When China comes up in the presidential debate Monday night, Mitt Romney could be asked to defend the outsourcing of jobs at Sensata Technologies Inc., a Bain Capital investment that has drawn fire over the past week.

Sensata is based in Attleboro, where it employs about 900 people. But 1,100 miles away, in Freeport, Ill., Sensata is shutting down a plant, letting go of 170 workers, and sending that work to China. Workers have been protesting the shutdown and arguing for better severance pay; several people have been arrested.

Sensata’s spokespeople say the employees have known since last year that the plant was going to be shut down. But the closure has turned into political fodder for Romney’s critics, who say this is the legacy of his years in business at Bain in Boston. The Rev. Al Sharpton visited workers protesting at the plant over the weekend. And on Monday, the Rev. Jesse Jackson spoke, and was planning to stay and watch the debate with the workers at an encampment they’re calling “Bainport.”

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“It’s an opportunity for the president to call Romney out on his hypocrisy on China. He still has ties to and is profiting from companies that are outsourcing to China right now,’’ said Zoe Bridges-Curry, a spokeswoman for a coalition of labor and other groups supporting the workers.

Bain bought Sensata in 2006—four years after Romney no longer owned the firm—for $3 billion, from Texas Instruments Inc. Bain still owns about half of Sensata’s stock and occupies seats on the company’s board. Romney, through various investment vehicles, has holdings in Sensata.

Bridges-Curry said the workers have asked Romney to step in and help them, but he has refused. She acknowledged that the Sensata workers “have known for a while” that the plant would shut down two years after Honeywell International Inc. sold it to Sensata.

Romney’s campaign said the Republican nominee is ready to tackle the problems of outsourcing and trade imbalance as soon as he assumes office. “The president has powers no one in the private sector has to level the playing field with China, and President Obama has failed to use them.  As president, Mitt Romney will.” said spokeswoman Michele Davis.

Sensata has 11,400 employees worldwide. It still does some manufacturing in the United States, including in Attleboro, officials said, but its customers are increasingly in Asia. The company said it reaps 75 percent of its revenues there.

“We operate in a competitive marketplace. We often have to change the shape of the company in order to remain competitive,’’ said Jacob Sayer, a spokesman for Sensata. “That often means following our customers into different geographies. It has been going on for decades.”