Hollow body such as a golf-club head, made of molded thermoplastic material comprising an imprisoned insert, and method for the manufacture thereof

A method of producing a hollow body with an insert therein occupying less than the entire hollow volume of the hollow body, the method comprising:

• placing an insert having a first part with an external shape which is shaped to define part of the final shape of the interior of the hollow body to be molded and having a second part which is to be facing into the hollow of the hollow body after it is molded;
• overmolding a core of fusible material over the second part of the insert, so that the core has a third part which is on the second part of the insert and has a fourth part with an external shape which is also shaped to define another part of the final shape of the interior of the hollow body, and so that the insert and the core of fusible soft material together define an assembly for being further overmolded;
• overmolding over the first part of the insert and the fourth part of the core a cover of a material which is adapted not to melt when the core of fusible material melts for forming the overmolded body over the insert and the core;
• melting the fusible material of the core without melting the material of the cover and removing the melted fusible material from inside the body while the insert remains inside the body producing a hollow space in the body.