Patent ID: 6896832

Claim:
The resin film forming method for extruding fused resin from an extruder die to form a resin film, comprising the steps of: fusing a first resin and a second resin to form said fused resin by providing at least one flow path near each end in a width direction of a discharge port of said extruder die such that each flow path is enveloped by said first resin and supplying said second resin to said flow paths; and extruding said fused resin from said extruder die to form said resin film, wherein said second resin joins said first resin so that said second resin is enveloped by said first resin and is extruded from the extruder die, wherein said second resin forms at least one continuous strand within said first resin and said second resin has an extension viscosity higher than that of said first resin.