it will be seen that , again excellent adhesion properties are observed. Examples la to 4a are using analogous catalyst packages as depicted in Table la but with the filler and pigment removed. The composition once prepared and then mixed with the part A or base component composition was tested in an analogous fashion on the same substrates as described above and the results for the sealant composition prepared and applied are depicted in Table 4a and 4b.

Table 4a - 24 hr Peel strength Test (N/mm) Table 4b 7 day Peel strength Test (N/mm)