| 摘要 |
PROBLEM TO BE SOLVED: To enable the rolling-up of a foam sheet so that no gauge bands are generated and neither are creases or flares generated in the foam sheet after it is spread by rocking a widening device in the sheet width direction. SOLUTION: A sheet widening device 6 is rocked in the sheet width direction. That is, a foamable sheet 11 is pinched under pressure and conveyed by a pair of pressing rolls 31, then is caused to pass through a thin gap path 21 to be guided into a heating furnace 2, and is preheated using a preheater 4. Further, the sheet 11 is caused to pass through a heating device 5 to obtain a thermoplastic resin foam sheet 12. This foam sheet 12 is widened by the widening device 6 installed between the latter half and the end point of a foaming stage and then is conveyed to the outside of the heating furnace 2 after passing through a thin gap path 22. This widening device 6 is rocked in the sheet width direction. The rocking operation is performed at a surface temperature of 50-150 deg.C, preferably at a rocking speed of 2.5-1200 mm/min. The rocking width is preferably 40-200 mm. |
