ものづくりにおける安全の追求

第1回　製品トラブル解析手法と対策（事故と劣化）

抄録

The polymer materials, such as rubber and plastics, are easily degradable compared to metal materials, therefore, the degradation of polymer causes many troubles in products. The cause of such troubles must be studied immediately to take measures against a recurrence. Solution for the trouble is just not only aimed to satisfy the product liability but often useful for a development or improvement of products. Polymer materials, of course, have both of advantages and disadvantages in their physicochemical properties, however, most of the engineers do not well understand the disadvantages, which often lead a cause of trouble. Therefore, it is very important to know a disadvantage of polymer materials. For example, the accident of Space Shuttle Challenger is known to be caused by a fuel-leaking from some parts made of fluoro-elastomer (Viton), an extremely-low-cold-resisting polymer. In particular, moisture in the materials induces an extraction of antioxidant and hydrolysis of polymeric materials to promote the degradation, such as decrease in strength and bacterial damage. Therefore, rubber and plastic product must be carefully designed by considering what factor may cause trouble in actual use.