| 主权项 |
1. A plastic pencil comprising:
a) a writing core; b) an interlayer coating material placed about the writing core; c) a porous casing enclosing the interlayer coating material on the writing core; d) a coating applied to the exterior surface of the porous casing; e) a lining applied on the coating of the porous casing; and f) wherein the writing core consists of a formulation composition comprising 0.1%-15% by weight of talcum powder, 0.1%-15% by weight of calcium carbonate, 5%-25% by weight of calcium stearate, 0.1%-5% by weight of low density polyethylene, 0.1%-5% by weight of palm oil, 0.1%-15% by weight of epoxy resin, 0.10%-40% by weight of styrene acrylonitrile and 5%-25% by weight of titanium dioxide with 40%-80% by weight of graphite added for black lead and 5%-25% by weight of color pigment/coloring agent for colored lead which are mixed in a high speed mixture, whereby the color core raw materials are further compounded using a co-rotating twin screw extruder where then the mixture is extruded and pelletized into free flowing pellets thereby forming the writing core. |
