DCT

2:21-cv-03070

Celanese Intl Corp v. Anhui Jinhe Industrial Co Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:21-cv-03070, C.D. Cal., 04/08/2021
  • Venue Allegations: Venue is alleged based on Defendants systematically transacting business, residing, maintaining warehouses, and committing acts of infringement—including selling, distributing, and importing infringing products—within the Central District of California.
  • Core Dispute: Plaintiff alleges that Defendant’s acesulfame potassium, a high-intensity artificial sweetener, is manufactured and/or purified using processes that infringe five U.S. patents.
  • Technical Context: The patents relate to chemical processes for manufacturing high-purity acesulfame potassium ("Ace-K") by controlling specific reaction conditions to minimize the formation or presence of undesirable impurities.
  • Key Procedural History: The asserted patents are grouped into two distinct families: the ’546 Patent Family (’546, ’004, and ’098 patents) and the ’999 Patent Family (’163 and ’095 patents). The complaint notes that patents within each family are continuations of earlier-filed applications, suggesting a related inventive focus for each group.

Case Timeline

Date Event
2016-09-21 Earliest Priority Date for all Asserted Patents
2018-07-17 U.S. Patent No. 10,023,546 Issues
2019-02-19 U.S. Patent No. 10,208,004 Issues
2019-03-19 U.S. Patent No. 10,233,163 Issues
2020-03-17 U.S. Patent No. 10,590,098 Issues
2020-03-17 U.S. Patent No. 10,590,095 Issues
2021-04-08 Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 10,023,546 - "Acesulfame Potassium Compositions and Processes for Producing Same"

Issued July 17, 2018

The Invention Explained

  • Problem Addressed: Conventional processes for producing acesulfame potassium create undesirable impurities, such as 5-chloro-acesulfame potassium, which are difficult and costly to separate from the final product due to their similar chemical structures (Compl. ¶30-32; ’546 Patent, col. 1:43-52).
  • The Patented Solution: The patent describes a process that minimizes the formation of these chlorine-based impurities by controlling the "contact time" between the solvent (e.g., dichloromethane) and the cyclizing agent (e.g., sulfur trioxide). By ensuring this contact time is less than 60 minutes before the mixture is reacted with the acetoacetamide salt, the invention purports to retard the side reactions that produce the problematic impurities (Compl. ¶34; ’546 Patent, col. 4:10-28).
  • Technical Importance: This approach allows for the production of high-purity acesulfame potassium while reducing or eliminating the need for subsequent, difficult purification steps, which results in substantial cost savings (Compl. ¶35).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶80).
  • The essential elements of claim 1 are:
    • A process for producing a finished acesulfame potassium composition.
    • (a) Contacting a cyclizing agent and a specific type of solvent to form a cyclizing agent composition.
    • (b) Reacting an acetoacetamide salt with the cyclizing agent composition to form a cyclic sulfur trioxide adduct.
    • (c) Forming from the adduct the finished acesulfame potassium composition, comprising less than 35 wppm 5-chloro-acesulfame potassium.
    • Wherein the contact time from the beginning of step (a) to the beginning of step (b) is less than 60 minutes.
  • The complaint alleges infringement of "at least claim 1," thereby reserving the right to assert additional claims (Compl. ¶80).

U.S. Patent No. 10,208,004 - "Acesulfame Potassium Compositions and Processes for Producing Same"

Issued February 19, 2019

The Invention Explained

  • Problem Addressed: As with the parent ’546 Patent, the invention addresses the formation of undesirable impurities, such as 5-chloro-acesulfame potassium, during the synthesis of acesulfame potassium (Compl. ¶30-32; ’004 Patent, col. 1:44-53).
  • The Patented Solution: This patent discloses a process where, in addition to limiting contact time, the cyclizing agent composition is cooled before reacting with the acetoacetamide salt. Specifically, the process requires the cyclizing agent composition to have a temperature that is lower than the initial temperature of the solvent and/or the cyclizing agent from which it was formed, a step which is alleged to further reduce impurity formation (Compl. ¶97; ’004 Patent, col. 7:46-56).
  • Technical Importance: The process is alleged to provide a lower-cost method for producing high-purity acesulfame potassium by preventing the formation of impurities that are difficult to remove (Compl. ¶101).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶94).
  • The essential elements of claim 1 are:
    • A process for producing a finished acesulfame potassium composition.
    • (a) Providing a solvent and a cyclizing agent (including sulfur trioxide) at initial temperatures.
    • (b) Contacting the solvent and cyclizing agent to form a cyclizing agent composition.
    • (c) Reacting an acetoacetamide salt with the cyclizing agent composition to form a cyclic sulfur trioxide adduct, wherein prior to this reaction, the cyclizing agent composition has a temperature lower than the initial temperature of the cyclizing agent and/or solvent.
    • (d) Forming the finished acesulfame potassium composition, comprising less than 35 wppm 5-chloro-acesulfame potassium.
    • Wherein the contact time from the beginning of step (b) to the beginning of step (c) is less than 60 minutes.
  • The complaint alleges infringement of "at least claim 1," reserving the right to assert other claims (Compl. ¶94).

U.S. Patent No. 10,590,098 - "Acesulfame Potassium Compositions and Processes for Producing Same"

Issued March 17, 2020

  • Technology Synopsis: The ’098 Patent is related to the ’004 Patent and is also directed to preventing the formation of 5-chloro-acesulfame potassium. It claims a process that combines the pre-cooling step of the ’004 Patent with a more stringent contact time requirement of "less than 15 minutes" (Compl. ¶111).
  • Asserted Claims: At least independent claim 1 (Compl. ¶108).
  • Accused Features: The complaint alleges that Defendants’ Ace-K product is made by the claimed process, as evidenced by its high purity (Compl. ¶113-114).

U.S. Patent No. 10,233,163 - "Acesulfame Potassium Compositions and Processes for Producing Same"

Issued March 19, 2019

  • Technology Synopsis: This patent, from the separate ’999 Patent Family, addresses the removal of a different impurity, acetoacetamide, from a crude acesulfame potassium composition (Compl. ¶41-43). The patented solution is a purification process involving specific temperature controls: concentrating the crude composition at a temperature below 90°C and separating the intermediate composition at a temperature at or below 35°C (Compl. ¶126).
  • Asserted Claims: At least independent claim 1 (Compl. ¶123).
  • Accused Features: The complaint alleges that Defendants’ Ace-K product is purified using this process, as evidenced by its low level of organic impurities (Compl. ¶128-129).

U.S. Patent No. 10,590,095 - "Acesulfame Potassium Compositions and Processes for Producing Same"

Issued March 17, 2020

  • Technology Synopsis: The ’095 Patent is related to the ’163 Patent and is also directed to removing acetoacetamide impurity during purification. It claims a process with different temperature limitations: concentrating the crude composition at a temperature below 85°C and separating the intermediate composition at a temperature at or below 20°C (Compl. ¶141).
  • Asserted Claims: At least independent claim 1 (Compl. ¶138).
  • Accused Features: The complaint alleges that Defendants’ Ace-K product is purified using this process, as evidenced by its low level of organic impurities (Compl. ¶143-144).

III. The Accused Instrumentality

Product Identification

The accused product is "Jinhe's Ace-K," an acesulfame potassium sweetener manufactured, supplied, and imported by Defendants (Compl. ¶47). The complaint includes a diagram of the molecular structure for the Accused Product (Compl. ¶47).

Functionality and Market Context

The Accused Product is described as a high-purity, calorie-free artificial sweetener used in food, beverage, pharmaceutical, and other applications (Compl. ¶50-51). The complaint alleges that Defendant Jinhe is "the largest producer" of acesulfame potassium in the world and that its food additive products hold a "leading position in the global production capacity and market share" (Compl. ¶16, ¶48). The complaint further alleges that the other defendants import, sell, and distribute Jinhe's Ace-K in the United States (Compl. ¶61, ¶68, ¶70-74).

IV. Analysis of Infringement Allegations

The complaint asserts infringement under 35 U.S.C. § 271(g), alleging that Defendants import, offer to sell, and sell a product in the U.S. that is made by a process patented in the U.S. (Compl. ¶80). The infringement theory is based on an inference that the high purity of the Accused Product could only be achieved at a low cost by using the patented processes (Compl. ¶87).

'546 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a process for producing a finished acesulfame potassium composition... Defendants allegedly use a process to make the Accused Product, acesulfame potassium (Compl. ¶57). ¶57, ¶82 col. 1:14-18
(a) contacting a cyclizing agent and a solvent... (c) forming from the cyclic sulfur trioxide adduct the finished acesulfame potassium composition comprising... less than 35 wppm 5-chloro-acesulfame potassium; The Accused Product is alleged to be a finished acesulfame potassium composition that contains less than 35 wppm of the 5-chloro-acesulfame potassium impurity. Jinhe's product manual allegedly indicates the product has less than 20 wppm of this impurity (Compl. ¶86). ¶85, ¶86 col. 4:5-9
wherein contact time from the beginning of step (a) to the beginning of step (b) is less than 60 minutes. The complaint alleges on information and belief that Defendants use the claimed process, including the sub-60-minute contact time, because it allows for lower-cost production of a high-purity product (Compl. ¶87). ¶82, ¶87 col. 4:40-49

'004 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
(c) reacting an acetoacetamide salt with the cyclizing agent composition... wherein prior to being reacted with the acetoacetamide salt, the cyclizing agent composition has a temperature that is lower than the initial temperature of the cyclizing agent and/or the initial temperature of the solvent; The complaint alleges on information and belief that Defendants use the claimed pre-cooling process step to achieve high purity at a lower cost (Compl. ¶101). ¶96, ¶101 col. 7:46-56
(d) forming from the cyclic sulfur trioxide adduct the finished acesulfame potassium composition comprising... less than 35 wppm 5-chloro-acesulfame potassium; The Accused Product is alleged to contain less than 35 wppm of the 5-chloro-acesulfame potassium impurity. Jinhe's product manual allegedly indicates the product has less than 20 wppm of this impurity (Compl. ¶100). ¶99, ¶100 col. 4:5-9

Identified Points of Contention

  • Evidentiary Questions: The central issue for all asserted patents will likely be one of proof. The complaint infers the use of the patented processes from the chemical characteristics of the final product (i.e., low impurity levels) and alleged economic incentives. A key question will be whether Plaintiff can produce direct evidence that Defendants’ manufacturing and purification processes in China actually practice the specific time, temperature, and cooling limitations required by the claims.
  • Scope Questions: The case raises the question of whether other, non-infringing processes can achieve the same low impurity levels cited in the complaint. The analysis may focus on whether the product specifications for the Accused Product necessarily require the use of the patented methods or if alternative chemical pathways exist.

V. Key Claim Terms for Construction

The Term: "contact time" (from ’546 Patent, claim 1)

  • Context and Importance: The ’546 patent family's novelty is centered on limiting this specific duration to "less than 60 minutes" (or "less than 15 minutes" in the ’098 Patent) to prevent impurity formation. The precise start and end points of this "contact time" in a potentially continuous industrial process will be critical to the infringement analysis.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Narrower Interpretation: The specification provides an explicit definition: "‘Contact time,’ as used herein, refers to the time period that the solvent contacts the cyclizing agent before formation of the cyclic sulfur trioxide adduct... contact time begins when at least some of the solvent contacts at least some the cyclizing agent... and contact time ends when the acetoacetamide salt first contacts the cyclizing agent" (’546 Patent, col. 4:40-49). This language provides a specific, process-based definition that parties may argue is controlling.
    • Evidence for a Broader Interpretation: A party might argue that in a large-scale continuous process, the moments of "first contact" are not discrete points in time, potentially opening the door to arguments about how to measure this period in practice.

The Term: "a temperature that is lower than the initial temperature of the cyclizing agent and/or the initial temperature of the solvent" (from ’004 Patent, claim 1)

  • Context and Importance: This cooling step is a key limitation in the ’004 and ’098 patents. The infringement determination will depend on whether Defendants’ process includes such a relative cooling step and how "initial temperature" is defined and measured.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The plain language of the claim requires only a relative decrease in temperature, not a specific absolute temperature or a specific magnitude of decrease. This could support a reading that any intentional cooling of the composition before reaction meets the limitation.
    • Evidence for a Narrower Interpretation: The specification discusses cooling the cyclizing agent composition to specific temperature ranges, such as "less than 15° C." (’004 Patent, col. 7:58-64). A defendant might argue these embodiments limit the scope of "lower than" to a technologically significant temperature reduction, not a trivial one.

VI. Other Allegations

Indirect Infringement

The complaint alleges inducement of infringement for all five patents. The factual basis is the allegation that Defendant Jinhe, with knowledge of the patents, actively induced its distributors and customers to import and sell the Accused Product, which is made by the patented processes (e.g., Compl. ¶81, ¶95).

Willful Infringement

Willfulness is predicated on Defendants' alleged "actual knowledge of the ['patent'] at least as early as the filing of this complaint" (e.g., Compl. ¶79, ¶93). This allegation supports a claim for willful infringement based on post-suit conduct but does not allege pre-suit knowledge of the patents.

VII. Analyst’s Conclusion: Key Questions for the Case

  • A core issue will be one of evidentiary proof: Can Plaintiff, whose allegations are based on "information and belief," develop sufficient evidence through discovery to prove that Defendants’ overseas manufacturing process literally practices the specific time and temperature control steps recited in the asserted process claims? The case may depend heavily on whether the final product's purity profile can serve as reliable circumstantial evidence of the process used to create it.
  • A second key question will be one of technical necessity: Can Defendants demonstrate that the high purity of their Ace-K product is achievable through alternative, non-infringing manufacturing or purification methods? This would counter Plaintiff's inference that the product could only be made economically by using the patented processes.