Introduction
Patent law is designed to balance innovation with fair market competition. While patents grant exclusive rights to inventors, courts must ensure that these rights are exercised within the bounds of equity and public interest. The Delhi High Court's judgment in Mold-Tek Packaging Ltd. v. Pronton Plast Pack Pvt. Ltd., reaffirms this balance. It highlights the necessity of proper infringement analysis and clarifies the legal standards for equitable relief in patent litigation.
Understanding Patent Infringement in India
Under Section 48 of the Patents Act, 1970 (Rights of patentees), a patentee has the exclusive right to prevent others from making, using, offering for sale, selling, or importing the patented product or process without consent. "While the Patents Act, 1970 does not provide an explicit definition of 'infringement,' Section 48 delineates the scope of a patentee's exclusive rights, and any unauthorised use falling within this scope is treated as infringement."
Indian courts have evolved a jurisprudence where infringement is determined through a comparison of the defendant's product with the patent's claims, not just with the patentee's product. This is known as a "product-to-patent" comparison. The aim is to see whether the essential features of the patented claims are being appropriated by the defendant.
The Role of Equitable Relief in Patent Law
Equitable remedies such as interim injunctions are governed by three well-established principles:
- Prima facie case
- Balance of convenience
- Irreparable harm
In patent cases, courts add a fourth layer: the defendant's ability to raise a "credible challenge" to the patent's validity. This ensures that unworthy patents do not get judicial protection merely because they were granted by the Patent Office.
Case Background: Mold-Tek v. Pronton
Mold-Tek Packaging Ltd. held two patents:
- IN'417: Tamper-Evident Leak-Proof Pail Closure System
- IN'724: Tamper-Proof Lid with Integrated Spout
These inventions were related to plastic lids used for food containers. Mold-Tek claimed that Pronton Plast Pack was manufacturing a lid that infringed its patents. The Commercial Court initially granted an ex parte interim injunction in December 2023, restraining Pronton from selling the allegedly infringing products.
However, Pronton filed an application under Order XXXIX Rule 4 CPC, seeking to vacate the injunction. The Commercial Court granted this on 2 May 2024, citing differences in product features and failure by Mold-Tek to disclose relevant prior art. Mold-Tek appealed the decision.
Delhi High Court's Analysis and Ruling
The High Court's ruling focused on two main axes:
- Whether infringement had occurred?
- Whether the defendant had raised a credible challenge to the patent's validity?
1. Product-to-Patent Comparison is Essential
The High Court criticized the Commercial Court for conducting a product-to-product comparison instead of comparing the defendant's product with the patented claims. It emphasized that the correct approach is to map the defendant's product onto the specifications and claims of the patent.
The Court held:
"The comparison has to be between the defendant's product and the complete specifications of the plaintiff's patent, not with the plaintiff's product."
This observation aligns with global best practices and ensures that infringement is not assessed superficially but based on the scope of the claims.
2. Credible Challenge Standard Clarified
The Court reiterated that a defendant could escape interim injunction if it raises a credible challenge under Section 107 (Defences, etc., in suits for infringement) of the Patents Act 1970. A credible challenge implies that the patent is vulnerable to revocation under any of the grounds in Section 64, such as lack of novelty or inventive step.
Importantly, the Court stated that:
"A credible challenge is not a fanciful, theoretical or speculative defence. It must be backed by scientific material and expert evidence."
In the present case, Pronton cited expired patent IN'276 and other prior art documents. However, the Court found that the Commercial Court failed to map these prior arts against the suit patents to determine whether they truly undermined novelty or inventiveness.
3. Misplaced Burden of Proof
The High Court criticized the Commercial Court for shifting the burden of proving novelty onto the plaintiff. The law clearly places the burden on the defendant to prove invalidity when it invokes Section 107 as a defence.
The Court observed:
"Once the plaintiff establishes prima facie infringement, the burden to establish vulnerability lies entirely with the defendant."
This interpretation reinforces the legal framework that protects genuine innovators while providing a fair chance to defendants who raise substantial objections.
4. Suppression of Material Facts Must Be Proved
While the Commercial Court had accused Mold-Tek of suppressing prior art, the High Court found no clear evidence or reasoned finding to support this. It held that equitable relief should not be denied merely on allegations of suppression unless they are substantiated.
Relevance and Broader Implications
The ruling in Mold-Tek v. Pronton is a reaffirmation of essential doctrines in patent litigation:
- Infringement must be determined through precise legal analysis.
- Equitable relief should be granted or denied based on sound reasoning, not mere assumptions.
- Burdens of proof must be correctly allocated.
- A "credible challenge" must rise above speculative doubt and be supported by expert insight.
In a jurisdiction where patent litigation is increasing, especially in pharmaceuticals, biotech, and manufacturing, this ruling provides a strong procedural and doctrinal foundation.
Conclusion
The Delhi High Court's decision in Mold-Tek v. Pronton offers a robust framework for adjudicating interim relief in patent disputes. It restores focus on rigorous infringement analysis, reaffirms the burden of proof standards, and preserves the equitable nature of injunctive relief. For patentees and defendants alike, the message is clear: claims and defences must be legally and technically robust, and courts will demand nothing less.
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