The encyclopedia · Engineering & Operations · Technical decision · 2021–2026
SK Chemicals closed the plastic loop by breaking PET back into monomers
SK Chemicals commercialized depolymerization in 2021, turning waste PET back into virgin-quality material — then vertically integrated its feedstock.
SK Chemicals (SK케미칼)
The solution
In 2021 SK Chemicals became the world's first to commercialize circular recycled copolyester made from chemically recycled feedstock; in 2022 it supplied Korea's first circular recycled PET. The process, depolymerization, breaks polyester waste down to its molecular building block r-BHET, then re-polymerizes it.
Unlike mechanical recycling, which turns bottles into lower-value fiber that usually ends up incinerated or landfilled, the depolymerized product has the same properties as oil-based plastic, so a bottle can become a bottle and appliance plastic can return to appliances.
In 2025 SK Chemicals moved to control feedstock: a Recycle Innovation Center at its Ulsan plant and a China joint venture process discarded quilts and PET dust that would otherwise be burned, starting at 16,000 tonnes a year and expected to cut recycled raw-material costs about 20%.
Why it worked
- Monomer-level recycling preserves quality that mechanical recycling loses.
- Closed loops let customers keep using plastic without new oil.
- Owning waste feedstock cuts cost and removes supply uncertainty.
- Hard-to-recycle streams like textiles become cheap raw material.
What can be applied
When the standard process destroys value, pay for the harder one that preserves it — then own the input stream, because the scarce part of recycling is cheap waste, not chemistry.
Aftermath
SK Chemicals' circular-recycling business (Ecozen) became its green growth engine; the Ulsan RIC and Chinese FIC are set to feed SK Shantou's plants, moving the company from recycler to vertically integrated closed-loop supplier for beverage, cosmetics, appliance and auto customers.
Sources
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