PETpla.net Insider 09 / 2021

CAPS & CLOSURES 27 PETplanet Insider Vol. 22 No. 09/21 www.petpla.net CAPS & CLOSURES 27  The closure must be compatible with existing preform designs, openings and thread types.  Impact on the end customer should be kept as low as possible, i.e. com- fort of use should not be reduced.  Closures are compatible with exist- ing filling equipment.  Closures are connected to the con- tainer throughout the entire product life cycle until recycling.  Materials for the closures are not changed.  Impact on existing production lines should be minimised and output not reduced.  15 times opening and closing of the cap without loss of function must be guaranteed.  The connection between cap and container must withstand at least 25 N tensile force. Strategies for the production and design of tethered caps Currently, two main production con- cepts exist to achieve the new require- ments for the production of tethered caps:  With the “slit concept”, the cap is cut after injection - this has the advantage that the current tools can continue to be used, but requires an additional work step in production and significantly restricts the design scope of the cap.  With the “bridge concept”, a band is injected along with the cap, which requires new tools. The advantage of this concept, however, is that no additional work step is required after- wards, greater freedom of design is possible for the caps and the injec- tion-moulded connection between the cap and the band can withstand higher loads. Engel sees two variants currently dominating in the design of tethered caps:  The “lasso design” refers to caps that are connected to the bottle with a two-part band. The cap is connected to the upper band and the bottle to the lower band. This design is rela- tively easy to implement with existing tools, usually only the sliders need to be reworked. Do you want high-quality and modern technology for the production of high-class Post Consumer Resin (PCR) and would like to source everything - from sorting to extrusion - from a single supplier? With STADLER you can. +49 7584 9226-0 info@w-stadler.de www.w-stadler.de STADLER Anlagenbau GmbH PLASTIC RECYCLING SYSTEMS: WITH STADLER! OF COURSE Contact us to know more! STADLER: for a clean world!  The “hinge design”, on the other hand, allows the per- manent connection of cap and container by means of a hinge, which optionally also allows the cap to be fixed in a defined position. The use of existing moulds is practi- cally impossible. Impact of tethered caps on production “The new requirements for beverage closures neces- sitate fundamental changes in production,“ explains Jörg Leonhartsberger, Sales Direc- tor Packaging Engel Austria. “Due to the high demand in the market, many manufactur- ers are expected to start with the Lasso solution first as the Hinge design requires high investments in both time as well as financial terms due to the need for a new mould. In addition, the hinge design may require adjustments to the fill- ing line and the feeding of the caps, resulting in further costs.” As a trend for the future, it is expected that in the course of the changeover to tethered caps, many producers will con- sider switching from 1810/1811 cap types to 26mm caps. The advantage here is a possible reduction in cycle time and material usage. For the injection moulding machine, tethered caps require higher injection speeds and increased injection pressure, as the required cavity internal pressure will tend to be higher. The reason for this is the changed filling behaviour with an increased number of filling points on the TE belt. The nec- essary clamping force, on the other hand, will not increase with a change to a 26 mm closure. www.engelglobal.com Engel e-cap