| 摘要 |
PURPOSE:To obtain a stretched polypropylene film excellent in steam barrier property and moldability by a method in which a polypropylene is mixed with a petroleum resin or terpene resin containing no polar groups so as to condition its glass transition temperature to 10-80 deg.C. CONSTITUTION:A resin prepared by mixing 95-77wt% polypropylene with a petroleum resin (hydrogenated alicyclic petroleum resin, etc.) or terpene resin (hydrogenated beta-pinene, hydrogenated diterpene, etc.) containing no polar groups such as hydroxide group, carboxyl group, etc., is extruded into a film. The film is further subjected to a stretching process so as to condition its glass transition temperature Tg to 10-80 deg.C. When polypropylene is mixed with 5wt% or more petroleum resin or terpene resin, Tg becomes 10 deg.C or higher and the steam barrier property is raised. Also, when polypropylene is mixed with 23wt% or less petroleum resin or terpene resin, Tg becomes 80 deg.C or lower and the moldability is raised. The polypropylene film may be formed to a laminate structure by providing the films on both sides. |
