PETpla.net Insider 07+08 / 2015

CAPPING CLOSURES 31 PET planet insider Vol. 16 No. 07+08/15 www.petpla.net Different applications, neck finishes for various, part 2 Closure for PET bottles PETplanet Insider is publishing extracts from successive chapters of Ottmar Brandau’s “Bottle, Preforms, Closures”, which was published by hbmedia. A newly revised version is reissued under the Elsevier imprint. Bottle neck finish and closure must be a match, and designers on both sides have come up with a series of standards, mostly voluntary industry standards, to make sure that caps perform their function well. For the end user it is paramount to under- stand the required functionality of the package, then select the appropri- ate neck finish, and finally choose between the different closure solu- tions for this finish. This chapter will list the most common neck finish/ closure solutions under common func- tional considerations. 4.2.1 Neck finishes for CSD bottles The most important feature of this package is to retain the carbonation level in the drink. Pressure inside the bottle can go as high as 5 bar (70 psi), and closure seals are constructed in such a way that increased pres- sure improves the seal rather than weakens it. All CSD neck finishes feature two full thread turns assuring Fig. 4.2