Roll of polyvinyl alcohol film and polarizing film prepared therefrom
View Patent ↗A polyvinyl alcohol film roll including a cylindrical core tube made of a metallic material and having a surface roughness of at most 100 S and a polyvinyl alcohol film wound up around the cylindrical core tube, the film roll being obtained by forming the film from a solution of a polyvinyl alcohol resin and winding up the film around the core tube, and the film roll being capable of providing an optically homogeneous polyvinyl alcohol film having an excellent appearance.
1. A roll of a polyvinyl alcohol film obtained by winding up the polyvinyl alcohol film around a cylindrical core tube after forming the film from a solution of a polyvinyl alcohol resin, wherein the cylindrical core tube is made of a metallic material and has a surface roughness (Ra) of at most 100 μm, a roundness of 0.01 to 0.2 mm and a cylindricality of 0.01 to 1 mm, and wherein a thickness of said polyvinyl alcohol film is 20 to 100 μm.
2. The roll of claim 1 , wherein said cylindrical core tube has an outer diameter of 75 to 210 mm and a length of 0.5 to 4.0 m.