| 摘要 |
PURPOSE:To provide a hydraulic cylinder excellent in surface roughness and strength by adding a chemical compound having stearoamide group to polyamide filled with an inorganic substance. CONSTITUTION:A chemical compound having stearoamide group which is a blend material, for example, ethylene bisstearoamide is mixed by 0.3-1.5wt% in a polyamide molding material in which an inorganic substance such as glass fiber, for example, fibrous glass reinforce 66 nylon is filled up by 15-60wt%. The molding material is molded by an injection molding machine 8. At the time of injection molding, glass fiber 20 is left at the central portion of a thickness of a cylinder, and resin is closely adhered to surfaces 7, 11 of a metal mold, so that the surface of a molded article is subjected to very little filling of an inorganic substance. Accordingly, the surface roughness of the molded article is remarkably improved, and as glass fiber which is reinforcing material stays in polyamide, the tensile strength is improved. |
