If the defects such as swelling and peeling occur to the formed coating film (damping material), the damping performance of the damping material is impaired, and in the case where a worker touches the damping material, or the damping material is subjected to contact, shock, or the like when another part is attached to the damping material, breakage or peeling of the damping material is liable to occur. Patent Literature 4 discloses an aqueous resin composition to be used for imparting damping properties, the aqueous resin composition containing at least: a polymer synthetic resin emulsion and a hollow particle made of a resin having a glass transition temperature (Tg) of 40 to 140° C.Ī damping material using a conventional resin emulsion, when applied and dried to form a coating film, is liable to cause coating film defects such as swelling and peeling to occur. Patent Literature 3 discloses an aqueous damping paint composition containing a resin emulsion as a main component, wherein a fusion bond retardant that retards fusion among the resin emulsions during drying is blended. Patent Literature 2 discloses an aqueous damping material containing an aqueous resin emulsion, a predetermined heat-curable resin, and a heat-foaming agent each in a predetermined ratio.
Patent Literature 1 discloses an aqueous damping paint being a baking type aqueous paint using a resin emulsion, the aqueous damping paint containing 0.1% by mass or more and less than 5% by mass of a heat expansion type organic hollow filler or organic foaming agent. Among the damping paints, a damping paint using an aqueous resin emulsion has advantages that a working environment in forming a coating film (damping material) is favorable and that environmental load is small, and therefore various proposals have so far been made (see, for example, Patent Literatures 1 to 4). On the other hand, the damping paint is easily utilized irrespective of the shape of the position where the damping material is to be provided because the damping material can be formed by means of a coating film through coating, and automation by means of robot coating can be performed, so that it can be said that the damping paint is advantageous in terms of productivity, workability, and the like.
In the case of the sheet-like damping material, a worker needs to cut the sheet-like damping material so as to match the shape of the position where the sheet-like damping material is to be provided and then install the sheet-like damping material. As the damping material, a sheet-like damping material containing asphalt as a main component, and a damping material (damping paint) in the form of a paint are used. A damping material is provided in a vehicle floor and of automobiles, and the like in order to prevent vibration.