| 摘要 |
PURPOSE:To form excellent surface properties, and to increase strength by placing between outer layers a high-molecular material plate containing a specific quantity of reinforcing fibers and rolling a blank, both surfaces of which are composed of a normal high-molecular material plate and which has three layer structure, in the two direction. CONSTITUTION:In a high molecular material having three layer structure, an outer layer 1 consists of a normal high molecular material used for improving surface properties such as polypropylene, and an inner layer 2 is made up of fiber reinforced plastics containing not more than 40wt.% glass fibers, carbon fibers, ceramic fibers, etc., having strength such as polypropylene + glass. The high molecular material is rolled in one direction in a temperature range just under the melting point of the high molecular material, and the direction of rolling is changed at 90 deg.C and rolling in the two directions is conducted. Accordingly, strength isotropy is acquired at the same stretch ratio in an inner layer material having reinforcing fibers and an outer layer material as a pure high molecular material, no reinforcing fiber is exposed on a surface, and an excellent surface state equal to a general pure resin is displayed. |
