Patent ID: 7780430

Claim:
A mandrel that comes into proximity or contact with the surface of a moving resin film to guide the movement of the resin film when a resin film in continuous form is continuously produced, the mandrel comprising: a mandrel main body having an opening, the opening defining an internal space and a fluid retention part; and a guide part that is composed of an elastic member attached to the opening and having a plurality of pores, and that can advance and retract relative to the resin film, wherein an internal space is formed between the guide part and the mandrel main body, and fluid seepage means is provided in the internal space so as to allow fluid to seep out through the side facing the internal space via the pores, a fluid supply and drainage part for supplying the fluid to the fluid retention part or for draining the fluid from the fluid retention part, the fluid retention part is partitioned by a partitioning wall into a first space communicated with the fluid supply and drainage part and a second space communicated with the pores in the guide part, and a communicating part for communicating the first space with the second space is provided along the extending direction of the partitioning wall to the partitioning wall.