DCT
2:25-cv-02119
Dongguan Aoxun Plastic Products Co Ltd v. Guangdong Willing Technology Corp
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiffs: Dongguan Aoxun Plastic Products Co., Ltd. and Shenzhen Migao Trading Co., Ltd d/b/a MI GAO (China)
- Defendant: Guangdong Willing Technology Corporation (China)
- Plaintiffs’ Counsel: LawMay P.C.; Law Office of Carl J. Marquardt PLLC
- Case Identification: 2:25-cv-02119, W.D. Wash., 10/28/2025
- Venue Allegations: Plaintiffs allege venue is proper in the Western District of Washington because Defendant submitted its patent infringement complaint through Amazon's Patent Evaluation Express (APEX) procedure, which is administered from Amazon's principal place of business in Seattle.
- Core Dispute: Plaintiffs seek a declaratory judgment that their silicone warming mat product does not infringe Defendant's patent, and that the patent-in-suit is invalid and unenforceable.
- Technical Context: The technology concerns flexible electric heating mats, often used as countertop devices for keeping food warm, designed for easy storage.
- Key Procedural History: The complaint alleges this action was precipitated by Defendant's filing of a complaint through Amazon's APEX procedure. A central allegation is that Defendant initiated this enforcement action despite its corresponding Chinese priority patent having been declared invalid for obviousness by the China National Intellectual Property Administration (CNIPA) approximately six months prior. Plaintiffs also allege they sent a detailed non-infringement letter to Defendant, which was ignored.
Case Timeline
| Date | Event |
|---|---|
| 2023-04-27 | ’244 Patent Priority Date (Chinese Application) |
| 2025-04-25 | CNIPA issues decision invalidating Chinese priority patent |
| 2025-07-01 | ’244 Patent Issue Date |
| 2025-10-14 | Defendant initiates Amazon APEX proceeding against Plaintiff |
| 2025-10-16 | Plaintiff's counsel sends non-infringement letter to Defendant |
| 2025-10-28 | Complaint for Declaratory Judgment filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 12,349,244 - "Flexible heat preservation board with heating wire encapsulated therein"
The Invention Explained
- Problem Addressed: The patent addresses the problem that conventional meal heating devices are often made of rigid materials like metal or glass, which makes them difficult to store and occupy a large amount of space when not in use (’244 Patent, col. 2:21-25).
- The Patented Solution: The invention is a flexible heating board where a heating wire is secured within a specially designed groove on a flexible pad. The key feature is the groove's internal structure: two protrusions, one on each inner wall, face each other. The distance between them is less than the heating wire's diameter, creating a friction fit that mechanically holds the wire in place. A liquid adhesive is then added to fully encapsulate the wire, protrusions, and groove, providing a second layer of fixation. This dual-fixation mechanism is designed to prevent the wire from dislodging when the mat is repeatedly rolled up for storage (’244 Patent, Abstract; col. 3:5-28).
- Technical Importance: The claimed structure aims to create a durable, flexible heating product that maintains uniform heating and structural integrity despite repeated flexing and rolling (’244 Patent, col. 4:26-33).
Key Claims at a Glance
- The complaint identifies Claim 1 as the sole independent claim asserted against Plaintiffs (Compl. ¶29).
- The essential elements of Claim 1 include:
- A flexible heat preservation board comprising a heating pad, a heating wire, and a liquid adhesive.
- The heating pad has a groove in a winding pattern.
- The groove has a first inner surface with a first protrusion and a second inner surface with a second protrusion, where the protrusions face each other.
- The distance between the protrusions' edges is less than the diameter of the heating wire.
- An "open accommodating space" is defined by the groove's bottom and the lower surfaces of the protrusions for receiving the wire.
- Gaps are formed between the lower surfaces of the protrusions and the outer surface of the heating wire.
- The liquid adhesive encapsulates the first protrusion, the second protrusion, and the heating wire within the groove.
- Both the heating pad and heating wire are flexible.
- The complaint does not explicitly reserve the right to assert dependent claims, but seeks a declaratory judgment of non-infringement for "any valid and enforceable claim of the '244 Patent" (Compl. ¶40).
III. The Accused Instrumentality
Product Identification
The accused instrumentality is a silicone warming mat for food, sold on Amazon.com under the "MI GAO" brand and identified by ASIN B0DRHWT27P (the "Warming Mat") (Compl. ¶¶10, 21).
Functionality and Market Context
The complaint describes the product as a "foldable countertop heating mat" sold to U.S. consumers through Plaintiffs' Amazon storefront (Compl. ¶¶20, 22). It alleges that Amazon is MI GAO's primary U.S. sales channel and that Defendant's APEX assertion threatens the product with delisting, which would cause immediate and irreparable harm (Compl. ¶¶23-24). The complaint does not provide significant technical detail regarding the internal construction of the Warming Mat.
IV. Analysis of Infringement Allegations
This action is for a declaratory judgment of non-infringement. The following table summarizes Plaintiffs' assertions that their Warming Mat lacks key elements of the asserted claim.
No probative visual evidence provided in complaint.
’244 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a heating pad, provided with a power supplier... | The complaint alleges the "power supplier" element is "missing, materially different, or performs a distinct function inconsistent with the claim language." | ¶44 | col. 4:64-67 |
| wherein a first inner surface of the groove is provided with a first protrusion, a second inner surface of the groove is provided with a second protrusion, and the first protrusion and the second protrusion face each other; a distance between a first edge of the first protrusion and a second edge of the second protrusion is less than a diameter of the heating wire... | The complaint alleges the Warming Mat does not include the claimed structure of "first and second protrusions" that face each other to secure the heating wire. | ¶¶42, 44 | col. 5:7-14 |
| the liquid adhesive encapsulates the first protrusion, the second protrusion, and the heating wire in the groove... | The complaint alleges the "liquid adhesive encapsulation" element is "missing, materially different, or performs a distinct function." | ¶44 | col. 5:18-20 |
Identified Points of Contention
- Factual Questions: The central dispute appears to be factual: does the accused Warming Mat's internal structure include two opposing protrusions within a groove that mechanically grip the heating wire before being sealed with an adhesive? The complaint asserts a material difference in construction (Compl. ¶43).
- Scope Questions: The case may raise the question of whether any internal ridge or structural feature within the accused product's heating element channel can be characterized as the claimed "protrusions." The complaint's allegation that these elements are "missing" suggests Plaintiffs will argue for a narrow interpretation of the claim's structural requirements (Compl. ¶44).
V. Key Claim Terms for Construction
The Term: "protrusion"
- Context and Importance: This term is central to the patent's purported novelty, describing the specific mechanical structure used to grip the heating wire. Plaintiffs explicitly identify the "first and second protrusions" as a feature missing from their product (Compl. ¶44). The patentability of the claims, as distinguished from prior art during prosecution, may have depended on the specific features of this element (Compl. ¶43).
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The term is not explicitly defined in the patent, which could support an argument that it encompasses any feature that juts out from the inner surface of the groove.
- Evidence for a Narrower Interpretation: The specification describes embodiments where the protrusions are "of a bar-shaped structure" with a "semicircular" cross-section (’244 Patent, col. 3:10-17; Fig. 2). The patent also describes a specific function where the flexible protrusions "tend to expand outwardly when extruded by the heating wire" and then return to their original state to achieve an "effective fixation effect" (’244 Patent, col. 3:21-28). This language may support a narrower construction tied to a specific shape and mechanical behavior.
The Term: "liquid adhesive encapsulates"
- Context and Importance: This term defines the final step in securing the heating wire. Plaintiffs allege this feature is also "missing" or "materially different" in their product (Compl. ¶44). The dispute may turn on whether the accused product uses an adhesive in a manner that constitutes "encapsulation" as required by the claim.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: A party could argue "encapsulates" simply means to enclose or cover with an adhesive.
- Evidence for a Narrower Interpretation: The specification describes a two-step fixation process, where the protrusions provide a "first fixation effect" and the liquid adhesive "fills gaps in the groove" to achieve a "second fixation effect" (’244 Patent, col. 3:43-47). This suggests "encapsulates" requires more than simple adhesion; it implies a process of filling the remaining space around the wire and protrusions to complete the seal.
VI. Other Allegations
Indirect Infringement
The complaint makes a general denial of contributory infringement or inducement but provides no specific factual allegations, focusing instead on the lack of direct infringement (Compl. ¶40).
Willful Infringement
While this is a declaratory judgment action, the complaint contains significant allegations that Defendant engaged in "bad-faith enforcement" (Compl. ¶¶30-37, 53). The basis for this claim is the allegation that Defendant knew the ’244 Patent was invalid based on the CNIPA's prior invalidation of its Chinese priority patent on obviousness grounds, yet proceeded with the APEX enforcement action regardless (Compl. ¶¶33-34). These allegations form the basis for Plaintiffs' claims of tortious interference and violations of state and federal law (Compl. Counts III-VI).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of structural fact: does the accused MI GAO warming mat contain the specific internal groove architecture—defined by two opposing, mechanically-gripping "protrusions"—that is explicitly recited in Claim 1 of the ’244 Patent, or is its construction materially different as Plaintiffs allege?
- A second central question will concern enforcement conduct: did Defendant initiate its Amazon APEX complaint in bad faith, with knowledge that its patent was likely invalid in view of the prior art and the CNIPA's decision invalidating the corresponding Chinese priority patent? The resolution of this issue will be critical to Plaintiffs' non-patent claims and request for exceptional case status.