Coloured silicone elastomers e.g. for wire insulation - by feeding uncoloured and coloured non-milling extended crosslinkable organo-siloxane! materials into extruder etc.

摘要

In a process for prodn. of coloured silicone rubber elastomer compsns., the processing unit used for final shaping and cross linking of the elastomer compsn., esp. an extruder, is fed simultaneously with (a) an unpigmented organopolysiloxane material in extended form, which can be heat cured to an elastomer and (b) a pigmented organopolysiloxane material in extended form which can be heat cured to an elastomer. Pref. compsn. (b) is used in an amt. of 1-40 wt.% w.r.t. compsn. (a), and the cross sectional area of the strip or other shape of the extended form the pigmented material (b) is 1/40 to 1/2 of the cross sectional area of the strip etc. (a). Process allows non-milling type heat curable silicone rubber compsns. to be processed by extrusion, injection moulding, transfer moulding, etc. into homogeneously coloured shaped articles, with considerable savings in storage space required for keeping coloured silicone elastomer compsns. in extended form.