An acoustic emission (AE) measurement system was applied to investigate micro failures that occurred during creep failure testing of handsheet from beaten hardwood pulp. AEs frequently occur at both points, around the start and around the end of creep failure testing. On the contrary, AEs occur rarely whole through the other creep failure testing period. Maximum amplitude distribution of AEs just before sheet breaking is broad and suggests that mixture of fiber bonds failures and fiber breakages as a mechanism of sheet failure. On the other hand, maximum amplitude of AEs at the other testing period is relatively low and suggests that failures of weak fiber bonds mainly occur testing period. The handsheet breaks by the same creep failure mechanism regardless of creep load, because little difference in AE maximum amplitude distribution for whole testing period was found irrespective of breaking time and creep load. According to a classification by Guthrie et,al., this creep failure mechanism corresponds to the low load-long time type mechanism due to fiber failures.

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Film material of the air bubble type cushions (example: TRICONE. etc.) is polyester-polyethylene laminate. and static electricity is easy to be generated by vibration in packing and during transportation. By applying an anti-electrostatic solvent on the surface, it is possible to obtain anti-electrostatic effect. But, evaluation on persistence of anti-electrostatic effect of the anti-electrostatic solvent is not carried out. In this paper, persistence of anti-electrostatic effect by the storage condition is evaluated. It is preserved in two different atmospheres that the test pieces are left in the room of fixed temperature and humidity with ventilation (we called an opened condition) and that they are left in the sealed bag with large number of homogeneous cushions (we called a sealed condition). Persistence of anti-electrostatic effect is evaluated at the surface resistivity. As the result, in the opened condition, surface resistivity value becomes about 18 times of initial value after 4800 hours. In the sealed condition, surface resistivity value becomes about 5 times of the initial value after 4800 hours and surface resistivity value tends to decrease after 4800 hours. From these facts, it is shown that it is affected by the storage condition in persistence of anti-electrostatic effect.

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