CoweN, Ohief Judge,
delivered the opinion of the court:
This is a patent suit under Title 28 U.S.C. § 1498, in which the plaintiff seeks to recover reasonable and entire compensa tion for the alleged unauthorized use of patented inventions. Plaintiff alleges infringement of claims 1 and 2 of U.S. Patent No. 2,381,739 and claims 1 and 2 of U.S. Patent No. 2,421,613. Patent 2,421,613, entitled "Plastic Liner For Containers", hereinafter referred to as the liner patent, is based on an application filed December 14, 1941, by Eeid B. Gray and Joseph C. DeWeese. Patent No. 2,381,739, entitled "Hidden Barrier", hereinafter referred to as the barrier patent, is based on an application filed April 1,1942, by Eeid B. Gray. Plaintiff Martin-Marietta Corporation, referred to as Martin, is the owner by assignment of the entire right, title, and interest in the patents in suit.
The defendant raises the defense, among others, that the patents were obvious to a person having ordinary skill in the art at the time and therefore unpatentable under 35 U.S.C. § 103. Recently, the Supreme Court in Graham v. John Deere Co., 383 U.S. 1 (1966), laid down the guidelines to be followed in applying this statute.
Under § 103, the scope and content of the prior art are to be determined; differences between the prior art and the claims at issue are to be ascertained; and the level of ordinary skill in the pertinent art resolved. Against this background, the obviousness or nonobviousness of the subject matter is determined. Id. at 17
Mindful that "strict observance" of these standards is required (Id. at 18), we turn now to the patents.
LINER PATENT
The invention disclosed and claimed hi the liner patent relates to a liquid hydrocarbon container or fuel cell having an outer supporting structure and an inner flexible cell. Fuel cells are used primarily in military and other aircraft as storage containers for gasoline, oil, or other aircraft fuel. Originally, metal tanks built into the wings or fuselages of aircraft were used, but as the size of airplnaes grew and their wings became increasingly flexible, metal tanks were found to leak. Furthermore, metal tanks did not have self-sealing properties, a necessary requirement for military aircraft in case of gunfire wounds to the aircraft containers.
Beginning in the middle 1930's, plaintiff, under the direction of Gray, developed a flexible fuel container liner or cell which could be folded through a small opening in an airplane wing and which would, when filled with fuel, expand to fill the cavity inside the wing. To solve the problem of self-sealing, the cell was enclosed in an outer layer of soft un-vulcanized rubber. When this rubber came into contact with the gasoline, it would quickly swell and seal any hole. The sealant, in turn, required an outer layer of tough wear-resistant and gasoline-resistant synthetic to protect it and the cell in handling and use.
Prior to the discovery of synthetic rubbers, materials such as shellac, beeswax, metal foil, gold-beater's skin, and lacquer had been suggested as the protective inner lining for gasoline containers. By the late 1930's, synthetic rubbers such as neoprene and thiokol were principally used as inner protective linings.
By the latter part of 1939, it became apparent that the high octane gasolines and aromatic fuels soon to be used by airplanes would cause problems with the neoprene-lined flexible fuel cells. Such fuels slowly diffuse or permeate through neoprene or thiokol; as a result, the sealant will prematurely swell, distort, or blister, destroying the cell. Concurrently with the development of the flexible fuel cell, E. I. duPont de Nemours & Company developed a plastic synthetic linear condensation polymer material more commonly known as nylon. Many of the properties and suggested uses of this product — such as its excellent resistance to fuels and organic liquids — had become generally known to the scientific community by 1939.
In the early part of 1940, Gray, having been informed that nylon was flexible and had aromatic-resistant properties, asked duPont for nylon film to test for fuel cell application. The duPont personnel assisted Gray and DoWeese in developing methods and materials to bond nylon to synthetic and natural rubbers. Beginning in September 1940 and continuing into June 1941, Gray and DeWeese constructed and began testing a gasoline self-sealing type container having a nylon inner lining to determine the effect of high octane gasoline on the container construction. The nylon, situated before the neoprene lining, prevented the aromatic fuels from diffusing through the neoprene and affecting the sealant. On December 15, 1941, Martin filed the Gray and DeWeese application for the liner patent. It contained broad claims directed to nonsealing as well as self-sealing liquid containers having nylon linings.
Plaintiff now asserts that Gray was the first to discover that nylon was sufficiently capable of elastic recovery from distortion created by the pressure wave of a bullet and was shatter-proof under gunfire shock at temperatures far below 0° Fahrenheit so as to be satisfactory as an inner lining material for foldable airplane fuel cells. It should be pointed out, however, that the liner patent does not disclose these properties for the benefit of the public, and that the claims in issue are not limited to airplane fuel cells or self-sealing fuel cells or to containers resistant to aromatic fuels. Father, they extend to all liquid hydrocarbon containers.
Furthermore, the duPont nylon patents earlier disclosed the gasoline-resistant and aromatic-resistant qualities of nylon. The Carothers patent 2,188,332, filed in February 19137 and cited by the patent examiner, states that nylon is a flexible material which "exhibit[s] exceptionally good resistance to greases, oils, most organic liquids, water and vapors." Carothers patent 2,252,554, filed in September 1938, suggests that nylon can be used as an inner lining material for a rubber gasoline hose. Hanford patents 2,281,576 and 2,293,388, not cited by the Patent Office, filed in October 1939 and November 1939, respectively, state: "Rubber may also be coated with polyamides [nylon] to decrease the sensitivity to aromatic hydrocarbons." Gray himself testified that he was attracted to nylon because be bad been informed that nylon was resistant to aromatic fuels.
In view of tbis explicit prior art, it was obvious to a person skilled in tbe liquid hydrocarbon art in 1940 to use nylon as an inner lining for fuel tanks. See B. F. Goodrich Co. v. United States Rubber Co., 244 F. 2d 468, 469-70 (4th Cir. 1957); Perma-Fit Shoulder Pad Co. v. Best Made Shoulder Pad Corp., 218 F. 2d 747, 750-51 (2d Cir. 1955). Therefore, the invention defined in claims 1 and 2 of the liner patent is unpatentable.
BARRIER PATENT
Problems arose with the use of a nylon lining in the flexible fuel cell. Aromatic fuels pick up water which, when sloshed within the cell, softens and detaches the nylon from the synthetic rubber. Moreover, nylon tends to pinch or crack when the cell is sharply folded. Also, it is difficult to manufacture properly a fuel cell with an inside membrane of nylon.
Faced with these problems, Gray conceived the idea of placing the nylon between the neoprene and the sealant instead of before the neoprene. This locates the nylon in a "hidden barrier" position, shielded by the inner synthetic neoprene from damage from the sloshing of water-containing aviation gasoline and yet in position effectively to prevent elements of the aviation gasoline from diffusing into the sealant. In effect, the sealant is protected from aviation gasoline by the nylon, and the nylon is protected from water in the gasoline by the neoprene. Placing the nylon in this barrier position lessens the problems of manufacture present with the liner patent; also, the nylon when used as an intermediate layer does not crack as readily when the cell is folded.
Thus, Gray's improvement over the prior art consisted of shifting the nylon membrane from its position as a liner before the neoprene layer to one behind the neoprene and before the rubber sealant. Gray had reduced the hidden barrier concept to writing as of January 1, 1941, but U.S. Eubber Company with the assistance of Gray began experimenting with nylon sandwiched between two layers of thiokol synthetic rubber on October 1,1941, and that date must be taken as the earliest date of Gray's invention. Of relevance is that James A. Merrill and Dr. Lorin S. Sebrell, employees of Goodyear Tire and Eubber Company, independently suggested in December of 1941 that a nylon layer be placed between layers of .buna synthetic rubber. On December 25, 1941, they in fact constructed a flexible liner having a nylon layer between two layers of buna synthetic rubber.
In deciding whether Gray's invention was obvious to one skilled hi the art at that time, several aspects of the prior art must be stressed. The first is that the several duPont patents filed in the late 19S0's made the aromatic-resistant properties of nylon widely known. Secondly, the use of nylon as an inner protective liner was obvious by 1941 to persons skilled in the liquid hydrocarbon container art. Thirdly, the use of a barrier to prevent diffusion in a fuel cell was not novel. The Eger patent 2,401,627, filed May 16, 1941, discloses a self-sealing aircraft gasoline tank having an inner or first layer of neoprene, a second layer of supporting fabric, a third layer of cellulose acetate, a fourth layer of sealing rubber latex and an outer or fifth layer of supporting fabric.
To be sure, cellulose acetate is an inflexible material which could not be used in the flexible fuel cell involved here. But this does not deprive the Eger patent of all relevance as prior art. Cf., Skee-Trainer, Inc. v. Garelick Mfg. Co., 361 F. 2d 895, 898 (8th Cir. 1966). The Eger patent is relevant in that it suggests that the problem of aromatic fuel diffusion in a neoprene cell may be solved by the use of a membrane situated between the neoprene and'the sealant which would act as a harrier. The specifications themselves of the Eger patent state: "Besides functioning as a stiffening agent, the cellulose acetate inhibits the diffusion of materials such as gasoline and benzol through the tank lining."
Also relevant is patent 2,425,514, filed by Dasher on August 16, 1940. This patent involved a self-sealing airplane fuel cell having a gasoline-resistant inner or first layer, a second layer of sealing unvulcanized rubber that will swell when in direct contact with gasoline, and a third or outer layer of vulcanized rubber. Its specifications state:
It is not essential that the sealing layer be made throughout of a single material, for it is possible and sometimes advantageous to make different portions of it of different materials or even to subdivide the total thickness of the sealing layer into a plurality of portions and interpose other materials of any of the three types, namely, gasoline-impervious, or sealing material, or tough skins.
Thus, both patents disclose the concept found in the barrier patent of positioning a gasoline-impervious membrane behind a layer of synthetic rubber. Gray's improvement over this prior art consists simply of substituting nylon, a material not mentioned in the Eger or Dasher patents but whose aromatic-resistant properties were widely known, for other materials to act as the barrier. Such an improvement was obvious to one skilled in the art. "The cases have consistently held that there is no invention in the substitution of an improved material when it subsequently becomes available." B. F. Goodrich Co. v. United States Rubber Co., 147 F. Supp. 40, 77 (D. Md. 1956), aff'd 244 F. 2d 468 (4th Cir. 1957). Gray's invention was that of a skillful mechanic rather than that of an inventor; as such, it is not patentable. Hotchkiss v. Greenwood, 11 How. (52 U.S.) 248, 267 (1851).
Plaintiff relies upon several nontechnical subtests of validity to demonstrate that the barrier patent here in question was not obvious in 1941. See Notes, /Su$ tests of "Non-obviousness": A Nontechnical Approach to Patent Validity, 112 U. Pa. L. Eev. 1169 (1964). Such "secondary considerations" may be relevant in some instances. Graham v. John Deere Co., supra, at 17-18, 85-36. They are not persuasive here. The presumption of validity accorded to a patent issued by the Patent Office is greatly weakened here by the fact that much of the pertinent prior art was not considered by the Patent Office. Soundscriber Corp. v. United States, 175 Ct. Cl. 644, 649, 360 F. 2d 954, 960 (1966); Zero Manufacturing Co. v. Mississippi Milk Pro. Ass'n, 358 F. 2d 853, 855 (5th Cir. 1966), cert. denied, 385 U.S. 841; Skirow v. Roberts Colonial House, Inc., 361 F. 2d 388, 390 (7th Cir. 1966). The effect of an arbitration decision by the Manufacturers Aircraft Association upholding the validity of the barrier patent is weakened by the fact that the arbitration award has been suspended pending the final decision of this court concerning the validity of both the liner and barrier patents. Other factors such as the commercial success of the patent are not sufficient here to "tip the scales of patent-ability". Graham v. John Deere Co., supra, at 36. When the claimed invention is obvious in light of the prior art, these other facts may not make the patent valid. See Gentzel v. Manning, Maxwell & Moore, 230 F. 2d 341, 343-44 (2d Cir. 1956), cert. denied, 352 U.S. 840 (1956).
One further contention by plaintiff has been considered. In 1950 and 1951, the Department of the Air Force and the Department of the Navy issued notices to plaintiff and its licensees pursuant to the Royalty Adjustment Act of 1942, 56 Stat. 1013, as amended, 65 Stat. 710 (1951), stating that the royalties being charged by plaintiff were unreasonable and excessive. As a result, more than one million dollars in royalties owed to plaintiff by licensees was withheld. Thereafter, plaintiff and defendant entered into a contract dated October 1, 1954, in settlement and compromise of plaintiff's claim. This contract recites that, in consideration of the Government's withdrawal of the notices, the plaintiff grants to the Government a royalty-free license nnder three patents, one of which was the barrier patent in suit, with respect to all fuel cells first placed on order with a manufacturer on or after September 1,1955.
Plaintiff now argues that the Government's withdrawal of its notices concerning royalties on the licensed use of the barrier patent constitutes a recognition by the Government that the barrier patent was in fact valid. But the withdrawal of these notices was not intended to be a recognition of the validity of the patents involved — it was only the quid pro quo in return for the granting of royalty-free licenses. This is amply demonstrated by the parties' negotiations preliminary to the execution of the contract. Plaintiff initially proposed that the contract contain a clause specifically recognizing the validity of the patents. The Government refused to accept such a clause and offered other concessions in return for plaintiff's consent to the elimination of the recognition clause. Plaintiff accepted this compromise. See Martin Company v. United States, 144 Ct. Cl. 714, 718-19, 169 F. Supp. 524 (1959), where the negotiations between the parties are set out at length. In light of these facts, the contract cannot be construed as implied recognition of the validity of the barrier patent by the Government.
Thus, both the liner patent and the barrier patent are invalid on the grounds that they were obvious to one skilled in the art at that time. In view of this determination, we need not consider defendant's alternative defense that the patents were invalid for indefiniteness, or the question of infringement. Plaintiff's petition is dismissed.
FINDINGS OF FACT
The court having considered the evidence, the report of Trial Commissioner Donald E. Lane, and the briefs and arguments of counsel, makes findings of fact as follows:
1. This is a patent suit under the provisions of 28 U.S.C. § 1498 to recover reasonable and entire compensation for the unauthorized use and manufacture for or by the defendant of fuel tanks and cells described in and covered by United States Letters Patent Nos. 2,381,739 and 2,421,613, both issued to The Glenn L. Martin Company. The petition was filed December 28, 1956. Said company owned the patents when the petition was filed and the petition was amended in 1957 to reflect the change of name to The Martin Company. In 1961, The Martin Company merged and consolidated with American Marietta Company to form a new corporation, Martin-Marietta Corporation, a corporation of the State of Maryland, the present plaintiff. The parties have stipulated that the court has jurisdiction of the parties and the issues raised. The parties have stipulated that the issues of validity and infringement of the above patents will first be determined upon proofs, arguments, findings, and conclusion, and that the accounting issues will be deferred until after the entry 'by this court of an order on the questions of validity and infringement. Fuel cells embodying the inventions of these patents and made or sold by plaintiff's licensee during the period in question had affixed thereto a notice complying with the requirements of 35 U.S.C. § 287.
2. As of October 1,1954, The Martin Company, hereinafter called Martin, and defendant entered into a "License Agreement Covering Fuel Cells", plaintiff's exhibit 2 herein, under which Martin granted to defendant a royalty-free license for the life of the patents here in suit. This license does not apply to cells first placed on order with a manufacturer thereof prior to September 1, 1955, and in which defendant acknowledged that it did not have a license under these patents and withdrew certain notices previously issued under the Royalty Adjustment Act of 1942.
3. In 1957, defendant brought into this case as third-party defendants Goodyear Tire and Rubber Company, B. F. Goodrich Company, and Firestone Tire and Rubber Company, who were alleged to have agreed to save defendant harmless to part or all of defendant's alleged liability to Martin. This court in 1958 granted a motion of said rubber companies to dismiss as to them on the ground that defendant by entering the agreement noted above in finding 2 had waived its rights of indemnity against them. The Martin Company v. United States, 143 Ct. Cl. 551, 163 F. Supp. 376, 118 USPQ 366 (1958).
4. Patent No. 2,421,613, entitled "Plastic Liner For Containers", issued to Martin on June 3,1947, on an application filed December 15, 1941, by Eeid B. Gray and Joseph. C. DeWeese, and will be referred to as the liner patent. Patent No. 2,381,739, entitled "Hidden Barrier", issued to Martin on August 7, 1945, on an application filed April 1, 1942, by Eeid B. Gray, and will be referred to as the barrier patent. Plaintiff relies upon claims 1 and 2 of the liner patent and upon claims 1 and 2 of the barrier patent. Both patents relate broadly to hydrocarbon fluid containers such as fuel and oil cells for aircraft, boats, and vehicles. More specifically, both patents relate to containers having walls which are flexible and which are made up of a plurality of layers or plies secured together and at least one of the layers being nylon.
5. Fuel cells are used mainly in military and other aircraft as containers for the storage of gasoline, oil, or other fuel required to be carried in the aircraft. Prior to World War II fuel had been stored in metal tanks built into the wings or fuselages of aircraft, but as the size of airplanes grew and wings became increasingly flexible, metal tanks were found to leak. Furthermore, during the late 1930's it was foreseen that, if war came, self-sealing properties would be needed for the healing of gunfire wounds of aircraft fuel containers Self-sealing properties are achieved by enclosing the fuel container in an outer layer of soft unvulcanized rubber which, in contact with gasoline, quickly swells and seals a bullet hole. Use of sealant rubber, however, meant that tank leakage in normal flight, even in the smallest degree, could not be tolerated because it would prematurely swell, distort, or burst the outer self-sealing layers. Hence there was need for a flexible liner material that would completely protect the sealant rubber. Beginning in the middle 1930's The Glenn L. Martin Company, of which Eeid B. Gray was Chief of Laboratories, pioneered the development of a new type of flexible cells or bags called Mareng fuel cells that could be folded for insertion through a small opening or manhole in the wing, and on being filled with fuel would exactly fit within a cavity inside the wing or fuselage which they were tailored to fit. In connection witli this development Martin was issued the Gray et al. patent No. 2,102,590 in December 1937, not here in suit.
6. In 1938 Martin contracted with Anchor Packing Company and E. I. duPont de Nemours & Company to build Mareng flexible fuel cells having synthetic rubber-coated liners. Martin from 1939 to the middle of 1940 made its own flexible synthetic rubber-coated fuel cells for the airplanes that it assembled. In July 1940 Martin discontinued making fuel cells and granted to U.S. Eubber Company an exclusive license to make fuel cells under the patents owned by Martin. Although the synthetic rubber-coated fuel cells performed satisfactorily for use with most gasolines, it was found that modern high octane gasolines and airplane fuels having significant amounts of aromatic constituents would diffuse through the then used neoprene and thiokol synthetic rubbers and would adversely affect the performance of the fuel cells, particularly self-sealing-type cells mentioned in finding 5.
7. E. I. duPont de Nemours & Company in the 1930's developed a plastic synthetic linear condensation polymer material which was given the coined name nylon. The basic patent (2,071,250) disclosing nylon issued to duPont in February 1937 on an application filed in 1931. DuPont continued to develop several species of nylon which were said to have gasoline- and aromatic-resistant properties. In January 1940 Gray asked duPont personnel for samples of experimental nylon film for the purpose of determining the applicability of nylon for use in the construction of airplane fuel cells. Gray testified on cross-examination that he was attracted to nylon because he had been informed that nylon was resistant to aromatic fuels. Nylon was then extremely difficult to obtain but in the early part of 1940 Gray received small quantities of nylon sheet for experimentation. After receiving a 13-yard sheet of nylon, Gray and DeWeese in September 1940 constructed a liquid hydrocarbon test container having a nylon inner lining in direct contact with gasoline. Tests were completed on the nylon inner layer container in June 1941. DuPont personnel, particularly Dr. Harold S. Holt, during 1940 assisted Martin in developing methods and materials for bonding nylon to synthetic rubbers, mainly neoprene.
8. Gray and DeWeese in the latter part of 1940 and most of 1941 kept in close contact with the U.S. Eubber Company personnel to assist and advise them in the development of production of fuel cells. With the assistance of Gray and DeWeese, U.S. Eubber Company in 1941 developed a liquid nylon coating for applying to the inside of neoprene fuel cells. During the same period duPont also developed a similar liquid nylon coating for fuel cell application.
¡9. In November 1941 Martin received a draft of a tentative duPont patent application by Holt purportedly disclosing and claiming a fuel cell having a nylon inner lining. DuPont's and Martin's patent attorneys met in December 1941 to discuss who had priority to the nylon inner layer invention. The details of the discussion are not in the record. Martin filed the Gray and DeWeese nylon liner patent application on December 15, 1941, directed to broadly claiming hydrocarbon liquid containers having nylon linings, and duPont filed two applications on January 22, 1942, claiming self-sealing fuel containers having nylon linings. One was the Holt application which issued June IT, 1947, as patent No. 2,422,239, and the other was an application by David J. Sullivan which issued August 20, 1946, as patent No. 2,405,986.
10. During the course of his work in 1940, Gray suggested that the nylon layer be positioned behind an inner rubbery layer so that the nylon would not be in direct contact with the fuel (hidden barrier concept). Gray reduced his idea to writing on January 1,1941, plaintiff's exhibit 113. Gray conveyed his idea to U. S. Eubber Company personnel in the spring of 1941. After encountering difficulties with neoprene fuel cells coated with liquid nylon, U. S. Eubber Company in October 1941, with the assistance of Gray, began experimenting with nylon sandwiched between two layers of thiokol which was designated Thiokol LTM. The Air Corps and the Department of Navy in December 1941 informed the airplane fuel cell suppliers that all military airplanes would require aromatic-resistant fuel cells because worldwide military operations were dependent upon airplane fuels refined from foreign crude oils having a high percentage of aromatic constituents. All of the fuel cell suppliers embarked upon a crash program to construct a fuel cell that was sufficiently aromatic-resistant to meet the stringent military requirement. Goodyear Eubber Company, without knowledge of Gray's hidden barrier concept, on December 25, 1941, constructed a flexible liner having a nylon layer between two layers of buna synthetic rubber' which was designated FTL-ION. Both the Thiokol LTM and FTL-ION fuel cell constructions were submitted to the Air Corps for testing. The Air Corps found that both were operable but that the buna-nylon-buna Goodyear construction had superior performance characteristics and thereafter requested all the fuel cell manufacturers to change to the buna-nylon-buna construction in the making of new fuel cells.
11. After World War II, Martin renegotiated the exclusive patent license granted to U. S. Eubber Company to modify the exclusive feature and as of January 1, 1950, Martin had negotiated nonexclusive licenses with the following aircraft manufacturers to make or use aircraft fuel cells and aircraft fuel storage system components protected by 16 Martin-owned patents, including fuel cell patent Gray et al. No. 2,102,590 mentioned in finding 5 and the '613 liner and the '739 barrier patents here in suit: Beech Aircraft Corp., Cessna Aircraft Co., Consolidated Vultee Aircraft Corp., Fairchild Engine & Airplane Corp., Kellett Aircraft Corp., McDonnell Aircraft Corp., Northrop Aircraft Inc., and Eepublic Aviation Corp. As of October 1, 1955, Aeronca Manufacturing Corp., Bell Aircraft Corp., and the Waco Aircraft Co. negotiated similar licenses excluding the Gray et al. patent No. 2,102,590 which had expired. The major fuel cell manufacturers and suppliers, other than U. S. Eub-ber Company, which includes Goodyear Tire and Eubber Company, B. F. Goodrich Company, and Firestone Tire and Eubber Company, and the major aircraft manufacturers that purchased fuel cells therefrom, which group includes Boeing Airplane Company, Douglas Aircraft Company, Grumman Aircraft Engineering Corporation, Lockheed Aircraft Corporation, North American Aviation, and United Aircraft Corporation, refused to enter into a license agreement under the liner and barrier patents.
Validity Issue — LiNER Pateot
12. Tbe invention disclosed and claimed in the liner patent 2,421,613, relates to tanks, cells, or other carrying or retaining structures such as hose and pipe for use in storage or delivery of hydrocarbon fuels for aircraft, boats, and motor vehicles. Fig. 3 of the patent drawing shows a flexible laminated container wall having a first or inner layer of nylon, a second layer of neoprene, a third layer of unvulcanized rubber, and a fourth or outer layer of vulcanized rubber. In describing the construction, the patent specification states:
Where it is desired to protect the tanks or cells by rendering them self-sealing, a multiple layer construction is used, as shown in Fig. 3. Here the inner layer or surface 1, against which the fluid contacts, is composed of a flexible, plastic sheet of any of the materials described above, although, as before stated, nylon, which is a solid synthetic linear condensation polymer, has proved most successful. The synthetic linear condensation polymer preferred for the present _ purpose is that resulting from the condensation of a diprimary diamine and a dibasic carboxylic acid. Backing up the' nylon or other plastic layer is a second layer 2 of soft' neoprene, which is a synthetic rubber product well known in the trade and available in the open market. The succeeding layer 3 is composed of crude, unvulcan-ized rubber, while the outer layer 4 is preferably high strength, cured, vulcanized rubber. The several layers may be secured together in any approved manner as by heat sealing, cementing or the like.
13. Claim 1 reads as follows, indentation added to facilitate understanding:
Claim 1 — Liner '613 patent
A hydrocarbon fluid container having
an outer supporting and retaining structure,
a flexible lining cell comprising
a plurality of layers secured together positioned within the structure to contain said liquid but transmit the pressure load of said liquid to the retaining structure,
said cell having an inner lining in contact with said liquid, consisting of a low permeability, synthetic linear condensation polymer preferably formed by the condensation of a diprimary diamine and a dibasic carboxylic acid.
Claim 2 of the liner patent is similar to claim 1 but recites that the outer dimensions of the cell are substantially equal to the inside dimensions of the retaining structure. Nylon is the synthetic linear condensation polymer formed by the condensation of a diprimary diamine and a dibasic carboxylic acid.
14. Defendant contends that the liner patent specification does not satisfy the requirements of Title 35 U.S.C. § 112 in that it lacks an adequate disclosure and the claims are indefinite. It is found that the description of the invention recited in the claim is adequate to enable a person skilled in the art to practice the invention. It is further found that the claims are sufficiently definite to point out the scope and boundaries of the claimed invention, even though there are several inconsistencies in the patent description as to the scope and boundaries of the invention.
15. At the trial, defendant's patent expert listed the following prior patents and publication as pertinent to the disclosure of claims 1 and 2 of the liner patent in suit:
United States Patents
British Patent
Societa Italiana Pirelli_ 301,089_ 1929
Publication
The Aircraft Engineer, Page 46G_ 1-27-1927
(The Problem of Safety Fuel Tank — Boothby)
Defendant's requests for findings with respect to the liner patent refer to the following additional prior patents:
United States Patents
Macbeth_ 1,325,448_ 1919
Oden_ 1,756,698_ 1930
Kraft_ 1,779,397_ 1930
Defendant's post trial brief refers to the following additional prior patents as pertinent to the liner patent:
United States Patents
Greene_ 2,034,654_ 1936
Gray & DeWeese_ 2,406,679_ filed 5-31-1940
Eethorst_ 2,406,903_ " 7-29-1940
16. During the prosecution of the application for the liner patent in the United States Patent Office, the patent examiner and the Board of Appeals considered Thacher '305, Kraft '397, Carothers '332 and '554, and Pirelli British '089 listed in the preceding finding and also cited:
British Patents
Shepherd _ 189, 848-1922
Hareourt-Smith _ 538, 873_1941
Patent claims 1 and 2 of the liner patent here in suit were allowed by the patent examiner after the allowance of patent claims 3 and 4 by the Patent Office Board of Appeals.
17. None of the references cited in finding 15 discloses a hydrocarbon container having a nylon inner layer for protecting successive flexible layers from the deleterious effects of hydrocarbon liquids. Prior to the discovery of synthetic rubbers several gasoline-resistant materials were suggested for use as inner liners of gasoline containers. Thacher '305 discloses the use of shellac to protect self-sealing rubber layers. Cleghorn '670 and '305 disclose self-sealing fuel tanks having a gasoline-resistant inner layer of Turkish birdlime prepared from the fruits of certain trees. Macbeth '443 suggests several layers of gum lac as a protective liner for containing hydrocarbon liquids. Oden '698 suggests the use of beeswax, castor oil, various glues, glycerine, gum, molasses, shellac, or lacquer as possible protective liner materials for rubber gasoline hose. Kraft '397 discloses the use of gelatine as a gasoline-resistant material. Pirelli British Patent '089 discloses the use of a metal foil as a liner material to protect rubber self-sealing layers from gasoline. The Aircraft Engineer article suggests the use of a liner made for gold-beater's skin having a coating of cellulose dope thereon to prevent diffusion of gasoline and benzene.
18. In the late 1930's synthetic materials were used as lining material for hydrocarbon containers. Gasoline containers having neoprene synthetic rubber inner linings are disclosed in Gray et al. '590, Watter '097, Klose '184, Eger '627, Eethorst '903, and Dasher '514. Klose '184 also suggests the use of thiokol synthetic rubber as an inner liner material. Merrill '701 discloses a fuel tank having an inner lining made of a rubber derivative called "Plioform." Griffith '172 discloses the use of polyvinyl acetal resin as an inner liner for containing gasoline or aromatic fuels. Dasher '514 also suggests the use of cellophane, poly-ethylene polysulfide, polyvinyl alcohol plasticized with glycerine, polyvinyl chloride plasticized with aromatic liquids, and rubbery co-polymer of butadiene and acrylonitrile as good gasoline-resistant materials.
19. In the 1930's E. I. duPont de Nemours & Company developed a synthetic linear condensation polymer generally known as nylon. Carothers '250, mentioned in finding 7, is the duPont patent claiming nylon and processes for making the same. Carothers '332 filed in February 1937 and issued in January 1940 pertains to the use of nylon as a coating on a flexible base material such as rubber. The specification states:
Polyamides are especially suitable for coating such materials since they are very flexible, show good adhesion, are durable, and exhibit exceptionally good resistance to greases, oils, most organic liquids, water, and vapors.
Carothers '554 filed in September 1938 and issued in August 1941 pertains to a species of nylon and the process for making the same. The specification states:
Bubber is another material to which polyamide coatings can be applied with good results, e.g. in the preparation of gasoline hose (as a liner), rubberized cloth, . . .
Carothers '555 pertains to a species of nylon and the process for making the same. Hanford '576, filed in October 1939 and issued in May 1942, also pertains to a species of nylon and the process for making the same. In describing the attributes of nylon the Hanford '576 specification states: "Rubber may also be coated with polyamides to decrease the sensitivity to aromatic hydrocarbons." Hanford '388 filed November 1939 and issued in August 1942 pertains to another species of nylon and the process for making the-same. The Hanford '388 specification also states: 'Rubber may also be coated with polyamides to decrease the sensitivity to aromatic hydrocarbons." The duPont patents clearly suggest -that rubber coated with nylon is resistive to gasoline and aromatic hydrocarbons and could be used as a lining material for a hydrocarbon liquid container such as a hose.
20. During the prosecution of the liner application before the Patent Office, applicant argued that Gray discovered that nylon had a low permeability to aromatic fuels. This argument persuaded the Patent Office Board of Appeals to allow the issuance of the liner patent. Gray admitted on cross-examination that he was attracted to nylon because he had heard that nylon had aromatic-resistant properties. The duPont patents Hanford '576 and '388 filed in 1939 but not cited by the Patent Office state that 'Rubber may also be coated with polyamides [nylon] to decrease the sensitivity to aromatic hydrocarbons."
21. It is found after considering the history of the hydrocarbon liquid container art described in findings 5-9, the independent disclosure of the invention by duPont at about the same time described in finding 9, the state of the prior art described in findings 15-19, the Patent Office proceeding described in finding 20, and the surrounding circumstances described in finding 8, that it was obvious to a person skilled in the hydrocarbon liquid container art during the early part of 1940 to use the new material nylon as an inner lining for hydrocarbon liquid containers. Therefore it is concluded that claims 1 and 2 of the liner patent No. 2,421,613 are invalid.
Validity Issue — Barrier Patent
22. The barrier patent, 2,381,739', also discloses and claims a hydrocarbon liquid container having a flexible wall structure formed by a plurality of laminated layers. Fig. 1 of the patent drawings shows a laminated wall structure having a first or inner layer of neoprene, a low diffusion second layer or membrane of nylon, and an outer layer of fabric impregnated with soft vulcanized rubber. In describing this construction the specification states:
In Fig. 1 there is shown a flexible non-elastic fabric for particular use in preparing "Mareng" cells for holding hydrocarbon fuels and oils. The cells are a well-known development of the Glenn L. Martin Company and are now being used in many modern types of aircraft. The inner layer 1 is composed of a hydrocarbon resistant synthetic rubber lamination which is preferably prepared from neoprene, and secured to the rear surface thereof is a backing barrier or membrane numeral 2 composed of a synthetic linear condensation polymer, or similar plastic material. Exterior of the hidden barrier is an external fabric 3 impregnated with either a soft vulcanized wear-resistant lamination, or if desired, one of the synthetic rubbers may be substituted.
Fig. 4 shows a cross section of a hose having a nylon barrier layer between concentric tubular layers of synthetic rubber.
23. Claim 1 of the barrier patent is representative and reads as follows with indentation added to facilitate understanding:
Claim 1 — Barrier '739 Patent
A hydrocarbon liquid container having a flexible wall structure comprising
a plurality of layers of synthetic plastic materials having rubber-like physical characteristics, said layers being bonded together to form a unitary wall structure, and
an intermediate membrane having lower diffusion characteristics than the adjacent layers, said membrane consisting of a plastic material formed from a synthetic linear polyamide.
Claim 2 recites that the membrane consists of "a plastic material formed from a synthetic linear condensation polymer, preferably formed by the condensation of a diprimary diamine and a dibasic carboxylic acid."
24. Defendant asserts that James A. Merrill and Dr. Lorin S. Sebrell were the first inventors of the invention claimed in the barrier patent instead of Gray. Sebrell was Director of Research and Merrill was the section head assigned to fuel cell development work at the Goodyear Tire and Rubber Company during the relevant period, 1941-1943.
25. On March 19, 1943, Merrill and Sebrell filed a patent application as joint inventors of the nylon barrier invention. The Patent Office on September 12, 1946, declared Interference No. 82,580 between the Merrill and Sebrell application and Gray barrier patent. Merrill and Sebrell alleged in their Preliminary Statement before the Patent Office that their date of conception and reduction to practice of the invention was in December 1941. Gray alleged in his Preliminary Statement that his date of conception was on or about April 15, 1940, and that his date of reduction to practice was September 26, 1940. After an exchange of Preliminary Statements, Merrill and Sebrell, with the consent of Goodyear, expressly abandoned the contest. On April 11, 1947 the Patent Office terminated the interference proceeding.
26. On December 1,1941, the Navy Department informed the suppliers of fuel cells that due to the difficulty of obtaining gasoline outside the United States, planes in foreign service would be using blended aromatic fuels requiring fuel cells with aromatic-resistant liners. On December 16, 1941, soon after the bombing of Pearl Harbor, the Air Corps notified the fuel cell manufacturers that it also desired fuel cells that were resistant to aromatic fuels. Merrill testified that he and Sebrell thought of the hidden barrier concept in December 1941, but was unable to establish the exact day. On December 25,1941, Goodyear started testing a fuel cell liner having a nylon layer intermediate buna-synthetic rubber layers. The testing was completed by February 11,1941, at which time the Navy Department approved the construction for use in Navy aircraft. It is found that the earliest date of invention to which Merrill and Sebrell is entitled is December 25,1941.
27. On September 26, 1940, Gray received from duPont a 13-yard roll of nylon which was used in the construction of a test fuel cell called "Tank 19" described in plaintiff's exhibit 128. The tank was constructed with a first layer of nylon sheet, a second layer of neoprene, a third layer of crude rubber, and an outer layer of floating rubber. The nylon layer was glued to the neoprene by a nylon and Bostick M-20 cement. Plaintiff suggests that the construction and testing of "Tank 19" was a reduction to practice of the invention claimed in the barrier patent. Specifically the plaintiff contends that the inner layer of nylon is a layer of "synthetic plastic materials having rubber-like physical characteristics" and that the nylon and Bostick M-20 cement is the "intermediate membrane". The barrier patent specification does not support such an interpretation. Furthermore, the purpose of the nylon and Bostick M-20 cement was to cement the inner nylon layer to the neoprene and not for the purpose of establishing a hidden barrier "having lower diffusion characteristics than the adjacent layers". It is found that "Tank 19" was not a construction of the invention recited in claims 1 and 2 of the barrier patent but is instead a construction of the invention claimed in the liner patent.
28. On January 1, 1941, Gray reduced his hidden barrier concept to writing, plaintiff's exhibit 124. The writing was witnessed by a fellow employee, John W. Neale. Dr. William J. Clayton, Manager of the New Products Development Department of U.S. Rubber Company, testified that Gray conveyed to him the hidden barrier concept "a long while before Pearl Harbor". Clayton testified that U.S. Rubber Company started experimenting with nylon material for fuel cells in the late summer or early fall of 1941. He stated: "The first record that I found of our working with the nylon as a barrier was September 26, 1940", referring to a notebook dated September 26, 1941, plaintiff's exhibit 144, which shows that an experiment was conducted on October 1, 1941, using nylon in cooperation with Thiokol synthetic rubber. The Thiokol-nylon-Thiokol lamination was called Thiokol LTM. The record shows that U.S. Rubber Company built several 5-gallon test fuel cells on February 12, 1942, and a B-26 fuel cell on February 23, 1942, using Thiokol LTM. In March 1942 the Air Corps conducted gunfire test of the B-26 fuel cell and granted temporary approval for the use of Thiokol LTM in the construction of fuel cells ordered by the Air Corps, but soon thereafter the Air Corps requested that all new fuel cells be made of the buna-nylon-buna Goodyear construction. All of the work done by the U.S. Bubber Company concerning fuel cells was done with the knowledge and frequent assistance of Gray. Gray filed his application for the barrier patent on April 1,1942.
29. There is not a sufficient showing that Gray, in the 9-month period between January 1,1941, and October 1,1941, was diligent in an effort to reduce his hidden barrier concept to physical form in a liquid hydrocarbon container. In fact it was thought to be of little practical value during this 9-month period. It is found that the earliest date of invention to which Gray is entitled is October 1,1941.
30. Summarizing findings 26 through 31, it is found that Gray developed the nylon barrier prior to Merrill and Se'brell.
31. Defendant asserts that the barrier patent claims 1 and 2 are invalid on the grounds that the invention was not new or novel at the time it was made, and that the invention was obvious to those skilled in the art at the time the invention was made.
32. In support of its contention, defendant during trial relied upon the following patents and publication:
United States Patents and Publications
(The Problem of Safety Fuel Tank — Boothby)
Defendant in its post trial brief calls attention to the following patents which will not be considered as references against the barrier patent:
Geer_ 1,801,666_ 1931
Berkowitz_ 2,146,559- 1939
Carothers_ 2,191,367- Feb. 20, 1940
Voorhees_ 2,194,341_ Mar. 19, 1940
Waiter_ 2,331,097_ filed Apr. 11, 1941
Of the above patents Geer '666, Voorhees '341, and Carothers '332 and '367 were considered by the patent examiner and the Patent Office Board of Appeals.
33. The references cited in finding 35 may be classified into two broad categories: those pertaining to the construction of fluid containers for difficult-to-contain liquids or gases and those pertaining to the processes for making nylon or nylon coatings. None of the references discloses the use of nylon as an intermediate membrane in the wall construction of a liquid hydrocarbon container. Five patents, Flagg '718, Cleghorn '670 and '305, Eger '627, and Dasher '514 disclose a low diffusion membrane or layer intermediate two wall layers of a liquid hydrocarbon container. Three patents, Sullivan '986, Griffith '172, and Holt '239 and the Aircraft Engineer article are limited to a low diffusion inner lining as opposed to a hidden barrier layer. Applications for the Sullivan '986 and Holt '239 patents were filed subsequent to the date of invention of the barrier patent as found in finding 30 and thus are irrelevant to the issue of novelty. As previously mentioned in reference to the liner patent, the four patents, Carothers '332 and '554 and Hanford '576 and '308, assigned to E. I. duPont de Nemours & Company, pertain to nylon and nylon coatings or processes for making same.
34. Eger patent '627 is the most pertinent single reference asserted by the defendant. Eger '627 discloses in Fig. 6 a self-sealing aircraft gasoline tank having an inner or first layer of neoprene, a second layer of supporting fabric, a third layer of cellulose acetate, a fourth layer of rubber latex, and an outer or fifth layer of supporting fabric. The specification states:
In order to increase the rigidity of the fabric 20, the surface opposite the Neoprene coated surface is pro vided with a film 21 of cellulose acetate. This film is applied to the fabric in several coats, the first coat preferably being relatively thin, that is, it is diluted with a solvent such as ethyl acetate in order that it may penetrate the interstices of the fabric. It has been found that a total of 5 coats of cellulose acetate will function as a desirable stiffening medium, the total thickness of the deposit being approximately .005 inch. Besides functioning as a stiffening agent, the cellulose acetate inhibits the diffusion of materials such as gasoline and benzol through the tank lining.
Eger discloses an intermediate membrane of cellulose acetate baying low diffusion characteristics, but does not disclose the use of nylon as the intermediate membrane.
35. Dasher '514 discloses in Fig. 1 a self-sealing airplane fuel cell having a gasoline-resistant inner or first layer, a second layer of sealing unvulcanized rubber that will swell when in direct contact with gasoline, and a third or outer layer of vulcanized rubber. The following materials are suggested as gasoline-resistant: cellophane, metal foil, polyethylene, polysulfide, polyvinyl chloride plasticized with gasoline-insoluble aromatic liquids, neoprene, and rubbery co-polymer of butadiene and acrylonitrile. The specification states:
It is not essential that the sealing layer be made throughout of a single material, for it is possible and sometimes advantageous to make different portions of it of different materials or even to subdivide the total thickness of the sealing layer into a plurality of portions and interpose other materials of any of the three types, namely, gasoline-impervious, or sealing material, or tough skins.
Dasher suggests that a gasoline-impervious layer may be placed interposed between two sealing layers. Dasher does not disclose or suggest that nylon be used as the gasoline-impervious material.
38. Cleghorn '670 and '305 disclose the use of Turkish birdlime as a hidden barrier material in the construction of liquid hydrocarbon containers. Flagg '718 discloses a hose for communication hydrocarbon liquids having a wall construction with a first inner layer of leather, a rubber protective second layer of gelatine and molasses, and an outer layer of rubber. The inner layer of leather is to hold the gelatine mixture in place.
37. Griffith '172 discloses a self-sealing fuel cell having a laminated wall construction with a fuel-resistant inner layer of polyvinyl acetal resin known as "Saflex" to protect the rubber sealing material. Griffith does not disclose a barrier concept or the use of nylon. The Aircraft Engineer article suggests an inner layer of gold-beater's skin for use as a fuel-resistant material in the construction of aircraft fuel cells.
38. DuPont patents, Carothers '332 and '544 and Hanford '576 and '388 are discussed in finding 19.
39. The Patent Office Board of Appeals held that claims 1 and 2 were patentable when considering Geer patent '666 in view of Carothers patent '332. Geer '666 discloses a balloon wall structure for containing hydrogen or helium having an aluminum foil layer between two outer layers of rubber. Geer is not concerned with a fuel-resistant wall structure for a liquid hydrocarbon container. The Flagg '718, Cleghom '670 and '305, Eger '627, and Dasher '514 patents are considerably better references in view of the claimed invention than the Geer reference.
40. It is found after considering the history of the hydrocarbon liquid container art described in findings 5-9, the independent development work by Goodyear at about the same time described in finding 28, the state of the prior art described in findings 35-41, the Patent Office proceeding described in finding 42, and the surrounding circumstances described in finding 10, that it was obvious to a person skilled in the hydrocarbon liquid container art in October 1941 to position the nylon barrier behind the synthetic rubber inner layer in the construction of hydrocarbon liquid containers. Therefore, it is concluded that claims 1 and 2 of the barrier patent 2,381,739 are invalid.
CONCLUSION OF LAW
Upon the foregoing findings of fact, which are made a part of the judgment herein, the court concludes as a matter of law that plaintiff is not entitled to recover, and the petition is dismissed.
The court acknowledges the assistance it has received from the report of Trial Commissioner Donald E. Lane. We concur in the result he reached and have relied heavily upon his opinion.
In recognition of tills development, Martin obtained in 1937 Gray et al. patent 2,102,590, not here in suit.
A controversy developed between duPont and Martin personnel concerning who had priority to the nylon lining invention, and, in December 1941, the respective patent attorneys of the parties met to consider the subject. The report of the meeting is not a part of the record. However, duPont did file the Holt and Sullivan applications for patents on January 22, 1942, these applications maturing into patents 2,422,239 and 2,405,986, respectively, containing narrower claims directed to self-sealing fuel containers having nylon linings.
During the prosecution before the Patent Office, it was argued that Gray discovered that nylon had a low permeability to aromatic fuels which materially influenced the Patent Office to issue the liner patent. However, during the trial, Gray, on cross-examination, did admit that he had previously known that nylon had aromatic-resistant properties. It is doubtful that the claims in issue of the liner patent would have been allow'ed by the Patent Office had it known this fact or had it cited either of the Hanford patents '576 or '388.
Plaintiff contends that Gray reduced Ms Mdden barrier concept to physical form in September 1940 by the construction of a fuel cell having a nylon inner lining bonded to neoprene by a nylon cement, suggesting that the nylon cement is the intermediate nylon membrane that is recited in the barrier patent claims. It is clear that the purpose of the nylon cement was to bond the first inner layer of nylon to the neoprene layer and is not an intermediate barrier layer having lower diffusion characteristics than the adjacent layers as shown or claimed in the barrier patent. It was not until October 1, 1941, after encountering problems with the fuel cells having an inner nylon lining, that development was begun by the U.S. Rubber Company personnel, with Gray's assistance to construct a fuel cell having a nylon layer behind a thiokol synthetic rubber layer.
The Hanford patents '576 and '388, the Eger patent '627, and the Dasher patent '514 were not before the Patent Office.