Fourteen years of working a patented manufacturing route, followed by a rival\u2019s environmental report that matched the patentee\u2019s almost word for word: that sequence framed a process patent infringement dispute before the Calcutta High Court, decided on 7 October 2026.<\/p>\n
NOCIL Ltd (\u201cNOCIL\u201d), one of India\u2019s largest rubber chemical manufacturers, developed around 2012 a process for making 4-aminodiphenylamine (\u201c4-ADPA\u201d), an anti-oxidant used in rubber and polymer applications. It holds three Indian process patents for 4-ADPA, Nos. 341922, 366559 and 389262, and United States equivalents of two of them. A former NOCIL employee joined in 1987, rose to head operations at the Dahej plant, retired in 2020 as DGM, Process Technology, and had signed a non-disclosure agreement (\u201cNDA\u201d) dated 11 May 2012 that refers specifically to 4-ADPA.<\/p>\n
NOCIL grew concerned when it saw an Environmental Impact and Risk Assessment (\u201cEIRA\u201d) report filed by Finorchem Ltd (\u201cFinorchem\u201d) for a plant proposed to make 4-ADPA, and then learnt that Finorchem had engaged the former employee. Both respondents filed caveats after receiving NOCIL\u2019s notices. On 19 April 2024, Finorchem applied for its own process patent for 4-ADPA. On 26 November 2025, the court directed Finorchem to provide proof of the process it uses, and on 6 February 2026 Finorchem applied to amend its patent application. NOCIL sued for patent infringement and breach of confidentiality, and its interim application, heard on 16 September 2026, was decided on 7 October 2026.<\/p>\n
The court noted that registration is not prima facie proof of validity, because Sections 12 and 13(4) of the Patents Act depart from the trade mark regime, where registration carries that weight. The court further observed that a patent granted after rigorous examination deserves recognition at the prima facie stage. Under Section 107, a defendant may plead every ground of revocation under Section 64, yet the court held that a defendant must still raise a credible challenge, one that is not fanciful or illusory. In this process patent infringement dispute, the court found that old, working patents, exploited without interruption for more than a decade, weighed in NOCIL\u2019s favour.<\/p>\n
The court opined that a would-be entrant planning a process that may be covered by an existing patent must remove the obstacle before starting, rather than wait to be sued. Finorchem had not filed a pre-grant opposition, post-grant opposition, suit for a declaration of non-infringement or revocation application. The court reasoned that this omission weighs at the interim injunction stage in process patent infringement disputes.<\/p>\n
The court found that the EIRA reports of the two companies were virtually identical, and rejected the explanation that one agency prepared both. It held that Finorchem had advanced at least three versions of its process, that the claimed catalyst difference was false, and that the amendments to its patent application, such as replacing a specific molar ratio with a \u201cpredetermined ratio\u201d and labelling the second hydrogenation step optional, were attempts to evade liability.<\/p>\n
The court held that infringement is tested by comparing the patent\u2019s claims with the defendant\u2019s process, looking at the pith and marrow, the essential inventive features, and ignoring trifling variations. It found numerous common steps, and held that specific continuous flow reactors were merely varieties of reactors the patents cover generally. The court stated that, once both processes yield the very same product, the defendant must prove its process differs, and distinguished Natural Remedies Pvt. Ltd. v. Indian Herbs Research & Supply Co. Ltd.<\/em> (2011 SCC OnLine Kar 4561) as a post-trial decision on non-identical products, not authority that validity must be proved first.<\/p>\n The court observed that the NDA is specific to 4-ADPA and records the former employee\u2019s role in developing unique steps, which his qualifications and signed assessment reports confirmed. It found, prima facie, that Finorchem intended to procure a breach. The court also rejected the argument that confidentiality and infringement claims are mutually destructive, reasoning that a patentee need not disclose everything material to the invention and that information can remain confidential though some elements are public.<\/p>\n In view of the observations and the arguments presented by both the parties, the Calcutta High Court held that:<\/p>\nConfidence Survives Alongside a Patent<\/h3>\n
Findings<\/h2>\n
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