VanDeMark Chemicals has been acquired by a pair of New York City private-equity firms in a deal that will keep the top management at the Lockport chemical company.

The private-equity firms, Brightwood Capital Advisors and Uni-World Capital, purchased VanDeMark from Buckingham Capital Partners, a New York City leveraged buyout firm that had purchased the former Isochem Inc. five years ago from a French company, Groupe SMPE.

The terms of the deal were not disclosed, but Buckingham said it earned a 30 percent internal rate of return on its investment in VanDeMark. Buckingham said VanDeMark’s earnings more than tripled to a record high during the time it owned the company.

The new owners, who completed the acquisition at the end of November, said VanDeMark’s three top managers — CEO Mike Kucharski, Chief Operating Officer Paul Ameis and Bob Bigos, its chief financial officer — are remaining in their positions and continue to hold a “significant” ownership stake in the business.

Kucharski said the new owners are hoping to launch an expansion program that would broaden VanDeMark’s operations and its markets.

“Since our spin-off from SNPE in 2007, we have been readying the company’s operations and facilities for expansion,” Kucharski said. “We now have the ownership and financial resources to take the next step in that growth plan.”

VanDeMark has about 85 employees at its plant on North Transit Road, which is about 10 percent less than it had five years ago. The company makes phosgene, phosgene derivatives and other chemicals that are used by its customers to make a wide range of products, from paint and pharmaceuticals to polymers and sealants.

“VanDeMark is a great company with a blue-chip customer base and significant potential in both existing markets and as yet undeveloped end uses,” said Sengal Selassie, Brightwood Captital’s co-founder, in a statement.

In a bid to reduce its capital costs and simplify its ownership structure, Buckingham recapitalized VanDeMark late last year through a $34 million refinancing that included $31 million in debt from Prospect Capital, a closed-end investment company in New York City, and additional financing from First Niagara Bank.