* Initial bids for Hitachi Chemical Co due by Aug. 9
* Deal seen attracting private-equity interest
* Japanese firms also seen bidding (Adds details and context)
By Junko Fujita and Taro Fuse
TOKYO, July 11 (Reuters) - Japan's Hitachi Ltd has started the formal process for the sale of its $5.6 billion chemical unit with initial bids due in August, people familiar with the matter said, a deal that is expected to draw interest from global private-equity firms.
Hitachi has asked potential bidders to submit first-round bids for Hitachi Chemical Co, four people said, declining to be identified as the information is not public.
The initial round will close on Aug. 9, two of them said.
Hitachi has hired Bank of America Merrill Lynch while Hitachi Chemical has retained Goldman Sachs Group Inc to advise on the deal, the two people said.
Reuters reported in May that global private equity firms Bain Capital, Carlyle Group and KKR & Co are among the bidders for the unit, of which Hitachi owns 51.2 percent.
Japanese companies are also expected to submit initial bids along with the three private-equity firms, the two people said.
A Hitachi spokesman declined to comment.
A spokeswoman for Hitachi Chemical said the company has not made any announcement on the issue. Goldman Sachs and Bank of America Merrill Lynch also declined to comment.
The sale would be the largest corporate spin-off in Japan this year. Hitachi and other local firms are under pressure to focus on areas with growth potential and hike shareholder value.
Hitachi is rare among big Japanese corporations for the active reorganisation of its businesses. It has sold off semiconductor equipment maker Hitachi Kokusai Electric and power tool unit Hitachi Koki, both to KKR. It also sold car navigation maker Clarion Co to France's Faurecia SA.
Doing so has reduced its so-called parent and child listings, the Japanese corporate tradition where large listed firms own big stakes of smaller, listed affiliates. Global investors have long called for those stakes to be sold down. ($1 = 108.8900 yen) (Reporting by Junko Fujita and Taro Fuse; Editing by David Dolan and Himani Sarkar)