The two companies had been in discussions about a merger for some time, and the deal aims to maintain a continuity of supply for all HWCG's customers and suppliers.
PLB has also pledged to take on HWCG's staff.
In a statement, PLB said HWCG's directors put the company into administration because of "financial issues arising from their associated companies in Australia. In contrast to the Australian businesses, HWCG UK has been trading strongly."
It added that the two companies' portfolios were "an extremely good fit".
Managing director Peter Darbyshire said: “Both companies have been very successful despite difficult economic conditions. It is our aim to not just maintain that success, but to build on it strongly.”