WO2022067597A1 - Élastomères de mousse de silicone et leurs utilisations - Google Patents

Élastomères de mousse de silicone et leurs utilisations Download PDF

Info

Publication number
WO2022067597A1
WO2022067597A1 PCT/CN2020/119143 CN2020119143W WO2022067597A1 WO 2022067597 A1 WO2022067597 A1 WO 2022067597A1 CN 2020119143 W CN2020119143 W CN 2020119143W WO 2022067597 A1 WO2022067597 A1 WO 2022067597A1
Authority
WO
WIPO (PCT)
Prior art keywords
composition
groups
foam
curable
accordance
Prior art date
Application number
PCT/CN2020/119143
Other languages
English (en)
Inventor
Yi Guo
Xuesi YAO
Rui Yang
Rui Wang
Lu Zou
Original Assignee
Dow Silicones Corporation
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Dow Silicones Corporation filed Critical Dow Silicones Corporation
Priority to PCT/CN2020/119143 priority Critical patent/WO2022067597A1/fr
Priority to CN202080103608.0A priority patent/CN115989273A/zh
Publication of WO2022067597A1 publication Critical patent/WO2022067597A1/fr

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
    • C08L83/04—Polysiloxanes
    • 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

Definitions

  • This disclosure relates to curable and foamable silicone compositions, silicone foam elastomers made using said compositions, and methods for making said silicone foamed elastomers in the form of silicone foam elastomer formed-in-place foam gaskets (FIPFGs) .
  • FIPFGs silicone foam elastomer formed-in-place foam gaskets
  • gaskets have been manufactured by either die-cutting a gasket out of an elastomeric sheet material, or shaping a gasket by injection-molding of an elastomeric mix or the like. Both these methods require expensive tools such as punches and molds and can result in a significant amount of waste all of which can add cost to the production costs of the final product.
  • FIPFG Formmed in Place Foam Gasket
  • the foaming material is usually applied, in the case of a formed-in-place foam gasket, as a bead or thread of a fluid elastomer composition from a suitable applicator onto a target surface which effectively creates a mold for the desired gasket.
  • the applicators used may be pre-programmed robot applicators so that the introduction of the fluid elastomer thread may be controlled to provide a gasket having a desired shape and minimising waste. Once, the fluid elastomer composition has been completely introduced it is cured in place.
  • RTV room temperature vulcanization
  • foaming mechanism uses the hydrogen generated as a by-product during the curing process of such compositions to create the foam as a result of the reaction of hydroxyl-functional components with silicon-bonded hydrogen atoms.
  • Curable and foamable silicone compositions of this type contain the following components
  • organohydrogensiloxane having at least two alternatively at least three Si-H groups per molecule
  • a catalyst comprising or consisting of a platinum group metal or a compound thereof.
  • components a) , b) and c) may be chosen dependent on the physical properties and end use desired for the resulting silicone foamed elastomers but such compositions may also require one or more additives for this purpose. These may include, for the sake of example, one or more fillers and/or thixotropic agents, some of which may function as both filler and thixotropic agents.
  • the curable and foamable silicone composition should have a sufficiently low viscosity to be readily dispensable but needs to be sufficiently thixotropic so that once applied and before and/or during cure and foaming the dispensed fluid elastomer composition is non-slumping and has good dimensional stability so that there is essentially no change in shape or position of the composition during and after curing.
  • the resulting silicone foam gaskets generated from a dispensed curable and foamable silicone composition need to have good compression forces and compression set to ensure sealing performance and reliability.
  • the preferred thixotropic agents relied upon in curable and foamable silicone composition are inorganic thixotropic agents such as silica and calcium carbonate.
  • inorganic thixotropic agents such as silica and calcium carbonate.
  • these also act as reinforcing or semi-reinforcing fillers and as a consequence the level of such thixotropic agents in the composition is limited to avoid significant increases in viscosity and composition density and thereby having a detrimental effect on the dispensability of the fluid elastomer composition through the applicator, potentially causing blockages in the applicator and leading to the resulting cured foam having a high density and hardness.
  • the compression set may also become an issue for those products with too much filler.
  • curable and foamable silicone composition comprising the following components: -
  • organosilicon compound having at least two, alternatively at least three Si-H groups per molecule
  • a hydrosilylation catalyst comprising or consisting of a platinum group metal or a compound thereof;
  • a thixotropic agent selected from silica, calcium carbonate, talc or a mixture thereof in an amount of from 2 to 5 wt. %of the composition and
  • a co-thixotropic agent comprising one or more silyl-modified polyethers in an amount of from 0.5 to 3wt. %of the composition.
  • a co-thixotropic agent comprising one or more silyl-modified polyethers (SMP) (component f) in combination with component (e) improves the thixotropic nature of the curable and foamable silicone composition without the detrimental effects caused by the introduction of higher levels of thixotropic agents selected from silica and/or calcium carbonate.
  • SMP silyl-modified polyethers
  • a silicone foamed elastomer obtained or obtainable by mixing and curing the curable and foamable silicone composition described above and/or a formed-in-place foam gasket (FIPFG) obtained or obtainable by mixing and curing the curable and foamable silicone compositions described above.
  • a silicone foamed elastomer or a formed-in-place foam gasket (FIPFG) comprising the cured product of the curable and foamable silicone composition described above.
  • a silicone foamed elastomer and/or a formed-in-place foam gasket (FIPFG) by mixing and curing a curable and foamable silicone composition comprising the following components
  • organohydrogensiloxane having at least two alternatively at least three Si-H groups per molecule
  • a hydrosilylation catalyst comprising or consisting of a platinum group metal or a compound thereof;
  • a thixotropic agent selected from silica, calcium carbonate or a mixture thereof in an amount of from 2 to 5 wt. %of the composition and
  • a co-thixotropic agent comprising one or more silyl-modified polyethers in an amount of from 0.5 to 3wt. %of the composition.
  • a curable and foamable silicone composition to make a silicone foamed elastomer and/or a formed-in-place foam gasket (FIPFG) .
  • the silicone foamed elastomer is provided as a formed-in-place foam gasket (FIPFG) .
  • the foamed silicone elastomer is the reaction product of components (a) and (b) , catalysed by component (d) , and the structure of the resulting foam is provided by the hydrogen released due to the reaction of components (b) and (c) also catalysed by component (d) .
  • the reaction product may also be formed in the presence of one or more optional additives. Such additives, if utilized, may be inert to, or reactive with, other components of the composition.
  • Hydrocarbyl means a monovalent hydrocarbon group which may be substituted or unsubstituted. Specific examples of hydrocarbyl groups include alkyl groups, alkenyl groups, alkynyl groups, aryl groups, aralkyl groups, etc.
  • Alkyl means an acyclic, branched or unbranched, saturated monovalent hydrocarbon group.
  • Aryl means a cyclic, fully unsaturated, hydrocarbon group.
  • Aralkyl means an alkyl group having a pendant and/or terminal aryl group or an aryl group having a pendant alkyl group.
  • Alkenylene means an acyclic, branched or unbranched, divalent hydrocarbon group having one or more carbon-carbon double bonds.
  • Alkylene means an acyclic, branched or unbranched, saturated divalent hydrocarbon group.
  • Alkynylene means an acyclic, branched or unbranched, divalent hydrocarbon group having one or more carbon-carbon triple bonds.
  • Alrylene means a cyclic, fully unsaturated, divalent hydrocarbon group.
  • substituted as used in relation to another group, e.g. a hydrocarbyl group, means, unless indicated otherwise, one or more hydrogen atoms in the hydrocarbyl group has been replaced with another substituent.
  • substituents include, for example, halogen atoms such as chlorine, fluorine, bromine, and iodine; halogen atom containing groups such as chloromethyl, perfluorobutyl, trifluoroethyl, and nonafluorohexyl; oxygen atoms; oxygen atom containing groups such as (meth) acrylic and carboxyl; nitrogen atoms; nitrogen atom containing groups such as amines, amino-functional groups, amido-functional groups, and cyano-functional groups; sulphur atoms; and sulphur atom containing groups such as mercapto groups.
  • M, D, T and Q units are generally represented as R u SiO (4–u) /2, where u is 3, 2, 1, and 0 for M, D, T, and Q, respectively, and R is an independently selected hydrocarbyl group.
  • the M, D, T, Q designate one (Mono) , two (Di) , three (Tri) , or four (Quad) oxygen atoms covalently bonded to a silicon atom that is linked into the rest of the molecular structure.
  • Component (a) is a polydiorganosiloxane having at least two unsaturated groups per molecule, which unsaturated groups are selected from alkenyl or alkynyl groups. Alternatively, component (a) has at least three unsaturated groups per molecule.
  • the unsaturated groups of component (a) may be terminal, pendent, or in both locations in component (a) .
  • the unsaturated group may be an alkenyl group and/or an alkynyl group.
  • Alkenyl is exemplified by, but not limited to, vinyl, allyl, methallyl, propenyl, and hexenyl groups.
  • Alkenyl groups may 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 may be exemplified by, but not limited to, ethynyl, propynyl, and butynyl groups.
  • Alkynyl groups may 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.
  • Component (a) has multiple units of the formula (I) :
  • each R is independently selected from an aliphatic hydrocarbyl, aromatic hydrocarbyl, or organyl group (that is any organic substituent group, regardless of functional type, having one free valence at a carbon atom) .
  • Saturated aliphatic hydrocarbyls are exemplified by, but not limited to alkyl groups such as methyl, ethyl, propyl, pentyl, octyl, undecyl, and octadecyl and cycloalkyl groups such as cyclohexyl.
  • Unsaturated aliphatic hydrocarbyls are exemplified by, but not limited to the alkenyl groups and alkynyl groups described above.
  • Aromatic hydrocarbon groups are exemplified by, but not limited to, phenyl, tolyl, xylyl, benzyl, styryl, and 2-phenylethyl.
  • Organyl groups are exemplified by, but not limited to, halogenated alkyl groups (excluding fluoro containing groups) such as chloromethyl and 3-chloropropyl; nitrogen containing groups such as amino groups, amido groups, imino 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. The subscript “a” is 0, 1, 2 or 3.
  • Siloxy units may be described by a shorthand (abbreviated) nomenclature, namely - “M, “ “D, “ “T, “ and “Q” , when R is a methyl group (further teaching on silicone nomenclature may be found in Walter Noll, Chemistry and Technology of Silicones, dated 1962, Chapter I, pages 1-9) .
  • the polydiorganosiloxane of component (a) is substantially linear but may contain a proportion of however, there can be some 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.
  • Examples of typical groups on component (a) include mainly alkenyl, alkynyl, alkyl, and/or aryl groups, alternatively alkenyl, alkyl, and/or aryl groups.
  • the groups may be in pendent position (on a D or T siloxy unit) or may be terminal (on an M siloxy unit) .
  • the silicon-bonded organic groups attached to component (a) other than alkenyl groups are typically selected from monovalent saturated hydrocarbon groups, which typically contain from 1 to 10 carbon atoms, and monovalent aromatic hydrocarbon groups, which typically contain from 6 to 12 carbon atoms, which are unsubstituted or substituted with the groups that do not interfere with curing of this inventive composition, such as halogen atoms.
  • Preferred species of the silicon-bonded organic groups are, for example, alkyl groups such as methyl, ethyl, and propyl; and aryl groups such as phenyl.
  • Component (a) may be selected from polydimethylsiloxanes, alkylmethylpolysiloxanes, alkylarylpolysiloxanes or copolymers thereof (where reference to alkyl means an alkyl group having two or more carbons) containing e.g. alkenyl and/or alkynyl groups and may have any suitable terminal groups, for example, they may be trialkyl terminated, alkenyldialkyl terminated alkynyldialkyl terminated or may be terminated with any other suitable terminal group combination providing each polymer contains at least two unsaturated groups selected from alkenyl and alkynyl groups per molecule. In one embodiment the terminal groups of such a polymer has no silanol terminal groups.
  • 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.
  • the generally substantially linear organopolysiloxane of component (a) is typically a flowable liquid.
  • the substantially linear organopolysiloxane has a viscosity of from 100 to 1,000,000 mPa. s, alternatively from 100 to 100,000 mPa. s, at 25 °C. Viscosity may be measured at 25 °C using either a rotational viscometer with spindle LV-4 (designed for viscosities in the range between 1,000-2,000,000mPa. s) or a rotational viscometer with spindle LV-1 (designed for viscosities in the range between 15 -20,000mPa. s) for viscosities less than 1000mPa. s and adapting the speed according to the polymer viscosity.
  • Component (b) is an organosilicon compound having at least two, alternatively at least three Si-H groups per molecule.
  • the organosilicon compound (b) operates as a cross-linker for curing component (a) , by the addition reaction of the silicon-bonded hydrogen atoms with the unsaturated groups in component (a) catalysed by component (d) described below.
  • Component (b) normally contains three or more silicon-bonded hydrogen atoms so that the hydrogen atoms of this component can sufficiently react with the unsaturated groups of component (a) to form a network structure therewith and thereby cure the composition.
  • Some or all of Component (b) may alternatively have two silicon bonded hydrogen atoms per molecule when component (a) has greater than (>) 2 unsaturated groups, alternatively alkenyl groups per molecule.
  • Component (b) may be a siloxane e.g. an organohydrogensiloxane or a silane e.g. a monosilane, disilane, trisilane, or polysilane providing each molecule has at least two, alternatively at least three Si-H groups per molecule.
  • the silicon-bonded hydrogen atoms can be located at terminal, pendant, or at both terminal and pendant positions.
  • Cyclosilanes and cyclosiloxanes typically have from 3 to 12 silicon atoms, alternatively from 3 to 10 silicon atoms, alternatively from 3 to 4 silicon atoms.
  • component (b) When component (b) is a siloxane it may comprise an organohydrogensiloxane, which can be a disiloxane, trisiloxane, or polysiloxane.
  • the organohydrogensiloxane may comprise any combination of M, D, T and/or Q siloxy units, so long as component (b) includes at least two silicon-bonded hydrogen atoms.
  • These siloxy units can be combined in various manners to form cyclic, linear, branched and/or resinous (three-dimensional networked) structures.
  • Component (b) may be monomeric, polymeric, oligomeric, linear, branched, cyclic, and/or resinous depending on the selection of M, D, T, and/or Q units.
  • component (b) examples include but are not limited to:
  • copolymers composed of (CH 3 ) 3 SiO 1/2 units, (CH 3 ) 2 HSiO 1/2 units, and SiO 4/2 units;
  • the viscosity of this component is not specifically restricted, it may typically be from 0.001 to 50 Pa. s at 25°C relying using either a rotational viscometer with spindle LV-4 (designed for viscosities in the range between 1,000-2,000,000mPa. s) or a rotational viscometer with spindle LV-1 (designed for viscosities in the range between 15 -20,000mPa. s) for viscosities less than 1000mPa. s and adapting the speed according to the polymer viscosity.
  • Component (b) is typically added in an amount such that the molar ratio of the silicon-bonded hydrogen atoms in component (b) to that of all unsaturated groups in the composition and the number of -OH groups in component (c) is from 0.5: 1 to 20: 1; alternatively of from 0.5: 1 to 5: 1, alternatively from 0.6: 1 to 3: 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 composition to increase when heated.
  • the amounts of each group mentioned in the above ratio, e.g. silicon-bonded hydrogen (Si-H) content of organohydrogenpolysiloxane (b) may be determined using quantitative infra-red analysis in accordance with ASTM E168, if desired.
  • component (b) is present in the composition in an amount of from 0.5 to10 wt. %of the total composition which amount is determined dependent on the required molar ratio of the total number of the silicon-bonded hydrogen atoms in component (b) to the total number of all alkenyl and alkynyl groups in component (a) and the amount of hydroxyl groups in component (c) .
  • Component (c) is one or more hydroxyl-containing blowing agents which will react with the cross-linker (b) in the presence of component (d) the catalyst.
  • Each component (c) has at least one OH group, alternatively at least two OH groups, and alternatively three or more OH groups.
  • the OH group (s) can react with the Si-H groups of component (b) , thereby generating hydrogen gas, which is relied upon to generate the foam.
  • Each component (c) may be a suitable alcohol.
  • These may be selected from aliphatic organic alcohols having from 1 to 12 carbon atoms such as low molecular weight alcohols including, but are not limited to, methanol, ethanol, propanol, isopropanol, and the like or alternatively, benzyl alcohol.
  • component (c) may be a diol.
  • suitable diols include, but are not limited to, methylene glycol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butane diol, bisphenol A, 1, 4-butanediol, 1, 3-propanediol, 1, 5-pentanediol, 1, 7-heptanediol, 1, 2-hexanediol, triethylene glycol, tripropylene glycol neopentyl glycol, and combinations thereof.
  • component (c) may be a triol.
  • component (c) is selected from the group of low-boiling alcohols.
  • Such alcohols generally have a boiling point lower than about 120°C.
  • the alcohols may or may not be anhydrous, but anhydrous (containing less than 1 wt. %) water based on weight of alcohol is generally preferred.
  • Other suitable blowing agents are described in US4550125, US6476080, and US20140024731, which are incorporated herein by reference.
  • Component (c) is present in an amount to provide a OH content of from about 10 parts per million (ppm) to 50,000ppm, alternatively about 100ppm to 20,000ppm, alternatively about 500ppm to 10,000 ppm, alternatively about 500 to about 7500 ppm.
  • component (c) is selected from the group of Si-OH polymers.
  • the chemical blowing agent component (c) is selected from the group consisting of organosilanes and organosiloxanes having at least one silanol (Si-OH) group.
  • Such compounds can have structures similar to those described above for components A) and B) .
  • suitable OH-functional compounds include dialkyl siloxanes, such as OH-terminated dimethyl siloxanes.
  • Such siloxanes may have a relatively low viscosity, such as about 10 to about 5,000 mPa. s, about 10 to about 2,500 mPa. s, about 10 to about 1,000 mPa. s, about 10 to about 500 mPa. s, or about 10 to about 100 mPa. s.
  • the composition is substantially free of OH-functional components other than component (c) that facilitate release of hydrogen gas during formation of the foamed silicone elastomer.
  • substantially free it is generally meant that the composition includes ⁇ 5, ⁇ 4, ⁇ 3, ⁇ 2, ⁇ 1, approaching 0, or 0 wt. %of such OH-functional components.
  • Component (d) is a catalyst comprising or consisting of a platinum group metal or a compound thereof.
  • platinum group it is meant ruthenium, rhodium, palladium, osmium, iridium and platinum and complexes thereof. Platinum and platinum compounds are preferred due to the high activity level of these catalysts in hydrosilylation reactions.
  • Examples of preferred hydrosilylation catalysts (d) include but are not limited to platinum black, platinum on various solid supports, chloroplatinic acids, alcohol solutions of chloroplatinic acid, and complexes of chloroplatinic acid with ethylenically unsaturated compounds such as olefins and organosiloxanes containing ethylenically unsaturated silicon-bonded hydrocarbon groups.
  • the catalyst (d) can be platinum metal, platinum metal deposited on a carrier, such as silica gel or powdered charcoal, or a compound or complex of a platinum group metal.
  • Suitable platinum-based catalysts 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
  • the hydrosilylation catalyst (d) when present, is present in the total composition in a catalytic amount, i.e. an amount or quantity sufficient to promote a reaction or curing thereof at desired conditions. Varying levels of the hydrosilylation catalyst (d) can be used to tailor reaction rate and cure kinetics.
  • the catalytic amount of the hydrosilylation catalyst (d) is generally between 0.01 ppm, and 10,000 parts by weight of platinum-group metal, per million parts (ppm) , based on the combined weight of the composition components (a) and (b) ; alternatively between 0.01 and 5000 ppm; alternatively between 0.01 and 3,000 ppm, and alternatively between 0.01 and 1,000 ppm.
  • the catalytic amount of the catalyst may range from 0.01 to 1,000 ppm, alternatively 0.01 to 750 ppm, alternatively 0.01 to 500 ppm and alternatively 0.01 to 100 ppm of metal based on the weight of the composition.
  • 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. Typically, dependent on the form/concentration in which the catalyst package is provided the amount of catalyst present will be within the range of from 0.001 to 3.0 wt. %of the composition.
  • Component (e) is a thixotropic agent which, when added to the composition can hold the composition reliant on surface tension but which can separate or slide when sufficient force is applied causing thixotropy or shear-thinning to occur where viscosity is non-Newtonian and becomes lower as the shearing force or time increases.
  • the thixotropic agent may comprise suitable silicas, e.g. precipitated silica, fumed silica and the like, calcium carbonate and/or talc.
  • the reinforcing effect is similar as both the thixotropic effects and the reinforcing effects are, without being tied to current theories, believed to be caused through interactions between silicone polymers and the filler surface.
  • Increased levels of silica and /or calcium carbonate would lead to a greater thixotropic effect and increases in elastomeric properties of subsequently cured compositions, such as tensile strength.
  • thixotropic agent (e) may contain one or more of precipitated calcium carbonate, ground calcium carbonate, fumed silica, colloidal silica and/or precipitated silica.
  • the surface area of the thixotropic agent (e) is at least 15 m 2 /g in the case of precipitated calcium carbonate measured in accordance with the BET method in accordance with ISO 9277: 2010, alternatively 15 to 50 m 2 /g, alternatively, 15 to 25 m 2 /g in the case of precipitated calcium carbonate.
  • Silica thixotropic agents (e) have a typical surface area of at least 50 m 2 /g.
  • high surface area fumed silica and/or high surface area precipitated silica may have surface areas of from 75 to 450 m 2 /g measured using the BET method in accordance with ISO 9277: 2010, alternatively of from 100 to 300 m 2 /g using the BET method in accordance with ISO 9277: 2010.
  • the thixotropic agent is typically present in an amount of from 2 to 5 wt. %of the composition. It was found that if greater amounts of silica were added a reduction in compression set can be caused.
  • Component (f) curable and foamable silicone composition herein is one or more silyl-modified polyethers in an amount of from 0.5 to 3wt. %of the composition.
  • silyl modified polyether we mean a polymer having a polyether backbone together with and at least two (R 10 ) m (Y 1 ) 3-m –Si groups per molecule where each R 10 is hydroxyl or a hydrolysable group, each Y 1 is an alkyl group containing from 1 to 8 carbons and m is 1, 2 or 3.
  • the (R 10 ) m (Y 1 ) 3-m –Si groups of silyl modified polyether (f) may be linked to the polyether backbone via any suitable linkage or may be directly bonded where appropriate to a polyether.
  • the (R 10 ) m (Y 1 ) 3-m –Si groups may be terminal groups linked to the polyether polymer backbone via the following
  • R 10 , Y 1 and m are as hereinbefore described, D is a divalent C 2 –6 alkylene group, alternatively a C 2-4 alkylene group, alternatively an ethylene or propylene group and k is 1 or 0.
  • Each substituent R 10 in an (R 10 ) m (Y 1 ) 3-m –Si group may independently be a hydroxyl group or a hydrolysable group.
  • the hydrolysable groups may be selected from acyloxy groups (for example, acetoxy, octanoyloxy, and benzoyloxy groups) ; ketoximino groups (for example dimethyl ketoximo, and isobutylketoximino) ; alkoxy groups (for example methoxy, ethoxy and propoxy) and alkenyloxy groups (for example isopropenyloxy and 1-ethyl-2-methylvinyloxy) .
  • each R is an OH group or an alkoxy group having from 1 to 10 carbons, alternatively an OH group or an alkoxy group having from 1 to 6 carbons, alternatively an OH group, a methoxy group or an ethoxy group, alternatively a methoxy group or an ethoxy group.
  • Substituent Y 1 is an alkyl group containing from 1 to 8 carbons, alternatively 1 to 6 carbons, alternatively 1 to 4 carbons.
  • the (R 10 ) m (Y 1 ) 3-m –Si groups may be selected from - (Y 1 ) SiOH 2 , - (Y 1 ) 2 SiOH, -Y 1 Si (OR b ) 2 , -Si (OR b ) 3 , - (Y 1 ) 2 SiOR b with R b being an alkyl group having from 1 to 8 carbons.
  • silyl modified organic polymer (a) is an alkoxy silyl terminated polyether as previously described
  • the polymer backbone is exemplified in the structure above as
  • p is an integer from 2 to 4 inclusive and y is an integer ⁇ 4 i.e. of at least four.
  • An example might be a polyether having the following repeating groups, for example,
  • the number average molecular weight (Mn) of each polyether may range from about 300 to about 10,000 which may be determined by way of ASTM D5296-05 and calculated as polystyrene molecular weight equivalents.
  • the oxyalkylene units are not necessarily identical throughout the polyoxyalkylene but can differ from unit to unit.
  • a polyoxyalkylene for example, can comprise oxyethylene units (-C 2 H 4 -O-) , oxypropylene units (-C 3 H 6 -O-) or oxybutylene units (-C 4 H 8 -O-) , or mixtures thereof.
  • the polyoxyalkylene polymeric backbone consists essentially of oxyethylene units or oxypropylene units.
  • Polyoxyalkylenes usually have terminal hydroxyl groups and can readily be modified with moisture curable silyl groups, for example by reaction with an excess of an alkyltrialkoxysilane to introduce terminal alkyldialkoxysilyl groups as previously discussed. Alternatively, polymerization may occur via a hydrosilylation type process. Polyoxyalkylenes consisting wholly or mainly of oxypropylene units have properties suitable for many sealant and/or adhesive applications.
  • polyoxyalkylenes may include for example: units of the structure:
  • each R e is the same or different and is a divalent hydrocarbon group having 2 to 8 carbon atoms
  • each R f is the same or different and is an ethylene group or propylene group
  • each R g is the same or different and is a hydrogen atom or methyl group and each of the subscripts h and q1 is a positive integer in the range from 3 to 30.
  • Component (f) is added into the composition in an amount of It in an amount of from 0.5 to 3wt. %of the composition.
  • a known solution to improve the height to width ratio of a formed-in-place foam gasket is to increase the amount of thixotropic agent (component (e) herein) e.g. silica or calcium carbonate in the composition from which it is made but whilst increasing the height to width ratio of the formed-in-place foam gasket increasing the level of silica and calcium carbonate in the composition has the negative effects mentioned above.
  • the height to width ratio of a formed-in-place foam gasket (FIPFG) may be increased by maintaining a relatively low level of thixotropic agent (component (e) e.g. 5 or less wt. %of the composition but introducing an amount of a component (f) into the composition. It was seen that the thixotropy of the curable and foamable silicone composition was significantly increased with small amount of component (f) in combination with component (e) .
  • the composition may optionally further comprise additional ingredients or components (or “additives” ) , especially if the ingredient or component does not prevent the composition from curing and/or foaming.
  • additional ingredients include, but are not limited to, resins, surfactants; stabilizers; adhesion promoters; colorants, including dyes and pigments; anti-oxidants; carrier vehicles; heat stabilizers; flame retardants; flow control additives; inhibitors; non-reinforcing (sometimes referred to as extending) fillers.
  • One or more of the additives can be present as any suitable weight percent (wt. %) of the composition, such as about 0.1 wt. %to about 15 wt. %, about 0.5 wt. %to about 5 wt. %, or about 0.1 wt. %or less, about 1 wt. %, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or about 15 wt. %or more of the composition.
  • wt. % weight percent
  • One of skill in the art can readily determine a suitable amount of additive depending, for example, on the type of additive and the desired outcome. Certain optional additives are described in greater detail below.
  • the composition may further comprise an organopolysiloxane resin ( “resin” ) as a resin foam stabilizer.
  • the resin has a branched or a three-dimensional network molecular structure.
  • the resinous organopolysiloxane may be in a liquid or in a solid form, optionally dispersed in a carrier, which may solubilize and/or disperse the resin therein.
  • the resinous organopolysiloxane may be exemplified by an organopolysiloxane that comprises only T units, an organopolysiloxane that comprises T units in combination with other siloxy units (e.g. M, D, and/or Q siloxy units) , or an organopolysiloxane comprising Q units in combination with other siloxy units (i.e., M, D, and/or T siloxy units) .
  • the resin comprises T and/or Q units.
  • Specific examples are vinyl-terminated silsesquioxanes or MQ resins.
  • the resin may be formed from multiple groups of formula:
  • each R 5 is a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms, for example, alkyl groups such as methyl, ethyl, propyl, hexyl, octyl, dodecyl, tetradecyl, hexadecyl, and octadecyl, or an aromatic group having 6 to 20 carbons such as benzyl and phenylethyl groups and wherein each f" is from 0 to 4. If the resin is a T resin, then most groups have f" as 1 and if the resin is an MQ resin to largely comprises groups where f" is 0 (Q groups) or 4 (M groups) as previously discussed.
  • alkyl groups such as methyl, ethyl, propyl, hexyl, octyl, dodecyl, tetradecyl, hexadecyl, and octade
  • Suitable pigments may include carbon black, e.g. acetylene black, titanium dioxide, chromium oxide, zinc oxide, bismuth vanadium oxide, iron oxides and mixtures thereof.
  • the composition may additionally include one or more non-reinforcing fillers.
  • non-reinforcing fillers include crushed quartz, diatomaceous earths, barium sulphate, iron oxide, titanium dioxide and carbon black, talc, and wollastonite.
  • Other fillers which might be used alone or in addition to the above include carbon nanotubes, e.g. multiwall carbon nanotubes aluminite, hollow glass spheres, calcium sulphate (anhydrite) , gypsum, calcium sulphate, magnesium carbonate, e.g.
  • hydromagnesite a hydrated magnesium carbonate mineral having the formula Mg 5 (CO 3 ) 4 (OH) 2 ⁇ 4H 2 O; clays such as kaolin, aluminum trihydroxide, magnesium hydroxide (brucite) , graphite, copper carbonate, e.g. malachite, nickel carbonate, e.g. zarachite, barium carbonate, e.g. witherite and/or strontium carbonate e.g. strontianite.
  • Further alternative fillers include aluminum oxide, silicates from the group consisting of olivine group; garnet group; aluminosilicates; ring silicates; chain silicates; and sheet silicates.
  • the composition includes at least one filler comprising hollow particles, e.g. hollow spheres.
  • fillers can be useful for contributing to porosity and/or overall void fraction of the foam and can provide other advantages such as fire retardancy.
  • non-reinforcing fillers are therefore preferred over e.g. silica reinforcing fillers, if fillers are required in large amounts in the composition because the reinforcing fillers create the issues discussed above.
  • the non-reinforcing fillers when present and /or component (e) , may optionally be surface treated with a treating agent.
  • the treating agents used may be selected from one or more of, for example, organosilanes, polydiorganosiloxanes, or organosilazanes, hexaalkyl disilazane, short chain siloxane diols, a fatty acid or a fatty acid ester such as a stearate to render one or more of the filler (s) hydrophobic and therefore easier to handle and obtain a homogeneous mixture with the other components.
  • liquid hydroxyl-terminated polydiorganosiloxane containing an average from 2 to 20 repeating units of diorganosiloxane in each molecule which may optionally contain fluoro groups and or fluoro containing groups, if desired, hexaorganodisiloxane, hexaorganodisilazane, and the like.
  • a small amount of water can be added together with the silica treating agent (s) as processing aid.
  • the surface treatment of the fumed silica makes them easily wetted by polymers (a) .
  • the composition as described herein may further comprise a hydrosilylation reaction inhibitor to inhibit the cure of the composition.
  • Hydrosilylation reaction inhibitors are used, when required, to prevent or delay the hydrosilylation reaction curing process especially during storage.
  • the optional hydrosilylation reaction inhibitors of platinum based catalysts are well known in the art and include hydrazines, triazoles, phosphines, mercaptans, organic nitrogen compounds, acetylenic alcohols, silylated acetylenic alcohols, maleates, fumarates, ethylenically or aromatically unsaturated amides, ethylenically unsaturated isocyanates, olefinic siloxanes, unsaturated hydrocarbon monoesters and diesters, conjugated ene-ynes, such as 3-methyl-3-penten-1-yne, 3, 5-dimethyl-3-hexen-1-yne hydroperoxides, nitriles, and diaziridines.
  • Alkenyl-substituted siloxanes as described in US3989667 may be used, of which cyclic methylvinylsiloxanes such as 1, 3, 5, 7-tetramethyl-1, 3, 5, 7-tetravinylcyclotetrasiloxane, 1, 3, 5, 7-tetramethyl-1, 3, 5, 7-tetrahexenylcyclotetrasiloxane, are preferred.
  • One class of known hydrosilylation reaction inhibitor includes the acetylenic compounds disclosed in US3445420.
  • 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 3-methyl-1-butyn-3-ol, 1-ethynyl-1-cyclohexanol (ETCH) , 2-methyl-3-butyn-2-ol, 3-butyn-1-ol, 3-butyn-2-ol, propargyl alcohol, 1-phenyl-2-propyn-1-ol, 3, 5-dimethyl-1-hexyn-3-ol, 3-phenyl-1-butyn-3-ol, 1-ethynylcyclopentanol, 3-methyl-1-penten-4-yn-3-ol, and mixtures thereof.
  • Derivatives of acetylenic alcohol may include those compounds having at least one silicon atom.
  • inhibitor concentrations as low as 1 mole of inhibitor per mole of the metal of catalyst 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 are required.
  • the optimum concentration for a given inhibitor in a given composition is readily determined by routine experimentation. 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 0.0125 to 10 wt. %of the composition.
  • the composition further comprises an adhesion promoter.
  • the adhesion promoter can improve adhesion of the foam to a substrate being contacted during curing.
  • the adhesion promoter is selected from organosilicon compounds having at least one alkoxy group bonded to a silicon atom in a molecule. This alkoxy group is exemplified by a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a methoxyethoxy group.
  • non-alkoxy groups bonded to a silicon atom of this organosilicon compound are exemplified by substituted or non-substituted monovalent hydrocarbon groups such as alkyl groups, alkenyl groups, aryl groups, aralkyl groups, halogenated alkyl groups and the like; epoxy group-containing monovalent organic groups such as a 3-glycidoxypropyl group, a 4-glycidoxybutyl group, or similar glycidoxyalkyl groups; a 2- (3, 4-epoxycyclohexyl) ethyl group, a 3- (3, 4-epoxycyclohexyl) propyl group, or similar epoxycyclohexylalkyl groups; and a 4-oxiranylbutyl group, an 8-oxiranyloctyl group, or similar oxiranylalkyl groups; acrylic group-containing monovalent organic groups such as a 3-methacryloxypropyl group and the like; and a hydrogen atom
  • This organosilicon compound generally has a silicon-bonded alkenyl group or silicon-bonded hydrogen atom. Moreover, due to the ability to impart good adhesion with respect to various types of substrates, this organosilicon compound generally has at least one epoxy group-containing monovalent organic group in a molecule.
  • This type of organosilicon compound is exemplified by organosilane compounds, organosiloxane oligomers and alkyl silicates. Molecular structure of the organosiloxane oligomer or alkyl silicate is exemplified by a linear chain structure, partially branched linear chain structure, branched chain structure, ring-shaped structure, and net-shaped structure.
  • a linear chain structure, branched chain structure, and net-shaped structure are typical.
  • This type of organosilicon compound is exemplified by silane compounds such as 3-glycidoxypropyltrimethoxysilane, 2- (3, 4-epoxycyclohexyl) -ethyltrimethoxysilane, 3-methacryloxy propyltrimethoxysilane, and the like; siloxane compounds having at least one silicon-bonded alkenyl group or silicon-bonded hydrogen atom, and at least one silicon-bonded alkoxy group in a molecule; mixtures of a silane compound or siloxane compound having at least one silicon-bonded alkoxy group and a siloxane compound having at least one silicon-bonded hydroxyl group and at least one silicon-bonded alkenyl group in the molecule; and methyl polysilicate, ethyl polysilicate, and epoxy group-containing ethyl polysilicate.
  • the content of the adhesion promoter in the composition is not particularly limited. In certain embodiments, the content of the adhesion-imparting agent is from about 0.01 to about 10 parts by mass per 100 parts total mass of components (a) and (b) .
  • the curable and foamable silicone compositions as described herein produce open cell and/or closed cell foams.
  • the density may be measured by any suitable method such as via the Archimedes principle, using a balance and density kit, and following standard instructions associated therewith.
  • a suitable balance is a Mettler-Toledo XS205DU balance with density kit.
  • a closed cell foam it may have a density of from 0.01 grams per cubic centimeter g/cm 3 to 5 g/cm 3 , alternatively from 0.05 g/cm 3 to 2.5 g/cm 3 alternatively from 0.1 g/cm 3 to 2.0 g/cm 3 , alternatively from 0.1 g/cm 3 to 1.5 g/cm 3 .
  • the foam may be too heavy or stiff for certain applications. If density is too low, the foam may lack desired structural integrity for certain applications.
  • the average pore size can be determined via any suitable method such as in accordance with ATSM method D3576-15 optionally with the following modifications:
  • the curable and foamable silicone compositions as described herein generally has pores that are uniform in size and/or shape.
  • the foam has an average pore size of between 0.001mm and 5mm, alternatively between 0.001mm and 2.5mm, alternatively between 0.001mm and 1mm, alternatively between 0.001mm and 0.5mm, alternatively between 0.001mm and 0.25mm, alternatively between 0.001mm and 0.1mm, and alternatively between 0.001mm and 0.05mm.
  • the height to width ratio of FIPFGs made using the curable and foamable silicone compositions as described herein is at least 0.625: 1.
  • This can be measured using any suitable method, for example a sample of cured foam strip can be cut into two parts and then the cross-sectional height and width can be measured using suitable digital calipers, such as Mitutoyo Absolute calipers which have an accuracy of 0.01mm from Mitutoyo America Corporation of Aurora, Illinois, USA.
  • the curable and foamable silicone compositions as described herein are usually stored in two parts to avoid premature cure.
  • the two parts are generally referred to as part A and part B.
  • Two-part compositions are utilised so that that components (a) polymer, (b) cross-linker, (c) blowing agent and (d) catalyst are not all stored together.
  • Part A may comprise components (a) , (c) and (d) and Part B comprises at least components (a) and (b) with part A free of component (b) cross-linker and part B free of component (d) catalyst.
  • each of the other optional components of the composition can be in either or both part A and part B or if desired may be introduced in one or more additional parts separate from the two parts (such that the system may be a three-or more part system) .
  • the thixotropic agent (e) and co-thixotropic agent (f) are stored in the part B composition with component (b) the cross-linker.
  • the two-part composition may be designed to be mixed together in any suitable ratio dependent on the content and concentration of the ingredients present in each part, for example the two part composition may be mixed in a Part A : Part B weight ratio of from 15: 1 to 1: 1.
  • the part A composition may include the ingredients in Table 1a and the part B composition may comprise the ingredients in Table 1b for a composition where the part A composition and part B composition are to be mixed together in a 1: 1 weight ratio. It will be appreciated that the total composition in weight % (wt. %) for any composition is 100 wt. %.
  • the curable and foamable silicone compositions may be prepared and supplied to form the silicone foam elastomer formed-in-place foam gaskets (FIPFGs) by any suitable method.
  • FIPFGs silicone foam elastomer formed-in-place foam gaskets
  • the method may for example comprise the following steps:
  • step (ii) transporting the foam prepared in step (i) to a suitable applicator
  • step (i) of the above process the ingredients of the part A composition are blended together and separately the ingredients of the part B composition are also blended together to form respective part A and part B compositions.
  • the part A composition might include, for the sake of example, one or more polymers in accordance with component (a) as hereinbefore described, components (c) and (d) and optionally a portion of the thixotropic agent (e) .
  • the part A composition might also include one or more of the aforementioned optional components such as inhibitor, non-reinforcing fillers, pigments or colorants and/or an MQ resin foam stabilizer.
  • the part B blend composition might include, for the sake of example, one or more polymers in accordance with component (a) as hereinbefore described, components (b) , (f) and the remainder of component (e) one or more of the aforementioned optional components such as pigments or colorants and/or an MQ resin foam stabilizer.
  • step (i) the part A composition and part B compositions are mixed to form a foam of the curable and foamable silicone composition described above.
  • Any suitable mixer may be used, for example the mixer may be a static mixer or a stirred tank or the like suitable for undertaking thorough mixing of the respective blend compositions.
  • the mixing container is temperature controllable such that the part A composition and part B compositions being mixed can be maintained within a desired temperature range.
  • step (ii) the foam produced in step (i) is transported to a suitable applicator.
  • a suitable applicator This may be by a pump to control the cell size of the silicone elastomer foam generated herein.
  • the applicator is a pre-programmed or programable robot applicator which can be used to apply the composition to the target substrate surface which may be planar or but more likely is provided with a groove into which the foam is introduced.
  • the composition should be applied in an amount that provides a satisfactorily performing gasket whilst minimising waste.
  • the applicator will be programed to apply an optimized amount of foam at a pre-determined dispensing flow rate such that the gaskets are applied as and where required and then allowed to cure in place. If desired heating may be applied to the gasket to assist in the cure thereof.
  • each blend/composition of part A, part B and the resulting combination thereof can have a wide viscosity range dependent on the ingredients used.
  • the composition has a viscosity of from 1,000 to 100,000 mPa. s, alternatively from 1,000 to 50,000 mPa. s, alternatively from 1,000 to 25,000 mPa.
  • the viscosity may be determined using any suitable method understood in the art, for example, using a rotational viscometer with spindle LV-4 (designed for viscosities in the range between 1,000-2,000,000mPa. s) or a rotational viscometer with spindle LV-1 (designed for viscosities in the range between 15 -20,000mPa. s) for viscosities less than 1000mPa. s and adapting the speed according to the polymer viscosity.
  • compositions described herein foam and cure when mixed at room temperature and humidity but heating may be used to accelerate cure if desired.
  • the gasket may undergo post-curing. Post-curing can be utilised to stabilize the performance of cured gasket in a short time e.g. 30 minutes to 3 hours, e.g. 1 hour.
  • An additional advantage which has been identified in the disclosure herein is the ability to use the curable and foamable silicone compositions described as a means for repairing preformed gaskets in case of damage or malfunction. Previously it was considered that gaskets of the type described herein were not repairable but this assumption has been shown to be incorrect when using the compositions herein as a foam gasket with the composition being dispensed on a lower substrate, cured and then a cover or upper substrate being placed on top and if necessary locked in place.
  • gaskets made from the curable and foamable silicone compositions as described herein adhered well to a variety of substrates and it is believed the use of the co-thixotropic agent (f) enhanced this feature when present in combination with component (e) .
  • Suitable substrates include aluminum, stainless steel, concrete and sheet moulding composite (SMC) , a glass-fibre reinforced polyester material.
  • the FIPFGs, compositions, foams, and methods of this disclosure are useful to form applications such as acting as a barrier to prevent absorption or penetration of air, dust, noise, liquids, gaseous substances, or dirt.
  • the gaskets are ideal for sound dampening, vibration dampening, shock-absorbing elements moisture protection, chemical protection, and air sealing. Examples of suitable applications include automotive gasket applications e.g.
  • gaskets for electric vehicle (EV) battery packs for electric vehicle (EV) battery packs, EV battery, Control units in EVs, lamp housings, fuse boxes, air filters, oil pan gaskets, oil seal case gaskets, oil screen gaskets, timing belt cover upper gaskets, timing rocker cover lower gaskets; gaskets for electrical appliances such as waterproof connectors, air conditioners, lighting devices, electronic components, housings, preferably control cabinets, lamps, drums (packaging) or filter housings, attached by foaming to a substrate in situ as described herein.
  • Other applications include external waterproofing applications.
  • compositions, foams, and methods are intended to illustrate and not to limit the invention.
  • compositions were generated utilizing different types and amounts of components. These are detailed below. All amounts are in wt. %unless indicated otherwise. As discussed above all viscosities are measured at 25°C.
  • the viscosity of individual ingredients may be determined by any suitable method such as using a rotational viscometer with spindle LV-4 (designed for viscosities in the range between 1,000-2,000,000mPa. s) or a rotational viscometer with spindle LV-1 (designed for viscosities in the range between 15 -20,000mPa. s) for viscosities less than 1000mPa. s and adapting the speed according to the polymer viscosity.
  • the alkenyl and/or alkynyl content of polymers as well as the silicon-bonded hydrogen (Si-H) content and/or silanol content of ingredients was determined using quantitative infra-red analysis in accordance with ASTM E168.
  • the BET values were either supplier data or measured in accordance with ISO 9277: 2010.
  • the hydromagnesite non-reinforcing filler used is sold commercially as UltraCarb TM C5-25 from LKAB Minerals AB of Lulea Sweden.
  • compositions of Ex. 1 to 5 are provided in Table 3a and the compositions of comparative examples 1-5 (C1-C5) are provided in Table 3b.
  • Silica 2 is Fumed Silica treated with dimethyldichlorosilane having an average specific surface area (BET) of between 150 and190 m 2 /g;
  • BET average specific surface area
  • x-linker is used for all Examples and comparatives and is a trimethyl terminated methyl hydrogen polysiloxane having a viscosity of about 30mPa. s at 25°C;
  • Co-T A 1 is a trimethoxysilyl terminated polyether having a viscosity of 46Pa. s (supplier’s data) sold commercially by Kaneka under the name KANEKA SAX520;
  • Co-T A 2 is a trimethoxysilyl terminated polyether having a viscosity of 46Pa. s (supplier’s data) sold commercially by Kaneka under the name KANEKA SAX510
  • Co-T A 3 is a trimethoxysilyl terminated polyether having a viscosity 30,000mPa. s sold by Risun Polymer Co., Ltd. As RISUN 30000T.
  • Polymer 1, silica 1, silica 2 and x-linker are as described above.
  • Co-T A 4 is a trimethoxydimethyldisiloxane ethylene terminated polydimethylsiloxane having a viscosity of 400mPa. s at 25°C ;
  • Co-T A 5 is a Dimethyl (polyether) terminated polydimethylsiloxane having a viscosity of 305mPa. s;
  • Co-T A 6 is a trimethylsiloxy-endblocked dimethylmethyl (polyether) siloxane copolymer having a viscosity of 10,000mPa. s at 25°C.
  • Table 4a Viscosity (Pa. s) of part B compositions of Examples Shear rate 0.1/s
  • Table 4b Viscosity (Pa. s) of part B compositions of Comparative Examples Shear rate 0.1/s
  • compositions were then prepared.
  • the part A composition was mixed with the part B composition on a 1: 1 weight ratio.
  • a foam developed and was transported to the applicator for application on to a substrate surface to make a FIPFG” (Formed in Place Foam Gasket) as and where required.
  • Density (kg/m 3 ) was measured by cutting the cured foam into a regular cubic shape and determined the density by measuring the weight and volume.
  • Hardness (Shore 00) was measured following ASTM D2240-15e1.
  • the part A and part B mixture was in a string and waited it to be completely foamed.
  • the height and width of the foam was measured using Mitutoyo Absolute calipers having an accuracy of 0.01mm from Mitutoyo America Corporation of Aurora, Illinois, USA and the height to width ratio was calculated for the cured specimens.
  • Part A and B compositions were mixed in a 1: 1 weight ratio as previously described and a sufficient amount of each mixture was dispensed on
  • the strips of foamed silicone were then cured on the substrate surface.
  • the dispensed strips were left on the respective substrate to foam for 5 minutes at room temperature and then were post-cured in an oven at 100 °C for 1 h.
  • Adhesive failure refers to the situation when the coating detaches cleanly (peels off) from the substrate (poor adhesion) .
  • Compression set testing was undertaken in accordance with ASTM D395, Test Method B. Three tests were undertaken: (i) in a first the specimens were compressed to 50%of their original thickness and placed in an oven at 85°C for 1 week;

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

La présente invention concerne des compositions de silicone durcissables et expansibles, des élastomères de mousse de silicone fabriqués à l'aide desdites compositions, et des procédés de fabrication desdits élastomères expansés de silicone sous la forme de joints en mousse formés sur place (FIPFG) en élastomère de mousse de silicone. L'invention concerne l'utilisation d'un agent co-thixotrope (f) comprenant un ou plusieurs polyéthers modifiés par un silyle en une quantité de 0,5 à 3 % en poids de la composition, outre un agent thixotrope standard (e) par exemple de la silice, du carbonate de calcium, du talc ou un mélange de ceux-ci en une quantité de 2 à 5 % en poids de la composition qui, en combinaison, fournissent une augmentation significative de la thixotropie de la composition avant le durcissement.
PCT/CN2020/119143 2020-09-30 2020-09-30 Élastomères de mousse de silicone et leurs utilisations WO2022067597A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/CN2020/119143 WO2022067597A1 (fr) 2020-09-30 2020-09-30 Élastomères de mousse de silicone et leurs utilisations
CN202080103608.0A CN115989273A (zh) 2020-09-30 2020-09-30 有机硅泡沫弹性体及其用途

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2020/119143 WO2022067597A1 (fr) 2020-09-30 2020-09-30 Élastomères de mousse de silicone et leurs utilisations

Publications (1)

Publication Number Publication Date
WO2022067597A1 true WO2022067597A1 (fr) 2022-04-07

Family

ID=80951033

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2020/119143 WO2022067597A1 (fr) 2020-09-30 2020-09-30 Élastomères de mousse de silicone et leurs utilisations

Country Status (2)

Country Link
CN (1) CN115989273A (fr)
WO (1) WO2022067597A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115141491A (zh) * 2022-06-28 2022-10-04 中国工程物理研究院化工材料研究所 适用于直写3d打印的多组份硅胶、混合装置及打印方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005019343A1 (fr) * 2003-08-14 2005-03-03 Dow Corning Corporation Silicones presentant des proprietes de surface ameliorees et compositions de silicone durcissables pour preparer ces silicones
WO2006106360A1 (fr) * 2005-04-06 2006-10-12 Dow Corning Corporation Compositions d'organosiloxane
WO2008002532A1 (fr) * 2006-06-26 2008-01-03 Dow Corning Corporation Préparation d'élastomères de caoutchouc silicone

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005019343A1 (fr) * 2003-08-14 2005-03-03 Dow Corning Corporation Silicones presentant des proprietes de surface ameliorees et compositions de silicone durcissables pour preparer ces silicones
WO2006106360A1 (fr) * 2005-04-06 2006-10-12 Dow Corning Corporation Compositions d'organosiloxane
WO2008002532A1 (fr) * 2006-06-26 2008-01-03 Dow Corning Corporation Préparation d'élastomères de caoutchouc silicone

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115141491A (zh) * 2022-06-28 2022-10-04 中国工程物理研究院化工材料研究所 适用于直写3d打印的多组份硅胶、混合装置及打印方法

Also Published As

Publication number Publication date
CN115989273A (zh) 2023-04-18

Similar Documents

Publication Publication Date Title
KR102385489B1 (ko) 경화성 오르가노폴리실록산 조성물 및 전기·전자 부품의 보호제 또는 접착제 조성물
US11339266B2 (en) Composition, foamed silicone elastomer formed therefrom, and methods of formation
EP3225662B1 (fr) Composition de silicone durcissable par addition à un seul constituant, procédé permettant de stocker ladite composition, et procédé pour son durcissement
KR102322935B1 (ko) 접착 촉진제 및 그것을 함유하여 이루어지는 경화성 오르가노폴리실록산 조성물
JP2008074882A (ja) シリコーンゴム用２液付加反応硬化型接着剤
EP3666828A1 (fr) Composition de silicone durcissable par addition et caoutchouc de silicone durci
JP5030915B2 (ja) 被覆用シリコーン組成物及びその硬化被膜により被覆された被覆膜
EP2880081A1 (fr) Composition de caoutchouc silicone liquide durcissable en deux parties
WO2022067597A1 (fr) Élastomères de mousse de silicone et leurs utilisations
JP5060165B2 (ja) 低透湿性ポリオルガノシロキサン組成物
EP3986968A1 (fr) Composition se silicone thermoconductrice
JP2015199851A (ja) 電気・電子部品の保護剤または接着剤組成物
JPH06107950A (ja) 加熱硬化性オルガノポリシロキサン組成物
JP2005060549A (ja) 定型接着剤
JP6108015B2 (ja) シリコーンゴム硬化物のモジュラスを低減する方法、及びシリコーンゴム組成物
JP2015017198A (ja) シリコーンゴム硬化物のモジュラスを低減する方法、シリコーンゴム組成物及び硬化物
JP4083887B2 (ja) 加熱硬化型発泡性オルガノポリシロキサン組成物およびその硬化方法
JP7409339B2 (ja) 機械発泡用硬化性液状シリコーンゴム発泡体組成物及びシリコーンゴム発泡体の製造方法
JP2008150403A (ja) 硬化性組成物、及びその架橋ゴム
CN114630879A (zh) 聚苯硫醚树脂粘接用聚有机硅氧烷组合物
EP4352164A1 (fr) Compositions de caoutchouc de silicone durcissable
JP2006077262A (ja) 加熱硬化型発泡性オルガノポリシロキサン組成物およびその硬化方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20955622

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 20955622

Country of ref document: EP

Kind code of ref document: A1