Abstract: Disclosed is a covering member comprising a cylindrical foam or a columnar foam including a cut consisting of a slit line which extends from the outer circumferential surface of the foam to reach a through-hole of the foam, wherein the slit line joining the open portion formed by the cut on the outer circumferential surface of the foam to the open portion formed by the cut on the inner circumferential surface of the foam is nonlinear in respect of the cross section of the covering member in a direction perpendicular to the axial direction of the foam.

Abstract: A method of producing polyurethane foam slab by allowing a urethane foam stock solution in a tank to expand in a reduced pressure. The flatness of the top of the polyurethane foam is secured by providing a lifting jig or a plate within the tank, or by rotating the tank. An apparatus for carrying out the method is also provided.

Abstract: An apparatus for continuously manufacturing polyurethane foam slabs in a batch, which comprises a cylindrical tank for developing polyurethane foam, having an inlet at the side wall thereof for introducing therein polyurethane feed solution; a stirring tank for forming polyurethane foam feed solution, which is mounted on a carriage movably placed in proximity to the cylindrical tank; stirring blades mounted within the stirring tank; a discharge pipe extending from a lower side of the stirring tank to discharge the feed solution through the inlet into the cylindrical tank; pipes for introducing raw materials into the stirring tank; and a pipe for introducing a washing solvent for removing the raw materials. The cylindrical tank is interchangeably connected with the stirring tank through the discharge pipe.