Abstract
Generally speaking, after the heated cement was packed in the paper bag (or at low humidity of atmosphere), the moisture content of paper would be fairly lowered. So, we tried to examine the relation between a few strength properties and moisture content of Clupak and Normal Japanese kraft paper and paper bag.
1) Decrease rate of elongation of machine direction (M. D.) of Clupak paper was not so different from that of elongation of cross direction (C. D.) of Normal kraft paper by changing moisture content of it.
But decrease rate of elongation of C. D. of Clupak paper was larger than that of elongation of each direction of the other papers.
2) Decrease rate of the product of tensile strength and elongation of M. D. or C. D. of Clupak paper was larger than that of each direction of Normal kraft paper by decreasing moisture content of it.
Specially, the absolute value of the product of C. D. of Clupak paper was lowest.
3) In the results of Face & Back drop test using small type of paper bag, Normal kraft paper bag with low moisture content decreased in a sixth and Clupak paper bag with low moisture content decreased in a eighth. Yet, Clupak paper bag had a little higher drop number to destruction.
4) In the results of Butt drop test, the strength of Clupak paper bag had sixty per cent of that of Normal kraft paper bag at 2.5% moisture content.
