| 摘要 |
<p>PROBLEM TO BE SOLVED: To secure stable cable passing of a conduit tube which has high flame retardancy and can be installed easily by using a resin composition prepared by adding specific amounts of magnesium hydroxide powder and aluminum hydroxide powder to an ethylene copolymer material. SOLUTION: A material prepared by mixing aluminum hydroxide powder and magnesium hydroxide power in an ethylene copolymer material, for example, the EEA(ethylene ethyl acrylate) material at a mixing ratio of, preferably, 25-55% is granulated into pellets and heated. Then a straight tube is formed by extrusion molding the heated pellets in a water tank. Therefore, the tube has high flame retardancy and only the external surface of the tube is less crystallized, soft, and easily bendable, because the surface is quickly cooled with the water. However, the internal surface of the tube becomes hard, because crystallization gradually advances and the degree of crystallization becomes higher inside the tube. Therefore, a non-halogen wire protective tube which can be installed easily and has a high cable passing property can be molded stably.</p> |
