Abstract: A liquid crystal polyester comprising a repeating unit (A1) represented by the formula (A1) and a repeating unit (A2) represented by the formula (A2). A molar ratio (phenolic hydroxyl groups derived from the repeating unit (A2)/phenolic hydroxyl groups derived from the repeating unit (A1)) is 1 or lower, as calculated by 1H-NMR. A ratio [repeating unit (A2)/repeating unit (A1)] is 1.2 or larger. The number of the repeating unit (A1) is 20% or more and the number of the repeating unit (A2) is 58% or more based on 100% of a total number of all repeating units of the liquid crystal polyester. A flow starting temperature of the liquid crystal polyester is 250° C. or more. —O—Ar11—CO—??(A1) —O—Ar12—CO—??(A2) Ar11 represents a phenylene group and Ar12 represents a naphthylene group. A hydrogen atom is optionally substituted.

Abstract: A liquid crystal polyester comprising a repeating unit (A1) represented by the formula (A1) and a repeating unit (A2) represented by the formula (A2). A molar ratio (phenolic hydroxyl groups derived from the repeating unit (A2)/phenolic hydroxyl groups derived from the repeating unit (A1)) is 1 or lower, as calculated by 1H-NMR. A ratio [repeating unit (A2)/repeating unit (A1)] is 1.2 or larger. The number of the repeating unit (A1) is 20% or more and the number of the repeating unit (A2) is 58% or more based on 100% of a total number of all repeating units of the liquid crystal polyester. A flow starting temperature of the liquid crystal polyester is 250° C. or more. —O—Ar11—CO—??(A1) —O—Ar12—CO—??(A2) Ar11 represents a phenylene group and Ar12 represents a naphthylene group. A hydrogen atom is optionally substituted.

Abstract: A liquid crystal polyester comprising a repeating unit derived from an aromatic hydroxycarboxylic acid. The content of the repeating unit derived from an aromatic hydroxycarboxylic acid is 80% or more based on 100% of a total number of all repeating units of the liquid crystal polyester. The repeating unit derived from an aromatic hydroxycarboxylic acid comprises a repeating unit (A1) represented by the formula (A1) and a repeating unit (A2) represented by the formula (A2). A ratio [repeating unit (A2)/repeating unit (A1)] is 1.2 or larger. A molar ratio [phenolic hydroxyl groups/(the phenolic hydroxyl groups+acyl groups)] is 0.3 or lower, as calculated by 1H-NMR. —O—Ar11—CO—??(A1) —O—Ar12—CO—??(A1) Ar11 represents a phenylene group and Ar12 represents a naphthylene group. A hydrogen atom is optionally substituted.

Abstract: A liquid crystal polyester comprising a structural unit derived from 6-hydroxy-2-naphthoic acid, wherein in thermal extraction GC-MS analysis of the liquid crystal polyester under the following measuring conditions, the relative content of the following impurity component determined from the GC peak area in the total ion chromatogram using methyl 6-hydroxy-2-naphthoate as a standard sample is 50 ppm or less based on the mass of the liquid crystal polyester, and the impurity component has main peaks at m/z=228, 186, 171, and 143 in the MS spectrum chart and a retention time detected in the range of 11.5 to 12.5 min in the total ion chromatogram.

Abstract: An object of the present invention is to provide a polyamideimide resin for an optical member having both high flexibility and bending resistance, and in particular, a polyamideimide resin for a front plate of an image display apparatus, and an optical member such as a front plate containing the polyamideimide resin.

Abstract: A polymer compound comprising a constitutional unit represented by the following formula (1) and a constitutional unit represented by the following formula (X) and/or a constitutional unit represented by the following formula (Y), wherein the content of the hydroxyl groups contained in the polymer compound is less than 0.02 mol %: Ar1??(1) [wherein, Ar1 represents an arylene group and this group optionally has a substituent.] [wherein, aX1 and aX2 each independently represent an integer of 0 or more. ArX1 and ArX3 each independently represent an arylene group or a divalent heterocyclic group and these groups each optionally have a substituent. ArX2 and ArX4 each independently represent an arylene group, a divalent heterocyclic group or a divalent group in which at least one arylene group and at least one divalent heterocyclic group are bonded directly to each other, and these groups each optionally have a substituent.

Abstract: An object of the present invention is to provide a polyamideimide resin for an optical member having both high flexibility and bending resistance, and in particular, a polyamideimide resin for a front plate of an image display apparatus, and an optical member such as a front plate containing the polyamideimide resin.

Abstract: A polymer compound comprising a constitutional unit represented by the following formula (1) and a constitutional unit represented by the following formula (X) and/or a constitutional unit represented by the following formula (Y), wherein the content of the hydroxyl groups contained in the polymer compound is less than 0.02 mol %: ?Ar1???(1) wherein Ar1 represents an arylene group and this group optionally has a substituent, wherein, ArY1 represents an arylene group, a divalent heterocyclic group or a divalent group in which at least one arylene group and at least one divalent heterocyclic group are bonded directly to each other, and these groups each optionally have a substituent.