Patent ID: 8357742

Claim:
A resin composition for a vibration damping material, comprising: a polyester resin mainly formed of a dicarboxylic acid constitutional unit and a diol constitutional unit; and a filler, wherein: (1) the polyester resin contains 50 mol % or more of a dicarboxylic acid constitutional unit (A) derived from an aromatic dicarboxylic acid in all dicarboxylic acid constitutional units, and contains 70 mol % or more of a dicarboxylic acid constitutional unit derived from isophthalic acid in the dicarboxylic acid constitutional unit (A) derived from an aromatic dicarboxylic acid; (2) the polyester resin contains 60 mol % or more of a diol constitutional unit (B) derived from ethylene glycol in all diol constitutional units; (3) the polyester resin contains a constitutional unit (C) formed of an aliphatic dicarboxylic acid, an aliphatic diol, and/or an aliphatic hydroxycarboxylic acid all of which have 5 or more carbon atoms, and a total of the constitutional unit is 5 to 25 mol %; (4) the polyester resin contains a total of 75 mol % or more of the constitutional units (A), (B), and (C) in all constitutional units of the polyester resin; (5) an intrinsic viscosity of the polyester resin, which is measured at 25° C. in a mixed solvent of tetrachloroethane and phenol at a mass ratio of 1 to 1, is 0.2 to 2.0 dL/g; (6) a calorie of crystallization exotherm peak under temperature drop conditions of the polyester resin, which is measured by a differential scanning calorimeter, is 5 J/g or less; (7) the resin composition contains, as the filler, a flake-like or plate-like filler (D) and a filler (E) made of a particulate metal oxide, in which a content of the filler (D) is 18 to 70 mass %, a content of the filler (E) is 2 to 20 mass %, and a total content of the fillers (D) and (E) is 20 to 80 mass %; and (8) a maximum value of a loss elastic modulus of the resin composition is 5×10 8 [N/m 2 ] or more.