EXTRUSION RAW MATERIAL FEEDING DEVICE AND METHOD OF PRODUCING OPTICAL TRANSMISSION BODY BY USING EXTRUSION RAW MATERIAL FEEDING DEVICE

摘要

Provided is an extrusion raw material feeding device which is used suitably in melt extrusion molding, and also provided is a method of producing an optical transmission body wherein increase in the transmission loss of an optical signal is very little and essential productivity of extrusion molding method is ensured. An extrusion raw material feeding device (1) comprises a vertical hopper (2) which has a cooling section (3) and a heating and melting section (4) continuous to the underside thereof and houses a material rod (R), a cooling means (5) for cooling the cooling section (3), an electric heater (6) which heats the heating and melting section (4), and a gas pressurization means (7) for supplying molten plastic (M) sequentially to a die by the gas pressure. The heating and melting section (4) is formed in the shape of a cylinder having the inside diameter larger than the inside diameter of the cooling section (3) located thereabove so that the molten plastic (M) can spread in the heating and melting section (4). An annular gas pressurization surface (7a) is formed between the outer circumference of the material rod (R) and the outer circumference of the molten plastic (M).