March 18 (Reuters) - Dow Chemical Co said it plans to build several plants on the U.S. Gulf Coast to take advantage of cheap shale-derived natural gas to produce plastics used in areas such as transportation and telecommunications.

The U.S. plastics-producing industry is increasingly shifting away from oil-derived naphtha, the key feedstock for the petrochemical industry. It is also investing billions in plants that run on ethane, made from shale gas.

Over the past few years, Dow has changed its focus from low-margin commodity chemicals to high-margin specialty materials. The biggest U.S. chemical maker said last week that it planned to raise $1.5 billion from asset sales over the next 18 months to focus on high-margin businesses.