Patent ID: 7921961

Claim:
A vibration-deadening material, comprising: a multilayer structure comprising an intermediate layer, a first metal sheet, and a second metal sheet, wherein the intermediate layer comprises a viscoelastic resin composition provided between the first metal sheet and the second metal sheet, and wherein: (i) the viscoelastic resin composition comprises a thermosetting resin which includes an amorphous copolymerizable polyester resin and a curing agent, wherein the amorphous copolymerizable polyester resin includes a polycarboxylic acid chosen from at least one of adipic acid, sebacic acid, dimer acid, hydrogenated dimer acid, or alkenylsuccinic acid in an amount of between approximately 5 mol % to approximately 50 mol % in whole polycarboxylic acid components, the amorphous copolymerizable polyester resin further including aromatic dicarboxylic acid in an amount of approximately 50 mol % or more in the whole polycarboxylic acid components, wherein the amorphous copolymerizable polyester resin includes a glass transition point temperature between approximately −40° C. and approximately −10° C., wherein a weight average molecular weight of the amorphous copolymerizable polyester resin is approximately 8,000 or more, a blended amount of the curing agent in the viscoelastic resin is approximately 3 parts by mass to approximately 35 parts by mass or more, with respect to 100 parts by weight of the amorphous copolymerizable polyester resin, and wherein the curing agents include at least one types of curing agents selected from the group consisting of polyepoxy compounds, acid anhydrides, and polyisocyanate compounds; (ii) a first surface of the first metal sheet and a second surface of the second metal sheet contact the viscoelastic resin composition; and (iii) each of the first and second surfaces includes a bonding undercoat comprising between about 5 and 50 mass % of silica, between about 5 and 50 mass % of a polyester resin having a glass transition point temperature of approximately 0° C. or greater, between about 1 and 50 mass % of tannic acid, and between about 0 and 30 mass % of a silane coupling agent, and wherein the bonding undercoat is essentially free of chromate.