| 摘要 |
<p>1319523 Coated corrugated paperboard INTERNATIONAL PAPER CO 14 Aug 1970 [21 Aug 1969] 39343/70 Headings B2E and B2L [Also in Division B5] A corrugated paperboard comprises two facing sheets 2, 4 with a corrugated core 6 therebetween, the corrugations of the core extending transversely across the facing sheets, and a film 8 of thermoplastic material extending. across the corrugations at at least one side edge thus forming a closure at the side edge. A method and apparatus for forming the edge sealed paperboard comprises feeding the board through a thermoplastics applicator 384 along at least one side edge of the board's path, the applicator having an upper wall 390, a lower wall 392 and means for supporting a heated thermoplastic material 396 which forms a film across the corrugations of the core as the board is fed through the applicator. In a further embodiment, the edges of the facing sheets are curved inwards towards each other, an applicator having arcuate upper and lower walls being used.</p> |
