| 摘要 |
<p>EP---3701 A Crosslinked cable insulation is applied by extrusion plasticisation and filtering of the matrix material before adding a chemical curing agent and releasing the extrudate through the coating die (17). The appts is also claimed. - The process is esp. for applying polyethylene insulation cured by mixture with an organic peroxide such as dicumyl peroxide, pref. dispersed in a paraffin oil or other liquid carrier. - Addition of the curing agent after filtration allows the polymer to be plasticised in an extruder (13) at temps. above the threshold temp. of the curing agent (14), to obtain high fluidity, and to be passed through a fine mesh screen pack, to reduce small particles of e.g. metallic contamination which would ruin the electrical insulation properties, without risk of premature curing of any resin delayed in dead zones in the vicinity of the screen pack. High cure zone temps. can be used adjacent to the outlet die (e.g. 150-160 degrees C for a system involving dicumyl peroxide), allowing lengths of post extrusion curing ovens to be reduced in length by at least half.</p> |
