| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for producing a cavity-containing resin molding that prevents breaking and has high reflectance. <P>SOLUTION: The method for producing a cavity-containing resin molding includes the steps of: performing melt extrusion of a thermoplastic resin composition; cooling and solidifying the thermoplastic resin film obtained by performing the melt extrusion; and stretching the thermoplastic resin film obtained by being cooled and solidified, in the conveyance direction. In the stretching step, (a) an upstream roller and a downstream roller having different speeds are used, (b) the speed ratio between the downstream roller and the thermoplastic resin film is 1.01-1.10, (c) when stretching stress is σ<SB POS="POST">1</SB>and breaking stress is σ<SB POS="POST">2</SB>, the following range is satisfied: σ<SB POS="POST">2</SB>×0.5≤σ<SB POS="POST">1</SB><σ<SB POS="POST">2</SB>, and (d) the thermoplastic resin film is stretched so that the thickness of the film becomes 1/2 or less in the range of 10 mm from the start point of the stretch. <P>COPYRIGHT: (C)2012,JPO&INPIT |
