UPDATE 1-China's aluminum foil makers plan challenge to U.S dumping duties -sources

-sources@ (Updating to add details throughout)

BEIJING, Aug 9 (Reuters) - China's top aluminum foil producers are preparing to launch a legal defense challenging a preliminary U.S. ruling on Wednesday to impose hefty penalties on imports from the world's top producers, two sources familiar with the matter said.

Loften Aluminum, China's top foil exporter to the United States, is joining 11 other companies to fight the ruling, the first such case since the inauguration of U.S. President Donald Trump, an official at the company said, speaking on condition of anonymity.

The China Nonferrous Metals Industry Association (CNIA) is leading the charge on the case, an official at the body said.

The companies plan to file their case later this month, the Loften official said. If the duties are implemented, Loften would face anti-subsidy duties on its foil sales to the United States of 80.97 percent.

Among the companies involved in the plan are Dingsheng Aluminum Group, Xiashun Holdings Ltd and Jiangsu Zhongji Lamination Materials Co Ltd.

The U.S. ruling came five months after the domestic foil industry filed a petition accusing Chinese manufacturers of dumping the product in the United States.

The Chinese challenge will likely heighten tension between the world's two largest economies as Washington threatens further action against China's steel and aluminum sectors.

China produces over half the world's aluminum and exported 1.1 million tonnes of foil last year, up 13 percent from 2015 and more than double levels at the turn of the decade.

(Reporting by Tom Daly and Beijing newsroom; writing by Josephine Mason; editing by Jason Neely and David Evans)