US Patent 7466839 Waterproof vibration plate for speaker

There is provided a speaker that uses a waterproof vibration plate that is obtained by forming a water repellent layer containing wax on a surface of paper pulp by the use of a wax-based emulsion in a suspension of the paper pulp, then forming a binder layer containing rosin or alkyl ketene dimmer on a surface of the water repellent layer by the use of a rosin sizing agent or an alkyl ketene dimmer sizing agent in the suspension, then forming an oil repellent layer containing a fluorinated resin on a surface of the binder layer by the use of a fluorine-based resin emulsion in the suspension, then forming the paper pulp into paper, and then heating and drying the same.