WO2000079543A1 - Cable, in particular for electric energy transportation or distribution, and an insulating composition used therein - Google Patents
Cable, in particular for electric energy transportation or distribution, and an insulating composition used therein Download PDFInfo
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- WO2000079543A1 WO2000079543A1 PCT/EP2000/005446 EP0005446W WO0079543A1 WO 2000079543 A1 WO2000079543 A1 WO 2000079543A1 EP 0005446 W EP0005446 W EP 0005446W WO 0079543 A1 WO0079543 A1 WO 0079543A1
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- cable
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- terpolymer
- olefin
- ethylene
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- 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
- H01B3/44—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 vinyl resins; acrylic resins
- H01B3/441—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 vinyl resins; acrylic resins from alkenes
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/16—Elastomeric ethene-propene or ethene-propene-diene copolymers, e.g. EPR and EPDM rubbers
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2203/00—Applications
- C08L2203/20—Applications use in electrical or conductive gadgets
- C08L2203/202—Applications use in electrical or conductive gadgets use in electrical wires or wirecoating
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2205/00—Polymer mixtures characterised by other features
- C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/04—Homopolymers or copolymers of ethene
- C08L23/06—Polyethene
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/04—Homopolymers or copolymers of ethene
- C08L23/08—Copolymers of ethene
- C08L23/0807—Copolymers of ethene with unsaturated hydrocarbons only containing more than three carbon atoms
- C08L23/0815—Copolymers of ethene with aliphatic 1-olefins
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- 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
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- 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
- Y10T428/294—Coated or with bond, impregnation or core including metal or compound thereof [excluding glass, ceramic and asbestos]
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- 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
- Y10T428/294—Coated or with bond, impregnation or core including metal or compound thereof [excluding glass, ceramic and asbestos]
- Y10T428/2942—Plural coatings
- Y10T428/2947—Synthetic resin or polymer in plural coatings, each of different type
-
- 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
- Y10T428/294—Coated or with bond, impregnation or core including metal or compound thereof [excluding glass, ceramic and asbestos]
- Y10T428/296—Rubber, cellulosic or silicic material in coating
Definitions
- This invention relates to a cable, in particular for electric energy transportation or distribution, and an insulating composition used therein.
- the invention describes an electric cable and an insulating composition substantially free of lead or its derivatives, enabling cables to be produced having considerable mechanical and electrical properties and, in particular, an improved water resistance.
- Cables have to be protected to limit damage deriving from moisture, abrasion, atmospheric chemicals etc., and have therefore to offer specific characteristics dictated and governed by international regulations.
- Cables for medium or high voltage electric energy transportation or distribution usually comprise a core formed from a conductor surrounded by one or more coverings of cross-linked polymer material, in particular polyethylene or ethylene copolymers suitably cross-linked after extrusion onto the conductor.
- cross-linked materials maintain a high level of flexibility and satisfactory mechanical properties even under heating in continuous use and/or under current overload conditions.
- reinforcing fillers of various types such as calcined kaolin talc and the like, are usually added to the base polymer material.
- lead compounds are also added to the insulating composition, of which those currently most used are oxides, preferably Pb2 ⁇ 3 and Pb3 ⁇ 4, phthalates, phosphites and mono- and di-stearates .
- US 4204024 describes a composition based on an ethylene-propylene elastomer (EPR, i.e. ethylene-propylene rubber) or, preferably, a non-conjugated ethylene-propylene- diene terpolymer (EPDM, i.e. ethylene propylene diene monomer) , with vinyl silane, zinc oxide, a cross-linking agent (peroxide) and a cross-linking inhibitor to prevent premature cross-linking of the composition, the facility being provided to replace Pb2 ⁇ 3 or Pb3 ⁇ 4 with 0.1-2 parts by weight of lead peroxide, calculated on the compound, to eliminate the reddish coloration typically resulting from the use of said oxides.
- EPR ethylene-propylene elastomer
- EPDM non-conjugated ethylene-propylene- diene terpolymer
- a cross-linking agent peroxide
- a cross-linking inhibitor to prevent premature cross-linking of the composition
- WO 96/37899 describes a composition based on ethylene elastomer copolymers (EPR or EPDM, preferably obtained with metallocene catalysis) as the insulating material for cables, in which the lead compounds do not exceed one part by weight, calculated as the element.
- the compositions also contain a mineral filler in a quantity of 40-120 phr, i.e. parts per hundred rubber (of which at least 50% is calcined clay), a filler surface treatment agent (for example a silane) and zinc oxide in a quantity of between 10 and 30 phr .
- US 5274013 describes substantially lead-free elastomer compositions comprising a chlorinated polyolefin, preferably chlorinated polyethylene with a chlorine content of 25-45% by weight, an epoxide, a filler, a plasticizer, a cross-linking agent and possibly an EPDM polymer.
- Patent application WO97/00523 describes polymer compositions including EPDM polymers, in which the diene is vinyl norbornene, which enable a uniform surface of reduced roughness to be obtained, at a higher extrusion rate than conventional elastomer compositions based on EPDM polymers in which the diene is selected from the group consisting of 5-ethylidene-2-norbornene (ENB) , 1, 4-hexadiene (HEX), 1,6- octadiene, 5-methyl-l, 4-hexadiene, 3, 7-dimethyl-l, 6- octadiene and the like.
- the compositions described therein enable a good cross-linking rate and a high level of cross-linking to be obtained, with relatively low dielectric losses.
- Patent application WO98/56012 describes polymer compositions for cable insulation in which the base polymer material is a mixture of an EPDM terpolymer, substantially equivalent to the EPDMs described in WO97/00523, with a minority component in the form of an ethylene/ ⁇ -olefin copolymer prepared by metallocene catalysis, able to further improve the physical properties of the resultant mixture over that described in WO97/00523.
- the elastomer compositions described in both WO97/00523 and in WO98/56012 contemplate the presence of lead compounds, in the usual quantities (5 phr) for that f ield .
- chlorinated polymers involve evident environmental problems both during cable production and when the cable, at the end of its life, has to be disposed of in some manner.
- chlorinated polymers develop HC1 on heating, with outstanding corrosion problems for the cable production plant, and environmental pollution.
- the present applicant has unexpectedly found that the aforesaid technical problem can be solved by using as the base material for the insulating covering an elastomer terpolymer of ethylene, an ⁇ -olefin and 5-vinyl-2-norbornene, without the addition of lead-containing products.
- the present applicant has found that the electrical properties of the insulating covering, with reference in particular to dielectric strength and dielectric losses, remain substantially unaltered with time even in the presence of moisture, if the base material used for the insulating covering is an elastomer terpolymer of the following composition: a) 50-90 moles percent of ethylene; b) 10-50 moles percent of an ⁇ -olefin; c) 0.16-5 moles percent of 5-vinyl-2-norbornene; the sum of the moles percent of a), b) , c) being 100, said terpolymer having a branching index of less than or equal to 0.5 and a molecular weight distribution index M w /M n of greater than or equal to 6.
- the invention therefore provides an electric cable (1) comprising at least one conductor (2) and at least one insulating layer (4), wherein said insulating layer comprises a substantially lead-free polymer composition comprising as base polymer material an elastomer terpolymer having the following composition: a) 50-90 moles percent of ethylene; b) 10-50 moles percent of an ⁇ -olefin; c) 0.16-5 moles percent of 5-vinyl-2-norbornene; the sum of the moles percent of a), b) , c) being 100, said terpolymer having a branching index of less than or equal to 0.5 and a molecular weight distribution index M w /M n of greater than or equal to 6.
- substantially lead-free is meant to indicate that lead-containing substances are not added to the compositions of the invention or to the cables which use them. This does not however exclude that in the constituent materials of the insulating layer traces of lead or its derivatives may be present in negligible quantities and in any event less than the limits required to prevent environmental pollution problems.
- the ⁇ -olefin can be selected for example from propylene, 1-butene, 1-pentene, 1, 4-methyl-l-pentene, 1- hexene, 1-octene, 1-decene, 1-dodecene and the like and the combinations thereof.
- Propylene is particularly preferred for implementing the invention.
- the terpolymer has a Mooney viscosity [ML (1+4) at 125°C] of between 10 and 80, preferably between 15 and 60.
- the aforesaid terpolymer has a branching index of less than or equal to
- the cable comprises a substantially lead-free polymer composition having a zinc oxide content of less than 10 phr, preferably between 3 and 8 phr.
- the invention provides a substantially lead-free polymer composition
- a substantially lead-free polymer composition comprising as base polymer material an elastomer terpolymer having the following composition: a) 50-90 moles percent of ethylene; b) 10-50 moles percent of an ⁇ -olefin; c) 0.16-5 moles percent of 5-vinyl-2-norbornene; the sum of the moles percent of a) , b) , c) being 100, said terpolymer having a branching index of less than or equal to 0.5 and a molecular weight distribution index M w /M n of
- the invention provides a polymer composition in which the terpolymer has a Mooney viscosity [ML (1+4) at 125°C] of 10-80, preferably between 15 and 60.
- the substantially lead-free polymer compositions of the invention preferably have a zinc oxide content of less than 10 phr, in particular between 3 and 8 phr.
- the cable of the invention comprising at least one conductor and at least one insulating layer also comprises at least one layer (3, 5) with semiconductive properties which includes a polymer composition as aforedefined in which a conductive filler is dispersed.
- the relative degree of branching is calculated using the so- called branching index. The method for determining this index is described for example in "Ethylene-Propylene Elastomers", by Gray Ver Strate, Encyclopaedia of Polymer Science and Engineering, 6, 2nd Edition (1986) .
- This method comprises measuring the following characteristics of the terpolymer in solution: the weight-average molecular weight ( M W LALLS) i measured by low angle laser light scattering; the weight-average molecular weight (M ⁇ DRI ) anc * the viscometer-average molecular weight (M v op ) , both determined by measuring the differential refractive index; and the intrinsic viscosity (IV) measured in decalin at 135°C.
- the average branching index (BI) is defined as:
- the branching index is 1 for a linear polymer, whereas for a branched polymer this index is less than 1 and decreases as the degree of branching increases.
- the molecular weight distribution index (MDI) defined as the ratio of the weight-average molecular weight (M w ) to the number-average molecular weight (M n ) can be determined according to conventional techniques by gel permeation chromatography (GPC) .
- the elastomer terpolymers used in the invention are generally prepared by copolymerizing the corresponding monomers as described in patent application WO97/00523, the description of which is incorporated herein as reference. Further details concerning the synthesis of said terpolymers are given for example in Japanese patent applications JP 860151758 and JP 870210169, the descriptions of which are incorporated herein as reference.
- the elastomer terpolymers used in the invention are preferably prepared from the corresponding monomers in the presence of vanadium Ziegler-Natta catalysts or single-site catalysts, in particular metallocene catalysts.
- Metallocene catalysts are known to be coordination complexes between a transition metal usually of Group IV, in particular titanium, zirconium or hafnium, and two possibly substituted cyclopentadienyl ligands used in combination with a co- catalyst, for example an alumoxane, preferably
- elastomer terpolymers suitable for implementing the invention are obtainable commercially, for example under the name Vistalon R of Exxon Chemical.
- the cable of the invention includes an elastomer mixture comprising the elastomer terpolymer EPDM as heretofore described, in mixture with one or more different polymers already known in the art as materials for insulating electric cables. These additional polymers can be present in a quantity generally not exceeding 30 phr, preferably between 1 and 15 phr, of the mixture.
- polyolefins are generally polyolefins (either homopolymers or copolymers of different olefins) , selected for example from: polyethylene (PE), in particular low density PE (LDPE) , linear low density PE (LLDPE) , very low density PE (VLDPE or ULDPE) ; polypropylene (PP); thermoplastic propylene/ethylene copolymers; elastomer ethylene/propylene (EPR) or ethylene/ propylene/diene (EPDM) copolymers, and the like, or the mixtures thereof.
- PE polyethylene
- LDPE low density PE
- LLDPE linear low density PE
- VLDPE or ULDPE very low density PE
- PP polypropylene
- thermoplastic propylene/ethylene copolymers elastomer ethylene/propylene (EPR) or ethylene/ propylene/diene (EPDM) copolymers, and the like, or the mixtures thereof.
- EPR ethylene/
- the elastomer EPDM terpolymers suitable for the invention can be used in mixture with an ethylene/ ⁇ - olefin or ethylene/ ⁇ -olefin/diene copolymer prepared by copolymerizing the corresponding monomers in the presence of a single-site catalyst, in particular a metallocene or constrained geometry catalyst.
- the quantity of this copolymer is generally between 5 and 20% by weight with
- This copolymer has generally an M w /M n ratio of less than or equal to 4, preferably between
- composition distribution index (CDI) of greater than or equal to 45%, and a density of between 0.86 and 0.92 g/cm ⁇ .
- the CDI defined as the weight percentage of those copolymer molecules having an ⁇ -olefin content within
- the layer of insulating covering of the cable of the invention is preferably cross-linked by adding to the polymer composition a radical initiator, such as an organic peroxide selected for example from dicumyl peroxide, tert- butyl dicumyl peroxide, 2 , 5-dimethyl-2, 5-di (tert- butylperoxy) -hexane, ⁇ - ⁇ ⁇ -bis (tert-butylperoxy) diisopropyl- benzene and the like or the mixtures thereof.
- a radical initiator such as an organic peroxide selected for example from dicumyl peroxide, tert- butyl dicumyl peroxide, 2 , 5-dimethyl-2, 5-di (tert- butylperoxy) -hexane, ⁇ - ⁇ ⁇ -bis (tert-butylperoxy) diisopropyl- benzene and the like or the mixtures thereof.
- cross-linking agents are Dicup (dicumyl peroxide) and Vulkup R [ ⁇ - ⁇ ⁇ -bis ( tert-butylperoxy) diisopropyl-benzene] , both of Hercules .
- Ethylene/ ⁇ -olefin copolymers prepared with single-site catalysis are commercially obtainable under the names Engage ⁇ of Du Pont-Dow Elastomers and Exact R of Exxon Chemical.
- /0 generally comprises a reinforcing filler in a quantity of between 20 and 100 phr, preferably between 30 and 70 phr.
- Reinforcing fillers usable in the invention comprise for example calcium carbonate, calcined kaolin, talc and the like, or the mixtures thereof.
- a coupling agent can be added to the mixture, selected from those known in the art, for example silane compounds.
- silane compounds suitable for the purpose are ⁇ -methacryloxy-propyltrimethoxy silane, ethyltriethoxy silane, methyltris- (2-methoxyethoxy) silane, dimethyl ethoxy silane, vinyltris- (2-methoxyethoxy) silane, vinyltrimethoxy silane, vinyltriethoxy silane, octyltriethoxy silane, isobutyl-triethoxy silane, isobutyl- trimethoxy silane, and the mixtures thereof.
- the coupling agent can be used as such, or grafted onto at least one of the polymer components of the mixture.
- the quantity of coupling agent to be added to the mixture depends mainly on the type of coupling agent used and on the quantity of mineral filler added, and is generally between 0.05 and 10%, preferably between 0.1 and 5%, by weight on the total weight of the base polymer mixture.
- Other conventional components can be added to the aforedefined base polymer material, for example antioxidants, processing aids, lubricants, pigments, water- tree retardants, voltage stabilizers and the like.
- antioxidants suitable for the purpose are for example: polymerized trimethyl-dihydroquinoline (for example poly-2, 2, 4-trimethyl-l, 2-dihydroquinoline) ; 4,4' -thiobis- (3- methyl-6-tert-butyl) -phenol; pentaerythryl-tetra- [3- (3, 5- ditert-butyl-4-hydroxyphenyl) propionate] ; 2,2'-
- processing aids usually added to the polymer base are for example calcium stearate, zinc stearate, stearic acid, paraffin wax, silicone rubbers and the like, or the mixtures thereof.
- the aforedefined polymer compositions can be advantageously used to form an insulating layer.
- these compositions enable high mechanical characteristics to be achieved both at room temperature and under heating, and also provide improved electrical properties, in particular such as to maintain dielectric strength substantially unaltered with time, even in the presence of moisture.
- a conductive filler particularly carbon black
- a conductive filler is preferably dispersed within the polymer material in a quantity such as to impart semiconductive properties to the material (i.e. such as to obtain a resistivity of less than 5 ohm.m at room temperature) .
- This quantity is generally between 5 and 80 % by weight, preferably between 10 and 50% by weight, on the total mixture weight .
- the ability to use the same type of polymer material both for the insulating layer and for the semiconductive layers is particularly advantageous in producing cables for medium or high voltage, in that it ensures optimum adhesion between adjacent layers and hence an improved electrical behaviour particularly at the interface between the insulating layer and the inner semiconductive layer where the electrical field and hence the risk of partial discharges are higher.
- "low voltage” generally means a voltage less than 1 kV
- intermediate voltage means a voltage between 1 and 35 kV
- high voltage means a voltage greater than 35 kV.
- the insulating composition of the invention can be prepared by mixing together the polymer component, the filler and any other additives present by methods known in the art. Mixing can be for example by an internal mixer of tangential (Banbury) or copenetrating rotor type, or by continuous mixers of Ko-Kneader (Buss) type or of co-rotating or counter-rotating double-screw type.
- Mixing can be for example by an internal mixer of tangential (Banbury) or copenetrating rotor type, or by continuous mixers of Ko-Kneader (Buss) type or of co-rotating or counter-rotating double-screw type.
- the cable of the invention can be formed by techniques conventionally used in the field, for example by extruding the polymer composition, cross-linking and cooling. Further details will be apparent from the following description, given with reference to the accompanying drawings, on which:
- Figure 1 is a perspective view of an electric cable particularly suitable for medium voltage, in accordance with the invention
- Figure 2 shows the variation of dielectric strength with time for three compositions formed from three different EPDM polymers .
- the cable 1 comprises a conductor 2, an inner layer with semiconductive properties 3, an intermediate layer with insulating properties 4, an outer layer with semiconductive properties 5, a metal screen 6, and an outer sheath 7.
- the conductor 2 generally consists of metal wires, preferably of copper or aluminium, stranded together by conventional methods.
- the insulating layer 4 and the possible semiconductive layers 5 and 6 comprise the aforedescribed polymer composition as their base polymer material.
- a screen 6 generally consisting cf electrically conducting wires or tapes, helically wound. This screen is then covered with a sheath 7 of a thermoplastic material, for example non crosslinked polyethylene (PE) .
- PE non crosslinked polyethylene
- Figure 1 shows only one possible embodiment of a cable according to the invention. It is evident that suitable modifications known in the art can be made to this embodiment, but without departing from the scope of the invention.
- the polymer compositions of the invention can also be advantageously used to cover cables for telecommunications or data transmission, or mixed energy/telecommunications cables.
- EPDM terpolymers A, B and C the characteristics of which are shown in ⁇ Table 1, were used to prepare the compositions A, B and C shown in Table 1.
- Silane A-172 (VTMOEO) of WITCO SPECIALITIES vinyltris- (2- methoxyethoxy) silane;
- Antioxidant ANOX R HB of GREAT LAKES poly-2, 2 , 4-trimethyl- 1, 2-dihydroquinoline;
- composition C The polymer compositions of the invention (composition C) were compared with other EPDM polymers (compositions A and B) , varying the catalysis and the diene, and encountering better water resistance.
- compositions were also prepared without adding lead.
- compositions A, B and C were prepared using a 1.6 litre
- Banbury mixer with a volumetric filling coefficient of about 75%.
- the compositions obtained were used to prepare 1 mm cross-linked plates by compression moulding at 190-195°C and
- Test-pieces were punched from these plates and were subjected to stress at break (SB) and elongation at break
- composition C The other electrical and mechanical properties of the polymer compositions of the invention (composition C) are at least comparable to those presented by the other comparison mixtures (compositions A and B) , as can be seen from the following table.
- ODR oscillating disc rheometer
- ML minimum torque
- M ⁇ j maximum torque
- t90 time at which a torque of M L + 0.90 (M H - M L ) is obtained;
- composition C The dielectric strength of the polymer compositions of the invention (composition C) was evaluated on test-pieces obtained by the ageing method proposed by EFI (Norwegian Electric Power Research Institute) in the publication "The EFI Test Method for Accelerated Growth of Water Trees, presented at the "1990 IEEE International Symposium on Electrical Insulation", held in Toronto, Canada, 3-6 June 1990, and compared with the already defined polymer compositions A and B.
- EFI Newegian Electric Power Research Institute
- the cable is simulated by forming multi-layer test-pieces of cup shape, in which the constituent material of the insulating covering is sandwiched between two layers of semiconductive material More specifically, starting from a strip of thickness 5-7
- the layer of insulating material is thermoformed to cup shape at a temperature of 120°C in an electrical press able to develop a pressure of about 90 t, to hence obtain a thickness of about 0.50 mm.
- Layers of semiconductive material, extruded and preformed in a similar manner until a thickness of about 0.5 mm is achieved, are then pressed and heat-bonded onto opposite sides of the insulating layer at a temperature of about 180°C for 15 minutes in an electrical press similar to that used for forming the layers themselves.
- test-pieces obtained in this manner are subjected to an accelerated electrical ageing test by filling the cavity defined inside the test-piece with water, immersing a high-voltage electrode in the water and resting them on a metal plate (earth electrode) .
- test-pieces were subjected to accelerated ageing in water under the following test conditions:
- the dielectric strength was then measured in accordance with standard ASTM D-149 on a batch of 5 non-aged test-pieces (reference) and a batch of 3 test-pieces withdrawn 30 days after commencement of the accelerated electrical ageing.
- the dielectric strength tests were carried out with silicone
- the loss factor was measured using as test- pieces moulded flat plates of 20 x 20 cm side and 1.0 mm thickness, and using circular electrodes with a guard ring. Before making the measurements, the test-pieces were heat- treated at 90°C for 100 hours to eliminate cross-linkage by- products from each plate.
- compositions A, B and C were used to produce medium-voltage cables.
- the cables were prepared by extrusion through a triple-head extruder onto a 1/0 AWG conductor consisting of an aluminium wire cord of about 54mm2 cross-section.
- the extruder of 100 mm internal diameter, had the following temperature profile: from 90 to 110°C within the cylinder, 120°C on the collar and 120°C within the head.
- the line speed was 2 m/min.
- the cables obtained in this manner had an inner semiconductive layer of 0.5 mm thickness, an insulating layer of 4.6 mm and an outer semiconductive layer of 0.5 mm.
- the histograms show the water resistance, evaluated by measuring the variation in dielectric strength, expressed in kV/mm, against time for the three cables formed from the polymer compositions A, B and C. At zero time it can be seen that the cables have substantially the same dielectric strength. After one month there is a slight increase in the values, followed after 3 months by a visible difference in behaviour of the cables formed from the three different compositions, however the results are still comparable.
- ZO composition C of the invention shows no substantial difference from the values found after 3 months.
- the water resistance of the insulating layer in the cables prepared in this manner was evaluated by a method by ENEL (Ente Nazionale Energia Elettrica, ENEL Standard DC4584, December 1991, Ed. I - 14/40), described below.
- ENEL Ente Nazionale Energia Elettrica, ENEL Standard DC4584, December 1991, Ed. I - 14/40
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- Organic Chemistry (AREA)
- Organic Insulating Materials (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
Description
Claims
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE60013831T DE60013831T2 (en) | 1999-06-21 | 2000-06-14 | CABLES, IN PARTICULAR FOR ELECTRIC ENERGY TRANSPORT OR FOR THE DISTRIBUTION OF ENERGY |
PT00943802T PT1192624E (en) | 1999-06-21 | 2000-06-14 | CABLE, IN PARTICULAR FOR TRANSPORT OR DISTRIBUTION OF ELECTRICAL ENERGY |
AT00943802T ATE276574T1 (en) | 1999-06-21 | 2000-06-14 | CABLES, ESPECIALLY FOR ELECTRICAL ENERGY TRANSPORT OR DISTRIBUTION |
AU58141/00A AU5814100A (en) | 1999-06-21 | 2000-06-14 | Cable, in particular for electric energy transportation or distribution, and an insulating composition used therein |
EP00943802A EP1192624B1 (en) | 1999-06-21 | 2000-06-14 | Cable, in particular for electric energy transportation or distribution |
US10/022,206 US6815062B2 (en) | 1999-06-21 | 2001-12-20 | Cable, in particular for electric energy transportation or distribution, and an insulating composition used therein |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP99111860.5 | 1999-06-21 | ||
EP99111860 | 1999-06-21 | ||
US14044899P | 1999-06-23 | 1999-06-23 | |
US60/140,448 | 1999-06-23 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/022,206 Continuation US6815062B2 (en) | 1999-06-21 | 2001-12-20 | Cable, in particular for electric energy transportation or distribution, and an insulating composition used therein |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2000079543A1 true WO2000079543A1 (en) | 2000-12-28 |
Family
ID=45570620
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/EP2000/005446 WO2000079543A1 (en) | 1999-06-21 | 2000-06-14 | Cable, in particular for electric energy transportation or distribution, and an insulating composition used therein |
Country Status (8)
Country | Link |
---|---|
EP (1) | EP1192624B1 (en) |
AR (1) | AR024408A1 (en) |
AT (1) | ATE276574T1 (en) |
AU (1) | AU5814100A (en) |
DE (1) | DE60013831T2 (en) |
ES (1) | ES2228558T3 (en) |
PT (1) | PT1192624E (en) |
WO (1) | WO2000079543A1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2002059909A1 (en) * | 2001-01-25 | 2002-08-01 | Nkt Cables A/S | An insulation system, in particular for electric power cables |
EP1453866A2 (en) * | 2001-04-23 | 2004-09-08 | ExxonMobil Chemical Patents Inc. | Blends of epdm and metallocene plastomers for wire and cable applications |
WO2006047013A1 (en) * | 2004-10-25 | 2006-05-04 | Exxonmobil Chemical Patents Inc. A Corporation Of State Of Delaware | Blends of ethylene-alpha-olefin-diene polymers and ethylene-alpha-olefin polymers for wire and cable applications |
WO2007117663A2 (en) * | 2006-04-06 | 2007-10-18 | Dow Global Technologies, Inc. | Expandable polyolefin compositions and insulated vehicle parts containing expanded polyolefin compositions |
WO2014029447A1 (en) * | 2012-08-24 | 2014-02-27 | Abb Research Ltd | A high voltage direct current cable product |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU2006306188B2 (en) | 2005-10-25 | 2011-08-25 | General Cable Technologies Corporation | Improved lead-free insulation compositions containing metallocene polymers |
EP2430641A4 (en) * | 2009-05-14 | 2014-06-18 | Gen Cable Technologies Corp | Improved insulation compositions containing zinc stabilizers |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5274013A (en) * | 1992-06-01 | 1993-12-28 | The Dow Chemical Company | Moisture resistant thermoset cable jacket |
WO1997000288A1 (en) * | 1995-06-14 | 1997-01-03 | Exxon Chemical Patents Inc. | Thermoplastic elastomers having improved cure |
WO1997000523A1 (en) * | 1995-06-14 | 1997-01-03 | Exxon Chemical Patents Inc. | ELECTRICAL DEVICES INCLUDING ETHYLENE, α-OLEFIN, VINYL NORBORNENE ELASTOMERIC POLYMERS |
JPH09157465A (en) * | 1995-12-05 | 1997-06-17 | Furukawa Electric Co Ltd:The | Rubber composition for electrical insulation |
WO1998056012A1 (en) * | 1997-06-05 | 1998-12-10 | Exxon Chemical Patents Inc. | Electrical devices including ethylene, alpha-olefin, vinyl norbornene elastomers and ethylene alpha-olefin polymers |
EP0893802A1 (en) * | 1997-07-23 | 1999-01-27 | PIRELLI CAVI E SISTEMI S.p.A. | Cables with a halogen-free recyclable coating comprising polypropylene and an ethylene copolymer having high structural uniformity |
-
2000
- 2000-06-14 PT PT00943802T patent/PT1192624E/en unknown
- 2000-06-14 AT AT00943802T patent/ATE276574T1/en active
- 2000-06-14 ES ES00943802T patent/ES2228558T3/en not_active Expired - Lifetime
- 2000-06-14 WO PCT/EP2000/005446 patent/WO2000079543A1/en active IP Right Grant
- 2000-06-14 EP EP00943802A patent/EP1192624B1/en not_active Expired - Lifetime
- 2000-06-14 DE DE60013831T patent/DE60013831T2/en not_active Expired - Lifetime
- 2000-06-14 AU AU58141/00A patent/AU5814100A/en not_active Abandoned
- 2000-06-20 AR ARP000103047A patent/AR024408A1/en not_active Application Discontinuation
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5274013A (en) * | 1992-06-01 | 1993-12-28 | The Dow Chemical Company | Moisture resistant thermoset cable jacket |
WO1997000288A1 (en) * | 1995-06-14 | 1997-01-03 | Exxon Chemical Patents Inc. | Thermoplastic elastomers having improved cure |
WO1997000523A1 (en) * | 1995-06-14 | 1997-01-03 | Exxon Chemical Patents Inc. | ELECTRICAL DEVICES INCLUDING ETHYLENE, α-OLEFIN, VINYL NORBORNENE ELASTOMERIC POLYMERS |
JPH09157465A (en) * | 1995-12-05 | 1997-06-17 | Furukawa Electric Co Ltd:The | Rubber composition for electrical insulation |
WO1998056012A1 (en) * | 1997-06-05 | 1998-12-10 | Exxon Chemical Patents Inc. | Electrical devices including ethylene, alpha-olefin, vinyl norbornene elastomers and ethylene alpha-olefin polymers |
EP0893802A1 (en) * | 1997-07-23 | 1999-01-27 | PIRELLI CAVI E SISTEMI S.p.A. | Cables with a halogen-free recyclable coating comprising polypropylene and an ethylene copolymer having high structural uniformity |
Non-Patent Citations (1)
Title |
---|
DATABASE WPI Section Ch Week 199734, Derwent World Patents Index; Class A12, AN 1997-369616, XP002123372 * |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2002059909A1 (en) * | 2001-01-25 | 2002-08-01 | Nkt Cables A/S | An insulation system, in particular for electric power cables |
EP1453866A2 (en) * | 2001-04-23 | 2004-09-08 | ExxonMobil Chemical Patents Inc. | Blends of epdm and metallocene plastomers for wire and cable applications |
EP1453866A4 (en) * | 2001-04-23 | 2004-09-22 | Exxonmobil Chem Patents Inc | Blends of epdm and metallocene plastomers for wire and cable applications |
US7750080B2 (en) | 2001-04-23 | 2010-07-06 | Exxonmobil Chemical Patents Inc. | Blends of EPDM and metallocene plastomers for wire and cable applications |
WO2006047013A1 (en) * | 2004-10-25 | 2006-05-04 | Exxonmobil Chemical Patents Inc. A Corporation Of State Of Delaware | Blends of ethylene-alpha-olefin-diene polymers and ethylene-alpha-olefin polymers for wire and cable applications |
WO2007117663A2 (en) * | 2006-04-06 | 2007-10-18 | Dow Global Technologies, Inc. | Expandable polyolefin compositions and insulated vehicle parts containing expanded polyolefin compositions |
WO2007117663A3 (en) * | 2006-04-06 | 2007-12-06 | Dow Global Technologies Inc | Expandable polyolefin compositions and insulated vehicle parts containing expanded polyolefin compositions |
WO2014029447A1 (en) * | 2012-08-24 | 2014-02-27 | Abb Research Ltd | A high voltage direct current cable product |
Also Published As
Publication number | Publication date |
---|---|
DE60013831D1 (en) | 2004-10-21 |
EP1192624A1 (en) | 2002-04-03 |
ATE276574T1 (en) | 2004-10-15 |
ES2228558T3 (en) | 2005-04-16 |
PT1192624E (en) | 2005-02-28 |
AU5814100A (en) | 2001-01-09 |
AR024408A1 (en) | 2002-10-02 |
EP1192624B1 (en) | 2004-09-15 |
DE60013831T2 (en) | 2005-10-06 |
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