| 摘要 |
PURPOSE:To mold lips correctly and excellently and lower extraordinally the occurrence of defects by fitting an inner mold having a lip molding surface in its outer periphery in the inner surface side of a sealing end for blow boot and pressing in a heat-melted state the outer surface side of a sealing end and then forming lips on the inner peripheral surface of the end for sealing. CONSTITUTION:An inner mold 13 having a lip molding surface 12 in its outer periphery 11 is fitted on the inner surface side of an sealing end 2 of the blow boot 1 molded by a blow molding method. Next, the part of the sealing end 2 is melted by the heating of the order of 70-80 deg.C in accordance with the kind of thermoplastic resin or rubber for forming a blow boot 1. In such a heat- melted state, by the use of outer molds 18, 18 comprising two or more ring- shaped split molds having pressing surfaces in the inner peripheries 17, 17', the side of an outer surface 19 of the sealing end 2 is pressed and thus recessed and protruding seal lip parts 4, 4' are formed on the inner surface side of the sealing end 2. |
