| 摘要 |
PROBLEM TO BE SOLVED: To provide a filter having a layer with small uniformity coefficient (specifically, a waste plastic ball layer), waste plastic ball used for such layer, and a manufacturing method for the waste plastic.SOLUTION: A manufacturing method for a waste plastic ball 11 includes the steps of: forming a waste plastic rod-shaped member P1 composed of waste plastics; forming a waster plastic lump P2 by cutting the waste plastic rod-shaped member P1 in the predetermined length; and forming a ball-shaped waste plastic ball 11 by immersed the waste plastic rod-shaped lump P2 in cooling water. |
