Patent ID: 7182888

Claim:
A method for producing a conductive masterbatch comprising a polyamide and conductive carbon black, said conductive carbon black being present in the form of at least one agglomerated particle having a major axis of 20 to 100 μm, wherein the number of said at least one agglomerated particle is 1 to 100 as observed under an optical microscope with respect to a contiguous area of 3 mm 2 , said method comprising: (1) feeding a polyamide to a twin-screw extruder or kneader, followed by melting of said polyamide to obtain a molten polyamide, wherein said twin-screw extruder or kneader has at least one first inlet and at least one second inlet, said at least one first inlet being provided upstream of said at least one second inlet as viewed in an extrusion direction of said extruder or kneader, and wherein said polyamide is fed through said at least one first inlet of said extruder or kneader; and (2) adding conductive carbon black and optionally an additional amount of a polyamide simultaneously to the molten polyamide in said extruder or kneader through said at least one second inlet thereof, followed by melt-kneading of the resultant mixture to obtain a conductive masterbatch.