Low smoke zero halogen flame retardant cable material processing and matters nee
Wire and cable materials to achieve the requirements of the low smoke zero halogen flame retardant, must add a large amount of inorganic flame retardants, extrusion, melt viscosity, flow performance is poor, easy to produce friction heat production, resulting in the melt temperature is too high, long residence time is easy to decompose the fuselage materials, decomposition of gas formation porosity in products easily. Low smoke zero halogen flame retardant wire and cable compound extrusion processing, attention should be paid to the following points.
(1) the choice of the extruder. Because of the low smoke zero halogen flame retardant wire and cable material additives is more, the melt viscosity, the screw with low compression should be used. Ordinary low shear rate of the single screw extruder, twin screw extruder with mixing capacity difference high mixing ability, but the processing of high fill low smoke zero halogen flame retardant wire and cable materials, materials decomposition, often because of excessive shear change, so it's best combination of single-screw and twin-screw mixing extruder double order. According to introducing reciprocating single screw mixer is the ideal low smoke zero halogen flame retardant wire and cable material processing equipment.
(2) the choice of processing technology. In addition to choose a suitable conversion, processing technology should also be reasonable. Such as high temperature can make the additive decomposition, resulting in products have air temperature is too low, will cause plasticizing adverse. Should try to reduce the pressure of the fuselage, the screw rotation speed is unfavorable and exorbitant under the condition of guarantee the sufficient plasticization, decreasing the right temperature. Machining process according to different materials, different formula to adjust.
(3) material extrusion processing before, must carry on the dry processing, lest produce pores in the products section.
(4) due to poor liquidity of materials, and equipment of frictional resistance is big, can improve the dispersion of inorganic flame retardant join organic silicon, reduce processing torque. The addition of organic silicon can improve the flame retardant performance of the electric wire electric cable, it is a kind of good processing AIDS.
In short, low smoke zero halogen flame retardant wire and cable material for processing equipment and strict process conditions and so on various aspects requirements, must according to the raw materials, products performance and extrusion characteristics to choose the appropriate extrusion equipment and process conditions.