Specialty Composites v. Cabot Corp.

• Decision Date: 27 April 1988
• Docket Number: Nos. 87-1456,87-1457,s. 87-1456
• Citation: 6 USPQ2d 1601,845 F.2d 981
• Parties: , 6 U.S.P.Q.2d 1601 SPECIALTY COMPOSITES, Plaintiff/Cross-Appellant, v. CABOT CORP., Defendant/Appellant.
• Court: U.S. Court of Appeals — Federal Circuit

Page 981

845 F.2d 981

56 USLW 2663, 6 U.S.P.Q.2d 1601

SPECIALTY COMPOSITES, Plaintiff/Cross-Appellant, v. CABOT CORP., Defendant/Appellant.

Nos. 87-1456, 87-1457.

United States Court of Appeals, Federal Circuit.

April 27, 1988.

Rudolf E. Hutz, Connolly, Bove, Lodge & Hutz, Wilmington, Del., argued for plaintiff/cross-appellant. With him on the brief were James M. Mulligan, Jr., Harold Pezzner and Mary W. Bourke. Also on the brief was Ansel B. Chaplin, Chaplin & Milstein, Boston, Mass., of counsel.

Harold Hestnes, Hale & Dorr, Boston, Mass., argued for defendant/appellant. With him on the brief was Thomas N. O'Connor. Also on the brief were Eugene F. Buell and Lynn J. Alstadt, Buell, Ziesenheim, Beck & Alstadt, Pittsburgh, Pa., and Jack Schuman, Indianapolis, Ind., of counsel.

Before MARKEY, Chief Judge, DAVIS, Circuit Judge, and NICHOLS, Senior Circuit Judge.

DAVIS, Circuit Judge.

Cabot Corporation's (Cabot) United States Patent No. Re. 29,487 ('487 patent) claims certain plastic foam earplugs used for hearing protection. Specialty Composites (Specialty) brought an action in the United States District Court for the District of Massachusetts seeking a declaratory judgment that the '487 patent is invalid, unenforceable, and not infringed by the polyurethane foam earplugs manufactured and sold by Specialty. Cabot counterclaimed for infringement. After a bench trial, the court ruled that Specialty had failed to establish that Cabot's patent is invalid for obviousness under 35 U.S.C. Sec. 103 or unenforceable for inequitable conduct during procurement. However, the court found that Specialty's earplug products do not infringe. ¹ On appeal and cross-appeal, we reverse the decision of noninfringement and affirm the holdings of nonobviousness and enforceability.

I. Background

The invention is a type of earplug used to protect the ear from excessive noise. In 1971 Ross Gardner, an employee of Cabot ², discovered that superior protective earplugs could be made from slow recovery plastic foams. When these polymeric foams are compressed they rebound to their original shape relatively slowly. If earplugs made of slow recovery foams are squeezed to a diameter smaller than the ear canal and inserted into the ear, they recover towards their original shape over a period of several seconds and seal the ear canal. Compared to other hearing protection devices then available, these earplugs had the advantage of a universal fit, comfort, convenience and effective noise attenuation.

Gardner found that it was necessary to select a foam with a composition that imparted mechanical properties falling within certain ranges. If the foam rebounded too quickly the earplugs were difficult to insert; if the foam recovered too slowly the earplugs could fall out before they expanded to contact the ear canal. In addition, if the expanded earplug exerted too much pressure, it would not be comfortable. Accordingly, the inventor quantified the mechanical parameters that would be suitable for his hearing-protective earplugs and found examples of slow recovery foams which met these specifications. Cabot obtained a patent for this invention, United States Patent No. 3,811,437, issued on May 21, 1974. Cabot later initiated reissue proceedings to cure some technical defects and broaden the scope of protection. The patent was reissued on December 6, 1977 as Re. 29,487, the patent in issue in this case.

The broadest claims in the '487 patent are claims 1 and 11. They provide:

1. An earplug of generally cylindrical shape having a diameter of between 3/8 and 3/4 inch, a length of between 1/2 and 1 inch and composed of a resilient plasticized polymeric foam having a sufficiently high concentration of organic plasticizer therein as to provide said foam with a rate of recovery from 60 percent compression thereof to 40 percent compression thereof of from 1 to 60 seconds and an equilibrium pressure at 40 percent compression thereof of from 0.2 to 1.3 p.s.i.

* * *

* * *

11. An earplug having a size and shape adapted to be compressed and inserted into the human ear canal and there allowed to expand and obturate the ear canal, said earplug comprising a resilient plasticized polymeric foam having a sufficiently high concentration of organic plasticizer therein as to provide said foam with a rate of recovery from 60 percent compression thereof to 40 percent compression thereof of from 1 to 60 seconds and an equilibrium pressure at 40 percent compression thereof of from 0.2 to 1.3 p.s.i. [emphasis added].

The invention thus contains six elements: (1) an earplug; (2) of a size and shape to be compressed and inserted into the ear canal; (3) made of resilient plasticized polymeric foam; (4) having a sufficiently high concentration of organic plasticizer to achieve; (5) a rate of recovery within a specified range; and (6) an equilibrium pressure within a specified range.

Cabot first manufactured and marketed this earplug in 1971. The earplugs were made from polyvinylchloride foam as described in the examples in the specification of the patent. The product was a commercial success, and captured more than one-third of the hearing protection market by 1983.

Officials at Specialty became interested in manufacturing foam earplugs after seeing Cabot earplugs in 1976. They used the Cabot patent as a guide in designing their own competing earplugs which admittedly fall within the size, shape, recovery rate and equilibrium pressure criteria of the patent claims. Specialty believed that they could design around the Cabot patent by using an internally plasticized polyurethane foam. They felt that this avoided the limitation that the foam must have a "sufficiently high concentration of organic plasticizer" to produce the specified properties.

"Plasticizer" is a term of art in polymer chemistry and in the plastics industry. Although the chemical compositions of plastics differ, they are all polymers. Polymers are large molecules consisting of repeating units of small molecules. The small molecules, called monomers, are linked together covalently to form the long chains of the polymer molecule. For example, the polyvinylchloride used in the Cabot earplug consists of vinyl chloride molecules strung together in long chains.

The long polymer molecules of plastics can interact with each other to produce structures that are rigid and inflexible. If the interactions that bind neighboring polymer molecules to each other are reduced, the resulting material may be softer, more flexible, and have a lower melting point. "A plasticizer is a material incorporated in a plastic to increase its workability and its flexibility or distensibility (elongation)." J. Sears & J. Darby, The Technology of Plasticizers 2 (1982). "Plasticization ... may be achieved (1) by compounding the given polymer with a low molecular weight compound or with another polymer; and (2) by introducing into the original polymer a comonomer which reduces crystallizability and increases chain flexibility." Immergut & Mark, "Principles of Plasticization," in 48 Advances in Chemistry 1 (1964).

There are two main groups of plasticizers: internal and external plasticizers. Internal plasticizers ... are actually a part of the polymer molecule--e.g. a second monomer is copolymerized into the polymer structure, thereby making it less ordered, and therefore, more difficult for the chains to fit closely together. This softens the polymer.... Another type of internal plasticizer involves the introduction of side chains.... External plasticizers are compounds of low vapor pressure which, without chemical reaction, interact with the polymer, mainly at elevated temperature, by means of their solvent, or swelling power.

Id. at 2. Since external plasticizers are not chemically bound to the polymer molecules, but instead are merely inserted between them, external plasticizers can be extracted from the polymer with solvents.

Plasticizers produce plasticization by a variety of different molecular mechanisms. Different plasticizers are used for different polymers. Plasticizers may even be low molecular weight polymers formed from the same monomers as are used to form the longer polymer chains of the structural plastic. Essentially, "plasticizer" is a functional concept defined by its effect, the softening of a plastic, rather than by the nature of the chemical species involved.

II. Infringement

One critical question in this case is whether or not Specialty's polyurethane foam falls within the limitation in the claims that the foam have a "sufficiently high concentration of organic plasticizer" to achieve the specified recovery rates and equilibrium pressures. The district court held that Specialty's foam does not:

In my opinion, Specialty has avoided infringement by achieving the desired results in a different manner than using an organic plasticizer. A "sufficiently high concentration of organic plasticizer" is a critical limitation on all claims of the patent. The prosecution history indicates that the Gardner invention relates to an externally plasticized polymer--a plasticizer added to the polymer after it has been formed, separately from the polymer. This, I find, is what the words meant to the examiner. There is no acceptable evidence that Specialty has added an organic plasticizer to the polymer structure. The evidence is that it has, as stated above, used chain stopping and under-indexing. They changed the molecular structure rather than adding something to it.

Specialty Composites Corp. v. Cabot Corp., No. 78-3170, slip op. at 12-13 (D.Mass. May 12, 1987).

An issue of infringement raises two fundamental questions: (1) what is patented--this requires interpretation of the scope and meaning of the claim language; and (2) whether the patent, so interpreted, is infringed--whether what is claimed has been made, used or sold by another. Fromson v. Advance Offset Plate, Inc., 720 F.2d 1565, 1569, 219 USPQ 1137,...