EP3824480A1 - Electrical insulation material comprising a mixture of micrometric inorganic fillers and manufacturing process - Google Patents

Electrical insulation material comprising a mixture of micrometric inorganic fillers and manufacturing process

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Publication number
EP3824480A1
EP3824480A1 EP19762187.3A EP19762187A EP3824480A1 EP 3824480 A1 EP3824480 A1 EP 3824480A1 EP 19762187 A EP19762187 A EP 19762187A EP 3824480 A1 EP3824480 A1 EP 3824480A1
Authority
EP
European Patent Office
Prior art keywords
electrical insulation
micrometric
charge
composite material
composite
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19762187.3A
Other languages
German (de)
French (fr)
Inventor
Loriane DESMARS
Damien BACHELLERIE
Sébastien Pruvost
Jocelyne Galy
Servane HALLER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Centre National de la Recherche Scientifique CNRS
Universite Claude Bernard Lyon 1 UCBL
Institut National des Sciences Appliquees de Lyon
Universite Jean Monnet Saint Etienne
SuperGrid Institute SAS
Original Assignee
Centre National de la Recherche Scientifique CNRS
Institut National des Sciences Appliquees de Lyon
SuperGrid Institute SAS
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 Centre National de la Recherche Scientifique CNRS, Institut National des Sciences Appliquees de Lyon , SuperGrid Institute SAS filed Critical Centre National de la Recherche Scientifique CNRS
Publication of EP3824480A1 publication Critical patent/EP3824480A1/en
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
    • C08K3/013—Fillers, pigments or reinforcing additives
    • 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
    • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
    • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
    • C08G59/20—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the epoxy compounds used
    • C08G59/22—Di-epoxy compounds
    • C08G59/24—Di-epoxy compounds carbocyclic
    • C08G59/245—Di-epoxy compounds carbocyclic aromatic
    • 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
    • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
    • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
    • C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
    • C08G59/42—Polycarboxylic acids; Anhydrides, halides or low molecular weight esters thereof
    • 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
    • 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
    • C08K3/38—Boron-containing compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
    • 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
    • H01B3/40—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 epoxy resins
    • 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
    • C08K2003/2206—Oxides; Hydroxides of metals of calcium, strontium or barium
    • 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
    • C08K2003/2217—Oxides; Hydroxides of metals of magnesium
    • C08K2003/222—Magnesia, i.e. magnesium oxide
    • 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
    • C08K2003/2227—Oxides; Hydroxides of metals of aluminium
    • 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
    • C08K2003/2237—Oxides; Hydroxides of metals of titanium
    • C08K2003/2241—Titanium dioxide
    • 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
    • C08K3/24—Acids; Salts thereof
    • C08K3/26—Carbonates; Bicarbonates
    • C08K2003/265—Calcium, strontium or barium carbonate
    • 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
    • C08K3/38—Boron-containing compounds
    • C08K2003/382—Boron-containing compounds and nitrogen
    • C08K2003/385—Binary compounds of nitrogen with boron
    • 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
    • C08K2201/00—Specific properties of additives
    • C08K2201/014—Additives containing two or more different additives of the same subgroup in C08K
    • 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
    • C08K2201/00—Specific properties of additives
    • C08K2201/016—Additives defined by their aspect ratio
    • 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

Definitions

  • the present invention relates to a composite material for electrical insulation, which can in particular be used as a support for electrical conductors in high-voltage electrical equipment, such as substations in a metal envelope, commonly designated by the acronym PSEM, subjected to a high voltage i alternating and / or direct current.
  • PSEM high-voltage electrical equipment
  • an electrical substation in a metallic envelope consists of a high voltage electrical conductor held in the center of a metallic envelope using electrical insulating supports, such as spacers or "spacers" in English.
  • the outer casing is earthed and the electrical insulation of each phase from ground is provided by an insulating medium with high dielectric strength, typically SFe.
  • These stations are very “impact” and can be installed inside or outside buildings.
  • the material of the insulating supports In order to be used as an electrical insulator, the material of the insulating supports must have low porosity, high dielectric strength, low dielectric permittivity and low coefficient of thermal expansion. In addition, during their use, the electrical insulating supports are subjected to a permanent electrical stress which can cause the appearance of hot spikes locally. It is therefore important that the material of the insulating supports also has a high thermal conductivity, and this at the very least. long life of supports.
  • the electrical insulating supports are made of a composite material, the by an assembly of at least two components; immiscible.
  • the Insulating supports are composed of an organic matrix in which one or more charges are dispersed.
  • the matrix is an electrical insulating material, for example formed by the crosslinking of a reticulable mixture, possibly in the presence of a hardener.
  • the fillers can be of organic or inorganic type, micrometric or nanometric, and of all fbrmej. Other additives can be included in this matrix, such as diluents or plasticizers for example.
  • the electrical insulating supports can be prepared in different ways, for example by extrusion, molding or injection.
  • the injection process is of particular interest because it makes it possible, on the one hand, to reduce the defects which may appear during the design, such as vacuoles or deformations during removal of the material, and allows, on the other hand apart, a standardization of the parts obtained. Nevertheless, the injection step requires that the loaded crosslinkable mixture have a rheology adapted to allow gelation under automated pressure without the appearance of bubbles. Such rheology is also suitable for gravitational vacuum casting.
  • Matrix-charge interfaces are an area of high electrical stress. As shown in Figure 1, when tensioning a composite electrical insulation material A, hot spots (represented by stars) can appear at the matrix a - charge b interfaces, in particular when the matrix has low thermal conductivity. This is due to the absence of a phononic network which does not allow or very badly the transfer of thermal energy through the matrix.
  • nanometric charges Alone or in combination with micrometric fillers, they can allow a gain in dielectric strength and thermal conductivity.
  • nanometric fillers has drawbacks: need to control the dispersion of the charges to avoid the formation of aggregates, increase in viscosity, heavy hygiene and safety constraints during their use due to the need for '' avoid their dissemination in the air, high cost ...
  • Another solution for obtaining a high thermal conductivity consists in modifying the shape of the charges, and in particular in using charges having a high form factor, for example lamellar charges or charges in the form of needle. Indeed, the presence of charges with a high form factor allows a transfer of thermal energy along these charges, and over the entire network of charges, which makes it possible to increase the thermal conductivity of the material compared to a material with low form factor fillers.
  • the increase in the form factor can also allow the improvement of the dielectric strength thanks to their barrier effect.
  • the disadvantage of the lamellar fillers is that they cause a sharp increase in the viscosity of the crosslinkable mixture compared to the non-lamellar fillers. Consequently, the charge rates compatible with the implementation of the retlippable mixture are relatively low, which risks leading to materials whose coefficient of thermal expansion is too high, which resist resistance to surface erosion by discharges. partial and on the surface.
  • the present invention therefore aims to remedy this problem by proposing a composite electrical insulation material comprising an epoxy matrix of cycloallphatic type or of diglycidyl ether type, and from 15 to 45% by volume of charges relative to the total volume of composite material d electrical insulation.
  • the composite electrically insulating material according to the invention comprises a first micrometric inorganic charge having a form factor of less than 3 and a second lamellar inorganic mlcrometric charge having a form factor ranging from 3 to 100, the volume ratio between the first charge. and the second charge going from 95/05 to 40/60.
  • an “epoxy matrix” designates a crosslinked epoxy polymer.
  • the form factor of a particle is the ratio between the largest dimension of the particle considered and its smallest dimension.
  • the largest dimension of the particle is understood as the largest dimension of the particle when it is placed between two parallel planes.
  • the smallest dimension is the smallest dimension of the particle when it is between two parallel planes. The smallest dimension corresponds to the thickness of the particle when it is flat.
  • micrometric load is meant loads whose largest dimension is between 2 micrometers and 100 micrometers.
  • the dimensions are number average dimensions. These can be measured by the use of measurement software coupled to a microscope, such as a scanning electron microscope, SEM.
  • Lamellar filler is meant a filler having a shape factor greater than or equal to 3, and often greater than 5 or even greater than 10.
  • Lamellar fillers are generally in the form of stacked plates, plates, sheets or sheets. These fillers have a thickness generally between 5 and 500 nm, and a width and a length between 2 and 100 ⁇ m. These lamellar charges differ from charges in the form of a needle because of their shape. the lamellar charges are flat with a thickness at least 4 times and at most 20,000 fibers less than their width and their length, while the charges in the form of a needle are longliform and have a thickness and a width very much less than their length by at least 4 times and at most 20,000 fols.
  • the composite electrical insulation material according to the invention has the advantage of being able to be prepared by an injection process or by gravitational casting while having a high dielectric strength, a low coefficient of thermal expansion, a low porosity, a thermal conductivity. relatively high, and advantageously also low dielectric permittivity. Indeed, the judicious choice of the shape and size of the fillers, and of their respective contents, made it possible to find a balance between these properties which are a priori contradictory.
  • the composite electrical insulation material according to the invention may also have one or more of the following additional characteristics:
  • the second micrometric inorganic filler has a form factor ranging from 10 to 50
  • the second micrometric inorganic charge is chosen from BN and AI2O3, and preferably from hBN and AI2O3;
  • the first micrometric inorganic charge is chosen from
  • the content of fillers ranges from 20 to 40% by volume, and preferably from 25 to 35% by volume, relative to the total volume of the composite electrical insulation material;
  • the volume ratio between the first micrometric inorganic charge and the second micrometric inorganic charge ranges from 70/30 to 50/50;
  • the matrix is an epoxy matrix of the dlglycldylether type, and preferably an epoxy matrix of the diglycidylether type of bisphenol A (DGEBA);
  • the electrical dlsolatlon composite material further comprises a third micrometric charge, distinct from the first micrometric inorganic charge and from the second micrometric inorganic charge;
  • the first micrometric inorganic filler and / or the second micrometric inorganic filler and / or, when it is present, the third micrometric filler are functionalized at the surface;
  • the electrical insulation composite material is in the form of an electrically insulating support capable of holding an electrical conductor in position in a station in a metallic envelope.
  • the "crosslinkable mixture” is understood to mean the mixture of an epoxy resin of the cycloaliphatic type or of the glycicyl ether type, of the first and second micrometric inorganic charges, as defined in the context of the invention , a crosslinking agent, and possibly one or more additional charges el / or additive (3).
  • a crosslinking agent such as a crosslinking agent, as explained below.
  • epoxy resin designates an epoxy monomer or prepolymer.
  • crosslinker an agent (that is to say a chemical compound) for crosslinking the epoxy resin.
  • the crosslinking agent can be an activator or initiator, or a hardener in combination with an activator or with an initiator, or a combination of an activator, an initiator and a hardener.
  • the method according to the invention is easy to implement, and leads to a composite material of electrical insulation having a low porosity, a high dielectric strength, a low dielectric permltivity, a low coefficient of thermal expansion, and a high thermal conductivity.
  • the method according to the invention may also have one or more of the following additional characteristics:
  • the crosslinkable mixture has a viscosity ranging from 6000 mPa.s to 15000 mPa.s, preferably from 10000 mPa.s to 12000 mPas, measured at 80 ° C according to ISO standard 12058;
  • the crosslinking agent is an activator, or an initiator, or a hardener in combination with an activator or with an initiator, or else a combination of an activator, an initiator and a hardener;
  • the introduction of the crosslinkable mixture into the mold is done by gravitational casting or by injection into the mold;
  • crosslinking is carried out by application of a crosslinking means such as heating or UV;
  • the crosslinkable mixture further comprises a third micrometric charge.
  • crosslinking means is a physical means allowing the crosslinking of the crosslinkable mixture, such as heating or UV.
  • Another object of the invention relates to a station in a metal envelope (PSEM) comprising an external envelope internally delimiting an enclosure in which is mounted a high voltage electrical conductor using electrical insulating supports made of a composite material of electrical insulation. according to llnvention, or made of an electrical material obtained by the method according to llnvention.
  • PSEM metal envelope
  • Figure 1 is a schematic view of a composite electrical insulation material outside the invention, composed of a matrix and of charges having a form factor of less than 3.
  • the stars represent hot points appearing at the charge-matrix interface .
  • Figure 2 is a schematic view of a composite insulation material according to the invention.
  • the stars represent hot spots appearing at the charge-matrix interface.
  • the arrows represent the heat transfer.
  • Figure 3 is a sectional view of an electrical substation in a metal casing comprising an electrically insulating support in the form of a cone.
  • Figure 4 is a sectional view of an electrical substation in a metal casing comprising an electrically insulating support in the form of a "post-type".
  • the invention relates to a composite electrical insulation material 1 adapted to be used to form electrically insulating supports to hold in position the conductors present in the SEMCs.
  • the electrical insulation composite material is composed of a matrix 2 in which a mixture of micrometric inorganic charges is dispersed.
  • the matrix 2 is formed by the crosslinking of an epoxy resin of the cycloallphatic type or of an epoxy resin of the diglycidyl ether type.
  • the matrix 2 is a matrix of diglycidyl ether type, and in particular diglycidyl ether of blsphenol A.
  • the electrical insulation composite material 1 also comprises a mixture of at least two distinct micrometric inorganic fillers. The presence of these two charges makes it possible to increase the thermal conductivity of the composite electrical insulation material 1 as well as its electrical resistance.
  • the first micrometric inorganic filler 3 has a form factor of less than 3, and preferably less than or equal to 2, or even less than or equal to 1.5.
  • the first micrometric inorganic charge 3 with a form factor of less than 3 can be of any shape, and in particular spherical or almost spherical.
  • any micrometric inorganic filler with a factor of less than 5, having electrical insulation and thermal conductivity, may be suitable as the first charge 3 in the context of the invention.
  • the first micrometric inorganic filler 3 mention may be made of silica (SlOz), alumina (AI 2 O 3 ), aluminum hydroxide (AI (OH) 3 ), calcium oxide (CaO ), magnesium oxide (MgO), calaum carbonate (CaC0 3 ), and titanium dioxide CTIO 2 ).
  • the first micrometric inorganic filler 3 is chosen from silica (S1O 2 ) or alumina (AI 2 O 3 ).
  • the composite electrical insulation material 1 preferably comprises a single charge of the first micrumetric inorganic charge type 3. Nevertheless, the composite electrical insulation material 1 can comprise several charges of the first micrometric inorganic charge type 3, and in particular two.
  • the second micrometric inorganic filler 4 is of the lamellar type and has a form factor ranging from 3 to 100, and preferably from 10 to 50.
  • the second micrometric inorganic filler 4 is therefore neither of the spherical type nor in the form of a needle.
  • any inorganic micrometric lamellar filler with a form factor ranging from 3 to 100 may be suitable in the context of the invention as a second filler 4.
  • boron nitride may be mentioned (BN) in particular in hexagonal form (hBN), or alumina (AI 2 O 3 ).
  • the second micrometric inorganic filler 4 and chosen from boron nitride in hexagonal form (hBN) or and alumina (AI 2 O 3 ).
  • the second micrometric inorganic charge 4 lamellar is not in the form of an aggregate. Otherwise, the aggregates are preferably broken during the preparation of the electrical insulation material 1, as detailed below.
  • the composite electrical insulation material 1 preferably comprises a single charge of the second inorganic micrometric lamellar charge type 4. Nevertheless, the composite electrical insulation material 1 can comprise several charges of the second micrometric inorganic charge type 4, and in particular two.
  • the composite material of electrical insulation comprises from 15 to 45% by volume of charges relative to the total volume of the composite electrical insulation material 1, and preferably from 20 to 40% by volume, and better still from 25 to 35% by volume.
  • This content is understood as the total content of fillers, that is to say the content of first micrometric inorganic filler 3, of second micrometric inorganic lamellar filler 4 and of additional fillers when these are present, as set out below. after.
  • the first and second micrometric inorganic fillers are present in the electrical insulation composite material 1 in a volume ratio ranging from 95/05 to 40/60, and preferably ranging from 70/30 to 50/50.
  • the first micrometric inorganic filler 3 is chosen from alumina (AI2O5) and silica (Si ⁇ 1 ⁇ 4)
  • the second micrometric lamellar inorganic filler 4 is chosen from boron nltride in hexagonal form (hBN) and alumina (AI2O3).
  • the epoxy resin is an epoxy resin of the diglyddylether type, and for example a resin of the diglyddylether type of bisphenol A, the first micrometric inorganic filler 3 is chosen from alumina (AI2O3) and silica (Si0 2 ), and the second inorganic micrometric lamellar filler 4 is chosen from boron nltride in hexagonal form (hBN) and alumina (AI2O3).
  • AI2O3 alumina
  • Si0 2 silica
  • the second inorganic micrometric lamellar filler 4 is chosen from boron nltride in hexagonal form (hBN) and alumina (AI2O3).
  • the presence of the second inorganic micrometric lamellar charge 4 makes it possible to increase the thermal conductive paths in the material, ideally by contact between the particles but also by reducing the distance between the charges within the matrix to a virtual contact, ⁇ which considerably reduces the damage to the material due to the appearance of hot spots.
  • the first inorganic charge micrometric 3 having a form factor Less than 3 makes it possible to fill the empty spaces between the second inorganic micrometric lamellar fillers 4, and thus further improve the thermal conductivity of the material.
  • the second inorganic micrometric lamellar charge 4 also makes it possible to improve the dielectric rigidity of the material, and in particular in comparison with the micrometrical inorganic charges in the form of needle by making a physical barrier to the propagation of electron in the material greater due to their shape.
  • the composite electrical insulation material 1 also comprises one or more other charges, different from the first and from the second micrometric inorganic charges J and 4, called additional charges.
  • these additional charges are micrometric and can be organic or inorganic charges, of any shape.
  • additional fillers mention may be made of glass fibers.
  • the additional charges do not represent more than 10% by volume, and preferably not more than 5%, relative to the total volume of the composite electrical insulation material 1.
  • these charges additional allow to improve mechanical or physicochemical properties according to the applications, for example hydrophobicity, resistance to torsion, compression, flame.
  • one or more charges can be functionalized on the surface. This functionalallows in particular to improve the compatibility of the charges with the matrix, and then to improve the thermal conductivity of the material and the coefficient of thermal expansion.
  • the surface functionalizations of the charges are usual in the state of the art and will not be detailed here.
  • the composite electrical insulation material 1 can also include additives such as plasticizers.
  • the composite electrical insulation material 1 according to the invention is weakly porous, and preferably does not contain porosities. Indeed, high porosity would prevent use as an electrical insulator for high voltage.
  • the composite electrical insulation material 1 according to the invention is prepared by introducing a crosslinkable mixture into a mold, followed by a crosslinking step.
  • the first step is to prepare a crosslinkable mixture.
  • a crosslinkable mixture for this, an epoxy resin of cycloaliphatic type or one of dlglycidylether type, and in particular an epoxy resin of dlglyddylether type of btsphenol A.
  • the first and second micrometric inorganic fillers 3 and 4 as defined above, and a crosslinking agent are mixed according to any technique known to those skilled in the art. When the mixture comprises additional fillers and / or additives, these are incorporated into the crosslinkable mixture during this first step.
  • an epoxy resin - fillers premix and a crosslinking agent - fillers premix can be prepared and then brought into contact in order to prepare the crosslinkable mixture.
  • the second micrometric inorganic 4 lamellar filler used is not in the form of an aggregate.
  • the second inorganic micrometric 4-lamellar charge used is in the form of an aggregate.
  • the method then advantageously comprises a step during which the aggregates are broken, either upstream. of the preparation of the durdssable mixture, that is during its preparation. Methods for breaking the aggregates of lamellar charges are well known in the state of the art and will not be detailed here.
  • the crosslinkable mixture comprises a crosslinking agent.
  • the crosslinking agent may be an activator or initiator or a curing agent in combination with an activator or an initiator, or a comb i bination of an activator, an initiator and a hardener.
  • the activators, hardeners and initiators which can be used for the crosslinking of the epoxy resin of cycloaliphatic type or of diglydcylether type are those usually employed in the state of the art.
  • hardeners mention may be made of dlamines and anhydrides.
  • the crosslinkable mixture must have a viscosity allowing manufacture by gravitational casting under vacuum or by gelling under automated pressure.
  • the crosslinkable mixture obtained has a viscosity belonging to the range going from 6000 mPa.s to 15000 mPa.s, preferably going from 10000 mPa.s to 12000 mPa.s measured at 80 ° C according to the ISO 12058 standard.
  • the crosslinkable mixture obtained has a viscosity belonging to the range from 15,000 mPa.s to 29,000 mPa.s, preferably from 18,000 mPa.s to 24,000 mPa.s, measured at 50 ° C according to ISO 12058 standard.
  • the control of the viscosity of the crosslinkable mixture is important, because too high a viscosity would lead to a crosslinkable mixture comprising bubbles, and therefore a final material comprising defects and / or porous.
  • a high viscosity would make the crosslinkable mixture difficult to introduce into the mold by injection or by gravitational casting.
  • a too low viscosity would reduce the efficiency of the manufacturing process by gelation under automated pressure.
  • the increase in viscosity due to these high levels of fillers is limited, which allows the gravitational casting of the crosslinkable mixture or its injection into a mold.
  • crosslinkable mixtures had a rheology adapted to be implemented by gravitational casting, or even to be able to be injected into a mold, by judiciously choosing the nature and the shape of these fillers and their proportions, and lead to a material. not very porous. This is all the more surprising since the presence of lamellar fillers at these high rates is known to usually increase the viscosity of the mixture so that this implementation is difficult, if not impossible.
  • the distribution of the charges in the crosslinkable mixture is homogeneous.
  • the second step of the manufacturing process according to the invention consists in introducing the crosslinkable mixture, obtained in the first step, into a mold having the desired shape.
  • This introduction can be carried out according to any technique known to those skilled in the art.
  • this introduction into the mold is carried out either by gravitational casting or by injection according to any technique known in the state of the art.
  • the third stage consists in cross-linking the crosslinkable mixture previously introduced into the mold.
  • This step can be carried out according to any technique known to those skilled in the art. According to a particular embodiment, this crosslinking step can be carried out in the presence of a crosslinking means, such as heating or UV for example.
  • the setting time is advantageously greater than or equal to one hour.
  • the last step of the method consists in demolding the structure obtained and made of composite material of electrical insulation 1, according to any technique known in the state of the art.
  • the structure made of composite material of electrical insulation 1 thus obtained is easy to prepare by injection or gravitational casting, has good thermal conductivity and electrical insulation properties, a low coefficient of thermal expansion, and a high dielectric strength.
  • the structure made of composite electrical insulation material 1 thus obtained also has a low dielectric permittivity.
  • the composite electrical insulation material obtained by the method according to the invention has a low porosity, and preferably is not porous. According to a particular embodiment, it is possible to further reduce the porosity of the tomposite material of electrical insulation 1, or even to eliminate it completely, by carrying out one or more degassings of the crosslinkable mixture, before its introduction into the mold. For example, degassing can be carried out under reduced pressure of ten millibars, preferably by mixing said crosslinkable mixture.
  • the invention also relates to a station in a metal casing 5 comprising an external casing 6 internally delimiting an enclosure 7 dan ⁇ which is mounted a high voltage electrical conductor 8 held in position by electrically insulating supports 9 made of a composite electrical insulation material 1 according to the invention.
  • the outer metal casing G has a cylindrical shape. This example is not limitative.
  • a high-voltage electrical conductor 8 of any known type on the ground is mounted inside the external metal casing G.
  • the high-voltage electrical conductor 8 is tubular in the embodiment shown in FIGS. 3 and 4.
  • the high voltage electrical conductor 8 is held in the center of the external metal casing 6 using electrically insulating supports 9, such as spacers produced in the examples illustrated by cones ( Figure 3) or "post-types * ( Figure 4).
  • electrically insulating supports 9 are made of a composite material of electrical insulation 1 according to the invention.
  • the internal volume of the enclosure 7 is filled with an insulating fluid, typically an insulating gas such as SFe.
  • an insulating fluid typically an insulating gas such as SFe.
  • a composite material of electrical insulation A according to the intention and four materials of electrical insulation except Invention (B (without load) - C (with only a load having a form factor lower than 3), D (with only a lamellar load) and E (with a volume ratio between the form factor charge less than 3 and the lamellar charge outside the invention) were prepared (see Table 1).
  • the total charge content a of the composite material D could not be increased until 37% by volume due to the too high viscosity of the crosslinkable mixture.
  • the epoxy resin used is the epoxy resin of the diglycldylether type of bisphenol A (DGfcBA) supplied by Huntsman under the reference CY 5925.
  • the fillers used in the various composite materials are a micrometric alumina supplied by the Imerys under the reference Alodur®WSK, and the hexagonal boron nltride hBN supplied by Momentlve under the reference PT120.
  • a hardener as crosslinking agent was also used: an anhydride sold under the reference HY5925 by the company Huntsman.
  • Materials A to E are prepared as follows. The charges are dried at 80 ° C under primary vacuum for 24 hours before use. An epoxy resin - fillers and hardener - fillers premix is made in order to facilitate the dispersion of the fillers. The premixes are then mixed in proportions such that the mass ratio of epoxy resin: hardener is 100; 80. All the mixes are carried out using a SpeedMixer DAC 400 planetary mixer at 2500 rpm. The crosslinkable mixture is then degassed under primary vacuum at S0 ° C for 1 hour, then is then poured by gravltional casting into a closed aluminum mold, the surface of which has been treated with a release agent. The mixture is finally crosslinked by heating according to the temperature cycle following r 4 h at 100 ° C then 8 h at 140 ° C.
  • the properties of the different materials A to D were evaluated: viscosity (measured at 50 ° C according to ISO 12058 standard), dielectric strength (measured according to ISO 60243-1), thermal conductivity (measured according to ISO 8894 standard) and the coefficient of thermal expansion.
  • the coefficient of thermal expansion (CTE) was determined using a TMA (Thermomechanlcal Analyzer) Q400 TA Instruments from 40 ° C to 170 ° C.
  • the force applied by the quadrant expansion probe is 5 mN and the temperature ramp is 3 u C / min.
  • the measurement is made under nitrogen.
  • the curves used are those obtained in the 2nd temperature rise.
  • the results obtained are summarized in Table 2.
  • the material E was used to illustrate the importance of the ratios between charges and only the values of electrical rigidity and thermal conductivity were evaluated.
  • the viscosity of crosslinkable mixtures is affected by the presence and nature of the fillers.
  • the crosslinkable mixture B without filler has the lowest viscosity. This viscosity is higher in Mixed C due to the presence of polydisperse alumina.
  • the viscosity when the crosslinkable mixture contains only hBN as a filler is very high, so that the total content in mixture D is 17%.
  • the crosslinkable mixture A according to the invention has a high total content of fillers, and an alumina load ratio hBN of 86.5 / 13.5, while having a viscosity allowing its implementation.
  • the composite material A according to the invention has a dielectric strength similar to that of the composite material C outside the invention, and substantially lower than that of the material B outside the invention.
  • the addition of lamellar charge in the composite material A according to the invention does not negatively affect the dielectric strength.
  • the composite material E also has a dielectric strength equivalent to the composite material C and the low charge of the lamellar type seems to have no impact on this property.
  • the thermal conductivity is higher in the composite material A according to the invention compared to all the composite materials outside the invention tested (thermal conductivity increased by at least 25%).
  • the thermal conductivity of the material E is very slightly higher than that of the material C and falls within the margin of error of the latter.
  • the small addition of lamellar charge in the material E therefore appears to be insufficient for the latter to be in sufficient quantity allowing it to have a positive impact on this property.
  • the coefficient of thermal expansion is lower for the composite material A according to the invention, compared to materials B, C and D outside the invention (reduction up to 50%).
  • the composite material A according to the invention makes it possible to combine satisfactory dielectric rigidity, high thermal conductivity, and a low coefficient of thermal expansion while being easy to use thanks to a controlled viscosity. of the crosslinkable mixture.
  • the composite material A has a very low porosity.

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Abstract

The invention relates to a composite electrical insulation material (1) comprising an epoxy matrix (2) of cycloaliphatic type or of diglycidyl ether type, and from 15 to 45% of fillers, including a first micrometric inorganic filler (3) having an aspect ratio of less than 3 and a lamellar second micrometric inorganic filler (4) in a volume ratio ranging from 95/05 to 40/60. The invention also relates to the process for manufacturing such a composite electrical insulation material (1), and also to the use thereof for electrically insulating supports (9) in a metal-enclosed substation (5).

Description

MATERIAU D'ISOLATION ELECTRIQUE COMPRENANT UN MELANGE DE CHARGES INORGANIQUES MICROMETRIQUES ET PROCEDE DE ELECTRICAL INSULATION MATERIAL COMPRISING A MIXTURE OF MICROMETRIC INORGANIC CHARGES AND METHOD OF MAKING SAME
F ABRICATION F ABRICATION
La présente invention concerne un matériau composite d'isolation électrique, pouvant notamment être utilisé comme support pour conducteurs électriques dans des appareillages électriques a haute tension, comme les postes sous enveloppe métallique, désignés couramment par l'acronyme PSEM, soumis à une haute tension i courant alternatif et/ou continu. The present invention relates to a composite material for electrical insulation, which can in particular be used as a support for electrical conductors in high-voltage electrical equipment, such as substations in a metal envelope, commonly designated by the acronym PSEM, subjected to a high voltage i alternating and / or direct current.
Classiquement, un poste électrique sous enveloppe métallique est constitué d'un conducteur électrique haute tension maintenu au centre d'une enveloppe métallique à l'aide de supports isolante électriques, tels que des entretoises ou * spacers » en anglais. L'enveloppe externe est mise à la terre et l'isolation électrique de chaque phase por rapport à la masse est assurée par un milieu isolant à forte rigidité diélectrique, typiquement SFe. Ces postes sont très «impacts et peuvent être installés à l'intérieur ou à l'extérieur des bâtiments.  Conventionally, an electrical substation in a metallic envelope consists of a high voltage electrical conductor held in the center of a metallic envelope using electrical insulating supports, such as spacers or "spacers" in English. The outer casing is earthed and the electrical insulation of each phase from ground is provided by an insulating medium with high dielectric strength, typically SFe. These stations are very “impact” and can be installed inside or outside buildings.
Afin d'être utilisé en tant quisolant électrique, le matériau des supports isolants doit avoir une faible porosité, une haute rigidité diélectrique, une faible permittivité diélectrique et un faible coefficient d'expansion thermique. De plus, lors de leur utilisation, le^ supports Isolante électriques sont soumis à une contrainte électrique permanente pouvant provoquer l'apparition de pointe chauds localement II est donc Important que le matériau des supports Isolante ait également une conductivité thermique élevée, et ce tout au long de la durée de vie des supporte.  In order to be used as an electrical insulator, the material of the insulating supports must have low porosity, high dielectric strength, low dielectric permittivity and low coefficient of thermal expansion. In addition, during their use, the electrical insulating supports are subjected to a permanent electrical stress which can cause the appearance of hot spikes locally. It is therefore important that the material of the insulating supports also has a high thermal conductivity, and this at the very least. long life of supports.
Généralement, les supports isolants électriques sont réalisés en un matériau composite, l.e. en un assemblage d'au moins deux composant; non miscibles. Typiquement, les supports Isolants sont composés d'une matrice organique dans laquelle sont dispersées une ou plusieurs charges, La matrice est un matériau isolant électrique, par exemple formé par la réticulation d'un mélange rétlculable, éventuellement en présence d'un durcisseur. Les charges peuvent être de type organique ou inorganique, micrométrique uu nanomëtrique, et de toutes fbrmej. D'autres additifs peuvent être Inclus dans cette matrice, comme des diluants ou des plastifiants par exemple. Generally, the electrical insulating supports are made of a composite material, the by an assembly of at least two components; immiscible. Typically, the Insulating supports are composed of an organic matrix in which one or more charges are dispersed. The matrix is an electrical insulating material, for example formed by the crosslinking of a reticulable mixture, possibly in the presence of a hardener. The fillers can be of organic or inorganic type, micrometric or nanometric, and of all fbrmej. Other additives can be included in this matrix, such as diluents or plasticizers for example.
Les supports isolants électriques peuvent être préparés de différentes manières, par exemple par extrusion, moulage ou injection. Le procédé par injection revêt un intérêt particulier car celui-ci permet, d'une part, de réduire les défauts pouvant apparaître lors de la conception, tels que des vacuoles ou des déformations lors ju retrait de la matière, et permet, d'autre part, une uniformisation des pièces obtenues. Néanmoins, l'étape d'injection Impose que le mélange réticulable chargé ait une rhéologie adaptée pour permettre une gélification sous pression automatisée sans apparition de bulles. Une telle rhéologie est aussi adaptée a une coulée gravitationnelle sous vide.  The electrical insulating supports can be prepared in different ways, for example by extrusion, molding or injection. The injection process is of particular interest because it makes it possible, on the one hand, to reduce the defects which may appear during the design, such as vacuoles or deformations during removal of the material, and allows, on the other hand apart, a standardization of the parts obtained. Nevertheless, the injection step requires that the loaded crosslinkable mixture have a rheology adapted to allow gelation under automated pressure without the appearance of bubbles. Such rheology is also suitable for gravitational vacuum casting.
Les Interfaces matrice-charge sont une zone de forte contrainte électrique. Tel que cela est représenté à la Figure 1, lors de la mise souc tension d'un matériau composite d'isolation électrique A, des points chauds (représentes par des étoiles) peuvent apparaître aux interfaces matrice a - charge b, en particulier lorsque la matrice possède une faible conductivité thermique. Ceci est dû à l'absence de réseau phononique qui ne permet pas ou très mal le transfert d'énergie thermique à travers la matrice.  Matrix-charge interfaces are an area of high electrical stress. As shown in Figure 1, when tensioning a composite electrical insulation material A, hot spots (represented by stars) can appear at the matrix a - charge b interfaces, in particular when the matrix has low thermal conductivity. This is due to the absence of a phononic network which does not allow or very badly the transfer of thermal energy through the matrix.
Des recherches ont été menées pour améliorer simultanément la conductivité thermique et la rigidité diélectrique des matériaux composites d'isolation électrique, et ont porté soit sur la matrice elle-même, soit sur les charges.  Research has been carried out to simultaneously improve the thermal conductivity and the dielectric strength of composite materials for electrical insulation, and has focused either on the matrix itself or on the charges.
En ce qui concerne la matrice, les recherches ont porté sur la nature chimique de la matrice ou sur la modification de l'agent de réticulation par exemple. Cependant, toute modification de la matrice Impose d'adapter le procédé de fabrication du matériau composite d'isolation électrique.  With regard to the matrix, research has focused on the chemical nature of the matrix or on the modification of the crosslinking agent for example. However, any modification of the matrix requires adapting the manufacturing process of the composite electrical insulation material.
En ce qui concerne le charges, plusieurs solutions ont également été envisagées. En particulier, l'augmentation significative du taux de charge est une solution répandue pour atteindre une conductivité thermique élevée. Néamoins, cette solution présente généralement l'inconvénient de conduire à des matériaux à faible rigidité diélectrique. De plus, un fort taux de charges conduit à ur mélange rétlculable de viscosité élevée, ce qui peut rendre difficile l'étape de mise en œuvre et générer des défauts dans le matériau obtenu (par exemple une augmentation de la porosité). With regard to the charges, several solutions have also been envisaged. In particular, the significant increase in the charge rate is a popular solution for achieving high thermal conductivity. However, this solution generally has the disadvantage of leading to materials with low dielectric strength. In addition, a high level of fillers leads to a reticulable mixture of high viscosity, which can make the implementation step difficult and generate defects in the material obtained (for example an increase in porosity).
Une autre solution répandue consiste à utiliser des charges nanométriques. Seules ou en combinaison avec des charges micrométriques, elles peuvent permettent un gain en rigidité diélectrique et en conductivité thermique. Cependant, l'ajout de charges nanométriques présente des inconvénients : nécessité de contrôler de la dispersion des charges pour éviter la formation d'aggrégats, augmentation de la viscosité, contraintes lourdes d'hygiène et sécurité lors de leur utilisation en raison de la nécessité d'éviter leur dissémination dans l'air, coût élevé...  Another widespread solution consists in using nanometric charges. Alone or in combination with micrometric fillers, they can allow a gain in dielectric strength and thermal conductivity. However, the addition of nanometric fillers has drawbacks: need to control the dispersion of the charges to avoid the formation of aggregates, increase in viscosity, heavy hygiene and safety constraints during their use due to the need for '' avoid their dissemination in the air, high cost ...
Une autre solution pour obtenir une conductivité thermique élevée consiste à modifier la forme des charges, et notamment à utiliser des charges ayant un facteur de forme élevé, par exemple des charges lamellaires ou des charges sous forme d'aiguille. En effet, la présence de charges à facteur de forme élevé permet un transfert d'énergie thermique le long de ce charges, et sur l'ensemble du réseau de charges, ce qui permet d'augmenter la conductivité thermique du matériau par rapport à un matériau comportant des charges à faible facteur de forme.  Another solution for obtaining a high thermal conductivity consists in modifying the shape of the charges, and in particular in using charges having a high form factor, for example lamellar charges or charges in the form of needle. Indeed, the presence of charges with a high form factor allows a transfer of thermal energy along these charges, and over the entire network of charges, which makes it possible to increase the thermal conductivity of the material compared to a material with low form factor fillers.
De plus, dans le cas de charges lamellaires, l'augmentation du facteur de forme peut également permettre l'amélioration de la rigidité diélectrique grâce à leur effet barrière. Néanmoins, l'Inconvénient des charges lamellaires est qu'elles entraînent une forte augmentait^ de la viscosité du mélange rétlculable par rapport aux charges non lamellaires. Par conséquent, les taux de charges compatibles avec la mise en œuvre du mélange rétlculable sont relativement faibles, ce qui risque de conduire à des matériaux dont le coefficient d'expansion thermique est trop élevé, qui résistent mal à l'érosition de surface par décharges partielles et au cheminement en surface. Dana le cas des charges sous forme d'aiguille, leur forme permet un transfert d'énergie thermique, ce qui permet d'envisager une application des compositions réticulables les comprenant dans l'isolation themique de composants électriques, comme décrit dans la demande EP 2 455 420 par exemple. Cependant, les charges sous forme d'aiguille ne permettent pao d'améliorer suffisamment la rigidité diélectrique juste de par leur forme pour envisager une utilisation comme matériau d'isolation électrique pour la très haute tension. De plus, là encore, l'emploi de ces charges entraîne une forte augmentation de la viscosité du mélange réticulable, ce qui rend sa fabrication plus difficile. In addition, in the case of lamellar fillers, the increase in the form factor can also allow the improvement of the dielectric strength thanks to their barrier effect. However, the disadvantage of the lamellar fillers is that they cause a sharp increase in the viscosity of the crosslinkable mixture compared to the non-lamellar fillers. Consequently, the charge rates compatible with the implementation of the retlippable mixture are relatively low, which risks leading to materials whose coefficient of thermal expansion is too high, which resist resistance to surface erosion by discharges. partial and on the surface. In the case of charges in the form of a needle, their shape allows a transfer of thermal energy, which makes it possible to envisage an application of the crosslinkable compositions comprising them in the thermal insulation of electrical components, as described in the application EP 2 455,420 for example. However, the charges in the form of a needle do not allow pao to sufficiently improve the dielectric rigidity just by their shape to envisage use as an electrical insulation material for very high voltage. In addition, here again, the use of these fillers results in a sharp increase in the viscosity of the crosslinkable mixture, which makes its manufacture more difficult.
Il existe donc un bejoin d'un matériau composite d Isolation électrique qui, non seulement, a une faible porosité, une haute rigidité diélectrique, une faible permittivité diélectrique et un faible coefficient d'expansion thermique, une conductivité thermique élevée, et ce tout au long de sa durée de vie, mais également qui soit facile de mise en œuvre par un procédé par Injection ou par coulée gravitationnelle.  There is therefore a need for a composite material of electrical insulation which, not only, has a low porosity, a high dielectric rigidity, a low dielectric permittivity and a low coefficient of thermal expansion, a high thermal conductivity, and this at the over its lifetime, but also which is easy to implement by an injection process or by gravitational casting.
La présente invention vise donc à remédier à ce problème en proposant un matériau composite d'isolation électrique comprenant une matrice époxy de type cycloallphatique ou de type diglycidyléther, et de 15 à 45% en volume de charges par rapport au volume total de matériau composite d'isolation électrique. Le matériau composite d'isolation électrique selon l'invention comprend une première charge inorganique micrométrique ayant un facteur de forme Inférieur à 3 et une deuxième charge inorganique mlcrométrique lamellaire ayant un facteur de forme allant de 3 à 100, le ratio volumique entre la première charge et la deuxième charge allant de 95/05 à 40/60.  The present invention therefore aims to remedy this problem by proposing a composite electrical insulation material comprising an epoxy matrix of cycloallphatic type or of diglycidyl ether type, and from 15 to 45% by volume of charges relative to the total volume of composite material d electrical insulation. The composite electrically insulating material according to the invention comprises a first micrometric inorganic charge having a form factor of less than 3 and a second lamellar inorganic mlcrometric charge having a form factor ranging from 3 to 100, the volume ratio between the first charge. and the second charge going from 95/05 to 40/60.
Dans le cadre de l'invention, une « matrice époxy » désigne un polymère époxy réticulé.  In the context of the invention, an “epoxy matrix” designates a crosslinked epoxy polymer.
Le facteur de forme d'une particule est le ratio entre la plus grande dimension de la particule considérée et sa plus petite dimension. Dans le cadre de l'invention, la plus grande dimension de la particule s'entend comme la plus grande dimension de la particule lorsque celle-ci est placée entre deux plans parallèles. De la même manière, la dimension la plus petite est la dimension la plus petite de la particule lorsque celle-ci est comprise entre deux plans parallèles. La plus petite dimension correspond à l'épaisseur de la particule lorsque celle-ci est plate. The form factor of a particle is the ratio between the largest dimension of the particle considered and its smallest dimension. In the context of the invention, the largest dimension of the particle is understood as the largest dimension of the particle when it is placed between two parallel planes. Likewise, the smallest dimension is the smallest dimension of the particle when it is between two parallel planes. The smallest dimension corresponds to the thickness of the particle when it is flat.
Par « charge micrométrique », on entend des charges dont la plus grande dimension est comprise entre 2 micromètres et 100 micromètres.  By "micrometric load" is meant loads whose largest dimension is between 2 micrometers and 100 micrometers.
Dans le cadre de l'invention, les dimensions sont des dimensions moyennes en nombre. Celles-ci peuvent être mesurées par l'empk l d'un logiciel de mesure couplé à un microscope, tel qu'un microscope électronique à balayage, MEB.  In the context of the invention, the dimensions are number average dimensions. These can be measured by the use of measurement software coupled to a microscope, such as a scanning electron microscope, SEM.
Par « charge lamellaire », on entend une charge ayant un facteur de forme superleur ou égal à 3, et souvent supérieur à 5 voire supérieur à 10. Les charges lamellaires se présentent généralement sous la forme de plaques, plaquettes, feuilles ou feuillets empilés. Ces charges ont une épaisseur généralement comprise entre 5 et 500 nm, et une largeur et une longueur comprises entre 2 et 100 pm. Ces charges lamellaires se distinguent des charges sous forme d'aiguille en raison de leur forme . les charges lamellaires sont plates avec une épaisseur au moins 4 fois et au plus 20000 fols inférieure à leur largeur et à leur longueur, tandis que les charges sous forme d'aiguille sont longlformes et ont une épaisseur et une largeur très largement inférieures à leur longueur par au moins 4 fois et au plus 20000 fols.  By "lamellar filler" is meant a filler having a shape factor greater than or equal to 3, and often greater than 5 or even greater than 10. Lamellar fillers are generally in the form of stacked plates, plates, sheets or sheets. These fillers have a thickness generally between 5 and 500 nm, and a width and a length between 2 and 100 μm. These lamellar charges differ from charges in the form of a needle because of their shape. the lamellar charges are flat with a thickness at least 4 times and at most 20,000 fibers less than their width and their length, while the charges in the form of a needle are longliform and have a thickness and a width very much less than their length by at least 4 times and at most 20,000 fols.
Le matériau composite d'isolation électrique selon llnvention a l'avantage de pouvoir être préparé par un procède d'injection ou par coulée gravitationnelle tout en présentant une rigidité diélectrique élevée, un faible coefficient d'expansion thermique, une faible porosité, une conductivité thermique relativement élevée, et, de manière avantageuse, également une faible permittivité diélectrique. En effet, le choix judicieux de la forme et la taille des charges, et de leurs teneurs respectives, a permis de trouver un équilibre entre ces propriétés a priori antinomiques. Le matériau composite d'isolation électrique selon l'invention peut présenter en outre une ou plusieurs caractéristiques additionnel lej suivantes : The composite electrical insulation material according to the invention has the advantage of being able to be prepared by an injection process or by gravitational casting while having a high dielectric strength, a low coefficient of thermal expansion, a low porosity, a thermal conductivity. relatively high, and advantageously also low dielectric permittivity. Indeed, the judicious choice of the shape and size of the fillers, and of their respective contents, made it possible to find a balance between these properties which are a priori contradictory. The composite electrical insulation material according to the invention may also have one or more of the following additional characteristics:
la deuxième charge inorganique micrométrique a un facteur de forme allant de 10 à 50 ,  the second micrometric inorganic filler has a form factor ranging from 10 to 50,
la deuxième charge inorganique micrométrique est choisie parmi BN et AI2O3, et de préférence parmi hBN et AI2O3 ;  the second micrometric inorganic charge is chosen from BN and AI2O3, and preferably from hBN and AI2O3;
la première charge Inorganique micrométrique est choisie parmi the first micrometric inorganic charge is chosen from
SiO2, AI2O3, AI(OH)3, CaO, MgO, CaCO3, et TiO2 ; SiO 2 , AI 2 O 3 , AI (OH) 3 , CaO, MgO, CaCO 3 , and TiO 2 ;
la teneur en charges va de 20 à 40% en volume, et de préférence de 25 à 35% en volume, par rapport au volume total du matériau composite d'isolation électrique ;  the content of fillers ranges from 20 to 40% by volume, and preferably from 25 to 35% by volume, relative to the total volume of the composite electrical insulation material;
le ratio volumique entre la première charge Inorganique micrométrique et la deuxième charge inorganique micrométrique va de 70/30 à 50/50 ;  the volume ratio between the first micrometric inorganic charge and the second micrometric inorganic charge ranges from 70/30 to 50/50;
la matrice est une matrice époxy de type dlglycldyléther, et de préférence une matrice époxy de type diglycidyléther de bisphénol A (DGEBA) ;  the matrix is an epoxy matrix of the dlglycldylether type, and preferably an epoxy matrix of the diglycidylether type of bisphenol A (DGEBA);
le matériau composite dlsolatlon électrique comprend en outre une troisième charge micrométrique, distincte de la première charge Inorganique micrométrique et de la deuxième charge inorganique micrométrique ;  the electrical dlsolatlon composite material further comprises a third micrometric charge, distinct from the first micrometric inorganic charge and from the second micrometric inorganic charge;
la première charge Inorganique micrométrique et/ou la deuxième charge inorganique micrométrique et/ou, lorsqu'elle est présente, la troisième charge micrométrique sont fonctionnalisées en surface ; le matériau composite d'isolation électrique se présente sous la forme d'un support isolant électriquement apte à maintenir en position un conducteur électrique dans un poste sous enveloppe métallique. Un autre objet de l'invention concerne un procédé de fabrication d'un matériau composite d'isolation électrique selon l'invention. Pour cela, le procédé de fabrication comprend les étapes suivantes . the first micrometric inorganic filler and / or the second micrometric inorganic filler and / or, when it is present, the third micrometric filler are functionalized at the surface; the electrical insulation composite material is in the form of an electrically insulating support capable of holding an electrical conductor in position in a station in a metallic envelope. Another object of the invention relates to a method of manufacturing a composite material of electrical insulation according to the invention. For this, the manufacturing process includes the following steps.
a. préparation d'un mélange rétlculable composé d'une résine époxy de type cycloaliphatique ou de type dlglycldylether, d'une première charge Inorganique micrométrique ayant un facteur de forme inférieur à 3, d'une deuxième charge inorganique micrometrique lamellaire ayant un facteur de forme allant de 3 à 100, et d'un agent de réticulation,  at. preparation of a crosslinkable mixture composed of an epoxy resin of cycloaliphatic type or of dlglycldylether type, of a first micrometric inorganic filler having a form factor less than 3, of a second lamellar micrometric inorganic filler having a form factor ranging from 3 to 100, and a crosslinking agent,
b. introduction dudit mélange rétlculable dans un moule, et  b. introduction of said reticulable mixture into a mold, and
c. réticulation du mélange rétlculable situé dans le moule.  vs. crosslinking of the crosslinkable mixture located in the mold.
Dans le cadre de l'invention, le « mélange rétlculable » s'entend comme le mélange d'une résiné époxy de type cycloaliphatique ou de type dlglycicyléther, des premières et deuxièmes chargea inorganiques micrométriques, telles que définies dans le cadre de l'invention, d'un agent de réticulation, et éventuellement d'une ou plusieurs charges additionnelles el/ou d'additif(3). Un tel mélange est avantageusement réticulé, grâce à un moyen de réticulation, comme explicité ci-après.  In the context of the invention, the "crosslinkable mixture" is understood to mean the mixture of an epoxy resin of the cycloaliphatic type or of the glycicyl ether type, of the first and second micrometric inorganic charges, as defined in the context of the invention , a crosslinking agent, and possibly one or more additional charges el / or additive (3). Such a mixture is advantageously crosslinked, thanks to a crosslinking means, as explained below.
Dans le cadre de l'invention, la * résine époxy » désigne un monomère ou un prépolymère époxy.  In the context of the invention, the “epoxy resin” designates an epoxy monomer or prepolymer.
Dans le cadre de l'invention, on entend par « agent de réticulation » un agent (c'est-à-dire un composé chimique) permettant de réticuler la résine époxy. Par exemple, l'agent de réticulation peut être un activateur ou un initiateur, ou un durcisseur en combinaison avec un activateur ou avec un initiateur, ou bien une combinaison d'un activateur, d'un Initiateur et d'un durcisseur. In the context of the invention, is meant pa r "crosslinker" an agent (that is to say a chemical compound) for crosslinking the epoxy resin. For example, the crosslinking agent can be an activator or initiator, or a hardener in combination with an activator or with an initiator, or a combination of an activator, an initiator and a hardener.
Le procédé selon llnvention est facile de mise en œuvre, et conduit à un maténau composite d'isolation éleetnque présentant une faible porosité, une rigidité diélectrique élevée, une faible permltivité diélectrique, un faible coefficient d'expansion thermique, et une conductivité thermique élevée. Le procédé selon llnvention peut présenter en outre une ou plusieurs caractéristiques additionnelles suivantes : The method according to the invention is easy to implement, and leads to a composite material of electrical insulation having a low porosity, a high dielectric strength, a low dielectric permltivity, a low coefficient of thermal expansion, and a high thermal conductivity. The method according to the invention may also have one or more of the following additional characteristics:
- le mélange réticulable a une viscosité allant de 6000 mPa.s a 15000 mPa.s, de préférence de 10000 mPa.s à 12000 mPas, mesurée a 80 °C selon la norme ISO 12058 ;  - The crosslinkable mixture has a viscosity ranging from 6000 mPa.s to 15000 mPa.s, preferably from 10000 mPa.s to 12000 mPas, measured at 80 ° C according to ISO standard 12058;
- l'agent de réticulation est un activateur, ou un Initiateur, ou un durcisseur en combinaison avec un activateur ou avec un Initiateur, ou bien une combinaison d'un activateur, d'un initiateur et d'un durcisseur ;  the crosslinking agent is an activator, or an initiator, or a hardener in combination with an activator or with an initiator, or else a combination of an activator, an initiator and a hardener;
l'Introduction du mélange réticulable dans le moule se fait par coulée gravitationnelle ou par Injection dans le moule ;  the introduction of the crosslinkable mixture into the mold is done by gravitational casting or by injection into the mold;
- la réticulation est réalisée par application d'un moyen de réticulation tel que du chauffage ou des UV ;  the crosslinking is carried out by application of a crosslinking means such as heating or UV;
- le mélange réticulable comprend en outre une troisième charge micrométrique.  - The crosslinkable mixture further comprises a third micrometric charge.
Dans le cadre de (Invention, un « moyen de réticulation » est un moyen physique permettant la réticulation du mélange réticulable, tel que le chauffage ou les UV.  In the context of (Invention, a “crosslinking means” is a physical means allowing the crosslinking of the crosslinkable mixture, such as heating or UV.
Un autre objet de l'invention concerne un poste sous enveloppe métallique (PSEM) comportant une enveloppe externe délimitant intérieurement une enceinte dans laquelle est monté un conducteur électrique haute tension à l'aide de supports Isolante électriques réalisés en un matériau composite d'isolation électrique selon llnvention, ou réalisés en un matériau électrique obtenus par le procédé selon llnvention.  Another object of the invention relates to a station in a metal envelope (PSEM) comprising an external envelope internally delimiting an enclosure in which is mounted a high voltage electrical conductor using electrical insulating supports made of a composite material of electrical insulation. according to llnvention, or made of an electrical material obtained by the method according to llnvention.
Diverses autres caractéristiques ressortent de la description faite ci- dessous en référence aux dessins annexés qui montrent, à titre d'exemples non limitatifs, des formes de réalisation de l'objet de l'Invention.  Various other characteristics will emerge from the description given below with reference to the appended drawings which show, by way of nonlimiting examples, embodiments of the object of the invention.
La Figure 1 est une vue schématique d'un matériau composite d'isolation électrique hors Invention, composé d'une matrice et de charges ayant un facteur de forme inférieur à 3. Les étoiles représentent des pointe chauds apparaissant à l'interface charge-matrice. La Figure 2 est une vue schématique d'un matériau composée d'isolation eiectrlque selon l'invention. Les étoiles représentent des points chauds apparaissant à l'interface charge-matrice. Les flèches représentent le transfert thermique. Figure 1 is a schematic view of a composite electrical insulation material outside the invention, composed of a matrix and of charges having a form factor of less than 3. The stars represent hot points appearing at the charge-matrix interface . Figure 2 is a schematic view of a composite insulation material according to the invention. The stars represent hot spots appearing at the charge-matrix interface. The arrows represent the heat transfer.
La Figure 3 est une vue en coupe d'un poste électrique sous enveloppe métallique comprenant un support isolant électriquement sous forme de cône.  Figure 3 is a sectional view of an electrical substation in a metal casing comprising an electrically insulating support in the form of a cone.
La Figure 4 est une vue en coupe d'un poste électrique sous enveloppe métallique comprenant un support isolant électriquement sous forme de « post-type ».  Figure 4 is a sectional view of an electrical substation in a metal casing comprising an electrically insulating support in the form of a "post-type".
L'Invention concerne un matériau composite d'isolation électrique 1 adapté à être utilise pour former des supports Isolants électriquement pour maintenir en position les conducteurs présents dans les PSEM. Le matériau composite d'isolation électrique est composé d'une matrice 2 dans laquelle est dispersé un mélange de charges inorganiques micrométriques.  The invention relates to a composite electrical insulation material 1 adapted to be used to form electrically insulating supports to hold in position the conductors present in the SEMCs. The electrical insulation composite material is composed of a matrix 2 in which a mixture of micrometric inorganic charges is dispersed.
La matrice 2 est formée par la réticulation d'une résine époxy de type cycloallphatique ou d'une résine époxy de type diglycidyléther. De préférence, la matrice 2 est une matrice de type diglycidyléther, et en particulier diglycidyléther de blsphénol A.  The matrix 2 is formed by the crosslinking of an epoxy resin of the cycloallphatic type or of an epoxy resin of the diglycidyl ether type. Preferably, the matrix 2 is a matrix of diglycidyl ether type, and in particular diglycidyl ether of blsphenol A.
Le matériau composite d'isolation électrique 1 comprend également un mélange d'au moins deux charges inorganiques micrométriques distinctes. La présence de ces deux charges permet d'augmenter la conductivité thermique du matériau composite d'isolation électrique 1 ainsi que sa tenue électrique.  The electrical insulation composite material 1 also comprises a mixture of at least two distinct micrometric inorganic fillers. The presence of these two charges makes it possible to increase the thermal conductivity of the composite electrical insulation material 1 as well as its electrical resistance.
La première charge Inorganique micrométrique 3 a un facteur de forme inférieur à 3, et de préférence Inférieur ou égal à 2, voire inférieur ou égal a 1,5.  The first micrometric inorganic filler 3 has a form factor of less than 3, and preferably less than or equal to 2, or even less than or equal to 1.5.
La première charge Inorganique micrométrique 3 de facteur de forme inférieur à 3 peut être de toute forme, et en particulier sphérique ou quasi sphérique.  The first micrometric inorganic charge 3 with a form factor of less than 3 can be of any shape, and in particular spherical or almost spherical.
Toute charge Inorganique micrométrique avec un facteur te forme inférieur à 5, ayant des propriétés d'isolation électrique et de conductivité thermique, peut convenir en tant que première charge 3 dans le cadre de llnvention. A titre d'exemples de première charge inorganique micrométrique 3, on peut citer la silice (SlOz), l'alumine (AI2O3), Itiydroxyde d'aluminium (AI(OH)3), l'oxyde de calcium (CaO), l'oxyde de magnésium (MgO), le carbonate de calaum (CaC03), et le dioxyde de titane CTIO2). De préférence, la première charge inorganique micrométrique 3 est choisie parmi la silice (S1O2) ou l'alumine (AI2O3). Any micrometric inorganic filler with a factor of less than 5, having electrical insulation and thermal conductivity, may be suitable as the first charge 3 in the context of the invention. As examples of the first micrometric inorganic filler 3, mention may be made of silica (SlOz), alumina (AI 2 O 3 ), aluminum hydroxide (AI (OH) 3 ), calcium oxide (CaO ), magnesium oxide (MgO), calaum carbonate (CaC0 3 ), and titanium dioxide CTIO 2 ). Preferably, the first micrometric inorganic filler 3 is chosen from silica (S1O 2 ) or alumina (AI 2 O 3 ).
Le matériau composite d'isolation électrique 1 comprend de préférence une seule charge de type première charge inorganique micrumétrique 3. Néanmoins, >e matériau composite d'isolation électrique 1 peut comprendre plusieurs charges de type première charge inorganique micrométrique 3, et en particulier deux.  The composite electrical insulation material 1 preferably comprises a single charge of the first micrumetric inorganic charge type 3. Nevertheless, the composite electrical insulation material 1 can comprise several charges of the first micrometric inorganic charge type 3, and in particular two.
La deuxième charge inorganique micrométrique 4 est de type lamellaire et a un facteur de forme allant de 3 à 100, et de préférence de 10 à 50. La deuxième charge Inorganique micrométrique 4 est donc ni de type sphérique, ni sous forme d'aiguille.  The second micrometric inorganic filler 4 is of the lamellar type and has a form factor ranging from 3 to 100, and preferably from 10 to 50. The second micrometric inorganic filler 4 is therefore neither of the spherical type nor in the form of a needle.
Toute charge Inorganique micrométrique lamellaire avec un facteur de forme allant de 3 à 100 peut convenir dans le cadre de l'invention en tant que deuxième charge 4. A titre d'exemples de deuxième charge inorganique micrométrique 4, on peut citer le nitrure de bore (BN) en particulier sous forme hexagonale (hBN), ou l'alumine (AI2O3). De préférence, la deuxième charge inorganique micrométrique 4 et choisie parmi le nitrure de bore sous forme hexagonale (hBN) ou et l'alumine (AI2O3). Any inorganic micrometric lamellar filler with a form factor ranging from 3 to 100 may be suitable in the context of the invention as a second filler 4. As examples of a second micrometric inorganic filler 4, boron nitride may be mentioned (BN) in particular in hexagonal form (hBN), or alumina (AI 2 O 3 ). Preferably, the second micrometric inorganic filler 4 and chosen from boron nitride in hexagonal form (hBN) or and alumina (AI 2 O 3 ).
Avantageusement, la deuxième charge inorganique micrométrique 4 lamellaire ne se présente pas sous forme d'aggregat Dans le cas contraire, les aggrégats sont de préférence cassés lors de la préparation du matériau dlsolation électrique 1, comme détaillé U-dessous.  Advantageously, the second micrometric inorganic charge 4 lamellar is not in the form of an aggregate. Otherwise, the aggregates are preferably broken during the preparation of the electrical insulation material 1, as detailed below.
Le matériau composite d'isolation électrique 1 comprend de préférence une seule charge de type deuxième charge inorganique micrométrique lamellaire 4. Néanmoins, le matériau composite dlsolation électrique 1 peut comprendre plusieurs charges de type deuxieme charge inorganique micrométrique 4, et en particulier deux. The composite electrical insulation material 1 preferably comprises a single charge of the second inorganic micrometric lamellar charge type 4. Nevertheless, the composite electrical insulation material 1 can comprise several charges of the second micrometric inorganic charge type 4, and in particular two.
Le matériau composite d'isolation électrique ?. comprend de 15 à 45% en volume de charges par rapport au volume total du matériau composite d'isolation électrique 1, et de préférence de 20 à 40% en volume, et mieux encore de 25 à 35% en volume. Cette teneur s'entend comme la teneur totale en charges, c'est-à-dire la teneur en première charge Inorganique micrométrique 3, en deuxième charge Inorganique micrométrique lamellaire 4 et en charges additionnelles lorsque celles-ci sont présentes, comme exposé ci-après.  The composite material of electrical insulation? comprises from 15 to 45% by volume of charges relative to the total volume of the composite electrical insulation material 1, and preferably from 20 to 40% by volume, and better still from 25 to 35% by volume. This content is understood as the total content of fillers, that is to say the content of first micrometric inorganic filler 3, of second micrometric inorganic lamellar filler 4 and of additional fillers when these are present, as set out below. after.
Les première et deuxième charges inorganiques micrométriques sont présentes dans le matériau composite d'isolation électrique 1 dans un ratio volumique allant de 95/05 à 40/60, et de préférence allant de 70/30 à 50/50.  The first and second micrometric inorganic fillers are present in the electrical insulation composite material 1 in a volume ratio ranging from 95/05 to 40/60, and preferably ranging from 70/30 to 50/50.
Selon un mode de réalisation particulier de l'invention, la première charge Inorganique micrométrique 3 est choisie parmi l'alumine (AI2O5) et la silice (Si<¼), et la deuxième charge Inorganique micrométrique lamellaire 4 est choisie parmi le nltrure de bore sous forme hexagonale (hBN) et l'alumine (AI2O3).  According to a particular embodiment of the invention, the first micrometric inorganic filler 3 is chosen from alumina (AI2O5) and silica (Si <¼), and the second micrometric lamellar inorganic filler 4 is chosen from boron nltride in hexagonal form (hBN) and alumina (AI2O3).
Selon un mode de réalisation particulier de l'invention, la résine époxy est une résine époxy de type diglyddyléther, et par exemple une résine de type diglyddyléther de bisphénol A, la première charge inorganique micrométrique 3 est choisie parmi l'alumine (AI2O3) et la silice (Si02), et la deuxième charge Inorganique micrométrique lamellaire 4 est choisie parmi le nltrure de bore sous forme hexagonale (hBN) et l'alumine (AI2O3). According to a particular embodiment of the invention, the epoxy resin is an epoxy resin of the diglyddylether type, and for example a resin of the diglyddylether type of bisphenol A, the first micrometric inorganic filler 3 is chosen from alumina (AI2O3) and silica (Si0 2 ), and the second inorganic micrometric lamellar filler 4 is chosen from boron nltride in hexagonal form (hBN) and alumina (AI2O3).
Tel que cela est représenté à la Mgure 2, la présence de la deuxième charge inorganique micrométrique lamellaire 4 permet d'augmenter les chemins conducteurs thermiques dans le matériau, idéalement par contact entre les particules mais également en réduisant la distance entre les charges au sein de la matrice jusqu'à un quasi contact, œ qui permet de réduire considérablement les dommages subis par le matériau dûs à l'apparition de points chauds. La première charge Inorganique micrométrique 3 ayant un facteur de forme Inférieur à 3 permet de combler les espaces vides entre les deuxièmes charges inorganiques micrométriques lamellaires 4, et ainsi améliorer encore la conductivité thermique du matériau. La deuxième charge Inorganique micrométrique lamellaire 4 permet également d'améliorer la rigidité diélectrique du matériau, et notamment en comparaison des charges inorganiques micrométrfques sous forme d'aiguille en faisant une barrière physique à la propagation d'électron dans le matériau plus grande en raison de leur forme. As shown in Figure 2, the presence of the second inorganic micrometric lamellar charge 4 makes it possible to increase the thermal conductive paths in the material, ideally by contact between the particles but also by reducing the distance between the charges within the matrix to a virtual contact, œ which considerably reduces the damage to the material due to the appearance of hot spots. The first inorganic charge micrometric 3 having a form factor Less than 3 makes it possible to fill the empty spaces between the second inorganic micrometric lamellar fillers 4, and thus further improve the thermal conductivity of the material. The second inorganic micrometric lamellar charge 4 also makes it possible to improve the dielectric rigidity of the material, and in particular in comparison with the micrometrical inorganic charges in the form of needle by making a physical barrier to the propagation of electron in the material greater due to their shape.
Selon un mode de réalisation de l'invention, le matériau composite d'isolation électrique 1 comprend en outre une ou plusieurs autres charges, différentes de la première et de la deuxième charges inorganiques micrométriques J et 4, nommées charges additionnelles. Selon ce mode de réalisation, œs charges additionnelles sont micrométriques et peuvent être des charges organiques ou Inorganiques, de toute forme. A titre d'exemples de charges additionnelles, on peut citer des fibres de verre. Selon ce mode de réalisation, les charges additionnelles ne représentent pas plus de 10% en volume, et de préférence pas plus de 5%, par rapport au volume total du matériau composite d'isolation électrique 1. Lorsqu'elles sont présentes, ces charges additionnelles permettent d'améliorer des propriétés mécaniques ou physico-chimiques suivant les applications, par exemple hydrophobicité, résistance à la torsion, à la compression, à la flamme.  According to one embodiment of the invention, the composite electrical insulation material 1 also comprises one or more other charges, different from the first and from the second micrometric inorganic charges J and 4, called additional charges. According to this embodiment, these additional charges are micrometric and can be organic or inorganic charges, of any shape. As examples of additional fillers, mention may be made of glass fibers. According to this embodiment, the additional charges do not represent more than 10% by volume, and preferably not more than 5%, relative to the total volume of the composite electrical insulation material 1. When present, these charges additional allow to improve mechanical or physicochemical properties according to the applications, for example hydrophobicity, resistance to torsion, compression, flame.
Dans le cadre de l'invention, une ou plusieurs charges (c'est-à-dire la première charge Inorganique micrométrique 3, et/ou la deuxième charge Inorganique micrométrique lamellaire 4, et/ou la uu les charges additionnelles lorsque celles-ci sont présentes) peuvent être fonctionnalisées en surface. Cette fonctionnallsatior permet en particulier d'améliorer la compatibilité des chargea avec la matrice, et alors d'améliorer la conductivité thermique du matériau et le coefficient d'expansion thermique. Les fbnctionnalisations de surface des charges sont usuelles dans l'état de l'art et ne seront pas détaillées ici. Le matériau composite d'isolation électrique 1 peut également comprendre des additifs tels que des plastifiants. In the context of the invention, one or more charges (that is to say the first micrometric inorganic charge 3, and / or the second micrometric lamellar inorganic charge 4, and / or uu the additional charges when these are present) can be functionalized on the surface. This functionalallows in particular to improve the compatibility of the charges with the matrix, and then to improve the thermal conductivity of the material and the coefficient of thermal expansion. The surface functionalizations of the charges are usual in the state of the art and will not be detailed here. The composite electrical insulation material 1 can also include additives such as plasticizers.
Avantageusement, le matériau composite d'isolation électrique 1 selon l'invention est faiblement poreux, et de préférence ne contient pas de porosités. En effet, une forte porosité empêcherait une utilisation comme Isolant électrique pour la haute tension.  Advantageously, the composite electrical insulation material 1 according to the invention is weakly porous, and preferably does not contain porosities. Indeed, high porosity would prevent use as an electrical insulator for high voltage.
Le matériau composite d'isolation électrique 1 selon l'invention est préparé par introduction d'un mélange réticulable dans un moule, suivie d'une étape de réticulation.  The composite electrical insulation material 1 according to the invention is prepared by introducing a crosslinkable mixture into a mold, followed by a crosslinking step.
La première étape consiste en la préparation d'un mélange réticulable. Pour cela, une résine époxy de type cycloaliphatique ou une de type dlglycidyléther, et notamment une résine époxy de type dlglyddyléther de btsphénol A. la première et la deuxième charges inorganiques micrométriques 3 et 4 telles que définies cl-dessus, et un agent de réticulation sont mélangés selon toute technique connue de l'homme de l'art. Lorsque le mélange comprend des charges additionnelles et/ou des additifs, ceux-ci sont incorporés au mélange réticulable lors de cette première étape.  The first step is to prepare a crosslinkable mixture. For this, an epoxy resin of cycloaliphatic type or one of dlglycidylether type, and in particular an epoxy resin of dlglyddylether type of btsphenol A. the first and second micrometric inorganic fillers 3 and 4 as defined above, and a crosslinking agent are mixed according to any technique known to those skilled in the art. When the mixture comprises additional fillers and / or additives, these are incorporated into the crosslinkable mixture during this first step.
Selon un mode de réalisation particulier, un prémélange résine époxy - charges et un prémélange agent de réticulation - charges peuvent être préparés puis mis en contact afin de préparer le mélange réticulable.  According to a particular embodiment, an epoxy resin - fillers premix and a crosslinking agent - fillers premix can be prepared and then brought into contact in order to prepare the crosslinkable mixture.
Selon un premier mode de réalisation de l'invention, la deuxième charge Inorganique micrométrique 4 lamellaire utilisée ne se présente pas sous forme d'aggrégat. Selon un second mode de réalisation de l'invention, la deuxième charge inorganique micrométrique 4 lamellaire utilisée se présente sous forme d'aggrégat Selon ce deuxième mode de réalisation, le procédé comprend alors avantageusement une étape pendant laquelle les aggrégate sont cassés, soit en amont de la préparation du mélange durdssable, soit pendant sa préparation. Des méthodes pour casser les aggrégats de charges lamellaires sont bien connues dans l'état de l'art et ne seront pas détaillées ici. Le mélange rétlculable comprend un agent de réticulation. Dans le cadre de l'Invention, l'agent de réticulation peut être un activateur, ou un initiateur, ou un durcisseur en combinaison d'un activateur ou avec un initiateur, ou une combinaison d'un activateur, d'un Initiateur et d'un durcisseur. Dans le cadre de l'invention, les activateurs, les durcisseurs et les Initiateurs pouvant être utilisés pour la réticulation de la résine époxy de type cycloaliphatique ou de type diglydcyléther sont ceux habituellement employés dans l'état de l'art. A titre d'exemples de durcisseurs, on peut citer les dlamines et les anhydrides. According to a first embodiment of the invention, the second micrometric inorganic 4 lamellar filler used is not in the form of an aggregate. According to a second embodiment of the invention, the second inorganic micrometric 4-lamellar charge used is in the form of an aggregate. According to this second embodiment, the method then advantageously comprises a step during which the aggregates are broken, either upstream. of the preparation of the durdssable mixture, that is during its preparation. Methods for breaking the aggregates of lamellar charges are well known in the state of the art and will not be detailed here. The crosslinkable mixture comprises a crosslinking agent. In the context of the invention, the crosslinking agent may be an activator or initiator or a curing agent in combination with an activator or an initiator, or a comb i bination of an activator, an initiator and a hardener. Within the framework of the invention, the activators, hardeners and initiators which can be used for the crosslinking of the epoxy resin of cycloaliphatic type or of diglydcylether type are those usually employed in the state of the art. As examples of hardeners, mention may be made of dlamines and anhydrides.
Le mélange réticulable doit avoir une viscosité permettant la fabrication par le biais d'une coulée gravitationnelle sous vide ou par gélification sous pression automatisée. Avantageusement, le mélange réticulable obtenu a une viscosité appartenant a la gamme allant de 6000 mPa.s à 15000 mPa.s, de préférence allant de 10000 mPa.s à 12000 mPa.s mesurée à 80 °C selon la norme ISO 12058. Avantageusement, le mélange réticulable obtenu a une viscosité appartenant a la gamme allant de 15000 mPa.s à 29000 mPa.s, de préférence de 18000 mPa.s à 24000 mPa.s, mesurée à 50 °C selon la norme ISO 12058.  The crosslinkable mixture must have a viscosity allowing manufacture by gravitational casting under vacuum or by gelling under automated pressure. Advantageously, the crosslinkable mixture obtained has a viscosity belonging to the range going from 6000 mPa.s to 15000 mPa.s, preferably going from 10000 mPa.s to 12000 mPa.s measured at 80 ° C according to the ISO 12058 standard. , the crosslinkable mixture obtained has a viscosity belonging to the range from 15,000 mPa.s to 29,000 mPa.s, preferably from 18,000 mPa.s to 24,000 mPa.s, measured at 50 ° C according to ISO 12058 standard.
Dans le cadre de l'invention, le contrôle de la viscosité du mélange réticulable est Important, car une viscosité trop élevée conduirait à un mélange réticulable comportant des bulles, et donc un matériau final comportant des défauts et/ou poreux. Du plus, une viscosité élevée rendrait le mélange réticulable difficile à introduire dans le moule par injection ou par coulée gravitationnelle, A l'opposé une viscosité trop faible réduirait l'efficacité du procédé de fabrication par gélification sous pression automatisée.  In the context of the invention, the control of the viscosity of the crosslinkable mixture is important, because too high a viscosity would lead to a crosslinkable mixture comprising bubbles, and therefore a final material comprising defects and / or porous. In addition, a high viscosity would make the crosslinkable mixture difficult to introduce into the mold by injection or by gravitational casting. Conversely, a too low viscosity would reduce the efficiency of the manufacturing process by gelation under automated pressure.
Tel que cela est connu de l'homme de l'art, plus la teneur en charges e.5t élevée, plus le mélange réticulable a une viscosité élevée. Ainsi, 11 est habituellement difficile d'obtenir un matériau composite d'isolation électrique à faible porosité par introduction dans un moule de résines chargées ayant une forte teneur en charges (en particulier, dans le cas de charges lamellaires, une teneur d'au moins 15% en volume par rapport au volume total du mélange réticulable). De manière surprenante dans le cadre de l'invention, l'augmentation de la viscosité due à ces taux élevés en charges est limitée, ce qui permet la coulée gravitationnelle du mélange réticulable ou son injection dans un moule. Le Demandeur a découvert que les mélanges réticulables avaient une rhéologie adaptée pour être mis en œuvre par coulée gravitationnelle, voire pour pouvoir être Injectés dans un moule, en choisissant judicieusement la nature et la forme de ces charges et leurs proportions, et conduisent à un matériau peu poreux. Cela est d'autant plus surprenant que la presence de charges lamellaires à ces taux éleves est connue pour augmenter habituellement la viscosité du mélange de sorte que cette mise en œuvre est difficile, voire impossible. As is known to those skilled in the art, the higher the filler content e.5t, the higher the crosslinkable mixture has a viscosity. Thus, it is usually difficult to obtain a composite material of electrical insulation with low porosity by introduction into a mold of charged resins having a high content of fillers (in particular, in the case of fillers lamellar, a content of at least 15% by volume relative to the total volume of the crosslinkable mixture). Surprisingly in the context of the invention, the increase in viscosity due to these high levels of fillers is limited, which allows the gravitational casting of the crosslinkable mixture or its injection into a mold. The Applicant has discovered that the crosslinkable mixtures had a rheology adapted to be implemented by gravitational casting, or even to be able to be injected into a mold, by judiciously choosing the nature and the shape of these fillers and their proportions, and lead to a material. not very porous. This is all the more surprising since the presence of lamellar fillers at these high rates is known to usually increase the viscosity of the mixture so that this implementation is difficult, if not impossible.
Avantageusement, la répartition des charges dans le mélange réticulable est homogène.  Advantageously, the distribution of the charges in the crosslinkable mixture is homogeneous.
La deuxième étape du procédé de fabrication selon l'invention consiste à Introduire le mélange réticulable, obtenu à la première étape, dans un moule ayant la forme désirée. Cette introduction peut être réalisée selon toute technique connue de l'homme de l'art. De préférence, cette Introduction dans le moule est réalisée soit par coulée gravitationnelle, soit par injection selon toute technique connue dans l'état de l'art.  The second step of the manufacturing process according to the invention consists in introducing the crosslinkable mixture, obtained in the first step, into a mold having the desired shape. This introduction can be carried out according to any technique known to those skilled in the art. Preferably, this introduction into the mold is carried out either by gravitational casting or by injection according to any technique known in the state of the art.
La troisième étape consiste à néticuler le mélange réticulable préalablement introduit dans le moule. Cette étape peut être réalisée selon toute technique connue de l'homme de l'art. Selon un mode de réalisation particulier, cette étape de réticulation peut être réalisée en présence d'un moyen de réticulation, comme le chauffage ou les UV par exemple.  The third stage consists in cross-linking the crosslinkable mixture previously introduced into the mold. This step can be carried out according to any technique known to those skilled in the art. According to a particular embodiment, this crosslinking step can be carried out in the presence of a crosslinking means, such as heating or UV for example.
Lorsque la réticulation est réalisée sans moyen de réticulation, le temps de prise est avantageujement supérieur ou égal à une heure.  When crosslinking is carried out without crosslinking means, the setting time is advantageously greater than or equal to one hour.
Enfin, la dernière étape du procédé consiste à démouler la structure obtenue et réalisée en matériau composite d'isolation électrique 1, selon toute technique connue dans l'état de l'art. La structure réalisée en matériau composite d'isolation électrique 1 ainsi obtenue est facile à préparer par injection ou coulée gravitationnelle, a de bonnes propriétés de conductivité thermique et d'isolation électrique, un faible coefficient d'expansion thermique, et une haute rigidité diélectrique. Avantageusement, la structure réalisée en matériau composite d'isolation électrique 1 ainsi obtenue a également une faible permittivité diélectrique. Finally, the last step of the method consists in demolding the structure obtained and made of composite material of electrical insulation 1, according to any technique known in the state of the art. The structure made of composite material of electrical insulation 1 thus obtained is easy to prepare by injection or gravitational casting, has good thermal conductivity and electrical insulation properties, a low coefficient of thermal expansion, and a high dielectric strength. Advantageously, the structure made of composite electrical insulation material 1 thus obtained also has a low dielectric permittivity.
Avantageusement, le matériau composite d'isolation électrique obtenu par le procédé selon l'invention a une faible porosité, et de préférence n'est pas poreux. Selon un mode particulier de réalisation, Il est possible de diminuer encore la porosité du matériau tomposite d'isolation électrique 1, voire de la supprimer totalement, en réalisant un ou plusieurs dégazages du mélanqe réticulable, avant son Introduction dans le moule. Par exemple, æ dégazage peut être réalisé sous pression réduite d'une dizaine de millibars, de préférence en mélangeant ledit mélange réticulable.  Advantageously, the composite electrical insulation material obtained by the method according to the invention has a low porosity, and preferably is not porous. According to a particular embodiment, it is possible to further reduce the porosity of the tomposite material of electrical insulation 1, or even to eliminate it completely, by carrying out one or more degassings of the crosslinkable mixture, before its introduction into the mold. For example, degassing can be carried out under reduced pressure of ten millibars, preferably by mixing said crosslinkable mixture.
Tel que cela ressort aux Figures 3 et 4, l'invention concerne également un poste sous enveloppe métallique 5 comportant une enveloppe externe 6 délimitant intérieurement une enceinte 7 dan^ laquelle est montée un conducteur électrique haute tension 8 maintenu en position par des supports Isolants électriquement 9 réalisés en un matériau composite d'isolation électrique 1 selon l'Invention.  As can be seen in Figures 3 and 4, the invention also relates to a station in a metal casing 5 comprising an external casing 6 internally delimiting an enclosure 7 dan ^ which is mounted a high voltage electrical conductor 8 held in position by electrically insulating supports 9 made of a composite electrical insulation material 1 according to the invention.
Selon un exemple préféré de réalisation représenté aux Figure 3 et 4, l'enveloppe métallique externe G présente une forme cylindrique. Cet exemple n'est pas limitatif.  According to a preferred embodiment shown in Figures 3 and 4, the outer metal casing G has a cylindrical shape. This example is not limitative.
Un conducteur électrique haute tension 8 de tout type connu en sol est monte à llnterieur de l'enveloppe métallique externe G. Le conducteur électrique haute tension 8 est de forme tubulaire dans l'exemple de réalisation représenté aux Figures 3 et 4.  A high-voltage electrical conductor 8 of any known type on the ground is mounted inside the external metal casing G. The high-voltage electrical conductor 8 is tubular in the embodiment shown in FIGS. 3 and 4.
Le conducteur électrique haute tension 8 est maintenu au centre de l'enveloppe métallique externe 6 à l'aide de supports isolants électriquement 9, tels que des entretoises réalisées dans les exemples illustrés par des cônes (Figure 3) ou des « post-types * (Figure 4). Bien que non illustrées, d'autres formes pourraient être envisagées, Quelle que soit leur forme, les supports isolants électriquement 9 sont réalisés en un matériau composite d'isolation électrique 1 conforme à l'invention. The high voltage electrical conductor 8 is held in the center of the external metal casing 6 using electrically insulating supports 9, such as spacers produced in the examples illustrated by cones (Figure 3) or "post-types * (Figure 4). Although not illustrated, other forms could be envisaged, whatever their form, the electrically insulating supports 9 are made of a composite material of electrical insulation 1 according to the invention.
Grâce à l'étanchéité de l'enveloppe externe métallique 6, le volume Interne de l'enceinte 7 est rempli d'un fluide isolant, typiquement un gaz isolant tel que SFe.  Thanks to the tightness of the metallic external envelope 6, the internal volume of the enclosure 7 is filled with an insulating fluid, typically an insulating gas such as SFe.
Les Exemples ci-après permettent d'illustrer l'invention mais n'ont aucun caractère limitatif. The examples below illustrate the invention but are in no way limiting.
Un matériau composite dlsolation électrique A selon l'intention et quatre matériaux dlsolation électrique hors Invention (B (sans charge)- C (avec uniquement une charge ayant un facteur de forme Inférieur à 3), D (avec uniquement une charge lamellaire) et E (avec un ratio volumique entre la charge de facteur de forme inférieur à 3 et la charge lamellaire hors Invention) ont été préparés (voir Tableau 1). La teneur totale en chargea du matériau composite D n'a pas pu être augmentée jusqu'à 37% volumique en raison de la trop grande viscosité du mélange réticulable. A composite material of electrical insulation A according to the intention and four materials of electrical insulation except Invention (B (without load) - C (with only a load having a form factor lower than 3), D (with only a lamellar load) and E (with a volume ratio between the form factor charge less than 3 and the lamellar charge outside the invention) were prepared (see Table 1). The total charge content a of the composite material D could not be increased until 37% by volume due to the too high viscosity of the crosslinkable mixture.
Afin de réaliser les matériaux A à E, la résine époxy utilisée est la résine époxy de type diglycldyléther de bisphénol A (DGfcBA) fournie par Huntsman sous la référence CY 5925. Les charges utilisées dans les différents matériaux composites sont une alumine micrométrique fournie par la société Imerys sous la référence Alodur®WSK, et le nltrure de bore hexagonal hBN fourni par la joclété Momentlve sous la référence PT120. Un durcisseur en tant qu'agent de réticulation a également été utilise : un anhydride commercialisé sous la référence HY5925 par la société Huntsman. In order to produce materials A to E, the epoxy resin used is the epoxy resin of the diglycldylether type of bisphenol A (DGfcBA) supplied by Huntsman under the reference CY 5925. The fillers used in the various composite materials are a micrometric alumina supplied by the Imerys under the reference Alodur®WSK, and the hexagonal boron nltride hBN supplied by Momentlve under the reference PT120. A hardener as crosslinking agent was also used: an anhydride sold under the reference HY5925 by the company Huntsman.
Les matériaux A à E sont préparés comme suit. Les charges sont séchées à 80 °C sous vide primaire pendant 24h avant utilisation. Un prémélange résine époxy - charges et durcisseur - charges est effectué dans le but de faciliter la dispersion des charges. Les prémélanges sont alors mélangés dans des proportions telles que le rapport massique résine époxy : durcisseur est de 100;80. L'ensemble des mélanges est réalise à l'aide d'un mélangeur planétaire SpeedMixer DAC 400 à 2500 rpm. Le mélange réticuldble est ensuite dëgazé sous vide primaire à S0°C pendant lh00, puis est ensuite coulé par coulée gravltionnelle dans un moule fermé en aluminium dont la surface a été traitée avec un agent de démoulage. Le mélange est enfin réticule en chauffant suivant le cycle de température suivant r 4 h à 100 °C puis 8 h à 140 °C.  Materials A to E are prepared as follows. The charges are dried at 80 ° C under primary vacuum for 24 hours before use. An epoxy resin - fillers and hardener - fillers premix is made in order to facilitate the dispersion of the fillers. The premixes are then mixed in proportions such that the mass ratio of epoxy resin: hardener is 100; 80. All the mixes are carried out using a SpeedMixer DAC 400 planetary mixer at 2500 rpm. The crosslinkable mixture is then degassed under primary vacuum at S0 ° C for 1 hour, then is then poured by gravltional casting into a closed aluminum mold, the surface of which has been treated with a release agent. The mixture is finally crosslinked by heating according to the temperature cycle following r 4 h at 100 ° C then 8 h at 140 ° C.
Les propriétés des différents matériaux A à D ont été évaluées : viscosité (mesurée a 50 °C selon la norme ISO 12058), rigidité diélectrique (mesurée selon la norme ISO 60243-1), conductivité thermique (mesurée selon la norme ISO 8894) et le coefficient d'expansion thermique. Le coefficient d'expansion thermique (CTE) a été déterminé à l'aide d'une TMA (Thermomechanlcal Analyser) Q400 TA Instruments de 40 °C à 170 °C. La force appliquée par la sonde d'expansion en quarte est de 5 mN et la rampe de température est de 3 uC/min. La mesure est faite sous azote. Les courbes exploitées sont celles obtenues en 2ème montée en température. Les résultats obtenus sont résumés dans le Tableau 2. Le matériau E a été utilisé pour illustrer l'importance des ratios entre charges et seules les valeurs de rigidité électrique et de conductivité thermique ont été évaluées. The properties of the different materials A to D were evaluated: viscosity (measured at 50 ° C according to ISO 12058 standard), dielectric strength (measured according to ISO 60243-1), thermal conductivity (measured according to ISO 8894 standard) and the coefficient of thermal expansion. The coefficient of thermal expansion (CTE) was determined using a TMA (Thermomechanlcal Analyzer) Q400 TA Instruments from 40 ° C to 170 ° C. The force applied by the quadrant expansion probe is 5 mN and the temperature ramp is 3 u C / min. The measurement is made under nitrogen. The curves used are those obtained in the 2nd temperature rise. The results The results obtained are summarized in Table 2. The material E was used to illustrate the importance of the ratios between charges and only the values of electrical rigidity and thermal conductivity were evaluated.
La viscosité des mélanges réticulables est impactée par la présence et la nature des charges. Le mélange rëticulable B sans charge a la plus faible viscosité. Cette viscosité est plus élevée dans le mélangé C en raison de la présence de d'alumine polydisperse. La viscosité lorsque le mélange rëticulable ne comporte que hBN en tant que charge est très élevée, de sorte que la teneur totale dans le mélange D est de 17%. En revanche, le mélange rëticulable A selon l'invention a une teneur totale élevée en charges, et un ratio en charge alumine hBN de 86,5/13,5, tout en ayant une viscosité permettant sa mise en œuvre. The viscosity of crosslinkable mixtures is affected by the presence and nature of the fillers. The crosslinkable mixture B without filler has the lowest viscosity. This viscosity is higher in Mixed C due to the presence of polydisperse alumina. The viscosity when the crosslinkable mixture contains only hBN as a filler is very high, so that the total content in mixture D is 17%. On the other hand, the crosslinkable mixture A according to the invention has a high total content of fillers, and an alumina load ratio hBN of 86.5 / 13.5, while having a viscosity allowing its implementation.
Le matériau composite A selon l'invention a une rigidité diélectrique analogue à celle du matériau composite C hors Invention, et sensiblement inférieure à celle du matériau B hors Invention. L'ajout de charge lamellaire dans le matériau composite A selon l'Invention nlmpacte pas de manière négative la rigidité diélectrique. Le matériau composite E a aussi une rigidité diélectrique équivalente au matériau composite C et le peu de charge de type lamellaire semble n'avoir aucun impact sur cette propriété. La conductivité thermique est plus élevée dans le matériau composite A selon l'invention comparé à tous les matériaux composites hors invention testés (conductivité thermique augmentée d'au moins 25%). La conductivité thermique du matériau E ejt très légèrement supérieure à celle du matériau C et se place dans la marge d'erreur de celui-ci. Le faible ajout de charge lamellaire dans le matériau E semble de ce fait Insuffisant pour que celle-ci soit en quantité nécessaire lui permettant un impact positif sur cette propriété. The composite material A according to the invention has a dielectric strength similar to that of the composite material C outside the invention, and substantially lower than that of the material B outside the invention. The addition of lamellar charge in the composite material A according to the invention does not negatively affect the dielectric strength. The composite material E also has a dielectric strength equivalent to the composite material C and the low charge of the lamellar type seems to have no impact on this property. The thermal conductivity is higher in the composite material A according to the invention compared to all the composite materials outside the invention tested (thermal conductivity increased by at least 25%). The thermal conductivity of the material E is very slightly higher than that of the material C and falls within the margin of error of the latter. The small addition of lamellar charge in the material E therefore appears to be insufficient for the latter to be in sufficient quantity allowing it to have a positive impact on this property.
Le coefficient d'expansion thermique est plus faible pour le matériau composite A selon llnvention, comparé aux matériaux B, C et D hors Invention (diminution jusqu'à 50%).  The coefficient of thermal expansion is lower for the composite material A according to the invention, compared to materials B, C and D outside the invention (reduction up to 50%).
Comparé aux matériaux B-E hors Invention, le matériau composite A selon l'invention permet d'allier une rigidité diélectrique satisfaisante, une conductivité thermique élevée, et un faible coefficient d'expansion thermique tout en étant facile de mise en œuvre grâce à une viscosité contrôlée du mélange réticulable. De plus, le matériau composite A a une très faible porosité.  Compared with BE materials outside the invention, the composite material A according to the invention makes it possible to combine satisfactory dielectric rigidity, high thermal conductivity, and a low coefficient of thermal expansion while being easy to use thanks to a controlled viscosity. of the crosslinkable mixture. In addition, the composite material A has a very low porosity.
L'Invention n'est pas limitée aux exemples décrite et représentés car diverses modifications peuvent y être apportées sans sortir de son cadre.  The invention is not limited to the examples described and shown since various modifications can be made thereto without departing from its scope.

Claims

REVENDICATIONS
1 - Matériau composite d'isolation électrique (I) comprenant une matrice (2) époxv de type cycloaliphatique ou de type dlglycldyléther, et de 15 à 45% en volume de charges par rapport au volume total de matériau composite d'isolation électrique (1), caractérisé en ce que ledit matériau composite d'isolation électrique (1) comprend une première charge inorganique micrométrique (3) ayant un facteur de forme inférieur à 5 et une deuxième charge inorganique micrométrique (4) lamellaire ayant un facteur de forme allant de 3 à 100, le ratio volumique entre la première charge (3) et la deuxième charge (4) allant de 95/05 à 40/60.  1 - Composite material for electrical insulation (I) comprising a matrix (2) of epoxy of cycloaliphatic type or of dlglycldylether type, and from 15 to 45% by volume of charges relative to the total volume of composite material of electrical insulation (1 ), characterized in that said composite electrical insulation material (1) comprises a first micrometric inorganic filler (3) having a form factor less than 5 and a second micrometric inorganic filler (4) having a form factor ranging from 3 to 100, the volume ratio between the first charge (3) and the second charge (4) ranging from 95/05 to 40/60.
2 - Matériau composite d'isolation électrique (1) selon la revendication 1, dans lequel la deuxième charge Inorganique micrométrique (4) a un facteur de forme allant de 10 à 50.  2 - Composite material for electrical insulation (1) according to claim 1, in which the second micrometric inorganic filler (4) has a form factor ranging from 10 to 50.
3 - Matériau composite d'isolation électrique (1) selon la revendication 1 ou 2, dans lequel la deuxième charge Inorganique micrométrique (4) est choisie parmi BN et AI2O3, et de préférence parmi hBN et Al2O3. 3 - Composite material for electrical insulation (1) according to claim 1 or 2, wherein the second micrometric inorganic charge (4) is chosen from BN and AI 2 O 3 , and preferably from hBN and Al 2 O 3 .
4 - Matériau composite d'isolation électrique (1) selon l'une quelconque dej revendications précédentes, dans lequel la première charge inorganique micrométrique (3) est choisie parmi SIO2, AI2O3, AI(OH)3, CaO, MgO, CaCOa, et TI02. 4 - Composite material for electrical insulation (1) according to any one of the preceding claims, in which the first micrometric inorganic charge (3) is chosen from SIO 2 , AI 2 O 3 , AI (OH) 3 , CaO, MgO , CaCOa, and TI0 2 .
5 - Matériau composite d'isolation électrique (1) selon l'une quelconque des revendications précédentes, dans lequel la teneur en charges va de 20 a 40% en volume, et de préférence de 25 à 35% en volume, par rapport au volume total du matériau composite d'isolation électrique (1).  5 - Composite material for electrical insulation (1) according to any one of the preceding claims, in which the charge content ranges from 20 to 40% by volume, and preferably from 25 to 35% by volume, relative to the volume. total of the electrical insulation composite material (1).
6 - Matériau composite d'isolation électrique (1) selon l'une quelconque des revendications précédentes, dans lequel le ratio volumique entre la première charge inorganique micrométrique (3) et la deuxième charge Inorganique micrométrique (4) va de 70/30 à 50/50.  6 - composite electrical insulation material (1) according to any one of the preceding claims, in which the volume ratio between the first micrometric inorganic charge (3) and the second micrometric inorganic charge (4) ranges from 70/30 to 50 / 50.
7 - Matériau composite d'isolation électrique (1) reion l'une quelconque des revendications précédentes, dans lequel la matrice (2) est une matrice époxy de type diglycidyléther, et de préférence une matrice époxy de type diglytidyléther de bbphénol A. 7 - composite material of electrical insulation (1) reion any one of the preceding claims, wherein the matrix (2) is a matrix diglycidyl ether type epoxy, and preferably a diglytidyl ether type epoxy matrix of bbphenol A.
8 - Matériau composite dlsolation électrique (1) selon Tune quelconque des revendications précédentes comprenant en outre une troisième charge micrométrique, distincte de la première charge inorganique micromëtrique (3) et de la deuxième charge inorganique micrométrique (4).  8 - electrical insulation composite material (1) according to any one of the preceding claims further comprising a third micrometric charge, distinct from the first micrometric inorganic charge (3) and from the second micrometric inorganic charge (4).
9 - Matériau composite dlsolation électrique (1) selon l'une quelconque des revendications précédentes, dans lequel la première charge inorganique micrométrique (3) et/ou la deuxième charge inorganique micrométrique (4) et/ou, lorsqu'elle est présente, la troisième charge micrométrique sont fonctionnalisées en surface.  9 - electrical insulation composite material (1) according to any one of the preceding claims, in which the first micrometric inorganic charge (3) and / or the second micrometric inorganic charge (4) and / or, when present, the third micrometric charge are functionalized on the surface.
10 - Matériau composite dlsolation électrique (1) selon l'une quelconque des revendications précédentes se présentant sous la forme d'un support Isolant électriquement (9) apte à maintenir en position un conducteur électrique (8) dans un poste sous enveloppe métallique (5).  10 - electrical insulation composite material (1) according to any one of the preceding claims, which is in the form of an electrically insulating support (9) capable of holding in position an electrical conductor (8) in a post in a metal envelope ).
11 - Procédé de fabrication d'un matériau composite d'isolation électrique (1) selon l'une quelconque des revendications précédentes comprenant les étapes suivantes :  11 - A method of manufacturing a composite electrical insulation material (1) according to any one of the preceding claims comprising the following steps:
a. préparation d'un mélange réticulable composé d'une résine époxy de type cycloaliphatique ou une de type di g lycidy lether d'une première charge inorganique micrométrique (3) ayant un facteur de forme inférieur à 3, d'une deuxième charge inorganique micrométrique (4) lamellaire ayant un facteur de forme allant de 3 à 100, et d'un agent de réticulation, b. introduction dudit mélange réticulable dans un moule, et c. réticulation du mélange réticulable situé dans le moule. at. preparation of a crosslinkable mixture composed of an epoxy resin of the cycloaliphatic type or one of the di g lycidy lether type of a first micrometric inorganic filler (3) having a form factor less than 3, of a second micrometric inorganic filler ( 4) lamellar having a form factor ranging from 3 to 100, and a crosslinking agent, b. introducing said crosslinkable mixture into a mold, and c. crosslinking of the crosslinkable mixture located in the mold.
12 - Procédé selon la revendication 11 dans lequel le mélange réticulable a une viscosité allant de 6000 mPa.s à 15000 mPa s, de préférence de 10000 mPa.s à 12000 mPas, mesurée à 80 °C selon la norme ISO 12058. 13 - Procédé selon la revendication 11 ou 12 dans lequel l'agent de réticulation est un activateur, ou un Initiateur, ou un durcisseur en combinaison avec un activateur ou avec un Initiateur, ou bien une combinaison d'un activateur, d'un initiateur et d'un durcisseur, 12 - Process according to claim 11 wherein the crosslinkable mixture has a viscosity ranging from 6000 mPa.s to 15000 mPa s, preferably from 10000 mPa.s to 12000 mPas, measured at 80 ° C according to ISO 12058 standard. 13 - The method of claim 11 or 12 wherein the crosslinking agent is an activator, or an initiator, or a hardener in combination with an activator or with an initiator, or a combination of an activator, an initiator and a hardener,
14 - Procédé selon l'une quelconque des revendications 11 à 13, dans lequel I Introduction du mélange néticulable dans le moule est réalisée par coulée gravitationnelle ou par injection.  14 - Process according to any one of claims 11 to 13, in which I Introduction of the mixable mixture into the mold is carried out by gravitational casting or by injection.
15 - Procédé selon l'une quelconque des revendications 11 à 14, dans lequel la réticulation est réalisée par application d'un moyen de réticulation tel que du chauffage ou des UV.  15 - Method according to any one of claims 11 to 14, wherein the crosslinking is carried out by application of a crosslinking means such as heating or UV.
16 - Procédé selon l'une quelconque des revendications 11 a 15 dans lequel le mélange réticuiable comprend en outre une troisième charge micrométrique.  16 - Method according to any one of claims 11 to 15 wherein the crosslinkable mixture further comprises a third micrometric load.
17 - Poste sous enveloppe métallique (b) comportant une enveloppe externe (6) délimitant Intérieurement une enceinte (7) dans laquelle est monté un conducteur électrique haute tension (8) à l'aide de supports Isolants électriques (9), caractérisé en ce que lesdits suppports isolants électriques (9) sont en un matériau composite d'isolation électrique (1) selon la revendication 10.  17 - Station in metal envelope (b) comprising an external envelope (6) internally delimiting an enclosure (7) in which a high voltage electrical conductor (8) is mounted using electric insulating supports (9), characterized in that that said electrically insulating supports (9) are made of a composite electrically insulating material (1) according to claim 10.
EP19762187.3A 2018-07-20 2019-07-17 Electrical insulation material comprising a mixture of micrometric inorganic fillers and manufacturing process Withdrawn EP3824480A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR1856761A FR3084202B1 (en) 2018-07-20 2018-07-20 ELECTRICAL INSULATION MATERIAL INCLUDING A MIXTURE OF INORGANIC MICROMETRIC CHARGES AND METHOD OF MANUFACTURING
PCT/FR2019/051795 WO2020016525A1 (en) 2018-07-20 2019-07-17 Electrical insulation material comprising a mixture of micrometric inorganic fillers and manufacturing process

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EP3824480A1 true EP3824480A1 (en) 2021-05-26

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JP (1) JP2021530082A (en)
KR (1) KR20210064183A (en)
CN (1) CN112424880A (en)
FR (1) FR3084202B1 (en)
WO (1) WO2020016525A1 (en)

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CN101035876A (en) * 2004-08-23 2007-09-12 莫门蒂夫性能材料股份有限公司 Thermally conductive composition and method for preparing the same
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JP4495768B2 (en) * 2008-08-18 2010-07-07 積水化学工業株式会社 Insulating sheet and laminated structure
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FR3084202A1 (en) 2020-01-24
JP2021530082A (en) 2021-11-04
CN112424880A (en) 2021-02-26
FR3084202B1 (en) 2020-10-23
WO2020016525A1 (en) 2020-01-23
KR20210064183A (en) 2021-06-02

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