The opinion of the court was delivered by: McAVOY, Chief Judge.
MEMORANDUM-DECISION & ORDER
Plaintiff The Dow Chemical Company ("Dow") brings this action
for patent infringement pursuant to 35 U.S.C. § 271 against
defendant Astro-Valcour, Inc. ("AVI"). Presently before the Court
are AVI's motions for the construction of various claim terms in
Both Dow and AVI manufacture and sell plastic packaging
materials, including plastic foam. Plastic foam is made by mixing
a polymer resin with a blowing agent and other additives. The
mixture is melted and blended in a pressurized environment before
the mixture is pushed through a die into the non-pressurized
atmosphere where it expands. The plastic foam is then allowed to
cure such that the hot plastic cools and hardens.
A blowing agent is a chemical that produces a superatmospheric
pressure inside the cells of the polymer, causing its individual
cells to grow. The principal purpose of the blowing agent is to
bring about the formation and inflation of the cells that
comprise the plastic foam. For years, manufacturers of plastic
foam used chlorofluorocarbon ("CFC") blowing agents. Recently,
however, concern over the impact of CFCs on the earth's ozone
layer has caused foam manufacturers to replace CFC blowing agents
with hydrocarbon and other blowing agents. Although the use of
these alternative blowing agents has reduced or eliminated the
problems associated with the use of CFCs, they present their own
One problem associated with blowing agents is that they diffuse
out of the foam too quickly during the aging period, causing the
foam to experience unacceptable shrinkage. Specifically, once the
foam is formed, the gaseous blowing agent begins to permeate out
of the foam, and air begins to permeate in. If the blowing agent
permeates out more quickly that the air permeates in, the foam
can shrink because the pressure inside the cells of the foam
become less than the atmospheric pressure. Thus, manufacturers
have attempted to find a blowing agent that can form and inflate
the cells of the plastic foam, yet which also exhibits a high
degree of dimensional stability with minimal shrinkage during
aging. A stability control agent helps to control this shrinkage
by slowing the rate of release of the blowing agent from the foam
until air can permeate into the foam to balance the pressure
inside the foam's cells.
Dow owns five patents related to the manufacture of plastic
foam. In the first set of patents, there are three related
patents directed to the use of isobutane as a blowing agent in
creating foam structures: U.S. Patent No. 4,640,933 ("the '933
patent"), U.S. Patent No. 4,694,027 ("the '027 patent"), and U.S.
Patent No. 4,663,361 ("the '361 patent") (collectively, the
"isobutane patents"). The isobutane patents derive from the
original application filed on December 24, 1985, and each
describes an invention comprising three elements: (1) an olefin
polymer resin, (2) a stability control agent, and (3) a blowing
agent consisting of isobutant or certain mixtures of isobutane
and other blowing agents. Specifically, the '933 patent, which
issued on February 3, 1987, describes the foam made with those
elements; the '361 patent, which issued on May 5, 1987, describes
a foamable polymer composition for making foam using those
elements; and the '027 patent, which issued on September 15,
1987, describes the process for making foam with those elements.
In the second set of patents, there are two related patents
directed to the perforation of plastic foam: U.S. Patent No.
5,424,016 ("the '016 patent"), and U.S. Patent No. 5,585,058
("the '058 patent") (collectively, the "perforation patents").
The perforation patents cover a method of accelerating the
release of a blowing agent from plastic foam. The purpose of
perforation is to create channels in the foam to allow the
blowing agent to escape more readily to the outside atmosphere
than if the blowing agent was forced to permeate only through the
cell walls of the plastic foam.
On September 21, 1995, Dow commenced this action against AVI,
the infringement of its isobutane and perforation patents. AVI
now moves for the construction of various claim terms in the
patents. Specifically, with respect to the isobutane patents, it
seeks the construction of the terms (1) "polyolefin foam,"
"polymeric composition" and "olefin polymer foam." As to the
perforation patents, it seeks the construction of the terms (2)
"plastic foam" and "polyethylene foam," (3) "accelerated
release," (4) "perforating," and (5) "extruded." On November 9,
1998, a Markman Hearing*fn1 was held at which the parties
presented oral argument on the construction of the disputed claim
terms and background expert testimony relating to the
manufacturing process of plastic foam. The following discussion
contains the Court's construction of the disputed claim terms.
A. Standard for Claim Construction
A patent infringement analysis involves two steps: first, a
court determines the scope and meaning of a patent claim; and
second, the construed claim is compared to the allegedly
infringing product or process. Markman, 517 U.S. at 390, 116
S.Ct. 1384; Cybor Corp. v. FAS Technologies, Inc.,
138 F.3d 1448, 1454 (Fed.Cir. 1998) (en banc). The first step presents a
question of law exclusively for the court; the second step a
question of fact generally for the jury. Markman, 517 U.S. at
390, 116 S.Ct. 1384; Intervet Am., Inc. v. Kee-Vet Labs., Inc.,
887 F.2d 1050, 1053 (Fed.Cir. 1989).
In determining the scope of a claim, the starting point is the
claim language. See Comark Communications, Inc. v. Harris
Corp., 156 F.3d 1182, 1186 (Fed.Cir. 1998); Fromson v. Advance
Offset Plate, Inc., 720 F.2d 1565, 1571 (Fed. Cir. 1983); see
also Lindemann Maschinenfabrik GMBH v. American Hoist and Derrick
Co., 730 F.2d 1452, 1459 (Fed.Cir. 1984). The claim language
should be construed in context, however, and the other claims,
the patent specification and the prosecution history must be
considered in determining what the claim means. See, e.g.,
Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582
(Fed.Cir. 1996); SRI Int'l v. Matsushita Elec. Corp.,
775 F.2d 1107 (Fed.Cir. 1985).
With respect to the isobutane patents, AVI seeks the
construction of the claim terms "polyolefin foam" in the '933
patent, "polymeric composition" in the '361 patent and "olefin
polymer foam" in the '027 patent. As these terms are not
meaningfully different for purposes of construction, I ...