EI Du Pont De Nemours v. Phillips Pet. Co.

• Decision Date: 26 February 1987
• Docket Number: Civ. A. No. 81-508-JLL.
• Citation: 656 F. Supp. 1343
• Parties: E.I. DU PONT DE NEMOURS & COMPANY, Plaintiff, v. PHILLIPS PETROLEUM COMPANY, Phillips 66 Company, and Phillips Driscopipe, Inc., Defendants.
• Court: U.S. District Court — District of Delaware

656 F. Supp. 1343

E.I. DU PONT DE NEMOURS & COMPANY, Plaintiff, v. PHILLIPS PETROLEUM COMPANY, Phillips 66 Company, and Phillips Driscopipe, Inc., Defendants.

Civ. A. No. 81-508-JLL.

United States District Court, D. Delaware.

February 26, 1987.

COPYRIGHT MATERIAL OMITTED

COPYRIGHT MATERIAL OMITTED

William O. LaMotte III of Morris, Nichols, Arsht & Tunnell, Wilmington, Del., and John O. Tramontine, Edward F. Mullowney, Glenn A. Ousterhout, and Thomas J. Vetter of Fish & Neave, New York City, for plaintiff.

C. Waggaman Berl, Jr., Wilmington, Del., and Harry J. Roper, Sidney Neuman, George S. Bosy, Nicholas A. Poulos, Lawrence E. Apolzon, Susan Bennett Fentress, Raymond N. Nimrod, and Steven R. Trybus of Neuman, Williams, Anderson & Olson, Chicago, Ill., for defendants.

OPINION

LATCHUM, Senior District Judge.

I. INTRODUCTION

This is a patent infringement suit¹ in which the plaintiff, E.I. duPont de Nemours and Company ("DuPont"), has charged the defendants, Phillips Petroleum Company, Phillips Chemical Company, whose name was changed during the pendency of this case to Phillips 66 Company, and Phillips Driscopipe, Inc., with the infringement of Claims 1, 2, 5, 10, 12, and 14 of DuPont's U.S. Patent No. 4,076,698 ("the '698 patent"). (Docket Item "D.I." 212 at 1.) Since Phillips Chemical Company, now named Phillips 66 Company, and Phillips Driscopipe, Inc., are wholly owned Delaware corporate subsidiaries of Phillips Petroleum Company, all three defendants will be referred to collectively as "Phillips." (D.I. 212 at 1 and 252.) Phillips' Answer, Affirmative Defenses, and Counterclaims allege that the '698 patent is invalid and unenforceable for various reasons and there has been no infringement. (D.I. 159.) In addition, Phillips filed a pretrial motion for summary judgment to dismiss DuPont's suit under the doctrine of collateral estoppel based on a rejection of all the claims of the '698 patent by a Patent Examiner entered in a reissue-reexamination proceeding in the Patent Office. (D.I. 210.) The Court reserved decision on the summary judgment motion until after trial. The parties stipulated with Court approval that the liability issues of validity, enforceability, and infringement would be bifurcated from the trial of the damage issues. (D.I. 161.)

The case was tried on the liability issues to the Court without a jury from July 21, 1986 through August 18, 1986.² After carefully considering the sufficiency, weight, and credibility of the testimony of the witnesses, their demeanor on the stand, the documentary evidence admitted at trial, and the post-trial submissions of the parties, the Court enters the following findings of fact and conclusions of law which are embodied in this opinion as permitted by Rule 52(a), Fed.R.Civ.P.

II. THE FACTS

A. The Invention In Issue

The '698 patent in suit relates to copolymers of ethylene and higher alpha-olefins. The original patent application was filed on March 1, 1956; a continuation-in-part application was filed on January 4, 1957, and the patent issued on February 28, 1978 (PX 1).³

The invention of the patent is based on DuPont's discovery that the "impact strength" and the "environmental stress crack resistance" of melt processable ethylene copolymers can be unexpectedly improved by incorporating a higher alpha-olefin comonomer having five or more carbon atoms (Tr. 87-93). The '698 patent specifically discloses that the alpha-olefin comonomers which are "most outstanding in producing resins with high impact strength and excellent stress crack resistance" are those having "preferably 5 to 18 carbon atoms per molecule" (PX 1, col. 3, 11. 19-23).

There are two aspects to the '698 patent: (1) the composition of the ethylene copolymers, and (2) the superior impact strength and the superior environmental stress crack resistance that can be obtained by using those ethylene copolymers.

1. The Composition of the Ethylene Copolymers

Polymers are large molecules made by chemically joining together many small molecules called monomers. Polyethylene is the polymer made by polymerizing ethylene monomer:

ETHYLENE⁴ — C = C POLYETHYLENE — ...-C-C-C-C-C-C-C-C- ...

(PX 1200; Tr. 36-37)

There are two types of polyethylenes. The first, free-radical polyethylene, was developed in the 1930's (Tr. 1180), and was commercialized after the end of World War II (Tr. 52). Free-radical polyethylene is formed by highly reactive growing molecules containing free radicals. The polymer molecules formed by this process have both long and short chain branches. The structure can be analogized to a rose bush (Tr. 37-41).

The second type of polyethylene is linear polyethylene made by coordination catalyst processes developed in the 1950's (Tr. 61-62; 1181). Linear polyethylene molecules are long straight chain structures. These molecules do not have the branches that free-radical polyethylene molecules have (Tr. 62).

Copolymers are made by polymerizing two monomers (Tr. 66). For example, when ethylene and hexene are copolymerized, an ethylene-hexene copolymer is formed.

(PX 1202; Tr. 64-67)

Hexene (or hexene-1) is a six carbon "alpha-olefin." It has a double bond at one end of the molecule. Its structure, and the structures of other typical alpha-olefin comonomers are as follows:

(PX 1203; Tr. 67-68)

The compositions described in the '698 patent are linear copolymers of ethylene and higher alpha-olefin comonomers (PX 1, col. 1, 1. 61 to col. 2, 1. 23; Tr. 67-68). The higher alpha-olefin comonomers begin with pentene which has 5 carbon atoms, and include hexene (6 carbon atoms), heptene (7 carbon atoms), octene (8 carbon atoms), and the remaining higher alpha-olefins through octadecene, which has 18 carbon atoms (Tr. 67). DuPont uses octene-1 in its commercial ethylene copolymers and has in some instances used decene (Tr. 1090-91). Phillips uses hexene-1 (PX 1237; Tr. 2275; 3161-62; 3168-69; 3206; 3212-13).

Copolymers made with the lower alpha-olefins, such as butene (4 carbon atoms) and propylene (3 carbon atoms), are not within the scope of the invention. The '698 patent specifically discloses that in "producing resins with high impact strength and excellent stress crack resistance ... propylene is not effective; butene-1 shows only marginal effectiveness in this respect" (PX 1, col. 3, 11. 19-25; Tr. 110-11).

The ethylene copolymers of the '698 patent can be processed in conventional melt processing equipment (Tr. 88). Melt index is a measure of the rate at which the copolymer flows when melted and relates to the melt processability of the material. The patent specifically discloses that the ethylene copolymers of the '698 patent "have melt indexes in the range of 0.2 to 20" to enable them "to be fabricated by conventional fabricating techniques" (PX 1, col. 4, 11. 12-15).

The ethylene-higher alpha-olefin copolymers of the invention are characterized by several parameters so that they can be distinguished by external tests from linear ethylene homopolymers and from linear ethylene copolymers that are rubber-like (Tr. 856, 858-60, 888-89). Those parameters are measurements of comonomer content, density, and percent crystallinity.

Comonomer content is a measurement of the presence and amount of comonomer in the ethylene-higher alpha-olefin copolymer which aids in distinguishing the copolymers of the invention from linear ethylene homopolymers and linear ethylene copolymers that are rubber-like. The '698 patent discloses that the amount of higher alpha-olefin can vary from a very small amount of comonomer (linear ethylene homopolymer has none) on the order of 1% by weight up to about 20% by weight (above 20% the copolymers become rubber-like) (Tr. 139, 859-60, 888-89).

The measurement technique for comonomer content disclosed in the patent is infrared spectroscopy (PX 1, col. 7, 11. 62-64 and Table I; Tr. 363-64, 380-90). Infrared spectroscopy comonomer content measurements as low as 1.4% by weight for a heptene (7 carbon) polymer and 1% by weight for a decene (10 carbon) copolymer (PX 1, Table I Example 1 and col. 7, 11. 62-64) are reported. When the '698 patent application was filed in the mid-1950's, the margin of error for infrared comonomer content measurements was much greater than the degree of accuracy that can be obtained today by much later developed techniques. For example, with a hexene copolymer, the margin of error was at the very least ± 0.6%. Thus, a nominal infrared measurement of 1% by weight for hexene comonomer would have included copolymers with hexene comonomer contents ranging from about 0.4% to about 1.6% by weight (Tr. 3616).

Density and degree of crystallinity are also indications of the amount of comonomer, aiding to distinguish the copolymers of the invention from linear ethylene homopolymers and linear ethylene copolymers that are rubber-like. As comonomer is incorporated in the linear polyethylene chain, both the density and degree of crystallinity decrease from the values measured with linear polyethylene homopolymer alone (Tr. 132). The density data that are included in the '698 patent disclose that small amounts of comonomer can be used. Specifically, the patent discloses that with the materials the DuPont researchers were using, for linear polyethylene homopolymers the densities ranged from 0.945 to 0.960, and that as comonomer was added, the density decreased. Similarly, the patent discloses that the degree of crystallinity likewise decreased as comonomer was added (Tr. 132).

2. Superior Impact Strength And Environmental Stress Crack Resistance Obtained With Higher Alpha-Olefin Copolymers

The invention of the '698 patent was not the discovery that ethylene could be copolymerized with higher alpha-olefins, nor was it the discovery of a new comonomer content range, a new density range, or a new X-ray crystallinity range (Tr. 135, 607-08). The invention was the discovery that melt processable copolymers of ethylene and higher...