Solution casting apparatus and method

A solution casting apparatus comprising:

• a casting drum continuously rotating;
• a casing housing said casting drum;
• a casting die for discharging a dope containing a polymer and a solvent as a casting bead onto a peripheral surface of said casting drum;
• a peeling roller for peeling a casting film as a wet film from said casting drum, said casting film being formed by solidifying said dope, and said wet film being dried to be a film;
• a first partition member provided in an upstream side from said casting die in a rotational direction of said casting drum in said casing, said first partition member being approximately parallel to said casting die;
• a second partition member provided in a downstream side from said casting die in the rotational direction of said casting drum in said casing, said second partition member being approximately parallel to said casting die;
• a third partition member provided in a downstream side from said second partition member in the rotational direction of said casting drum in said casing, said third partition member being approximately parallel to said casting die;
• a chamber formed by said first partition member and said second partition member in said casing so as to surround said casting die;
• a side labyrinth seal portion provided so as to be close to a side end surface of said casting drum, for preventing dry air from entering said chamber through the side end surface of said casting drum;
• a clearance adjuster for adjusting a clearance between said side labyrinth seal portion and the side end surface of said casting drum;
• a dry air supply duct provided in an upstream side from said peeling roller in the rotational direction of said casting drum;
• a dry air exhaust duct provided at the vicinity of said second partition member outside said chamber;
• and
• a dry air circulator provided outside said casing, for circulating dry air between a said dry air supply duct and said dry air exhaust duct, wherein a speed of air blowing from outside to said chamber through said side labyrinth seal portion is set to at most 5 m/sec at said side labyrinth seal portion,
• wherein a first labyrinth seal portion is provided on said first partition member between said first partition member and the peripheral surface of said casting drum,
• wherein a speed of air blowing from outside to said chamber through said first labyrinth seal portion provided on said first partition member is set to at most 10 m/sec at said first labyrinth seal portion,
• wherein a second labyrinth seal portion is provided on said second partition member between said second partition member and the peripheral surface of said casting drum,
• wherein a speed of air blowing from outside to said chamber through said second labyrinth seal portion provided on said second partition member is set to at most 5 m/sec at said second labyrinth seal portion,
• wherein a third labyrinth seal portion is provided on said third partition member between said third partition member and the peripheral surface of said casting drum, and
• a speed of air blowing from outside to said chamber through said third labyrinth seal portion provided on said third partition member is set to at most 10 m/sec at said third labyrinth seal portion.