Zhejiang maker scales up deep-sea buoyancy foam

A Christmas-lights exporter spent a decade learning how to make foam survive the deepest parts of the ocean. Taizhou Zhongfu New Materials, founded by Qu Longkui in Zhejiang, has now reached full mass production around 2022, after investing more than 200 million yuan in a material the company says was long dominated by Western suppliers.

The product is wrapped around subsea cables, underwater equipment and submersibles. It provides buoyancy without collapsing under pressure, reducing weight, tension and long-term wear. Zhongfu rates its deep-sea grade for 11,000 meters and 150 megapascals—1,500 times standard atmospheric pressure. With a density half that of seawater, each ton of finished foam produces one ton of effective net buoyancy, enough to hold a fully loaded SUV afloat.

The technology has a growing job description. It supports floating offshore wind, including a major commercial project off Wanning in Hainan where turbines weigh thousands of tons and subsea cables run more than 20 kilometers. The same material is used for offshore oil and gas platforms, underwater robots and deep-sea scientific exploration.

Getting there was not smooth. Early production brought unstable quality and poor yields. A trade-secret accusation in the United States, begun around 2017 and dropped after seven years, cost the company time and talent. A domestic oil and gas company became a partner in 2017, demanding performance benchmarked against international leaders. After years of iteration, Zhongfu says its product passed acceptance with some metrics exceeding imported alternatives.

So what changes in practice? Zhongfu’s new Taizhou base has annual capacity of 10,000 cubic meters, while Zhongfu says its material costs more than 30% less than imports. Delivery falls from nine to twelve months to three to four months. For deep-sea projects whose daily construction costs run into hundreds of thousands of yuan, that shorter wait can remove a major scheduling constraint. The company expects production value to reach 500 million yuan within three years, while Qu continues to run the Christmas-lights business that financed the effort.