Calcium carbonate filled halogen-free flame-retardant PP material and preparation method thereof

The invention relates to a preparation method of a calcium carbonate filled halogen-free flame-retardant PP material, which comprises the following components in percentage by weight: 45 to 55 wt% of calcium carbonate, 27 to 33 wt% of PP particle, 12 to 17 wt% of halogen-free flame retardant, 1 to 2 wt% of antioxidant, and 4 to 7 wt% of organic silicon, wherein the total weight percentage is 100 wt%. The preparation method comprises the following steps: (1) mixing PP particles and calcium carbonate, and blending the PP particles and calcium carbonate at a temperature of 80 DEG C in a low speed automatic metering mixer in a low speed; (2) adding an antioxidant, organic silicon, and halogen-free flame retardant through a middle speed blender, and evenly blending in a middle speed to obtain a raw material composition; (3) automatically delivering the whole raw material composition into a vertical container, heating to a temperature of 120 DEG C, vacuumizing, and carrying out plasticization under a high stirring speed; (4) automatically transferring the materials to a double screw extruder, and extruding the materials at a temperature of 220 DEG C so as to obtain the highly filled halogen-free flame-retardant PP material. The provided calcium carbonate highly filled halogen-free flame-retardant PP material can reach the UL94V2 (0.8mm) level, the hardness is high, the shore hardness can reach 100 or more, the surface is smooth, the PP material does not contain any halogen and is environment-friendly, the cost is low, and the industrial production is possible.