DEDHAM — The company that owns Papa Gino's pizza parlor and D'Angelo sandwich shop chains announced Monday it has closed about 95 locations throughout New England, filed for Chapter 11 bankruptcy protection and reached an agreement to sell the business.

PGHC Holdings Inc.'s announcement came a day after many employees showed up for work to find the restaurants closed without explanation.

The Dedham-based company in a statement said it had reached an "agreement in principle" to sell to Wynnchurch Capital, a private equity firm based in Rosemont, Illinois. Terms of the agreement were not disclosed.

"For some time, we have been pursuing a plan to strengthen our financial footing and secure capital for investment in our restaurants, while also addressing our significant debt load. We are confident that the agreement with Wynnchurch achieves all of those goals," Corey Wendland, chief financial officer, said in the statement.

The restaurants that closed were described as "under-performing." The company said 178 Papa Gino's and D'Angelo locations remain open, including restaurants in North Adams and Pittsfield.

"The company regrets having to close these restaurants but believes focusing resources on a core of best-performing restaurants is the responsible approach," the statement said.

The company said it would try and move affected employees to restaurants still operating.

The proposed sale, which still needs court approval, would strengthen the company's financial resources, allow for the remodeling and modernization of 141 company-owned restaurants in Massachusetts, New Hampshire, Rhode Island, and Connecticut and eventually provide for new locations, the statement said.

Papa Gino's was founded in East Boston in 1961.

D'Angelo Grilled Sandwiches was founded as Ma Riva's Sub Shop in Dedham in 1967.