自限温加热带生产工艺的研究

Study on the Production Technology of Self-limiting Temperature Heating Belt

将适量的聚乙烯（ＰＥ）和乙烯－乙酸乙烯酯共聚物（ＥＶＡ）与一定量的炭黑混合造粒，用塑料挤出机在１７０℃下挤出圆柱体，并引入两根裸铜线，通过牵引装置将圆柱体拉伸使其产生分子内应力，经一对辊筒压成带状．然后迅速冷却，使导电炭黑聚集在靠近带体表面层．最后挂上一层绝缘皮，便得到自限温加热带．

This paper introduces the production of self-limiting temperature heating belt. Thegrains are produced by extruding a molten mixture of polyethylene(PE),copolymer ofethylene and acetate(EVA),and carbon powder and then extruded into a molten cylindrcal body at 170℃ from the die at the outlet of an extruder,and two copper wires are ledinto a molten cylidrcal body,which is stretched by drawing installation to bring aboutinner stress in the molecules of the body,which is then pressed between nipping rolls toproduce a planar body.Then,it is cooled rapidly in Water,and the carbon powder isconcentrated near the surface of it. Finally,it is co vend with an insulation cover,andthe self-limiting temperature by self heating belt is produced.