Patent ID: 7828334

Claim:
A joint part for a resin fuel tank, the joint part having an approximate cylindrical shape and a welding portion at its distal end to be positioned and welded to a rim of an opening end of the resin fuel tank, wherein at least the welding portion comprises an approximate cylindrical barrier layer formed by the following (A) and an approximate cylindrical welding layer formed by the following (B) on at least one surface of an inner periphery and an outer periphery of the barrier layer; wherein (A) is a compound material obtained by blending polyethylene into at least one selected from the group consisting of an ethylene vinyl alcohol copolymer, polyamide, polyester and liquid crystal polymer; (B) is a high density polyethylene or a modified high density polyethylene; and wherein when (A) and (B) are kneaded with high shearing, (A) forms a matrix, (B) forms a domain, and an island phase of (B) is dispersed in a sea phase of (A).