IP Law Daily, PATENT—N.D. Tex.: Preliminary injunction denied in patent infringement dispute concerning molded equipment pads with arc-shaped ribs, (Jul 24, 2026)

By Carolin Dennis, B.Sc., LL.B., LL.M.

The district court found that the patent owner’s six-month delay in filing the motion for preliminary injunction undermined its position of irreparable harm or urgency.

The U.S. District Court in Dallas denied a patent owner’s motion for a preliminary injunction because it did not meet its burden to demonstrate a substantial likelihood of success on the merits and failed to demonstrate a likelihood of irreparable harm in the absence of a preliminary injunction. Additionally, the district court granted in part and denied in part DuraPlas, LP’s motion to strike (DuraPlas, LP v. DiversiTech Corp., No. 3:25-cv-01310-K (N.D. Tex. Jul. 20, 2026)).

Background. DiversiTech Corporation (DiversiTech) and DuraPlas, LP (DuraPlas) are competitors in the US plastic HVAC/R equipment pad market. DiversiTech alleged that DuraPlas infringed its U.S. Patent No. 12,312,123 (’123 Patent) along with other patents. DiversiTech moved pursuant to Federal Rule of Civil Procedure 65(a) and 35 U.S.C. § 283 for a preliminary injunction based on its positions that DuraPlas’s PolarPad products likely infringed claims 1, 4–7, and/or 9 of the ’123 Patent, that the ’123 Patent is likely valid, that DiversiTech has suffered and will continue to suffer irreparable harm from DuraPlas’s infringement absent a preliminary injunction, and that the balance of equities and public interest favored a preliminary injunction. DuraPlas moved to strike Section I of DiversiTech’s Reply in Support of Preliminary Injunction as well as the appendix attached to that brief based on its positions that DiversiTech improperly made new arguments for the first time in that brief and improperly attached over 200 pages of new evidence in the appendix attached to that brief. In the alternative, DuraPlas requests permission to file a sur-reply addressing the alleged new arguments and evidence.

Preliminary injunction. The district court found that DiversiTech had not established a likelihood of success on the merits because DuraPlas raised substantial questions that the relevant claims of the ’123 Patent may be invalid. Citing Titan Tire Corp. v. Case New Holland, Inc., 566 F.3d 1372 (Fed. Cir. 2009), the district court emphasized that at this stage, the accused infringer need not make out a case of actual invalidity to avoid a preliminary injunction, but need only show a substantial question of invalidity. If challenged, the patent owner must show it is more likely than not to prevail over an invalidity challenge.

The district court found that at the time DiversiTech filed its motion for preliminary injunction, it had already received DuraPlas’s invalidity contentions. However, DiversiTech did not address any invalidity position that DuraPlas had already disclosed to DiversiTech in DuraPlas’s invalidity contentions. Given that DiversiTech failed to address disclosed invalidity positions in its opening brief and waited until its reply to present arguments and evidence related to those disclosed invalidity positions, the district court declined to rely on the new arguments and evidence submitted by DiversiTech in its reply brief and associated appendix. However, the district court noted that even if considered all of the Reply in Support of Preliminary Injunction, it would still deny the motion for preliminary injunction because it did not address the invalidity arguments related to the Hef-T-Pad prior art submitted by DuraPlas not only in its invalidity contentions but in its Opposition to Preliminary Injunction.

The district court also noted that DiversiTech has not shown it is more likely than not to prevail over DuraPlas’s invalidity challenge. In particular, DiversiTech never provides any indication in its Reply in Support of Preliminary Injunction, let alone in its Brief in Support of Preliminary Injunction, of why the Hef-T-Pad prior art does not anticipate or render obvious the asserted claims of the ’123 Patent, as demonstrated by DuraPlas in its invalidity contentions and Opposition to Preliminary Injunction.

In assessing irreparable harm, the district court found that DiversiTech waited to seek a preliminary injunction for over six months after DuraPlas filed its original complaint including declaratory judgment claims related to the ’123 Patent. The six-month delay here, at a minimum, undercuts DiversiTech’s argument that it is likely to establish irreparable harm in the absence of a preliminary injunction. Additionally, the district court noted that DiversiTech’s failure to include all of the relevant evidence in the original appendix attached to its motion for preliminary injunction after DiversiTech had already received DuraPlas’s invalidity contentions served only to prompt the motion to strike and create additional delay. Thus, DiversiTech’s delay in filing the motion for preliminary injunction combined with its failure to submit arguments and evidence with that motion in light of disclosed invalidity positions evidence a lack of urgency.

Lastly, the district court noted that the DuraPlas stated that it has permanently ceased manufacturing and selling Version 1 PolarPads, and also removed the Version 1 molds from its manufacturing facility and transitioned its website and social media accounts to promote only Version 2 pads. Based on these facts, and the fact that the present motion relates only to Version 1 PolarPads, the district court found that DiversiTech failed to establish the existence of a substantial threat of irreparable harm that will likely result absent injunctive relief or establish that the alleged harm cannot be undone through monetary remedies.

Therefore, the district court concluded that DiversiTech did not meet its burden of establishing entitlement to a preliminary injunction.

Motion to strike. The district court granted the motion to strike to the extent it requested the court strike the appendix filed with the Reply in Support of Preliminary Injunction and the new arguments in Section I of the Reply in Support of Preliminary Injunction, including arguments that rely upon the appendix filed with the Reply in Support of Preliminary Injunction. However, the district court denied the motion to strike to the extent it requested permission to file a sur-reply brief in opposition to the motion for preliminary injunction. DiversiTech’s request for retroactive leave to file its reply appendix was also denied.

The Case is No. 3:25-cv-01310-K.

Judge: Kinkeade, E.

Attorneys: Craig B. Florence (Foley & Lardner LLP) for DuraPlas LP. Victor C. Johnson (Dentons U.S. LLP) for DiversiTech Corp.

Companies: DuraPlas LP; DiversiTech Corp.

Cases: Patent TexasNews