Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B7/00—Insulated conductors or cables characterised by their form
  • H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
  • H01B7/29—Protection against damage caused by extremes of temperature or by flame
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
  • H01B13/22—Sheathing; Armouring; Screening; Applying other protective layers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B7/00—Insulated conductors or cables characterised by their form
  • H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
  • H01B7/29—Protection against damage caused by extremes of temperature or by flame
  • H01B7/292—Protection against damage caused by extremes of temperature or by flame using material resistant to heat
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B7/00—Insulated conductors or cables characterised by their form
  • H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
  • H01B7/29—Protection against damage caused by extremes of temperature or by flame
  • H01B7/295—Protection against damage caused by extremes of temperature or by flame using material resistant to flame
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
  • Y10T428/2933—Coated or with bond, impregnation or core

Definitions

• the present invention relates to a data transmission cable and / or fireproof coated energy and a method of flame retarding a coating of a data transmission cable and / or energy.
• a first conventional method consists in applying flame retardant (intumescent) paints to the cable after its installation.
• the treatment remains superficial, the depth of penetration being low, it does not allow fireproofing to the core of the coating.
• the charged compositions have a high viscosity and are often difficult to implement and the organic solvents used are expensive and polluting.
• a second conventional method is to incorporate in the insulation material fire retardants, halogenated or non-halogenated during the manufacture of the cable, most often at the moment when the polymeric composition used to obtain the insulation material is still liquid.
• the aim of the invention is to provide a method of incorporating at least one fire retardant into a coating of a cable, which process leads to a better control of the distribution of the fire retardant agent (s) in the coating. and preferably inexpensive, optimized in terms of yield and without impact on the environment.
• the invention proposes for this purpose a method of incorporating at least one fire retardant into a coating of a data transmission cable and / or energy characterized in that said incorporation is subsequent to the manufacture of said coating and is performed by means of a supercritical fluid.
• Supercritical fluid technology can impart or improve the fire resistance properties of any cable coating after its manufacture, in a sheath and / or insulating material, and prior to the installation of the cable.
• the supercritical fluid may be carbon dioxide CO 2 .
• said fire-retardant agent may be chosen from at least one of the following non-halogenated compounds: metal hydroxides, metal hydroxycarbonates, silica, philosilicates, zinc hydroxystannates and zinc stannates , phosphorus derivatives and boron compounds.
• metal hydroxides examples include magnesium hydroxide, aluminum trihydrate, hydromagnesite, hydroxide calcium and magnesium citrate.
• the metal hydroxides are natural or synthetic surface-treated or untreated with different particle sizes.
• metal hydroxycarbonates mention may be made of calcium carbonate and magnesium carbonate.
• the phosphorus derivatives improve the fire resistance of the materials by forming a protective charcoal layer.
• boron compounds such as metal borates (zinc borate, calcium borate for example) are effective fire retardants.
• the boron compounds can have a synergistic effect if they are used in combination with metal hydroxides. Indeed, the inorganic compounds such as metal hydroxides decompose endothermically, releasing water molecules which has the effect of lowering the temperature of the material and thus to delay its rate of degradation.
• said fire retardant may be selected from at least one of the following halogenated compounds: chlorine-based halogen compounds and bromine halogen compounds
• an incorporation temperature of less than 160 ° C. is chosen.
• the incorporation temperature is chosen very low to adapt to low thermal hydrates such as citrates which decompose at temperatures of 160 ° C.
• the fireproofing process may include the following operations: maintaining the fluid in the supercritical state for a predetermined duration to obtain incorporation into the coating,
• the object of the invention is also the development of a cable having a coating both flame-retardant and having good mechanical properties, cable preferably inexpensive, easy and quick to manufacture.
• the invention proposes for this purpose a data transmission cable and / or energy comprising a fireproof coating of a material incorporating at least one fire retardant agent characterized in that said coating has a concentration gradient so that the concentration in said at least one fire retardant on the outer surface of said coating is greater than the concentration of said at least one fire retardant on the inner surface of said coating.
• the term "outer surface” is defined as the surface of the coating furthest from the axis of said cable.
• the terms “inner surface” correspond to the surface of the coating closest to the axis of said cable.
• the coating according to the invention has its fire resistance properties due to a concentration of fire retardant agent at the surface and the mechanical properties enhanced by the decrease in the volume concentration.
• said fire-retardant agent may be chosen from at least one of the following non-halogenated compounds: metal hydroxides, metal hydroxycarbonates, silica, philosilicates, zinc hydroxystannates and zinc stannates , phosphorus derivatives and boron compounds.
• FIG. 1 schematically represents a cross-sectional view of a power transmission cable according to the invention in a preferred embodiment of the invention
• FIGS. 2 and 3 show diagrammatically the device for implementing the method according to the invention relating to the flameproofing of a coating of a transmission cable of energy or data by incorporation of at least one retarding agent fire in the coating.
• FIG. 1 shows a cross-section of a power transmission cable 1 which comprises, for example, a transmission element 2 such as an electrical conductor, made of copper, for example, coated with a sheath 3 itself coated with a coating 4 made of an insulating material, for example a polyethylene-type polymer incorporating fire-retardants 5, preferably a mixture of a boron compound with a metal citrate.
• a transmission element 2 such as an electrical conductor, made of copper, for example, coated with a sheath 3 itself coated with a coating 4 made of an insulating material, for example a polyethylene-type polymer incorporating fire-retardants 5, preferably a mixture of a boron compound with a metal citrate.
• Said coating 4 comprises an inner surface 42 in contact with said sheath 3 and an outer surface 41, said outer surface 41 being further from the axis of the electrical conductor 2 than said inner surface 42.
• the concentration of fire-retardant agents is greater than the periphery, or outer surface 41, of the coating 4 with respect to the inner surface 42 of the coating 4.
• said concentration at the surface external of said coating is 40% by weight of filler content relative to the total composition of said coating, or 0.80 g of fire retardant per cm 3 of coating at the periphery, while this concentration gradually decreases for attaining, at the core of said coating, 10% by weight of filler content with respect to the total composition of said coating, ie 0.20 g of fire retardant per cm 3 of coating in the core, and reaching, on the surface internal of said coating, a concentration of 0% by mass of filler rate with respect to the total composition of said coating
• the invention applies to both energy transmission cables and telecommunications cables, as data cables, electrical or optical fibers.
• the method according to the invention relates to the fireproofing of a coating of an energy or data cable by incorporating at least one fire retardant into the coating by means of a supercritical fluid.
• the coating material is an insulating and / or sheath material.
• the supercritical fluid preferably CO 2
• the supercritical state accumulates the molecular density of a liquid and the molecular mobility of a gas, two essential parameters in the reaction mechanisms at the interfaces.
• the surface tension of a supercritical fluid being negligible, it can all the more easily penetrate a polymeric material.
• the technique of the supercritical fluid makes it possible to achieve the optimization of the flame retardant properties referred to in the invention by means of a concentration gradient of fire retardant agent (s).
• the temperature and pressure conditions of the fluid in the supercritical state depend on the critical point of the fluid and the nature of the coating material and the choice of fire retardant (s) to be incorporated.
• the solvent power of a supercritical fluid depends mainly on its physical state described by its pressure, temperature and density, and its chemical nature, including its polarizability. As the density of the supercritical fluid increases, the intermolecular average distances decrease, which favors the specific interactions between the solvent and the fire retardant agent (s).
• the duration of the treatment depends on the supercritical fluid temperature and pressure conditions, the nature of the coating material and the choice of fire retardant (s) to be incorporated, the amount and desired gradient in the depth . At constant temperature, the density of the supercritical fluid increases with the pressure. For a given pressure, the increase in temperature will result in an increase in the vapor pressure of the fire retardant, and therefore in its volatility.
• FIGS. 2 and 3 show schematically the device for implementing the method according to the invention relating to the flameproofing of a coating of an energy or data cable by incorporating at least one fire retardant into the coating by means of a supercritical fluid.
• the device comprises a CO 2 source 10 connected to a pump 1 1 itself connected to a tubular reactor 6 such as an autoclave at adjustable temperature and pressure.
• Valves 12 make it possible to isolate the source 10 of the pump 11 and the reactor 6.
• the reactor 6 comprises a tubular body 61, a bottom 62, and a lid 63 provided with CO 2 introduction means (not shown) and connected to the pump 11.
• the cover 63 is arranged for the passage of a temperature probe 7, a pressure probe 8, and a drive system 90 of a stirrer 91 placed nearby. from the bottom 62.
• an energy or data cable provided with the external flame retardant coating 4, and at least one fire retardant agent intended to be incorporated in the coating is disposed in the bottom 62.
• the fire-retardant agent 5 is preferably chosen from the following non-halogenated compounds: metal hydroxides, metal hydroxycarbonates, silica, philosilicates, zinc hydroxystannates and zinc stannates, phosphorus derivatives and boron compounds.
• the reactor contains two fire-retardant agents, the first agent being a boron compound and the second agent being one of the following inorganic compounds: metal hydrates, metal hydroxides and preferably metallic citrates.
• the CO 2 is introduced into the reactor from the source 10.
• CO 2 proves to be a supercritical fluid particularly interesting because of its critical parameters (critical temperature equal to 31 ° C and critical pressure equal to 73 bar).
• Supercritical CO 2 has modulatable solvation properties of chemical species. It is the least expensive organic solvent among those commercially available, non-toxic, environmentally friendly and inert with respect to polymeric materials.
• the CO 2 is further purifiable by simple decompression of the reactor.
• the CO 2 is brought and maintained under the supercritical conditions chosen, preferably at a temperature below 165 ° C. and equal to Example at about 100 ° C for a pressure for example chosen equal to about 7.38 MPa and has a density of 0.132 g / cm 3 .
• the viscosity of the CO 2 is of the order of 10.sup.- 7 Pa.s.
• the mass transfer is favored by a low viscosity.
• the three samples each comprise a copper conductor with a diameter of one millimeter, covered with a 500 micron thick polyethylene insulation sheath and a coating one millimeter thick.
• the polymer constituting the insulating sheath is common to the three samples. This is a polyethylene.
• composition of the coating is different for the three samples: - the coating of sample 1 is composed of 100% by weight of ethylene-vinyl acetate copolymer (EVA) and does not contain a fire retardant agent
• EVA ethylene-vinyl acetate copolymer
• the coating of sample 2 is a homogeneous mixture composed of 50% by weight (relative to the total composition) of ethylene-vinyl acetate copolymer (EVA) and 50% by weight (relative to the total composition) of magnesium hydroxide.
• the coating material is prepared by mixing 500g of ethylene-acetate copolymer vinyl (EVA) containing 28% by weight of vinyl acetate, product sold under the trademark Evatane 28-03 by Arkema, with 500g of magnesium hydroxide Magnifin H10, sold by Albemarle.
• the mixture is produced in a mixer to be cycled at a temperature of 160 ° C., a rotation speed of 30 rpm and a duration of 20 minutes.
• the coating of the sample 3 is initially composed of 100% of ethylene-vinyl acetate copolymer (EVA).
• EVA ethylene-vinyl acetate copolymer
• Sample 3 is then placed in an autoclave in the presence of 500 g of Magnifin H10 magnesium hydroxide, sold by Albemarle for undergoing supercritical CO 2 treatment. This operation is carried out according to the procedure described above.
• the CO 2 is fed and maintained in the autoclave under supercritical conditions at a temperature of 100 ° C for a pressure of 7.38 MPa for about two hours.
• the CO 2 is removed from the reactor by reducing the pressure and temperature to the ambient pressure and temperature and allowing the CO 2 to escape under these conditions.
• the coating of sample 3 consists of a non-homogeneous mixture composed of ethylene-vinyl acetate copolymer (EVA) and magnesium hydroxide, the rate of fire retardant (magnesium hydroxide) being more important on the outer surface of the coating.
• EVA ethylene-vinyl acetate copolymer
• magnesium hydroxide magnesium hydroxide
• Table 1 summarizes the fire performance obtained with the three samples. Each test lasting up to 10 minutes allows the evaluation of the propagation time, which must be as long as possible. Table 1
• sample 2 is more efficient than sample 1 of reference.
• the propagation time is extended by 205 seconds. This result is not surprising because the coating of the sample
• Sample 3 can be compared to Sample 2 because both of them have the same flame retardant coating. It is observed that the propagation time of the sample 3 is increased by 150 seconds compared to the sample 2.
• the use of a supercritical CO 2 treatment therefore leads to a concentration of fire retardant agent greater than the surface. external coating and allows a strong improvement in propagation time.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Insulated Conductors (AREA)
• Organic Insulating Materials (AREA)
• Manufacturing Of Electric Cables (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (8)

Family Cites Families (22)

• 2005
  • 2005-10-03 FR FR0552994A patent/FR2891656B1/fr not_active Expired - Fee Related
• 2006
  • 2006-09-29 EP EP06831253A patent/EP1934991A1/de not_active Ceased
  • 2006-09-29 CA CA002625129A patent/CA2625129A1/fr not_active Abandoned
  • 2006-09-29 CN CN2006800392482A patent/CN101292304B/zh not_active Expired - Fee Related
  • 2006-09-29 JP JP2008532845A patent/JP2009510682A/ja active Pending
  • 2006-09-29 KR KR1020087010878A patent/KR20080059286A/ko not_active Application Discontinuation
  • 2006-09-29 WO PCT/FR2006/050967 patent/WO2007042699A1/fr active Application Filing
  • 2006-09-29 US US11/992,807 patent/US20110045294A1/en not_active Abandoned

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