Method for extruding plastic panel, flesnel lens comprising plastic panel and solar collector having fresnel lens

PURPOSE: To obtain the high reproduction accuracy of an embossing roll in a finely structured surface by obtaining a coextrudate from a highly basic molding material and a low viscosity molding material through two extruders and structuring the surface thereof through a three-roll polishing machine. CONSTITUTION: A panel material is produced as a coextrudate CX comprising a highly viscous basic molding material BF and a low viscosity molding material NF extruded on the molding material BF by using an extrusion apparatus equipped with a three-roll polishing machine having two extruders and embossing rolls. That is, the basic molding material BF of a main extruder 1 and the low viscosity molding material NF in a co-extruder 2 are together introduced into a coextrusion tool 3. This coextrudate CX is guided through the three-roll polishing machine comprising rolls 4, 5, 4' and the intermediate roll 5 is used as an embossing roll and the surface 7 thereof is formed into the negative shape of a panel surface 8 and a roll gap 6 is provided between the rolls 4, 5. This panel 10 is fed through a support roll 11. COPYRIGHT: (C)1995,JPO