Recycling plastic bottles

Tethered Caps

Misinformation continues to spread about the recyclability of beverage caps. The closures we use on bottles are 100 percent recyclable from a technical standpoint and highly recycled. They are made from high-density materials selected for their compatibility with most recycling systems.

But my question was about whether there is a good reason for the caps and the bottles to be recycled separately. The blurb from Coke you linked says they are processed separately, but recommends putting the tops back on before placing in the bin...contradictory, I think. May sound trivial, but plastic bottles are a big part of polluted waterways and oceans, as well as clogging landfills. So we should try to do it correctly.

There is no simple answer to the question and it depends on what materials were used to make the packaging. The caps are tethered to increase recycling as well as to reduce litter.

The reason for the Coca-Cola tether is the EU directive: "The name of the ordinance isn’t the only thing to pack a punch. The Ordinance on the Labelling of Single-Use Plastics [Einwegkunststoffkennzeichnungsverordnung] implements various sections of the EU directive resolved in 2019, and is a measure that aims to prevent waste. Article 6 (1) focuses on single-use beverage containers and stipulates that after the due date in July 2024, they are only allowed to be placed on the market if their plastic caps and lids remain attached to the bottle during the product’s intended use stage. The ordinance aims to reduce the impact of certain plastic products on the environment and to contribute to the transition to a circular economy."

The Coca-Cola bottle is made from Polyethylene Terephthalate (PET). The Coca-Cola bottle caps are made out of High Density Polyethylene (HDPE); during the recycling process, the caps are detached from the necks of the bottles, collected and used for new products. The Coca-Cola materials have to be processed separately because they are different materials and will cause cross-contamination of the plastic recycle waste streams.

PET Coca-Cola bottles in Germany

Polyethylene terephthalate (PET) and high-density polyethylene (HDPE) are the most important varieties of plastics that are usually used in the manufacturing of drinking water bottles. Depending on their surface characteristics, these particular plastics can be separated from each other by flotation method.

Separation

Other manufacturers than the Coca-Cola suppliers have come up with different solutions and materials for the caps. For example, some are made from PCR plastics. PCR plastics are the recycled materials from existing PET bottles and other plastics.

Other solutions

"Mass production of plastics, which began just six decades ago, has accelerated so rapidly that it has created 8.3 billion metric tons—most of it in disposable products that end up as trash. If that seems like an incomprehensible quantity, it is. Even the scientists who set out to conduct the world’s first tally of how much plastic has been produced, discarded, burned or put in landfills, were horrified by the sheer size of the numbers."

A whopping 91% of plastic isn't recycled

Germany has had regulations on recycling for years. For example, German cars must be manufactured with materials that can be taken apart separated and recycled. All plastic parts are embossed with the name of the plastic material. For other automobile makers, that is not followed unless they sell in Germany.