Reversing a trend of factories leaving the region, DowDuPont said today that it will invest $45 million to buy a new facility in Newark, Del., to make DuPont Kalrez, a high-temperature sealing material used to make O-rings for electronics, engines, and other hot, high-pressure environments.

The company's DuPont Transportation & Advanced Polymers business plans to replace an existing factory at Tralee Industrial Park, just east of the University of Delaware campus, with a new facility twice as large on Ruthar Drive, near the main hospital operated by Christiana Care Health System, which has succeeded DuPont as Delaware's largest nongovernment employer.

The O-ring plant employs around 200 "skilled operators," and "we expect to need at least this number to operate the new facility," said DuPont spokesman Daniel Turner. The current buildings, put up mostly in 1975 with an addition in 1992, cover about 45,000 square feet, according to county records.

DuPont was "extremely fortunate" to find a local site instead of having to move the business out of state, Randy Stone, president of the polymers business, said in a statement. The plant will be DuPont's main production site for Kalrez, a perfluroelastomer that substitutes for rubber under harsh industrial conditions. The company expects that demand will grow.

The business is part of the Wilmington-based "specialty products" company, one of the three planned successors to be split from the current DowDuPont chemical and materials conglomerate. DuPont says work will transition to the new plant over the next two years.

It's a reversal for DowDuPont's predecessor companies, which sold and closed more factories than they opened in the Philadelphia area in the last 20 years. DuPont consolidated its headquarters to a suburban Wilmington site, closed its former Marshall (South Philadelphia) and Edge Moor (Delaware) plants, and reduced operations at the Experimental Station outside Wilmington and the Chambers Works complex in Salem County as part of the streamlining and spin-offs of some older business lines.

The State of Delaware and New Castle County, where most Delawareans live, had agreed to cut taxes applicable on corporate employers to keep DowDuPont's Specialty Products and Agricultural successors from moving their headquarters out of state.

State and county officials say the company did not ask for and was not given special subsidies for the new plant.