Patent ID: 6776946
Filing Date: 2004-08-17
Classification: B29C,B29K

Abstract:
A rubber extruding method extruding a rubber extruded intermediate by discharging rubber from a discharge port of a die plate mounted to an outlet of an extruder, whereinsaid die plate has an inflow port through which rubber flows in from the extruder side, said discharge port, and a rubber flow path connecting said inflow port and said discharge port therebetween, wherein said discharge port is of a flat shape with a lower section having a smaller height and a higher section having a larger height and with a height varying along a width direction to thereby extrude said rubber extruded intermediate with a thickness varying along a width direction, in addition each extruding speed of said rubber extruded intermediate is made uniform at positions along a width direction thereof; and said die plate satisfies the following relation: (Ssi/Sso)>(Shi/Sho) wherein Sso in the relation is an area per unit width in said lower section,Ssi is an area at said inflow port through which rubber flowing through said area Sso per unit width in said lower section passes, Sho is an area per unit width in said higher section, and Shi is an area at said inflow port through which rubber flowing through said area Sho per unit width in said higher section passes.