Solvay has secured a key legal victory after the European Patent Office upheld its patent EP ’138, rejecting an opposition filed by WE Soda Ltd and confirming the patent’s validity with only limited amendments. 

 

The decision follows oral hearings held on May 19, 2026, and stems from proceedings initiated on February 13, 2025. An appeal remains possible.

 

The upheld patent, granted in May 2024, protects Solvay’s proprietary method for treating and recycling purge streams generated in the production of sodium carbonate (soda ash) and sodium bicarbonate. It also covers the related manufacturing process and the end products derived from it.

 

The ruling strengthens Solvay’s wider intellectual property position in a sector where process innovation is central to industrial competitiveness. EP ’138 sits within a broader patent family that includes EP 2 878 579 B1 (“EP ’579”), which is already the subject of separate litigation between the two companies.

 

That parallel dispute has been unfolding in the Netherlands since August 2021, where Solvay accused WE Soda and affiliated entities—including Turkish subsidiaries linked to its Kazan Soda operations—of infringing EP ’579. 

 

In December 2025, a Dutch court ruled in Solvay’s favor, upholding the patent and ordering an injunction preventing the import and supply of infringing products in the Netherlands. WE Soda and related parties have appealed that ruling, with proceedings ongoing.

 

Because EP ’138 is a unitary patent, enforcement options could extend across multiple European jurisdictions through the Unified Patent Court system, enabling broad, multi-country injunctions in a single action.

 

Solvay says the outcome reinforces the importance of intellectual property protection in maintaining fair competition and confirms its intent to continue aggressively defending its innovations worldwide.