A PROCESS FOR EXTRUSION

• Main Authors: PAUL JOSEPH CARONIA, SALVATORE FRANS SHUROTT
• Format: Patent
• Language: English; Spanish
• Published: 31.07.1997
• Edition: 6
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; BASIC ELECTRIC ELEMENTS; CABLES; CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; CONDUCTORS; ELECTRICITY; INSULATORS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING ORDIELECTRIC PROPERTIES; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

A process for the co-extrusion of an inner layer around a conductive medium and an outer layer around the inner layer comprising: (i( introducing into an extruder adapted for profile co-extrusion, a conductive medium; an inner layer formulation comprising a homogeneous polyethylene having a polydispersity in the range of about 1.5 to about 3.5 and an essentially uniform comonomer distribution and an organic peroxide; and an outer layer formulation comprising (a) a copolymer of ethylene and an unsaturated ester; (b) a polyethylene having a polydispersity greater than about 4.0 and a density of at least 0.916 gram per cubic centimeter, said polymer made by a high pressure process; or (c) a heterogeneous copolymer of ethylene and one or more alpha-olefins having a density of less than 0.916 gram per cubic centimeter, a melt index of at least about 4 grams per 10 minutes, and a polydispersity greater than about 4.0, and optionally, an organic peroxide; and (ii) co-extruding said formulations at a temperature not higher than about 160 degree C. Un proceso para la co-extrusion de una capa interna alrededor de un medio conductor y una capa externa alrededor de la capa interna que comprende: (i) introducir en un aparato de extrusion adaptado para co-extrusion de perfil, un medio conductor; una formulacion de capa interna que comprende un polietileno homogéneo que tiene una polidispersabilidad dentro de la escala de aproximadamente 1.5 a aproximadamente 3.5 y una distribucion de comonomero esencialmente uniforme, y un peroxido orgánico, y una formulacion de capa externa que comprende (a) un copolímero de etileno y un éster insaturado (b) un polietileno que tiene una polidispersidad mayor de aproximadamente 4.0 y una densidad de por lo menos 0.916 gramo por centímetro cubico, el polímero se elabora mediante un proceso de alta presion; o (c) un copolímero heterogéneo de etileno y una o más alfa-olefinas que tiene una densidad de menos de 0.916 gramo por centímetro cubico, un índice de fusion de por lo menos aproximadamente 4 gramos por 10 minutos, y una polidispersidad mayor de aproximadamente 4.0, y, opcionalmente, un peroxido orgánico; y (ii) co-extruir las formulaciones a una temperatura no mayor de aproximadamente 160 grados C.