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
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/14—Peroxides
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
  • H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
  • H01B3/30—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes
  • H01B3/46—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes silicones
• • 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
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
  • C08K3/20—Oxides; Hydroxides
  • C08K3/22—Oxides; Hydroxides of metals
  • C08K2003/221—Oxides; Hydroxides of metals of rare earth metal
  • C08K2003/2213—Oxides; Hydroxides of metals of rare earth metal of cerium
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/34—Silicon-containing compounds
  • C08K3/36—Silica
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
  • C08K5/005—Stabilisers against oxidation, heat, light, ozone
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2203/00—Applications
  • C08L2203/20—Applications use in electrical or conductive gadgets
  • C08L2203/206—Applications use in electrical or conductive gadgets use in coating or encapsulating of electronic parts

Definitions

• Crosslinkable silicone elastomer composition comprising a heat resistance additive
• the present invention relates to a crosslinkable silicone elastomer composition comprising a heat resistance additive.
• the invention relates to a crosslinkable silicone elastomer composition comprising a heat resistance additive which is cerium (IV) neodecanoate.
• silicone elastomers have a very high inertia to heat and to cold in continuous service from -50° C. to 200° C. In this temperature range, they retain almost all of their chemical, mechanical and dielectric properties.
• silicone elastomers when silicone elastomers are used at a temperature above 200° C. for a long period, for example several days, their properties tend to degrade. It is therefore sometimes necessary to add suitable thermal resistance additives to their composition. This is all the more true when silicone elastomers are intended to be used in the production of envelopes or primary insulators used in the constitution of electric wires or cables protected against fire, which must withstand high temperatures. This is also true when silicone elastomers are intended for use in the production of automotive cables.
• antioxidant compounds are mainly of two types, either non-metallic (based on sulphur, phosphorus, amine, etc.), or inorgano- or organometallic.
• the antioxidants used do not always make it possible to obtain transparent silicone elastomers which can be easily colored. Moreover, it is sometimes necessary to formulate the antioxidants in a solvent in order to be able to add them to the crosslinked silicone composition in elastomer, which complicates the formulation of the silicone composition. The presence of antioxidants in the silicone composition can also slow down the crosslinking kinetics.
• the present invention aims to satisfy at least one of the following objectives.
• One of the essential objectives of the invention is to provide a crosslinkable silicone elastomer composition which makes it possible to obtain a thermally stable silicone elastomer.
• One of the essential objectives of the invention is to provide a crosslinkable silicone elastomer composition which makes it possible to obtain a silicone elastomer having good mechanical properties and thermal resistance, for example being able to withstand several days at more 250°C.
• One of the essential objectives of the invention is to provide a crosslinkable silicone elastomer composition which makes it possible to obtain a silicone elastomer which retains its elastomeric properties, even in the event of repeated and/or prolonged exposure to the heat.
• One of the essential objectives of the invention is to provide a crosslinkable silicone elastomer composition which makes it possible to obtain a silicone elastomer which retains good elongation properties after heat treatment, for example which retains elongation at break greater than 150%, or 200%, after heat treatment.
• One of the essential objectives of the invention is to provide a heat resistance additive that does not present solubility problems in silicone compositions, and which can be directly dispersed in silicone compositions, without using a solvent. .
• Another essential objective of the invention is to provide a silicone composition that can be crosslinked into elastomer which makes it possible to obtain a silicone elastomer which is transparent, and consequently which can be easily colored by adding pigment.
• Another essential object of the invention is to provide a silicone composition that can be crosslinked into elastomer which makes it possible to obtain a silicone elastomer which is transparent, even when the silicone composition comprises a large quantity of filler, for example more than 15% by weight.
• Another essential objective of the invention is to provide a silicone composition that can be crosslinked into elastomer which makes it possible to obtain a silicone elastomer having good mechanical properties and thermal resistance, the crosslinking kinetics of which are not slowed down.
• Another essential objective of the invention is to provide a crosslinkable silicone elastomer composition which can be used for the production of envelopes or primary insulators used in the constitution of electrical wires or cables.
• Another essential objective of the invention is to provide a crosslinkable silicone elastomer composition which can be used for the production of automobile cables.
• One of the essential objectives of the invention is to provide a crosslinkable silicone elastomer composition which is simple to formulate.
• a crosslinkable silicone X elastomer composition comprising: - At least one heat resistance additive D, which is cerium (IV) neodecanoate.
• thermo resistance additive D which is cerium (IV) neodecanoate makes it possible to improve the thermal resistance of the silicone elastomer, while keeping the transparency of the silicone elastomer, even when the silicone composition X comprises more than 15% by weight of filler E, or when the cerium content is high.
• the elastomer obtained is thermally stable. It has acceptable elastomeric properties and does not become brittle after treatment for 3 days at 300°C, 7 days at 275°C or 21 days at 250°C. Hardness, resilience, breaking strength, elongation at break and the 100% modulus remained within entirely acceptable limits, that is to say within limits allowing the intended use of the elastomer.
• the elastomer obtained is thermally stable even after a long-term heat treatment, for example 3000 hours at 200° C.
• This long-term heat treatment corresponds to the tests carried out on automotive cables (cf. ISO 6722 standard). It is therefore possible to use the silicone composition X that can be crosslinked into an elastomer to produce automobile cables and in particular automobile cables for electric or hybrid vehicles.
• cerium(IV) neodecanoate is liquid at room temperature, so it is easy to use and to mix. It is possible to add it to the silicone composition as it is, without solvent. The silicone composition is therefore easy to formulate.
• the silicone composition X makes it possible to obtain a silicone elastomer having good mechanical properties, and the use of cerium(IV) neodecanoate does not impact the crosslinking kinetics.
• the invention also relates to a silicone elastomer obtained by crosslinking composition X, preferably by heating to a temperature between 80° C. and 250° C.
• the invention also relates to an electric wire or electric cable comprising at least one conductive element 1 surrounded by at least one primary insulating layer 2 characterized in that said primary insulating layer 2 comprises a silicone elastomer obtained by crosslinking of composition X .
• the invention also relates to the use of a silicone composition X for the production of envelopes or primary insulators of single conductors used in the constitution of electrical wires or cables.
• the invention also relates to the use of a silicone composition X for producing automobile cables, in particular automobile cables for electric or hybrid vehicles.
• the invention also relates to a method for manufacturing an electric wire or electric cable comprising the following steps: i. forming around an electrical conductor 1 at least one primary insulating layer 2 which consists of a material obtained by crosslinking the silicone composition X, preferably by heating to a temperature between 80° C. and 250° C., ii. optionally, assembling at least two insulated electrical conductors as obtained in step i, and iii. optionally, extruding an outer sheath as defined above around the insulated electrical conductor(s) of step i or ii.
• thermally stable silicone elastomer in the sense of the invention, is meant in particular a silicone elastomer which retains elastomeric properties and does not become hard or brittle when subjected to a temperature above 200° C., in particular between 250° C. and 300° C., maintained for several days, in particular 3 days. Quite preferably, they are elastomers thus resistant to a temperature above 250° C., in particular between 275° C. and 300° C., maintained for 3 days or more.
• electrical wire is meant an electrotechnical component used to transport electricity, in order to transmit energy or information and which consists of an electrically conductive material, solid or multi-strand, surrounded by an insulating envelope.
• the inside of an electrical wire is called the “core” of the wire.
• conductor or “single conductor” is meant an element composed of a core and its insulating envelope.
• electrical cable is meant an electrotechnical component used to transport electricity, in order to transmit energy or information and which is made up of several electrically separate and mechanically integral conductors, possibly with an external shield. .
• An electric cable consists of one or more single conductor (s) (usually based on copper or aluminum); each of these single conductors is protected by an envelope or primary insulator made of one or more concentric layer(s) based on an insulator. Around this envelope or these envelopes (in the case of a cable with several single conductors) is (are) provided one or more filling element(s) and/or one or more reinforcing element(s) based in particular on glass fibers and/or mineral fibers. Then an outer sheath which may comprise one or more sheath(s) is most often present.
• the filling element(s) and/or the reinforcing element(s), which is (are) arranged around the single conductors (each equipped with its primary insulator), constitute(s) a common envelope for all the single conductors.
• crosslinkable silicone X elastomer composition according to the invention comprises:
• At least one heat resistance additive D which is cerium (IV) neodecanoate.
• Thermal resistance additive D The heat resistance additive D is cerium (IV) neodecanoate. Cerium is in oxidation state IV. Cerium (IV) neodecanoate has the following formula: CeC4oH76C>8,
• cerium (IV) neodecanoate is as follows:
• Neodecanoate is a mixture of isomers having the formula (C10H19O2) ' .
• the neodecanoate is a mixture of constitutional isomers, including trial kylacetates (ie the carbon in the alpha position of the carbonyl is a quaternary carbon).
• isomers of neodecanoate mention may be made of 2,2,3,5-tetramethylhexanoate, 2,4-dimethyl-2-isopropylpentanoate, 2,5-dimethyl-2-ethylhexanoate and 2,2-dimethyloctanoate.
• Cerium(IV) neodecanoate is liquid at room temperature and is dispersible in silicones. It can therefore be used pure or formulated. When it is used pure, it is added as it is to the silicone composition X. When it is formulated, it can be added to a silicone oil or to a silicone gum before being added to the silicone composition X.
• Cerium(IV) neodecanoate disperses well in silicones, it is directly compatible with silicones. It is therefore not necessary to use a solvent to incorporate it into the silicone composition.
• the silicone composition X has a cerium (IV) content of between 50 and 3000 ppm by weight, preferably between 50 and 1000 ppm, and preferably between 50 and 500 ppm.
• the silicone composition X has a cerium (IV) content of between 50 and 350 ppm, preferably between 60 and 300 ppm, preferably between 70 and 250 ppm, and even more preferably between 90 and 200 ppm.
• a cerium content of between 50 and 350 ppm makes it possible in particular to obtain an elastomer which retains an elongation at break greater than 200%, after heat treatment for 7 days at 275° C.
• Cerium (IV) neodecanoate makes it possible to obtain a thermally stable elastomer, which retains its elastomeric properties, and does not become hard or brittle when it is subjected to a temperature above 200° C., in particular between 250 ° C and 300° C, maintained for several days, in particular 3 days.
• Cerium (IV) neodecanoate makes it possible to obtain a thermally stable elastomer after heat treatment for 3 days at 300°C, 7 days at 275°C, 21 days at 250°C, or 3000 hours at 200°C .
• the elastomer obtained is transparent, even when the silicone composition X comprises a large amount of filler and/or a high cerium content. It is therefore possible to color it easily by adding pigments to the silicone composition X. Furthermore, it is also possible to have bright colors, since there is no alteration of the colors or of the transparency.
• cerium(IV) neodecanoate has a free acid content of less than 5%, preferably less than 2.5%, and preferably less than 1.5%.
• the free acid level corresponds to the level of uncomplexed free neodecanoic acid.
• the crosslinkable elastomeric silicone X composition can be presented in a single or more packaging (single- or multi-component). It comprises, in addition to the heat resistance additive D, a main constituent formed of one or more organopolysiloxane constituent(s), an appropriate catalyst and optionally one or more compound(s), preferably chosen from fillers, crosslinking inhibitors, and pigments.
• the silicone composition X can crosslink either at high temperature under the action of organic peroxides (EVC or HCR), or in the presence of a metal catalyst at room temperature, optionally in the presence of humidity (polyaddition RTV or polycondensation) or heat (EVC or polyaddition LSR).
• EVC organic peroxides
• RTV, LSR, EVC or HCR are well known to those skilled in the art: RTV is the abbreviation for “Room Temperature Vulcanizing”; LSR stands for “Liquid Silicone Rubber”; HCR is the abbreviation of "Heat Cured Rubber” and EVC is the abbreviation of "Hot Vulcanizable Elastomer”.
• the various ingredients can be intimately mixed using devices well known in the silicone elastomer industry, the order of incorporation possibly being arbitrary.
• the crosslinkable silicone composition X into elastomer is a crosslinking composition:
• the elastomeric crosslinkable silicone X composition further comprises:
• At least one organopolysiloxane A comprising, per molecule, at least 2 alkenyl groups having from 2 to 6 carbon atoms;
• At least one organopolysiloxane B comprising, per molecule, at least 2 hydrogenosilyl Si—H functions;
• the silicone composition X crosslinkable into elastomer comprises:
• At least one organopolysiloxane A comprising, per molecule, at least 2 alkenyl groups having from 2 to 6 carbon atoms;
• At least one organopolysiloxane B comprising, per molecule, at least 2 hydrogenosilyl Si—H functions;
• At least one heat resistance additive D which is cerium neodecanoate (IV).
• said silicone composition X having a cerium (IV) content of between 50 and 3000 ppm by weight.
• organopolysiloxane A is chosen from organopolysiloxane compounds comprising units of formula (I):
• the radicals Z which are identical or different, represent a linear or branched alkenyl radical, having from 2 to 6 carbon atoms;
• the radicals Z represent a vinyl radical.
• U can represent a monovalent radical chosen from the group consisting of alkyl groups having 1 to 8 carbon atoms, optionally substituted by at least one halogen atom such as chlorine or fluorine, cycloalkyl groups having 3 to 8 carbon atoms and aryl groups having 6 to 12 carbon atoms.
• U can advantageously be chosen from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl.
• Said organopolysiloxanes A can be oils with a dynamic viscosity of the order of 10 to 1,000,000 mPa.s at 25° C., generally of the order of 10 to 70,000 mPa.s at 25°C, or rubbers with a dynamic viscosity greater than 1,000,000 mPa.s at 25°C. Silicone oils and gums are polymers with a linear structure.
• organopolysiloxanes A can have a linear, branched or cyclic structure. Their degree of polymerization is preferably between 2 and 5000.
• the organopolysiloxane A has a linear structure.
• these essentially consist of "D" siloxyl units chosen from the group consisting of the Z2S1O2/2, ZUS1O2/2 and U2S1O2/2 siloxyl units, and of "M" siloxyl units chosen from the group consisting of the siloxyl units ZU2SiOi/2, Z2USiOi/2 and Z3S1O1/2.
• Z and U symbols are as described above.
• terminal “M” units mention may be made of the trimethylsiloxy, dimethylphenylsiloxy, dimethylvinylsiloxy or dimethylhexenylsiloxy groups.
• D units mention may be made of the dimethylsiloxy, methylphenylsiloxy, methylvinylsiloxy, methylbutenylsiloxy, methylhexenylsiloxy, methyldecenylsiloxy, diphenylsiloxy or methyldecadienylsiloxy groups.
• linear organopolysiloxanes which may be unsaturated compounds A according to the invention are:
• the cyclic organopolysiloxanes which can also be unsaturated compounds A according to the invention are, for example, those consisting of "D" siloxyl units of the following formulas: Z2S1O2/2, U2S1O2/2 or ZUS1O2/2, which can be of the type dialkylsiloxy, alkylarylsiloxy, alkylvinylsiloxy, alkylsiloxy.
• Said cyclic organopolysiloxanes have a viscosity of the order of 10 to 5000 mPa.s at 25°C.
• the organopolysiloxane compound A has a mass content of Si-vinyl unit of between 0.001 and 30%, preferably between 0.01 and 10%.
• silicone resins comprising at least one vinyl radical.
• they can be chosen from the group consisting of the following silicone resins:
• the organopolysiloxane A can be a mixture of several oils or resins meeting the definition of organopolysiloxane A.
• the organopolysiloxane A does not comprise any resin.
• the elastomeric crosslinkable silicone composition X comprises between 55 and 85% by weight of organopolysiloxane A, preferably between 60 and 80%, relative to the total weight of the silicone composition X.
• the organopolysiloxane A carrying alkenyl groups advantageously has a viscosity at 25° C. at most equal to 50,000 mPa.s and preferably between 200 and 10,000 mPa.s.
• the organopolysiloxane A bearing alkenyl groups advantageously has a viscosity at 25° C. of greater than 1000 mPa.s, preferably lying in the range from greater than 5,000 mPa.s to 300,000 mPa. s.
• the organopolysiloxane A bearing alkenyl groups advantageously has a viscosity at 25° C. greater than 300,000 mPa.s and, preferably, between 1 million mPa.s and 30 million mPa.s or even more.
• the silicone composition X that can be crosslinked to elastomer comprises at least one organopolysiloxane B comprising, per molecule, at least 2 hydrogenosilyl Si—H functions.
• the silicone composition X that can be crosslinked to elastomer comprises an organopolysiloxane B comprising, per molecule, at least 2 hydrogenosilyl functions Si—H, and a crosslinking catalyst C which is chosen from polyaddition catalysts.
• Compound B is an organohydrogenpolysiloxane compound comprising per molecule at least two and preferably at least three hydrogenosilyl (Si—H) functions.
• the organohydrogenpolysiloxane B can advantageously be an organopolysiloxane comprising at least one unit of formula (III):
• U can represent a monovalent radical chosen from the group consisting of alkyl groups having 1 to 8 carbon atoms, optionally substituted by at least one halogen atom such as chlorine or fluorine, cycloalkyl groups having 3 to 8 carbon atoms and aryl groups having 6 to 12 carbon atoms.
• U can advantageously be chosen from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl.
• organopolysiloxanes B can have a linear, branched or cyclic structure.
• the degree of polymerization is preferably greater than or equal to 2. Generally, it is less than 5000.
• the linear organopolysiloxanes can be oils with a dynamic viscosity of the order of 1 to 100000 mPa.s at 25°C and more generally of the order of 10 to 5000 mPa.s at 25°C.
• organopolysiloxanes which may be compounds B according to the invention comprising at least one hydrogen atom bonded to a silicon atom are:
• organohydrogenpolysiloxane compounds B [0088] [Chem 2]
• - 0 ⁇ a ⁇ 150 preferably 0 ⁇ a ⁇ 100, and more particularly 0 ⁇ a ⁇ 20, and - 1 ⁇ b ⁇ 90, preferably 10 ⁇ b ⁇ 80 and more particularly 30 ⁇ b ⁇ 70,
• the organohydrogenpolysiloxane compound B has a mass content of hydrogenosilyl Si—H functions of between 0.2 and 91%.
• the organohydrogenpolysiloxane compound B may have a mass content of hydrogenosilyl Si—H functions greater than or equal to 5%, preferably greater than or equal to 10%.
• the mass content of hydrogenosilyl Si—H functions is between 5 and 40%, or between 10 and 30%.
• the organohydrogenpolysiloxane B is a resin having a branched structure.
• the organohydrogenpolysiloxane B can be chosen from the group consisting of the following silicone resins:
• the organohydrogenpolysiloxane resin B is an M'Q or MD'Q resin as described above. Even more preferentially, the organohydrogenpolysiloxane resin B is an M'Q resin.
• the organohydrogenpolysiloxane B can be a mixture of several oils or resins meeting the definition of organohydrogenpolysiloxane B.
• the organohydrogenpolysiloxane B is not a resin.
• the elastomer-crosslinkable silicone composition X may comprise between 0 and 10% by weight of organohydrogenpolysiloxane B, preferably between 0.5 and 10%, relative to the total weight of the silicone composition X.
• the molar ratio of the hydrogenosilyl Si-H functions of the compounds B to the alkene functions of the compounds A is between 0.02 and 5, preferably between 0.1 and 4, and more preferably between 0, 5 and 3.
• the elastomeric crosslinkable silicone composition X comprises a crosslinking catalyst C.
• the elastomeric crosslinkable silicone composition X may comprise between 0.1 and 2% by weight of crosslinking catalyst C, relative to the total weight of the silicone composition X.
• the crosslinking catalyst C is an organic peroxide.
• the organic peroxide can be any of those which act as vulcanizing agents towards the compositions forming silicone elastomers. It may thus be any of the peroxides or per esters which are known to be used with silicone elastomers, for example di-tert-butyl peroxide, benzoyl peroxide, tert-butyl peracetate, tert-butyl peroxide, dicumyl, 2,5-dimethylhexane 2,5-diperbenzoate and bis(t-butylperoxy)-2,5-dimethyl-2,5 hexane, monochlorobenzoyl peroxide, 2-4-dichlorobenzoyl peroxide, bis peroxide (2,4-dichlorobenzoyl), tert-butyl peracetate, 2,5-dimethyl-2,5-cli(tert-butylperoxy) hexane, 2,2-bis (t- butylperoxy)-p-
• the organic peroxide is chosen from benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butyl peracetate, dicumyl peroxide, and mixtures thereof.
• the organic peroxide is chosen from the group consisting of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, dicumyl peroxide, bis(2,4-dichlorobenzoyl)peroxide ), and mixtures thereof.
• the amount of organic peroxide is between 0.05 and 10 parts by weight, preferably between 0.5 and 2 parts by weight, per 100 parts. by weight of the silicone composition X.
• the choice of peroxide will depend in practice on the process used to harden the elastomer (vulcanization process).
• the peroxide used is then preferably monochlorobenzoyl peroxide and/or 2,4-dichlorobenzoyl peroxide.
• the vulcanization process operates in the presence of pressure (for example, steam tube), the peroxide used is then preferably bis(t-butylperoxy)-2,5-dimethyl-2,5-hexane.
• catalyst C is a hydrosilylation reaction catalyst.
• the silicone composition X crosslinkable into elastomer comprises at least one organopolysiloxane B comprising, per molecule, at least 2 hydrogenosilyl Si—H functions, and preferably at least 3 hydrogenosilyl Si—H functions.
• Hydrosilylation reaction catalysts are well known.
• platinum and rhodium compounds are used. It is possible, in particular, to use the complexes of platinum and of an organic product described in patents US-A-3,159,601, US-A-3,159,602, US-A-3,220,972 and European patents EP-A- 0,057,459, EP A 0,188,978 and EP-A-0,190,530, the complexes of platinum and vinyl organosiloxanes described in patents US-A-3,419,593, US-A-3,715,334, US-A -3,377,432 and US-A-3,814,730.
• the generally preferred catalyst is platinum.
• the quantity by weight of catalyst C calculated by weight of platinum metal, is generally between 2 and 400 ppm, preferably between 5 and 200 ppm based on the total weight of the organopolysiloxane A.
• catalyst C can be a platinum catalyst, for example a Karstedt catalyst.
• the crosslinkable silicone composition X comprises a filler E.
• the filler E makes it possible to improve the mechanical properties of the silicone elastomer article obtained at the end of the crosslinking, while retaining good elastomeric properties.
• the filler E makes it possible to improve the modulus at break of the silicone elastomer article obtained, while maintaining a high elongation at break.
• the silicone composition X comprises between 15 and 35% by weight of filler E.
• the silicone composition X comprises between 20 and 30% by weight of filler E.
• the optionally provided filler E is preferably mineral.
• the filler E can be a very finely divided product whose mean particle diameter is less than 0.1 ⁇ m.
• the filler E may in particular be siliceous.
• siliceous materials they can play the role of reinforcing or semi-reinforcing filler.
• the reinforcing siliceous fillers are chosen from colloidal silicas, combustion and precipitation silica powders or mixtures thereof. These powders have an average particle size generally less than 0.1 ⁇ m (micrometers) and a BET specific surface greater than 30 m 2 /g, preferably between 30 and 350 m 2 /g.
• siliceous fillers such as diatomaceous earth or crushed quartz can also be used. These silicas can be incorporated as such or after having been treated with organosilicon compounds usually used for this purpose.
• organosilicon compounds usually used for this purpose.
• these compounds are methylpolysiloxanes such as hexamethyldisiloxane, octanethylcydotetrasiloxane, methylpolysilazanes such as hexamethyldisilazane, hexamethylcyclotrisilazane, tetramethyldivinyldisilazane, chlorosilanes such as dimethyldichlorosilane, trimethylchlorosilane, methylvinyldichlorosilane, dimethylvinylchlorosilane, alkoxysilanes such as dimethyldichlorosilane, methylvinyldichlorosilane, dimethylvinylchloro
• non-siliceous mineral materials can act as a semi-reinforcing mineral filler or filler.
• these non-siliceous fillers which can be used alone or as a mixture are calcium carbonate, optionally surface-treated with an organic acid or with an ester of an organic acid, calcined clay, titanium oxide of the rutile type, oxides of iron, zinc, chromium, zirconium, magnesium, different forms of alumina (hydrated or not), boron nitride, lithopone, barium metaborate, barium sulphate and microbeads of glass.
• These fillers are coarser with generally an average particle diameter greater than 0.1 ⁇ m and a specific surface generally less than 30 m 2 /g. These fillers may have been surface-modified by treatment with the various organosilicon compounds usually employed for this purpose.
• the filler E is silica, and even more preferably combustion silica.
• the silica has a BET specific surface of between 75 and 410 m 2 /g.
• the crosslinkable silicone X elastomer composition comprises:
• organopolysiloxane A comprising, per molecule, at least 2 alkenyl groups having from 2 to 6 carbon atoms
• organopolysiloxane B comprising, per molecule, at least 2 hydrogenosilyl Si—H functions
• At least one thermal resistance additive D which is cerium neodecanoate (IV).
• the silicone composition X that can be crosslinked into elastomer may also comprise a crosslinking inhibitor F. This is generally used to give the ready-to-use composition a certain pot life. ). These crosslinking inhibitors are present in particular when the silicone composition X precursor of silicone coating(s) is an organopolysiloxane which can be crosslinked by polyaddition or dehydrogenation and when the catalyst C used is based on platinum.
• the crosslinking inhibitor F is preferably chosen from acetylenic alcohols (ethynylcyclohexanol: ECH), diallylmaleates, triallylisocyanurates, dialkylmaleates (diethylmaleates or dialkylalcinyldicarboxylates) (diethylacetylene dicarboxylate) or even from organopolysiloxanes, advantageously cyclic and substituted with au least one alkenyl, tetramethylvinylcyclotetrasiloxane being particularly preferred, or alkylated maleates.
• Acetylenic alcohols are useful retarders according to the invention. Mention may be made, by way of examples: - ethynyl-1-cyclohexanol 1;
• the elastomeric crosslinkable silicone composition X may also comprise a pigment G.
• the pigment G may be an organic pigment or an inorganic pigment (mineral pigment).
• the silicone composition X that can be crosslinked into elastomer can also comprise a plasticizer H.
• the plasticizers H are generally organosilicon in nature and are introduced into the silicone composition in a proportion of 0 to 20 parts per 100 parts of organopolysiloxane A. They make it possible to prevent the compositions from hardening during storage.
• the plasticizers mention may be made of silanes containing hydrolysable groups, or hydroxylated or alkoxylated diorganopolysiloxane oils of low molecular weight. Such compositions are for example described in French patent 1,111,969.
• the crosslinkable silicone X elastomer composition consists of:
• At least one organopolysiloxane A comprising, per molecule, at least 2 alkenyl groups having from 2 to 6 carbon atoms;
• At least one organopolysiloxane B comprising, per molecule, at least 2 hydrogenosilyl Si—H functions;
• At least one heat resistance additive D which is cerium neodecanoate (IV);
• At least one pigment G At least one pigment G
• At least one plasticizer H At least one plasticizer H.
• the crosslinkable silicone X elastomer composition does not comprise an adhesion promoter.
• the crosslinkable silicone composition X to elastomer does not comprise a silicone resin, in particular, no silicone resin comprising at least one alkenyl radical.
• the crosslinkable silicone composition X into elastomer is crosslinkable in the presence of a metal catalyst at room temperature, in the presence of humidity (polycondensation RTV).
• the elastomeric crosslinkable silicone X composition further comprises:
• the organopolysiloxane A' can be linear or branched, it carries hydroxyl groups or hydrolysable groups chosen from the group consisting of alkoxy, alkoxy-alkylene-oxy, amino, amido, acylamino, aminoxy, iminoxy, ketiminoxy, acyloxy and enoxy, and preferably alkoxy, which crosslink at ambient temperature by polycondensation reactions, under the action of humidity.
• hydrolyzable and condensable groups Z of alkoxy type mention may be made of groups having from 1 to 8 carbon atoms such as methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, iso-butoxy , sec-butoxy, tert-butoxy, 2-methoxyethoxy, hexyloxy or octyloxy.
• hydrolyzable and condensable groups Z of the alkoxy-alkylene-oxy type mention may be made of the methoxy-ethylene-oxy group.
• hydrolyzable and condensable groups Z of amino type mention may be made of methylamino, dimethylamino, ethylamino, diethylamino, n-butylamino, sec-butylamino or cyclohexylamino groups.
• hydrolyzable and condensable groups Z of the amido type mention may be made of the N-methyl-acetamido group.
• hydrolyzable and condensable groups Z of acylamino type mention may be made of the benzoyl-amino group.
• hydrolyzable and condensable groups Z of the aminoxy type mention may be made of the dimethylaminoxy, diethylaminoxy, dioctylaminoxy or diphenylaminoxy groups.
• hydrolyzable and condensable groups Z of the iminoxy and in particular ketiminoxy type mention may be made of the groups derived from the following oximes: acetophenone-oxime, acetone-oxime, benzophenone-oxime, methyl-ethyl-ketoxime, di-isopropylketoxime or methyl isobutyl ketoxime.
• hydrolysable and condensable groups Z of acyloxy type mention may be made of the acetoxy group.
• hydrolyzable and condensable groups Z of the enoxy type mention may be made of the 2-propenoxy group.
• the organopolysiloxane A' may be a linear polydiorganosiloxane having at least two hydroxyl or alkoxy groups per molecule and whose dynamic viscosity at 25° C. is between 50 mPa.s and 50 x 10 6 mPa.s, of preferably between 50 mPa.s and 10 6 mPa.s in the case of silicone oils, or greater than 10 6 mPa.s in the case of silicone gums.
• the identical or different organic groups generally present in the structure of the organopolysiloxane A′ are the methyl, ethyl, phenyl or trifluoropropyl radicals.
• at least 80% by number of said organic groups are methyl groups bonded directly to silicon atoms.
• more especially preferred are a, co-bis (dimethylhydroxysilyl) polydimethylsiloxanes and a, co-bis (dimethylalkoxysilyl) polydimethylsiloxanes
• the elastomeric crosslinkable silicone composition X comprises between 40 and 90% by weight of organopolysiloxane A′, preferably between 50 and 80%, relative to the total weight of the silicone composition X.
• the catalyst C' is a catalyst for polycondensation reactions.
• Polycondensation catalysts are widely known to those skilled in the art.
• catalyst C′ may, inter alia, be chosen from compounds based on tin or titanium widely known to those skilled in the art or from organic catalysts such as the guanidines described in patent applications EP2268743 and EP2367867 or from metal complexes, for example based on Zn, Mo, Mg, etc. described in patent applications EP2222626, EP2222756, EP2222773, EP2935489, EP2935490 and WO2015/082837.
• the elastomer-crosslinkable silicone composition X may comprise between 0.1 and 2% by weight of catalyst C′, relative to the total weight of the silicone composition X.
• the crosslinking agent B′ is preferably an organosilicon compound bearing per molecule more than two hydrolysable groups bonded to the silicon atoms. Such crosslinking agents are well known to those skilled in the art and are commercially available.
• the crosslinking agent B' is preferably a silicon compound, each molecule of which comprises at least three hydrolysable and condensable groups chosen from the group consisting of: alkoxy, alkoxy-alkylene-oxy, amino, amido, acylamino, aminoxy , iminoxy, ketiminoxy, acyloxy and enoxy, and preferably alkoxy. These groups are as defined previously.
• the elastomeric crosslinkable silicone composition X may comprise between 1 and 20% by weight of crosslinking organosilicon compound B′, preferably between 2 and 15%, relative to the total weight of the silicone composition X.
• the filler E and the pigment G are as defined previously.
• the crosslinkable silicone composition X into elastomer comprises between 10 and 40% by weight of filler E, preferably between 15 and 35%, relative to the total weight of the silicone composition X.
• the silicone composition X that can be crosslinked into elastomer comprises:
• At least one heat resistance additive D which is cerium neodecanoate (IV).
• said silicone composition X having a cerium (IV) content of between 50 and 3000 ppm by mass.
• Silicone elastomer also relates to a silicone elastomer obtained by crosslinking composition X, at ambient temperature, optionally in the presence of humidity, or by heating.
• the heating is preferably carried out at a temperature between 80°C and 250°C.
• the duration of the heating varies according to the temperature and, possibly, according to the pressure exerted. According to one embodiment, the heating is carried out as follows:
• the silicone composition X makes it possible to obtain an elastomer which is thermally stable after heat treatment for 3 days at 300° C., 7 days at 275° C. or 21 days at 250° C.
• the elastomer obtained therefore has a very good thermal stability, which makes it possible to use it for the production of envelopes or primary insulators of single conductors used in the constitution of electrical wires or cables.
• the invention therefore also relates to an electric wire or electric cable comprising at least one conductive element 1 surrounded by at least one primary insulating layer 2 characterized in that said primary insulating layer 2 comprises a silicone elastomer obtained by crosslinking the composition silicone X.
• the invention also relates to the use of a silicone composition X for producing automobile cables, in particular automobile cables for electric or hybrid vehicles.
• the invention also relates to the use of a silicone composition X for the production of envelopes or primary insulators of single conductors used in the constitution of electrical wires or cables.
• the invention also relates to a method for manufacturing an electric wire or electric cable comprising the following steps: i. forming around an electrical conductor 1 at least one primary insulating layer 2 which consists of a material obtained by crosslinking the silicone composition X, preferably by heating to a temperature between 80° C. and 250° C., ii. optionally, assembling at least two insulated electrical conductors as obtained in step i, and iii. optionally, extruding an outer sheath as defined above around the insulated electrical conductor(s) of step i or ii.
• the formation around the electrical conductor 1 of at least one primary insulating layer 2 can be carried out by depositing the silicone composition X around the electrical conductor 1 according to the usual methods, in particular by extrusion processes.
• the deposit thus obtained is then crosslinked, preferably by heating, to lead to the formation of the primary insulator in silicone elastomer.
• the duration of the heating obviously varies with the temperature of the material and the possible working pressure. It is generally of the order of a few seconds to several minutes between 100 and 120°C and a few seconds between 180 and 200°C. It is possible to deposit several layers together using a tandem extrusion equipped for example with a crosshead or a co-extrusion.
• the electrical wire or cable according to the invention may further comprise an outer sheath surrounding the insulated electrical conductor or conductors.
• This outer sheath is well known to those skilled in the art. It can burn completely locally and turn into residual ash under the effect of the high temperatures of a fire without being a fire propagator.
• the material that makes up the outer sheath can be, for example, a polymer matrix based on polyolefin and at least one hydrated flame-retardant mineral filler chosen in particular from metal hydroxides such as, for example, magnesium dihydroxide or aluminum trihydroxide.
• the outer sheath is conventionally obtained by extrusion.
• the electric wire or electric cable according to the invention is characterized in that the primary insulating layer 2 is formed by depositing around the conductive element 1 of said silicone composition X by a technique of extrusion and by heating means so as to obtain a material temperature ranging from 80° C. to 250° C. until said silicone composition X has hardened.
• Cerium(IV) neodecanoate is synthesized according to the procedure described in EP0575189.
• Cerium(IV) neodecanoate is a liquid. It can be used pure (additive 1) or formulated (additives 2 and 3).
• Additive 1 The cerium content in Additive 1 is 16.6% by weight.
• Additive 2 cerium (IV) neodecanoate formulated in a mixer
• 56.6% by weight of a poly(dimethyl)(methylvinyl)siloxane gum, having 720 ppm of vinyl groups and a viscosity of 20 million mPa.s at 25° C. are mixed with 5.6% by weight of fumed silica treated with octamethylcyclotetrasiloxane, having a BET specific surface of 235 m 2 /g, then 37.8% by weight of neodecanoate of cerium (IV) is added.
• the mixture is mixed for 10 minutes at room temperature.
• Additive 3 cerium (IV) neodecanoate formulated on a cylinder
• 56.6% by weight of a poly(dimethyl)(methylvinyl)siloxane gum, having 720 ppm of vinyl groups and a viscosity of 20 million mPa.s at 25° C. are mixed with 5.6% by weight of fumed silica treated with octamethylcyclotetrasiloxane, having a BET specific surface of 235 m 2 /g, then 37.8% by weight of cerium (IV) neodecanoate is added.
• the mixture is mixed for 10 minutes at room temperature.
• Additives 2 and 3 have a cerium content by weight of 0.063% relative to the total weight of the additive. [0162] Addendum 4
• Additive 4 is an additive based on T1O2 and Fe 2 O3 in a silicone gum.
• the iron content is between 0.7 and 2.1% by weight.
• the T1O2 content is more than 94% by weight.
• Addendum 5 is cerium oxide purchased from Sigma Aldrich [0166] Additive 6
• Additive 6 is cerium (III) octoate purchased from Sigma Aldrich [0168] Additive 7
• Additive 7 is an antioxidant based on iron (III) ethyl-2-hexanoate in a silicone gum.
• the iron content is 0.78% by weight.
• composition HCR 1 [0170] Composition HCR 1:
• composition HCR 2 Base A [0172]
• a mixer is loaded with
• Part A of this LSR composition is mixed for 1 minute at 1000 revolutions per minute in the speed mixer.
• the Pt level is 10 ppm.
• Part B of this LSR composition is mixed for 1 minute at 1000 revolutions per minute in the speed mixer.
• Test plates (150mm ⁇ 150mm ⁇ 2mm) were produced in a 4-cavity mold under pressure for 8 minutes at 115°C. After a post-curing step of 4 h at 200° C. in a ventilated oven, the slabs underwent thermo-oxidative aging in ventilated ovens under different conditions of duration and temperature, detailed in the examples below.
• the mechanical properties in this case the Shore A hardness (IS0868, DIN53505), the breaking strength (IS037, DIN53504-51), the elongation at break (IS037, DIN53504-51), and the Tear resistance (ASTM D624 A) were measured on all the plates thus aged and compared with the mechanical properties measured on the initial plates post-annealed for 4 hours at 200°C.
• cerium (IV) neodecanoate (example 1) makes it possible to obtain good mechanical properties and better thermal resistance than cerium oxide (additive 5), cerium (III) octoate (additive 6) and iron (III) ethyl-2-hexanoate (additive 7), (Comp. Ex. 2-4). Furthermore, the mechanical properties obtained with cerium(IV) neodecanoate are comparable to those obtained for T1O2 (additive 4, ex. comp. 1). However, with cerium(IV) neodecanoate, the plate obtained is transparent, unlike the plate obtained with Ti0 2 (additive 4, ex. comp. 1).
• compositions according to the invention therefore make it possible to obtain a transparent silicone elastomer having good mechanical properties and good thermal resistance.
• the cerium(IV) neodecanoate was tested pure and formulated. The results are shown in Table 3.
• results show that it is possible to use pure or formulated cerium(IV) neodecanoate because the results obtained are comparable. These results also show that the elastomer obtained retains its good mechanical properties, and in particular elastomeric properties, even after thermal aging for 21 days at 250° C.
• Cerium(IV) neodecanoate was also tested in an LSR composition. The results are shown in Table 4.

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