This study has examined a method for predicting the probability of fracture in the threaded portion of a PE bottle that is used as an eye dropper after repeated opening and closing of the cap. Assuming that the duration of guarantee required for the PE bottle is at least three years, a state in which the bottle containing a liquid solution had been stored for three years from its manufacturing was realized in an accelerated manner according to the time-temperature equivalent law.
A repeated test with this bottle was carried out under the conditions of various temperatures and various fastening torques using dozens of such bottles for each condition by repeating the opening and closing of the cap three times per day until the liquid solution leaked from the threaded portion. By analyzing the result thus obtained applying Weibull statistics, an attempt was made to predict the probability of fracture in the threaded portion resulting from opening and closing of the cap of the bottle. Consequently the following has been revealed.
1) Concerning the probability of fracture in the threaded portion after repeated opening and closing of the cap of the PE bottle, a prediction method applied to Weibull statistics has been proposed.
2) A fatigue rupture test for the threaded portion was carried out that involved opening and closing of the cap of the PE bottle under the conditions of various temperatures and fastening torques. By organizing the results thus obtained by using the Weibull distribution, it has been shown that the probability of fracture in the threaded portion is more greatly affected by fastening torques than by temperatures.
3) By using the data of fracture in the threaded portion resulting from opening and closing of the cap under the accelerating conditions of various temperatures and fastening torques, it has been estimated that the probability of fracture in the threaded portion is 6.27X10^-5% when a person has repeated opening and closing of the cap 150 times under the conditions of 25℃ and 20 N·cm in his or her daily life.

抄録全体を表示

二軸押出機を用いた溶融混練法によりポリスチレン/有機変性クレー系複合体の作製を試みた．本研究では，作製した複合体の特性に及ぼすオキサゾリン変性ポリスチレンを主成分としたマスターバッチを用いたマスターバッチプロセスの効果について，引張試験，X線回折測定，TEM観察及びDSC測定から検討した．その結果，マスターバッチ作製における有機変性クレーの含有率が20wt％において，初期弾性率とガラス転移温度が最大を示した．このことから，ポリスチレン/有機変性クレーを作製する際，マスターバッチ内における最適なクレーの含有量が存在すると考えられる．加えて，複合体の初期弾性率とガラス転移温度は，粘度の高いポリスチレンを用いたとき，より高い値を示した．

抄録全体を表示