Tube head with insert forming a barrier

An assembly comprising:

• a tube head comprising:
• a body, formed from a plastics material, comprising a neck having an opening at a first end, through which opening a product is removed from the internal volume of the tube, and a shoulder which is joined to a second end of the neck opposite the first end;
• an insert arranged so as to be in contact with said shoulder so as to form a barrier between the body and the product contained in the internal volume, said insert comprising a central portion and a peripheral region, said central portion forming a non-perforated disc sealing the neck, and said peripheral region being mounted so as to be in contact with a complementary planar surface of the body, the insert being substantially planar and within a cylindrical volume of diameter D and height h, a ratio of the value h/D being less than 0.1;
• and
• a flexible skirt associated with said tube head so as to form an internal volume of the tube, said internal volume being separated from the neck by the insert.