Tenax Corp. v. Tensar Corp.

743 F. Supp. 1204, 14 U.S.P.Q. 2d (BNA) 2049, 1990 U.S. Dist. LEXIS 10931, 1990 WL 109209
CourtDistrict Court, D. Maryland
DecidedApril 24, 1990
DocketCiv. H-89-424
StatusPublished
Cited by1 cases

This text of 743 F. Supp. 1204 (Tenax Corp. v. Tensar Corp.) is published on Counsel Stack Legal Research, covering District Court, D. Maryland primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Tenax Corp. v. Tensar Corp., 743 F. Supp. 1204, 14 U.S.P.Q. 2d (BNA) 2049, 1990 U.S. Dist. LEXIS 10931, 1990 WL 109209 (D. Md. 1990).

Opinion

MEMORANDUM AND ORDER

ALEXANDER HARVEY, II, Chief Judge.

Presently before the Court in this patent case is plaintiffs’ motion for partial summary judgment. Plaintiffs are Tenax Corporation (hereinafter “Tenax”), RDB Plasto-tecnica SpA (hereinafter “RDB”) and Mario Beretta (hereinafter “Beretta”). 1 They manufacture and retail a plastic netting product used in civil engineering projects. Plaintiffs have here sued Tensar Corporation (hereinafter “Tensar”), which also produces a competing plastic netting product. Plaintiffs seek a declaratory judgment that their product does not infringe two United States patents, under which Tensar manufactures and sells its product.

Discovery proceedings in this case have been extensive. 2 Supported by a lengthy memorandum of law and voluminous materials, plaintiffs have filed a motion for partial summary judgment, claiming that their product does not infringe the patents because the patents describe a manufacturing process and starting material that differ from plaintiffs’ own process. Alternatively, plaintiffs contend that the patents are invalid under principles of estoppel, obviousness, anticipation and fraud.

Defendant Tensar has opposed the motion and has itself filed lengthy memoranda and numerous exhibits. Both sides have submitted physical samples of the products, and oral argument has been heard in open Court. For the reasons stated herein, plaintiffs’ motion for partial summary judgment will be denied.

I

Background

(a)

The Parties

Tenax is a Maryland corporation with its principal place of business in Jessup, Maryland. Tenax imports into the United States from Italy plastic polymer geogrid products, including its so-called TT-AMP and LBO product series, and Tenax sells these products directly to contractors for use in civil engineering applications. Tenax imports these products from RDB, an Italian corporation which manufactures the prod *1206 ucts at its facilities in Italy. Tenax is a wholly owned subsidiary of RDB. Beretta is an Italian citizen and the chief executive officer of both RDB and Tenax.

Defendant Tensar is a Georgia corporation with its principal place of business in Morrow, Georgia. Tensar manufactures, distributes and sells plastic polymer geo-grid products from its Georgia plant. The Tensar products consist of polymer geogrid products which, like the Tenax products, are used for soil reinforcement and other civil engineering applications.

Tensar is the exclusive licensee of both patents at issue in this case. The owner of the patents is P.L.G. Research Limited (“P.L.G.”), an English patent holding company with its registered office in Lancashire, England. P.L.G. has appointed as its sole licensing agent Netlon Limited (“Net-lon”), an English corporation with its principal place of business in Lancashire, England. Dr. Frank Mercer, the director and principal stockholder of both P.L.G. and Netlon, is the inventor of both patents. The patents are United States Patent No. 4,374,798 (“Mercer ’798”) and United States Patent No. 4,756,946 (“Mercer ’946”).

(b)

The Products

Mercer ’798 (hereinafter the “Process Patent”) entitled “Production of Plastic Mesh Structure,” was issued by the Patent and Trademark Office (hereinafter the “PTO”) to Dr. Frank Brian Mercer on February 22, 1983. Mercer ’946 (hereinafter the “Product Patent”), entitled “Plastic Material Mesh Structure,” was issued to Dr. Mercer on July 12, 1988. Both patents are directed to a method of producing a geo-grid product from a “substantially unipla-nar plastics starting material.”

Geogrid products are netted structures composed of plastic polymers that have a strength which makes them suitable for use in mechanical and civil engineering projects. Uniaxial geogrids consist of a plastic starting material with a regular pattern of holes which, when stretched in one direction, form a strong netting structure ideal for shoring up earth embankments, dams, and retaining walls. Biaxial geo-grids consist of the same starting material that is stretched in two directions at right angles to each other. Biaxial geogrids are used in heavy construction, such as the reinforcement of fill materials under highways or building foundations. Plastic netting material has advantages over a solid sheet of material like steel or concrete, because it is flexible and reduces stress and cracking.

These geogrid structures are made from plastic polymer sheets containing a rectangular pattern of holes. Under the patents, the starting material, which must be at least 0.75 mm thick, is stretched, causing the holes to expand into elongated spaces between solid bars of plastic and forming the netted structure. Difficulties in the manufacturing process arise because of the necessity that the plastic be stretched until the material is molecularly oriented. A product is molecularly oriented when the molecules of the elongated strands have moved, or are oriented into the junctions at the point where they meet the solid bar. This molecular orientation gives the plastic netting its high strength.

(c)

The Manufacturing Processes

Tensar manufactures its product by extruding a melted plastic polymer material as a solid flat sheet of plastic having a uniform thickness. Once it has cooled, the material is then “cold punched” to produce a regular pattern of holes across the plastic sheet. The plastic sheet is heated once again to a temperature below the softening temperature and is then stretched either in one or two directions to produce a plastic netting with the strength of a medium quality steel slab. The stretching results in an orientation of the molecules of the plastic around the junctions.

To produce the Tenax netting material, a melted plastic polymer is extruded through a cylindrical opening to form a circle of plastic material. Attached to the cylindrical opening are two die members which open and close over the melted plastic as it passes through the opening. The die members are cut like teeth to allow some plastic *1207 to flow at all times, while interrupting the flow of some plastic when closed. This interruption of the plastic flow creates the holes in the sheet which, when stretched, will create the netting structure. Once the Tenax plastic material is extruded through the cylinder, it passes over a mandril and is cooled. The plastic cylinder is then cut into a plastic sheet. The sheet is stretched either in one direction to form the uniaxial geogrid or in two directions to form the biaxial geogrid.

It thus appears that the two processes differ in that Tensar cold punches a solid plastic sheet, while Tenax creates the holes by deforming the plastic material around the die teeth during the extrusion process. Tenax contends that this deformation at the time of extrusion causes molten plastic to gather thickly on the edges of the holes and gives the starting material a molecular orientation that differs from the Tensar starting material.

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743 F. Supp. 1204, 14 U.S.P.Q. 2d (BNA) 2049, 1990 U.S. Dist. LEXIS 10931, 1990 WL 109209, Counsel Stack Legal Research, https://law.counselstack.com/opinion/tenax-corp-v-tensar-corp-mdd-1990.