(Source: Cetie)


Neck Finish

Cetie issues a new free standard for PET neck finish dedicated to attached caps

Josquin Peyceré, Secretary General of Cetie, Paris, France

In the context of European Directive 2019/904, the European Commission mandated the CEN (European Committee for Standardisation) to draft a standard to establish the specifications for attached caps of single use plastic bottles.

After many meetings in CEN, with intensive support of Cetie*, the first project for the standard has now been written and registered at CEN at the end of 2020. The specifications are based on two key requirements:

  • The attachment of the cap with the PET-bottle must resist a minimal force of 25 Newtons (12N for some other types of containers).
  • The attachment must withstand 10 opening/closing cycles without breaking, so as to be reliable throughout repeated openings of the product.

In order to respect the application period required by the European Commission (July 2024) and to anticipate the modifications required to products and production lines, manufacturers in the sector are already introducing attached cap solutions.

To avoid a situation in which each industry player creates its own specific finish, Cetie members immediately saw the need to create a standardised PET finish, adapted to highly carbonated beverages with up to 10g/l CO2 (5.2 Vol% CO2 ) and volumes of up to 3 litres. Developed within Cetie’s PET-Plenary group, and championed by The CocaCola Company, this finish has its weight reduced to a minimum, which required tests to be performed on the various technical options in coordination with cap suppliers, preform manufacturers, and soda brands, until the best compromise was ultimately identified: a 15.06 mm high finish, with a thread diameter of 26.44 (24.20 mm diameter at thread root), and a unique thread that runs almost two turns on a pitch of 2.30 mm. This finish, named GME30.40, allows for a space above and below the Pilfer Proof ring for the tamper-evident band and for the cap tethering system. It can be fitted for various diameters of support ledges, from 29 to 33 mm according to the type of bottles, and weighs 2.70 g in its widest version (33 mm) and 2.53 grams in its smaller version (29 mm). Flash the QR-code to access to the latest version of the drawing, not yet industrially validated, which means that small adjustments might still be needed.

Note that a derivative version responds to demand from countries outside of the European Union. This version, named GME30.41, and dedicated to caps without attachment feature, has the same general characteristics, but with a height of only about 13.40 mm, and consequently a lower weight.

So, while the European Directive had requested caps to be attached by 2024, as early as 2021 a technically validated high-performance finish will be standardised within Cetie.



* Cetie –International Technical Centre for Bottling and related Packaging – is an international association publishing technical reference documentation on bottling and related subjects.