Abstract: TRXLPE-type cable sheaths are prepared by a method in which a solid polymer is mixed with a liquid water tree-resistant agent either by dosing or direct injection. In the dosing method, the solid polymer, e.g., high pressure LDPE, is sprayed or otherwise contacted with the liquid agent, e.g., PEG, the agent is allowed to absorb into the polymer, and the polymer with absorbed agent is then fed to an extrusion apparatus for extrusion over a sheathed or unsheathed wire or optic fiber. In the direct injection method, the solid polymer is first fed to an extrusion apparatus, and the liquid agent is sprayed or otherwise contacted with the polymer before the two are blended with one another through the action of the mixing elements of the apparatus.

Abstract: The present invention is an improved power cable construction. Through the use of a multi-ply insulation layer, the resulting power cable retains the water tree or electrical tree resistance of generally-used tree-retardant power cables even though a conventional polymer insulation composition substantially replaces the tree-retardant polymer composition. An improved process that takes advantages of the multi-ply system is also taught.

Abstract: TRXLPE-type cable sheaths are prepared by a method in which a solid polymer is mixed with a liquid water tree-resistant agent either by dosing or direct injection. In the dosing method, the solid polymer, e.g., high pressure LDPE, is sprayed or otherwise contacted with the liquid agent, e.g., PEG, the agent is allowed to absorb into the polymer, and the polymer with absorbed agent is then fed to an extrusion apparatus for extrusion over a sheathed or unsheathed wire or optic fiber. In the direct injection method, the solid polymer is first fed to an extrusion apparatus, and the liquid agent is sprayed or otherwise contacted with the polymer before the two are blended with one another through the action of the mixing elements of the apparatus.

Abstract: Cable insulation layers having excellent mechanical and electrical properties are prepared from a composite free of plasticizer and comprising a heterogeneous, polymeric composition comprising (A) a polypropylene matrix, and (B) a propylene copolymer dispersed within the matrix and (i) comprising more than 80 weight percent (wt %) of units derived from propylene, and (ii) having a weight average particle size of less of than 1 micron (?m). The insulation layer is not only environmental friendly due to the lack of placticizer, but it also maintains its physical and operational integrity at temperatures of at least 90° C.

Abstract: A high-voltage direct current cable insulation is made from a blend which includes an ethylene copolymer, such as ethylene-alpha olefin copolymer, with low crystallinity to reduce physical space charge trapping sites, a polar polymer modifier in an effective amount to enhance local conductivity to leak space charge quickly when local stress is enhanced, and an ion scavenger to stabilize or neutralize the space charge to provide a composition which is an effective high-voltage DC cable insulation. A high-voltage direct current cable semiconductive shield is made from a blend that includes an ethylene copolymer, a carbon black having a low level of ionic species, a polar polymer modifier, and an ion scavenger.

Abstract: This invention is directed to a cable for electrical conductors which has insulation layer which includes a 2,2,6,6-tetramethylpiperidine and a strippable insulation shield layer which includes a copolymer of acrylonitrile and butadiene.

Abstract: A high-voltage direct current cable insulation is made from a blend which includes an ethylene copolymer, such as ethylene-alpha olefin copolymer, with low crystallinity to reduce physical space charge trapping sites, a polar polymer modifier in an effective amount to enhance local conductivity to leak space charge quickly when local stress is enhanced, and an ion scavenger to stabilize or neutralize the space charge to provide a composition which is an effective high-voltage DC cable insulation. A high-voltage direct current cable semiconductive shield is made from a blend that includes an ethylene copolymer, a carbon black having a low level of ionic species, a polar polymer modifier, and an ion scavenger.

Abstract: A high voltage direct current cable insulation is made from a blend which includes an ethylene copolymer, such as ethylene-alpha olefin copolymer, with low crystallinity to reduce physical space charge trapping sites, a polar polymer modifier in an effective amount to enhance local conductivity to leak space charge quickly when local stress is enhanced, and an ion scavenger to stabilize or neutralize the space charge to provide a composition which is an effective high voltage DC cable insulation.

Abstract: A process for selecting and extruding a copolymer having improved extrusion processability comprising (a) selecting one or more copolymers of ethylene and one or more alpha-olefins having 3 to 12 carbon atoms, each of said copolymers having essentially no long chain branching and having (1) a melt index selected from the range of about 0.1 to about 20 grams per 10 minutes, and (2) a melt flow ratio having at least about a value determined by the following formula: 2.7183 to the power of {(1.477 minus [0.279 times the natural logarithm of the selected melt index]) divided by 0.29} and (b) extruding said copolymer around an electrical conductor.

Abstract: A cable comprising one or more electrical conductors or a core of one or more electrical conductors, each conductor or core being surrounded by a layer of insulation comprising a multimodal copolymer of ethylene and one or more alpha-olefins, each alpha-olefin having 3 to 8 carbon atoms, the copolymer having a broad comonomer distribution as measured by TREF with a value for the percent of copolymer, which elutes out at a temperature of greater than 90 degrees C., of greater than about 5 percent; a WTGR value of less than about 20 percent; a melt index in the range of about 0.1 to about 30 grams per 10 minutes; and a density in the range of 0.880 to 0.950 gram per cubic centimeter, and being prepared by a low pressure process.

Abstract: In the operation of a melter/mixer-gear pump system for processing of synthetic thermoplastic materials, the improvement is disclosed which comprises employing the pressure between the melter/mixer and the gear pump as the controlling parameter which affects, in a proportional relationship, the speed of the gear pump, the energy transmitted to and the consequent temperature of the materials passing through said melter/mixer.