Silicone coatings

Abstract

This disclosure relates to an unscoured airbag fabric hydrosilylation curable silicone rubber coating composition, a method for coating an unscoured airbag fabric with said composition and an unscoured airbag fabric coated with said composition.

Description

SILICONE COATINGS CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefits of U.S. Provisional Patent Application No. 63 / 727696 filed on 4 December 2024 and U.S. Provisional Patent Application No. 63 / 663204 filed on 24 June 2024 under 35 U.S.C. §119 (e). U.S. Provisional Patent Application No.63 / 727696 and U.S. Provisional Patent Application No.63 / 663204 are hereby incorporated by reference. TECHNICAL FIELD

[0002] This disclosure relates to an unscoured airbag fabric hydrosilylation curable silicone rubber coating composition, a method for coating an unscoured airbag fabric with said composition and an unscoured airbag fabric coated with said composition. INTRODUCTION

[0003] Inflatable safety restraint devices, especially airbags are widely used to cushion vehicle occupants in the event of collisions and accidents. They are designed to protect drivers and passengers from being injured between an initial impact and further impacts, by their inflation in within 0.02-0.12 seconds of the initial impact during a traffic accident. Inflatable safety restraint devices such as airbags, generally consist of a textile or fabric (hereafter referred to as a fabric) bag (sometimes referred to as a cushion), a sensor and a means of inflation. In the event of an accident, a sensor within a vehicle identifies an abnormal deceleration and triggers the inflator causing an effectively immediate inflation of the airbag. Expanding gases travel through conduits and inflate the airbag(s), to cushion the vehicle occupant (driver or passenger) to protect them from any further harmful impact within the interior of the vehicle, e.g., a car.

[0004] The airbags may be made from flat fabric pieces which are coated and then sewn together to provide sufficient mechanical strength or may be woven in one piece (generally referred to as “one-piece woven” or OPW) with integrally woven seams.

[0005] Airbag fabric is typically made from woven polyester yarns such as polyethylene terephthalate (PET) or woven polyamide yarns such as nylon-6,6. Prior to weaving the airbag fabric, the e.g., polyester or polyamide yarn is coated with one or more sizing and / or spin finishing agents to aid in high-speed weaving processes.

[0006] Sizing agents are applied to the polyester or polyamide yarn prior to the weaving process to function as a protective coating to change the absorption and wear characteristics of initially the yarn and subsequently the woven fabric. Spin finishing agents are utilisedon, for example, polyester and / or polyamide, yarns and fibres at the last stage of the fibre production. They are used to form thin uniform coatings on the fibre surface to e.g., reduce surface friction and flexural rigidity of the, in the present case, airbag fabric material. Spin finishing agents may include a variety of ingredients such as, but not limited to, lubricants, emulsifiers, antistatic agents, bactericides and antioxidants.

[0007] Traditionally once the airbag fabric has been woven the sizing and spin finishing agents are removed from the yarn surfaces by a scouring process (sometimes referred to as a de-sizing process). The scouring process involves the fabric being washed and heated in a process to remove the sizing and spin finishing agents. Scouring removes soluble and insoluble impurities found in fabrics as natural, added and adventitious impurities: for example, oils, waxes, fats, vegetable matter, as well as dirt. Removing these contaminants through scouring prepares the fabric for additional processes, in particular in the case of airbag materials coating processes.

[0008] Airbags and / or airbag fabrics benefit from the application of silicone coatings in a number of ways. These include: 1) improved thermal protection from hot gases and particulates (600oC to 1,000oC) generated during airbag expansion using for pyrotechnic generators; 2) improved flame-resistance of fabric; 3) improved resistance to bag deflation; 4) improved resistance to stresses when airbag cushions deployed; and 5) the softness and lightness of silicone coating provide airbags with very good flexibility, enabling them to be folded into a more compact module.

[0009] Silicone coatings used on airbags are not only designed to prevent air leakage but are also designed to keep the airbags flexible and resistant to temperature fluctuations, aging and abrasion. They need such properties because, for example, an airbag may remain unused for an extended period of time before a collision triggers deployment. This requires the silicone coating to be very stable over time in order to prevent the airbag from becoming stuck and to ensure smooth deployment even after many years. Furthermore, in order to remain functional throughout the lifetime of the vehicle in which they are stored they need to be strongly adhered to the textile and / or fabric with which the airbag is made.

[0010] Ideally, the scouring step would be eliminated completely because it is resource (water, energy, and time) intensive and has negative environmental and economic consequences. However, the sizing and / or spin finishing agents with which the yarn is treated before weaving are typically detrimental to LSR adhesion onto the resulting airbag fabric.

[0011] However, silicone adhesion to unscoured airbag fabric i.e., with a surface covered in residual spinning and sizing agents is poor and unable to meet airbag safety requirements, as necessitated by industry standards e.g., scrub resistance test methods for coatings, particularly after prolonged exposure to heat and humidity.

[0012] Sewn flat fabric airbags are generally assembled with the coated fabric surface at the inside of the airbag but may be coated on the insider and / or outside. One-piece woven airbags are coated on the outside of the airbag. Some airbags are designed to retain gas pressure after deployment, so they remain inflated for longer periods of time after a collision or the like, e.g., side-curtain airbags. These tend to be, but are not exclusively, one-piece woven airbags.

[0013] Today, it is generally compulsory to have several airbags in vehicles as a means of providing safety to the occupants in the event of a collision. They include frontal airbags, front-centre airbags, side airbags, side-curtain airbags, thorax airbags, and / or knee airbags. Typically, the airbags are concealed within the vehicle trim to be invisible during normal vehicle operation.

[0014] For example, frontal airbags may be installed in the steering wheel on the driver's side of car and in the dashboard on the passenger side of a car. They are provided to function as a cushion at a point of impact especially in collisions with the front or back of the vehicle. They exhibit relatively high air permeabilities to allow the expanded airbag to quickly deflate after the initial impact. Typically, these airbags are flat fabric pieces sewn together.

[0015] Side-curtain airbags are increasingly utilized and are most often mounted within the headliner above the doors and windows and deploy along the side window from the vicinity of the ceiling to protect vehicle occupants from a side collision and consequent rollover incidents (where the vehicle tips over onto its side or upside-down or flips over more than once). Because of this, side-curtain airbags, are designed to retain their inflated state for a long duration (for example, exhibiting a retention of at least 50% of the initial pressure after 5 seconds subsequent to high pressure inflation) i.e., they need to retain large amounts of gas, as well as high gas pressures, throughout the longer time periods of the entire potential rollover. They generally unroll from packing containers stored within the roofline along the side windows of an automobile (and thus have a back and front side only). Side-curtain airbags therefore not only provide cushioning effects but also provide protection from broken glass and other debris.

[0016] One-piece woven type airbags are usually (but not exclusively) used for side- curtain airbags in order to provide the low permeability (and thus longer gas escape times) necessary for side-curtain airbags.

[0017] Consequently, hydrosilylation curable silicone rubber coating compositions for treating textiles and fabrics often contain adhesion promoters to enhance adhesion between the coating and the textile / fabric to which they have been applied.

[0018] Development of new adhesion packages for liquid silicone rubber airbag coatings that maintain strong adhesion to unscoured fabrics even after exposure to heat and humidity would bring both economic and environmental benefits. SUMMARY

[0019] There is provided herein an unscoured airbag fabric hydrosilylation curable silicone rubber coating composition comprising: (a) an organopolysiloxane polymer having a zero-shear viscosity of between 100 and 200,000mPa.s inclusive at 25 ºC, and at least two unsaturated groups per molecule, which unsaturated groups are selected from alkenyl groups, alkynyl groups or a mixture thereof; (b) optionally one or more fillers; (c) an organosilicon compound having at least two, or at least three Si-H groups per molecule; (d) a hydrosilylation cure catalyst; (e) an organosiloxane adhesion promoter having the structure (e-1): Z2–[X - Si(CH3)2]u-O -Si (Ph)2– O – [Si(CH3)2– X]u– Z2Where each X is a linear or branched alkylene group having from 1 to 6 carbons; Each Z2is a cyclic siloxane of the structure =(Si(R1) - O)-(Si(R1)(R2) -O)m- where each R1is an independently selected monovalent hydrocarbyl group, (alternatively an alkyl group) and each R2is independently selected from the group consisting of hydrogen (H) or an organic moiety comprising an epoxy group, m is from 3 to 20 and where each u is 0 or 1; and wherein each molecule contains a mixture of R2groups consisting of one or more organic moieties comprising an epoxy group and one or more hydrogens (H); and (f) a chelated metal condensation catalyst wherein the metal is selected from one or more of titanium, zirconium, aluminum, vanadium, chromium, scandium, manganese, iron, cobalt, nickel, copper and zinc.

[0020] There is also provided herein a coated unscoured airbag fabric comprising a unscoured airbag fabric coated with the cured product of an unscoured airbag fabric hydrosilylation curable silicone rubber coating composition comprising:(a) an organopolysiloxane polymer having a zero-shear viscosity of between 100 and 200,000mPa.s inclusive at 25 ºC, and at least two unsaturated groups per molecule, which unsaturated groups are selected from alkenyl groups, alkynyl groups or a mixture thereof; (b) optionally one or more fillers; (c) an organosilicon compound having at least two or at least three Si-H groups per molecule; (d) a hydrosilylation cure catalyst; (e) an organosiloxane adhesion promoter having the structure (e-1) described above; and (f) a chelated metal condensation catalyst wherein the metal is selected from one or more of titanium, zirconium, aluminum, vanadium, chromium, scandium, manganese, iron, cobalt, nickel, copper and zinc.

[0021] There is also provided herein a method of coating unscoured airbag fabric with an unscoured airbag fabric hydrosilylation curable silicone rubber coating composition comprising the steps of mixing the components of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition: comprising: (a) an organopolysiloxane polymer having a zero-shear viscosity of between 100 and 200,000mPa.s inclusive at 25 ºC, and at least two unsaturated groups per molecule, which unsaturated groups are selected from alkenyl groups, alkynyl groups or a mixture thereof; (b) optionally one or more fillers; (c) an organosilicon compound having at least two or at least three Si-H groups per molecule; (d) a hydrosilylation cure catalyst; (e) an organosiloxane adhesion promoter having the structure (e-1) described above; and ( f) a chelated metal condensation catalyst wherein the metal is selected from one or more of titanium, zirconium, aluminum, vanadium, chromium, scandium, manganese, iron, cobalt, nickel, copper and zinc by applying the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition onto an unscoured airbag fabric and curing the composition to form an unscoured airbag fabric.

[0022] There is also provided a use of (e) an organosiloxane adhesion promoter having the structure (e-1): Z2–[X - Si(CH3)2]u -O -Si (Ph)2 – O – [Si(CH3)2 – X]u – Z2Where each X is a linear or branched alkylene group having from 1 to 6 carbons; Each Z2is a cyclic siloxane of the structure =(Si(R1) - O)-(Si(R1)(R2) -O)m- where each R1is an independently selected monovalent hydrocarbyl group, (alternatively an alkyl group) and each R2is independentlyselected from the group consisting of hydrogen (H) or an organic moiety comprising an epoxy group, m is from 3 to 20 and where each u is 0 or 1; and wherein each molecule contains a mixture of R2groups consisting of one or more organic moieties comprising an epoxy group and one or more hydrogens (H); and (f) a chelated metal condensation catalyst wherein the metal is selected from one or more of titanium, zirconium, aluminum, vanadium, chromium, scandium, manganese, iron, cobalt, nickel, copper and zinc; in an unscoured airbag fabric hydrosilylation curable silicone rubber coating composition for coating an unscoured airbag fabric which composition otherwise comprises: (a) an organopolysiloxane polymer having a zero-shear viscosity of between 100 and 200,000mPa.s inclusive at 25 ºC, and at least two unsaturated groups per molecule, which unsaturated groups are selected from alkenyl groups, alkynyl groups or a mixture thereof; (b) optionally one or more fillers; (c) an organosilicon compound having at least two or at least three Si-H groups per molecule; (d) a hydrosilylation cure catalyst. DETAILED DESCRIPTION

[0023] The unscoured airbag fabric hydrosilylation curable silicone rubber coating compositions comprise the following components: Component (a)

[0024] Component (a) of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition is one or more organopolysiloxane polymers having a zero- shear viscosity of between 100 and 200,000mPa.s inclusive at 25 ºC, and at least two unsaturated groups per molecule, which unsaturated groups are selected from alkenyl groups, alkynyl groups or a mixture thereof.

[0025] Each organopolysiloxane polymer of component (a) comprises multiple siloxy units, of formula (I): R’aSiO(4-a) / 2(I); The subscript “a” is 0, 1, 2 or 3.

[0026] Siloxy units may be described by a shorthand (abbreviated) nomenclature, namely - "M," "D," "T," and "Q", when R’ is as described above, alternatively an alkyl group, typically a methyl group. The M unit corresponds to a siloxy unit where a = 3, that is R’3SiO1 / 2; the D unit corresponds to a siloxy unit where a = 2, namely R’2SiO2 / 2; the T unit corresponds to a siloxy unit where a = 1, namely R’1SiO3 / 2; the Q unit corresponds to a siloxy unit where a = 0, namely SiO4 / 2. The organopolysiloxane polymer of component (a) is substantially linear but may contain a proportion of branching due to the presence of Tunits (as previously described) within the molecule, hence the average value of a in structure (I) is about 2.

[0027] The unsaturated groups of component (a) may be positioned either terminally or pendently on the organopolysiloxane polymer, or in both locations. The unsaturated groups of component (a) may be alkenyl groups or alkynyl groups as described above. Each alkenyl group, when present, may comprise for example from 2 to 30, alternatively 2 to 24, alternatively 2 to 20, alternatively 2 to 12, alternatively 2 to 10, and alternatively 2 to 6 carbon atoms. When present the alkenyl groups may be exemplified by, but not limited to, vinyl, allyl, methallyl, propenyl, and hexenyl and cyclohexenyl groups. Each alkynyl group, when present, may also have 2 to 30, alternatively 2 to 24, alternatively 2 to 20, alternatively 2 to 12, alternatively 2 to 10, and alternatively 2 to 6 carbon atoms. Examples of alkynyl groups may be exemplified by, but not limited to, ethynyl, propynyl, and butynyl groups. Preferred examples of the unsaturated groups of component (a) include vinyl, propenyl, isopropenyl, butenyl, allyl, and 5-hexenyl.

[0028] In formula (I), each R’, other than the unsaturated groups described above, is independently selected from an aliphatic hydrocarbyl group, a substituted aliphatic hydrocarbyl group, an aromatic group or a substituted aromatic group. Each aliphatic hydrocarbyl group may be exemplified by, but not limited to, alkyl groups having from 1 to 20 carbons per group, alternatively 1 to 15 carbons per group, alternatively 1 to 12 carbons per group, alternatively 1 to 10 carbons per group, alternatively 1 to 6 carbons per group or cycloalkyl groups such as cyclohexyl. Specific examples of alkyl groups may include methyl, ethyl, propyl, pentyl, octyl, undecyl, and octadecyl groups, alternatively methyl and ethyl groups. Substituted aliphatic hydrocarbyl group are preferably non-halogenated substituted alkyl groups.

[0029] The aliphatic non-halogenated organyl groups are exemplified by, but not limited to alkyl groups as described above with a substituted group such as suitable nitrogen containing groups such as amido groups, imido groups; oxygen containing groups such as polyoxyalkylene groups, carbonyl groups, alkoxy groups and hydroxyl groups. Further organyl groups may include sulfur containing groups, phosphorus containing groups, boron containing groups. Examples of aromatic groups or substituted aromatic groups are phenyl groups and substituted phenyl groups with substituted groups as described above.

[0030] Component (a) may, for example, be selected from polydimethylsiloxanes, alkylmethylpolysiloxanes, alkylarylpolysiloxanes or copolymers thereof (where reference to alkyl means any suitable alkyl group, alternatively an alkyl group having two or morecarbons) providing each polymer has a zero-shear viscosity of organopolysiloxane polymer (a) should be between 100 and 200,000mPa.s inclusive at 25 ºC.

[0031] Hence component (a) may, for the sake of example, be: a dialkylalkenyl terminated polydimethylsiloxane, e.g., dimethylvinyl terminated polydimethylsiloxane; a dialkylalkenyl terminated dimethylmethylphenylsiloxane, e.g., dimethylvinyl terminated dimethylmethylphenylsiloxane; a trialkyl terminated dimethylmethylvinyl polysiloxane; a dialkylvinyl terminated dimethylmethylvinyl polysiloxane copolymer; a dialkylvinyl terminated methylphenylpolysiloxane, a dialkylalkenyl terminated methylvinylmethylphenylsiloxane; a dialkylalkenyl terminated methylvinyldiphenylsiloxane; a dialkylalkenyl terminated methylvinyl methylphenyl dimethylsiloxane; a trimethyl terminated methylvinyl methylphenylsiloxane; a trimethyl terminated methylvinyl diphenylsiloxane; or a trimethyl terminated methylvinyl methylphenyl dimethylsiloxane. In each case component (a) the zero-shear viscosity of organopolysiloxane polymer (a) should be between 100 and 200,000mPa.s inclusive at 25 ºC, alternatively from 1000 to 150,000mPa.s at 25 ºC, alternatively, from 1000mPa.s to 125,000mPa.s, alternatively from 1000mPa.s to 100,000mPa.s at 25 ºC.

[0032] Unless otherwise indicated all viscosity measurements given are zero-shear viscosity (ηo) values, obtained by extrapolating to zero the value taken at low shear rates (or simply taking an average of values) in the limit where the viscosity-shear rate curve is rate- independent, which is a test-method independent value provided a suitable, properly operating rheometer is used. For example, the zero-shear viscosity of a substance at 25 °C may be obtained by using commercial rheometers such as an Anton-Parr MCR-301 rheometer or a TA Instruments AR-2000 rheometer equipped with cone-and-plate fixtures of suitable diameter to generate adequate torque signal at a series of low shear rates, such as 0.01 s-1, 0.1 s-1and 1.0 s-1while not exceeding the torque limits of the transducer.

[0033] Typically, the alkenyl and / or alkynyl content, e.g., vinyl content of the polymer is from 0.01 to 3 % for each organopolysiloxane polymer containing at least two silicon- bonded alkenyl groups per molecule of component (a), alternatively from 0.01 to 2.5 % of component (a), alternatively from 0.001 to 2.0 %, alternatively from 0.01 to 1.5 % of component (a) of the or each organopolysiloxane polymer containing at least two unsaturated groups per molecule, which unsaturated groups are selected from alkenyl groups, alkynyl groups or a mixture thereof per molecule of component (a). Thealkenyl / alkynyl content of component (a) is determined using quantitative infra-red analysis in accordance with ASTM E168.

[0034] Component (a) may be present in the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition in an amount of from 40 wt. % to about 80 wt. % of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition, alternatively from 45 to 80 wt. % of the composition, alternatively from 50 to 80 wt. % of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition. Typically, component (a) is present in an amount which is the difference between 100 wt. % and the cumulative wt. % of the other components / ingredients of the composition. Optional Component (b)

[0035] Component (b) of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition is optional and when present is one or more fillers. When present, the fillers may comprise one or more reinforcing fillers, one or more non- reinforcing fillers, one or more flame retardant fillers or a mixture thereof.

[0036] When present, component (b) may comprise one or more reinforcing fillers, the reinforcing fillers may comprise fumed silica, precipitated silica or a mixture thereof. Finely divided forms of silica are preferred. Reinforcing silica fillers typically have a relatively high surface area, typically at least 50 m² / g (BET method in accordance with ISO 9277: 2010) are utilized. For example, fillers, (e.g., fumed silica) having surface areas of from 50 - 450m2 / g, alternatively, 50 – 400m2 / g alternatively from 50 to 300 m² / g, alternatively 100 - 300m2 / g (BET method in accordance with ISO 9277: 2010) are typically used.

[0037] Typically, such reinforcing filler(s) is / are naturally hydrophilic (e.g., untreated) silica fillers, and are therefore treated with a treating agent to render it / them hydrophobic. These surface modified reinforcing fillers do not clump and can be homogeneously incorporated into organopolysiloxane polymer (a), as the surface treatment makes the fillers easily wetted by organopolysiloxane polymer (a).

[0038] Typically, said reinforcing fillers may be surface treated with any low molecular weight organosilicon compounds disclosed in the art applicable to prevent creping of organosiloxane compositions during processing. For example, they may be treated with organosilanes, polydiorganosiloxanes, organosilazanes, short chain siloxane diols such as dimethyl methylvinyl siloxane diols, fatty acids or fatty acid esters such as stearates. Once treated the fillers are rendered hydrophobic and consequently easier to handle and to obtaina homogeneous mixture with the other ingredients, particularly component (a). Specific examples of treating agents include but are not restricted to silanol terminated trifluoropropylmethyl siloxane, silanol terminated vinylmethylsiloxane, tetramethyldi(trifluoropropyl)disilazane, tetramethyldivinyl disilazane, hexamethyl disilazane (HMDZ), silanol terminated MePh siloxane (where Me denotes methyl and Ph denotes phenyl), liquid hydroxyl-terminated polydiorganosiloxane containing an average from 2 to 20 repeating units of diorganosiloxane in each molecule, hexaorganodisiloxane, hexaorganodisilazane. A small amount of water can be added together with the silica treating agent(s) as a processing aid.

[0039] The reinforcing silica fillers may be pre-treated prior to introduction into the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition r may be treated in situ (i.e., in the presence of at least a portion of the other ingredients of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition herein by blending these ingredients together at room temperature or above until the filler is completely treated. Typically, when present untreated reinforcing filler is treated in situ with a treating agent in the presence of organopolysiloxane polymer (a) which results in the preparation of a silicone rubber base material which can subsequently be mixed with other ingredients.

[0040] When present in or as component (b), the reinforcing filler(s) is / are present in the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition in an amount of from 1.0 to 50wt. %. of the composition, alternatively of from 1 to 30wt. %. of the composition, alternatively of from 2.5 to 30wt. %. of the composition, alternatively of from 3.5 to 25wt. %. of the composition.

[0041] The one or more fillers of component (b) may alternatively or also include one of more non-reinforcing fillers such as, for example, crushed quartz, diatomaceous earths, barium sulphate, iron oxide, precipitated calcium carbonate, ground calcium carbonate, titanium dioxide and carbon black, talc and 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, magnesium hydroxide e.g., brucite, graphite, copper carbonate, e.g., malachite, nickel carbonate, e.g., zarachite, barium carbonate, e.g., witherite and / or strontium carbonate e.g., strontianite.

[0042] Other non-reinforcing fillers may include 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, forsteriteand 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. Ring silicates may be utilized as non-reinforcing fillers, these include 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]. Sheet silicates may alternatively or additionally be used as non- reinforcing fillers where appropriate 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. Such non-reinforcing may be hydrophobically treated in a similar fashion to the reinforcing fillers described above if desired or required.

[0043] A small amount of water can be added together with the treating agent(s) as a processing aid. Component (c)

[0044] Component (c) of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition functions as a cross-linker and is provided in the form of an organosilicon compound having an average of at least two or an average of at least three Si- H groups per molecule. The molecular configuration of the organosilicon compound having an average of at least two or an average of at least three Si-H groups per molecule (c) is not specifically restricted, and it can be a silane or a straight chain, branched (a straight chain with some branching through the presence of T units) or cyclic siloxane polymer or be silicone resin based.

[0045] Component (c) is typically a linear or branched siloxane or a silicone resin. Component (c) normally contains an average of three or more silicon-bonded hydrogen atoms so that the silicon bonded hydrogen atoms can react with the unsaturated groups (alkenyl and / or alkynyl groups) of component (a) and / or the rest of the composition to form a network structure therewith and thereby cure the composition. Some or all of Component (c) may alternatively have two silicon bonded hydrogen atoms per molecule. However, such a molecule is only used as the sole cross-linker when e.g., polymer (a) has greater than two unsaturated groups per molecule in which case a network can be produced during the cure process. Otherwise, when component (c) partially comprises, molecules having an average of two silicon bonded hydrogen atoms per molecule, said molecules may function as a chain extender.

[0046] While the molecular weight of component (c) is not specifically restricted, the viscosity may be measured as described above in respect to component (a). However, in the case of very low viscosities they may be measured using a glass capillary viscometer in accordance with ASTM D-445.

[0047] Silicon-bonded organic groups used in component (c) may be exemplified by alkyl groups such as methyl, ethyl, propyl, n-butyl, t-butyl, pentyl, hexyl; aryl groups such as phenyl tolyl, xylyl, or similar aryl groups; 3-chloropropyl, 3,3,3-trifluoropropyl, or similar halogenated alkyl group, preferred alkyl groups having from 1 to 6 carbons, especially methyl ethyl or propyl groups or phenyl groups. Preferably the silicon-bonded organic groups used in component (c) are alkyl groups, alternatively methyl, ethyl or propyl groups.

[0048] Examples of the organosilicon compound having an average of at least two or an average of at least three Si-H groups per molecule (c) include but are not limited to: (a’) trimethylsiloxy-terminated methylhydrogenpolysiloxane, (b’) trimethylsiloxy-terminated polydimethylsiloxane-methylhydrogensiloxane, (c’) dimethylhydrogensiloxy-terminated dimethylsiloxane-methylhydrogensiloxane copolymers, (d’) dimethylsiloxane-methylhydrogensiloxane cyclic copolymers, (e’) copolymers and / or silicon resins consisting of (CH3)2HSiO1 / 2units, (CH3)3SiO1 / 2units and SiO4 / 2 units, (f’) copolymers and / or silicone resins consisting of (CH3)2HSiO1 / 2 units and SiO4 / 2 units, (g’) Methylhydrogensiloxane cyclic homopolymers having between 3 and 10 silicon atoms per molecule, (h’) an Si-H terminated methylhydrosiloxane-phenylmethylsiloxane co-polymer having a zero-shear viscosity of from 50 to 300 cSt and 30 to 75 mol % of phenylmethylsiloxane units;alternatively, component (c), the cross-linker, may be a filler, e.g., silica treated with one of the above, and mixtures thereof.

[0049] In one embodiment the component (c) is selected from a methylhydrogenpolysiloxane capped at both molecular terminals with trimethylsiloxy groups; a copolymer of a methylhydrogensiloxane and a dimethylsiloxane capped at both molecular terminals with trimethylsiloxy groups; dimethylsiloxane capped at both molecular terminals with dimethylhydrogensiloxy groups; a copolymer of a methylhydrogensiloxane and a dimethylsiloxane capped at both molecular terminals with dimethylhydrogensiloxy groups.

[0050] The cross-linker (c) is generally present in the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition such that the molar ratio of the silicon-bonded hydrogen atoms in component (c) to the total unsaturated groups selected from alkenyl and / or alkynyl groups in the composition is from 0.5:1 to 20:1. When this ratio is less than 0.5:1, a well-cured composition will not be obtained. When the ratio exceeds 20:1, there is a tendency for the hardness of the cured unscoured airbag fabric hydrosilylation curable silicone rubber coating composition to increase when heated.

[0051] The molar ratio of silicon-bonded hydrogen atoms of component (c) to total unsaturated groups selected from alkenyl and / or alkynyl groups in the organopolysiloxane (a) is preferably at least 1:1 and can be up to 8:1 or 10:1. Most preferably the molar ratio of Si-H groups to aliphatically unsaturated groups is in the range from 1.1:1 to 5:1.

[0052] The silicon-bonded hydrogen (Si-H) content of component (c) is determined using quantitative infra-red analysis in accordance with ASTM E168. In the present instance the silicon-bonded hydrogen to alkenyl (vinyl) and / or alkynyl ratio is important when relying on a hydrosilylation cure process. Generally, this is determined by calculating the total weight % of alkenyl groups in the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition e.g., vinyl [V] and the total weight % of silicon bonded hydrogen [H] in the composition and given the molecular weight of hydrogen is 1 and of vinyl is 27 the molar ratio of silicon bonded hydrogen to vinyl is 27[H] / [V].

[0053] Typically, dependent on the number of unsaturated groups in component (a) and the rest of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition as well as the number of Si-H groups in component (c), component (c) will be present in an amount of from 0.1 to 15 wt. % of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition, alternatively 0.1 to 12.5 wt. % of the composition, alternatively 0.25 to 12.5wt. %, further alternatively from 2.5 wt. % to 12.5 wt. % of the composition, alternatively from 2.5 wt. % to 10 wt. % of the composition. For the avoidance of doubt component (c) and component (e) are different. (d) Hydrosilylation catalyst

[0054] Component (d) of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition is a hydrosilylation catalyst comprising or consisting of a platinum group metal or a compound thereof. These are usually selected from catalysts of the platinum group of metals (platinum, ruthenium, osmium, rhodium, iridium and palladium), or a compound of one or more of such metals. Alternatively, platinum and rhodium compounds are preferred due to the high activity level of these catalysts in hydrosilylation reactions, withplatinum compounds most preferred. In a hydrosilylation (or addition) reaction, a hydrosilylation catalyst such as component (d) herein catalyses the reaction between an unsaturated group, usually an alkenyl group e.g., vinyl with Si-H groups.

[0055] The hydrosilylation catalyst of component (d) can be a platinum group metal, a platinum group metal deposited on a carrier, such as activated carbon, metal oxides, such as aluminum oxide or silicon dioxide, silica gel or powdered charcoal, or a compound or complex of a platinum group metal. Preferably the platinum group metal is platinum. Examples of preferred hydrosilylation catalysts of component (d) are platinum based catalysts, for example, platinum black, platinum oxide (Adams catalyst), platinum on various solid supports, chloroplatinic acids, e.g., hexachloroplatinic acid (Pt oxidation state IV) (Speier catalyst), chloroplatinic acid in solutions of alcohols e.g., isooctanol or amyl alcohol (Lamoreaux catalyst), and complexes of chloroplatinic acid with ethylenically unsaturated compounds such as olefins and organosiloxanes containing ethylenically unsaturated silicon- bonded hydrocarbon groups, e.g., tetra-vinyl-tetramethylcyclotetrasiloxane-platinum complex (Ashby catalyst). Soluble platinum compounds that can be used include, for example, the platinum-olefin complexes of the formulae (PtCl2.(olefin)2and H(PtCl3.olefin), preference being given in this context to the use of alkenes having 2 to 8 carbon atoms, such as ethylene, propylene, isomers of butene and of octene, or cycloalkanes having 5 to 7 carbon atoms, such as cyclopentene, cyclohexene, and cycloheptene.

[0056] Other soluble platinum catalysts are, for the sake of example a platinum- cyclopropane complex of the formula (PtCl2C3H6)2, the reaction products of hexachloroplatinic acid with alcohols, ethers, and aldehydes or mixtures thereof, or the reaction product of hexachloroplatinic acid and / or its conversion products with vinyl- containing siloxanes such as methylvinylcyclotetrasiloxane in the presence of sodium bicarbonate in ethanolic solution. Platinum catalysts with phosphorus, sulfur, and amine ligands can be used as well, e.g., (Ph3P)2PtCl2; and complexes of platinum with vinylsiloxanes, such as sym-divinyltetramethyldisiloxane (Karstedt’s catalyst).

[0057] Hence, specific examples of suitable platinum-based catalysts of component (d) include: (i’) complexes of chloroplatinic acid with organosiloxanes containing ethylenically unsaturated hydrocarbon groups are described in US 3,419,593; (ii’) chloroplatinic acid, either in hexahydrate form or anhydrous form;(iii’) a platinum-containing catalyst which is obtained by a method comprising reacting chloroplatinic acid with an aliphatically unsaturated organosilicon compound, such as divinyltetramethyldisiloxane; (iv’) alkene-platinum-silyl complexes as described in US Pat. No.6,605,734 such as (COD)Pt(SiMeCl2)2where “COD” is 1,5-cyclooctadiene; (v’) Karstedt’s catalyst is a Pt2(divinyl tetramethyl disiloxane)3 complex typically containing from 30 to 50 wt. % platinum metal in the complex. It is typically introduced into a silicone rubber composition in a premix with a vinyl siloxane polymer. The combination being from about from 0.25 to 2.0 wt. % of the catalyst complex in 99.75 wt. % to 98 wt. % of the vinyl siloxane polymer which usually has a zero-shear viscosity of from about 200 to 750 mPa.s. Solvents such as toluene and the like organic solvents have been used historically as alternatives but the use of vinyl siloxane polymers by far the preferred choice. These are described in US3,715,334 and US3,814,730. Alternatively, photo-activated hydrosilylation catalysts (vi) may be utilised. These may include but are not limited to platinum (II) β-diketonate complex catalysts such as Pt(II) bis(2,4-pentanedionate), Pt(II) bis(2,4-hexanedionate), Pt(II) bis(2,4-heptanedionate), Pt(II) bis(3,5-heptanedionate), Pt(II) bis(1-phenyl-1,3- butanedionate), Pt(II) bis(1,3-diphenyl-1,3-propanedionate), and the like; (η-diolefin) (σ- aryl)platinum complexes (η5-cyclopentadienyl)tri(σ-alkyl)platinum(IV) complexes and cyclopentadienylplatinum (IV) compounds, such as (methylcyclopentadienyl) trimethylplatinum (IV), and the complexes that derive therefrom; platinum(II) acetylacetonate (Pt(acac)2), as well as other known photo-activated hydrosilylation catalysts for catalysing curing reactions upon exposure to radiation such as ultraviolet (UV) radiation. In one preferred embodiment component (d) may be selected from co-ordination compounds of platinum. In one embodiment hexachloroplatinic acid and its conversion products with vinyl-containing siloxanes, Karstedt's catalysts and Speier catalysts are preferred.

[0058] The catalytic amount of the hydrosilylation catalyst is generally between 0.01 ppm, and 10,000 parts by weight of platinum-group metal, per million parts (ppm), based on the weight of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition; alternatively, between 0.1 and 7500ppm; alternatively between 0.1 and 1000 ppm, and alternatively between 1 and 100 ppm of metal based on the weight of the composition and wherein dependent on the form / concentration in which the catalyst is provided e.g., in a polymer or solvent, the amount of component (d) present will be within the range of from 0.001 to 3.0 wt. % of the composition, alternatively from 0.001 to 1.5 wt. % of the composition, alternatively from 0.01–1.5 wt. %, alternatively 0.01 to 1.0 wt. %, of the unscoured airbagfabric hydrosilylation curable silicone rubber coating composition. The catalysts may also be microencapsulated to increase shelf storage stability in 1 part or multi-part packages. (e) Adhesion promoter

[0059] Component (e), the adhesion promoter, is typically present in the composition in an amount of from about 0.1 to 6wt. % of the composition; alternatively, 0.1 to 4 wt. % of the composition.

[0060] As previously indicated component (e) is an organosiloxane adhesion promoter having the structure (e-1): Z2–[X - Si(CH3)2]u -O -Si (Ph)2 – O – [Si(CH3)2 – X]u – Z2Where each X is a linear or branched alkylene group having from 1 to 6 carbons, alternatively from 2 to 6 carbons, and alternatively from 2 to 4 carbons, Each Z2is a cyclic siloxane of the structure =(Si(R1) - O)-(Si(R1)(R2) -O)m- where each R1is an independently selected monovalent hydrocarbyl group, (alternatively an alkyl group) and each R2is independently selected from the group consisting of hydrogen (H) or an organic moiety comprising an epoxy group, m is from 3 to 20 alternatively an average value of from 3 to 16, alternatively an average value of from 3 to 13, alternatively an average value of from 3 to 11, alternatively an average value of from 3 to 7, alternatively an average value of from 3 to 5; and where each u is 0 or 1; and wherein each molecule contains a mixture of R2groups consisting of one or more organic moieties comprising an epoxy group and one or more hydrogens (H).

[0061] As will be seen from the structure above, each R2group is linked to a silicon which forms part of a siloxane ring and is not linked to a silicon in a linear chain. In the case when R2is H and consequently forms an Si-H bond, such a bond is sometimes referred to as a DHtype Si-H linkage.

[0062] Each R1is an independently selected monovalent hydrocarbyl group, independently selected from an aliphatic hydrocarbyl group, a substituted aliphatic hydrocarbyl group, an aromatic group or a substituted aromatic group with the term substituted having the same definition as provided previously. Each aliphatic hydrocarbyl group may be exemplified by, but not limited to, alkyl groups having from 1 to 20 carbons per group, alternatively 1 to 15 carbons per group, alternatively 1 to 12 carbons per group, alternatively 1 to 10 carbons per group, alternatively 1 to 6 carbons per group or cycloalkyl groups such as cyclohexyl. Specific examples of alkyl groups may include methyl, ethyl, propyl, pentyl, octyl, undecyl, and octadecyl groups, alternatively methyl and ethyl groups. Examples of aromatic groups or substituted aromatic groups are phenyl groups and substituted phenyl groups with substituted groups as described above.

[0063] Each R2is independently selected from the group consisting of hydrogen (H) or an organic moiety comprising an epoxy group. When an R2is an organic moiety comprising an epoxy group it may comprise an alkyl epoxide group or an alkyl glycidyl ether of the structures below: and branched or is different and isfrom 2 to 30, subscript t is from 2 to 15, alternatively, subscript t is from 2 to 10.

[0064] Each Component (e) molecule contains several R2groups. The actual number is dependent on the size of the siloxane rings but typically there is an average of six or more R2groups per molecule. As previously indicated, each molecule contains a mixture of R2groups consisting of one or more organic moieties comprising an epoxy group and one or more H groups.

[0065] Hence, given each molecule of component (e) contains a mixture of R2groups consisting of one or more organic moieties comprising an epoxy group and one or more H groups, (forming an Si-H bond with a silicon) such that the total number of R2groups in a molecule is Z where: Z = [total number of R2organic moieties comprising an epoxy group] + [total number of R2groups which are hydrogen (H) groups]

[0066] Hence, if Z = 6, i.e., a component (e) molecule contains six R2groups it may comprise any combination of the two types of groups i.e., one organic moiety comprising an epoxy group and five H groups and consequently five Si- H bonds, two organic moieties comprising an epoxy group and four H groups, or three organic moieties comprising an epoxy group and three H groups. In each of the above alternatives only organic moieties comprising an epoxy group and one or more H groups are present as R2groups.

[0067] In another alternative a maximum of six, alternatively a maximum of four, organic moieties comprising an epoxy group are present as a proportion of the R2groups per molecule of component (e). Alternatively, a maximum of three organic moieties comprising an epoxy group are present as a proportion of the R2groups per molecule of component (e). Alternatively, a maximum of two organic moieties comprising an epoxy group are present as a proportion of the R2groups per molecule of component (e).

[0068] In one embodiment, when each u is 0 in structure (e-1) shown above, component (e) may have the following structure (e-2): average value of from 2 to 19,each R1is an independently selected monovalent hydrocarbyl group, (alternatively an alkyl group) and each R2is independently selected from the group consisting of hydrogen (H) or an organic moiety comprising an epoxy group; and wherein each molecule contains a mixture of R2groups consisting of one or more organic moieties comprising an epoxy group and one or more hydrogens (H).

[0069] As indicated each subscript n independently has an average value of from 2 to 19, alternatively an average value of from 2 to 18, alternatively an average value of from 2 to 15, alternatively an average value of from 2 to 12, alternatively an average value of from 2 to 10, alternatively an average value of from 2 to 6, alternatively an average value of from 2 to 4.

[0070] In one preferred embodiment each siloxane ring in component (e) has one or two organic moieties comprising an epoxy group are present as a proportion of the R2groups per molecule of component (e), alternatively one organic moiety comprising an epoxy group is present per molecule of component (e). In each of the above the remaining R2groups are hydrogen (H). In the following structure it will be seen that there is one R2group which is an organic moiety per siloxane ring comprising an epoxy group and the remainder are hydrogen and each R1is a methyl group: O one skilled in thethis structure mayvary in that the number of siloxy units may be 4 (as shown) or more in each cyclic end group, and the exact positions of the silicon bonded hydrogen atoms and epoxy-functional groups on the silicon atoms in the cyclic end groups may vary.

[0071] Organosiloxane adhesion promoters suitable for use as component (e) may be prepared by various methods. For example, the organosiloxane of formula (e-2) may be prepared as follows. In a first method for preparing a reaction product comprising an organohydrogensiloxane, the method comprises the steps of: 1) combining, under conditions to effect dehydrogenative condensation reaction, starting materials comprising A) a Lewis acid catalyst comprising a fluorinated arylborane; B) diphenyl silane diol ofC) a cyclicsubscript v has an average value of 4 to 20; and each R1is an independently selected monovalent hydrocarbyl group as described above; thereby preparing the reaction product comprising the organohydrogensiloxane and a by-product comprising H2. The starting materials in step 1) may optionally further comprise D) a solvent.

[0072] The method for preparing the reaction product comprising the organohydrogensiloxane may optionally further comprise one or more additional steps. The method may further comprise: step 2) during and / or after step 1), removing the H2 generated during formation of the organohydrogensiloxane, and / or 3) neutralizing residual A) Lewis acid catalyst in the dehydrogenative condensation reaction product. By-product H2may be removed by any convenient means, such as stripping and / or burning. Neutralizing may be performed by adding E) a neutralizing agent to the dehydrogenative condensation reaction product and thereafter filtering the dehydrogenative condensation reaction product. Steps 2) and 3) may be performed in any order. If a particulate by-product is present, e.g., as a result of neutralization, the method may further comprise 4) removing a particulate such as alumina after neutralization by any convenient means, such as filtration. One skilled in the art would be able to select appropriate optional additional steps to recover the organohydrogensiloxane from the dehydrogenative condensation reaction product, if desired.

[0073] One or more of the method steps 1) to 4) described above may be performed at a temperature of 0 °C to 100 °C, alternatively 0 °C to 65 °C, alternatively 0 °C to 60 °C, alternatively 0 °C to 50 °C, alternatively 0 °C to 35 °C, alternatively 0 °C to 30 °C, and alternatively 0 to < 30 °C. Alternatively, step 1) may be performed at the temperature of 0 °C to 30 °C, alternatively 0 °C to < 30 °C, alternatively 0 °C to 25 °C, alternatively 0 °C to 20 °C, alternatively 0 °C to 15 °C, alternatively 0 °C to 10 °C, and alternatively < 30 °C. Without wishing to be bound by theory, it is thought that performing this method, particularly step 1), at relatively low temperatures (e.g., 30 °C or less, alternatively 25 °C or less, alternatively 20 °C or less, and alternatively 10 °C or less) may minimize or prevent deactivation of A) the Lewis acid catalyst.

[0074] The starting materials used in step 1) of the method for preparing the dehydrogenative condensation reaction product comprising the organohydrogensiloxane (alternatively the starting materials used in step 1) and any optional additional steps such as 2), 3), and 4) of this method) may be free of platinum group metal catalysts. The resulting dehydrogenative condensation reaction product, and the organohydrogensiloxane, may also be free of platinum group metal catalysts. “Free of” as used herein includes none, alternatively an amount non-detectable by inductively coupled plasma mass spectrometry (ICP-MS), and alternatively an amount insufficient to cause performance problems, of release coatings prepared from release coating compositions including the organohydrogensiloxane made by the method described herein. Without wishing to be bound by theory, it is thought that the absence of platinum group metal catalysts may also improve storage stability of the organohydrogensiloxane, as compared to an organohydrogensiloxane that contains the platinum group metal catalyst. Starting Material A) Lewis Acid Catalyst

[0075] Starting material A) in the method described herein is a Lewis acid catalyst comprising a fluorinated arylborane. The Lewis acid catalyst may be a trivalent boron compound with at least one perfluoroaryl group per molecule, alternatively 1 to 3 perfluoroaryl groups per molecule, alternatively 2 to 3 perfluoroaryl groups per molecule, and alternatively 3 perfluoroaryl groups per molecule. The perfluoroaryl groups may have6 to 12 carbon atoms, alternatively 6 to 10 carbon atoms, and alternatively 6 carbon atoms. Suitable Lewis acid catalysts are known in the art, for example, as disclosed in PCT Patent Application Publication WO2021 / 262940; U.S. Patent Application Publication 2023 / 0123215; U.S. Patent Application Publication 2023 / 0151156; and U.S. Patent Application Publication 2023 / 0151157. Alternatively, the Lewis Acid catalyst may be selected from the group consisting of (C5F4)(C6F5)2B; (C5F4)3B; (C6F5)BF2; BF(C6F5)2; B(C6F5)3; BCl2(C6F5); BCl(C6F5)2; (C6F5)B(OH)2; (C6F5)2BOH; (C6F5)2BH; (C6F5)BH2; (C7H11)B(C6F5)2; (C6F5)2B(OC2H5); or (C6F5)2B-CH2CH2Si(CH3). Alternatively, the Lewis acid catalyst may be selected from (C5F4)(C6F5)2B; (C5F4)3B; (C6F5)BF2; BF(C6F5)2; B(C6F5)3; BCl2(C6F5); BCl(C6F5)2; (C6F5)B(OH)2; (C6F5)2BOH; (C6F5)2BH; (C6F5)BH2; (C7H11)B(C6F5)2; (C6F5)2B(OC2H5); or (C6F5)2B-CH2CH2Si(CH3). Alternatively, the Lewis acid catalyst may comprise, or may be, tris(pentafluorophenyl)borane of formula B(C6F5)3. Such Lewis acid catalysts are commercially available from, e.g., Millipore Sigma of St. Louis, Missouri, USA. The amount of starting material A) will depend on the type and amount of other starting materials used, however, starting material A) may be present in an amount of 50 ppm to 6000 ppm based on combined weights of starting materials A), B) and C). Alternatively, the amount may be 50 ppm to 600 ppm on the same basis. Starting Material B) Diphenyl Silane Diol Compound

[0076] Starting material B) is diphenyl silane diol of formula B-1): Ph2Si(OH2) shown above. The diphenyl silane diol may be made by known methods, for example, as disclosed in U.S. Patent 3,398,179 to Flatt, and U.S. Patent 2,899,453 to Spector, et al. Diphenyl- silane diol (CAS #: 947-42-2) is commercially available from Gelest, Inc. of Morrisville, Pennsylvania, USA. Starting Material C) Cyclic Polyorganohydrogensiloxane

[0077] Starting material C) for the method described herein is a cyclic polyorganohydrogensiloxane of formula C-1): (R1HSiO2 / 2)v, where subscript v has an average value of 4 to 20, and each R1is an independently selected alkyl group. Alternatively, subscript v may have an average value of 4 to 10, alternatively 4 to 8, and alternatively 4 to 6. Alternatively, subscript v may have an average value of 4 to 6, alternatively 4 to 5, alternatively 5, and alternatively 4.5 to 5. In formula C-1), R1may be an alkyl group of 1 to 6 carbon atoms. Alternatively, R1may be selected from methyl, ethyl, or propyl. Alternatively, each R1may be methyl.

[0078] Examples of suitable cyclic polyorganohydrogensiloxanes for starting material C) include tetramethylcyclotetrasiloxane, pentamethylcyclopentasiloxane,hexamethylcyclohexasiloxane, and combinations of two or more thereof. Suitable cyclic polyorganohydrogensiloxanes are known in the art and are commercially available, e.g., from Dow Silicones Corporation of Midland, Michigan, USA.

[0079] The amounts of starting materials B) and C) depend on various factors including the OH content of B) the diphenyl silane diol and the silicon bonded hydrogen (SiH) content of C) the cyclic polyorganohydrogensiloxane. However, amounts are sufficient to provide a molar ratio of SiH in starting material C) to OH in starting material B) (SiH : OH ratio) of 10:1 to 40:1, alternatively 10:1 to 20:1, and alternatively 10:1 to 15:1. Starting Material D) Solvent

[0080] A solvent may be used in the method. The solvent may facilitate introduction of certain starting materials, such as starting material A) the Lewis acid catalyst. Solvents used herein are those that help fluidize the starting materials but essentially do not react with any of these starting materials. Solvent may be selected based on solubility the starting materials and volatility of the solvent. The solubility refers to the solvent being sufficient to dissolve and / or disperse the starting materials. Volatility refers to vapor pressure of the solvent.

[0081] Suitable solvents may be hydrocarbons. Suitable hydrocarbons include aromatic hydrocarbons such as benzene, toluene, or xylene; and / or aliphatic hydrocarbons such as heptane, hexane, or octane. Alternatively, the solvent may be a halogenated hydrocarbon such as dichloromethane, 1,1,1-trichloroethane or methylene chloride.

[0082] The amount of solvent can depend on various factors including the type of solvent selected and the amount and type of other starting materials selected. However, the amount of solvent may range from 0.1% to 99%, alternatively 2% to 50%, based on combined weights of starting materials A), B), and C). Starting Material E) Neutralizing agent

[0083] Starting material E) is neutralizing agent that may optionally be used to neutralize A) the Lewis acid catalyst after the dehydrogenative condensation reaction product forms. Alumina, triphenyl amine, triphenyl phosphine, and phenylacetylene are suitable neutralizing agents. Neutralizing agents are known in the art and are commercially available, e.g., from Millipore Sigma. The amount of neutralizing agent depends on various factors including the amount of starting material A), however, starting material E) may be present in an amount sufficient to provide a weight ratio of neutralizing agent to Lewis acid catalyst (E:A ratio) of 1:1 to 1000:1. Alternatively, when the neutralizing agent is triphenyl phosphine or phenylacetylene, the E:A ratio may be 1:1 to 20:1. Alternatively, when theneutralizing agent is alumina, the E:A ratio may be 100:1 to 1000:1. Suitable neutralizing agents such as those described above are commercially available from various sources including Millipore Sigma. Reaction Product of the Method

[0084] The dehydrogenative condensation reaction product of the method described above comprises a) the organohydrogensiloxane and the by-product comprising H2. The reaction product may further comprise unreacted starting materials, residual A) Lewis acid catalyst, and / or D) solvent, when used. The organohydrogensiloxane a) comprises formula a-1): , where each subscript n2), where subscript v has an average value of 4 to 20 as defined above), and R1is as described above. Alternatively, each subscript n independently may have an average value from 2 to 4, alternatively > 2 to 4, alternatively > 2 to 3, and alternatively 2.5 to 3, and alternatively 3.

[0085] The amounts of starting materials B) and C) may be used in amounts such that the molar ratio of cyclic polyorganohydrogensiloxane : diphenyl silanediol, C:B, is ≥ 4:1, alternatively > 6:1. Alternatively, starting materials B) and C) may be used in amounts such that the content of silicon bonded hydrogen atoms in starting material C) to content of silicon bonded hydroxyl groups in starting material B) (SiH : OH mole ratio) is 10:1 to 40:1, alternatively 10:1 to 20:1, and alternatively 10:1 to 15:1. Alternatively, SiH : OH ratio may be at least 8:1, at least 9:1, alternatively at least 12:1, alternatively at least 13:1, alternatively at least 14:1, alternatively at least 15:1, and alternatively at least 45:1; while at the same time, SiH : OH ratio may be up to 180 : 1, alternatively up to 90: 1. The organohydrogensiloxane is then used as an intermediate for further reaction to prepare the adhesion promoter described above as component (e), as follows.

[0086] The method described above may further comprise functionalizing the above described organohydrogensiloxane to form an epoxy-functional organosiloxane. Themethod for functionalizing the organohydrogensiloxane comprises: i) practicing the method comprising step 1), and optionally one or more of the additional steps, described above to prepare the reaction product comprising the organohydrogensiloxane, and ii) combining, under conditions to effect hydrosilylation reaction, starting materials comprising the dehydrogenative condensation reaction product described above, or a) the organohydrogensiloxane; b) a hydrosilylation reaction catalyst; and c) a reactive species having an average, per molecule at least one aliphatically unsaturated group capable of undergoing an addition reaction with a silicon bonded hydrogen atom of starting material a) the organohydrogensiloxane, wherein starting material c) further comprises one or more functional groups per molecule; thereby preparing a hydrosilylation reaction product.

[0087] Briefly stated, this method may be performed by modifying the method described in US Patent 9593209. Starting material a) the organohydrogensiloxane described hereinabove may be combined with the reactive species and the hydrosilylation reaction catalyst (described as components c) and d), respectively) in the amounts and under conditions described in US Patent 9,593,209 at col.8, line 44 to col.10, line 47. The hydrosilylation reaction may be carried out batchwise or continuous in any suitable equipment, such as a jacketed reactor with agitation means such as an impeller or baffles.

[0088] In the method described herein, the hydrosilylation reaction may be performed by optionally dissolving or dispersing b) the hydrosilylation reaction catalyst in d) a solvent (such as that described above as starting material D)) to facilitate mixing. Starting materials comprising a) the organohydrogensiloxane and c) the reactive species may be placed in the reactor with b) the hydrosilylation reaction catalyst, and the other of c) the reactive species and a) the organohydrogensiloxane may be fed into the reactor continuously or intermittently to control any exotherm. The reactor may be heated or cooled, such that the reaction mixture may be maintained a temperature of 50 ºC to 150 ºC, alternatively 60 ºC to 100 ºC, alternatively 70 ºC to 90 ºC.

[0089] Alternatively, the method for functionalizing the organohydrogensiloxane to form the epoxy-functional organosiloxane may optionally further comprise an additional step. For example, this method may further comprise iii) adding e) a hydrosilylation reaction inhibitor to the hydrosilylation reaction product; and / or iv) recovering the epoxy-functionalorganosiloxane from the hydrosilylation reaction product. Recovering may be performed by any convenient means, such as stripping and / or distillation with heating, and optionally under vacuum. Starting Material b) Hydrosilylation Reaction Catalyst

[0090] Hydrosilylation reaction catalysts suitable for starting material b) in the method for functionalizing the organohydrogensiloxane are known in the art and are commercially available. Hydrosilylation reaction catalysts include platinum group metal catalysts. Such hydrosilylation catalysts can be a metal selected from platinum, rhodium, ruthenium, palladium, osmium, and iridium. Alternatively, the hydrosilylation catalyst may be a compound of such a metal, for example, chloridotris(triphenylphosphane)rhodium(I) (Wilkinson’s Catalyst), a rhodium diphosphine chelate such as [1,2- bis(diphenylphosphino)ethane]dichlorodirhodium or [1,2- bis(diethylphospino)ethane]dichlorodirhodium, chloroplatinic acid (Speier’s Catalyst), chloroplatinic acid hexahydrate, platinum dichloride, and complexes of said compounds with low molecular weight organopolysiloxanes or platinum compounds microencapsulated in a matrix or coreshell type structure. Complexes of platinum with low molecular weight organopolysiloxanes include 1,3-diethenyl-1,1,3,3-tetramethyldisiloxane complexes with platinum (Karstedt’s Catalyst) and methylvinylcyclosiloxane complexes with platinum (Ashby’s Catalyst). These complexes may be microencapsulated in a resin matrix. Alternatively, a hydrosilylation catalyst may comprise 1,3-diethenyl-1,1,3,3- tetramethyldisiloxane complex with platinum. Exemplary hydrosilylation catalysts are described in U.S. Patent 12195593 and the references cited therein. The amount used may be sufficient to provide 1 ppm to 1,000 ppm of platinum group metal based on combined weights of starting materials a), b), and c). Starting Material c) reactive species

[0091] Starting material c) the reactive species described above for functionalizing the organohydrogensiloxane may comprise an organic compound, e.g., a reactive epoxy- functional species of formula: R6R7, where each R6is an aliphatically unsaturated group capable of undergoing an addition reaction, and each R7is the epoxy-functional group. Each R6may be independently selected from the group consisting of alkenyl (such as vinyl, allyl, and hexenyl) and alkynyl (such as propynyl or hexynyl). Alternatively, each R6may be vinyl. Alternatively, each R6may be allyl. Each R7is an organic moiety comprising an epoxy group. Examples of suitable compounds reactive species include allyl glycidyl ether, which is known in the art and are commercially available, e.g., from Millipore Sigma.

[0092] The amount of c) the reactive species depends on various factors including the desired degree of substitution of the organosiloxane. For example, the amount of reactive species may be sufficient to react all silicon bonded hydrogen atoms in a) the organosiloxane or an excess, e.g., a molar ratio of silicon bonded hydrogen atoms from a) the organohydrogensiloxane to aliphatically unsaturated groups from c) the reactive species (SiH:vinyl ratio) may be < 1:1 to 1:1. Alternatively, it may be desirable for the epoxy- functionalized organosiloxane to have both silicon bonded hydrogen atoms and functional groups derived from c) the reactive species. In this instance, SiH:Vi ratio may be > 1:1. Alternatively, starting materials a) and c) may be used in amounts such that an average of two silicon bonded hydrogen atoms per molecule are replaced with functional groups derived from c) the reactive species via the hydrosilylation reaction. e) Hydrosilylation Reaction Inhibitor

[0093] The hydrosilylation reaction inhibitor may be for example, an acetylenic alcohol such as methyl butynol or ethynyl cyclohexanol, a silylated acetylenic alcohol, an unsaturated hydrocarbon diester; a conjugated ene-yne, an olefinic siloxane, a maleate, a fumarate, or a combination thereof. The amount of inhibitor may be an amount effective to deactivate b) the hydrosilylation reaction catalyst, e.g., to prevent further reaction of the organosiloxane during recovery of the organosiloxane. The amount of inhibitor selected depends on various factors including the type and amount of catalyst and inhibitor selected, however, the amount may be 0.00001 to 3 parts by weight, per 100 parts by weight of c) the reactive species. Suitable hydrosilylation reaction inhibitors are known in the art and are described, for example, described as ingredient i) in US Patent 9593209 at col.15, line 35 to col.16, line 17.

[0094] The method described above produces a hydrosilylation reaction product comprising an epoxy- functionalized organopolysiloxane. The epoxy-functionalized organosiloxane comprises formula a’-1): R2the group consisting of H and an epoxy-functional group (which is derived from c) thereactive species via hydrosilylation reaction of R6, as described above), with the proviso that at least one R2per molecule is the epoxy-functional group (i.e., at least one instance of R2per molecule is not hydrogen). Alternatively, 1 to 4 instances of R2per molecule are epoxy-functional groups (i.e., other than hydrogen). Alternatively 1 to 3, alternatively 1 to 2, and alternatively an average of two instances of R2per molecule are the epoxy-functional groups. Alternatively, one instance of R2on each cyclic siloxane ring may be the epoxy- functional group and the other instances of R2may be H. The epoxy-functional group for R2is derived from starting material c) the reactive species described above. The epoxy- functional group for R2may be R6’R7, where R7is as described above, and R6’is a divalent hydrocarbon group produced via hydrosilylation reaction of the aliphatically unsaturated group of starting material c) the reactive species and a silicon bonded hydrogen atom of starting material a) the organohydrogensiloxane. Alternatively, in formula a’-1) each subscript n may independently have an average value of 2 to 4, alternatively > 2 to 4, alternatively 2 to 3, alternatively > 2 to 3, alternatively 2, and alternatively 3. The functionalized organosiloxane may be prepared as described in US Provisional Patent Application Serial No.63 / 592218, which is hereby incorporated by reference.

[0095] Alternatively, when in formula (e-1) above, each u = 1, then component (e), the adhesion promoter, can have the following structure (e-3): R1,to 4; there may be two R2epoxy-functional groups per molecule and the rest of the R2groups are hydrogen; each X may be an ethylene group (- (CH2)2 -) and each R1may be a methyl group. Alternatively, the epoxy-functional groups may be glycidoxypropyl groups. In formula (e-3), each R2is independently selected from the group consisting of H and an epoxy-functional group (which is derived from c) the reactive species via hydrosilylation reaction of R6, as described herein), with the proviso that at least one R2per molecule is theepoxy-functional group (i.e., at least one instance of R2per molecule is not hydrogen). Alternatively, 1 to 4 instances of R2per molecule are epoxy-functional groups (i.e., other than hydrogen). Alternatively 1 to 3, alternatively 1 to 2, and alternatively an average of two instances of R2per molecule are the epoxy-functional groups. Alternatively, one instance of R2on each cyclic siloxane ring may be the epoxy-functional group and the other instances of R2may be H. The epoxy-functional group for R2may be R6’R7, where R7is as described herein, and R6’is a divalent hydrocarbon group produced via hydrosilylation reaction of the aliphatically unsaturated group of starting material c) the reactive species and a silicon bonded hydrogen atom of starting material a) the organohydrogensiloxane. Alternatively, in formula a”-1) each subscript n may independently have an average value of 2 to 4, alternatively > 2 to 4, alternatively 2 to 3, alternatively > 2 to 3, alternatively 2, and alternatively 3. Alternatively, component (e) may comprise structure:, where one skilled in the art would recognize that this structure is illustrative and not limiting, and this structure may vary in that the number of siloxy units may be 4 (as shown) or more in each cyclic end group, and the exact positions of the silicon bonded hydrogen atoms and epoxy-functional groups on the silicon atoms in the cyclic end groups may vary.

[0096] The epoxy-functional organosiloxane of structure (e-3) shown above may be prepared by a hydrosilylation reaction method. For example, this method comprises preparing a first hydrosilylation reaction product comprising an organohydrogensiloxane, and a second hydrosilylation reaction product comprising the the epoxy-functional organosiloxane of formula (e-3). This method comprises the steps of: 1’) combining, under conditions to effect a first hydrosilylation reaction, starting materials comprising A’) an aliphatically unsaturated organosiloxane oligomer of formula CH3Ph CH3, wherein Ph represents phenyl, and each RViis anandC) the cyclic polyorganohydrogensiloxane of formula (R1HSiO2 / 2)v, where subscript v has the average value of 4 to 20; and each R1is an independently selected monovalent hydrocarbyl group as described and exemplified above; in the presence of b) a hydrosilylation reaction catalyst (as described and exemplified above); thereby preparing a reaction product comprising the organohydrogensiloxane. The starting materials used in step 1) may optionally further comprise an additional starting material selected from the group consisting of D) a solvent, e) a hydrosilylation reaction inhibitor, and F) a thiuram disulfide, and a combination thereof.

[0097] The first hydrosilylation reaction in step 1) may be carried out batchwise or continuous in any suitable equipment, such as a jacketed reactor with agitation means such as an impeller or baffles. Step 1) may be performed with mixing and heating, e.g., at a temperature of 50 °C to 100 °C, alternatively 60 °C to 90 °C, and alternatively 70 °C to 80 °C.

[0098] The method for preparing the first hydrosilylation reaction product comprising the organohydrogensiloxane may optionally further comprise one or more additional steps. For example, the method may optionally further comprise, before step 1’), treating (e.g., by stripping or distilling) one or more of the starting materials. For example, starting material A’) and / or starting material B) may be treated to remove water (drying) or other impurities before step 1’). Alternatively, the method may further comprise 2’) purifying the organohydrogensiloxane produced during step 1’). For example, after formation of the organohydrogensiloxane, purifying may be performed by any convenient means, such as stripping and / or distillation with heating and optionally reduced pressure. The method may optionally further comprise adding F) the thiuram disulfide compound. The thiuram disulfide compound may be added during step 1’). Alternatively, the thiuram disulfide compound may be added to the first hydrosilylation reaction product comprising the organohydrogensiloxane after step 1’) and / or to the organohydrogensiloxane after step 1’) or after step 2’), when step 2’) is present. The thiuram disulfide compound may optionally be delivered in a solvent, such as the solvent described above as starting material D).

[0099] Starting material A’) is the aliphatically unsaturated organosiloxane oligomer of , wherein Ph is phenyl, and each RViis an alkenylsuch as vinyl, allyl, or hexenyl. Alternatively, each RVimay be vinyl. Aliphatically unsaturated organosiloxane oligomerssuitable for use as starting material A’) are commercially available. For example 1,5- divinyl-3,3-diphenyl-1,1,5,5-tetramethyltrisiloxane with CAS #18586-22-6 is available from various sources, such as TCI America and Cymit Quimica S.L. of Barcelona, Spain. Starting material C) the cyclic polyorganohydrogensiloxane and, starting material b) the hydrosilylation reaction catalyst are as described and exemplified above.

[0100] An additional starting material may optionally be used in step 1’). The additional starting material may be selected from the group consisting of a solvent, which may be as described and exemplified above for starting material D), a hydrosilylation reaction inhibitor as described and exemplified above for starting material e), F) a thiuram disulfide compound, or a combination thereof. Starting Material F) Thiuram Disulfide Compound

[0101] Starting material F) is a thiuram disulfide compound (thiuram disulfide) The thiuram disulfide may have formula F-1): F-1), wherein RH, RN, RJ, and RKare eachhydrocarbon group having 1 to 20 carbon atoms, which may be saturated or unsaturated; a heteroatom-containing monovalent hydrocarbon group having 1 to 20 carbon atoms, which may be saturated or unsaturated; or combinations thereof. Suitable heteroatoms may include, for example, an oxygen atom. RHand RNgroups may combine to form one or more carbocyclic groups having 4 to 20 carbon atoms. RJand RKgroups may combine to form one or more carbocyclic groups having 4 to 20 carbon atoms.

[0102] RH, RN, RJ, and RKcan be the same or different, and alternatively, these groups may be the same. Alternatively RH, RN, RJ, and RKmay be each independently selected from an alkyl group having 1 to 20 carbon atoms, alternatively 1 to 12, alternatively 1 to 6, alternatively 1 to 4, or alternatively 1 to 2 carbon atoms; an aryl group having 6 to 20 carbon atoms, such as phenyl or benzyl; or combinations thereof. Alternatively, RH, RN, RJ, and RKare each independently selected from methyl, iso-butyl, n-butyl, or combinations thereof.

[0103] Specific examples of suitable thiuram disulfides include tetrabenzylthiuram disulfide (with CAS No.10591-85-2), tetramethylthiuram disulfide (with CAS No.137-26- 8), tetraethylthiuram disulfide (with CAS No.97-77-8), tetra(iso-propyl)thiuram disulfide, tetra(iso-butyl)thiuram disulfide (with CAS No.3064-73-1), and tetra(n-butyl)thiuramdisulfide (with CAS No.1634-02-2), all of which are commercially available from various sources such as Sigma-Aldrich, Inc., TCI America, Fischer Scientific, or Cymit Química S.L. Alternatively, the thiuram disulfide is selected from tetramethylthiuram disulfide, tetra(n-butyl)thiuram disulfide, or mixtures thereof.

[0104] The thiuram disulfide may be optionally diluted in a solvent before use in the method. The solvent may be any material that can dissolve the thiuram disulfide, as described and exemplified above for starting material D). Alternatively, the solvent for the thiuram disulfide may be selected from aromatic hydrocarbons such as benzene, halogenated hydrocarbons, ethers, or mixtures thereof. Without wishing to be bound by theory, it is thought that it may be desirable to use as little solvent as possible to facilitate dissolving the thiuram disulfide and, if desired, to later remove the solvent, e.g., by evaporation, distillation, and / or stripping. Examples of suitable solvents may include halogenated hydrocarbons such as dichloromethane, chloroform (CHCl3), and / or tetrachloromethane. The solvent may be used in an amount of 0.1% to 5% by weight based on the weight of the thiuram disulfide.

[0105] The thiuram disulfide compound may be added in an amount such that the molar ratio of the thiuram disulfide to platinum in the hydrosilylation reaction catalyst (F / Pt ratio) may range from 0.9 to 100. Alternatively, this molar ratio may be 1 or higher, alternatively greater than 1, alternatively 1.1 or higher, and alternatively 1.2 or higher, alternatively 2 or higher, alternatively 3 or higher, alternatively 4 or higher, alternatively 5 or higher, alternatively 6 or higher, alternatively 7 or higher, alternatively 8 or higher, alternatively 9 or higher; while at the same time this ratio may be 100 or lower, alternatively 75 or lower, alternatively 50 or lower, alternatively 40 or lower, alternatively 30 or lower, alternatively 20 or lower, alternatively 10 or lower, alternatively 5 or lower, alternatively 3 or lower, alternatively 2 or lower, and alternatively 1.2 or lower. Alternatively, this F / Pt ratio may be 1 to 10, alternatively 1 to 5, alternatively 2 to 5, alternatively 2 to 3.5, alternatively 1 to 2, and alternatively, 1 to 1.2. First Hydrosilylation Reaction Product of the Method

[0106] The first hydrosilylation reaction product prepared as described above comprises a”) an organohydrogensiloxane and the hydrosilylation reaction catalyst. The first hydrosilylation reaction product may further comprise the additional starting material, when used. The reaction product may also comprise an unreacted starting material, e.g., unreacted A’) or C), when a molar excess of A’) or C) is used.

[0107] The method may optionally further comprise one or more additional steps, such as purifying the organohydrogensiloxane after step 1’), e.g., by any convenient means such as stripping and / or distillation with heat and / or reduced pressure. Any unreacted startingmaterial A’) or C) and solvent, if used, may be recycled back to step 1’).

[0108] The a’) organohydrogensiloxane prepared as described above has formula (a”-1): R1,described organohydrogensiloxane to form an epoxy-functional organosiloxane. The method for functionalizing the organohydrogensiloxane is as described above and but replacing organohydrogensiloxane a) with organohydrogensiloxane a”). The method comprises: i) practicing the method comprising step 1’), and optionally an additional step, described above to prepare the reaction product comprising a”) the organohydrogensiloxane, and ii) combining, under conditions to effect hydrosilylation reaction, starting materials comprising the reaction product described above, or a”) the organohydrogensiloxane described above; optionally b) a hydrosilylation reaction catalyst; and c) the reactive species as described above.

[0110] Briefly stated, this method may be performed by modifying the method described in US Patent 9593209, as described and exemplified above. Starting material a”) the organohydrogensiloxane described hereinabove may be combined with the reactive species and the hydrosilylation reaction catalyst (described as components c) and d), respectively) in the amounts and under conditions described in US Patent 9593209 at col.8, line 44 to col.10, line 47. The hydrosilylation reaction may be carried out batchwise or continuous in any suitable equipment, such as a jacketed reactor with agitation means such as an impeller or baffles. The same reactor used to make a”) the organohydrogensiloxane may be used. Alternatively, a different reactor may be used. The resulting epoxy-functional organosiloxane prepared by this method has structure (e-3) above. Alternatively, the epoxy-functional organosiloxane with structure (e-3) described above may be prepared as described in US provisional Patent Application Number 63 / 663204 filed on 24 June 2024 and International Application Serial Number PCT / US25 / 24836 filed on 16 April 2025, both of which are hereby incorporated by reference, by varying appropriate starting materials. (f) A chelated metal condensation catalyst

[0111] Component (f) is any suitable chelated metal condensation catalyst, for example a metal acetylacetonate condensation catalyst, a metal alkylacetylacetonate condensation catalyst e.g., a metal ethylacetylacetonate condensation catalyst, a metal hexafluoroacetylacetonate condensation catalyst or a metal trifluoroacetylacetonate condensation catalyst. The metals in the above may be, selected from titanium, zirconium, aluminum, vanadium, chromium, scandium, manganese, iron, cobalt, nickel, copper and zinc. The structure of the acetylacetonate ion is (CH3C(=O)CHC(=O)CH−). It is commonly referred to in the industry as “acac”. Component (f) may be selected from acetyl acetonates (acacs) of the following transition metals namely zirconium (Zr(acac)4), aluminum (Al(acac)3), vanadium (VO(acac)2), chromium (Cr(acac)3), scandium (Sc(acac)3), manganese (Mn(acac)2), iron (Fe(acac)3), cobalt (Co(acac)3), copper ((Cu(acac)2) and zinc (Zn(acac)2.H2O) or any of their alkylacetylacetonate, e.g., ethylacetylacetonate, hexafluoroacetylacetonate or triflouroacetylacetonate equivalents.

[0112] In one embodiment chelated metal condensation catalyst is one of the above metal acac catalysts. Alternatively, component (f) is selected from Zr(acac)4, i.e., zirconium (IV) tetraacetyl acetonate or Al(acac)3, i.e., aluminium (III) triacetyl acetonate.

[0113] Typically, such a catalyst is introduced in an amount of from 0.05 - 2.0 wt.% of the composition, alternatively in an amount of from 0.05 – 1.75 wt.% of the composition, alternatively in an amount of from 0.075 – 1.5 wt.% of the composition alternatively in an amount of from 0.075 – 1.25 wt.% of the composition.

[0114] Optionally, in one embodiment, in addition to components (e) and (f) there is provided one or more tetra-alkoxy titanate(s) (referred to hereafter as component (g)). (g) one or more unchelated titanium containing condensation catalysts (Optional)

[0115] Component (g) is one or more unchelated titanium containing condensation catalysts, typically one or more tetra-alkoxy titanate(s). For the avoidance of doubt, such tetra-alkoxy titanates are sometimes respectively referred to as tetra-alkoxy titanium or as tetra-alkyl titanates.

[0116] Any suitable tetra-alkoxy titanates which act as condensation catalysts may be utilised. The tetra-alkoxy titanates may comprise compounds according to the generalformula Ti[OR7]4Where Ti is titanium and each R7may be the same or different and represents a monovalent, primary, secondary or tertiary aliphatic hydrocarbon group which may be linear or branched containing from 1 to 10 carbon atoms.

[0117] Typically, each R7may be the same or different and include but are not restricted to methyl, ethyl, propyl, isopropyl, n- butyl, isobutyl, tertiary butyl, tertiary amyl (C (C2H5) (CH3)2). pentyl or hexyl groups and branched secondary alkyl groups such as 2,4-dimethyl- 3-pentyl groups. In some embodiments one or more R7groups may contain partial unsaturation. In one embodiment all the R7are the same alkyl group.

[0118] Examples include the following titanates: Ti (OC(CH3)2)4 -tetraisopropyltitanate or tetraisopropoxy titanium (TiPT), Ti (OCH2CH(CH3)2)4 - tetraisobutyltitanate or tetraisobutoxy titanium (TiBT), Ti[OC(CH3)3]4– tetra tertiary butyl titanate or tetra tertiary butoxy titanium (TtBT) Ti (C (C2H5) (CH3)2)4 - tetratertiary amyl titanate Ti(OCH2CH2CH2CH3)4- tetra n-butyl titanate or tetra n-butoxy titanium (TnBT); and other suitable tetra-alkoxy titanate catalysts such as TyzorTM9000 commercially available from Dorf Ketal Specialty Catalysts, LLC which has has the formula Ti [isopropoxy]a’ [t-butoxy]b’, where the total number of [isopropoxy] + [tertiary butoxy] groups per Ti atom (a’ + b’) is 4 and wherein, on average there are about 10% [isopropoxy] and 90% [t-butoxy] groups. For the avoidance of doubt, the one or more tetra-alkoxy titanate(s) of component (g) are not partially or completely chelated.

[0119] Alternatively, the unchelated titanium containing condensation catalyst may be a titanium-based reaction product obtained or obtainable from a process comprising the steps of: (i) mixing a first ingredient, an alkoxy titanium compound having from 2 to 4 alkoxy groups with a second ingredient, a linear or branched polydiorganosiloxane polymer having at least two terminal silanol groups per molecule; (ii) enabling the first and second ingredients to react together by stirring under vacuum to form a reaction product; and (iii) collecting the reaction product of step (ii).

[0120] When present, component (g) herein is present in the composition in an amount of from 0.075 to 2.5 wt. % of the composition, alternatively 0.1 to 2.0 wt. % of the composition, alternatively from 0.1 to 1.75 wt.% of the composition.

[0121] Components (a) and (c) 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 and / or resin can be determined by Gel permeation chromatography (GPC) using polystyrene calibration standards. 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. The gel permeation chromatography may employ a triple detector system e.g., light-scattering detector, a refractive index detector, and / or a viscosity detector as well as polystyrene standards. Additional optional ingredients

[0122] Additional optional ingredients may be present in the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition as hereinbefore described depending on the intended final use thereof. Examples of such optional ingredients include cure inhibitors, silicone resins, pot life extenders, flame retardants, fire retardant fillers, pigments and / or colouring agents, bactericides, optional additional adhesion promoters (which are different from component (e)), wetting agents, heat stabilizers, compression set additives, plasticizers, and mixtures thereof.

[0123] When the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition as hereinbefore described is being cured via an addition / hydrosilylation reaction a cure inhibitor may be utilized to inhibit the cure of the composition. These cure inhibitors are utilized to prevent premature cure in storage and / or to obtain a longer working time or pot life of a hydrosilylation cured composition by retarding or suppressing the activity of the catalyst. Cure inhibitors of hydrosilylation catalysts (d), e.g., platinum metal-based catalysts are well known in the art and may include hydrazines, triazoles, phosphines, mercaptans, organic nitrogen compounds, acetylenic alcohols, silylated acetylenic alcohols, maleates, such as dibutyl maleate; fumarates, ethylenically or aromatically unsaturated amides, ethylenically unsaturated isocyanates, olefinic siloxanes, such as tetramethyltetravinylcyclotetrasiloxane; unsaturated hydrocarbon monoesters and diesters, conjugated ene-ynes, hydroperoxides, nitriles, and diaziridines. Alkenyl-substituted siloxanes as described in US 3,989,667 may be used, of which cyclic methylvinylsiloxanes are preferred.

[0124] One class of known cure inhibitors of hydrosilylation catalysts, e.g., platinum catalysts (d) include the acetylenic compounds disclosed in US 3,445,420. Acetylenic alcohols such as 2- methyl-3-butyn-2-ol constitute a preferred class of cure inhibitors that will suppress the activityof a platinum-containing catalyst at 25 ºC. Compositions containing these cure inhibitors typically require heating at temperature of 70 ºC or above to cure at a practical rate. Examples of acetylenic alcohols and their derivatives include 1-ethynyl-1-cyclohexanol (ETCH), 2-methyl-3-butyn-2-ol, 3-butyn-1-ol, 3-methyl butynol 3-butyn-2-ol, propargyl alcohol, 2-phenyl-2-propyn-1-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclopentanol, 1-phenyl- 2-propynol, 3-methyl-1-penten-4-yn-3-ol, and mixtures thereof. In one alternative the cure inhibitor is selected from one or more of 1-ethynyl-1-cyclohexanol (ETCH), tetramethyltetravinylcyclotetrasiloxane, 3-methyl butynol and / or dibutyl maleate.

[0125] When present, cure inhibitor concentrations as low as 1 mole of cure inhibitor per mole of the metal of catalyst (d) will in some instances impart satisfactory storage stability and cure rate. In other instances, cure inhibitor concentrations of up to 500 moles of cure inhibitor per mole of the metal of catalyst (d) are required. The optimum concentration for a given cure inhibitor in a given unscoured airbag fabric hydrosilylation curable silicone rubber coating composition herein is readily determined by routine experimentation. Mixtures of the above may also be used. Dependent on the concentration and form in which the cure inhibitor selected is provided / available commercially, when present in the composition, the cure inhibitor is typically present in an amount of from 0.0001-10wt. %, alternatively 0.001-5wt. %, cure inhibitor, alternatively 0.0125 to 5wt. % of the composition. Silicone Resins

[0126] The unscoured airbag fabric hydrosilylation curable silicone rubber coating composition may also include one or more silicone resins for example, silicone resins containing unsaturated groups selected from alkenyl groups, alkynyl groups or a mixture of alkenyl groups and alkynyl groups. Such silicone resins may be selected from T silicone resins (silsesquioxanes), DT silicone resins, MQ silicone resins, MDT silicone resins, MTQ silicone resins, QDT silicone resins or mixtures thereof. Such resins using the MDTQ notation comprise Q type (SiO4 / 2) siloxane units T type (R2 1SiO3 / 2) siloxane units; D type (R21SiO3 / 2) siloxane units and R2₃SiO1 / 2(M) siloxane units as indicated. Typically, the MQ resins when present, comprise SiO4 / 2 (Q) siloxane units and R2₃SiO1 / 2 (M) siloxane units wherein each R2may be the same or different and denotes a monovalent group selected from hydrocarbon groups, having from 1 to 20 carbon atoms and, alternatively from 1 to 12 carbon atoms. Examples of suitable R2groups include alkyl groups, such as methyl, ethyl, propyl, pentyl, octyl, undecyl and octadecyl; cycloaliphatic groups, such as cyclohexyl; alkenyl groups, having from 2 to 12 carbons, such as vinyl, propenyl, butenyl, pentenyl, hexenyl, and the like; alkynyl groups selected from ethynyl, propynyl, butynyl, pentynyl orhexynyl and the like; aryl groups such as phenyl, tolyl, xylyl, benzyl, alpha-methyl styryl and 2-phenylethyl; alternatively R2groups are vinyl, methyl, ethyl or phenyl groups, e.g., examples of preferred R2₃SiO1 / 2(M) siloxane units include Me₃SiO1 / 2, PhMe₂SiO1 / 2, ViMe₂SiO1 / 2 and Ph₂MeSiO1 / 2, where Me hereinafter denotes methyl, Vi is vinyl and Ph hereinafter denotes phenyl. T silicone resins may alternatively be referred to as silsesquioxanes. The silicone resin can be a single silicone resin or a mixture comprising two or more different silicone resins, each as described above. Typically, they are MQ resins comprising ViMe₂SiO1 / 2 in combination with Me₃SiO1 / 2, and / or PhMe₂SiO1 / 2 groups. Additionally, the silicone resin may be an MQ resin which may contain residual OZ5, where Z5can represent hydrogen or alkyl groups. O Z5groups remain on the Q components after synthesis of silicone MQ resins indicative of incomplete condensation during the reaction to produce the MQ resin providing the OZ content meets the above hydroxyl per mole Si requirements. Residual O Z5is inherent to the processes and reactions utilized to make MQ resins.

[0127] The silicone resin, when present, is typically delivered in a hydrocarbon or silicone solvent, free from solvent the silicone resin is typically a solid but preferably herein the silicone resin is delivered in a silicone solvent such as a non-functional polydimethylsiloxane or a polydimethylsiloxane comprising two or more alkenyl groups per molecule, such as for example component (a) herein.

[0128] For example, in an MQ resin, the molar ratio of M siloxane units to Q siloxane units has a value of from 0.5:1 to 1.2:1, alternatively 0.6:1 to 1.1:1, alternatively 0.8:1 to 1.1:1, alternatively 0.9:1 to 1.1:1. In one embodiment MQ resin includes a resinous portion wherein the M units are bonded to SiO4 / 2siloxane units (i.e., Q units) and each of Q units is bonded to at least one other SiO4 / 2 siloxane unit. The molar ratio of M units to Q units is from 0.3 : 1 to 1.2 : 1, alternatively 0.4:1 to 1.1:1, alternatively 0.5:1 to 1:1, alternatively 0.6:1 to 0.9:1. Such an MQ resin suitable may have a number-average molecular weight (Mn) of from 2000 to 50,000g / mol, alternatively from 3,000 to 30,000 g / mol. In one embodiment the silicone resin may be described in the terms of a molar fraction as an MQ silicone resin having the formula: (R43SiO1 / 2)u’(SiO4 / 2)v, wherein R4is a C1to C10hydrocarbon group free of aliphatic unsaturation, u’ is from 0.3 to 0.6, alternatively 0.37 to 0.52, v is from 0.4 to 0.7, alternatively 0.48 to 0.63, and the value of u + v is 1.0.

[0129] When present, in the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition the resin is in an amount of from 1 - 60wt. %, alternatively 1 - 40wt. %, and is preferably in the form of an MQ resin. Preferably, when component (b) isnot present, silicone resins as described above may be utilised to reinforce the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition. In such cases when (b) is absent and the silicone resin is present preferably the silicone resin comprises one or more unsaturated groups e.g., vinyl groups, alternatively the silicone resin is a vinylated MQ resin. Preferably component (b) or a silicone resin as described herein, or a mixture of component (b) and the silicone resin(s) is present in the composition.

[0130] Pot life extenders, such as triazole, may be used, but are not considered necessary in the scope of the present invention. The unscoured airbag fabric hydrosilylation curable silicone rubber coating composition may thus be free of pot life extender.

[0131] Examples of flame retardants chlorinated paraffins, hexabromocyclododecane, triphenyl phosphate, dimethyl methylphosphonate, tris(2,3-dibromopropyl) phosphate (brominated tris), and mixtures or derivatives thereof. When present in composition, if required the flame retardant may be present in an amount of from 5 to 50 wt. % of the composition.

[0132] Examples of fire-retardant fillers include aluminium oxide, calcium carbonate, hydromagnesite (Mg5(CO3)4(OH)2·4H2O), (Mg3Ca(CO3)4) or a mixture thereof, in particular a mixture of hydromagnesite and huntite, often referred to as HMH. Again, these fire-retardant fillers may be treated with a suitable hydrophobing agent as defined above to render them hydrophobic. Blends of hydromagnesite, and huntite are commercially available e.g., under the tradenames UltraCarbTM1251, UltraCarbTM1253, and UltraCarbTMLH3C from LKAB Minerals AB of Lulea, Sweden. Such filler blends comprise particles having particle sizes between from 0.5 to 15µm measured using Malvern Laser Diffraction (data sheets). It is understood that typically huntite particles have a particle size of around 1.0 µm or less, much smaller than the particle size of hydromagnesite particles. In one embodiment herein the hydromagnesite and huntite particles are treated with fatty acids e.g., stearic acid or fatty acid esters such as stearates to render them hydrophobic.

[0133] Examples of colouring agents for which may be utilized in the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition include pigments, vat dyes, reactive dyes, acid dyes, chrome dyes, disperse dyes, cationic dyes and mixtures thereof. The unscoured airbag fabric hydrosilylation curable silicone rubber coating composition as described herein may further comprise one or more pigments and / or colorants which may be added if desired. The pigments and / or colorants may be coloured, white, black, metal effect, and luminescent e.g., fluorescent and phosphorescent. Pigmentsare utilized to colour the composition as required. Any suitable pigment may be utilized providing it is compatible with the composition herein.

[0134] Suitable white pigments and / or colorants include titanium dioxide, zinc oxide, lead oxide, zinc sulfide, lithophone, zirconium oxide, and antimony oxide.

[0135] 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; lampblack, and metal effect pigments such as aluminium, copper, copper oxide, bronze, stainless steel, nickel, zinc, and brass.

[0136] 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.

[0137] 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 dyes may be used in form of pigment masterbatch composed of them dispersed in component (a) at the ratio of 25:75 to 70:30.

[0138] The unscoured airbag fabric hydrosilylation curable silicone rubber coating composition may be heat stabilised. Examples of heat stabilizers may include metal compounds such as red iron oxide, yellow iron oxide, ferric hydroxide, cerium oxide, cerium hydroxide, lanthanum oxide, copper phthalocyanine, fumed titanium dioxide, iron naphthenate, cerium naphthenate, cerium dimethylpolysilanolate and acetylacetone salts ofa metal chosen from copper, zinc, aluminum, iron, cerium, zirconium, titanium and the like. Other examples of heat stabilizers may include suitable antioxidants or metal scavengers such as salicyloylaminotriazole, 1,2-bis(3,5-di-tert-butyl-4- hydroxylhydrocinnamoyl)hydrazine, 2-Hydroxy-N-1H-1,2,4-triazol-3-ylbenzamide, and N’1,N’12-Bis(2-hydroxybenzoyl)dodecanedihydrazide. The amount of heat stabilizer when present in the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition may range from 0.01 to 1.0 % weight of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition. optional additional adhesion promoters (which are different from component (e))

[0139] The unscoured airbag fabric hydrosilylation curable silicone rubber coating composition may include one or more optional additional adhesion promoters (which are different from component (e)). These may include alkoxysilanes such as epoxyalkylalkoxysilanes, for example, 3-glycidoxypropyltrimethoxysilane and, mercapto- alkylalkoxysilanes, (trimethoxysillyl)ethane and (meth)acryloxy type adhesion promoters such as methacryloxypropyltrimethoxysilane and reaction products of ethylenediamine with silylacrylates. Isocyanurates containing silicon groups such as 1, 3, 5- tris(trialkoxysilylalkyl) isocyanurates may additionally be used as may short chain siloxane diols such as dimethyl methylvinyl siloxane diols, The adhesion promoter may be present in an amount of from 0.1 to 5.0 wt. % of the composition, alternatively from 0.1 to 3.5 wt. %

[0140] Hence the unscoured airbag fabric hydrosilylation curable silicone rubber coating compositions comprises: a) an organopolysiloxane polymer (a) having a zero-shear viscosity of from 100 to 200,000mPa.s inclusive at 25 ºC, alternatively from 1000 to150,000mPa.s at 25 ºC, alternatively, from 1000mPa.s to 125,000mPa.s, alternatively from 1000mPa.s to 70,000mPa.s at 25 ºC, having at least two unsaturated groups per molecule selected from alkenyl and / or alkynyl groups, in an amount of from 40 wt. % to about 80 wt. % of the composition, alternatively from 45 to 80 wt. % of the composition, alternatively from 50 to 80 wt. % of the composition of the composition; with the zero shear viscosity being measured in the manner described above. b) optionally one or more fillers selected from one or more reinforcing fillers, one or more non-reinforcing fillers, or a mixture thereof as hereinbefore described; said fillers (b) are typically treated to render them hydrophobic and are present in an amount of from 1.0 to 50wt. %. of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition, alternatively of from 1 to 30wt. %. of the composition,alternatively of from 2.5 to 30wt. %. of the composition, alternatively of from 3.5 to 25wt. %. of the composition; c) an organosilicon compound having at least two or at least three Si-H groups per molecule and which functions as a cross-linker; preferably the molar ratio of the silicon- bonded hydrogen atoms in component (c) to the total unsaturated groups selected from alkenyl and / or alkynyl groups in the composition is from 0.5:1 to 20:1, alternatively the molar ratio of silicon-bonded hydrogen atoms of component (c) to the total unsaturated groups selected from alkenyl and / or alkynyl groups in the organopolysiloxane (a) is preferably at least 1:1 and can be up to 8:1 or 10:1. Most preferably the molar ratio of Si-H groups to aliphatically unsaturated groups is in the range from 1.1:1 to 5:1; said organosilicon compound having at least two or at least three Si-H groups per molecule being present in an amount of from 0.1 to 10 wt. % of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition, alternatively 0.1 to 7.5wt. % of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition, alternatively 0.5 to 7.5wt. %, further alternatively from 0.5% to 5 wt. % of the composition. Component (c) functions as a cross-linker; (d) a hydrosilylation cure catalyst wherein the catalytic amount of the hydrosilylation catalyst is between 0.01 ppm, and 10,000 parts by weight of platinum-group metal, per million parts (ppm), based on the weight of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition; alternatively, between 0.1 and 7500ppm; alternatively between 0.1 and 1000 ppm, and alternatively between 1 and 100 ppm of metal based on the weight of the composition and wherein dependent on the form / concentration in which the catalyst is provided e.g., in a polymer or solvent, the amount of component (d) present will be within the range of from 0.001 to 3.0 wt. % of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition, alternatively from 0.001 to 1.5 wt. % of the composition, alternatively from 0.01–1.5 wt. %, alternatively 0.01 to 1.0 wt. %, of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition; (e) Adhesion promoter

[0141] Component (e) is an organosiloxane adhesion promoter having the structure: Z2–[X - Si(CH3)2]u -O -Si (Ph)2 – O – [Si(CH3)2 – X]u – Z2Where each X is a linear or branched alkylene group having from 1 to 6 carbons, alternatively 2 to 6 carbons; Each Z2is a cyclic siloxane of the structure =(Si(R1) - O)- (Si(R1)(R2) -O)m- where each R1is an independently selected monovalent hydrocarbyl group, (alternatively an alkyl group) and each R2is independently selected from the groupconsisting of hydrogen (H) or an organic moiety comprising an epoxy group, m is from 3 to 20 and where each u is 0 or 1; and wherein each molecule contains a mixture of R2groups consisting of one or more organic moieties comprising an epoxy group and one or more hydrogens (H); and is typically present in the composition in an amount of from about 0.1 to 6wt. % of the composition; alternatively, 0.1 to 4 wt. % of the composition; and (f) a chelated metal condensation catalyst

[0142] Component (f) is any suitable chelated metal condensation catalyst, for example a metal acetylacetonate condensation catalyst, a metal alkylacetylacetonate condensation catalyst e.g., a metal ethylacetylacetonate condensation catalyst, a metal hexafluoroacetylacetonate condensation catalyst or a metal triflouroacetylacetonate condensation catalyst. The metals in the above may be, selected from titanium, zirconium, aluminum, vanadium, chromium, scandium, manganese, iron, cobalt, nickel, copper and zinc. Typically, such a catalyst is introduced in an amount of from 0.05 - 2.0 wt.% of the composition, alternatively in an amount of from 0.05 – 1.75 wt.% of the composition, alternatively in an amount of from 0.075 – 1.5 wt.% of the composition alternatively in an amount of from 0.075 – 1.25 wt.% of the composition.

[0143] The composition may optionally comprise component (g) one or more tetra- alkoxy titanate(s) preferably when present comprise compounds according to the general formula: Ti[OR7]4 Where Ti is titanium and each R7may be the same or different and represents a monovalent, primary, secondary or tertiary aliphatic hydrocarbon group which may be linear or branched containing from 1 to 10 carbon atoms.

[0144] Typically, each R7may be the same or different and include but are not restricted to methyl, ethyl, propyl, isopropyl, n- butyl, isobutyl, tertiary butyl, tertiary amyl (C (C2H5) (CH3)2). pentyl or hexyl groups and branched secondary alkyl groups such as 2,4-dimethyl- 3-pentyl groups. In some embodiments one or more R7groups may contain partial unsaturation. In one embodiment all the R7are the same alkyl group; said one or more tetra- alkoxy titanate(s), (component (g)) herein are present in an amount of from 0.075 to 2.5 wt. % of the composition, alternatively 0.1 to 2.0 wt. % of the composition, alternatively from 0.1 to 1.75 wt.% of the composition.

[0145] Furthermore, the coated unscoured airbag fabric described herein is a unscoured airbag fabric coated with the cured product of the above unscoured airbag fabric hydrosilylation curable silicone rubber coating composition.

[0146] Typically, prior to use the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition is stored in two or more parts. Most commonly the compositionis stored in two parts, Part A and part B to keep components (c) the organosilicon compound having at least two or at least three Si-H groups per molecule which functions as a cross-linker (cross-linker) and (d) the hydrosilylation cure catalyst apart to avoid premature cure.

[0147] Typically, a Part A composition will comprise components: (a) polymer, (b) the one or more optional fillers as hereinbefore defined and (d) hydrosilylation cure catalyst and Part B will comprise: (a) polymer, (b) the one or more optional fillers as hereinbefore defined, (c) the organosilicon compound having at least two or at least three Si-H groups per molecule which functions as a cross-linker and Cure inhibitor when present.

[0148] Component (e) the adhesion promoter is typically stored in the part B composition because of the Si-H content therein. Component (f) the metal acetylacetonate condensation catalyst and when present component (g) the one or more tetra-alkoxy titanate(s) are stored in either or both Part A and part B provided it doesn’t react prematurely with any other ingredient stored in the respective part. Preferably it is present in the part A composition. If desired the composition may be stored prior to use in three or more parts.

[0149] Other additives when present in an unscoured airbag fabric hydrosilylation curable silicone rubber coating composition may be in either Part A or Part B, providing they do not negatively affect the properties of any other components present (e.g., catalyst inactivation).

[0150] Part A and part B of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition described herein are mixed together shortly prior to use to initiate cure of the full composition into a silicone elastomeric material. The Part A and part B compositions can be designed to be mixed in any suitable weight ratio e.g., part A : part B may be mixed together in weight ratios of from 100:1 to 1:100, alternatively from 10:1 to 1:10, alternatively from 5:1 to 1:5, but most preferred is a weight ratio of 1:1.

[0151] Ingredients in each of Part A and / or Part B may be mixed together individually or may be introduced into the composition in pre-prepared combinations for, e.g., ease of mixing the final composition. For example, components (a) and (b) are often mixed together to form an LSR polymer base or masterbatch prior to addition with other ingredients. Similarly, component (e) may also be premixed with component (a), if desired. These may then be mixed with the other ingredients of the Part being made directly or maybe used to make pre-prepared concentrates commonly referred to in the industry as masterbatches.

[0152] In this instance, for ease of mixing ingredients, one or more masterbatches may be utilized to successfully mix the ingredients to form Part A and / or Part B compositions. For example, a “fumed silica” masterbatch may be prepared. This is effectively an LSR silicone rubber base with silica treated in situ.

[0153] Parts A and B of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition may be prepared by combining all of their respective components at ambient temperature. Any mixing techniques and devices described in the prior art can be used for this purpose. The particular device to be used will be determined by the viscosities of components and the final composition. Suitable mixers include but are not limited to paddle type mixers e.g., planetary mixers and kneader type mixers. Cooling of components during mixing may be desirable to avoid premature curing of the composition.

[0154] Prior to use the respective Part A and Part B compositions are mixed together in the desired ratio.

[0155] As part of the method herein the coating composition as hereinbefore described may be applied on to a fabric substrate, typically a one-piece woven or flat fabric airbag substrate by any suitable known technique. These include spraying, gravure coating, bar coating, knife coating, e.g., coating by knife-over-roller, coating by knife-over-air; padding, dipping and screen-printing.

[0156] The unscoured airbag fabric hydrosilylation curable silicone rubber coating composition can be applied onto one or both sides of fabric material substrate, e.g., an airbag fabric which is to be cut into pieces and sewn to assemble an airbag or may be applied onto a one-piece woven airbag.

[0157] Curing of the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition herein applied onto the woven fabric is typically conducted by heating the composition at a temperature of from 150 to 200°C for 45 seconds to 2 minutes which can be accomplished using a suitable oven or through drying tunnel of circulating hot-air ovens.

[0158] Although it is not preferred, it is possible to apply the composition in multiple layers, which together have a pre-determined mean dry coat weight which can be measured in accordance with ISO 3801, It is also possible to apply onto the coating composition afurther compatible coating, e.g., of a material providing e.g., low friction, if deemed necessary.

[0159] Any suitable desired coat weight may be applied on the fabric material such as an airbag, e.g., from 15 to 150 g / m2, alternatively from 15 to 100 g / m2, alternatively from 20 to 75 g / m2determined in accordance with ISO 3801. The thickness of coating layer ranges from of 20 to 80μm depending on the coating weight. The unscoured airbag fabric substrate

[0160] The unscoured airbag fabric substrate onto which the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition is applied may be made from any suitable woven unscoured airbag fabric, particularly a plain weave unscoured airbag fabric, but can for example be a knitted or nonwoven unscoured airbag fabric. The unscoured airbag fabric may be made from synthetic fibres or blends of natural and synthetic fibres, for example polyamide fibres such as Nylon 6, Nylon 6,6 and Nylon 4,6; polyester fibers such as polyethylene terephthalate and polybutylene terephthalate; polyimide, polyethylene, polypropylene, polyester-cotton, polyacrylonitrile fiber fabric, aramid fiber fabric, polyether imide fiber fabric, polysulfone fiber fabric, carbon fiber fabric, rayon fiber fabric and / or glass fibres.

[0161] When treating an airbag of unscoured fabric, the airbag may be a one-piece woven airbag or may be flat fabric pieces which after coating are sewn together to provide sufficient mechanical strength. Such airbags are generally made from polyamide fiber fabric or polyester fiber fabric for applications requiring high strength, especially in the case of automotive one-piece woven airbags. Prior to coating with the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition described hereinthe woven fabric is preferably washed with water and dried.

[0162] For use as an airbag fabric, the fabric should be sufficiently flexible to be able to be folded into relatively small volumes, but also sufficiently strong to withstand deployment at high speed, e.g., under the influence of an explosive charge. Polyamide and polyester fibres are particularly preferred for making airbag fabrics; however, it can be difficult to get coatings to adhere to polyamide and polyester airbags, especially when unscoured, hence the need for adhesion promoters such as component (e) herein.

[0163] The airbag obtained by coating an unscoured airbag fabric with the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition described herein has at least one coating layer formed of a cured product from the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition described herein. If necessary,however, one or more additional layers may be provided on the coated woven fabric. Such additional layers are applied typically for improving the tactile sensation of the surface of a coated woven fabric, for improving abrasion resistance of the surface of a coated woven fabric, and / or for improving the strength of a coated woven fabric. The additional coating layer may be exemplified by a plastic film, a woven fabric, a non-woven fabric, or a coating layer formed of an elastic coating material other than the cured silicone rubber disclosed herein. Preferably no additional layers are required or desired.

[0164] This technology can be used in any suitable fabric application but is particularly suited for airbags applications particularly in the automobile market but also for e.g., escape chutes from aircraft. Examples

[0165] In the following examples, the compositions are defined in weight % (wt. %) unless otherwise stated. Table 0 – Starting Materials for Synthesis Examples Name Chemical Description Supplier C1) DOWSIL™ cyclic polymethylhydrogensiloxane mixture Dow Silicones s t h h h h

[0166] In this Synthesis Example 1, a 1L 3-neck flask was equipped with a condenser (air cooled) with a nitrogen sweep to a bubbler, a thermocouple, overhead stirring (glass rodwith teflon paddle) and a septum. The glassware was purged with nitrogen (3 L / min) for 20 minutes. MH-1109 (99.97 g) was then added to the flask followed by anhydrous toluene (49.97 g). Stirring was started (230 rpm) before addition of 0.324g of BCF catalyst solution (1% in toluene). Diphenyldisilanol (56.07g) was added in 4 portions over the course of ~1.5 hours maintaining the reaction temperature below 30 °C. The reaction mixture was stirred for an additional 1.5 hours after addition was complete. The resulting clear solution was then treated with 36 μL of phenyl acetylene before removal of volatiles via rotary evaporator (ramp to full vacuum, temperature ramp to 80 °C, held at 80 °C for ~1h). The resulting product was analyzed by LC-MS,1H NMR and29Si NMR and found to contain an organohydrogensiloxane comprising formula: each subscript nthe product.

[0167] In this Synthesis Example 2, a three-neck flask was charged with the product prepared in Synthesis Example 1 (85.2 g) and heated to 80 °C under N2 upon stirring. Karstedt’s catalyst (amount sufficient to provide 2 ppm of platinum) was added, followed by the gradual addition of allyl glycidyl ether (AGE) (24.8 g). The addition rate was controlled so that the reaction mixture temperature did not exceed 90 °C. After addition of AGE was complete, the reaction mixture was stirred at 80 °C under N2 for additional 1 hour before being cooled to room temperature. The resulting hydrosilylation reaction product was loaded with 1-ethynyl-1-cyclohexanol (0.17 g), stripped under vacuum, and characterized by1H,29Si, and13C NMRs and found to contain a functionalized organosiloxane comprising formulare two instances of R8ther moiety and the remaining instances of R8were each H, and each subscript n independently had an average value of 3 as the main component of the stripped product. This was used as adhesion promoter AP-1 in certain examples, below.

[0168] In this Synthesis Example 3, an organohydrogensiloxane was prepared as follows: 1) Set-up: 3000 ml 4-neck round bottom (RB) flask with dropping funnel, multiport with 2 inlets for dry N2(Drierite column) and dry air (Drierite column), temperature controller (attached to hot plate with over-temperature protection) and reflux condenser with cooling circulator attached. 2) Load toluene into the 3000 ml 4-neck RB flask together with 1% Pt (hexachloroplatinic acid : 6 H2O) in IPA solution. Target Pt-concentration <5 ppm. 3) Dry starting material B1) MViDPh2MViat the rotary evaporator at 115 °C, 0 mbar over 2-3 hours. 4) Load a mixture of starting material C2) stripped MH-1109 and starting material B1) MViDPh2MViin amounts to provide 1.5 Si-Vinyl / MH1109 ratio into the dropping funnel. 5) Open one port to introduce dry air into the RB flask (reactor) and to kick-off the hydrosilylation reaction and continue over the whole hydrosilylation reaction. 5) Start stirring and bring the reactor temperature up to 75 °C. Once a stable temperature is established start adding in the mixture dropwise from the dropping funnel. 6) Adjust the speed of addition to let the temperature increase to 77 – 80 °C to maintain a stable exothermic reaction. Occasional application of heat or removal of the heating mantle may be necessary to keep the reaction going or to keep the exotherm in check. 7) Once all mixture from the dropping funnel has been added to the reaction stir for ca 1 h at 75 °C, then take a sample and analyze to monitor the Si-Vinyl consumption with 1H NMR.8) Once completion of the reaction has been confirmed (all Vi consumed, check with 1H NMR) remove the heating block and let the reaction cool to 60 °C. 9) Add 1 wt% solution of n-Bu-thiuram in toluene at 60 °C (3.5:1 ratio with Pt). 10) Remove the heating block and stir for 3 hours without heating and let the reactor temperature drop to 24 °C. 11) Transfer the reaction mixture to a receiving flask. 12) Remove the volatiles by rotary evaporator at 95 °C at 0-1 mbar for 2 hours. 13) Transfer the product into a Nalgene bottle and keep under N2. Analyze by 1H, 13C and 29Si NMR.

[0169] The reaction scheme is exemplified below. One skilled in the art would recognize that the structure shown is exemplary and not limiting because MH-1109 can contain higher DP siloxanes in addition to tetramethylcyclotetrasiloxane, therefore, Organohydrogensiloxane 1 comprises a mixture of the structure shown with organohydrogensiloxanes having 5 and 6 siloxane units in each ring.ppm in Pt cat Pt cat tio l]Toluene in reaction Flask + Pt 400.000 461.41 4 0.8669 4.595 0.1838 0.234was functionalized as follows: A 4-neck round bottom flask was charged with Organohydrogensiloxane 1 prepared in Example 1 (94.09 g). The flask was equipped with a magnetic stir bar, a cooled condenser equipped with an outlet leading to a bubbler, a thermocouple fitted with a nitrogen inlet, and an addition funnel which was charged with allyl glycidyl ether (AGE, 121.32 g). Organohydrogensiloxane 1 was heated to 65-80 °C, followed by the addition of ca.2.8 g AGE upon stirring. Exotherm was observed immediately. AGE was added gradually at a rate to keep the reaction temperature below 95 °C. Karstedt’s catalyst (2 ppm Pt, 1 wt% solution in toluene) was added via micropipette once the exotherm began to stall. After addition of AGE was complete the reaction mixture was stirred at 80 °C for another 30 min. The SiH consumption was monitored by a Perkin Elmer FTIR fitted with an ATR plate. After cooled to ambient temperature, the reaction mixture was charged and mixed with 1-ethynyl-1-cyclohexanol (0.55 g, 0.17 wt%), before transferred to a Nalgene bottle. The product was stripped over three days in a vacuum chamber under 0 mmHg at ambient temperature, to remove excess AGE. The sample was analyzed by 1H, 13C and 29Si NMR as well as GPC, which confirmed that a partially substituted structure, having an average of one glycidoxypropyl group bonded to a silicon atom was present on each cyclic siloxane moiety. This glycidoxypropyl-functional organosiloxane is AP-2 used in certain examples, below.

[0171] In the examples below: Vinyl group and Si-H group content was measured by Infrared spectroscopy in accordance with ASTM E168 using standards of the carbon double bond stretch and silicon-hydrogen bond stretch respectively.

[0172] All viscosity measurements were taken at 25oC unless otherwise indicated.

[0173] All flex abrasion, or “scrub resistance” testing was carried out in accordance with ISO 5981:2007 test method A and the values provided in the Tables below are an average of three results in each case.

[0174] A series of compositions were prepared and were analyzed for their suitability as coatings for unscoured airbag fabrics. Whilst any suitable method can be used, unless the composition is to be used immediately it is prepared in two-parts, part A and part B with a view to preventing premature curing. The liquid silicone rubber compositions prepared were prepared as two-part compositions, part A and part B and the compositions used in the examples are provided in Tables 1a – 1c below. For these examples, the composition was kept in two-parts prior to use to ensure premature cure was avoided. To make the final compositions the parts A & B were intermixed before cure in a 1 : 1 weight ratio.

[0175] Two standard airbag coating compositions were prepared in each case initially two-part compositions were prepared a Part A and Part B compositions. These are all depicted in Table 1 below. Table 1: standard Part A and Part B compositions for two-part airbag coatings (wt. %) Ref.1 Part A Ref.1 Part Ref.2 Part Ref.2 Part B A B

[0176] In the above Table 1: Fumed Silica was CAB-O-SILTMMS-75D fumed silica which is commercially available from Cabot Corporation. Polymer 1 Vinyldimethylsiloxy terminated polydimethylsiloxane having a zero-shear viscosity of 40,000 mPa.s at 25 °C; Polymer 2 was Vinyldimethylsiloxy terminated polydimethylsiloxane having a zero-shear viscosity of 10,000 mPa.s at 25 °C.Adhesion Promoter 1 was glycidoxypropyltrimethoxysilane. Zirconium (iv) acac was zirconium(IV) acetylacetonate. Adhesion Promoter 2 was Dimethyl Methylvinyl siloxane Diol Cross-linker 1 is a trimethyl terminated dimethyl methylhydrogen siloxane having a degree of polymerization of 11 and 0.457% silicon bonded hydrogen (Si-H); Crosslinker 2: a trimethyl terminated dimethyl methylhydrogen siloxane having a degree of polymerization of 11 and 0.3% silicon bonded hydrogen (Si-H); and Polymer 3 was hydroxydimethylsiloxy terminated polydimethylsiloxane having viscosity of approximately 25 mPa.s at 25°C.

[0177] In a first step silicone rubber bases were prepared containing polymer 1 and when present polymer 2 and the fumed silica. The base composition was then split into two-parts and the other ingredients in the respective part were introduced to form the compositions depicted in Table 1 above. The resulting part A and part B compositions were then stored separately until shortly before use.

[0178] The Ref.1 airbag compositions when the Parts A & B depicted in Table 1 are mixed together in a 1 : 1 weight ratio and cured form a 10 Shore A (70 Shore 00) elastomer as defined in ASTM D2240-15. The Ref.2 airbag composition when the Parts A & B depicted in Table 1 are mixed together in a 1 : 1 weight ratio and cured form forms a 65 Shore 00 elastomer as defined in ASTM D2240-15.

[0179] In a first series of examples and comparative examples were prepared and compared with a reference example. In each case were appropriate the adhesion promoters identified in Table 2a were introduced into the Ref.1 part B composition or Ref.2 Part B Composition respectively thereby forming a modified Part B composition resulting therefrom. In such compositions the amounts used were measured in parts by weight per 100 parts by weight of the respective part B composition. Table 2a: Modified Ref.1 & 2 Part B Compositions with adhesion promoter in parts by weight per 100 parts by weight of the Ref.1 Part B Composition Ref.1 C.1 Ex.1 Ex.2 Ref.2 Ex.3

[0180] In the above, the comparative adhesion promoter 1 used had the following structure with n = average of about

[0181] AP- 1 was as described

[0182] And AP- 2 was as described above in Synthesis Example 4.

[0183] Cross-linker 3 was a commercially available cross-linker from Gelest Inc. sold under the HPM-502 tradename which is defined as an Si-H terminated methylhydrosiloxane-phenylmethylsiloxane co-polymer having a viscosity of between 75 and 110 cSt, and a 45-50 mol % of phenylmethylsiloxane (both values taken from supplier website).

[0184] The respective part A and part B compositions were then mixed in a 1 : 1 weight ratio to make an uncured airbag coating. The airbag coatings were coated onto flat unscoured polyethylene terephthalate (PET) fabric using a lab scale Mathis blade coater. Target coat weight was 60-70 g / m2. The resulting coated PET fabric was then cured for 90 seconds at 190 °C. The coated airbag fabric was then top coated with talc in a commercial topcoat sold under the tradename SILASTIC™ 3715 Topcoat which is a low-friction, low- soiling topcoat for cured liquid silicone rubber elastomers commercially available from Dow Silicones Corporation to meet the blocking requirements.

[0185] Once cured, flex abrasion testing (also referred to as scrub resistance) were measured in accordance with ISO 5981:2007( test method A) using both newly coated bags and bags after a period of aging (7 days at 95% relative humidity and 80 ℃). Samples of fabric were cut and loaded into the instrument and visually assessed for failure indicated by the presence of a pinholes and / or blistering. The values reported were the average value of the samples for three test results using the last successful scrub resistance measurement and the results are provided in Table 2b below. Table 2b: Scrub resistance results for Ref.1 & 2, Ex.1 to 3 and C.1 Initial Scrub resistance (Unscoured Aged Scrub resistance (UnscouredInitial Scrub resistance (Unscoured Aged Scrub resistance (Unscoured PET) PET) R f 2 400 400unmodified Part B composition. It was found that this reaches 1000 scrubs on unscoured PET initially but falls below the scrub resistance requirement (600) after aging. As a result, the Ref.1 coating has insufficient adhesion on unscoured fabric. Comparative C.1 incorporates a comparative adhesion promoter 1 a non-phenyl containing adhesion promoter into the modified part B composition. No improvement was seen in the scrub resistance performance. Ex.1 and Ex.2 use alternative phenyl functional adhesion promoters that contain at least two Si-H units and at least two epoxides. Both Ex.1 and Ex.2 meet the heat-and-humidity scrub requirement on unscoured PET.

[0187] Ref.2 is the second standard airbag coating composition depicted in Table 1. It has poor scrub performance before and after aging on unscoured PET. Incorporation of the commercial cross-linker HPM-502 in combination with an adhesion promoter AP-2 containing at least 2 epoxide groups, at least 1 phenyl group, and at least two Si-H groups (Ex.3) provide good initial and heat-and-humidity aged scrub performance.

[0188] A further set of examples was undertaken using the Ref.1 compositions depicted in Table 1. In Example 3 a titanium-based reaction product was used. The titanium-based reaction product was prepared using a Neulinger 50-liter compounder.

[0189] 19058 g of dimethylsilanol terminated polydimethylsiloxane having a viscosity of about 800 mPa.s at 25°C was first loaded into the compounder.76.232 g of tetraisopropoxy titanium was then added and the two components were thoroughly mixed in the compounder for 2 minutes at a low speed of from 5 to 20 rpm using a dissolver disk mixing element to induce high shear. A small amount of gel accumulated on the dissolver disk and was removed using a spatula. Subsequently, the resulting mixture was then mixed for another 2 minutes using a planetary mixing element designed for use in the compounder together with the dissolver disk mixing element. The speed of the planetary mixing element was gradually increased to a maximum of 50 revolutions per minute (rpm) and the speed of the dissolver mixing element was gradually increased to a maximum of 1300 rpm. Once the mixing elements had reached their respective maximum speed, a vacuum was applied and the temperature of the interior of the mixer was raised by shear mixing to about 90ºC. The reaction mixture was continuously mixed under dynamic vacuum for about 90 minutes,after which the reaction was deemed to have been completed. The resulting component (a) product was allowed to cool back to room temperature and viscosity of the product was measured using a modular compact rheometer type MCR 302 from Anton Paar GmbH of Graz, Austria with a 25mm diameter rational plate having a gap of 0.3mm at a shear rate of 1s- 1. The viscosity of the product was determined to be 23,275 mPa.s at 25°C.

[0190] C.2 to C.4 and Ex.3 were all prepared by preparing modified part A compositions (Table 3a) and / or modified part B compositions (Table 3b). Table 3a: Modified Ref.1 Part A Compositions containing with unchelated titanium containing condensation catalysts in parts by weight per 100 parts by weight of the Ref.1 Part A Composition C.2 C.3 C.4 Ex.3 Ref.1 Part A Composition 100 100 100 100 T. p p p y ght per 100 parts by weight of the Ref.1 Part B Composition C.2 C.3 C.4 Ex.3 Ref.1 Part B Composition 100 100 100 100

[0191] The respective part A and part B compositions were then mixed in a 1 : 1 weight ratio to make an uncured airbag coating. The airbag coatings were coated onto flat unscoured polyethylene terephthalate (PET) fabric using a lab scale Mathis blade coater. Target coat weight was 60-70 g / m2. Coated bags were cured for 90 s at 190 °C. Aged fabric was subjected to 7 days at 85% humidity and 85 ℃.

[0192] As previously indicated the flex abrasion, or “scrub resistance” testing was carried out as described above again in accordance with ISO 5981:2007 test method A. Samples of fabric were cut and loaded into the instrument and visually assessed for failure indicated by a pinhole or blistering. The results are depicted in Table 3c below with the values reported being last successful scrub. Table 3c: Scrub resistance results for C.2 to 4 and Ex.3 Initial Scrub resistance Aged Scrub ResistanceInitial Scrub resistance Aged Scrub Resistance (Unscoured PET) (Unscoured PET) E 3 1300 1000T) catalyst. Scrub performance for C.2 is virtually identical to Ref.1, demonstrating that the combination of chelated zirconium condensation catalyst and an unchelated titanium containing condensation catalysts alone without any additional adhesion promoter is insufficient for improved scrub performance.

[0194] C.3 contains comparative adhesion promoter 1 (shown above) which lacks the phenyl functionality. Scrub resistance performance for C.3 was poor compared to Ex.3 and comparable to Ref.1. C.4 contains the titanium reaction product and comparative adhesion promoter 1. This displayed poor scrub performance and demonstrated that in addition to containing epoxide and Si-H units, the multifunctional adhesion promoter should also contain phenyl units. The phenyl units help drive migration of the adhesion promoter to the interface where they are most effective.

Claims

CLAIMS 1. An unscoured airbag fabric hydrosilylation curable silicone rubber coating composition comprising: a) an organopolysiloxane polymer having a zero-shear viscosity of between 100 and 200,000mPa.s inclusive at 25 ºC, and at least two unsaturated groups per molecule, which unsaturated groups are selected from alkenyl groups, alkynyl groups or a mixture thereof; b) optionally one or more fillers; c) an organosilicon compound having at least two, or at least three Si-H groups per molecule; d) a hydrosilylation cure catalyst; e) an organosiloxane adhesion promoter having the structure: Z2–[X - Si(CH3)2]u-O -Si (Ph)2– O – [Si(CH3)2– X]u– Z2Where each X is a linear or branched alkylene group having from 1 to 6 carbons Each Z2is a cyclic siloxane of the structure =(Si(R1) - O)-(Si(R1)(R2) -O)m- where each R1is an independently selected monovalent hydrocarbyl group, (alternatively an alkyl group) and each R2is independently selected from the group consisting of hydrogen (H) or an organic moiety comprising an epoxy group, m is from 3 to 20 and where each u is 0 or 1; and wherein each molecule contains a mixture of R2groups consisting of one or more organic moieties comprising an epoxy group and one or more hydrogens (H); and f) a chelated metal condensation catalyst wherein the metal is selected from one or more of titanium, zirconium, aluminum, vanadium, chromium, scandium, manganese, iron, cobalt, nickel, copper and zinc.

2. An unscoured airbag fabric hydrosilylation curable silicone rubber coating composition in accordance with claim 1 wherein each u is 0 and component (e) has the following structure:of from 2 to 18,each R1is an independently selected monovalent hydrocarbyl group, and each R2is independently selected from the group consisting of hydrogen (H) or an organic moiety comprising an epoxy group; and wherein each molecule contains a mixture of R2groups consisting of one or more organic moieties comprising an epoxy group and one or more hydrogens (H).

3. An unscoured airbag fabric hydrosilylation curable silicone rubber coating composition in accordance with claim 2 wherein each subscript n independently has an average value of from 2 to 4, each R1is methyl, and each R2is independently selected from the group consisting of hydrogen and a glycidoxypropyl group; and wherein each molecule contains a mixture of R2groups consisting of one or more glycidoxypropyl groups and one or more hydrogens (H).

4. An unscoured airbag fabric hydrosilylation curable silicone rubber coating composition in accordance with claim 1 wherein u = 1 and adhesion promoter (e) has structure:selected divalent hydrocarbyl group with 2 to 6 carbons, each R1is an independently selected monovalent hydrocarbyl group, and each R2is independently selected from the group consisting of hydrogen and an organic moiety comprising an epoxy group; and wherein each molecule contains a mixture of R2groups consisting of one or more organic moieties comprising an epoxy group and one or more hydrogens (H).

5. An unscoured airbag fabric hydrosilylation curable silicone rubber coating composition in accordance with any one of claims 1, 2, 3 or 4 wherein component (e) is present in an amount of from about 0.1 to 6 wt. % of the composition; 6. An unscoured airbag fabric hydrosilylation curable silicone rubber coating composition in accordance with any one of claims 1, 2, 3, 4 or 5 wherein Component (f) isselected from Zr(acac)4, Al(acac)3, VO(acac)2, Cr(acac)3, Sc(acac)3, Mn(acac)2, Fe(acac)3, Co(acac)3, Cu(acac)2 and Zn(acac)2.H2O where acac stands for acetyl acetonate.

7. An unscoured airbag fabric hydrosilylation curable silicone rubber coating composition in accordance with any one of claims 6 wherein Component (f) is selected from zirconium (IV) tetraacetyl acetonate or aluminium (III) triacetyl acetonate.

8. An unscoured airbag fabric hydrosilylation curable silicone rubber coating composition in accordance with any one of claims 1, 2, 3, 4, 5, 6 or 7 wherein component (f) is present in the composition in an amount of from 0.05 - 2.0 wt.% of the composition.

9. An unscoured airbag fabric hydrosilylation curable silicone rubber coating composition in accordance with any one of claims 1, 2, 3, 4, 5, 6, 7 or 8 wherein the composition additionally comprises component (g) one or more unchelated titanium containing condensation catalysts.

10. An unscoured airbag fabric hydrosilylation curable silicone rubber coating composition in accordance with any claim 9 wherein component (g) is one or more tetra- alkoxy titanate(s).

11. An unscoured airbag fabric hydrosilylation curable silicone rubber coating composition in accordance with any one of claims 1 to 10 wherein component (c) comprises or consists of an Si-H terminated methylhydrosiloxane-phenylmethylsiloxane co-polymer having a zero-shear viscosity of from 50 to 300 cSt and 30 to 75 mol % of phenylmethylsiloxane units.

12. A coated unscoured airbag fabric comprising an unscoured airbag fabric coated with the cured product of an unscoured airbag fabric hydrosilylation curable silicone rubber coating composition in accordance with any one of claims 1 to 11.

13. A method of coating unscoured airbag fabric with an unscoured airbag fabric hydrosilylation curable silicone rubber coating composition in accordance with any one of claims 1 to 11 by applying the unscoured airbag fabric hydrosilylation curable silicone rubber coating composition onto an unscoured airbag fabric and curing the composition to form an unscoured airbag fabric.

14. A use of an organosiloxane adhesion promoter (e) having the structure: Z2–[X - Si(CH3)2]u -O -Si (Ph)2 – O – [Si(CH3)2 – X]u – Z2Where each X is a linear or branched alkylene group having from 1 to 6 carbons Each Z2is a cyclic siloxane of the structure =(Si(R1) - O)-(Si(R1)(R2) -O)m- where each R1is an independently selected monovalent hydrocarbyl group, (alternatively an alkyl group) andeach R2is independently selected from the group consisting of hydrogen (H) or an organic moiety comprising an epoxy group, m is from 3 to 20 and where each u is 0 or 1; and wherein each molecule contains a mixture of R2groups consisting of one or more organic moieties comprising an epoxy group and one or more hydrogens (H); and f) a chelated metal condensation catalyst wherein the metal is selected from one or more of titanium, zirconium, aluminum, vanadium, chromium, scandium, manganese, iron, cobalt, nickel, copper and zinc; in an unscoured airbag fabric hydrosilylation curable silicone rubber coating composition for coating an unscoured airbag fabric which composition otherwise comprises: a) an organopolysiloxane polymer having a zero-shear viscosity of between 100 and 200,000mPa.s inclusive at 25 ºC, and at least two unsaturated groups per molecule, which unsaturated groups are selected from alkenyl groups, alkynyl groups or a mixture thereof; b) optionally one or more fillers; c) an organosilicon compound having at least two or at least three Si-H groups per molecule; d) a hydrosilylation cure catalyst.

15. A use in accordance with claim 14 wherein components (a) to (f) are in accordance with any one of claims 2 to 11.

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