The Calcutta High Court has granted an interim injunction restraining Finorchem from using NOCIL’s patented process for manufacturing 4-Aminodiphenylamine (4-ADPA), a key rubber anti-oxidant intermediate. The Court applied the ‘clear the way’ doctrine, holding that Finorchem’s failure to challenge NOCIL’s three long-worked, commercially exploited process patents, by way of pre-grant opposition, post-grant opposition, declaration suit, restoration or revocation, before launching its own 4-ADPA plant weighed heavily against it.
The High Court applied the ‘pith and marrow’ test to hold that Finorchem’s repeated process amendments, including deletion of the aniline-to-nitrobenzene molar ratio and labelling the second hydrogenation step as ‘optional’, were a calculated attempt to evade infringement. Strikingly similar EIRA Reports and inconsistent process disclosures further dented Finorchem’s credibility. On confidentiality, the Court held that the NDA specifically referring to 4-ADPA bound the ex-employee regardless of his role description, and that Finorchem’s recruitment of the said ex-employee constituted surreptitious procurement of trade secrets.
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Briefly, NOCIL Limited, one of the largest manufacturers of rubber chemicals in India, filed a suit for patent infringement and breach of confidentiality against Finorchem Limited (Respondent No. 1) and its former employee (Respondent No. 2). NOCIL had developed a novel process for manufacturing 4-Aminodiphenylamine (4-ADPA), a chemical used as an anti-oxidant for rubber and polymer applications, and secured three Indian patents in respect of the said process, Patent No. 341922 (granted on 17 July 2020), Patent No. 366559, and Patent No. 389262, along with equivalent US registrations.
Respondent No. 2, a B.Sc. graduate, had joined NOCIL in 1987 as a Production Supervisor and retired on 30 September 2020 as DGM-Process Technology. He was involved in the development and implementation of the 4-ADPA processes at NOCIL’s Dahej plant and had executed a Non-Disclosure Agreement (NDA) dated 11 May 2012 specifically referring to 4-ADPA.
The grievance arose when NOCIL came across an Environmental Impact and Risk Assessment (EIRA) Report filed by Respondent No. 1 in relation to its proposed 4-ADPA plant, which prima facie appeared strikingly similar to NOCIL’s own EIRA Report. Upon enquiry, it transpired that Respondent No. 2 had been engaged by Respondent No. 1 after his retirement for the manufacture of 4-ADPA. Respondent No. 1 thereafter filed a process patent application for 4-ADPA on 19 April 2024, was directed by court order dated 26 November 2025 to disclose its process, and subsequently applied for amendment of its patent application on 6 February 2026.
A Single Judge Bench of Justice Ravi Krishan Kapur observed that registration of a patent is not prima facie evidence of its validity, as evident from a conjoint reading of Sections 12 and 13(4) of the Patents Act, 1970, marking a deviation from the Trade Marks Act, 1999. Nevertheless, at the prima facie stage, the grant of a patent after a rigorous process of examination deserves recognition and should not be outrightly disregarded.
Under Section 107 of the Act, a defendant is entitled to raise every ground on which a patent is vulnerable to revocation under Section 64 as a ground of defence. At the prima facie stage, a defendant is not required to make out a full case of vulnerability, all that is required is to raise a credible challenge, one which is not fanciful, illusory or moonshine but is prima facie acceptable, added the Court.
The Court noted that the suit patents are old, established and working patents, granted after extensive examination in India and other jurisdictions, and have been commercially exploited without interruption for over a decade. Due weightage must therefore be given to the grant of these patents. A striking similarity was observed between the EIRA Reports of NOCIL and Respondent No. 1, with the Court finding them virtually identical. The Court rejected the explanation that the report was prepared by the same agency, holding that unless the process used by Respondent No. 1 was identical to that of NOCIL, there could be no reason for such verbatim reproduction.
The Court applied the ‘clear the way’ doctrine, observing that a would-be entrant seeking to launch a process which may be covered by an existing patent must take steps to remove all obstacles before commencing its activities rather than waiting to be sued. Respondent No. 1 had failed to avail any statutory remedy, whether by filing a pre-grant opposition under Section 25(1), post-grant opposition under Section 25(2), a suit for declaration under Section 105, restoration under Section 106, or a revocation application under Section 64, prior to the filing of the suit.
The Court found that Respondent No. 1 had taken at least three different and inconsistent positions regarding its process. The drastic amendments sought by Respondent No. 1 were held to be nothing more than an attempt to evade liability for infringement, with the proposed deletion of the molar ratio range and the labelling of the second hydrogenation step as ‘optional’ being specifically noted as calculated attempts to disguise the real process being used.
An analysis of the two processes revealed a number of common steps (Steps A to L) covering the entire chain from reacting aniline with TMAH through to the conversion of 4-ADPA to 6-PPD. The differences attempted by Respondent No. 1 were held to be minor and inconsequential variations. The Court found that the conduct of the respondents prior to and subsequent to the filing of the suit was clandestine, secretive, and not with clean hands. The belated challenge to the invalidity of the suit patents, the failure to contemporaneously disclose the relationship between Respondent Nos. 1 and 2, and the filing of an identical patent application 15 months after the suit were all noted as factors demonstrating dishonest conduct.
On the breach of confidentiality, the Court observed that the NDA clearly records that Respondent No. 2 was working on a project involving ‘unique steps and methods to be tried at the laboratory and pilot plan before commercialization’, and that all such information was the subject matter of secrecy and confidentiality. The contention that Respondent No. 2 was not a technical person was held to be falsified by his own qualifications and the plain reading of the NDA. The Court rejected the contention that the questions of breach of confidentiality and infringement are mutually destructive, observing that information can retain the quality of confidence even though some of its constituent elements are themselves available in the public domain.
