(Adds detail, background)
By Arno Schuetze
FRANKFURT, March 21 (Reuters) - Italian engineering group Coesia and German industrial holding Koerber are preparing offers for Bosch's ROBG.UL packaging machinery business, people close to the matter said.
German car parts maker Bosch put the business on the block earlier this year as part of a portfolio overhaul which will see it emphasise electric and autonomous car technologies.
The Bosch business, which competes with Italy's IMA IMAI.MI , makes machines for pharmaceuticals and food packaging, employs 6,100 staff and has revenues of about 1.3 billion euros ($1.5 billion).
The car industry and its suppliers have come under pressure to accelerate investment in electric and self-driving vehicle technologies, following a regulatory crackdown on diesel.
Private equity firms Triton, Bain, KKR, Cinven and Onex are also expected to make first bids by a mid-April deadline for the business, which the sources say could fetch a valuation of 500-600 million euros, including debt.
The unit is expected to post earnings before interest, tax, depreciation and amortization (EBITDA) of around 40 million euros this year.
Bosch and Koerber declined to comment, while Coesia was not immediately available for comment. The other bidders also declined to comment or had no immediate comment.
Bidders were given access to management after a pre-qualification round, with more in-depth information on the packaging business to follow in April and final bids due in late May or June, the sources said.
STABLE CASH FLOWS
The packaging industry has seen a wave of consolidation in recent years with private equity groups being drawn to the stable cash flows of the firms, which tend to grow in line with GDP, and who have so far seen limited impact from the debate about plastic pollution in the world's oceans.
In a sign that consolidation continues, an auction of a maker of paper packaging is also underway.
Buyout group Aurelius has put Solidus, a producer of solid board and graphic board with facilities in the Netherlands, Belgium and Britain on the block in a potential 400 million euro deal, people familiar with that deal said.
Several private equity groups are preparing first-round bids, due March 27, for the company with an expected EBITDA of 40 million euros.
Aurelius and its adviser Rothschild declined to comment. ($1 = 0.8782 euros)