Accelerating crosslinking of silane-grafted thermoplastics with water - by immersing in water and then insulating liquid to increase water permeation rate

摘要

Acceleration of moisture absorption of thermoplastics (I) e.g. olefin (co)polymers, which are rendered crosslinkable by moisture by grafting a silane (cpd.) onto the macromol, is effected by allowing water to diffuse into (I) by keeping in water and then flushing it into (I) by an insulating liquid (II) which is more soluble in (I) than water. Both diffusion and flushing pref. take place at 80-120 (ca.100) degrees C. (II) is a liquid stabiliser, pref. an aromatic oil, e.g. boron oil, alkylnaphthalenes, nitro-aromatics, opt. with OH and/or NH2 substits., organic liquid with OH gps., e.g. glycols or other diols, esp. polyether or polyester glycols, glycerol or aromatic alcohols. The water permeation rate is increased, so that even relatively thick walled crosslinked prods. can be made economically. The process is specified for use in the prodn. of electric leads and cables with crosslinked insulation and/or sheath.