Process for producing hollow resin-molded article, and fuel tank

A process of producing a hollow resin-molded article using a mold comprising a pair of mold halves, the method comprising steps of:

• arranging a cover on an inner wall of each of the pair of mold halves, the cover being premolded and having a shape corresponding to the inner wall;
• introducing a thermoplastic resin fusion-weldable to the cover into an inner space between the pair of mold halves so as to form a pair of sheets of thermoplastic resin each facing the cover arranged on the inner wall of corresponding one of the pair of mold halves;
• blowing air into an intermediate space between the pair of sheets of thermoplastic resin to cause each of the pair of sheets of thermoplastic resin to contact the cover arranged on the inner wall of corresponding one of the pair of mold halves, and thereby fusion-welding each of the pair of sheets of thermoplastic resin to the cover arranged on the inner wall of corresponding one of the pair of mold halves;
• closing the pair of mold halves;
• and
• cooling down the covers and the pair of sheets of thermoplastic resin in a state where the pair of mold halves is closed,
• wherein the covers and the pair of mold halves are configured such that, in the step of arranging the cover, there is an uncovered portion of the inner wall of each of the pair of mold halves that is not covered by the corresponding cover, and that, in the step of closing the pair of mold halves, there is a mold contact portion of each of the pair of sheets of thermoplastic resin that directly contacts the uncovered portion of the inner wall of corresponding one of the pair of mold halves and the mold contact portions of the pair of sheets of thermoplastic resin are fusion-welded to each other in an overlapping manner.