In 2019, Coca-Cola launched a trial packaging in the Dutch market, with bottles made from ocean-recovered plastic. The media issued press releases, environmental organizations issued statements, and then nothing came of it. The cost of making bottles from ocean plastic is too high, and the volume can't scale up. The recycled plastic bottles actually circulating on the market almost entirely come from land-based recovery systems.
PET stands for polyethylene terephthalate. The name is too long, nobody in the industry calls it that. The bottom of bottles has a mold mark with the number 1, scrap collectors recognize this. RPET is recycled PET. The letter R stands for recycled.
Japan and Germany have mature recovery systems. Japanese convenience stores have collection bins at their entrances, staff regularly collect the flattened empty bottles. Germany relies on deposits-25 cents per bottle. Lidl and Aldi stores all have bottle return machines, you stick it in and it spits out a receipt that you can deduct at checkout.
Recovered bottles aren't clean. Labels, caps, beverage residue, sometimes cigarette butts. The first step at processing plants is crushing-the blades spin very fast, whole bottles go in and fragments come out. Fragments are dumped into water tanks. PET has a density of 1.38, it sinks; bottle caps are polypropylene with a density of 0.9, they float. Scoop away the floating matter and what's left is basically pure PET. Wash once with hot alkaline water to remove glue and grease, spin dry, into the drying room.
Moisture must be reduced to below 50 parts per million. PET degrades when it encounters water in its molten state-industry term is hydrolytic chain scission. If drying isn't thorough, everything after is wasted effort.
Dried fragments enter the extruder screw, heating section temperature between 270 and 280 degrees. The melt passes through filter screens to remove impurity particles, pulled into strands and cut into pellets. This extrusion step inevitably damages molecular chains, intrinsic viscosity drops. Bottle-grade PET requires intrinsic viscosity above 0.8, after extrusion it typically drops to around 0.72. A solid-state polycondensation step must be added afterward-pellets stay in a vacuum drum for over ten hours, temperature maintained below melting point, chain segments re-polymerize, viscosity pulls back up.
The U.S. FDA has a certification process for food contact materials. Manufacturers must submit process documentation proving contaminant removal rates. In the EU it's managed by EFSA, threshold is about the same. Without this certification, the material can only be used for non-food purposes.
Fiber is RPET's biggest outlet. Chips are spun into staple fiber, woven into fleece fabric. Patagonia played the environmental card with this early on, later competitors followed suit, now sports brands more or less all use it. The proportion actually made back into bottles isn't high. Food-grade material supply is tight, sometimes prices are even higher than virgin material.
Recycled plastic has an unavoidable problem: every time it goes through a thermal history the material degrades a bit. Color yellows, acetaldehyde content rises, mechanical properties decline. Bottles recycled into bottles, at most two or three cycles, after that downgraded to fiber, fiber downgraded again to filling cotton or geotextiles, finally still ends up in landfills or incinerators. Closed loop is a talking point. Reality is a slow descent.
