| 摘要 |
A bag of tubular form open at one end and closed at the other end, comprising a plurality of contiguous plies of paper bonded together adjacent each of said ends, and an innermost ply of heat sealable plastic material lightly bonded adjacent said bag ends to the contiguous paper ply for manual detachment therefrom, said bag being longitudinally and reversely creased along diametrically opposed portions to provide a pair of oppositely disposed gussets interposed between front and rear wall portions, at least some of the inner plies being stepped progressively upward with respect to the outer ply in the front wall portion at the open bag end, at least the outermost ply being stepped upwardly with respect to the innermost ply in the rear wall portion at the open bag end to provide an exposed overlap rear wall portion with respect to the innermost ply of said front wall portion, at least portions of said gussets terminating at said open bag end within said overlap to provide exposed portions thereof, said overlap rear wall and exposed gusset portions being coated with an adhesive at said open bag end, the bag construction at said closed end being the reverse of that at the open end said plastic ply being heat sealed to closure adjacent said closed bag end, the bag closure at said end being otherwise completed by coating the exposed overlapping rear wall portion and exposed gusset portions with an adhesive and folding over with said sealed end of said plastic ply and sealed to closure against the opposite wall portion, said bonding together of said paper plies at said end thereby imparting to said closure the combined strength of all such plies, the open end of said bag being adapted for heat sealing of said plastic ply and closure similarly to that of said closed end and said bag when so closed at both ends being sift and leak proof and resistant to insect penetration, and being adapted for opening of said paper plies and removal of said plastic ply intact.
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