| 摘要 |
A sealed letter-packet is formed by manufacturing the cover around the contents 2, one side of the cover consisting of paper 1 and the other side of a thermoplastic plastic film 3, welding together the film and paper around the contents at all four edges 9, 10,11 and 12 of the packet and providing the packet with perforation 13 within one welding area. <IMAGE> |
