Abstract: Provided is a polymer material containing at least one kind of a cellulose derivative having (a) an organosilyl group (the organosilyl group having a first aliphatic group, an unsaturated aliphatic group, or an aromatic group), and (b) an acyl group or a second aliphatic group.

Abstract: The retardation film according to the present invention is characterized by: including a polymer material that includes at least one cellulose derivative which includes specific monomer units: having an in-plane retardation Re(550) of 105-160 nm, reverse wavelength dispersion property, Re(450)/Re(550), of 0.80-0.89, and a thickness of 20-50 ?m; and containing inorganic particles. In particular, the present invention exhibits the effect of reducing the photoelastic coefficient.

Abstract: Provided are: a novel retardation film which has low photoelastic coefficient, while having good linear thermal expansion coefficient and water absorption; and the novel retardation film which additionally has high heat resistance. The above-described problem is solved by a retardation film which has an absolute value of the linear thermal expansion coefficient of 100 ppm/° C. or less, a glass transition temperature of 180° C. or more, a photoelastic coefficient of from 5×10?12 m2/N to 30×10?12 m2/N and a water absorption of 2.0 wt % or less, or a retardation film which has an absolute value of the linear thermal expansion coefficient of 100 ppm/° C. or less, a photoelastic coefficient of from 5×10?12 m2/N to 30×10?12 m2/N and a water absorption of 2.0 wt % or less.

Abstract: Provided is a polymer material containing at least one kind of a cellulose derivative having (a) an organosilyl group (the organosilyl group having a first aliphatic group, an unsaturated aliphatic group, or an aromatic group), and (b) an acyl group or a second aliphatic group.

Abstract: The retardation film according to the present invention is characterized by: including a polymer material that includes at least one cellulose derivative which includes specific monomer units; having an in-plane retardation Re(550) of 105-160 nm, reverse wavelength dispersion property, Re(450)/Re(550), of 0.80-0.89, and a thickness of 20-50 ?m; and containing inorganic particles. In particular, the present invention exhibits the effect of reducing the photoelastic coefficient.

Abstract: The present invention achieves a phase difference film that is excellent in wavelength dispersion property, in-plane retardation, and film thickness, by using a polymeric material (i) which is composed of at least one type of cellulose derivative having a specific alkoxyl group substitution degree D1 and a specific 2-naphthoyl group substitution degree D2 and (ii) which has a specific total 2-naphthoyl group substitution degree D3.

Abstract: The present invention achieves a phase difference film that is excellent in wavelength dispersion property, in-plane retardation, and film thickness, by using a polymeric material (i) which is composed of at least one type of cellulose derivative having a specific alkoxyl group substitution degree D1 and a specific 2-naphthoyl group substitution degree D2 and (ii) which has a specific total 2-naphthoyl group substitution degree D3.

Abstract: The object of the present invention is to obtain the polyimide and the polyamic acid excellent in heat resistance, low thermal expansion property, and transparency and achieve low birefringence and to provide a product or a member, demanded to have high heat resistance and transparency, by using the polyimide or the polyamic acid. In particular, the object is to provide a product and a member in which the polyimide or the polyamic acid of the present invention is formed on a surface of an inorganic substance such as glass, metal, a metal oxide, or a single crystal silicon. The objects are attained by introducing a rigid structure and an alicyclic structure into a skeleton and using a monomer having a fluorene skeleton together.

Abstract: The object of the present invention is to obtain the polyimide and the polyamic acid excellent in heat resistance, low thermal expansion property, and transparency and achieve low birefringence and to provide a product or a member, demanded to have high heat resistance and transparency, by using the polyimide or the polyamic acid. In particular, the object is to provide a product and a member in which the polyimide or the polyamic acid of the present invention is formed on a surface of an inorganic substance such as glass, metal, a metal oxide, or a single crystal silicon. The objects are attained by introducing a rigid structure and an alicyclic structure into a skeleton and using a monomer having a fluorene skeleton together.