| 摘要 |
A bottom structure for a paper box for liquids is disclosed, which is made of a heat-sealabie paper sheet blank having four side portions (1 to 4) and four bottom portions (6 to 9). A pair of opposed ones (7, 9) of the bottom portions constitute an outermost layer of the bottom structure when the paper box is formed. The other pair of opposed bottom portions (6, 8) respectively have right isosceles triangular portions (6A, 8A) and fold-back portions (6B, 6C, 8B, 8C). The fold-back portions (6B, 6C, 8B, 8C) are adapted such that the entire length of their edges parallel to fold lines (e, f) between the corresponding side portions (1, 3) and bottom portions (6, 8) abut with the mating ones uniformly when they are folded back along their fold-back lines (i to l). |
