Manufacturing method of fuel tank welding joint

A method for manufacturing a fuel tank welding joint for connecting a fuel tank to a prescribed member, the method comprising:

• a first step of forming a joint main body made of a first resin material that is configured to be welded to a wall of the fuel tank, the joint main body including (i) a welded edge portion to be thermally welded to the wall of the fuel tank and (ii) a tube portion for connecting a hose, the tube portion having a connecting passage to connect an interior of the fuel tank and the prescribed member;
• and
• a second step of forming a barrier layer by injecting a second resin material into a cavity of a mold unit in which the joint main body has been set, the second resin material being adhesively and chemically reactive with the first resin material and more fuel-impermeable than the first resin material,
• wherein the second step comprises a step of allowing the second resin material to flow through an end of the tube portion into the cavity, so as to form an end portion.

A fuel cut-off valve that opens and closes a connecting passage, which connects a fuel tank to a prescribed member, according to a level of fuel in the fuel tank, the fuel cut-off valve comprising:

• a lid including (i) a lid main body with the connecting passage, (ii) a welded edge portion to be thermally welded to a wall of the fuel tank and (iii) a barrier layer formed on a surface of the lid main body;
• a case main body which is mounted on the lid, the casing main body having a valve chamber connected to the connecting passage;
• and
• a float which is accommodated in the valve chamber, the float rising and falling according to a level of fuel in the fuel tank,
• wherein the lid main body is made of a first resin material that is weldable to a wall of the fuel tank, and
• the barrier layer is made of a second resin material that is adhesively and chemically reactive with the first resin material and that is more fuel-impermeable than the first resin material, the barrier layer having an end portion formed so as to extend past an end of the lid.