Afros SpA v. Krauss-Maffei Corp.

• Citation: 671 F. Supp. 1402
• Decision Date: 17 August 1987
• Docket Number: Civ. A. No. 84-358 MMS.
• Parties: AFROS S.P.A., Plaintiff, v. KRAUSS-MAFFEI CORPORATION, Defendant.
• Court: U.S. District Court — District of Delaware

671 F. Supp. 1402

AFROS S.P.A., Plaintiff, v. KRAUSS-MAFFEI CORPORATION, Defendant.

Civ. A. No. 84-358 MMS.

United States District Court, D. Delaware.

August 17, 1987.

COPYRIGHT MATERIAL OMITTED

John G. Mulford, of Theisen, Lank, Mulford & Goldberg, P.A., Wilmington, Del. (Carl G. Love, William K. West, Jr., Esq., and Peter W. Gowdey, of Cushman, Darby & Cushman, Washington, D.C., of counsel), for plaintiff.

William D. Bailey, Jr., of Bayard, Handelman and Murdoch, P.A., Wilmington, Del. (Robert J. Koch, and James W. Hellwege, Alexandria, Va., of counsel), for defendant.

OPINION

MURRAY M. SCHWARTZ, Chief Judge.

Plaintiff Afros, S.p.A. ("Afros") has sued Krauss-Maffei Corporation ("KMC") for infringement of its United States Letters Patent No. 4,332,335 ("'335 Patent"). KMC, a wholly-owned subsidiary of Krauss-Maffei Aktiengesellschaft ("KMAG"), denies any infringement and counterclaims for infringement by Afros of its United States Patents No. 3,706,515 ("'515 Patent") and No. 3,975,128 ("'128 Patent"). All three patents relate to high-pressure impingement mixing used to produce polyurethane products. The parties manufacture or distribute mixing heads for use in both open and closed pour molds.

The Court conducted a nine-day trial on liability issues that concluded on February 27, 1987. By the parties' consent, the damages issue has been reserved for a later proceeding. Post-trial argument occurred on April 29 after the filing of proposed findings of fact and briefs. After careful consideration of the sufficiency, weight, and credibility of the witnesses' testimony, their demeanor on the stand, documentary evidence admitted at trial, and the parties' post-trial submissions, the following constitutes the Court's factual and legal conclusions in accordance with Federal Rule of Civil Procedure 52(a). Because the parties each allege infringement of its patents, the Court considers those issues separately.

The Court holds the '335 Patent valid and literally infringed by KMC's mixing heads. Defendant's infringement is also willful under 35 U.S.C. § 284, and an exceptional case under 35 U.S.C. § 285. On the counterclaim, the Court holds the assignment of the '515 and '128 Patent rights between KMAG and KMC ineffective to grant KMC standing to bring the counterclaim. In the alternative, the Court holds the two patents are valid but not infringed.

I. BACKGROUND

Oversimplified, flexible foam polyurethane produced by the mixing heads of the parties are the result of a process whereby two polymers are mixed together and deposited in a mold in which they harden to produce the desired item with the correct shape and weight.¹ The mixing procedure, called impingement mixing, takes place in a mixing head.² Trial Transcript ("Tr.") 86. The two materials used to form polyurethane, polyol³ and isocyanate, must be throughly mixed if the product is to be acceptable. Tr. 85. Polymerization begins when the chemicals first interact, but the completion of the process takes varying amounts of time depending on the exact polymers being impinged.

The mixing process requires atomization of the components in a narrow area, where a high degree of turbulence is generated. Tr. 59. The components are delivered under high-pressure, usually at about 200 atmospheres or "bars," Tr. 68, and reach the mixing chamber through ports in the mixing chamber. The mechanism through which the polyol and isocyanate enter the impingement zone is variously called "infeed ducts," "transfer ports," and "inlet nozzles." For the purposes of this opinion, the Court will use the term inlet nozzles to describe the apparatus for delivering components to the mixing chamber. An external pump maintains the necessary pressure during periods of impingement and recirculation. Tr. 158.

KMAG and Afros manufacture mixing heads which are similar in most respects. Both the Afros heads, designated "FPL," and KMAG's, designated "UL,"⁴ are L-shape. The L-shape design entails a mixing chamber connected at a 90° angle to a discharge or quieting chamber. The polyurethane flows from the discharge chamber into the mold. The chambers are circular, with the length and diameter of the discharge chamber greater than the mixing chamber. PX 151. The key issue in the design of these competing heads is the closeness of the component inlet nozzles to the discharge chamber in an L-shape head. Under the '335 Patent, the location of those nozzles is to be "close to" or "in close proximity to" the quieting chamber. PX 1. According to Dr. Carlo Fiorentini, inventor of the '335 Patent device, locating the inlet nozzles close to the discharge chamber permits additional mixing in the component flow as it exits the mixing chamber and the residual kinetic energy causes a rebounding effect off the opposite wall of the discharge chamber because of the L-shape configuration of the chambers. Tr. 187-88.

The L-shape heads are the product of nearly a decade of research and development in the Reaction Injection Molding ("RIM" industry. In order to achieve good mixing of the polyol and isocyanate, which have an affinity for one another akin to oil and water, the industry moved toward high-pressure mixing heads in the 1970's. Tr. 1554. Unlike low-pressure heads, high-pressure devices mix the chemicals outside the product mold and then pour the polyurethane directly into it. One problem the industry faced was how to maintain the necessary degree of pressure when the components were not being impinged. The defendant's '515 Patent, which has recirculation grooves carved into the sides of the mixing piston, permits the maintenance of high-pressure in the inlet nozzles whether or not the mixing head is in operation. Tr. 1552-53. When the mixing piston is in a closed position, the recirculation grooves direct the components back through the pump system into a storage area. The pump maintains the requisite pressure for impingement mixing until the piston is retracted and the inlet nozzles are unobstructed. The use of recirculation grooves was an important step in the development of the mixing heads at issue in this litigation. See Tr. 1552.

The essential principles for RIM have not changed radically since the early 1970's. According to defendant's expert, Dr. Christopher Macosko, the key concepts for high-pressure mixing heads are:

1) High velocity recirculation.

2) Controlling the duration of the mixing and pouring of the fluid.

3) A retractable plunger to clean the chamber that both permits recirculation and terminates impingement.

4) Creating sufficient back pressure in the mixing chamber both to increase mixing efficiency and eliminate air bubbles in the fluid.

Tr. 1550, 1553, 1555. The central element in the head is the mixing piston, also called a "control slide." The piston has two positions, and its movement is controlled by means of a hydraulic pump system. In the forward or closed position, the chemicals recirculate under high-pressure through the recirculation grooves in the piston. When the piston is retracted, in which position the head is "open," it no longer blocks the inlet nozzles and the chemicals discharge into the mixing chamber. The inlet nozzles for the chemicals are positioned opposite each other and, once the head is open, the chemicals will impinge and form a flow that will be deposited into the mold. At the point of impingement, the highly turbulent flow created in the mixing head permits the polyol and isocyanate to continue to mix after the point of impingement. The length of time in which the head is open, called the "shot," depends on the volume necessary to form the product. Tr. 85. It can last from a few seconds up to half a minute. After the shot, the mixing piston moves forward to both clean the mixing chamber, by forcing any residual matter into the discharge chamber, and recirculates the chemicals.

The discharge chamber, placed at a 90° angle to the mixing chamber, is similarly equipped with a retractable plunger called the cleaning piston. When the shot begins, the cleaning piston will be fully withdrawn, permitting a continuous flow of material out of the mixing chamber into the discharge chamber. Once the mixing piston advances to close the chamber, the cleaning piston will move down to expel any remaining polyurethane. The face of the mixing piston is curved to permit the two pistons to be closed at the same time.

The advantage of high-pressure mix heads is more efficacious mixing than in low-pressure systems. Tr. 1550. The degree of mixing achieved in high-pressure heads will vary, however, depending on a number of factors. There are three major problems to be overcome in constructing a workable high-pressure mixing head: 1) cleaning the mixing and discharge chambers; 2) minimizing what has variously been termed the transient phenomenon or lead-lag problem; 3) creating a good mix while allowing the flow to become laminar, or quieted, at the point of discharge into the mold.

Cleaning the Head: Polyol and isocyanate are highly reactive components that begin their chemical reaction upon impingement to form polyurethane. The length of the polymerization will depend on the particular polyol used. Any residual liquid in the chamber will harden, impeding the movement of the piston and degrading the quality of later shots. The chamber through which chemicals flow must be thoroughly cleaned, otherwise a gluing effect occurs in the head. The face of the mixing piston can serve this function when it is moved into the closed position if it is highly precisioned, leaving no space between the piston face and the chamber walls for polyurethane to accumulate. The cleaning process can also be achieved through sealing grooves on the outer edge of the piston that allow a small amount of polyurethane to form and thereby close off the space between the piston and the wall of the mixing chamber. Tr. 1461; see infra, text at 1434-1435. In L-shape heads, which have two chambers at...