Scientists at RIKEN in Japan have developed a new type of plastic that’s just as stable in everyday use “as the regular stuff” but dissolves quickly in saltwater, leaving behind safe compounds.

It takes decades before plastic fully breaks down. And when it does, it forms microplastic pieces that are turning up in all corners of the natural world, including our own bodies, where they wreak havoc on our health.

RIKEN researchers have developed a new type of plastic that can work just as well as the regular stuff but breaks down readily into safe compounds. It’s made of supramolecular polymers, which have reversible bonds that can be attached, removed and reattached.

Researchers identified sodium hexametaphosphate, a common food additive, and monomers which are used in fertilizers. When these two compounds are mixed together in water, they form a viscous material that can be dried to form plastics.

The material is as strong as normal plastic, and is non-flammable, colorless and transparent. Immersed in saltwater though, the plastic completely dissolved in about eight and a half hours.

The team found that applying hydrophobic coatings prevented any early breaking down of the material. The material breaks down into nitrogen and phosphorus, which are useful nutrients for plants and microbes.