| 摘要 |
PROBLEM TO BE SOLVED: To provide a main bar for grating made of a composite resin material and its manufacturing method for preventing interlayer exfoliation. SOLUTION: This main bar 2 is constituted by arranging a rigid resin material 73 and a flexible resin material 74 on a center side and an outer side, respectively, and is molded by extrusion in a mixed condition of both resin materials 73, 74 without forming a boundary face between both resin materials 73 and 74. This main bar 2 is manufactured as follows. That is, the rigid resin material 73 heated to have fluidity is poured into an extrusion molding passage 52 formed in an extrusion mold 50, the rigid resin material 73 is pushed out outside the extrusion mold 50 through a discharge port 62 for extrusion provided in the extrusion molding passage 52, and the flexible resin material 74 having fluidity is poured into an outer surface of the rigid resin material 73 on the downstream side of the rigid resin material 73 flowing in the extrusion molding passage 52 to form the mixed condition of both resin materials 73, 74 without forming the boundary face between both resin materials 73 and 74. COPYRIGHT: (C)2008,JPO&INPIT
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