PURPOSE: To replace the foaming agent gas remaining in an olefinic resin foamed plate with inorg. gas such as air within a short time by eliminating conventional inferior efficiency such that a product is kept for a long period of time up to delivery from the aspect of safety, especially, in a case using a combustible foaming agent until the foaming agent gas is replaced with air because the foaming agent gas remaining in the olefinic resin foamed plate is not simply replaced with air even when said plate is allowed to stand under atmospheric pressure for a month or more.
CONSTITUTION: Small holes 2 are bored in at least the single surface of a foamed plate 3 by a needle roll 2 having needles 1 on the peripheral surface thereof and the foamed plate 3 is subsequently pressed and compressed by pinch rolls 5,6 to replace the foaming agent gas remaining in the foamed plate 3 with inorg. gas such as air.
NAITO MASATO
GOKURAKU HIROYUKI
