| 摘要 |
PROBLEM TO BE SOLVED: To provide a polystyrene resin foam sheet for an openable and closable lunch box, wherein a surface part, which is left unprocessed in V-grooving, can stand repetitive bending motion at corners of the lunch box, its production method and the lunch box. SOLUTION: The polystyrene resin foam sheet A for the lunch box has the sheet surface part, which is left unprocessed in V-grooving, showing a tensile strength of 6.5-9.0 MPa and a density of 0.13-0.17 g/cm<SP>3</SP>. The lunch box is assembled by forming V-grooves B along lines corresponding to the corner of the assembled lunch box, leaving 0.05-0.2 mm from the sheet surface unprocessed, and bending the V-grooves to assemble the sheet into a box. COPYRIGHT: (C)2005,JPO&NCIPI |
