PURPOSE: To prevent deformation of a disk in the laminating process by adhering a hot-melt type adhesive while sticking boards for disks are heated so as to straighten the disks from warpage due to application of the adhesive by heating the opposite surface to the adhered surface.
CONSTITUTION: A hot-melt type adhesive 8 is applied on the lower side of an upper disk 5a and on the upper side of the lower disk 5b of two polycarbonate disks. These disks are heated by heaters 9a, 9b to the temp. lower than the glass transition temp. of the resin of the disks but higher as possible so that the mechanical deformation of the disks appearing after application of the adhesive 8 is eliminated. Then the sticking boards disks 10, 11 in this state are made to approach to each other while heated and pressed with 100kg load. Thereby, disks 5a, 5b having little mechanical deformation can be obtd.
TOBISAWA TAKESHI
MIYAHARA TETSUKUNI
SHIMIZU HIROSHI
TSUKADA MASAKAZU
NIPPON KOKAN KK