Morgan Stanley's Asia private equity arm is in talks to buy a majority stake in Chinese packaging firm HCP Holdings Inc, four sources with knowledge of the matter told Reuters, a deal that could value the company at about $500 million. The private equity firm aimed to buy about 80 percent of HCP, one of the sources said. UBS AG was advising the fund on the acquisition, and was seeking lenders for a $260 million loan to back the deal, said the sources, who declined to be named because the transaction was private. HCP, Morgan Stanley and UBS declined comment.