Patent ID: 11970120
Assignee: INOAC CORPORATION
Field: Other special machines (Mechanical engineering)
Classification: CPC B | IPC B

Claim 6:
7. A method of producing a soundproof member including a polyurethane foam having a first surface layer on at least a part of a first side surface thereof and a second surface layer on at least a part of a second side surface thereof which is opposite to the first side surface, which comprises coating a mold release agent onto a mold surface of a mold, pouring a raw material of polyurethane foam into the mold, and foaming the poured raw material,
wherein the first surface layer and the second surface layer are a layered part on the surface of the polyurethane foam whose density is higher than that of a core of the polyurethane foam,
a mold release agent containing at least linear hydrocarbon wax is coated onto a mold surface forming the first side surface of the polyurethane foam,
a mold release agent containing at least branched chain hydrocarbon wax is coated onto a mold surface forming the second side surface of the polyurethane foam opposite to the first side surface,
the first surface layer in an open cell state is formed on at least a part of the first side surface of the polyurethane foam on the mold surface coated with the mold release agent containing linear hydrocarbon wax, and
the second surface layer in a closed cell state is formed on the second side surface of the polyurethane foam opposite to the first side surface on the mold surface coated with the mold release agent containing branched chain hydrocarbon wax.