Rome banned Chinese silk to stop its gold from flowing east
Roman glass was a luxury in China.

TED-Ed · The Silk Road: Connecting the ancient world through trade - Shannon Harris CasteloRome banned Chinese silk.
In the second century BCE, after Chinese ambassador Zhang Qian came back to the Han Emperor describing advanced societies and foreign goods beyond China's western borders, China sent ambassadors and merchants toward Persia and India, exchanging silk and jade in return for horses and cotton, with armies sent for protection.
Routes in the east and west had joined into a connected network stretching across Eurasia. Chinese goods reaching Rome drained gold away and prompted the ban.
Glass from Rome was greatly valued in China.
Questions people ask
What was different about Roman glass?
Roman workshops blew glass into thin cups, bottles and bowls. Thin, clear vessels were rare and hard to make. That made Roman vessels an unusual import in China.
Did any merchant travel all the way from China to Rome?
Rarely, if ever. Goods were handed from one group of merchants to the next along linked routes through Central Asia. That relay let goods travel farther than any single merchant.
Was the Silk Road a single road?
No. The name covers many routes that joined over centuries across Eurasia. Eastern and western sections linked together until goods could move from China to the Mediterranean.