FRANKFURT (Reuters) - Thailand's PTT Global Chemical has agreed to buy German coating resins maker Allnex from buyout group Advent in a 4 billion euro (US$4.75 billion) deal, one of the largest acquisitions by a Thai company in recent years.

       PTT Global Chemical said it agreed a loan agreement with its parent, PTT, an energy major, for up to 73.9 billion baht (US$2.27 billion) to fund its investment.

       Shares in PTT Global Chemical ended 6.5% lower, the biggest fall since April 2020 as investors fretted about the price.

       "We see this as a major diversification into the coatings business, which is less cyclical than commodity chems. Valuation seems slightly on the high side", Citi analyst Oscar Yee said in a note.

       The deal values Allnex at 12.2 times its annual core earnings of 325 million euros in the 12 months ended in March 2021.

       Allnex, whose products are used in the industrial metal, automotive and packaging industries, has annual revenue of 2 billion euros and employs 4,000 people worldwide.

       Advent acquired Cytec Industries' coating resins business in 2013 for $1.15 billion euros, rebranded it Allnex and merged it with peer Nuplex in 2016, which it bought for US$800 million.

       Advent sold Allnex to PTT Global Chemical after bilateral discussions and did not run an auction process, said Advent managing partner Ronald Ayles.

       "In the eight years we have invested in Allnex, turnover has doubled and earnings have grown even more. We've gone where the growth is and we're very strong in Asia right now", Ayles added.

       PTT Global Chemical's acquisition of Allnex will improve the latter's access to raw materials and to the Asian market, which has strong growth potential for coating resins, the companies said.

       The deal is expected to close in the fourth quarter.