Abstract: A fumaric acid diester based resin containing a dipropyl fumarate residue unit and a fumaric acid diester residue unit having a C1 or C2 alkyl group, wherein in a retardation film composed of the resin, when a refractive index in the fast axis direction within the film plane is designated as nx, a refractive index in the film in-plane direction orthogonal thereto is designated as ny, and a refractive index in the thickness direction of the film is designated as nz, the respective refractive indices are satisfied with a relationship of (nx?ny<nz) and a relationship between a film thickness and an out-of-plane retardation measured at a wavelength of 550 nm and expressed by the specific equation is 4.5 nm/film thickness (?m) or more in terms of an absolute value.

Abstract: Optical compensation layers are provided which have an optically compensating function imparted thereto upon coating fluid application or upon coating fluid application and subsequent uniaxial stretching and which have a small wavelength dependence of retardation.

Abstract: To provide a retardation film and an optical compensation film which have excellent optical properties and are useful as a compensation film for compensating the contrast and viewing-angle characteristics of liquid-crystal displays and as an antireflection film.

Abstract: A fumaric acid diester based resin containing a dipropyl fumarate residue unit and a fumaric acid diester residue unit having a C1 or C2 alkyl group, wherein in a retardation film composed of the resin, when a refractive index in the fast axis direction within the film plane is designated as nx, a refractive index in the film in-plane direction orthogonal thereto is designated as ny, and a refractive index in the thickness direction of the film is designated as nz, the respective refractive indices are satisfied with a relationship of (nx?ny<nz) and a relationship between a film thickness and an out-of-plane retardation measured at a wavelength of 550 nm and expressed by the specific equation is 4.5 nm/film thickness (?m) or more in terms of an absolute value.

Abstract: Optical compensation layers are provided which have an optically compensating function imparted thereto upon coating fluid application or upon coating fluid application and subsequent uniaxial stretching and which have a small wavelength dependence of retardation.

Abstract: To provide a retardation film and an optical compensation film which have excellent optical properties and are useful as a compensation film for compensating the contrast and viewing-angle characteristics of liquid-crystal displays and as an antireflection film.

Abstract: An aromatic amide block copolymer containing a specific aromatic amide compound unit and having a weight average molecular weight, as reduced into standard polystyrene measured by the gel permeation chromatography, of from 10,000 to 1,000,000.

Abstract: The present invention provides a branched polyvinyl imidazoline acid salt which, when used in waste water treatment, especially sewage treatment, forms flocs and decreases the water content of a dehydrated cake, a polymeric flocculent comprising the branched polyvinyl imidazoline acid salt, and a process for preparing the branched polyvinyl imidazoline acid salt. The branched polyvinyl imidazoline acid salt has a Huggins' constant k? of 0.2 to 1.2 and an intrinsic viscosity [?] of 2 to 20 based on measurements at 30° C. in a 0.1 mol/l aqueous solution of sodium chloride.

Abstract: An aromatic amide block copolymer containing a specific aromatic amide compound unit and having a weight average molecular weight, as reduced into standard polystyrene measured by the gel permeation chromatography, of from 10,000 to 1,000,000.

Abstract: The present invention provides a branched polyvinyl imidazoline acid salt which, when used in waste water treatment, especially sewage treatment, forms flocs and decreases the water content of a dehydrated cake, a polymeric flocculent comprising the branched polyvinyl imidazoline acid salt, and a process for preparing the branched polyvinyl imidazoline acid salt. The branched polyvinyl imidazoline acid salt has a Huggins' constant k′ of 0.2 to 1.2 and an intrinsic viscosity [&eegr;] of 2 to 20 based on measurements at 30° C. in a 0.1 mol/l aqueous solution of sodium chloride.

Abstract: An ester-amide block copolymer of the formula (1): ##STR1## wherein R is an aromatic hydrocarbon group with 6-20 carbon atoms and G is a residue of an aliphatic polyester, an aliphatic polycarbonate, an aliphatic polyethercarbonate or a polyorganosiloxane, and having a weight average molecular weight of 30,000-1,000,000. This copolymer is advantageously prepared by polycondensing an activated acyl lactam-terminated aromatic amide of the formula (2) with a diol of the formula (3) by bulk polymerization in a molten state: ##STR2## wherein R and G are the same as defined above.