Abstract: A cellulosic ester resin modifier for producing a cellulosic ester film, which facilitates obtaining a film that remains transparent even when exposed to high-humidity and high-temperature environments, and with which it is possible to obtain a film having excellent water vapor permeability resistance, and dimensional stability against heat. The present invention also provides a cellulosic ester resin composition using the modifier, a method for producing a polarizing-plate protective film, and a liquid crystal display device, and provides a cellulosic ester resin modifier including a polyester polyol (A) having a phthalic acid residue and an aliphatic glycol residue having 2 to 3 carbon atoms in a main chain skeleton and a diester (B) having an aliphatic glycol having 2 to 3 carbon atoms and an aromatic monocarboxylic acid, in which a mass ratio of [(A)/(B)] is in a range of 90/10 to 60/40.

Abstract: A cellulosic ester resin modifier for producing a cellulosic ester film, which facilitates obtaining a film that remains transparent even when exposed to high-humidity and high-temperature environments, and with which it is possible to obtain a film having excellent water vapor permeability resistance, and dimensional stability against heat. The present invention also provides a cellulosic ester resin composition using the modifier, a method for producing a polarizing-plate protective film, and a liquid crystal display device, and provides a cellulosic ester resin modifier including a polyester polyol (A) having a phthalic acid residue and an aliphatic glycol residue having 2 to 3 carbon atoms in a main chain skeleton and a diester (B) having an aliphatic glycol having 2 to 3 carbon atoms and an aromatic monocarboxylic acid, in which a mass ratio of [(A)/(B)] is in a range of 90/10 to 60/40.

Abstract: For providing a resin composition for an optical material which exhibits less change in birefringence due to external force and which is suitable for use in the production of an optical member; an optical film obtained by using the resin composition; and a liquid crystal display device using the same, provided is a resin composition containing a polycarbonate resin (X); and a polyester resin (Y) whose number average molecular weight is 200 to 2,000 and which is represented by General Formula (1): B-(G-A)n-G-B (wherein B represents an aryl monocarboxylic acid residue having 6 to 12 carbon atoms or an aliphatic monocarboxylic acid residue having 1 to 8 carbon atoms.

Abstract: For providing a resin composition for an optical material which exhibits less change in birefringence due to external force and which is suitable for use in the production of an optical member; an optical film obtained by using the resin composition; and a liquid crystal display device using the same, provided is a resin composition containing a polycarbonate resin (X); and a polyester resin (Y) whose number average molecular weight is 200 to 2,000 and which is represented by General Formula (1): B-(G-A)n-G-B (wherein B represents an aryl monocarboxylic acid residue having 6 to 12 carbon atoms or an aliphatic monocarboxylic acid residue having 1 to 8 carbon atoms.