Mold Tek Packaging Limited v. Pronton Plast Pack Pvt. Ltd.

High Court of Delhi | Division Bench | 11 July 2025 Case Number: FAO (COMM) 114/2024, CM APPL. 34224/2024 & CM APPL. 34226/2024 Bench: Hon’ble Mr. Justice C. Hari Shankar and Hon’ble Mr. Justice Ajay Digpaul

BACKGROUND

The appellant, Mold Tek Packaging Limited, was the plaintiff in CS (Comm) 668/2023, instituted before the learned District Judge (Commercial), Patiala House Courts (“the learned Commercial Court”). The appellant is the registered proprietor of two patents: IN 401417 (“IN’417”), in respect of an invention titled “Tamper-Evident Leak Proof Pail Closure Systems,” and IN 298724 (“IN’724”), in respect of an invention titled “A Tamper Proof Lid Having Spout For Containers and Process For Its Manufacture.” Both patents together are referred to as “the suit patents.”

The suit patents relate to a lid used to cover containers, which the parties indicated are used for storage and transport of food items. The inventive features of IN’417, as explained by Mr. Jayant Mehta, learned Senior Counsel for the appellant, are that the lid has small projections called lugs across its edge that enable the lid to be affixed and locked to the container such that, once locked, it cannot be removed; the lower part of the lid bearing the lugs becomes integral to the container; the upper part of the lid is connected to the lower part by a tear band; the tear band must be torn to detach the upper part; and if the upper part is detached and replaced without the tear band, the absence of the tear band reveals tampering rendering the lid both “tamper proof” and “tamper evident.” IN’724 relates principally to a spout on the upper part of the lid, which allows partial discharge of contents without removing the lid entirely, the spout itself being integrated into the lid such that it too is tamper proof and tamper evident.

The appellant instituted CS (Comm) 668/2023 alleging that the respondent, Pronton Plast Pack Pvt. Ltd., was manufacturing and selling a lid with a spout attachment that infringed the suit patents. The suit was accompanied by an application under Order XXXIX Rules 1 and 2 of the Code of Civil Procedure, 1908 (“CPC”) seeking an interim injunction. By order dated 20 December 2023, the learned Commercial Court granted an ex parte ad interim injunction restraining the respondent from manufacturing, marketing, using, selling, offering for sale, importing, distributing, advertising, exporting or otherwise dealing in any product infringing Indian Patent Nos. IN’417 and IN’724, holding that a prima facie case had been made out, that the balance of convenience lay with the appellant and that absent the injunction the appellant’s business and goodwill would be injured.

The respondent thereafter filed an application under Order XXXIX Rule 4 of the CPC seeking vacation of this ex parte ad interim injunction. By the impugned order dated 2 May 2024, the learned Commercial Court allowed the respondent’s application and vacated the ad interim injunction. The reasoning of the learned Commercial Court proceeded broadly as follows: it set out general principles of patent injunction law (paragraphs 8.1 to 8.11), including that the Patents Act does not statutorily define infringement, that Section 107(1) of the Patents Act permits every ground of revocation under Section 64 to be raised as a defence, that grant of a patent does not carry a presumption of validity (unlike registration of a trademark) and that the conduct of a plaintiff seeking equitable relief including any suppression of material facts is relevant to the grant or refusal of interim injunction. The learned Commercial Court then held that the respondent’s argument that its products were dissimilar to the appellant’s products constituted “a valid credible defence” (paragraph 12); that the Controller of Patents, in granting the suit patents, had not had occasion to consider whether the claimed improvement over prior art was sufficient to merit grant of a patent (paragraph 13); that the onus was on the appellant-plaintiff to show novelty and its adoption by the defendant, given that the appellant itself had pleaded that IN’417 was an improvement over earlier prior art (paragraph 14); that with respect to IN’724, an earlier patent of the appellant, IN’276, covering a similar product, had ceased to exist and that the appellant had not disclosed the status of IN’276, amounting to suppression of a material fact (paragraph 15); and concluded, on this basis, that the respondent had succeeded in raising a credible challenge to the suit patents on grounds of novelty vis-à-vis prior art, as well as suppression of material facts by the appellant, warranting refusal of interim injunction (paragraph 16). The learned Commercial Court accordingly rejected the appellant’s prayer for interlocutory injunction and allowed the respondent’s Order XXXIX Rule 4 application, vacating the ad interim injunction dated 20 December 2023, while clarifying that nothing in the order amounted to an expression of opinion on the merits of the case.

Aggrieved by this order, the appellant filed the present appeal under Section 13A of the Commercial Courts Act, 2015 read with Order XLIII of the CPC.

ISSUES FOR DETERMINATION

1. The first issue before the Division Bench was whether the learned Commercial Court had properly examined the threshold question in any patent infringement litigation namely, whether the respondent’s product, on a comparison with the complete specifications of the suit patents (and not merely a comparison with the appellant’s own commercial product), in fact infringed the suit patents IN’417 and IN’724.
2. The second issue was whether the learned Commercial Court had properly examined whether the respondent had discharged the onus, which Section 107(1) of the Patents Act read with Section 64 places upon a defendant raising a defence of invalidity, of establishing a “credible challenge” to the vulnerability of the suit patents to revocation and whether the mere existence of prior art documents (without any analysis of whether those documents in fact anticipated or rendered obvious the claimed inventions) was sufficient to discharge that onus.
3. The third issue was whether the learned Commercial Court had erred in law by shifting the onus of establishing novelty from the respondent-defendant (upon whom Section 107 read with Section 64 places that onus once a Section 107 defence is raised) to the appellant-plaintiff, merely because the appellant had pleaded, in its complete specification for IN’417, that the invention was an improvement over earlier prior art.
4. The fourth issue, raised by the respondent as a fall-back submission, was whether the Division Bench, in the event it found it necessary to remand the matter, should also set aside the original ex parte ad interim injunction order dated 20 December 2023 an order that was not itself under challenge in the present appeal and require reconsideration starting from that earlier stage.
5. The fifth issue was the appropriate remedy and the stage to which the matter should be remanded, given the infirmities identified in the impugned order.

KEY HOLDINGS OF THE COURT

1. On the threshold question of infringement, the Court held that every patent infringement litigation, depending on the nature of the defence raised, ordinarily involves only two aspects: first, whether the defendant’s product infringes the suit patent; and second, where a Section 107 defence is raised, whether the defendant has raised a credible challenge to the vulnerability of the suit patent to revocation under Section 64. The Court held that the comparison for determining infringement must be conducted between the defendant’s product and the complete specifications of the suit patent that is, “product-to-patent” and not between the defendant’s product and the plaintiff’s own commercial product, that is, “product-to-product.” The Court held that Section 48 of the Patents Act prohibits the making, using, offering for sale, selling or importing of a product which forms the “subject matter of” a patent held by another and that the subject matter of a patent is to be found in its complete specifications; accordingly, the correct comparison is always between the allegedly infringing product and the patent’s complete specifications.
2. The Court held that the learned Commercial Court had failed entirely to undertake this exercise. The impugned order contained no discussion of whether the respondent’s product, mapped onto the complete specifications of the suit patents, in fact infringed them. The Court found the learned Commercial Court’s observation, in paragraph 12 of the impugned order, that “the argument of the defendant that its products are dissimilar to the plaintiff (was) a valid credible defence available to the defendant,” to be erroneous and, in the Court’s words, “ex facie” suffering “from perversity in law” since a mere argument of dissimilarity, without any examination of its merits, cannot by itself constitute a “valid credible defence.” The Court further held that the very framing of the comparison as being between the respondent’s products and “the plaintiff” (rather than between the respondent’s products and the complete specifications of the suit patents) indicated that the learned Commercial Court had conflated the issue of infringement with the issue of validity and had, in any event, applied the wrong legal standard of comparison (product-to-product rather than product-to-patent).
3. On the standard for a “credible challenge” under Section 107 read with Section 64, the Court extensively reviewed and reaffirmed the principles laid down in Strix Ltd v Maharaja Appliances Ltd, 2009 SCC OnLine Del 2825 and in the decisions of C. Hari Shankar J. (sitting singly) in Kudos Pharmaceuticals Ltd v Natco Pharma Ltd, 2024 SCC OnLine Del 1439 (itself drawing on FMC Corporation v Best Crop Science LLP, (2021) 87 PTC 217; Novartis AG v Natco Pharma Ltd, 2023 SCC OnLine Del 106; and Novartis AG v Natco Pharma Ltd, 2021 SCC OnLine Del 5340). The Court held that the onus to establish that a challenge to validity is credible rests squarely on the defendant; that a “credible challenge” is one that is not incredible, fanciful or moonshine and must, on its face, merit favourable consideration occupying “a higher pedestal than a challenge which is merely worthy of consideration”; that the standard of credibility is a high standard, not a low one, partly because the Patent Office has, prior to grant, undertaken a thorough study of validity and partly because revocation is a drastic step that is not automatic even where a prima facie ground for revocation is made out (citing Merck Sharp & Dohme Corporation v Glenmark Pharmaceuticals, (2015) 63 PTC 257 (Del-DB)); and that the mere existence of a prior art document, without any analysis of whether that prior art in fact anticipates or renders obvious the claimed invention, cannot constitute a credible challenge.
4. Applying this standard, the Court held that the learned Commercial Court had not undertaken any genuine examination of whether the respondent had raised a credible challenge to either suit patent. With respect to IN’417, the Court noted that the respondent’s principal ground for alleging vulnerability to revocation on grounds of anticipation and obviousness was based on a specific prior art document, IN 288127 (“IN’127”), filed by the appellant itself yet there was no reference anywhere in the impugned order to IN’127, despite the respondent’s reliance on it having been noted (without analysis) in paragraph 6.4 of the impugned order. With respect to IN’724, the Court held that the learned Commercial Court had treated the mere existence of an earlier, now-lapsed patent of the appellant, IN’276, covering a similar product, as itself sufficient to raise a credible challenge to IN’724’s validity, without undertaking any exercise of mapping the features of the respondent’s product or the claims of IN’724, against the complete specifications of IN’276. The Court held this assumption to be “obviously fallacious in law.”
5. On the question of onus, the Court held that the learned Commercial Court had committed a fundamental error of law in observing, in paragraph 14 of the impugned order, that because the appellant had pleaded in its complete specification for IN’417 that the invention was an improvement over earlier prior art, the onus to establish such novelty and its adoption by the defendant lay on the appellant. The Court held that in an infringement action, the onus is, at the first stage, on the plaintiff to establish infringement; once that onus is discharged, it does not shift back to the plaintiff at any subsequent stage. Thereafter, in examining a Section 107 defence, the onus to establish that the suit patent is vulnerable to invalidity on one or more of the grounds under Section 64 including absence of novelty vis-à-vis prior art lies wholly and exclusively on the defendant and this onus never shifts to the plaintiff merely because the plaintiff’s own complete specification asserts novelty over prior art. The Court held that the learned Commercial Court was “fundamentally in error” in holding otherwise.
6. On the respondent’s fall-back submission that the Court should also set aside the original ex parte ad interim injunction order dated 20 December 2023, the Court declined to do so. The Court held that this earlier order was not under challenge in the present appeal; the respondent had made a conscious choice to seek vacation of that order under Order XXXIX Rule 4 rather than to appeal against it directly and having pursued one of the two available courses of action, the respondent could not, in an appeal filed by the appellant against the subsequent Order XXXIX Rule 4 order, seek to have the Court revisit the earlier order through the back door. The Court accordingly confined itself to examining only the correctness of the impugned order dated 2 May 2024.
7. The Court held that, in view of the cumulative infirmities identified absence of any infringement analysis, absence of any genuine “credible challenge” analysis with respect to either suit patent and the fundamental error regarding onus the impugned order could not be sustained either in law or on facts. The Court was careful to clarify that it had not examined and expressed no opinion on, either of the substantive questions (whether the respondent’s products in fact infringe the suit patents or whether the respondent has succeeded in raising a credible challenge to the suit patents’ validity). The impugned order dated 2 May 2024 was quashed and set aside. The Registry was directed to register the appellant’s application under Order XXXIX Rules 1 and 2 of the CPC and the respondent’s application under Order XXXIX Rule 4 of the CPC with fresh registration numbers, the latter being restored to the file of the learned Single Judge (the suit itself, CS (Comm) 668/2023, having since been transferred to the High Court and renumbered as CS (Comm) 944/2024, consequent upon a counter-claim filed by the respondent) for consideration de novo, uninfluenced by any observation in the impugned order. The parties were directed to appear before the learned Single Judge on 25 July 2025 and to file short notes not exceeding six pages each, with indexed compilations of authorities, at least 48 hours before the next hearing, with both sides undertaking not to seek any adjournment on that date. The Court directed the learned Single Judge to take up the Order XXXIX Rule 4 application on the date fixed and decide it as expeditiously as possible. The appeal was allowed to this extent, with no order as to costs and it was directed that, pending disposal of the Order XXXIX Rule 4 application afresh, the ex parte ad interim injunction granted on 20 December 2023 would continue to remain in operation.

STATUTORY PROVISIONS INVOLVED

Section 48 of the Patents Act, 1970 sets out the rights of patentees: in respect of a product patent, the exclusive right to prevent third parties from making, using, offering for sale, selling or importing the patented product without consent; in respect of a process patent, the exclusive right to prevent third parties from using that process and from dealing in the product obtained directly by that process. The Court relied heavily on this provision to establish that “infringement,” though not expressly defined anywhere in the Patents Act (a legislative lacuna the Court expressly noted, contrasting the Patents Act unfavourably with Section 29 of the Trade Marks Act, 1999, Section 51 of the Copyright Act, 1957 and Section 22 of the Designs Act, 2000, each of which does define infringement/piracy), is to be understood as the unauthorised making, using, offering for sale, selling or importing of a product or process forming the “subject matter” of a patent, that subject matter being found in the complete specifications. This is the statutory basis for the Court’s holding that the correct comparison in an infringement analysis is “product-to-patent,” not “product-to-product.”

Section 49(1) of the Patents Act, 1970 sets out circumstances in which patent rights are not infringed (use on foreign vessels, aircraft or land vehicles temporarily or accidentally in India). The Court referred to this provision as supporting, by negative implication, the understanding of what constitutes infringement under Section 48.

Section 107(1) of the Patents Act, 1970 provides that in any suit for infringement of a patent, every ground on which the patent may be revoked under Section 64 shall be available as a ground of defence. This provision was central to the Court’s analysis: it is the statutory basis for a defendant’s right to raise a validity challenge in an infringement suit and the Court held that the onus of establishing such a challenge to the standard of a “credible challenge” rests on the defendant invoking this provision and that this onus does not shift to the plaintiff.

Section 64 of the Patents Act, 1970 sets out the grounds on which a patent may be revoked, including, among others, that the invention is not new having regard to what was publicly known or used in India or published before the priority date (clause (e)); that the invention is obvious and does not involve any inventive step (clause (f), as referenced in the discussion); and other grounds relating to entitlement, wrongful obtaining, insufficiency of disclosure, false suggestion and non-disclosure under Section 8. The Court extensively quoted this provision and held that a defendant’s Section 107 defence must be assessed against these specific statutory grounds, requiring a genuine, evidence-based “credible challenge” analysis rather than a bare assertion that prior art exists.

Order XXXIX Rules 1 and 2 of the Code of Civil Procedure, 1908 govern the grant of temporary injunctions. The appellant’s original application for interim injunction, allowed ex parte by the order dated 20 December 2023, was filed under these provisions.

Order XXXIX Rule 4 of the Code of Civil Procedure, 1908 governs applications for discharge, variation or setting aside of an order of injunction. The respondent’s application seeking vacation of the ex parte ad interim injunction was filed under this provision and the impugned order disposing of that application was the subject of the present appeal.

Section 13A of the Commercial Courts Act, 2015 read with Order XLIII of the Code of Civil Procedure, 1908 provided the statutory basis for the present appeal against the order disposing of the Order XXXIX Rule 4 application.

REASONING OF THE COURT

The Division Bench’s reasoning proceeded by first articulating, as a matter of general principle, the analytical framework that any court hearing a patent infringement matter whether at the interim or final stage must apply and then systematically testing the impugned order against that framework to identify where it had gone wrong.

The Court began by addressing what it identified as a genuine legislative lacuna: unlike the Trade Marks Act, Copyright Act and Designs Act, the Patents Act contains no express definition of “infringement.” The Court navigated this gap by reasoning from Section 48, which defines the patentee’s exclusive rights in terms of preventing unauthorised making, using, selling, offering for sale or importing of the product or process forming the “subject matter” of the patent. Since the subject matter of a patent resides in its complete specifications, the Court reasoned that the only legally correct method of assessing infringement is to compare the allegedly infringing product against those complete specifications not against the patentee’s own commercial embodiment of the invention, since a patentee’s commercial product, while presumably embodying the patented invention, is not itself the measure of the patent’s legal scope. The Court found this product-to-patent (rather than product-to-product) standard to have been entirely disregarded by the learned Commercial Court, which had framed its entire analysis (and ultimately its erroneous “valid credible defence” finding) around a comparison of the respondent’s product with “the plaintiff” meaning, evidently, the appellant’s own product.

Having established the infringement framework, the Court turned to the second analytical stage applicable where, as here, a Section 107 validity defence is also raised. Drawing on a substantial body of precedent both Division Bench authority (Strix Ltd) and the detailed elaboration in Kudos Pharmaceuticals (itself building on FMC Corporation and the two Novartis decisions) the Court reconstructed the settled standard for a “credible challenge”: it must not be incredible, fanciful or speculative; it must, on its face, merit favourable consideration: a standard higher than mere “worthiness of consideration”; and the burden of establishing this lies squarely on the party asserting invalidity. The Court explained the policy rationale for this relatively demanding standard the Patent Office’s prior, careful examination of validity before grant and the established principle (from the Division Bench in Merck v Glenmark) that revocation is never automatic even where a prima facie ground exists, but remains a matter calling for considered discretion. Measured against this standard, the Court found that the learned Commercial Court had done no more than note the bare existence of prior art documents (IN’127 for IN’417 and the lapsed patent IN’276 for IN’724) without undertaking the necessary substantive analysis comparing the claims or features of the suit patents against the teachings of those specific prior art documents to determine whether anticipation or obviousness was genuinely made out. The mere citation of a prior art reference, without this comparative analysis, the Court held, falls well short of a “credible challenge” and cannot, by itself, justify refusal of interim relief.

The Court’s third and most pointed criticism concerned the question of onus. Here the Court identified a basic conceptual confusion in the impugned order: the learned Commercial Court appeared to have reasoned that because the appellant’s own complete specification for IN’417 asserted that the invention was novel and represented an improvement over prior art, the appellant bore the burden of proving that novelty in the suit. The Court explained that this conflates two analytically distinct burdens that arise at two distinct stages of an infringement action: the plaintiff’s initial burden to establish infringement (i.e., that the defendant’s product falls within the patent’s claims) and the defendant’s separate and independent burden, arising only once a Section 107 defence is raised, to establish that the patent is vulnerable to revocation on one of the Section 64 grounds. A patentee’s own assertion of novelty in its specification a standard and necessary component of any patent application cannot retroactively transfer the burden of disproving invalidity from the party challenging validity (the defendant) to the patentee. The Court regarded this error as “fundamental,” reflecting a basic misunderstanding of how the burdens allocated by Sections 107 and 64 operate in practice.

Finally, on the question of remedy, the Court was careful to distinguish between the order properly before it (the Order XXXIX Rule 4 order) and the earlier, separate order (the ex parte ad interim injunction) that the respondent sought to have reopened through its fall-back submission. The Court applied a straightforward procedural principle: a party that elects one of two available remedial paths (here, seeking vacation under Order XXXIX Rule 4 rather than filing a direct appeal against the ex parte order) cannot, having made that election, later seek to avail of the other path through a procedural side-door in an appeal initiated by the opposing party. The Court accordingly confined the scope of its intervention strictly to the order actually under appeal, while ensuring through its direction that the original ad interim injunction would continue pending fresh disposal of the Rule 4 application that the practical consequence of setting aside the flawed vacation order would be to restore the interim status quo until the matter could be properly reconsidered.

DOCTRINAL SIGNIFICANCE

This judgment makes a substantial and clearly articulated contribution to Indian patent procedural jurisprudence, particularly with respect to the analytical discipline required of courts adjudicating Order XXXIX Rule 4 applications in patent infringement suits.

The most significant doctrinal contribution is the Court’s clear and emphatic articulation of the “product-to-patent” (and not “product-to-product”) standard for assessing infringement. While this principle is not new to Indian patent law, its restatement here accompanied by the Court’s frank observation regarding the absence of a statutory definition of “infringement” in the Patents Act and its express call for legislative attention to this gap is a useful clarificatory contribution that should assist trial courts in avoiding the precise analytical error committed by the learned Commercial Court in this case.

The judgment’s consolidation and restatement of the “credible challenge” standard drawing together the Division Bench authority in Strix Ltd, the persuasive single-judge authorities in Kudos Pharmaceuticals, Novartis I, Novartis II and FMC Corporation and the Division Bench authority in Merck v Glenmark on the discretionary (non-automatic) nature of revocation provides a comprehensive and readily citable statement of this standard for future cases. The judgment’s insistence that a “credible challenge” requires genuine engagement with the specific content of prior art documents, rather than their bare citation, is likely to have a meaningful disciplining effect on how validity challenges are pleaded and adjudicated at the interim stage.

The judgment’s clarification on the burden of proof that the burden under Section 107 read with Section 64 to establish invalidity rests exclusively on the defendant and never shifts to the plaintiff, irrespective of how the plaintiff’s own complete specification characterises the invention’s relationship to prior art is a particularly important corrective. This clarification addresses what could otherwise become a recurring error in patent litigation, where defendants might seek to exploit a patentee’s own (entirely conventional and necessary) assertions of novelty in its specification as a device for improperly shifting the burden of proof onto the patentee at the interim injunction stage.

The judgment’s careful procedural reasoning concerning the scope of an appeal against an Order XXXIX Rule 4 order confirming that such an appeal cannot be used as a vehicle to reopen an earlier, separate and unappealed ex parte injunction order is also a useful procedural clarification, reinforcing the principle that parties must make and adhere to their elected procedural strategies.

Finally, the judgment is notable for the Division Bench’s evident care in confining its intervention to the level of legal principle and analytical methodology, while expressly and repeatedly disclaiming any opinion on the substantive merits both as to infringement and as to the credibility of the validity challenge. This self-restraint, combined with the practical direction preserving the interim status quo pending fresh adjudication, reflects a considered effort to correct an analytically deficient order without prematurely resolving the underlying commercial dispute between the parties, leaving that task, properly, to the learned Single Judge on remand.

Frequently Asked Questions:

Q1. What is the product-to-patent standard in Indian patent infringement cases?

The product-to-patent standard requires courts to compare the defendant’s product against the complete specifications of the suit patent – not against the plaintiff’s own commercial product. This was reaffirmed by the Delhi High Court Division Bench in Mold Tek Packaging v. Pronton Plast.

Q2. What is a credible challenge under Section 107 of the Patents Act 1970?

A credible challenge is a defendant’s challenge to the validity of a patent in an infringement suit. It must be more than mere citation of prior art – it requires substantive analysis showing the patent is vulnerable to revocation under Section 64 of the Patents Act 1970.

Q3. Who bears the burden of proof in a patent infringement suit in India?

The plaintiff bears the initial burden to establish infringement. Once a Section 107 defence is raised, the burden to establish invalidity shifts exclusively to the defendant. This burden never shifts back to the plaintiff merely because the patent specification asserts novelty over prior art.

Q4. What is Order XXXIX Rule 4 CPC in patent litigation?

Order XXXIX Rule 4 of the Code of Civil Procedure 1908 allows a defendant to apply for vacation or modification of an interim injunction already granted against them. In patent cases, this application triggers a fresh examination of infringement and validity at the interim stage.

Q5. Can a patent interim injunction be vacated on grounds of invalidity in India?

Yes, but only if the defendant raises a credible challenge to the patent’s validity under Section 107 read with Section 64 of the Patents Act 1970. A bare assertion that prior art exists – without comparative analysis – is insufficient to vacate an interim injunction.

Related Reading on Patent Law in India

• Landmark Judgements on Patent Law in India – Click here
• Recent Case Laws on Patents – Click here
• Patentability Criteria in India – Click here
• Patent Infringement under Indian Law – Click here
• Patent Revocation under Section 64 – Patents Act 1970 – Click here
• Anti-Suit Injunctions in Indian SEP Litigation – InterDigital v. Xiaomi – Click here

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