Stormking, a supplier of moulded GRP building components to the house building and construction industry, was founded in 1985 by Gary King and Barry Whitehall.
The duo recently retired after 30 years of running the firm, having handed over day to day management to a new management team, who will now take the business forward as part of Epwin Group.
In a joint statement, King and Whitehall said: "The decision to finally bring to a close our involvement in Stormking Plastics was never going to be easy.
"But in Epwin Group we are confident we have found a group that will allow Stormking Plastics to broaden its offering and continue to see the brand and reputation enhanced.
“We look forward to watching with interest and to learning of the continued success of Stormking."
Jon Bednall, chief executive officer of Epwin Group, added: "I am delighted to announce the acquisition of Stormking Plastics and extend a warm welcome to the group to the team there.
“Stormking adds further to the group's range of low maintenance building products as well as the plastics materials technologies that we can draw upon.
“The acquisition represents a further significant step in the development of the group and is expected to enhance earnings in 2016."
In the financial year ended 28 Feb 2015, Stormking reported turnover of £22.8m and underlying EBITDA of £3.0m.
In the current year to February 2016, performance is expected to deliver turnover in the order of £25m and an underlying EBITDA, of circa £4.5m.