In order to study paper strength reduction on recycling and the effect of hemicellulose on the decrease of specific bond strength during recycling, handsheets made from prehydrolyzed kraft pulp for dissolving were repeatedly recycled up to 30 times with and without disintegration. The results were compared with those from kraft pulp for papermaking. The effects of recycling with and without disintegration on the fundamental properties of dissolving pulp fibers and paper made from them were quite similar to those of papermaking pulp. The effect of hemicellulose on the specific bond strength with recycling may be negligible. The decrease of external fibrillation due to disintegration during paper recycling affected CSF and WRV and could cause a decrease of specific bond strength, resulting in further strength reduction of paper after several times recycling.

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The compression test is divided two ways of method and both are given the different load factor. The compression test has a purpose to know that the packaged product is able to hold the load and protect the contents or not. If compression displacement quantity is large, the risk, that load is handed down to contents, will increases. If these two test methods compression displacement has a difference, it cannot measure the buckling possibility only for one method. In this study, these two compression test are carried out, compared the test result and considered　equivalence.

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A new method of the drop test has been proposed as ‘The Hybrid Drop Test’. The purpose of this test is to evaluate the cushioning package design without the damage of the test specimen by the drop test. On this test, the predictive acceleration of the target drop height is calculated by the result of the safety drop test from the low drop height. The high efficacy of this test has been confirmed in the prior study. However, there is a problem that expensive equipments, such as shock machine, simulation software and acceleration measurement system, are needed to carry out this test. In order to become more useful test, the new simple method with the free fall tester and acceleration measurement equipment was proposed and investigated in this paper. As the result, the accuracy of the predictive acceleration was within 15 % toward the peak acceleration by the drop test. Moreover, it has suggested that there is a relatively slight influence of the characteristic of the cushion materials.

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