| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the accumulation and separation of a coloring agent and filler, and also prevent them from adhering to a plastic sheet by giving decoration on the surface of base material of a melt-extruding plastic sheet, and forming the base material of a center layer with a coloring agent and filer kneaded and surface layers not containing a filler laminated on the front and rear of the center layer. SOLUTION: The base material 1 of a melt-extruding plastic sheet is made into a three-layer structure having a center layer 2 made by mixing and kneading a coloring agent and filler, and surface layers 3, 3', not containing at least a filler laminated on the front end rear of the center layer 2. The center layer 2 and surface layer 3, 3' are heat-welded each other by a co- extruding method. The center layer 2 is extruded by adding a coloring agent of 5-80 pts.wt. to 100 pts.wt. resin and/or by melt-kneading a filer with 5-80 pts.wt. at the same reference. A coloring agent of the surface layers 3, 3' are made 5-80 pts.wt. in the same manner. Also, for such a base material 1, it is suitable to employ a sheet of polyethylene, polypropylene, and polyolefin resin of a copolymer consisting mainly of these substances.</p> |
