METHOD FOR PRODUCING OPTICAL FILM

摘要

PROBLEM TO BE SOLVED: To provide a method for producing an optical film which is a thin-film and excellent in surface smoothness and combines high total light transmittance and high light diffusion property. SOLUTION: An optical film composed of a transparent resin and a metal oxide and having a total light transmittance of not less than 70%, a haze value of not less than 20% to less than 100% and a center line surface roughness (Ra) of not more than 100 nm is produced by a method which comprises (A) a step of subjecting a metal compound which will form a metal oxide through a sol-gel reaction to a sol-gel reaction in a solvent, (B) a step of preparing a solution containing a transparent resin as a solute, (C) a step of mixing the mixture produced in the step (A) and the solution produced in the step (B), and (D) a step of applying or spreading the mixture produced in the step (C) over a substrate or a container and then heating and permitting the solvent to be evaporated to thereby form a film with the proviso that a dimensionless SP value calculated by dividing an SP value ((cal/cm2)0.5) as a solubility parameter of the transparent resin as determined in accordance with the Hildebrand method by 1 (cal/cm2)0.5and a value calculated by adding 1 to an HLB value as a hydrophilic-lipophilic balance value of the metal oxide as determined by a given calculation process satisfy the relationship of formula (1) as follows: 2.1<(¾an HLB value + 1) - (a dimensionless SP value¾). COPYRIGHT: (C)2008,JPO&INPIT