| 摘要 |
PURPOSE:To provide a polypropylene compsn. suitable for use in press-through package and having excellent transparency, thermoformability and safety, by incorporating a specified petroleum resin in a polypropylene resin. CONSTITUTION:A hydrogenated petroleum resin having a softening point of 124 deg.C or above is added to 100pts.wt. polypropylene. The quantity of the petroleum resin varies depending on the softening point, but is usually 3-20pts.wt., pref. 6-11pts.wt. per 100pts.wt. polypropylene. When the quantity is less than 3pts.wt., no satisfactory effect of improving transparency and thermoformability can be obtd., while when it exceeds 20pts.wt., thermoformability is deteriorated. Examples of the polypropylene resins are homopolymers and random copolymers of propylene with alpha-olefins, among which copolymers having a melt flow index of 1-4 as measured according to JIS K7210, method of condition 14 and homopolymers are preferred from the viewpoints of well-balanced properties between transparency and moldability. |
