Abstract: A resin-impregnated base substrate is provided by immersing a sheet in an aromatic liquid crystal polyester solution composition so that the polyester is impregnated into the sheet, and removing the solvent. The composition comprises 20 to 50 parts by weight of an aromatic liquid crystal polyester and 100 parts by weight of an aprotic solvent having no halogen atom, wherein the sheet comprises fiber selected from the group consisting of polyolefin resin fiber, fluorocarbon resin fiber, aramid resin fiber, glass fiber, ceramic fiber and carbon fiber.

Abstract: A liquid-crystalline polyester for film having small linear expansibility and high flexibility is provided. The polyester may have structural units —O—Ar1-CO—, —NH—Ar2-X—, —CO—Ar3-CO— and —CO—Ar4-Z-Ar5-CO— wherein Ar1 represents 1,4-phenylene, 2,6-naphthylene or 4,4?-biphenylene, Ar2 represents 1,4-phenylene or 1,3-phenylene, X represents —O— or —NH—, Ar3 represents 1,4-phenylene, 1,3-phenylene or 2,6-naphthylene, Ar4 and Ar5 independently represent 1,4-phenylene, 2,6-naphthylene or 4,4?-biphenylene, and Z represents —O—, —SO2— or —CO—, in which the amount of monomer (1) is 30-80% by mol, the amount of monomer (2) is 10-35% by mol, the total amount of monomers (3) and (4) is 10-35% by mol and the amount of monomer (4) is 1% by mol or larger.

Abstract: A liquid-crystalline polyester for film having small linear expansibility and high flexibility is provided. The polyester may have structural units —O—Ar1-CO—, —NH—Ar2-X—, —CO—Ar3-CO— and —CO—Ar4-Z-Ar5-CO— wherein Ar1 represents 1,4-phenylene, 2,6-naphthylene or 4,4?-biphenylene, Ar2 represents 1,4-phenylene or 1,3-phenylene, X represents —O— or —NH—, Ar3 represents 1,4-phenylene, 1,3-phenylene or 2,6-naphthylene, Ar4 and Ar5 independently represent 1,4-phenylene, 2,6-naphthylene or 4,4°-biphenylene, and Z represents —O—, —SO2— or —C—, in which the amount of monomer (1) is 30-80% by mol, the amount of monomer (2) is 10-35% by mol, the total amount of monomers (3) and (4) is 10-35% by mol and the amount of monomer (4) is 1% by mol or larger.

Abstract: A resin-impregnated base substrate is provided by immersing a sheet in an aromatic liquid crystal polyester solution composition so that the polyester is impregnated into the sheet, and removing the solvent. The composition comprises 20 to 50 parts by weight of an aromatic liquid crystal polyester and 100 parts by weight of an aprotic solvent having no halogen atom, wherein the sheet comprises fiber selected from the group consisting of polyolefin resin fiber, fluorocarbon resin fiber, aramid resin fiber, glass fiber, ceramic fiber and carbon fiber.