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WO2025081423A1 - Revêtements de silicone pour textiles et tissus - Google Patents

Revêtements de silicone pour textiles et tissus Download PDF

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Publication number
WO2025081423A1
WO2025081423A1 PCT/CN2023/125458 CN2023125458W WO2025081423A1 WO 2025081423 A1 WO2025081423 A1 WO 2025081423A1 CN 2023125458 W CN2023125458 W CN 2023125458W WO 2025081423 A1 WO2025081423 A1 WO 2025081423A1
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WO
WIPO (PCT)
Prior art keywords
curable silicone
silicone rubber
hydrosilylation curable
organosilicon
accordance
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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PCT/CN2023/125458
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English (en)
Inventor
Rui Wang
Dongchan Ahn
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Dow Silicones Corp
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Dow Silicones Corp
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Publication date
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Priority to PCT/CN2023/125458 priority Critical patent/WO2025081423A1/fr
Publication of WO2025081423A1 publication Critical patent/WO2025081423A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
    • D06N3/12—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins
    • D06N3/128—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins with silicon polymers
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
    • D06M15/19—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with synthetic macromolecular compounds
    • D06M15/37—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D06M15/643—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds containing silicon in the main chain
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C08G77/12—Polysiloxanes containing silicon bound to hydrogen
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C08G77/20—Polysiloxanes containing silicon bound to unsaturated aliphatic groups
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/70—Siloxanes defined by use of the MDTQ nomenclature

Definitions

  • This disclosure relates to hydrosilylation curable silicone rubber coating compositions for treating textiles and fabrics, to textiles and fabrics, such as inflatable safety restraint devices e.g., airbags coated with a cured product of the hydrosilylation curable silicone rubber coating compositions and to a process for coating said textiles and fabrics such as inflatable safety restraint devices e.g., airbags with the hydrosilylation curable silicone rubber coating composition.
  • inflatable safety restraint devices e.g., airbags coated with a cured product of the hydrosilylation curable silicone rubber coating compositions
  • a process for coating said textiles and fabrics such as inflatable safety restraint devices e.g., airbags with the hydrosilylation curable silicone rubber coating composition.
  • the hydrosilylation curable silicone rubber coating compositions have excellent flowability on the textiles surfaces and the textiles such as inflatable safety restraint devices e.g., airbags coated with a cured product of the hydrosilylation curable silicone rubber coating compositions herein are considered to have improved adhesion to woven fabrics and a lower total volatile organic compounds (TVOC) than seen with standard coating materials used to treat said textiles and fabrics.
  • inflatable safety restraint devices e.g., airbags coated with a cured product of the hydrosilylation curable silicone rubber coating compositions herein are considered to have improved adhesion to woven fabrics and a lower total volatile organic compounds (TVOC) than seen with standard coating materials used to treat said textiles and fabrics.
  • TVOC total volatile organic compounds
  • Textiles and fabrics are often treated with one or more coatings in order to provide them with a variety of properties.
  • Silicone coating compositions are used to provide textiles and/or fabrics with a wide variety of different properties.
  • One of the main applications for treated textiles and fabrics is for use in or as inflatable safety restraint devices, especially airbags.
  • Airbags are widely used to cushion vehicle occupants in the event of collisions and accidents.
  • Inflatable safety restraint devices such as airbags, generally consist of a textile or fabric bag (sometimes referred to as a cushion) , a sensor and a means of inflation.
  • airbags 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.
  • Airbags and/or airbag fabrics may be made from a woven or knitted fabric made of synthetic fibre, for example thermoplastics such as polyamides e.g., nylon-6, 6, or of polyester such as polyethylene terephthalate (PET) and benefit from the application of silicone coatings in a number of ways including:
  • softness and lightness of silicone coating provide airbags with very good flexibility, enabling them to be folded into a more compact module.
  • They 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.
  • Sewn flat fabric airbags are generally assembled with the coated fabric surface at the inside of the airbag.
  • One-piece woven airbags are coated on the outside of the airbag and are better able to retain gas pressure after deployment and therefore tend to be used for airbags designed to remain inflated for longer periods of time after a collision or the like, e.g., side-curtain airbags.
  • 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.
  • frontal airbags may be installed in the steering wheel on the driver′sside of car and in the dashboard on the passenger side of a car. They are provided to act 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.
  • these airbags are flat fabric pieces sewn together.
  • 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) .
  • 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.
  • One-piece woven type airbags are usually used for side-curtain airbags in combination with silicone sealant coatings in order to provide the low permeability (and thus longer gas escape times) necessary for side-curtain airbags.
  • 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 be 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.
  • 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.
  • adhesion promoters comprise a combination of alkoxysilanes, such as vinyltrialkoxysilanes,
  • organometallic catalyst such as tetra n-butyl titanate, (Ti (O (CH 2 ) 3 CH 3 ) 4 ) , tetraisopropyl titanate (Ti (OCH (CH 3 ) 2 ) 4 ) or zirconium acetyl acetonate (Zr (acac) 4
  • VOCs volatile organic compounds
  • methanol volatile siloxane species
  • the adhesion promoter catalyst the silanes and other ingredients of the composition e.g., siloxane polymers, oligomers, and or resins
  • the resulting VOCs are subsequently emitted as gases during and after the cure process.
  • the emission of VOCs in the automotive industry is a significant problem as hundreds of polymeric materials and parts are used, and a large proportion of these contain high levels of VOCs, which need to be identified and controlled before application.
  • VOC emission materials for use in car interiors in order to reduce total volatile organic compound (TVOC) emissions to meet automotive industry and OEMs requirements. Both have been driving for low emission materials for use in vehicle interiors having carbon emissions of less than ( ⁇ ) 50 ⁇ gC/g measured by GC-FID in accordance with industry testing requirements e.g., German Association of the Automotive Industry (VDA) test method VDA277 for volatile organic compounds.
  • VDA German Association of the Automotive Industry
  • VDA277 German Association of the Automotive Industry
  • the output of the measurement is referred to as “carbon emission” and ⁇ gC/g stands for means microgram Carbon per 1 gram sample.
  • hydrosilylation curable silicone rubber coating compositions for treating textiles and fabrics comprising:
  • an organopolysiloxane polymer having a viscosity of between 100 and 200,000mPa. s inclusive at 25 °C, and at least two unsaturated groups per molecule, which unsaturated groups are selected from alkenyl or alkynyl groups;
  • an organosilicon compound having at least two, alternatively at least three Si-H groups per molecule and which does not contain a bisphenyl unit;
  • an adhesion promoter comprising an organosilicon bisphenol adduct compound, comprising a bisphenyl unit which is not directly attached to a silicon atom, and at least one Si -H group, and optionally
  • one or more substantially non-functional organosilicon silicone resins selected from T silicone resins (silsesquioxanes) , DT silicone resins, MQ silicone resins, MDT silicone resins, MTQ silicone resins, QDT silicone resins or mixtures thereof.
  • coated textile material comprising a textile material coated with the cured product of a hydrosilylation curable silicone rubber coating composition
  • a hydrosilylation curable silicone rubber coating composition comprising:
  • an organopolysiloxane polymer having a viscosity of between 100 and 200,000mPa. s inclusive at 25 °C, and at least two unsaturated groups per molecule, which unsaturated groups are selected from alkenyl or alkynyl groups;
  • an organosilicon compound having at least two, alternatively at least three Si-H groups per molecule and which does not contain a bisphenyl unit;
  • an adhesion promoter comprising an organosilicon bisphenol adduct compound, comprising a bisphenyl unit which is not directly attached to a silicon atom, and at least one Si -H group, and optionally
  • one or more substantially non-functional organosilicon silicone resins selected from T silicone resins (silsesquioxanes) , DT silicone resins, MQ silicone resins, MDT silicone resins, MTQ silicone resins, QDT silicone resins or mixtures thereof.
  • hydrosilylation curable silicone rubber coating composition comprising the steps of mixing the components of the hydrosilylation curable silicone rubber coating composition:
  • an organopolysiloxane polymer having a viscosity of between 100 and 200,000mPa. s inclusive at 25 °C, and at least two unsaturated groups per molecule, which unsaturated groups are selected from alkenyl or alkynyl groups;
  • an organosilicon compound having at least two, alternatively at least three Si-H groups per molecule and which does not contain a bisphenyl unit;
  • an adhesion promoter comprising an organosilicon bisphenol adduct compound, comprising a bisphenyl unit which is not directly attached to a silicon atom, and at least one Si -H group; and optionally
  • one or more substantially non-functional organosilicon silicone resins selected from T silicone resins (silsesquioxanes) , DT silicone resins, MQ silicone resins, MDT silicone resins, MTQ silicone resins, QDT silicone resins or mixtures thereof;
  • hydrosilylation curable silicone rubber coating composition onto a textile surface and curing the composition to form a coated textile material.
  • an organosilicon bisphenol adduct compound comprising a bisphenyl unit which is not directly attached to a silicon atom, and at least one Si -H group; as an adhesion promoter in a hydrosilylation curable silicone rubber coating compositions for treating textiles and fabrics otherwise comprising:
  • an organopolysiloxane polymer having a viscosity of between 100 and 200,000mPa. s inclusive at 25 °C, and at least two unsaturated groups per molecule, which unsaturated groups are selected from alkenyl or alkynyl groups;
  • an organosilicon compound having at least two, alternatively at least three Si-H groups per molecule and which does not contain a bisphenyl unit;
  • one or more substantially non-functional organosilicon silicone resins selected from T silicone resins (silsesquioxanes) , DT silicone resins, MQ silicone resins, MDT silicone resins, MTQ silicone resins, QDT silicone resins or mixtures thereof.
  • composition described herein containing component (e) as the adhesion promoter shows very good flowability, mechanical strength, improved adhesion to woven fabrics and lower total volatile organic compounds (TVOC) versus traditional airbag coating LSR materials using organometallic catalyst and alkoxysilane as adhesion package.
  • a bisphenyl unit as described herein is intended to mean the following structure is present in the adhesion promoter:
  • the bisphenyl unit forms the backbone of the compound.
  • One or both aromatic rings may have at least one H replaced by another group and -X 2 -is a methylene bridge selected from
  • Component (a) of the hydrosilylation curable silicone rubber coating compositions for treating textiles and fabrics is one or more organopolysiloxane polymers having a viscosity of between 100 and 200,000mPa. s inclusive at 25 °C, and at least two unsaturated groups per molecule, which unsaturated groups are selected from alkenyl or alkynyl groups.
  • Each organopolysiloxane polymer of component (a) comprises multiple siloxy units, of formula (I) : R’ a SiO (4-a) /2 (I)
  • 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 organopolysiloxane polymer of component (a) is substantially linear but may contain a proportion of branching due to the presence of T units (as previously described) within the molecule, hence the average value of a in structure (I) is about 2.
  • 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.
  • 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.
  • 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.
  • each R’ 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.
  • 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.
  • 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.
  • aromatic groups or substituted aromatic groups are phenyl groups and substituted phenyl groups with substituted groups as described above.
  • 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 more carbons) providing each polymer has a viscosity of organopolysiloxane polymer (a) should be between 100 and 200,000mPa. s inclusive at 25 °C,
  • 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 dialkylalkenyl terminated methylvinyl methylphenyl dimethylsiloxane a trimethyl terminated methylvinyl
  • component (a) The viscosity of organopolysiloxane polymer (a) should be between 100 and 200,000mPa. s inclusive at 25 °C, alternatively from 1000 to 150,000mPa. s at 25 °C, alternatively, from 1000mPa. s to 125,000mPa. s, alternatively from 1000mPa. s to 100,000mPa. s at 25 °C.
  • the alkenyl and/or alkynyl content, e.g., vinyl content of the polymer is from 0.01 to 3 wt. %for each organopolysiloxane polymer containing at least two silicon-bonded alkenyl groups per molecule of component (a) , alternatively from 0.01 to 2.5 wt. %of component (a) , alternatively from 0.001 to 2.0 wt. %, alternatively from 0.01 to 1.5 wt. %of component (a) of the or each organopolysiloxane polymer containing at least two unsaturated groups per molecule, which unsaturated groups are selected from alkenyl or alkynyl groups per molecule of component (a) .
  • the alkenyl/alkynyl content of component (a) is determined using quantitative infra-red analysis in accordance with ASTM E168.
  • Component (a) may be present in the hydrosilylation curable silicone rubber coating composition in an amount of from 40 wt. %to about 80 wt. %of the hydrosilylation curable silicone rubber coating composition, alternatively from 45 to 80 wt. %of the composition, alternatively from 50 to 80 wt. %of the hydrosilylation curable silicone rubber coating composition.
  • 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.
  • Component (b) of the hydrosilylation curable silicone coating composition is an optional reinforcing filler comprising fumed silica, precipitated silica or a mixture thereof. Finely divided forms of silica are preferred. Reinforcing fillers (b) e.g., silica fillers having a relatively high surface area, typically at least 50 m 2 /g (BET method in accordance with ISO 9277: 2010) are utilized.
  • fillers e.g., fumed silica having surface areas of from 50-450m 2 /g, alternatively, 50 -400m 2 /g m 2 /g, alternatively from 50 to 300 m 2 /g, alternatively 100 -300m 2 /g (BET method in accordance with ISO 9277: 2010) are typically used.
  • the reinforcing filler (s) (b) 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 (b) do not clump and can be homogeneously incorporated into organopolysiloxane polymer (a) , described below, as the surface treatment makes the fillers easily wetted by organopolysiloxane polymer (a) .
  • the optional reinforcing filler (b) may be surface treated with any low molecular weight organosilicon compounds disclosed in the art applicable to prevent creping of organosiloxane compositions during processing.
  • organosilanes, polydiorganosiloxanes, or organosilazanes e.g., hexaalkyl disilazane, short chain siloxane diols or fatty acids or fatty acid esters such as stearates may be used to render the filler (s) hydrophobic and therefore easier to handle and obtain a homogeneous mixture with the other ingredients.
  • silanol terminated trifluoropropylmethyl siloxane examples 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, 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.
  • the optional reinforcing silica fillers (b) may be pre-treated prior to introduction into the hydrosilylation curable silicone coating composition or may be treated in situ (i.e., in the presence of at least a portion of the other ingredients of the hydrosilylation curable silicone coating composition herein by blending these ingredients together at room temperature or above until the filler is completely treated.
  • untreated reinforcing filler (b) 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.
  • the optional reinforcing filler (b) is present in the 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 5.0 to 25wt. %. of the composition.
  • Component (c) of the 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, alternatively at least three Si-H groups per molecule.
  • Component (c) is different from component (e) as it does not comprise any bisphenyl units.
  • Component (c) is typically linear, branched or a silicone resin.
  • Component (c) normally contains three or more silicon-bonded hydrogen atoms so that the 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.
  • Component (c) may alternatively have two silicon bonded hydrogen atoms per molecule.
  • 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.
  • component (c) partially comprises molecules having an average of two silicon bonded hydrogen atoms per molecule, said molecules may function as a chain extender.
  • the molecular configuration of the organosilicon compound having at least two, alternatively at least three Si-H groups per molecule (c) is not specifically restricted, and it can be a silane or a straight chain, branched (astraight chain with some branching through the presence of T units) or cyclic polymer or be silicone resin based.
  • component (c) While the molecular weight of component (c) is not specifically restricted, the viscosity may be measured using a Brookfield Cone/Plate viscometer, using spindle CP-52 at 12 rpm, based on ASTM D 4287. However, in the case of very low viscosities they may be measured using a glass capillary viscometer in accordance with ASTM D-445.
  • 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.
  • the silicon-bonded organic groups used in component (c) are alkyl groups, alternatively methyl, ethyl or propyl groups.
  • organosilicon compound having at least two, alternatively at least three Si-H groups per molecule include but are not limited to:
  • component (c) the cross-linker
  • 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.
  • the cross-linker (c) is generally present in the hydrosilylation curable silicone 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 hydrosilylation curable silicone rubber coating composition to increase when heated.
  • 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.
  • the silicon-bonded hydrogen (Si-H) content of component (c) is determined using quantitative infra-red analysis in accordance with ASTM E168.
  • the silicon-bonded hydrogen to alkenyl (vinyl) and/or alkynyl ratio is important when relying on a hydrosilylation cure process.
  • this is determined by calculating the total weight %of alkenyl groups in the 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] .
  • component (c) will be present in an amount of from 0.1 to 10 wt. %of the hydrosilylation curable silicone coating composition, alternatively 0.1 to 7.5 wt. %of the hydrosilylation curable silicone coating composition, alternatively 0.25 to 7.5wt. %, further alternatively from 0.25%to 5 wt. %of the hydrosilylation curable silicone coating composition, alternatively from 0.25%to 5 wt. %of the hydrosilylation curable silicone coating composition.
  • Component (d) of the hydrosilylation curable silicone 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, with platinum compounds most preferred.
  • 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.
  • 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.
  • 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) .
  • platinum based catalysts for example, platinum black, platinum oxide (Adams catalyst) , platinum on various solid supports, chloroplatin
  • Soluble platinum compounds that can be used include, for example, the platinum-olefin complexes of the formulae (PtCl 2 . (olefin) 2 and H (PtCl 3 . 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.
  • soluble platinum catalysts are, for the sake of example a platinum-cyclopropane complex of the formula (PtCl 2 C 3 H 6 ) 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-cyclopropane complex of the formula (PtCl 2 C 3 H 6 ) 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., (Ph 3 P) 2 PtCl 2 ; and complexes of platinum with vinylsiloxanes, such as sym-divinyltetramethyldisiloxane (Karstedt’s catalyst) .
  • suitable platinum-based catalysts of component (d) include
  • a platinum-containing catalyst which is obtained by a method comprising reacting chloroplatinic acid with an aliphatically unsaturated organosilicon compound, such as divinyltetramethyldisiloxane;
  • alkene-platinum-silyl complexes as described in US Pat. No. 6,605,734 such as (COD) Pt (SiMeCl 2 ) 2 where “COD” is 1, 5-cyclooctadiene; and/or
  • component (d) may be selected from co-ordination compounds of platinum.
  • hexachloroplatinic acid and its conversion products with vinyl-containing siloxanes, Karstedt′scatalysts and Speier catalysts are preferred.
  • 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 hydrosilylation curable silicone rubber coating composition; alternatively, between 0.1 and 7500ppm; alternatively, between 100 and 75000 ppm, and alternatively between 500 and 6,000 ppm.
  • the ranges may relate solely to the metal content within the catalyst or to the catalyst altogether (including its ligands) as specified, but typically these ranges relate solely to the metal content within the catalyst.
  • the catalyst may be added as a single species or as a mixture of two or more different species.
  • the amount of component (d) present will be within the range of from 0.001 to 3.0 wt. %of the 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 0.1.0 wt. %, of the hydrosilylation curable silicone coating composition.
  • Component (e) of the hydrosilylation curable silicone rubber coating composition is an adhesion promoter comprising an organosilicon bisphenol adduct compound, comprising a bisphenyl unit which is not directly attached to a silicon atom, and at least one Si -H group.
  • the organosilicon bisphenol adduct compound may comprise one or more straight-chain or cyclic optionally substituted organosiloxane moieties containing 1 to 50 silicon atoms, alternatively 1 to 30 silicon atoms, with at least one Si -H group. More than two aromatic rings may be present in the adhesion promoter if desired.
  • the adhesion promoter may be an organosilicon bisphenol adduct compound comprising one or more straight-chain or cyclic optionally substituted organosiloxane moieties containing 1 to 50 silicon atoms, alternatively 1 to 30, alternatively 2 to 20, and most preferably 3 to 10 silicon atoms. These organosiloxane moieties further contain at least one, preferably 1 to 20, and most preferably 2 to 10 Si-H groups.
  • these organosiloxane moieties may optionally comprise one or more additional functional groups such as, an alkoxy group, an epoxy group such as glycidoxy group, an alkoxysilyl group such as trimethoxysilyl group, triethoxysilyl group, and methyldimethoxysilyl group, an ester group, an acryl group, a methacryl group, a carboxy group, a carboxy anhydride group, isocyanate group, amino group, or amide group.
  • the adhesion promoter must contain the two aromatic groups of the bisphenyl unit but may contain 3, 4 or 5 aromatic groups.
  • the organosilicon bisphenol adduct compound may be an organosilicon bisphenol A adduct compound, an organosilicon bisphenol AP adduct compound, an organosilicon bisphenol AF adduct compound, an organosilicon bisphenol B adduct compound, an organosilicon bisphenol BP adduct compound, an organosilicon bisphenol C adduct compound, an organosilicon bisphenol E adduct compound, an organosilicon bisphenol F adduct compound an organosilicon bisphenol G adduct compound, an organosilicon bisphenol M adduct compound, an organosilicon bisphenol P adduct compound or an organosilicon bisphenol Z adduct compound.
  • the organosilicon bisphenol adduct compound is an organosilicon bisphenol A adduct compound.
  • a bisphenyl unit as described herein is intended to mean the following structure is present in the adhesion promoter:
  • the bisphenyl unit forms the backbone of the compound.
  • One or both aromatic rings may have at least one H replaced by another group and -X 2 -may be selected from a methylene bridge selected from -C (CH 3 ) 2 -, -C (Ph) (CH 3 ) -, -C (Ph) 2 , -C (CF 3 ) 2 -, -C (CH 3 ) (C 2 H 5 ) -, -C (CH 2 ) 5 --C (CH 3 ) (H) -, or -C (H) 2 -, where Ph is a phenyl -.
  • the -X 2 -methylene bridge is -C (CH 3 ) 2 -,
  • an example of the adhesion promoter may be the reaction product of bisphenol A bisallyl ether (i.e., with the -X 2 -methylene bridge being -C (CH 3 ) 2 -) , of the structure
  • d is integer of from 2 to 7, alternatively where d is 3 or 4) .
  • examples of the organosilicon bisphenol adduct compound adhesion promoter may have the following structure: -
  • Z 3 is an alkylene group having from 2 to 6 carbons, alternatively 2 to 5 carbons, alternatively 2 to 4 carbons, alternatively is an ethylene or propylene group;
  • R 15 is a cyclic siloxane of the structure - (CH 3 ) SiO- (R 14 H SiO) d ;
  • R 16 is a cyclic siloxane of the structure (OSiR 14 H) d -OSi (CH 3 ) -;
  • R 14 is an alkyl group having from 1 to 6 carbons and
  • d is integer of from 2 to 7.
  • it may comprise oligomers thereof.
  • n is an integer from 1 to 5.
  • R 20 is an epoxide group
  • Z 4 is an alkylene group having from 2 to 6 carbons
  • R 18 , X 2 , Z 3 and R 15 are all as defined above;
  • Y 2 is a cyclic siloxane of the structure - (CH 3 ) SiO- (R 17 H SiO) e -OSi (CH 3 ) -
  • the adhesion promoter provides a strong bonding performance between the resulting coating and the fabric substrate, including woven fabrics.
  • Adhesion promoter (e) is typically present in the hydrosilylation curable silicone rubber coating composition in an amount of from about 0.3 to 10wt. %of the composition, alternatively from 1.0 to 7.5 wt. %of the composition, alternatively from 1.0 to 5 wt. %of the composition.
  • adhesion promoter comprising the reaction product of at least one or more alkoxysilanes, in combination with an organometallic catalyst, in particular titanates and/or zirconates
  • adhesion promoter (e) herein resulted in excellent adhesion results but also result in significantly less VOCs being emitted both during the curing process but advantageously also after the completion of the cure process.
  • the results obtained enabled the requirements for carbon emissions of less than ( ⁇ ) 50 ⁇ gC/g measured by GC-FID in accordance with VDA test method VDA277 for volatile organic compounds to be met despite concerted efforts within the industry.
  • Selective adhesion is not suitable for in the case of airbag coatings as the adhesion between coating and substrate must remain fully intact, potentially for the lifetime of a vehicle or be able to immediately inflate upon detection of an impact in a vehicle collision or other accident.
  • Selective adhesion of silicone rubbers to pre-molded thermoplastic substrates via injection molding requires significantly different compositions to be used.
  • the pre-molded substrates include polycarbonate (PC) , polyamide (PA66) , polybutylene terephthalate (PBT) and such silicone selective adhesion compositions are able to promote the adhesion of LSR to thermoplastics using an injection molding process and such compositions are very different from textiles and fabric substrates used for airbags.
  • the pre-molded substrates are actually very different from woven fabric.
  • the surface statue determines the interaction of the and substrate, that impacts on adhesion significantly. We didn’t simply conclude that it works for thermoplastics, so it also works for coatings for textiles and fabrics.
  • Airbag coatings require far more than simply adhesion to the fabric because the ultimate goal is that they are able to stabilize the fabric against premature pressure loss upon deployment and enable the airbag to deploy, inflate and protect the occupants within the milliseconds of the initial impact in a collision. Hence the integrity of an airbag coating is paramount when utilising a new ingredient as important as an adhesion promoter in an airbag composition and must be satisfactory.
  • airbag coatings need to successfully pass tests such as scrub tests which far more than solely adhesion, as it’s effectively a tribological test -a test of sliding friction.
  • the amount of stress that gets transferred to the interface where adhesion promoters are thought to interact chemically with the fabric depends on the thickness, uniformity of coating, frictional properties, and bulk viscoelastic properties of the coating.
  • compositions used to coat textiles and fabrics especially airbag fabrics which contain component (e) herein can be used as adhesion promoter to replace traditional adhesion promotion systems comprising an organometallic, typically zirconium-based catalysts and alkoxysilane for airbag coating.
  • the coated fabrics with such airbag coatings applied provide improved TVOC performance and will not contain an active or partially active condensation catalyst in the resulting cured product.
  • the optional one or more silicone resins of component (f) in the hydrosilylation curable silicone coating composition are silicone resins containing unsaturated groups selected from alkenyl groups, alkynyl groups or a mixture of alkenyl groups and alkynyl groups, 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 of component (f) using the MDTQ notation comprise Q type (SiO 4/2 ) siloxane units T type (R 2 1 SiO 3/2 ) siloxane units; D type (R 2 1 SiO 3/2 ) siloxane units and R 2 3 SiO 1/2 (M) siloxane units as indicated.
  • These resins can be classified into two broad categories: silsesquioxanes and silicates. Silsesquioxanes, or T resins, are predominantly comprised of T units and can be synthesized by the hydrolysis and condensation of alkoxysilanes, chlorosilanes, or mixtures thereof.
  • Silicates, or MQ resins are predominantly comprised of M and Q units and can be synthesized through the hydrolysis and condensation of alkoxysilanes and chlorosilanes.
  • MQ resins can be synthesized through the polymerization of aqueous alkali silicates in the presence of acid followed by reaction with triorgano alkoxysilanes, triorgano chlorosilanes, hexaorganodisiloxanes or mixtures thereof.
  • component (f) is one or more MQ resins.
  • the MQ resins of component (f) when present, comprise SiO 4/2 (Q) siloxane units and R 2 3 SiO 1/2 (M) siloxane units wherein each R 2 may 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.
  • R 2 groups 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 or hexynyl and the like; aryl groups such as phenyl, tolyl, xylyl, benzyl, alpha-methyl styryl and 2-phenylethyl; alternatively R 2 groups are vinyl, methyl, ethyl or phenyl groups, e.g., examples of preferred R 2 3 SiO 1/2 (M) siloxane units include Me 3
  • 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 ViMe 2 SiO 1/2
  • the silicone resin is an MQ resin which may contain residual OZ 5 , where Z 5 can represent hydrogen or alkyl groups.
  • O Z 5 groups 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 Z 5 is inherent to the processes and reactions utilized to make MQ resins. The MQ resin may also undergo a subsequent silylation reaction to further minimize residual O Z 5 .
  • the silicone resin (f) 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 (f) 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.
  • 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.
  • MQ resin (e) includes a resinous portion wherein the M units are bonded to SiO 4/2 siloxane units (i.e., Q units) and each of Q units is bonded to at least one other SiO 4/2 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 as component (f) may have a number-average molecular weight (Mn) of from 2000 to 50,000g/mol, alternatively from 3,000 to 30,000 g/mol.
  • the silicone resin may be described in the terms of a molar fraction as an MQ silicone resin having the formula: (R 4 3 SiO 1/2 ) u (SiO 4/2 ) v
  • R 4 is a C 1 to C 10 hydrocarbon 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
  • the value of u + v is 1.0.
  • silicone resins are well known in the art. For example, they may be made by treating a resin copolymer produced by a silica hydrosol capping process with an alkyl and/or alkenyl containing end-blocking agent. This preferably includes reacting a silica hydrosol under acidic conditions with a hydrolysable triorganosilane such as trimethylchlorosilane, a siloxane such as hexamethyldisiloxane, and combinations thereof, and then recovering a copolymer having M (R 3 SiO 1/2 ) units and Q (SiO 4/2 ) units including 0.07 to 0.2 moles hydroxyl per mole of silicon (Si) .
  • a hydrolysable triorganosilane such as trimethylchlorosilane
  • a siloxane such as hexamethyldisiloxane
  • the copolymer may be further reacted with an end-blocking agent including saturated organic groups to achieve the less than 0.06 moles hydroxyl per mole Si.
  • Suitable end-blocking agents include silazanes, siloxanes, silanes, and combinations thereof.
  • the silicone resin (f) 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 (f) 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.
  • 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.
  • any suitable MQ resin may be utilized as component (f) .
  • 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.
  • MQ resin (f) includes a resinous portion wherein the M units are bonded to SiO 4/2 siloxane units (i.e., Q units) and each of Q units is bonded to at least one other SiO 4/2 siloxane unit.
  • the molar ratio of M units to Q units is 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.
  • Such an MQ resin suitable as component (f) may have a number-average molecular weight (Mn) of from 2000 to 50,000g/mol, alternatively from 3,000 to 30,000 g/mol.
  • component (f) may be present in the hydrosilylation curable silicone rubber coating composition in an amount of from 1-60wt. %, alternatively 1-40wt. %, and is preferably in the form of an MQ resin.
  • silicone resins are well known in the art. For example, they may be made by treating a resin copolymer produced by a silica hydrosol capping process with an alkyl and/or alkenyl containing end-blocking agent.
  • This preferably includes reacting a silica hydrosol under acidic conditions with a hydrolysable triorganosilane such as trimethylchlorosilane, a siloxane such as hexamethyldisiloxane, and combinations thereof, and then recovering a copolymer having M (R 3 SiO 1/2 ) units and Q (SiO 4/2 ) units including 0.07 to 0.2 moles hydroxyl per mole of silicon (Si) .
  • the copolymer may be further reacted with an end-blocking agent including saturated organic groups to achieve the less than 0.06 moles hydroxyl per mole Si.
  • Suitable end-blocking agents include silazanes, siloxanes, silanes, and combinations thereof.
  • Components (a) , (c) , and (f) invariably consist of a mixture of macromolecular species with different degrees of polymerization and therefore of different molecular weights.
  • 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 DP is linked to the viscosity of the polymer via Mw, the higher the DP, the higher the viscosity.
  • the silicone resin typically has a weight-average molecular weight (M w ) of from 2,000 to 50,000 Daltons, alternatively from 3,000 to 40,000, alternatively from 3,000 to 30,000, alternatively from 4,000 to 30,000, alternatively 5,000 to 25,000 where the molecular weight is determined by gel permeation chromatography employing a triple detector system e.g., light-scattering detector, a refractive index detector, and/or a viscosity detector and polystyrene standards.
  • M w weight-average molecular weight
  • Additional optional ingredients may be present in the hydrosilylation curable silicone rubber coating composition as hereinbefore described depending on the intended final use thereof.
  • optional ingredients include cure inhibitors, pot life extenders, flame retardants, lubricants, non-reinforcing fillers, pigments and/or colouring agents, bactericides, wetting agents, heat stabilizers, compression set additives, plasticizers, and mixtures thereof.
  • an inhibitor may be utilized to inhibit the cure of the composition. These 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.
  • 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.
  • One class of known inhibitors of hydrosilylation catalysts 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 inhibitors that will suppress the activity of a platinum-containing catalyst at 25 °C.
  • Compositions containing these inhibitors typically require heating at temperature of 70 °C or above to cure at a practical rate.
  • 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.
  • ECH 1-ethynyl-1-cyclohexanol
  • 2-methyl-3-butyn-2-ol 3-butyn-1-ol
  • 3-butyn-2-ol 3-methyl butynol 3-butyn-2-ol
  • propargyl alcohol 2-phenyl-2-propyn-1-ol
  • the inhibitor is selected from one or more of 1-ethynyl-1-cyclohexanol (ETCH) , tetramethyltetravinylcyclotetrasiloxane, 3-methyl butynol and/or dibutyl maleate.
  • ECH 1-ethynyl-1-cyclohexanol
  • tetramethyltetravinylcyclotetrasiloxane 3-methyl butynol and/or dibutyl maleate.
  • inhibitor concentrations as low as 1 mole of inhibitor per mole of the metal of catalyst (d) will in some instances impart satisfactory storage stability and cure rate. In other instances, inhibitor concentrations of up to 500 moles of inhibitor per mole of the metal of catalyst (d) are required.
  • the optimum concentration for a given inhibitor in a given hydrosilylation curable silicone 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 inhibitor selected is provided/available commercially when present in the composition, the inhibitor is typically present in an amount of from 0.0001-10wt. %, alternatively 0.001-5%, inhibitor, alternatively 0.0125 to 5wt. %of the composition.
  • Pot life extenders such as triazole, may be used, but are not considered necessary in the scope of the present invention.
  • the hydrosilylation curable silicone rubber coating composition may thus be free of pot life extender.
  • flame retardants examples include calcium carbonate, e.g., precipitated calcium carbonate, aluminium trihydrate (ATH) , magnesium dihydroxide (MDH) and HMH (a mixture of hydromagnesite and huntite) , chlorinated paraffins, hexabromocyclododecane, triphenyl phosphate, dimethyl methylphosphonate, tris (2, 3-dibromopropyl) phosphate (brominated tris) , and mixtures or derivatives thereof.
  • the flame retardant may be present in an amount of from 5 to 50 wt. %of the composition.
  • lubricants include tetrafluoroethylene, resin powder, graphite, fluorinated graphite, talc, boron nitride, fluorine oil, silicone oil, molybdenum disulfide, and mixtures or derivatives thereof.
  • flame retardants are typically present in an amount of from 0.1 to 5%by weight of the composition.
  • Non-reinforcing fillers may include crushed quartz, diatomaceous earths, barium sulphate, iron oxide, titanium dioxide and carbon black, talc, wollastonite.
  • Other fillers which might be used alone or in addition to the above include aluminite, calcium sulphate (anhydrite) , gypsum, calcium sulphate, magnesium carbonate, clays such as kaolin, 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.
  • Other fillers may include, aluminium oxide, silicates from the group consisting of olivine group; garnet group; aluminosilicates; ring silicates; chain silicates; and sheet silicates.
  • the olivine group comprises silicate minerals, such as but not limited to, forsterite and Mg 2 SiO 4 .
  • the garnet group comprises ground silicate minerals, such as but not limited to, pyrope; Mg 3 Al 2 Si 3 O 12 ; grossular; and Ca 2 Al 2 Si 3 O 12 .
  • Aluminosilicates comprise ground silicate minerals, such as but not limited to, sillimanite; Al 2 SiO 5 ; mullite; 3Al 2 O 3 .2SiO 2 ; kyanite; and Al 2 SiO 5 .
  • Ring silicates may be utilized as non-reinforcing fillers, these include silicate minerals, such as but not limited to, cordierite and Al 3 (Mg, Fe) 2 [Si 4 AlO 18 ] .
  • the chain silicates group comprises ground silicate minerals, such as but not limited to, wollastonite and Ca [SiO 3 ] .
  • 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; K 2 AI 14 [Si 6 Al 2 O 20 ] (OH) 4 ; pyrophyllite; Al 4 [Si 8 O 20 ] (OH) 4 ; talc; Mg 6 [Si 8 O 20 ] (OH) 4 ; serpentine for example, asbestos; Kaolinite; Al 4 [Si 4 O 10 ] (OH) 8 ; and vermiculite.
  • the fillers will be selected from one or more of fumed silica, precipitated silica, calcium carbonate, talc, mica, quartz and aluminium oxide.
  • pigments examples include titanium dioxide, chromium oxide, bismuth vanadium oxide, iron oxides and mixtures thereof.
  • the 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. Pigments are utilized to colour the composition as required. Any suitable pigment may be utilized providing it is compatible with the composition herein.
  • Suitable white pigments and/or colorants include titanium dioxide, zinc oxide, lead oxide, zinc sulfide, lithophone, zirconium oxide, and antimony oxide.
  • Suitable non-white inorganic pigments and/or colorants include, but are not limited to, iron oxide pigments such as goethite, lepidocrocite, hematite, maghemite, and magnetite black iron oxide, yellow iron oxide, brown iron oxide, and red iron oxide; blue iron pigments; chromium oxide pigments; cadmium pigments such as cadmium yellow, cadmium red, and cadmium cinnabar; bismuth pigments such as bismuth vanadate and bismuth vanadate molybdate; mixed metal oxide pigments such as cobalt titanate green; chromate and molybdate pigments such as chromium yellow, molybdate red, and molybdate orange; ultramarine pigments; cobalt oxide pigments; nickel antimony titanates; lead chrome; carbon black; lampblack, and metal effect pigments such as aluminium, copper, copper oxide, bronze, stainless steel, nickel, zinc, and brass.
  • iron oxide pigments such as goeth
  • 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, ⁇ -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, triary
  • the hydrosilylation curable silicone coating composition may be heat stabilised.
  • 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 of a metal chosen from copper, zinc, aluminum, iron, cerium, zirconium, titanium and the like.
  • 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.
  • 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 hydrosilylation curable silicone coating composition may
  • hydrosilylation curable silicone rubber coating compositions for treating textiles and fabrics comprises:
  • organopolysiloxane polymer (a) having a viscosity of from In each case component (a)
  • the viscosity of organopolysiloxane polymer (a) should be between 100 and 200,000mPa. s inclusive at 25 °C, alternatively from 1000 to150,000mPa. s at 25 °C, alternatively, from 1000mPa. s to 125,000mPa. s, alternatively from 1000mPa. s to 70,000mPa. s at 25 °C, 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.
  • optional reinforcing fillers comprising fumed silica, precipitated silica or a mixture thereof; having a particle size of at least 50 m 2 /g (BET method in accordance with ISO 9277: 2010) alternatively, 50-450m 2 /g, alternatively, 50 -400m 2 /g m 2 /g, alternatively from 50 to 300 m 2 /g, alternatively 100 -300m 2 /g (BET method in accordance with ISO 9277: 2010) ; said reinforcing fillers (b) are typically treated to render them hydrophobic and are present in an amount of from 1.0 to 50wt. %. Of the composition, alternatively of from 1 to 30wt. %. of the composition, alternatively of from 5.0 to 25wt. %. Based on the weight %of the composition;
  • an organosilicon compound having at least two, alternatively at least three Si-H groups per molecule, preferably wherein 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.
  • 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, alternatively at least three Si-H groups per molecule being present in an amount of from 0.1 to 10 wt. %of the hydrosilylation curable silicone coating composition, alternatively 0.1 to 7.5wt. %of the hydrosilylation curable silicone coating composition, alternatively 0.5 to 7.5wt. %, further alternatively from 0.5%to 5 wt. %of the hydrosilylation curable silicone coating 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 hydrosilylation curable silicone rubber coating composition; alternatively, between 0.1 and 7500ppm; alternatively, between 100 and 75000 ppm, and alternatively between 500 and 6,000 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.
  • an adhesion promoter comprising an organosilicon bisphenol adduct compound, comprising a bisphenyl unit which is not directly attached to a silicon atom, and at least one Si -H group; said Adhesion promoter (e) is typically present in the composition in an amount of from about 0.5 to 10wt. %of the composition, alternatively from 1 to 7.5 wt. %of the composition, alternatively from 1 to 5 wt. %of the composition;
  • organosilicon silicone resins selected from T silicone resins (silsesquioxanes) , DT silicone resins, MQ silicone resins, MDT silicone resins, MTQ silicone resins, QDT silicone resins or mixtures thereof in an amount of from 1-60wt. %, alternatively 1-40wt. %of the composition.
  • the total wt. % (weight %) of the composition is 100wt. %.
  • component (f) is present it is preferably an MQ type resin.
  • coated textile material described herein is a textile material coated with the cured product of the above hydrosilylation curable silicone rubber coating composition.
  • a Part A composition will comprise components (a) polymer, (b) optional reinforcing filler when present and (d) hydrosilylation cure catalyst and Part B will comprise components (a) , (c) cross-linker, reinforcing filler (b) , when present, and inhibitor, when present.
  • Component (e) the adhesion promoter is typically stored in the part B composition.
  • Additives when present in a hydrosilylation curable silicone rubber coating composition for treating textiles and fabrics 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) .
  • Part A and part B of the hydrosilylation curable silicone 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 10: 1 to 1: 10, alternatively from 5: 1 to 1: 5, alternatively from 2: 1 to 1: 2, but most preferred is a weight ratio of 1: 1.
  • 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.
  • components (a) and (b) when the latter is present) are often mixed together to form an LSR polymer base or masterbatch prior to addition with other ingredients.
  • 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 may be used to make pre-prepared concentrates commonly referred to in the industry as masterbatches.
  • one or more masterbatches may be utilized to successfully mix the ingredients to form Part A and/or Part B compositions particularly when component (b) is present.
  • a “fumed silica” masterbatch may be prepared. This is effectively an LSR silicone rubber base with silica treated in situ.
  • Parts A and B of the 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.
  • Part A and Part B compositions Prior to use the respective Part A and Part B compositions are mixed together in the desired ratio.
  • 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.
  • the hydrosilylation curable silicone rubber coating composition can be applied onto one or both sides of a textile or 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.
  • a textile or 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.
  • Curing of the hydrosilylation curable silicone coating composition of the present invention 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.
  • compositions 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 a further compatible coating, e.g., of a material providing e.g., low friction, if deemed necessary.
  • any suitable desired coat weight may be applied on the textile or fabric material such as an airbag, e.g., from 15 to 150 g/m 2 , alternatively from 15 to 100 g/m 2 , alternatively from 20 to 75 g/m 2 determined in accordance with ISO 3801.
  • the thickness of coating layer ranges from of 20 to 80 ⁇ m depending on the coating weight.
  • the textile or fabric substrate is the textile or fabric substrate
  • the textile or fabric substrate onto which the hydrosilylation curable silicone rubber coating composition is applied may be made from any suitable woven fabric, particularly a plain weave fabric, but can for example be a knitted or nonwoven fabric.
  • the fabric or textile material may be made from synthetic fibres or blends of natural and synthetic fibres, for example polyamide fibres such as Nylon 6, Nylon 66 and Nylon 46; 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.
  • the airbag When treating an airbag, 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.
  • the woven fabric Prior to coating with the hydrosilylation curable silicone rubber coating composition described hereinthe woven fabric is preferably washed with water and dried.
  • the fabric 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 textiles; however, it can be difficult to get coatings to adhere to polyamide and polyester airbags, hence the need for adhesion promoters such as component (e) herein which was surprisingly found to be suitable as an adhesion promoter for airbag coatings because when it replaced standard adhesion promoters it provided the necessary adhesion between the coating and the textile or fabric substrate and advantageously significantly reduced TVOC emissions to levels preferred by vehicle manufacturers and OEMs.
  • Coatings made by curing the composition herein using adhesion promoter (e) were able to stabilize the fabric against pre-mature pressure loss upon deployment and enable the airbag to deploy, inflate and protect the occupants within the milliseconds after the first impact in a collision.
  • the resulting coatings had the necessary coating integrity, cured mechanical/viscoelastic properties and satisfactory surface lubricity are all critical features that are not guaranteed when you swap adhesion promoters.
  • the coating compositions described herein are designed therefore to have particularly good adhesion and film forming properties immediately on contacting the fabric, so that film formation on the surface of the fabric being coated is uniform. Preferably they also have good penetration into the fabric.
  • the airbag obtained by coating an uncoated airbag fabric with the hydrosilylation curable silicone coating composition described herein has at least one coating layer formed of a cured product from the hydrosilylation curable silicone coating composition described herein.
  • 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.
  • This technology can be used in any suitable textile and/or fabric application but is particularly suited for airbags applications particularly in the automobile market but also for e.g., escape chutes from aircraft.
  • the coating formed by the curing of the hydrosilylation curable silicone coating composition described herein has excellent adhesion to substrate used for airbag fabrics.
  • the excellent adhesion durability to various fabrics provides the coated fabrics with long-term stability under heat and humidity aging conditions, thereby enhancing airbag reliability.
  • adhesion promoter e
  • the coatings give carbon emission results of less than 50 ⁇ gC/g when tested in accordance with VDA277 which is a significant improvement in comparison to standard adhesion promoters used in the industry resulting in more environmentally friendly and sustainable airbags and better in-car air quality.
  • the composition described herein containing component (e) as the adhesion promoter shows very good flowability, mechanical strength, improved adhesion to woven fabrics and lower total volatile organic compounds (TVOC) versus traditional airbag coating LSR materials using organometallic catalyst and alkoxysilane as adhesion package.
  • compositions are defined in weight % (wt. %) unless otherwise stated.
  • 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.
  • compositions were prepared and were analysed for their suitability as coatings for textiles, particularly coating coatings for airbag.
  • the liquid silicone rubber compositions prepared were prepared as two-part compositions, part A and part B. To make the final compositions the parts A & B were intermixed before cure. The composition was kept in two parts prior to use to ensure premature cure was avoided.
  • the compositions of the parts A and B are provided below in Tables 1a to 1d and prior to use the compositions were mixed together in a 1 : 1 weight ratio.
  • Table 1a Part A and Part B compositions for Comparative Examples 1 & 2 and Ex. 1 & 2 (wt. %)
  • Table 1b Part A and Part B compositions for Comparative Examples 3 & 4 and Ex. 3 & 4 (wt. %)
  • Comparative example 7 is a liquid silicone rubber composition designed for injection molding.
  • Silicone Polymer 1 was a vinyl terminated polydimethylsiloxane having a viscosity of approximately 60,000 mPa. s measured using a Brookfield Cone/Plate viscometer, using spindle CP-52 at 1 rpm, based on ASTM D 4287.
  • Silicone Polymer 2 was a vinyl terminated polydimethylsiloxane having a viscosity of approximately 10,000 mPa. s measured using a Brookfield Cone/Plate viscometer, using spindle CP-52 at 1 rpm, based on ASTM D 4287.
  • Silicone Polymer 3 was a vinyl terminated polydimethylsiloxane having a viscosity of approximately 2,000 mPa. s measured using a Brookfield Cone/Plate viscometer, using spindle CP-52 at 3 rpm, based on ASTM D 4287.
  • Masterbatch 1 was a mixture of silicone polymer 1 (73wt%) and fumed silica (27wt%) sold as CAB-O-SIL TM MS-75D fumed silica (commercially available from Cabot Corporation) which was treated in situ with hexamethyldisilazane (HMDZ) ;
  • Silicone resin MB1 was a mixture of 73 wt. %of polymer 1 and an MQ silicone resin: (27 wt. %) of the structure M 37 M Vi 5 Q 58 OH 8 ,
  • Silicone resin MB2 was a mixture of 67 wt. %of polymer 3 and an MQ silicone resin: (33 wt. %) of the structure M 37 M Vi 5 Q 58 OH 8 ,
  • Karstedt’s Catalyst was a version of Karstedt′sCatalyst containing 5,000ppm Pt;
  • Cross-linker 1 was a trimethylsilyl terminated Dimethyl, methylhydrogen siloxane having a viscosity of 15 mm 2 /s (cSt) , measured in accordance with Dow Corporate test method CTM 0004, (based on ASTM D-445) and 0.8 wt. %H;
  • Cross-linker 2 was a trimethylsilyl terminated methylhydrogen siloxane having a viscosity of 30 mm 2 /s (cSt) , measured in accordance with Dow Corporate test method CTM 0004, (based on ASTM D-445) and 1.6 wt. %H;
  • Cross-linker 3 was a trimethylalkyl terminated dimethyl, methylhydrogen siloxane having a viscosity of 45 mm 2 /s (cSt) , measured in accordance with Dow Corporate test method CTM 0004, (based on ASTM D-445) and 0.7 wt. %H;
  • ETCH was Ethynyl Cyclohexanol
  • Adhesion Catalyst was a mixture of 50 wt. %zirconium acetylacetonate in polymer 2
  • Alkoxysilane was Gamma-glycidoxypropyl trimethoxy silane
  • HMH filler was UltraCarb TM LH3C which is a mixture of Huntite and /Hydromagnesite, wt. /wt. ratio 4: 6 commercially available from LKAB;
  • composition Whilst any suitable method can be used, however unless the composition is to be used immediately it is prepared in two parts, part A and part B with a view to prevent premature curing.
  • an in-situ treated fumed silica masterbatch was prepared in a Kneader mixer by mixing the ingredients depicted in Table 1 and the stripping off residual water and treatment agents. Also, when present, the silicone resins (f) were pre-mixed with component (a) before mixing with the other ingredients.
  • Each part A and part B composition was then prepared using the components identified in Tables 1a to 1d.
  • the respective part A composition and part B composition were then mixed together and the resulting composition was either coated onto a textile material or was prepared for the physical property testing described below.
  • Coating onto the airbags substrates used in the examples was undertaken manually using a lab coater commercially available from Werner Mathis AG.
  • the coating temperature utilised was 190°C and the curing time was 1min duration.
  • the coat weight was about around 25gm 2 determined in accordance with ISO 3801.
  • Zero-shear viscosity ( ⁇ o ) 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 using an Anton-Parr MCR-301 rheometer equipped with cone-and-plate fixtures at a series of low shear rates, such as 0.01 s -1 , 0.1 s -1 and 1.0 s -1 while not exceeding the torque limits of the transducer.
  • Table 2a Zero-shear (ZS) Viscosity measurements (Pa. s) at 25°C of the final compositions (Part A + Part B) as depicted in Tables 1a and 1b for comparative examples C. 1 to C. 4 and Ex. 1 to 4 prior to cure.
  • ZS Zero-shear
  • Table 2b Zero shear Viscosity measurements (Pa. s) at 25°C of the final compositions (Part A + Part B) as depicted in Tables 1c and 1d for comparative examples C. 5, 6 and 7 and Ex. 5 to 8 prior to cure.
  • Sheets of the cured silicone materials were also prepared in order to evaluate the physical properties of the samples. They were molded to 2mm sheet by compression molding at a curing temperature of approximately 120°C for a period of 10 minutes. Samples were not post-cured.
  • a 2 mm-thick cured silicone rubber specimen was obtained by subjecting the liquid curable silicone rubber composition to press curing for 10 min at 120°C under a pressure of 30 tons. Hardness of the silicone rubber was measured by Shore A durometer in accordance with ASTM D 2240. Tensile strength, elongation at break and modulus results were determined in accordance with ASTM D412, tear strength was determined in accordance with ASTM D624 using DIE C and the specific gravity (relative density) was measured in accordance with ASTM D792 using test method A
  • Table 3a Physical Property measurements of the cured products of the compositions as depicted in Tables 1a and 1b comparative examples C. 1 to C. 4 and Ex. 1 to 4.
  • Table 3b Physical Property measurements of the cured products of the compositions as depicted in Tables 1c and 1d for comparative examples C. 5, 6 and 7 and Ex. 5 to 8.
  • An airbag fabric made from 420dtex polyamide 66 (PA66) were obtained (dtex is the weight in grams a sewing thread of 10,000 m length of the textile thread weighs) and was used as the textile support for coatings of the compositions in Tables 1ato 1d above which were applied thereto and cured for 1 min at 190°C.
  • PA66 polyamide 66
  • the coatings for each coated sample underwent TVOC analysis in accordance with the VDA277 test method.
  • the target which was sought to be achieved was a value of less than or equal to ( ⁇ ) 50 ⁇ gC/g
  • Table 4a TVOC results determined in accordance with VDA277 for the composition of Tables 1a and 1b on a 420d PA66 from with a target of ⁇ 50 ⁇ gC/g
  • Table 4b TVOC results determined in accordance with VDA277 for the composition of Tables 1c and 1d with a target of ⁇ 50 ⁇ gC/g
  • pin hole is used to represent a failure mode different from delamination. Whilst delamination is intended to indicate adhesion failure the term pin hole does not. Pin hole is used to identify results after the scrub/flex abrasion test, whereby some small or tiny holes can d be observed (under light) on the coated fabric. These pin holes are usually due to the movement of warp-weft yarns of the woven fabric but not adhesion failure.
  • the examples show that the composition described herein containing component (e) as the adhesion promoter shows very good flowability, mechanical strength, improved adhesion to woven fabrics and lower total volatile organic compounds (TVOC) versus traditional airbag coating LSR materials using organometallic catalyst and alkoxysilane as adhesion package.
  • component (e) as the adhesion promoter shows very good flowability, mechanical strength, improved adhesion to woven fabrics and lower total volatile organic compounds (TVOC) versus traditional airbag coating LSR materials using organometallic catalyst and alkoxysilane as adhesion package.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Dispersion Chemistry (AREA)
  • Paints Or Removers (AREA)

Abstract

La présente invention concerne des compositions de revêtement de caoutchouc de silicone durcissables par hydrosilylation pour le traitement de textiles et de tissus, ces compositions contenant un promoteur d'adhérence comprenant un composé de produit d'addition organosilicium bisphénol, comprenant une unité bisphényle qui n'est pas directement attachée à un atome de silicium, et au moins un groupe Si-H. La présente invention s'étend également à des textiles et des tissus, tels que des dispositifs de retenue de sécurité gonflables, par exemple des coussins de sécurité gonflables, revêtus d'un produit durci des compositions de revêtement de caoutchouc de silicone durcissables par hydrosilylation, et à un procédé de revêtement desdits textiles et tissus, tels que des dispositifs de retenue de sécurité gonflables, par exemple des coussins de sécurité gonflables, par la composition de revêtement de caoutchouc de silicone durcissable par hydrosilylation. Les compositions de revêtement de caoutchouc silicone durcissables par hydrosilylation présentent une excellente aptitude à l'écoulement sur les surfaces textiles et les textiles revêtus par un produit durci des compositions de revêtement de caoutchouc de silicone durcissables par hydrosilylation de la présente invention sont considérés comme présentant une adhérence améliorée aux tissus tissés et des composés organiques volatils totaux (COVT) inférieurs à ceux observés avec des matériaux de revêtement standards utilisés pour traiter lesdits textiles et tissus.
PCT/CN2023/125458 2023-10-19 2023-10-19 Revêtements de silicone pour textiles et tissus Pending WO2025081423A1 (fr)

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Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3419593A (en) 1965-05-17 1968-12-31 Dow Corning Catalysts for the reaction of = sih with organic compounds containing aliphatic unsaturation
US3445420A (en) 1966-06-23 1969-05-20 Dow Corning Acetylenic inhibited platinum catalyzed organopolysiloxane composition
US3715334A (en) 1970-11-27 1973-02-06 Gen Electric Platinum-vinylsiloxanes
US3814730A (en) 1970-08-06 1974-06-04 Gen Electric Platinum complexes of unsaturated siloxanes and platinum containing organopolysiloxanes
US3989667A (en) 1974-12-02 1976-11-02 Dow Corning Corporation Olefinic siloxanes as platinum inhibitors
EP0646672A1 (fr) * 1993-08-26 1995-04-05 Wacker-Chemie GmbH Tissus enduits pour coussins d'air
US6605734B2 (en) 2001-12-07 2003-08-12 Dow Corning Corporation Alkene-platinum-silyl complexes
US20180273691A1 (en) * 2015-09-25 2018-09-27 Bluestar Silicones France Sas Silicone composition and process useful for improving the crease resistance and abrasion resistance of airbags, intended for protecting a vehicle occupant
US20220356370A1 (en) * 2019-07-30 2022-11-10 Dow Silicones Corporation Silicone coatings for air bags
WO2023076351A1 (fr) * 2021-10-29 2023-05-04 Dow Toray Co., Ltd. Composition de caoutchouc de silicone pour revêtement textile, et textile revêtu de caoutchouc de silicone

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3419593A (en) 1965-05-17 1968-12-31 Dow Corning Catalysts for the reaction of = sih with organic compounds containing aliphatic unsaturation
US3445420A (en) 1966-06-23 1969-05-20 Dow Corning Acetylenic inhibited platinum catalyzed organopolysiloxane composition
US3814730A (en) 1970-08-06 1974-06-04 Gen Electric Platinum complexes of unsaturated siloxanes and platinum containing organopolysiloxanes
US3715334A (en) 1970-11-27 1973-02-06 Gen Electric Platinum-vinylsiloxanes
US3989667A (en) 1974-12-02 1976-11-02 Dow Corning Corporation Olefinic siloxanes as platinum inhibitors
EP0646672A1 (fr) * 1993-08-26 1995-04-05 Wacker-Chemie GmbH Tissus enduits pour coussins d'air
US6605734B2 (en) 2001-12-07 2003-08-12 Dow Corning Corporation Alkene-platinum-silyl complexes
US20180273691A1 (en) * 2015-09-25 2018-09-27 Bluestar Silicones France Sas Silicone composition and process useful for improving the crease resistance and abrasion resistance of airbags, intended for protecting a vehicle occupant
US20220356370A1 (en) * 2019-07-30 2022-11-10 Dow Silicones Corporation Silicone coatings for air bags
WO2023076351A1 (fr) * 2021-10-29 2023-05-04 Dow Toray Co., Ltd. Composition de caoutchouc de silicone pour revêtement textile, et textile revêtu de caoutchouc de silicone

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