摘要:
A cable includes at least one electrical conductor and at least one electrically insulating layer surrounding the electrical conductor, wherein the at least one electrically insulating layer includes: (a) a thermoplastic polymer material selected from: at least one copolymer (i) of propylene with at least one olefin comonomer selected from ethylene and an a-olefin other than propylene, the copolymer having a melting point greater than or equal to 130° C. and a melting enthalpy of 20 J/g to 90 J/g; a blend of at least one copolymer (i) with at least one copolymer (ii) of ethylene with at least one α-olefin, the copolymer (ii) having a melting enthalpy of 0 J/g to 70 J/g; a blend of at least one propylene homopolymer with at least one copolymer (i) or copolymer (ii); at least one of copolymer (i) and copolymer (ii) being a heterophasic copolymer; (b) at least one dielectric fluid intimately admixed with the thermoplastic polymer material; and (c) at least one water tree retardant selected from ethoxylated fatty acids and amide derivatives thereof.
摘要:
A cable for transporting or distributing electric energy, especially medium or high voltage electric energy, includes at least one electrical conductor, at least one electrically insulating layer surrounding the electrical conductor, and at least one sheath surrounding the electrically insulating layer, wherein the sheath includes 65% to 95% by weight of at least one thermoplastic ethylene polymer; 5% to 35% by weight of at least one plasticizing agent, the percentages being expressed with respect to the total weight of the sheath. The above sheath guarantees improved flexibility without impairing mechanical properties and particularly thermopressure resistance, which is essential to preserve shape and integrity of the screen layer during cable installation and use at high operating temperatures.
摘要:
A cable having at least one electrical conductor and at least one extruded covering layer based on a thermoplastic polymer material in admixture with a dielectric liquid. The thermoplastic polymer material is selected from: (a) at least one propylene homopolymer or at least one copolymer of propylene with at least one olefin comonomer; (b) a mechanical mixture of at least one propylene homopolymer or copolymer (a) and (c) at least one elastomeric copolymer or ethylene with at least one aliphatic α-olefin, and optionally a polyene. The cable of the invention possesses good mechanical and electrical properties, including high dielectric strength, in particular enabling it to be used at high operating temperature.
摘要:
A synthetic material is disclosed, which is constituted by a copolymer of D, L-lactide and &egr;-caprolactone (which itself is characterized by lower degradation times than those obtainable with copolymers of L-lactic acid and &egr;-caprolactone), obtained by using as reaction control agent a sugar dianhyide with non-toxic characteristics. The use of suar dianhydrde in the reaction has a considerable control effect on the molecular weight of the copolymer and, thanks to its low molecular weight, this copolymer is characterized by extreraely short resorption times, in the order for the example of one or two months. The copolymer is used as covering clement to be placed around tendon sutures and/or nerve tracts with the aim of preventing formation of scarry adherences between the suture lines and the soft surrounding tissues.
摘要:
Polymers and copolymers of L(+) and D(-) lactic acid, with high molecular weight and in the absence of catalysts, are prepared by upgrading low molecular weight polymers in the solid state.
摘要:
A cable includes at least one electrical conductor and at least one electrically insulating layer surrounding the electrical conductor, wherein the at least one electrically insulating layer includes: (a) a thermoplastic polymer material selected from: at least one copolymer (i) of propylene with at least one olefin comonomer selected from ethylene and an a-olefin other than propylene, the copolymer having a melting point greater than or equal to 130° C. and a melting enthalpy of 20 J/g to 90 J/g; a blend of at least one copolymer (i) with at least one copolymer (ii) of ethylene with at least one α-olefin, the copolymer (ii) having a melting enthalpy of 0 J/g to 70 J/g; a blend of at least one propylene homopolymer with at least one copolymer (i) or copolymer (ii); at least one of copolymer (i) and copolymer (ii) being a heterophasic copolymer; (b) at least one dielectric fluid intimately admixed with the thermoplastic polymer material; and (c) at least one water tree retardant selected from ethoxylated fatty acids and amide derivatives thereof.
摘要:
A cable having a conductor and a flame-retardant coating having (a) a polymer matrix; and (b) natural magnesium hydroxide particles having an average size (d50) of 0.5 μm to 5.0 μm and an average pore diameter less than or equal to 0.35 μm.
摘要:
Process for preparing an electrical cable comprising at least one conductor and at least one layer of extruded insulating coating, which includes: coating, by extrusion, the conductor with a polymeric composition comprising a polyethylene, a radical initiator and at least one unsaturated carboxylic acid of general formula (I) in free form: in which: R1 represents H or CH3; n represents 0 or 1; said unsaturated carboxylic acid being present in an amount of between 0.0006% and 0.25% by weight, said amount being expressed as the weight content of —COOH groups relative to the total weight of the polymeric composition; heating the conductor thus coated so as to obtain cross-linking of said polymeric composition.
摘要:
Preparation of fluorooxy-fluorosulfonyl-fluorocompounds by means of the direct fluorination with elemental fluorine of various .beta.-sultones according to the following reaction scheme: ##STR1## wherein R.sub.1 and R.sub.2, which can be either equal to, or different from, each other, represent a fluorine or chlorine atom, or an alkyl radical partially or totally halogenated with fluorine and/or chlorine.The reaction takes place in continuous in the presence of a fluorination catalyst, preferably constituted by an alkali-metal fluoride preferably supported on a metal material, at temperatures comprised within the range of from -30.degree. C. to +100.degree. C., and under the pressure comprised within the range of from 50 to 800 kPa; said catalyst is a fixed-bed catalyst, or is suspended in a reaction medium inert under the operating conditions.
摘要:
A cable includes at least one electrical conductor and at least one electrically insulating layer surrounding the electrical conductor, wherein the at least one electrically insulating layer includes: (a) a thermoplastic polymer material selected from: at least one copolymer (i) of propylene with at least one olefin comonomer selected from ethylene and an V-olefin other than propylene, the copolymer having a melting point greater than or equal to 130° C. and a melting enthalpy of from 20 J/g to 90 J/g; a blend of at least one copolymer (i) with at least one copolymer (ii) of ethylene with at least one V-olefin, the copolymer (ii) having a melting enthalpy of from 0 J/g to 70 J/g; a blend of at least one propylene homopolymer with at least one copolymer (i) or copolymer (ii); a blend of at least one propylene homopolymer with at least one copolymer (i) or copolymer (ii); (b) at least one nano-sized filler; wherein at least one of copolymer (i) and copolymer (ii) is a heterophasic copolymer.