| 摘要 |
PURPOSE:To prepare the titled waste water treating material narrow in particle size distribution at the time of preparation and high in product yield, by supplying a mixture of a thermoplastic org. polymer, an inorg. compound and a decomposable blowing agent to a melting extruder to extrude the same which cutting the extrudate into an appropriate length. CONSTITUTION:25wt% or more of a thermoplastic org. polymer (e.g., polyethylene) and 75wt% or less of an inorg. compound (e.g., barium sulfate) are used as base components and 0.2-5.0wt% of said base components of a decomposable blowing agent such as azodicarbonamide is added to and mixed with said base components. The resulting mixture is supplied to a melting extruder wherein the max. temp. of a cylinder is the decomposition temp. of the blowing agent or more and extruded from a nozzle having a circular shape with a diameter of 0.5-3.0mm. or a profile shape having the same cross- sectional area while the extrude is cut into a length 0.3-3.0 times the diameter of the nozzle when the shape thereof is circular. As a result, the titled waste water treating material narrow in particle size distribution at the time of preparation, high in product yield, having a porous surface and large available surface area and high in contact efficiency with a substance to be removed is obtained. |
