Part for connecting a fluid line to an opening of a container comprising plastic material or for closing the opening

A tubular part for connecting a fluid line to an opening of a container comprising HDPE (high-density polyethylene), the part comprising:

• a first component and a second component each comprised of primarily thermoplastic material;
• wherein the first component has a surface to be connected to the container;
• wherein the material of the first component is configured to form with the HDPE of the container a heat fusion joint via the surface by welding but has no sufficient diffusion barrier capability relative to hydrocarbon fuel;
• wherein the material of the second component, in comparison to the material of the first component, has a significantly higher diffusion barrier capability, a reduced swelling capability relative hydrocarbon fuel, a higher mechanical strength, even after hydrocarbon fuel exposure, and a higher thermal shape stability;
• wherein the tubular part is formed as one piece via injection molding.
• wherein the material of the first component surrounds the second component up to an injection location positioned at an end face of the tubular part, said end face being at the end of the tubular part adapted to receive the fluid line;
• wherein the material of the second component has been injected into the core of the material of the first component via the injection location.