BEIJING - Chinese importers of European Union and United States caprolactam will have to put down a security deposit from Tuesday, the Ministry of Commerce (MOC) said Monday.

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A preliminary ruling said caprolactam from the EU and the US had been dumped in China, the ministry said in a statement on its website.

The dumping caused substantial damage to China's domestic industry, the statement said.

A final ruling will be made at a later date after further investigations.

Caprolactam is the precursor to Nylon 6 and is a widely used synthetic polymer.