Shield Pack LLC v. CDF Corp

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Shield Pack, LLC ( Delaware)
  • Defendant: CDF Corporation (Massachusetts)
  • Plaintiff’s Counsel: Davenport, Files & Kelly; K&L Gates LLP
• Case Identification: 3:10-cv-00048, W.D. La., 11/10/2010
• Venue Allegations: Venue is alleged based on Defendant doing business within the judicial district and the events giving rise to the action occurring there.
• Core Dispute: Plaintiff seeks a declaratory judgment that two of Defendant’s patents related to flexible liners for bulk containers are invalid and not infringed by Plaintiff's products.
• Technical Context: The technology concerns the design of flexible liners used in "bag-in-box" and Flexible Intermediate Bulk Container (FIBC) systems for storing and transporting liquids or other flowable materials.
• Key Procedural History: The action arises from a prior patent infringement suit filed by Defendant CDF against Plaintiff Shield Pack in the District of Massachusetts concerning the ’121 Patent, which CDF later voluntarily dismissed without prejudice. The complaint also notes that CDF has alleged infringement of the ’711 Patent in its First Amended Counterclaims filed within the current action, establishing a justiciable controversy for both patents.

Case Timeline

Date	Event
1994-11-18	U.S. Patent No. 5,788,121 Priority Date
1998-08-04	U.S. Patent No. 5,788,121 Issue Date
2004-07-27	U.S. Patent No. 7,798,711 Priority Date
2009-05-15	CDF files Massachusetts Action against Shield Pack re: '121 Patent
2009-09-10	CDF voluntarily dismisses Massachusetts Action
2010-09-21	U.S. Patent No. 7,798,711 Issue Date
2010-10-27	CDF alleges infringement of '711 Patent in counterclaims
2010-11-10	Complaint Filing Date (First Amended Complaint)

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

U.S. Patent No. 5,788,121 - "Bag for Bag-in-Box and Bag-in-Box," issued August 4, 1998

The Invention Explained

• Problem Addressed: The patent's background section describes issues with conventional flat plastic inner bags used in bag-in-box systems. These bags often fail to conform to the rigid outer box, creating "dead space" that can lead to the inner bag moving, rubbing, and breaking. This poor fit also results in crumpled corners where liquid can become trapped, preventing complete discharge of the contents (’121 Patent, col. 1:59-2:16).
• The Patented Solution: The invention is a four-side-seal bag designed to form a shape closely resembling a cube or rectangular parallelepiped when filled. This is achieved through a specific construction at the bag's corners, which feature "oblique seal portions" and "triangular fin portions." These seals effectively isolate the corners from the main product-holding area, allowing the bag to fill out the outer box more completely, improving stability and discharge efficiency (’121 Patent, Abstract; col. 4:4-28). The bag body is composed of opposing front, back, and folded side portions made of superposed synthetic resin films (’121 Patent, col. 4:4-14).
• Technical Importance: This design sought to enhance the reliability and efficiency of bulk liquid containers by creating a liner that fits better within standardized outer boxes, thereby reducing product waste and increasing durability during shipping and handling (’121 Patent, col. 2:42-57).

Key Claims at a Glance

• The complaint seeks a declaratory judgment of non-infringement for all claims but does not specify which claims CDF has asserted. Independent claim 1 is representative.
• Essential elements of independent claim 1 include:
  • A four-side-seal type bag body composed of a pair of opposing flat portions and two inwardly folded side portions.
  • Oblique seal portions at the respective corner portions of the bag body.
  • Triangular fin portions formed at the respective corner portions.
  • The flat and side portions are composed of at least two sheets of synthetic resin films superposed in a non-bonded state.
  • The oblique seal portion is formed by bonding inner surfaces of the bag body to obliquely connect a top/bottom seal portion to a side seal portion.
  • The triangular fin portion is defined by being enclosed by the side seal, the oblique seal, and a top or bottom seal portion.
• The complaint does not limit its non-infringement request to specific claims, implicitly reserving the right to contest any asserted dependent claims as well (Compl. ¶27).

U.S. Patent No. 7,798,711 - "Flexible Liner for FIBC or Bag-in-Box Container Systems," issued September 21, 2010

The Invention Explained

• Problem Addressed: The patent identifies difficulties in filling and completely emptying large flexible liners, especially those containing viscous liquids. The liner has a tendency to collapse, trapping contents, and the liner bottom often does not slope toward the drain fitting, causing product to pool (’711 Patent, col. 2:35-55).
• The Patented Solution: The invention provides a collapsible liner with integrated tabs that extend from the liner panels. These tabs include an "attachment feature"—such as a strip of tape, a reinforced hole, or a fabric strip—that allows the liner to be secured to the outer container. This support helps prevent the liner from collapsing during filling or emptying. The tabs can also be engaged by a winder system to progressively lift and squeeze the liner, facilitating a more complete discharge of its contents (’711 Patent, Abstract; col. 6:1-17).
• Technical Importance: The invention offers a method to better secure and manage large flexible liners within bulk containers, which improves the efficiency of bulk material handling by minimizing liner collapse and reducing product waste (’711 Patent, col. 2:50-55).

Key Claims at a Glance

• The complaint seeks a declaratory judgment of non-infringement for all claims but does not specify which claims CDF has asserted. Independent claim 1 is representative.
• Essential elements of independent claim 1 include:
  • A liner comprising first and second flexible panels joined by first, second, and third seals, with the second seal being oblique to the first.
  • The panels extend across the oblique second seal to form a triangular fin portion.
  • The triangular fin portion comprises a tab defined by a "series of perforations," allowing the tab to be at least partially separable from the remainder of the fin.
  • The tab comprises an "attachment feature" adapted to facilitate its attachment to a bulk container.
• The complaint does not limit its non-infringement request to specific claims, implicitly reserving the right to contest any asserted dependent claims (Compl. ¶31).

III. The Accused Instrumentality

Product Identification

The complaint identifies the accused products generally as "intermediate bulk packaging liners" sold under the "Shield Pack's products" designation (Compl. ¶7).

Functionality and Market Context

The complaint alleges that Shield Pack has been in the business of designing, developing, and selling these liners since 1968 (Compl. ¶7). It further states that Defendant CDF's products, some of which are allegedly covered by the patents-in-suit, compete with Shield Pack's products (Compl. ¶¶ 12-13). The complaint does not provide specific technical details, model numbers, or marketing materials for the accused liners.

IV. Analysis of Infringement Allegations

The complaint does not contain specific infringement allegations, claim charts, or a narrative infringement theory. It is a declaratory judgment action seeking a ruling of non-infringement in response to allegations made by Defendant CDF in a prior lawsuit and in counterclaims in the present action (Compl. ¶¶ 14, 22). Therefore, a complaint does not provide sufficient detail for analysis of infringement allegations.

No probative visual evidence provided in complaint.

V. Key Claim Terms for Construction

'121 Patent

• The Term: "oblique seal portions"
• Context and Importance: The shape, location, and function of these seals are central to the claimed invention, which distinguishes itself from prior art flat bags by its specific corner construction. The outcome of the infringement analysis will likely depend on whether the seals on Shield Pack's liners meet the structural and functional definition of this term as used in the patent.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The patent describes the term functionally as a seal that "obliquely connect[s] the top or bottom seal portion and the side seal portion" and has a "straight band-shape" (’121 Patent, col. 4:16-25). A party might argue that any angled, band-shaped seal performing this connection falls within the scope of the claim.
  • Evidence for a Narrower Interpretation: The specification discloses specific preferred angle ranges, such as 40-50 degrees between the bottom seal and the oblique seal, and 45-55 degrees for the top seal (’121 Patent, col. 8:1-8). A party could argue that the term should be limited to seals falling within or near these disclosed angular ranges, which are presented as yielding an "excellent conforming property."

'711 Patent

• The Term: "a tab defined in less than a whole portion of the triangular fin portion by a series of perforations"
• Context and Importance: This limitation describes the core structural innovation of the '711 Patent: a separable tab integrated into the liner's corner structure. Infringement will turn on whether Shield Pack's liners have a feature that meets this multi-part definition, requiring a specific relationship between a tab, a fin, and perforations.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: A party might argue that "series of perforations" should be construed broadly to include any line of weakening, such as a score line or a thinned section, that allows a portion of the fin to be separated and function as a tab.
  • Evidence for a Narrower Interpretation: The specification explicitly illustrates the tab (2) being defined by an "L-shaped perforated boarder 70" that allows it to be separated from the top flap (’711 Patent, Fig. 5a; col. 11:10-14). Practitioners may focus on this term because a defendant could argue that "series of perforations" requires discrete, spaced-apart holes and that the tab must be created from a pre-existing "triangular fin portion," not from another part of the liner.

VI. Other Allegations

• Indirect Infringement: The complaint does not provide sufficient detail for analysis of indirect infringement. While the prayer for relief requests a declaration that Shield Pack and its customers have not infringed, the complaint body does not set forth any specific facts related to inducement or contributory infringement theories (Compl., WHEREFORE ¶B, E).
• Willful Infringement: This section is not applicable. As a declaratory judgment action filed by the accused infringer, the complaint does not contain allegations of willful infringement.

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

• A primary issue will be one of claim construction and structural equivalence: For the ’121 Patent, can the terms "oblique seal portion" and "triangular fin portion" be construed to read on the geometry of Shield Pack's liners? For the ’711 Patent, do the accused products incorporate the highly specific structure of a "tab defined in less than a whole portion of the triangular fin portion by a series of perforations," or is there a fundamental structural difference that places them outside the claim scope?
• A key evidentiary question will be whether CDF, as the patentee, can produce sufficient evidence to map the features of Shield Pack's actual products to each limitation of the asserted claims. As this case proceeds, the burden will fall on CDF to substantiate the infringement allegations that gave rise to this declaratory judgment action.
• A central question regarding validity will be whether Shield Pack can present prior art or other evidence sufficient to prove, by clear and convincing evidence, that the claimed inventions in the ’121 and ’711 patents are invalid as anticipated, obvious, or failing to meet the requirements of enablement and written description under 35 U.S.C. § 112.