If it goes ahead, the deal would add the world's leading maker of sealants for beverage, food and aerosol cans to Henkel's adhesives division, which accounts for about half of group revenues at the maker of laundry detergent Persil, beauty line Schwarzkopf and Loctite glue.
Analysts said on Thursday the price, which is on a debt and cash free basis, looked expensive at first glance, valuing Darex at around 3.5 times annual revenues or around 14 times operating profit.
"However, we need more information with regards to profitability and growth potential of this seemingly very attractive business to fully judge the acquisition price," Baader Helvea analyst Christian Weiz said.
Kepler Cheuvreux analyst Christian Faitz said assuming 10 percent of synergies on sales, the offer valued Darex closer to 10 times operating profit.
Henkel has said acquisitions would remain a key part of its strategy after it spent $3.6 billion to buy North American detergent maker Sun Products, known for its Snuggle brand.
U.S.-based GCP said a sale of Darex would allow it to focus on its construction and building materials businesses. It will now begin consultations with workers' representatives and then enter into a definitive agreement with Henkel.
Goldman Sachs is advising GCP on the deal. Wachtell, Lipton, Rosen & Katz is the legal adviser and EY its transaction advisor, GCP said.
Reporting by Maria Sheahan; Editing by Amrutha Gayathri and Alexander Smith