| 摘要 |
PURPOSE:To enhance reliability and the water resistance of a collection and drainage material for water by a method wherein a high-density sheet, having a two or three-dimentional netlike structure, and a low-density sheet having a three-dimentional netlike structure are laminated together, and the product is wound is a roll. CONSTITUTION:A high-density sheet having a two or three-dimentional netlike structure, which has a bulk density of 0.05-0.8g/cm<2> and thickness of 0.2-50mm., is made of fiber, wood wool, synthetic resin, etc. In the meantime, a low-density sheet 2 having a three-dimentional netlike structure, having a bulk density of 0.01-0.3g/cm<2> which is lower than that of said high-density sheet 1, and thickness of 5-250mm., is made of fiber, wood wool, etc. Said high-density sheet 1 and low- density sheet 2 are laminated together, and the product is wound is a roll to form the collection and drainage material for water. Thus, the product obtains a high reliability and durability because the sheets 1 and 2, positioned at the center part, has a collecting and draining function even when the collection and drainage material is filled up with the sediment. |
