Co-extruded electric conductor cable in three insulating layers of low humidity absorption electric method low smoke and toxic gas emission flame retardant

A process for preparing a co-extruded triple layer electric conductor cable having low humidity absorption insulation, low emission of toxic gases and smoke and a high flame resistance, comprising the steps of:

• a) providing a first layer around the conductor core having a low smoke emission, a low dielectric constant and a thermal class of 105.degree. C., said first layer comprising polyvinyl chloride compound as a base;
• b) depositing a second layer over said first layer, comprising a high density polyethylene compound having a flow index of from about 0.15 to about 1.0;
• said polyethylene modified with an ethylene polymer having a concentration of from about 0 to about 60% over said first layer;
• c) depositing a third layer over said second layer having a low emission and a low dielectric constant, comprising a polyvinyl chloride compound as a base;
• d) separately preparing the polymeric composition of each of the insulating layers of (a), (b) and (c);
• e) simultaneously extruding the said layers in an arrangement of similar size extruders;
• f) passing the layers through an extrusion head;
• said head overlapping the three insulating layers forming one sole concentric insulating layer around the conductor core;
• and
• g) preventing the individual layers from diffusing among them.

A process for insulating an electric conductor core comprising the steps of:

• a) providing a co-extruded triple layer electric conductor cable having a low humidity absorption insulation, a low emission of toxic gases and smoke and a high flame resistance, comprising:
• i) a first layer over the conductor core, having a low smoke emission, a low dielectric constant and a thermal class of 105.degree. C.;
• said first layer comprising polyvinyl chloride compound as a base;
• ii) a second layer over said first layer, as a humidity barrier comprising a high density polyethylene compound having a flow index of from about 0.15 to about 1.0;
• said polyethylene modified with an ethylene polymer having a concentration of from about 0 to about 60%;
• iii) a third layer over said second layer, having a low emission, a low dielectric constant, a high mechanical resistance and a high sliding grade;
• said third layer comprising polyvinyl chloride compound as a base;
• b) applying the triple insulating layers around the conductor core.

A co-extruded triple layer electric conductor cable having low humidity absorption insulation, low emission of toxic gases and smoke and a high flame resistance prepared by a process comprising the steps of:

• a) providing a first layer around the conductor core comprising polyvinyl chloride compound as a base;
• b) depositing a second layer over said first layer, comprising a high density polyethylene compound having a flow index of from about 0.15 to about 1.0;
• said polyethylene optionally modified with an ethylene polymer having a concentration of from about 0 to about 60% over said first layer;
• c) depositing a third layer over said second layer, comprising a polyvinyl chloride compound as a base;
• d) separately preparing the polymeric composition of each of the insulating layers of (a), (b) and (c);
• e) simultaneously co-extruding the said layers in an arrangement of similar size extruders;
• f) passing the layers through an extrusion head;
• said head overlapping the three insulating layers forming one sole concentric insulating layer around the conductor core, and
• g) preventing the individual layers from diffusing among them.