Closure cap made of plastic

A closure cap made of a plastics material, for closing a container comprising polyethylene terephthalate (PET), the closure cap comprising:

• a circular head plate,
• a cylindrical threaded part surrounding the circular head plate, the cylindrical threaded part comprising an open edge and an inner thread, and
• a sealing cone protruding on an inner side of the head plate, wherein
• a connection ring interposed between the sealing cone and the circular head plate, the connection ring having a wall thickness of between 0.2 and 0.4 mm and operatively couples the sealing cone to the circular head plate and
• the closure cap, together with the sealing cone and the connection ring, is made of PET.

In combination:

• a closure cap made of a plastics material, for closing a container comprising polyethylene terephthalate (PET), the closure cap comprising:
• a circular head plate,
• a cylindrical threaded part surrounding the circular head plate, the cylindrical threaded part comprising an open edge and an inner thread, and
• a sealing cone protruding on an inner side of the head plate, wherein
• a connection ring interposed between the sealing cone and the circular head plate, the connection ring having a wall thickness of between 0.2 and 0.4 mm and operatively couples the sealing cone to the circular head plate and
• the closure cap, together with the sealing cone and the connection ring, is made of PET, and
• a container made of PET comprising a container neck having an outer thread onto which the closure cap is selectively screwed on and off,
• wherein the outer thread has a surface roughness of between 0.1 μm and 0.2 μm.

A method for making a closure cap in an injection mold comprising a die and an injection core, the closure cap being made of a plastics material, for closing a container comprising polyethylene terephthalate (PET), the closure cap comprising:

• a circular head plate,
• a cylindrical threaded part surrounding the circular head plate, the cylindrical threaded part comprising an open edge and an inner thread, and
• a sealing cone protruding on an inner side of the head plate, wherein
• a connection ring interposed between the sealing cone and the circular head plate, the connection ring having a wall thickness of between 0.2 and 0.4 mm and operatively couples the sealing cone to the circular head plate and
• the closure cap, together with the sealing cone and the connection ring, is made of PET,
• the method comprising heating the injection mold during injection molding of molten PET to a temperature of between 12 and 52° C.