PRODUCTION OF PHOTOGRAPHIC BASE

摘要

PURPOSE:To prevent the generation of the gel of a resin coated layer by extruding a polyolefin resin while injecting an inert gas near to the lower part of a hopper, thereby coating the base with the resin. CONSTITUTION:Plural spacings 11 of the size at which pellets do not come out of the spacings are bored to the circumference of the pipe wall which is smallest in diameter in the lower part of the hopper and the inert gas is injected toward the central part of the pipe to shut off the intrusion of oxygen. The size of the spacing is set at <=2mm, more preferably <=1mm. The spacings 11 may be circular or like slits and an inert gas stagnating chamber 10 is preferably so provided that the gas is uniformly injected. Any inert gases which are inert in the reaction with oxygen are usable as the inert gas to be used and nitrogen is more preferable in terms of cost. The flow rate of the gas is sufficient with the flow rate at which the air to be intruded together with the resin to be charged is shut off and may be adjusted in proportion to the increase or decrease of the rate at which the polyolefin pellets are fed to an extruder. The degradation in the productivity is obviated in this way and the generation of the gel of the resin coated layer is prevented as well.