The Supreme Industries Ltd. v. Tandhan Polyplast Private Ltd.

When a patent expires, most founders assume the battlefield is over. But what about the moulds, dyes, and manufacturing tools that still carry the DNA of the now-public invention? The interim application between The Supreme Industries Ltd and Tandhan Polyplast Pvt Ltd, heard on 18 December 2023, pulls back the curtain on this exact grey zone, where expired patent rights collide with allegedly infringing material. For any business that relies on proprietary tooling or manufacturing know-how, this case is a wake-up call: the end of a patent does not necessarily mean the end of a dispute.

The dispute pits The Supreme Industries Ltd, the applicant, against Tandhan Polyplast Pvt Ltd, the respondent, in an interim application arising out of a patent infringement controversy. The central question is deceptively simple: are certain moulds and dyes held by the respondent infringing material, even though the original patent underlying the dispute has already expired? This is not a question about whether a patent was validly granted, nor about whether the respondent copied a protected invention during its term. Instead, it sits in the awkward aftermath, where the legal monopoly has ended but the physical instruments of production remain in play. The applicant brought the application seeking relief, and the court was asked to step into a territory that blends technical manufacturing knowledge with legal interpretation.

The applicant, Supreme Industries, argued that the moulds and dyes in the respondent's possession constitute infringing material, regardless of the fact that the original patent has expired. The implication is that these tools embody the invention in a way that continues to cause harm or that their use crosses some legal boundary even after the patent term ended. The respondent, Tandhan Polyplast, presumably contested this characterisation, pushing back on the claim that expired-patent tooling can still be treated as infringing material. The legal friction here is not about who invented what first, but about a deeper, more technical question: do these specific moulds and dyes, as physical objects, cross the line from legitimate post-expiry manufacturing into infringement? This is precisely the kind of question that lawyers cannot answer alone, because it demands hands-on technical scrutiny.

Rather than ruling on the merits in this interim stage, the court recognised that the core dispute whether the moulds and dyes are infringing material is a complex question of fact and technical opinion that cannot be resolved through legal argument alone. The court considered the need for expert determination to untangle this factual knot. Under Section 115 of the Indian Patent Act, 1970, the court has the power to appoint an independent scientific adviser to assist in determining such questions of fact or opinion that do not involve legal interpretation. The outcome of the application itself remains pending, with the expert determination process positioned as the likely path forward to resolve the technical heart of the dispute.

For founders and IP professionals, this case is a powerful reminder that patent expiry is not always the finish line. If your business relies on specialised moulds, dyes, or proprietary tooling, you need to think beyond the patent certificate itself and consider how those physical assets might become the next battleground. More importantly, when a dispute turns on technical questions that lawyers alone cannot resolve, do not be surprised when the court invokes its power under Section 115 of the Indian Patent Act, 1970 to bring in an independent scientific adviser. Build your legal strategy with the expectation that expert determination may be ordered, and ensure your technical documentation is airtight, because in the post-expiry world, the moulds may matter more than the patent.